Energy storage cell and method for manufacturing an energy storage cell

Abstract

The present invention provides a power storage cell capable of suppressing the exposure of the insulating support layer due to crack formation in the conductive layer laminated on the insulating support layer. [Solution] The energy storage cell 100 comprises an electrode body 10 and a case 20 that houses the electrode body 10. The electrode body 10 includes a first electrode 10A. The first electrode 10A has an insulating support layer 110 and a first conductive layer 111 and a second conductive layer 112 formed on the insulating support layer 110. Each of the first conductive layer 111 and the second conductive layer 112 is formed of flaky metal powder 113.

Description

Technical Field

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

Background Art

[0002] Japanese Patent Application Laid-Open 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.

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, when the organic support layer (insulating support layer) is bent, there are cases where the conductive layer cannot follow the flexibility of the organic support layer. Specifically, when the conductive layer is bent together with the organic support layer, cracks may be formed in the conductive layer due to a gap being generated between the metal particles constituting the conductive layer. In this case, the organic support layer is exposed due to the formation of cracks. As a result, it is conceivable that the organic support layer expands or contracts due to gas permeating into the exposed organic support layer.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a storage battery cell and a method for manufacturing the storage battery cell that can suppress the exposure of an insulating support layer due to cracks being formed in a conductive layer laminated on the insulating support layer.

Means for Solving the Problems

[0006] A storage cell according to the first aspect of this disclosure comprises an electrode body and a housing for housing the electrode body. The electrode body includes an electrode sheet. The electrode sheet has an insulating support layer and a conductive layer formed on the insulating support layer. The conductive layer is formed of flake metal powder.

[0007] A method for manufacturing an energy storage cell according to the second aspect of this disclosure comprises the steps of forming an electrode body and housing the electrode body in a housing. The step of forming the electrode body includes the steps of preparing an insulating support layer and forming a conductive layer by laminating flake metal powder onto the insulating support layer. [Effects of the Invention]

[0008] According to this disclosure, it is possible to suppress the exposure of the insulating support layer due to the formation of cracks in the conductive layer laminated on the insulating support layer. [Brief explanation of the drawing]

[0009] [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 plan view showing the configuration of the first conductive layer. [Figure 7] This is a schematic cross-sectional view showing the configuration of the first conductive layer and the insulating support layer. [Figure 8] This is a flowchart illustrating the manufacturing method of the energy storage cell according to this embodiment. [Figure 9] This figure shows a method for forming a first conductive layer and a second conductive layer on an insulating support layer. [Figure 10]This is a schematic cross-sectional view showing the configuration of the conductive layer and insulating support layer according to a first modification of this embodiment. [Figure 11] This is a schematic cross-sectional view showing the configuration of the conductive layer and insulating support layer according to a second modification of this embodiment. [Modes for carrying out the invention]

[0010] 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.

[0011] 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).

[0012] 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.

[0013] 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.

[0014] The power storage device 1 includes a plurality of power storage stacks 3. Each power storage stack 3 is formed in a rectangular parallelepiped shape that is long in the Y direction. The plurality of power storage stacks 3 are arranged so as to line up along the X direction. Each power storage stack 3 includes a plurality of power storage cells 100 arranged in the Y direction. In FIG. 1, for the sake of simplicity, only two power storage stacks 3 are illustrated, and only three power storage cells 100 in each power storage stack 3 are illustrated.

[0015] FIG. 2 is a perspective view showing the power storage cell 100 according to the present embodiment. As shown in FIG. 2, the power storage cell 100 is a so-called square battery. The power storage cell 100 is a secondary battery configured to be capable of charging and discharging. The power storage cell 100 may be a secondary battery such as a lithium ion battery or a nickel hydrogen battery. The power storage cell 100 can be used, for example, as a cell included in a power storage module mounted on an electric vehicle.

[0016] The power storage 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 broken line.

[0017] The case 20 has conductivity. The conductive portion of the case 20 is made of a metal such as aluminum, for example. The case 20 houses the electrode body 10. The case 20 also houses an electrolytic solution (not shown). The case 20 is an example of the "housing body" of the present disclosure.

[0018] The case 20 includes a case main body 21 and a lid 22. The case main body 21 includes a bottom wall 210 and a peripheral wall 211 that stands up from the bottom wall 210.

[0019] The lid 22 includes a lid main body 220 and an insulating cover 221. The lid main 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] Figure 5 is a cross-sectional view of the first electrode 10A and the first tab 90A. The first current collector 11A includes an insulating support layer 110, a first conductive layer 111, and a second conductive layer 112. The first electrode 10A further includes a protective portion 13. Note that the first conductive layer 111 and the second conductive layer 112 are examples of the "conductive layers" of this disclosure.

[0047] 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 allows the rigidity of the first current collector 11A to be increased 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 approximately parallel to the Z direction. Note that the material of the insulating support layer 110 is not limited to the above example. For example, the insulating support layer 110 may be cloth or paper.

[0048] The first conductive layer 111 is formed on (in contact with) the insulating support layer 110 on one side in the thickness direction DT. The first conductive layer 111 is located on the winding axis α side (i.e., the inner circumference side) when viewed from the insulating support layer 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.

[0049] The second conductive layer 112 is formed on (in contact with) the insulating support layer 110 on the other side in the thickness direction DT. The second conductive layer 112 is located on the opposite side (i.e., the outer circumference side) from the winding axis α when viewed from the insulating support layer 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.

[0050] 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.

[0051] 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 insulating support layer 110 toward Z1.

[0052] 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 insulating support layer 110. Surface 14b is the surface of the second conductive layer 112 opposite to the insulating support layer 110.

[0053] 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.

[0054] 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 insulating support layer 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 insulating support layer 110 when viewed from the second conductive layer 112. The second foil portion 92 is bonded to the second conductive layer 112.

[0055] 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.

[0056] 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.

[0057] 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)).

[0058] 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)).

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] Figure 6 is a schematic plan view showing the surface of the first conductive layer 111. The structure of the second conductive layer 112 is identical to that of the first conductive layer 111. Therefore, in the following description, only the characteristics of the first conductive layer 111 will be explained in detail.

[0068] In conventional energy storage devices, when the insulating support layer is bent, the conductive layer may not be able to follow the flexibility of the insulating support layer. Specifically, when the conductive layer is bent together with the insulating support layer, gaps may form between the metal particles constituting the conductive layer, causing cracks to form in the conductive layer. In this case, the insulating support layer is exposed due to the formation of cracks. As a result, it is conceivable that the organic support layer may expand or contract due to gas penetration into the exposed insulating support layer.

[0069] Therefore, in this embodiment, the first conductive layer 111 is formed of flake metal powder (flake metal particles) 113. Specifically, the first conductive layer 111 is formed by stacking flake metal powder 113 on top of each other. The flake metal powder 113 is formed of, for example, aluminum particles.

[0070] Scale metal powder refers to metal particles with a larger aspect ratio than ordinary metal powder (hereinafter referred to as non-scale metal powder), which is different from scale metal powder. In this specification, the aspect ratio is defined as the value obtained by dividing the maximum diameter length r of the metal powder in a plan view (vertical in Figure 6) by the maximum thickness t of the metal powder (Figure 7). Since non-scale metal powder is approximately spherical, its aspect ratio is approximately 1. The maximum and minimum diameter lengths r of the scale metal powder 113 (horizontal in Figure 6) are each several tens of micrometers. The thickness t of the scale metal powder 113 is several micrometers. Therefore, the thickness of the scale metal powder 113 is a value greater than 1 (for example, 10). The diameter of non-scale metal powder is several nanometers.

[0071] Figure 7 shows a schematic cross-sectional view of the first conductive layer 111 and the insulating support layer 110. In Figure 7, the left-right direction is defined as the orthogonal direction DO, but the left-right direction may also be a direction perpendicular to the orthogonal direction DO and the thickness direction DT (i.e., the winding direction of the electrode body 10).

[0072] As shown in Figure 7, the flake metal powder 113 is a flat particle. Therefore, when the first electrode 10A is bent, even if a gap is created between adjacent flake metal powders 113 in a direction intersecting (orthogonal to) the stacking direction (for example, the orthogonal direction DO), the gap is easily covered by the flake metal powders 113 stacked across the other flake metal powders 113. As a result, it is possible to suppress the exposure of the insulating support layer 110 due to the formation of cracks in the first conductive layer 111.

[0073] This makes it possible to suppress the expansion or contraction of the insulating support layer 110 due to the penetration of gas into the insulating support layer 110. As a result, it is possible to suppress the peeling (detachment) of the first conductive layer 111 due to the release of the gas between the insulating support layer 110 and the first conductive layer 111.

[0074] As shown in Figure 7, adjacent flake metal powders 113 in the stacking direction (thickness direction DT) are more likely to be positioned offset from each other in a direction intersecting (orthogonal to) the stacking direction (orthogonal direction DO in Figure 7) compared to non-flake metal powders. As a result, pinholes are less likely to form in the first conductive layer 111.

[0075] <Manufacturing method for energy storage cells> Figure 8 shows a manufacturing flow diagram illustrating an example of a method for manufacturing the energy storage cell 100.

[0076] In step S1, the insulating support layer 110 is prepared. In step S1, a cleaning process may be performed on the surface of the insulating support layer 110. The cleaning may include, for example, at least one of the following: plasma treatment, corona treatment, UV treatment, static elimination treatment, adhesive roll treatment, and solvent treatment.

[0077] In step S2, a first conductive layer 111 and a second conductive layer 112 are formed on the insulating support layer 110. In step S3, an inner active material layer 121A is formed on the first conductive layer 111, and an outer active material layer 122A is formed on the second conductive layer 112. Steps S1 to S3 are included in the process of forming the first electrode 10A.

[0078] In step S4, the second electrode 10B is formed. In step S5, the first electrode 10A, the second electrode 10B, and the separator 10C are wound together. Steps S1 to S5 are included in the process of forming the electrode body 10.

[0079] In step S6, the electrode body 10, which was formed by winding in step S5, is housed in the case 20.

[0080] Figure 9 shows the process in step S2 of Figure 8. In step S2, the first conductive layer 111 and the second conductive layer 112 are formed by electrostatic coating. Note that the electrostatic coating in step S2 is performed in an atmospheric environment.

[0081] Specifically, paint particles 201 containing flake metal powder 113 are sprayed from a positively charged electrostatic spray gun 200 onto both surfaces of the insulating support layer 110. As a result, the flake metal powder 113 is deposited onto both surfaces of the insulating support layer 110, forming a first conductive layer 111 and a second conductive layer 112.

[0082] The insulating support layer 110 is supplied from a negatively charged roll 202 and passes through the region where paint particles 201 are sprayed by the electrostatic spray gun 200. Therefore, the insulating support layer 110 is negatively charged. As a result, paint particles 201 from the positively charged electrostatic spray gun 200 are sprayed onto the negatively charged insulating support layer 110.

[0083] As a result, the paint particles 201 are electrostatically attracted to the insulating support layer 110, which suppresses a decrease in the movement speed of the paint particles 201 as they move from the electrostatic spray gun 200 to the insulating support layer 110. Consequently, the paint particles 201 are more likely to be crushed and spread out on the surface of the insulating support layer 110. This makes it easy to orient the flaky metal powder 113 along the surface of the insulating support layer 110. Note that in Figure 9, (+) means positively charged and (-) means negatively charged.

[0084] The flaky metal powder 113 may also be formed by crushing metal foil. Alternatively, the flaky metal powder may be formed by rolling spherical particles, which serve as precursors, created by the atomization method, during the crushing process.

[0085] As described above, in the above embodiment, each of the first conductive layer 111 and the second conductive layer 112 formed on the insulating support layer 110 is formed of flake metal powder 113. This makes it possible to form a conductive layer in which the flake metal powder 113 is stacked alternately. As a result, the gaps between adjacent flake metal powder 113 can be covered by the flake metal powder 113 that is stacked across the other flake metal powder 113. This makes it possible to suppress the exposure of the insulating support layer 110.

[0086] Furthermore, in the above embodiment, the first electrode 10A constituting the wound electrode body 10 is arranged on both the inner and outer circumference sides of the insulating support layer 110. Here, because the electrode body 10 is wound, bending stress is easily applied to each of the first conductive layer 111 and the second conductive layer 112. As a result, gaps are easily created between adjacent flake metal powders 113. Therefore, using flake metal powders 113 is particularly effective in suppressing the exposure of the insulating support layer 110 in the wound electrode body 10.

[0087] <Variation> In the above embodiment, an example was shown in which the conductive layer formed on the insulating support layer 110 is formed solely of flake metal powder 113, but the disclosure is not limited thereto. In the example shown in Figure 10, a conductive layer 300 is formed on the insulating support layer 110 by laminating a conductive layer 111 and a conductive layer 310. The conductive layer 310 is positioned on the opposite side of the insulating support layer 110 from the conductive layer 111. The conductive layer 310 is formed of non-flake metal powder 311. As described above, the aspect ratio of the non-flake metal powder 311 is smaller than the aspect ratio of the flake metal powder 113. The conductive layer 112 may also be configured in the same way as in Figure 10. In the example shown in Figure 10, the conductive layer 111 and the conductive layer 310 are examples of the "first metal layer" and "second metal layer" of the disclosure, respectively.

[0088] Since the non-scalloped metal powder 311 is formed in a spherical shape, recesses 312 are formed between adjacent non-scalloped metal powders 311 on the outermost surface. As a result, the first active material layer 12A fits into the recesses 312, and the anchoring effect allows the first active material layer 12A to be more stably fixed to the conductive layer 300.

[0089] The conductive layer 300 may also be formed by first forming the conductive layer 111 on the insulating support layer 110 by electrostatic coating or the like, and then forming the conductive layer 310 on the conductive layer 111 by vapor deposition or sputtering.

[0090] In the example shown in Figure 11, a conductive layer 400, formed by laminating conductive layer 111 and conductive layer 310, is created on the insulating support layer 110. The conductive layer 310 is positioned on the insulating support layer 110 side relative to the conductive layer 111. The conductive layer 112 side may also be configured in the same way as in Figure 11.

[0091] Here, the conductive layer 111 has higher bending rigidity than the conductive layer 310 because the flake metal powder 113 extends along the insulating support layer 110. Therefore, the conductive layer 310, which has relatively low bending rigidity, is placed near the insulating support layer 110, and the conductive layer 310 is covered by the conductive layer 111. This makes the insulating support layer 110 easier to bend, and cracks formed in the conductive layer 310 can be covered by the conductive layer 111 (flake metal powder 113).

[0092] The conductive layer 400 may also be formed by first forming the conductive layer 310 on the insulating support layer 110 by vapor deposition or sputtering, and then forming the conductive layer 111 on the conductive layer 310 by electrostatic coating or the like.

[0093] In the above embodiment, an example was shown in which the first conductive layer 111 and the second conductive layer 112 have the same configuration, but the disclosure is not limited thereto. One conductive layer may have one of the configurations shown in Figures 7, 10, and 11, while the other conductive layer may have a different configuration from the one conductive layer shown in Figures 7, 10, and 11. Furthermore, a conductive layer may be formed only on one surface of the insulating support layer 110. In addition, a conductive layer formed of flake metal powder may be formed on the Z(DO) end face of the insulating support layer 110.

[0094] The above embodiment shows an example of forming a conductive layer by electrostatic coating using an electrostatic spray gun, but the disclosure is not limited thereto. For example, a paint containing flake metal powder may be applied to the insulating support layer 110 using a positively charged roll coat. Alternatively, the insulating support layer 110 may be immersed in a paint containing flake metal powder filled in a positively charged container.

[0095] In the above embodiment, an example was shown in which the first electrode 10A includes a conductive layer formed of flaky metal powder, but the disclosure is not limited thereto. In place of / in addition to the first electrode 10A, the second electrode 10B may include a conductive layer formed of flaky metal powder (for example, copper powder).

[0096] The above embodiment shows an example of forming a conductive layer by electrostatic coating, but the disclosure is not limited thereto. For example, paint particles containing flake metal powder may be sprayed from the spray gun onto the insulating support layer while the spray gun and the insulating support layer are not charged.

[0097] In the above embodiment, an example is shown in which the electrode body 10 is housed in the case 20, but the disclosure is not limited thereto. For example, the electrode body 10 may be housed (sealed) by a laminate film. In this case, the laminate film is an example of a "householding" in the disclosure.

[0098] The configurations of each of the above embodiments and each of the modified examples may be combined with each other.

[0099] 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]

[0100] 10 Electrode body, 10A First electrode (electrode sheet), 100 Energy storage cell, 110 Insulating support layer, 111 First conductive layer (conductive layer) (first metal layer), 112 Second conductive layer (conductive layer), 113 Flour metal powder, 300, 400 Conductive layer, 310 Conductive layer (second metal layer), 311 Non-flour metal powder, α Winding axis.

Claims

1. Electrode body and The system comprises a housing for housing the electrode body, The electrode body includes an electrode sheet, The electrode sheet is Insulating support layer, The insulating support layer has a conductive layer formed on it, The aforementioned conductive layer is formed of flaky metal powder, in an energy storage cell.

2. The electrode body is a wound electrode body in which the electrode sheet is wound around the winding axis, The energy storage cell according to claim 1, wherein the conductive layer is disposed on at least one of the inner and outer circumferential sides of the insulating support layer in the electrode sheet.

3. The conductive layer includes a stacked first metal layer and a second metal layer. The first metal layer is formed from the aforementioned metal flake powder, The second metal layer is formed of non-flaking metal powder, The energy storage cell according to claim 1 or 2, wherein the aspect ratio of the non-scalloped metal powder is smaller than the aspect ratio of the scalloped metal powder.

4. The process of forming an electrode body, The process includes the step of housing the electrode body in a housing, The step of forming the electrode body is: The process of preparing the insulating support layer, A method for manufacturing an energy storage cell, comprising the step of forming a conductive layer by laminating flake metal powder onto the insulating support layer.

5. The method for manufacturing an energy storage cell according to claim 4, wherein the step of forming the conductive layer is a step of laminating the flake metal powder onto the insulating support layer by electrostatic coating.

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