Control method and control device of battery system

The embodiment of the invention provides a control method and a control device of a battery system, the battery system comprises N battery branches connected in parallel, N is a positive integer greater than 1, and the control method comprises the following steps: under the condition that at least one battery branch in the N battery branches is abnormal in communication, determining the high-voltage state of each battery branch in the N battery branches; and performing power control on the battery system according to the high-voltage state of each battery branch. According to the control method and the control device provided by the embodiment of the invention, the safety of the battery system is improved.