Donut Lab has published results of its third independent test measuring self-discharge characteristics of its solid-state battery, known as the Donut Battery. The report, now available on the I Donut Believe website, addresses speculation that the technology functions as a supercapacitor rather than a battery. In the test, researchers evaluated the cell’s ability to hold charge over extended periods under controlled conditions.
According to Ville Piippo, CTO at Donut Lab, “Supercapacitors charge and discharge quickly, but they also lose their charge quickly when not in use. The Donut Battery behaves like a battery and can maintain a charge for significantly longer.” The test protocol began, as in previous evaluations, with a 1C capacity measurement to verify consistency across sample cells. Following this, the cell was charged to approximately 50 percent state of charge and left connected to a laboratory battery tester at room temperature for ten days, with cell voltage recorded every ten seconds.
Data from the first ten hours showed initial voltage stabilization, after which the voltage curve continued to level out gradually over the remaining nine days. A final discharge at the end of the period confirmed that the observed voltage drop corresponded directly to the energy loss in watt-hours. These results align with expected battery behavior and contrast sharply with the linear, more rapid voltage decline characteristic of supercapacitors under similar conditions.
The third test reinforces earlier findings on the Donut Battery’s performance and paves the way for further validation steps ahead of production integration in electric vehicles.
Source: I Donut Believe
