Nickel sealed sinter plate cells

Nickel Cadmium Sealed Sinter Plate Cells... 

Figure 51.1 InfluetKeof temperature on capacity of SAFT sealed nickel-cadmium sintered plate VB type button cells (Courtesy of...

Lower cost and lower weight cylindrical cells have been made using plastic bound or pasted actwe material pressed into a metal screen. Tliese cells suffer slightly in utilization at high rates compared to a sintered-plate cylindrical cell, but they may be adequate for most applications. Tlie effect of temperature and discharge rate on the capacity of sealed nickel-cadmium cells is illustrated in Figure 8 and Table 3. 

Cell construction is mainly confined to two types, using either pocket plate electrodes (vented cells) or sintered , bonded or fibre plate electrodes (vented and sealed cells). In the former, the active materials are retained within pockets of finely perforated nickel-plated sheet steel which are interlocked to form a plate. Positive and negative plates are then interleaved with insulating spacers placed between them. In sintered plate electrodes, a porous sintered nickel mass is formed and the active materials are distributed within the pores. In sintered plate vented cells, cellulose or other membrane materials are used in combination with a woven nylon separator. In sealed or recombining cells, special nylon separators are used which permit rapid oxygen diffusion through the electrolyte layer. 

Sealed nickel-cadmium cells with mass plate elee-trodes have an ampere hour effieieney of approximately 72%, while those with sintered eleetrodes have approximately 84% effieieney at about 20°C. (The effeet of temperature will be diseussed later.) For this reason the charging factor for mass plate eells is 1.4 and for sintered plates 1.2 therefore to fully eharge a fully discharged cell, either 40% (1.4) or 20% (1.2) more eapaeity than has been withdrawn must be put baek into the cell. 

Performance characteristics of sealed lithium—molybdenum disulphide cells are compared with those sealed cylindrieal sintered plate nickel-cadmium batteries in Table 9.15. 

Figure 10.14 The construction of a cylindrical nickel/ cadmium battery. Key A, seal By positive terminal C, cell lid D, connection to positive plate E, cell case Fy positive plate G, separator H, sintered metal foil Iy negative paste Jy connection to negative plate. Diagram supplied by Berec Ltd.

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