A sequential multi-scale study on mechanical damage and capacity decay in pouch lithium-ion batteries

Mechanical failure of mesoscopic electrode particles caused by electrochemically induced stress is a critical factor contributing to the macroscopic performance degradation of lithium-ion batteries. Most existing multi-scale studies on lithium batteries rely on Bruggeman coefficients for equivalent performance analysis without accounting for mesoscopic electrode structures. Few models integrate macroscopic-mesoscopic stress transfer relationships or damage-inclusive constitutive laws to analyze the impact of mechanical damage on electrodes. Addressing these gaps, this study investigates mesoscopic electrode damage behaviors during charge-discharge cycles induced by lithiation or delithiation. Continuous medium damage effects on electrode performance is analyzed. A sequential multi-scale model incorporating mesoscopic electrode damage is established, and the stress amplification factor method is employed to quantify macroscopic battery capacity decay caused by mesoscopic damage. The capacity decay mechanism of lithium-ion batteries is discussed from a mesoscopic damage perspective.