Fatigue and Failure Mechanism Induced by Mechanical Strain and Electrochemical Cycling of Li⁺ Intercalation and Deintercalation in CF Structural Batteries

Structural batteries offer multiple advantages, providing viable solutions for electric mobility. By playing a dual role as both an energy storage device and structural component, they can achieve a larger transportation range and greater safety. However, they are exposed to external mechanical loads that can exacerbate the mechanical stresses induced by the electrochemical cycling. It should be noted that batteries undergo stress due to the intercalation and deintercalation of Li⁺. In fact, when lithium ions are inserted into the active materials, mechanical tension occurs, which can cause cracks and pulverization of the particles. Consequently, the individual particles lose their electrical connectivity. Another aging process is caused by the expansion of the active materials due to mechanical strain during the insertion of lithium ions, resulting in changes in particle volume. In addition to this electrochemical stress, there is added mechanical stress due to their role as a structural component. This paper explores the superposition of these two phenomena and tries to understand the fatigue and failure mechanisms induced by mechanical strain and electrochemical cycling (Li⁺ intercalation/deintercalation) in structural batteries. To achieve this, we plan to use the fiber bundle model as a theoretical approach to study the damage and fracture of fiber-reinforced composite materials.