Abstract: Lithium-ion batteries, as complex electrochemical devices, face increasingly prominent fire safety risks. This study conducted overcharge-induced thermal runaway（TR） experiments on a 280 Ah lithium-ion phosphate battery module. By collecting and analyzing the developmental patterns of battery voltage, temperature/temperature rise, and characteristic gases at different stages of TR progression, we proposed a hierarchical early warning method for lithium-ion battery TR that integrates multi-feature signals of voltage, temperature, and gas. Based on the hierarchical warning results, a TR prevention and control strategy was developed from a practical engineering perspective, combining the battery management system (BMS) of electrochemical energy storage with fire protection systems. The strategy was validated through TR tests on both 280 Ah and 314 Ah energy storage battery units. Experimental results demonstrate that the proposed early warning and prevention method can issue alarm signals at least 3 min earlier than pressure relief valve activation and more than 15 min earlier than the onset of TR, while initiating corresponding protective and firefighting measures based on the risk severity of TR.

Key words: lithium-ion battery, thermal runaway, early warning, multi-parameter integration