Here’s what Tesla will put in its new batteries
Tesla’s “battery day” Tuesday revealed a surprising amount of information about projects the company has kept under wraps. The presentation described changes and improvements to just about every aspect of its battery packs, with big-picture implications for the claim that a $25,000 Tesla vehicle would be possible in about three years. (See the previous coverage from Ars’ Timothy Lee for more on that.) But it wouldn’t be a Tesla announcement without vague timelines, and it was a little unclear which improvements are ready to go now—and which ones they’re just expecting to succeed in the next couple of years.
Without specific numbers or concrete details, assessing the announcements takes a little guesswork. But we can compare all this to other industry trends and to published research to get some idea.
Battery in a can
Let’s start with two things Tesla claimed already exist at its pilot production plant: its new cell design and some improvements in manufacturing. Tesla got off the ground using existing and commonly available cylindrical 18650 lithium-ion cells, while most EVs have been built with flat pouch or prismatic cells (more like the thin batteries in phones and laptops). In a cylindrical cell, long sheet-like anodes, separators, and cathodes are sandwiched, rolled up, and packed into a cylinder-shaped can. The cathode and anode sheets each have one skinny “tab” that connects to the positive and negative terminals of the battery can.