1. Basic Structure:
- A car battery consists of multiple cells, typically six, connected in series. Each cell contains positive and negative plates immersed in an electrolyte solution (usually a mixture of sulfuric acid and water).
2. Chemical Reaction:
- When the battery is connected to a circuit, a chemical reaction occurs between the lead plates and the electrolyte.
- During discharge, the lead plates undergo a transformation. The negative plates (made of pure lead) become oxidized, releasing electrons, while the positive plates (made of lead dioxide) are reduced, accepting electrons.
3. Electron Flow and Circuit Completion:
- The chemical reactions in the battery generate a flow of electrons from the negative plate (anode) to the positive plate (cathode) through the external circuit. This electron flow constitutes an electric current that can power the car's electrical systems, such as the starter motor, lights, and electronic control units.
4. Lead Sulfate Formation:
- As the battery discharges, lead sulfate crystals form on both the positive and negative plates. This process reduces the amount of active material available for the chemical reactions and limits the battery's capacity to deliver current.
5. Recharging:
- To replenish the battery's stored energy, it needs to be recharged. This is done by connecting the battery to a charging system, which reverses the chemical reactions.
- During charging, an external power source (such as an alternator in the vehicle) provides an electric current that causes the lead sulfate crystals to break down and the lead plates to return to their original states.
6. Voltage and Capacity:
- Each cell in a car battery produces around 2 volts, so a 12-volt battery consists of six cells connected in series.
- The battery's capacity is determined by the amount of active material on the plates and electrolyte strength. It is typically measured in amp-hours (Ah) and indicates how much current the battery can deliver over a certain period.
7. Maintenance:
- Car batteries require periodic maintenance to ensure optimal performance and longevity. This may include checking electrolyte levels, cleaning terminals to prevent corrosion, and avoiding deep discharges.
By undergoing these electrochemical processes, a car battery stores chemical energy and converts it into electrical energy when needed to power the vehicle's electrical systems.
