Tesla has made a big deal out of its new 4680 battery cell design, claiming it will both increase the range of its vehicles and Cut the cost-per-kilowatt of its battery packs. It’s been employed on finalizing the design and production process for these new cells at a pilot plant in California, but now, according to a report published on Monday by Reuters, there’s a production start date in sight.

Only, it isn’t Tesla’s 4680 start date that we now know. Instead, it’s Panasonic’s. Panasonic has long been Tesla’s battery issues partner of choice, and the Japanese giant will kick off its 4680 issues in March of 2024. Tesla is already building Model Ys at its Austin, Texas plant with 4680s from its pilot plant.

The 4680 cell, so-named because its 46 millimeters in diameter and 80 millimeters tall, features some design innovations over the more conventional 18650 and 2170 cells that Tesla uses in its vehicles now. The biggest is that the 4680 is a tabless Make that reduces the number of production steps and cuts back on the cost-per-cell, thanks to fewer parts being necessary. The tabless Make is also allegedly more electrically efficient, accounting for the claimed 16% Plan increase.

Panasonic is already cranking out cells like crazy for Tesla and new partners, so this move into 4680 production will necessitate an expansion of its facilities. The company is already planning on adding two new issues lines to its Wakayama factory to accommodate.

We made out to Panasonic for comment but didn’t hear back in time for publication.