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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.
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Tesla is nearing its long-awaited unveiling of the all-electric Tesla Roadster, a new report from The Information claims, as the company has said several times this year that the event would take place “soon.”
Now, it appears there is movement on Tesla’s end regarding when it will happen.
The report says that Tesla will unveil the Roadster as soon as this month with a SpaceX version that will utilize cold-gas thrusters to help the vehicle float for a short period of time. This is something CEO Elon Musk has talked about with the Roadster for years.
🚨 The Information is reporting this morning that Tesla is ready to unveil the “flying” Roadster as soon as this month
It’s almost here, folks. pic.twitter.com/IdL4atsucQ
— TESLARATI (@Teslarati) August 14, 2026
Additionally, due to the delays, Tesla explored “a variety of designs” for the Roadster, potentially planning to abandon the design it showed off for the first time in 2017 and adopting an entirely new aesthetic.
According to The Information, Tesla considered utilizing a repurposed Model S Plaid and even wanted to upgrade the look to something like a Lamborghini Countach.
We’ve heard all of these things before, including teases about the date and how “soon” the Roadster will finally be ready to be shown off to the world (for the second time). Musk said that the event would occur in April, then May, then Chief Designer Franz von Holzhausen continued to say it would be coming “soon.”
We do expect to see the Roadster by the end of the year, and now with this new report swirling, it appears it could be sooner rather than later.
The wait has been incredibly long, but there is likely a good reason for it. Tesla’s desire to make the Roadster the craziest vehicle on the road was non-negotiable, and it likely took a lot of time and resources to develop and perfect into something that was safe and suitable for a vehicle like this.
Featured
Tesla finally got its Nevada Robotaxi Permit but with a few catches hard to miss
Nevada granted Tesla’s robotaxi permit, but capped the fleet at just ten vehicles for now.
Tesla has received its robotaxi permit in Nevada, more than two months after regulators closed the public comment period on the company’s application. News of the approval surfaced Wednesday night when Tesla investor and longtime company watcher Sawyer Merritt posted a copy of the interim order, and the Nevada Transportation Authority’s own carrier registry now lists the permit, AVNC Permit 002 under Docket 26-05015, as active for Tesla Robotaxi, LLC.
Tesla asked Nevada in June for authority to run up to 5,000 vehicles in Clark County within a year, however the permit the NTA issued is initially capping Tesla at ten fully autonomous vehicles and confines them to a defined geofence along the Las Vegas Strip corridor. Any expansion of that operating area, or any increase to the fleet size, requires the NTA’s approval first.
Tesla has received its Autonomous Vehicle Network Company permit in Nevada.
The Nevada Transportation Authority says that operations are limited to a maximum fleet of 10 fully autonomous vehicles and shall be conducted only within the Authority-approved Operational Design… https://t.co/Cxfd6GIfDk pic.twitter.com/iOO6wSZkHF
— Sawyer Merritt (@SawyerMerritt) August 13, 2026
The order also sets rules that look more restrictive than what Tesla runs in Austin. Rides are barred on roads with posted speed limits above 45 miles per hour, pickups are off limits within a quarter mile of Harry Reid International Airport without separate authorization, and every vehicle has to carry visible “Robotaxi” markings while notifying riders before each trip that no one is driving. The order also requires “appropriate human supervision”, language that suggests Nevada isn’t ready to let Tesla offer the rides without a safety monitor that it has run in parts of Austin since January. As with standard protocol with robotaxi services, Tesla must report any accident, system failure, or vehicle that becomes stranded on a Nevada road within five business days.
Tesla is entering a market Nevada already knows well. Zoox, the Amazon owned robotaxi company, has run its own autonomous vehicle permit in the state since last year, building up to roughly 100 vehicles and 350,000 rides along the Strip. That history likely explains why the NTA started Tesla at ten cars rather than the fleet size the company asked for. The agency has a template for scaling a permit up once a company proves out its safety record.
Tesla’s Nevada application first surfaced in June, when the company filed for the permit alongside plans for a maintenance hub in southwest Las Vegas. The company has said it won’t meaningfully scale its robotaxi fleet anywhere until FSD v15 ships, expected in late 2026 or early 2027, which makes the ten vehicle cap less of a constraint today than it might look on paper. For now, Tesla has the legal right to start Nevada rides. Whether it starts before FSD v15 arrives is a separate question the permit doesn’t answer.
Tesla Energy has introduced the Powerwall Lease in conjunction with Tesla Electric, making the service available in Texas. This new option delivers whole-home backup power using two Powerwall units for a net monthly cost of $35 after credits, accompanied by a low fixed electricity rate.
Under the lease terms, customers pay a one-time order fee of $100. The base lease payment for the two Powerwalls is approximately $122 per month during the first year, subject to a 3 percent annual escalator thereafter. Enrollment in a qualifying Tesla Electric Backup plan or Virtual Power Plant plan provides an $87 monthly credit.
Powerwall Lease is now available with Tesla Electric in Texas
Whole-home backup for $35/month, with a low fixed electricity rate
– Two Powerwalls, $0 installation
– Storm Watch outage protection
– One app to manage it all pic.twitter.com/oTzqc6K3aF— Tesla Energy (@teslaenergy) August 13, 2026
This credit lowers the effective cost to roughly $35 per month plus applicable tax.
Installation of the standard system carries no additional charge. The package features Storm Watch for outage protection and allows complete management through a single Tesla application. The system supplies continuous whole-home backup capability.
The Powerwall system enables households to maintain electricity during severe storms that disrupt the utility grid. When outages occur, the batteries automatically provide seamless backup power to the home.
Tesla announces 100k Powerwalls are participating in Virtual Power Plants
Tesla Storm Watch monitors weather forecasts and ensures the units are fully charged ahead of anticipated severe weather events so that power remains available throughout the disruption, keeping lights, refrigeration, and other essential systems operating without interruption.
Availability is restricted to select Texas locations where retail electric choice exists. Participants must lease exactly two Powerwall units and maintain continuous enrollment with Tesla Electric. Solar panels cannot be included under this particular lease arrangement.
The monthly credit activates automatically once the system is installed, receives permission to operate, and enrollment is confirmed. To retain the credit, customers are required to stay enrolled in Tesla Electric and fulfill all program conditions.
Nonstandard installations that involve electrical upgrades or special permitting may lead to extra expenses and might impact eligibility for the credit, so be sure to check with either your installer or Tesla to ensure you will still qualify.
Tesla Roadster unveiling nears, and it will fly: The Information
Tesla finally got its Nevada Robotaxi Permit but with a few catches hard to miss
