Finnish battery startup Donut Lab just released the first independent validation of its solid-state battery tech, and the results back up the company's bold claims. After months of skepticism following its early-2026 announcement, the startup partnered with state-owned VTT Technical Research Centre of Finland to test charging speed and thermal performance. The results, published today, show the battery hitting fast-charge targets while maintaining stable heat levels - a critical milestone for a technology that's tripped up bigger players for years.
Donut Lab isn't backing down from the skeptics. The Finnish battery startup that turned heads in early 2026 with claims of a production-ready solid-state battery just dropped its first set of independent test results, and they're designed to silence the doubters.
The VTT Technical Research Centre of Finland put Donut Lab's battery through charging speed and thermal behavior tests, according to test documentation released today. For an industry that's watched countless solid-state promises fizzle out in the lab-to-production valley of death, third-party validation isn't just nice to have - it's essential.
The results show the battery maintaining stable thermal performance during fast-charging cycles, addressing one of the biggest production headaches that have kept solid-state tech trapped in research labs. Traditional lithium-ion batteries generate significant heat during rapid charging, requiring complex cooling systems. Solid-state designs promise better thermal management, but proving it at scale has been the stumbling block.
Donut Lab announced its breakthrough earlier this year, claiming it had cracked the production puzzle that's eluded bigger players. The company said it could manufacture solid-state cells using existing battery production infrastructure - a claim that raised eyebrows across the industry. Toyota, Samsung, and have all pushed back their solid-state timelines multiple times, citing manufacturing challenges.
