Where is the car battery safety valve?

On the battery cover. On the car, there is a one-way exhaust valve (also called safety valve) on the battery cover. The function of this valve is that when the gas inside the battery exceeds a certain value (usually expressed by the air pressure value), that is, when the air pressure inside the battery rises to a certain value, the exhaust valve automatically opens to discharge the gas, and then automatically closes the valve to prevent air from entering the battery. Battery is a kind of battery, also called battery, which refers to the battery that can continue to be used after discharge and charging, including lead battery, nickel-iron battery and nickel-cadmium battery. The working principle is to convert chemical energy into electrical energy.