Energy Density: Energy density, defines battery capacity in weight (Wh/kg).
Specific power: indicates loading capability. Batteries for power tools are made for high specific power and come with reduced specific energy (capacity).
Figure 1 illustrates the relationship between energy density (water in bottle) and specific power (spout opening). It's the ability to deliver a high current and indicates loading capability. The water in the bottle represents energy density (capacity); the spout pouring the water govern specific power (loading). AA battery can have high specific energy but poor specific power as is the case with the alkaline battery, or low specific energy but high specific power as with the supercapacitor.
Performance: This measures how well the battery works over a wide range of temperatures. Most batteries are sensitive to heat and cold and require climate control. Heat reduces life, and cold lowers performance temporarily.
Lifespan: This reflects cycle life and longevity and is related to factors such as temperature, depth of discharge, balancing, and C rating. Hot climates accelerate capacity loss. Cobalt blended lithium-ion batteries also usually have a graphite anode that limits the cycle life.
Safety: This relates to factors such as the thermal stability of the materials used in the batteries. The materials should have the ability to sustain high temperatures before becoming unstable. Instability can lead to thermal runaway in which case NMC can blast and catch fire while LiFePo4 emits fumes only. Fully charging the battery and keeping it beyond the designated age reduces safety.
Cost: Demand for electric vehicles has generally been lower than anticipated and this is mainly due to the cost of lithium-ion batteries.
Lithium Nickel Manganese Cobalt Oxide (NMC)has two major advantages as compared to the other batteries. The first one is its high specific energy which makes it desirable in electric powertrains, electric vehicles, and electric bikes. The other is its low cost. It is moderate in terms of specific power, safety, lifespan, and performance when compared to the other lithium-ion batteries. It can be optimized to either have high specific power or high specific energy.
Lithium Iron Phosphate only has one major disadvantage when compared to other types of lithium-ion batteries and that is its low specific energy. Other than that, it has moderate to high ratings in all the other characteristics. It has high specific power, offers a high level of safety, has a high lifespan, and comes at a low cost. The performance of this battery is also moderate. It is often employed in electric motorcycles and other applications that require a long lifespan and a high level of safety.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.How Long Do EV Batteries Last? | I Speak Electric