How lead acid battery works | Working principle animation

Summary

This video explains the working of a lead-acid battery, a widely used power source in electric vehicles. It covers the battery’s components, including the anode, cathode, electrolyte, and separator. The discharging process involves the reaction of sulfuric acid with the plates, producing lead sulfate and releasing electrons to power a load. The charging process reverses this, restoring sulfuric acid and converting lead sulfate back into lead. Through these cycles, the electrolyte's sulfuric acid concentration fluctuates, ensuring the battery operates efficiently. The video provides a clear understanding of both the chemical reactions and electrical processes involved in a lead-acid battery’s functioning.

Takeaways

• 😀 Lead-acid batteries are widely used in electric vehicles.
• 😀 The battery consists of an anode (spongy lead), cathode (lead peroxide), electrolyte (diluted sulfuric acid), and separator (Absorbent Glass Mat - AGM).
• 😀 During discharging, sulfuric acid breaks into hydrogen ions and sulfate ions.
• 😀 The sulfate ions move to the anode, react with lead to form lead sulfate, and release electrons.
• 😀 The electrons travel through the external circuit to light up the load and reach the cathode.
• 😀 At the cathode, hydrogen ions and sulfate ions react with lead peroxide to form lead sulfate and water.
• 😀 During discharging, sulfuric acid concentration in the electrolyte decreases, and water is produced as a byproduct.
• 😀 In the charging process, lead sulfate deposits convert back into lead and lead peroxide.
• 😀 Water formed during discharging breaks into hydrogen and oxide ions during charging.
• 😀 Sulfuric acid concentration in the electrolyte increases during charging as lead sulfate is converted back into sulfuric acid.

Q & A

What are the main components of a lead-acid battery cell?

The main components of a lead-acid battery cell are the anode made of spongy lead (Pb), the cathode made of lead peroxide (PbO2), the electrolyte which is diluted sulfuric acid, and the separator which is made of absorbent glass mat (AGM).

How does a lead-acid battery discharge?

During discharge, when a load is connected to the battery, sulfuric acid in the electrolyte breaks into positive hydrogen ions and negative sulfate ions. The sulfate ions move towards the anode, react with lead to form lead sulfate, and release electrons. These electrons travel through the external circuit, light up the load, and then reach the cathode, where the sulfate ions react with lead peroxide to form lead sulfate and water.

What happens at the anode during the discharge process of a lead-acid battery?

At the anode during discharge, the sulfate ions react with lead to form lead sulfate, releasing electrons in the process.

What is the byproduct of the discharge reaction in a lead-acid battery?

The byproduct of the discharge reaction in a lead-acid battery is water, produced when the sulfate ions react with lead peroxide at the cathode.

What are the main reactions occurring during the discharge of a lead-acid battery?

During discharge, sulfuric acid in the electrolyte breaks into hydrogen ions and sulfate ions. At the anode, lead reacts with sulfate to form lead sulfate, while at the cathode, lead peroxide reacts with sulfate and hydrogen ions to form lead sulfate and water.

What changes occur in the electrolyte during the discharge process?

During discharge, the sulfuric acid in the electrolyte is consumed, and the electrolyte loses sulfuric acid while gaining water as a result of the chemical reactions.

How does a lead-acid battery charge?

During charging, a charger is connected to the battery, and current flows from the charger. The lead sulfate deposits formed during discharge are reversed. At the cathode, oxide ions react with lead sulfate to form lead peroxide, releasing sulfate and electrons. The electrons move toward the anode, where lead sulfate is converted back to lead and sulfate ions, restoring sulfuric acid in the electrolyte.

What happens at the cathode during the charging process?

At the cathode during charging, oxide ions react with lead sulfate to form lead peroxide, releasing sulfate and two electrons in the process.

What is the change in the electrolyte during the charging process?

During charging, water in the electrolyte breaks into hydrogen ions and oxide ions. The electrolyte's sulfuric acid concentration increases as lead sulfate is converted back to lead and sulfate ions, and the reactions at both the anode and cathode restore sulfuric acid.

What is the total cell reaction during charging and discharging of a lead-acid battery?

During discharging, the total cell reaction is the conversion of sulfuric acid into lead sulfate at the anode and lead peroxide at the cathode, with water as a byproduct. During charging, the lead sulfate is converted back to lead at the anode and lead peroxide at the cathode, restoring sulfuric acid to the electrolyte.