Cells specific energy

Fig. 13.47. Discharge curve for advanced prototype electric vehicle cell demonstrating 95 W h kg-1 cell-specific energy. (Reprinted from S. R. Ovshinsky, S. K. Dhar, S. Venkatesan, D. A. Corrigan, A. Holland, M. A. Fetcenko, and P. R. Gifford, Ovonic Nickel Metal Hydride Technology for Consumer and Electric Vehicle Batteries-A Review and Update," in Batteries for Portable Applications and Electric Vehicles, C. F. Holmes and A. R. Landgrebe, eds., Electrochemical Society Proc. PV97-18, p. 706, Fig. 1, 1997. Reproduced by permission of The Electrochemical Society, Inc.)...

Additive Specific Capacity, Ah kg (2 V cell) Specific Energy, Wh kg (12 V battery) Positive Mass Utilization (%) ... 

Figure 3.2 Impact of material properties (negative and positive electrodes) on cell-specific energy. Star indicates a LiCo02/graphite example. Reprinted with permission from Ref. 3.

Ethylene glycol (EG, C2H6O2) is ubiquitously used in the automotive industry as an engine coolant, and hence a distribution infrastructure already exists. Also, EG has a crossover current density roughly half that of methanol [69]. However, PEFC performance with EG is still relatively low, with a fuel cell specific energy density about 20-40% less than that of the same fuel cell utilizing methanol. Additionally, EG has been shown to rapidly degrade PEFC elecfiolyte material, which obviously limits its potential PEFC applications. 

Table 1. Specific Energies and Energy Densities of Carbon-Zinc Cells ...

Li—Al/FeS cells have demonstrated good performance under EV driving profiles and have deUvered a specific energy of 115 Wh/kg for advanced cell designs. Cycle life expectancy for these cells is projected to be about 400 deep discharge cycles (63). This system shows considerable promise for use as a practical EV battery. 

Cell type Cell reaction Standard potential (V) Terminal Capacity voltage, (Ah kg 1) Actio (V) Specific energy (Wh kg 1 )... 

Figure 17. Specific energies and energy densities of rechargeable cells. Prepared from data kindly provided by Fujifilm Celltech Co., Ltd. 342],...

A sodium-sulfur cell is one of the more startling batteries (Fig. 12.23). It has liquid reactants (sodium and sulfur) and a solid electrolyte (a porous aluminum oxide ceramic) it must operate at a temperature of about 320°C and it is highly dangerous in case of breakage. Because sodium has a low density, these cells have a very high specific energy. Their most common application is to power electric... 

Tellurium has been tested as a cathode material for use in conjunction with an anode made of alkali metal, primarily lithium, in power sources with a high specific energy and power [99], The theoretical specific energy for Li/Te pair is 612 Wh kg High-temperature (470 °C) cells with Li, Te, and eutectic (LiF-LiCl-Lil) electrolyte in the molten state, or with more convenient, albeit more resistive, paste-type electrolytes, have been tested in the laboratory. Similar layouts have been proposed for utilizing the Li/Se pair (theoretic cal specific energy 1,210 W h kg ) with the cell ingredients in the molten state (365 C) or with paste electrolyte at a lower temperature. 

The DMFC is the most attractive type of fuel cell as a powerplant for electric vehicles and as a portable power source, because methanol is a liquid fuel with values for the specific energy and energy density being about equal to half those for liquid hydrocarbon fuels (gasoline and diesel fuel). 

The other important factor in cell design optimization is the specific energy consumption, es, defined as ... 

Specific Energy—The actual energy per unit mass deposited per unit volume in a small target, such as the cell or cell nucleus, as the result of one or more energy-depositing events. This is a stochastic quantity as opposed to the average value over a large number of instance (i.e., the absorbed dose). 

The process operates at current densities of about 1 kA/m2 and unit cell voltage of 1.5 V. The specific energy consumption is about 2 kWh/kg NaOH. Under the influence of the electric gradient the H + and OH ions emerge on opposite faces of the membrane. Bipolar membrane electrodialysis is being developed by several companies, e.g. WSI Technologies Inc. [270] and Aquatech Systems [129,275,276], Typical product specification ranges for the ICI electrodialysis process is summarized in Table 19. 

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