Tesla’s battery day has been hyped so much that the event will have to include something truly amazing to live up to its expectations. Prior to the highly anticipated event, there has been a leaked picture with what is allegedly a cell from Tesla’s “Roadrunner” line. And if the leak proves to be legitimate, it seems that the battery day will not only meet expectations – it will be even more insane than expected.
The leaked image that was originally published in a report on Electrek, contained a massive battery cell that was allegedly a product of the Roadrunner line. The publication noted that the image was sent through an anonymous source and confirmed by another independent source. From the get-go, it is clear that the cell is massive, closer to a supercapacitor than a traditional battery cell. Preliminary observations from battery enthusiasts online also point to some radical improvements that such a cell design would bring about.
While Electreksources have mentioned that the Roadrunner cell will have approximately double the diameter of the 2170 cells that the electric car manufacturer currently uses in Model 3 and Model Y, Tesla enthusiast @_BRCooper, who is familiar with battery technology, has observed that of the leaked images had the number “054” printed on the page. If this number represents the diameter of the cell, it would indicate that Tesla’s Roadrunner cells adopt a 54 × 98 form factor, which has 10 times the volume of a 2170 cell.
As noted by Jordan Giesige from The limiting factor channel on YouTube, the adoption of a 54 × 98 form factor for its next-generation cells has many implications for the entire battery production process and the performance of Tesla’s vehicles as a whole. With the larger cells, Tesla was able to produce battery packs that are on the order of fewer cells than before. This will result in the company using only 1/10 the number of rolls, cans, electrolyte fillings and welds relative to its current operation. Such a strategy opens the doors to massive cost reductions that can help lower the prices of electric cars to a remarkable degree.
But regardless of its actual size, the Roadrunner cell design appears to be optimized and designed for a cell-to-package drop-in setup. Interestingly, the leaked image of the Roadrunner cell seems to have an electrode design without tables, which Elon Musk has called “far more important than it sounds” last year. Given that the Roadrunner cells are actually inspired by Tesla’s tableless electrode patent, the new form factor could pave the way for more performance and further reductions in production costs.
What’s even more remarkable is that these improvements become possible with just the Roadrunner cell’s new form factor and design. Giesige, for his part, has noted that with the design of the Roadrunner cell and the potential 54 × 98 form factor alone, Tesla may be able to shut down 300 wh / kg before making significant changes to the battery chemistry. Elon Musk actually mentioned an improvement of 30-40% from 250 wh / kg back in 2018, which corresponds to an improvement to 325-350 wh / kg. Musk’s prediction was considered fantastic by critics at the time, but as battery day approaches and leaks begin to emerge around the event, it begins to look more and more likely that 325-350 wh / kg is possible.
See a feature on Roadrunner battery leak in the video below.