Solar cell and photovoltaic module

Abstract

The invention provides a solar cell and a photovoltaic module, and belongs to the technical field of semiconductors. The solar cell comprises a cell body, the back face of the cell body is provided with a plurality of protruding structures extending in a linear mode, at least part of the protruding structures intersect with one another, and each protruding structure comprises a plurality of protruding parts arranged in a linear mode. According to the invention, the light utilization rate of the back surface is improved, so that the double-sided rate of the cell and the photovoltaic module is improved.

Description

Technical Field

[0001] This application relates to the technical field of solar cells, and particularly to a solar cell and a photovoltaic module. Background Art

[0002] Solar cells are one of the mainstream clean and renewable energy sources at present stage, with broad application prospects and development potential. Continuously improving the light-electricity conversion efficiency of solar cells and further reducing the cost per kilowatt-hour are the goals of scientific research and industrial manufacturing in this field. The efficiency loss of solar cells mainly comes from two major parts: optical loss and electrical loss. Therefore, it is necessary to continuously improve the light utilization rate and electrical conversion ability of the battery.

[0003] In the related art, since a large amount of direct sunlight is received on the front side of the battery, more attention is paid to the improvement of the front structure of the solar cell in terms of improving the light utilization rate of the solar cell. While the back side usually pursues a high flatness, and little consideration is given to the improvement of the light utilization rate during application. Summary of the Invention

[0004] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, this application provides a solar cell and a photovoltaic module.

[0005] In order to achieve the above object, the technical solution of this application is as follows:

[0006] According to an embodiment of one aspect of this application, a solar cell is provided, including: a battery body, the battery body includes a front side and a back side which are oppositely arranged, the back side has a plurality of convex structures extending linearly, at least some of the convex structures intersect with each other, and the convex structure includes a plurality of convex portions arranged linearly.

[0007] According to an embodiment of this application, the front side of the battery body does not have a convex structure extending linearly.

[0008] According to an embodiment of this application, the battery body includes a single crystal substrate of silicon or silicon germanium, and the convex structure extends along the direction of the intersection line of the (111) plane parallel to the single crystal substrate and the back side.

[0009] According to an embodiment of this application, the back side of the battery body includes a conductive region; wherein, the convex structure is distributed in a partial region of the conductive region close to the edge of the battery body.

[0010] According to an embodiment of this application, the edge of the battery body includes two opposite first sides and two opposite second sides, the conductive region includes: a plurality of first sub-regions, each extending along the direction parallel to the second side and spaced apart along the extending direction of the first side; wherein, taking at least one first sub-region close to the second side as a first edge sub-region, the convex structure is distributed in the first edge sub-region.

[0011] According to an embodiment of the present application, in the extending direction of the first side, the distribution width of the convex structure is less than or equal to the distribution width of the first edge sub-region.

[0012] According to an embodiment of the present application, multiple first sub-regions are alternately and spacedly distributed along the extending direction of the first side according to different conduction types; the back surface of the battery body further includes multiple spacer regions, which are located between two adjacent first sub-regions or between the first edge sub-region and the second side; wherein, the convex structure is not distributed in the spacer region, and / or, the convex structure is distributed in the first sub-region of at least one conduction type.

[0013] According to an embodiment of the present application, the second side is longer than the first side.

[0014] According to an embodiment of the present application, the conductive region further includes: multiple second sub-regions, each extending along a direction parallel to the first side and spacedly distributed along the extending direction of the second side; wherein, taking at least one second sub-region close to the first side as the second edge sub-region, the convex structure is distributed in the second edge sub-region; the number of second sub-regions located in the second edge sub-region is less than the number of first sub-regions located in the first edge sub-region.

[0015] According to an embodiment of the present application, the convex structures in the first sub-region close to one second side are staggered in the extending direction of the first side with the convex structures in the first sub-region close to the other second side; and / or, the included angle between the connection line of the ends of the convex structures in the first sub-region close to one second side and the ends of the convex structures in the first sub-region close to the other second side and the extending direction of the second side is not 45°.

[0016] According to an embodiment of the present application, the back surface of the battery body further has multiple concave structures, and the convex structure is distributed inside and / or outside the concave structure.

[0017] According to an embodiment of the present application, some of the concave structures are arranged linearly, and the included angle between the linear extending direction of the convex structure and the linear arrangement direction of the concave structure is 30° to 60°; and / or, the included angle between the linear extending direction of the convex structure and the edge of the battery body is 30° to 60°.

[0018] According to an embodiment of the present application, the one-dimensional size of the convex structure is less than the one-dimensional size of the concave structure; and / or, the height of the convex structure is less than 5 μm.

[0019] According to an embodiment of the present application, the back surface and / or the front surface of the battery body further has a pyramid structure, and the one-dimensional size of the convex structure is smaller than the one-dimensional size of the pyramid structure, wherein the pyramid structures and the convex structures on the back surface are respectively located in conductive regions of different conductive types on the back surface, or are respectively located in the spacer region and the conductive region on the back surface.

[0020] According to an embodiment of the present application, the battery body includes: a single-crystal substrate, a conductive region is provided on one side of the back surface of the single-crystal substrate; and a doped semiconductor layer, located in the conductive region; the solar cell further includes: an electrode, located on the doped semiconductor layer and in electrical contact with the doped semiconductor layer.

[0021] According to an embodiment of another aspect of the present application, a photovoltaic module is provided, including: a plurality of the above-mentioned solar cells connected in series to form a solar cell string; and an encapsulation layer covering the surface of the solar cell.

[0022] For the solar cell provided by the embodiment of the present application, by providing a plurality of convex structures extending linearly and intersecting with each other on the back surface of the battery body, the light trapping effect on the back surface of the solar cell can be improved without deteriorating the passivation effect, the light utilization rate can be enhanced, and thus the bifaciality of the battery can be increased.

[0023] For the photovoltaic module provided by the embodiment of the present application, based on the use of the above-mentioned solar cell, since the light utilization rate on the back surface is improved, at least the bifaciality of the battery can be increased, and further the bifaciality of the module can be increased. Description of the Drawings

[0024] Through the following description of the embodiments of the present application with reference to the drawings, the above and other objects, features and advantages of the present application will become clearer. In the drawings:

[0025] Figure 1 It is a light microscope image of the back surface of the battery body according to an embodiment of the present application;

[0026] Figure 2 is Figure 1 a light microscope image of the three-dimensional topography of the shown back surface;

[0027] Figure 3A It is a partial schematic diagram of the conductive region of the battery body according to an exemplary embodiment of the present application;

[0028] Figure 3B It is a partial schematic diagram of the conductive region of the battery body according to another exemplary embodiment of the present application;

[0029] Figure 3C It is a partial schematic diagram of the conductive region of the battery body according to still another exemplary embodiment of the present application;

[0030] Figure 4ASchematic diagram of the structure of a double-sided battery according to an exemplary embodiment of the present application;

[0031] Figure 4B Schematic diagram of the structure of a back-contact battery according to another embodiment of the present application.

[0032] In the above-mentioned drawings, the meanings of the reference numerals are as follows:

[0033] 1: Battery body;

[0034] 10: Monocrystalline silicon substrate;

[0035] 11: Protrusion structure, 12: First side, 13: Second side, 14: Depression structure;

[0036] 21: First doped semiconductor layer, 22: Second doped semiconductor layer;

[0037] 31: First passivation and antireflection layer, 32: Second passivation and antireflection layer;

[0038] 41: First interface passivation layer, 42: Second interface layer;

[0039] 51, First electrode, 52, Second electrode;

[0040] 1a: Back side;

[0041] A: Conductive region, A': Another conductive region, A1: First sub-region, A2: Second sub-region, B Spacing region. Detailed implementation manners

[0042] To make the objectives, technical solutions, and advantages of the present application clearer and more understandable, the following further details the present application in conjunction with specific embodiments and with reference to the accompanying drawings.

[0043] In the following detailed description, for the purpose of explanation, numerous specific details are set forth to provide a comprehensive understanding of the embodiments of the present application. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present application.

[0044] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "including" used herein indicates the presence of features, steps, operations, but does not exclude the presence or addition of one or more other features.

[0045] The relative position between two components (such as film layers or regions) mentioned in this application, such as "above", "upper" or "above", may refer to direct contact between the two components, or may refer to indirect contact between the two components. Similarly, the relative position between two components mentioned in this application, such as "below", "lower" or "below", may refer to direct contact between the two components, or may refer to indirect contact between the two components. For example, when one of the components (such as a film layer or region) is referred to as "on another component", it can be directly on the other component, or there may be other components between the two. On the other hand, when a component is referred to as "directly on another component", there is no component between the two. In addition, when one of the components is referred to as "on another component", the two have an up-and-down relationship in the top-view direction, and this component can be above or below the other component, so this up-and-down relationship depends on the orientation of the device.

[0046] In the relevant technologies of solar cells, since the front side of the solar cell is exposed to a large amount of direct sunlight, more attention is paid to the optimization of the front side structure to improve the light utilization rate, while the back side of the solar cell is more concerned with the improvement of its passivation and contact performance, especially the back contact cell, whose electrode structure is all transferred to the back side, which puts higher requirements on its passivation contact performance. Therefore, a higher flatness is usually used on the back side to facilitate the uniform deposition of the dielectric layer on the back side to ensure the passivation contact effect.

[0047] However, this also makes the optical performance of the back side of the solar cell worse than that of the front side. How to improve the light utilization rate on the back side and thus improve the cell efficiency and the bifaciality of the module is one of the important issues that need to be solved urgently, while the relevant technologies on how to improve the light utilization rate on the back side are relatively scarce.

[0048] In the process of realizing the concept of the present application, it was found that forming a linearly extending and mutually intersecting raised structure on the back of the solar cell can at least improve the light trapping effect on the back of the solar cell without deteriorating the passivation effect, thereby improving the light utilization rate of the solar cell, and further improving the cell efficiency and the bifaciality of the module.

[0049] Specifically, according to an embodiment of one aspect of the present application, a solar cell is provided, including a cell body. Figure 1 This is a light microscope image of the back side of the battery body of the embodiment of the present application. Figure 2 for Figure 1 The optical microscope image of the three-dimensional morphology of the back side is shown in Figure 1 and Figure 2 As shown, the back side 1a of the battery body 1 has a plurality of linearly extending protruding structures 11, and at least some of the protruding structures 11 intersect each other, wherein the protruding structures 11 include a plurality of linearly arranged protruding portions.

[0050] According to an embodiment of the present application, as Figure 2 shown, the convex portions included in the convex structure 11 may be pyramid-shaped, cone-shaped, frustum of a pyramid-shaped or frustum of a cone-shaped, without special limitation, as long as they can be arranged in a line.

[0051] According to an embodiment of the present application, the meaning of "linear" in the text means that on the one hand, the extending direction of the convex structure is a straight line or extends approximately in a straight line, and on the other hand, the extending length of the convex structure in the extending direction is much greater than its width in the direction perpendicular to its extending direction. For example, it can be at least greater than 20:1, 30:1, 40:1, 50:1, etc.

[0052] According to an embodiment of the present application, the battery body 1 of the present application may include a single crystal substrate of silicon or silicon germanium, and the convex structure 11 extends along the direction of the intersection line of the (111) plane parallel to the single crystal substrate and the back surface. The convex structure 11 of the present application may be formed on the single crystal substrate. By selecting a single crystal substrate of silicon or silicon germanium, it is more conducive to forming the convex structure 11. After depositing a film layer such as a doped semiconductor layer on the single crystal substrate to form the battery body, the convex structure 11 can still be observed.

[0053] According to an embodiment of the present application, the single crystal substrate of the present application may be an N-type, P-type or intrinsic single crystal substrate. The conversion efficiency of the battery based on a single crystal silicon substrate is relatively high compared to other types such as polycrystalline silicon batteries. Taking a single crystal silicon substrate as an example, by introducing donor impurities such as phosphorus (P), arsenic (As) or antimony (Sb) and other group VA elements into the single crystal silicon material, an N-type crystalline silicon substrate can be obtained, or by introducing acceptor impurities into these semiconductor materials, such as boron (B), aluminum (Al) or gallium (Ga) and other group IIIA elements, a P-type crystalline silicon substrate can be obtained.

[0054] According to an embodiment of the present application, the single crystal substrate of the present application has a specific crystal orientation. At a high temperature, for example, above 900 °C, especially above 950 °C and under certain gas pressure conditions, for example, for 2000 carrier wafers with a gas flow rate of 15 - 30 L / min, the preparation of the convex structure extending in a line is realized. After conformally depositing a film layer on the single crystal substrate to form the battery body, the convex structure 11 is also formed on the back surface 1a of the battery body 1. That is to say, it is not limited to the type of battery. As long as under the above process conditions, it is easy to form the convex structure 11 on the single crystal substrate, and it is easier to form specifically at the position where the single crystal substrate contacts the carrying tooling. By arranging a plurality of convex structures 11 extending in a line and intersecting with each other on the back surface 1a of the battery body 1, this linear distribution structure can improve the light utilization rate and the bifaciality of the battery without deteriorating the passivation effect.

[0055] According to an embodiment of the present application, the half-cell is more affected by the above process conditions and has more convex structures 11, while the whole-cell is less affected by the above process conditions and has relatively fewer convex structures.

[0056] According to an embodiment of the present application, the front surface (not shown in the figure) of the battery body 1 is generally the surface that can directly receive direct sunlight and serves as the light-receiving surface; the back surface 1a is opposite to the front surface and generally does not directly receive direct sunlight and serves as the backlight surface, but it is not limited thereto, and it can also be double-sided light-receiving. For example, the back surface can receive direct sunlight in different application scenarios, or can receive reflected light from surfaces such as the ground or the roof surface, then both the front surface and the back surface serve as the light-receiving surfaces.

[0057] Optionally, the front surface of the battery body 1 can have a pyramid structure to improve the light-trapping effect of the front surface. Further optionally, the front surface of the battery body 1 opposite to the back surface 1a does not have the convex structure 11 extending linearly. Thus, since the front surface of the battery body 1 generally needs to form a pyramid texture to improve the light-trapping effect, if convex structures are formed on both the back surface and the front surface, it will increase the thinning amount of the battery body and increase the risk of battery cracking.

[0058] According to an embodiment of the present application, the back surface and the front surface of the battery body 1 can generally be (100) crystal planes to obtain good carrier transport effects.

[0059] According to an embodiment of the present application, the back surface 1a of the battery body 1 includes a conductive region, and the convex structures 11 are distributed in a partial region of the conductive region close to the edge of the battery body 1. The "conductive region" here is a region suitable for selectively transporting carriers such as electrons or holes, and the conductive region A can be located inside or on the back surface of the single crystal substrate. Exemplarily, the conductive region can include a doped semiconductor layer formed by in-diffusion doping of the single crystal substrate, or can include a doped semiconductor layer deposited on the single crystal substrate.

[0060] According to an embodiment of the present application, the conductive region A can be located in the entire region or a partial region of the back surface 1a of the battery body 1. In an alternative embodiment, the back surface 1a of the battery body 1 includes a conductive region A, which can be an N region or a P region. It can be understood that the N region is suitable for selectively transporting and collecting electrons, and the P region is suitable for selectively transporting and collecting holes. The conductive region A is disposed entirely on the back surface. At this time, the solar cell can be a double-sided cell, and the convex structures 11 can be distributed in a partial region of the conductive region A close to the edge of the battery body 1, but it can be understood that the convex structures 11 can also be distributed in the entire region of the conductive region A.

[0061] Figure 3A It is a partial schematic diagram of the conductive region of the battery body according to an exemplary embodiment of the present application, which simplifies and shows the local distribution of the convex structures 11 in the conductive region A. AsFigure 3A As shown, the conductive region A can be disposed entirely on the back surface 1a, and the convex structures 11 can be distributed in a partial region of the conductive region A near the edge of the battery body 1. Exemplarily, as Figure 3A shown, the battery body 1 includes two opposite first sides 12 and two opposite second sides 13, and the convex structures 11 can be distributed in a partial region of the conductive region A near the first side 12 and the second side 13. However, it is not limited thereto, and can also be distributed in a partial region of the conductive region A only near the first side or only near the second side 13.

[0062] In this way, when the convex structures 11 are located in the conductive region A, it is beneficial to increase the light trapping effect of the conductive region, thereby increasing the current. On this basis, due to the uneven distribution of the film thickness on the silicon substrate at the battery edge and the battery center, for example, the film layers located at the battery edge, such as the doped semiconductor layer and / or the passivation and antireflection layer, etc., have a thicker thickness compared to the corresponding film layers located at the battery edge, resulting in the battery center generally having a higher light utilization rate and electrical contact performance than the battery edge. Therefore, by distributing the convex structures in the region near the edge of the battery body, it is more beneficial to improve the light trapping effect of the battery edge region and improve the optical loss at the battery edge.

[0063] According to an embodiment of the present application, as Figure 3A shown, in the extending direction S1 of the first side 12, the convex structures 11 are continuously and penetratingly distributed in the conductive region A; however, it is not limited thereto, and the convex structures 11 can also be discontinuously distributed in a partial region of the conductive region A. The distribution of the convex structures 11 in the extending direction S2 of the second side 13 can also be distributed in this way, which will not be elaborated herein.

[0064] In this way, since the convex structures 11 macroscopically show the deformation of the battery body, the larger the proportion of the deformed region, the greater the risk of cracking of the battery body. Therefore, by controlling the distribution of the convex structures 11 in a partial region of the conductive region A, it is more beneficial to reduce the risk of cracking of the battery body.

[0065] According to an embodiment of the present application, as Figure 3AAs shown, in the case where the convex structure 11 is distributed in the area of the back surface 1a near the first side 12, the distribution width L1 of the convex structure 11 in the extending direction S2 of the second side 13 is less than or equal to 1 cm. For example, it can be 0.05 cm, 0.1 cm, 0.15 cm, 0.2 cm, 0.3 cm, 0.4 cm, 0.5 cm, 0.55 cm, 0.6 cm, 0.7 cm, 0.8 cm, 0.9 cm, 1 cm, etc. Similarly, in the case where the convex structure is distributed in the area of the back surface 1a near the second side 13, there is a similar distribution for the distribution width of the convex structure 11 in the extending direction S1 of the first side 12. Here, the "distribution width" refers to the width of the area where the target object such as the convex structure is distributed, and the area where the target object is not distributed is not included.

[0066] In another alternative embodiment, the back surface 1a of the battery body 1 includes a conductive region A, which can be an N region and / or a P region, and the conductive region A is provided in a partial area of the back surface 1a. At this time, the solar cell can be a back-contact cell or a bifacial cell, and the convex structure can be distributed in a partial area near the edge of the battery body 1 in the conductive region A. However, it can be understood that the convex structure 11 can also be distributed in the entire region of the conductive region A.

[0067] Exemplarily, Figure 3B is a partial schematic diagram of the conductive region of the battery body according to another exemplary embodiment of the present application. As Figure 3B shown, the conductive region A includes a plurality of first sub-regions A1, each extending in a direction parallel to the second side 13 and spaced apart in the extending direction of the first side 12; among them, at least one first sub-region A1 close to the second side 13 is used as the first edge sub-region, and the convex structure 11 is distributed in the first edge sub-region.

[0068] At this time, the conductive types of the plurality of first sub-regions A1 can be the same, both being N regions or both being P regions, then the solar cell can be a bifacial cell; or, the plurality of first sub-regions A1 are alternately spaced in the extending direction of the first side 12 according to different conductive types, then the solar cell can be a back-contact cell.

[0069] Exemplarily, as Figure 3B shown, the convex structure 11 is distributed in 1 first sub-region A1 close to the second side 13, but it is not limited thereto, and it can also be, but not limited to, for example, 2, 3, 4, 5, 6, 7 first sub-regions A1, etc. close to the second side 13, and these first sub-regions A1 constitute the first edge sub-region. It can be understood that the convex structure 11 can also be distributed in the entire region of the conductive region A. In this way, distributing the convex structure in the area near the edge of the battery body is more conducive to improving the light trapping effect in the edge area of the battery and improving the optical loss at the edge of the battery.

[0070] According to an embodiment of the present application, in the extending direction of the first side 12, the distribution width of the convex structure 11 is less than or equal to the distribution width of the first edge sub-region. Exemplarily, as Figure 3B shown, at a position close to the upper second side 13, the distribution width L1 of the convex structure may be equal to the distribution width L2 of the first edge conductive region, and at a position close to the lower second side 13, the distribution width L1 of the convex structure may be less than the distribution width L2 of the first edge conductive region. Thus, it is beneficial to reduce the risk of cracking of the battery body 1.

[0071] According to an embodiment of the present application, as Figure 3B shown, in the extending direction S2 of the second side 13, the convex structure 11 is discontinuously distributed in the first edge conductive region. However, it is not limited thereto, and the convex structure 11 may also be continuously and penetratingly distributed in the first edge conductive region. Thus, by regulating the local region of the convex structure 11 distributed in the conductive region A, it is more beneficial to reduce the risk of cracking of the battery body.

[0072] It should be noted that at positions close to the two opposite second sides 13, the distributions of the convex structures may be the same or different. For example, the distribution widths of the convex structure 11 in the extending direction S1 of the first side 12 may be the same or different, or the distribution continuities of the convex structure 11 in the extending direction S2 of the second side 13 may be the same or different.

[0073] According to an embodiment of the present application, in the extending direction S1 of the first side 12, within a first sub-region A1, the ratio range between the distribution width L1 of the convex structure 11 and the distribution width of this first sub-region is greater than 0 and less than or equal to 1, and further preferably ranges from 1:5 to 1:1. For example, it may be 1:5, 1 / 3, 2:5, 3:5, 2 / 3, 4:5, 1:1, etc. It can be understood that when L1 / L2 = 1:1, it means that the convex structure 11 is continuously and penetratingly distributed in the first sub-region A1 in the extending direction S1 of the first side 12. Exemplarily, in the extending direction of the first side 12, within a first sub-region A1, the distribution width of the convex structure 11 may be less than 50 μm. For example, it may be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, etc.

[0074] According to an embodiment of the present application, taking the other first sub-regions except the first edge sub-region among the multiple first sub-regions A1 as the first non-edge sub-regions, the convex structure 11 may also be distributed in partial regions (not shown in the figure) of the first non-edge sub-regions close to the first side 12.

[0075] According to an embodiment of the present application, in the case where the solar cell is a back contact battery, as Figure 3BAs shown, a plurality of first sub-regions A1 are alternately and spacedly distributed along the extending direction S1 of the first side 12 according to different conduction types; the back surface of the battery body further includes a plurality of spacer regions B, which are located between two adjacent first sub-regions A1 or between the first edge sub-region and the second side 13; wherein, the protruding structure 11 is not distributed in the spacer region B. Electrical isolation can be achieved by etching the spacer region located between adjacent first sub-regions A1, so as to etch away the protruding structure 11 located in the spacer region B. According to an embodiment of the present application, when the solar cell is a back-contact battery, as Figure 3B As shown, a plurality of first sub-regions A1 are alternately and spacedly distributed along the extending direction S1 of the first side 12 according to different conduction types; wherein, the protruding structure 11 is distributed in at least one conduction type of the first sub-regions A1, that is, distributed in the first sub-regions A1 of the first conduction type and / or the second conduction type.

[0076] Among them, taking the HPBC battery (Hybrid Passivated Back Contact) or the hybrid BC battery as an example, the protruding structure 11 can be only distributed in the first sub-region A1 of the first conduction type with a topcon structure, such as the N region of the HPBC battery or the hybrid BC battery. At this time, the first sub-region A1 of the first conduction type can include a doped polysilicon layer deposited on a single-crystal substrate as a doped semiconductor layer, while the first sub-region A1 of the second conduction type can be a doped semiconductor layer obtained by doping the single-crystal substrate with an aluminum electrode, or a doped amorphous silicon obtained by a low-temperature process as a doped semiconductor layer.

[0077] Taking the TBC (TopCon-Back Contact) battery as an example again, the protruding structure 11 can be distributed in the first sub-regions A1 of both the first conduction type and the second conduction type at the same time. At this time, the first sub-regions A1 of the first conduction type and the second conduction type can respectively include a doped polysilicon layer deposited on a single-crystal substrate as a doped semiconductor layer. And the protruding structure in the P region is more than that in the N region, which is convenient for improving the power generation efficiency of the emitter region.

[0078] It can also be understood that it is not limited to the back-contact battery. When the solar cell is a bifacial battery, as Figure 3B As shown, the protruding structure 11 is distributed in the first sub-region A1 of one conduction type, such as on the side of the P-type doped region. At this time, the conductive region can include a P-type doped region located in the single-crystal substrate as a doped semiconductor layer.

[0079] Further optionally, the protruding structure can be distributed in the first edge sub-region of the N type, or in the first edge sub-region of the P type, or distributed in the first edge sub-regions of both the N type and the P type at the same time.

[0080] It should be noted that Figure 3A and Figure 3B merely for illustration, the protruding structure 11 extends in a continuous ground line shape within a conductive region to form a rectangular distribution network. According to Figure 1 and Figure 2 the protruding structure 11 shown, it is not limited thereto. It can actually extend in a continuous and / or discontinuous ground line shape to form a distribution network in a regular or irregular shape such as a rectangle or a circle.

[0081] Moreover, for a double-sided battery or a back-contact battery, although Figure 3A it is shown that the protruding structure 11 is distributed in the region near a first side 12 and the region near a second side 13 of the back surface 1a, Figure 3B it is shown that the protruding structure 11 is distributed in the region near a second side 13 of the back surface 1a. However, it can be understood that it is not limited thereto. The protruding structure 11 can be distributed in the region near one side, two sides, three sides, or four sides of the back surface 1a.

[0082] According to an embodiment of the present application, optionally, the second side 13 is longer than the first side 12. Thus, the protruding structure 11 is at least partially distributed in the region near the longer side of the first side 12 and the second side 13. In this way, it is beneficial to increase the occupied area of the protruding structure 11 and improve the light trapping effect. In particular, for a back-contact battery, the first sub-region extending along the longer side can be a junction region, and the protruding structure 11 is at least distributed in the junction region, which is beneficial to generate and separate photo-generated carriers, increase the concentration of photo-generated carriers, and further increase the current.

[0083] According to an embodiment of the present application, Figure 3C is a partial schematic view of the conductive region of the battery body of another exemplary embodiment of the present application. As Figure 3C shown, the conductive region A further includes: a plurality of second sub-regions A2, each extending along a direction parallel to the first side and spaced apart along the extension direction of the second side. In the case where the solar cell is a back-contact battery, the second sub-region A2 is electrically connected to the first sub-region A1 of the same conductivity type and electrically isolated from the first sub-region A1 of a different conductivity type.

[0084] For the convenience of description and understanding, only 2 second sub-regions A2 are shown in the figure. It can be understood that it is not limited thereto and there can be more second sub-regions A2, which can be specifically set according to actual situations. Among them, at least one second sub-region A2 near the first side 12 is used as a second edge sub-region, and the protruding structure is distributed in the second edge sub-region; the number of second sub-regions A2 located in the second edge sub-region is less than the number of first sub-regions A1 located in the first edge sub-region.

[0085] At this time, the first sub-region A1 can serve as a current collecting region, that is, the main region for current collection, and the second sub-region A2 can serve as a current collecting region, mainly for collecting current. The protrusion structures 11 are more distributed in the current collecting region, which is more conducive to increasing the concentration of photo-generated carriers in the current collecting region, thereby more effectively improving the current collection efficiency.

[0086] According to an embodiment of the present application, further optionally, the protrusion structures 11 in the first sub-region A1 near one second side 13 and the protrusion structures 11 in the first sub-region A1 near the other second side 13 are staggered in the extension direction S1 of the first side 12, that is, non-aligned. In this way, it is possible to avoid corresponding deformation regions at the longer sides of the battery body 1, thereby reducing the risk of cracking of the battery body 1 in subsequent battery processes.

[0087] Further optionally, the angle between the line connecting the ends of the protrusion structures 11 in the first sub-region near one second side 13 and the line connecting the ends of the protrusion structures 11 in the first sub-region near the other second side 13 and the extension direction of the second side 13 is not 45°. This is because when the angle between the line connecting the protrusion structures 11 and the extension direction S2 of the second side is 45°, the line is parallel to the cleavage plane direction of the single crystal substrate, which makes it easy for the battery body 1 to crack when welding the joint (or the pad) of the battery in the direction parallel to the first side.

[0088] According to an embodiment of the present application, for another example Figure 1 and Figure 2 As shown, the back surface 1a of the battery body 1 further has a plurality of concave structures 14, and the protrusion structures 11 are distributed inside and / or outside the concave structures 14. The combination of the protrusion structures 11 and the concave structures 14 is more conducive to improving the light trapping effect on the back surface of the battery.

[0089] Further optionally, the concave structure 14 can be, for example, a tower base structure or other structures, and specifically can include a plurality of concave portions recessed into the interior of the battery body 1. The concave portions can be in the shape of a frustum of a pyramid, a frustum of a cone, etc.

[0090] According to an embodiment of the present application, for another example Figure 1As shown, the partial concave structures 14 are arranged linearly. At this time, the included angle between the linear extension direction of the convex structure 11, that is, the (111) crystal plane extension direction of the single crystal substrate, and the linear arrangement direction of the concave structures is 30° to 60°, for example, it can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, etc.; and / or, the included angle between the linear extension direction of the convex structure 11 and the edge of the battery body 1 is 30° to 60°, for example, it can be 30°, 35°, 40°, 45°, 50°, 55°, 60°, etc. In this way, an acute angle is formed between the extension direction of the convex structure 11 and the arrangement direction of the concave structures 14, which can avoid the convex structure from affecting the formation quality of the electrode.

[0091] According to an embodiment of the present application, the one-dimensional size of the convex structure 11 is smaller than the one-dimensional size of the concave structure 14; the one-dimensional size includes, for example, height, bottom width, diameter, etc.

[0092] Exemplarily, the ratio of the height of the convex structure 11 to the height of the concave structure 14 is 1:15 to 1:45, for example, it can be 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, etc. Further optionally, the height of the convex structure 11 is less than 5 μm, for example, it can be 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, etc.

[0093] Exemplarily, the ratio of the bottom width of the convex structure 11 to the bottom width of the concave structure 14 is 1:10 to 1:20, for example, it can be 1:10, 1:12, 1:14, 1:16, 1:18, 1:20, etc.

[0094] According to an embodiment of the present application, there is no limitation on the size measurement of the convex structure 11 and the concave structure 14. Those skilled in the art can measure them by conventional methods in the art. For example, the bottom width or height of the convex structure 11 and the concave structure 14 can be measured by an optical microscope. Specifically, the bottom width or height of the two is sampled and measured in the light microscope image of the battery body, and then the average value is taken.

[0095] With such a setting, by controlling the size of the convex structure within a moderate range, it is beneficial to improve the quality of the doped semiconductor layer deposited on the back surface 1a of the battery body 1, thereby improving the passivation effect, and it is also beneficial to increase the contact specific surface area between the battery body and the electrode and reduce the contact resistance between the doped semiconductor layer and the electrode.

[0096] According to an embodiment of the present application, the solar cell can be a bifacial cell or a back contact cell. At this time, the back surface 1a of the cell body 1 can include a single crystal substrate and a doped semiconductor layer. A conductive region A is provided on one side of the back surface of the single crystal substrate, and the doped semiconductor layer is located within the conductive region; the solar cell can further include an electrode, which is located on the doped semiconductor layer and is in electrical contact with the doped semiconductor layer. Thus, based on the convex structure of the conductive region A, the doped semiconductor layer can still be conformally deposited on the single crystal substrate with relatively high quality, ensuring the passivation effect and improving the light trapping effect at the edge of the cell body, thereby improving the cell efficiency.

[0097] For ease of understanding, Figure 4A FIG. is a schematic structural diagram of a bifacial cell according to an exemplary embodiment of the present application. As Figure 4A shown, taking the bifacial cell as an example, the back surface 1a of the cell body 1 includes a conductive region A, which can be, for example, an N region or a P region, covering the entire back surface 1a. At this time, the distribution of the convex structure 11 on the back surface 1a is similar to that in the foregoing embodiment and will not be elaborated herein.

[0098] The cell body 1 can specifically include a single crystal silicon substrate 10 and a first doped semiconductor layer 21. A conductive region A is provided on one side of the back surface of the single crystal silicon substrate 10, and the first doped semiconductor layer 21 is located within the conductive region A. The solar cell can further include a first electrode 51. The first doped semiconductor layer 21 is located within or on the surface of the single crystal silicon substrate 10, and its material can be, for example, at least one of single crystal silicon, polycrystalline silicon, and microcrystalline silicon. The first electrode 51 is located on the first doped semiconductor layer 21 and is in electrical contact with the first doped semiconductor layer 21.

[0099] Exemplarily, the first doped semiconductor layer 21 can be a doped layer formed by phosphorus diffusion or boron diffusion process within the surface of the single crystal silicon substrate 10, or a doped polycrystalline silicon or microcrystalline silicon layer obtained by depositing an amorphous silicon layer on the surface of the single crystal silicon substrate 10 by low temperature chemical vapor deposition (LPCVD) and then doping through phosphorus diffusion or boron diffusion process.

[0100] It should be noted that in the case where the first doped semiconductor layer 21 is formed by thermal diffusion, the process including high temperature and gas pressure conditions for preparing the convex structure can be carried out synchronously with the phosphorus diffusion or boron diffusion process, thereby simplifying the preparation process; of course, it is not limited thereto, and the convex structure can also be prepared first, and then the first doped semiconductor layer 21 is formed.

[0101] According to an embodiment of the present application, the cell body 1 can further include a first passivation and antireflection layer 31, which is located on the surface of the first doped semiconductor layer 21 away from the single crystal substrate 1, and functions to protect and passivate the doped semiconductor layer and reduce the reflection of light incident on the back surface. The first electrode 51 passes through the first passivation and antireflection layer 31 to contact the first doped semiconductor layer 21.

[0102] Exemplarily, the first passivation and antireflection layer 31 can be a single-layer film formed of silicon dioxide, aluminum oxide, silicon nitride, or silicon oxynitride, or a stacked film formed by combining one or more of the foregoing materials. Further optionally, it can be a stacked structure of aluminum oxide and silicon nitride provided on the side of the aluminum oxide layer facing away from the single-crystalline silicon substrate, or a stacked structure of aluminum oxide, silicon nitride, and silicon oxynitride provided on the side of the aluminum oxide layer facing away from the single-crystalline silicon substrate.

[0103] According to an embodiment of the present application, the front surface 1b of the battery body 1 opposite to the back surface 1a includes another conductive region A', that is, another conductive region A' is provided on the front side of the single-crystalline silicon substrate 10. The battery body 1 may further include a second doped semiconductor layer 22 and a second passivation and antireflection layer 32. Among them, the second doped semiconductor layer 22 is located within another conductive region A', and the second passivation and antireflection layer 32 is located on the surface of the second doped semiconductor layer 22 away from the single-crystalline silicon substrate 10. The material of the second doped semiconductor layer is similar to that of the first doped semiconductor layer, and the material of the second passivation and antireflection layer 32 is similar to that of the first passivation and antireflection layer 31, so details will not be described again.

[0104] According to an embodiment of the present application, the solar cell may further include a second electrode 52, which passes through the second passivation and antireflection layer 32 to be in electrical contact with the second doped semiconductor layer 22.

[0105] According to an embodiment of the present application, the solar cell may further include an interface passivation layer (not shown in the figure). The interface passivation layer may be located between the first doped semiconductor layer 21 and the battery body 1, and is used to selectively pass majority carriers and achieve a field passivation effect, improving the carrier separation and collection effect.

[0106] Exemplarily, taking the first doped semiconductor layer 21 as a doped polysilicon or microcrystalline silicon layer as an example, the first interface passivation layer can be an oxide dielectric layer, which forms a tunneling passivation contact structure with the first doped semiconductor layer 21. Exemplarily, the oxide dielectric layer can be aluminum oxide, silicon oxide, titanium oxide, amorphous silicon, etc., and can be prepared by low-temperature chemical vapor deposition (LPCVD); optionally, the thickness of the oxide dielectric layer can be 0.5 - 10 nm. The corresponding solar cell can be a TOPCon (Tunnel Oxide Passivating Contacts) cell at this time.

[0107] Figure 4B Schematic structural diagram of a back-contact battery according to another embodiment of the present application, as Figure 4BAs shown, taking the back-contact battery as an example, the main difference from the above-mentioned bifacial battery lies in that the conductive region A includes a plurality of first sub-regions A1, which are alternately and spacedly distributed on the back surface 1a according to the N-type and P-type conductive types. At this time, the protruding structure 11 can be distributed in the first sub-regions A1 of both the N-type and P-type. The specific distribution method is similar to that of the foregoing embodiments and will not be elaborated herein.

[0108] The solar cell may further include a first doped semiconductor layer 21 and a second doped semiconductor layer 22. Exemplarily, the first doped semiconductor layer 21 may be located in the first sub-region A1 of the first conductive type, and the second doped semiconductor layer 22 may be located in the first sub-region A1 of the second conductive type. One of the first conductive type and the second conductive type is N-type, and the other is P-type.

[0109] The materials or structures of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 are similar to the above. Exemplarily, taking Figure 4B the shown example, they may be doped polysilicon or microcrystalline silicon layers deposited on the single-crystal silicon substrate 10 by low-temperature chemical vapor deposition (LPCVD) and diffusion processes respectively. Of course, it is not limited thereto, and it may also be a doped layer formed in the surface of the single-crystal silicon substrate 10 by phosphorus diffusion or boron diffusion processes.

[0110] Further optionally, the solar cell may further include a first interface passivation layer 41 and a second interface passivation layer 42. The two may be oxidation dielectric layers respectively. At this time, the first interface passivation layer 41 may be located between the first doped semiconductor layer 21 and the single-crystal silicon substrate 10, forming a tunneling passivation contact structure with the first doped semiconductor layer 21, and the second interface passivation layer 42 may be located between the second doped semiconductor layer 22 and the single-crystal silicon substrate 10, forming a tunneling passivation contact structure with the second doped semiconductor layer 22. At this time, the corresponding solar cell is a TBC (TopCon-Back Contact, tunneling oxidation passivation back contact) battery.

[0111] Of course, it is not limited to this. The solar cell of the present application can also be other battery types, such as IBC cells (Interdigitated back-contact cells), HPBC cells (Hybrid Passivated Back Contact), hybrid BC cells, etc. Taking the HPBC cell as an example, the main difference from the above-mentioned TBC cell is that the second doped semiconductor layer 22 can be a doped semiconductor layer formed by doping a single-crystalline silicon substrate 10 with an aluminum electrode and is located within the surface of the single-crystalline silicon substrate 10. Taking the hybrid BC cell as an example, the main difference from the above-mentioned TBC cell is that the second doped semiconductor layer 22 can be a doped amorphous silicon layer, and the second interface passivation layer 41 can be an amorphous silicon layer. At this time, the second interface passivation layer 41 and the second doped semiconductor layer 22 can be used to form a heterojunction contact structure. At this time, the protruding structure 11 can be separately distributed within the first sub-region of the first conductivity type.

[0112] According to an embodiment of the present application, the solar cell includes:

[0113] A single-crystalline substrate, on one side of the back surface of the single-crystalline substrate, there is a conductive region;

[0114] A doped semiconductor layer, located within the conductive region;

[0115] An electrode, located on the doped semiconductor layer and in electrical contact with the doped semiconductor layer; wherein,

[0116] The thickness or thickness uniformity of the film layer on the protruding structure 11 formed on the single-crystalline substrate of the doped semiconductor layer is thinner or worse than that of the film layer on the corresponding non-protruding structure, but the thickness of the film layer on the protruding structure corresponding to the doped semiconductor layer cannot be lower than 50 nm, and the thickness uniformity cannot be lower than 80%, otherwise the passivation contact function cannot be achieved. For example, doped polysilicon is used as the doped semiconductor layer in this embodiment.

[0117] Optionally, the solar cell further includes an interface passivation layer. The interface passivation layer is located between the single-crystalline substrate and the doped semiconductor layer. The thickness or thickness uniformity of the film layer on the protruding structure corresponding to the interface passivation layer is thinner or worse than that of the film layer on the corresponding non-protruding structure, but the thickness of the film layer on the protruding structure corresponding to the interface passivation layer cannot be lower than 0.5 nm, and the thickness uniformity cannot be lower than 70%, otherwise the interface passivation function cannot be achieved. For example, silicon oxide is used as the interface passivation layer in this embodiment.

[0118] Optionally, the solar cell further includes a passivation layer and / or an antireflection layer. The passivation layer and / or the antireflection layer is located on the doped semiconductor layer. The thickness or thickness uniformity of the film layer on the corresponding raised structure of the passivation layer and / or the antireflection layer is thinner or worse than that of the film layer on the corresponding non-raised structure. However, the thickness of the film layer on the corresponding raised structure of the passivation layer and / or the antireflection layer cannot be lower than 40 nm, and the thickness uniformity cannot be lower than 75%, otherwise the antireflection function cannot be achieved. For example, in this embodiment, the stack of alumina and silicon nitride is used as the passivation and antireflection layer.

[0119] According to an embodiment of another aspect of the present application, a photovoltaic module is provided, including: a plurality of the above-mentioned solar cells connected in series to form a solar cell string; and a packaging layer covering the surface of the solar cells.

[0120] According to the embodiment of the present application, the number of series-connected solar cells can be 4 to 80, for example, it can be 4, 24, 54, 72, 78, etc. A plurality of solar cells can form several solar cell strings. Each solar cell string has the same number of solar cells. The cells in the solar cell string are connected in series. The solar cell strings can be connected in series or in parallel, and the solar cell strings are connected by busbars. The distance between two adjacent solar cell strings can be 0.5 to 10 mm, for example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.; the distance between two adjacent cells in each solar cell string can be 0.5 to 10 mm, for example, it can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.

[0121] According to the embodiment of the present application, the packaging layer can include a backsheet, an encapsulant film, a glass panel, etc., to improve the stability of the solar cell string. Among them, the glass panel is located on the front of the solar cell string, and the backsheet is located on the back of the solar cell string, both of which play a protective role; the adhesive encapsulant film is the adhesive film between the solar cell string and the glass panel and the backsheet, which plays an adhesive and fixing role and must be made of a transparent material.

[0122] The above specific embodiments further elaborate on the purpose, technical solutions, and beneficial effects of the present application. It should be understood that the above are only specific embodiments of the present application and are not used to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A solar cell, comprising: A cell body, the cell body including a front side and a back side arranged opposite to each other, the back side having a plurality of raised structures extending linearly, at least some of the raised structures intersecting each other, and the raised structures including a plurality of raised portions arranged linearly.

2. The solar cell according to claim 1, wherein The front side does not have a raised structure extending linearly.

3. The solar cell according to claim 1, wherein, The cell body includes a single crystal substrate of silicon or silicon germanium, and the raised structures extend along a direction parallel to the intersection line of the (111) plane of the single crystal substrate and the back side.

4. The solar cell according to claim 1, wherein, The back side includes a conductive region; Wherein, the raised structures are distributed in a partial region of the conductive region close to the edge of the cell body.

5. The solar cell according to claim 4, wherein The edge of the cell body includes two opposite first sides and two opposite second sides, and the conductive region includes: A plurality of first sub-regions, each extending along a direction parallel to the second side and spaced apart along the extending direction of the first side; Wherein, taking at least one first sub-region close to the second side as a first edge sub-region, the raised structures are distributed within the first edge sub-region.

6. The solar cell according to claim 5, wherein In the extending direction of the first side, the distribution width of the raised structures is less than or equal to the distribution width of the first edge sub-region.

7. The solar cell according to claim 5, wherein, The plurality of first sub-regions are alternately and spaced apart along the extending direction of the first side according to different conductive types; The back side of the cell body further includes a plurality of spacer regions, located between two adjacent first sub-regions or between the first edge sub-region and the second side; wherein, the raised structures are not distributed in the spacer regions, and / or, the raised structures are distributed in the first sub-regions of at least one conductive type.

8. The solar cell according to claim 5, wherein, The second side is longer than the first side.

9. The solar cell according to claim 8, wherein, The conductive region further includes: a plurality of second sub-regions, each extending along a direction parallel to the first side and spaced apart along the extending direction of the second side; Wherein, taking at least one second sub-region close to the first side as a second edge sub-region, the raised structures are distributed within the second edge sub-region; the number of second sub-regions within the second edge sub-region is less than the number of first sub-regions within the first edge sub-region.

10. The solar cell according to claim 8, wherein: The raised structures within the first sub-region close to one second side are staggered in the extending direction of the first side from the raised structures within the first sub-region close to the other second side; and / or, the included angle between the connection line of the ends of the raised structures within the first sub-region close to one second side and the ends of the raised structures within the first sub-region close to the other second side and the extending direction of the second side is not 45°.

11. The solar cell according to claim 1, wherein, The back side of the cell body further has a plurality of recessed structures, and the raised structures are distributed within and / or outside the recessed structures.

12. The solar cell according to claim 11, wherein: Some of the recessed structures are arranged linearly, and the included angle between the linear extending direction of the raised structures and the linear arrangement direction of the recessed structures is 30 to 60°; And / or, the included angle between the linear extension direction of the convex structure and the edge of the battery body is 30° to 60°.

13. The solar cell according to claim 11, wherein, The one-dimensional size of the convex structure is smaller than the one-dimensional size of the concave structure; and / or, the height of the convex structure is less than 5 μm; And / or, the back surface and / or the front surface of the battery body further has a pyramid structure, and the one-dimensional size of the convex structure is smaller than the one-dimensional size of the pyramid structure, wherein the pyramid structure on the back surface and the convex structure are respectively located in conductive regions of different conductive types on the back surface, or are respectively located in the spaced region and the conductive region on the back surface.

14. The solar cell according to claim 4, wherein, The battery body includes: A single crystal substrate, on one side of the back surface of the single crystal substrate, there is provided the conductive region; And, a doped semiconductor layer, located in the conductive region; The solar cell further includes: an electrode, located on the doped semiconductor layer and in electrical contact with the doped semiconductor layer.

15. A photovoltaic module, including: A plurality of solar cells according to any one of claims 1 to 14, electrically connected to form a solar cell string; And A packaging layer, covering the surface of the solar cell.

Images