Charging below freezing

I've come to learn that charging Lithium Ion Batteries below 32F can cause lithium plating to occur. The LEAF's battery temp gauge at 4 bars goes from below freezing to above freezing, not a lot of help.

The user manual simply states that charging will take longer below freezing.

Does anyone know how the LEAF has been engineered with regard to below freezing charging and if they have found a way to mitigate the plating risk?

Probably not a good idea in general to let the battery temp fall much below zero. Keep in mind charging will usually generate enough heat to keep the pack from getting that cold anyway. I think if I was going to park my Leaf unused in a below freezing environment, I would be sure the pack was ran down enough, then perform 120v charging to keep the pack slightly warm while stretching the charging out. Then turn on the leaf and use the CC to run it down again, lather, rinse, repeat. They fixed this problem with the cold weather package. If you had this, you could just leave it plugged in on 120v.

If I was to move to a really cold area and had a 2011 w/o cold-weather, and I was forced to keep it exposed, I would add in a battery heating system. Maybe rip apart the heating wire out of an electric blanket and route throughout the pack. It wouldn't take much unless you were in Siberia or something. If I found myself there, the least of my concerns would be maintaining an EV! :shock:

-Phil

Phil,

When you say "zero" are you saying "zero F" or "zero C"?

Thanks.

And, does anyone know about this plating issue referred to in the original post?

Twiggy said:

Phil,

When you say "zero" are you saying "zero F" or "zero C"?

Thanks.

And, does anyone know about this plating issue referred to in the original post?

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My belief is that it is concern at zero centigrade, 32f.


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

I believe it is at or around 32F. Lower temperature means lower capacity to carry current. As I understand it, it's the same damage that occurs with overvoltage. Lithium ions cake onto the anode because they can't flow between the layers of the anode, and it causes permanent damage.

I may be wrong, but charging seems to warm the battery nicely (so does driving). Since my car is charging overnight and throughout the day in the winter (due to the huge impact on range), I don't think this will be a major issue.

I've had my LEAF for almost 2 weeks in TN & I've only seen 4 bars on battery temp twice. Both times it was a little below 30deg & had been a while since charged. I charge under my carport with L2. It's set to 100% most mornings at 7:00am with pre-heat cabin ending at 7:20, then I leave for work.

I've only seen 6 bars on battery once, when I've hit the DCQC after running on the interstate when it was in the 70s last week.

Seems like if there was battery damage from cold, the Chicago people would be shouting by now.

Philip

philipscoggins said:

Seems like if there was battery damage from cold, the Chicago people would be shouting by now.

Philip

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Judging by Phil's response, it seems prudent to plug-in and charge directly after stopping the vehicle when the temp is below freezing outside.

My routine in the summer is to leave the car at least 30 minutes before plugging in after getting home. In the winter I won't wait.

That's just great. Now I have to worry about permanent battery reduction issues in the cold. It was 8 degrees F yesterday morning here. Maybe I need to charge at 120 this winter overnight instead of 240 to prevent permanent battery degradation, per the Battery U link from the previous poster. I have the cold weather package, and it the battery warmer should have kicked on at 14 degrees F, but our garage probably did not get that cold. How would I know that the battery warmer is on? Are there any icons on the dash or carwings (yeah, right ), or additional load on the charging circuit? I will keep an eye on it tonight--It is supposed to be cold again.

philipscoggins said:

I've had my LEAF for almost 2 weeks in TN & I've only seen 4 bars on battery temp twice. Both times it was a little below 30deg & had been a while since charged. I charge under my carport with L2. It's set to 100% most mornings at 7:00am with pre-heat cabin ending at 7:20, then I leave for work.

I've only seen 6 bars on battery once, when I've hit the DCQC after running on the interstate when it was in the 70s last week.

Seems like if there was battery damage from cold, the Chicago people would be shouting by now.

Philip

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how long has Chicago had a LEAF. has it even been one complete winter?

Rauv said:

That's just great. Now I have to worry about permanent battery reduction issues in the cold. It was 8 degrees F yesterday morning here. Maybe I need to charge at 120 this winter overnight instead of 240 to prevent permanent battery degradation, per the Battery U link from the previous poster. I have the cold weather package, and it the battery warmer should have kicked on at 14 degrees F, but our garage probably did not get that cold. How would I know that the battery warmer is on? Are there any icons on the dash or carwings (yeah, right ), or additional load on the charging circuit? I will keep an eye on it tonight--It is supposed to be cold again.

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if you are in the garage, you will be fine. In most places, even cold ones, your garage temp is unlikely to go below 0 º C. i would put a thermometer out there to get an idea of where you are at) I am in my 3rd winter and 25,000 miles and just now seeing undisputable signs of degradation which is better than I had expected or planned for when making the decision to LEAF it.

A LOT of places, even in garages, get substantially colder than
32 degrees F during the night, and even during the day.

The Nissan cold weather package does nothing at freezing
temperatures, it only turns on when the battery gets down
below 0°F, as I recall.

So, apparently Nissan is not at all concerned about
any battery damage at the temperatures around freezing.
One would hope that Nissan would know.

Here is a reference (J. Fan and S. Tan, "Studies on Charging Lithium-Ion Cells at Low Temperatures," Journal Electrochem. Soc., Vol 153, A1081 (2006)) to a research paper on charging 18650 cells (LiCoo2 positive electrode, graphitized carbon, like MCMB25-28) at low temp. (-20C, -4F). Two comments from the paper: (1) Li-ion cells can deliver up to 90% of rated capacity at -20C and at 0.2 C rate, while it is impossible to put 90% capacity into the cell at -20C and 0.2 C rate without Li plating. (2) It appears that the Li solid diffusion in the graphite negative is the ultimate rate-limiting factor for charging Li-ion cells at low temp.

Since Li plating occurs on the graphite electrode during low temp. charging, a similar problem should be present in Mn-based cells that have graphite negative electrodes. At 0C (32F), Li plating should be less of a problem, but that is not to say there isn't some potential deleterious effect on the cell, which may be a function of the cell chemistry (for example, electrolyte composition, electrode materials). An electrolyte such as 1M LiPF6/EC:EMC is not completely frozen at -50C, so assuming the electrolyte in the LEAF battery does not freeze at a similar temp., then 0C (32F) should be within the acceptable charging range, but at a slower rate. IMO.

Some applicable info here. Apparently, after cold soaking outside overnight with a low of 22F, when plugged in early the next morning, the BMS heated the battery via TMS for an hour before charging started. Another owner had issues to get charging to start ... with the TMS attempting to pre-heat the battery at -7F.

DaveinOlyWA said:

if you are in the garage, you will be fine. In most places, even cold ones, your garage temp is unlikely to go below 0 º C. i would put a thermometer out there to get an idea of where you are at) I am in my 3rd winter and 25,000 miles and just now seeing indisputable signs of degradation which is better than I had expected or planned for when making the decision to LEAF it.

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I agree with that. This morning it was 27 outside but 43 in my garage. When it gets into single digits is when my garage may drop below freezing which is just a few days or weeks of the year here in TN.

Glad your LEAF is holding up, I'm at 18,000 miles and this is my second winter. So far so good here with moderate indications of degradation.

Rauv said:

That's just great. Now I have to worry about permanent battery reduction issues in the cold. It was 8 degrees F yesterday morning here.

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Overnight lows are not an issue, you can drive in cold temps without issues. If you charge shortly after driving home hopefully the battery temp is just fine for charging. My issue is that I don't know the battery temp thanks to the temp gauge being so imprecise. Even a 'snowflake' symbol on the dash to indicate a freezing battery would be all we need to take precautions.

already posted this in the GID increase in CW thread but my GID count has dropped from average 280 to 272 all in the past 2 weeks.

Right now I am parking LEAF outside and that should continue thru the holidays. overnight lows generally in mid to upper 30's but have had a few nights into the 20's. wondering if that is reason i received sudden drop in SOC?

but then again, I felt I had lost around 5% capacity during the Summer despite the 280-281 GID readings, so thinking this might be just an adjustment to the GID value?

as always will continue to monitor

Twiggy said:

Phil,

When you say "zero" are you saying "zero F" or "zero C"?

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Zero C or 32 F.

-Phil

DaveinOlyWA said:

philipscoggins said:

I've had my LEAF for almost 2 weeks in TN & I've only seen 4 bars on battery temp twice. Both times it was a little below 30deg & had been a while since charged. I charge under my carport with L2. It's set to 100% most mornings at 7:00am with pre-heat cabin ending at 7:20, then I leave for work.

I've only seen 6 bars on battery once, when I've hit the DCQC after running on the interstate when it was in the 70s last week.

Seems like if there was battery damage from cold, the Chicago people would be shouting by now.

Philip

Click to expand...

how long has Chicago had a LEAF. has it even been one complete winter?

Click to expand...

Hey, it gets much colder north of us (ever hear of International Falls, MN typically has the lowest recorded temps in the U.S.?) and the earliest LEAF's delivered around here are now just coming up on a year old (all with CWP in '11's as dealer demo's or '12's delivered to customers), we had a relatively mild winter last year and I myself have a semi-heated garage anyways. I do see the temp bars down to 4 but only when it sits out all day in the cold, overnight in the A.M. its typically at 5 bars after charging in about a 60 F garage temp.

Here's the confusing chart from the service manual:


-Phil

Ingineer said:

Here's the confusing chart from the service manual:

-Phil

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Interesting that they don't show anything below 80% deterioration. The battery is meant to reach EOL at 70% right?