Still in separate streams, the cathode and anode materials are applied, respectively, to aluminum and copper foil. The positive and negative electrodes are then each pressed to the correct thickness before being cut down to the proper size and dried to remove any moisture.
ASSEMBLY
The positive and negative electrodes are brought together to form the cell. A specially coated separator is inserted between the two sides to keep them apart and prevent any internal short circuits.
Once the separator is in place, LG’s process for pouch cells departs from other methods for manufacturing cells. Cylindrical battery cells, which closely resemble conventional tubular batteries, are rolled and fitted into enclosures, Gray said. Pouch cells are built by stacking sets of cells and slipping them into their softshelled enclosures.
The partially sealed pouches are then flooded with electrolyte.
“That allows the electrons to go between the positive and negative,” Gray said, “and then you seal [the pouch] up.”
FORMATION
The final step in cell production lasts 10-21 days, Gray said, “This is where the batteries come alive.”
The now-active cells are placed in a warehouse-like environment and charged and discharged to check performance and to detect problems. LG’s target is to have 95 per cent of its cells perform properly through the “aging” process, Gray said. Cells that exhibit problems are discarded, while those that clear quality control are ready to be packaged into modules or sold individually, depending on customer needs.
EV INTEGRATION
To be fitted into EVs, individual battery cells from the new Windsor plant will first be packaged into modules. Sets of modules are then combined with energy management and cooling systems to form a completed battery pack.
There is no fixed number of cells in a module or modules in a pack, Gray said. That means the exact configuration of Stellantis’ batteries will be left up to the automaker.
