Battery

Abstract

To provide a battery in which damage to an electrode tab group is suitably prevented.SOLUTION: A battery 100 according to an embodiment includes a sealing plate 14 and an insulating member 70. The insulating member 70 is joined by insulating sheets 29 arranged so as to cover electrode bodies 20a, 20b, and 20c, and the insulating sheet 29 includes a sheet bottom wall 29a, a pair of sheet first sidewalls 29b extending from the sheet bottom wall 29a and facing each other, and a pair of sheet second sidewalls 29c extending from the sheet bottom wall 29a and facing each other.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to a battery. [Background technology]

[0002] Batteries such as lithium-ion secondary batteries generally include an electrode assembly having electrodes, an exterior body having an opening and housing the electrode assembly, a sealing plate that seals the opening of the exterior body, and a terminal that is electrically connected to the electrode inside the exterior body and extends from the sealing plate to the exterior of the exterior body. This type of battery is typically known to have a configuration in which an electrode tab group including multiple tabs for current collection is provided on the electrode, and the electrode is connected to the terminal via the electrode tab group. For example, Patent Document 1 listed below discloses a battery in which a positive electrode tab group is provided at one longitudinal end of the electrode assembly and a negative electrode tab group is provided at the other longitudinal end. The patent document also discloses a technology in which the electrode tab group is bent and connected to an electrode current collector. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-50069 Summary of the Invention [Problem to be solved by the invention]

[0004] When a battery is in use, it may be subjected to external vibrations, shocks, and the like. The tab, which is made of, for example, a part of the current collector, is soft and easily affected by external forces. Furthermore, the inventors' studies have found that if the electrode body is displaced from its predetermined position by an external force (for example, an external force applied in the longitudinal direction of the electrode body), the bent portion of the tab (in other words, the curved portion of the tab) is easily damaged. This is undesirable because it may cause the electrical connection between the electrode and the terminal to become unstable or to become poorly connected.

[0005] The present invention has been made in view of the above circumstances, and its main object is to provide a battery in which damage to the electrode tab group is suitably prevented. [Means for solving the problem]

[0006] The present invention provides a battery comprising one or more electrode assemblies including a positive electrode and a negative electrode, and a battery case housing the electrode assemblies. The battery case comprises an exterior body having a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall, and a sealing plate sealing the opening, with a positive electrode terminal and a negative electrode terminal attached to the sealing plate. The electrode body includes a positive electrode tab group protruding from an end facing one of the pair of second side walls and a negative electrode tab group protruding from an end facing the other of the pair of second side walls, the positive electrode tab group and the positive electrode terminal being electrically connected via a positive electrode current collector, the positive electrode tab group being joined to the positive electrode current collector in a curved state so that a portion of the positive electrode tab group is positioned along the one second side wall, the negative electrode tab group and the negative electrode terminal being electrically connected via a negative electrode current collector, and the negative electrode tab group being joined to the negative electrode current collector in a curved state so that a portion of the negative electrode tab group is positioned along the other second side wall. The sealing plate is provided with an insulating member. An insulating sheet is joined to the insulating member and arranged to cover the electrode body, and the insulating sheet has at least a sheet bottom wall and a pair of sheet first side walls extending from the sheet bottom wall and facing each other, and the sheet first side walls face the first side walls.

[0007] In this way, with a configuration in which the sealing plate is provided with an insulating member and an insulating sheet is bonded to the insulating member so as to cover the electrode body, the electrode body can be firmly fixed to the sealing plate, and therefore, the electrode body can be effectively prevented from being displaced from its predetermined position due to, for example, an external force applied in the longitudinal direction of the electrode body, thereby effectively preventing damage to the electrode tab group.

[0008] In one aspect of the battery disclosed herein, the insulating sheet further includes a sheet second side wall disposed between the second side wall and the electrode body.

[0009] In the battery of this aspect, the second side wall of the sheet is separated into a current collecting region where the positive electrode tab group or the negative electrode tab group is present, and a non-current collecting region where the positive electrode tab group or the negative electrode tab group is not present.

[0010] In a preferred embodiment of the battery disclosed herein, the insulating member has a rectangular wide surface, and the length of the short side of the wide surface is shorter than the thickness of the electrode assembly. When the length of the short side of the wide surface of the insulating member is shorter than the thickness of the electrode assembly, the insulating sheet has a tapered shape on the sealing plate side. This more firmly fixes the insulating sheet and the electrode assembly, thereby more effectively preventing the electrode assembly from shifting from its predetermined position due to, for example, an external force applied in the longitudinal direction of the electrode assembly, and consequently more effectively preventing damage to the electrode tab group.

[0011] In a preferred embodiment of the battery disclosed herein, the sheet bottom wall is rectangular, and the length of the short side of the sheet bottom wall is shorter than the thickness of the electrode assembly. When the length of the short side of the sheet bottom wall of the insulating sheet is shorter than the thickness of the electrode assembly, the insulating sheet has a tapered shape toward the bottom wall. This more firmly secures the insulating sheet and the electrode assembly, thereby more effectively preventing the electrode assembly from shifting from its predetermined position due to, for example, an external force applied in the longitudinal direction of the electrode assembly, and consequently more effectively preventing damage to the electrode tab group.

[0012] In a preferred embodiment of the battery disclosed herein, at least a portion of the insulating sheet is joined to the electrode assembly. This configuration more firmly fixes the insulating sheet and the electrode assembly, thereby more effectively preventing the electrode assembly from shifting from its predetermined position due to, for example, an external force applied in the longitudinal direction of the electrode assembly. This more effectively prevents damage to the electrode tab group.

[0013] In a preferred embodiment of the battery disclosed herein, at least a portion of the joint between the insulating member and the insulating sheet is located within a range of (¼)L or less in a direction along the first side wall from the center of the electrode body, where L is the length of the electrode body in the direction along the first side wall. Fixing the insulating sheet at a position close to the center of the electrode body in this manner is preferable because it can suitably prevent the insulating sheet from sagging.

[0014] In a preferred embodiment of the battery disclosed herein, a fixing member is disposed on each of the pair of sheet first side walls, extending from one sheet first side wall to the other sheet first side wall. This configuration more firmly fixes the insulating sheet and the electrode assembly, thereby more effectively preventing the electrode assembly from shifting from its predetermined position due to, for example, an external force applied in the longitudinal direction of the electrode assembly. This more effectively prevents damage to the electrode tab group.

[0015] In a preferred embodiment of the battery disclosed herein, a movement restricting member is disposed between the sheet second side wall and the electrode assembly. This configuration can more effectively prevent the electrode assembly from being displaced from its predetermined position due to, for example, an external force applied in the longitudinal direction of the electrode assembly. This can more effectively prevent damage to the electrode tab group.

[0016] In one aspect of the battery disclosed herein, the insulating member is disposed between the positive electrode current collector and the negative electrode current collector and the sealing plate.

[0017] In one aspect of the battery disclosed herein, the insulating member is fixed to the sealing plate by adhesion or fitting. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view schematically illustrating a battery according to an embodiment. [Figure 2] FIG. 2 is a schematic longitudinal sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a schematic vertical cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 2 is a perspective view schematically showing an electrode assembly attached to a sealing plate. [Figure 6] FIG. 2 is a perspective view schematically showing an electrode assembly to which a positive electrode second current collecting portion and a negative electrode second current collecting portion are attached. [Figure 7] FIG. 2 is a schematic diagram showing the configuration of a wound electrode body. [Figure 8] 10 is a perspective view schematically showing a sealing plate to which a positive electrode terminal, a negative electrode terminal, a positive electrode first current collecting portion, a negative electrode first current collecting portion, and an insulating member are attached. FIG. [Figure 9] FIG. 9 is a perspective view of the sealing plate of FIG. 8 turned upside down. [Figure 10] FIG. 9 is a schematic perspective view for explaining the sealing plate alone in FIG. 8. [Figure 11] FIG. 9 is a schematic perspective view for explaining an insulating member in FIG. 8. [Figure 12] FIG. 12 is a perspective view of the insulating member of FIG. 11 turned upside down. [Figure 13] FIG. 2 is a schematic development view for explaining the insulating sheet according to the first embodiment. [Figure 14] 14 is a schematic perspective view of the insulating sheet of FIG. 13 disposed so as to cover the electrode assembly of FIG. 5. FIG. [Figure 15] 5A to 5C are schematic cross-sectional views illustrating a battery insertion step according to one embodiment. [Figure 16]FIG. 10 is a schematic development view for explaining an insulating sheet according to a second embodiment. [Figure 17] 10A and 10B are schematic diagrams illustrating an expanded view of an insulating sheet according to a third embodiment and a fixing member. [Figure 18] 10A and 10B are schematic diagrams illustrating an expanded view of an insulating sheet according to a fourth embodiment and a fixing member. [Figure 19] FIG. 10 is a schematic development view for explaining an insulating sheet according to a fifth embodiment. [Figure 20] FIG. 10 is a schematic development view for explaining an insulating sheet according to a sixth embodiment. [Figure 21] FIG. 10 is a schematic diagram for explaining a battery according to another embodiment. [Figure 22] FIG. 10 is a schematic diagram for explaining a battery according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, some preferred embodiments of the technology disclosed herein will be described with reference to the drawings. It should be noted that matters other than those specifically mentioned in this specification but necessary for implementing the present invention (for example, the general configuration and manufacturing process of a battery that do not characterize the present invention) can be understood as design matters for a person skilled in the art based on the prior art in the relevant field. The present invention can be implemented based on the contents disclosed in this specification and the technical common sense in the relevant field. The following explanation is not intended to limit the technology disclosed herein to the following embodiments. Furthermore, in this specification, the notation "A to B" indicating a numerical range means greater than A and less than B. Therefore, it includes the case where the value is greater than A and less than B.

[0020] In this specification, the term "battery" refers to any power storage device capable of extracting electrical energy, and is a concept that encompasses primary batteries and secondary batteries. In addition, in this specification, the term "secondary battery" refers to any power storage device that can be repeatedly charged and discharged, and is a concept that encompasses so-called storage batteries (chemical batteries) such as lithium-ion secondary batteries and nickel-metal hydride batteries, and capacitors (physical batteries) such as electric double layer capacitors.

[0021] <Battery 100> FIG. 1 is a perspective view of a battery 100. FIG. 2 is a schematic longitudinal cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a schematic longitudinal cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a schematic transverse cross-sectional view taken along line IV-IV in FIG. 1. In the following description, the symbols L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, top, and bottom, and the symbols X, Y, and Z in the drawings represent the short side direction of the battery 100, the long side direction perpendicular to the short side direction (which can also be referred to as the longitudinal direction of the electrode body), and the up-down direction, respectively. However, these directions are merely used for convenience of description and do not limit the installation form of the battery 100 in any way.

[0022] As shown in FIG. 2, the battery 100 includes a battery case 10 and an electrode assembly 20 (specifically, electrode assemblies 20a, 20b, and 20c). The battery 100 according to this embodiment includes, in addition to the battery case 10 and the electrode assembly 20, a positive electrode terminal 30, a positive electrode external conductive member 32, a negative electrode terminal 40, a negative electrode external conductive member 42, an external insulating member 92, a positive electrode current collector 50, a negative electrode current collector 60, and an insulating member 70. Although not shown, the battery 100 according to this embodiment also includes an electrolyte. The battery 100 is a lithium-ion battery. In the battery 100 according to this embodiment, the sealing plate 14 is provided with an insulating member 70, and an insulating sheet 29 is joined to the insulating member 70, which is disposed so as to cover the electrode assemblies 20a, 20b, and 20c. The insulating sheet disclosed herein includes at least a sheet bottom wall and a pair of sheet first side walls extending from the sheet bottom wall and facing each other. As will be described in detail later, the insulating sheet 29 according to this embodiment includes a sheet bottom wall 29a, a pair of sheet first side walls 29b extending from the sheet bottom wall 29a and facing each other, and a pair of sheet second side walls 29c disposed between the second side wall 12c and the electrode assembly (here, the electrode assembly group 20) (see FIG. 14). As shown in FIG. 4, the sheet first side wall 29b faces the first side wall 12b, and the sheet second side wall 29c faces the second side wall 12c. The insulating member 70 and the insulating sheet 29 are examples of the insulating member and insulating sheet disclosed herein, respectively.

[0023] The battery case 10 is a housing that houses the electrode assembly 20. Here, the battery case 10 has a flat, bottomed, rectangular parallelepiped (rectangular) outer shape. The material of the battery case 10 may be the same as that used conventionally, and is not particularly limited. The battery case 10 is preferably made of a metal having a predetermined strength. Specifically, the tensile strength of the metal used for the battery case 10 is 50 N / mm 2 ~200N / mm 2 The physical property value (modulus of rigidity) of the metal used for the battery case 10 is preferably about 20 GPa to 100 GPa. Examples of this type of metal material include aluminum, aluminum alloys, iron, and iron alloys.

[0024] The battery case 10 includes an exterior body 12, a sealing plate 14, and a gas release valve 17. The exterior body 12 is a flat, rectangular container with an opening 12h on one side. Specifically, as shown in FIG. 1 , the exterior body 12 includes a substantially rectangular bottom wall 12a, a pair of first side walls 12b extending upward in a U-shape from a short side of the bottom wall 12a and facing each other, and a pair of second side walls 12c extending upward in a U-shape from a long side of the bottom wall 12a and facing each other. The area of ​​the second side walls 12c is smaller than the area of ​​the first side walls 12b. The opening 12h is formed on the upper surface of the exterior body 12, which is surrounded by the pair of first side walls 12c and the pair of second side walls 12b. The sealing plate 14 is attached to the exterior body 12 so as to close the opening 12h of the exterior body 12. The sealing plate 14 is a substantially rectangular plate material in a plan view. The sealing plate 14 faces the bottom wall 12a of the exterior body 12. The battery case 10 is formed by joining (e.g., welding) the sealing plate 14 to the periphery of the opening 12h of the exterior body 12. The joining of the sealing plate 14 can be performed by welding, for example, laser welding. Specifically, each of the pair of second side walls 12c is joined to a short side of the sealing plate 14, and each of the pair of first side walls 12b is joined to a long side of the sealing plate 14.

[0025] As shown in FIGS. 1 and 2, the gas release valve 17 is formed on the sealing plate 14. The gas release valve 17 is configured to open when the pressure inside the battery case 10 reaches or exceeds a predetermined value, thereby releasing gas inside the battery case 10. In addition to the gas release valve 17, the sealing plate 14 is also provided with a liquid injection hole 15 and two terminal insertion holes 18 and 19. The liquid injection hole 15 communicates with the internal space of the exterior body 12 and is an opening provided for injecting electrolyte during the manufacturing process of the battery 100. The liquid injection hole 15 is sealed with a sealing member 16. A blind rivet, for example, is a suitable example of such a sealing member 16.

[0026] FIG. 5 is a perspective view schematically illustrating an electrode assembly 20 attached to a sealing plate 14. In this embodiment, a plurality of (here, three) electrode assemblies 20a, 20b, and 20c are housed inside the battery case 10. The number of electrode assemblies 20 housed inside one battery case 10 is not particularly limited and may be one or two or more (plural). As shown in FIG. 2, a positive electrode current collector 50 is disposed on one side of each electrode assembly 20 in the long side direction Y (left side in FIG. 2), and a negative electrode current collector 60 is disposed on the other side of each electrode assembly 20 in the long side direction Y (right side in FIG. 2). The electrode assemblies 20a, 20b, and 20c are connected in parallel. However, the electrode assemblies 20a, 20b, and 20c may also be connected in series. The electrode assemblies 20 are housed inside the exterior body 12 of the battery case 10 while covered with an insulating sheet 29 (see FIG. 3). As the material for insulating sheet 29, any material that can be used for insulating sheets of this type of battery can be used without any particular limitation. An example of the material for insulating sheet 29 is a resin film such as polyethylene (PE). Note that similar materials can also be used for insulating sheets 129, 229, 329, 429, and 529, which will be described later.

[0027] Fig. 6 is a perspective view showing a schematic view of the electrode body 20a. Fig. 7 is a schematic view showing the configuration of the electrode body 20a. Note that, although the electrode body 20a will be described in detail below as an example, the electrode bodies 20b and 20c can also have a similar configuration.

[0028] As shown in FIG. 7, the electrode assembly 20a has a positive electrode 22, a negative electrode 24, and a separator 26. Here, the electrode assembly 20a is a wound electrode assembly in which a strip-shaped positive electrode 22 and a strip-shaped negative electrode 24 are stacked with two strip-shaped separators 26 interposed therebetween, and wound around a winding axis WL. However, the structure of the electrode assembly does not limit the technology disclosed herein. For example, the electrode assembly may be a laminated electrode assembly in which multiple square-shaped (typically rectangular) positive electrodes and multiple square-shaped (typically rectangular) negative electrodes are stacked in an insulated state.

[0029] The electrode body 20a has a flat shape. The electrode body 20a is disposed inside the exterior body 12 with the winding axis WL oriented approximately parallel to the long side direction Y. Specifically, as shown in Fig. 3, the electrode body 20a has a pair of curved portions (R portions) 20r that face the bottom wall 12a and the sealing plate 14 of the exterior body 12, and a flat portion 20f that connects the pair of curved portions 20r and faces the second side wall 12b of the exterior body 12. The flat portion 20f extends along the second side wall 12b.

[0030] As shown in FIG. 7, the positive electrode 22 includes a positive electrode current collector 22c, a positive electrode active material layer 22a, and a positive electrode protective layer 22p adhered to at least one surface of the positive electrode current collector 22c. However, the positive electrode protective layer 22p is not essential and may be omitted in other embodiments. The positive electrode current collector 22c is strip-shaped. The positive electrode current collector 22c is made of a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. In this example, the positive electrode current collector 22c is a metal foil, specifically, an aluminum foil.

[0031] A plurality of positive electrode tabs 22t are provided at one end of the positive electrode current collector 22c in the long side direction Y (the left end in FIG. 7). The plurality of positive electrode tabs 22t are provided at intervals (intermittently) along the longitudinal direction of the strip-shaped positive electrode 22. The plurality of positive electrode tabs 22t protrude outward beyond the separator 26 toward one axial side of the winding axis WL (the left side in FIG. 7). The positive electrode tabs 22t may be provided on the other axial side of the winding axis WL (the right side in FIG. 7), or on both axial sides of the winding axis WL. The positive electrode tabs 22t are part of the positive electrode current collector 22c and are made of metal foil (aluminum foil). However, the positive electrode tabs 22t may be a member separate from the positive electrode current collector 22c. In at least a part of the positive electrode tab 22t, the positive electrode active material layer 22a and the positive electrode protective layer 22p are not formed, and a region where the positive electrode current collector 22c is exposed is formed.

[0032] As shown in FIG. 4, the positive electrode tabs 22t are stacked at one axial end (the left end in FIG. 4) of the winding axis WL to form a positive electrode tab group 23. The positive electrode tab group 23 protrudes from an end facing one of the pair of second side walls 12c. A portion of the positive electrode tab group 23 (specifically, a portion in contact with the positive electrode second current collecting portion 52) is arranged along the second side wall. This improves the fitment into the battery case 10, enabling the battery 100 to be miniaturized. As shown in FIG. 2, the positive electrode tab group 23 is electrically connected to the positive electrode terminal 30 via the positive electrode current collecting portion 50. Specifically, the positive electrode tab group 23 and the positive electrode second current collecting portion 52 are connected at a connection portion J (see FIG. 4). The positive electrode second current collecting portion 52 is electrically connected to the positive electrode terminal 30 via the positive electrode first current collecting portion 51. The sizes of the multiple positive electrode tabs 22t (the length along the long side direction Y and the width perpendicular to the long side direction Y, see FIG. 7 ) can be adjusted appropriately, for example, by their formation positions, taking into consideration the state of connection to the positive electrode current collecting portion 50. Here, the multiple positive electrode tabs 22t are different in size from one another so that the outer ends are aligned when bent.

[0033] As shown in FIG. 7, the positive electrode active material layer 22a is provided in a strip-like shape along the longitudinal direction of the strip-shaped positive electrode current collector 22c. The positive electrode active material layer 22a contains a positive electrode active material (e.g., a lithium transition metal composite oxide such as a lithium nickel cobalt manganese composite oxide) capable of reversibly absorbing and releasing charge carriers. When the total solid content of the positive electrode active material layer 22a is taken as 100 mass%, the positive electrode active material may account for approximately 80 mass% or more, typically 90 mass% or more, for example, 95 mass% or more. The positive electrode active material layer 22a may contain optional components other than the positive electrode active material, such as a conductive material, a binder, various additives, etc. Examples of the conductive material include a carbon material such as acetylene black (AB). Examples of the binder include polyvinylidene fluoride (PVdF).

[0034] As shown in FIG. 7, the positive electrode protective layer 22p is provided at the boundary between the positive electrode collector 22c and the positive electrode active material layer 22a in the long side direction Y. Here, the positive electrode protective layer 22p is provided at one end (the left end in FIG. 7) of the positive electrode collector 22c in the axial direction of the winding axis WL. However, the positive electrode protective layer 22p may be provided at both ends in the axial direction. The positive electrode protective layer 22p is provided in a strip shape along the positive electrode active material layer 22a. The positive electrode protective layer 22p contains an inorganic filler (e.g., alumina). When the entire solid content of the positive electrode protective layer 22p is taken as 100% by mass, the inorganic filler may account for approximately 50% by mass or more, typically 70% by mass or more, for example, 80% by mass or more. The positive electrode protective layer 22p may contain optional components other than the inorganic filler, such as a conductive material, a binder, and various additive components. The conductive material and binder may be the same as those exemplified as those that may be contained in the positive electrode active material layer 22a.

[0035] As shown in Fig. 7, the negative electrode 24 includes a negative electrode current collector 24c and a negative electrode active material layer 24a fixed to at least one surface of the negative electrode current collector 24c. The negative electrode current collector 24c is strip-shaped. The negative electrode current collector 24c is made of a conductive metal such as copper, a copper alloy, nickel, or stainless steel. In this example, the negative electrode current collector 24c is a metal foil, specifically a copper foil.

[0036] A plurality of negative electrode tabs 24t are provided at one axial end (the right end in FIG. 7) of the winding axis WL of the negative electrode current collector 24c. The plurality of negative electrode tabs 24t are provided at intervals (intermittently) along the longitudinal direction of the strip-shaped negative electrode 24. Each of the plurality of negative electrode tabs 24t protrudes outward from the separator 26 toward one axial end (the right end in FIG. 7). However, the negative electrode tab 24t may be provided at the other axial end (the left end in FIG. 7) or at each of both axial end portions. The negative electrode tab 24t is part of the negative electrode current collector 24c and is made of metal foil (copper foil). However, the negative electrode tab 24t may be a separate member from the negative electrode current collector 24c. At least a portion of the negative electrode tab 24t has a region where the negative electrode active material layer 24a is not formed and the negative electrode current collector 24c is exposed.

[0037] As shown in FIG. 4, the negative electrode tabs 24t are stacked at one axial end (the right end in FIG. 4) to form a negative electrode tab group 25. The negative electrode tab group 25 protrudes from an end of the pair of second side walls 12c that faces the other second side wall. The negative electrode tab group 25 is preferably provided symmetrically to the positive electrode tab group 23 in the axial direction. A portion of the negative electrode tab group 25 (specifically, a portion that contacts the negative electrode second current collecting portion 62) is arranged along the second side wall. This improves the fitment into the battery case 10 and enables the battery 100 to be miniaturized. As shown in FIG. 2, the negative electrode tab group 25 is electrically connected to the negative electrode terminal 40 via the negative electrode current collecting portion 60. Specifically, the negative electrode tab group 25 and the negative electrode second current collecting portion 62 are connected at a connection portion J (see FIG. 4). The negative electrode second current collecting portion 62 is electrically connected to the negative electrode terminal 40 via the negative electrode first current collecting portion 61. As with the multiple positive electrode tabs 22t, the multiple negative electrode tabs 24t here have different sizes so that the outer edges of the tabs are aligned when bent.

[0038] As shown in FIG. 7, the negative electrode active material layer 24a is provided in a strip-like shape along the longitudinal direction of a strip-shaped negative electrode current collector 24c. The negative electrode active material layer 24a contains a negative electrode active material (e.g., a carbon material such as graphite) that can reversibly store and release charge carriers. When the total solid content of the negative electrode active material layer 24a is taken as 100 mass%, the negative electrode active material may account for approximately 80 mass% or more, typically 90 mass% or more, for example 95 mass% or more. The negative electrode active material layer 24a may contain optional components other than the negative electrode active material, such as a binder, a dispersant, and various additives. Examples of the binder that can be used include rubbers such as styrene butadiene rubber (SBR). Examples of the dispersant that can be used include celluloses such as carboxymethyl cellulose (CMC).

[0039] As shown in FIG. 7, the separator 26 is a member that insulates the positive electrode active material layer 22a of the positive electrode 22 from the negative electrode active material layer 24a of the negative electrode 24. A suitable example of the separator 26 is a porous resin sheet made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP). The separator 26 may have a substrate made of a porous resin sheet and a heat resistance layer (HRL) containing an inorganic filler and provided on at least one surface of the substrate. Examples of inorganic fillers that can be used include alumina, boehmite, aluminum hydroxide, and titania.

[0040] The electrolyte may be the same as conventional ones and is not particularly limited. The electrolyte is, for example, a non-aqueous electrolyte containing a non-aqueous solvent and a supporting salt. The non-aqueous solvent contains, for example, carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. The supporting salt is, for example, a fluorine-containing lithium salt such as LiPF6. However, the electrolyte may be in a solid state (solid electrolyte) and integrated with the electrode assembly 20.

[0041] As shown in FIG. 2, the positive electrode terminal 30 is inserted into a terminal insertion hole 18 formed at one end of the sealing plate 14 in the long side direction Y (the left end in FIG. 2). The positive electrode terminal 30 is preferably made of metal, more preferably aluminum or an aluminum alloy. Meanwhile, the negative electrode terminal 40 is inserted into a terminal insertion hole 19 formed at the other end of the sealing plate 14 in the long side direction Y (the right end in FIG. 2). The negative electrode terminal 40 is preferably made of metal, more preferably copper or a copper alloy. Here, these electrode terminals (positive electrode terminal 30, negative electrode terminal 40) each protrude from the same surface of the battery case 10 (specifically, the sealing plate 14). However, the positive electrode terminal 30 and the negative electrode terminal 40 may each protrude from different surfaces of the battery case 10. The electrode terminals (positive electrode terminal 30, negative electrode terminal 40) inserted into the terminal insertion holes 18, 19 are preferably fixed to the sealing plate 14 by crimping or the like.

[0042] As described above, as shown in FIG. 2, the positive electrode terminal 30 is electrically connected to the positive electrode 22 (see FIG. 7) of each electrode body 20 via the positive electrode current collecting portion 50 (positive electrode first current collecting portion 51, positive electrode second current collecting portion 52) inside the exterior body 12. The positive electrode terminal 30 is insulated from the sealing plate 14 by the insulating member 70 and the gasket 90. The positive electrode terminal 30 exposed to the outside of the battery case 10 through the terminal insertion hole 18 is connected to the positive electrode external conductive member 32 outside the sealing plate 14. Meanwhile, as shown in FIG. 2, the negative electrode terminal 40 is electrically connected to the negative electrode 24 (see FIG. 7) of each electrode body 20 via the negative electrode current collecting portion 60 (negative electrode first current collecting portion 61, negative electrode second current collecting portion 62) inside the exterior body 12. The negative electrode terminal 40 is insulated from the sealing plate 14 by the insulating member 70 and the gasket 90. The negative electrode terminal 40 exposed to the outside of the battery case 10 through the terminal insertion hole 19 is connected to the negative electrode external conductive member 42 outside the sealing plate 14. An external insulating member 92 is interposed between the above-mentioned external conductive members (positive electrode external conductive member 32, negative electrode external conductive member 42) and the outer surface of the sealing plate 14. This external insulating member 92 can insulate the external conductive members 32, 42 from the sealing plate 14.

[0043] Next, the insulating member 70 according to this embodiment will be described in detail. As shown in Fig. 2, the insulating member 70 according to this embodiment is disposed between the sealing plate 14 and a positive electrode current collector (specifically, the positive electrode first current collector 51) and a negative electrode current collector (specifically, the negative electrode first current collector 61). The material constituting the insulating member 70 is not particularly limited as long as the effects of the technology disclosed herein are exhibited. The material constituting the insulating member 70 is preferably a resin material that has resistance to the electrolyte solution used, electrical insulation properties, and is elastically deformable. Examples of the material include polyolefin resins such as polypropylene (PP), fluorinated resins such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), and polyphenylene sulfide (PPS).

[0044] The insulating member 70 according to this embodiment is fixed to the sealing plate 14 by fitting. FIG. 11 is a schematic perspective view illustrating the insulating member 70, and FIG. 12 is an upside-down perspective view of the insulating member 70 of FIG. 11. As shown in FIG. 11, the insulating member 70 includes a rectangular wide surface 70a, a pair of side walls 70b, and a pair of side walls 70c. Also, as shown in FIG. 11, a plurality of protrusions 5 used for fitting are present on the surface of the wide surface 70a. The material constituting the protrusions 5 is not particularly limited as long as the effects of the technology disclosed herein are exhibited. For example, the resin materials listed in the description of the insulating member 70 can be used. The material constituting the protrusions 5 may be the same as or different from the material constituting the insulating member 70. In this embodiment, the shape of the protrusions 5 is cylindrical, but is not limited thereto and can be various shapes, such as a square or a rectangular parallelepiped. The number of protrusions 5 can be appropriately changed depending on the usage mode. In this embodiment, the insulating member 70 is fixed to the sealing plate 14 by fitting, but the insulating member disclosed herein may be fixed to the sealing plate by, for example, adhering with an adhesive or the like, or may be fixed by combining fitting and adhesion as described above.

[0045] FIG. 10 is a schematic diagram illustrating a sealing plate 14 according to this embodiment. As shown in FIG. 10, recesses 4 corresponding to the protrusions 5 are present on the surface of the sealing plate 14. In this case, the recesses 4 are provided so as not to penetrate to the opposite surface. The sealing plate 14 and the insulating member 70 are fixed by fitting the recesses 4 of the sealing plate 14 with the protrusions 5 of the insulating member 70. Here, FIG. 8 is a perspective view schematically illustrating the sealing plate 14 to which the positive electrode terminal 30, the negative electrode terminal 40, the positive electrode first current collecting portion 51, the negative electrode first current collecting portion 61, and the insulating member 70 are attached, and FIG. 9 is a perspective view of the sealing plate 14 shown in FIG. 8 turned upside down.

[0046] Next, the insulating sheet 29 according to this embodiment will be described in detail. Fig. 13 is a schematic development view for explaining the insulating sheet 29. Fig. 14 is a schematic perspective view in which the insulating sheet 29 is arranged so as to cover the electrode body group 20 of Fig. 5. As shown in FIG. 13, the insulating sheet 29 according to this embodiment includes a sheet bottom wall 29a, a pair of sheet first side walls 29b extending from the sheet bottom wall 29a and facing each other, and a pair of sheet second side walls 29c extending from the sheet bottom wall 29a and facing each other (FIG. 13 shows the sheet second side wall forming portions 29c' before the sheet second side walls are constructed). The sheet bottom wall 29a is rectangular here. Also, as shown in FIGS. 4 and 13, the sheet second side walls 29c are composed of a pair of sheet second side wall forming portions 29c' and can be constructed by joining the ends of the sheet second side wall forming portions 29c' together by thermal welding, tape application, or the like. For example, the insulating sheets 129, 429, 529, and 629 described below can also be constructed by referring to the construction method of the insulating sheet 29. 4, in this embodiment, the sheet second sidewall forming portions 29c' are joined together without any gaps in the Y direction, but this is not limited thereto, and for example, a gap may exist. If a gap exists, the size of the gap is not particularly limited as long as the effects of the technology disclosed herein are achieved. The size of the gap is generally 3 mm or less, and can be, for example, 2 mm or less or 1 mm or less.

[0047] Furthermore, in the present embodiment, the inner surface of the sheet second side wall 29c (more specifically, the sheet second side wall forming portion 29c') is in contact with the outer surface of the positive electrode second current collector 52, but this is not limiting. A gap may exist between the inner surface of the sheet second side wall 29c and the outer surface of the positive electrode second current collector 52. Note that in the present embodiment, the area of ​​the sheet second side wall forming portion 29c' is smaller than the area of ​​the sheet second side wall 29c, but this is not limiting. The area of ​​the sheet second side wall forming portion 29c' may be the same as the area of ​​the sheet second side wall 29c. For example, the former case is preferable because it allows adjustment of the restraining force on the electrode body when joining the sheet second side wall forming portions together.

[0048] As shown in FIG. 14 , in this embodiment, the length P (see FIG. 11 ) of the short side of the wide surface 70 a of the insulating member 70 is the same as the thickness Q (see FIG. 5 ) of the electrode assembly (here, the electrode assembly group 20), but this is not limited thereto. For example, from the viewpoint of more firmly fixing the insulating sheet 29 and the electrode assembly group 20, it is more preferable that the length P of the short side is smaller than the thickness Q of the electrode assembly. In this way, when the length P of the short side is smaller than the thickness Q of the electrode assembly, the insulating sheet 29 has a tapered shape on the sealing plate side. This can more effectively prevent, for example, the electrode assembly group 20 from being displaced from its predetermined position due to an external force applied in the longitudinal direction Y of the electrode assembly group 20, and therefore can more effectively prevent damage to the electrode tab groups (here, the positive electrode tab group 23 and the negative electrode tab group 25). Furthermore, in this case, the ratio of the length P of the short side to the thickness Q of the electrode assembly (short side length P / thickness Q of the electrode assembly) can be set to approximately 0.5 to 0.9 (e.g., within a range of 0.7 to 0.8).

[0049] In this embodiment, the length R (see FIG. 13 ) of the short side of the sheet bottom wall 29a of the insulating sheet 29 is the same as the thickness Q (see FIG. 5 ) of the electrode assembly (here, the electrode assembly group 20), but is not limited thereto. For example, from the viewpoint of more firmly fixing the insulating sheet 29 and the electrode assembly group 20, it is more preferable that the length R of the short side is smaller than the thickness Q of the electrode assembly. In this way, when the length R of the short side is smaller than the thickness Q of the electrode assembly, the bottom wall side of the insulating sheet has a tapered shape. This can more effectively prevent the electrode assembly group 20 from being displaced from its predetermined position due to, for example, an external force applied in the longitudinal direction Y of the electrode assembly group 20, and therefore more effectively prevent damage to the electrode tab groups (here, the positive electrode tab group 23 and the negative electrode tab group 25). In the above-described case, the ratio of the length R of the short side to the thickness Q of the electrode assembly (the length R of the short side / the thickness Q of the electrode assembly) can be set to a range of approximately 0.5 to 0.9 (e.g., 0.7 to 0.8).

[0050] Note that "thickness of electrode body" refers to the total thickness of the electrode bodies when, for example, multiple electrode bodies are present in the battery case (see Q in FIG. 5), and refers to the thickness of one electrode body when, for example, one electrode body is present. Furthermore, the insulating sheet disclosed herein may have a tapered shape on the sealing plate side and a tapered shape on the bottom wall side, for example.

[0051] In this embodiment, the insulating member 70 and the insulating sheet 29 are joined via a joint 1 and a joint 1′. Furthermore, in this embodiment, at least a portion of the joint 1 between the insulating member 70 and the insulating sheet 29 is located within a range of (¼)L or less from the center (center line CL) of the electrode body 20a in the direction along the first side wall 12b (i.e., the Y direction in FIG. 2), where L is the length of the electrode body 20a in the direction along the first side wall 12b (see FIG. 14). This aspect is preferable because it allows the insulating sheet 29 to be fixed at a position close to the center of the electrode body 20a and can effectively prevent the insulating sheet 29 from bending. It is more preferable that the joint 1 is located within a range of (⅕)L or less from the center (center line CL) of the electrode body 20a in the planar direction, and even more preferable that it is located within a range of (⅙)L or less from the center (center line CL) of the electrode body 20a in the planar direction. In this embodiment, the insulating member 70 and the insulating sheet 29 are joined via the joints 1 and 1', but they may also be joined to the sealing plate by, for example, heat welding or ultrasonic welding. Alternatively, they may be fixed by forming a recess or protrusion at a predetermined position on the insulating member and fitting it into a protrusion or recess formed on the insulating sheet.

[0052] In this embodiment, the bonding portions 1 and 1' are adhesive layers. The material for forming such adhesive layers is not particularly limited as long as the effects of the technology disclosed herein are exhibited. Examples of such materials include fluororesins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE); acrylic resins; polyamide resins; polyimide resins; and polyurethane resins. Furthermore, from the viewpoint of simplifying the bonding of the insulating sheet 29 to the insulating member 70, various adhesives (e.g., pressure-sensitive adhesives) can be preferably used as the material. Examples of such adhesives include acrylic adhesives, rubber adhesives, silicone adhesives, and urethane adhesives. Alternatively, the resin material may be a photocurable resin (e.g., a photocurable acrylic resin) or a thermosetting resin (e.g., a thermosetting acrylic resin). In this embodiment, the bonding portions 1 and 1' are formed on the insulating sheet 29, but the present invention is not limited thereto. For example, the bonding portions may be formed on the insulating member side. The above-mentioned materials can also be used for the bonding portions 101, 101', 101'', 201, 301, 401, 401', 501, and 501', which will be described later.

[0053] In this embodiment, the joints 1 are provided intermittently, but this is not limiting and, for example, they may be provided continuously. The area of ​​the region where the joints 1 and 1' are formed is not particularly limited as long as the effects of the technology disclosed herein are achieved. While not limited thereto, the area of ​​the region where the joints 1 are formed in one of the pair of sheet first side walls 29b (if there are multiple joints 1, the total area) can be approximately 20 to 90% (e.g., 40 to 60%) of the area of ​​one side wall 70b of the insulating member 70. The same applies to the other sheet first side wall. Furthermore, the area of ​​the region where the joints 1' are formed in one of the two sheet second side wall forming portions 29c' constituting the sheet second side wall 29c (if there are multiple joints 1', the total area) can be approximately 20 to 90% (e.g., 40 to 60%) of the area of ​​one side wall 70c of the insulating member 70. The same applies to the second side wall forming portion of the other sheet. The thickness of the joint 1 and the joint 1' can be determined appropriately depending on the usage form. The joints 101, 201, 301, 401, and 501 described below can have the same configuration as the joint 101. The joints 101', 401', and 501' described below can have the same configuration as the joint 101'.

[0054] <Method of manufacturing the battery 100> The manufacturing method of the battery 100 is characterized by the use of the insulating member 70 and insulating sheet 29 described above. Other manufacturing processes may be similar to conventional methods. The battery 100 can be manufactured by preparing the insulating member 70 and insulating sheet 29, as well as the battery case 10 (exterior body 12 and sealing plate 14), the electrode assembly 20 (electrode assemblies 20a, 20b, 20c), the electrolyte, the positive terminal 30, the negative terminal 40, the positive current collector 50 (first positive current collector 51 and second positive current collector 52), and the negative current collector 60 (first negative current collector 61 and second negative current collector 62). For example, the manufacturing method disclosed herein may further include other processes at any stage.

[0055] 8 and 9 is produced. Specifically, first, the positive electrode terminal 30, the positive electrode first current collecting portion 51, the negative electrode terminal 40, the negative electrode first current collecting portion 61, and the insulating member 70 are attached to the sealing plate 14.

[0056] The positive electrode terminal 30, the negative electrode terminal 40, the positive electrode first current collecting portion 51, the negative electrode first current collecting portion 61, and the insulating member 70 are fixed to the sealing plate 14 by, for example, crimping (riveting). The crimping is performed by sandwiching a gasket 90 between the outer surface of the sealing plate 14 and the positive electrode terminal 30 and the negative electrode terminal 40, respectively, and sandwiching the insulating member 70 between the inner surface of the sealing plate 14 and the positive electrode first current collecting portion 51 and the negative electrode first current collecting portion 61. At this time, the recessed portion 4 of the sealing plate 14 is fitted into the protruding portion 5 of the insulating member 70, thereby fixing the sealing plate 14 and the insulating member 70 together. The material of the gasket 90 may be the same as that of the insulating member 70. The positive electrode terminal 30 before crimping is inserted from above the sealing plate 14, sequentially through the through hole of the gasket 90, the terminal lead-out hole 18 of the sealing plate 14, the through hole of the insulating member 70, and the through hole 51h of the positive electrode first current collecting portion 51, so as to protrude below the sealing plate 14. The negative electrode terminal 40 before crimping is inserted from above the sealing plate 14, sequentially through the through hole of the gasket 90, the terminal lead-out hole 19 of the sealing plate 14, the through hole of the insulating member 70, and the through hole 61h of the negative electrode first current collecting portion 61, so as to protrude below the sealing plate 14. The portions of the positive electrode terminal 30 and the negative electrode terminal 40 that protrude below the sealing plate 14 are then crimped so that a compressive force is applied in the up-down direction Z. As a result, a crimped portion 30c is formed at the tip end (lower end in FIG. 2) of the positive electrode terminal 30, and a crimped portion 40c is formed at the tip end (lower end in FIG. 2) of the negative electrode terminal 40.

[0057] By such crimping, the gasket 90, sealing plate 14, positive electrode first current collecting portion 51, negative electrode first current collecting portion 61, and insulating member 70 are integrally fixed to the sealing plate 14, and the terminal holes 18 and 19 are sealed. Note that crimped portion 30c and crimped portion 40c may be welded to the positive electrode first current collecting portion 51 and the negative electrode first current collecting portion 61, respectively. This can further improve the reliability of conduction.

[0058] Next, the positive electrode external conductive member 32 and the negative electrode external conductive member 42 are attached to the outer surface of the sealing plate 14 via the external insulating member 92. The material of the external insulating member 92 may be the same as that of the positive electrode insulating member 70. The timing of attaching the positive electrode external conductive member 32 and the negative electrode external conductive member 42 may be after the insertion step (for example, after the liquid injection hole 15 is sealed).

[0059] In the second mounting step, a second combined body as shown in FIG. 5 is produced using the first combined body produced in the first mounting step. That is, an electrode body group 20 is produced that is integrated with a sealing plate 14. Specifically, as shown in FIG. 6, three electrode bodies 20a, each having a positive electrode second current collecting portion 52 and a negative electrode second current collecting portion 62 attached thereto, are first prepared and arranged side by side in the short side direction X as electrode bodies 20a, 20b, and 20c. At this time, the electrode bodies 20a, 20b, and 20c may all be arranged in parallel such that the positive electrode second current collecting portion 52 is arranged on one side in the long side direction Y (the left side in FIG. 5) and the negative electrode second current collecting portion 62 is arranged on the other side in the long side direction Y (the right side in FIG. 5).

[0060] Next, as shown in FIG. 4, with the multiple positive electrode tabs 22t bent, the positive electrode first current collecting portion 51 fixed to the sealing plate 14 is joined to each of the positive electrode second current collecting portions 52 of the electrode assemblies 20a, 20b, and 20c. Also, with the multiple negative electrode tabs 24t bent, the negative electrode first current collecting portion 61 fixed to the sealing plate 14 is joined to each of the negative electrode second current collecting portions 62 of the electrode assemblies 20a, 20b, and 20c. Examples of joining methods that can be used include ultrasonic welding, resistance welding, and laser welding. In particular, welding using high-energy rays such as lasers is preferably used.

[0061] Next, in the insulating sheet bonding step, the insulating sheet 29 is bonded to the insulating member 70 provided on the sealing plate 14. Specifically, first, the insulating sheet 29 is constructed using a resin sheet as shown in FIG. 13. Then, the constructed insulating sheet 29 is bonded to a predetermined position on the insulating member 70 via the bonding portion 1 and the bonding portion 1′. In this manner, the insulating sheet 29 and the insulating member 70 can be bonded. Note that in this embodiment, the electrode assembly 20 is covered with a pre-constructed insulating sheet 29, but this is not limiting. For example, the insulating sheet may be constructed by covering the electrode assembly with the insulating sheet and then bonding the ends of the second sidewall-forming portions of the sheet together.

[0062] In the insertion step, the second combined body produced in the second attachment step is housed in the internal space of the exterior body 12. Fig. 15 is a schematic cross-sectional view illustrating the insertion step. Specifically, the electrode assembly 20 covered with an insulating sheet 29 is inserted into the exterior body 12. If the weight of the electrode assembly 20 is heavy, approximately 1 kg or more, for example 1.5 kg or more, or even 2 to 3 kg, it is advisable to insert the electrode assembly 20 into the exterior body 12 by arranging the long side wall 12b of the exterior body 12 so that it intersects with the direction of gravity (the exterior body 12 is oriented horizontally), as shown in Fig. 15.

[0063] In the sealing step, a sealing plate 14 is joined to the edge of the opening 12h of the exterior body 12 to seal the opening 12h. The sealing step can be performed simultaneously with or after the insertion step. In the sealing step, the exterior body 12 and the sealing plate 14 are preferably welded together. The welding of the exterior body 12 and the sealing plate 14 can be performed by, for example, laser welding. Thereafter, an electrolyte is injected through the liquid inlet 15, and the liquid inlet 15 is closed with a sealing member 16 to hermetically seal the battery 100. In this manner, the battery 100 can be manufactured.

[0064] Battery 100 can be used for a variety of purposes, but is preferably used in applications where external forces such as vibrations and shocks may be applied during use, such as a power source (driving power source) for a motor mounted on a moving body (typically a vehicle such as a passenger car or truck). The type of vehicle is not particularly limited, but examples include plug-in hybrid vehicles (PHVs), hybrid vehicles (HVs), and electric vehicles (EVs). Battery 100 can also be preferably used as a battery pack in which multiple batteries 100 are arranged in a predetermined arrangement direction and a load is applied from the arrangement direction using a restraining mechanism.

[0065] <Other embodiments> Although several embodiments of the present invention have been described above, the above embodiments are merely examples. The present invention can be implemented in various other forms. The present invention can be implemented based on the contents disclosed in this specification and the common general technical knowledge in the relevant field. The technology described in the claims includes various modifications and alterations of the above-exemplified embodiments. For example, it is possible to replace part of the above-described embodiments with other modified embodiments, and it is also possible to add other modified embodiments to the above-described embodiments. Furthermore, if a technical feature is not described as essential, it may be deleted as appropriate.

[0066] For example, in the above embodiment, the insulating sheet 29 includes the bottom wall 29a, the pair of first side walls 29b, and the pair of second side walls 29c, but is not limited thereto. The insulating sheet disclosed herein may include only the bottom wall 29a and the pair of first side walls 29b, for example.

[0067] For example, in the above embodiment, the joints 1 and 1' are rectangular, but are not limited thereto. The shapes of the joints 1 and 1' may be various shapes, such as circular, elliptical, or triangular, and may also be combinations of these shapes. Also, for example, in the above embodiment, the joints 101' are formed in both of the two sheet second sidewall forming portions 29c' that make up the sheet second sidewall 29c, but are not limited thereto. The joints 101' may be formed in only one of the two sheet second sidewall forming portions 29c'.

[0068] FIG. 16 is a schematic development view for explaining an insulating sheet 129 according to the second embodiment. As shown in FIG. 16, in addition to the joints 101 and 101′, a joint 101″ is formed on a first sheet side wall 129b of the insulating sheet 129. With this configuration, at least a portion of the insulating sheet 129 can be joined to the electrode bodies (here, the electrode bodies 20a and 20c). In this case, the insulating sheet 129 and the electrode body group 20 are more firmly fixed, and therefore, it is possible to preferably prevent the electrode body group 20 from being displaced from a predetermined arrangement position due to, for example, an external force applied in the longitudinal direction Y of the electrode body group 20. This makes it possible to preferably prevent damage to the electrode tab groups (here, the positive electrode tab group 23 and the negative electrode tab group 25).

[0069] In the second embodiment, the insulating sheet and the electrode assembly are joined via the joint 101'', but this is not limiting. For example, if the outermost separator of the electrode assembly has an adhesive layer, the insulating sheet and the electrode assembly can also be fixed via this adhesive layer.

[0070] FIG. 17 is a schematic diagram illustrating a development view of an insulating sheet 229 according to the third embodiment and a fixing member. As shown in FIG. 17, the insulating sheet 229 includes a sheet bottom wall 229a and a pair of sheet first side walls 229b that extend from the sheet bottom wall 229a and face each other. In the third embodiment, a fixing member 202 is disposed from one of the pair of sheet first side walls 229b to the other. With this configuration, the fixing member 202 can be used to separately fix a current collecting region S (see FIG. 2) where the positive electrode tab group 23 or the negative electrode tab group 25 is present and a non-current collecting region T (see FIG. 2) where the positive electrode tab group 23 or the negative electrode tab group 25 is not present. In this case, for example, the binding force of the fixing member 202 can be weakened in the current collecting region S where the positive electrode tab group 23 or the negative electrode tab group 25 is present, and the binding force of the fixing member 202 can be strengthened in the non-current collecting region T where the positive electrode tab group 23 or the negative electrode tab group 25 is not present, so that the insulating sheet 229 and the electrode body group 20 can be firmly fixed while suitably preventing damage to the positive electrode tab group 23 and the negative electrode tab group 25. This makes it possible to suitably prevent damage to the electrode tab groups (here, the positive electrode tab group 23 and the negative electrode tab group 25).

[0071] The fixing member 202 preferably includes, for example, a substrate and an adhesive layer formed on the substrate. Examples of the substrate include polyethylene (PE), polypropylene (PP), polyester, nylon, vinyl chloride, Teflon (registered trademark), polyimide, Kapton (registered trademark), polyphenylene sulfide, and polyethylene naphthalate. The thickness of the substrate is not particularly limited as long as the effects of the technology disclosed herein are exhibited, and may be approximately 5 μm to 100 μm, for example, 10 μm to 50 μm. Examples of materials constituting the adhesive layer include acrylic adhesives, silicone adhesives, and rubber adhesives. The adhesive layer preferably has adhesiveness at room temperature (typically, about 20°C). The thickness of the adhesive layer is not particularly limited as long as the effects of the technology disclosed herein are exhibited, and may be approximately 5 μm to 100 μm, for example, 5 μm to 20 μm. Fixing members such as fixing member 302 may also have a similar configuration.

[0072] 18 is a development view of an insulating sheet 329 according to a fourth embodiment and a schematic diagram for explaining a fixing member. As shown in FIG. 18, the insulating sheet 329 includes a sheet bottom wall 329a, a pair of sheet first side walls 329b extending from the sheet bottom wall 329a and facing each other, and a pair of sheet second side walls 329c extending from the sheet bottom wall 329a and facing each other. In the fourth embodiment, a fixing member 302 is disposed from one of the pair of sheet first side walls 329b to the other sheet first side wall. This configuration can achieve the effects described in the third embodiment.

[0073] In the first and second embodiments, fixing members as described in the third and fourth embodiments can also be arranged. This configuration can achieve the effects described in the third embodiment. While the second side wall portion of the sheet is covered by two fixing members in the above example, the present invention is not limited to this. For example, the second side wall portion may be covered by one fixing member or three or more fixing members. When two or more fixing members are used, the fixing members may be the same size or different sizes.

[0074] FIG. 19 is a schematic development view for explaining an insulating sheet 429 according to a fifth embodiment. As shown in FIG. 19, the insulating sheet 429 includes a sheet bottom wall 429a, a pair of sheet first side walls 429b, and a pair of sheet second side walls (FIG. 19 shows the state in which the sheet second side walls are not yet constructed, i.e., the sheet second side wall forming portions 429c', 429c''). Each sheet second side wall is separated into a current collecting region formed by the pair of sheet second side wall forming portions 429c' and a non-current collecting region formed by the pair of sheet second side wall forming portions 429c''. With this configuration, the binding force can be adjusted between the current collecting region and the non-current collecting region. This makes it possible to firmly fix the insulating sheet 429 and the electrode body group 20 while suitably preventing damage to the positive electrode tab group 23 and the negative electrode tab group 25, thereby suitably preventing damage to the electrode tab groups (here, the positive electrode tab group 23 and the negative electrode tab group 25).

[0075] FIG. 20 is a schematic development view for explaining an insulating sheet 529 according to a sixth embodiment. As shown in FIG. 20, the insulating sheet 529 includes a sheet bottom wall 529a, a pair of sheet first side walls 529b, and a pair of sheet second side walls (FIG. 20 shows the state in which the sheet second side walls are not yet constructed, i.e., the sheet second side wall forming portions 529c' and 529c''). Each of the sheet second side walls is separated into a current collecting region formed by the pair of sheet second side wall forming portions 529c' and a non-current collecting region formed by the pair of sheet second side wall forming portions 529c''. This configuration allows adjustment of the binding force between the current collecting region and the non-current collecting region. Also, as shown in FIG. 20, the valley fold line l1 in 529c' and the valley fold line l2 in 529c'' are formed to be offset from each other. This makes it possible to firmly fix the insulating sheet 529 and the electrode body group 20 while suitably preventing damage to the electrode tab groups (here, the positive electrode tab group 23 and the negative electrode tab group 25).

[0076] In the fifth and sixth embodiments, fixing members as described in the third and fourth embodiments can also be arranged. In the fifth embodiment, the pair of sheet second sidewall forming portions 429c' or the pair of sheet second sidewall forming portions 429c'' that form the sheet second sidewalls of the insulating sheet 429 can be eliminated. In this case, fixing members can be arranged in the portions where the sheet second sidewall forming portions have been eliminated. The same applies to the sixth embodiment.

[0077] For example, in the above first to sixth embodiments, the electrode assembly 20 is covered with an insulating sheet, but this is not limited to this, and for example, each of the electrode bodies 20a, 20b, and 20c that make up the electrode assembly 20 can also be individually covered with an insulating sheet.

[0078] Furthermore, the shape and configuration of the insulating member are not particularly limited as long as the effects of the technology disclosed herein are exhibited. Fig. 21 is a schematic diagram for explaining a battery 200 according to another embodiment. As shown in Fig. 21, the insulating member may be separated into portions 270a, 270b, and 270c, for example.

[0079] FIG. 22 is a schematic diagram for explaining a battery 300 according to another embodiment. As shown in FIG. 22, a movement-restricting member A may be disposed between the second sheet side wall of the insulating sheet 29 and the electrode assembly group 20. With this configuration, it is possible to more effectively prevent the electrode assembly group 20 from being displaced from its predetermined position due to, for example, an external force applied in the longitudinal direction Y of the electrode assembly group 20. This makes it possible to more effectively prevent damage to the electrode tab groups (here, the positive electrode tab group 23 and the negative electrode tab group 25). The material constituting the movement-restricting member A is not particularly limited as long as the effects of the technology disclosed herein are exhibited, and it may be, for example, the material constituting the insulating member 70. Furthermore, for example, such a fixing member may be disposed in the second to sixth embodiments as well. [Explanation of symbols]

[0080] 1, 101, 201, 301, 401, 501 joint 10 Battery case 12 Exterior body 14 Sealing plate 20 Electrode group 20a, 20b, 20c electrode body 23 Positive electrode tab group (electrode tab group) 25 Negative electrode tab group (electrode tab group) 29, 129, 229, 329, 429, 529 Insulation sheet 30 Positive terminal (terminal) 40 Negative terminal (terminal) 50 Positive electrode current collector 51 Positive electrode first current collecting part (current collecting part) 52 Positive electrode second current collecting part 60 Negative electrode current collector 61 Negative electrode first current collecting part (current collecting part) 62 Negative electrode second current collecting part 70, 270a, 270b, 270c insulating members 90 Gasket 100, 200, 300 batteries

Claims

1. A battery comprising one or more electrode assemblies including a positive electrode and a negative electrode, and a battery case that houses the electrode assemblies, The battery case is an exterior body having a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall; a sealing plate that seals the opening; It is equipped with a positive electrode terminal and a negative electrode terminal are attached to the sealing plate; The electrode body is a group of positive electrode tabs protruding from an end portion facing one of the pair of second side walls; a group of negative electrode tabs protruding from an end portion of the pair of second side walls that faces the other second side wall; It is equipped with the positive electrode tab group and the positive electrode terminal are electrically connected via a positive electrode current collecting portion, the positive electrode tab group is joined to the positive electrode current collecting portion in a curved state such that a portion of the positive electrode tab group is disposed along the one second side wall, the negative electrode tab group and the negative electrode terminal are electrically connected via a negative electrode current collecting portion, the negative electrode tab group is joined to the negative electrode current collecting portion in a curved state such that a portion of the negative electrode tab group is disposed along the other second side wall, The sealing plate is provided with an insulating member, An insulating sheet is joined to the insulating member so as to cover the electrode body, and the insulating sheet includes at least a seat bottom wall, a pair of seat first side walls extending from the seat bottom wall and facing each other, and a pair of seat second side walls extending from the seat bottom wall and facing each other, the seat first side walls facing the first side walls, and the seat second side walls facing the second side walls, the positive electrode current collecting portion has a first region disposed between the sealing plate and the electrode body, and a second region bent from an end of the first region and extending in a direction away from the sealing plate, The positive electrode terminal is directly connected to the first region, the second region is disposed between one of the pair of second side walls and the electrode body, the negative electrode current collecting portion has a third region disposed between the sealing plate and the electrode body, and a fourth region bent from an end of the third region and extending in a direction away from the sealing plate, The negative electrode terminal is directly connected to the third region, the fourth region is disposed between the other second side wall of the pair of second side walls and the electrode body, a movement restricting member that restricts positional displacement of the electrode body toward the second side wall is disposed between the positive electrode tab group and the sheet bottom wall and / or between the negative electrode tab group and the sheet bottom wall, and between the sheet second side wall and the electrode body; The battery, wherein the movement restricting member is a separate part from the insulating sheet.

2. a first movement restricting member is disposed between the positive electrode tab group and the seat bottom wall; a second movement restricting member is disposed between the negative electrode tab group and the sheet bottom wall; the first movement restricting member and the second movement restricting member are separate parts from the insulating sheet; The battery of claim 1 .

3. In a direction perpendicular to the second side wall, the thickness of the movement restricting member is greater than the thickness of the second side wall of the sheet. The battery of claim 1 .

4. The sheet second side wall is joined to the insulating member. The battery of claim 1 .

Images