Electrode alignment refers to the proper positioning and registration of the anode and cathode (and separator) within a battery cell. The separator always overhangs the anode electrode in all directions and the anode electrode overhangs the cathode electrode. This is required to avoid the possibility of a direct short circuit, in the case of no separator overhang, or plating of metallic lithium in the case of no anode overhang. Both of these cases could cause unsafe conditions to occur during cycling, which could result cells catching fire. Precise electrode alignment is thus critical for both performance and safety of the cell.
Manufacturers use various techniques to maintain alignment, such as guide pins in stacking machines or alignment PID controllers and careful tension control in winding machines. NOVONIX, when prototyping cells or evaluating manufacturing processes, pays attention to electrode alignment to ensure reliable results. For instance, when NOVONIX assembles a stacked pouch cell, they ensure the stack of layers is properly registered By maintaining strict electrode alignment in their test cells, NOVONIX also mirrors the quality control needed for mass production.
