Tag: li-ion

Scientists make battery breakthrough

lithium-ion batteryA group of researchers at Stanford University claim to have invented an aluminium battery that will spell the end of lithium-ion batteries.

The batteries are made of a mix of graphite and aluminium and the Stanford scientists said that commercial production of the new style batteries could charge a smartphone in less than a minite.

Lithium-ion batteries have the tendency to catch fire, but the Stanford scientists claim the prototype they’ve built won’t do this.

And the aluminium prototype has shown in tests that it will charge much longer than comparable lithium-ion batteries.

The findings of the science are produced in the current edition of Nature. An aluminium ion battery has a negatively charged anode made of the metal.

Aluminium is also much cheaper than lithium so costs will be lower. The team said it still needs to make improvements for the battery to compete with the current technology.

German boffins come up with ultra long-life batteries

A team of researchers from the Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg, which roughly translates as the centre for solar and hydrogen development, has come up with a new Li-Ion battery technology that could bring affordable electric cars a step closer.

The new batteries retain most of their capacity even after 10,000 recharge cycles, which means they should be good for 25 years, or more.

One of the biggest teething problems facing electric cars is the relatively short lifespan of their battery packs. Many experts claim the batteries have to be replaced every five to seven years, and they are pretty pricey, too.

The team claims their new power pack retains more than 85 percent of the initial capacity even after 10,000 cycles. That means they will probably never have to be replaced – the rest of the car will fail before they do.

As with most battery breakthroughs, there’s a catch. The technology is still not ready for mass adoption and it needs tweaking. It is unclear when, if ever, it will be employed commercially, reports Hothardware

Boeing groeing tough battery tests for Dreamliners

Boeing is desperately trying to get its 787 Dreamliner fleet back into the air and it is now testing the plane’s volatile Li-Ion battery system to a rigorous standard that it helped develop itself.

The strict new standard was never employed on the Dreamliner and in retrospect it might have been a good idea to run the tests before it was pressed into service.

The Dreamliner was the first commercial jet to use lithium ion batteries, which are a great way to save a bit of weight, but in some cases they can be more dangerous than exploding footwear and underwear. Following a couple of highly publicised battery incidents, the Dremliner fleet was grounded in January. Since the battery tech was all new, the FAA had to approve a set of special conditions for fire safety on the Dreamliner in 2007.

A Boeing committee issued a set of guidelines in March 2008 to minimise the risk of Li-Ion batteries. However, Boeing never had to meet the more stringent guidelines. The FAA never required it and Boeing chose to ignore them.

Boeing is now scrambling to get the Dreamiliner battery system up to spec and apply the tougher RTCA standard, published in 2008. However, it seems like it is too little too late.

Former NTSB board member John Goglia told Reuters that Boeing’s decision to use the  tandard is basically an admission that the company didn’t do a good job to begin with. Last month, the NTSB questioned the assumptions made by Boeing and the FAA during the battery certification process in 2007.

A Boeing spokesperson said the RTCA standard was not used because the it came too late, after Boeing had completed certification. Boeing is about one-third through testing under the stricter RTCA standard and it is likely to get the job done in a couple of weeks.

It is still unclear when the Dreamliner fleet will start flying again. 

'Nanoscoop' Li-ion battery charges over 40 times faster

Scientists have developed a completely new nanomaterial that can offer recharge times for automotive batteries over 40 times faster than previously achievable, as well as opening up possibilities for th swift charging of mobile and laptop batteries.

The new generation of high power lithium (Li)-ion batteries, discovered by Professor Nikhil Koratkar at Rensselaer Polytechnic Institute, are expected to provide extremely high charge and discharge rates that causes the current incarnation of the Li-ion batteries to deteriorate quickly before failing to work at all.

The technology used is the new nanomaterial, dubbed ‘nanoscoop’ due to its resemblance to a scoop of ice cream, featuring a unique material composition, structure and size.

The research team at Rensselaer has successfully demonstrated how a nanoscoop electrode can be charged and discharged between 40 and 60 times faster than that of a conventional battery, managing to maintain this performance over 100 continuous charge cycles, opening the door for new high power, high capacity Li-ion rechargeable batteries.

“Charging my laptop or cell phone in a few minutes, rather than an hour, sounds pretty good to me,” said Koratkar. “By using our nanoscoops as the anode architecture for Li-ion rechargeable batteries, this is a very real prospect. Moreover, this technology could potentially be ramped up to suit the demanding needs of batteries for electric automobiles.”

Electric cars currently use supercapacitors to perform power-intensive functions, including starting the vehicle and rapid acceleration, in conjunction with conventional batteries that deliver high energy density for normal cruise driving and other operations. The researchers believe that nanoscoops may now enable these two separate systems to be combined into a single, more efficient battery unit.

According to the team at Rensselaer, the reason that contemporary batteries take so long to charge is that they are purposefully programmed to do so.  This is because the anode structure of a Li-ion battery physically grows, with discharging having the opposite effect, causing an amount of stress that will cause the battery to fail if done too quickly.  

Nanoscoop technology effectively relieves the need to protect against battery failure by intentional slowing down the charging.

The nanomaterial is constructed to withstand such a build up of stress, made with a carbon nanorod base topped with a thin layer of nanoscale aluminum (Al) and a ‘scoop’ of nanoscale silicon (Si).  Being engineered in this manner means that the nanomaterial is able to accept and discharge Li-ions at extremely fast rates  without sustaining damage.

It is the segmented structure of the nanoscoop that allows the strain to be gradually transferred from the C base to the Al layer, and finally to the Si scoop. This natural strain gradation provides for a less abrupt transition in stress across the material interfaces, leading to improved structural integrity of the electrode. 

The minute scale of the structure also lends strength to the material. “Due to their nanoscale size, our nanoscoops can soak and release Li at high rates far more effectively than the macroscale anodes used in today’s Li-ion batteries,” said Koratkar. “This means our nanoscoop may be the solution to a critical problem facing auto companies and other battery manufacturers – how can you increase the power density of a battery while still keeping the energy density high?”