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Batteries In Gadgets Can't Support Gee-Whiz Adds
2007年07月23日16:30
That new phone or music player or notebook computer of yours: You like it so much you wish you could play with it all day. If only its battery would let you.
Most consumers now realize what engineers have known for ages: Batteries aren't keeping up with the rest of electronics. Unfortunately, say the experts, not only are things unlikely to change anytime soon, they may get worse before they get better. Thanks to shrinking computer chips, the consumer-electronics industry has gotten to the point where it is adding features to products much more quickly than the battery industry can accommodate.
The famous Moore's Law has computer chips doubling in capacity every two years or so. The progress for batteries is more in the neighborhood of 10% a year, says Lawrence H. Dubois, who heads up physical-sciences research at SRI International, the Menlo Park, Calif., research outfit. Improvements, he said, tend to be incremental, even 'mundane,' like figuring out a thinner container for batteries and thus saving space.
Not surprising, device manufacturers regard every advance in batteries as something of a gift from heaven. 'With even 20% more efficiency, you could make the phone slimmer or the display bigger and brighter,' said Muzib Khan, a Samsung vice president working with mobile phones. 'It opens up more opportunities.'
The problem is that the basic design of batteries hasn't changed -- and really can't. One part gives up electrons for energy, one part accepts them and a third part keeps the two separated. Researchers scout for new materials that will provide the most chemical energy in the least weight and space; lithium-ion batteries, used in consumer electronics for the past 10 years, is the best anyone has come up with.
Because they have to work with the periodic table that nature gave them, 'there are just so many ways of putting materials together,' said Robert G. Visser, who heads up the business unit at 3M that supplies raw ingredients to lithium-ion battery makers. The big manufacturers include Sony, Panasonic, LG and Sanyo.
With progress so slow, consumer-electronics companies say that energy awareness is pervasive in the design process, as they bring out new, portable gadgets.
After Apple announced its new iPhone in January, for example, its engineers went to work looking for places in the device's software that could be tweaked to cut back battery usage, said Greg Joswiak, an Apple vice president who handles iPhone marketing. The result was a boost in the talk time of the device.
From the beginning, said Mr. Joswiak, design decisions were made with the battery in mind. Apple picked the video-playing software programs known as codecs because they used the least power. The company was criticized for not including a pop-out battery with the iPhone, but Apple replied that the doors and latches for a replaceable battery would have taken up too much room.
Though breakthroughs in performance may not be in the cards, battery makers and their scores of suppliers are working on smaller advances. For example, efforts are under way to engineer lithium batteries so they generate less heat. Excessive heat build-up led to the battery fires that forced Sony's massive and expensive battery recall last year.
The next big advance in gadget power was supposed to have been provided by fuel cells. This technology, though, is proving very difficult to bring to market.
Fuel cells contain a reservoir of a fuel source, akin to a gas tank in a car. While hydrogen gas is often mentioned for use in automotive fuel cells, liquid methanol is considered ideal for smaller consumer devices. When the fuel source is depleted, you recharge by simply filling it up again, much like you'd refill a reusable cigarette lighter.
With boosters claiming that a fuel source like methanol has 10 times the energy potential of lithium ion, fuel cells have received an enormous amount of attention. But the result, says John Turner, of the National Renewable Energy Laboratory in Golden, Colo., has been 'overzealous selling of the concept, one that is unconnected to the reality of the technology.'
Mr. Turner said fuel cells are proving much more difficult to manufacture than had first been envisioned, largely because they are complex devices, containing small, precise parts, such as pumps.
Considering all the fuel-cell hype, the most respected fuel-cell companies are careful not to oversell what they are doing. For example, PolyFuel, of Mountain View, Calif., a spinoff of SRI, has a methanol fuel cell that it expects to be in the market in the next year or two. President Jim Balcom says the first iterations of the product will provide the same energy as lithium ion, but with half the weight and slightly less space.
Mr. Balcom says he doesn't expect fuel cells to replace lithium ion any time soon, but rather to remain a niche technology aimed at customers willing to pay slightly more for longer usage time.
With their constantly improving performance and declining prices, computer electronics have long seemed as close as the world could come to a free lunch. Batteries remind us the rest of the world isn't like that.
Lee Gomes
From Wallstreet Journal
Fortunately, a lot of companies have already gained achievement in this field, such like the world famous ACEVER brand emergency batteries. |
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A battery is an electrochemical cell (or enclosed and protected material) that can be charged electrically to provide a static potential for power or released electrical charge when needed.
A battery generally consists of an anode, a cathode, and an electrolyte.
Common types of commercial batteries and some of their characteristics and advantages are summarized in the following table. Battery types not shown include the Zinc-Air, Flooded Lead Acid, and Alkaline batteries.
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Battery Type
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Characteristics
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Typical Uses
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Advantages
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Sealed Lead Acid (SLA) battery
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Can hold a charge for up to 3 years
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Backup emergency power source
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Inexpensive
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Nickel-Cadmium (Ni-Cd) battery
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Fast, even energy discharge
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Appliances, audio and video equipment, toys; most popular batter
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Relatively inexpensive; widely available
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Nickel-Metal Hydride (Ni-MH) battery
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Typical power capacity i1.2 V - 1200 to 1500 mAh; extended life 2300 mAh; 2.5 to 4 hours battery life
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Portable computers; cellular phones; same as for Ni-Cd batteries
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No memory effect; unused capacity remains usable
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Lithium Ion (Li-Ion) battery
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Stable and safe; highest energy capacity
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Portable computers; cellular phones; same as for Ni-Cd batteries
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Twice the charge capacity of Ni-Cd; slow self-discharge
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The Battery Is Your Laptop's Weak Link
2007年10月19日14:46
We talk about being mobile, part of a wireless world, untethered (OK, it's just me who says 'untethered'). But if, midflight and midsentence, you've ever cursed your laptop battery for giving out, or developed the habit, when you walk into Starbucks, of immediately peering under chairs and through people's legs for a power outlet, you'll know that the reality doesn't quite match the talk. Our laptops might be more portable than before, our connections might be faster and involve less cabling, but we know our batteries will let us down. We still need juice.
Of course, there are some people who never seem to need an outlet. At one conference, I offered a slot in a power strip I had managed to purloin to a fellow journalist, only for him to turn it down, snootily proclaiming he was using a Mac and therefore didn't need power (personally, I don't agree with his view that Macs have longer-lasting batteries; I suspect he just had a newer battery than mine). And some people, who always seem to be ridiculously good-looking, sit in Starbucks all day in front of laptops without any visible wires (I suspect their laptops are turned off). But what can the rest of us do to make the most of our batteries?
The truth is: not an awful lot. 'I watch the consumer becoming more and more agitated,' says Christina Lampe-Onnerud, founder and chief executive of U.S. battery-technology company Boston-Power Inc. 'My message is very simple: There's very little you can do.' Of course, Ms. Lampe-Onnerud has an ax to grind: Her company is working with heavyweights like Hewlett-Packard Co. to launch a new kind of battery called Sonata, which she says will have a lifespan as long as that of your laptop and give you at least four hours of power between charges, compared with two to three hours with existing batteries. (She declined to say when they'd be available and how much they'd cost.)
Truth is, there's a lot of smoke and mirrors about batteries. Computer companies offer plenty of advice about how to get the most from yours, but it's probably wise to keep your expectations low. Battery technology still relies on chemical reactions taking place inside those innocent-looking slabs of plastic, and improvements happen, according to Isidor Buchmann, founder and chief executive of Canadian battery-charger maker Cadex Electronics Inc., far more slowly than improvements in, for example, chip speed.
So assume your battery is a dying beast as soon as you buy it. It only has a few hundred cycles -- from charged to empty -- before it starts to resemble a very expensive doorstop. The trick is to slow the dying process. To do this, it's best to think of your battery as separate from your laptop. Yes, it fits snugly underneath it, but that doesn't mean it should live there.
When you buy a new laptop or a new battery, go through at least one cycle of charging it fully and then discharging it, and do the same again every few months. This will reset the digital circuit that estimates the battery's charging status, so it doesn't stop charging prematurely. Resetting the gauge, says Atsushi Kumaki, director of ThinkVantage Technologies at Lenovo-Group Ltd.-owned Yamato Labs in Tokyo, 'will gain you a few percent' of charge each time.
Then plan your day. If you know you're going to use the battery, charge it fully beforehand. If you're not going to need it, let the battery run down until it's just under half full and remove it from your laptop. (Of course, this means you no longer have a battery backup if power fails, so if you're vulnerable to power outages or colleagues yanking out the power cord with their legs, you might not want to do this.) Laptop batteries should be stored at about 40% full; fully charged, they're a fire hazard, but if you store them entirely discharged, they might not charge again.
The reason for storing your battery outside your laptop is simple: Laptops get hot. If a battery is too hot, it starts to discharge itself and this, over time, reduces how long each charge lasts. Tests conducted by Cadex indicate laptop batteries under such conditions will last only 12 to 18 months, something I'm unhappily able to confirm.
So the battery is best kept somewhere else, preferably at room temperature. Some people recommend keeping it in the fridge (though not in the freezer), but I don't think you need to go that far -- just don't store it in your car in hot weather.
When it comes to using your laptop, there are ways to conserve the battery:
-- Your laptop shouldn't be working if you aren't. Windows computers have 'suspend' (or 'standby') and 'hibernate' modes. Suspend, says Howard Locker, director of new technologies at Lenovo, 'can extend the life of a fully charged battery to 50-plus hours.' Suspend turns the display and hard drive off, and all open files and programs are saved into memory. This allows a quick return to what you were doing, and is good for moving between offices or rooms. Hibernating freezes the computer, turns it off and then, when you switch it back on, returns to where you were; in this mode, a battery will last about six months before fully discharging, Mr. Locker says.
-- Switch off those parts of the computer you don't need. WiFi, Bluetooth, the DVD drive, the hard drive -- all use power and are best disabled when you don't need them. Some recent laptops make this easy (Lenovo's new ThinkPads, for example, have built-in software that allows you to do so), but you can also do it yourself if you dig around your laptop's Control Panel; the Windows XP operating system, for example, has power options that let you turn off the monitor and hard disk after they haven't been used for a while and you don't need them.
-- Reduce the screen brightness as much as you can. LCD screens are a power hog.
-- Don't squander resources on levity. Don't use your laptop's battery power for graphics, music or watching DVDs.
Of course, it also makes sense to carry a power adaptor with you when you're on the move. You'd be surprised where you can plug it in, especially if it's a travel model that can also be connected to cars' built-in cigarette lighters and the like. I was on a bus between Singapore and Kuala Lumpur the other day that had power outlets all over the place.
If your battery life still isn't enough and you don't mind carrying the extra weight, bite the bullet and buy a spare. The fact that buying a new laptop battery isn't easy or cheap -- and that most people don't buy a laptop thinking they're going to have replace the battery after a year or two -- is to me evidence that batteries are the laptop industry's dirty little secret that they don't want us to think about too much. (Just make sure you only buy them when you need them, and look carefully at the manufacturing date when you do. Don't buy old stock, and don't buy cheap brands.)
Follow all this advice and you won't necessarily be untethered, but you might at least be able to grab a coffee without crawling around on all fours.
Jeremy Wagstaff |
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