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.

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.