Geely's Megawatt Battery, Sodium Ion Startups and the EV Battery Week in Review

The claim landed alongside a warranty extension, from eight years or 150,000 kilometres to eight years or 200,000 km, and a demo in which a Lynk & Co 10 went from 10 to 97 percent charge in 8 minutes and 40 seconds.

Battery makers do not usually put those two numbers in the same sentence. Fast charging is where cells go to die slowly, and Geely knows it. Jerry Gan, chief executive of Geely Auto Group, did not pretend otherwise. "We do not advocate fast-charging technologies at the expense of lifespan," Gan said at the Ningbo event, per InsideEVs. "If a battery frequently fast-charged is not maintained or repaired, its lifespan suffers irreversible decline."

Why megawatt charging ages cells

Geely's own engineers split the damage into two buckets: lithium plating and heat. Megawatt charging accounted for 60 percent of the heat generated inside the battery, mostly from current pushed through the cells' internal paths, the company said. About 35 percent came from electrochemical reactions and the rest from what Geely called entropic heat, the kind produced by electrode reactions. Lithium plating is the other failure mode. When ions flood the anode faster than they can be absorbed, they pile up on its surface and grow into dendrites, tiny spikes that can short a cell and kill it permanently.

Ren Xiangfei, Geely's chief engineering scientist, said the fix involved changes to the cell, the raw materials, the manufacturing process and a new AI-powered charger management system that keeps the pack inside its thermal limits.

"In an ideal world, the ions settle into the graphite evenly and smoothly," Xiangfei said, according to InsideEVs.

The physical changes are the interesting part. Geely's new cells come in two lengths, 395 mm and 370 mm, both shorter than the company's previous 580 mm cell and far shorter than the roughly 960 mm format Geely says is common in the industry. A shorter cell means a shorter migration path for ions, which lowers internal resistance and heat. Geely also widened the ion pathways in the cathode using "high entropy elements," which Xiangfei compared to turning a single lane into a multi-lane highway, and restructured the graphite anode in a way he likened to building a flyover.

For context, the fastest-charging EVs sold in the US peak around 400 kilowatts, including the Lucid Gravity and the Porsche Cayenne Electric. The upcoming Mercedes-AMG GT will peak at 600 kW. Most mass-market models in the US still average about 30 minutes for a 10 to 80 percent charge.

Meanwhile, the US bets on sodium

Geely's chemistry is still lithium. A separate push in the US is trying to move away from it entirely. San Diego-based Unigrid sells a nine kilowatt-hour home battery built on sodium ion cells. Chief executive Darren Tan told the BBC the company has shipped its first 100 units and expects to ship 1,000 before the end of the year. Inquiries are coming from Spain, France, Germany and the Netherlands, as European homeowners look for cheaper ways to run air conditioning through heatwaves.

Sodium ion has obvious appeal: potentially cheaper than lithium ion, less prone to fire and functional down to minus 40C. But there is a catch in Unigrid's design. Its cathode contains chromium-3, and under certain conditions that can convert to chromium-6, a toxic and carcinogenic material. Prof Dame Clare Grey of the University of Cambridge, co-founder of battery firm Nyobolt, told the BBC that if a company is going to sell safety, "then don't start putting elements in that are going to raise red flags."

Ivana Hasa at the University of Warwick, who has no connection to Unigrid, agreed the conversion is possible at very high states of charge. She said voltage control inside the battery can mitigate it, and described the safety tests reported on the cell chemistry as very promising. Tan called the toxicity concerns "overblown" and said third-party tests have not produced chromium-6, even under deliberate overcharging. The economics are still unsettled too: LFP cells traded at $81 per kilowatt-hour last December, while Unigrid's sodium ion pack prices at roughly $100 per kWh, according to the BBC.

The bigger picture

None of this happens in a vacuum. BloombergNEF reported on 30 September that global sales of medium- and heavy-duty electric trucks hit a record 158,000 units in the first half of 2026, up 75 percent year on year, with more than nine in ten sold in China. That is a lot of battery demand arriving at once, and it explains why charging speed and cell longevity have become the two numbers every manufacturer wants to argue about. What Geely is really selling is confidence, expressed as a warranty. What Unigrid is selling is a different chemistry with a materials question attached. Both claims will be tested by cells that have been on the road for years, not by demos.