Li-Ion batteries (LIB) are electro-chemical energy storage systems employed to match the electricity production and demand in stationary and mobile applications . They play a major role in distributed renewable energy systems and electric vehicles (EVs). Their success is mainly due to their higher energy and power densities and moderate ageing compared to other electro-chemistries [1–3]. When employed in EVs, however, LIB generate heat at high charge and discharge rates which leads to a consistent difference in temperature between LIB and the surrounding environment and temperature disuniformity within the LIB pack. As LIB performance and degradation are highly dependent on their operating temperatures, this leads to a decrease in operating life and higher costs [1,2,4]. Hence, LIB should be maintained at a constant uniform temperature in the range of 25°C-35°C . Effective thermal management, providing sufficient cell isothermalisation is therefore key to extending the life and economic viability of LIB.
Among the several Thermal Management Systems (TMS), phase change materials (PCM), mainly solid-liquid, are indicated as an effective TMS characterised by low costs, compactness, high efficiency, design simplicity. However, when LIB are exposed to extreme electrical regimes, PCMs cannot recover their latent heat due to their low thermal conductivity. This issue can be solved by combining PCM with active air/liquid cooling and/or heat pipes, i.e. hybrid TMS [1,5].
The aim of this project is to develop an integrated modular TMS for EV LIB packs by using numerical (CFD) and experimental approach. The LIB will demonstrate significantly reduced degradation rates and benefit EV industries, including local SME e.g. Equipmake Ltd. Key project objectives will include:
- Electrical and thermal characterisation of Li-Ion batteries for different geometries and chemistries
- Design of a hybrid TMS based on PCM
- Development of a prototype that can be scaled for applications in EVs