Back contact solar cell, preparation method therefor, and photovoltaic module

Abstract

Disclosed are a back contact solar cell, a preparation method therefor, and a photovoltaic module, related to the technical field of photovoltaics. The back contact solar cell comprises a silicon substrate having a first surface, wherein the first surface comprises: a first conductive area, a second conductive area, and an insulating area located between the first conductive area and the second conductive area; a first transmission layer, located on the first conductive area and the insulating area; a barrier layer, located in the insulating area on the first transmission layer; a second transmission layer, located on the barrier layer and the second conductive area; and a transparent conductive layer, located on the second transmission layer and the exposed first transmission layer, wherein a part of the transparent conductive layer located in the insulating area is provided with an insulating opening, and the insulating opening electrically isolates the first transmission layer from the second transmission layer. Through the arrangement of the insulation opening, insulation reliability is better.

Description

Back contact solar cell and preparation method thereof and photovoltaic module

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on June 19, 2023, with application number 202310728616.X, and invention name “A back-contact solar cell, its preparation method and photovoltaic module”, and the Chinese patent application filed with the Patent Office of China on June 19, 2023, with application number 202310729476.8, and invention name “A back-contact solar cell, its preparation method and photovoltaic module”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of photovoltaic technology, and in particular to a back-contact solar cell and a preparation method thereof, and a photovoltaic module. Background Art

[0003] Solar cells are devices that directly convert sunlight into electricity. After decades of development, crystalline silicon solar cells currently hold a commanding position in the photovoltaic cell market, primarily due to their widespread availability of raw materials, high reliability, high power generation efficiency, and low cost. Crystalline silicon cells currently include various types, including passivated emitter and rear cell (PERC), tunneling oxide passivated contact (TOPcon), and heterojunction (SHJ) cells. Among them, crystalline silicon-amorphous silicon heterojunction (SHJ) solar cells, due to their symmetrical structure, high open-circuit voltage, low processing temperature, and excellent temperature characteristics, have gradually become one of the mainstream technologies for crystalline silicon cells, attracting significant attention from both industry and academia. Currently, certified large-area cell efficiencies have reached 26.3%. TOPcon cells, on the other hand, have achieved efficiencies of 25.7%, similarly offering the advantage of low cost. However, SHJ and TOPcon cells still have some challenges. The light-entering surface of the cell is obstructed by grid lines, reducing the cell's absorption of sunlight, resulting in significant short-circuit current losses. This is a common problem faced by nearly all silicon-based solar cells. Therefore, the research on solar cells without electrodes on the light-entering side is particularly important. Based on this, back-contact solar cells can solve this problem because their electrodes are located on the back of the cell, minimizing the short-circuit current loss caused by the upper surface. In this cell structure, there are no grid lines on the front, and the entire area is used to absorb sunlight; the back of the cell is provided with an electron-selective transport layer and a hole-selective transport layer. The mainstream arrangement currently used is the "comb-like" interdigitated back contact arrangement, referred to as IBC solar cells. Therefore, the back-contact heterojunction solar cell (SHJ-IBC) can be referred to as HBC cell, and the back-contact tunneling oxide passivation contact cell (TOPcon-IBC) can be referred to as TBC.

[0004] Application Contents

[0005] The present application provides a back-contact solar cell and a preparation method thereof, and a photovoltaic module, aiming to solve the problem of poor insulation effect in existing back-contact solar cells.

[0006] In a first aspect of the present application, a back-contact solar cell is provided, comprising:

[0007] A silicon substrate having a first surface; the first surface comprising a first conductive region, a second conductive region, and an insulating region between the first conductive region and the second conductive region;

[0008] a first transmission layer, located on the first conductive region and the insulating region;

[0009] a barrier layer located in the insulating region on the first transmission layer;

[0010] a second transmission layer, located on the barrier layer and the second conductive region;

[0011] a transparent conductive layer, located on the second transmission layer and the exposed first transmission layer;

[0012] An insulating opening is formed in a portion of the transparent conductive layer located in the insulating region; the insulating opening electrically isolates the first transmission layer from the second transmission layer.

[0013] In the embodiment of the present application, the insulation reliability and insulation effect are improved by providing the insulation opening.

[0014] Optionally, at least two insulating openings are formed in portions of the transparent conductive layer and the second transmission layer located in the insulating region; the insulating openings each extend from the transparent conductive layer toward the silicon substrate and extend at most to a surface of the barrier layer close to the silicon substrate;

[0015] The insulating openings include at least one first insulating opening, and at least the first insulating opening electrically isolates the first transmission layer from the second transmission layer.

[0016] In the embodiment of the present application, the transparent conductive layer and the portion of the second transmission layer located in the insulating area are each formed with at least two insulating openings. The greater the number of insulating openings, the better the insulation reliability and the better the insulation effect. Among the insulating openings, there is at least one first insulating opening. At least the first insulating opening electrically isolates the first transmission layer and the second transmission layer. A good insulation effect is ensured by at least the first insulating opening. The remaining insulating openings play a good insulation supplementary role to the first insulating opening, and the insulation effect is better. All insulating openings extend from the transparent conductive layer to the silicon substrate and extend at most to the surface of the barrier layer close to the silicon substrate. In the back-contact solar cell, a first transmission layer is also provided between the barrier layer and the silicon substrate. The insulating openings extend at most to the surface of the barrier layer close to the silicon substrate, that is, the insulating openings do not destroy the first transmission layer between the barrier layer and the silicon substrate. The first transmission layer maintains good electrical properties and passivation properties, etc. In summary, the back-contact solar cell of the present application has a better insulation effect and a higher photoelectric conversion efficiency.

[0017] Optionally, the insulating opening further includes at least one second insulating opening, the depth of the second insulating opening is less than or equal to the depth of the first insulating opening, and the second insulating opening is closer to the edge of the barrier layer than the first insulating opening.

[0018] Optionally, the back-contact solar cell further comprises: a first electrode located on the transparent conductive layer, in the first conductive region;

[0019] Along the extension direction of the first electrode, in the insulating openings, the second insulating openings are symmetrically distributed on both sides of the first insulating opening.

[0020] Optionally, among the insulating openings, the second insulating openings are all distributed on one side of the first insulating opening.

[0021] Optionally, among all the insulating openings, the distance between the first insulating opening and its adjacent second insulating opening is 1 micron to 1000 microns.

[0022] Optionally, the first conductive regions and the second conductive regions are alternately distributed in a first direction; in the first direction, a size of the second insulating opening is 1 micron to 1000 microns.

[0023] Optionally, in the insulating openings, a distance between adjacent second insulating openings is 1 micron to 1000 microns.

[0024] Optionally, among the insulating openings: the number of the second insulating openings is greater than 1, and the type of shapes of the orthographic projections of the second insulating openings on the surface parallel to the surface of the transparent conductive layer away from the silicon substrate is greater than or equal to 1.

[0025] Optionally, the orthographic projection of the second insulating opening on a surface parallel to a surface of the transparent conductive layer away from the silicon substrate is in the shape of an ellipse or a square.

[0026] Optionally, all of the first insulating openings penetrate the second transmission layer on the barrier layer and extend into the barrier layer.

[0027] Optionally, the insulating openings all penetrate the second transmission layer on the barrier layer and extend into the barrier layer.

[0028] Optionally, in the insulating region, both sides of the insulating opening have reflective components; and the intersection contour of the reflective component and the insulating opening has a portion extending into the insulating opening.

[0029] In the embodiment of the present application, reflective components are provided on both sides of the insulating opening within the insulating region. The intersection of the reflective components and the insulating opening includes a portion extending into the insulating opening. The reflective components and the portion of the reflective components extending into the insulating opening provide a larger reflective surface, thereby improving light reflection from the backlight surface of the back-contact solar cell, increasing the utilization of sunlight, and thereby improving the photoelectric conversion efficiency of the back-contact solar cell.

[0030] Optionally, the transparent conductive layer has a first flange near the insulating opening; the first flange is folded in a direction away from the insulating opening.

[0031] Optionally, the intersection profile has a second flange.

[0032] Optionally, the intersection contour is composed of a plurality of intersecting sub-contours, and the reflective component further has an extended edge located in the insulating opening, continuous with the intersection points of adjacent sub-contours, and extending further into the insulating opening.

[0033] Optionally, the extended edge has a third flange.

[0034] Optionally, the first conductive area and the second conductive area are alternately distributed in the first direction; the maximum distance between the intersection point and the adjacent intersection contour in the first direction is less than half of the maximum width of the insulating opening; the direction of the width is parallel to the first direction.

[0035] Optionally, the intersection contour is in the shape of an arc or a straight edge.

[0036] Optionally, the first transmission layer and the second transmission layer are alternately arranged on the silicon substrate; the barrier layer is located on an end region of the first transmission layer close to the second transmission layer; the second transmission layer further has an island portion covering the barrier layer; the transparent conductive layer covers the portion of the first transmission layer not covered by the barrier layer, and covers the second transmission layer;

[0037] The insulating opening penetrates the transparent conductive layer and extends into the isolated island portion. The insulating opening at most extends to the surface of the barrier layer close to the silicon substrate.

[0038] Optionally, the insulating opening penetrates the island portion and extends into the barrier layer.

[0039] Optionally, the insulating opening is formed by laser melting at least a portion of the transparent conductive layer and at least a portion of the island portion; the back-contact solar cell also includes: a mixed layer formed by a laser-melted substance; the mixed layer is located on the barrier layer, and the insulating opening penetrates the mixed layer and extends into the barrier layer; the intersection contour is composed of several intersecting sub-contours, and adjacent sub-contours are tangent to each other.

[0040] Optionally, the first transmission layer includes: a back first passivation layer and a first doping layer stacked together; the back first passivation layer is closer to the silicon substrate than the first doping layer; the second transmission layer includes: a back second passivation layer and a second doping layer stacked together; the back second passivation layer is closer to the silicon substrate than the second doping layer; the first doping layer and the second doping layer have different doping types;

[0041] The materials of the first back passivation layer and the second back passivation layer are both selected from amorphous silicon; the materials of the first doping layer and the second doping layer are both selected from doped amorphous silicon or doped microcrystalline silicon;

[0042] Alternatively, the materials of the first back passivation layer and the second back passivation layer are both selected from silicon oxide; the materials of the first doping layer and the second doping layer are both selected from doped polycrystalline silicon or doped microcrystalline silicon;

[0043] Alternatively, the materials of the first back passivation layer and the second back passivation layer are respectively selected from amorphous silicon or silicon oxide, and the materials of the first doping layer and the second doping layer are respectively selected from doped polycrystalline silicon or doped microcrystalline silicon.

[0044] Optionally, the back contact solar cell further comprises:

[0045] a first electrode, located on the transparent conductive layer, in the first conductive region;

[0046] a second electrode, located on the transparent conductive layer, in the second conductive region;

[0047] The silicon substrate has a second surface opposite to the first surface. The back-contact solar cell further includes a front passivation layer and a front anti-reflection layer sequentially stacked on the second surface of the silicon substrate.

[0048] In a second aspect of the present application, a method for preparing any of the aforementioned back-contact solar cells is provided, comprising:

[0049] Step S1, providing a conductive substrate; the conductive substrate comprises: a silicon substrate; the silicon substrate has a first surface; the first surface comprises: a first conductive region, a second conductive region, and an insulating region located between the first conductive region and the second conductive region; a first transmission layer located on the first conductive region and the insulating region; a barrier layer located in the insulating region on the first transmission layer; a second transmission layer located on the barrier layer and the second conductive region; and a transparent conductive layer located on the second transmission layer and the exposed first transmission layer.

[0050] Step S2: forming an insulating opening on the portion of the transparent conductive layer located in the insulating region by using a laser.

[0051] Optionally, step S2 includes:

[0052] A laser including a main light spot is used to irradiate the portion of the transparent conductive layer located in the insulating area to form at least two insulating openings in the transparent layer and the second transmission layer located in the insulating area, and the first insulating opening is formed at the position irradiated by the main light spot.

[0053] Optionally, the main light spot moves along the second direction to illuminate the portion of the transparent conductive layer located in the insulating region. Before step S2, the method further includes: adjusting the optical path of the laser so that the laser further includes: at least one diffraction light spot located on at least one side of the main light spot in a third direction perpendicular to the second direction; step S2 includes:

[0054] A laser including the main light spot and the diffraction light spot is used to move and irradiate along the second direction, so as to form at least two insulating openings in the portion of the transparent conductive layer located in the insulating area, and in the portion of the transparent layer and the second transmission layer located in the insulating area, and the position where the main light spot irradiates forms a first insulating opening, and the position where the diffraction light spot irradiates forms a second insulating opening.

[0055] Optionally, the diffraction spots are distributed around the main spot.

[0056] Optionally, in the second direction, adjacent diffraction spots are at least tangent to each other; or, in the second direction, adjacent diffraction spots are distributed at intervals.

[0057] Optionally, the distance between the main light spot and the adjacent diffraction light spot is: 1 micron to 1000 microns;

[0058] And / or, in the third direction, the size of the diffraction spot is: 1 micron to 1000 microns;

[0059] And / or, in the second direction, adjacent diffraction spots are distributed at intervals, and the distance between adjacent diffraction spots is: 1 micron to 1000 microns.

[0060] And / or, the number of all the diffraction spots is greater than 1, and the types of shapes of all the diffraction spots are greater than or equal to 1.

[0061] Optionally, the shape of the diffraction spot is: elliptical or square.

[0062] Optionally, adjacent light spots of the laser are at least tangent to each other, and the shape of the light spots of the laser is quasi-circular.

[0063] Optionally, the laser is at least one of an infrared laser, a green laser and an ultraviolet laser.

[0064] Optionally, the wavelength of the laser is at least one of 355 nm, 532 nm, and 1064 nm;

[0065] and / or, the laser pulse width is 50 ps to 100 ns;

[0066] And / or, the energy of the laser is 0.1W to 50W.

[0067] In a third aspect of the present application, a photovoltaic module is provided, comprising: a plurality of any of the aforementioned back-contact solar cells.

[0068] The above-mentioned back-contact solar cell preparation method and photovoltaic module have the same or similar beneficial effects as any of the aforementioned back-contact solar cells. To avoid repetition, they are not described here. The above description is only an overview of the technical solution of this application. In order to more clearly understand the technical means of this application, it can be implemented in accordance with the contents of the specification. In addition, in order to make the above-mentioned and other purposes, features and advantages of this application more obvious and easy to understand, the specific implementation methods of this application are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0070] FIG1 shows a schematic structural diagram of a back-contact solar cell according to an embodiment of the present application;

[0071] 2 to 7 are schematic diagrams showing steps for preparing a back-contact solar cell according to an embodiment of the present application;

[0072] FIG8 shows a schematic diagram of a first type of laser in an embodiment of the present application;

[0073] FIG9 shows a schematic diagram of a second laser in an embodiment of the present application;

[0074] FIG10 shows a schematic diagram of a third laser in an embodiment of the present application;

[0075] FIG11 is a schematic diagram of a fourth laser according to an embodiment of the present application;

[0076] FIG12 shows a schematic diagram of the fifth laser in an embodiment of the present application;

[0077] FIG13 shows a schematic diagram of a sixth type of laser in an embodiment of the present application;

[0078] FIG14 shows a schematic diagram of the seventh laser in the embodiment of the present application;

[0079] FIG15 shows a schematic diagram of an eighth type of laser in an embodiment of the present application;

[0080] FIG16 is a schematic diagram showing a first type of laser movement in an embodiment of the present application;

[0081] FIG17 is a schematic diagram showing a second laser movement in an embodiment of the present application;

[0082] FIG18 shows a microscope image of a laser-formed insulating opening according to an embodiment of the present application;

[0083] FIG19 shows a schematic structural diagram of another back-contact solar cell in an embodiment of the present application;

[0084] FIG20 shows a schematic diagram of a partial top view of the structure of a first back-contact solar cell according to an embodiment of the present application;

[0085] FIG21 shows a schematic diagram of a partial top view of the structure of a second back-contact solar cell according to an embodiment of the present application;

[0086] FIG22 shows a schematic diagram of a partial top view of the structure of a third back-contact solar cell according to an embodiment of the present application;

[0087] FIG23 shows a schematic diagram of a partial top view of the structure of a fourth back-contact solar cell according to an embodiment of the present application;

[0088] FIG24 is a schematic diagram showing light reflection from the backlight surface of a back-contact solar cell according to an embodiment of the present application;

[0089] FIG25 is a partial enlarged schematic diagram of an insulating opening of a back-contact solar cell in an embodiment of the present application;

[0090] FIG26 shows a scanning electron microscope image of an insulating opening of a back-contact solar cell according to an embodiment of the present application;

[0091] FIG27 is a schematic diagram showing light reflection from a first flange of a back-contact solar cell according to an embodiment of the present application;

[0092] FIG28 shows a scanning electron microscope image of an insulating opening of another back-contact solar cell in an embodiment of the present application;

[0093] 2 to 6 and FIG. 29 show schematic diagrams of the preparation steps of another back-contact solar cell in an embodiment of the present application.

[0094] Explanation of the accompanying drawings: 1-silicon substrate, 111-first surface of the silicon substrate, 222-second surface of the silicon substrate, 2-first back passivation layer, 3-first doping layer, 4-blocking layer, 5-mask layer, 6-first opening, 7-second back passivation layer, 8-second doping layer, 9-front passivation layer, 10-front anti-reflection layer, 11-second opening, 12-transparent conductive layer, 121-first flange, 13-first insulating opening, 14-first electrode, 15-second insulating opening, 17-reflective component, 171-intersection contour, 1711-portion of the reflective component extending into the insulating opening, 1712-intersection of adjacent sub-contours, 1713-second flange, 172-extended edge, 18-mixing layer, 16-second electrode, 2-main light spot, 21-diffraction spot, 22-diffraction spot band. Specific embodiments

[0095] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0096] Referring to Figure 1 , a back-contact solar cell may include a silicon substrate 1. The silicon substrate 1 has a first surface 111. In a back-contact solar cell, the first surface of the silicon substrate 1 is the surface of the silicon substrate 1 closer to the electrodes. The first surface 111 includes a first conductive region, a second conductive region, and an insulating region located between the first and second conductive regions. As shown in Figure 1 , the areas to the left of the dashed line L2 and to the right of the dashed line L3 on the first surface 111 are the sum of the first conductive region and the insulating region, while the area between the dashed lines L2 and L3 is the second conductive region. The first and second conductive regions are alternately distributed along a first direction L1. As shown in Figure 19 , the areas between the dashed lines L2 and L3 and between the dashed lines L4 and L5 on the first surface 111 of the silicon substrate 1 are both insulating regions. The areas to the left of the dashed line L2 and to the right of the dashed line L5 are both first conductive regions, while the area between the dashed lines L3 and L4 is the second conductive region. It should be noted that, in the back-contact solar cell, the dotted lines L2 , L3 , L4 and L5 do not actually exist, and are only used to represent the first conductive region, the second conductive region and the insulating region.

[0097] The first transmission layer, second transmission layer, barrier layer 4, and transparent conductive layer 12 are all located on the first side of the silicon substrate 1. The doping type of the silicon substrate 1 can be N-type doping or P-type doping, and the doping type of the silicon substrate 1 is not specifically limited. The second surface 222 and the first surface 111 of the silicon substrate 1 are arranged relative to each other. The first transmission layer and the second transmission layer have different doping types, that is, one is N-type doping and the other is P-type doping.

[0098] Referring to Figure 1 , a first transmission layer is located on the first conductive region and the insulating region of the first surface 111 of a silicon substrate 1. A barrier layer 4 is located in the insulating region on the first transmission layer, or alternatively, the barrier layer 4 is located in an end region of the first transmission layer near the second conductive region. A second transmission layer is located on the barrier layer 4 and the second conductive region on the first surface 111 of the silicon substrate 1. A transparent conductive layer 12 is located on the second transmission layer and the exposed first transmission layer. The portion of the transparent conductive layer 12 located in the insulating region is formed with an insulating opening, which electrically isolates the first transmission layer from the second transmission layer. The provision of the insulating opening improves insulation reliability and effectiveness.

[0099] Optionally, at least two insulating openings are formed in the portions of the transparent conductive layer 12 and the second transmission layer located in the insulating region. Specifically, at least two insulating openings are formed in the transparent layer 12 and the second transmission layer located on the barrier layer 4. A greater number of insulating openings results in greater insulation reliability and a better insulation effect. As shown in FIG1 , three insulating openings are formed in the transparent conductive layer 12 and the second transmission layer located on the barrier layer 4 on the left, and three insulating openings are formed in the transparent conductive layer 12 and the second transmission layer located on the right. The greater number of insulating openings in the transparent conductive layer 12 and the second transmission layer located on the barrier layer 4 results in greater insulation reliability and a better insulation effect.

[0100] All insulating openings extend from the transparent conductive layer 12 toward the silicon substrate 1 and, at most, extend to the surface of the barrier layer 4 near the silicon substrate 1. If the insulating openings extend into the barrier layer 4, the barrier layer 4 is partially etched to form grooves, which improves the insulation effect. At the same time, since the grooves are formed on the surface of the barrier layer 4, the reflectivity of light is increased, which helps to improve the efficiency of the cell. In the back-contact solar cell, a first transmission layer is also provided between the barrier layer 4 and the silicon substrate 1. The insulating openings extend, at most, to the surface of the barrier layer 4 near the silicon substrate 1. That is, the insulating openings do not damage the first transmission layer between the barrier layer 4 and the silicon substrate 1, and the first transmission layer maintains good electrical properties and passivation properties.

[0101] Among all the insulating openings, there is at least one first insulating opening 13, which at least penetrates the transparent conductive layer 12. At least the first insulating opening 13 electrically isolates the first transmission layer from the second transmission layer. A good insulation effect is ensured by at least one first insulating opening 13, and the remaining insulating openings play a good insulating supplementary role to the first insulating opening 13, resulting in a better insulation effect.

[0102] In summary, the back-contact solar cell of the present application has better insulation effect and higher photoelectric conversion efficiency.

[0103] Referring to Figure 1 , all insulating openings optionally include at least one second insulating opening 15. The depth of the second insulating opening 15 is less than or equal to the depth of the first insulating opening 13, and the second insulating opening 15 is closer to the edge of the barrier layer than the first insulating opening 13. This distribution of insulating openings is easy to manufacture and provides a better insulation effect. As shown in Figure 1 , the depth of the second insulating opening 15 is equal to the depth of the first insulating opening 13. Both second insulating openings 15 extend from the transparent conductive layer 12 toward the silicon substrate 1 and penetrate the transparent conductive layer 12 and the second transmission layer. Of all insulating openings located on the left barrier layer 4, the left second insulating opening 15 is closer to the left end of the left barrier layer 4, while the right second insulating opening 15 is closer to the right end of the left barrier layer 4.

[0104] Referring to Figure 1, optionally, the back-contact solar cell further includes: a first electrode 14, located on the transparent conductive layer 12, and a first conductive region. The extension direction of the first electrode 14 is perpendicular to the paper surface. Along the extension direction of the first electrode 14, among all the insulating openings, the second insulating openings 15 are symmetrically distributed on both sides of the first insulating opening 13, and then along the extension direction of the first electrode 14, the second insulating openings 15 on both sides have a comparable insulating supplementary effect on the first insulating opening 13, further improving the insulation performance. For example, in Figure 1, three insulating openings are provided on the transparent conductive layer 12 and the second transmission layer on the barrier layer 4 on the left. Along the extension direction of the first electrode 14, the two second insulating openings 15 are symmetrically distributed on both sides of the first insulating opening 13. Along the extension direction of the first electrode 14, the two second insulating openings 15 on both sides have a comparable insulating supplementary effect on the first insulating opening 13, further improving the insulation performance.

[0105] Optionally, among all the insulating openings, each second insulating opening 15 is distributed on one side of the first insulating opening 13. The setting of each insulating opening is flexible and diverse, and each second insulating opening 15 plays a good insulating supplementary role to the first insulating opening 13, further improving the insulation performance.

[0106] Optionally, referring to Figure 1 , among all insulating openings, the distance D1 between a first insulating opening 13 and its adjacent second insulating opening 15 is between 1 micron and 1000 microns. Within this distance range, the second insulating opening 15 provides better insulation complement to its adjacent first insulating opening 13, further improving insulation performance. It should be noted that a smaller D1 allows for a smaller width of the insulating region, facilitating alignment. The width of the insulating region is parallel to the aforementioned first direction L1.

[0107] For example, among all the insulating openings, the distance D1 between a first insulating opening 13 and its adjacent second insulating opening 15 is: 1 micron, or 10 microns, or 60 microns, or 100 microns, or 170 microns, or 300 microns, or 480 microns, or 500 microns, or 504 microns, or 650 microns, or 800 microns, or 1000 microns.

[0108] Optionally, as shown in FIG1 , the first conductive regions and the second conductive regions are alternately distributed in the first direction L1. In the first direction L1 where the first and second conductive regions are alternately distributed, the size of the second insulating openings 15 is between 1 micron and 1000 microns. Within this size range in the first direction L1, the second insulating openings 15 provide excellent insulation complement to the first insulating openings 13 and can reduce the width of the insulating regions, facilitating alignment.

[0109] For example, in the first direction L1 in which the first conductive regions and the second conductive regions are alternately distributed, the size of the second insulating opening 15 is: 1 micron, or 10 microns, or 60 microns, or 100 microns, or 170 microns, or 360 microns, or 480 microns, or 500 microns, or 504 microns, or 650 microns, or 800 microns, or 1000 microns.

[0110] Optionally, the distance between adjacent second insulating openings 15 among all insulating openings is between 1 micron and 1000 microns. Within this range, the second insulating openings 15 provide enhanced insulation supplementation, further improving insulation performance. It should be noted that the smaller the distance between adjacent second insulating openings 15, the smaller the width of the insulating region can be, facilitating alignment. The width of the insulating region is parallel to the aforementioned first direction L1.

[0111] For example, among all the insulating openings, the distance between adjacent second insulating openings 15 is: 1 micron, or 10 microns, or 60 microns, or 100 microns, or 170 microns, or 300 microns, or 480 microns, or 500 microns, or 590 microns, or 650 microns, or 800 microns, or 1000 microns.

[0112] Optionally, among all the insulating openings: the number of all the second insulating openings 15 is greater than 1, and the number of types of shapes of the orthographic projections of all the second insulating openings 15 on the surface parallel to the surface of the transparent conductive layer 12 away from the silicon substrate 1 is greater than or equal to 1. That is, among all the insulating openings, the orthographic projections of all the second insulating openings 15 on the surface parallel to the surface of the transparent conductive layer 12 away from the silicon substrate 1 have various shapes, and the shapes of the second insulating openings 15 are flexible and diverse.

[0113] Optionally, the orthographic projection of the second insulating opening 15 on a surface parallel to the surface of the transparent conductive layer 12 away from the silicon substrate 1 is elliptical or square. The second insulating opening 15 of the above shape is easy to obtain and has flexible and diverse shapes.

[0114] Optionally, the doping types of the first transmission layer and the second transmission layer are different, that is, one of them is P-type doped and the other is N-type doped. Referring to Figure 1, all the first insulating openings 13 penetrate the transparent conductive layer 12 on the barrier layer 4 and extend into the second transmission layer on the barrier layer 4, indicating that all the first insulating openings 13 not only penetrate the transparent conductive layer 12 on the barrier layer 4, but also disconnect at least part of the second transmission layer on the barrier layer 4. The deeper the first insulating openings 13 are set, the more layers are disconnected, and the better the insulation effect. Since all the aforementioned insulating openings extend at most to the surface of the barrier layer 4 close to the silicon substrate 1, the first insulating openings 13 also extend at most to the surface of the barrier layer 4 close to the silicon substrate 1. In the back-contact solar cell, a first transmission layer is also provided between the barrier layer 4 and the silicon substrate 1. The first insulating openings 13 do not destroy the first transmission layer between the barrier layer 4 and the silicon substrate 1. The first transmission layer maintains good electrical properties and passivation properties. In summary, the back-contact solar cell of the present application has a better insulation effect and a higher photoelectric conversion efficiency. When the first insulating opening 13 extends to the barrier layer 4, the barrier layer 4 is partially etched to form a groove, which has a better insulation effect. At the same time, since the groove is formed on the surface of the barrier layer 4, the reflectivity of the light is increased, which helps to improve the efficiency of the battery.

[0115] Optionally, all insulating openings penetrate the second transmission layer on the barrier layer 4 and extend into the barrier layer 4. All insulating openings are set deeper, disconnecting not only the transparent conductive layer 12 on the barrier layer 4 but also the second transmission layer on the barrier layer 4. Furthermore, the barrier layer 4 is partially etched to form grooves, which improves the insulation effect. Furthermore, the grooves formed on the surface of the barrier layer 4 increase the reflectivity of light, which helps improve the efficiency of the battery. Furthermore, all insulating openings do not damage the first transmission layer, which maintains good electrical properties and passivation properties.

[0116] Optionally, referring to Figure 1, the first transmission layer includes: a first back passivation layer 2 and a first doping layer 3 arranged in a stacked manner, wherein the first back passivation layer 2 is closer to the silicon substrate 1 than the first doping layer 3. The second transmission layer includes: a second back passivation layer 7 and a second doping layer 8 arranged in a stacked manner, wherein the second back passivation layer 7 is closer to the silicon substrate 1 than the second doping layer 8. The first doping layer 3 and the second doping layer 8 have different doping types, that is, one is an N-type doping layer and the other is a P-type doping layer. Optionally, the materials of the first back passivation layer 2 and the second back passivation layer 7 are both selected from: amorphous silicon, and the materials of the first doping layer 3 and the second doping layer 8 are both selected from: doped amorphous silicon, or doped microcrystalline silicon, that is, the back contact solar cell is an HBC (Heterojunction Back Contact) cell, which has the advantages of high open circuit voltage, low process temperature, and excellent temperature characteristics. Alternatively, optionally, the materials of the first back passivation layer 2 and the second back passivation layer 7 are both selected from silicon oxide, and the materials of the first doping layer 3 and the second doping layer 8 are both selected from doped polycrystalline silicon or doped microcrystalline silicon, that is, the back-contact solar cell is a TBC (Tunnel Oxide Back Contact) cell, which also has the advantages of high open-circuit voltage, low process temperature, and excellent temperature characteristics. Alternatively, optionally, the materials of the first back passivation layer 2 and the second back passivation layer 7 are respectively selected from amorphous silicon or silicon oxide, and the materials of the first doping layer 3 and the second doping layer 8 are respectively selected from doped polycrystalline silicon or doped microcrystalline silicon. That is, the materials of the first back passivation layer 2 and the second back passivation layer 7 are selected from amorphous silicon and silicon oxide respectively, and the materials of the first doping layer 3 and the second doping layer 8 are selected from doped polycrystalline silicon and microcrystalline silicon respectively. The back-contact solar cell is a HTBC (Heterojunction Tunnel Oxide Back Contact) cell, which also has the advantages of high open-circuit voltage, low process temperature, and excellent temperature characteristics.

[0117] Optionally, referring to FIG. 1 , the back-contact solar cell further includes a first electrode 14 located on the transparent conductive layer 12, outside the barrier layer 4 in the first conductive region. A second electrode 16 located on the transparent conductive layer 12, in the second conductive region. Both the first electrode 14 and the second electrode 16 are metal electrodes, and their specific materials are not limited.

[0118] Optionally, referring to FIG. 1 , the silicon substrate 1 has a second surface 222 opposite to the first surface 111 , and the back-contact solar cell further includes: a front passivation layer 9 and a front anti-reflection layer 10 sequentially stacked on the second surface 222 of the silicon substrate 1 .

[0119] The present application also provides a method for preparing a back-contact solar cell, which may include the following steps.

[0120] Step S1, providing a conductive substrate; the conductive substrate includes: a silicon substrate; the silicon substrate has a first surface; the first surface includes: a first conductive region, a second conductive region and an insulating region located between the first conductive region and the second conductive region; a first transmission layer, located on the first conductive region and the insulating region; a blocking layer, located in the insulating region on the first transmission layer; a second transmission layer, located on the blocking layer and the second conductive region; a transparent conductive layer, located on the second transmission layer and the exposed first transmission layer.

[0121] The conductive substrate can refer to the related description of the back contact solar cell mentioned above, and can achieve the same or similar beneficial effects. In order to avoid repetition, it will not be described here. The preparation method of each layer in the conductive substrate is not specifically limited.

[0122] Figures 2 to 25 show schematic diagrams of steps for preparing a back-contact solar cell according to an embodiment of the present application. For example, a conductive substrate in the present application may be as shown in Figure 6 .

[0123] Step S2: forming an insulating opening on the portion of the transparent conductive layer located in the insulating region by using a laser.

[0124] Laser irradiation is used to form the insulating opening, which is a relatively simple and easy method to implement. More specifically, the method for preparing a back-contact solar cell using laser to form the insulating opening is less expensive and has a shorter process time than methods such as mask wetting to form the insulating opening.

[0125] The aforementioned step S2 may include: using a laser including a main light spot to irradiate the portion of the transparent conductive layer located in the insulating area to form at least two insulating openings in the portion of the transparent layer and the second transmission layer located in the insulating area, and the first insulating opening is formed at the position irradiated by the main light spot.

[0126] For example, referring to FIG25 , a laser including a main light spot is used to illuminate the portion of the transparent conductive layer 12 located in the insulating region, i.e., the transparent conductive layer 12 located on the barrier layer 4, so as to form at least two insulating openings in the transparent layer 12 located on the barrier layer 4 and the second transmission layer. That is, at least two insulating openings are formed in the portion of the transparent layer 12 and the second transmission layer located in the insulating region, and the position illuminated by the main light spot forms a first insulating opening 13. The depth, shape, etc. of the insulating opening and the first insulating opening 13 refer to the relevant description of the back-contact solar cell described above, and can achieve the same or similar beneficial effects. To avoid repetition, they will not be described here. It should be noted that the main light spot 2 refers to the light spot that exists during the operation of the laser without special debugging, and the shape of the main light spot 2 is not specifically limited.

[0127] Figure 8 shows a schematic diagram of the first laser in an embodiment of the present application. Figure 9 shows a schematic diagram of the second laser in an embodiment of the present application. Figure 10 shows a schematic diagram of the third laser in an embodiment of the present application. Figure 11 shows a schematic diagram of the fourth laser in an embodiment of the present application. Figure 12 shows a schematic diagram of the fifth laser in an embodiment of the present application. Figure 13 shows a schematic diagram of the sixth laser in an embodiment of the present application. Figure 14 shows a schematic diagram of the seventh laser in an embodiment of the present application. Figure 15 shows a schematic diagram of the eighth laser in an embodiment of the present application. Figure 16 shows a schematic diagram of the movement of the first laser in an embodiment of the present application. Figure 17 shows a schematic diagram of the movement of the second laser in an embodiment of the present application. Figure 18 shows a processing microscope image of a laser forming an insulating opening in an embodiment of the present application.

[0128] Optionally, referring to Figures 8 to 18, in the aforementioned step S2, the main light spot 2 moves along the second direction to illuminate the transparent conductive layer 12 located on the barrier layer 4. Before the aforementioned step S2, the method may further include: adjusting the optical path of the laser so that the aforementioned laser also includes: at least one diffraction spot 21 located on at least one side of the main light spot 2 in a third direction perpendicular to the aforementioned second direction. This step S2 includes: using a laser including the main light spot 2 and the diffraction spot 21 to move along the aforementioned second direction to illuminate the transparent conductive layer 12 located on the barrier layer 4, so as to form at least two insulating openings in the transparent layer 12 located on the barrier layer 4 and the second transmission layer, and the position illuminated by the main light spot 2 forms the first insulating opening 13, and the position illuminated by the diffraction spot 21 forms the second insulating opening 15. By simply adjusting the optical path of the laser, the diffraction spot 21 can be obtained at the same time as the main light spot 2, thereby obtaining the aforementioned first insulating opening 13 and second insulating opening 15, thereby simplifying the process. It should be noted that the illumination area of ​​a main light spot 2 is larger than the illumination area of ​​a diffraction light spot 21 .

[0129] For example, referring to Figures 8, 9, and 18, the main light spot 2 can be moved in the left-right direction to illuminate the transparent conductive layer 12 and the second transmission layer located on the barrier layer 4, and / or can be moved in the up-down direction to illuminate the transparent conductive layer 12 and the second transmission layer located on the barrier layer 4. When the main light spot 2 is moved in the left-right direction to illuminate the transparent conductive layer 12 and the second transmission layer located on the barrier layer 4, the position illuminated by the main light spot 2 forms the first insulating opening 13, and the position illuminated by the diffraction light spot 21 in the up-down direction forms the second insulating opening 15. When the main light spot 2 is moved in the up-down direction to illuminate the transparent conductive layer 12 and the second transmission layer located on the barrier layer 4, the position illuminated by the main light spot 2 forms the first insulating opening 13, and the position illuminated by the diffraction light spot 21 in the left-right direction forms the second insulating opening 15. When the main light spot 2 is moved in both the left-right and up-down directions to illuminate the transparent conductive layer 12, the position illuminated by the main light spot 2 forms the first insulating opening 13, and the positions illuminated by the diffraction light spot 21 in the up-down and left-right directions form the second insulating opening 15.

[0130] For another example, referring to Figures 10, 12, 16, and 17, the main light spot 2 moves in the left and right directions to illuminate the transparent conductive layer 12 and the second transmission layer located on the blocking layer 4. The position where the main light spot 2 illuminates forms a first insulating opening 13, and the position where the diffraction light spot 21 in the up and down directions illuminates forms a second insulating opening 15.

[0131] For another example, referring to Figures 14 and 15, the main light spot 2 moves along the left and right directions to illuminate the transparent conductive layer 12 and the second transmission layer located on the blocking layer 4. The position illuminated by the main light spot 2 forms a first insulating opening 13, and the position illuminated by the diffraction spot 21 above forms a second insulating opening 15.

[0132] For another example, referring to Figures 11 and 13, the main light spot 2 moves in the up and down directions to illuminate the transparent conductive layer 12 and the second transmission layer located on the blocking layer 4. The position where the main light spot 2 illuminates forms a first insulating opening 13, and the position where the diffraction light spot 21 in the left and right directions illuminates forms a second insulating opening 15.

[0133] Optionally, referring to Figures 8, 9, and 18, the diffraction spots 21 are distributed around the main light spot 2, and thus, second insulating openings 15 can be formed on at least both sides of the second direction of movement of the main light spot 2. The second insulating openings 15 on both sides have a comparable insulating supplementary effect on the first insulating opening 13, and the insulation effect is better.

[0134] Optionally, referring to FIG. 16 , adjacent diffraction spots 21 in the second direction are at least tangent to each other, thereby forming a continuous diffraction spot band 22. In this case, the second insulating opening 15 has good continuity and penetration, and the insulation effect is better. When adjacent diffraction spots 21 intersect, the ratio of the area of ​​the intersecting portion to the area of ​​a diffraction spot 21 is not specifically limited.

[0135] Alternatively, referring to FIG. 17 , adjacent diffraction spots 21 are spaced apart in the second direction, resulting in a discontinuous diffraction spot band 22. In this case, the resulting second insulating opening 15 still melts away at least a portion of the transparent conductive layer 12, reducing leakage paths and improving insulation. Furthermore, adjacent diffraction spots 21 do not overlap, further minimizing laser damage to the underlying film layer.

[0136] Optionally, referring to Figures 8 and 9, the distance D2 between the main light spot 2 and its adjacent diffraction light spot 21 is 1 micron to 1000 microns. Within this range, the distance between the second insulating opening 15 and its adjacent first insulating opening 13 is appropriate, and the second insulating opening 15 provides better insulation supplementation for its adjacent first insulating opening 13, further improving insulation performance. It should be noted that the smaller D2 is, the smaller the width of the insulating area can be made, which is conducive to alignment. D2 here can be: the minimum distance between the main light spot 2 and its adjacent diffraction light spot 21.

[0137] For example, the distance D2 between the main light spot 2 and its adjacent diffraction spot 21 is: 1 micron, or 10 microns, or 60 microns, or 100 microns, or 170 microns, or 300 microns, or 480 microns, or 500 microns, or 504 microns, or 650 microns, or 800 microns, or 1000 microns.

[0138] Optionally, in a third direction perpendicular to the second direction in which the main light spot 2 moves, the size of the diffraction spot 21 is 1 micron to 1000 microns. The size of the second insulating opening 15 thus formed is more appropriate, and the insulation supplement effect for the first insulating opening 13 is better.

[0139] For example, in the third direction perpendicular to the second direction in which the main light spot 2 moves, the size of the diffraction spot 21 is: 1 micron, or 70 microns, or 90 microns, or 100 microns, or 170 microns, or 300 microns, or 480 microns, or 500 microns, or 504 microns, or 650 microns, or 800 microns, or 1000 microns.

[0140] Optionally, referring to Figure 17, in the aforementioned second direction, adjacent diffraction spots 21 are spaced apart, and the distance D3 between adjacent diffraction spots 21 is: 1 micron to 1000 microns. The size of the second insulating opening 15 formed thereby is more appropriate, and the insulation supplement effect on the first insulating opening 13 is better.

[0141] For example, in the aforementioned second direction, adjacent diffraction spots 21 are spaced apart, and the distance D3 between adjacent diffraction spots 21 is: 1 micron, or 70 microns, or 90 microns, or 100 microns, or 170 microns, or 300 microns, or 480 microns, or 500 microns, or 504 microns, or 600 microns, or 800 microns, or 1000 microns.

[0142] Optionally, the number of all diffraction spots 21 is greater than 1, the types of shapes of all diffraction spots 21 are greater than or equal to 1, the shapes of the diffraction spots 21 are diverse, and the shapes of the obtained second insulating openings 15 are flexible and diverse.

[0143] Optionally, referring to FIG8 , the shape of the diffraction spot 21 is an ellipse, or referring to FIG9 , the shape of the diffraction spot 21 is a square. The diffraction spots 21 of the above shapes are easy to obtain and have flexible and diverse shapes.

[0144] Optionally, in the aforementioned step S2, the laser is at least one of an infrared laser, a green laser, and an ultraviolet laser, and the above lasers are easy to obtain and have low cost.

[0145] Optionally, in the aforementioned step S2, the wavelength of the laser is at least one of 355 nm, 532 nm, and 1064 nm, and the above lasers are easy to obtain and have low cost.

[0146] And / or, optionally, in the aforementioned step S2, the pulse width of the laser is 50 ps (picoseconds) to 100 ns (nanoseconds), so that the size of the second insulating opening 15 formed thereby is more appropriate, and the insulation supplement effect of the first insulating opening 13 is more significant. For example, the pulse width of the laser is 50 ps, ​​or 90 ps, ​​or 680 ps, ​​or 990 ps, ​​or 1 ns, or 12 ns, or 23 ns, or 40 ns, or 50 ns, or 72 ns, or 91 ns, or 100 ns.

[0147] And / or, optionally, in step S2, the laser energy is 0.1W to 50W, thereby forming a suitable depth of the first insulating opening 13 and a suitable size of the second insulating opening 15, thereby achieving a good insulation effect. For example, the laser energy is 0.1W, 0.8W, 1W, 8.2W, 10W, 16W, 25W, 26W, 40W, or 50W.

[0148] The present application also provides a photovoltaic module comprising: a plurality of any of the aforementioned back-contact solar cells, with no specific limitation on whether the photovoltaic module includes other structures. For example, the photovoltaic module may further include: a front encapsulating film and a cover sheet positioned sequentially on the light-facing side of the back-contact solar cells, and a rear encapsulating film and a back sheet positioned sequentially on the back-light-opposed side of the back-contact solar cells.

[0149] It should be noted that the preparation method of the back-contact solar cell, the photovoltaic module, and the back-contact solar cell can be referenced to each other and have the same or similar beneficial effects as any of the aforementioned back-contact solar cells. In order to avoid repetition, they will not be repeated here.

[0150] The present application is further explained below with reference to specific embodiments.

[0151] Example 1

[0152] 2, on the first surface 111 of the silicon substrate 1, PECVD (Plasma Enhanced Chemical Vapor Deposition) is used to sequentially deposit the first back passivation layer 2, the first doping layer 3, the barrier layer 4, and the mask layer 5. The material of the first back passivation layer 2 is intrinsic amorphous silicon. The thickness of the first back passivation layer 2 is 1nm (nanometer) to 50nm, the thickness of the first doping layer 3 is 3nm-50nm, and the thickness of the barrier layer 4 is 10nm-1000nm. The material of the mask layer 5 is intrinsic amorphous silicon, and its thickness is 3nm-500nm. The first doping layer 3 is an N-type amorphous silicon layer, and the barrier layer 4 can use SiN x (Silicon Nitride) or SiO x (Silicon oxide) layer. X in the chemical formula only needs to be greater than 0.

[0153] As shown in FIG3 , a portion of the barrier layer 4 and the underlying back first passivation layer 2 and first doping layer 3 are removed according to a pattern using a laser or mask plus wet etching to form a first opening 6 with a pattern.

[0154] As shown in Figure 4, PECVD is used to sequentially deposit the back second passivation layer 7 and the second doping layer 8 on the first side of the silicon substrate 1. The material of the back second passivation layer 7 is intrinsic amorphous silicon. The thickness of the back second passivation layer 7 is 1nm-50nm. The thickness of the second doping layer 8 is 3nm-50nm. PECVD is used to sequentially deposit the front passivation layer 9 and the front anti-reflection layer 10 on the second surface 222 of the silicon substrate 1. The material of the front passivation layer 9 is intrinsic amorphous silicon. The thickness of the front passivation layer 9 is 1nm-50nm. The thickness of the front anti-reflection layer 10 is 10nm-500nm. The second doping layer 8 can be a P-type amorphous silicon layer, and the front anti-reflection layer 10 can be SiN xor SiO x layer.

[0155] 5 , a portion of the barrier layer 4, the back second passivation layer 7, and the second doping layer 8 on the first doping layer 3 are removed in a patterned manner. For example, laser removal or wet etching can be used to form the second opening 11.

[0156] As shown in FIG6 , a transparent conductive layer 12 is deposited on the first side by PVD (Physical Vapor Deposition), and the thickness of the transparent conductive layer 12 is 10 nm (nanometers) to 500 nm.

[0157] As shown in FIG7 , a laser beam comprising a main spot 2 and a diffraction spot 21 surrounding the main spot 2 is used to illuminate the transparent conductive layer 12 and the second transmission layer located on the barrier layer 4. The locations illuminated by the main spot 2 form the first insulating opening 13, while the locations illuminated by the diffraction spot 21 form the second insulating opening 15. In this step, the laser beam used has a wavelength of 355 nm, a pulse width of 50 ns, and a laser energy of 20 W. Adjacent diffraction spots 21 overlap by 15% in area, and the diffraction spots 21 are elliptical in shape. The first insulating opening 13 and two second insulating openings 15 located on either side of the first insulating opening 13 along the extension direction of the first electrode 14 are formed. The first insulating opening 13 and all second insulating openings 15 penetrate the transparent conductive layer 12 on the barrier layer 4, the second doped layer 8 in the second transmission layer, and the back second passivation layer 7. Neither the first insulating opening 13 nor the second insulating opening 15 enters the first transmission layer. Simultaneously, the back contact solar cell is free of material from the melted transparent conductive layer 12, the second doped layer 8, and the back second passivation layer 7. Adjacent diffraction spots 21 having a 15% overlap in area specifically means that the area of ​​the overlapping portion of two adjacent diffraction spots 21 accounts for 15% of the area of ​​a single diffraction spot 21.

[0158] As shown in FIG1 , a conductive silver paste is printed on the transparent conductive layer 12 and cured to form a first electrode 14 and a second electrode 16 . The preparation method of the electrodes is not specifically limited.

[0159] The back contact solar cell prepared in Example 1 has an HBC structure.

[0160] Example 2

[0161] The difference from Example 1 is the difference in battery type. The materials of the first back passivation layer 2 and the second back passivation layer 7 are both SiO x The materials of the first doping layer 3 and the second doping layer 8 are both doped polysilicon. The back contact solar cell formed in Example 2 has a TBC structure. The rest of Example 2 is the same as Example 1.

[0162] Comparative Example

[0163] The difference from Example 1 is that the steps prior to and including Figure 6 are the same, except that the laser insulation spot is different and does not have a diffraction spot. All other conditions are the same. In the back-contact solar cell formed in the comparative example, the transparent conductive layer 12 and the second transmission layer located on the barrier layer 4 have only one insulating opening, the first insulating opening, and no second insulating opening.

[0164] Performance tests were performed on 1000 back-contact solar cells formed in Example 1 and 1000 back-contact solar cells formed in the comparative example under the same test conditions. The test results are shown in Table 1 below.

[0165] Table 1: Performance comparison of back contact solar cells formed in Example 1 and comparative example

[0166] In Table 1, the various data of Example 1 are the results of arithmetic averaging of the test results of 1000 back-contact solar cells corresponding to Example 1, and the various data of the comparative example are the results of arithmetic averaging of the test results of 1000 back-contact solar cells corresponding to the comparative example. In Table 1, Jsc represents the short-circuit current density of the back-contact solar cell, and Voc represents the open-circuit voltage of the back-contact solar cell. FF represents the fill factor of the back-contact solar cell, Eff represents the photoelectric conversion efficiency of the back-contact solar cell, Rs represents the series resistance of the back-contact solar cell, Rsh_D represents the parallel resistance of the back-contact solar cell, and IVRV2 represents the reverse current of the back-contact solar cell. It can be concluded from Table 1 above that, compared with the comparative example, the parallel resistance of Example 1 is large, and the reverse current is small. Therefore, the insulation resistance value of Example 1 is large, and the insulation effect is better. The main reason is that in Example 1, due to the presence of the diffraction spot 21, the laser forms a larger number of insulating openings, that is, in addition to the first insulating opening 13, a second insulating opening 15 is also formed. The second insulating opening 15 plays a good complementary role to the insulating effect of the first insulating opening 13, thereby improving the insulation effect.

[0167] Referring to Figure 19, the inventors found that the shape of the insulating opening is relatively regular, resulting in weak reflection on the backlight surface of the back-contact solar cell. There are basically no reflective components in the insulating opening, resulting in weak reflection in the insulating opening. To address this problem, in this application, referring to Figures 20, 21, 22, and 23, both sides of the insulating opening are provided with reflective components 17 in the insulating area, and the intersection profile 171 at the intersection of the reflective component 17 and the insulating opening has a portion 1711 extending into the insulating opening. Referring to Figure 24, furthermore, the reflective component 17 and the portion 1711 of the reflective component 17 extending into the insulating opening provide a larger reflective surface, thereby improving the light reflection of the backlight surface of the back-contact solar cell, improving the utilization rate of sunlight, and thereby improving the photoelectric conversion efficiency of the back-contact solar cell. In Figure 24, the dotted arrows are schematic diagrams of light. The upward dotted arrow is the light that passes through the silicon substrate 1 and is received by the portion 1711 of the reflective component 17 that extends into the insulating opening. The downward dotted arrow is a schematic diagram of the reflected light that re-enters the interior of the back-contact solar cell after reflection. The two sides of the insulating opening here can be opposite sides in one direction of the insulating opening, and this direction is not limited. For example, referring to Figures 20, 21, 22, and 23, within the insulating region, the insulating opening has reflective components 17 on both sides in the first direction L1 along which the first conductive region and the second conductive region are distributed.

[0168] It should be noted that the reflective member 17 and the portion 1711 of the reflective member 17 extending into the insulating opening specifically comprise the portion of the existing structure within the insulating region of the back-contact solar cell after the insulating opening is formed, excluding the insulating opening. The specific composition of the reflective member 17 is determined by, for example, the depth of the insulating opening.

[0169] Optionally, referring to Figure 25, the transparent conductive layer 12 has a first flange 121 near the insulating opening. The first flange 121 is folded in the direction away from the insulating opening. Referring to Figure 26, the first flange 121 can be clearly seen in the scanning electron microscope image of the insulating opening of the back contact solar cell. Referring to Figure 27, the light received by the first flange 121 after passing through the silicon substrate 1 will be reflected, and the reflected light re-enters the interior of the back contact solar cell. Then, the first flange 121 provides a larger reflective surface, which improves the light reflection of the backlight surface of the back contact solar cell, improves the utilization rate of sunlight, and thus improves the photoelectric conversion efficiency of the back contact solar cell. The dotted line with an arrow in Figure 27 is a schematic diagram of light. The main component of the first flange 121 is the transparent conductive layer. The first flange 121 can also contain components of other layers at the insulating opening, which is not specifically limited.

[0170] Optionally, referring to FIG28 , the intersection profile 171 of the reflective component 17 and the insulating opening includes a second flange 1713. Light passing through the silicon substrate 1 is received by the second flange 1713 and then reflected, with the reflected light re-entering the interior of the back-contact solar cell. Consequently, the second flange 1713 provides a larger reflective surface, improving light reflection from the backlight surface of the back-contact solar cell, increasing the utilization of sunlight, and thereby improving the photoelectric conversion efficiency of the back-contact solar cell. It should be noted that the shape of the second flange 1713 is not specifically limited. For example, the shape of the second flange 1713 is similar to that of the first flange 121. Specifically, the second flange 1713 comprises the portion of the existing structure within the insulating region of the back-contact solar cell after the insulating opening is formed, excluding the insulating opening. Its specific composition is determined by, among other factors, the depth of the insulating opening. From the electron microscope image shown in FIG28 , it is clearly visible that the reflective component 17 and the intersection profile of the reflective component 17 and the insulating opening have a portion 1711 extending into the insulating opening. At the same time, the intersection profile has a second flange 1713. It should be noted that the second flange 1713 can be a burr on the intersection profile, etc., and the size of the second flange 1713 is usually small.

[0171] Optionally, referring to Figures 20, 21, 22, and 23, the intersection contour 171 of the reflective component 17 at the intersection with the insulating opening is composed of several intersecting sub-contours, with the intersection of adjacent sub-contours being at 1712. Referring to Figure 21, the reflective component 17 further comprises an extended edge 172 located within the insulating opening, continuous with the intersection 1712, and extending into the interior of the insulating opening. Light received by the extended edge 172 that passes through the silicon substrate 1 is reflected, and the reflected light re-enters the interior of the back-contact solar cell. Consequently, the extended edge 172 provides a larger reflective surface, improving light reflection from the backlight surface of the back-contact solar cell, increasing the utilization of sunlight, and thereby improving the photoelectric conversion efficiency of the back-contact solar cell. It should be noted that the shape of the extended edge 172 is not specifically limited. Specifically, the extended edge 172 is the portion of the existing structure within the insulating region of the back-contact solar cell after the insulating opening is formed, excluding the insulating opening. Its specific composition is determined by, among other factors, the depth of the insulating opening. From the electron microscope image shown in FIG. 28 , the extended edge 172 can be clearly seen.

[0172] Optionally, the reflective component 17 is located in the insulating opening, is continuous with the intersection 1712, and may also have a third flange on the extended edge 172 that continues to extend into the insulating opening. The third flange reflects the light that passes through the silicon substrate 1, and the reflected light re-enters the interior of the back-contact solar cell. Thus, the third flange provides a larger reflective surface, thereby improving the light reflection of the backlight surface of the back-contact solar cell, improving the utilization rate of sunlight, and thus improving the photoelectric conversion efficiency of the back-contact solar cell. It should be noted that the shape of the third flange is not specifically limited. The third flange is specifically: after the insulating opening is formed, the existing structure located in the insulating area of ​​the back-contact solar cell, excluding the insulating opening. Its specific composition is determined by the depth of the insulating opening, etc.

[0173] Optionally, referring to Figures 20, 21, and 22, the maximum distance D4 between the intersection points 1712 of adjacent sub-contours and the adjacent intersection contour 171 in the first direction L1 in which the first conductive area and the second conductive area are distributed is less than half of the maximum width D5 of the insulating opening. The two intersection points 1712 relatively distributed in the first direction L1 basically do not overlap, thereby having a better insulation effect.

[0174] Optionally, the shape of the intersection profile 171 is an arc shape or a straight edge shape, and the shape of the intersection profile 171 is flexible and diverse.

[0175] Optionally, referring to FIG. 19 , a first transmission layer and a second transmission layer are alternately disposed on a silicon substrate 1. A barrier layer 4 is located on the end region of the first transmission layer proximal to the second transmission layer. The second transmission layer also has an isolated island portion covering the barrier layer 4. A transparent conductive layer 12 covers the portion of the first transmission layer not covered by the barrier layer 4, as well as the second transmission layer. The insulating opening penetrates the transparent conductive layer 12 and extends into the isolated island portion of the second transmission layer. This indicates that, along the thickness direction of the silicon substrate 1, the insulating opening not only penetrates the transparent conductive layer 12 but also disconnects at least a portion of the isolated island portion of the second transmission layer. The deeper the insulating opening is, the more layers are disconnected, resulting in a better insulation effect. The insulating opening extends at most to the surface of the barrier layer 4 proximal to the silicon substrate 1. In a back-contact solar cell, a first transmission layer is disposed between the barrier layer 4 and the silicon substrate 1. The insulating opening extends at most to the surface of the barrier layer 4 proximal to the silicon substrate 1. In other words, the insulating opening does not damage the first transmission layer between the barrier layer 4 and the silicon substrate 1, allowing the first transmission layer to maintain good electrical and passivation properties. In summary, the back-contact solar cell of the present application has better insulation effect and higher photoelectric conversion efficiency.

[0176] Optionally, the insulating opening penetrates the isolated island portion of the second transmission layer and extends into the barrier layer 4. The insulating opening is set deeper along the thickness direction of the silicon substrate 1, disconnecting not only the transparent conductive layer 12 but also the isolated island portion of the second transmission layer. As shown in FIG19 , the insulating opening also disconnects the second doped layer 8 and the back second passivation layer 7 in the isolated island portion, and also partially disconnects the barrier layer 4, thereby achieving a better insulation effect. Furthermore, the insulating opening does not damage the first transmission layer, which maintains good electrical and passivation properties.

[0177] Optionally, referring to Figure 23, the insulating opening is formed by laser melting at least a portion of the transparent conductive layer 12 and at least a portion of the isolated island portion. The back contact solar cell also includes: a mixed layer 18 formed by a laser-melted substance. The mixed layer 18 is located on the barrier layer 4, and the insulating opening penetrates the mixed layer 18 and extends into the barrier layer 4. Along the thickness direction of the silicon substrate 1, the insulating opening is set deeper, which not only disconnects the transparent conductive layer 12, but also disconnects the mixed layer 18 and part of the barrier layer 4, resulting in a better insulation effect. Moreover, the insulating opening does not destroy the first transmission layer, and the first transmission layer maintains good electrical properties and passivation properties. The mixed layer 18 formed by the laser-melted substance has poor conductivity, so the adjacent sub-contours forming the intersection contour 171 can be tangent, and the form of the intersection contour 171 is flexible and diverse. It should be noted that the mixed layer 18 formed by the laser-melted substance has poor conductivity, so even if it is tangent, the back contact solar cell can still maintain good insulation performance. Here, the back contact solar cell further includes: a mixed layer 18 formed by a laser-melted material. That is, the laser power is relatively low, which can reduce laser damage to the film layer below the insulating opening.

[0178] Optionally, referring to FIG. 19 , the first transmission layer includes: a stacked back first passivation layer 2 and a first doped layer 3, with the back first passivation layer 2 being closer to the silicon substrate 1 than the first doped layer 3. The second transmission layer includes: a stacked back second passivation layer 7 and a second doped layer 8, with the back second passivation layer 7 being closer to the silicon substrate 1 than the second doped layer 8. The first doped layer 3 and the second doped layer 8 have different doping types, i.e., one is an N-type doped layer and the other is a P-type doped layer. Optionally, the insulating opening penetrates the second doped layer 8 in the isolated island portion of the second transmission layer and extends into the back second passivation layer 7 in the isolated island portion of the second transmission layer. The deeper the insulating opening is along the thickness direction of the silicon substrate 1, disconnecting not only the transparent conductive layer 12 but also the second doped layer 8 of the second transmission layer and a portion of the back second passivation layer 7, thereby achieving better insulation. Furthermore, the insulating opening does not damage the first transmission layer, which maintains good electrical and passivation properties.

[0179] Optionally, the materials of the first back passivation layer 2 and the second back passivation layer 7 are both selected from: amorphous silicon, and the materials of the first doping layer 3 and the second doping layer 8 are both selected from: doped amorphous silicon, or doped microcrystalline silicon, that is, the back contact solar cell is an HBC (Heterojunction back contact) cell, which has the advantages of high open circuit voltage, low process temperature, excellent temperature characteristics, etc.

[0180] Or, optionally, the materials of the first back passivation layer 2 and the second back passivation layer 7 are both selected from: silicon oxide, and the materials of the first doping layer 3 and the second doping layer 8 are both selected from: doped polycrystalline silicon, or, doped microcrystalline silicon, that is, the back contact solar cell is a TBC (Tunnel Oxide Passivated Contactbackcontact) cell, and the back contact solar cell also has the advantages of high open circuit voltage, low process temperature, excellent temperature characteristics, etc.

[0181] Optionally, referring to FIG. 19 , the back-contact solar cell further includes a first electrode 14 and a second electrode 16 located on the first side of the silicon substrate. The first electrode 14 is located on the transparent conductive layer 12 at a position corresponding to the first transmission layer, and the second electrode 16 is located on the transparent conductive layer 12 at a position corresponding to the second transmission layer. Both the first electrode 14 and the second electrode 16 are metal electrodes, and their specific materials are not limited.

[0182] Optionally, referring to Figure 19 , the back-contact solar cell further includes: a front passivation layer 9 and a front anti-reflection layer 10 sequentially stacked on the second surface 222 of the second side of the silicon substrate 1. The first side and the second side are arranged oppositely.

[0183] The present application also provides a method for preparing a back-contact solar cell, which may include the following steps.

[0184] Step S1, providing a conductive substrate; the conductive substrate includes: a silicon substrate; the silicon substrate has a first surface; the first surface includes: a first conductive region, a second conductive region and an insulating region located between the first conductive region and the second conductive region; a first transmission layer, located on the first conductive region and the insulating region; a blocking layer, located in the insulating region on the first transmission layer; a second transmission layer, located on the blocking layer and the second conductive region; a transparent conductive layer, located on the second transmission layer and the exposed first transmission layer.

[0185] The conductive substrate can refer to the related description of the back contact solar cell mentioned above, and can achieve the same or similar beneficial effects. In order to avoid repetition, it will not be described here. The preparation method of each layer in the conductive substrate is not specifically limited.

[0186] Figures 2 to 6 and Figure 29 show schematic diagrams of the steps for preparing another back-contact solar cell in an embodiment of the present application. For example, a conductive substrate in the present application may be as shown in Figure 6 .

[0187] Step S2: forming an insulating opening on the portion of the transparent conductive layer located in the insulating region by using a laser.

[0188] For example, referring to FIG29 , an insulating opening is formed on the transparent conductive layer 12 using a laser. The opening depth, shape, etc. of the insulating opening refer to the related records of the aforementioned back-contact solar cell, and can achieve the same or similar beneficial effects. In order to avoid repetition, they will not be described here.

[0189] The method for preparing the back-contact solar cell uses a laser to form an insulating opening, which has lower costs and shorter process time than forming the insulating opening by a mask wetting method or other methods.

[0190] Optionally, in the aforementioned step S2, the laser is at least one of an infrared laser, a green laser, and an ultraviolet laser. The above lasers are easy to obtain and have low cost.

[0191] Optionally, in step S2, adjacent laser beams are at least tangent to each other, and the laser beams are shaped like a circle. These laser conditions make it easier to obtain the aforementioned reflective component 17, and in particular, to obtain a portion 1711 extending into the insulating opening within the intersection outline 171 between the reflective component 17 and the insulating opening. For example, adjacent laser beams are tangent to or partially overlap, and the laser beams are shaped like an ellipse or a circle.

[0192] Optionally, in the aforementioned step S2, the wavelength of the laser is at least one of 355 nm, 532 nm, and 1064 nm, and the above lasers are easy to obtain and have low cost.

[0193] And / or, optionally, in the aforementioned step S2, the pulse width of the laser is 50 ps (picoseconds) to 100 ns, so that the size of the groove 1 formed thereby is suitable, and the light reflection from the backlight surface is more significant. For example, the pulse width of the laser is 50 ps, ​​or 90 ps, ​​or 680 ps, ​​or 990 ps, ​​or 1 ns, or 12 ns, or 23 ns, or 40 ns, or 50 ns, or 72 ns, or 91 ns, or 100 ns.

[0194] And / or, optionally, in step S2, the laser energy is 0.1W to 50W, thereby forming an appropriate depth of the insulating opening, a suitable size of the groove 1, etc., and significantly reflecting light from the backlight surface. For example, the laser energy is 0.1W, 0.8W, 1W, 8.2W, 10W, 16W, 25W, 26W, 40W, or 50W.

[0195] The present application also provides a photovoltaic module comprising: a plurality of any of the aforementioned back-contact solar cells, with no specific limitation on whether the photovoltaic module includes other structures. For example, the photovoltaic module may further include: a front encapsulating film and a cover sheet positioned sequentially on the light-facing side of the back-contact solar cells, and a rear encapsulating film and a back sheet positioned sequentially on the back-light-opposed side of the back-contact solar cells.

[0196] It should be noted that the preparation method of the back-contact solar cell, the photovoltaic module, and the back-contact solar cell can be referenced to each other and have the same or similar beneficial effects as any of the aforementioned back-contact solar cells. In order to avoid repetition, they will not be repeated here.

[0197] The present application is further explained below with reference to specific embodiments.

[0198] Example 3

[0199] 2, on the first surface 111 of the silicon substrate 1, PECVD (Plasma Enhanced Chemical Vapor Deposition) is used to sequentially deposit the first back passivation layer 2, the first doping layer 3, the barrier layer 4, and the mask layer 5. The material of the first back passivation layer 2 is intrinsic amorphous silicon. The thickness of the first back passivation layer 2 is 1nm (nanometer) to 50nm, the thickness of the first doping layer 3 is 3nm-50nm, and the thickness of the barrier layer 4 is 10nm-1000nm. The material of the mask layer 5 is intrinsic amorphous silicon, and its thickness is 3nm-500nm. The first doping layer 3 is an N-type amorphous silicon layer, and the barrier layer 4 can use SiN x (Silicon Nitride) or SiO x (Silicon oxide) layer. X in the chemical formula only needs to be greater than 0.

[0200] As shown in FIG3 , a portion of the barrier layer 4 and the underlying back first passivation layer 2 and first doping layer 3 are removed according to a pattern using a laser or mask plus wet etching to form a first opening 6 with a pattern.

[0201] As shown in Figure 4, PECVD is used to sequentially deposit the back second passivation layer 7 and the second doping layer 8 on the first side of the silicon substrate 1. The material of the back second passivation layer 7 is intrinsic amorphous silicon. The thickness of the back second passivation layer 7 is 1nm-50nm. The thickness of the second doping layer 8 is 3nm-50nm. PECVD is used to sequentially deposit the front passivation layer 9 and the front anti-reflection layer 10 on the second surface 222 of the silicon substrate 1. The material of the front passivation layer 9 is intrinsic amorphous silicon. The thickness of the front passivation layer 9 is 1nm-50nm. The thickness of the front anti-reflection layer 10 is 10nm-500nm. The second doping layer 8 can be a P-type amorphous silicon layer, and the front anti-reflection layer 10 can be SiN x or SiO x layer.

[0202] 5 , a portion of the barrier layer 4, the back second passivation layer 7, and the second doping layer 8 on the first doping layer 3 are removed in a patterned manner. For example, laser removal or wet etching can be used to form the second opening 11.

[0203] As shown in FIG6 , a transparent conductive layer 12 is deposited on the first side by PVD (Physical Vapor Deposition), and the thickness of the transparent conductive layer 12 is 10 nm-500 nm.

[0204] As shown in Figure 29, a laser is used to pattern-remove the transparent conductive layer 12 on top of the barrier layer 4, forming an insulating opening. In this step, the laser used has a wavelength of 355 nm, a pulse width of 50 ns, and a laser energy of 20 W. Adjacent laser spots overlap by 17% in area, and the laser beam is circular in shape. The resulting insulating opening penetrates the transparent conductive layer 12, the second doped layer 8 in the isolated island portion of the second transmission layer, and the back second passivation layer 7, extending into the barrier layer 4. The insulating opening does not enter the first transmission layer. Simultaneously, the back contact solar cell is free of the melted transparent conductive layer 12, the second doped layer 8, and the back second passivation layer 7. In a first direction along the first and second conductive regions, within the insulating region, reflective features 17 are located on both sides of the insulating opening. The intersection profile 171 of the reflective feature 17 with the insulating opening includes a portion 1711 extending into the insulating opening. The transparent conductive layer 12, located near the insulating opening, has a first flange 121, and a second flange is located on the intersection profile 171. The reflective component 17 also has an extended edge 172 located in the insulating opening, continuous with the intersection 1712, and extending into the interior of the insulating opening, and the extended edge 172 also has a third flange. The insulating opening of the back-contact solar cell was scanned by an electron microscope, and the resulting scanning electron microscope images are shown in Figures 26 and 28. From the electron microscope image shown in Figure 26, the above-mentioned first flange 121 can be clearly seen. From the electron microscope image shown in Figure 28, the reflective component 17, as well as the portion 1711 extending into the insulating opening, the second flange 1713, and the extended edge 172 of the reflective component 17 can be clearly seen. Adjacent laser spots have an overlap of 17% of the area, which specifically means that the surface area of ​​the overlapping portion of two adjacent spots accounts for 17% of the surface area of ​​one spot.

[0205] As shown in FIG19 , a conductive silver paste is printed on the transparent conductive layer 12 and cured to form a first electrode 14 and a second electrode 16 . The preparation method of the electrodes is not specifically limited.

[0206] The back contact solar cell prepared in Example 3 has an HBC structure.

[0207] Example 4

[0208] The difference from Example 3 is the difference in battery type. The materials of the first back passivation layer 2 and the second back passivation layer 7 are both SiO x The materials of the first doping layer 3 and the second doping layer 8 are both doped polysilicon. The back contact solar cell formed in Example 4 has a TBC structure. The rest of Example 4 is the same as Example 3.

[0209] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0210] It should be noted that, for the sake of simplicity, the method embodiments are described as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present application are not limited by the order of the actions described, because according to the embodiments of the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present application.

[0211] References herein to "one embodiment," "an embodiment," or "one or more embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Furthermore, please note that instances of the phrase "in one embodiment" do not necessarily all refer to the same embodiment.

[0212] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0213] In the claims, any reference signs placed between brackets shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present application may be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.

[0214] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A back contact solar cell, wherein: include: Silicon substrate; The silicon substrate has a first surface; The first surface includes: a first conductive region, a second conductive region, and an insulating region located between the first conductive region and the second conductive region; A first transmission layer, located on the first conductive area and the insulating area; a barrier layer, located in the insulating region on the first transmission layer; a second transmission layer, located on the barrier layer and the second conductive region; A transparent conductive layer, located on the second transmission layer and the exposed first transmission layer; An insulating opening is formed in a portion of the transparent conductive layer located in the insulating region; the insulating opening electrically isolates the first transmission layer from the second transmission layer.

2. The back contact solar cell according to claim 1, wherein: At least two insulating openings are formed in the transparent conductive layer and the portion of the second transmission layer located in the insulating region; the insulating openings extend from the transparent conductive layer to the silicon substrate and at most extend to the surface of the barrier layer close to the silicon substrate; The insulating openings include at least one first insulating opening, and at least the first insulating opening electrically isolates the first transmission layer from the second transmission layer.

3. The back contact solar cell according to claim 2, wherein: The insulating opening further includes at least one second insulating opening, the depth of the second insulating opening is less than or equal to the depth of the first insulating opening, and the second insulating opening is closer to the edge of the blocking layer than the first insulating opening.

4. The back contact solar cell according to claim 3, wherein: It also includes: a first electrode, located on the transparent conductive layer, in the first conductive region; Along the extension direction of the first electrode, in the insulating openings, each of the second insulating openings is symmetrically distributed on both sides of the first insulating opening.

5. The back contact solar cell according to claim 3, wherein: In the insulating openings, the second insulating openings are all distributed on one side of the first insulating opening.

6. The back-contact solar cell according to any one of claims 2 to 5, wherein: All of the first insulating openings penetrate the second transmission layer on the barrier layer and extend into the barrier layer.

7. The back contact solar cell according to any one of claims 1 to 5, wherein: The insulating openings all penetrate the second transmission layer on the barrier layer and extend into the barrier layer.

8. The back contact solar cell according to claim 1, wherein: In the insulating region, both sides of the insulating opening are provided with reflective components; and the intersection contour of the reflective component and the insulating opening at the intersection has a portion extending into the insulating opening.

9. The back contact solar cell according to claim 8, wherein: The transparent conductive layer has a first flange near the insulating opening; the first flange is folded in a direction away from the insulating opening.

10. The back contact solar cell according to claim 8, wherein: The intersection profile has a second flange.

11. The back contact solar cell according to claim 8, wherein: The intersection contour is composed of a plurality of intersecting sub-contours, and the reflective component further comprises an extended edge which is located in the insulating opening, continuous with the intersection points of adjacent sub-contours, and continues to extend into the insulating opening.

12. The back contact solar cell according to claim 11, wherein: The extended edge is provided with a third flange.

13. The back contact solar cell according to claim 11, wherein: The first conductive area and the second conductive area are alternately distributed in the first direction; the maximum distance between the intersection point and the adjacent intersection contour in the first direction is less than half of the maximum width of the insulating opening; the direction of the width is parallel to the first direction.

14. The back-contact solar cell according to any one of claims 8 to 13, wherein: The first transmission layer and the second transmission layer are alternately arranged on the silicon substrate; the barrier layer is located on the end area of ​​the first transmission layer close to the second transmission layer; the second transmission layer also has an island portion covering the barrier layer; the insulating opening penetrates the island portion and extends into the barrier layer.

15. The back contact solar cell according to claim 14, wherein: The insulating opening is formed by laser melting at least a portion of the transparent conductive layer and at least a portion of the isolated island portion; The back contact solar cell further comprises: a mixed layer formed by a laser-melted substance; The mixed layer is located on the barrier layer, the insulating opening penetrates the mixed layer and extends into the barrier layer; the intersection contour is composed of a plurality of intersecting sub-contours, and adjacent sub-contours are tangent to each other.

16. The back-contact solar cell according to any one of claims 1 to 5 and 8 to 13, wherein: The first transmission layer comprises: a back first passivation layer and a first doping layer arranged in a stacked manner; the back first passivation layer is closer to the silicon substrate than the first doping layer; the second transmission layer comprises: a back second passivation layer and a second doping layer arranged in a stacked manner; the back second passivation layer is closer to the silicon substrate than the second doping layer; the first doping layer and the second doping layer have different doping types; The materials of the first back passivation layer and the second back passivation layer are both selected from: amorphous silicon; the materials of the first doping layer and the second doping layer are both selected from doped amorphous silicon or doped microcrystalline silicon; Or, the materials of the first back passivation layer and the second back passivation layer are both selected from: silicon oxide; the materials of the first doping layer and the second doping layer are both selected from doped polycrystalline silicon or doped microcrystalline silicon; Alternatively, the materials of the first back passivation layer and the second back passivation layer are respectively selected from amorphous silicon or silicon oxide, and the materials of the first doping layer and the second doping layer are respectively selected from doped polysilicon or doped microcrystalline silicon.

17. A method for preparing a back-contact solar cell according to any one of claims 1 to 16, wherein: include: Step S1, providing a conductive substrate; The conductive substrate comprises: a silicon substrate; the silicon substrate has a first surface; the first surface comprises: a first conductive region, a second conductive region and an insulating region between the first conductive region and the second conductive region; a first transmission layer, located on the first conductive region and the insulating region; a blocking layer, located in the insulating region on the first transmission layer; a second transmission layer, located on the blocking layer and the second conductive region; a transparent conductive layer, located on the second transmission layer and the exposed first transmission layer; Step S2, forming an insulating opening on the portion of the transparent conductive layer located in the insulating area by using a laser.

18. The method for preparing a back contact solar cell according to claim 17, wherein: Step S2 includes: A laser including a main light spot is used to irradiate the portion of the transparent conductive layer located in the insulating area to form at least two insulating openings in the transparent layer and the second transmission layer located in the insulating area, and the first insulating opening is formed at the position irradiated by the main light spot.

19. The method for preparing a back contact solar cell according to claim 18, wherein: The main light spot moves along the second direction to illuminate the portion of the transparent conductive layer located in the insulating region. Before step S2, the method further includes: adjusting the optical path of the laser so that the laser further includes: at least one diffraction light spot located on at least one side of the main light spot in a third direction perpendicular to the second direction; step S2 includes: A laser including the main light spot and the diffraction light spot is used to move and irradiate along the second direction, so as to form at least two insulating openings in the portion of the transparent conductive layer located in the insulating area and in the transparent layer and the second transmission layer located in the insulating area, and the position where the main light spot irradiates forms a first insulating opening, and the position where the diffraction light spot irradiates forms a second insulating opening.

20. The method for preparing a back contact solar cell according to claim 19, wherein: The diffraction light spots are distributed around the main light spot.

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