Tesla’s Battery Day detailed a variety of topics that are related to the future of cell manufacturing efficiency. However, the presentation also showed how the automaker is improving the design of its vehicles by utilizing a new battery architecture. Tesla plans to adopt the same strategy within its vehicles to improve mass, range, and the structural integrity of its vehicles.
Teslarati reported earlier this year that Tesla would be using a single-piece casting design on the Model Y. The improved casting eliminates 79 parts per car, which not only increases manufacturing efficiency but also increases safety for drivers. The cost of each vehicle’s rear underbody design also decreases by 40% thanks to the casting, which is performed by a massive machine known as the Giga Press.
The single-piece rear casting is made from Tesla’s own high-pressure aluminum alloy that has a high strength thanks to no heat treatment or coatings that would take away from the structural integrity of the design. Heat treating a casting of this size after manufacturing causes deformation, CEO Elon Musk said during the event.
However, the manufacturing team at Tesla also drew inspiration from aircraft wings to improve the structural integrity of its vehicles. While the casting improves manufacturing efficiency and strength, the positioning of structural batteries eliminates excess structure from the battery packs, increasing density.
“The non-cell portion of the battery has negative mass,” Musk said. “We saved more mass in the rest of the vehicle than in the non-cell portion of the battery. So how do you really minimize the mass of the battery? Make it negative.”
The minimization of negative mass allowed the automaker to increase the density of the battery pack. Individual cells could be positioned more efficiently because excessive structures within the pack itself were eradicated. The new Tesla battery design is completely free of any negative mass, which improves pack density along with structural integrity.
“The pack itself is structural,” Musk stated.
Additionally, the filler within the Model 3 and Model Y packs, which currently uses a flame retardant, now uses a structural adhesive and flame retardant. This adhesive effectively attaches the cells to the top and bottom sheets of the pack. “This allows you to do sheer transfer between the upper and lower sheet,” which increases stiffness and prevents major deformation in the event of a crash.
Improvements in the casting design of Tesla’s future cars and the newly designed battery architecture, which uses new materials and strategies to increase stiffness, will increase the already safe vehicles that the company manufactures. Tesla already holds three separate five-star crash safety ratings with the Model S, Model 3, and Model X. The Model Y has not yet been tested, but the vehicle does use the one-piece rear casting design already at the Fremont production facility.
Tesla’s Battery Day did not disappoint. While the blueprint to cell manufacturing efficiency was laid out, the company also showed how battery layout and architecture could increase Tesla’s vehicle safety. The new design revolutionizes EVs as a whole and will eventually lead to more safety than previously displayed.
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Tesla Model Y dominated China’s NEV sales in December 2025
As per sales data from China, the all-electric crossover finished first among the country’s best-selling EVs and plug-in hybrids.
The Tesla Model Y ranked as China’s top-selling new energy vehicle in December, leading an intensely competitive market packed with strong domestic brands.
As per sales data from China, the all-electric crossover finished first among the country’s best-selling EVs and plug-in hybrids. The Model 3 also placed within the country’s top ten vehicles.
Model Y leads China’s NEV rankings
The graphic, shared on X and sourced from Chinese auto industry data aggregator Yiche, listed the top 20 best-selling new energy vehicles in China for December. Tesla’s Model Y claimed the No. 1 position with roughly 65,874 units sold, finishing well ahead of a field dominated by domestic manufacturers such as BYD, SAIC-GM-Wuling, and Xiaomi.
The chart also showed strong performances from other high-volume models, including BYD’s Qin Plus, which sold 46,837 units during the month. Tesla’s Model 3 ranked eighth overall, with just under 28,000 units sold, placing it ahead of numerous locally produced competitors despite its rather premium price.
Tesla China’s strong December
Tesla China had a stellar December 2025. During the month, Tesla sold 97,171 vehicles wholesale in China, as per data from the China Passenger Car Association (CPCA). The result marked Tesla China’s second-highest monthly total on record, trailing only November 2022’s peak of 100,291 units.
December’s wholesale figure represented a 3.63% increase from the same month a year earlier and a 12.08% jump from November. Industry watchers have suggested that part of the surge was driven by Tesla pulling deliveries forward to allow customers to benefit from more favorable purchase tax policies before year-end.
Despite this, December’s results suggest that Tesla’s Model Y and Model 3 remain highly competitive offerings in China, which is extremely impressive considering the competition from domestic players and their still premium price.
Elon Musk
Elon Musk’s net worth is nearing $800 billion, and it’s no small part due to xAI
A newly confirmed $20 billion xAI funding round valued the business at $250 billion, adding an estimated $62 billion to Musk’s fortune.
Elon Musk moved within reach of an unprecedented $800 billion net worth after private investors sharply increased the valuation of xAI Holdings, his artificial intelligence and social media company.
A newly confirmed $20 billion funding round valued the business at $250 billion, adding an estimated $62 billion to Musk’s fortune and widening his lead as the world’s wealthiest individual.
xAI’s valuation jump
Forbes confirmed that xAI Holdings was valued at $250 billion following its $20 billion funding round. That’s more than double the $113 billion valuation Musk cited when he merged his AI startup xAI with social media platform X last year. Musk owned roughly 49% of the combined company, which Forbes estimated was worth about $122 billion after the deal closed.
xAI’s recent valuation increase pushed Musk’s total net worth to approximately $780 billion, as per Forbes’ Real-Time Billionaires List. The jump represented one of the single largest wealth gains ever recorded in a private funding round.
Interestingly enough, xAI’s funding round also boosted the AI startup’s other billionaire investors. Saudi investor Prince Alwaleed Bin Talal Alsaud held an estimated 1.6% stake in xAI worth about $4 billion, so the recent funding round boosted his net worth to $19.4 billion. Twitter co-founder Jack Dorsey and Oracle co-founder Larry Ellison each owned roughly 0.8% stakes that are now valued at about $2.1 billion, increasing their net worths to $6 billion and $241 billion, respectively.
The backbone of Musk’s net worth
Despite xAI’s rapid rise, Musk’s net worth is still primarily anchored by SpaceX and Tesla. SpaceX represents Musk’s single most valuable asset, with his 42% stake in the private space company estimated at roughly $336 billion.
Tesla ranks second among Musk’s holdings, as he owns about 12% of the EV maker’s common stock, which is worth approximately $307 billion.
Over the past year, Musk crossed a series of historic milestones, becoming the first person ever worth $500 billion, $600 billion, and $700 billion. He also widened his lead over the world’s second-richest individual, Larry Page, by more than $500 billion.
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Tesla Cybercab sighting confirms one highly requested feature
The feature will likely allow the Cybercab to continue operating even in conditions when its cameras could be covered with dust, mud, or road grime.
A recent sighting of Tesla’s Cybercab prototype in Chicago appears to confirm a long-requested feature for the autonomous two-seater.
The feature will likely allow the Cybercab to continue operating even in conditions when its cameras could be covered with dust, mud, or road grime.
The Cybercab’s camera washer
The Cybercab prototype in question was sighted in Chicago, and its image was shared widely on social media. While the autonomous two-seater itself was visibly dirty, its rear camera area stood out as noticeably cleaner than the rest of the car. Traces of water were also visible on the trunk. This suggested that the Cybercab is equipped with a rear camera washer.
As noted by Model Y owner and industry watcher Sawyer Merritt, a rear camera washer is a feature many Tesla owners have requested for years, particularly in snowy or wet regions where camera obstruction can affect visibility and the performance of systems like Full Self-Driving (FSD).
While only the rear camera washer was clearly visible, the sighting raises the possibility that Tesla may equip the Cybercab’s other external cameras with similar cleaning systems. Given the vehicle’s fully autonomous design, redundant visibility safeguards would be a logical inclusion.
The Cybercab in Tesla’s autonomous world
The Cybercab is Tesla’s first purpose-built autonomous ride-hailing vehicle, and it is expected to enter production later this year. The vehicle was unveiled in October 2024 at the “We, Robot” event in Los Angeles, and it is expected to be a major growth driver for Tesla as it continues its transition toward an AI- and robotics-focused company. The Cybercab will not include a steering wheel or pedals and is intended to carry one or two passengers per trip, a decision Tesla says reflects real-world ride-hailing usage data.
The Cybercab is also expected to feature in-vehicle entertainment through its center touchscreen, wireless charging, and other rider-focused amenities. Musk has also hinted that the vehicle includes far more innovation than is immediately apparent, stating on X that “there is so much to this car that is not obvious on the surface.”
Tesla Model Y dominated China’s NEV sales in December 2025
Elon Musk’s net worth is nearing $800 billion, and it’s no small part due to xAI
