Difference Between Cell and Battery - Types, FAQs

This article discusses the difference between cell and battery, the difference between cell padding and cell spacing, the function of cell and battery, difference between fuel cell and battery.
Batteries are the source of electric current that is used to start an automobile. small appliances like watches, clocks, radios, and other electric machines. A group of electrochemical cells which is a device for interconverting chemical and electrical energy is called a battery. In a spontaneous chemical reaction, the energy is released which is taken by batteries to form electricity.

Figure 1 Cell

Types of Battery

1. Primary battery

Here, in these cells, electrode reaction is not reversed by flowing an external electrical current and reaction happens only once and after the completion of the reaction. It has become used and dead.

For example Dry cell and mercury cell

2. Secondary battery

Here, in these cells, electrode reactions can be reversed by flowing an external electrical current and hence can be recharged and used again and again.

For example Lead-acid storage cell and Ni-Cd cell.

Also read -

• NCERT Solutions for Class 11 Chemistry
• NCERT Solutions for Class 12 Chemistry
• NCERT Solutions for All Subjects

What is the difference between a cell and a battery?

Cell and battery difference is given below.

Selection of Electrodes

Electrodes are always classified on the basis of process and are never classified on the basis of charge or polarity. It is emphasized on the fact that greater the reduction potential, reduction takes place on that electrode, and that respective electrode acts as the cathode and vice versa independent of the nature of the cell under consideration.

Anode Negative Loss of electron or oxidation takes place

Cathode Positive Gain of electron or reduction takes place

Galvanic cells consist of two half cells that are anodic and cathodic and the cell reaction is of redox type. In a voltaic cell, oxidation takes place at the anode and reduction at the cathode in the cell. This is represented in Figure 1 which shows that the zinc rod is treated as an anode that is immersed in ZnSO₄ solution and the copper rod is treated as a cathode that is immersed in CuSO₄ solution.

Working principle of galvanic cell

In a galvanic cell, the anode and cathode metal strip is dipped in electrolyte and the oxidation and reduction reaction takes place simultaneously. In a galvanic cell, there is a voltage difference between the electrolyte and metal. When the two metals are joined with the wire, the current flow due to the potential difference between metal and electrolyte in an electrochemical cell.

Anode

The reactive metal zinc is treated as an anode that is dipped in a salt solution of zinc sulphate. The zinc atom will move in the salt solution to form zinc ion Zn²⁺.

The reaction is shown below.

This will not allow the extra zinc ion to go in the solution.

The positive charge will move near the rod and the extra positive charge of the solution will move around the negative potential difference formed between the electrode and the electrolyte. In anode oxidation reaction takes place. During oxidation reaction electrons are released.

Cathode: Some metals like (Cu, Ag. Au etc.,) and many more are found to have the opposite propensity when placed in contact with their aqueous ions then the ions from the solution will get deposited on the metal rod in the electrochemical cell.

The following equilibrium will be established .

So the rod will have deficiency of electron (positive charge). The extra negative charge will move around the positively charged rod and form a double layer. This electrical double layer is established and the potential difference is formed between the rod and the solution known as electrode potential. At cathode, reduction occurs. In reduction, gain of electrons take place.

Their electrode potential can be represented by E_Cu²⁺.

Also, students can refer,

• NCERT solutions for Class 12 Chemistry Chapter 3 Electrochemistry
• NCERT Exemplar Class 12 Chemistry Solutions Chapter 3 Electrochemistry
• NCERT notes Class 12 Chemistry Chapter 3 Electrochemistry

Oxidation half reaction:

(loss of electrons)

Reduction half reaction:

(gain of electrons)

Overall reaction:

Salt Bridge:

The electrolyte in the salt bridge should be such that the speed of its cation equals the speed of its anion in the electric field. The salt bridge connects the solution of the two half cells by completing the circuit. The salt bridge helps to maintain the electric neutrality of the solution to form a continuous flow of current. Mainly KNO₃ or NH₄ NO₃ is used to form salt bridge. The removal of salt bridge leads to voltage drop to zero.

Also check-

• NCERT Exemplar Class 11th Chemistry Solutions
• NCERT Exemplar Class 12th Chemistry Solutions
• NCERT Exemplar Solutions for All Subjects

NCERT Chemistry Notes:

• NCERT Notes Class 11th Chemistry
• NCERT Notes Class 12th Chemistry
• NCERT Notes For All Subjects