Solar cell, manufacturing method thereof and photovoltaic module

Abstract

The invention provides a solar cell, a manufacturing method thereof and a photovoltaic module, and relates to the field of photovoltaic technology. A transparent conductive layer is formed on at least one surface of a solar cell intermediate, an electrode is formed on the at least one transparent conductive layer, a target substance and the electrode are subjected to a chemical reaction, and a passivation layer is formed on the surface of the electrode. The use of an expensive protective layer metal plating solution is reduced, and the efficiency and reliability of the solar cell are improved while the cost is reduced.

Description

Technical Field

[0001] The present application 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] Metallization is one of the important links in the production of solar cells. Metallization refers to the preparation of metallized electrodes on the surface (front and / or surface) of the cell through contact or non-contact technology, so that the electrode and the cell form a close and efficient ohmic contact, and the photogenerated carriers are guided out of the cell. Metallization affects the cost and conversion efficiency of solar cells.

[0003] Copper electroplating technology is a non-contact metallization technology. Compared with screen printing technology, copper electroplating technology replaces silver with copper, which reduces costs, and can achieve double-sided metallization at the same time, improving production efficiency. However, metallic copper is easily oxidized in the air, affecting battery performance and subsequent string welding processes. If other metal protective layers, such as silver or tin, are covered on the outside of the copper electrode, the cost and process will increase. In addition, copper and silver can produce a primary battery with copper as the negative electrode. Once the silver protective layer is damaged and the copper is exposed, the corrosion of the copper will be greatly accelerated, affecting the efficiency and reliability of the solar cell. Summary of the invention

[0004] In order to alleviate, mitigate or eliminate the above-mentioned technical problems, the present application provides a solar cell and a manufacturing method thereof, and a photovoltaic module, which reduce costs while improving the efficiency and reliability of solar cells.

[0005] In a first aspect, the present application provides a method for manufacturing a solar cell, comprising:

[0006] providing a solar cell intermediate body having two surfaces opposite to each other in a thickness direction;

[0007] forming a transparent conductive layer on at least one surface of the solar cell intermediate;

[0008] forming an electrode on at least one of the transparent conductive layers;

[0009] A target substance is used to chemically react with the electrode to form a passivation layer on the surface of the electrode.

[0010] In a possible implementation, the step of using the target substance to chemically react with the electrode to form a passivation layer on the surface of the electrode includes:

[0011] The solar cell intermediate is placed in a passivation solution containing the target substance, and the temperature of the passivation solution is maintained at a preset temperature, so that the electrode and the target substance undergo a chemical reaction to form a passivation layer on the surface of the electrode, wherein the preset temperature is 70-100°C.

[0012] In a possible implementation manner, forming an electrode on at least one of the transparent conductive layers includes:

[0013] forming a first metal layer on at least one of the transparent conductive layers using a first plating solution, wherein the first plating solution includes a first brightener;

[0014] A second metal layer is formed on the first metal layer using a second plating solution, wherein the second plating solution includes a second brightener, and a concentration of the second brightener in the second plating solution is greater than a concentration of the first brightener in the first plating solution.

[0015] In a possible implementation, the concentration of the second brightener in the second plating solution is 1-5 mg / L greater than the concentration of the first brightener in the first plating solution.

[0016] In a possible implementation, the current density when forming the first metal layer is a first current density, and the current density when forming the second metal layer is a second current density. The first current density is 3-10ASD, and the second current density is 15-30ASD.

[0017] In a possible implementation, pulsed ultrasound is applied during the formation of the first metal layer, the pulse interval of the pulsed ultrasound is 5-10s, and the power of the pulsed ultrasound is 30-50W.

[0018] In a possible implementation, the forming of the first metal layer on at least one of the transparent conductive layers using the first plating solution includes:

[0019] forming a metal seed layer on at least one of the transparent conductive layers;

[0020] forming an inorganic mask layer on the metal seed layer;

[0021] Removing the inorganic mask layer in the grid line region of the solar cell intermediate;

[0022] A first metal layer is formed in the grid line region of the solar cell intermediate body using a first plating solution.

[0023] In a possible implementation manner, after forming a metal seed layer on at least one of the transparent conductive layers, the method further includes:

[0024] The solar cell intermediate is annealed in a process chamber at a temperature of 100-300°C.

[0025] In a possible implementation manner, the inorganic mask layer is formed in the process chamber.

[0026] In a possible implementation, the thickness of the metal seed layer is 80-200 nm; or

[0027] The thickness of the first metal layer is 10-15 μm; or

[0028] The thickness of the second metal layer is 0.5-2.0 μm.

[0029] In a possible implementation, the metal in the metal seed layer, the first metal layer and the second metal layer is copper, and the target substance is a salt derivative of a low-level organic acid.

[0030] In a possible implementation, the first brightener includes at least one of sodium polydisulfide propane sulfonate, sodium phenyl disulfide propane sulfonate, sodium alcoholthio propane sulfonate and sodium polydimethylamide sulfonate;

[0031] The second brightener includes at least one of sodium polydisulfide propane sulfonate, sodium phenyl disulfide propane sulfonate, sodium alcoholthio propane sulfonate and sodium polydimethylamide sulfonate.

[0032] In a second aspect, the present application provides a solar cell, comprising:

[0033] A silicon substrate having two surfaces in a thickness direction;

[0034] A transparent conductive layer, located on at least one surface of the silicon substrate;

[0035] An electrode is located on at least one of the transparent conductive layers, wherein a surface of the electrode has a passivation layer, and the passivation layer comprises a chemical compound made of the metal in the electrode and a target substance.

[0036] In a possible implementation, the electrode includes a first metal layer and a second metal layer in sequence from the inside to the outside, and a grain size of the second metal layer is smaller than a grain size of the first metal layer.

[0037] In a possible implementation, the metal in the first metal layer and the second metal layer is copper, and the first metal layer is a copper layer with (111) and (200) crystal planes preferentially oriented.

[0038] In a third aspect, the present application provides a photovoltaic assembly, comprising a plurality of solar cell strings, wherein the solar cell strings are composed of the solar cells described in the second aspect.

[0039] Compared with the prior art, this application has the following advantages:

[0040] The present application forms a transparent conductive layer on at least one surface of a solar cell intermediate, forms an electrode on at least one transparent conductive layer, and uses a target substance to chemically react with the electrode to form a passivation layer on the surface of the electrode. The present application passivates the electrode surface by a chemical passivation method, thereby reducing the use of expensive protective layer metal plating solution, reducing costs while improving the efficiency and reliability of solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0042] Figure 1 It is a schematic flow chart of a method for manufacturing a solar cell provided in an embodiment of the present application;

[0043] Figures 2 to 8 It is a schematic cross-sectional view of a solar cell in different steps of a method for manufacturing a solar cell provided in an embodiment of the present application.

[0044] In the figure: 210, solar cell intermediate; 220, transparent conductive layer; 230, metal seed layer; 240, inorganic mask layer; 250, first metal layer; 260, second metal layer; 270, passivation layer; 201, gate line area; 202, non-gate line area. DETAILED DESCRIPTION

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0046] As shown in this application, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0047] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0048] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0049] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0050] In addition, it should be noted that the use of words such as "first" and "second" to limit objects is only for the convenience of distinguishing the corresponding objects. If not otherwise stated, the above words have no special meanings and therefore cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from commonly known and commonly used terms, some of the terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0051] It should be understood that when a component is referred to as being “on” or “contacting” another component, it can be directly on or contacting the other component, or intervening components may be present. In contrast, when a component is referred to as being “directly on” or “directly contacting” another component, there are no intervening components.

[0052] Flowcharts are used in the present application to illustrate the operations performed by the methods according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0053] Figure 1 FIG. 1 is a flow chart of a method for manufacturing a solar cell provided in an embodiment of the present application. Figure 1 As shown, the method for manufacturing a solar cell comprises the following steps:

[0054] Step S110: providing a solar cell intermediate.

[0055] Step S120 : forming a transparent conductive layer on at least one surface of the solar cell intermediate.

[0056] Step S130: forming an electrode on at least one transparent conductive layer.

[0057] Step S140: using the target substance to chemically react with the electrode to form a passivation layer on the surface of the electrode.

[0058] Next, combine the reference Figure 2-Figure 8 Steps S110 to S140 are described in detail.

[0059] In step S110, a solar cell intermediate 210 is provided. The solar cell intermediate 210 has two surfaces opposite to each other in the thickness direction thereof, which are the front and back surfaces of the solar cell, respectively. When the solar cell is working, the front surface faces the sun. A plurality of solar cells can form a solar cell string, and a plurality of solar cell strings can further form a photovoltaic module.

[0060] A specific layer is formed on the surface of the silicon substrate to obtain a solar cell intermediate 210. The silicon substrate can be N-type doped single crystal silicon or P-type doped single crystal silicon. An amorphous silicon layer can be formed on the surface of the silicon substrate, or a tunneling layer and a doped polycrystalline silicon layer can be formed on the surface of the silicon substrate to obtain a solar cell intermediate 210.

[0061] In step S120, a transparent conductive layer 220 is formed on at least one surface of the solar cell intermediate 210. It should be noted that the transparent conductive layer 220 can be formed on the front side of the solar cell intermediate 210 alone, or on the back side of the solar cell intermediate 210 alone, or on both the front side and the back side of the solar cell intermediate 210 at the same time. The method for manufacturing the solar cell of the present application is described below by taking the method of forming the transparent conductive layer 220 on both the front side and the back side of the solar cell intermediate 210 at the same time as an example, as shown in FIG. Figure 2 shown.

[0062] The transparent conductive layer 220 may be a transparent conductive oxide (TCO) film, such as a tin-doped indium oxide (ITO) film or a tungsten-doped indium oxide (IWO) film.

[0063] In step S130, an electrode is formed on at least one transparent conductive layer 220. It should be noted that the electrode may be formed on the transparent conductive layer 220 on the front or back alone, or may be formed on both the transparent conductive layer 220 on the front and back. The method for manufacturing a solar cell of the present application is described below by taking the formation of electrodes on the transparent conductive layer 220 on the front and back as an example.

[0064] In some embodiments, please refer to Figure 3-Figure 6 , step S130 includes the following steps:

[0065] Step S131 : forming a first metal layer 250 on the transparent conductive layer 220 using a first plating solution, wherein the first plating solution includes a first brightener.

[0066] The thickness of the first metal layer 250 is about 10-15 μm, such as 10 μm, 11 μm, 12 μm, 13 μm, 14 μm or 15 μm. The metal in the first metal layer 250 can be copper, silver or other metals, and the following text takes the first metal layer 250 as a copper layer as an example for explanation. For example, the first metal layer 250 can be prepared by copper electroplating technology, the current density when forming the first metal layer is the first current density, and the plating time is 6-20 min, such as 6 min, 8 min, 10 min, 12 min, 16 min, 18 min or 20 min. The first current density is about 3-10 ASD, such as 3 ASD, 5 ASD, 7 ASD or 10 ASD.

[0067] In some embodiments, pulsed ultrasound is applied during the formation of the first metal layer 250, the pulse interval of the pulsed ultrasound is 5-10s, and the power of the pulsed ultrasound is 30-50W. For example, 40kHz ultrasound is applied during the copper electroplating process, the power of the ultrasound is 40W, the ultrasound is in pulse form, runs for 10s, pauses for 10s, and repeats this process until the first metal layer 250 is completed. In this embodiment, a copper layer with (111) and (200) crystal planes preferentially oriented can be obtained. The use of ultrasound-assisted electroplating can improve the degree of preferential orientation of the (111) and (200) crystal planes and improve the electrical properties of the first metal layer 250.

[0068] The first plating solution includes a first copper salt, a first acid solution, a first chloride, a first brightener, a first leveler and a first inhibitor. The first copper salt includes at least one of copper sulfate, copper nitrate and copper sulfonate; the first acid solution includes at least one of sulfuric acid, formic acid, acetic acid and nitric acid; the first chloride includes at least one of sodium chloride, hydrogen chloride and potassium chloride; the first brightener includes at least one of polydisulfide propane sodium sulfonate, phenyl disulfide propane sodium sulfonate, alcohol thiopropane sodium sulfonate and polydimethylamide sodium sulfonate; the first leveler includes at least one of polyethylene imine alkyl salt, methyl violet, saffron, thiazine dyes, triphenylmethane dyes, polymerized thio dyes, phenazine dyes, Jianna Green B, Jianna Black R and cross-linked polyamide; the first inhibitor includes at least one of polyethylene glycol, polyamine and ethylene oxide adducts, fatty amine and ethylene oxide adducts, fatty amine polyoxyethylene ether and octylphenol polyoxyethylene ether. Based on the total amount of the first plating solution, the concentration of copper salt is 60g / L-200g / L, the concentration of acid solution is 25g / L-150g / L, the concentration of chloride ions in chloride is 20mg / L-100mg / L, the concentration of brightener is 1mg / L-20mg / L, the concentration of leveler is 10mg / L-100mg / L, and the concentration of inhibitor is 50mg / L-1000mg / L. For example, the first plating solution includes copper sulfate, sulfuric acid, sodium chloride, poly(disulfide-bis-propane sulfonate), polyethylene imine alkyl salt and polyethylene glycol. Based on the total amount of the first plating solution, the concentration of copper sulfate is 60g / L-200g / L, the concentration of sulfuric acid is 25g / L-150g / L, the concentration of chloride ions in sodium chloride is 20mg / L-100mg / L, the concentration of poly(disulfide-bis-propane sulfonate) is 1mg / L-20mg / L, the concentration of polyethylene imine alkyl salt is 10mg / L-100mg / L, and the concentration of polyethylene glycol is 50mg / L-1000mg / L.

[0069] In some embodiments, step S131 includes: forming a metal seed layer on at least one transparent conductive layer; forming an inorganic mask layer on the metal seed layer; removing the inorganic mask layer in the grid line region of the solar cell intermediate body, and forming a first metal layer in the grid line region of the solar cell intermediate body using a first plating solution. Figure 3 A metal seed layer 230 with a thickness of about 80-200 nm is formed on the transparent conductive layer 220. The metal in the metal seed layer 230 may be copper, silver or other metals. The metal seed layer 230 is a copper seed layer as an example for description. For example, the copper seed layer may be prepared by magnetron sputtering physical vapor deposition (PVD) at a deposition rate of 0.2-1.0 nm / s and a temperature of 150-300° C.

[0070] In some embodiments, after the copper seed layer is deposited, the solar cell intermediate is annealed in the process chamber, such as in the chamber of the PVD equipment, the annealing temperature is 100-300°C, such as 100°C, 200°C or 300°C, and the annealing time is 10-30min, such as 10min, 20min or 30min. Low temperature annealing can reduce the formation of twins, reduce the density of crystal defects, generate larger grains, improve the degree of preferred orientation of the crystal plane of subsequent electroplated copper, and improve the adhesion and electrical properties of the copper seed layer.

[0071] Combined with reference Figure 4 , an inorganic mask layer 240 is formed on the metal seed layer 230. The inorganic mask layer 240 can be a thin film such as SiNx, with a thickness of about 10-30nm, such as 10nm, 20nm or 30nm. For example, the inorganic mask layer 240 can be formed by the following method: depositing the inorganic mask layer 240 in the process chamber of the annealing treatment, with a deposition rate of 0.2-1.0nm / s, effectively avoiding the copper seed layer from contacting the air, and preventing the copper seed layer from oxidizing in the air.

[0072] Combined with reference Figure 5 , the inorganic mask layer 240 in the grid line region 201 of the solar cell intermediate body is removed, and the inorganic mask layer 240 in the non-grid line region 202 is retained. For example, a laser device can be used to pattern the inorganic mask layer 240 to expose the copper seed layer 230 in the grid line region 201. In actual operation, an ultraviolet picosecond laser can be used to locally ablate the inorganic mask layer 240 according to the designed electrode pattern to remove the inorganic mask layer 240 in the grid line region 201 and retain the inorganic mask layer 240 in the non-grid line region 202. The laser wavelength is 355nm, the frequency is 50KHz, and the irradiation power is 0.5-1.2j / cm 2 , such as 0.5j / cm 2 , 0.8j / cm 2 , 1.0j / cm 2 or 1.2j / cm 2 .

[0073] Combined with reference Figure 6 A first metal layer 250 is formed in the grid line region 201 of the solar cell intermediate body using a first plating solution.

[0074] Step S132: using a second plating solution to form a second metal layer 260 on the first metal layer 250, the second plating solution comprising a second brightener, and the concentration of the second brightener in the second plating solution is greater than the concentration of the first brightener in the first plating solution. In some embodiments, the concentration of the second brightener in the second plating solution is 1-5 mg / L greater than the concentration of the first brightener in the first plating solution, such as 1 mg / L, 2 mg / L, 3 mg / L, 4 mg / L or 5 mg / L greater.

[0075] The thickness of the second metal layer 260 is about 0.5-2.0 μm, such as 0.5 μm, 0.7 μm, 1.0 μm, 1.5 μm or 2.0 μm. The metal in the second metal layer 260 can be copper, silver or other metals. The following text takes the second metal layer 260 as a copper layer as an example for explanation. For example, the second metal layer 260 can be prepared by copper electroplating technology, and the current density when forming the second metal layer is the second current density, and the plating time is 5-20s, such as 5s, 8s, 10s, 15s, 18s or 20s. The second current density is greater than the first current density. Increasing the current density is conducive to grain refinement, so that the grain size of the second metal layer 260 is smaller than the grain size of the first metal layer 250, thereby improving the efficiency of the subsequent passivation reaction. For example, the second current density is about 15-30 ASD, such as 15 ASD, 20 ASD, 25 ASD or 30 ASD. If the current density is too low, the effect is not obvious. If it is too high, the protective layer is prone to "burning".

[0076] The second plating solution includes a second copper salt, a second acid solution, a second chloride, a second brightener, a second leveler, and a second inhibitor. The second copper salt includes at least one of copper sulfate, copper nitrate, and copper sulfonate; the second acid solution includes at least one of sulfuric acid, formic acid, acetic acid, and nitric acid; the second chloride includes at least one of sodium chloride, hydrogen chloride, and potassium chloride; the second brightener includes at least one of polydisulfide propane sodium sulfonate, phenyl disulfide propane sodium sulfonate, alcohol thiopropane sodium sulfonate, and polydimethylamide sodium sulfonate; the second leveler includes at least one of polyethylene imine alkyl salt, methyl violet, saffron, thiazine dyes, triphenylmethane dyes, polymerized thio dyes, phenazine dyes, Jianna Green B, Jianna Black R, and cross-linked polyamide; the second inhibitor includes at least one of polyethylene glycol, polyamine and ethylene oxide adducts, fatty amine and ethylene oxide adducts, fatty amine polyoxyethylene ethers, and octylphenol polyoxyethylene ethers. For example, 1-5 mg / L of sodium poly(disulfide-bispropanesulfonate) may be additionally added to the first plating solution.

[0077] Combined with reference Figure 7 In step S140, the target substance is used to chemically react with the electrode to form a passivation layer 270 on the surface of the electrode, that is, the passivation layer 270 includes a chemical compound made of the metal in the electrode and the target substance. In actual operation, the solar cell intermediate can be placed in a passivation solution containing the target substance, and the temperature of the passivation solution is maintained at a preset temperature, so that the electrode and the target substance react chemically to form a passivation layer 270 on the surface of the electrode, wherein the preset temperature is 70-100°C, which effectively controls the passivation reaction.

[0078] In some embodiments, the target substance is a salt derivative of a low-level organic acid, and the salt derivative of the low-level organic acid can react chemically with copper to generate a chemical compound, thereby forming a passivation layer 270 on the surface of the second metal layer 260. For example, a mixed solution of formate and dimethylformamide is used to perform a heat bath treatment on the solar cell intermediate, and the formate reacts with the copper atoms of the second metal layer 260 to generate [Cu(μ-HCOO)(OH)2]2, which provides maximum corrosion protection without affecting the electrical properties of the electrode. In actual operation, the solar cell intermediate treated in step S130 can be washed and dried, placed in a passivation solution, soaked for 4 minutes, taken out and dried, wherein the temperature of the passivation solution is maintained at 80°C.

[0079] After step S140, the inorganic mask layer 240 and the copper seed layer 230 in the non-gridline region 202 are removed, and the resulting solar cell is as follows: Figure 8 In actual operation, a mixture of dilute acid and hydrogen peroxide can be used to remove the copper seed layer 230, and a stripping solution can be used to remove the inorganic mask layer 240. For example, the stripping solution includes: sulfuric acid 10 wt%; HF 10 wt%; H2O2 10 wt%; DI water 70 wt%, the stripping temperature is 30°C, and the time is 30-50s.

[0080] Please refer to Figure 8 , Figure 1 The solar cell manufactured by the manufacturing method shown comprises a silicon substrate, a transparent conductive layer 220 and an electrode. The silicon substrate has two surfaces in the thickness direction, the transparent conductive layer 220 is located on at least one surface of the silicon substrate, the electrode is located on at least one transparent conductive layer 220, and the surface of the electrode has a passivation layer 270.

[0081] In some embodiments, the electrode includes a first metal layer 250 and a second metal layer 260 from the inside to the outside, and a metal seed layer 230 may be formed between the first metal layer 250 and the transparent conductive layer 220. In some embodiments, the grain size of the second metal layer 260 is smaller than the grain size of the first metal layer 250, which is conducive to the penetration and reaction of the passivating agent and effectively improves the reliability of the battery. In some embodiments, the metals in the first metal layer 250 and the second metal layer 260 are both copper, which reduces the preparation cost of the electrode. The first metal layer 250 is a copper layer with preferential orientation of (111) and (200) crystal planes, which improves the conductivity of the electrode, thereby improving the conversion efficiency of the battery.

[0082] The basic concepts have been described above. Obviously, for those skilled in the art, the above disclosure is only an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0083] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0084] Similarly, it should be noted that in order to simplify the description disclosed in this application and thus help understand one or more embodiments, in the above description of the embodiments of this application, multiple features are sometimes merged into one embodiment, figure or description thereof. However, this disclosure method does not mean that the subject of this application requires more features than the features mentioned. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0085] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining the digits. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0086] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the present application.

Claims

1. A method for manufacturing a solar cell, characterized in that: include: providing a solar cell intermediate body having two surfaces opposite to each other in a thickness direction; forming a transparent conductive layer on at least one surface of the solar cell intermediate; forming an electrode on at least one of the transparent conductive layers; A target substance is used to chemically react with the electrode to form a passivation layer on the surface of the electrode.

2. The method according to claim 1, characterized in that The step of using the target substance to chemically react with the electrode to form a passivation layer on the surface of the electrode comprises: The solar cell intermediate is placed in a passivation solution containing the target substance, and the temperature of the passivation solution is maintained at a preset temperature, so that the electrode and the target substance undergo a chemical reaction to form a passivation layer on the surface of the electrode, wherein the preset temperature is 70-100°C.

3. The method according to claim 1, characterized in that The step of forming an electrode on at least one of the transparent conductive layers comprises: forming a first metal layer on at least one of the transparent conductive layers using a first plating solution, wherein the first plating solution includes a first brightener; A second metal layer is formed on the first metal layer using a second plating solution, wherein the second plating solution includes a second brightener, and a concentration of the second brightener in the second plating solution is greater than a concentration of the first brightener in the first plating solution.

4. The method according to claim 3, characterized in that The concentration of the second brightener in the second plating solution is 1-5 mg / L greater than the concentration of the first brightener in the first plating solution.

5. The method according to claim 3, characterized in that The current density when forming the first metal layer is the first current density, and the current density when forming the second metal layer is the second current density. The first current density is 3-10 ASD, and the second current density is 15-30 ASD.

6. The method according to claim 3, characterized in that During the process of forming the first metal layer, pulsed ultrasonic waves are applied, wherein the pulse interval of the pulsed ultrasonic waves is 5-10s, and the power of the pulsed ultrasonic waves is 30-50W.

7. The method according to claim 3, characterized in that The forming of the first metal layer on at least one of the transparent conductive layers using the first plating solution comprises: forming a metal seed layer on at least one of the transparent conductive layers; forming an inorganic mask layer on the metal seed layer; Removing the inorganic mask layer in the grid line region of the solar cell intermediate; A first metal layer is formed in the grid line region of the solar cell intermediate body using a first plating solution.

8. The method according to claim 7, characterized in that After forming a metal seed layer on at least one of the transparent conductive layers, the method further comprises: The solar cell intermediate is annealed in a process chamber at a temperature of 100-300°C.

9. The method according to claim 8, characterized in that The inorganic mask layer is formed in the process chamber.

10. The method according to claim 7, characterized in that The thickness of the metal seed layer is 80-200 nm; or The thickness of the first metal layer is 10-15 μm; or The thickness of the second metal layer is 0.5-2.0 μm.

11. The method according to claim 7, characterized in that The metal in the metal seed layer, the first metal layer and the second metal layer is copper, and the target substance is a salt derivative of a low-level organic acid.

12. The method according to claim 3, characterized in that The first brightener comprises at least one of sodium polydisulfide propane sulfonate, sodium phenyl disulfide propane sulfonate, sodium alcoholthio propane sulfonate and sodium polydimethylamide sulfonate; The second brightener includes at least one of sodium polydisulfide propane sulfonate, sodium phenyl disulfide propane sulfonate, sodium alcoholthio propane sulfonate and sodium polydimethylamide sulfonate.

13. A solar cell, characterized in that: include: A silicon substrate having two surfaces in a thickness direction; A transparent conductive layer, located on at least one surface of the silicon substrate; An electrode is located on at least one of the transparent conductive layers, wherein a surface of the electrode has a passivation layer, and the passivation layer comprises a chemical compound made of the metal in the electrode and a target substance.

14. The solar cell according to claim 13, wherein: The electrode includes a first metal layer and a second metal layer in sequence from the inside to the outside, and the grain size of the second metal layer is smaller than the grain size of the first metal layer.

15. The solar cell according to claim 14, wherein: The metal in the first metal layer and the second metal layer is copper, and the first metal layer is a copper layer with (111) and (200) crystal planes preferentially oriented.

16. A photovoltaic module, characterized in that: The invention comprises a plurality of solar cell strings, wherein the solar cell strings are composed of the solar cells according to any one of claims 13 to 15.

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