Donut Lab’s miraculous solid state battery, promising energy density, charging and durability numbers unseen by the industry, has been subject to a criminal complaint in Finland from an insider who says it doesn’t live up to the public promises Donut Lab has made. But the company says that the insider didn’t work on the battery project, and denies any fraudulent behavior. Solid state batteries have long been promised as the next evolution of battery technology, using a solid electrolyte for theoretically much higher energy density. Despite these many promises over more than a decade, none have yet turned out to be manufacturable at scale and to offer better overall performance than current liquid/gel electrolyte batteries. But early this year, Finnish company Donut Lab shocked the industry with claims of a 400Wh/kg, 100k cycle life, 5-minute-charging solid state battery that it claimed was ready for production in Q1. Advertisement - scroll for more content Since then, Donut Lab has engaged in independent testing which validates some of its claims, but has left out important details, like energy density and durability. Since these are major parts of Donut Lab’s claims, their exclusion from testing results is suspicious. Further, Donut Lab’s claim of manufacturability in Q1 in 2026 has obviously not been validated, given that we are now in Q2 and the battery is yet to start being manufactured. Today, another potential bombshell has dropped: Lauri Peltola, the former Chief Commercial Officer of Nordic Nano, Donut Lab’s manufacturing partner for its battery project, has reportedly filed a criminal complaint against Donut Lab, accusing it of misleading the public with its claims, specifically on energy density, durability and production capacity. The complaint was reported today in Finnish by Helsingen Sanomat, the largest newspaper in Finland. Beyond the complaint, Helsingen Sanomat says that it saw communications stating that the battery provided for independent testing is an old generation that Donut and its partners gave up on development of, and that the new generation is in early development and not ready for mass production. Donut Lab and Nordic Nano responded to the complaint and issued a public statement, available both in Finnish and in English, claiming that they have not seen the full complaint and that Peltola would not have had the appropriate knowledge to make the complaint. Here is the response in full: Donut Lab and Nordic Nano Group have today been informed that an employee of Nordic Nano has filed a criminal complaint against Donut Lab. The companies do not know the exact nature of the complaint. In addition to the complaint, the individual has contacted media representatives and provided confidential company information to the press. Furthermore, the individual has made claims concerning Donut Lab, despite not having the necessary knowledge of battery technology or the overall picture of the development work. The individual is not a shareholder of Nordic Nano Group, nor are they involved in the working group developing Donut Lab’s battery. Nordic Nano Group does not share these views of a single individual. Donut Lab takes the allegations seriously, denies having committed any crime or misleading investors. Donut Lab and Nordic Nano Group are working closely together on the development of battery technology, and both companies strongly stand behind the previously announced information regarding battery properties and production. Donut Lab is currently conducting tests measuring battery properties with a third party, and more research results will be published during the spring. Regarding the increase in production capacity, the company has publicly stated that the goal is to reach one gigawatt this year. Donut Lab and Nordic Nano Group are currently investigating the matter together with the legal advisors of both companies. The companies naturally view such matters with extreme seriousness. Any unsubstantiated reports that aim to negatively influence the companies’ business operations and brand are handled with the same rigor. Marko Lehtimäki,CEO, Donut Lab Esa Parjanen,CEO, Nordic Nano Group Donut Lab and Nordic Nano say that they stand by their claims, and plan to have a gigawatt worth of production capacity this year (even this seems slightly questionable… cells should be measured in gigawatt-hours, not gigawatts), and that more independent testing will be released in the coming months. Electrek’s Take I’ve been in and around the EV industry for almost two decades now, and over the course of my time here, I’ve heard many claims about miracle solid state batteries being just around the corner. Most of them I ignore (or think that they’re intentional statements to delay people’s EV-buying purchases by making them think a breakthrough is just around the corner, as Toyota’s many solid state announcements for the last ~15 years have been). And battery research stories are common, and we rarely cover them, because every week there is some new breakthrough in a lab somewhere, showing that a battery has achieved a number never seen before in some aspect of battery performance. But to make a real battery and put it in a real vehicle, you need to have a good balance of every aspect of battery performance. Energy density is no good if your cells are power limited, because then you just need a huge amount of cells for the requisite power delivery, which means your battery is heavy after all. Power delivery is no good if you don’t have thermal performance, because then the pack gets throttled when it overheats. Charging speed needs to be balanced with durability. And so on and so forth. That’s why Donut Lab’s claims were so big, because they included several aspects of battery performance, and claimed to be right on the verge of manufacturability. Battery lab results are all well and good, but if they can’t be manufactured with current technology, then comparing them against current mass-produced batteries is meaningless. This is also why Donut Lab’s claims were met with skepticism, because for as many times as new batteries are promised that beat current batteries in one aspect of performance, one that beats everything in every aspect of performance is even more questionable. I too remain skeptical of Donut’s claims, but I’ve also seen plenty of disgruntled former employees lob accusations that were not necessarily fully true. So I’m not ready to conclude that there’s any malice here, but I’ll remain unconvinced that these solid state batteries are going to be available with anywhere near the promised numbers anytime soon. Instead, what I think is most likely to happen is that the state of the art of the industry will continue progressing at a rate of about 5%-10% per year in terms of overall battery performance (whether that be improvements in price, energy density, or what-have-you), as it has for decades now, and that new technologies will start off unrefined and gradually get better as battery manufacturing and research scale. I’d be surprised if any big step change happens. Charge your electric vehicle at home using rooftop solar panels. Find a reliable and competitively priced solar installer near you on EnergySage, for free. They have pre-vetted installers competing for your business, ensuring high-quality solutions and 20-30% savings. It’s free, with no sales calls until you choose an installer. Compare personalized solar quotes online and receive guidance from unbiased Energy Advisers. Get started here. – ad* Stay up to date with the latest content by subscribing to Electrek on Google News. 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