In electricity, a cell is a fundamental electrical power supply. It's a device that converts stored chemical energy directly into electrical energy. This happens through chemical reactions that create a flow of electrical charge, enabling positive charges to move from the positive terminal to the negative terminal through an external circuit. Think of a battery – a battery is actually a collection of multiple cells working together.
How Cells Generate Electricity
The process involves the movement of ions (charged particles) within the cell. Different types of cells utilize various chemical reactions, but the basic principle remains consistent: chemical energy is transformed into electrical potential energy, which drives the current.
- Examples: Common types of cells include:
- Galvanic cells: These are the most common type, such as those found in everyday batteries. They use spontaneous chemical reactions to generate electricity.
- Electrolytic cells: These require an external electrical source to drive non-spontaneous chemical reactions. They are used in processes like electrolysis.
- Fuel cells: These continuously convert the chemical energy of a fuel (like hydrogen) and an oxidant (like oxygen) directly into electricity. They don't have a limited chemical supply like batteries. [Source: https://afdc.energy.gov/vehicles/how-do-fuel-cell-electric-cars-work, https://www.energy.gov/eere/fuelcells/fuel-cells]
- Solar cells (Photovoltaic cells): These are non-mechanical devices that convert sunlight directly into electricity through the photovoltaic effect. [Source: https://www.eia.gov/energyexplained/solar/photovoltaics-and-electricity.php]
Key Characteristics of Electrical Cells
- Electrochemical Cell: A cell is fundamentally an electrochemical cell; it uses chemical reactions to generate or utilize electrical energy. [Source: https://en.wikipedia.org/wiki/Electrochemical_cell]
- EMF and Internal Resistance: Every cell has an electromotive force (EMF), which represents the maximum potential difference it can provide, and internal resistance, which reduces the actual voltage delivered. [Source: https://isaacphysics.org/concepts/cp_electrical_cell]
- Unit Structure: The cell is the basic building block for generating electrical current using methods other than moving a conductor within a magnetic field. [Source: https://www.britannica.com/technology/cell-electronics]
Practical Applications
Cells are essential components in countless devices:
- Portable electronics (phones, laptops)
- Vehicles (fuel cell electric vehicles, hybrid cars)
- Medical devices
- Remote sensors and monitoring equipment
