Technology
Lab to test electric vehicle batteries New facility is part of DOE program under electric vehicle act to push development of near-term battery options as fossil fuel alternatives
After dedication ceremonies at Argonne National Laboratory near Chicago late last month, the National Battery Test Laboratory (NBTL) opened as a central facility for testing and evaluating new and improved batteries developed for electric vehicles and for stationary load-leveling service. It will thus have a direct role in what has been a somewhat lackluster U.S. effort in electric vehicle development. NBTL is a direct result of the Electric & Hybrid Vehicle Research, Development & Demonstration Act of 1976. Between $40 million and $50 million has been authorized under the act for support of battery R&D. Much of this R&D is being conducted at Argonne in cooperation with commercial battery makers. Featured at the NBTL dedication were two electric passenger vehicles using lead/acid batteries. One was a converted Ford Futura and the other a specialty vehicle being developed by Sears Roebuck & Co. Neither car is intended for the immediate market; both are operated as test vehicles. Although there is some consideration being given the long-term development of batteries, most of the emphasis at Argonne and NBTL is on near-term developments. This is the result of the electric vehicle act and a considerable effort expanded by the Department of Energy to develop all kinds of alternative energy sources to liquid fuels. At the recent Intersociety Energy Conversion Engineering Conference in Boston, Maurice J. Katz and Kurt W. Klunder, program officers at DOE headquarters in Washington, D.C., gave an overview of the DOE electric vehicle battery program. The DOE program is divided into two parts, near and long term. The near-term program involves development and design of full-size vehicle
DOE's National Battery Test laboratory at Argonne has space for simultaneous testing of 50 batteries in either series or parallel circuits
batteries (20 to 30 kwh) utilizing three electrochemical systems: nickel/zinc, nickel/iron, and improved lead/acid batteries. DOE currently supports work at Argonne and at eight commercial battery makers on the three systems. Each of the commercial developers is expected to deliver its first 20-kwh battery late in 1979 or early in 1980. These will be tested at NBTL, and the best one will power a fleet of 10,000 test vehicles authorized by the electric vehicle act between now and 1985. According to Katz and Klunder, the nickel/zinc battery offers the most promise at present. Its principal drawback is a very limited deep-cycle capability, and it can perform for only about 100 cycles. At least 500 cycles are necessary for commercial success. The nickel/iron batteries are not generally available in large sizes and are probably the most expensive near-term batteries. Both of the nickel-containing batteries perform better than any others in the near-term program. However, that is no guarantee that they will win the battery sweepstakes. Even if they meet the performance requirements, costs may be prohibitive. The present leaders in the test program appear to be the familiar lead/acid batteries in improved form, and there are indications that further improvements may be considerable. Lead/acid batteries are more adapt-
able than others, and, if the weight problem can be solved, they may power the first fleet of electric vehicles under the electric vehicle act in the 1980's. In the long-term program conducted by DOE, any battery in principle can be considered a candidate for development. However, preliminary screening has pared the serious candidates down to four. These are lithium/metal sulfide, sodium/sulfur, zinc/chlorine, and metal/air systems. Depending on one's degree of optimism, these offer promise beyond the near-term batteries. But there is less than universal confidence that the long-term program will produce any real breakthroughs in battery technology. The ultimate purpose of the electric vehicle act and the corresponding battery programs is to reduce consumption of liquid fossil fuels in general, and oil imports in particular. The alternate fuel in this case is electricity, which is admittedly not the cheapest fuel available. There is occasional doubt expressed outside DOE that the electric vehicle program can ever be justified on purely economic grounds. Proponents of the program argue that secure supply is the real issue and that any kind of energy, petroleum included, will cost more in the future. The lack of enthusiasm for electric vehicles in the U.S. may be due to a Sept. 10, 1979 C&EN
27
lack of publicity and promotion, but it is also manifest outside the U.S. In its second annual review of electric vehicles around the world, a group from Jet Propulsion Laboratory ( JPL) has described the status as of the end of 1978. One of the major findings is that electric vehicles are used to any extent only in England and Japan, and there only because of special local conditions. In England, home milk deliveries have been made for many years with electric vehicles. In Japan, a publisher operates a similar fleet of delivery trucks. In both cases the overriding consideration is for quiet operation in a populated region in the early morning hours. The only U.S. electric vehicle fleet of major size is that operated by the Postal Service. Auto and truck makers perpetually express interest in electric vehicles, but there is, in fact, only limited development in progress. This is usually attributed to the lack of a perceived market. Even so, DOE is exerting great pressure to develop electric vehicles, market or no market, and the lack of any organization to service them notwithstanding. At present, the typical electric vehicle maker in the U.S. is a small company that has been in business for three or four years and makes only a few units per year. The vehicles are usually small passenger cars and/or delivery vans. According to the J P L survey, the manufacturers are "machine oriented" and few of them have a real appreciation of potential markets or eventual electric vehicle requirements. Not everyone agrees with that assessment but it does seem to be widespread. Most electric vehicle development so far has been an attempt to adapt the conventional gasoline-powered vehicle to battery power, rather than starting from scratch. This has been the approach of American Motors in adapting the Jeep to electric drive for the Postal Service, which now has about 350 vehicles in operation. This is the largest electric vehicle fleet in the U.S. and provides operating data for DOE. Elsewhere in the world, the experience with electric vehicles closely parallels that in the U.S. In England the milk delivery vans have been operating for about 40 years and remain cost-effective, according to operators. However, the market appears to be limited to about 1500 vehicles per year, a demand easily satisfied by three manufacturers. Japan probably has the largest electric vehicle program in the R&D stage. This program includes small cars and vans and some 30,000-lb passenger buses. D 28
C&EN Sept. 10, 1979
Coal cuts energy use in metal electrowinning
be extracted in large amounts from aqueous solutions by electrowinning. Electrowinning is already an important source of much U.S. chromium, cobalt, nickel, copper, zinc, and cadmium. Energy savings arise from the low voltage needed to oxidize carbon to carbon dioxide in water solution compared with the voltage for oxidation of water to oxygen. In terms of standardized laboratory conditions, the reversible thermodynamic potential for carbon oxidation is only 0.21 volt, compared to 1.23 volts for water. The number of amperes required for a given weight of metal remains the same because the same number of coulombs is needed. Volts times amperes is watts, however, which is power, and lowering the voltage reduces power consumption. With the assistance of senior chemical engineering student Larry Veneziano, Coughlin and Farooque plated copper from a solution of copper sulfate in dilute sulfuric acid at 60° C using platinum gauze anodes and cathodes. A magnetic stirring bar was used to stir a slurry of pulverized North Dakota lignite coal. Purity of deposited copper was more than 99% as measured by atomic absorption spectroscopy. Use of lignite or presence of its ash in the electrolyte did not seem to affect purity. In addition to platinum gauze, graphite rods and felt also were successful as anodes. Copper plates performed well as alternate cathodes.
Smelting metals at the expense of oxidizing carbon is as old as the Bronze Age. Something newer is electrolytic reduction of metals in a cell that uses coal or lignite as reducing agent in a medium no hotter than warm water. Chemical engineers at the University of Connecticut, Storrs, who developed the coal-based electrowinning process, say the technique cuts electric power consumption two thirds compared with customary electrolytic refining based on parallel oxidation of water alone [Nature, 280, 666 (1979)]. Even when alternative use of the coal or lignite to generate electricity is considered, the engineers say, power use is half that of usual methods. Chemical engineering professor Robert W. Coughlin and postdoctoral student Mohammad Farooque developed coal-based electrowinning of metals out of their process of coalassisted electrolysis of water—a kind of room-temperature coal gasification (C&EN, June 25, page 33). In this process, hydrogen is produced at the cathode and carbon dioxide containing 3 to 7% carbon monoxide at the anode. The Connecticut investigators cite chromium, manganese, cobalt, nickel, copper, zinc, gallium, cadmium, indium, and thallium as metals that can
Coal-metal redox couple saves energy by reducing voltage Cathode gas outlet Anode gas outlet
\>
Supporting electrolyte
Cathode Platinum anode Fritted-glass separator
Coal slurry Anode:
C + 2H 2 0 — -
Cathode: 2 C u 2 + 4e~
C0 2
- 2Cu
4hl·
4e~
