The next generation of fast charging methods for Lithium-ion batteries: The natural current-absorption methods

The fast charging of Lithium-Ion Batteries (LIBs) is an active ongoing area of research over three decades in industry and academics. The objective is to design optimal charging strategies that minimize charging time while maintaining battery performance, safety, and charger practicality. The main problem is that the LIB technology depends on multi-disciplinary engineering factors that form rapidly varying intrinsic states in the cell during the charging process. These factors take the form of interdependent electrochemical, structural, and thermo-kinetic perspectives. Here, the list can grow as electrochemical changes; charge transfer, ionic conductivity, structural transformations; mass/particle transfer, migration, diffusion, and thermo-kinetic exchanges; phase transitions, heat effects, and collectively their inter-dependencies. Fast charging intensifies this varying nature making it very difficult to achieve an optimal process. In fact, many charging strategies fail to adhere to such rapid variations and are based on predefined/fixed parameters such as voltage, current, and temperature, individually or collectively, that enforce and aggregate stress on the LIBs. Consequently, fast charging accelerates battery degradation and reduces battery life. In order to facilitate the design of optimal fast charging strategies, this paper analyzes the literature around the influences of intrinsic factors on the LIB charging process under electrochemical, structural, and thermo-kinetic perspectives. Then, it examines the existing charging strategies with a new categorical analogy of; 1) memory-based, 2) memory-less, and 3) short-cache, showing their efforts to achieve the optimal charging targets and challenges in adapting to the demanded intrinsic variations. Accordingly, a potential paradigm shift for the next generation of LIBs’ fast charging strategies has been identified in the new area of short-cache-based natural current-absorption-driven charging strategies. Importantly, this new approach is competent in bringing the practical intelligence necessary to adapt the control of LIB fast charging over rapid intrinsic variations.