Exclusive: Secretive startup Holyvolt raises at €182m valuation for batteries that can be printed on almost anything

Swedish energy startup Holyvolt has raised €12m at a €182m valuation, Impact Loop can exclusively reveal, just months after filing a patent for screen-printed solid-state batteries that the company claims can be applied to almost any surface.

Impact Loop first lifted the lid on the company – which operates a lab in Munich, Germany – in late 2024 when Holyvolt raised €9.4m despite still being in stealth mode.

Investors include Volvo, climate tech VC Course Corrected, and FAM, the investment vehicle of Sweden’s Wallenberg family, which appears to have since divested its stake in Holyvolt, according to the latest company filings.

The identities of the investors in the latest round remain unknown. Holyvolt’s CEO Mathias Ingvarsson, who is notoriously tight-lipped about the company’s operations, did not immediately respond to requests for comment.

Holyvolt has also remained characteristically secretive about its technology, which it says has origins in German research developed over 20 years. However, a recently published patent filing reveals the company’s tech in detail for the first time.

Batteries you can print

Filed in May 2025 and published in November, the patent details a screen-printed solid-state battery that's flexible, lightweight, and claims to eliminate lithium, cobalt, nickel, lead, cadmium, and all rare earth metals.

Screen printing – a manufacturing method where materials are pushed through a mesh screen layer by layer – is cheap and scalable, but applying it to solid-state batteries with particulate materials has never been attempted on a commercial scale.

Holyvolt uses nanoparticles between 10-100 nanometers for cathode and anode materials, which the patent claims improves adhesion and flexibility.

The patent lists 73 potential applications, from consumer electronics and EVs to heated wallpaper, solar-powered camping van sunblinds, illuminated fashion, and "armour with energy storage." It's a pitch for batteries that can be printed on nearly every surface imaginable.

While Holyvolt has brought in significant VC funding for its technology, it is already generating revenue as well.

In 2024, the company reported over €5m in net sales in its first year – unusual for a company still in R&D. The bulk of the proceeds came from the sale of machinery and equipment to an unnamed “industrial partner,” Ingvarsson told Impact Loop in one of the rare occasions we’ve been able to reach him.

While the patent remains just a patent, Holyvolt’s substantial revenues, funding, and partnerships suggests that it is, at the very least, testing its technology with third-party suppliers or manufacturers.

Connection with Donut Labs?

While the company has refused to name its partners, there has also been some speculation among Finnish technology enthusiasts that Holyvolt is connected to Donut Labs – the recently hyped Helsinki-based startup made waves at CES in Las Vegas in January with bold claims that it would soon release a motorcycle in partnership with Verge Motorcycles featuring the world’s first “production-ready” solid-state battery. The claims have already drawn scepticism from parts of the battery industry.

An active discussion on the Finnish tech discussion forum TechBBS, suggests that the solid-state batteries presented by Donut Lab are potentially supercapacitors developed by Nordic Nano, combining nanoprinting technology and nanomass developed at Holyvolt.

Donut Lab invested in Nordic Nano last year, and the company’s CEO Marko Lehtimäki sits its board. However, Lehtimäki denies it sources its batteries or IP from Nordic Nano.

Impact Loop could not immediately establish a connection betweenHolyvolt and Donut Labs or Nordic Nano, but we will investigate further and update this piece if required.