On Battery Day, Elon Musk promised to deliver a new, bigger cylindrical battery called the 4680. Elon promised that his new cell would deliver 5 times the energy of the existing 2170 cells. We know that Musk makes a lot of big promises that are often a bit late arriving but this promise is big in a number of ways.
Until now, nobody could make big cells like the 4680 because they would get too hot. Little cells dissipate heat easier than big cells. By inventing the tabless battery, Tesla’s 4680 design has less electrical resistance so generates less heat and is thus allowed to be bigger. The thing about the bigger cells is that they store 5 times the energy but are less than 5 times as expensive to manufacture. Furthermore they are not 5 times as heavy so your new Tesla will have a longer range.
Less expensive is great for Tesla but it also means that the ESPcat (Electric Solar Powered Catamaran) will have a less expensive battery. No Tesla is not sending me a set of 4680 cells but it means that these new , low cost cells will force the price of lithium batteries down even further and faster. Battery prices are already dropping at an alarming rate.
The smaller, 2170 cells store 17.3 Wh of energy.(1) The new, big 4680 cell stores 5 x 17.3 which is 86.5 Wh. Now we hear that Panasonic has a test line and is making samples that actually deliver on the 5 times promise.(2)
Meanwhile, Chinese company BAK has produced a 4680 prototype which claims to produce 25 Ah which should equate to even more than the promised 86.5 Wh promised by Elon. (3) 25 Ah times 3.7 V = 92.5 Wh. Chinese companies are a bit like Tesla and are prone to exaggeration but two suppliers is a good thing.
One way or the other, it looks like Elon’s big battery promise has come to fruition.