Computational Simulation of Composite Structural Batteries

Structural battery composites are multifunctional materials that store electrical energy while also bearing structural loads. These materials are particularly applicable to electric automobiles, aircraft, spacecraft and other energy demanding and weight sensitive applications. The auxiliary electric charge from the material will provide power for onboard electronics and extend the range without decreasing the range or the payload capacity. Current structural battery designs include solid-state battery technology with woven carbon or glass fiber composites as a structural reinforcement. The computational finite element method (FEM) was used to simulate various material reinforcements to assess the optimal material selections and designs. Full scale panel laminates were analyzed using a 3 point bend test configuration to determine the flexural stiffness and strength of each structural battery laminate configuration. Fabrication artifacts due to the vacuum bagging composite fabrication technique were assessed to determine the necessary gasket material needed to maintain structural integrity. In addition, plain weave glass fiber/epoxy and unidirectional carbon fiber/epoxy tape were compared to determine the optimal material for interstitial layers between the multiple battery cells in a single panel. For the case of a gasket around the battery layers in the panel, a parametric study was developed to determine the effects of different possible gasket materials. In addition, a micromechanics approach was utilized to analyze the conductivity of carbon fiber/epoxy composites for possible use in the solid-state battery for improved energy density and structural performance. Incorporation of high conductivity epoxy as a matrix in a carbon fiber/epoxy composite significantly increases the overall electrical performance of the composite to the point that integration into the solid-state battery unit cell is possible.