A review of air-cooling battery thermal management systems for electric and hybrid electric vehicles

Battery Thermal Management System (BTMS) is critical to the battery performance, which is important to the overall performance of the powertrain system of Electric Vehicles (EVs) and Hybrid Electric vehicles (HEVs). Due to its compact structure, high reliability, and safety characteristics, the air-cooling BTMS has been widely used in EVs and HEVs industry with cost-reduction demand or under severe and unpredictable working environments. This paper first reviews battery heat generation mechanisms and their impact (e.g. thermal aging, thermal runaway and fire accident) on the powertrain system in EVs and HEVs. Then the basic air-cooling BTMS design is reviewed, and a variety of novel design improvements is evaluated to explore the benefits and challenges of the use of the air-cooling BTMS. It is found that with the help of advanced computational numerical simulations and sophisticated experiments, the air-cooling efficiency is greatly improved by introducing new concepts of battery packs, innovative designs of the cooling channel, and novel thermally conductive materials. Based on the review, this paper suggests future research directions and potential solutions in a discussion for further development of the air-cooling BTMS in the EV and HEV industry.