Battery choice should take into consideration safety, overall cost of ownership and environmental safety. Common types of batteries used to store solar energy include lithium-ion, flow, lead acid, and nickel cadmium.
Lithium-ion batteries have a long lifecycle, are low maintenance and popular for residential battery energy storage systems.
Flow batteries are an emerging battery technology using a water-based solution of zinc bromide. They operate well in hot climates (but not cold) and are more suited to large-scale systems. They’re relatively expensive to buy and maintain but are easy to recycle.
Lead acid batteries have been around a long time so are cheap, reliable and have established systems for disposal and recycling. However, they have a shorter lifespan and are higher maintenance. They’re more temperature-sensitive and have a slower charge cycle.
Nickel cadmium batteries are more expensive compared with lead acid batteries and contain highly toxic chemical components. They are difficult to maintain but have a long service life.
LFP and NMC lithium-ion batteries: what’s the difference?
Lithium-ion batteries are commonly used for residential or business battery energy storage systems, however it’s important to know that not all lithium-ion batteries are alike in chemistry. Two major types on the market are lithium ferro phosphate (LFP) and nickel manganese cobalt (NMC).
NMC batteries are a newer technology and can be charged at a higher, faster rat; however, this does generate more heat. The chemistry of this battery and its lower flashpoint means there is a higher risk of catching fire due to thermal runaway (an uncontrollable increase in temperature). Nickel and cobalt are rare and expensive, and mining and disposal of these elements is environmentally problematic.
LFP batteries use lithium iron phosphate chemistry and are the safest option. They are more stable chemically and thermally, so they are at a very low risk of catching fire. The use of iron, which is a more plentiful element, means LFP batteries are both are cheaper and less toxic than their counterparts.
LFP batteries have both a lower energy density and lower operating voltage NMC batteries. However, they have an excellent life cycle – approximately four times that of NMC batteries – and are suitable for a wide variety of climates.
RedEarth’s Troppo battery is an LFP battery.