LFP or NMC: Which battery type is right for you?

Source: Flash Battery

We see a lot of batteries being manufactured in today's time. These batteries are used in large quantities in various EVs sold in Indian Market. People have lots of confusion that all EVs have same technology of batteries. But its not true. All EVs are having different type of battery technology. We will be focusing on mainly 2 types of battery chemistry commonly used in EVs, which are NMC and LFP battery chemistry.

Lets discuss these battery chemistries one by one so that you can choose the one which best suits your requirements.

1. LFP (Lithium Iron Phosphate): As the name suggests, it is a type of lithium ion battery which is having iron in its chemistry. Though EVs started primarily with the use of NMC battery chemistries, LFP batteries soon captured attention due to large amount of benefits which they offer over NMC chemistry. We will be discussing several pros and cons of LFP battery here. We wont be discussing details about LFP battery chemistry and how it works in this article. Its being left for one more selerate article as LFP chemistry is too complicated to understand by someone who isnt from the technical background.

Pros of LFP batteries:

a. Longer Life - As per recent study, LFP batteries can survive upto 2000 to 2500 cycles of operation even under worse condition. Considering that it has substantially longer life than NMC batteries one can consider it ideal for EV cars as it will outlast the life of an car.

b. Better Thermal Stability - LFP batteries are more resistant to outside temperature and environmental extremeties. Also its considered that LFP batteries are more stable at 100% as compared to NMC batteries. Hence, LFP batteries are more preferable to be used in countries which are having extreme climatic conditions.

c. Higher thermal runaway - LFP batteries have a thermal runaway temperature of 280 degree celcius. This temperature is very hard to reach in realistic conditions. Hence, one might find rare battery failure issue due to thermal runaway in NMC, but when compared to LFP, NMC is little more prone to thermal runaway.

d. Ability to charge to 100% everytime - This benefit is very useful for people who travel alot using their car. Ability to charge to 100% gives them wide set of range which will benefit them to travel longer distances.

Cons of LFP battery:

a. Complex Chemistry: LFP chemistry is quite complex as compared to NMC. As a result, one needs strong BMS to manage the LFP battery pack. Also its very difficult for active cell balancer to manage LFP batery packs.

b. Charge to 100% always: When your vehicle has LFP battery chemistry, you are supposed to charge to 100% always whenever you charge your car. Thats because of cell balancing and SOC calibration. Incomplete charging too many times can disblaance your battery or lead to your vehicle show wrong SOC in your Car.

c. Aging of your battery: Lots of people are mesmerized by the large number of cycles offered by LFP batteries. They starts to think that their batteries will last lots of years looking at the number of cycles which it offers. But the aging of Lifepo4 batteries is not only dependent on cycles but also time period. So if someone with low running buys car with Lifepo4 battery thinking it will last 100 years then they are definately mistakened.

d. Lower Energy Density: LFP batteries have relatively lower energy density as compared to its NMC counterpart. Hence, for the same amount of space available in EV car, lower kWh of total battery pack can be installed. To install same kWh of battery pack, as same as NMC one would require substantially larger space in EV.

2. NMC Batteries (Nickel Manganese Cobalt Oxide): It is also one kind of Lithium ion battery. NMC batteries are very popular kind of lithium ion batteries used in various applications. Some of its common applications include mobile batteries, laptop batteries, high performance EV cars. Currently NMC is the most famous battery chemistry used in EVs. Now lets discuss some pros and cons for having NMC battery chemistry in your EV.

Pros

a. No need to charge to 100% always: If your NMC battery has active cell balancer, then you can always use them between 20 to 80% if that suffice your needs. It will also prolong the life of NMC batteries. If your car doesn't have active cell balancer, then even NMC batteries are required to be charged to 100% like LFP batteries. But still it won't require 100% charging as often as LFP battery chemistry packs.

b. No battery complexity: There are numerous issues of cell balancing, memory effect, SOC calibration in case of LFP battery chemistry. No such complexity exists in case of NMC battery chemistry. We will be discussing these complexities in LFP battery chemistry in future articles.

c. Higher Energy Density: NMC batteries have higher energy density as compared to LFP batteries. Hence, more kw of battery cells can be fitted in the same amount of space as compared to LFP batteries.

d. Higher Fast Charging Speeds: NMC offers fast charging speeds upto 2.5C as compared to slower Fast Charging speeds of LFP batteries. Hence, lots of people who does long distance travel prefers NMC batteries over LFP batteries.

Cons

a. Thermal Instablity: NMC batteries are more thermally instable as compared to LFP batteries. Though some people gets scared by this thermal instablity affecting safety. But with proper termal management system even this can be handled properly.

b. Lower Cycle Life: NMC btteries has lower cycle life as compared to LFP batteries. On an average NMC batteries gives 1200 to 1500 cycles before its range falls to 80% as compared to new.

c. More degradation in extreme climates: NMC batteries are likely to face more degradation when outside temperature is either above 40 degrees or below 10 degree celcius. Hence, NMC batteries requires proper thermal management system to maintain them healthy.

Conclusion

As we have discussed, pros and cons of LFP and NMC batteries, it will become easier for people to choose the right battery tech which will meet their requirements. Lots of people who have the facility of home charging and does long distance travel once or twice a year only, would prefer LFP batteries over NMC batteries, because of the longer life which they have to offer.

People who often does long trips and prefers lower charging stop times would go for NMC battery chemistry with active cell balancer. Some people doing longer trips also prefer LFP over NMC as it allows to charge all the way up to 100% everytime which allows more range to offer per charge, even with lower battery capacity.