Method for manufacturing an energy storage cell and an energy storage cell

Abstract

The present invention provides a method for manufacturing energy storage cells that enables the efficient production of electrode sheets in which electrode foils are provided on both surfaces of an insulating support layer. [Solution] The method for manufacturing the energy storage cell 100 comprises the steps of: forming a sheet member 120 including a conductive layer 111 and a first active material layer 12A; bending the sheet member 120; and arranging the inner surface 111D of the bent conductive layer 111 on the insulating support layer 110. The bending step is a step of forming an inner portion 111A, an outer portion 111B, a connecting portion 111C, and a conductive layer 111 by bending the sheet member 120. The bending step includes bringing the inner surface 110A of the insulating support layer 110 into contact with the inner portion 111A, bringing the outer surface 110B of the insulating support layer 110 into contact with the outer portion 111B, and bringing the end portion 110C of the insulating support layer 110 to face the connecting portion 111C.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a storage battery cell and a storage battery cell.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2020-198290 (Patent Document 1) discloses a cell including a composite current collector including an organic support layer and a conductive layer provided on the organic support layer. Patent Document 1 discloses an example in which conductive layers are provided on each of a first surface and a second surface arranged in the thickness direction of the organic support layer. Each of the conductive layers provided on the first surface and the second surface is exemplified as being formed by a physical vapor deposition method (such as a vapor deposition method or a sputtering method).

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 as described above, conductive layers (electrode foils) are formed on each of the first surface and the second surface of the organic support layer (insulating support layer) by a physical vapor deposition method. When forming the conductive layer by a physical vapor deposition method, since it takes a relatively long time for the growth of the conductive layer, it is considered that the time required for manufacturing the electrode sheet becomes long. Thus, it is desired to efficiently manufacture an electrode sheet in which electrode foils are formed on both surfaces of the insulating support layer.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a method for manufacturing a storage battery cell and a storage battery cell capable of efficiently manufacturing an electrode sheet in which electrode foils are provided on both surfaces of an insulating support layer.

Means for Solving the Problems

[0006] A method for manufacturing an energy storage cell according to the first aspect of this disclosure is a manufacturing process for an energy storage cell comprising an electrode sheet, comprising: a forming step of forming a sheet member comprising an electrode foil including a first main surface and a second main surface and an active material layer formed on the first main surface; a bending step of bending the sheet member; and a placement step of arranging the bent second main surface on an insulating support layer. The bending step is a step of forming a first portion, a second portion arranged with the first portion in the thickness direction of the insulating support layer, and a connecting portion connecting the first portion and the second portion on the electrode foil by bending the sheet member. If the direction intersecting the thickness direction is defined as the intersecting direction, then either the bending step or the placement step includes forming an electrode sheet by bringing the first surface provided at one end of the insulating support layer in the thickness direction into contact with the first portion, bringing the second surface on the opposite side of the insulating support layer from the first surface into contact with the second portion, and bringing the end of the insulating support layer in the intersecting direction and the connecting portion facing each other in the intersecting direction.

[0007] A power storage cell according to a second aspect of the present disclosure comprises a current collector plate and an electrode body including an electrode sheet connected to the current collector plate. The electrode sheet includes an insulating support layer, an electrode foil, and an active material layer formed on the electrode foil. The active material layer is located on the side of the electrode foil opposite to the insulating support layer. The electrode foil has a first portion and a second portion arranged in the thickness direction of the insulating support layer, and a connecting portion connecting the first portion and the second portion. The first portion is located on a first surface provided at one end of the insulating support layer in the thickness direction. The second portion is located on a second surface of the insulating support layer opposite to the first surface. If the direction intersecting the thickness direction is defined as the intersecting direction, the connecting portion faces the end of the insulating support layer on the first direction side of the intersecting direction, with a gap in between. [Effects of the Invention]

[0008] According to this disclosure, an electrode sheet having electrode foils provided on both surfaces of an insulating support layer can be efficiently manufactured. [Brief explanation of the drawing]

[0009] [Figure 1] This diagram shows the configuration of a vehicle equipped with an energy storage device. [Figure 2] This is a perspective view showing the configuration of the energy storage device and frame members. [Figure 3] This is a cross-sectional view along line III-III in Figure 2. [Figure 4] This is a perspective view showing the configuration of an energy storage cell. [Figure 5] This is an exploded perspective view showing the configuration of an energy storage cell. [Figure 6] This is a cross-sectional view taken in the direction of the arrow VI-VI in Figure 4. [Figure 7] This is a cross-sectional view taken in the direction of the line VII-VII in Figure 6. [Figure 8] This is a partially enlarged cross-sectional view showing the configuration of the first electrode. [Figure 9] This is a partially enlarged cross-sectional view showing the configuration of the second electrode. [Figure 10] This is a flowchart illustrating the manufacturing method of an energy storage cell. [Figure 11] This is a flowchart showing the details of the process for forming the first electrode. [Figure 12] This figure shows the details of S11 in Figure 11. [Figure 13] This is a cross-sectional view taken in the direction of the arrow XIII-XIII in Figure 12. [Figure 14] This figure shows the details of S12 in Figure 11. [Figure 15] This figure shows the details of S13 in Figure 11. [Figure 16] This figure shows the details of S14 in Figure 11. [Figure 17] This figure shows the details of S15 in Figure 11. [Figure 18] This figure shows the details of S16 in Figure 11. [Figure 19] This is a plan view showing a pore formed in the first active material layer according to a modified example of one embodiment. [Figure 20] This is a cross-sectional view taken in the direction of the arrow along the line XX-XX in Figure 19. [Figure 21]It is a cross-sectional view showing an uncoated portion of a first active material layer according to a modification of an embodiment. [Figure 22] It is a cross-sectional view showing an insulating layer formed on an uncoated portion of a first active material layer according to a modification of an embodiment. [Figure 23] It is a cross-sectional view showing the configuration of a first electrode according to a modification of an embodiment.

Mode for Carrying Out the Invention

[0010] Embodiments of the present disclosure will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are given the same numbers.

[0011] FIG. 1 is a diagram schematically showing a vehicle including a power storage device in the present embodiment. As shown in FIG. 1, the vehicle 1 includes a vehicle body 2 and a power storage device 3. Examples of the vehicle 1 include a hybrid electric vehicle, a plug-in hybrid electric vehicle, and a battery electric vehicle. Note that the power storage device 3 may be provided in an electrical device other than an electric vehicle (for example, a stationary power storage device). In the present specification, the X direction, the Y direction, and the Z direction are directions orthogonal to each other. For example, the X direction and the Y direction may be the front-rear direction and the left-right direction, respectively, when the power storage device 3 is mounted on an electric vehicle. The Z direction may be the up-down direction. Specifically, the Z1 direction and the Z2 direction may be the upper direction and the lower direction, respectively.

[0012] The vehicle body 2 includes a frame member 4. The frame member 4 is disposed at the bottom of the vehicle body 2. The frame member 4 is formed in a substantially rectangular prism shape surrounding the power storage device 3. The power storage device 3 is attached to the frame member 4.

[0013] Figure 2 is a schematic perspective view showing the energy storage device 3 and the frame member 4. As shown in Figure 2, the energy storage device 3 comprises multiple energy storage stacks 5.

[0014] Each energy storage stack 5 is formed in the shape of a rectangular parallelepiped, elongated in the Y direction. Multiple energy storage stacks 5 are arranged in a line along the X direction.

[0015] Figure 3 is a cross-sectional view (cross-sectional view of the energy storage stack 5) taken in the direction of the arrow III-III in Figure 2. Each energy storage stack 5 contains a plurality of energy storage cells 100 arranged in the Y direction. A pressure relief valve SV is formed at the bottom of each energy storage cell 100.

[0016] Figure 4 is a perspective view showing the energy storage cell 100 according to this embodiment. As shown in Figure 4, 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.

[0017] The energy storage cell 100 comprises 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. Figure 4 shows a schematic representation of the electrode body 10.

[0018] Case 20 is conductive. The conductive portion of Case 20 is made of a metal such as aluminum. Case 20 houses the electrode body 10. Case 20 also houses an electrolyte solution, which is not shown in the diagram.

[0019] 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 rising from the bottom wall 210. The pressure relief valve SV (Figure 3) is formed in the bottom wall 210.

[0020] 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 other means so as to close the opening in the peripheral wall 211.

[0021] The first external terminal 30A and the second external terminal 30B are provided in the energy storage cell 100 so as to be exposed to the outside. In this embodiment, the first external terminal 30A is the positive terminal and the second external terminal 30B is the negative terminal. The first external terminal 30A and the second external terminal 30B are aligned in the X direction.

[0022] The first terminal support portion 40A is locked to the lid body 220. The first terminal support portion 40A supports the first external terminal 30A from the outer circumference side of the first external terminal 30A. The second terminal support portion 40B is locked to the lid body 220. The second terminal support portion 40B supports the second external terminal 30B from the outer circumference side of the second external terminal 30B.

[0023] Figure 5 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.

[0024] The bottom wall 210 includes the bottom body 212, an outer protective film 213, and an inner protective film 214. The peripheral wall 211 rises from the bottom body 212. The pressure relief valve SV is provided on 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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 within 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] As shown in Figure 5, 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 aligned 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.

[0039] 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.

[0040] Figure 6 is a cross-sectional view taken in the direction of the arrow VI-VI in Figure 4. As shown in Figure 6, the multiple first tabs 90A are arranged so as to be aligned with each other in the Y direction. The multiple first tabs 90A are joined to each other, for example by ultrasonic welding. The multiple first tabs 90A are joined to the first connecting member 50A, for example by ultrasonic welding. The multiple second tabs 90B are arranged so as to be aligned with each other in the Y direction. The multiple second tabs 90B are joined to each other, for example by ultrasonic welding. The multiple second tabs 90B are joined to the second connecting member 50B, for example by ultrasonic welding.

[0041] Figure 7 is a cross-sectional view of the electrode body of Figure 6, viewed in the direction of the VII-VII arrow. 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Figure 8 is a cross-sectional view of the first electrode 10A. The first current collector 11A includes an insulating support layer 110 and a conductive layer 111. The conductive layer 111 is an example of the "electrode foil" of this disclosure.

[0048] The insulating support layer 110 is made of an electrically insulating resin composition. For example, the insulating support layer 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 insulating support layer 110. Consequently, the insulating support layer 110 can be made relatively thin. The orthogonal direction DO, which is perpendicular to the thickness direction DT of the insulating support layer 110, is substantially parallel to the Z direction. Note that the thickness direction DT and the orthogonal direction DO are examples of the "thickness direction" and "intersecting direction" in this disclosure, respectively.

[0049] The conductive layer 111 consists of a metal layer. In this embodiment, the conductive layer 111 is made of a metal containing aluminum. This allows the first current collector 11A to be suitably used as a positive electrode current collector. The first current collector 11A may also be a negative electrode current collector, and the conductive layer 111 may be made of a metal containing copper.

[0050] Therefore, it is desirable to efficiently manufacture electrodes in which conductive layers are formed on both surfaces of the insulating support layer.

[0051] Therefore, in this embodiment, the conductive layer 111 has an inner portion 111A and an outer portion 111B arranged in the thickness direction DT, and a connecting portion 111C that connects the inner portion 111A and the outer portion 111B. The inner portion 111A, the outer portion 111B, and the connecting portion 111C are formed by bending the conductive layer 111 into a U-shape. The conductive layer 111 is a single member that includes at least one bent portion. That is, the connecting portion 111C is integrally formed with each of the inner portion 111A and the outer portion 111B. The inner portion 111A is positioned closer to the winding axis α (Figure 7) than the outer portion 111B when the first electrode 10A is wound around it. Note that the inner portion 111A and the outer portion 111B are examples of the "first portion" and "second portion" of this disclosure, respectively.

[0052] The connecting portion 111C has a curved shape due to being bent. The connecting portion 111C is bent so as to be convex downward (in the DO2 direction). Note that the connecting portion 111C is an example of the "bent portion" in this disclosure.

[0053] The inner portion 111A is located on the inner surface 110A of the insulating support layer 110, which is provided at one end in the thickness direction DT. The outer portion 111B is located on the outer surface 110B of the insulating support layer 110, which is opposite to the inner surface 110A. The outer surface 110B is provided at the other end of the insulating support layer 110 in the thickness direction DT. The connecting portion 111C is located opposite the end 110C of the insulating support layer 110 in the first direction (DO2 direction) of the orthogonal direction DO, in the orthogonal direction DO. Note that the DO2 direction is the same direction as the Z2 direction (the direction towards the back of the page in Figure 7). Note that the inner surface 110A and the outer surface 110B are examples of the "first surface" and "second surface" of this disclosure, respectively.

[0054] This allows conductive layers to be placed on both the inner surface 110A and the outer surface 110B simply by bending the conductive layer 111. As a result, the first electrode 10A can be manufactured easily and efficiently.

[0055] The conductive layer 111 includes an inner surface 111D and an outer surface 111E. The inner surface 111D is in contact with (facing) the insulating support layer 110. The outer surface 111E is the back surface of the inner surface 111D. That is, the outer surface 111E is provided on the side opposite to the insulating support layer 110. The first active material layer 12A is coated on the outer surface 111E. The first active material layer 12A is provided on the inner portion 111A, the outer portion 111B, and the connecting portion 111C, respectively. The inner surface 111D is an example of the "second main surface" in this disclosure. The outer surface 111E is an example of the "electrode surface" and "first main surface" in this disclosure.

[0056] The first active material layer 12A includes an inner active material portion 121, an outer active material portion 122, and a connecting active material portion 123. The inner active material portion 121 is coated on the inner portion 111A of the conductive layer 111. The outer active material portion 122 is coated on the outer portion 111B of the conductive layer 111. The connecting active material portion 123 is coated on the connecting portion 111C of the conductive layer 111. The connecting active material portion 123 connects the inner active material portion 121 and the outer active material portion 122. The inner active material portion 121 and the outer active material portion 122 are examples of the "first active material portion" and the "second active material portion" of this disclosure, respectively. The connecting active material portion 123 is an example of the "bending portion coated portion" of this disclosure.

[0057] The inner portion 111A is composed of an inner coated portion 111F and an inner tab portion 91. The inner coated portion 111F is the portion of the inner portion 111A to which the first active material layer 12A (inner active material portion 121) is coated. The inner tab portion 91 is the portion of the inner portion 111A to which the first active material layer 12A (inner active material portion 121) is not coated. The inner tab portion 91 is integrally formed with the inner coated portion 111F. The inner tab portion 91 and the first active material layer 12A are examples of the "first protruding portion" and "active material layer" of this disclosure, respectively.

[0058] The inner tab portion 91 protrudes in the DO1 direction from the inner active material portion 121 in the orthogonal DO direction. Specifically, the inner tab portion 91 extends in the DO1 direction from the DO1 direction end of the inner coating portion 111F. The DO1 direction is the direction opposite to the DO2 direction. The inner tab portion 91 protrudes upward (in the DO1 direction) from the upper end portion 10E of the electrode body 10. The upper end portion 10E is the upper end portion of the separator 10C (Figure 7). The DO1 direction is an example of the "second direction" in this disclosure.

[0059] The outer portion 111B is composed of an outer coated portion 111G and an outer tab portion 92. The outer coated portion 111G is the portion of the outer portion 111B to which the first active material layer 12A (outer active material portion 122) is coated. The outer tab portion 92 is the portion of the outer portion 111B to which the first active material layer 12A (outer active material portion 122) is not coated. The outer tab portion 92 is integrally formed with the outer coated portion 111G. The outer tab portion 92 is an example of the "second protruding portion" of this disclosure.

[0060] The outer tab portion 92 protrudes in the DO1 direction from the outer active material portion 122 in the orthogonal DO direction. Specifically, the outer tab portion 92 extends in the DO1 direction from the DO1 direction end of the outer coating portion 111G. The outer tab portion 92 protrudes upward (in the DO1 direction) from the upper end portion 10E of the electrode body 10.

[0061] Each of the inner tab portion 91 and the outer tab portion 92 is connected to the first connecting member 50A. This reduces the number of parts in the first electrode 10A and simplifies its configuration compared to the case where the conductive layer 111 and the first connecting member 50A are electrically connected by a separate component from the conductive layer 111. The first tab 90A is composed of the inner tab portion 91 and the outer tab portion 92.

[0062] In detail, the inner tab portion 91 has an adjacent portion 91a and a connecting portion 91b. The adjacent portion 91a is adjacent to the first connecting member 50A and extends along the first connecting member 50A. The adjacent portion 91a may extend, for example, along the thickness direction DT. The adjacent portion 91a is joined to the first connecting member 50A. The connecting portion 91b connects the adjacent portion 91a to the inner coated portion 111F. The connecting portion 91b may extend, for example, along the orthogonal direction DO. Note that when we say that the adjacent portion 91a is joined to the first connecting member 50A, we also mean that the adjacent portion 91a is indirectly joined to the first connecting member 50A via the adjacent portion 92a (described later).

[0063] The outer tab portion 92 has an adjacent portion 92a and a connecting portion 92b. The adjacent portion 92a is adjacent to the first connecting member 50A and extends along the first connecting member 50A. The adjacent portion 92a may extend, for example, along the thickness direction DT. The adjacent portion 92a is joined to the first connecting member 50A. The connecting portion 92b connects the adjacent portion 92a to the outer coated portion 111G. The connecting portion 92b may extend, for example, along the orthogonal direction DO. Note that when the adjacent portion 92a is said to be joined to the first connecting member 50A, it also includes when the adjacent portion 92a is indirectly joined to the first connecting member 50A via the adjacent portion 91a.

[0064] Although Figure 8 schematically shows an example where adjacent portions 91a and 92a are overlapping, for example, adjacent portions 91a and 92a may be offset from each other, so that each of them is in direct contact with the first connecting member 50A.

[0065] Furthermore, although Figure 8 shows an example in which both the inner tab portion 91 and the outer tab portion 92 extend to the first connecting member 50A, only one of the inner tab portion 91 or the outer tab portion 92 may extend to the first connecting member 50A. For example, the upper end portion of the outer tab portion 92 may be joined to the connecting portion 91b of the inner tab 91.

[0066] Furthermore, the lower end of the first electrode 10A (the lower end of the connecting active material portion 123) is located above the lower end 10F of the electrode body 10. The lower end 10F is the lower end of the separator 10C (Figure 7).

[0067] A gap Ga is formed between the end portion 110C of the insulating support layer 110 and the connection portion 111C of the conductive layer 111. The size of the gap Ga may be set, for example, based on the pressure applied to the insulating support layer 110 during the manufacturing process of the energy storage cell 100. Specifically, the size of the gap Ga may be set based on the amount by which the insulating support layer 110 extends in the orthogonal direction DO due to the above pressure.

[0068] As a result, even if the insulating support layer 110 stretches due to pressure, the gap Ga can be used as a space to accommodate (release) the stretched portion of the insulating support layer 110. Furthermore, when the cell temperature rises due to charging and discharging of the energy storage cell 100, causing the insulating support layer 110 to deform and stretch, the gap Ga provides space for the insulating support layer 110 to stretch, thereby suppressing problems such as bending of the insulating support layer 110.

[0069] A notch 123a is formed in the connecting active material portion 123. The connecting active material portion 123 includes an outer surface 123b provided on the side opposite to the conductive layer 111. The outer surface 123b is curved so as to be convex downward (in the DO2 direction). The notch 123a is formed in the outer surface 123b. Note that the outer surface 123b is an example of the "active material surface" in this disclosure.

[0070] As a result, when bending the conductive layer 111 with the first active material layer 12A in place, it can be bent starting from the notch 123a, thus simplifying the bending process of the conductive layer 111. Furthermore, since the first active material layer 12A is bent around the notch 123a, peeling of the bent portion of the first active material layer 12A can be suppressed compared to when the notch 123a is not formed.

[0071] The notch 123a may be formed at the lower end (the part closest to the DO2 direction) of the first active material layer 12A. Alternatively, the notch 123a may be formed at the midpoint between the position of the inner active material portion 121 and the position of the outer active material portion 122 in the thickness direction DT. Even in the portion where the notch 123a is formed, the conductive layer 111 is not exposed and is covered by the first active material layer 12A.

[0072] The separator 10C (Figure 7) is laminated on the first active material layer 12A in the radial direction centered on the winding axis α (Figure 7). The separator 10C is laminated on the inner active material portion 121 in the same radial direction. The separator 10C is also laminated on the outer active material portion 122 in the same radial direction.

[0073] Figure 9 is a cross-sectional view of the second electrode 10B. The second electrode 10B is laminated in the radial direction on the first active material layer 12A (Figures 7 and 8) via the separator 10C (Figure 7). More specifically, the second electrode 10B is laminated in the radial direction on the inner active material portion 121 (Figure 8) via the separator 10C, and also on the outer active material portion 122 (Figure 8) via the separator 10C.

[0074] The second electrode 10B includes a second current collector 11B and a second active material layer 12B. The second current collector 11B includes a conductive support portion 113 and a plurality of second tabs 90B. The conductive support portion 113 extends along the orthogonal direction DO (Z direction). The plurality of second tabs 90B extend from the upper end of the conductive support portion 113. The plurality of second tabs 90B are joined to each other by ultrasonic welding and are also joined to the second connecting member 50B (Figures 5 and 6).

[0075] The multiple second tabs 90B and conductive support portion 113 are made of an integral material, for example, metal foil. In this embodiment, the multiple second tabs 90B and conductive support portion 113 are made of a metal including copper, for example. This allows the second current collector 11B to be suitably used as a negative electrode current collector. If the first current collector 11A is a negative electrode current collector, the multiple second tabs 90B and conductive support portion 113 may be made of a metal including aluminum.

[0076] The second active material layer 12B is laminated on both sides of the conductive support portion 113 of the second current collector 11B. In this embodiment, since the second electrode 10B is the negative electrode, the DO1-side edge of the second active material layer 12B is located closer to DO1 than the DO1-side edge of the first active material layer 12A. The DO2-side edge of the second active material layer 12B is located closer to DO2 than the DO2-side edge of the first active material layer 12A.

[0077] (Manufacturing method for energy storage cells) Next, a method for manufacturing the energy storage cell 100 of this disclosure will be described with reference to Figures 10 to 18.

[0078] Figure 10 shows a schematic manufacturing flow of the method for manufacturing the energy storage cell 100. In step S10, the first electrode 10A is formed. Next, in step S20, the second electrode 10B is formed. Note that the order of steps S10 and S20 is not limited to the example above.

[0079] Next, in step S30, the electrode body 10 is formed by winding a sheet member in which a separator 10C (Figure 7) is sandwiched between the first electrode 10A formed in step S10 and the second electrode 10B formed in step S20.

[0080] In step S40, the two electrode bodies 10 formed in step S30 are placed in the case 20 (Figure 4).

[0081] In step S50, the first tab 90A (adjacent portions 91a, 92a) (Figure 8) and the first connecting member 50A are joined. For example, the first tab 90A and the first connecting member 50A may be joined by ultrasonic bonding.

[0082] In step S60, the second tab 90B and the second connecting member 50B are joined. For example, the second tab 90B and the second connecting member 50B may be joined by ultrasonic bonding. Note that the order of steps S50 and S60 is not limited to the example above.

[0083] Figure 11 shows a detailed manufacturing flow for step S10 in Figure 10. Step S10 includes steps S11 to S16.

[0084] In step S11, a sheet member 120 constituting the first electrode 10A is formed. In step S12, the first active material layer 12A coated on the conductive layer 111 is solidified by pressing. In step S13, the surface of the conductive layer 111 is subjected to corona treatment. The surface of the insulating support layer 110 may also be subjected to corona treatment. Furthermore, steps S11 and S12 are examples of the "forming process" described herein.

[0085] In step S14, the insulating support layer 110 is placed on the conductive layer 111. In step S15, the conductive layer 111 (sheet member 120) is bent. In step S16, the conductive layer 111 and the insulating support layer 110 are joined together.

[0086] As described above, the step of placing the insulating support layer 110 on the conductive layer 111 (S14) is performed after the step of pressing the first active material layer 12A (S12). This makes it possible to suppress deformation of the insulating support layer 110 by crushing (stretching) during the pressing process.

[0087] Figure 12 shows the process of step S11 in Figure 11. In Figure 12, the direction perpendicular to direction A, in which the bending line β of the conductive layer 111 (sheet member 120) extends, is defined as direction B. The direction perpendicular to both direction A and direction B is defined as direction C. In Figure 12, the first active material layer 12A is represented by hatching with diagonal lines.

[0088] In step S11, the first active material layer 12A is coated onto the outer surface 111E (the surface on the C1 side) of the conductive layer 111. The first active material layer 12A extends from the folding line β toward the B1 side and the B2 side, respectively. In other words, the first active material layer 12A extends in the B direction across the folding line β. The first active material layer 12A and the conductive layer 111 form a sheet member 120 that constitutes the first electrode 10A (Figure 8).

[0089] In this process, uncoated portions 120a and 120b are formed on the outer surface 111E of the conductive layer 111, where the first active material layer 12A is not applied. The uncoated portion 120a is formed at the B2 side end of the outer surface 111E. The uncoated portion 120b is formed at the B1 side end of the outer surface 111E. The uncoated portions 120a and 120b constitute an inner tab portion 91 (Figure 8) and an outer tab portion 92 (Figure 8), respectively, when the sheet member 120 is folded.

[0090] In step S11, a notch 123a is formed. The notch 123a extends in direction A along the bending line β. That is, the notch 123a forms a groove extending in direction A. The notch 123a may be formed by, for example, laser or cutting.

[0091] Figure 13 is a cross-sectional view taken in the direction of the arrow XIII-XIII in Figure 12. As shown in Figure 13, the notch 123a is formed by a first inclined surface 123c and a second inclined surface 123d facing each other in the direction of B. The first inclined surface 123c is inclined toward the conductive layer 111 side (C2 side) as it approaches the B2 side (second inclined surface 123d side). The second inclined surface 123d is inclined toward the conductive layer 111 side (C2 side) as it approaches the B1 side (first inclined surface 123c side). The first inclined surface 123c and the second inclined surface 123d are connected at the lower end 123e of the notch 123a.

[0092] The distance D between the first inclined surface 123c and the second inclined surface 123d decreases as it approaches the conductive layer 111 side (C2 side). The distance D decreases linearly as it approaches the conductive layer 111 side. The angle θ between the first inclined surface 123c and the second inclined surface 123d is preferably 90 degrees or more (for example, 120 degrees). The first active material layer 12A immediately after step S11 has a thickness t1 in the C direction.

[0093] Figure 14 shows the details of step S12 in Figure 11. The first active material layer 12A is pressed in the C direction by a press device 130. Specifically, the press device 130 includes a support base 131 and a pressing part 132. The support base 131 supports the sheet member 120 from the C2 side. The pressing part 132 presses the sheet member 120 supported by the support base 131 from the C1 side. By being pressed by the press device 130, the thickness of the first active material layer 12A in the C direction is reduced from thickness t1 (Figure 13) to thickness t2. Note that the C1 direction and C2 direction may be upward and downward, respectively.

[0094] In step S13, the insulating support layer 110 is pressed while it is not placed on the sheet member 120, which prevents the conductive layer 111 from becoming distorted (for example, curved) due to the shape (surface condition) of the insulating support layer 110.

[0095] Figure 15 shows the details of step S13 in Figure 11. In step S13, the inner surface 111D of the conductive layer 111 is subjected to corona treatment by a corona treatment machine 140. The inner surface 111D is surface-treated by corona discharge irradiation by the corona treatment machine 140. This modifies the inner surface 111D. As a result, the adhesion (bonding) between the inner surface 111D and the insulating support layer 110 is improved. Note that the corona treatment in step S13 is part of the "joining process" in this disclosure.

[0096] The corona treatment machine 140 may be configured to scan along the inner surface 111D. The corona treatment machine 140 may be configured to scan, for example, in direction B. The corona treatment machine 140 may also be configured to scan in direction A. This allows for easy corona treatment of the entire surface of the inner surface 111D. The sheet member 120 may also be moved in direction B (and direction A).

[0097] Figure 16 shows the details of step S14 in Figure 11. In step S14, the insulating support layer 110 is placed on the conductive layer 111 (sheet member 120). Specifically, the insulating support layer 110 is placed on the inner surface 111D of the conductive layer 111 that was corona-treated in step S13.

[0098] In Figure 16, the connection portion 111C (where it is planned to be formed) is shown by a dashed line. The insulating support layer 110 is positioned on one side in direction B (direction B1 in Figure 16) relative to the connection portion 111C.

[0099] Figure 17 shows the details of step S15 in Figure 11. In step S15, the sheet member 120 is bent so that the insulating support layer 110 is sandwiched between the inner portion 111A and the outer portion 111B of the conductive layer 111. For example, the inner portion 111A may be rotated to a position facing the outer portion 111B by bending the sheet member 120 with the connecting portion 111C as the pivot point. At this time, the sheet member 120 is bent so that a gap Ga is formed between the end portion 110C of the insulating support layer 110 and the connecting portion 111C.

[0100] Figure 18 shows the details of step S16 in Figure 11. In step S16, the insulating support layer 110 is pressed by the inner portion 111A and the outer portion 111B. This causes the inner surface 111D of the corona-treated conductive layer 111 to adhere closely to the inner surface 110A and the outer surface 110B of the insulating support layer 110. As a result, the inner portion 111A and the inner surface 110A are joined, and the outer portion 111B and the outer surface 110B are joined. Consequently, the insulating support layer 110 can be stably fixed to the conductive layer 111.

[0101] In Figure 18, the pressure applied by the press is indicated by block arrows. The press pressure in step S16 may be less than the press pressure in step S12. Furthermore, the same press device 130 (Figure 14) used in step S12 may also be used in step S16.

[0102] As described above, in this embodiment, by folding the conductive layer 111 (sheet member 120), the inner portion 111A is positioned on the inner surface 110A of the insulating support layer 110, the outer portion 111B is positioned on the outer surface 110B of the insulating support layer 110, and the connecting portion 111C is positioned opposite the end portion 110C of the insulating support layer 110. As a result, the first electrode 10A is formed. That is, by simply folding the conductive layer 111 (sheet member 120), the insulating support layer 110 can be wrapped by the conductive layer 111 (sheet member 120). As a result, the first electrode 10A can be easily formed. This simplifies the manufacturing process of the first electrode 10A compared to, for example, the case where the conductive layer positioned on the inner surface 110A and the conductive layer positioned on the outer surface 110B are formed separately. Therefore, the first electrode 10A, in which the conductive layer 111 is provided on both surfaces (110A, 110B) of the insulating support layer 110, can be efficiently manufactured.

[0103] Furthermore, since the inner portion 111A, the outer portion 111B, and the connecting portion 111C can be formed simply by bending the conductive layer 111, there is no need to use a vapor deposition apparatus or the like in the manufacture of the first electrode 10A. As a result, the manufacturing apparatus for the first electrode 10A can be simplified, and the manufacturing time for the first electrode 10A can be shortened by the time required for vapor deposition.

[0104] Furthermore, since the inner portion 111A and the outer portion 111B can be formed simply by bending the conductive layer 111, the manufacturing process can be simplified compared to the case where a single electrode foil is divided into one part for joining to the inner portion 111A and the other part for joining to the outer portion 111B.

[0105] <Variation> In the above embodiment, an example was shown in which a notch 123a is formed at a position along the folding line β of the first active material layer 12A, but the disclosure is not limited thereto. As shown in Figure 19, a hole 123f may be formed in the first active material layer 12A. Multiple holes 123f may be arranged along the folding line β. Multiple holes 123f may be arranged at equal intervals.

[0106] Figure 20 is a cross-sectional view taken in the direction of the arrow along the line XX-XX in Figure 19. As shown in Figure 20, the outer surface 111E of the conductive layer 111 is exposed at the location where the hole 123f is formed. Alternatively, the first active material layer 12A may be formed in the hole 123f. In this case, the thickness of the first active material layer 12A in the hole 123f is smaller than the thickness of the first active material layer 12A in other locations.

[0107] Alternatively, instead of multiple holes 123f, elongated holes extending in direction A may be formed.

[0108] In the above embodiment, an example was shown in which the first active material layer 12A is coated on the connection portion 111C of the conductive layer 111, but the disclosure is not limited thereto. As shown in Figure 21, an uncoated portion 124 may be formed on the connection portion 111C where the first active material layer 12A is not coated. That is, the inner active material portion 121 and the outer active material portion 122 may be separated by the uncoated portion 124.

[0109] As a result, the connection portion 111C is exposed to the atmosphere without being covered by the first active material layer 12A, thereby improving the heat dissipation efficiency of the connection portion 111C.

[0110] Although Figure 21 shows an example where the first active material layer 12A is not coated at all on the connection portion 111C, an uncoated portion may be formed only on a part of the connection portion 111C.

[0111] Figure 22 is a modified example of Figure 21. As shown in Figure 22, an insulating layer 124a may be formed on the uncoated portion 124. The insulating layer 124a may be provided over the entire area of ​​the uncoated portion 124. In this case, the insulating layer 124a is in contact with the inner active material portion 121 and the outer active material portion 122, respectively. The insulating layer 124a may be formed by solidifying an insulating slurry coated on the uncoated portion 124.

[0112] This makes it possible to suppress electrical conductivity between the positive and negative electrodes caused by contact between the connection portion 111C of the conductive layer 111 and the second electrode 10B (Figure 9).

[0113] In the above embodiment, an example was shown in which the connecting portion 111C is bent, but the disclosure is not limited thereto. For example, in the example shown in Figure 23, the inner portion 111A and the outer portion 111B are connected by a connecting portion 311C. The connecting portion 311C extends linearly along the thickness direction DT. A connecting active material portion 323 is arranged in the connecting portion 311C.

[0114] In the example shown in Figure 23, the corner 311A ​​of the conductive layer 311, where the inner portion 111A and the connecting portion 311C are connected, is bent. Similarly, the corner 311B of the conductive layer 311, where the outer portion 111B and the connecting portion 311C are connected, is also bent. As shown in Figure 23, a notch 323b is formed in the active material portion 323a provided at the corner 311A. Specifically, the notch 323b is formed on the outer surface 323c of the active material portion 323a opposite to the conductive layer 311. Note that the conductive layer 311 is an example of the "electrode foil" of this disclosure.

[0115] A notch 323e is formed in the active material portion 323d provided at the corner 311B. Specifically, a notch 323e is formed on the outer surface 323f of the active material portion 323d opposite to the conductive layer 111. A hole may be formed instead of the notches 323b and 323e. Furthermore, each of the active material portion 323a and the active material portion 323d is an example of the "bent portion coated portion" of this disclosure. Furthermore, each of the corners 311A ​​and 311B is an example of the "bent portion" of this disclosure. Furthermore, each of the outer surfaces 323c and 323f is an example of the "active material surface" of this disclosure.

[0116] In the above embodiment, an example is shown in which the conductive layer 111 is bent with the insulating support layer 110 placed on the conductive layer 111, but the disclosure is not limited thereto. The insulating support layer 110 may be inserted into the gap between the inner portion 111A and the outer portion 111B after the conductive layer 111 has been bent.

[0117] In the above embodiment, an example was shown in which the conductive layer 111 and the insulating support layer 110 are joined by corona treatment, but the disclosure is not limited thereto. The conductive layer 111 and the insulating support layer 110 may also be joined by adhesive or heat treatment (thermocompression bonding).

[0118] In the above embodiment, an example is shown in which the insulating support layer 110 is placed on the conductive layer 111 after the pressing process (S12), but the disclosure is not limited thereto. The pressing process may be performed after the insulating support layer 110 is placed on the conductive layer 111. In this case, the pressure from the pressing process may be used to bond the insulating support layer 110 and the corona-treated conductive layer 111.

[0119] In the above embodiment, an example was shown in which the inner tab portion 91 and the outer tab portion 92 of the conductive layer 111 are connected to the first connecting member 50A, but the disclosure is not limited thereto. A separate member different from the conductive layer 111 may be provided for connecting the conductive layer 111 and the first connecting member 50A.

[0120] The configurations of each of the above embodiments and each of the modified examples may be combined with each other.

[0121] 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]

[0122] 10 Electrode body, 10A First electrode (electrode sheet), 10B Second electrode, 11A First current collector, 12A First active material layer (active material layer), 50A First connecting member (current collector plate), 91 Inner tab portion (first protrusion), 92 Outer tab portion (second protrusion), 100 Energy storage cell, 110 Insulating support layer, 110A Inner surface (first surface), 110B Outer surface (second surface), 110C End, 111, 311 Conductive layer (electrode foil), 111A Inner portion (first portion), 111B Outer portion (second portion), 111C Connection portion (bent portion), 111D Inner surface (second main surface), 111E Outer surface (electrode surface) (first main surface), 120 Sheet member, 121 Inner active material portion (first active material portion), 122 Outer active material portion (second active material portion), 123 Connecting active material portion (bent coated portion), 123a, 323b, 323e Notches, 123b, 323c, 323f Outer surface (active material surface), 123f Hole, 124 Uncoated portion, 124a Insulating layer, 311A, 311B Corner portion (bent portion), 323a, 323d Active material portion (bent coated portion), Ga Gap.

Claims

1. A manufacturing process for an energy storage cell equipped with an electrode sheet, A forming step of forming a sheet member including an electrode foil having a first main surface and a second main surface, and an active material layer formed on the first main surface, A bending step of bending the sheet member, The process includes a placement step of placing the folded second main surface on the insulating support layer, The bending process is a process of forming a first portion, a second portion that is aligned with the first portion in the thickness direction of the insulating support layer, and a connecting portion that connects the first portion and the second portion on the electrode foil by bending the sheet member. If we define the direction that intersects the aforementioned thickness direction as the intersecting direction, A method for manufacturing an energy storage cell, comprising the bending step and the arrangement step, wherein either of these steps involves bringing a first surface provided at one end of the insulating support layer in the thickness direction into contact with the first portion, bringing a second surface of the insulating support layer opposite to the first surface into contact with the second portion, and aligning the end of the insulating support layer in the crossing direction with the connecting portion to form the electrode sheet.

2. The forming step is, A coating step of applying an active material layer to the first main surface, The process includes a pressing step of pressing the active material layer coated on the first main surface, The method for manufacturing an energy storage cell according to claim 1, wherein the arrangement step is performed after the pressing step.

3. A method for manufacturing an energy storage cell according to claim 1 or 2, further comprising the step of joining the first portion and the first surface, and the second portion and the second surface, respectively.

4. Current collector plate and The electrode body includes an electrode sheet connected to the current collector plate, The electrode sheet includes an insulating support layer, an electrode foil, and an active material layer formed on the electrode foil. The active material layer is positioned on the side of the electrode foil opposite to the insulating support layer. The electrode foil has a first portion and a second portion arranged in the thickness direction of the insulating support layer, and a connecting portion connecting the first portion and the second portion. The first portion is arranged on a first surface provided at one end of the insulating support layer in the thickness direction, The second portion is located on the second surface of the insulating support layer opposite to the first surface, If we define the direction that intersects the aforementioned thickness direction as the intersecting direction, The aforementioned connection portion is a storage cell that faces the end of the insulating support layer on the first direction side in the intersecting direction, with a gap in between, in the direction of the intersecting direction.

5. The electrode foil includes an electrode surface provided on the side opposite to the insulating support layer, The aforementioned active material layer is The electrode surface is coated, The first active material portion coated on the first portion, The second part comprises a second active material portion coated with the aforementioned second part, If the direction opposite to the first direction among the aforementioned intersecting directions is designated as the second direction, The first portion has a first projection that protrudes in the second direction more than the first active material portion in the intersecting direction, The second portion has a second projection that protrudes in the second direction more than the second active material portion in the intersecting direction, The energy storage cell according to claim 4, wherein at least one of the first protrusion and the second protrusion is connected to the current collector plate.

6. The energy storage cell according to claim 5, wherein an uncoated portion is formed in the connection portion where the active material layer is not coated.

7. The energy storage cell according to claim 6, wherein an insulating layer is formed on the uncoated portion.

8. The active material layer includes a bent portion coated on the bent portion of the electrode foil, The bent portion coated portion has an active material surface provided on the side opposite to the electrode foil, The energy storage cell according to any one of claims 5 to 7, wherein at least one of a hole and a notch is formed on the surface of the active material.

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