A back contact solar cell, cell assembly and photovoltaic system

Abstract

This invention relates to the field of photovoltaic technology, providing a back-contact solar cell, a cell module, and a photovoltaic system. The back-contact solar cell includes: a silicon substrate, comprising a back side and a front side disposed opposite to each other; the back side including a first region and a second region alternately disposed along a first direction, and an isolation region located between the first region and the second region; a first doped layer disposed in the first region; and a second doped layer disposed in the second region; the silicon substrate forms at least one recess and at least one first protrusion in the isolation region, the recess being recessed relative to the surface of the first region and / or the surface of the second region, and the first protrusion being protruding relative to the surface of the first region and / or the surface of the second region; both the recess and the first protrusion extend along a second direction, which intersects with the first direction. The back-contact solar cell of this invention can reduce the short-circuit risk between the first doped layer and the second doped layer, ensuring good power generation efficiency of the back-contact solar cell.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a back-contact solar cell, a cell module, and a photovoltaic system. Background Technology

[0002] In related technologies, the back side of a back-contact solar cell is typically provided with a first doped layer and a second doped layer with opposite doping types. The silicon substrate of the back-contact solar cell is usually provided with a trench between the first doped layer and the second doped layer to isolate the first doped layer and the second doped layer. However, during the metallization process of the back-contact solar cell, that is, when preparing the metal electrode of the back-contact solar cell, metal is easily left in the trench. The metal left in the trench can easily conduct the first doped layer and the second doped layer and cause a short circuit, thereby affecting the power generation efficiency of the back-contact solar cell. Summary of the Invention

[0003] This invention provides a back-contact solar cell, which aims to solve the problem that in existing back-contact solar cells, residual metal in the trench can easily conduct through the first and second doped layers, causing a short circuit and affecting the power generation efficiency of the back-contact solar cell.

[0004] This invention is implemented by providing a back-contact solar cell, comprising: A silicon substrate, the silicon substrate including a back side and a front side disposed opposite to each other, the back side including a first region and a second region disposed alternately at intervals along a first direction, and an isolation region located between the first region and the second region; A first doped layer is disposed in the first region; and A second doped layer is provided in the second region, wherein the doping type of the second doped layer is opposite to that of the first doped layer; The silicon substrate forms at least one recess and at least one first protrusion in the isolation region. The recess is recessed relative to the surface of the first region and / or the surface of the second region, and the first protrusion is protruding relative to the surface of the first region and / or the surface of the second region. Both the recess and the first protrusion extend along a second direction, which intersects with the first direction.

[0005] Preferably, the isolation area forms at least two recesses or at least two first protrusions, and the recesses and the first protrusions are alternately arranged along the first direction.

[0006] Preferably, the isolation area forms two recesses and a first protrusion, with a recess disposed between the first region and the first protrusion, and a recess disposed between the second region and the first protrusion.

[0007] Preferably, the isolation area forms a recess and a first convex portion, the recess being located between the first region and the first convex portion, and the first convex portion being located between the recess and the second region; or, the recess being located between the second region and the first convex portion, and the first convex portion being located between the recess and the first region.

[0008] Preferably, the protrusion height of the first protrusion relative to the surface of the first region and / or the surface of the second region is 3 to 40 micrometers.

[0009] Preferably, the recess depth of the recess relative to the surface of the first region and / or the surface of the second region is 1 to 10 micrometers.

[0010] Preferably, the surface of the recess is provided with a first velvety structure.

[0011] Preferably, the surface of the first protrusion is provided with a second velvety structure.

[0012] Preferably, the distribution density of the second velvet structure is less than the distribution density of the first velvet structure.

[0013] Preferably, a first region, a second region, and an isolation region constitute a repeating unit, and the ratio of the dimension of a single first protrusion along the first direction to the dimension of a single repeating unit along the first direction is 2% to 80%.

[0014] Preferably, the ratio of the dimension of a single first protrusion along the first direction to the dimension of a single concave portion along the first direction is 0.1 to 20.

[0015] Preferably, the size of a single isolation zone along the first direction is 50 to 600 micrometers.

[0016] Preferably, the size of a single first protrusion along the first direction is 10 to 300 micrometers.

[0017] Preferably, the size of a single recess along the first direction is 10 to 300 micrometers.

[0018] Preferably, the first protrusion is continuously disposed in the second direction, and the dimension of the first protrusion along the second direction is the same as the dimension of the recess along the second direction.

[0019] Preferably, the first protrusion is discontinuously arranged in the second direction, and the ratio of the dimension of the first protrusion along the second direction to the dimension of the concave portion along the second direction is greater than 90%.

[0020] Preferably, the first protrusion includes a top surface disposed away from the front side along the thickness direction of the silicon substrate, and at least a portion of the top surface is provided with the second textured structure.

[0021] Preferably, the first protrusion further includes two side surfaces disposed opposite to each other along the first direction, the two side surfaces being respectively connected to the top surface, and at least one side surface being provided with a textured structure.

[0022] Preferably, the first convex portion is located between the concave portion and the first region, and the first doped layer extends to the top surface of the first convex portion; or, the first convex portion is located between the concave portion and the second region, and the second doped layer extends to the top surface of the first convex portion.

[0023] Preferably, the top surface includes a textured area and a polished area, the textured area being provided with a second textured structure; the first protrusion is located between the recess and the first region, and the first doped layer extends to the polished area; or, the first protrusion is located between the recess and the second region, and the second doped layer extends to the polished area.

[0024] Preferably, the silicon substrate forms a second protrusion between partially adjacent first and second regions, the second protrusion protruding relative to the surface of the first region and / or the surface of the second region; A portion of the first doped layer includes a first extension extending onto the second protrusion, and a portion of the second doped layer includes a second extension extending onto the second protrusion, with a leakage tunneling layer disposed between the first extension and the second extension.

[0025] Preferably, the dimension of the second protrusion along the first direction is L, and the distance from the leakage tunneling layer along the first direction to the center of the orthographic projection of the second protrusion on the back side is less than (1 / 3)L.

[0026] Preferred options also include: A first dielectric layer is disposed in the first region, located between the silicon substrate and the first doped layer; and The second dielectric layer is disposed in the second region and is located between the silicon substrate and the second doped layer.

[0027] Preferably, the first dielectric layer and the second dielectric layer are one or a combination of at least two of the following: silicon oxide layer, aluminum oxide layer, silicon carbide layer, silicon nitride layer, silicon oxynitride layer, and intrinsic amorphous silicon layer.

[0028] Preferably, the leakage tunneling layer is connected to the first dielectric layer or the second dielectric layer, and the thickness of the leakage tunneling layer is less than the thickness of at least one of the first dielectric layer and the second dielectric layer.

[0029] Preferably, the projection of the first extension along the thickness direction of the silicon substrate covers at least a portion of the second extension, and an insulating layer is provided between the second extension and the first extension along the thickness direction of the silicon substrate.

[0030] Preferably, the surface of the second protrusion is a polished surface.

[0031] Preferred options also include: A passivation layer that at least covers the first doped layer, the second doped layer, the recess, and the first protrusion.

[0032] Preferred options also include: A first metal electrode is electrically connected to the first doped layer; and The second metal electrode is electrically connected to the second doped layer.

[0033] The present invention also provides a battery assembly including the aforementioned back-contact solar cell.

[0034] The present invention also provides a photovoltaic system including the above-described battery module.

[0035] The present invention provides a silicon substrate for a back-contact solar cell with at least one recess and at least one first protrusion formed in an isolation region. The recess is recessed relative to the surface of a first region and / or the surface of a second region, and the first protrusion is raised relative to the surface of the first region and / or the surface of the second region. Since there is at least one recess and at least one first protrusion between the first region and the second region, the isolation between the first doped layer and the second doped layer is avoided by using only a single recess. The first doped layer and the second doped layer are isolated by at least one recess and at least one first protrusion, which can improve the electrical isolation effect between the first doped layer and the second doped layer. Moreover, due to the presence of the first protrusion, taking advantage of the fact that the first protrusion is not prone to metal residue during the metallization process of the back-contact solar cell, the first protrusion can separate the residual metal in the recess from the first doped layer or the second doped layer, which can prevent the first doped layer and the second doped layer from conducting due to the residual metal in the recess, thereby reducing the risk of short circuit between the first doped layer and the second doped layer, improving the working reliability of the back-contact solar cell, and ensuring the good power generation efficiency of the back-contact solar cell. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the back-contact solar cell portion structure of the first embodiment of the present invention; Figure 2 A cross-sectional schematic diagram of a back-contact solar cell according to a first embodiment of the present invention; Figure 3 This is a cross-sectional schematic diagram of the back contact solar cell portion structure of the first embodiment of the present invention. Figure 4 This is a cross-sectional schematic diagram of the back contact solar cell portion structure provided in the second embodiment of the present invention; Figure 5 This is a schematic diagram of the back-contact solar cell structure of the third embodiment of the present invention. Figure 6 A cross-sectional schematic diagram of a back-contact solar cell according to a third embodiment of the present invention; Figure 7 This is a schematic diagram of the back-contact solar cell portion structure of the fourth embodiment provided in this invention. Figure 8 A cross-sectional schematic diagram of a back-contact solar cell according to a fourth embodiment of the present invention; Figure 9 This is a schematic diagram of the back contact solar cell portion structure of the fifth embodiment of the present invention; Figure 10 A schematic diagram of the back contact solar cell portion structure of the sixth embodiment provided in this invention; Figure 11 This is a cross-sectional schematic diagram of a back-contact solar cell according to the sixth embodiment of the present invention.

[0037] Explanation of key symbols: The back contact solar cell 100 comprises a silicon substrate 1, a back side 11, a front side 12, a first region 111, a second region 112, an isolation region 113, a first direction X, a second direction Y, a first doped layer 2, a second doped layer 3, a recess 15, a first convex portion 16, a first textured structure 151, a second textured structure 161, a first dielectric layer 5, a second dielectric layer 6, a passivation layer 7, a first metal electrode 8, a second metal electrode 9, a second convex portion 17, a first extension 21, a second extension 31, a leakage tunneling layer 10, and an insulating layer 18. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0039] In the description of this invention, it should be understood that the terms "upper", "lower", "back", "front", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0042] Please refer to Figures 1-3 An embodiment of the present invention provides a back-contact solar cell 100, comprising: The silicon substrate 1 includes a back side 11 and a front side 12 disposed opposite to each other. The back side 11 includes a first region 111 and a second region 112 disposed alternately along a first direction X, and an isolation region 113 located between the first region 111 and the second region 112. The first doped layer 2 is disposed in the first region 111; and A second doped layer 3 is provided in the second region 112, and the doping type of the second doped layer 3 is opposite to that of the first doped layer 2; In this embodiment, the silicon substrate 1 forms at least one recess 15 and at least one first protrusion 16 in the isolation region 113. The recess 15 is recessed relative to the surface of the first region 111 and / or the surface of the second region 112, and the first protrusion 16 is protruded relative to the surface of the first region 111 and / or the surface of the second region 112. Both the recess 15 and the first protrusion 16 extend along the second direction Y, which intersects with the first direction X.

[0043] In an embodiment of the present invention, a silicon substrate 1 of a back-contact solar cell 100 has at least one recess 15 and at least one first protrusion 16 formed in an isolation region 113. The recess 15 is recessed relative to the surface of the first region 111 and / or the surface of the second region 112, and the first protrusion 16 is protruding relative to the surface of the first region 111 and / or the surface of the second region 112. The presence of at least one recess 15 and at least one first protrusion 16 between the first region 111 and the second region 112 avoids the first doped layer 2 and the second doped layer 3 being isolated only by a single recess 15. The use of at least one recess 15 and at least one first protrusion 16 to isolate the first doped layer 2 and the second doped layer 3 improves the electrical isolation effect between them. Furthermore, due to the presence of the first protrusion 16, the first region 111 and the second region 112 are not isolated solely by the recess 15. Taking advantage of the first protrusion 16, which is less likely to leave metal residue during the metallization process of the back contact solar cell 100, and even if metal residue remains on the surface of the first protrusion 16, it can be easily cleaned. The first protrusion 16 can separate the residual metal in the recess 15 from the first doped layer 2 or the second doped layer 3, preventing the first doped layer 2 and the second doped layer 3 from conducting due to residual metal in the recess 15, thereby reducing the risk of short circuit between the first doped layer 2 and the second doped layer 3, improving the operational reliability of the back contact solar cell 100, and ensuring the good power generation efficiency of the back contact solar cell 100.

[0044] In this embodiment of the invention, the silicon substrate 1 includes a back side 11 and a front side 12 disposed opposite to each other along the thickness direction Z of the silicon substrate 1. The front side 12 of the silicon substrate 1 is the side of the silicon substrate 1 that mainly receives sunlight when the back contact solar cell 100 is working normally, and the back side 11 of the silicon substrate 1 is the surface opposite to the front side 12 of the silicon substrate 1.

[0045] In this embodiment of the invention, there are multiple first regions 111 and second regions 112. The first regions 111 and second regions 112 are alternately spaced along a first direction X, and an isolation region 113 is provided between adjacent first regions 111 and second regions 112. Both the first regions 111 and second regions 112 extend along a second direction Y, that is, the length direction of both the first regions 111 and 112 is along the second direction Y. Correspondingly, there are multiple first doped layers 2 and second doped layers 3. The first doped layers 2 and second doped layers 3 are alternately spaced along the first direction X, and both extend along the second direction Y, that is, the length direction of both the first doped layers 2 and 3 is along the second direction Y. Each first doped layer 2 is disposed in a corresponding first region 111, and each second doped layer 3 is disposed in a corresponding second region 112. Adjacent first doped layers 2 and second doped layers 3 are isolated by the isolation region 113.

[0046] In this embodiment of the invention, both the first protrusion 16 and the recess 15 extend along the second direction Y, that is, the length direction of both the first protrusion 16 and the recess 15 is along the second direction Y. The dimension of the recess 15 along the second direction Y is equal to the dimension of the first doped layer 2 or the second doped layer 3 along the second direction Y, and the dimensions of the first protrusion 16 and the recess 15 along the second direction Y can be the same or different.

[0047] The first direction X and the second direction Y can be perpendicular or not. Preferably, the first direction X and the second direction Y are perpendicular, that is, one of the first direction X and the second direction Y is the length direction of the silicon substrate 1 and the other is the width direction of the silicon substrate 1.

[0048] In this embodiment of the invention, one of the first doped layer 2 and the second doped layer 3 is a P-type doped layer, and the other is an N-type doped layer, and the specific doping type of the first doped layer 2 and the second doped layer 3 is not limited. Specifically, the first doped layer 2 can be a P-type doped layer and the second doped layer 3 can be an N-type doped layer; or the first doped layer 2 can be an N-type doped layer and the second doped layer 3 can be a P-type doped layer. The P-type doped layer is doped with a P-type doping element, that is, it is doped with P-type doped atoms; the N-type doped layer is doped with an N-type doping element, that is, it is doped with N-type doped atoms. The P-type doping element is a Group IIIA element in the periodic table, and the N-type doping element is a Group VA element in the periodic table. For example, the P-type doping element can be boron, and the N-type doping element can be phosphorus. The first doped layer 2 and the second doped layer 3 are at least one of a doped polycrystalline silicon layer, a doped microcrystalline silicon layer, and a doped nanocrystalline silicon layer. Preferably, both the first doped layer 2 and the second doped layer 3 are doped polycrystalline silicon layers.

[0049] In this embodiment of the invention, the recess 15 is specifically a groove, and the specific shape of the recess 15 is not limited.

[0050] Please refer to Figure 3 and Figure 4 In this embodiment of the invention, the surface of the first region 111 is the surface of the silicon substrate 1 located in the first region 111, and the surface of the second region 112 is the surface of the silicon substrate 1 in the second region 112. The surfaces of the first region 111 and the second region 112 can be flush, that is, the surfaces of the first region 111 and the second region 112 are located at the same height position on the silicon substrate 1; or the surfaces of the first region 111 and the second region 112 can have a height difference, that is, the surfaces of the first region 111 and the second region 112 are located at different height positions on the silicon substrate 1. The recess 15 is recessed relative to the surface of the first region 111 and / or the surface of the second region 112. This can be understood as the recess 15 being recessed only relative to the surface of the first region 111 or the surface of the second region 112, or the recess 15 being recessed simultaneously relative to the surfaces of the first region 111 and the second region 112. That is, the bottom surface 150 of the recess 15 is closer to the front surface 12 than at least one of the surfaces of the first region 111 and the second region 112. Figure 3 As shown, the recess 15 is simultaneously recessed relative to the surface of the first region 111 and the surface of the second region 112; as Figure 4 As shown, the recess 15 is recessed only relative to the surface of the first region 111.

[0051] Please refer to Figure 3 and Figure 4 Specifically, taking the center plane P along the thickness direction Z of the silicon substrate 1 as the reference plane, the distance H3 from the bottom surface 150 of the recess 15 to the center plane P is less than the distance H1 from the plane containing the first region 111 to the center plane P and / or the distance H2 from the plane containing the second region 112 to the center plane P. The center plane P along the thickness direction Z of the silicon substrate 1 is parallel to the plane containing the front surface 12 and the first region 111, and is located between the plane containing the front surface 12 and the first region 111. The center plane P along the thickness direction Z of the silicon substrate 1 can be located at the center or a non-center position between the plane containing the front surface 12 and the first region 111; or, the center plane P along the thickness direction Z of the silicon substrate 1 is parallel to the plane containing the front surface 12 and the second region 112, and is located between the plane containing the front surface 12 and the second region 112. The center plane P along the thickness direction Z of the silicon substrate 1 can be located at the center or a non-center position between the plane containing the front surface 12 and the second region 112.

[0052] The distance H3 from the bottom surface 150 of the recess 15 to the central plane P is the average distance from the bottom surface 150 of the recess 15 to the central plane P along the thickness direction Z of the silicon substrate 1. For example, 5 to 10 measurement points are selected on the bottom surface 150 of the recess 15, and the arithmetic mean of the distances from these measurement points along the thickness direction Z of the silicon substrate 1 to the central plane P is calculated as the distance H3 from the bottom surface 150 of the recess 15 to the central plane P. Similarly, the distance H1 from the plane containing the first region 111 to the central plane P is the average distance from the plane containing the first region 111 to the central plane P along the thickness direction Z of the silicon substrate 1. For example, 5 to 10 measurement points are selected on the plane containing the first region 111, and the arithmetic mean of the distances from these measurement points along the thickness direction Z of the silicon substrate 1 to the central plane P is calculated as the distance H1 from the plane containing the first region 111 to the central plane P. The distance H2 from the plane containing the second region 112 to the central plane P is the average distance from the plane containing the second region 112 along the thickness direction Z of the silicon substrate 1 to the central plane P. For example, 5 to 10 measurement points are selected on the plane containing the second region 112, and the arithmetic mean of the distances from these measurement points along the thickness direction Z of the silicon substrate 1 to the central plane P is calculated as the distance H2 from the plane containing the second region 112 to the central plane P. Figure 3 As shown, the recess 15 is simultaneously recessed relative to the surfaces of the first region 111 and the second region 112. The distance H3 from the bottom surface 150 of the recess 15 to the central plane P is less than the distance H1 from the plane containing the first region 111 to the central plane P and the distance H2 from the plane containing the second region 112 to the central plane P. Figure 4 As shown, the recess 15 is recessed relative to the surface of the first region 111. The distance H3 from the bottom surface 150 of the recess 15 to the central plane P is less than the distance H1 from the plane where the first region 111 is located to the central plane P, and the distance H3 from the bottom surface 150 of the recess 15 to the central plane P is greater than the distance H2 from the plane where the second region 112 is located to the central plane P.

[0053] In a preferred embodiment of the present invention, the distance H3 from the bottom surface 150 of the recess 15 to the central plane P is less than the distance H1 from the plane containing the first region 111 to the central plane P and the distance H2 from the plane containing the second region 112 to the central plane P. At this time, the recess 15 is recessed relative to the surface of the first region 111 and the surface of the second region 112, which can further improve the electrical isolation effect of the recess 15 between the first doped layer 2 and the second doped layer 3.

[0054] In this embodiment of the invention, the first protrusion 16 is specifically an elongated protrusion, and the specific shape of the cross-section of the first protrusion 16 is not limited. For example, the cross-section of the first protrusion 16 can be square, trapezoidal, or semi-circular. The first protrusion 16 protrudes relative to the surface of the first region 111 and / or the surface of the second region 112, that is, the top surface 160 of the first protrusion 16 is higher than at least one of the surfaces of the first region 111 and the second region 112.

[0055] In this embodiment of the invention, the first protrusion 16 includes a top surface 160 disposed away from the front surface 12 along the thickness direction of the silicon substrate 1. Taking the central plane P in the thickness direction Z of the silicon substrate 1 as a reference plane, the distance H4 from the top surface 160 of the first protrusion 16 to the central plane P is greater than the distance H1 from the plane containing the first region 111 to the central plane P and / or the distance H2 from the plane containing the second region 112 to the central plane P.

[0056] Similarly, the distance H4 from the top surface 160 of the first protrusion 16 to the central plane P is the average distance from the top surface 160 of the first protrusion 16 to the central plane P along the thickness direction Z of the silicon substrate 1. For example, 5 to 10 measurement points are selected on the top surface 160 of the first protrusion 16, and the arithmetic mean of the distances from these measurement points to the central plane P along the thickness direction Z of the silicon substrate 1 is calculated as the distance H4 from the top surface 160 of the first protrusion 16 to the central plane P.

[0057] In this embodiment of the invention, the first protrusion 16 protrudes in a direction away from the silicon substrate 1 relative to the surface of the first region 111 and / or the surface of the second region 112. The first protrusion 16 protrudes relative to the bottom surface 150 of the recess 15, and the first protrusion 16 protrudes relative to the surface of the first region 111 and / or the surface of the second region 112. The first protrusion 16 protruding relative to the surface of the first region 111 and / or the surface of the second region 112 can be understood as follows: the first protrusion 16 may protrude only relative to the surface of the first region 111 or the surface of the second region 112, or the first protrusion 16 may protrude simultaneously relative to the surfaces of the first region 111 and the second region 112. That is, the top surface 160 of the first protrusion 16 is further away from the front surface 12 relative to at least one of the surfaces of the first region 111 and the second region 112. Figure 3 As shown, the first protrusion 16 protrudes simultaneously from the surfaces of the first region 111 and the second region 112. The distance H4 from the top surface 160 of the first protrusion 16 to the central plane P is greater than the distance H1 from the plane containing the first region 111 to the central plane P and the distance H2 from the plane containing the second region 112 to the central plane P. This allows for better electrical isolation between the first doped layer 2 and the second doped layer 3. Figure 4As shown, the first protrusion 16 protrudes only relative to the surface of the second region 112. The distance H4 from the top surface 160 of the first protrusion 16 to the central plane P is less than the distance H1 from the plane where the first region 111 is located to the central plane P, and the distance H4 from the top surface 160 of the first protrusion 16 to the central plane P is greater than the distance H2 from the plane where the second region 112 is located to the central plane P. This can avoid the first protrusion 16 from being too high, reduce the stress concentration of the silicon substrate 1, and help improve the structural stability of the battery.

[0058] Please refer to this again. Figure 2 and Figure 3 As one embodiment of the present invention, it further includes: The first dielectric layer 5 is disposed in the first region 111, located between the silicon substrate 1 and the first doped layer 2; and The second dielectric layer 6 is located in the second region 112 between the silicon substrate 1 and the second doped layer 3.

[0059] In this embodiment, the first dielectric layer 5 is disposed between the first doped layer 2 and the silicon substrate 1, and the second dielectric layer 6 is disposed between the second doped layer 3 and the silicon substrate 1. The first dielectric layer 5 and the second dielectric layer 6 passivate the surface of the silicon substrate 1 and allow carriers to pass through efficiently. The materials of the first dielectric layer 5 and the second dielectric layer 6 can be the same or different.

[0060] As an embodiment of the present invention, the first dielectric layer 5 and the second dielectric layer 6 are respectively one or a combination of at least two of the following: silicon oxide layer, aluminum oxide layer, silicon carbide layer, silicon nitride layer, silicon oxynitride layer, and intrinsic amorphous silicon layer.

[0061] In this embodiment, the first dielectric layer 5 and the second dielectric layer 6 are each one of a silicon oxide layer, an aluminum oxide layer, a silicon carbide layer, a silicon nitride layer, a silicon oxynitride layer, and an intrinsic amorphous silicon layer, or they can be a stacked structure of at least two of the following: silicon oxide layer, aluminum oxide layer, silicon carbide layer, silicon nitride layer, silicon oxynitride layer, and intrinsic amorphous silicon layer. Preferably, the first dielectric layer 5 and the second dielectric layer 6 are both silicon oxide layers.

[0062] Please refer to Figures 1-3 As an embodiment of the present invention, the isolation region 113 forms at least two recesses 15, and the recesses 15 and the first protrusion 16 are alternately arranged along the first direction X.

[0063] In this embodiment, each isolation region 113 has at least two recesses 15 and at least one first protrusion 16. The recesses 15 and the first protrusions 16 are alternately arranged along the first direction X. The first doped layer 2 and the second doped layer 3 are isolated by the alternately arranged recesses 15 and first protrusions 16 along the first direction X, which can further improve the electrical isolation effect between the first region 111 and the second region 112. Moreover, it can further reduce the risk of residual metal in the recesses 15 causing the first doped layer 2 and the second doped layer 3 to conduct electricity, further improving the operational reliability of the back contact solar cell 100 and ensuring good power generation efficiency of the back contact solar cell 100. Figures 1-3 Each isolation zone 113 shown in the diagram forms two recesses 15 and a first protrusion 16, with the two recesses 15 and the first protrusion 16 alternately arranged along the first direction X.

[0064] Please refer to Figure 5 and Figure 6 In another embodiment of the present invention, the isolation region 113 forms at least two first protrusions 16, and the recesses 15 and the first protrusions 16 are alternately arranged along the first direction X.

[0065] In this embodiment, each isolation region 113 has at least two first protrusions 16 and at least one recess 15. The recess 15 and the first protrusions 16 are alternately arranged along the first direction X. The first doped layer 2 and the second doped layer 3 are isolated by the alternately arranged recesses 15 and first protrusions 16 along the first direction X, which can improve the electrical isolation effect between the first doped layer 2 and the second doped layer 3. Moreover, since there are at least two first protrusions 16, at least one first protrusion 16 separates the recess 15 from the first region 111, and at least one first protrusion 16 separates the recess 15 from the second region 112, which can further reduce the risk of residual metal in the recess 15 causing conductivity between the first doped layer 2 and the second doped layer 3, further improving the operational reliability of the back contact solar cell 100 and ensuring good power generation efficiency of the back contact solar cell 100. Figures 5-6 The diagram illustrates that each isolation zone 113 forms two first protrusions 16 and one recess 15, with the recess 15 located between the two first protrusions 16.

[0066] Please refer to this again. Figures 1-3 As an embodiment of the present invention, the isolation region 113 forms two recesses 15 and a first protrusion 16. A recess 15 is provided between the first region 111 and the first protrusion 16, and a recess 15 is provided between the second region 112 and the first protrusion 16.

[0067] In this embodiment, each isolation region 113 forms two recesses 15 and one first protrusion 16. The first protrusion 16 is located between the two recesses 15, avoiding an excessive number of recesses 15 and first protrusions 16, which facilitates the processing of the isolation region 113. Moreover, the first protrusion 16 separates the two recesses 15, which can effectively prevent residual metal in the two recesses 15 from conducting the first doped layer 2 and the second doped layer 3, further improving the operational reliability of the back contact solar cell 100. At the same time, the combination of the two recesses 15 and the first protrusion 16 can achieve a good electrical isolation effect between the first doped layer 2 and the second doped layer 3.

[0068] Please refer to this again. Figures 7-8 In another embodiment of the present invention, the isolation region 113 forms a recess 15 and a first protrusion 16, the recess 15 being located between the first region 111 and the first protrusion 16, and the first protrusion 16 being located between the recess 15 and the second region 112; or, the recess 15 being located between the second region 112 and the first protrusion 16, and the first protrusion 16 being located between the recess 15 and the first region 111.

[0069] In this embodiment, the isolation region 113 forms a recess 15 and a first protrusion 16. The first doped layer 2 and the second doped layer 3 are isolated by the recess 15 and the first protrusion 16, which achieves good electrical isolation between the first doped layer 2 and the second doped layer 3. Furthermore, the first protrusion 16 prevents residual metal in the recess 15 from conducting between the first doped layer 2 and the second doped layer 3. Since only one recess 15 and one first protrusion 16 are needed, the manufacturing process of the back-contact solar cell 100 is simplified, reducing production costs. Figure 7 and Figure 8 The illustration only shows the situation where the first protrusion 16 is positioned close to the second region 112.

[0070] In some embodiments, when the isolation region 113 forms at least two recesses 15, the depths of the at least two recesses 15 are different; or, when the isolation region 113 forms at least two first protrusions 16, the heights of the at least two first protrusions 16 are different. Since there is a depth difference between the at least two recesses 15 or a height difference between the at least two first protrusions 16, the risk of residual metal in the recesses 15 causing the first doped layer 2 and the second doped layer 3 to conduct can be further reduced, and the operational reliability of the back contact solar cell 100 can be further improved.

[0071] As an embodiment of the present invention, the first protrusion 16 is located between the recess 15 and the first region 111, and the first doped layer 2 extends to the top surface 160 of the first protrusion 16; or, the first protrusion 16 is located between the recess 15 and the second region 112, and the second doped layer 3 extends to the top surface 160 of the first protrusion 16.

[0072] In this embodiment, when the first protrusion 16 is located between the recess 15 and the first region 111, the first doped layer 2 extends to the top surface 160 of the first protrusion 16, while the second doped layer 3 does not extend onto the first protrusion 16. Due to the presence of the first protrusion 16, there is a height difference between the second doped layer 3 and the first doped layer 2, which reduces the risk of conductivity between the second doped layer 3 and the first doped layer 2, and increases the area of ​​the first doped layer 2, thereby improving the battery's power generation efficiency. Similarly, when the first protrusion 16 is located between the recess 15 and the second region 112, and the second doped layer 3 extends to the top surface 160 of the first protrusion 16, while the first doped layer 2 does not extend onto the first protrusion 16, the presence of the first protrusion 16 again creates a height difference between the second doped layer 3 and the first doped layer 2, which also reduces the risk of conductivity between the second doped layer 3 and the first doped layer 2, and increases the area of ​​the second doped layer 3, thereby improving the battery's power generation efficiency.

[0073] Please refer to this again. Figures 1-3 As an embodiment of the present invention, the protrusion height of the first protrusion 16 relative to the surface of the first region 111 and / or the surface of the second region 112 is 3 to 40 micrometers.

[0074] In this embodiment, the protrusion height of the first protrusion 16 relative to the surface of the first region 111 and / or the surface of the second region 112 is 3-40 micrometers. Specifically, the protrusion height of the first protrusion 16 relative to the surface of the first region 111 or the surface of the second region 112 can be 3-40 micrometers, or the protrusion height of the first protrusion 16 relative to the surface of the first region 111 and the surface of the second region 112 can both be 3-40 micrometers. The protrusion height of the first protrusion 16 relative to the surface of the first region 111 or the surface of the second region 112 is the distance from the top surface 160 of the first protrusion 16 along the thickness direction Z of the silicon substrate 1 to the surface of the first region 111 or the surface of the second region 112. By controlling the protrusion height of the first protrusion 16 relative to the surface of the first region 111 and / or the surface of the second region 112 to be 3-40 micrometers, good electrical isolation between the first protrusion 16 and the first doped layer 2 and the second doped layer 3 can be achieved. Furthermore, by ensuring a suitable height difference between the top surface 160 of the first protrusion 16 and the bottom surface 150 of the recess 15, residual metal in the recess 15 can be prevented from conducting the first doped layer 2 and the second doped layer 3. Figure 3 The first protrusion 16 shown in the diagram has the same protrusion height relative to the surface of the first region 111 and the surface of the second region 112, and both are H6.

[0075] For example, the protrusion height of the first protrusion 16 relative to the surface of the first region 111 and / or the surface of the second region 112 can be any value among 3 micrometers, 4 micrometers, 5 micrometers, 6 micrometers, 8 micrometers, 10 micrometers, 12 micrometers, 14 micrometers, 15 micrometers, 17 micrometers, 19 micrometers, 20 micrometers, 22 micrometers, 25 micrometers, 33 micrometers, 35 micrometers, 37 micrometers, 38 micrometers, and 40 micrometers.

[0076] As an embodiment of the present invention, the recess 15 has a recess depth of 1 to 10 micrometers relative to the surface of the first region 111 and / or the surface of the second region 112.

[0077] In this embodiment, the recess 15 can be recessed relative to the surface of the first region 111 or the surface of the second region 112, or it can be recessed simultaneously relative to both the surfaces of the first region 111 and the second region 112. When the recess 15 is recessed relative to the surface of the first region 111, the recess depth is 1-10 micrometers; when the recess 15 is recessed relative to the surface of the second region 112, the recess depth is 1-10 micrometers; when the recess 15 is recessed simultaneously relative to both the surfaces of the first region 111 and the second region 112, the recess depth is 1-10 micrometers. Figure 3 The recess 15 shown in the diagram has the same depth relative to the surface of the first region 111 and the surface of the second region 112, and both are H5.

[0078] In this embodiment, the recess depth of the recess 15 relative to the surface of the first region 111 and / or the surface of the second region 112 is controlled to be 1~10 micrometers. This can ensure good electrical isolation between the recess 15 and the first doped layer 2 and the second doped layer 3, and can prevent the recess 15 from being too deep, which would cause metal to remain in the recess 15. This further reduces the risk of residual metal in the recess 15 causing the first doped layer 2 and the second doped layer 3 to conduct.

[0079] As an embodiment of the present invention, the surface of the recess 15 is provided with a first velvet structure 151.

[0080] In this embodiment, the bottom surface 150 of the recess 15 may be provided with a first textured surface structure 151. By providing the first textured surface structure 151 on the surface of the recess 15, it is beneficial to increase the absorption of sunlight incident on the back side 11 by the recess 15, thereby improving the power generation efficiency of the back side 11 of the battery. Of course, the side wall surface of the recess 15 may also be provided with the first textured surface structure 151.

[0081] In this embodiment, the first textured structure 151 includes at least one of a regular pyramid, an inverted pyramid, a nanopillar, and a nanopore.

[0082] In this embodiment, the specific structure of the first textured surface 151 is not limited, and it can be one of a regular pyramid, an inverted pyramid, a nanopillar, or a nanopore. The first textured surface 151 can also be a combination of at least two of the following: a regular pyramid, an inverted pyramid, a nanopillar, and a nanopore. Setting the first textured surface 151 to include at least one of the following can achieve a good light-trapping effect, which is beneficial for improving the absorption of incident sunlight on the back side 11 and increasing the power generation efficiency of the battery's back side 11.

[0083] In addition, in order to reduce the reflection of sunlight by the front 12, the front 12 is also provided with a velvety surface, which is not shown in the attached figure.

[0084] As an embodiment of the present invention, the surface of the first protrusion 16 is provided with a second velvet structure 161.

[0085] In this embodiment, the top surface 160 and the side surface 162 of the first protrusion 16 can both be provided with a second textured structure 161. By providing a second textured structure 161 on the surface of the first protrusion 16, it is beneficial to increase the absorption of sunlight incident on the back side 11 by the first protrusion 16 and improve the power generation efficiency of the back side 11 of the battery.

[0086] The second textured structure 161 may also include at least one of the following: a regular pyramid, an inverted pyramid, a nanopillar, and a nanopore.

[0087] As an embodiment of the present invention, the first protrusion 16 includes a top surface 160 disposed away from the front surface 12 along the thickness direction Z of the silicon substrate 1, and the top surface 160 is provided with a second textured structure 161 in at least a portion of its area.

[0088] In this embodiment, the top surface 160 of the first protrusion 16 is provided with a second textured structure 161. By providing the second textured structure 161 on the top surface 160 of the first protrusion 16, it is beneficial to increase the absorption of sunlight incident on the back side 11 by the first protrusion 16 and improve the power generation efficiency of the back side 11 of the battery.

[0089] As an embodiment of the present invention, the first protrusion 16 further includes two side surfaces 162 disposed opposite to each other along the first direction X, the two side surfaces 162 being connected to the top surface 160 respectively, and at least one side surface 162 being provided with a textured structure (not shown).

[0090] The textured structure can be strip-shaped protrusions or dot-shaped protrusions. By providing a second velvety structure 161 on the top surface 160 of the first protrusion 16 and providing a textured structure on at least one side 162 of the first protrusion 16, it is beneficial to further increase the absorption of incident sunlight on the back side 11 by the first protrusion 16, thereby improving the power generation efficiency of the back side 11 of the battery. Preferably, both sides 162 of the first protrusion 16 are provided with textured structures.

[0091] As an embodiment of the present invention, the distribution density of the second pile structure 161 is less than the distribution density of the first pile structure 151.

[0092] In this embodiment, the distribution density of the second velvet structure 161 is the number of second velvet structures 161 per unit area, that is, the ratio of the number of second velvet structures 161 per unit area to the unit area. The distribution density of the first velvet structure 151 is the number of first velvet structures 151 per unit area, that is, the ratio of the number of first velvet structures 151 per unit area to the unit area. The distribution density of the second textured structure 161 is smaller than that of the first textured structure 151, meaning that there are more first textured structures 151 per unit area. This results in a higher distribution density of the first textured structure 151 compared to the second textured structure 161, which can improve the light-trapping ability of the recess 15 and facilitate the absorption of photogenerated carriers. Conversely, the distribution density of the second textured structure 161 is lower than that of the first textured structure 151. This allows the diameter and height of a single second textured structure 161 to be larger than those of a single first textured structure 151, increasing the barrier effect of the second textured structure 161 on the migration of metal elements. This can further reduce the risk of the first doped layer 2 and the second doped layer 3 becoming conductive due to residual metal in the recess 15.

[0093] Please refer to this again. Figure 8 As an embodiment of the present invention, the top surface 160 includes a textured area 1601 and a polished area 1602. The textured area 1601 is provided with a second textured structure 161. A first protrusion 16 is located between the recess 15 and the first region 111, and a first doped layer 2 extends to the polished area 1602. Alternatively, the first protrusion 16 is located between the recess 15 and the second region 112, and a second doped layer 3 extends to the polished area 1602.

[0094] In this embodiment, when the first doped layer 2 extends to the top surface 160 of the first protrusion 16 or the second doped layer 3 extends to the top surface 160 of the first protrusion 16, the top surface 160 of the first protrusion 16 is configured to include a textured area 1601 and a polished area 1602. The area of ​​the top surface 160 of the first protrusion 16 covered by the first doped layer 2 or the second doped layer 3 is the polished area 1602, which can reduce the recombination loss of the first doped layer 2 or the second doped layer 3 located in the polished area 1602. Specifically, the polished area 1602 is a polished surface. Moreover, since the area of ​​the top surface 160 of the first protrusion 16 not covered by the first doped layer 2 or the second doped layer 3 is the textured area 1601, the textured area 1601 is provided with a second textured structure 161. The second textured structure 161 can be used to achieve good absorption of sunlight incident on the back side 11. Therefore, this embodiment can achieve a balance between optical gain and low recombination loss, and better improve battery efficiency.

[0095] In this embodiment, when the first protrusion 16 is located between the recess 15 and the first region 111, the first doped layer 2 extends to the polished surface region 1602, and the first dielectric layer 5 extends between the polished surface region 1602 and the first doped layer 2; when the first protrusion 16 is located between the recess 15 and the second region 112, the second doped layer 3 extends to the polished surface region 1602, and the second dielectric layer 6 extends between the polished surface region 1602 and the second doped layer 3, thereby improving the passivation effect at the polished surface region 1602. Figure 8 The illustration only shows the case where the first protrusion 16 is located between the recess 15 and the second region 112, and the second doped layer 3 and the second dielectric layer 6 extend to the first protrusion 16.

[0096] Please refer to this again. Figures 1-3 As an embodiment of the present invention, a first region 111, a second region 112, and an isolation region 113 constitute a repeating unit, and the ratio of the dimension of a single first protrusion 16 along the first direction X to the dimension of a single repeating unit along the first direction X is 2% to 80%.

[0097] In this embodiment, a first region 111, a second region 112, and an isolation region 113 constitute a repeating unit, and the back-contact solar cell 100 includes a plurality of repeating units arranged sequentially along the first direction X. The dimension of a single repeating unit along the first direction X is the sum of the dimensions of the first region 111, the second region 112, and the isolation region 113 along the first direction X. By controlling the ratio of the dimension of a single first protrusion 16 along the first direction X to the dimension of a single repeating unit along the first direction X to be 2% to 80%, good electrical isolation between the first protrusion 16 and the first doped layer 2 and the second doped layer 3 can be achieved, and the first protrusion 16 can effectively prevent the problem of residual metal in the recess 15 causing conductivity between the first doped layer 2 and the second doped layer 3. More preferably, the ratio of the dimension of a single first protrusion 16 along the first direction X to the dimension of a single repeating unit along the first direction X is 10% to 60%.

[0098] As an embodiment of the present invention, the ratio of the dimension of a single first protrusion 16 along the first direction X to the dimension of a single recess 15 along the first direction X is 0.1 to 20.

[0099] In this embodiment, the ratio of the size of a single first protrusion 16 along the first direction X to the size of a single recess 15 along the first direction X is controlled to be 0.1 to 20. The ratio of the size of the first protrusion 16 and the recess 15 along the first direction X is controlled within this range. Under the premise that the size of the isolation region 113 along the first direction X is constant, the width of the first protrusion 16 is avoided from being too small, which would cause the width of the recess 15 to be too large. This can prevent the problem that the recess 15 is too wide and metal is easily left inside, which would cause the first doped layer 2 and the second doped layer 3 to become conductive. At the same time, the width of the first protrusion 16 is avoided from being too large, which would cause the width of the recess 15 to be too small, thus ensuring a good isolation effect between the first doped layer 2 and the second doped layer 3.

[0100] As an embodiment of the present invention, the size of a single isolation region 113 along the first direction X is 50 to 600 micrometers.

[0101] In this embodiment, the size of a single isolation region 113 along the first direction X is 50-600 micrometers. This reduces the precision requirements for laser etching of the isolation region 113, making it easier to achieve through modifications to existing process equipment. Simultaneously, the isolation region 113 provides good insulation between the first doped layer 2 and the second doped layer 3. Furthermore, if the width of the isolation region 113 is too small, it will be difficult to form a structure that combines the first protrusion 16 and the concave portion 15. If the width of the isolation region 113 is too large, excessive laser production capacity will be sacrificed during laser processing, resulting in cost waste. It will also reduce the area ratio of the first region 111 and the second region 112, thereby reducing the separation capability of photogenerated carriers. Therefore, controlling the size of a single isolation region 113 along the first direction X to 50-600 micrometers facilitates the formation of the first protrusion 16 and the concave portion 15, achieving low cost, while ensuring a sufficient area ratio of the first region 111 and the second region 112 on the back surface 11, thus ensuring good battery efficiency.

[0102] For example, the size of a single isolation zone 113 along the first direction X can be any value among 50 micrometers, 55 micrometers, 60 micrometers, 70 micrometers, 85 micrometers, 90 micrometers, 100 micrometers, 120 micrometers, 145 micrometers, 150 micrometers, 200 micrometers, 230 micrometers, 250 micrometers, 300 micrometers, 320 micrometers, 350 micrometers, 380 micrometers, 400 micrometers, 450 micrometers, 500 micrometers, 550 micrometers, and 600 micrometers.

[0103] As an embodiment of the present invention, the size of a single first protrusion 16 along the first direction X is 10 to 300 micrometers.

[0104] In this embodiment, if the width of the first protrusion 16 along the first direction X is too small, it is difficult to control the laser precision to form the first protrusion 16 precisely; if the width of the first protrusion 16 is too large, it will squeeze the area of ​​the recess 15; if the area of ​​the recess 15 is too small, its light-trapping ability will decrease. Therefore, controlling the size of a single first protrusion 16 along the first direction X to be 10~300 micrometers can ensure a suitable area ratio of the recess 15 and ensure good light-trapping ability of the recess 15; moreover, the width of the first protrusion 16 within this range can also effectively prevent the problem of residual metal in the recess 15 causing conductivity between the first doped layer 2 and the second doped layer 3.

[0105] As an embodiment of the present invention, the size of a single recess 15 along the first direction X is 10 to 300 micrometers.

[0106] In this embodiment, the size of a single recess 15 along the first direction X is 10~300 micrometers, which can ensure a suitable area ratio of the recess 15 and ensure good light trapping ability of the recess 15. Moreover, it can prevent metal from being deposited in the recess 15 and facilitate the cleaning of residual metal in the recess 15. This can further prevent the problem of residual metal in the recess 15 causing the first doped layer 2 and the second doped layer 3 to conduct, and can ensure good electrical isolation effect of the recess 15 on the first doped layer 2 and the second doped layer 3.

[0107] like Figure 1 As shown, in one embodiment of the present invention, the first protrusion 16 is continuously provided in the second direction Y, and the size of the first protrusion 16 along the second direction Y is the same as the size of the recess 15 along the second direction Y.

[0108] In this embodiment, the first protrusion 16 is continuously arranged in the second direction Y. The size of the first protrusion 16 along the second direction Y is the same as the size of the recess 15 along the second direction Y, so that any position of the recess 15 between the first doped layer 2 and the second doped layer 3 is separated by the first protrusion 16. This can better prevent the problem of residual metal in the recess 15 from conducting the first doped layer 2 and the second doped layer 3.

[0109] Please refer to Figure 9 As an embodiment of the present invention, the first protrusion 16 is provided intermittently in the second direction Y, and the ratio of the size of the first protrusion 16 in the second direction Y to the size of the concave portion 15 in the second direction Y is greater than 90%.

[0110] In this embodiment, the first protrusion 16 is discontinuously arranged in the second direction Y, that is, the first protrusion 16 is not continuously arranged in the second direction Y, and the ratio of the dimension of the first protrusion 16 along the second direction Y to the dimension of the recess 15 along the second direction Y is greater than 90%. This can also reduce the risk of the first doped layer 2 and the second doped layer 3 being conductive due to metal residue in the recess 15 to a certain extent. In this embodiment, the dimension of the first protrusion 16 along the second direction Y is the total length of a single first protrusion 16 along the second direction Y. Specifically, a single first protrusion 16 is divided into multiple protrusions along the second direction Y, and the sum of the dimensions of the multiple protrusions along the second direction Y is the dimension of a single first protrusion 16 along the second direction Y.

[0111] Please refer to this again. Figure 2 , Figure 6 and Figure 8 As one embodiment of the present invention, it further includes: The passivation layer 7 covers at least the first doped layer 2, the second doped layer 3, the recess 15, and the first protrusion 16.

[0112] In this embodiment, the passivation layer 7 can specifically be one or a stack of at least two of the following: an aluminum oxide layer, a silicon nitride layer, and a silicon oxynitride layer. The passivation layer 7 covers at least the first doped layer 2, the second doped layer 3, the recess 15, and the first protrusion 16. By providing the passivation layer 7, the passivation effect of the back surface 11 can be improved.

[0113] As one embodiment of the present invention, it also includes: The first metal electrode 8 is electrically connected to the first doped layer 2; and The second metal electrode 9 is electrically connected to the second doped layer 3.

[0114] In this embodiment, the first metal electrode 8 passes through the passivation layer 7 and is electrically connected to the first doped layer 2, and the second metal electrode 9 passes through the passivation layer 7 and is electrically connected to the second doped layer 3.

[0115] In this embodiment, the first metal electrode 8 and the second metal electrode 9 have opposite polarities, and the first metal electrode 8 and the second metal electrode 9 are alternately spaced along the first direction X. Both the first metal electrode 8 and the second metal electrode 9 can be silver electrodes or aluminum electrodes. The first metal electrode 8 is in direct contact with the first doped layer 2 to form an electrical connection, and the second metal electrode 9 is in direct contact with the second doped layer 3 to form an electrical connection. Alternatively, the first metal electrode 8 and the first doped layer 2 can also be indirectly contacted to form an electrical connection, and the second metal electrode 9 and the second doped layer 3 can also be indirectly contacted to form an electrical connection.

[0116] Please refer to Figure 10 and Figure 11 As an embodiment of the present invention, a second protrusion 17 is formed between partially adjacent first regions 111 and second regions 112 in the silicon substrate 1. The second protrusion 17 protrudes relative to the surface of the first region 111 and / or the surface of the second region 112. A portion of the first doped layer 2 includes a first extension 21 extending to the second protrusion 17, and a portion of the second doped layer 3 includes a second extension 31 extending to the second protrusion 17. A leakage tunneling layer 10 is provided between the first extension 21 and the second extension 31.

[0117] In this embodiment, the second protrusion 17 protrudes in a direction away from the silicon substrate 1 relative to the surface of the first region 111 and / or the surface of the second region 112. The second protrusion 17 may protrude only relative to the surface of the first region 111 or the surface of the second region 112, or it may protrude simultaneously relative to both surfaces. Preferably, the second protrusion 17 protrudes simultaneously relative to both surfaces, which facilitates a higher height design for the second protrusion 17, thereby increasing its surface area.

[0118] In this embodiment, the second protrusion 17 can specifically be a boss. The specific number of second protrusions 17 and their specific positions within the battery cell are not limited and can be flexibly adjusted according to actual needs.

[0119] In this embodiment, the first extension 21 and the second extension 31 form a leakage contact structure through the leakage tunneling layer 10, which connects the first extension 21 and the second extension 31. When the back contact solar cell 100 is shaded, and a certain reverse voltage is provided to the shaded back contact solar cell 100, the current can be transmitted through the first extension 21, the leakage tunneling layer 10, and the second extension 31. The leakage tunneling layer 10 conducts the first doped layer 2 and the second doped layer 3, preventing the shaded cell from becoming a load that consumes the energy generated by other illuminated cells. This ensures that the conversion efficiency of the back contact solar cell 100 is basically not lost, and also prevents overheating when the back contact solar cell 100 is shaded, reducing the risk of hot spots and ensuring the safety and reliable power generation of the battery module. When the first doped layer 2 and the second doped layer 3 are connected, a large amount of heat will be generated at the location of the first extension 21 and the second extension 31. Due to the setting of the second protrusion 17, the second protrusion 17 can increase the surface area of ​​the silicon substrate 1 at the location of the leakage tunneling layer 10. The leakage tunneling layer 10 between the first extension 21 and the second extension 31 is located on the second protrusion 17. The second protrusion 17 can dissipate the heat generated when the first extension 21 and the second extension 31 are connected in time, thereby preventing the cell temperature from rising sharply, ensuring the safety performance of the battery, and improving the battery's resistance to hot spot risk.

[0120] As an embodiment of the present invention, the second protrusion 17 has a dimension of L along the first direction X, and the distance from the leakage tunneling layer 10 along the first direction X to the center of the orthographic projection of the second protrusion 17 on the back surface 11 is less than (1 / 3)L.

[0121] In this embodiment, the center of the orthographic projection of the second protrusion 17 on the back surface 11 is specifically the center of the projection of the second protrusion 17 along the thickness direction of the silicon substrate 1 on the back surface 11. By controlling the distance from the leakage tunneling layer 10 along the first direction X to the center of the orthographic projection of the second protrusion 17 on the back surface 11 to be less than (1 / 3)L, the leakage tunneling layer 10 is positioned as close as possible to the center of the second protrusion 17, which is more conducive to improving the heat dissipation effect of the second protrusion 17.

[0122] As an embodiment of the present invention, the leakage tunneling layer 10 is connected to the first dielectric layer 5 or the second dielectric layer 6, and the thickness of the leakage tunneling layer 10 is less than the thickness of at least one of the first dielectric layer 5 and the second dielectric layer 6.

[0123] In this embodiment, the leakage tunneling layer 10 can be integrally formed with the first dielectric layer 5 or with the second dielectric layer 6. Controlling the thickness of the leakage tunneling layer 10 to be less than the thickness of at least one of the first dielectric layer 5 and the second dielectric layer 6 is more conducive to the leakage tunneling layer 10 conducting the first extension 21 and the second extension 31 when the back contact solar cell 100 is shaded, thus improving the hot spot resistance performance of the back contact solar cell 100. The leakage tunneling layer 10 may be made of the same or different materials as the first dielectric layer 5 and the second dielectric layer 6. Preferably, the leakage tunneling layer 10 is a silicon oxide layer.

[0124] As an embodiment of the present invention, the projection of the first extension 21 along the thickness direction Z of the silicon substrate 1 covers at least a portion of the area of ​​the second extension 31, and an insulating layer 18 is provided between the second extension 31 and the first extension 21 along the thickness direction Z of the silicon substrate 1.

[0125] In this embodiment, the projection of the first extension 21 along the thickness direction Z of the silicon substrate 1 covers at least a portion of the second extension 31. Sunlight escaping from the location of the second extension 31 can be reflected back into the silicon substrate 1 by the first extension 21, which helps improve the utilization efficiency of sunlight. Simultaneously, an insulating layer 18 is provided between the second extension 31 and the first extension 21, ensuring that the second extension 31 and the first extension 21 can only be connected through the leakage tunneling layer 10. This ensures the reliability of the battery against hot spots and guarantees good power generation efficiency. For example, the insulating layer 18 can specifically be at least one of a silicon oxide layer, a silicon nitride layer, or a silicon oxynitride layer. The thickness of the insulating layer 18 is greater than the thickness of the leakage tunneling layer 10.

[0126] As an embodiment of the present invention, the surface of the second protrusion 17 is set as a polished surface.

[0127] In this embodiment, since the second extension 31 and the first extension 21 extend to the surface of the second protrusion 17, and the surface of the second protrusion 17 is set as a polished surface, it is beneficial to reduce the composite loss of the surface of the second protrusion 17 and to ensure good battery efficiency.

[0128] As an embodiment of the present invention, the protrusion height of the second protrusion 17 relative to the surface of the first region 111 is greater than the protrusion height of the first protrusion 16 relative to the surface of the first region 111; and / or, the protrusion height of the second protrusion 17 relative to the surface of the second region 112 is greater than the protrusion height of the first protrusion 16 relative to the surface of the second region 112.

[0129] In this embodiment, the second protrusion 17 may protrude only relative to the surface of the first region 111 or the surface of the second region 112, or the second protrusion 17 may protrude simultaneously relative to the surfaces of both the first region 111 and the second region 112. For example, Figure 11The surfaces of the first region 111 and the second region 112 are flush. The protrusion height of the second protrusion 17 relative to the surfaces of the first region 111 and the second region 112 is H7. The protrusion height of the first protrusion 16 relative to the surfaces of the first region 111 and the second region 112 is H6. H7 is greater than H6.

[0130] In this embodiment, when the second protrusion 17 protrudes relative to the surface of the first region 111, and the first protrusion 16 protrudes relative to the surface of the first region 111, the protrusion height of the second protrusion 17 relative to the surface of the first region 111 is greater than the protrusion height of the first protrusion 16 relative to the surface of the first region 111; for example, the ratio of the protrusion height of the second protrusion 17 relative to the surface of the first region 111 to the protrusion height of the first protrusion 16 relative to the surface of the first region 111 can be 1.1 to 2. When the second protrusion 17 protrudes relative to the surface of the second region 112, and the first protrusion 16 protrudes relative to the surface of the second region 112, the protrusion height of the second protrusion 17 relative to the surface of the second region 112 is greater than the protrusion height of the first protrusion 16 relative to the surface of the second region 112; for example, the ratio of the protrusion height of the second protrusion 17 relative to the surface of the second region 112 to the protrusion height of the first protrusion 16 relative to the surface of the second region 112 can be 1.1 to 2. This design increases the height of the second protrusion 17, which in turn increases its surface area, thereby improving the heat dissipation of the second protrusion 17 and enhancing the heat-spot resistance of the back-contact solar cell 100.

[0131] This invention also provides a battery assembly, which includes the back-contact solar cell 100 described in the above embodiments. It should be noted that this battery assembly has the same or similar beneficial effects as the back-contact solar cell 100, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0132] In this embodiment, multiple back-contact solar cells 100 in the battery module are connected in series by solder ribbons to form a battery string, thereby achieving series current collection and output.

[0133] It is understood that in such embodiments, the battery assembly may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front side 12 and back side 11 of the back-contact solar cell 100, the photovoltaic glass, adjacent cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0134] Photovoltaic glass can be applied to the encapsulant film on the front side 12 of the back-contact solar cell 100. The photovoltaic glass can be ultra-clear glass, which has high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, the light transmittance of ultra-clear glass can reach over 92%. It can protect the back-contact solar cell 100 while minimizing impact on its efficiency. Simultaneously, the encapsulant film bonds the photovoltaic glass and the back-contact solar cell 100 together, providing sealing, insulation, waterproofing, and moisture protection for the back-contact solar cell 100.

[0135] The backsheet can be attached to the adhesive film on the back side 11 of the back-contact solar cell 100. The backsheet provides protection and support for the back-contact solar cell 100, and has reliable insulation, water resistance, and aging resistance. Multiple options are available for the backsheet, typically tempered glass, acrylic glass, aluminum alloy TPT composite adhesive film, etc., and the specific choice depends on the specific circumstances and is not limited here. The backsheet, back-contact solar cell 100, adhesive film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.

[0136] This invention also provides a photovoltaic system, which includes the battery module described in the above embodiments. It should be noted that this photovoltaic system has the same or similar beneficial effects as the back-contact solar cell 100 described above, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0137] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0138] In the description of this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0139] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A back-contact solar cell, characterized in that, include: A silicon substrate, the silicon substrate including a back side and a front side disposed opposite to each other, the back side including a first region and a second region disposed alternately at intervals along a first direction, and an isolation region located between the first region and the second region; A first doped layer is disposed in the first region; and A second doped layer is provided in the second region, wherein the doping type of the second doped layer is opposite to that of the first doped layer; The silicon substrate forms at least one recess and at least one first protrusion in the isolation region. The recess is recessed relative to the surface of the first region and / or the surface of the second region, and the first protrusion is protruding relative to the surface of the first region and / or the surface of the second region. Both the recess and the first protrusion extend along a second direction, which intersects with the first direction.

2. The back-contact solar cell according to claim 1, characterized in that, The isolation area forms at least two recesses or at least two first protrusions, and the recesses and the first protrusions are alternately arranged along the first direction.

3. The back-contact solar cell according to claim 1, characterized in that, The isolation area forms two recesses and a first convexity, with a recess provided between the first region and the first convexity, and a recess provided between the second region and the first convexity.

4. The back-contact solar cell according to claim 1, characterized in that, The isolation area forms a recess and a first convex portion, the recess being located between the first region and the first convex portion, and the first convex portion being located between the recess and the second region; or, the recess being located between the second region and the first convex portion, and the first convex portion being located between the recess and the first region.

5. The back-contact solar cell according to claim 1, characterized in that, The protrusion height of the first protrusion relative to the surface of the first region and / or the surface of the second region is 3 to 40 micrometers.

6. The back-contact solar cell according to claim 1, characterized in that, The recessed depth of the recess relative to the surface of the first region and / or the surface of the second region is 1 to 10 micrometers.

7. The back-contact solar cell according to claim 1, characterized in that, The surface of the recess is provided with a first velvety structure.

8. The back-contact solar cell according to claim 7, characterized in that, The surface of the first protrusion is provided with a second velvety structure.

9. The back-contact solar cell according to claim 8, characterized in that, The distribution density of the second velvet structure is less than that of the first velvet structure.

10. The back-contact solar cell according to claim 1, characterized in that, A first region, a second region, and an isolation region constitute a repeating unit, and the ratio of the dimension of a single first protrusion along the first direction to the dimension of a single repeating unit along the first direction is 2% to 80%.

11. The back-contact solar cell according to claim 1, characterized in that, The ratio of the dimension of a single first protrusion along the first direction to the dimension of a single concave portion along the first direction is 0.1 to 20.

12. The back-contact solar cell according to claim 1, characterized in that, The size of a single isolation zone along the first direction is 50 to 600 micrometers.

13. The back-contact solar cell according to claim 1, characterized in that, The size of a single first protrusion along the first direction is 10 to 300 micrometers.

14. The back-contact solar cell according to claim 1, characterized in that, The size of a single recess along the first direction is 10 to 300 micrometers.

15. The back-contact solar cell according to claim 1, characterized in that, The first protrusion is continuously disposed in the second direction, and the dimension of the first protrusion along the second direction is the same as the dimension of the recess along the second direction.

16. The back-contact solar cell according to claim 1, characterized in that, The first protrusion is discontinuously arranged in the second direction, and the ratio of the dimension of the first protrusion along the second direction to the dimension of the concave portion along the second direction is greater than 90%.

17. The back-contact solar cell according to claim 8, characterized in that, The first protrusion includes a top surface disposed away from the front side along the thickness direction of the silicon substrate, and at least a portion of the top surface is provided with the second textured structure.

18. The back-contact solar cell according to claim 17, characterized in that, The first protrusion also includes two side surfaces disposed opposite to each other along the first direction, the two side surfaces being respectively connected to the top surface, and at least one side surface being provided with a textured structure.

19. The back-contact solar cell according to claim 17, characterized in that, The first convex portion is located between the concave portion and the first region, and the first doped layer extends to the top surface of the first convex portion; or, the first convex portion is located between the concave portion and the second region, and the second doped layer extends to the top surface of the first convex portion.

20. The back-contact solar cell according to claim 19, characterized in that, The top surface includes a textured area and a polished area, and the textured area is provided with a second textured structure; the first convex portion is located between the concave portion and the first area, and the first doped layer extends to the polished area; Alternatively, the first protrusion is located between the recess and the second region, and the second doped layer extends to the polished surface region.

21. The back-contact solar cell according to claim 1, characterized in that, The silicon substrate forms a second protrusion between partially adjacent first and second regions, the second protrusion protruding relative to the surface of the first region and / or the surface of the second region; A portion of the first doped layer includes a first extension extending onto the second protrusion, and a portion of the second doped layer includes a second extension extending onto the second protrusion, with a leakage tunneling layer disposed between the first extension and the second extension.

22. The back-contact solar cell according to claim 21, characterized in that, The second protrusion has a dimension of L along the first direction, and the distance from the leakage tunneling layer along the first direction to the center of the orthogonal projection of the second protrusion on the back side is less than (1 / 3)L.

23. The back-contact solar cell according to claim 21, characterized in that, Also includes: A first dielectric layer is disposed in the first region, located between the silicon substrate and the first doped layer; and The second dielectric layer is disposed in the second region and is located between the silicon substrate and the second doped layer.

24. The back-contact solar cell according to claim 23, characterized in that, The first dielectric layer and the second dielectric layer are respectively one or a combination of at least two of the following: silicon oxide layer, aluminum oxide layer, silicon carbide layer, silicon nitride layer, silicon oxynitride layer, and intrinsic amorphous silicon layer.

25. The back-contact solar cell according to claim 23, characterized in that, The leakage tunneling layer is connected to the first dielectric layer or the second dielectric layer, and the thickness of the leakage tunneling layer is less than the thickness of at least one of the first dielectric layer and the second dielectric layer.

26. The back-contact solar cell according to claim 21, characterized in that, The projection of the first extension along the thickness direction of the silicon substrate covers at least a portion of the second extension, and an insulating layer is provided between the second extension and the first extension along the thickness direction of the silicon substrate.

27. The back-contact solar cell according to claim 21, characterized in that, The surface of the second protrusion is set as a polished surface.

28. The back-contact solar cell according to claim 1, characterized in that, Also includes: A passivation layer that at least covers the first doped layer, the second doped layer, the recess, and the first protrusion.

29. The back-contact solar cell according to claim 1, characterized in that, Also includes: The first metal electrode is electrically connected to the first doped layer; and The second metal electrode is electrically connected to the second doped layer.

30. A battery assembly, characterized in that, Including the back-contact solar cell as described in any one of claims 1 to 29.

31. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 30.

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