Interest in electric vehicles (EVs), including hybrid and plug-in vehicles, has increased in recent years. Li-ion batteries are the main type of battery used in these vehicles. The thermal management of Li-ion batteries has a significant impact on their performance, lifetime and safety. While the overall operating temperature of a vehicle is typically -45°C to 55°C, the operating range of a Li-ion battery is limited to 20°C to 40°C. This clearly demonstrates the need for an effective battery thermal management system. In this project, we propose the integration of polymeric heat pipes with phase change materials (PCMs) as a lightweight, low cost and efficient thermal management system for Li-ion batteries in electric vehicles. The main objective of this project is to fabricate and test a polymeric heat pipe and evaluate its performance under real operating conditions in a battery module. This new technology can be potentially 80% cheaper and 90% lighter than the metallic heat exchangers currently used in electric vehicles. This work is being done in collaboration with industrial partners with a view to commercialisation.