Donut Lab’s battery charges as promised, but not all promises have been proven yet

Donut Lab has published its first measurement results of its solid-state battery. According to the preliminary results, the charging speed of the battery turns out to be equal to Donut Lab’s hard promises. The battery is said to have been charged at its best in the 11C test to 80 percent in 4.5 minutes and fully charged in more than seven minutes.

As promised, Donut Lab also announced VTT’s test report on their website. In the report, a real battery has actually been tested in VTT’s laboratory.

According to the release, the measurements started with a standard 1C discharge capacity measurement, followed by quick charge tests at 5C and 11C rates and both cooling configurations.

The measurement results correspond quite closely to Donut Lab’s original claims, and are clearly better than any current commercially available lithium-ion battery.

In the company’s press release, Donut Lab’s technology director Ville Piippo comment on the measurements as follows:

“Unlike other solid-state batteries, which require high compression pressure and suffer from volume changes of up to 15-20% during charging cycles, Donut Battery does not require special compression or extensive cooling. This significantly simplifies the structure of the battery packs and enables a cost-effective, high-performance solution that exceeds traditional lithium-ion batteries in terms of energy and power density,” says Ville Piippo.

In other words, with this test Donut Lab wanted to show how well it behaves at high temperatures compared to other solid state batteries. Donut Lab’s Piippo justifies that bulky active heating systems do not need to be implemented around this battery cell.

Now only the download speed was tested

In the first VTT measurements, only the charging speed of the Donut Lab battery was tested. Although the results are impressive and correspond to the original promises, these results alone do not justify all of Donut Lab’s claims.

Research and development manager of Seinäjoki University of Applied Sciences Juho Heiskan according to Donut Lab must be able to demonstrate that one and the same battery cell charges as currently shown in VTT’s tests, also lasts the promised 100,000 cycles, also manages in the cold as promised and at the same time fulfills the promise of 400 Wh/kg.

“The charging speeds of the battery are really convincing, I have to admit. The test result resembled the measurement results of the original announcement, but with better data. However, with a hard 11C charge, the battery got really hot, which means the resistance in the battery”, Heiska recently assessed.

“The charging curve of the battery corresponds to a lithium-ion battery, Heiska states. This is a bit special, because Donut Lab has also claimed that the battery does not contain lithium at all. Instead, one important piece of information, i.e. the energy density, was left out of the studies.”

“In these first tests, it has not yet been determined what the cell’s energy density, i.e. Wh/kg, is. I wonder a little why they have not been published now,” Heiska says of VTT’s report.

Not all claims can be evaluated

Also professor of battery chemistry and materials at Aalto University Tanja Kallio states that it is not possible to draw comprehensive conclusions from individual tests. Before the announcement, Kallio commented on the possible results as follows:

“Probably an independent tester, e.g. a research institute, does their work carefully. It’s a different matter what starting information they were given about the batteries and what kind of test series they were paid for – that is, based on the tests carried out, can you really evaluate all the claims as correct”, Kallio assessed.

Proving 100,000 cycles difficult

One of the most incredible claims of the Donut Lab battery is that it is capable of no less than 100,000 cycles. Now, in the first tests, this information has been made public. However, testing 100,000 cycles cannot be done quickly in a laboratory, says the research and development manager of Seinäjoki University of Applied Sciences Juho Heiska.

“The most common way to measure the cycle resistance of a battery is to measure it with a one-hour discharge and charge program. With the test in question, testing 100,000 cycles would take 22 years. If the promised 5-minute charge and discharge program is used, the test would take a couple of years. So it is quite clear that it has not been properly tested, but the result has been extrapolated from somewhere,” says Heiska about battery testing.

Heiska says that the cycle resistance of the battery can be predicted with the coulombic efficiency test. According to the TEPA term bank, one coulomb means one ampere-second (As).

“The Coulombic efficiency should be extremely high in order for 100,000 cycles to be possible. Current batteries achieve an efficiency of 99.99 percent, but to achieve 100,000 cycles it should be 99.9998 percent. Even if it is only in decimals, the jump is the same as from ten to a thousand”, Heiska explains the battery life testing.

Heiska says that the test mentioned above is used to find out how many electrons are lost during the cycle.

“Already with a thousand cycles, the total battery life can be predicted quite well,” states Heiska.

Your own narrative

Donut Lab’s way of announcing VTT’s test results independently shows that the company is trying to fully control its own narrative, i.e. its story. Donut Lab shouldn’t really be blamed for that, because any company that protects its own brand does this. However, it must be understood that Donut Lab would hardly publish anything negative about its own battery on its own initiative.

Donut Lab published VTT’s report as promised on its idonutbelieve website, for which points must be given.

To achieve maximum credibility, Donut Lab would have announced all laboratory results together with VTT at once. However, that’s not what Donut Lab set out to do.

The next test result will be published a week from now on Monday 2.3. at 15:00. In this way, Donut Lab skillfully maintains its narrative and media attention.

“Big turn”: New information about Donut Lab’s uproar – Should the Nordic countries unite? See Friday’s Financial MorningNew information about Donut Lab’s stock options: Related party paid one cent, investors up to 300 eurosDonut Lab already did something extraordinary