By understanding the photovoltaic module production process and to learn which machines are involved in the production of a module, gives you the knowledge to understand the points that are delicate and fundamental for the production helping you in the choice of a reliable and high-quality product.
The assembly of photovoltaic modules consists of a series of consecutive operations that can be performed by automatic machines dedicated to optimizing the single production phases that transform the various raw material in a finished product. Thanks to more than 25 years of experience in the industry, Ecoprogetti offers photovoltaic module production lines of various levels of automation and capacities according to the requirements of each individual customer.
The production phases are:
In this first phase the various raw material used for the assembly process is being controlled and prepared. In particular, the glass is being cleaned for the following steps. With cutting machines the rolls of encapsulant and back sheet material are being cut to measure in quantities that correspond to the programmed production. Some of this equipment can be integrated into the production line according to the wished level of automation.
The photovoltaic cells are placed in a piece of equipment, called solar stringer, that interconnects the cells in a series by soldering a coated copper wire, called ribbon, on the bus bar of the cell. This delicate operation creates the string that is the basic element that creates the electrical series in the photovoltaic module. The most important parameter to check is the soldering quality. The mono and polycrystalline cells can be managed in an optimized way by our stringer machines with a reliable, constant and high-quality soldering result.
The strings of photovoltaic cells created by the stringer machine is automatically or manually positioned on the glass previously prepared with the first layer of encapsulant material. The machine that performs this operation in the PV module production line, called lay-up, can at the same time perform quality controls of the product in order to verify that the cells are intact finding possible breakages and to verify the accuracy of the soldering quality.
In order to create an electrical circuit, after positioning all strings composing the module on the glass, you proceed with the soldering of the bus ribbon which is of larger thickness than the ribbon being used for interconnecting the strings. Also, this phase can be atomized or customized according to the desired application. In a standard PV production line, this phase is performed manually.
When the electrical circuit between all strings of cells is finished the second layer of encapsulation material is being applied followed by a foil of insulating material called back-sheet. The operator brings out the terminal ribbon that will be connected in a successive step with the junction box. At this point of the production process, it is important to perform some electrical tests and possibly also an electroluminescence test in order to verify that there are no short circuits or broken photovoltaic cells inside the module because now it is still possible to correct possible failures.
During the lamination process the multi-layer sandwich composed until now is transforming into one single unit thanks to the polymerization of the encapsulating material. Laminators developed for the photovoltaic industry are the machines performing this phase. These machines work at a high level of vacuum for a certain time at a certain temperature. The setting of the temperatures and the time is being defined by the encapsulating material used. The extraction of the air is a fundamental aspect to guarantee the quality and durability of the product. The photovoltaic modules that exit from the laminator are called laminates. Production lines with a high throughput often have cooling systems installed after the laminator to permit a quick process without waiting times.
The framing phase is composed of several small steps which start with the trimming of the surplus material of encapsulant and back sheet that is left around the glass after the lamination process. The frame is applied around the PV module with tape applied directly on the laminate or silicone that is dispended directly into the channel of the aluminium frame. Machines are available for each of these steps that can also be integrated into fully automatic solutions like Ecoprogetti’s fully automatic framing island.
The last assembly phase consists of the application and the connection of the junction box. The process is done by attaching the box with a suitable silicone or glue on the back sheet of the module and by making the electrical connection between the bus ribbon prepared before the lamination and the cables of the junction box. At the inside of the box, you can find by-pass diodes that protect the photovoltaic module when operating. After finishing this operation the module is cleaned.
At the end of the assembly phases the PV module is being controlled and tested. This phase is one of the most important steps because with these tests you measure the electrical output of the module and the product gains a commercial value. The measure is being done by a LED sun simulator that is able to reproduce some specific light conditions that measure the peak power of the module according to the norms.
Normally after this test, the following operations follow:
– Insulation and dielectric rigidity test called Hi-Pot;
– Electroluminescence test to verify the construction quality;
– Labeling of the module according to the chosen classification.
At the end of this process, you obtain a photovoltaic module that is ready to be commercialized and installed on the field.
Ecoprogetti Srl offers equipment and accessories dedicated to each manufacturing step. Moreover, Ecoprogetti develops also solutions to complete turnkey lines for the manufacturing of photovoltaic modules. Our packages consent to any company to start production of high-quality modules in a very short time. The package is composed according to the requirements of the customer and can be anything from a small semi-automatic solution to a high capacity fully automatic plant.
The technicians and staff of Ecoprogetti srl is at your disposal for any clarification or specific questions about our PV production equipment and for the realization of your specific solution.