
Nickel-cadmium batteries have an
exceptionally good lifetime and cycle
life because their plates are not
gradually weakened by corrosion, as
the structural component of the plate
is steel. The active material of the
plate is not structural, only electrical.
The alkaline electrolyte does not react
with steel, which means that the
supporting structure of the block
battery stays intact and unchanged
for the life of the battery. There is no
corrosion and no risk of “sudden
death”.
In contrast, the lead plate of a lead
acid battery is both the structure and
the active material and this leads to
shedding of the positive plate material
and eventual structural collapse.
7
4.1
Plate assembly
The nickel-cadmium cell consists
of two groups of plates, the positive
containing nickel hydroxide and
the negative containing cadmium
hydroxide.
The active materials of the Saft
Nife pocket plate block battery are
retained in pockets formed from steel
strips double perforated by a
patented process.
These pockets are mechanically
linked together, cut to the size
corresponding to the plate width and
compressed to the final plate
dimension. This process leads to a
component which is not only
mechanically very strong but also
retains its active material within
a steel containment which promotes
conductivity and minimizes electrode
swelling.
These plates are then welded to a
current carrying bus bar assembly
which further ensures the mechanical
and electrical stability of the product.
BlockBat 3/11/98 10:11 Page 10
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