Energy storage device

Abstract

To provide an energy storage device that can suppress damage to the corners of the exterior body. [Solution] The energy storage device 1 comprises an electrode body 10 having a positive electrode and a negative electrode, and an outer casing 20 that houses the electrode body 10. The outer casing 20 has a first bulge and a second bulge formed by folding the outer casing 20 and bulging out from the outer casing 20. The corners 200 of the outer casing 20 face the corners 100 of the electrode body 10, and the first bulges 212, 222 and the second bulges 213, 223 are arranged on either side of the corners 200 of the outer casing 20.

Description

[TECHNICAL FIELD]

[0001] The present disclosure relates to an electricity storage device. [BACKGROUND ART]

[0002] Patent Document 1 discloses an electricity storage device in which a pouch outer package houses an electrode body. In this technique, a bulging portion that alleviates external impact is formed on the bottom surface of the pouch outer package. [PRIOR ART DOCUMENT] [PATENT DOCUMENT]

[0003] [Patent Document 1] Japanese Patent Laid-Open No. 2018-56030 [SUMMARY OF THE INVENTION] [Problem to be Solved by the Invention]

[0004] However, the corners of the electrode body are pressed against the corners of the pouch outer package by external impact. As a result, the corners of the pouch outer package may be damaged.

[0005] The present disclosure has been made in view of the above, and an object of the present disclosure is to provide an electricity storage device capable of suppressing damage to corners of an outer package. [Means for Solving the Problem]

[0006] The electricity storage device according to the present disclosure is an electricity storage device including: an electrode body having a positive electrode and a negative electrode; and an outer package that houses the electrode body, wherein the outer package has a first bulging portion and a second bulging portion that are formed by folding the outer package and bulge from the outer package, a corner of the outer package faces a corner of the electrode body, and the first bulging portion and the second bulging portion are arranged with the corner of the outer package interposed therebetween. [Effect of the Invention]

[0007] According to this disclosure, the effect is to suppress damage to the corners of the exterior body. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing the configuration of an energy storage device according to one embodiment of the present disclosure. [Figure 2] Figure 2 is an enlarged view including region R1 in Figure 1. [Figure 3] Figure 3 is a partially enlarged view showing the configuration of an energy storage device according to one embodiment of the present disclosure. [Figure 4] Figure 4 is a schematic diagram of the thickness direction of an energy storage device according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] Hereinafter, an energy storage device according to one embodiment of the present disclosure will be described with reference to the drawings. Note that some components in the following embodiment are substituted or substantially identical to those easily substituted by those skilled in the art. Furthermore, it should be noted that the drawings are schematic, and the dimensional relationships and ratios of each element may differ from reality. Even between drawings, there may be differences in dimensional relationships and ratios. In addition, directions may be explained using the XYZ Cartesian coordinate system in the drawings.

[0010] [Configuration of the energy storage device] Figure 1 is a schematic diagram showing the configuration of an energy storage device according to one embodiment of the present disclosure. Figure 2 is an enlarged view including region R1 of Figure 1. Figure 3 is a partially enlarged view showing the configuration of an energy storage device according to one embodiment of the present disclosure. Figure 4 is a schematic diagram of the energy storage device in the thickness direction according to one embodiment of the present disclosure.

[0011] The energy storage device 1 shown in Figures 1 to 4 is used in battery packs for all-solid-state batteries installed in electric vehicles such as HEVs (Hybrid Electric Vehicles), PHEVs (Plug-in Hybrid Electric Vehicles), and EVs (Electric Vehicles). The battery pack including the energy storage device 1 is a bipolar type energy storage device in which multiple energy storage devices 1 are stacked. For example, the energy storage device 1 is a rechargeable secondary battery such as a lithium-ion battery, and uses a solid electrolyte as its electrolyte. In the following, the X direction of the energy storage device 1 will be described as the width direction of the energy storage device 1, the Y direction of the energy storage device 1 will be described as the depth direction of the energy storage device 1, and the Z direction of the energy storage device 1 will be described as the stacking direction or thickness direction.

[0012] The energy storage device 1 shown in Figure 1 comprises an electrode body 10 and an outer casing 20 that houses the electrode body 10.

[0013] The electrode body 10 is formed by stacking a plurality of positive electrode plates, a plurality of negative electrode plates, and separators, etc., in a predetermined pattern. The electrode body 10 is formed by bonding positive electrode leads and negative electrode leads (not shown) to the positive electrode plates and negative electrode plates, respectively.

[0014] The outer casing 20 houses the electrode body 10. Specifically, the outer casing 20 houses the electrode body 10 such that its corners 200 face the corners 100 of the electrode body 10. The outer casing 20 comprises a first laminate sheet 21 and a second laminate sheet 22. Each of the first laminate sheet 21 and the second laminate sheet 22 has welded portions 211 and 221 that are provided and extend in the peripheral direction (width direction and depth direction) of the first laminate sheet 21 and the second laminate sheet 22. Each of the first laminate sheet 21 and the second laminate sheet 22 is heat-sealed at three predetermined sides of the welded portions 211 and 221 while housing the electrode body 10. Then, after the non-aqueous electrolyte is injected from the remaining side of each of the first laminate sheet 21 and the second laminate sheet 22, the welded portion 211 and welded portion 221 on the remaining side are heat-sealed to form the outer casing 20 into a pouch shape and the inside is sealed. That is, because the inside of the outer casing 20 is under reduced pressure, it is in close contact with the electrode body 10. For this reason, the outer casing 20 is susceptible to force from the electrode body 10 and other external forces being applied to the corners 200 of the outer casing 20, making it highly likely that the outer casing 20 will be damaged.

[0015] Each of the first laminate sheet 21 and the second laminate sheet 22 is made by laminating a metal layer and a resin layer. Preferably, each of the first laminate sheet 21 and the second laminate sheet 22 has at least a resin layer for heat welding on the inner surface side of the outer casing 20, and the resin layers may be placed on both sides of the metal layer, and an adhesive layer may be placed between the metal layer and the resin layer. In addition, each of the first laminate sheet 21 and the second laminate sheet 22 uses aluminum and aluminum alloys as the metal layer. Each of the first laminate sheet 21 and the second laminate sheet 22 uses polyolefin resins such as polypropylene and polyethylene, polyamide resins such as nylon, and polyester resins such as polyethylene terephthalate as the resin layer. Urethane resin or polyolefin resin is used for the adhesive layer. In order to improve the adhesion between the polyolefin resin and the metal layer, it is preferable to use a carboxylic acid-modified polyolefin resin to which carboxyl groups have been added for the polyolefin resin of the adhesive layer.

[0016] Furthermore, the outer casing 20 has first bulges 212, 222 and second bulges 213, 223 which are formed by folding the outer casing 20 and bulging out from the outer casing 20. Specifically, each of the first bulges 212, 222 and the second bulges 213, 223 is formed in an accordion shape by folding the first laminate sheet 21 and the second laminate sheet 22. For example, each of the first bulges 212, 222 and the second bulges 213, 223 is formed in an accordion shape by folding the excess portion (excess sheet) of the first laminate sheet 21 and the second laminate sheet 22 which has been pre-embossed.

[0017] Each of the first bulging portions 212, 222 and the second bulging portions 213, 223 is formed spaced apart by several millimeters in the vertical direction from each of the welded portion 211 and the welded portion 221 (see FIGS. 3 and 4). Specifically, as shown in FIG. 4, a vertical length H1 in the thickness direction of each of the first bulging portions 212, 222 and the second bulging portions 213, 223 is formed so as to be at maximum equal to a width H2 of a surplus portion where the first laminate sheet 21 and the second laminate sheet 22 are pre-embossed.

[0018] Furthermore, each of the first bulging portions 212, 222 and the second bulging portions 213, 223 is arranged at four positions across the four corners 200 of the exterior body 20. In addition, each of the first bulging portions 212, 222 and the second bulging portions 213, 223 is arranged so as to be at the same position in the lamination direction in the vertical direction. Of course, as long as each of the first bulging portions 212, 222 and the second bulging portions 213, 223 is arranged across the corner 200 of the exterior body 20, they may be at positions different from the same position in the lamination direction in the vertical direction.

[0019] Each of the first bulging portions 212, 222 and the second bulging portions 213, 223 configured as described above is formed to be stretchable in the width direction (X direction) of the power storage device 1 or the depth direction (Y direction) of the power storage device 1 according to an external force applied to the power storage device 1. That is, in the power storage device 1, when the corner 100 of the electrode body 10 is pressed against the corner 200 of the exterior body 20, the folded first bulging portions 212, 222 and second bulging portions 213, 223 are expanded. Therefore, the force applied from the electrode body 10 to the exterior body 20 is absorbed by the first bulging portions 212, 222 and the second bulging portions 213, 223. As a result, in the power storage device 1, concentration of force applied to the corner 200 of the exterior body 20 is suppressed, and damage to the corner 200 of the exterior body 20 can be suppressed.

[0020] According to the embodiment described above, since the first bulging portions 212, 222 and the second bulging portions 213, 223 are arranged across the corner 200 of the exterior body 20, damage to the corner 200 of the exterior body 20 can be suppressed.

[0021] Note that, in one embodiment, the outer package is configured to be formed of two sheets, the first laminate sheet 21 and the second laminate sheet 22. However, the configuration is not limited thereto, and the outer package 20 may be formed into a pouch shape by folding one laminate sheet and heat-welding the folded sheet.

[0022] Further effects and modifications can be easily derived by those skilled in the art. Broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and equivalents thereof.

[0023] Although several embodiments of the present application have been described in detail above with reference to the drawings, these are illustrative, and the present invention can be implemented in other forms with various modifications and improvements based on the knowledge of those skilled in the art, including the aspects described in the disclosure section of the present invention. Description of Reference Signs

[0024] 1 power storage device 10 electrode assembly 20 outer package 21 first laminate sheet 22 second laminate sheet 100, 200 corner portion 211, 221 welded portion 212, 222 first bulging portion 213, 223 second bulging portion

Claims

1. It is an energy storage device, An electrode body having a positive electrode and a negative electrode, An outer casing for housing the electrode body, Equipped with, The exterior body is, The exterior body is folded and has a first bulge and a second bulge that bulge out from the exterior body, The corners of the exterior body are It faces the corner of the electrode body, The first bulge and the second bulge are, The following are arranged on either side of the corner of the exterior body: Energy storage device.

2. The energy storage device according to claim 1, The exterior body is, It further has a welded portion that extends circumferentially from the exterior body and is welded by heat welding, The first bulge is, The above-mentioned welded portion is provided vertically above and below, The second bulge is, The above-mentioned welded portion is provided vertically above and below, Energy storage device.

3. The energy storage device according to claim 2, The first bulge and the second bulge are, Located near the corner of the exterior body, Energy storage device.

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