How to Build a Better Battery

Feb. 21, 2013

Let’s face it; battery technology is not keeping up with electronics.  It is time to find a way to make a battery that will keep pace with the needs of electrical and electronic equipment.  While the electronics industry continues, after over five decades, to follow Moore’s law, battery technology has reached a plateau.   In fact, it appears to have been on that plateau for a while.  Even the battery manufacturers haven’t figure out what the next step is.

It’s not like batteries are new technology as they have been around since Alessandro Volta built the first battery in 1791.  In fact, they may have been around for a couple thousand years.  An archaeologist discovered what may have been some of the first batteries in 1938.  Called the Baghdad batteries these devices are estimated to be over 2000 years old.  They consisted of terracotta jars containing an iron rod inside a rolled copper tube.  No doubt the jars were filled with some kind of electrolyte. No one knows what they did with these things, but, in any case it is an old technology.

The issue is getting the most electrical energy possible into the smallest and lightest package.  One measure is specific energy expressed in terms of Watthours/kilogram (Wh/kg) where a watthour is the battery voltage multiplied by the ampere-hour rating.  Energy density is measured in terms of Watthours per volume (usually a liter) or Wh/L.  Lithium batteries have the highest ratings in both cases.  No wonder they are so popular for portable devices like tablets and smartphones and electric cars.

Yet lithium batteries have their problems.  The Boeing Dreamliner 787’s lithium ion batteries caught on fire and have now grounded this magnificent plane.  The real cause has yet to be identified but it probably has to do with cramming too many highly volatile chemicals into a space too small thereby creating thermal problems.  It is not unlike the problems with the lithium ion batteries used in laptops and cell phones back in 2006 and 2007.  That problem has been fixed, but Boeing is now offering a tentative fix to get the 787s back in the air until the real problem has been identified and corrected.

Lithium ion batteries are also the favorite of electric car manufacturers.  They offer the most power per weight and size than any other type of battery.  But they are very expensive and could have the same kind of fire problem.  That’s why the Prius still uses nickel-metal-hydride (NMH) batteries.  They are bigger and heavier but safer.

Batteries are still the weakest link in making an all electric vehicle that is as practical and affordable as our current gasoline cars.  Besides high cost, the downside to all-electric vehicles is their short range.  The top range is about 75 to 100 miles for an affordable car like the Nissan LEAF.  Cars like the Tesla can go farther but have bigger and more expensive batteries putting them into the super expensive  luxury class.  Who wants a vehicle that will run out of juice during even shortest commutes or shopping trips?  And few charging stations are available.  Even if a charging station is available, it can take an hour or more to charge up.  It only takes 5 minutes or so to fill up you tank with gasoline from the thousands of gas stations around.  No wonder the electric cars, first invented in the mid-1800’s totally failed by the early 1900’s.  That is still a problem today.

The last big battery breakthrough was the lithium battery developed by Sony back in 1991.  Since then there has just been the usual tinkering, fine-tuning and incremental refinements.  All the possible chemicals suitable for batteries have already been identified and explored.   Nothing new is on the horizon.  The biggest developments have been in packaging and manufacturing and especially in making batteries safer.  Now what we really need is a CR2032 coin cell with the watthour capacity of a Sears Diehard, all for less than a dollar. 

For a while, many thought the fuel cell was the answer.  It is not, especially for smaller portable items.  The fuel cell requires sources of oxygen and hydrogen to function.  The oxygen can be extracted from surrounding air but you still need a hydrogen tank or some chemical unit that can extract hydrogen from methane gas or hydrazine or some other chemical.  That is really inconvenient.  On top of that hydrogen is also a dangerous chemical, perhaps even more so than lithium.  And where are those hydrogen gas stations?  Scratch fuel cells as the answer.

It will be interesting to see what is next in batteries. Maybe the big breakthrough will come in solar panels.  In the meantime, don’t leave your smartphone/tablet/laptop charger in the hotel room and don’t forget your jumper cables.

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