Over the past years, producing photovoltaic solar modules has literally been booming, inter alia due to the increased demand on environmentally sound energy production. The direct conversion of sunlight into electric current by means of photovoltaic solar modules is entirely emission-free, and no risks for humans and the environment are almost involved. For example, complete roofs of new buildings are therefore recently overlaid with solar modules, and even “solar power plants” are built. Due to the technical development of photovoltaics, using solar modules more and more becomes efficient even in more unfavourable latitudes such as Middle Europe and Northern America so that especially in these regions there is a great demand. Due to the continuous progress of the efficiency of solar modules due to technical further development on the one hand as well as increasing costs of energy production with other energy carriers as fossil fuels or nuclear energy, photovoltaic power generation becomes more and more competitive.
It is apparent that the success of solar modules in economic competition with other energy carriers depends on the costs of producing and mounting the solar modules.
Typically, solar modules consist of a plurality of solar cells based on semiconductor technique, which cells are interconnected to large-scale solar panels. A typical solar module typically has a glass plate on its side facing the sun, and a transparent plastics layer on the rear side, in which layer the solar cells are embedded. Typically, the rear side of the solar module is covered with a weather-resistant plastics compound foil, for example polyvinyl fluoride and polyester. The mono- or polycrystalline solar cells are electrically interconnected to each other by means of small solder wires. Typically, the solar module is furthermore mounted in a metal profile frame for fixing and stiffening the compound. Therefore, a solar module basically is a two-dimensional entity, similar to a glass plate.
Typically, solar modules have thin flexible conductor bands on the side facing away from the sun. These bands are mostly made of copper and vertically protrude from the rear side of the solar module. These flexible conductor bands are very sensitive and therefore difficult to contact. Additionally, a mechanical charge for fixing an electrical connector is also difficult because of the disk-like form of the solar module. Therefore, a special kind of electrical connectors has evolved for such solar modules, which kind is called connection box or connection and junction box. Typically, the connection and junction box is glued on the rearward surface of the solar module, and has electrical connection devices inside for contacting the flexible flat conductor bands of the solar module. Furthermore, if needed, the connection and junction box has an apparatus for connecting an electrical connection cable, which is connected with the flexible flat conductor band of the solar module by means of the connection and junction box for conducting the electrical current generated by the solar module.
Furthermore, several solar modules are typically operated in series connection, wherein a so-called bypass diode or free-wheeling diode is anti-parallel connected to each module. Inside the connection and junction box, the free-wheeling diode is connected to the electrical connection device. If a module is shaded or does not produce electricity because of a defect, this module would lower the power of the solar modules in series connection or even suffers damage without bypass diode. This is avoided by the bypass diode, because the current flows through the diode and is sustained.
It is apparent that due to the mechanical conditions, particularly the form of the solar module and the sensitiveness of the flexible flat conductor bands, a number of difficulties occur, when constructing the connection and junction box. Up to now, connection boxes are known, which are put over the flexible flat conductor bands. When doing so, the flexible flat conductor band is manually bent and contacted by means of a contact clamp or a soldered connection. The connection box is closed in a further process step. It is apparent that mounting such connection devices or connection boxes respectively is laborious, and is badly suited for automated mass production.
An electrical connection and junction box for a solar module is known from DE 103 58 140 B4, which box has a guiding arrangement at its lower side. The thin conductor band is guided in this guiding arrangement in lateral direction with low slackness in order to avoid buckling or folding the conductor bands, when inserting into the clamp apparatus. At this, it is disadvantageous that the conductor band has to be threaded into the narrow guiding arrangement, and the clamping force of the clamp arrangement may nevertheless be relatively low to be able to insert the thin conductor band into the clamp arrangement.
After all this, there is need for improvements in this regard, due to the high pressure to innovate in producing solar modules.