Electroluminescence is an optical and electrical phenomenon in which a material emits light in response to the passage of an electric current or to a strong electric field.

The typical structure of an OLED electroluminescent device is based on one or more organic semiconductor layers provided between two electrodes.

The organic materials can be very small molecules or polymers.

If we cut an electroluminescent strip vertically we will find first with the negative electrode or cathode, usually metal. Here we find the luminescent material (1) and followed by the positive electrode or anode (conductive material).This conductor would be covered with a transparent protective layer (2).The combination of electrons and holes in a material, typically a semiconductor, generates the release of the electrons energy as photons. These photons are light (3) projected and visible.

Its most important technical features are:

• They can illuminate large surfaces.
• Uniform illumination.
• Very low power consumption.
• No radiation emission.
• Very small sizes and/or flat.
• Flexible.
• Indoors and outdoors working.
• No vibration.
• There are a lot of colours.

Its most common applications are:

• Lighting panels of vehicles or aircraft.
• Keyboard panels or electronic panels.
• Displays.
• Signs and posters or billboards.
• Decoration.
• Road signs and vests.

When calculating the life of a battery it will be necessary to know the number of charge cycles that can be performed until the battery does not begin to lose its capacity.
Depending on the type of battery these charging cycles can vary, the most common being the mobile batteries, manufactured Li-Ion or Li-Po, which have a duration of between 300 and 500 charging cycles according to model and manufacturer.
Once thisE limit we will notice how the battery loses duration of operation, arriving to lose up to 25% of its capacity of load.
At this point it will be necessary to evaluate a battery change.
It should be noted that usage and charging habits can significantly affect battery life. For example, factors such as heat, charge the battery several times a day without it is almost exhausted, etc. Will be affectedits duration.
Therefore, to get the most out of the battery we must know when a full charge cycle is performed, and try to avoid misuse of charge, to increase its useful life.
A charging cycle is considered when the battery has been discharged or its 100% charge has been used.
The manufacturers advise that the charge is never made below the 58% battery, since the battery voltage would not fall so lowTo, so you could end up winning up to 4000 charge cycles.
Tips to increase the life of a battery.

• Avoid extreme heat or cold or very long applications of the device.
• Charge the battery as often as you can.
• Fully discharge the battery from time to time.
• Do not let the battery run out completely before charging.

Below is a table with theDifferent voltages (V), charge cycles (C) and battery percentage (B).

Within the wide range of batteries on the market we can differentiate two large groups, disposable batteries and rechargeable batteries.
Disposable batteries are those that only allow a single use and when they are exhausted they can not be recharged. These batteries can store their energy for years.

Rechargeable batteries are those that can be recharged once exhausted. This type is losing charge when they are storedaccording to voltage. The most common we can find them of 1.2V and 3.7V

As a last point you have to take into account that lithium batteries, Lipo, Life etc. Due to its composition, specific loaders should be used.