Relays are electronic components consisting of electromagnets and switches that receive electrical signals to control other electrical energy. As a special relay, large capacity DC relay is mainly used for electric connection between battery and engine of hybrid vehicle and electric vehicle. It is different from the ordinary relay, which requires accurate control of the high current driving the car. At the same time, in order to prevent electric shock caused by accidents, it also needs to have the function of cutting off the powerful current instantaneously.