A Polymer-based Thermal Energy Storage Composite for Temperature Control of Sensors and Electronics

A novel lamination that consists of aluminum heat spreader plates interspersed with a polymer-based thermal energy storage composite is described. The composite consists of a thermoplastic matrix that encapsulates paraffin such that it is immobilized when in the liquid phase. As a consequence, the thermal energy storage/release process is independent of g-loading or orientation. Composites with paraffin mass fractions as high as 80% have been formulated. When combined with a suitably designed heat input/spreader mechanism, the resulting lamination is a responsive and compact thermal energy storage element. The fabrication methodology and thermal characteristics of the polymer composite are described. Hermeticity testing at elevated temperatures, and durability testing of the composite and its bond to aluminum heat spreader plates in repeated thermal cycling across the paraffin phase transition is documented. A thermal model of the heat storage/release process is developed and used to optimize the design of plate-like laminations. Prototype TES-systems are fabricated and tested to benchmark the thermal performance model.