Principle of electric vehicle charging system

The vehicle-mounted power battery provides energy, and the motor provides power to drive. The electric vehicle consumes the energy of the battery, which needs to be replenished after consumption, by transferring the electric energy in the power grid or other energy storage equipment to the battery of the vehicle.

The electric energy in the power grid or energy storage equipment needs to be converted by charging equipment to match the technical characteristics of the power battery of electric vehicles, so as to complete charging. In the conversion process of charging equipment, it is necessary to negotiate with the BMS (Battery Management System) on the electric vehicle to complete the charging with appropriate voltage and current, and during the charging process, the charging current will decrease with the charging process, and the initial high-current charging can be faster, and the later low-current charging can be slower. AC slow charging: AC charging pile has no power conversion module, so it does not carry out AC -DC conversion, outputs AC power, connects it to the car, converts it into DC power through the charger on the car, and then inputs it into the battery. The charging power depends on the power of the car charger. At present, the mainstream models of car chargers are 2Kw, 3.3Kw and 6.6Kw. Generally speaking, charging is slow. Generally, hybrid vehicles need to be fully charged for 4-6 hours, while pure electric vehicles need to be fully charged for more than 8 hours, and the charging rate is basically 0. Below 5C. DC fast charging: DC charging pile has a built-in power conversion module, which can convert the AC power of the power grid into DC power, and directly connect it to the battery in the car without the need for on-board charger conversion. The charging power depends on the battery management system and the output power of the charging pile, whichever is smaller.