Are LFP batteries better than NMC?

A reader despatched us this query:

Hello workforce

The brand new Xpeng G6 presents 2 fashions. The bottom mannequin has a LFP battery and the highest mannequin has a NMC battery with greater vary. Aside from vary what are the advantages of 1 over the opposite?

I perceive LFP is safer (much less danger of fireside) and will be charged absolutely and will be quick charged with much less danger of long run harm to battery. I additionally perceive NMC is advisable to solely sluggish cost to full and principally to cost to 80%.

Are there every other causes to desire one over the opposite?

Thanks in your fabulous web site. I’m a day by day reader.

Des

Hello Des – you ask an excellent query! There’s loads of confusion concerning the deserves (or in any other case) of the 2 major sorts of EV battery. The brief reply is that it’s a matter of ‘horses for programs’, however neither is a short-priced favorite.

The longer reply, is, er, a bit longer. I’ll begin by explaining the broad variations between LFP and NMC battery chemistries after which take a look at whether or not these variations make any important influence on EV selection.

LFP stands for lithium iron phosphate (chemical formulation: LiFePO4). LFP refers back to the materials the cathode (constructive finish of a cell) is fabricated from. NMC refers to a variety of associated battery cathode supplies involving mixtures of nickel, manganese and cobalt. (Basic chemical formulation: LiNixMnyCo1-x-yO2).

As you possibly can see from the chemical formulae – NMC batteries embrace each cobalt and nickel within the combination, LFP don’t. As cobalt and nickel are provide constrained, they’re each comparatively costly. This makes NMC batteries costlier to provide than LFP. Alternatively, each are lithium-based batteries, so lots of their power storage and use properties are related.

As LFP batteries are comprised of available (and cheaper) supplies, they’re cheaper to provide, however the down-side is LFP chemistry leads to a decrease power density. (i.e. what number of kWh {of electrical} power storage you possibly can squeeze right into a given quantity or mass). This does nevertheless make LFP ultimate for producing cheaper decrease vary EVs. (As in comparison with becoming an EV with an NMC battery of the identical kWh score).

Alternatively, the place the house for a battery is constrained and/or to scale back the general mass of the automobile: NMC is the selection as you will get extra kWh right into a smaller house. It’s going to even be lighter than an equal kWh measurement LFP one.

That is the primary motive producers select one chemistry over the opposite. Longer vary EVs usually include NMC batteries and shorter-range ones LFP. The opposite motive an EV could also be fitted with an LFP battery is that China leads the world in LFP battery chemistries – so just about any EV from a Chinese language producer could have an LFP battery except they’re actually constrained for house within the longest vary variations (such because the long-range Xpeng G6 you point out).

Now we come to the advertising and marketing. Sure, LFP batteries have longer lives. (Round 2,500 to 9,000 charge-discharge cycles versus roughly 1,000 to three,000 cycles for NMC). Nonetheless – if on common you cost your EV as soon as each week or two from 0 – 100% (which is nicely above the typical use): in 20 years that equates to 520 to 1,040 cycles.

This implies for the overwhelming majority of automobile house owners, the lifespan distinction between the 2 is irrelevant. Alternatively, high-mileage vans could also be higher served with LFP batteries, supplied the burden penalty was not a difficulty. (It’s value noting right here that the following technology of LFP batteries will doubtless have each a better power density and a diminished lifetime of round 5,000 cycles most).

The opposite large advertising and marketing ploy from the LFP EV producers is the hyping of a hearth security distinction between the 2. Sure, LFP is considered one thing like 10 occasions much less doubtless to enter thermal runaway than NMC. The massive BUT right here is that BEVs are far much less prone to burn than an ICE automobile (see articles right here and right here) – so in case you are blissful to drive a petroleum automobile now, a battery EV is a a lot safer selection already, regardless of chemistry.

Basically, regardless of the advertising and marketing (and trolling): in the case of EVs and fires, it isn’t a selection between a ‘doubtless hearth with NMC’ and ‘no hearth with LFP’. Each battery chemistries are a lot much less fire-prone than ICE autos, plus LFP isn’t ‘fireproof’.

Charging velocity can also be barely completely different between the 2: NMC cells have each a better particular person cell voltage and will be charged sooner than LFP, so for actually fast-charging vehicles just like the Hyundai Ioniq 5 that has a 77kWh, 800V battery for as much as 230 kW DC charging – NMC is the one selection.

Alternatively, smaller batteries naturally don’t take as lengthy to cost, so while an LFP battery could have a decrease DC cost charge, the distinction in time gained’t be very noticeably for a 40 to 50kWh battery of both chemistry.

With regard to charging to 100% or not being a motive to decide on between the 2: NMC batteries final greatest (degrade least) if they’re usually saved between 20% and 80%.

That doesn’t imply you possibly can’t go beneath/above these (say for an extended journey): simply don’t go away them beneath 10% or above 90% for prolonged durations. LFP then again is meant to be extra tolerant of being left at 100% – nevertheless the automobile producers additionally specify that they should be usually cycled as much as 100% for the battery administration system to function successfully.

One different level to make is when utilizing a DC quick charger, the 80% rule is etiquette (not battery longevity administration) and applies to each NMC and LFP. It is because after round 80%, each begin to decelerate their cost charge. Consequently, to get the quickest charging time (and let others get a cost sooner) NEVER cost at a DC charger previous 80% except there’s no-one else there AND you really want the additional to get to the place you’re going.

(By the best way: After round 90%, for a 3 section AC charging succesful EV – an AC charger will in all chance be as quick or sooner anyway). As well as, the stats coming in now are that neither battery kind degrades sooner as a result of numerous DC charging – so charging velocity affecting NMC life greater than LFP is wanting like a Furphy.

Summing up – bigger, sooner charging (and costlier) EVs use NMC batteries to take benefits of the traits inherent in NMC chemistries. Smaller battery EVs make use of LFP as a result of they are often made cheaper and are much less constrained by the necessity to squeeze in as many kWh of storage as will be fitted into the obtainable house.

LFP additionally has the benefit of some discount in (the extraordinarily unlikely) hearth dangers of an EV in addition to apparently being extra tolerant of being left at 100% cost. Alternatively, LFP does have the drawback of a slower DC cost charge and slowed AC and DC cost charges in chilly climate.

Put by way of BEV selection: if you would like a super-fast charging, lengthy vary EV, your decisions will all have NMC batteries. If you’re a less expensive EV with cheap (however not the longest) vary and a barely slower DC cost charge – your decisions will doubtless all have LFP batteries.

In case your selection of BEV is from Europe, it’s extra prone to have NMC no matter its vary, and the reverse if it comes from China. Nonetheless, as LFP evolves, it might very nicely catch as much as NMC in power density and cost velocity – which means that being cheaper, LFP could very nicely win out ultimately. We will have to attend and see there.

Personally, I wouldn’t select a automobile primarily based on its battery chemistry. Select one which does what you need by way of driving vary, value, charging velocity and model … and the chemistry will comply with as it would have been chosen by the producer to be the very best one they make for the use-case.