Several Analysis Based on Electric Vehicle Charging System

Ⅰ. The composition of charging system of electric vehicle

1. Structural composition

The charging system of pure electric vehicles is mainly composed of two parts: the charging facilities outside the car and the on-board charging. The device is mainly composed of straight and AC charging ports, on-board charger OBC, high-voltage junction box, high-voltage wiring harness, power battery, battery management system BMS and contactors.

2. Charging process

Electric vehicle charging methods can be divided into two types: DC charging and AC charging. The commonly used AC charging piles have a power of 3.5KW and 7KW, while the DC charging pile power is as high as 30KW-120KW. The charging processes of the two are also different.

The main positive, main and auxiliary relays are located in the power battery pack. Precharge contactor, direct and AC charging contactor, main contactor are located in the high-voltage electronic control assembly box, they are all controlled by BMS, when the vehicle is fast charging, the charging current flow path: charging pile → fast charging port → DC Charging contactor+→positive relay→power battery→negative contactor→DC charging contactor-→charging port→charging pile.

Slow charging charging current flow path: charging pile → slow charging port → vehicle charger OBC → fuse → positive contactor → power battery → negative contactor → OBC → slow charging port → charging pile.

Ⅱ. The charging gun electronic lock of the charging system of electric vehicle

Mechanical principle of electronic lock:

The charging electronic lock is a fortress that must be locked before charging in order to prevent the charging gun from accidentally loosening or falling off during the charging process, causing electric shock and hidden dangers to vehicle property safety.

The electronic lock of the charging system of electric vehicle is mainly composed of a lock tongue, a lock slot and a lock pin. When performing AC charging, the staff needs to press the button on the charging gun. The button and the lock tongue are mechanically linked. When the charging button is pressed, the lock tongue will be shifted upward to open, and the charging gun can be easily inserted into the slow charging port. The lock pin extends and presses the lock tongue. At this time, the charging gun is in a locked state. Only when the key unlock button is pressed or the mechanical unlock switch is pulled, the lock pin can be reset and the charging gun can be removed by pressing the button.