Lithium-Ion Batteries

Lithium-ion Batteries:  Key Chevy Volt Technology

by Steve Auger

Chevy Volt

The much anticipated Chevy Volt, which is expected to start production in the 2011 model year, has the media abuzz.  Claims of 230MPG fuel efficiency and recent news announcements regarding the selection of  South Korean lithium-ion battery manufacturer LG Chem and acquisition of battery manufacturing facilities have news rooms hopping.  But what is all the commotion about?  230MPG is in reality, a meaningless number when an automobile is powered mostly by electricity.  Yes the first 40 miles will be powered by a lithium-ion battery pack.  And lithium-ion has had a difficult tenure in smaller devices such as cell phones.  Two well-known lithium-ion issues are:  (1) catching fire;  and (2) short life time (2 years). 

Lithium-Ion Performance

So what is all the noise about?   Why does GM think the Lithium-ion battery will perform better in automobiles than in consumer electronics?  General Motors and it's major stakeholder, the U.S. government - or should I say the U.S. taxpayer, are betting the farm on the Chevy Volt and other branded vehicles that work on lithium-ion battery pack technology.  In this author's opinion, the lithium-ion battery pack may be as significant for the future of the United States as the mass production of the internal combustion engine.  If the technology works that is.

Battery Pack Design

It is apparent that significant amount of effort has gone into not only selecting a particular lithium-ion battery manufacturer, but also the engineering of a sophisitcated battery pack that not only packages a large number of individual batteries but also provides micro-based thermal / voltage / current monitoring.  The monitoring is necessary in order to predict the amount of charge present in each cell - such information is needed to prevent over-charge and too much depletion.  GM engineers have designed in enough spare capacity so that the battery pack only needs to be charged to 80 percent of it's theoretical capacity and never discharged to less than 30 percent.  The theory is that adherance to these restrictions will extend the battery to 10 years or 150,000 miles without noticeable deterioration.

The Future is Lithium-Ion

GM appears to have hit the nail on the head.  The average car owner drives to work within range of the battery.  It is predicted that 75% of Chevy Volt car trips won't use a drop of oil!   And Chevy owners will never be stranded on the road unlike Nissan Leaf owners will with no gasoline backup.  City smog will be a thing of the past and we may reduce our dependence on foreign oil.  This of course depends upon how our new requirements for electricity are satisfied.  BUT, by switching to this new technology, the United States will become dependent on foreign supplies of lithium.  So instead of being dependent upon the Middle East for oil, we may find ourselves depending on Bolivia as a source for lithuim.

One thing that has been clear regarding GM's initiative:  Toyota is reluctant to design lithium-ion batteries into cars.  Being the leader in green cars with the Prius, Toyota isn't willing to gamble on this emerging technology.  My prediction is that the Prius and other such hybrids will be left in the dust over the coming decade.  The introduction of the Chevy Volt will be in the history books for generations to come.