WO2010049773A2

WO2010049773A2 - Charging cable unit

Info

Publication number: WO2010049773A2
Application number: PCT/IB2009/007187
Authority: WO
Inventors: Tatsuya Mukai; Youji Minami; Satoru Ueno; Kiyoshi Goto; Shiro Mori; Hirotoshi Watanabe; Kouji Kakiuchi; Hiroshi Ooya; Tomoyoshi Hayashi; Yutaka Takada
Original assignee: Panasonic Electric Works Co., Ltd.
Priority date: 2008-10-28
Filing date: 2009-10-22
Publication date: 2010-05-06
Also published as: WO2010049773A3

Abstract

A charging cable unit includes a plug adapted to be detachably connected to a plug receptacle supplied with a commercial power and a plurality of cable connectors each of which is adapted to be detachably connected to a connector of an electric vehicle so that charging current is supplied to a battery of the electric vehicle connected via the connector. The charging cable unit further includes a selection unit, to which the cable connectors and the plug are connected via a charging cable, for selecting among the cable connectors one cable connector through which the charging current is supplied.

Description

CHARGING CABLE UNIT

Field of the Invention

The present invention relates to a charging cable unit for charging an electric vehicle.

Background of the Invention

Conventionally, a charging device for charging a battery mounted in an electric vehicle is provided (see, e.g., Patent Document 1) . In this charging device, a connector provided in a front end of the device is connected to a power receiving connector of an electric vehicle through a cable to charge the battery.

In the charging device disclosed in the above- mentioned Patent Document 1, there is provided only one cable to be connected to an electric vehicle. Therefore, when charging a plurality of electric vehicles, the cable has to be removed from an electric vehicle whose charging is finished, and then connected to a next electric vehicle, which is a time consuming operation. In addition, with this charging device, it has been difficult to charge more than one electric vehicle because charging is usually done during the night.

Fig. 22A shows an example of the charging cable unit AA. A cable connector G provided at one end of a cable 6 is connected to a connector of an electric vehicle, and a plug 3' provided at the other end of the cable 6 is inserted and connected to the socket BB of a commercial power source, so that a commercial power is supplied to the electric vehicle C to charge a secondary cell installed in the electric vehicle C. Fig. 22B shows the charging cable unit AA' provided with an electric leakage breaker 5' . When detecting an electric leakage, the earth leakage breaker 5' cuts off the power feeding to the electric vehicle C (see, e.g., Patent Document 2) .

With the charging cable unit AA' disclosed in Patent Document 2, an electric power can be supplied to charge the secondary cell of the electric vehicle C. However, an amount of power consumed for charging the electric vehicle C or the electricity cost cannot be checked and further an elapsed charging time, charging completion time, or the like cannot be displayed. Accordingly, a user has to directly check the charging cable unit to know whether charging is complete or not, thereby making it inconvenient.

Patent Document 1: Japanese Patent Laid-Open

Application No. H 5-328619 (Paragraph Nos . [0008] to [0010] , and Fig. 1) Patent Document 2: Japanese Patent Laid-Open

Application No. H 5-276674 (Paragraph Nos. [0012] to [0015] , and Fig. 1)

Summary of the Invention

In view of the above, the present invention provides a charging cable unit which improves working efficiency when charging a plurality of electric vehicles. Moreover, the present invention provides a charging cable unit with high flexibility which the user can find out the charging status of a secondary cell even at a location away from a charging place .

In accordance with a first aspect of the present invention, there is provided a charging cable unit including a plug adapted to be detachably connected to a plug receptacle supplied with a commercial power; a plurality of cable connectors each of which is adapted to be detachably connected to a connector of an electric vehicle so that charging current is supplied to a battery of the electric vehicle connected via the connector; and a selection unit to which the cable connectors and the plug are connected via a charging cable for selecting among—the cable connectors one cable connector through which the charging current is supplied.

Brief Description of the Drawings The objects and features of the present invention will become apparent from the following description of preferred embodiments, given in conjunction with the accompanying drawings, in which: Fig. 1 a schematic view of a system using a charging cable unit in accordance with a first embodiment;

Figs. 2A and 2B are circuit diagrams of a switching unit used for the charging cable units of the first to third embodiments ; Figs. 3A and 3B are perspective views of a cable connector used for the charging cable units of the first to third embodiments;

Fig. 4 is a schematic view of a system using a different charging cable unit in accordance with the first embodiment;

Fig. 5 is a schematic view of a system using a charging cable unit of a second embodiment;

Fig. 6A is a schematic view of a system using a charging cable unit of a third embodiment; Fig. 6B is a schematic view of a system using a different charging cable unit of the same embodiment;

Fig. 7 is a circuit diagram of a switching unit used for a charging cable unit of a fourth embodiment.

Fig. 8A is a schematic view of a charging cable unit in accordance with a fifth embodiment of the present invention; Fig. 8B is a schematic block diagram of a display device of the charging cable unit in accordance with the fifth embodiment; and Fig. 8C shows an example of the display device thereof; Fig. 9A is a schematic block diagram of a display device of a charging cable unit in accordance with a sixth embodiment; and Figs. 9B to 9D are examples of the display device thereof;

Fig. 1OA is a schematic block diagram of another display device of the charging cable unit in accordance with the sixth embodiment, and Figs. 1OB to 1OD are examples of the another display device;

Fig. 11 is a schematic block diagram of a display device of a charging cable unit in accordance with a seventh embodiment;

Fig. 12 is a schematic block diagram of a display device of a charging cable unit in accordance with an eighth embodiment ;

Figs. 13A to 13C are views for explaining a display device of the charging cable unit in accordance with the eighth embodiment; Fig. 13D is a front view of another display device thereof;

Fig. 14 is a schematic configuration diagram of a charging system in accordance with a ninth embodiment of the present invention;

Fig. 15A is a schematic block diagram of a transmission device used in the charging system of the ninth embodiment ;

Fig. 15B is a schematic block diagram of a display- device used in the charging system of the ninth embodiment; Figs. 16A to 16C are display examples of the display device shown in Fig. 15B;

Fig. 17 is a graph showing characteristics of charging to the secondary cell;

Fig. 18 is a schematic block diagram of a transmission device employed in a charging system in accordance with a tenth embodiment of the present invention;

Fig. 19 is a schematic configuration diagram of a charging system in accordance with an eleventh embodiment of the present invention; Fig. 2OA is a display example of a display device employed in the charging system of the eleventh embodiment; and Fig. 2OB is a schematic block diagram thereof;

Fig. 21A is a schematic block diagram of a transmission device employed in a charging system in accordance with a twelfth embodiment of the present invention; and Fig. 21B is a schematic block diagram of a display device used therein; and

Fig. 22A is a schematic view of a system using a charging cable unit of a conventional example; and Fig. 22B is a view showing another example of the conventional charging cable unit. Detailed Description of the Embodiments

Hereinafter, embodiments of the present invention will be described in more detail with reference to accompanying drawings which forms a part hereof. A charging cable unit of the present invention is used to supply a charging current to a battery mounted in an electric vehicle, and especially make it capable of charging of a plurality of electric vehicles.

(First Embodiment)

Fig. 1 is a schematic view of a system using a charging cable unit BB in accordance with a first embodiment. The charging cable unit BB of this embodiment includes an plug 102 adapted to detachably connected to a socket (plug receptacle) supplied with commercial power, a plurality of (e.g., two in this embodiment) cable connectors 104A each of which is adapted to be detachably connected to a connector (not shown) of an electric vehicle, and a switching unit (selection means) 103 for selecting one cable connector 104A through which charging current is supplied. Additionally, the cable connectors 104A and the plug 102 are connected to the switching unit 103 through a charging cable 101. The electric vehicle C of this embodiment includes a vehicle using a battery alone as its power source and a so-called hybrid vehicle using a combination of a battery and gasoline as its power source.

The switching unit 103 is a unit for switching a cable connector 104A at a feeding point, and, as shown in Fig. 2A, has a contact portion 103b including a plurality of (e.g., three in Fig. 2A) groups of switch contacts provided therein. Further, each switch contact of the contact portion 103b can be substantially simultaneously switched to either one of the cable connectors 104A by a switch 103a provided on the body surface of the switching unit. In addition, each of powers L and N and the ground are connected to the respective common terminals of the switch contacts to thereby supply a commercial power to a selected cable connector 104A. As shown in Fig. 3A, the cable connector 104A has an approximately circular cylindrical connector body and a plurality of (e.g., four in Fig. 3A) pin receptacles 141 protruded from the side of the connector body opposite to the charging cable 101. The pin receptacles are insertion fitted and connected by a plurality of connecting pins (not shown) provided on the connector of the electric vehicle C.

Further, an insertion fitting wall 143 for enclosing the pin receptacles 141 is protruded around the pin receptacles 141.

Next, the charging operation using the charging cable unit BB in accordance with this embodiment will be described. First, when the cable connectors 104A are respectively connected to the connectors of the electric vehicles C and the plug 102 is plugged in the socket AA, commercial power is supplied to the corresponding electric vehicle C through a cable connector 104A selected by the switch 103a, thereby performing charging of the battery mounted in the electric vehicle C. Thereafter, when a predetermined time is lapsed and the battery is fully charged, the switch 103a is manipulated to switch the contact portion 103b to another cable connector 104A and supply commercial power to the corresponding electric vehicle C. When the batteries of both electric vehicles C are fully charged after the lapse of a predetermined time, the plug 102 is removed from the socket AA and the respective cable connectors 104A are removed from the respective electric vehicles C, thereby completing the charging operation.

Meanwhile, the UL standard and the IEC standard enact that an electric leakage breaker is to be arranged less than 30cm from the socket. In the charging cable unit BB of the present invention, an electric leakage breaker 105 may be arranged at a location less than 30cm away from the plug 102 which is inserted and connected to the socket AA as shown in Fig. 4, and the provision of such an electric leakage breaker 105 can realize a charging cable unit BB with improved safety. The electric leakage breaker 105 incorporates a relay (not shown) for switching on/off the contacts based on a detection result of a leakage detection unit (not shown) , so that, upon detection of an electric leakage by the leakage detection unit, the contacts are switched off to cut off power feeding to the respective cable connectors 104A. With this embodiment, a cable connector 104A at a feeding point may be easily selected by the switching unit 103 among the cable connectors 104A respectively connected to the electric vehicles C and, therefore, the working efficiency for charging the electric vehicles can be improved comparing to the conventional example.

In this embodiment, although the charging cable unit BB uses the switching unit 103 for manually switching the contact portion 103b via the switch 103a, a switching unit 103 for automatically switching the contact portion 103b by, e.g., an electric signal from an electric vehicle C may be used. Fig. 6B shows an example of a circuit diagram of the switching unit 103 for automatically switching the contact portion 103b. This switching unit 103 includes a contact portion 103b having a plurality of (e.g., four in Fig. 2B) switch contacts and a controller 107 for receiving an electric signal (e.g., signal indicative of charging completion) inputted from an electric vehicle C and switching the contact portion 3b in response to the input electric signal. Additionally, the contact portion 3b may be switched by detecting a charging current to the battery instead of the electric signal. Next, the charging operation by employing the charging cable unit BB having the switching unit 103 shown in Fig. 2B will be described. First, when the cable connectors 104A are respectively connected to the connectors of the electric vehicles C and the plug 102 is plugged in the socket AA, a commercial power is supplied to the corresponding electric vehicle C through a cable connector 104A selected by the controller 107, thereby performing charging of the battery mounted in the selected electric vehicle C. Thereafter, when the charging of the battery is complete and the electric signal is inputted to the controller 107 from the electric vehicle C, the control unit 107 switches the contact portion 103b to the cable connector 104A at the other side, thereby starting power feeding to the electric vehicle C connected to the corresponding cable connector 104A.

With this configuration, since a cable connector 104A at a feeding point is sequentially and automatically switched by the switching unit 103, all of the electric vehicles C can be charged simply by connecting the charging cable 101 to the electric vehicles C via their respective cable connectors 104A. Also, although there is a need to set charging conditions, such as voltage and current, based on the number of electric vehicles to be connected when charging all of the electric vehicles C at a time, in this embodiment the electric vehicles are sequentially charged one by one and therefore there is no need to change the charging conditions, thus realizing an easy-to-use charging cable unit B.

In the charging cable unit B shown in Fig. 4, although the electric leakage breaker 105 is provided separately from the switching unit 103, the electric leakage breaker 105 may be included in, e.g., the switching unit 103.

(Second Embodiment) Fig. 5 is a schematic view of a system using a charging cable unit BB of a second embodiment. While the charging cable 101 of the first embodiment includes a single cable, a charging cable 101 of this embodiment includes a plurality of charging cables 101A and 101B(e.g., two in this embodiment) . Other configurations are the same as the charging cable unit BB shown in Fig. 4, and the same reference numerals are assigned to the same components a description of which will be omitted.

A plug 102 to be inserted and connected to a socket AA is provided at one end of the charging cable 101A, and a cable connector 104A is provided at the other end thereof. An electric leakage breaker 5 is provided between the plug 102 and the cable connector 104A (at a location less than 30cm from the plug 102) . Meanwhile, a cable connector 104B is provided at one end (the charging cable 101A side) of the charging cable 101B and connected to the cable connector 104A of the charging cable 101A, and a plurality of (e.g., two in this embodiment) cable connectors 104A are provided at the other end of the charging cable 101B.

Further, a switching unit 103 with a switch 103a provided on a body surface thereof is provided between the cable connectors 104A and the cable connector 104B on the charging cable 101B. The charging cable 101 of this embodiment includes the charging cables 101A and 101B connected in series via the cable connectors 104A and 104B and a contact portion 103b is switched to either one of the cable connectors 104A by manipulating the switch 103a of the switching unit 103.

As shown in Fig. 3A, the cable connector 104A has an approximately circular cylindrical connector body and a plurality of (e.g., four in Fig. 3A) connecting pins 142 are protruded on the side of the connector body opposite to the charging cable 101. Thus, the connecting pins 142 are respectively insertion fitted and connected to their corresponding pin receptacles 141 of the cable connector 104A such that the cable connector 104A and the cable connector 104B are connected to each other.

In addition, the operation of charging an electric vehicle C is the same as that in the first embodiment, so the description thereof will be omitted in this embodiment. Here, in the charging cable unit B of this embodiment, when charging one electric vehicle C, the charging cable IA alone is enough, while when charging a plurality of electric vehicles C, the charging cable IB is connected to the charging cable IA to enable charging. In this charging cable unit BB, the switching unit 103 is provided at the charging cable 101B (extension cable) and therefore the cable connector 104A can be branched into a plural number cables if required by connecting the charging cable 101B to the charging cable 101A. Also, even if the electric vehicle C is at a location away from the socket AA, the charging cable 101 can be extended by connecting the charging cables 101A and 101B in series, thus enabling a charging operation. In addition, although this embodiment has been described in a case where the number of cables connected in series is two, the number of the cables may be three or more. Also, although this embodiment uses the switching unit 103 which is manually switched by the switch 103a, the switching unit 103 may be automatically switched as shown in Fig. 2B.

(Third Embodiment) Fig. 6A is a schematic view of a system using a charging cable unit B in accordance with a third embodiment. This embodiment is different from the first and second embodiments in that the charging cable unit BB is provided with a winding drum (winding means) 106 for winding a charging cable 101. The same reference numerals are assigned to the same components as the first and second embodiments, and so a description thereof will be omitted.

The charging cable unit BB of this embodiment includes an plug 102, a plurality of (e.g., two in this embodiment) cable connectors 104A, a switching unit 103, and the winding drum 106 for winding the charging cable 101. In this embodiment, a contact portion 103b is switched to either one of the cable connectors 104A by manipulating a switch 103a of the switching unit 103.

In addition, the operation of charging an electric vehicle C is the same as that of the first embodiment, so the description thereof is omitted in this embodiment.

With this embodiment, the length of the charging cable 101 to be pulled out can be adjusted when in used, which enhances the convenience in use. The charging cable 101 can be wound on the winding drum 106 after using to thereby improve the ease of storage.

Although the charging cable 101 is formed of one cable in this embodiment, it may include, e.g., a charging cable 101B integrally formed with the winding drum 106 and a charging cable 101A to be connected to a connector 106a provided on a side surface of the winding drum 106 via the cable connector 104A, as shown in Fig. 6B. In the latter case, the length of the charging cable IB to be pulled out can be adjusted when in use to thereby improve the convenience in use, and the charging cable 101B can be wound on the winding drum 106 after using to thereby improve the ease of storage. Additionally, although this embodiment employs the switching unit 103 which is manually switched by the switch 103a, the switching unit 103 may be automatically switched as shown in Fig. 6B.

(Fourth Embodiment)

A fourth embodiment of a charging cable unit BB in accordance with the present invention will be described based on Fig. 7. In the first to third embodiments, when an electric leakage is detected, the respective contacts of the relay provided in the electric leakage breaker 105 are switched off to cut off power feeding to all of the cable connectors 104A. However, when the electric leakage is detected, respective switch contacts of a contact portion 103b provided in a switching unit 103 are switched to the contacts which are not connected to any of the cable connectors 104A, in this embodiment, thereby cutting off power feeding to all of cable connectors 104A. Also, other configurations are the same as the first to third embodiments, and the same reference numerals are assigned to the same components a description of which will be omitted.

As shown in Fig. 7, the switching unit 103 of this embodiment includes the contact portion 103b which has a plurality of (e.g., four in Fig. 7) switch contacts, and a leakage detection unit (leakage detection means) 108 for detecting a leakage current flowing through a charging cable 101. The switching unit 103 further includes a controller 107 for receiving a charging completion signal inputted from an electric vehicle C and/or a leakage detection signal inputted from the leakage detection unit 108, and switching the contact portion 103b in response to at least one of the received electric signals. Further, the leakage detection unit 108 is provided with a leakage detection circuit 1082 for detecting a leakage current flowing between each of power wires 101a (lines for supplying powers L and N) and the ground and a leakage control circuit 1081 for outputting a leakage detection signal to the controller 107 based on a detection result of the leakage detection circuit 1082.

Each of the switch contacts of the contact portion 103b is switchable to three positions as shown in Fig. 7, in which two of them are connected to the cable connectors 104A, respectively, and the remaining one is not connected. That is, the switching unit 103 of this embodiment can switch over between the state of power feeding to a cable connector 104A selected among the cable connectors 104A and the state of cutting off power feeding to all of the cable connectors 104A. When the electric leakage is detected by the leakage detection unit 108, power feeding to all of the cable connectors 104A is cut off (that is, the switch contacts are switched to unconnnected contacts) . When the cable connectors 104A are respectively connected to the connectors of electric vehicles C and an plug 102 is inserted to the socket AA, a commercial power is supplied to the corresponding electric vehicle C through a cable connector 104A selected by the controller 107, thereby performing charging of the battery mounted in the electric vehicle C. While charging the electric vehicle C, when the leakage detection circuit 1082 of the leakage detection unit 108 detects an electric leakage, the leakage control unit 1081 outputs a leakage detection signal to the controller 107. Thus, when the leakage detection signal is inputted to the controller 107, the controller 107 switches all of the switch contacts of the contact portion 103b to unconnected contacts to thereby cut off power feeding to both of the cable connectors 104A and 104A.

With this embodiment, since all of the switch contacts of the contact portion 103b are switched to unconnected contacts when the electric leakage is detected by the leakage detection unit 108, the leakage detection unit 108 need not be provided with a relay or the like for cutting off power feeding, which assists in reducing the number of parts.

In the above, while the first to fourth embodiments have been described with respect to a case where there are two cable connectors 104A, the number of cable connectors 104A is not limited to two, but may be three or more. Furthermore, while in the first to fourth embodiments a signal line for transmitting an electric signal outputted from an electric vehicle C is provided separately from power wires, the electric signal may be superimposed on the power lines so as to be transmitted to the switching unit 103 by power line carrier communications.

(Fifth Embodiment)

Hereinafter, a second embodiment of the present invention will be described with reference to Figs. 8A to 8C. Fig. 8A is a schematic view of a system using a charging cable unit Al. The charging cable unit Al of this embodiment includes a power plug 3, a cable connector G, and a display device 4. The power plug 3 is detachably connected to a power socket B (e.g., embedded socket, waterproof socket, or the like) which is supplied with, e.g., a commercial power source. The cable connector G is electrically connected to the power plug 3 via a power cable 6, and detachably connected to a connector (not shown) of an electric vehicle (an equipment to be powered) C which is supplied with a commercial power source to charge a secondary cell mounted therein.

The display device 4 is provided on the power cable 6. The cable connector G is conventionally well known and a detailed description thereof will be omitted. In this embodiment, the electric vehicle C includes a so-called hybrid car that runs on a combination of a secondary cell (battery) and gasoline as a power source, as well as a car that runs only on a secondary battery as a power source.

The display device 4 displays charging information or the like of the electric vehicle C and, as shown in Fig. 8B, includes a current measuring unit 43 (e.g., current transformer) for measuring current flowing through one of power lines Ll, a power calculating unit 41 (e.g., an integrating wattmeter) for integrating an amount of power supplied to the electric vehicle C based on a measurement result from the current measuring unit 43 and a power supply voltage supplied to the power calculating unit 41. The display device 4 further includes a display unit (display) 42 for displaying the integrated power calculated by the power calculating unit 41. A reference numeral L2 shown in Fig. 8B represents a ground line. The display unit 42 includes, e.g., a liquid crystal panel, and, as shown in Fig. 8C, is provided to expose on one surface of a rectangular device body, which numerically displays the integrated amount of power (the integrated power calculated by the power calculating unit 41) since the start of power feeding to the electric vehicle C.

When the cable connector G is connected to the connector of the electric vehicle C and the power plug 3 is plugged in the power socket B, the commercial power is supplied to the electric vehicle C to thus perform the charging of the secondary cell mounted in the electric vehicle C. Meanwhile, the power calculating unit 41 integrates the amount of power consumed in the charging based on the measurement result from the current measuring unit 43 and the power supply voltage supplied to the power calculating unit 41. In addition, the integrated power calculated by the power calculating unit 41 is displayed on the display unit 42 (see, e.g., Fig. 8C) .

With this embodiment, since the amount of power supplied to the electric vehicle C is displayed on the display unit 42, it can estimate the time when the charging will be completed based on the amount of power being displayed. Accordingly, by using the charging cable unit Al, it is not necessary for the user to visit the charging place many times to check the charging status, unlike in the conventional example, thereby making it easy for the user to find out the charging completion time because it can be estimated.

Additionally, although the display device 4 is disposed on the side of the power plug 3 in Fig. 8A, it may be disposed on the side of the cable connector G, and the arrangement position of the display device 4 is not specially limited. Also, the display unit 42 is not limited to a liquid crystal panel, but may include, e.g., a 7- segment display.

(Sixth Embodiment)

Hereinafter, a charging cable unit in accordance with a sixth embodiment of the present invention will be described with reference to Figs. 9A to 9D and Figs. 1OA to 10D.

In the fifth embodiment, the integrated power calculated by the power calculating unit 41 (i.e., cumulative amount of power consumed in the charging of the electric vehicle C) is displayed on the display unit 42, while this embodiment is different from the above in that electricity cost or elapsed charging time, which is calculated on the basis of the integrated power, is displayed along with the integrated power on the display unit 42. Other configurations are the same as those of the fifth embodiment, and the same reference numerals are assigned to the same components so that descriptions thereof will be omitted.

The display device 4A of the charging cable unit in accordance with the sixth embodiment includes, as shown in Fig. 9A, a power calculating unit 41, a display unit 42, a current measuring unit 43, and a control unit 44. The control unit 44 may be of, e.g., a CPU, and calculates electricity cost and integrates an elapsed charging time based on the integrated power calculated by the power calculating unit 41 (i.e., cumulative amount of power consumed in the charging of the electric vehicle C) . In addition, as for the elapsed charging time, times during which a detected value at the current measuring unit 43 exceeds a predetermined value are integrated. Further, the calculated electricity cost and the integrated elapsed charging time are numerically displayed on the display unit 42. Alternatively, the amount of power used in charging each electric vehicle may be individually displayed together on the display unit 42.

When the cable connector G is connected to the cable connector of the electric vehicle C and the power plug 3 is plugged in the power socket B, the commercial power is supplied to the electric vehicle C to thus perform the charging of the secondary cell installed in the electric vehicle C. Meanwhile, the power calculating unit 41 integrates the amount of power consumed in the charging based on the measurement result of the current measuring unit 43 and the power supply voltage supplied to the unit 41 itself .

In addition, the control unit 44 calculates electricity cost and an elapsed charging time on the basis of the integrated power calculated by the power calculating unit 41. Then, the display unit 42 may display electricity cost along with an amount of power used (integrated power calculated by the power calculating unit 41) as shown in Fig. 9B, or display electric charges and elapsed charging time along with the amount of power used as shown in Fig. 9C. Further, as shown in Fig. 9D, the amounts of powers used in charging, e.g., two electric vehicles may be individually displayed together.

Next, Fig. 1OA is a schematic block diagram of another display device 4B of this embodiment. The display device 4B also displays electric charges and/or elapsed charging time along with the amount of power used as in the display device 4A shown in Fig. 9A (see Figs. 9B to 9D) . Further, the display device 4B can change contents to be displayed on the display unit 42 by pressing a display switch 46.

This display device 4B includes, as shown in Fig. 1OA, a power calculating unit 41, a display unit 42, a current measuring unit 43, the control unit 44, a display control unit 45 for controlling the display unit 42, and the display switch 46 for changing over contents to be displayed on the display unit 42. For example, provided that the displayed contents are switched between an amount of power used and electric charges, the display control unit 45 alternately switches the display of the display unit 42 between the amount of power used and electric charges from the state shown in Fig. 1OB each time the display switch 46 is pressed (see Fig. 10C) .

Further, if the displayed contents are switched among the amount of power used, electric charges, and an elapsed charging time, the display control unit 45 sequentially switches the display of the display unit 42 among the amount of power used, electric charges, and the elapsed charging time from the state shown in Fig. 1OB each time the display switch 46 is pressed (see Fig. 10D) . The sequence of the display is not limited to this embodiment.

With this embodiment, since the elapsed charging time is displayed along with the amount of power used (i.e., the amount of power supplied to the electric vehicle C) , a charging cable unit which is easy to be used can be provided, like in the fifth embodiment. Moreover, in a case where electric charges is displayed, the user is able to know the electric charges required for one charging operation, thereby offering convenience to the user.

(Seventh Embodiment)

A charging cable unit in accordance with a seventh embodiment of the present invention will be described based on Fig. 11. This embodiment is different from the fifth and sixth embodiments in that charging information containing an estimated charging completion time is sent to the display device 4C from the electric vehicle C. The same components as the second and third embodiments are given the same reference numerals, and so a description thereof will be omitted.

The display device 4C of the charging cable unit in accordance with this embodiment includes, as shown in Fig. 11, a power calculating unit 41, a display unit 42, a current measuring unit 43, a control unit 44, a display control unit 45, and a display switch 46. The display- device 4C further includes a signal receiving unit 47 for extracting a charging information signal transmitted via power lines Ll from the electric vehicle C from a power supply voltage, and a blocking filter 48 for preventing signal leakage to a power system. In this embodiment, an estimated charging completion time is included in the charging information.

In this embodiment thus configured, when the cable connector G is connected to the connector of the electric vehicle C and the power plug 3 is plugged in the power socket B, the commercial power is supplied to the electric vehicle C to thereby perform the charging of the secondary cell mounted in the electric vehicle C. While charging the battery, the charging information signal is sent from the electric vehicle C via the power lines Ll.

Meanwhile, in the display device 4C, the charging information signal received through the signal receiving unit 47 is inputted to the control unit 44 and the control unit 44 outputs, along with the charging information, an integrated power of the power calculating unit 41, electric charges, and/or the like to the display control unit 45. Then, the display control unit 45 displays the estimated charging completion time contained in the charging information signal on the display unit 42, along with the integrated power, the electric charges, and/or the like. With this embodiment, since the estimated charging completion time is displayed on the display unit 42, the charging completion time can be checked accurately.

In addition, while this embodiment uses so-called power line carrier communications as a method of transmitting the charging information, for example, radio communications units may be arranged in the electric vehicle C and the display device 4, respectively, to transmit the charging information by radio communications .

(Eighth Embodiment)

A charging cable unit in accordance with a eighth embodiment of the present invention will be described based on Figs. 12 and 13A to 13D. The UL standard or the IEC standard describes that an electric leakage breaker should be arranged at a location less than 30cm from an outlet socket. Therefore, in this embodiment, an electric leakage breaker 5 is arranged at a location less than 30cm from a power plug 3 which is plugged in and connected to the power socket B, which is different from the fifth to seventh embodiments. Hereinafter, the same components are given the same reference numerals, and so a description thereof will be omitted. In this embodiment, the electric leakage breaker 5 is included in the display device 4D.

The electric leakage breaker 5 includes, as shown in Fig. 12a leakage detecting unit 53 for detecting a leakage current flowing between power lines Ll and a ground line L2 , a relay driving unit 52 for opening and closing relay contacts 56 and 56 provided on a current flowing path of the power lines Ll, a leakage control unit 51 for controlling the relay driving unit 52 to switch on/off the relay contacts 56 based on a detection result from the leakage detecting unit 53. The electric leakage breaker 5 further includes a leakage test switch 54 for virtually simulating an electric leakage state and a reset switch 55 for releasing a tripped state caused by an electric leakage. In this embodiment, a leakage detection means is implemented by the leakage detecting unit 53, a switching means is implemented by the relay contacts 56, and an electric leakage breaking is implemented by the leakage control unit 51 and the relay driving unit 52.

In this embodiment, when the cable connector G is connected to the connector of the electric vehicle C and the power plug 3 is plugged in the power socket B, a commercial power is supplied to the electric vehicle C to thus perform the charging of the secondary cell in the electric vehicle C. As shown in Fig. 13A, the amount of power used is displayed on the display device 4. Also, each time the display switch 46 is pressed, the display state is switched in the order of amount of power used -> electric charges -> elapsed charging time -> amount of power used (see Fig. 13B) . Further, when an electric leakage (a state where a leakage current is flowing between one of the power lines Ll and the ground line L2) is detected by the leakage detecting unit 53, the leakage control unit 51 controls the relay driving unit 52 to switch off the relay contacts 56 and stops power feeding to the electric vehicle C. At this point, a sign, e.g., 'electric leakage' in Fig. 13A which indicates the occurrence of the electric leakage is displayed on the display unit 42. In addition, when the leakage test switch 54 is pressed, the relay contacts 56 are switched off as described above. That is, a leakage state can be virtually simulated. At this time, a sign indicating that a leakage test is being simulated may be displayed. As shown in Fig. 13C, a luminescent display may be employed by a light emitting leakage test switch 54.

With this embodiment, if an electric leakage is detected by the leakage detecting unit 53, the relay contacts 56 are opened by the electric leakage breaker (the leakage control unit 51 and the relay driving unit 52) , such that power feeding to the electric vehicle C can be cut off. Therefore, a charging system with high safety standard can be provided. Moreover, since an occurrence of the electric leakage can be indicated on the display unit 42, an indicator for displaying the occurrence of the electric leakage may not be provided separately, thereby reducing cost increase.

Next, Fig. 13D is a front view of another display- device 4E. The display device 4E is different from the display device 4D and 4 shown in Figs. 12 and 13A in that a buzzer (notification means) 57 is provided. This display device 4E is adapted to output an alarm sound informing completion of the charging by the buzzer 57 when charging of the electric vehicle C is completed. Additionally, this display device 4E is configured to allow the user to confirm completion of charging by a charging completion signal contained in charging information sent from the electric vehicle C.

In this display device 4E, when the cable connector G is connected to the connector of the electric vehicle C and the power plug 3 is plugged in the power socket B, a commercial power is supplied to the electric vehicle C to thus perform the charging of the secondary cell in the electric vehicle C. When charging the secondary cell is completed after the lapse of a predetermined period of time, charging information containing a charging completion signal is sent from the electric vehicle C via the power lines Ll.

Then, when the signal receiving unit 47 of the display device 4E receives the charging information signal, the charging information signal is inputted to the control unit 44. The control unit 44 drives the buzzer 57 to output an alarm sound based on the charging completion signal contained in the charging information signal.

With this display device 4E, when the charging of the electric vehicle C is completed, an alarm sound informing completion of charging is outputted and, therefore, a user can know completion of charging even when he is at a location away from the charging place.

In addition, although in this embodiment the control unit 44 and the leakage control unit 51 are separately provided, they may be integrated. Moreover, while the display device 4 and 4A-4E, the buzzer 57, and the earth leakage breaker 5 set forth above may be separately provided and configured to be connectable via the power cable 6, a compact charging cable unit A may be realized wherein the display unit 42, the buzzer 57 and the earth leakage breaker 5 is accommodated together in a device body of the display device 4 as in this embodiment.

(Ninth Embodiment)

Fig. 14 is a schematic configuration diagram of a charging system in accordance with a ninth embodiment. The charging system includes a charging cable unit A2 for supplying, e.g., commercial power for charging an emergency battery D or an electric vehicle C (power receiving device) having a secondary cell installed therein, and a display device E provided in, e.g., a house for displaying charging information relating to the secondary cell. In this embodiment, the same reference numerals are assigned to the same as components of the fifth to eighth embodiments and a description thereof will be omitted. Here, the electric vehicle C includes a so-called hybrid car that runs on a combination of a secondary cell and gasoline as a power source, as well as a car that runs only on a secondary cell (battery) as a power source.

The charging cable unit A2 includes a power plug 3 detachably connected to a power socket B which is supplied with a commercial power, a cable connector G electrically connected to the power plug 3 via a power cable 6, and detachably connected to a connector (not shown) of an emergency battery D (or an electric vehicle C) which is supplied with the commercial power to charge a secondary cell installed therein. The charging cable unit A2 further includes a transmission device 9 for sending charging information relating to the secondary cell. In addition, the commercial power is supplied to the socket B and the display device E from a distribution board F provided in the house via a power wire 7.

The transmission device 9 includes, as shown in Fig. 15A, a current measuring circuit (e.g., current transformer) 94 for measuring current flowing through one of the power lines Ll, a power calculating unit 91 for calculating the amount of power supplied to the emergency battery D (or electric vehicle C) based on a measurement result of the current measuring circuit 94 and a power supply voltage supplied thereto. The transmission device 9 further includes a PLC circuit 93 for superimposing a charging information signal containing the integrated power calculated by the power calculating unit 91 on the power supply voltage, and a PLC control circuit 92 for controlling the PLC circuit 93.

In this embodiment, the power calculating unit 91 has a power circuit (not shown) and, therefore, operating power of the power calculating unit 91, the PLC control circuit 92, and the PLC circuit 93 is supplied through the power circuit. Further, the charging information signal contains an amount of power integrated by the power calculating unit 91 and a charging information acquisition unit is implemented by the power calculating unit 91. In this embodiment, a transmission unit is realized by the PLC circuit 93 and the PLC control circuit 92. The charging information is not limited to the integrated amount of power, but may be, for example, a current value measured by the current measuring circuit 94 or may be information (e.g., a charging voltage value of the secondary cell to be described later, an estimated charging completion time, and/or the like) that are acquired from the power receiving device .

Further, in this embodiment, the emergency battery D or electric vehicle C and the transmission device 9, e.g., PLC control circuit 92 are connected via a signal line (not shown), and a charging information signal containing, e.g., a charging voltage value and/or an estimated charging completion time of the secondary cell is transmitted to the transmission device 9 from the emergency battery D or electric vehicle C. Then, the transmission device 9 transmits, to the display device E, a charging information signal containing the acquired charging voltage value and/or the estimated charging completion time, and the integrated power. The display device E includes, as shown in Fig. 15B, a PLC signal receiving circuit 82 for separating the charging information signal sent from the charging cable unit A2 , from a power supply voltage, a display circuit 83 for displaying the received charging information, a display control circuit 84 for controlling contents to be displayed by the display unit 83. The display device E further includes a control circuit 81 for performing overall control of each of the parts in the display device E, a power circuit 85 for generating operating power required for each part, and a blocking filter 87 for preventing signal leakage to a power system. In this embodiment, receiving means is implemented by the PLC signal receiving circuit 82, and display means is implemented by the display control circuit 84 and the display unit 83. The control circuit 81 includes, e.g., CPU and calculates electric charges and elapsed charging time to be described later based on the integrated amount of power and the charging voltage value of the secondary cell that are contained in the charging information signal received by the PLC signal receiving circuit 82. And, the control circuit 81 outputs the calculated electric charges and elapsed charging time and the acquired estimated charging completion time to the display control circuit 84 along with the integrated amount of power.

The display unit 83 includes, e.g., a liquid crystal panel 83a as shown in Fig. 16A and displays one or more of the charging information (amount of power, electricity cost, elapsed charging time, or estimated charging completion time) on the liquid crystal panel 83a in response to an instruction from the display control circuit 84. In addition, the display unit is not limited to the liquid crystal panel, but may be, e.g., a 7 -segment display.

Fig. 17 is a graph showing the characteristics of charging to the secondary cell. The charge level of the secondary cell is generally obtained by measuring a cell voltage. In this embodiment, the control circuit 81 calculates, e.g., the elapsed charging time and/or remaining charging time by comparing a change in the charging voltage value of the secondary cell included in the charging information signal with the charging characteristics shown in Fig. 17.

The operation of this charging system will be described. First, when the cable connector G is connected to the connector of the emergency battery D or electric vehicle C and the power plug 3 is plugged in the power socket B, a commercial power is supplied to the emergency battery D or electric vehicle C to thus perform the charging of the secondary cell installed therein.

Then, the power calculating unit 91 of the transmission device 9 integrates the amount of power consumed in the charging based on the measurement result of the current measuring circuit 94 and the power supply voltage supplied thereto, and outputs to the PLC control circuit 93 as a charging information signal including the integrated amount of power and a charging voltage value of the secondary cell and/or an estimated charging completion time which are inputted from the emergency battery D or electric vehicle C. Then, the PLC control circuit 92 superimposes the charging information signal on the power supply voltage by using the PLC circuit 93.

Meanwhile, in the display device E, the charging information signal transmitted via power wires 7a and 7a is separated from the power supply voltage by the PLC signal receiving circuit 82, and inputted to the control circuit 81. The control circuit 81 calculates electric charges on the basis of the integrated amount of power contained in the charging information signal and further calculates the elapsed charging time and the remaining charging time on the basis of the change in the charging voltage value of the secondary cell to thus output them to the display control circuit 84. At this point, the estimated charging completion time is also outputted to the display control circuit 84.

The display control circuit 84 displays the cumulative amount of power used and electric charges on the liquid crystal panel 83a of the display unit 83, e.g., as shown in Fig. 16A. Although Fig. 16A shows that the cumulative amount of power used and the electric charges are displayed on the liquid crystal panel 83a, this is only an example and, e.g., elapsed charging time, remaining charging time, estimated time of completion of charging, and/or the like may be displayed thereon. Further, as shown in Fig. 16C, the amounts of powers used in charging, e.g., two electric vehicles may be individually displayed together.

With this embodiment, charging information relating to the secondary cell is displayed by the display device 9 which can be provided at home. Therefore, the user can know the charging condition without going to a charging place, and an easy-to-use charging system can be achieved. Additionally, a power receiving device (i.e., emergency battery D or electric vehicle C) is not needed to be equipped with a transmission function for transmitting the charging information, so that this system is applicable to various types of power receiving devices. As a result, a charging system with high flexibility can be achieved.

Furthermore, since the cumulative amount of power supplied to a power receiving device is displayed on the display device E, the user can estimate a charging completion time by comparing the known amount of power upon completion of charging with the displayed cumulative amount of power, without going to the charging place many times, so that convenience of the system can be further improved. If the display device E is configured to display electric charges thereon, the user is able to know how much electricity cost is required for charging, which improves its convenience.

Moreover, since the charging information signal is superimposed on the commercial power in this embodiment, a signal line for transmitting the charging information signal is not needed. As a result, a charging system can be realized relatively at a low cost. Further, if the display device E is configured to display the estimated charging completion time thereon, a time for completing charging can be known exactly.

For example, if a charging error is occurred, a signal indicative of a charging error is sent to the transmission device 9 from the emergency battery D or electric vehicle C via a signal line (not shown) , which is in turn sent to the display device E from the transmission device 9 by power line carrier communications. Thus, the occurrence of the charging error may be reported by an LED display circuit 86 as shown in Fig. 16B.

(Tenth Embodiment) A charging system in accordance with a tenth embodiment of the present invention will be described based on Fig. 13. This embodiment is different from the sixth embodiment in that the above-described charging cable unit A2 further includes an electric leakage breaking function. In addition, other configurations are the same as those of the sixth embodiment, and therefore, the same reference numerals are assigned to the same components so that its description will be omitted.

The charging system of this embodiment includes a charging cable unit A2 and a display device E. The charging cable unit A2 includes a power plug 3, a cable connector G, and a transmission device 9A. Further, the transmission device 9A includes, as shown in Fig. 18, a power calculating unit 91, a PLC control circuit 92, a PLC circuit 93, and an electric leakage breaker 5.

The electric leakage breaker 5 includes a leakage detecting unit (e.g., zero-phase current transformer) 53 for detecting a leakage current flowing between one of the power line Ll and the ground line L2 , a relay driving unit 52 for opening and closing relay contacts 56 arranged in the current flowing path of the power lines Ll, and a leakage control unit 51 for controlling the relay driving unit 52 to switch on/off the relay contacts 56 based on a detection result from the leakage detecting unit 53.

The electric leakage breaker 5 further includes a leakage test switch 54 for virtually simulating an electric leakage state, a reset switch 55 for releasing a tripped state caused by an electric leakage, and a buzzer 58 for alarming the occurrence of an electric leakage. In this embodiment, a leakage detection means is implemented by the leakage detecting unit 53, a switching means is implemented by the relay contacts 56, and a switching control means is realized by the leakage control unit 51 and the relay driving unit 52.

In this charging system, when the cable connector G is connected to the connector of the emergency battery D or electric vehicle C and the power plug 3 is plugged in the power socket B, a commercial power is supplied to the emergency battery D or electric vehicle C to thus perform the charging of the secondary cell in the emergency battery D or electric vehicle C. Meanwhile, if an electric leakage

(a state where a leakage current flows between one of the power lines Ll and the ground) is detected by the leakage detecting unit 53 while charging the battery, the leakage control unit 51 controls the relay driving unit 52 to switch off the relay contacts 56 and cut off power feeding to the emergency battery D or electric vehicle C. The leakage control unit 51 further operates the buzzer 58 to alarm the occurrence of the electric leakage. At this time, a signal indicative of the occurrence of the electric leakage may be sent to the display device E by power line carrier communications and, as shown in Fig. 12B, the occurrence of the electric leakage may be reported by the LED display circuit 86.

In addition, if the leakage test switch 54 is pressed, the relay contacts 56 are switched off as mentioned above, so that an electric leakage state can be virtually simulated. With this embodiment, when an electric leakage is detected by the leakage detecting unit 53, the relay contacts 56 are switched off by the relay driving unit 52, so that power feeding to the emergency battery D or electric vehicle C can be cut off to thereby provide a charging system with high safety standard.

Moreover, since the power calculating unit 91, PLC control circuit 92, PLC circuit 93, and the electric leakage breaker 5 are accommodated together in a device body of one transmission device 9A in this embodiment, a compact charging cable unit can be achieved.

(Eleventh Embodiment)

A charging system in accordance with an eighth embodiment of the present invention will be described referring to Fig. 19 and Figs 2OA to 2OB. This embodiment is different from the ninth and tenth embodiments in that a display device E is detachably connected to a power socket B with a plug 10. In addition, other configurations are the same as those of the ninth and tenth embodiments, and thus the same reference numerals are assigned to the same components and a description of which will be omitted.

The display device E of this embodiment includes, as shown in Figs. 2OA and 2OB, a PLC signal receiving circuit 82, a display unit 83, a display control circuit 84, a control circuit 81, a power circuit 85 and an LED display circuit 86. In the display device E, the plug 10 is provided at the end of a power cable 11 and is detachably connected to the power socket B. Thus, the display device E is plugged in and connected to the power socket B via the plug 10, thereby realizing a charging system including the charging cable unit A2 and the display device E (see Fig. 19) . The operation of this system is similar to those in the ninth and tenth embodiments, and so a description thereof will be omitted. With this embodiment, charging information relating to the secondary cell is displayed by the display device 9 which can be provided at home. Therefore, the user can know the charging condition without going to a charging place, and an easy-to-use charging system can be achieved. Additionally, a power receiving device (i.e., emergency battery D or electric vehicle C) is not needed to be equipped with a transmission function for transmitting the charging information, so that this system is applicable to various types of power receiving devices. As a result, a charging system with high flexibility can be achieved. Also, the socket to which this display device E is connected may be electrically connected to the socket B to which the charging cable unit A2 is connected and there can be achieved a charging system capable of knowing the charging condition of the secondary cell even at a location (home, etc.) away from a charging place.

(Twelfth Embodiment)

A charging system in accordance with a twelfth embodiment of the present invention will be described based on Figs. 21A and 21B. In the ninth to eleventh embodiments, charging information relating to the secondary cell is transmitted by so-called power line carrier communications, while, in this embodiment, the charging information is transmitted by radio waves. In addition, the same reference numerals are assigned to the same components as the ninth to eleventh embodiments, and so a description thereof will be omitted.

The transmission device 9B of this embodiment includes, as shown in Fig. 21A, the power calculating unit 91, a radio transmission circuit 95 for modulating a charging information signal containing an integrated power calculated by the power calculating unit 91 and radio- transmitting the modulated charging information signal through an antenna 97, and an insulated power circuit 96 for supplying operating power to the radio transmission circuit 95. In this embodiment, a transmission means is realized by the radio transmission circuit 95 and the antenna 97.

The display device El includes the control circuit 81, the display unit 83, the display control circuit 84, the power circuit 85, the LED display circuit 86, and an antenna 89 for receiving a radio signal. In addition, the display device El includes a radio receiving circuit 88 which receives the charging information signal by amplifying and demodulating the radio signal received by the antenna 89, and a cell 100 for supplying power to the power circuit 85.. The power may be supplied to the power circuit 85 by a commercial power source AC. In this embodiment, a receiving means is realized by the radio receiving circuit 88 and the antenna 89.

In this embodiment, when the cable connector G is connected to the connector of the emergency battery D or electric vehicle C and the power plug 3 is plugged in the power socket B, a commercial power is supplied to the emergency battery D or electric vehicle C to thus perform the charging of the secondary cell in the emergency battery D or electric vehicle C. The power calculating unit 91 of the transmission device 9B integrates the amount of power consumed for the charging based on the measurement result of the current measuring circuit 94 and the power supply- voltage supplied thereto. Then, the power calculating unit 91 outputs to the radio transmission circuit 95 a charging information signal containing the integrated power and the secondary cell charging voltage value which is inputted from the emergency battery D or electric vehicle C. The radio transmission circuit 95 modulates and radio- transmits the charging information signal through the antenna 97. Meanwhile, the radio receiving circuit 88 in the display device El amplifies and demodulates the radio signal received through the antenna 89 into the charging information signal, and then inputs the demodulated charging information signal to the control circuit 81. The control circuit 81 calculates electric charges and elapsed charging time on the basis of the input charging information, and inputs the calculated electric charges and elapsed charging time, and an integrated amount of power (amount of power consumed) to the display control circuit 84. Accordingly, the display control circuit 84 displays the amount of power consumed, an electric charges, an elapsed charging time, etc. on the liquid crystal panel 83a of the display unit 83.

With this embodiment, charging information relating to the secondary cell is displayed by the display device 9B which can be provided at home. Therefore, the user can know the charging condition without going to a charging place, and an easy-to-use charging system can be achieved. Additionally, a power receiving device (i.e., emergency- battery D or electric vehicle C) is not needed to be equipped with a transmission function for transmitting the charging information, so that this system is applicable to various types of power receiving devices. As a result, a charging system with high flexibility can be achieved.

Moreover, since this system uses radio waves, the charging condition of the secondary battery can be known even at a remote place as far as the radio waves can arrive.

While the invention has been shown and described with respect to the particular embodiments, it will be understood by those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

Claims

What is claimed is:

1. A charging cable unit comprising: a plug adapted to be detachably connected to a plug receptacle supplied with a commercial power; a plurality of cable connectors each of which is adapted to be detachably connected to a connector of an electric vehicle so that charging current is supplied to a battery of the electric vehicle connected via the connector; and a selection unit, to which the cable connectors and the plug are connected via a charging cable, for selecting among the cable connectors one cable connector through which the charging current is supplied.

2. The charging cable unit of claim 1, wherein the charging cable between the cable connectors and the plug includes a plurality of cables which are connected in series .

3. The charging cable unit of claim 1, wherein, when a charging of the electric vehicle connected to the selected cable connector, the selection unit automatically selects another one of the cable connectors through which the charging current is supplied.

4. The charging cable unit of claim 1, further comprising a leakage detection unit for detecting a leakage current flowing through the charging cable, wherein the selection unit is switchable between a power feeding state in which the charging current is supplied through the selected cable connector and the a power cutoff state in which no charging current is supplied through all of the cable connectors and, when an electric leakage is detected by the leakage detection unit, the selection unit cuts off power feeding to all of the cable connectors.

5. The charging cable unit of claim 1 or 2 , further comprising a winding unit for winding the charging cable.

6. The charging cable unit of any one of claims 1 to 4 , further comprising: a power calculating unit for integrating an amount of power supplied to a power receiving device of the electric vehicle, and a display device for displaying an integrated amount of power supplied to the power receiving device.

7. The charging cable unit of claim 6, wherein the display unit displays equivalent electric charges converted from the integrated amount of power calculated by the power calculating unit, an elapsed charging time, and/or the integrated amount of power supplied to the power receiving device of at least one electric vehicle.

8. The charging cable unit of any one of claims 1 to 4 , further comprising: a transmission apparatus including a charging information acquisition unit for obtaining charging information relating to a secondary cell of a power receiving device of the electric vehicle and a transmission unit for transmitting the acquired charging information; and a display device including a signal receiving unit for receiving a signal of the charging information transmitted from the transmission apparatus and a display unit for displaying the received charging information, wherein the display device is provided separately from the charging cable.

9. The charging cable unit of claim 8, wherein the transmission unit superimposes a signal of the charging information on commercial power, and the signal receiving unit separates the signal of the charging information superimposed on the commercial power therefrom.

10. The charging cable unit of claim 9, wherein the display device displays, on the display unit, an amount of power supplied to the power receiving device of at least one electric vehicle, and/or electric charges calculated from the amount of power.