Abstract
Secondary batteries have been widely studied due to their highly efficient electrical and chemical energy-converting performance. Further improvement of these batteries is expected to meet the growing demands of the economy and technology. Various advanced characterization techniques have been applied in secondary batteries to gain a deeper understanding of electrochemical evolution and detection in the discharge/charge process. The ultrasound technique, with its high sensitivity, low cost and real-time detection ability, shows great potential for the characterization of secondary batteries. In this chapter, we introduce the fundamental principles of the ultrasound technique and summarize its applications in secondary batteries.