Need to pivot to LFP

[jesse boyd]

Slate needs to get everything right to be successful. NMC? Yesterday’s tech. LFP will have overproduction in the U.S. and could become very competitive. Hope they’re looking hard at that to replace their “low end” 54kWh NMC with a 70kWh LFP. More range, longer life, faster charging.

 

[percevaus]

I'm not going to hold my breath, but It looks like SK ON is starting domestic LFP production later this year. If Slate keeps that partnership then the next generation of Slates could have them as an option. Would love a retrofit for first gens.

 

[Letas]

LFP has lots of pros, but a big con is it's density.
Without looking into it deeply, I would imagine Slate would lose energy capacity on their already tiny battery, not gain it. It would likely require a complete redesign to make space for that battery.

 

[ElectricShitbox]

LFP has lots of pros, but a big con is it's density.
Without looking into it deeply, I would imagine Slate would lose energy capacity on their already tiny battery, not gain it. It would likely require a complete redesign to make space for that battery.

They likely wouldn't be able to get 84kwh of LFP in the same pack they have 84kwh of NMC, but they could probably get 60-70kwh. They could definitely do 54kwh of LFP, so the two batteries are two different chemistries, but I'm guessing it ends up cheaper/simpler to focus on one chemistry at a time. If it were my decision, I would have skipped the small/big battery option and just used 60-70kwh of LFP. But sourcing LFP from anywhere other than china is still messy, so I see why they went with what they could get.

 

[percevaus]

Yes, LFP has lower energy density. It would be cool to be able to compare packaging to see what the actual fittable LFP kwh could be.

 

[Vyndralys]

I think LFP would make more sense in the lower range model since charging up to 100% doesn't affect longevity as much for LFP and the lower density wouldn't be an issue.

 

[ElectricShitbox]

Yes, LFP has lower energy density. It would be cool to be able to compare packaging to see what the actual fittable LFP kwh could be.

You can look at vehicles that offer both to get an idea. For example the Mustang Mach E has a 98kwh NMC pack or a 78kwh LFP pack, so about 80% of the capacity in the same packaging. That would put a Slate big pack around 67kwh if it were LFP. That's just rough guessing, but that's about the size of the LFP pack in the updated Bolt. Interestingly enough, that's around the same size as the NMC pack that used to be in the same packaging, so you can see where a few years newer technology has gotten us.

 

[The Weatherman]

It maybe that the smaller KWH LFP battery would provide nearly the same range due to it not requiring the buffer that
NMC does. Being able to charge 100% and discharge to near 0% might make up for the density difference.

I don’t have the numbers to do a valid calculation, but the logic seems sound.

 

[Johnologue]

NMC may be yesterday's tech, but the Slate was designed yesterday.
I imagine they'll update their chemistry when possible, but I'm not sure how they'll manage that against their existing supply contracts.

 

[AZFox]

Bear in mind that adding weight reduces load capacity.

 

[beatle]

I think Slate originally chose NMC for its availability in the US to qualify for the $7500 credit, and they may have only offered the smaller battery to make the sweet-sounding $20k price.

Now with the incentive gone, only offering a single "200 mile" LFP battery pack would streamline the config further and hopefully still keep the price low enough to be attractive. A lot of manufacturers are swinging to LFP, especially for their entry level models. Even Rivian's base truck is LFP.

The chemistry-only change of swapping NMC for LFP would really hit the standard range truck hard in the winter where its range will already be very low. Using the Mach-E NMC vs LFP math, you're down to 120 miles on the base pack at the best of times, then perhaps 30% off that in the winter which means under 90 miles - and that's when going from 100% - 0%. That's still enough for a lot of commutes and in-town errands, but travel would be a nightmare or borderline impossible for all but the most fearless.

 

[Orley]

NMC or LFP? I'll take the cheapest one that gives me around 70-80 kWh. I don't care about resale value because I will be keeping it for 8-10 years. Old school NMC battery technology might be more bulletproof and less prone to glitches. Maybe?

 

[TexasSlate]

NMC or LFP? I'll take the cheapest one that gives me around 70-80 kWh. I don't care about resale value because I will be keeping it for 8-10 years. Old school NMC battery technology might be more bulletproof and less prone to glitches. Maybe?

Historically, when battery packs have catastrophic failures (i.e., thermal runaway leading to a fire), it's the NMC chemistry. LFP is inherently less prone (but not completely immune) to this particular problem.

 

[phidauex]

LFP is not inherently better than NMC. It is lower energy density, it has a higher initial degradation, and in most cases, a lower end of life SOH (more total degradation).

Neither NMC or LFP can be run 100% to 0% in an EV application. All EVs "hold back" some SOC on the top and the bottom of the range, because discharging to a true 0% would damage the batteries and require a manual recharge of the pack, and charging to a true 100% requires switching to constant voltage charging mode rather than constant power, which requires controls that you wouldn't want to implement in a standard charger.

Both NMC and LFP degrade faster at high SOCs, but LFP needs to be charged to a "displayed" 100% (which is probably more like 95% of the chemical SOC) periodically to calibrate their BMSs due to the flatter voltage curve. The "NMC has to be kept between 80% and 20% but LFP can go 100% to 0%" that you hear sometimes is not true. At best it is an exaggeration, and at worst, outright misleading.

 

[catiare]

LFP is not inherently better than NMC. It is lower energy density, it has a higher initial degradation, and in most cases, a lower end of life SOH (more total degradation).

Neither NMC or LFP can be run 100% to 0% in an EV application. All EVs "hold back" some SOC on the top and the bottom of the range, because discharging to a true 0% would damage the batteries and require a manual recharge of the pack, and charging to a true 100% requires switching to constant voltage charging mode rather than constant power, which requires controls that you wouldn't want to implement in a standard charger.

Both NMC and LFP degrade faster at high SOCs, but LFP needs to be charged to a "displayed" 100% (which is probably more like 95% of the chemical SOC) periodically to calibrate their BMSs due to the flatter voltage curve. The "NMC has to be kept between 80% and 20% but LFP can go 100% to 0%" that you hear sometimes is not true. At best it is an exaggeration, and at worst, outright misleading.

You are 100% right. I never understood the LFP buzz, except maybe the safety angle. Costs is relative too, perhaps in China but here the economies of scale favors NMC. Anecdotally I had both a Tesla M3 LFP and an NMC and while I could charge to “100%” the LFP version total range miles was less than the NMC charged @ 80%. And at this point we may as well jump to sodium - they work much better in cold temperatures.

Edit: Also, the NMC accelerated faster and charged faster as well. Something to do with discharge capacity.