Storing solar or wind energy indefinitely in a safe battery, without hazardous substances, which is one hundred percent recyclable. It is possible in the Swiss salt battery marketed by the Dutch company Fortona. During its presentation at solar energy trade show Solar Solutions International, the battery drew a lot of attention.
"This is the only salt battery at the fair. There is so much interest in it that my throat hurts. So many times I have to tell about it," says Parsa Tashacori of the Hanzestrohm Group, which includes Fortona. For three days the stall was extremely busy and to top it off, the salt battery was named the winner of the Smart Storage Innovation Award. At this year's for solar energy, most of the interest is not only in solar panels and related equipment, but also in energy storage. And especially new types of storage that can replace traditional lithium-ion batteries.
Those batteries are unsustainable, unsafe and environmentally polluting. poisons the environment and takes place under poor working conditions, often in countries with corrupt regimes. In addition, lithium-ion batteries still sometimes catch fire and are in electric cars. "You don't want those in your home or business. Moreover, other batteries are often in short supply of raw materials and materials," Tashacori said.
The salt battery or SMC battery (Sodium Metal Chloride) is then a durable, safe and reliable alternative. It has been further developed in recent years by Swiss manufacturer FZSoNick. It consists of 32 percent table salt, 22 percent nickel, 22 percent iron and 20 percent ceramic. Relatively inexpensive, non-hazardous substances that are easily recyclable and of which there is plenty of supply available in the world, although are for nickel in Indonesia. It is also called Sodium Nickel (SoNick) or ZEBRA battery.
Heating for energy storage
How energy storage in salt works? By adding beta aluminum as a fast conductor to the salt, the mixture of nickel and salt becomes liquid at 150 degrees Celsius. At a temperature of about 250 degrees, the battery cell in which this occurs can be used for energy storage. Nickel forms the positive electrode and the heated salt forms the negative electrode. So the battery does need to be warmed up before use, but it does that itself through an internal and energy-efficient control system.
Unlike lead and lithium batteries, the salt battery cannot burn or explode because it contains no flammable material. The efficiency is as high as lithium-ion batteries, but the salt battery is lighter. The battery can handle 4,500 cycles and can simply be turned off in the winter months, for example, when there is little solar power. Wind or solar energy can be stored in it for as long as needed. Another advantage is that it is modular and scalable, can store from 3.6 to 10 kilowatt hours of power, and more as needed.
No connection to grid
The battery was late last year and has been available on the market since this year. Fortona is primarily targeting SME companies and housing associations. The battery is a solution for companies or residential areas that cannot get a heavier connection to the grid and therefore want to store their own wind or solar energy. "We get a lot of requests, says Tashacori. "When the net-metering scheme is phased out in a few years, it will also become attractive for homeowners with solar panels." Those earn more now by feeding solar power back to the grid, which is deducted from their energy bills, but after 2030 they won't. Then batteries will become attractive again.
Other salt batteries
Fortona and FZSoNick are not the only companies that have developed salt batteries. Within the , Ten's sea salt battery is also supported and subsidized. This battery was developed back in 2007 by inventor Dr. Marnix ten Kortenaar for the storage of wind-solar energy. The result of this project was a clean, low-cost demonstration battery of up to 24 kilowatt hours that can be discharged to the grid or to an electric car. The battery can be charged by solar panels, including by homeowners.
Heating millions of homes
Another salt battery was developed by Olaf Adan, professor at TU Eindhoven and scientist at TNO. Its main purpose is to heat houses so that they can get rid of gas. The principle is simple: by adding water vapor to salt crystals, they expand and heat is released. Then, to recharge the system, those salt crystals are separated from the water and regain their original size.
The heat battery can be charged with both heat and electricity, that is, with waste heat or solar panels. Because no energy is lost, the battery is much more sustainable than, say, an electric home battery. The technology could heat . To bring the battery to the market, spin-off was founded, which has been rated within the Eurostars project as Europe's best in 2022. In Eindhoven, Cellcius will install a prototype in a number of homes. Also in some homes in southern France and Poland. This is partly paid for by the European Commission.