Thermal management of lithium-ion batteries using phase change materials

Good battery thermal management systems (BTMSs) are essential for Li­ion batteries for safe, reliability and efficiency. A BTMS needs to ensure not only the temperature of all battery cells within a safe range, but also the maximum temperature difference between different cells within battery pack below 5 ℃. Conventional BTMSs such as active air cooling and liquid cooling require extra power and fail to cope with high density of heat generation. Passive BTMSs make use of latent heat of phase change materials (PCMs) to absorb the heat generated by batteries are proved to be an effective way to maintain the battery temperature within their safety range without the use of extra energy. If combined with expanded graphite or metal foams, thermal conductivity of PCMs could be improved significantly. This can minimize the battery pack temperature difference and achieve an uniform temperature difference between different cells. As it is relatively easy to make PCMs into different shapes, they can be applied to batteries of different shapes and battery systems with a variety of configurations.