Alpha Technologies Industrial Ni-Cd Batteries Standard Range - Manual (Page 8)

8 EN-ALPHA-TMSR-001 (10/09)
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1.3 Electrode frame
The electrode frame of Alpha Ni-Cd-batteries consists of a right and a left side bar as well as the electrode edge
which are connected by welding shaping the electrode frame. The electrode frame operates as a current collector
and also seals the electrode plates. This procedure leads to an electrode design with high mechanical robustness
but also ensures a reliable service for the complete lifetime of the battery.
1.4 Separators
The separation of the electrodes is ensured by a corrugated perforated plastic (M- and L-types) or plastic grid
separator (H-types). The plastic grid separator is used for high discharge types (H-types) in order to achieve a
superior cell performance caused by a lower internal resistance, which is very typical and necessary for their
high discharge currents. The separator also ensures a large space between the electrodes, which allows free
circulation of the electrolyte and a good dissipation of the gases generated during end of charging.
1.5 Positive and negative electrode plate
The nickel-cadmium cell is composed of the positive plates containing nickel hydroxide and the negative plates
containing cadmium hydroxide. The pockets formed from a nickel plated and perforated steel tape, the so-called
pocket tape, infold strips of the active material.
The electrode strips are mechanically linked together forming the electrode plate and cut to size appropriate to the
width based on the cell type and range.
The plates then are welded or mechanically linked to the plate frame (see point 3) forming the electrodes - the
heart of the battery - and assembled to the plate block.
The basis for the extemely long useful lifetime and the very good cycle life features of the Ni-Cd pocket plate
batteries are the special plate designs whose structural components are made of steel. This prevents the
possibility of gradually deterioration by corrosion and since the alkaline electrolyte does not react with steel the
substructure of the battery remains intact for the total lifetime of the battery. Very important and unique is the
enfolding of the electrochemical active masses in the perforated nickel plated steel pockets, so that the risk of
shedding or penetration of material is very small and consequently also the risk of structural damages and of soft
short circuits is well under control.
1.0 Alpha Ni-Cd pocket plate cell, continued
Fig.1-4 Components of the Electrode plates Fig.1-5Electrode plate linkage