Weight Reduction in Lithium Ion Pouch Cell Automotive Battery Modules Through the Use of Flexible Graphite Thermal Management Materials

摘要

Flexible graphite has been used for thermal management in advanced consumer electronics and industrial applications for over fifteen years and has been a major contributor to the evolution of devices that are thin and lightweight. Applying flexible graphite as a thermal management material to xEV automotive battery applications results in modules that are lighter, more compact, and with higher energy density than with previously used methods and materials. In addition, non-flammable graphite has been shown to be highly effective in the prevention of propagation in the event of a cell failure. To spread the same amount of heat, graphite has approximately 45% of the thickness and 30% of the weight of aluminum. Graphite is highly orthotropic in terms of thermal conductivity. In the X-Y plane, graphite spreads heat at 400 W/m?K, while only 4 W/m?K through the Z-plane. Graphite is non-reactive to standard battery chemistries and is completely non-flammable. Graphite complies with the REACH, RoHS, and Lead Free standards and is a conflict-free mineral. These properties have allowed the creation of automotive lithium-ion pouch cell battery packs and modules with higher energy density than previously possible using common thermal management metals, such as aluminum.