Startup Attains Extreme-Fast EV Charging Without Cell Degradation

November 11, 2023 by Shannon Cuthrell

Cycle tests yield a significant milestone for StoreDot’s extreme fast-charging electric vehicle battery cells.

Israel-based startup StoreDot claimed a major technical win for its extreme fast-charging (XFC)-optimized cell technology for use in electric vehicle (EV) batteries. Compared to typical slow charging, the company’s tests found that its silicon-dominant 100in5 battery cells showed no additional degradation in 1,000 consecutive XFC cycles. 


StoreDot’s battery cells.

StoreDot’s battery cells. Image used courtesy of StoreDot


According to StoreDot, the full cycle tests emulated real-world charging conditions. XFC was used from 10% to 80% of the charge in 10 minutes, while slow charging was performed on the remaining cycle from 0-10% and 80-100%. The cells were also tested with slow charging cycles up to 100%, which returned a comparable cycle life performance. The cells didn’t degrade as each cycle applied XFC for most of the charge—similar to ones slow-charged from 0-100% using Level 1 or Level 2 charging equipment

As the name implies, the 100in5 cells are designed to deliver at least 100 miles of range in five minutes of charging. While the charging duration is comparable to refueling a traditional internal combustion engine car, drivers typically get 200 to 400 miles of range on a full gas tank. 

Slow charging times and range anxiety are two key sticking points for prospective EV buyers. XFC addresses both concerns, replacing at least 80% of an EV’s battery capacity in under 15 minutes and replenishing the range at 20 miles per minute of charging. XFC is still a relatively nascent market, though recent advancements in lithium-ion battery research are bringing the technology closer to commercialization. 

The quickest EV refueling option on the market is direct current fast-charging (DCFC), with a typical power output of 50 to 350 kW. According to the U.S. Department of Transportation, DCFC can charge a battery EV (BEV) to 80% in 20 minutes to an hour and unlock 180 to 240 miles of range per hour of charging. Level 1 charging equipment, on the other hand, takes 40 to 50 hours to juice a BEV from empty, offering only two to five miles of range per hourly charging session. Level 2 takes four to ten hours at ten to 20 miles of range per hour of charging.

StoreDot claims 100in5 is the only cell chemistry to support full DCFC, with 350 kW charging for 75 kWh packs. 


Video used courtesy of StoreDot


StoreDot’s Silicon-Dominant Battery Chemistry

Several factors differentiate StoreDot’s product from conventional lithium-ion batteries. StoreDot consists of an anode with 40% silicon, a nickel-rich layered oxide cathode, a highly porous ceramic-coated separator, and a stable solid electrolyte interphase layer. This battery chemistry reduces charging-induced degradation by controlling silicon’s characteristic swelling and expansion during charging and discharging. 


StoreDot’s EV battery technology.

StoreDot’s EV battery technology. Image used courtesy of StoreDot


Lithium-ion batteries equipped with silicon anodes offer a good balance of performance and weight. They provide higher electrochemical performance than anodes using graphite electrodes without the same limitations as lithium-metal electrodes. High energy density is another benefit. In silicon anodes, a single silicon atom can bind up to four lithium atoms, while a standard graphite anode requires six carbon atoms to hold one lithium atom. 

StoreDot’s battery chemistry replaces the conventional lithium-ion graphite anode with active-material nanoparticles to speed up ion diffusion. The nano-sized silicon is synthesized with small-molecule organic components, yielding a highly potent active material capable of withstanding silicon’s volume expansion. 

StoreDot’s semi-solid-state battery architecture maximizes rate capability with electrode-specific hybrid electrolytes, allowing a low-resistance flow of ions between electrodes. This hybrid-solid approach is part of the company’s near-term roadmap, but it plans to transition to a pure solid-to-solid interface cell in the next ten years. 


StoreDot’s hybrid semi-solid-state battery architecture compared to a conventional solid-state design.

StoreDot’s hybrid semi-solid-state battery architecture compared to a conventional solid-state design. Image used courtesy of StoreDot


Nearing Production

StoreDot has partnered with several leading EV original equipment manufacturers (OEMs), such as VinFast, Ola Electric, Daimler, Polestar, and Volvo Cars, as well as electronics manufacturers like Samsung and TDK. Its pouch cell pilot line and samples are based on a form factor of 300x100 mm, flexible for different customer dimensions. If the OEM requires, StoreDot can scale up to prismatic cell production. 

StoreDot expects to launch mass production for its 100in5 silicon-anode 300 Wh/kg cells next year. In 2026, it will scale to 340 Wh/kg cells, offering 100 miles of EV range in four minutes of charging. In 2028, it will transition to semi-solid 400 Wh/kg cells, enabling three-minute charging. 

Earlier this year, over a dozen OEMs from the U.S., Asia, and Europe completed a six-month evaluation of StoreDot’s silicon-based A-samples. When replicating the results over 1,000 consecutive XFC cycles, the partners achieved an energy density of more than 300 Wh/kg at a charging rate surpassing 4C. Some OEMs are now moving to phase two of testing, which involves integrating StoreDot’s B-samples with their unique form factor requirements. 

The samples will be rolled out on standard production lines with a manufacturing partner. 


StoreDot’s production process.

StoreDot’s production process. Image used courtesy of StoreDot (Page 2)


StoreDot operates existing lithium-ion manufacturing facilities for rapid production, avoiding an overhaul to accommodate its technology. Cell design, electrochemistry formulation, engineering, system integration, testing, and scaling up to sample production are all done in-house with a full-scale pilot line for faster scalability. 

The company also boasts that its AI-enabled battery optimization speeds up research and development (R&D) turnaround. StoreDot’s engineers use a Kaplan-Meier AI algorithm and other advanced analysis tools to calculate the survivability of each cell and pinpoint strategies to improve battery life. Without automation, this R&D process typically takes months or even years as researchers collect data over the cell’s entire lifecycle.