(May 2003) To compete in the marketplace, Lead-acid must look at the benchmarks Nickel-metal hydride has set to date, being that this battery system is the popular commercial choice for current hybrids on the market. Because of its interest in plug-in hybrids, the Electric Power Research Institute (EPRI) has conducted several studies on hybrids, both non-plug-in (HEV-0) and plug-in (HEV-20 and HEV-60) and has compared results with conventional IC engine models. (Note that the HEV-0s in EPRI’s studies are “full” hybrids using a parallel design that deliver about 50% fuel economy improvement, but does not use off-board electricity.) Since the ELABC (European Lead Acid Battery Consortium) is looking to successfully replace a Nickel-metal hydride battery system with a VRLA (valve regulated Lead-acid) system in a Honda Insight, the information in this article will only consider the HEV-O.
On March 23, 2003, EPRI in their most recent study, “Advanced Batteries for Electric-Drive Vehicles,” gave Nickel-metal hydride batteries a glowing report. This study assesses the state of this battery technology and presents one of the first life cycle cost analyses for vehicles with Nickel-metal hydride batteries. Perhaps a portion of their impetus to work with Nickel-hydride batteries is based on the success of the RAV-4 which traveled over 100,000 miles on the original batteries with “no appreciable degradation in battery performance of vehicle range.” Projections for battery life suggest that a possible 130,000 to 150,000 miles can be obtained.
In 2000, the battery technical advisory panel of experts reported on a new positive electrode additive to improve high temperature charge acceptance. Most recently, Saft has also presented documentation on bench testing showing that Nickel-metal hydride batteries have demonstrated 2,841 to 2,922 cycles between 80% and 20% SOC (state of charge). This appears to be substantiated by tests at Ford Motor Company where data shows that considerably more than 2000 cycles between 100% and 20% SOC resulted in an improved cycle life. EPRI has concluded that “greater battery cycle life means it is highly probable that Nickel-metal hydride batteries can meet 130,000 to 150,000 lifetime mileage for an HEV-0.”
However, for the success of the HEV-0, and ultimately plug-in hybrids, many variables must provide a positive direction. The cost of advanced batteries “is highly dependent on the establishment of a growth market situation, a predictable regulatory environment and consistent production volumes that encourage capital investment in production capacity and line automation by battery and automotive manufacturers,” said Bob Graham, EPRI’s area manager for transportation. (BD note: Perhaps the next study will need to focus on if/when and how these variables will be accomplished.)
For complete reports on the HEV-0 and the HEV-20 and HEV-60 Plug-ins, including the most recent study, “Advanced Batteries for Electric-Drive Vehicles,” request copies from the EPRI Distribution Center, 1355 Willow Way, Suite 2478, Concord, CA 94520, Pleasant Hill, CA 94523 (800) 313-3774.
Other thoughts on HEVs
In an article entitled “Are Hybrid Vehicles Worth it?” in the IEEE Spectrum, March 2001, Lester B. Lave of Carnegie Mellon University and Heather L Maclean of the University of Toronto answer the question , “No.” In the text, the authors compare the Prius to the Corolla and conclude that “HEVs cost too much at present to make economic sense.” Research at Edmunds.com seems to confirm this statement. In comparing the Carolla with the Prius, their research estimated that it would cost over $29,000 over a five year ownership period for a Prius, whereas a Corolla would only cost $26,000. Factors included in this five year period were maintenance, insurance, repairs and financing. Hybrids also have more depreciation. According to Jeannine Fallon of Edmonds.com., with the hybrid technology advancing quickly, what seems really advanced now could be outdated in five years, reducing the vehicle’s resale value.
Lester Lave and Heather Maclean see buyers attracted to HEVs, not for their fuel economy and lower emissions, but rather by the large electricity supply on board to power more applications in the vehicle. (Ed note: This large electricity supply has really nothing to do with hybrid configuration.) Unfortunately, the good fuel economy incentive has not been a positive factor as shown by sales of the Honda Insight (a two seater which has the highest gas mileage, 51 m.p.g., as noted by Consumer Reports). In March 2003, only 22 vehicles were sold nationwide in the U.S. Through the first three months of 2003, Insight sales declined 26 percent compared to 2002.
Perhaps this is why GM is announcing such future hybrid pickups as the Silverado and Sierra. These pickups will have an integrated starter/generator to charge a 42-Volt advanced Lead-acid battery pack found under the cabin’s rear seats. The electronics control the charging and engine restart functions and also provide current up to 20 Amps for the 100-Volt supplemental power outlets. The plugs can be used for power tools, camping equipment or other recreational gear. With large SUVs like the Hummer being popular today, this just might be what the type of hybrid the average consumer might truly want and purchase.
In California where the pressure is still on to produce no/low emission vehicles, the California Air Resources Board continues its drive for environmentally friendly cars, and will include a large “required” number for hybrids. Prior to the ARB meeting in late April, Roland Hwang, senior policy analyst for the Natural Resources Defense Council, estimated that as one of its alternatives, the Board could include 195,000 hybrid vehicles. But, an even greater allocation, 1.6 million, could be included for new models with “eco-friendly” IC engines - those “partial zero-emission (PZEV)” gasoline cars rated as super ultra-low emissions vehicles. And Mr. Hwangs’ forecasts were pointed in the right direction,. On April 24th, the Board ruled on a new requirement for 3.4 million PZEVs by 2010 and 420,000 hybrid cars, such as the Toyota prius and Honda Insight, by 2011. (BD note: Although the studies do not confirm that higher gas prices will entice consumer to buy hybrids, long term prices of gasoline in California at more than $2.10/gal. may convince some to do so. However, in other parts of the country such as the in Midwest, where gasoline is $1.40/gal., there may be little incentive.)
One thing is for sure; with all the automakers committing to a hybrid design, the consumer will be hearing more and more about hybrids. Those venturing out to buy will ultimately be the best or poorest salespersons for these vehicles. Those new hybrid buyers will be comparing their new vehicles to their former models with conventional IC engines. They will expect them to have a calendar life of 10 years without major repairs; they will expect to drive them over hills and mountains and in temperatures from 1100F to -400F. They will expect the vehicle to start and perform well even if left parked in a garage for two of three weeks. Perhaps in another five years, there will be true consumer data that will make the difference in the success of hybrids. In either case, whether the hybrids are battery-powered by Nickel-metal hydride, advanced Lead-acid or another chemistry, all chemistries will be tried by the jury of consumers who will ultimately make the decision for the winner(s).