Analysis of Solar Cell Crystalline Silicon Photovoltaic Module Packaging (Process Control)

Start with the discussion of process control, identify the key points in the process of component packaging, and focus on control to ensure the performance and reliability of the components.

I have been engaged in the packaging of photovoltaic modules for many years. I have experienced numerous thorns, bumps, flowers, and applause along the way. When I look back, I still vividly look back. From the initial ignorance of solar photovoltaic packaging knowledge, to a little knowledge, to the arbitrary, and finally to each One-step control of cautiousness. Each step of change is a lesson learned, and every step of growth has paid a heavy price.

This article will discuss the process control (the next part will start from the site management), identify the key points in the component packaging process, and thus focus on control to ensure the performance and reliability of the components.

The summary of key control points is summarized as: virtual, plastic, and loss.

(I) "Two False"

Welds may cause numerous problems, such as affecting the package power, resulting in hot spots, open circuit, arcing, resulting in excessive late use attenuation. The author believes that there are two ways to judge the virtual weld:

"Virtual 1" means that the cell sheet is blank and the busbars are virtually connected. How to determine the battery welding? The author believes that there are many ways to introduce several common methods. For battery welding quality, generally judged in two ways: first, through the naked eye to determine directly: the appearance of the virtual weld is not in contact with the position, the middle gap; second, through the tool to determine: the battery will be welded Go to the pull machine and observe the pull value.

General manufacturers require that the positive pull force is greater than 1.5N/mm, and the back pull force is greater than 3N/mm (depending on the plant). The prerequisite for stability is to record and change materials, temperature, and personnel changes. Monitoring, so as not to cause batch fluctuations, affecting the quality of welding. For the judgment of virtual connection of the bus bar, it is generally judged by the naked eye to see if the contact is firm (weld welding, no gap between the bus bars, etc.). Some factories perform spot welding operations while welding, and then control them through mutual inspection. The author believes that the best way is to improve the staff by changing the movement methods (such as press welding, pressure welding, soldering, etc.).

"Virtual 2" refers to the virtual connection between junction box terminals. At present, there are two wiring modes for junction box and bus bar: embedded and soldered. In the operation of the embedded terminal box, if the employee does not operate properly (pseudo contact or contact area is too small), the busbar and the socket do not match; or the component is rain immersed in the installation site, the box water, resulting in wiring Corrosion of terminals.

Both of these phenomena will cause the series resistance to increase, causing the junction box to burn out. In the welded junction box, some junction box manufacturers have less tin on the terminals, and the employees are directly welding for the sake of convenience and efficiency, which is a very big challenge for the 25-year warranty period.

(b) "Two glues"

"Glue 1" refers to the degree of cross-linking and peel strength. EVA film plays an important role in the quality and life of solar cells. In a sense, the lifetime of solar panels is determined by EVA. The quality of EVA depends on its formulation and modification technology (it is recommended to use plastic film produced by Dachang as much as possible). The degree of cross-linking should be controlled at about 85%; peel strength: glass/film greater than 30N/cm, TPT/film greater than 20N/cm.

"Glue 2" refers to a sealant, and the sealant includes a sealant and an encapsulant. Its role will not be described in detail, but there are two points that need to be controlled by the craftsman. First, it is monitored whether or not the rubber workers are executed according to the SOP. (Because some employees will tend to reduce the amount of glue to ensure the cleanliness of the component surface. However, this operation will cause gaps in the glass and aluminum frame, and will not achieve a sealing effect). Second, verify the sealant's stability, aging, fluidity, adhesion and its compatibility with the back (not all sealants can easily contact the backplane). Therefore, when materials are changed, it must be matched. For the potting glue, it is necessary to monitor the ratio of the two glues. Although most factories have already used potting machines, they cannot always ensure the accuracy of their proportions. Improper mixing will lead to two extreme results: Potting glue quickly cures or does not cure. Both of the results are unwilling to be seen by the managers and will affect the reliability of the components in the later period.

(c) "Two losses"

"Loss" refers to the loss of tiles, which can be divided into "recovering the tiles after the package test" and "reducing the use of tiles during use." The loss of the packaging directly affects the direct income of the enterprise, and the loss of the process will indirectly affect the reputation of the company (affecting the customer's direct income). How to reduce the loss of two kinds of tiles not only imposes higher requirements on the production enterprises (some companies seek for temporary benefits, and relax standards in process control and material selection), but also impose high requirements on installation engineering companies. (Installer professional knowledge training, installation personnel quality improvement, etc.) The author classifies the problems that affect loss watts and summarizes the factors that affect the loss watts.

To sum up, to ensure the long-term benefits of power plants for 25 years, we must start with the details and strengthen the control and control of quality control points in the process of encapsulating photovoltaic modules so as to ensure the core competitiveness of our products in the increasingly fierce photovoltaic competition! The above points of view are merely an introduction, and I hope that more colleagues who are interested in the packaging of photovoltaic modules can express their views, exchange ideas, and improve together. (The author is Executive Director of Hanghao Solar Energy Technology Co., Ltd.)

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