China Leads World’s First IEC Standard for EV Solid-State Batteries

On August 21, China’s State Administration for Market Regulation confirmed that a China-led proposal — “Solid-state battery application guide, test items and conditions for electric vehicle traction secondary lithium-ion batteries” — had been approved at the International Electrotechnical Commission (IEC). It is the world’s first international standard for solid-state batteries. France, South Korea and Japan joined the drafting. The move exports a Chinese national standard that took effect in July 2026 to the global stage, handing the industry a single “ruler” for what counts as solid-state.

A ruler for the next battery

Solid-state batteries are widely seen as the next major step for lithium-ion cells: longer range, higher safety and more stable performance than today’s liquid-electrolyte packs. Until now, no one agreed on how to measure them. The new IEC standard sets out clear testing specifications so that automakers worldwide — and the suppliers selling to them — work to one definition rather than a patchwork of national or corporate claims.

In practice, that means a future solid-state cell developed in Stuttgart, Seoul or Detroit will be judged against a methodology China wrote. For an industry where “solid-state” has been used loosely in marketing, a shared benchmark is a meaningful piece of soft power.

From national standard to IEC in under a year

China moved fast because the groundwork was already domestic. In December 2025 it published the world’s first national solid-state battery standard draft; that standard took effect in July 2026. Its most talked-about rule is a hard gate: a battery must survive six hours at 120 °C with a weight loss of no more than 0.5% to earn the “solid-state” label. Validation testing showed true all-solid-state samples came in below 0.5%, while mixed solid-liquid (semi-solid) cells measured between 1.68% and 10.33% — explicitly outside the definition.

The IEC approval landed less than two months after the Chinese national standard took effect. The sequencing is the point: China built the rule at home, then carried it to the IEC table with France, South Korea and Japan at the table.

Why China can lead

The leading position is backed by patents. In 2025, Chinese entities published 6,312 all-solid-state battery patents — about 44% of the global total — surpassing Japan’s 3,331, according to figures cited by academician Ouyang Minggao. By March 2026, more than 38,000 solid-state patents had been published worldwide, with Chinese applicants holding roughly 34%.

The strategy is pragmatic. China is commercializing semi-solid batteries first — a transitional chemistry compatible with existing production lines — then advancing to all-solid-state on the back of the world’s largest EV market. CATL is focusing on the sulfide route with a target of 400 Wh/kg for automotive cells, while BYD plans to begin pilot all-solid-state installation in 2027.

The reality check

The standard is a marker of intent, not a finished product. Ouyang Minggao has repeatedly cautioned that mass production remains three to five years away: test vehicles should appear in late 2026 or 2027, but scale is a 2030 horizon. He lays out three generations — graphite or low-silicon sulfide cells at 200–300 Wh/kg through 2027; high-silicon sulfide at 400 Wh/kg by 2030; and lithium-anode cells targeting 500 Wh/kg around 2035.

Japan and South Korea still hold strong core patents, particularly Toyota, with roughly 1,800 patent families in the field. Toyota’s commercialization has slipped repeatedly, but the intellectual-property position means China leads on volume and standards while rivals retain leverage on foundational chemistry. For context on the wider battery landscape, see our global EV battery market share analysis.

Author’s Take

China’s solid-state battery standard: frequently asked questions