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 increase the contact area between an electrode structure and an interconnection piece included in the solar cell, increase the interconnection adhesive force and further improve the connection strength between the interconnection piece and the electrode structure. And the structural stability of the photovoltaic module comprising the solar cell can be improved. The solar cell comprises a cell substrate and an electrode structure formed on the cell substrate. The surface on which the electrode structure is formed on the battery substrate is a first surface, and the surface of one side, deviating from the battery substrate, of the electrode structure is a second surface. Wherein the first surface and the second surface are both planes, and the roughness in the second surface is larger than 10 nm and smaller than 40 nm within the range of every 10 microns; or, both the first surface and the second surface are suede surfaces, and the roughness in the second surface within the range of 10 microns is larger than or equal to 170 nm and smaller than or equal to 900 nm.

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. As global energy consumption continues to increase, people are gradually realizing the need to find new, renewable energy to replace traditional non-renewable resources such as coal and oil. Solar energy, as an energy source with great potential, is widely favored.

[0003] However, the connection strength between the electrode structure included in the existing solar cell and the interconnection members such as the welding ribbon is relatively low, resulting in poor stability of the photovoltaic module including the solar cell. Summary of the invention

[0004] The object of the present invention is to provide a solar cell and a method for manufacturing the same, and a photovoltaic module, which are used to increase the contact area between the electrode structure included in the solar cell and the interconnection part, increase the interconnection adhesion, and further improve the connection strength between the interconnection part and the electrode structure, which is beneficial to improving the structural stability of the photovoltaic module including the solar cell.

[0005] In order to achieve the above-mentioned object, in the first aspect, the present invention provides a solar cell, which comprises: a cell substrate, and an electrode structure formed on the cell substrate. The surface on which the electrode structure is formed on the cell substrate is the first surface, and the surface on the side of the electrode structure facing away from the cell substrate is the second surface. Wherein, both the first surface and the second surface are planes, and the roughness within every 10 microns of the second surface is greater than 10nm and less than 40nm; or, both the first surface and the second surface are velvet, and the roughness within every 10 microns of the second surface is greater than or equal to 170nm and less than or equal to 900nm.

[0006] In the case of adopting the above technical solution, in the actual application process, it is necessary to connect multiple solar cells in series to form a solar cell string through interconnectors such as welding strips, 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 (i.e., the second surface of the electrode structure). In this case, the second surface of the electrode structure is a plane, and the roughness within every 10 microns of the second surface is greater than 10nm and less than 40nm; at this time, compared with the electrode structure formed by the electroplating process and the roughness within every 10 microns of the second surface is less than or equal to 10nm, the roughness of the second surface of the electrode structure in the present invention that contacts the interconnector is relatively high. In addition, the second surface of the electrode structure can also be a velvet surface, and the roughness within every 10 microns of the second surface is greater than or equal to 170nm and less than or equal to 900nm; at this time, compared with the electrode structure formed by the electroplating process and the roughness within every 10 microns of the second surface is less than 170nm, the roughness of the second surface of the electrode structure in the present invention that contacts the interconnector is also relatively high. In the above case, because the surface roughness is positively correlated with the surface area of ​​the surface within a certain range, the surface area of ​​the second surface of the electrode structure in the present invention is larger than that of the electrode structure manufactured by the electroplating process, so that the contact area between the second surface of the electrode structure and the contact surface of the interconnection is larger, the connection adhesion between the interconnection and the electrode structure is increased, the connection strength between the two is improved, and finally the structural stability of the photovoltaic module including the solar cell is improved. From a macroscopic perspective, the plane is a flat surface, and the velvet surface is an overall flat and long-range consistent surface, that is, whether the second surface of the electrode structure is a plane or a velvet surface, the second surface of the electrode structure is a macroscopic flat surface, which is conducive to making the connection tension between each part of the electrode structure and the interconnection uniform, and is conducive to improving the structural stability and electrical performance of the photovoltaic module. At the same time, when the contact surface between the interconnection and the electrode structure is a relatively flat surface, it is also conducive to making at least most of the area of ​​the interconnection able to contact with the electrode structure, so that there is good contact between the two, which is conducive to reducing the on-resistance of the electrode structure and improving the conductivity of the electrode structure.

[0007] As a possible implementation manner, when the first surface is a plane, the roughness of the first surface is greater than or equal to 0 and less than 500 nm.

[0008] 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 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.

[0009] As a possible implementation manner, 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.

[0010] In the case of adopting the above technical solution, when 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.

[0011] As a possible implementation manner, when the second surface is a plane, the surface height difference of the second surface is greater than or equal to 10 nm and less than or equal to 300 nm.

[0012] 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, the surface height difference of the second surface of the electrode structure is within the above range, which 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.

[0013] As a possible implementation, when the second surface is a plane, the roughness of the second surface within every 100 microns is greater than or equal to 40 nm and less than 300 nm. 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 10 nm and less than 40 nm described above, which will not be repeated here.

[0014] As a possible implementation scheme, when both the first surface and the second surface are velvet surfaces, the roughness of the second surface within every 100 micrometers is greater than or equal to 200 nm and less than or equal to 900 nm.

[0015] 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 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 small roughness, ensure that the electrode structure and the interconnection have a high connection adhesion, and further reduce the risk of the interconnection being detached from the electrode structure when the interconnection is connected to the circuit. At the same time, it can also prevent the partial area of ​​the interconnection 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 large roughness, thereby increasing the actual contact area between the two and ensuring good interface electrical contact between the two.

[0016] 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.

[0017] 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.

[0018] As a possible implementation scheme, when both the first surface and the second surface are velvet, 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.

[0019] When the above technical solution is adopted, in the actual manufacturing process, while manufacturing the first surface with a light-trapping function, an electrode structure with corresponding undulating characteristics can be manufactured based on the first surface which is a velvet surface. There is no need to perform additional velveting treatment on the conductive material after depositing the electrode structure in order to obtain the electrode structure with a velvet surface on the second surface. This reduces the manufacturing difficulty of the electrode structure with a velvet surface on the second surface and simplifies the manufacturing process of the electrode structure.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] As a possible implementation, the electrode structure includes 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.

[0025] 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.

[0026] As a possible implementation manner, a boundary of the continuous transition portion away from the main body portion is substantially parallel to a boundary of the main body portion.

[0027] When the above technical solution is adopted, the widths of the various parts of the continuous transition section along the length direction are roughly the same, so that the continuous transition section can improve the adhesion of the various parts of the electrode along the length direction on the surface of the electrode base to roughly the same extent, thereby ensuring the structural stability of the various parts of the electrode along the length direction; at the same time, the continuous transition section can also improve the conductivity of the various parts of the electrode to roughly the same extent, so that the various parts of the electrode have roughly the same carrier collection capacity, which is beneficial for the solar cell to have a balanced number of carriers in each part of the battery base 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] As a possible implementation, the electrode structure includes a collector electrode and a bus electrode that are integrally formed and cross-arranged.

[0033] 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, so that there will be no insulating layer byproducts generated by the step-by-step manufacturing between the collector electrode and the bus electrode, eliminating the interface resistance between the collector electrode and the bus electrode, which is beneficial to the conduction of carriers between the two, and then it is beneficial to improve the electrical performance of solar cells.

[0034] As a possible implementation, the electrode structure is a solid structure without pores. In this case, each region of the electrode structure can effectively conduct carriers, which is conducive to improving the conductivity of each region 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.

[0035] In a second aspect, the present invention also provides another solar cell, which includes a cell substrate and an electrode structure formed on the cell substrate. The surface of the electrode structure facing away from the cell substrate is composed of granular conductive protrusions, and there is no gap between adjacent conductive protrusions.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] As a possible implementation scheme, the electrode structure includes 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. The analysis of the beneficial effects in this case can be referred to the above, and will not be repeated here.

[0040] As a possible implementation scheme, the boundary of the continuous transition portion away from the main body is substantially parallel to the boundary of the main body. The beneficial effect analysis in this case can be referred to in the above text, and will not be repeated here.

[0041] 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. The beneficial effect analysis in this case can be referred to above and will not be repeated here.

[0042] 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°. The analysis of the beneficial effects in this case can be referred to above and will not be repeated here.

[0043] As a possible implementation scheme, 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. The beneficial effect analysis in this case can be referred to the above, and will not be repeated here.

[0044] As a possible implementation scheme, the electrode structure includes a collector electrode and a bus electrode that are integrally formed and cross-arranged. The beneficial effect analysis in this case can be referred to the above, and will not be repeated here.

[0045] In a third aspect, the present invention further provides a photovoltaic module, which includes the solar cell provided by the first aspect and its various implementations, or includes the solar cell provided by the second aspect and its various implementations.

[0046] For the beneficial effects of the third aspect of the present invention, reference may be made to the beneficial effects analysis of the first aspect and its various implementations or the beneficial effects analysis of the second aspect and its various implementations, and will not be repeated here.

[0047] In a fourth aspect, the present invention further 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 surface of the electrode structure facing away from the battery substrate is the second surface.

[0048] The first surface and the second surface are both planes, and the roughness of the second surface within a range of 10 microns is greater than 10 nm and less than 40 nm; or, the first surface and the second surface are both velvet surfaces, and the roughness of the second surface within a range of 10 microns is greater than or equal to 170 nm and less than or equal to 900 nm;

[0049] and / or,

[0050] The second surface of the electrode structure is composed of granular conductive protrusions, and there is no gap between adjacent conductive protrusions.

[0051] The beneficial effects of the fourth aspect of the present invention can refer to the beneficial effects analysis in the first aspect and its various implementations and the beneficial effects analysis in the second aspect and its various implementations, and will not be repeated here. In addition, it should be noted that the manufacturing method provided by the present invention adopts a vacuum coating method to realize the manufacture of the electrode structure. At this time, the electrode structure can be manufactured by using metal conductive materials such as copper or aluminum whose price is lower than silver, so as to control the manufacturing cost of the electrode structure. In addition, in the process of forming the electrode structure by vacuum coating, water and other liquids will not be contacted throughout the process, so there is no need to treat wastewater. Furthermore, the polymer mask and the battery substrate are in contact through chemical bonds such as van der Waals forces or hydrogen bonds, so that the contact sealing between the two is higher, so that the situation of slurry penetration due to the loose contact between the silk screen screen and the battery substrate can be solved, and the manufacturing accuracy of the electrode structure can be improved. Moreover, after the electrode structure is formed, the polymer mask can be directly removed by mechanical means, without the need to remove the mask by chemical corrosion, which will affect the electrode structure, ensuring that the electrode structure has a higher formation quality.

[0052] As a possible implementation, 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.

[0053] 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 reduce the defects in the manufactured electrode structure, and further facilitates the formation of an electrode structure with a relatively high roughness on the battery substrate, ensuring that the contact resistance between the electrode structure and the interconnection is low and the connection tension is more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] 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:

[0055] Figure 1 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;

[0056] Figure 2 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;

[0057] Figure 3is 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;

[0058] Figure 4 A longitudinal cross-sectional schematic diagram of a partial structure of a solar cell in an embodiment of the present invention;

[0059] Figure 5 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;

[0060] Figure 6 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;

[0061] Figure 7 It is a schematic diagram of the structure enlargement 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;

[0062] Figure 8 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;

[0063] Fig. 9 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;

[0064] Fig.10 It is an enlarged longitudinal cross-sectional schematic diagram of a first structure of an electrode structure in an embodiment of the present invention;

[0065] Fig.11 It is an enlarged longitudinal cross-sectional schematic diagram of the second structure of the electrode structure in the embodiment of the present invention;

[0066] Fig.12 It is an enlarged longitudinal cross-sectional schematic diagram of a third structure of the electrode structure in an embodiment of the present invention;

[0067] Fig.13 It is a top view enlarged schematic diagram of an electrode structure in the related art;

[0068] Fig.14 It is an enlarged schematic top view of a fourth structure of the electrode structure in an embodiment of the present invention;

[0069] Fig.15 It is an enlarged longitudinal cross-sectional schematic diagram of a fifth structure of the electrode structure in an embodiment of the present invention;

[0070] Fig.16 It is an enlarged longitudinal cross-sectional schematic diagram of a sixth structure of the electrode structure in an embodiment of the present invention;

[0071] Fig.17It is an enlarged schematic diagram of a longitudinal cross-section of an electrode structure in the related art;

[0072] Fig.18 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;

[0073] Fig.19 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;

[0074] Fig. 20 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;

[0075] Fig.21 It is an enlarged schematic top view of an electrode structure in an embodiment of the present invention when the first surface and the second surface are planes.

[0076] 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

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] Photovoltaic solar cells are devices that directly convert light energy into electrical energy through the photoelectric effect. As global energy consumption continues to increase, people are gradually realizing the need to find new, renewable energy to replace traditional non-renewable resources such as coal and oil. Solar energy, as an energy source with great potential, is widely favored.

[0083] In the actual manufacturing process, the electroplating process can be used instead of the screen printing process to form the electrode structure on the battery substrate to reduce the amount of silver paste used, which is conducive to controlling the manufacturing cost of the electrode structure; at the same time, it can prevent the high-temperature sintering process from damaging the battery substrate. However, the roughness of the upper surface of the electrode structure formed on the battery substrate by the electroplating process is relatively small. When the lateral width and length are fixed, the surface area of ​​the electrode structure with a smaller surface roughness is also smaller, so that when different solar cells are interconnected to form a photovoltaic module, the contact area between the interconnection parts such as the interconnection ribbon and the electrode structure is small, resulting in a smaller interconnection adhesion between the two, and then in the subsequent lamination packaging and use process, it is easy to fall off and other risks, resulting in poor structural stability of the photovoltaic module.

[0084] 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, passivated emitter and rear contact) battery, an HJT (Heterojunction Technology, heterojunction technology) battery, an SE (selective emitter, selective emission) battery, a TOPcon (Tunnel Oxide Passivated Contact solar cell, 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.

[0085] Specifically, the solar cell comprises: a cell substrate and an electrode structure formed on the cell substrate. The surface of the cell substrate on which the electrode structure is formed is the first surface, and the surface of the electrode structure facing away from the cell substrate is the second surface. Figures 1 to 3 As shown, 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 10 nm and less than 40 nm. Figures 4 to 7 As shown, both the first surface 12 and the second surface 14 are velvet surfaces, and the roughness of the second surface 14 within every 10 micrometers is greater than or equal to 170 nm and less than or equal to 900 nm.

[0086] In the case of adopting the above technical solution, in the actual application process, it is necessary to connect multiple solar cells in series to form a solar cell string through interconnectors such as welding strips, 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 (that is, the second surface of the electrode structure). In this case, the second surface of the electrode structure is a plane, and the roughness within every 10 microns of the second surface is greater than 10nm and less than 40nm; at this time, compared with the electrode structure formed by the electroplating process and the roughness within every 10 microns of the second surface is less than or equal to 10nm, the roughness of the second surface of the electrode structure in the embodiment of the present invention in contact with the interconnector is relatively high. In addition, the second surface of the electrode structure can also be a velvet surface, and the roughness within every 10 microns of the second surface is greater than or equal to 170nm and less than or equal to 900nm; at this time, compared with the electrode structure formed by the electroplating process and the roughness within every 10 microns of the second surface is less than 160nm, the roughness of the second surface of the electrode structure in the embodiment of the present invention in contact with the interconnector is also relatively high. In the above case, because the surface roughness is positively correlated with the surface area of ​​the surface within a certain range, the surface area of ​​the second surface of the electrode structure in the embodiment of the present invention is larger than that of the electrode structure manufactured by the electroplating process, so that the contact area between the second surface of the electrode structure and the contact surface of the interconnection is larger, the connection adhesion between the interconnection and the electrode structure is increased, the connection strength between the two is improved, and finally the structural stability of the photovoltaic module including the solar cell is improved. From a macroscopic perspective, the plane is a flat surface, and the velvet surface is an overall flat and long-range consistent surface, that is, whether the second surface of the electrode structure is a plane or a velvet surface, the second surface of the electrode structure is a macroscopic flat surface, which is conducive to making the connection tension between each part of the electrode structure and the interconnection uniform, and is conducive to improving the structural stability and electrical performance of the photovoltaic module. At the same time, when the contact surface between the interconnection and the electrode structure is a relatively flat surface, it is also conducive to making at least most of the area of ​​the interconnection able to contact with the electrode structure, so that there is good contact between the two, which is conducive to reducing the on-resistance of the electrode structure and improving the conductivity of the electrode structure.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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 8 As 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 Fig. 9 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 8 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.

[0097] In terms of surface morphology, the surface morphology of the second surface of the electrode structure can be determined based on the surface morphology of the first surface of the battery substrate. Figure 4As shown, the first surface 12 of the battery substrate 11 can be a velvet surface. The first surface 12 can be the light-facing surface of the battery substrate 11, or it can be the backlight surface of the battery substrate 11. The specific position of the first surface 12 on the battery substrate 11 can be determined according to the type of solar cell. For example: when the solar cell is a double-sided contact cell, the first surface 12 is the light-facing surface and / or the backlight surface of the battery substrate 11 that is a velvet surface. For another example: when the solar cell is a back-contact cell, the first surface 12 is the backlight surface, and the backlight surface is a velvet surface. In the above case, the second surface 14 of the electrode structure 13 is also a velvet surface, and the roughness within every 10 microns of the second surface 14 can be any value greater than or equal to 170nm and less than or equal to 900nm. For example: the roughness within every 10 microns of the second surface 14 can be 180nm, 190nm, 200nm, 400nm, 500nm, 700nm or 900nm, etc.

[0098] Or, if Figures 1 to 3 As shown, the first surface 12 of the battery substrate 11 can also be a plane. The first surface 12 can be the light-facing surface of the battery substrate 11, or it can be the backlight surface of the battery substrate 11. The specific position of the first surface 12 on the battery substrate 11 can be determined according to the type of solar cell. For example: when the solar cell is a double-sided contact cell, the first surface 12 is the light-facing surface and / or the backlight surface of the battery substrate 11 that is a plane. For another example: when the solar cell is a back-contact cell, the first surface 12 is the backlight surface, and the backlight surface is a plane. In the above case, the second surface 14 is also a plane, and the roughness within every 10 microns of the second surface 14 can be greater than 10nm and less than 40nm. For example, the roughness within every 10 microns of the second surface 14 may be greater than or equal to 15 nm and less than 40 nm; or, the roughness within every 10 microns of the second surface 14 may be greater than or equal to 20 nm and less than 40 nm; or, the roughness within every 10 microns of the second surface 14 may be greater than or equal to 25 nm and less than 40 nm; or, the roughness within every 10 microns of the second surface 14 may be greater than or equal to 30 nm and less than 40 nm.

[0099] Specifically, Figure 4As shown, when 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 manufacturing process, while manufacturing the first surface 12 with a light trapping function, the electrode structure 13 with corresponding undulating characteristics can be manufactured based on the first surface 12 with a velvet surface. In order to obtain the electrode structure 13 with a velvet surface on the second surface 14, it is not necessary to perform additional velveting treatment on the conductive material for manufacturing the electrode structure 13 after depositing it, thereby reducing the manufacturing difficulty of the electrode structure 13 with a velvet surface on the second surface 14 and simplifying the manufacturing process of the electrode structure 13.

[0100] It should be noted that, in the embodiments of the present invention, Figure 4 As 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.

[0101] 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.

[0102] For example: the velvet structure of the first surface can 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, etc. Among them, when the velvet structure is a pyramid-shaped convex 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 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, and then it is conducive to 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, 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.

[0103] 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.

[0104] 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 4 to 7 As 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 and the height variation amplitude at the corresponding position of the first surface 12 of the battery substrate 11 are; accordingly, the roughness of the two velvet surfaces are 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 11; accordingly, the roughness of the two velvet surfaces is also different, but the difference is small. Among them, Figures 5 to 7 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 5 to 7 It can be seen that when the surface morphology of the first surface 12 of the battery substrate 11 is the same, the surface morphology of the second surface 14 of the electrode structures 13 with different thicknesses is different.

[0105] For example, Figure 4 and Figure 5 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.

[0106] 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.

[0107] 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 in a large range on the second surface, and the thickness of the electrode structure can be determined based on the requirements for the similarity of undulations between the first surface of the battery substrate and the second surface of the electrode structure in actual application scenarios, as well as the morphology of the velvet surface, and are not specifically limited here.

[0108] 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.

[0109] Exemplarily, the roughness within every 100 microns on 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 on the second surface can be 180nm, 190nm, 200nm, 400nm, 500nm, 700nm or 900nm, etc., and the roughness within every 100 microns on 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 100 microns on 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, ensure that the electrode structure and the interconnect have a higher connection adhesion, and further reduce 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.

[0110] In actual application, Figures 1 to 3 As shown, when both the first surface 12 and the second surface 14 are planes, the roughness of the second surface 14 of the electrode structure 13 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 14 of the electrode structure 13 can be 11 nm, 20 nm, 25 nm, 30 nm, 35 nm or 39 nm, etc.

[0111] As for the roughness in a large range of the second surface of the electrode structure, it can be determined according to the roughness in every 10 microns of the second surface of the electrode structure and the actual application scenario. For example, the roughness in every 100 microns of the second surface can be greater than or equal to 40nm and less than 300nm. For example, the roughness in every 100 microns of the second surface can be 40nm, 100nm, 200nm, 160nm or 290nm, etc.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] In addition, in actual application, the electrode structure includes multiple electrodes. Specifically, when the electrode structure includes only a collector electrode, the multiple electrodes are multiple collector electrodes. When the electrode structure includes a collector electrode and a bus electrode, the multiple electrodes include multiple collector electrodes and multiple bus electrodes, and each electrode is a collector electrode or a bus electrode. In the above case, Figures 10 to 12 As shown in FIG. 1 , each electrode may also have 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 portions 19. In this case, Fig.13 As shown, compared with the existing electrode structure manufactured by screen printing process, due to the poor sealing between the screen printing screen and the battery substrate 11, there are some discrete conductive residues formed due to part of the conductive paste entering the gap between the two. Fig.14 As shown, each electrode in the embodiment of the present invention has continuous transition portions 19 on both sides along the width direction, and the continuous transition portion 19 is a transition portion without interruption, and the continuous transition portion 19 is continuous and uninterrupted along the width direction and the length direction of the electrode. Based on this, the continuous transition portion 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.

[0117] Specifically, Fig.14 As shown, the boundary of the continuous transition portion 19 away from the main body 18 can be roughly parallel to the boundary of the main body 18. When the angle between the boundary of the continuous transition portion 19 away from the main body 18 and the boundary of the main body 18 is greater than 0 and less than or equal to A° (A° can be 5°, for example), it can be considered that 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. In this case, along the length extension direction of each electrode, the width of each part of the continuous transition portion 19 is roughly the same, so that the continuous transition portion 19 is the electrode. The degree of improvement in the adhesion of each part of the electrode along the length direction on the surface of the electrode substrate is roughly the same, ensuring the structural stability of each part of the electrode along the length direction; at the same time, it can also make the degree of improvement in the conductivity of each part of the continuous transition portion 19 to the electrode be roughly the same, so that each part of the electrode has roughly the same carrier collection ability, which is conducive to making each part of the battery substrate 11 of the solar cell 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.

[0118] Of course, the boundary of the continuous transition portion away from the main body may not be substantially parallel to the boundary of the main body. In this case, the angle between the boundary of the continuous transition portion away from the main body and the boundary of the main body can be determined according to the actual application scenario, and is not specifically limited here.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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 10 to 12As 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.

[0123] 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, which can be: the rate of change of the height gradually decreases is approximately the same. Alternatively, along the width direction of the main body and in the direction away from the main body, the rate of change of the height of some areas of the continuous transition portion is approximately the same, while the height of the remaining areas decreases significantly. For example: the rate of change of the height of the area adjacent to the main body of the continuous transition portion is approximately the same, while the height of the part that is more than a preset distance away from the main body decreases significantly.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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 shading area of ​​the electrode from being larger due to the larger width, thereby ensuring that the solar cell has a higher photoelectric conversion efficiency.

[0129] 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.

[0130] Secondly, if Fig.15 and Fig.16 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. 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.

[0131] 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.

[0132] In the case where the electrode structure is a solid structure without pores, such as Figures 15 to 17 As 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.

[0133] 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.

[0134] In a second aspect, an embodiment of the present invention further provides another solar cell. The solar cell includes a cell substrate and an electrode structure formed on the cell substrate. Figures 5 to 7 ,as well as Figures 18 to 21 As shown, the surface of the electrode structure 13 facing away from the battery substrate 11 is composed of granular conductive protrusions 15 , and there is no gap between adjacent conductive protrusions 15 .

[0135] Among them, the structure and material of the battery substrate, and the specific structure and surface morphology of the electrode structure in the second aspect can refer to the structure and material of the battery substrate, and the specific structure and surface morphology of the electrode structure in the first aspect, and will not be repeated here.

[0136] When the above technical solution is adopted, Figures 5 to 7 ,as well as Figures 18 to 21 As shown, the granular conductive protrusions 15 are conductive structures that protrude outward relative to the main surface of the electrode structure 13 on the side facing away from the battery substrate 11. Therefore, when the surface of the electrode structure 13 on the side facing away from the battery substrate 11 is composed of granular conductive protrusions 15 and there is no gap between adjacent conductive protrusions 15, the side of the electrode structure 13 facing away from the battery substrate 11 can have a larger surface area, further increasing the connection adhesion between the electrode structure 13 and the interconnection, and reducing the risk of the interconnection being detached from the electrode structure 13 when the interconnection is connected to the circuit.

[0137] 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 are randomly arranged at one side of the second surface; and Figures 5 to 7 ,as well as Figures 18 to 21 As shown, the size of the conductive protrusion 15 is proportional to the thickness of the electrode structure 13. Based on this, the distribution and size of the granular conductive protrusions 15 on the second surface 14 can be determined according to the manufacturing process and thickness of the electrode structure 13 and the actual application scenario, and are not specifically limited here.

[0138] 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.

[0139] In a third aspect, an embodiment of the present invention further provides a photovoltaic assembly, which includes the solar cell provided by the first aspect and various implementations thereof, or includes the solar cell provided by the second aspect and various implementations thereof.

[0140] For the beneficial effects of the third aspect in the embodiments of the present invention, reference can be made to the analysis of the beneficial effects in the first aspect and its various implementations and the analysis of the beneficial effects in the second aspect and its various implementations, which will not be repeated here.

[0141] In a fourth aspect, an embodiment of the present invention further 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, vacuum coating is used to form an electrode structure on the battery substrate. The surface of the electrode structure facing away from the battery substrate is the second surface.

[0142] like Figures 1 to 3 As shown, 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 10 nm and less than 40 nm; or Figures 4 to 7 As shown, the first surface 12 and the second surface 14 are both velvet surfaces, and the roughness of the second surface 14 within every 10 microns is greater than or equal to 170nm and less than or equal to 900nm;

[0143] and / or,

[0144] like Figures 5 to 7 ,as well as Figures 18 to 21As shown, the second surface 14 of the electrode structure 13 is composed of granular conductive protrusions 15 , and there is no gap between adjacent conductive protrusions 15 .

[0145] Specifically, a polymer mask provided with an 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 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.

[0146] 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 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 side of the electrode structure away from the battery substrate can be adjusted to achieve the morphology of the manufactured electrode structure away from the battery substrate according to the requirements of the actual application scenario. Specifically, the parameters that can regulate the morphology of the electrode structure away from the battery substrate include deposition rate, etc., and the size of the above-mentioned control parameters can be determined according to actual needs.

[0147] Exemplarily, 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 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 then it is conducive to forming an electrode structure with a relatively high roughness on the battery substrate, ensuring that the contact resistance between the electrode structure and the interconnection is low and the connection tension is more uniform.

[0148] The beneficial effects of the fourth aspect of the embodiment of the present invention can refer to the beneficial effects analysis of the first aspect and its various implementations and the second aspect and its various implementations, and will not be repeated here. In addition, it should be noted that the manufacturing method provided by the embodiment of the present invention adopts a vacuum coating method to realize the manufacture of the electrode structure. At this time, the electrode structure can be manufactured by using metal conductive materials such as copper or aluminum whose price is lower than silver, so as to control the manufacturing cost of the electrode structure. In addition, in the process of forming the electrode structure by vacuum coating, water and other liquids will not be contacted throughout the process, so there is no need to treat wastewater. Furthermore, the polymer mask and the battery substrate are in contact through chemical bonds such as van der Waals forces or hydrogen bonds, so that the contact sealing between the two is higher, so that the situation of slurry penetration due to the loose contact between the silk screen screen and the battery substrate can be solved, and the manufacturing accuracy of the electrode structure can be improved. Moreover, after the electrode structure is formed, the polymer mask can be directly removed by mechanical means, without the need to remove the mask by chemical corrosion, which will affect the electrode structure, ensuring that the electrode structure has a high formation quality.

[0149] 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.

[0150] 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; The surface of the battery substrate on which the electrode structure is formed is the first surface, and the surface of the electrode structure on the side away from the battery substrate is the second surface; wherein, Both the first surface and the second surface are planes, and the roughness of the second surface within every 10 microns is greater than 10 nm and less than 40 nm; or, both the first surface and the second surface are velvet surfaces, and the roughness of the second surface within every 10 microns is greater than or equal to 170 nm and less than or equal to 900 nm.

2. The solar cell according to claim 1, characterized in that When the first surface is a plane, the roughness of the first surface is greater than or equal to 0 and less than 500 nm; and / or, 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; and / or, When the second surface is a plane, the height difference of the second surface is greater than or equal to 10 nm and less than or equal to 300 nm; and / or, When the second surface is a plane, the roughness of the second surface per 100 micrometers is greater than or equal to 40 nm and less than 300 nm.

3. The solar cell according to claim 1, characterized in that When the second surface is a velvet surface, the roughness of the second surface within every 100 micrometers is greater than or equal to 200 nm and less than or equal to 900 nm; and / or, 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; and / or, When both the first surface and the second surface are 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.

4. The solar cell according to claim 1, characterized in that In the case where both the first surface and the second surface are velvet surfaces, 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 various positions 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 any one of claims 1 to 4, characterized in that: The electrode structure includes a plurality of electrodes, each of which has a main body and continuous transition portions located on both sides of the main body along a width direction; an average height of the main body is greater than an average height of the continuous transition portions.

6. The solar cell according to claim 5, characterized in that: The boundary of the continuous transition portion facing away from the main body portion is substantially parallel to the boundary of the main body portion.

7. The solar cell according to claim 5, 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.

8. The solar cell according to any one of claims 1 to 4, characterized in that: The electrode structure comprises a collector electrode and a bus electrode which are integrally formed and cross-arranged.

9. A solar cell, characterized in that: include: A battery substrate and an electrode structure formed on the battery substrate; 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 claim 9 or 10, characterized in that: The electrode structure includes a plurality of electrodes, each of which has a main body and continuous transition portions located on both sides of the main body along a width direction; an average height of the main body is greater than an average height of the continuous transition portions.

12. The solar cell according to claim 11, characterized in that: The boundary of the continuous transition portion facing away from the main body portion is substantially parallel to the boundary of the main body portion.

13. The solar cell according to claim 11, 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.

14. The solar cell according to claim 9 or 10, characterized in that: The electrode structure comprises a collector electrode and a bus electrode which are integrally formed and cross-arranged.

15. A photovoltaic module, characterized in that: The invention comprises a solar cell as claimed in any one of claims 1 to 8; or comprises a solar cell as claimed in any one of claims 9 to 14.

16. 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 surface of the battery substrate on which the electrode structure is formed is the first surface, and the surface of the electrode structure on the side away from the battery substrate is the second surface; wherein, The first surface and the second surface are both planes, and the roughness of the second surface within a range of 10 microns is greater than 10 nm and less than 40 nm; or, the first surface and the second surface are both velvet surfaces, and the roughness of the second surface within a range of 10 microns is greater than or equal to 170 nm and less than or equal to 900 nm; and / or, The second surface of the electrode structure is composed of granular conductive protrusions, and there is no gap between adjacent conductive protrusions.

17. The method for manufacturing a solar cell according to claim 16, characterized in that: 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.

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