By Bill Moore
The advent of the practical EV would be a lot easier if a good battery were readily at hand. But as it stands right now, even the introduction of the much-anticipated 42-volt system in America may find itself struggling for the same reason.
Despite significant improvements in battery chemistry in the last decade, the automotive industry is still looking for that elusive super battery, a search that will only gain urgency as manufacturers begin engineering the first generation of 42 volt systems.
Menahem Anderman, who is the president of the Advanced Automotive Batteries, a research and consulting group, has been involved with the technology for almost 20 years. He's not only watched the progress of battery development but also participated in it.
Back then he, like many others, anticipated the emergence of advanced battery technology that could provide an electric vehicle with a 250-mile range. But despite millions of dollars in research, this super battery with 200kW/hr per kilogram capacity simply hasn't materialized, especially at a price of $3000 for a complete battery pack.
"It was such a high-in-the-sky goal that when you look at what battery technology was at the time, lead-acid and NiCad, we'd need three or four times the performance at a quarter of the price. . .
"I was involved in with some of the most exciting nickel cadmium development in collaboration with Mercedes Benz and Volkswagen in the late 80s and still it was limited by the fundamental technological limitation of batteries for electric vehicles, particularly NiCad."
The Hunt Is On
Menahem, who speaks with an Israeli accent, told EV World that in the last three years, he has seen a shift in the automotive industry, one that he finds very exciting and may bode well for both hybrid and battery electric vehicle development.
"Vehicle manufacturers have come up with all kinds of increased electrical functionality onboard the vehicle, but not going all the way for a full battery-powered electric vehicle, which is such a difficult goal to reach from a technology point of view."
Instead, Anderman explained, carmakers are creating vehicles with every more demanding electrical loads, from power accessories that simply outstrip the capabilities of the standard 14-volt alternator, 12-volt battery, through a wide spectrum of hybridization architectures.
"What's happened is all those different vehicle technologies are requiring different levels of battery performance, and of course, life. And the exciting them for many of us in the industry is that the two things are so tied (together). In order wordsŠ vehicle technology is very much tied to available battery technology."
He observed that carmakers will go in the direction that battery technology will let them, be it true battery-assist, mild-hybrid or just auto stop/start.
"The difference from the 80s to where we are now, fifteen years later, is that the batteries are 70, 80 percent there. We just need a little more performance and a little lower cost, and particularly more life."
"It's close and its so close that the vehicle people are getting more and more involved in what can batteries really do."
When Anderman says batteries are "almost" there, he is speaking generally. In his view, the biggest hurdle facing the technology at present is finding ways to extend the life of the battery itself. He pointed out that engineers are faced by a dilemma. They currently have to limit the hybridization system they design so as to not drain the battery and severely shorten its life.
This means, for example, that while a 42-volt architecture with auto stop/start may be feasible in Europe where most cars don't have air conditioners, the same system may not work well in the US. Nearly every car sold in this country today comes equipped with a powerful, power-robbing AC unit that would quickly drain a battery during stop and go traffic if the vehicle were equipped with auto stop/start.
Anderman explained to EV World that about 9 years ago, engineers began to realize that if they wanted to incorporate new convenience and performance features in their cars, they'd have to have more electrical power than the current 12-volt system could provide. This led to the development of the 42-volt system.
After the appearance of the Toyota Prius with its electric-assist, automotive engineers started to wonder if in addition to providing power for various accessories, they might also be able to incorporate some of the features found in the Prius. The hybrid's auto stop/start feature, which helps improve
fuel economy and lowers emissions, was particularly attractive. "The movement that initially came from interest in convenience features on the vehicle, and the movement that started from hybrid vehicle for fuel efficiency and . . . pollution reduction has merged into a continuum of various levels of hybridization. . .
Anderman stated that it is now becoming difficult to distinguish what constitutes a hybrid vehicle since the "continuum" now seems to run from 42-volt systems, to "soft" hybrids, mild-hybrids to power-assist hybrids. The electric demands of these new systems now run anywhere from 3-4kW up to 100kW, he said.
What Role for Lead-Acid?
While the common lead-acid battery has been the mainstay of the automotive industry through most of its first century, EV World asked what role, if any, it would play in the cars of the 21st century.
From his research, Anderman doesn't see the market for 12-volt SLI lead acid batteries beginning to decline until late in this decade. This is because he sees production volumes of the 42-volt system being small for sometime to come.
One thing is not clear at this moment, Anderman admitted, although his clients have asked him this on many occasions lately. Will the flooded, lead-acid battery have a place in the 42-volt system or will manufacturers need to switch to more advanced technologies, starting with advanced AGL-type lead-acid batteries?
Lead-acid batteries face two daunting obstacles that will limit their usefulness in increasingly hybridized designs. While they are low-cost, they are also are low in energy density and have to short a cycle life, typically a year or two at best if used as part of a hybrid-electric power assist system. This is simply not long enough to be practical from the manufacturers - - or consumer perspective. No one is going to want to change his or her battery every year.
The Future of NiCad
Because of his earlier work with NiCad batteries, they hold a special place for Anderman. He even thinks they are probably unexcelled at this point in terms of overall cycle life compared to other batteries.
But because of the heavy metals used in them, he also believes their days are numbered. He observed that it is almost impossible to build a new NiCad battery plant in Europe, where (ironically) most of the battery electric cars are powered by NiCads.
"The environmental pressures are mounting and it is very, very difficult for a battery company to build a new NiCad factory."
Anderman stated he was involved in the construction of the last NiCad battery plant in America and that when this company approached US carmakers, they were told that Detroit simply isn't interested in NiCads. He pointed out that nickel metal hydride batteries have progressed so far that even though they are somewhat more expense than NiCad, they have become the battery technology of choice for hybrid-electric vehicles. They also don't have the same environmental problems that NiCad has.
The Immediate Future Belongs To NiMH
"There have been very significant improvements in nickel metal hydrides in the late 80s relative to high temperature charging efficiency," Anderman stated, "which was one limitation of nickel metal hydride for automotive as well as computers."
He remarked that the reason NiMH batteries are no longer used in laptop computers is because of the heat generated by the newer Pentium processor.
"High temperature charge efficiency has been the number one technical barrier. There has been significant improvement with the use of additives in 1999-2000. It's really just starting to find itself into product in the last 12-18 months."
Anderman believes there is still room for improvement of the NiMH battery. One area is the batteries low-temperature performance. He said there is a lot of work going on, mainly in Japan, to solve what he considers is the second biggest shortcoming of NiMH.
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