Fuel cell-battery hybrids

Another important potential appHcation for fuel cells is in transportation (qv). Buses and cars powered by fuel cells or fuel cell—battery hybrids are being developed in North America and in Europe to meet 2ero-emission legislation introduced in California. The most promising type of fuel cell for this appHcation is the SPEC, which uses platinum-on-carbon electrodes attached to a soHd polymeric electrolyte. 

Fuel cell hybrid cars are not a new concept. In the early 1970s, K. Kordesch modified a 1961 Austin A-40 two-door, four-passenger sedan to an air-hydrogen fuel cell/battery hybrid car (71). This vehicle used a 6-kW alkaline fuel cell in conjunction with lead acid batteries, and operated on hydrogen carried in compressed gas cylinders mounted on the roof The car was operated on public roads for three years and about 21,000 km. 

Fig. 13.32. Series fuel cell-battery hybrid power train model. The two-way energy flow between the drive motor and electric bus indicates the potential for regenerative braking. (Reprinted with permission from Research and Development of Proton-Exchange-Membrane (PEM) Fuel Cell System for Transportation Applications, Phase I. Final Report, prepared for the U.S. Dept, of Energy by General Motors, 1996, Fig. 3.5.2.1.)...

The transportation sector is clearly the sector where a transition to sustainable energy sources is most difficult. For the past several decades, hopes were placed in battery-based electric vehicles, but it has taken long time to reach the technical goals for battery performance, and the economic goals that would make a purely battery-operated vehicle with suitable range become economically acceptable have not yet been reached. As a consequence, automobile manufacturers have lowered the expectations to battery-driven vehicles and instead hope that fuel cell vehicles will be able to meet both technical and cost goals. The analysis in Chapter 4 indicates that this may not be the best approach, because fuel cell-battery hybrids may well turn out to be a better solution, due to the complementary advantages of the two sys-... 

DaimlerChrysler Unveiled a fuel-cell/battery hybrid concept vehicle based on the Jeep Commanders with near-zero tailpipe emissions and twice the fuel efficiency of a standard SUV. 

Fadel A and Zhou B (2011), An experimental and analytical comparison study of power management methodologies of fuel cell-battery hybrid vehicles,/oMmo/ of Power Sources, 196,3271-3279. 

Schematic of a fuel cell/battery hybrid configuration.

Pesaran, A., Zolot, M., Markel, T., and Wipke, K. (2004) Fuel cell/battery hybrids an overview of energy storage hybridization in fuel cell vehicles. Presented at the 9th Ulm Electrochemical Talks, Ulm, May 2004. 

Gao, L., Jiang, Z., and Dougal, R.A. (2004) An actively controlled fuel cell/battery hybrid to meet pulsed power demands. /. Power Sources, 130, 202-207. 

Gao, W. (2005) Performance comparison of a fuel cell-battery hybrid powertrain and a fuel cell-ultracapacitor hybrid powertrain. IEEE Trans. Veh. Technol,... 

Power Management and Design Optimization of Fuel Cell/Battery Hybrid System... 

Jiang ZH, Dougal RA (2006) A compact digitally controlled fuel cell/battery hybrid power source. IEEE Trans Ind Electron 53 1094-1104. doi 10.1109/TIE.2006.878324... 

Small fuel cells that provide power at ratings below 1000 watts, are being introduced into and groomed for application areas such as portable power sources, mobile power sources, remote or unattended power sources, and propulsion power for small, off-the-road vehicles. These existing and candidate applications may include power systems that are fuel-cell-only, fuel-cell/battery hybrids, and fuel-cell/solar/battery hybrids, depending on the nature of the system s requirements. Representative examples of such applications are illustrated in Table 43.1. 

Catalysts are an important part of metal-air batteries and have been investigated for use in lithium-thionyl chloride cells also. Metal-air batteries are very similar to fuel cells and have been called fuel cell-battery hybrids because one of the electroactive materials, oxygen, does not require storage. 

There are many other aspects of recent FCV development that are worth commenting on, including a trend towards greater hybridization with batteries, which can make an FCV more responsive, and save money as a less powerful fuel cell might be required as a result. There have also been improvements in cold start-up (Honda is at the forefront here), and in the development of slim-line fuel cell systems that can fit into a car s chassis. Ju et al. (2005) have unveiled a control algorithm for active power distribution in a fuel cell/battery hybrid power source to improve system efficiency and battery life with load following capability. 

Ju R A, An J H, Lee J K and Lee S H (2005) DSP-Based Actively Controlled Fuel Cell/Battery Hybrid DMFC System, 3rd European PEFC Forum, Poster 417. 

---