Rechargeable energy storage system cooling

A control system for cooling a rechargeable energy storage system (RESS) of a vehicle, the control system comprising:

• a passive cooling system for cooling the RESS;
• an active cooling system for cooling the RESS;
• and
• a controller coupled to the passive cooling system and the active cooling system, the controller comprising:
• a plurality of sensors configured to:
• measure a first temperature of coolant fluid entering the RESS during operation of the passive cooling system;
• and
• measure a second temperature of coolant fluid exiting the RESS during operation of the passive cooling system;
• and
• a processor coupled to the plurality of sensors and configured to:
• determine a flow rate of the coolant fluid during operation of the passive cooling system;
• calculate a measure of heat transfer using the first temperature, the second temperature, and the flow rate;
• initiate cooling of the RESS using the passive cooling system if the measure of heat transfer is greater than a predetermined threshold;
• and
• initiate cooling of the RESS using the active cooling system if the measure of heat transfer is less than the predetermined threshold.

A method for cooling a rechargeable energy storage system (RESS) of a vehicle, the method comprising:

• measuring a first temperature of coolant fluid entering the RESS during operation of a passive cooling system for the RESS;
• measuring a second temperature of coolant fluid exiting the RESS during operation of the passive cooling system;
• calculating a measure of heat transfer using the first temperature, the second temperature, and a flow rate of the coolant fluid;
• initiate cooling of the RESS using the passive cooling system if the measure of heat transfer is greater than the predetermined threshold;
• and
• initiate cooling of the RESS using an active cooling system if the measure of heat transfer is less than the predetermined threshold.