Technology Photovoltaic Modules | Solaria

Photovoltaic Modules

A photovoltaic solar energy system is composed of photovoltaic panels integrated by a group of photovoltaic cells produced from semi conductor materials. When a photovoltaic panel is exposed to light or heat, the energy is transmitted through the photons to the semi conductor, freeing the electrons from their atoms. The flow produced by these electrons creates a Direct Current (“DC”).

When the modules/systems are connected to the network, the Direct Current generated may: (i) be directly used; (ii) be stored in a battery; or (iii) be transformed into Alternating Current (“AC”) through an inverter. On the contrary to DC, the AC can be used to supply ordinary domestic apparatus. Normally production costs and prices are expressed in watts produced when sun light is maximum, that is, peak watts (Wp).

The semi conductor used most frequently is the crystalline silicon, which is available in two basic forms: Mono-crystalline and poly-crystalline silicon. The difference between these forms basically lies in the size of the crystals inside each of the structures, which at the same time generate different electrical characteristics when exposed to the light.

The photovoltaic solar energy systems can be connected to a transmission and distribution network (“on-grid”) of electricity putting the electricity produced by the photovoltaic installation into this system. They are generally installed on commercial and residential roofs, or on the ground in areas which receive a lot of sunlight, as part of larger solar energy installations. They can also be used without being connected to the network (“off-grid”) to supply electricity to isolated areas where a network connection is not possible.

The Company produces three series of photovoltaic modules (5M Series, 6M Series and 6P Series) and various types of panels in each series. The Solaria modules are from 145 Wp to 230 Wp with regards to power and use both poly-crystalline and mono-crystalline solar cells. These products are produced according to Standard specifications to be used in installations connected to the electricity network and for their use in solar energy systems not connected to a residential, commercial and industrial network.

Below there is a brief summary of the main stages of the production process:

• Classification of solar cells and quality control before production. Firstly, a series of quality control checks are made on each solar cell supplied, classifying each one according to its ability to produce energy. These quality controls are done on completely automatic classification machines. This has two functions: (i) firstly, defective cells are eliminated from the production process and returned to the supplier to be replaced; (ii) secondly given that the maximum power of each “chain” of cells is conditioned by the individual capacity of the weakest cell in the chain, we ensure that those "chains" are only formed with solar cells with similar power through the classification system, and so guarantee an efficient use of their inventory.
• Assembly of chains and matrixes. Solar cells with similar capacity are grouped together in “chains” and are connected by metallic conductor bands. This assembly process is completely automated and uses infra red lamps to detect possible failures in the welding. Once the cells are interconnected, various high definition cameras, able to detect microscopic impurities, do a computerised inspection of the surface of each of the “chains”. After that, a robotic arm puts the matrix in a highly transparent hardened glass panel covered by a film sealed with Ethylene-Vinyl-Acetate (EVA).
• Interconnection and isolation. Once a complete matrix is assembled on a glass panel, the “chains” that form the matrix are interconnected and the external connections are prepared. Then, an additional layer of EVA sealing film is used and a sheet of Tedlar-Polyester-EVA (TPE) over the matrix to protect the unit from the harmful effects of the ultraviolet rays.
• Laminate. At this stage the panels are sealed using heat in a totally automatic laminating unit. The laminating units create a pneumatic vacuum inside of the module to achieve a better sealing, being able to handle both standard and non standard modules as complete glass modules.
• Electrical tests and solar simulation. The matrix of sealed solar cells is fixed to an anodised aluminium structure that is used to make handling easier and the installation of the modules to improve their resistance to weather conditions. Then the unit is subjected to an electrical safety test to guarantee, for example, that there are no short circuits which could cause an electrical discharged in the module structure. Each completed panel is then sent to an additional solar simulation stage to measure its electrical production in diverse situations. The result of this process is registered and every module is labelled with its serial number and electrical characteristics.
• Quality controls after production. Finally, a series of quality control inspectors pass every module through detailed controls that include more than 30 different characteristics for the product.