Explosions aren’t the only problem the batteries in smartphones. In countries where the winter takes place at a temperature below 0°C, the gadget in the cold may run out at any moment. In the edition of Hi-Tech Mail decided to find out why this is happening.
The battery is a weak spot of modern mobile devices. They drain quickly, heat up during fast charging, the experience of the Samsung Galaxy Note 7 shows that the phones may even explode due to the battery. But the Russians are now worried another problem — the iPhone and other smartphones tend to drain quickly in the cold.
Why does the phone freeze
Production technology sources of energy varies much more slowly than other industries. In 1991 withdrew the first mobile phone with a battery with a lithium anode, which exploded during a call. Then the producers switched to energy sources with the electrolyte of the lithium to increase the security.
During charging, lithium ions are introduced into the crystal lattice of the carbon material, most often graphite, the cathode (negative electrode) and moves back to the anode (positive electrode) during discharge. The cold can disrupt this process.
The low temperature slows down all the process: the meat in the freezer will be preserved better than in the refrigerator — bacteria are less active. Same with the battery, but instead of microorganisms it “work” lithium ions.
The cheaper the better
Aluminum has high thermal conductivity (average of 220 W/(m·K)) is both a plus and a minus for a smartphone. Gadget better heat dissipation from the battery and CPU, but a faster “frozen”. The thickness of the device also plays the role of the battery in the slim smartphone will quickly become unstable.
iPhone is a clear example of this. Most of the exterior of Apple’s smartphone is made of aluminum, and the thickness of the iPhone 6/6s/7 — 7.1 mm. the Study showed that the temperature of -15°C is contraindicated in iPhone 6. The manufacturer knows this and warns that the range of ambient temperatures for iOS devices is from 0°to 35 ° C.
Glass conducts heat worse than metal — a total of 1.15 W/(m·K), but it’s enough to phone quickly “froze” in the cold. Samsung Galaxy S7 is covered with glass on two sides, but the side frame is made of aluminum. The manufacturer has set it exactly the same recommendations operating conditions 0 to 35 °C.
For “survival” in the cold lead plastic, its thermal conductivity is around 0,15-0,20 W/(m·K), depending on type. An “old” Samsung Galaxy SII turns off only when the temperature of -35°C, and a “dialer” Nokia C1-01 at -40°C!
Manufacturers of modern smartphones is not recommended to use them in freezing temperatures (below zero). This is partly the fault of the materials — aluminium and glass. In the budget phone case is made from a simple PVC or polycarbonate plastic kinds. Therefore, in the conditions of the Russian winter the rule — the cheaper the better.
The composition of the battery has a value
Artem Anisimov, the service technician Re-Mobile noted that lithium-containing batteries don’t like freezing, so long to use them in the cold is not desirable. However, there is a difference between lithium-ion and lithium-polymer options.
“Li-polymer sensitivity to cold, of course, below. The temperature range they have — approximately from -20 to 35 degrees Celsius. Li-ion batteries also could be in trouble already at a temperature below zero. All because the chemistry of lithium-ion batteries are more sensitive to temperature loading. And there the temperature range is another: about 2 to 25 degrees. However, despite this, lithium-polymer batteries are less common. They are more expensive,” says Anisimov.
So, a smartphone with lithium polymer battery, better tolerate the cold.
To solve the problem easily — warm smartphone:
- Put the cover, then the cold will be slower to enter the battery;
- Store the phone in an inner pocket, close to the body;
- Don’t hold your gadget in the cold longer than 10 minutes;
- Warms the smartphone gradually — from the sudden drop in temperature in the enclosure, condensation may form;
- Do not charge the phone in extreme cold — so it is possible to harm the device.
If you are not able to save the battery from the cold and your iPhone becomes disconnected, keep him warm: a jacket pocket, in your purse, in the car, etc. Already after 5 minutes, the gadget will become “alive”. Also for conditions of the Russian winter it is necessary to consider that the larger the volume of the battery in the smartphone, the slower it will “freeze”.