Solar cell, preparation method thereof and photovoltaic module

Abstract

The invention relates to the field of solar cells, and discloses a solar cell, a preparation method thereof and a photovoltaic module. Comprising a semi-finished solar cell product and an electrode structure arranged on the semi-finished solar cell product, the semi-finished solar cell product is made of silicon, and the electrode structure comprises a contact layer, and a diffusion suppression layer and a conductive layer which are sequentially laminated on the contact layer; the material of the conductive layer comprises a first metal, the material of the diffusion inhibition layer comprises an alloy formed by the first metal and a second metal, the material of the contact layer comprises a third metal, the electronegativity difference value of the first metal and the second metal is greater than or equal to 0.2, the first metal comprises at least one of copper and aluminum, and the conductivity of the third metal is greater than that of the first metal. The solid solubility of the third metal in the silicon is smaller than that of the first metal. The electrode structure not only can effectively restrain and avoid the reaction between the first metal and silicon, but also can ensure the contact effect between the electrode structure and the semi-finished solar cell product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a solar cell, a preparation method thereof and a photovoltaic module. BACKGROUND

[0002] In the electrode structure of a solar cell, copper, aluminum and other materials are one of the ideal materials for preparing the electrode structure due to the advantages of high conductivity and low cost. However, when the above-mentioned materials are used as the electrode structure, they are easy to diffuse into the interior of the solar cell semi-finished product and react with silicon to form deep energy level defects. Such defects can cause the recombination of carriers to intensify, making it difficult to effectively improve the photoelectric conversion efficiency of the solar cell. SUMMARY

[0003] Embodiments of the present application disclose a solar cell, a preparation method thereof and a photovoltaic module. The electrode structure in the solar cell can not only effectively inhibit the diffusion of the first metal in the electrode structure into the solar cell semi-finished product and avoid the reaction of the first metal with silicon, but also ensure the contact effect of the electrode structure and the solar cell semi-finished product.

[0004] In a first aspect, embodiments of the present application disclose a solar cell, comprising a solar cell semi-finished product and an electrode structure arranged on the solar cell semi-finished product, the material of the solar cell semi-finished product comprising silicon, and the electrode structure comprising a contact layer, and a diffusion inhibition layer and a conductive layer arranged in sequence on the contact layer. The material of the conductive layer comprises a first metal, the material of the diffusion inhibition layer comprises an alloy formed by the first metal and a second metal, and the material of the contact layer comprises a third metal, wherein the electronegativity difference between the first metal and the second metal is greater than or equal to 0.2, the first metal comprises at least one of copper and aluminum, the conductivity of the third metal is greater than that of the first metal, and the solid solubility of the third metal in the silicon is less than that of the first metal.

[0005] Further, in the diffusion inhibition layer, the mass percentage content of the first metal is 45% to 90%.

[0006] Further, the first metal comprises copper, and the second metal comprises at least one of manganese, chromium and vanadium; and / or, the third metal comprises at least one of silver and gold; and / or, The material of the contact layer further comprises nickel, and the mass percentage content of the nickel in the contact layer is 1% to 30%.

[0007] Further, the end of the conductive layer has a distance from the surface of the solar cell semi-finished product. Alternatively, the end of the conductive layer is connected to the solar cell semi-finished product.

[0008] Further, the top surface and at least part of the side surface of the contact layer protrude from the surface of the solar cell semi-product; The diffusion inhibition layer comprises a first diffusion inhibition sub-layer and a second diffusion inhibition sub-layer connected to each other, the first diffusion inhibition sub-layer covers the top surface of the contact layer, and the second diffusion inhibition sub-layer is arranged at least on part of the side surface of the contact layer.

[0009] Further, the conductive layer comprises a first conductive sub-layer and a second conductive sub-layer connected to each other, the first conductive sub-layer covers the top surface of the first diffusion inhibition sub-layer; The second diffusion inhibition sub-layer covers the entire side surface of the contact layer, and the first conductive sub-layer is arranged at least on the entire side surface of the second diffusion inhibition sub-layer.

[0010] Further, the electrode structure comprises a first electrode structure arranged on the light-receiving surface of the solar cell semi-product and a second electrode structure arranged on the back surface of the solar cell semi-product, the first electrode structure comprises a first contact layer, a first diffusion inhibition layer, and a first conductive layer, and the second electrode structure comprises a second contact layer, a second diffusion inhibition layer, and a second conductive layer.

[0011] Further, the width of the first electrode structure is 5 μm to 22 μm; and / or, The thickness of the first electrode structure is 4 μm to 13 μm; and / or, The thickness of the first contact layer is 0.5 μm to 4 μm; and / or, The thickness of the first diffusion inhibition layer is 0.5 μm to 1.5 μm; and / or, The thickness of the first conductive layer is 2 μm to 5 μm; and / or, The width of the second electrode structure is 10 μm to 32 μm; and / or, The thickness of the second electrode structure is 4 μm to 11 μm; and / or, The thickness of the second contact layer is 0.5 μm to 3 μm; and / or, The thickness of the second diffusion inhibition layer is 0.5 μm to 1.5 μm; and / or, The thickness of the second conductive layer is 2 μm to 5 μm.

[0012] Further, the electrode structure further comprises a protective layer arranged on the side surface of the conductive layer away from the diffusion inhibition layer, and the oxidation resistance of the protective layer is higher than that of the conductive layer.

[0013] Further, the material of the protective layer comprises at least one of tungsten, rhenium, tantalum, molybdenum, titanium, and hafnium; and / or, The protective layer includes a first protective layer disposed on the light-receiving surface of the solar cell semi-finished product and a second protective layer disposed on the back surface of the solar cell semi-finished product, wherein the thickness of the first protective layer is 1μm~2.5μm and the thickness of the second protective layer is 0.5μm~1.5μm.

[0014] Furthermore, the solar cell is a passivated contact solar cell, the electrode structure includes a first electrode structure and a second electrode structure, and the solar cell semi-finished product includes: A silicon substrate, the silicon substrate comprising a light-receiving surface and a back-lighting surface disposed opposite to each other; A diffusion doped layer, a first functional layer, and a first electrode structure are sequentially disposed on the light-receiving surface of the silicon substrate; A passivation contact structure, a second functional layer, and a second electrode structure are sequentially disposed on the backlight surface of the silicon substrate. The passivation contact structure includes a dielectric layer and a doped silicon layer sequentially stacked on the backlight surface. Wherein, the first functional layer is a first passivation layer and / or a first antireflection layer, the second functional layer is a second passivation layer and / or a second antireflection layer, the first contact layer in the first electrode structure is in ohmic contact with the diffused doped layer, and the second contact layer in the second electrode structure is in ohmic contact with the doped silicon layer.

[0015] Secondly, embodiments of this application disclose a method for fabricating solar cells, the method comprising the following steps: A contact layer is prepared on a semi-finished solar cell, wherein the semi-finished solar cell is made of silicon. A diffusion inhibition layer is prepared on the surface of the contact layer, wherein the material of the diffusion inhibition layer includes a first metal and a second metal, the electronegativity difference between the first metal and the second metal is greater than or equal to 0.2, the first metal includes at least one of copper and aluminum, the material of the contact layer includes a third metal, the conductivity of the third metal is greater than that of the first metal, and the solid solubility of the third metal in silicon is less than that of the first metal. A conductive layer is prepared on the surface of the diffusion suppression layer, the material of the conductive layer including the first metal, to obtain a solar cell according to any one of the first aspects.

[0016] Further, the contact layer includes a first contact layer and a second contact layer, wherein the step of preparing the first contact layer includes: A paste containing the third metal is printed on the light-receiving surface of the solar cell semi-finished product and then dried. The dried slurry containing the third metal is subjected to a first sintering. The slurry containing the third metal after sintering is injected with a laser for a second sintering to obtain the first contact layer.

[0017] Furthermore, during the preparation of the first contact layer, the temperature of the first sintering is 700℃~820℃; and / or, In the second sintering step, the laser parameters include: laser wavelength of 800 nm to 1300 nm, laser spot size of 1 μm to 1.4 μm, current density of 340 A / cm² to 1800 A / cm², laser power of 40 W to 60 W, laser power density of 35 kW / cm² to 60 kW / cm², and scanning speed of 4 m / s to 7 m / s.

[0018] Further, the step of preparing the second contact layer includes: A paste containing the third metal is printed on the back surface of the solar cell semi-finished product and then dried. The dried slurry containing the third metal is subjected to a third sintering to obtain the second contact layer.

[0019] Furthermore, the drying temperature is 100℃~200℃; and / or, The temperature for the third sintering is 650℃~780℃.

[0020] Furthermore, after the step of preparing a conductive layer on the surface of the diffusion inhibition layer, the preparation method further includes: preparing a protective layer on the outside of the conductive layer, wherein the antioxidant properties of the protective layer are higher than those of the conductive layer.

[0021] Thirdly, embodiments of this application disclose a photovoltaic module, which includes the solar cell described in any of the first aspects, or the photovoltaic module further includes the solar cell prepared by the preparation method described in the second aspect.

[0022] Compared with the prior art, the beneficial effects of this application are as follows: This application discloses a solar cell and its preparation method, as well as a photovoltaic module. The electrode structure in the solar cell can effectively suppress the diffusion of the first metal in the electrode structure to the solar cell semi-finished product and avoid the reaction between the first metal and silicon, while also ensuring the contact effect between the electrode structure and the solar cell semi-finished product.

[0023] Specifically, in the electrode structure of this application, the contact layer is made of a third metal, which has higher conductivity than the first metal and lower solid solubility in silicon. Therefore, the higher conductivity helps to reduce the contact resistance between the contact layer and the solar cell semi-finished product, while the lower solid solubility increases the difficulty of the reaction between the third metal and the silicon in the solar cell semi-finished product, making it difficult for the third metal to react with silicon to form deep level defects. Furthermore, a conductive layer is provided on the outside of the contact layer. The first metal in the conductive layer includes at least one of copper and aluminum. The aforementioned metal materials have high conductivity. Therefore, with the cooperation of the contact layer and the conductive layer, the conductivity of the electrode structure can be effectively ensured, and the production cost can be reduced.

[0024] In addition, the electrode structure also includes a diffusion suppression layer located between the conductive layer and the contact layer. The diffusion suppression layer is made of an alloy formed by a first metal and a second metal. The presence of the first metal can effectively improve the conductivity of the diffusion suppression layer, thereby enabling the diffusion suppression layer to have a better contact effect with the contact layer and the conductive layer respectively. Therefore, it can play a higher transition role and help reduce the transport barrier of charge carriers between the contact layer and the conductive layer. In addition, the electronegativity difference between the first metal and the second metal in the diffusion suppression layer is greater than or equal to 0.2. Therefore, this electronegativity difference can block the diffusion of the first metal to the side of the solar cell semi-finished product, reduce the reaction probability of the first metal with silicon, and thus avoid the generation of deep level defects and avoid the recombination of charge carriers to a high extent. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the structure of a solar cell provided in an embodiment of this application; Figure 2 yes Figure 1 Enlarged schematic diagram of region A (showing the first electrode structure); Figure 3 yes Figure 1 Enlarged schematic diagram of region A (showing the second electrode structure); Figure 4 yes Figure 1 Enlarged schematic diagram of region A (showing the third electrode structure); Figure 5 yes Figure 1 Enlarged schematic diagram of region A (showing the fourth electrode structure); Figure 6 yes Figure 1 Enlarged schematic diagram of region A (showing the fifth electrode structure); Figure 7 yes Figure 1 Enlarged schematic diagram of region A (showing the sixth electrode structure).

[0027] Icons: 1. Solar cell semi-finished product; 11. Silicon substrate; 11a. Light-receiving surface; 11b. Backlighting surface; 12. Diffusion doped layer; 13. First functional layer; 131. First passivation layer; 132. First antireflection layer; 14. Passivation contact structure; 141. Dielectric layer; 142. Doped silicon layer; 15. Second functional layer; 2. Electrode structure; 2a. First electrode structure; 2b. Second electrode structure; 21. Contact layer; 21a. First contact layer; 21b. Second contact layer; 22. Diffusion suppression layer; 22a. First diffusion suppression layer; 22b. Second diffusion suppression layer; 221. First diffusion suppression sub-section; 222. Second diffusion suppression sub-section; 23. Conductive layer; 231. First conductive sub-section; 232. Second conductive sub-section; 23a. First conductive layer; 23b. Second conductive layer; 24. Protective layer; 24a. First protective layer; 24b. Second protective layer. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0030] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0031] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0032] The technical solutions provided in this application will be further described below with reference to the embodiments and accompanying drawings.

[0033] In electrode structures, silver is an ideal electrode material due to its excellent conductivity and chemical stability. However, the high cost of silver makes it difficult to effectively reduce costs. Therefore, to reduce production costs, copper or aluminum, which have high conductivity and low price, can currently be used to replace silver to achieve cost reduction.

[0034] However, silicon in solar cell semi-finished products contains defects such as vacancies and dislocations. Therefore, when copper or aluminum is used as electrode material, the high solid solubility of these materials in silicon will make their reaction with silicon more active and more likely to form deep-level defects.

[0035] Based on the above problems, this application provides a solar cell and its preparation method, as well as a photovoltaic module. The electrode structure in the solar cell can effectively suppress the diffusion of the first metal in the electrode structure to the solar cell semi-finished product and avoid the reaction between the first metal and silicon, while also ensuring the contact effect between the electrode structure and the solar cell semi-finished product.

[0036] This application discloses a solar cell, such as Figure 1 and Figure 2 As shown in the diagram, in addition, to better illustrate the structural schematic of the electrode structure, Figures 2 to 7 The specific film structure and textured surface structure of the solar cell semi-finished product are not shown in the figure. The solar cell includes a solar cell semi-finished product 1 and an electrode structure 2 disposed on the solar cell semi-finished product 1. The material of the solar cell semi-finished product 1 includes silicon. The electrode structure 2 includes: a contact layer 21, and a diffusion suppression layer 22 and a conductive layer 23 sequentially stacked on the contact layer 21. The conductive layer 23 is made of a first metal, the diffusion inhibition layer 22 is made of an alloy formed by the first metal and the second metal, and the contact layer 21 is made of a third metal. The difference in electronegativity between the first metal and the second metal is greater than or equal to 0.2. The first metal includes at least one of copper and aluminum. The conductivity of the third metal is greater than that of the first metal. The solid solubility of the third metal in silicon is less than that of the first metal.

[0037] The electronegativity of the first metal can be greater than that of the second metal, or it can be less than that of the second metal. Optionally, when the first metal is copper, the second metal includes at least one of manganese, chromium, and vanadium. When copper, which has high conductivity, is used as the material of the conductive layer 23, by selecting the above-mentioned type of second metal, it has a good anchoring effect on copper, which can effectively block the diffusion of copper to the contact layer 21 side, thereby helping to avoid the generation of deep-level defects.

[0038] Furthermore, the third metal includes at least one of silver and gold. When the above material is used as the contact layer 21, its conductivity is higher, which helps to reduce the contact resistance between the contact layer 21 and the solar cell semi-finished product 1. More preferably, when the third metal is silver, it also helps to reduce production costs, thereby further contributing to cost reduction and efficiency improvement. In addition, the material of the contact layer 21 includes the third metal and nickel. When nickel is included, the mass percentage of nickel in the contact layer 21 is 1% to 30%. By controlling the mass percentage of nickel within the above range, it is more helpful to reduce production costs while ensuring the contact performance of the contact layer 21. For example, the mass percentage of nickel is 1%, 10%, 15%, 20%, 30%, etc.

[0039] In addition, in the solar cell semi-finished product 1, silicon mainly exists in the form of atoms, and the first metal, second metal, third metal and alloy in the electrode structure 2 also exist in the form of atoms, and the atoms in the electrode structure 2 can be arranged in a regular manner to form a crystal structure.

[0040] It is worth noting that, as described above, the diffusion suppression layer 22, conductive layer 23, and contact layer 21 of this application are all crystalline structures. Therefore, compared with the contact between crystalline and amorphous structures, the contact between these crystalline film layers makes the diffusion suppression layer 22 more compatible with the conductive layer 23 and the contact layer 21, respectively, which helps to reduce defects at the interface and thus helps to reduce the recombination of charge carriers at the interface.

[0041] In the electrode structure 2 of this application, the contact layer 21 is made of a third metal. The third metal has higher conductivity than the first metal and lower solid solubility in silicon. Therefore, the higher conductivity helps to reduce the contact resistance between the contact layer 21 and the solar cell semi-finished product 1, while the lower solid solubility increases the difficulty of the reaction between the third metal and the silicon in the solar cell semi-finished product 1, making it difficult for the third metal to react with silicon to form deep energy level defects. Furthermore, a conductive layer 23 is also provided on the outside of the contact layer 21. The first metal in the conductive layer 23 includes at least one of copper and aluminum. The above-mentioned metal materials have high conductivity. Therefore, with the cooperation of the contact layer 21 and the conductive layer 23, the conductivity of the electrode structure 2 can be effectively ensured, and the production cost can be reduced.

[0042] In addition, the electrode structure 2 also includes a diffusion suppression layer 22 located between the conductive layer 23 and the contact layer 21. The diffusion suppression layer 22 is made of an alloy formed by a first metal and a second metal. The presence of the first metal can effectively improve the conductivity of the diffusion suppression layer 22, thereby enabling the diffusion suppression layer 22 to have a better contact effect with the contact layer 21 and the conductive layer 23 respectively. Therefore, it can play a higher transition role and help reduce the transport barrier of charge carriers between the contact layer 21 and the conductive layer 23. In addition, the electronegativity difference between the first metal and the second metal in the diffusion suppression layer 22 is greater than or equal to 0.2. Therefore, this electronegativity difference can block the diffusion of the first metal to the side of the solar cell semi-finished product 1, reduce the reaction probability of the first metal with silicon, and thus avoid the generation of deep level defects and avoid the recombination of charge carriers to a high extent.

[0043] In summary, by selecting specific materials for the conductive layer 23, contact layer 21, and diffusion suppression layer 22, the synergistic effect of these layers helps to avoid the reaction between the third metal in the electrode structure 2 and silicon, improves the contact performance between the contact layer 21 and the solar cell semi-finished product 1, and further helps to improve the photoelectric conversion efficiency of the solar cell.

[0044] Furthermore, the electrode structure 2 includes a main grid and a fine grid. The fine grid is a structure used to form an ohmic contact with the solar cell semi-finished product 1. The fine grid includes the aforementioned contact layer 21, diffusion suppression layer 22, conductive layer 23, and other configurations.

[0045] Furthermore, in the diffusion suppression layer 22, the mass percentage of the first metal is 45% to 90%. By controlling the proportion of the first metal within the above range, it helps to ensure that the diffusion suppression layer 22 has high conductivity and reduces the contact resistance between the diffusion suppression layer 22 and the contact layer 21 and conductive layer 23; it also effectively ensures that the diffusion suppression layer 22 has a high effect in blocking the diffusion of the first metal to the contact layer 21, thus significantly reducing the generation of deep-level defects and further improving the photoelectric conversion efficiency of the solar cell. For example, the mass percentage of the first metal is 45%, 60%, 70%, 80%, or 90%, etc.

[0046] This application can use energy dispersive spectroscopy (EDS) to determine the mass percentage content of the first metal in the conductive layer 23. This application does not limit the testing method for the first metal; any method that achieves the desired effect is acceptable.

[0047] In one alternative implementation, such as Figure 2 and Figure 3 As shown, the end of the conductive layer 23 is connected to the solar cell semi-finished product 1.

[0048] The top surface and at least part of the side surfaces of the contact layer 21 protrude from the surface of the solar cell semi-finished product 1. The diffusion suppression layer 22 includes a first diffusion suppression sub-section 221 and a second diffusion suppression sub-section 222 that are interconnected. The first diffusion suppression sub-section 221 covers the top surface of the contact layer 21, and the second diffusion suppression sub-section 222 is disposed at least on a portion of the side surface of the contact layer 21.

[0049] Furthermore, the conductive layer 23 includes a first conductive sub-part 231 and a second conductive sub-part 232 that are interconnected. The first conductive sub-part 231 covers the top surface of the first diffusion suppressor sub-part 221, the second conductive sub-part 232 is disposed on the side surface of the second diffusion suppressor sub-part 222, and the end of the second conductive sub-part 232 is connected to the solar cell semi-finished product 1.

[0050] Wherein, the second diffusion suppression sub-part 222 is provided at least on a portion of the side surface of the contact layer 21, meaning that, for example... Figure 3 As shown, the second diffusion suppression sub-part 222 is disposed on a portion of the side surface of the contact layer 21. At this time, the second conductive sub-part 232 covers all the side surfaces of the second diffusion suppression sub-part 222 and the exposed side surfaces of the contact layer 21.

[0051] Or, see the return Figure 2 The second diffusion suppression sub-section 222 is disposed on all sides of the contact layer 21, and the second conductive sub-section 232 only covers all sides of the second diffusion suppression sub-section 222. When this scheme is adopted, the diffusion suppression layer 22 has a higher blocking effect on the lateral transport of the first metal, which helps to prevent the first metal from laterally transporting into the contact layer and thus reacting with silicon to generate deep level defects.

[0052] In another alternative implementation, such as Figures 4 to 7 As shown, there is a distance between the end of the conductive layer 23 and the surface of the solar cell semi-finished product 1. In this design, the conductive layer 23 does not contact the solar cell semi-finished product 1, which helps to prevent the first metal in the conductive layer 23 from diffusing into the solar cell semi-finished product 1, and to a greater extent avoids the reaction between the first metal and silicon, thus avoiding the formation of deep energy level defects.

[0053] In this embodiment, see back Figure 4 and Figure 5 The conductive layer 23 is located on the surface of the contact layer 21 facing away from the solar cell semi-finished product 1, and there is a distance between the end of the conductive layer 23 and the surface of the solar cell semi-finished product 1. In both schemes, the distance between the end of the conductive layer 23 and the surface of the solar cell semi-finished product 1 is relatively large, thus helping to increase the difficulty of diffusion of the third metal into the solar cell semi-finished product 1. Figure 4 In the plan, Figure 4The second diffusion suppression sub-section 222 covers the entire side of the contact layer 21. This arrangement helps to prevent the first metal in the conductive layer 23 from diffusing from the side into the solar cell semi-finished product 1, and helps to suppress the generation of deep energy level defects.

[0054] The surface of the solar cell semi-finished product 1 refers to its upper or lower surface. When the electrode structure 2 is located on the light-receiving surface of the solar cell semi-finished product 1, it means that there is a distance between the end of the conductive layer 23 and the upper surface of the solar cell semi-finished product 1; when the electrode structure 2 is located on the back surface of the solar cell semi-finished product 1, it means that there is a distance between the end of the conductive layer 23 and the lower surface of the solar cell semi-finished product 1.

[0055] Additionally, see the return Figure 6 The second conductive sub-part 232 in the conductive layer 23 is disposed on the side of the second diffusion suppression sub-part 222; see back Figure 7 The second conductive sub-part 232 in the conductive layer 23 is disposed on the side of the second diffusion suppressor sub-part 222 and part of the side of the contact layer 21. This arrangement results in a larger area of ​​the conductive layer 23, which helps to further improve the conductivity of the electrode structure 2 and prevents the first metal of the conductive layer 23 from being transported into the solar cell semi-finished product.

[0056] Further, see the return Figure 1 The electrode structure 2 includes a first electrode structure 2a disposed on the light-receiving surface 11a of the solar cell semi-finished product 1, and a second electrode structure 2b disposed on the backlight surface 11b of the solar cell semi-finished product 1. The first electrode structure 2a includes a first contact layer 21a, a first diffusion suppression layer 22a, and a first conductive layer 23a. The second electrode structure 2b includes a second contact layer 21b, a second diffusion suppression layer 22b, and a second conductive layer 23b.

[0057] The width L of the first electrode structure 2a is between 5 μm and 22 μm. Controlling the width of the first electrode structure 2a within this range helps ensure the area of ​​the light-receiving surface 11a, thereby contributing to a higher degree of absorption and utilization of sunlight by the light-receiving surface 11a and improving the photoelectric conversion efficiency of the solar cell. For example, the width of the first electrode structure 2a is 5 μm, 9 μm, 14 μm, 19 μm, or 22 μm, etc.

[0058] The thickness H of the first electrode structure 2a is 4 μm to 13 μm. Controlling the thickness of the first electrode structure 2a within this range ensures both high contact performance with the solar cell semi-finished product 1 and good conductivity. For example, the thickness of the first electrode structure 2a can be 4 μm, 6 μm, 8 μm, 10 μm, or 13 μm, etc.

[0059] Furthermore, the thickness of the first contact layer 21a is 0.5 μm to 4 μm. When the thickness of the first contact layer 21a is within the above range, it helps to ensure high contact performance between it and the solar cell semi-finished product 1, and reduces the carrier transport barrier. For example, the thickness of the first contact layer 21a is 0.5 μm, 1 μm, 2 μm, 3 μm, or 4 μm, etc.

[0060] Furthermore, the thickness of the first diffusion suppression layer 22a is 0.5 μm to 1.5 μm. When the thickness of the first diffusion layer is within the above range, it can effectively ensure its blocking effect on the first metal in the first conductive layer 23a, and also ensure the contact effect between the first diffusion suppression layer 22a, the first conductive layer 23a, and the first contact layer 21a. For example, the thickness of the first diffusion suppression layer 22a is 0.5 μm, 0.7 μm, 0.9 μm, 1.1 μm, or 1.5 μm, etc.

[0061] Furthermore, the thickness of the first conductive layer 23a is 2 μm to 5 μm. When the thickness of the first conductive layer 23a is within the above range, it helps to ensure the conductivity of the first conductive structure to a higher degree, thereby further contributing to improving the photoelectric conversion efficiency of the solar cell. For example, the thickness of the first conductive layer 23a is 2 μm, 3 μm, 3.5 μm, 4 μm, or 5 μm, etc.

[0062] When the thicknesses of the first diffusion suppression layer 22a, the first conductive layer 23a, and the first contact layer 21a are all within the above-mentioned range, these three layers have a high degree of matching, which is more conducive to improving the performance of the first electrode structure 2a.

[0063] The width of the second electrode structure 2b is 10 μm to 32 μm. Controlling the width of the second electrode structure 2b within the above range helps to ensure the contact effect between the second electrode structure 2b and the backlight surface 11b. For example, the width of the second electrode structure 2b is 10 μm, 15 μm, 20 μm, 25 μm, or 32 μm, etc.

[0064] The thickness of the second electrode structure 2b is 4 μm to 11 μm. Controlling the thickness of the second electrode structure 2b within this range ensures both high contact performance with the solar cell semi-finished product 1 and good conductivity. For example, the thickness of the second electrode structure 2b can be 4 μm, 6 μm, 8 μm, 10 μm, or 11 μm, etc.

[0065] Furthermore, the thickness of the second contact layer 21b is 0.5 μm to 3 μm. When the thickness of the second contact layer 21b is within the above range, it helps to ensure high contact performance between it and the solar cell semi-finished product 1, and reduces the carrier transport barrier. For example, the thickness of the second contact layer 21b is 0.5 μm, 1 μm, 2 μm, 2.5 μm, or 3 μm, etc.

[0066] Furthermore, the thickness of the second diffusion suppression layer 22b is 0.5 μm to 1.5 μm. When the thickness of the second diffusion layer is within the above range, it can effectively ensure its blocking effect on the first metal in the second conductive layer 23b, and also ensure the contact effect between the second diffusion suppression layer 22b, the second conductive layer 23b, and the second contact layer 21b. For example, the thickness of the second diffusion suppression layer 22b is 0.5 μm, 0.7 μm, 0.9 μm, 1.1 μm, or 1.5 μm, etc.

[0067] Furthermore, the thickness of the second conductive layer 23b is 2 μm to 5 μm. When the thickness of the second conductive layer 23b is within the above range, it helps to ensure the conductivity of the second conductive structure to a higher degree, thereby further contributing to improving the photoelectric conversion efficiency of the solar cell. For example, the thickness of the second conductive layer 23b is 2 μm, 3 μm, 3.5 μm, 4 μm, or 5 μm, etc.

[0068] When the thicknesses of the second diffusion suppression layer 22b, the second conductive layer 23b, and the second contact layer 21b are all within the above-mentioned range, these three layers have a high degree of matching, which is more conducive to improving the performance of the second electrode structure 2b.

[0069] Further, see the return Figure 1 The electrode structure 2 also includes a protective layer 24, which is disposed on the surface of the conductive layer 23 facing away from the diffusion suppression layer 22. The protective layer 24 has higher oxidation resistance than the conductive layer 23. The protective layer 24, with its superior oxidation resistance, prevents the conductive layer 23 from oxidizing during high-temperature processes, thus contributing to a significant improvement in the stability of the electrode structure 2. Particularly during the module welding stage, the protective layer 24 further helps ensure the stability of the electrode structure 2 during welding, thereby contributing to the performance of the photovoltaic module.

[0070] Additionally, for protective layer 24, see the reference section. Figure 2 , Figure 3 and Figure 5 The protective layer 24 may be disposed only on the outer surface of the conductive layer 23; see back Figure 6 The protective layer 24 can also be disposed on the outer surface of the conductive layer 23 and on part of the surface of the diffusion suppression layer 22; see back Figure 7The protective layer 24 can also be disposed on the surface of the conductive layer 23, the partial diffusion suppression layer 22, and the partial contact layer 21. This application does not limit the specific arrangement of the protective layer 24, as long as it achieves the desired effect.

[0071] The protective layer 24 is made of at least one of tungsten, rhenium, tantalum, molybdenum, titanium, and hafnium. When the above-mentioned materials are used as the protective layer 24, they have high melting points and stability, which helps to prevent the first metal from oxidizing during high-temperature processes and improves the stability of the electrode structure 2.

[0072] Further, see the return Figure 1 The protective layer 24 includes a first protective layer 24a disposed on the light-receiving surface 11a of the solar cell semi-finished product 1 and a second protective layer 24b disposed on the backlighting surface 11b of the solar cell semi-finished product 1. The thickness of the first protective layer 24a is 1 μm to 2.5 μm, and the thickness of the second protective layer 24b is 0.5 μm to 1.5 μm. By controlling the thicknesses of the first protective layer 24a and the second protective layer 24b within the aforementioned ranges, the protective effect of the protective layer 24 is further improved, thereby enhancing the structural stability of the electrode structure 2 to a greater extent. For example, the thickness of the first protective layer 24a is 1 μm, 1.4 μm, 1.8 μm, 2.2 μm, or 2.5 μm, etc.; and the thickness of the second protective layer 24b is 0.5 μm, 0.7 μm, 0.9 μm, 1.2 μm, or 1.5 μm, etc.

[0073] Furthermore, the solar cell includes a back-contact solar cell, a PERC solar cell, or a passivated contact solar cell.

[0074] When the solar cell is a passivated contact solar cell, refer to the previous section. Figure 1 Electrode structure 2 includes a first electrode structure 2a and a second electrode structure 2b. Solar cell semi-finished product 1 includes: The silicon substrate 11 includes a light-receiving surface 11a and a back-lighting surface 11b disposed opposite to each other. A diffusion doped layer 12, a first functional layer 13, and a first electrode structure 2a are sequentially disposed on the light-receiving surface 11a of the silicon substrate 11. A passivation contact structure 14, a second functional layer 15, and a second electrode structure 2b are sequentially disposed on the backlight surface 11b of the silicon substrate 11. The passivation contact structure 14 includes a dielectric layer 141 and a doped silicon layer 142 sequentially stacked on the backlight surface 11b. Wherein, the first functional layer 13 is the first passivation layer 131 and / or the first antireflection layer 132, the second functional layer 15 is the second passivation layer and / or the second antireflection layer, the first contact layer 21a in the first electrode structure 2a is in ohmic contact with the diffused doped layer 12, and the second contact layer 21b in the second electrode structure 2b is in ohmic contact with the doped silicon layer 142.

[0075] In this passivated contact solar cell, the main components of the diffusion doped layer 12 and the doped silicon layer 142 are silicon. Therefore, when the first contact layer 21a contacts the diffusion doped layer 12 and the second contact layer 21b contacts the doped silicon layer 142, in order to further prevent the first metal from being transported to the diffusion doped layer 12 and the doped silicon layer 142, this application further provides a diffusion suppression layer 22 between the contact layer 21 and the conductive layer 23. This diffusion suppression layer is more helpful in blocking the first metal in the conductive layer 23 from being transported to the diffusion doped layer 12 and the doped silicon layer 142, thereby avoiding the formation of deep level defects to a greater extent.

[0076] This application discloses a method for fabricating a solar cell, which includes the following steps: A contact layer is prepared on a semi-finished solar cell, the semi-finished solar cell being made of silicon. A diffusion inhibition layer is prepared on the surface of the contact layer. The diffusion inhibition layer is made of a first metal and a second metal. The electronegativity difference between the first metal and the second metal is greater than or equal to 0.2. The first metal includes at least one of copper and aluminum. The contact layer is made of a third metal. The conductivity of the third metal is greater than that of the first metal. The solid solubility of the third metal in silicon is less than that of the first metal. A conductive layer is prepared on the surface of the diffusion suppression layer, the conductive layer being made of a first metal, thereby obtaining the aforementioned solar cell.

[0077] Furthermore, the contact layer includes a first contact layer and a second contact layer, wherein the step of preparing the first contact layer includes: A paste containing a third metal is printed on the light-receiving surface of the semi-finished solar cell and then dried. The dried slurry containing the third metal was subjected to a first sintering. The slurry containing the third metal after sintering is injected with a laser for a second sintering to obtain the first contact layer.

[0078] This application employs a two-stage sintering process, with the second stage using laser sintering. This results in a highly dense crystal structure for the first electrode, which exhibits excellent contact performance with the solar cell semi-finished product, thereby helping to optimize carrier transport.

[0079] In addition, when the first contact layer is prepared using the above method, the wet weight of the slurry containing the third metal is 4 mg to 10 mg, which effectively reduces the consumption of the slurry and lowers the production cost.

[0080] In the preparation of the first contact layer, the temperature of the first sintering is 700℃~820℃; in the second sintering step, the laser parameters include: laser wavelength of 800 nm~1300 nm, laser spot size of 1μm~1.4μm, current density of 340 A / cm²~1800 A / cm², laser power of 40 W~60 W, laser power density of 35 kW / cm²~60 kW / cm², and scanning speed of 4 m / s~7 m / s.

[0081] By controlling the parameters of the first and second sintering within the above range, it is more helpful to ensure the sintering effect of the first electrode structure, resulting in higher crystal density of the prepared first electrode structure, which is more helpful to improve the contact performance between the first electrode structure and the solar cell semi-finished product.

[0082] Furthermore, the steps for the second contact layer include: A paste containing a third metal is printed on the back surface of the semi-finished solar cell and then dried. The dried slurry containing the third metal is sintered a third time to obtain the second contact layer.

[0083] The slurry for the light-receiving surface and the back-lighting surface of this application adopts different sintering methods. The light-receiving surface is the main area for light absorption and charge generation, and it is more susceptible to the influence of the external environment. Therefore, in order to ensure the stability and reliability of the long-term use of the solar cell, it is necessary to further improve the sintering effect of the first electrode structure. In this way, the sintering effect of the first electrode structure is further optimized by adopting a two-stage sintering method, thereby improving the tightness of the connection between the first electrode structure and the solar cell semi-finished product.

[0084] Furthermore, as for the backlight surface, it is a secondary area for light absorption and charge generation, and the external environment has a relatively small impact on it. Therefore, a single sintering process can achieve the sintering effect required for the second electrode structure.

[0085] In addition, when the first contact layer is prepared using the above method, the wet weight of the slurry containing the third metal is 3 mg to 8.5 mg, which effectively reduces the consumption of the slurry and lowers the production cost.

[0086] The drying temperature is 100℃~200℃; the third sintering temperature is 650℃~780℃. Controlling the preparation parameters within the above range helps to optimize the sintering effect of the second electrode structure.

[0087] Furthermore, after the step of preparing a conductive layer on the surface of the diffusion inhibition layer, the preparation method further includes: preparing a protective layer on the outside of the conductive layer, wherein the antioxidant properties of the protective layer are higher than those of the conductive layer.

[0088] In addition, the protective layer, conductive layer and diffusion inhibition layer of this application may be made using at least one of screen printing, electroplating and electroless plating processes.

[0089] This application discloses a photovoltaic module, which includes the solar cell described above, or the photovoltaic module further includes the solar cell prepared by the above-described preparation method.

[0090] The technical solution of this application will be further explained below with reference to more specific embodiments and experimental test results.

[0091] Example 1: This embodiment provides a method for fabricating a solar cell, wherein a schematic diagram of the electrode structure of the solar cell is shown below. Figure 2 : Preparation of semi-finished solar cells: To texturize the N-type silicon substrate, a 1% alkaline solution was first used for texturing, followed by cleaning the silicon substrate with hydrogen peroxide and alkali.

[0092] The texturized silicon substrate is placed in a boron diffusion furnace, where boron trichloride gas is diffused at 1000℃~1080℃ to form a diffusion layer on the light-receiving surface of the silicon substrate.

[0093] The back surface of the silicon substrate is polished using a chain-type HF device.

[0094] A dielectric layer with a thickness of 1 nm was prepared on the gate line region and non-gate line region of the backlight surface of a silicon substrate. The silicon substrate was placed in a PECVD device, and N2O with a flow rate of 12000 sccm was introduced. The power was 12000 W and the reaction time was 80 s. A 40 nm thick doped silicon layer was fabricated on the dielectric layer: A first functional layer is sequentially fabricated from the inside to the outside on the side of the diffusion layer away from the silicon substrate. The first functional layer includes an aluminum oxide layer with a thickness of 5 nm and a silicon nitride layer with a thickness of 10 nm. A second functional layer is fabricated on the conductive layer. The second functional layer includes a silicon nitride functional layer with a thickness of 10 nm.

[0095] A first electrode structure is fabricated on the first functional layer. The first electrode structure includes a main gate and a sub-gate that are interconnected. The sub-gate includes a first contact layer, a first diffusion suppression layer, a first conductive layer, and a first protective layer. The width of the first electrode structure is 10 μm. The main grid is printed on the first functional layer and dried at a temperature of 110°C. A first contact layer is fabricated on the first functional layer, wherein the third metal of the first contact layer is silver, and the thickness of the first contact layer is 2.5 μm. A paste containing a third metal is printed on the first functional layer and then dried. The dried slurry containing the third metal was subjected to a first sintering at a temperature of 750℃. A second sintering process was performed by injecting a laser into the slurry containing the third metal after sintering. The laser wavelength was 1000 nm, the laser spot size was 1.2 μm, the current density was 900 A / cm², the laser power was 50 W, the laser power density was 45 kW / cm², and the scanning speed was 5 m / s, thus obtaining the first contact layer.

[0096] A first diffusion inhibition layer is prepared on the first contact layer using an electroplating process. The material of the first diffusion inhibition layer includes an alloy formed of copper and manganese, with a copper mass percentage of 70% and a thickness of 1.0 μm. A first conductive layer is prepared on the first diffusion suppression layer using an electroplating process. The material of the first conductive layer is copper, and the thickness of the first conductive layer is 3 μm. A first protective layer is prepared on the first conductive layer using an electroplating process. The material of the first protective layer is tungsten and rhenium, and the thickness of the first protective layer is 1.5 μm.

[0097] A second electrode structure is fabricated on the second functional layer. This second electrode structure includes an interconnected main gate and a sub-gate. The sub-gate includes a second contact layer, a second diffusion suppression layer, a second conductive layer, and a second protective layer. The width of the second electrode structure is 20 μm. The main grid is printed on the second functional layer and dried at a temperature of 110°C. A second contact layer is fabricated on the second functional layer, wherein the third metal of the second contact layer is silver, and the thickness of the second contact layer is 1.5 μm. A paste containing a third metal is printed on the second functional layer and dried at a temperature of 150°C. The dried slurry containing the third metal was sintered a third time, with the first sintering temperature being 750℃, to obtain the second contact layer.

[0098] A second diffusion inhibition layer is prepared on the second contact layer by electroplating. The material of the second diffusion inhibition layer includes an alloy formed of copper and manganese, with a copper mass percentage of 70% and a thickness of 1.0 μm. A second conductive layer is prepared on the second diffusion suppression layer using an electroplating process. The material of the second conductive layer is copper, and the thickness of the second conductive layer is 3 μm. A second protective layer is prepared on the second conductive layer using an electroplating process. The material of the second protective layer is tungsten and rhenium, and the thickness of the second protective layer is 1.0 μm.

[0099] Example 2: The only difference between this embodiment and Embodiment 1 is that the mass percentage of the first metal in the diffusion inhibition layer is 45%.

[0100] Example 3: The only difference between this embodiment and Embodiment 1 is that the mass percentage of the first metal in the diffusion inhibition layer is 90%.

[0101] Example 4: The only difference between this embodiment and Embodiment 1 is that the mass percentage of the first metal in the diffusion inhibition layer is 30%.

[0102] Example 5: The only difference between this embodiment and Embodiment 1 is that, in the electrode structure, a mask is first placed on the electrode structure containing the diffusion suppression layer, and then a conductive layer is prepared so that there is a distance between the end of the prepared conductive layer and the surface of the solar cell semi-finished product. For the specific electrode structure, please refer to [link to specific embodiment]. Figure 6 .

[0103] Comparative Example 1: The difference between this comparative example and Example 1 is that the electrode structure of this comparative example is a copper-clad silver structure, that is, a copper conductive layer is covered with a silver protective layer.

[0104] Comparative Example 2: The difference between this comparative example and Example 1 is that the diffusion inhibition layer in this comparative example is made of only the second metal manganese.

[0105] Comparative Example 3: The only difference between this comparative example and Example 1 is that the electronegativity difference between the first metal and the second metal in the diffusion inhibition layer of this comparative example is equal to 0.1, and the second metal is iron.

[0106] Performance testing: The solar cells prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were subjected to the following related tests: This application describes the performance testing of a solar cell using the Wavelabs solar simulator, including open-circuit voltage, short-circuit current, and fill factor. The Wavelabs simulator is a device that simulates sunlight, and when combined with electronic loads, data acquisition, and computing equipment, it is used to test the electrical performance of photovoltaic devices (including solar cells), such as Eta, Voc, Jsc, and FF, which reflect the performance of the solar cell. Test conditions: AM1.5, 1000 W / m 2The test environment temperature was 25℃, and the effective battery area was 20.38 cm². 2 The experimental test results are as follows, where Voc represents the open-circuit voltage, Jsc represents the short-circuit current density, FF represents the fill factor, and Eta represents the photoelectric conversion efficiency.

[0107] Contact testing: A TLM tester (model: TLM-SCAN, manufacturer: Shanghai Shunmiao Optoelectronic Technology Co., Ltd.) was used to perform probe pressing tests on the solar cells of each embodiment and comparative example to obtain the contact resistivity of the solar cells. The experimental test results are shown in Table 1, which presents the performance test results of the solar cells.

[0108] Table 1 Performance test results of solar cells

[0109] Analysis of the data from Example 1 and Comparative Example 1 shows that the photoelectric conversion efficiency and contact resistance of the electrode structure in Example 1 are both superior to those in Comparative Example 1. This demonstrates that using silver, which has low solid solubility and high conductivity, as the material for the contact layer helps to prevent its reaction with silicon, avoids the generation of deep-level defects, and thus significantly improves the contact performance between the contact layer and the solar cell semi-finished product, thereby enhancing the photoelectric conversion efficiency of the solar cell.

[0110] Analysis of the data from Example 1 and Comparative Example 2 shows that the photoelectric conversion efficiency and contact resistance of the electrode structure in Example 1 are both superior to those in Comparative Example 2. This indicates that the use of a manganese and copper alloy for the diffusion inhibition layer not only improves the conductivity of the diffusion inhibition layer but also results in higher contact performance between the diffusion inhibition layer and the contact layer and conductive layer.

[0111] Analysis of the data from Example 1 and Comparative Example 3 shows that the photoelectric conversion efficiency and contact resistance of the electrode structure in Example 1 are both superior to those in Comparative Example 3. This demonstrates that by controlling the electronegativity difference between the first and second metals in the diffusion suppression layer to be greater than or equal to 0.2, the diffusion resistance of the first metal is increased, effectively preventing the first metal from diffusing into the solar cell semi-finished product and avoiding the formation of deep-level defects.

[0112] Analysis of the data from Examples 1 to 4 shows that the photoelectric conversion efficiency and contact resistance of the electrode structure in Examples 1 to 3 are superior to those in Example 1. This indicates that the content of the first metal in the diffusion suppression layer in Examples 1 to 3 is more suitable. This more suitable content not only helps to prevent the first metal from diffusing towards the solar cell semi-finished product, but also effectively optimizes the interface matching between the diffusion suppression layer and the conductive layer and contact layer, thereby further improving the photoelectric conversion efficiency of the solar cell.

[0113] Analysis of the data from Examples 1 and 5 shows that the photoelectric conversion efficiency and contact resistance of the electrode structure in Example 5 are better than those in Example 1. It is evident that a distance between the end of the conductive layer and the surface of the solar cell semi-finished product helps to prevent the first metal from diffusing into the solar cell semi-finished product, thereby suppressing the generation of deep-level defects to a greater extent.

[0114] The solar cells and their preparation methods, as well as photovoltaic modules, disclosed in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the solar cells and their preparation methods, as well as the solar cells and photovoltaic modules. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A solar cell, characterized in that, The solar cell includes a solar cell semi-finished product and an electrode structure disposed on the solar cell semi-finished product. The material of the solar cell semi-finished product includes silicon. The electrode structure includes: a contact layer, and a diffusion suppression layer and a conductive layer sequentially stacked on the contact layer. The conductive layer is made of a first metal, the diffusion suppression layer is made of an alloy formed by the first metal and the second metal, and the contact layer is made of a third metal. The difference in electronegativity between the first metal and the second metal is greater than or equal to 0.

2. The first metal includes at least one of copper and aluminum. The conductivity of the third metal is greater than that of the first metal, and the solid solubility of the third metal in silicon is less than that of the first metal.

2. The solar cell according to claim 1, characterized in that, In the diffusion suppression layer, the mass percentage of the first metal is 45% to 90%.

3. The solar cell according to claim 1, characterized in that, The first metal includes copper, and the second metal includes at least one of manganese, chromium, and vanadium; and / or, The third metal includes at least one of silver and gold; and / or, The contact layer also includes nickel, and the nickel content in the contact layer is 1% to 30% by mass.

4. The solar cell according to claim 1, characterized in that, There is a distance between the end of the conductive layer and the surface of the solar cell semi-finished product; Alternatively, the end of the conductive layer is attached to the solar cell semi-finished product.

5. The solar cell according to claim 4, characterized in that, The top surface and at least part of the side surface of the contact layer protrude from the surface of the solar cell semi-finished product; The diffusion suppression layer includes a first diffusion suppression sub-section and a second diffusion suppression sub-section that are interconnected. The first diffusion suppression sub-section covers the top surface of the contact layer, and the second diffusion suppression sub-section is disposed at least on a portion of the side surface of the contact layer.

6. The solar cell according to claim 5, characterized in that, The conductive layer includes a first conductive sub-part and a second conductive sub-part connected to each other, wherein the first conductive sub-part covers the top surface of the first diffusion suppression sub-part. The second diffusion suppression sub-part covers all sides of the contact layer, and the first conductive sub-part covers all sides of the second diffusion suppression sub-part.

7. The solar cell according to claim 1, characterized in that, The electrode structure includes a first electrode structure disposed on the light-receiving surface of the solar cell semi-finished product and a second electrode structure disposed on the back surface of the solar cell semi-finished product. The first electrode structure includes a first contact layer, a first diffusion suppression layer, and a first conductive layer. The second electrode structure includes a second contact layer, a second diffusion suppression layer, and a second conductive layer.

8. The solar cell according to claim 7, characterized in that, The width of the first electrode structure is 5 μm to 22 μm; and / or, The thickness of the first electrode structure is 4 μm to 13 μm; and / or, The thickness of the first contact layer is 0.5 μm to 4 μm; and / or, The thickness of the first diffusion suppression layer is 0.5 μm to 1.5 μm; and / or, The thickness of the first conductive layer is 2μm~5μm; and / or, The width of the second electrode structure is 10μm~32μm; And / or, The thickness of the second electrode structure is 4 μm to 11 μm; And / or, The thickness of the second contact layer is 0.5 μm to 3 μm; and / or, The thickness of the second diffusion inhibition layer is 0.5 μm to 1.5 μm; and / or, The thickness of the second conductive layer is 2μm~5μm.

9. The solar cell according to any one of claims 1 to 8, characterized in that, The electrode structure further includes a protective layer disposed on the side surface of the conductive layer opposite to the diffusion inhibition layer, and the protective layer has higher oxidation resistance than the conductive layer.

10. The solar cell according to claim 9, characterized in that, The protective layer is made of at least one of tungsten, rhenium, tantalum, molybdenum, titanium, and hafnium; and / or, The protective layer includes a first protective layer disposed on the light-receiving surface of the solar cell semi-finished product and a second protective layer disposed on the back surface of the solar cell semi-finished product, wherein the thickness of the first protective layer is 1μm~2.5μm and the thickness of the second protective layer is 0.5μm~1.5μm.

11. The solar cell according to claim 1, characterized in that, The solar cell is a passivated contact solar cell, the electrode structure includes a first electrode structure and a second electrode structure, and the solar cell semi-finished product includes: A silicon substrate, the silicon substrate comprising a light-receiving surface and a back-lighting surface disposed opposite to each other; A diffusion doped layer, a first functional layer, and a first electrode structure are sequentially disposed on the light-receiving surface of the silicon substrate; A passivation contact structure, a second functional layer, and a second electrode structure are sequentially disposed on the backlight surface of the silicon substrate. The passivation contact structure includes a dielectric layer and a doped silicon layer sequentially stacked on the backlight surface. Wherein, the first functional layer is a first passivation layer and / or a first antireflection layer, the second functional layer is a second passivation layer and / or a second antireflection layer, the first contact layer in the first electrode structure is in ohmic contact with the diffused doped layer, and the second contact layer in the second electrode structure is in ohmic contact with the doped silicon layer.

12. A method for preparing a solar cell, characterized in that, The preparation method includes the following steps: A contact layer is prepared on a semi-finished solar cell, wherein the semi-finished solar cell is made of silicon. A diffusion inhibition layer is prepared on the surface of the contact layer, wherein the material of the diffusion inhibition layer includes a first metal and a second metal, the electronegativity difference between the first metal and the second metal is greater than or equal to 0.2, the first metal includes at least one of copper and aluminum, the material of the contact layer includes a third metal, the conductivity of the third metal is greater than that of the first metal, and the solid solubility of the third metal in silicon is less than that of the first metal. A conductive layer is prepared on the surface of the diffusion suppression layer, the material of the conductive layer comprising the first metal, to obtain the solar cell according to any one of claims 1 to 11.

13. The preparation method according to claim 12, characterized in that, The contact layer includes a first contact layer and a second contact layer, wherein the step of preparing the first contact layer includes: A paste containing the third metal is printed on the light-receiving surface of the solar cell semi-finished product and then dried. The dried slurry containing the third metal is subjected to a first sintering. The slurry containing the third metal after sintering is injected with a laser for a second sintering to obtain the first contact layer.

14. The preparation method according to claim 13, characterized in that, When preparing the first contact layer, the temperature of the first sintering is 700℃~820℃; and / or, In the second sintering step, the laser parameters include: laser wavelength of 800 nm to 1300 nm, laser spot size of 1 μm to 1.4 μm, current density of 340 A / cm² to 1800 A / cm², laser power of 40 W to 60 W, laser power density of 35 kW / cm² to 60 kW / cm², and scanning speed of 4 m / s to 7 m / s.

15. The preparation method according to claim 13, characterized in that, The steps for preparing the second contact layer include: A paste containing the third metal is printed on the back surface of the solar cell semi-finished product and then dried. The dried slurry containing the third metal is subjected to a third sintering to obtain the second contact layer.

16. The preparation method according to claim 15, characterized in that, The drying temperature is 100℃~200℃; and / or, The temperature for the third sintering is 650℃~780℃.

17. The preparation method according to any one of claims 12 to 16, characterized in that, After the step of preparing a conductive layer on the surface of the diffusion inhibition layer, the preparation method further includes: preparing a protective layer on the outside of the conductive layer, wherein the antioxidant properties of the protective layer are higher than those of the conductive layer.

18. A photovoltaic module, characterized in that, The photovoltaic module includes the solar cell according to any one of claims 1 to 11, or the photovoltaic module further includes the solar cell prepared by the preparation method according to any one of claims 12 to 17.

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