An electrical cell, often called an electrochemical cell, is a device that converts chemical energy into electrical energy or, conversely, uses supplied electricity to drive chemical reactions. In generating mode a cell can generate electricity, producing a potential difference between two terminals; in reverse it can be used for processes such as electrolysis or electroplating. A battery is a collection of one or more cells combined to increase voltage or capacity.
Structure and operation
Typical cells contain two electrodes (anode and cathode), an electrolyte that carries ions, and often a separator or membrane to prevent shorting while allowing ionic flow. Chemical redox reactions at the electrodes move electrons through an external circuit and ions through the electrolyte. The difference in chemical potential between electrode materials determines the open-circuit voltage; internal resistance, electrode surface area and reaction rates influence practical performance.
Types and examples
- Primary cells – single-use, non-rechargeable types such as alkaline and zinc–carbon.
- Secondary cells – rechargeable cells including lead–acid, nickel-based and lithium-ion chemistries.
- Fuel cells – convert fuel and oxidant continuously to electricity while supplied.
- Specialized cells – reference, concentration or research cells used for measurement and calibration.
For practical consumer use many cells are assembled into a single package; see common descriptions of battery assemblies for more context.
Applications, performance and safety
Cells power portable electronics, electric vehicles, backup systems and industrial processes. Key performance parameters include energy and power density, cycle life for rechargeable cells, charge/discharge efficiency and self-discharge. Safety topics cover proper charging, avoiding overtemperature conditions and containment of leaks; some chemistries require careful management to reduce risks such as short circuits or thermal runaway. End-of-life handling and recycling are important to recover materials and reduce environmental impact.
Laboratory and historical notes
Cells are used in laboratories to study reaction kinetics, electrode behavior and analytical methods; controlled experiments and electrochemical methods help characterize materials. Measurement and diagnostic approaches are commonly applied to evaluate capacity, internal resistance and degradation mechanisms (measurement techniques).