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16/03/2020

Batteries Interview Question Answer - 4


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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