CN102142477A - Reflective crystalline silicon solar cell module - Google Patents

Abstract

The invention relates to a reflective and low-resistance crystalline silicon solar cell module, which includes glass, EVA encapsulation layer and solar cells. A prismatic structure is arranged on the main grid line of the light-receiving surface of the solar cell, and the prismatic structure will shoot to the main grid. The light of the line is reflected, and the reflected light passes through the EVA encapsulation layer to form total reflection on the surface of glass and air, and secondly reflects to the surface of the battery that is not blocked by the main grid line. Prismatic structures are linear copper substrates with a prismatic cross-section. The outer surface of the copper substrate is electroplated to enhance the silver layer of the busbar to reflect light. The copper substrate is laminated on the main grid line through conductive silver glue. The invention can reduce the light loss and resistance loss of the solar cell assembly, reduce the optical loss by 2-4%, and increase the power of the solar cell assembly by 4-6%.

Description

A reflective crystalline silicon solar cell module

technical field

The invention relates to the technical field of solar cell components, in particular to a reflective crystal silicon solar cell component.

Background technique

Crystalline silicon solar cell modules are generally composed of dozens of solar cells connected in series and packaged with protective materials. There are several ways to improve the efficiency of solar cell modules: improving cell efficiency; reducing optical loss of components; reducing the connection resistance of solar cells. In terms of improving battery efficiency, many researchers have improved the spectrum absorption of the battery itself from the aspects of selective emitters, back electrodes, and heterojunction batteries, reducing the power loss caused by battery resistance; on the other hand, from improving the component materials including glass, The optical properties of EVA, high-transparency silicone, and the back surface, and the research work on optimizing the electrical properties of connecting ribbons, conductive tapes, junction boxes, and bypass diodes to improve component efficiency are often reported in patents and literature.

As shown in Figure 1, the front electrode grid lines of ordinary solar cells are generally composed of 2 to 4 main grid lines and 40 to 100 thin grid lines. The connection between batteries can be realized on the back of another battery. If the series resistance of the battery and the module is reduced by widening the encrypted gate line, but the increase of the shielding area will bring more optical loss.

Sunpower's backside contact cell adopts back-buried gate line technology, which reduces the front optical loss and reduces the series resistance, but the process is relatively complicated and the cost is high; in terms of reducing optical loss, Asberg Ingma et al. proposed a micro V-groove design, The included angle is 110-130°, the surface reflective layer is made of Ag, Al, Au or reflective polymer material, the V-shaped effective reflective part is located between the cell gap and the main grid line of the battery, and the reflective soldering tape passes through the planar tentacles at the left and right ends of the V-shaped and The back of the cells is connected to reduce the light loss of the module, but this design makes it difficult to weld the cells, and it is not easy to reduce the connection resistance of the cells.

Contents of the invention

The technical problem to be solved by the present invention is: to overcome the deficiencies of the prior art, and provide a reflective crystal silicon solar cell assembly, which can reduce the light loss and resistance loss of the solar cell assembly.

The technical solution adopted by the present invention to solve the technical problem is: a reflective crystalline silicon solar cell assembly, including glass, EVA encapsulation layer and solar cells, and a prismatic structure is arranged on the main grid of the light-receiving surface of the solar cells. The prismatic structure reflects the light incident on the busbar, and the reflected light passes through the EVA encapsulation layer to form total reflection on the surface of glass and air, and secondly reflects to the surface of the battery that is not blocked by the busbar.

Further, the prismatic structure is a linear copper substrate with a prismatic cross-section. The outer surface of the copper substrate is electroplated to enhance the silver layer for reflecting light of the main grid lines. The copper base material is laminated on the main grid line through conductive silver glue.

Further, the number of said busbars is 3 to 10. For example, the number of front electrode busbar lines is five. The increase in the number of front electrode busbars compared with conventional batteries reduces the series resistance of the module to a certain extent.

The beneficial effects of the present invention are: a prismatic structure is arranged on the main grid line of the light-receiving surface of the solar cell, and the prismatic structure reflects the light incident on the main grid line, and the reflected light forms total reflection on the surface of glass and air through the EVA encapsulation layer, Secondary reflection to the surface of the battery that is not blocked by the main grid line, the reflected light is absorbed by the battery and converted into electrical energy, which reduces optical loss and improves battery efficiency. The present invention adds a conductive silver glue lamination process in which the copper base material is pressed on the bottom grid line at the bottom of the copper base material through the conductive silver glue. . The invention can reduce the light loss and resistance loss of the solar cell module, reduce the optical loss by 2-4%, and increase the power of the solar cell module by 4-6%.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is a structural schematic diagram of a solar cell in the prior art;

Fig. 2 is a structural representation of a solar battery sheet in the present invention;

Fig. 3 is a schematic cross-sectional view of the reflective section grid line in the present invention;

Fig. 4 is a schematic diagram of reducing light loss at the grating line part of the reflective section after the solar cell module is packaged in the present invention;

Fig. 5 is a schematic structural view of Embodiment 1 of connecting welding strips in the present invention;

Fig. 6 is a schematic structural view of Embodiment 2 of connecting welding strips in the present invention;

Figure 7 is a schematic view of the back side of the present invention;

Among them: 1. Reflective section grid line, 2. Welding section grid line, 3. Copper substrate, 4. Silver plating layer, 5. Conductive silver glue, 6. Bottom grid line.

Detailed ways

The present invention will now be further described in conjunction with specific examples, and the following examples are intended to illustrate the present invention rather than further limit the present invention.

As shown in Figure 2 and Figure 3, a reflective crystalline silicon solar cell module includes glass, EVA encapsulation layer and solar cells. It is composed of reflective segment grid lines 1 and welded segment grid lines 2. The width of the reflective segment grid lines 1 is smaller than the width of the welded segment grid lines 2. The reflective segment grid lines 1 have a copper substrate 3 with a prismatic cross-section. On the copper substrate 3 Covering the silver plating layer 4 , the copper substrate 3 is pressed onto the bottom grid line 6 at the bottom of the copper substrate 3 through conductive silver glue.

The grid line 2 of the welding section is located at the front edge of the solar battery sheet, and the width of the grid line of the welding section is 2-5mm. The width of the grid line 1 of the reflective section is narrowed, and the width of the grid line 2 of the welding section is widened, which effectively reduces the series resistance of the battery. The cross section of the copper substrate 3 in the grid line 1 of the reflective section is prismatic, thereby forming a large aspect ratio The cross section further reduces the series resistance of the battery.

As shown in FIG. 7 , the back side of the solar cell has a back electrode busbar, and the back electrode busbar consists of a wide welding section corresponding to the front welding section grid line and a narrow grid section connected to the wide welding section and extending to the middle of the back.

As shown in Figure 4, a prismatic structure is arranged on the main grid line of the light-receiving surface of the solar cell, and the prismatic structure reflects the light incident on the main grid line, and the reflected light forms total reflection on the surface of glass and air through the EVA packaging layer. The secondary reflection is to the surface of the battery that is not blocked by the main grid line, and the reflected light is absorbed by the battery and converted into electrical energy, which reduces optical loss and improves battery efficiency.

As shown in Figure 5, a kind of connecting ribbon used for connecting the solar cells in the reflective crystalline silicon solar cell module in series, embodiment 1: has 5 front welding sections and 5 back welding sections, the front welding sections The width is greater than the width of the back welding section, and the adjacent front welding sections are connected to each other. The width of a single front welding section is 2-5 mm, and the width of a single back welding section is 0.1-0.8 mm. The front welding sections of the connecting ribbons are connected to each other, and multiple welding points are connected to each other and connected in parallel through a single ribbon itself, which improves the connection stability and makes the processing of the ribbons more convenient.

As shown in Figure 6, a kind of connecting ribbon used to connect the solar cells of the reflective crystal silicon solar cell module in series, embodiment two: it has 5 front welding sections and 5 back welding sections, the width of the front welding sections Greater than the width of the rear welded segments, adjacent front welded segments are separated from each other. The width of a single front welding section is 2-5mm, and the width of a single back welding section is 0.1-0.8mm.

The manufacturing process of the solar cell module in the present invention is: after the P-type polysilicon wafer is cleaned, acid-textured, phosphorus-diffused to form a PN junction, and anti-reflection film is plated by PECVD, the front electrode busbar line and the aluminum back field are printed and sintered. Make good electrical contact. Overlap the conductive silver glue 5 on the bottom grid line 6 of the reflective segment grid line 1, press the prismatic copper substrate 3 with the silver plated layer 4 on the conductive silver glue 5 and solidify, form a grid with a reflective segment Line 1 of the solar cell. Use connecting ribbons to connect the welding section of the front electrode busbar of the solar cell with the middle narrowing section of the back electrode busbar of another solar cell in series, and connect a certain number of solar cells in series according to the needs and typesetting them with EVA , glass and other packaging materials are made into solar cell modules that can be used for outdoor power generation.

As mentioned above, the present invention can reduce the light loss and resistance loss of the solar cell module at the same time, reduce the optical loss by 2-4%, and increase the power of the solar cell module by 4-6%.

Inspired by the above-mentioned ideal embodiment according to the present invention, through the above-mentioned description content, relevant workers can make various changes and modifications within the scope of not departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, but must be determined according to the scope of the claims.

Claims (5)

1. A reflective crystalline silicon solar cell assembly, comprising glass, EVA encapsulation layer and solar cells, is characterized in that: a prismatic structure is configured on the main grid of the light-receiving surface of the solar cell, and the prismatic structure will shoot to the main grid. The light reflected by the grid line, the reflected light passes through the EVA encapsulation layer to form total reflection on the surface of glass and air, and secondly reflects to the surface of the battery that is not blocked by the main grid line. 2 . A reflective crystalline silicon solar cell module according to claim 1 , wherein the prismatic structure is a linear copper substrate with a prismatic cross-section. 3 . 3. A reflective crystalline silicon solar cell module according to claim 2, characterized in that: the outer surface of the copper substrate is plated with a silver layer to enhance the light reflection of the main grid lines. 4. A reflective and low-resistance crystalline silicon solar cell module according to claim 2 or 3, characterized in that the copper substrate is bonded to the main grid line by conductive silver glue. 5 . A reflective and low-resistance crystalline silicon solar cell module according to claim 1 , wherein the number of said main grid lines is 3 to 10. 6 .

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