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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.
Tesla owners have long griped about the wireless phone charger in the Model Y and other vehicles. It often turns smartphones into miniature ovens rather than reliably topping them up.
Software engineer and Model Y owner Michał Gapiński tackled this issue head-on with a clever DIY upgrade, swapping the cooled wireless charger pad from the China-made Model YL in for the one that came standard in his vehicle.
There are several key differences between the U.S.-built Model Y’s wireless charging pad and the one that Tesla has been installing in the Model YL. The one installed in U.S.-built vehicles lacks active cooling and relies on basic heat dissipation, leading to rapid temperature buildup during charging. In contrast, the Model YL integrates a small fan for active cooling.
Will it fit? Fingers crossed, I want a first YL charger deployed in the regular juniper pic.twitter.com/wWDqSNFVkW
— Michał Gapiński (@mikegapinski) June 2, 2026
This design maintains lower temperatures even in warm ambient conditions, though it does not support faster Qi2 charging on iPhones. The connector matches exactly, making physical swaps feasible on compatible consoles, but coding is required to enable full functionality.
Owners in the U.S. have complained about the wireless charging pad, with many reporting that overheating is fairly common. Within 20 or 30 minutes of placing a phone on the wireless charging pad, many have reported overheating messages on their phones, which halt charging and essentially turn the pad into a fancy place to rest your phone.
Many owners have opted to simply plug their phones into a charging cord. Tesla has acknowledged the problem by releasing several solutions for owners, including a relatively new feature that allows you to simply turn off the charging and simply act as a holder for your phone while driving.
Gapiński said that he sourced the cooled pad affordably from China, and it cost under $200 for the part.
He removed the existing console charger, swapped in the new unit, confirming a perfect connector fit, and handled the trim differences. Since the parameter isn’t fully secured, he enabled it through custom coding outside official Toolbox.
Connector is identical, she fits, now time to code it. https://t.co/Y9idgDrpCq pic.twitter.com/uwwgq6blg7
— Michał Gapiński (@mikegapinski) June 2, 2026
The fan activates quietly, blending with AC and seat cooling. He reported the installation was effective and the wireless charging pad worked perfectly; it even kept the phone cool as it stayed at just 86 degrees Fahrenheit. Many times, the wireless charging pad will bring the phone’s temperature well above 100 degrees, sometimes even being relatively hot to the touch.
The retrofit worked, no issues. First Model Y with a cooled wireless charger! No QI2/faster charging on the iPhone but it does not boil the phone even when it is 30 degrees outside.
The fan kicks in, it is not audible especially with the air conditioning and seat cooling. The… https://t.co/JOyR8Tb1Yo pic.twitter.com/kJcYhQIlYq
— Michał Gapiński (@mikegapinski) June 2, 2026
This retrofit highlighted an elegant, owner-driven solution to a factory shortcoming. It is expected that Tesla will begin installing the cooled charging pads into new cars in the U.S. soon, and hopefully, it will offer some sort of retrofit service or kit to owners here who want to use the charging pad effectively.
For those who love to tinker, it’s an accessible upgrade, proving that innovation thrives beyond the production line.
The Tesla Roadster unveiling could be coming “in a few weeks,” according to the company’s Chief Designer Franz von Holzhausen, who said at the Tesla Takeover Europe Event in Austria that the all-electric hypercar could finally make its way to the production line after years of anticipation.
Von Holzhausen delivered the news just days after The Information reported that Tesla planned to push the Roadster unveiling to August. It was slated for both April and May of this year, but now it seems the company is leaning toward a late Summer event to cap off the heat with perhaps its most anticipated vehicle of all-time.
🚨 Tesla Chief Designer Franz Von Holzhausen, speaking to the crowd at Tesla Takeover Europe, said at the event that the Roadster is coming “in a few weeks,”
Multiple attendees have confirmed this pic.twitter.com/B1v6yb2Geq
— TESLARATI (@Teslarati) June 6, 2026
Franz has been with Tesla since 2008, and has played a pivotal role in the iconic design language the company has utilized with its vehicles. Speaking to the crowd in Austria virtually, von Holzhausen’s comments injected fresh excitement into a project that has been plagued by delays for nine years.
The second-generation Roadster promises to redefine supercar standards. Tesla’s website still highlights ambitious targets: 0-60 mph in under 1.9 seconds (with optional SpaceX thruster pack potentially achieving 1.1 seconds or less), a top speed exceeding 250 mph, and a range of about 620 miles.
Equipped with a tri-motor all-wheel-drive setup delivering over 1,000 horsepower, the four-seater aims to blend blistering acceleration, everyday usability, and innovative features like cold gas thrusters for short-hop capabilities, technology that will combine the project with SpaceX.
But years after the company promised to start production, which was slated for 2020, the timeline for the Roadster has continued to shift.
Tesla has strung along those who have put $50,000 deposits down, as well as fans and enthusiasts of the company who have been long awaiting the company to bring forth a car truly designed for the human driver, and not autonomy. The Roadster is more than just a halo vehicle for Tesla; it showcases the company’s ability to push the boundaries while incorporating synergies from other Musk companies.
However, it has to make it to production, which is something Musk and Co. have pushed back repeatedly.
As Tesla navigates Robotaxi development and broader autonomy goals, the Roadster serves as a reminder of its performance roots. If von Holzhausen’s timeline holds, fans could witness this engineering marvel by late June or early July 2026. Whether a full unveiling, demo, or initial deliveries, it marks a milestone for electric supercars.
Tesla has reportedly pushed the unveiling of the Roadster once again, but there are also evidently new details about the event that the company plans to show off.
The Information reported this morning that Tesla will now unveil, for the second time, the next-generation Roadster in August, a further delay from the multiple timeline that the company had previously stated.
The report has not been confirmed or denied by Tesla at any capacity.
It also states the unveiling event will take place in Texas, the same place that Tesla executives revealed in May would be the place of manufacture for the company’s highly-anticipated supercar, which boasts a top speed of over 250 MPH and 650 miles of range, according to its website.
Tesla is also expected to showcase the SpaceX package, which will be used for faster acceleration and potentially hovering capabilities, at the unveiling event, the report states. Musk has always planned for this to happen, but now it seems it is more realistic than ever
The report also states the Roadster unveiling is planned for August pic.twitter.com/By26XZIJzU
— TESLARATI (@Teslarati) June 5, 2026
The Roadster has had its unveiling date and manufacturing date pushed back on many occasions. It was set to start production in 2020, but the COVID-19 pandemic crippled supply chain operations, forcing Tesla to push its timeline back considerably.
However, COVID has been over for some time, and Tesla has still not managed to successfully schedule and execute an unveiling event, which is something fans and enthusiasts, as well as those who have put down a $50,000 deposit, have been waiting for.
The vehicle was close to completion last year, but Musk truly wanted Lars Moravy and Franz von Holzhausen to push the limits of the Roadster. In July of last year, Moravy said:
“Roadster is definitely in development. We did talk about it last Sunday night. We are gearing up for a super cool demo. It’s going to be mind-blowing; We showed Elon some cool demos last week of the tech we’ve been working on, and he got a little excited.”
It is important to note two things: Tesla has not confirmed these details, and the company has regularly pushed these dates back. Until Tesla sends out formal invitations with a concrete date, taking any unveiling event reports with a grain of salt is a good idea.
Tesla owner fixes common feature complaint with crafty DIY retrofit
Tesla Roadster unveiling teased to be happening ‘in a few weeks’ by exec
