‘World-changing’ solar cells could mean the death of batteries

EIn just six seconds, in a factory on the northern edge of Stockholm, a top-secret printer churns out sheets worth thousands of euros each. Each one contains 108 miniature solar cells that will soon find their way into everyday gadgets – from keyboards to headphones – that will fundamentally change the way we interact with technology. According to their creator, they will even force us to reconsider our relationship to light.

Sweden may seem like an unlikely place for a solar revolution, but the lack of light during the winter months was one of the reasons why Exeger co-founder Giovanni Fili looked beyond the sun as the only source of energy for a photovoltaic cell. His company’s revolutionary technology can harvest electricity from almost any light source, from direct sunlight to candlelight. It can even generate a charge from moonlight, though it would take some time for it to be of much use.

“Like algae at the bottom of the ocean where it’s almost pitch black, we can use very few photons efficiently,” says Fili The Independent. The T-shirt he wears describes his company’s technology as “world-changing,” capable of simultaneously addressing the global need for energy and some of our planet’s greatest environmental challenges.

The Powerfoyle solar cell is durable enough to fit into bike helmets, while also versatile enough to mimic leather and brushed steel to fit into bags and speakers
The Powerfoyle solar cell is durable enough to fit into bike helmets, while also versatile enough to mimic leather and brushed steel to fit into bags and speakers (The Independent)

Indoor solar panels have been around for decades. Solar-powered calculators were first introduced in the 1970s, but the limitations of the amorphous silicon cells they rely on mean they are too low-powered, too fragile and too rigid to be integrated into other products.

The most recent innovation stems from the 1988 discovery of dye-sensitized solar cells (DSSCs). Two scientists at UC Berkeley in California invented a low-cost, high-efficiency cell that was both semi-flexible and semi-transparent, paving the way for commercial development of the technology.

Just over 20 years later, Fili and Exeger’s other co-founder, Henrik Lindström, came up with a new electrode material that offers 1,000 times better conductivity. The breakthrough was the basis of their Powerfoyle cells, which are now produced on a commercial scale.

Exeger’s Powerfoyle solar cells offer a radical departure from traditional glass-covered panels, eliminating the need for the silver lines you see on them that act as conductors. They are also not sensitive to partial shading, which drastically reduces the efficiency of photovoltaic panels.

The patented leather-like material can even be transformed into almost any material to allow seamless integration into a wide variety of products while remaining waterproof, dustproof and shockproof.

“It works in all light conditions, is more durable than any other solar cell in the world, is easy to manufacture and can imitate any surface – leather, carbon fiber, wood, brushed steel. It’s also beautiful,” says Fili. “So we can integrate into products that are already selling billions of units a year.”

Exeger’s facility in Stockholm has the capacity to produce 2.5 million square meters of solar cells each year, making it the largest factory of its kind in Europe. Speaking at the 2021 factory opening, Fili predicted that Exeger’s technology would “touch the lives of one billion people by 2030.”

Exeger says its Powerfoyle solar cell is the most durable in the world
Exeger says its Powerfoyle solar cell is the most durable in the world (Exeger)

Powerfoyle solar cells have already found their way into seven products on the shelves – including headphones, wireless speakers and a cycling helmet – while six more have been announced. Among the buyers are Adidas, Phillips and 3M, while they are also rumored to be in talks with LogiTech and Apple.

A future without batteries

Exeger is one of several startups leading the commercialization of indoor solar panels, with the promise of clean, endless energy attracting researchers and entrepreneurs alike.

The American company Ambient Photonics was attracted to the space by the “magical” potential of the smart home, as well as the hope that it will be possible to eliminate the need for disposable batteries.

“The extent to which smart electronics can be applied is limited by battery life and the use of traditional batteries, which require continuous charging, stagnate product design and have negative environmental consequences,” Bates Marshall, co-founder and CEO of Ambient Photonics, said The Independent.

Billions of disposable batteries are thrown away every year
Billions of disposable batteries are thrown away every year (Getty Images)

According to figures, TV remotes alone are responsible for 3.1 billion disposable batteries thrown away each year estimates from Samsung. The Korean electronics giant has made switching from alkaline batteries to photovoltaics a priority to meet sustainability targets, claiming it could cut its greenhouse gas emissions by around 6,000 tonnes a year.

“Each advance in the power density of our product brings us closer to a future where the need for disposable batteries is greatly reduced, if not completely eliminated,” says Marshall.

Ambient Photonics’ DSSCs have so far been integrated into remote controls, although limitations with the amount of heat and light they can be exposed to mean the technology is currently limited to indoor applications.

The versatility and durability of Exerger’s Powerfoyle means the only limitations are power-intensive devices like laptops and smartphones – although these could provide a significant 50 to 100 percent increase in battery life. Exeger is also researching a solar-powered tablet case that could provide enough power for infrequent users to never need to charge the battery.

“Our grandchildren will laugh at us for having cables,” says Fili.

Product prototypes incorporating Exeger's Powerfoyle solar cells include tablets, bags and even curtains
Product prototypes incorporating Exeger’s Powerfoyle solar cells include tablets, bags and even curtains (Exeger)

One trend that Fili has noticed is that users of Powerfoyle products have become much more aware of their surroundings and the presence of light in their lives. “We make people aware of light,” he says, “because light is power.”

Fili is driven by the belief that Powerfoyle is era-defining technology. Exeger is the first to commercialize the technology on this scale, although it’s still relatively new given that Fili sees everyone on the planet as a potential user. Others seem convinced of his claims, with Forbes comparing him to the likes of Jeff Bezos, Bill Gates and Elon Musk.

The technology behind Exeger’s solar cells, as well as the printers that produce them, is a closely guarded secret. Even the purpose of the thousands of Powerfoyles currently being printed every minute at the Stockholm factory is not yet known to the public. (Their elongated shape strongly suggests that they will be used in a product that most of us use every day – the one on which this article is being written.)

“This is really, really huge,” says Fili. “We have just secured a contract with the world’s largest supplier of keyboards and mice and have already partnered with some of the biggest companies and brands on the planet. This technology is going to take over the world.”

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