Energy storage device

Abstract

To provide a power storage device capable of suppressing both vibrations of the power storage device to a vehicle and contact of an upper cover with a power storage stack.SOLUTION: A power storage device 1 includes: a power storage stack 100 including a plurality of power storage cells 110; a lower case 200 accommodating the power storage stack; an upper cover 300 covering the power storage stack; an outside elastic body 500 made of an elastic material and provided on an outer surface of the upper cover; and an inside elastic body 600 made of an elastic material and provided on an inner surface of the upper cover. The inside elastic body has a spring constant larger than a spring constant of the outside elastic body.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a power storage device.

Background Art

[0002] For example, Japanese Patent Laid-Open No. 10-69893 discloses a battery pack comprising a case that accommodates a battery, and a rubber sponge provided on an inner surface of an upper case of the case.

Prior Art Literature

Patent Literature

[0003]

Patent Literature 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] When a power storage device such as that described in Japanese Patent Laid-Open No. 10-69893 is mounted on a vehicle, it is required to reduce vibration of the power storage device relative to the vehicle. Further, there is a concern that the upper cover may contact the power storage stack when a downward load is input to the power storage device from above.

[0005] An object of the present disclosure is to provide a power storage device capable of suppressing both vibration of the power storage device relative to a vehicle and contact of an upper cover with a power storage stack.

Means for Solving the Problem

[0006] A power storage device according to one aspect of the present disclosure comprises: a power storage stack including a plurality of power storage cells; a lower case that accommodates the power storage stack; an upper cover that covers the power storage stack; an outer elastic body made of an elastic material and provided on an outer surface of the upper cover; and an inner elastic body made of an elastic material and provided on an inner surface of the upper cover, wherein the inner elastic body has a spring constant larger than that of the outer elastic body. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an energy storage device that can suppress both vibration of the energy storage device relative to the vehicle and contact of the upper cover with the energy storage stack. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view of an energy storage device in one embodiment of the present disclosure. [Figure 2] Figure 1 is a schematic perspective view showing the energy storage device with the upper cover removed. [Figure 3] This is a cross-sectional view taken along line III-III in Figure 1. [Figure 4] This is a schematic perspective view showing the outer and inner elastic bodies. [Figure 5] This figure schematically shows the results of a CAE analysis of the stress distribution generated in the outer elastic body when a uniform load is applied to its upper surface. [Figure 6] This is a schematic plan view showing a modified example of the outer elastic body. [Figure 7] This is a schematic plan view showing a modified example of the outer elastic body. [Figure 8] This is a schematic plan view showing a modified example of the outer elastic body. [Figure 9] This is a schematic plan view showing a modified example of the outer elastic body. [Figure 10] This is a schematic perspective view showing a modified example of the outer elastic body. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same number.

[0010] Figure 1 is a schematic perspective view of an energy storage device in one embodiment of the present disclosure. Figure 2 is an exploded perspective view of the energy storage device shown in Figure 1. Figure 3 is a cross-sectional view taken along line III-III in Figure 1. This energy storage device 1 is mounted, for example, on the bottom 10 of a vehicle (see Figure 3).

[0011] As shown in Figures 1 to 3, the energy storage device 1 comprises at least one energy storage stack 100, a lower case 200, an upper cover 300, a plate material 400, at least one outer elastic body 500, and at least one inner elastic body 600.

[0012] At least one energy storage stack 100 includes multiple energy storage stacks 100. In this embodiment, the energy storage device 1 includes six energy storage stacks 100. However, the number of energy storage stacks 100 is not limited to six.

[0013] Each energy storage stack 100 includes a plurality of energy storage cells 110 arranged in a first direction. Examples of energy storage cells 110 include lithium-ion batteries. Each energy storage cell 110 may also be a solid-state battery using a solid electrolyte. As shown in Figure 2, each energy storage cell 110 is formed as a flattened rectangular parallelepiped. The length of the energy storage cell 110 in a second direction, which is perpendicular to both the first direction and the vertical direction, is longer than the length of the energy storage cell 110 in the vertical direction. The plurality of energy storage stacks 100 are arranged with spacing in the first direction and with spacing in the second direction.

[0014] The lower case 200 houses multiple energy storage stacks 100. The lower case 200 is open upwards. The lower case 200 has a bottom wall 210, a peripheral wall 220, and a load transmission section 230.

[0015] The bottom wall 210 supports each energy storage stack 100. The bottom wall 210 may include a cooling plate that contacts the bottom of each energy storage stack 100.

[0016] The peripheral wall 220 rises from the peripheral edge of the bottom wall 210. The peripheral wall 220 surrounds the plurality of electricity storage stacks 100.

[0017] The load transmission portion 230 transmits a downwardly input load to the upper cover 300 to the bottom wall 210. The load transmission portion 230 rises from the bottom wall 210. As shown in Figure 2, the load transmission portion 230 is arranged between a pair of electricity storage stacks 100 adjacent to each other in the first direction. The load transmission portion 230 partitions between the pair of electricity storage stacks 100 adjacent to each other in the first direction. The load transmission portion 230 is connected to the peripheral wall 220. That is, the load transmission portion 230 has a function of reinforcing the peripheral wall 220. As shown in Figure 3, the height of the load transmission portion 230 from the bottom wall 210 is set to be substantially the same as the height of the peripheral wall 220 from the bottom wall 210.

[0018] The upper cover 300 covers the plurality of electricity storage stacks 100. The upper cover 300 is open downward. The upper cover 300 accommodates the electricity storage stacks 100 together with the lower case 200. The peripheral edge of the upper cover 300 is fixed to the lower case 200 by bolts or the like. The upper cover 300 includes a top wall 310 arranged above the plurality of electricity storage stacks 100. The top wall 310 may be formed in a flat plate shape.

[0019] The plate member 400 presses the plurality of electricity storage stacks 100 toward the bottom wall 210. The plate member 400 may be formed in a flat plate shape. The plate member 400 is made of synthetic resin or the like. The plate member 400 is arranged so as to straddle across the plurality of electricity storage stacks 100 and the load transmission portion 230. As shown in Figure 3, the peripheral edge of the plate member 400 is in contact with the upper surface of the peripheral wall 220.

[0020] At least one outer elastic body 500 includes a plurality of outer elastic bodies 500. Each outer elastic body 500 is provided on the outer surface of the upper cover 300. Each outer elastic body 500 is made of an elastic material such as urethane. Each outer elastic body 500 is formed in a flat rectangular parallelepiped shape. The plurality of outer elastic bodies 500 are spaced apart from each other. As shown in Figures 2 and 3, each outer elastic body 500 is positioned to overlap with the load transmission section 230 in the vertical direction, i.e., above the load transmission section 230.

[0021] At least one inner elastic body 600 includes a plurality of inner elastic bodies 600. Each inner elastic body 600 is provided on the inner surface of the upper cover 300. Each inner elastic body 600 is made of an elastic material such as urethane. Each inner elastic body 600 is formed in a flat rectangular parallelepiped shape. Each inner elastic body 600 may be formed in the same shape as the outer elastic body 500. The plurality of inner elastic bodies 600 are spaced apart from each other. As shown in Figures 2 and 3, each inner elastic body 600 is positioned to overlap the outer elastic body 500 in the vertical direction. Each inner elastic body 600 is positioned above the load transmission section 230. In this embodiment, each inner elastic body 600 is sandwiched between the top wall 310 and the plate material 400 of the upper cover 300.

[0022] The spring constant [N / mm] of each inner elastic body 600 is greater than the spring constant [N / mm] of each outer elastic body 500. Note that the "spring constant" includes both static and dynamic spring constants. The measurement method for static and dynamic spring constants is based on JIS K 6385. Specifically, the spring constant is calculated based on the relationship between the load acting on each elastic body 500 and 600 and the deflection of each elastic body 500 and 600 at that time.

[0023] The hardness (Type C) of each inner elastic body 600 is greater than the hardness (Type C) of each outer elastic body 500. The hardness (Type C) is measured according to JIS K 7312. That is, the hardness is calculated based on the reaction force acting from the test piece to the indenter when the test piece of each elastic body 500 and 600 is pressed with an indenter.

[0024] As shown in Figure 3, the thickness t6 of each inner elastic body 600 is greater than the thickness t5 of each outer elastic body 500. However, the thickness t6 of each inner elastic body 600 may be less than or equal to the thickness t5 of each outer elastic body 500.

[0025] One of the elastic bodies, the outer elastic body 500 and the inner elastic body 600, has an identification element that can be distinguished from the other elastic body, the outer elastic body 500 and the inner elastic body 600. In this embodiment, the outer elastic body 500 has an identification element 510 (see Figures 3 and 4). However, the inner elastic body 600 may also have an identification element. Note that the identification element 510 is not shown in Figures 1 and 2.

[0026] As shown in Figures 3 and 4, the identification element 510 is made up of a notch. The outer elastic body 500 has a long side portion 501 and a short side portion 502 in a plan view, and the notch is formed in the center of the long side portion 501. The notch has a shape that is recessed inward in a direction parallel to the short side portion 502. As shown in Figure 4, the inner elastic body 600 also has a long side portion 601 and a short side portion 602. The position of the notch will be explained with reference to Figure 5.

[0027] Figure 5 schematically shows the CAE analysis results of the stress distribution generated in the outer elastic body 500 when a uniform load is applied to the upper surface of the outer elastic body 500. Figure 5 shows that the highest stress occurs in region A, and the stress decreases in the order of region A, region B, region C, region D, and region E. As shown in Figure 5, the stress generated in the central part of the long side portion 501 is relatively small. Therefore, it can be seen that the cushioning function of the outer elastic body 500 is substantially maintained even when a notch is formed in the central part of the long side portion 501. Accordingly, in this embodiment, as shown in Figure 4, a notch as an identification element 510 is formed in the central part of the long side portion 501.

[0028] As described above, in the energy storage device 1 of this embodiment, since an outer elastic body 500 is provided on the outer surface of the upper cover 300, vibration of the energy storage device 1 relative to the vehicle when the energy storage device 1 is mounted on the bottom 10 of the vehicle is effectively suppressed. Furthermore, since an inner elastic body 600 having a relatively large spring constant is provided on the inner surface of the upper cover 300, collision of the top wall 310 with the energy storage stack 100 when a downward external force acts on the top wall 310 of the upper cover 300 is suppressed.

[0029] Since the outer elastic body 500 has an identification element 510, it becomes easy to distinguish between the outer elastic body 500 and the inner elastic body 600. Therefore, misplacement of the outer elastic body 500 and the inner elastic body 600 during the assembly of the energy storage device 1 is suppressed.

[0030] The form of the identification element 510 is not limited to the examples of the above embodiment, and various modifications are possible. Modifications of the identification element 510 will be described below with reference to Figures 6 to 10.

[0031] As shown in Figure 6, the identification element 510 may be formed in a curved shape that is convex inward.

[0032] As shown in Figure 7, the identification element 510 may be formed at the corner of the outer elastic body 500.

[0033] As shown in Figure 8, the identification element 510 may consist of a display portion connected to the surface of the outer elastic body 500. Alternatively, the identification element 510 may consist of a through hole formed in the central part of the outer elastic body 500.

[0034] As shown in Figure 9, the identification element 510 may be composed of a different color from the color of the inner elastic body 600. In Figure 9, the surface color of the outer elastic body 500 is indicated by diagonal lines to show that it is different from the surface color of the inner elastic body 600.

[0035] As shown in Figure 10, the outer elastic body 500 has a protruding portion that extends from the inner elastic body 600 in a plan view when the outer elastic body 500 and the inner elastic body 600 are superimposed, and the identification element 510 may be composed of the protruding portion.

[0036] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0037] [Aspect 1] A storage stack containing multiple energy storage cells, A lower case housing the aforementioned energy storage stack, An upper cover covering the aforementioned energy storage stack, It consists of an elastic material and an outer elastic body provided on the outer surface of the upper cover, It comprises an inner elastic body made of an elastic material and provided on the inner surface of the upper cover, An energy storage device wherein the inner elastic body has a spring constant greater than the spring constant of the outer elastic body.

[0038] In this energy storage device, an outer elastic body with a relatively small spring constant is provided on the outer surface of the upper cover, so that vibrations of the energy storage device relative to the vehicle when the energy storage device is mounted on the vehicle are effectively suppressed, and an inner elastic body with a relatively large spring constant is provided on the inner surface of the upper cover, so that collisions of the upper cover with the energy storage stack when a downward external force acts on the upper cover are suppressed.

[0039] [Aspect 2] The energy storage device according to embodiment 1, wherein one of the outer elastic body and the inner elastic body includes an identification element that can be distinguished from the other elastic body of the outer elastic body and the inner elastic body.

[0040] In this embodiment, since one elastic body can be distinguished from the other elastic body, misplacement of the outer and inner elastic bodies during the assembly of the energy storage device is suppressed.

[0041] [Aspect 3] Each of the outer elastic body and the inner elastic body is formed in a rectangular parallelepiped shape having a long side and a short side when viewed from above. The energy storage device according to embodiment 2, wherein the identification element is a notch formed in the center of the long side portion of one of the elastic bodies.

[0042] In this embodiment, identification becomes possible while substantially maintaining buffering properties.

[0043] [Aspect 4] The energy storage device according to embodiment 2, wherein the identification element is composed of a different color from the color of the other elastic body.

[0044] [Aspect 5] Each of the outer elastic body and the inner elastic body is formed in a rectangular parallelepiped shape having a long side and a short side when viewed from above. The one elastic body has a protruding portion that, when the outer elastic body and the inner elastic body are superimposed, protrudes from the other elastic body in a plan view. The energy storage device according to embodiment 2, wherein the identification element is composed of the protruding portion.

[0045] [Aspect 6] The energy storage device according to embodiment 1, wherein the inner elastic body is positioned to overlap with the outer elastic body in the vertical direction.

[0046] [Aspect 7] The aforementioned lower case is The bottom wall and It has a load transmission unit that transmits a load applied downward to the upper cover to the bottom wall, The load transmission unit is erected from the bottom wall and is positioned to the side of the energy storage stack. The energy storage device according to embodiment 6, wherein the inner elastic body is positioned above the load transmission section.

[0047] In this embodiment, a downward load applied to the upper cover is received by the bottom wall via the inner elastic body and load transmission section, thereby suppressing damage to the energy storage stack caused by the load.

[0048] [Aspect 8] The energy storage stack is further provided with a plate material that presses it toward the bottom wall, The plate material is arranged to straddle the energy storage stack and the load transmission section, The energy storage device according to embodiment 7, wherein the inner elastic body is sandwiched between the upper cover and the plate material.

[0049] In this embodiment, a downward load applied to the upper cover is more effectively transmitted to the bottom wall.

[0050] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of this disclosure is defined by the claims rather than the description of the embodiments above, and includes all modifications within the meaning and scope equivalent to the claims. [Explanation of symbols]

[0051] 1 Energy storage device, 100 Energy storage stack, 110 Energy storage cell, 200 Lower case, 210 Bottom wall, 220 Peripheral wall, 230 Load transmission section, 300 Upper cover, 310 Top wall, 400 Plate material, 500 Outer elastic body, 501 Long side section, 502 Short side section, 510 Identification element, 600 Inner elastic body, 601 Long side section, 602 Short side section.

Claims

1. A storage stack containing multiple energy storage cells, A lower case housing the aforementioned energy storage stack, An upper cover that covers the aforementioned energy storage stack, It consists of an elastic material and an outer elastic body provided on the outer surface of the upper cover, It comprises an inner elastic body made of an elastic material and provided on the inner surface of the upper cover, The inner elastic body has a spring constant that is greater than the spring constant of the outer elastic body. The outer elastic body and the inner elastic body each include an identification element that is distinguishable from the other elastic body, Each of the outer elastic body and the inner elastic body is formed in a rectangular parallelepiped shape having a long side and a short side when viewed from above. The identification element is formed by a notch formed in the center of the long side of one of the elastic bodies, in the energy storage device.

2. A storage stack comprising a plurality of energy storage cells, A lower case housing the aforementioned energy storage stack, An upper cover covering the aforementioned energy storage stack, It consists of an elastic material and an outer elastic body provided on the outer surface of the upper cover, It comprises an inner elastic body made of an elastic material and provided on the inner surface of the upper cover, The inner elastic body has a spring constant that is greater than the spring constant of the outer elastic body. The outer elastic body and the inner elastic body each include an identification element that is distinguishable from the other elastic body, An energy storage device wherein the identification element is composed of a different color from the color of the other elastic body.

3. A storage stack comprising a plurality of energy storage cells, A lower case housing the aforementioned energy storage stack, An upper cover that covers the aforementioned energy storage stack, It consists of an elastic material and an outer elastic body provided on the outer surface of the upper cover, It comprises an inner elastic body made of an elastic material and provided on the inner surface of the upper cover, The inner elastic body has a spring constant that is greater than the spring constant of the outer elastic body. The outer elastic body and the inner elastic body each include an identification element that is distinguishable from the other elastic body, Each of the outer elastic body and the inner elastic body is formed in a rectangular parallelepiped shape having a long side and a short side when viewed from above. The one elastic body has a protruding portion that, when the outer elastic body and the inner elastic body are superimposed, protrudes from the other elastic body in a plan view. The identification element is comprised of the protruding portion, in the energy storage device.

4. A storage stack comprising a plurality of energy storage cells, A lower case housing the aforementioned energy storage stack, An upper cover that covers the aforementioned energy storage stack, It consists of an elastic material and an outer elastic body provided on the outer surface of the upper cover, It comprises an inner elastic body made of an elastic material and provided on the inner surface of the upper cover, The inner elastic body has a spring constant that is greater than the spring constant of the outer elastic body. The inner elastic body is positioned so as to overlap with the outer elastic body in the vertical direction. The aforementioned lower case is The bottom wall and It has a load transmission unit that transmits a load applied downward to the upper cover to the bottom wall, The load transmission unit is erected from the bottom wall and is positioned to the side of the energy storage stack. The inner elastic body is an energy storage device positioned above the load transmission section.

5. The energy storage stack is further provided with a plate material that presses it toward the bottom wall, The plate material is arranged to straddle the energy storage stack and the load transmission section, The energy storage device according to claim 4, wherein the inner elastic body is sandwiched between the upper cover and the plate material.

Images