Power storage device

Abstract

To suppress deterioration in electrodes caused by repeated charging and discharging of a power storage device.SOLUTION: A power storage device 100 includes a first insulating part with insulation properties disposed between a laminate 10a and a collector plate 50 in a lamination direction X. The collector plate 50 has a body part 53 with electrical conductivity, and a tab part 54 with electrical conductivity projecting from an end of the body part 53 in an orthogonal direction Y orthogonal to the lamination direction X. The body part 53 has: a contact area 153 that overlaps with an exposed surface 22b in the lamination direction X and that is in contact with the exposed surface 22b; and a non-contact area 253 that overlaps with the exposed surface 22b through the first insulating part in the lamination direction X and that is not in contact with the exposed surface 22b. In the power storage device 100, charging and discharging are performed through the tab part 54, and the non-contact area 253 includes a portion of the body part 53 to which the tab part 54 is connected, as viewed from the lamination direction X.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] The power storage device described in Patent Document 1 includes a laminate having a plurality of electrodes and a pair of terminal electrodes, a sealing body, and a pair of current collecting plates. The plurality of electrodes each have a current collector provided with active material layers of different polarities on one surface and the other surface, and are laminated in the stacking direction. The pair of terminal electrodes each have a terminal current collector provided with an active material layer on one side, and are laminated so as to sandwich the plurality of electrodes in the stacking direction. The sealing body seals between adjacent current collectors in the stacking direction and between an adjacent current collector and the terminal current collector in the stacking direction. The pair of current collecting plates sandwich the laminate in the stacking direction and are electrically connected to the terminal electrodes and the plurality of electrodes by contacting the terminal current collectors.

[0003] The terminal current collector has an exposed surface that is exposed from the sealing body and is on the side opposite to the surface provided with the active material layer among the two surfaces of the terminal current collector. The current collecting plate has a conductive main body portion and a tab portion that protrudes from an end portion of the main body portion in a direction orthogonal to the stacking direction and is conductive. The main body portion contacts the exposed surface. Charging and discharging of the power storage device are performed through the tab portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the charging and discharging of the power storage device are performed through the tab portion, when current flows through the main body portion of the current collector plate during the charging and discharging of the power storage device, the current tends to concentrate on the portion of the main body portion where the tab portion is connected. The occurrence of such current concentration is not preferable because it may accelerate the deterioration of the electrodes due to being repeated each time the charging and discharging of the power storage device is performed.

Means for Solving the Problem

[0006] The power storage device for solving the above problems includes a current collector having active material layers with different polarities provided on one surface and the other surface, and a plurality of electrodes laminated in the stacking direction, and a terminal current collector having the active material layer provided on one side, and a pair of terminal electrodes laminated so as to sandwich the plurality of electrodes in the stacking direction, a laminate having, an encapsulant disposed so as to surround the periphery of the active material layer and sealing between the adjacent current collectors in the stacking direction and between the adjacent current collector and the terminal current collector in the stacking direction, a pair of current collector plates sandwiching the laminate in the stacking direction and being in conduction with the terminal electrodes and the plurality of electrodes by contacting the terminal current collector, and a first insulating portion having insulation disposed between the laminate and the current collector plate in the stacking direction, a power storage device comprising, the terminal current collector has an exposed surface exposed from the encapsulant on the surface opposite to the surface on which the active material layer is provided of both surfaces of the terminal current collector, the current collector plate has a main body portion having conductivity, and a tab portion protruding from an end portion of the main body portion in a direction orthogonal to the stacking direction and having conductivity, the main body portion has a contact region overlapping and contacting the exposed surface in the stacking direction, and a non-contact region overlapping the exposed surface through the first insulating portion in the stacking direction and not contacting the exposed surface, the power storage device performs charging and discharging through the tab portion, and the non-contact region includes a portion of the main body portion to which the tab portion is connected as viewed from the stacking direction.

[0007] According to the above configuration, the non-contact region that overlaps the exposed surface via the first insulating portion and does not contact the exposed surface in the stacking direction includes, when viewed from the stacking direction, the portion of the main body portion to which the tab portion is connected. That is, the first insulating portion is interposed between the portion of the main body portion of the current collector plate to which the tab portion is connected and the exposed surface. Thereby, the current flowing between the portion of the main body portion to which the tab portion is connected and the terminal current collector is less likely to concentrate on the portion of the main body portion to which the tab portion is connected. Thereby, it is possible to suppress the generation of a region where current concentrates on the active material layer of the terminal electrode, and thus it is possible to suppress the deterioration of the terminal electrode caused by the repeated concentration of current on the active material layer. Therefore, it is possible to suppress the deterioration of the electrode caused by the repeated charge and discharge of the power storage device.

[0008] In the power storage device, the main body portion has a frame-shaped region that overlaps the active material layer when viewed from the stacking direction, the frame-shaped region is composed of the contact region and the non-contact region, the power storage device includes a second insulating portion that contacts the exposed surface and has insulating properties, and the second insulating portion may be disposed inside the frame-shaped region when viewed from the stacking direction.

[0009] In the power storage device, the second insulating portion has an adhesive portion that is adhered to the main body portion and the exposed surface, and the adhesive portion may be surrounded by the frame-shaped region when viewed from the stacking direction.

[0010] In the power storage device, the main body portion is rectangular when viewed from the stacking direction, the frame-shaped region is rectangular frame-shaped composed of four side portions extending along the end portions of the main body portion in the orthogonal direction when viewed from the stacking direction. Among the four side portions, if two side portions extending from a common corner are defined as a first side portion and a second side portion, the contact region is located at the entire two side portions other than the first side portion and the second side portion among the four side portions, a part of the first side portion, and a part of the second side portion. The non-contact region includes a first non-contact region located at a portion of the first side portion that is not in the contact region and a second non-contact region located at a portion of the second side portion that is not in the contact region. The first non-contact region and the second non-contact region extend from the corner. Among the orthogonal directions, if the direction in which the first side portion extends is defined as a first orthogonal direction and the direction in which the second side portion extends is defined as a second orthogonal direction, the first non-contact region occupies a dimension of 20% or more and 40% or less of the dimension of the first side portion in the first orthogonal direction, and the second non-contact region may occupy a dimension of 20% or more and 40% or less of the dimension of the second side portion in the second orthogonal direction.

Advantages of the Invention

[0011] According to this invention, deterioration of the electrode caused by repeated charge and discharge of the power storage device can be suppressed.

Brief Description of the Drawings

[0012]

Figure 1

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MODE FOR CARRYING OUT THE INVENTION

[0013] [First Embodiment] Hereinafter, a first embodiment in which a power storage device is embodied will be described with reference to the drawings. <Power Storage Device> As shown in FIG. 1, the power storage device 100 includes a laminate 10a, a pair of current collector plates 50, and an insulating portion 55. The power storage device 100 in the present embodiment is a lithium-ion secondary battery. The power storage device 100 in the present embodiment includes a plurality of laminates 10a.

[0014] The power storage device 100 includes an intermediate current collector plate 19. The intermediate current collector plate 19 is an electrical conductor. The power storage device 100 in the present embodiment includes a plurality of intermediate current collector plates 19. In the present embodiment, the plurality of laminate bodies 10a and the plurality of intermediate current collector plates 19 are alternately arranged in the stacking direction X such that the laminate bodies 10a are positioned at both ends in the stacking direction X. In the laminate body 10a and the intermediate current collector plate 19 adjacent to each other in the stacking direction X, one end of the laminate body 10a in the stacking direction X and the other end of the intermediate current collector plate 19 in the stacking direction X are in contact with each other. Of the pair of current collector plates 50, one current collector plate 50 is located at one end of the power storage device 100 in the stacking direction X, and the other current collector plate 50 is located at the other end of the power storage device 100 in the stacking direction X. Thereby, the current collector plates 50 are located at both ends of the power storage device 100 in the stacking direction X. The plurality of laminate bodies 10a and the plurality of intermediate current collector plates 19 are sandwiched in the stacking direction X by the current collector plates 50 located at both ends of the power storage device 100 in the stacking direction X.

[0015] The orthogonal direction orthogonal to the stacking direction X is also simply referred to as the orthogonal direction Y hereinafter. Among the plurality of intermediate current collector plates 19, at least one intermediate current collector plate 19 may have a structure in which the cooling function by the intermediate current collector plate 19 is enhanced. In the intermediate current collector plate 19 having a structure with an enhanced cooling function, for example, at least one through hole (not shown) penetrating the intermediate current collector plate 19 in the orthogonal direction Y is formed. Since the surface area of the intermediate current collector plate 19 in which this through hole is formed is larger than the surface area of the intermediate current collector plate 19 in which no through hole is formed, heat is easily radiated from the intermediate current collector plate 19 to the outside of the power storage device 100. Therefore, the intermediate current collector plate 19 having a structure with an enhanced cooling function can promote heat radiation from the laminate body 10a in contact with this intermediate current collector plate 19.

[0016] <Laminate body> As shown in FIG. 2, the laminate body 10a has a plurality of electrodes 11, a positive electrode terminal electrode 36 and a negative electrode terminal electrode 37 as a pair of terminal electrodes.

[0017] The plurality of electrodes 11 are stacked in the stacking direction X. The plurality of electrodes 11 have a current collector 12. The current collector 12 is, for example, in the form of a sheet extending so as to be orthogonal to the stacking direction X. The current collector 12 has a first surface 12a and a second surface 12b. The first surface 12a is one surface of the current collector 12 in the stacking direction X, and the second surface 12b is the other surface of the current collector 12 in the stacking direction X.

[0018] Each of the plurality of electrodes 11 has a positive electrode active material layer 23 as an active material layer and a negative electrode active material layer 33 as an active material layer. The positive electrode active material layer 23 is provided on the first surface 12a of the current collector 12 in each of the plurality of electrodes 11. The negative electrode active material layer 33 is provided on the second surface 12b of the current collector 12 in each of the plurality of electrodes 11. That is, the current collector 12 has active material layers of different polarities provided on the first surface 12a as one surface and the second surface 12b as the other surface. The plurality of electrodes 11 are bipolar electrodes composed of the current collector 12 with the positive electrode active material layer 23 provided on the first surface 12a and the negative electrode active material layer 33 provided on the second surface 12b.

[0019] When viewed from the stacking direction X, the positive electrode active material layer 23 is formed, for example, at the central portion of the first surface 12a of the current collector 12. When viewed from the stacking direction X, the peripheral portion of the first surface 12a of the current collector 12 is a positive electrode non-coated portion 12c where the positive electrode active material layer 23 is not provided. When viewed from the stacking direction X, the positive electrode non-coated portion 12c surrounds the periphery of the positive electrode active material layer 23.

[0020] When viewed from the stacking direction X, the negative electrode active material layer 33 is formed, for example, at the central portion of the second surface 12b of the current collector 12. When viewed from the stacking direction X, the peripheral portion of the second surface 12b of the current collector 12 is a negative electrode non-coated portion 12d where the negative electrode active material layer 33 is not provided. When viewed from the stacking direction X, the negative electrode non-coated portion 12d surrounds the periphery of the negative electrode active material layer 33.

[0021] In the laminate 10a, among two electrodes 11 adjacent to each other in the stacking direction X, the first surface 12a of the current collector 12 of one electrode 11 and the second surface 12b of the current collector 12 of the other electrode 11 are stacked so as to face each other. When each electrode 11 is viewed from the stacking direction X, the positive electrode active material layer 23 and the negative electrode active material layer 33 of each electrode 11 overlap each other. When the laminate 10a is viewed from the stacking direction X, the plurality of electrodes 11 are stacked in the stacking direction X such that the positive electrode active material layer 23 and the negative electrode active material layer 33 overlap each other. The negative electrode active material layer 33 is formed, for example, to be slightly larger than the positive electrode active material layer 23. When viewed from the stacking direction X, the entire positive electrode active material layer 23 overlaps the negative electrode active material layer 33.

[0022] The current collector 12 in the present embodiment is configured by integrating a positive current collector and a negative current collector (not shown). The positive current collector and the negative current collector are, for example, in a sheet shape. The first surface 12a of the current collector 12 is constituted by one side surface of the positive current collector, and the second surface 12b is constituted by one side surface of the negative current collector. The integration of the positive current collector and the negative current collector may be performed by adhering the surface of the positive current collector on the side opposite to the first surface 12a and the surface of the negative current collector on the side opposite to the second surface 12b.

[0023] The positive current collector and the negative current collector are chemically inert electrical conductors for continuously passing an electric current through the positive electrode active material layer 23 and the negative electrode active material layer 33 during discharge or charge-discharge of the lithium-ion secondary battery. The electrical conductor is, for example, a metal material, a conductive resin material, a conductive inorganic material, or the like.

[0024] The conductive resin material is, for example, a conductive polymer material or a resin obtained by adding a conductive filler to a non-conductive polymer material as necessary. The positive current collector and the negative current collector may include a plurality of layers including one or more layers containing a metal material or a conductive resin material. The surfaces of the positive current collector and the negative current collector may be coated with a known protective layer. A metal plating may be applied to the surfaces of the positive current collector and the negative current collector by a known method such as a plating process.

[0025] The positive current collector and the negative current collector may be in the form of, for example, foil, sheet, film, wire, rod, mesh, or clad material. When the positive current collector and the negative current collector are metal foils, the positive current collector and the negative current collector may be, for example, aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil. The positive current collector and the negative current collector may be alloy foils of the above metals. The positive current collector of this embodiment is aluminum foil. The negative current collector of this embodiment is copper foil.

[0026] Note that the current collector 12 is not limited to a form in which the positive current collector and the negative current collector are integrated. For example, the current collector 12 may be a single sheet made of a metal material, a conductive resin material, a conductive inorganic material, etc., or a sheet having a plating treatment or the like applied to its surface.

[0027] The positive electrode active material layer 23 contains a positive electrode active material capable of occluding and releasing lithium ions as charge carriers. The positive electrode active material is, for example, a polyanion-based compound such as olivine-type lithium iron phosphate (LiFePO4), a lithium composite metal oxide having a layered rock salt structure, or a metal oxide having a spinel structure. The positive electrode active material is adopted from those that can be used as the positive electrode active material of a power storage device 100 such as a lithium ion secondary battery.

[0028] The negative electrode active material layer 33 contains a negative electrode active material capable of occluding and releasing charge carriers such as lithium ions. The negative electrode active material is not particularly limited as long as it is a single substance, alloy, or compound capable of occluding and releasing charge carriers such as lithium ions and can be used. For example, the negative electrode active material is, for example, Li, or carbon, a metal compound, an element alloyable with lithium, or a compound thereof. Carbon is, for example, natural graphite, artificial graphite, hard carbon (carbon with low graphitization property), or soft carbon (carbon with high graphitization property). Artificial graphite is, for example, highly oriented graphite or mesocarbon microbeads. Elements alloyable with lithium are, for example, silicon and tin.

[0029] The positive electrode active material layer 23 and the negative electrode active material layer 33 may contain components such as a conductive assistant, a binder, an electrolyte (polymer matrix, ion-conductive polymer, liquid electrolyte, etc.), and an electrolyte supporting salt (lithium salt, etc.) for enhancing ion conductivity, as required. The types and blending ratios of the above components contained in the positive electrode active material layer 23 and the negative electrode active material layer 33 are not particularly limited.

[0030] Examples of the conductive assistant include acetylene black, carbon black, and graphite. 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 poly(meth)acrylic acid, styrene-butadiene rubber, carboxymethyl cellulose, alginates such as sodium alginate and ammonium alginate, water-soluble cellulose ester crosslinked bodies, and starch-acrylic acid graft polymers. These binders can be used alone or in combination. As the solvent or dispersion medium, for example, water, N-methyl-2-pyrrolidone, etc. are used.

[0031] The laminate 10a includes a separator 35. The separator 35 is disposed between the positive electrode active material layer 23 and the negative electrode active material layer 33 in the stacking direction X. The separator 35 is a member that prevents a short circuit due to contact between the two electrodes by isolating the positive electrode active material layer 23 and the negative electrode active material layer 33, and allows charge carriers such as lithium ions to pass through.

[0032] Separator 35 is, for example, a porous sheet or non-woven fabric containing a polymer that absorbs and retains an electrolyte. The electrolyte impregnated in separator 35 is, for example, a liquid electrolyte containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent, or a polymer gel electrolyte containing an electrolyte held in a polymer matrix, etc. In the present embodiment, a liquid electrolyte is used as the electrolyte. The electrolyte salt of the liquid electrolyte is, for example, a known lithium salt such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, LiN(CF3SO2)2, etc. Also, as the non-aqueous solvent, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, ethers, etc. can be used. Note that two or more of these known solvent materials may be used in combination. The material constituting separator 35 is, for example, polypropylene, polyethylene, polyolefin, polyester, etc. Separator 35 may have a single-layer structure or a multi-layer structure. The multi-layer structure may have, for example, an adhesive layer, a ceramic layer as a heat-resistant layer, etc.

[0033] <Positive terminal electrode and negative terminal electrode> The positive terminal electrode 36 and the negative terminal electrode 37 as a pair of terminal electrodes are laminated so as to sandwich a plurality of electrodes 11 in the lamination direction X. The plurality of electrodes 11 are located between the positive terminal electrode 36 and the negative terminal electrode 37 in the lamination direction X. Each of the positive terminal electrode 36 and the negative terminal electrode 37 as terminal electrodes has a terminal current collector 22. Note that the terminal current collector 22 in the present embodiment has the same configuration as the current collector 12 in the plurality of electrodes 11. That is, the terminal current collector 22 in the present embodiment has a positive current collector and a negative current collector, similarly to the current collector 12. Note that the configuration of the terminal current collector 22 and the configuration of the current collector 12 may be different from each other. For example, at least one of the terminal current collector 22 and the current collector 12 may be constituted by a single sheet or a sheet having a plating treatment or the like on its surface.

[0034] The positive terminal electrode 36 as a terminal electrode has a positive electrode active material layer 23. The positive electrode active material layer 23 as an active material layer is provided on the covering surface 22a which is one side of the terminal current collector 22. The terminal current collector 22 in the positive terminal electrode 36 has an exposed surface 22b. The exposed surface 22b is the surface opposite to the covering surface 22a on which the positive electrode active material layer 23 as an active material layer is provided among both surfaces of the terminal current collector 22 of the positive terminal electrode 36 in the stacking direction X. A negative electrode active material layer 33 as an active material layer is not provided on the exposed surface 22b of the terminal current collector 22 in the positive terminal electrode 36. The positive terminal electrode 36 has a configuration similar to that of the electrode 11, for example, except for not having a negative electrode active material layer 33.

[0035] The negative terminal electrode 37 as a terminal electrode has a negative electrode active material layer 33. The negative electrode active material layer 33 as an active material layer is provided on the covering surface 22a which is one side of the terminal current collector 22. The terminal current collector 22 in the negative terminal electrode 37 has an exposed surface 22b. The exposed surface 22b is the surface opposite to the covering surface 22a on which the negative electrode active material layer 33 as an active material layer is provided among both surfaces of the terminal current collector 22 of the negative terminal electrode 37 in the stacking direction X. A positive electrode active material layer 23 as an active material layer is not provided on the exposed surface 22b of the terminal current collector 22 in the negative terminal electrode 37. The negative terminal electrode 37 has a configuration similar to that of the electrode 11, for example, except for not having a positive electrode active material layer 23.

[0036] At one end of the laminate 10a in the stacking direction X, the terminal current collector 22 of the positive terminal electrode 36 is located. At the other end of the laminate 10a in the stacking direction X, the terminal current collector 22 of the negative terminal electrode 37 is located. The exposed surface 22b of the terminal current collector 22 of the positive terminal electrode 36 functions as the outer surface of the terminal current collector 22 at one end in the stacking direction X. The exposed surface 22b of the terminal current collector 22 of the negative terminal electrode 37 functions as the outer surface of the laminate 10a at the other end in the stacking direction X.

[0037] <Sealing body> The power storage device 100 includes a sealing body 15. The sealing body 15 is arranged to surround the positive electrode active material layer 23 and the negative electrode active material layer 33 as the active material layers. Specifically, when viewed from the stacking direction X, the sealing body 15 surrounds the positive electrode active material layer 23 of each of the plurality of electrodes 11 and the positive electrode terminal electrode 36. When viewed from the stacking direction X, the sealing body 15 surrounds the negative electrode active material layer 33 of each of the plurality of electrodes 11 and the negative electrode terminal electrode 37. The sealing body 15 seals between adjacent current collectors 12 in the stacking direction X. The sealing body 15 seals between an adjacent current collector 12 and the terminal current collector 22 in the stacking direction X.

[0038] The sealing body 15 in the present embodiment has a plurality of seal portions 40. The plurality of seal portions 40 are made of resin. The seal portion 40 is integrated with each of the current collector 12 in the plurality of electrodes 11, the terminal current collector 22 in the positive electrode terminal electrode 36, and the terminal current collector 22 in the negative electrode terminal electrode 37.

[0039] When viewed from the stacking direction X, the seal portion 40 integrated with the current collector 12 is in a frame shape that covers the outer peripheral end of the current collector 12. The seal portion 40 integrated with the current collector 12 surrounds the positive electrode active material layer 23 and the negative electrode active material layer 33 provided on the current collector 12. Further, the seal portion 40 integrated with the current collector 12 is welded to the first surface 12a and the second surface 12b of the current collector 12. The welding method of the seal portion 40 to the current collector 12 is a known welding method such as thermal welding or ultrasonic welding in contact or non-contact. The seal portion 40 is welded to each of the positive electrode non-coated portion 12c and the negative electrode non-coated portion 12d.

[0040] When viewed from the stacking direction X, the seal portion 40 integrated with the terminal current collector 22 is in a frame shape that covers the outer peripheral end of the terminal current collector 22. The seal portion 40 integrated with the terminal current collector 22 in the positive electrode terminal electrode 36 surrounds the positive electrode active material layer 23 provided on the terminal current collector 22. The seal portion 40 integrated with the terminal current collector 22 in the negative electrode terminal electrode 37 surrounds the negative electrode active material layer 33 provided on the terminal current collector 22. Further, the seal portion 40 integrated with the terminal current collector 22 is welded to the covering surface 22a and the exposed surface 22b of the terminal current collector 22. The seal portion 40 is welded to a portion of the covering surface 22a of the terminal current collector 22 in the positive electrode terminal electrode 36 where the positive electrode active material layer 23 is not provided. The seal portion 40 is welded to a portion of the covering surface 22a of the terminal current collector 22 in the negative electrode terminal electrode 37 where the negative electrode active material layer 33 is not provided.

[0041] When viewed from the stacking direction X, the seal portion 40 is welded to the outer peripheral end of the exposed surface 22b of the terminal current collector 22 in the positive electrode terminal electrode 36. Since the seal portion 40 is not welded to the central portion of the exposed surface 22b when viewed from the stacking direction X, the central portion of the exposed surface 22b is exposed from the seal portion 40. Therefore, the exposed surface 22b is exposed from the sealing body 15.

[0042] The sealing body 15 has a plurality of spacer portions 41. The plurality of spacer portions 41 are made of resin. In the sealing body 15, the seal portion 40 and the spacer portions 41 are alternately laminated in the stacking direction X.

[0043] The spacer portion 41 is provided between the seal portion 40 provided on one current collector 12 and the seal portion 40 provided on the other current collector 12 among the adjacent current collectors 12 in the stacking direction X. In this way, the seal portion 40 and the spacer portions 41 insulate the adjacent current collectors 12 in the stacking direction X by maintaining the interval between the adjacent current collectors 12 in the stacking direction X. In this way, the seal portion 40 and the spacer portions 41 suppress the short circuit between the current collectors 12.

[0044] The spacer portion 41 is provided between the seal portion 40 provided on the current collector 12 and the seal portion 40 provided on the terminal current collector 22 among the adjacent current collectors 12 and terminal current collectors 22 in the stacking direction X. In this way, the seal portion 40 and the spacer portion 41 insulate the adjacent current collector 12 and terminal current collector 22 in the stacking direction X by maintaining the interval between the adjacent current collector 12 and terminal current collector 22 in the stacking direction X. In this way, the seal portion 40 and the spacer portion 41 suppress the short circuit between the current collector 12 and the terminal current collector 22.

[0045] When viewed from the stacking direction X, each of the plurality of spacer portions 41 has a frame shape covering the outer peripheral end of the separator 35. The spacer portion 41 may not be integrated with the separator 35, for example. When viewed from the stacking direction X, the inner peripheral end of the spacer portion 41 may be located outside the inner peripheral end of the seal portion 40 or may be located inside the inner peripheral end of the seal portion 40.

[0046] When viewed from the stacking direction X, the outer peripheral end portion of the seal portion 40 and the outer peripheral end portion of the spacer portion 41 are welded to each other outside the stacked body 10a. The welding method of the seal portion 40 and the spacer portion 41 is the same as the welding method of the seal portion 40 to the current collector 12 described above. By welding all the seal portions 40 and spacer portions 41 provided in the power storage device 100 to each other, a welded portion 42 is formed. When viewed from the stacking direction X, the welded portion 42 is located so as to surround the stacked body 10a, the seal portion 40, and the spacer portion 41. The seal portion 40, the spacer portion 41, and the welded portion 42 are integrated by the welded portion 42. The sealing body 15 is composed of the seal portion 40, the spacer portion 41, and the welded portion 42 integrated with each other. The sealing body 15 has a cylindrical shape extending in the stacking direction X.

[0047] The sealing body 15 seals the internal space S between the current collectors 12 adjacent to each other in the stacking direction X. The internal space S is defined by two current collectors 12 adjacent to each other in the stacking direction X and the sealing body 15. Further, the internal space S is defined by the current collectors 12 and the terminal current collector 22 adjacent to each other in the stacking direction X and the sealing body 15. In the internal space S, a positive electrode active material layer 23, a negative electrode active material layer 33, a separator 35, and a liquid electrolyte (not shown) are disposed. The liquid electrolyte is, for example, a so-called electrolytic solution containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent.

[0048] The sealing body 15 can suppress the intrusion of moisture from the outside of the power storage device 100 into the internal space S. The sealing body 15 can suppress the leakage of the liquid electrolyte stored in the internal space S to the outside of the power storage device 100.

[0049] <Current collector plate> The power storage device 100 includes a positive electrode current collector plate 51 and a negative electrode current collector plate 52 as a pair of current collector plates 50. The positive electrode current collector plate 51 is located on one side of the stacked body 10a in the stacking direction X. The negative electrode current collector plate 52 is located on the other side of the stacked body 10a in the stacking direction X. Thus, the current collector plates 50 sandwich the stacked body 10a in the stacking direction X.

[0050] Note that the positive electrode current collector plate 51 and the negative electrode current collector plate 52 in the present embodiment have a common configuration with each other, but the positive electrode current collector plate 51 and the negative electrode current collector plate 52 may have different configurations from each other. The description of the current collector plate 50 below is a description of the common configuration of the positive electrode current collector plate 51 and the negative electrode current collector plate 52 unless otherwise specified.

[0051] The current collector plate 50 has a main body portion 53 and a tab portion 54. The insulating portion 55 is arranged to contact either the positive terminal electrode 36 or the negative terminal electrode 37. Also, the insulating portion 55 is arranged to contact the current collector plate 50. The main body portion 53 of the current collector plate 50 is an electrical conductor. That is, the main body portion 53 has conductivity. The material adopted for the main body portion 53 is, for example, a metallic material such as aluminum, copper, stainless steel, etc. The material adopted for the insulating portion 55 is an insulating material. The insulating material is, for example, glass, rubber, and plastic. Therefore, the insulating portion 55 in the present embodiment has insulating properties.

[0052] As shown in FIGS. 3 and 4, the main body portion 53 is rectangular when viewed from the stacking direction X. The main body portion 53 only needs to be electrically connected to the terminal current collector 22, and the main body portion 53 only needs to overlap the positive electrode active material layer 23 when viewed from the stacking direction X. The main body portion 53 in the present embodiment is rectangular when viewed from the stacking direction X.

[0053] The main body portion 53 has a plate-shaped main body portion 53c and a protruding main body portion 53d. The plate-shaped main body portion 53c is in the shape of a rectangular flat plate. The plate-shaped main body portion 53c in the present embodiment is rectangular when viewed from the stacking direction X. Of the two directions orthogonal to each other in the orthogonal direction Y, one direction is defined as the first orthogonal direction Y1, and the other direction is defined as the second orthogonal direction Y2. When viewed from the stacking direction X, both ends of the plate-shaped main body portion 53c in the second orthogonal direction Y2 are referred to as the first ends 53a, and both ends of the plate-shaped main body portion 53c in the first orthogonal direction Y1 are referred to as the second ends 53b. The first end 53a extends in the first orthogonal direction Y1. The second end 53b extends in the second orthogonal direction Y2. In the present embodiment, the dimension of the first end 53a in the first orthogonal direction Y1 is larger than the dimension of the second end 53b in the second orthogonal direction Y2. Also, the first end 53a corresponds to the end of the main body portion 53 in the second orthogonal direction Y2. The second end 53b corresponds to the end of the main body portion 53 in the first orthogonal direction Y1.

[0054] The power storage device 100 is charged and discharged through the tab portion 54. The tab portion 54 protrudes from the second end portion 53b which is the end portion of the main body portion 53 in the first orthogonal direction Y1. The tab portion 54 is made of the same material as the main body portion 53. Therefore, the tab portion 54 has conductivity. The tab portion 54 is in a flat plate shape extending so as to be orthogonal to the stacking direction X. The dimension of the tab portion 54 in the stacking direction X may be, for example, a size different from the dimension of the plate-shaped main body portion 53c in the stacking direction X, or may be the same size as the dimension of the plate-shaped main body portion 53c in the stacking direction X. Both end faces of the tab portion 54 in the stacking direction X may be flush with both end faces of the plate-shaped main body portion 53c in the stacking direction X, for example.

[0055] In the present embodiment, the tab portion 54 protrudes from a portion of the second end portion 53b that is offset toward one end side in the second orthogonal direction Y2 from the center of the second end portion 53b in the second orthogonal direction Y2. The portion of the plate-shaped main body portion 53c to which the tab portion 54 is connected is also referred to as a connection portion 53e. The connection portion 53e corresponds to the portion of the main body portion 53 to which the tab portion 54 is connected.

[0056] The protruding main body portion 53d protrudes from the plate-shaped main body portion 53c in the stacking direction X. When viewed from the stacking direction X, the protruding main body portion 53d is located along the outer peripheral edge of the plate-shaped main body portion 53c. Specifically, the protruding main body portion 53d is located along the whole of one of the two first end portions 53a and a part of the other first end portion 53a, and along the whole of one of the two second end portions 53b and a part of the other second end portion 53b. When viewed from the stacking direction X, the protruding main body portion 53d has a shape in which a part including one corner is removed from a rectangular frame-shaped member. When viewed from the stacking direction X, the protruding main body portion 53d is provided at a portion of the outer peripheral edge of the plate-shaped main body portion 53c excluding the connection portion 53e.

[0057] As shown in FIGS. 2 and 3, the main body portion 53 overlaps the exposed surface 22b in the stacking direction X. Specifically, the main body portion 53 of the positive current collector plate 51 overlaps the exposed surface 22b of the end current collector 22 of the positive terminal electrode 36 in the stacking direction X. The main body portion 53 of the negative current collector plate 52 overlaps the exposed surface 22b of the end current collector 22 of the negative terminal electrode 37 in the stacking direction X.

[0058] <Contact region and non-contact region> The main body portion 53 has a contact region 153 and a non-contact region 253. In the present embodiment, a first region located along the inner peripheral end of the protruding main body portion 53d as viewed from the stacking direction X and a second region of the plate-shaped main body portion 53 that overlaps the first region in the stacking direction X correspond to the contact region 153. A portion of the plate-shaped main body portion 53 that does not overlap the protruding main body portion 53d in the stacking direction X corresponds to the non-contact region 253.

[0059] As shown in FIG. 5, the connection portion 53e to which the tab portion 54 is connected in the plate-shaped main body portion 53 functions as the non-contact region 253. Therefore, the non-contact region 253 includes the connection portion 53e, which is the portion of the main body portion 53 to which the tab portion 54 is connected, as viewed from the stacking direction X.

[0060] As shown in FIGS. 2 and 3, the insulating portion 55 covers one end surface of the non-contact region 253 in the main body portion 53 in the stacking direction X. Therefore, the insulating portion 55 covers one end surface of the connection portion 53e in the stacking direction X. As viewed from the stacking direction X, the outer shape of the insulating portion 55 is a shape in which a notch having the same shape as the protruding main body portion 53d is formed in a plate-shaped member having the same shape as the plate-shaped main body portion 53c. In short, as viewed from the stacking direction X, the outer shape of the insulating portion 55 is a shape that can cover the entire end surface of the plate-shaped main body portion 53c in the stacking direction X with the insulating portion 55 and the protruding main body portion 53d.

[0061] In this embodiment, the insulating portion 55 is composed of a first insulating portion 55c and a second insulating portion 55d. Therefore, the power storage device 100 includes the first insulating portion 55c and the second insulating portion 55d. The first insulating portion 55c and the second insulating portion 55d have insulating properties. In this embodiment, the first insulating portion 55c and the second insulating portion 55d are made of the same material, but the materials of the first insulating portion 55c and the second insulating portion 55d may be different from each other.

[0062] The second insulating portion 55d is a rectangular portion of the insulating portion 55 that is surrounded by the protruding main body portion 53d as viewed from the stacking direction X. The first insulating portion 55c is the portion of the insulating portion 55 other than the second insulating portion 55d. The first insulating portion 55c is disposed between the laminate 10a and the current collector plate 50 in the stacking direction X. Specifically, the first insulating portion 55c is disposed between the positive terminal electrode 36 and the positive current collector plate 51 in the stacking direction X. The first insulating portion 55c is disposed between the negative terminal electrode 37 and the negative current collector plate 52 in the stacking direction X.

[0063] The second insulating portion 55d contacts the exposed surface 22b. Specifically, the second insulating portion 55d contacts the exposed surface 22b of the terminal current collector 22 of the positive terminal electrode 36 in the stacking direction X. The second insulating portion 55d contacts the exposed surface 22b of the terminal current collector 22 of the negative terminal electrode 37 in the stacking direction X.

[0064] The dimension of the insulating portion 55 in the stacking direction X may be, for example, the same as the dimension of the protruding main body portion 53d in the stacking direction X. In this case, the end face of the protruding main body portion 53d in the stacking direction X and the end face of the insulating portion 55 in the stacking direction X are flush.

[0065] As shown in FIG. 3, the contact region 153 is a part of the frame-shaped region 80 as viewed from the stacking direction X. The frame-shaped region 80 is a frame-shaped region that extends along the first end portion 53a and the second end portion 53b, which are the end portions of the main body portion 53 in the orthogonal direction Y, of the main body portion 53 as viewed from the stacking direction X. In other words, the main body portion 53 has a frame-shaped frame-shaped region 80.

[0066] The frame-shaped region 80 overlaps with the positive electrode active material layer 23 and the negative electrode active material layer 33 as the active material layers when viewed from the stacking direction X. For example, the frame-shaped region 80 in the positive electrode current collector 51 overlaps with the positive electrode active material layer 23 of the positive electrode terminal electrode 36 when viewed from the stacking direction X. For example, the frame-shaped region 80 in the negative electrode current collector 52 overlaps with the negative electrode active material layer 33 of the negative electrode terminal electrode 37 when viewed from the stacking direction X. Since the second insulating portion 55d covers one end surface of the non-contact region 253 in the stacking direction X, it is arranged inside the frame-shaped region 80 when viewed from the stacking direction X.

[0067] The frame-shaped region 80 is in a rectangular frame shape composed of four side portions 80a extending along the first end portion 53a and the second end portion 53b as the end portions of the main body portion 53 in the orthogonal direction Y when viewed from the stacking direction X. Of the four side portions 80a, two side portions 80a extending from a common corner portion 80b are defined as the first side portion 81 and the second side portion 82.

[0068] The first side portion 81 in the present embodiment is a region that extends along the first end portion 53a of the frame-shaped region 80. Therefore, the first side portion 81 extends in the first orthogonal direction Y1. In other words, among the orthogonal directions Y, the direction in which the first side portion 81 extends is defined as the first orthogonal direction Y1. The second side portion 82 in the present embodiment is a region that extends along the second end portion 53b of the frame-shaped region 80. Therefore, the second side portion 82 extends in the second orthogonal direction Y2. In other words, among the orthogonal directions Y, the direction in which the second side portion 82 extends is defined as the second orthogonal direction Y2.

[0069] The contact region 153 is located at the entirety of two side portions 80a other than the first side portion 81 and the second side portion 82 among the four side portions 80a, a part of the first side portion 81, and a part of the second side portion 82.

[0070] The non-contact region 253 corresponds to a region 83 of the main body portion 53 that, when viewed in the stacking direction X, is a portion other than the contact region 153 of the frame-shaped region 80. That is, the frame-shaped region 80 consists of the contact region 153 and the non-contact region 253. Specifically, the non-contact region 253 includes a first non-contact region 83a located in a portion of the first side portion 81 that is not the contact region 153, and a second non-contact region 83b located in a portion of the second side portion 82 that is not the contact region 153. The first non-contact region 83a and the second non-contact region 83b extend from the corner portion 80b.

[0071] As shown in FIG. 2, the contact region 153 overlaps and contacts the exposed surface 22b in the stacking direction X. Specifically, the contact region 153 of the positive electrode current collector plate 51 overlaps and contacts the exposed surface 22b of the terminal current collector 22 of the positive electrode terminal electrode 36 in the stacking direction X. The contact region 153 of the negative electrode current collector plate 52 overlaps and contacts the exposed surface 22b of the terminal current collector 22 of the negative electrode terminal electrode 37 in the stacking direction X. Therefore, the current collector plate 50 is in conduction with the positive electrode terminal electrode 36 as a terminal electrode, the negative electrode terminal electrode 37 as a terminal electrode, and the plurality of electrodes 11 by contacting the terminal current collector 22.

[0072] The non-contact region 253 overlaps the exposed surface 22b via the first insulating portion 55c in the stacking direction X and does not contact the exposed surface 22b. Specifically, the non-contact region 253 of the positive electrode current collector plate 51 overlaps the exposed surface 22b of the terminal current collector 22 of the positive electrode terminal electrode 36 via the first insulating portion 55c in the stacking direction X and does not contact this exposed surface 22b. The non-contact region 253 of the negative electrode current collector plate 52 overlaps the exposed surface 22b of the terminal current collector 22 of the negative electrode terminal electrode 37 via the first insulating portion 55c in the stacking direction X and does not contact this exposed surface 22b.

[0073] <Dimensions of the First Non-Contact Region and the Second Non-Contact Region> As shown in FIG. 3, the dimension of the first side portion 81 in the first orthogonal direction Y1 is defined as a first dimension L1. The first non-contact region 83a occupies a dimension of 20% or more and 40% or less of the first dimension L1. That is, when the dimension of the first non-contact region 83a in the first orthogonal direction Y1 is defined as a first non-contact region dimension La, the first non-contact region dimension La is 20% or more and 40% or less of the first dimension L1.

[0074] The dimension of the second side portion 82 in the second orthogonal direction Y2 is defined as a second dimension L2. The second non-contact region 83b occupies a dimension of 20% or more and 40% or less of the second dimension L2. That is, when the dimension of the second non-contact region 83b in the second orthogonal direction Y2 is defined as a second non-contact region dimension Lb, the second non-contact region dimension Lb is 20% or more and 40% or less of the second dimension L2.

[0075] <Relationship between the ratio of the non-contact region and the variation in current in the terminal electrode> The relationship between the ratio of the first non-contact region 83a and the second non-contact region 83b as the non-contact region 253 and the variation in current in the terminal electrode was measured experimentally. The ratio of the first non-contact region 83a is the ratio of the dimension occupied by the first non-contact region 83a in the first dimension L1 of the first side portion 81. The ratio of the second non-contact region 83b is the ratio of the dimension occupied by the second non-contact region 83b in the second dimension L2 of the second side portion 82. In the experiment, a current collector plate 50 was adopted in which the ratio of the dimension occupied by the first non-contact region 83a in the first dimension L1 and the ratio of the dimension occupied by the second non-contact region 83b in the second dimension L2 are the same. The ratio of the dimension occupied by the first non-contact region 83a in the first dimension L1 and the ratio of the dimension occupied by the second non-contact region 83b in the second dimension L2 are hereinafter referred to as the ratio of the non-contact region 253.

[0076] Either the positive terminal electrode 36 or the negative terminal electrode 37 that is electrically connected to the current collector plate 50 is adopted as the terminal electrode. In this case, the variation in current in the terminal electrode is a value such that the difference between the largest current value and the smallest current value among the currents measured at a plurality of locations on the terminal electrode is larger, the greater the variation in the current.

[0077] In the experiment, for five current collectors 50 with different ratios of the non-contact region 253, the variation in current in the terminal electrodes adjacent in the stacking direction X was measured. The ratio of the non-contact region 253 in each of the five current collectors 50 is 0 (zero)%, Lx%, Ly%, Lz%, and 50%. Lx%, Ly%, and Lz% are all 20% or more and 40% or less. Ly% is a larger ratio than Lx%. Lz% is a larger ratio than Lx% and Ly%.

[0078] As shown in FIG. 6, the terminal electrode adjacent in the stacking direction X to the current collector 50 with a non-contact region 253 ratio of 0 (zero)% and the terminal electrode adjacent in the stacking direction X to the current collector 50 with a non-contact region 253 ratio of 50% showed relatively large variations in current. In contrast, the terminal electrodes adjacent in the stacking direction X to the current collector 50 with a non-contact region 253 ratio of Lx%, the current collector 50 with a non-contact region 253 ratio of Ly%, and the current collector 50 with a non-contact region 253 ratio of Lz% showed relatively small variations in current. Therefore, it was shown that an effect of suppressing variations within the terminal electrodes can be obtained in the terminal electrodes adjacent in the stacking direction X to the current collector 50 with a non-contact region 253 ratio of 20% or more and 40% or less.

[0079] [Actions and Effects of the First Embodiment] According to the first embodiment, the following actions and effects can be obtained. (1-1) In the stacking direction X, the non-contact region 253 that overlaps the exposed surface 22b via the first insulating portion 55c and does not contact the exposed surface 22b includes the connection portion 53e, which is the portion of the main body portion 53 to which the tab portion 54 is connected, when viewed from the stacking direction X. That is, the first insulating portion 55c is interposed between the portion of the main body portion 53 of the current collector plate 50 to which the tab portion 54 is connected and the exposed surface 22b. As a result, the current flowing between the connection portion 53e, which is the portion of the main body portion 53 to which the tab portion 54 is connected, and the terminal current collector 22 is less likely to concentrate on the portion of the main body portion 53 to which the tab portion 54 is connected. Thereby, in the active material layer of the terminal electrode, the current is less likely to concentrate in the region overlapping the portion of the main body portion 53 to which the tab portion 54 is connected in the stacking direction X. It is possible to suppress the occurrence of a region where current concentrates in the positive electrode active material layer 23 as the active material layer of the positive electrode terminal electrode 36 as the terminal electrode and the negative electrode active material layer 33 as the active material layer of the negative electrode terminal electrode 37 as the terminal electrode. Therefore, it is possible to suppress the deterioration of the positive electrode terminal electrode 36 and the negative electrode terminal electrode 37 as the terminal electrodes, which is caused by the repeated concentration of current on the positive electrode active material layer 23 as the active material layer of the positive electrode terminal electrode 36 and the negative electrode active material layer 33 as the active material layer of the negative electrode terminal electrode 37. Therefore, it is possible to suppress the deterioration of the positive electrode terminal electrode 36 and the negative electrode terminal electrode 37 as the electrodes, which is caused by the repeated charge and discharge of the power storage device 100.

[0080] (1-2) The main body portion 53 has a frame-shaped region 80 that overlaps with the active material layer when viewed from the stacking direction X. The frame-shaped region 80 consists of a contact region 153 and a non-contact region 253. The power storage device 100 includes a second insulating portion 55d that is in contact with the exposed surface 22b and has insulating properties. The second insulating portion 55d is disposed inside the frame-shaped region 80 when viewed from the stacking direction X. Therefore, when the power storage device 100 is charged and discharged, current flows through a part of the frame-shaped region 80 that extends along the first end portion 53a and the second end portion 53b of the main body portion 53. Therefore, the current path between the connection portion 53e, which is the portion of the main body portion 53 to which the tab portion 54 is connected, and the terminal current collector 22 can be separated from the connection portion 53e, which is the portion of the main body portion 53 to which the tab portion 54 is connected. Thereby, the concentration of current on the positive electrode active material layer 23 as the active material layer of the positive electrode terminal electrode 36 and the negative electrode active material layer 33 as the active material layer of the negative electrode terminal electrode 37 can be further suppressed. Therefore, the deterioration of the positive electrode terminal electrode 36 and the negative electrode terminal electrode 37 as electrodes caused by the repeated charging and discharging of the power storage device 100 can be further suppressed.

[0081] (1-3) The first non-contact region 83a occupies a dimension that is 20% or more and 40% or less of the dimension of the first side portion 81 in the first orthogonal direction Y1. The second non-contact region 83b occupies a dimension that is 20% or more and 40% or less of the dimension of the second side portion 82 in the second orthogonal direction Y2. Therefore, the variation in current in the positive electrode terminal electrode 36 and the negative electrode terminal electrode 37 as the terminal electrodes can be reduced, and thus the deterioration of the positive electrode terminal electrode 36 and the negative electrode terminal electrode 37 as electrodes caused by the large variation in current can be suppressed.

[0082] [Second Embodiment] Hereinafter, a second embodiment in which the power storage device is embodied will be described with reference to the drawings. The power storage device in the second embodiment is different from the power storage device in the first embodiment in the configuration of the pair of current collectors 50. In the following description, the description will focus on the configuration different from that of the first embodiment. The description of the same configuration as that of the first embodiment will be omitted as appropriate.

[0083] [Current Collector] As shown in FIG. 7, the power storage device 100 includes a positive electrode current collector plate 51 and a negative electrode current collector plate 52 as a pair of current collector plates 50, and an insulating portion 55. Note that the positive electrode current collector plate 51 and the negative electrode current collector plate 52 in the present embodiment have a common configuration with each other, but the positive electrode current collector plate 51 and the negative electrode current collector plate 52 may have different configurations from each other. In the following description of the current collector plate 50, unless otherwise specified, the description will be of the configuration common to the positive electrode current collector plate 51 and the negative electrode current collector plate 52.

[0084] The current collector plate 50 has a main body portion 53 having conductivity and a tab portion 54 having conductivity. The insulating portion 55 is disposed so as to contact the current collector plate 50. Further, the insulating portion 55 is disposed so as to contact either the positive electrode terminal electrode 36 or the negative electrode terminal electrode 37.

[0085] As shown in FIGS. 8 and 9, the main body portion 53 is frame-shaped when viewed from the stacking direction X. The main body portion 53 in the present embodiment is in a rectangular frame shape forming a rectangle when viewed from the stacking direction X. When viewed from the stacking direction X, both ends of the main body portion 53 in the second orthogonal direction Y2 are referred to as first end portions 53a, and both ends of the main body portion 53 in the first orthogonal direction Y1 are referred to as second end portions 53b. The first end portion 53a extends in the first orthogonal direction Y1. The second end portion 53b extends in the second orthogonal direction Y2. In the present embodiment, the dimension of the first end portion 53a in the first orthogonal direction Y1 is larger than the dimension of the second end portion 53b in the second orthogonal direction Y2. Further, the first end portion 53a corresponds to the end portion of the main body portion 53 in the second orthogonal direction Y2. The second end portion 53b corresponds to the end portion of the main body portion 53 in the first orthogonal direction Y1.

[0086] The tab portion 54 protrudes from the second end portion 53b which is an end portion of the main body portion 53 in the first orthogonal direction Y1. The dimension of the tab portion 54 in the stacking direction X may be, for example, a size different from the dimension of the main body portion 53 in the stacking direction X, or may be the same size as the dimension of the main body portion 53 in the stacking direction X. The connection portion 53e is a portion of the main body portion 53 to which the tab portion 54 is connected.

[0087] The main body part 53 in this embodiment has a first main body part 61 and a second main body part 62. The main body part 53 in this embodiment is formed in a frame shape by the first main body part 61 and the second main body part 62 when viewed from the stacking direction X.

[0088] The first main body part 61 is located along the whole of one of the two first end parts 53a and a part of the other first end part 53a, and along the whole of one of the two second end parts 53b and a part of the other second end part 53b. When viewed from the stacking direction X, the first main body part 61 has a shape in which a part including one corner is removed from a rectangular frame-shaped member. When viewed from the stacking direction X, the first main body part 61 is provided in the part of the main body part 53 excluding the connection part 53e.

[0089] The second main body part 62 corresponds to the part of the main body part 53 other than the first main body part 61. That is, the second main body part 62 is located along the part of one of the first end parts 53a other than the first main body part 61 and the part of one of the second end parts 53b other than the first main body part 61. When viewed from the stacking direction X, the second main body part 62 has a shape that can form a rectangular frame-shaped main body part 53 with the first main body part 61. When viewed from the stacking direction X, the second main body part 62 is provided in the part of the main body part 53 including the connection part 53e.

[0090] The dimension of the second main body part 62 in the stacking direction X is smaller than the dimension of the first main body part 61 in the stacking direction X. At the end part of both ends of the main body part 53 in the stacking direction X that faces the exposed surface 22b, a step is formed at the boundary between the first main body part 61 and the second main body part 62. At the end part of both ends of the main body part 53 in the stacking direction X that faces the exposed surface 22b, the second main body part 62 has a shape that is recessed more than the first main body part 61.

[0091] As shown in FIGS. 7 and 8, the main body portion 53 overlaps the exposed surface 22b in the stacking direction X. Specifically, the main body portion 53 of the positive current collector plate 51 overlaps the exposed surface 22b of the terminal current collector 22 of the positive terminal electrode 36 in the stacking direction X. The main body portion 53 of the negative current collector plate 52 overlaps the exposed surface 22b of the terminal current collector 22 of the negative terminal electrode 37 in the stacking direction X.

[0092] <Contact region and non-contact region> The main body portion 53 has a contact region 153 and a non-contact region 253. In the present embodiment, the region located along the inner peripheral end of the first main body portion 61 as viewed from the stacking direction X corresponds to the contact region 153. The region located along the inner peripheral end of the second main body portion 62 as viewed from the stacking direction X corresponds to the non-contact region 253.

[0093] As shown in FIGS. 8 and 10, the connection portion 53e to which the tab portion 54 is connected in the main body portion 53 functions as the non-contact region 253. Therefore, the non-contact region 253 includes the connection portion 53e which is the portion of the main body portion 53 to which the tab portion 54 is connected as viewed from the stacking direction X.

[0094] The insulating portion 55 is composed of an insulating member 55a and an adhesive portion 55b. In other words, the second insulating portion 55d has the adhesive portion 55b. The insulating member 55a in the present embodiment functions as the first insulating portion 55c. The adhesive portion 55b in the present embodiment functions as the second insulating portion 55d. Therefore, the power storage device 100 includes the first insulating portion 55c and the second insulating portion 55d. The material employed for the insulating member 55a is the same insulating material as the first insulating portion 55c in the first embodiment. The material employed for the adhesive portion 55b is an insulating material having an adhesive function. Therefore, the first insulating portion 55c and the second insulating portion 55d in the present embodiment have insulating properties. The first insulating portion 55c and the second insulating portion 55d in the present embodiment are made of different materials from each other, but the first insulating portion 55c and the second insulating portion 55d may be made of the same material as each other.

[0095] The connecting portion 55b is located in an internal region 53h which is an internal region inside the main body portion 53. The connecting portion 55b is adhered to the inner peripheral surface of the main body portion 53. The connecting portion 55b is adhered to a portion of the exposed surface 22b that overlaps the connecting portion 55b when viewed from the lamination direction X. Therefore, the connecting portion 55b is adhered to both the main body portion 53 and the exposed surface 22b. The connecting portion 55b as the second insulating portion 55d contacts the exposed surface 22b.

[0096] The insulating member 55a covers one end surface in the lamination direction X of the non-contact region 253 in the main body portion 53. Therefore, the insulating portion 55 covers one end surface of the connecting portion 53e in the lamination direction X. When viewed from the lamination direction X, the outer shape of the insulating member 55a is the same as that of the second main body portion 62. In short, when viewed from the lamination direction X, the outer shape of the insulating member 55a is a shape that can cover the entire end surface of the second main body portion 62 in the lamination direction X by the insulating member 55a. Note that the insulating member 55a covers the end portion of the second main body portion 62 that constitutes the end portion facing the exposed surface 22b among both end portions of the main body portion 53 in the lamination direction X.

[0097] The dimension of the insulating member 55a in the lamination direction X may be, for example, the same as the difference between the dimension of the second main body portion 62 and the dimension of the first main body portion 61 in the lamination direction X. In this case, the end surface of the first main body portion 61 in the lamination direction X and the end surface of the insulating member 55a in the lamination direction X are flush.

[0098] As shown in FIG. 8, similar to the first embodiment, the contact region 153 in this embodiment is a part of the frame-shaped region 80 when viewed from the lamination direction X. The internal region 53h is surrounded by the frame-shaped region 80 when viewed from the lamination direction X. Therefore, the connecting portion 55b is surrounded by the frame-shaped region 80 when viewed from the lamination direction X. The connecting portion 55b as the second insulating portion 55d is disposed inside the frame-shaped region 80 when viewed from the lamination direction X.

[0099] Similar to the first embodiment, the contact region 153 is located on the entire two side portions 80a out of the four side portions 80a, excluding the first side portion 81 and the second side portion 82, a part of the first side portion 81, and a part of the second side portion 82. The non-contact region 253 in the present embodiment is a region 83 which is a portion of the main body portion 53 other than the contact region 153 of the frame-shaped region 80 when viewed from the stacking direction X. The non-contact region 253 in the present embodiment consists of a first non-contact region 83a located in a portion of the first side portion 81 that is not the contact region 153 and a second non-contact region 83b located in a portion of the second side portion 82 that is not the contact region 153. The first non-contact region 83a and the second non-contact region 83b extend from the corner portion 80b.

[0100] As shown in FIG. 7, similar to the first embodiment, the contact region 153 overlaps the exposed surface 22b in the stacking direction X and contacts the exposed surface 22b in the stacking direction X. The current collector plate 50 is in conduction with the positive electrode terminal electrode 36 as the terminal electrode, the negative electrode terminal electrode 37 as the terminal electrode, and the plurality of electrodes 11 by contacting the terminal current collector 22.

[0101] As shown in FIG. 10, the non-contact region 253 overlaps the exposed surface 22b through the insulating member 55a as the first insulating portion 55c in the stacking direction X and does not contact the exposed surface 22b. The first insulating portion 55c is disposed between the laminate 10a and the current collector plate 50 in the stacking direction X. Specifically, the first insulating portion 55c is disposed between the positive electrode terminal electrode 36 and the positive electrode current collector plate 51 in the stacking direction X. The first insulating portion 55c is disposed between the negative electrode terminal electrode 37 and the negative electrode current collector plate 52 in the stacking direction X.

[0102] The second insulating portion 55d contacts the exposed surface 22b. Specifically, the second insulating portion 55d contacts the exposed surface 22b of the terminal current collector 22 of the positive electrode terminal electrode 36 in the stacking direction X. The second insulating portion 55d contacts the exposed surface 22b of the terminal current collector 22 of the negative electrode terminal electrode 37 in the stacking direction X.

[0103] As shown in FIG. 8, let the dimension of the first side portion 81 in the first orthogonal direction Y1 be the first dimension L1. Similar to the first embodiment, the first non-contact region 83a occupies a dimension of 20% or more and 40% or less of the first dimension L1.

[0104] Let the dimension of the second side portion 82 in the second orthogonal direction Y2 be the second dimension L2. Similar to the first embodiment, the second non-contact region 83b occupies a dimension of 20% or more and 40% or less of the second dimension L2.

[0105] [Actions and Effects of the Second Embodiment] According to the second embodiment, in addition to the same actions and effects as the first embodiment, the following effects can be obtained.

[0106] (2-1) The second insulating portion 55d has an adhesive portion 55b that is adhered to the main body portion 53 and the exposed surface 22b. The adhesive portion 55b is surrounded by the frame-shaped region 80 when viewed from the lamination direction X. Therefore, a part of the insulating portion 55 can function as the adhesive portion 55b that is adhered to the main body portion 53 and the exposed surface 22b. Thus, while insulating the non-contact region 253 in the main body portion 53 from the terminal current collector 22, the laminate 10a can be fixed by the adhesive portion 55b.

[0107] [Third Embodiment] Hereinafter, a third embodiment in which the power storage device is embodied will be described with reference to the drawings. The power storage device in the third embodiment is different from the power storage device in the first embodiment in the configuration of a pair of current collector plates 50. In the following description, the description will focus on the configuration different from the first embodiment. The description of the same configuration as the first embodiment will be omitted as appropriate.

[0108] [Current Collector Plate] As shown in FIG. 11, the power storage device 100 includes a positive current collector plate 51 as the current collector plate 50 and a negative current collector plate 52 as the current collector plate 50. Note that the positive current collector plate 51 and the negative current collector plate 52 in the present embodiment have a common configuration with each other, but the positive current collector plate 51 and the negative current collector plate 52 may have different configurations from each other. In the following description of the current collector plate 50, unless otherwise specified, it is a description of the common configuration of the positive current collector plate 51 and the negative current collector plate 52.

[0109] As shown in FIG. 12, the current collector plate 50 has a conductive main body portion 53 and a conductive tab portion 54. An insulating portion 55 having insulating properties is disposed so as to contact the current collector plate 50. Further, the insulating portion 55 is disposed so as to contact either the positive terminal electrode 36 or the negative terminal electrode 37. The material employed for the main body portion 53 and the material employed for the insulating portion 55 are the same as those in the first embodiment, respectively.

[0110] As shown in FIGS. 4 and 12, the main body portion 53 is rectangular when viewed from the stacking direction X. The main body portion 53 in the present embodiment is rectangular when viewed from the stacking direction X. The main body portion 53 has a plate-like main body portion 53c and a protruding main body portion 53d. The plate-like main body portion 53c in the present embodiment has the same shape as the plate-like main body portion 53c in the first embodiment. The configuration of the tab portion 54 is the same as that of the tab portion 54 in the first embodiment. The portion of the plate-like main body portion 53c to which the tab portion 54 is connected is also referred to as a connection portion 53e. The connection portion 53e corresponds to the portion of the main body portion 53 to which the tab portion 54 is connected.

[0111] The protruding main body portion 53d protrudes from the plate-like main body portion 53c in the stacking direction X. When viewed from the stacking direction X, the protruding main body portion 53d covers a portion of the end portion of the plate-like main body portion 53c in the stacking direction X excluding a part including the connection portion 53e. When viewed from the stacking direction X, the protruding main body portion 53d has a shape in which a part including one corner is removed from a rectangular member having the same shape as the plate-like main body portion 53c.

[0112] As shown in FIGS. 11 and 12, similar to the first embodiment, the main body portion 53 overlaps the exposed surface 22b in the stacking direction X. The main body portion 53 has a contact region 153 and a non-contact region 253. In the present embodiment, one end surface of the protruding main body portion 53d in the stacking direction X corresponds to the contact region 153. A portion of the plate-shaped main body portion 53c that does not overlap the protruding main body portion 53d in the stacking direction X corresponds to the non-contact region 253.

[0113] As shown in FIG. 13, a connection portion 53e to which the tab portion 54 is connected in the plate-shaped main body portion 53c functions as the non-contact region 253. Therefore, the non-contact region 253 includes the connection portion 53e which is a portion of the main body portion 53 to which the tab portion 54 is connected as viewed in the stacking direction X.

[0114] As shown in FIGS. 12 and 13, the insulating portion 55 covers one end surface in the stacking direction X of the non-contact region 253 in the main body portion 53. Therefore, the insulating portion 55 covers one end surface of the connection portion 53e in the stacking direction X. As viewed in the stacking direction X, the outer shape of the insulating portion 55 is the same as the portion of the plate-shaped main body portion 53c that does not overlap the protruding main body portion 53d. In short, as viewed in the stacking direction X, the outer shape of the insulating portion 55 is a shape that can cover the entire end surface of the plate-shaped main body portion 53c in the stacking direction X with the insulating portion 55 and the protruding main body portion 53d.

[0115] The insulating portion 55 in the present embodiment functions as a first insulating portion 55c. Therefore, the power storage device 100 includes the first insulating portion 55c. The first insulating portion 55c has insulating properties. The first insulating portion 55c is disposed between the laminate 10a and the current collector plate 50 in the stacking direction X. Specifically, the first insulating portion 55c is disposed between the positive terminal electrode 36 and the positive current collector plate 51 in the stacking direction X. The first insulating portion 55c is disposed between the negative terminal electrode 37 and the negative current collector plate 52 in the stacking direction X.

[0116] Similar to the first embodiment, the dimension of the insulating portion 55 in the stacking direction X may be, for example, the same as the dimension of the protruding main body portion 53d in the stacking direction X. In this case, the end face of the protruding main body portion 53d in the stacking direction X and the end face of the insulating portion 55 in the stacking direction X are flush.

[0117] As shown in FIG. 11, similar to the first embodiment, the contact region 153 overlaps and contacts the exposed surface 22b in the stacking direction X. Therefore, the current collector plate 50 is in conduction with the positive terminal electrode 36 as the terminal electrode, the negative terminal electrode 37 as the terminal electrode, and the plurality of electrodes 11 by contacting the terminal current collector 22.

[0118] As shown in FIG. 13, similar to the first embodiment, the non-contact region 253 overlaps the exposed surface 22b via the first insulating portion 55c in the stacking direction X and does not contact the exposed surface 22b. [Operations and Effects of the Third Embodiment] According to the third embodiment, the same operations as those of the first embodiment and the same effects as the effects of (1-1) in the first embodiment can be obtained.

[0119] [Modification Examples] Note that the embodiment can be implemented with the following modifications. The embodiment and the following modification examples can be implemented in combination with each other within a technically non-conflicting range.

[0120] ○ The tab portion 54 may protrude from the center of the second end portion 53b in the second end portion 53b in the second orthogonal direction Y2. ○ At least a part of the insulating portion 55 in the first embodiment and the third embodiment may be an adhesive portion 55b adhered to the main body portion 53 and the exposed surface 22b.

[0121] ○ In the second embodiment, the main body portion 53 may employ an adhesive portion 55b that is adhered to the main body portion 53 and the exposed surface 22b instead of at least a part of the insulating portion 55. In the second embodiment, the main body portion 53 may employ the insulating portion 55 instead of at least a part of the adhesive portion 55b. In short, the insulating portion 55 does not necessarily have to have the adhesive portion 55b that is adhered to the main body portion 53 and the exposed surface 22b.

[0122] ○ In the current collector plate 50, the dimension of the first end portion 53a in the first orthogonal direction Y1 and the dimension of the second end portion 53b in the second orthogonal direction Y2 may be the same as each other. In this case, the main body portion 53 is, for example, square when viewed from the stacking direction X.

[0123] ○ In the second embodiment, the main body portion 53 may be in a frame shape other than rectangular when viewed from the stacking direction X. For example, when viewed from the stacking direction X, the main body portion 53 may be in a triangular frame shape, or may be in a polygonal frame shape having five or more corners. For example, when viewed from the stacking direction X, the main body portion 53 may be in a circular frame shape.

[0124] ○ In the first embodiment and the third embodiment, the main body portion 53 may have a shape other than rectangular when viewed from the stacking direction X. For example, when viewed from the stacking direction X, the main body portion 53 may be triangular, or may have a shape having five or more corners. For example, when viewed from the stacking direction X, the main body portion 53 may be circular.

[0125] ○ In the first embodiment and the third embodiment, the shape of the first non-contact region 83a may be changed so as to occupy a dimension of 20% or more and 40% or less of the first dimension L1 of the first side portion 81. The shape of the second non-contact region 83b may be changed so as to occupy a dimension of 20% or more and 40% or less of the second dimension L2 of the second side portion 82.

[0126] ○ The power storage device 100 may include a restraining member that restrains the laminate 10a. The restraining member applies a restraining load in the stacking direction X to the region where the positive electrode active material layer 23 and the negative electrode active material layer 33 overlap when viewed from the stacking direction X of the laminate 10a. Examples of the restraining member include a configuration including restraining plates disposed on one side and the other side of the current collector plate 50 in the stacking direction X, and a fastening member including bolts and nuts for fastening the restraining plates together. In the case of this restraining member, the fastening member biases the restraining plates in a direction approaching each other, thereby applying a restraining load in the stacking direction X to the laminate 10a via the current collector plate 50.

[0127] ○ The power storage device 100 may be a secondary battery other than a lithium ion secondary battery such as a nickel metal hydride secondary battery, for example. The power storage device 100 may be an electric double layer capacitor or an all-solid-state battery.

Explanation of Reference Numerals

[0128] X... Stacking direction, Y... Orthogonal direction, Y1... First orthogonal direction, Y2... Second orthogonal direction, 10a... Laminate, 11... Electrode, 12... Current collector, 15... Sealing body, 22... Terminal current collector, 22a... Covering surface (as the surface provided with the active material layer), 22b... Exposed surface, 23... Positive electrode active material layer (as the active material layer), 33... Negative electrode active material layer (as the active material layer), 36... Positive electrode terminal electrode (as the terminal electrode), 37... Negative electrode terminal electrode (as the terminal electrode), 50... Current collector plate, 53... Main body portion, 53a... First end portion (as the end portion of the main body portion), 53b... Second end portion (as the end portion of the main body portion), 53h... Internal region, 54... Tab portion, 55b... Adhesive portion, 55c... First insulating portion, 55d... Second insulating portion, 80... Frame-shaped region, 80a... Side portion, 80b... Corner portion, 81... First side portion, 82... Second side portion, 83a... First non-contact region, 83b... Second non-contact region, 100... Power storage device, 153... Contact region, 253... Non-contact region.

Claims

1. A laminate having a current collector provided with active material layers of different polarities on one surface and the other surface, and a plurality of electrodes laminated in the stacking direction, and a terminal current collector having the active material layer provided on one side and laminated so as to sandwich the plurality of electrodes in the stacking direction. A pair of terminal electrodes, and, A sealing body that is disposed so as to surround the periphery of the active material layer and seals between the current collectors adjacent to each other in the stacking direction and between the current collector and the terminal current collector adjacent to each other in the stacking direction. A pair of current collector plates that sandwich the laminate in the stacking direction and are in conduction with the terminal electrodes and the plurality of electrodes by contacting the terminal current collector. A power storage device comprising a first insulating portion having insulation disposed between the laminate and the current collector plate in the stacking direction. The terminal current collector has an exposed surface that is a surface on the opposite side of the surface provided with the active material layer of the two surfaces of the terminal current collector and is exposed from the sealing body. The current collector plate has a conductive main body portion and a tab portion that protrudes from an end portion of the main body portion in a direction orthogonal to the stacking direction and has conductivity. The main body portion has a contact region that overlaps and contacts the exposed surface in the stacking direction, and a non-contact region that overlaps the exposed surface through the first insulating portion and does not contact the exposed surface in the stacking direction. Charging and discharging are performed through the tab portion in the power storage device. The non-contact region includes a portion of the main body portion to which the tab portion is connected when viewed from the stacking direction. A power storage device characterized by this.

2. The main body portion has a frame-shaped region that overlaps the active material layer when viewed from the stacking direction. The frame-shaped region is composed of the contact region and the non-contact region. The power storage device includes a second insulating portion that contacts the exposed surface and has insulation. The power storage device according to claim 1, wherein the second insulating portion is disposed inside the frame-shaped region when viewed from the stacking direction.

3. The second insulating portion has an adhesive portion that is adhered to the main body portion and the exposed surface, The power storage device according to claim 2, wherein the adhesive portion is surrounded by the frame-shaped region when viewed from the stacking direction.

4. The main body portion is rectangular when viewed from the stacking direction, The frame-shaped region is a rectangular frame shape composed of four side portions extending along the end portions of the main body portion in the orthogonal direction when viewed from the stacking direction, Among the four side portions, when two side portions extending from a common corner portion are defined as a first side portion and a second side portion, The contact region is located at the entire two side portions other than the first side portion and the second side portion among the four side portions, a part of the first side portion, and a part of the second side portion, The non-contact region includes a first non-contact region located at a portion of the first side portion that is not the contact region and a second non-contact region located at a portion of the second side portion that is not the contact region, The first non-contact region and the second non-contact region extend from the corner portion, Among the orthogonal directions, when the direction in which the first side portion extends is defined as a first orthogonal direction and the direction in which the second side portion extends is defined as a second orthogonal direction, The first non-contact region occupies a dimension of 20% or more and 40% or less of the dimension of the first side portion in the first orthogonal direction, The power storage device according to claim 2 or claim 3, wherein the second non-contact region occupies a dimension of 20% or more and 40% or less of the dimension of the second side portion in the second orthogonal direction.

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