As one of the most crucial components in electric vehicles, power batteries generate abundant heat during charging and discharging processes. Thermal management system (TMS), which is designed to keep the battery cells within an optimum temperature range and to maintain an even temperature distribution from cell to cell, is vital for the high efficiency, long calendar life and reliable safety of these power batteries. With the desirable features of low system complexity, light weight, high energy efficiency and good battery thermal uniformity, thermal management using composite phase change materials (PCMs) has drawn great attention in the past fifteen years. In the hope of supplying helpful guidelines for the design of the PCM-based TMSs, this work begins with the summarization of the most commonly applied heat transfer enhancement methods (i.e., the use of thermally conductive particles, metal fin, expanded graphite matrix and metal foam) for PCMs by different researchers. Newly developed TMS configurations such as the multi-layer PCMs and sandwiched ones are also discussed in detail. In addition, the hybrid TMS combining PCM cooling with air or liquid cooling, and battery heating by these PCM-based TMSs under cold environment are also summarized. Based on the analysis of previous studies, several possible research topics on PCM cooling are finally proposed in the conclusion/summary part.