Application of digital image correlation technology in investigating mechanical-related issues of lithium batteries

High energy and power densities are key development goals for lithium-ion batteries. However, mechanoelectrochemical coupling attenuation issues have restricted the breakthroughs in battery technology. Digital image correlation (DIC) technology has played a key role in revealing the multi-field-coupling problems. Herein, the setups, operating principles and application points of DIC-based testing systems were summarized. The application of optical DIC technology in the study of mechanical behavior and multi-field coupling effects in both traditional liquid electrolyte-based lithium-ion batteries and solid-state lithium metal batteries was systematically reviewed. Furthermore, the innovative integrated application and development of DIC technology with non-optical imaging equipment and other in situ/operando techniques were outlined and discussed. Finally, the challenges and feasible development tendencies associated with DIC were analyzed and proposed. This review aims to clarify the application potential and development strategies of DIC technology in studying the mechanical behavior of batteries and coupling theory among multiple physicochemical fields within batteries. This is critical for exploring the performance degradation mechanisms and architectural design strategies of high-performance batteries.