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Tesla “Battery Day” event date is looking like April 2020, says Elon Musk
Tesla CEO Elon Musk said the company is preparing to host a Battery Day for shareholders sometime after the first quarter, possibly in April. The announcement came during the earnings call following Tesla’s release of its Q4 2019 Update Letter.
Responding to a question from a participating investor about where Tesla stands in growing its battery capacity, Musk said that the company has already demonstrated massive improvement in growing the capacity of the cells, modules, and batteries it uses for its all-electric vehicles.
The CEO attributed part of the improvements to Tesla’s relationships with various battery partners, such as Panasonic, which is Tesla’s in-house supplier of lithium-ion batteries at Giga Nevada. Tesla also teamed up with other partners such as LG and CATL to produce battery packs for its cars produced in China. Aside from that, Musk declined to provide additional details on future plans for improving its battery technology, leaving investors to look forward to the upcoming Battery Day event later this year.
“We have a lot more to talk about this in detail in Battery Day probably April. We have a very compelling strategy. I mean, we are super deep in cell. Super deep. Cell through battery,” he said.
Tesla’s efforts to upgrade its batteries include the acquisition of California-based energy storage firm Maxwell Technologies, which was completed in May last year. Tesla’s interest in Maxwell primarily lies in the latter’s innovations in ultracapacitors and dry electrode technologies, which could potentially improve the company’s batteries.
Prior to the acquisition, Tesla also submitted a patent for an idea to use electrolyte additives to improve the performance and lengthen the lifespan of lithium-ion cells. The patent, titled “Dioxazolones and Nitrile Sulfites as Electrolyte Additives for Lithium-ion Batteries,” provided details on how Tesla can significantly increase the lifespan and performance of its batteries by adding electrolyte additives such as lithium salt. Tesla also submitted another patent for using cold plates and heat pipes to reduce heat generated by the battery, thereby increasing the longevity of its energy storage systems.
The latest developments appear to be moving Tesla toward the completion of a 1-million mile battery. In April last year, Musk said that Tesla owners will soon be able to drive their cars for up to 1 million miles over the lifespan of their vehicles. This is equivalent to 20 years if the cells are used for energy storage systems. Tesla lead researcher Jeff Dahn and a team from the Dalhousie University physics and atmospheric science department have also developed pouch cells that can last 1 million miles or 20 years in a grid storage system.
Tesla’s huge lead in the electric vehicle market is due in part to its constant efforts to improve its battery technology. In fact, its batteries have improved so much over the years that the Model S is nearing a range of 400 miles. The published range for the luxury sedan is 373 miles, but Musk said during the earnings call that the actual range is somewhere in the 380s.
“S and X actually have more range than we are currently stating on the website. We just haven’t gotten around to updating the EPA […] number, but the actual range of the Model S and X are above what the website says they are,” he said. “Somewhere in the 380s, something like that.”
He also added that the 18650 lithium-ion cells that power the Model S and X have largely improved over the years, adding that further developments could raise the range of the Model S to 400 miles.
“I think we’re pretty happy with the energy content of the cell and the improvements in the efficiency of the vehicle,” he said. “We’re rapidly approaching a 400-mile range for the Model S, for example.”
Battery Day is expected to be similar to Autonomy Day, which was held in April last year. The event, which was attended by investors and also available via livestream, was a full three-hour technical discussion of Tesla’s work on autonomous driving technology and how the company plans to achieve its goal of delivering fully self-driving cars.
Elon Musk has acknowledged that early discussions with Taiwan Semiconductor Manufacturing Company (TSMC) could bring the company into his ambitious Terafab semiconductor project, signaling a possible partnership with the world’s leading contract chipmaker.
Musk confirmed that early talks are underway, but as of right now, they are “just discussions.” There is no confirmation of a deal nor dismissal of the possibility of one, leaving open the prospect of one of the largest advanced-chip collaborations under discussion in the U.S.
@wholemars Just discussions, but something may come of it
— Elon Musk (@elonmusk) October 3, 2026
The report that speculated on potential discussions between Terafab and TSMC comes from Tim Culpan, who outlined a few ways the collaboration could operate. One is TSMC using the project as an “anchor customer” for future facilities in Texas, potentially contributing process expertise, operational know-how, or capacity while Terafab provides capital, long-term purchase commitments, or both.
Tesla and SpaceX jointly developed the Terafab project, with Intel already participating on the tech side. Elon Musk announced the project in March, and it intends to produce more than one terawatt of AI compute capacity annually once fully built.
Company statements place the first phase at approximately $16.8 billion in cost, with later filings pointing to a total that could reach well into the tens of billions across multiple stages.
Intel joined the effort in April 2026 and is expected to supply its 14A manufacturing process for the full-scale plant.
Musk has said existing suppliers, including Samsung and TSMC, remain important for near-term needs; Tesla already has production arrangements with Samsung for AI5 and AI6 chips, but that future demand from Optimus robots, Cybercab vehicles, and planned space-based data centers will eventually exceed what the global industry can currently deliver.
Terafab is positioned as the long-term answer to that projected shortfall, and Tesla did something similar during COVID to avoid a chip shortage. This is just a much larger-scale solution.
If the partnership were to materialize, it would add TSMC’s industry-leading strategies to a project that already combines Tesla’s and SpaceX’s capital and offtake with Intel’s process technology. For now, the only public confirmation is Musk’s brief acknowledgement that conversations are occurring.
Tesla’s early strategy for charging units operating within its Robotaxi fleet reveals that the company surely has not lost any of that scrappy DNA that took it from an unlikely success story to the most valuable carmaker in the world.
An observer at a Tesla Supercharger in Austin spotted ten total Robotaxi vehicles arrive: one Cybercab and nine Model Y units. A Tesla employee was waiting at the lot and allowed each unit to park itself; every car that arrived had nobody in it.
Tesla wins FCC approval for wireless Cybercab charging system
The Tesla employee would walk around and plug each car in, adjusting the parking if needed:
So look at what I found. This is how Tesla charges unsupervised robotaxis at a public supercharger. Here is a driverless Cybercab showing up with no one in it. There are 9 other Model Ys that showed up too. A Tesla employee is walking around and plugging each of them in. She also moves the cars if they are not positioned well enough to charge. I love this process. One person charges multiple robotaxis at once
— Abhimanyu Yadav (@WorldlyReviewer) October 3, 2026
It’s a very interesting strategy, but extremely understandable at this early point in the Robotaxi program. It’s only been out for about 15 months, and Cybercab just entered the fleet in early September.
On top of that, Tesla is still working tirelessly on its wireless charging apparatus, and a new patent was just published regarding that product last week.
However, this is just another example of how Tesla still has plenty of that scrappy DNA leftover from the “production hell” days, when CEO Elon Musk slept on the floor of the factory, employees were working crazy hours, Tesla was building Sprung Structures to build cars in, and the company was tiptoeing on the brink of bankruptcy.
@Teslarati Sheer magnitude of the entire production system is hard to appreciate. Almost every element of production is >75% automated. Only wire harnesses & general assembly, which are <10% of production costs, are primarily manual.
— Elon Musk (@elonmusk) October 12, 2020
For now, Tesla is utilizing a simple system for recharging its ride-hailing vehicles, and that is a Tesla employee doing it manually until another solution presents itself. Sure, it’s not the most high-tech thing, and it certainly is not what people might have expected at this point in time, but it works, and it’s keeping the entire suite running.
Tesla is expanding its Robotaxi service hours by pushing the time back by one hour, keeping the ride-hailing service operational until 11 p.m., one hour later than previously.
CEO Elon Musk confirmed the change and offered a specific reason the expansion has been gradual: the system still needs to reliably avoid small pets that are difficult to see after dark, as they commonly blend into the color of the road, especially when they’re grey.
The latest adjustment restores only a fraction of the operating window the service once held. When paid Robotaxi rides began in Austin on June 22, 2025, vehicles ran from 6 a.m. to midnight.
In September 2025, Tesla lengthened the day to a 2 a.m. close, producing a 20-hour window that stayed in place for most of the following year. By early August of this year, the cutoff had already been pulled back; an August 26 update formalized hours of 6 a.m. to 10 p.m. across Austin and several other markets.
The October move to 11 p.m. therefore leaves the Austin day one hour shorter than the original launch schedule and three hours shorter than the 2025 peak.
Musk addressed the constraint directly after the announcement. “The main thing we’re trying to solve is making sure that we don’t run over pets when they’re hard to see at night,” he wrote. “Literally trying to avoid grey kittens on grey tarmac in the dark.”
Robotaxi operating hours moved from 10pm to 11pm.
The main thing we’re trying to solve is making sure that we don’t run over pets when they’re hard to see at night. Literally trying to avoid grey kittens on grey tarmac in the dark.
— Elon Musk (@elonmusk) October 3, 2026
The example points to a low-contrast perception problem in which a small animal can blend into the road surface under limited lighting.
Tesla’s vehicles rely on cameras and neural-network processing rather than lidar; Musk has previously argued that advanced vision software can extract useful information even in low light by analyzing photon counts, but the pet-detection case remains the stated limiter in later hours.
The modest schedule change arrives alongside faster growth in the purpose-built Cybercab fleet. Texas registration data tracked by observers showed the Austin Cybercab count rising sharply in recent weeks, reaching 169 vehicles after more than 100 were added in a short span.
Tesla has indicated that a broader shift toward 24-hour operation is tied to the upcoming FSD v15 software release expected this month on Robotaxi vehicles. Until that capability is validated for the edge cases Musk described, the company continues to add service time incrementally rather than jumping straight to overnight coverage.
The one-hour extension gives Austin riders a later option for evening trips while the underlying detection work continues.
Elon Musk teases TSMC as potential Terafab partner
Tesla reveals early Robotaxi charging strategy, showing scrappy DNA
