Unless you have been living under the a rock, you will probably be aware that battery storage is a constantly growing sector that has mining companies involved with the key commodities feeling all hot and bothered.

The growth is fuelled by increased demand for batteries in electric vehicles (EV) and stationary storage uses.

In its Global EV Outlook 2020, the International Energy Agency noted that in the Stated Policies Scenario, which incorporates existing government policies, the global EV battery capacity will increase from about 170 gigawatt hours (GWh) per year to 1.5 terawatt hours (TWh) per year in 2030.

This increases to 3TWh under the Sustainable Development Scenario that is fully compatible with the Paris Agreement, which seeks to keep the increase in global average temperature to well below 2 degrees Celsius.

Stationary uses are also forecast to grow with IDTechEx estimating a 38 per cent compound annual growth rate between 2021 and 2031 to a cumulative installed energy capacity of more than 1TWh.

This is due to the need to adopt energy storage systems to ensure that consumers have constant electricity available as renewable energy forms a larger part of the energy mix.

Lithium battery storage technology

No discussion about battery storage can avoid going into the different types of batteries that are currently in use and under development.

Lithium cobalt oxide (LCO) batteries – also the original lithium-ion chemistry – have a cobalt oxide cathode and a graphite carbon anode, giving it a high specific energy that makes it popular for mobile phones, laptops and digital cameras.

However, this chemistry has a relatively short life span (hence why your phone battery always seems to lose capacity so quickly), low thermal stability and limited load capability or specific power.

Meanwhile, lithium manganese oxide (LMO) offers high thermal stability, enhanced safety, fast charging and discharge though both cycle and calendar life are limited.

While its capacity is about a third less than lithium cobalt oxide, it often blended with lithium nickel manganese cobalt oxide (NMC) to improve specific energy and prolong the lifespan.

This combination is often used for electric vehicles with the former providing the initial boost used during acceleration while the latter is responsible for long driving range.

NMC itself is favoured for power tools, e-bikes and other electric powertrains though its exact properties can vary depending on the mix of nickel and manganese used.

Its popularity in battery storage use is increasing thanks to its balance of lower cost and good performance.

Lithium iron phosphate (LFP) offers high current rating, long cycle life, good thermal stability and enhanced safety.

However, it has lower specific energy compared to LCO along with higher self discharge compared to other lithium batteries.

Other lithium-based chemistries include lithium nickel cobalt aluminium oxide and lithium titanate along with solid state lithium-ion and lithium sulphur.

Vanadium, sodium and all the rest

Lithium-based batteries are not the only game in town.

Vanadium redox flow batteries (VRFB) have been available for some time now and are generally considered to be safer, more scalable and longer lasting than their lithium counterparts.

However, the need for electrolyte storage tanks means they are bulky and have a poor energy-to-volume ratio, making them suitable only for stationary applications.

VRFBs have already seen use in large-scale, grid battery storage systems.

Zinc-air fuel cells use zinc and oxygen to store energy and can be manufactured without rare or costly materials while sodium-sulphur batteries have already seen some use in large-scale applications globally.

Sodium-sulphur batteries have longer lifespans than lithium-ion batteries though there are risks involved with handling both sodium (infamous for its reaction with water) and sulphur.

Flouride has also been touted as another alternative to lithium and has the potential to have eight times the life. However, it is only recently that a liquid electrolyte has been developed that is usable at room temperatures.

Australian battery plays

There are a number of Australian companies involved directly in the battery storage sector.

Australian Vanadium’s (ASX:AVL) VSUN subsidiary develops renewable energy storage solutions using VRFB technology.

In January 2021, the company reached an agreement with a Chinese manufacturer to appoint a local designer to prototype a residential VRFB for the Australian market.

It has also ordered VRFBs from Singapore’s V-Flow Tech for both a regional residential customer and the Beverley Caravan Park in WA.

Meanwhile, Lithium Australia’s (ASX:LIT) VSPC subsidiary designs, manufactures and supplies cathode formulations for the lithium-ion batteries and other high-purity, high-performance metal oxides.

This includes the recent development of lithium ferro phosphate cathode powders.

The company also has a 50 per cent stake in Soluna Australia, which makes battery storage systems for residential and industrial applications.

Redflow (ASX:RFX) is a developer of zinc bromine flow batteries that have 100 per cent daily depth discharge capabilities and high energy density relative to lead-acid batteries.

The company has already sold a 60-battery system to a WA-based stock feed provider that demonstrates how its large scale battery design can scale up to meet larger industrial requirements.

While just a little too big to be considered a small cap, Novonix (ASX:NVX) provides lithium-ion battery material development, equipment and services to more than 14 countries.

In February, it formed a partnership with Emera Technologies to develop and manufacture energy storage systems, targeting market opportunities in North America.