captive electrolyte battery
A battery having an immobilized electrolyte (gelled or absorbed in a material).
cathode
The negative pole or electrode of an electrolytic cell, vacuum tube, etc.; where electrons enter (current leaves) the system; the opposite of an anode.
cathodic protection
A method of preventing oxidation of the exposed metal in structures by imposing a small electrical voltage between the structure and the ground.
cell (battery)
A single unit of an electrochemical device capable of producing direct voltage by converting chemical energy into electrical energy.
A battery usually consists of several cells electrically connected together to produce higher voltages. Sometimes the terms cell and battery are used interchangeably.
cell barrier
A very thin region of static electric charge along the interface of the positive and negative layers in a photovoltaic cell.
The barrier inhibits the movement of electrons from one layer to the other, so that higher-energy electrons from one side diffuse preferentially through it in one direction, creating a current and thus a voltage across the cell; also called depletion zone or space charge.
cell junction
The area of immediate contact between two layers (positive and negative) of a photovoltaic cell.
The junction lies at the center of the cell barrier or depletion zone.
charge
The process of adding electrical energy to a battery.
charge carrier
A free and mobile conduction electron or hole in a semiconductor.
charge controller
A component of a photovoltaic system that controls the flow of current to and from the battery to protect it from over-charge and over-discharge.
The charge controller may also indicate the system operational status.
charge factor
A number representing the time in hours during which a battery can be charged at a constant current without damage to the battery.
Usually expressed in relation to the total battery capacity; for example, C/5 indicates a charge factor of 5 hours. Related to charge rate.
charge rate
The current applied to a cell or battery to restore its available capacity.
This rate is commonly normalized by a charge control device with respect to the rated capacity of the cell or battery.
chemical vapor deposition; CVD
A method of depositing thin semiconductor films used to make certain types of photovoltaic devices.
With this method, a substrate is exposed to one or more vaporized compounds, one or more of which contain desirable constituents.
A chemical reaction is initiated, at or near the substrate surface, to produce the desired material that will condense on the substrate.
cleavage of lateral epitaxial films for transfer; CLEFT
A process for making inexpensive Gallium Arsenide (GaAs) photovoltaic cells in which a thin film of GaAs is grown on top of a thick, single-crystal GaAs (or other suitable material) substrate and then is cleaved from the substrate and incorporated into a cell, allowing the substrate to be reused to grow more thin-film GaAs.
cloud enhancement
The increase in solar intensity caused by reflected irradiance (sending forth radiant light) from nearby clouds.
combined collector
A photovoltaic device or module that provides useful heat energy in addition to electricity.
—The information for the entries in this unit were compiled primarily from data
provided in the following source:
"U.S. Department of Energy, Energy Efficiency and Renewable Energy"
consisting of definitions of many important terms having to do with electricity,
power generation, concentrating solar power (CSP), solar heating, solar lighting,
and solar electricity, also known as photovoltaic (PV).
Information was also compiled from the
Academic Press Dictionary of Science and Technology; Edited by Christopher Morris;
Academic Press; Harcourt Brace Jovanovich, Publishers; New York; 1992;
as well as,
McGraw-Hill Dictionary of Scientific and Technical Terms, 4th edition;
Sybil P. Parker, editor in chief; McGraw-Hill, Inc.; 1989.
Index of additional Scientific and Technological Topics.
