Thermal Characterization of a Li-ion Battery Module Cooled through Aluminum Heat-Sink Plates

The temperature distribution is studied theoretically in a battery module stacked with 12 high-power Li-ion pouch cells. The module is cooled indirectly with ambient air through aluminum heat-sink plates or cooling plates sandwiched between each pair of cells in the module. Each of the cooling plates has an extended cooling fin exposed in the cooling air channel. The cell temperatures can be controlled by changing the air temperature and/or the heat transfer coefficient on the cooling fin surfaces by regulating the air flow rate. It is found that due to the high thermal conductivity and thermal diffusivity of the cooling plates, heat transfer of the cooling plate governs the cell temperature distribution by spreading the cell heat over the entire cell surface. Influence of thermal from the cooling fins is also simulated. It is observed that cell temperature gradients are strongly influenced by the heat transfer resistance of the cooling plate and changes in the cooling air temperature shift the cell temperatures up or down without impacting the cell temperature distribution. It is shown in this study that indirect air cooling has a lower differential cell temperature and a more uniform cell temperature distribution in comparison to those in direct air cooling.