Abstract: The failure problems, associated with shortened cycle life, increased self-discharge rate, deteriorated power performance and ect., often occur in the application of lithium ion batteries. They may even lead to safety problems under harsh conditions. Lithium deposition is considered as one of the most important factors leading to these failures and even safety problems. Therefore, it is particularly important to analyze the formation and growth process of lithium dendrites. In this paper, the in-situ detection techniques of lithium deposition in lithium batteries are reviewed, including physical and electrochemical methods. Physical detection methods are systematically introduced, such as optical in-situ technology, in-situ X ray technology, in-situ nuclear magnetic resonance technology and in-situ neutron technology. The electrochemical methods include charge-discharge voltage curve method, Arrhenius method, internal resistance-capacity curve analysis method and capacity decay rate method. The principle, advantages, limitations, and corresponding special detection device of the above physical methods, and the principle and analysis method of electrochemical methods are introduced. Furthermoere, the problems of in-situ detection techniques are summarized and the future research direction is put forward.

Key words: Li-ion battery, failure problems, lithium dendrites, in situ detection