elevator inverter 15kw A battery that doesn’t blow up, doesn’t use scarce rare earth metals, and can power your house for 20 years — is it possible? VoltStorage, a Munich-based startup, which just received €6m in VC funding, thinks it has the answer.
It is about the size of a small fridge and uses vanadium redox-flow technology to store energy, rather than the lithium-ion batteries that are used for powering laptops and electric cars. NASA is in fact exploring the same technology for future Mars missions, due to its long life, safety and affordability.
VoltStorage, however, is concentrating on applications closer to home, namely, the market for home energy storage, particularly for people wanting to store solar energy.
“Millions of houses now have solar panels on the roof, so it makes sense to have a battery that can really make use of the energy these generate,” says Michael Peither, cofounder and chief technology officer of VoltStorage.
VoltStorage, founded in 2016, is among a new wave of startups focused on energy storage, alongside Switzerland’s Energy Vault, a gravity and kinetic energy-based storage startup, which raised $110m from SoftBank last year.
The idea for home energy storage has been recently popularised by Tesla’s Powerwall batteries, but these are based on lithium-ion technology, which has a more limited lifecycle. Tesla’s Powerwall generally comes with a 10-year warranty, while VoltStorage’s redox-flow batteries are geared towards 20 years.
Peither began building his first redox-flow batteries in his parents’ basement, because his father wanted to find ways to store the energy from the family’s solar panels. At the time Peither was working electric cars for BMW, and had seen first-hand the teething problems with lithium-ion batteries.
“They were very expensive, and they do blow up,” he says. “I thought, there must be a better way to do this.”
The disadvantage of vanadium redox-flow batteries is that they are very heavy, and thus have tended to be used for very big energy storage projects. VoltStorage has, however, found a way to make the design relatively compact, and easy to install in the corner of the average home. VoltStorage has also developed an automated manufacturing process for the batteries — most other vanadium redox-flow batteries tend to be assembled manually as one-off projects.
This means the price for a battery is around €7,000, in the same ballpark as a Tesla Powerwall