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What is a secondary cell called? , Type | difference in primary cell

Cells that can be recharged are called secondary cells. Charge them before using them. On providing power supply to this cell, it will have Electricity Energy is stored in the form of chemical energy. When this is added to the circuit, the collected chemical energy is converted into electrical energy.

Due to which electric current starts flowing in the circuit, that is chemical The energy is slowly dissipated and has to be re-charged to be used again. The battery formed by combining such cells is called accumulator battery or secondary cell.

Example- Lead acid cells, nickel-cadmium cells, nickel-iron cells, etc. Following are the major types of secondary cells.

Lead Acid Cell

It is the most widely used secondary cell at present. Its main parts are as follows.

1. Container : It is made of rectangular sulfur containing rubber. It is a hard rubber. Acid has no effect on it. In this, the part of each cell is separate in which the positive and negative plates are kept and in this only electrolyte is filled. The mud house remains inside the container at the bottom, due to which the liquid gets accumulated by falling down due to chemical reaction.

2. Positive, Negative Plate: These are of two types-

  • Plante Plate
  • Fare Negative Plate

3. Separator: The separator is made of wood and porous rubber is also used in it. A separator is placed between each negative plate and positive plate so that a short circuit does not form between the two plates. They contain pores so that ions and electrolytes can flow during decomposition.

4. Cell Cover: The caps of the cells are made of hard rubber, so that each cell is covered with a lid. Because of this, the electrolyte does not come out. There are holes in these in which the vent plug is tightened.

5. Plate Connector: These are used to connect the plates of cells together in series. They are made from pure lead. From these the main terminals of the cells (the positive end and the negative end remain raised) are pulled out.

6. Cell Connector: The number of cells in the secondary cell is more according to its capacity. The part that connects each cell together is called a cell connector. These are also made of pure lead.

7. Sealing Compound: It is made of bitumen compound. They are used to make the joints of the battery cover acid tight, thus keeping these joints leak proof.

8. Vent Plug: The cover in the cell is made of hard PVC (rubber). It has churidar holes in which dot is attached. They are used to add water or electrolytes when needed.

9. Electrolyte: Electrolyte is prepared by mixing pure water in concentrated HDSO in a lead acid cell and with the help of this current flows in the cell. There are two types of lead acid cells which are as follows.

Flooded Lead Acid Cell

This cell consists of a container in which multiple plates are immersed in a solution of dilute sulfuric acid. Due to less reconnection (of holes and electrons) in this type of cell, the water consumption in the battery is high, due to which they emit corrosive and explosive gas when the battery is overcharged. This type of cell is used in most industrial applications.

Sealed Lead Acid Cell

In this type of cell, the reconnection process is faster, due to which the need for water in the battery is less. In this, the emission of explosive gases during charging is less because the electrolyte does not allow these gases to diffuse over the other plate. This type of battery is used in electronic equipment.


  1. in lead acid cell electrolyte has a major role. While preparing it, keep in mind that pour acid in pure water drop by drop. Don’t pour water into the acid, otherwise accidents can happen.
  2. The temperature of the electrolyte should be 27 ° C and the relative density should be 1.250 ° 0.010.
  3. Apply a layer of petroleum jelly to the terminals of the cell to prevent corrosion.

Chemical Reaction

  1. At Discharging Time

on the positive plate

PbO2+H2+H2SO4 → PbSO4 + 2H2O

on the negative plate

Pb+2+So4-2 → PbSO4
  1. At Charging Time on the positive plate
PbSO4 + SO4 + 2H2O → PbO2 + 2H2SO4

on the negative plate

PbSO4 + H2→ Pb+2 + H2SO4 

The potential of a fully charged battery ranges from 2.1 to 2.6 volts.


The rating ampere hour (Ah) of a lead acid cell is the ability to discharge ampere current. The size of the plates, the number of plates, hulls and batteries depend on the active substance used and the concentration of the electrolyte.

Nickel Iron or Edison Cell

This alkaline cell Also called. It is also called Edison cell. Like the lead acid cell, it is also a beneficial cell. Its main parts are as follows –

  1. Negative Plate
  2. Positive Plate
  3. Filler Cap
  4. Negative Terminal
  5. Positive Terminal
  6. Pin Insulator
  7. Steel Container
  8. Electrolyte

Electrolyte: It contains a solution of potassium hydroxide. To increase the efficiency of the cell, 21% KOH and some amount of lithium hydrate are also added.

money (+) Plate or electrode (anode) Ni(OH)4(nickel hydroxide) is made of.

loan plate or cathode electrode (-) FeO.

as picture (+) The positive plate is made by connecting a perforated nickel plated tube. They are usually 6 mini diameters and 110 mm in length. In these Ni(OH)4, is filled. These are then tightened into the steel frame. The negative plate is nickel plated. The oblong grooves are completely filled with fine powder of iron oxide (FeO) from the leaves. Some mercury is also added to this powder.

Separator : The positive and negative plates are separated by rubber strips to keep them separate from each other. All are kept in a container made of steel and welded from all sides. The relative density of the electrolyte is kept at 1.22.

Chemical Reaction

  1. At Charging Time
    1. Positive Plate: On oxidation, the nickel plate is converted into a higher grade nickel oxide.
    2. Negative Plate: Oxygen and hydrogen are produced during charging which carry out the processes of oxidation and reduction.
      • (+) Ni(OH) at plate electrode anode2+ 2OH, → Ni(OH)4
      • (-) Fe(OH) at the plate electrode cathode2+ 2K → Fe+2 + 2KOH
  1. At Discharging Time
    1. The positive plate (+) electrode at the anode
      • Ni(OH)4 + 2K, → Ni(OH)2 + 2KOH
    2. negative plate (-) electrode at cathode
      • Fe+2 + 20H, → Fe(OH)2

Characteristics of Nickel Iron Cell

The volume of a fully charged cell is 1.4V which becomes 1.2V on discharging. If the voltage drops below 1.15V then they are completely discharged. These positive-negative plates have good mechanical strength as they are made of steel. There is no fault in keeping them discharged.

The internal resistance of this cell is high, hence the efficiency is low. Vivab with increase in temperature as compared to lead acid cell. There is some increase in but there is a substantial increase in capacitance.

  • Storage Its life span is quite long. These are constructed for a period of up to years.
  • Temperature The battery or nickel iron cell is set for a given capacitance at room temperature 20 °C.

Differences between Lead Acid Cell and Nickel Iron Cell

The major differences between lead acid cells and nickel iron cells are as follows:

No. S. description lead acid cell Nickel Iron (Edison) Cell
1 positive plate Pbo (Land Peroxide) Nickel Hydroxide Ni ( OH )4 or nickel oxide ( NiO2 ,
2 negative plate spongy lead iron oxide
3 electrolyte Tanu H2SO4 (Sulfuric Acid) Potassium Hydroxide (KOH)
4 average emf 2.1V (Sail) 1.2V (Sail)
5 internal resistance comparatively less more than
6 relative density The decrease increases due to the formation of water. no effect
7 efficiency ampere hour 90-95 % 80% ( approx )
8 watt hour 72-80% 60% ( approx )
9 worth Nickel is less than iron sal. Lead acid is more than sal.
10 mechanical power low More
Comparison of Lead Acid Cell and Nickel Iron Cell

Uses of Secondary Cell or Battery

  • In the lighting of vehicles in the auto mobile sector
  • For self starting system in vehicles in auto mobile sector
  • In emergency light and inverter
  • in radio and telephone
  • in railway air conditioning
  • in electronic equipment

Differences between Primary and Secondary Cell

primary cell The differences between the secondary cell and the secondary cell are shown in the following table (8.4)-

S.No primary cell Secondary Cell (Battery)
1 These can be recharged ( charged. They cannot be recharged.
2 They are light in weight and can be carried anywhere comfortably. They are heavy. It is difficult to carry them from one place to another.
3 In these, the amount of current also decreases with time. They can give current for a long time at a constant voltage.
4 This cell does not need to be charged before use. They have to be charged before they can be used.
5 Their life span is very short. Their life span is long.
6 Their viva The force was less. Their viva The force is greater.
difference between primary and secondary cells

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