JP2020113417A - Power storage device - Google Patents

Abstract

To provide a power storage device in which generation of high temperature gas can be suppressed even if the high temperature gas is ejected from a power storage cell, and an increase in an inner pressure in a housing case can be suppressed.SOLUTION: The power storage device comprises: a power storage module including a power storage cell; a housing case 10 that houses the power storage module; and an inner pressure regulator 12 that is provided in the housing case 10 and regulates an inner pressure in the housing case 10. The inner pressure regulator 12 includes: a hollow housing 40; and a separation wall part 41 that divides an inner space in the housing 40 into a first space 50 and a second space 51. The first space 50 is communicated with the inner space of the housing case 10, and the second space 51 is communicated with an external space of the housing case 10. The separation wall part 41 moves in the housing 40 by the inner pressure in the housing case 10.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to a power storage device.

The power storage device includes a housing case and a plurality of power storage cells provided in the housing case. The power storage device may be mounted on the vehicle and provided outside the vehicle such as on the lower surface of the floor panel of the vehicle.

When the power storage device is mounted outside the vehicle, the housing case is hermetically sealed in order to prevent foreign matter from entering the housing case.

In such a power storage device, when an internal short circuit occurs in the power storage cell, the temperature inside the power storage cell becomes high and gas is generated in the power storage cell. When the internal pressure in the storage cell rises and the temperature rises, an exothermic reaction is promoted in the storage cell, and further, the internal pressure in the storage cell rises and gas is generated. As a result, high temperature gas is ejected from the electricity storage cell.

In the electricity storage device described in Japanese Patent Application Laid-Open No. 2008-117756, a pressure operated valve is provided in the housing case, and when high temperature gas is ejected from the electricity storage cell and the internal pressure in the housing case rises, the pressure operated valve Opens. Then, the high temperature gas in the housing case is exhausted to the outside.

JP, 2008-117756, A

In the power storage device described in Japanese Patent Application Laid-Open No. 2008-117756, the pressure actuated valve opens after the high temperature gas is ejected from the power storage cell. When the pressure operated valve opens, fresh air enters from the outside of the housing case. When fresh air is supplied to the electricity storage cell from which the high temperature gas is ejected, the high temperature gas and the air may react with each other and a large amount of the high temperature gas may be generated. Therefore, it is conceivable to seal the housing case except for the pressure operation valve, but when hot gas is ejected from the electricity storage cell, the internal pressure in the housing case may become very high.

The present disclosure has been made in view of the above problems, and an object thereof is to suppress the generation of high-temperature gas even when the high-temperature gas is ejected from the power storage cell, An object is to provide a power storage device that can suppress an increase in internal pressure.

The power storage device according to the present disclosure includes a power storage module including a power storage cell, a housing case that houses the power storage module, and an internal pressure adjuster that is provided in the housing case and adjusts the internal pressure in the housing case. Includes a hollow casing and a partition wall partitioning the internal space of the casing into a first space and a second space, and the first space communicates with the internal space of the housing case. The space communicates with the external space of the housing case, and the partition wall moves inside the housing due to the internal pressure in the housing case.

According to the above power storage device, for example, when high temperature gas is ejected from the power storage cell and the internal pressure in the housing case rises, the partition wall portion moves so that the volume of the first space increases. When the volume of the first space becomes large, it is possible to prevent the internal pressure in the housing case from rising. Further, the second space communicating with the outside and the first space communicating with the inner space of the housing case are partitioned by the partition wall portion, and the air outside the power storage device enters the first space and the housing case. Is suppressed. Therefore, when the internal pressure regulator is driven, external air is suppressed from entering the accommodation case. Therefore, the reaction between the high temperature gas ejected from the power storage cell and the outside air is suppressed.

According to the power storage device of the present disclosure, even if the high temperature gas is ejected from the power storage cell, it is possible to suppress the generation of the high temperature gas and suppress the increase of the internal pressure in the housing case.

FIG. 1 is a schematic diagram schematically showing a vehicle 2 equipped with a power storage device 1 according to the present embodiment. FIG. 3 is an exploded perspective view schematically showing power storage device 1. FIG. 3 is a cross-sectional view showing a power storage device 1. FIG. 3 is a plan view showing a bottom surface of power storage device 1. It is a perspective view which shows the electrical storage cell 16 typically. It is a perspective view which shows the internal pressure regulator 12 typically. It is sectional drawing which shows the internal pressure regulator 12 and the structure of the circumference|surroundings. It is sectional drawing which shows the internal pressure regulator 12A which is a modification of the internal pressure regulator 12. It is a perspective view which shows the elastic member 52 typically.

The power storage device according to the present embodiment will be described with reference to FIGS. 1 to 9. Among the configurations shown in FIGS. 1 to 9, the same or substantially the same configurations are designated by the same reference numerals, and the duplicated description will be omitted. Note that, in the structure shown in the embodiment, a structure corresponding to a structure described in a claim may be described in parentheses together with a structure in the claim.

FIG. 1 is a schematic diagram schematically showing a vehicle 2 equipped with power storage device 1 according to the present embodiment. The vehicle 2 includes a floor panel 3, a front wheel 4, and a rear wheel 5. The floor panel 3 is a metal plate member that forms the bottom surface of the vehicle 2. Power storage device 1 is provided on the lower surface of floor panel 3.

FIG. 2 is an exploded perspective view schematically showing power storage device 1. Power storage device 1 includes a housing case 10, a plurality of power storage modules 11, and an internal pressure adjuster 12. The housing case 10 is filled with an inert gas such as nitrogen.

The housing case 10 includes a lower case 13, an upper case 14, and a seal member 15. The lower case 13 and the upper case 14 are connected to each other by a bolt or the like (not shown).

The lower case 13 is formed so as to open upward. The lower case 13 includes a bottom plate 20, a peripheral wall 21, and a collar portion 22. The peripheral wall 21 is formed so as to extend upward from the outer peripheral edge portion of the bottom plate 20, and is formed in an annular shape along the outer peripheral edge portion of the bottom plate 20.

The collar portion 22 is connected to the upper side of the peripheral wall 21, and is formed so as to project in the horizontal direction from the upper side of the peripheral wall 21. Both the collar portion 22 and the peripheral wall 21 are formed in an annular shape. Plural bolt holes are formed in the collar portion 22 at intervals.

The upper case 14 is formed so as to open downward. The upper case 14 includes a top plate 23, a peripheral wall 24, and a collar portion 25. The peripheral wall 24 includes side walls 26 and 27 and a rear wall 28. The side wall 26 and the side wall 27 are arranged in the width direction W, and the rear wall 28 is arranged on the rear surface of the upper case 14.

The brim portion 25 is formed so as to horizontally project from the opening edge portion of the upper case 14. The collar portion 25 is formed in an annular shape. The collar portion 25 has a plurality of bolt holes formed at intervals.

Here, a bolt (not shown) is inserted into a bolt hole formed in the collar portion 22 and a bolt hole formed in the collar portion 25. The bolt and the nut (not shown) allow the lower case 13 And the upper case 14 is connected to each other.

The seal member 15 is formed in an annular shape, and the seal member 15 is arranged between the collar portion 22 and the collar portion 25. The seal member 15 is, for example, an O-ring. Then, the bolts and nuts connect the lower case 13 and the upper case 14 so that the seal member 15 is brought into close contact with the flange portion 22 and the flange portion 25. As a result, the inside of the housing case 10 is in a sealed state.

Since the housing case 10 is sealed, the inert gas filled in the housing case 10 is suppressed from leaking to the outside of the housing case 10.

FIG. 3 is a cross-sectional view showing power storage device 1, and FIG. 4 is a plan view showing the bottom surface of power storage device 1. The lower case 13 includes a plurality of reinforcing members 30. The reinforcing member 30 is provided on the lower surface of the bottom plate 20. The reinforcing members 30 are provided at intervals in the front-rear direction D. Each reinforcing member 30 is formed so as to extend in the width direction W. In this way, since the plurality of reinforcing members 30 are provided, the rigidity of the lower case 13 is enhanced.

Returning to FIG. 2, power storage device 1 includes a plurality of power storage modules 11. Each power storage module 11 includes power storage cells 16 arranged in the width direction W. Adjacent storage cells 16 are electrically connected in series with each other. Each power storage cell 16 is, for example, a lithium ion battery.

FIG. 5 is a perspective view schematically showing the electricity storage cell 16. The electricity storage cell 16 includes a case 31, an electrode body 32, and an electrolytic solution (not shown). The case 31 is made of aluminum or an aluminum alloy. The electrode body 32 and the electrolytic solution are housed in the case 31. The electrode body 32 includes a positive electrode sheet, a separator, and a negative electrode sheet.

An explosion-proof valve 33 is formed on the upper surface of the case 31. The explosion-proof valve 33 is formed to break and open when the internal pressure in the case 31 exceeds a predetermined pressure.

As shown in FIGS. 2 and 3, the internal pressure regulator 12 is provided on the rear wall 28. FIG. 6 is a perspective view schematically showing the internal pressure adjuster 12, and FIG. 7 is a sectional view showing the configuration of the internal pressure adjuster 12 and its surroundings.

The internal pressure adjuster 12 includes a housing 40 formed in a hollow shape and a partition wall 41 provided in the housing 40. In the example shown in FIG. 5, the case 40 is formed in a hollow columnar shape, and the case 40 is formed of metal or the like, for example.

The housing 40 includes a tubular portion 42 and a closing plate 43. An opening 48 is formed at one end of the tubular portion 42 located on the housing case 10 side, and the other end of the tubular portion 42 is closed by a closing plate 43. A stopper 49 is formed on the inner peripheral surface of the housing 40. The stopper 49 is formed so as to project from the inner peripheral surface of the housing 40.

A through hole 44 is formed in the closing plate 43, and a ventilation film 45 is provided in the through hole 44. The ventilation film 45 is, for example, a waterproof and moisture-permeable material, and GORE-TEX (registered trademark) or the like can be adopted.

The partition wall 41 includes a main body 46 and a seal member 47. The main body 46 is formed in a plate shape and is made of, for example, metal. The seal member 47 is provided on the outer peripheral surface of the main body 46, and the seal member 47 is formed in an annular shape. The seal member 47 is made of resin or the like, and may be an O-ring or the like, for example. The seal member 47 is in close contact with the inner peripheral surface of the housing 40.

The internal space of the housing 40 is partitioned by a partition wall 41 into a pressure adjusting space (first space) 50 and a pressure adjusting space (second space) 51. The pressure regulating space 50 communicates with the internal space inside the housing case 10 through the opening 48. The pressure regulating space 51 communicates with the external space of the power storage device 1 through the ventilation film 45.

In the power storage device 1 configured as described above, for example, when an excessive impact force is applied from the outside, an internal short circuit may occur in any one of the plurality of power storage cells 16.

In FIG. 5, when an internal short circuit occurs in the storage cell 16, the temperature inside the storage cell 16 rises and gas is generated, so that the temperature inside the storage cell 16 and the internal pressure rise. When the internal pressure and temperature in the storage cell 16 rise, the exothermic reaction is promoted in the storage cell 16, and the internal pressure and temperature in the storage cell 16 rapidly increase.

Then, when the internal pressure in the storage cell 16 becomes equal to or higher than a predetermined pressure, the explosion-proof valve 33 breaks. When the explosion-proof valve 33 is broken, the combustible high temperature gas is ejected from the electricity storage cell 16.

Here, since the inside of the housing case 10 is filled with a non-combustible gas such as nitrogen, it is suppressed that the high temperature gas and the air (oxygen) are combined.

On the other hand, when hot gas is ejected from the electricity storage cell 16, the internal pressure in the housing case 10 rises. When the internal pressure in the housing case 10 rises, the pressure in the pressure regulating space 50 also rises in FIGS. 6 and 7, and the partition wall 41 moves toward the closing plate 43. At this time, a part of the air in the pressure regulating space 51 is exhausted to the outside of the power storage device 1 through the ventilation film 45.

By moving the partition wall 41 in this manner, the internal volume of the pressure adjusting space 50 increases. Since the pressure regulating space 50 communicates with the internal space of the housing case 10 through the opening 48, the volume of the pressure regulating space 50 increases, so that the rise of the internal pressure in the housing case 10 can be suppressed.

As described above, since it is possible to suppress the internal pressure in the housing case 10 from rising, it is possible to suppress the rigidity required for the housing case 10 to be low. Thereby, for example, the bottom plate 20 and the peripheral wall 21 of the housing case 10 can be made thin. Moreover, the number of the reinforcing members 30 shown in FIG. 3 can be reduced.

Even if the high temperature gas is ejected from the electricity storage cell 16, the increase in the internal pressure in the housing case 10 is suppressed, so that a large pressure is suppressed from being applied to the seal member 15 and the damage to the seal member 15 is suppressed. ing. With this, it is possible to easily ensure the sealing property of the housing case 10, prevent the inert gas filled in the housing case 10 from leaking to the outside, and at the same time, to prevent foreign matter from entering the housing case 10 from the outside of the power storage device 1. Can be suppressed.

In the power storage device 1 configured as described above, a desiccant or a hygroscopic agent may be arranged in the housing case 10. Since the inside of the housing case 10 is hermetically sealed, when the temperature inside the housing case 10 decreases, water droplets easily condense on the inner surface of the housing case 10, but a desiccant or the like should be placed inside the housing case 10. Therefore, it is possible to suppress the occurrence of dew condensation in the housing case 10.

It should be noted that filling the interior of the housing case 10 with an inert gas is not essential. Even if the storage case 10 is air, the storage case 10 is sealed, so the amount of oxygen in the storage case 10 is limited. As a result, even if the combustible high-temperature gas ejected from the electricity storage cell 16 reacts with oxygen, the reaction is likely to be calmed immediately, and it is possible to prevent the temperature inside the housing case 10 from becoming excessively high. It is possible to prevent the internal pressure in the housing case 10 from rising.

FIG. 8 is a cross-sectional view showing an internal pressure adjuster 12A which is a modified example of the internal pressure adjuster 12. The internal pressure adjuster 12A includes a partition wall 41A. The internal pressure adjuster 12 and the internal pressure adjuster 12A are substantially the same except for the structure of the partition wall 41A.

The partition wall 41A includes a main body 46A and a seal member 47A. The main body 46A is made of resin or the like. The seal member 47A includes elastic members 52 and 53. The elastic members 52, 53 are provided on the peripheral surface of the main body 46A and are formed so as to extend in an annular shape. FIG. 9 is a perspective view schematically showing the elastic member 52. As shown in FIG. 9, the elastic member 52 has a shape like a disc spring, and the elastic member 53 is formed similarly to the elastic member 52.

Also in the internal pressure adjuster 12A configured as described above, the outer peripheral edge portions of the elastic members 52 and 53 are in contact with the inner peripheral surface of the housing 40, and the gas is generated between the pressure adjusting space 50 and the pressure adjusting space 51. Is restricted from being distributed.

Then, the partition wall 41</b>A moves toward the closing plate 43 when the internal pressure in the housing case 10 rises, similarly to the partition wall 41 described above. Therefore, also in the internal pressure adjuster 12A, similarly to the internal pressure adjuster 12 described above, an increase in the internal pressure in the housing case 10 can be suppressed.

The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 power storage device, 2 vehicle, 3 floor panel, 4 front wheels, 5 rear wheels, 10 storage case, 11 storage module, 12, 12A internal pressure regulator, 13 lower case, 14 upper case, 15, 47, 47A seal member, 16 Storage cell, 20 bottom plate, 21, 24 peripheral wall, 22,25 collar part, 23 top plate, 26, 27 side wall, 28 rear wall, 30 reinforcing member, 31 case, 32 electrode body, 33 explosion proof valve, 40 case, 41 , 41A partition wall, 42 cylinder part, 43 closing plate, 44 through hole, 45 breathable film, 46, 46A main body, 48 opening part, 49 stopper, 50, 51 pressure adjusting space, 52, 53 elastic member.

Claims (1)

An electricity storage module including an electricity storage cell;
A housing case for housing the electricity storage module,
An internal pressure adjuster provided in the storage case for adjusting the internal pressure in the storage case,
Equipped with
The internal pressure regulator includes a hollow casing and a partition wall partitioning an internal space in the casing into a first space and a second space,
The first space communicates with the internal space of the housing case,
The second space communicates with the external space of the housing case,
The power storage device in which the partition wall moves in the housing by the internal pressure in the housing case.