Articles techniques et présentations

Structural Supercapacitors (SSC) are an important group of Multifunctional Energy Storage Composites (MESC) and can potentially play a significant role in lightweight design of aerospace and automotive applications [1]. Therefore, it is important to build accurate models based on the multiphysics involved in these electrical energy storage devices (compare e.g. [2]). As integrated structural parts, an SSC will need to retain its electrochemical performance (e.g. specific capacitance) under mechanical loads. Considering the mechanical-electrochemical coupling in SSC, there is a lack of studies analyzing the effect of mechanical stress on the electrochemical behavior of SSC, as experimentally investigated by Li et al. [3]. Thus, the aim of the current study is to model and simulate the mechanical-electrochemical behavior of the SSC under various load case scenarios with the use of multi-physics simulation software COMSOL Multiphysics®. For this purpose, firstly, the deformations of a MESC structure under various loads was carried out using a finite element analysis (FEM) in the Structural Mechanics Module. The investigated MESC structure consists of carbon fibers as reinforcement and contains polymer as matrix material and as separator. The structure’s resulting static deformations were transformed to an electrochemical model (Electrochemistry Module) to estimate the cyclic voltammetry behavior of the SSC under the applied loads. This approach represents a one-way mechanical-electrochemical coupling. In this way, the mechanical-electrochemical behavior of SSCs can be predicted for various load case scenarios. The obtained knowledge will help to design and predict new composite structures with integrated electrical energy storage functionality. It is expected that up to a critical stress level, the capacitance of SSC will increase by increasing the mechanical stress. At stresses higher than the critical value, the capacitance will depreciate.