The Finnish startup Donut Lab’s battery can charge from 0 to 80 percent in under 5 minutes, based on its first independent test. Earlier this year, Donut Lab announced a major breakthrough with its production-ready, solid-state battery, initially met with skepticism. To address doubts, they released the first independent test of their battery’s charging speed and thermal behavior. The test, conducted by VTT Technical Research Centre of Finland, showed that the battery charges significantly faster than traditional lithium-ion batteries. It achieved 0-80 percent charge in about 9.5 minutes while retaining full capacity, and in 4.5 minutes while retaining 99 percent capacity.
Solid-state batteries are sought after due to their potential to hold more energy without thermal issues. Unlike typical “wet” lithium-ion batteries, they use “dry” conductive materials, avoiding slow charging and hazardous issues. Donut Lab’s battery maintained nearly 100 percent energy potential after rapid charging, transforming EV charging sessions to 5-minutes similar to gas refueling. Unlike other EV batteries with active cooling systems, the test used passive cooling to demonstrate safety without a heavy cooling system. VTT measured charging rates significantly higher than typical without active cooling.
Donut Lab’s battery was charged successfully at 5C for over nine minutes, with full charge in 12 minutes. Testing exposed some issues with heat management, resolved by improving contact with cooling plates. Donut Lab CTO Ville Piippo stated that their battery simplifies pack structure and offers cost-efficient, powerful solutions with better density than lithium-ion batteries. With 400 watt-hours per kilogram capacity, Donut Lab’s battery claims to charge in under 10 minutes and last 100,000 cycles, surpassing current lithium-ion batteries’ cycle life.
However, key questions remain unanswered, including confirmation of the battery’s chemistry and addressing the “dendrite issue” that causes short circuits. Donut Labs plans further tests to provide additional insights.