Donut Lab’s Solid-State Battery: First Test Results Revealed
▼ Summary
– Finnish startup Donut Lab released an independent test showing its solid-state battery can charge from 0-80% in about 9.5 minutes while retaining full capacity.
– The battery achieved this rapid charging using only passive cooling, unlike traditional lithium-ion batteries which require heavy, active cooling systems.
– Solid-state batteries are seen as a major advancement because they use dry, non-flammable materials and can hold more energy without the thermal risks of liquid electrolytes.
– The test did not confirm the battery’s chemistry or address the potential “dendrite issue,” a known challenge for solid-state batteries that can cause electrical shorts.
– Donut Lab claims its battery has a higher energy density and a vastly longer lifespan than current lithium-ion batteries, but these claims require further independent verification.
Finnish startup Donut Lab has released the first independent test results for its production-ready solid-state battery, aiming to address widespread industry skepticism. Conducted by the state-owned VTT Technical Research Centre of Finland, the evaluation focused on charging speed and thermal performance, revealing the cell can achieve an 0–80% charge in roughly 9.5 minutes while retaining full capacity. This performance could dramatically shorten EV charging stops, potentially making them comparable in duration to a traditional gasoline refuel.
The tests specifically examined the battery’s behavior under rapid charging without relying on complex active cooling systems. VTT employed a passive cooling setup, first sandwiching the battery between two aluminum plates and later testing it on a single plate. The goal was to prove the cell’s inherent stability and its ability to avoid the thermal runaway risks common in conventional lithium-ion batteries. Using C-rate measurements, where 1C equals a full charge in one hour, researchers pushed the battery to 5C and 11C charging rates. At 5C, the cell reached 80% state of charge in about 9.5 minutes and a full 100% in just over 12 minutes, with all of that charged capacity available upon discharge.
A notable challenge emerged during a test with only one cooling plate, where the battery temperature spiked to a 90°C safety limit, triggering an automatic shutdown. Investigators found the issue was poor physical contact with the cooling plate; once secured properly, heat dissipated effectively into the metal. Donut Lab’s Chief Technology Officer, Ville Piippo, emphasized this advantage, stating their design does not require high compressive pressures or extensive cooling unlike other solid-state technologies, which can undergo significant volume changes during cycling. This simplicity could lead to more cost-efficient and powerful battery pack structures.
Donut Lab claims its technology offers significant advantages over current standards, including an energy density of 400 watt-hours per kilogram and a lifespan of up to 100,000 charge cycles. For context, contemporary lithium-ion batteries typically offer 200–300 Wh/kg and endure 1,500 to 3,000 cycles. The specific unit tested by VTT, labeled “Solid State Battery V1,” had a capacity of 26Ah and a nominal energy of 94Wh.
However, the report leaves several critical questions unanswered. VTT did not independently verify the battery’s internal chemistry, accepting Donut Lab’s specifications at face value. More importantly, the tests did not investigate the dendrite issue, a known challenge where microscopic lithium growths can form across the solid electrolyte, leading to internal short circuits. The company indicates future independent tests, part of its “I Donut Believe” series, may address these concerns, but for now, the results highlight promising charging performance while underscoring that broader validation is still needed.
(Source: The Verge)
