WO2017140623A1

WO2017140623A1 - Single electrode-pair battery

Info

Publication number: WO2017140623A1
Application number: PCT/EP2017/053160
Authority: WO
Inventors: Robert Koch; Mark KOTIK; Paul Frick
Original assignee: Robert Bosch Gmbh
Priority date: 2016-02-17
Filing date: 2017-02-13
Publication date: 2017-08-24

Abstract

An electrochemical cell includes a single positive electrode, a single negative electrode, and a separator that is disposed between the positive electrode and the negative electrode. The positive electrode, the negative electrode and the separator are arranged in a stacked configuration.

Description

SINGLE ELECTRODE-PAIR BATTERY FIELD

[001] The disclosure relates generally to electrochemical cells and, more particularly, to an electrochemical cell having a single electrode pair arranged in a stacked configuration.

BACKGROUND

[002] Battery packs provide power for various technologies ranging from portable electronics to renewable power systems and environmentally friendly vehicles. For example, hybrid electric vehicles (HEV) use a battery pack and an electric motor in conjunction with a combustion engine to increase fuel efficiency. Battery packs are formed of a plurality of battery modules, where each battery module includes several electrochemical cells. Within the battery modules, the cells are arranged in two or three dimensional arrays and are electrically connected in series or in parallel. Likewise, the battery modules within a battery pack are electrically connected in series or in parallel.

[003] Different cell types have emerged in order to deal with the space requirements of a very wide variety of installation situations, and the most common types used in automobiles are cylindrical cells, prismatic cells, and pouch cells. Regardless of cell type, each cell may include a cell housing and an electrode assembly disposed in the cell housing. The electrode assembly of some conventional lithium-ion batteries includes at least two metal-substrate electrodes separated by a porous membrane separator, immersed in an electrolyte. The electrodes are either stacked in a planar configuration or wound into a tight spiral that is frequently referred to as a jelly roll. The spiral configuration of the electrodes is easier to manufacture though is not very volumetrically efficient, while the stacked planar configuration of electrodes, while being more efficient in use of available space, is much more difficult to manufacture as it depends on individual plates being precisely placed in a stack or material being z-folded in a precise fashion.

[004] Larger area formats for the electrodes are typically not used for traditional cells as a charge resistance gradient forms based on the distance of the active material from the cell terminals. This gradient causes excess wear to occur during normal operation. SUMMARY

[005] In some aspects, a single-layer electrochemical cell includes a single positive electrode, a single negative electrode, and a separator that is disposed between the positive electrode and the negative electrode. The positive electrode, the negative electrode and the separator are arranged in a stacked configuration.

[006] In some aspects, a battery module includes a plurality of electrically connected cells, where each cell includes a single positive electrode, a single negative electrode, and a separator that is disposed between the positive electrode and the negative electrode, wherein the positive electrode, the negative electrode and the separator are arranged in a stacked configuration.

[007] In some embodiments, each cell of the module is electrically connected to an adjacent cell of the module, and the electrical connection is achieved by direct contact between one of the positive electrode and the negative electrode of one cell with the other of the positive electrode and the negative electrode of the adjacent cell.

[008] In some embodiments, the separator has the same peripheral shape and dimensions as the positive electrode and the negative electrode. In addition, a first adhesive is disposed between a peripheral edge of the separator and a peripheral edge of the positive electrode, and a second adhesive is disposed between a peripheral edge of the separator and a peripheral edge of the negative electrode.

[009] In some embodiments, the separator has a lesser dimension than the dimensions of the positive electrode and the negative electrode so that a peripheral edge of the separator resides within peripheral edges of the positive electrode and the negative electrode when the cell is viewed in top plan view. An adhesive is disposed between a peripheral edge of the positive electrode and a peripheral edge of the negative electrode such that the positive electrode is sealed to the negative electrode, and the adhesive surrounds a periphery of the separator.

[0010] In some embodiments, the separator has a greater dimension than the dimensions of the positive electrode and the negative electrode so that a peripheral edge of the separator surrounds peripheral edges of the positive and negative electrodes when the cell is viewed in top plan view. [0011] In some embodiments, a sealing adhesive is disposed between the positive electrode and the negative electrode, and the separator extends through the sealing material.

[0012] In some embodiments, the sealing material cooperates with the separator to provide a hermetic seal about a periphery of the cell.

[0013] In some embodiments, the electrochemical cell further includes a flexible laminate housing, and the positive electrode, the negative electrode and the separator are disposed in the housing. In addition, the housing is formed having openings that overlie each of the positive electrode and the negative electrode in such a way that outward facing surfaces of the positive electrode and the negative electrode are exposed.

[0014] In some embodiments, the flexible laminate housing comprises a first sheet of laminate material that is sealed to an outer surface of the positive electrode about a periphery of the periphery of the positive electrode, and a second sheet of laminate material that is sealed to an outer surface of the negative electrode about a periphery of the negative electrode. The first sheet of laminate material is sealed to the second sheet of laminate material about a periphery of the electrochemical cell.

[0015] In some embodiments, a seal is provided between each of the openings and the corresponding one of the positive electrode and the negative electrode.

[0016] In some aspects, an electrochemical cell consists of a single positive electrode, a single negative electrode, a separator that is disposed between the positive electrode and the negative electrode, an electrically isolating sealing element that joins a periphery of the positive electrode to a periphery of the negative electrode whereby the positive electrode and the negative electrode serve as a cell housing, and an electrolyte disposed within cell housing. In some embodiments, the positive electrode, the negative electrode and the separator are plates that are arranged in a stacked configuration.

[0017] In some aspects, a single electrode pair electrochemical cell includes metal substrates sealed around the edges with a sealant such as an adhesive and/or a laminated metal foil sheet to form a thin foil can. The outward facing sides of the electrode substrates form the terminals of the cell.

[0018] This arrangement provides essentially a large format fiat cell in which the upper and lower surfaces are electrically isolated and act as positive and negative terminals. This allows the cells to be stacked serially, eliminating the need for bus bars or complex terminal attachment. Additionally, the direct contact occurs immediately adjacent to the active material reaction sites, greatly reducing cell resistance relative to that of a traditional cell which requires current to travel a large distance through an electrode substrate.

[0019] Advantageously, the large surface area of the cell allows for a large capacity in a single electrode pair. As the cell charges and ages, the dimensions of some conventional cells expand in proportion to the number of electrode pairs. In contrast to these conventional cells, the single electrode pair cell disclosed herein contains one positive electrode and one negative electrode, and thus the expansion will be significantly less than in these conventional pouch cells. As multiple cells are stacked to increase voltage, the cell swelling over the entire stack will still be much less than in a stack of traditional pouch cells, as the number of electrode pairs in the entire stack is far fewer than the number over the traditional cell stack. This allows the cell stack enclosure to be less rigidly designed, as the cells will not exert as much displacement on the enclosure during operation than in a traditional design.

[0020] Since the electrochemical cell includes the single pair of electrodes,

manufacturing complexity and part count are both reduced. In addition, since the electrode substrates act as the enclosure, there is no discrete cell enclosure further reducing manufacturing costs and complexity. Moreover, some similar capacity cells of a conventional format may either require a larger wound diameter which in turn leads to a greater volume of unusable space in cell packing, or else an increase in the number of plates which need to be uniformly stacked in a prismatic or pouch format.

[0021] The single electrode pair electrochemical cell permits high speed stacking of many electrodes.

[0022] The single electrode pair electrochemical cell has very few components, and as few as five components in some embodiments. This is advantageous relative to some high part count in the stacked electrode concepts used in some conventional cells that increase the manufacturing quality risk. [0023] The single electrode pair electrochemical cell permits use of pressure contact between cells to form electrical connections therebetween, which advantageously allows for high power transfer.

[0024] Additional advantages of the single electrode pair electrochemical cell include a 93.9 percent volumetric efficiency for a 75 Ah cell, and up to 90 percent volumetric efficiency for a battery pack formed of the single electrode pair electrochemical cells. In some embodiments, 30kWh, 60kWh, 90kWh packs are scalable with same 1.0m x 1.7m footprint, and cell interconnections have almost zero contact resistance.

[0025] The details of one or more features, aspects, implementations, and advantages of this disclosure are set forth in the accompanying drawings, the detailed description, and the claims below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Fig. 1 is an exploded perspective view of a single layer cell.

[0027] Fig. 2 is a side sectional view of the single layer cell of Fig. 1 as seen along line 2— 2 with arrows showing the location of heat application.

[0028] Fig. 3 is a side sectional view of the single layer cell of Fig. 1 as seen along line 2— 2 following heat application along the broken line.

[0029] Fig. 4 is a side sectional view of the single layer cell of Fig. 1 as seen along line 2— 2 following formation and removal of the pockets.

[0030] Fig. 5 is an exploded perspective view of an alternative embodiment single layer cell.

[0031] Fig. 6 is a side sectional view of the single layer cell of Fig. 5 as seen along line 6— 6 following formation and removal of the pockets.

[0032] Fig. 7 is an exploded perspective view of another alternative embodiment single layer cell.

[0033] Fig. 8 is a side sectional view of the single layer cell of Fig. 7 as seen along line

8— 8 following formation and removal of the pockets.

[0034] Fig. 9 is a side sectional view of the single layer cell of Fig. 7 as seen along line

9— 9 following formation and removal of the pockets. [0035] Fig. 10 is an exploded perspective view of another alternative embodiment single layer cell.

[0036] Fig. 11 is a side sectional view of the single layer cell of Fig. 10 as seen along line

11— 1 1 following formation and removal of the pockets.

[0037] Fig. 12 is a side sectional view of the single layer cell of Fig. 10 as seen along line

12— 12 following formation and removal of the pockets.

[0038] Fig. 13 is an exploded perspective view of another alternative embodiment single layer cell.

[0039] Fig. 14 is a side sectional view of the single layer cell of Fig. 13 as seen along line 14—14.

[0040] Fig. 15 is an exploded perspective view of another alternative embodiment single layer cell.

[0041] Fig. 16 is a side sectional view of the single layer cell of Fig. 15 as seen along line 16—16.

[0042] Fig. 17 is a perspective view of another alternative embodiment single layer cell.

[0043] Fig. 18 is an exploded perspective view of the single layer cell of Fig. 17.

[0044] Fig. 19 is an exploded perspective view of another alternative embodiment single layer cell.

[0045] Fig. 20 is a perspective sectional view of the single layer cell of Fig. 19 as seen along line 20— 20.

[0046] Fig. 21 is a top plan view of the single layer cell of Fig. 19.

[0047] Fig. 22 is a top plan view of a single layer cell similar to Fig. 19 having a misaligned separator.

[0048] Fig. 23 is an exploded perspective view of another alternative embodiment single layer cell.

[0049] Fig. 24 is a side sectional view of the single layer cell of Fig. 23 as seen along line 24—24.

[0050] Fig. 25 is an exploded perspective view of another alternative embodiment single layer cell.

[0051] Fig. 26 is an exploded perspective view of another alternative embodiment single layer cell. [0052] Fig. 27 is a cross sectional view of a module including four cells.

[0053] Fig. 28 is a perspective view of an alternative embodiment module.

[0054] Fig. 29 is a perspective view of another alternative embodiment module.

[0055] Fig. 30 is an exploded perspective view of the single layer cell including bolt- receiving through holes in each electrode and separator.

[0056] Fig. 31 is cross-sectional view of a portion of a module illustrating a bolt passing through each cell to stabilize the stack of cells within the module.

[0057] Fig. 32 is an illustration of one possible method of manufacturing a single layer cell.

DETAILED DESCRIPTION

[0058] Referring to Figs. 1 -4, the single layer cell 10 as described herein consists of a single positive electrode 12, a single separator 14 and a single negative electrode 16 that are arranged in a single positive electrode-separator-negative electrode stack 18. The positive electrode 12 and negative electrode 16 are thin metal foil substrates that are provided on one side with a coating of an appropriate active material. The positive electrode 12 and negative electrode 16 are sealed around the edges with a sealant such as an adhesive 30 and/or a laminated metal foil sheet to form a thin foil electrochemical cell in which the outward facing sides of the substrates form the terminals of the cell, as discussed further below.

[0059] As used herein, the term "thin metal foil substrate" refers to an electrode substrate geometry that includes a length and width that are large (e.g., on the order of 1000 times larger) relative to the thickness. For example, in some applications, the electrodes 12, 16 may have a thickness of 0.04 mm to 0.10 mm, and a length and width of 20 mm to 20 m or more.

[0060] The positive electrode 12 and the negative electrode 16 may each have a layered structure to facilitate insertion and/or movement of lithium-ions. For example, in the illustrated embodiment, the positive electrode 12 is a thin metal foil substrate formed of a first electrically-conductive material such as copper. In addition, the positive electrode 12 includes a first active material 13 such as graphite that is provided on an inward- facing (e.g., negative electrode 16-facing) surface 12.1 thereof via for example a printing process. The first active material 13 is applied such that a space exists between the peripheral edge 12.2 of the positive electrode 12 and the first active material 13, whereby a clear lane 12.4 of bare substrate is provided about the peripheral edge 12.2 of the positive electrode 12.

[0061] The negative electrode 16 is a thin metal foil substrate formed of a second electrically-conductive material such as aluminum. In addition, the negative electrode 16 includes a second active material 17 such as a lithiated metal oxide coating that is provided on an inward-facing (e.g., positive electrode 12-facing) surface 16.1 thereof via for example a printing process. The second active material 17 is applied such that a space exists between the peripheral edge 16.2 of the negative electrode 16 and the second active material 17, whereby a clear lane 16.4 of bare substrate is provided about the peripheral edge 16.2 of the negative electrode 16.

[0062] The separator 14 is the same size and shape as the positive electrode 12 and the negative electrode 16, and is disposed between the positive electrode 12 and the negative electrode 16 within the electrode stack 18. The separator 14 is an electrically insulating and permeable membrane that functions to keep positive electrode 12 and the negative electrode 16 apart to prevent electrical short circuits while also allowing passage of ionic charge carriers provided in the electrolyte and that are needed to close the circuit during the passage of current within the cell 10. For example, the separator 14 may be a trilayer po lypropylene-po ly ethylene -po lypropylene membrane .

[0063] In addition to the electrode stack 18, the single layer cell 10 includes a pair of sheets 20 of plastic laminated metal foil such as is used to form the housings of some pouch-type battery cells. The sheets 20 are in the shape of a wide walled '0' when viewed in top plan view. A first sheet 20.1 of the pair of sheets 20 is placed on one side of the stack 18 so as to confront the positive electrode 12, and the second sheet 20.2 of the pair of sheets 20 is placed on the opposed side of the stack 18 so as to confront the negative electrode 16. The sheets 20 are arranged that such that the positive electrode 12 and negative electrode 16 outward-facing surfaces are accessible through the openings 22 of the '0' shaped sheets 20. The openings 22 are sized to form an opening area that resides just within the peripheral edges 12.2, 16.2 of the positive electrode 12 and negative electrode 16. The first sheet 20.1 is sealed to the outward- facing surface 12.3 of the positive electrode 12 around the opening 22. Likewise, the second sheet 20.2 is sealed to the outward facing surface 16.3 of the negative electrode 16 around the opening 22.

[0064] The seal between the sheets 20 and the positive electrode 12 and the negative electrode 16 is hermetic and is achieved using an adhesive 30 that is compatible with the liquid electrolyte used within the cell 10. In some embodiments, the adhesive 30 may be a two-part epoxy adhesive. In other embodiments, the adhesive 30 may be a

thermoplastic adhesive such as hot melt adhesive (HMA). The HMA may be pre-formed into a substantially rigid frame configuration that is heated to form a seal at the time of cell assembly. In still other embodiments, the adhesive 30 may be a pressure sensitive adhesive.

[0065] The sheets 20 may be oversized relative to the size of the electrode stack 18 so that excess sheet material is provided along each of opposed edges 18.1 , 18.2 ofthe electrode stack 18. The excess material is used to form a pocket 23, 24 at each of the opposed edges 18.1, 18.2. For example, heat sealing is used to join the first and second sheets 20.1 , 20.2 adjacent to the first edge 18.1 to form a first pocket 23 that serves as a gas collection bag. In addition, a second pocket 24 is similarly formed by joining the first and second sheets 20.1 , 20.2 adjacent to the second edge 18.2 (see arrows 26, Fig. 2). The second pocket 24 serves as an electrolyte injection port. Both pockets 23, 24 are formed in such a way that they can be sealed from the cell 10 (see arrows 27, Fig. 2) for example by heat sealing following cell formation. After formation is complete, the pockets 23, 24 may be removed by cutting them from the first and second sheets 20.1 , 20.2, for example along a cut line represented by broken lines in Fig. 3.

[0066] When the pockets 23, 24 have been removed from the cell 10 (Fig. 4), the resulting cell 10 is formed of a single positive electrode -negative electrode pair in which the outward facing sides of the positive electrode 12 and negative electrode 16 are exposed via the openings 22 and form the terminals of the cell 10.

[0067] In some embodiments, during cell manufacture, electrolyte fill and de-gas may be achieved in a process similar to a carbon fiber lay-up process, including laying dry sheets of fiber, enclosing in a flexible bag, adding resin/electrolyte on one side of the cell, and pulling via vacuum on the opposed side of the cell. [0068] The positive electrode 12 and the negative electrode 16 act as an impermeable layer, enclosure and terminals of the cell 10. In some embodiments, the positive electrode 12 and the negative electrode 16 may have a large surface area, whereby the cell 10 is capable of providing high power.

[0069] Referring to Figs. 5 and 6, an alternative embodiment single layer cell 100 is similar to the cell 10 illustrated in Figs. 1-4, and common reference numbers are used to refer to common elements. The cell 100 illustrated in Figs. 5 and 6 differs from the earlier embodiment in that it includes two electrically conductive plates 102, 104. A first one of the plates 102 is disposed between the positive electrode 12 and the first sheet 20.1 , and a second one of the plates 104 is disposed between the negative electrode 16 and the second sheet 20.2. Beads of adhesive 30 are applied around the opening 22 between the first sheet 20.1 and the first plate 102, and between the first plate 102 and the positive electrode 12. Additional beads of adhesive 30 are applied between the negative electrode 16 and the second plate 104, and around the opening 22 between the second plate 104 and the second sheet 20.2.

[0070] The plates 102, 104 may be formed of metal and have a greater thickness than the positive electrode 12 and negative electrode 16. For example, the plates 102, 104 may be twice as thick as the positive electrode 12 and the negative electrode 16. The plates 102, 104 are placed on the outermost sides of the stack 18. The peripheral edges of the plates 102, 104 are covered with the "O" shaped plastic laminated metal foil material 20 as in the embodiment shown in Figs 1 -4, and excess sheet material is removed following cell formation as discussed above with respect to Figs. 1-4.

[0071] The plates 102, 104 may act as a strain and bend relief to facilitate handling of the stack 18 during manufacturing and assembly. In addition, the plates 102, 104 may be used to provide different electrical properties than those of the positive electrode 12 and negative electrode 16 and/or to avoid galvanic corrosion at the connection between the cell 100 and an external structure.

[0072] For example, in some embodiments, it may be useful to provide alternatives to using a nickel clad substrate. In these cases, an electrically conductive thin foil pouch may be added to the cell. In addition, or alternatively, the outer layer may be composed of aluminum or be nickel-clad, which would provide corrosion resistance and improve the structure of the cell to aid in handling of the cell.

[0073] Referring to Figs. 7-9, another alternative embodiment single layer cell 200 is similar to the cell 10 illustrated in Figs. 1-4, and common reference numbers are used to refer to common elements. The cell 200 illustrated in Figs. 7 -9 differs from the cell 10 illustrated in Figs. 1-4 in that the positive electrode 12 and the negative electrode 16 are sealed to each other using a first bead 30.1 of the adhesive 30 along a pair of opposed stack edges 18.3, 18.4 rather than around the entire periphery of the stack 18 as shown in Figs 1 -4. The first bead 30(a) of the adhesive 30 prevents electrical contact between the positive electrode 12 and negative electrode 16 along the opposed edges and seals the positive electrode 12 and negative electrode 16 on two sides of the rectangular stack 18.

[0074] The cell 200 illustrated in Figs. 7-9 further differs from the cell 10 illustrated in Figs 1 -4 in the configuration of the sheets 20' of plastic laminated metal foil. In the cell 200 illustrated in Figs. 7-9, four sheets 20' are provided, and each of the sheets 20' is free of openings and overlies an edge of the electrode stack 18. In particular, a first sheet 20'.1 overlies the positive electrode 12 along the first stack edge 18.1, a second sheet 20'.2 overlies the positive electrode 12 along the second, opposed stack edge 18.2, a third sheet 20'.3 underlies the negative electrode 16 along the first stack edge 18.1 in alignment with the first sheet 20'.1 , and a fourth sheet 20'.4 underlies the negative electrode along the second stack edge 18.2 in alignment with the second sheet 20'.2. The sheets 20' are placed on the stack 18 of the cell 200 along the non-sealed stack edges 18.1 , 18.2 to allow for creation of the pockets 23, 24 corresponding to a gas bag and electrolyte injection port along the opposed edges 18.1 , 18.2 as discussed with respect to Figs. 1-4. The sheets 20' are sealed to the corresponding edges 18.1 , 18.2 of the positive electrode 12 and negative electrode 16 using a second bead 30.2 of the adhesive 30.

[0075] The stack edges 18.1, 18.2 are sealed via joining of the sheets 20'along these edges subsequent to cell formation.

[0076] Referring to Figs. 10-12, an alternative embodiment single layer cell 300 is similar to the cell 200 illustrated in Figs. 7-9, and common reference numbers are used to refer to common elements. The cell 300 illustrated in Figs. 10-12 differs from the cell 200 illustrated in Figs. 7-9 in that it includes the two electrically conductive plates 102, 104 described above with respect to Figs. 5 and 6. A first one of the plates 102 is disposed between the positive electrode 12 and the first and second sheets 20'.1 , 20'.2. In addition, a second one of the plates 104 is disposed between the negative electrode 16 and the third and fourth sheets 20 '.3, 20 '.4.

[0077] To ensure that the cell 300 is free of leaks, adhesive 30 is strategically placed within the cell 300 as follows: Lines of adhesive 30.2 are applied along the first edge 18.1 between the first sheet 20'.1 and the first plate 102, andbetween the second plate 104 and the negative electrode 16. In addition, lines of adhesive 30.2 are applied along the second edge 18.2 between the second sheet 20'.2 and the first plate 102, and between the second plate 104 and the fourth sheet 20'.4. Frame shaped portions of the adhesive 30 are disposed between the peripheries of the first plate 102 and the positive electrode 12, and between the peripheries of the negative electrode 16 and the secondplate 104. In addition, lines of adhesive 30.1 are applied along the third and fourth edges 18.3, 18.4 between positive electrode 12 and the separator 14, and between the separator 14 and the negative electrode 16. The stack edges 18.1 , 18.2 are sealed via joining ofthe sheets 20'along these edges subsequent to cell formation.

[0078] As in the earlier embodiment, the plates 102, 104 may act as a strain and bend relief to facilitate handling of the stack 18 during manufacturing and assembly. In addition, the plates 102, 104 may be used to provide different electrical properties than those of the positive electrode 12 and negative electrode 16 and/or to avoid galvanic corrosion at the connection between the cell 300 and an external structure.

[0079] Referring to Figs. 13 and 14, another alternative embodiment single layer cell 400 is similar to the cell 10 illustrated in Figs. 1 -4, and common reference numbers are used to refer to common elements. The cell 400 illustrated in Figs. 13 and 14 differs from the cell 10 illustrated in Figs. 1-4 in that it omits the plastic laminated metal foil sheets 20. In addition, the separator 14 is made slightly smaller in size than the positive electrode 12 and negative electrode 16 so that a periphery of the separator 14 does not extend between the clear lanes 12.4, 16.4 ofthe positive electrode 12 and negative electrode 16. In the cell 400 illustrated in Figs. 13 and 14, a bead of adhesive 30, disposed outside a periphery of the separator 14 and along the clear lanes 12.4, 16.4, hermetically seals the positive electrode 12 to the negative electrode 16 and prevents an electrical short between the positive electrode 12 and the negative electrode 16. The adhesive 30 is applied in a frame-shaped configuration such that the positive electrode 12 and negative electrode 16 are sealed on all four sides.

[0080] The single layer cell 400 includes only five components. In particular, the single layer cell 400 includes the positive electrode 12, which is a foil substrate having the first active material pasted on an inward facing side, the negative electrode 16 which is a foil substrate having the second active material pasted on an inward facing side, the separator sheet 14 disposed between the positive electrode 12 and the negative electrode 16, the adhesive 30, and an electrolyte (not shown) that is sealed between the substrates 12, 16 by the adhesive 30. As in the previous embodiments, the positive electrode 12 and the negative electrode 16 act as an impermeable layer, enclosure and terminals.

[0081] As a non-limiting example of cell thickness, in some embodiments, the cell 400 may have a thickness, corresponding to a distance between the outer surfaces of the positive electrode 12 and negative electrode 16, in a range of 0.5 mm to 1.5 mm. In other embodiments, the cell 400 may have a thickness in a range of 0.2 mm to 0.5 mm. In still other embodiments, the cell 400 may have a thickness in a range of 0.15 to 0.35 mm.

[0082] In some embodiments, the single layer cell 400 has a large format (e.g., each positive and negative electrode plate has a large area) that provides direct contact terminals since the positive electrode 12 and the negative electrode 16 serve as terminals. By providing a large surface area, the cell 400 may be capable of providing high power. Moreover, the five-element single layer cell 400 is simple and easy to manufacture.

[0083] During manufacture of cell 400, at least one port (not shown) is provided through the seal 30 to permit electrolyte fill and gas evacuation. Following cell formation, the ports are sealed to retain electrolyte within the cell 400.

[0084] Referring to Figs. 15 and 16, another alternative embodiment single layer cell 800 is similar to the cell 400 illustrated in Figs. 13 and 14, and common reference numbers are used to refer to common elements. The cell 800 illustrated in Fig. 15 and 16 differs from the cell 400 illustrated in Figs. 13 and 14 in that the separator 14 is made the same size as the positive electrode 12 and negative electrode 16 so that a peripheral edge 14.2 of the separator 14 is aligned with the peripheral edges 12.2, 16.2 of the positive electrode 12 and negative electrode 16. A frame-shaped bead of adhesive 30 is disposed along the positive electrode clear lane 12.4 between an inner surface of the positive electrode 12 and the separator 14 and hermetically seals the positive electrode 12 to the separator 14. Another frame-shaped bead of adhesive 30 is disposed along the negative electrode clear lane 16.4 between an inner surface of the negative electrode 16 and the separator 14 and hermetically seals the negative electrode 16 to the separator 14. In this configuration, the adhesive 30 retains the separator 14 in place between the positive electrode 12 and negative electrode 16, and the separator 14 prevents an electrical short circuit between the positive electrode 12 and the negative electrode 16.

[0085] The single layer cell 800 includes only six components. In particular, the single layer cell 400 includes the positive electrode 12 having the first active material pasted on an inward facing side, a negative electrode 16 having the second active material pasted on an inward facing side, the separator sheet 14 disposed between the positive electrode and the negative electrode, two beads of sealant 30, and an electrolyte that is sealed between the substrates 12, 16 by the sealant 30. As in the previous embodiments, the positive electrode 12 and the negative electrode 16 act as an impermeable layer, enclosure and terminals. The positive electrode 12 and the negative electrode 16 may have a large surface area, whereby the cell 800 is capable of providing high power.

[0086] In some embodiments, predetermined sections of the adhesive 30 may be left un- heat-sealed following cell assembly for access to the interior of the cell 800 during cell formation. Unsealed sections are then sealed subsequent to cell formation.

[0087] Referring to Figs. 17 and 18, another alternative embodiment single layer cell 1000 is similar to the cell 800 illustrated in Figs. 15 and 16, and common reference numbers are used to refer to common elements. The cell 1000 illustrated in Figs. 17 and 18 is similar to the cell 800 illustrated in Figs. 15 and 16 in that the separator 14 is made the same size as the positive electrode 12 and negative electrode 16 so that a peripheral edge 14.2 of the separator 14 is aligned with the peripheral edges 12.2, 16.2 of the positive electrode 12 and negative electrode 16. In addition, a frame-shaped bead of adhesive 30 is disposed along the positive electrode clear lane 12.4 between an inner surface of the positive electrode 12 and the separator 14 and seals the positive electrode 12 to the separator 14. Another frame-shaped bead of adhesive 30 is disposed along the negative electrode clear lane 16.4 between an inner surface of the negative electrode 16 and the separator 14 and seals the negative electrode 16 to the separator 14.

[0088] The cell 1000 illustrated in Figs. 17 and 18 is different from the cell 800 illustrated in Fig. 15 and 16 in that the cell 1000 includes a flattened, first cylindrical sleeve 1002 that extends through the adhesive 30 disposed between the positive electrode 12 and the separator 14 along one edge thereof. In addition, the cell 1000 includes a flattened, second cylindrical sleeve 1004 that extends through the adhesive 30 disposed between the negative electrode 16 and the separator 14 along the same edge thereof. Although in the illustrated embodiment, the first cylindrical sleeve 1002 and the second cylindrical sleeve 1004 are disposed along the same edge, they are not limited to this configuration.

[0089] The first and second cylindrical sleeves 1002, 1004 provide access to the interior of the cell 1000 on either side of the separator 14, allowing addition of electrolyte into the cell 1000 following cell assembly, and the removal of formation gases during cell formation. The first and second cylindrical sleeves 1002, 1004 may be made from a thermoplastic that can be closed by joining the facing inner surfaces of each sleeve via heat-sealing following cell formation. Following closure of the first and second cylindrical sleeves 1002, 1004, external portions of the sleeves 1002, 1004 may be removed for example by trimming.

[0090] Referring to Figs. 19-22, another alternative embodiment single layer cell 1100 is similar to the cell 800 illustrated in Figs. 15 and 16, and common reference numbers are used to refer to common elements. The cell 1100 illustrated in Figs. 19-22 differs from the cell 800 illustrated in Figs. 15 and 16 in that the separator 14 is made to be a larger size than the positive electrode 12 and negative electrode 16 so that a peripheral edge 14.2 ofthe separator 14 extends outward beyond the peripheral edges 12.2, 16.2 of the positive electrode 12 and the negative electrode 16. In particular, the separator 14 is arranged between the positive electrode 12 and the negative electrode 16 such that it extends past the positive electrode 12 and negative electrode 16 on all sides ofthe cell 1100. This results in the separator 14 being exposed outside the cell 1100 in the areas beyond the cell perimeter. [0091] A frame-shaped bead of adhesive 30 is disposed along the positive electrode clear lane 12.4 between an inner surface of the positive electrode 12 and the separator 14 and seals the positive electrode 12 to the separator 14. Another frame-shaped bead of adhesive 30 is disposed along the negative electrode clear lane 16.4 between an inner surface of the negative electrode 16 and the separator 14 and seals the negative electrode 16 to the separator 14. The adhesive 30 intersects with the separator 14, secures the separator 14 to the positive electrode 12 and the negative electrode 16, and fills or closes the pores of the separator 14 to create a hermetic seal. In addition, the separator 14 prevents an electrical short circuit between the positive electrode 12 and the negative electrode 16.

[0092] In some embodiments, the oversized separator 14 is sealed to the positive electrode 12 and the negative electrode 16 via an adhesive that flows into and seals the pores in the separator 30.

[0093] In some embodiments, the oversized separator 14 is directly sealed to the positive electrode 12 and the negative electrode 16 via a heat sealing process in which the heat sealing process melts the separator pores closed and seals against the electrode substrates.

[0094] In the arrangement of Figs. 19-22, the separator 14 passes through and extend beyond the adhesive 30. As a result, electrical isolation between the positive electrode 12 and the negative electrode 16 is improved beyond that of the adhesive 30, and the distance to which the electrodes can creep or deform before inducing a short is increased.

[0095] Moreover, since the separator 14 is oversized, a margin 1102 of exposed separator material is provided around the perimeter 12.2, 16.2 of the positive electrode 12 and the negative electrode 16 (Fig. 21). As a result, the tolerances for placement of the separator 14 during cell assembly are greater, as un-isolated areas are avoided and slight misplacement of the separator 14 relative to the positive electrode 12 and the negative electrode 16 (Fig. 22) will not result in an electrical short circuit of the positive electrode 12 and the negative electrode 16.

[0096] Referring to Figs. 23 and 24, another alternative embodiment single layer cell 500 is similar to the cell 400 illustrated in Figs. 13 and 14, and common reference numbers are used to refer to common elements. The cell 500 illustrated in Figs. 23 and 24 differs from the cell 400 illustrated in Figs. 13 and 14 in that the electrode stack 18 is formed having an alternative peripheral shape when seen in top plan view, for example a pentagonal shape. Although a pentagonal shape is illustrated, the peripheral shape of the cell can be any polygonal shape, curved shape or combination of the two (irregularly shaped). Although the ability to provide the cell in any shape is shown with reference to the embodiment illustrated in Figs. 23 and 24, it is understood that any of the cells 10, 100, 200, 300, 400, 800, 1000, 1 100 described herein can be made having any peripheral shape when seen in top view.

[0097] In the cell 500, a bead of adhesive 30 disposed outside a periphery of the separator 14 and along the clear lanes 12.4, 16.4 seals the positive electrode 12 to the negative electrode 16 and prevents an electrical short between the positive electrode 12 and the negative electrode 16. The adhesive 30 is applied in a frame-shaped

configuration such that the positive electrode 12 and negative electrode 16 are sealed on all five sides.

[0098] Referring to Fig. 25, another alternative embodiment single layer cell 600 is similar to the cell 500 illustrated in Figs. 23 and 24, and common reference numbers are used to refer to common elements. The cell 600 illustrated in Fig. 25 differs from the cell 500 illustrated in Figs. 23 and 24 in that each layer (e.g. positive electrode 12, separator 14 and negative electrode 16) of the electrode stack 18 has an arbitrarily shaped opening 612, 614, 616 within the outer periphery of the electrode stack 18. The openings 612, 614, 616 are aligned in the stacking direction. The openings 612, 614, 616 may be used, for example, to receive a fastener (not shown) or an alignment and/or retention post (not shown). Although illustrated as being centered on the electrode stack 18, the openings 612, 614, 616 may be positioned at any location within the outer periphery of the electrode stack 18, and the positioning of the openings 612, 614, 616 is determined by the requirements of the specific application.

[0099] The cell 600 further differs from the cell 500 illustrated in Figs. 23 and 24 in that the cell 600 includes annular first and second sheets 20".1 , 20" .2 of plastic laminated metal foil. The first and second sheets 20".1 , 20" .2 are sealed on opposed outer surfaces of the cell stack. In particular, the first sheet 20".1 is disposed on one side of the stack 18 so as to overlie the opening 612 of the positive electrode 12, and the second sheet 20".2 is disposed on the opposed side of the stack 18 so as to underlie the opening 616 of the negative electrode 16. As used herein, the terms "overlie" and "underlie" are used with respect to the orientation shown in the figures, and are not intended to be limiting. The first and second sheets 20".1 , 20".2 are sized to be just larger than that of the

corresponding opening 612, 616 so that the positive electrode 12 and negative electrode 16 outward- facing sides are substantially exposed and can thus serve as terminals. The openings 22 of the first and second sheets 20".1 , 20".2 are sized to receive the fastener or post in a fitted manner. The first sheet 20".1 is sealed to both the positive electrode 12 and the fastener or post and thus seals the opening 612 on one end of the electrode stack 18, and the second sheet 20" .2 is sealed to both the negative electrode 16 and the fastener or post and thus seals the opening 616 on the opposed end of the electrode stack 18. As a result, the first and second sheets 20.1 , 20.2 serve to prevent electrolyte from leaking from the cell 600 in the vicinity of the fastener or post.

[00100] In the cell 600, a bead of adhesive 30 disposed outside a periphery of the separator 14 and along the clear lanes 12.4, 16.4 seals the positive electrode 12 to the negative electrode 16 and prevents an electrical short between the positive electrode 12 and the negative electrode 16. The adhesive 30 is applied in a frame-shaped

[00101] Referring to Fig. 26, another alternative embodiment single layer cell 700 is similar to the cell 500 illustrated in Figs. 23 and 24, and common reference numbers are used to refer to common elements. The cell 700 illustrated in Fig. 26 differs from the cell 500 illustrated in Figs. 23 and 24 in that each layer (e.g. positive electrode 12, separator 14 and negative electrode 16) of the electrode stack 18 has an arbitrarily shaped opening 612, 614, 616 that is disposed within the outer periphery of the electrode stack 18. The openings 612, 614, 616 are aligned in the stacking direction. The openings 612, 614, 616 may be used to receive a fastener (not shown) or an alignment and/or retention post (not shown). Although illustrated as being centered on the electrode stack 18, the openings 612, 614, 616 may be positioned at any location within the outer periphery of the electrode stack 18, and the positioning of the openings 612, 614, 616 is determined by the requirements of the specific application. [00102] Adhesive 30 is disposed along the outer periphery of the cell 700 between the positive electrode clear lane 12.4 and the separator 14, and between the negative electrode clear lane 16.4 and the separator 14. The adhesive 30 is applied in a pentagonal frame-shaped configuration such that the positive electrode 12 and negative electrode 16 are sealed on all five sides. In addition, adhesive 30.3 is disposed along the inner periphery of the cell 700 between the positive electrode 12 and the separator 14 at a location surrounding the corresponding openings 612, 614. In further addition, adhesive 30.3 is disposed along the inner periphery of the cell 700 between the separator 14 and the negative electrode 16 at a location surrounding the corresponding openings 614, 616. The adhesive 30.3 is applied in an annular frame-shaped configuration to match the shape of the openings 612, 614, 616. This arrangement of adhesive 30, 30.3 serves to retain the electrolyte within the cell 700, e.g., between the positive electrode 12, the negative electrode 16, the outer peripheral adhesive 30 and the inner peripheral adhesive 30.3.

[00103] Referring to Fig. 27, the single layer cells, for examples cells 400, can be arranged into a module 50 that includes a positive (+) bus bar 52, a negative (-) bus bar 54, and sensor leads S that allow monioring of the balance, temperature, current, etc. within the cell. The module 50 may also include a module housing 56. The module housing 56 is non-electrically conductive, and may formed of, for example, plastic laminated metal foil, plastic or wood. Within the module housing 56, a series electrical connection between adjacent cells is formed by placing the cells atop of one another. The electrical connection results from the direct physical contact between adjacent cells, and in some embodiments may be further enhanced by providing pressure along the stacking direction.

[00104] Referring to Fig. 28, an alternative module 150 may include many cells 400 stacked into a brick. For example, the module 150 may include 96 cells and have dimensions of 1 100 mm x 625 mm x 30 mm. The module 150 may also include a cell sensing module 152, a brace and/or bus bar 154 and composite isolators 156 formed around the periphery of the module 150.

[00105] Referring to Fig. 29, for applications in which a large cell format is not useful, it may be useful to provide alternative stack configurations. For example, in some embodiments, the cell stack may be re-oriented for example by changing from an orientation in which the stacking direction is vertical to an orientation in which the stacking direction is horizontal. In addition, or alternatively, the cells 400 may be provided in an elongated format. For example, in one embodiment, a battery pack 275 may include twenty-three modules 250, each module having 96 single layer cells in the re-oriented configuration. Such a battery pack 275 may have dimensions of about 1100mm x 690 mm 83 mm.

[00106] Referring to Figs 30-31, in some embodiments, it may be advantageous to restrain a single layer cell, for example the cell 400, within a cell stack and or a module housing. This may be achieved by, for example, punching relatively small through holes 92, 96, 94 in the respective substrates 12, 16 and separator 14 in the vicinity of the peripheral edges 12.2, 14.2, 16.2. A non-electrically conductive fastener 98 such as a bolt may be passed through the aligned through holes 92, 94, 96, securing the cells 400 to each other, and, if required, securing the stack to an external structure such as the module housing. The holes 92, 94, 96 may be sealed within each cell by conventional means, such as applying a sealing tape. Within a cell stack and or a module housing, a single fastener 98 may pass through several stacked cells 400.

[00107] Referring to Fig. 32, in some embodiments, manufacturing of the single layer cell, for example cell 400, may be similar to newsprint or sheet lamination processes in that it may be a continuous process using elongated web feed materials 1200, 1400, 1600. Such a continuous process would be possible up to the electrolyte fill step for cells having a liquid electrolyte.

[00108] Although the cells are described herein as including a liquid electrolyte, the cells are not limited to having a liquid electrolyte. For example, in some embodiments, the separator 14 and the liquid electrolyte may be replaced with a solid electrolyte such as the non-flammable solid electrolyte manufactured by SEEO of Hayward, California, under the trademark DryLyte™.

[00109] The embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling with the sprit and scope of this disclosure.

Claims

What is claimed is:

1. An electrochemical cell that comprises

a single positive electrode,

a single negative electrode, and

a separator that is disposed between the positive electrode and the negative electrode, wherein the positive electrode, the negative electrode and the separator are arranged in a stacked configuration.

2. The electrochemical cell of claim 1, wherein

the separator has the same peripheral shape and dimensions as the positive electrode and the negative electrode,

a first adhesive is disposed between a peripheral edge of the separator and a peripheral edge of the positive electrode, and

a second adhesive is disposed between a peripheral edge of the separator and a peripheral edge of the negative electrode.

3. The electrochemical cell of claim 1, wherein

the separator has a lesser dimension than the dimensions of the positive electrode and the negative electrode so that a peripheral edge of the separator resides within peripheral edges of the positive electrode and the negative electrode when the cell is viewed in top plan view,

an adhesive is disposed between a peripheral edge of the positive electrode and a peripheral edge of the negative electrode such that the positive electrode is sealed to the negative electrode, and

the adhesive surrounds a periphery of the separator.

4. The electrochemical cell of claim 1, wherein

the separator has a greater dimension than the dimensions of the positive electrode and the negative electrode so that a peripheral edge of the separator surrounds peripheral edges of the positive and negative electrodes when the cell is viewed in top plan view.

5. The electrochemical cell of claim 1 , comprising a sealing adhesive disposed between the positive electrode and the negative electrode, wherein the separator extends through the sealing material.

6. The electrochemical cell of claim 5, wherein the sealing material cooperates with the separator to provide a hermetic seal about a periphery of the cell.

7. The electrochemical cell of claim 1 , further comprising a flexible laminate housing, wherein

the positive electrode, the negative electrode and the separator are disposed in the housing, and

the housing is formed having openings that overlie each of the positive electrode and the negative electrode in such a way that outward facing surfaces of the positive electrode and the negative electrode are exposed.

8. The electrochemical cell of claim 7, wherein the flexible laminate housing comprises a first sheet of laminate material that is sealed to an outer surface of the positive electrode about a periphery of the periphery of the positive electrode, and

a second sheet of laminate material that is sealed to an outer surface of the negative electrode about a periphery of the negative electrode, and wherein

the first sheet of laminate material is sealed to the second sheet of laminate material about a periphery of the electrochemical cell.

9. The electrochemical cell of claim 7, wherein a seal is provided between each of the openings and the corresponding one of the positive electrode and the negative electrode.

10. An electrochemical cell that consists of

a single positive electrode,

a single negative electrode, a separator that is disposed between the positive electrode and the negative electrode,

an electrically isolating sealing element that joins a periphery of the positive electrode to a periphery of the negative electrode whereby the positive electrode and the negative electrode serve as a cell housing, and

an electrolyte disposed within cell housing.

11. The electrochemical cell of claim 10 wherein the positive electrode, the negative electrode and the separator are plates that are arranged in a stacked configuration.

12. A battery module comprising a plurality of electrically connected cells, where each cell includes

a single positive electrode,

a single negative electrode, and

13. The battery module of claim 12, wherein each cell of the module is electrically connected to an adjacent cell of the module, and the electrical connection is achieved by direct contact between one of the positive electrode and the negative electrode of one cell with the other of the positive electrode and the negative electrode of the adjacent cell.

14. The battery module of claim 12, wherein the separator has the same peripheral shape and dimensions as the positive electrode and the negative electrode, and a first adhesive is disposed between a peripheral edge of the separator and a peripheral edge of the positive electrode, and a second adhesive is disposed between a peripheral edge of the separator and a peripheral edge of the negative electrode.

15. The battery module of claim 12, wherein the separator has a lesser dimension than the dimensions of the positive electrode and the negative electrode so that a peripheral edge of the separator resides within peripheral edges of the positive electrode and the negative electrode when the cell is viewed in top plan view, and an adhesive is disposed between a peripheral edge of the positive electrode and a peripheral edge of the negative electrode such that the positive electrode is sealed to the negative electrode, and the adhesive surrounds a periphery of the separator.

16. The battery module of claim 12, wherein the separator has a greater dimension than the dimensions of the positive electrode and the negative electrode so that a peripheral edge of the separator surrounds peripheral edges of the positive and negative electrodes when the cell is viewed in top plan view.

17. The battery module of claim 12, comprising a sealing adhesive disposed between the positive electrode and the negative electrode, wherein the separator extends through the sealing material.

18. The battery module of claim 12, wherein each of the positive electrode, the negative electrode and the separator comprise an opening, and the openings of positive electrode, the negative electrode and the separator are aligned.

19. The battery module of claim 12, further comprising a flexible laminate housing, wherein

20. The battery module of claim 19, wherein the flexible laminate housing comprises a first sheet of laminate material that is sealed to an outer surface of the positive electrode about a periphery of the periphery of the positive electrode, and