Energy storage cell

Abstract

To provide a power storage cell that can reduce shortage of an electrolytic solution in a wound assembly.SOLUTION: A power storage cell 1 includes an electrode assembly 100, a cell case that houses the electrode assembly, and an electrolytic solution contained in the cell case. The electrode assembly 100 includes: a wound assembly 101 in which the positive electrode sheet and the negative electrode sheet are wound with the separator interposed therebetween; a first tape 141 attached to one end portion of the wound assembly 101 in an axial direction of the wound assembly 101; and a second tape 142 attached to the other end portion of the wound assembly 101 in the axial direction. Force of fixing the wound assembly 101 by the first tape 141 is smaller than force of fixing the wound assembly by the second tape 142.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] International Publication No. 2018 / 168628 discloses a nonaqueous electrolyte secondary battery including a wound body in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween, and a battery case that accommodates the wound body and a nonaqueous electrolyte. The end of the wound body is fixed with tape. Specifically, tape is attached to one end and the other end of the wound body in the axial direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 168628 Summary of the Invention [Problem to be solved by the invention]

[0004] In the nonaqueous electrolyte secondary battery described in WO 2018 / 168628, the electrolyte leaks out from the wound body, particularly during high-rate charge and discharge, raising concerns about a shortage of electrolyte in the wound body.

[0005] An object of the present disclosure is to provide an electricity storage cell that can suppress a shortage of electrolyte in a wound body. [Means for solving the problem]

[0006] A storage cell according to one aspect of the present disclosure includes an electrode body, a cell case that houses the electrode body, and an electrolyte housed in the cell case, wherein the electrode body includes a wound body formed by winding a positive electrode sheet and a negative electrode sheet with a separator interposed therebetween, a first tape attached to one end of the wound body in an axial direction, and a second tape attached to the other end of the wound body in the axial direction, and the fixing force of the first tape on the wound body is smaller than the fixing force of the second tape on the wound body. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide an electricity storage cell that can suppress a shortage of electrolyte in a wound body. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically illustrating a storage cell according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a front view schematically showing an electrode body. [Figure 3] FIG. 3 is a cross-sectional view of a first tape. [Figure 4] FIG. 4 is a cross-sectional view of a second tape. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present disclosure will be described with reference to the accompanying drawings, in which the same or corresponding elements are designated by the same reference numerals.

[0010] Fig. 1 is a partial cross-sectional view schematically showing a storage cell according to an embodiment of the present disclosure. Fig. 2 is a front view schematically showing an electrode assembly. This storage cell 1 is preferably mounted on a vehicle.

[0011] As shown in Figures 1 and 2, the energy storage cell 1 includes an electrode assembly 100, a cell case 200, an external terminal 300, a positive electrode current collector plate 410, a negative electrode current collector plate 420, an insulating member 500, and an electrolyte (not shown).

[0012] As shown in FIG. 2, the electrode assembly 100 has a wound body 101, a first tape 141, and a second tape 142.

[0013] The wound body 101 has a positive electrode sheet 110, a negative electrode sheet 120, and a separator 130. The wound body 101 is formed by winding the positive electrode sheet 110 and the negative electrode sheet 120 with the separator 130 interposed between them around a winding core A (see FIG. 1).

[0014] The positive electrode sheet 110 includes a positive electrode current collector foil 112 and a positive electrode active material layer 114 .

[0015] The positive electrode current collector foil 112 is made of a metal such as aluminum, and has a main region 112a and an end region 112b.

[0016] The main region 112a is a region of the positive electrode current collector foil 112 where the positive electrode active material layer 114 is provided. As shown in Fig. 1, the main regions 112a are arranged so as to overlap each other in the radial direction of the electrode body 100 (the left-right direction in Fig. 1).

[0017] The end region 112b is a region of the positive electrode current collector foil 112 where the positive electrode active material layer 114 is not provided. As shown in Fig. 1, the end region 112b is formed outside (on the upper side in Fig. 1) the main region 112a in the axial direction of the electrode body 100 (the vertical direction in Fig. 1).

[0018] The end region 112b has a plurality of tabs separated from one another in the circumferential direction of the electrode body 100. Each tab 112b1 leans inward in the radial direction. The upper surface of each tab forms a substantially flat surface. A positive electrode current collector plate 410 is connected to each tab by welding or the like.

[0019] The negative electrode sheet 120 has a negative electrode current collector foil 122 made of a metal such as copper, and a negative electrode active material layer 124 provided on the surface of the negative electrode current collector foil 122 .

[0020] The structure of the negative electrode current collector foil 122 is substantially the same as that of the positive electrode current collector foil 112. Therefore, the description of the negative electrode current collector foil 122 will be simplified. That is, the negative electrode current collector foil 122 has a main region 122a in which a negative electrode active material layer 124 is provided, and an end region 122b formed outside the main region 122a in the axial direction (the lower side in FIG. 1). The end region 122b has multiple tabs separated from each other in the circumferential direction, and each tab leans inward in the radial direction. A negative electrode current collector plate 420 is connected to each tab by welding or the like.

[0021] The separator 130 is disposed between the positive electrode sheet 110 and the negative electrode sheet 120. More specifically, the separator 130 is disposed only between the main region 112a of the positive electrode sheet 110 and the main region 122a of the negative electrode sheet 120, which are adjacent to each other in the radial direction. The separator 130 is made of an insulating material and allows ions to pass through.

[0022] The first tape 141 is attached to one end of the wound body 101 in the axial direction of the wound body 101 (the vertical direction in FIG. 2). The second tape 142 is attached to the other end of the wound body 101 in the axial direction. In this embodiment, the first tape 141 is provided below the second tape 142 in the vertical direction. That is, the first tape 141 is attached to the lower end of the wound body 101, and the second tape 142 is attached to the upper end of the wound body 101. As shown in FIG. 2, the first tape 141 and the second tape 142 are attached to the wound body 101 so as to straddle the end 139 of the wound body 101. The first tape 141 and the second tape 142 may be connected in a circular shape in the circumferential direction of the wound body 101.

[0023] 3, the first tape 141 has a first base material layer 141a and a first adhesive layer 141b provided on the first base material layer 141a. The first base material layer 141a is made of, for example, polypropylene (PP), polyimide (PI), polyethylene (PE), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), etc. The first adhesive layer 141b is made of, for example, an acrylic or silicone adhesive material.

[0024] 4, the second tape 142 has a second base material layer 142a and a second adhesive layer 142b provided on the second base material layer 142a. The second base material layer 142a is made of the same material as the first base material layer 141a. The first adhesive layer 141b is made of the same material as the first adhesive layer 141b.

[0025] The fixing force of the wound body 101 by the first tape 141 is smaller than the fixing force of the wound body 101 by the second tape 142. In this embodiment, as shown in FIG. 2, the adhesive area of ​​the first adhesive layer 141b to the wound body 101 is set smaller than the adhesive area of ​​the second adhesive layer 142b to the wound body 101.

[0026] However, the adhesive area of ​​the first adhesive layer 141b to the wound body 101 and the adhesive area of ​​the second adhesive layer 142b to the wound body 101 may be set equal to each other, and the adhesive strength of the first adhesive layer 141b may be set smaller than the adhesive strength of the second adhesive layer 142b. For example, if each adhesive layer 141b, 142b is made of a silicone-based adhesive material, the mixing ratio of silicone rubber, which ensures adhesion, and silicone resin, which ensures adhesion, may be different in each adhesive layer 141b, 142b. That is, the mixing ratio of silicone resin in the first adhesive layer 141b may be set smaller than the mixing ratio of silicone resin in the second adhesive layer 142b. Alternatively, the molecular weight of the polymer in the first adhesive layer 141b may be set smaller than the molecular weight of the polymer in the second adhesive layer 142b.

[0027] The cell case 200 houses the electrode assembly 100. An electrolyte (not shown) is housed inside the cell case 200. The cell case 200 is sealed. The cell case 200 is made of a metal such as aluminum. The cell case 200 has a cylindrical portion 210, a top wall 220, and a bottom wall 230.

[0028] The cylindrical portion 210 surrounds the outer circumferential surface of the electrode body 100 .

[0029] The top wall 220 is connected to the upper end of the cylindrical portion 210. A through hole for inserting the external terminal 300 is formed in the center of the top wall 220.

[0030] The bottom wall 230 is connected to the lower end of the cylindrical portion 210 by welding or the like. The bottom wall 230 is in contact with the negative electrode current collector plate 420.

[0031] The external terminal 300 is formed above the top wall 220. In this embodiment, the external terminal 300 constitutes a positive electrode external terminal, and the cell case 200 constitutes a negative electrode external terminal.

[0032] The insulating member 500 provides insulation between the cell casing 200 and the external terminal 300. The insulating member 500 has an upper insulating portion 510 and a lower insulating portion 520.

[0033] The upper insulating portion 510 is provided on the upper surface of the top wall 220. The upper insulating portion 510 is interposed between the upper surface of the top wall 220 and the external terminal 300.

[0034] The lower insulating portion 520 is provided on the lower surface of the top wall 220. The lower insulating portion 520 is interposed between the positive electrode current collector plate 410 and the cell case 200.

[0035] As described above, in the energy storage cell 1 of this embodiment, the force with which the first tape 141 fastens the wound body 101 is smaller than the force with which the second tape 142 fastens the wound body 101, and therefore the space for holding the electrolyte at one end of the wound body 101 is larger than the space for holding the electrolyte at the other end of the wound body 101. This makes it easier for the electrolyte that has flowed out of the wound body 101 during charging and discharging, etc., to return to the wound body 101. This prevents a shortage of electrolyte in the wound body 101.

[0036] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0037] [Aspect 1] An electrode body; a cell case that accommodates the electrode assembly; an electrolyte solution contained in the cell case; The electrode body is a wound body formed by winding a positive electrode sheet and a negative electrode sheet with a separator interposed therebetween; a first tape attached to one end of the wound body in the axial direction of the wound body; a second tape attached to the other end of the wound body in the axial direction, The energy storage cell, wherein the force with which the first tape fixes the wound body is smaller than the force with which the second tape fixes the wound body.

[0038] In this energy storage cell, the force with which the first tape secures the wound body is smaller than the force with which the second tape secures the wound body, so the electrolyte retention space at one end of the wound body is larger than the electrolyte retention space at the other end of the wound body. This makes it easier for the electrolyte that leaks out of the wound body during charging and discharging to return to the wound body. This prevents a shortage of electrolyte in the wound body.

[0039] [Aspect 2] 2. The energy storage cell according to claim 1, wherein the first tape is provided below the second tape in the vertical direction.

[0040] In this embodiment, the electrolyte retention space is relatively large in the lower part of the wound body, so that the electrolyte pooled in the lower part of the cell case easily flows into the wound body from the lower part of the wound body.

[0041] [Aspect 3] the first tape has a first adhesive layer; the second tape has a second adhesive layer; 3. The energy storage cell according to aspect 1 or 2, wherein an adhesive area of ​​the first adhesive layer with respect to the wound body is smaller than an adhesive area of ​​the second adhesive layer with respect to the wound body.

[0042] In this embodiment, the adhesive areas of the adhesive layers with respect to the wound body are different, so the force with which the first tape fixes the wound body is smaller than the force with which the second tape fixes the wound body.

[0043] [Aspect 4] the first tape has a first adhesive layer; the second tape has a second adhesive layer; 3. The energy storage cell according to aspect 1 or 2, wherein the adhesive strength of the first adhesive layer to the wound body is smaller than the adhesive strength of the second adhesive layer to the wound body.

[0044] In this embodiment, the adhesive strength of each adhesive layer to the wound body differs, so the force with which the first tape fixes the wound body is smaller than the force with which the second tape fixes the wound body.

[0045] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0046] 1 storage cell, 100 electrode body, 101 wound body, 110 positive electrode sheet, 112 positive electrode current collector foil, 112a main region, 112b end region, 114 positive electrode active material layer, 120 negative electrode sheet, 122 negative electrode current collector foil, 122a main region, 122b end region, 124 negative electrode active material layer, 130 separator, 141 first tape, 141a first base material layer, 141b first adhesive layer, 142 second tape, 142a second base material layer, 142b second adhesive layer, 200 cell case, 210 case body, 220 top wall, 230 bottom wall, 300 external terminal, 410 positive electrode current collector plate, 420 negative electrode current collector plate, 510 insulating member.

Claims

1. An electrode body; a cell case that accommodates the electrode assembly; an electrolyte solution contained in the cell case; The electrode body is a wound body formed by winding a positive electrode sheet and a negative electrode sheet with a separator interposed therebetween; a first tape attached to one end of the wound body in the axial direction of the wound body; a second tape attached to the other end of the wound body in the axial direction, the first tape is provided below the second tape in the vertical direction, a fixing force of the wound body by the first tape being smaller than a fixing force of the wound body by the second tape.

2. the first tape has a first adhesive layer; the second tape has a second adhesive layer; The energy storage cell according to claim 1 , wherein an adhesive area of ​​the first adhesive layer with respect to the wound body is smaller than an adhesive area of ​​the second adhesive layer with respect to the wound body.

3. the first tape has a first adhesive layer; the second tape has a second adhesive layer; The energy storage cell according to claim 1 , wherein an adhesive strength of the first adhesive layer to the wound body is smaller than an adhesive strength of the second adhesive layer to the wound body.

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