Energy storage module

Abstract

An electric power storage module (1) is provided with a sheet member (30), which comprises a metal layer (41), so that an outer lateral surface (10s) of a multilayer body (10) is covered by the sheet member (30). Consequently, ingress of moisture into the multilayer body (10) is suppressed in comparison to the cases where a sheet that is composed only of a resin layer is provided. Specifically, the sheet member (30) extends from a position on a collector (15) of a positive terminal electrode (13) to a position on a collector (15) of a negative terminal electrode (12) via the outer lateral surface (10s), while being divided into a first portion (31) and a second portion (32), which partially overlap with each other, in a cross-section along the stacking direction (D). In addition, the first portion (31) and the second portion (32) are electrically insulated from each other.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes an assembled battery. This assembled battery is formed by stacking a plurality of sheet-shaped polymer secondary batteries (elementary batteries) and connecting each elementary battery in series. This assembled battery includes an upper exterior plate made of metal that also serves as a positive electrode current collector, a lower exterior plate made of metal that also serves as a negative electrode current collector, and an intermediate exterior plate made of metal that also serves as a positive and negative electrode current collector. Between the upper exterior plate and the intermediate exterior plate, and between the lower exterior plate and the intermediate exterior plate, rectangular frame-shaped resin sealing bodies are respectively provided. The sealing bodies are heat-welded to each exterior plate. A power generation element is disposed in the space surrounded by each exterior plate and the sealing body. The power generation element is composed of a positive electrode layer, a negative electrode layer, and a gel-like electrolyte layer interposed between the positive electrode layer and the negative electrode layer. The gel-like electrolyte layer contains a non-aqueous electrolyte and a polymer that holds this electrolyte.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, in a non-aqueous secondary battery in which the electrolyte is composed of a non-aqueous electrolyte, it is known that the battery performance deteriorates due to the intrusion of moisture into the battery. Specifically, when moisture enters the battery, the electrolyte may deteriorate and the resistance may increase, or the active material and the film may be decomposed by the deteriorated components, resulting in a decrease in battery performance. Therefore, in a non-aqueous secondary battery, it is important to ensure the airtightness of the battery exterior material in order to suppress the intrusion of moisture such as atmospheric humidity. In the assembled battery described in Patent Document 1, each power generation element is sealed with a metal exterior plate and a resin frame-shaped sealing body. However, it is known that resin allows moisture to permeate more easily than metal. Sealing with a resin frame-shaped sealing body may not be able to sufficiently suppress the intrusion of moisture from the outside.

[0005] An object of the present disclosure is to provide a power storage module capable of suppressing moisture intrusion while suppressing short circuit.

Means for Solving the Problems

[0006] The energy storage module according to the present disclosure includes a laminate having an outer surface, and a sheet member provided in close contact with the laminate so as to cover the outer surface in a cross-section along the stacking direction of the laminate. The sheet member includes a metal layer and a first insulating layer laminated on the metal layer and disposed on the outer surface side of the metal layer. The laminate has a plurality of electrodes stacked along the stacking direction, a sealing portion, and an electrolyte. Each of the electrodes includes a current collector, and the electrolyte is accommodated in a space between adjacent current collectors in the stacking direction. The sealing portion is a frame-shaped member for sealing the electrolyte in the space. The electrodes include a plurality of bipolar electrodes, a positive terminal electrode, and a negative terminal electrode. Each of the bipolar electrodes has a current collector, a positive electrode active material layer provided on one surface of the current collector, and a negative electrode active material layer provided on the other surface of the current collector. The positive electrode active material layer and the negative electrode active material layer are stacked so as to face each other. The positive terminal electrode has a current collector and a positive electrode active material layer provided on one surface of the current collector, and is stacked on the bipolar electrode at one end in the stacking direction of the laminate. The negative terminal electrode has a current collector and a negative electrode active material layer provided on the other surface of the current collector, and is stacked on the bipolar electrode at the other end in the stacking direction of the laminate. The sealing portion has a plurality of first resin layers in a frame shape provided at the peripheral edges of the respective current collectors, and a second resin layer that seals the space by welding the ends of the plurality of first resin layers on the side opposite to the space of each other. The outer surface includes an end surface on the side opposite to the space in the second resin layer, a first surface that is the outer surface in the stacking direction of the first resin layer provided on the current collector of the positive terminal electrode, and a second surface that is the outer surface in the stacking direction of the first resin layer provided on the current collector of the negative terminal electrode. The outer surfaces in the stacking direction of the current collectors of the positive terminal electrode and the negative terminal electrode respectively include exposed portions exposed to the outside from the sealing portion. The sheet member extends from the first surface through the end surface to the second surface, and is divided into a plurality of portions insulated from each other in a cross-section along the stacking direction.

[0007] In this power storage module, the laminate includes a plurality of bipolar electrodes, a positive terminal electrode, and a negative terminal electrode. In the laminate, a frame-shaped sealing portion for sealing an electrolyte is provided in a space between current collectors of each electrode. The sealing portion includes a first resin layer provided on each current collector and a second resin layer that seals the space by welding outer ends of the first resin layer to each other. The outer surface of the laminate includes a first surface, a second surface, and an end surface. The first surface and the second surface are outer surfaces in the stacking direction of the first resin layer provided on each of the positive terminal electrode and the negative terminal electrode. The end surface is an outer surface of the second resin layer. And a sheet member including a metal layer is provided in close contact so as to cover the outer surface of this laminate. Since the metal layer included in the sheet member has high barrier properties against moisture, moisture intrusion is suppressed as compared with the case of only a resin layer. In particular, the sheet member extends from the first surface through the end surface to the second surface, and is divided into a plurality of mutually insulated portions in a cross section along the stacking direction. Therefore, although the outer surfaces of the current collectors of the positive terminal electrode and the negative terminal electrode include exposed portions exposed to the outside from the sealing portion, short circuit between the positive terminal electrode and the negative terminal electrode is suppressed through this sheet member. Thus, according to this power storage module, short circuit can also be suppressed when suppressing moisture intrusion.

[0008] In the power storage module according to the present disclosure, adjacent ones of the plurality of portions of the divided sheet member may include overlapping portions that overlap each other. In this case, by overlapping the plurality of portions of the sheet member, the exposed portion of the sealing portion from the sheet member is reduced, and intrusion of not only moisture but also air (nitrogen, oxygen, etc.) is suppressed.

[0009] In the power storage module according to the present disclosure, adjacent portions among a plurality of portions of the divided sheet member are separated from each other such that a gap is formed between their end portions, and an insulating member may be disposed in the gap. Thus, when the plurality of portions of the sheet member are separated from each other, breakage of the metal layer due to the sheet member being deformed as it follows the expansion and contraction of the sealing portion due to heat is surely suppressed. Further, gas generated inside the sheet member escapes from the gap, thereby suppressing an increase in internal pressure.

[0010] In the power storage module according to the present disclosure, the sealing portion includes a plurality of frame-shaped third resin layers, the third resin layers are disposed so as to be interposed between adjacent first resin layers in the stacking direction, and the second resin layer may seal the space by welding the end portions on the opposite side of each space of the plurality of first resin layers and the plurality of third resin layers. In this case, a plurality of spaces can be sealed at once by the second resin layer integrally formed along the stacking direction, and the manufacturing is easy.

[0011] In the power storage module according to the present disclosure, the sheet member includes a second insulating layer laminated on the metal layer on the side opposite to the first insulating layer, and at the overlapping portion, electrical insulation may be formed by overlapping the first insulating layer of one portion and the second insulating layer of another portion adjacent to the one portion. In this case, since the metal layer is interposed between the two insulating layers, insulation can be easily ensured by overlapping each portion of the sheet member.

[0012] In the power storage module according to the present disclosure, at the overlapping portion, one portion relatively vertically above may be overlapped on another portion relatively vertically below. In this case, it is possible to suppress the storage of water flowing from vertically above to vertically below at the overlapping portion of each portion of the sheet member.

[0013] In the power storage module according to the present disclosure, an insulating tape adhered to the sheet member so as to cover the overlapping portion may be provided. In this case, peeling can be prevented at the overlapping portion of each portion of the sheet member, and moisture intrusion can be surely suppressed.

[0014] In the power storage module according to the present disclosure, the plurality of portions include a first portion extending from the first surface to the end surface and a second portion extending from the second surface to the end surface, and the first portion and the second portion may overlap each other on the end surface.

[0015] Further, in the power storage module according to the present disclosure, the plurality of portions include a first portion disposed on the first surface, a second portion disposed on the second surface, and a third portion extending from the end surface so as to overlap each of the first portion and the second portion. At the overlapping portions of each of the first portion and the second portion with the third portion, the third portion may be overlapped outside the first portion and the second portion.

[0016] Further, in the power storage module according to the present disclosure, the plurality of portions include a first portion disposed on the first surface, a second portion disposed on the second surface, and a third portion extending from the end surface so as to overlap each of the first portion and the second portion. At the overlapping portion of the first portion and the third portion, in the cross section along the stacking direction, the end of the third portion is in contact with the end of the first portion such that the end of the third portion is closer to the stacked body side than the end of the first portion. At the overlapping portion of the second portion and the third portion, in the cross section along the stacking direction, the end of the third portion may be in contact with the end of the second portion such that the end of the third portion is closer to the stacked body side than the end of the second portion.

[0017] Furthermore, in the power storage module according to the present disclosure, the plurality of portions may include a first portion extending from one of the first surface and the second surface so as to cover the end surface, and a second portion extending from the other of the first surface and the second surface toward the first portion. As described above, various modes of dividing the sheet member can be considered in order to suppress short circuits and suppress moisture intrusion.

[0018] In the power storage module according to the present disclosure, the current collector includes a first region in which a positive electrode active material layer and a negative electrode active material layer are formed as viewed from the stacking direction, a second region located outside the first region as viewed from the stacking direction, and a third region located outside the second region as viewed from the stacking direction and in which a first resin layer is formed. The sheet member may extend so as to reach the vicinity of the boundary between the third region and the second region as viewed from the stacking direction. In this case, the sheet member is disposed on the first resin layer so that its end does not reach the second region. By covering a wide range of the sealing portion with the sheet member, it is possible to more effectively suppress the intrusion of moisture into the laminate while suppressing a short circuit between the positive electrode terminal electrode and the negative electrode terminal electrode.

[0019] In the power storage module according to the present disclosure, the laminate has a rectangular shape having four side portions as viewed from the stacking direction, and the sheet member may be provided along at least one of the four side portions as viewed from the stacking direction. In this way, it is sufficient that the sheet member is provided on at least one side portion of the laminate as viewed from the stacking direction.

[0020] In the power storage module according to the present disclosure, the sheet member is divided into a plurality of fourth portions as viewed from the stacking direction, and the ends of adjacent fourth portions may be overlapped with each other to form an overlapping portion as viewed from the stacking direction. In this case, in the configuration in which the sheet member is divided into a plurality of portions as viewed from the stacking direction, it is possible to suppress the formation of a conductive path due to the entry of condensed water between the portions.

Advantages of the Invention

[0021] According to the present disclosure, it is possible to provide a power storage module capable of suppressing moisture intrusion while suppressing a short circuit.

Brief Description of the Drawings

[0022]

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[0023] Hereinafter, an embodiment according to the present disclosure will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements may be denoted by the same reference numerals, and redundant descriptions may be omitted.

[0024] FIG. 1 is a schematic cross-sectional view of a power storage module according to an embodiment. FIG. 2 is a cross-sectional view showing an enlarged area AR of FIG. 1. The power storage module 1 shown in FIGS. 1 and 2 is a power storage module used for batteries of various vehicles such as forklifts, hybrid vehicles, and electric vehicles, for example. The power storage module 1 is a secondary battery such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery, for example. The power storage module 1 may be an electric double layer capacitor or an all-solid-state battery. Here, the case where the power storage module 1 is a lithium-ion secondary battery is illustrated.

[0025] The energy storage module 1 includes a laminate 10 and a sheet member 30. The laminate 10 has a plurality of electrodes, a plurality of separators 14, a sealing portion 20, and an electrolyte (not shown). The plurality of electrodes includes a plurality of bipolar electrodes 11, a negative terminal electrode 12, and a positive terminal electrode 13.

[0026] Each of the plurality of bipolar electrodes 11 has a current collector 15, a positive electrode active material layer 16, and a negative electrode active material layer 17. The current collector 15 has, for example, a rectangular sheet shape. The positive electrode active material layer 16 is provided on one surface 15a of the current collector 15. The negative electrode active material layer 17 is provided on the other surface 15b of the current collector 15. The plurality of bipolar electrodes 11 are laminated such that the positive electrode active material layer 16 of one bipolar electrode 11 faces the negative electrode active material layer 17 of another bipolar electrode 11. Here, the direction in which the bipolar electrodes 11 are laminated is referred to as the lamination direction D. One surface 15a of the current collector 15 is a surface facing one side in the lamination direction D, and the other surface 15b of the current collector 15 is a surface facing the other side in the lamination direction D.

[0027] The positive electrode active material layer 16 and the negative electrode active material layer 17 are rectangular when viewed from the lamination direction D. The negative electrode active material layer 17 is slightly larger than the positive electrode active material layer 16 when viewed from the lamination direction D. That is, in a plan view when viewed from the lamination direction D, the entire formation region of the positive electrode active material layer 16 is located within the formation region of the negative electrode active material layer 17.

[0028] The negative terminal electrode 12 has a current collector 15 and a negative electrode active material layer 17 provided on the other surface 15b of the current collector 15. The negative terminal electrode 12 does not have a positive electrode active material layer 16 and a negative electrode active material layer 17 on one surface 15a of the current collector 15. That is, no active material layer is provided on one surface 15a of the current collector 15 of the negative terminal electrode 12. The negative terminal electrode 12 is laminated on the bipolar electrode 11 at one end in the lamination direction D of the laminate 10. The negative terminal electrode 12 is laminated on the bipolar electrode 11 such that its negative electrode active material layer 17 faces the positive electrode active material layer 16 of the bipolar electrode 11. Therefore, one surface 15a of the current collector 15 of the negative terminal electrode 12 faces the outside of the laminate 10, and a part thereof is exposed outside the laminate 10.

[0029] The positive terminal electrode 13 has a current collector 15 and a positive electrode active material layer 16 provided on one surface 15a of the current collector 15. The positive terminal electrode 13 does not have the positive electrode active material layer 16 and the negative electrode active material layer 17 on the other surface 15b of the current collector 15. That is, no active material layer is provided on the other surface 15b of the current collector 15 of the positive terminal electrode 13. The positive terminal electrode 13 is laminated on the bipolar electrode 11 at the other end in the lamination direction D of the laminate 10. The positive terminal electrode 13 is laminated on the bipolar electrode 11 such that its positive electrode active material layer 16 faces the negative electrode active material layer 17 of the bipolar electrode 11. Therefore, the other surface 15b of the current collector 15 of the positive terminal electrode 13 faces the outside of the laminate 10, and a part thereof is exposed to the outside of the laminate 10.

[0030] The separator 14 is disposed between adjacent bipolar electrodes 11, between the negative terminal electrode 12 and the bipolar electrode 11, and between the positive terminal electrode 13 and the bipolar electrode 11. The separator 14 is interposed between the positive electrode active material layer 16 and the negative electrode active material layer 17. The separator 14 prevents a short circuit due to contact of adjacent electrodes by isolating the positive electrode active material layer 16 and the negative electrode active material layer 17. The separator 14 allows charge carriers such as lithium ions to pass through.

[0031] The current collector 15 is a chemically inert electrical conductor for continuously passing an electric current through the positive electrode active material layer 16 and the negative electrode active material layer 17 during discharge or charging of the lithium ion secondary battery. The material of the current collector 15 is, for example, a metal material, a conductive resin material, or a conductive inorganic material. Examples of the conductive resin material include a conductive polymer material or a resin obtained by adding a conductive filler to a non-conductive polymer material as necessary. The current collector 15 may include a plurality of layers. In this case, each layer of the current collector 15 may contain the above metal material or conductive resin material.

[0032] A coating layer may be formed on the surface of the current collector 15. The coating layer may be formed by a known method such as plating or spray coating. The current collector 15 may have, for example, a plate shape, a foil shape (e.g., a metal foil), a film shape, or a mesh shape. Examples of the metal foil include aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil. Examples of the stainless steel foil include SUS 304, SUS 316, or SUS 301 defined in JIS G 4305:2015. By using a stainless steel foil as the current collector 15, the mechanical strength of the current collector 15 can be ensured. The current collector 15 may be an alloy foil or a clad foil of the above metals. When the current collector 15 has a foil shape, the thickness of the current collector 15 may be, for example, 1 μm to 100 μm.

[0033] The positive electrode active material layer 16 contains a positive electrode active material capable of occluding and releasing charge carriers such as lithium ions. Examples of the positive electrode active material include lithium composite metal oxides having a layered rock salt structure, metal oxides having a spinel structure, and polyanion-based compounds. The positive electrode active material may be any material that can be used in a lithium ion secondary battery. The positive electrode active material layer 16 may contain a plurality of positive electrode active materials. In the present embodiment, the positive electrode active material layer 16 contains olivine-type lithium iron phosphate (LiFePO4) as a composite oxide.

[0034] The negative electrode active material layer 17 contains a negative electrode active material capable of occluding and releasing charge carriers such as lithium ions. The negative electrode active material may be any of a single substance, an alloy, or a compound. Examples of the negative electrode active material include Li, carbon, and metal compounds. The negative electrode active material may also be an element capable of alloying with lithium or a compound thereof. Examples of carbon include natural graphite, artificial graphite, hard carbon (carbon with low graphitization property), or soft carbon (carbon with high graphitization property). Examples of artificial graphite include highly oriented graphite and mesocarbon microbeads. Examples of elements capable of alloying with lithium include silicon or tin. In the present embodiment, the negative electrode active material layer 17 contains graphite as a carbon-based material.

[0035] Each of the positive electrode active material layer 16 and the negative electrode active material layer 17 (hereinafter sometimes simply referred to as the "active material layer") may further contain a conductive assistant, a binder, an electrolyte (polymer matrix, ion conductive polymer, electrolyte solution, etc.), an electrolyte supporting salt (lithium salt, etc.) for enhancing ion conductivity, etc., as necessary. The conductive assistant is added to enhance the conductivity of each electrode (bipolar electrode 11, negative electrode terminal electrode 12, positive electrode terminal electrode 13). Examples of the conductive assistant include acetylene black, carbon black, or graphite.

[0036] Examples of the binder include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber, thermoplastic resins such as polypropylene and polyethylene, imide-based resins such as polyimide and polyamideimide, alkoxysilyl group-containing resins, acrylic resins such as acrylic acid or methacrylic acid, styrene-butadiene rubber (SBR), carboxymethyl cellulose, alginates such as sodium alginate and ammonium alginate, water-soluble cellulose ester cross-linked products, starch-acrylic acid graft polymers, etc. These binders can be used alone or in combination. Examples of the solvent include water, N-methyl-2-pyrrolidone (NMP), etc.

[0037] The separator 14 may be, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains an electrolyte. Examples of the material of the separator 14 include polypropylene, polyethylene, polyolefin, polyester, and the like. The separator 14 may have a single-layer structure or a multilayer structure. The multilayer structure may have, for example, an adhesive layer or a ceramic layer as a heat-resistant layer. The separator 14 may be impregnated with an electrolyte. The separator 14 may be composed of an electrolyte such as a polymer electrolyte or an inorganic-type electrolyte. Examples of the electrolyte impregnated in the separator 14 include a liquid electrolyte (electrolyte solution) 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.

[0038] When the separator 14 is impregnated with an electrolyte solution, known lithium salts such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, LiN(CF3SO2)2 may be used as the electrolyte salt. Further, as the non-aqueous solvent, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, ethers may be used. Note that two or more of these known solvent materials may be used in combination.

[0039] The sealing portion 20 is formed in a frame shape at the peripheral edge of the laminate 10 so as to surround the laminate 10. The sealing portion 20 can be joined to each of one surface 15a and the other surface 15b of each current collector 15 at the peripheral edge 15c of each current collector 15. The sealing portion 20 seals each of the spaces S between the current collectors 15 adjacent to each other in the stacking direction D. An electrolyte is accommodated in each space S. When the electrolyte is liquid, the sealing portion 20 prevents the electrolyte from permeating to the outside. The sealing portion 20 suppresses the intrusion of moisture and the like from the outside of the laminate 10 into the space S. The sealing portion 20 prevents, for example, the gas generated at each electrode due to charge and discharge reactions and the like from leaking to the outside of the power storage module 1. The edge portions of each separator 14 are joined to the sealing portion 20. The sealing portion 20 contains an insulating material. Examples of the material of the sealing portion 20 include various resin materials such as polypropylene, polyethylene, polystyrene, ABS resin, acid-modified polypropylene, acid-modified polyethylene, and acrylonitrile styrene resin.

[0040] The sealing portion 20 includes a plurality of first resin layers 21, second resin layers 22, and a plurality of third resin layers 23. The first resin layers 21 are provided on each of the current collectors 15. Therefore, the plurality of first resin layers 21 are stacked on each other along the stacking direction D. The first resin layer 21 is in a frame shape. The first resin layer 21 is provided at the peripheral edge 15c of the current collector 15. That is, the first resin layer 21 is provided so as to extend from one surface 15a of the current collector 15 through the end face to the other surface 15b and covers the peripheral edge 15c. The first resin layer 21 can be welded to at least one of one surface 15a and the other surface 15b of the current collector 15.

[0041] Each of the multiple third resin layers 23 is disposed so as to be interposed between the first resin layers 21 adjacent to each other in the stacking direction D. As a result, the multiple third resin layers 23 hold a space between the adjacent first resin layers 21, i.e., between the adjacent current collectors 15. The third resin layer 23 is frame-shaped. The third resin layer 23 is disposed on the peripheral portion 15c of the current collector 15 as viewed from the stacking direction D. The third resin layer 23 can be welded to at least one of the pair of first resin layers 21 adjacent to each other in the stacking direction D. Here, the end of the separator 14 is sandwiched and fixed between the first resin layer 21 and the third resin layer 23.

[0042] The second resin layer 22 is an end surface welding layer formed by welding and integrating the overlapping portions of the multiple first resin layers 21 and the multiple third resin layers 23 in the stacking direction D. When viewed from the stacking direction D, the second resin layer 22 has a frame shape surrounding the laminate 10. In the second resin layer 22, the ends of the multiple adjacent first resin layers 21 and the ends of the multiple adjacent third resin layers 23 are welded and integrated. This seals the space S formed between the adjacent electrodes with the separator 14 in between. An end surface 22s of the second resin layer 22 opposite to the space S constitutes a part of the outer surface 10s of the laminate 10.

[0043] That is, the outer side surface 10s of the laminate 10 includes the end surface 22s, the first surface 21a, and the second surface 21b. The first surface 21a is the outer surface in the stacking direction D of the first resin layer 21 provided on the current collector 15 of the positive terminal electrode 13. The second surface 21b is the outer surface in the stacking direction D of the first resin layer 21 provided on the current collector 15 of the negative terminal electrode 12. That is, the outer side surface 10s of the laminate 10 is the outer side surface of the sealing portion 20.

[0044] One surface 15a of the negative terminal electrode 12 facing the outside of the laminate 10 includes an exposed portion 15d exposed to the outside from the sealing portion 20 (the first resin layer 21). The exposed portion 15d of the negative terminal electrode 12 is a portion other than the second surface 21b of the current collector 15 of the negative terminal electrode 12 (a portion that does not overlap the second surface 21b) when viewed from the lamination direction D. Further, the other surface 15b of the positive terminal electrode 13 facing the outside of the laminate 10 includes an exposed portion 15d exposed to the outside from the sealing portion 20 (the first resin layer 21). The exposed portion 15d of the positive terminal electrode 13 is a portion other than the first surface 21a of the current collector 15 of the positive terminal electrode 13 (a portion that does not overlap the first surface 21a) when viewed from the lamination direction D. The exposed portions 15d provided on the negative terminal electrode 12 and the positive terminal electrode 13 function as terminals for extracting current from the power storage module 1. In the power storage module 1, a conductive member 50 is disposed and electrically connected to these exposed portions 15d. The conductive member 50 is used to electrically connect a plurality of power storage modules 1. Further, the conductive member 50 can also be used as a restraint member to apply a restraint load to the laminate 10.

[0045] A cooling flow path may be formed in the conductive member 50. By flowing a cooling medium through the cooling flow path formed in the conductive member 50, the laminate 10 can be cooled. In other words, coolers are arranged with respect to the exposed portions 15d of the outer surface of the current collector 15 at both ends in the lamination direction D of the laminate 10. In this case, at both ends in the lamination direction D of the laminate 10, dew condensation water is likely to occur around the conductive member 50 as compared with other portions.

[0046] The sheet member 30 is disposed in close contact with the laminate 10 so as to cover the outer surface 10s of the laminate 10. The sheet member 30 includes at least a metal layer 41 and a first insulating layer 42 laminated on the metal layer 41. In the present embodiment, the sheet member 30 further includes a second insulating layer 43 laminated on the metal layer 41 on the opposite side of the first insulating layer 42. The second insulating layer 43 is provided on the other surface of the metal layer 41 opposite to the one surface where the first insulating layer 42 is provided. That is, the sheet member 30 is configured by sandwiching the metal layer 41 with the first insulating layer 42 and the second insulating layer 43. The sheet member 30 is provided on the laminate 10 such that the first insulating layer 42 is on the outer surface 10s side of the laminate 10. Here, the first insulating layer 42 is in contact with the outer surface 10s. In the sheet member 30, the first insulating layer 42 may function as an adhesive layer for the outer surface 10s. Alternatively, another adhesive layer may be interposed between the sheet member 30 and the outer surface 10s.

[0047] The first insulating layer 42 is made of a resin having insulating properties. The material of the first insulating layer 42 is, for example, polypropylene, polyethylene, polyamide, or the like. The material of the first insulating layer 42 can be selected from the same type of material as the sealing portion 20 from the viewpoint of adhesiveness to the sealing portion 20. The metal layer 41 is made of a material having low water permeability (small water permeability coefficient), such as aluminum foil or stainless steel foil. The second insulating layer 43 is made of, for example, a resin having insulating properties. The material of the second insulating layer 43 is, for example, polypropylene, polyethylene, polyamide, nylon, or the like. As an example, the sheet member 30 may be an aluminum laminate sheet, and polypropylene may be selected as the first insulating layer 42, aluminum as the metal layer 41, and polyethylene terephthalate as the second insulating layer 43.

[0048] The sheet member 30 includes a portion 30a located on the first surface 21a on the positive electrode terminal electrode 13 side, a portion 30s located on the end surface 22s, and a portion 30b located on the second surface 21b on the negative electrode terminal electrode 12 side. Thereby, the sheet member 30 extends from the first surface 21a through the end surface 22s to the second surface 21b. As shown in FIG. 3, the current collector 15 of the negative electrode terminal electrode 12 includes a first region A1, a second region A2, and a third region A3. The first region A1 is a region where the negative electrode active material layer 17 is formed as viewed from the stacking direction D. The second region A2 is located outside the first region A1 as viewed from the stacking direction D and is a region where the negative electrode active material layer 17 is not formed. The third region A3 is located outside the second region A2 as viewed from the stacking direction D and is a region where the first resin layer 21 is formed. Similarly, the current collector 15 of the positive electrode terminal electrode 13 includes a first region A1, a second region A2, and a third region A3. The first region A1 is a region where the positive electrode active material layer 16 is formed as viewed from the stacking direction D. The second region A2 is located outside the first region A1 as viewed from the stacking direction D and is a region where the positive electrode active material layer 16 is not formed. The third region A3 is located outside the second region A2 as viewed from the stacking direction D and is a region where the first resin layer 21 is formed. As an example, the sheet member 30 extends to the vicinity of the boundary between the third region A3 and the second region A2 so as to cover the third region A3 of the current collector 15 as viewed from the stacking direction D.

[0049] On the other hand, the sheet member 30 can be terminated so as not to reach the exposed portion 15d including the first region A1 and the second region A2. In this case, the end portion of the sheet member 30 can be disposed on the third region A3. Here, the end portion of the sheet member 30 is aligned with the inner edge of the third resin layer 23 as viewed from the stacking direction D, but is not limited thereto, and may be located in the third region A3. Note that FIG. 3 is a cross-sectional view showing a part of the power storage module 1 shown in FIG. 1, but the hatching is omitted.

[0050] As shown in FIGS. 1 and 2, the sheet member 30 is divided into a plurality of portions such that at least the metal layer 41 in the portion 30a on the positive electrode terminal electrode 13 side and the metal layer 41 in the portion 30b on the negative electrode terminal electrode 12 side are electrically insulated in a cross section (any cross section including the illustrated cross section) along the stacking direction D. In the present embodiment, the sheet member 30 is divided into a first portion 31 extending from the first surface 21a to the end surface 22s and a second portion 32 extending from the second surface 21b to the end surface 22s in a cross section along the stacking direction D. The first portion 31 and the second portion 32 overlap each other on the end surface 22s. Thereby, the end surface 22s is covered with the sheet member 30. That is, here, the sheet member 30 is divided into a first portion 31 and a second portion 32 that are insulated from each other in a cross section along the stacking direction D. Further, the first portion 31 and the second portion 32 include an overlapping portion P where they overlap each other. At the overlapping portion P of the first portion 31 and the second portion 32, the first insulating layer 42 of the second portion 32 is brought into contact with the second insulating layer 43 of the first portion 31. In the illustrated example, at the overlapping portion P, the end of the second portion 32 is overlapped outside the end of the first portion 31 (on the side opposite to the laminate 10).

[0051] In this way, in the sheet member 30, the first portion 31 and the second portion 32 are electrically insulated. That is, the sheet member 30 is electrically separated in the middle thereof. Therefore, it is possible to prevent the exposed portion 15d of the positive electrode terminal electrode 13 and the exposed portion 15d of the negative electrode terminal electrode 12 from being short-circuited through the metal layer 41 of the sheet member 30. For example, as described above, even if condensed water is generated around the conductive member 50 (cooler) and the condensed water forms a conductive path between the exposed portion 15d of the current collector 15 and the metal layer 41 of the sheet member 30 close to the exposed portion 15d, the sheet member 30 on the positive electrode terminal electrode 13 side and the sheet member 30 on the negative electrode terminal electrode 12 side are separated from each other, so that it is possible to suppress the positive electrode terminal electrode 13 and the negative electrode terminal electrode 12 from being short-circuited through the sheet member 30.

[0052] Here, at the overlapping portion P between the first part 31 and the second part 32, the second part 32, which is relatively arranged vertically above during the use of the power storage module 1, is overlapped on top of (on the side opposite to the laminate 10, outside) the first part 31, which is relatively arranged vertically below. Therefore, it becomes difficult for water flowing vertically downward to be stored at the overlapping portion P. Further, in the power storage module 1, an insulating tape 45 may be attached to the sheet member 30 so as to cover the overlapping portion P (so as to span from the second part 32 to the first part 31). Thereby, at the overlapping portion P, the intrusion of water from between the first part 31 and the second part 32 into the inside of the sheet member 30 is suppressed. Also, the curling and peeling between the first part 31 and the second part 32 are suppressed.

[0053] Here, as shown in FIG. 4, the laminate 10 (outer surface 10s) has a polygonal shape having a plurality of side portions when viewed from the lamination direction D. Here, the laminate 10 is a rectangular shape having four side portions when viewed from the lamination direction D. And the sheet member 30 is formed in a rectangular frame shape when viewed from the lamination direction D, and is composed of four portions (fourth portions) 30A, 30B, 30C, 30D along each of the four side portions. In other words, the sheet member 30 is composed of four portions 30A to 30D that cover each of the four side surfaces of the rectangular tube-shaped outer surface 10s. That is, the sheet member 30 may be divided into a plurality of fourth portions when viewed from the lamination direction D. That is, the first part 31 and the second part 32 of the sheet member 30 may each be divided into four portions (fourth portions) 30A, 30B, 30C, 30D along each of the four side portions when viewed from the lamination direction D. In a region including the corner where two side surfaces of the outer surface 10s intersect when viewed from the lamination direction D, for example, at least a part of the sheet member 30 (for example, part 30A and part 30B) provided on two side portions of the laminate 10 overlaps each other to form an overlapping portion Q. That is, the ends of adjacent fourth portions when viewed from the lamination direction D may overlap each other to form an overlapping portion Q. Thereby, the formation of a conductive path due to the entry of condensed water between the respective parts is suppressed.

[0054] As described above, in the power storage module 1 according to the present embodiment, the laminate 10 includes a plurality of bipolar electrodes 11, a positive terminal electrode 13, and a negative terminal electrode 12. In the laminate 10, a frame-shaped sealing portion 20 for sealing an electrolyte is provided in a space S between current collectors 15 of each electrode. The sealing portion 20 includes a first resin layer 21 provided on each of the current collectors 15 and a second resin layer 22 that seals the space S by welding outer ends of the first resin layer 21 to each other. The outer surface 10s of the laminate 10 includes a first surface 21a, a second surface 21b, and an end surface 22s. The first surface 21a and the second surface 21b are outer surfaces in the stacking direction D of the first resin layer 21 provided on the positive terminal electrode 13 and the negative terminal electrode 12, respectively. The end surface 22s is an outer surface of the second resin layer 22. And a sheet member 30 including a metal layer 41 is provided so as to cover the outer surface 10s of the laminate 10.

[0055] Since the metal layer 41 included in the sheet member 30 has high barrier properties against moisture, moisture intrusion into the laminate 10 is suppressed as compared with the case where a sealing body is formed only of a resin layer. In particular, the sheet member 30 is provided to extend from the first surface 21a through the end surface 22s to the second surface 21b. Therefore, moisture intrusion into the laminate 10 can be effectively suppressed. Further, since the sheet member 30 is provided in close contact with the laminate 10, a space is less likely to be generated between the laminate 10 and the sheet member 30. Therefore, moisture intrusion can be suppressed without increasing the size of the power storage module 1. Further, the sheet member 30 is divided on the end surface 22s into a first portion 31 on the positive terminal electrode 13 side and a second portion 32 on the negative terminal electrode 12 side in a cross section along the stacking direction D. And the first portion 31 and the second portion 32 are electrically insulated from each other. Therefore, although the outer surfaces of the current collectors 15 of the positive terminal electrode 13 and the negative terminal electrode 12 include exposed portions 15d exposed to the outside from the sealing portion 20, short circuit between the positive terminal electrode 13 and the negative terminal electrode 12 is suppressed through this sheet member 30. Thus, according to the power storage module 1, it is possible to suppress moisture intrusion into the laminate 10 while suppressing short circuit between the positive terminal electrode 13 and the negative terminal electrode 12.

[0056] Further, in the power storage module 1, since the sheet member 30 is divided into the first portion 31 and the second portion 32, when the sheet member 30 is provided in close contact with the laminate 10, it may be adhered to the laminate 10 for each respective portion (it may be pasted), and workability is improved. Therefore, when the sheet member 30 is provided, wrinkles are less likely to occur in the metal layer 41 or the like. Further, when using a sheet member including a metal layer (not divided), when the sealing portion expands and contracts due to heat, since the entire sheet member tends to deform following the expansion and contraction, there is a risk that a metal layer that is difficult to deform corresponding to the deformation may break. On the other hand, in the power storage module 1, when the sheet member 30 is divided into the first portion 31 and the second portion 32, since the entire sheet member 30 does not deform so as to follow the expansion and contraction of the sealing portion 20 due to heat, breakage of the metal layer 41 is suppressed.

[0057] Further, in the power storage module 1, the first portion 31 and the second portion 32 of the divided sheet member 30 include an overlapping portion P that overlaps with each other. For this reason, the exposed portion of the sealing portion 20 from the sheet member 30 is reduced, and intrusion of not only moisture but also air (nitrogen, oxygen, etc.) is suppressed.

[0058] Further, in the power storage module 1, the sealing portion 20 includes a plurality of frame-shaped third resin layers 23. The third resin layer 23 is disposed so as to be interposed between adjacent first resin layers 21 in the lamination direction D. The second resin layer 22 seals the space S by welding the opposite ends of each of the spaces S of the plurality of first resin layers 21 and the plurality of third resin layers 23. For this reason, a plurality of spaces S can be sealed at once by the second resin layer 22 formed integrally along the lamination direction D, and its manufacture is easy.

[0059] In the power storage module 1, the sheet member 30 includes a second insulating layer 43 laminated on the metal layer 41 on the side opposite to the first insulating layer 42. At the overlapping portion P between the first portion 31 and the second portion 32, the first insulating layer 42 of the second portion 32 and the second insulating layer 43 of the first portion 31 adjacent to the second portion 32 are overlapped to form electrical insulation. In this way, since the metal layer 41 is interposed between the two-layer first insulating layer 42 and second insulating layer 43, insulation can be easily ensured by overlapping each part of the sheet member 30.

[0060] In the power storage module 1, at the overlapping portion P between the first portion 31 and the second portion 32, the second portion 32 that is relatively vertically above is overlapped on the first portion 31 that is relatively vertically below. Therefore, at the overlapping portion P, the storage of water flowing from vertically above to vertically below is suppressed.

[0061] The power storage module 1 may further include an insulating tape 45 adhered to the sheet member 30 so as to cover the overlapping portion P between the first portion 31 and the second portion 32. In this case, peeling at the overlapping portion P can be prevented, and moisture intrusion can be reliably suppressed.

[0062] In the power storage module 1, the current collector 15 includes a first region A1, a second region A2, and a third region A3. The first region A1 is a region where the positive electrode active material layer 16 and the negative electrode active material layer 17 are formed as viewed from the stacking direction D. The second region A2 is a region located outside the first region A1 as viewed from the stacking direction D. The third region A3 is located outside the second region A2 as viewed from the stacking direction D and is a region where the first resin layer 21 is formed. And the sheet member 30 may extend so as to reach the vicinity of the boundary portion between the third region A3 and the second region A2 as viewed from the stacking direction D. In this case, the sheet member 30 is disposed on the first resin layer 21 so that its end does not reach the second region A2. By covering a wide range of the sealing portion 20 with the sheet member 30, it is possible to more effectively suppress moisture intrusion into the laminate 10 while suppressing a short circuit between the positive electrode terminal electrode 13 and the negative electrode terminal electrode 12.

[0063] Furthermore, in the power storage module 1, the laminate 10 has a rectangular shape with four side portions when viewed from the lamination direction D, and the sheet member 30 is composed of four portions 30A to 30D along each of the four side portions of the laminate 10 when viewed from the lamination direction D. Therefore, the sheet member 30 can be easily configured by preparing a plurality of portions 30A to 30D corresponding to each side portion of the laminate 10 when viewed from the lamination direction D.

[0064] In the power storage module 1, the sheet member 30 is divided into a plurality of fourth portions (portions 30A to 30D) when viewed from the lamination direction D. And when viewed from the lamination direction D, the ends of adjacent fourth portions overlap each other to form an overlapping portion Q. Therefore, in the configuration where the sheet member 30 is divided into a plurality of portions when viewed from the lamination direction D, it is possible to suppress the formation of a conductive path due to the entry of condensed water between the portions.

[0065] The above embodiments have described one aspect of the power storage module according to the present disclosure. The power storage module according to the present disclosure can be arbitrarily modified from the above power storage module 1. Subsequently, modified examples will be described.

[0066] FIG. 5 is a schematic cross-sectional view showing a power storage module 1A according to a first modified example. In the power storage module 1A shown in FIG. 5, the sheet member 30 is divided into three portions: a first portion 33, a second portion 34, and a third portion 35. The first portion 33 is a portion disposed on the first surface 21a, and the second portion 34 is a portion disposed on the second surface 21b. The first portion 33 and the second portion 34 each extend so as to cover the entire first surface 21a and the second surface 21b.

[0067] The third part 35 covers the end face 22s and extends so as to overlap the first part 33 and the second part 34 respectively from the end face 22s. At the overlapping portion P between each of the first part 33 and the second part 34 and the third part 35, the third part 35 is overlapped on each of the first part 33 and the second part 34. That is, at the overlapping portion P between each of the first part 33 and the second part 34 and the third part 35, the third part 35 is overlapped outside the first part 33 and the second part 34. More specifically, at the overlapping portion P between the first part 33 and the third part 35, in the cross section along the lamination direction D, the end of the first part 33 and the end of the third part 35 are in contact with each other such that the end of the first part 33 is closer to the lamination body 10 side than the end of the third part 35. Also, at the overlapping portion P between the second part 34 and the third part 35, in the cross section along the lamination direction D, the end of the second part 34 and the end of the third part 35 are in contact with each other such that the end of the second part 34 is closer to the lamination body 10 side than the end of the third part 35. When viewed from the lamination direction D, the outer edges of each of the first part 33 and the second part 34 only need to be covered by the third part 35. In the cross section along the lamination direction D, the outer edges of each of the first part 33 and the second part 34 are sandwiched between the sealing portion 20 and the third part 35. Here, the third part 35 does not reach the position on the current collector 15, but it may extend to reach the position on the current collector 15.

[0068] FIG. 6 is a schematic cross-sectional view showing the power storage module 1B according to the second modification. In the power storage module 1B shown in FIG. 6, the sheet member 30 is divided into a first portion 33, a second portion 34, and a third portion 35 similar to the power storage module 1A. On the other hand, in the power storage module 1B, at the overlapping portion P between each of the first portion 33 and the second portion 34 and the third portion 35, the third portion 35 is stacked under each of the first portion 33 and the second portion 34. That is, at the overlapping portion P between each of the first portion 33 and the second portion 34 and the third portion 35, the first portion 33 and the second portion 34 are stacked outside the third portion 35. More specifically, at the overlapping portion P between the first portion 33 and the third portion 35, in the cross-section along the stacking direction D, the end of the third portion 35 is in contact with the end of the first portion 33 such that the end of the third portion 35 is closer to the stacked body 10 side than the end of the first portion 33. Also, at the overlapping portion P between the second portion 34 and the third portion 35, in the cross-section along the stacking direction D, the end of the third portion 35 is in contact with the end of the second portion 34 such that the end of the third portion 35 is closer to the stacked body 10 side than the end of the second portion 34. When viewed from the stacking direction D, the outer edge of the third portion 35 may be covered by each of the first portion 33 and the second portion 34. In the cross-section along the stacking direction D, the outer edge of the third portion 35 is sandwiched between each of the first portion 33 and the second portion 34 and the sealing portion 20.

[0069] Furthermore, although not shown, the sheet member 30 may be divided into a first portion disposed on one of the first surface 21a and the second surface 21b, and a second portion extending from the other of the first surface 21a and the second surface 21b through the end surface 22s so as to overlap the first portion. And for either of the power storage modules 1A and 1B, an insulating tape 45 may be attached so as to cover the overlapping portion P.

[0070] As described above, various modes of dividing the sheet member 30 can be considered in order to suppress moisture intrusion while suppressing short circuits. In the above, the example of dividing the sheet member 30 into two and the example of dividing it into three have been described, but the sheet member 30 may be divided into a plurality of four or more parts. That is, it is sufficient that adjacent parts among the plurality of parts of the divided sheet member 30 have an overlapping portion P that overlaps with each other.

[0071] Here, FIG. 7 is a schematic cross-sectional view showing the power storage module 1C according to the third modification. In the above example, the case where the parts of the divided sheet member 30 overlap each other has been described. However, in the example of FIG. 7, although the sheet member 30 is divided into a plurality of parts, the parts do not overlap each other. More specifically, in the power storage module 1C shown in FIG. 7, the sheet member 30 includes a first portion 36 that extends so as to cover the end surface 22s from the first surface 21a, and a second portion 37 that is disposed on the second surface 21b and extends toward the first portion 36. The first portion 36 includes a portion 30a located on the first surface 21a of the sheet member 30 and a portion 30s located on the end surface 22s. The second portion 37 includes a portion 30b located on the second surface 21b (which is the portion 30b). Here, it is sufficient that the second portion 37 is insulated from the first portion 36.

[0072] In the example of FIG. 7, the end portion of the first portion 36 on the end surface 22s side is located at the corner R including the second surface 21b and the end surface 22s in the sealing portion 20. The end portion of the second portion 37 on the end surface 22s side is located at the corner R. And at the corner R, the first portion 36 and the second portion 37 are separated from each other so that a gap G is formed between the end portions of each other. Thereby, the first portion 36 and the second portion 37 are insulated from each other. Note that an insulating member can be disposed in this gap G. In this case, as the insulating member, a liquid insulating resin (for example, liquid silicon) or the like may be provided so as to fill the gap G. Furthermore, a protective tape such as an insulating tape or a metal laminate film (for example, a film having the same layer structure as the sheet member 30) may be attached so as to span the first portion 36 and the second portion 37 via the gap G. By these means, since the end surfaces of the first portion 36 and the second portion 37 sandwiching the gap G are covered with the protective tape, insulation between the first portion 36 and the second portion 37 due to condensation or the like is more surely ensured. The gap G can be set to the minimum length within a range where insulation can be ensured, but it may also be the length at which a part of the outer surface 10s is exposed in consideration of variations during the attachment of the sheet member 30.

[0073] As described above, in the power storage module 1C, the first portion 36 and the second portion 37 of the divided sheet member 30 are separated from each other so that a gap G is formed between the end portions of each other. And an insulating member may be disposed in the gap G. Thus, when the divided portions of the sheet member 30 are separated from each other, breakage of the metal layer 41 due to the sheet member 30 being deformed so as to follow the expansion and contraction of the sealing portion 20 due to heat is surely suppressed. Also, gas generated inside the sheet member 30 escapes from the gap G, thereby suppressing an increase in internal pressure.

[0074] In the example of FIG. 7, the case where the sheet member 30 is divided into two parts, i.e., the first part 36 and the second part 37, and they are separated from each other has been described. However, the sheet member 30 may be divided into three or more parts separated from each other with a gap G therebetween. Further, even when the sheet member 30 is divided into two parts, the position of the division (i.e., the position of the gap G) can be arbitrarily set. For example, the sheet member 30 may be divided into a first part extending from the first surface 21a to the middle of the end face 22s and a second part extending from the second surface 21b to the middle of the end face 22s, and the gap G may be arranged in the middle of the end face 22s.

[0075] FIG. 8 is a schematic cross-sectional view of the power storage module 1D according to the fourth modification. As shown in FIG. 8, in the power storage module 1D, similar to the power storage module 1 shown in FIG. 1, the sheet member 30 is divided into a first part 31 and a second part 32. On the other hand, in the power storage module 1D, the first part 31 and the second part 32 are abutted against each other on the end face 22s. Each of the first part 31 and the second part 32 extends so as to protrude away from the laminate 10 from the abutting part. Then, the first part 31 and the second part 32 are overlapped with each other at the parts protruding from the respective laminates 10 to form an overlapping portion P. At the overlapping portion P, the first part 31 and the second part 32 are electrically insulated from each other by adhesion (e.g., welding) of the respective first insulating layers 42. Thereby, water intrusion into the inside of the sheet member 30 from between the first part 31 and the second part 32 is suppressed at the overlapping portion P.

[0076] FIG. 9 is a schematic cross-sectional view of the power storage module 1E according to the fifth modification. As shown in FIG. 9, in the power storage module 1E, similar to the power storage module 1C shown in FIG. 7, the sheet member 30 is divided into a first portion 36 and a second portion 37. On the other hand, in the power storage module 1E, the first portion 36 and the second portion 37 are abutted against each other at the corner R. Each of the first portion 36 and the second portion 37 extends so as to protrude away from the laminate 10 from the abutting portion (i.e., the corner R). Then, the first portion 36 and the second portion 37 are overlapped with each other at the portions protruding from the respective laminates 10 to form an overlapping portion P. At the overlapping portion P, the first portion 36 and the second portion 37 are electrically insulated from each other by adhering (e.g., welding) the respective first insulating layers 42 to each other. Thereby, water intrusion into the interior of the sheet member 30 from between the first portion 36 and the second portion 37 is suppressed at the overlapping portion P. In the power storage module 1E, when viewed from the stacking direction D, the end of the second portion 37 is located outside the end of the first surface 21a (end face 22s). In other words, at the overlapping portion P of the first portion 36 and the second portion 37, the end of the first portion 36 is located closer to the laminate 10 side than the end of the second portion 37.

[0077] In the example of FIG. 9, at the overlapping portion P, the first portion 36 and the second portion 37 extend in a direction intersecting the stacking direction D. However, the first portion 36 and the second portion 37 may be extended along the stacking direction D by being bent, for example, inward in the stacking direction D.

[0078] Also, in the above example, the case where the sheet member 30 has three layers of the first insulating layer 42, the metal layer 41, and the second insulating layer 43 has been described. However, from the viewpoint of suppressing short circuit and moisture intrusion, the sheet member 30 may have at least the metal layer 41 and the first insulating layer 42. Alternatively, the sheet member 30 may have four or more layers including the metal layer 41 and the first insulating layer 42.

[0079] Furthermore, in the above example, the sheet member 30 is provided along each of the four side portions of the laminate 10 when viewed in the stacking direction D. However, in the power storage modules 1 to 1C, the sheet member 30 only needs to be provided along at least one of the four side portions of the laminate 10 when viewed in the stacking direction D. That is, the sheet member 30 is not limited to the case where it is composed of four portions 30A to 30D that cover the four side surfaces of the outer side surface 10s of the square tube shape. From the viewpoint of suppressing short circuit and moisture intrusion, it only needs to have a portion that covers at least one side surface.

Explanation of Signs

[0080] 1, 1A, 1B, 1C... Power storage module, 10... Laminate, 10s... Outer side surface, 11... Bipolar electrode, 12... Negative terminal electrode, 13... Positive terminal electrode, 15... Current collector, 15c... Peripheral portion, 15d... Exposed portion, 16... Positive electrode active material layer, 17... Negative electrode active material layer, 20... Sealing portion, 21... First resin layer, 21a... First surface, 21b... Second surface, 22... Second resin layer, 22s... End face, 23... Third resin layer, 30... Sheet member, 31, 33, 36... First portion, 32, 34, 37... Second portion, 35... Third portion, 41... Metal layer, 42... First insulating layer, 43... Second insulating layer, 45... Insulating tape, A1... First region, A2... Second region, A3... Third region, G... Gap, P... Overlapping portion.

Claims

1. A laminate having an outer surface, A sheet member provided in close contact with the laminate so as to cover the outer surface in a cross-section along the lamination direction of the laminate, Comprising, The sheet member includes a metal layer and a first insulating layer laminated on the metal layer and disposed on the outer surface side of the metal layer, The laminate has a plurality of electrodes laminated along the lamination direction, a sealing portion, and an electrolyte, Each of the electrodes includes a current collector, The electrolyte is accommodated in a space between the current collectors adjacent to each other in the lamination direction, The sealing portion is a frame-shaped member for sealing the electrolyte in the space, The electrodes include a plurality of bipolar electrodes, a positive terminal electrode, and a negative terminal electrode, Each of the bipolar electrodes has a current collector, a positive electrode active material layer provided on one surface of the current collector, and a negative electrode active material layer provided on the other surface of the current collector, and the positive electrode active material layer and the negative electrode active material layer are laminated so as to face each other, The positive terminal electrode has the current collector and the positive electrode active material layer provided on the one surface of the current collector, and is laminated on the bipolar electrode at one end in the lamination direction of the laminate, The negative terminal electrode has the current collector and the negative electrode active material layer provided on the other surface of the current collector, and is laminated on the bipolar electrode at the other end in the lamination direction of the laminate, The sealing portion is, A plurality of first resin layers in a frame shape provided at the peripheral edges of each of the plurality of current collectors, A second resin layer that seals the space by welding the ends of each of the plurality of first resin layers on the side opposite to the space, Having, The outer surface is, The end face on the side opposite to the space in the second resin layer, A first surface that is the outer surface in the lamination direction of the first resin layer provided on the current collector of the positive terminal electrode, A second surface that is the outer surface in the lamination direction of the first resin layer provided on the current collector of the negative terminal electrode, Including, The outer surfaces in the lamination direction of the current collectors of the positive terminal electrode and the negative terminal electrode each include an exposed portion exposed to the outside from the sealing portion, The sheet member extends from the first surface through the end face to the second surface, and is divided into a plurality of mutually insulated portions in the cross-section along the lamination direction, A power storage module.

2. Of the plurality of portions of the divided sheet member, adjacent portions thereof include overlapping portions that overlap each other. The power storage module according to claim 1.

3. Of the plurality of portions of the divided sheet member, adjacent portions thereof are spaced apart such that a gap is formed between the respective ends thereof. An insulating member is disposed in the gap. The power storage module according to claim 1.

4. The sealing portion includes a plurality of frame-shaped third resin layers. The third resin layer is disposed so as to be interposed between the first resin layers adjacent to each other in the stacking direction. The second resin layer seals the space by welding the ends on the opposite sides of the spaces of the plurality of first resin layers and the plurality of third resin layers, respectively. The power storage module according to claim 1.

5. The sheet member includes a second insulating layer laminated on the metal layer on the side opposite to the first insulating layer. In the overlapping portion, electrical insulation is formed by overlapping the first insulating layer of one portion and the second insulating layer of another portion adjacent to the one portion. The power storage module according to claim 2.

6. In the overlapping portion, one portion that is relatively vertically above is overlapped on another portion that is relatively vertically below. The power storage module according to claim 2.

7. An insulating tape adhered to the sheet member so as to cover the overlapping portion is provided. The power storage module according to claim 2.

8. The plurality of portions include a first portion extending from the first surface to the end surface and a second portion extending from the second surface to the end surface. The first portion and the second portion overlap each other on the end surface. The power storage module according to claim 2.

9. The plurality of portions are a first portion disposed on the first surface, a second portion disposed on the second surface, a third portion extending from the end surface so as to overlap the first portion and the second portion, and include In the overlapping portions of the first portion and the second portion with the third portion, the third portion is overlapped outside the first portion and the second portion. The power storage module according to claim 2.

10. The plurality of portions are a first portion disposed on the first surface, a second portion disposed on the second surface, a third portion extending from the end face so as to overlap each of the first portion and the second portion; comprising; at the overlapping portion of the first portion and the third portion, the end of the third portion is closer to the laminate side than the end of the first portion within the cross section along the lamination direction, and the end of the first portion and the end of the third portion are in contact with each other; at the overlapping portion of the second portion and the third portion, the end of the third portion is closer to the laminate side than the end of the second portion within the cross section along the lamination direction, and the end of the second portion and the end of the third portion are in contact with each other; The power storage module according to claim 2.

11. The plurality of portions are; a first portion extending from one of the first surface and the second surface so as to cover the end face; a second portion extending from the other of the first surface and the second surface toward the first portion; comprising; The power storage module according to claim 1.

12. The current collector is; a first region where the positive electrode active material layer and the negative electrode active material layer are formed as viewed from the lamination direction; a second region located outside the first region as viewed from the lamination direction; a third region located outside the second region as viewed from the lamination direction and where the first resin layer is formed; comprising; The sheet member extends so as to reach the vicinity of the boundary between the third region and the second region as viewed from the lamination direction. The power storage module according to claim 1.

13. The laminate is square in shape having four side portions as viewed from the lamination direction; The sheet member is provided along at least one of the four side portions when viewed from the lamination direction. The power storage module according to claim 1.

14. The sheet member is divided into a plurality of fourth portions as viewed from the lamination direction; As viewed from the lamination direction, the ends of adjacent fourth portions overlap each other to form an overlapping portion. The power storage module according to any one of claims 1 to 13.

Images