E
Efficiency [%]
The ratio of power output of a Photovoltaic cell to the incident power from the sun or simulated sun sources under specified standard insolation conditions.
Efficiency of conversion [%]
Relationship between the electric energy produced and the incident solar energy on a PV device.
Electric contacts
Conductor elements which establish or cut off the continuity of an electric circuit. In the PV cell contacts are realized with high conductive material (i.e. silver) and with a grid configuration formed by fingers and busbars, so as not to obscure the cell.
Electric current
The rate at which electricity flows through an electrical conductor, usually measured in amperes (amps).
Electricity
Energy resulting from the flow of charge particles, such as electrons or ions.
Electric load [W]
The instantaneous electric power (the consumed energy) required by any electric user. It is measured in Watt (W).
Electrochemical accumulator
Device to convert chemical energy into electric energy through an oxidation-reduction process (redox).
See also: Accumulator batteries.
Electrolyte
The fluid used in batteries as the transport medium for positively and
negatively charged ions.
Electrolyte density
In a battery, it's the relationship between the weight and the volume of the electrolyte. The electrolyte density shows the battery SOC and it is expressed in gr/cm³. It is measured by a float densimeter.
Electronical grade silicon
Highly pure and very expensive silicon, normally used in semiconductor industry (also called Semiconductor grade silicon).
Electrons
A negatively charged particle. The movement of electrons in an electrical conductor constitutes an electric current.
Energy
Generally measured in J (Joule); electric energy is measured in Wh (Watt-hours) and is equal to the energy provided by a device distributing one Watt of power per hour (1 Wh = 3.600 J, 1 cal = 4,186, 1 Wh = 860 cal).
Energy density
Relationship between the available energy of a battery and its volume (in Wh/cm³), or its weight (in Wh/kg).
Equalization recharge
Periodic recharge of an accumulator in order to equalize (i.e. homogenize) the battery accumulators. It is usually practised once or twice a year with the aim of bringing the battery to the “high voltage” zone (2.6÷2.7 V/el) and letting it gasificate for some hours.
EVA (ETHYLENE VINYL ACETATE)
An encapsulant used between the glass cover and the solar cells in PV modules. It is durable, transparent, resistant to corrosion, and flame retardant.
