JP6331017B2 - Battery cooling system - Google Patents

Description

  The present invention relates to a battery cooling device that cools a battery in a battery pack by allowing air to pass through the battery pack.

Some vehicles equipped with a high-capacity, high-power battery such as an electric vehicle or a hybrid vehicle are equipped with a battery temperature control device for controlling the temperature of the battery. As a battery temperature control device, for example, an air-cooling type cooling device is known which cools air such as outside air by passing it through a battery pack containing a plurality of batteries.
For example, in Patent Document 1, an air inlet and an exhaust port are provided in a battery pack (battery box), and air is forcibly introduced into the inlet by a fan to cool a battery (battery) in the battery pack. A cooling device having a structure for discharging air from an exhaust port is disclosed.

JP 2008-254627 A

In a vehicle that cools a battery by introducing air into the battery pack as in Patent Document 1, the vehicle is provided with an opening / closing valve in at least one of the introduction port and the exhaust port, and the opening / closing valve is closed when the temperature of the battery decreases. In some cases, the valve is opened when the temperature of the battery rises, and the fan is operated to introduce air to cool the battery in the battery pack.
However, in the cooling device having the on-off valve and the fan as described above, when combustible gas is generated from the battery due to thermal runaway of the battery, the battery pack should be cooled when the combustible gas is filled in the battery pack. When the on-off valve is opened and the cooling fan is operated, there is a risk of sudden ignition and combustion due to the supply of a large amount of air into the battery pack.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a battery cooling device that improves safety when the battery is cooled during thermal runaway.

  In order to achieve the above object, a battery cooling device according to claim 1 is a battery cooling device for cooling a battery accommodated in a battery pack, and is provided in a lower portion of the battery pack. An introduction port for introducing air into the battery pack, an exhaust port provided at the top of the battery pack for discharging air from the battery pack, a first opening / closing means for opening and closing the introduction port, and a first opening and closing unit for opening and closing the exhaust port. 2 open / close means, control means for controlling open / close states of the first and second open / close means, and a thermal runaway detector for detecting thermal runaway of the battery, the control means comprising the thermal runaway When a thermal runaway of the battery is detected by a detector, the first opening and closing means are closed to close the introduction port, and the second opening and closing means are opened to open the exhaust port. The first time after a predetermined time has elapsed Characterized in that for opening the inlet open closing means.

The battery cooling device according to claim 2 is the battery cooling device according to claim 1, wherein the battery pack contains a plurality of the batteries, and the thermal runaway detector detects thermal runaway for each of the plurality of batteries, and the control is performed. The means is further characterized in that the predetermined time is increased as the number of the batteries in which the thermal runaway is detected increases.
According to a third aspect of the present invention, there is provided the battery cooling apparatus according to the first or second aspect, wherein the thermal runaway detector detects the thermal runaway based on a temperature of the battery.

According to a fourth aspect of the present invention, there is provided the battery cooling apparatus according to the first or second aspect, wherein the thermal runaway detector detects the thermal runaway based on a voltage of the battery.
According to a fifth aspect of the present invention, there is provided the battery cooling device according to any one of the first to fourth aspects, wherein a flow passage for flowing air in the battery pack is formed at a lower portion of the battery, It is arranged below the battery.

  According to the battery cooling device of claim 1, even when flammable gas is generated from the battery when the battery is thermally runaway, the exhaust port provided in the upper part of the battery pack opens, so that the combustible gas is discharged from the exhaust port. Sexual gas is discharged. At this time, since the introduction port provided in the lower part of the battery pack is closed, a large amount of air is prevented from being introduced into the battery pack. Therefore, even if the exhaust port opens with a large amount of combustible gas generated from a thermal runaway battery, it prevents ignition and combustion of combustible gas in the battery pack, improving safety. Can be made.

Then, when the flammable gas concentration in the battery pack decreases after a predetermined time has passed, the intake port is opened to prevent ignition and combustion of the flammable gas in the battery pack, and the battery cooling Can be promoted, and further thermal runaway can be suppressed.
According to the battery cooling device of claim 2, the predetermined time is increased as the number of batteries that are thermally runaway increases, so that the number of batteries that are thermally runaway is combustible in the battery pack at most. It is possible to open the inlet after sufficiently discharging the volatile gas, and to prevent ignition and combustion of the flammable gas in the battery pack and improve safety.

According to the battery cooling device of claim 3, it is possible to determine whether or not a thermal runaway occurs based on the temperature of the battery, and the battery pack is controlled by the operation control of the first opening / closing means and the second opening / closing means. In addition to preventing ignition and combustion of combustible gas, the battery can be cooled to prevent further thermal runaway.
According to the battery cooling device of claim 4, it is possible to determine whether or not the thermal runaway occurs based on the voltage of the battery, and the battery pack is controlled by the operation control of the first opening and closing means and the second opening and closing means. In addition to preventing ignition and combustion of combustible gas, the battery can be cooled to prevent further thermal runaway.

  According to the battery cooling device of the fifth aspect, since the outside air that has entered the battery pack from the inlet port reliably hits the lower part of the battery when flowing toward the exhaust port, the battery can be efficiently cooled.

It is a schematic block diagram of the cooling device of the battery which concerns on one Embodiment of this invention. It is a bottom view of the battery pack which shows the position of the inlet in this embodiment. It is a top view of the battery pack which shows the position of the exhaust port in this embodiment. It is a flowchart which shows the operating point of the cooling device at the time of the thermal runaway in this embodiment. It is a graph for demonstrating the setting point of intake valve opening timing.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a battery cooling device according to an embodiment of the present invention. FIG. 2 is a bottom view of the battery pack showing the position of the inlet in the present embodiment. FIG. 3 is a top view of the battery pack showing the position of the exhaust port in the present embodiment.
The battery cooling device 1 according to the present embodiment is applied to a vehicle equipped with a battery that outputs electric power to a travel drive motor, such as an electric vehicle or a plug-in hybrid vehicle.

As shown in FIGS. 1 to 3, the battery pack 2 mounted on the vehicle has a plurality of battery modules 4 accommodated in a case 3 side by side. In the present embodiment, four battery modules 4 are accommodated in the battery pack 2. The battery module 4 is configured by arranging a plurality of battery cells 4a.
In the battery pack 2, adjacent battery modules 4 are spaced apart from each other, and air flow paths 5 are formed between the battery modules 4 and between the upper and lower parts of the battery module 4. In the upper and lower portions of the battery pack 2, there are an inlet 6 for introducing air (outside air) from the outside into the battery pack 2 and an exhaust port 7 for discharging the air in the battery pack 2 to the outside. Is provided.

As shown in FIG. 2, a plurality of introduction ports 6 are provided on the lower surface of the case 3 of the battery pack 2, and are arranged so as to overlap each battery module 4 in the vertical direction at a position below each battery module 4. In the present embodiment, two introduction ports 6 are provided at equal intervals for each battery module 4, and a total of eight introduction ports 6 are provided in the battery pack 2.
On the other hand, as shown in FIG. 3, a plurality of exhaust ports 7 are provided on the upper surface of the case 3 of the battery pack 2, and are arranged in accordance with the positions of the flow paths 5 between the adjacent battery modules 4. In the present embodiment, a total of three exhaust ports 7 are provided in a line in the approximate center of the battery pack 2. The opening area of the exhaust port 7 is set larger than the opening area of the introduction port 6.

The battery pack 2 is provided with an intake valve 12 (first opening / closing means) for opening and closing the introduction port 6 for each introduction port 6 and an exhaust valve 13 (second opening / closing means) for opening and closing the exhaust port 7. Is provided for each exhaust port 7.
When both the intake valve 12 and the exhaust valve 13 are opened, the warmed air in the battery pack 2 moves upward in the flow path 5 and is discharged from the exhaust port 7, and outside air is discharged from the introduction port 6 to the battery pack 2. Into the inside. That is, the outside air introduced from the introduction port 6 exchanges heat with the battery module 4 that has reached a high temperature and is discharged from the exhaust port 7, thereby cooling the battery module 4. At this time, since the introduction port 6 is arranged below the battery module 4, the air flowing from the introduction port 6 toward the exhaust port 7 always hits the lower part of the battery module 4. Therefore, the outside air introduced into the battery pack 2 can reliably and efficiently cool the battery module 4 by flowing not only from the flow path 5 but also through the gaps between the battery cells 4a of the battery module 4 from below.

The intake valve 12 and the exhaust valve 13 are controlled by a cell management unit 20 (control means) mounted on the vehicle.
Each battery module 4 in the battery pack 2 is provided with a temperature sensor 21 (thermal runaway detector) that detects the temperature of each battery module 4.
The cell management unit 20 includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), a timer, and the like. The temperature of the battery module 4 is measured from each temperature sensor 21. The intake valve 12 and the exhaust valve 13 are controlled to be input.

The cell management unit 20 closes the intake valve 12 and the exhaust valve 13 when the temperature of all the battery modules 4 is within the allowable range when the vehicle power is turned off.
FIG. 4 is a flowchart showing the operating procedure of the cooling device 1 during the thermal runaway executed in the cell management unit 20 of the present embodiment. FIG. 5 is a graph for explaining the procedure for setting the valve opening timing of the intake valve 12.

This control is repeatedly executed when the vehicle power is turned on.
First, in step S10, normal cooling is performed. In the normal cooling, when the temperature of the battery module 4 is lower than the upper limit value of the allowable range and the temperature in the battery pack 2 becomes equal to or higher than a predetermined temperature T1 set appropriately, the intake valve 12 and the exhaust valve 13 are opened as described above. In this control, the outside air is passed through the battery pack 2 to cool the battery pack 2, that is, the battery module 4. When the temperature of the battery module 4 is lower than the predetermined temperature T1, the intake valve 12 and the exhaust valve 13 are closed. Then, the process proceeds to step S20.

  In step S20, it is determined whether there is a thermal runaway cell. If there is a thermal runaway in at least one battery module 4 among the plurality of battery modules 4, the process proceeds to step S30. If there is no thermal runaway in all battery modules 4, the process returns to step S20. Whether or not there is thermal runaway may be determined as thermal runaway when the temperature Tc of the battery module 4 input from the temperature sensor 21 of the battery module 4 is higher than a predetermined temperature T2 set in advance. The predetermined temperature T2 may be set to the temperature of the battery module 4 reached at the time of thermal runaway. A voltage sensor 22 (thermal runaway detector) that detects the voltage Vc of each battery module 4 is provided instead of the temperature Tc of the battery module 4, and the voltage Vc detected by the voltage sensor 22 in at least one battery module 4 is It may be determined that there is a thermal runaway when there is a sudden large fluctuation.

In step S30, the intake valve 12 is closed and the exhaust valve 13 is opened. Then, the process proceeds to step S40.
In step S40, an elapsed time Thop after opening the exhaust valve 13 in step 30 is measured, and it is determined whether or not the elapsed time Thop has passed a preset intake valve opening timing Tlop (predetermined time). To do. When the elapsed time Thop after opening the exhaust valve 13 has passed the intake valve opening timing Tlop, the process proceeds to step S50. If the elapsed time Thop has not passed the intake valve opening timing Tlop, the process returns to step S40.

  FIG. 5 shows the battery when the exhaust valve 13 is opened with the intake valve 12 closed from the state where the battery pack 2 of the present embodiment is filled with the combustible gas from the battery module 4. The transition of the combustible gas concentration in the pack 2 is shown. As shown in FIG. 5, even if the intake valve 12 is closed, the combustible gas concentration in the battery pack 2 gradually decreases by opening the exhaust valve 13. Then, after the exhaust valve 13 is opened, an elapsed time in which the combustible gas concentration in the battery pack 2 falls below the lower limit value of the combustible concentration (concentration for ignition and combustion) is confirmed in advance by calculation or experiment, The elapsed time may be set as the intake valve opening timing Tlop.

In step S50, the intake valve 12 is opened. Then, this routine ends.
By controlling as described above, in the present embodiment, the exhaust valve 13 is opened with the intake valve 12 closed when the battery module 4 is in a thermal runaway. As a result, even if flammable gas is generated from the battery module 4 that has run out of heat, the flammable gas is discharged from the exhaust port 7 provided in the upper portion of the battery pack 2. At this time, since the intake valve 12 is closed, inflow of a large amount of air into the battery pack 2 can be suppressed, and the combustible gas in the battery pack 2 can be prevented from being ignited and burned. Can be improved.

  And since the exhaust valve 13 is opened even if the intake valve 12 is closed, the combustible gas concentration in the battery pack 2 gradually decreases and is an elapsed time when the combustible concentration falls below the lower limit value of the combustible concentration. Since the intake valve 12 is opened after the intake valve opening timing Tlop has elapsed, the ignition of the combustible gas is prevented and the cooling of the battery module 4 is promoted after the intake valve 12 is opened. Thermal runaway can be suppressed.

In this embodiment, since the battery module 4 is cooled by opening the intake valve 12 and the exhaust valve 13 without using a cooling fan, the power consumption is suppressed and the output from the battery pack 2 is caused by thermal runaway. However, if the intake valve 12 and the exhaust valve 13 are once opened, cooling is possible.
In addition, this invention is not limited to the said embodiment.

  For example, in the above embodiment, the intake valve opening timing Tlop is set as one set value corresponding to the battery pack 2, but a plurality of intake valve opening timings Tlop may be provided. Specifically, in step S20, when determining whether or not the battery module 4 is thermally runaway, the number of battery modules 4 that are thermally runaway is determined, and the intake valve opening timing Tlop is changed according to the number. That's fine. When the number of battery modules 4 that are thermally runaway is large, it is expected that a large amount of combustible gas is generated. Therefore, if the elapsed time after opening the exhaust valve 13 is not increased, the battery There is a possibility that the combustible gas concentration in the pack 2 does not fall below the lower limit of the combustible concentration. Accordingly, the larger the number of battery modules 4 that are running out of heat, the slower the intake valve opening timing Tlop, that is, the time from opening the exhaust valve 13 to opening the intake valve 12 is set to increase. do it.

  As a result, even if the number of battery modules 4 that are in a thermal runaway state is large, the intake valve 12 can be opened in a state where the combustible gas concentration in the battery pack 2 is below the lower limit value of the combustible concentration. Thus, it is possible to prevent the combustible gas from being ignited and burned when the valve 12 is opened, thereby improving safety. Further, when the number of battery modules 4 that are in thermal runaway is small, the intake valve opening timing Tlop can be set as early as possible, and thermal runaway can be suppressed more quickly.

  Further, not only the outside air but also air cooled by the vehicle air conditioner may be introduced as the air to be introduced into the battery pack 2. Further, various structures such as the shape and arrangement of the battery pack 2 may be appropriately changed. The present invention can also be applied to batteries other than those for supplying power to the driving motor, even for batteries mounted in various vehicles and other uses, with respect to battery packs that contain batteries inside. Can be widely applied.

DESCRIPTION OF SYMBOLS 1 Cooling device 2 Battery pack 4 Battery module (battery)
5 Flow passage 6 Inlet 7 Exhaust 12 Inlet valve (first opening / closing means)
13 Exhaust valve (second opening / closing means)
20 Cell management unit (control means)
21 Temperature sensor (thermal runaway detector)
22 Voltage sensor (thermal runaway detector)

Claims (5)

A battery cooling device for cooling a battery housed in a battery pack,
An inlet provided in the lower part of the battery pack for introducing air into the battery pack;
An exhaust port provided at an upper portion of the battery pack for exhausting air from the battery pack;
First opening and closing means for opening and closing the inlet;
Second opening and closing means for opening and closing the exhaust port;
Control means for controlling the open / closed state of the first and second open / close means;
A thermal runaway detector for detecting thermal runaway of the battery,
When the thermal runaway detector detects the thermal runaway of the battery, the control means closes the first opening / closing means to close the introduction port, and opens the second opening / closing means to A battery cooling device comprising: opening the exhaust opening and then opening the introduction port by opening the first opening / closing means after a predetermined time has elapsed. The battery pack contains a plurality of the batteries,
The thermal runaway detector detects thermal runaway for each of the plurality of batteries,
2. The battery cooling device according to claim 1, wherein the control unit further increases the predetermined time as the number of the batteries in which the thermal runaway is detected increases.   3. The battery cooling device according to claim 1, wherein the thermal runaway detector detects the thermal runaway based on a temperature of the battery. 4.   3. The battery cooling apparatus according to claim 1, wherein the thermal runaway detector detects the thermal runaway based on a voltage of the battery.   The flow path through which the air in a battery pack flows is formed in the lower part of the said battery, The said inlet is arrange | positioned under the said battery, The any one of Claim 1 to 4 characterized by the above-mentioned. The battery cooling device according to Item.

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