News
Tesla battery researchers open path to all-electric range extender concept
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.
“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.
Investor's Corner
New drone video shows Tesla’s Optimus Factory reaching a turning point
New drone footage shows Tesla’s dedicated Optimus factory steel frame nearing completion at Giga Texas.
Tesla’s dedicated Optimus factory at Gigafactory Texas is closing in on a finished steel frame, according to drone footage posted Thursday afternoon by longtime site observer Joe Tegtmeyer. In the video, Tegtmeyer said structural steel assembly is now about five column grids away from reaching the building’s north perimeter beam, putting the primary skeleton in its final stretch roughly six months after Tesla broke ground on the North Campus site in late March.
The Giga Texas Optimus Factory latest update … construction keeps moving fast!
Steel assembly is now only about 5 column grids from the north perimeter beam. Concrete is going in on the three upper floors, rebar is still being laid for more pours, and footing / grade-beam work… pic.twitter.com/qvFPvwnYzW
— Joe Tegtmeyer 🚀 🤠🛸😎 (@JoeTegtmeyer) September 17, 2026
Tegtmeyer’s footage shows concrete already going in on three upper floors while crews continue laying rebar and pouring grade beam footings at ground level. That kind of parallel work, steel rising at one end of the site while concrete sets at the other, is a scheduling approach Tesla used at the original Giga Texas building and appears to be repeating here to save time before the plant’s targeted 2027 production start.
Teslarati has tracked the building’s progress since Tesla confirmed construction was officially underway in May, when the first steel structure went up on what was then bare, reclaimed land. The facility is part of a more than 5.2 million square foot expansion of Giga Texas’s North Campus that Tesla has said will eventually run nearly the length of the existing vehicle factory, over 4,000 feet, while sitting somewhat narrower. Musk has pegged the long term output target at 10 million Optimus units a year once the line is running at full capacity, a volume that would dwarf the one million unit pilot line Tesla is standing up separately at its Fremont, California factory.
Tesla Giga Texas to feature massive Optimus V4 production line
The Texas facility sits alongside another major buildout on the same campus. Terafab, the joint Tesla and SpaceX chip fabrication plant that will eventually supply the silicon running Optimus units in the field. Housing robot assembly and chip production on the same grounds is a deliberate supply chain decision, cutting down on the shipping and lead time that would otherwise sit between the two.
Tesla has not given an updated timeline beyond its previously stated goal of bringing high volume Optimus production online at the site in the summer of 2027. Fremont’s smaller pilot line began mass producing the current Gen 3 robot in January, with that plant expected to build tens of thousands of units this year primarily to generate the real world data Tesla needs to refine the robot’s software before Giga Texas ramps up. Six months of visible construction progress, tracked almost entirely through Tegtmeyer’s recurring drone flights, gives the clearest outside look yet at how seriously Tesla is treating that 2027 deadline.
Investor's Corner
Tesla and SpaceX take “Terafab” Trademark fight to Federal Court
Tesla and SpaceX sue a small Illinois firm after cease and desist letters over Terafab.
Tesla and SpaceX are asking a federal judge to rule that their planned Terafab chip factory does not infringe a small Illinois company’s trademark, a request that arrives only after months of quiet negotiation broke down this summer.
The dispute traces to May 18, when Tesla filed three U.S. trademark applications for “Terafab” and “Tesla Terafab,” covering semiconductor chips and related chip making services. TERA-print LLC, a nanotechnology company that has held a federal trademark for “Tera-Fab” since 2021, responded five days later with a cease and desist letter. According to the lawsuit, first reported by Reuters, TERA-print argued that Tesla and SpaceX’s use of “Terafab” would confuse consumers familiar with its own trademark, which covers a desktop photolithography printer sold to researchers for sensor and bioengineering work.
What stands out in the filing is the timing of TERA-print’s own paperwork. One day before sending that cease and desist letter, on May 22, TERA-print applied to expand its existing registration to cover semiconductor materials, silicon chips, nanoelectronic devices and AI design services, categories it had not previously claimed. Tesla and SpaceX call that filing opportunistic in their complaint, noting it arrived two months after Tesla’s public Terafab announcement and just days after Tesla’s own trademark applications went in.
Elon Musk launches TERAFAB: The $25B Tesla-SpaceXAI chip factory that will rewire the AI industry
By June 10, TERA-print was threatening to sue for federal trademark infringement, false designation of origin and unfair competition, the complaint states. Rather than wait to be sued, Tesla, SpaceX and SpaceXAI met with TERA-print six separate times between June and August trying to resolve the dispute directly. Those talks collapsed, and the companies filed for declaratory judgment this week in the U.S. District Court for the Western District of Texas, asking a judge to find that “Terafab” does not infringe TERA-print’s mark before TERA-print can file a claim of its own.
TERA-print isn’t backing down. The company told PCMag it discussed a settlement with Tesla as recently as September 2 and feels misled by what it called Tesla’s professed interest in settling. Its CTO, Andrey Ivankin, said TERA-print holds a Defense Department contract to fabricate semiconductors and partially owns Mattiq Inc., an AI company built on TERA-print’s products, and that the company will vigorously defend its rights.
Tesla and SpaceX argue the overlap is superficial. Terafab is planned as a $16.8 billion complex spanning roughly 100 million square feet at the Grimes County site SpaceX confirmed last month, built to produce chips for Optimus robots, Tesla’s AI computing needs and SpaceX’s orbital data center ambitions, a scale and purpose the companies say no reasonable consumer would confuse with a tabletop lab printer. TERA-print’s product line has stayed focused on lithography tools for biological and sensor research since it registered its mark in 2021.
The trademark fight is the second legal dispute tied to the Terafab project in the past week, following a separate SpaceX suit aimed at keeping company records about the facility out of public view, as KBTX reported. Whether construction proceeds under the Terafab name now depends on a federal judge in Austin.
News
NHTSA just escalated its Tesla Cybercab investigation in a big way
NHTSA escalated its Cybercab audit into a sworn Special Order with a September 30 deadline.
Federal regulators have moved from asking Tesla questions about its Cybercab to demanding sworn answers. The National Highway Traffic Safety Administration issued a Special Order that requires a Tesla officer to sign an affidavit attesting to the completeness of the company’s responses, with a deadline of September 30.
The order builds on Audit Query AQ26002, which NHTSA opened on September 3, the same day Tesla began commercial Cybercab service in Austin. Teslarati covered that initial inquiry when it surfaced, noting the agency wanted to understand how Tesla certified a vehicle with no permanently attached steering wheel, pedals, or mirrors as compliant with Federal Motor Vehicle Safety Standards. A Special Order is a different tool and converts a fact finding review into a legally enforceable demand, the same mechanism NHTSA used against Tesla in 2023 during its Autopilot investigation.
Several of the 21 requests target a specific gap in Cybercab’s design. One asks whether Tesla used temporarily attached human controls at any point to help certify the vehicle, and if so, which standards depended on that equipment being present. Another quotes an existing rule directly: “The service brakes shall be activated by means of a foot control.” Cybercab has no foot pedal. NHTSA wants a detailed explanation of how the vehicle satisfies that requirement, and how it complies without the kind of exemption granted to Zoox in July under Part 555, the regulatory pathway built for steering wheel free vehicles.
The order does not claim Cybercab is unsafe or that Tesla broke a rule. It requires Tesla to explain, under oath, the reasoning behind decisions the company already made when it self-certified the vehicle. That distinction matters, but so does the exposure. Motor1’s reporting, summarized here, put potential civil penalty exposure as high as $139 million if NHTSA later finds the certification was flawed, on top of whatever criminal risk comes with a false sworn statement.
Tesla has not said publicly how it plans to respond. Cybercab is still carrying passengers in Austin through the Robotaxi app while the September 30 deadline approaches, and the company has continued expanding the vehicle’s footprint even as the regulatory question remains open. The Special Order does not pause any of that and just sets a date by which Tesla has to put its certification logic on the record, with a company officer’s name attached to it.
New drone video shows Tesla’s Optimus Factory reaching a turning point
Tesla and SpaceX take “Terafab” Trademark fight to Federal Court
