Solar cell module, preparation method thereof and solar cell

Abstract

The invention relates to a solar cell module and a preparation method thereof, and a solar cell, the solar cell module comprises a plurality of cells, and each cell comprises a substrate and an auxiliary grid located on the substrate; a main grid is arranged on the auxiliary grid, and the main grid comprises a conductive piece and a conductive layer wrapping at least part of the surface of the conductive piece; each conductive piece comprises a main body section located on the corresponding battery piece and a connecting section with at least one end exceeding the corresponding battery piece, and the multiple battery pieces are connected in series through the connecting sections. According to the invention, the conductive part is laid on the battery piece and the conductive layer is coated on the surface of the conductive part, and the conductive part and the conductive layer jointly bear the effect of collecting the auxiliary grid current, so that the shading loss caused by the welding strip is reduced, and the performance loss caused by the pollution of the soldering flux to the battery piece is reduced; equipment investment and process cost of a traditional welding end are saved, and a low-temperature metal interconnection process is realized.

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaic cells, and in particular relates to a solar cell assembly and a preparation method thereof, and a solar cell. Background Art

[0002] The metallization process plays a crucial role in the production of photovoltaic cells. During the metallization process, the electrode paste is bonded to the front and back of the cell through sintering and curing to form electrodes. The electrodes include a main grid and a fine grid. The fine grid collects the current generated by the cell and transmits it to the main grid, which connects to the cell's external leads and outputs the current. In the traditional photovoltaic module manufacturing process, the conductive main grid and fine grid are generally first screen-printed on the cell, and then the cells are connected in series through precision welding to form a preliminary current transmission path.

[0003] However, the high temperatures of the string soldering process can damage the cells, and the soldering flux used can also contaminate the cells, leading to performance losses for the photovoltaic cells. Furthermore, the use of solder ribbon to solder the busbar during string soldering increases its height, resulting in some light shading. Furthermore, issues such as broken busbars during the screen printing process can also lead to a certain loss in cell efficiency. Summary of the Invention

[0004] The purpose of the present invention is to reduce the shading loss and performance loss of photovoltaic cells, and further achieve cost reduction and efficiency improvement.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides a solar cell assembly, comprising a plurality of cell sheets, wherein the cell sheets include a substrate and a secondary grid located on the substrate; a main grid is arranged on the secondary grid, and the main grid includes a conductive member and a conductive layer coated on at least a portion of the surface of the conductive member; the conductive member includes a main section located on the cell sheet and a connecting section with at least one end extending beyond the cell sheet, and a plurality of the cell sheets are connected in series through the connecting section.

[0006] Optionally, the distance A between two adjacent conductive members is 0-230 mm, preferably 0-12 mm.

[0007] Optionally, the conductive member includes a conductive tape and / or a conductive wire; the diameter of the conductive wire is 0-3 mm, preferably 0-0.06 mm; and / or the width of the conductive tape is 0.05-3 mm and the thickness is 0.01-0.05 mm.

[0008] Optionally, the conductivity of the conductive member is 0.5×10 7 -7.0×10 7S / m; the material of the conductive member is selected from one or more of silver, copper, aluminum, nickel, iron and plated copper.

[0009] Optionally, the lengths of the connecting segments on multiple battery cells are equal; the length of the connecting segments is 0-0.4 mm.

[0010] Optionally, the conductive layer completely covers the surface of the main segment, and the cross-sectional shape of the main grid is selected from one or more of a trapezoid, a square, a circle and a triangle; or, the conductive layer is filled between the conductive part and the substrate; preferably, the cross-sectional shape of the main grid is a triangle, the bottom width of the main grid is 0-60 μm, preferably 0-35 μm, and the height is 0-24 μm, preferably 0-20 μm.

[0011] Optionally, the width of the auxiliary grid is 3-30 μm and the thickness is 1-20 μm; optionally, the auxiliary grid includes an auxiliary grid conductive member and a gate material layer covering the auxiliary grid conductive member; the auxiliary grid conductive member is a conductive wire, and the diameter of the auxiliary grid conductive member is 0-1 mm.

[0012] Optionally, the cell is selected from one or a composite cell of two of aluminum back surface field cells, PERC cells, TOPCon cells, heterojunction cells, BC cells, perovskite solar cells and tandem solar cells.

[0013] A second aspect of the present invention provides a method for preparing a solar cell module, the method comprising the following steps: forming a secondary grid on the surface of the photovoltaic cell to obtain a first cell; Laying a plurality of conductive members on the surface of the first cell so that the conductive members cross-contact the auxiliary grid to obtain a second cell; wherein at least one end of the conductive member extends to the outside of the first cell to form a connecting section; Printing a busbar paste on at least a portion of the surface of the conductive member to form a busbar to obtain a third cell; The third battery cells are connected in series via the connecting sections.

[0014] Optionally, when laying the conductive members, the distance between two adjacent conductive members is 0-230 mm; the conductive members include conductive tapes and / or conductive wires; the diameter of the conductive wires is 0-3 mm; and / or the width of the conductive tape is 0.05-3 mm and the thickness is 0.01-0.05 mm; optionally, the length of the connecting section is 0-0.4 mm.

[0015] Optionally, the method of printing the busbar on the surface of the conductive member includes the following steps: making the pattern on the screen correspond to the conductive member on the second battery cell; placing the busbar slurry on the upper surface of the screen, applying pressure to the busbar slurry so that the busbar slurry is printed on the surface of the second battery cell to obtain a battery cell with printed busbar lines; and drying the battery cell with printed busbar lines to obtain the third battery cell.

[0016] Optionally, the busbar slurry comprises 80-100wt% of metal powder and 0-20wt% of an additive; the metal powder is selected from one or more of silver powder, copper powder, aluminum powder and nickel powder; the additive is selected from one or more of a thixotropic agent, a binder, a curing agent, a dispersant, a resin and a solvent; the viscosity of the busbar slurry at 10 rpm is 30-600 Pa·s / 25°C.

[0017] Optionally, the bottom width of the main grid is 0-60 μm, and the height is 0-24 μm; the width of the auxiliary grid is 3-30 μm, and the thickness is 1-20 μm.

[0018] Optionally, the cell is selected from one or a composite cell of two of aluminum back surface field cells, PERC cells, TOPCon cells, heterojunction cells, BC cells, perovskite solar cells and tandem solar cells.

[0019] Optionally, the series connection includes: taking any two adjacent third cell pieces; connecting the connecting section on the front side of one of the third cell pieces with the connecting section on the back side of the other third cell piece; or, the photovoltaic cell piece is a back-contact cell, the positive and negative electrodes on the back side of the photovoltaic cell piece are both provided with the conductive member, and both ends of the conductive member are extended to the outside of the battery to form a connecting section, and the connecting section on the positive electrode on the back side of one of the third cell pieces is connected to the connecting section on the negative electrode on the back side of the other third battery; the series connection is selected from one or more of welding and overlapping.

[0020] The third aspect of the present invention provides a solar cell module prepared by the method according to the second aspect of the present invention.

[0021] A fourth aspect of the present invention provides a solar cell, comprising the solar cell assembly described in the first aspect of the present invention or the solar cell assembly prepared by the method described in the second aspect of the present invention.

[0022] Through the above technical solution, the present invention lays a conductive part on the battery cell and covers a conductive layer on at least the surface of the conductive part. The conductive part and the conductive layer jointly play the role of collecting the secondary grid current, thereby reducing the shading loss of the welding strip, shortening the process flow, and at the same time reducing the silver consumption and the performance loss caused by flux contamination of the battery cell, eliminating the equipment investment and process costs of traditional welding ends, and realizing a low-temperature metal interconnection process.

[0023] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 Schematic cross-sectional view of a solar cell assembly provided by some embodiments of the present invention.

[0025] Figure 2 Schematic cross-sectional views of solar cell modules according to other embodiments of the present invention.

[0026] Figure 3 Schematic cross-sectional view of some components of a solar cell provided in some embodiments of the present invention.

[0027] Description of reference numerals: 100, upper cover; 200, first film layer; 300, solar cell module; 400, second film layer; 500, back sheet; 310, substrate; 321, auxiliary grid on the light-receiving surface; 330, conductive member; 331, connecting section on the light-receiving surface; 332, connecting section on the backlight surface; 340, main grid. DETAILED DESCRIPTION

[0028] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0029] The first aspect of the present invention provides a solar cell assembly comprising a plurality of cells, Figure 1 The battery cell includes a substrate 310 and a secondary grid 321 located on the substrate 310, a main grid is provided on the secondary grid 321, and the main grid includes a conductive member 340 and a conductive layer coated on at least part of the surface of the conductive member 340; the conductive member includes a main section located on the battery cell and a connecting section with at least one end extending beyond the battery cell, and multiple battery cells are connected in series through the connecting section.

[0030] The main grid provided by the present invention includes a conductive part laid on the battery cell and a conductive layer coated on the surface of the conductive part. The conductive part and the conductive layer jointly play the role of collecting the secondary grid current, reducing the shading loss of the welding strip connection in the existing technology, shortening the process flow, and at the same time reducing the performance loss caused by flux contamination of the battery cell, eliminating the equipment investment and process costs of the traditional welding end, and realizing a low-temperature metal interconnection process.

[0031] In some embodiments, the distance A between two adjacent conductive elements is 0-230 mm. The solar cell assembly provided by the present invention is suitable for preparing multi-busbar cells, for example, cells with 5BB, 6BB, 12BB, 16BB, 20BB, or 24BB busbars, or cells with 0BB (no busbar), a single busbar, or any other number of busbars. For example, in some specific embodiments, the substrate may be 210 mm x 210 mm, and the distance between two adjacent conductive elements may be varied as needed. Increasing the number of conductive elements reduces the distance from the secondary grid to the conductive line, thereby reducing resistance. Preferably, to further improve the photoelectric conversion efficiency of the solar cell, the distance A between two adjacent conductive elements is 0-12 mm, for example, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 12 mm, or any value within the aforementioned ranges, or a range consisting of any values.

[0032] In some embodiments, the conductive member may include a conductive tape and / or a conductive wire.

[0033] In some embodiments, the conductive member may be a conductive wire, and the diameter of the conductive wire may be 0-3 mm. In order to further reduce the light blocking loss of the photovoltaic cell, the diameter of the conductive wire is preferably 0-0.06 mm. For example, in some preferred specific embodiments, the diameter of the conductive wire may be 0.01 mm, 0.016 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm or any value within the aforementioned range.

[0034] In some embodiments, when laying conductive wires with smaller diameters, the conductive wires are straightened before they come into contact with the solar cell. After the main grid is made, the tension of the conductive wires can be released, thereby avoiding drift of the conductive wires during the preparation of solar cell modules and affecting the photoelectric conversion efficiency.

[0035] In some embodiments, the conductive member may be a conductive tape having a width of 0.05-3 mm and a thickness of 0.01-0.5 mm.

[0036] In some embodiments, the conductive member has good conductivity to facilitate the collection of the current of the auxiliary grid. The conductivity of the conductive member is 0.5×10 7 -7.0×10 7 S / m, in order to further improve the efficiency of photovoltaic cells, it is preferably 3×10 7 -7.0×10 7 S / m.

[0037] In some embodiments, the material of the conductive member can be selected from one or more of silver, copper, aluminum, nickel, iron, and plated copper.

[0038] In some embodiments, the lengths of the connecting segments in a plurality of battery cells are equal.

[0039] In some preferred embodiments, the length of the connecting segment (i.e., the length of the conductive member exceeding the battery) is 0-0.4 mm, for example, it can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, or any value within the foregoing range. Preferably, the length of the connecting segment is 0-0.2 mm, so that the battery cells can be connected in series through the connecting segment.

[0040] In the present invention, the busbar can be prepared by printing a conductive paste on the surface of the conductive member, wherein the cross-section of the busbar (the cross-section is perpendicular to the direction in which the busbar extends) changes according to the amount of the printed paste or the change of the screen pattern, for example, Figure 1 As shown, the cross section of the main grid is a trapezoidal shape close to the upper surface.

[0041] In some embodiments, the conductive layer completely covers the surface of the main segment, and the cross-sectional shape of the main grid is selected from one or more of a trapezoid, a square, a circle and a triangle. In order to reduce silver consumption and reduce the shading loss of the main grid, the cross-sectional shape of the main grid is a triangle. It can be understood that when the positive and negative electrodes of the battery cell are on both sides, conductive parts are laid on both sides and printed to form a conductive layer; when the positive and negative electrodes of the battery cell are on the back, conductive parts are laid on both positive and negative electrodes and printed to form a conductive layer. When the cross-sectional shape of the main grid is a triangle, taking the conductive part as a conductive wire as an example, as Figure 2 As shown, the conductive member 340 is in contact with the auxiliary grid 321 (line contact or surface contact), and the conductive layer 330 almost completely covers the conductive member 340. In some other embodiments, such as Figure 1 As shown, the conductive layer 330 is filled between the conductive member 340 and the battery cell (except for the contact position), and fixes the conductive member on the battery cell.

[0042] In some embodiments, the conductive element is laid continuously on the battery cell (i.e., the conductive element laid on a battery cell is uninterrupted) or intermittently. When laid intermittently, it is laid along the direction in which the conductive element extends, and electrical connection is achieved between the two conductive elements through a conductive layer formed by printing.

[0043] In some embodiments, the conductive layer printed on the conductive element can be continuous or discontinuous. When discontinuous, the length of the conductive layer along the extension direction of the conductive element is not particularly limited, as long as the conductive element can conduct current to the secondary grid.

[0044] In some embodiments, the bottom width of the main grid can be 0-60 μm, for example, it can be 10 μm, 20 μm, 30 μm, 35 μm, 40 μm, 50 μm, 60 μm or any value within the aforementioned range, and the height can be 0-24 μm, for example, it can be 4 μm, 6 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, or any value within the aforementioned range. The main grid reduces the shading area of ​​the battery cell, which can significantly reduce the shading loss of the main grid to the battery cell. In order to further improve the photoelectric conversion efficiency, preferably, the bottom width of the main grid is 0-35 μm and the height is 0-20 μm.

[0045] In some embodiments, the width of the auxiliary grid is 3-30 μm, for example, 3 μm, 4 μm, 5 μm, 8 μm, 10 μm, 12 μm, 14 μm, 15 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, or any value within the aforementioned range, and the thickness is 1-20 μm, for example, 1 μm, 3 μm, 5 μm, 6 μm, 7.5 μm, 9 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, or any value within the aforementioned range. A narrower auxiliary grid is beneficial for reducing shading loss. The method provided by the present invention can form good contact with the auxiliary grid to collect current from the auxiliary grid.

[0046] In some embodiments, the material of the secondary grid may be silver, copper, tin, or a tin alloy.

[0047] In some embodiments, the secondary grid includes a secondary grid conductive member and a gate material layer covering the secondary grid conductive member. Preferably, the secondary grid conductive member may be a conductive filament, and the diameter of the secondary grid conductive member may be 0-1 mm. Specifically, the conductive member is made of one or more of silver, copper, and plated copper. By providing the conductive filament in the secondary grid, silver loss can be further reduced.

[0048] In some embodiments, the cell is selected from one or a combination of two of an aluminum back surface field cell, a PERC cell, a TOPCon cell heterojunction cell, a BC cell, a perovskite solar cell, and a tandem solar cell. In the solar cell module provided by the present invention, the conductive member and the main grid formed by the silver paste cooperate to collect the fine grid current, thereby reducing shading losses to the cell and significantly reducing the resistance of the conductive member in contact with the cell.

[0049] A second aspect of the present invention provides a method for preparing a solar cell module, the method comprising the following steps: forming a secondary grid on the surface of the photovoltaic cell to obtain a first cell; Laying a plurality of conductive members at intervals on the surface of the first cell so that the conductive members cross-contact the auxiliary grid to obtain a second cell; wherein at least one end of the conductive member extends to the outside of the cell to form a connecting section; Printing a busbar paste on at least a portion of the surface of the conductive member to form a busbar to obtain a third cell; The third battery cells are connected in series via the connecting sections.

[0050] The present invention first lays a conductive member on the battery cell and then prints a paste on the surface of the conductive member by screen printing to coat the conductive member. This not only reduces the amount of main grid paste used and reduces shading loss, but also achieves good contact between the conductive member and the battery cell, reducing the investment in fixed assets of production equipment.

[0051] In some specific embodiments, the photovoltaic cell is firmly connected to the metal wire, and the problem of conductive member displacement is less likely to occur during operation and transfer of the photovoltaic cell.

[0052] It should be noted that after the photovoltaic cells are connected in series, the current in the cell string needs to be collected through the drain bars. It can be understood that on the photovoltaic cell at the end of the cell string, the conductive parts extend beyond the photovoltaic cell on both sides.

[0053] In some embodiments, when the conductive members are laid, the distance between two adjacent conductive members is 0-230 mm.

[0054] In some embodiments, the conductive member includes a conductive tape and / or a conductive thread, wherein the conductive thread may have a diameter of 0-3 mm, and the conductive tape may have a width of 0.05-3 mm and a thickness of 0.01-0.5 mm.

[0055] In some embodiments, the length of the connecting segment is 0-0.4 mm.

[0056] In some embodiments, the method of forming the main grid by printing on the surface of the conductive member comprises the following steps: making the pattern on the screen correspond to the conductive member on the second battery cell; Placing a busbar slurry on the upper surface of the screen, applying pressure to the busbar slurry so that the busbar slurry is printed on the surface of the cell, to obtain a cell with busbar lines printed thereon; The battery cell printed with the main grid lines is dried to obtain the third battery cell.

[0057] In some embodiments, the main grid paste includes 80-100wt% metal powder and 0-20wt% additives; the metal powder is selected from one or more of silver powder, copper powder, aluminum powder and nickel powder; the additive is selected from one or more of thixotropic agents, binders, curing agents, dispersants, resins and solvents.

[0058] In some embodiments, the busbar slurry has a viscosity of 30-600 Pa·s / 25° C. at 10 rpm. The high viscosity of the busbar slurry allows the conductive member to be bonded to the surface of the photovoltaic cell to collect current in the secondary grid and increase the open circuit voltage of the solar cell.

[0059] In some embodiments, the mesh size of the screen can be selected from one of 280 mesh, 325 mesh, 360 mesh and 400 mesh.

[0060] In some embodiments, the thickness of the screen is 3-30 μm to form a main grid with a suitable thickness.

[0061] In some embodiments, the cross-section of the main grid has a bottom width of 0-60 μm and a height of 0-24 μm. In order to reduce the light-shielding area of ​​the secondary grid on the cell and obtain a narrower secondary grid, a secondary grid paste with good printability and ohmic contact performance is used to print and form the secondary grid.

[0062] In some embodiments, the width of the auxiliary grid may be 3-30 μm, and the thickness may be 1-20 μm, so as to further reduce the light shielding loss of the auxiliary grid.

[0063] In some embodiments, the cell is selected from one or a composite cell of two of aluminum back surface field cells, PERC cells, TOPCon cells, heterojunction cells, BC cells, perovskite solar cells and tandem solar cells.

[0064] In some embodiments, the series connection comprises: Take any two adjacent third battery cells; Connecting the connecting section on the front side of one of the third solar cells to the connecting section on the back side of another of the third solar cells; or, wherein the photovoltaic cell is a back-contact cell, the positive and negative electrodes on the back side of the photovoltaic cell are both provided with the conductive member, and both ends of the conductive member are extended to the outside of the cell to form a connecting section, and connecting the connecting section on the positive electrode on the back side of one of the third solar cells to the connecting section on the negative electrode on the back side of another of the third cells; The series connection is selected from one or more of welding and overlapping.

[0065] In some embodiments, when the positive and negative electrodes of the photovoltaic cell are respectively arranged on the two sides of the cell, Figure 3 As shown, the connecting segment 331 of one of the third battery cells is electrically connected to the connecting segment on the back of another third battery cell, which can be connected by welding or other methods to maintain physical contact. When the series connection is welded, the connecting segment 332 on the back of the other third battery cell is kept in close contact with the connecting segment 331, and the contact portion of the connecting segment 331 and the connecting segment 332 is heated to achieve the series welding of the third battery cells. The aforementioned welding steps are repeated to weld multiple battery cells in series.

[0066] In some other embodiments, when the photovoltaic cell is a BC (back contact) cell, such as an IBC (interdigitated back contact) cell or other back contact cell, both ends of the conductive wire extend beyond the cell to form a connecting segment, connecting the connecting segment on the positive electrode on the back side of one of the third cell cells with the connecting segment on the negative electrode on the back side of another third cell.

[0067] The third aspect of the present invention provides a solar cell module prepared by the method described in the second aspect of the present invention.

[0068] The present invention also provides a solar cell, comprising the solar cell assembly described in the first aspect of the present invention or the solar cell assembly prepared by the method described in the second aspect of the present invention.

[0069] In some embodiments, as Figure 3 The solar cell includes an upper cover plate 100 , a first film layer 200 , the aforementioned solar cell assembly 300 , a second film layer 400 and a back plate 500 .

[0070] The upper cover plate and the back plate may be made of common materials in the art. Preferably, the upper cover plate and the back plate are selected from transparent plates such as glass plates.

[0071] In some specific embodiments, the first film layer and the second film layer can be selected from conventional films in the art. In some preferred embodiments, the first film layer and the second film layer are each selected from one or more of ethylene-vinyl acetate copolymer (EVA), polyethylene octene co-elastomer (POE), and EPE film. Specifically, the EPE film is an EVA-POE-EVA composite structure film prepared by a coextrusion process, wherein the POE film content is approximately 60 wt%.

[0072] Wherein, the solar cell is prepared by the following method: Connect the battery cells in series through bus bars; The backsheet, second film layer, solar cell module, first film layer, and upper cover sheet are stacked in order from bottom to top, and then laminated. During the lamination process, the materials of the first and second adhesive films are cross-linked, wrapping the solar cell module and bonding them to the upper cover sheet and backsheet, respectively. For example, if both the upper cover sheet and the backsheet are made of glass, during lamination, the first film layer is cross-linked and bonded to the upper cover sheet, and the second film layer is cross-linked and bonded to the backsheet.

[0073] It should be noted that the method for preparing the solar cell further comprises: framing the laminated components and connecting them to a junction box, and then performing a colloid curing process on the obtained components.

[0074] It is understandable that cleaning and trimming of the components are also required during the lamination and colloid curing process.

[0075] In the present invention, the cell in the solar cell assembly can be an intermediate product in the solar cell preparation process, and the solar cell can be a composite cell of one or two selected from aluminum back surface field cells, PERC cells, TOPCon cells, heterojunction cells, BC cells, perovskite solar cells and stacked solar cells.

[0076] In some specific embodiments, the solar cell may be a heterojunction cell, and the cell is an intermediate product obtained by cleaning and texturing a silicon wafer, depositing an amorphous silicon thin film, and depositing an ITO thin film.

[0077] In some specific embodiments, the solar cell can be a TOPCon cell, and the cell is an intermediate product obtained after the silicon wafer is cleaned and textured, boron is diffused to form a P+ emitter, the back is alkaline polished, LPCVD is used to form a tunneling oxide layer and an intrinsic polysilicon layer in sequence, phosphorus is diffused to form an N+ polysilicon layer, passivation is performed, and PECVD is used for coating.

[0078] In some specific embodiments, the substrate includes a silicon wafer and a treatment layer on the surface of the silicon wafer. Figure 1As shown, auxiliary grids are provided on both the light-receiving surface and the backlight surface of the substrate 310 .

[0079] The silicon wafer may be selected from intrinsic single crystal silicon and doped single crystal silicon. Specifically, the size of the cell may be 210 mm×210 mm.

[0080] The present invention is further illustrated below by way of examples, but the present invention is not limited thereto.

[0081] In the following examples and comparative examples, the silicon wafer in the cell is a single crystal silicon wafer with a size of 210 mm × 210 mm × 0.11 mm. The specifications of the POE film layer are 2386 mm × 1304 mm, and the gram weight is 400 g / m 2 The melting temperature is 150 ° C. The specifications of the glass plate are 2384 mm × 1303 mm × 2 mm.

[0082] The photovoltaic cell a is prepared by a method comprising the following steps: S1. Take a 110 μm thick N-type single-crystalline silicon wafer (resistivity of 1.5 Ω·cm) and texturize it using a solution containing a texturizing additive and potassium hydroxide, forming a pyramid texture with a reflectivity of less than 10% on both sides of the single-crystalline silicon wafer. S2, sequentially depositing an intrinsic amorphous silicon layer and an N-type doped amorphous silicon layer on the light-receiving side, and sequentially depositing an intrinsic amorphous silicon layer and a P-type doped amorphous silicon layer on the backlight side; S3. Depositing a transparent conductive film ITO layer on the surface of the N-type doped amorphous silicon layer and the surface of the P-type doped amorphous silicon layer.

[0083] The photovoltaic cell b is prepared by a method comprising the following steps: S1. Take a 130 μm thick N-type single-crystalline silicon wafer (resistivity of 2 Ω·cm) and texturize it using a solution containing a texturizing additive and potassium hydroxide, forming a pyramid texture with a reflectivity of less than 10% on both sides of the single-crystalline silicon wafer. S2, boron diffusion, forming a P+ emitter on the light-receiving side of the silicon wafer, and alkaline polishing the back side of the silicon wafer with the oxide layer formed by the boron diffusion; S3. Forming a 1.5 nm thick tunnel oxide layer (SiO2) and a 120 nm thick intrinsic amorphous silicon layer on the back side by low pressure chemical vapor deposition (LPCVD) in sequence; S4, performing phosphorus diffusion treatment on the intrinsic amorphous silicon layer formed on the back side; S5, depositing AlO with a thickness of 4 nm on the light-receiving surface of the semiconductor with the P+ emitter x (Aluminum oxide) passivation layer; S6, by PECVD on AlO x A SiN layer with a thickness of 75 nm is formed on the surface of the passivation layer (aluminum oxide). x (Silicon nitride) anti-reflection coating.

[0084] Example 1 This embodiment is used to illustrate the method for preparing a solar cell module of the present invention, which includes: (1) Screen printing is used to print a secondary grid paste on the light-receiving surface and the backlight surface of a photovoltaic cell a, and the secondary grid is dried at 180°C to form secondary grids on both sides of the photovoltaic cell a to obtain a first cell; wherein the secondary grid has a width of 18 μm and a thickness of 7.5 μm; the distance between two adjacent secondary grids is 22 μm, or more than 180 secondary grids are formed on the cell; the secondary grid paste includes 90 wt% of silver powder and 10 wt% of additives; (2) Multiple conductive wires made of copper (conductivity of 5.71×10 7 S / m) are laid on one surface of the first cell, so that the conductive filaments are perpendicular to the auxiliary grid of the light-receiving surface, the conductive filaments are parallel to each other, and one end of the conductive filaments is extended to the outside of the first cell to form a connecting segment, thereby obtaining a second cell; the diameter of the conductive filaments is 0.03 mm; the distance between two adjacent conductive filaments is 8.5 mm; and the length of the connecting segment is 0.2 mm; (3) placing a screen above the second cell obtained in step (2), and making the pattern on the screen correspond to each conductive wire one by one, placing a main grid paste on the upper surface of the screen, applying pressure to the main grid paste so that the main grid paste is printed on the surface of the second cell, drying and curing at 200°C, forming a main grid with a roughly trapezoidal cross-section on the second cell, and forming main grids on both sides of the cell by combining the laying of conductive wires and the printing of main grid paste, and the connecting section on the backlight side and the connecting section on the light-receiving side are respectively on both sides of the cell, to obtain a third cell; the main grid paste includes 90 wt% of silver powder and 10 wt% of an additive; the viscosity of the main grid paste at 10 rpm is 260 Pa·s / 25°C; the bottom width of the main grid is 35 μm and the height is 20 μm; (4) Arrange 66 third battery cells in an array, connect the conductive wires of the third battery cells to the connecting sections on the back of adjacent third battery cells by welding, and connect the resulting battery strings through bus bars; (5) stacking the back glass, the second film layer POE layer, the battery string obtained in step (4), the first film layer POE layer and the upper cover glass in sequence from bottom to top, and laminating them so that the first film layer POE layer and the second film layer POE layer are cross-linked; the lamination conditions include: the temperature is 145 °C.

[0085] Example 2 This embodiment prepares a solar cell according to Example 1, except that: In step (2), the distance between two adjacent conductive threads is 9.0 mm.

[0086] Example 3 This embodiment prepares a solar cell according to Example 1, except that: In step (2), the distance between two adjacent conductive filaments is 10 mm. The bottom width of the main grid is 35 μm and the height is 20 μm.

[0087] Example 4 This embodiment prepares a solar cell according to Example 1, except that: In step (2), the distance between two adjacent conductive threads is 11 mm.

[0088] Example 5 This embodiment prepares a solar cell according to Example 1, except that: In step (2), the distance between two adjacent conductive filaments is 12 mm. The bottom width of the main grid is 35 μm and the height is 20 μm.

[0089] Example 6 This embodiment prepares a solar cell according to Example 1, except that: In step (2), the distance between two adjacent conductive threads is 13 mm.

[0090] Example 7 The solar cell prepared in this embodiment is based on the reference embodiment 1, except that in step (2), the diameter of the conductive filament is 0.016 mm.

[0091] Example 8 The solar cell prepared in this embodiment is based on Example 1, except that: the diameter of the conductive filament in step (2) is 0.016 mm; In step (3), the bottom width of the main gate is 40 μm and the height is 24 μm.

[0092] Example 9 The solar cell prepared in this embodiment is similar to that in Example 1, except that the width of the auxiliary grid is 15 μm.

[0093] Example 10 The solar cell prepared in this embodiment is similar to that in Example 1, except that the width of the auxiliary grid is 12 μm.

[0094] Example 11 The solar cell prepared in this embodiment is similar to that in Example 1, except that the width of the auxiliary grid is 10 μm.

[0095] Example 12 The solar cell prepared in this embodiment is prepared in accordance with Example 1, except that: in step (1), a photovoltaic cell b is used to prepare the solar cell; and the width of the secondary grid is 18 μm.

[0096] Example 13 This embodiment prepares a solar cell according to Example 1, except that: In step (1), before printing the secondary grid paste, a secondary grid conductive wire (made of copper and having a diameter of 0.01 mm) is laid on the light-receiving surface of the photovoltaic cell, and then the secondary grid paste is printed on the surface of the secondary grid conductive wire by screen printing.

[0097] Comparative Example 1 This comparative example prepares a solar cell according to Example 1, except that: Step (2) is omitted, i.e., the main grid is directly formed by screen printing on the surface of the first cell with the auxiliary grid, and the multiple cells are connected by welding with a welding ribbon. The bottom width of the main grid formed by screen printing is 35 μm and the height is 20 μm.

[0098] Comparative Example 2 The solar cell prepared in this comparative example is prepared according to comparative example 1, except that: in step (1), photovoltaic cell b is used to prepare the solar cell; and the width of the secondary grid is 22 μm.

[0099] Performance Testing The solar cells prepared in the above examples and comparative examples were tested according to the method disclosed in IEC904-1. Test equipment: single flash simulator. Test conditions: light intensity of 1000 W / m 2 The spectrum is AM1.5 and the temperature is 25° C. The performance test results of each solar cell are recorded, as shown in Table 1.

[0100] Table 1

[0101] From the data in the above table, it can be found that the present invention can reduce the amount of busbar paste used, reduce shading loss, and achieve good contact between the conductive member and the battery cell by laying a conductive member on the battery cell and printing the busbar paste on the conductive member to form a conductive layer.

[0102] The preferred embodiments of the present disclosure are described in detail above. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0103] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0104] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A solar cell module, characterized in that: The invention comprises a plurality of battery cells, each of which comprises a substrate and a secondary grid located on the substrate; a main grid is provided on the secondary grid, and the main grid comprises a conductive member and a conductive layer coated on at least a portion of the surface of the conductive member; the conductive member comprises a main section located on the battery cell and a connecting section with at least one end extending beyond the battery cell, and the plurality of battery cells are connected in series through the connecting section.

2. The solar cell module according to claim 1, wherein The distance A between two adjacent conductive members is 0-230 mm, preferably 0-12 mm.

3. The solar cell module according to claim 1 or 2, wherein: The conductive member includes a conductive tape and / or a conductive wire; The diameter of the conductive filament is 0-3 mm, preferably 0-0.06 mm; and / or The conductive tape has a width of 0.05-3 mm and a thickness of 0.01-0.05 mm.

4. The solar cell module according to claim 1 or 2, wherein: The electrical conductivity of the conductive member is 0.5×10 7 -7.0×10 7 S / m; The material of the conductive member is selected from one or more of silver, copper, aluminum, nickel, iron and plated copper.

5. The solar cell module according to claim 1, wherein The lengths of the connecting sections in the plurality of battery cells are equal; The length of the connecting section is 0-0.4 mm.

6. The solar cell module according to claim 1, wherein The conductive layer completely covers the surface of the main segment, and the cross-sectional shape of the main grid is selected from one or more of a trapezoidal, square, circular and triangular shape; or, the conductive layer is filled between the conductive member and the substrate; Preferably, the cross-section of the main grid is triangular, the bottom width of the main grid is 0-60 μm, preferably 0-35 μm, and the height is 0-24 μm, preferably 0-20 μm.

7. The solar cell module according to claim 1, wherein The width of the auxiliary grid is 3-30 μm and the thickness is 1-20 μm; Optionally, the auxiliary grid includes an auxiliary grid conductive member and a gate material layer covering the auxiliary grid conductive member; the auxiliary grid conductive member is a conductive wire, and the diameter of the auxiliary grid conductive member is 0-1 mm.

8. The solar cell module according to claim 1, wherein The cell is selected from one or a composite cell of two of aluminum back surface field cells, PERC cells, TOPCon cells, heterojunction cells, BC cells, perovskite solar cells and stacked solar cells.

9. A method for preparing a solar cell module, characterized in that: The method comprises the following steps: forming a secondary grid on the surface of the photovoltaic cell to obtain a first cell; Laying a plurality of conductive members on the surface of the first cell so that the conductive members cross-contact the auxiliary grid to obtain a second cell; wherein at least one end of the conductive member extends to the outside of the first cell to form a connecting section; Printing a busbar paste on at least a portion of the surface of the conductive member to form a busbar to obtain a third cell; The third battery cells are connected in series via the connecting sections.

10. The method according to claim 9, wherein: When laying the conductive members, the distance between two adjacent conductive members is 0-230 mm; The conductive member includes a conductive tape and / or a conductive wire; The conductive filament has a diameter of 0-3 mm; and / or The conductive tape has a width of 0.05-3 mm and a thickness of 0.01-0.05 mm; Optionally, the length of the connecting segment is 0-0.4 mm.

11. The method according to claim 9, wherein The method for forming the main grid by printing on the surface of the conductive member comprises the following steps: making the pattern on the screen correspond to the conductive member on the second battery cell; Placing a busbar slurry on the upper surface of the screen, applying pressure to the busbar slurry so that the busbar slurry is printed on the surface of the second cell, to obtain a cell with busbar lines printed thereon; The battery cell printed with the main grid lines is dried to obtain the third battery cell.

12. The method according to claim 10, wherein: The busbar slurry comprises 80-100 wt% of metal powder and 0-20 wt% of an additive; the metal powder is selected from one or more of silver powder, copper powder, aluminum powder and nickel powder; the additive is selected from one or more of a thixotropic agent, a binder, a curing agent, a dispersant, a resin and a solvent; The viscosity of the busbar slurry at 10 rpm is 30-600 Pa·s / 25°C.

13. The method according to claim 8, wherein The bottom width of the main grid is 0-60 μm and the height is 0-24 μm; The width of the auxiliary grid is 3-30 μm, and the thickness is 1-20 μm.

14. The method according to claim 8, wherein The cell is selected from one or a composite cell of two of aluminum back surface field cells, PERC cells, TOPCon cells, heterojunction cells, BC cells, perovskite solar cells and stacked solar cells.

15. The method according to claim 8 or 14, wherein The series connection comprises: Take any two adjacent third battery cells; Connecting the connecting section on the front side of one of the third solar cells to the connecting section on the back side of another of the third solar cells; or, wherein the photovoltaic cell is a back-contact cell, the positive and negative electrodes on the back side of the photovoltaic cell are both provided with the conductive member, and both ends of the conductive member are extended to the outside of the cell to form a connecting section, and connecting the connecting section on the positive electrode on the back side of one of the third solar cells to the connecting section on the negative electrode on the back side of another of the third cells; The series connection is selected from one or more of welding and overlapping.

16. A solar cell module prepared according to the method according to any one of claims 8 to 15.

17. A solar cell, characterized in that: The invention comprises the solar cell module according to any one of claims 1 to 7 or the solar cell module prepared by the method according to any one of claims 8 to 15.

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