The battery pack seawater immersion tester is mainly used for the battery to be connected to the vehicle wiring harness in the real vehicle assembly state, and then placed in 3.5% NaCl (mass fraction, simulating the seawater composition at room temperature) in the real vehicle assembly direction for 2H, and the water depth is enough to submerge the test. Subject, observe 2H. If the battery pack or system does not catch fire, it is qualified that it does not explode or catch fire.