Power storage module

Abstract

To provide a power storage module capable of suppressing liquid junction between terminals.SOLUTION: The energy storage module 100 includes an electrode stacked body 10 having a plurality of electrodes stacked along the Z-axis direction, a sealing body 20 which surrounds the electrode stacked body 10 as viewed in the Z-axis direction and seals an inner space S formed between the electrodes disposed adjacently to each other in the Z-axis direction, and a plurality of terminals 300 respectively provided to the plurality of electrodes. The sealing body 20 includes a plurality of frame-shaped sealing members 21 welded to peripheral edge portions of the plurality of electrodes, and a resin portion 24 provided on side surfaces of the plurality of sealing members 21 and overlapping with the plurality of terminals when viewed from the Z-axis direction. Each of the plurality of terminals 300 penetrates the injection molded resin portion in the Y-axis direction and has a terminal body 301 made of a conductive material and an insulating layer 302 covering a portion of the terminal body 301 overlapping with the resin portion 24 when viewed from the Z-axis direction.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage module. [Background technology]

[0002] Patent Document 1 discloses a secondary battery having a plurality of electrodes stacked with a solid electrolyte interposed therebetween and a sealed portion. Each of the electrodes is connected to a tab for detecting the voltage of the electrode. The tab extends to the outside of the sealed portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-319362 Summary of the Invention [Problem to be solved by the invention]

[0004] Like the tabs mentioned above, terminal ends that extend outside the secondary battery are sometimes housed in a resin part to facilitate connection to a voltage measuring device. The resin part is provided with multiple terminal housings that can separately house each of the multiple terminal ends. The resin part may be attached to the secondary battery by injection molding resin. If voids are formed in the injection molding resin and electrolyte seeps into the voids, there is a risk of liquid junctions between the terminals.

[0005] The present disclosure provides an energy storage module that can suppress liquid shorts between terminals. [Means for solving the problem]

[0006] The energy storage module according to the present disclosure comprises an electrode stack having a plurality of electrodes stacked along a first direction, a sealing body that surrounds the electrode stack when viewed from the first direction and seals an internal space formed between adjacent electrodes in the first direction, and a plurality of terminals provided on each of the plurality of electrodes, wherein the sealing body has a plurality of frame-shaped sealing members welded to the peripheral portions of the plurality of electrodes, and injection-molded resin portions that are provided on the side surfaces of the plurality of sealing members and overlap with the plurality of terminals when viewed from the first direction, and each of the plurality of terminals penetrates the injection-molded resin portion in a second direction perpendicular to the first direction, and has a terminal body made of a conductive material and an insulating layer that covers the portion of the terminal body that overlaps with the injection-molded resin portion when viewed from the first direction.

[0007] In the above-described energy storage module, the terminal includes a terminal body and an insulating layer. The insulating layer covers a portion of the terminal body that overlaps with the injection-molded resin portion when viewed from the first direction. Therefore, even if a void is formed in the injection-molded resin portion and the electrolyte enters the void, a liquid junction between the terminals can be prevented.

[0008] The terminal body has a connection portion connected to the electrode, a protrusion portion extending along the second direction and protruding outside the multiple sealing members, and a deforming portion arranged between the connection portion and the protrusion portion, wherein the deforming portion has a first flat plate portion and a second flat plate portion connected to the first flat plate portion, wherein the first flat plate portion has a first surface extending in the second direction and a third direction perpendicular to the first and second directions and is more easily elastically deformed in the first direction than the second flat plate portion, and the second flat plate portion has a second surface extending in the first and second directions and is more easily elastically deformed in the third direction than the first flat plate portion, and the insulating layer may cover the deforming portion.

[0009] The injection-molded resin portion may have a resin portion that overlaps with a part of the protrusion when viewed from the first direction, and the resin portion may have a tapered shape that tapers toward the tip of the protrusion.

[0010] The tip of the protrusion may be exposed from the insulating layer.

[0011] The connection portion may be exposed from the insulating layer.

[0012] The insulating layer may overlap a portion of the terminal body that is located closer to the electrode stack than the side surface when viewed from the first direction.

[0013] The above-mentioned energy storage module may further include a resin part having a plurality of terminal accommodating portions that accommodate a plurality of terminals, the resin part having an opposing surface that faces the side surface, the injection-molded resin part having a resin layer interposed between the side surface and the opposing surface, and the insulating layer overlapping the resin layer when viewed from the first direction. [Effects of the Invention]

[0014] According to the present disclosure, it is possible to provide an energy storage module that can prevent liquid short circuits between terminals. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view of an electricity storage module according to one embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the electricity storage module. [Figure 3] FIG. 3 is a cross-sectional view of the electricity storage module. [Figure 4] FIG. 4 is a perspective view of the terminal. [Figure 5] FIG. 5 is a plan view showing the positional relationship between the terminals and the sealing body. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment will be described below with reference to the drawings. In the description of the drawings, identical or equivalent elements are denoted by the same reference numerals, and redundant description may be omitted. In the description, a Cartesian coordinate system defined by the X-axis, Y-axis, and Z-axis shown in the drawings may be referenced.

[0017] As shown in FIG. 1, an energy storage module 100 according to one embodiment includes a module main body, a plurality of terminals 300, and a resin part 400. FIG. 1 schematically illustrates a state before the resin part 400 is attached. The energy storage module 100 is, for example, a nickel-metal hydride secondary battery or a lithium-ion secondary battery. The energy storage module 100 may also be, for example, an electric double layer capacitor. In this embodiment, the energy storage module 100 is a lithium-ion secondary battery.

[0018] As shown in FIGS. 2 and 3, the module main body 200 includes an electrode stack 10 and a sealing body 20. FIG. 2 schematically illustrates a state before a resin part 400 is attached. FIG. 3 schematically illustrates a state after the resin part 400 is attached. The electrode stack 10 has, for example, a rectangular parallelepiped shape. The electrode stack 10 has a plurality of electrodes stacked along the Z-axis direction (first direction). The plurality of electrodes includes a plurality of bipolar electrodes 11, a positive terminal electrode 12, and a negative terminal electrode 13. Separators 14 are interposed between adjacent electrodes.

[0019] The bipolar electrode 11 includes a current collector 15, a first active material layer 16, and a second 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.

[0020] The first active material layer 16 is provided on the surface 15a. The first active material layer 16 is, for example, a positive electrode active material layer. When viewed from the Z-axis direction, the first active material layer 16 has, for example, a rectangular shape. The surface 15a includes an uncoated region where the first active material layer 16 is not provided. When viewed from the Z-axis direction, the uncoated region surrounds the first active material layer 16.

[0021] The second active material layer 17 is provided on the surface 15b. The polarity of the second active material layer 17 is different from the polarity of the first active material layer 16. The second active material layer 17 is, for example, a negative electrode active material layer. When viewed from the Z-axis direction, the second active material layer 17 has, for example, a rectangular shape. The surface 15b includes an uncoated region where the second active material layer 17 is not provided. When viewed from the Z-axis direction, the uncoated region surrounds the second active material layer 17. When viewed from the Z-axis direction, the area of ​​the second active material layer 17 is larger than the area of ​​the first active material layer 16. When viewed from the Z-axis direction, the outer edge of the second active material layer 17 is located outside the outer edge of the first active material layer 16.

[0022] The multiple bipolar electrodes 11 are stacked so that the first active material layer 16 of one bipolar electrode 11 faces the second active material layer 17 of another bipolar electrode 11. In other words, the multiple bipolar electrodes 11 are stacked so 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.

[0023] The positive terminal electrode 12 is disposed on one side of the bipolar electrodes 11 in the Z-axis direction. The positive terminal electrode 12 includes a current collector 15 and a first active material layer 16. The positive terminal electrode 12 differs from the bipolar electrodes 11 primarily in that it does not include a second active material layer 17. The other configurations of the positive terminal electrode 12 may be the same as those of the bipolar electrode 11. The first active material layer 16 of the positive terminal electrode 12 faces the second active material layer 17 of the bipolar electrode 11. That is, the positive terminal electrode 12 is stacked such that the surface 15a of the current collector 15 of the positive terminal electrode 12 faces the surface 15b of the current collector 15 of the bipolar electrode 11 adjacent to the positive terminal electrode 12.

[0024] The negative terminal electrode 13 is disposed on the other side of the plurality of bipolar electrodes 11 in the Z-axis direction. The negative terminal electrode 13 has a current collector 15 and a second active material layer 17. The negative terminal electrode 13 differs from the bipolar electrode 11 mainly in that it does not have a first active material layer 16. Other configurations of the negative terminal electrode 13 may be the same as those of the bipolar electrode 11. The second active material layer 17 of the negative terminal electrode 13 faces the first 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.

[0025] 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.

[0026] 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 first and second active material layers 16 and 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 further outward than the outer edges of the first and second active material layers 16 and 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, thereby preventing electrical shorts due to contact between the electrodes 11, 12, and 13. The separators 14 absorb and retain the electrolyte.

[0027] The current collector 15 has the function of maintaining the flow of current in the first active material layer 16 and the second active material layer 17 during discharging or charging of the energy storage module 100. 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.

[0028] 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 in the form of a foil, 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.

[0029] The first 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 (LiFePO4), LiCoO2, LiNiMnCoO2, or the like.

[0030] The second active material layer 17 contains 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.

[0031] Each of the first active material layer 16 and the second 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 the conductive network in 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.

[0032] Formation of the first active material layer 16 on the surface 15a and the second 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. The active material layer-forming composition 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 its density.

[0033] The electrolyte is contained in the internal space S. The separator 14 is impregnated with the electrolyte. The electrolyte 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 is, for example, a known lithium salt such as LiClO4, LiAsF6, LiPF6, LiBF4, LiCF3SO3, LiN(FSO2)2, or LiN(CF3SO2)2. The non-aqueous solvent is, for example, a cyclic carbonate, a cyclic ester, a chain carbonate, a chain ester, or an ether. Two or more of these known solvent materials may be used in combination.

[0034] The sealing body 20 surrounds the electrode stack 10 when viewed from the Z-axis direction. The sealing body 20 seals the internal space S formed between adjacent electrodes in the Z-axis direction. The sealing body 20 includes a plurality of frame-shaped sealing members 21, a plurality of frame-shaped spacers 22, a welded portion 23, and a resin portion 24 (injection-molded resin portion). The sealing member 21 has, for example, a rectangular frame shape. The sealing member 21 covers the peripheral portion 15c of each current collector 15. The sealing member 21 is provided on the surface 15a and the surface 15b of each current collector 15. The sealing member 21 surrounds the first active material layer 16 and the second active material layer 17 when viewed from the Z-axis direction. The inner edges of the sealing member 21 are spaced apart from the first active material layer 16 and the second active material layer 17. The plurality of sealing members 21 are welded to the peripheral portions 15c of the plurality of current collectors 15.

[0035] The spacer 22 has, for example, a rectangular frame shape. The spacer 22 is provided between adjacent sealing members 21. The spacer 22 is sandwiched between adjacent sealing members 21. The inner peripheral portion of the spacer 22 overlaps with the second active material layer 17 when viewed from the Z-axis direction. The inner peripheral portion of the spacer 22 is located between the surface 15a of the current collector 15 and the second active material layer 17.

[0036] The welded portion 23 is formed by welding the outer edges of the seal members 21 and the spacers 22 together. The welded portion 23 has, for example, a rectangular cylindrical shape. The welded portion 23 has a side surface 23a extending along the Z-axis direction. The side surface 23a includes the side surfaces of the multiple seal members 21 and the side surfaces of the multiple spacers 22.

[0037] The resin part 24 is formed by injection molding so as to fill the gap between the welded portion 23 and the resin part 400. Voids V may be formed in the resin part 24. The resin part 24 is formed when the resin part 400 is attached to the module main body 200. As described above, FIG. 2 shows the state before the resin part 400 is attached to the module main body 200, i.e., the state before the resin part 24 is formed. Therefore, the resin part 24 is not shown in FIG. 2.

[0038] The resin portion 24 is provided on the side surface 23a of the welded portion 23. It can also be said that the resin portion 24 is provided on the side surfaces of the plurality of sealing members 21 and the side surfaces of the plurality of spacers 22. The resin portion 24 overlaps with the plurality of terminals 300 when viewed from the Z-axis direction. The resin portion 24 covers the plurality of terminals 300.

[0039] The resin portion 24 has a resin layer 25 interposed between the side surface 23a of the welded portion 23 and the side surface 401 of the resin part 400. When viewed from the Z-axis direction, the resin portion 24 has a plurality of resin portions 26 that overlap with parts of the protruding portions 330 of the plurality of terminals 300. The number of resin portions 26 is the same as the number of terminals 300, and one resin portion 26 is provided for one terminal 300. The resin portions 26 have a tapered shape that tapers toward the tip portions 330b of the protruding portions 330. The sizes of the resin portions 26 (lengths in the X-axis direction and lengths in the Z-axis direction) become shorter as they approach the tip portions 330b in the Y-axis direction.

[0040] The sealing member 21, the spacer 22, and the resin portion 24 are each made of a material such as acid-modified polyethylene (acid-modified PE), acid-modified polypropylene (acid-modified PP), polyethylene, or polypropylene. The sealing member 21 and the spacer 22 are both electrolyte-resistant. The sealing member 21 and the spacer 22 may be made of the same material or different materials. In this embodiment, the sealing member 21 is made of, for example, acid-modified polyethylene or acid-modified polypropylene. In this embodiment, the spacer 22 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 21 to the current collector 15 can be improved by making the sealing member 21 from acid-modified polyethylene or acid-modified polypropylene.

[0041] The plurality of terminals 300 are provided on the plurality of electrodes, respectively, and detect the voltages of the plurality of electrodes. Each of the plurality of terminals 300 is provided on a corresponding one of the plurality of electrodes. For example, the number of terminals 300 is the same as the number of electrodes, with one terminal 300 provided for each electrode. The terminal 300 is provided on the surface 15b of each current collector 15 and electrically connected to the surface 15b. The terminal 300 is provided between the surface 15b of the current collector 15 and the sealing member 21. The terminal 300 is formed of a metal such as stainless steel.

[0042] The terminals 300 extend from the inside of the sealing body 20 to the outside of the sealing body 20. For example, as shown in FIG. 1, the multiple terminals 300 are arranged in a predetermined region on one side surface of the module main body 200 that is perpendicular to the Y-axis direction. In this predetermined region, the multiple terminals 300 are arranged so as to be aligned linearly in the Z-axis direction and the X-axis direction, i.e., in a grid pattern. The distance between the terminals 300 in the X-axis direction is, for example, 5 mm or more and 30 mm or less. The distance between the terminals 300 in the Z-axis direction is, for example, 1 mm or more and 10 mm or less.

[0043] The resin part 400 is a member that protects the multiple terminals 300 protruding from the side surface 23a of the welded portion 23. The resin part 400 is provided with multiple terminal accommodating sections 410 that can accommodate each of the multiple terminals 300 individually. The multiple terminal accommodating sections 410 are arranged in a lattice pattern corresponding to the multiple terminals 300. As shown in FIG. 3, the resin part 400 has a side surface 401 (opposing surface) that faces the side surface 23a of the welded portion 23 in the Y-axis direction, and a side surface 402 that faces the opposite side in the Y-axis direction from the side surface 401. The terminal accommodating section 410 is a through hole that passes through the resin part 400 in the Y-axis direction.

[0044] The terminal accommodating portion 410 has a wide portion 411, a tapered portion 412, a narrow portion 413, and an insertion portion 414. The wide portion 411, the tapered portion 412, the narrow portion 413, and the insertion portion 414 are arranged in this order from the side surface 401 to the side surface 402. The wide portion 411 opens to the side surface 401. The tapered portion 412 connects the wide portion 411 and the narrow portion 413. The insertion portion 414 opens to the side surface 402. A connector (not shown) of a voltage measuring device is inserted into the insertion portion 414.

[0045] The length of narrow portion 413 in the Z-axis direction is shorter than the length of wide portion 411 in the Z-axis direction. Although not shown in the figure, the length of narrow portion 413 in the X-axis direction is shorter than the length of wide portion 411 in the X-axis direction. The size of wide portion 411 (length in the Z-axis direction and length in the X-axis direction) is set so as to provide sufficient clearance with respect to the size of protrusion 330 of terminal 300. The size of narrow portion 413 is set so as to provide a slight clearance with respect to the size of protrusion 330. The size of narrow portion 413 is set to be approximately equal to the size of protrusion 330.

[0046] The tapered portion 412 is formed in a tapered shape. The size of the tapered portion 412 gradually decreases with increasing distance from the electrode stack 10 in the Y-axis direction. Because the size of the wide portion 411 is larger than the size of the narrow portion 413, the terminal 300 can be easily inserted into the wide portion 411 (terminal accommodating portion 410). The tapered portion 412 makes it possible to guide the position of the terminal 300. Furthermore, the tapered portion 412 prevents the protruding portion 330 from being covered with resin when the resin portion 24 is formed by injection molding.

[0047] The resin portion 26 described above is filled into the terminal accommodating portion 410 so as to fill the space between the terminal 300 and the terminal accommodating portion 410. The resin portion 26 has a shape corresponding to the shape of the terminal accommodating portion 410.

[0048] As shown in FIGS. 1 to 4 , the terminal 300 extends along the Y-axis direction as a whole. The terminal 300 includes a terminal body 301 and an insulating layer 302. The terminal body 301 penetrates the resin portion 24 in the Y-axis direction. The terminal body 301 is made of a conductive material such as metal. The insulating layer 302 is made of an insulating material. The insulating layer 302 is made of a resin material such as polyamide. The melting point of the insulating layer 302 is higher than the melting point of the material of the resin portion 24, for example. This prevents the insulating layer 302 from melting due to heat generated during injection molding of the resin portion 24. The insulating layer 302 covers a portion of the terminal body 301 that overlaps with the resin portion 24 when viewed from the Z-axis direction.

[0049] Terminal body 301 has a connecting portion 310, a deforming portion 320, a protruding portion 330, and a partition wall 340. Connection portion 310 is one end portion (base end portion) in the Y-axis direction, and protruding portion 330 is the other end portion (tip end portion) in the Y-axis direction. Deforming portion 320 is disposed between connection portion 310 and protruding portion 330 in the Y-axis direction. Terminal body 301 is formed, for example, by bending a single thin metal plate having a thickness of 0.05 mm to 0.5 mm.

[0050] The connection portion 310 is a portion connected to an electrode. The connection portion 310 is a thin metal plate whose thickness direction is in the Z-axis direction. The connection portion 310 has a main surface 310a extending in the Y-axis direction and the X-axis direction. The main surface 310a is continuous with a main surface 321a (first surface) of the first flat plate portion 321 (described later) and forms the same plane. When viewed from the Z-axis direction, the connection portion 310 has, for example, a rectangular shape with its longer side oriented in the Y-axis direction and its shorter side oriented in the X-axis direction. The connection portion 310 extends in the X-axis direction and the Y-axis direction. The connection portion 310 is inserted into the electrode stack 10 and surface-bonded to the surface 15b of the current collector 15. The connection portion 310 is, for example, ultrasonically welded to the surface 15b of the current collector 15. Because the connection portion 310 is made of a thin plate, tearing (foil tearing) of the electrode foil constituting the current collector 15 is unlikely to occur.

[0051] The protrusion 330 extends along the Y-axis direction and protrudes outward from the multiple seal members 21. The protrusion 330 is a rod-shaped member whose axis is the Y-axis direction. The protrusion 330 has a hollow structure. The hollow portion of the protrusion 330 extends in the Y-axis direction. The protrusion 330 is formed by deforming a thin metal plate into a cylindrical or groove shape. The protrusion 330 includes a tip portion 330b that tapers toward the tip 330a in the Y-axis direction. The tapered shape of the tip portion 330b facilitates insertion of the protrusion 330 into the terminal accommodating portion 410 of the resin part 400. The protrusion 330 is connected to a connector of a voltage measuring device. The outer surface of the protrusion 330 is, for example, gold-plated. This facilitates electrical continuity between the terminal 300 and the connector of the voltage measuring device. The protrusion 330 is, for example, formed in a groove shape with a U-shaped cross section.

[0052] The deforming portion 320 deforms to match the position of the corresponding terminal accommodating portion 410, making it easier to insert the protruding portion 330 into the corresponding terminal accommodating portion 410. The deforming portion 320 includes a first flat plate portion 321, a second flat plate portion 322, a third flat plate portion 323, and a fourth flat plate portion 324. One end of the first flat plate portion 321 in the Y-axis direction is connected to the connecting portion 310. The thickness direction of the first flat plate portion 321 is the Z-axis direction, and the first flat plate portion 321 is more easily elastically deformed in the Z-axis direction than the second flat plate portion 322. The first flat plate portion 321 has a main surface 321a (first surface) extending in the Y-axis direction and the X-axis direction. As described above, the main surface 321a is continuous with the main surface 310a and forms the same plane.

[0053] When viewed from the Z-axis direction, the first flat plate portion 321 has, for example, a rectangular shape with its longer side oriented in the Y-axis direction and its shorter side oriented in the X-axis direction. The first flat plate portion 321 and the connecting portion 310 are connected so that their centers in the X-axis direction coincide with each other. The width of the first flat plate portion 321 in the X-axis direction is shorter than the width of the connecting portion 310 in the X-axis direction. This makes the first flat plate portion 321 more likely to deform in the Z-axis direction. The second moment of area of ​​the first flat plate portion 321 in the Z-axis direction is smaller than the second moment of area in the X-axis direction, and the first flat plate portion 321 is more likely to elastically deform in the Z-axis direction.

[0054] One end of the second flat plate portion 322 in the Y-axis direction is connected to the other end of the first flat plate portion 321 in the Y-axis direction. The thickness direction of the second flat plate portion 322 is the X-axis direction. The second flat plate portion 322 has a smaller second moment of area in the X-axis direction than the second moment of area in the Z-axis direction, making it more susceptible to elastic deformation in the X-axis direction. The second flat plate portion 322 is more susceptible to elastic deformation in the X-axis direction than the first flat plate portion 321. The second flat plate portion 322 has a main surface 322a (second surface) extending in the Y-axis and Z-axis directions. When viewed from the X-axis direction, the second flat plate portion 322 has, for example, a substantially rectangular shape with its longer side extending in the Y-axis direction and its shorter side extending in the Z-axis direction. The first flat plate portion 321 and the second flat plate portion 322 are connected to each other via a bent portion formed, for example, by bending a thin metal plate at a right angle.

[0055] One end of the third flat plate portion 323 in the Y-axis direction is connected to the other end of the second flat plate portion 322 in the Y-axis direction. The third flat plate portion 323 extends in the Z-axis direction and has a main surface 323a (third surface) that is inclined in the X-axis and Y-axis directions. The third flat plate portion 323 is more easily elastically deformed in the X-axis direction than the first flat plate portion 321, and is less easily elastically deformed in the Z-axis direction than the first flat plate portion 321. The second flat plate portion 322 and the third flat plate portion 323 are connected to each other via a bent portion formed by bending a thin metal plate, for example.

[0056] One end of the fourth flat plate portion 324 in the Y-axis direction is connected to the other end of the third flat plate portion 323 in the Y-axis direction. The thickness direction of the fourth flat plate portion 324 is the X-axis direction. The fourth flat plate portion 324 is more easily elastically deformed in the X-axis direction than the first flat plate portion 321, and is less easily elastically deformed in the Z-axis direction than the first flat plate portion 321. In the fourth flat plate portion 324, the second flat plate portion 322 and the fourth flat plate portion 324 are arranged parallel to each other. The fourth flat plate portion 324 has a main surface 324a (fourth surface) extending in the Y-axis direction and the Z-axis direction. The third flat plate portion 323 and the fourth flat plate portion 324 are connected to each other via a bent portion formed by bending a thin metal plate, for example.

[0057] The second flat plate portion 322, the third flat plate portion 323, and the fourth flat plate portion 324 are all more susceptible to elastic deformation in the X-axis direction than the first flat plate portion 321. When ultrasonically welding the terminal 300 to the current collector 15, there is a risk that a fragile portion of the terminal 300 may be damaged. In this embodiment, the third flat plate portion 323, which extends in a direction inclined with respect to the Y-axis direction, is provided between the second flat plate portion 322 and the fourth flat plate portion 324, which extend in the Y-axis direction. This configuration can prevent the fragile portion of the terminal 300 from being damaged by vibrations when ultrasonically welding the connection portion 310 to the current collector 15. The fragile portion of the terminal 300 is, for example, a bent portion of the metal plate or a portion of the metal plate where the width is narrow.

[0058] The partition wall 340 is provided between the protruding portion 330 and the deforming portion 320. The partition wall 340 separates the hollow portion of the protruding portion 330 from the space in which the deforming portion 320 is provided. The partition wall 340 extends in the Z-axis direction and the X-axis direction. The partition wall 340 is disposed in the tapered portion 412 of the terminal accommodating portion 410.

[0059] When the resin portion 24 is formed by injection molding, if the resin penetrates beyond the deformed portion 320 and adheres to the second portion 332 of the protruding portion 330, the area of ​​the conductive surface of the deformed portion 320 will be reduced. This may result in poor contact between the terminal 300 and the connector of the voltage measuring device. The partition wall 340 functions as a blocking portion that prevents the resin from penetrating into the protruding portion 330. The partition wall 340 has an outer surface that is continuous with the outer surface 331a of the first portion 331 of the protruding portion 330 via a bent portion. The partition wall 340 is formed by bending the end of a metal plate that forms the side wall of the groove in the first portion 331.

[0060] The insulating layer 302 covers, for example, the deformation portion 320. The insulating layer 302 covers, for example, the first flat plate portion 321. The insulating layer 302 covers, for example, the entire surface of the terminal body 301 within a predetermined range in the Y-axis direction. The insulating layer 302 is not provided on the connection portion 310 connected to the current collector 15 or on the tip portion 330b of the protrusion 330 connected to the connector of the voltage measuring device. The connection portion 310 and the tip portion 330b of the protrusion 330 are exposed from the insulating layer 302. The insulating layer 302 overlaps with the resin layer 25 when viewed from the Z-axis direction. The insulating layer 302 also overlaps with a portion of the terminal body 301 that is located closer to the electrode stack 10 than the side surface 23a of the welded portion 23 when viewed from the Z-axis direction.

[0061] FIG. 5 shows the positional relationship between the terminal 300 and the sealing body 20. Here, the sealing body 20 is indicated by a dashed line. As shown in FIG. 5, at least a portion of the deforming portion 320, together with the protruding portion 330, protrudes outside the welded portion 23. In this example, at least a portion of the first flat plate portion 321 and the entire second flat plate portion 322 protrude outside the welded portion 23. Therefore, before the resin part 400 is attached, i.e., before the resin part 24 is provided, the deforming portion 320 can elastically deform in the Z-axis and X-axis directions. By attaching the resin part 400 to the terminal 300 in this state, the protruding portion 330 is positioned appropriately, and damage to the terminal 300 and the terminal accommodating portion 410 can be suppressed.

[0062] After the resin part 400 is attached to the terminal 300, resin is injected between the resin part 400 and the welded portion 23 by injection molding to form the resin part 24. This fixes the resin part 400 to the module main body 200. The resin also enters the interior of the terminal accommodating part 410 from the opening on the side surface 401 side of the terminal accommodating part 410. Therefore, the resin part 24 is formed so as to overlap a part of the protruding part 330 when viewed from the Z-axis direction.

[0063] As described above, the size (hole diameter) of the terminal accommodating portion 410 is smaller in the central portion in the Y-axis direction, so the resin does not enter the space on the side surface 402 side of the terminal accommodating portion 410. Therefore, the resin portion 24 is not formed on the tip portion 330b of the protrusion 330. The insulating layer 302 also covers a portion of the terminal body 301 that is located on the electrode laminate 10 side of the resin portion 24 when viewed from the Z-axis direction. For example, the insulating layer 302 covers a portion of the terminal body 301 that overlaps with the welded portion 23 when viewed from the Z-axis direction. In the illustrated example, the insulating layer 302 does not cover a portion of the terminal body 301 that overlaps with the sealing member 21 when viewed from the Z-axis direction, but it may do so.

[0064] As described above, in the energy storage module 100, the terminal 300 has a terminal body 301 and an insulating layer 302. The insulating layer 302 covers the portion of the terminal body 301 that overlaps with the resin portion 24 when viewed from the Z-axis direction. Therefore, as shown in Fig. 3, even if a void V is formed in the resin portion 24 and an electrolyte solution enters the void V, it is possible to prevent liquid junctions between the terminals 300.

[0065] Because the terminals 300 are accommodated one by one in the terminal accommodating section 410, even if voids V are formed inside the terminal accommodating section 410, liquid junctions are unlikely to occur between the terminals 300. In contrast, if voids V are formed in the resin layer 25, liquid junctions are likely to occur between the terminals 300. In the energy storage module 100, the insulating layer 302 covers the terminal body 301 so as to overlap with the resin layer 25 when viewed from the Z-axis direction, and therefore, even if voids V are formed in the resin layer 25, liquid junctions between the terminals 300 can be suppressed.

[0066] Although examples of the embodiments of the present disclosure have been described above with reference to the drawings, the present disclosure is not limited to the above embodiments.

[0067] For example, the terminal 300 may not have the deformation portion 320. In this case, the connection portion 310 and the protrusion 330 may be directly connected. The protrusion 330 may not be formed in a groove shape with a U-shaped cross section. The protrusion 330 may be formed in a flat plate shape with its thickness direction in the Z-axis direction. In this case, the entire terminal body 301 is formed in a flat plate shape with its thickness direction in the Z-axis direction. The energy storage module 100 is only required to include at least one terminal 300. This makes it possible to prevent a liquid short circuit between at least one terminal 300 and the other terminals, even if the other terminals do not have an insulating layer.

[0068] The form of the present disclosure can be shown as follows. [Article 1] an electrode stack having a plurality of electrodes stacked along a first direction; a sealing body that surrounds the electrode stack when viewed from the first direction and seals an internal space formed between the electrodes adjacent to each other in the first direction; a plurality of terminals provided on the plurality of electrodes, respectively; Equipped with The sealing body is a plurality of frame-shaped sealing members welded to peripheral edges of the plurality of electrodes; injection-molded resin portions provided on side surfaces of the plurality of sealing members and overlapping the plurality of terminals when viewed from the first direction; and Each of the plurality of terminals is a terminal body made of a conductive material and penetrating the injection-molded resin portion in a second direction perpendicular to the first direction; an insulating layer covering a portion of the terminal body that overlaps with the injection-molded resin portion when viewed from the first direction; It has Energy storage module. [Clause 2] the terminal body has a connection portion connected to the electrode, a protrusion portion extending along the second direction and protruding outward from the plurality of sealing members, and a deformation portion disposed between the connection portion and the protrusion portion, the deformation portion has a first flat plate portion and a second flat plate portion connected to the first flat plate portion, the first flat plate portion has a first surface extending in the second direction and a third direction perpendicular to the first direction and the second direction, and is more easily elastically deformed in the first direction than the second flat plate portion; the second flat plate portion has a second surface extending in the first direction and the second direction, and is more easily elastically deformed in the third direction than the first flat plate portion; The insulating layer covers the deformation portion. 1. The energy storage module according to clause 1. [Article 3] the injection-molded resin portion has a resin portion that overlaps with a part of the protrusion when viewed from the first direction, The resin portion has a tapered shape that tapers toward the tip of the protrusion. 1. The energy storage module according to clause 1. [Article 4] a tip end of the protrusion is exposed from the insulating layer; 4. The energy storage module according to clause 2 or 3. [Article 5] the connection portion is exposed from the insulating layer. The electricity storage module according to any one of clauses 2 to 4. [Article 6] the insulating layer overlaps a portion of the terminal body that is closer to the electrode stack than the side surface when viewed from the first direction. 6. The power storage module according to any one of items 1 to 5. [Article 7] a resin part provided with a plurality of terminal accommodating portions for accommodating the plurality of terminals; the resin part has an opposing surface that faces the side surface, the injection-molded resin portion has a resin layer interposed between the side surface and the opposing surface, the insulating layer overlaps the resin layer when viewed from the first direction. The electricity storage module according to any one of items 1 to 6. [Explanation of symbols]

[0069] 10...electrode laminate, 15c...periphery, 11...bipolar electrode, 12...positive terminal electrode, 13...negative terminal electrode, 20...sealing body, 21...sealing member, 23a...side surface, 24...resin portion (injection-molded resin portion), 25...resin layer, 26...resin portion, 100...energy storage module, 300...terminal, 301...terminal body, 302...insulating layer, 310...connection portion, 320...deformation portion, 321...first flat plate portion, 321a...main surface (first surface), 322...second flat plate portion, 322a...main surface (second surface), 330...protrusion, 330b...tip portion, 400...resin part, 401...side surface (opposing surface), 410...terminal accommodating portion, S...internal space.

Claims

1. an electrode stack having a plurality of electrodes stacked along a first direction; a sealing body that surrounds the electrode stack as viewed from the first direction and seals an internal space formed between the electrodes adjacent to each other in the first direction; a plurality of terminals provided on the plurality of electrodes, respectively; Equipped with The sealing body is a plurality of frame-shaped sealing members welded to peripheral edges of the plurality of electrodes; injection-molded resin portions provided on side surfaces of the plurality of sealing members and overlapping the plurality of terminals when viewed from the first direction; and Each of the plurality of terminals is a terminal body made of a conductive material and penetrating the injection-molded resin portion in a second direction perpendicular to the first direction; an insulating layer covering a portion of the terminal body that overlaps with the injection-molded resin portion when viewed from the first direction; It has Energy storage module.

2. the terminal body has a connection portion connected to the electrode, a protrusion portion extending along the second direction and protruding outward from the plurality of sealing members, and a deformation portion disposed between the connection portion and the protrusion portion, the deformation portion has a first flat plate portion and a second flat plate portion connected to the first flat plate portion, the first flat plate portion has a first surface extending in the second direction and a third direction perpendicular to the first direction and the second direction, and is more easily elastically deformed in the first direction than the second flat plate portion; the second flat plate portion has a second surface extending in the first direction and the second direction, and is more easily elastically deformed in the third direction than the first flat plate portion; The insulating layer covers the deformation portion. The energy storage module according to claim 1 .

3. the injection-molded resin portion has a resin portion that overlaps with a part of the protrusion when viewed from the first direction, The resin portion has a tapered shape that tapers toward the tip of the protrusion. The energy storage module according to claim 2 .

4. a tip end of the protrusion is exposed from the insulating layer; The energy storage module according to claim 2 or 3.

5. the connection portion is exposed from the insulating layer. The energy storage module according to claim 2 or 3.

6. the insulating layer overlaps a portion of the terminal body that is closer to the electrode stack than the side surface when viewed from the first direction. The storage module according to any one of claims 1 to 3.

7. a resin part provided with a plurality of terminal accommodating portions for accommodating the plurality of terminals; the resin part has an opposing surface that faces the side surface, the injection-molded resin portion has a resin layer interposed between the side surface and the opposing surface, the insulating layer overlaps the resin layer when viewed from the first direction; The storage module according to any one of claims 1 to 3.

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