Until now, battery-pack production has followed the same basic procedure. A company that specializes in making battery cells like Panasonic or LG Chem makes the individual cells and then the automakers take those cells and package them into a battery pack.
In other words, the cell production is a wholly separate process from making the pack that goes in the car. Why not integrate the two separate procedures?
In the old case, single battery cells come out of the battery cell plant. In Tesla’s patent application, small cell groups come out of the cell manufacturing plant. These small cell groups are then combined like "Lego" blocks into complete batteries. It’s not really a cell-manufacturing plant, but instead, it's a battery submodule (usually a parallel cell group) manufacturing plant.
As an example of how the two processes can be combined: the current collector plate is now a circuit board that incorporates multiple functions like fusing, overpressure and cell balancing. This circuit board also doubles as the end caps of the cells.
However, we all know that, just because Tesla releases a patent application, it doesn’t mean said patent will ever be used in Tesla’s car production line. Tesla has released tons of patents and not all of them actually come to fruition.
Still, integrating the pack production process with the cell making process seems so logical it's hard to imagine NOT doing it. The potential for dropping pack costs seems to be there in spades.
Now, we find out that the Chinese battery company CATL has already introduced what appears to be an almost identical process. CATL calls the process “Cell to Pack.”.
The monumental press release came out just this September of 2019. Unfortunately, we have not been able to glean many specific details, but CATL seems to be advertising higher energy density, presumably due to tighter packing of the cells. They also mention eliminating “modules,” which would logically result in tighter cell packaging and higher energy density at the pack level.
So, while there clearly appears to be differences in how Tesla and CATL are integrating the pack and cell production, the overall idea and process is similar: taking two wholly separate manufacturing processes (cell manufacturing and pack manufacturing) and combining them into one process resulting in a much more simplified, more efficient and lower-cost method of making battery packs.