Detection method and detection device for branch states of battery system

A detection method and a detection device for branch states of a battery system are provided. A current on/off state of each branch is judged according to a first open circuit voltage of the corresponding branch and a second open circuit voltage corresponding to the battery system. Time for detecting and diagnosing each branch state can be reduced. It solves that the problem of longer time consumption and large error caused by the determination of the status of each branch through the change of the voltage of each branch in the prior art. A detection efficiency of branch states and an accuracy of detection results of branch states are both improved. The detection method is simple and quick to operate, and will not cause the complexity to increase rapidly as the number of branches increases. The detection method has good feasibility and practicability, and has a wide range of applications.