[stop-eject]

Battery logs show maximum available power levels.

Discharge/Charge Power Available:
   HV Battery Charge Power 2sec: 97257 W
   HV Battery Charge Power 10sec: 95040 W
   HV Battery Charge Power 30sec: 83961 W
   HV Battery Discharge Power 2sec: 97374 W
   HV Battery Discharge Power 10sec: 95073 W
   HV Battery Discharge Power 30sec: 91794 W

I avoid driving 75MPH in electric mode. Discharging the entire capacity in 10 min can't be good for the battery health.

 

[stop-eject]

So? The issue is total sustained power output, and if that's bad on the battery. Call me crazy but I have a feeling that an automotive high voltage battery was probably engineered with freeway speed travel in mind.

I don't want to dig into numbers, generally Li-Ion batteries are not well suited for intensive fast discharge operation. LiFePo4 chemistry is better at this task, you'll find it in the starting batteries, high torque power tools, drones, etc... Pachy uses large pouch cells cooled from the bottom. The top parts of the cells will get hot under fast discharge. The range at 75MPH is nowhere near 32 miles, which means the battery will discharge in 15-20 minutes. Its not going to kill it instantly, but will certainly contribute to its degradation.

 

[stop-eject]

If you have to

As someone who often watches the power flow data, I can tell you that power output at freeway speeds is often in the 20-35kW range.

That can't be true for 75MPH. When the entire 12kwh is used in 15-20 minutes, the sustained power has to be 36-48kw.

 

[stop-eject]

I don't think anything particularly bad will happen if you drive fast occasionally. I was in these circumstances when I spent a night in a hotel next to I-95, where I had to drive in the morning. But imagining other extreme- commuting at 75MPH and charging at work, the degradation will accumulate.

 

[stop-eject]

Says who? Can you prove it? Or do you just feel like that’s true?

And just saying degradation will accumulate is kind of a nothing statement. Degradation accumulates with any usage of a battery. I’m still waiting for any proof that driving at a normal speed for a vehicle will cause exceptional battery degradation that anyone would actually notice.

ShieldSquare Captcha Skip to the "current derating' part. Notice that the optimum rate of discharge is 1C, which for us is 14-19kw, depending on SOC.
Lithium ion battery degradation: what you need to know - Physical Chemistry Chemical Physics (RSC Publishing) DOI:10.1039/D1CP00359C is more about the battery chemistry but mentions that high currents and temperatures contribute to degradation. PacHy cells are large and are cooled only from one side. They are capable of absorbing the heat generated by high currents during acceleration, sustained high currents will saturate them and cause local overheating.

 

[stop-eject]

Thanks for doing the test. It is in line with my best estimates. It is quite impressive that PacHy can still have about 25 miles of range at 75MPH in a cold weather and on winter tires.