Power storage module

Abstract

Disclosed is a power storage module which comprises: an electrode stack that comprises a plurality of electrodes stacked in the Z-axis direction; a sealing body 20 that seals the internal space of the electrode stack; and a detection line 60 that is electrically connected to an electrode. The sealing body 20 has: a main sealing body 40 provided on a peripheral edge part of the electrode stack; and an injection molded body 50 provided in a detection line part of the main sealing body 40, the detection line part overlapping with the detection line 60. The injection molded body 50 comprises a first overhang part 52 provided on an end surface on one side of the main sealing body 40 in the Z-axis direction. The detection line 60 comprises a connection part 61 that overlaps with a collector 15 of the electrode when viewed from the Z-axis direction and is electrically connected to the collector 15. The first overhang part 52 overlaps with the connection part 61 when viewed from the Z-axis direction.

Description

Energy storage module

[0001] The present invention relates to an electricity storage module.

[0002] A known energy storage module includes a stack including a plurality of electrodes stacked along a stacking direction, a sealing body that seals the internal space of the stack, and a detection wire that is connected to a current collector of the electrode and extends to the outside of the sealing body (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2008-117626

[0004] In the energy storage module described above, the current collector may be deformed due to an increase in internal pressure of the stack, and in such a case, the detection wire connected to the current collector may be peeled off from the current collector.

[0005] An object of the present invention is to provide an electricity storage module that can suppress peeling of a detection line.

[0006] The energy storage module of the present invention comprises a laminate having a plurality of electrodes, each including a current collector and an active material layer, stacked along a stacking direction, a sealing body provided on the peripheral portion of the laminate, and a detection line electrically connected to the electrode, wherein the sealing body has a sealing body provided on the peripheral portion of the laminate so as to surround the laminate when viewed from the stacking direction and seals the internal space of the laminate to which the detection line is connected, and an injection-molded body provided on a detection line portion of the sealing body that overlaps with the detection line when viewed from the stacking direction, wherein the injection-molded body includes a first overhang portion provided on an end face on one side of the sealing body in the stacking direction, and the detection line includes a connection portion that overlaps with the current collector of the electrode when viewed from the stacking direction and is electrically connected to the current collector, and the first overhang portion overlaps with the connection portion when viewed from the stacking direction.

[0007] In this energy storage module, when viewed from the stacking direction, the first overhang overlaps the connection portion of the detection wire connected to the current collector. This restrains the current collector and the connection portion in the stacking direction by the first overhang. Therefore, even if the internal pressure of the stack increases, deformation of the current collector is suppressed, and as a result, peeling of the connection portion from the current collector is suppressed. Therefore, this energy storage module can suppress peeling of the detection wire.

[0008] When viewed from the stacking direction, the width of the first overhang portion in the extension direction of the detection line may be larger than the width of the connection portion in the extension direction of the detection line.

[0009] The sealing body has a liquid inlet portion that is spaced apart from the detection line portion when viewed from the stacking direction and includes a liquid inlet that is connected to the internal space of the stack, and the first overhang portion includes a first portion that overlaps with the detection line portion when viewed from the stacking direction and a second portion that overlaps with the liquid inlet portion when viewed from the stacking direction, and when viewed from the stacking direction, the width of the first portion in the extension direction of the detection line may be greater than the width of the second portion in the extension direction of the detection line.

[0010] The first part of the first overhang portion includes a thick portion and a thin portion that is thinner than the thick portion, and the thick portion overlaps the connection portion when viewed from the stacking direction, and the thin portion does not have to overlap the connection portion when viewed from the stacking direction.

[0011] The detection line may be electrically connected to a current collector of a first terminal electrode located at one end of the stack in the stacking direction.

[0012] The sealing body may include a first sealing member provided on the peripheral edge of the current collector of the first terminal electrode, and the first overhang portion may be located on one side of the first sealing member in the stacking direction and welded to the first sealing member.

[0013] When viewed from the stacking direction, the width of the first overhang portion in the extension direction of the detection line may be smaller than the width of the first seal member in the extension direction of the detection line.

[0014] The injection molded body further includes a side wall portion provided on a side surface of the sealing body and connected to the first overhang portion, and a second overhang portion provided on the other end surface of the sealing body in the stacking direction and connected to the side wall portion, and the second overhang portion may overlap with the connection portion of the detection line when viewed from the stacking direction.

[0015] The sealing body has a liquid inlet port portion that is spaced apart from the detection line portion when viewed from the stacking direction and includes a liquid inlet hole that is connected to the internal space of the stack, and the second overhang portion includes a third portion that overlaps with the detection line portion when viewed from the stacking direction and a fourth portion that overlaps with the liquid inlet port portion when viewed from the stacking direction, and when viewed from the stacking direction, the width of the third portion in the extension direction of the detection line may be greater than the width of the fourth portion in the extension direction of the detection line.

[0016] The sealing body includes a second sealing member provided on the peripheral portion of the current collector of the second terminal electrode located at the other end of the stack in the stacking direction, and the second overhang portion may be located on the other side of the second sealing member in the stacking direction and welded to the second sealing member.

[0017] According to the present invention, it is possible to provide an electricity storage module that can suppress peeling of detection lines.

[0018] FIG. 1 is a plan view of an energy storage module according to an embodiment. FIG. 2 is a side view of the energy storage module shown in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a partially enlarged view of FIG. 1. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 4. FIG. 6 is a plan view of an energy storage module according to a first modified example. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6. FIG. 8 is a plan view of an energy storage module according to a second modified example. FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8.

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated explanations will be omitted.

[0020] The power storage module 1 shown in Fig. 1 is mounted on, for example, a forklift, a hybrid vehicle, or an electric vehicle. The power storage module 1 is, for example, a nickel-metal hydride secondary battery or a lithium-ion secondary battery. The power storage module 1 may also be, for example, an electric double layer capacitor. In this embodiment, the power storage module 1 is a lithium-ion secondary battery.

[0021] 1 and 2 , the energy storage module 1 includes an electrode stack 10, a sealing body 20, a sealing member 30, and a plurality of detection lines 60. The electrode stack 10 includes a plurality of electrodes stacked along the Z-axis direction (stacking direction). The electrode stack 10 has, for example, a rectangular parallelepiped shape.

[0022] The sealing body 20 is provided on the periphery of the electrode stack 10. The sealing body 20 includes a sealing body 40 and an injection-molded body 50. The sealing body 40 is provided on the periphery of the electrode stack 10 so as to surround the electrode stack 10 when viewed from the Z-axis direction. The sealing body 40 seals the side surfaces of the electrode stack 10. The sealing body 40 has, for example, a rectangular cylindrical shape. The sealing body 40 seals the internal space S of the electrode stack 10 to which the detection lines 60 are connected. The sealing body 40 has electrical insulation properties. The sealing body 40 includes a liquid inlet portion 40a including a plurality of liquid inlet holes 20a (described later) and a detection line portion 40b overlapping with the plurality of detection lines 60 when viewed from the Z-axis direction. The liquid inlet portion 40a and the detection line portion 40b are aligned along the X-axis direction. When viewed from the Z-axis direction, the plurality of liquid inlet holes 20a are spaced apart from the detection line portion 40b, and the plurality of detection lines 60 are spaced apart from the liquid inlet hole portion 40a.

[0023] The injection molded body 50 is provided in the liquid inlet portion 40a and the detection line portion 40b. The width of the injection molded body 50 in the X-axis direction is smaller than the width of the sealing body 40 in the X-axis direction. Both ends of the injection molded body 50 in the X-axis direction are located more inward than both ends of the sealing body 40 in the X-axis direction. The injection molded body 50 includes a side wall portion 51, a first overhang portion 52, a second overhang portion 53, a frame portion 54, and a thin-walled portion 55.

[0024] The side wall portion 51 is provided on the side surface 40c of the seal body 40. The side wall portion 51 is provided on both the side surfaces of the liquid injection hole portion 40a and the detection line portion 40b. The side wall portion 51 has, for example, a rectangular plate shape. The first overhang portion 52 is located on one side of the seal body 40 in the Z-axis direction. The first overhang portion 52 is located on one end surface (one end surface) of the seal body 40 in the Z-axis direction. The first overhang portion 52 has, for example, a rectangular plate shape. The second overhang portion 53 is located on the other side of the seal body 40 in the Z-axis direction. The second overhang portion 53 is located on the other end surface (the other end surface) of the seal body 40 in the Z-axis direction. The second overhang portion 53 has, for example, a rectangular plate shape. Each of the first overhang portion 52 and the second overhang portion 53 is connected to the side wall portion 51.

[0025] The injection-molded body 50 includes a plurality of frame portions 54. The frame portions 54 protrude from the side surfaces of the side wall portions 51. When viewed from the Y-axis direction, the frame portions 54 surround the liquid injection holes 20a lined up in the Z-axis direction. The thin-walled portions 55 are provided on the side surfaces of the side wall portions 51 on both sides of the side wall portions 51 in the X-axis direction. The thin-walled portions 55 extend along the Z-axis direction. The thin-walled portions 55 reach both ends of the side wall portions 51 in the Z-axis direction. The thickness of the thin-walled portions 55 is smaller than the thickness of the side wall portions 51. The side wall portions 51, the first overhang portions 52, the second overhang portions 53, the frame portions 54, and the thin-walled portions 55 are each a partial region of the injection-molded body 50 integrated with the same material. The injection-molded body 50 is formed by injection molding.

[0026] The seal body 40 includes a plurality of liquid injection holes 20a. The liquid injection holes 20a are in communication with the internal space S (see FIG. 3 ) of the electrode stack 10. The liquid injection holes 20a function as paths for injecting the electrolyte into the internal space S. The seal body 40 has a plurality of liquid injection hole rows. The plurality of liquid injection hole rows are aligned in the Z-axis direction. Each liquid injection hole row includes a plurality of liquid injection holes 20a aligned in the X-axis direction. Each liquid injection hole row includes, for example, ten liquid injection holes 20a. When viewed from the Y-axis direction, in each liquid injection hole row, the plurality of liquid injection holes 20a are aligned diagonally with respect to the X-axis direction. In each liquid injection hole row, the liquid injection holes 20a are spaced apart from each other in the X-axis direction.

[0027] The sealing member 30 has, for example, a plate shape. When viewed from the X-axis direction, the sealing member 30 overlaps with the multiple frame portions 54. The sealing member 30 is, for example, a laminate sheet or the like. The sealing member 30 includes, for example, a metal layer and a resin layer. The material of the metal layer is, for example, aluminum. The sealing member 30 is welded to the tips of the multiple frame portions 54. This seals the multiple liquid injection holes 20a. Note that the sealing member 30 is not shown in FIG. 2.

[0028] The multiple detection lines 60 are located adjacent to the multiple frame portions 54 when viewed from the Y-axis direction. The detection lines 60 are used to detect the battery state of the energy storage module 1. In this embodiment, the voltage between adjacent electrodes of the energy storage module 1 is detected by an external device via the detection lines 60. In other words, the detection lines 60 are, for example, voltage detection lines. The detection lines 60 protrude from the side wall portion 51. Each detection line 60 is electrically connected to a respective electrode of the electrode stack 10.

[0029] The energy storage module 1 has multiple detection line arrays 70. Each detection line array 70 has multiple detection lines 60 aligned in the Z-axis direction. That is, the multiple detection lines 60 constituting one detection line array 70 overlap each other when viewed in the Z-axis direction. The multiple detection line arrays 70 are aligned along the X-axis direction at predetermined intervals. The positions of the detection lines 60 in the Z-axis direction are shifted from one another. In this embodiment, the detection line arrays 70 are positioned closer to the negative electrode terminal electrode 13 (described later) (lower in FIG. 2 ) as they move away from the frame portion 54 in the X-axis direction. When focusing on a pair of adjacent detection line arrays 70 in the X-axis direction, for example, one detection line 60 of one detection line array 70 is positioned closer to the positive electrode terminal electrode 12 (upper in FIG. 2 ) than another detection line 60 of the other detection line array 70 that is positioned on the opposite side of the frame portion 54 from the first detection line array 70. The one detection line 60 is the Nth (N is a natural number) detection line in the one detection line array 70, counted from the positive terminal electrode 12 side, and the other detection line 60 is the Nth (N is a natural number) detection line in the other detection line array 70, counted from the positive terminal electrode 12 side.

[0030] 3, the electrode stack 10 includes a plurality of bipolar electrodes 11, a positive terminal electrode (first terminal electrode) 12, a negative terminal electrode (second terminal electrode) 13, and a plurality of separators 14. The plurality of bipolar electrodes 11, the positive terminal electrode 12, the negative terminal electrode 13, and the plurality of separators 14 are stacked along the Z-axis direction (stacking direction).

[0031] The bipolar electrode 11 includes a current collector 15, a positive electrode active material layer 16, and a negative electrode active material layer 17. When viewed from the Z-axis direction, the current collector 15 has, for example, a rectangular shape. The current collector 15 includes a surface 15a and a surface 15b opposite to the surface 15a.

[0032] The positive electrode active material layer 16 is provided on the surface 15a. When viewed from the Z-axis direction, the positive electrode active material layer 16 has, for example, a rectangular shape. The surface 15a includes an uncoated region where the positive electrode active material layer 16 is not provided. When viewed from the Z-axis direction, the uncoated region surrounds the positive electrode active material layer 16.

[0033] The negative electrode active material layer 17 is provided on the surface 15b. The polarity of the negative electrode active material layer 17 is different from the polarity of the positive electrode active material layer 16. When viewed from the Z-axis direction, the negative electrode active material layer 17 has, for example, a rectangular shape. The surface 15b includes an uncoated region where the negative electrode active material layer 17 is not provided. When viewed from the Z-axis direction, the uncoated region surrounds the negative electrode active material layer 17. When viewed from the Z-axis direction, the area of ​​the negative electrode active material layer 17 is larger than the area of ​​the positive electrode active material layer 16. When viewed from the Z-axis direction, the outer edge of the negative electrode active material layer 17 is located outside the outer edge of the positive electrode active material layer 16.

[0034] The multiple bipolar electrodes 11 are stacked such that the positive electrode active material layer 16 of one bipolar electrode 11 faces the negative electrode active material layer 17 of another bipolar electrode 11. That is, the multiple bipolar electrodes 11 are stacked such that, of adjacent bipolar electrodes 11, the surface 15a of the current collector 15 of one bipolar electrode 11 faces the surface 15b of the current collector 15 of the other bipolar electrode 11.

[0035] The positive terminal electrode 12 is disposed on one side of the multiple bipolar electrodes 11 in the Z-axis direction. That is, the positive terminal electrode 12 is located at one end of the multiple electrodes of the electrode stack 10 in the Z-axis direction. The positive terminal electrode 12 has a current collector 15 and a positive electrode active material layer 16. A surface (first surface) 15a of the current collector 15 of the positive terminal electrode 12 faces the other end of the electrode stack 10 in the Z-axis direction. A surface (second surface) 15b of the current collector 15 of the positive terminal electrode 12 faces the opposite side to the surface 15a. The positive electrode active material layer 16 of the positive terminal electrode 12 is provided on the surface 15a.

[0036] The positive terminal electrode 12 differs from the bipolar electrode 11 mainly in that it does not have a negative electrode active material layer 17. Other configurations of the positive terminal electrode 12 may be the same as those of the bipolar electrode 11. The positive terminal electrode 12 has a positive electrode active material layer 16 facing the negative electrode active material layer 17 of the bipolar electrode 11. That is, the positive terminal electrode 12 is stacked such that a surface 15a of the current collector 15 of the positive terminal electrode 12 faces a surface 15b of the current collector 15 of the bipolar electrode 11 adjacent to the positive terminal electrode 12.

[0037] The negative electrode terminal electrode 13 is disposed on the other side in the Z-axis direction of the multiple bipolar electrodes 11. In other words, the negative electrode terminal electrode 13 is located at the other end in the Z-axis direction of the multiple electrodes of the electrode stack 10. The negative electrode terminal electrode 13 has a current collector 15 and a negative electrode active material layer 17. The negative electrode active material layer 17 of the negative electrode terminal electrode 13 is provided on a surface 15b.

[0038] The negative terminal electrode 13 differs from the bipolar electrode 11 mainly in that it does not have a positive electrode active material layer 16. Other configurations of the negative terminal electrode 13 may be the same as those of the bipolar electrode 11. The negative electrode active material layer 17 of the negative terminal electrode 13 faces the positive electrode active material layer 16 of the bipolar electrode 11. In other words, the negative terminal electrode 13 is stacked such that the surface 15b of the current collector 15 of the negative terminal electrode 13 faces the surface 15a of the current collector 15 of the bipolar electrode 11 adjacent to the negative terminal electrode 13.

[0039] The outer edges of the current collectors 15 of the electrodes 11, 12, and 13 form the side surfaces of the electrode stack 10. Internal spaces S for accommodating an electrolyte are formed between the bipolar electrodes 11, between the bipolar electrodes 11 and the positive terminal electrode 12, and between the bipolar electrodes 11 and the negative terminal electrode 13.

[0040] Separators 14 are disposed between the bipolar electrodes 11, between the bipolar electrodes 11 and the positive terminal electrode 12, and between the bipolar electrodes 11 and the negative terminal electrode 13. The separators 14 are disposed between the opposing positive electrode active material layers 16 and negative electrode active material layers 17. The separators 14 are, for example, sheet-shaped. When viewed from the Z-axis direction, the outer edges of the separator 14 are located outside the outer edges of the positive electrode active material layers 16 and the negative electrode active material layers 17. The separators 14 allow charge carriers such as lithium ions to pass through. The separators 14 separate the adjacent electrodes 11, 12, and 13. This prevents electrical short circuits due to contact between the electrodes 11, 12, and 13. The separators 14 absorb and retain the electrolyte.

[0041] The current collector 15 has the function of maintaining the flow of current in the positive electrode active material layer 16 and the negative electrode active material layer 17 during discharging or charging of the energy storage module 1. The current collector 15 is, for example, a chemically inactive electrical conductor. The material of the current collector 15 is, for example, a metal material, a conductive resin material, a conductive inorganic material, etc. The conductive resin material is, for example, a conductive polymer material, or a non-conductive polymer material to which a conductive filler has been added, etc. When the current collector 15 has multiple layers, the material of each layer may be any of the materials described above. A coating layer may be formed on the surface of the current collector 15. The coating layer may be formed by a known method such as plating or spray coating.

[0042] The current collector 15 has, for example, a plate, foil, sheet, film, or mesh shape. The current collector 15 may be, for example, an aluminum foil, copper foil, nickel foil, titanium foil, or stainless steel foil. The current collector 15 may be an alloy foil or clad foil of the above metals. When the current collector 15 is foil-shaped, the thickness of the current collector 15 is, for example, 1 μm or more and 100 μm or less. The current collector 15 may be a laminate having multiple metal layers. The current collector 15 may be, for example, a laminate in which an aluminum layer and a copper layer are integrated. The current collector 15 may include, for example, an aluminum foil and copper plating formed on one side of the aluminum foil. The current collector 15 may include multiple metal foils bonded together with a conductive adhesive.

[0043] The positive electrode active material layer 16 includes a positive electrode active material capable of absorbing and releasing charge carriers such as lithium ions. The positive electrode active material is, for example, a composite oxide, metallic lithium, or sulfur. The composite oxide includes, for example, at least one of iron, manganese, titanium, nickel, cobalt, and aluminum, and lithium. The composite oxide is, for example, olivine-type lithium iron phosphate (LiFePO ４ ), LiCoO ２ , LiNiMnCoO ２ etc.

[0044] The negative electrode active material layer 17 includes a negative electrode active material capable of absorbing and releasing charge carriers such as lithium ions. Examples of the negative electrode active material include graphite, artificial graphite, highly oriented graphite, mesocarbon microbeads, hard carbon, soft carbon, metal compounds, elements or compounds thereof that can be alloyed with lithium, and boron-doped carbon. Examples of the elements that can be alloyed with lithium include silicon and tin.

[0045] Each of the positive electrode active material layer 16 and the negative electrode active material layer 17 may contain a binder and a conductive additive in addition to the active material. The binder functions to bind the active material or conductive additive together and maintain a conductive network within the electrode. Examples of binders include fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, and fluororubber; thermoplastic resins such as polypropylene and polyethylene; imide resins such as polyimide and polyamideimide; alkoxysilyl group-containing resins; acrylic resins such as polyacrylic acid and polymethacrylic acid; styrene-butadiene rubber; carboxymethyl cellulose; alginates such as sodium alginate and ammonium alginate; water-soluble cellulose ester crosslinked bodies; and starch-acrylic acid graft polymers. These binders may be used alone or in combination. The conductive additive is a conductive material that enhances electrical conductivity. Examples of conductive additives include acetylene black, carbon black, and graphite. Examples of viscosity-adjusting solvents include N-methyl-2-pyrrolidone.

[0046] Formation of the positive electrode active material layer 16 on the surface 15a and the negative electrode active material layer 17 on the surface 15b can be achieved by conventional methods such as roll coating, die coating, dip coating, doctor blade coating, spray coating, and curtain coating. Specifically, an active material, a solvent, and, if necessary, a binder and a conductive additive are mixed to produce a slurry-like active material layer-forming composition, which is then applied to the surface 15a or the surface 15b and dried. Examples of the solvent include N-methyl-2-pyrrolidone, methanol, methyl isobutyl ketone, and water. The dried electrode may be compressed to increase electrode density.

[0047] The electrolyte solution is accommodated in the internal space S. The separator 14 is impregnated with the electrolyte solution. The electrolyte solution is, for example, a liquid containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent. The electrolyte salt of the electrolyte solution is, for example, LiClO ４ , LiAsF ６ , LiPF ６ , LiBF ４ , LiCF ３ SO ３ , LiN(FSO ２ ) ２ , LiN(CF ３ SO ２ ) ２ The non-aqueous solvent is a cyclic carbonate, a cyclic ester, a chain carbonate, a chain ester, an ether, etc. Two or more of these known solvent materials may be used in combination.

[0048] The sealing body 40 has a sealing member 41, a spacer 42, and a welded portion 43. The sealing member 41 has, for example, a rectangular frame shape. The sealing member 41 is provided on the peripheral portion of each current collector 15. The sealing member 41 covers the peripheral portion of each current collector 15. The sealing member 41 is provided on the surface 15a and the surface 15b of each current collector 15. The sealing member 41 surrounds the positive electrode active material layer 16 and the negative electrode active material layer 17 when viewed from the Z-axis direction. The inner edge of the sealing member 41 is spaced from the positive electrode active material layer 16 and the negative electrode active material layer 17. The sealing member 41 is welded to the current collector 15.

[0049] The spacer 42 has, for example, a rectangular frame shape. The spacer 42 is provided between adjacent seal members 41. The spacer 42 is sandwiched between adjacent seal members 41. The inner peripheral portion of the spacer 42 overlaps with the negative electrode active material layer 17 when viewed from the Z-axis direction. The inner peripheral portion of the spacer 42 is located between the surface 15a of the current collector 15 and the negative electrode active material layer 17. The welded portion 43 is integrated by welding the outer edge portions of each seal member 41 and each spacer 42. The welded portion 43 has, for example, a rectangular cylindrical shape.

[0050] The sealing member 41 and the spacer 42 are made of materials such as acid-modified polyethylene (acid-modified PE), acid-modified polypropylene (acid-modified PP), polyethylene, or polypropylene. The sealing member 41 and the spacer 42 are both electrolyte-resistant. The materials of the sealing member 41 and the spacer 42 may be the same or different. In this embodiment, the sealing member 41 is made of, for example, acid-modified polyethylene or acid-modified polypropylene. In this embodiment, the spacer 42 is made of, for example, polyethylene or polypropylene. Acid-modified polyethylene and acid-modified polypropylene are more easily bonded to metal than non-acid-modified polyethylene and non-acid-modified polypropylene. When the current collector 15 is made of metal, the bonding strength of the sealing member 41 to the current collector 15 can be improved by forming the sealing member 41 from acid-modified polyethylene or acid-modified polypropylene.

[0051] The detection wires 60 are electrically connected to the current collectors 15. The detection wires 60 are connected to the surface 15a of the current collectors 15 of the bipolar electrode 11. The detection wires 60 may be connected to the surface 15b of the current collectors 15 of the bipolar electrode 11. The detection wires 60 are connected to the surface 15a of the current collectors 15 of the positive terminal electrode 12. The detection wires 60 are connected to the surface 15b of the current collectors 15 of the negative terminal electrode 13. When viewed from the Z-axis direction, each detection wire 60 is connected to each current collector 15 at a position away from the liquid inlet 40a. The detection wires 60 are made of, for example, metal. The detection wires 60 are, for example, stainless steel foil. The detection wires 60 are connected to the current collectors 15 by welding. The width in the Y-axis direction of a welded region where the detection wires 60 and the current collectors 15 are welded to each other is shorter than the width in the Y-axis direction of an overlapping region where the detection wires 60 and the current collectors 15 overlap each other when viewed from the Z-axis direction. The welding region is spaced apart in the Y-axis direction from the tip 61c of the detection line 60 and the outer edge 15c of the current collector 15. The width of the welding region in the Y-axis direction may be the same as the width of the overlap region in the Y-axis direction.

[0052] Next, the injection-molded body 50 and the detection wire 60 will be described in detail, focusing on the positive terminal electrode 12. Fig. 4 is a partially enlarged view of Fig. 1. Fig. 5 is a cross-sectional view of the positive terminal electrode 12 and a region of the sealing body 20 provided on the periphery of the positive terminal electrode 12.

[0053] As shown in FIGS. 4 and 5 , the seal member (first seal member) 41 provided on the current collector 15 of the positive terminal electrode 12 includes a first seal portion 411 provided on the surface 15a of the current collector 15 and a second seal portion 412 provided on the surface 15b of the current collector 15. The first seal portion 411 includes a surface 41a facing away from the surface 15b of the current collector 15. The second seal portion 412 includes a surface 41b facing away from the surface 15a of the current collector 15. The surface 41a of the first seal portion 411 and the surface 41b of the second seal portion 412 intersect with each other in the Z-axis direction. When viewed from the Z-axis direction, the inner edge 41c of the first seal portion 411 and the inner edge 41d of the second seal portion 412 are aligned with each other. The thickness of each of the first seal portion 411 and the second seal portion 412 is, for example, approximately 100 μm to 200 μm.

[0054] The detection line 60 includes a connection portion 61 and an extension portion 62. The connection portion 61 is a portion of the detection line 60 that overlaps with the current collector 15 when viewed from the Z-axis direction. The connection portion 61 is located inside the outer edge 15c of the current collector 15 when viewed from the Z-axis direction. The connection portion 61 is electrically connected to the surface 15a of the current collector 15 while being located between the first seal portion 411 of the seal member 41 and the current collector 15. The connection portion 61 is in contact with the surface 15a. When viewed from the Z-axis direction, the connection portion 61 has, for example, a rectangular shape. The shape of the connection portion 61 is not limited. When viewed from the Z-axis direction, the connection portion 61 may include, for example, multiple rectangular portions having different widths.

[0055] The extension portion 62 is a portion of the detection line 60 that does not overlap with the current collector 15 when viewed from the Z-axis direction. The extension portion 62 is located outside the outer edge 15c of the current collector 15 when viewed from the Z-axis direction. The extension portion 62 extends along the Y-axis direction when viewed from the Z-axis direction. The extension portion 62 extends to the outside of the sealing body 20, penetrating the sealing body 20. The extension portion 62 penetrates the welded portion 43 of the sealing body 40 and the side wall portion 51 of the injection-molded body 50.

[0056] The first overhang portion 52 is located on one side in the Z-axis direction of the seal member 41 provided on the current collector 15 of the positive terminal electrode 12. The first overhang portion 52 is a portion of the injection-molded body 50 that is located on the opposite side of the seal member 41 with respect to an imaginary plane that includes the surface 41b of the seal member 41. The first overhang portion 52 is welded to the surface 41b of the seal member 41.

[0057] When viewed from the Z-axis direction, the first overhang portion 52 overlaps with each connection portion 61 of each detection line 60. When viewed from the Z-axis direction, the first overhang portion 52 overlaps with the entirety of each connection portion 61. When viewed from the Z-axis direction, the area of ​​the first overhang portion 52 is larger than the area of ​​each connection portion 61. When viewed from the Z-axis direction, the area of ​​the first overhang portion 52 is larger than the total area of ​​the multiple connection portions 61.

[0058] When viewed from the Z-axis direction, the width of the first overhang portion 52 in the Y-axis direction (the extension direction of the detection line 60) is greater than the width of the connection portion 61 in the Y-axis direction. When viewed from the Z-axis direction, the outer edge 52c of the first overhang portion 52 surrounds the multiple connection portions 61. When viewed from the Z-axis direction, each connection portion 61 is located inside the outer edge 52c of the first overhang portion 52.

[0059] When viewed from the Z-axis direction, the width of the first overhang portion 52 in the Y-axis direction is smaller than the width of the seal member 41 in the Y-axis direction. When viewed from the Z-axis direction, the first overhang portion 52 is located outward from the inner edge 41d of the second seal portion 412 of the seal member 41. In other words, when viewed from the Z-axis direction, the first overhang portion 52 is spaced apart from the inner edge 41d of the second seal portion 412. The first overhang portion 52 does not reach the inner edge 41d. The thickness of the first overhang portion 52 is greater than the thickness of the second seal portion 412. The thickness of the first overhang portion 52 is, for example, approximately several tens of millimeters.

[0060] The first overhang portion 52 includes a first portion 521 and a second portion 522. When viewed from the Z-axis direction, the first portion 521 overlaps the detection line portion 40b (see FIGS. 1 and 2). When viewed from the Z-axis direction, the first portion 521 overlaps the multiple detection lines 60. When viewed from the Z-axis direction, the first portion 521 overlaps the portions of the multiple detection lines 60 that are located inside the sealing body 20. When viewed from the Z-axis direction, the first portion 521 overlaps each connection portion 61 of each detection line 60. When viewed from the Z-axis direction, the first portion 521 overlaps the entirety of each connection portion 61. When viewed from the Z-axis direction, the first portion 521 protrudes toward the inside of the sealing body 40 beyond the tip 61c of each connection portion 61. When viewed from the Z-axis direction, the area of ​​the first portion 521 is larger than the area of ​​each connection portion 61. When viewed in the Z-axis direction, the area of ​​the first portion 521 is larger than the total area of ​​the multiple connection portions 61. When viewed in the Z-axis direction, the first portion 521 has, for example, a rectangular shape.

[0061] When viewed from the Z-axis direction, the second portion 522 overlaps with the liquid inlet port 40a (see FIGS. 1 and 2). When viewed from the Z-axis direction, the second portion 522 is adjacent to the first portion 521 in the X-axis direction. The second portion 522 is connected to the first portion 521. When viewed from the Z-axis direction, the second portion 522 does not overlap with the connection portion 61. When viewed from the Z-axis direction, the second portion 522 has, for example, a rectangular shape. Note that in FIG. 4, the boundary between the first portion 521 and the second portion 522 is indicated by a virtual line.

[0062] When viewed from the Z-axis direction, the width W1 of the first portion 521 in the Y-axis direction is larger than the width W2 of the second portion 522 in the Y-axis direction. When viewed from the Z-axis direction, the first portion 521 protrudes more inward of the sealing body 40 than the second portion 522.

[0063] The second overhang portion 53 is symmetrical to the first overhang portion 52 with respect to the XY plane. The second overhang portion 53 has the same configuration as the first overhang portion 52. The second overhang portion 53 is located on the other side in the Z axis direction of the seal member (second seal member) 41 provided on the current collector 15 of the negative terminal electrode 13. The second overhang portion 53 is welded to the surface of the seal member 41.

[0064] When viewed in the Z-axis direction, the outer edge of the second overhang portion 53 coincides with the outer edge of the first overhang portion 52. Similar to the first overhang portion 52, the second overhang portion 53 overlaps with each connection portion 61 of each detection line 60 when viewed in the Z-axis direction. The second overhang portion 53 includes a third portion 531 (see FIG. 2 ) and a fourth portion 532 (see FIG. 2 ). The third portion 531 has the same configuration as the first portion 521 of the first overhang portion 52. Similar to the first portion 521, the third portion 531 overlaps with the detection line portion 40b when viewed in the Z-axis direction. The fourth portion 532 has the same configuration as the second portion 522 of the first overhang portion 52. Similar to the second portion 522, the fourth portion 532 overlaps with the liquid inlet port 40a when viewed in the Z-axis direction. When viewed from the Z-axis direction, the width of the third portion 531 in the Y-axis direction is greater than the width of the fourth portion 532 in the Y-axis direction.

[0065] As described above, in the energy storage module 1, when viewed from the Z-axis direction, the first overhang portion 52 overlaps with the connection portion 61 of the detection line 60 that is connected to the current collector 15. As a result, the current collector 15 and the connection portion 61 are restrained in the Z-axis direction by the first overhang portion 52, and as a result, even if the internal pressure of the electrode stack 10 increases, deformation of the current collector 15 is suppressed, and peeling of the connection portion 61 from the current collector 15 is suppressed. Therefore, the energy storage module 1 can suppress peeling of the detection line 60.

[0066] When viewed from the Z-axis direction, the width of first overhang portion 52 in the Y-axis direction is larger than the width of connection portion 61 in the Y-axis direction. This more reliably restrains current collector 15 and connection portion 61 by first overhang portion 52, thereby more reliably suppressing peeling of connection portion 61 from current collector 15.

[0067] The first overhang portion 52 includes a first portion 521 that overlaps the detection line portion 40b when viewed from the Z-axis direction and a second portion 522 that overlaps the liquid inlet port 40a when viewed from the Z-axis direction. When viewed from the Z-axis direction, the width W1 of the first portion 521 in the Y-axis direction is greater than the width W2 of the second portion 522 in the Y-axis direction. This reliably restrains the current collector 15 and the connection portion 61 by the first portion 521, thereby reliably preventing the connection portion 61 from peeling off from the current collector 15. In other words, the width W2 of the second portion 522 in the Y-axis direction is smaller than the width W1 of the first portion 521 in the Y-axis direction. This makes it possible to prevent the connection portion 61 from peeling off while suppressing thermal shock caused by an increase in the volume of the first overhang portion 52.

[0068] One of the multiple detection wires 60 is electrically connected to the current collector 15 of the positive terminal electrode 12 located at one end of the electrode stack 10 in the Z-axis direction. When the internal pressure of the electrode stack 10 increases, the current collector 15 of the positive terminal electrode 12 tends to deform more easily than, for example, the current collector 15 of the bipolar electrode 11. Therefore, it is extremely important to prevent the detection wire 60 connected to the current collector 15 of the positive terminal electrode 12 from peeling off. In this embodiment, when viewed from the Z-axis direction, the first overhang portion 52 overlaps with the detection wire 60 (connection portion 61) connected to the current collector 15 of the positive terminal electrode 12, thereby preventing the detection wire 60 connected to the current collector 15 of the positive terminal electrode 12 from peeling off.

[0069] The sealing body 40 includes a seal member 41 provided on the periphery of the current collector 15 of the positive terminal electrode 12. The first overhang portion 52 is located on one side of the seal member 41 in the Z-axis direction and is welded to the seal member 41. This more reliably restrains the current collector 15 and the connection portion 61 by the first overhang portion 52, thereby more reliably preventing the connection portion 61 from peeling off from the current collector 15.

[0070] When viewed from the Z-axis direction, the width of the first overhang portion 52 in the Y-axis direction is smaller than the width of the sealing member 41 in the Y-axis direction. This makes it possible to suppress the thermal shock caused by an increase in the volume of the first overhang portion 52 while also suppressing peeling of the connection portion 61.

[0071] The injection-molded article 50 includes a side wall portion 51 and a second overhang portion 53. The second overhang portion 53 overlaps with the connection portion 61 of the detection line 60 when viewed from the Z-axis direction. This restrains the current collector 15 and the connection portion 61 by the first overhang portion 52 and the second overhang portion 53, thereby more reliably suppressing peeling of the connection portion 61 from the current collector 15.

[0072] The second overhang portion 53 includes a third portion 531 that overlaps the detection line portion 40b when viewed from the Z-axis direction and a fourth portion 532 that overlaps the liquid inlet port 40a when viewed from the Z-axis direction. When viewed from the Z-axis direction, the width of the third portion 531 in the Y-axis direction is greater than the width of the fourth portion 532 in the Y-axis direction. This reliably restrains the current collector 15 and the connection portion 61 by the third portion 531, thereby reliably suppressing peeling of the connection portion 61 from the current collector 15. In other words, the width of the fourth portion 532 in the Y-axis direction is smaller than the width of the third portion 531 in the Y-axis direction. This makes it possible to suppress peeling of the connection portion 61 while suppressing thermal shock caused by an increase in the volume of the second overhang portion 53.

[0073] The sealing body 40 includes a seal member 41 provided on the periphery of the current collector 15 of the negative terminal electrode 13 located at the other end of the electrode stack 10 in the Z-axis direction. The second overhang portion 53 is located on the other side of the seal member 41 in the Z-axis direction and is welded to the seal member 41. This more reliably restrains the current collector 15 and the connection portion 61, thereby more reliably preventing the connection portion 61 from peeling off from the current collector 15.

[0074] Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.

[0075] 6 and 7 , the first portion 521 of the first overhang portion 52 may include a thick portion 5211 and a thin portion 5212. The thick portion 5211 overlaps with the multiple connection portions 61 when viewed from the Z-axis direction. The thin portion 5212 is located on the opposite side of the multiple connection portions 61 from the multiple extension portions 62 when viewed from the Z-axis direction. The thin portion 5212 does not overlap with the connection portions 61 when viewed from the Z-axis direction. The thin portion 5212 is thinner than the thick portion 5211. This makes it possible to suppress peeling of the connection portions 61 while suppressing thermal shock caused by an increase in the volume of the first overhang portion 52.

[0076] (Second Modification) As shown in FIGS. 8 and 9 , the width W1 of the first portion 521 of the first overhang portion 52 may be the same as the width W2 of the second portion 522. When viewed from the Z-axis direction, the tip 61c of each connection portion 61 is exposed from the first portion 521 and protrudes further inward into the sealing body 40 than the first portion 521. The width in the Y-axis direction of the welded region where the detection wire 60 and the current collector 15 are welded to each other is the same as the width in the Y-axis direction of the overlapping region where the detection wire 60 and the current collector 15 overlap each other when viewed from the Z-axis direction. That is, the detection wire 60 and the current collector 15 are welded to each other over the entire overlapping region. This prevents the connection portion 61 from peeling off from the current collector 15 even if the tip 61c of the connection portion 61 is exposed from the first portion 521. The width in the Y-axis direction of the welded region may be shorter than the width in the Y-axis direction of the overlapping region.

[0077] The above-described embodiments and modifications may be combined as appropriate.

[0078] The gist of the present disclosure is as follows: [1] to

[10] : [1] An electricity storage module including: a laminate having a plurality of electrodes, each including a current collector and an active material layer, stacked along a stacking direction; a sealing body provided on a peripheral edge of the laminate; and detection lines electrically connected to the electrodes, wherein the sealing body has a sealing body provided on the peripheral edge of the laminate so as to surround the laminate when viewed from the stacking direction and sealing an internal space of the laminate to which the detection lines are connected; and an injection-molded body provided on a detection line portion of the sealing body that overlaps with the detection line when viewed from the stacking direction, wherein the injection-molded body includes a first overhang portion provided on an end surface on one side of the sealing body in the stacking direction, the detection line includes a connection portion that overlaps with the current collector of the electrode when viewed from the stacking direction and is electrically connected to the current collector, and the first overhang portion overlaps the connection portion when viewed from the stacking direction. [2] The energy storage module according to [1] above, wherein, when viewed from the stacking direction, a width of the first overhang portion in the extension direction of the detection line is larger than a width of the connection portion in the extension direction of the detection line. [3] The energy storage module according to [1] above, wherein the sealing body has a liquid inlet portion that is spaced apart from the detection line when viewed from the stacking direction and includes a liquid inlet that is communicated with the internal space of the stack, the first overhang portion includes a first portion that overlaps with the detection line when viewed from the stacking direction and a second portion that overlaps with the liquid inlet portion when viewed from the stacking direction, and when viewed from the stacking direction, a width of the first portion in the extension direction of the detection line is larger than a width of the second portion in the extension direction of the detection line. [4] The energy storage module according to the above [3], wherein the first portion of the first overhanging portion includes a thick portion and a thin portion that is thinner than the thick portion, the thick portion overlapping the connection portion when viewed from the stacking direction, and the thin portion not overlapping the connection portion when viewed from the stacking direction. [5] The energy storage module according to any one of the above [1] to [4], wherein the detection line is electrically connected to the current collector of a first terminal electrode located at an end of one side of the stack in the stacking direction.[6] The energy storage module according to [5] above, wherein the sealing body includes a first seal member provided on a peripheral portion of the current collector of the first termination electrode, the first overhang portion being located on one side of the first seal member in the stacking direction and welded to the first seal member. [7] The energy storage module according to [6] above, wherein, when viewed from the stacking direction, a width of the first overhang portion in the extension direction of the detection line is smaller than a width of the first seal member in the extension direction of the detection line. [8] The energy storage module according to any one of [1] to [7] above, wherein the injection-molded body further includes a side wall portion provided on a side surface of the sealing body and connected to the first overhang portion, and a second overhang portion provided on an end face on the other side of the sealing body in the stacking direction and connected to the side wall portion, the second overhang portion overlapping the connection portion of the detection line when viewed from the stacking direction. [9] The energy storage module according to [8] above, wherein the sealing body has a liquid inlet port portion that is spaced apart from the detection line portion when viewed from the stacking direction and includes a liquid inlet port that is connected to the internal space of the stack, the second overhang portion includes a third portion that overlaps with the detection line portion when viewed from the stacking direction and a fourth portion that overlaps with the liquid inlet port when viewed from the stacking direction, and a width of the third portion in the extension direction of the detection line when viewed from the stacking direction is greater than a width of the fourth portion in the extension direction of the detection line.

[10] The energy storage module according to [8] or [9] above, wherein the sealing body includes a second seal member provided on a peripheral portion of the current collector of a second terminal electrode that is located at an end of the stack on the other side in the stacking direction of the stack, and the second overhang portion is located on the other side of the second seal member in the stacking direction and is welded to the second seal member.

[0079] 1...energy storage module, 10...electrode laminate (laminate), 11...bipolar electrode, 12...positive electrode terminal electrode, 13...negative electrode terminal electrode, 15...current collector, 16...positive electrode active material layer, 17...negative electrode active material layer, 20...sealing body, 20a...liquid injection hole, 40...sealing body, 40a...liquid injection hole portion, 40b...detection line portion, 41...sealing member, 50...injection molded body, 51...side wall portion, 52...first overhang portion, 53...second overhang portion, 60...detection line, 61...connection portion, 521...first portion, 522...second portion, 531...third portion, 532...fourth portion, 5211...thick portion, 5212...thin portion, S...internal space.

Claims

1. An energy storage module comprising: a laminate having a plurality of electrodes, each including a current collector and an active material layer, stacked along a stacking direction; a sealing body provided on the periphery of the laminate; and detection lines electrically connected to the electrodes, wherein the sealing body has a sealing body provided on the periphery of the laminate so as to surround the laminate when viewed from the stacking direction and sealing the internal space of the laminate to which the detection lines are connected; and an injection-molded body provided on a detection line portion of the sealing body that overlaps with the detection line when viewed from the stacking direction, wherein the injection-molded body includes a first overhang portion provided on an end face on one side of the sealing body in the stacking direction, and the detection line includes a connection portion that overlaps with the current collector of the electrode when viewed from the stacking direction and is electrically connected to the current collector, and the first overhang portion overlaps with the connection portion when viewed from the stacking direction.

2. The energy storage module according to claim 1, wherein, when viewed from the stacking direction, the width of the first overhang portion in the extension direction of the detection line is greater than the width of the connection portion in the extension direction of the detection line.

3. The storage module described in claim 1, wherein the sealing body has a liquid inlet portion that is spaced apart from the detection line portion when viewed from the stacking direction and that includes a liquid inlet that is connected to the internal space of the laminate, the first overhang portion includes a first portion that overlaps with the detection line portion when viewed from the stacking direction, and a second portion that overlaps with the liquid inlet portion when viewed from the stacking direction, and the width of the first portion in the extension direction of the detection line when viewed from the stacking direction is greater than the width of the second portion in the extension direction of the detection line.

4. The energy storage module described in claim 3, wherein the first portion of the first overhanging portion includes a thick portion and a thin portion that is thinner than the thick portion, the thick portion overlaps the connection portion when viewed from the stacking direction, and the thin portion does not overlap the connection portion when viewed from the stacking direction.

5. The energy storage module according to claim 1, wherein the detection line is electrically connected to the current collector of a first terminal electrode located at one end of the stack in the stacking direction.

6. The energy storage module described in claim 5, wherein the sealing body includes a first sealing member provided on the peripheral edge of the current collector of the first terminal electrode, and the first overhang portion is located on one side of the first sealing member in the stacking direction and is welded to the first sealing member.

7. The energy storage module according to claim 6, wherein, when viewed from the stacking direction, the width of the first overhang portion in the extension direction of the detection line is smaller than the width of the first sealing member in the extension direction of the detection line.

8. The energy storage module described in claim 1, wherein the injection-molded body further includes a side wall portion provided on a side surface of the sealing body and connected to the first overhang portion, and a second overhang portion provided on the other end surface of the sealing body in the stacking direction and connected to the side wall portion, and the second overhang portion overlaps with the connection portion of the detection line when viewed from the stacking direction.

9. The storage module described in claim 8, wherein the sealing body has a liquid inlet portion that is spaced apart from the detection line portion when viewed from the stacking direction and includes a liquid inlet that is connected to the internal space of the laminate, the second overhang portion includes a third portion that overlaps with the detection line portion when viewed from the stacking direction, and a fourth portion that overlaps with the liquid inlet portion when viewed from the stacking direction, and the width of the third portion in the extension direction of the detection line when viewed from the stacking direction is greater than the width of the fourth portion in the extension direction of the detection line.

10. The energy storage module described in claim 8, wherein the sealing body includes a second sealing member provided on the peripheral edge of the current collector of a second terminal electrode located at the other end of the stack in the stacking direction, and the second overhang portion is located on the other side of the second sealing member in the stacking direction and is welded to the second sealing member.

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