你的手机没坏,只是冷了

每年冬天,这样的事几乎人人都会遇到。你在寒冷的户外,掏出手机查地图,屏幕却突然黑了,尽管几分钟前它还显示百分之四十的电量。难道电池一直在骗你?从某种意义上说,是的。

It happens to almost everyone at some point each winter. You are out in the cold, you pull out your phone to check a map, and the screen goes dark, even though it showed forty percent battery only moments earlier. Had the battery been lying to you? In a sense, yes.

每部手机里都有一块锂电池,与其说它是一罐储存好的电力,不如说是一场持续进行的小型化学反应。电力的产生,靠的是粒子在电池两极之间的迁移,而和大多数化学过程一样,一旦温度下降,这种迁移就会明显变慢。在寒冷的空气中,粒子移动得太迟缓,电池无法快速输出电力,电压骤然下降,手机把这种下降误读为电量耗尽,于是自动关机,以保护内部电路。

Inside every phone sits a lithium battery, which is less a tank of stored electricity than a small, ongoing chemical reaction. Power is generated as particles migrate between the two sides of the battery, and like most chemical processes, that migration slows down considerably once the temperature drops. In freezing air, the particles move so sluggishly that the battery cannot deliver power quickly enough, its voltage collapses, and the phone, reading that drop as an empty battery, switches itself off to protect its circuits.

证据在你回到室内的那一刻就出现了。化学反应重新变暖、加快,同一部手机重新开机,显示的电量或许是百分之三十,仿佛什么都没发生过。电力其实一直都在,只是被一场迟缓的反应困住了。这就是为什么在冬天,最好把手机放在贴身的内袋里,靠近你自己的体温:电池其实并不弱,它只是对你所处的天气不太热情。原来,一直缺的不是电量,而是温度。

The proof arrives the moment you step back indoors. The chemistry warms up, speeds up, and the very same phone switches back on showing perhaps thirty percent, as though nothing had happened at all. The energy had been there the whole time, merely trapped behind a sluggish reaction. Which is why, in winter, it pays to keep your phone in an inner pocket, close to your own body heat: the battery is not actually weak, it is simply unenthusiastic about your weather. Warmth, not charge, was the missing ingredient all along.