A major breakthrough in battery technology may be closer than expected. Donut Lab has released new independent test results showing its solid-state “Donut Battery” not only withstands extreme heat—but actually performs better under it.
The second round of testing was conducted by the globally respected VTT Technical Research Centre of Finland, which evaluated how the battery operates in high-temperature conditions. The findings could have major implications for electric vehicles and other high-performance technologies, where overheating has long been a critical challenge.
Traditional lithium-ion batteries typically begin to struggle at temperatures between 60 and 70 degrees Celsius. Beyond that range, the risk of damage increases, performance declines, and in worst-case scenarios, thermal runaway—a dangerous chain reaction—can occur. The Donut Battery, however, is built differently. It uses a solid-state design that eliminates flammable liquid electrolytes, allowing it to safely operate at much higher temperatures.
During testing, the battery was exposed to conditions of 80 and 100 degrees Celsius. Researchers measured its capacity and efficiency through controlled charge and discharge cycles, simulating real-world stress scenarios. The results were striking.
At 80 degrees Celsius, the battery delivered up to 110% of its normal capacity, performing even more efficiently than it does at room temperature. At 100 degrees, it still reached approximately 107% capacity while maintaining stable operation. Even after prolonged exposure to extreme heat, the battery continued to function normally and returned to its original charge capacity once cooled.
According to Donut Lab’s Chief Technology Officer, Ville Piippo, the improved performance is due to reduced internal resistance at higher temperatures, which allows for smoother energy flow and less voltage drop during discharge.
Equally important is what didn’t happen. The battery showed no signs of degradation, instability, or safety issues—even at 100 degrees Celsius. While the outer pouch lost its vacuum at the highest temperature, the internal components remained fully operational.
The results mark a significant step forward for solid-state battery development, a field widely seen as the future of energy storage. By demonstrating both durability and enhanced performance in extreme conditions, the Donut Battery addresses one of the biggest limitations of current battery technology.
As industries push for safer, more efficient energy solutions, Donut Lab’s innovation could help pave the way for longer-lasting electric vehicles, more resilient electronics, and a new standard for battery safety in high-temperature environments.