WO2002041465A2

WO2002041465A2 - High capacity compact power source and control features

Info

Publication number: WO2002041465A2
Application number: PCT/IB2001/002169
Authority: WO
Inventors: Yaron Shrim; Menachem Givon
Original assignee: Electric Fuel (E.F.L.) Ltd.
Priority date: 2000-11-20
Filing date: 2001-11-19
Publication date: 2002-05-23
Also published as: WO2002041464A3; WO2002041464A2; AU2002223927A1; WO2002041465A3; AU2002215146A1

Abstract

A portable charger employs metal air battery cells and has enough charge and current capacity to permit simultaneous use and charging of an attached appliance with a secondary battery. This allows, for example, a cell phone user to use a cell phone for extended periods of time. Preferably, the primary charger may have an extension cord to allow the primary batteries to be located remotely from the appliance, for example attached to a belt. An adapter provides various control functions such as voltage and current control, and a residual capacity meter. A mechanical device controls gas exchange from the primary battery.

Description

DESCRIPTION High Capacity Compact Power Source and Control Features

Field of the Invention

This invention relates generally to power sources. More particularly, the invention relates to high capacity compact portable power sources.

Background of the Invention Most high energy drain portable electronic devices are powered by secondary or rechargeable batteries rather than primary or disposable batteries (i.e., single use disposable batteries). Examples of such high-drain devices are mobile communication devices (e.g., cellular telephones), personal digital assistants (PDAs), notebook computers, camcorders, and cordless hand-tools. The use of primary batteries (e.g., alkaline batteries) in high energy drain devices is, over time, cost prohibitive. The life-span of a typical primary or single-use batteries is short due to the high energy drain of the appliance and would result in the use of many primary batteries over the life of the device. Further, the weight of primary batteries is, for a given energy storage capacity, greater than that of secondary batteries. (Although, single use batteries have higher energy density than rechargeable.) The weight of the primary batteries in conjunction with their relatively short life-span when used in high energy drain devices, would discourage a person from carrying enough primary batteries for long-term operation of the device (e.g., while on a 3 day trip). For example, a cellular telephone with alkaline batteries would operate without replacing the batteries about as long as a single charge of a nickel-metal-hydride battery. However, in the long term the use of alkaline batteries would cost far more per unit energy because once the alkaline batteries have lost their energy they would need to be replaced by new alkaline batteries. On the other hand, the nickel-metal hydride battery can be recharged after each discharge. The nickel-metal hydride battery, though initially expensive, may costs only pennies to recharge and may last years depending on the device. New primary battery technologies have emerged that have, in principle at least, the ability to offer sufficient energy and power at a sufficiently low cost to make these disposable batteries attractive for high-drain portable devices. One such technology is metal-air batteries, for example zinc-air batteries. In a zinc-air battery, one of the electrodes of the battery uses oxygen that can be supplied by ambient air. Since oxygen is available everywhere, a zinc-air battery need house only one consumable electrode. Because of this, the energy capacity per unit weight is magnified greatly. Unfortunately, the intrinsic benefits of electrochemical cells that use air as an electrode are attended by some serious technical drawbacks.

Typical zinc-air cells, such as those in hearing aid batteries, have holes in their casings to admit air. These holes permit oxygen needed for operation to diffuse into the cell and also permit water vapor from the electrolyte in the cells to escape. For larger batteries with high power capacity needed for the high energy drain devices, multiple metal-air cells may be used. In such large combinations, the exchange of these gases becomes a real problem as discussed below.

Although zinc-air batteries have, for a given volume high energy densities, they are moderately low on power. To increase their power, large amounts of oxygen must be supplied. This creates some obvious design problems for hand-held consumer devices. Many small portable electronic devices have battery compartments that are narrow with a small opening for exchanging the batteries when they are depleted. These configurations provide little area for the exchange of air gases with the outside. A typical zinc-air battery for use in a hearing aid would require a total surface area of approximately 200 cm² to generate sufficient power to operate a typical digital telephone. To expose such a large area to the outside would require a dramatic rethinking of the way batteries are housed by appliances.

Further, each high power drain device may have a different housing configuration and would require the metal-air batteries to be packaged in a variety of different packages so as to mate with one or more of the devices they are to power. For example, a metal-air battery pack which could be used to replace the secondary battery of one mobile telephone made by one manufacture would not likely mate properly with a mobile phone made by a different manufacturer due to different dimensions of the battery pack housing, connector styles, and/or different telephone case styling. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes.

An additional problem with metal-air batteries is the fact that, because oxygen must enter the battery, water vapor can leave the battery. As such, metal-air batteries are susceptible to desiccation in low humidity environments, which can destroy their ability to function.

Leakage of water between or onto metal-air batteries is also a concern. Water from a multitude of sources can potentially enter the battery pack. Intruding water can then contact the metal-air battery cells and cause electrical shorts. Sources of such water include sweat from the person handling the device, moisture from speaking near or into the device, or simply from water spilled onto the device.

Finally, portable electronic devices place constraints on battery weight and volume. The battery cell must be sized to deliver required power cost effectively while also conforming to the various shapes, sizes, voltages, amperages, etc. of cellular telephones, notebook computers, camcorders, and cordless hand-tools. The design and styling variations between various portable electronic devices along with the air flow required for proper metal-air battery operation and water retention result in a complex set of design considerations for providing primary metal-air batteries for a wide array of portable electronic devices. Ideally, a particular battery pack should be designed to connect to, and provide the power needs of, more than one type of electronic device to reduce the number of various battery pack designs.

Summary of the Invention

The present invention includes a versatile universal battery pack power supply particularly useful as a portable charger and supplemental power source for a variety of portable electronic devices. A versatile universal battery pack power supply device is provided which includes one or more high current density batteries, for example metal-air primary battery (i.e., disposable) cell(s), capable both of powering the high power devices during operation and providing secondary battery charging for such devices The battery pack power supply may have sufficient current capacity to support the use of a portable electronic device in all modes of operation. The battery pack power supply may further have sufficient charge capacity to charge the secondary battery of the portable electronic device one or more times. The battery pack power supply may also have sufficient current capacity to power the continued operation of the portable electronic device while charging the secondary battery of the portable electronic device (one or more times).

The battery pack power supply has various physical characteristics which make it well suited to act as a supplemental portable power source. The battery pack power supply is preferably designed to be small in size so that it may be carried easily by a person on the go. For example, the battery pack power supply may be small enough to fit in a shirt pocket and/or small enough to fit comfortably in the palm of a person's hand. The battery pack power supply is preferably lightweight so that it can be easily carried during travel. For example, a small lightweight battery pack can be created by including fewer battery cells (e.g., metal-air battery cells) than would be needed to meet the voltage requirements of the portable electronic device. In this case, the battery pack power supply could, for example, be equipped with a voltage boost circuit which will step-up the voltage from the battery cell voltage to the portable electronic device's recommended voltage level.

The battery pack voltage supply may be connected to the portable electronic device with a connection wire so that the battery pack can be carried in a person's pocket or purse, rather than the battery pack case being physically attached to the portable electronic device, and supply power to the portable electronic device and its secondary battery. This convenient packaging is particularly useful when using the portable battery pack power supply to power and/or charge the secondary power supply of, for example a mobile telephone, when the mobile telephone is in use.

In general, the portable battery pack power supply may include a battery pack case for housing one or more high current battery cells and an electric interconnect which enables the battery pack to power the portable electronic device remotely. The battery pack case is preferably made of a durable lightweight water-resistant material, such as plastic. If the battery pack includes battery cells such as metal-air batteries that require air to operate, then the battery pack case will also include one or more air access holes. The air access holes are provided in sufficient number and size to ensure adequate airflow for the operation of the metal-air batteries. Preferably, the number and size of holes is sufficient to ensure adequate air flow even when some of the air access holes are blocked during use of the battery pack. The battery pack case is also preferably designed so that there is a distance between the air ingress surface of the metal-air battery and the battery pack casing. For example, the case may have a concave inner surface (and therefore a convex outer surface) opposite the air-ingress surface of the metal-air battery. The convex shape of the outer surface of the case also may ensure that a limited number of the air ingress holes get blocked at one time. One or more standoffs or posts may also be included on the case outer surface to further ensure there is minimal air flow access hole blockage when the battery pack case is set on a flat surface.

The portable battery pack power supply may include one or more battery cells of any physical shape, for example round, cylindrical, prismatic, etc. However, the battery cells should be of a physical shape which can pack the power and current capacity required of high power devices into a small physical space so as to achieve small size and light-weight. In one preferred embodiment, the battery cells are made in a prismatic shape and are metal-air batteries so as to maximize the current density and current capacity in the smallest volume possible by achieving high packing density.

The portable battery pack power supply case may be made in any convenient geometrical shape, e.g., a disk, an elongated rectangle cube (stick shape), a square cube, etc., which would be comfortable for the user and useful in housing the battery cells. The shape depends on the shape of the cells and their arrangement, which are preferably such as to maximize packing density consistent with gas exchange requirements. In one preferred embodiment, the case is a generally cubic in shape and houses four battery cells, each of a prismatic shape. A first pair of cells are arranged side-by-side along a longer dimension and another two cells having the same side-by side arrangement are placed back to back with the first two cells. In another preferred embodiment the case has a higher aspect ratio by lining up the shorter dimension of each pair of cells in the same back to back configuration.

The portable battery pack power supply also may include a means for arranging and retaining the one or more battery cells housed within the battery pack case. The means for arranging and retaining the battery cells may be a receptacle, partial walls, or posts sufficient to hold the battery cell(s) in predetermined locations and may be separate or integral to the battery pack case. Further, the battery pack case may house a moisture barrier material which will retain any electrolyte leaking from the battery cells or an absorbent material to absorb any leaking electrolyte. The moisture barrier or absorbent material may be separate from, or integral with, the means for arranging and retaining the battery cell(s). In one variation, the moisture barrier may be, for example, a polypropylene or Teflon envelope that surrounds the housing and metal air battery cells. In another variation, the moisture barrier may be, for example, a polypropylene film place over an opening in the metal air battery cell housing. In still another embodiment, an absorbent material such as Co-Form® manufactured by Kimberly-Clark® may be used between the cells and the casing openings.

The electrical interconnect enables electrical comiection of the batteries to a portable electronic device, for example a personal digital assistant, so that the battery pack case may be physically remote from the portable electronic device case while providing power to the portable electronic device. This allows the user to place part of the weight of the combined appliance where it is borne more easily. For example, the added weight of an auxiliary battery in a hand-held cell phone could become onerous, so the charger/auxiliary battery may be placed in a shoulder bag or pocketbook or hooked on a belt, etc. The interconnect may include, for example, a cable with a connector on eitlier end. One electrical comiector will connect the cable to the portable battery pack power supply and another connector will connect to the portable electronic device. To simplify interconnection with a minimum of fumbling, the cable ends are preferably of different shape to ensure that the respective ends are not easily transposed. One or both connectors are preferably of symmetrical design so that proper connection is insured, regardless of orientation. In one preferred embodiment, the connector for the battery pack power supply is bilaterally symmetrical so that, when used, it closes the circuit connections to provide a battery pack power supply in which two or more battery cells are connected in parallel. In this way, the battery cells to be connected in parallel will not experience a slow parasitic discharge caused by slight differences in potential of the cells and will only be connected in parallel when the battery pack power supply is connected to the load. Of course, the cable could be connected to the battery pack case via a permanently affixed pigtail secured to the battery pack case. In a further variation, the cable may be retained in the battery pack case and may be wound on a spool for compact storage and quick retrieval. For maximum versatility a universal connector may be used for connecting to a plurality of different types of portable electronic devices.

The portable battery pack power supply may further include a voltage booster and/or a controller. The voltage boost circuit is used to boost the voltage of the battery cell(s) from the combined battery cell voltage to the desired/required voltage of the portable electronic device. The controller may control the current drawn from the battery pack power supply by controlling the current from the supply side. Controlling the discharge current (discharge current limiting) is important so as to ensure the battery cells in the battery pack are not discharged too quickly. Discharging batteries too quickly may thereby reduce the maximum power available from the battery. This is particularly true for metal-air batteries, which can experience asymmetry in the chemical reaction of air in the battery cells from moisture migration such that a portion of the reactive electrode is not fully utilized during discharge. In any case, in one variation, the voltage booster and/or controller may be included inline with the interconnect cable. In another variation the voltage booster and/or controller may be incorporated into the battery pack case or constructed with a connector so as to be detachable from the battery pack unit.

The controller may be capable of controlling charging to prevent wasting battery pack power supply energy and overcharging the secondary battery. For example, the controller may include a timer which automatically turns off the charging in a predetermined time frame based on various factors such as the type of battery being charged and the present capacity (level of charge) in the secondary battery. The controller may operate through the interconnect cable simulate the appropriate handshake with the electronic device to determine the particular type of secondary battery connected to the electronic device and set the control parameters accordingly. The battery pack power supply may have an IR or RF port coupled to the controller for receiving secondary battery type information, software, and/or parameter updates from an appliance. Further, the controller may operate to allow charging only when the capacity of secondary battery falls below a predetermined level. The trigger level for charging may be selectable by the user. The controller may monitor the residual capacity of secondary battery and may recharge the secondary battery with the batter pack power supply only when a user-selectable threshold indicative of the percent of depletion desired is reached. Thus a user may select and set the controller to accept recharging only when the charge of the secondary battery is below 70 percent if the user wants more efficiency out of the battery pack power supply. However, if the user is not as concerned about efficient use of the battery pack power supply the user might select a recharge threshold of 95 percent to trigger the controller to activate recharge of the secondary battery. Further, the controller could be programmed to set a particular trigger threshold based on profile and user status. For example, the trigger level may be 80 percent for vacation, 90 percent for business, or 50 percent for home use, and the user may merely select at any given time whether they wish to operate the battery pack power supply on the "vacation" profile, the "business" profile, or the "home" profile. These profiles may be customized and added to by the user. Standardized profiles of users that the buyer can select to use to optimize the charging of the secondary battery. The controller may be a "smart" controller with processing capabilities similar to those of a microprocessor or be configured with a microprocessor. The controller with such microprocessor capabilities may provide prompts such as "Are you at home?" "Are you on the road?" and/or "Are you on vacation?" via the display. In one variation, the controller may download profiles and profiling software from the Internet and set parameters on the smart controller using RF, IR or coupled connections. Further, the controller may have processor capabilities that can learn from the user's actions over time using, for example, artificial intelligence. In this way, the controller can create user specific profiles over time. In the situation in which the controller is integrated into the interconnect cable, the user specific profiles can be used over again with multiple battery pack power supply units.

The controller may also function to halt charging when a predetermined secondary battery voltage or current is reached or during particular electronic device operating modes. With respect to the current, the controller may halt charging when there is zero current to the electronic device or the secondary battery. In essence, in this case the controller may put the battery pack power supply into sleep mode. As previously noted, the battery pack power supply may be capable of charging the secondary battery while supporting operation of the electronic device. However, in certain electronic device operating modes it may be more efficient to suspend the charging of the secondary battery momentarily. To achieve this method, the controller may operate through the interconnection cable and provide communication signals to the electronic device so that the electronic device will disconnect the secondary battery. For example, the controller may suspend charging during peak load situations (e.g., when a call is being placed or received) to allow more power to the load. As such the controller would indicate that the secondary battery is to be disconnected when the high load occurs.

Further, as indicated earlier, to save charge capacity, the controller may limit current out of the battery pack power supply. For example, the controller may the input current from the battery cells to the boost converter and thereby control the input current of the voltage converter. In one variation of the invention, the controller may current-limit at times other than during startup interval, for example by using a timer, to ensure that the electronic device has sufficient power for startup, because some electronic devices require more current during a startup mode. The controller may also be instructed by the electronic device to stop the current limiting for short intervals as required by other high current modes of the electronic device, allowing for time-limited withdrawal during those periods too. As indicated above, the controller will attempt to limit the current under most operating modes because quick high - current depletion may result in loss of some energy due to moisture migration in the battery cell. It is wasteful to discharge the cell too fast. However, shorter time periods of high current do not cause serious moisture migration. The controller may also control the value of boost voltage output by the boost voltage control circuit.

The battery pack power supply may further include a status indicator. The status indicator may provide, for example, an indication of whether the battery pack power supply is in use, the amount of charge remaining in the battery pack, the number of charges of a secondary battery remaining, the percentage of the secondary battery charging capacity still available, and/or the number of electronic device operation hours remaining (e.g., talk / standby time). In one embodiment the indicator may be, for example, a lamp or series of lamps which indicate supplying power (e.g., charging) status of the battery pack power supply. For example, an LED could be turned on when the battery pack power supply is discharging current, or a group of LEDs could be turned on at various levels of current discharge. Further, a power sensitive strip may be included which, when connected to the terminals, indicates the amount of charge remaining by a change in color of the strip (similar to power sensing strips attached to the side of alkaline battery cells). This power sensitive strip may be attached to the side of the battery pack power supply case and activated by pressing it to the side of the case. In another embodiment, a alpha-numeric display may be provided for displaying information as to the use status of the battery pack power supply, the amount of residual charge remaining in the battery pack power supply for charging the secondary battery and/or operation of an electronic appliance. For example, the display may indicate that the battery pack power display is charging, not charging, completed charging, and/or depleted. The display may further provide information about the present power capacity of the secondary battery when the battery pack power supply interconnect is connected to the electronic appliance. The alphanumeric display may be, for example, an LCD.

The battery pack power supply may be provided with a storage or travel case that seals the battery pack power supply to protect it from the ambient environment and minimize the exchange of gases, thereby extending shelf life. This is important for metal-air batteries because their electrolyte may evaporate and the cells become dehydrated which reduces the energy capacity of the cells before they are completely discharged. The storage or travel case may be integral with the battery pack power supply case or may be a separate case and may provide a pseudo hermetic or hermetic seal for the battery pack power supply case. Therefore, the storage or travel case will help preserve the battery moisture independent of the ambient environment so that the battery cell shelf life and efficiency remains optimal.

In one variation of the invention the storage or travel case may be a slipcover integrally configured with the battery pack power supply case and the connection configuration. In this embodiment the slipcover may be made of a rigid plastic similar to that of the battery pack power supply and the battery pack power supply may slide into the slip cover connector end first. The side of the battery pack power supply opposite the connector will provide on end of the hermetically sealed case with the slip cover providing the other seven sides to create a sealed box in which the battery pack power supply case remains when not in use. Metal-air batteries must have oxygen to operate and therefore by designing the slip cover so that the battery pack power supply must be completely remover before an interconnection cable can be attached, it can be ensured that it will not be connected up to an electronic device without having air available for operation. In another variation, the storage case may be integral with the battery pack power supply case and have the battery cell housing mounted within the storage case. For example, the integral battery pack power supply housing and storage case may be made of two half pieces hinged together on one side in a "clam shell" type package arrangement so that it can be opened and closed. The case may be spring loaded so that each half is spring urged inward so that the case remains closed unless the user opens it. Or, the case may have a latch mechanism for keeping the clam shell case closed unless opened. Each half may house one or more battery cells. If the battery cells are metal-air batteries the air holes of the battery cells and related air holes in the casing are facing inward when the battery pack power supply housing and storage case is closed. When the battery pack power supply housing and storage case is closed the two halves with air holes are facing inward at each other and an outer rim of each half are in contact so that the storage case is sealed. On opening the case, the two halves pivot on the hinged end and the case separates in a butterfly arrangement. The case may open only partially; for example, such that the two halves are at an angle of say 30 degrees and the air holes are still generally facing one another and exposed to the ambient air. In this manner a connector for the interconnect wire may occupy the gap in the opened end of the clam shell case arrangement. Alternatively, the case may open to some wider angle, as much as close to 360 degrees and the two halves may then be in contact back-to back such that the air holes are facing opposite directions and completely open to the ambient air. In any case, the connector interface may be configured in the hinged side of the case or integral to one of the other sides.

In preferred embodiments, the connector interface is configured so that it may only be used when the case is open and ambient air can get to the air access holes. As such, the connector interface may include a mechanical interfering element to prevent the interconnect cable from being connected when the case is closed to preserve power and ensure that the battery pack power supply is not required to provide power when the case is closed. In one embodiment, connection of the interconnection cable adapter to the connection interface would spread the two halves of the clam shell case sufficient for operation of the battery pack power supply. In any case, the air access holes are open to the ambient environment when the case is open and sealed from the ambient environment when the case is closed. The storage and travel case may also include a hydrogen release valve to allow egress of incidental hydrogen released from the metal-air battery cells while they are enclosed in the case. Further, the storage case may be as simple as a plastic pouch with a seal, e.g., a zip lock bag.

The battery pack power supply may have various convenient configurations for integration of the battery pack power supply with the electronic appliance it is supporting, the storage case, the voltage booster, the controller, and/or the interconnect cord. In one embodiment, the electrical adapter may be integral to the battery pack power supply case and the case may be physically attached onto the electronic appliance, thus, making an inter connection without a cord. The physical attachment may be, for example, a clip, snap, Nelcro, or adhesive strip. As discussed earlier, communication between the controller of the battery pack power supply and the electronic appliance may be through the same connection as the power is supplied. In one variation, if an inter connection cable is used to connect the battery pack power supply to the electronic appliance, the inter connection cable may be retained in the battery pack power supply case or the storage case on an integrate spool or coil. The spool or coil may be spring-loaded for easy retraction and rewinding of the cable. In another variation, a residual capacity meter may be integral to the battery pack power supply case or the storage case. In a still further variation, a multi-headed adapter inter connection cable including a controller may be provided to connect two or more battery pack power supplies to an electrical appliance. The controller may be programmed to finishes drawing power from one of the battery pack power supply until it is substantially depleted before drawing power from another battery pack power supply connected to the controller. The controller also might discharge two or more battery pack power supplies simultaneously. In this way, two or more battery pack power supplies may be used with the same controller for longer use without the need to manually monitor the power available in a particular battery pack power supply.

In a still further variation, the battery pack power supply may include a low power transceiver and antenna connected to a smart controller to provide wireless communications with electronic appliances. When the battery pack power supply is passed with in a few feet of the electronic appliance a compatibility notice may be provided to the user. This compatibility notice may be provided by one or more LEDs, a noise or vibration, or an alphanumeric display.

As indicated above, the portable battery pack power supply describe herein may be used to power a variety of different portable electronic devices such as PDA's, wireless communication devices such as telephones, etc., which may have a variety of different connectors, different battery pack dimensions, and different voltage, current and power requirements.

The invention will be described in connection with certain preferred embodiments, with reference to the following illustrative figures so that it may be more fully understood.

With reference to the figures, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in provide what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Brief Description of the Drawings

FIG. 1 is a front view of one embodiment of a battery pack power supply, according to the present invention.

FIG. 2 is a view of one embodiment of a battery pack power supply shown in FIG. 1, according to the present invention.

FIG. 3 is a cross sectional of one embodiment of a battery pack power supply shown in FIG. 1, according to the present invention.

FIG. 4 is a perspective view a prismatic metal-air battery cell used in one embodiment of the battery pack power supply according to the present invention. FIG. 5 is a front cross section view of one embodiment of a battery pack power supply shown in FIG. 1, according to the present invention.

FIG. 6 is a further cross sectional view of one embodiment of a battery pack power supply shown in FIG. 1 illustrating a moisture inhibiting means for the battery cells, according to the present invention. FIG. 7 is a perspective view of one embodiment of a battery pack power supply connected to an inter connection cable having integral adapters and a booster, according to the present invention.

FIG. 8 is a circuit diagram illustrating one embodiment of a power booster used with the battery pack power supply, according to the present invention. FIG. 9 is a circuit diagram illustrating one embodiment of a power booster, smart controller, and indicator LEDs used with the battery pack power supply, according to the present invention.

FIG. 10 is a perspective view of another embodiment of the battery pack power supply inter connection cable having integral adapters, booster, and controller, with the electrical appliance adapter having a universal connector, according to the present invention.

FIG. 11 is a perspective view of another embodiment of the battery pack power supply including a storage or travel case, according to the present invention.

FIG. 12 is a cross sectional view of the battery pack power supply in the storage or travel case, according to the present invention. FIG. 13 is a perspective view of one embodiment of an integrated battery pack power supply and a storage or travel case, according to the present invention.

FIG. 14 is a perspective view of another embodiment of an integrated battery pack power supply and a storage or travel case, according to the present invention.

Detailed Description of the Illustrated Embodiments

The general aspects of designing highly efficient compact metal-air battery packs are at the heart of the present invention. These general aspects are explained in detail in U.S. Patent Applications Serial Numbers 60/112,292, filed on December 15, 1998; 60/119,563, filed February 10, 1999; 60/119,568, filed February 10, 1999; 09/293,927, filed April 15, 1999; and 60/135,061, filed May 20, 1999, which are hereby incorporated by reference for all purposes. The reader is referred thereto for a detailed background of each of these general aspects including packaging considerations, air flow in the operation of metal-air batteries, water repulsion methods, electrolyte retention, etc., necessary for designing a metal-air battery pack useful for consumer use. The present invention is particularly well suited for metal-air batteries and is directed to a versatile universal battery pack power supply particularly useful as a portable charger and supplemental power source for a variety of portable electronic devices.

According to the present invention, a versatile universal battery pack power supply device is provided which includes one or more high current density batteries, for example metal-air primary battery (i.e., disposable) cell(s), capable both of powering a high power electric device during operation and providing secondary battery charging for such devices. Such electric devices may include, for example, a personal digital assistant (PDA), a wireless communication device such as a wireless telephone or two-way pager, a laptop computer, a wireless multifunctional device, hand tools, etc. The battery pack power supply is particularly useful for portable hand held electronic devices and may have sufficient current capacity to support the use of such a portable electronic device in all modes of operation. The battery pack power supply may further have sufficient charge capacity to charge the secondary battery of the portable electronic device one or more times. The battery pack power supply may also have sufficient current capacity to power the continued operation of the portable electronic device while charging the secondary battery of the portable electronic device (one or more times).

The battery pack power supply has various physical characteristics that make it well suited to act as a supplemental portable power source. The battery pack power supply is preferably designed to be small in size so that it may be carried easily by a person on the go. For example, when intended for use with portable electronic devices, the battery pack power supply may be small enough to fit in a shirt pocket and/or small enough to fit comfortably in the palm of a person's hand. The battery pack power supply is preferably lightweight so that it can be easily carried during travel. For example, a small lightweight battery pack can be created by including fewer battery cells (e.g., metal-air battery cells) than would be needed to meet the voltage requirements of the portable electronic device. In this case, the battery pack power supply could, for example, be equipped with a voltage boost circuit which will step-up the voltage from the battery cell voltage to the portable electronic device's recommended voltage level. Further, the battery pack voltage supply may be connected to the portable electronic device with a connection wire so that the battery pack can be carried in a person's pocket or purse, rather than the battery pack case being physically attached to the portable electronic device, and supply power to the portable electronic device and its secondary battery. This convenient packaging is particularly useful when using the portable battery pack power supply to power and/or charge the secondary power supply of, for example a wireless telephone or PDA, when the mobile device is in use.

Referring to Figures 1-8, a few preferred embodiments of the battery pack power supply will now be explained. Fig. 1 is a front view of one embodiment of a battery pack power supply. In general, the portable battery pack power supply may include a battery pack case 100 for housing one or more high current battery cells and an electric interconnect (see Fig. 7, item 700) which enables the battery pack to power the portable electronic device remotely. The battery pack case 100 is preferably made of a durable lightweight water-resistant material, such as plastic. If the battery pack includes battery cells such as metal-air batteries that require air to operate, then the battery pack case will also include one or more air access holes 405. The air access holes are provided in sufficient number and size to ensure adequate airflow for the operation of the metal-air batteries. Preferably, the number and size of holes is sufficient to ensure adequate air flow even when some of the air access holes are blocked during use of the battery pack. One or more standoffs or posts 110 may also be included on the case outer surface to further ensure there is minimal air flow access hole blockage when the battery pack case is set on a flat or semi-flat surface. The standoffs may are shown as posts but may be any type of structure sufficient to support the case on a flat or semi-flat surface so that most of the air holes are open to the ambient environment. Further, the case may include valleys or ridges 115 or other geometry which assist in repelling liquids that might be spilled on the battery pack case. The battery pack case may also include an electrical connector socket 120 (see Fig. 1-3) for connecting an electrical inter-connection cord.

Referring now to Fig. 3, the portable battery pack power supply may include one or more battery cells 310A - 310D of any physical shape, for example round, cylindrical, prismatic, etc. However, the battery cells should be of a physical shape which can provide the greatest charge packing density so that the power and current capacity required of high power devices can be packed into as small a physical space as possible. In this way, a powerful power source can be provided in the smallest size and most lightweight package as possible. In one preferred embodiment, the battery cells 310A - 310 D are made in a prismatic shape and are metal-air batteries so as to maximize the current density and current capacity in the smallest volume possible, and thus achieve high packing density.

The battery pack case 100 is also preferably designed so that there is a distance between the air ingress surface 404 of the metal-air battery 310 and the battery pack case 100 to ensure adequate ingress of air for operating the metal-air batteries. For full battery operation and high energy efficiency there must be sufficient air ingress through the air access holes 405 in the battery pack case 100 and similar air access holes in one electrode 404 of the metal-air batteries 310A - 310D. This is provided in part by having a small channel space 305, for example 2 millimeters to a fraction of a millimeter in width, between the inside surface 300 of the battery pack case 100 and the air inlet surface 404 of the metal-air battery cell 310. For example, the case may have a slightly curved or concave inner surface 300 (and therefore a slightly convex outer surface 301) opposite the air-ingress surface 404 of the metal-air battery 310. The slightly convex shape of the outer surface 301 of the battery pack case 100 also may ensure that a limited number of the air ingress holes get blocked at one time. Of course, the battery pack case surrounding surfaces 301 does not need to be curved but may be flat with the same width channel 305 from the battery cell 310A - 310B throughout the battery pack case 100. Details as to the necessary dimension standoff between the battery pack case 100 and the battery cells 310 to ensure adequate air transfer for the battery pack case 100 can be found in U. S. Patent Application Ser. No. 09/293,987 entitled "Battery Pack Design for Metal Air Batteries, filed 4/15/1999, the entirety of which is hereby incorporated herein by reference as if fully set forth herein. As discussed in more detail, the channel space 305 may include an air permeable and liquid inhibiting material to reduce liquid ingress and egress from the battery cells while ensuring air exchange.

The portable battery pack power supply case 100 may be made in any convenient geometrical shape, e.g., a disk, an elongated rectangle cube (stick shape), a square cube, two circles connected to a central axis, a clover leaf, etc., which would be comfortable for the user and useful in housing the battery cells. The shape depends on the shape of the cells and their arrangement, which are preferably such as to maximize packing density consistent with gas exchange requirements.

Referring now to FIG. 4, a prismatic metal-air battery cell 310, for example a zinc-air battery cell, useful for the portable battery pack power supply of the present invention is illustrated and will now be explained in some detail. Each metal-air battery cell 310 may be, and preferably is, a prismatic metal-air battery cell as shown in FIG. 4, to permit high packing density.

In one embodiment, each metal-air battery cell 310 is box-shaped with rounded corners. The rectangular shape permits high packing density where an array of battery cells is required to achieve desired current and voltage. The battery cell case 402 holds the various elements of an electrochemical battery cell. The battery cell 310 has an outer case wall 402 that may be of plastic or metal. The outer case wall 402 is supplied with air access holes 405 on at least one surface to allow oxygen to enter the battery cell 310. The battery cell 310 may absorb oxygen on one of its major planar surfaces, for example the gas-exchange wall 404, and that side alone would then be supplied with holes. Other battery cell designs that absorb oxygen through multiple sides are also possible (herein after referred to as "bicells").

In general, oxygen access holes 405 must allow sufficient oxygen to reach the air cathode to satisfy the electrochemical requirements of the battery cell 310 in the given application. If the holes 405 are too large or plentiful, excessive amounts of moisture will be lost from the battery cell 310 shortening the standby or shelf life of the battery cell 310.

If the holes 405 are too sparse, the battery cell 310 may not satisfy the electric load.

For example, a typical analog cellular phone, when in "talk" mode, may draw between 400-700 mA of current, depending in part on the distance between the phone and the transmitting antenna and the surrounding atmospheric conditions. Likewise, a typical digital cellular phone may draw between 200 - 450 mA of current. As depicted in FIG. 3 and 6, one battery pack configuration may contain four metal air battery cells 310, for example zinc-air battery cells. These battery cells 310 require oxygen at the rate of approximately 0.15 cc/sec to generate approximately 600 mA of current and approximately 0.05 cc/sec of oxygen to generate approximately 200 mA of current.

To ensure adequate oxygen delivery to the air cathode of the metal-air battery cell 310, air access holes 405 are distributed across the gas-exchange wall 404 (air ingress wall) of the case wall 402 of the battery cell 310. The air access holes 405 on the gas-exchange wall 404 of each metal-air battery cell 310 are sized and populated to ensure that the cathode, under high current load, is not starved for oxygen, which would result in a drop in voltage. In addition to insuring an adequate supply of oxygen to the cathode, the number and spacing of the holes 405 are also designed to minimize excessive moisture loss. As discussed above, a difference in partial pressure of oxygen across the air access holes 405 forces air to diffuse through the air access holes 405. ^' A difference in partial pressure of oxygen across the air access holes 405 results from the depletion of oxygen inside the battery cell 310 when the oxygen is converted to hydroxyl ions. This generates a gradient that causes oxygen to diffuse into the battery cell case 402. The density of the holes 405 may be optimized by bringing a limited number of holes 405, say two, closer and closer from a remote separation until the total current generated by the metal-air battery cell 310 starts to drop off significantly. This indicates the point where the area supplied by the air access holes 405 begins to overlap significantly. A more dense spacing simply provides area for evaporation without contributing substantially to oxygen supply to the cathode.

One metal-air battery 310, a zinc-air battery cell, with an area of approximately 2.5 cm x 4.5 cm and a thickness of 0.5 cm has been determined to be a flexible size for a variety of practical battery pack sizes and shapes, which provides a suitable power for a large range of cellular phones, PDAs, and other electronic devices. For ease of manufacturing, it has been found desirable to employ holes 405 of around 0.4 to 0.5 mm in diameter because such holes 405 can be punched conveniently (without high rates of wear of the punching tool) in battery cells 310 of 0.1-0.4 mm case wall 402 thickness and provide good air access while, at the same time, limiting moisture loss. A zinc-air battery cell 310 with an area of approximately 2.5 cm x 4.5 cm should have approximately 70 such holes 405 on the gas-exchange wall 404 of the battery cell 310.

Each metal-air battery cell 310 under substantial current load and/or after a degree of discharge may provide between 0.9 and 1.2 volts. In a PDA requiring four zinc-air battery cells 310 the battery pack may have a combined air-electrode surface area of about 30-60 cm². The air access openings in the case wall on the gas-exchange wall of the metal-air battery cells have a total area of at least 0.2 cm², preferably at least 0.5 cm².

In the embodiment shown in Figs. 1-7, the battery case 100 is a generally cubic in shape and houses four battery cells 310A - 310D, each of a prismatic shape. Referring to Fig. 5, a first pair of cells 310A and 310B are arranged side-by-side along a longer dimension 505 and 506 and another two cells 310C and 310D having the same side-by-side arrangement are placed back to back with the first two cells 310A and 310B. (See Figs. 2 and 6.) In another preferred embodiment (not shown), the case has a higher aspect ratio (stick shape) by lining up the shorter dimensions 510 and 511 of each pair of cells in the same back to back configuration. In a still further embodiment the air inlet holes surface 404 of the battery cells are facing one another and the battery pack case is configured as a clam shell which opens at least wide enough to ensure adequate air ingress (discussed in more detail below).

The portable battery pack power supply also may include a means for arranging and retaining the one or more battery cells 310 housed within the battery pack case 100. The means for arranging and retaining the battery cells may be a receptacle 315, partial walls, or posts sufficient to hold the battery cell(s) in predetermined locations and may be separate or integral to the battery pack case. As illustrated in Figures 3, 5 and 6, a plastic frames may be used to house the battery cells 310A - 310B in the battery pack case.

Referring to Fig. 6, the battery pack case 100 may house a moisture barrier material 605 which, as illustrated in this embodiment, is a hydrophobic layer formed across the openings in the plastic frame 315. This material provides a barrier to water to keep water from entering the battery cell 310 and helps retain any electrolyte that may leak from the battery cells 310 trough the air ingress holes 404, while allowing air ingress. The water barrier material 605 may be made of, for example, Teflon, polypropylene, or PTFE. Further, non-absorbent paper of an absorbent material 610 may be placed between the battery cell(s) 310 air ingress surface 404 and the moisture barrier 605 to absorb possible leaking electrolyte. The absorbent material may be, for example, paper similar to the paper used in paper towels (e.g., Bounty™) or used in sanitary napkins for women (e.g., CoForm™ of Melt-Blown™). Although the moisture barrier 605 and absorbent material 610 are shown in this embodiment as being integral with the plastic frame 315 holding the battery cells 310, one would understand that they may be separate from the frame 315 or means for arranging and retaining the battery cell(s) 310. In one variation, the moisture barrier may be, for example, a polypropylene or Teflon™ envelope or bag that surrounds the housing and metal air battery cells. In another variation, the moisture barrier may be, for example, a poly propylene film place over an opening in the metal air battery cell housing with a highly absorbent material such as CoForm™ may be used between the cells and the plastic frame 315 and/or the battery pack case 100 openings (i.e., in channel space 305). An electrical interconnect enables electrical connection of the battery pack power supply 100 to a portable electronic device, for example a personal digital assistant or a wireless communication device, so that the battery pack case 100 may be physically remote from the portable electronic device case while providing power to the portable electronic device. This allows the user to place part of the weight of the combined appliance where it is borne more easily. For example, the added weight of an auxiliary battery in a hand-held cell phone could become onerous, so the charger/auxiliary battery may be placed in a shoulder bag or pocketbook or hooked on a belt, etc. The interconnect may include, for example, a cable 700 with connectors 705 and 710 on either end. One electrical connector 705 will connect the cable 700 to the portable battery pack power supply 100 via the connection port 120 and another connector 710 will connect to the portable electronic device. To simplify interconnection with a minimum of fumbling, the cable ends are preferably of different shapes and/or sizes to ensure that the respective ends are not easily transposed. One or both connectors are preferably of symmetrical design so that proper electrical connection is insured, regardless of orientation. In one preferred embodiment, the connector 705 and respective connection port 120 for the battery pack power supply 100 is bilaterally symmetrical so that, when used, it closes the circuit connections to provide a battery pack power supply in which two or more batteries cells are connected in parallel. For example, referring to Fig. 2, the connector has three electrodes, electrode 210 in the middle is a common electrode for the two sets of batteries 310A - 310B, and electrodes 205 and 215 are the opposite polarity poles to the common electrode 210 for each of a respective battery pair, 310A and 310B or 310C and 310D. In this way, the battery cells 310 to be connected in parallel will not experience a slow parasitic discharge caused by slight differences in potential of the cells and will only be connected in parallel when the battery pack power supply 100 is connected to the load. Of course, the cable 700 could be connected to the battery pack case via a permanently affixed pigtail secured to the battery pack case 100. The cable 700 may include a voltage converter 800 and/or controller 900. As discussed in more detail below, the voltage converter 800 / controller 900 may provide battery pack power supply 100 operation status via one or more indicator lights 925A and 925B indicating, for example, charging, off, fully discharged, etc. The converter 800 / controller 900 might also include a voltage level control 930.

In a further variation, the cable 700 may be retained in the battery pack case 100 or on the end of the battery pack case 100, and may be wound on a spool for compact storage and quick retrieval. For maximum versatility a universal connector 1010 may be used for connecting to a plurality of different types of portable electronic devices (see Fig. 10).

The portable battery pack power supply 100 may further include a voltage booster and/or a controller. Referring to Fig. 8, one exemplary voltage booster is illustrated with circuit 800. This voltage booster may be used to convert the output voltage of the battery cells 310 from, for example, 4 volts of the battery pack power supply to 5 volts needed for the electronic device. Further, the voltage booster 800 may be capable of limiting the input current while efficiently supplying power.

The voltage booster may include a voltage controller switching circuit 805 for switching an input voltage from the battery cells 310 through an inductor L, a diode Dl, and a capacitor Co connected in series. As such, the inductor L and capacitor Co are charged and discharged using a switching transistor, for example, Q801 based on feedback from Nout. In operation, the voltage boost circuit 800 will boost the combined voltage of the battery cell(s) 310 to the desired/required voltage for operating the portable electronic device and/or charging a secondary battery by switching Q801 on and off based on the output voltage. Further, the voltage booster circuit 800 may include a current limiting feature to limit the current drain from the battery cells 310, and during current limiting the output voltage may drop below the desired voltage level.

Controlling the discharge current (discharge current limiting) is important so as to ensure the battery cells in the battery pack are not discharged too quickly. Discharging batteries too quickly may thereby reduce the maximum power available from the battery.

This is particularly true for metal-air batteries, which can experience asymmetry in the chemical reaction of air in the battery cells creating moisture migration such that a portion of the reactive electrode is not fully utilized during discharge.

One exemplary circuit for current limiting may include an oscillator that has reduced on-time if the current drain from the battery cells exceeds a particular level as determined by the voltage across a predetermined resistance. As illustrated in Fig. 8, the predetermined resistance includes resistors Rl and R2 connected between the battery pack supply voltage Nin and the current peak sense terminal 7, Ipk, to an oscillator 910. The value of resistors Rl and R2 are selected so that the when the current reaches the peak acceptable level that the voltage across the series resistance results in a voltage differential between input terminal 6, V<χ, and input terminal 7, Ipk, at a trigger level and any voltage at that level and higher will start reducing the turn on time of transistor Q801 to thereby reduce the output voltage Nout and the related input and output currents. Further, the resistance of Rl may be selected to be relatively small so that the efficiency of the voltage conversion is maximized. For example, if the switching circuit 805 is a Motorola™ MC34053 having trigger voltage of 0.3 volts between the input terminals 6 and 7 for current limiting, then Rl might be selected to be 0.22 ohms to have good efficiency and R2 might be selected to be 12 ohms, then the voltage booster will become current limited when the voltage across Rl is 0.1 volt and across R2 is 0.2 volts. In this manner, the input current from the battery cells 310 may be limited to approximately 0.5 amperes and the output voltage of the voltage booster circuit 800 will drop off from its desired operating level, say 5.0 volts, when this maximum current level is exceeded, so as to not damage the metal-air battery cells with excessive current drain beyond their capability. Thus, the controller 900 may control the current drawn from the battery pack power supply 100 by controlling the current from the supply side.

In another embodiment, a controller 900, which may include the voltage booster 800, may be provided with the battery pack power supply 100, as illustrated in Fig. 9. The controller may provide various features/functions including voltage boost and regulation, input current limiting, compatibility indicator, battery pack power supply timeout, charge status indication, and electronic device intercommunication control. For example, the controller 900 may include a voltage booster with current limiting similar to the voltage booster illustrated in Fig. 8, including a switching circuit 805, resistors Rl and R2, inductor LI, diode Dl, and capacitors C9-C11. Further, the controller 900 may include a battery pack power supply timeout having a counter 910 which starts counting time from a point in time when an input voltage is applied to the + battery and - battery tenninals, for example when the interconnection cable 700 is comiected to the battery pack power supply the RST terminal of the counter 910 goes high and the counter begins to count time. In this case, after a predetermined time interval, for example 2 hours, the output Q14 of counter 910 goes high and transistor Ql turns on. As a result, the Comp input of the switching circuit 805 is taken to VCC and the voltage booster stops boosting the output voltage Nout. Of course, one skilled in the art would recognize that the start time for the counter 910 could be triggered by connecting an electronic device to the output terminals -rNout and -Vout using various current or voltage sensing schemes.

In addition, the controller 900 may include a compatibility indicator. The compatibility indicator may include a counter 915 which is started when an input voltage is applied to the + battery and - battery terminals, for example when the interconnection cable 700 is connected to the battery pack power supply. In this case the signal is supplied by counter 910 triggered off a power up RST going high. To prove compatibility, some electronic devices that are connected to the battery pack power supply 100 may look for a particular current. If the controller 900 also contains input current limiting which is less then the current needed to indicate compatibility with the electronic device to be supported, then a compatibility counter 915 and associated circuitry will be included to disable the current limiting circuit for a predetermined period of time. In this case an output 3 of the counter 915 is taken high at power on and turns on transistor Q5, which turns on transistor Q2. Transistor Q2 shorts out resistor R2 and disables the current limiting so that the input current from the battery cells may reach the current required by the electronic device, for example 1.5 amperes rather than the 0.5 amperes current limit. After counter 915 times out, for example after a 25 - 30 seconds period in which the electronic device confirms compatibility, the counter 915 output 3 goes low turning off transistor Q2, putting the voltage boost back into normal current limiting of around, for example, 0.5 amperes.

The controller 900 may also include one or more status indicators 925, for example light emitting diodes D5 and D6 (LEDs) for indicating one or more types of status of the battery pack power supply 100. The LEDs may be different colors, for example, on may be red (D5) and one may be green (D6). In the embodiment shown in Fig. 9, D6, a green LED, may indicate that the battery pack power supply 100 is on and, for example, powering the load, and electronic device. In this case, green LED D6 would be on when the counter 910 was timing out. Further, the red LED D5 will be on when the counter 910 has timed out and shut the voltage converter off. As will be discussed in more detail below, the status and operating mode indicators may take forms other than LEDs.

The controller 900 may further include a control input for communicating with the electronic appliance as to when charging is to start and/or stop. In the embodiment shown in Fig. 9, a control signal line of the electronic device to be charged is attached to control input 930. If a high voltage level is input to the control terminal 930 by the electronic device, transistor Ql is turned on and the COMP (5) input of the switching circuit 805 is taken high to + Batt. As a result, the voltage booster stops boosting the output voltage, Nout. If the battery pack power supply 100 was being used to charge the secondary battery of the electronic device, charging stops.

As illustrated in Figs. 7 and 10, the voltage booster 800 and/or controller 900 may be included inline with the interconnect cable. In another variation the voltage booster 800 and/or controller 900 may be incorporated into the battery pack case or constructed with a connector so as to be detachable from the battery pack unit.

In one variation of the invention, the controller 900 may be a "smart" controller with various microprocessor type functions capable of controlling charging to prevent wasting battery pack power supply energy and overcharging the secondary battery. For example, the controller 900 may include a timer which automatically turns off the charging in a predetermined time frame based on various factors such as the type of battery being charged and the present capacity (level of charge) in the secondary battery. For example, this may be done as discussed in 09/641,016, which is hereby incorpored by reference as if fully set forth herein in its entirety: U.S. Patent Application Serial No. 09/641,016. The controller 900 may operate through the electric power wires of the inter connect cable 700 and simulate the appropriate handshake with the electronic device to determine the particular type of secondary battery connected to the electronic device, and thereby set the control parameters such as maximum current drain and voltage level accordingly. In another embodiment, the battery pack power supply may have an IR or RF port coupled to the controller for receiving secondary battery type information, software, and/or parameter updates from an electric appliance.

Further, the controller 900 may be configured to operate in a manner which would allow charging only when the capacity of secondary battery falls below a predetermined level. The trigger level for charging may be selectable by the user. The controller 900 may monitor the residual capacity of secondary battery and may recharge the secondary battery with the battery pack power supply 100 only when a user-selected threshold indicative of the percent of depletion desired is reached. Thus, a user may select and set the controller to accept recharging only when the charge of the secondary battery is below 70 percent if the user wants more efficiency out of the battery pack power supply. However, if the user is not as concerned about efficient use of the battery pack power supply 100 the user might select a recharge threshold of 95 percent to trigger the controller to activate recharge of the secondary battery. Further, the controller 900 may include a micro-controller and memory or a microprocessor that could be programmed to set a particular trigger threshold based on profile and user status. For example, the trigger level may be 80 percent for vacation, 90 percent for business, or 50 percent for home use, and the user may merely select at any given time whether they wish to operate the battery pack power supply 100 on the "vacation" profile, the "business" profile, or the "home" profile. These profiles may be customized and added to by the user. Standardized profiles of users that the buyer can select to use to optimize the charging of the secondary battery. The controller may be a more limited circuit for a "smart" controller with slightly less processing capabilities than a microprocessor. In either case, the controller 900 may have capabilities to provide prompts such as "Are you at home?" "Are you on the road?" and/or "Are you on vacation?" via an alphanumeric display. In one variation, the controller 900 may download profiles and profiling software from the Internet and set parameters on the smart controller or microprocessor using RF, IR or any other coupled connection. Further, the controller 900 may have processor capabilities that can learn from the user's actions over time using, for example, artificial intelligence. In this way, the controller 900 can create user specific profiles over time. In the situation in which the controller 900 is integrated into the inter connect cable 700, the user specific profiles can be stored in memory in the controller 900 and used over again with multiple battery pack power supply units 100.

The controller 900 may also function to halt charging when a predetermined secondary battery voltage or current is reached, or during particular electronic device operating modes. With respect to the current, the controller 900 may halt charging when there is zero current to the electronic device or the secondary battery. In essence, in this case the controller 900 may put the battery pack power supply 100 into a "sleep" mode. As previously noted, the battery pack power supply 100 may be capable of charging the secondary battery while supporting operation of the electronic device. However, in certain electronic device operating modes it may be more efficient to suspend the charging of the secondary battery momentarily. To achieve this method, the controller 900 may operate through the inter-connection cable 700 and provide communication signals to the electronic device so that the electronic device will disconnect the secondary battery. For example, the controller 900 may suspend charging during peak load situations (e.g., when a call is being placed or received) to allow more power to the load. As such the controller 900 would indicate that the secondary battery is to be disconnected when the high load occurs.

Further, as indicated earlier, to save charge capacity, the controller 900 may limit current out of the battery pack power supply. For example, the controller 900 may limit the input current from the battery cells to the boost converter and thereby control the input and output current of the voltage converter. In addition, in one variation of the invention the controller 900 may current-limit at times other than during startup interval, for example by using a timer, to ensure that the electronic device has sufficient power for startup, because some electronic devices require more current during a startup mode, i.e., varying the timing for timeout of counter 915 based on real time input from the electronic device. The controller 900 may also be instructed by the electronic device to stop the current limiting for short intervals as required by other high current modes of the electronic device, allowing for time-limited withdrawal during those periods too. As indicated above, the controller 900 will attempt to limit the current under most operating modes because quick high - current depletion may result in loss of some energy due to moisture migration in the battery cell. It is wasteful to discharge the cell too fast. However, shorter time periods of high current do not cause serious moisture migration. The controller 900 may also be configured to receive real time control for the value of boost voltage output by the boost voltage control circuit.

Fig. 10 illustrates another interconnection cable 700 including a voltage boost 800 and controller 900. The battery pack power supply 100 may further include one or more status/operation indicators. The status indicators may provide, for example, an indication of whether the battery pack power supply is in use, the amount of charge remaining in the battery pack, the number of charges of a secondary battery remaining, the percentage of the secondary battery charging capacity still available, and/or the number of electronic device operation hours remaining (e.g., talk / standby time). In one embodiment the indicator may be, for example, a lamp 1040 or series of lamps (925 shown in Fig. 7) which indicate the status of supplying power (e.g., charging) for the battery pack power supply 100. For example, the LED 1040 could be turned on when the battery pack power supply is discharging current, or a group of two or more LEDs forming a bar graph, could be turned on together at various levels of current discharge.

Further, another status indicator may provide information as to the energy still remaining in the battery pack power supply 100. For example, a power sensitive strip may be included which, when connected to the terminals, indicates the amount of charge remaining by a change in color of the strip (similar to power sensing strips attached to the side of alkaline battery cells). This power sensitive strip may be attached to the side of the battery pack power supply case 100 and activated by pressing it to the side of the case.

In a still further embodiment, an alpha-numeric display, 1030 or 1035, may be provided for displaying information as to the use status of the battery pack power supply 100, the amount of residual charge remaining in the battery pack power supply 100 for charging the secondary battery and/or operation of an electronic appliance, the amount of time remaining to achieve a full charge 1035, and/or the present voltage across the load (i.e., the electronic device being supplied power). Further, the display 1030 or 1035 may indicate that the battery pack power supply 100 is charging, not charging, completed charging, and/or depleted. The display 1030 may provide information about the present power capacity of the secondary battery when the battery pack power supply 100 inter connect cable 700 is connected to the electronic appliance. The alphanumeric display(s) 1030 and 1035 may be, for example, an LCD. The controller 900 may include user-input devices 1031 and 1036, for adjusting user-input variables such as the charge time and/or charge voltage. For example, the user-input devices may be buttons, turn dials, etc. In this case, the user can determine, for example, how long counter 910 will take to timeout.

Referring now to Figs. 11 - 14, a battery pack power supply with a storage or travel case according to another embodiment is illustrated. The battery pack power supply 100 may be provided with a storage or travel case (e.g., 1100; 100A and 100B) that isolates the battery pack power supply 100 from the ambient environment and minimizes the exchange of gases. Sealing the battery pack power supply 100 in such a case will help extending shelf life of the battery cells 310 by reducing exposure to humidity variations inherent in most ambient environments. This is important for metal-air batteries because their electrolyte may evaporate and the battery cells 310 may thereby become dehydrated and reduces the energy capacity of the battery cells 310 before they are completely discharged. Therefore, the storage or travel case will help preserve the battery cells 310 moisture independent of the ambient environment so that the battery cells 310 shelf life and efficiency remains optimal.

The storage or travel case may be integral with the battery pack power supply case 100 or may be a separate case. Further, the storage or travel case may provide a pseudo hermetically sealed or hermetically sealed container for the battery pack power supply case 100. In one variation of the invention shown in Figs. 11 and 12, a separate storage or travel case 1100 is designed as a slip cover which slides over the battery pack power supply case 100 and an integral connection configuration 120. In this embodiment the slip cover storage or travel case 1100 may be made of, for example, a rigid plastic similar to that of the battery pack power supply 100. Further, the battery pack power supply 100 may slide into the slip cover storage case 1100 with the connector 120 end first. The side of the battery pack power supply 100 opposite the connector (side 1210) may operate as one end of a hermetically sealed rectangular box shape case with the slip cover providing the other seven sides, creating a sealed box in which the battery pack power supply case 100 remains when not in use. Further, the open end 1105 of the slip cover storage and travel case 1100 may have a tapered surface 1215 which opens the slip cover open end 1105 wider when the battery pack power supply case 100 is push into the open end 1105 of the slip cover travel case 1100. The skip cover storage and travel case 1100 may also include a seal 1205 around the inside of the open end 1105 which is firmly held to the outside of the battery pack power supply case 100 when the battery pack power supply case 100 is inserted into the slip cover storage and travel case 1100. The seal 1205 may be an O-ring or any other type of gasket made of, for example, a rubber material, which can provide a reasonably good seal so that air access holes in the surface 300 is not appreciably affected by the ambient environment humidity. As previously noted, metal-air batteries must have oxygen to operate. Therefore, by designing the slip cover storage and travel case 1100 so that the battery pack power supply 100 must be completely removed before an interconnection cable can be attached, it can be ensured that it will not be connected up to an electronic device without having air available for operation.

In one variation, the storage and travel case could be in two pieces and hinged on the enclosed end and may be spring loaded so as to remain closed around the battery pack power supply case 100. The open end may be modified to fully surround the battery pack power supply case 100. In this case, a seal may be around the lip of each half of the storage or travel case. Further, the storage and travel case may include a latch on the open end or the end opposite the hinge so as to securely fasten the storage and travel case closed. Another manner of creating an air tight seal could be to include a air inhibiting flexible material (e.g., rubber, plastic, composite with absorbing capabilities, etc.) to line the travel or storage case. This lining material may the engage with the air access holes surface 300 when the battery pack power supply case 100 is enclosed in the storage or travel case, thus performing the desired hermetic sealing (if a composite material is used the lining may also provide for electrolyte absorption. In another variation, the storage case may be integral with the battery pack power supply case and have the battery cell housing mounted within the storage case. Two examples of this variation are provided in FIGS. 13 and 14. Referring to Fig. 13, there is shown an integral battery pack power supply housing and storage case 1300 which may include two half pieces 100 A and 100B hinged together with hinge 1305 on one side and forming a "clam shell" type package arrangement. The hinge 1305 allows the two halves 100A and 100B to be opened and closed from one another at various angles 1320. The integral battery pack power supply case and storage case 1300 may be spring-loaded so that each half 100 A and 100B is spring urged inward to keep the case closed, unless the user opens it. Or, the integral battery pack power supply case and storage case 1300 may have a latch mechanism for keeping the clam shell case closed unless opened.

Each half 100A and 100B may house one or more battery cells 130. If the battery cells 130 are metal-air batteries, the air access holes of the battery cells and related air access holes in the case surface 300 face inward and opposite to one another when the battery pack power supply and integral storage case 1300 is closed. When the integral battery pack power supply and storage case 1300 is closed the two halves with air access holes are facing inward at each other and an outer rim of each half 100A and 100B may be in contact so that the storage case is sealed of semi-sealed. On opening the case, the two halves 100 A and 100B pivot on the hinged end and the case 1300 separates in a butterfly- winged manner. The case 1300 may open only partially, for example, such that the two halves 100 A and 100B are at an angle, for example 30 degrees, and the air access holes are generally facing one another. The angle selected may be set by a stop integrate in the hinge 1305 so as to ensure sufficient exposure so that ambient air is provided in sufficient amount to operate the metal-air batteries at peak efficiency and discharge. In this configuration, the stop may also align a set of openings in the hinge 1305 so that a connector for connecting the interconnect wire 700 may be connected to a gap in the opened end 1315 of the clam shell case arrangement. Alternatively, the case may open to some wider angle. For example 270 degrees so that it can sit with both halves 100A and 100B having their air access holes facing outward. In fact, the case and hinge of the integral battery pack power supply and storage case 1300 my open completely (as much as 360 degrees) and the two halves 100A and 100b may be placed back-to-back in contact with one another such that the air access holes are facing in completely opposite directions. In this configuration the metal air batteries 130 may be completely open to the ambient air. In any case, the connector interface may be configured in the hinged side of the case (1315) or integral to one of the other sides.

In preferred embodiments, the connector interface 120 is configured so that it may only be used when the case is open and ambient air can get to the air access holes. Two examples have been provided above. In such arrangements, the connector interface 120 may include a mechanical interfering element to prevent the interconnect cable 700 from being connected when the case is closed to preserve power and ensure that the battery pack power supply 100 is not required to provide power when the case is closed.

Referring to Fig. 14, another embodiment is provide which ensures the air access holes 105 are open to the ambient air when the intercom ection cable 700 is connected. In this embodiment, the connector interface is a third hinged member 1405 which is attached to the side of one of the halves (100B in this illustration) of the storage case. This hinged connector arm 1405 may have a stop/locking arm 1415 which is pushed out of the hinged connector arm 1405 when the hinged connector member is contacted with the other halve of the case (100A in this case). The stop/locking arm 1415 will keep the adapter connector 705 of interconnect cable 700 from being inserted into hinged connector arm 1405 until the hinged connector member 1405 is contacted to the second halve 100 A. Once released, the stop/locking arm 1415 can be push in place to lock the hinged connector arm 1405 in place to the second halve of the case 100A. In another embodiment, insertion of the interconnection cable adapter 705 to the connection arm or interface would spread the two spring loaded halves 100A and 100B of the clam shell case sufficient for operation of the battery pack power supply.

In any case, the air access holes are open to the ambient environment when the case is open and sealed from the ambient environment when the case is closed. As such, the storage and travel case may also include a hydrogen release valve to allow egress of incidental hydrogen released from the metal-air battery cells while they are enclosed in the case. Further, the storage case may be as simple as a plastic pouch with a seal, e.g., a zip lock bag.

The battery pack power supply 100 may have various convenient configurations for integration of the battery pack power supply 100 with the electronic device or appliance it is supporting, the storage case, the voltage booster, the controller, and/or the interconnect cord. In one embodiment, the electrical adapter may be integral to the battery pack power supply case 100 and the case may be physically attached onto the electronic appliance, thus, making an inter connection without a cord. In this embodiment the air access holes would be arranged on the sides of the battery pack power supply 100 which are not butted up against the electronic device it is connected to. The physical attachment may be, for example, a clip, snap, Nelcro, or adhesive strip. As discussed earlier, communication between the controller of the battery pack power supply 100 and the electronic device may be through the same connection (e.g., wiring, connector, etc.) as the power is supplied. In one variation, if an inter connection cable is used to connect the battery pack power supply to the electronic device, the inter com ection cable may be retained in the battery pack power supply case 100 or the storage case 1100 on an integrated spool or coil. The spool or coil may be spring-loaded for easy extraction and retraction and rewinding of the cable and convenient storage. In another variation, a residual capacity meter may be integral to the battery pack power supply case or the storage case. In a still further variation, a multi-headed adapter inter connection cable 700 including a controller 900 may be provided to connect two or more battery pack power supplies to an electrical appliance. The controller 900 may be programmed to continue drawing power from one of the battery pack power supply 100 until it is substantially depleted before drawing power from another battery pack power supply 100 connected to the controller. The controller 900 also might discharge two or more battery pack power supplies 100 simultaneously. In these ways, two or more battery pack power supplies 100 may be used with the same controller 900 for longer use without the need to manually monitor the power available in an particular battery pack power supply 100.

In a still further variation, the battery pack power supply 100 may include a low power transceiver and antenna connected to a smart controller, to provide wireless communications with electronic appliances. When the battery pack power supply is passed with in a few feet of the electronic appliance a compatibility notice may be provided to the user. This compatibility notice may be provided by one or more LEDs, a noise or vibration, or an alphanumeric display. As indicated above, the portable battery pack power supply 100 describe herein may be used to power a variety of different portable electronic devices such as PDA's, wireless communication devices such as telephones, etc., which may have a variety of different connectors, different battery pack dimensions, and different voltage, current and power requirements. Although particular embodiments of the present invention have been shown and described, it will be understood that it is not intended to limit the invention to the preferred embodiments and it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention. Thus, the invention is intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the invention.

All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes.

Claims

Claims:

1. A portable power adapter for delivering electrical power to a portable appliance, comprising: a current controller; an input adapter connectable to at least one electrochemical cell and an output adapter connectable to an appliance; a voltage controller connected between said input and output adapters to feed power from said input adapter to said output adapter and effective to raise or lower a voltage relative to a voltage of said at least one electrochemical cell; said current controller being connect and configured to control a current at said input adapter.

2. An adapter as in claim 1, wherein said current controller is configured to limit said current to a selected value.

3. An adapter as in claim 2, wherein said power adapter further comprises an interface for receiving an indication of a type of said at least one electrochemical cell and said current controller is configured to modify said selected value responsively to said type.

4. An adapter as in claim 1, further comprising a charging controller adapted to detect a mode of said portable appliance, said charging controller being adapted to detect at least two of a first mode in which said portable appliance is only charging a secondary battery connected thereto, a second mode in which said portable appliance is only in use, and a third mode in which said portable appliance is both charging and in use and to override said selected value responsively to said mode.

5. An adapter as in claim 2, wherein said input adapter and said current controller are configured to override said selected value when said appliance is in use.

6. An adapter as in claim 1, further comprising a switch configured to disconnect said at least one electrochemical cell responsively to at least one of a current or voltage threshold detected at said input adapter or output adapter.

7. An adapter as in claim 6, wherein said switch is configured to disconnect said at least one electrochemical cell when a charging current detected at said output adapter drops below a predetermined threshold.

8. A portable power adapter for delivering electrical power to a portable appliance, comprising: a current controller; an input adapter connectable to at least one electrochemical cell and an output adapter connectable to an appliance; a voltage controller connected between said input and output adapters to feed power from said input adapter to said output adapter and effective to raise a voltage relative to a voltage of said at least one electrochemical cell; said current controller being connect and configured to control a current at said input adapter to a selected value; at least one of said input and output adapters including an extension cord such that said at least one electrochemical cell may be located remote from said portable appliance.

9. An adapter as in claim 8, wherein said current controller is configured to selectively change said selected value.

10. An adapter as in claim 9, wherein said power adapter further comprises an interface for receiving an indication of a type of said at least one electrochemical cell and said current controller is configured to modify said selected value responsively to said type.

11. An adapter as in claim 8, further comprising a charging controller adapted to detect a mode of said portable appliance, said charging controller being adapted to detect at least two of a first mode in which said portable appliance is only charging a secondary battery connected thereto, a second mode in which said portable appliance is only in use, and a third mode in which said portable appliance is both charging and in use and to override said selected value responsively to said mode.

12. An adapter as in claim 9, wherein said input adapter and said current controller are configured to override said selected value when said appliance is in use.

13. An adapter as in claim 8, further comprising a switch configured to disconnect said at least one electrochemical cell responsively to at least one of a current or voltage threshold detected at said input adapter or output adapter.

14. An adapter as in claim 13, wherein said switch is configured to disconnect said at least one electrochemical cell when a charging current detected at said output adapter drops below a predetermined threshold.

15. A portable power supply, comprising: a replaceable primary battery pack; a corded adapter for connecting said battery pack to an appliance; a voltage controller for matching a voltage of said battery pack to said appliance; said battery pack having sufficient current capacity to permit said appliance to be used while connected for charging a secondary battery connected to said appliance.

16. A supply as in claim 15, wherein said battery pack has sufficient charge capacity to allow said secondary battery to be charged at least two times.

17. A supply as in claim 16, wherein said battery pack includes at least one metal air cell.

18. A supply as in claim 16, wherein said adapter cord is sufficiently long to permit said battery pack to be attached at the level of a waist of a user while said appliance is held at the level of a head of said user.

19. A supply as in claim 16, wherein said adapter includes an indicator of a residual charge on said battery pack.

20. A supply as in claim 16, wherein said voltage controller includes a voltage booster, whereby said battery pack may be reduced in size.

21. A supply as in claim 15, wherein said battery pack includes at least one metal air cell.

22. A supply as in claim 21, wherein said adapter cord is sufficiently long to permit said battery pack to be attached at the level of a waist of a user while said appliance is held at the level of a head of said user.

19. A supply as in claim 21, wherein said adapter includes an indicator of a residual charge on said battery pack.

20. A supply as in claim 21, wherein said voltage controller includes a voltage booster, whereby said battery pack may be reduced in size. 22. A supply as in claim 20, wherein said adapter cord is sufficiently long to permit said battery pack to be attached at the level of a waist of a user while said appliance is held at the level of a head of said user.

23. A supply as in claim 22, wherein said adapter includes an indicator of a residual charge on said battery pack.

24. A supply as in claim 15, wherein said voltage controller includes a voltage booster, whereby said battery pack may be reduced in size.

25. A supply as in claim 15, wherein said adapter includes an indicator of a residual charge on said battery pack.

26. A supply as in claim 15, wherein said voltage controller includes a voltage booster, whereby said battery pack may be reduced in size. ^■

27. An apparatus for selectably isolating a battery pack power supply from the surrounding environment comprising: a. a receptacle, b. a seal, and c. a battery pack power supply comprising: i) one or more metal-air batteries, and ii) a connector interface wherein said battery pack power supply may be reversibly introduced into the receptacle, such that when fully introduced: a. said seal contacts both the battery pack power supply and the receptacle, inhibiting gas flow between the battery pack power supply and the surrounding environment, and b. said connector interface is physically inaccessible from the surrounding environment.

28. The apparatus of claim 27, wherein one or more of said metal-air batteries are zinc-air batteries.

29. The apparatus of claim 27, wherein said seal is a rubber gasket.

30. The apparatus of claim 27, wherein said apparatus comprises a valve that can be operated to equalize the gas pressure between the battery pack power supply and the surrounding environment.

31. An apparatus for selectably isolating a battery pack power supply from the surrounding enviromnent comprising: a. a first element, b. a second element, c. a hinge connecting the first and second elements, d. a seal, and e. a battery pack power supply comprising: i) one or more metal-air batteries, and ii) a connector interface wherein: a. said battery pack power supply may be reversibly attached to either or both of said elements, b. said elements may be independently rotated about the hinge axis, such that when fully rotated towards one another into a first orientation: i) said seal simultaneously contacts each element, thereby encapsulating a volume, ii) said volume may include said battery pack power supply, such that gas flow is inhibited between said battery pack power supply and the surrounding environment, and iii) said connector interface in physically inaccessible from the surrounding environment, and c. in other orientations, said seal does not simultaneously contact both elements.

32. The apparatus of claim 31, wherein one or more of said metal-air batteries are zinc-air batteries.

33. The apparatus of claim 31, wherein said seal is a rubber gasket.

34. The apparatus of claim 31, wherein said apparatus comprises a spring, which inhibits rotation of said elements out of said first orientation.

35. The apparatus of claim 31, wherein said apparatus comprises a latch, such that reversibly engaging the latch inhibits rotation of said elements out of said first orientation.

36. The apparatus of claim 35, wherein said apparatus comprises a valve that can be operated to equalize the gas pressure between the battery pack power supply and the surrounding environment.

37. An apparatus for selectably isolating a battery pack power supply from the surrounding environment comprising: a. a first element, b. a second element, c. a hinge connecting the first and second elements, d. a connector interface, and e. a seal, wherein said elements may be independently rotated about the hinge axis, such that when fully rotated towards one another into a first orientation, said seal simultaneously contacts each element, thereby encapsulating a volume large enough to house a battery pack power supply, such that in said first orientation, gas flow is inhibited between said volume and the surrounding environment, and wherein in other orientations, said seal does not simultaneously contact both elements.

38. The apparatus of claim 37, wherein said connector interface comprises a reversible barrier, such that said barrier inhibits access to said connector interface in said first configuration, and said barrier permits access to said connector interface in said second configuration.

39. The apparatus of claim 37, wherein said barrier is stop/locking arm.