Electrochemical cell
There are generally two main types of electrochemical cells: primary (non-rechargeable) and secondary (rechargeable) batteries.
A galvanic cell also called a voltaic cell, is an electrochemical cell in which an electric current is generated from an oxidation-reduction reaction. The cell normally consists of two different metals (electrodes), immersed in separate containers that hold a positively or negatively charged solution. A salt bridge or porous membrane between the containers transfers charge. Energy is derived from a high-cohesive-energy metal dissolving while to a lower-energy metal is deposited, and/or from high-energy metal ions plating out while lower-energy ions go into solution. A primary or non-rechargeable battery is a galvanic cell, a secondary or rechargeable battery acts as a galvanic cell when it is discharging, as it is converting chemical energy to electrical energy. A secondary or rechargeable battery acts as an electrolytic cell when it is being charged as in this case it is converting electrical energy to chemical energy.
An electrolytic cell, is one in which a current is passed through by an external voltage, causing a chemical reaction. An electrolytic cell has three parts: a cathode, an anode (electrodes) and an electrolyte. As above electrolyte is usually a solution of water or another solvent, such as sodium chloride with dissolved ions. When an external voltage is applied to the electrodes, the ions in the electrolyte are attracted to an electrode with the opposite charge, the charge-transferring causes the chemical reaction, faradaic or redox. In the galvanic cell the chemical reaction causes electric current to flow.
An equilibrium electrochemical cell is a cell that sits in a state that is directly between the two above cell states, so nether storing chemical energy nor releasing electrical energy.
A fuel cell is considered to be a galvanic cell but because the products of the reaction are continuously removed it is one that requires a supply of reactants. It does not therefore store chemical or electrical energy but extracts electrical energy directly from a chemical reaction involving oxygen, hydrogen, electricity, heat and water.
[edit] Related articles on Designing Buildings
Featured articles and news
Noise in the built environment
BSRIA guide TG 20/2021.
17,000 people suffer conditions as a result of exposure to excessive noise at work.
Turning down the noise: Auditory health
A pervasive risk with far-reaching consequences.
UK Construction Week, London is here !
Debuting major international pavilions and much more.
Getting the most out of heat pumps and heating
How heat pumps work and how they work best.
Plumbing and heating for successful retrofit and renovation
Low temperature underfloor systems and heat pumps.
Cost-of-living crisis and home improvement plans
Starting on the right footing and top tips for projects.
Delays on construction projects
Types, mitigation and the acceleration of works.
From Chaucer to Fawlty Towers.
Electrotechnical excellence, now open for entries.
Net zero electricity grids BSRIA guide NZG 5/2024
Outlining the changes needed to transition to net zero.
CIOB Global Student Challenge 2024
Universitas Indonesia wins for second year running.
New project and cultural district described in detail.
ECA 2024 Apprentice of the Year Award
Entries open for submission until May 31.
UK gov apprenticeship funding from April 2024
Brief summary the policy paper updated in March.