Why does my smartphone battery last less in winter?

Winter 2021 is coming across France and temperatures have already dropped dramatically. You may have noticed that the autonomy of your smartphone, too. You’re right, cold has many consequences for your phone.

Our smartphones are fragile little things. Not only physically with their screens and glass back, but also chemically in the composition of their batteries. Lithium-ion accumulators are actually very sensitive components to high heat and can damage our smartphone batteries in the event of a heat stroke.

But what about the cold exactly? Do our cell phones survive the winter better than us? Or should we put them on a little scarf, too?

« At elevated temperatures, there are irreversible reactions that significantly reduce the capacity of cells, commented Matthew Morcrete, a research engineer in solids chemistry at CNRS and director of the Laboratory for Reactivity and Solids Chemistry at the Jules Verne University of Picardie, in Nomirama. On the other hand, our low winter temperatures are excellent for avoiding side reactions. »

While hot weather can seriously damage our smartphone batteries, big cold waves don’t irreparably damage them. On the other hand, anyone who has used their smartphone in the midst of a frigid winter knows that battery performance can be quite damaged and missed. In particular, autonomy can be significantly reduced.

“The autonomy of our smartphones decreases with temperature”

« The temperature facilitates the diffusion of ions. On the contrary, lower temperatures slow it down. Thus the available capacity decreases with temperature […] So the independence of our smartphones in the cold too » Matthew Morcrete explains. If you have to charge your phone twice a day in the middle of winter, it’s partly because of the cold. But don’t panic.” This reduction is completely reversible ”, confirms the CNRS engineer.

Some users may have tried it, mid-winter smartphone battery gauge may be misleading. The OS might show a comfortable 40% charge just seconds before the phone shuts down, like running out of fuel. This does not mean that your battery ran out in the blink of an eye, but the physical phenomena themselves work.

For the battery to work, you need to pass ions from the positive electrode to the negative electrode. A bit like a battery, the power goes from less to more. The cold sometimes slows this chemical reaction so much that the phone can’t draw enough current to keep working. So it turns off, thinking the battery is empty. If I restart the phone when you are back inside, the battery will be at 40% again.

If your battery is already empty due to the cold, on the other hand, be careful with the charger you use to give it a boost. ” Li-ion batteries do not support fast charging well in cold weather, Matthew Morcrete Points. Lithium is difficult to diffuse and irreversible lithium loss phenomenon can be created. In short, if your battery is frozen, the ions will have a hard time getting back from the negative electrode to the positive electrode, as they do during the normal recharging phase, and they can somehow “get lost” and then damage your battery that way. Final.

« I advise against charging with fast chargers on a very cold smartphone », detail by Mathieu Morcrette. To return the juice to your phone, it is best to wait for it to warm up a little. But don’t panic again,”This phenomenon will only last for some time, because the battery will heat up very quickly. “To achieve an optimal operating temperature,” continues the engineer who interviewed Nomirama.

To answer the question simply: No winter will kill your smartphone. The effects of cold on batteries are annoying, but they do not damage the chemical composition of our batteries. If we pay a little attention to the way we use our phones in very cold weather, we don’t have to worry.

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