【为什么手机电池耗得快?永恒电池可能吗?】

【为什么手机电池耗得快?永恒电池可能吗?】每次为电子设备充电时,都会浪费一定比例的能量,而且浪费能源的比例会随着时间的推移而增长,也称为“容量衰减”。也就是说,每次你急于插上你的智能手机充电时,实际上会让电池寿命变得更差。虽然研究人员不断让电池充电更快,持续时间更长,但他们不可能制造出真正永恒的电池。

Why does your phone battery die so quickly? One scientist explains why the amount of charge your device can hold will fade over time, and why we'll NEVER build an everlasting battery

  • Each time you recharge your electronic device, a percentage of energy is wasted
  • The proportion of wasted energy grows over time
  • As a result, older phone will not hold their charge for as long as newer models
  • This can leave people mistakenly believing their battery was always terrible, says Professor Steve Martin of Iowa State University

Many of us live in constant fear of our smartphone battery dying.

Although device manufacturers constantly claim to have improved battery life, it can often feel like your handset is always on the brink of dying.

This is likely a result of 'capacity fade', which means that each time you recharge the battery in your device a certain amount of energy is wasted.

The proportion of wasted energy grows each time you plug-in your device.

So, every time you rush to plug-in your smartphone to top-up the battery, you're actually making the battery life a tiny bit worse – compounding the feeling that it is always running out of juice. 

Although researchers are continually making batteries charge faster and last longer, it will be impossible for them to ever build a truly everlasting battery.

Writing for The Conversation, Professor Steve Martin from Iowa State University explains that no matter how hard engineers work, no battery will last forever.

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Although researchers are continuing to make batteries charge faster and last longer, it's impossible to make a truly everlasting battery (stock image)

Although researchers are continuing to make batteries charge faster and last longer, it's impossible to make a truly everlasting battery (stock image)

Why do batteries die? And, why can they only be recharged so many times before they won't hold a useful amount of charge?

My young son asked me about that years ago when his battery-powered toy car stopped moving, wondering about what he called an 'everlasting battery.'

And this same question has probably crossed the mind of every cellphone user trying to send one last text before the screen blinks off.

Research, like mine, continues around the world to make batteries that charge faster, last longer, and can be recharged and discharged many more times than today's.

But as much as you and I would like, it's impossible to make a truly everlasting battery. I have taught thermodynamics for more than 30 years. So far, there is nothing that suggests we can break the fundamental laws of science to get that elusive battery.

'Capacity fade' 

Battery scientists and engineers call the main problem 'capacity fade.' Regular people wonder about it with questions like 'Why won't my battery hold a charge?' and complaints like 'I just recharged this thing and it's already out again!'

It's a result of the second law of thermodynamics, which states that whenever some real process happens, it creates a certain amount of wasted energy along the way that can never be recovered.

Any time a battery is charged or discharged, there's a little bit of wasted energy – a little bit of wasted capacity in the battery that cannot be recovered.

The main problem is something called 'capacity fade' which basically means that whenever you charge your battery a certain amount of energy is wasted along the way (stock image)

The main problem is something called 'capacity fade' which basically means that whenever you charge your battery a certain amount of energy is wasted along the way (stock image)

To envision how this works, think about battery use like transferring water between two cups. Using a battery is like emptying the water from one cup into the other, and charging the battery involves pouring the water back into the first cup.

Even if you do it one or two times without spilling a drop, there's always just a little tiny bit left in each cup that you can't pour out.

Now imagine pouring back and forth hundreds or even thousands of times over a period of two or three years (for a cellphone battery) or 10 to 20 years (for an electric car).

Energy waste grows over time

Over time, all the thousands of little and big things that go wrong add up to quite a bit of water going missing. Even spilling a barely visible drop – say one-tenth of a millilitre – adds up to an entire litre if it happens 10,000 times.

That doesn't even include the possibility of one cup failing in some way that loses even more water – like springing a leak or heating up and causing evaporation.

Just as water inevitably goes missing when pouring from one cup to another, more energy is required to charge the battery than it actually stores, and less energy comes out than is stored in it. The proportion of wasted energy to stored energy grows over time.

In fact, the more you use a battery, the more energy gets wasted, and the sooner the battery will reach a point where it's dead and can't usefully be recharged.

I and others are studying ways to have those discharging-recharging cycles run more smoothly to reduce the amount of waste, but the second law of thermodynamics will always make sure that there's no way to get rid of it entirely.

Steve W. Martin is the Professor of Materials Science and Engineering, at Iowa State University.

This article was originally published in The Conversation

IS 'BACKGROUND REFRESH' TO BLAME FOR YOUR POOR IPHONE BATTERY LIFE?

Every time a new software update is issued, Apple users appear to have issues with battery life.

For instance, the latest iOS 11.4 update has caused to complain about battery problems.

One angry user wrote on Reddit that it caused their battery to drain up to 25% faster, while others say they are constantly having to charge their phone.

Apple has not yet revealed what is causing the problem or how to fix it.

However, some users suggest that the issue may be with the background app refresh feature.

This lets your apps run periodically in the background so that they can update their contents, even when you're not using your phone.

To lessen the affect on battery life, normal app background refreshing is scheduled for certain times, such as when your device is connected to Wi-Fi, plugged into a power source, or being actively used.

Forbes points out that affected users are primarily reporting that the issue happens at home.

This suggest that background synchronisation services could be to blame.

To turn off the feature, launch the Settings app from your Home screen and select General. Then switch Background Refresh to 'off'.

You can also toggle off the switches for each individual app.

原文链接:http://www.dailymail.co.uk/sciencetech/article-5990209/Scientist-explains-reason-smartphone-battery-fades-time.html


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