Power storage module

Abstract

To provide a power storage module which can prevent short-circuiting.SOLUTION: A power storage module 1 comprises a positive terminal electrode 12, a bipolar electrode 11, a frame-like spacer 22 provided between the positive terminal electrode 12 and the bipolar electrode 11, and insulators 31, 32. The spacer 22 includes a communication path 221. A surface 15a includes a region 15f which is located between an outer edge 16c of a positive electrode active material layer 16 and an outer edge 15h of a collector 15, and which overlaps the communication path 221 when viewed from a Z-axis direction. A surface 15b includes a region 15g which is located between an outer edge 17c of a negative electrode active material layer 17 and the outer edge 15h of the collector 15, and which overlaps the communication path 221 when viewed from the Z-axis direction. The region 15f is provided with the insulator 31, and the region 15g is provided with the insulator 32.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a power storage module.

Background Art

[0002] A power storage module including an electrode laminate formed by laminating a plurality of electrodes is known (see, for example, Patent Document 1). The electrode laminate of such a power storage module has a first electrode and a second electrode adjacent to each other. The first electrode has a first current collector including a first surface and a first active material layer provided on the first surface, and the second electrode has a second current collector including a second surface facing the first surface and a second active material layer provided on the second surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the power storage module as described above, when a region of the first surface of the first current collector where the first active material layer is not provided comes into contact with a region of the second surface of the second current collector where the second active material layer is not provided, there is a risk of short circuit. Although it is conceivable to extend a resin member for sealing the internal space of the electrode laminate toward the first active material layer or the second active material layer, when a communication path for injecting an electrolytic solution into the internal space is formed in the resin member, there is a risk that the first current collector and the second current collector come into contact with each other through the communication path.

[0005] Also, although it is conceivable to extend the separator provided between the first active material layer and the second active material layer toward the sealing body, if foreign matter is mixed in during the injection of the electrolytic solution into the internal space, the separator may be damaged by the foreign matter, resulting in a risk that the first current collector and the second current collector come into contact with each other.

[0006] Further, when the internal space of the electrode laminate is evacuated, the first current collector located in the outermost layer of the electrode laminate tends to deform toward the second current collector due to the negative pressure in the internal space. Therefore, there is a particular demand for suppressing a short circuit caused by contact between the first current collector located in the outermost layer of the electrode laminate and the second current collector adjacent to the first current collector.

[0007] An object of the present invention is to provide a power storage module capable of suppressing a short circuit.

Means for Solving the Problems

[0008] The power storage module of the present invention includes an electrode laminate having a plurality of electrodes laminated along the stacking direction and separators provided between the plurality of electrodes, a sealing body provided on the side surface of the electrode laminate for sealing the internal space between the plurality of electrodes, an electrolytic solution accommodated in the internal space, and an insulator provided in the internal space. Among the plurality of electrodes, the first electrode located in the outermost layer of the electrode laminate in the stacking direction has a first current collector including a first surface and a first active material layer provided on the first surface. Among the plurality of electrodes, the second electrode adjacent to the first electrode has a second current collector including a second surface facing the first surface and a second active material layer provided on the second surface. The sealing body has a frame-shaped spacer provided between the first electrode and the second electrode. When viewed from the stacking direction, the outer edge of the second active material layer is located outside the outer edge of the first active material layer, and the inner edge of the spacer is located inside the outer edge of the second active material layer. The spacer includes a communication path reaching both the inner edge and the outer edge of the spacer and communicating the internal space with the outside of the electrode laminate. The first surface includes a first region located between the outer edge of the first active material layer and the outer edge of the first current collector and overlapping the communication path when viewed from the stacking direction. The second surface includes a second region located between the outer edge of the second active material layer and the outer edge of the second current collector and overlapping the communication path when viewed from the stacking direction. The insulator is provided in at least one of the first region and the second region.

[0009] In this power storage module, the inner edge of the spacer is located inside the outer edge of the second active material layer. Thereby, even if deformation of the first current collector due to evacuation of the internal space and entry of foreign matter into the internal space occur, contact between the region of the first surface where the first active material layer is not provided and the region of the second surface where the second active material layer is not provided is suppressed. Moreover, an insulator is provided in at least one of the first region of the first surface that overlaps the communication path and the second region of the second surface that overlaps the communication path. Thereby, even if deformation of the first current collector due to evacuation of the internal space and entry of foreign matter into the internal space occur, contact between the first region and the second region is suppressed. As described above, a short circuit caused by contact between the first surface and the second surface is suppressed. Therefore, according to this power storage module, a short circuit is suppressed.

[0010] In the power storage module of the present invention, the insulator may be provided over the entire first region.

[0011] In the power storage module of the present invention, the sealing body further has a sealing member provided between the first current collector and the spacer and having a frame shape surrounding the first active material layer when viewed in the stacking direction. The inner edge of the sealing member is located outside the inner edge of the spacer when viewed in the stacking direction, and the insulator may be provided in the first region between the inner edge of the spacer and the inner edge of the sealing member.

[0012] In the power storage module of the present invention, the first electrode is a positive electrode terminal electrode disposed in the outermost layer in the stacking direction of the electrode laminate, and the second electrode may be a bipolar electrode adjacent to the positive electrode terminal electrode in the electrode laminate.

[0013] In the power storage module of the present invention, the first electrode is a negative electrode terminal electrode disposed in the outermost layer in the stacking direction of the electrode laminate, and the second electrode may be a bipolar electrode adjacent to the negative electrode terminal electrode in the electrode laminate.

Advantages of the Invention

[0014] According to the present invention, it becomes possible to provide a power storage module capable of suppressing a short circuit.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions are omitted.

[0017] The power storage module 1 shown in FIG. 1 is mounted on, for example, a forklift, a hybrid vehicle, or an electric vehicle. The power storage module 1 is, for example, a nickel-metal hydride secondary battery or a lithium-ion secondary battery. The power storage module 1 may be, for example, an electric double layer capacitor. In the present embodiment, the power storage module 1 is a lithium-ion secondary battery.

[0018] As shown in FIG. 1, the power storage module 1 includes an electrode laminate 10 and a sealing body 20. The electrode laminate 10 includes a plurality of electrodes laminated along the Z-axis direction (lamination direction). The electrode laminate 10 has, for example, a rectangular parallelepiped shape. The sealing body 20 is provided on the side surface of the electrode laminate 10. The sealing body 20 seals the internal space S between the plurality of electrodes. The sealing body 20 has, for example, a rectangular tube shape. The sealing body 20 has electrical insulation.

[0019] The electrode laminate 10 has a plurality of bipolar electrodes 11, a positive terminal electrode 12, a negative terminal electrode 13, and a plurality of separators 14. The plurality of bipolar electrodes 11, the positive terminal electrode 12, the negative terminal electrode 13, and the plurality of separators 14 are laminated along the Z-axis direction.

[0020] The bipolar electrode 11 has a current collector 15, a positive electrode active material layer 16, and a negative electrode active material layer 17. The current collector 15 has, for example, a rectangular shape when viewed from the Z-axis direction. The current collector 15 includes a surface 15a and a surface 15b on the side opposite to the surface 15a. Active material layers with different polarities are provided on the surface 15a and the surface 15b of the current collector 15 of the bipolar electrode 11, respectively.

[0021] The positive electrode active material layer 16 is provided on the surface 15a. The positive electrode active material layer 16 has, for example, a rectangular shape when viewed from the Z-axis direction. The surface 15a includes an uncoated region where the positive electrode active material layer 16 is not provided. The uncoated region surrounds the positive electrode active material layer 16 when viewed from the Z-axis direction.

[0022] The negative electrode active material layer 17 is provided on the surface 15b. The negative electrode active material layer 17 has, for example, a rectangular shape when viewed from the Z-axis direction. The surface 15b includes an uncoated region where the negative electrode active material layer 17 is not provided. The uncoated region surrounds the negative electrode active material layer 17 when viewed from the Z-axis direction.

[0023] The plurality of bipolar electrodes 11 are laminated such that the positive electrode active material layer 16 of one bipolar electrode 11 faces the negative electrode active material layer 17 of another bipolar electrode 11. That is, the plurality of bipolar electrodes 11 are laminated such that, among adjacent bipolar electrodes 11, the surface 15a of the current collector 15 of one bipolar electrode 11 faces the surface 15b of the current collector 15 of the other bipolar electrode 11.

[0024] The positive terminal electrode 12 is disposed on one side in the Z-axis direction with respect to the plurality of bipolar electrodes 11. The positive terminal electrode 12 is located in the outermost layer (one end) of the electrode laminate 10 in the Z-axis direction. The positive terminal electrode 12 has a current collector 15 and a positive electrode active material layer 16. The positive terminal electrode 12 is mainly different from the bipolar electrode 11 in that it does not have a negative electrode active material layer 17. That is, a positive electrode active material layer 16 is provided on the surface 15a of the current collector 15 of the positive terminal electrode 12, and no active material layer is provided on the surface 15b of the current collector 15 of the positive terminal electrode 12. Other configurations of the positive terminal electrode 12 may be the same as those of the bipolar electrode 11. The positive electrode active material layer 16 of the positive terminal electrode 12 faces the negative electrode active material layer 17 of the bipolar electrode 11. That is, the positive terminal electrode 12 is laminated such that the surface 15a of the current collector 15 of the positive terminal electrode 12 and the surface 15b of the current collector 15 of the bipolar electrode 11 adjacent to the positive terminal electrode 12 face each other.

[0025] The negative terminal electrode 13 is disposed on the other side in the Z-axis direction with respect to the plurality of bipolar electrodes 11. The negative terminal electrode 13 is located in the outermost layer (the other end) of the electrode laminate 10 in the Z-axis direction. The negative terminal electrode 13 has a current collector 15 and a negative electrode active material layer 17. The negative terminal electrode 13 is mainly different from the bipolar electrode 11 in that it does not have a positive electrode active material layer 16. That is, a negative electrode active material layer 17 is provided on the surface 15b of the current collector 15 of the negative terminal electrode 13, and no active material layer is provided on the surface 15a of the current collector 15 of the negative terminal electrode 13. Other configurations of the negative terminal electrode 13 may be the same as those of the bipolar electrode 11. The negative electrode active material layer 17 of the negative terminal electrode 13 faces the positive electrode active material layer 16 of the bipolar electrode 11. That is, the negative terminal electrode 13 is laminated such that the surface 15b of the current collector 15 of the negative terminal electrode 13 and the surface 15a of the current collector 15 of the bipolar electrode 11 adjacent to the negative terminal electrode 13 face each other.

[0026] The outer edges of the current collectors 15 of the electrodes 11, 12, and 13 form the side surfaces of the electrode stack 10. Between each of the bipolar electrodes 11, between the bipolar electrode 11 and the positive terminal electrode 12, and between the bipolar electrode 11 and the negative terminal electrode 13, internal spaces S for accommodating an electrolyte are formed.

[0027] The separator 14 is disposed between each bipolar electrode 11, between the bipolar electrode 11 and the positive electrode terminal electrode 12, and between the bipolar electrode 11 and the negative electrode terminal electrode 13. The separator 14 is disposed between the positive electrode active material layer 16 and the negative electrode active material layer 17 facing each other. The separator 14 is, for example, sheet-shaped. When viewed from the Z-axis direction, the outer edge of the separator 14 is located outside the outer edge of the positive electrode active material layer 16 and the outer edge of the negative electrode active material layer 17. The separator 14 allows charge carriers such as lithium ions to pass through. The separator 14 separates the adjacent electrodes 11, 12, and 13. This prevents electrical short circuits caused by contact between the electrodes 11, 12, and 13. The separator 14 absorbs and retains the electrolyte.

[0028] The current collector 15 has a function of maintaining the flow of current in the positive electrode active material layer 16 and the negative electrode active material layer 17 during discharging or charging of the storage module 1. The current collector 15 is, for example, a chemically inactive electrical conductor. The material of the current collector 15 is, for example, a metal material, a conductive resin material, a conductive inorganic material, etc. The conductive resin material is, for example, a conductive polymer material, or a non-conductive polymer material to which a conductive filler is added, etc. When the current collector 15 has a plurality of layers, the material of each layer may be any of the materials described above. A coating layer may be formed on the surface of the current collector 15. The coating layer may be formed by a known method such as plating or spray coating.

[0029] The current collector 15 exhibits, for example, a plate shape, foil shape, sheet shape, film shape, mesh shape, or the like. The current collector 15 may be, for example, aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil. The current collector 15 may be an alloy foil or clad foil of the above metals. When the current collector 15 is in the form of foil, the thickness of the current collector 15 is, for example, 1 μm or more and 100 μm or less. The current collector 15 may be a laminate having a plurality of metal layers. The current collector 15 may be, for example, a laminate in which an aluminum layer and a copper layer are integrated. The current collector 15 may include, for example, aluminum foil and copper plating formed on one side of the aluminum foil. The current collector 15 may include a plurality of metal foils adhered by a conductive adhesive.

[0030] The positive electrode active material layer 16 contains a positive electrode active material capable of occluding and releasing charge carriers such as lithium ions. The positive electrode active material is, for example, a composite oxide, lithium metal, sulfur, or the like. The composite oxide contains, for example, at least one of iron, manganese, titanium, nickel, cobalt, and aluminum and lithium. The composite oxide is olivine-type lithium iron phosphate (LiFePO4), LiCoO2, LiNiMnCoO2, or the like.

[0031] The negative electrode active material layer 17 contains a negative electrode active material capable of occluding and releasing charge carriers such as lithium ions. The negative electrode active material is, for example, graphite, artificial graphite, highly oriented graphite, mesocarbon microbeads, hard carbon, soft carbon, a metal compound, an element capable of alloying with lithium or a compound thereof, boron-added carbon, or the like. The element capable of alloying with lithium is, for example, silicon or tin.

[0032] Each of the positive electrode active material layer 16 and the negative electrode active material layer 17 may contain, in addition to the active material, a binder and a conductive assistant. The binder has a function of connecting the active material or the conductive assistant to each other and maintaining the conductive network in the electrode. Examples of the binder include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide resins such as polyimide and polyamideimide, alkoxysilyl group-containing resins, acrylic resins such as polyacrylic acid and polymethacrylic acid, styrene-butadiene rubber, carboxymethyl cellulose, alginates such as sodium alginate and ammonium alginate, water-soluble cellulose ester cross-linked products, starch-acrylic acid graft polymers, and the like. These binders can be used alone or in combination. The conductive assistant is a conductive material and has a function of enhancing electrical conductivity. Examples of the conductive assistant include acetylene black, carbon black, graphite, and the like. The viscosity-adjusting solvent is, for example, N-methyl-2-pyrrolidone or the like.

[0033] For the formation of the positive electrode active material layer 16 on the surface 15a and the formation of the negative electrode active material layer 17 on the surface 15b, conventionally known methods such as a roll coating method, a die coating method, a dip coating method, a doctor blade method, a spray coating method, and a curtain coating method are used. Specifically, the active material, the solvent, and, if necessary, the binder and the conductive assistant are mixed to produce a slurry-like composition for forming the active material layer, and after the composition for forming the active material layer is applied to the surface 15a or the surface 15b, it is dried. Examples of the solvent include N-methyl-2-pyrrolidone, methanol, methyl isobutyl ketone, and water. In order to increase the electrode density, the dried product may be compressed.

[0034] The electrolyte is housed in the internal space S. The electrolyte is impregnated in the separator 14. The electrolyte is, for example, a liquid containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The electrolyte salt of the electrolyte is, for example, a known lithium salt such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, LiN(CF3SO2)2, etc. The non-aqueous solvent is cyclic carbonates, cyclic esters, chain carbonates, chain esters, ethers, etc. Note that two or more of these known solvent materials may be used in combination.

[0035] The sealing body 20 has a seal member 21, a spacer 22, and a welded portion 23. The seal member 21, for example, has a rectangular frame shape. The seal member 21 covers the outer peripheral portion 15c of each current collector 15. The seal member 21 is provided on the surface 15a and the surface 15b of each current collector 15. The seal member 21 provided on the current collector 15 of the bipolar electrode 11 is located between adjacent spacers 22. The portion of the seal member 21 provided on the surface 15a of the current collector 15 of the positive terminal electrode 12 is located between the current collector 15 and the spacer 22 adjacent to the current collector 15. The portion of the seal member 21 provided on the surface 15b of the current collector 15 of the negative terminal electrode 13 is located between the current collector 15 and the spacer 22 adjacent to the current collector 15. The seal member 21 surrounds the positive electrode active material layer 16 and the negative electrode active material layer 17 when viewed from the Z-axis direction. The seal member 21 is welded to the current collector 15.

[0036] The spacer 22 has, for example, a rectangular frame shape. The spacer 22 is provided between a pair of bipolar electrodes 11 adjacent to each other, between the positive terminal electrode 12 and the bipolar electrode 11 adjacent to the positive terminal electrode 12, and between the negative terminal electrode 13 and the bipolar electrode 11 adjacent to the negative terminal electrode 13. The spacer 22 is provided between the seal members 21 adjacent to each other. The spacer 22 is sandwiched by the seal members 21 adjacent to each other. When viewed from the Z-axis direction, the inner edge of the spacer 22 is located inside the outer edge of the negative electrode active material layer 17. When viewed from the Z-axis direction, the inner edge of the spacer 22 is located outside the outer edge of the positive electrode active material layer 16. When viewed from the Z-axis direction, the inner peripheral portion of the spacer 22 overlaps the negative electrode active material layer 17. The inner peripheral portion of the spacer 22 is located between the surface 15a of the current collector 15 and the negative electrode active material layer 17.

[0037] The spacer 22, together with a pair of seal members 21 adjacent to each other, holds the interval between the current collectors 15 adjacent to each other. The internal space S is defined by a pair of current collectors 15, the spacer 22, and a pair of seal members 21. The welded portion 23 is integrated by welding the outer peripheral portions of each seal member 21 and the outer peripheral portions of each spacer 22. The welded portion 23 has, for example, a rectangular tubular shape.

[0038] The outer peripheral portion of the separator 14 may be sandwiched and held between the seal member 21 and the spacer 22. The separator 14 can be fixed by being welded to at least one of the seal member 21 and the spacer 22.

[0039] The materials of each of the seal member 21 and the spacer 22 are, for example, acid-modified polyethylene (acid-modified PE), acid-modified polypropylene (acid-modified PP), polyethylene, or polypropylene, etc. Each of the seal member 21 and the spacer 22 has electrolyte resistance. The materials of each of the seal member 21 and the spacer 22 may be the same or different from each other. In the present embodiment, the material of the seal member 21 is, for example, acid-modified polyethylene or acid-modified polypropylene. In the present embodiment, the material of the spacer 22 is, for example, polyethylene or polypropylene. Acid-modified polyethylene and acid-modified polypropylene are easier to bond to metal compared to non-acid-modified polyethylene and non-acid-modified polypropylene. When the current collector 15 is made of metal, by forming the seal member 21 from acid-modified polyethylene or acid-modified polypropylene, the bonding strength of the seal member 21 to the current collector 15 can be improved.

[0040] Since the thicknesses of the positive electrode active material layer 16 and the negative electrode active material layer 17 provided between a pair of adjacent current collectors 15 are larger than the thicknesses of the seal member 21 and the spacer 22 provided between the pair of adjacent current collectors 15, the thickness of the region of the power storage module 1 including the positive electrode active material layer 16 and the negative electrode active material layer 17 is larger than the thickness of the region of the power storage module 1 including the sealing body 20. The region of the power storage module 1 including the positive electrode active material layer 16 and the negative electrode active material layer 17 protrudes to one side in the Z-axis direction with respect to the region of the power storage module 1 including the sealing body 20. In the present embodiment, the surface 15b of the current collector 15 of the positive electrode terminal electrode 12 protrudes more than one end surface of the sealing body 20 in the Z-axis direction, and the surface 15a of the current collector 15 of the negative electrode terminal electrode 13 is substantially flush with the other end surface of the sealing body 20 in the Z-axis direction.

[0041] In this embodiment, the positive electrode terminal electrode 12 is the first electrode, the bipolar electrode 11 adjacent to the positive electrode terminal electrode 12 is the second electrode, the current collector 15 of the positive electrode terminal electrode 12 is the first current collector, the current collector 15 of the bipolar electrode 11 is the second current collector, the surface 15a of the current collector 15 of the positive electrode terminal electrode 12 is the first surface, the positive electrode active material layer 16 provided on the surface 15a of the current collector 15 of the positive electrode terminal electrode 12 is the first active material layer, the surface 15b of the current collector 15 of the bipolar electrode 11 is the second surface, and the negative electrode active material layer 17 provided on the surface 15b of the current collector 15 of the bipolar electrode 11 is the second active material layer.

[0042] FIG. 2 is a cross-sectional view of the positive electrode terminal electrode (first electrode) 12 and the bipolar electrode (second electrode) 11 adjacent to the positive electrode terminal electrode 12. FIG. 3 is a bottom view of the positive electrode terminal electrode 12 and the spacer 22 when viewed from the surface 15a side of the current collector 15 of the positive electrode terminal electrode 12 shown in FIG. 2.

[0043] As shown in FIGS. 2 and 3, when viewed from the Z-axis direction, the outer edge 17c of the negative electrode active material layer 17 is located outside the outer edge 16c of the positive electrode active material layer 16. That is, when viewed from the Z-axis direction, the area of the negative electrode active material layer 17 is larger than the area of the positive electrode active material layer 16.

[0044] When viewed from the Z-axis direction, the inner edge 21c of the seal member 21 is located outside each of the outer edge 16c of the positive electrode active material layer 16 and the outer edge 17c of the negative electrode active material layer 17. When viewed from the Z-axis direction, the inner edge 22c of the spacer 22 is located inside the inner edge 21c of the seal member 21. In other words, when viewed from the Z-axis direction, the inner edge 21c of the seal member 21 is located outside the inner edge 22c of the spacer 22. When viewed from the Z-axis direction, the inner edge 22c of the spacer 22 is located inside the outer edge 17c of the negative electrode active material layer 17. When viewed from the Z-axis direction, the inner edge 22c of the spacer 22 is located outside the outer edge 16c of the positive electrode active material layer 16. When viewed from the Z-axis direction, the inner peripheral portion of the spacer 22 overlaps the negative electrode active material layer 17. The inner peripheral portion of the spacer 22 is located between the surface 15a of the current collector 15 and the negative electrode active material layer 17.

[0045] The spacer 22 includes a communication path 221. The communication path 221 reaches both the inner edge 22c and the outer edge of the spacer 22. The communication path 221 opens to each of the inner edge 22c of the spacer 22 and the outer surface of the sealing body 20. The communication path 221 communicates with the internal space S (see FIG. 1). The communication path 221 communicates the internal space S with the outside of the electrode laminate 10. In the present embodiment, the communication path 221 penetrates the spacer 22 in the Z-axis direction (the thickness direction of the spacer 22). The communication path 221 functions as a path for injecting an electrolytic solution into the internal space S. When viewed from the Z-axis direction, the communication path 221 overlaps with the uncoated region 15d of the surface 15a of the current collector 15 of the positive terminal electrode 12 and the uncoated region 15e of the surface 15b of the current collector 15 of the bipolar electrode 11, respectively.

[0046] The power storage module 1 further includes an insulator 31 and an insulator 32. The insulators 31 and 32 are provided in the internal space S. The insulators 31 and 32 are provided between the surface 15a of the current collector 15 of the positive terminal electrode 12 and the surface 15b of the current collector 15 of the bipolar electrode 11. In the present embodiment, the insulator 31 is provided on the surface 15a of the current collector 15 of the positive terminal electrode 12. Specifically, the surface 15a of the current collector 15 of the positive terminal electrode 12 includes a region (first region) 15f located outside the outer edge 16c of the positive electrode active material layer 16. In the present embodiment, the region 15f is a side portion that overlaps the communication path 221 among the side portions of the uncoated region 15d. The region 15f is located between the outer edge 16c of the positive electrode active material layer 16 and the outer edge 15h of the current collector 15. The region 15f has, for example, a rectangular shape. Both ends of the region 15f in the X-axis direction reach the outer edge 16c of the positive electrode active material layer 16 and the inner edge 21c of the seal member 21, respectively. Both ends of the region 15f in the Y-axis direction reach the inner edge 21c of the seal member 21.

[0047] The insulator 31 is provided between the inner edge 22c of the spacer 22 and the outer edge 15h of the current collector 15 (region R shown in FIG. 2). The insulator 31 is provided in region 15f between the inner edge 22c of the spacer 22 and the inner edge 21c of the seal member 21. When viewed from the Z-axis direction, the outer edge of the insulator 31 is located outside the communication path 221. The insulator 31 extends along the inner edge 22c of the spacer 22 in a state of overlapping the communication path 221 and straddling the communication path 221 when viewed from the Z-axis direction. The insulator 31 is provided over the entire region 15f. The insulator 31 covers the entire region 15f. In the present embodiment, the insulator 31 is an insulating layer provided in region 15f. The insulator 31 is coated on region 15f. The insulator 31 has electrical insulation properties. The material of the insulator 31 is, for example, a resin such as polyethylene (PE), polypropylene (PP), polyamideimide (PAI), polytetrafluoroethylene (PTFE), or a rubber such as silicone rubber. The insulator 31 may be formed of a non-conductive material.

[0048] FIG. 4 is a plan view of the bipolar electrode 11 shown in FIG. 2. As shown in FIGS. 2 and 4, the insulator 32 is provided on the surface 15b of the current collector 15 of the bipolar electrode 11. Specifically, the surface 15b of the current collector 15 of the bipolar electrode 11 includes a region (second region) 15g that is located outside the outer edge 17c of the negative electrode active material layer 17. In the present embodiment, region 15g is the side portion that overlaps the communication path 221 among the side portions of the uncoated region 15e. Region 15g is located between the outer edge 17c of the negative electrode active material layer 17 and the outer edge 15h of the current collector 15. Region 15g has, for example, a rectangular shape. Both ends of region 15g in the X-axis direction reach the outer edge 17c of the negative electrode active material layer 17 and the inner edge 21c of the seal member 21, respectively. Both ends of region 15g in the Y-axis direction reach the inner edge 21c of the seal member 21.

[0049] The insulator 32 is provided in the region 15g between the inner edge 22c of the spacer 22 and the inner edge 21c of the seal member 21. When viewed from the Z-axis direction, the outer edge of the insulator 32 is located outside the communication path 221. The insulator 32 extends along the inner edge 22c of the spacer 22 in a state of overlapping the communication path 221 and straddling the communication path 221 when viewed from the Z-axis direction. The insulator 32 is provided over the entire region 15g. The insulator 32 covers the entire region 15g. In the present embodiment, the insulator 32 is an insulating layer provided in the region 15g. The insulator 32 is coated on the region 15g. The insulator 32 has electrical insulation properties. The material of the insulator 32 is, for example, a resin such as polyethylene (PE), polypropylene (PP), polyamideimide (PAI), polytetrafluoroethylene (PTFE), or a rubber such as silicone rubber. The insulator 32 may be formed of a non-conductive material. Thus, in the present embodiment, insulators 31 and 32 are provided between the region 15f overlapping the communication path 221 and the region 15g when viewed from the Z-axis direction.

[0050] FIG. 5 is a cross-sectional view of the negative terminal electrode 13 and the bipolar electrode 11 adjacent to the negative terminal electrode 13. FIG. 6 is a bottom view of the bipolar electrode 11 and the spacer 22 when viewed from the surface 15a side of the current collector 15 of the bipolar electrode 11 shown in FIG. 5.

[0051] As shown in FIGS. 5 and 6, insulators 31 and 32 are also provided between the surface 15a of the current collector 15 of the bipolar electrode 11 and the surface 15b of the current collector 15 of the negative terminal electrode 13. In the present embodiment, the insulator 31 is provided on the surface 15a of the current collector 15 of the bipolar electrode 11. Specifically, the surface 15a of the current collector 15 of the bipolar electrode 11 includes a region (first region) 15f located outside the outer edge 16c of the positive electrode active material layer 16, similar to the surface 15a of the current collector 15 of the positive terminal electrode 12. An insulator 31 is also provided in the region 15f of the bipolar electrode 11, similar to the region 15f of the positive terminal electrode 12.

[0052] FIG. 7 is a plan view of the negative terminal electrode 13 shown in FIG. 5. As shown in FIGS. 5 and 7, the insulator 32 is provided on the surface 15b of the current collector 15 of the negative terminal electrode 13. Specifically, the surface 15b of the current collector 15 of the negative terminal electrode 13 includes a region (second region) 15g located outside the outer edge 17c of the negative electrode active material layer 17, similar to the surface 15b of the current collector 15 of the bipolar electrode 11. An insulator 32 is also provided in the region 15g of the negative terminal electrode 13, similar to the region 15g of the bipolar electrode 11.

[0053] As described above, in the power storage module 1, the inner edge 22c of the spacer 22 is located inside the outer edge 17c of the negative electrode active material layer 17. Thus, even if deformation of the current collector 15 of the positive terminal electrode 12 and entry of foreign matter into the internal space S due to evacuation of the internal space S occur, contact between the region (uncoated region 15d) of the surface 15a of the current collector 15 of the positive terminal electrode 12 where the positive electrode active material layer 16 is not provided and the region (uncoated region 15e) of the surface 15b of the current collector 15 of the bipolar electrode 11 where the negative electrode active material layer 17 is not provided is suppressed. Moreover, an insulator 31 is provided in the region 15f of the surface 15a that overlaps with the communication path 221, and an insulator 32 is provided in the region 15g of the surface 15b that overlaps with the communication path 221. Thus, even if deformation of the current collector 15 of the positive terminal electrode 12 and entry of foreign matter into the internal space S due to evacuation of the internal space S occur, contact between the region 15f and the region 15g is suppressed. As a result, a short circuit caused by contact between the surface 15a of the current collector 15 of the positive terminal electrode 12 and the surface 15b of the current collector 15 of the bipolar electrode 11 is suppressed. Therefore, according to the power storage module 1, a short circuit is suppressed. Since the separator 14 exists between the current collector 15 of the positive terminal electrode 12 and the current collector 15 of the bipolar electrode 11, contact between the current collectors 15 is suppressed. However, for example, when foreign matter or the like exists between the current collector 15 of the positive terminal electrode 12 and the current collector 15 of the bipolar electrode 11, the separator 14 may be damaged by the foreign matter, and in that case, contact between the current collectors 15 may occur. According to the power storage module 1, damage to the current collector 15 caused by contact with foreign matter is suppressed.

[0054] The insulator 31 is provided over the entire region 15f. This reliably suppresses a short circuit resulting from contact between the current collector 15 of the positive terminal electrode 12 and the current collector 15 of the bipolar electrode 11.

[0055] The sealing body 20 has a seal member 21 provided between the current collector 15 and the spacer 22 and having a frame shape that surrounds the positive electrode active material layer 16 when viewed from the Z-axis direction. The inner edge 21c of the seal member 21 is located outside the inner edge 22c of the spacer 22 when viewed from the Z-axis direction. The insulator 31 is provided in the region 15f between the inner edge 22c of the spacer 22 and the inner edge 21c of the seal member 21. This reliably suppresses a short circuit resulting from contact between the current collector 15 of the positive terminal electrode 12 and the current collector 15 of the bipolar electrode 11.

[0056] The positive terminal electrode 12 is an electrode disposed in the outermost layer in the Z-axis direction of the electrode laminate 10. The bipolar electrode 11 is an electrode adjacent to the positive terminal electrode 12 in the electrode laminate 10. This suppresses a short circuit between the positive terminal electrode 12 and the bipolar electrode 11.

[0057] In the power storage module 1, the insulator 31 is an insulating layer provided in the region 15f, and the insulator 32 is an insulating layer provided in the region 15g. This suitably suppresses a short circuit resulting from contact between the region 15f and the region 15g, and suitably suppresses foil breakage resulting from contact between the region 15f and the region 15g with a foreign object.

[0058] In the power storage module 1, the insulators 31 and 32 extend along the inner edge 22c of the spacer 22 in a state of straddling the communication path 221 when viewed from the Z-axis direction. This suitably suppresses a short circuit resulting from contact between the region 15f and the region 15g, and reliably suppresses foil breakage resulting from contact between the region 15f and the region 15g with a foreign object.

[0059] In the storage module 1, since the positive terminal electrode 12 is disposed on the outermost layer of the electrode laminate 10, when the internal space S between the positive terminal electrode 12 and the bipolar electrode 11 is depressurized, the current collector 15 of the positive terminal electrode 12 may be deformed. Here, a spacer 22 is provided between the positive terminal electrode 12 and the bipolar electrode 11, and insulators 31 and 32 are provided between the region 15f of the current collector 15 of the positive terminal electrode 12 and the region 15g of the current collector 15 of the bipolar electrode 11. Therefore, even if the current collector 15 of the positive terminal electrode 12 is deformed, the contact between the surface 15a of the current collector 15 of the positive terminal electrode 12 and the surface 15b of the current collector 15 of the bipolar electrode 11 is suppressed, and foil breakage caused by the contact of the surface 15a of the current collector 15 of the positive terminal electrode 12 and the surface 15b of the current collector 15 of the bipolar electrode 11 with foreign matter is suppressed. As a result, a short circuit caused by the contact between the surface 15a and the surface 15b is suppressed.

[0060] As described above, in the present embodiment, since the inside of the power storage module 1 is depressurized with respect to atmospheric pressure, the region including the positive electrode active material layer 16 and the negative electrode active material layer 17 in the power storage module 1 protrudes to one side in the Z-axis direction with respect to the region including the sealing body 20 in the power storage module 1, and the surface 15b of the current collector 15 of the positive electrode terminal electrode 12 protrudes more than one end surface of the sealing body 20 in the Z-axis direction. Therefore, the amount of deformation of the current collector 15 of the positive electrode terminal electrode 12 is larger than the amount of deformation of the current collector 15 of the negative electrode terminal electrode 13 or the current collector 15 of the bipolar electrode 11. When the inside of the power storage module 1 is depressurized with respect to atmospheric pressure as described above, the current collector 15 of the positive electrode terminal electrode 12 and the current collector 15 of the bipolar electrode 11 tend to come into contact more easily than the current collector 15 of the negative electrode terminal electrode 13 and the current collector 15 of the bipolar electrode 11. Further, in the present embodiment, the outer edge 17c of the negative electrode active material layer 17 is located outside the outer edge 16c of the positive electrode active material layer 16. That is, the uncoated region 15d of the current collector 15 of the positive electrode terminal electrode 12 is wider than the uncoated region 15e of the current collector 15 of the negative electrode terminal electrode 13. Therefore, the current collector 15 of the positive electrode terminal electrode 12 tends to deform more easily in a state where the inside of the power storage module 1 is depressurized with respect to atmospheric pressure than the current collector 15 of the negative electrode terminal electrode 13. For these reasons, it is extremely important to suppress a short circuit caused by deformation of the current collector 15 of the positive electrode terminal electrode 12.

[0061] In the power storage module 1, since the negative electrode terminal electrode 13 is disposed on the outermost layer of the electrode laminate 10, when the internal space S between the negative electrode terminal electrode 13 and the bipolar electrode 11 is depressurized, the current collector 15 of the negative electrode terminal electrode 13 may deform. Here, since the spacer 22 is provided between the negative electrode terminal electrode 13 and the bipolar electrode 11 and the insulators 31 and 32 are provided between the region 15g of the current collector 15 of the negative electrode terminal electrode 13 and the region 15f of the current collector 15 of the bipolar electrode 11, even if the current collector 15 of the negative electrode terminal electrode 13 deforms, contact between the surface 15b of the current collector 15 of the negative electrode terminal electrode 13 and the surface 15a of the current collector 15 of the bipolar electrode 11 is suppressed. As a result, a short circuit caused by contact between the surface 15a and the surface 15b is suppressed, and foil breakage caused by contact between the surface 15a and the surface 15b with foreign matter is suppressed.

[0062] As described above, one embodiment of the present invention has been explained. However, the present invention is not limited to the above-described embodiment.

[0063] FIG. 8 is a cross-sectional view of a power storage module according to a first modified example. As shown in FIG. 8, the communication path 221 of the spacer 22 may not penetrate the spacer 22 in the Z-axis direction. The communication path 221 may not open to, for example, any one of two surfaces of the spacer 22 that face opposite sides in the Z-axis direction. That is, the spacer 22 may have a bottom wall portion 222. The bottom wall portion 222 overlaps the communication path 221 when viewed from the Z-axis direction. In this case, the bottom wall portion 222 functions as an insulator. In such a case, the power storage module 1 may or may not have insulators 31 and 32. Note that the bottom wall portion 222 may be integrally formed with the main body portion of the spacer 22 or may be separately formed from the main body portion of the spacer 22.

[0064] FIG. 9 is a cross-sectional view of a power storage module according to a second modified example. FIG. 10 is a bottom view of the positive terminal electrode 12 and the spacer 22 when viewed from the surface 15a side of the current collector 15 of the positive terminal electrode 12 shown in FIG. 9. As shown in FIGS. 9 and 10, the seal member 21 may have a protruding portion 212 in addition to the main body portion 211.

[0065] The body portion 211 is an area provided on the outer peripheral portion 15c of the current collector 15 among the seal members 21. The body portion 211 has a rectangular frame shape, similar to the seal member 21 of the embodiment. The protruding portion 212 protrudes from the inner edge 21c of the body portion 211 toward the inside of the seal member 21. The protruding portion 212 is provided on the surface 15a of the current collector 15. When viewed from the Z-axis direction, the protruding portion 212 overlaps with the communication path 221 of the spacer 22. When viewed from the Z-axis direction, the inner edge 21d of the protruding portion 212 coincides with the inner edge 22c of the spacer 22. When viewed from the Z-axis direction, both ends of the protruding portion 212 in the Y-axis direction are located outside the communication path 221. In such a case, the power storage module 1 may or may not have the insulators 31 and 32. Note that the body portion 211 and the protruding portion 212 of the seal member 21 may be integrally formed or separately formed. Also, the protruding portion 212 may be provided on the surface 15b of the current collector 15 or may be provided on both the surface 15a and the surface 15b of the current collector 15.

[0066] As shown in FIGS. 8 to 10, it is sufficient that an insulator is provided between at least the region (first region) of the surface 15a of one current collector (first current collector) 15 that overlaps with the communication path 221 and the region (second region) of the surface 15b of the other current collector (second current collector) 15 that overlaps with the communication path 221. An insulator may or may not be provided between the region of the surface 15a of one current collector 15 that does not overlap with the communication path 221 and the region of the surface 15b of the other current collector 15 that does not overlap with the communication path 221.

[0067] In the embodiment, the power storage module 1 includes both the insulator 31 and the insulator 32. However, the power storage module 1 may not include either one of the insulator 31 and the insulator 32. For example, when the insulator 31 is provided on the positive terminal electrode 12, the insulator 32 may not be provided on the bipolar electrode 11. The insulators 31 and 32 may also be provided on the bipolar electrodes 11 other than the bipolar electrode 11 adjacent to the positive terminal electrode 12 and the bipolar electrode 11 adjacent to the negative terminal electrode 13.

[0068] In the embodiment, the positive terminal electrode 12 is the first electrode, and the bipolar electrode 11 adjacent to the positive terminal electrode 12 is the second electrode. However, the negative terminal electrode 13 may be the first electrode, and the bipolar electrode 11 adjacent to the negative terminal electrode 13 may be the second electrode.

[0069] In the embodiment, the positive electrode active material layer 16 is the first active material layer and the negative electrode active material layer 17 is the second active material layer. However, the negative electrode active material layer 17 may be the first active material layer and the positive electrode active material layer 16 may be the second active material layer.

[0070] The gist of the present disclosure is as follows [1] to [5]. [1] An electrode laminate having a plurality of electrodes laminated along a stacking direction and a separator provided between the plurality of electrodes, a sealing body provided on a side surface of the electrode laminate for sealing an internal space between the plurality of electrodes, an electrolytic solution accommodated in the internal space, and an insulator provided in the internal space. Among the plurality of electrodes, a first electrode located at the outermost layer of the electrode laminate in the stacking direction has a first current collector including a first surface and a first active material layer provided on the first surface. Among the plurality of electrodes, a second electrode adjacent to the first electrode has a second current collector including a second surface facing the first surface and a second active material layer provided on the second surface. The sealing body has a frame-shaped spacer provided between the first electrode and the second electrode. When viewed from the stacking direction, an outer edge of the second active material layer is located outside an outer edge of the first active material layer and an inner edge of the spacer is located inside the outer edge of the second active material layer. The spacer includes a communication path reaching both an inner edge and an outer edge of the spacer and communicating the internal space with the outside of the electrode laminate. The first surface includes a first region located between an outer edge of the first active material layer and an outer edge of the first current collector and overlapping the communication path when viewed from the stacking direction. The second surface includes a second region located between an outer edge of the second active material layer and an outer edge of the second current collector and overlapping the communication path when viewed from the stacking direction. The insulator is provided in at least one of the first region and the second region. A power storage module. [2] The power storage module according to [1] above, wherein the insulator is provided over the entire first region. [3] The sealing body further has a seal member provided between the first current collector and the spacer and having a frame shape surrounding the first active material layer when viewed from the stacking direction. An inner edge of the seal member is located outside an inner edge of the spacer when viewed from the stacking direction. The insulator is provided in the first region between the inner edge of the spacer and the inner edge of the seal member. The power storage module according to [1] or [2] above. [4] The first electrode is a positive terminal electrode disposed in the outermost layer in the stacking direction of the electrode laminate, and the second electrode is a bipolar electrode adjacent to the positive terminal electrode in the electrode laminate. The power storage module according to any one of [1] to [3] above. [5] The first electrode is a negative terminal electrode disposed in the outermost layer in the stacking direction of the electrode laminate, and the second electrode is a bipolar electrode adjacent to the negative terminal electrode in the electrode laminate. The power storage module according to any one of [1] to [3] above.

Description of symbols

[0071] 1... Power storage module, 11... Bipolar electrode, 12... Positive terminal electrode, 13... Negative terminal electrode, 15... Current collector, 15a... Surface (first surface), 15b... Surface (second surface), 15f... Region (first region), 15g... Region (second region), 16... Positive electrode active material layer (first active material layer), 17... Negative electrode active material layer (second active material layer), 22... Spacer, 31, 32... Insulator, 221... Communication path.

Claims

1. An electrode laminate having a plurality of electrodes laminated along a stacking direction, and a separator provided between the plurality of electrodes; A sealing body provided on a side surface of the electrode laminate for sealing an internal space between the plurality of electrodes; An electrolytic solution accommodated in the internal space; An insulator provided in the internal space, and comprising: Among the plurality of electrodes, a first electrode located in the outermost layer of the electrode laminate in the stacking direction has a first current collector including a first surface, and a first active material layer provided on the first surface; Among the plurality of electrodes, a second electrode adjacent to the first electrode has a second current collector including a second surface facing the first surface, and a second active material layer provided on the second surface; The sealing body has a frame-shaped spacer provided between the first electrode and the second electrode; When viewed from the stacking direction, an outer edge of the second active material layer is located outside an outer edge of the first active material layer, and an inner edge of the spacer is located inside the outer edge of the second active material layer; The spacer includes a communication path reaching both an inner edge and an outer edge of the spacer and communicating the internal space with the outside of the electrode laminate; The first surface is located between an outer edge of the first active material layer and an outer edge of the first current collector, and includes a first region overlapping the communication path when viewed from the stacking direction; The second surface is located between an outer edge of the second active material layer and an outer edge of the second current collector, and includes a second region overlapping the communication path when viewed from the stacking direction; The insulator is provided in at least one of the first region and the second region, a power storage module.

2. The insulator is provided over the entire first region, the power storage module according to claim 1.

3. The sealing body further has a seal member provided between the first current collector and the spacer and having a frame shape surrounding the first active material layer when viewed from the stacking direction; An inner edge of the seal member is located outside an inner edge of the spacer when viewed from the stacking direction; The insulator is provided in the first region between an inner edge of the spacer and an inner edge of the seal member, the power storage module according to claim 1.

4. The first electrode is a positive terminal electrode disposed in the outermost layer of the electrode laminate in the stacking direction, The storage module according to claim 1, wherein the second electrode is a bipolar electrode adjacent to the positive terminal electrode in the electrode laminate.

5. The first electrode is a negative terminal electrode disposed in the outermost layer in the stacking direction of the electrode laminate, The storage module according to claim 1, wherein the second electrode is a bipolar electrode adjacent to the negative terminal electrode in the electrode laminate.

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