Along with developing 4680 battery cells for Tesla; Samsung SDI is also testing shorter versions of the “fat cells” which it expects to supply to other automakers such as Volvo, BMW, and Stellantis.
Manufacturers might build a twin level battery pack by stacking two levels of 4640 cells on top of each other. While the configuration may be heavier and more expensive, it provides the advantage of greater control of battery cell temperatures within the battery pack.
However, as per Samsung SDI, the fundamental cause for the shorter cells is improved manufacturing quality control. The longer the cell, the more difficult it is to precisely align all of the internal components — the cathode, anode, and separator foil. Furthermore, protruding tabs in cylindrical cells must be folded in, which necessitates the use of specialist production equipment.
The added length can also make injecting the electrolyte that lies between those components challenging. Because a longer battery allows electrolytes to flow out when injected, the region between the container and the cap must be cleaned.
Samsung SDI intends to deploy etching laser technology to do this. At this moment, there is no official word on which manufacturers are interested in using the shorter 46-millimeter diameter cells.
Reference- Samsung SDI PR, Electrive, Bloomberg, The Elec