In our previous post, we covered some of the factors that should be taken into account when considering a battery storage system (BSS). Today, we’ll explore several popular battery technologies. Note, all values are approximations based on a variety of market offerings in the US and may not reflect current market offerings, geographical location, or other factors.
The two best established battery technologies are Lead Acid and Lithium Ion (Li-ion). Sodium-ion batteries (SIB) are also becoming popular as a non-toxic energy-dense alternative to Li-ion batteries. More exotic battery types are available, but are typically less common.
There are many factors to consider when exploring different batteries technologies, including:
- Energy density (physical dimensions of the battery in relation to storage capacity)
- Cost per kWh of storage capacity
- Environmental impact
Lifespan (measure in charge cycles)
- Li-ion: 1000 - 5000 cycles (depending on production date)
- SIB: 3000 cycles
- Lead Acid: 200 - 1000 cycles
In most usage scenarios, Lithium Ion batteries have a clear advantage. Remember, deep cycles (where the battery is almost completely discharged before recharging) and high temperatures will shorten the life of Lead Acid and Li-ion batteries.
Cost per kWh of Capacity
- Lead Acid - $
- Li-ion - $$
- SIB - $$$
Lead Acid batteries are significantly cheaper than their Li-ion and SIB equivalents. However, they usually have higher maintenance requirements and shorter lifespans.
- SIB: 300-400 Wh/kg
- Li-ion: 110-350 Wh/kg (depending on production date)
- Lead Acid: 30-50 Wh/kg
SIB or Li-ion batteries have a clear advantage here as well, since energy density translates directly to the weight and physical size of the batteries. For example, a 5kWh SIB bank would weigh about 30lbs, while an equivalent Lead Acid bank would weigh 220lbs.
|SIB||Non-toxic, non flammable, relatively stable||Not well established, less effective storage solution|
|Lead Acid||Recyclable, established technology||Generate explosive gasses, highly toxic|
|Li-ion||Recyclable, established technology||Limited supplies of Lithium, highly toxic, flammable when exposed to water|