Wound electrode body

Abstract

The present disclosure is a wound electrode body. The wound electrode body is a wound electrode body in which a first electrode and a second electrode having a polarity different from that of the first electrode are wound apart by a separator in a flat shape. The wound electrode body includes: a first resin member wound around a winding axis; and a second resin member wound around the winding axis along the first resin member on the inner side of the first resin member. The linear expansion coefficient of the first resin member is greater than the linear expansion coefficient of the second resin member.

Description

Technical Field

[0001] This disclosure relates to wound electrode bodies. Background Technology

[0002] As a conventional wound electrode, Japanese Patent Application Publication No. 2019-096592 discloses a structure in which at least one of a sheet-like positive electrode and a negative electrode is used, which is formed by sequentially stacking a conductive layer and an active material layer on the surface of an insulating substrate, with a separator disposed between the positive electrode and the negative electrode, and the electrodes are wound together. The conductive layer includes a first portion coated with an active material layer and a second portion protruding from the first portion, and a through hole penetrating in the thickness direction is provided in the second portion and in the portion of the insulating substrate corresponding to the second portion. Summary of the Invention

[0003] In the case of a wound electrode body, when a resin substrate with conductive layers on both sides is used as the substrate to support the active material layer, there is a concern that the circumferential creep characteristics may deteriorate due to the resin substrate, resulting in winding relaxation.

[0004] This disclosure was made in view of the aforementioned problems, and the purpose of this disclosure is to provide a wound electrode body capable of suppressing winding slack.

[0005] The wound electrode body based on this disclosure is a flat wound electrode body in which a first electrode and a second electrode with a polarity different from the first electrode are wound together with a separator. This wound electrode body includes: a first resin member wound around a winding axis; and a second resin member wound around the winding axis along the first resin member inside the first resin member. The coefficient of linear expansion of the first resin member is greater than the coefficient of linear expansion of the second resin member.

[0006] According to the above configuration, the second resin member is disposed along the first resin member inside the first resin member. Furthermore, because the coefficient of linear expansion of the first resin member is greater than that of the second resin member, the first resin member is more prone to elongation than the second resin member, and the second resin member is more prone to shrinkage than the first resin member. Therefore, in the event of temperature changes, the elongation of the first resin member and the shrinkage of the second resin member cancel each other out, thus suppressing the loosening of the wound electrode body.

[0007] In the wound electrode body based on the present disclosure, the first electrode may include: a first substrate having the first resin member and a first conductive layer formed on the first resin member; and a first active material layer formed on the first conductive layer. The second electrode may include: a second substrate having the second resin member and a second conductive layer formed on the second resin member; and a second active material layer formed on the second conductive layer.

[0008] According to the above configuration, in the configuration where both the first electrode and the second electrode contain resin components, it is possible to suppress the slack of the winding of the wound electrode body.

[0009] In the above-described wound electrode body based on the present disclosure, the first electrode may include a first substrate and a first active material layer. The first substrate has a resin substrate on which the first resin member and the second resin member are stacked and a first conductive layer formed on the resin substrate. The first active material layer is formed on the first conductive layer.

[0010] According to the above configuration, in the configuration where the first electrode includes a resin substrate having the first resin member and the second resin member stacked on it, the winding slack of the wound electrode body can be suppressed.

[0011] In the wound electrode body based on the present disclosure, the resin substrate has an overlapping region that overlaps with the first active material layer and a non-overlapping region that does not overlap with the first active material layer in the stacking direction of the first resin member and the second resin member. The proportion of the second resin member in the stacking direction in the overlapping region can be greater than the proportion of the second resin member in the stacking direction in the non-overlapping region.

[0012] Generally, in the manufacture of electrodes, a pressing process is used to press the active material layer and the substrate together using a pair of rollers in order to fix the active material layer onto the substrate. During the pressing process, the overlapping area of ​​the substrate that overlaps with the active material layer is clamped by the pair of rollers, thus making it easy to elongate.

[0013] According to the above configuration, the second resin member is less prone to elongation than the first resin member, and the proportion of the second resin member increases in the overlapping region, thereby suppressing the elongation of the resin substrate in the overlapping region. This, in turn, suppresses the peeling of the first active material layer associated with the elongation of the resin substrate.

[0014] In the wound electrode body based on the present disclosure, the first resin component may comprise polyethylene. The second resin component may comprise polypropylene.

[0015] Based on the above structure, the different coefficients of linear expansion of polyethylene and polypropylene can suppress the slack of the winding electrode body.

[0016] According to this disclosure, a wound electrode body capable of suppressing winding slack can be provided. Attached Figure Description

[0017] The exemplary embodiments of the present invention, its features, advantages, technical advancements, and industrial significance are described below with reference to the accompanying drawings, wherein like reference numerals denote like elements, wherein:

[0018] Figure 1 This is a perspective view of the battery according to Embodiment 1;

[0019] Figure 2 This is an exploded perspective view of the battery according to Embodiment 1;

[0020] Figure 3 Observe in the direction of the arrow on line III-III Figure 1 A cross-sectional view of the battery;

[0021] Figure 4 Observe in the direction of the arrow on line IV-IV. Figure 3 A cross-sectional view of the wound electrode body;

[0022] Figure 5A This is a cross-sectional view with the first electrode according to Embodiment 1 unfolded.

[0023] Figure 5B This is a cross-sectional view with the second electrode according to Embodiment 1 unfolded.

[0024] Figure 6A This is a cross-sectional view with the first electrode according to Embodiment 2 unfolded.

[0025] Figure 6B This is a cross-sectional view with the second electrode according to Embodiment 2 unfolded.

[0026] Figure 7 This is a cross-sectional view with the first electrode according to Embodiment 3 unfolded. Detailed Implementation

[0027] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. Furthermore, in the embodiments shown below, the same or common parts are labeled with the same reference numerals in the drawings and will not be described again.

[0028] Implementation Method 1

[0029] Figure 1 This is a perspective view showing the battery according to Embodiment 1. (e.g.) Figure 1 As shown, the battery 1 involved in the embodiment is a so-called prismatic battery. Battery 1 can be a secondary battery, such as a lithium-ion battery or a nickel-metal hydride battery, configured to be rechargeable and dischargeable. Battery 1 can be used, for example, as a single cell included in an energy storage module mounted in an electric vehicle.

[0030] Figure 2 This is an exploded perspective view of the battery involved in Embodiment 1. Figure 3 Observe in the direction of the arrow on line III-III Figure 1A cross-sectional view of the battery. (e.g.) Figures 1 to 3 As shown, the battery 1 according to Embodiment 1 includes a wound electrode body 10, a housing 20, a first external terminal 30A, a second external terminal 30B, a first connecting structure 40A, a second connecting structure 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.

[0031] The housing 20 is conductive. The conductive parts within the housing 20 are made of a metal such as aluminum. The housing 20 houses the wound electrode body 10. The housing 20 also houses an electrolyte (not shown).

[0032] The housing 20 includes a housing body 21 and a cover 22. The housing body 21 includes a bottom wall 21a and a peripheral wall 21b rising from the bottom wall 21a.

[0033] The bottom wall 21a includes a bottom body 21aa, a pressure relief valve 21ab, an outer protective membrane 21ac, and an inner protective membrane 21ad. The peripheral wall 21b rises from the bottom body 21aa. The pressure relief valve 21ab is disposed on the bottom body 21aa. The outer protective membrane 21ac covers the pressure relief valve 21ab from the outside. The inner protective membrane 21ad covers the pressure relief valve 21ab from the inside. The bottom body 21aa and the pressure relief valve 21ab are made of metal such as aluminum.

[0034] An opening is formed at the upper end of the peripheral wall 21b. The peripheral wall 21b has a generally rectangular shape when viewed from the opening direction (the normal direction of the opening surface). The opening and the bottom wall 21a are aligned in a first direction D1. The first direction D1 can be the height direction of the battery 1 or the vertical direction. The peripheral wall 21b is made of a metal such as aluminum.

[0035] The cover 22 includes a cover body 22a, a sealing plug 22b, a plug cover 22c, and an insulating cover 22d.

[0036] The cover body 22a is joined to the peripheral wall 21b by welding or the like, in a manner that blocks the opening of the peripheral wall 21b. A first connecting hole 22aa, a second connecting hole 22ab, and an electrolyte injection hole 22ac are formed on the cover body 22a. The electrolyte injection hole 22ac is a through hole for injecting electrolyte into the casing body 21 during the manufacturing process of the battery 1.

[0037] The sealing plug 22b seals the injection hole 22ac. The plug cap 22c covers the injection hole 22ac and the sealing plug 22b. The insulating cap 22d covers the injection hole 22ac, the sealing plug 22b, and the plug cap 22c.

[0038] The first external terminal 30A and the second external terminal 30B are arranged to be exposed to the outside in the battery 1. The first connecting structural member 40A and the second connecting structural member 40B are conductive. At least a portion of the first connecting structural member 40A and the second connecting structural member 40B is disposed inside the housing 20.

[0039] The first external terminal 30A or the first connecting member 40A is inserted into the first connecting hole 22aa. The first external terminal 30A and the first connecting member 40A are engaged with each other. The first connecting member 40A is engaged with the wound electrode body 10. Thus, the first external terminal 30A is electrically connected to the wound electrode body 10.

[0040] The second external terminal 30B or the second connecting member 40B is inserted into the second connecting hole 22ab. The second external terminal 30B and the second connecting member 40B are engaged with each other. The second connecting member 40B is engaged with the wound electrode body 10. Thus, the second external terminal 30B is electrically connected to the wound electrode body 10.

[0041] Furthermore, 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 arranged in the second direction D2. The second direction D2 is a direction orthogonal to the first direction D1.

[0042] A first sealing ring 50A is disposed along the first connecting hole 22aa. The first sealing ring 50A is disposed in the gap between the cover body 22a and the first external terminal 30A, sealing the gap. A second sealing ring 50B is disposed along the second connecting hole 22ab. The second sealing ring 50B is disposed in the gap between the cover body 22a and the second external terminal 30B, sealing the gap. The first sealing ring 50A and the second sealing ring 50B are electrically insulating.

[0043] The first terminal support portion 60A is engaged with the cover body 22a. The first terminal support portion 60A supports the first external terminal 30A from its outer periphery. The first terminal support portion 60A includes a first locking ring 61A and a first covering ring 62A. The first locking ring 61A extends annularly around the first connecting hole 22aa and is directly engaged with the cover 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 member having electrical insulation or relatively weak conductivity.

[0044] The second terminal support 60B is engaged with the cover body 22a. The second terminal support 60B supports the second external terminal 30B from its outer periphery. The second terminal support 60B includes a second locking ring 61B and a second covering ring 62B. The second locking ring 61B extends annularly around the second connecting hole 22ab and is directly engaged with the cover 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 component.

[0045] The insulating member 70 is electrically insulating. The insulating member 70 is disposed between the plurality of wound electrode bodies 10 and the housing 20. The insulating member 70 electrically insulates the plurality of wound electrode bodies 10 and the housing 20 from each other. The insulating member 70 includes an insulating support 71, a peripheral insulating portion 72, and a bottom insulating portion 73.

[0046] An insulating bracket 71 is disposed between the plurality of wound electrode bodies 10 and the cover 22a. The insulating bracket 71 has high rigidity and is in contact with both the wound electrode bodies 10 and the cover 22a. Thus, the wound electrode bodies 10 are fixed in the housing 20 in the first direction D1.

[0047] The peripheral insulating portion 72 is disposed between the plurality of wound electrode bodies 10 and the peripheral wall 21b. The peripheral insulating portion 72 is composed of a film-like component.

[0048] A bottom insulating portion 73 is disposed between each wound electrode body 10 and the bottom wall 21a. The bottom insulating portion 73 is composed of a film-like component. In this embodiment, the bottom insulating portion 73 is bonded to the wound electrode body 10. Alternatively, the bottom insulating portion 73 may only cover a portion of the bottom surface of the wound electrode body 10. Furthermore, the bottom insulating portion 73 may also cover the entire bottom surface.

[0049] like Figure 2 As shown, the battery 1 according to this embodiment includes a plurality of wound electrode bodies 10. Typically, the battery 1 includes two wound electrode bodies 10. These wound electrode bodies 10 are arranged in a third direction D3. The third direction D3 is a direction orthogonal to both the first direction D1 and the second direction D2. Furthermore, the peripheral insulating portion 72 can integrally cover the plurality of wound electrode bodies 10 in a manner that fixes them together.

[0050] A plurality of first electrode tabs 151 and a plurality of second electrode tabs 152 are provided on the wound electrode body 10. One end of the plurality of first electrode tabs 151 is connected to the first electrode 11 described later (see reference). Figure 4 The first conductive layer 111, 112 (refer to) Figure 5A , Figure 5BThe other end of the plurality of first tabs 151 is joined to the aforementioned second connecting structure 40B by means of ultrasonic welding or the like.

[0051] One end of the plurality of second electrodes 152 is connected to the second electrode 12 described later (see reference). Figure 4 The second conductive layers 121 and 122 (refer to) Figure 6A , Figure 6B The other end of the plurality of second tabs 152 is joined to the first connecting structural member 40A described above by means of ultrasonic welding or the like.

[0052] Figure 4 Observe from the direction of the arrow on line IV-IV Figure 3 A cross-sectional view of the wound electrode body. The wound electrode body 10 includes a first electrode 11, a second electrode 12, a diaphragm 13, and a tape member 14. In the wound electrode body 10, the first electrode 11, the second electrode 12, and the diaphragm 13 are wound around the winding axis Z. Furthermore, in Figure 4 In the diagram, diaphragm 13 is schematically represented by a dashed line.

[0053] The first electrode 11 and the second electrode 12 have a sheet-like shape. The wound electrode body 10 is constructed by winding the first electrode 11 and the second electrode 12 with one or more diaphragms 13 in between. For example, the first electrode 11 is the negative electrode and the second electrode 12 is the positive electrode.

[0054] The first electrode 11 includes a first substrate 101 and a first active material layer 115. The first active material layer 115 has the same polarity as the first electrode 11. The first active material layer 115 is, for example, a negative electrode active material layer. As the negative electrode active material layer, a known negative electrode active material layer can be used. The first active material layer 115 is disposed on the surface and back surface of the first substrate 101.

[0055] The second electrode 12 includes a second substrate 102 and a second active material layer 125. The second active material layer 125 has the same polarity as the second electrode 12. The second active material layer 125 is, for example, a positive electrode active material layer. As the positive electrode active material layer, a known positive electrode active material layer can be used. The second active material layer 125 is disposed on the surface and back surface of the second substrate 102.

[0056] Furthermore, the detailed structures of the first substrate 101 and the second substrate 102 will be discussed later. Figure 5A , Figure 5B To describe.

[0057] A separator 13 is disposed between the first electrode 11 and the second electrode 12. The separator 13 enables the exchange of ions between the first electrode 11 and the second electrode 12, and separates the first electrode 11 and the second electrode 12. The ions are, for example, lithium ions. The separator 13 is electrically insulating.

[0058] In the wound electrode body 10, the diaphragm 13 is located on the innermost peripheral side. Additionally, in the wound electrode body 10, the diaphragm 13 is also located on the outermost peripheral side. The outer peripheral edge of the diaphragm 13 in the winding direction DR is fixed by a belt member 14 disposed on the outer peripheral surface of the diaphragm 13.

[0059] The diaphragm 13 may comprise, for example, a polyolefin resin. The diaphragm 13 may be substantially composed of a polyolefin resin. The polyolefin resin may, for example, comprise at least one selected from polyethylene (PE) and polypropylene (PP).

[0060] Figure 5A , Figure 5B This is a cross-sectional view with the first electrode and the second electrode according to Embodiment 1 unfolded. Figure 5A This is a cross-sectional view of the first electrode. Figure 5B This is a cross-sectional view of the second electrode. Furthermore, Figure 5A , Figure 5B It is a cross section orthogonal to the thickness direction of each electrode.

[0061] like Figure 5A As shown, the first substrate 101 of the first electrode 11 includes a first resin member 110 and a first conductive layer 111, 112 formed on the first resin member 110.

[0062] The first resin component 110 has a first surface 110a and a second surface 110b in the thickness direction. Furthermore, the thickness direction is parallel to the stacking direction of the first substrate 101 and the first active material layer 115. The coefficient of linear expansion of the first resin component 110 is greater than that of the second resin component 120, which will be described later.

[0063] A first conductive layer 111 is formed on a first surface 110a, and a first conductive layer 112 is formed on a second surface 110b. The first conductive layers 111 and 112 are constructed using a metal component containing copper. The first conductive layers 111 and 112 can be formed on the first surface 110a and the second surface 110b by means of vapor deposition or the like. Alternatively, the first conductive layers 111 and 112 can also be constructed of metal foil and bonded to the first surface 110a and the second surface 110b using an adhesive.

[0064] The first active material layer 115 is formed on the first conductive layers 111 and 112. Specifically, the first active material layer 115 is formed on the central portion of the first conductive layers 111 and 112 in the width direction.

[0065] The first active material layer 115 includes a first portion 113 and a second portion 114. The first portion 113 is formed on the first conductive layer 111. The second portion 114 is formed on the first conductive layer 112.

[0066] like Figure 5B As shown, the second substrate 102 of the second electrode 12 includes a second resin member 120 and second conductive layers 121 and 122 formed on the second resin member 120.

[0067] The second resin component 120 has a first surface 120a and a second surface 120b in the thickness direction. Furthermore, the thickness direction is parallel to the stacking direction of the second substrate 102 and the second active material layer 125.

[0068] A second conductive layer 121 is formed on the first surface 120a, and a second conductive layer 122 is formed on the second surface 120b. The second conductive layers 121 and 122 are constructed using a metal component containing copper. The second conductive layers 121 and 122 can be formed on the first surface 120a and the second surface 120b by means of vapor deposition or the like. Alternatively, the second conductive layers 121 and 122 can also be constructed of metal foil and bonded to the first surface 120a and the second surface 120b using an adhesive.

[0069] The second active material layer 125 is formed on the second conductive layers 121 and 122. Specifically, the second active material layer 125 is formed on the central portion of the second conductive layers 121 and 122 in the width direction.

[0070] The second active material layer 125 includes a first portion 123 and a second portion 124. The first portion 123 is formed on the second conductive layer 121. The second portion 124 is formed on the second conductive layer 122.

[0071] like Figures 4 to 6B As shown, in the wound electrode body 10, the first resin member 110 is wound around the winding axis Z, and the second resin member 120 is wound along the winding axis Z on the inner side of the first resin member 110.

[0072] In addition, as described above, the coefficient of linear expansion of the first resin component 110 is greater than that of the second resin component 120. The first resin component 110 is more prone to elongation than the second resin component 120, and the second resin component 120 is more prone to shrinkage than the first resin component 110.

[0073] Therefore, when a temperature change occurs, the elongation of the first resin component 110 and the shrinkage of the second resin component 120 cancel each other out, which can suppress the slack of the winding of the winding electrode body.

[0074] Furthermore, as an example of a resin component where the coefficient of linear expansion of the first resin component 110 is greater than that of the second resin component 120, the case in which the first resin component 110 is polyethylene and the second resin component 120 is polypropylene can be given, but it is not limited to this case as long as the above-mentioned relationship between the coefficients of linear expansion is satisfied.

[0075] The coefficient of linear expansion of both the first resin component 110 and the second resin component 120 can be positive. However, when the coefficient of linear expansion of the first resin component 110 is positive and the coefficient of linear expansion of the second resin component 120 is negative, the effect of offsetting elongation and shrinkage as described above can be significantly achieved.

[0076] Implementation Method 2

[0077] Figure 6A , Figure 6B This is a cross-sectional view with the first and second electrodes according to Embodiment 2 unfolded. Figure 6A This is a cross-sectional view of the first electrode. Figure 6B This is a cross-sectional view of the second electrode.

[0078] like Figure 6A , Figure 6B As shown, the wound electrode body according to Embodiment 2 differs from the wound electrode body 10 according to Embodiment 1 in the configuration of the first substrate 101A and the second substrate 102A. The other configurations are substantially the same.

[0079] The first substrate 101A of the first electrode 11A includes a first resin substrate 110A and first conductive layers 111 and 112. The first resin substrate 110A includes a first resin member 117 and a second resin member 118. The first resin member 117 and the second resin member 118 are stacked in the thickness direction of the first resin substrate 110A. The first resin member 117 and the second resin member 118 have a flat plate shape.

[0080] In the wound electrode body, the first resin member 117 is located on the outer side, and the second resin member 118 is located on the inner side. That is, in the wound electrode body, the second resin member 118 is wound around the winding axis Z along the first resin member 117 on the inner side of the first resin member 117.

[0081] The first resin substrate 110A has a first surface 110a and a second surface 110b in the thickness direction. The first surface 110a is formed by a second resin member 118, and the second surface 110b is formed by a first resin member 117.

[0082] A first conductive layer 111 is formed on the first surface 110a. A first conductive layer 112 is formed on the second surface 110b. A first active material layer 115 is formed on the first conductive layers 111 and 112, respectively.

[0083] The second substrate 102A of the second electrode 12A includes a second resin substrate 120A and second conductive layers 121 and 122. The second resin substrate 120A includes a third resin component 127 and a fourth resin component 128. The third resin component 127 and the fourth resin component 128 are stacked in the thickness direction of the second resin substrate 120A. The third resin component 127 and the fourth resin component 128 have a flat plate shape.

[0084] In the wound electrode body, the third resin member 127 is located on the outer side, and the fourth resin member 128 is located on the inner side. That is, in the wound electrode body, the fourth resin member 128 is wound around the winding axis Z along the third resin member 127 on the inner side of the third resin member 127.

[0085] The second resin substrate 120A has a first surface 120a and a second surface 120b in the thickness direction. The first surface 120a is formed by a fourth resin member 128, and the second surface 120b is formed by a third resin member 127.

[0086] A second conductive layer 121 is formed on the first surface 120a. A second conductive layer 122 is formed on the second surface 120b. A second active material layer 125 is formed on the second conductive layers 121 and 122, respectively.

[0087] In Embodiment 2, on the side of the first electrode 11A, the coefficient of linear expansion of the first resin member 117 is greater than that of the second resin member 118. The first resin member 117 is more prone to elongation than the second resin member 118, and the second resin member 118 is more prone to shrinkage than the first resin member 117.

[0088] Thus, similar to Embodiment 1, when a temperature change occurs, the elongation of the first resin member 117 and the shrinkage of the second resin member 118 cancel each other out, which can suppress the slack of the winding of the winding electrode body.

[0089] In addition, on the side of the second electrode 12A, the coefficient of linear expansion of the third resin member 127 is greater than that of the fourth resin member 128. The third resin member 127 is more prone to elongation than the fourth resin member 128, and the fourth resin member 128 is more prone to shrinkage than the third resin member 127.

[0090] Therefore, on the second electrode 12A side, when a temperature change occurs, the elongation of the third resin member 127 and the contraction of the fourth resin member 128 cancel each other out, which can more effectively suppress the winding slack of the wound electrode body.

[0091] Furthermore, as an example of the first resin component 117 and the second resin component 118, the first resin component 117 may be made of polyethylene and the second resin component 118 may be made of polypropylene, but it is not limited to this as long as the above-mentioned relationship of the coefficient of linear expansion is satisfied.

[0092] Similarly, as an example of the third resin component 127 and the fourth resin component 128, it is possible that the third resin component 127 is polyethylene and the fourth resin component 128 is polypropylene, but it is not limited to this as long as the above-mentioned relationship of the coefficient of linear expansion is satisfied.

[0093] Implementation Method 3

[0094] Figure 7 This is a cross-sectional view with the first electrode according to Embodiment 3 unfolded. (Refer to...) Figure 7 The first electrode 11B according to Embodiment 3 will be described.

[0095] like Figure 7 As shown, the first electrode 11B according to Embodiment 3 differs from the first electrode 11A according to Embodiment 2 in the composition of the first resin substrate 110B, and specifically the shapes of the first resin member 117 and the second resin member 118. Other configurations are substantially the same.

[0096] The first resin substrate 110B has an overlapping region R1 that overlaps with the first active material layer 115 and a non-overlapping region R2 that does not overlap with the first active material layer 115 in the lamination direction of the first resin member 117 and the second resin member 118. In the first resin substrate 110B, the overlapping region R1 is located on the central side in the width direction. The non-overlapping regions R2 are located on both outer sides of the overlapping region R1 in the width direction.

[0097] The first resin member 117 has a shape in which the central portion is recessed toward the second surface 110b in the aforementioned width direction. The second resin member 118 has a shape in which the central portion is bulging toward the second surface 110b in the aforementioned width direction.

[0098] In the overlapping region R1, the proportion of the second resin component 118 in the aforementioned lamination direction is greater than the proportion of the second resin component 118 in the aforementioned lamination direction in the non-overlapping region R2.

[0099] The proportion of the second resin component 118 in the overlapping region R1 is greater than the proportion of the first resin component 117 in the overlapping region R1. The proportion of the second resin component 118 in the non-overlapping region R2 is less than the proportion of the first resin component 117 in the overlapping region R1.

[0100] Even in the configuration described above, the same effect as that of the winding electrode in Embodiment 2 can be obtained in the wound electrode body having the first electrode 11B according to Embodiment 3.

[0101] Furthermore, in the overlapping region R1, the proportion of the second resin member 118, which is less prone to elongation than the first resin member 117, increases. Therefore, when the first active material layer 115 and the first substrate 101B are pressed together using a pair of rollers during electrode manufacturing, the elongation of the first resin substrate 110B in the overlapping region R1 can be suppressed. This, in turn, suppresses the peeling of the first active material layer 115 that accompanies the elongation of the first resin substrate 110B.

[0102] Furthermore, in Embodiment 3, on the second electrode side, the third resin member 127 and the fourth resin member 128 may also have the same relationship as the first resin member 117 and the second resin member 118 described above. That is, the third resin member 127 may have a shape in which the central portion is recessed toward the second surface 120b in the aforementioned width direction, and the fourth resin member 128 may have a shape in which the central portion is bulging toward the second surface 120b in the aforementioned width direction.

[0103] In the overlapping region where the second resin substrate and the second active material layer 125 overlap, the proportion of the fourth resin component 128 in the aforementioned lamination direction can be greater than the proportion of the fourth resin component 128 in the aforementioned lamination direction in the non-overlapping region where the second resin substrate does not overlap with the second active material layer 125.

[0104] Furthermore, the proportion of the fourth resin component 128 in the overlapping region of the second resin substrate may be greater than the proportion of the third resin component 127 in the overlapping region. The proportion of the fourth resin component 128 in the non-overlapping region of the second resin substrate may be less than the proportion of the third resin component 127 in the overlapping region.

[0105] Other variations

[0106] In the embodiments 1 to 3 described above, the case where the first electrode 11 is a negative electrode and the second electrode is a positive electrode has been illustrated, but the description is not limited to this. The first electrode 11 may also be a positive electrode and the second electrode a negative electrode. In this case, each component constituting the first electrode 11 and the second electrode 12 may be a component with a polarity suitable for the substrate.

[0107] In embodiments 1 to 3 described above, the diaphragm 13 may also be a laminated structure consisting of a first resin and a second resin, as in the first resin substrate 110A described in embodiment 2. In this case, in the wound electrode body, the second resin may be wound around the winding axis Z along the first resin inside the first resin. Furthermore, the coefficient of linear expansion of the first resin may be greater than that of the second resin. For example, polyethylene may be used as the first resin, and polypropylene may be used as the second resin; however, it is not limited to these methods as long as the aforementioned relationship between the coefficients of linear expansion is satisfied.

[0108] The embodiments described above are illustrative and not restrictive in all respects. The scope of the invention is set forth in the claims and includes all modifications within the meaning and scope of the claims.

Claims

1. A wound electrode body, comprising a first electrode and a second electrode with a polarity different from the first electrode wound together in a flat shape with a diaphragm as a separator, comprising: The first resin component wound around the winding shaft; and A second resin component is wound around the winding shaft along the first resin component on the inner side of the first resin component. The coefficient of linear expansion of the first resin component is greater than that of the second resin component.

2. The wound electrode body according to claim 1, The first electrode comprises a first substrate and a first active material layer. The first substrate has the first resin component and a first conductive layer formed on the first resin component. The first active material layer is formed on the first conductive layer. The second electrode includes a second substrate and a second active material layer. The second substrate has the second resin component and a second conductive layer formed on the second resin component. The second active material layer is formed on the second conductive layer.

3. The wound electrode body according to claim 1, The first electrode includes a first substrate and a first active material layer. The first substrate has a resin substrate on which the first resin member and the second resin member are stacked and a first conductive layer formed on the resin substrate. The first active material layer is formed on the first conductive layer.

4. The wound electrode body according to claim 3, The resin substrate has an overlapping region that overlaps with the first active material layer and a non-overlapping region that does not overlap with the first active material layer in the lamination direction of the first resin component and the second resin component. The proportion of the second resin component in the overlapping region in the lamination direction is greater than the proportion of the second resin component in the non-overlapping region in the lamination direction.

5. The wound electrode body according to any one of claims 1 to 4, The first resin component comprises polyethylene, and the second resin component comprises polypropylene.

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