BMW Group Plant Leipzig’s first cell coating line has gone into series operation as e-component production at the site continues to gain momentum. By 2024 the two existing module assembly lines will be complemented by a third, as well as four more cell coating lines and two more high-voltage battery assembly lines. The four coating lines will enter series operation during the course of this year at roughly two-month intervals.Covering 2,300 square meters, the new cell coating system at the BMW plant in Leipzig is located in the former production hall of the BMW i3, where production was phased out in the summer of last year. Straight afterwards the space was converted for e-component manufacturing in less than six months, and associates underwent the relevant training.The new coating line can handle more than 10 million cells a year, or over 2,300 an hour. The coated cells are then used on the battery module production line in Leipzig, to make modules for the fully electric BMW i4* and BMW iX1. A further line at the facility is producing battery modules for the BMW iX.High-voltage battery production happens in three stages: cell coating, module production and assembly of the battery itself. The processes are highly automated.The BMW Group sources its cells from partners who manufacture them exactly to specification. The type that is used depends on the vehicle concerned and is chosen to ensure the best possible characteristics.Coating lithium-ion cells consists first of pre-treating and patterning their surfaces with a laser. This involves the laser beam “chiseling” a texture into the outside of the uncoated cell to increase its surface area and reduce the surface tension of the aluminium casing. Next, the cells are plasma-cleansed to remove any dirt particles and oxides. Together, these two processes improve the adhesiveness of the surface, ready for the coating to be applied. It is administered by a specially developed machine that coats the cells in two layers, which are then hardened by UV and offer the best possible insulation for the cells. Finally, a fully automated three-stage quality control process is carried out in which the thickness and surface quality of the coating are inspected. A high-voltage test is conducted to ensure the coating is completely free from defects.