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Hydride Battery Technology Designed for >20 Years of Energy Storage Life

January 22, 2019 by Paul Shepard

Swedish industrial battery manufacturer, Nilar, has developed a method for multiplying the life of its Nilar Hydride® batteries (NiMH). The company announced this advancement in operating life after years of research at its Swedish and US R&D centers, and in close collaboration with leading researchers from Stockholm University.

The limited lifetime of batteries is an issue for users. Thanks to the new patented process, the Nilar Hydride®batteries will be able to handle considerably more charging cycles - and thus store and deliver far more energy throughout their lifetime - than other industrial battery technologies. This equates to a significantly reduced cost per kWh, which provides the lowest total cost of battery energy storage available on the global market. The robust, safe and environmentally-friendly characteristics of the battery are unaffected by this breakthrough.

"With this technology breakthrough we have found a way to re-condition a battery," says Professor Dag Noréus from Stockholm University. "Typically, in Hydride batteries, the metal hydride in one of the electrodes slowly consumes the water-based electrolyte, which connects the plus and minus poles.

"However, the unique design of Nilar batteries makes it possible to counteract this aging process of the metal hydride. Adding oxygen causes new water-based electrolyte to form in the battery. This replaces the lost electrolyte and restores the internal electrode balance. With the right balance of oxygen and hydrogen, Nilar batteries can reach a lifetime that surpasses other corresponding battery technologies," Professor Noréus added.

Nilar EC Battery pack

The Nilar EC (Energy Compact) Battery pack is a battery designed to meet the time shifting and peak shaving needs of today and tomorrow. Combined with our advanced bi-polar NiMH battery technology the Nilar EC Battery pack is a safer, greener, more reliable and cost-efficient energy storage solution. The Nilar EC Battery packs have a capacity of 10Ah and are available in configurations of 96V, 108V, 120V and 144V.

Benefits in brief:

  • Wide operating temperature range from -20°C to +50°C
  • Designed for a service life of 20+ years
  • Maintenance free thanks to sealed design
  • Environmentally friendly
  • Recyclable from cradle to cradle

Speaking about the breakthrough Nilar CEO, Marcus Wigren says, "A long service life is extremely important for our customers. Being able to offer the lowest cost energy storage solution to commercial real estate and private households gives us a huge competitive advantage. Research, development and innovation have always been an important part of our business and it is very satisfying to see our investments continue to give such good results. Protecting the environment is also one of our key drivers; being able to hugely extend the life of a battery is a big step towards a fossil-free and sustainable society."

Michael Obermayer, Nilar's Chairman of the Board, adds: "The European Union has set itself the goal of regaining leadership in the strategically important battery industry, and is committing significant supporting funds. With this fundamental innovation, we have laid the foundation for a new Swedish research-based battery industry. I believe Nilar is now a key player in this new European strategy and we will continue our fast move towards the company's IPO."

Nilar plans to launch the new patented technology for the Nilar Hydride®batteries later this year.

Background on the research at Stockholm University

Most rechargeable batteries are based on either lead, nickel-cadmium (NiCd) or various combinations with lithium. Batteries based on nickel-metal hydride (NiMH) with an aqueous electrolyte are both eco-friendly and safe. The NiMH battery is developed from the nickel-hydrogen battery (NiH2). It has long been known that (NiH2) batteries have a superior lifespan compared to other battery types. This is why they are (for example) used in satellites in orbit in space, where the batteries must function for decades without servicing. The Hubble space telescope is one example, but NiH2batteries are also spinning around our neighboring planets.

However, these structures of the batteries are impractically large, because the hydrogen is stored in gas tanks. NiMH batteries can be made much more compact, because the hydrogen is stored in a metal alloy/metal hydride with a hydrogen density equivalent to that of liquid hydrogen. Researchers at Stockholm University has now developed a technique by which to achieve the same long lifespan for NiMH batteries as in the large NiH2batteries.

The inspiration for the new technology came from a new NiMH battery manufactured by Nilar AB in Gävle.

In a NiMH battery, hydrogen is bound in the metal alloy. This solution is effective, but the battery ages because it dries out as the alloy slowly corrodes and consumes its water-based electrolyte. The corrosion also interferes with the internal balance between the electrodes in the battery.

The breakthrough came when the research group discovered that they could counteract the aging process almost completely by adding oxygen, which restores the lost electrode equilibrium and replaces the lost electrolyte. This can be easily done in Nilar's battery construction, because all cells share the same gas space. With the right balance of oxygen and hydrogen, a lifespan is achieved which exceeds all of today's common battery types.

"The electrification of society, not least of all future electric cars, places new demands on distribution networks. This battery type is very well suited to evening out the load on the power grid at all levels over a long period of time, something which is a prerequisite for a fossil-free society in which intermittent solar and wind power will be connected to the network," says Professor Dag Noréus of Stockholm University, who has extensive experience with NiMH development.

"New battery technology is a major step along the way. Right now Sweden is a world leader in the segment of rechargeable NiMH batteries," says Dr. Yang Shen, whose thesis Development of metal hydride surface structures for high power NiMH batteries -  extended cycle-life and lead to more effective recycling methods was presented on December 10 of this year and has been a central element of the work.