March 25, 2012 – Vol.17 No.2
RETHINKING ELECTRIC CARS -- PART 4.
by Bruce Mulliken, Green Energy News
Electric cars are selling better than hybrids when they were first introduced. Still, they're not selling anywhere near as well as the companies that produce them predicted. Company executives can't withdraw statements made a few years ago, but probably wish they could. They'd be more conservative in their sales estimates if they could say it all over again.
The focus of this series is to examine the two major factors that are holding back electric vehicle sales: Vehicle cost and range per battery charge. Those factors have a common connection, those expensive batteries. It's the high cost of state-of-the-art-ever-so-popular lithium-ion batteries that keeps car prices astronomical. Sure, car builders can put more battery capacity in cars for greater range (and solve that problem), but with every cell added the price goes up. With every cell added, too, additional weight gain must be taken into consideration. However, overall vehicle weight might be easier to shed than cutting the cost of those batteries.
Electric car builders, which now include most major car companies, are hoping that lithium-ion batteries will drop in cost during the next few years. In these hopes they're relying on the assumption that seems to be true for nearly all electronics: Cost always falls over time. Yes, the cost of computers, flat screen TV's, cell phones and you name it, have plummeted dramatically. But why? One reason is the steady refinement in factory production methods. Assembly lines are tweaked for efficiency, output, cost cutting and profits. Another way (and obviously the most common) is make the products in countries with low labor and other operating costs. Economies of scale play a role as well. Big plants with big output can make cheaper goods. The last is a combination of the other three: Sophisticated production techniques in big plants using cheap labor.
However, there's the rub that auto executives should be concerned about. Many lithium-ion batteries are already made in nations, such as China, with historically low labor costs. So they're relying on efficient production technologies and economies of scale to cut battery costs.
To compound the cost problem, lithium-ion batteries aren't exactly traditional electronics so really shouldn't be compared. Electronics use small amounts of exotic, expensive materials mixed with some cheap ones. Lithium-ion batteries use significantly more expensive materials, like lithium itself. Lithium isn't exactly in abundance on the planet such as iron or silicon, for example. Nor is it easy to obtain. It's not in everyone's back yard. To make matters worse, and jack up production costs, lithium is very difficult stuff to work with. Pure lithium reacts vigorously with water and thus humidity, so battery cells must be manufactured in dry-air conditions and cells must be absolutely air tight. Any flaw and the cells are useless. In production you can't touch pure lithium with bare hands. Moisture on finger tips will ruin it.
Who knows though? Maybe the auto companies are right. Maybe they have some inside knowledge, or some secret projects, to cut battery production costs. Maybe the cost of lithium-ion batteries will fall to levels that will make electric cars much, much less expensive. However, if they're just making assumptions based on electronics manufacture, they're making a heck of a big gamble. If so, they probably shouldn't put all their money on one bet. If lithium-ion batteries don't fall in cost in a big way, the game will be lost: Electric vehicles won't make it the marketplace.
Electric vehicle developers need an alternative battery chemistry as a back-up. My choice, as it has been for over a decade and a half, is zinc-air.
Simply put, the electrochemistry is this: In each battery cell oxygen from air slowly oxidizes pure zinc. As the zinc oxidizes electrons are available for use, like powering a motor.
Zinc-air has much going for it.
Zinc is dirt cheap. There's plenty of it on the planet. It's easy to get and easy to work with. You probably DO have some in your back yard. (Like the coating on an old roofing nail.) Zinc is easily recyclable. It can be deoxidized and used over and over again. Zinc-air devices have an incredibly long run times which translates into long range per charge or "refueling."
Variations of zinc-air electrochemical technologies have been used in the past in a number of developmental vehicles. Here are just two examples – there are others – from this publication:
--- From October 2000...
RECORD BOOK FOR FUEL CELL VEHICLE.
The EVictory from EVonyx has set a Guinness World Record - 217 miles - for the longest run on a single fueling in a modified production vehicle powered by a fuel cell. And the fuel cell was powered by zinc, not hydrogen.
The modified Honda Insight was supposed to run from outside New York City to Detroit without refueling, but only made it Howard, Pennsylvania. A technical glitch brought the car to a halt, not a lack of fuel. Engineers from EVonyx determined that there was enough energy remaining to complete the trip. The zinc-air powered Insight, (one of two developed) was chosen for its sleek aerodynamics and light-weight body shell. Voiding the warranty,the stock hybrid drive train was pulled out and tossed aside. If commercialized the cost of zinc fuel for the journey would be about $4.
EVonyx calls its metal-air fuel cell the RPC (tm) for Revolutionary Power Cell. The RPC, when in production, would be both refuelable and be rechargeable from an electric power connection. Spent oxidized zinc fuel would be recycled for reuse. The fuel cell is also designed to run on a variety of other metals.
According to the company, metal-air fuel cells have been under research and development for 30 years, but only recent technology improvements have increased power density dramatically. The EVonyx fuel cell operates at room temperature and is environmentally benign.
The company shows up on the web as Reveo and has significant patents related to zinc and other metal-air devices.
--- From June 2002...
POWERED WITH METAL.
There is the possibility that hydrogen fuel cells won’t be powering the cars of the future. Car manufacturers may decide that the hurdles of cost, reliability, fueling infrastructure and fuel handling are insurmountable. After all, just a few years ago all the focus was on battery electric vehicles. The promise of hydrogen fuel cells and hybrids drew car companies’ attention away from rechargeable cars (though many are still out there).
If not hydrogen, what’s next?
With almost no interest from car makers metal-air fuel cell developers have been toddling along building proof-of-concept vehicles. EVonyx built its record-breaking converted-to-zinc-air Honda Insight and Electric Fuel has built and tested its zinc-air bus. Now Metallic Power has successfully demonstrated a road-worthy zinc-air vehicle.
Metallic Power used four of its own prototype telecom backup-power zinc-air fuel systems to power a Geo Force converted to electric drive. Output from the zinc power system provided 12.2 kilowatts, approximately 16 horsepower. That, along with a small lead acid battery pack for additional hill climbing power, gave the car a top speed of about 48 miles per hour - not exactly a racing car.
A 12-liter supply of zinc pellets in electrolyte ran the car for 2.4 hours for more than 100 miles of driving under varied conditions and terrain. Cost-per-gallon of zinc-electrolyte fuel was about $2, and, of course, with this technology the zinc can be regenerated, or deoxidized as it were, and used over-and-over again. The car was refueled using hoses and funnels, though the company has a more sophisticated refueling/zinc-recycling technology under development.
So what’s so remarkable about the car? While hydrogen fuel cell development for vehicles has had billions in funding over a decade or so, Metallic Power has had only $27 million in funding to date - and that money has been used to develop ALL of the company’s projects. The car was almost an afterthought, needed to meet grant obligations. So, the car may seem somewhat crude, but for the amount of funding available, a spectacular achievement. Imagine what this technology could do with billions to spend.
Metallic Power is long gone.
Zinc-air is not without its problems. Zinc-air devices would likely be heavier than lithium-ion batteries. Further, cell voltage is less, so more cells are needed to build up voltage and provide high power to electric drive motors.
Some companies are working on electrochemically rechargeable zinc-air devices which could feasibly work well with the electric vehicle charging infrastructure now being built. Rechargeable zinc-air cars could be recharged at home as well.
Other devices are “primary” (meaning use once) such as disposable zinc-air hearing aid batteries. Still others are mechanically or chemically rechargeable batteries. Call them zinc-air fuel cells since they can be refueled with fresh zinc. (I once rode on a city bus developed by Electric Fuel which was powered by zinc-air batteries (or fuel cells) that were mechanically rechargeable. At the end of a day's run the batteries were removed, rebuilt with fresh zinc and reinstalled in the bus. The company, now part of Arotech, had an entire system developed for battery swapping and recycling.)
One company today working on primary, but mechanically/chemically rechargeable zinc-air batteries is QuantumSphere, of Santa Ana, California. You'll have to watch the YouTube video to understand what they've developed: a zinc-air refuelable battery for recharging other batteries. (Engineers watching the video... keep a pencil and paper in hand. Jot down some of the specs as spoken by the narrator.)
One comment stands out in the video. The device QuantumSphere developed was designed and built in a week. One week! (Well, one long week with four people putting in 250 hours combined.)
Mechanically rechargeable zinc-air batteries combined with automated battery swapping, similar to that being developed by Better Place, could be the lowest cost way to go for electric cars. The downside here is that the charging infrastructure now being built would be obsolete before it really gets started.
One thing not to worry about though is survival of the now large lithium battery industry. The market for lithium batteries for consumer electronics is now far bigger than for electric cars. Those companies will survive with or without lithium-ion powered cars.
If zinc-air was adopted for use in electric cars and trucks there’s already a natural line of technological advancement. The next step beyond zinc-air is aluminum-air and magnesium-air, both of which would offer even greater power output than zinc. Someday we could be fueling our cars with recycled soda cans.
RETHINKING ELECTRIC CARS - PART 1
If EV’s don’t catch on at a quicker pace, manufacturers might have to go back to the drawing board.
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