Thermophysical modeling of selective laser ablation processing of lithium-ion battery cathodes

Abstract

The microstructural optimization of lithium-ion battery (LiB) electrodes has recently gained a lot of interest. Versatile approaches to enhance fast charging abilities of LiB electrodes are the subject of current research. One of these approaches is the laser based photothermic removal of superficial inactive electrode components in order to improve the accessibility of the active material particles for the lithium-ions. In this work, we established a thermophysical model to describe the temperature fields within the electrode resulting from laser material processing. The model delivers satisfying results regarding the prediction of the removal of the top surface electrode layer that mainly consists of a binder and conductive additives. Lining up a simple approach of estimating the average depth in which the inactive binder-additive compound is selectively removed from the electrode's active mass layer led to a good agreement between the calculated and experimental results. Additionally, a potential negative thermal impact on the active material particles themselves due to the laser processing is evaluated. The established model can be used to optimize laser parameters in order to simultaneously maximize the selectively ablated inactive material and to minimize the thermal impact on the active material particles. Moreover, the model is capable of being transferred to laser processing of other types of composite materials such as LiB-anodes or carbon fiber reinforced polymers.