Power storage cell

Abstract

To provide a power storage cell that can restrain the local application of load to a wound electrode body.SOLUTION: A power storage cell includes: a wound electrode body in which an electrode sheet and a separator laminated on one another is wound around a winding axis line; a buffer member provided so as to surround the wound electrode body from an outer peripheral side of the wound electrode body; and a case housing the wound electrode body and the buffer member.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 (Japanese Patent No. 4225639) discloses an electricity storage device including a wound electrode body provided with a tab lead. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4225639 Summary of the Invention [Problem to be solved by the invention]

[0004] The wound electrode body of Patent Document 1 is provided with a tab lead. The provision of the tab lead may cause a bulge to be formed on the outer circumferential surface of the wound electrode body due to the thickness of the tab lead. In this case, when the wound electrode body is restrained by a case or the like, a load is locally applied to the wound electrode body (bulge).

[0005] The present disclosure has been made to solve the above-mentioned problems, and has an object to provide an energy storage cell that is capable of suppressing localized application of a load to a wound electrode body. [Means for solving the problem]

[0006] [1] A wound electrode body in which an electrode sheet and a separator are stacked on each other and wound around a winding axis; a buffer member provided so as to surround the wound electrode body from an outer periphery side of the wound electrode body; a case that houses the wound electrode body and the buffer member.

[0007] [2] The storage cell according to [1], wherein the buffer member is made of a porous material.

[0008] [3] The storage cell according to [1] or [2], wherein an uneven portion is formed on an outer peripheral surface of the case.

[0009] [4] The winding axis extends in the axial direction, The storage cell according to [3], wherein the uneven portion is provided at least across one end to the other end of a range in the axial direction in which the wound electrode body is arranged.

[0010] [5] The energy storage cell according to [3] or [4], wherein the uneven portion is provided so as to circumferentially surround the wound electrode body. Effect of the Invention

[0011] According to the present disclosure, it is possible to suppress localized application of a load to the wound electrode body. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing a configuration of a storage cell according to a first embodiment. [Diagram 2] FIG. 1 is a schematic perspective view showing the configuration of a wound electrode body according to a first embodiment. [Diagram 3] FIG. 11 is a perspective view showing the configuration of a storage cell according to a third embodiment. [Figure 4] FIG. 11 is a plan view of the storage cell according to the third embodiment, as viewed from the Z1 side. [Diagram 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 11 is a perspective view showing another configuration of the electricity storage cell according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 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 characters, and the description thereof will not be repeated.

[0014] [First embodiment] 1 is a perspective view showing a configuration of an energy storage cell 100 according to a first embodiment of the present disclosure. The energy storage cell 100 is, for example, a lithium ion battery mounted on a vehicle. Note that the use and type of the energy storage cell 100 are not limited to the above examples.

[0015] The energy storage cell 100 includes a wound electrode body 10, a buffer member 11, and a case 12. The wound electrode body 10 and the buffer member 11 are housed in the case 12.

[0016] 2 is a schematic perspective view showing the configuration of the wound electrode body 10. The wound electrode body 10 includes a positive electrode plate 110, a negative electrode plate 111, and a separator 112. The separator 112 is provided between the positive electrode plate 110 and the negative electrode plate 111. That is, the positive electrode plate 110, the separator 112, and the negative electrode plate 111 are stacked on top of each other. The separator 112 separates the positive electrode plate 110 and the negative electrode plate 111 while allowing ions (e.g., lithium ions) to move between the positive electrode plate 110 (positive electrode active material) and the negative electrode plate 111 (negative electrode active material). The wound electrode body 10 is composed of an electrode plate group in which the positive electrode plate 110 and the negative electrode plate 111 are wound with the separator 112 interposed therebetween. The positive electrode plate 110, the separator 112, and the negative electrode plate 111 are wound around a winding axis α. In this specification, the direction in which the winding axis extends is defined as the Z direction. Each of the positive electrode plate 110 and the negative electrode plate 111 is an example of an "electrode sheet" in the present disclosure. The Z direction is an example of an "axial direction" in the present disclosure.

[0017] The positive electrode plate 110 includes a positive electrode current collector and a positive electrode mixture layer. The positive electrode current collector is made of a metal material such as aluminum or an aluminum alloy.

[0018] The positive electrode mixture layer includes a positive electrode active material and a binder. The positive electrode active material includes, for example, LiCoO2, LiNo2, LiMn2O4, etc. The thickness of the positive electrode mixture layer is, for example, 0.1 μm or more and 1000 μm or less. The positive electrode mixture layer is formed on both the front and back surfaces of the positive electrode current collector plate, but may be formed on one surface.

[0019] The negative electrode plate 111 includes a negative electrode current collector and a negative electrode composite layer. The negative electrode current collector includes, for example, a metal material such as copper.

[0020] The negative electrode mixture layer includes a negative electrode active material and a binder. The negative electrode active material is, for example, graphite. The thickness of the negative electrode mixture layer is, for example, 0.1 μm or more and 1000 μm or less. The negative electrode mixture layer is formed on both the front and back surfaces of the negative electrode current collector plate, but may be formed on one surface.

[0021] The case 12 has a cylindrical shape. In other words, the power storage cell 100 is a cylindrical battery. The case 12 is made of copper, aluminum, or the like.

[0022] In a conventional energy storage cell, the provision of a tab lead may cause a bulge to be formed on the outer peripheral surface of the wound electrode body due to the thickness of the tab lead. In this case, when the wound electrode body is restrained by a case or the like, a load is locally applied to the wound electrode body (bulge).

[0023] Therefore, in the first embodiment, the buffer member 11 is provided so as to surround the wound electrode body 10 from the outer periphery side of the wound electrode body 10. Even if a bulge is formed on the outer periphery surface of the wound electrode body 10, the provision of the buffer member 11 allows the buffer member 11 to absorb the bulge and suppress localized load. In addition, the buffer member 11 can reduce pressure from the case 12. As a result, the buffer member 11 fixes the wound electrode body 10 and the case 12 while suppressing localized pressure on the wound electrode body 10, thereby improving the vibration resistance of the wound electrode body 10.

[0024] 1 again, the case 12 includes a top plate 120, a bottom surface 121, and a side wall 122. The top plate 120 is provided so as to cover the wound electrode body 10 and the buffer member 11 from the Z1 side. The bottom surface 121 is provided so as to support the wound electrode body 10 and the buffer member 11 from the Z2 side. The side wall 122 connects the top plate 120 and the bottom surface 121. The side wall 122 has a circular ring shape centered on the winding axis α (see FIG. 2).

[0025] As described above, in the first embodiment, the buffer member 11 is provided between the wound electrode body 10 and the case 12. This allows the buffer member 11 to absorb the bulge even if a bulge is formed on the outer peripheral surface of the wound electrode body 10. As a result, it is possible to suppress the load from being locally applied to the wound electrode body 10 from the case 12.

[0026] [Second embodiment] Next, a second embodiment of the present disclosure will be described. In the second embodiment, the buffer member 11 is made of a porous material. The same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description will not be repeated.

[0027] The case 12 also contains an electrolyte (not shown). Because the buffer member 11 is made of a porous material, when the electrolyte is injected into the wound electrode body 10 from one side in the axial direction, the electrolyte can be introduced into the inside of the wound electrode body 10 through the buffer member 11. In addition, since the porous material has excellent liquid retention properties, it is possible to prevent the electrolyte from drying up in the energy storage cell 100.

[0028] Furthermore, by providing the porous buffer member 11 between the wound electrode body 10 and the case 12, for example, gas generated within the case 12 can be easily discharged.

[0029] An example of the porous member is a sponge-like member such as urethane foam.

[0030] The other configurations are similar to those of the first embodiment, and therefore will not be described repeatedly.

[0031] [Third embodiment] Next, a third embodiment of the present disclosure will be described with reference to Fig. 3 to Fig. 6. In the third embodiment, uneven portions 122a (protrusions 122b, recesses 122c) are formed on the outer peripheral surface (side wall 122) of case 12. The same configurations as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description will not be repeated.

[0032] FIG. 3 is a perspective view showing a configuration of a storage cell 100 according to a third embodiment of the present disclosure. A concave-convex portion 122a is formed on a side wall 122. The concave-convex portion 122a includes convex portions 122b and concave portions 122c arranged alternately in the Z direction. That is, a plurality of convex portions 122b and a plurality of concave portions 122c are provided. The concave portions 122c are formed between the convex portions 122b arranged in the Z direction. The concave-convex portion 122a is an example of the "convex-convex portion" of the present disclosure. The convex portions 122b and the concave portions 122c are examples of the "convex portion" and the "concave portion" of the present disclosure, respectively.

[0033] 4 is a plan view of the energy storage cell 100 as viewed from the Z1 side. The uneven portion 122a is provided so as to circumferentially surround the wound electrode body 10. In other words, each of the multiple protrusions 122b is formed so as to extend circumferentially and has an annular shape.

[0034] Fig. 5 is a cross-sectional view taken along line VV in Fig. 4. The uneven portion 122a of the side wall 122 is provided at least from one end S1 to the other end S2 of the range S in the Z direction in which the wound electrode body 10 is arranged. The range in the Z direction in which the uneven portion 122a is provided may be wider than the range S in which the wound electrode body 10 is arranged. Furthermore, the uneven portion 122a is arranged so as to cover the entire wound electrode body 10 (range S) when viewed along the radial direction (R direction).

[0035] The protrusions 122b aligned in the axial direction are spaced apart by a distance D1. Note that the distance D1 between the protrusions 122b means the distance between the apexes of the protrusions 122b.

[0036] As described above, in this embodiment, the uneven portion 122a is formed on the side wall 122 of the case 12. This increases the strength of the energy storage cell 100 and enables the energy storage cell 100 to be made thinner. In addition, the uneven portion 122a functions as a spring, making it possible to absorb expansion and contraction of the wound electrode body 10.

[0037] In the above embodiment, an example has been described in which the uneven portion 122a of the case 12 is formed over the entire range S of the wound electrode body 10, but the present disclosure is not limited to this. For example, as shown in Fig. 6, the uneven portion 122a may be formed only on the Z1 side and the Z2 side of the range S. In other words, it is not necessary for the uneven portion to be formed near the center of the range S.

[0038] In the above embodiment, an example has been described in which the uneven portion 122a of the case 12 circumferentially surrounds the wound electrode body 10, but the present disclosure is not limited to this. The uneven portion 122a may be provided so as to partially surround the wound electrode body 10. In other words, the protruding portion 122b may have an arc shape.

[0039] The other configurations are similar to those of the first embodiment, and therefore will not be described repeatedly.

[0040] The configurations of the above-described embodiments may be combined with each other.

[0041] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0042] 10 wound electrode body, 11 buffer member, 12 case, 100 storage cell, 110 positive electrode plate (electrode sheet), 111 negative electrode plate (electrode sheet), 112 separator, 120 top plate, 121 bottom surface, 122 side wall, 122a uneven portion, 122b convex portion, 122c concave portion, D1 spacing, S range, S1 one end, S2 other end, Z direction (axial direction), α winding axis.

Claims

1. a wound electrode body in which an electrode sheet and a separator are stacked on each other and wound around a winding axis; a buffer member provided so as to surround the wound electrode body from an outer periphery side of the wound electrode body; a case that houses the wound electrode body and the buffer member.

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

3. The energy storage cell according to claim 1 , wherein an uneven portion is formed on an outer peripheral surface of the case.

4. The winding axis extends in the axial direction, The energy storage cell according to claim 3 , wherein the uneven portion is provided at least across one end to the other end of a range in the axial direction in which the wound electrode body is arranged.

5. The energy storage cell according to claim 3 , wherein the uneven portion is provided so as to circumferentially surround the wound electrode body.

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