Cavity structure-based active controllable thermal switch for battery thermal management.

Batteries may degrade fast at extreme temperatures, posing a challenge in meeting the dual requirements of heat preservation at low temperatures and efficient cooling at high temperatures. To address this issue, we propose a cavity structure-based active controllable thermal switch. It has a potential switch ratio (SR) of approximately 300, with an experimental SR of 15.4. Furthermore, the thermal resistance can be actively controlled. The "OFF State" of the thermal switch increases energy discharge at low temperatures. Pre-heating with the "OFF State" consumes only 60% of the energy required in the "ON State". By employing the "ON State" at an ambient temperature of 20°C, the battery temperature can be maintained below 35°C. And the "ON + State" keeps the maximum battery temperature remaining below 42°C under extreme conditions. These findings demonstrate that the implementation of the proposed thermal switch enhances the usability of batteries in extreme environments.