The temperature distribution in a battery is critical to the performance of its operation, efficiency, charge acceptance, power and energy density, reliability and lifetime. The thermal management of a battery is extremely complex. Since the cells are heated during idling and must be cooled during operation, the system consists of temporal and spatial heat sources and sinks. Batteries equipped with thermocouples do not show all possible hot spots. 

Here, CFD analysis helps to understand the behavior of the temperature distribution in the overall system. This process is the basis for an optimization of the system.

The following picture shows the CFD setup:

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The following pictures display the temperature distribution. The air flows into the battery, emanating from the front. It heats up within a very short period of time as soon as it flows along the hot cells. The cross-section through the cells shows that rear cells are insufficiently cooled. The corners of the box show high temperatures. Furthermore, the investigation has shown that the incoming air is heated by the outgoing hot air even before it enters the cells, as the inlet and outlet are arranged on the front panel.

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The following figure shows the streamlines of the cooling air and the temperature distribution in the horizontal section plane.

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The optimization steps led to a more homogeneous temperature distribution and therefore to longer service life and higher power and energy density.