Dual-Protection Mechanics of Battery Pack Explosion-Proof Pressure Relief Valves
To suppress thermal runaway propagation, the explosion-proof pressure relief valve provides a vital dual-layer defense mechanism for energy storage and EV battery packs:
Phase 1: Normal Ventilation & Equilibrium (Nominal State)
Structure: Designed as a normally closed (NC) component, the valve contains a specialized venting matrix (often an ePTFE membrane).
Function: It continuously balances slow pressure and temperature fluctuations inside the enclosure caused by diurnal cycles or cell cycling. This ensures bi-directional breathing while maintaining strict waterproof and dustproof seals to prevent external moisture ingress.
Phase 2: Emergency Rapid Depressurization (Thermal Runaway State)
Trigger: When a cell undergoes thermal runaway, it releases massive volumes of gas, creating a severe internal pressure spike.
Mechanism: Once the internal pressure hits the designated cracking threshold, the internal gas pressure instantly overcomes the mechanical spring preload.
Result: The piston rod shifts, forcing the primary relief channel to open wide. This enables high-volume, rapid gas evacuation, instantly lowering pack pressure and preventing enclosure failure.
Installation Requirements:
Keep away from heat sources, the passenger cabin, and electrical connectors; ensure ample pressure relief space.
Strictly control installation surface flatness and tightening torque to prevent water ingress and gas leakage.
Venting Design:
Utilize a two-stage venting and diversion design (cell and pack levels) to rapidly discharge high-temperature conductive ejecta, avoiding accumulation and secondary short circuits.
