Somewhere between the liquid-electrolyte lithium-ion packs that power virtually every electric car on the road today and the fully solid-state batteries that companies like Toyota keep promising for “later this decade,” there is a middle step that just cleared a critical gate. In May 2025, China’s Ministry of Industry and Information Technology (MIIT) published Batch 398 of its Road Motor Vehicle Manufacturer and Product Announcement, the official catalog that every automaker in China must pass before a single vehicle can be manufactured or sold domestically. Listed inside: MG variants equipped with semi-solid-state battery packs. No other automaker has pushed this next-generation cell chemistry through a national production-vehicle approval process, making MG, and its parent company SAIC Motor, the first to cross from prototype territory into the regulatory pipeline for mass manufacturing.
Why the MIIT filing matters more than a press release
MIIT approval is not a concept-car unveiling or an investor-day slide. It is a binding regulatory act. To appear in a batch announcement, an automaker must submit full engineering documentation, pass a technical review covering crash standards, electrical safety, and battery-management requirements, and provide traceable component data. The ministry also operates a public query system where anyone can download parameter-page PDFs for listed vehicles, including battery specifications and energy-density figures. The fact that downloadable parameter pages exist for the MG semi-solid-state variants confirms this is not a placeholder filing; the technical data has been reviewed and published.
In China’s fast-moving EV sector, the gap between MIIT listing and first customer deliveries is often a matter of months. Recent precedents, such as Xiaomi’s SU7 sedan, moved from batch listing to showroom availability within a single quarter. SAIC operates large-scale manufacturing facilities with deeply integrated supply chains, which makes a prolonged delay between approval and output unlikely, though no official start-of-production date has been announced as of June 2025.
Semi-solid-state batteries, explained briefly
The “semi-solid” label describes a cell that replaces most or all of the liquid electrolyte found in conventional lithium-ion batteries with a gel or polymer layer, while retaining some liquid components. The payoff is meaningful: higher energy density (more range per kilogram of battery), better thermal stability (the cells are harder to push into thermal runaway), and the potential for longer cycle life. Several Chinese cell makers, including WeLion New Energy and Ganfeng Lithium, have published targets in the range of 350 to 400 watt-hours per kilogram for their semi-solid-state cells, a significant jump from the roughly 250 Wh/kg that top-tier conventional NMC packs deliver today.
For drivers, the practical translation is straightforward: longer range from a smaller, lighter battery pack, and, at least in theory, improved safety margins. The technology is not the same as the fully solid-state cells that Toyota and Samsung SDI have targeted for 2027 or 2028, which aim to eliminate liquid components entirely. Semi-solid-state sits one rung below on the ambition ladder but one rung above on the readiness ladder, and MG’s MIIT listing is the strongest evidence yet that the chemistry is ready for real-world production vehicles.
What we know and what we don’t
Confirmed: MIIT has approved specific MG variants with semi-solid-state battery packs for production in China. The filing includes downloadable technical parameter pages. SAIC Motor, MG’s parent, is one of China’s largest state-backed automakers with the manufacturing infrastructure to scale production.
Not yet confirmed: The exact MG model names and trim levels carrying the new packs have not been widely detailed in English-language sources. The identity of the cell supplier has not been explicitly confirmed in the Batch 398 documents themselves, though WeLion, CATL, and Ganfeng have all disclosed semi-solid-state programs at various stages. Pricing, specific range figures, and fast-charging specifications are not disclosed in the MIIT filing and have not been independently verified.
Important nuance: NIO has offered a 150-kWh semi-solid-state battery pack (supplied by WeLion) as a rental option for select models since 2024, but that pack was an aftermarket swap available in limited numbers, not a factory-standard configuration cleared through MIIT’s production-vehicle process. MG’s distinction is that its semi-solid-state packs are integrated into the vehicle as approved for series production, a harder regulatory and engineering bar to clear.
The competitive picture
MG’s filing does not exist in a vacuum. China’s battery industry has been racing toward semi-solid and solid-state chemistries with an intensity that dwarfs efforts elsewhere. CATL unveiled what it calls a “condensed-matter” battery in 2023 with a claimed energy density above 500 Wh/kg, though that cell has not yet appeared in a production-vehicle MIIT listing. Toyota has repeatedly stated its goal of commercializing fully solid-state batteries by the late 2020s but has not announced a production vehicle. Samsung SDI has disclosed pilot-line work on solid-state cells for automotive use, with volume production targeted no earlier than 2027.
Among Chinese automakers, BYD continues to dominate with its lithium iron phosphate Blade battery, which prioritizes safety and cost over maximum energy density. BYD has not publicly disclosed a semi-solid-state program tied to a specific production vehicle. That leaves SAIC, through MG, holding the first confirmed regulatory approval for the technology in a mass-market brand.
For global markets, the question is when, not whether, semi-solid-state packs will appear outside China. MG already sells EVs in Europe, Australia, and parts of Southeast Asia. European type-approval and UN ECE battery-safety regulations would require a separate certification process, and there has been no announcement about international availability. But the MIIT filing establishes a manufacturing baseline: once SAIC is building these packs at scale for the domestic market, adapting them for export becomes an engineering and regulatory exercise rather than a fundamental technology challenge.
How to judge battery breakthroughs going forward
The MG case offers a useful filter for evaluating the steady stream of battery announcements that land in headlines every month. Press events and investor presentations are marketing. Prototype demonstrations are engineering milestones. But a national regulator listing a specific vehicle variant with a new battery chemistry in a production-approval catalog is something harder to fake or exaggerate. In China, that means checking MIIT batch announcements and looking for downloadable parameter pages. In Europe, it means watching for type-approval documents and homologation certificates. In the United States, it means tracking EPA range certifications and NHTSA safety filings.
By that standard, MG’s semi-solid-state battery has crossed the most meaningful threshold available: a government regulator has reviewed the engineering, checked the safety data, and said yes, build it. What happens next, how fast SAIC ramps production, what the cells cost at scale, and how they hold up after tens of thousands of real-world kilometers, will determine whether this is a footnote or a turning point. But the starting gun has fired, and MG pulled the trigger first.
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*This article was researched with the help of AI, with human editors creating the final content.
