Tesla’s Battery Day is coming tomorrow after the electric car maker’s 2020 Annual Shareholder Meeting. During the event, Tesla is expected to discuss the details of its next-generation battery cells, as well as their role in the world’s acceleration in sustainable energy. Actual details about Battery Day have been pretty scarce save for a few potential leaks, but that has not stopped the Tesla community from speculating about what the highly-anticipated event would involve.
A concise summary of the current expectations for Battery Day was recently shared by Tesla Daily’s Rob Maurer, who compiled a list of topics that the electric car maker could cover during the event. Following then is a list of expectations about what Tesla could discuss tomorrow, as the company finally shows the world what it has been working on with regards to its battery technology.
A New Cell Design
Tesla has been teasing that it would be going into the production of battery cells. So far, leaks suggest that the company is about to adopt a larger form factor for its batteries, similar to how Tesla introduced the 2170 cells for the Model 3, which were larger than the 18650 cells used in the Model S and Model X. Leaks have pointed to Tesla’s new cells possibly adopting a 54×98 form factor, which has about 10x the volume of a 2170 cell.
With larger form factors, the electrons and the ions travel larger distances as they move around in the cell, generating more friction and heat. This is a huge downside to larger cells, but Tesla’s tabless battery patent may hold the key to solving this issue. With a tabless battery cell design, the distance traveled by electrons and ions is largely reduced, limiting the disadvantages inherent among large cells. Such a design has several advantages, including better energy density and a more efficient manufacturing process.
Battery Chemistry
Speculations are abounding that Tesla may discuss the amount of silicon that it is using in the anode of its next-generation cells. The more silicon that is used, the better the energy density. However, the utilization of silicon usually results in cracked anodes over time, reducing battery performance and life. Introducing more silicon into the anode is something that battery researchers have been attempting to accomplish for a while now, so it would be quite interesting if the electric car maker would announce some headway into its silicon use as well.
Tesla may also discuss Maxwell’s technology and how it is being used for the company’s electric cars and energy storage devices. Maxwell has developed numerous innovations prior to its acquisition by Tesla, though the most relevant part of the company’s work in relation to the electric car maker is arguably its dry battery electrode tech. Considering that traditional lithium-ion batteries produce their electrodes in a wet slurry format (a rather lengthy process), dry electrode technology could vastly improve not only the energy density of Tesla’s cells, they could improve the production output of the batteries themselves as well.
Cell-to-Pack Innovations
Tesla’s battery packs today feature cells that are packed into modules that are then packed into a battery pack. Back in the days of the original Roadster, battery modules were used as a means for the company to take out parts of the battery that may need to be replaced without taking out the entire pack. That was 12 years ago, however, and much has happened since then. Tesla has transitioned from a budding niche electric car maker to the manufacturer of the market’s best-selling EVs.
As Elon Musk noted in the past, battery modules today are pretty much just an extra step, taking up weight without really serving a legitimate purpose. Musk then stated that the future is cell to pack without modules, suggesting that the company’s next-generation batteries will be using a cell-to-pack design. Such an innovation gives numerous benefits to Tesla, from lower production costs to possibly even better energy density.
Battery Manufacturing and the Roadrunner Line
Elon Musk has always been pretty transparent about Tesla’s mission, which is to accelerate the advent of sustainable energy. Having enough batteries to enable such a transition is key to this goal. With this in mind, the potential innovations that Tesla will be discussing in Battery Day — a larger form factor that would allow the company to produce fewer cells to get the same amount of energy; a tabless cell design that could make production easier; dry electrode tech that could greatly increase the production capacity density of each battery; and a cell-to-pack design that should allow the production of batteries with less equipment at less cost — could ultimately pave the way for electric vehicles and energy storage products that are significantly better than the industry standard today.
The Roadrunner project in Fremont is expected to be a central component of Tesla’s battery manufacturing plans, with attendees to the event being shown just how fast the company could produce its battery cells using its in-house production process. Elon Musk seems to be hyping the Roadrunner line recently on Twitter as well, when he made references to a game called “Factorio,” which happens to be a title focused on growing and maintaining advanced, efficient factories.
The Million-Mile Battery
The million-mile battery has been heavily speculated for Battery Day. Tesla’s electric cars are already capable of lasting long despite heavy use, but with batteries and powertrains that could last a million miles, the company could create a generation of vehicles that are designed to be always operational for an extended period of time. Million-mile batteries are then crucial for Tesla’s plans to roll out a Robotaxi service, which involves vehicles traveling long distances every year.
The Plaid Powertrain
With Tesla’s battery innovations in mind, speculations are high that the company would unveil its first vehicles that would carry its next-generation cells on Battery Day. Among Tesla’s ongoing projects, the Roadrunner cells seem to be a perfect match for cars like the Plaid Model S, Plaid Model X, and next-generation Roadster. All three vehicles have been confirmed by Elon Musk to feature the company’s upcoming “Plaid Powertrain,” which is something that has been heavily teased for some time now. Interestingly enough, updates on Tesla’s Plaid vehicles have been pretty scarce lately, making an announcement on Battery Day somewhat likely.
Watch Rob Maurer’s full Tesla Battery Day predictions in the video below.
News
Tesla hints at Starlink integration with recent patent
“By employing polymer blends, some examples enable RF transmission from all the modules to satellites and other communication devices both inside and outside the vehicle.”
Tesla hinted at a potential Starlink internet terminal integration within its vehicles in a recent patent, which describes a vehicle roof assembly with integrated radio frequency (RF) transparency.
The patent, which is Pub. No U.S. 2025/0368267 describes a new vehicle roof that is made of RF-transparent polymer materials, allowing and “facilitating clear communication with external devices and satellites.”
Tesla believes that a new vehicle roof design, comprised of different materials than the standard metallic or glass elements used in cars today, would allow the company to integrate modern vehicular technologies, “particularly those requiring radio frequency transmission and reception.
Tesla has recently filed a US patent application on integrating RF transparent materials into the roof structure.
“facilitating clear communication with external devices and satellites”
Tesla fleet is getting @Starlink connectivity integration soon. LFG @Tesla @elonmusk… pic.twitter.com/bLa8YtPLd1
— Chansoo Byeon (@Chansoo) December 9, 2025
Instead of glass or metallic materials, Tesla says vehicles may benefit from high-strength polymer blends, such as Polycarbonate, Acrylonitrile Butadiene Styrene, or Acrylonitrile Styrene Acrylate.
These materials still provide ideal strength metrics for crashworthiness, stiffness for noise, vibration, and harshness control, and are compliant with head impact regulations.
They would also enable better performance with modern technologies, like internet terminals, which need an uninterrupted signal to satellites for maximum reception. Tesla writes in the patent:
“By employing polymer blends, some examples enable RF transmission from all the modules to satellites and other communication devices both inside and outside the vehicle.”
One of the challenges Tesla seems to be aware of with this type of roof design is the fact that it will still have to enable safety and keep that at the forefront of the design. As you can see in the illustration above, Tesla plans to use four layers to increase safety and rigidity, while also combating noise and vibration.
It notes in the patent that disclosed examples still meet the safety requirements outlined in the Federal Motor Vehicle Safety Standards (FMVSS).
Starlink integrated directly into Tesla vehicles would be a considerable advantage for owners. It would come with a handful of distinct advantages.
Initially, the inclusion of Starlink would completely eliminate cellular dead zones, something that is an issue, especially in rural areas. Starlink would provide connectivity in these remote regions and would ensure uninterrupted service during road trips and off-grid adventures.
It could also be a critical addition for Robotaxi, as it is crucial to have solid and reliable connectivity for remote monitoring and fleet management.
Starlink’s growing constellation, thanks to SpaceX’s routine and frequent launch schedule, will provide secure, stable, and reliable internet connectivity for Tesla vehicles.
Although many owners have already mounted Starlink Mini dishes under their glass roofs for a similar experience, it may be integrated directly into Teslas in the coming years, either as an upgrade or a standard feature.
News
Tesla supplements Holiday Update by sneaking in new Full Self-Driving version
It seems Tesla was waiting for the Hardware 4 rollout, as it wanted to also deploy a new Full Self-Driving version to those owners, as it appeared in the release notes for the Holiday Update last night.
Tesla has surprised some owners by sneaking in a new Full Self-Driving version with the wide release of the Holiday Update, which started rolling out to Hardware 4 owners on Friday night.
Tesla has issued a controlled and very slow release pattern with the Holiday Update, which rolls out with Software Version 2025.44.25.5.
For the past two weeks, as it has rolled out to Hardware 3 and older Tesla owners, the company has kept its deployment of the new Software Version relatively controlled.
It seems Tesla was waiting for the Hardware 4 rollout, as it wanted to also deploy a new Full Self-Driving version to those owners, as it appeared in the release notes for the Holiday Update last night.
Tesla Full Self-Driving v14.2.1.25 made its first appearance last night to Hardware 4 owners who are members of the Early Access Program (EAP). It appears to be a slight refinement from FSD v14.2.1, which has been out for a couple of weeks.
Tesla v2025.44.25.5 Holiday update incoming
Also Full Self-Driving v14.2.1.25!!! pic.twitter.com/74D7S0UGXz
— TESLARATI (@Teslarati) December 13, 2025
Many owners welcome the new FSD version, us included, because we’ve been less than impressed with v14.2.1. We have experienced some minor regressions with v14.2.1, especially with Speed Limit recognition, Speed Profile tinkering, and parking performance.
As it stands, Full Self-Driving is still particularly impressive, but Tesla is evidently having an issue with some of the adjustments, as it is still refining some of the performance aspects of the suite. This is expected and normal with some updates, as not all of them are an improvement in all areas; we routinely see some things backtrack every once in a while.
This new FSD version is likely to take care of those things, but it also includes all of the awesome Holiday Update features, which include:
- Grok with Navigation Commands (Beta) – Grok will now add and edit destinations.
- Tesla Photobooth – Take pictures inside your car using the cabin-facing camera
- Dog Mode Live Activity – Check on your four-legged friend on your phone through periodic snapshots taken of the cabin
- Dashcam Viewer Update – Includes new metrics, like steering wheel angle, speed, and more
- Santa Mode – New graphics, trees, and a lock chime
- Light Show Update – Addition of Jingle Rush light show
- Custom Wraps and License Plates – Colorizer now allows you to customize your vehicle even further, with custom patterns, license plates, and tint
- Navigation Improvements – Easier layout and setup
- Supercharger Site Map – Starting at 18 pilot locations, a 3D view of the Supercharger you’re visiting will be available
- Automatic Carpool Lane Routing – Navigation will utilize carpool lanes if enabled
- Phone Left Behind Chime – Your car will now tell you if you left a phone inside
- Charge Limit Per Location – Set a charge limit for each location
- ISS Docking Simulator – New game
- Additional Improvements – Turn off wireless charging pad, Spotify improvements, Rainbow Rave Cave, Lock Sound TRON addition
Tesla also added two other things that were undocumented, like Charging Passport and information on USB drive storage to help with Dashcam.
Tesla is updating Cybertruck owners on its timeline of a massive feature that has yet to ship: Powershare with Powerwall.
Powershare is a bidirectional charging feature exclusive to Cybertruck, which allows the vehicle’s battery to act as a portable power source for homes, appliances, tools, other EVs, and more. It was announced in late 2023 as part of Tesla’s push into vehicle-to-everything energy sharing, and acting as a giant portable charger is the main advantage, as it can provide backup power during outages.
Cybertruck’s Powershare system supports both vehicle-to-load (V2L) and vehicle-to-home (V2H), making it flexible and well-rounded for a variety of applications.
However, even though the feature was promised with Cybertruck, it has yet to be shipped to vehicles. Tesla communicated with owners through email recently regarding Powershare with Powerwall, which essentially has the pickup act as an extended battery.
Powerwall discharge would be prioritized before tapping into the truck’s larger pack.
However, Tesla is still working on getting the feature out to owners, an email said:
“We’re writing to let you know that the Powershare with Powerwall feature is still in development and is now scheduled for release in mid-2026.
This new release date gives us additional time to design and test this feature, ensuring its ability to communicate and optimize energy sharing between your vehicle and many configurations and generations of Powerwall. We are also using this time to develop additional Powershare features that will help us continue to accelerate the world’s transition to sustainable energy.”
Owners have expressed some real disappointment in Tesla’s continuous delays in releasing the feature, as it was expected to be released by late 2024, but now has been pushed back several times to mid-2026, according to the email.
Foundation Series Cybertruck buyers paid extra, expecting the feature to be rolled out with their vehicle upon pickup.
Cybertruck’s Lead Engineer, Wes Morrill, even commented on the holdup:
As a Cybertruck owner who also has Powerwall, I empathize with the disappointed comments.
To their credit, the team has delivered powershare functionality to Cybertruck customers who otherwise have no backup with development of the powershare gateway. As well as those with solar…
— Wes (@wmorrill3) December 12, 2025
He said that “it turned out to be much harder than anticipated to make powershare work seamlessly with existing Powerwalls through existing wall connectors. Two grid-forming devices need to negotiate who will form and who will follow, depending on the state of charge of each, and they need to do this without a network and through multiple generations of hardware, and test and validate this process through rigorous certifications to ensure grid safety.”
It’s nice to see the transparency, but it is justified for some Cybertruck owners to feel like they’ve been bait-and-switched.
Tesla hints at Starlink integration with recent patent
Tesla supplements Holiday Update by sneaking in new Full Self-Driving version
