Advanced Thermal Management Materials and Strategies for Packaging High Rate Cylindrical Cells and Battery Packs

H. Yang, P.S. Dimick, B.J. Tatarchuk
IntraMicron Inc., US

Keywords: battery, battery pack, microfibrous materials, thermal management, heat transfer, phase changement materials

Summary:

IntraMicron’s Enhanced Battery Pack (IEBP), is a synergistic combination of adaptable active & passive cooling structures to enable rapid charge/discharges of energy storage devices. IEBP consists of two key components: a porous network of sintered copper fibers (i.e., MFM, microfibrous media) to improve interfacial heat transfer between the batteries and the cooling structures (e.g. cooling water tubes and phase change materials, PCM) and a PCM wicked within the high internal porosity of the MFM (i.e., MFM+PCM) as an embedded passive, high-heat-capacity cooling agent allowing selectable peak battery temperature regulation. IEBP demonstrated a high thermal conductivity (25 W/m-K) and a high heat transfer coefficient (1300-2100 W/m2-K) on the cell surface. IEBP also has the improved ability of regulating the battery surface temperatures in the melting temperature range of the chosen PCM. With these attributes, IEBP enabled a collection of tightly packaged 26650 Li-ion cells (cell volume fraction =0.51) to safely operate at battery surface temperature less than 50°C during high-rate charge (4C) and discharge (12-20C) cycling at an ambient temperature of 60°C. For the same reason, IEBP also reduces or eliminates system cool-down time, enhances safety/reliability, and improves the cells’ cycle life, performance, and survivability in abusive environments.