An electrochemical-mechanical coupled multi-scale modeling method and full-field stress distribution of lithium-ion battery

The rapid development of lithium-ion batteries has made the market more and more concerned about their lives. A large number of studies have shown that the alternating diffusion-induced stress caused by the cyclic charging and discharging processes can significantly shorten the service life of a battery. In recent years, scientists have tried to reveal the distributions and evolutions of the internal stress in lithium-ion batteries during operation by means of experiments and simulations, so as to propose guidance for their design and application. However, the existing numerical simulation framework is still limited to the particles, electrodes and battery units, rather than a battery cell. It is urgent to develop a method that can obtain the full-field stress distributions in commercial lithium-ion battery cells during working, so as to reveal the influence of stress on their lives, and further improve the efficiency of design and optimization. In this paper, an electrochemical-mechanical coupled multi-scale modeling method for lithium-ion batteries is proposed, which solves the technical problem of cross-scaled modeling and simulation from battery units to battery cells. Taking a pouch lithium-ion cell as an example, the lithium concentration distribution, potential distribution, and current density distribution of the battery unit, as well as the full-field displacement distribution, strain distribution and stress distribution of the battery cell during charging are obtained and analyzed. And the assumption, adaptability and potential applications of the method are discussed. It provides a new technical means and insight into the properties of lithium-ion batteries, and even solid-state batteries in the future.