Research Projects

For EVs to successfully replace petrol/diesel vehicles, the performance of Li-ion power batteries is critical that in turn depends mainly on temperature. Hence a robust cooling system is key component of Li-ion battery systems. Battery thermal management systems can be either internal or external. Internal system refers to any change of the battery cell or the internal resistance. External system implies air or liquid cooling external to the cell. The external system can be further divided into active, passive and hybrid. Active systems require electrical power like air-based, liquid-based and thermoelectric. Passive systems don’t require any electrical power like phase change material (PCM) and heat pipe. Hybrid (combination of active and passive systems) system gives the best performance. The problem statement of this proposal is to design a techno-economic optimized hybrid cooling system for Li-ion battery packs. PCM system is better than air-based and liquid-based systems. Thermal conductivity of PCMs can be increased by adding expanded graphite, carbon fibres, graphene, metal mesh, metal foam or nanoparticles inside PCM and enhancing performance by adding fins. Copper-water combination as a working fluid for heat pipes have also been studied extensively. Three hybrid cooling system – PCM/air, PCM/liquid and PCM/heat pipe have been studied. This proposal has the following objectives: 1. PCM system will be optimized for quantity of PCM & additives (thermal conductivity Vs latent heat), fins (surface area Vs space Vs convection) 2. Heat pipe system will be optimized for evaporator, condenser, and working fluids 3. Flow & thermal optimization of air flow or liquid based cooling system

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