Before diving in deep cycle battery corrosion we want to define Corrosion process.
Corrosion or the oxidation of the deep cycle battery’s grid (where corrosion
mostly happens) occurs when two
dissimilar materials in the same electrolyte are connected electronically
and reactions occur at each material ,result in
causing plate growth and eventually
destroys the deep cycle battery’s grid.
In our case we take about positive electrode
that consist of active positive material
PbO2 , Pb grid material and acid – H2SO4
act as electrolyte.
One
of the factors that limit the cycle life of the deep cycle battery is corrosion process that is taking place
between the positive grid material and the positive active. Corrosion leads to
grid oxidation that support the active
positive material result in grid ruin
which it either transmit or receive the current from or to
grid and it will proceed continuously during float
charge and shorten the lifetime of the deep cycle battery and then leads to
end of the service life to the situation that the current conductor (lead) is
almost no longer available , (figure 1).
This
phenomenon is also called premature capacity loss; this reaction not only
decreases the positive grid conductivity but also consumes the water , and
leads to the growth of the positive plates , the grid wires do not have the
mechanical force due to the degree of corrosion. Corrosion lead to potential
differences of the positive and the negative electrode, result in self-discharge and faint performances of deep
cycle battery .
Deep
Cycle Battery Corrosion Reasons
1-
Continuous operation at high temperatures
particularly above 55C may reduce life as a result of an increase
in the rate of deep cycle battery’s corrosion
2- Excessive overcharging
leads to increasing positive grid corrosion, and this is manifested as
‘‘growth’’ or expansion of the grid.
3-Moisture and dirt on
top of and between cells permits stray intercell currents, resulting in
corrosion through electrolysis.
4-
Denser acid tends to form
at the bottom of the deep cycle battery. especially
in the space
below the plates, this
can cause increased
corrosion.
5-
The repeated charging and discharging of the deep cycle battery shortens the
battery life through heat generation and corrosion.
Industrial
Esteems to Resist
Deep Cycle Battery Corrosion
1-Tubular
plate types have a good corrosion resistance.
2-
The pure lead provides a high corrosion resistance and an extremely long
service life.
3-
Use of pure or special alloy lead result in corrosion resistant increasing.
4- A
light coating of petroleum jelly is used Intercell to prevent corrosion .
Recommendations
to Preserve A deep Cycle Battery
1-
Keeping the deep cycle battery clean and
dry, particularly top of the battery will minimize corrosion of cell post
connectors and steel trays.
2- Keep the batteries from rain water that could cause
corrosion on the terminals of the batteries
3- A
coating of no-oxide anti-corrosive grease on terminals will usually prevent
corrosion.
4-A
low charge current is desirable to minimize overcharge, grid corrosion
associated with overcharge.
5-It
is important to control the charge to maintain
the morphology of the electrode, to prevent a rise in the temperature,
particularly to a point where deleterious side reactions (corrosion) take place.
6-
Overfilling must be avoided because the resultant overflow
of acid electrolyte will cause tray corrosion, ground paths, and loss of cell
capacity.