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1.1. General description
1.1.1. Operation principle of
vented Ni-Cd cells
The electrochemistry concept of
the batteries is to supply energy to
electrical and electronic products.
Chemical energy stored in a
battery is converted into electric
current when the battery
is discharged. This electric current
is produced directly by chemical
reactions that occur within
the battery.
The nickel-cadmium cell is an
electrochemical system in which
the electrodes containing the
active materials undergo changes
in oxido-reduction state without
any change in physical state.
The active materials are
submerged in alkaline electrolyte.
They remain in solid state and
do not dissolve during the oxido-
reduction process. As a result,
the electrodes are long-lived,
since no chemical mechanism
exists that might cause the loss
of active materials.
When a battery is charged
or discharged, the hydroxide
ions (OH) are transferred from
one electrode to the other via
the electrolyte. The alkaline
electrolyte, a liquid solution of
potassium hydroxide (KOH) and
additives, provides the means of
transport for the ions.
It does not participate in the
electrochemical reaction. Its role
in the operation being passive,
the electrolyte is only remotely
affected by the state of charge
of the nickel-cadmium battery.
During overcharge, the water
contained in the electrolyte is
decomposed into oxygen and
hydrogen.
In a low maintenance battery,
a significant amount of these
gases recombines in the battery,
thus reducing water consumption.
The remaining amount leaves
the cells through the hydraulic
system. Consequently, the
electrolyte level is reduced after
a certain number of charging
cycles and periodic topping-up of
the battery with water becomes
necessary (chapter 6.2.).
1. Characteristics of STM MR-MRE
monoblocks
3
Summary of Contents for STM 5-100
Page 1: ...Technical manual installation operation and maintenance for Ni Cd STM MR MRE monoblocks type ...
Page 23: ...Appendix 1 20 Monoblock STM 5 100 MR G RD equipped Positive left Filling right ...
Page 24: ...21 Appendix 2 Monoblock STM 5 100 MRE G RD equipped Positive left Filling right ...
Page 25: ...Appendix 3 22 Monoblock STM 5 140 MR G RD equipped Positive left Filling right ...
Page 26: ...Appendix 4 23 Monoblock STM 5 140 MR D RG equipped Positive right Filling left ...