Solar cell, manufacturing method thereof and photovoltaic module

Abstract

The invention discloses a solar cell, a manufacturing method thereof and a photovoltaic module, relates to the technical field of photovoltaic, and aims to improve the carrier transport performance of an electrode structure and facilitate the improvement of the photoelectric conversion efficiency of the solar cell. The solar cell comprises a cell substrate and an electrode structure formed on the cell substrate. The electrode structure comprises a plurality of electrodes, and each electrode is provided with a main body part and continuous transition parts located on the two sides of the main body part in the width direction. The average height of the body portion is greater than the average height of the continuous transition portion, and the boundary of the continuous transition portion away from the body portion is substantially parallel to the boundary of the body portion. The manufacturing method of the solar cell is used for manufacturing the solar cell. The photovoltaic module comprises the solar cell.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a solar cell and a manufacturing method thereof, and a photovoltaic module. Background Art

[0002] Photovoltaic solar cells are devices that directly convert light energy into electrical energy through the photoelectric effect. How to improve the photoelectric conversion efficiency of the above solar cells has always been the top priority in solar cell design and optimization.

[0003] However, the transmission performance of the electrode structure included in the existing solar cell is poor, which is not conducive to improving the photoelectric conversion efficiency of the solar cell. Summary of the invention

[0004] The object of the present invention is to provide a solar cell and a manufacturing method thereof, and a photovoltaic module, which are used to improve the carrier transport performance of the electrode structure, thereby improving the photoelectric conversion efficiency of the solar cell.

[0005] In order to achieve the above-mentioned object, the present invention provides a solar cell, which comprises: a cell substrate, and an electrode structure formed on the cell substrate. The electrode structure comprises a plurality of electrodes, each electrode having a main body and continuous transition portions located on both sides of the main body along the width direction. The average height of the main body is greater than the average height of the continuous transition portions, and the boundary of the continuous transition portion away from the main body is substantially parallel to the boundary of the main body.

[0006] In the case of adopting the above technical solution, compared with the existing electrode structure manufactured by screen printing process, which has a plurality of discretely distributed conductive residues formed by part of the conductive paste entering the gap between the screen printing screen and the battery substrate due to the poor sealing between the screen printing screen and the battery substrate, the two sides of each electrode in the present invention along the width direction are continuous transition parts, and the continuous transition part is a transition part without interruption, and the continuous transition part is continuous and uninterrupted along the width direction and the length direction of the electrode. Based on this, the carriers generated after the battery substrate absorbs photons collected in the continuous transition part can be conducted to the main body connected to itself, and the collected carriers will not be unable to be extracted due to its own discreteness, thereby improving the carrier collection capacity of the electrode structure.

[0007] Secondly, when the boundary of the continuous transition portion away from the main body is roughly parallel to the boundary of the main body, the widths of the various parts of the continuous transition portion along the length direction are roughly the same, so that the continuous transition portion can improve the adhesion of the various parts of the electrode along the length direction on the surface of the electrode base to be roughly the same, thereby ensuring the structural stability of the various parts of the electrode along the length direction; at the same time, the continuous transition portion can also improve the conductivity of the various parts of the electrode to be roughly the same, so that the various parts of the electrode have roughly the same carrier collection ability, which is beneficial for each part of the battery base of the solar cell to have a balanced number of carriers in the working state, reducing the probability of recombination due to uneven carrier distribution, and thus helping to improve the photoelectric conversion efficiency of the solar cell.

[0008] As a possible implementation solution, the width of the continuous transition portion is greater than or equal to 0.5 μm and less than or equal to 15 μm.

[0009] When the above technical solution is adopted, the width of the continuous transition portion is within the above range, which can prevent the steepness of the transition between the two sides of the electrode along the width direction relative to the top of the electrode due to the small width of the continuous transition portion, thereby ensuring that the electrode has a high mechanical strength. In addition, it can also prevent the shading area of ​​the continuous transition portion from being large due to the large width of the above continuous transition portion, thereby reducing the total shading area of ​​the electrode structure, which is conducive to allowing more light to be refracted into the battery substrate through the side of the battery substrate where the electrode structure is formed, further improving the photoelectric conversion efficiency of the solar cell.

[0010] As a possible implementation scheme, the angle between the surface of the continuous transition portion away from the main body and the horizontal plane is greater than or equal to 10° and less than 90°. In this case, the angle between the surface of the continuous transition portion away from the main body and the horizontal plane is within the above range, which can prevent the steepness of the transition of the two sides of the electrode along the width direction relative to the side of the electrode structure away from the battery substrate due to the large angle, thereby ensuring that the electrode has a high mechanical strength. In addition, when the maximum height of the continuous transition portion is constant, it can also prevent the continuous transition portion from extending too wide along the width direction of the main body due to the small angle, thereby reducing the shading area of ​​the continuous transition portion on the side of the battery substrate where the electrode structure is formed, which is conducive to allowing more light to be refracted into the battery substrate through the side of the battery substrate where the electrode structure is formed, further improving the photoelectric conversion efficiency of the solar cell.

[0011] As a possible implementation scheme, the height of each position of the continuous transition portion gradually decreases along the width direction of the main body and away from the main body. In this case, the continuous transition portion has a higher structural stability, further improving the adhesion of each electrode on the surface of the battery substrate and improving the structural reliability of the solar cell.

[0012] As a possible implementation scheme, the surface on which the electrode structure is formed on the battery substrate is the first surface, and the surface on the side of the electrode structure facing away from the battery substrate is the second surface. The first surface and the second surface are both velvet surfaces. The height of each position of the second surface increases as the height of the corresponding position of the first surface increases, and the height of each position of the second surface decreases as the height of the corresponding position of the first surface decreases.

[0013] In the case of adopting the above technical solution, in the actual application process, it is necessary to connect multiple solar cells in series through interconnectors such as welding strips to form a solar cell string so that the output voltage of the photovoltaic module meets the actual working requirements. And it can be understood that the interconnector is usually in contact with the surface of the side of the electrode structure away from the battery substrate. In this case, the electrode structure formed on the first surface above, the surface of the side away from the battery substrate (i.e., the second surface) is also velvet. At this time, from a microscopic point of view, the velvet is a surface with an uneven micro-velvet structure, so compared with the second surface of the electrode structure being a plane, the surface roughness of the second surface of the electrode structure in the present invention is greater, so that its surface area is larger, thereby increasing the contact area between the electrode structure and the interconnector, increasing the connection adhesion between the interconnector and the electrode structure, and improving the connection strength of the two, and finally improving the structural stability of the photovoltaic module including the solar cell. From a macroscopic point of view, the velvet is an overall flat and long-range consistent surface, that is, the second surface is a macroscopic flat surface, which is conducive to making the connection tension between the various parts of the electrode structure and the interconnector uniform. At the same time, when the contact surface between the interconnect and the electrode structure is a relatively flat surface, it is also beneficial for at least most areas of the interconnect to be in contact with the electrode structure, so that there is good contact between the two. Secondly, the height of each position of the second surface increases with the increase of the height of the corresponding position of the first surface, and the height of each position of the second surface decreases with the decrease of the height of the corresponding position of the first surface. Based on this, in the actual manufacturing process, while manufacturing the first surface with a light trapping effect, an electrode structure with corresponding undulating characteristics can be manufactured based on the first surface of the velvet surface. In order to obtain an electrode structure with a velvet surface on the second surface, there is no need to perform additional velveting treatment on the conductive material after depositing the electrode structure, thereby reducing the manufacturing difficulty of the electrode structure with a velvet surface on the second surface and simplifying the manufacturing process of the electrode structure.

[0014] As a possible implementation scheme, when both the first surface and the second surface are velvet, and the thickness of the electrode structure is greater than or equal to 0.5 μm and less than or equal to 15 μm, the height variation amplitude of each position of the second surface and the corresponding position of the first surface are substantially the same.

[0015] When the above technical solution is adopted, the second surface of the electrode structure and the first surface of the battery substrate have substantially the same surface undulation characteristics, so that the second surface of the electrode structure can have a larger specific surface area, so that the connection adhesion between the interconnector and the electrode structure is increased, and the second surface of the electrode structure is ensured to be a macroscopically flat surface, which is conducive to making the connection tension between each part of the electrode structure and the interconnector uniform. In other words, while the electrode structure and the interconnector have a larger connection adhesion, the two also have a higher connection tension uniformity.

[0016] As a possible implementation scheme, when both the first surface and the second surface are velvet, and the thickness of the electrode structure is greater than or equal to 0.5 μm and less than or equal to 15 μm, the thickness of the electrode structure at various positions is the same. The beneficial effects in this case can be referred to the beneficial effect analysis of the height variation amplitude of various positions on the second surface and the corresponding positions on the first surface being substantially the same when the thickness of the electrode structure is greater than or equal to 0.5 μm and less than or equal to 15 μm, which will not be repeated here.

[0017] As a possible implementation method, when both the first surface and the second surface are velvet, and the thickness of the electrode structure is greater than 15μm and less than or equal to 50μm, the thickness of the electrode structure at the recessed position is greater than the thickness of the electrode structure at the raised position. In this case, the thickness of the electrode structure is relatively large, and the width of the electrode structure can be appropriately reduced while ensuring that the resistivity of the electrode structure remains unchanged, thereby ensuring that the electrode structure has good conductivity and current collection capabilities, while being conducive to reducing the shading area of ​​the electrode structure when the resistance of the electrode structure is constant, thereby improving the photoelectric conversion efficiency of the solar cell.

[0018] As a possible implementation scheme, when both the first surface and the second surface are velvet, the roughness within every 10 microns on the second surface is greater than or equal to 170nm and less than or equal to 900nm; the roughness within every 100 microns on the second surface is greater than or equal to 200nm and less than or equal to 900nm.

[0019] In the case of adopting the above technical solution, when other factors are the same, the roughness of the surface is proportional to the surface area of ​​the surface. Based on this, from a microscopic perspective, the roughness within every 10 microns and every 100 microns of the second surface of the electrode structure is within the above range, which can prevent the surface area of ​​the second surface from being small due to the above roughness, ensure that there is a high connection adhesion between the electrode structure and the interconnection part, and further reduce the risk of the interconnection part being detached from the electrode structure when the interconnection is connected to the circuit. At the same time, it can also prevent the part of the interconnection part with a relatively flat contact surface from being difficult to fully contact with the corresponding area of ​​the second surface of the electrode structure due to the high degree of unevenness of the second surface due to the above roughness, increase the actual contact area between the two, and ensure that there is good interface electrical contact between the two.

[0020] As a possible implementation scheme, when both the first surface and the second surface are suede surfaces, the absolute value of the difference between the roughness of the first surface and the roughness of the second surface is greater than or equal to 0.5 μm and less than 5 μm.

[0021] When the above technical solution is adopted, the absolute value of the difference between the roughness of the first surface and the roughness of the second surface is small, that is, the difference in the surface morphology of the two is small. In other words, the second surface of the electrode structure has an undulating feature that is basically consistent with the first surface, which is conducive to the second surface of the electrode structure also having a high macroscopic surface flatness, and can further improve the uniformity of the connection tension between the various parts of the electrode structure and the interconnection. At the same time, it is conducive to the second surface of the electrode structure also having a certain microscopic surface roughness, ensuring that the electrode structure and the interconnection have a high connection strength, reducing the risk of the interconnection being detached from the electrode structure when the interconnection is connected to the circuit, and improving the structural reliability of the photovoltaic module including the solar cell.

[0022] As a possible implementation solution, the suede surface is a pyramid-shaped suede surface.

[0023] When the above technical solution is adopted, since the pyramid-shaped velvet surface has a pentahedral velvet structure, compared with a velvet structure with a small number of surfaces such as V-shaped grooves, the pyramid-shaped velvet structure is conducive to increasing the specific surface area of ​​the velvet surface, thereby reducing the reflectivity of the first surface; at the same time, it can also increase the contact area between the electrode structure and the first surface, and reduce the contact resistance. In addition, when the second surface is a pyramid-shaped velvet surface, the connection tension between the electrode structure and the interconnection member can be increased, and the connection strength between the electrode structure and the interconnection member can be further improved.

[0024] As a possible implementation scheme, the surface on which the electrode structure is formed on the battery substrate is the first surface, and the surface on the side of the electrode structure facing away from the battery substrate is the second surface. Both the first surface and the second surface are planes, and the roughness of the second surface within every 10 microns is greater than 10nm and less than 40nm.

[0025] In the case of adopting the above technical solution, the second surface of the electrode structure in contact with the interconnection is a plane with a relatively flat surface. Because within a certain range, the roughness of the surface is positively correlated with the degree of unevenness of the surface, the second surface of the electrode structure in the present invention has a lower degree of surface unevenness than the electrode structure with a larger outer surface roughness, so that there are more contact points between the second surface of the electrode structure and the contact surface of the interconnection, which can increase the relative contact area between the two, and then reduce the contact resistance between the two, which is beneficial to the transmission of carriers and improves the electrical performance of the photovoltaic module including the solar cell. In addition, when the surfaces of each region of the second surface of the electrode structure are all regional surfaces with low roughness and flatness, even if the actual placement position of the interconnection on the electrode structure deviates from the expected placement position during the actual manufacturing process, it can also ensure that the interconnection has a larger relative contact area with the electrode structure, which can improve the interconnection consistency between the interconnection and the electrode structure, and can also reduce the position accuracy requirements for placing the interconnection on the electrode structure, thereby reducing the manufacturing difficulty of the photovoltaic module including the solar cell. Secondly, when the surfaces of each region on the second surface of the electrode structure are all low-roughness and flat regional surfaces, it is also beneficial to improve the uniformity of the connection tension between the regions where the interconnection parts contact the electrode structure, and to improve the structural stability and electrical performance of the photovoltaic module. Furthermore, when the width and height of the electrode structure are fixed values, compared with the electrode structure with an uneven outer surface, when the second surface of the electrode structure is a plane with low roughness and a flat surface, the stacking volume of the electrode structure is larger, which is beneficial to reduce the on-resistance of the electrode structure and improve the conductivity of the electrode structure. In addition, when the first surface is a plane, an electrode structure with corresponding surface features can be manufactured based on the flat first surface. In order to obtain an electrode structure with a flat outer surface, it is not necessary to perform additional flattening treatment on the conductive material of the electrode structure after depositing it, thereby reducing the manufacturing difficulty of the electrode structure with a flat second surface and simplifying the manufacturing process of the electrode structure.

[0026] As a possible implementation solution, when the first surface is a plane, the roughness of the first surface is greater than or equal to 0 and less than or equal to 500 nm.

[0027] When the above technical solution is adopted, when the electrode structure is manufactured on the first surface of the battery substrate, the surface undulation of the second surface of the electrode structure is often affected by the surface undulation of the first surface of the battery substrate. Based on this, when the first surface is a plane and the roughness of the first surface is within the above range, the first surface is a relatively flat surface, which is conducive to forming an electrode structure with a lower roughness of the second surface on the relatively flat first surface, ensuring that each area of ​​the second surface of the electrode structure has a high flatness, further increasing the relative contact area between the electrode structure and the interconnection, and improving the uniformity of the connection tension between the electrode structure and the interconnection.

[0028] As a possible implementation scheme, when the second surface is a plane, the roughness of the second surface within every 100 microns is greater than or equal to 40nm and less than 300nm. The beneficial effects in this case can refer to the beneficial effect analysis of the roughness of the second surface within every 10 microns greater than 10nm and less than 40nm described above, which will not be repeated here.

[0029] As a possible implementation scheme, when the first surface and the second surface are planes, the difference between the roughness of the first surface and the roughness of the second surface is greater than or equal to 20 nm and less than 300 nm.

[0030] In the case of adopting the above technical solution, when the first surface and the second surface are planes, and the difference between the roughness of the first surface and the roughness of the second surface is within the above range, the difference between the roughness of the first surface and the roughness of the second surface is small, that is, the difference in surface morphology between the two is small. In other words, the second surface of the electrode structure has a surface feature that is substantially consistent with the first surface, which is conducive to forming an electrode structure with a second surface having a higher macroscopic surface flatness on a relatively flat first surface, and can further improve the uniformity of the connection tension between each part of the electrode structure and the interconnection member.

[0031] As a possible implementation scheme, when the first surface and the second surface are planes, the surface height difference of the second surface is greater than or equal to 10 nm and less than or equal to 300 nm.

[0032] When the above technical solution is adopted, in the actual application process, within a certain range, the surface height difference of the second surface is proportional to the roughness of the second surface. Among them, the smaller the surface height difference of the second surface, the more conducive to reducing the roughness of the second surface, and the larger the surface height difference of the second surface leads to an increase in the roughness of the second surface. Based on this, when the second surface is a plane and the surface height difference of the second surface of the electrode structure is within the above range, it can prevent the second surface from having poor flatness due to the large height difference of the second surface, and ensure that the contact resistance and connection tension uniformity between the electrode structure and the interconnection meet the working requirements.

[0033] As a possible implementation scheme, the surface of the electrode structure on one side facing away from the battery substrate is composed of granular conductive protrusions, and there is no gap between adjacent conductive protrusions.

[0034] When the above technical solution is adopted, the granular conductive protrusions are conductive structures that protrude outward relative to the main surface of the electrode structure on the side facing away from the battery substrate. Therefore, when the surface of the electrode structure on the side facing away from the battery substrate is composed of granular conductive protrusions and there is no gap between adjacent conductive protrusions, the side of the electrode structure facing away from the battery substrate can have a larger surface area, further increasing the connection adhesion between the electrode structure and the interconnection part, and reducing the risk of the interconnection part being detached from the electrode structure when the interconnection is connected to the circuit.

[0035] As a possible implementation solution, the size of the conductive protrusion is greater than or equal to 100 nm and less than or equal to 2000 nm.

[0036] In the case of adopting the above technical solution, the size of the conductive protrusion is within the above range, which can prevent the surface area of ​​the side of the electrode structure away from the battery substrate from increasing significantly due to the small size of the conductive protrusion, ensure that the electrode structure and the interconnection have a high connection adhesion, and further improve the connection strength between the electrode structure and the interconnection. At the same time, it can also prevent the conductive protrusion from being too large, so that the macroscopic surface flatness of the second surface is affected by the conductive protrusion and reduced, ensure that the parts of the electrode structure and the interconnection have a high connection tension uniformity, and ensure that the interconnection and the electrode structure have good contact.

[0037] As a possible implementation scheme, the electrode structure includes a collector electrode and a bus electrode that are integrally formed and cross-arranged.

[0038] In the case of adopting the above technical solution, the collector electrode is used to collect the carriers generated by the battery substrate after absorbing photons, and conduct them to the bus electrode, and then lead out by the bus electrode. In addition, because the temperature when manufacturing the electrode structure is high, and the manufacturing environment of the electrode structure in the prior art is mostly non-vacuum state, an insulating layer of materials including metal oxides and the like is often formed on the surface of the formed electrode structure. Based on this, in the prior art, when the collector electrode and the bus electrode are manufactured step by step, there will be a certain interface resistance between the collector electrode and the bus electrode due to the existence of the insulating layer, which affects the conduction of carriers. In the present invention, the cross-arranged collector electrode and the bus electrode included in the electrode structure are integrally formed. At this time, the collector electrode and the bus electrode are formed at the same time in the actual manufacturing process, which simplifies the manufacturing process of the electrode structure, so that there will be no insulating layer byproducts generated by step-by-step manufacturing between the collector electrode and the bus electrode, and the interface resistance between the collector electrode and the bus electrode is eliminated, which is beneficial to the conduction of carriers between the two, and then it is beneficial to improve the electrical performance of solar cells.

[0039] As a possible implementation scheme, the electrode structure is a solid structure without pores. In this case, each part of the electrode structure can effectively conduct carriers, which is conducive to improving the conductivity of each part of the electrode structure. At the same time, the mechanical strength of the electrode structure can also be improved, reducing the risk of problems such as breakage or bending during the interconnection process between the electrode structure and the interconnection part or during actual use.

[0040] In a second aspect, the present invention further provides a photovoltaic module, which includes the solar cell provided by the first aspect and various implementations thereof.

[0041] The beneficial effects of the second aspect of the present invention can be analyzed by referring to the beneficial effects of the first aspect and its various implementations, and will not be repeated here.

[0042] In a third aspect, the present invention also provides a method for manufacturing a solar cell, the method comprising: first, forming a polymer mask provided with an electrode pattern. Next, transferring and fixing the polymer mask on a battery substrate. Next, under the protection of the polymer mask, forming an electrode structure on the battery substrate by vacuum coating. The electrode structure comprises a plurality of electrodes, each electrode having a main body and continuous transition portions located on both sides of the main body along the width direction. The average height of the main body is greater than the average height of the continuous transition portion, and the boundary of the continuous transition portion away from the main body is roughly parallel to the boundary of the main body.

[0043] The beneficial effects of the third aspect of the present invention can be analyzed by referring to the beneficial effects of the first aspect and its various implementations, and will not be repeated here.

[0044] As a possible implementation scheme, the deposition rate of the electrode structure formed on the battery substrate by the vacuum coating method is greater than 0 and less than or equal to 1 nm / s.

[0045] When the above technical solution is adopted, in the actual manufacturing process, within a certain range, the deposition rate is proportional to the deposition defects. Therefore, when the deposition rate of the electrode structure on the battery substrate is within the above range, the deposition rate of the electrode structure on the battery substrate is relatively small, which is beneficial to reducing the defects in the manufactured electrode structure, and further beneficial to forming a continuous transition portion continuously distributed along the length direction of the electrode on both sides of the width direction of the main body of each electrode, while ensuring that the boundary of the continuous transition portion away from the main body is roughly parallel to the boundary of the main body, thereby improving the yield of the electrode structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0047] Figure 1 It is a top view enlarged schematic diagram of an electrode structure in the related art;

[0048] Figure 2 It is an enlarged schematic top view of a first structure of an electrode structure in an embodiment of the present invention;

[0049] Figure 3 It is an enlarged schematic longitudinal cross-sectional view of the structure at the junction of the collector electrode and the bus electrode in an embodiment of the present invention;

[0050] Figure 4 It is an enlarged schematic longitudinal cross-sectional view of the structure at the junction of the collector electrode and the bus electrode in the related art;

[0051] Figure 5 It is an enlarged longitudinal cross-sectional schematic diagram of the second structure of the electrode structure in the embodiment of the present invention;

[0052] Figure 6 It is an enlarged longitudinal cross-sectional schematic diagram of a third structure of the electrode structure in an embodiment of the present invention;

[0053] Figure 7 It is an enlarged longitudinal cross-sectional schematic diagram of a fourth structure of the electrode structure in an embodiment of the present invention;

[0054] Figure 8 A longitudinal cross-sectional schematic diagram of a partial structure of a solar cell in an embodiment of the present invention;

[0055] Fig. 9 An enlarged schematic diagram of the structure of the second surface of the electrode structure with a thickness of 2 μm when the velvet surface is a pyramid-shaped velvet surface in an embodiment of the present invention;

[0056] Fig.10 It is a schematic diagram of the structure enlargement of the second surface of the electrode structure with a thickness of 5 μm when the velvet surface is a pyramid-shaped velvet surface in an embodiment of the present invention;

[0057] Fig.11 This is an enlarged schematic diagram of the structure of the second surface of the electrode structure with a thickness of 10 μm when the velvet surface is a pyramid-shaped velvet surface in an embodiment of the present invention.

[0058] Fig.12 is a schematic diagram of the second surface of the electrode structure magnified 1000 times when the first surface and the second surface are planes and the thickness of the electrode structure is 2 μm in an embodiment of the present invention;

[0059] Fig.13 is a schematic diagram of the second surface of the electrode structure magnified 1000 times when the first surface and the second surface are planes and the thickness of the electrode structure is 5 μm in an embodiment of the present invention;

[0060] Fig.14 is a schematic diagram of the second surface of the electrode structure magnified 1000 times when the first surface and the second surface are planes and the thickness of the electrode structure is 10 μm in an embodiment of the present invention;

[0061] Fig.15 is a schematic diagram of the second surface of the electrode structure magnified 5000 times when the first surface and the second surface are planes and the thickness of the electrode structure is 2 μm in an embodiment of the present invention;

[0062] Fig.16 is a schematic diagram of the second surface of the electrode structure magnified 5000 times when the first surface and the second surface are planes and the thickness of the electrode structure is 5 μm in an embodiment of the present invention;

[0063] Fig.17 is a schematic diagram of the second surface of the electrode structure magnified 5000 times when the first surface and the second surface are planes and the thickness of the electrode structure is 10 μm in an embodiment of the present invention;

[0064] Fig.18 It is an enlarged schematic diagram of a top view of an electrode structure when the first surface and the second surface are planes in an embodiment of the present invention;

[0065] Fig.19 It is an enlarged longitudinal cross-sectional schematic diagram of a fifth structure of the electrode structure in an embodiment of the present invention;

[0066] Fig. 20 This is an enlarged longitudinal cross-sectional view of the sixth structure of the electrode structure in the embodiment of the present invention.

[0067] Fig.21 It is an enlarged schematic diagram of the longitudinal section of the electrode structure in the related art.

[0068] Figure numerals: 11 is a battery substrate, 12 is a first surface, 13 is an electrode structure, 14 is a second surface, 15 is a conductive protrusion, 16 is a collecting electrode, 17 is a bus electrode, 18 is a main body, 19 is a continuous transition portion, and 20 is a pore. DETAILED DESCRIPTION

[0069] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0070] Various structural schematic diagrams according to embodiments of the present disclosure are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may further design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0071] In the context of the present disclosure, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. In addition, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "under" the other layer / element. In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0072] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0073] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] Photovoltaic solar cells are devices that directly convert light energy into electrical energy through the photoelectric effect. How to improve the photoelectric conversion efficiency of the above solar cells has always been a top priority in solar cell design and optimization. For example: In the actual process of manufacturing solar cells, the semiconductor substrate of the solar cell to be manufactured is generally first subjected to a velvet treatment to form a velvet structure at least on the light-facing surface of the semiconductor substrate. The velvet structure on the light-facing surface can trap light to reduce the reflection of light by the solar cell, so that more light can be refracted into the solar cell, thereby improving the utilization rate of light energy by the solar cell.

[0075] However, the transmission performance of the electrode structure included in the existing solar cells is poor, which is not conducive to improving the photoelectric conversion efficiency of the solar cells. Specifically, the electrode structure of the existing solar cells is usually formed by screen printing. Among them, because the main material used in the screen printing process is silver, compared with base metals such as copper or aluminum, the price of silver is relatively high, which is not conducive to reducing the manufacturing cost of the electrode structure. In addition, Figure 1 As shown, the electrode structure manufactured by screen printing process has many discretely distributed conductive residues on both sides of each electrode along the width direction. These conductive residues are not in contact with the electrode, so they not only have no carrier extraction function, but also cannot provide physical support for the electrode. Secondly, the conductive residues are made of metal materials, and metal has reflective properties, so these conductive residues are not transparent, resulting in a reduction in the light-transmitting area on the side of the solar cell with the electrode structure, which in turn leads to a low utilization rate of light by the solar cell.

[0076] In order to solve the above technical problems, in the first aspect, an embodiment of the present invention provides a solar cell. In terms of the type of battery, the solar cell provided by the embodiment of the present invention can be any type of solar cell such as a PERC (Passivated Emitter and Rear Cell) battery, an HJT (Heterojunction Technology) battery, an SE (selective emitter) battery, a TOPcon (Tunnel Oxide Passivated Contact) battery, etc. In terms of the formation position of the positive and negative electrodes of the battery, the solar cell provided by the embodiment of the present invention can be a double-sided contact solar cell in which the positive and negative electrodes are located on different surfaces, or it can be a back contact battery in which the positive and negative electrodes are both located on the backlight side.

[0077] Specifically, the solar cell comprises: a cell substrate and an electrode structure formed on the cell substrate. Figure 2 As shown, the electrode structure includes a plurality of electrodes, each electrode having a main body 18 and continuous transition portions 19 located on both sides of the main body 18 along the width direction. The average height of the main body 18 is greater than the average height of the continuous transition portion 19, and the boundary of the continuous transition portion 19 away from the main body 18 is substantially parallel to the boundary of the main body 18.

[0078] Specifically, when the angle between the boundary of the continuous transition portion away from the main body and the boundary of the main body is greater than or equal to 0 and less than or equal to A° (A° may be 5°, for example), it can be considered that the boundary of the continuous transition portion away from the main body is substantially parallel to the boundary of the main body. For example: when the angle between the boundary of the continuous transition portion away from the main body and the boundary of the main body is 0°, 1°, 2°, 3°, 4° or 5°, it can be considered that the boundary of the continuous transition portion away from the main body is substantially parallel to the boundary of the main body.

[0079] When the above technical solution is adopted, Figure 1 and Figure 2As shown, compared with the existing electrode structure manufactured by screen printing process, which has a plurality of discretely distributed conductive residues formed by part of the conductive paste entering the gap between the screen printing screen and the battery substrate 11 due to the poor sealing between the screen printing screen and the battery substrate 11, each electrode in the embodiment of the present invention has continuous transition parts 19 on both sides along the width direction, and the continuous transition part 19 is a transition part without interruption, and the continuous transition part 19 is continuous and uninterrupted along the width direction and the length direction of the electrode. Based on this, the continuous transition part 19 collects the carriers generated after the battery substrate 11 absorbs photons, and can conduct them to the main body 18 connected to itself, without the collected carriers being unable to be extracted due to its own discreteness, thereby improving the carrier collection capacity of the electrode structure. Secondly, when the boundary of the continuous transition portion 19 away from the main body 18 is roughly parallel to the boundary of the main body 18, the widths of the various parts of the continuous transition portion 19 along the length direction are roughly the same, so that the continuous transition portion 19 can improve the adhesion of the various parts of the electrode along the length direction on the surface of the electrode base to be roughly the same, thereby ensuring the structural stability of the various parts of the electrode along the length direction; at the same time, the continuous transition portion 19 can also improve the conductivity of the various parts of the electrode to be roughly the same, so that the various parts of the electrode have roughly the same carrier collection ability, which is beneficial for the solar cell to have a balanced number of carriers in each part of the battery base 11 when the solar cell is in the working state, reducing the probability of recombination due to uneven carrier distribution, and thus helping to improve the photoelectric conversion efficiency of the solar cell.

[0080] In actual application, the specific structure of the above-mentioned battery substrate can be determined according to the type of solar cell, and is not specifically limited here. For example, in the case where the solar cell is a heterojunction cell, the battery substrate can at least include a silicon substrate, and an intrinsic amorphous silicon layer and an impurity-doped amorphous silicon layer stacked in sequence on one side of the silicon substrate along the thickness direction of the silicon substrate. The conductivity type of the impurities in the impurity-doped amorphous silicon layer is opposite to the conductivity type of the silicon substrate.

[0081] In addition, the surface morphologies of the light-facing side and the backlight side of the battery substrate can be determined according to the actual application scenario and are not specifically limited here.

[0082] Specifically, the light-facing surface of the battery substrate can be a plane or a velvet surface. Among them, when the light-facing surface of the battery substrate is a plane, the light-facing surface of the battery substrate is relatively flat, which is beneficial to improving the quality of the film layer formed on the light-facing side of the battery substrate. For example: when the solar cell also includes a surface passivation layer formed on the light-facing side of the battery substrate, and the light-facing surface is a plane, the flat surface of the light-facing surface is beneficial to improving the passivation effect of the surface passivation layer and reducing the carrier recombination efficiency on the light-facing side of the battery substrate. When the light-facing surface of the battery substrate is a velvet surface, the light-facing surface of the battery substrate has a light-trapping effect, which can refract more light into the battery substrate, which is beneficial to improving the utilization rate of light by the solar cell.

[0083] As for the backlight surface of the battery substrate, it can be a plane or a velvet surface. The beneficial effects of the plane or velvet surface of the backlight surface of the battery substrate are similar to the beneficial effects of the plane or velvet surface of the light-facing surface described above, and will not be repeated here.

[0084] Among them, the roughness when the light-facing surface and / or the backlight surface of the battery substrate is a plane, and the type, size and roughness of the velvet structure when the light-facing surface and / or the backlight surface of the battery substrate is a velvet surface can be determined according to the actual application scenario, as long as they can be applied to the solar cell provided in the embodiment of the present invention.

[0085] Regarding the above-mentioned electrode structure, in terms of the formation position, the above-mentioned electrode structure can be formed only on the light-facing side of the battery substrate; it can also be formed only on the backlight side of the battery substrate; or the above-mentioned electrode structure can be formed on both the light-facing side and the backlight side of the battery substrate.

[0086] From a structural perspective, the embodiments of the present invention do not specifically limit the specific structure of the electrode structure, the number and distribution of electrodes included in the electrode structure, and can be determined based on actual application scenarios.

[0087] The electrode structure may only include a plurality of collector electrodes extending along the first direction and spaced apart along the second direction. In the above case, each electrode included in the electrode structure is a collector electrode. In addition, the first direction and the second direction may be any two different directions parallel to the surface of the battery substrate. The collector electrode may be in a straight line, a wavy line, an arc-shaped curve, or the like.

[0088] Alternatively, the electrode structure may also include a plurality of collector electrodes and at least one bus electrode. In this case, the plurality of electrodes included in the electrode structure are a plurality of collector electrodes and at least one bus electrode, and each electrode is a collector electrode or a bus electrode. Specifically, the plurality of collector electrodes extend along the first direction and are spaced apart along the second direction. The morphology of each collector electrode can refer to the foregoing. The bus electrode extends along the second direction, and each bus electrode is coupled with the collector electrode included in the electrode structure. Furthermore, when the electrode structure includes a plurality of bus electrodes, the plurality of bus electrodes are spaced apart along the first direction. The bus electrode may be in a straight line, a wavy line, an arc-shaped curve, or other shapes.

[0089] Specifically, when the electrode structure includes the above-mentioned cross-arranged collector electrode and bus electrode, the collector electrode and the bus electrode may be formed in a non-integrated manner, that is, the collector electrode and the bus electrode are formed in steps. Figure 3As shown, the collector electrode 16 and the bus electrode 17 can be integrally formed. The integrally formed collector electrode 16 and the bus electrode 17 means that the collector electrode 16 and the bus electrode 17 are manufactured and formed at the same time, that is, the collector electrode 16 and the bus electrode 17 can be formed at the same time through a single manufacturing process. In this case, the collector electrode 16 is used to collect the carriers generated by the battery substrate 11 after absorbing photons, and conduct them to the bus electrode 17, and then the bus electrode 17 is led out. In addition, as Figure 4 As shown, because the temperature during the manufacture of the electrode structure is high, and the manufacturing environment of the electrode structure in the prior art is mostly non-vacuum, an insulating layer of materials including metal oxides is often formed on the surface of the formed electrode structure. Based on this, in the prior art, when the collector electrode 16 and the bus electrode 17 are manufactured step by step, there will be a certain interface resistance between the collector electrode 16 and the bus electrode 17 due to the existence of the insulating layer, which affects the conduction of carriers. Figure 3 As shown, the electrode structure in the embodiment of the present invention includes a cross-arranged collecting electrode 16 and a bus electrode 17 which are integrally formed. In this case, the collecting electrode 16 and the bus electrode 17 are formed simultaneously during the actual manufacturing process, so that there will be no insulating layer by-products generated by step-by-step manufacturing between the collecting electrode 16 and the bus electrode 17, thereby eliminating the interface resistance between the collecting electrode 16 and the bus electrode 17, which is beneficial to the carrier conduction between the two, and further beneficial to improving the electrical performance of the solar cell.

[0090] In terms of size, the solar cell provided by the embodiment of the present invention does not specifically limit the size of the main body and the continuous transition part included in each electrode, as long as the boundary of the continuous transition part away from the main body is roughly parallel to the boundary of the main body.

[0091] Exemplarily, the width of the above-mentioned continuous transition portion is greater than or equal to 0.5μm and less than or equal to 15μm. For example, the width of the continuous transition portion may be 0.5μm, 3μm, 6μm, 9μm, 12μm or 15μm, etc. In this case, the width of the continuous transition portion is within the above-mentioned range, which can prevent the steepness of the transition of the two sides of the electrode along the width direction relative to the top of the electrode due to the small width of the continuous transition portion, thereby ensuring that the electrode has a high mechanical strength. In addition, it can also prevent the shading area of ​​the continuous transition portion from being large due to the large width of the above-mentioned continuous transition portion, thereby reducing the total shading area of ​​the electrode structure, which is conducive to allowing more light to be refracted into the battery substrate through the side of the battery substrate where the electrode structure is formed, thereby further improving the photoelectric conversion efficiency of the solar cell.

[0092] Among them, in the actual manufacturing process of the solar cell provided by the embodiment of the present invention, it is necessary to form an electrode structure under the masking action of the corresponding mask layer. In addition, the electrode structure will have temperature changes during the manufacturing process, and mask layers with different characteristics will be used to adapt to the different surface morphologies of different battery substrates. The connection strength between the mask layer with different characteristics and the first surface of the battery substrate, the thin film properties of different mask layers, etc. will affect the width of the continuous transition portion. Based on this, the width of the continuous transition portion can also be determined according to the surface morphology of the battery substrate on which the electrode structure is formed. For example: when the surface of the battery substrate formed with the battery substrate is a plane, the width of the continuous transition portion can be greater than or equal to 0.5μm and less than or equal to 7μm. For another example: when the surface of the battery substrate formed with the battery substrate is a velvet surface, the width of the continuous transition portion can be greater than or equal to 1μm and less than or equal to 15μm.

[0093] In addition, the surface of the continuous transition portion facing away from the main body portion may be arranged vertically relative to the horizontal plane. Figures 5 to 7 As shown, the surface of the continuous transition portion 19 away from the main body 18 can also be inclined relative to the horizontal plane. In this case, the height of the electrode on both sides along the width direction gradually decreases, so that the transition of the electrode with a certain height on both sides along the width direction relative to the first surface 12 is smoother, which can improve the mechanical strength of the electrode structure and reduce the risk of damage to the electrode structure. In addition, the surface of the continuous transition portion 19 away from the main body 18 is inclined relative to the horizontal plane, which can make the surface of the continuous transition portion 19 away from the main body 18 have a certain reflection effect on the light on the side of the first surface 12, and part of the light reflected by it is refracted into the second surface 14, which is beneficial to improve the utilization rate of light by solar cells.

[0094] Wherein, along the width direction of the main body and in the direction away from the main body, the height of each position of the continuous transition portion gradually decreases, and the rate of change of the height gradually decreases is substantially the same. Figure 6 As shown, along the width direction of the main body and away from the main body, the height change rate of some areas of the continuous transition part is approximately the same, while the height of the remaining areas drops significantly. For example, the height change rate of the area adjacent to the main body of the continuous transition part is approximately the same, while the height of the part away from the main body by a distance greater than a preset distance drops significantly.

[0095] Specifically, when the surface of the continuous transition portion away from the main body is inclined relative to the horizontal plane, the angle between the surface of the continuous transition portion away from the main body and the horizontal plane can be determined according to the actual manufacturing process and actual application scenario, and is not specifically limited here.

[0096] Exemplarily, the angle between the surface of the continuous transition portion away from the main body and the horizontal plane is greater than or equal to 10° and less than 90°. For example, the angle between the surface of the continuous transition portion away from the main body and the horizontal plane can be 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80° or 89°, etc. In this case, the angle between the surface of the continuous transition portion away from the main body and the horizontal plane is within the above range, which can prevent the steepness of the transition of the two sides of the electrode along the width direction relative to the side of the electrode structure away from the battery substrate due to the large angle, and ensure that the electrode structure has a high mechanical strength. In addition, when the maximum height of the continuous transition portion is constant, it can also prevent the continuous transition portion from extending too wide along the width direction of the main body due to the small angle, and reduce the shading area of ​​the continuous transition portion on the side of the battery substrate where the electrode structure is formed, which is conducive to allowing more light to be refracted into the battery substrate through the side of the battery substrate where the electrode structure is formed, and further improve the photoelectric conversion efficiency of the solar cell.

[0097] Among them, as mentioned above, in the actual manufacturing process of the solar cell provided by the embodiment of the present invention, it is necessary to form an electrode structure under the masking action of the corresponding mask layer. In addition, the electrode structure will have temperature changes during the manufacturing process, and mask layers with different characteristics will be used to adapt to the different surface morphologies of different battery substrates. The connection strength between the mask layer with different characteristics and the first surface of the battery substrate and the thin film characteristics of different mask layers will affect the angle between the surface of the continuous transition portion away from the main body and the horizontal plane. Based on this, the angle between the surface of the continuous transition portion away from the main body and the horizontal plane can also be determined according to the surface morphology of the battery substrate on which the electrode structure is formed. For example: when the surface of the battery substrate on which the electrode structure is formed is velvet, the above angle can be greater than or equal to 45° and 90°. For another example: when the surface of the battery substrate on which the electrode structure is formed is a plane, the above angle can be greater than or equal to 10° and less than or equal to 60°. In this case, compared with the angle between the surface of the continuous transition portion away from the main body and the horizontal plane when the surface of the battery substrate is velvet, when the surface of the battery substrate is flat, the angle between the surface of the continuous transition portion away from the main body and the horizontal plane is smaller, which is more conducive to increasing the surface adhesion between the electrode structure and the battery substrate.

[0098] As for the main body, illustratively, the thickness of the main body can be greater than or equal to 500nm and less than or equal to 30μm. For example, the thickness of the main body can be 500nm, 1μm, 10μm, 20μm or 30μm, etc. In this case, the thickness of the main body included in each electrode is within the above range, which can prevent the transmission resistance of the electrode from being high due to the small thickness of the main body included in the electrode when the width of the electrode structure is constant, thereby ensuring that the electrode structure has good conductivity. At the same time, it can also prevent the large amount of consumables used in the electrode structure and the long process cycle due to the large thickness of the main body included in the electrode, which is beneficial to control the manufacturing cost of solar cells and improve the process efficiency of solar cells.

[0099] Exemplarily, the width of the main body may be greater than or equal to 10 μm and less than or equal to 1000 μm. For example, the width of the main body may be 10 μm, 200 μm, 400 μm, 600 μm, 800 μm or 1000 μm, etc. In this case, the width of the main body included in each electrode is within the above range, which can prevent the electrode from easily collapsing during manufacturing or interconnection due to the large thickness-to-width ratio of the electrode without increasing the resistance due to the small width of the main body, thereby improving the structural stability of the electrode. At the same time, it can also prevent the electrode from having a large shading area due to a large width, thereby ensuring that the solar cell has a high photoelectric conversion efficiency.

[0100] Among them, the width of the main body can also be determined according to the surface morphology of the battery substrate on which the electrode structure is formed. For example: when the surface of the battery substrate formed with the battery substrate is velvet, the width of the main body can be greater than or equal to 10μm and less than or equal to 500μm. For another example: when the surface of the battery substrate formed with the battery substrate is flat, the width of the main body can be greater than or equal to 10μm and less than or equal to 1000μm. In the above case, when the upper limit value of the width of the main body when the surface of the battery substrate formed with the electrode structure is flat is greater than the upper limit value of the width of the main body when the surface of the battery substrate formed with the electrode structure is velvet, it can ensure that the electrode structure has a small shading area while ensuring that the electrode structure and the battery substrate have sufficient contact area to reduce the contact resistance and increase the adhesion between the electrode structure and the electrode substrate.

[0101] In terms of surface morphology, the surface morphology of the electrode structure on the side facing away from the battery substrate can be determined based on the surface morphology of the battery substrate on the side where the electrode structure is formed, and is not specifically limited here.

[0102] For example, Figure 8As shown, the surface on which the electrode structure 13 is formed on the battery substrate 11 is the first surface 12, and the surface on one side of the electrode structure 13 away from the battery substrate 11 is the second surface 14. Both the first surface 12 and the second surface 14 are velvet. The height of each position of the second surface 14 increases as the height of the corresponding position of the first surface 12 increases, and the height of each position of the second surface 14 decreases as the height of the corresponding position of the first surface 12 decreases. In this case, in the actual application process, it is necessary to connect multiple solar cells in series through interconnectors such as welding strips to form a solar cell string so that the output voltage of the photovoltaic module meets the actual working requirements. And it can be understood that the interconnector is usually in contact with the surface on one side of the electrode structure 13 away from the battery substrate 11. In this case, the electrode structure 13 formed on the first surface 12, its surface on one side away from the battery substrate 11 (i.e., the second surface 14) is also velvet. At this time, from a microscopic perspective, the velvet surface is a surface with an uneven micro-velvet structure. Therefore, compared with the second surface 14 of the electrode structure 13 being a plane, the surface roughness of the second surface 14 of the electrode structure 13 in the embodiment of the present invention is greater, so that its surface area is larger, so that the contact area between the electrode structure 13 and the interconnection member can be increased, the connection adhesion between the interconnection member and the electrode structure 13 can be increased, and the connection strength between the two can be improved, and finally the structural stability of the photovoltaic module including the solar cell can be improved. From a macroscopic perspective, the velvet surface is an overall flat and long-range consistent surface, that is, the second surface 14 is a macroscopic flat surface, which is conducive to making the connection tension between each part of the electrode structure 13 and the interconnection member uniform. At the same time, when the contact surface between the interconnection member and the electrode structure 13 is a relatively flat surface, it is also conducive to making at least most of the interconnection member contact with the electrode structure 13, so that there is good contact between the two. Secondly, the height of each position of the second surface 14 increases with the increase of the height of the corresponding position of the first surface 12, and the height of each position of the second surface 14 decreases with the decrease of the height of the corresponding position of the first surface 12. Based on this, in the actual manufacturing process, while manufacturing the first surface 12 with a light-trapping function, an electrode structure 13 with corresponding undulating characteristics can be manufactured based on the first surface 12 which is a velvet surface. There is no need to perform additional velveting treatment on the conductive material for manufacturing the electrode structure 13 after depositing it in order to obtain the electrode structure 13 with a velvet surface on the second surface 14. This reduces the manufacturing difficulty of the electrode structure 13 with a velvet surface on the second surface 14 and simplifies the manufacturing process of the electrode structure 13.

[0103] Among them, in the embodiment of the present invention, if Figure 8As shown, the height of each position of the first surface 12 in the battery substrate 11 and the height of each position in the electrode structure 13 are obtained by taking the same horizontal plane as a reference standard. In addition, the corresponding position of the first surface 12 corresponding to each position of the second surface 14 mentioned above refers to: the position of the first surface 12 directly below each position of the second surface 14 along the vertical direction.

[0104] For example, the suede structure of the first surface may be a pyramid-shaped convex structure, a V-shaped groove concave structure, an inverted pyramid-shaped concave structure, a nano-hole structure, a goose eye structure or a lotus leaf structure.

[0105] In this case, since the electrode structure is formed on the first surface of the battery substrate, and the height of each position of the second surface increases with the increase of the height of the corresponding position of the first surface, and the height of each position of the second surface decreases with the decrease of the height of the corresponding position of the first surface, the type and size of the velvet structure on the first surface will not only affect its own light trapping characteristics and the bonding strength between the electrode structure and itself, but also affect the morphology of the second surface of the electrode structure formed on the battery substrate. Therefore, the type and size of the velvet structure on the first surface can be set according to the requirements of the light trapping characteristics of the first surface, the bonding strength between the battery substrate and the electrode structure, and the morphology of the second surface in the actual application scenario, as long as it can be applied to the solar cell provided in the embodiment of the present invention.

[0106] It is worth noting that when the velvet structure is a pyramid-shaped protruding structure, the above-mentioned first surface is a pyramid-shaped velvet. Based on this, since the height of each position of the second surface increases with the increase of the height of the corresponding position of the first surface, and the height of each position of the second surface decreases with the decrease of the height of the corresponding position of the first surface, the second surface is also a pyramid-shaped velvet. In this case, since the velvet structure of the pyramid-shaped velvet is a pentahedral structure, compared with the velvet structure with a smaller number of surfaces such as V-shaped grooves, the pyramid-shaped velvet structure is conducive to increasing the specific surface area of ​​the velvet, and then helping to reduce the reflectivity of the first surface; at the same time, it can also increase the contact area between the electrode structure and the first surface, and reduce the contact resistance. In addition, when the second surface is a pyramid-shaped velvet, the connection tension between the electrode structure and the interconnection can be increased, and the connection strength between the electrode structure and the interconnection can be further improved.

[0107] In addition, the specific size of the velvet structure can be determined according to the type of velvet structure and the requirements for the light trapping characteristics of the velvet in the actual application scenario. Exemplarily, the average base size of the pyramid-shaped raised structure on the first and second surfaces is greater than or equal to 0.5 μm and less than or equal to 10 μm. For example: the average base size of the pyramid-shaped raised structure on the first and second surfaces can be 0.5 μm, 1 μm, 3 μm, 6 μm, 9 μm or 10 μm, etc. In this case, the average base size of the pyramid-shaped raised structure on the first and second surfaces is within the above range, which can prevent the surface area of ​​the first and second surfaces from being smaller due to the smaller average base size of the pyramid-shaped raised structure. While ensuring that the first surface has a good light trapping effect, it ensures that the electrode structure has a larger contact area with the battery substrate, prevents the electrode structure from being separated from the battery substrate in the interconnection circuit or during the manufacturing process, and improves the stability of the electrode structure. In addition, it can also ensure that there is a larger contact area between the second surface of the electrode structure and the interconnector, ensuring that there is a stronger connection strength between the two. In addition, it is also possible to prevent the macroscopic flatness of the second surface from being reduced due to the large average tower base size of the pyramid-shaped protrusion structure, ensuring that most areas of the electrode structure can contact the interconnection member with a flat contact surface. At the same time, the larger the size of the pyramid-shaped protrusion structure, the larger the surface area of ​​the velvet surface. Therefore, when the lateral width and length of the electrode structure are the same, the larger the size of the pyramid-shaped protrusion structure, the larger the shading area of ​​the electrode structure. Based on this, the average tower base size of the pyramid-shaped protrusion structure is within the above range, and it is also possible to prevent the shading area of ​​the electrode structure from being affected by the large average tower base size of the pyramid-shaped protrusion structure, ensuring that more light can be refracted into the battery substrate through one side of the first surface.

[0108] As for the morphology of the electrode structure when the first surface is a velvet surface, the height of each position of the second surface in the electrode structure increases as the height of the corresponding position of the first surface in the battery substrate increases, and the height of each position of the second surface in the electrode structure decreases as the height of the corresponding position of the first surface in the battery substrate decreases. In other words, the second surface in the electrode structure rises and falls with the rise and fall of the first surface in the battery substrate. In addition, Figures 8 to 11As shown, the relationship between the height variation amplitude at each position of the second surface 14 of the electrode structure 13 and the height variation amplitude at the corresponding position of the first surface 12 of the battery substrate 11 is related to the thickness of the electrode structure 13. Within a certain range, the smaller the thickness of the electrode structure 13, the closer the height variation amplitude at each position of the second surface 14 of the electrode structure 13 is to the height variation amplitude at the corresponding position of the first surface 12 of the battery substrate; accordingly, the roughness of the two velvet surfaces is roughly the same. When the thickness of the electrode structure 13 is larger, there is a certain difference between the height variation amplitude at each position of the second surface 14 of the electrode structure 13 and the height variation amplitude at the corresponding position of the first surface 12 of the battery substrate; accordingly, the roughness of the two velvet surfaces is also different, but the difference is small. Among them, as Figures 9 to 11 They are respectively schematic diagrams of the structures of the second surface 14 of the 2 μm thick electrode structure 13, the 5 μm thick electrode structure 13, and the 10 μm thick electrode structure 13 when the velvet surface is a pyramid-shaped velvet surface in the embodiment of the present invention. Figures 9 to 11 It can be seen that when the surface morphology of the first surface 12 of the battery substrate is the same, the surface morphology of the second surface 14 of the electrode structures with different thicknesses is different.

[0109] As a possible implementation, Figure 8 and Fig. 9 As shown, when the thickness of the electrode structure 13 is greater than or equal to 0.5 μm and less than or equal to 15 μm, the height variation amplitude of each position of the second surface 14 and the corresponding position of the first surface 12 is substantially the same. For example: when the thickness of the electrode structure 13 is 0.5 μm, 1 μm, 5 μm, 10 μm or 15 μm, the thickness of each position of the electrode structure 13 is the same. In this case, the second surface 14 of the electrode structure 13 and the first surface 12 of the battery substrate 11 have substantially the same surface undulation characteristics, so that the second surface 14 of the electrode structure 13 can be ensured to have a larger specific surface area, so that the connection adhesion between the interconnector and the electrode structure 13 is increased, and the second surface 14 of the electrode structure 13 is ensured to be a macroscopically flat surface, which is conducive to making the connection tension between each part of the electrode structure 13 and the interconnector uniform. In other words, while the electrode structure 13 and the interconnector have a larger connection adhesion, the two also have a higher connection tension uniformity.

[0110] Exemplarily, when the thickness of the electrode structure is greater than 15 μm and less than or equal to 50 μm, the thickness of the electrode structure at the recessed position is greater than the thickness of the electrode structure at the raised position. For example: when the thickness of the electrode structure is 16 μm, 20 μm, 30 μm, 40 μm or 50 μm, the thickness of the electrode structure at the recessed position is greater than the thickness of the electrode structure at the raised position. In this case, the thickness of the electrode structure is relatively large, and the width of the electrode structure can be appropriately reduced while ensuring that the resistivity of the electrode structure remains unchanged, thereby ensuring that the electrode structure has good conductivity and current collection capabilities, while helping to reduce the shading area of ​​the electrode structure and improve the photoelectric conversion efficiency of the solar cell.

[0111] Specifically, the morphological features such as the roughness difference between the first surface of the battery substrate and the second surface of the electrode structure, the roughness of the second surface, and the thickness of the electrode structure can be determined based on the requirements for the similarity of the undulations between the first surface of the battery substrate and the second surface of the electrode structure in the actual application scenario, as well as the morphology of the velvet surface, and are not specifically limited here.

[0112] Exemplarily, the absolute value of the difference between the roughness of the first surface and the roughness of the second surface can be greater than or equal to 0.5 μm and less than or equal to 5 μm. For example: the absolute value of the difference between the roughness of the first surface and the roughness of the second surface is 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm or 5 μm, etc. In this case, the absolute value of the difference between the roughness of the first surface and the roughness of the second surface is small, that is, the difference in surface morphology between the two is small. In other words, the first surface is a conventional velvet surface of the battery substrate. Although the conventional velvet surface is microscopically convex, it is roughly flat from a macroscopic point of view, and the second surface of the electrode structure has an undulating feature that is substantially consistent with the first surface, which is conducive to making the second surface of the electrode structure also have a higher macroscopic surface flatness, which can further improve the uniformity of the connection tension between the various parts of the electrode structure and the interconnection. At the same time, it is conducive to making the second surface of the electrode structure also have a certain microscopic surface roughness, ensuring that the electrode structure and the interconnection have a higher connection strength, reducing the risk of the interconnection being detached from the electrode structure when the interconnection is connected to the circuit, and improving the structural reliability of the photovoltaic module including the solar cell.

[0113] Exemplarily, the roughness within every 10 microns of the second surface is greater than or equal to 170nm and less than or equal to 900nm, and the roughness within every 100 microns of the second surface is greater than or equal to 200nm and less than or equal to 900nm. For example: the roughness within every 10 microns of the second surface can be 180nm, 190nm, 200nm, 400nm, 500nm, 700nm or 900nm, etc., and the roughness within every 100 microns of the second surface can be 200nm, 400nm, 500nm, 700nm or 900nm, etc. In this case, when other factors are the same, the roughness of the surface is proportional to the surface area of ​​the surface. Based on this, from a microscopic perspective, the roughness within every 10 microns and every 100 microns of the second surface of the electrode structure is within the above range, which can prevent the surface area of ​​the second surface from being smaller due to the above roughness, ensuring that the electrode structure and the interconnect have a higher connection adhesion, and further reducing the risk of the interconnect being detached from the electrode structure when the interconnect is connected to the circuit. At the same time, it can also prevent the partial area of ​​the interconnection part with a relatively flat contact surface from being difficult to fully contact with the corresponding area of ​​the second surface of the electrode structure due to the high degree of unevenness of the second surface caused by the above-mentioned large roughness, thereby increasing the actual contact area between the two and ensuring good interface electrical contact between the two.

[0114] As another possible implementation, Figure 12 to Figure 14As shown, the surface on which the electrode structure 13 is formed on the battery substrate 11 is the first surface 12, and the surface of the electrode structure 13 on the side facing away from the battery substrate 11 is the second surface 14. The first surface 12 and the second surface 14 are both planes, and the roughness of the second surface 14 within every 10 microns is greater than 10nm and less than 40nm. For example: when the first surface 12 and the second surface 14 are both planes, the roughness of the second surface 14 within every 10 microns can be greater than 15nm and less than 40nm; or, the roughness of the second surface 14 within every 10 microns is greater than 20nm and less than 40nm; or, the roughness of the second surface 14 within every 10 microns is greater than 25nm and less than 40nm; or, the roughness of the second surface 14 within every 10 microns is greater than 30nm and less than 40nm. In this case, the second surface 14 that contacts the interconnector is a relatively flat surface. Because within a certain range, the surface roughness is positively correlated with the degree of unevenness of the surface, the second surface 14 of the electrode structure 13 in the present invention has a lower degree of unevenness than the electrode structure 13 with a larger outer surface roughness, so that the second surface 14 of the electrode structure 13 and the contact surface of the interconnection member have more contact points, which can increase the relative contact area between the two, and then reduce the contact resistance between the two, which is beneficial to the transmission of carriers and improves the electrical performance of the photovoltaic module including the solar cell. In addition, when the surfaces of each region of the second surface 14 of the electrode structure 13 are all relatively rough and flat, even if the actual placement position of the interconnection member on the electrode structure 13 deviates from the expected placement position during the actual manufacturing process, it can ensure that the interconnection member and the electrode structure 13 have a larger relative contact area, which can improve the interconnection consistency between the interconnection member and the electrode structure 13, and can also reduce the position accuracy requirements for placing the interconnection member on the electrode structure 13, thereby reducing the manufacturing difficulty of the photovoltaic module including the solar cell. Secondly, when the second surface 14 of the electrode structure 13 has each area surface with low roughness and flat area surface, it is also beneficial to improve the uniformity of the connection tension between each area where the interconnector contacts the electrode structure 13, and to improve the structural stability and electrical performance of the photovoltaic module. Furthermore, when the width and height of the electrode structure 13 are constant values, compared with the electrode structure 13 with an uneven outer surface, when the second surface 14 of the electrode structure 13 is a plane with low roughness and flatness, the stacking volume of the electrode structure 13 is larger, which is beneficial to reduce the on-resistance of the electrode structure 13 and improve the conductivity of the electrode structure 13.In addition, when the first surface 12 is a plane, an electrode structure 13 with corresponding surface features can be manufactured based on the flat first surface 12. There is no need to perform additional flattening treatment on the conductive material for manufacturing the electrode structure 13 after depositing it in order to obtain the electrode structure 13 with a planar outer surface. This reduces the difficulty of manufacturing the electrode structure 13 with a planar second surface 14 and simplifies the manufacturing process of the electrode structure 13.

[0115] In this case, the roughness of the second surface of the electrode structure within a range of 10 microns can be any value greater than 10 nm and less than 40 nm, and is not specifically limited here. For example, the roughness of the second surface of the electrode structure can be 11 nm, 20 nm, 25 nm, 30 nm, 35 nm or 39 nm.

[0116] As for the roughness in a large range on the second surface of the electrode structure, it can be determined by the roughness in every 10 microns on the second surface of the electrode structure and the actual application scenario. Exemplarily, the roughness in every 100 microns on the second surface can be greater than or equal to 40nm and less than 300nm. For example, the roughness in every 100 microns on the second surface can be 40nm, 100nm, 200nm, 160nm or 290nm, etc.

[0117] In addition, as mentioned above, since the electrode structure is formed on the first surface of the battery substrate, the surface morphology characteristics such as the roughness of the first surface will not only affect the bonding strength between the electrode structure and itself, but also affect the morphology of the second surface of the electrode structure formed on the battery substrate. Therefore, the surface morphology characteristics such as the roughness of the first surface can be set according to the requirements of the bonding strength between the battery substrate and the electrode structure and the morphology of the second surface in the actual application scenario, as long as they can be applied to the solar cell provided in the embodiment of the present invention.

[0118] Exemplarily, the roughness of the first surface is greater than or equal to 0 and less than or equal to 500nm. For example, the roughness of the first surface can be 0, 100nm, 200nm, 300nm, 400nm or 500nm, etc. In this case, when the electrode structure is manufactured on the first surface of the battery substrate, the surface undulation of the second surface of the electrode structure is often affected by the surface undulation of the first surface of the battery substrate. Based on this, when the first surface is a plane and the roughness of the first surface is within the above range, the first surface is a relatively flat surface, which is conducive to forming an electrode structure with a lower roughness of the second surface on the relatively flat first surface, ensuring that each area of ​​the second surface of the electrode structure has a higher flatness, further increasing the relative contact area between the electrode structure and the interconnection, and improving the uniformity of the connection tension between the electrode structure and the interconnection.

[0119] Exemplarily, the difference between the roughness of the first surface and the roughness of the second surface is greater than or equal to 20nm and less than 300nm. For example, the difference between the roughness of the first surface and the roughness of the second surface can be 20nm, 50nm, 100nm, 200nm, 240nm or 290nm, etc. In this case, when the first surface and the second surface are planes, and the difference between the roughness of the first surface and the roughness of the second surface is within the above range, the difference between the roughness of the first surface and the roughness of the second surface is small, that is, the difference in surface morphology between the two is small. In other words, the second surface of the electrode structure has a surface feature that is substantially consistent with the first surface, which is conducive to forming an electrode structure having a second surface with a higher macroscopic surface flatness on a relatively flat first surface, and can further improve the uniformity of the connection tension between the various parts of the electrode structure and the interconnection member.

[0120] Exemplarily, the surface height difference of the second surface is greater than or equal to 10nm and less than or equal to 300nm. For example, the surface height difference of the second surface can be 10nm, 10nm, 40nm, 80nm, 120nm, 160nm or 300nm, etc. In this case, in the actual application process, within a certain range, the surface height difference of the second surface is proportional to the roughness of the second surface. Among them, the smaller the surface height difference of the second surface, the more conducive to reducing the roughness of the second surface, and the larger the surface height difference of the second surface leads to an increase in the roughness of the second surface. Based on this, when the second surface is a plane and the surface height difference of the second surface of the electrode structure is within the above range, it can prevent the second surface from having poor flatness due to the large height difference of the second surface, and ensure that the contact resistance and connection tension uniformity between the electrode structure and the interconnect meet the working requirements.

[0121] In addition, in actual application, the surface of the electrode structure facing away from the battery substrate may have the same surface characteristics as the surface of the battery substrate on which the electrode structure is formed. Figures 9 to 11 ,as well as Figures 15 to 18 As shown, the surface of the electrode structure on one side facing away from the battery substrate is composed of granular conductive protrusions 15, and there is no gap between adjacent conductive protrusions 15. In this case, the granular conductive protrusions 15 are conductive structures that protrude outward relative to the main surface of the electrode structure on the side facing away from the battery substrate. Therefore, when the surface of the electrode structure on one side facing away from the battery substrate is composed of granular conductive protrusions 15, and there is no gap between adjacent conductive protrusions 15, the side of the electrode structure facing away from the battery substrate can have a larger surface area, further increasing the connection adhesion between the electrode structure and the interconnection part, and reducing the risk of the interconnection part being detached from the electrode structure when the interconnection is connected to the circuit.

[0122] Specifically, the above-mentioned granular conductive protrusions are protrusion structures formed on the main part of the electrode structure during the process of manufacturing the electrode structure; and Figures 9 to 11 ,as well as Figures 15 to 18 As shown, the size of the conductive protrusion 15 is proportional to the thickness of the electrode structure. Based on this, the distribution and size of the above-mentioned granular conductive protrusions 15 on the second surface 14 can be determined according to the manufacturing process and thickness of the electrode structure and the actual application scenario, and are not specifically limited here.

[0123] Exemplarily, the size of the above-mentioned conductive protrusion is nanometer-scale. Among them, the specific size of the conductive structure can be any size that meets the requirements of the nanometer range. For example, the size of the above-mentioned conductive protrusion can be greater than or equal to 20nm and less than or equal to 1000nm. For example, the size of the conductive protrusion can be 20nm, 100nm, 300nm, 600nm, 900nm or 1000nm, etc. In this case, the size of the conductive protrusion is within the above range, which can prevent the surface area of ​​the electrode structure away from the battery substrate from increasing significantly due to the small size of the conductive protrusion, ensure that the electrode structure and the interconnection have a high connection adhesion, and further improve the connection strength between the electrode structure and the interconnection. At the same time, it can also prevent the conductive protrusion from being too large and causing the macroscopic surface flatness of the second surface to be affected by the conductive protrusion and reduced, ensuring that the parts of the electrode structure and the interconnection have a high connection tension uniformity, and ensuring that the interconnection and the electrode structure have good contact.

[0124] Secondly, if Fig.19 and Fig. 20 As shown, the electrode structure 13 is a solid structure without pores. Of course, in some examples, during the manufacturing process of the actual electrode structure, there may be a structure with a small number of micro pores in the electrode structure. Alternatively, this is because there may be impurities and air leakage in the process chamber during the manufacturing process of the electrode structure 13. The pores are different from the pores generated by the volatilization of organic materials in the electrode slurry during the sintering process when the screen-printed electrode is manufactured.

[0125] It can be understood that when the electrode structure in the solar cell provided in the embodiment of the present invention is manufactured by vacuum coating, the materials used to manufacture the electrode structure do not include volatile organic materials used in the manufacture of silk-screen electrodes; and the chamber cleanliness of the electrode structure in the solar cell provided in the embodiment of the present invention is high and there is no air leakage, which is conducive to making the manufactured electrode structure free of pores.

[0126] In the case where the electrode structure is a solid structure without pores, such as Figures 19 to 21As shown, compared with the existing electrode structure with pores 20, each partial region of the electrode structure 13 in the embodiment of the present invention can effectively conduct carriers, which is conducive to improving the conductivity of each partial region of the electrode structure 13. At the same time, the mechanical strength of the electrode structure 13 can also be improved, reducing the risk of problems such as breakage or bending of the electrode structure 13 during the interconnection process with the interconnector or during actual use.

[0127] Among them, the internal characteristics of the electrode structure can be determined according to manufacturing parameters such as the deposition rate of the electrode structure, and the type of manufacturing process, etc., and are not specifically limited here.

[0128] In a second aspect, an embodiment of the present invention further provides a photovoltaic module, which includes the solar cell provided by the first aspect and various implementations thereof.

[0129] The beneficial effects of the second aspect in the embodiments of the present invention can be analyzed by referring to the beneficial effects of the first aspect and its various implementation methods, and will not be described in detail here.

[0130] In a third aspect, an embodiment of the present invention further provides a method for manufacturing a solar cell, the method for manufacturing a solar cell comprising: first, forming a polymer mask provided with an electrode pattern. Next, transferring and fixing the polymer mask on a battery substrate. Next, under the protection of the polymer mask, forming an electrode structure on the battery substrate by vacuum coating. The electrode structure comprises a plurality of electrodes, each electrode having a main body and continuous transition portions located on both sides of the main body along the width direction. The average height of the main body is greater than the average height of the continuous transition portion, and the boundary of the continuous transition portion away from the main body is roughly parallel to the boundary of the main body.

[0131] Specifically, the polymer mask provided with the electrode pattern can be formed by laser etching or the like. Among them, because laser etching has a high etching accuracy, when the polymer mask is formed by laser etching, the accuracy of the electrode pattern provided in the polymer mask layer can be improved, thereby improving the manufacturing accuracy of the electrode structure. In addition, the material of the polymer mask can include at least one polymer material such as PET, PMMA or PDMS that can be applied to the manufacturing method provided in the embodiment of the present invention. Secondly, after the polymer mask is transferred to the first surface of the battery substrate, the polymer mask can be fixed to the battery substrate by a combination of one or more of double-sided tape, glue, a fixed card slot, and a wafer stage. Among them, the area of ​​the battery substrate exposed outside the polymer mask is the area where the electrode structure is desired to be formed.

[0132] Furthermore, the above-mentioned vacuum coating method may include processes such as evaporation, sputtering, ion plating or vacuum winding coating. Based on this, at least one coating process included in the vacuum coating method can be used to form an electrode structure on the first side of the battery substrate. Information such as the structure of the electrode structure and the morphology of the electrode structure can be referred to the previous text and will not be repeated here. As for the process parameters when forming the electrode structure, in the actual manufacturing process, the size of the coating parameters that affect the morphology of the electrode structure can be adjusted to achieve the morphology of the second side of the manufactured electrode structure according to the requirements of the actual application scenario. Specifically, the parameters that can regulate the morphology of the second side of the electrode structure include deposition rate, etc., and the size of the above-mentioned control parameters can be determined according to actual needs.

[0133] Exemplarily, the deposition rate of the electrode structure formed on the first surface by the vacuum coating method can be greater than 0 and less than or equal to 1nm / s. For example, the deposition rate can be 0.1nm / s, 0.2nm / s, 0.4nm / s, 0.6nm / s, 0.8nm / s or 1nm / s, etc. In this case, in the actual manufacturing process, within a certain range, the deposition rate is proportional to the deposition defects. Therefore, when the deposition rate of the electrode structure on the battery substrate is within the above range, the deposition rate of the electrode structure on the battery substrate is small, which is conducive to reducing the defects in the manufactured electrode structure, and further conducive to forming a continuous transition portion continuously distributed along the length direction of the electrode on both sides of the width direction of the main body of each electrode, while ensuring that the boundary of the continuous transition portion away from the main body is roughly parallel to the boundary of the main body, thereby improving the yield of the electrode structure.

[0134] In the above description, the technical details of the patterning and etching of each layer are not described in detail. However, those skilled in the art should understand that various technical means can be used to form layers, regions, etc. of desired shapes. In addition, in order to form the same structure, those skilled in the art can also design methods that are not completely the same as the methods described above. In addition, although the various embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage.

[0135] The embodiments of the present disclosure are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, a person skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A solar cell, characterized in that: include: A battery substrate, and an electrode structure formed on the battery substrate; wherein, The electrode structure includes multiple electrodes, each electrode has a main body and continuous transition parts located on both sides of the main body along the width direction; the average height of the main body is greater than the average height of the continuous transition part, and the boundary of the continuous transition part away from the main body is roughly parallel to the boundary of the main body.

2. The solar cell according to claim 1, characterized in that The width of the continuous transition portion is greater than or equal to 0.5 μm and less than or equal to 15 μm; and / or, The angle between the surface of the continuous transition portion away from the main body and the horizontal plane is greater than or equal to 10° and less than 90°; and / or, Along the width direction of the main body and away from the main body, the height of each position of the continuous transition portion gradually decreases.

3. The solar cell according to claim 1, characterized in that The surface on which the electrode structure is formed on the battery substrate is the first surface, and the surface on the side of the electrode structure facing away from the battery substrate is the second surface; the first surface and the second surface are both velvet surfaces, and the height of each position of the second surface increases as the height of the corresponding position of the first surface increases, and the height of each position of the second surface decreases as the height of the corresponding position of the first surface decreases.

4. The solar cell according to claim 3, characterized in that: When the thickness of the electrode structure is greater than or equal to 0.5 μm and less than or equal to 15 μm, the thickness of the electrode structure at each position is the same; When the thickness of the electrode structure is greater than 15 μm and less than or equal to 50 μm, the thickness of the electrode structure at the recessed position is greater than the thickness of the electrode structure at the raised position.

5. The solar cell according to claim 3, characterized in that: The suede surface is a pyramid-shaped suede surface.

6. The solar cell according to claim 3, characterized in that: The roughness within every 10 micrometers of the second surface is greater than or equal to 170nm and less than or equal to 900nm; the roughness within every 100 micrometers of the second surface is greater than or equal to 200nm and less than or equal to 900nm; and / or, An absolute value of a difference between the roughness of the first surface and the roughness of the second surface is greater than or equal to 0.5 μm and less than 5 μm.

7. The solar cell according to claim 1, characterized in that The surface on which the electrode structure is formed on the battery substrate is the first surface, and the surface on the side of the electrode structure facing away from the battery substrate is the second surface; the first surface and the second surface are both planes, and the roughness within every 10 microns of the second surface is greater than 10nm and less than 40nm.

8. The solar cell according to claim 7, characterized in that: The roughness of the first surface is greater than or equal to 0 and less than 500 nm; and / or, The roughness of the second surface within every 100 micrometers is greater than or equal to 40 nm and less than 300 nm; and / or, The difference between the roughness of the first surface and the roughness of the second surface is greater than or equal to 20 nm and less than 300 nm; and / or, The surface height difference of the second surface is greater than or equal to 10 nm and less than or equal to 300 nm.

9. The solar cell according to claim 1, characterized in that: A surface of the electrode structure facing away from the battery substrate is composed of granular conductive protrusions, and there is no gap between adjacent conductive protrusions.

10. The solar cell according to claim 9, characterized in that: The size of the conductive protrusion is greater than or equal to 100 nm and less than or equal to 2000 nm.

11. The solar cell according to any one of claims 1 to 10, characterized in that: The electrode structure comprises a collector electrode and a bus electrode which are integrally formed and cross-arranged.

12. A photovoltaic module, characterized in that: The invention comprises a solar cell as claimed in any one of claims 1 to 11.

13. A method for manufacturing a solar cell, characterized in that: include: forming a polymer mask provided with an electrode pattern; Transferring and fixing the polymer mask on a battery substrate; Under the protection of the polymer mask, an electrode structure is formed on the battery substrate by vacuum coating; the electrode structure includes a plurality of electrodes, each electrode having a main body and continuous transition parts located on both sides of the main body along the width direction; the average height of the main body is greater than the average height of the continuous transition part, and the boundary of the continuous transition part away from the main body is roughly parallel to the boundary of the main body.

14. The method for manufacturing a solar cell according to claim 13, characterized in that: The deposition rate of forming the electrode structure on the battery substrate by the vacuum coating method is greater than 0 and less than or equal to 1 nm / s.

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