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Tesla battery researchers open path to all-electric range extender concept

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Tesla has solidified itself as an industry leader when it comes to electric vehicles and their range. However, an EV’s range could always be improved, and the company has taken great efforts to make this possible. One of these was outlined by Tesla’s battery researchers, who recently published the results of a test that cycles lithium metal on graphite to form hybrid lithium-ion/lithium metal cells. This particular innovation could open the door to an all-electric range extender.

Other automakers have used range extenders in the past, but they’ve been comprised of small petrol-powered engines that are used as a generator to recharge the vehicle’s battery pack when it is low on range. The process of cycling lithium metal on graphite, on the other hand, could lead to a 20% higher energy density than the traditional lithium-ion cells that power the Tesla’s vehicles.

Tesla’s battery research team, led by Jeff Dahn of Dalhousie University, has found a way to create a range extender of sorts without having to keep a small gas engine in the vehicle. Tesla detailed its findings in a research paper that was published to ScienceDirect on April 30. Titled “Cycling Lithium Metal on Graphite to Form Hybrid Lithium-Ion/Lithium Metal Cells,” Dahn and his researchers outlined the testing process.

The findings proved a possible 20% increase in range when using the range extender, which is comprised of “hybrid cells” that use Lithium-Ion and Lithium Metal. The cells also used an optimized electrolyte, and pressure enabled reversible plating on graphite.

The paper states:

“A hybrid anode cell design is proposed involving lithium metal plating on top of graphite that provides a 20% increase in energy density over conventional lithium-ion cells. Pouch cells with hybrid graphite-lithium metal anodes cycled with conventional electrolytes fell below 80% capacity in under 15 cycles. However, with a dual-salt electrolyte and applied mechanical pressure optimized for lithium metal cycling, hybrid cells achieved over 150 full (100% utilization) cycles before falling below 80% capacity with a CE of 99.6% for lithium metal plating on graphite.

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“We also found that intermittent high energy (100% utilization) cycles utilizing lithium metal can be dispersed among hundreds of conventional lithium-ion cycles where only the graphite is utilized. Operating the cell with this intermittent protocol shows minimal impact to the underlying graphite capacity. Therefore, these hybrid cells can operate well in “lithium-ion mode” with periodic high energy full cycles accessing the lithium metal capacity.”

Tesla’s new findings show that increased energy density is made possible with the hybrid concept. When combining lithium-ion cells with lithium metal, energy density improves as the graphite anode utilized in traditional lithium-ion cells is not capable of handling the increased energy. The utilization of a dual-salt electrolyte also increases density and decreases battery cell degradation.

Tesla’s battery researchers described the advantages of the hybrid lithium-ion/lithium metal cells in the discussion below.

“If an electric vehicle with a conventional lithium-ion battery can deliver a range of 400 km, then hybrid cells could enable a range of 480 km. By capping the upper cut-off voltage of hybrid cells to operate in lithium-ion mode, the average cell voltage and delivered capacity will decrease. As a result, operating a hybrid cell in lithium-ion mode delivers an energy density of 530Wh/L, about 25% less than a conventional lithium-ion cell.

“This would result in a range of 300 km. In a study of driving behavior for EVs, Smart et al.34 showed that only 1% of daily trips are longer than 325 km on average. Therefore, operating hybrid cells most of the time in lithium-ion mode enabling a range of 300 km, while periodically using the lithium metal portion for long > 400 km trips, as mimicked by this testing protocol, should be viable for most drivers.”

It should be noted that the Tesla battery researchers’ study is only in their initial stages. Thus, it may take some time before the technology gets rolled out to Tesla’s fleet. The wait would likely be worth it though, as the hybrid cells could open the door to all-electric vehicles with range extender features. This would be incredibly useful for electric vehicle owners who take long road trips with family, and it could also be a notable step towards EVs gaining range parity with their petrol-powered counterparts.

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Joey has been a journalist covering electric mobility at TESLARATI since August 2019. In his spare time, Joey is playing golf, watching MMA, or cheering on any of his favorite sports teams, including the Baltimore Ravens and Orioles, Miami Heat, Washington Capitals, and Penn State Nittany Lions. You can get in touch with joey at joey@teslarati.com. He is also on X @KlenderJoey. If you're looking for great Tesla accessories, check out shop.teslarati.com

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Elon Musk drops a Thanksgiving hint about Starship’s biggest test yet

Elon Musk says Starship Flight 15 will try to catch the ship itself, a first.

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Elon Musk says SpaceX’s next Starship flight will try something nobody has done before, by catching the ship itself. Speaking to roughly 2,000 people at the X Takeover event at Giga Texas on Saturday, Musk said Flight 15 is about four to six weeks away and “probably launches a little bit before Thanksgiving, is my guess.”

That is a slip from earlier reporting, which had pointed to a launch as early as October 19. Musk explained why the date keeps moving. “We’re making a bunch of improvements to the rocket between every flight,” he said, adding that there are often hundreds, sometimes thousands, of small changes. This time the list is short, “but some of them take a fair bit of work and we’ve got to go inside the tank to make some of these changes.”

“We’re going to try to catch the ship, which is a super big deal,” Musk said. “If we do so, that’ll be the first time that there’s been full recovery of an orbital class rocket.” SpaceX has already caught the Super Heavy booster with the tower’s mechanical arms, and has talked about catching the ship since late 2025, but the upper stage has never been caught.

Musk also laid out what comes after. “The next big milestone would be to refly both the booster and the ship,” he said, describing a Flight 16 where “all parts of an orbital rocket are reflown.”

The reason SpaceX wants this comes down to cost and cadence. Every Starship ship so far has ended its flight in the ocean, and SpaceX expects most of those water landings to end in fireballs. A ship that returns to Starbase intact can be inspected and flown again. SpaceX’s IPO filing, says Starship V3 is designed to deliver 100 metric tons to orbit in a fully reusable configuration, that SpaceX aims to cut the cost to reach orbit by 99% or more versus the historical average, and that tower catches should allow “multiple launches per day.”

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The payoff goes beyond cheaper launches. The next generation Starlink V3 satellites are too large for Falcon 9 and can only fly on Starship, which can carry up to 60 per flight. Flight 14 on September 28 deployed the first 26 of them after Starship reached orbit despite an early engine shutdown, as Teslarati reported. Musk blamed engine computer software, and said the heat shield “was extremely robust,” which he claimed in August had solved Starship’s biggest challenge.

NASA’s Moon plans depend on the same capability. NASA’s inspector general has described a lander mission that needs a propellant depot in low Earth orbit and more than 10 tanker flights, with SpaceX targeting one tanker launch every six days. That schedule only works if ships and boosters come back fast and fly again. Also, ship to ship propellant transfer has not been attempted yet.

One interesting hurdle yet to be explored is bringing the ship back to the launch site, with reentry over land, which will undoubtedly come with a lot of aviation safety reviews.

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Tesla’s mirrorless Cybercab will give riders a visibility upgrade

Tesla engineer confirms Cybercab update letting riders pull up rear and repeater cameras on demand.

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Tesla Cybercab camera visibility for passengers (Credit: Dan Burkland via X)
Tesla Cybercab camera visibility for passengers (Credit: Dan Burkland via X)

Tesla is working on a Cybercab update that would let passengers pull up the vehicle’s rear and side cameras on demand, and the request came straight from a rider.

The exchange played out on X late Friday. Cybercab rider Dan Burkland shared photos of the two-seater’s cabin screen after an evening ride, praised the UI team’s work, and left one request: let riders open the rear and repeater cameras whenever they want, “especially for peace of mind.” Tesla UI software engineer Evan (@CarCoder) answered with two words: “In development.”

The idea fits a pattern Teslarati has tracked since public rides began. Days after paid Cybercab service opened in Austin, Tesla sent riders a survey that asked them to rate the touchscreen, the app and the cabin, and to pick the features they wanted most. We reported on that survey in September, and a camera view is the kind of small software change Tesla can push quickly if riders keep asking.

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It also speaks to something unique about the vehicle. With no steering wheel, no pedals and no driver, passengers have no mirror to check and no way to see behind them. The hardware is clearly built for camera awareness, from the repeater cameras to the rear camera. Letting a passenger look through those same cameras would give a nervous first time rider a way to confirm what is around the car.

The timing matters because the fleet is growing fast. Tesla’s Robotaxi account said on Saturday that more than 300 Cybercabs are now serving Austin, an eightfold increase in 30 days, and Tesla AI chief Ashok Elluswamy named Dallas as the next city. More cars and more cities mean more people riding in a driverless vehicle for the first time, which is exactly when small trust features carry weight.

For now, the feature is confirmed only as in development. If Tesla follows its usual pattern with Cybercab software, riders could see it appear in a point release without any announcement, and Teslarati will watch for it.

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Tesla’s Cybercab fleet jumped 8x in a month, with Dallas up next

Tesla confirms its first official Cybercab fleet number as Austin scales fast and Dallas looms.

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Tesla says more than 300 Cybercabs are now serving Austin, the first time the company has put an official number on its active Cybercab fleet. The figure came from the Robotaxi account on X on Saturday, which wrote that one month after launch the service had “scaled to 300+ Cybercabs serving Austin – an 8x increase in 30 days.”

Ashok Elluswamy, Tesla’s head of AI software, quoted the post with a line that carried the bigger news. “Two years since the 10/10 Cybercab WeRobot event, the cabs are everywhere in Austin now. Dallas soon,” he wrote. It is the first time Tesla has named the next city for public Cybercab rides.

Tesla opened Cybercab rides to the public in Austin on September 4, as Teslarati reported, a day after an invite only launch event. The ramp since then has been steep. Our September 28 report had the fleet at well over 100 units after availability jumped from 58 to 125 in a single week. On Thursday, Tesla added 150 Cybercabs to the Texas automated vehicle registry, lifting its registered count to 319 from 169. The first seven appeared on the registry on August 31.

RobotaxiTracker, a community site that counts vehicles from sightings and state records, listed 275 vehicles in unsupervised service in Austin on Saturday, 105 of them Cybercabs, which is well below Tesla’s figure. Tracker counts can lag official numbers, though Sawyer Merritt noted that Cybercab wait times in Austin stayed short on Saturday evening even with more than 2,000 fans in town for X Takeover.

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Regulators are watching the rollout. NHTSA opened an audit query into Tesla’s certification that the Cybercab meets federal safety standards, and sworn answers are due October 30. Tesla reports third quarter earnings on October 21, which gives the company a natural venue to define its fleet numbers and put a date on Dallas.

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