Damage and Delamination Modeling of Multifunctional Composite Structural Batteries

摘要

Structural battery composites are capable of storing and delivering electricalenergy and bear structural loads. It is important to analyze the stiffness and strength ofthese composites, particularly in bending loading configurations. Damage of structuralbatteries is of particular importance in structural batteries due to the energy storagecomponent. Two structural battery material systems were considered. The first batterycell uses copper and aluminum foils as electrodes and carbon paper as currentcollectors. The second material system incorporates carbon fiber fabric coated withnickel and iron through electrodeposition as the multifunctional electrodes. These stiffcarbon fiber fabrics provide excellent mechanical properties. For sufficient electricalenergy capacity storage for use as the chassis of a CubeSat, it was calculated thatseven layers per panel would be required. Multi-layer panels consisting of sevenbattery layers as a core with external structural reinforcement were tested. Physicaland virtual three point bend tests were completed on these material systems. PrototypeCu-Al panels were fabricated and tested in a 3 point bend test configuration untilultimate failure. The damage initiation and propagation was analyzed throughqualitative and quantitative analyses. Damage morphology took the form of layerdelamination and material cracking within the battery layers. Computational finiteelement simulations matching the mechanical testing geometry were completed tofurther understand the mechanism involved in the damage of these composites.Simulated Cu-Al panels showed a larger stiffness, however the progression of damagewas well represented in the models. The Ni-Fe carbon fiber battery was superior instiffness and strength. Overall, these composites show promise that these can beutilized as structural materials that store electrical energy.