Fault diagnosis method and device and vehicle

The invention provides a fault diagnosis method and device and a vehicle, and the method comprises the steps: controlling a negative contactor to be closed when the vehicle is powered on and no battery pack loop fault exists in the last power-on period; detecting a first current value flowing through the cathode contactor; according to the invention, data support is provided for fault positioning of the battery pack loop, extra high-voltage sampling is not needed to detect the voltage of the whole battery pack, the circuit structure is simple, fault detection of the battery pack is realized based on simple current detection, the diagnosis speed is high, and the detection accuracy is high. And the fault diagnosis requirement of battery pack power supply can be met. 本发明提出一种故障诊断方法及装置和车辆，方法包括：车辆上电且上一个上电周期不存在电池包回路故障时，控制负极接触器闭合；检测流经负极接触器的第一电流值；根据第一电流值对电池包回路进行故障诊断，本发明为电池包回路故障定位提供数据支持，无需额外的高压采样检测电池包整包电压，电路结构简单，基于简单的电流检测实现对电池包的故障检测，诊断速度快，可以满足电池包供电的故障诊断需求。