Large lithium-ion battery packs are composed of multiple individual cells, each of which contains a pair of compacted lithium-ion powder pellets separated by a collector plate. Composed of proprietary mixtures of lithium and other elements, the pellets must be as identical as possible in terms of size, shape, density and composition. Any variation will adversely affect the chemical and electrical properties of the cell and ultimately shorten the life of the battery.
After they are formed, the pellets must be joined to the collector in a manner that maintains not only their “in process” characteristics, but also creates a perfectly balanced cell with the collector exactly centered between the pellets. Any variation in the cell’s balanced geometry can reduce battery life and overall quality.