Battery pack

Abstract

This battery pack has a battery cell housed in a battery case. The battery case is provided with an open space that connects with the outside of the battery case at least at two different locations, and a closed space that is blocked from the outside of the battery case and from the open space. The battery cell is installed in the open space and has a pressure release valve that allows the inside of the battery cell and the closed space to connect with each other.

Description

Battery pack

[0001] The present disclosure relates to a battery pack.

[0002] Patent Document 1 discloses a battery pack including a plurality of battery cells, a battery case that forms a battery storage chamber in which the plurality of battery cells are stored, a cooling air passage that is separated from the battery storage chamber by a partition that is part of the battery case, an air blower that blows air into the cooling air passage, and a gas exhaust passage that is provided to connect the battery storage chamber to the outside of the vehicle.

[0003] Japanese Patent Application Laid-Open No. 2016-197551

[0004] When the battery pack disclosed in Patent Document 1 is installed inside a vehicle, the gas exhaust passage needs to be extended to the outside of the vehicle, which requires costs for parts, assembly, etc. Furthermore, because the gas exhaust passage connects the battery chamber to the outside of the vehicle, there is a risk of foreign objects such as sand and insects entering the passage.

[0005] In view of the above circumstances, at least one embodiment of the present invention aims to provide a battery pack that can prevent smoke gas from leaking outside the battery pack even if smoke gas is generated inside a battery cell due to an abnormality in the battery cell.

[0006] (1) A driving battery pack for an electric vehicle according to at least one embodiment of the present invention is a battery pack in which battery cells are housed within a battery case, the battery case being provided with an open space that communicates with the outside of the battery case at at least two different locations, and a closed space that is isolated from the outside of the battery case and the open space, the battery cells being installed in the open space and having pressure release valves that communicate between the inside of the battery cells and the closed space.

[0007] According to the configuration (1) above, when smoke gas is generated inside a battery cell due to an abnormality in the battery cell, the pressure inside the battery cell increases and the pressure release valve opens, thereby connecting the inside of the battery cell to the closed space and allowing the smoke gas generated inside the battery cell to flow into the closed space, thereby preventing the smoke gas from leaking outside the battery pack.

[0008] (2) In some embodiments, in the configuration of (1) above, the volume of the closed space is greater than the amount of smoke gas generated inside the battery cell.

[0009] According to the above configuration (2), the smoke gas generated inside the battery cell can be confined in a closed space.

[0010] (3) In some embodiments, in the configuration described in (1) or (2) above, the closed space is provided at a position that is on both outer sides in the width direction of the electric vehicle when the battery pack is installed in the passenger compartment of the electric vehicle.

[0011] According to the configuration of (3) above, when the electric vehicle is hit in a side collision, the closed space collapses, and the battery pack can absorb the impact of the side collision.

[0012] (4) In some embodiments, in the configuration of (1) or (2) above, the closed space is provided at a position that is on the front side of the electric vehicle in the fore-and-aft direction when the battery pack is installed in the passenger compartment of the electric vehicle.

[0013] According to the configuration of (4) above, when the electric vehicle is hit from the front, the closed space collapses, and the battery pack can absorb the impact of the head-on collision.

[0014] (5) In some embodiments, in the configuration of (1) or (2) above, the closed space is provided at a position that is rearward in the fore-and-aft direction of the electric vehicle when the battery pack is installed in the passenger compartment of the electric vehicle.

[0015] According to the configuration of (5) above, when the electric vehicle is hit from behind, the closed space collapses, and the battery pack can absorb the impact of the collision.

[0016] (6) In some embodiments, in the configuration of (1) or (2) above, the closed space is provided at a position that is on the upper side in the height direction of the electric vehicle when the battery pack is installed in the passenger compartment of the electric vehicle.

[0017] According to the above configuration (6), gas generated inside the battery cell due to an abnormality in the battery cell can be stored in the closed space provided above in the height direction of the electric vehicle.

[0018] (7) In some embodiments, in the configuration (1) or (2) above, the closed spaces are provided at positions that are in front and rear of the electric vehicle in a longitudinal direction when the battery pack is installed in the passenger compartment of the electric vehicle, and at a position that is in communication with the rear position and is on the upper side in a height direction of the electric vehicle, and the closed space provided at the front position is provided with a contactor that cuts off the flow of electricity between the outside and the inside of the battery pack, while the closed space provided at the rear position is provided with a thermal fuse that cuts off the flow of electricity to the battery cells.

[0019] According to the configuration (7) above, smoke gas generated inside a battery cell due to an abnormality in the battery cell and flowing into the closed space through the pressure release valve mainly passes through the closed space located at the rear of the electric vehicle in the longitudinal direction and flows into another closed space located at the upper side in the height direction of the electric vehicle, allowing the contactor to operate normally and the thermal fuse to blow quickly.

[0020] According to at least one embodiment of the present invention, even if smoke gas is generated inside a battery cell due to an abnormality in the battery cell, leakage of the smoke gas to the outside of the battery pack can be suppressed.

[0021] Fig. 2 is a diagram showing a schematic view of a battery pack according to an embodiment. Fig. 3 is a cross-sectional view of the battery pack shown in Fig. 1 taken along line II-II. Fig. 4 is a cross-sectional view of the battery pack shown in Fig. 1 taken along line III-III. Fig. 5 is a diagram showing a battery pack according to an embodiment, a blower fan installed in the battery pack, and a duct connected to the blower fan.

[0022] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0023] [Electric vehicle equipped with battery pack] The battery pack according to the embodiment is equipped in an electric vehicle such as an electric vehicle (EV), a hybrid vehicle (HV), or a fuel cell vehicle (FCV). Hybrid vehicles include plug-in hybrid vehicles (PHV, PHEV). Plug-in hybrid vehicles can be charged (external charging) from an external device (e.g., a quick charger) while parked, but may also be able to supply power (external power supply) to an external device (e.g., a general household) while parked.

[0024] 1 to 3 , the battery pack 1 according to the embodiment is a battery pack in which battery cells 3 are housed in a battery case 2, and is installed in the passenger compartment of an electric vehicle. The battery pack 1 according to the embodiment is installed under the driver's seat and passenger seat along the vehicle width direction, but is not limited to this, and may also be installed under the rear seat or in the luggage compartment, for example.

[0025] [Configuration of Battery Pack] The battery case 2 according to the embodiment is configured with, but is not limited to, a tray 21 with an open top and a cover 22 that closes the opening of the tray 21. The battery case 2 according to the embodiment is provided with an open space 4 that communicates with the outside of the battery case 2 at at least two locations, and a closed space 5 that is isolated from the outside of the battery case 2 and the open space 4.

[0026] At least two locations are air inlets 23, 23 and an exhaust outlet 24 provided on the top surface of the battery case 2 (cover 22). The open space 4 is provided between the air inlet 23 and the exhaust outlet 24 and communicates with the outside of the battery case 2 via the air inlet 23 and the exhaust outlet 24. The battery case 2 according to the embodiment is provided with a pair (two) air inlets 23, 23 and one exhaust outlet 24, and the open space 4 is provided between the pair of air inlets 23, 23 and the one exhaust outlet 24, but this is not limited thereto. As described above, when the battery pack 1 is installed under the driver's seat and the passenger seat, the pair of air inlets 23, 23 are provided on the outer side of the driver's seat in the vehicle width direction and the outer side of the passenger seat in the vehicle width direction, and one exhaust outlet 24 is provided between the driver's seat and the passenger seat, but this is not limited thereto. The closed space 5 is provided adjacent to the open space 4, but this is not limited thereto.

[0027] A battery cell 3 according to the embodiment is installed in the open space 4 and has a pressure release valve 31 that connects the interior of the battery cell 3 to the closed space 5. According to the embodiment, there are a plurality (a large number) of battery cells 3, and the plurality of battery cells 3 are connected in series and installed in the open space 4. All of the battery cells 3 installed in the open space 4 are grouped into several groups, and the plurality of battery cells 3 included in a group constitute one battery module 32. All of the battery cells 3 installed in the open space 4 are arranged such that the surfaces on which the pressure release valves 31 are provided define the closed space 5, and the pressure release valves 31 of all of the battery cells 3 installed in the open space 4 connect the interior of the battery cell 3 to the closed space 5.

[0028] The open space 4 according to this embodiment includes a storage space 41 in which a battery module 32 (battery cell 3) is installed, an air intake path 42 connecting each of the pair of air intake ports 23, 23 to the storage space 41, and an exhaust path 43 connecting the storage space 41 to the exhaust port 24. The air intake path 42 communicates with each of the air intake ports 23, 23 to a lower region of the battery module 32 installed in the storage space 41, and when the battery pack 1 is installed in the vehicle width direction under the driver's seat and passenger seat of an electric vehicle, air within the vehicle cabin is supplied to the battery module 32 from the air intake ports 23, 23. The exhaust path 43 communicates with an upper region of the battery module 32 installed in the storage space 41 to the exhaust port 24, and when the battery pack 1 is installed in the vehicle width direction under the driver's seat and passenger seat of an electric vehicle, the air supplied to the battery module 32 is discharged into the vehicle cabin through the exhaust port 24. The air intake side path 42 is defined by the inner wall surface of the battery case 2 and the outer surface of the battery module 32 (battery cell 3), and the exhaust side path 43 is defined by the duct 25 connecting the storage space 41 and the exhaust port 24, but is not limited to this.

[0029] In the battery pack 1 according to the embodiment, a plurality of battery modules 32 are installed in the battery case 2, and the air intake side path 42 branches from a pair of air intake ports 23, 23 toward each of the plurality of battery modules 32, and the air exhaust side path 43 converges from each of the plurality of battery modules 32 toward one air exhaust port 24, but this is not limited to this.

[0030] The capacity of the closed space 5 according to the embodiment is larger than the amount of smoke gas generated inside the battery cell 3. The amount of smoke gas generated inside the battery cell 3 is the amount of gas under standard conditions, and it is preferable that the capacity of the closed space 5 is sufficiently larger than the amount of smoke gas generated inside the battery cell 3.

[0031] 2 , a closed space 51 according to this embodiment is provided between battery modules 32. The gap between the battery module 32 and the battery case 2 (tray 21), which defines this closed space 51, is sealed with a foam seal 26 to maintain airtightness. A pressure release valve 31 is provided on the side of the battery module 32 (battery cell 3) which defines this closed space 51, and the pressure release valve 31 connects this closed space 51 to the inside of the battery cell 3.

[0032] The closed spaces 52 according to the embodiment are provided at positions on both outer sides in the width direction of the electric vehicle when the battery pack 1 is installed in the passenger compartment of the electric vehicle, under the driver's seat and passenger seat. The closed spaces 52 are provided on both sides of the storage space 41, below the air intake ports 23, 23, so as to surround the air intake path 42. The gap between the battery module 32 and the battery case 2 (tray 21), which defines the closed space 52, is sealed with a foam seal 27, and the closed space 52 communicates with the closed space 51 provided between the battery modules 32.

[0033] 3 , the closed space 53 according to this embodiment is provided at a position on the front side in the longitudinal direction of the electric vehicle when the battery pack 1 is installed in the passenger compartment of the electric vehicle, under the driver's seat and passenger seat. The space between the battery module 32 and the battery case 2 (tray 21), which defines the closed space 53, is sealed with a foam seal 28, and communicates with the closed space 51 provided between the battery modules 32.

[0034] The closed space 54 according to the embodiment is provided at a position on the rear side in the longitudinal direction of the electric vehicle when the battery pack 1 is installed in the passenger compartment of the electric vehicle, under the driver's seat and passenger seat. The space between the battery module 32 and the battery case 2 (tray 21), which defines the closed space 54, is sealed with a foam seal 29, and communicates with the closed space 51 provided between the battery modules 32.

[0035] 3 , the closed space 55 according to this embodiment is provided at a position on the upper side in the height direction of the electric vehicle, which communicates with the closed space 54 provided at a position on the rear side in the longitudinal direction of the electric vehicle when the battery pack 1 is installed in the vehicle cabin. The closed space 53 provided at the front side is provided with a contactor 34 that cuts off the flow of electricity between the outside and the inside of the battery pack 1, while the closed space 54 provided at the rear side is provided with a thermal fuse 35 that cuts off the flow of electricity to the battery cells 3.

[0036] [Operation of Battery Pack] The battery pack 1 according to the first embodiment is installed in the passenger compartment of an electric vehicle, below the driver's seat and passenger seat, along the vehicle width direction, and as shown in Fig. 4, a blower fan 6 is installed above the battery pack 1. The intake port of the blower fan 6 is connected to the exhaust port 24 of the battery pack 1, and a duct 7 is connected to the outlet of the blower fan 6. The duct 7 extends from the outlet of the blower fan 6 to a position facing the dash panel.

[0037] When the blower fan 6 is operated, air inside the battery pack 1 passes through the exhaust port 24, is sucked in through the inlet of the blower fan 6, and is discharged from the outlet of the blower fan 6. As a result, air inside the vehicle cabin is supplied into the battery pack 1 through the air inlets 23, 23.

[0038] Air supplied to the interior of the battery pack 1 from the air inlets 23, 23 passes through the air inlet path 42 and is supplied to the storage space 41, where it cools the battery modules 32 (battery cells 3). After cooling the battery modules 32, the air passes through the exhaust path 43 and is supplied to the exhaust port 24. Meanwhile, air discharged from the outlet passes through the duct 7 and is exhausted into the vehicle interior at a position opposite the dash panel.

[0039] When an abnormality in a battery cell 3 causes smoke gas to be generated inside the battery cell 3, the pressure inside the battery cell 3 increases and the pressure release valve 31 opens. As a result, the pressure release valve 31 connects the inside of the battery cell 3 to the closed space 51 provided between the battery modules 32, and the smoke gas is discharged into the closed space 51 provided between the battery modules 32. The smoke gas discharged into this closed space 51 mainly passes through closed space 54 provided at a position on the rear side in the fore-and-aft direction of the electric vehicle, and is accumulated in closed space 55 provided at a position on the upper side in the height direction of the electric vehicle.

[0040] [Effects of the Battery Pack] In the battery pack 1 according to the embodiment, when smoke gas is generated inside a battery cell 3 due to an abnormality in the battery cell 3, the pressure inside the battery cell 3 increases and the pressure release valve opens. This connects the inside of the battery cell 3 with the closed space 5, and the smoke gas generated inside the battery cell 3 flows into the closed space 5, thereby preventing the smoke gas from leaking outside the battery pack.

[0041] Furthermore, since the capacity of the closed space 5 is greater than the amount of smoke gas generated inside the battery cell 3 , the smoke gas generated inside the battery cell 3 can be confined within the closed space 5 .

[0042] The closed space 52 according to the embodiment is positioned on both widthwise outer sides of the electric vehicle when the battery pack 1 is installed inside the passenger compartment of the electric vehicle. Therefore, when the electric vehicle is hit from the side, the closed space 52 collapses, allowing the battery pack 1 to absorb the impact of the side collision.

[0043] The closed space 53 in this embodiment is provided at a position that is at the front of the electric vehicle in the longitudinal direction when the battery pack 1 is installed in the passenger compartment of the electric vehicle. Therefore, when the electric vehicle is hit head-on, the closed space 53 collapses, allowing the battery pack 1 to mitigate the impact of the head-on collision.

[0044] The closed space 54 in the embodiment is provided at a position that is on the rear side of the electric vehicle in the longitudinal direction when the battery pack 1 is installed in the passenger compartment of the electric vehicle. Therefore, when the electric vehicle is hit from behind, the closed space 54 collapses, allowing the battery pack 1 to mitigate the impact of the rear-end collision.

[0045] The closed space 55 of the embodiment is provided at the upper vertical position of the electric vehicle when the battery pack 1 is installed in the passenger compartment of the electric vehicle, so that gas generated inside the battery cell 3 due to an abnormality in the battery cell 3 can be stored in the closed space.

[0046] Furthermore, with the battery pack 1 according to the embodiment, exhaust gas generated inside the battery cell 3 due to an abnormality in the battery cell 3 and flowing into the closed space 51 through the pressure release valve 31 mainly passes through the closed space 54 located at the rear of the electric vehicle in the longitudinal direction, and flows into the closed space 55 located at the upper side in the height direction of the electric vehicle. This allows the contactor 34 to operate normally and the thermal fuse 35 to melt quickly.

[0047] The present invention is not limited to the above-described embodiments, and includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0048] REFERENCE SIGNS LIST 1 Battery pack 2 Battery case 21 Tray 22 Cover 23 Air inlet 24 Air outlet 25 Duct 26-29 Foam seal 3 Battery cell 31 Pressure release valve 32 Battery module 34 Contactor 35 Thermal fuse 4 Open space 41 Storage space 42 Air inlet path 43 Air outlet path 5 Closed space 51 Closed space provided between battery modules 52 Closed spaces provided on both outer sides in the vehicle width direction of the electric vehicle 53 Closed space provided at a position on the front side in the fore-and-aft direction of the electric vehicle 54 Closed space provided at a position on the rear side in the fore-and-aft direction of the electric vehicle 55 Closed space provided at a position on the upper side in the height direction of the electric vehicle 6 Blower fan 7 Duct

Claims

1. A battery pack in which battery cells are housed within a battery case, wherein the battery case has an open space that communicates with the outside of the battery case at at least two different locations, and a closed space that is isolated from the outside of the battery case and the open space, and the battery cells are installed in the open space and have pressure release valves that communicate between the inside of the battery cells and the closed space.

2. The battery pack according to claim 1, wherein the volume of the closed space is greater than the volume of smoke gas generated inside the battery cell.

3. The battery pack according to claim 1 or 2, wherein the closed space is provided at a position on both outer sides in the width direction of the electric vehicle when the battery pack is installed in the passenger compartment of the electric vehicle.

4. The battery pack according to claim 1 or 2, wherein the closed space is provided at a position that is on the front side of the electric vehicle in the longitudinal direction when the battery pack is installed in the passenger compartment of the electric vehicle.

5. The battery pack according to claim 1 or 2, wherein the closed space is provided at a position that is rearward in the longitudinal direction of the electric vehicle when the battery pack is installed in the passenger compartment of the electric vehicle.

6. The battery pack according to claim 1 or 2, wherein the enclosed space is provided at a position that is on the upper side in the height direction of the electric vehicle when the battery pack is installed in the passenger compartment of the electric vehicle.

7. A battery pack according to claim 1 or 2, wherein the closed spaces are provided at positions that are in front and rear of the electric vehicle when the battery pack is installed in the passenger compartment of the electric vehicle, and at a position that is in communication with the rear position and is above the height of the electric vehicle, and the closed space provided at the front position is provided with a contactor that cuts off the flow of electricity between the outside and inside of the battery pack, while the closed space provided at the rear position is provided with a temperature fuse that cuts off the flow of electricity to the battery cells.

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