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Top industry figures says there's no sure fire method of predicting internal shorts

For the last two decades demand for lithium ion batteries in mobile devices has exploded, but so did safety concerns.  Apple, Inc. (AAPL), Sony Corp. (TYO:6758) and several others struggled with exploding or smoldering products.

I. Expert Panel -- How to Make Batteries Safer

Now it's the transportation industry that is grappling with these issues.  This week a panel of experts met at a forum sponsored by the U.S. National Transportation Safety Board in a bid to answer the question of how to prevent the wave of battery fires that have swept the electric vehicle and commercial aircraft industries.

The answers were not terribly reassuring.  While experts said the issue of short-circuits was known and best-practice preventive measures were included in most large battery systems, that there's no sure-fire method of protecting a battery from its own internal flaws.  


And the mechanism by which short circuits start fires is still poorly understood.  Laurie Florence, principal engineer at international battery safety certifier UL, says that you can shoot a nail into most lithium ion batteries, triggering a short circuit, but no fire.  However, more subtle internal design issues can trigger short circuits that do lead to fires.

Daniel Doughty, president of Battery Safety Consulting, urged the industry at the forum to embrace research into design isolated cell technology that prevents a fire in one cell from spreading to the next.  He also urged industry leaders to develop better technology to diagnose and predict internal short circuits.

Battery manufacturers already rely on a cruder fault prevention technology -- additives.  The liquid lithium ion fluid -- roughly 25 percent of the contents of a typical cell -- is highly flammable.  Typically additives are mixed into this volatile liquid to reduce the fire risk.  But these additives also frequently reduce the power capacity/delivery of the battery, hence raising costs and cutting battery life.

Janet McLaughlin, deputy director of the U.S. Federal Aviation Administration's hazardous materials safety programs, comments, "We all know lithium batteries are hazardous materials."

On the other hand, replacing batteries also isn't cheap.

II. Battery Fires Hit Boeing, GM, Hard

Both Airbus, a subsidiary of The European Aeronautic Defence and Space Company N.V. (EADS) (EPA:EAD), and The Boeing Company (BA), the world's top two commercial aircraft companies, initially tapped lithium ion batteries for auxiliary power systems in their new flagship aircraft, an industry first.  Airbus recently dropped plans for lithium ion batteries in its upcoming A350 after backpedalling amid fire concerns.

Those concerns allude to rival Boeing's efforts, which are still forging ahead despite major setbacks.

In January the battery module in the Dreamliner 787 caught fire in Boston, Mass. while on the ground.  Just a couple weeks later, a Dreamliner in Japan was struck by a serious battery fire.  After the second incident Boeing agreed to ground the Dreamliner and search for a solution.
 

Boeing 787 production line [Image Source: Boeing]

Since then, Boeing has redesigned the battery module.  And while an investigation into the previous fires is still ongoing, the FAA has agreed to permit Boeing to start testing the new module.

The auto industry has also been struggling with battery issues of its own.  Fisker suffered a pair of fires last year, although the company insists they weren't battery related.  But General Motors Comp. (GM) did trace fires in its Chevy Volt electric vehicle back to malfunctions, triggering a quasi-recall.  In the aftermath of the recall GM executives were forced to testify before Congress.  GM recently acknowledged that the publicity from the fires hurt Volt sales.


Chevrolet Volt [Source: TECHVEHI]

But again, in automotive applications automakers are struggling with the delicate game of risk regarding batteries and additives.  Fewer additives might give customers more miles on a charge -- but they might also cause a fire.

III. Soft Demand Tempts Some to Cut Corners

A final issue is soft demand.  The struggles of electric vehicles -- caused in part by poor battery range and public awareness of battery safety issues -- have cause the industry to badly miss sales growth predictions.

In 2002 only 800m lithium ion cells shipped.  This year roughly 5.5 times that total -- 4.4b cells -- shipped.  Glen Bowling, vice president of sales at Saft Specialty Battery Group, a producer of lithium ion batteries, comments to Reuters, "The growth in the mission of lithium-ion batteries is substantial. It's a stretching of the technology boundaries and we have to be professional when we do that."

But the industry is also hurting.  Massachusetts Institute of Technology materials engineering professor Yet-Ming Chiang comments, "[2008-era predictions of 2011 demand] were off by more than a factor of 10.  This created a great deal of stress among those who manufacture batteries.

Battery product
LiIon battery-makers have been under increasing financial stress amid missed sales targets.
[Image Source: ANL]

Those miscalculations have caused manufacturers and startups to load up on expensive lithium metal and overproduce.  Professor Chiang says there's enough idle lithium cell stock to power 400,000 LEAF EVs from Nissan Motor Comp., Ltd. (TYO:7201).

Many companies have gone out of business.

Amid that market it may be tempting to the survivors to cut corners.  Survivors are desperate that Congress will back a fresh round of $7,500 to $10,000 USD electric vehicle tax credits proposed by President Obama to stimulate asales.

Sources: NTSB, Reuters



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RE: toyota avoided the tech & now we see why
By foxalopex on 4/16/2013 9:33:55 AM , Rating: 2
No Toyota did not use NiMH batteries because they were less likely to short-circuit. They used them because:

1. A Prius hybrid doesn't use batteries as primary driver, just mostly for acceleration. NiMH batteries are very good at generating burst power. You can easily damage Lithiums trying to do the same but in an EV the Lithium battery is so huge that it helps prevent this issue.

2. A short-circuit and resulting fire can affect any battery. Short circuit a lead acid battery in a regular car sometime and see what happens then if you don't believe me. The only EV to have caught on fire in the real world so far was the Fishker and that was due to a cooling fan getting jammed I believe which caused some non-battery part to overheat and catch on fire. (Embarrassingly bad design if you ask me.)

3. NiMH are cheaper than Lithiums but they don't store as much power as a NiMH. This is why you don't see a NiMH in cellphones. You can't build a small and thin cellphone and expect the battery to last if you use NiMH.

4. Power density is a major issue for EVs. I own a Chevy volt and the 500 lb lithium battery pack is equivalent to about a gallon of gas. (If you run the Volt on gas, it gets roughly the same distance.) Considering that the gas engine is very inefficient, this means the battery pack has in reality even less energy than a gallon of gas. A gallon of gas doesn't weight 500lb last I checked. This means for EVs the push is for more power in less space so that's why almost all EVs use Lithium batteries. A hybrid doesn't because it is gas powered. A car meant to be electrically powered almost universally uses Lithium for this reason. (ie Prius Plug-In)


By jackpro on 4/17/2013 10:29:04 PM , Rating: 2
learnt something thanks


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