The design of the over-temperature protection system for lithium battery packs needs to comprehensively consider multiple aspects such as temperature monitoring, heat dissipation, heat-resistant packaging structure, and dynamic management of the battery management system (BMS). The following are the specific design ideas:

Temperature monitoring

The temperature sensor can be installed at key positions in the battery pack, such as the surface of the battery cells and the casing of the battery pack. Once the temperature exceeds the predetermined threshold, the sensor will send out an alarm signal to notify the system that an overheating phenomenon has occurred. For example, the lithium-ion battery charging controller designed based on the STM32 single-chip microcomputer detects the temperature of the lithium battery through the DS18B20 temperature sensor. When the detected temperature exceeds 40℃, the relay will disconnect to ensure safety.

Heat dissipation design

Ventilation system: Install fans or air flow guiding devices on the outer casing of the battery pack. By controlling parameters such as the start and stop of the fans and their rotational speed, the internal temperature of the battery pack can be effectively reduced.

Heat dissipation components: Incorporating heat sinks, heat dissipation tubes and other heat dissipation components in the design of battery packs can enhance the heat dissipation effect.

Heat-resistant packaging structure design

Adding high-temperature resistant materials such as ceramics and metal alloys to the outer shell material of the battery pack can effectively slow down the speed of overheating transmission and protect the internal structure and materials of the battery from damage.

Dynamic management of Battery Management System (BMS)

By monitoring parameters such as the temperature and current of the battery pack, BMS can promptly determine whether the battery is overheating and conduct dynamic management of the battery. When the temperature exceeds the safety threshold, the BMS can automatically control the charging and discharging process of the battery, reduce the internal temperature of the battery, and maintain the safe operating state of the battery pack. For example, the lithium battery management system with the AT89C51 single-chip microcomputer as the core uses the 18B20 chip for temperature detection. When the temperature is higher than the set value, an alarm signal will be issued and processed by the processor.