3 ms·

cold climates are better for batteries than hot.

by readhn 8y ago

nickelcitymario 8y ago
I really want that to be true, but try having your car battery die 3 times in a single week of -44 degree celsius (-47 fahrenheit) weather. Or, less dramatically, watch your phone go from 100% charged to 5% charged in just 30 minutes in that same temperature. I'm no physicist, but anecdotally, you are very very wrong. UPDATE: See hwillis' comment below. I'm so very very wrong, and am ashamed of my ignorance.
- hwillis 8y ago
  It is actually true. The battery stores just as much energy when it's cold, and has higher efficiency. The problem is that that efficiency drops dramatically as you try to pull more power. A very simplified explanation would be that the charge carriers have a harder time moving quickly through cold electrolyte. This results in a kind of drag (most of which is actually literal drag) that results in a lower voltage on the output. Your phone measures its charge via the voltage (partly), so when it starts pulling more power it suddenly registers much lower voltage. If you turned it off and let the voltage recover, it would show as charged again. Normal lead acid batteries will fail for the same reason; they can't push amps at low temperatures. If they were heated up they would work fine and they will have lost less charge than if they had been sitting at room temperature. Electric car batteries are the same, but the cold temperature enables to push much more power for longer without getting too hot. Please do not compare phone batteries to large, carefully controlled and well-treated batteries like those in new EVs. They are totally different animals. Phone batteries are probably the most brutal of all common battery applications; they are used as heat sinks, have zero temperature control, and regularly experience forces and temperatures that are way out of spec.
  - nickelcitymario 8y ago
    I retract my comment. This is absolutely fascinating. Thanks!
- Galaxeblaffer 8y ago
  Unless they made the battery protect itself from the cold with some kind of thermal management system ? Such a system could run in external power when plugged in, and as a safety be able to run on it's own power, draining the battery of course.
  - readhn 8y ago
    they already use this approach. batteries have its own thermal management system.
Gibbon1 8y ago
True. Range is reduced but the degradation is slower. Based on complaints it seems Nissan Leafs smaller batteries with crummy thermal management degrade fairly quickly in hot climates. But are 'fine' in mild climates.

cold climates are better for batteries than hot.

by readhn 8y ago

cold climates are better for batteries than hot.

I really want that to be true, but try having your car battery die 3 times in a single week of -44 degree celsius (-47 fahrenheit) weather. Or, less dramatically, watch your phone go from 100% charged to 5% charged in just 30 minutes in that same temperature. I'm no physicist, but anecdotally, you are very very wrong. UPDATE: See hwillis' comment below. I'm so very very wrong, and am ashamed of my ignorance.

hwillis 8y ago
It is actually true. The battery stores just as much energy when it's cold, and has higher efficiency. The problem is that that efficiency drops dramatically as you try to pull more power. A very simplified explanation would be that the charge carriers have a harder time moving quickly through cold electrolyte. This results in a kind of drag (most of which is actually literal drag) that results in a lower voltage on the output. Your phone measures its charge via the voltage (partly), so when it starts pulling more power it suddenly registers much lower voltage. If you turned it off and let the voltage recover, it would show as charged again. Normal lead acid batteries will fail for the same reason; they can't push amps at low temperatures. If they were heated up they would work fine and they will have lost less charge than if they had been sitting at room temperature. Electric car batteries are the same, but the cold temperature enables to push much more power for longer without getting too hot. Please do not compare phone batteries to large, carefully controlled and well-treated batteries like those in new EVs. They are totally different animals. Phone batteries are probably the most brutal of all common battery applications; they are used as heat sinks, have zero temperature control, and regularly experience forces and temperatures that are way out of spec.
- nickelcitymario 8y ago
  I retract my comment. This is absolutely fascinating. Thanks!
Galaxeblaffer 8y ago
Unless they made the battery protect itself from the cold with some kind of thermal management system ? Such a system could run in external power when plugged in, and as a safety be able to run on it's own power, draining the battery of course.
- readhn 8y ago
  they already use this approach. batteries have its own thermal management system.

Gibbon1 8y ago

True. Range is reduced but the degradation is slower. Based on complaints it seems Nissan Leafs smaller batteries with crummy thermal management degrade fairly quickly in hot climates. But are 'fine' in mild climates.