Design of lithium battery pack fault diagnosis system based on two levels state machine

This paper discussed the design of a useful system, which is used for monitoring the status of lithium battery pack and diagnosing its fault. This system was implemented through creatively adopting two levels state machine. The faults that the power lithium battery pack may occur were used for defining the status of finite state machine. The two-stage state machine was used for recording and reporting all kinds of fault information, while the one-stage state machine was used for determining the final system output. This system communicated with PC through CAN, and provided a lot of important information for the battery management system. Experiments show that this system can judge fault type and fault level efficiently and accurately and it also can take protective measures timely, thus improves the reliability and security of power lithium battery pack.