Investigation of Electrical Insulation Options for Battery Cooling Plate Surfaces

Abstract

This thesis deals with an investigation of several insulation options for such cooling plates. Different insulation systems were evaluated based on electrical, mechanical, ther­ mal, chemical and manufacturing properties as well as cost factors. Of these, the electri­ cal properties were experimentally examined. The core of the thesis was the experimental determination of the insulation resistance and dielectric breakdown voltage of different coating systems. These coatings can be grouped into anodization, a ceramic coating, polymer powder coatings, liquid paints and insulating films. The electrical tests performed showed that anodization, the ceramic coating, some powder coating systems and a coating process named e-coat do not suffice with regard to the two quantities under consideration. They experience a failure mech­ anisms referred to as dielectric breakdown. On the other hand, a number of insulating films, a silicon-based conformal coating and a 150µm epoxy powder coating system were found to be suitable for use on battery cooling plates. An approximate cost comparison of these final three coating methods was done to complete the project . This showed that powder coating and liquid painting outweigh the film application by a factor of two, in terms of capital invest costs.