Electrode component

Abstract

The present invention provides an electrode member capable of suppressing the occurrence of wrinkles and bending in uncoated areas where the active material layer is not applied. [Solution] The electrode member 11A comprises a base material 100A including a resin base material 110 and conductive layers 121 and 122 formed on the resin base material 110, and active material layers 210A and 220A formed on the conductive layers 121 and 122, wherein the resin base material 110 has recesses 115 and 116 that are recessed inward in the thickness direction parallel to the stacking direction, at positions that overlap with the active material layers 210A and 220A in the stacking direction of the base material 100A and the active material layers 210A and 220A.

Description

Technical Field

[0001] This disclosure relates to an electrode member.

Background Art

[0002] As a conventional electrode body, Japanese Patent Application Laid-Open No. 2019-096592 (Patent Document 1) discloses an electrode member in which a conductive layer and an active material layer are laminated in this order on the surface of an insulating substrate on at least one of a sheet-like positive electrode member and a negative electrode member, and a separator is disposed between the positive electrode member and the negative electrode member, and these are wound. The conductive layer includes a first portion on which the active material layer is coated and a second portion protruding from the first portion, and through holes penetrating in the thickness direction are provided in the second portion and the portion of the insulating substrate corresponding to the second portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the manufacturing process of an electrode member, in order to fix the active material layer coated on a base material, there is a pressing process in which the active material layer and the base material are sandwiched between rollers and pressed. An uncoated region where the active material layer is not coated is formed on the base material. In the pressing process, the roller contacts the active material layer and does not contact the uncoated region. For this reason, in the base material, the coated region where the active material layer is coated extends due to pressing, but the uncoated region is less likely to extend, and a difference in extension may occur between the coated region and the uncoated region. When using a base material including a resin member, due to the above-described difference in extension, there is concern that the uncoated region may be curved or wrinkles may occur in the uncoated region.

[0005] This disclosure has been made in view of the above-mentioned problems, and the purpose of this disclosure is to provide an electrode member that can suppress the occurrence of wrinkles and bending in uncoated areas where the active material layer is not coated. [Means for solving the problem]

[0006] The electrode member according to this disclosure comprises a substrate including a resin substrate and a conductive layer formed on the resin substrate, and an active material layer formed on the conductive layer. The resin substrate has a recess that is recessed inward in the thickness direction parallel to the stacking direction, at a position that overlaps with the active material layer in the stacking direction of the substrate and the active material layer.

[0007] According to the above configuration, recesses are formed in the resin substrate in the stretchable region where the active material layer is formed, resulting in a thinner resin substrate and a thicker conductive layer. This allows for suppression of elongation in the stretchable region and a reduction in the difference in elongation between the stretchable and less stretchable regions where the active material layer is not formed, when the electrode member is pressed after coating with the active material layer. As a result, the occurrence of wrinkles and deformation into a curved shape in the less stretchable region where the active material layer is not formed can be suppressed.

[0008] In the electrode member according to the present disclosure described above, the recess may be provided such that its depth increases as it moves inward in the width direction perpendicular to the stacking direction.

[0009] According to the above configuration, the recess gradually deepens towards the center in the width direction, which allows for a gradual change in elongation in the width direction when the electrode member is pressed after the active material layer has been coated.

[0010] In the electrode member according to the present disclosure described above, both ends of the active material layer may be located inward from both ends of the recess in the width direction perpendicular to the lamination direction.

[0011] According to the above configuration, since the active material layer does not protrude in the width direction from the position of the recess, when the electrode member is pressed after coating with the active material layer, it is possible to more reliably suppress elongation in the region that is more prone to stretching and to suppress the difference in elongation between that region and the region that is less prone to stretching where the active material layer is not formed. [Effects of the Invention]

[0012] According to this disclosure, it is possible to provide an electrode member that can suppress the occurrence of wrinkles and bending in uncoated areas where the active material layer is not applied. [Brief explanation of the drawing]

[0013] [Figure 1] This is a perspective view of the battery according to Embodiment 1. [Figure 2] This is a disassembled perspective view of the battery according to Embodiment 1. [Figure 3] Figure 1 is a cross-sectional view of the battery as seen in the direction of the arrow III-III. [Figure 4] Figure 3 is a cross-sectional view of the electrode body as seen in the direction of the IV-IV line arrow. [Figure 5] This is a cross-sectional view of the first electrode member according to Embodiment 1. [Figure 6] This is a cross-sectional view of the first electrode member according to Embodiment 2. [Modes for carrying out the invention]

[0014] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and their descriptions will not be repeated.

[0015] (Embodiment 1) Figure 1 is a perspective view showing a battery according to Embodiment 1. As shown in Figure 1, the battery 1 according to Embodiment 1 is a so-called prismatic battery. Battery 1 may be a rechargeable secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. Battery 1 can be used, for example, as a cell included in an energy storage module mounted on an electric vehicle.

[0016] FIG. 2 is an exploded perspective view of the battery according to Embodiment 1. FIG. 3 is a cross-sectional view of the battery of FIG. 1 viewed in the direction of the arrow III-III. As shown in FIGS. 1 to 3, the battery 1 according to Embodiment 1 includes an electrode body 10, a case 20, a first external terminal 30A, a second external terminal 30B, a first connecting member 40A, a second connecting member 40B, a first sealing ring 50A, a second sealing ring 50B, a first terminal support portion 60A, a second terminal support portion 60B, an insulating member 70, and a fuse protection portion 80.

[0017] The case 20 has conductivity. The conductive portion of the case 20 is made of a metal such as aluminum. The case 20 houses the electrode body 10. The case 20 also houses an electrolyte (not shown).

[0018] The case 20 includes a case body 21 and a lid 22. The case body 21 includes a bottom wall 21a and a peripheral wall 21b standing up from the bottom wall 21a.

[0019] The bottom wall 21a includes a bottom main body 21aa, a pressure release valve 21ab, an outer protective film 21ac, and an inner protective film 21ad. The peripheral wall 21b stands up from the bottom main body 21aa. The pressure release valve 21ab is provided in the bottom main body 21aa. The outer protective film 21ac covers the pressure release valve 21ab from the outside. The inner protective film covers the pressure release valve 21ab from the inside. The bottom main body 21aa and the pressure release valve 21ab are made of a metal such as aluminum.

[0020] An opening is formed at the upper end of the peripheral wall 21b. The peripheral wall 21b has a substantially rectangular outer shape when viewed from the opening direction (the normal direction of the opening surface) of the opening. The opening and the bottom wall 21a are arranged in the first direction D1. The first direction D1 may be the height direction or the vertical direction of the battery 1. The peripheral wall 21b is made of a metal such as aluminum.

[0021] The lid 22 includes a lid body 22a, a sealing plug 22b, a plug cover 22c, and an insulating cover 22d.

[0022] The lid body 22a is joined to the peripheral wall 21b by welding or the like so as to close the opening in the peripheral wall 21b. The lid body 22a has a first connecting hole 22aa, a second connecting hole 22ab, and an electrolyte injection hole 22ac formed therein. The electrolyte injection hole 22ac is a through hole for injecting electrolyte into the case body 21 during the manufacturing process of the battery 1.

[0023] The sealing plug 22b seals the injection hole 22ac. The plug cover 22c covers the injection hole 22ac and the sealing plug 22b. The insulating cover 22d covers the injection hole 22ac, the sealing plug 22b, and the plug cover 22c.

[0024] The first external terminal 30A and the second external terminal 30B are provided so as to be exposed to the outside in the battery 1. The first connecting member 40A and the second connecting member 40B are conductive. At least a portion of the first connecting member 40A and the second connecting member 40B are located inside the case 20.

[0025] The first external terminal 30A or the first connecting member 40A is inserted through the first connecting hole 22aa. The first external terminal 30A and the first connecting member 40A are joined to each other. The first connecting member 40A is joined to the electrode body 10. As a result, the first external terminal 30A is electrically connected to the electrode body 10.

[0026] The second external terminal 30B or the second connecting member 40B is inserted through the second connecting hole 22ab. The second external terminal 30B and the second connecting member 40B are joined to each other. The second connecting member 40B is joined to the electrode body 10. As a result, the second external terminal 30B is electrically connected to the electrode body 10.

[0027] 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 second direction D2. The second direction D2 is perpendicular to the first direction D1.

[0028] The first seal ring 50A is provided along the first connecting hole 22aa. The first seal ring 50A is provided in the gap between the lid body 22a and the first external terminal 30A, and seals this gap. The second seal ring 50B is provided along the second connecting hole 22ab. The second seal ring 50B is provided in the gap between the lid body 22a and the second external terminal 30B, and seals this gap. The first seal ring 50A and the second seal ring 50B have electrical insulating properties.

[0029] The first terminal support portion 60A is locked to the lid body 22a. The first terminal support portion 60A supports the first external terminal 30A from the outer circumference of the first external terminal 30A. The first terminal support portion 60A includes a first locking ring 61A and a first covering ring 62A. The first locking ring 61A extends in an annular shape so as to surround the first connecting hole 22aa and is locked directly to the lid body 22a. The first covering ring 62A covers the first locking ring 61A. The first locking ring 61A supports the first external terminal 30A via the first covering ring 62A. The first covering ring 62A is made of a resin material that is electrically insulating or has relatively weak conductivity.

[0030] The second terminal support portion 60B is locked to the lid body 22a. The second terminal support portion 60B supports the second external terminal 30B from the outer circumference of the second external terminal 30B. The second terminal support portion 60B includes a second locking ring 61B and a second covering ring 62B. The second locking ring 61B extends in an annular shape so as to surround the second connecting hole 22ab and is locked directly to the lid body 22a. The second covering ring 62B covers the second locking ring 61B. The second locking ring 61B supports the second external terminal 30B via the second covering ring 62B. The second covering ring 62B is made of an electrically insulating resin material.

[0031] The insulating member 70 has electrical insulating properties. The insulating member 70 is placed between the plurality of electrode bodies 10 and the case 20. The insulating member 70 electrically insulates the plurality of electrode bodies 10 and the case 20 from each other. The insulating member 70 includes an insulating bracket 71, a circumferential insulating portion 72, and a bottom insulating portion 73.

[0032] The insulating bracket 71 is positioned between the multiple electrode bodies 10 and the lid body 22a. The insulating bracket 71 is relatively rigid and is in contact with both the electrode bodies 10 and the lid body 22a. As a result, the electrode bodies 10 are fixed to the case 20 in the first direction D1.

[0033] The circumferential insulating portion 72 is positioned between the multiple electrode bodies 10 and the circumferential wall 21b. The circumferential insulating portion 72 is made of a film-like material.

[0034] The bottom insulating portion 73 is positioned between each electrode body 10 and the bottom wall 21a. The bottom insulating portion 73 is made of a film-like material. In this embodiment, the bottom insulating portion 73 is adhered to the electrode body 10. Furthermore, the bottom insulating portion 73 covers only a portion of the bottom surface of the electrode body 10. However, the bottom insulating portion 73 may cover the entire bottom surface.

[0035] As shown in Figure 2, the battery 1 according to this embodiment comprises a plurality of electrode bodies 10. Typically, the battery 1 comprises two electrode bodies 10. These electrode bodies 10 are aligned in a third direction D3. The third direction D3 is perpendicular to both the first direction D1 and the second direction D2. 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.

[0036] The electrode body 10 is provided with a plurality of first tabs 150A and a plurality of second tabs 150B. One end of the plurality of first tabs 150A is connected to the first conductive layer 121 (see Figure 5) and the second conductive layer 122 (see Figure 5) of the first electrode member 11A (see Figure 4), which will be described later. The other end of the plurality of first tabs 150A is joined to the first connecting member 40A by ultrasonic welding or the like.

[0037] One end of each of the multiple second tabs 150B is connected to the second base material 100B of the second electrode member 11B (see Figure 4), which will be described later. The other end of each of the multiple second tabs 150B is joined to the second connecting member 40B mentioned above by ultrasonic welding or the like.

[0038] Figure 4 is a cross-sectional view of the electrode body of Figure 3, viewed in the direction of the IV-IV arrow. The electrode body 10 includes a first electrode member 11A, a second electrode member 11B, a separator 12, and a tape member 13. The electrode body 10 is wound so that the first electrode member 11A, the second electrode member 11B, and the separator 12 surround the winding axis Z. In this embodiment, the case where the electrode body 10 is a wound electrode body is described as an example, but it is not limited to this. The electrode body 10 may also be a laminated electrode body in which the first electrode member 11A, the second electrode member 11B, and the separator 12 are stacked in one direction (for example, a third direction D3). In Figure 4, the separator 12 is schematically shown by a dashed line.

[0039] The first electrode member 11A and the second electrode member 11B have a sheet-like outer shape. The electrode body 10 is constructed by winding the first electrode member 11A and the second electrode member 11B around one or more separators 12. The first electrode member 11A is, for example, the positive electrode, and the second electrode member 11B is the negative electrode.

[0040] The first electrode member 11A includes a first substrate 100A and a first active material layer 200A. The first active material layer 200A has the same polarity as the first electrode member 11A. The first active material layer 200A is, for example, a positive electrode active material layer. A known positive electrode active material layer can be used.

[0041] The first active material layer 200A is provided on both the front and back surfaces of the first substrate 100A. The detailed structure of the first substrate 100A will be described later with reference to Figure 5.

[0042] The second electrode member 11B includes a second substrate 100B and a second active material layer 200B. The second active material layer 200B has the same polarity as the second electrode member 11B. The second electrode member 11B is, for example, a negative electrode active material layer. Known materials can be used as the negative electrode active material layer.

[0043] The second substrate 100B is made of a metal member containing copper, such as copper foil. The second active material layer 200B is provided on the front and back surfaces of the second substrate 100B.

[0044] The separator 12 is provided between the first electrode member 11A and the second electrode member 11B. The separator 12 separates the first electrode member 11A and the second electrode member 11B while allowing ions to move between them. The ions are, for example, lithium ions. The separator 12 has electrical insulating properties.

[0045] In the electrode body 10, a separator 12 is located at the innermost circumference. Also, a separator 12 is located at the outermost circumference of the electrode body 10. In the winding direction DR, the outer edge of the separator 12 is fixed by a tape member 13 placed on the outer surface of the separator 12.

[0046] The separator 12 may contain, for example, a polyolefin resin. The separator 12 may be substantially made of a polyolefin resin. The polyolefin resin may contain, for example, at least one selected from the group consisting of polyethylene (PE) and polypropylene (PP).

[0047] Figure 5 is a cross-sectional view of the first electrode member according to Embodiment 1. Figure 5 shows a cross-sectional view of the first electrode member 11A in a cross section perpendicular to the second direction.

[0048] As shown in Figure 5, the first substrate 100A of the first electrode member 11A has a coated region R1 on which the first active material layer 200A is applied, and an uncoated region R2 on which the first active material layer 200A is not applied. In the first electrode member 11A, the first substrate 100A includes a first resin substrate 110 and a first conductive layer 121 and a second conductive layer 122 laminated on the first resin substrate 110.

[0049] The first resin substrate 110 has a first surface 111 and a second surface 112 in the thickness direction. The thickness direction is parallel to the lamination direction in which the first substrate 100A and the first active material layer 200A are laminated.

[0050] The first resin substrate 110 has recesses 115 and 116 that are recessed inward in the thickness direction, at least at positions overlapping with the first active material layer 200A in the lamination direction. Recess 115 is provided on the first surface 111 side. Recess 116 is provided on the second surface 112 side. Recesses 115 and 116 have a substantially U-shape. The bottom surfaces of recesses 115 and 116 are flat in a direction perpendicular to the thickness direction.

[0051] In the width direction of the first resin substrate 110, which is perpendicular to the thickness direction (the lamination direction described above), the widths of the recesses 115 and 116 are greater than the width of the first active material layer 200A. The width direction is parallel to the first direction in the electrode body 10. The recess 115 has both ends 115c and 115d in the width direction. The recess 116 has both ends 116c and 116d in the width direction.

[0052] The first resin substrate 110 may be made of a material with higher rigidity than the separator 12. The first resin substrate 110 is made of a resin composition including, for example, a polyamide resin, a polyester resin, or a polyolefin resin.

[0053] The first conductive layer 121 is formed on the first surface 111. More specifically, the first conductive layer 121 is formed on the recess 115 and on both outer sides of the recess 115 in the width direction on the first surface 111. On the first conductive layer 121, the surface opposite to the side where the first resin substrate 110 is located is provided to be substantially flat. The first conductive layer 121 formed on the recess 115 is thicker than the first conductive layer 121 formed on the first surface 111 on both outer sides of the recess 115.

[0054] The second conductive layer 122 is formed on the second surface 112. More specifically, the second conductive layer 122 is formed on the recess 116 and on the second surface 112 on both outer sides of the recess 116 in the width direction. In the second conductive layer 122, the surface on the side opposite to the side where the first resin substrate 110 is located is provided to be substantially flat. The second conductive layer 122 formed in the recess 116 is thicker than the second conductive layer 122 formed on the second surface 112 on both outer sides of the recess 116.

[0055] The first conductive layer 121 and the second conductive layer 122 are composed of a metal member containing aluminum. The first conductive layer 121 and the second conductive layer 122 may be formed on the first surface 111 and the second surface 112 by vapor deposition or the like. Alternatively, the first conductive layer 121 and the second conductive layer 122 may be composed of metal foil and bonded to the first surface 111 and the second surface 112 with an adhesive.

[0056] The first active material layer 200A is formed on the first conductive layer 121 and the second conductive layer 122. Specifically, the first active material layer 200A is formed on the first conductive layer 121 and the second conductive layer 122 at a position that overlaps with the recesses 115 and 116 in the stacking direction.

[0057] The first active material layer 200A has a first portion 210A and a second portion 220A. The first portion 210A is formed on the first conductive layer 121. The second portion 220A is formed on the second conductive layer 122. The first portion 210A has both ends 210c, 210d in the width direction, and the second portion 220A has both ends 220c, 220d in the width direction.

[0058] Both ends of the first active material layer 200A are located inward in the width direction compared to both ends of the recesses 115 and 116. Specifically, both ends 210c and 210d of the first portion 210A are located inward in the width direction compared to both ends 115c and 115d of the recess 115. Both ends 220c and 220d of the second portion 220A are located inward in the width direction compared to both ends 116c and 116d of the recess 116.

[0059] Generally, when fixing a coated active material layer onto a substrate, the active material layer and the substrate are sandwiched and pressed between a pair of rollers. During this pressing process, the substrate tends to stretch easily where it overlaps with the active material layer, and less easily in the uncoated areas where the active material layer has not yet formed.

[0060] In the first electrode member 11A according to Embodiment 1, the first resin substrate 110 has recesses 115 and 116 that are recessed in a thickness direction parallel to the lamination direction, at positions that overlap with the first active material layer 200A in the lamination direction.

[0061] Therefore, in the region overlapping with the first active material layer 200A in the lamination direction, the thickness of the first resin substrate 110 is reduced, while the thickness of the first conductive layer 121 and the second conductive layer 122 is increased. As a result, in the manufacturing process of the first electrode member 11A, when the first electrode member 11A is pressed after coating with the first active material layer 200A, elongation can be suppressed in the easily stretchable region, and the difference in elongation between the easily stretchable region and the less stretchable region where the first active material layer 200A is not formed can be suppressed. As a result, the occurrence of wrinkles and deformation into a curved shape can be suppressed in the less stretchable region where the first active material layer 200A is not formed.

[0062] Furthermore, in the width direction, both ends of the first active material layer 200A are located inward from both ends of the recesses 115 and 116. This prevents the first active material layer 200A from protruding from the recesses 115 and 116 in the width direction. As a result, when pressing the first electrode member 11A after coating the first active material layer 200A, elongation can be more reliably suppressed in areas that are more prone to elongation, and the difference in elongation between these areas and areas that are less prone to elongation where the first active material layer 200A is not formed can be suppressed.

[0063] (Embodiment 2) Figure 6 is a cross-sectional view of the first electrode member according to Embodiment 2. The first electrode member 11X according to Embodiment 2 will be described with reference to Figure 6.

[0064] As shown in Figure 6, the first electrode member 11X according to Embodiment 2 differs from the first electrode member 11 according to Embodiment 1 in the shape of the recesses 115X and 116X. The other configurations are substantially the same.

[0065] The recesses 115X and 116X are provided such that their depth increases as they move inward in the width direction, which is perpendicular to the lamination direction. The recesses 115X and 116X have a roughly V-shape. As a result, in the coated area R1, the thickness of the first resin substrate 110 gradually decreases as it moves towards the valleys of the recesses 115X and 116X.

[0066] Even in this configuration, the first electrode member 11X according to Embodiment 2 provides substantially the same effects as the first electrode member 11A according to Embodiment 1. Furthermore, the recesses 115X and 116X described above make it possible to gradually reduce the change in elongation of the first resin substrate 110 in the width direction in the coated area R1 when the first electrode member 11A is pressed after the first active material layer 200A has been coated.

[0067] (Other variations) In the embodiments 1 and 2 described above, the first electrode member 11A, which is the positive electrode, is described as an example in which the first base material 100A includes a first resin base material 110, a first conductive layer 121, and a second conductive layer 122, but the invention is not limited thereto. In the second electrode member 11B, which is the negative electrode, the second base material 100B may be configured in substantially the same way as the first base material 100A. That is, the second base material 100B may include a second resin base material and a conductive layer formed on the second resin base material. In this case, the conductive layer is made of a metal including copper. Furthermore, in the second resin base material, a recess (second recess) that is recessed inward in the thickness direction may be provided at a position that overlaps with the active material layer in the lamination direction in which the second resin base material and the conductive layer are laminated.

[0068] In the embodiments 1 and 2 described above, the first electrode member 11A is the positive electrode and the second electrode member 11B is the negative electrode are examples, but the invention is not limited to this. The first electrode member 11A may be the negative electrode and the second electrode member 11B may be the positive electrode. In this case, each component constituting the first electrode member 11A and the second electrode member 11B is selected to be suitable for the polarity of the substrate.

[0069] The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, and all modifications are within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0070] 1 Battery, 10 Electrode body, 11A, 11X First electrode member, 11B Second electrode member, 12 Separator, 13 Tape member, 20 Case, 21 Case body, 21a Bottom wall, 21aa Bottom body, 21ab Pressure relief valve, 21ad Inner protective film, 21b Peripheral wall, 22 Lid, 22a Lid body, 22aa First connecting hole, 22ab Second connecting hole, 22b Sealing plug, 22c Plug cover, 22d Insulating cover, 30A First external terminal, 30B Second external terminal, 40A First connecting member, 40B Second connecting member, 50A First sealing ring, 50B Second sealing ring, 60A First terminal support part, 60B Second terminal support part, 61A First locking ring, 61B Second locking ring, 62A First covering ring, 62B Second covering ring, 70 Insulating member, 71 Insulating bracket, 72 Peripheral insulating part, 73 Bottom insulating part, 80 Fuse protection part, 100A First base material, 100B Second base material, 110 First resin base material, 111 First surface, 112 Second surface, 115, 115X, 116, 116X Recesses, 115c, 115d, 116c, 116d, 210c, 210d, 220c, 220d Ends, 121 First conductive layer, 122 Second conductive layer, 150A First tab, 150B Second tab, 200A First active material layer, 200B Second active material layer, 210A First part, 220A Second part, D1 First direction, D2 Second direction, D3 Third direction, DR Winding direction, R1 Coated area, R2 Uncoated area, Z Winding axis.

Claims

1. A substrate comprising a resin substrate and a conductive layer formed on the resin substrate, The conductive layer comprises an active material layer formed on the conductive layer, The resin substrate has an electrode member having a recess that is recessed inward in the thickness direction parallel to the lamination direction, at a position that overlaps with the active material layer in the lamination direction of the substrate and the active material layer.

2. The electrode member according to claim 1, wherein the recess is provided such that its depth increases towards the inside in the width direction perpendicular to the stacking direction.

3. The electrode member according to claim 1 or 2, wherein in the width direction perpendicular to the lamination direction, both ends of the active material layer are located inward from both ends of the recess.

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