Lucid's Charging Curve, can it be improved via OTA update?

[rfc805]

In this case it actually has nothing to do with voltage (well, it does, but in a different way), but just a matter of C rate. Temperature is relevant, but there's no temperature which prevents it, there's just an ideal temperature which makes it least likely. Which is what pre-conditioning does for us. Thermally there's little difference between doing 200kW at 400v and 800v, it's still 200kW and you're probably losing like 10% of that 200kW to heat or somewhere around that, regardless of voltage. Voltage does let you do 200kW with thinner conductors as you mentioned, but the heat loss is still essentially the same. It just lets you put more cooling material in the same space where the smaller conductor now is. If you were already meeting your thermals with the 400V conductors, it won't matter though.

He explains it better than I can, but there is no magic solution. Even with perfect thermals, if you charge at a high C rate even at 70-80% SoC, you will (probably) degrade the battery significantly. It's worth a watch.

 

[BS8899]

In this case it actually has nothing to do with voltage (well, it does, but in a different way), but just a matter of C rate. Temperature is relevant, but there's no temperature which prevents it, there's just an ideal temperature which makes it least likely. Which is what pre-conditioning does for us.

He explains it better than I can, but there is no magic solution. Even with perfect thermals, if you charge at a high C rate even at 70-80% SoC, you will (probably) degrade the battery significantly. It's worth a watch.

It is more than temperature. Oxidation/reduction processes are accelerated (or retarded) by temperature (thermodynamics). But remember, oxidation/reduction (plating/erosion) is about gaining/losing electrons, hence the voltage.

 

[rfc805]

Yes, but in this case, the plating effect is actually a secondary effect, not a primary effect. The transfer of li-ion is intentional in this case, not an erosion effect, but the actual battery chemistry. The problem is when the overall rate is too high, they "miss" their intended target and plate the conductor instead. That's part of why it's a probability versus a certainty - if it were just like electro plating, it'd be a guaranteed result, but this isn't that, it's battery chemistry, where you're doing a very similar thing, but with an intended target of graphite material.

But seriously - try his video, because I'm not doing anywhere near as good a job as he does.

 

[BS8899]

Yes, but in this case, the plating effect is actually a secondary effect, not a primary effect. The transfer of li-ion is intentional in this case, not an erosion effect, but the actual battery chemistry. The problem is when the overall rate is too high, they "miss" their intended target and plate the conductor instead. That's part of why it's a probability versus a certainty - if it were just like electro plating, it'd be a guaranteed result, but this isn't that, it's battery chemistry, where you're doing a very similar thing, but with an intended target of graphite material.

But seriously - try his video, because I'm not doing anywhere near as good a job as he does.

I watched the video. I don't disagree with the contents. The author looked at extreme ranges of temperature and charging rates in order to elucidate/exaggerate the degradation mechanisms. This is helpful in understanding the mechanisms. That said, it is not just about temperature. There is an electrochemical process at play simultaneously. A simple way to think about it is to think back to your high school chemistry demonstration of electrolysis of water. The author was using extremely conditions (e.g., 10X over SoC limit) to illustrate the adverse mechanisms at play.

However, I think we are talking pass each other. We are talking about a much narrower range of parameters:
> we follow the manufacturer's directions. No one is advocating to continuously overcharging the battery.
> we follow the directions for preconditioning.
> when I charge my car to 100% SOC, I only do that hours before I depart on the 1st leg of my road trip.
> other than on long road trips, I only charge to 80% SoC.
> My EVs are not charged to 100% SoC and left sitting at 50 degree C for any length of time.

The original question I posed in his tread was whether there is a better way to optimize the charging/discharging curve on the Lucid while not exceeding the manufacturer's recommended specs.