Power storage module

Abstract

A power storage module is provided with: an electrode laminate including a plurality of electrodes having a current collector and a detection line joined to the current collector; and a sealing body that is provided in the electrode laminate so as to surround the electrode laminate and that seals an internal space between adjacent current collectors, the sealing body having: a plurality of resin sealing materials that are welded to each of the plurality of electrodes; a plurality of resin spacers that are disposed between adjacent sealing members and that form the internal space together with the sealing members; and an outer side surface formed by welding the seals and the spacers to each other, each of the plurality of seals being welded to the current collector and a detection line joined to the current collector, the detection line extending from the current collector and being drawn out from the outer side surface in a second direction intersecting the first direction.

Description

Technical Field

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

[0002] Patent document 1 describes a bipolar secondary battery. In this secondary battery, a plurality of bipolar electrodes having a positive electrode layer formed on one surface of a current collector and a negative electrode layer formed on the other surface of the current collector are arranged in series with an electrolyte layer interposed therebetween, thereby forming a battery element in the form of a single cell layer stacked with a stacked structure consisting of a positive electrode layer, an electrolyte layer, and a negative electrode layer. In addition, a sealant is provided on the periphery of the single cell layer to insulate the current collectors. The sealant is provided on an extension portion of the current collector that extends outwardly from the positive electrode layer and the negative electrode layer. A detection element for voltage measurement or temperature detection is provided on the current collector and is in contact with the current collector.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2008-117626 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] When manufacturing a bipolar secondary battery such as that described in Patent Document 1, when a resin seal is welded to a metal current collector, there is a difference between the linear expansion coefficient of the seal and the linear expansion coefficient of the current collector, and therefore, the shrinkage of the seal after welding may cause deformation such as wrinkles on the current collector. In contrast, the thinner the seal, the smaller the effect of the shrinkage of the seal on the current collector, so it is conceivable that the thickness of the seal is preferably as thin as possible.

[0008] On the other hand, when a laminate is formed by stacking electrodes including a current collector and a detection line as a detection element joined to the current collector, the thickness of the detection line is accumulated at the joint of the detection line, and the thickness of the laminate may increase locally. In this case, it can be considered to make the seal thicker to ensure the elastic deformation of the seal, and absorb the increase in the thickness of the detection line through the elastic deformation of the seal. That is, in this case, it can be conceived that it is preferable to make the seal thicker to suppress the local thickness increase of the laminate.

[0009] An object of the present disclosure is to provide a power storage module capable of suppressing deformation of a current collector and suppressing increase in local thickness of a stacked body.

[0010] Solutions for solving problems

[0011] The storage module involved in the present disclosure comprises: an electrode stack, which is composed of a plurality of electrodes stacked along a first direction, including a collector provided with an active material layer and a detection line connected to the collector; and a sealing body, which is arranged on the electrode stack in a manner surrounding the electrode stack and is used to seal the internal space between the collectors adjacent to each other in the first direction, the sealing body comprising: a plurality of sealants made of resin, which are fused to each of the plurality of electrodes; a plurality of spacers made of resin, which are arranged between each of the sealants adjacent to each other in the first direction and form the internal space together with the sealants; and an outer side surface, which is formed by a first end surface of the sealant on the side opposite to the internal space and a second end surface of the spacer on the side opposite to the internal space by fusing the sealant and the spacer to each other, the plurality of sealants are each fused to the collector and the detection line connected to the collector, and the detection line extends from the collector and is led out from the outer side surface along a second direction intersecting the first direction.

[0012] In the power storage module, an electrode stack is formed by stacking electrodes having a current collector and a detection line joined to the current collector along a first direction. A sealing body for sealing the internal space between the current collectors is provided in the electrode stack. The sealing body includes: a sealant, which is joined to the current collector and the detection line; and a spacer, which is arranged between the adjacent sealants in the first direction and forms an internal space together with the sealant. The detection line is led out from the outer side of the sealing body formed by welding the sealant and the spacer. In this way, in the power storage module, while a sealant is provided as a resin member welded to the current collector (and the detection line), a spacer is provided between the sealants as another resin member. Therefore, it is possible to achieve the effect of shrinkage of the sealant on the current collector while making the sealant thinner and ensuring the elastic deformation of the resin member by using the spacer to absorb the increment of the thickness of the detection line. Therefore, in the power storage module, both the deformation of the collector and the increase in the local thickness of the electrode stack can be suppressed.

[0013] In the battery module disclosed herein, the outer side surface may include a protrusion protruding in the second direction in the lead-out portion of the detection line from the outer side surface. When the seal and the spacer are welded to form the outer side surface, heat may escape to the detection line around the lead-out portion of the detection line, causing the seal and the spacer to fail to be fully welded and the sealing performance to be reduced. Therefore, in this case, by providing a protrusion on the outer side surface of the sealing body for the lead-out portion of the detection line, a larger amount of resin can be ensured, so that the seal and the spacer can be more reliably welded to each other around the lead-out portion, thereby improving the sealing performance.

[0014] In the storage battery module involved in the present disclosure, the lead-out portions of a plurality of detection lines may be dispersed in a plurality of positions in the third direction by setting the lead-out portions adjacent in the first direction at different positions in a third direction intersecting the first direction and the second direction, and the protrusion is formed with a width spanning the plurality of positions in the third direction. In this case, by setting the lead-out portions of the detection lines adjacent in the first direction at different positions in the third direction, the isolation of the detection lines in the first direction can be ensured. In addition, at this time, by forming the protrusion in the seal with a width spanning the plurality of positions where the lead-out portions of the detection lines are set, the preparation of the seal becomes easier than in the case of manufacturing a plurality of seals provided with protrusions corresponding to the plurality of positions of the lead-out portions.

[0015] In the power storage module involved in the present disclosure, at least two of the plurality of detection lines may be configured to overlap each other when viewed from the first direction, and the protrusions at the lead-out portions of the detection lines that overlap each other when viewed from the first direction are separated from each other in the first direction. In this case, by forming the concave and convex portions of the lead-out portions of the detection lines on the outer side surface, the creepage distance between adjacent detection lines in the first direction becomes longer, thereby suppressing short circuits between the detection lines.

[0016] In the power storage module involved in the present disclosure, the current collector and the detection wire may be made of different metals, and the thermal conductivity of the metal constituting the detection wire may be lower than the thermal conductivity of the metal constituting the current collector. In this case, the heat generated when the outer side surface is formed by welding the seal and the spacer is suppressed from escaping to the current collector through the detection wire, thereby suppressing poor welding of the seal and the spacer.

[0017] In the power storage module of the present disclosure, the current collector and the detection wire may be made of metal, and the seal may be made of acid-modified resin. In this case, the bonding strength between the seal and the current collector and the detection wire can be ensured, and the sealing performance can be improved.

[0018] In the battery module involved in the present disclosure, the detection line may be embedded in the seal in the portion where the seal and the spacer overlap along the first direction. In this case, in the portion where the seal and the spacer overlap, the detection line is embedded in the seal composed of an acid-modified resin that can be suitably bonded to metal. Therefore, in this portion, even if the spacer is not an acid-modified resin, it can be reliably sealed by fusing with the seal.

[0019] In the battery module involved in the present disclosure, a cutout may be provided at a portion of the detection line sandwiched by the collector and the seal along the first direction. In this case, the detection line can be prevented from falling off by the anchoring effect brought about by the cutout. In particular, since the cutout is provided at a portion of the detection line sandwiched by the collector and the sealant, the anchoring effect is exerted from the time when the sealant is welded to the collector and the detection line, thereby preventing the detection line from falling off.

[0020] Effects of the Invention

[0021] According to the present disclosure, it is possible to provide a power storage module capable of suppressing deformation of a current collector and suppressing increase in local thickness of a stacked body. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic plan view of the power storage module according to the present embodiment.

[0023] Figure 2 It is along Figure 1 Schematic cross-sectional view along line II-II.

[0024] Figure 3 It is a plan view showing the relationship among the current collector, the detection wire, and the sealing member. DETAILED DESCRIPTION

[0025] Hereinafter, a storage module according to an embodiment will be described with reference to the accompanying drawings. In the description of each figure, the same or equivalent elements are marked with the same reference numerals, and repeated descriptions are sometimes omitted. In addition, in each figure, an orthogonal coordinate system consisting of a first axis defining a first direction D1, a second axis defining a second direction D2, and a third axis defining a third direction D3 is sometimes shown.

[0026] Figure 1 It is a schematic plan view of the power storage module according to the present embodiment. Figure 2 It is along Figure 1 Schematic cross-sectional view along line II-II. Figure 1 , Figure 2 The power storage module 1 shown is, for example, a power storage module used in batteries of various vehicles such as forklifts, hybrid vehicles, and electric vehicles. The power storage module 1 is, for example, a secondary battery such as a nickel-hydrogen secondary battery or a lithium-ion secondary battery. The power storage module 1 may also be a double-layer capacitor or an all-solid-state battery. Here, the case where the power storage module 1 is a lithium-ion secondary battery is exemplified.

[0027] The power storage module 1 includes an electrode stack 10 and a sealing body 20. The electrode stack 10 includes a plurality of electrodes stacked along a first direction D1. The plurality of electrodes include a plurality of bipolar electrodes 11, a positive terminal electrode 12, and a negative terminal electrode 13. A separator 14 is interposed between adjacent electrodes.

[0028] The bipolar electrode 11 includes a current collector 15, a positive electrode active material layer 16, and a negative electrode active material layer 17. The current collector 15 is, for example, in the form of a rectangular sheet. The positive electrode active material layer 16 is provided on one surface 15a of the current collector 15. The negative electrode active material layer 17 is provided on the other surface 15b of the current collector 15. The plurality of bipolar electrodes 11 are stacked in such a manner that the positive electrode active material layer 16 of one bipolar electrode 11 faces the negative electrode active material layer 17 of another bipolar electrode 11. Here, one surface 15a of the current collector 15 is a surface facing one side of the first direction D1, and the other surface 15b of the current collector 15 is a surface facing the other side of the first direction D1.

[0029] The positive electrode active material layer 16 and the negative electrode active material layer 17 are rectangular when viewed from the first direction D1. The negative electrode active material layer 17 is slightly larger than the positive electrode active material layer 16 when viewed from the first direction D1. That is, when viewed from above from the first direction D1, the entire formation region of the positive electrode active material layer 16 is located within the formation region of the negative electrode active material layer 17.

[0030] The positive terminal electrode 12 includes a current collector 15 and a positive electrode active material layer 16 provided on one surface 15a of the current collector 15. The positive terminal electrode 12 does not include the positive electrode active material layer 16 and the negative electrode active material layer 17 on the other surface 15b of the current collector 15. That is, no active material layer is provided on the other surface 15b of the current collector 15 of the positive terminal electrode 12. The positive terminal electrode 12 is stacked on the bipolar electrode 11 at one end portion of the electrode stack 10 in the first direction D1. The positive terminal electrode 12 is stacked on the bipolar electrode 11 in such a manner that the positive electrode active material layer 16 thereof faces the negative electrode active material layer 17 of the bipolar electrode 11.

[0031] The negative terminal electrode 13 includes a current collector 15 and a negative electrode active material layer 17 provided on the other surface 15b of the current collector 15. The negative terminal electrode 13 does not include a positive electrode active material layer 16 and a negative electrode active material layer 17 on one surface 15a of the current collector 15. That is, no active material layer is provided on one surface 15a of the current collector 15 of the negative terminal electrode 13. The negative terminal electrode 13 is stacked on the bipolar electrode 11 at an end portion on the opposite side of the positive terminal electrode 12 in the first direction D1 of the electrode stack 10. The negative terminal electrode 13 is stacked on the bipolar electrode 11 in such a manner that its negative electrode active material layer 17 faces the positive electrode active material layer 16 of the bipolar electrode 11.

[0032] 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 disposed between the positive electrode active material layer 16 and the negative electrode active material layer 17. The separator 14 prevents a short circuit caused by contact between adjacent electrodes while allowing charge carriers such as lithium ions to pass through by isolating the positive electrode active material layer 16 from the negative electrode active material layer 17.

[0033] The current collector 15 is a chemically inert electrical conductor used to allow current to continue to flow through the positive electrode active material layer 16 and the negative electrode active material layer 17 during the discharge or charge of the lithium ion secondary battery. The material of the current collector 15 is, for example, a metal material, a conductive resin material, or a conductive inorganic material. As the conductive resin material, for example, a conductive polymer material or a resin formed by adding a conductive filler to a non-conductive polymer material as needed can be listed. The current collector 15 can also have a plurality of layers. In this case, each layer of the current collector 15 can also include the above-mentioned metal material and / or conductive resin material.

[0034] A coating layer may also be formed on the surface of the current collector 15. The coating layer may be formed by a known method such as plating or spraying. The current collector 15 may be, for example, in the form of a plate, a foil (such as a metal foil), a film, or a mesh. Examples of the metal foil include aluminum foil, copper foil, nickel foil, titanium foil, and stainless steel foil. The current collector 15 may also be an alloy foil of the above-mentioned metals or a foil obtained by integrating a plurality of metal foils. When the current collector 15 is in the form of a foil, the thickness of the current collector 15 may be, for example, 1 μm to 200 μm. In the present embodiment, the current collector 15 is a foil obtained by integrating aluminum foil and copper foil.

[0035] The positive electrode active material layer 16 contains a positive electrode active material that can absorb and release charge carriers such as lithium ions. Examples of the positive electrode active material include lithium composite metal oxides having a layered rock salt structure, metal oxides having a spinel structure, and polyanion compounds. The positive electrode active material can be any positive electrode active material that can be used in a lithium ion secondary battery. The positive electrode active material layer 16 may also contain a plurality of positive electrode active materials. In the present embodiment, the positive electrode active material layer 16 contains olivine-type lithium iron phosphate (LiFePO4) as a composite oxide.

[0036] The negative electrode active material layer 17 contains a negative electrode active material that can absorb and release charge carriers such as lithium ions. The negative electrode active material can be any one of a simple substance, an alloy or a compound. As the negative electrode active material, for example, lithium (Li), carbon, a metal compound, etc. can be listed. The negative electrode active material can also be an element or a compound thereof that can be alloyed with lithium. As carbon, for example, natural graphite, artificial graphite, hard carbon (difficult to graphitize carbon) or soft carbon (easy to graphitize carbon) can be listed. As artificial graphite, for example, highly oriented graphite, mesophase carbon microbeads, etc. can be listed. As elements that can be alloyed with lithium, silicon (silicon) or tin can be listed. In the present embodiment, the negative electrode active material layer 17 contains graphite as a carbon-based material.

[0037] The positive electrode active material layer 16 and the negative electrode active material layer 17 (hereinafter, sometimes referred to as "active material layer") may each contain a conductive aid for improving electrical conductivity, a binder, an electrolyte (polymer matrix, ion conductive polymer, electrolyte solution, etc.), an electrolyte supporting salt (lithium salt) for improving ion conductivity, etc. as needed. The conductive aid is added to improve the conductivity of each electrode (bipolar electrode 11, positive terminal electrode 12, negative terminal electrode 13). The conductive aid is, for example, acetylene black, carbon black, or graphite.

[0038] As the binder, there can be listed fluorine-containing resins such as polyvinylidene fluoride, polytetrafluoroethylene, fluorine rubber, 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, sodium alginate, alginates such as ammonium alginate, water-soluble cellulose ester crosslinked products, starch-acrylic acid graft polymers, etc. These binders can be used alone or in combination. For example, water, N-methyl-2-pyrrolidone (NMP), etc. are used as solvents.

[0039] The separator 14 may be, for example, a porous sheet or nonwoven fabric containing a polymer that absorbs and retains an electrolyte. Examples of the material of the separator 14 include polypropylene, polyethylene, polyolefin, polyester, and the like. The separator 14 may have a single-layer structure or a multi-layer structure. The multi-layer structure may have, 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 in the separator 14 is a liquid electrolyte (electrolyte) containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent.

[0040] As the electrolyte salt of the electrolyte, LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, LiN(CF3SO2)2 and other known lithium salts can be used. In addition, as the non-aqueous solvent, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, ethers can be used. In addition, two or more of these known solvent materials can also be used in combination.

[0041] Here, a detection line 30 is provided on the collector 15. The detection line 30 is configured and joined (e.g., ultrasonically welded) to the other surface 15b of the collector 15. As an example, one detection line 30 is provided on each collector 15 of all electrodes. Thus, in the power storage module 1, a pair of detection lines 30 adjacent along the first direction D1 can be used to detect the battery state (e.g., voltage) of a single cell (cell) composed of mutually adjacent electrodes. As an example, the detection line 30 is a voltage detection line.

[0042] The detection line 30 is in the form of a long foil strip, for example, made of metal. More specifically, the current collector 15 and the detection line 30 may be made of different metals, in which case the thermal conductivity of the metal constituting the detection line 30 may be lower than the thermal conductivity of the metal constituting the current collector 15. In this embodiment, the detection line 30 is a stainless steel foil.

[0043] The sealing body 20 is formed in a frame shape at the peripheral portion of the electrode stack 10 in a manner surrounding the electrode stack 10. The sealing body 20 can be joined (fused) to each of the one surface 15a and the other surface 15b of the current collector 15 in the peripheral portion 15c of each current collector 15. The sealing body 20 is used to form an internal space S between the current collectors 15 adjacent in the first direction D1 and to seal each of the internal spaces S. An electrolyte (e.g., an electrolyte solution) is contained in each internal space S. The sealing body 20 can prevent the electrolyte solution from penetrating to the outside.

[0044] In addition, the sealing body 20 can suppress the intrusion of moisture and the like from the outside of the electrode stack 10 into the internal space S. For example, the sealing body 20 can prevent the gas generated at each electrode due to the charge and discharge reaction and the like from leaking to the outside of the power storage module 1. The edge of the separator 14 is bonded to the sealing body 20. The sealing body 20 includes an insulating material. Examples of the material of the sealing body 20 include various resin materials such as polypropylene, polyethylene, polystyrene, ABS resin, acid-modified polypropylene, acid-modified polyethylene, and acrylonitrile styrene resin.

[0045] The sealing body 20 includes a plurality of seals 21 made of resin, a plurality of spacers 22 made of resin, and a welded end portion 23. The seal 21 is provided on each collector 15. Thus, the seals 21 are stacked one on another along the first direction D1. The seal 21 is frame-shaped (here, a rectangular frame-shaped) when viewed from the first direction D1, and is provided on the peripheral portion 15c of the collector 15. The seal 21 is provided in a manner of extending from one surface 15a of the collector 15 through the end surface to the other surface 15b, thereby covering the peripheral portion 15c. The seal 21 can be welded to one surface 15a and another surface 15b of the collector 15. Here, the seal 21 is welded to the collector 15 and the detection line 30 joined to the collector 15.

[0046] The spacer 22 is arranged in a manner interposed between each of the adjacent seals 21 in the first direction D1. Thus, the spacer 22 maintains the space between the adjacent seals 21, that is, between the adjacent collectors 15, and forms an internal space S together with the seal 21. The spacer 22 is frame-shaped (here, a rectangular frame-shaped) when viewed from the first direction D1, and is arranged on the peripheral portion 15c of the collector 15 when viewed from the first direction D1. Here, the end of the separator 14 is sandwiched between the seal 21 and the spacer 22 and is held therebetween. The separator 14 can be fused to at least one of the seal 21 and the spacer 22.

[0047] The welded end portion 23 is formed by welding and integrating the ends of the plurality of seals 21 and the plurality of spacers 22 on the side opposite to the internal space S. The welded end portion 23 is frame-shaped in a manner surrounding the electrode stack 10 when viewed from the first direction D1, and constitutes the outer periphery of the closed body 20. Thus, the closed body 20 has an outer side surface 20s (outer side surface of the welded end portion 23) formed by the first end surface 21s of the seal 21 on the side opposite to the internal space S and the second end surface 22s of the spacer 22 on the side opposite to the internal space S by welding the seal 21 and the spacer 22 to each other.

[0048] The detection line 30 extends from the collector 15 and is led out from the outer side surface 20s along the second direction D2 intersecting (orthogonal) with the first direction D1. Here, the outer side surface 20s is in a rectangular cylindrical shape and has four faces according to the outer shape of the seal 21 and the spacer 22. The lead-out portion 20p of the detection line 30 from the outer side surface 20s is concentrated on one of the four faces constituting the outer side surface 20s.

[0049] On the other hand, the lead portions 20p of the detection lines 30 adjacent in the first direction are arranged at different positions in a third direction D3 intersecting (orthogonal) the first direction D1 and the second direction D2. In the illustrated example, the lead portions 20p of the detection lines 30 are arranged along the first direction D1 in such a manner that the positions in the third direction D3 are different from each other. That is, the lead portions 20p of the detection lines 30 are dispersed in a plurality of (here, 2) positions in the third direction D3. On the other hand, at least two detection lines 30 (half in the illustrated example) among the plurality of detection lines 30 are configured to overlap each other when viewed from the first direction D1.

[0050] In addition, the portion of the detection line 30 that is closer to the electrode stack 10 than the outer side surface 20s is buried in the seal 21 in the portion where the seal 21 and the spacer 22 overlap along the first direction D1. Here, the detection line 30 is terminated inside the seal 21, and the entire portion of the detection line 30 that is closer to the electrode stack 10 than the outer side surface 20s is buried in the seal 21 and covered. As a result, the detection line 30 does not contact the spacer 22.

[0051] In addition, the material of the seal 21 can be appropriately selected from the materials of the above-mentioned sealing body 20, and as an example, it is a resin modified by acid. Therefore, when the collector 15 and the detection line 30 are made of metal, the bonding strength between the seal 21 and the collector 15 and the detection line 30 can be ensured. On the other hand, the material of the spacer 22 can also be appropriately selected from the materials of the above-mentioned sealing body 20, but it does not need to be a resin modified by acid.

[0052] Here, the outer side surface 20s of the sealing body 20 includes a protrusion 21k protruding along the second direction D2 (the lead-out direction of the detection line 30) to the side opposite to the electrode stack 10 in the lead-out portion 20p of the detection line 30. The protrusion 21k can be formed, for example, by making the first end surface 21s of the sealing member 21 protrude along the second direction D2 before forming the welded end portion 23. As described above, the lead-out portion 20p of the detection line 30 is concentrated on one of the four surfaces constituting the outer side surface 20s.

[0053] Therefore, the protrusion 21k is also formed only on one of the four surfaces constituting the outer side surface 20s. In addition, the protrusion 21k is formed in the third direction D3 with a width spanning a plurality of (here, two) positions where the lead-out portions 20p are provided. Here, when viewed from the first direction D1, one protrusion 21k is provided so as to span the lead-out portions 20p of all the detection lines 30.

[0054] The protrusions 21k at the lead-out portions 20p of the detection lines 30 that overlap each other when viewed from the first direction D1 (the protrusions 21k that overlap each other when viewed from the first direction D1) are separated from each other in the first direction D1. Therefore, on the outer side surface 20s of the sealing body 20, in the area between these adjacent protrusions 21k (for example, the area corresponding to the second end surface 22s of the spacer 22), a recess 22k that is recessed toward the electrode stack 10 side along the second direction D2 is formed. When forming the weld end 23, since the melted seal 21 and the spacer 22 are melted to each other, the melted resin flows from the protrusion 21k to the recess 22k, and the amount of resin between the seal 21 and the spacer 22 is much ensured. In addition, the protrusion 21k and the recess 22k are smoothly connected.

[0055] Figure 3 is a top view showing the relationship between the current collector, the detection line, and the seal. Figure 3 In FIG. 1 , the seal 21 is shown by a dotted line. Figure 3 As shown, the sealant 21 includes: a first region AR1, which overlaps with the collector 15 and is fused to the collector 15 when viewed from the first direction D1; and a second region AR2, which is located on the outside of the collector 15 when viewed from the first direction D1. The second region AR2 is a region that forms a fused end portion 23 by fusing with the spacer 22. The second region AR2 can be separated from the outer edge of the collector 15 as in the example shown in the figure. That is, it can be that only a portion of the portion of the sealant 21 located on the outside of the collector 15, which is close to the first end face 21s, forms the fused end portion 23 by fusing with the spacer 22. In addition, when the sealant 21 and the spacer 22 are fused to form the fused end portion 23, around the lead-out portion 20p of the detection line 30, heat sometimes escapes to the detection line 30, resulting in a smaller area where the sealant 21 and the spacer 22 are fused. Therefore, as Figure 2 and Figure 3 As shown, the width of the fused end portion 23 in the second direction D2 may become smaller around the lead-out portion 20 p of the detection line 30 .

[0056] The detection line 30 includes a first portion 31 and a second portion 32. The second portion 32 is a portion narrower than the first portion 31 when viewed from the first direction D1. Thus, in the detection line 30, a step portion 33 is formed between the first portion 31 and the second portion 32. The first portion 31 of the detection line 30 is configured from the first area AR1 to the second area AR2 of the seal 21, and the second portion 32 of the detection line 30 is configured from the second area AR2 of the seal 21 to the outside of the seal 21. The step portion 33 is located in the second area AR2.

[0057] The first portion 31 is provided with a notch 34. In the example shown in the figure, a pair of notches 34 are formed so as to be recessed from the outer edge of the first portion 31 toward the inside along the third direction D3 intersecting the second direction D2 as the lead-out direction of the detection line 30. The notch 34 is located in the first area AR1 of the seal 21. That is, the notch 34 is provided in the portion of the detection line 30 sandwiched by the collector 15 and the seal 21 along the first direction D1 (the portion of the first portion 31 overlapping the first area AR1).

[0058] Here, when manufacturing the power storage module 1, for example, the following process can be considered. That is, by welding the sealant 21 to the electrode including the collector 15 and the detection line 30, an electrode unit consisting of the electrode and the sealant 21 is formed. Next, the electrode unit is stacked with the separator 22 interposed therebetween. Thereafter, the sealant 21 and the separator 22 are welded to form the welded end 23.

[0059] As described above, the cutout 34 of the detection line 30 is located in the first region AR1 of the seal 21 welded to the current collector 15 (electrode). Therefore, the cutout 34 has an anchoring effect on the seal 21 from the time when the seal 21 is welded to the electrode to form an electrode unit, which helps to prevent the detection line 30 from falling off.

[0060] On the other hand, the step portion 33 of the detection line 30 is located in the second area AR2 of the seal 21 for welding with the spacer 22. Therefore, when the welded end portion 23 is formed by welding the seal 21 and the spacer 22, the step portion 33 has an anchoring effect on the welded end portion 23, which helps to prevent the detection line 30 from falling off.

[0061] As described above, in the power storage module 1, the electrode stack 10 is formed by stacking electrodes including the current collector 15 and the detection wire 30 joined to the current collector 15 along the first direction D1. The electrode stack 10 is provided with a sealing body 20 for sealing the internal space S between the current collectors 15. The sealing body 20 includes: a sealing member 21 fused to the current collector 15 and the detection wire 30; and a spacer 22 disposed between the sealing members 21 adjacent to each other in the first direction D1 and forming the internal space S together with the sealing member 21. The detection wire 30 is led out from the outer side surface 20s of the sealing body 20 formed by the sealing member 21 and the spacer 22 being fused.

[0062] In this way, in the power storage module 1, the seal 21 is provided as a resin member welded to the current collector 15 (and the detection line 30), and the spacer 22 is provided as another resin member between the seals 21. Therefore, while the seal 21 is made thinner to reduce the influence of the shrinkage of the seal 21 on the current collector 15, the increase in the thickness of the detection line 30 can be absorbed by ensuring the elastic deformation amount of the resin member by the spacer 22. Therefore, in the power storage module 1, the deformation of the current collector 15 and the increase in the local thickness of the electrode stack 10 can be suppressed.

[0063] In addition, in the battery module 1, the outer side surface 20s of the sealing body 20 includes a protrusion 21k protruding in the second direction D2 in the lead-out portion 20p of the detection line 30 from the outer side surface 20s. When the seal 21 and the spacer 22 are welded to form the outer side surface 20s, the seal 21 and the spacer 22 may not be fully welded around the lead-out portion 20p of the detection line 30 due to heat escape to the detection line 30, resulting in reduced sealing. In contrast, by providing the protrusion 21k on the outer side surface 20s of the sealing body 20 for the lead-out portion 20p of the detection line 30, a much larger amount of resin is ensured, so that the seal 21 and the spacer 22 can be more reliably welded to each other around the lead-out portion 20p, thereby improving the sealing.

[0064] In addition, when the seal 21 and the spacer 22 are welded, a heat source may be arranged to face the first end face 21s and the second end face 22s to perform heating. At this time, since the heat dissipation of the detection line 30 is good, the resin may be difficult to melt around the detection line 30. In contrast, in the power storage module 1, by providing the protrusion 21k around the detection line 30, the resin can be arranged closer to the heat source, thereby improving the sealing performance.

[0065] In addition, in the power storage module 1, the lead portions 20p of the plurality of detection lines 30 are dispersed at a plurality of positions in the third direction D3 by arranging the lead portions 20p adjacent to each other in the first direction D1 at different positions in the third direction D3. Furthermore, the protrusion 21k is formed with a width spanning the plurality of positions in the third direction D3. In this way, by arranging the lead portions 20p of the detection lines 30 adjacent to each other in the first direction D1 at different positions in the third direction D3, the isolation of the detection lines 30 in the first direction D1 is ensured.

[0066] In addition, at this time, by forming a protrusion 21k on the seal 21 with a width spanning multiple positions of the lead-out portion 20p where the detection line 30 is set, preparation of the seal 21 becomes easier than manufacturing multiple seals 21 each having a protrusion 21k corresponding to each of the multiple positions of the lead-out portion 20p.

[0067] In addition, in the power storage module 1, the current collector 15 and the detection wire 30 may be made of different metals, and the thermal conductivity of the metal constituting the detection wire 30 may be lower than the thermal conductivity of the metal constituting the current collector 15. In this case, the heat generated when the outer side surface 20s is formed by welding the seal 21 and the spacer 22 is suppressed from escaping to the current collector 15 through the detection wire 30, and poor welding of the seal 21 and the spacer 22 can be suppressed.

[0068] In the power storage module 1, the current collector 5 and the detection line 30 may be made of metal, and the seal 21 may be made of an acid-modified resin. In this case, the bonding strength between the seal 21 and the current collector 15 and the detection line 30 can be ensured, and the sealing performance can be improved.

[0069] In addition, in the storage battery module 1, the detection line 30 is embedded in the seal 21 in the portion where the seal 21 and the spacer 22 overlap along the first direction D1. Therefore, in the portion where the seal 21 and the spacer 22 overlap, the detection line 30 is embedded in the seal 21 made of an acid-modified resin that can be appropriately bonded to metal. Therefore, in this portion, even if the spacer 22 is not an acid-modified resin, it can be reliably sealed by fusing with the seal 21.

[0070] In addition, in the power storage module 1, at least two of the plurality of detection lines 30 are arranged to overlap each other when viewed from the first direction D1, and the protrusions 21k of the lead-out portions 20p of the detection lines 30 that overlap each other when viewed from the first direction D1 are separated from each other in the first direction D1. Therefore, by forming the concavoconvexity in the lead-out portion 20p of the detection line 30 on the outer side surface 20s, the creepage distance between the adjacent detection lines 30 in the first direction D1 becomes longer, thereby suppressing the short circuit between the detection lines 30.

[0071] Furthermore, in the power storage module 1, the notch 34 is provided at the portion of the detection line 30 sandwiched by the collector 15 and the seal 21 along the first direction D1. Therefore, the detection line 30 is prevented from falling off by the anchoring effect brought about by the notch. In particular, since the notch 34 is provided at the portion of the detection line 30 sandwiched by the collector 15 and the seal 21, the anchoring effect is exerted from the time when the seal 21 is welded to the collector 15 and the detection line 30, and the detection line 30 is prevented from falling off.

[0072] The above embodiment is an embodiment for explaining one aspect of the power storage module. Therefore, the above power storage module 1 can be modified arbitrarily.

[0073] For example, in the above embodiment, the detection line 30 is provided with the notch 34 that is recessed along the third direction D3. However, the recessed direction of the notch 34 is arbitrary, for example, it may be the second direction D2.

[0074] In addition, in the above-mentioned embodiment, a scheme in which the protrusion 21k is provided in the lead-out portion 20p of the detection line 30 on the outer side surface 20s of the closing body 20 is described. However, the protrusion 21k may not be provided on the outer side surface 20s of the closing body 20. When the sealing member 21 and the spacer 22 are welded around the lead-out portion 20p of the detection line 30, the protrusion 21k may not be provided in the case where the weld end portion 23 can be formed with a sufficient weld width by further increasing the amount of heat, etc.

[0075] Furthermore, the thermal conductivity of the detection wire 30 may be higher than that of the current collector 15 , and the current collector 15 and the detection wire 30 may be made of the same material.

[0076] In the above embodiment, the detection line 30 is exemplified as a voltage detection line. However, the detection line 30 may be a temperature detection line connected to a temperature sensor provided in the electrode stack 10 .

[0077] Hereinafter, additional notes will be given on the above-mentioned embodiments.

[0078] A storage module is, [1] "a storage module comprising: an electrode stack, which is a plurality of electrodes stacked along a first direction and having a current collector provided with an active material layer and a detection line connected to the current collector; and a sealing body, which is arranged on the electrode stack in a manner surrounding the electrode stack and is used to seal an internal space between the current collectors adjacent to each other in the first direction, the sealing body comprising: a plurality of resin sealants, which are fused to each of the plurality of electrodes; a plurality of resin spacers, which are arranged between the sealants adjacent to each other in the first direction and form the internal space together with the sealants; and an outer side surface, which is formed by a first end surface of the sealant on the side opposite to the internal space and a second end surface of the spacer on the side opposite to the internal space by fusing the sealant and the spacer to each other, the plurality of sealants are each fused to the current collector and the detection line connected to the current collector, the detection line extends from the current collector and is led out from the outer side surface along a second direction intersecting the first direction".

[0079] The power storage module may be [2] “the power storage module according to [1] above, wherein the outer side surface includes a protrusion protruding in the second direction at a portion of the detection line led out from the outer side surface”.

[0080] The power storage module may also be, [3] "the power storage module according to the above [2], wherein the lead portions of the plurality of detection lines are dispersed at a plurality of positions in the third direction by arranging the lead portions adjacent to each other in the first direction at different positions in a third direction intersecting the first direction and the second direction, and the protrusion is formed in the third direction with a width spanning the plurality of positions".

[0081] The power storage module may also be, [4] "the power storage module according to the above-mentioned [2] or [3], wherein at least two of the plurality of detection lines are configured to overlap with each other when viewed from the first direction, and the protrusions at the lead-out parts of the detection lines that overlap with each other when viewed from the first direction are separated from each other in the first direction."

[0082] The power storage module may also be, [5] "the power storage module according to any one of [1] to [4] above, wherein the collector and the detection line are made of metals different from each other, and the thermal conductivity of the metal constituting the detection line is lower than the thermal conductivity of the metal constituting the collector."

[0083] The power storage module may also be, [6] "the power storage module according to any one of [1] to [5] above, wherein the collector and the detection line are made of metal, and the seal is made of an acid-modified resin."

[0084] The power storage module may be [7] “the power storage module according to [6] above, wherein the detection line is embedded in the sealing member in a portion where the sealing member and the spacer overlap along the first direction”.

[0085] The power storage module may also be, [8] "the power storage module according to any one of [1] to [7] above, wherein a cutout is provided in a portion of the detection line sandwiched between the collector and the seal along the first direction."

[0086] Industrial Applicability

[0087] According to the present disclosure, it is possible to provide a power storage module capable of suppressing deformation of a current collector and suppressing increase in local thickness of a stacked body.

[0088] Description of Reference Numerals

[0089] 1 ... power storage module, 10 ... electrode stack, 15 ... current collector, 20 ... sealing body, 20s ... outer side surface, 20p ... lead portion, 21 ... sealing member, 21s ... first end surface, 21k ... protrusion, 22 ... spacer, 22s ... second end surface, 22k ... recess, 30 ... detection line, 34 ... cutout.

Claims

1. A power storage module, characterized in that: have: an electrode stack including a current collector provided with an active material layer and a plurality of electrodes connected to the current collector and stacked in a first direction; and a sealing body, which is arranged on the electrode stack in a manner surrounding the electrode stack and is used to seal the internal space between the collectors adjacent in the first direction, The enclosure has: a plurality of sealing members made of resin, which are welded to each of the plurality of electrodes; a plurality of resin spacers disposed between the sealing members adjacent to each other in the first direction and forming the internal space together with the sealing members; as well as an outer side surface formed by a first end surface of the seal member on the side opposite to the internal space and a second end surface of the spacer on the side opposite to the internal space by welding the seal member and the spacer to each other, The plurality of seals are each fused to the current collector and the detection wire joined to the current collector, The detection line extends from the current collector and is led out from the outer side surface along a second direction intersecting the first direction.

2. The power storage module according to claim 1, wherein: The outer side surface includes a protrusion protruding toward the second direction in a portion of the detection line led out from the outer side surface.

3. The power storage module according to claim 2, wherein: The lead portions of the plurality of detection lines are dispersed at a plurality of positions in the third direction by disposing the lead portions adjacent to each other in the first direction at different positions in a third direction intersecting the first direction and the second direction. The protrusion is formed with a width spanning the plurality of locations in the third direction.

4. The power storage module according to claim 2, wherein: At least two of the plurality of detection lines are arranged to overlap each other when viewed from the first direction, The protrusions at the respective lead-out portions of the detection lines that overlap each other when viewed from the first direction are separated from each other in the first direction.

5. The power storage module according to claim 1, wherein: The current collector and the detection line are made of different metals. The thermal conductivity of the metal constituting the detection line is lower than the thermal conductivity of the metal constituting the current collector.

6. The power storage module according to claim 1, wherein: The current collector and the detection line are made of metal, The sealing member is composed of an acid-modified resin.

7. The power storage module according to claim 6, wherein: The detection line is embedded in the sealing member in a portion where the sealing member and the spacer overlap along the first direction.

8. The power storage module according to any one of claims 1 to 7, wherein: A cutout is provided at a portion of the detection line sandwiched between the collector and the seal member along the first direction.

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