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.
Lifestyle
Tesla FSD changed its mind mid-intersection, and it may have saved a life
Tesla shares dashcam footage of FSD Supervised stopping mid intersection to avoid a T-bone crash.
Tesla is putting another Full Self-Driving save in front of its 24.8 million followers on X.
On Tuesday morning, Tesla’s main account shared a dashcam clip with the caption “FSD Supervised preventing T-bone crash.” The footage came from an owner posting as TheNewGrid, who described what happened at a stop sign: “I looked at the car coming to the stop sign figured they would stop, my car went, then came to a stop mid intersection as they flew by. Had I been manually driving this would have resulted in a crash.”
The sequence is the notable part. FSD had already started crossing when the other driver ran the stop sign. Instead of pressing on, the car braked hard in the middle of the intersection and let the crossing vehicle pass in front of it. By the owner’s own account, they had made the same assumption the software initially made, that the other car would stop, and would not have corrected in time.
FSD Supervised preventing T-bone crash
— Tesla (@Tesla) October 6, 2026
The clip is the latest in a run of safety posts Tesla has amplified over the past several days. On Saturday, the company shared a video from Selling Sunset star Jason Oppenheim, who sold his Bentley for a Model Y and said he was buying Teslas with FSD for 10 of his employees. Ashok Elluswamy, who leads Tesla AI, followed up by writing that Tesla self-driving “reacts to other people cutting into your path with super-human response times.” On Monday, a Cybertruck owner posted footage of FSD moving across three lanes from a red light to clear a path for an ambulance approaching from behind.
This recent clip also lands a few weeks after Tesla began shipping Automatic Collision Evasion with FSD v14.3.9, a feature that can activate FSD on the driver’s behalf when a frontal collision is imminent or the driver appears distracted. Elluswamy said in September that “even earlier prediction of hazards, even faster reaction time and overall significantly better safety and collision avoidance” are coming with v15, the release Tesla has tied to round the clock Robotaxi operation.
The safety messaging matters beyond social media. Tesla has said FSD Supervised was 4.1 times less likely to crash than manual driving across 100 million kilometers on European roads, and it has been putting those figures in front of regulators. Eight EU countries have now approved FSD Supervised, with Croatia the most recent, but the EU’s bloc-wide vote originally set for October 6 has been pushed to December at the earliest.
FSD Supervised is still a Level 2 system, and the driver remains responsible at all times. Even heavy users find reasons to step in. Teslarati’s Joey Klender, who uses FSD for about 76 percent of his driving, laid out five recurring issues on Tuesday that still prompt him to intervene. Clips like this one show the other column of that ledger: moments where the software caught a mistake a human was about to make.
Energy
Tesla Model 3 and Model Y can now do what only Cybertruck could
Tesla Model 3 and Model Y can power your home with Powerwall 3 during outages.
Tesla has turned its two top sellers into backup batteries for the house.
Tesla Energy announced on Tuesday that Powershare Home Backup is now available for new Model 3 and Model Y vehicles paired with a Powerwall 3, saying the car can “extend your home backup by over 2 days.” Minutes later, Tesla’s main account quoted the post with a broader pitch: “With Powerwall 3, every Tesla can now serve as your home’s backup battery.”
Until this week, the Cybertruck was the only Tesla that could send power back into a home, and that capability only began working alongside Powerwall 3 last month, after years of ambitious targets.
Tesla’s updated Powershare page says every Model 3 and Model Y ordered in the U.S. or Puerto Rico on or after October 1, 2026 can use the feature. Some, but not all, earlier cars also qualify. Owners can check on the touchscreen under Software, then Additional Vehicle Information, where a capable car shows “Powershare Support: Enabled.” As Electrek reported, bidirectional power on the two cars runs through an inverter Tesla calls PCS2 Lite, and the company has not said when that part entered production on each trim.
The home side is simpler. A house that already has a Powerwall 3 and either a Wall Connector 3 or Universal Wall Connector needs no additional equipment, and Tesla says compatibility is enabled through a software update. When the grid drops, the Powerwall and the car work together, with up to 11.52 kW of continuous power available. Tesla’s “over two days” estimate assumes a home using 30 kWh per day and a car starting at a 90 percent charge. Standard trims are rated for up to two days, while the Cybertruck adds more than three.
There are limits. Powerwall 2 and Powerwall+ support is listed as “coming soon.” Model S and Model X are not included, and Grid Support, the program that lets Cybertruck owners in Texas send power back to the grid during demand spikes for bill credits, is not available for Model 3 or Model Y.
The rollout also lines up with something Elon Musk said more than three years ago. At Tesla’s March 2023 Investor Day, Musk said, “I don’t think very many people are going to want to use bidirectional charging, unless you have a Powerwall.” Tesla has now shipped the feature for its volume cars with exactly that requirement attached.
The Powerwall pairing was the hard part on Cybertruck. Tesla told owners in December 2025 that Powershare with Powerwall had been pushed to mid 2026, and lead engineer Wes Morrill explained that two devices capable of forming a home’s grid have to negotiate which one leads during an outage, across multiple generations of hardware. With that work done for the truck, Tesla was able to extend it to the Model 3 and Model Y within a month.
Ford and GM have offered home backup from their EVs for several years, but both require a separate inverter and backup hardware. Tesla’s version leans on equipment many Powerwall 3 owners already have on the wall. Powershare for the two cars also ships as part of software update 2026.38.3, the same release that began delivering Halloween Mode on Tuesday.
Tesla is now starting to ship a “Halloween Mode” that is filled with some creepy and fun features; the company says, “This spooky update turns your Tesla into a haunted house on wheels.”
The update is just the latest in a series of updates that Tesla typically ships out in a seasonal fashion. The Spring and Summer Updates provided some fun novelty items while also packing some cool features that are actually useful for the ownership experience.
This one seems to be more fun-forward, and there are not any updates to the Full Self-Driving suite or overall operation of the vehicle. Instead, these novelty features are geared toward getting you in the mood for the Fall and Halloween.
Halloween Mode now rolling out 🎃
This spooky update turns your Tesla into a haunted house on wheels
– Ghost costume on your car’s avatar
– Enable Trick or Treat to play spooky sounds & flicker the lights when visitors approach
– New haunting light show, wraps & lock sound
– A rather chilling Photobooth
– Frighten people remotely by speaking through the app…your car will say it in a voice of its own
Side effects may include neighborhood notoriety
— Tesla (@Tesla) October 6, 2026
New Ghost Costume on Car Avatar
Driver Visualization will now show your vehicle as a ghost, as an all-white sheet is draped over the vehicle. Pedestrians are turned into mummies or skeletons, and other vehicles are all a spooky green:
Credit: Tesla
Additionally, the Park Scene with your Tesla now displays that ghost costume draped over your vehicle in the foreground of a scary backdrop with Jack-o-Lanterns and a haunted house:
Credit: Tesla
Trick or Treat Mode
Trick or Treat Mode will enable the vehicle to play spooky sounds and flicker the lights as visitors approach. This might be a nice touch for when you’re handing out candy to kids on Halloween Night.
Other Features
Tesla is also adding a new Light Show, new Wrap Options, and a new Lock Sound with this update.
Credit: Tesla
Additionally, Photobooth has a new Halloween option:
Credit: Tesla
You will also be able to speak remotely through the app and transmit your voice to people outside, which is not a new feature, but the car will say it in a voice of its own, which is a new feature with that bullhorn-like feature.
Tesla FSD changed its mind mid-intersection, and it may have saved a life
Tesla Model 3 and Model Y can now do what only Cybertruck could
