News
Tesla ‘Roadrunner’ cell leak hints that Battery Day will be more insane than expected
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. In the lead up to the highly-anticipated event, a leaked image featuring what is supposedly a cell from Tesla’s “Roadrunner” line has emerged. And if the leak proves legitimate, it would appear that Battery Day will not only meet expectations — it will be even more insane than expected.
The leaked image, which was initially published in a report on Electrek, featured a massive battery cell that was supposedly 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 evident that the cell is massive, closer in size to a supercapacitor than a traditional battery cell. Initial observations by battery enthusiasts online also point to some radical improvements that such a cell design would bring.
While Electrek’s sources have mentioned that the Roadrunner cell will feature roughly double the diameter of the 2170 cells that the electric car maker currently uses in the Model 3 and Model Y, Tesla enthusiast @_BRCooper, who is familiar with battery tech, has observed that one of the leaked images had the number “054” printed on its side. If this number represents the cell’s diameter, it would point to Tesla’s Roadrunner cells adopting a 54×98 form factor, which has 10x the volume of a 2170 cell.
As noted by Jordan Giesige of The Limiting Factor channel on YouTube, adopting a 54×98 form factor for its next-generation cells has numerous implications for the entire battery manufacturing process and the performance of Tesla’s vehicles as a whole. With the larger cells, Tesla could produce battery packs that have an order of magnitude fewer cells than before. This would result in the company only using 1/10 the number of rolls, cans, electrolyte fills, and welds compared to its current operations. Such a strategy opens the doors to massive cost reductions that could help bring down the prices of electric cars to a notable degree.
But regardless of its actual size, the design of the Roadrunner cell appears to be optimized and designed for a cell-to-pack drop-in setup. Interestingly enough, the leaked image of the Roadrunner cell seems to have a tabless electrode design, which Elon Musk has dubbed is “way more important than it sounds” last year. Provided that the Roadrunner cells are indeed inspired by Tesla’s tabless electrode patent, the new form factor could pave the way to more performance and further reductions in production costs.
What’s even more notable 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 Roadrunner cell’s design and potential 54×98 form factor alone, Tesla may be able to close in on 300 wh/kg before making any significant changes to its battery chemistry. Elon Musk actually mentioned a 30-40% improvement from 250 wh/kg back in 2018, which translates to an improvement to 325-350 wh/kg. Musk’s prediction was considered fantastical by critics then, but as Battery Day approaches and leaks start to emerge about the event, it is starting to look more and more likely that 325-350 wh/kg is feasible.
Watch a feature on the Roadrunner battery cell leak in the video below.
News
Tesla FSD’s newest model is coming, and it sounds like ‘the last big piece of the puzzle’
“There’s a model that’s an order of magnitude larger that will be deployed in January or February 2026.”
Tesla Full Self-Driving’s newest model is coming very soon, and from what it sounds like, it could be “the last big piece of the puzzle,” as CEO Elon Musk said in late November.
During the xAI Hackathon on Tuesday, Musk was available for a Q&A session, where he revealed some details about Robotaxi and Tesla’s plans for removing Robotaxi Safety Monitors, and some information on a future FSD model.
While he said Full Self-Driving’s unsupervised capability is “pretty much solved,” and confirmed it will remove Safety Monitors in the next three weeks, questions about the company’s ability to give this FSD version to current owners came to mind.
Musk said a new FSD model is coming in about a month or two that will be an order-of-magnitude larger and will include more reasoning and reinforcement learning.
He said:
“There’s a model that’s an order of magnitude larger that will be deployed in January or February 2026. We’re gonna add a lot of reasoning and RL (reinforcement learning). To get to serious scale, Tesla will probably need to build a giant chip fab. To have a few hundred gigawatts of AI chips per year, I don’t see that capability coming online fast enough, so we will probably have to build a fab.”
NEWS: Elon Musk says FSD Unsupervised is “pretty much solved at this point” and that @Tesla will be launching Robotaxis with no safety monitors in about 3 weeks in Austin, Texas. He also teased a new FSD model is coming in about 1-2 months.
“We’re just going through validation… https://t.co/Msne72cgMB pic.twitter.com/i3wfKX3Z0r
— Sawyer Merritt (@SawyerMerritt) December 10, 2025
It rings back to late November when Musk said that v14.3 “is where the last big piece of the puzzle finally lands.”
With the advancements made through Full Self-Driving v14 and v14.2, there seems to be a greater confidence in solving self-driving completely. Musk has also personally said that driver monitoring has been more relaxed, and looking at your phone won’t prompt as many alerts in the latest v14.2.1.
This is another indication that Tesla is getting closer to allowing people to take their eyes off the road completely.
Along with the Robotaxi program’s success, there is evidence that Tesla could be close to solving FSD. However, it is not perfect. We’ve had our own complaints with FSD, and although we feel it is the best ADAS on the market, it is not, in its current form, able to perform everything needed on roads.
But it is close.
That’s why there is some legitimate belief that Tesla could be releasing a version capable of no supervision in the coming months.
All we can say is, we’ll see.
Investor's Corner
SpaceX IPO is coming, CEO Elon Musk confirms
However, it appears Musk is ready for SpaceX to go public, as Ars Technica Senior Space Editor Eric Berger wrote an op-ed that indicated he thought SpaceX would go public soon. Musk replied, basically confirming it.
Elon Musk confirmed through a post on X that a SpaceX initial public offering (IPO) is on the way after hinting at it several times earlier this year.
It also comes one day after Bloomberg reported that SpaceX was aiming for a valuation of $1.5 trillion, adding that it wanted to raise $30 billion.
Musk has been transparent for most of the year that he wanted to try to figure out a way to get Tesla shareholders to invest in SpaceX, giving them access to the stock.
He has also recognized the issues of having a public stock, like litigation exposure, quarterly reporting pressures, and other inconveniences.
However, it appears Musk is ready for SpaceX to go public, as Ars Technica Senior Space Editor Eric Berger wrote an op-ed that indicated he thought SpaceX would go public soon.
Musk replied, basically confirming it:
As usual, Eric is accurate
— Elon Musk (@elonmusk) December 10, 2025
Berger believes the IPO would help support the need for $30 billion or more in capital needed to fund AI integration projects, such as space-based data centers and lunar satellite factories. Musk confirmed recently that SpaceX “will be doing” data centers in orbit.
AI appears to be a “key part” of SpaceX getting to Musk, Berger also wrote. When writing about whether or not Optimus is a viable project and product for the company, he says that none of that matters. Musk thinks it is, and that’s all that matters.
It seems like Musk has certainly mulled something this big for a very long time, and the idea of taking SpaceX public is not just likely; it is necessary for the company to get to Mars.
The details of when SpaceX will finally hit that public status are not known. Many of the reports that came out over the past few days indicate it would happen in 2026, so sooner rather than later.
But there are a lot of things on Musk’s plate early next year, especially with Cybercab production, the potential launch of Unsupervised Full Self-Driving, and the Roadster unveiling, all planned for Q1.
Tesla has added the 15th automaker to the growing list of companies whose EVs can utilize the Supercharger Network this year, as BMW is the latest company to gain access to the largest charging infrastructure in the world.
BMW became the 15th company in 2025 to gain Tesla Supercharger access, after the company confirmed to its EV owners that they could use any of the more than 25,000 Supercharging stalls in North America.
Welcome @BMW owners.
Download the Tesla app to charge → https://t.co/vnu0NHA7Ab
— Tesla Charging (@TeslaCharging) December 10, 2025
Newer BMW all-electric cars, like the i4, i5, i7, and iX, are able to utilize Tesla’s V3 and V4 Superchargers. These are the exact model years, via the BMW Blog:
- i4: 2022-2026 model years
- i5: 2024-2025 model years
- 2026 i5 (eDrive40 and xDrive40) after software update in Spring 2026
- i7: 2023-2026 model years
- iX: 2022-2025 model years
- 2026 iX (all versions) after software update in Spring 2026
With the expansion of the companies that gained access in 2025 to the Tesla Supercharger Network, a vast majority of non-Tesla EVs are able to use the charging stalls to gain range in their cars.
So far in 2025, Tesla has enabled Supercharger access to:
- Audi
- BMW
- Genesis
- Honda
- Hyundai
- Jaguar Land Rover
- Kia
- Lucid
- Mercedes-Benz
- Nissan
- Polestar
- Subaru
- Toyota
- Volkswagen
- Volvo
Drivers with BMW EVs who wish to charge at Tesla Superchargers must use an NACS-to-CCS1 adapter. In Q2 2026, BMW plans to release its official adapter, but there are third-party options available in the meantime.
They will also have to use the Tesla App to enable Supercharging access to determine rates and availability. It is a relatively seamless process.
Tesla FSD’s newest model is coming, and it sounds like ‘the last big piece of the puzzle’
SpaceX IPO is coming, CEO Elon Musk confirms
