Safety warning for lithium-ion batteries by module-space air-pressure variation under thermal runaway conditions

Lithium-ion batteries are widely used in scalable electrochemical energy-storage stations because of their excellent characteristics. However, safety issues seriously hinder their further development and promotion. This paper proposes a safety warning method based on module-space air-pressure variation to provide warnings for battery thermal runaway (TR). TR is induced by different battery faults (overcharge, overheat), and the air pressure in the module space varies during the battery venting process. To verify the effectiveness of the TR warning by air-pressure variation signal, experiments were conducted in sealed and ventilated modules. The air pressures of the sealed and ventilated module spaces for batteries under 13 A (1C) overcharge-induced TR conditions were 19.3 hPa and 3.05 hPa higher, respectively, than the corresponding air pressures under normal conditions. Under 6.5 A (0.5C) overcharge-induced TR conditions, the air pressure of the sealed module space increased by 14.43 hPa. Under overheat-induced TR conditions, the sealed module space air pressure increased by 6.52 hPa. Upon detecting an air-pressure variation signal, immediate measures such as charge stoppage effectively prevent the occurrence of battery TR. The average time interval between the warning signal and battery TR was 473 s. This research provides a new way to enhance the safety of lithium-ion battery energy-storage stations. • A novel method of applying module space air pressure variation signal to warn battery thermal runaway is proposed. • This method is based on the principle that the air pressure in module space varies after battery venting. • According to this method, the average time interval between the warning signal and thermal runaway was 473 seconds.