VTT Test Donut Lab Battery Reaches 80% Charge in Under 10 Minutes [pdf]

This doesn't really follow the usual battery scam pattern, does it?

Like, EEStor or Nikola with big claims, timelines pushed years out, raise a ton of money, delay forever. Donut announced at CES and said bikes ship Q1 2026 which is weeks from now. They've raised ~€25M total (QuantumScape has burned through $1.5B+). And apparently they're not doing a big fundraise right now either.

If it's a scam it seems like a really bad strategy? You're basically setting a timer on your own credibility.

I've been reading around and the thing I keep landing on is the Nordic Nano connection. They're a Finnish nanotech company Donut invested in, and they published specs for a "bipolar electrostatic capacitor" with basically identical numbers - 400 Wh/kg, 100k cycles, fireproof. Does anyone with more battery knowledge know if this could be some kind of supercapacitor hybrid being marketed as a solid-state battery? The VTT report confirms fast charging works but doesn't say anything about energy density, cycle life, or what this thing actually is.

Seems like the energy density and cycle life reports (supposedly coming in the next few weeks) are going to be way more interesting than this one.

The weirdest tech story in Finland right now.

The founders have sketchy track records. They do a carefully managed social media build-up. There are credible rumors that they’ve been simultaneously raising money by cold-calling moderately wealthy people around the country. (Finland has extremely little oversight for private fundraising; you can basically sell shares in your zero-revenue startup to grandma next door — as long as you’re careful about wording your claims as “projections”.)

So lots of red flags. Everyone would love it to be real of course because it’s been a long since Finland’s tech scene had a global hit like Nokia and Supercell… And perhaps the Donut founders are counting on that mood.

Here's the CEO Marko Lehtimäki selling his magic AGI: https://www.youtube.com/watch?v=ilgJKjiDLV8 :D

He's been a busy beaver!

Apparently the first 3rd party test was on fast charging and the 3rd party is VTT, which is the government affiliated(owned?) "VTT Technical Research Centre of Finland"

The people listed on this report appear to be on LinkedIn, so I guess it will be easy to confirm if the test document is authentic.

The announcement of the test: https://youtu.be/d2QU_LpkSPs

Hopefully, soon we will find out if this seemingly "too good to be true" is a revolution or something else.

First report for Donut lab battery is out. Here is the TLDR

Specs

    26 Ah nominal capacity at 1C discharge rate

    94 Wh nominal energy with 3.6V nominal voltage

    Operates within 2.7V – 4.15V recommended range (max charging to 4.3V)

    5C charging (130A): 0-80% in ~9.5 minutes, 0-100% in ~13.5 minutes

    11C charging (286A): 0-80% in ~4.9 minutes, 0-100% in ~7.3 minutes

    Successfully delivered 98.4-99.6% of charged capacity even after extreme 11C charging

    Tested with both one-sided and two-sided heat sinks to simulate real-world conditions

    With dual heat sinks: Peak temps of 47°C (5C) and 63°C (11C) — well within safe limits

    With single heat sink: Reached 61.5°C (5C) and up to 89°C (11C) — still functional but approaching thermal limit

    Energy density: No weight and volume was mentioned

    Cycle life: VTT ran only 7 test cycles total.

    Cost Claims: Nothing about cost is mentioned

    Material Claims: No chemical analysis or materials analysis.

    Extreme Temperature Performance: No cold weather testing. No high-temperature testing.

    No abuse testing: No nail penetration, no overcharge, no short-circuit, no crush tests.

Good to have a VTT report confirming the charging speeds, but the actual differentiator would be the energy density I guess, given that BYD has already proven <10min charging with an LFP battery in an actual car. (https://volta.foundation/battery-report-2025/ pg. 161)

The massive amount of production-oriented research in solid state and semi solid state batteries indicates to me that this stuff is coming soon in a big way. I've been curious about buying an electric car recently, and if I buy one right now it would only be a used one, don't want to fully invest in something about to be obselete.

Would be nice if they added some more detail about the battery like dimensions and weight, or did I miss that part.

Fairly important bit here at the end:

> This project included independent charging performance tests on the energy storage devices supplied by the customer, which the customer identified as solid-state battery cells.

> which the customer identified as solid-state battery cells.