The goal is to boost the renewable energy boom by bringing out a quick-response and, more importantly, very cheap form of storage. Our interview follows.

Everyone is trying to lower the cost of batteries. What sets your approach apart?

Manufacturers generally choose a technology for the results it delivers, then work on bringing down the costs. Very often, though, a large part of the price simply stems from the raw materials used, i.e. metals and rare earths, which are also subject to the vagaries of availability and geopolitical risks. Having worked for 15 years in the automotive industry, and more specifically in areas concerning fuel cells and hydrogen, I was very familiar with these issues. So I started out, on my own, to search the scientific literature for the cheapest materials that could be used in a flow battery. And bingo! The answer was hydrogen bromide.

I’m sure it’s not as simple as all that!

You’re right. The basic principle had been known for over 150 years, but it was difficult, if not impossible, to use it for industrial purposes. More to the point, it was prohibitively expensive without the current technologies. The system involves handling a gas and a liquid at the same time: hydrogen and bromine, which are both highly reactive.  This is a good thing for the battery’s reactivity, but calls for solid engineering to address the safety issues. What’s more, the system as a whole remains quite complex. We did a lot of work therefore on simplifying the subsystems. Today, after operating for a year as a lab model, there haven’t been any incidents!

What are the next steps?

We’re going to build our first full-scale prototype this year: a 50kW module. Because our’s is a modular battery, all we have to do is add “cells” (editor’s note: the size of a car engine) till we reach the desired power (in W), and adjust the size of the tanks (editor’s note: which are underground, and variable in size), depending on the desired capacity (in Wh). This design gives us two decisive competitive advantages: we can industrialise our basic building block to the maximum and, more importantly, power and capacity are completely decoupled, which opens up a huge market for us. If we factor in the low material costs, we are offering a battery that is five times cheaper than its competitors.

So what applications are you aiming for? And when do you plan to go to market?

Our business purpose is actually to support the development of renewables by lowering the cost of storage, which is still the missing link in this sector. We have two targets in mind: customers that produce renewable energy for their own use, such as businesses, farms, shopping centres, privately-owned housing blocks, etc., and producers of renewable energy for sale, such as solar farms and wind farms. We are planning to launch the product on the market in 2018.

What will your business model be?

We will make the first 1,000 units ourselves so that the industrial engineering aspects are totally under control. But the potential market is so huge that we will licence the technology after that, with an effective tech support team.

How are you going to finance the transition to an industrial scale?

Our original investors (KIC InnoEnergy and Enfuro Ventures) are already following us: in late 2015, we secured the financing necessary to build the production plant and market the first batteries. This means the whole team can stay focused on developing the technical and commercial aspects. Here again, KIC InnoEnergy – without whom I would never have started up the business in 2014 – has been extremely helpful, mainly through its “KIC InnoEnergy students” programme, which introduced us to top-flight employees, completely in the start-up spirit. In short, KIC InnoEnergy gave me the support I needed to become an entrepreneur, and is now coaching me to become the head of the company.

The Elestor technology in brief:

(from the Elestor website)

The heart of a Hydrogen Bromide Flow Battery is the cell stack. This cell stack is on one side connected to an electrolyte fluid circuit (a water-based solution of bromine and hydrogen bromide, Br2/HBr), and on the other side to a Hydrogen (H2) gas circuit. Both the Br2/HBr and H2 circulate through their side of the cell stack, each in a closed loop. In each cell, the Br2/HBr and H2 circuits are separated by a proton-conductive membrane.

While charging, HBr is converted into Br2 and H2. The pressure in the H2 tank rises.

While discharging, H2 is consumed, the pressure in the H2 tank decreases, and electrical energy is released. During this process, Br2 is converted again into HBr.

And so on….

The advantages of the Elestor battery:

• 5 times cheaper than rival technologies
• Modularly scalable
• No self-discharge
• Short response time
• Low maintenance