Solid-State Battery Claims Put to Test

Donut Lab has released the first independent test results for its solid-state battery, confirming that it can charge from 0 to 80% in just 4.5 minutes at an extreme 11C rate. The results come from Finland's state-owned VTT Technical Research Centre, one of Europe's leading research organizations. However, the report only covers charging performance, leaving Donut Lab's most extraordinary claims completely unverified.

The test was conducted using a PEC ACT0550 battery tester in a climate-controlled chamber, with the cell being charged at two rates: 5C and 11C, using a constant-current/constant-voltage protocol up to 4.3V. Before and after each charge, the cell was discharged at 1C down to 2.7V to verify full capacity was available.

The charging speed results are legitimately impressive, with the 11C test reaching 80% state of charge in just 4.5 minutes, despite the surface temperature climbing to a peak of 63°C. However, this extreme rate is not something that most users will ever encounter in real-world applications.

But what's really interesting is how Donut Lab's marketing claims stack up against the measured reality. The company has touted its battery as needing no active cooling, but even passive thermal management with a single heat sink proved insufficient at 11C charge rates.

The VTT report addresses one claim and one claim only: fast charging. The specifications that drew the harshest industry criticism remain completely untested by any independent party: 400 Wh/kg energy density, 100,000 cycle life, and extreme temperature performance.

Donut Lab's claim of 100,000 cycle life is orders of magnitude beyond anything demonstrated in the industry, and its marketing claims about cost parity with lithium-ion batteries are also highly questionable.

The context for these results is important. Donut Lab unveiled this battery at CES in January, providing no live demonstrations, patent disclosures, or peer-reviewed research. Svolt Energy's chairman Yang Hongxin called it a 'scam,' stating that 'all the parameters are contradictory' and that 'any technician with basic knowledge would recognize it.'

Donut Lab CEO Marko Lehtimäki fired back, saying he was betting his personal reputation on the technology shipping in customer Verge Motorcycles within weeks. The company then commissioned VTT to independently verify its claims.

The results are being published through a dedicated website called 'I Donut Believe' and a video series that launched today. While this first report is a step in the right direction, it only addresses one claim and leaves many questions unanswered about the battery's performance and viability.

Ultimately, we'll need to see more comprehensive testing and verification of Donut Lab's claims before we can say for sure whether its solid-state battery is a game-changer or just another flash in the pan.