Stealth founder sits down for first major interview: 'We don't need to brag about what we're working on'

What finally drew the mysterious energy startup Holyvolt into the open was its acquisition of American battery company Wildcat Discovery Technologies, announced last week.

For years, Holyvolt has kept an extraordinarily low profile. Founded in 2022, the company spent a long stretch building almost entirely in silence – no press releases, no public presence, not even a website. Yet clues kept emerging: a technology concept rooted in screen printing and thin-film layers for manufacturing battery components, and a laboratory in Munich.

Along the way, the company has raised substantial sums – with company filings showing both Volvo and the Wallenberg family's investment arm FAM are among its backers – and completed several funding rounds that point to a rapidly scaling operation.

Eyebrows were raised further when Holyvolt posted unusually strong early revenues, with a significant portion reportedly tied to machinery, equipment sales, and an unnamed industrial partner. The company's 2024 turnover came in at roughly €9.5 million, with net revenue of around €5.3 million and an EBITDA of approximately €560,000. Asked about 2025 figures, the company says it cannot comment while an audit is ongoing.

The 'full story'

When we sit down with CEO Mathias Ingvarsson – who had promised "the full story" but arrives with a colleague to make sure he doesn't say too much – we start with the basics: what exactly Holyvolt is trying to do with battery manufacturing, one of several applications the company has filed patents for.

"If you want to put it simply, it's about the electrodes – the cathode and the anode," he says.

The goal isn't to reinvent the battery from scratch, but to fundamentally change how its core layers are made. The underlying technology itself is 600 years old, says Ingvarsson. But makes Holyvolt's tech compelling isn't its novelty, but the economics.

"Our core thesis is that it's highly economically disruptive. It's cheap," he says, before catching himself: "When you say cheap, people assume poor quality. But something can be excellent and cheap at the same time."

He then launches into Holyvolt's pitch for why this could shake up an industry accustomed to billion-pound factory investments and complex manufacturing processes.

"You can iterate far more easily and at a fraction of the cost," he says.

Screen printing is one half of the idea. The other is a water-based formulation – a kind of paste – that makes up the anode material in the battery. Together, Holyvolt believes it can produce batteries faster and more cheaply than existing methods. But the ambition goes beyond pure efficiency.

"Our founding idea is to eliminate nickel and cobalt – both for geopolitical reasons and for sustainability," says Ingvarsson.

From lab to pilot – navigating the valley of death

Ingvarsson is at pains throughout the conversation not to oversell what works in the lab. Humility, he says, is everything.

Holyvolt's secrecy, he admits, has been partly deliberate.

"We'd rather develop something before we stand on the barricades and start shouting. The people who needed to know – customers and investors – have always had a very clear view of what we're doing," he says.

The company is now at what he calls a "demonstration stage," having shown that the technology works in practice.

"There are so many steps along the way. First it's an idea, then it's the lab. Then you have to get to pilot scale – and that's like night and day. And then from pilot to what's known as a gigafactory – that's another valley of death entirely," he says, referring to the phase where many promising startups hit unforeseen obstacles or collapse altogether.

To manage that risk as they push toward the pilot phase, Holyvolt is opting for partnerships – like the Wildcat deal – rather than trying to build everything in-house.

"We have the luxury of deciding whether we're the ones who should scale. I think some companies have lost their way trying to do everything themselves," says Ingvarsson.

So you'd rather license or sell the technology to others?

"We see ourselves much more as a… not a supplier exactly, but more of a facilitator for scaling," he says.

Setting the record straight on the rumours

When a company stays quiet for long enough, others fill in the gaps.

On internet forums, users have linked Holyvolt to Donut Labs, a hyped Finnish startup that made headlines after presenting what it claims is a solid-state battery – a next-generation battery type with significantly higher energy density.

Ingvarsson dismisses any connection. "There is none whatsoever," he says.

Another subject of speculation has been a joint venture called Holyvault – formed between Holyvolt and a German company – which Ingvarsson now reveals has been wound down.

"It was a test we ran for about six months. We learnt a lot from it, but we decided to move forward with the setup we have today" – meaning the Wildcat partnership.

An unlikely road to the battery industry

Then there's the small matter of how Ingvarsson ended up here at all. Without his rather eclectic career history, he says, he'd never have stumbled onto the idea behind Holyvolt.

He was previously European CEO of Tempur, the mattress company, which he left after it was acquired by American investors. He is also the man behind Frigo – a underwear brand featuring a dedicated anatomical pouch – which became a US venture backed by, among others, rapper 50 Cent.

That chapter taught him what brutal competition really looks like. "It was a tricky industry, so we turned it into a licensing play," he says.

After that came ski goggles.

"Right in the middle of COVID. That's where I learnt how brutal it is when things simply don't work," he says.

But the ski world left him with something crucial. It was there that the seed of Holyvolt was planted. Ingvarsson keeps the origin story short: "I wanted to find a way to generate heat inside ski gloves."

To the future

He describes using his own ignorance of battery technology as a trigger – a reason to question assumptions, run experiments, and bring in genuine experts.

"It's an incredible asset, as long as I can hold onto the humility of knowing I don't have all the answers – while surrounding myself with people who do," he says.

Occasionally, he admits, this leads to some fairly absurd moments. "Sometimes I come out with things that are just laughable," he says.

But Holyvolt is no joke. And however secretive and hard to pin down it all appears, it now consumes every hour of Ingvarsson's working life – split between the company's Stockholm office and its labs in Munich and San Diego.

"Everyone wants to be an entrepreneur in the media. But the reality is hell: 25 problems an hour," he says, laughing.