BYD Files Six New Solid-State Battery Patents, Aiming for Small-Scale Production in 2027

BYD has published six new patents covering solid-state battery technology, all filed with China’s National Intellectual Property Administration between late July and early August 2026. The company is targeting small-scale production of these cells in 2027, with the first batches going into camouflaged test vehicles before anything reaches a showroom.

What the patents actually cover

The core idea across all six filings is a dual-electrolyte cathode. Solid-state batteries need to move ions around without a liquid electrolyte, and two of the main solid electrolyte types, halide and sulfide, are each good at different things. Halide electrolytes are chemically stable, sulfide electrolytes move lithium ions much faster. Put them directly next to each other, though, and they react badly, degrading the cell before it’s done much work at all. BYD’s patents describe an ultra-thin buffer layer sandwiched between the two, letting ions pass through while keeping the halide and sulfide from touching directly.

What did BYD patent for solid-state batteries?
BYD filed six patents covering a dual-electrolyte cathode design that combines halide and sulfide solid electrolytes with a buffer layer between them, along with separate patents covering electrode manufacturing and quality control methods.

The other patents deal with problems that show up once you try to actually build the thing at scale. One covers a cathode with two layers, a monocrystal inner layer that resists cracking under repeated charging, and a polycrystalline outer layer built for faster charge and discharge rates. Another adds an ionic liquid wetting agent to the electrode to fix a common issue in solid-state cells, where solid particles don’t make consistent contact with each other. A separate filing sets a manufacturing quality standard, requiring that at least 60 percent of a cathode particle’s surface stays in physical contact with the surrounding electrolyte particles, since inconsistent contact is one of the main reasons solid-state cells lose capacity after repeated fast charging. Full technical breakdowns of all six patents are available from electrive.com and CarNewsChina, which both reviewed the filings in detail.

Why this matters, and why it’s not close yet

BYD currently builds its EVs around the Blade LFP battery, which is safe and structurally efficient but comparatively dense and heavy. Solid-state chemistry, in theory, lets a car carry more usable energy in a smaller, lighter pack, which is the whole reason every major battery maker is chasing it. BYD’s own battery division has said the cathode active material share in its solid-state design already exceeds 85 percent, which is a meaningful technical milestone, but getting a lab result to work reliably across millions of manufactured cells is a completely different problem.

That gap between lab progress and mass production is exactly what CATL, the world’s largest battery maker and BYD’s biggest rival, keeps pointing at. CATL chairman Robin Zeng said in a June this year that CATL’s own solid-state programme sits at level four out of nine on its internal technology readiness scale, and that mass commercialisation, which CATL defines as reaching production volumes above one million vehicles, is unlikely before 2030. Zeng expects the first commercial applications to land only in vehicles priced above roughly 250,000 yuan, close to €32,000, since the cost of getting the chemistry right will only make sense on higher-margin cars at first.

When will BYD’s solid-state batteries be ready?
BYD is targeting small-scale trial production in 2027, with early cells going into camouflaged test vehicles first rather than a commercial launch.

BYD isn’t alone in racing toward a 2027 target either. We looked at the wider picture, including China’s tax policy changes that are pushing manufacturers toward sodium-ion and solid-state cells, who currently dominates battery supply, and where Europe stands by comparison, in our piece on the next-generation battery race. BYD’s own LFP technology is explained in more depth in our LFP vs NMC battery breakdown.

So 2027 is realistic as a date for small-scale trial production, in the sense that BYD will likely have some solid-state cells running in test cars by then. It’s a much bigger jump from there to a solid-state battery you can actually buy in a production car at a normal price, and even BYD’s biggest domestic rival is telling anyone who’ll listen that this is still years away.

Is solid-state battery technology ready for mass production?
No. CATL chairman Robin Zeng said in June 2026 that CATL’s own solid-state programme is at level four of nine on its technology readiness scale, and that mass commercialisation above one million vehicles is unlikely before 2030.

Featured Image Credit: BYD