Somewhere between the lithium-ion batteries that power today’s electric cars and the fully solid-state cells that laboratories keep promising for “a few years from now,” a middle child has quietly entered service. In early 2026, Chinese battery makers began shipping semi-solid-state packs rated at roughly 350 watt-hours per kilogram to two categories of vehicle that punish heavy batteries the most: light commercial delivery trucks and electric vertical takeoff and landing (eVTOL) aircraft. The cells swap most of the flammable liquid electrolyte in a conventional lithium-ion pack for a gel or polymer layer, cutting fire risk during thermal runaway while keeping enough liquid to move lithium ions at usable speeds.
What separates this rollout from earlier lab demonstrations is a regulatory gate that every pack must now clear. China’s updated mandatory traction-battery safety standard, GB 38031-2025, took effect this year, replacing the 2020 edition with tighter thermal-runaway thresholds. Any cell sold for use in a Chinese-market vehicle must survive nail penetration, overcharge, and external short-circuit abuse tests without fire or explosion. For fleet operators, insurers, and foreign automakers watching from the sidelines, that standard offers the first enforceable benchmark against which to judge semi-solid-state marketing claims.
Who is building what
Several Chinese manufacturers have publicly tied their semi-solid-state cells to vehicle deployments. WeLion New Energy, a spinoff from the Chinese Academy of Sciences, has announced pack shipments for light trucks and has discussed supplying cells to eVTOL developers. Ganfeng Lithium, better known as a lithium mining giant, has pushed its own semi-solid-state line into commercial samples. CATL, the world’s largest battery maker, unveiled what it calls a “Condensed Battery” with a semi-solid architecture and has said the technology targets aviation-grade energy density. On the aircraft side, companies like EHang and AutoFlight have been exploring higher-density cells to extend flight range, a constraint that conventional liquid-electrolyte packs struggle to solve because every extra kilogram of battery weight eats directly into payload and airtime.
The 350 Wh/kg figure circulating in manufacturer announcements refers to cell-level energy density. That distinction matters. Once you add the casing, cooling hardware, wiring harness, and battery management electronics needed to build a complete pack, energy density typically drops by 20 to 40 percent. A 350 Wh/kg cell becomes roughly 210 to 280 Wh/kg at the pack level. That is still a meaningful jump over today’s best conventional NMC packs, which sit around 180 to 200 Wh/kg at the pack level in most production vehicles, but it is not the transformative leap that headline numbers sometimes imply.
The regulatory backbone
GB 38031-2025 was published by China’s State Administration for Market Regulation and the Standardization Administration, the two agencies that jointly govern product safety rules. Its registry entry on the national standards portal confirms the standard’s scope, issuing bodies, and mandatory status. Because the standard carries legal force for every traction battery sold in China, it functions as a market gatekeeper: manufacturers that cannot certify against it lose access to the world’s largest EV market, which sold more than 10 million new energy vehicles in 2024 alone.
That gatekeeper role has global ripple effects. Many Chinese cell makers produce for both domestic and export customers on the same lines. A cell designed to pass GB 38031-2025 abuse tests will likely meet or exceed the UN ECE R100 requirements used in Europe and the safety provisions in U.S. Federal Motor Vehicle Safety Standards, though direct equivalence cannot be assumed without separate certification. The practical result is that China’s domestic standard increasingly shapes battery design decisions far beyond its borders.
The State Administration for Market Regulation, whose main site at samr.gov.cn aggregates product-safety notices, has a track record of using recalls and spot checks to enforce compliance. That enforcement history gives the standard teeth: manufacturers know that shipping a non-compliant pack risks costly interventions once vehicles reach the road.
What has not been proven yet
Passing a lab abuse test is not the same as surviving five years of daily delivery routes. Several critical questions remain open, and buyers should weigh them carefully.
Independent verification is missing. No publicly available test report from China’s market regulator or its affiliated laboratories details the exact cells installed in the trucks or eVTOL prototypes, the measured energy density at the pack level, or cycle-life data at that density. The 350 Wh/kg figure comes from manufacturer press materials, not from a third-party teardown or a peer-reviewed study.
Type-approval records are incomplete. Direct regulatory filings confirming which specific vehicle models received certification under the 2025 standard were not posted on the government portals reviewed for this article as of late May 2026. That gap makes it hard to verify whether the trucks and aircraft currently operating with semi-solid-state packs were certified under the new standard or under transitional provisions tied to the 2020 edition.
Cycle life at high density is uncharted. Solid and semi-solid electrolytes can develop interface resistance over repeated charge-discharge cycles, gradually reducing usable capacity. No manufacturer has released long-duration aging data for cells at the claimed density, and no independent lab has published results confirming how many full cycles these packs sustain before dropping below 80 percent of original capacity. For a delivery truck running 300 days a year, that number determines whether the battery outlasts a lease term or becomes a write-off.
Cold-weather fast charging is a question mark. Semi-solid electrolytes conduct lithium ions more slowly than liquid ones at low temperatures, which can throttle charging speed. Whether the deployed packs can accept the rapid charging rates that fleet logistics demand, particularly in northern Chinese provinces where winter temperatures regularly drop below minus 20 degrees Celsius, has not been addressed in any public filing.
Real-world crash and fire data does not exist yet. Abuse tests in GB 38031-2025 simulate specific failure modes under controlled conditions, but they cannot replicate every combination of mechanical damage, manufacturing defect, and environmental stress that fleets encounter. Without incident reports or insurance loss data tied specifically to semi-solid-state packs, outside observers have limited visibility into how these batteries behave when something goes wrong outside the lab.
How this fits the global battery race
China’s semi-solid-state deployments land at a moment when every major battery-producing nation is chasing the same prize: a cell dense enough to make electric trucks and aircraft practical, safe enough to insure, and cheap enough to compete with diesel. Toyota has said it aims to begin mass production of fully solid-state cells by 2027 or 2028. Samsung SDI has demonstrated prototype solid-state cells but has not announced vehicle-level deployments. QuantumScape, the U.S. startup backed by Volkswagen, has shipped sample cells to automotive partners but has not reached volume production.
The Chinese approach sidesteps the hardest manufacturing problems of full solid-state by keeping some liquid electrolyte in the cell. That compromise sacrifices the theoretical maximum energy density and the complete elimination of flammable material, but it allows production on modified versions of existing lithium-ion equipment rather than requiring entirely new factory lines. For companies trying to get product into vehicles now rather than in 2028, the trade-off is deliberate.
Whether that pragmatism holds up depends on data that does not yet exist in the public domain. If semi-solid-state packs prove durable over hundreds of thousands of fleet kilometers and their safety record under GB 38031-2025 holds through real-world incidents, Chinese manufacturers will have established a commercial lead that fully solid-state competitors will need years to close. If cycle life disappoints or cold-weather limitations prove severe, the technology may end up as a transitional step rather than a destination.
What fleet buyers and investors should look for next
For fleet operators considering semi-solid-state packs today, the practical first step is to request the GB 38031-2025 test certificate for the specific cell model being offered and confirm that the certificate was issued by an accredited laboratory listed on the Standardization Administration website. That document, not a press release, is the evidence that the pack met the thermal-runaway, overcharge, and short-circuit thresholds spelled out in the standard. Buyers should also demand pack-level energy-density figures and warranty terms tied to cycle-life guarantees, since those details determine whether the higher upfront cost will be offset by longer service life.
Investors and policymakers should apply a similar filter. When a manufacturer claims its new semi-solid pack “meets national standards,” the relevant follow-ups are: which standard, certified by whom, and for what vehicle configuration? A pack that passes abuse tests in a small delivery van may need significant redesign before it can safely power a heavier truck or an aircraft, where thermal management constraints and redundancy requirements are fundamentally different.
The regulatory foundation here is real and enforceable. The commercial case is plausible but unproven. Separating those two layers is the clearest way to read what is happening in Chinese battery manufacturing right now, and the clearest way to avoid mistaking a promising start for a finished product.
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*This article was researched with the help of AI, with human editors creating the final content.
