Finnish Startup Donut Lab Validates Solid-State Battery Performance at -30 Degrees Celsius
Independent tests by VTT Technical Research Centre confirmed the battery retains 99% capacity in extreme cold without thermal management systems.
Finnish startup Donut Lab has released independent validation data showing its solid-state EV battery retains 99% of its capacity at -30 degrees Celsius (-22 degrees Fahrenheit), challenging common criticisms regarding electric vehicle performance in extreme cold.
What Happened
Donut Lab, which unveiled its solid-state battery at CES in January claiming 400 Wh/kg energy density and a five-minute charge time, has now published results from tests conducted by the VTT Technical Research Centre of Finland. The latest report details a module consisting of 14 battery cells placed in a temperature chamber at -30°C for five hours. After the module was completely frozen through, tests showed it retained 99% of its capacity compared to measurements taken at +25°C. Donut Lab emphasized that the testing process did not include any heating, cooling, or insulation systems. CTO Ville Piippo stated that the battery remained unaffected despite the elimination of typical advantages, noting that 'A typical lithium-ion battery would struggle to provide power, even for a brief moment, in such cold temperatures.'
Why It Matters
The validation addresses a persistent barrier to EV adoption: the perception that battery range and power degrade significantly in winter conditions. While cold weather also impacts the fuel efficiency of internal combustion engines, Donut Lab’s data suggests a path toward batteries that are inherently resilient to temperature extremes without relying on complex external thermal management systems. This development comes amid a broader industry shift, with manufacturers like GM and Ford exploring new chemistries such as Lithium Manganese-Rich (LMR) and Lithium Iron Phosphate (LFP) to balance cost and performance. Donut Lab’s performance at 100°C, validated in a previous VTT report, further distinguishes its technology from standard lithium-ion batteries, which typically suffer from outgassing and fire risks at such high temperatures.
The Bottom Line
Donut Lab continues to withhold specific details about its battery chemistry, maintaining an air of mystery while providing step-by-step third-party validation of its performance claims. The company asserts its technology is ready for OEM vehicle manufacturing, positioning itself as a potential alternative to established lithium-ion supply chains as the industry seeks to improve cold-weather reliability and energy density.
