Nowadays, almost all new energy electric vehicle battery packs are equipped with explosion-proof and waterproof breathable valves. These valves are generally designed to ensure good waterproof and breathable performance of the battery pack, and also have a pressure relief function under certain pressure. So, what is the working principle of the explosion-proof and waterproof breathable valve for battery packs?

What is the working principle of the explosion-proof and waterproof vent valve in the battery pack?
The material that serves as the waterproof and breathable component of the explosion-proof and waterproof breathable valve in the battery pack is expanded polytetrafluoroethylene (E-PTFE) microporous membrane. The raw material of eptfe waterproof breathable membrane can effectively achieve waterproof and breathable functions because its micropore size is much larger than the gas molecules in the air, yet much smaller than particles such as water and dust. It can also achieve dynamic pressure balance inside and outside through gas exchange. Under normal pressure conditions, the explosion-proof valve in the battery pack is no different from an ordinary waterproof breathable valve. However, in case of high pressure, it will be in an explosion-proof pressure relief state, and the internal pressure will push open the built-in piston on the explosion-proof valve of the battery pack, allowing the interior to directly communicate with the outside. This allows for rapid gas discharge and pressure reduction, thus achieving explosion-proof function.