A few tips to help you know more about PV modules

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1. Photovoltaic modules: the foundation of solar power generation

Solar cell module = solar panel:
Due to the low output voltage of a single solar cell, coupled with the unencapsulated cells due to the environmental impact of the electrodes are easily fall off. Therefore, a certain number of single cells must be sealed into by using series and parallel connections.

PV module 1

The PV module is located between the PV cell and the PV system and is the final product of the PV manufacturing industry.

2. The preparation of PV modules consists of two major steps: cell interconnection and lamination.

①Cell interconnection: The standard number of cells for PV modules is 60 or 72, corresponding to 10 or 12 copper wires as PV busbars to connect them, and 6 groups are interconnected as one PV module.

②Lamination: After the cell interconnection, it is generally necessary to follow the order of tempered glass, adhesive film, cell, and back sheet from bottom to top. After the way of encapsulation together. The back sheet and tempered glass encapsulate the cells and adhesive film inside and are protected by aluminum edges and silicone sealing edges. After the lamination process, the service life of PV modules can be significantly increased and the environmental resistance and mechanical properties can be significantly optimized.


3. There are currently 2 technological directions for PV cells, which are bifacial modules and half-sheet packages.

①Bifacial modules: PV modules that use bifacial cells. The feature is that both the front and back sides have the ability to generate electricity. When the sun shines, some of the light is reflected by the surrounding environment to the back of the module. Bifacial modules have the ability to collect this portion of light energy, thereby increasing power generation.

Obviously, bifacial cells can generate more power than traditional single-sided designs. This can effectively reduce the average cost of power generation. Accordingly, the production process of bifacial cells is also more complicated. The backside cannot use conventional back sheet which is opaque, and the superimposed other production processes lead to slightly higher costs.

2019-2030 Change in market share of single/dual-sided PV modules 3

②Half-cell package: The mainstream package mode at present. It means that the cell is cut into two halves of the same size along the direction perpendicular to the main grid line of the cell. The current generated by a PV cell in the process of power generation is related to the cell area. When the half cells are connected in series, the resistance of individual positive and negative circuits remains unchanged. And the power loss of a single circuit is reduced to 1/4 of the original one, thus reducing the overall power loss of the module. It also reduces the negative impact of module heating on power generation capacity.

PV module half cut diagram 4

4. Several factors affect the power output of PV modules

① Hot spot effect
A partially shaded solar cell module will be used as a load to consume the energy generated by other solar cell modules with light. The shaded solar cell module will become hot at this time, which is the hot spot effect.
This effect can seriously damage the solar cell. Some of the energy produced by the illuminated solar cells may be consumed by the shaded cells. What causes the hot spot effect may be just a piece of bird droppings.
In order to prevent the solar cell from suffering damage due to the hot spot effect. It is better to connect a bypass diode in parallel between the positive and negative terminals of the solar cell module. To avoid the energy generated by the lighted module being consumed by the shaded module. When the hot spot effect is severe, the bypass diode may be broken and the module will be burned, as shown in the figure below:


②PID effect
Hidden cracking is a defect of the cell. Due to the own characteristics of the crystal structure, crystalline silicon cells are very prone to rupture. The process of crystalline silicon module production is long, and many links may cause hidden cracking of cells. In recent years, crystalline silicon module manufacturers have been moving towards thinner and thinner crystalline silicon cells in order to reduce costs. This has reduced the ability of the cells to prevent mechanical damage.

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