Improving battery performance: thermal management through highly thermally conductive casting resins

An efficient thermal management is of great importance to battery applications particularly in the field of e-mobility and power tools with ever more demanding requests. Battery lifetimecopaltech and capacity are dramatically influenced by thermal influences. In order to reduce the operating temperature and in turn increase battery service time and capacity batteries and battery packs can be encapsulated with thermally conductive potting resins. Through these thermally conductive potting resins the heat generated by the battery can be efficiently dissipated from the battery hence reducing the battery temperature.

For the large-scale application of such thermally conductive potting resins it is also important that they are compatible with current dispensing technology, especially regarding their viscosity to ensure processability. However, low viscosity is not only required to ensure smooth dispensing of the materials but also to ensure tight encapsulation of the battery with filling of even the narrowest gaps without air entrapments as these would significantly impact on the thermal conductivity, acting as a thermal insulator. Since thermal conductivity is normally achieved through fillers which in turn results in increased viscosity, the combination of high thermal conductivity and low viscosity poses a significant challenge.

Copaltec has developed polyurethane-based thermally conductive potting resins which combine specifically these two important characteristics: high thermal conductivity whilst maintaining relatively low viscosity and hence exhibit good flow behavior. In collaboration with external partners copaltec was able to cast battery packs and increase the operating time by 10% whilst also increasing the capacity by up to 30%. Through the efficient thermal management of the battery pack it was also possible to increase the service time of the battery pack significantly. It is especially noteworthy that these results were obtained with a casting resin with only moderate thermal conductivity but could be achieved by the superior attachment of the material to the battery pack resulting in a defect-free cast and hence effective heat dissipation. Through the combination of an innovative filler matrix with a highly optimized production process copaltec was even able to develop resins with up to 3.5 W/m*K whilst maintaining good processability.

Copaltec will be exhibiting at The Battery Show Europe 2019 at stand 1036.