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The ultimate battery. Lithium-air? Zinc-air? Hot air?


via Flickr © AndyArmstrong (CC BY-SA 2.0)

  • Search for the better battery technology has lasted 250 years
  • But the 'ultimate' battery remains elusive as the Loch Ness Monster
  • Improvements to lithium-ion batteries have reached a plateau
  • Interchangeable hydrogen fuel cells could be one answer

Back in the 19th century, the Victorians, brilliant innovators that they were, tried to store electrical energy by capturing lightning in jars. They eventually found out that it wasn't possible, well, not then anyway and not yet now either come to that, but for 250 years and more now the search has been on for methodologies and technologies that will enable the storage and controlled discharge of electrical power. Until now the main solutions, or partial solutions, have been batteries and capacitors.

We have Benjamin Franklin, US Founding Father and he of the kite, the key and the electrical storm, to thank for much of the early work in the field (literally and metaphorically). He experimented with an early form of capacitor and, in 1748, coined the word "battery" to describe a group of linked Leyden Jars.

Originally the term "battery" referred specifically to a device composed of multiple cells but the word has evolved to include single cell devices. Basically, an electric battery, consisting of one or more electrochemical cells converts chemical energy into electrical energy. Primary cells or "batteries" produce current as soon as they are assembled but drain it quickly while secondary cells/batteries are rechargeable.

Meanwhile, capacitors can retain a charge for a long time after power is removed from a circuit. Because of that capability the retained charge can be dangerous and cause a severe or even lethal shock when it is discharged as many a TV engineer can testify. Even something as common as a disposable-camera flash unit, powered by a humble 1.5 volt AA battery, has a capacitor which retain 15 joules of energy and can be charged to over 300 volts. It can deliver a nasty shock even when the throw-away camera has not been used for some time.

Today much of the research into improved or even revolutionary battery technology is the direct result of the global proliferation of smartphones. Thanks to the continuing sustainability of Moore's Law the number of transistors that can be fitted onto a silicon chip doubles every year or so and so does processing power. Unfortunately, progress in the search for a better battery is proving to be much more difficult. However, the age of the smartphone has exposed major shortcomings where battery technology is concerned. The reality is that the lithium-ion batteries used to power mobile handsets and laptops hasn’t changed in any significant way since Sony began to use them back in 1991 - and 25 years is prehistory where smartphones are concerned.

Think back to the early 2000s when a mobile phone would go days without the battery having to be recharged. Actually, you can still get a few handsets with a battery life of a week or so but they are very basic models and people want all-singing, all-dancing, bells whistles handsets with all sorts of apps, services and go-faster stripes that munch through batteries in a matter of a few hours. Consider this; the latest iteration of the iPhone is 16 times more powerful than the original device of nine years ago but its battery still lasts for less than a day.

Hit me with your Brinkley stick. Hit me, hit me

There have been incremental but largely marginal improvements in extending the life of batteries but that has been down to the use of more efficient processors rather than any battery technology breakthrough. That's because the lithium-ion batteries used in mobile devices are relatively simple and have reached the ultimate plateau in their development. The manufacturer's response to this stasis have as been to improve battery life by less than three per cent year-on-year by the remarkable expedient of actually making the batteries bigger! That's no long-term solution, hence the emphasis on developing something to replace lithium-ion technology.

Last year, researchers at the UK's prestigious University of Cambridge announced that they are working on a “lithium-air” battery. They say it may be the "ultimate battery" with 10 times the capacity of lithium-ion technology. Lithium-air battery technology is not new, it has been around since the early 1970s, but its major drawback was that the batteries could not be recharged more than a few times before they stopped working. The University of Cambridge team say they have solved the problem by using lithium hydroxide rather than the usual lithium peroxide.

Meanwhile, in the US, researchers at the Argonne National Laboratory in Illinois have demonstrated a lithium-superoxide battery that is superior to lithium-air technology. Elsewhere the US Department of Energy stumping up the cash to support 75 different 75 electricity storage projects being undertaken at Harvard, MIT, Stanford, as well as the Lawrence Livermore and Oak Ridge laboratories.

Another avenue of research is examining better ways of powering batteries. Intelligent Energy, a UK company, is looking at the use of hydrogen fuel cells, Company CEO Henri Winand, claims prototypes can power a smartphone for a week and points out that fuel cells can be swapped in and out of phones and other mobile devices as and when needed."

In case you are wondering, a 'Brinkley stick' is a safety device used to discharge high voltage capacitors and high voltage circuits. It's a simple thing, just a metal on the end of an insulated stick. the hook is connected to earth by an insulated wire. It is named after Charles Brinkley, an ferry boatman who was short of his his right hand but equipped with a fearsome steel hook to replace it. He ferried top secret radar development staff across the River Deben in Suffolk to RAF Bawdsey England. It does have another name but it is rather too rude to print here. Not too many people know that. As the late, great Ian Dury nearly wrote, "Hit me with your Brinkley stick, hit me, hit me, hit me, Das ist gut, c'est fantastique. hit me, hit me, hit me. A great song. It's actually called "Hit me with your rhythm stick" Have a listen. It will make you smile.

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