Ok battery wizards, why not charge cold batteries?

[DrStupid]

What is the technical explanation for the warnings about charging below freezing?

For years we were told cold storage is best, even seen a youtube video with the Tesla engineer claiming he stores his lipos's in the freezer, or something to that effect.

I know about high currents being a problem when cold, but charging at a fraction of C certainly doesn't seem like it would qualify as high current.

Just looking to learn something, and the web doesn't seem to offer up an easy answer.

 

[TPEHAK]

I assume at freezing temperatures chargers do not get correct voltage feedback from the Lithium battery and can overcharge it or choose wrong charge rate and damage it.

Another theory is at low temperature charger will get low voltage feedback and will pump more energy in the battery causing local high temperature areas between electrodes in electrolyte in the battery cell while the battery is still generating not enough current because of most of the electrolyte is cold. But it is enough to overheat just small area between the electrodes to cause shortage in that area between the electrodes and kill the battery cell.

Yamaha batteries have battery management system protection which terminates charging process if battery temperature is too low or too hot, it forces the charger to wait until the battery temperature will be within the necessary limits.

 

[mopar04]

The metallic lithium will plate on the anode if charged in sub freezing temps. Once the lithium anode has become plated it becomes very prone to failure and it’s impossible to remove. It’s totally fine to discharge them in sub freezing temps though, or charge at an extremely low C-rate. But to be safe most good BMS modules have a low-temp charging cutoff set at around 2*C

 

[DrStupid]

The metallic lithium will plate on the anode if charged in sub freezing temps. Once the lithium anode has become plated it becomes very prone to failure and it’s impossible to remove. It’s totally fine to discharge them in sub freezing temps though, or charge at an extremely low C-rate. But to be safe most good BMS modules have a low-temp charging cutoff set at around 2*C

Does this plating occur during the entire process, or only as the battery reaches full charge? For example, if I limited the charging to 60% of the full charge state, would plating of the anode still be a problem if charging below freezing?

 

[mopar04]

Does this plating occur during the entire process, or only as the battery reaches full charge? For example, if I limited the charging to 60% of the full charge state, would plating of the anode still be a problem if charging below freezing?

It’s based on amount of current being applied to the lithium regardless of how full it’s currently charged. I think if you charge at something like .05C it avoids the plating occurring, but e-bike chargers and BMSs aren’t that accurate and most aren’t adjustable anyways. I have about 8,400Wh of lithium batteries on my toy hauler and can control my charge rates pretty accurately via software, but I wouldn’t risk it even with my trailers finely tunable setup.

 

[mopar04]

Does this plating occur during the entire process, or only as the battery reaches full charge? For example, if I limited the charging to 60% of the full charge state, would plating of the anode still be a problem if charging below freezing?

An easy fix is to get a small heating blanket for car batteries and wrap your bikes downtube (assuming that’s where your battery is) during charging. Just make sure to preheat the batteries prior plugging in the charger since the temperature inside the core of the cells is what needs to get to above freezing.

 

[DrStupid]

An easy fix is to get a small heating blanket for car batteries and wrap your bikes downtube (assuming that’s where your battery is) during charging. Just make sure to preheat the batteries prior plugging in the charger since the temperature inside the core of the cells is what’s needs to get to above freezing.

Thanks for the information. I will heed your advices.

 

[nasamorpheus]

my hybrid car is getting charged with ice engine at -30 degrees and no problems there

 

[mopar04]

my hybrid car is getting charged with ice engine at -30 degrees and no problems there

Hybrid/full electric car battery systems are self-heating and will preheat the cells before they allow a significant charge.