Energy storage cell

Abstract

To provide a power storage cell capable of preventing the wound electrode body where the tab lead is located from being subject to a local pressure.SOLUTION: A power storage cell 100 has a wound electrode body 1 that includes: a positive electrode plate 10 (first electrode); a negative electrode plate 20 (second electrode), and a separator 30. The positive electrode plate 10 includes: a positive electrode current collector 11 (current collector); a positive electrode mixture layer 12 (electrode material layer) with a part coated with positive electrode current collector 11; a positive tab lead 13 (tab lead); and an adhesive 14 (buffer material). The positive tab lead 13 is placed at an uncoated area 11c where positive electrode mixture layer 12 is not applied. The adhesive 14 is arranged at a position adjacent to the positive tab lead 13 in the uncoated portion 11c.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] International Publication No. 2018 / 105398 (Patent Document 1) discloses a secondary battery including an electrode body in which a positive electrode and a negative electrode are wound in a spiral shape with a separator interposed therebetween. A lead electrically connected to a positive electrode (negative electrode) terminal is joined to a current collector of the positive electrode (negative electrode).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the electrode body of Patent Document 1 described above, unevenness may be formed due to the thickness of the lead at the location where the lead is provided on the current collector. In this case, when the wound electrode body is constrained by a case or the like due to the unevenness of the wound electrode body, local pressure is applied to the wound electrode body.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a storage battery cell capable of suppressing local pressure from being applied to a wound electrode body on which a tab lead is disposed.

Means for Solving the Problems

[0006] A storage cell according to one aspect of the present disclosure comprises a wound electrode body including a first electrode, a second electrode, and a separator disposed between the first and second electrodes, and a case housing the wound electrode body. The wound electrode body is wound such that the first electrode, the second electrode, and the separator surround a winding axis. The first electrode includes a current collector, an electrode material layer coated on a portion of the current collector, a tab lead provided to protrude from the current collector in the axial direction of the wound electrode body, and a buffer material. The current collector includes an uncoated portion where the electrode material layer is not coated. The tab lead is located in the uncoated portion. The buffer material is located adjacent to the tab lead in the uncoated portion.

[0007] In a power storage cell according to one aspect of this disclosure, as described above, the buffer material is positioned adjacent to the tab lead in the unpainted area. As a result, the area in the unpainted area where the current collector is exposed can be reduced by the presence of the buffer material in the unpainted area where the tab lead is located. Consequently, the formation of irregularities between the areas where the tab lead is located and the areas where the tab lead is not located can be suppressed. This prevents localized pressure from being applied to the wound electrode body due to the irregularities once the wound electrode body is formed.

[0008] In the energy storage cell relating to the first aspect described above, preferably, the elastic modulus of the cushioning material is lower than the elastic modulus of the tab lead. When the first electrode is spread out in a sheet shape, the thickness of the cushioning material in the direction perpendicular to the current collector is greater than or equal to the thickness of the tab lead in the direction perpendicular to the current collector. With this configuration, because the elastic modulus of the cushioning material is lower than that of the tab lead, the cushioning material is more easily deformed than the tab lead. Furthermore, because the thickness of the cushioning material in the direction perpendicular to the tab lead is greater than or equal to the thickness of the tab lead, it is possible to suppress the occurrence of a difference between the thickness of the cushioning material and the thickness of the tab lead when the cushioning material and the tab lead are deformed by the winding of the first electrode.

[0009] In this case, preferably, the elastic modulus of the electrode material layer is lower than that of the tab lead. When the first electrode is spread out in a sheet shape, the thickness of the electrode material layer in the orthogonal direction is greater than or equal to the thickness of the tab lead in the orthogonal direction. With this configuration, the electrode material layer is more easily deformed than the tab lead because its elastic modulus is lower than that of the tab lead. Furthermore, because the thickness of the electrode material layer in the orthogonal direction is greater than or equal to the thickness of the tab lead, it is possible to suppress the occurrence of a difference between the thickness of the electrode material layer and the thickness of the tab lead when the electrode material layer and the tab lead are deformed by the winding of the first electrode.

[0010] In an energy storage cell where the elastic modulus of the electrode material layer is lower than that of the tab lead, preferably, the elastic modulus of the cushioning material is lower than that of the electrode material layer. When the first electrode is spread out in a sheet shape, the thickness of the cushioning material in the orthogonal direction is greater than or equal to the thickness of the electrode material layer in the orthogonal direction. With this configuration, the cushioning material is more easily deformed than the electrode material layer because its elastic modulus is lower than that of the electrode material layer. Furthermore, by ensuring that the thickness of the cushioning material in the orthogonal direction is greater than or equal to the thickness of the electrode material layer, it is possible to suppress the occurrence of a difference between the thickness of the cushioning material and the electrode material layer when the cushioning material and the electrode material layer are deformed by the winding of the first electrode.

[0011] In an energy storage cell where the elastic modulus of the cushioning material is lower than that of the tab lead, preferably, when the first electrode is wound together with the second electrode and the separator, the absolute value of the difference between the thickness of the cushioning material in the radial direction and the thickness of the tab lead in the radial direction is less than or equal to the thickness of the first electrode in the radial direction. With this configuration, the irregularities formed on the wound electrode can be reduced compared to the case where the difference is greater than the thickness of the first electrode.

[0012] In the energy storage cell relating to the first aspect described above, preferably, the unpainted portion is provided at the end of the winding electrode body in the winding direction of the current collector. This configuration makes it possible to suppress the formation of irregularities at the end of the winding electrode body.

[0013] In this case, preferably, the cushioning material includes an adhesive. With this configuration, the first electrode can be easily bonded (fixed) to a member (for example, a separator) radially adjacent to the first electrode at the end of the wound electrode body.

[0014] In the energy storage cell relating to the first aspect described above, preferably, the uncoated portion extends in the axial direction along the winding axis. The buffer material is provided so as to extend along the uncoated portion that extends in the axial direction. With this configuration, the buffer material is provided over a wide area in the axial direction, so the formation of irregularities on the wound electrode body can be further suppressed.

[0015] According to this disclosure, it is possible to suppress localized pressure in the wound electrode body where the tab leads are arranged. [Brief explanation of the drawing]

[0016] [Figure 1] This is a cross-sectional view showing the configuration of a storage cell according to one embodiment. [Figure 2] This is a schematic perspective view showing the configuration of a wound electrode body according to one embodiment. [Figure 3] This is a plan view showing the configuration of a positive electrode plate according to one embodiment. [Figure 4] This is a plan view showing the configuration of a negative electrode plate according to one embodiment. [Figure 5] This figure shows the relationship between the elastic modulus of the positive electrode tab lead, the positive electrode composite layer, and the adhesive. [Figure 6] This is a cross-sectional view along the line VI-VI in Figure 3. [Figure 7] This is a partially enlarged cross-sectional view of a wound electrode body in its wound state. [Figure 8] This is a plan view (Figure 1) showing the configuration of the positive electrode plate according to a modified example of one embodiment. [Figure 9] This is a plan view showing the configuration of a negative electrode plate according to a modified example of one embodiment. [Figure 10] This is a plan view (Figure 2) showing the configuration of the positive electrode plate according to a modified example of one embodiment. [Figure 11] It is a plan view (Figure 3) showing the configuration of a positive electrode plate according to a modification of an embodiment.

Mode for Carrying Out the Invention

[0017] 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.

[0018] FIG. 1 is a cross-sectional view showing the overall configuration of a power storage cell 100 according to an embodiment of the present disclosure. The power storage cell 100 is, for example, a lithium ion battery mounted on a vehicle. Note that the use and type of the power storage cell 100 are not limited to the above example.

[0019] The power storage cell 100 includes a wound electrode body 1, a case 2, a CID (Current Interrupt Device) 3, a positive-side insulating plate 4, a negative-side insulating plate 5, and an insulating layer 6.

[0020] The wound electrode body 1 is housed in the case 2. The case 2 has a cylindrical shape. That is, the power storage cell 100 is a cylindrical battery. The case 2 is formed of, for example, copper or aluminum.

[0021] The wound electrode body 1 includes a positive electrode plate 10, a negative electrode plate 20, and a separator 30. The separator 30 is provided between the positive electrode plate 10 and the negative electrode plate 20. The separator 30 allows ions (for example, lithium ions) to move between the positive electrode plate 10 (positive electrode active material) and the negative electrode plate 20 (negative electrode active material), and separates the positive electrode plate 10 and the negative electrode plate 20. The wound electrode body 1 is composed of a plate group in which the positive electrode plate 10 and the negative electrode plate 20 are wound through the separator 30. Note that the positive electrode plate 10 and the negative electrode plate 20 are examples of the "first electrode" and the "second electrode" of the present disclosure, respectively.

[0022] As shown in Figure 2, the wound electrode body 1 is wound such that the positive electrode plate 10, the negative electrode plate 20, and the separator 30 surround the winding axis α. In Figure 2, the wound electrode body 1 is shown in a state where the winding is slightly unwound, making the winding state of the wound electrode body 1 easier to understand.

[0023] The positive electrode plate 10 includes a positive electrode current collector 11 (see Figure 3), a positive electrode composite layer 12 (see Figure 3), a plurality of positive electrode tab leads 13 (five in this embodiment), and an adhesive 14 (see Figure 3). The negative electrode plate 20 includes a negative electrode current collector 21 (see Figure 4), a negative electrode composite layer 22 (see Figure 4), and a negative electrode tab lead 23. Note that only two positive electrode tab leads 13 are shown in Figure 1. The adhesive 14 and the positive electrode tab leads 13 are examples of the "buffer material" and "tab lead" of this disclosure, respectively. The positive electrode current collector 11 and the positive electrode composite layer 12 are examples of the "current collector" and "electrode material layer" of this disclosure, respectively.

[0024] Referring again to Figure 1, the positive side insulating plate 4 is housed in the case 2. The positive side insulating plate 4 is provided to insulate the wound electrode body 1 (negative electrode plate 20 and separator 30) from the case 2. The positive side insulating plate 4 is provided to cover the positive electrode current collector 11, the negative electrode plate 20, and the separator 30 from the Z1 side.

[0025] The positive side insulating plate 4 has a through hole 4a. The positive electrode tab lead 13 passes through the through hole 4a and is in contact with the conductive film 3b, which will be described later. As a result, the positive electrode tab lead 13 and the conductive film 3b are electrically connected.

[0026] One of the multiple positive electrode tab leads 13 is in contact (welded) with the conductive film 3b, and the remaining positive electrode tab leads 13 are welded to the positive electrode tab lead 13 that is in contact with the conductive film 3b. Alternatively, all of the multiple positive electrode tab leads 13 may be welded to the conductive film 3b.

[0027] The negative side insulating plate 5 is housed in the case 2. The negative side insulating plate 5 is provided to insulate the wound electrode body 1 (positive electrode plate 10 and separator 30) from the case 2. The negative side insulating plate 5 is provided to cover the positive electrode plate 10, the negative electrode current collector 21, and the separator 30 from the Z2 side.

[0028] The negative side insulating plate 5 has a through hole 5a. The negative electrode tab lead 23 is in contact with the bottom 2a of the case 2 by passing through the through hole 5a. As a result, the negative electrode tab lead 23 and the bottom 2a of the case are electrically connected. Consequently, the side portion 2b of the case 2, which is connected to the bottom 2a of the case 2, becomes negatively charged. The side portion 2b is in contact with the negative electrode current collector 21 of the negative electrode plate 20, which is provided on the outermost circumference of the wound electrode body 1.

[0029] CID3 is an element that interrupts the current path by utilizing the increase in internal cell pressure caused by gas generated due to overcharging of the energy storage cell 100. CID3 is provided to seal the opening on the Z1 side of case 2. CID3 has an outer cap 3a, a conductive film 3b, a gasket 3c, and a bottom disk 3d.

[0030] The external cap 3a functions as an external terminal by being electrically connected to an external busbar (not shown). The external cap 3a is provided with a weak portion 3e (thin-walled portion). When the internal pressure of case 2 rises, the external cap 3a is prone to breaking starting from the weak portion 3e. This allows gas to be quickly discharged to the outside of case 2.

[0031] The conductive film 3b is provided to seal the opening on the Z1 side of the case 2. The conductive film 3b includes a protrusion 3f that protrudes toward the wound electrode body 1 side (Z2 side). The protrusion 3f is in contact with the positive electrode tab lead 13. As a result, the conductive film 3b is positively charged. The conductive film 3b is also electrically connected to the outer cap 3a. As a result, the outer cap 3a is also positively charged. The protrusion 3f is provided to penetrate both the gasket 3c and the bottom disk 3d.

[0032] The conductive film 3b, like the outer cap 3a, is provided with a weak portion 3g (thin-walled portion). The conductive film 3b is prone to breaking starting from the weak portion 3g when the internal pressure of case 2 increases. When the conductive film 3b breaks due to the increase in internal pressure, the contact between the conductive film 3b and the positive electrode tab lead 13 is released. As a result, the positive charge of the conductive film 3b is eliminated, and the positive charge of the outer cap 3a is also eliminated. Consequently, the charging and discharging of the energy storage cell 100 is stopped.

[0033] Case 2 is provided with a crimping portion 2c that is crimped onto the outer edge of the outer cap 3a. The insulating layer 6 is provided to insulate the crimping portion 2c from the outer cap 3a (and the conductive film 3b).

[0034] Figure 3 is a view of the positive electrode plate 10 in a sheet-like state, as seen from the Y1 side. The Y direction is perpendicular to the positive electrode current collector 11, which is spread out in a sheet-like state. The positive electrode current collector 11 has a rectangular shape, composed of a long side extending in the X direction and a short side extending in the Z direction. The X direction is an example of the "winding direction" in this disclosure. The Z direction is an example of the "axial direction" in this disclosure. The Y direction is an example of the "orthogonal direction" in this disclosure. The Y direction corresponds to the R direction shown in Figure 1. The R direction is an example of the "radial direction" in this disclosure.

[0035] As shown in Figure 3, the positive electrode composite layer 12 (shaded portion) is coated onto a part of the positive electrode current collector 11. That is, the positive electrode current collector 11 includes a coated portion 11a to which the positive electrode composite layer 12 is coated, and uncoated portions 11b and 11c to which the positive electrode composite layer is not coated. Note that the uncoated portion 11c is an example of the "uncoated portion" in this disclosure.

[0036] In the example shown in Figure 3, the unpainted portion 11c is provided at the X1-side end 11d and the X2-side end 11e of the positive electrode current collector 11. The three unpainted portions 11b are spaced apart from each other in the X direction between the ends 11d and 11e. The painted portion 11a is provided between the unpainted portion 11c and the unpainted portion 11b, and between the unpainted portions 11b themselves. In this embodiment, the X1 side and the X2 side are the winding end side and winding start side of the wound electrode body 1, respectively.

[0037] For example, aluminum is used for the positive electrode current collector 11. The positive electrode composite layer 12 is formed by coating the surface of the positive electrode current collector 11 with a positive electrode slurry and drying it. The positive electrode slurry is a slurry prepared by kneading the materials of the positive electrode composite layer 12 (such as positive electrode active material and binder) with a solvent. The positive electrode composite layer 12 is in close contact with the separator 30 (see Figure 1). The thickness of the positive electrode composite layer 12 is, for example, 0.1 μm or more and 1000 μm or less.

[0038] Each of the three uncoated sections 11b and the two uncoated sections 11c is provided to extend along the Z direction. Each uncoated section 11b has a width W1 in the X direction. Each uncoated section 11c has a width W2 in the X direction. The width W2 of the uncoated section 11c is greater than the width W1 of the uncoated section 11b.

[0039] The positive electrode tab leads 13 are positioned in each of the three unpainted sections 11b and the two unpainted sections 11c. The positive electrode tab leads 13 are provided to protrude axially (towards Z1) from the positive electrode current collector 11. In the X direction, the positive electrode tab leads 13 are located in the center of each unpainted section 11b and each unpainted section 11c.

[0040] In conventional energy storage cells, irregularities may form in the area where leads are provided on the current collector due to the thickness of the leads. In this case, localized pressure is applied to the wound electrode body when it is constrained by a case or the like, due to the irregularities in the wound electrode body.

[0041] Therefore, in this embodiment, the adhesive 14 is positioned adjacent to the positive electrode tab lead 13 in the uncoated portion 11c. Specifically, in the uncoated portion 11c, the adhesive 14 is positioned on both the X1 side and the X2 side of the positive electrode tab lead 13. That is, the positive electrode tab lead 13 in the uncoated portion 11c is positioned so as to be sandwiched in the X direction by the two adhesives 14.

[0042] The adhesive 14 is provided so as to extend along the uncoated portion 11c (positive electrode tab lead 13) that extends in the Z direction. That is, the adhesive 14 is positioned on the surface of the uncoated portion 11c so as to extend in the Z direction.

[0043] Specifically, the adhesive 14 is provided so as to extend from the vicinity of the Z1-side end 11f of the positive electrode current collector 11 to the vicinity of the Z2-side end 11g of the positive electrode current collector 11. The length L1 of the adhesive 14 in the Z direction is greater than the length L2 of the portion of the positive electrode tab lead 13 that is located on the unpainted portion 11c (overlapping with the unpainted portion 11c) in the Z direction. In the example shown in Figure 3, the length L1 is more than twice the length L2. The adhesive 14 may also extend to the position of the end 11f (11g).

[0044] Figure 4 is a view of the negative electrode plate 20 in a sheet-like state, as seen from the Y1 side. As shown in Figure 4, the negative electrode current collector 21, like the positive electrode current collector 11, has a rectangular shape composed of a long side extending in the X direction and a short side extending in the Z direction.

[0045] For example, copper foil is used for the negative electrode current collector 21. The negative electrode composite layer 22 is formed by coating the surface of the negative electrode current collector 21 with a negative electrode slurry and drying it. The negative electrode slurry is a slurry prepared by kneading the materials of the negative electrode composite layer 22 (negative electrode active material and binder, etc.) with a solvent. The negative electrode composite layer 22 is in close contact with the separator 30 (see Figure 1). The thickness of the negative electrode composite layer 22 is, for example, 0.1 μm or more and 1000 μm or less.

[0046] The negative electrode composite layer 22 is coated onto a portion of the negative electrode current collector 21. That is, the negative electrode current collector 21 includes a coated portion 21a to which the negative electrode composite layer 22 is coated, and an uncoated portion 21b to which the negative electrode composite layer 22 is not coated. The negative electrode tab lead 23 is located in the uncoated portion 21b. The negative electrode tab lead 23 is provided to protrude axially (towards Z2) from the negative electrode current collector 21.

[0047] Figure 5 shows the relationship between the elastic moduli of the positive electrode tab lead 13, the positive electrode composite layer 12, and the adhesive 14. As shown in Figure 5, the elastic moduli are highest in the order of positive electrode tab lead 13, positive electrode composite layer 12, and adhesive 14. In other words, they are less prone to deformation in the order of positive electrode tab lead 13, positive electrode composite layer 12, and adhesive 14.

[0048] Figure 6 is a cross-sectional view along the line VI-VI in Figure 3. As shown in Figure 6, the positive electrode current collector 11 has a thickness t11 in the Y direction. The positive electrode composite layer 12 has a thickness t12 in the Y direction. The positive electrode tab lead 13 has a thickness t13 in the Y direction. The adhesive 14 has a thickness t14 in the Y direction. Note that the thickness t12 of the positive electrode composite layer 12, the thickness t13 of the positive electrode tab lead 13, and the thickness t14 of the adhesive 14 are all greater than the thickness t11 of the positive electrode current collector 11.

[0049] The thickness t14 of the adhesive 14 is greater than the thickness t12 of the positive electrode composite layer 12 (t14>t12). Also, the thickness t12 of the positive electrode composite layer 12 is greater than the thickness t13 of the positive electrode tab lead 13 (t12>t13). In other words, the thicknesses are greater in the order of adhesive 14, positive electrode composite layer 12, and positive electrode tab lead 13 (t14>t12>t13). Therefore, the thicknesses are arranged in order from lowest to highest elastic modulus (from easiest to most deformable).

[0050] The difference Δt between the thickness t14 of the adhesive material 14 and the thickness t13 of the positive electrode tab lead 13 is greater than the thickness t11 of the positive electrode current collector 11 (Δt>t11). Also, the difference Δt is smaller than the thickness t13 of the positive electrode tab lead 13 (Δt<t13). For example, the difference Δt is at most 1 / 3 of the thickness t13 of the positive electrode tab lead 13 (Δt≦t13 / 3). Note that the difference Δt may be at most the thickness t11 of the positive electrode current collector 11. Also, the value of 1 / 3 above is merely an example and is not limited to this example.

[0051] FIG. 7 is a cross-sectional view of the state where the positive electrode plate 10 is wound together with the separator 30 and the negative electrode plate 20. In this state, due to the above-described difference in elastic modulus, the amount of deformation increases in the order of the adhesive material 14, the positive electrode composite layer 12, and the positive electrode tab lead 13. Thereby, the difference between the thickness t24 of the adhesive material 14 in the radial direction (R direction) and the thickness t23 of the positive electrode tab lead 13 in the radial direction becomes smaller than the thickness t21 of the positive electrode current collector 11 in the radial direction.

[0052] In the example shown in FIG. 7, the thickness t24 of the adhesive material 14, the thickness t23 of the positive electrode tab lead 13, and the thickness t22 of the positive electrode composite layer 12 in the radial direction are substantially equal to each other. Therefore, the above-described difference is substantially 0. Note that the above-described difference may be greater than 0 and smaller than the thickness t21 of the positive electrode current collector 11.

[0053] As described above, in the present embodiment, the adhesive material 14 is disposed at a position adjacent to the positive electrode tab lead 13 in the non-coated portion 11c. It is possible to suppress the formation of a space where no member is disposed at a position adjacent to the positive electrode tab lead 13. As a result, it is possible to suppress the formation of irregularities at a position adjacent to the positive electrode tab lead 13. Thereby, it is possible to suppress the local application of pressure to the wound electrode body 1 due to the above-described irregularities in the state where the wound electrode body 1 is formed.

[0054] In the above embodiment, an example is shown in which adhesive 14 is placed on the unpainted portion 11c provided at each of the X1-side end 11d and X2-side end 11e of the positive electrode current collector 11, but the disclosure is not limited thereto. The unpainted portion 11c may be provided at locations other than the ends 11d and 11e of the positive electrode current collector 11. In the positive electrode plate 110 shown in Figure 8, an unpainted portion 11c is provided between the ends 11d and 11e of the positive electrode current collector 11 (for example, in the central part), where adhesive 14 is placed together with the positive electrode tab lead 13. Although not shown, the unpainted portion 11c may be provided at only one of the X1-side end 11d and X2-side end 11e of the positive electrode current collector 11. Note that the positive electrode plate 110 is an example of the "first electrode" of the disclosure.

[0055] In the above embodiment, an example is shown in which adhesive 14 is placed on the unpainted portion 11c of the positive electrode current collector 11, but the disclosure is not limited thereto. Adhesive 14 may also be placed on the negative electrode current collector plate. In the example shown in Figure 9, the negative electrode current collector 21 of the negative electrode plate 120 is provided with an unpainted portion 21c in addition to the painted portion 21a and the unpainted portion 21b. A negative electrode tab lead 23 and adhesive 14 are placed in the unpainted portion 21c. The negative electrode tab lead 23 is sandwiched between two adhesives 14 in the unpainted portion 21c. The unpainted portion 21c is provided at both the X1 side end 21d and the X2 side end 21e of the negative electrode current collector 21. The negative electrode plate 120 is an example of the "second electrode" of this disclosure.

[0056] In the above embodiment, an example is shown where the adhesive 14 and the positive electrode tab lead 13 are adjacent in the X direction, but the disclosure is not limited thereto. In the uncoated portion 11h of the positive electrode plate 210 shown in Figure 10, the adhesive 114 is arranged adjacent to the positive electrode tab lead 13 not only on both sides of the positive electrode tab lead 13 in the X direction, but also on the Z2 side of the positive electrode tab lead 13. In the uncoated portion 11i, the adhesive 114 is arranged adjacent to the positive electrode tab lead 13 on the Z2 side of the positive electrode tab lead 13. In the uncoated portion 11h, the adhesive 14 and adhesive 114 may be combined and arranged as a single adhesive. Furthermore, the positive electrode plate 210 and the adhesive 114 are examples of the "first electrode" and "cushioning material" of this disclosure, respectively.

[0057] In the above embodiment, an example was shown in which the thickness t14 of the adhesive 14 is greater than the thickness t13 of the positive electrode tab lead 13, but the disclosure is not limited thereto. The thickness t14 of the adhesive 14 may be equal to the thickness t13 of the positive electrode tab lead 13. Also, the thickness t12 of the positive electrode composite layer 12 may be equal to the thickness t13 of the positive electrode tab lead 13. The thickness t14 of the adhesive 14 may be equal to the thickness t12 of the positive electrode composite layer 12.

[0058] In the above embodiment, an example is shown in which adhesive 14 is placed on the uncoated portion 11c, but the disclosure is not limited thereto. A non-adhesive cushioning material (for example, rubber) may be placed on the uncoated portion 11c.

[0059] In the above embodiment, an example was shown in which the adhesive 14 extends axially along the uncoated portion 11c, but the disclosure is not limited thereto. For example, in the positive electrode plate 310 shown in Figure 11, the adhesive 214 is placed only at the Z1-side end of the uncoated portion 11j. Also, the adhesive 214 is placed only near the center in the Z direction of the uncoated portion 11k. The positive electrode plate 310 and the adhesive 214 are examples of the "first electrode" and "cushioning material" of this disclosure, respectively.

[0060] In the above embodiment, an example is shown in which multiple positive electrode tab leads 13 are provided, but the disclosure is not limited thereto. Only one positive electrode tab lead 13 may be provided.

[0061] In the above embodiment, an example is shown in which two adhesives 14 are placed on the uncoated portion 11c, but the disclosure is not limited thereto. Only one adhesive 14 may be placed on the uncoated portion 11c.

[0062] Furthermore, the configurations of the above embodiments and each of the above modified examples may be combined with each other.

[0063] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of symbols]

[0064] 1. Winding electrode body, 2. Case, 10, 110, 210, 310. Positive electrode plate (first electrode), 11. Positive electrode current collector (current collector), 11a. Coated part, 11c, 11h, 11i, 11j, 11k. Uncoated part, 11d, 11e. End part, 12. Positive electrode composite layer (electrode material layer), 13. Positive electrode tab lead (tab lead), 14, 114, 214. Adhesive (cushioning material), 20, 120. Negative electrode plate (second electrode), 30. Separator, 100. Energy storage cell, R direction (radial direction), t11. Thickness (thickness of positive electrode current collector plate in the orthogonal direction), t12. Thickness (thickness of positive electrode composite layer in the orthogonal direction), t13. Thickness (thickness of positive electrode tab lead in the orthogonal direction), t14. Thickness (thickness of adhesive in the orthogonal direction), t21 Thickness (thickness of positive electrode current collector plate in the radial direction), t23 Thickness (thickness of positive electrode tab lead in the radial direction), t24 Thickness (thickness of adhesive in the radial direction), X direction (winding direction), Y direction (orthogonal direction), Z direction (axial direction), α Winding axis.

Claims

1. A wound electrode body including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode, The case comprises the aforementioned wound electrode body, The wound electrode body is wound such that the first electrode, the second electrode, and the separator surround the winding axis. The first electrode is Current collector and, An electrode material layer coated on a part of the current collector, A tab lead is provided so as to protrude from the current collector in the axial direction of the wound electrode body, Including cushioning material, The current collector includes an uncoated portion where the electrode material layer is not coated. The tab lead is positioned in the uncoated area, The cushioning material is positioned adjacent to the tab lead in the uncoated portion. The elastic modulus of the cushioning material is lower than that of the electrode material layer. The elastic modulus of the electrode material layer is lower than that of the tab lead. In a state in which the first electrode is spread out in a sheet shape, the thickness of the buffer material in the orthogonal direction perpendicular to the current collector is greater than or equal to the thickness of the electrode material layer in the orthogonal direction. A storage cell in which the thickness of the electrode material layer in the orthogonal direction is greater than or equal to the thickness of the tab lead in the orthogonal direction.

2. The energy storage cell according to claim 1, wherein, in a state in which the first electrode is wound together with the second electrode and the separator, the absolute value of the difference between the thickness of the cushioning material in the radial direction of the wound electrode body and the thickness of the tab lead in the radial direction is less than or equal to the thickness of the current collector in the radial direction.

3. The energy storage cell according to claim 1 or 2, wherein the unpainted portion is provided at the end of the winding electrode body in the winding direction of the current collector.

4. The energy storage cell according to claim 3, wherein the cushioning material includes an adhesive.

5. The uncoated portion extends in the axial direction along which the winding axis extends. The energy storage cell according to claim 1 or 2, wherein the cushioning material is provided so as to extend along the uncoated portion that extends in the axial direction.

6. The energy storage cell according to claim 1 or 2, wherein the length of the cushioning material in the axial direction is at least twice the length of the portion of the tab lead that is arranged in the uncoated portion in the axial direction.

7. The energy storage cell according to claim 1 or 2, wherein, when the first electrode is spread out in a sheet-like state, the difference between the thickness of the cushioning material and the thickness of the tab lead in the orthogonal direction is greater than the thickness of the current collector in the orthogonal direction.

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