Power storage cell

Abstract

To provide a power storage cell that can reduce stress on a tab lead.SOLUTION: A power storage cell 1 includes a wound electrode body 100 and a cell case 200 that accommodates the wound electrode body 100. The wound electrode body 100 includes an electrode plate 110 and a tab lead 140. The electrode plate 110 includes a current collector foil 111 and an electrode material layer 112. The electrode material layer 112 is applied on a part of the current collector foil 111. The tab lead 140 includes a curved portion 141 and an extending portion 142. The curved portion 141 is provided on an uncoated portion 111a of the current collector foil 111 where the electrode material layer 112 is not applied, and extends to be curved along a winding direction X of the wound electrode body 100. The extending portion 142 extends from the curved portion 141 and protrudes to one side of the current collector foil 111 in an axial direction Z of the wound electrode body 100. The curved portion 141 includes a groove portion 141S extending along the axial direction Z.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a storage cell.

Background Art

[0002] Patent Document 1 (Japanese Patent No. 3203517) discloses a conventional storage cell, which includes a wound electrode body, a first electrode lead, and a battery can housing the wound electrode body. The first electrode lead is provided by joining with a first strip-shaped electrode at the wound end portion on the outer peripheral side of the wound electrode body. The second electrode lead is provided by joining with a second strip-shaped electrode at the wound end portion on the inner peripheral side of the wound electrode body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, an increase in the size of storage cells has been desired. When the size of the storage cell is increased, the current flowing through the wound electrode body becomes larger. Therefore, in the winding direction of the wound electrode body, it is conceivable to increase the length of the tab lead (electrode lead). As a result, it is expected that the electrical resistance of the tab lead will be reduced. However, by increasing the tab lead, the stress applied to the portion of the tab lead that curves along the winding direction of the wound electrode body also increases.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a storage cell capable of reducing the stress of the tab lead.

Means for Solving the Problems

[0006] A power storage cell according to one aspect of the present disclosure includes a wound electrode body and a cell case that houses the wound electrode body. The wound electrode body includes an electrode plate and a tab lead. The electrode plate has a current collector foil and an electrode material layer. The electrode material layer is coated on a part of the current collector foil. The tab lead includes a curved portion and an extending portion. The curved portion is provided on an uncoated portion of the current collector foil where the electrode material layer is not coated, and extends along the winding direction of the wound electrode body so as to be curved. The extending portion extends from the curved portion and exits to one side of the current collector foil in the axial direction of the wound electrode body. The curved portion has a groove portion extending along the axial direction.

[0007] According to the above configuration, the curved portion can be easily bent at the groove portion. Therefore, even if the tab lead is enlarged in the winding direction, the curved portion can extend in a direction closer to the winding direction. As a result, the stress of the tab lead can be reduced.

[0008] In a power storage cell according to one aspect of the present disclosure, preferably, the curved portion has a plurality of groove portions arranged in the winding direction.

[0009] According to the above configuration, the curved portion can extend in a direction even closer to the winding direction. As a result, the stress of the tab lead can be further reduced.

[0010] In a power storage cell according to one aspect of the present disclosure, preferably, the extending portion has a root portion. The root portion is a portion connected to the curved portion. The root portion is arranged so as not to be aligned with the groove portion in the axial direction.

[0011] According to the above configuration, it is possible to suppress the extending portion from being bent unintentionally as the curved portion is bent at the groove portion.

[0012] In a power storage cell according to one aspect of the present disclosure, preferably, the tab lead has a plurality of extending portions arranged in the winding direction. Each of the plurality of extending portions has a root portion that is a portion connected to the curved portion. The root portion of each of the plurality of extending portions is arranged so as not to be aligned with the groove portion in the axial direction.

[0013] According to the above configuration, since a plurality of extending portions are provided, the heat generating portions of the tab lead can be dispersed. And since the plurality of extending portions are arranged as described above, it is possible to suppress the plurality of extending portions from bending in an unintended manner.

[0014] In the storage battery cell according to one aspect of the present disclosure, preferably, the tab lead has a plurality of extending portions arranged in the winding direction. Each of the plurality of extending portions has a root portion that is a portion connected to the curved portion. The root portions of each of the plurality of extending portions are arranged so as not to be aligned with any of the plurality of groove portions in the axial direction. The root portions of each of the plurality of extending portions are separated from each other in the winding direction.

[0015] According to the above configuration, since a plurality of extending portions are provided, the heat generating portions of the tab lead can be dispersed. Since the plurality of extending portions are arranged as described above, it is possible to suppress the plurality of extending portions from bending in an unintended manner. Furthermore, since the root portions are separated from each other, the plurality of extending portions are likely to bend toward the radial center at the root portions. Therefore, the extending directions of the plurality of extending portions can be easily adjusted.

Advantages of the Invention

[0016] According to the present disclosure, the stress of the tab lead can be reduced.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying out the Invention

[0018] 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 denoted by the same reference numerals, and the description thereof will not be repeated.

[0019] The power storage cell according to an embodiment of the present disclosure described below is, for example, a lithium-ion battery mounted on a vehicle. Note that the application and type of the power storage cell are not limited to the above example.

[0020] FIG. 1 is a cross-sectional view showing a power storage cell according to an embodiment of the present disclosure. FIG. 1 shows the overall configuration of a power storage cell 1 according to an embodiment of the present disclosure.

[0021] As shown in FIG. 1, the power storage cell 1 includes a wound electrode body 100 and a cell case 200.

[0022] The wound electrode body 100 includes a positive electrode plate 110, a negative electrode plate 120, a separator 130, a positive electrode tab lead 140, and a negative electrode tab lead 150. The wound electrode body 100 is configured to include a plate group in which the positive electrode plate 110 and the negative electrode plate 120 are wound via the separator 130.

[0023] FIG. 2 is a schematic plan view of a part of the wound electrode body as viewed from one side in the axial direction of the wound electrode body. FIG. 3 is a schematic diagram showing a positive electrode plate and a positive electrode tab lead in a state where the winding is released and extended in a planar shape.

[0024] As shown in FIGS. 2 and 3, the positive electrode plate 110 has a positive electrode current collector foil 111 and a positive electrode material layer 112. The positive electrode material layer 112 is coated on a part of the positive electrode current collector foil 111.

[0025] The positive electrode current collector foil 111 has an uncoated portion 111a and a coated portion 111b. The uncoated portion 111a is the portion of the positive electrode current collector foil 111 where the positive electrode material layer 112 is not coated. The coated portion 111b is the portion of the positive electrode current collector foil 111 where the positive electrode material layer 112 is coated.

[0026] In the present embodiment, the uncoated portion 111a is provided at each end of the positive electrode plate 110 on the X1 side and the X2 side. The X1 side is the winding end side in the winding direction X of the wound electrode body 100. The X2 side is the winding start side in the winding direction X. That is, the X1 side is the outer peripheral side in the radial direction R of the wound electrode body 100, and the X2 side is the center side in the radial direction R of the wound electrode body 100.

[0027] In the positive electrode plate 110 of the present embodiment, one coated portion 111b is provided so as to be continuous in the winding direction X. That is, in the positive electrode plate 110, one positive electrode material layer 112 is provided so as to be continuous in the winding direction X. However, a plurality of coated portions 111b may be provided at intervals in the winding direction X. That is, a plurality of positive electrode material layers 112 may be provided at intervals in the winding direction X. The uncoated portion 111a may be disposed between a plurality of coated portions 111b in the winding direction X.

[0028] For example, aluminum is used for the positive electrode current collector foil 111. The positive electrode material layer 112 is formed by coating the positive electrode slurry on the surface of the positive electrode current collector foil 111 and drying it. The positive electrode slurry is a slurry adjusted by kneading a positive electrode active material, a binder, etc. with a solvent. The positive electrode material layer 112 is in close contact with the separator 130. The thickness of the positive electrode material layer 112 is, for example, 0.1 μm or more and 1000 μm or less.

[0029] Note that the positive electrode plate 110, the positive electrode current collector foil 111, and the positive electrode material layer 112 may each be an example of the "electrode plate", the "current collector foil", and the "electrode material layer" of the present disclosure.

[0030] FIG. 4 is a schematic plan view of a part of the wound electrode body as viewed from the other side in the axial direction of the wound electrode body. FIG. 5 is a schematic diagram showing the negative electrode plate and the negative electrode tab lead in a state where the winding is unwound and extends in a planar shape.

[0031] As shown in FIGS. 4 and 5, the negative electrode plate 120 has a negative electrode current collector foil 121 and a negative electrode material layer 122. The negative electrode material layer 122 is coated on a part of the negative electrode current collector foil 121.

[0032] The negative electrode current collector foil 121 has an uncoated part 121a and a coated part 121b. The uncoated part 121a is the part of the negative electrode current collector foil 121 where the negative electrode material layer 122 is not coated. The coated part 121b is the part of the negative electrode current collector foil 121 where the negative electrode material layer 122 is coated.

[0033] In the present embodiment, the uncoated part 121a is provided at each end of the negative electrode plate 120 on the X1 side and the X2 side.

[0034] In the negative electrode plate 120 of the present embodiment, one coated part 121b is provided so as to be continuous in the winding direction X. That is, in the negative electrode plate 120, one negative electrode material layer 122 is provided so as to be continuous in the winding direction X. However, a plurality of coated parts 121b may be provided at intervals in the winding direction X. That is, a plurality of negative electrode material layers 122 may be provided at intervals in the winding direction X. The uncoated part 121a may be disposed between the plurality of coated parts 121b in the winding direction X.

[0035] For example, copper is used for the negative electrode current collector foil 121. The negative electrode material layer 122 is formed by coating the negative electrode slurry on the surface of the negative electrode current collector foil 121 and drying it. The negative electrode slurry is a slurry adjusted by kneading a negative electrode active material, a binder, etc. with a solvent. The negative electrode material layer 122 is in close contact with the separator 130. The thickness of the negative electrode material layer 122 is, for example, 0.1 μm or more and 1000 μm or less.

[0036] Note that the negative electrode plate 120, the negative electrode current collector foil 121, and the negative electrode material layer 122 can each be another example of the "electrode plate", "current collector foil", and "electrode material layer" of the present disclosure.

[0037] As shown in FIGS. 1, 2, and 4, the separator 130 is provided between the positive electrode plate 110 and the negative electrode plate 120. The separator 130 separates the positive electrode plate 110 and the negative electrode plate 120 while allowing ions (e.g., lithium ions) to move back and forth between the positive electrode material layer 112 of the positive electrode plate 110 and the negative electrode material layer 122 of the negative electrode plate 120.

[0038] As shown in FIGS. 1 to 3, the positive electrode tab lead 140 is provided so as to protrude from the positive electrode current collector foil 111 of the positive electrode plate 110 to one side (Z1 side) in the axial direction Z. The positive electrode tab lead 140 includes a curved portion 141 and an extending portion 142.

[0039] The curved portion 141 is provided on the uncoated portion 111a. The curved portion 141 is provided on the uncoated portion 111a located at the end portion on the X1 side of the positive electrode plate 110. However, the curved portion 141 may be provided on the uncoated portion 111a located at the end portion on the X2 side of the positive electrode plate 110. When the uncoated portion 111a is not located at the end portion of the positive electrode plate 110 in the winding direction X, the curved portion 141 may be provided on such an uncoated portion 111a. The curved portion 141 extends so as to curve along the winding direction X of the wound electrode body 100.

[0040] In the present embodiment, the curved portion 141 protrudes to one side (Z1 side) of the positive electrode current collector foil 111 in the axial direction Z of the wound electrode body 100. Thereby, the extending portion 142 is likely to bend at the root portion 142a of the extending portion 142. Note that the entire curved portion 141 may be provided on the uncoated portion 111a.

[0041] The bent portion 141 has a groove portion 141S. The groove portion 141S extends along the axial direction Z. The bent portion 141 has a plurality of groove portions 141S. The plurality of groove portions 141S are arranged in the winding direction X. The plurality of groove portions 141S are arranged at substantially equal intervals in the winding direction X. Each groove portion 141S extends from one end edge to the other end edge of the bent portion 141 in the axial direction Z. Each groove portion 141S extends linearly along the axial direction Z.

[0042] The extending portion 142 extends from the bent portion 141. The bent portion 141 protrudes to one side (Z1 side) of the positive current collector foil 111 in the axial direction Z of the wound electrode body 100.

[0043] The extending portion 142 has a root portion 142a. The root portion 142a is a portion connected to the bent portion 141. The root portion 142a is arranged so as not to be aligned with the groove portion 141S in the axial direction Z.

[0044] The extending portion 142 is bent at the root portion 142a. The extending portion 142 is bent toward the center side in the radial direction R of the wound electrode body 100.

[0045] The positive tab lead 140 has a plurality of extending portions 142. The plurality of extending portions 142 are arranged in the winding direction X. Each of the plurality of extending portions 142 has a root portion 142a which is a portion connected to the bent portion 141. The root portions 142a of each of the plurality of extending portions 142 are arranged so as not to be aligned with the groove portion 141S in the axial direction Z. Specifically, each root portion 142a is arranged so as not to be aligned with any of the plurality of groove portions 141S in the axial direction Z. The root portions 142a of each of the plurality of extending portions 142 are spaced apart from each other in the winding direction X.

[0046] The plurality of extending portions 142 are bent at their respective root portions 142a. The plurality of extending portions 142 are bent toward the center side in the radial direction R of the wound electrode body 100. When viewed from the axial direction Z, the plurality of extending portions 142 overlap each other. The plurality of extending portions 142 may be welded to each other.

[0047] As shown in FIGS. 1, 4, and 5, the negative tab lead 150 is provided so as to protrude from the negative current collector foil 121 of the negative electrode plate 120 to the other side (Z2 side) in the axial direction Z. The negative tab lead 150 includes a curved portion 151 and an extending portion 152.

[0048] The curved portion 151 is provided on the uncoated portion 111a. The curved portion 151 is provided on the uncoated portion 121a located at the end on the X2 side of the negative electrode plate 120. However, the curved portion 151 may be provided on the uncoated portion 121a located at the end on the X1 side of the negative electrode plate 120. When the uncoated portion 121a is not located at the end of the negative electrode plate 120 in the winding direction X, the curved portion 151 may be provided on such an uncoated portion 121a. The curved portion 151 extends so as to curve along the winding direction X.

[0049] In the present embodiment, the curved portion 151 protrudes to the other side (Z2 side) of the negative current collector foil 121 in the axial direction Z of the wound electrode body 100. Thereby, the extending portion 152 is likely to bend at the root portion 152a of the extending portion 152. Note that the entire curved portion 151 may be provided on the uncoated portion 111a.

[0050] The curved portion 151 has a groove portion 151S. The groove portion 151S extends along the axial direction Z. The curved portion 151 has a plurality of groove portions 151S. The plurality of groove portions 151S are arranged in the winding direction X. The plurality of groove portions 151S are arranged at substantially equal intervals in the winding direction X. Each groove portion 151S extends from one end edge of the curved portion 151 in the axial direction Z to the other end edge. Each groove portion 151S extends linearly along the axial direction Z.

[0051] The extending portion 152 extends from the curved portion 151. The extending portion 152 protrudes to the other side (Z2 side) of the negative current collector foil 121 in the axial direction Z of the wound electrode body 100.

[0052] The extending portion 152 has a root portion 152a. The root portion 152a is a portion that is connected to the curved portion 151. The root portion 152a is arranged so as not to be aligned with the groove portion 151S in the axial direction Z.

[0053] The extending portion 152 is bent at the root portion 152a. The extending portion 152 is bent toward the center side in the radial direction R of the wound electrode body 100.

[0054] The negative electrode tab lead 150 has a plurality of extending portions 152. The plurality of extending portions 152 are arranged side by side in the winding direction X. Each of the plurality of extending portions 152 has a root portion 152a which is a portion connected to the curved portion 151. The root portion 152a of each of the plurality of extending portions 152 is arranged so as not to be aligned with the groove portion 151S in the axial direction Z. Specifically, each root portion 152a is arranged so as not to be aligned with any of the plurality of groove portions 151S in the axial direction Z. The root portion 152a of each of the plurality of extending portions 152 is separated from each other in the winding direction X.

[0055] The plurality of extending portions 152 are bent at their respective root portions 152a. The plurality of extending portions 152 are bent toward the center side in the radial direction R of the wound electrode body 100. When viewed from the axial direction Z, the plurality of extending portions 152 overlap each other. The plurality of extending portions 152 may be welded to each other.

[0056] As shown in FIG. 1, the cell case 200 houses the wound electrode body 100. The cell case 200 has a cylindrical outer shape. Therefore, the storage battery 1 is a cylindrical battery.

[0057] The cell case 200 has an outer peripheral wall portion 210, a first end portion 220, and a second end portion 230.

[0058] The outer peripheral wall portion 210 is cylindrical and is disposed outside in the radial direction R of the wound electrode body 100. The outer peripheral wall portion 210 is formed of copper, aluminum, or the like. The outer peripheral wall portion 210 is in contact with the negative electrode current collector of the negative electrode plate 120 provided on the outermost periphery of the wound electrode body 100.

[0059] The first end portion 220 is connected to one side (Z1 side) of the outer peripheral wall portion 210 in the axial direction Z of the wound electrode body 100. The first end portion 220 is connected to one side (Z1 side) of the outer peripheral wall portion 210 in the axial direction Z of the wound electrode body 100.

[0060] Specifically, the first end portion 220 has an external cap 222, an insulating layer 223, and a caulking portion 224.

[0061] The external cap 222 has a function as an external terminal by being electrically connected to an external bus bar (not shown). The external cap 222 is provided with a fragile portion 225 (thin portion). The external cap 222 is likely to break starting from the fragile portion 225 when the internal pressure of the cell case 200 rises. Thereby, gas is quickly discharged outside the cell case 200. The external cap 222 is formed of copper, aluminum, or the like.

[0062] The insulating layer 223 is disposed so as to cover the outer peripheral end of the external cap 222. The insulating layer 223 is provided to insulate the external cap 222 and the caulking portion 224.

[0063] The caulking portion 224 is connected to one side of the outer peripheral wall portion 210 in the axial direction Z of the wound electrode body 100. The caulking portion 224 is integrally formed with the outer peripheral wall portion 210. The caulking portion 224 caulks the outer peripheral edge of the external cap 222 (and the conductive film 510 described later) via the insulating layer 223. The caulking portion 224 is formed of copper, aluminum, or the like.

[0064] The second end portion 230 is connected to the other side (Z2 side) of the outer peripheral wall portion 210 in the axial direction Z. The second end portion 230 has a disc-shaped outer shape. The second end portion 230 is formed of copper, aluminum, or the like. The periphery of the second end portion 230 is connected to the outer peripheral wall portion 210. The second end portion 230 is integrally formed with the outer peripheral wall portion 210.

[0065] The second end portion 230 is in contact with the negative electrode tab lead 150. Thereby, the negative electrode tab lead 150 and the second end portion 230 are electrically connected. As a result, the second end portion 230, the outer peripheral wall portion 210 connected to the second end portion 230, and the caulking portion 224 are negatively charged.

[0066] The storage battery cell 1 further includes a positive-side insulating plate 300, a negative-side insulating plate 400, and a CID (Current Interrupt Device) 500.

[0067] The positive-side insulating plate 300 is housed in the cell case 200. The positive-side insulating plate 300 is provided so as to insulate the wound electrode body 100 (negative electrode plate 120 and separator 130) from the cell case 200. The positive-side insulating plate 300 is provided so as to cover the positive electrode plate 110, the negative electrode plate 120, and the separator 130 from one side (Z1 side).

[0068] The positive-side insulating plate 300 has a first through hole 310. The extending portion 142 of the positive electrode tab lead 140 is inserted into the first through hole 310 and thereby contacts a conductive film 510 described later. Thereby, the positive electrode tab lead 140 and the conductive film 510 are electrically connected.

[0069] The negative-side insulating plate 400 is housed in the cell case 200. The negative-side insulating plate 400 is provided so as to insulate the wound electrode body 100 (positive electrode plate 110 and separator 130) from the cell case 200. The negative-side insulating plate 400 is provided so as to cover the positive electrode plate 110, the negative electrode plate 120, and the separator 130 from the other side (Z2 side).

[0070] The negative-side insulating plate 400 has a second through-hole 410. The extending portion 152 of the negative electrode tab lead 150 is inserted through the second through-hole 410. Thereby, the extending portion 152 of the negative electrode tab lead 150 and the second end portion 230 are electrically connected.

[0071] The CID 500 is an element that cuts off the current path by utilizing the increase in the internal pressure of the cell due to the gas generated by overcharging of the storage cell 1. The CID 500 is provided so as to seal the opening on one side (Z1 side) of the outer peripheral wall portion 210. The CID 500 has a conductive film 510, a gasket 520, and a bottom disk 530.

[0072] The conductive film 510 is provided so as to seal the opening on one side (Z1 side) of the outer peripheral wall portion 210. The conductive film 510 is in contact with the extending portion 142 of the positive electrode tab lead 140. Thereby, the conductive film 510 is positively charged. Also, the conductive film 510 is electrically connected to the external cap 222 by a connecting member (not shown). Thereby, the external cap 222 is also positively charged.

[0073] Specifically, the conductive film 510 includes a protruding portion 511 that protrudes toward the wound electrode body 100 side (Z2 side). The protruding portion 511 is in contact with the extending portion 142 of the positive electrode tab lead 140.

[0074] The conductive film 510 is provided with a fragile portion 512 (thin portion) similar to the external cap 222. The conductive film 510 is likely to break starting from the fragile portion 512 when the internal pressure of the cell case 200 increases. When the conductive film 510 breaks due to the increase in the internal pressure, the contact between the conductive film 510 and the extending portion 142 of the positive electrode tab lead 140 is released. As a result, the positive charge of the conductive film 510 is eliminated, and the positive charge of the external cap 222 is eliminated. As a result, the charge and discharge of the storage cell 1 are stopped.

[0075] The gasket 520 is located on the side of the wound electrode body 100 of the conductive film 510. The bottom disk 530 is connected to the conductive film 510 via the gasket 520. The protruding portion 511 of the conductive film 510 penetrates through the gasket 520 and the bottom disk 530.

[0076] As described above, in the storage battery cell 1 according to the embodiment of the present disclosure, in the positive electrode tab lead 140, the curved portion 141 has the groove portion 141S. Thereby, the curved portion 141 is easily bent at the groove portion 141S. Therefore, even if the positive electrode tab lead 140 is enlarged in the winding direction X, the curved portion 141 can extend in a direction closer to the winding direction X. As a result, the stress of the positive electrode tab lead 140 can be reduced.

[0077] Furthermore, also in the negative electrode tab lead 150, the curved portion 151 has the groove portion 151S. Thereby, the curved portion 151 is easily bent at the groove portion 151S. Therefore, even if the negative electrode tab lead 150 is enlarged in the winding direction X, the curved portion 151 can extend in a direction closer to the winding direction X. As a result, the stress of the negative electrode tab lead 150 can be reduced.

[0078] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present disclosure is shown not by the description of the above-described embodiments but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Explanation of Reference Numerals

[0079] 1 Storage cell, 100 wound electrode body, 110 positive electrode plate, 111 positive current collector foil, 111a uncoated portion, 111b coated portion, 112 positive electrode material layer, 120 negative electrode plate, 121 negative current collector foil, 121a uncoated portion, 121b coated portion, 122 negative electrode material layer, 130 separator, 140 positive tab lead, 141 curved portion, 141S groove portion, 142 extending portion, 142a base portion, 150 negative tab lead, 151 curved portion, 151S groove portion, 152 extending portion, 152a base portion, 200 cell case, 210 outer peripheral wall portion, 220 first end portion, 222 external cap, 223 insulating layer, 224 caulked portion, 225 fragile portion, 230 second end portion, 300 positive side insulating plate, 310 first through hole, 400 negative side insulating plate, 410 second through hole, 500 CID, 510 conductive film, 511 protruding portion, 512 fragile portion, 520 gasket, 530 bottom disk.

Claims

1. A wound electrode body, and a cell case for housing the wound electrode body, wherein the wound electrode body includes an electrode plate and a tab lead, the electrode plate has a current collector foil and an electrode material layer coated on a part of the current collector foil, the tab lead is, provided on an uncoated portion of the current collector foil where the electrode material layer is not coated, and extends so as to curve along the winding direction of the wound electrode body; a curved portion, and an extending portion extending from the curved portion and protruding to one side of the current collector foil in the axial direction of the wound electrode body, the curved portion has a groove portion extending along the axial direction, a power storage cell.

2. The power storage cell according to claim 1, wherein the curved portion has a plurality of groove portions arranged in the winding direction.

3. The extending portion has a root portion which is a portion connecting to the curved portion, the root portion is arranged so as not to be aligned with the groove portion in the axial direction, the power storage cell according to claim 1.

4. the tab lead has a plurality of extending portions arranged in the winding direction, each of the plurality of extending portions has a root portion which is a portion connecting to the curved portion, the root portion of each of the plurality of extending portions is arranged so as not to be aligned with the groove portion in the axial direction, the power storage cell according to claim 1.

5. the tab lead has a plurality of extending portions arranged in the winding direction, each of the plurality of extending portions has a root portion which is a portion connecting to the curved portion, the root portion of each of the plurality of extending portions is arranged so as not to be aligned with any of the plurality of groove portions in the axial direction, The respective root portions of the plurality of extending portions are spaced apart from each other in the winding direction, the power storage cell according to claim 2.

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