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

https://pub-fee113bb711e441db5c353d2d31abbb3.r2.dev/VTT_CR_00092_26.pdf

by sagyam • 5 months ago

114 122 5 months ago

pub-fee113bb711e441db5c353d2d31abbb3.r2.dev

interstice• 5 months ago

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

dagurp• 5 months ago

You can take a look at the announcement video https://youtu.be/Y-aPS2AwMbc?si=RD4Ja8tJggLPgXGj

coffeebeqn• 5 months ago

The pdf also has a picture of it where you could possibly reverse Engineer the dimensions based on the other things in the picture. Looks very flat like an iPad battery

mrtksn24• 5 months ago

That was previously announced and CES and was described as "can be any shape and any size and any voltage within a reason".

ghm2180• 5 months ago

It seems From the video they don't look much bigger than a cellphone.

mrtksn24• 5 months ago

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.

kevlened• 5 months ago

They also published the report here: https://pub-fee113bb711e441db5c353d2d31abbb3.r2.dev/VTT_CR_0...

That's the same link. Is there a way to attest that this is an official VTT report?

mrtksn24• 5 months ago

Sorry, I was trying to compose a post but I was a minute late so copy-pasted the content as a comment and forgot to adopt. Removing the redundant link. Thanks.

BTW, the people who conducted the test appear to be on LinkedIn. I guess its pretty easy to confirm if the test on the company site is authentic.

andor• 5 months ago

The PDF is digitally signed with a cert from the Finnish „Digital and Population Data Services Agency“

jusssi3• 5 months ago

The person whose signature is on it, is listed on VTTs website with the same title.

Considering the amount of publicity this thing gets, VTT or the person will publicly refute it pretty soon if it's a fake.

vipulbhj• 5 months ago

I’ve been digging into the data (using Gemini and a few other sources). The claims behind https://idonutbelieve.com/ are pretty bold. I’d like to be optimistic, but I’m going to wait for more independent verification before drawing any conclusions.

mrtksn24• 5 months ago

I desperately want this to be real but LK-99 thought me to be skeptical of big announcements. AFAIK the Finnish media went brutal on them and science YouTubers reported some rumors about sketchy stuff but they seem to be rolling so far.

VTT appear to be a solid institution, so we will find out soon I guess.

scoot• 5 months ago

Fast charging, long life, low cost – pick two.

Actually, there are a bunch of other variables (energy density, stability, discharge current, etc. etc.), so the probability of a technology that improves one significantly without negatively affecting at least one other is vanishingly small. Hence the number of overhyped battery technologies that get reported but never productised.

rmu092• 5 months ago

They claim not only fast charging, long life and low cost, but also very high energy density, no degradation in low temperature, no thermal runaway, non-hazardous materials and no "geopolitical" needed.

patapong2• 5 months ago

Careful though, this test explicitly only tests the charge and discharge capabilities of the battery, not whether it's a solid state battery or not. According to ChatGPT, these results would in theory also be possible with a normal Li-ion battery. I am really hoping this is real though! And waiting for further tests.

piyh• 5 months ago

FPV lipo batteries can charge at 5c all day, you might be able to get away with 11c for a few charges before degradation or becoming spicy. Agree that this proves nothing useful.

doikor2• 5 months ago

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"

It is a govenrment owned non-profit company.

As one of its services it will independently verify your product/invention/whatever works as claimed (for a bunch of money).

https://www.vttresearch.com/en

xienze3• 5 months ago

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.

make_it_sure• 5 months ago

why?

xienze3• 5 months ago

Because that's not independent verification that the device tested actually _is_ a solid state battery. Just that whatever was tested had certain charging characteristics.

bizzleDawg• 5 months ago

It's almost like there an implied "wait for part 7 guys and remember to like and subscribe"

mech998877• 5 months ago

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.

fhdkweig2• 5 months ago

I make the same argument when I buy a computer. If I just wait a little longer, there will be a faster cheaper version of what I can buy today. When buying anything that depreciates, the best strategy is to wait (possibly forever) and only buy when you really need it now.

yomismoaqui2• 5 months ago

Until you wait too much and end in a RAM shortage period due to AI...

zemvpferreira• 5 months ago

“Soon” is likely 5-10 years easily though.

stetrain2• 5 months ago

The whole industry is always working on improved batteries. But it's a long road from lab-scale to mass production, and often improvements in one area have downsides in another.

New generations of cells that improve energy density usually start out more expensive than existing chemistries, so they show up at the high end of the market first and work their way down.

If we do get truly improved solid-state batteries available in EVs in the next 5 years, it will likely start at the high end of the market and work its way down over many years to cheaper segments as production capacity ramps up. The base model EVs aren't going to suddenly have their batteries swapped out with ones that are twice as good for the same price.

sagyam• 5 months ago

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)

What was verified

    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

Thermal Management

    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

Missing claims

    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.

But according to the company website another report will drop next monday (March 2nd).

taneq2• 5 months ago

It’s good to know that it does at least perform about as well as current conventional batteries. The energy density and cycle life were the really off-the-wall claims. It’s exciting to hear that they’re continuing to test, can’t wait for more third party results!

Edit: Reading the report, they talk about “charge capacity” (Amp hours in/out) efficiency of 98.4% to 99.6%, but this seems potentially misleading. The actual charge energy efficiency is more like 90%.

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

Note the Wh numbers for discharge vs. charge energy.

Discharge capacity Charge capacity Discharge energy Charge energy
Cycle 1 26.109 Ah 26.159 Ah 91.021 Wh 100.793 Wh

cogman10• 5 months ago

Yup, those 2 are the ones I really want to see.

The energy density isn't out of line if this is a true solid state battery. The cycle life, though, is AFAIK. I don't believe solid states have that sort of cycle life.

PoignardAzur3• 5 months ago

Energy density: No weight and volume was mentioned

Note that the report includes some photos of the battery, so we can assume that it's not, like, several orders of magnitude larger than what they advertised.

EDIT: Honestly, I'm pretty excited. Even if their promises on cost and materials don't pan out and the lifetime turns out to be terrible, what they've just demonstrated is already a game-changer.

hipsdontlie5• 5 months ago

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

He's been a busy beaver!

skrebbel2• 5 months ago

Srsly. So it's all bogus then?

hipsdontlie5• 5 months ago

Yep, so it seems!

patapong2• 5 months ago

Thank you for sharing this, relevant context...

mrtksn24• 5 months ago

I don't know about that, the last 4 years everyone is selling magical AI and AGI is around the corner. Including every single top 10 rich people.

Was this AI proven to be any more fake Than Sam Altman, Elon Musk or Dario Amodei's one? Did he took similar level of money and delivered less than the promised?

What's the scam exactly? They don't seem to claim AGI anyway, they say Artificial Super intelligence which is like every AI company claim.

You seem to be on a mission against this CEO, maybe you can clarify a bit more about the scams you believe he is committing?

vardump4• 5 months ago

ASI is one step higher than AGI.

latchkey• 5 months ago

Audio emdash

Havoc• 5 months ago

oh that's a great insult

audunw2• 5 months ago

It should be said that in the LinkedIn post announcing this the clams are much more moderate. Like “10% along what we consider to be AGI” and “lots of work left to do” if I remember correctly. How is that different from any other R&D company working on AI? They all claim to be on the path to AGI in some form

pavlov• 5 months ago

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.

hipsdontlie5• 5 months ago

It's disappointing that this merry band of serial scammers are tarnishing Finland's reputation.

jusssi3• 5 months ago

It's also a bit sus that someone creates an account just to bash them, when they themselves are already doing a great job to make it look like a scam.

mrtksn24• 5 months ago

Can you plase give more information about the scams(not opinions about scam but actual scams where he was exposed) this guy committed?

doikor2• 5 months ago

The electric motorbike company (Verge Motorcycles) owned by the same people also has such bad accounting/paperwork that they could not find an auditor willing to give an opinion.

https://yle.fi/a/74-20205916 (article in Finnish)

"According to the auditor's report, no opinion was given on the company's financial statements because sufficient audit evidence was not available."

The company claims to have a couple million in inventory but no system saying anything about what is in their inventory, 300k in revenue in Finland without any papertrail of it actually happening, 2.5 million in R&D without any explanation/papertrail on what it was spent on (salaries? materials? machines?), etc.

Also the company has taken really expensive loans from family members of the leadership (12% interest which is way over the market rate).

idontwantthis2• 5 months ago

But the motorcycles do exist and use these batteries don’t they?

Has no one bought one and torn it open yet?

bmvw2• 5 months ago

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)

donny2018• 5 months ago

BYD has already proven <10min

BYD needs to be heavily liquid cooled/thermally managed to achieve that. The Donut battery only had metal heat sink on two or even one side - and its performance was even higher at high temperatures. LFP doesn't behave like that, I think?

bmvw2• 5 months ago

Agree, didn't notice that at first in the results, it would potentially allow for less thermal management and even more density at pack level. Curious to see if VTT will also publish a report on the cycles.

Dockson• 5 months ago

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.

Hamuko2• 5 months ago

Yeah, if it's a scam, at least we don't have to worry about it for too long. If we don't have third-party test results and/or the bikes in testers' hands in the next 37 days, then we can be pretty sure that it's just bogus.

skrebbel2• 5 months ago

I really want this to be true, but the founder launching AGI 9 months ago doesn't help their credibility a lot. And drip-marketing test results seems like a super weird thing to do, whether it's real or it's not.

Don't forget that a lot of scams aren't initially on purpose. Eg Theranos by all accounts very gradually morphed from a mild "fake it till you make it" scheme (mild by Silicon Valley standards at least) into a full-blown scam over years of growth and funding, the lies needing to be deeper and deeper over time to cover up the earlier ones.

I guess all I'm trying to say is the fact that it's a bad strategy for a scam, doesn't really mean it's not a scam.

Those Verge motorcycles appear to actually exist and work though, so that's a data point in favour of this being real.

mrtksn24• 5 months ago

the founder launching AGI 9 months ago

Yes, I want this too good to be true battery to be real and that's why I'm looking into such things but this claim is false.

He apparently launched "Artificially Superintelligence", which appears to be a marketing term for some architecture this company was working on. The "AGI" term seems to come from people who are going after this CEO.

I wasn't able to come up with people who claim that they were actually scammed, i.e. paid for a product that wasn't delivered or made an investment into something that doesn't exist.

This appears to be a much cleaner slate than the titans of AI. I'm inclined to believe that those alleged scams are not scams by SV standard.

qingcharles• 5 months ago

The founder reminds me of Kim "Dotcom", which worries me. I hope this thing is legit.

https://en.wikipedia.org/wiki/Kim_Dotcom

PoignardAzur3• 5 months ago

Does anyone with more battery knowledge know if this could be some kind of supercapacitor hybrid being marketed as a solid-state battery?

A few Youtubers have pushed the "if it's not a scam, it's probably a novel capacitor" hypothesis, but in their video announcing this test series last weekend, Donut Labs claimed "it's not a capacitor", so I don't know what's going on.

etyhhgfff• 5 months ago

The URL seems a bit dubious.

vardump4• 5 months ago

The PDF itself is signed.

WarmWash3• 5 months ago

Let me clear some things up as I have experience with places like VTT (but not VTT specifically) in my career.

VTT is a company that you pay to run tests for you. You bring them a product, tell them what tests you need done, and then they do them with honesty and expensive well calibrated gear. Frequently you also send engineers along with your product to provide on the spot support for the testing. It's very likely it was a Donut engineer who setup the cell, attached the heatsinks, adjusted the connections, etc. This is pretty standard, VTT just runs verified tests, they're not experts on your product. Then they give you an official honest report recapping the tests done and the results.

VTT is not an auditor for verifying claims, at least beyond the scope of the test you task them to do. They are a friendly business partner that you pay large amounts of money to for getting you verified tests done on your product.

I really cannot stress enough that VTT is not in it to disprove anything. It's incredibly suspect that in a battery capacity test, Donut did not have VTT verify cell weight or dimension. It's also important to understand that VTT would not request to do this either, because VTT just runs the tests you pay them to, as you tell them to do it. So if donut shows up with a different cell for each test, VTT would not skip a beat, because they are not auditing, they are just doing the tests they are paid to do.

Normally places like VTT thrive on compliance testing, where a regulation outlays the tests needed to be passed, and VTT provides the service of being the third party to run and sign off on those tests. Those tests are then submitted to the regulating body and they are the ones who pass/fail you, not VTT. They just do tests and collect money.

So Donut is writing their own "regulations" here, so they are just having VTT do whatever tests they want as they want them done.

The real test would be someone not affliated with donut taking one of these cells to VTT.

jlhawn• 5 months ago

It's incredibly suspect that in a battery capacity test ...

They would probably say this is because it's not a "battery capacity test" but a "charge performance test"

But I agree, when they eventually do have VTT perform a capacity test, how can we be sure that it's the same cell from the charge performance test?

verdverm• 5 months ago

how can we be sure that it's the same cell from the charge performance test?

I would imagine they will run the same tests again. Light testing for specific things during development or scaling, increased testing as you feel more confident in the product.

PoignardAzur3• 5 months ago

It's incredibly suspect that in a battery capacity test, Donut did not have VTT verify cell weight or dimension.

The report does include a few photos, and the battery does look pretty small on them? So I don't think there's foul play there.

WarmWash3• 5 months ago

Photos and "looks pretty small" are not technical parameters that you pay tens of thousands for a lab to certify.

There are a bunch of cutting edge cell technologies out there right now with gangbusters specs but have some kind of fatal flaw.

If Donut was serious they would put the full specs of the tested cell in each report, so people could have higher confidence that each tested cell is the same chemistry. VTT would have no issue weighing and measuring each cell before and after testing.

juleiie• 5 months ago

I have seen so much engineering scams over the years and this is precisely the thing that they all do.

It reminds me of E-cat. Anyone remembers cold fusion? They had same modus operandi. Lots of revolutionary claims but testing was so contrived and limited and lots of conditions that in the end no one was allowed to truly confirm it. .

This repeats the exact steps of that purported miraculous energy device.

ceoloide• 5 months ago

Since they are testers and not auditors, what prevents Donut Labs from changing the actual battery sent for testing, selecting whatever works best for that specific test? In aggregate each test would seemingly validate their claims, only nobody ever validated and audited the fact that the same exact battery was used in all the tests.

As many have said, so many red flags around something so exceptionally revolutionary that you'd need extremely strong and unquestionably real proof.

WarmWash3• 5 months ago

Nothing, that's why this comes off as largely performative and awfully suspect.

Let me put it this way - these labs are functionally pretty similar to a Qwest diagnostics or Lab Corp. Those places draw your blood and run tests on it. The prescription tells them the tests to do, and the doctor is the one who evaluates the results. The labs are just a dumb tool to do the testing as prescribed.

Donut in this case is writing their own prescription and then posting the results. Just like a lab, they don't interrogate you to see if you are manipulating your blood results. That's the doctor's job. And ultimately at the lab it's just a lowly tech going through the same motions they go through every day.

zormino• 5 months ago

Nothing prevents that, and the test lab wouldn't bat an eye at that. For all they know or care, you wanted to run different test on different cells. The only thing the lab is verifying is that the defined test was executed as stated, nothing else.

luka• 5 months ago

To clarify some misconceptions regarding what they do and don't have in their current motorcycles, as of Feb 2026:

All of current existing Verge motorcycles have a "traditional" lithium ion ~20kWh battery pack[0], very much on par with competition in all specs. They do exist and a few indeed appear to be in owners' hands (according to Facebook Verge fangroup posts and pics), and they can be test ridden. One of their showrooms is in Valley Fair in San Jose, CA. I have tested one of them. It feels and seems to perform well, as advertized and as physics allow, despite the hubless engine and skepticism around that. However, the test ride was ~30 minutes and there's so few of those bikes out there, that there's virtually no data on longevity.

What currently does not exist is a Verge motorcycle with the battery that they claim to be testing here. They have announced that all their offerings will feature their solid state battery later this year, increasing the energy capacity to ~30kWh. That remains to be seen.

[0] https://web.archive.org/web/20260223173926/https://www.verge...

archeopetrix• 5 months ago

Apart from metrics like energy density and cycle life, shouldn't we also consider idle self-discharge rate or charged-state longevity when evaluating batteries? No one seems to be talking about that in this case.

Animats• 5 months ago

It's nice that they have what they claim is a solid state battery. But having a small prototype isn't that big a deal at this point. All the major players have prototype solid state batteries that work. Nobody has volume production yet, and volume production seems to be hard and expensive, according to CATL and Samsung.

Mercedes has a test car with a solid state battery.[1] The battery is from Factorial Energy. There's only one such car, and they don't say how much it cost to make the prototype battery.

Ducati has a test motorcycle with a solid state battery.[2] The battery is from QuantumScape. There's only one such motorcycle.

Here's Fraunhofer IKTS making a solid state battery at lab scale.[3] The whole process is shown. Huge amount of effort to make one coin cell.

Samsung prototype.[4] Samsung has been talking about shipping tiny solid state batteries for wearables in 2026. Still too expensive for cell phones, which gives a sense of cost.

All the serious players can make a prototype by now. But the chemistry that's used for the prototypes may not be suitable for production. They have to balance capacity, weight, charge time, cycle life, manufacturing cost, and materials cost. (Samsung made a battery with a substantial silver content. It works, but that's not going to be a volume product)

These problems will be overcome, because throwing money at them works. The history of the tungsten-filament light bulb is worth reviewing. Making fine tungsten wire is very difficult. From 1913 to 2010, a huge plant in Euclid, Ohio, made most of the tungsten wire for light bulbs. There were a lot of process steps.[5]

[1] https://electrek.co/2025/02/24/mercedes-tests-first-solid-st...

[2] https://www.ducati.com/ww/en/news/ducati-s-electric-research...

[3] https://www.youtube.com/watch?v=j5SVrp8N-1M

[4] https://news.samsungsdi.com/global/articleView?seq=203

[5] https://www.youtube.com/watch?v=ZuhapGSexyg

Tuna-Fish• 5 months ago

Precisely. People are questioning the wrong things, I find it really easy to believe that Donut has a 400Wh/kg battery that can do 11C charging. Because that's something that can be easily externally verified, and they are sending that battery out to testers, and also because the existence of such a battery isn't new or shocking, many labs have prototypes in roughly the same performance envelope.

But that doesn't mean they have a winner, if the battery was ridiculously expensive to make. Their claims about cost are much more suspicious, and they have shown no proof about them.

ChrisArchitect• 5 months ago

Earlier source site: https://idonutbelieve.com/#third-party-evidence (https://news.ycombinator.com/item?id=47121442)

mrtksn24• 5 months ago

Ziroth, an engineering YouTuber who pursued academic career in the related fields believe that this must be high end lithium cell due to the characteristic similarities: https://www.youtube.com/watch?v=H45HXs4xXfA

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

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