Tech Briefs

With further development, dual functionality is expected to translate to weight efficiency.

A continuing program of research and development is devoted to the design, fabrication, and testing of polymeric composite- material devices that are multifunctional in the sense that they both store electrochemical energy and bear mechanical loads. It is anticipated that if designed to exhibit sufficient structural and energy efficiencies, these devices could enable significant reductions in the weights of systems in which they could be used, by supplanting electrically inert structural components and conventional batteries while providing supplementary power for lightload applications.

Not only can a device of this type be regarded in its entirety as both a structural component and an electrochemical cell or battery, in addition, each component (the electrodes and electrolyte) of the device is designed to have a desired combination of electrochemical properties and mechanical strength. In the fabrication of the device, these components are integrated by use of costeffective molding processes and other processes that are commonly used in the manufacture of composite-material objects and that can be scaled up to mass production.

The Layers and Sublayers of structural polymeric composite batteries are optimized to perform well as both electrochemical and structural components.
The figure presents a partly schematic cross-section of a representative basic structural polymeric composite battery comprising multiple cell layers. Each cell layer consists of an anode sublayer made of a carbon-fiber fabric, a separator sublayer made of a glass fabric, a cathode sublayer in the form of a metal mesh coated with a cathode material, and a structural solid polymer electrolyte that fills the spaces between the aforementioned sublayers, binding all sublayers and layers together. The cathode and anode sublayers both bear mechanical loads and act as electriccurrent collectors. The separator sublayer provides additional structural support while ensuring electronic isolation of the electrode sublayers. The polymer electrolyte transfers mechanical loads to and from the other components and conducts ions between electrodes.