With the vigorous development of the new energy industry in recent years, power batteries will usher in a large-scale retirement tide. Echelon utilization of power batteries can not only maximize the value of batteries and reduce the life cycle cost of power batteries but also weaken the threat of retired power batteries to the environment and alleviate the problems of high cost and low income associated with traditional energy storage systems. The traditional screening technology for consistency in the capacity division and constant capacity has low efficiency and high cost, making it difficult to adapt to the screening needs of power battery consistency in multiple scenarios. Data analysis has yet to play an integral role in the screening process; thus, fast and efficient battery screening technology has become one of the critical technologies for the large-scale application of retired batteries. Additionally, the existing echelon utilization technology cannot solve the problems of poor consistency; moreover, the degradation of the reorganized battery cascade operation is fast and the aging pattern is difficult to predict, posing significant safety hazards. The echelon utilization of retired power batteries still needs to achieve breakthroughs associated with large-scale applications, such as consistency management, dynamic safety monitoring, and regulation. Although the demonstration application of echelon utilization battery energy storage systems achieved satisfactory results initially, it still faces technical challenges such as system safety and economy. This study summarizes the research status of key technologies, such as sorting, evaluation, screening, detection, recombination, balancing, and safety of retired power batteries, by exploring recent relevant literature. It characterizes the industrial policies and national industry standards related to the echelon utilization of retired power batteries, which is expected to provide a reference for the reasonable use of large-scale retired power batteries.

Keywords： electrochemical energy storage ; retired power battery ; echelon utilization ; echelon utilization standards