Energy storage cell

Abstract

The present invention provides a power storage cell that can prevent damage to the electrode tabs connected to the current collector plate. [Solution] The energy storage cell 100 includes an electrode body 10 including a first electrode 10A, a first connecting member 50A positioned opposite the electrode body 10, and a first tab 90A connecting the first electrode 10A and the first connecting member 50A. The first connecting member 50A includes a lower surface 51a facing the electrode body 10 and an upper surface 51b positioned on the opposite side of the lower surface 51a. The first tab 90A is connected to the upper surface 51b.

Description

Technical Field

[0001] The present disclosure relates to a storage battery cell.

Background Art

[0002] Japanese Patent Publication No. 2023-527677 (Patent Document 1) discloses a battery cell including an electrode component and a current collector member. The electrode component includes a first active material portion and a plurality of first non-active material portions (tabs) protruding from the first active material portion. The first non-active material portion is welded to the surface of the current collector member on the side of the first active material portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1 described above, as described above, the first non-active material portion (electrode tab) is welded to the surface of the current collector member (current collector plate) on the side of the first active material portion (electrode body). Therefore, the first non-active material portion is bent in the narrow space between the current collector member and the first active material portion. As a result, excessive bending stress is applied to the first non-active material portion, and the first non-active material portion may be damaged.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a storage battery cell capable of suppressing breakage of an electrode tab connected to a current collector plate.

Means for Solving the Problems

[0006] A power storage cell according to one aspect of the present disclosure comprises an electrode body including an electrode sheet, a current collector plate positioned opposite the electrode body, and an electrode tab connecting the electrode sheet and the current collector. The current collector plate includes a first surface facing the electrode body and a second surface positioned opposite the first surface. The electrode tab is connected to the second surface. [Effects of the Invention]

[0007] According to this disclosure, damage to the electrode tabs connected to the current collector plate can be suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the configuration of the energy storage device and frame members according to this embodiment. [Figure 2] This is a perspective view showing the configuration of the energy storage cell according to this embodiment. [Figure 3] This is an exploded perspective view showing the configuration of the energy storage cell according to this embodiment. [Figure 4] This is a cross-sectional view of the electrode body. [Figure 5] This is a partially enlarged cross-sectional view showing the configuration of the first electrode and the first tab. [Figure 6] This is a schematic cross-sectional view showing the configuration of the energy storage cell and the first connecting member. [Figure 7] This is a partially enlarged view of the vicinity of the first connecting member in Figure 6. [Figure 8] This is a cross-sectional view showing the configuration of the first tab according to a first modified example of this embodiment. [Figure 9] This is a cross-sectional view showing the configuration of the first tab according to a second modification of this embodiment. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same number.

[0010] Figure 1 is a perspective view showing the configuration of an energy storage device 1 including an energy storage cell 100 in an embodiment of the present disclosure. The energy storage device 1 is mounted, for example, on a vehicle (not shown). Examples of vehicles include hybrid electric vehicles, plug-in hybrid electric vehicles, and battery electric vehicles. The energy storage device 1 may also be installed in electrical equipment other than electric vehicles (for example, a stationary energy storage device).

[0011] In this specification, the X, Y, and Z directions are mutually orthogonal directions. For example, the X and Y directions may be the front-to-back and left-to-right directions, respectively, when the energy storage device 1 is mounted on an electric vehicle. The Z direction may also be the up-and-down direction. Specifically, the Z1 and Z2 directions may be upward and downward, respectively.

[0012] The energy storage device 1 is attached to a frame member 2 located at the bottom of the vehicle. The frame member 2 is formed in a roughly rectangular cylindrical shape that surrounds the energy storage device 1.

[0013] The energy storage device 1 comprises multiple energy storage stacks 3. Each energy storage stack 3 is formed in the shape of a rectangular parallelepiped, elongated in the Y direction. The multiple energy storage stacks 3 are arranged in a line along the X direction. Each energy storage stack 3 contains multiple energy storage cells 100 arranged in the Y direction. Note that in Figure 1, for simplification, only two energy storage stacks 3 are shown, and only three energy storage cells 100 in each energy storage stack 3 are shown.

[0014] Figure 2 is a perspective view showing the energy storage cell 100 according to this embodiment. As shown in Figure 2, the energy storage cell 100 is a so-called prismatic battery. The energy storage cell 100 is a secondary battery configured to be chargeable and dischargeable. The energy storage cell 100 may be a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. The energy storage cell 100 can be used, for example, as a cell included in an energy storage module mounted on an electric vehicle.

[0015] The storage battery cell 100 includes an electrode body 10, a case 20, a first external terminal 30A, a second external terminal 30B, a first terminal support portion 40A, and a second terminal support portion 40B. In FIG. 2, the electrode body 10 is schematically shown by a dashed line.

[0016] The case 20 has conductivity. The conductive portion of the case 20 is made of a metal such as aluminum or the like. The case 20 houses the electrode body 10. The case 20 also houses an electrolytic solution (not shown).

[0017] The case 20 includes a case body 21 and a lid 22. The case body 21 includes a bottom wall 210 and a peripheral wall 211 standing up from the bottom wall 210.

[0018] The lid 22 includes a lid body 220 and an insulating cover 221. The lid body 220 is joined to the peripheral wall 211 by welding or the like so as to close the opening of the peripheral wall 211.

[0019] The first external terminal 30A and the second external terminal 30B are provided so as to be exposed to the outside in the storage battery cell 100. In this embodiment, the first external terminal 30A is a positive electrode terminal and the second external terminal 30B is a negative electrode terminal. The first external terminal 30A and the second external terminal 30B are arranged side by side in the X direction.

[0020] The first terminal support portion 40A is locked to the lid body 220. The first terminal support portion​​​Figure 3 is an exploded perspective view of the energy storage cell 100 according to this embodiment. The energy storage cell 100 further comprises a first connecting member 50A, a second connecting member 50B, a first sealing ring 60A, a second sealing ring 60B, an insulating member 70, and a fuse protection unit 80. The first connecting member 50A is an example of the "current collector plate" of this disclosure.

[0022] The bottom wall 210 includes a bottom body 212, an outer protective film 213, and an inner protective film 214. The peripheral wall 211 rises from the bottom body 212. A pressure relief valve SV is provided in the bottom body 212. The outer protective film 213 covers the pressure relief valve SV from the outside. The inner protective film 214 covers the pressure relief valve SV from the inside. The bottom body 212 and the pressure relief valve SV are made of a metal such as aluminum.

[0023] An opening is formed at the upper end of the peripheral wall 211. The peripheral wall 211 has a substantially rectangular outer shape when viewed from the direction of the opening. The opening and the bottom wall 210 are aligned in the Z direction. The opening is located on the Z1 side of the bottom wall 210. The Z direction may be the height direction or vertical direction of the energy storage cell 100. The peripheral wall 211 is made of a metal such as aluminum.

[0024] The lid 22 further includes a sealing plug 222 and a plug cover 223. The lid body 220 has a first connecting hole 224A, a second connecting hole 224B, and an electrolyte injection hole 225. The electrolyte injection hole 225 is a through hole for injecting electrolyte into the case body 21 during the manufacturing process of the energy storage cell 100.

[0025] The sealing plug 222 seals the injection hole 225. The plug cover 223 covers the injection hole 225 and the sealing plug 222. The insulating cover 221 covers the injection hole 225, the sealing plug 222, and the plug cover 223.

[0026] The first connecting member 50A and the second connecting member 50B are conductive. At least a portion of the first connecting member 50A and the second connecting member 50B are located inside the case 20. Each of the first connecting member 50A and the second connecting member 50B is positioned opposite the electrode body 10 in the Z direction. Each of the first connecting member 50A and the second connecting member 50B is positioned on the Z1 side of the electrode body 10.

[0027] The first external terminal 30A or the first connecting member 50A is inserted through the first connecting hole 224A. The first external terminal 30A and the first connecting member 50A are joined to each other. The first connecting member 50A is joined to the electrode body 10. As a result, the first external terminal 30A is electrically connected to the electrode body 10.

[0028] The second external terminal 30B or the second connecting member 50B is inserted through the second connecting hole 224B. The second external terminal 30B and the second connecting member 50B are joined to each other. The second connecting member 50B is joined to the electrode body 10. As a result, the second external terminal 30B is electrically connected to the electrode body 10.

[0029] The first seal ring 60A is provided along the first connecting hole 224A. The first seal ring 60A is provided in the gap between the lid body 220 and the first external terminal 30A, and seals this gap. The second seal ring 60B is provided along the second connecting hole 224B. The second seal ring 60B is provided in the gap between the lid body 220 and the second external terminal 30B, and seals this gap. The first seal ring 60A and the second seal ring 60B have electrical insulating properties.

[0030] The first terminal support portion 40A includes a first locking ring 41A and a first covering ring 42A. The first locking ring 41A extends in an annular shape to surround the first connecting hole 224A and is directly locked to the lid body 220. The first covering ring 42A covers the first locking ring 41A. The first locking ring 41A supports the first external terminal 30A via the first covering ring 42A. The first covering ring 42A is made of a resin material that is electrically insulating or has relatively weak conductivity.

[0031] The second terminal support portion 40B includes a second locking ring 41B and a second covering ring 42B. The second locking ring 41B extends in an annular shape to surround the second connecting hole 224B and is directly locked to the lid body 220. The second covering ring 42B covers the second locking ring 41B. The second locking ring 41B supports the second external terminal 30B via the second covering ring 42B. The second covering ring 42B is made of an electrically insulating resin material.

[0032] The insulating member 70 has electrical insulating properties. The insulating member 70 is placed between the electrode body 10 and the case 20. The insulating member 70 electrically insulates the electrode body 10 and the case 20 from each other. The insulating member 70 includes an insulating bracket 71, a circumferential insulating portion 72, a bottom insulating portion 73, and adhesive tape 74.

[0033] The insulating bracket 71 is positioned between the electrode body 10 and the lid body 220. The insulating bracket 71 is relatively rigid and is in contact with both the electrode body 10 and the lid body 220. As a result, the electrode body 10 is fixed to the case 20 in the Z direction.

[0034] The circumferential insulating portion 72 is positioned between the electrode body 10 and the circumferential wall 211. The electrode body 10 is made of a film-like material.

[0035] The bottom insulating portion 73 is positioned between the electrode body 10 and the bottom wall 210. The bottom insulating portion 73 is made of a film-like material. The bottom insulating portion 73 is fixed (adhered) to the case 20 (bottom wall 210) by adhesive tape 74.

[0036] The energy storage cell 100 according to this embodiment includes a plurality of electrode bodies 10. The energy storage cell 100 of this embodiment includes two electrode bodies 10. These electrode bodies 10 are arranged in the Y direction. The circumferential insulating portion 72 may integrally cover the plurality of electrode bodies 10 so that these electrode bodies 10 are fixed to each other.

[0037] Each of the multiple electrode bodies 10 is provided with at least one first tab 90A and at least one second tab 90B. In this embodiment, each of the multiple electrode bodies 10 is provided with multiple first tabs 90A and multiple second tabs 90B. Each first tab 90A electrically connects the first electrode 10A (described later) and the first connecting member 50A. Each second tab 90B electrically connects the second electrode 10B (described later) and the second connecting member 50B. Note that the first tab 90A is an example of an "electrode tab" in this disclosure.

[0038] Multiple first tabs 90A are arranged so as to be aligned with each other in the Y direction. Multiple first tabs 90A are joined to each other, for example by ultrasonic welding. Multiple first tabs 90A are joined to the first connecting member 50A, for example by ultrasonic welding. Multiple second tabs 90B are arranged so as to be aligned with each other in the Y direction. Multiple second tabs 90B are joined to each other, for example by ultrasonic welding. Multiple second tabs 90B are joined to the second connecting member 50B, for example by ultrasonic welding.

[0039] Figure 4 is a cross-sectional view of the electrode body 10 in the XY plane. The electrode body 10 includes a first electrode 10A, a second electrode 10B, a separator 10C, and a tape member 10D. The electrode body 10 is wound such that the first electrode 10A, the second electrode 10B, and the separator 10C surround the winding axis α. Thus, in this embodiment, the electrode body 10 is a so-called wound electrode body, but it may also be a laminated electrode body in which the first electrode 10A, the second electrode 10B, and the separator 10C are stacked in one direction (for example, the Y direction). The first electrode 10A is an example of the "electrode sheet" of this disclosure.

[0040] The first electrode 10A and the second electrode 10B have a sheet-like outer shape. The electrode body 10 is composed of a group of electrode plates in which the first electrode 10A and the second electrode 10B are wound around one or more separators 10C.

[0041] In this embodiment, the first electrode 10A is the positive electrode and the second electrode 10B is the negative electrode. However, the first electrode 10A may be the negative electrode and the second electrode 10B may be the positive electrode.

[0042] The separator 10C is provided between the first electrode 10A and the second electrode 10B. The separator 10C separates the first electrode 10A and the second electrode 10B while allowing ions to move between them. The ions are, for example, lithium ions. The separator 10C has electrical insulating properties.

[0043] Of the first electrode 10A, the second electrode 10B, and the separator 10C, the separator 10C is located on the innermost side with respect to the winding axis α. Also, of the first electrode 10A, the second electrode 10B, and the separator 10C, the separator 10C is located on the outermost side with respect to the winding axis α. The outer edge of the separator 10C in the winding direction is fixed by a tape member 10D placed on the outer surface of the separator 10C.

[0044] The first electrode 10A includes a first current collector 11A and a first active material layer 12A. The second electrode 10B includes a second current collector 11B and a second active material layer 12B.

[0045] Figure 5 is a cross-sectional view of the first electrode 10A and the first tab 90A. The first current collector 11A includes a support portion 110, a first conductive layer 111, and a second conductive layer 112. The first electrode 10A further includes a protective portion 13.

[0046] The support portion 110 is made of an electrically insulating resin composition. For example, the support portion 110 is made of a resin composition containing a polyester resin. The polyester resin is preferably polyethylene terephthalate, for example. This makes it possible to increase the rigidity of the first current collector 11A while maintaining the electrical insulation properties of the support portion 110. Consequently, the support portion 110 can be made relatively thin. The orthogonal direction DO, which is perpendicular to the thickness direction DT of the support portion 110, is approximately parallel to the Z direction.

[0047] The first conductive layer 111 is in contact with the support portion 110 on one side in the thickness direction DT. The first conductive layer 111 is located on the winding axis α side when viewed from the support portion 110. Furthermore, the first conductive layer 111 is provided over the entire surface of the coated portion 15a and the uncoated portion 15b, which will be described later, on one side in the thickness direction DT.

[0048] The second conductive layer 112 is in contact with the support portion 110 on the other side in the thickness direction DT. The second conductive layer 112 is located on the opposite side of the winding axis α when viewed from the support portion 110. Furthermore, the second conductive layer 112 is provided over the entire surface of the coated portion 15a and the uncoated portion 15b, which will be described later, on the other side in the thickness direction DT.

[0049] Each of the first conductive layer 111 and the second conductive layer 112 is made of a metal layer. Each of the first conductive layer 111 and the second conductive layer 112 is made of a metal containing aluminum. As a result, the first current collector 11A can be suitably used as a positive electrode current collector. The first current collector 11A may also be a negative electrode current collector, and the first conductive layer 111 and the second conductive layer 112 may be made of a metal containing copper.

[0050] Each of the multiple first tabs 90A is joined to the first conductive layer 111 and the second conductive layer 112, for example, by ultrasonic welding. Each of the multiple first tabs 90A extends from the support portion 110 toward Z1.

[0051] The first current collector 11A has surfaces 14a and 14b arranged in the thickness direction DT. Surface 14a is the surface of the first conductive layer 111 opposite to the support portion 110. Surface 14b is the surface of the second conductive layer 112 opposite to the support portion 110.

[0052] The first current collector 11A has a coated portion 15a to which the first active material layer 12A is applied, and an uncoated portion 15b to which the first active material layer 12A is not applied. The first current collector 11A is exposed in at least a portion of the uncoated portion 15b. The uncoated portion 15b is located on the Z1 side (the side of the first connecting member 50A (Figure 3)) than the coated portion 15a. The first active material layer 12A covers the surface 14a and the surface 14b of the coated portion 15a of the first current collector 11A, respectively.

[0053] Each of the multiple first tabs 90A includes a first foil portion 91 and a second foil portion 92. The first foil portion 91 is located on the opposite side of the support portion 110 when viewed from the first conductive layer 111. The first foil portion 91 is bonded to the first conductive layer 111. The first foil portion 91 is bonded to the first connecting member 50A (Figure 3). The second foil portion 92 is located on the opposite side of the support portion 110 when viewed from the second conductive layer 112. The second foil portion 92 is bonded to the second conductive layer 112.

[0054] The first foil portion 91 is provided on the portion 14c of the surface 14a that corresponds to the uncoated portion 15b. The first foil portion 91 is joined to the portion 14c.

[0055] The second foil portion 92 is provided on the portion 14d of the surface 14b that corresponds to the uncoated portion 15b. The second foil portion 92 is joined to portion 14d. Portion 14d is provided in the region that overlaps with portion 14c in the Z direction.

[0056] The first foil portion 91 includes a lower portion 91a and an upper portion 91b. The lower portion 91a is positioned on the first electrode 10A. Specifically, the lower portion 91a is joined to portion 14c. The upper portion 91b protrudes from the lower portion 91a (part 14c) toward the Z1 side (the side toward the first connecting member 50A (Figure 3)).

[0057] The second foil portion 92 includes a lower portion 92a and an upper portion 92b. The lower portion 92a is positioned on the first electrode 10A. Specifically, the lower portion 92a is joined to portion 14d. The upper portion 92b protrudes from the lower portion 92a (part 14d) toward the Z1 side (the side toward the first connecting member 50A (Figure 3)).

[0058] The upper portion 91b is joined to the upper portion 92b. Specifically, the upper portion 91b and the upper portion 92b are joined at the joint portion 93 on the Z1 side of the first current collector 11A, for example by ultrasonic welding.

[0059] The first foil portion 91 (upper portion 91b) extends further toward Z1 than the upper end portion 92c (Z1 side end) of the second foil portion 92 (upper portion 92b). The joint portion 93 is the portion where the upper portion 92b and the Z2 side base portion of the upper portion 91b are joined. The joint portion 93 extends toward Z1 from, for example, the upper end portion 10E of the electrode body 10. The upper end portion 10E of the electrode body 10 is the upper end portion of the separator 10C (Figure 4). The lower end portion of the joint portion 93 may be located, for example, toward Z1 or Z2 than the upper end portion 10E.

[0060] As described above, the length of the first foil portion 91 in the orthogonal direction DO (Z direction) perpendicular to the thickness direction DT is longer than the length of the second foil portion 92 in the orthogonal direction DO. However, the configuration of the first tab 90A is not limited to this. The length of the second foil portion 92 in the orthogonal direction DO may be longer than the length of the first foil portion 91 in the orthogonal direction DO. Furthermore, the second foil portion 92 may be joined to the first connecting member 50A, while the first foil portion 91 may not be joined to the first connecting member 50A.

[0061] The first active material layer 12A includes an inner active material layer 121A and an outer active material layer 122A. The inner active material layer 121A is laminated on the first conductive layer 111. The outer active material layer 122A is laminated on the second conductive layer 112.

[0062] The upper edge of the first active material layer 12A is separated from each of the multiple first tabs 90A. Specifically, the upper edge of the inner active material layer 121A is separated from each of the first foil portions 91 of the multiple first tabs 90A. The upper edge of the outer active material layer 122A is separated from each of the second foil portions 92 of the multiple first tabs 90A.

[0063] The separator 10C is laminated on the first active material layer 12A in the radial direction centered on the winding axis α (Figure 4). The separator 10C is laminated on the inner active material layer 121A in the same radial direction. The separator 10C is also laminated on the outer active material layer 122A in the same radial direction.

[0064] The protective part 13 has electrical insulating properties and is made of, for example, ceramic. The protective part 13 covers the upper part of the first active material layer 12A. The protective part 13 further covers the first current collector 11A between the first tab 90A and the first active material layer 12A.

[0065] The protective portion 13 includes an inner protective portion 131 and an outer protective portion 132. The inner protective portion 131 covers the upper part of the inner active material layer 121A. The inner protective portion 131 covers the first conductive layer 111 between the first foil portion 91 and the inner active material layer 121A. The outer protective portion 132 covers the upper part of the outer active material layer 122A. The outer protective portion 132 covers the second conductive layer 112 between the second foil portion 92 and the outer active material layer 122A.

[0066] Figure 6 is a cross-sectional view of the energy storage cell 100 along the Y direction. Multiple first tabs 90A (upper portions 91b) are arranged in the Y direction. In Figure 6, for simplification, the first tabs 90A provided on each electrode body 10 are omitted from the illustration. Also, in Figure 6, for simplification, the illustration of the upper portion 92b is omitted. Furthermore, in Figure 6 and other figures, an example is schematically shown in which multiple upper portions 91b are arranged overlapping on the first connecting member 50A, but for example, each upper portion 91b may be in direct contact with the first connecting member 50A by being arranged offset from each other. In the following, the portion formed by stacking the portions of each of the multiple upper portions 91b that are arranged on the first connecting member 50A will be referred to as the tab stacking portion 90.

[0067] The first connecting member 50A includes a pair of connecting portions 51 that are connected to each first tab 90A (upper portion 91b). Each of the pair of connecting portions 51 has a lower surface 51a and an upper surface 51b. The lower surface 51a is positioned facing the electrode body 10 side (Z2 side). The upper surface 51b is positioned on the opposite side from the lower surface 51a (facing the Z1 side). The lower surface 51a and the upper surface 51b are examples of the "first surface" and "second surface" of this disclosure, respectively.

[0068] In conventional energy storage cells, the tabs are welded to the underside of the current collector plate. As a result, the tabs are bent in the narrow space between the current collector plate and the electrode body. This can lead to excessive bending stress on the tabs and, in some cases, cause them to break.

[0069] Therefore, in this embodiment, the first tab 90A (tab stacking portion 90) is connected to the upper surface 51b of the connecting portion 51. The upper surface 51b and the first tab 90A (tab stacking portion 90) are joined together, for example, by ultrasonic welding. In other words, the tab stacking portion 90 is fixed to the upper surface 51b.

[0070] The tab stacked portion 90 is not connected to the lower surface 51a of the connecting portion 51. In other words, the tab stacked portion 90 does not have any portion that is connected (in contact) with the lower surface 51a. A space S1 is formed between each of the multiple upper portions 91b and the lower surface 51a.

[0071] The tab stacking portion 90 includes a connecting portion 94 that is connected to the upper surface 51b. The connecting portion 94 is positioned between the first connecting member 50A (connecting portion 51) and the insulating bracket 71. The connecting portion 94 may also be joined to the insulating bracket 71 by ultrasonic welding or the like.

[0072] Figure 7 is a magnified view of the vicinity of the connection portion 51 in Figure 6. Although Figure 7 only shows the configuration near the connection portion 51 on the Y1 side, the configuration near the connection portion 51 on the Y2 side is the same as that shown in Figure 6, so a detailed explanation is omitted.

[0073] The first connecting member 50A (connecting portion 51) includes a first connecting surface 51c and a second connecting surface 51d. Each of the first connecting surface 51c and the second connecting surface 51d connects the lower surface 51a and the upper surface 51b. The first connecting surface 51c is an example of a "connecting surface" as described herein.

[0074] The first connection surface 51c is the surface located on the opposite side from the second connection surface 51d. Specifically, in each of the pair of connection parts 51, the second connection surface 51d is positioned facing the other connection part 51. That is, in each of the pair of connection parts 51, the first connection surface 51c is positioned facing the opposite side from the other connection part 51. This makes it possible to suppress interference between the tab stacking parts 90 connected to each of the pair of connection parts 51 in a configuration where the tab stacking part 90 and the first connection surface 51c come into contact, as will be described later.

[0075] The tab-laminated portion 90 is in contact with the first connection surface 51c. In other words, the tab-laminated portion 90 includes a contact portion 95 that is in contact with the first connection surface 51c. The contact portion 95 may be joined to the first connection surface 51c by ultrasonic welding or the like.

[0076] The contact between the tab stacking portion 90 and the first connecting surface 51c prevents the formation of a gap between the tab stacking portion 90 and the first connecting surface 51c. As a result, it is possible to prevent the length of the tab stacking portion 90 (upper portion 91b) from increasing. Note that the tab stacking portion 90 and the first connecting surface 51c may be spaced apart.

[0077] Specifically, the first connecting surface 51c is composed of a side surface 51e, a first inclined surface 51f, and a second inclined surface 51g. The contact portion 95 is in contact with the side surface 51e. The first inclined surface 51f is an example of an "inclined surface" as described herein.

[0078] The first inclined surface 51f connects the upper surface 51b and the side surface 51e. The side surface 51e extends from the first inclined surface 51f toward the lower surface 51a side (Z2 side).

[0079] The second inclined surface 51g connects the lower surface 51a and the side surface 51e. That is, the side surface 51e connects the first inclined surface 51f and the second inclined surface 51g. Note that the second inclined surface 51g does not necessarily have to be formed on the connecting portion 51.

[0080] Each of the first inclined surface 51f and the second inclined surface 51g is formed in a flat shape. Note that each of the first inclined surface 51f and the second inclined surface 51g may be a surface formed by chamfering the corners of the connecting portion 51. Furthermore, at least one of the first inclined surface 51f and the second inclined surface 51g may have, for example, a curved shape.

[0081] The first inclined surface 51f is inclined such that it approaches the bottom surface 51a as it moves from the top surface 51b towards the side surface 51e. The second inclined surface 51g is inclined such that it approaches the top surface 51b as it moves from the bottom surface 51a towards the side surface 51e.

[0082] In this embodiment, the tab stacking portion 90 extends along the side surface 51e and the first inclined surface 51f to the upper surface 51b. This makes it possible to suppress damage (breakage) to the tab stacking portion 90 compared to when a corner (sharp corner) is formed at the position of the first inclined surface 51f.

[0083] The tab-laminated portion 90 further includes a contact portion 96. The contact portion 96 is in contact with the first inclined surface 51f. The contact portion 96 and the first inclined surface 51f may be joined by ultrasonic welding or the like.

[0084] The tab-laminated portion 90 is not in contact with the second inclined surface 51g and the lower surface 51a. However, the tab-laminated portion 90 and the second inclined surface 51g may be in contact. In this case, compared to the case where a corner (sharp corner) is formed at the position of the second inclined surface 51g, damage (breakage) to the tab-laminated portion 90 can be suppressed.

[0085] As described above, in this embodiment, the first tab 90A (tab stacking portion 90) is connected to the upper surface 51b of the first connecting member 50A (connecting portion 51). This reduces the stress (bending stress) on the first tab 90A compared to the case where the first tab 90A is housed in the narrow space between the first connecting member 50A and the electrode body 10. As a result, damage to the first tab 90A can be suppressed.

[0086] <Variation> Figure 8 shows the configuration of a tab stacking section 190, which is a first modified example of the tab stacking section 90 shown in Figure 7. The tab stacking section 190 differs from the tab stacking section 90 in that it also contacts the lower surface 51a of the connecting section 51. In other words, in addition to the connecting section 94, contact section 95, and contact section 96, the tab stacking section 190 has a connecting section 97 that is connected (fixed) to the lower surface 51a. The connecting section 97 and the lower surface 51a may be joined by ultrasonic welding or the like.

[0087] This allows the tab stacking section 190 to be fixed to the connecting section 51 more stably than when the connecting section 97 is not provided.

[0088] The tab-laminated portion 190 further has a contact portion 98 that is in contact with the second inclined surface 51g. The contact portion 98 and the second inclined surface 51g may be joined by ultrasonic welding or the like.

[0089] Figure 9 shows a second modified example of the tab stacking section 90 shown in Figure 7. As shown in Figure 9, the tab stacking section 90 is composed of a portion of the multiple upper portions 91b (hereinafter referred to as the upper portion 91c). The tab stacking section 290 is composed of the remaining portion of the multiple upper portions 91b (hereinafter referred to as the upper portion 91d). In each of the two electrode bodies 10 (Figure 6), the upper portion 91d may be positioned on the other electrode body 10 side (Y2 side in Figure 9) than the upper portion 91c. The upper portion 91c and the upper portion 91d are examples of the "first electrode piece" and "second electrode piece" of this disclosure, respectively.

[0090] The upper portion 91c has an end 91e on the side of the first connecting member 50A (connecting portion 51). That is, end 91e is the end of the upper portion 91c opposite to the end on the side of the first electrode 10A (Figure 5). The upper portion 91d has an end 91f on the side of the first connecting member 50A (connecting portion 51). That is, end 91f is the end of the upper portion 91d opposite to the end on the side of the first electrode 10A. Ends 91e and 91f are examples of the "first end" and "second end" of this disclosure, respectively.

[0091] The end portion 91e of the upper portion 91c is connected to the upper surface 51b of the connecting portion 51. The end portion 91f of the upper portion 91d is connected to the lower surface 51a of the connecting portion 51.

[0092] This allows the thickness of the ends of the upper portion 91b that are laminated on the upper surface 51b to be reduced compared to the case where all ends of the upper portion 91b are connected to the upper surface 51b. As a result, even if the space between the connection portion 51 and the insulating bracket 71 (Figure 6) is narrow, the first tab 90A can be easily connected to the connection portion 51. Furthermore, the space can be made even smaller, and the energy storage cell 100 can be made smaller (lower in height).

[0093] The tab-laminated section 290 is connected only to the bottom surface 51a. The tab-laminated section 290 may be joined to the bottom surface 51a by ultrasonic welding or the like. That is, the tab-laminated section 290 is not in contact with the top surface 51b, the side surface 51e, the second connecting surface 51d, the first inclined surface 51f, and the second inclined surface 51g. The tab-laminated section 290 may be connected to at least one of the side surface 51e, the first inclined surface 51f, and the second inclined surface 51g by ultrasonic welding or the like.

[0094] In the above embodiment, an example was shown in which the first tab 90A of the first electrode 10A is connected to the upper surface 51b, etc., but the disclosure is not limited thereto. The second tab 90B of the second electrode 10B may be connected to the upper surface of the second connecting member 50B, etc.

[0095] The configurations of each of the above embodiments and each of the modified examples may be combined with each other.

[0096] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of this disclosure is defined by the claims rather than the description of the embodiments above, and includes all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0097] 10 Electrode body, 10A First electrode (electrode sheet), 50A First connecting member (current collector plate), 51a Bottom surface (first surface), 51b Top surface (second surface), 51c Connection surface, 51e Side surface, 51f First inclined surface (inclined surface), 90A First tab (electrode tab), 91c Upper part (first electrode piece), 91d Upper part (second electrode piece), 91e End (first end), 91f End (second end), 100 Energy storage cell.

Claims

1. An electrode body including an electrode sheet, A current collector plate is positioned opposite the electrode body, The electrode sheet and the current collector plate are connected by an electrode tab, The aforementioned current collector plate is The first surface is positioned facing the electrode body side, A second surface is located on the opposite side from the first surface, The electrode tab is connected to the second surface, forming an energy storage cell.

2. The current collector plate includes a connecting surface that connects the first surface and the second surface, The energy storage cell according to claim 1, wherein the electrode tab is in contact with the connection surface.

3. The aforementioned connection surface is An inclined surface connected to the second surface, It has a side surface that is connected to the inclined surface and extends from the inclined surface toward the first surface, The inclined surface is inclined so as it moves from the second surface toward the side surface, it approaches the first surface. The energy storage cell according to claim 2, wherein the electrode tab extends along the side surface and the inclined surface to the second surface.

4. The energy storage cell according to any one of claims 1 to 3, wherein the electrode tab is also connected to the first surface.

5. The electrode tab includes a first electrode piece and a second electrode piece, Each of the first electrode piece and the second electrode piece connects the electrode sheet and the current collector plate. The first electrode piece has a first end on the current collector plate side, The second electrode piece has a second end on the current collector plate side, The first end of the first electrode piece is connected to the second surface, The energy storage cell according to any one of claims 1 to 3, wherein the second end of the second electrode piece is connected to the portion of the current collector plate that is on the electrode body side of the second surface.

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