Assessing the current developments in the field of energy storage

Assessing the current developments in the field of energy storage

Data centre leaders are discovering innovative ways to enable greater efficiencies when it comes to energy, and the battery storage sector plays a big part. Jason Koffler, MD and Founder, Critical Power Solutions, explores the latest developments in battery storage technology and how hydrogen cells contribute to this, as well as why Sodium-ion could be the way forward.

Jason Koffler, MD and Founder, Critical Power Solutions

In modern society, the ubiquitous battery is more important than ever due to the push for sustainable forms of transportation and the desire for immediate power at the point of use. As more emphasis is placed on renewable energy sources, where output may often depend on weather conditions, there is a substantial need to store the electricity generated just moments before. This industry is nothing if not innovative, as the sheer scale of the challenge continually leads to major innovation. So, what are the latest developments in battery storage technology and how do hydrogen cells contribute to this?

The scale of the challenge

The International Energy Agency (IEA) estimates that energy storage requirements could increase by 50 times by 2040. There is a push to develop new storage options that can deal with this first but at a cost that would make them affordable on both the supply and demand side.

Innovation in response

It may come as little surprise to learn about the scale of innovation in this area. According to the IEA, more than 7,000 international patents were granted in 2018 in the realm of electricity storage, a sizeable increase over the 1,000 or so at the turn of the century. These patents indicate the push towards clean energy technologies in electric mobility and personal devices.

Areas of focus in the field of energy storage

Thermal management

In the search for efficient energy storage systems, thermal management is key. This allows batteries to provide power effectively and safely through effective management of heat. Battery manufacturers must ensure that these units are as effective at shedding heat to the environment as they are at reducing the generation of heat in the first place while improving performance.

With this in mind, expect an additional emphasis on liquid-cooled battery energy storage (versus air-cooled). This approach can help to manage internal temperatures while minimising degradation. Liquid cooling options use less energy, enabling high levels of performance and markedly increasing the battery’s longevity.

Power conversion systems

Expect developments in the field of power conversion systems – a primary piece of equipment connecting the battery to the grid and converting DC into AC. Electrical grid operators are exploring the capacity of battery electric storage systems to help them with deployment and ensure the stability of the grid. Dynamic regulation and dynamic moderation solutions will help to address stability issues throughout the network with the support of battery electric storage.

Hybrid storage solutions

Look for hybrid storage systems in the residential sector that can more effectively combine a photovoltaic roofing structure with the battery and inverter, creating a microgrid at home. These systems will become increasingly more cost-effective to install and operate and will certainly be attractive given the recent incredible rise in traditional energy cost. There will also be more focus on longer-duration storage systems that will help to improve grid utilisation and lower transmission costs while easing peak demand.

Developments in technology

Lithium-ion technology

Of course, Lithium-ion technology has dominated the sector up until this point. Still, there’s been increased focus on cathode chemistry in the hunt for better energy density and lower costs. Energy density is particularly important for electric vehicles, as manufacturers seek to manage cost versus performance.

Latest developments show an increase in focus on lithium nickel cobalt aluminium oxide, or NCA, with better durability, recyclability, power output and charging speed. This technology is likely to dominate electric vehicle battery production in the near term.

The Sodium-ion challenger

Sodium-ion battery systems could soon challenge Lithium-ion. By substituting lithium for sodium, which is far more abundant, other lower-cost materials could be used within the cathode, such as nickel and cobalt. While the technology may not be particularly new, lower prices may now drive the technology forward at an increased rate.

Sodium-ion could more easily find its way into the mainstream as it can use similar processes and technologies to those found within the Lithium-ion industry. Sodium-ion could benefit from existing economies of scale within the supply chain while capitalising on the relatively low cost of sodium as well.

However, engineers will still need to find a solution to the life cycle problem, as a Sodium-ion battery is not expected to last as long as a Lithium-ion alternative. This means it may be some time before Sodium-ion can meet the demands posed by the growing electric vehicle industry. However, Sodium-ion may nevertheless be a viable alternative in other less demanding sectors.

What about flow battery technology?

Other innovators are moving far away from the concept of Lithium-ion or Sodium-ion. Flow battery technology has been championed by NASA, among others, and would seem to have some promising potential. These batteries can be used to optimise the amount of energy stored and save money at the same time, due to the rate at which they store and release the energy. In addition, this battery system should be safer, stable and a lot more sustainable.

Redox-flow versus hybrid-flow

Flow batteries feature two different technologies. Redox flow batteries have electro-active materials dissolved in a liquid state electrolyte. Hybrid flow batteries have one active material within the cell, while the other is in the form of a liquid flowing from an external tank into the reaction cell. No flammable or explosive materials are involved and each component within the flow battery is recyclable.

Advantages of iron flow batteries

Compared to a Lithium-ion battery, expect the iron flow battery to last much longer without a charge and to have an extensive life cycle. These batteries could operate across a broad range of ambient temperature conditions without the need for air conditioning or heating. They may certainly be much cheaper when it comes to the overall cost of storage than Lithium-ion.

Zinc bromide flow batteries are more prominent than vanadium redox, as they currently provide the greatest energy density solution. Several major manufacturers intend to invest heavily in this technology as an eco-friendly and cost-effective alternative to Lithium-ion cells.

Exploring hydrogen cell tech

Meanwhile, hydrogen cell technology offers an energy-dense and clean power source, especially in transportation. However, this tech is still too expensive and has limited support infrastructure. Hydrogen power may represent a more lightweight solution than battery cells, but it has a way to go before the technology is sufficiently developed to address those ever-present range and charging concerns.

Challenges with hydrogen

Furthermore, there is still a challenge associated with hydrogen production, which requires a significant amount of energy, and there are many inefficiencies in the production process compared to the traditional battery. As significant strides are being made in the world of battery and fast charging technology, this could quickly overrun the potential for hydrogen fuel cells.

The hunt for greater efficiency

The battery storage sector continues to push forward at pace in the hunt for greater efficiency, but with ever-present political and public relations pressure. While Lithium-ion remains the dominant technology, there will always be a desire to reduce cobalt use. After all, in its natural form, this metal can only be found in certain parts of the world and is inherently toxic in nature. Some countries also use questionable mining techniques that may infringe upon human rights, and with hydrogen facing its own challenges related to production efficiencies, it seems that Sodium-ion could be the way forward.

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