Which battery chemistry for extreme climates?

Hi all, I'm trying to determine which battery chemistries would be safe for year-round use in Vermont. We get temperatures here as low as -40c occasionally, and there are typically several weeks each year where the daily high temperature is below -20c (approx 0f).

My understanding is that most lithium chemistries can be quite dangerous when charged at these temperatures due to lithium plating forming on the anode (?). A chemistry like NiMH by comparison will, as I understand it, just warm up when charged at low to moderate currents in extreme cold.

I've had a hard time finding good information on this topic. Can someone please either point me to a good source, or give me a rundown on how different chemistries behave in extreme cold and could be used year-round?

Lithium titanate seems to do OK at low temps, but the energy density is pretty ordinary.

Thanks. I understand most EVs have heating elements in the batteries which turn on in northern climates? What do those EVs do that don't have heating elements? Do you just not get any regen until the battery warms up? Can you not charge them at all?

^^ Hehe... Hi VT... MOST "EV"s as bikes have "small" batteries watt can be removed to be stored and recharged "in" doors where it's usually warm/heated... yes? :wink:

This is an automotive application. Non-removable, otherwise temperature wouldn't concern me.

Hehe... an "automotive application"... suspect a "huge" battery... plus hard to pedal. :wink:

LockH said:

Hehe... plus hard to pedal. :wink:

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Hehe... I haven't pedaled in months. :wink:

Watched a YT vid on that rebel Tesla junk builder, black fellow, Rich I believe.
He upgraded to top level charging, fixes junk Tesla's and did a video on Tesla in winter.
Yeah they seriously degrade, have to let them warm up, even putting the heater on takes out a ton of juice.

For an EV you'd have to plug it in, and install a heater where i.c.e. uses block heater plugin.
Other then that, I dont think EV's are meant for winters, do as Chalo says and move to warmer climates.
Or have two batteries, one ev battery and one battery for the warmer, warming both batteries.

Or use a gasoline generator to heat the ev battery.

Check out the capabilities of the A123 cells. If they don't do what you want, you can check LiFePO4 off the list of contenders as you won't find more capable cell in that chemistry.

jonescg said:

Lithium titanate seems to do OK at low temps

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This Russian guy did some garage tests of LTO cells in a small fridge.
[youtube]9-l7-1J6te4[/youtube]
He found out that the temperature should be not lower than -15°C to keep the efficiency high. In case of -15°C you need to spend 10% of their energy to heat them up to make them give the highest current they are able to give.
When the temperature is lower than -15°C you'll need to spend way too much energy on heating up.

I'm mostly concerned about charging during these temps. Will check out A123's though.

This is a good question, I was trying to find something about this topic too. I also run some tests at -20°C with A123 and Boston Swing 5300mAh cells. Generally you can somehow charge all lithium chemistries at cold temperatures but you have to apply a charging current derating. There is no "wall" at for example 0°C, where lithium plating starts occur. From my findings the main reason why most manufacturers are saying to not charge below 0°C is that they expect that you do not use "smart" BMS along with charging current control. So if you look at A123 Battery pack design guide you can find table with this derating.

For APR18650m1-A (1100mAh) continuous charging currents (not for cycle life):

65°C: 4A
30°C: 4A
25°C: 3.5A
15°C: 2A
10°C: 1A
0°C: 0.5A
-10°C: 0.3A
-20°C: 0.2A
-30°C: 0.05A

I ran two cycle life tests at -20°C with two APR18650m1-A samples. First test with setting 1C-1C (3.6V-2V) 100% DoD was ended with 76% of nominal capacity after 40cycles. Second test with 0.25C-1C (3.6V-2V) 100% DoD ends with 93% of nominal capacity after 40cycles.

Had plans at one point to "take the (energy) hit" and install Farnam nickel-chrome thin heating pads (w/very low watts) on the inside/bottom of my battery case:
https://endless-sphere.com/forums/viewtopic.php?f=35&t=19001

https://farnam-custom.com/custom/flexible-heaters

Silicone Rubber perhaps...


Of course, I'd also be insulating the battery compartment... Kinda partial to Aerogel.
https://en.wikipedia.org/wiki/Aerogel

Winston LiFeYPO4 Battery are supposed to be particularly resistant at low temp thanks to yttrium. I have no objective data to prove it though, just reading from their website

BU-410: Charging at High and Low Temperatures

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:
https://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures

Many battery users are unaware that consumer-grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the pack appears to be charging normally, plating of metallic lithium can occur on the anode during a sub-freezing charge. This is permanent and cannot be removed with cycling. Batteries with lithium plating are more vulnerable to failure if exposed to vibration or other stressful conditions. Advanced chargers (Cadex) prevent charging Li-ion below freezing.

Advancements are being made to charge Li-ion below freezing temperatures. Charging is indeed possible with most lithium-ion cells but only at very low currents. According to research papers, the allowable charge rate at –30°C (–22°F) is 0.02C. At this low current, the charge time would stretch to over 50 hours, a time that is deemed impractical. There are, however, specialty Li-ions that can charge down to –10°C (14°F) at a reduced rate.

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Hehe... "the charge time would stretch to over 50 hours"... MY fav "recharge rate" is to just swap batteries...

You need a 12V super-capacitor bank. It might bleed down over a month. And in that case, you might need a 6S LTO pack, or a 4S LiFePO4 pack to charge it up. That being said, I have seen a video of a super-cap bank on a car that had the lead-acid battery disconnected, along with the fuel relay. The SC bank spun the engine for about 20 seconds.

If you start the car at least once a week, you don't need a battery for the SC bank...

The only way around is unfortunately to build some kind of climate control system.
All batteries chemistries I know of are very sensitive to cold climate.

Where I live, we experience both relatively cold (around 0 degree C) and super hot (more than 40 degree C) weather conditions. I'm using A123 20Ah pouch cells and noticed quite a big performance drop once the temperatures got under 15 degree C.

So my plan is to build an Air conditioning system, which would be basically a well insulated battery box and a little peltier element controlled by an arduino. By reversing the polarity you can either warm up the battery when it is cold outside or keep the battery cool when it's too hot.
Peltier modules are not very efficient but this shouldn't matter too much provided I make a good job at insulating the battery and come up with a clever software to manage that. You can use the Peltier module at its full capacity when the bike is charging and then go to a power saving mode when the charger is not connected. The thermal mass of the battery itself should be enough to keep it in a safe zone for a while, depending on its size.

I'll post my experiements somewhere in the forum once I'll make enough progress and let you know

^^ That's "cool". Tks... or maybe "that's hot"... maybe both... not sure... :wink:

Anyway... Re any peltier elements... "Given that a Peltier cooler is probably around 15% efficient"... seen here:
https://electronics.stackexchange.com/questions/349224/optimize-peltier-element-cooling

NO idea what wire size the Farnam (heating) pads are... but suspect NiChrome better than 15%:
https://en.wikipedia.org/wiki/Nichrome

... and again... re battery case insulation check out Aerogel. :wink:

BTW... in this thread the OP notes "temperatures here as low as -40c occasionally, and there are typically several weeks each year where the daily high temperature is below -20c (approx 0f)"... so expect the "extreme climates" here are mostly about LOW temps. :wink:

LockH said:

Anyway... Re any peltier elements... "Given that a Peltier cooler is probably around 15% efficient"... seen here:
https://electronics.stackexchange.com/questions/349224/optimize-peltier-element-cooling

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Yep, they are highly inefficient, but good luck to cool anything with a Nichrome wire
If your only concern is to get the battery hot enough then, by all means, go for any kind of standard heating element it will inevitably be waaayyyy more efficient
The brain of the operation would essentially remains the same though, except you would need only one relay instead of two and you'd just have to get rid of the part of the code relevant to cooling.

But to be fair, I made a little test with a double Peltier module last week. The thing was drawing around 5 amps @ 12V, and got blazing hot in a few seconds. So that was something like 60 Watts, my guesstimation is that one hour will be enough to stabilize the temperature in the whole battery pack given the fact that this would be a pretty small space and I'dd have some little fans for air circulating. Then, after this, the Peltier module only has to work from time to time to maintain this temperature, which I think would be around 1/4 of the time or even less, depending how well the pack could be insulated, so basically 60/4= 15Wh or so.
My battery pack being around 3000Wh I think it leaves a fair margin to operate, I rarely let my motorbike unplugged more than 10 hours in a row anyway.

LockH said:

... and again... re battery case insulation check out Aerogel. :wink:

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Aerogel is extremely fragile from what I've heard, it would have to support the entire weight of the battery wobbling around on the messy roads, I don't think it would last more than 2 minutes. Plus I have no idea where to source that stuff, is it common in the US?
I'll just go with the good ol' trusty polyurethane foam, it's actually one of the best insulating materials, it's cheap, available everywhere and I can mold it and cut it easily.

^^ "but good luck to cool anything with a Nichrome wire"... :lol: Again, pretty sure this thread is about "too cold" ambient temps. :wink:

Re Aerogel... supplier:
http://www.cabotcorp.com/solutions/products-plus/aerogel

Yeah, maybe "pricey"... but one nice thing about "small EVs"... the parts/components are also small.

EDIT: How Aerogels Work
("Everyday Aerogel Uses"):
https://science.howstuffworks.com/aerogel4.htm

Been a while since I looked at this post, but somewhat unrelated to my original question, I decided to ditch my car's 12v battery when it passed away early this winter, and instead moved to a bank of supercapacitors and a LiFePO4 battery to extend standby time.










Setup is this, basically:

Mean Well HRP-600-12
6x Maxwell 3000F 2.7v caps, with balancing
4x 20Ah 3.2v LiFePO4 cells, with balancing
0.3ohm resistor w/heatsink, 40w rating
2 gauge braided copper to the fuse box and starter motor

High voltage 3 phase AC runs from brushless motor under the hood into the rear of the car. 3 phase AC goes to Schottky rectifier, passes on 70-300VDC to DC-DC converter. DC-DC is connected to supercapacitors via a high current relay, which only comes on when the car is running (to reduce parasitic draw), provides the (very efficiently generated, much better than an alternator) ~13.2VDC to run the car. Supercapacitors are for starting and running duty, highly efficient, are unaffected by cold - my car starts just as well when it's -20F (-30C) as on a warm summer day. Standby time with the caps is only around 3 days so I placed a LiFePO4 battery in parallel with the caps to increase standby time. Resistor is between battery and caps to prevent the lithium battery from taking much starting current and to keep charging current low when weather is cold.

Additionally, I added a thermostat-controlled a pair of 5w silicone rubber heating pads in series to the side of the battery. The battery could in theory self-heat, but for now I'm only running the battery heater from the DC-DC, and relying on insulation to keep the battery warmer, longer, between drives.

Overall it's good for a ~25lb weight reduction and should last far longer than a 12v lead acid in Vermont's climate.

Thoughts?

I've been wondering about this too. The super capacitors should be able to handle the extreme cold, but I am wondering about a battery to charge the caps.

If you start the car at least once a week, I'm fairly sure you wouldn't need a backup battery, but even if you do, the lithium battery wouldn't need to be large, or even high-amp.

I am curious if I could plug-in the lithium pack to the "cigarette lighter" 12V accessory socket to charge the capacitors, so I could keep the pack warm inside my home, and only take it out if the caps had bled down...

spinningmagnets said:

I've been wondering about this too. The super capacitors sho I led be able to handle the extreme cold, but I am wondering about a battery to charge the caps.

If you start the car at least once a week, I'm fairly sure you wouldn't need a backup battery, but even if you do, the lithium battery wouldn't need to be large, or even high-amp.

I am curious if I could plug-in the lithium pack to the "cigarette lighter" 12V accessory socket to charge the capacitors, so I could keep the pack warm inside my home, and only take it out if the caps had bled down...

Sent from my SM-S902L using Tapatalk

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I measured the parasitic draw in my car and figured that with the caps' natural self-discharge and the small current to keep the radio presets and other little bits going in the car, 6x3000F caps (which are equal to one higher voltage 500F cap when in series) will not quite last a weekend. That is to say, if you park the car on a Friday, it might not start Monday morning. If you were charging them a little higher (14.2v) you'd have a better chance, but 500F just isn't enough to handle the milliamp draw over a period of days.

I tested this in practice and found it to be true - I needed to jump start my car Monday morning as cranking was just a little too slow to get the engine going - that's when I added the lithium pack. 20Ah is overkill, of course, since it's behind a resistor and won't ever see starting current.

As for the cigarette lighter outlet, I drive a Japanese car and it's normal for the outlet to *not* be hot when the ignition is off, and it's increasingly common for that to be true in American cars too. To make this work I'd need to add another charge port which is connected directly to the caps. Not an issue, but also not exactly set-and-forget.

It shouldn't be difficult to set up a semiconductor relay. Get in the cold car that has been sitting for a week or two, flip the switch that connects the small Lithium pack to the supercapacitors, wait a couple minutes for the battery to charge the super-caps, then start the car.

Aside from poor cold-weather performance, lead-acid is actually appropriate for car-starting. However, it needs to be physically large to provide lots of plate surface area to provide lots of cold-cranking-amps (CCA). Once you add super capacitors to the equation, the 12V battery that charges them up can be very small.

I have seen the caps charged by a 18V cordless tool battery (5S, 20.5V when fully charged), with an auto-cutoff circuit at 14V. It only took a minute...Then the caps dumped the minutes worth of energy in 2 seconds to start.

spinningmagnets said:

It shouldn't be difficult to set up a semiconductor relay. Get in the cold car that has been sitting for a week or two, flip the switch that connects the small Lithium pack to the supercapacitors, wait a couple minutes for the battery to charge the super-caps, then start the car.

Aside from poor cold-weather performance, lead-acid is actually appropriate for car-starting. However, it needs to be physically large to provide lots of plate surface area to provide lots of cold-cranking-amps (CCA). Once you add super capacitors to the equation, the 12V battery that charges them up can be very small.

I have seen the caps charged by a 18V cordless tool battery (5S, 20.5V when fully charged), with an auto-cutoff circuit at 14V. It only took a minute...Then the caps dumped the minutes worth of energy in 2 seconds to start.

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Advantage of the system as I have it set up: Anyone can sit in the car, turn the key and drive away without having to know anything about the car. I also don't lose my radio presets if I leave the car sitting for more than a few days. If I were the only person who ever used my car I might consider having a battery pack I carry inside every night and/or a switch that I have to turn on 2-5 minutes before attempting to start the car.