by joelado, Sun May 13, 2007 at 07:09:31 AM EDT
In 1980 Stanford Ovshinsky patented a battery that was supposed to revolutionize the world. A battery that he knew could take almost unlimited charges and discharges, a battery that held far more energy at half the weight of lead acid batteries, a battery whose thermal properties were balanced with metals that combine endothermic and exothermic reactions to prevent thermal runaway, which is an explosive reaction common to the first iterations of lithium-ion batteries. Twenty seven years later those batteries are just beginning to have the impact they promised a quarter of a century ago.
NIMH batteries have grown in their use since the mid 1900s in small designations such as AAA, C and D sized typically designed for use in the home. In the early years of camcorders and laptops NIMH were the battery of choice. Ten years ago when the first modern hybrids were being designed and EVs were being readied for California's markets NIMH batteries were looked upon as the way to an electrified transportation future. At that point advancements in large format NIMH batteries seemed to have stopped at Ovonics. The electric vehicles (EVs) of the Zero Emissions Mandate that finally used the Ovshinsky batteries did well with ranges typically of 130 to 180 miles.
The small cell NIMHs kept seeing improvements over the years. Today NIMH small cells have improved in energy density by 80% and are 30% lighter than the batteries of ten years ago. The improvements made to NIMH chemistry was never incorporated into the Zero Emission Mandate EVs. Panasonic began talking about the incorporating its improvements to NIMH EV batteries just after the ZEV mandate was removed, however, Ovonics, now doing business as Cobasys with its GM owned shares now owned by Chevron oil company, prevented Panasonic from making the new and improved large format NIMH batteries.
A NIMH battery made today with these improvements would be a completely different battery than that of the ones installed in electric cars a few years ago. At EDTA I saw the casings for a new NIMH battery. They were 1/4 the size of the old green iron sided ones used in the EV1. They had inlets for liquid thermal management guarantying even longer life and the cases were made of light grey plastic which replaced the heavy steel of the original batteries. These cases were clearly marked on the top Cobasys NIMH. These were just the casing being displayed by the casing manufacturer, but it was a clear indication that the story of NIMH had changed.
Are NIMH batteries as energy dense as lithium-ion batteries? No, but they are a proven commodity. They are known to last, and last, proving themselves in Southern California Edison's fleet of RAV4 EVs. Many going over 100,000 miles and few reaching 150,000 miles on the original battery pack. Since the greatest cost of an EV is in the battery, NIMHs that last the life of the vehicle would be looked upon as just the price of the vehicle, not a separate expense. Lithium-ion batteries are still new in EVs. We don't know what can happen with that technology in the long run. I want them to last as long as the vehicles like NIMH but we won't know that until they have been around in vehicles for a while. Waiting and seeing if lithium-ion batteries will last, will keep GM from making a battery electric vehicle or the hybrid Volt, forever, since they can always claim that they don't know whether the battery will last. NIMHs, we know lasts. The risk to the buyer is lower then with the unproven Lithium-ion battery.
Let us look at what would life be like if the improved versions of NIMH were incorporated into the modern EV. If the RAV4 EV were redesigned to handle these lighter, more energy dense NIMH batteries, one could easily see that the range would be much, much higher. The higher the range is the greater the utility of the electric vehicle. Ranges in the 200 mile area would be likely for RAV4 EVs. You would be hard pressed to find someone who, on a regular basis would need a greater range than that. Coupled with the batteries long life and you can see that the battery the car makers are looking for is already here and it is the NIMH battery.
The price of small format NIMH has come down significantly over the past ten years. The price of an AA NIMH battery where I live has leveled off at to about $2.50 a battery at retail. At that price I have had a hard time purchasing the batteries because they always seem to be sold out. I use HIMH batteries for every battery application in my house. To save money, I purchased a bulk pack of 20 NIMH batteries for 19.98 mail order. They are rated at 2500 mah each. This is a lot better than the batteries I bought about 6 years ago that cost me retail about $10.00 a piece and could hold only 1500 mah. I strongly believe that if NIMH large format batteries were allowed to stay in the marketplace like the AA batteries have, similar increases in energy with a similar decrease in price would have occurred.
If I were to swap out the lead acid batteries that are in my electric vehicle today with NIMH D cell batteries it would cost me around $3,500. Not that far off from what I paid for my Trojans golf cart batteries, which was around $2,000. These D cell batteries would take up half the space and would be far less than half the weight and last the life of my vehicle never needing replacement. A large format NIMH battery would end the supremacy of the lead acid battery in traction applications such as in golf carts, NEVs, floor scrubbers and more. They would simply be a better replacement battery being lighter and lasting much, much longer.
I have had a question in my head for some time now. Why doesn't Ovonics/Cobasys/Chevron make a NIMH battery and go after the indoor electric utility vehicle battery market? You know what I am talking about. At night in large malls and airports there are hundreds of large format battery powered vehicle used for scrubbing floors, transport people, maneuver shopping carts around, electric rolling platforms and cherry pickers, and the list goes on. Here the advantages of NIMH would clearly render the old lead acid batteries obsolete. It is a market that exists, is large, with managers always looking to reduce their long term costs.
For EV owners, who have grown accustomed to replacing batteries every few years, being able to find NIMH regularly available in large formats would be a welcome change. There even would be a place for NIMH batteries in the starter battery market. People always seem to need to replace their dead lead acid batteries. Why not give the consumer the chance to pay double for a battery that they know will last much, much longer. It always makes me wonder why Ovonics doesn't go after the lead acid battery market. Why not go after a market they know to exist? I know I would buy an NIMH battery to start my gasoline powered car. Wouldn't some of you?
PS. This June 2nd and 3rd the Power of DC demonstration of EVs has been greatly expanded. In the years past we only held an electric vehicle drag race. This year we are holding the drag race again at the Mason Dixon drag way on June the 3rd, and we have added a whole new day to do an automobile autocross. A typical autocross is a series of timed events. It is like auto racing only instead of racing side by side you race against the times of the other competitors. The areas of focus for our event are AutoCross, ScooterCross, Range Rally (8.5 miles), and Show-n-Shine. Go see the link http://www.powerofdc.com.
Because of the greatly expanded event we need money. Not big money. These events are mostly operated by volunteers, but little money. Money for trophies, money for the use of the venues, money to rent equipment needed to maintain human intestinal comfort, banners, literature and more. A small check of $10 to $20 dollars would be very useful and greatly appreciated. Make your check out to EVA/DC putting in the memo line "Power of DC" and send it to:
4314 Ann Fitz Hugh Drive
Annandale, VA 22003.
The Electric Vehicle Association of Greater Washington, D.C. is a non profit (501 [c]3) organization so your contributions are tax deductible.