Abstract: An experimental platform integrating constant-temperature environment simulation, charge-discharge control, and multi-parameter monitoring (temperature, voltage, gas concentration) was established. Normal charge-discharge and overcharge comparison tests were conducted under three environmental temperatures. The study found that during normal charge-discharge, the temperature change of the battery is dominated by the environmental temperature, with a slow temperature rise at low temperatures, a continuous temperature increase at high temperatures, and a stable temperature at room temperature. Under the overcharge condition, however, significant dangerous characteristics were observed: the battery temperature exceeded 100 °C in all three environmental temperatures, accompanied by the intense release of flammable gases such as hydrogen, VOCs, sulfur dioxide, and hydrogen sulfide, posing an explosion risk in a confined space, with the fastest temperature rise rate at 40 °C. Based on these findings, this paper proposes an intelligent thermal runaway early warning system: relying on the BMS master-slave architecture, it collects battery terminal voltage, multi-point temperatures, and hydrogen/VOCs gas concentrations in real time. The core early warning parameters include temperature thresholds, upper limits of temperature rise rate, and hydrogen concentration thresholds, and it integrates SOC/SOH algorithms to track the battery's health status. This system can respond to abnormal temperature rise and gas leakage within milliseconds, triggering protection mechanisms to prevent thermal runaway accidents.

Key words: lead-acid battery, thermal runaway, ambient temperature, early warning monitoring