Electro-Mechanical Simulation of Multifunctional Composite Structural Batteries

Abstract

Multifunctional structural battery composites are able to store and deliver electrical energy while replacing or being integrated into the structure of the system to support operational loadings. These composites can be employed in a wide variety of systems including automobiles and aircraft to provide auxiliary electric charge while simultaneously reducing weight for extended range and efficiency. These efforts focused on investigating laminate mechanical properties, as well as preliminary coupled electrical-structural-thermal micromechanical analyses. Several carbon reinforcing materials and potential laminate orientations were analyzed through both FEM and analytical methods to determine laminate flexural properties. A simulated three point bend test was employed to determine the flexural stiffness and strength. The stiffnesses and strengths for the composite were determined using carbon fiber paper, AS4 unidirectional carbon fiber, P100 carbon fiber, and a carbon paper reinforcement with interstitial honeycomb core material. This honeycomb core was investigated as a means to assuage the tradeoff between mechanical and electrical properties of the structural battery constituent materials. Three coupled electrical-structural micromechanics models were analyzed: the single carbon fiber unit cell, a 3×3 array of fibers, and a 5×5 array. Voltage boundary conditions were applied to examine the current distribution throughout the material system, including the response under structural deformation. Improvements and expansions to these efforts are being investigated to examine the effects of large deformation on electrical performance, current distribution, and potential short-outs.