Energy storage cell

Abstract

To provide a power storage cell capable of suppressing a plurality of piece parts provided to an axial direction end part of a first electrode sheet from being contacted to a second electrode sheet.SOLUTION: A positive electrode sheet 10 (first electrode sheet) of a power storage cell 100, contains a long side 13 (first long side) positioned to an end part of a Z1 side (one side in a shaft direction). A negative electrode sheet 20 (second electrode sheet) contains a long side 23 (second side) positioned to the end part on the Z1 side. The positive electrode sheet 10 contains: a positive electrode collector 11 (first electrode collector); and a positive electrode mixture layer 12 (first electrode material layer). A positive electrode uncoating part 11b of the positive electrode collector 11 is formed to the long side 13, and contains a plurality of piece parts 13 (first piece part) arranged to an X direction (winding direction). An insulation part 25 (first insulation part and an insulation member) is formed to the long side 23 of the negative electrode sheet 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage cell. [Background technology]

[0002] U.S. Patent Application Publication No. 2016 / 0104875 (Patent Document 1) discloses a battery cell including an electrode assembly in which electrode sheets (positive and negative electrode sheets) are spirally wound. The electrode sheets are wound in a state in which the positive electrode sheet and the negative electrode sheet overlap with a separator interposed therebetween. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2016 / 0104875 Summary of the Invention [Problem to be solved by the invention]

[0004] Although not explicitly stated in Patent Document 1, there are cases where multiple pieces (metal pieces) are provided at the axial end of the electrode sheet. For example, multiple pieces of the positive electrode sheet (first electrode sheet) may be bent, causing the multiple pieces to come into contact with the negative electrode sheet (second electrode sheet).

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a storage cell that can prevent multiple pieces provided at the axial end of the first electrode sheet from contacting the second electrode sheet. [Means for solving the problem]

[0006] An energy storage cell according to one aspect of the present disclosure includes a wound electrode assembly including a first electrode sheet, a second electrode sheet, and a separator disposed between the first and second electrode sheets, and an insulating member. Each of the first and second electrode sheets is formed long in the winding direction of the wound electrode assembly. The first electrode sheet includes a first long side located at one end in the axial direction along which the winding axis of the wound electrode assembly extends. The second electrode sheet includes a second long side located at one end in the axial direction. The first electrode sheet includes a first electrode material layer and a first current collector including a first coated portion on which the first electrode material layer is formed and a first uncoated portion on which the first electrode material layer is not coated. The first uncoated portion is formed on the first long side and includes a plurality of first pieces arranged in the winding direction. The insulating member includes a first insulating portion formed on the second long side.

[0007] In the energy storage cell according to one aspect of the present disclosure, as described above, the first electrode sheet has a first long side located at one end in the axial direction, and the second electrode sheet has a first insulating portion located at the second long side located at one end in the axial direction, whereby even when the first long sides are bent toward the second electrode sheet, the first insulating portion can prevent the first long sides from contacting (becoming conductive with) the second electrode sheet.

[0008] In the energy storage cell according to the above aspect, preferably, the first electrode sheet includes a third long side located at the other end in the axial direction. The second electrode sheet includes a fourth long side located at the other end in the axial direction. The second electrode sheet includes a second electrode material layer, a second coated portion on which the second electrode material layer is formed, and a second current collector including a second uncoated portion not coated with the second electrode material layer. The second uncoated portion is formed on the fourth long side and includes a plurality of second arms arranged in the winding direction. The insulating member includes a second insulating portion formed on the third long side. With this configuration, even if the plurality of second arms are folded toward the first electrode sheet, the second insulating portion can prevent contact (conduction) between the plurality of second arms and the first electrode sheet.

[0009] In the energy storage cell according to the above aspect, the insulating member is preferably formed of a porous material. With this configuration, when an electrolyte solution is injected into the wound electrode body from one side in the axial direction, the electrolyte solution can be introduced into the inside of the wound electrode body through the insulating member, which is a porous material.

[0010] In this case, the insulating member is preferably formed continuously along the winding direction, which can more reliably prevent the electrode sheet from coming into contact with the piece portion.

[0011] In the energy storage cell according to the above aspect, the insulating members are preferably formed intermittently along the winding direction. With this configuration, gaps are formed between the insulating members, and therefore, when an electrolyte solution is injected into the wound electrode body from one side in the axial direction, it is possible to easily prevent the insulating members from blocking the entry of the electrolyte solution.

[0012] According to the present disclosure, it is possible to prevent the plurality of pieces provided at the axial end of the first electrode sheet from coming into contact with the second electrode sheet. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view showing a configuration of a storage cell according to an embodiment. [Figure 2] FIG. 1 is a schematic perspective view showing the configuration of a wound electrode body according to one embodiment. [Figure 3] FIG. 2 is a plan view showing the configuration of a positive electrode current collector plate according to one embodiment. [Figure 4] FIG. 2 is a plan view showing the configuration of a negative electrode current collector plate according to one embodiment. [Figure 5] FIG. 2 is a partially enlarged view of the vicinity of the positive electrode current collector plate in FIG. [Figure 6] FIG. 2 is a partially enlarged view of the vicinity of the negative electrode current collector plate in FIG. [Figure 7] 3A and 3B are diagrams illustrating the configuration of a positive electrode sheet and a negative electrode sheet according to one embodiment in an unwound state. [Figure 8]FIG. 10 is a diagram showing the configuration of a modified example of an embodiment in which a positive electrode sheet and a negative electrode sheet are unwound. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0015] The energy storage cell 100 includes a wound electrode body 1, a case 2, a positive electrode terminal 3, a positive electrode current collector plate 4, an external gasket 5, an internal gasket 6, a negative electrode current collector plate 7, a polymer ring 8, and a sealing plug 9.

[0016] The wound electrode body 1 is housed in a case 2. The case 2 has a cylindrical shape. The wound electrode body 1 is wound so as to have the same cylindrical shape as the case 2. In other words, the energy storage cell 100 is a cylindrical battery. The case 2 is made of copper, aluminum, or the like.

[0017] The case 2 includes a top plate 2a, a peripheral wall 2c, and a sealing plate 2d. The peripheral wall 2c is provided on the outer periphery of the wound electrode body 1 and has a cylindrical shape. The top plate 2a is connected to the Z1-side end of the peripheral wall 2c. The top plate 2a is formed integrally with the peripheral wall 2c. The sealing plate 2d is connected to the Z2-side end of the peripheral wall 2c. The sealing plate 2d covers the Z2-side opening of the peripheral wall 2c. A crimped portion 2e is formed at the Z2-side end of the peripheral wall 2c, and is crimped to the outer periphery of the sealing plate 2d. The crimped portion 2e is formed in an annular shape.

[0018] The wound electrode body 1 includes a positive electrode sheet 10, a negative electrode sheet 20, and a separator 30. The separator 30 is provided between the positive electrode sheet 10 and the negative electrode sheet 20. The separator 30 separates the positive electrode sheet 10 and the negative electrode sheet 20 while allowing ions (e.g., lithium ions) to move between the positive electrode sheet 10 (positive electrode active material) and the negative electrode sheet 20 (negative electrode active material). The wound electrode body 1 is composed of an electrode plate assembly in which the positive electrode sheet 10 and the negative electrode sheet 20 are wound with the separator 30 interposed therebetween. The positive electrode sheet 10 and the negative electrode sheet 20 are examples of the "first electrode sheet" and the "second electrode sheet," respectively, of the present disclosure.

[0019] As shown in Fig. 2, the wound electrode body 1 is formed by winding a positive electrode sheet 10, a negative electrode sheet 20, and a separator 30 around a winding axis α. In Fig. 2, the wound electrode body 1 is shown in a slightly unwound state so that the wound state of the wound electrode body 1 can be easily seen.

[0020] Referring again to FIG. 1, the positive electrode terminal 3 includes a disk portion 3a and a rivet portion 3b. The disk portion 3a is provided outside the case 2 and is therefore exposed. The rivet portion 3b is connected to the disk portion 3a. The rivet portion 3b is provided so as to extend from the center of the disk portion 3a toward the Z2 side. The positive electrode terminal 3 is made of aluminum.

[0021] The disk portion 3a is disposed on the top plate 2a of the case 2. The top plate 2a is provided at the end of the case 2 on the Z1 side. The top plate 2a is provided so as to be perpendicular to the Z direction. A through hole 2b (see FIG. 5) is provided in the top plate 2a. The rivet portion 3b extends from the disk portion 3a, which is disposed outside the case 2, through the through hole 2b to the inside of the case 2. The Z direction is an example of the "axial direction" in this disclosure.

[0022] The positive electrode current collector 4 is housed in the case 2. The positive electrode current collector 4 (a piece 4d described below) is welded to a positive electrode uncoated portion 11b (described below) of the positive electrode sheet 10. This causes the positive electrode current collector 4 to be positively charged. The positive electrode current collector 4 is welded to an end 3c on the Z2 side of the rivet portion 3b. This causes the positive electrode terminal 3 to be positively charged.

[0023] The external gasket 5 is provided on the outside of the case 2. Specifically, the external gasket 5 is disposed between the disk portion 3a of the positive terminal 3 and the top plate 2a of the case 2. This insulates the positive terminal 3 from the case 2.

[0024] The internal gasket 6 is provided inside the case 2. Specifically, the internal gasket 6 is disposed between the case 2 and the positive current collector plate 4. This insulates the case 2 from the positive current collector plate 4. The rivet portion 3b penetrates the internal gasket 6 and comes into contact with the positive current collector plate 4.

[0025] The negative electrode current collector 7 is housed in the case 2. The negative electrode current collector 7 (a piece 7d described below) is welded to a negative electrode uncoated portion 21b (described below) of the negative electrode sheet 20. This causes the negative electrode current collector 7 to be negatively charged. The negative electrode current collector 7 is in contact with the case 2. This causes the case 2 to be negatively charged.

[0026] The polymer ring 8 is provided between the outer peripheral edge of the sealing plate 2d and the crimped portion 2e formed on the peripheral wall portion 2c. The polymer ring 8 has an annular shape.

[0027] The sealing plug 9 plugs a through-hole 2f provided in the center of the sealing plate 2d. The sealing plug 9 passes through a through-hole 7g provided in the center of the negative electrode current collector plate 7 as well as the through-hole 2f.

[0028] 3 is a plan view of the positive current collector plate 4. The positive current collector plate 4 has a disk shape and includes a central portion 4a, spokes 4b, an outer peripheral edge portion 4c, and a piece portion 4d.

[0029] The central portion 4a is provided at the center of the positive current collector plate 4. The rivet portion 3b is joined to the central portion 4a. The spokes 4b are provided so as to extend radially outward from the central portion 4a. Six spokes 4b are provided at equal angular intervals around the central portion 4a of the positive current collector plate 4.

[0030] The outer peripheral edge portion 4c is provided on the outer peripheral edge of the positive current collector plate 4. Each of the six spokes 4b connects the outer peripheral edge portion 4c and the central portion 4a. The spokes 4b are formed to bend in the Z direction. Note that the central portion 4a of the positive current collector plate 4 moves (displaces) the most in the Z direction.

[0031] Between the circumferentially adjacent spokes 4b, a through hole 4e is formed. That is, six through holes 4e are formed. A piece 4d is provided inside each of the six through holes 4e. Each of the six pieces 4d is connected to the outer circumferential edge portion 4c by a connecting portion 4f. Each of the six pieces 4d has a shape that tapers radially inward.

[0032] 4 is a plan view of the negative electrode current collector 7. The negative electrode current collector 7 has a disk shape and includes a central portion 7a, spokes 7b, an outer peripheral edge portion 7c, and a piece portion 7d.

[0033] The central portion 7a is provided at the center of the negative electrode current collector 7. The spokes 7b are provided so as to extend radially outward from the central portion 7a. Six spokes 7b are provided at equal angular intervals around the central portion 7a of the negative electrode current collector 7.

[0034] The outer peripheral edge portion 7c is provided on the outer peripheral edge of the negative electrode current collector plate 7. Each of the six spokes 7b connects the outer peripheral edge portion 7c and the central portion 7a. Each spoke 7b is formed to bend in the Z direction. The outer peripheral edge portion 7c of the negative electrode current collector plate 7 moves (displaces) the most in the Z direction.

[0035] Between the circumferentially adjacent spokes 7b, a through hole 7e is formed. That is, six through holes 7e are formed. The pieces 7d are provided at positions corresponding to the six through holes 7e. Specifically, each of the six pieces 7d is disposed inside the corresponding through hole 7e. Each of the six pieces 7d is connected to the central portion 7a by a connecting portion 7f. Each of the six pieces 7d has a shape that tapers radially inward.

[0036] As shown in FIG. 5, the positive electrode sheet 10 includes a positive electrode current collector 11 and a positive electrode composite layer 12. The positive electrode composite layer 12 is applied to both radially opposite surfaces (R direction) of the positive electrode current collector 11 (a positive electrode coated portion 11a described below). The positive electrode composite layer 12 is in close contact with the separator 30. The positive electrode current collector 11 and the positive electrode composite layer 12 are examples of a "first current collector" and a "first electrode material layer," respectively.

[0037] Positive electrode current collector 11 is made of, for example, aluminum. Positive electrode mixture layer 12 is formed by applying a positive electrode slurry to the surface of positive electrode current collector 11 and drying it. The positive electrode slurry is prepared by kneading materials for positive electrode mixture layer 12 (such as a positive electrode active material and a binder) with a solvent. Positive electrode mixture layer 12 is in close contact with separator 30. The thickness of positive electrode mixture layer 12 is, for example, 0.1 μm or more and 1000 μm or less.

[0038] The positive electrode current collector 11 includes a positive electrode coated portion 11a and a positive electrode uncoated portion 11b. The positive electrode coated portion 11a is a portion of the positive electrode current collector 11 that is coated with the positive electrode composite layer 12. In other words, the positive electrode coated portion 11a is a portion that is not exposed because it is covered with the positive electrode composite layer 12. The positive electrode coated portion 11a and the positive electrode uncoated portion 11b are examples of a "first coated portion" and a "first uncoated portion" in the present disclosure, respectively.

[0039] The positive electrode uncoated portion 11b is an exposed portion of the positive electrode current collector 11 that is not covered by the positive electrode composite layer 12 or the insulating portion 15 described below. The positive electrode uncoated portion 11b is located on the Z1 side of the positive electrode coated portion 11a. Specifically, the positive electrode uncoated portion 11b protrudes from the positive electrode coated portion 11a toward the Z1 side. The Z1 side is an example of "one side in the axial direction" in the present disclosure.

[0040] The positive electrode uncoated portion 11b is bent radially inward by contacting the positive electrode current collector 4 arranged on the Z1 side. As a result, the positive electrode current collector 4 is positively charged. The positive electrode uncoated portion 11b is joined to the positive electrode current collector 4 by welding.

[0041] The positive electrode uncoated portion 11b includes a plurality of arm portions 11c. The plurality of arm portions 11c are arranged along the winding direction of the wound electrode body 1. The arm portions 11c are an example of the "first arm portion" of the present disclosure.

[0042] The negative electrode sheet 20 includes a negative electrode current collector 21 and a negative electrode composite layer 22. The negative electrode composite layer 22 is applied to both radially opposite surfaces (R direction) of the negative electrode current collector 21 (a negative electrode coated portion 21a described below). The negative electrode composite layer 22 is in close contact with the separator 30. The negative electrode current collector 21 and the negative electrode composite layer 22 are examples of the "second current collector" and the "second electrode material layer" of the present disclosure, respectively.

[0043] Negative electrode current collector 21 is made of, for example, copper. Negative electrode mixture layer 22 is formed by applying a negative electrode slurry to the surface of negative electrode current collector 21 and drying the coating. The negative electrode slurry is prepared by kneading materials for negative electrode mixture layer 22 (negative electrode active material, binder, etc.) with a solvent. The thickness of negative electrode mixture layer 22 is, for example, 0.1 μm or more and 1000 μm or less.

[0044] As shown in Fig. 6, the negative electrode current collector 21 includes a negative electrode coated portion 21a and a negative electrode uncoated portion 21b. The negative electrode coated portion 21a is a portion of the negative electrode current collector 21 that is coated with the negative electrode composite material layer 22. In other words, the negative electrode coated portion 21a is a portion that is not exposed because it is covered with the negative electrode composite material layer 22. The negative electrode coated portion 21a and the negative electrode uncoated portion 21b are examples of a "second coated portion" and a "second uncoated portion" of the present disclosure, respectively.

[0045] The negative electrode uncoated portion 21b is an exposed portion of the negative electrode current collector 21 that is not covered by the negative electrode composite layer 22 or the insulating portion 25 described below. The negative electrode uncoated portion 21b is located on the Z2 side of the negative electrode coated portion 21a. Specifically, the negative electrode uncoated portion 21b protrudes from the negative electrode coated portion 21a toward the Z2 side. The Z2 side is an example of the "other axial side" in the present disclosure.

[0046] The negative electrode uncoated portion 21b is bent radially inward by contacting the negative electrode current collector 7 arranged on the Z2 side. As a result, the negative electrode current collector 7 is negatively charged. The negative electrode uncoated portion 21b is joined to the negative electrode current collector 7 by welding.

[0047] The negative electrode uncoated portion 21b includes a plurality of arm portions 21c. The plurality of arm portions 21c are arranged along the winding direction of the wound electrode body 1. The arm portions 21c are an example of the "second arm portion" of the present disclosure.

[0048] 7, each of the positive electrode sheet 10 (positive electrode current collector 11) and the negative electrode sheet 20 (negative electrode current collector 21) is formed long in the winding direction of the wound electrode body 1. The winding direction of the wound electrode body 1 is the extension direction (X direction in FIG. 7) of the positive electrode sheet 10 (negative electrode sheet 20) in an unwound and spread out state.

[0049] The positive electrode sheet 10 includes a long side 13 and a long side 14. The long side 13 is located at the end of the positive electrode sheet 10 on the Z1 side. The long side 14 is located at the end of the positive electrode sheet 10 on the Z2 side. The positive electrode uncoated portion 11b (plurality of pieces 11c) is provided on the long side 13. The plurality of pieces 11c are arranged side by side along the X direction. The long side 13 and the long side 14 are examples of the "first long side" and "third long side" of the present disclosure, respectively.

[0050] The negative electrode sheet 20 includes a long side 23 and a long side 24. The long side 23 is located at the end of the negative electrode sheet 20 on the Z1 side. The long side 24 is located at the end of the negative electrode sheet 20 on the Z2 side. The negative electrode uncoated portion 21b (plurality of pieces 21c) is provided on the long side 24. The plurality of pieces 21c are arranged side by side along the X direction. The long side 23 and the long side 24 are examples of the "second long side" and the "fourth long side" of the present disclosure, respectively.

[0051] In the configuration of a conventional energy storage cell, for example, multiple pieces of the positive electrode sheet may be folded, causing the multiple pieces to come into contact with the negative electrode sheet.

[0052] Therefore, in this embodiment, the energy storage cell 100 includes an insulating portion 25 formed on the long side 23 of the negative electrode sheet 20. The insulating portion 25 is applied to a portion 25a (see FIG. 5 ) of the negative electrode current collector 21 that is not coated with the negative electrode composite layer 22. The portion 25a corresponds to the long side 23, and is a portion provided at the end of the negative electrode current collector 21 on the Z1 side. The insulating portion 25 is an example of a "first insulating portion" and an "insulating member" in the present disclosure.

[0053] The energy storage cell 100 also includes an insulating portion 15 formed on the long side 14 of the positive electrode sheet 10. The insulating portion 15 is applied to a portion 15a (see FIG. 6 ) of the positive electrode current collector 11 that is not coated with the positive electrode composite layer 12. The portion 15a corresponds to the long side 14, and is a portion provided at the end of the positive electrode current collector 11 on the Z2 side. The insulating portion 15 is an example of a "second insulating portion" and an "insulating member" of the present disclosure.

[0054] 5, the insulating portion 25 covers the portion 25a so that the portion 25a is not exposed. Specifically, the insulating portion 25 is formed to cover the portion 25a from both radial sides and the Z1 side. This ensures that the positive electrode uncoated portion 11b (side portion 11c) and the portion 25a are insulated from each other.

[0055] As described above, the insulating portion 25 is applied to the portion 25a of the negative electrode current collector 21 that is not coated with the negative electrode composite material layer 22. This prevents a step from occurring at the boundary between the portion 25a coated with the insulating portion 25 and the portion (21a) coated with the negative electrode composite material layer 22. As a result, it is possible to prevent stress from being applied to the negative electrode sheet 20 when the wound electrode body 1 expands and contracts.

[0056] 6, the insulating portion 15 covers the portion 15a so that the portion 15a is not exposed. Specifically, the insulating portion 15 is formed to cover the portion 15a from both radial sides and the Z2 side. This insulates the negative electrode uncoated portion 21b (side portion 21c) from the portion 15a.

[0057] As described above, the insulating portion 15 is applied to the portion 15a of the positive electrode current collector 11 that is not coated with the positive electrode composite layer 12. This prevents a step from occurring at the boundary between the portion 15a coated with the insulating portion 15 and the portion (11a) coated with the positive electrode composite layer 12. As a result, it is possible to prevent stress from being applied to the positive electrode sheet 10 when the wound electrode body 1 expands and contracts.

[0058] 7, the insulating portion 15 is formed continuously in the X direction. That is, the insulating portion 15 is made of a single member extending in the X direction. Similarly, the insulating portion 25 is formed continuously in the X direction. That is, the insulating portion 25 is made of a single member extending in the X direction.

[0059] Specifically, the insulating portion 15 is formed to extend from the X1 side end 11d (for example, the winding start portion) of the positive electrode sheet 10 to the X2 side end 11e (winding end portion) of the positive electrode sheet 10. The insulating portion 25 is formed to extend from the X1 side end 21d (winding start portion) of the negative electrode sheet 20 to the X2 side end 21e (winding end portion) of the negative electrode sheet 20.

[0060] In this embodiment, each of insulating portion 15 and insulating portion 25 is made of a porous material. Specifically, each of insulating portion 15 and insulating portion 25 is made of alumina. In Fig. 7, pores contained in the alumina are indicated by dots 16 to indicate that each of insulating portion 15 and insulating portion 25 is made of a porous material.

[0061] This allows gas and liquid to pass through each of insulating parts 15 and 25. As a result, it is possible to prevent insulating parts 15 and 25 from interfering with the injection of the electrolyte.

[0062] Furthermore, since alumina is heat resistant, the insulating portions 15 and 25 can prevent heat from being applied to the separator, etc. Therefore, when welding the piece 11c and the positive current collector plate 4 and when welding the piece 21c and the negative current collector plate 7, the application of heat to the separator, etc. can be prevented.

[0063] As described above, in this embodiment, the insulating portion 25 is formed on the long side 23 of the negative electrode sheet 20. This allows the insulating portion 25 to electrically isolate the positive electrode uncoated portion 11b (side portion 11c) of the positive electrode sheet 10 from the long side 23 of the negative electrode sheet 20. As a result, electrical conduction between the positive electrode sheet 10 and the negative electrode sheet 20 can be prevented.

[0064] FIG. 8 is a diagram showing a modified example of the above embodiment. As shown in FIG. 8, the positive electrode sheet 110 includes a positive electrode current collector 111, a long side 113, and a long side 114. The long side 113 is located at the end of the positive electrode sheet 110 on the Z1 side. The long side 114 is located at the end of the positive electrode sheet 110 on the Z2 side. A plurality of pieces 11c are provided on the long side 113. An insulating portion 115 (the shaded portion in FIG. 8) is formed on the long side 114. The positive electrode sheet 110 and the positive electrode current collector 111 are examples of the "first electrode sheet" and the "first current collector" of the present disclosure, respectively. The long side 113 and the long side 114 are examples of the "first long side" and the "second long side" of the present disclosure, respectively. The insulating portion 115 is an example of the "second insulating portion" and the "insulating member" of the present disclosure.

[0065] The insulating portions 115 are formed intermittently along the X direction. The distance D1 between the insulating portions 115 increases toward the X2 side (winding end side). The width W1 of the insulating portions 115 in the X direction increases toward the X2 side (winding end side). As a result, when the positive electrode sheet 110 is wound, layers on which the insulating portions 115 are formed and layers on which the insulating portions 115 are not formed are arranged alternately. Note that the width W1 and the distance D1 may be constant regardless of the position in the X direction.

[0066] The negative electrode sheet 120 includes a negative electrode current collector 121, a long side 123, and a long side 124. The long side 123 is located at the end of the negative electrode sheet 120 on the Z1 side. The long side 124 is located at the end of the negative electrode sheet 120 on the Z2 side. A plurality of pieces 21c are provided on the long side 124. An insulating portion 125 (the shaded portion in FIG. 8 ) is formed on the long side 123. The negative electrode sheet 120 and the negative electrode current collector 121 are examples of a "second electrode sheet" and a "second current collector," respectively, in the present disclosure. The long side 123 and the long side 124 are examples of a "first long side" and a "second long side," respectively, in the present disclosure. The insulating portion 125 is an example of a "first insulating portion" and an "insulating member" in the present disclosure.

[0067] The insulating portions 125 are formed intermittently along the X direction. The distance D2 between the insulating portions 125 increases toward the X2 side (winding end side). The width W2 of the insulating portions 125 in the X direction increases toward the X2 side (winding end side). As a result, when the positive electrode sheet 110 is wound, layers on which the insulating portions 125 are formed and layers on which the insulating portions 125 are not formed are alternately arranged. Note that the width W2 and the distance D2 may be constant regardless of the position in the X direction.

[0068] Furthermore, each of insulating portion 115 and insulating portion 125 does not have to be made of a porous material as in the above embodiment. For example, insulating portion 115 may be made of polypropylene. Also, insulating portion 125 may be made of polyethylene. Each of insulating portion 115 and insulating portion 125 may be made of a porous material. Also, one of the positive electrode side insulating portion and the negative electrode side insulating portion may be formed continuously in the X direction, and the other of the positive electrode side insulating portion and the negative electrode side insulating portion may be formed intermittently in the X direction.

[0069] In the above embodiment, an example was shown in which an insulating portion was formed on each of the positive electrode sheet 10 and the negative electrode sheet 20, but the present disclosure is not limited to this. An insulating portion may be formed on only one of the positive electrode sheet 10 and the negative electrode sheet 20.

[0070] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0071] 10, 110 positive electrode sheet (first electrode sheet), 11, 111 positive electrode current collector (first current collector), 11a positive electrode coated portion (first coated portion), 11b positive electrode uncoated portion (first uncoated portion), 11c side portion (first side portion), 12 positive electrode composite layer (first electrode material layer), 13, 113 long side (first long side), 14, 114 long side (third long side), 15, 115 insulating portion (second insulating portion) (insulating member), 20, 120 negative electrode sheet (second electrode sheet), 21 negative electrode current collector (second current collector), 21a negative electrode coated portion (second coated portion), 21b negative electrode uncoated portion (second uncoated portion), 21c side portion (second side portion), 22 negative electrode composite layer (second electrode material layer), 23, 123 Long side (second long side), 24, 124 Long side (fourth long side), 25, 125 Insulating portion (first insulating portion) (insulating member), 30 Separator, 100 Storage cell, X direction (winding direction), α Winding axis.

Claims

1. a wound electrode body including a first electrode sheet, a second electrode sheet, and a separator disposed between the first electrode sheet and the second electrode sheet; An insulating member; An external terminal, a current collector plate electrically connected to the external terminal, each of the first electrode sheet and the second electrode sheet is formed long in the winding direction of the wound electrode body, the first electrode sheet includes a first long side located at one end in an axial direction in which a winding axis of the wound electrode body extends, the second electrode sheet includes a second long side located at the end on the one side in the axial direction, The first electrode sheet is a first electrode material layer; a first current collector including a first coated portion on which the first electrode material layer is formed, and a first uncoated portion on which the first electrode material layer is not coated, the first uncoated portion is formed on the first long side and includes a plurality of first pieces arranged in the winding direction, the plurality of first pieces are welded to the current collecting plate, The insulating member is It is not formed on the first long side, The energy storage cell includes a first insulating portion formed on the second long side.

2. the first electrode sheet includes a third long side located at the other end in the axial direction, the second electrode sheet includes a fourth long side located at the end on the other side in the axial direction, The second electrode sheet is a second electrode material layer; a second current collector including a second coated portion on which the second electrode material layer is formed, and a second uncoated portion on which the second electrode material layer is not coated, the second uncoated portion is formed on the fourth long side and includes a plurality of second pieces arranged in the winding direction, The energy storage cell according to claim 1 , wherein the insulating member includes a second insulating portion formed on the third long side.

3. The energy storage cell according to claim 1 or 2, wherein the insulating member is made of a porous material.

4. A storage cell as described in Claim 3, wherein the insulating member is formed from alumina.

5. The energy storage cell according to claim 3 , wherein the insulating member is formed continuously along the winding direction.

6. The insulating member is formed intermittently along the winding direction, the spacing between the insulating members in the winding direction increases toward the winding end side, In addition to the spacing, the width of the insulating member in the winding direction also increases toward the winding end side, 3. The energy storage cell according to claim 1, wherein, in a wound state, layers on which the insulating member is formed and layers on which the insulating member is not formed are alternately arranged along a radial direction of the wound electrode body.

7. Either the first insulating portion or the second insulating portion is formed continuously along the winding direction, The energy storage cell according to claim 2 , wherein the other of the first insulating portion and the second insulating portion is formed intermittently along the winding direction.

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