为什么手机在寒冷中会没电

每年冬天都会发生这样的事。你在寒冷的户外，拿出手机想看地图，结果它没电关机了。可是一分钟前，电量还显示百分之四十。是电池在骗你吗？在某种意义上，是的。

It happens every winter. You are outside in the cold, you take out your phone to check the map, and it dies. A minute ago it showed forty percent. Was the battery lying? In a way, yes.

手机里装着一块锂电池，而电池并不是一个装满电的容器，它更像一个小型化学工厂。电力是由粒子在电池两端之间移动产生的，而和大多数化学反应一样，这种移动在低温下会变慢。在寒冷的空气中，粒子移动得太慢，电池无法输出足够的电力，电压随之下降。手机检测到电压过低，判断电池已经耗尽，于是自动关机，以保护自己。

Inside your phone is a lithium battery, and a battery is not a tank of electricity. It is a small chemical factory. Power is made by particles moving between two sides of the battery, and like most chemistry, that movement slows down when it gets cold. In freezing air, the particles move so slowly that the battery cannot push out enough power, and its voltage drops. The phone sees the low voltage, decides the battery must be empty, and switches off to protect itself.

证据随后就会出现。你走进温暖的房间，化学反应重新活跃起来，同一部手机又开机了，显示还有百分之三十的电量，仿佛什么都没发生过。电量其实一直都在，只是被缓慢的反应冻住了。所以在冬天，把手机放在贴身的内侧口袋里，靠体温保暖。电池并不弱，它只是不喜欢你所在的天气。

The proof comes later. You step into a warm room, the chemistry wakes up, and the same phone turns on with thirty percent battery, as if nothing happened. The energy was there all along, just frozen behind a slow reaction. So in winter, keep your phone in an inside pocket, close to your body heat. The battery is not weak. It is simply not a fan of your weather.