56
|
What is meaning of the Ah rating of cell?
|
|
The Ah rating of cell indicates its discharge rate.
|
57
|
Describe the factors to be affecting the capacity of the cell.
|
|
The capacity of cell is affected
by
- Temperature
- Discharge rate
- Density of electrode
- Quantity of active material
|
58
|
Describe the effect of density of electrolyte on the cell capacity.
|
|
As the density of electrolyte increases, the cell capacity also
increases.
|
59
|
Describe the effect of temperature on the capacity of the secondary cell.
|
|
High temperature
- Chemical reaction takes place very fast.
- The resistance of the acid decreases.
- The capacity of the cell increases as the temperature increases however it is not advisable to work cell above 400 C.
Low temperature
- Chemical reaction takes place very slowly.
- Chemical reaction between acid and terminal pots, lead alloy grid.
- The resistance of the acid increases.
- The capacity of the cell decreases with decrease in the temperature.
|
60
|
State the specific gravity of the electrolyte during charging and
discharging of lead acid cell.
|
|
The specific gravity of the charged lead acid cell is 1.21 whereas it
is 1.18 during discharging.
|
61
|
What is meaning of the sulphation?
|
|
Sulphation
- If the cell is not fully charged periodically, the lead sulphate
formed during discharging which is not converted back into PbO2
and Pb.
- There will result in reduction of PbSO4 which is deposited
on the plates. This is called as sulphation.
- The sulphation is possible if the cell is overcharged or left
uncharged for long time.
|
62
|
Describe the effect of sulphation on the cell performance.
|
|
The internal resistance of the cell increases due to sulphation. This
will reduce its efficiency and capacity.
|
63
|
How to resolve the sulphation
problem in the cell?
|
|
The problem of the sulphation is resolved by successive overcharge.
The cell gets two consecutive charges without discharge.
|
64
|
Describe the different types of alkaline battery.
|
|
Types of alkaline battery
- Nickel – Iron ( Edison )
- Nickel – Cadmium ( NIFE )
|
65
|
Describe the advantages and disadvantages of Edison battery.
|
|
Advantages
- Lighter in weight
- Compact construction
- High mechanical strength
- Requires less quantity of electrolyte as compared to lead – acid
battery
- Withstand against rapid charging and discharging
- Electrolyte corrosion liquid does not occur.
- Electrolyte does not deteriorate even if battery is left discharged
for long time.
Disadvantages
- Initial high cost
- Low watt hour efficiency and ampere hour efficiency as compared to
lead acid battery.
|
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