The response from the wall street media to Battery Day was muted, to the point of boredom, and the stock price actually dropped. Perhaps everyone thought Elon Musk was going to unveil a working quantum vacuum battery. Instead he unveiled something more pedestrian, another cylindrical battery with a nickel graphite chemistry – the 4680 battery.
The other aspect wall street media found depressing was that Tesla was not rolling them off the production line the next day. Rather they were in the final stages of development. For those seeking instant gratification it was not as thrilling as when the first iPhone was unveiled by Steve Jobs. However the consequences for Tesla, and the world Tesla is disrupting, may, in the long run, prove to be way more profound.
The novel use of the optimal dimensions (46 mm in diameter and 80 mm tall), so sensible but thought of by no-one until now, the tabless design, reducing the distance that electrons travel to the height of the electrode (rather than its wound length) massively reducing the energy lost to heat, all combine to make the cell six times more powerful than its predecessor and increase range by 16 percent.
According to a video of the batteries teardown the battery walls, integral to the structural integrity of the car (thanks to the structural battery pack in which the battery pack itself acts as the car’s chassis) are very thick.
The ultimate plan is to use the battery for all of Tesla’s vehicles. This is not just because of improved power to weight, there are also significant manufacturing costs saved. The diecasted front and rear end depend upon the startural battery pack, which in turn depends upon the 4680. The Model Y’s old 2170 battery pack contains 4400 individual cells, which required four spot welds for each cell. The 4680 pack contains 830 cells which require only two welds. This will reduce costs 56% per kWh.