A back contact solar cell and photovoltaic module

Abstract

This utility model discloses a back-contact solar cell and a photovoltaic module. The back-contact solar cell may include: a cell structure and an insulating structure. The cell structure includes: a cell body, with alternating positive and negative fine grid lines arranged on the back side of the cell body; an insulating structure spaced between the positive and negative fine grid lines; the insulating structure includes: a light-conversion insulating component and a high-reflectivity insulating component, the high-reflectivity insulating component being fixed to the side of the light-conversion insulating component; the light-conversion insulating component in the insulating structure is fixed and covers the insulating positions of the positive and negative fine grid lines. This back-contact solar cell can prevent discoloration of the insulating structure caused by laser spots, thus ensuring the appearance consistency of the photovoltaic module constructed from the back-contact solar cell.

Description

Technical Field

[0001] This utility model relates to a back-contact solar cell and a photovoltaic module. Background Technology

[0002] For back-contact solar cells, the positive and negative grid lines are alternately arranged on the back of the cell to prevent the front from being blocked, effectively improving photoelectric conversion efficiency. In the manufacturing process of photovoltaic modules using back-contact solar cells, it is generally necessary to use insulating adhesive to separate the solder ribbon connecting the positive grid line to the negative grid line, and to use insulating adhesive to separate the solder ribbon connecting the negative grid line to the positive grid line. However, during laser welding of the solder ribbon and grid lines (positive or negative grid lines), because the solder ribbon and insulating adhesive are close together, if the laser spot shifts, it can cause localized heating of the insulating adhesive, leading to localized discoloration and affecting the uniformity of the photovoltaic module's appearance. Utility Model Content

[0003] In view of this, the present invention provides a back-contact solar cell and a photovoltaic module. The back-contact solar cell is provided with an insulating structure including a light conversion insulating component and a high-reflectivity insulating component. The high-reflectivity insulating component can reflect laser light, which can prevent the laser spot from causing discoloration of the insulating structure, thereby ensuring the appearance consistency of the photovoltaic module constructed from the back-contact solar cell.

[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0005] In a first aspect, embodiments of the present invention provide a back-contact solar cell, comprising: a cell structure and multiple insulating structures, wherein...

[0006] The battery structure includes: a battery body, and alternating positive and negative fine grid lines on the back of the battery body;

[0007] Multiple insulating structures are spaced apart on the positive electrode fine grid line and the negative electrode fine grid line;

[0008] The insulation structure includes: a light conversion insulation component and a high-reflectivity insulation component, wherein the high-reflectivity insulation component is fixed to the side of the light conversion insulation component;

[0009] Each of the aforementioned insulating structures includes a light-conversion insulating element that is fixed and covers part or all of the insulating positions of the positive electrode fine grid line and part or all of the insulating positions of the negative electrode fine grid line.

[0010] Secondly, this utility model provides a photovoltaic module, including: a back-contact solar cell provided in any of the above embodiments or a cell segmented from a back-contact solar cell provided in any of the above embodiments.

[0011] The first aspect of the above-mentioned utility model has the following advantages or beneficial effects:

[0012] The back-contact solar cell provided in this embodiment includes an insulating structure comprising a light-conversion insulating component and a high-reflectivity insulating component. The high-reflectivity insulating component is fixed to the side of the light-conversion insulating component. When the light-conversion insulating component is fixed and covers part or all of the insulation positions of the positive electrode fine grid lines and part or all of the insulation positions of the negative electrode fine grid lines, electrical contact between the positive electrode fine grid lines and the negative electrode solder strip can be avoided. During the laser welding and fixing of the positive and negative electrode solder strips to the cell body, because the high-reflectivity insulating component is fixed to the side of the light-conversion insulating component and is closer to the laser spot, it can prevent the laser spot from affecting the light-conversion insulating component. Furthermore, even if the laser spot shifts during laser welding, the high-reflectivity insulating component can reflect the laser, preventing the laser from affecting the light-conversion insulating component and avoiding discoloration of the insulating structure, thus ensuring the appearance consistency of the photovoltaic module formed based on this back-contact solar cell.

[0013] Furthermore, the light conversion insulator included in this insulation structure reduces light reflection and increases the amount of light reaching the battery body, thereby improving the light utilization rate of the back-contact solar cell. Moreover, this light conversion insulator can convert wavelengths of light that cannot be utilized by the battery body into wavelengths that can be utilized by the battery body, further increasing the amount of light reaching the battery body and thus further improving the light utilization rate of the back-contact solar cell. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the back structure of the first type of existing back-contact solar cell;

[0015] Figure 2 This is a schematic diagram of the back structure of the second type of existing back-contact solar cell;

[0016] Figure 3 This is a partial back structure schematic diagram of the first structure of a back-contact solar cell provided according to an embodiment of the present utility model;

[0017] Figure 4 This is a partial back structure schematic diagram of the second structure of a back-contact solar cell according to an embodiment of the present invention;

[0018] Figure 5 This is a partial back structure schematic diagram of the third structure of a back-contact solar cell provided according to an embodiment of the present invention;

[0019] Figure 6This is a partial back structure schematic diagram of the fourth structure of a back-contact solar cell provided according to an embodiment of the present invention;

[0020] Figure 7 This is a partial back-side structure of the fifth structure of a back-contact solar cell provided according to an embodiment of the present invention;

[0021] Figure 8 This is a partial cross-sectional structural diagram of the insulation structure within the welding area provided according to an embodiment of the present utility model;

[0022] Figure 9 This is a partial cross-sectional structural diagram of the insulation structure in other areas according to an embodiment of the present utility model;

[0023] Figure 10 This is a partial cross-sectional structural diagram of the light conversion insulation component in other areas according to an embodiment of the present utility model.

[0024] The attached figures are labeled as follows:

[0025] 10-Battery structure; 11-Battery body; 12-Positive electrode fine grid line; 121-Positive electrode fine grid segment; 13-Negative electrode fine grid line; 131-Negative electrode fine grid segment; 14-Negative electrode main grid line; 15-Positive electrode main grid line; 16-Welding point; 17-Solder pad; 20'-Insulating adhesive; 20-Insulating structure; 21-Light conversion insulating component; 22-High reflectivity insulating component; 23-Inclined slope; 51-Negative electrode solder strip; 52-Positive electrode solder strip; K1-Upper base of trapezoidal structure; K2-Lower base of trapezoidal structure; K3-Vertical surface. Detailed Implementation

[0026] For back-contact solar cells, they can be formed into a cell string by electrically connecting fine grid lines to solder ribbons, or by electrically connecting fine grid lines to main grid lines and then connecting the main grid lines to solder ribbons to form a cell string. Furthermore, on a back-contact solar cell, the fine grid line can be a single, continuous grid line in the P-region or N-region, or it can be multiple discontinuous fine grid line segments.

[0027] For example, such as Figure 1 As shown, in existing back-contact solar cells, alternating positive electrode fine grid lines 12 and negative electrode fine grid lines 13 are arranged on the back side of the cell structure 10. These positive electrode fine grid lines 12 and negative electrode fine grid lines 13 form a continuous grid line. For this existing cell structure 10, it is generally as follows... Figure 1 The structure shown incorporates insulating adhesive 20' to achieve insulation. Solder points 16 are located on each fine grid line. Additionally, the... Figure 1 This is merely an illustrative example showing a structure without main grid lines; those skilled in the art will understand that, in... Figure 1Based on the structure shown, main grid lines can be added. Regarding this... Figure 1 In the structure shown, during the laser welding process between the welding strip and the fine grid line (positive fine grid line 12 or negative fine grid line 13), the laser spot deflection causes the laser spot to hit the insulating adhesive 20', resulting in uneven color changes in the insulating adhesive 20'.

[0028] In addition, such as Figure 2 As shown, in existing back-contact solar cells, alternating positive electrode fine grid lines 12 and negative electrode fine grid lines 13 are arranged on the back side of the cell structure 10. Each positive electrode fine grid line 12 includes multiple spaced positive electrode fine grid segments 121, and each negative electrode fine grid line 13 includes multiple spaced negative electrode fine grid segments 131. A positive electrode main grid line 15 (or solder ribbon) passes through the gaps between adjacent negative electrode fine grid segments 131 and is electrically connected to the positive electrode fine grid segment 121. A negative electrode main grid line 14 (or solder ribbon) passes through the gaps between adjacent positive electrode fine grid segments 121 and is electrically connected to the negative electrode fine grid segment 131. Regarding this… Figure 2 The structure shown typically has insulating adhesive 20' at the ends of the positive electrode fine gate segment 121 and the negative electrode fine gate segment 131. For this structure, multiple pads 17 are typically set along a main gate line (positive main gate line 15 or negative main gate line 14). These pads 17 are the positions where the solder strip is soldered to the positive main gate line 15 or the negative main gate line 14. The insulating adhesive 20' near the pads 17 is easily affected by the laser, which can also cause uneven color changes in the insulating adhesive 20'.

[0029] To address the aforementioned problems of existing back-contact solar cells, this invention provides a novel back-contact solar cell and photovoltaic module.

[0030] The specific structure of the back-contact solar cell and photovoltaic module provided in the embodiments of this utility model will be described in detail below.

[0031] in, Figures 3 to 7 This is a partial back structure diagram of a back-contact solar cell provided according to an embodiment of the present invention; Figure 8 and Figure 9 This is a partial cross-sectional structural diagram of the insulation structure 20 provided according to an embodiment of the present utility model; Figure 10 This is a cross-sectional structural schematic diagram of the light conversion insulating component 21 provided according to an embodiment of the present utility model.

[0032] Specifically, such as Figures 3 to 7 As shown, the back-contact solar cell provided in this embodiment of the present invention may include: a cell structure 10 and a plurality of insulating structures 20.

[0033] Specifically, such as Figures 3 to 7As shown, the battery structure 10 may include: a battery body 11, with alternating positive electrode fine grid lines 12 and negative electrode fine grid lines 13 on the back side of the battery body 11; and a plurality of insulating structures 20 spaced apart on the positive electrode fine grid lines 12 and negative electrode fine grid lines 13.

[0034] More specifically, such as Figures 3 to 7 As shown, the insulation structure 20 may include: a light conversion insulation component 21 and a high-reflectivity insulation component 22, with the high-reflectivity insulation component 22 fixed to the side of the light conversion insulation component 21.

[0035] The light conversion insulator 21 can convert light that cannot be absorbed by the back-contact solar cell (such as ultraviolet light) into light that can be absorbed by the back-contact solar cell.

[0036] The highly reflective insulating element 22 can reflect the laser light irradiated onto it to prevent the laser light from reaching the light conversion insulating element 21, thereby preventing the laser energy from causing the light conversion insulating element 21 to change color.

[0037] More specifically, such as Figure 3 and Figure 4 As shown, each insulating structure 20 includes a light conversion insulating element 21 that is fixed and covers all insulating positions of the positive electrode fine grid line 12 and all insulating positions of the negative electrode fine grid line 13, so as to prevent the positive electrode fine grid line 12 from making electrical contact with the negative electrode solder strip 51 and to prevent the negative electrode fine grid line 13 from making electrical contact with the positive electrode solder strip 52.

[0038] That is, Figure 3 and Figure 4 The structure shown has the insulation structure 20 installed at each insulation position to facilitate the fabrication process of the back contact solar cell.

[0039] In addition, such as Figure 5 and Figure 7 As shown, each insulating structure 20 includes a light-conversion insulating element 21 that is fixed and covers a portion of the insulating position of the positive electrode fine grid line 12 and a portion of the insulating position of the negative electrode fine grid line 13. For the insulating positions where no insulating structure 20 is provided, conventional insulating adhesive can be used, or only the light-conversion insulating element 21 can be provided.

[0040] Figure 5 and Figure 7 The structure shown also prevents electrical contact between the positive electrode fine grid line 12 and the negative electrode solder strip 51, and prevents electrical contact between the negative electrode fine grid line 13 and the positive electrode solder strip 52. Through Figure 5 and Figure 7 The structure shown, with its differentiated insulation structure at different insulation locations, can reduce the number of high-reflectivity insulation components 22, thereby lowering the cost of the back-contact solar cell.

[0041] The aforementioned negative electrode solder strip 51 is generally electrically connected to the negative electrode fine grid line 13, and the positive electrode solder strip 52 is generally electrically connected to the positive electrode fine grid line 12. Through the negative electrode solder strip 51 and the positive electrode solder strip 52, series connection between back-contact solar cells or series connection between cells cut from back-contact solar cells can be achieved. The negative electrode solder strip 51 is electrically connected to the negative electrode fine grid line 13. This connection can be direct or indirect (e.g., the negative electrode main grid line 14 is electrically connected to the negative electrode fine grid line 13, and the negative electrode solder strip 51 is electrically connected to the negative electrode main grid line 14). The positive electrode solder strip 52 is electrically connected to the positive electrode fine grid line 12. This connection can be direct or indirect (e.g., the positive electrode main grid line 15 is electrically connected to the positive electrode fine grid line 12, and the positive electrode solder strip 52 is electrically connected to the positive electrode main grid line 15).

[0042] The light conversion insulator 21 is generally a structure that converts light in the 300-380nm wavelength band into light in the 550-800nm ​​wavelength band. The light conversion insulator 21 can be formed by structural design to convert light in the 300-380nm wavelength band into light in the 550-800nm ​​wavelength band, or it can be formed by curing materials (such as materials containing acrylate oligomers, active monomers, photopolymerization initiators and downconversion agents).

[0043] In addition, the high-reflectivity insulating component 22 is generally a structure that reflects light in the 800~1500nm wavelength band. The high-reflectivity insulating component 22 can achieve the reflection of light in the 800~1500nm wavelength band through structural design, or it can be formed by curing materials (such as materials containing acrylate oligomers, active monomers, photopolymerization initiators, and reflective agents).

[0044] For the back-contact solar cells with the above-described structures, since the insulating structure 20 includes a light-conversion insulating element 21 and a high-reflectivity insulating element 22, and the high-reflectivity insulating element 22 is fixed to the side of the light-conversion insulating element 21, when the light-conversion insulating element 21 is fixed and covers part or all of the insulating positions of the positive electrode fine grid line 12 and part or all of the insulating positions of the negative electrode fine grid line 13, electrical contact between the positive electrode fine grid line 12 and the negative electrode solder strip 51 can be avoided, and electrical contact between the negative electrode fine grid line 13 and the positive electrode solder strip 52 can be avoided. During the laser welding process of the solder ribbon 51 and the negative electrode solder ribbon 52 to the battery body 11, since the high reflectivity insulating component 22 is fixed to the side of the light conversion insulating component 21, the high reflectivity insulating component 22 is closer to the laser spot, which can prevent the laser spot from affecting the light conversion insulating component 21. In addition, even if the laser spot shifts during the laser welding process, the high reflectivity insulating component 22 can reflect the laser, which can prevent the laser from affecting the light conversion insulating component 21 and prevent the insulation structure 20 from discoloring, so as to ensure the appearance consistency of the photovoltaic module formed based on the back contact solar cell.

[0045] Furthermore, the light conversion insulator 21 included in the insulation structure 20 can reduce light reflection and increase the light reaching the battery body 11, thereby improving the light utilization rate of the back-contact solar cell. Further, the light conversion insulator 21 can convert wavelengths of light that cannot be utilized by the battery body 11 into wavelengths that can be utilized by the battery body 11, thereby further increasing the light reaching the battery body 11 and further improving the light utilization rate of the back-contact solar cell.

[0046] Furthermore, there can be various structures for the positive electrode fine grid lines 12 and the negative electrode fine grid lines 13 on the battery body 10.

[0047] like Figure 3 As shown, for the first structure of the positive electrode fine grid line 12 and the negative electrode fine grid line 13: each positive electrode fine grid line 12 and each negative electrode fine grid line 13 are a through straight structure; the high-reflectivity insulating element 22 of each insulating structure 20 disposed on the positive electrode fine grid line 12 is fixed to the side of the light conversion insulating element 21 of the same insulating structure 20 near the negative electrode fine grid line 13; the high-reflectivity insulating element 22 of each insulating structure 20 disposed on the negative electrode fine grid line 13 is fixed to the side of the light conversion insulating element 21 of the same insulating structure 20 near the positive electrode fine grid line 12.

[0048] like Figures 4 to 7As shown, for the second structure of the positive electrode fine grid line 12 and the negative electrode fine grid line 13: each positive electrode fine grid line 12 may include: multiple positive electrode fine grid segments 121 spaced apart; a first interval region between each two adjacent positive electrode fine grid segments 121 corresponds to a negative electrode solder strip 51; each positive electrode fine grid segment 121 has an insulating structure 20 at both ends, and the light conversion insulating element 21 of each insulating structure 20 covers part or all of the ends of the positive electrode fine grid segment 121; the high reflectivity insulating element 22 of each insulating structure 20 is fixed to the side of the light conversion insulating element 21 of the same insulating structure 20 near the negative electrode solder strip 51. Each negative electrode fine grid line 13 may include: multiple negative electrode fine grid segments 131 spaced apart; a second interval region between each two adjacent negative electrode fine grid segments 131 corresponds to a positive electrode solder strip 52; each negative electrode fine grid segment 131 has an insulating structure 20 at both ends, and the light conversion insulating element 21 of each insulating structure 20 covers part or all of the ends of the negative electrode fine grid segment 131, and the high reflectivity insulating element 22 of each insulating structure 20 is fixed to part or all of the light conversion insulating element 21 of the same insulating structure 20 on the side near the positive electrode solder strip 52.

[0049] It is worth noting that, Figure 3 The first combined structure of the present invention, which provides a positive fine grid line 12 and a negative fine grid line 13, is shown only by way of example. Figures 4 to 7 The second combined structure of the positive electrode fine grid line 12 and the negative electrode fine grid line 13 provided by this invention is only shown as an example. Alternatively, the battery body 10 of this invention can also be a structure formed by combining the positive electrode fine grid line 12 in the first structure and the negative electrode fine grid line 13 in the second structure, or a structure formed by combining the positive electrode fine grid line 12 in the second structure and the negative electrode fine grid line 13 in the first structure, wherein... Figures 3 to 7 Based on the structure shown, those skilled in the art can understand the combination of the positive fine gate line 12 in the first structure and the negative fine gate line 13 in the second structure, as well as the combination of the positive fine gate line 12 in the second structure and the negative fine gate line 13 in the first structure, which will not be described in detail here.

[0050] like Figure 3 and Figure 4 As shown, an insulation structure 20 is provided at each insulation location.

[0051] Alternatively, the insulation structure 20 can be provided only in the welding area on the back of the battery body 11. Specifically, there are two possible structures for providing the insulation structure 20 in the welding area.

[0052] Specifically, the first type of insulation structure 20 is provided in the welding area: such as Figure 5As shown, each positive electrode fine grid line 12 includes: multiple positive electrode fine grid segments 121 spaced apart; a first interval region between each two adjacent positive electrode fine grid segments 121 corresponds to a negative electrode solder strip 51; the first interval region also has multiple welding areas spaced apart along the extension direction of the negative electrode solder strip 51; each negative electrode fine grid line 13 includes: multiple negative electrode fine grid segments 131 spaced apart; a second interval region between each two adjacent negative electrode fine grid segments 131 corresponds to a positive electrode solder strip 52; the second interval region also has multiple welding areas spaced apart along the extension direction of the positive electrode solder strip 52, the welding areas being centered on the welding position of the negative electrode solder strip 51 or the positive electrode solder strip 52; that is, the back side of the battery body 11 may include welding areas and other areas besides the welding areas, wherein the welding areas are centered on the welding position of the negative electrode solder strip 51 or the positive electrode solder strip 52. Specifically, the welding area is generally determined by the possible offset of the laser spot. More specifically, as Figure 5 and Figure 7 As shown, insulating structures 20 are provided at the ends of the positive electrode fine grid segment 121 and the negative electrode fine grid segment 131 located in the welding area. The high-reflectivity insulating element 22 of the insulating structure 20 is located on the side closer to the negative electrode solder strip 51 or the positive electrode solder strip 52, while the light-conversion insulating element 21 of the insulating structure 20 is located on the side away from the negative electrode solder strip 51 or the positive electrode solder strip 52. Only the light-conversion insulating element 21 or other types of insulating elements are provided at the ends of the negative electrode fine grid segment 131 and the positive electrode fine grid segment 121 outside the welding area. This reduces the cost of the back-contact solar cell. It is worth noting that these other types of insulating elements can be existing conventional insulating elements or insulating elements with other functions (such as displaying a specific color). These insulating elements can be formed by curing various functional insulating adhesives.

[0053] Furthermore, regardless of Figure 4 Insulation structure 20 is provided at each of the insulation locations shown. Figure 5 and Figure 7 The insulation structure 20 shown is only provided within the welding area. For the insulation structure 20 located within the welding area, such as... Figure 8As shown, the side of the insulating structure 20 near the negative electrode solder strip 51 or the positive electrode solder strip 52 includes an inclined slope 23; the inclined slope 23 of the two insulating structures 20 located on both sides of the first interval area or the second interval area and opposite to each other in the welding area encloses a welding space with a trapezoidal cross section, and the welding space is used to limit the negative electrode solder strip 51 or the positive electrode solder strip 52. By using the inclined slopes 23 of two insulating structures 20 located on both sides of the first or second interval area within the welding area to enclose a welding space with a trapezoidal cross-section, the negative electrode solder strip 51 or the positive electrode solder strip 52 can reach directly above the welding position (such as the solder pad 17) along the inclined slopes 23 of the welding space, and limit the negative electrode solder strip 51 or the positive electrode solder strip 52 in the welding space, thereby guiding and positioning the negative electrode solder strip 51 or the positive electrode solder strip 52 to avoid displacement of the negative electrode solder strip 51 or the positive electrode solder strip 52 during the welding process, so that the negative electrode solder strip 51 or the positive electrode solder strip 52 can form a stable electrical connection at the welding position.

[0054] It is worth noting that, Figure 8 As shown by way of example only, the inclined slope 23 is formed on the basis of forming an inclined slope on the side of the light conversion insulator 21.

[0055] Alternatively, the inclined slope 23 can be obtained by setting the side of the light conversion insulating member 21 as a vertical surface and then setting a high-reflectivity insulating member 22 with an inclined structure on the vertical surface.

[0056] For example Figure 4 As shown, in cases where insulation structures 20 are also provided in other areas (i.e., areas outside the welding area), for insulation structures 20 located in other areas, such as... Figure 9 As shown, the side of the insulating structure 20 near the negative electrode solder strip 51 or the positive electrode solder strip 52 can be a vertical surface K3 (the vertical surface K3 is the side of the high-reflectivity insulating component 22), and the vertical surface K3 is consistent with the thickness direction of the battery body 11; the vertical surfaces K3 of the two insulating structures 20 located on both sides of the interval area and opposite each other in other areas enclose a space with a rectangular cross section.

[0057] against Figure 5 As shown, the structure in which only the light conversion insulation element 21 is installed in other areas is as follows: Figure 10 As shown, the side of the light conversion insulating component 21 near the negative electrode solder strip 51 or the positive electrode solder strip 52 can be a vertical surface K3, and the vertical surface K3 is consistent with the thickness direction of the battery body 11.

[0058] Regardless Figure 9 The structure shown is still Figure 10 The structure shown is located in other areas, on two opposing vertical planes K3 located on either side of the first or second interval region. Figure 9The vertical planes K3 of the two opposing insulating structures 20 are shown. Figure 10 The distance between the vertical surfaces K3 of the two opposing optical conversion insulators 21 shown (as indicated) Figure 9 The t4 or shown Figure 10 The width t5 shown is greater than the width t2 of the negative electrode solder strip 51 or the positive electrode solder strip 52.

[0059] Additionally, a second structure is provided in the welding area with insulation structure 20: such as Figure 6 As shown, each positive electrode fine grid line 12 includes: a plurality of positive electrode fine grid segments 121 spaced apart; a first interval region between each two adjacent positive electrode fine grid segments 121 corresponds to a negative electrode solder strip 51; the first interval region is also provided with a plurality of welding regions spaced apart along the extension direction of the negative electrode solder strip 51; each negative electrode fine grid line 13 includes: a plurality of negative electrode fine grid segments 131 spaced apart; a second interval region between each two adjacent negative electrode fine grid segments 131 corresponds to a positive electrode solder strip 52; the second interval region is also provided with a plurality of welding regions spaced apart along the extension direction of the positive electrode solder strip 52. The welding area is defined centered on the welding position of the negative electrode solder strip 51 or the positive electrode solder strip 52. A welding through-hole is provided at the center of the insulating structure 20, and a high-reflectivity insulating component 22 surrounds the welding through-hole. A light-conversion insulating component 21 is located on the side of the high-reflectivity insulating component 22 away from the welding through-hole. The insulating structure 20 is located within the welding area, and the orthogonal projection of the welding area falls within the area of ​​the insulating structure 20. The ends of the positive electrode fine grid segment 121 and the negative electrode fine grid segment 131, which are not covered by the insulating structure 20, are only provided with light-conversion insulating components 21 or other types of insulating components. This structure can also reduce the cost of back-contact solar cells.

[0060] Furthermore, for the second structure in which an insulating structure 20 is provided in the welding area, the inner surface of the welding through hole includes an inclined surface, which encloses a welding space with a trapezoidal cross-section. This welding space is used to limit the negative electrode solder strip 51 or the positive electrode solder strip 52. By enclosing the trapezoidal cross-section of the welding space through the inner surface of the welding through hole, the negative electrode solder strip 51 or the positive electrode solder strip 52 can reach directly above the welding position along the inclined surface of the welding space, and the negative electrode solder strip 51 or the positive electrode solder strip 52 is limited in the welding space. This guides and positions the negative electrode solder strip 51 or the positive electrode solder strip 52, preventing it from shifting during the welding process, and ensuring that the negative electrode solder strip 51 or the positive electrode solder strip 52 can form a stable electrical connection at the welding position.

[0061] Specifically, for structures with insulation structure 20 installed in the welding area, it is possible to... Figure 4 , Figure 5 and Figure 7 As shown, the insulation structure 20 located within the welding area can be an independent, separate structure. Alternatively, it can be as follows: Figure 6As shown, within the welding area, the integral insulation structure 20 covers the ends of multiple negative electrode fine grid segments 131 or the ends of multiple positive electrode fine grid segments 121.

[0062] Furthermore, such as Figures 4 to 7 As shown, the battery structure 10 may further include: a negative main grid line 14 disposed in the first interval region and electrically connected to the negative fine grid line 13, and a positive main grid line 15 disposed in the second interval region and electrically connected to the positive fine grid line 12.

[0063] More specifically, based on the aforementioned insulating structure 20 including the inclined surface, such as Figure 8 As shown, the upper base K1 of the trapezoidal structure formed by the two opposite inclined slopes 23 corresponding to the negative main grid line 14 is lower than the lower surface of the negative main grid line 14; similarly, the upper base of the trapezoidal structure formed by the two opposite inclined slopes 23 corresponding to the positive main grid line 15 is lower than the lower surface of the positive main grid line 15. By limiting the upper base K1 of the trapezoidal structure formed by the two opposite inclined slopes 23 corresponding to the negative main grid line 14 to be lower than the lower surfaces of both the negative main grid line 14 and the positive main grid line 15, a stable and reliable electrical connection can be ensured between the solder ribbon and the main grid lines (negative solder ribbon 51 and negative main grid line 14, positive solder ribbon 52 and positive main grid line 15). For this structure, laser welding is used to weld the solder strip to the main grid line (the negative main grid line 14 is welded to the negative solder strip 51, and the positive main grid line 15 is welded to the positive solder strip 52). During the laser welding process, the laser spot irradiates the solder strip, and the part of the laser spot outside the solder strip will irradiate the inclined surface 23. The high-reflectivity insulating component 22 will reflect the laser spot, thereby effectively protecting the light conversion insulating component 21 and avoiding damage to the light conversion insulating component 21 from laser irradiation.

[0064] It is worth noting that the lower surface of the negative main grid line 14 or the lower surface of the positive main grid line 15 refers to the surface of the negative main grid line 14 or the positive main grid line 15 located below during the use of the back contact solar cell.

[0065] In addition, such as Figure 8 As shown, the width t3 of the upper base K1 of the trapezoidal structure is less than the width t2 of the negative electrode solder strip 51 or the positive electrode solder strip 52, and the width t1 of the lower base K2 of the trapezoidal structure is greater than the width t2 of the negative electrode solder strip 51 or the positive electrode solder strip 52, and the width t1 of the lower base K2 of the trapezoidal structure is greater than the diameter of the laser spot. By matching these dimensions, it can be ensured that the entire laser spot falls within the area enclosed by the high-reflectivity insulating component 22, enabling the high-reflectivity insulating component 22 to reflect the laser. On the one hand, this avoids the laser affecting the light conversion insulating component 21; on the other hand, the high-reflectivity insulating component 22 reflects the laser, allowing the reflected laser to be reused, reducing welding energy consumption, and ensuring more stable welding.

[0066] Furthermore, the length of the light conversion insulator 21 in the extension direction of the negative electrode fine grid line 13 (or the negative electrode fine grid segment 131 included in the negative electrode fine grid line 13) or the extension direction of the positive electrode fine grid line 12 (or the positive electrode fine grid segment 121 included in the positive electrode fine grid line 12) is generally 30mm to 35mm. For example, the length of the light conversion insulator 21 can be 30mm, 32mm, 33mm or 35mm, etc. By controlling the length of the light conversion insulator 21, the insulation of the end of the negative electrode fine grid segment 131 or the end of the positive electrode fine grid segment 121 can be effectively guaranteed.

[0067] Furthermore, the length of the high-reflectivity insulating element 22 in the extension direction of the negative electrode fine gate segment 131 or the extension direction of the positive electrode fine gate segment 121 is 5mm to 10mm. For example, the length of the high-reflectivity insulating element 22 can be 5mm, 6mm, 7mm, 9mm or 10mm, etc. By controlling the length of the high-reflectivity insulating element 22, the performance of the high-reflectivity insulating element 22 in reflecting laser light can be effectively guaranteed, and the influence of laser light on the light conversion insulating element 21 can be avoided.

[0068] Furthermore, this embodiment of the invention also provides a battery string structure. The battery string structure includes: a back-contact solar cell provided in any of the above embodiments, or battery cells cut from a back-contact solar cell provided in any of the above embodiments.

[0069] In addition, the battery string structure may include, in addition to the back-contact solar cell provided in any of the above embodiments or the battery cells cut from the back-contact solar cell provided in any of the above embodiments, negative electrode solder strip 51 and positive electrode solder strip 52 for connecting the back-contact solar cell or battery cells in series.

[0070] Furthermore, this embodiment of the invention also provides a photovoltaic module. The photovoltaic module may include the back-contact solar cell provided in any of the above embodiments, or solar cells cut from the back-contact solar cell provided in any of the above embodiments.

[0071] In addition to the back-contact solar cells or cells cut from the back-contact solar cells provided in any of the above embodiments, photovoltaic modules may also include negative electrode solder ribbons 51 and positive electrode solder ribbons 52 for connecting the back-contact solar cells or cells in series, encapsulating film, cover plate, and back sheet. The relationship between the back-contact solar cells or cells and the negative electrode solder ribbons 51 and positive electrode solder ribbons 52, encapsulating film, cover plate, and back sheet is basically the same as that of existing photovoltaic modules and will not be elaborated further here.

[0072] The above steps are provided only to help understand the method, structure, and core idea of ​​this utility model. For those skilled in the art, various improvements and modifications can be made to this utility model without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this utility model.

Claims

1. A back contact solar cell, characterized by, include: The battery structure (10) and multiple insulating structures (20), wherein, The battery structure (10) includes: a battery body (11), and alternating positive electrode fine grid lines (12) and negative electrode fine grid lines (13) on the back side of the battery body (11). Multiple insulating structures (20) are spaced apart on the positive electrode fine grid line (12) and the negative electrode fine grid line (13). The insulation structure (20) includes: a light conversion insulation component (21) and a high reflectivity insulation component (22), wherein the high reflectivity insulation component (22) is fixed to the side of the light conversion insulation component (21); Each of the insulating structures (20) includes an optical conversion insulating element (21) which is fixed and covers part or all of the insulating position of the positive electrode fine grid line (12) and part or all of the insulating position of the negative electrode fine grid line (13).

2. The back-contact solar cell according to claim 1, characterized in that, Each of the positive electrode fine grid lines (12) and each of the negative electrode fine grid lines (13) are through straight lines; The highly reflective insulating element (22) of each of the insulating structures (20) disposed on the positive electrode fine grid line (12) is fixed to the side of the light conversion insulating element (21) of the same insulating structure (20) near the negative electrode fine grid line (13); The high-reflectivity insulator (22) of each of the insulating structures (20) disposed on the negative electrode fine grid line (13) is fixed to the side of the light conversion insulator (21) of the same insulating structure (20) near the positive electrode fine grid line (12).

3. The back-contact solar cell according to claim 1, characterized in that, Each of the positive electrode fine grid lines (12) includes: a plurality of positive electrode fine grid segments (121) spaced apart; a first interval region between each two adjacent positive electrode fine grid segments (121) corresponds to a negative electrode solder strip (51); each of the two ends of each positive electrode fine grid segment (121) is provided with an insulating structure (20), the light conversion insulating element (21) of each insulating structure (20) covers part or all of the ends of the positive electrode fine grid segments (121), and the high reflectivity insulating element (22) of each insulating structure (20) is fixed to the side of the light conversion insulating element (21) of the same insulating structure (20) near the negative electrode solder strip (51); Each of the negative electrode fine grid lines (13) includes: a plurality of negative electrode fine grid segments (131) spaced apart; a second interval region between each two adjacent negative electrode fine grid segments (131) corresponds to a positive electrode solder strip (52); each of the two ends of each negative electrode fine grid segment (131) is provided with an insulating structure (20), the light conversion insulating element (21) of each insulating structure (20) covers part or all of the ends of the negative electrode fine grid segments (131), and the high reflectivity insulating element (22) of each insulating structure (20) is fixed to the side of the light conversion insulating element (21) of the same insulating structure (20) near the positive electrode solder strip (52).

4. The back-contact solar cell according to claim 1, characterized in that, Each of the positive electrode fine grid lines (12) includes: a plurality of positive electrode fine grid segments (121) spaced apart; a first interval region between each two adjacent positive electrode fine grid segments (121) corresponds to a negative electrode solder strip (51); the first interval region is further provided with a plurality of welding areas spaced apart along the extension direction of the negative electrode solder strip (51); Each of the negative electrode fine grid lines (13) includes: a plurality of negative electrode fine grid segments (131) spaced apart; a second interval region between each two adjacent negative electrode fine grid segments (131) corresponds to a positive electrode solder strip (52); the second interval region is also provided with a plurality of welding areas spaced apart along the extension direction of the positive electrode solder strip (52); The welding area is defined with the welding position of the negative electrode welding strip (51) or the positive electrode welding strip (52) as the center; The insulating structure (20) is provided at the end of the positive electrode fine grid segment (121) and the end of the negative electrode fine grid segment (131) located in the welding area. The high reflectivity insulating element (22) of the insulating structure (20) is located on the side close to the negative electrode solder strip (51) or the positive electrode solder strip (52), and the light conversion insulating element (21) of the insulating structure (20) is located on the side away from the negative electrode solder strip (51) or the positive electrode solder strip (52). The ends of the negative electrode fine grid segment (131) and the positive electrode fine grid segment (121) that do not fall into the welding area are provided with only the light conversion insulating element (21) or other types of insulating elements.

5. The back-contact solar cell according to claim 4, characterized in that, For the insulating structure (20) located in the welding area, its side near the negative electrode solder strip (51) or the positive electrode solder strip (52) includes an inclined slope (23). The inclined slopes (23) of the two insulating structures (20) located on both sides of the first interval area or the second interval area and opposite to each other in the welding area enclose a welding space with a trapezoidal cross section. The welding space is used to limit the negative electrode welding strip (51) or the positive electrode welding strip (52).

6. The back-contact solar cell according to claim 1, characterized in that, Each of the positive electrode fine grid lines (12) includes: a plurality of positive electrode fine grid segments (121) spaced apart; a first interval region between each two adjacent positive electrode fine grid segments (121) corresponds to a negative electrode solder strip (51); the first interval region is further provided with a plurality of welding areas spaced apart along the extension direction of the negative electrode solder strip (51); Each of the negative electrode fine grid lines (13) includes: a plurality of negative electrode fine grid segments (131) spaced apart; a second interval region between each two adjacent negative electrode fine grid segments (131) corresponds to a positive electrode solder strip (52); the second interval region is also provided with a plurality of welding areas spaced apart along the extension direction of the positive electrode solder strip (52); The welding area is defined with the welding position of the negative electrode welding strip (51) or the positive electrode welding strip (52) as the center; The insulation structure (20) has a welding through hole at its center, the high reflectivity insulation component (22) is arranged around the welding through hole, and the light conversion insulation component (21) is arranged on the side of the high reflectivity insulation component (22) away from the welding through hole; The insulating structure (20) is disposed in the welding area, and the orthographic projection of the welding area falls within the area of ​​the insulating structure (20); The ends of the positive electrode fine grid segment (121) not covered by the insulating structure (20) and the ends of the negative electrode fine grid segment (131) are provided with only the light conversion insulating element (21) or other types of insulating elements.

7. The back contact solar cell of claim 6, wherein, The inner surface of the welding through hole includes an inclined surface, which encloses a welding space with a trapezoidal cross-section. The welding space is used to limit the negative electrode welding strip (51) or the positive electrode welding strip (52).

8. The back-contact solar cell according to any one of claims 3-7, characterized in that, The battery structure (10) further includes: a negative main grid line (14) disposed in the first interval region and electrically connected to the negative fine grid line (13), and a positive main grid line (15) disposed in the second interval region and electrically connected to the positive fine grid line (12).

9. The back-contact solar cell according to any one of claims 1-7, characterized in that, The length of the light conversion insulating component (21) in the extension direction of the negative electrode fine grid line (13) or the extension direction of the positive electrode fine grid line (12) is 30mm~35mm; And / or, The length of the high-reflectivity insulating component (22) in the extension direction of the negative electrode fine grid line (13) or the extension direction of the positive electrode fine grid line (12) is 5mm to 10mm; And / or, The light conversion insulating component (21) is a structure that converts light in the 300~380nm band into light in the 550~800nm ​​band; And / or, The high-reflectivity insulating component (22) is a structure that reflects light in the 800~1500nm wavelength band.

10. A photovoltaic module, characterized by, include: The back-contact solar cell according to any one of claims 1 to 9, or the cell sliced ​​from the back-contact solar cell according to any one of claims 1 to 9.

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