Innovative Module Design with Actice and Passive Cooling of Traction Batteries

The shift toward electromobility requires innovative solutions for battery design and the associated peripherals in order to increase the efficiency and safety of electric vehicles and increase sustainability. This major challenge was taken up by a consortium of five Fraunhofer institutes as part of a research project. The goal was to develop new designs and manufacturing technologies for e-mobility applications, which would then be implemented in a resource-efficient battery module demonstrator. This module demonstrator (Fig. 1) initially consists of two identical cast aluminum half-shells with integrated copper channels for active cooling of the battery cells. These halves are bonded together via fire retardent fiber composite side panels (right, left and back). The adhesive used is thermally releasable, allowing easier disassembly. The module lid is attached to the front face and consists of a metal foam sandwich, which is infiltrated with phase change material (PCM). The PCM serves as a passive cooling system for the power electronics located on the backside of the lid, enabling thermal load peak flattening and increased temperature homogeneity within the power electronics. The heat stored in the PCM can be released to the environment or be removed via the active cooling system subsequent to the peak loads. The overall cooling management of the module thus also allows very heat-intensive charge and discharge cycles. Thin fire protection materials are located between the cells to prevent thermal propagation in the event of a thermal runaway of a cell. Several modules can be interconnected to form a stable unit that can be expanded as required.