JP7754263B2 - Power storage device - Google Patents

Description

This disclosure relates to an electricity storage device.

For example, Japanese Patent Application Laid-Open Publication No. 2020-155367 discloses a battery pack comprising multiple battery modules, a housing case that houses these battery modules, a plate disposed above the multiple battery modules, and multiple support members that support the plate. Each battery module includes multiple cells. The housing case has a lower case that opens upward and an upper case that opens downward. Each support member is disposed on the lower case. Multiple ribs are provided on the inner surface of the upper case. Each rib is provided from the inner surface of the upper case toward the plate. Each rib abuts against the plate. In this battery pack, when a downward load acts on the upper case, the load is transmitted to the lower case via the ribs, plate, and support members.

Japanese Patent Application Laid-Open No. 2020-155367

In the battery pack described in JP 2020-155367 A, it is desirable to be able to protect the storage cells not only from loads applied to the case in the vertical direction, but also from loads applied to the case in a direction perpendicular to the vertical direction.

The objective of this disclosure is to provide an energy storage device that can protect energy storage cells from both loads applied to the case in the vertical direction and loads applied in a direction perpendicular to the vertical direction.

An energy storage device according to one aspect of the present disclosure includes: a plurality of energy storage stacks, each including a plurality of energy storage cells arranged in a line in one direction, and arranged in an orthogonal direction perpendicular to both the one direction and the vertical direction; a case that houses the plurality of energy storage stacks; and a protective structure provided within the case that protects the plurality of energy storage cells from a load input to the case. Each energy storage stack of the plurality of energy storage stacks includes a first unit stack that is arranged on one side in the one direction and includes some of the plurality of energy storage cells; and a second unit stack that is arranged on the other side in the one direction and includes some of the plurality of energy storage cells. The case has a second unit stack including energy storage cells other than those included in the first unit stack, and an intermediate plate arranged between the first unit stack and the second unit stack, and the case has a bottom wall arranged below the plurality of energy storage stacks, a top wall arranged above the plurality of energy storage stacks, and a peripheral wall connecting the peripheral edge of the bottom wall to the peripheral edge of the top wall and surrounding the plurality of energy storage stacks, the length of the protective structure in the vertical direction being greater than the length of the plurality of energy storage cells in the vertical direction, and the protective structure being arranged between a pair of the intermediate plates adjacent to each other in the perpendicular direction.

This disclosure provides an energy storage device that can protect energy storage cells from both loads applied to the case in the vertical direction and loads applied in a direction perpendicular to the vertical direction.

1 is a perspective view schematically illustrating a configuration of an electricity storage device according to an embodiment of the present disclosure. FIG. 2 is a perspective view schematically showing a state before the power storage stack is placed on the lower case. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a plan view schematically showing the positional relationship between a load transmitting member and an intermediate plate.

Embodiments of the present disclosure will be described with reference to the drawings. Note that in the drawings referenced below, identical or equivalent components are designated by the same numbers.

Figure 1 is a perspective view showing a schematic configuration of an energy storage device according to one embodiment of the present disclosure. This energy storage device 1 is mounted, for example, on a vehicle.

As shown in Figures 1 to 3, the energy storage device 1 includes multiple energy storage stacks 100, a case 200, a protective structure 300, a monitoring unit 410, and a wire harness 420.

As shown in FIG. 1, each power storage stack 100 has a plurality of power storage cells 110 arranged in one direction. Examples of the power storage cells 110 include lithium ion batteries. Each power storage cell 110 is formed in a rectangular parallelepiped shape. As shown in FIG. 1, the multiple power storage stacks 100 are arranged in an orthogonal direction that is perpendicular to both the one direction and the vertical direction.

Each storage stack 100 has a first unit stack 101, a second unit stack 102, and an intermediate plate 103.

The first unit stack 101 is arranged on one side in one direction. The first unit stack 101 includes some of the multiple storage cells 110. The first unit stack 101 may include an end plate. The end plate is arranged outside the storage cell 110 arranged outermost in one direction.

The second unit stack 102 is arranged on the other side in one direction. The second unit stack 102 includes, of the multiple storage cells 110, storage cells 110 other than the storage cells 110 included in the first unit stack 101. In this embodiment, the number of storage cells 110 included in the second unit stack 102 is the same as the number of storage cells 110 included in the first unit stack 101. The second unit stack 102 may include end plates arranged outside the storage cells 110 in one direction.

The intermediate plate 103 is disposed between the first unit stack 101 and the second unit stack 102. The intermediate plate 103 is disposed in the center of the power storage stack 100 in one direction. The intermediate plate 103 is made of synthetic resin or the like.

The case 200 houses multiple power storage stacks 100. The case 200 has a lower case 210 and an upper case 220 (see Figure 3). Note that the upper case 220 is not shown in Figures 1 and 2.

The lower case 210 has an upwardly opening shape. The lower case 210 is made of metal, synthetic resin, or the like. The lower case 210 has a bottom wall 212, a lower surrounding wall 214, and a lower flange 216.

The bottom wall 212 is disposed below the multiple power storage stacks 100. As shown in Figures 2 and 3, a raised portion 212a that rises upward is formed in the center of one direction of the bottom wall 212. The top of the raised portion 212a is formed flat. As shown in Figure 3, the intermediate plate 103 is placed on the raised portion 212a.

A cooler (not shown) may be provided below the bottom wall 212 to cool the power storage stack 100 via the bottom wall 212. In this case, a thermally conductive member (such as grease) may be provided between the cooler and the bottom wall 212, or a thermally conductive member may be provided between each power storage stack 100 and the bottom wall 212.

The lower surrounding wall 214 rises from the peripheral edge of the bottom wall 212 and surrounds the lower periphery of the multiple energy storage stacks 100.

The lower flange 216 has a shape that protrudes outward from the upper end of the lower surrounding wall 214.

The upper case 220 has a shape that opens downward. The upper case 220, together with the lower case 210, houses multiple power storage stacks 100. The upper case 220 is made of metal, synthetic resin, or the like. The upper case 220 has a top wall 222, an upper surrounding wall 224, and an upper flange 226.

The top wall 222 is disposed above the multiple power storage stacks 100. The top wall 222 may be formed in a flat plate shape. A gap is formed between the top wall 222 and each power storage stack 100.

The upper surrounding wall 224 extends downward from the peripheral edge of the top wall 222 and surrounds the upper periphery of the multiple power storage stacks 100. The upper surrounding wall 224 forms a peripheral wall together with the lower surrounding wall 214. The peripheral walls 214, 224 connect the peripheral edge of the bottom wall 212 and the peripheral edge of the top wall 222, and surround the periphery of the multiple power storage stacks 100.

The upper flange 226 extends outward from the lower end of the upper surrounding wall 224. The upper flange 226 is fixed to the lower flange 216 with bolts or the like.

The protective structure 300 is provided within the case 200 and protects the multiple energy storage cells 110 from loads input to the case 200. As shown in FIG. 3, the length of the protective structure 300 in the vertical direction is greater than the length of the multiple energy storage cells 110 in the vertical direction. As shown in FIG. 4, the protective structure 300 is disposed between a pair of intermediate plates 103 adjacent to each other in the perpendicular direction. In this embodiment, the protective structure 300 has a cross member 310 and a load transfer member 320. Note that in FIG. 3, the first unit stack 101, the second unit stack 102, and the intermediate plate 103 are indicated by dashed double-dashed lines, while in FIG. 4, the first unit stack 101 and the second unit stack 102 are not shown.

The cross member 310 is disposed on the bottom wall 212. The cross member 310 has a shape that extends in one direction and is connected to the lower surrounding wall 214. In other words, the cross member 310 has the function of reinforcing the lower surrounding wall 214. The cross section of the cross member 310 in a plane perpendicular to the one direction is formed into an upwardly convex shape. The upper surface of the cross member 310 is preferably formed flat. The cross member 310 is disposed between a pair of power storage stacks 100 adjacent to each other in the perpendicular direction. In other words, the cross member 310 separates the pair of power storage stacks 100 adjacent to each other in the perpendicular direction.

The load transfer member 320 is disposed on the cross member 310. The load transfer member 320 transfers a load applied downward to the top wall 222 to the cross member 310. The load transfer member 320 transfers a load applied upward to the bottom wall 212 to the top wall 222. The load transfer member 320 is made of a synthetic resin or the like. As shown in Figure 4, the load transfer member 320 is disposed between a pair of intermediate plates 103 adjacent to each other in the perpendicular direction.

The load transmission member 320 has a first pillar portion 321, a second pillar portion 322, and a connecting portion 323.

The first pillar portion 321 is disposed on the cross member 310. The upper end of the first pillar portion 321 may be in contact with the top wall 222 or may be spaced apart from the top wall 222. The first pillar portion 321 has a first outer surface 321S formed on the outside in one direction. The first outer surface 321S has a shape that gradually separates from the second pillar portion 322 as it approaches the cross member 310. A first connection portion 321a is provided on the first outer surface 321S. The first connection portion 321a has a shape that protrudes outward in one direction from the first outer surface 321S. A through hole is provided in the first connection portion 321a.

The second pillar portion 322 is disposed on the cross member 310. The second pillar portion 322 is disposed at a position spaced apart from the first pillar portion 321 in one direction. The upper end of the second pillar portion 322 may be in contact with the top wall 222 or may be spaced apart from the top wall 222. The second pillar portion 322 has a second outer surface 322S formed on the outside in one direction. The second outer surface 322S has a shape that gradually separates from the first pillar portion 321 as it approaches the cross member 310. A second connection portion 322a is provided on the second outer surface 322S.

The connecting portion 323 connects the first pillar portion 321 and the second pillar portion 322. As shown in Figures 3 and 4, the connecting portion 323 is disposed between a pair of intermediate plates 103 adjacent to each other in the perpendicular direction. The connecting portion 323 may be in contact with the intermediate plate 103 or may be spaced apart from it. As shown in Figure 3, the connecting portion 323 has an opposing surface 323S that faces the top wall 222 with a gap between them.

The connecting portion 323 is provided with a through-hole 323h that passes through the connecting portion 323 in the perpendicular direction. A positioning member 325 may be provided within this through-hole 323h. The positioning member 325 engages with a pair of adjacent power storage stacks 100 in the perpendicular direction across the load transmission member 320, thereby determining the positional relationship between these power storage stacks 100.

The monitoring unit 410 monitors the multiple energy storage cells 110. As shown in FIG. 3, the monitoring unit 410 is positioned on the cross member 310 and adjacent to the load transfer member 320.

The wire harness 420 extends from the monitoring unit 410. As shown in FIG. 3, the wire harness 420 is disposed between the top wall 222 and the opposing surface 323S. The wire harness 420 is fixed to the first connection portion 321a and the second connection portion 322a with bolts or the like. The wire harness 420 may also be fixed to the coupling portion 323.

As described above, in the energy storage device 1 of this embodiment, when a downward load is applied to the top wall 222, the load is transmitted to the bottom wall 212 via the protective structure 300 (first column section 321, second column section 322, and cross member 310). Conversely, when an upward load is applied to the bottom wall 212, the load is transmitted to the top wall 222 via the protective structure 300. This prevents loads applied in the vertical direction to the case 200 from being transmitted to the energy storage cells 110.

Furthermore, when a load is applied in the orthogonal direction to one portion of the peripheral walls 214, 224 in the orthogonal direction, the load is transmitted to the other portion of the peripheral walls 214, 224 in the orthogonal direction via the intermediate plate 103 and the protective structure 300. This prevents the load applied in the orthogonal direction to the peripheral walls from being transmitted to the energy storage cells.

It will be understood by those skilled in the art that the exemplary embodiments described above are specific examples of the following aspects:

The energy storage device in the above embodiment comprises: a plurality of energy storage stacks, each including a plurality of energy storage cells arranged in one direction, and arranged in an orthogonal direction perpendicular to both the one direction and the vertical direction; a case that houses the plurality of energy storage stacks; and a protective structure provided within the case that protects the plurality of energy storage cells from a load input to the case. Each energy storage stack of the plurality of energy storage stacks comprises a first unit stack that is arranged on one side in the one direction and includes some of the plurality of energy storage cells; and a second unit stack that is arranged on the other side in the one direction and includes the front of the plurality of energy storage cells. The case has a second unit stack including energy storage cells other than those included in the first unit stack, and an intermediate plate arranged between the first unit stack and the second unit stack, and the case has a bottom wall arranged below the plurality of energy storage stacks, a top wall arranged above the plurality of energy storage stacks, and a peripheral wall connecting the peripheral edge of the bottom wall to the peripheral edge of the top wall and surrounding the plurality of energy storage stacks, the length of the protective structure in the vertical direction being greater than the length of the plurality of energy storage cells in the vertical direction, and the protective structure being arranged between a pair of the intermediate plates adjacent to each other in the perpendicular direction.

In this energy storage device, when a downward load is applied to the top wall, the load is transmitted to the bottom wall via the protective structure, and when an upward load is applied to the bottom wall, the load is transmitted to the top wall via the protective structure, thereby preventing loads applied in the vertical direction to the case from being transmitted to the energy storage cells. Furthermore, when a load is applied in the perpendicular direction to one side of the peripheral wall in the perpendicular direction, the load is transmitted to the other side of the peripheral wall in the perpendicular direction via the intermediate plate and the protective structure, preventing loads applied in the perpendicular direction to the peripheral wall from being transmitted to the energy storage cells.

The protective structure may also include a cross member that is disposed on the bottom wall and between a pair of adjacent battery stacks in the perpendicular direction, has a shape extending in one direction, and is connected to the peripheral wall, and a load transfer member that is disposed on the cross member. It is preferable that the load transfer member be disposed between a pair of adjacent intermediate plates in the perpendicular direction.

In this configuration, the cross member reinforces the peripheral wall, and the load transfer member transfers the perpendicular load to the intermediate plate.

The load transmission member may also have a first pillar portion, a second pillar portion disposed at a position spaced apart from the first pillar portion in the one direction, and a connecting portion connecting the first pillar portion and the second pillar portion. In this case, it is preferable that the connecting portion be disposed between a pair of the intermediate plates adjacent to each other in the orthogonal direction.

In this configuration, the first and second pillars can transmit vertical loads at positions spaced apart in one direction. Furthermore, because the first and second pillars are connected by a connecting part, handling of the load-transmitting member is easier than when the first and second pillars are made of separate members.

Furthermore, the first pillar portion may have a first outer surface formed on the outside in the one direction, and the second pillar portion may have a second outer surface formed on the outside in the one direction. It is preferable that the first outer surface has a shape that gradually separates from the second pillar portion as it approaches the cross member, and that the second outer surface has a shape that gradually separates from the first pillar portion as it approaches the cross member.

In this embodiment, the resistance to a load input downward to the top wall is particularly increased.
The energy storage device may further include a monitoring unit that monitors the plurality of energy storage cells, and a wire harness extending from the monitoring unit. In this case, it is preferable that the connecting portion has an opposing surface that faces the top wall with a gap therebetween, and the wire harness is disposed between the top wall and the opposing surface.

The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is indicated by the claims, not by the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims.

1 Energy storage device, 100 Energy storage stack, 101 First unit stack, 102 Second unit stack, 103 Intermediate plate, 110 Energy storage cell, 200 Case, 210 Lower case, 212 Bottom wall, 212a Raised portion, 214 Lower surrounding wall, 216 Lower flange, 220 Upper case, 222 Top wall, 224 Upper surrounding wall, 226 Upper flange, 300 Protective structure, 310 Cross member, 320 Load transmission member, 321 First pillar portion, 321S First outer surface, 322 Second pillar portion, 322S Second outer surface, 323 Connecting portion, 323S Opposing surface, 410 Monitoring unit, 420 Wire harness.

Claims (3)

a plurality of power storage stacks each including a plurality of power storage cells arranged to be aligned in one direction and arranged to be aligned in an orthogonal direction that is orthogonal to both the one direction and the vertical direction;
a case that houses the plurality of power storage stacks;
a cross member provided in the case and disposed between a pair of the power storage stacks adjacent to each other in the orthogonal direction,
Each of the plurality of power storage stacks includes:
a first unit stack disposed on one side in the one direction and including some of the plurality of storage cells;
a second unit stack that is disposed on the other side in the one direction and includes, among the plurality of power storage cells, power storage cells other than the power storage cells included in the first unit stack;
an intermediate plate disposed between the first unit stack and the second unit stack,
The case is
a bottom wall disposed below the plurality of power storage stacks;
a top wall disposed above the plurality of power storage stacks;
a peripheral wall disposed to connect a peripheral edge portion of the bottom wall and a peripheral edge portion of the top wall ,
an interposition portion provided on the cross member and disposed between a pair of the intermediate plates adjacent to each other in the perpendicular direction;
a first protruding portion provided on the cross member, disposed on one side of the interposed portion in the one direction, and protruding upward from upper surfaces of the plurality of energy storage cells;
a second protruding portion that is provided on the cross member, is positioned on the other side of the interposition portion in the one direction, and protrudes upward from upper surfaces of the plurality of energy storage cells,
The interposition portion has a through hole that connects a space on one side of the interposition portion to a space on the other side in the orthogonal direction. The power storage device according to claim 1 , further comprising a conductive member arranged above the cross member on one side in the one direction of the first protrusion. The power storage device according to claim 2 , further comprising a monitoring unit connected to the plurality of power storage cells using the conductive member.