Bio-PCM passive cooling strategies in battery thermal management systems for sustainable transportation: A comprehensive assessment

The accelerating uptake of electric vehicles (EV) as an eco-friendly transport option has highlighted the importance of effective battery thermal management systems (BTMS) for achieving performance, safety and reliability. Phase change materials (PCMs) provide an efficient cooling approach for maintaining cell temperature and improving battery durability and performance. Bio-PCM-based formulations are especially advantageous in thermal energy systems, which improve temperature control, durability and safety. However, there remains a lack of specific systematic review that incorporates their thermo-physical properties, performance enhancement methods, and practical applications for designing thermally efficient passive BTMS in EVs. This review systematically evaluates related experimental and numerical studies published over the last decade through a comprehensive literature survey using major scientific databases and predefined structured keywords. A key novelty of this review is the exclusive focus on bio-PC-enabled passive BTMS and the critical correlation established between Bio-PCM characteristics, thermal enhancement strategies, thermo-electrical battery performance, and sustainability aspects. The findings show that Bio-PCM-based formulations can effectively regulate battery temperatures within safe operating limits, achieving peak temperature reductions of 6.30-20.02°C at a 2C discharge rate, while passive BTMS integrating Bio-PCMs with heat-pipes and fins demonstrates the greatest temperature mitigation among the reviewed configurations. It further examines the environmental impact, lifecycle assessment, thermo-economic feasibility, scalability, and technical challenges associated with Bio-PCM-based BTMS, providing insights into their practical implementation and future development for sustainable electric mobility. Overall, emerging Bio-PCM-based passive cooling strategies offer significant prospects for developing thermally efficient, cost-effective and environmentally sustainable BTMS for next-generation electric mobility.