Nickel-hydrogen batteries applications

J. E. Clifford and E. W. Brooman, Asessment of Nickel—Hydrogen Batteries for Terrestrial Solar Applications, SAND80-7191, Sandia National Laboratories, 1981. 

Nickel—hydrogen batteries offer long cycle life that exceeds that of other maintenance-free secondary battery systems and accordingly makes it suitable for many space applications. Three types of separator materials have been used for aerospace Ni—H2 cells— asbestos (fuel-cell-grade asbestos paper), Zircar (untreated knit ZYK-15 Zircar cloth),and nylon. 

Developed in the 1960s, it makes use of different technologies for its electrodes NiO(OH) is from nickel cadmium and H2 from fuel-cell systems. Because of its longer cycle life the main use of the nickel-hydrogen battery is in aerospace applications to replace the nickel cadmium cells. For example, the Hubble Space Telescope launched in 1990 was equipped with nickel-hydrogen cells [12]. 

Nickel-hydrogen batteries (Ni/T ) were developed in 1970 for aerospace applications. These batteries are a combination of the Ni-Cd technology (Ni electrode) and the fuel-cell technology (H2 electrode). They use nickel hydroxide as cathode active material, a hydrogen electrode as anode, and an aqueous solution of potassium hydroxide as electrolyte. Asbestos (fuel-cell grade asbestos paper) and Zircar (untreated knit ZYK-15 Zircar cloth) are used... 

Nickel and its alloys are extensively used in electrochemical applications due to its good corrosion resistance. In battery applications, nickel is used as the positive electrode in nickel-cadmium, nickel-iron, nickel-zinc, and nickel-hydrogen batteries, and as anodes in fuel cells, electrolyte cells and electro-organic syntheses . Because of the importance of nickel in battery applications, electrochemical properties of nickel have been studied for more than IOC years since 1887 when Dun and... 

This must not be confused with the nickel-hydrogen battery (NiH2 battery) used in space applications - particularly in the International Space Station (ISS) [MIL THA 03]. 

THA03] Thaller L.H., Zimmerman A.H., Overview of the design, development, and application of nickel-hydrogen batteries , NASA/TP-2003-211905,2003. 

Nickel/hydrogen batteries are closely related to the nickel/cadmium battery, since they employ the same positive electrode and the same electrolyte. They have been developed for aerospace applications and are still the number one energy storage system in many satellite projects 60. 

Of the conventional secondary systems, the nickel-iron and the vented pocket-type nickel-cadmium batteries are best with regard to cycle life and total lifetime. The nickel-hydrogen battery developed mainly for aerospace applications, has demonstrated very long cycle life under shallow depth of discharge. The lead-acid batteries do not match the performance of the best alkaline batteries. The pasted cells have the shortest life of the lead-acid cells the best cycle life is obtained with the tubular design, and the Plante design has the best lifetime. 

The present state of development of individual pressure vessel (IPV) nickel-hydrogen battery cells is that they are acceptable where not many cycles are required over life, i.e. 1000 cycles over 10 years of geosynchronous orbit applications, but are not acceptable in applications where many cycles are required, typically 30 000 over five years. In low earth orbit applications only 6000 to 10000 cycles at 80% depth of discharge can be achieved. 

Yuasa, Japan have been developing prototype nickel-hydrogen batteries for electric vehicle applications. They have claimed 200 maintenance free cycles at 100% depth of discharge. 

The development of nickel/cadmium batteries started in the beginning of the twentieth century in parallel to that of the nickel/iron battery. The latter played an important role mainly as a sturdy traction battery that reached many charge/ discharge cycles. But after World War II it gradually lost its market, mainly because of the high hydrogen evolution rate and comparatively low power efficiency. The nickel/cadmium battery, however, still has a strong market position, mainly in its sealed version as a portable power source, but also as a flooded battery in traction and stationary applications. 

Hydrogen evolution can also be prevented, and thus the unwanted secondary reactions hydrogen evolution and grid corrosion that disturb the internal oxygen cycle in lead-acid batteries, as shown in Fig. 1.25, are not present in nickel/cadmium batteries, which therefore can be hermetically sealed so that neither vapor or gas escapes from the battery. This is the reason for the market success of these batteries in the field of portable applications. 

At low temperatures and at high loads the desorption rate of the hydrogen can be limiting. For this reason, nickel/cadmium batteries may be preferred in such applications. 

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