We recently took a look at the new 2170 battery cell being developed by Tesla [NASDAQ: TSLA] and Panasonic. The 2170 battery will be used in the new Tesla Model 3. However, over the past few years Tesla has been using Panasonic’s 18650 battery cell in its Model S and X. The 18650 battery cell is also commonly used in laptops and other everyday electronic devices. But, its use in an electric vehicle requires thousands of these battery cells to be housed in a unique arrangement, complete with control electronics and a sophisticated cooling mechanism, inside the floorpan of the car.
Jalopnik* notes, “The Tesla battery pack is something of a triumph of packaging. The battery pack is integrated into the skateboard-like chassis of the car, making a self-contained drivetrain-and-energy-storage unit that allows for really flexible body packaging… There are multiple layers of aluminum skin, moisture shields, and even some sort of blue fluid they call ‘Tesla Soup’ that must be extracted. This process looks tedious and involved, but it’s all worth it once you get to those sweet, juicy battery packs inside.”So what’s inside a Tesla Model S battery pack? “The chassis and outer cover are held together by a huge array of bolts and Torx screws… Under the cover is a second cover that is glued down, this needs to be carefully pried off to reveal the modules and their cells. The coolant is drained, and the modules disconnected. This last task is particularly hazardous, as the pack delivers hundreds of volts DC at a very low impedance. Then each of the sixteen packs [modules] can be carefully removed. The packs [modules] each contain 444 cells, the pack voltage is 24 V, and the energy stored is 5.3 kWh.”