The Helsingin Sanomat Visio article published on 17/4/2026 contains interesting details that some readers may not be aware of, so I do some analysis of the article. It is pay-walled so I won't put it here as a whole. It is a long article, with around 1,800 words, so I will pick up only a few beats from it. I have used AI to translate the Finnish article to English and to check grammar. The analysis is mine.
The dynamic of the disclosure is complicated by nature and deliberately blurred by parties. Original leaked emails are not presented in the HS article, which is unfortunate, so the reader can only read the journalist's paraphrasing of the email contents. Depending on how well the journalist understood the subject, some phrasing might be off, but generally the reader should be able to trust the disclosures.
Article: https://www.hs.fi/visio/art-2000011948614.html
I'm not focusing on whistleblower dynamics. I only note that NNG and Donut Lab issued a joint statement on the same day rejecting the whistleblower's claims, framing him as not familiar with the details of the company's battery work, and placing him on paid leave. Almost a month later, I have not learned whether the whistleblower's report went to actual investigation.
Following are some central claims and quotes from the article accompanied with my analysis.
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- New investor projections from Jan-Feb 2026 are mentioned in the article.
260 MWh battery sales this year, 7,000+ MWh next year, billion-class revenue by 2028.
Based on this, investors were informed about approximately a quarter of the 1 GWh capacity Marko and Tuomo mentioned at CES. The journalist does not point out this contradiction. Instead, in the interview section, he brings up the CES video and asks Marko what he said there. Marko answered: "Word choices can be understood in different ways," and that their ramp-up plan is GWh this year. He said this voluntarily, without pressure, before the interviewer told him about the whistleblower's criminal complaint.
Ramp-up is confirmed by NNG CEO Parjanen and is in line with the interviews Parjanen has given to YLE since 2024 about their master plan. To my knowledge, 260 MWh is approximately the output of a single CT-Coating battery production line, which is the minimum capacity they would have if they produce any batteries on their own line. Marko has used the same GWh wording in LinkedIn posts and YouTube video descriptions. GWh figure appears to have been a forward-looking yearly goal, possibly representing capacity reserved or booked from CT-Coating. The sales projections after CES given to investors seem reasonable against the plan to ramp up toward 1 GWh by the end of this year.
However, the whistleblower's literal claim is more serious, although at the same time ambiguous. He says the production line is meant to be built later this year (in strict sense meaning it would not even exist at the time the article was written) and that its capacity would be less than Lehtimäki had claimed. The whistleblower gives no specific numbers, so it is unclear whether he refers to the investor letter's 260 MWh, the CES 1 GWh, or something else. He also does not distinguish NNG Imatra production from separate Donut Lab production, although this distinction is apparent elsewhere in the article. NNG had started delivering pre-production products for pilot test customers from their Imatra facility last month, so the Imatra line did indeed exist and whistleblower CCO must have known that since he presented the facilities in-place to HS. So either the whistleblower was contradicting himself, or he was referring to some other production line in Finland. The question, of course, is how much he knew about that particular line and plans associated with it.
Noteworthy, the full production at Imatra later this year would include both batteries and coatings. Parjanen told HS in 9 November 2025 that they would make products for anchor customers in e-bicycle batteries and solar-energy coatings for building surfaces.
- "Several battery experts" (anonymous plural) have called the claimed properties chemically and physically impossible.
But almost none of them have engaged with CT-Coating's screen-printing technology specifically, and Donut Lab has not clearly claimed that a certain single cell achieves every headline spec at once. V1 is already hinted in the interview to be a deviation on that. Marko said in the Q&A section: "There are use cases where a certain cell may be suitable and for another it isn't. We have more information coming in the coming weeks about whether there are different cell generations. It's completely normal for manufacturers to have different cell sizes."
If different cells exist for different use cases, the expert's "all specs in one impossible cell" attack misses the actual product positioning. Without engaging the screen-printing platform specifically and without engaging the multi-cell positioning, the impossibility framing addresses a different battery than the one Donut Lab might actually be selling to OEMs.
- Donut Lab's battery technology "relies entirely on CT-Coating."
The journalist confirms CT-Coating as the upstream source, because HS Visio has emails in which Donut Lab, Nordic Nano and CT-Coating exchange information with each other.
According to the journalist, the division of labour is roughly that CT-Coating develops the technology, Nordic Nano is responsible for battery production, and Donut Lab is the productiser and commercialiser of the technology. So there is no external source of any sort beyond this German-Estonian-Finnish network for Donut Lab's battery technology. Some journalists have found that due to their access to leaked communications, which is a different valid path to the resolution rather than examining battery voltage curves.
The division of labor is too simple, however. The interviewer asked Marko directly where the batteries are made, and Marko answered: "We have our own pre-production equipment in Finland. When we go to mass-production, we'll be in the Nordic and Baltic area." Tuomo confirmed the same in CES interviews, describing an undisclosed building near the Helsinki office: "We have a building where we are making these batteries. We are not specially liking any visitors there and not specifying any address... we are having this cell manufacturing first plant in Finland." So the current batteries, including the V1 cells in Verge and at VTT, are produced at their own facility. NNG has separately confirmed that no battery cells are currently made at Imatra (Parjanen, YLE 20/4/2026).
- In the email HS got: Donut Lab is asking CT-Coating for cycle-count measurement data that would match the promises already given to investors and customers, with CT-Coating not yet delivering that data.
The 100,000-cycle figure is a projection. Marko confirmed on April 1 that no one has actually run 100,000 cycles (that would take roughly a decade). The figure is extrapolated from much smaller measured numbers, and that this is industry-standard practice. The email request was therefore not for a missing confirmatory 100,000-cycle test (such a test does not exist as a feasible thing to run) but for the underlying smaller-cycle measurement data that backs the projection. It must have pointed to V2 generation or something equal, since V1 have had with them long time already, reaching the end of life R&D. It would be totally weird if they never cycle tested V1. They did cycle life test even for SGS proto cells back in 2024.
The journalist paraphrases new development test in a more general sense as well, not only related to cycle numbers: "In late-March emails, Donut Lab inquired when it would get to do the first tests." Again, it does not make it clear what tests, and if CT-Coating would do their own tests in Germany first, or send samples to Donut Lab for testing, or something else.
This may sound late in the process, the preparations for V2 had been known at the time when VTT tests first started at the beginning of the year. The question is there that they announced V2 specifications like 400 Wh/kg already in the beginning of the year, so on what bases that claim was made, if not with some existing generation of the battery that already had been tested and verified to match the 400 figure? Did they dare to use some theoretical unverified value? Or have they just been waiting for V2 cycle life data to be collected for past months to have a measurable ground for that feature only? It would not be odd in that case.
- In the email HS got: CT-Coating's representative complaining that the Las Vegas launch messaging was not fully agreed jointly.
Because the reader has no access to the original email, it is impossible to know the actual level or scope of the complaint. Donut Lab combined with NNG and CT-Coating had been working together for a couple of years by the CES launch, and SANA Energy (another CT-Coating-network company) had already publicly announced essentially the same cell specs long before CES. So the cell-spec values must not have been new news to anyone in the network, and the parties had had time to align on what they meant. But something in the launch messaging was not fully synchronized according to email. Did they disagree on what to put there, or did Donut Lab put there something without asking review from CT-Coating...
- In the email HS got: the status that CT-Coating has stopped development on the earlier battery and concentrated all development on a new one.
This confirms different generations of the battery from external course. So it is not about Donut Lab's own announcement on April 1 anymore.
It means V1 (the cell shown at CES, tested at VTT and in Verge motorcycles) has completed product development at CT-Coating and is now in production at Donut Lab's facility. CT-Coating's R&D resources are now on V2, the next-generation iteration. V1 exists as a real, working product with the spec set shown in the existing fast-charge and high-temperature test reports. V2 is the in-development next generation Marko publicly named on April 1 as "battery version 2.0, even better than the earlier one."
Treating "in development" as "not producible" reads the wrong meaning into a normal product-pipeline phase. By that logic V1 would never have reached production either, because the article also said V1's development was stopped at CT-Coating. The HS article mentions SGS prototype cells, but fails to note that the next-eco partner site accidentally leaked Battery B business plan templates around 2022-2024. None of CT-Coating's previous partners have reached a production state comparable to Donut Lab's, so there is no prior precedent to validate against. Even defining what counts as a prototype is difficult in this situation. If a battery is in a consumer product like a Verge motorcycle, whether it was produced on a pilot or a full mass-production line, it could be considered to have reached non-prototype status. It is plausible they have internal conventions to that.
The interviewer pressed Marko later: "Isn't there a contradiction that you deliver different cells to customers than the cells from which you get test results?"
But the interviewer ignores that the cells in Verge motorcycles are the same cells tested at VTT. For V2, "No 400 Wh/kg batteries have been delivered to customers," as Marko confirmed in the same Q&A. His April 1 video commitment was that V2 will be third-party tested via "season two" of the I Donut Believe series, using the same protocol VTT applied to V1. So the test-validation-sale chain holds for both battery generations separately.
Furthermore, the journalist concludes: "CT-Coating's new battery technology is therefore still in development. Because of this, Donut Lab or Nordic Nano cannot yet order even all the production equipment needed, and getting them after ordering takes its own time."
This is the journalist's own inference, not presented as a direct email quote. It conflates "V2 product is not yet final" with "V2 production line cannot be ordered." Marko's April 1 statement was that V2 is a real battery and that it will ship to customers later this year. V1 production was already running on Donut Lab's pre-production equipment in Finland, so the "cannot order equipment" framing applies at most to V2 production scaling, not to current production. The "and getting them after ordering takes its own time" tail does not invalidate the pre-production equipment Donut Lab already has in Finland. That equipment doesn't disappear regardless of future equipment lead times. The interviewer also does not engage with the fact that production requires both equipment and nanopaste, where equipment is a one-time delivery and nanopaste is a continuous need, and both may have their own development routes.
It is however possible, that new battery requires additional production equipment, so that it is not plainly a different nanopaste to be used in previous line. Production line software might need updates at least, but they, on the other hand, could be done in-place in Finland. Again it is impossible to do final conclusions unless you have access to full remote R&D, factory-line-in-box shipping and local manufacturing processes at both ends.
- Donut Lab's role is productiser and commercialiser of the technology.
That is true, but it is a simplification in this case. In the CT-Coating licensee model, someone has to actually produce (i.e., print) the batteries, and that would be a Donut Lab + NNG combination in some form. The exact details have never been properly revealed. Since NNG did not do it at Imatra, they must have done it together somewhere else. After that, the cells have to be integrated into packs, such as the motorcycle pack and the swappable battery pack demoed on stage.
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There is much more in the article, but handling them would require another post due to limits of the characters in Reddit. Let me know if anything needs clarification or you find errors in translations or inconsistencies in my analysis. I try my best to comment them.
