JP7024526B2 - Power storage device - Google Patents

Description

The present invention relates to a power storage device.

The power storage device generally has a power storage element group composed of a plurality of power storage elements, and is classified into a compression type or a compressionless type depending on the arrangement and holding mode of the power storage element group. In the compression type power storage device, spacers for electrical insulation are arranged between each power storage element, the power storage element group is sandwiched between sheet metal members called end plates, and pressure is restrained by using a band or the like. For example, in Patent Document 1, a beam member such as a binding band is provided in order to pressurize and restrain a group of power storage elements housed in the exterior body.

Since the compression type power storage device requires a member for holding the power storage element such as a spacer, an end plate, and a band, the size tends to be large as a whole, and the volumetric energy density of the power storage device tends to decrease. On the other hand, the compressionless type power storage device does not require a member such as a spacer, an end plate, and a band because the power storage element group including a plurality of power storage elements insulated by an insulating sheet or the like is housed in the exterior body. Therefore, since the maximum size of the power storage element can be secured in the power storage device, the volumetric energy density of the power storage device can be increased.

Japanese Unexamined Patent Publication No. 2017-152412

It is known that a power storage device can exhibit stable performance by pressure-constraining a group of power storage elements. However, the power storage elements often have slightly different sizes due to variations in manufacturing tolerances, expansion due to aging, and the like. Therefore, it is necessary to perform pressure restraint according to the size of different power storage element groups. In the compression type power storage device, the power storage element group can be pressure-constrained by an end plate, a band, or the like, but in the compression-less type power storage device, these cannot be easily pressure-constrained because these are not provided. Therefore, in the compressionless type power storage device, it is necessary to provide an alternative structure for pressurizing and restraining the power storage element group.

An object of the present invention is to provide a compressionless power storage device that enables pressure restraint that can secure stable battery performance without using a restraint member such as a band.

The present invention accommodates a group of energy storage elements in which a plurality of energy storage elements are arranged in an array direction, and the first side wall facing the first side wall parallel to the arrangement direction and facing the direction intersecting the arrangement direction. An exterior body having a second side wall, a base end portion protruding from the inner surface of the second side wall and having a first width, and a second width protruding from the top surface of the base end portion and narrower than the first width. Provided is a power storage device including a stepped rib having a tip having a tip portion thereof.

According to this configuration, the base end portion of the stepped rib reinforces the second side wall of the exterior body, and the tip end portion of the stepped rib pressurizes and restrains the power storage element group. When the power storage element group is housed in the exterior body, the stepped rib can be crushed by being pressed by the power storage element group. As a mode of being crushed, since the tip portion is thinner than the base end portion, the base end portion is not crushed and the tip portion is crushed. As a result, even if the size of the power storage element group housed in the exterior body is not constant, the internal volume of the exterior body changes appropriately according to the power storage element group depending on the degree of crushing of the tip portion. Therefore, since the power storage element group is housed in the exterior body without any gap, the power storage element group can be pressure-constrained to the extent that stable battery performance can be ensured without using a restraining member such as a band. Further, since the shape of the base end portion is maintained, the strength of the exterior body can be ensured. Further, since the base end portion for reinforcement and the tip end portion for pressure restraint are not formed separately but integrally formed, space saving can be realized.

The exterior body further has a bottom wall connected to the first side wall and the second side wall, and the base end portion and the tip end portion may both be connected to the bottom wall.

According to this configuration, since the stepped rib is connected to the bottom wall, the strength of the exterior body can be improved. Further, when designing the exterior body by resin molding, the mold design becomes easy, that is, the exterior body after molding can be easily removed from the mold.

The amount of protrusion of the tip portion may gradually decrease as the distance from the bottom wall increases.

According to this configuration, since the amount of protrusion of the tip portion is smaller toward the upper part of the exterior body, a large space can be secured inside the exterior body. Since the electrical components and the like are arranged on the upper part of the exterior body, a wide space for arranging the electrical components and the like can be secured by the above configuration.

The maximum protrusion amount of the tip portion may be 0.1 mm or more.

According to this configuration, it is possible to cope with variations in the manufacturing tolerance of the power storage element and size changes such as expansion of the power storage element due to long-term use. That is, by setting the protrusion amount of the tip portion to 0.1 mm or more, it is possible to surely realize the crushing of the tip portion, and it is possible to cope with these size changes depending on the degree of crushing.

The first width may be twice or more as compared with the second width.

According to this configuration, even if the stepped rib is pressed by the power storage element, the shape of the base end portion for reinforcement is maintained, and only the tip portion for pressurization restraint can be crushed. Therefore, it is possible to maintain the strength of the exterior body and pressurize and restrain the power storage element group.

According to the present invention, in a compressionless power storage device, it is possible to perform pressure restraint that can secure stable battery performance without using a restraint member such as a band.

Perspective view of the power storage device according to the embodiment of the present invention. An exploded perspective view of the power storage device Perspective view of the exterior Perspective view with a part of the exterior cut out Enlarged view of the part shown in the circle of FIG. Schematic side view of stepped ribs Schematic cross-sectional view of the stepped ribs along lines VII-VII of FIG. Schematic cross-sectional view showing how the stepped rib of FIG. 7 is crushed. Schematic side view of the stepped rib of the exterior body in the power storage device of the first modification. Schematic cross-sectional view of the stepped rib of the exterior body in the power storage device of the second modification. Schematic cross-sectional view of the stepped rib of the exterior body in the power storage device of the third modification.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view of a power storage device 1 according to an embodiment of the present invention.

The power storage device 1 has a substantially rectangular parallelepiped outer body 5 composed of a synthetic resin case 10 and a lid 20. The lid 20 functions as a lid of the case 10, and an electrode terminal 21 is attached to the upper portion thereof. The power storage device 1 is electrically connected to another electric element via the electrode terminal 21 and functions as a battery.

The case 10 has a bottom wall 11, two first side walls 12 rising from the bottom wall 11 and facing each other, and two second side walls 13 rising from the bottom wall 11 and facing orthogonally to the first side wall 12. That is, the case 10 is a box shape that opens upward.

Referring to FIG. 2, a power storage element group 30, an electrical component 40, and a pressure equalizing plate 50 are housed in the exterior body 5.

The power storage element group 30 includes a plurality of power storage elements 31 arranged side by side in a predetermined arrangement direction and an insulating sheet 32 covering the power storage element 31, and has a substantially rectangular parallelepiped shape having a short side surface 30a and a long side surface 30b. .. Each power storage element 31 also has a substantially rectangular parallelepiped shape having a short side surface 31a and a long side surface 31b. In the present embodiment, each power storage element 31 has the same shape, the long side surfaces 31b of the power storage elements 31 at both ends in the arrangement direction form the short side surface 30a of the power storage element group 30, and the short side surface 31a of the power storage element 31 is a surface. They are arranged together to form the long side surface 30b of the power storage element group 30. Hereinafter, the arrangement direction of the power storage elements 31 is also referred to as an X direction. Further, the height direction of the power storage device 1 is also referred to as a Z direction, and the directions orthogonal to the X direction and the Z direction are also referred to as a Y direction. According to this regulation, the first side wall 12 is arranged parallel to the X direction and the Z direction, and the second side wall 13 is arranged parallel to the Y direction and the Z direction.

The electrical component 40 is arranged above the power storage element group 30 and is housed in the case 10. The electrical component 40 is formed by arranging various electronic components on the substrate 41. In a plan view, the substrate 41 has a rectangular shape and is fixed to the case 10. Specifically, the substrate 41 is positioned with respect to the case 10 by inserting the pin 12a (see FIG. 3) of the case 10 into the pin hole 41a arranged at the edge of the substrate 41.

Pressure equalizing plates 50 are arranged on both sides of the power storage element group 30 in the X direction. The pressure equalizing plate 50 is a thin metal plate, and when the power storage element group 30 is housed in the case 10, it comes into contact with the short side surface 30a of the power storage element group 30, and the power storage element group 30 receives a partial push from the case 10. It has a function of spreading the pressure over the entire short side surface 30a of the power storage element group 30 to equalize the pressure. Therefore, the pressure equalizing plate 50 has the same size as the short side surface 30a of the power storage element group 30. The pressure equalizing plate 50 may be omitted if necessary.

Referring to FIG. 3, the reinforcing rib 12b projects in the Y direction (inside the case 10) from the inner surface of the first side wall 12. The amount of protrusion of the reinforcing rib 12b in the Y direction is such that when the power storage element group 30 is housed in the case 10, it does not interfere with the long side surface 30b of the power storage element group 30. Further, the reinforcing ribs 12b extend in the Z direction and are provided side by side in the X direction. One end of each reinforcing rib 12b is connected to the bottom wall 11, and the other end is terminated in the case 10. At the other end of some of the reinforcing ribs 12b, a pin 12a to be inserted into the pin hole 41a of the substrate 41 is provided. As a result, the electrical component 40 can be housed in the case 10 above the power storage element group 30.

FIG. 4 is a perspective view in which a part of the case 10 is cut out. Further, FIG. 5 is an enlarged view of a portion shown in the circle of FIG.

From the inner surface of the second side wall 13, the stepped rib 13a projects in the X direction (inside the case 10). The amount of protrusion of the stepped rib 13a in the X direction is such that it slightly interferes with the pressure equalizing plate 50 when the power storage element group 30 or the like is housed in the case 10. Further, the stepped ribs 13a extend in the Z direction, and a plurality of the stepped ribs 13a are provided side by side in the Y direction. One end of each stepped rib 13a is connected to the bottom wall 11, specifically, one end of the base end portion 13b and the tip end portion 13c are both connected to the bottom wall 11, and the other end is the same height as the reinforcing rib 12b in the case 10. It is terminated so that it becomes.

FIG. 6 is a schematic side view of the stepped rib 13a.

The amount of protrusion of the base end portion 13b is constant from the bottom wall 11 to the upper end in the Z direction, and the amount of protrusion D of the tip end portion 13c from the base end portion 13b gradually decreases as the distance from the bottom wall 11 increases. In the present embodiment, the protrusion amount D is zero at the upper end of the stepped rib 13a.

Preferably, the maximum protrusion amount Dmax of the tip portion 13c is 0.1 mm or more. In the present embodiment, the maximum protrusion position of the tip portion 13c is the connection portion with the bottom wall 11, and the maximum protrusion amount Dmax at that position is, for example, 0.2 mm.

FIG. 7 is a schematic cross-sectional view of the stepped rib 13a along the line VII-VII of FIG. Further, FIG. 8 is a schematic cross-sectional view showing how the stepped rib 13a of FIG. 7 is crushed. That is, FIG. 7 shows a state before the storage element group 30 is housed in the case 10, and FIG. 8 shows a state after the power storage element group 30 is housed in the case 10.

The stepped rib 13a protrudes from the inner surface of the second side wall 13 and has a base end portion 13b having a first width d1, and a second width that protrudes from the top surface S of the base end portion 13b and is narrower than the first width d1. It has a tip 13c with d2. In the present embodiment, in a plan view, the base end portion 13b has a rectangular shape, and the tip end portion 13c has a rectangular shape having a rounded end portion. Even if the stepped rib 13a is pressed by the power storage element group 30 via the pressure equalizing plate 50 from the state shown in FIG. 7 by such a stepped rib 13a, the base end portion 13b for reinforcement is as shown in FIG. The shape of is maintained, and only the tip portion 13c for pressure restraint is crushed.

Preferably, the first width d1 is at least twice as large as the second width d2. In the present embodiment, the first width d1 is about twice as large as the second width d2. Various shapes can be considered as the shape of the stepped rib 13a, but any shape can be used as long as the shape has a step such that the first width d1 is larger than the second width d2. Can be adopted as.

According to the power storage device 1 of the present embodiment, there are the following advantages.

The base end portion 13b of the stepped rib 13a reinforces the second side wall 13 of the case 10, and the tip end portion 13c of the stepped rib 13a pressurizes and restrains the power storage element group 30 in the X direction via the pressure equalizing plate 50. When the power storage element group 30 is housed in the case 10, the stepped rib 13a can be crushed by being pressed by the power storage element group 30 via the pressure equalizing plate 50. As a mode of being crushed, since the tip end portion 13c is thinner than the base end portion 13b, the tip end portion 13b is crushed without being crushed. As a result, even if the size of the power storage element group 30 housed in the case 10 is not constant, the internal volume of the case 10 appropriately changes according to the power storage element group 30 depending on how the tip portion 13c is crushed. Therefore, since the power storage element group 30 is housed in the case 10 without a gap, the power storage element group 30 can be pressure-constrained to the extent that stable battery performance can be ensured without using a restraining member such as a band. Further, since the shape of the base end portion 13b is maintained, the strength of the case 10 can be ensured. Further, since the base end portion 13b for reinforcement and the tip end portion 13c for pressurization restraint are not formed separately but integrally formed, space saving can be realized.

Since the stepped rib 13a is connected to the bottom wall 11, the strength of the case 10 can be improved. Further, when designing the case 10 by resin molding, the mold design becomes easy, that is, the molded case 10 can be easily removed from the mold.

Since the protrusion amount D of the tip portion 13c is smaller toward the upper part of the case 10, a wide space can be secured in the case 10. Since the electrical component 40 is arranged on the upper part of the case 10, a wide space for arranging the electrical component 40 can be secured by the above configuration.

By setting the protrusion amount D of the tip portion 13c to 0.1 mm or more (0.2 mm in this embodiment), the tip portion 13c can be reliably crushed, and these size changes can be dealt with depending on the degree of crushing.

Even if the stepped rib 13a is pressed by the power storage element 31, the shape of the reinforcing base end portion 13b is maintained, and only the tip portion 13c for pressurization restraint can be crushed. Therefore, the strength of the case 10 can be maintained and the power storage element group 30 can be pressure-constrained.

FIG. 9 shows a schematic side view of the stepped rib 13a of the case 10 in the power storage device 1 of the first modification.

As shown in this modification, the tip portion 13c of the stepped rib 13a is not connected to the bottom wall at the lower end, the protrusion amount is zero, and the most in the central portion of the stepped rib 13a in the Z direction. It protrudes, and the amount of protrusion is zero even at the upper end. That is, the tip portion 13c projects in an arch shape toward the inside of the case 10 in the X direction.

As described above, the tip portion 13c does not have to be connected to the bottom wall 11. Furthermore, it is not essential that the proximal end 13b is also connected to the bottom wall. Further, the protruding shape of the tip portion 13c from the base end portion 13b may be any shape other than those shown in FIGS. 6 and 9.

FIG. 10 shows a schematic cross-sectional view of the stepped rib 13a of the case 10 in the power storage device 1 of the second modification.

As shown in this modification, the base end portion 13b of the stepped rib 13a may have a trapezoidal shape that tapers in the X direction (inside of the case 10). As described above, the shape of the base end portion 13b is not particularly limited and may be any shape.

FIG. 11 shows a schematic cross-sectional view of the stepped rib 13a of the case 10 in the power storage device 1 of the third modification.

As shown in this modification, the tip portion 13c of the stepped rib 13a may have a shape sharpened in the X direction (inside of the case 10). As described above, the shape of the tip portion 13c is not particularly limited and may be any shape.

As shown in the second modification and the third modification, any shape can be adopted as the shape of the stepped rib 13a as long as the shape has a step.

Although the specific embodiment of the present invention and the modification thereof have been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. In the present embodiment, the direction orthogonal to the X direction is defined as the Y direction, but the Y direction may be a direction that simply intersects the X direction. That is, the exterior body 5 may have a parallelogram outer shape other than a rectangle in a plan view. Further, the number of steps of the stepped rib 13a is not particularly limited, and may be, for example, three or more steps.

1 Power storage device 5 Exterior 10 Case 11 Bottom wall 12 1st side wall 12a Pin 12b Reinforcing rib 13 2nd side wall 13a Stepped rib 13b Base end 13c Tip 20 Lid 21 Electrode terminal 30 Power storage element group 30a Short side surface 30b Length Side surface 31 Power storage element 31a Short side surface 31b Long side surface 32 Insulation sheet 40 Electrical components 41 Board board 41a Pin hole 50 Pressure equalizing plate

Claims (5)

A group of energy storage elements in which multiple energy storage elements are arranged in an array direction,
An exterior body that accommodates the energy storage element group and has a first side wall that faces parallel to the arrangement direction and a second side wall that faces the direction that intersects the arrangement direction.
A stepped rib having a base end portion protruding from the inner surface of the second side wall and having a first width, and a tip portion protruding from the top surface of the base end portion and having a second width narrower than the first width. A power storage device equipped with. The exterior body further has a bottom wall connected to the first side wall and the second side wall.
The power storage device according to claim 1, wherein both the base end portion and the tip end portion are connected to the bottom wall. The exterior body further has a bottom wall connected to the first side wall and the second side wall.
The power storage device according to claim 1 or 2, wherein the amount of protrusion of the tip portion gradually decreases as the distance from the bottom wall increases. The power storage device according to any one of claims 1 to 3, wherein the maximum protrusion amount of the tip portion is 0.1 mm or more. The power storage device according to any one of claims 1 to 4, wherein the first width is more than twice as large as that of the second width.

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