"Hot charging" could charge an EV 80% in ten minutes and prolong lifespan to 1700 cycles

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It's a few months old, but I hadn't seen it here before. Here's a plain-language summary:

Oct. 30 (UPI) -- Engineers at Pennsylvania State University have developed a new lithium ion battery that can charge an electric vehicle in 10 minutes. The technology could offer electric cars an additional 200 miles of driving range, alleviating concerns of becoming stranded on long trips.

In order to encourage the adoption of electric vehicles by the average driver, electric vehicle makers have been trying to find ways to charge lithium ion batteries more quickly.

When the lithium ion batteries currently used in electric vehicles are charged at rapid speeds -- quickly taking on 400 kilowatts of energy -- they become vulnerable to lithium plating, the formation and growth of metallic lithium around the anode. Lithium plating diminishes the performance and shrinks the lifespan of lithium ion batteries.

Researchers at Penn State realized they could avoid this pitfall by charging batteries at elevated temperatures. Most batteries charge and discharge at the same temperature. In the lab, engineers charged batteries at a temperature of 60 degrees Celsius, or 140 degrees Fahrenheit. The batteries quickly cooled when discharged.


from https://www.upi.com/Science_News/2019/10/30/New-hot-charging-lithium-ion-battery-can-charge-an-electric-car-in-10-minutes/1971572451708/

Joule paper: https://sci-hub.tw/https://www.cell.com/joule/fulltext/S2542-4351(19)30481-7
 
When the lithium ion batteries currently used in electric vehicles are charged at rapid speeds -- quickly taking on 400 kilowatts of energy
And, there's this issue: kW are a measure of power, not energy.
 
cwerdna said:
When the lithium ion batteries currently used in electric vehicles are charged at rapid speeds -- quickly taking on 400 kilowatts of energy
And, there's this issue: kW are a measure of power, not energy.

You both know what they really mean - just read the linked journal paper.
 
Yes, but when I have to figure out what a "journalist" "really means" I don't consider them a reliable source - even when they link to one. I'm a bit tired of the Web's "DIY even if you have no grasp of language or idea of what you are talking about" ethic.
 
If you read the article, there are a couple of details you need to be aware of. The first is that the battery was rapidly heated to the temperature required and the second was that it was rapidly cooled after the charging session ended. A minimal amount of time was spent at a higher temperature and only while charging.
 
johnlocke said:
If you read the article, there are a couple of details you need to be aware of. The first is that the battery was rapidly heated to the temperature required and the second was that it was rapidly cooled after the charging session ended. A minimal amount of time was spent at a higher temperature and only while charging.


Yes, I'm having a bit of trouble seeing that battery being used in typical EVs.
 
LeftieBiker said:
johnlocke said:
If you read the article, there are a couple of details you need to be aware of. The first is that the battery was rapidly heated to the temperature required and the second was that it was rapidly cooled after the charging session ended. A minimal amount of time was spent at a higher temperature and only while charging.


Yes, I'm having a bit of trouble seeing that battery being used in typical EVs.
If you have a liquid cooled system, it's relatively easy. Internal heater elements heat the cells to temp, you rapid charge the battery, then turn the cooling system back on to cool the battery. Tesla actually does something similar if you use the trip planner to plot your supercharger stops. They intentionally allow the battery to heat up prior to arrival so it can accept a higher charge rate. Tesla doesn't heat the battery to 140 degrees but they do warm it up.
 
johnlocke said:
If you read the article, there are a couple of details you need to be aware of. The first is that the battery was rapidly heated to the temperature required and the second was that it was rapidly cooled after the charging session ended. A minimal amount of time was spent at a higher temperature and only while charging.

It would take a considerable amount of energy to raise and then lower the temperature of several hundred pounds worth of batteries that amount.
 
johnlocke said:
LeftieBiker said:
johnlocke said:
If you read the article, there are a couple of details you need to be aware of. The first is that the battery was rapidly heated to the temperature required and the second was that it was rapidly cooled after the charging session ended. A minimal amount of time was spent at a higher temperature and only while charging.


Yes, I'm having a bit of trouble seeing that battery being used in typical EVs.
If you have a liquid cooled system, it's relatively easy. Internal heater elements heat the cells to temp, you rapid charge the battery, then turn the cooling system back on to cool the battery. Tesla actually does something similar if you use the trip planner to plot your supercharger stops. They intentionally allow the battery to heat up prior to arrival so it can accept a higher charge rate. Tesla doesn't heat the battery to 140 degrees but they do warm it up.


It's that high temp, with all that battery mass, that makes it hard to imagine. The TMS would have to be huge, and power intensive.
 
LeftieBiker said:
johnlocke said:
LeftieBiker said:
Yes, I'm having a bit of trouble seeing that battery being used in typical EVs.
If you have a liquid cooled system, it's relatively easy. Internal heater elements heat the cells to temp, you rapid charge the battery, then turn the cooling system back on to cool the battery. Tesla actually does something similar if you use the trip planner to plot your supercharger stops. They intentionally allow the battery to heat up prior to arrival so it can accept a higher charge rate. Tesla doesn't heat the battery to 140 degrees but they do warm it up.


It's that high temp, with all that battery mass, that makes it hard to imagine. The TMS would have to be huge, and power intensive.
Doing the math for a 600 lb 30 KWH battery with a 40 deg. C rise and 960j/kgC thermal mass (li-ion 18650) I come out with about 3 KWH to heat the battery ignoring losses. About 10% Increase in power to obtain ultra fast charge. That also ignores internal heating of the battery from high currents so probably a bit less. Getting rid of the waste heat afterwards is probably harder to do. My math could be off just due to all conversions but that's the number I came up with. The power required to heat and cool is the same whether you charge a little or a lot. Only really useful if you charge from a relatively low level.
 
Oh good, another article about someone who has invented some new battery tech that will revolutionize EV charging.

Now all I need is another VW concept EV announced to make my day.
 
3kwh worth of heat is about 10,000 BTU.
When they say quickly heat and cool do they mean take an hour or take 5 to 10 minutes?
Because being able to move that much heat in an hour isn't something that is going to fit in a car. The car could heat it up its own battery that fast with resistance heaters but you would need an air conditioner almost the size of a car to cool it down in 10 minutes.
 
Oilpan4 said:
3kwh worth of heat is about 10,000 BTU.
When they say quickly heat and cool do they mean take an hour or take 5 to 10 minutes?
Because being able to move that much heat in an hour isn't something that is going to fit in a car. The car could heat it up its own battery that fast with resistance heaters but you would need an air conditioner almost the size of a car to cool it down in 10 minutes.
Cooling could be much slower than heating. You need to heat the battery quickly to do the rapid charge, cooling could be done more slowly after you drive off. I did say that getting rid of the waste heat would be a problem.
 
jlv said:
Oh good, another article about someone who has invented some new battery tech that will revolutionize EV charging.

Now all I need is another VW concept EV announced to make my day.
Ahhhhhh.
https://www.autoweek.com/news/future-cars/a30729440/volkswagen-has-come-up-with-an-electric-golf-r-and-its-testing-on-ice/
 
Oilpan4 said:
Because being able to move that much heat in an hour isn't something that is going to fit in a car. The car could heat it up its own battery that fast with resistance heaters but you would need an air conditioner almost the size of a car to cool it down in 10 minutes.

The Model 3 can reportedly maintain a speed of ~130 mph until the pack is empty. If its efficiency at 130 mph is 700 Wh/mile, its continuous power consumption is about 91 kW, and it thus has a heat rejection capacity (from resistive heating in the pack, not including motor) of at least 4600 W. Add in the heat generated by the motor (around 85-90% efficiency at 91 kW?) and you get around 15 kW total heat rejection. Taking that value from a linear point of view (obviously conductive temperature change isn't linear with time) it should only take around 20 minutes to take 3 kWh out of a hot pack with today's Model 3 TMS.

700 Wh/mile * 130 mph = 91 kWh/h = 91 kW.
I = 91 kW / 355V = 256 A.
M3LR pack R = 0.03 ohms / 42p * 96s = 0.07 ohms.
Heat power = (256 A)^2 * 0.07 ohms = 4.6 kW

Moreover, the Model 3 can reject that much heat while maintaining a battery temperature less than 45°C, regardless of ambient. Since conductive heat exchange is roughly linear with the difference in temperature, it should be substantially easier to cool off a pack at 60°C to 30°C, and in fact the Penn State research suggests cooling is 8-12x as efficient at higher temperatures.

So, in my view, achieving "hot charging" without long cooldown periods is more about tweaking coolant flow rates and radiator fan speeds on e.g. a Model 3 rather than a complete reinvention of the battery.
 
LeftieBiker said:
So the battery cooling process will involve driving the car at twice the speed limit, preferably in cool weather? ;)

If you look at the Model 3's aerodynamics, you can probably guess that its cooling power doesn't depend a huge amount on the speed. All the radiators are hidden underneath the fascia and body, so the differential thermal impact of high-speed could be replicated with a bunch of blower fans. But hey, we might see a surprising return to big grilles.

One other solution, which I suspect hasn't been patented yet, would be integrated station-vehicle coolant exchange: right after you finish charging, the station pumps far more superchilled coolant through the pack than could possibly be cooled or stored onboard, then fills it back up with room-temperature coolant once the pack is cool enough. You'd maybe need only a few hundred gallons in an insulated/chilled tank at each station...

This is close, but not quite what I'm talking about. After some searching, yep, looks like Tesla patented it a couple years ago.
 
Ars Technica article about using Bayesian Optimization to determine a charging profile that optimizes speed of charging vs lifetime of battery:
https://arstechnica.com/science/2020/02/using-machine-learning-to-figure-out-how-to-charge-your-gadgets-batteries/

One of the commenters on the Ars Technica article notes that a Tesla Model 3 will heat up its battery (to 55 Celsius using 7 kW heaters) to allow faster charging, and pre-heat the battery to 25 C when approaching a SuperCharging station if in-car route planning knows about the SC, and cool the battery back down to 25 C within ~10 minutes after charging, since constant high temperature would damage the pack.

Edit: Another commenter said, "Batteries are chemicals plus folklore." Amen to that, brother.
 
LeftieBiker said:
So the battery cooling process will involve driving the car at twice the speed limit, preferably in cool weather? ;)
No, It means running the radiator fans at high speed for a while. Often done by Teslas during charging. It's actually one of the more common noise complaints. Cool weather does help though :lol: .
 
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