Maintenance and repair of electric buses

Common faults of chargers and Dc/Dc converters include: input undervoltage/input overvoltage, output undervoltage/output overvoltage, output not connected to battery, over temperature, short circuit, and reverse polarity. It needs to be handled at a professional electric vehicle maintenance station and repaired or replaced as necessary.
The abnormal disconnection of the power battery may be due to: insulation detection circuit failure, requiring replacement of the Bms main control box; If the insulation impedance is too low, it is necessary to check the insulation status of the high-voltage wiring harness and the insulation status of the central control box; The power cable busbar is broken and needs to be replaced in a timely manner; If the high-voltage relay does not engage, it is necessary to replace it in a timely manner; The fuse is blown and needs to be replaced in a timely manner; Bms malfunction, need to replace the Bms main control box.
When the power battery cannot be disconnected normally, it may be necessary to replace the high-voltage relay due to its adhesion.
The voltage problems of individual batteries, such as high, low, and various imbalanced performances, may be caused by damage to the individual battery, or by loose or detached connection strips of the individual battery. If the battery cell is damaged, it needs to be repaired or replaced at the electric vehicle maintenance station. If there is a problem with the connection strip, it is necessary to tighten the connection between the cells in a timely manner.
Inspection for abnormal temperature of the battery pack: If the temperature of the battery pack is too high, it may be caused by a malfunction of the cooling fan or temperature sensor. The rear fan and temperature sensor of the vehicle should be checked and replaced in a timely manner; If the temperature of the battery pack is too low, it may be due to low ambient temperature or temperature sensor failure. To handle this, it is necessary to turn on the battery heating device for heating and check and replace the temperature sensor in a timely manner; When the temperature of the battery pack is uneven, it may be due to the looseness of the connecting air ducts between the battery boxes, and it is necessary to tighten the connecting air ducts in a timely manner.
Soc exception. When the Soc is too high or too low, it may be due to abnormal Soc display or the power battery being too full or too low. This requires timely inspection and replacement of the display screen or Bms main control box, timely inspection, and charging and discharging of the power battery.
The current display is abnormal, which may be caused by faults in the current sensor or display screen, as well as data sent by Bms. Timely inspection and maintenance are required for handling, and relevant accessories need to be replaced as needed.
The air conditioning is abnormal, mostly due to the inability of the high-voltage relay to engage. It can be handled by referring to the abnormal disconnection method of the power battery.
When the vehicle and its heating equipment cannot start normally, it may be caused by the inability of the high-voltage relay to engage, resulting in the Dc/Dc converter not working properly. The handling method should refer to the handling method for abnormal disconnection of the power battery