There are several different types of batteries available on the market to provide battery backup power to your home. Different battery types have different “chemistries”.
Lead acid batteries
Lead acid batteries have been around a long time. They’ve powered cars, tractors, submarines, and have been used to provide backup power to homes and buildings. The most common variety of lead acid batteries for backup power is called “sealed lead acid”. These types of lead acid batteries do not require regular maintenance to keep them operational, unlike their “flooded lead acid” cousins. Lead acid batteries have a lower upfront cost than newer lithium-ion batteries. They also take up more space than newer options. Depending on how often they are used (or “cycled”), they can last from 5 to 10 years.
The market for lithium-ion batteries is growing rapidly and prices are dropping. The technology offers a higher density of energy (more energy per unit of space) than traditional lead acid batteries and can be used (or “cycled”) more often during their lifespan. The upfront cost of lithium-ion batteries is higher than that of lead acid batteries. However, because of their longer lifespan (~ 10 years) and their ability to be charged and discharged more frequently, lithium-ion batteries have a lower lifetime cost than lead acid counterparts.
Two main types of lithium-ion batteries on the market:
Lithium Nickel Manganese Cobalt Oxide or “Li-ion-NMC” is the more commonly available lithium-ion battery type and is the least expensive lithium-ion battery on the market. It is important to recognize that Li-Ion-NMC batteries can overheat and catch fire in rare cases of overcharging or improper use. This is known as “thermal runaway”. You may have heard of this phenomenon with cell phones, e-cigarettes, hoverboards, and other small consumer devices. However, home battery storage systems include sophisticated management software that is designed to prevent overcharging and thermal runaway problems. To date, there have not been any examples of home storage systems catching fire.
Lithium Iron Phosphate or “LiFePO” is more expensive than the Li-ion-NMC variety. This chemistry, however, does not experience thermal runaway and does not contain cobalt, whose mining practices, especially in the Congo, have come under scrutiny in recent years.