Higher temp charging for better battery life

[Rogue Synapse]

I ran across this article today:

Asymmetric Temperature Modulation for Extreme Fast Charging of Lithium-Ion Batteries - ScienceDirect

The article is titled “Asymmetric Temperature Modulation for Extreme Fast Charging of Lithium-Ion Batteries.

Engineers from Penn State published a study showing increased efficiency of fast lithium ion battery charging at higher temperatures. We knew that; it’s why on-route battery warmup was such a boon to Supercharging. The interesting thing is their finding that the infamous lithium plating - the thing that plagues all of our batteries and is the main underlying cause behind progressive loss of capacity - doesn’t occur much at temperatures above 50 deg C. A temperature which, if I recall correctly, is the target temp for Max Battery Power in performance Teslas with Insane+/Ludicrous+. Makes you wonder if heating your battery all the way up with Max Battery Power prior to charging might extend the life of your battery...

 

[RIP1]

Interesting you should ask tesla for a response. If it was true how can we effect the temperature of the batteries? Is that not preset in tesla software.

 

[KyleDay]

Very interesting. I imagine my battery is regularly close to this warm here in Arizona.

 

[SSedan]

Battery is whatever temp Tesla wants it to be. Remember it can be cooled to so you can have little impact on what the temp is.

 

[BigNick]

I think this has merit, but the on-board battery heater takes far too long to get a battery to “Max Battery” temperature for the Supercharger to wait to charge until the battery reaches that temperature.

With a battery starting around 50F to 59F (10C to 15C) as my battery is in the morning this time of year, it takes more than an hour to get to the 113F/45C Max Battery level (which I believe used to be 122F/50C prior to 2019.16).

The route-based heat could be tweaked, but that has to be balanced with the energy needed to get the car to the SC. I very rarely SC my car, so I don’t know how much the route-based heating adds to the battery or what it’s target temperature is.

I think the on-board battery heater is insufficient for this purpose. Adding radiant heating elements to SC stalls to heat battery packs may work but vastly increase costs and complexity. I don’t know how much heat output the SC heaters would need to output but I’m sure it would be more than the 6 kW of the onboard heater.

 

[SSedan]

And it is a car despite some folks have delusions about Tesla being 500k mile plus cars, it is a car and wears out.

Even if the motor or battery the parts that differ from ICE are 500k capable and with batterygate and a significant number of early S having motors replaced I think we can say we have no evidence significant numbers of Tesla drivetrains will last that long. Before some koolaid drinkers point out the taxis, ICE taxis last that long too.

Now considering cars have a finite life and the amount of energy to heat a 1200lbs battery is significant it seems like burning a bunch of energy regularly to make a part of a car that the rest of it will wear out might not be a smart use of resources.

Here in Wisconsin just heating the battery to charge or have some regen in winter dramatically increases energy use. Warming it much more is just going to use a lot more energy.

 

[Rogue Synapse]

For sure I agree that burning an hours worth of resistive heating is definitely not energy efficient. I’m purely wondering about the hypothetical benefit of doing routine charging - not even Supercharging, just level 2 charging - at Max Battery Power temperatures.

Here’s a non-hypothetical scenario which could make some sense: I’m a member of the Southern Alliance for Clean Energy, which has a giant solar array at their headquarters and 4 level 2 (32 amp) EV chargers for unlimited solar charging for members. Because their headquarters is less than a mile from my house, I try to charge there as often as I can. Let’s say I burn an hour of energy with Insane+ Max Battery Power to bring my battery up to 50C before doing my weekly charging. It hasn’t resulted in increased emissions because I can just solar charge an extra 20 mins to make up for it, but maybe now my battery doing its routine weekly fill up at a higher temp (it’ll keep the battery hot while charging if Max Battery Power remains on) will result in less lithium plating and a longer battery life for my poor old 85 kWh battery.

 

[vickh]

Very interesting. I imagine my battery is regularly close to this warm here in Arizona.

I hear ya. I usually charge at night (cheaper TOU too) but I just got solar and wondering if it's better to charge in the day now??