Scientists at the Institute of Transportation Studies at the University of California-Davis have published a report that may temper enthusiasm for plug-in hybrids. The report entitled “Batteries for Plug-in Hybrid Electric Vehicles: Goals and the State of Technology circa 2008” compares several types of PHEV batteries used in the automotive market based on five criteria. Researchers looked at power, energy, longevity, safety and cost when compiling data for this report.
The academic institute tried to dampen enthusiasm or criticism of the report by stating that it was not meant as a conclusive study. Consumers, manufacturers and legislators should bypass these modest claims to review earnestly several conclusions. An overarching conclusion of the report is that PHEV battery developments by Toyota and other companies may need to be more modest to balance technological advancement with financial viability. The report’s authors cited blended conversion systems and the Prius NiMH prototype as examples of the baby steps approach to PHEV batteries.
Additional conclusions covered the issue of meeting industry standards for batteries as well as a preference for Li-ion batteries over NiMH technology. The report states that no battery tested at UC-Davis met the United States Advanced Battery Consortium (USABC) standards for PHEV designs. USABC’s criteria were appropriated by the ITS researchers to demonstrate that there is a web of tradeoffs needed in current PHEV batteries. This conclusion feeds into the determination that Li-ion batteries are able to meet USABC standards in a more cost-efficient manner than NiMH in the current market.
Readers interested in getting down to basics should look at the report’s discussion of seven different Li-ion batteries. The most promising battery on the market uses a manganese titanium combination that is restricted to research at this point. Car owners would have access to high power and energy levels if this battery chemistry is able to pass muster. Most of the chart is filled with batteries like lithium ion phosphate and lithium cobalt oxide products that reside within the moderate approach recommended by the ITS. This document reflects the uncertain future of PHEV batteries and should be seen as background information for dialogue on clean technologies.
