如果你在戶外遭遇了極地渦旋，即讓北美瑟瑟發(fā)抖的北極氣團(tuán)——但愿不要如此！——你的手機(jī)可能會(huì)有奇怪的表現(xiàn)。沒錯(cuò)，你會(huì)發(fā)現(xiàn)手機(jī)的續(xù)航時(shí)間受到了影響。一不小心，電量就可能在不發(fā)出警報(bào)的情況下從30%猛然跌到……好吧，0%。

是的，寒冷天氣會(huì)降低手機(jī)電池的性能。盡管這一點(diǎn)似乎不可思議，不過耗電飛快的原因很簡單。以下是這一現(xiàn)象背后的科學(xué)道理，以及讓你的設(shè)備持續(xù)工作的一些小建議，它們大多都是常識(shí)。

又冷又酷的科學(xué)知識(shí)

簡單來說，低溫天氣下手機(jī)電池續(xù)航降低是由于化學(xué)原因。

包括手機(jī)、筆記本電腦、電動(dòng)汽車在內(nèi)的大部分現(xiàn)代消費(fèi)品，它們的可充電電池都采用了鋰離子技術(shù)。在這些電池系統(tǒng)里，電流會(huì)從通常由石墨制成的陽極流向金屬氧化物制成的陰極。而兩極之間的電解質(zhì)，通常是含鹽液體或膠體，則用于導(dǎo)電。

一般情況下，帶電粒子會(huì)在兩極之間無縫流動(dòng)，產(chǎn)生電流和能量。不過低溫會(huì)讓情況變得更加復(fù)雜。將液體放在冷凍庫中，它會(huì)結(jié)凍，電池芯中的情況也是類似。

加拿大滑鐵盧大學(xué)（University of Waterloo）的化學(xué)教授琳達(dá)·納扎爾表示，低溫會(huì)導(dǎo)致電解質(zhì)變濃，粘性增加。材質(zhì)的導(dǎo)電性會(huì)隨之減弱，降低了推動(dòng)電池中化學(xué)引擎的帶電粒子的移動(dòng)性。

納扎爾說道：“電池是根據(jù)電化學(xué)的規(guī)律工作的，氣溫降低，反應(yīng)就會(huì)變慢。這只是自然規(guī)律導(dǎo)致的結(jié)果。”

科技公司怎么說

大部分大型手機(jī)廠商都向消費(fèi)者發(fā)出了警告，稱嚴(yán)寒天氣可能會(huì)影響公司的產(chǎn)品性能。

iPhone的制造商蘋果（Apple）表示，寒冷氣溫下電池續(xù)航時(shí)間會(huì)有所減少，不過也指出“這種情況是暫時(shí)的”。公司在官網(wǎng)上保證：“一旦電池的溫度回到正常工作溫度，性能也會(huì)回歸正常。”

按照蘋果所述，“理想的舒適區(qū)”是62華氏度至72華氏度。不過根據(jù)蘋果提供的下圖顯示，只要?dú)鉁卦谒谋c(diǎn)之上，iPhone的性能應(yīng)該就不會(huì)受到影響。

If you’re caught outside—heaven forbid!—in polar vortex, an Arctic air spillover numbing North America, your phone might act peculiar. Indeed, you may notice the battery life of your handset take a hit. If you’re not careful, the charge could drop precipitously, without warning, from 30% to…well, zero.

It’s true: Cold weather worsens the performance of phone batteries. While this may seem mysterious, there’s a simple reason for the juice-sapping affliction. Here’s what’s behind the phenomenon and a few tips, mostly common sense, for keeping your devices alive.

Cool science

Put simply, phone batteries worsen in the cold because of chemistry.

The rechargeable batteries in most modern consumer products, including cellphones, laptops, and electric vehicles, use Lithium ion technology. In these systems, an electrical current flows from a positively charged anode, typically made of graphite, to a negatively charged cathode, a metal oxide. In between, an electrolyte, usually a salty liquid or gel, conducts electricity.

Under normal conditions, charged particles flow seamlessly between opposing nodes, creating an electric current and source of power. But cold temperatures complicate the situation. Put a liquid in a freezer and it will freeze; a similar principle is at work inside a battery cell.

Cooling causes the electrolytic medium to thicken and become more viscous, explains Linda Nazar, a chemistry professor at the University of Waterloo in Canada. This makes the material a poorer conductor, reducing the mobility of the charged particles that drive the battery’s chemical engine.

“Batteries work on electrochemistry and those processes get slow when the temperature drops,” Nazar says. “That’s just a consequence of the laws of nature.”

What tech companies say

Most major phone-makers alert customers that frigid environments will affect their products’ performance.

Apple, maker of the iPhone, says that battery life decreases in colder temperatures, but notes that “this condition is temporary.” As the company’s website reassures, “Once the battery’s temperature returns to its normal operating range, its performance will return to normal as well,”

The “ideal comfort zone,” as Apple puts it, ranges from 62° Fahrenheit to 72°F. But iPhones should remain unaffected as long as they’re kept above the freezing point of water, as the Apple graphic below advises.

另一方面，蘋果警告稱，高溫可能“對(duì)電池容量造成永久損害”。換句話說，把手機(jī)放到高溫下炙烤，電池的蓄電量將永久減少。

與此同時(shí)，三星公司（Samsung）在設(shè)法打消某些消費(fèi)者堅(jiān)信的“常見謠言”：電池在冷凍冰箱中儲(chǔ)存，能夠工作更長時(shí)間。公司特別指出不建議這樣做，并警告稱這是“錯(cuò)誤的做法，可能損壞你的電池”。

永遠(yuǎn)做好準(zhǔn)備

現(xiàn)在你知道了氣溫和電池性能背后的科學(xué)道理，接下來我們提供了一些建議。這里重申，沒錯(cuò)，它們大多都是常識(shí)。

——讓你的手機(jī)在合適溫度下工作。（例如，三星公司就建議在酷暑或酷寒天氣把手機(jī)放在汽車的儲(chǔ)物箱中。）

——帶上便攜式充電寶。它們既便宜，又能在關(guān)鍵時(shí)刻派上用場。

現(xiàn)在在那里穿暖一點(diǎn)吧！（財(cái)富中文網(wǎng)）

譯者：嚴(yán)匡正

Screenshot from Apple’s website

On the other end of the spectrum, hot temperatures can “permanently damage battery capacity,” Apple warns. In other words, cook your phone and a charge will forever carry less juice.

Samsung seeks, meanwhile, to dispel what it calls a “common myth” persisting among some consumers: that batteries last longer if stored in a freezer. The company specifically advises against this practice, warning that it “is not correct and can damage your battery.”

Always be prepared

Now that you understand the science behind temperature and battery performance, here are our tips for you. To reiterate, yes, they’re mostly common sense.

—Keep your phone within the right temperature range. (Samsung, for instance, advises against stashing phones in the glove compartments of cars on very hot or cold days.)

—Bring a portable, external battery pack with you. They’re cheap, and they can come in handy in a pinch.

Now bundle up out there!