Electric vehicle battery cooling using excess cabin air conditioning capacity
A battery thermal management system includes a passenger cabin air-conditioning refrigerant loop including at least one evaporator in fluid communication with a chiller and a battery pack coolant loop in fluid communication with the chiller. A controller is configured to determine whether a temperature of the at least one evaporator falls within a predetermined temperature range, and if so to cause a valve to bypass a refrigerant from the air-conditioning refrigerant loop to the chiller. Evaporator temperature is determined by providing at least one evaporator temperature sensor.
1. A battery thermal management system, comprising:
a passenger cabin air-conditioning refrigerant loop comprising at least one evaporator in fluid communication with a chiller;
a battery pack coolant loop in fluid communication with the chiller; and
a controller configured to determine whether a battery pack temperature has reached or exceeded a predetermined upper limit, whether the at least one evaporator is operating, and whether a temperature of the at least one evaporator falls within a predetermined temperature range, and only when the above conditions have been met to cause a valve to bypass a refrigerant from the air-conditioning refrigerant loop to the chiller.
2. The battery thermal management system of claim 1 , wherein the valve is a thermal expansion valve (TXV) which controls introduction of the refrigerant into the chiller.
3. An electric vehicle including the battery thermal management system of claim 1 .
4. The battery thermal management system of claim 1 , further including at least one evaporator temperature sensor.
5. The battery thermal management system of claim 2 , further including at least one battery pack temperature sensor.
6. The battery thermal management system of claim 1 , wherein the passenger cabin air-conditioning refrigerant loop further comprises a compressor.
7. The battery thermal management system of claim 6 , wherein the controller is further configured to prevent the compressor from operating above a predetermined maximum operating pressure.
8. In an electric vehicle, a method for battery pack thermal management, comprising:
configuring a controller to determine whether a temperature of at least one evaporator of a passenger cabin air-conditioning refrigerant loop falls within a predetermined temperature range and whether a battery pack temperature has exceeded a predetermined upper limit; and
configuring the controller to, only when the above conditions are met, cause a valve to introduce a refrigerant from the passenger cabin air-conditioning refrigerant loop into a chiller in fluid communication with both the passenger cabin air-conditioning refrigerant loop and a battery pack coolant loop to transfer excess cooling capacity from the passenger cabin air-conditioning refrigerant loop to the battery pack coolant loop.
9. The method of claim 8 , including providing a thermal expansion valve (TXV) to control introduction of the refrigerant into the chiller.
10. The method of claim 8 , including determining a temperature of the at least one evaporator by at least one evaporator temperature sensor.
11. The method of claim 10 , including determining the battery pack temperature by at least one battery pack temperature sensor.
12. The method of claim 8 , further including providing the passenger cabin air-conditioning refrigerant loop with a compressor.
13. The method of claim 12 , further including configuring the controller to prevent the compressor from operating above a predetermined maximum operating pressure.
14. A battery thermal management system, comprising:
a passenger cabin air-conditioning refrigerant loop comprising at least one evaporator in fluid communication with a chiller;
a battery pack coolant loop in fluid communication with the chiller; and
a controller configured to determine whether a temperature of the at least one evaporator falls within a predetermined temperature range and whether a battery pack temperature has reached or exceeded a predetermined upper limit, and, only when both conditions are met, on request to cause a valve to introduce a refrigerant from the air-conditioning refrigerant loop into the chiller to transfer excess cooling capacity from the passenger cabin air-conditioning refrigerant loop to the battery pack coolant loop.
15. The battery thermal management system of claim 14 , further including at least one evaporator temperature sensor.
16. The battery thermal management system of claim 14 , wherein the valve is a thermal expansion valve (TXV) which controls introduction of the refrigerant into the chiller.
17. The battery thermal management system of claim 14 , further including at least one battery pack temperature sensor.