Investigation on the blanking properties of thin multi-layer electrode of lithium-ion battery

Blanking process is a commonly-used method to manufacture the electrodes of lithium-ion batteries. In this paper, the blanking properties of electrodes are investigated with a simulative approach, and a general framework for multi-layer electrode is put forward. Uniaxial stretching and compression tests are conducted on cathodes and anodes to acquire their mechanical properties. Several modelling scenarios are compared in finite element software ABAQUS, to select the proper mechanical model for electrodes. A multi-layer composite model with tie constraint connecting different layers is finally chosen, in which crushable foam material is applied for active material layers, and solid metal material is used for current collectors. From the results of blanking simulations, it is found that upper and lower active material layers work as buffers against blanking force. Therefore, cutting edge regions of middle current collectors bend significantly, and long burrs appear there. SEM images are in line with simulation results. The relationships between clearance, corner radius of dies and current collector burr length are also investigated. Burr length will increase simultaneously with the increase of clearance or corner radius. But burr length is more vulnerable to the change of clearance than that of radius.