Abstract: Under the mandatory requirement of service reliability, DC charging piles are generally difficult to disassemble and have poor recycling performance. Therefore, a method for identifying the key components of DC charging pile is proposed to screen out the components that have important impact on service reliability and have high reuse potential but are difficult to recycle, so that designers can refer to these core components to reasonably allocate design resources. In this method, failure mode effects and criticality analysis(FMECA) is introduced into the reliability evaluation of charging piles, and the evaluation system of reliability and reusability of charging piles is established from three perspectives of risk priority number (RPN), recovery difficulty and reuse potential. The quantitative index data is derived from the disassembly experimental data and fault data under the actual operating environment of the charging pile, while the qualitative index data obtained by the expert evaluation method is described by triangular fuzzy numbers and aggregated to improve the accuracy of the data. By analyzing the qualitative and quantitative data by the technique for order preference by similarity to an ideal solution (TOPSIS), the comprehensive ranking of reliability and reusability of components is realized. Finally, the method is applied to the 80 kW one-piece used a gun charging pile of state grid. The results of analysis indicate that the parts of charging gun, charging module, AC main contactor, charging control unit, display screen, charging main control module and incoming plastic shell circuit breaker need to be concerned in the future design process to effectively improve the reliability and recyclability of the DC charging pile.

Key words: DC charging pile, reliability, reusability, FMECA, TOPSIS