CATL's 20 Ah Solid-State Cell Is the Same Milestone It Reported in November 2024, With 500 Wh/kg Still a Target

CATL told investors on October 27 that its sulfide all-solid-state battery has reached 20 Ah sample trial production, with a target energy density of about 500 Wh/kg and small-batch production in 2027. That is the status CnEVPost reported on November 6, 2024, almost two years earlier, citing LatePost: "CATL has recently entered the trial production stage of 20 Ah samples."

The cell size, the sulfide route and the 2027 date have not moved. What has changed is what CATL has not said: no measured energy density, no cycle count, no charge rate for the 20 Ah cell.

What CATL said on October 27

The reply was posted on the Shenzhen Stock Exchange's interactive platform in answer to a question about CATL's Hefei sulfide solid-state pilot base. Gasgoo's report says CATL called its technology "industry-leading", has built a 10 Ah-level verification platform, and has moved to 20 Ah sample prototyping aiming at roughly 500 Wh/kg. Mass production is expected around 2030.

Gasgoo also gives the scale of the effort: R&D spending of 22.147 billion yuan in 2025, up 19.02% on the year, and a solid-state team of more than 1,000 people. Chairman Zeng Yuqun said at the Summer Davos Forum in June that all-solid-state batteries sit at level 4 on a 1-to-9 scale, according to Gasgoo's paraphrase. Electrek's write-up of the same reply gives the same level-4 figure.

The CnEVPost report from 2024 cited the same scale: CATL rated its maturity at 4 in April 2024 and aimed for 7 to 8 by 2027. Two and a half years on, the chairman's June 2026 answer is still 4.

How big a 20 Ah cell is

The number that matters here is not 500 Wh/kg but 20 Ah. CATL's lithium iron phosphate cell listed on Wikimedia Commons is rated 302 Ah and weighs up to 5.51 kg. A 20 Ah cell holds about one fifteenth of that capacity. At an assumed nominal 3.7 V (our assumption, not a CATL figure), 20 Ah is roughly 74 Wh, which is a laboratory-scale sample, not a vehicle cell.

The 2024 report also recorded that charging speed and cycle life "have yet to meet expectations", and that safety and performance challenges remained at the 20 Ah stage. Electrek's October piece names the remaining hurdle as keeping solid components in stable contact, and says it found no measured figure for current cells.

Where the rivals say they are

Electrek lists the competing timelines. They bunch around 2027, with mass production at the end of the decade.

Maker	Stated plan
CATL	Small-scale production 2027, mass production about 2030
Toyota	First all-solid-state EV in 2027 or 2028, limited volume
Samsung SDI	Mass production of SolidStack in second half of 2027
BYD	First solid-state vehicle in 2027; limited sulfide batches, mass production by 2030

Toyota claims a prototype range of 745 miles (1,200 km) and a charge in under 10 minutes; those are Toyota's own claims, not independently tested. CATL held 39.9% of the global EV battery market in the first half of 2026, per SNE Research as cited by Electrek, so it is the incumbent whose chemistry choices decide how fast any of this reaches cars.

A target is not a measurement

The distinction recurs across the hardware desk's beat. Tesla said on October 21 that Optimus production had begun at Fremont, and its update gave no production volumes, so the 20,000-a-week figure remains a target set against car deliveries. The same discipline applies here: 500 Wh/kg is where CATL aims, and the sources fetched give no measured figure for the 20 Ah cell.

It also matters for how the milestone is priced. Capital flowing to physical technology is large, as Crunchbase's robotics tallies showed, and investors asking CATL about solid-state progress on an exchange platform are asking a question about a cell that has been at the same size since 2024. A reply that says "industry-leading" and "2027" answers the schedule question and leaves the performance question open.

Density is one axis of three. Cost per kilowatt-hour and cycle life are the others, and nothing in the October reply addresses either. Electrek itself notes that lithium iron phosphate and sodium-ion cells will keep supplying lower-cost options for different needs, and cites reports that BYD's second-generation Blade cells offer more than 1,000 km of CLTC range without a solid electrolyte. A solid-state cell has to beat those on price, not only on watt-hours per kilogram.

What would change my read

The milestone to watch is a published cell-level result: Wh/kg measured rather than targeted, cycles to 80% capacity, and a charge time. A 500 Wh/kg figure for a 20 Ah sample would be meaningful only alongside those three. Until CATL or an independent lab supplies them, the 2027 date is a plan that has stayed the same for two and a half years while the maturity rating has not advanced.

The other variable is cell format. A move from 20 Ah to the several-hundred-amp-hour cells vehicles use is the step that turns a lab result into a supply chain, and none of the sources fetched report a date for it.