Donut Lab’s 5-Minute charge claim: what the tests show

Imagine stopping for a coffee and returning to a car that has recovered most of its range. That scenario moved closer to reality in February 2026 when Donut Lab, a Finnish technology company, published independent test results for a new type of battery cell.

The tests were carried out by VTT Technical Research Centre of Finland, a state-backed research organisation. They confirmed one standout claim: the cell charged from empty to 80% in just 4.5 minutes. A full charge took just over seven minutes. Afterwards, between 98.4% and 99.6% of that stored energy was available for use.

To put that in context, most EV batteries today take 30 to 60 minutes to reach 80% at a public fast charger. Donut Lab’s cell achieved its speed without any fans, pumps or liquid cooling, using only simple aluminium plates to absorb heat.

What makes this battery different?

Today’s electric cars use lithium-ion batteries, which store energy using a liquid chemical solution inside each cell. Donut Lab’s battery is what engineers call a “solid-state” design. It replaces that liquid with a solid ceramic material.

Why does that matter? The liquid in conventional batteries is flammable, which is why EVs need complex cooling systems and safety features to manage heat. A solid material removes that fire risk at source. It can also, in theory, store more energy in less space and accept a charge more quickly.

Donut Lab says its ceramic material allows charged particles to move through the battery almost as fast as they do in liquid-based cells, but without the overheating risks. The company claims its cells can store around 400 watt-hours of energy per kilogram of weight, roughly double the figure for many current EV battery packs.

What did the tests actually prove?

The VTT tests focused on two things: how fast the cell charges, and how it handles heat.

On charging speed, the results were clear. The cell reached 80% in about 9.5 minutes at a moderate charging rate, and in 4.5 minutes when pushed to its maximum speed. No active cooling was used in either test. Electrek reported that this puts Donut Lab ahead of most competitors developing solid-state batteries.

A second round of VTT testing, published on 2 March 2026, looked at how the cell performs in extreme heat. At 80°C, it actually delivered more energy than at room temperature. Even at 100°C, it continued to function without damage. Conventional lithium-ion cells can become dangerous at those temperatures.

What has not been proven?

This is where the picture becomes more complicated. The charging speed is confirmed, but the claims that matter most to the EV industry remain unverified.

First, energy density. This is a measure of how much energy a battery stores relative to its weight. A higher figure means a lighter battery for the same driving range, or more range for the same weight. Donut Lab claims 400 Wh/kg, but VTT did not weigh the cell. Without that measurement, the claim cannot be checked. Electrek’s analysis calculated that the cell would need to weigh about 235 grams to hit that figure.

Second, lifespan. Donut Lab claims its battery can survive 100,000 charge-and-discharge cycles. A typical EV battery today lasts between 1,000 and 5,000 cycles. The VTT tests covered only a handful of cycles, nowhere near enough to test this claim.

Third, heat management at full scale. During one test using a single cooling plate, the cell’s surface temperature hit 90°C and the test was temporarily stopped. Donut Lab markets the battery as needing no active cooling, but managing heat across hundreds or thousands of cells in a full car battery pack is a different challenge entirely.

Why are some experts sceptical?

The combination of claims, ultra-fast charging, extreme energy density, a 100,000-cycle lifespan, and low cost, is unlike anything the battery industry has seen from a small startup. When Donut Lab presented these figures at the CES technology show in January 2026, the reaction from established players was blunt.

CATL’s head of off-China operations called the claims “clearly fake.” Svolt’s chairman described the energy density figure as “physically impossible.” Finnish investor Aki Pyysing was even more direct in his assessment. The company also drew scrutiny for approaching small individual investors with promises of large returns, rather than securing backing from major institutional funds.

Supporters point out that the VTT data at least confirms the cells exist and charge as claimed. That alone is more than many solid-state battery announcements have delivered.

When could drivers actually benefit?

Donut Lab grew out of Verge Motorcycles, a Finnish electric motorcycle company. Verge plans to use the battery in its TS Pro model, which it says will offer up to 600 km of range with charging in under 10 minutes. Deliveries were originally planned for early 2026, though reports suggest volume production may slip into late 2026 or 2027.

Beyond motorcycles, Donut Lab has announced partnerships for lightweight car platforms, smart trailers and defence vehicles. It says more than 200 vehicle manufacturers are in discussions. Major battery makers including Toyota, Samsung SDI, CATL and BYD are targeting 2027 or later for their own solid-state cells. If Donut Lab delivers first, it would mark a significant moment for the technology.

What would this mean for everyday EV owners?

If the full range of claims holds up in finished vehicles, the day-to-day experience of owning an electric car could change noticeably. Charging would feel more like a brief fuel stop than a planned break. Cars could travel further on a lighter battery, or use the weight saving to improve handling and efficiency. The removal of flammable liquids would also improve safety.

The gap between a single cell in a laboratory and a finished battery pack in a car is, however, substantial. Manufacturing thousands of cells consistently, keeping costs competitive, and integrating them into real vehicles are all hurdles that have tripped up battery startups before.

The VTT results give the industry a credible reason to pay attention. What comes next, verified energy density, proven durability, and vehicles on the road, will determine whether Donut Lab’s promise becomes an EV driver’s reality.