JP2023059480A - power storage device - Google Patents

Abstract

To provide a power storage device which can suppress, when gas is exhausted from a power storage cell, damage to an upper case due to heat and temperature increase of the other power storage cells.SOLUTION: A power storage device 100 comprises: a power storage stack 1 which includes a plurality of power storage cells 10 having exhaust valves 12 on top faces 11a thereof respectively; an upper case 21 which covers the power storage stack 1 from the upper side; and a first heat-resistant sheet 31 and a second heat-resistant sheet 32 which have heat resistance property against the exhaust gas exhausted from the exhaust valve 12 and are arranged between the upper case 21 and the power storage stack 1. A plurality of holes 31a are arranged at positions that vertically overlap with the respective exhaust valves 12 in the first heat-resistant sheet 31. The second heat-resistant sheet 32 is arranged above the first heat-resistant sheet 31 to cover the plurality of holes 31a.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a power storage device mounted on a vehicle.

As a conventional power storage device, Japanese Unexamined Patent Application Publication No. 2016-012490 (Patent Document 1) discloses a monitoring board on which a detection unit that detects the state of a battery module is mounted, and a plurality of power storage cells that constitute the power storage module. Disclosed is a heat-resistant member disposed therebetween. The heat-resistant member is arranged so as to face the open valve (exhaust valve) provided in each storage cell. Therefore, when an abnormality occurs in the storage cell and high-temperature gas is discharged from an open valve (exhaust valve) provided in the storage cell, the high-temperature gas can be prevented from directly hitting the monitoring substrate. A monitoring board can be protected.

JP 2016-012490 A

However, in the power storage device disclosed in Patent Document 1, the heat-resistant member causes the high-temperature gas to rebound toward the power storage cells, and the rebounded high-temperature gas increases the temperature of other power storage cells.

Further, in the power storage device, a safety valve for discharging gas discharged from the power storage cell to the outside may be provided in the housing case that houses the power storage module. In such a configuration, there is a case where the monitoring board is not arranged above the power storage module, or there is a part where the monitoring board is not arranged above the power storage module. In this case, if there is no countermeasure, the high-temperature gas discharged from the storage cell may directly blow against the upper case, resulting in thermal damage to the upper case.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to suppress damage to the upper case due to heat when gas is discharged from a storage cell, and to prevent other storage cells from being damaged. An object of the present invention is to provide a power storage device capable of suppressing an increase in the temperature of the battery.

A power storage device according to the present disclosure includes a power storage stack including a plurality of power storage cells each having an exhaust valve provided on the upper surface thereof, an upper case covering the power storage stack from above, and an exhaust gas discharged from the exhaust valve. A first heat-resistant sheet and a second heat-resistant sheet having heat resistance are provided between the upper case and the power storage stack. The first heat-resistant sheet is provided with a plurality of holes at positions overlapping the respective exhaust valves in the vertical direction. The second heat-resistant sheet is arranged above the first heat-resistant sheet so as to cover the plurality of holes.

According to the above configuration, by arranging the second heat-resistant sheet above the first heat-resistant sheet provided with the hole at the position corresponding to the exhaust valve, the gas discharged from the exhaust valve passes through the hole. , can be blocked by the second heat-resistant sheet. As a result, it is possible to prevent the upper case from being damaged by the gas blowing directly against the upper case. In addition, since the first heat-resistant sheet is arranged below the second heat-resistant sheet, the gas blocked by the second heat-resistant sheet is prevented from coming into contact with other non-heat-generating storage cells. It is possible to suppress an increase in the temperature of the storage cell.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a power storage device capable of suppressing temperature rise of other power storage cells while suppressing damage to the upper case due to heat when gas is discharged from the power storage cells.

1 is a schematic cross-sectional view of a power storage device according to an embodiment; FIG. FIG. 2 is a plan view of the power storage stack, the first heat-resistant sheet, and the second heat-resistant sheet viewed from above in the power storage device according to the embodiment; FIG. 4 is a diagram schematically showing a state in which gas is discharged from a storage cell in the power storage device according to the embodiment; FIG. 3 is a schematic cross-sectional view of a power storage device according to a comparative embodiment; FIG. 4 is a diagram schematically showing a state in which gas is discharged from a storage cell in a power storage device according to a comparative embodiment;

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

(Embodiment)
FIG. 1 is a schematic cross-sectional view of a power storage device according to an embodiment. FIG. 2 is a top plan view of the power storage stack, the first heat-resistant sheet, and the second heat-resistant sheet in the power storage device according to the embodiment. A power storage device 100 according to an embodiment will be described with reference to FIGS. 1 and 2. FIG.

Power storage device 100 according to the embodiment is mounted in a hybrid vehicle that can run using power of at least one of a motor and an engine, or an electric vehicle that runs with driving force obtained from electrical energy.

As shown in FIGS. 1 and 2 , power storage device 100 includes power storage stack 1 , housing case 20 , first heat-resistant sheet 31 , and second heat-resistant sheet 32 .

The energy storage stack 1 includes multiple energy storage cells 10 and a pair of end plates 15 . A plurality of storage cells 10 are arranged in a predetermined arrangement direction. The pair of end plates 15 are arranged at both ends of the electricity storage stack 1 in the arrangement direction. The pair of end plates 15 hold the plurality of storage cells 10 together with a binding member (not shown) while sandwiching the plurality of storage cells 10 . A spacer (not shown) is arranged in the gap between each of the plurality of storage cells 10 .

The storage cell 10 includes an exterior body 11 , an exhaust valve 12 , a positive terminal 13 and a negative terminal 14 . The exterior body 11 accommodates a battery element inside. An exhaust valve 12 is provided on the exterior body 11 . The exhaust valve 12 is provided on the upper surface 11 a of the exterior body 11 . The upper surface 11 a corresponds to the upper surface of the storage cell 10 .

Exhaust valve 12 is provided, for example, between positive terminal 13 and negative terminal 14 . The exhaust valve 12 exhausts the gas from the inside of the exterior body 11 to the outside of the exterior body 11 when the pressure inside the exterior body 11 exceeds a predetermined value due to the gas generated in the exterior body 11 due to the heat generation of the electric storage cell 10 . do.

The plurality of storage cells 10 are arranged in the arrangement direction while being inverted one by one so that the positive terminals 13 and the negative terminals 14 are alternately arranged. The plurality of storage cells 10 are connected in series by electrically connecting the positive terminals 13 and the negative terminals 14 that are adjacent to each other in the arrangement direction alternately at both ends in the width direction of the storage cells 10 .

Storage cell 10 is, for example, a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. Storage cell 10 has, for example, a rectangular shape. The secondary battery may use a liquid electrolyte or may use a solid electrolyte.

Storage case 20 accommodates power storage stack 1 , first heat-resistant sheet 31 , and second heat-resistant sheet 32 therein. The housing case 20 has an upper case 21 and a lower case 22 .

The upper case 21 has a substantially box-like shape that opens downward. Upper case 21 is arranged to cover power storage stack 1 from above. The upper case 21 has a ceiling portion 211 , a peripheral wall portion 212 and a flange portion 213 .

Ceiling portion 211 is arranged to face the upper surface of power storage stack 1 . A safety valve 23 is provided on the ceiling portion 211 . The safety valve 23 discharges gas such as gas from inside the housing case 20 to the outside of the housing case 20 when the pressure inside the housing case 20 exceeds a predetermined level.

The peripheral wall portion 212 is provided to extend downward from the peripheral edge of the ceiling portion 211 . The collar portion 213 is provided so as to protrude outward from the lower end of the peripheral wall portion 212 .

The lower case 22 has a generally box-like shape that is open upward. Lower case 22 is arranged to cover power storage stack 1 from below. Lower case 22 has a bottom portion 221 , a peripheral wall portion 222 and a flange portion 223 .

Bottom portion 221 is arranged to face the lower surface of power storage stack 1 . The peripheral wall portion 222 is provided to extend upward from the peripheral edge of the bottom portion 221 . The collar portion 223 is provided so as to protrude outward from the upper end of the peripheral wall portion 222 .

The flange portion 213 of the upper case 21 and the flange portion 223 of the lower case 22 are fastened together with a sealing member (not shown) sandwiched therebetween. As a result, the inside of the storage case 20 is maintained airtight or liquid-tight.

The first heat-resistant sheet 31 and the second heat-resistant sheet 32 have heat resistance against high-temperature gas discharged from the exhaust valve 12 . First heat-resistant sheet 31 and second heat-resistant sheet 32 are arranged between upper case 21 and power storage stack 1 .

The first heat-resistant sheet 31 is arranged above the power storage stack 1 . The first heat-resistant sheet 31 has a shape that spreads in the planar direction. The first heat-resistant sheet 31 is arranged so as to face the upper surface 11 a of each of the plurality of storage cells 10 . The first heat-resistant sheet 31 is provided with a plurality of holes 31a at positions overlapping the respective exhaust valves 12 in the vertical direction. The hole portion 31 a is provided so as to be substantially the same size as the exhaust valve 12 or larger than the exhaust valve 12 .

The second heat-resistant sheet 32 has a shape that spreads in the planar direction. The second heat-resistant sheet 32 is arranged above the first heat-resistant sheet 31 so as to cover the plurality of holes 31a. The second heat-resistant sheet 32 may have approximately the same size as the first heat-resistant sheet 31 .

The first heat-resistant sheet 31 and the second heat-resistant sheet 32 are, for example, sheet members mainly made of magnesium silicate (containing about 75% to 85% by weight of magnesium silicate), or sheets mainly made of silica. You may be comprised by the member. Also, the first heat-resistant sheet 31 and the second heat-resistant sheet 32 may be made of a resin member, a mica plate, or the like. The first heat-resistant sheet 31 and the second heat-resistant sheet 32 have flame retardancy equivalent to or higher than the flame retardancy UL94HB standard. The second heat-resistant sheet 32 is provided so as to be pushed upward by the gas discharged from the exhaust valve 12 .

FIG. 3 is a diagram schematically showing how gas is discharged from a storage cell in the power storage device according to the embodiment.

As shown in FIG. 3, when a predetermined storage cell 10 among the plurality of storage cells 10 generates heat and high-temperature gas G is discharged from the exhaust valve 12 of the predetermined storage cell 10, the gas G is It blows against the second heat-resistant sheet 32 through a hole 31 a provided at a position corresponding to the exhaust valve 12 . Thereby, the gas G is blocked by the second heat-resistant sheet 32 . As a result, it is possible to prevent the gas G from directly blowing against the upper case 21 and the upper case 21 from being damaged by heat.

In addition, the second heat-resistant sheet 32 is pushed upward away from the first heat-resistant sheet 31 by the gas G blowing against the second heat-resistant sheet 32 . As a result, the gas G passes between the first heat-resistant sheet 31 and the second heat-resistant sheet 32 and is discharged out of the storage case 20 through the safety valve 23 as indicated by an arrow AR1 in FIG. At this time, since the first heat-resistant sheet 31 is arranged between the second heat-resistant sheet 32 and the power storage stack 1, the gas G blocked by the second heat-resistant sheet 32 is transferred to other power storage cells that do not generate heat. 10 can be suppressed. Thereby, it is possible to suppress the temperature rise of the other storage cells 10 .

As described above, in the power storage device 100 according to the embodiment, when the gas G is discharged from the power storage cell 10, damage to the upper case 21 due to heat is suppressed, and the temperature of the other power storage cells 10 increases. increase can be suppressed.

(form of comparison)
FIG. 4 is a schematic cross-sectional view of a power storage device according to a comparative example. A power storage device 100X according to a comparative example will be described with reference to FIG.

As shown in FIG. 4 , power storage device 100X according to the comparative example is different from power storage device 100 according to the embodiment in that the second heat-resistant sheet is not provided and the structure of first heat-resistant sheet 31X is different. is different. Other configurations are substantially the same.

Unlike the first heat-resistant sheet 31 according to the embodiment, the first heat-resistant sheet 31X does not have a plurality of holes 31a. The first heat-resistant sheet 31X is arranged to cover the power storage stack 1 from above. The first heat-resistant sheet 31X is arranged so as to face the plurality of exhaust valves 12 .

FIG. 5 is a diagram schematically showing a state in which gas is discharged from a storage cell in a power storage device according to a comparative embodiment.

As shown in FIG. 5, when the gas G is discharged from the predetermined storage cell 10, the first heat-resistant sheet 31X is not provided with holes, so the gas G is blown into the first heat-resistant sheet 31X. Hit. Thereby, the gas G is blocked by the first heat-resistant sheet 31X. Therefore, it is possible to prevent the upper case 21 from being damaged by the heat caused by the gas G blowing directly against the upper case 21 .

On the other hand, the gas G passes between the first heat-resistant sheet 31X and the electricity storage stack 1 and is discharged out of the storage case 20 through the safety valve 23, as indicated by an arrow AR2 in FIG. At this time, the gas G comes into contact with other storage cells 10, and the temperature of the other storage cells 10 rises. As described above, in the power storage device 100 according to the comparative embodiment, damage to the upper case 21 can be suppressed, but the temperature of the other power storage cells 10 increases.

As described above, the embodiments disclosed this time are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the scope of claims, and includes all modifications within the meaning and scope of equivalence to the scope of claims.

1 storage stack 10 storage cell 11 exterior body 11a upper surface 12 exhaust valve 13 positive electrode terminal 14 negative electrode terminal 15 end plate 20 housing case 21 upper case 22 lower case 23 safety valve 31, 31X first Heat-resistant sheet, 31a hole, 32 second heat-resistant sheet, 100, 100X power storage device, 211 ceiling, 212 peripheral wall, 213 flange, 221 bottom, 222 peripheral wall, 223 flange.

Claims (1)

an electricity storage stack including a plurality of electricity storage cells each provided with an exhaust valve on the top surface thereof;
an upper case covering the power storage stack from above;
a first heat-resistant sheet and a second heat-resistant sheet having heat resistance against the exhaust gas discharged from the exhaust valve and disposed between the upper case and the electricity storage stack;
The first heat-resistant sheet is provided with a plurality of holes at positions overlapping each of the exhaust valves in the vertical direction,
The power storage device, wherein the second heat-resistant sheet is arranged above the first heat-resistant sheet so as to cover the plurality of holes.

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