Battery pack thermal runaway protection system and vehicle

Abstract

The application discloses a battery pack thermal runaway protection system and a vehicle. The battery pack thermal runaway protection system comprises a refrigeration device, a control valve group, a refrigerant circulation pipeline and a battery cooling plate. The refrigeration device is used for refrigerating refrigerant in the refrigerant circulation pipeline. The control valve group is arranged on the refrigerant circulation pipeline. The refrigerant circulation pipeline is communicated with the battery cooling plate. The battery cooling plate is used for dissipating heat of the battery pack. A controller is connected with the control valve group and the refrigeration device. The controller is configured to acquire a temperature value of the battery pack, determine a temperature change rate of the battery pack according to the temperature value, and control an on-off state of the control valve group and a working state of the refrigeration device according to the temperature value and / or the temperature change rate. The system can not only realize thermal runaway protection of the battery pack, but also improve the accuracy of the thermal runaway protection. In addition, the system does not need to increase a new structure and has low cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a battery pack thermal runaway protection system and a vehicle. BACKGROUND

[0002] In the related art, in order to solve the problem of battery pack thermal diffusion, a special battery pack thermal diffusion prevention device is usually arranged, but the device occupies a large space in the vehicle, the control mode is complex, and the chemical substances in the device are prone to deterioration. In addition, the control mode only uses temperature as the determination standard, and the temperature may not match the real situation of the battery pack thermal runaway. SUMMARY

[0003] The present application aims to solve at least one of the technical problems in the existing automobile thermal management technology. To this end, one object of the present application is to provide a battery pack thermal runaway protection system, which can not only achieve thermal runaway protection of the battery pack, but also improve the accuracy of thermal runaway protection, and does not need to increase new structures, and has low cost.

[0004] A second object of the present application is to provide a vehicle.

[0005] To solve the above problems, the first aspect of the present application provides a battery pack thermal runaway protection system, comprising: a refrigeration device, a control valve group, a refrigerant circulation pipeline and a battery cooling plate, the refrigeration device is used for refrigerating the refrigerant in the refrigerant circulation pipeline, the control valve group is arranged on the refrigerant circulation pipeline, the refrigerant circulation pipeline is communicated with the battery cooling plate, and the battery cooling plate is used for heat dissipation of the battery pack; a controller, the controller is connected with the control valve group and the refrigeration device, and the controller is configured to: acquire a temperature value of the battery pack; determine a temperature change rate of the battery pack according to the temperature value; and control the opening and closing state of the control valve group and the working state of the refrigeration device according to the temperature value and / or the temperature change rate.

[0006] The battery pack thermal runaway protection system according to the embodiment of the present application, based on the refrigeration device, refrigerates the refrigerant in the refrigerant circulation pipeline, and communicates the refrigerant circulation pipeline with the battery cooling plate. The heat dissipation function of the battery pack is realized by using the existing refrigeration device in the vehicle, so that a new thermal diffusion prevention device is not needed, the space occupied in the vehicle is saved, and the cost is reduced. In addition, when the battery pack is protected from thermal runaway, not only the temperature value of the battery pack is considered, but also the temperature change rate of the battery pack is introduced, that is, the thermal runaway of the battery pack is judged from two aspects of the temperature value and the temperature change rate of the battery pack. Therefore, the thermal runaway protection function of the battery pack can be realized, the detection of the thermal runaway of the battery pack can be effectively ensured to match the real situation, and the accuracy of the thermal runaway protection is improved.

[0007] The second aspect embodiment of the present application provides a vehicle, comprising: a battery pack; and the battery pack thermal runaway protection system according to the above-mentioned embodiments, which is connected with the battery pack to protect the battery pack from thermal runaway.

[0008] According to the vehicle of the embodiment of the present application, the battery pack thermal runaway protection system provided by the above-mentioned embodiments is adopted, so that the thermal runaway protection of the battery pack can be realized, the accuracy of the thermal runaway protection can be improved, and no new structure needs to be added, thereby reducing the cost.

[0009] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0010] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the appended drawings.

[0011] Figure 1 is a structural block diagram of a battery pack thermal runaway protection system according to an embodiment of the present application;

[0012] Figure 2 is a control flow diagram of a battery pack thermal runaway protection system according to an embodiment of the present application;

[0013] Figure 3 is a structural schematic diagram of a battery pack thermal runaway protection system according to an embodiment of the present application;

[0014] Figure 4 is a control flow diagram of a battery pack thermal runaway protection system according to another embodiment of the present application;

[0015] Figure 5 is a structural block diagram of a vehicle according to an embodiment of the present application.

[0016] REFERENCE NUMERALS:

[0017] Battery pack thermal runaway protection system 100; vehicle 200;

[0018] Refrigeration device 1; control valve group 2; refrigerant circulation pipeline 3; battery cooling plate 4; controller 5; second liquid storage tank 6;

[0019] First cooling circuit 31; second cooling circuit 32; third cooling circuit 33; compressor 11; condenser 12; first liquid storage tank 13; evaporator 14; first solenoid shut-off valve 21; second solenoid shut-off valve 22; three-way valve 23; first electronic expansion valve 24; second electronic expansion valve 25; third electronic expansion valve 26; pressure relief solenoid valve 27; third solenoid shut-off valve 28; battery pack 10. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0021] To address the aforementioned problems, the first aspect of this invention proposes a battery pack thermal runaway protection system. This system not only enables thermal runaway protection of the battery pack but also improves the accuracy of thermal runaway protection. Furthermore, it eliminates the need for additional structures and is cost-effective.

[0022] The following is for reference. Figure 1 The battery pack thermal runaway protection system described in this invention embodiment is as follows: Figure 1 As shown, the battery pack thermal runaway protection system 100 includes a refrigeration unit 1, a control valve group 2, a refrigerant circulation pipeline 3, a battery cooling plate 4, and a controller 5.

[0023] The refrigeration unit 1 is used to cool the refrigerant in the refrigerant circulation pipeline 3. The control valve assembly 2 is located on the refrigerant circulation pipeline 3, which is connected to the battery cooling plate 4. The battery cooling plate 4 is used to dissipate heat from the battery pack. Thus, in the event of thermal runaway of the battery pack, the refrigeration unit 1 cools the refrigerant in the refrigerant circulation pipeline 3. Since the refrigerant circulation pipeline 3 is connected to the battery cooling plate 4, the refrigerant enters the battery cooling plate 4, and the battery cooling plate 4 dissipates heat from the battery pack using the refrigerant. Based on the above design, the existing refrigeration unit 1 in the vehicle is used to achieve the function of dissipating heat from the battery pack, thereby eliminating the need to add a new heat dissipation prevention device, saving interior space and reducing costs.

[0024] In some embodiments, the refrigeration device 1 can be a vehicle air conditioner.

[0025] Controller 5 is connected to control valve group 2 and refrigeration unit 1, wherein, reference Figure 2 As shown, controller 5 is configured to perform the following steps.

[0026] Step S1: Obtain the temperature value of the battery pack.

[0027] In considering the uneven surface temperature of the battery pack, the temperature value of the battery pack can be the maximum temperature value of the battery pack surface, the minimum temperature value of the battery pack surface, or the average temperature value of the battery pack surface, without any restrictions.

[0028] Step S2: Determine the rate of temperature change of the battery pack based on the temperature value.

[0029] The rate of temperature change of the battery pack is the speed at which the temperature of the battery pack increases.

[0030] Specifically, the temperature value of the battery pack can be monitored and recorded in real time over a certain period of time, and the real-time temperature value can be analyzed to obtain the rate of temperature change of the battery pack.

[0031] Step S3: Control the on / off state of the control valve group and the working state of the refrigeration unit according to the temperature value and / or the rate of temperature change.

[0032] In this application, to ensure that the thermal runaway detection of the battery pack matches its actual situation, the thermal diffusion inside the battery pack is determined by two aspects: temperature value and temperature change rate. This not only realizes the thermal runaway protection function of the battery pack, but also effectively improves the accuracy of thermal runaway protection.

[0033] The battery pack thermal runaway protection system 100 according to an embodiment of the present invention uses a refrigeration device 1 to cool the refrigerant in the refrigerant circulation pipeline 3 and connects the refrigerant circulation pipeline 3 to the battery cooling plate 4. By utilizing the existing refrigeration device 1 in the vehicle, the system achieves heat dissipation for the battery pack, eliminating the need for additional heat dissipation prevention devices, thus saving space and reducing costs. Furthermore, when performing thermal runaway protection on the battery pack, not only is the temperature value of the battery pack considered, but also the rate of temperature change. That is, the thermal runaway situation of the battery pack is judged from both the temperature value and the rate of temperature change. This not only achieves the thermal runaway protection function but also effectively ensures that the detected thermal runaway situation matches the actual situation, improving the accuracy of the thermal runaway protection.

[0034] In some embodiments, the refrigerant circulation pipeline 3 includes a first cooling circuit 31 for dissipating heat from the battery pack and a second cooling circuit 32 for cooling the passenger compartment. A battery cooling plate 4 is disposed on the first cooling circuit 31 and is connected to the first cooling circuit 31. The refrigeration device 1 is disposed on the second cooling circuit 32. Thus, the design based on two cooling circuits facilitates separate control of cooling of the passenger compartment and heat dissipation of the battery pack.

[0035] The following is based on Figure 3 The battery pack thermal runaway protection system 100 shown is used as an example for specific explanation. The refrigeration device 1 includes a compressor 11, a condenser 12, a first liquid storage tank 13 and an evaporator 14 arranged sequentially on the second cooling circuit 32.

[0036] In addition, the control valve group 2 includes a first solenoid shut-off valve 21, a second solenoid shut-off valve 22, a three-way valve 23, a first electronic expansion valve 24, a second electronic expansion valve 25, and a third electronic expansion valve 26.

[0037] The first electromagnetic shut-off valve 21 is located between the compressor 11 and the condenser 12; the first valve port of the second electromagnetic shut-off valve 22 is connected to the first liquid storage tank 13; the first valve port of the three-way valve 23 is connected to the second valve port of the second electromagnetic shut-off valve 22; the first valve port of the first electronic expansion valve 24 is connected to the second valve port of the three-way valve 23, and the second valve port of the first electronic expansion valve 24 is connected to the evaporator 14; the first valve port of the second electronic expansion valve 25 is connected to the third valve port of the three-way valve 23, and the second valve port of the second electronic expansion valve 25 is connected to the liquid inlet of the battery cooling plate 4; the first valve port of the third electronic expansion valve 26 is connected to the liquid outlet of the battery cooling plate 4, and the second valve port of the third electronic expansion valve 26 is connected to the suction port of the compressor 11.

[0038] refer to Figure 3 As shown, under normal operating conditions, the battery pack thermal runaway protection system 100 can normally cool the passenger compartment and dissipate heat from the battery pack. The flow path of the refrigerant through the evaporator 14 to absorb heat is the second cooling circuit 32, and the flow path of the refrigerant through the battery cooling plate 4 to absorb heat is the first cooling circuit 31.

[0039] Specifically, high-temperature, high-pressure gaseous refrigerant is discharged from compressor 11 and enters condenser 12. After being cooled by condenser 12, the gaseous refrigerant becomes low-temperature, high-pressure liquid refrigerant. Then, it is throttled by control valve group 2 to become low-temperature, low-pressure two-phase refrigerant. After absorbing heat through evaporator 14 or battery cooling plate 4 in the passenger compartment, it changes from liquid refrigerant to low-temperature, low-pressure gaseous refrigerant and is drawn back into compressor 11. The refrigerant distribution method is regulated by three-way valve 23 regardless of whether it passes through evaporator 14 or battery cooling plate 4. Therefore, based on the above design, the existing refrigeration device 1 in the vehicle is used to achieve the heat dissipation function of the battery pack, thus eliminating the need for additional heat diffusion prevention devices, saving interior space and reducing costs.

[0040] It should be noted that, for the battery pack thermal runaway protection system 100 of this application, the control valve group 2 can be set arbitrarily, provided that the thermal runaway protection function of the battery pack is realized, and is not limited to the above-mentioned setting methods of electromagnetic shut-off valve, three-way valve and electronic expansion valve.

[0041] In some embodiments, for controlling the switching state of the control valve group and the operating state of the refrigeration device based on the temperature value and / or the rate of temperature change, the controller 5 is specifically configured to determine that the temperature value meets a first thermal runaway condition, control the switching state of the control valve group to a first state to conduct a first cooling circuit; and control the refrigeration device to operate at a first operating power, the first operating power being lower than the maximum allowable operating power of the refrigeration device.

[0042] In other words, when the temperature value meets the first thermal runaway condition, it indicates that the battery pack has reached the boundary of thermal runaway. Therefore, to prevent further thermal diffusion of the battery pack, the control valve group 2 is switched to the first state to open the first cooling circuit 31. This allows the refrigerant cooled by the refrigeration device 1 to be introduced into the battery cooling plate 4 through the first cooling circuit 31, so that the battery cooling plate 4 can dissipate heat from the battery pack using the refrigerant. Simultaneously, since the battery pack thermal runaway protection system 100 is powered by the battery pack, considering the battery pack's power consumption, the refrigeration device 1 must be controlled to operate at a first operating power lower than the maximum allowable operating power when cooling the battery pack. This achieves both thermal runaway protection for the battery pack and saves power consumption.

[0043] The maximum allowable operating power of the refrigeration unit 1 can be set based on actual conditions and is not limited thereto. For example, the maximum allowable operating power W0 can be 3 kW.

[0044] In some embodiments, for determining that a temperature value satisfies a first thermal runaway condition, the controller is specifically configured to determine that the temperature value is greater than or equal to a first temperature threshold and less than a second temperature threshold, for example, it can be denoted as: first temperature threshold T0 ≤ temperature value T < second temperature threshold Ta.

[0045] The first or second temperature threshold can be preset based on actual conditions, and there are no restrictions on this. For example, the first temperature threshold can be set to 65℃, and the second temperature threshold can be set to 90℃.

[0046] In some embodiments, reference Figure 3 As shown, in the first state, the first electromagnetic shut-off valve 21 is open, the second electromagnetic shut-off valve 22 is open, the first and second ports of the three-way valve 23 are connected, the first and third ports of the three-way valve 23 are connected, the first electronic expansion valve 24 is open, the second electronic expansion valve 25 is open, and the third electronic expansion valve 26 is open. This method controls the on / off state of the control valve group 2, ensuring that all components in the battery pack thermal runaway protection system 100 operate under normal cooling conditions. This satisfies both the cooling requirements of the passenger compartment and provides thermal runaway protection for the battery pack.

[0047] In some embodiments, for controlling the switching state of the control valve group and the operating state of the refrigeration device based on the temperature value and / or the rate of temperature change, the controller is specifically configured to determine that the temperature value and the rate of temperature change satisfy a second thermal runaway condition, control the switching state of the control valve group to a second state to open the first cooling circuit and close the second cooling circuit; and control the refrigeration device to operate at the maximum permissible operating power.

[0048] In other words, when the temperature value and the rate of temperature change meet the second thermal runaway condition, it indicates that the temperature of the battery pack is continuously rising. Therefore, in order to prevent the thermal diffusion of the battery pack as soon as possible, the switching state of the control valve group 2 is set to the second state to open the first cooling circuit 31 and close the second cooling circuit 32. That is, the refrigeration device 1 no longer provides cooling capacity to the passenger compartment, but instead inputs all the cooling capacity into the first cooling circuit 31 to cool and dissipate heat from the battery pack. At the same time, the refrigeration device 1 is controlled to operate at the maximum allowable operating power to further improve the heat dissipation efficiency.

[0049] In some embodiments, for determining that the temperature value and the rate of temperature change satisfy the second thermal runaway condition, the controller 5 is specifically configured to determine that the temperature value is greater than or equal to a first temperature threshold and less than a second temperature threshold, and the rate of temperature change is greater than or equal to a first preset rate and less than a second preset rate, for example, it can be recorded as: first temperature threshold T0 ≤ temperature value T < second temperature threshold Ta & first preset rate θ0 ≤ temperature change rate θ < second preset rate θa.

[0050] The first or second preset rate can be preset based on actual conditions, and there are no restrictions on this. For example, the first preset rate can be set to 0.01℃ / s, and the second preset rate can be set to 0.015℃ / s.

[0051] In some embodiments, in the second state, the first electromagnetic shut-off valve 21 is open, the second electromagnetic shut-off valve 22 is open, the first and second ports of the three-way valve 23 are closed, the first and third ports of the three-way valve 23 are open, the first electronic expansion valve 24 is closed, the second electronic expansion valve 25 is open, and the third electronic expansion valve 26 is open. This controls the switching state of the control valve group 2, causing the three-way valve 23 to fully open the first cooling circuit 31 and completely close the second cooling circuit 32. Consequently, the cooling device 1 no longer provides cooling to the passenger compartment and only provides cooling to the battery pack, thereby increasing the cooling capacity in the first cooling circuit 31 and effectively improving heat dissipation efficiency.

[0052] In some embodiments, for controlling the switching state of the control valve group and the operating state of the refrigeration unit based on the temperature value and / or the rate of temperature change, the controller is specifically configured to determine that the temperature value meets the third thermal runaway condition, control the switching state of the control valve group to the third state, and control the refrigeration unit to operate at the maximum permissible operating power to control the first liquid receiver to recover refrigerant from the refrigerant circulation pipeline.

[0053] In other words, when the temperature value meets the third thermal runaway condition, it means that the temperature value of the battery pack is still rising, and the above control method has limited the heat dissipation effect of the battery pack. In this application, the switching state of the control valve group 2 is controlled to the third state, and the refrigeration device 1 is controlled to operate at the maximum allowable operating power immediately, so that the first liquid storage tank 13 can recover the refrigerant in the refrigerant circulation pipeline as soon as possible, thereby facilitating the rapid cooling of the battery pack with all the stored refrigerant.

[0054] In some embodiments, for determining that the temperature value satisfies the third thermal runaway condition, the controller is specifically configured to determine that the temperature value is greater than or equal to the second temperature threshold and less than the third temperature threshold, for example, it can be denoted as: the second temperature threshold Ta ≤ the temperature value T < the third temperature threshold Tb.

[0055] The third temperature threshold can be preset based on actual conditions and is not restricted. For example, the third temperature threshold can be set to 100℃.

[0056] In some embodiments, in the third state, the first electromagnetic shut-off valve 21 is open, the second electromagnetic shut-off valve 22 is closed, the first electronic expansion valve 24 is closed, and the third electronic expansion valve 26 is open. This controls the on / off state of the control valve assembly 2, allowing the compressor 11 to quickly recover the refrigerant from the battery cooling plate 4 into the first liquid storage tank 13, and also to preemptively shut off the second cooling circuit 32 to prevent refrigerant from entering the second cooling circuit 32 when the first cooling circuit 31 is subsequently opened.

[0057] In some embodiments, the controller 5 is further specifically configured to acquire the condenser temperature Tcon and the ambient temperature Te; obtain the temperature difference based on the condenser temperature and the ambient temperature, such as denoted as the temperature difference ΔT = Tcon - Te; and control the switching state of the control valve group and the working state of the refrigeration device based on the temperature difference when the operating time of the refrigeration device reaches a preset time.

[0058] In other words, during refrigerant recovery, the refrigerant is drawn in through the suction port of compressor 11 and enters condenser 12 through the discharge port of compressor 11. During this process, the high-temperature, high-pressure gaseous refrigerant is transformed into a low-temperature, high-pressure liquid refrigerant after being cooled by condenser 12. Therefore, if the refrigerant is still in the recovery state, the condenser temperature will remain at a certain high temperature, that is, the condenser temperature will be significantly higher than the ambient temperature, resulting in a large temperature difference between the condenser temperature and the ambient temperature. However, if the refrigerant recovery is complete, the condenser temperature will gradually decrease, resulting in a gradual decrease in the temperature difference between the condenser temperature and the ambient temperature. Therefore, based on the above principle, this application uses the temperature difference between the condenser temperature and the ambient temperature to determine whether the refrigerant recovery is complete, and then controls the opening and closing status of the control valve group and the working status of the refrigeration device based on the refrigerant recovery status, in order to prepare for subsequent cooling and heat dissipation of the battery pack.

[0059] Furthermore, when performing refrigerant recovery, the influence of time on temperature changes is considered. In this application, after determining that the refrigeration unit has run for a preset duration, the on / off state of the control valve group and the working state of the refrigeration unit are controlled according to the temperature difference. Thus, a certain amount of time can be given to the collected condenser temperature to ensure the accuracy of temperature detection and the accuracy of refrigerant recovery determination.

[0060] The preset duration can be set based on actual conditions, and there are no restrictions on it. For example, the preset duration can be 120 seconds.

[0061] In some embodiments, the battery pack thermal runaway protection system 100 further includes a low-voltage battery. For controlling the switching state of the control valve group and the operating state of the refrigeration device based on the temperature difference, the controller 5 is specifically configured to determine that if the temperature difference is lower than a preset temperature difference threshold, then control the switching state of the control valve group to the fourth state and control the refrigeration device to stop operating; control the battery pack to stop supplying power; and control the low-voltage battery to start supplying power.

[0062] In other words, when the temperature difference is determined to be lower than the preset temperature difference threshold, it indicates that all refrigerant has been recovered in the first liquid storage tank 13. This controls the switch state of the control valve group 2 to the fourth state and controls the refrigeration device 1 to stop operating, that is, controls the compressor 11 to stop running, so as to stop the recovery of refrigerant. In addition, it also controls the battery pack to stop supplying power to prevent the temperature of the battery pack from continuing to rise, and controls the low-voltage battery to start supplying power, that is, all components in the battery pack thermal runaway protection system 100 are switched to be powered by the low-voltage battery.

[0063] In some embodiments, in the fourth state, the first solenoid shut-off valve is closed, the first and second ports of the three-way valve are closed, the first and third ports of the three-way valve are open, and the third electronic expansion valve is closed. This controls the on / off state of the control valve assembly 2 to stop refrigerant recovery and to prepare for cooling the battery pack.

[0064] In some embodiments, after the control battery pack stops supplying power, the controller 5 is further specifically configured to determine that the rate of temperature change meets the fourth thermal runaway condition, control the first liquid reservoir to open and control the switching state of the control valve group to the fifth state, so as to dissipate heat from the battery pack.

[0065] In other words, after the battery pack stops supplying power, if the rate of temperature change meets the fourth thermal runaway condition, it means that the temperature of the battery pack is still rising and the rate of temperature increase is relatively fast. Therefore, the first liquid storage tank 13 is opened and the switch state of the control valve group 2 is controlled to the fifth state so as to use the refrigerant stored in the first liquid storage tank 13 to dissipate heat from the battery pack.

[0066] In some embodiments, for determining that the rate of temperature change satisfies the fourth thermal runaway condition, the controller is specifically configured to determine that the rate of temperature change is higher than a second preset rate, for example, it can be denoted as the second preset rate θa ≤ the rate of temperature change θ.

[0067] In some embodiments, it is understood that if the rate of temperature change is determined to be lower than the second preset rate, it indicates that the heating rate of the battery pack has decreased, the rate of temperature change of the battery pack shows a trend of gradually stabilizing and the temperature value gradually decreasing. Therefore, it is not necessary to open the first liquid storage tank 13 at this time, but the temperature value and / or the rate of temperature change of the battery pack can continue to be judged until the battery pack exits the thermal runaway situation.

[0068] In some embodiments, such as Figure 3 As shown, the control valve assembly 2 also includes a pressure relief solenoid valve 27 for relieving pressure on the battery cooling plate 4. The pressure relief solenoid valve 27 is normally closed, and it will automatically open when the pressure value of the battery cooling plate 4 reaches a certain threshold.

[0069] In some embodiments, such as Figure 3 As shown, the control valve assembly 2 also includes a battery pressure relief valve for depressurizing the battery pack. The battery pressure relief valve is normally closed and automatically opens when the pressure in the battery pack reaches a certain threshold.

[0070] In the fifth state, the first solenoid shut-off valve 21 is closed, the second solenoid shut-off valve 22 is open, the first and second ports of the three-way valve 23 are closed, the first and third ports of the three-way valve 23 are open, the first electronic expansion valve 24 is closed, the second electronic expansion valve 25 is open, the third electronic expansion valve 26 is closed, and the pressure relief solenoid valve 27 is open. This controls the on / off state of the control valve group 2, allowing the refrigerant stored in the first liquid storage tank 13 to enter the battery cooling plate 4 via the first cooling circuit 31, thereby enabling the battery cooling plate 4 to dissipate heat from the battery pack. Simultaneously, considering the possibility of the battery pack bulging due to temperature rise, the battery pressure relief valve is triggered to release gas, and the pressure relief solenoid valve 27 is activated to release pressure from the battery cooling plate 4, preventing the high-temperature gas from the battery pack from flowing back into the first liquid storage tank and causing excessive pressure in the tank.

[0071] In some embodiments, when it is determined that the rate of temperature change meets the fourth thermal runaway condition, the controller 5 controls the opening of the first liquid storage tank and controls the switching state of the control valve group to the fifth state. Specifically, the controller 5 is configured to, when it is determined that the rate of temperature change meets the fourth thermal runaway condition, acquire the refrigerant temperature value in front of the battery cooling plate and the current temperature value of the battery cooling plate; and when it is determined that the refrigerant temperature value is lower than the current temperature value, control the opening of the first liquid storage tank and control the switching state of the control valve group to the fifth state.

[0072] In other words, considering the possibility of the battery pack bulging due to temperature rise and triggering the battery pressure relief valve to release air, in order to avoid the problem of the high-temperature air release from the battery pack causing reverse flow into the first liquid storage tank and resulting in excessive tank pressure, this application uses the refrigerant temperature value in front of the battery cooling plate and the current temperature value of the battery cooling plate to determine whether the current process is in the air release process. If it is determined that the refrigerant temperature value is lower than the current temperature value, it means that the current process is not in the air release process. Therefore, the first liquid storage tank is opened and the switch state of the control valve group is set to the fifth state to dissipate heat from the battery pack.

[0073] In some embodiments, during the heat dissipation process of the battery pack, the controller 5 is further configured to acquire the current pressure value inside the battery cooling plate; if the current pressure value is determined to be lower than a first preset pressure value, the controller controls the switching state of the control valve group to the sixth state.

[0074] Specifically, as the amount of refrigerant gradually decreases, the pressure inside the battery cooling plate 4 will also gradually decrease. Therefore, in order to monitor whether the refrigerant in the first liquid storage tank 13 has been completely released, this application uses real-time monitoring of the current pressure value inside the battery cooling plate 4 to determine whether the refrigerant has been completely released. If the current pressure value is determined to be lower than the first preset pressure value, it indicates that the refrigerant has been completely released. In this case, the switch state of the control valve group 2 is set to the sixth state to stop using the refrigerant in the first liquid storage tank 13 to dissipate heat from the battery pack.

[0075] Furthermore, if the current pressure value is determined to be higher than the first preset pressure value, it indicates that the refrigerant has not been completely released. In this case, the first liquid storage tank 13 is opened, and the switch state of the control valve group 2 is kept in the fifth state to continue to use the refrigerant in the first liquid storage tank 13 to dissipate heat from the battery pack.

[0076] In some embodiments, the first preset pressure value is a value preset based on actual conditions, and there is no limitation thereto. For example, the first preset pressure value can be set to 0.15 MPa.

[0077] In some embodiments, in the sixth state, the second solenoid shut-off valve 22 and the pressure relief solenoid valve 27 are both shut off. This controls the on / off state of the control valve assembly 2 to stop the use of the refrigerant in the first reservoir 13 for cooling the battery pack and to stop the pressure relief from the battery cooling plate 4.

[0078] In some embodiments, the controller 5 is further specifically configured to determine that if the refrigerant temperature is higher than the current temperature, then control the switching state of the control valve group to the seventh state. That is, to avoid backflow caused by excessive pressure within the battery cooling plate 4, this application monitors the refrigerant temperature in real time. If the refrigerant temperature is determined to be higher than the current temperature, it indicates that the venting process is underway. Therefore, the control valve group is switched to the seventh state to stop heat dissipation from the battery pack and prevent pressure backflow.

[0079] In some embodiments, for the refrigerant temperature value, if the ambient temperature Te>0℃, then the refrigerant temperature value Tliq is Te; if the ambient temperature Ten≤0℃, then the refrigerant temperature value Tliq is 0℃.

[0080] In some embodiments, in the seventh state, the second solenoid shut-off valve is shut off, thereby controlling the cooling of the battery pack to stop and preventing pressure backflow.

[0081] In some embodiments, after the control valve group is switched to the seventh state, the controller 5 is further configured to acquire the current pressure value inside the battery cooling plate; if the current pressure value is determined to be lower than the second preset pressure value, then the controller controls the first liquid reservoir to open and the controller controls the control valve group to switch to the fifth state. That is, after the control valve group is switched to the seventh state, the controller determines whether the venting process is complete by monitoring the current pressure value inside the battery cooling plate in real time. If the current pressure value is lower than the second preset pressure value, it indicates that the venting process is complete, thereby controlling the first liquid reservoir to open and the controller controls the control valve group to switch to the fifth state, so as to continue to use the refrigerant in the first liquid reservoir 13 to dissipate heat from the battery pack.

[0082] In some embodiments, the second preset pressure value is a value preset based on actual conditions, and there is no limitation thereto. For example, the second preset pressure value can be set to 0.2 MPa.

[0083] In some embodiments, such as Figure 3 As shown, the battery pack thermal runaway protection system 100 also includes a second liquid reservoir 6, which stores coolant. The refrigerant circulation pipeline 3 also includes a third cooling circuit 33, with the second liquid reservoir 6 located on and connected to the third cooling circuit 33. In other words, the battery pack thermal runaway protection system 100 incorporates two methods for cooling the battery pack: one is using the cooling device 1, and the other is using the second liquid reservoir 6. Therefore, based on these two designs, when the cooling device 1 cannot effectively cool the battery pack, the second liquid reservoir 6 can be used to further enhance the thermal runaway protection function of the battery pack.

[0084] The coolant stored in the second liquid storage tank 6 can be a high-pressure liquid gaseous substance that does not readily undergo chemical reactions, such as carbon dioxide gas, inert gas, or nitrogen gas. There are no restrictions on this.

[0085] In some embodiments, for controlling the switching state of the control valve group and the operating state of the refrigeration device based on the temperature value and / or the rate of temperature change, the controller 5 is specifically configured to determine that the temperature value meets the fifth thermal runaway condition, control the second liquid reservoir to open, and control the switching state of the control valve group to the eighth state to activate the third cooling circuit. Thus, when the refrigeration device 1 cannot effectively dissipate heat from the battery pack, activating the third cooling circuit allows the second liquid reservoir 6 to dissipate heat from the battery pack, thereby further improving the thermal runaway protection function of the battery pack and avoiding the risk of thermal runaway.

[0086] In some embodiments, for determining that the temperature value meets the fifth thermal runaway condition, the controller 5 is specifically configured to determine that the temperature value is greater than or equal to the third temperature threshold, for example, it can be denoted as: the third temperature threshold Tb ≤ the temperature value T.

[0087] In some embodiments, such as Figure 3 As shown, the control valve group 2 also includes a third solenoid shut-off valve 28 and a pressure relief solenoid valve 27.

[0088] The first valve port of the third electromagnetic shut-off valve 28 is connected to the second liquid storage tank 6, and the second valve port of the third electromagnetic shut-off valve 28 is connected to the first valve port of the second electronic expansion valve 25; the pressure relief solenoid valve 27 is used to relieve pressure on the battery cooling plate 4.

[0089] In the eighth state, the first electromagnetic shut-off valve 21 is open, the second electromagnetic shut-off valve 22 is open, the first and second ports of the three-way valve 23 are connected, the first and third ports of the three-way valve 23 are closed, the first electronic expansion valve 24 is open, the second electronic expansion valve 25 is open, the third electronic expansion valve 26 is closed, the third electromagnetic shut-off valve 28 is open, and the pressure relief solenoid valve 27 is open. This controls the switching state of the control valve group 2, thereby enabling the third cooling circuit 33 to be activated, allowing the second liquid reservoir 6 to release coolant to dissipate heat from the battery pack. It also allows the second cooling circuit 32 to be activated in advance to prepare for subsequent cooling of the passenger compartment by the subsequent cooling device 1, prevents the coolant released from the second liquid reservoir 6 from flowing back into the second cooling circuit 32 when the third cooling circuit 33 is activated, and allows for pressure relief of the battery cooling plate 4.

[0090] In some embodiments, considering the problem that the coolant in the second liquid storage tank 6 may become solid in a low-temperature environment, thus preventing the second liquid storage tank 6 from releasing liquid coolant to dissipate heat from the battery pack, in this application, when controlling the second liquid storage tank to open, the controller 5 will obtain the current temperature value of the second liquid storage tank 6. If the current temperature value of the second liquid storage tank 6 is lower than the condensation temperature of the coolant, the temperature of the second liquid storage tank 6 needs to be increased so that the current temperature value of the second liquid storage tank 6 is higher than the condensation temperature of the coolant, thereby ensuring the smooth release of coolant in the second liquid storage tank 6.

[0091] In some embodiments, when it is determined that the temperature value meets the fifth thermal runaway condition, the controller 5 controls the second liquid storage tank to open and controls the control valve group to switch to the eighth state. Specifically, the controller 5 is configured to, when it is determined that the temperature value meets the fifth thermal runaway condition, acquire the refrigerant temperature value in front of the battery cooling plate and the current temperature value of the battery cooling plate; and when it is determined that the refrigerant temperature value is lower than the current temperature value, control the second liquid storage tank to open and control the control valve group to switch to the eighth state.

[0092] In other words, considering the possibility of the battery pack bulging due to temperature rise and triggering the battery pressure relief valve to release air, in order to avoid the problem of the high-temperature air release from the battery pack causing reverse flow into the second liquid storage tank and resulting in excessive tank pressure, this application uses the refrigerant temperature value in front of the battery cooling plate and the current temperature value of the battery cooling plate to determine whether the air release process is in progress. If it is determined that the refrigerant temperature value is lower than the current temperature value, it means that the air release is not currently in progress. Therefore, the second liquid storage tank is opened and the switching state of the control valve group is set to the eighth state, so as to use the coolant released from the second liquid storage tank 6 to dissipate heat from the battery pack.

[0093] In some embodiments, during the heat dissipation process of the battery pack, the controller 5 is further configured to acquire the current pressure value inside the battery cooling plate; if the current pressure value is determined to be lower than a first preset pressure value, the controller controls the switching state of the control valve group to the ninth state.

[0094] Specifically, as the amount of refrigerant gradually decreases, the pressure inside the battery cooling plate 4 will also gradually decrease. Therefore, in order to monitor whether the coolant in the second liquid tank 6 has been completely released, this application uses real-time monitoring of the current pressure value inside the battery cooling plate 4 to determine whether the coolant has been completely released. If the current pressure value is determined to be lower than the first preset pressure value, it indicates that the coolant has been completely released. In this case, the switch state of the control valve group 2 is set to the ninth state to stop using the coolant in the second liquid tank 6 to dissipate heat from the battery pack.

[0095] Furthermore, if the current pressure value is determined to be higher than the first preset pressure value, it indicates that the refrigerant has not been completely released. In this case, the second liquid storage tank 6 is opened, and the switch state of the control valve group 2 is kept in the eighth state to continue to use the coolant in the second liquid storage tank 6 to dissipate heat from the battery pack.

[0096] In some embodiments, in the ninth state, the third solenoid shut-off valve 28 and the pressure relief solenoid valve 27 are shut off. This controls the on / off state of the control valve assembly 2 to stop the use of the coolant in the second reservoir 6 for heat dissipation of the battery pack and to stop the pressure relief of the battery cooling plate 4.

[0097] In some embodiments, the controller 5 is further specifically configured to determine that if the refrigerant temperature is higher than the current temperature, then control the switching state of the control valve assembly to the tenth state. That is, to avoid backflow caused by excessive pressure within the battery cooling plate 4, this application monitors the refrigerant temperature in real time. If the refrigerant temperature is determined to be higher than the current temperature, it indicates that the venting process is underway. Therefore, the switching state of the control valve assembly is controlled to the tenth state to stop heat dissipation from the battery pack and prevent pressure backflow.

[0098] In some embodiments, in the tenth state, the third solenoid shut-off valve 28 is shut off, thereby controlling the cooling of the battery pack to stop and preventing pressure backflow.

[0099] In some embodiments, after the control valve group 2 is switched to the tenth state, the controller 5 is further configured to acquire the current pressure value inside the battery cooling plate; if the current pressure value is determined to be lower than a second preset pressure value, then the controller controls the second reservoir to open and the control valve group to switch to the eighth state. That is, after the control valve group is switched to the tenth state, the controller determines whether the venting process is complete by monitoring the current pressure value inside the battery cooling plate in real time. If the current pressure value is lower than the second preset pressure value, it indicates that the venting process is complete, thereby controlling the second reservoir 6 to open and the control valve group 2 to switch to the eighth state, so as to continue to use the coolant in the second reservoir 6 to dissipate heat from the battery pack.

[0100] The following is a reference appendix. Figure 4 The heat dissipation process of the battery pack in an embodiment of the present invention is illustrated by the following specific steps.

[0101] Step S4: Determine the temperature value T of the battery pack.

[0102] Step S5: Determine whether the first temperature threshold T0 ≤ temperature value T < second temperature threshold Ta is satisfied.

[0103] Step S6: Limit the refrigeration device, such as the vehicle air conditioner, to operate at the maximum allowable operating power W0, and control each component to operate according to normal refrigeration conditions.

[0104] Step S7: Determine whether the first preset rate θ0 ≤ temperature change rate θ < second preset rate θa is satisfied. If yes, proceed to step S8; otherwise, proceed to step S4.

[0105] Step S8: Control the refrigeration unit to operate at the maximum allowable operating power W0, and provide cooling capacity only to the first cooling circuit.

[0106] Step S9: Determine whether the second temperature threshold Ta ≤ temperature value T < third temperature threshold Tb is satisfied.

[0107] Step S10: Control the second electromagnetic shut-off valve to shut off, the first electronic expansion valve to shut off, and the third electronic expansion valve to open, and control the compressor to run at the maximum permissible speed Xr / min.

[0108] Step S11: The controller counts down for a preset duration t1s.

[0109] Step S12: Determine whether the countdown is complete, that is, determine whether the running time of the refrigeration device has reached the preset time.

[0110] Step S13: Determine whether Tcon-Te ≤ preset temperature difference threshold Ts, that is, determine whether the temperature difference ΔT ≤ preset temperature difference threshold Ts.

[0111] In step S14, the control values ​​are as follows: the first electromagnetic shut-off valve is turned off, the third electronic expansion valve is turned off, the three-way valve opens the first cooling circuit and closes the second cooling circuit, the control battery pack stops supplying power, and switches to low-voltage battery power supply.

[0112] Step S15: The controller counts down t2s. t2s can be set to 10s.

[0113] Step S16: Determine whether the temperature change rate θ < the second preset rate θa. If so, proceed to step S4.

[0114] Step S17: Determine whether the temperature change rate θ ≥ the second preset rate θa is satisfied.

[0115] Step S18: Determine whether the refrigerant temperature value Tliq is higher than the current temperature value Texp.

[0116] Step S19: Control the first liquid storage tank to turn on the refrigerant for heat dissipation, and control the second electromagnetic shut-off valve, the second electronic expansion valve, and the pressure relief solenoid valve to turn on.

[0117] Step S20: Control the second solenoid shut-off valve to shut off.

[0118] Step S21: Determine whether the current pressure value P is lower than the first preset pressure value P0. If yes, proceed to step S22; otherwise, proceed to step S18.

[0119] Step S22: Control the second solenoid shut-off valve to shut off and the pressure relief solenoid valve to shut off.

[0120] Step S23: Determine whether the current pressure value P is higher than the second preset pressure value P1. If yes, proceed to step S20; otherwise, proceed to step S18.

[0121] Step S24: Determine whether the third temperature threshold Tb ≤ temperature value T is satisfied.

[0122] Step S25: Determine whether the refrigerant temperature value Tliq is higher than the current temperature value Texp.

[0123] Step S26: Control the second liquid storage tank to start CO2 heat dissipation, and control the three-way valve to shut off the first cooling circuit and open the second cooling circuit, the first electromagnetic shut-off valve to open, the second electromagnetic shut-off valve to open, the third electromagnetic shut-off valve to open, and the pressure relief solenoid valve to open.

[0124] Step S27: Control the third solenoid shut-off valve to shut off.

[0125] Step S28: Determine whether the current pressure value P is lower than the first preset pressure value P0. If yes, proceed to step S29; otherwise, proceed to step S25.

[0126] Step S29: Control the third solenoid shut-off valve to shut off and the pressure relief solenoid valve to shut off.

[0127] Step S30: Determine whether the current pressure value P is higher than the second preset pressure value P1. If yes, proceed to step S27; otherwise, proceed to step S25.

[0128] Furthermore, it should be noted that when the battery pack thermal runaway protection system 100 includes a cooling device 1 and a second liquid storage tank 6, if the cooling device 1 is a CO2 air conditioning unit and the second liquid storage tank 6 stores CO2, the order of control for cooling the battery pack using either the cooling device 1 or the second liquid storage tank 6 is not important. Also, if the amount of refrigerant in the cooling device 1 is sufficient to cool the battery pack, then there is no need to add a second liquid storage tank 6.

[0129] A second aspect of the present invention provides a vehicle, such as Figure 5 As shown, the vehicle 200 includes a battery pack 10 and a battery pack thermal runaway protection system 100 as described in the above embodiment. The battery pack thermal runaway protection system 100 is connected to the battery pack 10 to provide thermal runaway protection for the battery pack 10.

[0130] According to the vehicle 200 of the present invention, by adopting the battery pack thermal runaway protection system 100 provided in the above embodiment, not only can thermal runaway protection of the battery pack 10 be achieved, but the accuracy of thermal runaway protection can also be improved. In addition, no new structure needs to be added, and the cost is low.

[0131] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0132] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery pack thermal runaway protection system, characterized in that, include: The device includes a refrigeration unit, a control valve assembly, a refrigerant circulation pipeline, and a battery cooling plate. The refrigeration unit is used to cool the refrigerant in the refrigerant circulation pipeline. The control valve assembly is located on the refrigerant circulation pipeline. The refrigerant circulation pipeline is connected to the battery cooling plate, and the battery cooling plate is used to dissipate heat from the battery pack. The refrigeration device includes a compressor, a condenser, a first liquid storage tank, and an evaporator arranged sequentially in the second cooling circuit; The refrigerant circulation pipeline includes a first cooling circuit for dissipating heat from the battery pack and a second cooling circuit for cooling the passenger compartment. The battery cooling plate is disposed on the first cooling circuit and is connected to the first cooling circuit. The refrigeration device is disposed on the second cooling circuit. The control valve assembly includes: A first electromagnetic shut-off valve is disposed between the compressor and the condenser; The second electromagnetic shut-off valve, wherein the first valve port of the second electromagnetic shut-off valve is connected to the first liquid storage tank; A three-way valve, wherein the first valve port of the three-way valve is connected to the second valve port of the second electromagnetic shut-off valve; A first electronic expansion valve, wherein the first valve port of the first electronic expansion valve is connected to the second valve port of the three-way valve, and the second valve port of the first electronic expansion valve is connected to the evaporator; The second electronic expansion valve has its first valve port connected to the third valve port of the three-way valve, and its second valve port connected to the liquid inlet of the battery cooling plate. The third electronic expansion valve has its first valve port connected to the liquid outlet of the battery cooling plate and its second valve port connected to the air intake of the compressor. A pressure relief solenoid valve is used to relieve pressure on the battery cooling plate. The controller, connected to the control valve assembly and the refrigeration unit, is configured to: Obtain the temperature value of the battery pack; The rate of temperature change of the battery pack is determined based on the temperature value; The on / off state of the control valve group and the working state of the refrigeration device are controlled according to the temperature value and / or the temperature change rate. The refrigeration device includes a first liquid storage tank disposed on the second cooling circuit. The controller is specifically configured to control the switching state of the control valve group and the operating state of the refrigeration device based on the temperature value and / or the rate of temperature change. Once the temperature value is determined to meet the third thermal runaway condition, the switching state of the control valve group is controlled to the third state, and the refrigeration unit is controlled to operate at the maximum allowable operating power, so as to control the first liquid storage tank to recover the refrigerant in the refrigerant circulation pipeline.

2. The battery pack thermal runaway protection system according to claim 1, characterized in that, The controller is specifically configured to control the on / off state of the control valve assembly and the operating state of the refrigeration unit based on the temperature value and / or the rate of temperature change. Once the temperature value is determined to meet the first thermal runaway condition, the switching state of the control valve group is controlled to the first state to activate the first cooling circuit. The refrigeration device is controlled to operate at a first operating power, which is lower than the maximum allowable operating power of the refrigeration device.

3. The battery pack thermal runaway protection system according to claim 2, characterized in that, For determining that the temperature value satisfies the first thermal runaway condition, the controller is specifically configured as follows: The temperature value is determined to be greater than or equal to a first temperature threshold and less than a second temperature threshold.

4. The battery pack thermal runaway protection system according to claim 2 or 3, characterized in that, In the first state, the first electromagnetic shut-off valve is turned on, the second electromagnetic shut-off valve is turned on, the first valve port of the three-way valve is connected to the second valve port of the three-way valve, the first valve port of the three-way valve is connected to the third valve port of the three-way valve, the first electronic expansion valve is turned on, the second electronic expansion valve is turned on, and the third electronic expansion valve is turned on.

5. The battery pack thermal runaway protection system according to claim 1, characterized in that, The controller is specifically configured to control the on / off state of the control valve assembly and the operating state of the refrigeration unit based on the temperature value and / or the rate of temperature change. If the temperature value and the rate of temperature change are determined to satisfy the second thermal runaway condition, the switching state of the control valve group is controlled to the second state to open the first cooling circuit and close the second cooling circuit. Control the refrigeration unit to operate at its maximum permissible operating power.

6. The battery pack thermal runaway protection system according to claim 5, characterized in that, For determining that the temperature value and the rate of temperature change satisfy the second thermal runaway condition, the controller is specifically configured as follows: The temperature value is determined to be greater than or equal to a first temperature threshold and less than a second temperature threshold, and the temperature change rate is greater than or equal to a first preset rate and less than a second preset rate.

7. The battery pack thermal runaway protection system according to claim 5 or 6, characterized in that, In the second state, the first electromagnetic shut-off valve is open, the second electromagnetic shut-off valve is open, the first valve port of the three-way valve and the second valve port of the three-way valve are closed, the first valve port of the three-way valve and the third valve port of the three-way valve are open, the first electronic expansion valve is closed, the second electronic expansion valve is open, and the third electronic expansion valve is open.

8. The battery pack thermal runaway protection system according to claim 1, characterized in that, For determining that the temperature value satisfies the third thermal runaway condition, the controller is specifically configured as follows: The temperature value is determined to be greater than or equal to the second temperature threshold and less than the third temperature threshold.

9. The battery pack thermal runaway protection system according to claim 1 or 8, characterized in that, In the third state, the first electromagnetic shut-off valve is on, the second electromagnetic shut-off valve is off, the first electronic expansion valve is off, and the third electronic expansion valve is on.

10. The battery pack thermal runaway protection system according to claim 1, characterized in that, The controller is further specifically configured as follows: Obtain the condenser temperature and the ambient temperature; The temperature difference is obtained based on the condenser temperature and the ambient temperature. When the refrigeration device has been running for a preset duration, the switching state of the control valve group and the working state of the refrigeration device are controlled according to the temperature difference.

11. The battery pack thermal runaway protection system according to claim 10, characterized in that, The battery pack thermal runaway protection system also includes a low-voltage battery. Specifically, the controller is configured to control the switching state of the control valve group and the operating state of the refrigeration device based on the temperature difference. If the temperature difference is determined to be lower than the preset temperature difference threshold, the switching state of the control valve group is controlled to the fourth state, and the refrigeration device is controlled to stop operating. Control the battery pack to stop supplying power, and control the low-voltage battery to start supplying power.

12. The battery pack thermal runaway protection system according to claim 11, characterized in that, The first valve port and the second valve port of the three-way valve are connected to the second cooling circuit, and the first valve port and the third valve port of the three-way valve are connected to the first cooling circuit. In the fourth state, the first electromagnetic shut-off valve is shut off, the first valve port of the three-way valve and the second valve port of the three-way valve are cut off, the first valve port of the three-way valve and the third valve port of the three-way valve are connected, and the third electronic expansion valve is shut off.

13. The battery pack thermal runaway protection system according to claim 11, characterized in that, After the battery pack stops supplying power, the controller is further configured to: If the rate of temperature change is determined to meet the fourth thermal runaway condition, the first liquid storage tank is opened and the switching state of the control valve group is set to the fifth state to dissipate heat from the battery pack.

14. The battery pack thermal runaway protection system according to claim 13, characterized in that, To determine that the rate of temperature change satisfies the fourth thermal runaway condition, the controller is specifically configured as follows: It is determined that the rate of temperature change is higher than the second preset rate.

15. The battery pack thermal runaway protection system according to claim 13 or 14, characterized in that, In the fifth state, the first electromagnetic shut-off valve is closed, the second electromagnetic shut-off valve is open, the first valve port of the three-way valve and the second valve port of the three-way valve are closed, the first valve port of the three-way valve and the third valve port of the three-way valve are open, the first electronic expansion valve is closed, the second electronic expansion valve is open, the third electronic expansion valve is closed, and the pressure relief solenoid valve is open.

16. The battery pack thermal runaway protection system according to claim 15, characterized in that, To determine that the rate of temperature change satisfies the fourth thermal runaway condition, and to control the opening of the first liquid storage tank and the switching state of the control valve group to the fifth state, the controller is specifically configured as follows: When the rate of temperature change is determined to meet the fourth thermal runaway condition, the refrigerant temperature value in front of the battery cooling plate and the current temperature value of the battery cooling plate are obtained. If the refrigerant temperature is determined to be lower than the current temperature, then the first liquid storage tank is opened and the control valve group is switched to the fifth state.

17. The battery pack thermal runaway protection system according to claim 13 or 16, characterized in that, The controller is further specifically configured as follows: Obtain the current pressure value within the battery cooling plate; If the current pressure value is determined to be lower than the first preset pressure value, then the switching state of the control valve group is controlled to the sixth state.

18. The battery pack thermal runaway protection system according to claim 17, characterized in that, In the sixth state, the second solenoid shut-off valve and the pressure relief solenoid valve are both shut off.

19. The battery pack thermal runaway protection system according to claim 16, characterized in that, The controller is further specifically configured as follows: If the refrigerant temperature is determined to be higher than the current temperature, then the control valve assembly is switched to the seventh state.

20. The battery pack thermal runaway protection system according to claim 19, characterized in that, In the seventh state, the second electromagnetic shut-off valve is shut off.

21. The battery pack thermal runaway protection system according to claim 19 or 20, characterized in that, After controlling the switching state of the control valve group to the seventh state, the controller is further specifically configured as follows: Obtain the current pressure value within the battery cooling plate; If the current pressure value is determined to be lower than the second preset pressure value, then the first liquid storage tank is opened and the control valve group is switched to the fifth state.

22. The battery pack thermal runaway protection system according to claim 1, characterized in that, The battery pack thermal runaway protection system also includes a second liquid storage tank containing coolant. The refrigerant circulation pipeline also includes a third cooling circuit, with the second liquid storage tank located on the third cooling circuit and connected to the third cooling circuit.

23. The battery pack thermal runaway protection system according to claim 22, characterized in that, The controller is specifically configured to control the on / off state of the control valve assembly and the operating state of the refrigeration unit based on the temperature value and / or the rate of temperature change. Once the temperature value is determined to meet the fifth thermal runaway condition, the second liquid storage tank is opened and the switching state of the control valve group is set to the eighth state to activate the third cooling circuit.

24. The battery pack thermal runaway protection system according to claim 23, characterized in that, For determining that the temperature value satisfies the fifth thermal runaway condition, the controller is specifically configured as follows: The temperature value is determined to be greater than or equal to the third temperature threshold.

25. The battery pack thermal runaway protection system according to claim 23, characterized in that, The control valve assembly also includes: The third electromagnetic shut-off valve, wherein the first valve port of the third electromagnetic shut-off valve is connected to the second liquid storage tank, and the second valve port of the third electromagnetic shut-off valve is connected to the first valve port of the second electronic expansion valve; In the eighth state, the first electromagnetic shut-off valve is open, the second electromagnetic shut-off valve is open, the first valve port of the three-way valve and the second valve port of the three-way valve are connected, the first valve port of the three-way valve and the third valve port of the three-way valve are closed, the first electronic expansion valve is open, the second electronic expansion valve is open, the third electronic expansion valve is closed, the third electromagnetic shut-off valve is open, and the pressure relief solenoid valve is open.

26. The battery pack thermal runaway protection system according to claim 25, characterized in that, Upon determining that the temperature value satisfies the fifth thermal runaway condition, the controller is specifically configured to open the second liquid storage tank and set the control valve assembly to the eighth state, and to control the on / off state of the control valve group to the eighth state. When the temperature value is determined to meet the fifth thermal runaway condition, the refrigerant temperature value in front of the battery cooling plate and the current temperature value of the battery cooling plate are obtained. If the refrigerant temperature is determined to be lower than the current temperature, then the second liquid storage tank is opened and the control valve group is switched to the eighth state.

27. The battery pack thermal runaway protection system according to claim 26, characterized in that, The controller is further specifically configured as follows: Obtain the current pressure value within the battery cooling plate; If the current pressure value is determined to be lower than the first preset pressure value, then the switching state of the control valve group is controlled to the ninth state.

28. The battery pack thermal runaway protection system according to claim 27, characterized in that, In the ninth state, the third solenoid shut-off valve and the pressure relief solenoid valve are both shut off.

29. The battery pack thermal runaway protection system according to claim 26, characterized in that, The controller is further specifically configured as follows: If the refrigerant temperature is determined to be higher than the current temperature, then the control valve group is switched to the tenth state.

30. The battery pack thermal runaway protection system according to claim 29, characterized in that, In the tenth state, the third electromagnetic shut-off valve is shut off.

31. The battery pack thermal runaway protection system according to claim 29 or 30, characterized in that, After controlling the switching state of the control valve group to the tenth state, the controller is further specifically configured as follows: Obtain the current pressure value within the battery cooling plate; If the current pressure value is determined to be lower than the second preset pressure value, then the second liquid storage tank is opened and the control valve group is switched to the eighth state.

32. A vehicle, characterized in that, include: Battery pack; The battery pack thermal runaway protection system according to any one of claims 1-31, wherein the battery pack thermal runaway protection system is connected to the battery pack to provide thermal runaway protection for the battery pack.

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