power storage module

Abstract

An electricity storage module (1) includes: an electrode laminate (10); a closure body (20) for enclosing the electrode laminate (10); and a separator (14) interposed between adjacent electrodes. A spacer (22) of the closure body (20) includes: a main body portion (22M) formed in a frame shape along an outer shape of a current collector (15) of the electrode; and a communication hole forming portion (22F) forming a communication hole (30) by being absent from an outer edge (22t) to an inner edge (22e) of the spacer (22). The separator (14) extends in a manner of being interposed between adjacent positive active material layers (16) and negative active material layers (17) and being sandwiched between adjacent seal members (21) in the closure body (20) and the spacer (22). The separator (14) includes a base material (14a) and a ceramic layer (14b) formed on the base material (14a) at least in a portion overlapping the communication hole forming portion (22F).

Description

Technical Field

[0001] This disclosure relates to energy storage modules. Background Technology

[0002] Patent Document 1 describes a bipolar battery. This bipolar battery comprises: a bipolar electrode having a positive active material layer disposed on one side of a current collector and a negative active material layer disposed on the other side of the current collector; a gel electrolyte sandwiched between the positive and negative active material layers; and a sealing layer surrounding and disposed between the current collectors of a single cell composed of the positive active material layer, the negative active material layer, and the gel electrolyte. The bipolar battery has a structure in which multiple single cells are stacked together. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2004-158343 Summary of the Invention The problem the invention aims to solve

[0004] In the bipolar battery-like energy storage module described in Patent Document 1, a separator is sometimes placed between adjacent positive and negative active material layers. Specifically, by extending the separator from between the positive and negative active material layers to the sealing layer, the internal space formed between adjacent current collectors can be divided into a positive-side space on the positive active material layer side and a negative-side space on the negative active material layer side. In this case, for example, if a foreign object exists in the negative-side space and penetrates the separator, a short circuit may occur between uncoated portions of the current collectors adjacent to the separator where no active material layer has been formed. Furthermore, while various substances can be imagined as foreign objects, as an example, it is conceivable that metallic foreign objects dissolved in the electrolyte in the positive-side space may redeposit in the negative-side space, resulting in precipitates.

[0005] The purpose of this invention is to provide an energy storage module that can suppress short circuits. Solution for solving the problem

[0006] The energy storage module of the present invention comprises: an electrode stack including a plurality of electrodes stacked along a first direction; a sealing body disposed on the electrode stack for sealing the electrode stack; and spacers between adjacent electrodes along the first direction. Each electrode has: a current collector including a first surface intersecting the first direction and a second surface opposite to the first surface; a first active material layer disposed on the first surface; and a second active material layer disposed on the second surface, having a polarity different from the first active material layer. The sealing body has: a plurality of sealing members stacked along the first direction, formed in a frame shape along the outline of the current collector when viewed from the first direction, and joined to the first and second surfaces at the periphery of the current collector; and a plurality of spacers between adjacent sealing members along the first direction, which, together with the adjacent sealing members along the first direction, enclose the current collectors adjacent along the first direction. An internal space for containing electrolyte is formed; and a plurality of connecting holes connect each of the internal spaces to the outside. When viewed from the first direction, the outer edge of the second active material layer is located outside the outer edge of the first active material layer. The spacer includes: a main body portion formed in a frame shape along the shape of the current collector when viewed from the first direction; and a connecting hole forming portion formed by a gap from the outer edge of the spacer to the inner edge when viewed from the first direction. When viewed from the first direction, the inner edge of the main body portion is located inside the outer edge of the second active material layer. The spacer extends between the first and second active material layers adjacent along the first direction and sandwiched between the seal and the spacer adjacent along the first direction. The spacer includes a substrate and a ceramic layer formed on the substrate, at least in the portion overlapping the connecting hole forming portion when viewed from the first direction.

[0007] In this energy storage module, an enclosed body is provided in the electrode stack to form an internal space for containing electrolyte between the current collectors of adjacent electrodes. Furthermore, a spacer is located between the first and second active material layers of adjacent electrodes. More specifically, the spacer extends between the first and second active material layers and is sandwiched between a seal forming the enclosed body and a spacer adjacent to the seal. Thus, the spacer divides the internal space into a first space on the side of the first active material layer and a second space on the side of the second active material layer.

[0008] On the other hand, in this energy storage module, the spacer includes a frame-shaped main body that, when viewed from the stacking direction (first direction), is formed along the outline of the current collector. Regarding the main body, its inner edge is located inside the outer edge of the second active material layer, which extends outward from the first active material layer. In other words, the main body of the spacer extends from between adjacent seals in a manner overlapping the second active material layer. Therefore, in the uncoated portions of the current collector adjacent to the spacer where no active material layer is formed, the main body of the spacer is also interposed in the stacking direction, in addition to the spacer, thereby suppressing short circuits, for example, caused by foreign objects present in the second space within the internal space.

[0009] Here, the spacer includes not only the main body but also a connecting hole forming portion, which, when viewed from the stacking direction, forms a connecting hole extending from the outer edge to the inner edge of the spacer. This connecting hole connects the internal space to the outside, allowing for the introduction and export of fluids such as electrolytes or inspection gases relative to the internal space. By providing such a connecting hole forming portion to the spacer, areas without an active material layer may appear in the uncoated portions of current collectors adjacent to each other, separated by a spacer. Therefore, in these areas, the spacer is less effective in preventing short circuits between uncoated portions caused by foreign matter.

[0010] In this energy storage module, the spacer, at least in the portion overlapping the connecting hole forming portion (i.e., the missing portion of the spacer) when viewed from the stacking direction, includes a substrate and a ceramic layer formed on the substrate, ensuring rigidity compared to the case where only the substrate is present. Therefore, even in the aforementioned region where there is no spacer in between, foreign objects penetrating the spacer are suppressed, resulting in the suppression of short circuits between uncoated portions of adjacent current collectors. Thus, according to this energy storage module, short circuits can be suppressed.

[0011] Here, the spacer is sandwiched between a seal disposed on the current collector and a spacer stacked on the seal. Therefore, for example, when the seal and the spacer are fused together, heat input to the seal is conducted through the current collector and is difficult to transfer to the spacer. On the other hand, heat input to the spacer is easily transferred to the spacer, which may cause the spacer to deteriorate.

[0012] In this respect, in the energy storage module of the present invention, a ceramic layer can be formed on the spacer side of the seal and spacer sandwiching the separator in the substrate. In this case, a ceramic layer is formed on the spacer side of the seal and spacer sandwiching the separator in the substrate. Therefore, heat input to the spacer is difficult to transfer to the substrate, thereby suppressing the deterioration of the separator. Furthermore, in this case, for example, when the spacer expands and contracts due to heat generated during charging and discharging, even if the separator and spacer slide, wear (or damage) of the separator can be suppressed by the ceramic layer.

[0013] In the energy storage module of the present invention, the thickness of the ceramic layer can be 2 μm or more. In this case, short circuits can be suppressed more reliably.

[0014] In the energy storage module of the present invention, the electrolyte may contain LiFSI as an electrolyte salt. Thus, in an electrolyte containing LiFSI (lithium bisfluorosulfonylimide), metallic foreign matter is readily dissolved in the positive electrode side space, which is between the positive and negative electrode sides, and therefore precipitates are easily formed in the negative electrode side space. Consequently, short-circuit suppression becomes more effective as described above.

[0015] In the energy storage module of the present invention, a reinforcing portion may be provided in the current collector of the outermost electrode, i.e., the terminal electrode, located in the first direction. When viewed from the first direction, the reinforcing portion is provided in the portion between the outer edge of at least the first active material layer in the current collector of the terminal electrode and the inner edge of the seal. In this case, the reinforcing portion is formed in at least the uncoated portion of the current collector of the terminal electrode, thereby ensuring rigidity. As a result, for example, during decompression of the internal space, the deflection of the current collector of the terminal electrode inward in the stacking direction, thus preventing narrowing of the distance between it and other current collectors (i.e., ensuring the distance between current collectors). Consequently, short circuits between current collectors can be more reliably suppressed, and the flow path of fluid in the internal space can be reliably ensured. Invention Effects

[0016] According to the present invention, an energy storage module capable of suppressing short circuits can be provided. Attached Figure Description

[0017] Figure 1 This is a schematic cross-sectional view of the energy storage module involved in this embodiment. Figure 2 yes Figure 1 A schematic top view of the energy storage module shown. Figure 3 It is Figure 1 A schematic cross-sectional view of a portion of the energy storage module shown is enlarged. Figure 4 yes Figure 1 , Figure 3 The top view of the spacer shown. Figure 5 It is a schematic cross-sectional view showing an enlarged portion of the energy storage module. Figure 6 This is a schematic cross-sectional view of the energy storage module involved in the variation example. Detailed Implementation

[0018] Hereinafter, an embodiment of an energy storage module will be described with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are labeled with the same reference numerals, and repeated descriptions are sometimes omitted. Furthermore, in the drawings, an orthogonal coordinate system is sometimes shown, defining the X direction, the Y direction orthogonal to the X direction, and the Z direction orthogonal to both the X and Y directions.

[0019] Figure 1 This is a schematic cross-sectional view of the energy storage module involved in this embodiment. Figure 2 yes Figure 1 A schematic top view of the energy storage module shown. Figure 1 and Figure 2 The energy storage module 1 shown is, for example, an energy storage module used in batteries of various vehicles such as forklifts, hybrid vehicles, and electric vehicles. Energy storage module 1 is, for example, a nickel-metal hydride secondary battery or a lithium-ion secondary battery. Energy storage module 1 can also be a double-layer capacitor or an all-solid-state battery. Here, the case where energy storage module 1 is a lithium-ion secondary battery is illustrated.

[0020] The energy storage module 1 includes an electrode stack 10 and a enclosure 20. The electrode stack 10 includes multiple electrodes stacked along the Z direction (first direction). The multiple electrodes include multiple bipolar electrodes 11, a positive terminal electrode 12, and a negative terminal electrode 13. A separator 14 is located between the electrodes that are adjacent to each other along the Z direction.

[0021] The bipolar electrode 11 has a current collector 15, a positive active material layer 16 (first active material layer), and a negative active material layer 17 (second active material layer). The current collector 15 is, for example, in the shape of a rectangular sheet. The current collector 15 includes a first surface 15a and a second surface 15b. The first surface 15a is a surface intersecting the Z direction, and the second surface 15b is a surface intersecting the Z direction and opposite to the first surface 15a. That is, the first surface 15a is the side facing the Z direction (in... Figure 1 The middle surface (in the direction from the positive terminal electrode 12 to the negative terminal electrode 13) of the current collector 15 is the other surface (in the direction of the Z direction). Figure 1 The middle part is the surface from the negative terminal electrode 13 to the positive terminal electrode 12.

[0022] A positive electrode active material layer 16 is disposed on the first surface 15a of the current collector 15. A negative electrode active material layer 17 is disposed on the second surface 15b of the current collector 15. Multiple bipolar electrodes 11 are stacked such that the positive electrode active material layer 16 of one bipolar electrode 11 is opposite to the negative electrode active material layer 17 of another bipolar electrode 11. Grooves may also be formed in the positive electrode active material layer 16 and the negative electrode active material layer 17.

[0023] The positive electrode active material layer 16 and the negative electrode active material layer 17 are rectangular in shape when viewed from the Z direction. The negative electrode active material layer 17 is larger than the positive electrode active material layer 16 when viewed from the Z direction. That is, when viewed from above from the Z direction, the entire formation area of ​​the positive electrode active material layer 16 is located within the formation area of ​​the negative electrode active material layer 17. In other words, when viewed from the Z direction, the outer edge 17e of the negative electrode active material layer 17 is located further outward than the outer edge 16e of the positive electrode active material layer 16.

[0024] The positive terminal electrode 12 (terminal electrode) has a current collector 15 and a positive active material layer 16 disposed on a first surface 15a of the current collector 15. The positive terminal electrode 12 does not have a positive active material layer 16 and a negative active material layer 17 on a second surface 15b of the current collector 15. That is, no active material layer is disposed on the second surface 15b of the current collector 15 of the positive terminal electrode 12. The positive terminal electrode 12 is located at the outermost part of the electrode stack 10 in the Z direction and is stacked on top of the bipolar electrode 11. The positive terminal electrode 12 is stacked on the bipolar electrode 11 with its positive active material layer 16 facing the negative active material layer 17 of the bipolar electrode 11.

[0025] The negative terminal electrode 13 (terminal electrode) has a current collector 15 and a negative active material layer 17 disposed on the second surface 15b of the current collector 15. The negative terminal electrode 13 does not have a positive active material layer 16 or a negative active material layer 17 on the first surface 15a of the current collector 15. That is, no active material layer is disposed on the first surface 15a of the current collector 15 of the negative terminal electrode 13. The negative terminal electrode 13 is located at the outermost position of the electrode stack 10 in the opposite direction (negative Z direction) to the Z direction, and is stacked on the bipolar electrode 11. The negative terminal electrode 13 is stacked on the bipolar electrode 11 with its negative active material layer 17 facing the positive active material layer 16 of the bipolar electrode 11.

[0026] Furthermore, in this embodiment, although the current collectors of the bipolar electrode 11, the positive terminal electrode 12, and the negative terminal electrode 13 are labeled with the same reference numeral 15, the current collectors of the bipolar electrode 11, the positive terminal electrode 12, and the negative terminal electrode 13 may be the same or different from each other. Additionally, the surface of the positive terminal electrode 12 without the positive active material layer 16 and the surface of the negative terminal electrode 13 without the negative active material layer 17 are in contact with, for example, tabs used for current extraction, and therefore are not in contact with the electrolyte.

[0027] The separator 14 is disposed between adjacent bipolar electrodes 11, between the positive terminal electrode 12 and the bipolar electrode 11, and between the negative terminal electrode 13 and the bipolar electrode 11. The separator 14 is located between the positive electrode active material layer 16 and the negative electrode active material layer 17, extending in a manner reaching the enclosure 20. The separator 14 is a component that allows charge carriers such as lithium ions to pass through, preventing short circuits caused by contact between adjacent electrodes by isolating the positive electrode active material layer 16 and the negative electrode active material layer 17.

[0028] The current collector 15 is a chemically inert conductor used to continuously allow current to flow through the positive electrode active material layer 16 and the negative electrode active material layer 17 during the discharge or charging of the lithium-ion secondary battery. The material of the current collector 15 may be, for example, a metallic material, a conductive resin material, or a conductive inorganic material. Examples of conductive resin materials include conductive polymers or resins in which conductive fillers are added to non-conductive polymers as needed. The current collector 15 may also have multiple layers. In this case, each layer of the current collector 15 may also contain the aforementioned metallic material and / or conductive resin material.

[0029] A cladding layer may also be formed on the surface of the current collector 15. This cladding layer can be formed, for example, by known methods such as plating or spraying. The current collector 15 may be in the form of a plate, a foil (e.g., a metal foil), a film, or a mesh. Examples of metal foils include aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil. The current collector 15 may also be an alloy foil of the aforementioned metals or a foil formed by integrating multiple metal foils. When the current collector 15 is in the form of a foil, its thickness may be, for example, 1 μm to 200 μm. In this embodiment, the current collector 15 is a foil formed by integrating aluminum foil and copper foil, or a foil formed by copper vapor deposition on aluminum foil.

[0030] The positive electrode active material layer 16 contains a positive electrode active material capable of absorbing and releasing charge carriers such as lithium ions. Examples of positive electrode active materials include lithium composite metal oxides with a layered rock salt structure, metal oxides with a spinel structure, and polyanionic compounds. The positive electrode active material can be any active material that can be used in lithium-ion secondary batteries. The positive electrode active material layer 16 may also contain multiple positive electrode active materials. In this embodiment, the positive electrode active material layer 16 contains olivine-type lithium iron phosphate (LiFePO4) as a composite oxide.

[0031] The negative electrode active material layer 17 contains a negative electrode active material capable of absorbing and releasing charge carriers such as lithium ions. The negative electrode active material can be any of an element, an alloy, or a compound. Examples of negative electrode active materials include lithium (Li), carbon, and metal compounds. The negative electrode active material can also be an element or its compound that can alloy with lithium. Examples of carbon include natural graphite, artificial graphite, hard carbon (difficult-to-graphitize carbon), or soft carbon (easily-graphitize carbon). Examples of artificial graphite include highly oriented graphite and mesophase carbon microspheres. Examples of elements capable of alloying with lithium include silicon or tin. In this embodiment, the negative electrode active material layer 17 contains graphite as a carbon-based material.

[0032] The positive electrode active material layer 16 and the negative electrode active material layer 17 (hereinafter sometimes simply referred to as "active material layers") may each contain, as needed, conductive additives to improve electrical conductivity, binders, electrolytes (polymer matrix, ion-conducting polymer, electrolyte solution, etc.), and electrolyte support salts (lithium salts) to improve ion conductivity. The conductive additives are added to improve the conductivity of each electrode (bipolar electrode 11, positive terminal electrode 12, negative terminal electrode 13). Examples of conductive additives include acetylene black, carbon nanotubes (CNTs), carbon black, or graphite.

[0033] Examples of adhesives include fluorinated resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber; thermoplastic resins such as polypropylene and polyethylene; imide resins such as polyimide and polyamide-imide; resins containing alkoxysilyl groups; 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 crosslinks; and starch-acrylic acid graft polymers. These adhesives can be used alone or in combination. Solvents for these adhesives may include, for example, water and N-methyl-2-pyrrolidone (NMP).

[0034] The separator 14 can be, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains the electrolyte. Examples of materials for the separator 14 include polypropylene, polyethylene, polyolefins, and polyester. The separator 14 can have a single-layer or multi-layer structure. A multi-layer structure can include, for example, an adhesive layer or a ceramic layer as a heat-resistant layer. The separator 14 may also be impregnated with an electrolyte. The electrolyte impregnated with the separator 14 is a liquid electrolyte (electrolyte) containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent.

[0035] As the electrolyte salt, known lithium salts such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, and LiN(CF3SO2)2 can be used. That is, the electrolyte can contain LiFSI (lithium bisfluorosulfonylimide) as the electrolyte salt. An example of such an electrolyte is shown below.

[0036] Electrolyte Lithium salt: LiFSI1.6 (mol / L) Non-aqueous solvent: EC (ethylene carbonate) 15 (volume%) MP (methyl propionate) 85 (volume%)

[0037] In addition, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, and ethers can be used as non-aqueous solvents. Furthermore, two or more of these known solvent materials can be used in combination.

[0038] The enclosure 20, viewed from the Z-direction, is disposed on the electrode stack 10 in a manner that surrounds the electrode stack 10, and is formed into a rectangular cylindrical shape at the periphery of the electrode stack 10. The enclosure 20 can be joined (fused) to each of the first surface 15a and the second surface 15b of the current collector 15 at their respective periphery 15c. The enclosure 20 is used to form an internal space S between adjacent current collectors 15 in the Z-direction and to enclose each of these internal spaces S (i.e., the electrode stack 10). An electrolyte (e.g., electrolyte solution) is contained in each internal space S. The enclosure 20 can prevent the electrolyte contained in the internal space S from flowing out to the outside. In addition, the enclosure 20 can prevent the intrusion of air or moisture from the outside of the electrode stack 10 into the internal space S.

[0039] The enclosure 20 includes an insulating material. Examples of materials for the enclosure 20 include various resin materials such as polypropylene, polyethylene, polystyrene, ABS resin, acid-modified polypropylene, acid-modified polyethylene, and acrylonitrile styrene resin.

[0040] The enclosure 20 includes a plurality of resin seals 21 and a plurality of resin spacers 22. Seals 21 are disposed on each current collector 15. Therefore, the plurality of seals 21 are stacked along the Z-direction. The seals 21, viewed from the Z-direction, are frame-shaped (here, rectangular) along the outline of the current collector 15 and are disposed on the peripheral portion 15c of the current collector 15. The seals 21 are disposed such that they extend from the first surface 15a of the current collector 15, through the end face, to the second surface 15b, thus covering the peripheral portion 15c.

[0041] That is, the seal 21 has an inner portion 21a that overlaps with the current collector 15 when viewed from the Z direction, and an outer portion 21b located outside the end edge of the current collector 15, respectively, on the first surface 15a and the second surface 15b of the current collector 15. A pair of adjacent portions of the seal 21 that sandwich the current collector 15 are interconnected in the outer portion 21b. The inner portion 21a of the seal 21 can be fused to both the first surface 15a and the second surface 15b of the current collector 15. In this embodiment, the seal 21 is fused to both the first surface 15a and the second surface 15b of the current collector 15.

[0042] Furthermore, in this embodiment, although the sealing elements provided in the current collector 15 of the bipolar electrode 11, the current collector 15 of the positive terminal electrode 12, and the current collector 15 of the negative terminal electrode 13 are each marked with the same reference numeral as sealing element 21, the sealing elements provided in the current collector 15 of the bipolar electrode 11, the current collector 15 of the positive terminal electrode 12, and the current collector 15 of the negative terminal electrode 13 may be the same as each other or different from each other.

[0043] The spacer 22 is arranged between each of the adjacent seals 21 in the Z direction. Thus, the spacer 22, together with the pair of adjacent seals 21 in the Z direction, maintains a spacing between adjacent current collectors 15 in the Z direction. The internal space S is defined by the pair of adjacent current collectors 15 in the Z direction, the spacer 22, and the pair of seals 21 adjacent to the spacer 22. In this way, each of the multiple spacers 22, together with the seals 21 adjacent along the Z direction, forms an internal space S between adjacent current collectors 15 in the Z direction.

[0044] The spacer 22, viewed from the Z-direction, is a frame-like (here, a rectangular frame-like) shape following the outline of the current collector 15, and is disposed on the periphery 15c of the current collector 15. That is, the spacer 22 has an inner portion 22a that overlaps with the current collector 15 when viewed from the Z-direction, and an outer portion 22b located outside the outer edge 15e of the current collector 15. The spacer 22 does not overlap with the current collector 15 in the outer portion 22b when viewed from the Z-direction. Both the inner portion 22a and the outer portion 22b are frame-like (here, rectangular frame-like) when viewed from the Z-direction.

[0045] The spacer 14 extends between the adjacent positive electrode active material layer 16 and negative electrode active material layer 17 along the Z direction, and is sandwiched between the adjacent seal 21 and spacer 22 along the Z direction. The outer end of the spacer 14 can be held between the seal 21 and spacer 22. In this embodiment, the spacer 14 is fixed by welding to the seal 21 at its outer end, and no welding or other joint is formed between the spacer 14 and the spacer 22.

[0046] A portion of the outer portion 21b of a plurality of seals 21 located outside the outer edge 15e of the current collector 15 (i.e., the end of the outer portion 21b) is fused together with a portion of the outer portion 22b of a plurality of spacers 22 located outside the outer edge 15e of the current collector 15 (i.e., the end of the outer portion 22b), forming a welded portion 23. That is, the enclosure 20 includes a welded portion 23 formed by fusing together the outer portions 21b of the plurality of seals 21 and the outer portions 22b of the plurality of spacers 22. The welded portion 23, viewed from the Z direction, is frame-shaped in a manner surrounding the electrode stack 10, forming the outer periphery of the enclosure 20. Therefore, the outer surface of the welded portion 23 forms the outer surface of the enclosure 20. That is, in this embodiment, the enclosure 20 has four outer surfaces extending along the Z direction. The spacers 22 may not be fused to the seals 21 at least in the inner portions 21a adjacent to the seals 21 in the Z direction. The corner of the welded portion 23 can be chamfered by performing chamfering processes such as light chamfering, C-chamfering, and R-chamfering.

[0047] Furthermore, conductive members (not shown) are stacked on the portions of the current collector 15 of the positive terminal electrode 12 and the second surface 15b of the current collector 15 of the negative terminal electrode 13 that are exposed from the enclosure 20 (i.e., the portions where the seal 21 is not provided when viewed from the Z direction). The conductive members are electrically connected to the current collector 15 of the positive terminal electrode 12 and the current collector 15 of the negative terminal electrode 13, respectively. The conductive members are positioned between adjacent energy storage modules 1 and function as terminals for extracting current from the energy storage modules 1. The conductive members can be used to electrically connect multiple energy storage modules 1. Multiple energy storage modules 1 can be connected in series via the conductive members.

[0048] Alternatively, the conductive member can also be used as a member for applying a constraint load to the electrode stack 10. That is, when a constraint member (not shown) constrains the energy storage module 1 in the Z direction is provided, a constraint load can be applied to the electrode stack 10 via the conductive member. Furthermore, a cooling flow path can also be formed in the conductive member. By allowing a cooling medium to flow through the cooling flow path formed in the conductive member, the energy storage module 1 can be cooled. Alternatively, members (not shown) integrally or separately formed with the conductive member can be arranged on both sides of the enclosure 20 in the Z direction, and a constraint load can be applied to the enclosure 20 via these members.

[0049] Figure 3 It is Figure 1 A schematic cross-sectional view of a portion of the energy storage module shown is enlarged. Figure 1 and Figure 3 In this configuration, the separator 14 is disposed between the negative electrode active material layer 17 side of the spacer 22 and the sealing member 21 opposite to that side.

[0050] like Figures 1-3 As shown, viewed from the Z direction, the inner edge 22e of the spacer 22 (i.e., a portion of the inner portion 22a) is located between the outer edge 17e of the negative electrode active material layer 17 and the outer edge 16e of the positive electrode active material layer 16. Therefore, the spacer 22 includes a repeating portion 22r that, viewed from the Z direction, overlaps with the negative electrode active material layer 17, and a non-repeating portion 22p that, viewed from the Z direction, does not overlap with the seal 21 and the negative electrode active material layer 17.

[0051] The outermost spacer 22 in the Z direction (here, the one closest to the positive terminal electrode 12) can be held between a pair of adjacent negative electrode active material layers 17 in the repeating portion 22r, separated by an insulating material 14. More specifically, the repeating portion 22r of the outermost spacer 22 in the Z direction can contact the first surface 15a of the current collector 15 and the insulating material 14 opposite to the first surface 15a. In this case, the outermost spacer 22 in the Z direction can be joined (e.g., fused) to the first surface 15a of the current collector 15 in the repeating portion 22r.

[0052] In this embodiment, the spacers 22 other than the outermost spacer 22 in the Z direction (the middle spacers 22) are configured such that they do not contact the current collector 15 of the adjacent bipolar electrode 11 in the repeating portion 22r. That is, the thickness Ts of the spacers 22 in the Z direction is thinner than the thickness Tp of the positive electrode active material layer 16 in the Z direction. In other words, the internal space S is located between the middle spacer 22 and the first surface 15a of the current collector 15 of the adjacent bipolar electrode. In this embodiment, the thickness Ts of the spacers 22 in the repeating portion 22r can be equal to the thickness of the portion of the spacers 22 that repeats with the seal 21 when viewed from the Z direction.

[0053] Additionally, the negative electrode active material layer 17 includes: a rectangular first portion 171 that overlaps with the positive electrode active material layer 16 when viewed from the Z direction; and a frame-shaped (here, a rectangular frame-shaped) second portion 172 that, when viewed from the Z direction, is located outside the outer edge 16e of the positive electrode active material layer 16 and includes the outer edge 17e of the negative electrode active material layer 17. The thickness Tn of the negative electrode active material layer 17 in the Z direction can be constant or different in the first portion 171 and the second portion 172. In this embodiment, the thickness T1 of the first portion 171 in the Z direction and the thickness T2 of the second portion 172 in the Z direction are consistent with each other, but it is also possible to embed the positive electrode active material layer 16 into the negative electrode active material layer 17 so that the thickness T2 of the second portion 172 is larger than the thickness T1 of the first portion 171.

[0054] Furthermore, the current collector 15 includes: a first region 151 (an uncoated portion where no active material layer is formed), which, viewed from the Z direction, does not overlap with the negative electrode active material layer 17 and the sealant 21; and a second region 152, which, viewed from the Z direction, overlaps with the negative electrode active material layer 17 but does not overlap with the positive electrode active material layer 16. The first region 151 is the region between the outer edge 17e of the negative electrode active material layer 17 and the inner edge 21e of the sealant 21. That is, the first region 151, viewed from the Z direction, coincides with the non-repeating portion 22p of the spacer 22.

[0055] The second region 152 is the region between the outer edge 16e of the positive electrode active material layer 16 and the outer edge 17e of the negative electrode active material layer 17. In this embodiment, the width W1 of the first region 151 viewed from the Z direction is narrower than the width W2 of the second region 152 viewed from the Z direction. Furthermore, by including the repeating portion 22r in the spacer 22 as described above, the spacer 22 is arranged between adjacent current collectors 15 in the Z direction in the first region 151.

[0056] Furthermore, the electrode stack 10 includes: a first stack portion 101 in which the negative electrode active material layer 17 and the positive electrode active material layer 16 overlap when viewed from the Z direction; and a second stack portion 102, which includes a portion in which the negative electrode active material layer 17 overlaps with the spacer 22 (repetition portion 22r) when viewed from the Z direction. The second stack portion 102, when viewed from the Z direction, coincides with the region that combines the first region 151 and the second region 152. The closure body 20 includes a first closure portion 201 in which the seal 21 overlaps with the spacer 22 when viewed from the Z direction. The first closure portion 201, when viewed from the Z direction, does not repeat the repetition portion 22r or the non-repetition portion 22p of the spacer 22. In this embodiment, the thickness in the Z direction decreases in the order of the first stack portion 101, the second stack portion 102, and the first closure portion 201. That is, the thickness of the second layer 102 in the Z direction is thinner than the thickness of the first layer 101 in the Z direction, and the thickness of the first closing portion 201 in the Z direction is thinner than the thickness of the second layer 102 in the Z direction.

[0057] Figure 4 yes Figure 1 , Figure 3 The top view of the spacer shown. Figure 5 This is a schematic cross-sectional view showing an enlarged portion of the energy storage module. For example... Figure 1 , Figure 2 , Figure 4 , Figure 5 As shown, the enclosure 20 has multiple communication holes 30 that connect each of the multiple internal spaces S to the outside. Each internal space S is connected to the outside via a communication hole 30. Thus, the communication holes 30 can be used for the introduction and export of fluid relative to the internal spaces S. That is, the communication holes 30 can be used when injecting electrolyte into the internal spaces S, or when introducing or exporting inspection gas relative to the internal spaces S. For example, after the electrolyte injection or the introduction and export of inspection gas is completed, the communication holes 30 can be sealed by a membrane containing a metal layer via another resin component formed on the outside of the enclosure 20.

[0058] In this embodiment, the connecting hole 30 is formed by cutting away a portion of the spacer 22. That is, the spacer 22 includes: a main body portion 22M, which, when viewed in the Z direction, is formed in a frame shape (rectangular frame shape) along the outline of the current collector 15; and a connecting hole forming portion 22F, which, when viewed in the Z direction, forms the connecting hole 30 by being cut away from the outer edge 22t of the spacer 22 to the inner edge 22e. When viewed in the Z direction, a plurality of connecting holes 30 are formed at multiple locations on one side of the enclosure 20. Therefore, the connecting hole forming portions 22F are also similarly formed at multiple locations on one side of the enclosure 20. That is, the connecting hole forming portions 22F of adjacent spacers 22 along the Z direction are formed at different locations when viewed in the Z direction.

[0059] As described above, the spacer 14 extends between the positive electrode active material layer 16 and the negative electrode active material layer 17 adjacent along the Z direction, and is sandwiched between the seal 21 and the spacer 22 adjacent along the Z direction. Thus, the spacer 14 divides the internal space S between the current collectors 15 adjacent along the Z direction into a positive electrode side space containing the positive electrode active material layer 16 and a negative electrode side space containing the negative electrode active material layer 17. Furthermore, in the portion of the electrode stack 10 that overlaps with the main body 22M of the spacer 22 when viewed from the Z direction, in addition to the spacer 14, the spacer 22 (main body 22M) is also located between the current collectors 15 adjacent along the Z direction.

[0060] On the other hand, in the portion of the electrode stack 10 that overlaps with the connecting hole forming portion 22F of the spacer 22 when viewed from the Z direction, by partially removing the spacer 22, only the separator 14 is located between adjacent current collectors 15 in the Z direction. Therefore, for example, if a foreign object is present in the negative electrode side space and the foreign object penetrates the separator 14, a short circuit may occur between adjacent current collectors 15 via the separator 14. Furthermore, although various substances can be imagined as foreign objects, as an example, it is conceivable that a metallic foreign object dissolved in the electrolyte in the positive electrode side space may redeposit in the negative electrode side space, resulting in precipitates.

[0061] In this embodiment, the spacer 14, at least in the portion overlapping the connecting hole forming portion 22F when viewed from the Z direction, includes a substrate 14a and a ceramic layer 14b formed on the substrate 14a. The substrate 14a is equivalent to a conventional spacer made of the various materials described above, and has a thickness of approximately 10 μm. The ceramic layer 14b has a thickness of at least 2 μm (for example, approximately 4 μm). In this embodiment, the ceramic layer 14b is disposed on the entire surface of the substrate 14a. Furthermore, the ceramic layer 14b is formed on the spacer 22 side of the seal 21 and spacer 22 that sandwich the spacer 14 in the substrate 14a.

[0062] As explained above, in the energy storage module 1 of this embodiment, by providing a sealing body 20 on the electrode stack 10, an internal space S for containing electrolyte is formed between the current collectors 15 of adjacent electrodes. Furthermore, a spacer 14 is located between the positive electrode active material layer 16 and the negative electrode active material layer 17 of adjacent electrodes. More specifically, the spacer extends between the positive electrode active material layer 16 and the negative electrode active material layer 17, and is sandwiched between the sealing member 21 constituting the sealing body 20 and the spacer 22 adjacent to the sealing member 21. Thus, the spacer 14 can divide the internal space S into a positive electrode side space (first space) on the positive electrode active material layer 16 side and a negative electrode side space (second space) on the negative electrode active material layer 17 side.

[0063] On the other hand, in the energy storage module 1 according to this embodiment, the spacer 22 includes a frame-shaped main body 22M formed along the outline of the current collector 15 when viewed from the stacking direction (Z direction). Regarding the main body 22M, its inner edge is located inside the outer edge 17e of the negative electrode active material layer 17, which extends outward from the positive electrode active material layer 16. In other words, the main body 22M of the spacer 22 extends from between adjacent seals 21 in a manner overlapping with the negative electrode active material layer 17. Therefore, in the uncoated portion (first region 151) of the current collector 15 adjacent to the separator 14 where no active material layer is formed, the main body 22M of the spacer 22 is also spaced in the middle in the Z direction, in addition to the separator 14, thereby suppressing short circuits, for example, caused by foreign objects present in the negative electrode side space of the internal space S.

[0064] Here, in addition to the main body 22M, the spacer 22 also includes a connecting hole forming portion 22F, which, when viewed from the Z direction, forms a connecting hole 30 by extending from the outer edge 22t of the spacer 22 to the inner edge 22e. By providing such a connecting hole forming portion 22F to the spacer 22, in the uncoated portion (first region 151) of the current collector 15 adjacent to the separator 14 where no active material layer has been formed, a region may be generated where the spacer 22 is not in between. Therefore, in this region, the spacer 22 is less effective in suppressing short circuits between uncoated portions caused by foreign matter.

[0065] In this embodiment, the energy storage module 1 includes a substrate 14a and a ceramic layer 14b formed on the substrate 14a, at least in the portion overlapping the connecting hole forming portion 22F (i.e., the missing portion of the spacer) when viewed from the Z direction. This ensures rigidity compared to the case where only the substrate 14a exists (i.e., the conventional spacer). Therefore, even in the aforementioned region where the spacer 22 is not in between, the penetration of foreign objects through the spacer 14 is suppressed, resulting in the suppression of short circuits between uncoated portions of adjacent current collectors 15. As described above, the energy storage module 1 according to this embodiment can suppress short circuits.

[0066] Here, the spacer 14 is sandwiched between the seal 21 disposed on the current collector 15 and the spacer 22 stacked on the seal 21. Therefore, for example, when the seal 21 and the spacer 22 are fused together (for example, when forming the fusion portion 23), the heat input to the seal 21 is lost prematurely through conduction via the current collector 15 and is difficult to transfer to the spacer 14. On the other hand, the heat input to the spacer 22 is easily transferred to the spacer 14, which may become a cause of deterioration of the spacer 14.

[0067] In this embodiment, in the separator 14 of the energy storage module 1, a ceramic layer 14b is formed on the spacer 22 side of the seal 21 and spacer 22 sandwiching the separator 14 in the substrate 14a. Therefore, heat input to the spacer 22 is difficult to transfer to the substrate 14a, thus suppressing the deterioration of the separator 14. Furthermore, according to this configuration, for example, when the spacer 22 expands and contracts due to heat generated during charging and discharging, even if the separator 14 and the spacer 22 slide, wear (or damage) of the separator 14 can be suppressed by the ceramic layer 14b.

[0068] Furthermore, in the energy storage module 1 according to this embodiment, the thickness of the ceramic layer 14b is 2 μm or more. Therefore, short circuits can be suppressed more reliably.

[0069] Furthermore, in the energy storage module 1 according to this embodiment, the electrolyte may contain LiFSI as the electrolyte salt. In this way, in an electrolyte containing LiFSI (lithium bisfluorosulfonylimide), metallic foreign matter is easily dissolved in the positive electrode side space, which is between the positive and negative electrode sides, thus easily producing precipitates in the negative electrode side space. Therefore, suppressing short circuits becomes more effective as described above.

[0070] The above embodiments illustrate one aspect of the present invention. Therefore, the present invention is not limited to the above embodiments and can be modified in any way. Next, modified examples will be described.

[0071] Figure 6 This is a schematic cross-sectional view of the energy storage module involved in the variation example. For example... Figure 6 As shown, the energy storage module 1 has a reinforcing portion 40 on the current collector 15 of the outermost electrode of the positive terminal electrode 12, which is located in the Z direction of the electrode stack 10 (e.g., by bonding or welding). The reinforcing portion 40 is formed into a plate shape, for example, from a metal such as aluminum. The reinforcing portion 40 is provided on the second surface 15b of the current collector 15 of the positive terminal electrode 12 facing outward in the Z direction. When viewed from the Z direction, the reinforcing portion 40 is provided in the portion between the outer edge 16e of at least the positive active material layer 16 of the current collector 15 of the positive terminal electrode 12 and the inner edge 21e of the sealing member 21.

[0072] However, the reinforcing part 40 may also be provided on the entire surface of the second surface 15b of the current collector 15 of the positive terminal electrode 12 (excluding the part covered by the seal 21), and may also be configured as a rectangular frame when viewed from the Z direction. In addition, the reinforcing part 40 may also be provided on the outermost surface 15a of the current collector 15 of the other electrode, namely the negative terminal electrode 13, which is located at the outermost part of the electrode stack 10 in the Z direction.

[0073] According to this modified example, a reinforcing portion 40 is formed at least in the uncoated portion of the current collector 15 of the positive terminal electrode 12 to ensure rigidity. As a result, for example, when the internal space S is depressurized, the inward bending of the current collector 15 of the positive terminal electrode 12 in the Z direction and the narrowing of the distance between it and other current collectors 15 are suppressed (i.e., the distance between current collectors 15 is ensured). As a result, short circuits between current collectors 15 are more reliably suppressed, and the flow path of fluids in the internal space S (i.e., the escape of gas or electrolyte) is reliably ensured.

[0074] Furthermore, in the illustrated example, a reinforcing portion 40 is shown as a component separately formed from the current collector 15. However, the reinforcing portion 40 may also be integrally formed with the current collector 15. In this case, the reinforcing portion 40 is integrally formed by making the thickness of the current collector 15 of the positive terminal electrode 12 (and the negative terminal electrode 13) thicker than the thickness of the current collector 15 of the other electrodes (i.e., the bipolar electrode 11).

[0075] In the above embodiment, an example was described where the width W1 of the first region 151 of the current collector 15, viewed from the Z direction, is narrower than the width W2 of the second region 152 of the current collector 15, viewed from the Z direction. However, the width W1 of the first region 151, viewed from the Z direction, may also be the same as the width W2 of the second region 152, and the width W1 of the first region 151, viewed from the Z direction, may also be wider than the width W2 of the second region 152, viewed from the Z direction.

[0076] Furthermore, in the above embodiment, an example was described in which the outermost spacer 22 in the Z direction contacts the current collector 15 of the positive terminal electrode 12 in the repeating section 22r, but the spacer 22 may also not contact the current collector 15 of the positive terminal electrode 12 in the repeating section 22r.

[0077] The following are notes on the above implementation methods.

[0078] An energy storage module is, [1] "an energy storage module comprising: an electrode stack comprising a plurality of electrodes stacked along a first direction; a closure disposed thereon for sealing the electrode stack; and a spacer disposed between adjacent electrodes along the first direction, the electrodes having: a current collector comprising a first surface intersecting the first direction and a second surface opposite to the first surface; a first active material layer disposed thereon on the first surface; and a second active material layer disposed thereon on the second surface having a polarity different from the first active material layer, the closure comprising: a plurality of seals stacked along the first direction, formed in a frame shape along the outline of the current collector when viewed from the first direction, and joined to the first surface and the second surface at the periphery of the current collector; a plurality of spacers disposed between adjacent seals along the first direction, and together with the adjacent seals along the first direction, in the current collector adjacent along the first direction An internal space for containing electrolyte is formed between the current collectors; and a plurality of connecting holes connect each of the internal spaces to the outside. When viewed from the first direction, the outer edge of the second active material layer is located outside the outer edge of the first active material layer. The spacer includes: a main body portion formed in a frame shape along the outline of the current collector when viewed from the first direction; and a connecting hole forming portion formed by a gap from the outer edge of the spacer to the inner edge when viewed from the first direction. When viewed from the first direction, the inner edge of the main body portion is located inside the outer edge of the second active material layer. The spacer extends between the first active material layer and the second active material layer adjacent along the first direction and sandwiched between the seal and the spacer adjacent along the first direction. The spacer includes a substrate and a ceramic layer formed on the substrate, at least in the portion overlapping the connecting hole forming portion when viewed from the first direction.

[0079] The energy storage module may also be, [2] "the energy storage module according to [1] above, wherein the ceramic layer is formed on the spacer side of the seal and the spacer that sandwich the separator in the substrate."

[0080] The energy storage module may also be, [3] "the energy storage module according to [1] or [2] above, wherein the thickness of the ceramic layer is 2 μm or more.

[0081] The energy storage module may also be, [4] "the energy storage module according to any one of [1] to [3] above, wherein the electrolyte contains LiFSI as an electrolyte salt."

[0082] The energy storage module may also be, [5] "the energy storage module according to any one of [1] to [4] above, wherein the current collector of the outermost electrode, i.e. the terminal electrode, located in the first direction, is provided with a reinforcing portion, which, when viewed from the first direction, is provided in the portion between the outer edge of at least the first active material layer in the current collector of the terminal electrode and the inner edge of the seal." Explanation of reference numerals in the attached figures

[0083] 1. Energy Storage Module 10 Electrode Laminates 11. Bipolar electrode (electrode) 12 Positive terminal electrode (terminal electrode) 13 Negative terminal electrode (terminal electrode) 14. Isolation materials 14a Substrate 14b Ceramic layer 15 Current collectors 15a First Surface 15b Surface 2 16. Positive electrode active material layer (first active material layer) 16e outer edge 17. Negative electrode active material layer (second active material layer) 17e Outer edge 20 Closed body 21 Seals 22 spacers 22t outer edge 22e Inner edge 22M Main Body 22F Connecting Hole Forming Section 30 connecting holes 40 Reinforced Department S represents the interior space.

Claims

1. A power storage module, characterized in that, have: An electrode stack comprising a plurality of electrodes stacked along a first direction; A sealing body, disposed on the electrode stack, for sealing the electrode stack; and A spacer, which is located between adjacent electrodes along the first direction, The electrode has: A current collector comprising a first surface intersecting the first direction and a second surface on the opposite side of the first surface; A first active material layer, which is disposed on the first surface; and A second active material layer, disposed on the second surface, has a different polarity than the first active material layer. The enclosed body has: Multiple seals are stacked along the first direction and formed in a frame shape along the outline of the current collector when viewed from the first direction, and are joined to the first surface and the second surface at the periphery of the current collector; Multiple spacers are located between adjacent seals along the first direction, forming an internal space for receiving electrolyte together with the adjacent seals along the first direction between adjacent current collectors along the first direction; as well as Multiple connecting holes connect each of the aforementioned internal spaces to the outside. Viewed from the first direction, the outer edge of the second active material layer is located further outward than the outer edge of the first active material layer. The spacer comprises: The main body, viewed from the first direction, is formed in a frame shape along the outline of the current collector; and The connecting hole forming portion, when viewed from the first direction, is formed by a gap extending from the outer edge to the inner edge of the spacer. When viewed from the first direction, the inner edge of the main body is located further inward than the outer edge of the second active material layer. The spacer extends in a manner that is situated between the first active material layer and the second active material layer adjacent along the first direction, and sandwiched between the seal and the spacer adjacent along the first direction. The spacer includes a substrate and a ceramic layer formed on the substrate, at least in the portion that overlaps with the connecting hole forming portion when viewed from the first direction.

2. The energy storage module according to claim 1, wherein, The ceramic layer is formed on the spacer side of the seal and the spacer that sandwich the separator in the substrate.

3. The energy storage module according to claim 1, wherein, The thickness of the ceramic layer is 2 μm or more.

4. The energy storage module according to claim 1, wherein, The electrolyte contains LiFSI as an electrolyte salt.

5. The energy storage module according to any one of claims 1 to 4, wherein, A reinforcing portion is provided on the current collector of the outermost electrode, i.e., the terminal electrode, located in the first direction. The reinforcing portion, when viewed from the first direction, is disposed in the portion between the outer edge of at least the first active material layer in the current collector of the terminal electrode and the inner edge of the seal.

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