Lithium News

Tesla has announced that it has produced its 100 millionth 4680 battery cell across all its factories. The update came just over three months after the company announced that it had produced a total of 50 million 4680 cells.

The milestone was posted on Tesla’s official social media account on X. Tesla included an image of its 100 millionth 4680 battery being held by an Optimus Gen 2 humanoid robot in its post.

Industry watchers who have closely watched the development of Tesla’s 4680 program were quite impressed with the electric vehicle maker’s recent milestone. Tesla, after all, just announced on June 5 that it had produced its 50 millionth 4680 cell at Giga Texas.

Considering the 101 days that have elapsed since the June announcement, Tesla appears to have produced, at least on average, about 495,000 4680 cells per day. Each Cybertruck is equipped with 1,344 4680 cells, so such an average output would translate to a production capacity of about 368 Cybertrucks a day, or 2,578 per week.

This also suggests that based on the output of the 4680 battery cells, Tesla could produce 33,514 Cybertrucks per quarter, or about 134,280 units of the all-electric pickup truck per year, as estimated by Tesla battery enthusiast The Limiting Factor in a post on X.

Recent aerial footage taken of the Giga Texas complex reveals that the electric vehicle maker is hard at work ramping up the production of the Cybertruck. Despite this, recent estimates hint that Tesla is still just closing in on producing 2,000 Cybertrucks per week.

This may then suggest that for now, at least, the supply of 4680 cells is no longer the bottleneck for the Cybertruck’s production. Of course, Tesla may also be stockpiling some 4680 cells in preparation for the Cybertruck’s increase in production once the Foundation Series formally ends.

The progress of Tesla’s 4680 battery cell program has been remarkable this year. Announced in Tesla’s 2020 Battery Day event, the 4680 cell program saw notable delays, to the point where company critics were claiming that Elon Musk might give up on the whole program. Earlier this year, however, a report from China emerged stating that Tesla is finally planning on mass producing the “complete” version of the 4680 cell—which includes a dry positive and negative electrode—by the end of this year.

Accurate prediction of lithium battery lifespan is crucial for the proper functioning of electrical equipment. However, predicting battery lifespan accurately is challenging due to the nonlinearity of capacity degradation and the uncertainty of operating conditions.

Recently, Prof. Chen Zhongwei and Assoc. Prof. Mao Zhiyu from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences, in collaboration with Prof. Feng Jiangtao from Xi’an Jiaotong University, designed a novel deep learning model, the dual stream-vision transformer with the efficient self-attention mechanism (DS-ViT-ESA), to predict the current cycle life (CCL) and remaining useful life (RUL) of the target battery. The study was published in IEEE Transactions on Transportation Electrification.

The researchers developed the deep learning model using a small amount of charging cycle data. This model employed a vision transformer structure with a dual-stream framework and an efficient self-attention mechanism to capture and integrate hidden features across multiple time scales.

The model was able to accurately predict the battery’s CCL and RUL. With just 15 charging cycle data points, it achieved RUL and CLL prediction errors of only 5.40% and 4.64%, respectively. Moreover, the model maintained low prediction errors even when tested on charging strategies not included in the training dataset, demonstrating its zero-shot generalization capability.

This battery lifespan prediction model was also a crucial component of the first-generation Battery Digital Brain, called PBSRD Digit. The system integrated with this algorithm has significantly improved accuracy. Currently, the Battery Digital Brain system serves as the core energy management system for large-scale commercial storage and electric vehicles, with the capability to be deployed on both cloud servers and client-side embedded devices.

“The battery lifespan prediction model effectively balances prediction accuracy with computational cost, thereby increasing the application value of the Battery Digital Brain for lifespan estimation,” said Prof. Chen. “We plan to further optimize the model using techniques such as model distillation and pruning, aiming to enhance robustness and resource utilization of the system.”

Most rechargeable batteries that power portable devices, such as toys, handheld vacuums and e-bikes, use lithium-ion technology. But these batteries can have short lifetimes and may catch fire when damaged.

To address stability and safety issues, researchers reporting in ACS Energy Letters have designed a lithium-sulfur (Li-S) battery that features an improved iron sulfide cathode. One prototype remains highly stable over 300 charge-discharge cycles, and another provides power even after being folded or cut.

Sulfur has been suggested as a material for lithium-ion batteries because of its low cost and potential to hold more energy than lithium-metal oxides and other materials used in traditional ion-based versions. To make Li-S batteries stable at high temperatures, researchers have previously proposed using a carbonate-based electrolyte to separate the two electrodes (an iron sulfide cathode and a lithium metal-containing anode).

However, as the sulfide in the cathode dissolves into the electrolyte, it forms an impenetrable precipitate, causing the cell to quickly lose capacity. Liping Wang and colleagues wondered if they could add a layer between the cathode and electrolyte to reduce this corrosion without reducing functionality and rechargeability.

The team coated iron sulfide cathodes in different polymers and found in initial electrochemical performance tests that polyacrylic acid (PAA) performed best, retaining the electrode’s discharge capacity after 300 charge-discharge cycles.

Next, the researchers incorporated a PAA-coated iron sulfide cathode into a prototype battery design, which also included a carbonate-based electrolyte, a lithium metal foil as an ion source, and a graphite-based anode. They produced and then tested both pouch cell and coin cell battery prototypes.

After more than 100 charge-discharge cycles, Wang and colleagues observed no substantial capacity decay in the pouch cell. Additional experiments showed that the pouch cell still worked after being folded and cut in half. The coin cell retained 72% of its capacity after 300 charge-discharge cycles.

They next applied the polymer coating to cathodes made from other metals, creating lithium-molybdenum and lithium-vanadium batteries. These cells also had stable capacity over 300 charge-discharge cycles. Overall, the results indicate that coated cathodes could produce not only safer Li-S batteries with long lifespans, but also efficient batteries with other metal sulfides, according to Wang’s team.

Replacing gadgets like smartphones or laptops just because the battery stops holding charge can be a real headache. But new research outlines a way to give common lithium-ion batteries a much longer lifespan — starting with their very first charge cycle.

Charging Li-ion batteries — which power most personal electronics and electric vehicles (EVs) — at high temperatures or currents before they hit the shelves could extend their average lifespans by 50%, researchers said in a new study published Aug. 29 in the journal Joule.

The results “demonstrate a generalizable approach for understanding and optimizing this crucial step in battery manufacturing,” said study coauthor Steven Torrisi, a senior research scientist at the Toyota Research Institute in California, in a statement.

A typical Li-ion battery has a positive and a negative electrode in an electrolyte solution containing lithium ions. When you charge the battery, lithium ions move into the negative electrode. Then, when you use the battery and expend its charge, the lithium ions move out of the negative electrode and into the positive one. The back-and-forth flow of ions facilitates the electric current that powers a device.

A brand-new Li-ion battery is completely discharged — the positive electrode is full of lithium, and the negative electrode has plenty of space for lithium ions to flow into. But on the first charge, some of the lithium in the battery gets stuck on the surface of the negative electrode. The trapped lithium, along with other components of the electrolyte solution, becomes part of a layer called the solid electrolyte interphase (SEI). This SEI encases the negative electrode, protecting it from side reactions that cause further loss of lithium and so shorten the battery’s lifespan.

Usually, manufacturers first charge the battery slowly to build up a stable SEI. But that isn’t always the most cost-effective approach — and recent studies show that charging the battery quickly doesn’t necessarily have a negative impact on the battery’s life. What’s more, several other parameters can impact the SEI, so it’s not easy to optimize the first charge for the best battery performance.

In the new study, researchers used machine learning to pick out the parameters that have the strongest effect on the SEI. Two factors — the current and temperature during the first charge — grabbed their attention.

Charging the battery over about 20 minutes, instead of the usual 10 hours or so, extended the battery’s overall lifetime by about 50%. More lithium gets stuck in the SEI on the first charge, but that limits the possibility of future side reactions that can shorten the battery’s life on subsequent cycles.

Raising the temperature from room temperature to 131 degrees Fahrenheit (55 degrees Celsius) had a similar effect, improving the battery’s lifespan by an average of 57%. That improvement likely comes from changes in the SEI composition that make it more robust, the researchers said. However, the techniques didn’t synergize: charging the cell both quickly and at high temperatures didn’t improve battery performance.

“We didn’t just want to identify the best recipe for making a good battery; we wanted to understand how and why it works,” said study coauthor Will Chueh, a materials scientist at Stanford University, in the statement. “This understanding is crucial for finding the best balance between battery performance and manufacturing efficiency.”

The new strategy could make batteries cheaper too, Chueh said. “This is an excellent example of how [the Stanford Linear Accelerator Center] is doing manufacturing science to make critical technologies for the energy transition more affordable,” he noted. “We’re solving a real challenge that industry is facing.”

Mercedes is getting new all-solid-state EV batteries for its next-gen models. Developed with Factorial, its new all-solid-state battery “breakthrough” can extend EV range by up to 80%.

Mercedes is getting new all-solid-state EV batteries
Factorial is “at the cutting edge” of solid-state EV battery tech. The US-based company claims its tech will extend EV range, increase safety, and reduce costs compared to what’s on the market today.

Mercedes was among several automakers, including Hyundai and Stellantis, that invested in Factorial’s $200 million fundraise in 2022.

The company has been advancing its proprietary solid-state FEST (Factorial Electrolyte System Technology) platform for years. Its solid-state battery cells based on the FEST platform were delivered to Mercedes earlier this summer.

On Tuesday, Factorial introduced its latest breakthrough, Solstice. The new all-solid-state EV battery was developed with Mercedes to power its next-gen models.

Factorial said its sulfide-based system addresses concerns over flammable liquid electrolyte designs. It will also maintain stability when operating at temperatures over 194°F (90°C).

The safer design can reduce the need for heavy cooling systems within the battery pack, which can drive even lower prices.

With a “breakthrough energy density” of 450 Wh/kg, Factorial claims the new tech can extend EV range by up to 80%. It will also drastically reduce the weight of EVs for even higher efficiency.

Factorial aims to unlock over 600 miles of driving range for future electric models with 40% weight savings (compared to traditional Li-ion batteries). The company says its tech is also 33% smaller.

Solstice will complement Factorial’s FEST platform for safer and more efficient electric vehicles. The new all-solid-state EV batteries are expected to launch by the end of the decade.

According to chief tech officer Markus Shafer, the new tech is a “cornerstone of Mercedes-Benz’s strategy and commitment” to leading EV battery development. Shafer added that Solstice will help Mercedes “set new standards in range, cost, and performance.”

The new tech comes a day after after Toyota announced its plans to develop and produce all-solid-state EV batteries have been certified in Japan.

Toyota is among several leading Japanese companies, including Nissan and Panasonic, aiming to boost domestic production. Japan seeks to secure a stable domestic supply chain to reduce reliance on China and South Korea, which currently dominate the global battery market.

Automakers are betting on solid-state batteries for longer-range, more efficient electric vehicles. However, significant challenges, including poor performance in extreme weather, have proven to be more complex than expected.