Battery Thermal Management System (BTMS)
Battery thermal management system (BTMS) is the hardware and control system that heats, cools, and balances temperature across an EV battery pack.
What it controls
Cell resistance, charging capability, available power, efficiency, and ageing all change with temperature. A BTMS uses temperature measurements together with pumps, valves, fans, heaters, cooling plates, refrigerant circuits, or other hardware selected for the pack design. It can also prepare the battery before fast charging or demanding driving.
The BMS may request heating or cooling, while the BTMS hardware performs the physical temperature control.
BTMS describes normal operating-temperature control. It is not the same as containing Thermal Runaway after self-sustaining reactions have begun inside a failed cell; that requires separate cell- and pack-level safety measures.
For system architectures, preconditioning strategies, and trade-offs, see Battery Thermal Management.