Whether you’re a snowboarder or a sun-seeker, chances are you’ve been on vacation and had your phone turn off because of battery temperature. On the beach, it gets too hot. On the slopes, it dies too quickly.
Either way, extreme temperatures are bad for any electronic device – batteries included. But is one worse than the other?
Heat is an obvious culprit for damage, and it’s definitely the fastest way to see your phone shut itself off. But leaving batteries in the cold has its own negative consequences.
Here’s why and how extreme temperature exposure affects battery life.
The chemicals inside batteries make them sensitive to temperature
Inside a lithium-ion or lithium-polymer battery are rectangular metal plates, surrounded by chemicals.
When voltage runs through those metal plates, it excites the electrons inside the battery – they start bouncing all over the place, having a little electron party. The interaction between the plates and the chemicals creates electrical energy, which is then stored inside the battery to power a device. (You can’t store actual electricity in a battery – just the energy.)
As you use the device, you deplete the battery’s saved electrical energy. The electron party dies down, and so does your phone.
When you add extreme weather to the mix, the dynamics change a bit. That’s because the chemicals dancing with the electrons are sensitive to temperature. So when it’s blazing hot or freezing cold, the chemicals get worn out more quickly than they do with regular use. They literally don’t have enough energy to party in extreme environments.
What happens in heat is different than what happens in cold
In extreme heat – like sitting on a beach or on a car’s sunny dashboard – a battery can overheat and ruin other components inside a phone or device. Electron movement creates its own warmth, so when you add an external source of heat like the sun, the party can get out of control. Your phone shuts it down and goes into self-preservation mode.
In extreme cold – like subzero Fahrenheit or sitting in your car overnight during winter – the electrons are too cold to get excited. Everything slows down, and the chemicals can’t hang as long as they usually would. Your battery dies faster, partly because it probably didn’t even reach its full-charge capacity.
So which is worse?
It’s not a straightforward comparison, but exposing a battery to extreme heat will damage it faster than leaving it in the cold. In some cases, keeping batteries in a cool (not freezing) environment is even thought to slow the rate of discharge, which is why it was common years ago for people to store alkaline batteries in their refrigerators.
Regardless, continued exposure to extreme heat and cold will decrease the life of the battery cells, just in different ways. So regulating battery temperature is the best thing you can do to extend its life.