Method for manufacturing solar cell

Abstract

The invention discloses a manufacturing method of a solar cell, which is characterized in that after a first metal layer and a second metal layer which are stacked are sequentially formed on a first surface, laser is used for scanning an isolation area, the second metal layer located in the isolation area is modified, and a middle substrate subjected to laser scanning treatment is cleaned by corrosive liquid. The modified second metal layer and the first metal layer below the modified second metal layer are removed through etching of the corrosive liquid, and the first metal layer and the second metal layer in the remaining electrode area form an electrode structure; the corrosion resistance of the second metal layer to the corrosive liquid is greater than that of the first metal layer to the corrosive liquid. Compared with an electrode structure formed through printing, the method does not need to repeatedly clean the screen printing plate, and the process is simplified; and compared with the electrode structure formed by electroplating, the equipment cost for forming the electrode structure is reduced.

Description

[0001] This application claims the priority of the Chinese patent filed with the China Patent Office on October 31, 2024, with application number 202411547605.2 and application name “Method for manufacturing solar cells”, all contents of which are incorporated by reference in this application. Technical Field

[0002] The present application relates to the field of photovoltaic technology, and in particular to a method for manufacturing a solar cell. Background Art

[0003] Solar cells are now being used more and more widely as a new energy alternative. Among them, photovoltaic solar cells are devices that convert sunlight into electrical energy. Specifically, solar cells use the photovoltaic principle to generate carriers, and then use electrodes to lead the carriers out, thereby facilitating the effective use of electrical energy.

[0004] However, in the existing solar cell manufacturing process, the electrode structure of the solar cell is generally manufactured by screen printing. The screen printing process will leave many discretely distributed conductive residues at the edge of each electrode structure. These conductive residues are not in contact with the electrode, so they not only have no carrier extraction function, but also block light and affect the collection of carriers. In addition, the electrodes are formed by screen printing or electroplating, and the main raw material of the electrodes is silver, resulting in a high cost of the electrode structure. In addition, the printing screen used in the screen printing process needs to be cleaned before it can be reused, and the process is complicated; the cost of electroplating equipment is high, resulting in a high cost of making electrodes. Summary of the invention

[0005] The purpose of the present application is to provide a method for manufacturing a solar cell, so as to reduce the manufacturing cost of an electrode structure and improve the utilization rate of light.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] A method for manufacturing a solar cell, comprising:

[0008] Providing an intermediate substrate, the intermediate substrate comprising a first surface and a second surface opposite to each other, the first surface comprising an electrode region and an isolation region;

[0009] sequentially forming a first metal layer and a second metal layer stacked on the first surface, wherein the first metal layer is closer to the intermediate substrate than the second metal layer;

[0010] Scanning the isolation area with a laser to modify the second metal layer located in the isolation area;

[0011] The intermediate substrate after laser scanning processing is cleaned with a corrosive liquid, and the corrosive liquid etches away the modified second metal layer and the first metal layer thereunder, and the first metal layer and the second metal layer in the remaining electrode area form an electrode structure; wherein the corrosion resistance of the second metal layer to the corrosive liquid is greater than that of the first metal layer to the corrosive liquid.

[0012] In the solar cell structure formed by the above-mentioned solar cell manufacturing method, since the first metal layer is covered by the second metal layer, the second metal layer plays a role in protecting the first metal layer and preventing the first metal layer from being oxidized and corroded, the corrosion resistance of the second metal layer before modification to the corrosive liquid is greater than that of the first metal layer to the corrosive liquid. In this way, the first metal layer can be formed by selecting a metal with low cost and not resistant to corrosion by the corrosive liquid, and the second metal layer can be formed by selecting a metal resistant to corrosion by the corrosive liquid. Compared with the prior art in which the electrode structure is an integrated structure and all metals resistant to corrosion by the corrosive liquid are selected, the selectivity of the first metal layer is increased, and the manufacturing cost of the electrode structure is reduced by selecting a metal with low cost to form the first metal layer.

[0013] In the manufacturing method of the solar cell described above, the second metal layer in the isolation area is first modified by laser scanning, and then the first metal layer and the second metal layer are patterned by etching with a corrosive liquid. The width of the electrode structure can be accurately controlled by controlling the diameter of the laser spot, so that the size of the electrode structure finally prepared is also more accurate. In this way, the first metal layer and the second metal layer in the isolation area can be completely removed. Compared with the electrode structure formed by printing in the prior art, more conductive residues can be prevented from remaining in the isolation area, which avoids more light blocking by conductive residues, improves light utilization, and improves carrier collection efficiency. In addition, compared with printing to form an electrode structure, there is no need to repeatedly clean the screen, which simplifies the process; compared with electroplating to form an electrode structure, the equipment cost of forming the electrode structure is reduced.

[0014] In one implementation, the second metal layer located in the isolation region is modified by scanning the isolation region with a laser, including:

[0015] Laser scanning is used to isolate the area so that a metal alloy is formed between the second metal layer located in the isolation area and the first metal layer therebelow; the corrosion resistance of the metal alloy to the corrosive liquid is lower than that of the second metal layer to the corrosive liquid; when the corrosive liquid is used to clean the intermediate substrate after the laser scanning process, the corrosive liquid will not corrode the area not irradiated by the laser, that is, the second metal layer in the electrode area and the first metal layer therebelow.

[0016] Alternatively, the second metal layer located in the isolation area is modified by scanning the isolation area with a laser, comprising:

[0017] The isolation area is scanned by laser so that the density of the second metal layer in the isolation area is less than that of the second metal layer in the electrode area. It can be understood that the lower the density, that is, the looser the second metal layer, the corrosive liquid can penetrate the first metal layer below through the loose second metal layer, contact and react with the first metal layer below it, and remove the first metal layer in the isolation area. Since the first metal layer in the isolation area irradiated by the laser is corroded, and the second metal layer above it is relatively loose, the second metal layer in the isolation area will be taken away during the corrosion process of the corrosive liquid, especially when the thickness of the second metal layer is relatively thin, or when the steps of purging, ultrasonic cleaning, etc. are added, the second metal layer in the isolation area is more easily removed, and the first metal layer and the second metal layer in the electrode area are retained to form an electrode structure.

[0018] Alternatively, the second metal layer located in the isolation area is modified by scanning the isolation area with a laser, comprising:

[0019] The isolation area is scanned by laser so that the second metal layer in the isolation area and the first metal layer thereunder form a metal alloy, and the density of the metal alloy is less than the density of the second metal layer in the electrode area; wherein the corrosion resistance of the metal alloy to the corrosive liquid is less than the corrosion resistance of the second metal layer to the corrosive liquid. In this way, the corrosive liquid can more quickly and completely remove the metal alloy with poor corrosion resistance and low density in the isolation area.

[0020] In one implementation, the roughness of the isolation region of the intermediate substrate is greater than the roughness of the electrode region of the intermediate substrate;

[0021] Before the second metal layer in the isolation region is modified, the density of the second metal layer in the isolation region is less than that of the second metal layer in the electrode region. In this way, it is more conducive for the corrosive liquid to penetrate the second metal layer in the isolation region and react with the first metal layer below it, thereby removing the first metal layer in the isolation region.

[0022] In one implementation, the power of the laser is 10W to 150W; and / or the frequency of the laser is 500KHz to 4000KHz; and / or the pulse width is 10ps to 20ps. Reasonable laser power, frequency, pulse width and other parameters enable the laser to modify the second metal layer in the isolation area, preventing insufficient laser intensity or other unreasonable parameters from affecting the modification of the second metal layer in the isolation area.

[0023] In one implementation, the isolation region of the intermediate substrate is a velvet structure, and the electrode region of the intermediate substrate is a polished surface structure. The first metal layer and the second metal layer corresponding to the isolation region will rise and fall along with the rise and fall of the velvet structure, that is, the first metal layer and the second metal layer formed in the isolation region also have substantially the same undulating morphology as the velvet structure. Therefore, when the isolation region is a velvet structure, the first metal layer and the second metal layer formed in the isolation region also have corresponding uneven features, which can reduce the formation quality of the first metal layer and the second metal layer in the isolation region, reduce the adhesion and compactness of the first metal layer and the second metal layer in the isolation region, and thus facilitate the rapid etching and removal of the first metal layer and the second metal layer in the isolation region by the corrosive liquid.

[0024] In one implementation, after providing an intermediate substrate and before sequentially forming a first metal layer and a second metal layer stacked on a first surface, the method for manufacturing a solar cell further includes:

[0025] A transparent conductive layer is formed on the first surface of the intermediate substrate. The transparent conductive layer has a high conductivity and can timely guide the collected carriers to reduce the carrier recombination rate.

[0026] The intermediate substrate after laser scanning is cleaned by using a corrosive liquid, and the modified second metal layer and the first metal layer thereunder are removed by etching with the corrosive liquid, and the first metal layer and the second metal layer in the remaining electrode area form an electrode structure; comprising:

[0027] The intermediate substrate is cleaned with an etching solution, and the etching solution removes the second metal layer in the isolation area and the first metal layer and the transparent conductive layer thereunder. The first metal layer and the second metal layer in the remaining electrode area form an electrode structure, and the transparent conductive layer in the remaining electrode area forms a transparent conductive pattern. In this step, the first metal layer, the second metal layer and the transparent conductive layer are patterned together, avoiding the patterning of the transparent conductive layer alone, simplifying the processing technology and improving the processing efficiency.

[0028] Alternatively, the method for manufacturing a solar cell further comprises:

[0029] forming a transparent conductive layer on the first surface of the intermediate substrate, and patterning the transparent conductive layer to form a transparent conductive pattern;

[0030] The method sequentially forms a first metal layer and a second metal layer stacked on a first surface, comprising: forming the first metal layer and the second metal layer on an intermediate substrate formed with a transparent conductive pattern. In the method, the width of the transparent conductive pattern can be greater than or less than the width of the first metal layer, and after the transparent conductive pattern is formed, the first metal layer and the second metal layer are removed by etching. When selecting an etching solution, it is not necessary to consider the corrosiveness of the etching solution to the transparent conductive layer, so that the range of etching solutions is wider.

[0031] In one implementation, the second metal layer located in the isolation area and the first metal layer and the transparent conductive layer thereunder are removed by etching with a corrosive liquid, and the transparent conductive layer in the remaining electrode area forms a transparent conductive pattern; wherein the width of the transparent conductive pattern is equal to the width of the first metal layer; thus, the bottom of the first metal layer is completely in contact with the transparent conductive pattern, thereby reducing the contact resistance of the bottom surface of the first metal layer and further improving the carrier extraction rate.

[0032] or,

[0033] A transparent conductive layer is formed on the first surface of the intermediate substrate, and the transparent conductive layer is processed to form a transparent conductive pattern; wherein the width of the transparent conductive pattern is greater than or equal to the width of the first metal layer.

[0034] In one implementation, after providing an intermediate substrate and before sequentially forming a first metal layer and a second metal layer stacked on a first surface, the method for manufacturing a solar cell further includes:

[0035] A buffer layer is formed on the first surface of the intermediate substrate, and the buffer layer facilitates the deposition of the first metal layer and improves the adhesion between the electrode structure and the intermediate substrate.

[0036] The intermediate substrate after laser scanning is cleaned by using a corrosive liquid, and the modified second metal layer and the first metal layer thereunder are removed by etching with the corrosive liquid, and the first metal layer and the second metal layer in the remaining electrode area form an electrode structure; comprising:

[0037] The intermediate substrate is cleaned with a corrosive liquid, and the corrosive liquid etches away the second metal layer located in the isolation area and the first metal layer and the buffer layer thereunder. The first metal layer and the second metal layer in the remaining electrode area form an electrode structure, and the buffer layer in the remaining electrode area forms a buffer pattern. In this step, the first metal layer, the second metal layer and the buffer layer are patterned together, thereby avoiding patterning of the buffer layer alone, simplifying the processing technology, and improving the processing efficiency.

[0038] Alternatively, the method for manufacturing a solar cell further comprises:

[0039] forming a buffer layer on the first surface of the intermediate substrate, and patterning the buffer layer to form a buffer pattern;

[0040] The method sequentially forms a first metal layer and a second metal layer stacked on a first surface, comprising: forming the first metal layer and the second metal layer on an intermediate substrate after a buffer layer patterning process is formed. In the method, the width of the buffer pattern can be greater than or less than the width of the first metal layer, and after the buffer pattern is formed, the first metal layer and the second metal layer are removed by etching. When selecting an etching solution, it is not necessary to consider the corrosion of the etching solution to the buffer layer, so that the range of etching solutions is wider.

[0041] In one implementation, after providing an intermediate substrate and before sequentially forming a first metal layer and a second metal layer stacked on a first surface, the method for manufacturing a solar cell further includes:

[0042] forming a dielectric layer on the first surface of the intermediate substrate;

[0043] A hole is opened in the dielectric layer located in the electrode area.

[0044] In one implementation, the electrode structure is recessed at the opening, and during the packaging process, more packaging material is stored at the opening, which is more conducive to the adhesion between the electrode structure and the packaging material at the opening. And / or, the roughness of the electrode structure at the opening is greater than the roughness of the electrode structure at other positions. In this technical solution, the roughness of the electrode structure at the opening is relatively large. During the packaging process, the contact area between the electrode structure and the packaging material at the opening can be increased, and the adhesion between the electrode structure and the packaging material at the opening can be improved, thereby improving the firmness of the electrode structure packaging. And / or, at the opening, the first metal layer includes holes. In this technical solution, the holes included in the first metal layer can play a role in releasing stress, preventing problems such as loose welding and warping of the battery cell caused by the release of stress of the electrode structure when the electrode structure is welded to the interconnect, while saving the raw materials for forming the first metal layer.

[0045] In one implementation, after sequentially forming a stacked first metal layer and a second metal layer on the first surface and before scanning the isolation region with a laser, the method for manufacturing a solar cell further includes: forming a protective layer on a side of the second metal layer away from the intermediate substrate;

[0046] Scanning the isolation area with a laser to modify the second metal layer in the isolation area includes: scanning the isolation area with a laser to remove the protective layer in the isolation area and modifying the second metal layer in the isolation area.

[0047] In one implementation, after a first metal layer and a second metal layer are stacked in sequence on a first surface and before an isolation area is scanned using a laser, the method for manufacturing a solar cell further includes: forming a protective layer on a side of the second metal layer facing away from the intermediate substrate, and removing the protective layer located in the isolation area.

[0048] By adopting the above two technical solutions, the protective layer in the isolation area is removed and the protective layer in the electrode area is retained. In the process of using a corrosive liquid to clean the intermediate substrate after laser scanning, the metal layer in the electrode area is covered by the protective layer. Therefore, only the metal layer in the isolation area contacts and reacts with the corrosive liquid, thereby achieving complete removal of the first metal layer and the second metal layer in the isolation area. In addition, the metal layer in the electrode area is not prone to defects, such as holes and impurities, under the protection of the protective layer, thereby avoiding the corrosive liquid from reacting with the first metal layer through the above defects, thereby damaging the electrode structure.

[0049] In one implementation, the material of the protective layer includes at least one of polyvinylidene fluoride, polypropylene, polyethylene, polystyrene, polyetheretherketone, and polytetrafluoroethylene. The protective layer formed by the above materials has higher density and better protection effect. The thickness of the protective layer is 10nm to 500nm. At this time, the transparency of the protective layer is high. The existence of the protective layer will not reduce the optical performance of the solar cell, ensuring the photoelectric conversion efficiency of the solar cell. Or,

[0050] The material of the protective layer includes at least one of chitosan, silicone oil, polyvinylidene fluoride, stearic acid, paraffin, ink, non-water-soluble cellulose derivatives, and fluororesin. The protective layer is made of the above materials, and the process is simple, high-temperature heating is not required, energy is saved, and production efficiency is high. The thickness of the protective layer is 0.5μm to 3μm, which ensures the protective effect of the protective layer on the electrode area and further reduces the occurrence of defects in the metal layer in the electrode area.

[0051] In one implementation, the corrosive solution includes a corrosion inhibitor, which is used to fill defects in the protective layer to improve the compactness of the protective layer.

[0052] In one implementation, after cleaning the intermediate substrate after the laser scanning process with the etching liquid, the manufacturing method further includes:

[0053] The protective layer is removed to prevent the protective layer from affecting the welding effect between the electrode structure and the conductive member (welding strip or main grid).

[0054] In one implementation, the intermediate substrate includes a semiconductor substrate and a first doped semiconductor layer, the two opposite surfaces of the semiconductor substrate are respectively a first surface and a second surface, and the first doped semiconductor layer is disposed on the first surface;

[0055] The formed electrode structure includes a first electrode structure, which is located on a side of the first doped semiconductor layer away from the semiconductor substrate; along the width direction of the first electrode structure, the ratio of the width of the first electrode structure to the width of the first doped semiconductor layer is greater than or equal to 0.1 and less than or equal to 1.1.

[0056] By adopting the above technical solution, the light irradiated from the second surface to the semiconductor substrate will be reflected back to the semiconductor substrate by the first electrode structure when passing through the semiconductor substrate to irradiate the first electrode structure, so that the semiconductor substrate absorbs the light again. In this solution, since the ratio of the width of the first electrode structure to the width of the first doped semiconductor layer is greater than or equal to 0.1 and less than or equal to 1.1, the area of ​​the first doped semiconductor layer covered by the first electrode structure is larger. Therefore, compared with the case where the ratio of the width of the first electrode structure to the width of the first doped semiconductor layer is less than 0.1, the reflectivity of the light reflected by the first electrode structure to the semiconductor substrate in this solution is greater, thereby improving the absorption utilization rate of the solar cell for the light incident from the second surface and improving the photoelectric conversion efficiency. Moreover, since the ratio of the width of the first electrode structure to the width of the first doped semiconductor layer in the present embodiment is greater than or equal to 0.1 and less than or equal to 1.1, when the width of the first doped semiconductor layer is constant, the width of the first electrode structure in the present embodiment accounts for a relatively large proportion, that is, the width of the first battery layer is relatively large. Under the premise that the thickness of the first electrode structure remains unchanged, the wider the first electrode structure, the lower the transmission resistance and the lower the series resistance, thereby increasing the filling factor FF to improve the efficiency of the back contact battery; or, under the premise that the resistance of the first electrode structure remains unchanged, the thickness of the first electrode structure can be reduced due to the increase in the width of the first electrode structure, and the reduction in the thickness of the first electrode structure is conducive to improving the manufacturing efficiency of the first electrode structure.

[0057] In one implementation, a ratio of a width of the first electrode structure to a width of the first doped semiconductor layer is less than or equal to 1;

[0058] The orthographic projection of the first electrode structure on the first doped semiconductor layer is located within the boundary of the first doped semiconductor layer, and along the width direction of the first electrode structure, the distance between the edge of the first electrode structure and the edge of the first doped semiconductor layer on the same side is 0 to 40 μm. This arrangement can prevent the first electrode structure from being too wide and contacting another doped semiconductor layer of opposite conductivity type, resulting in leakage.

[0059] In one implementation, along the width direction of the first electrode structure, the absolute value of the difference in distance between any two points on the edge of the first electrode structure and the edge of the first doped semiconductor layer on the same side is ΔD1, 0≤ΔD1≤40 μm.

[0060] In one implementation, a ratio of a width of the first electrode structure to a width of the first doped semiconductor layer is greater than 1 and less than or equal to 1.1;

[0061] Along the width direction of the first doped semiconductor layer, the edge of the first electrode structure exceeds the edge of the first doped semiconductor layer on the same side by a distance of 0 to 10 μm. This technical solution ensures that a safe distance is reserved between the edge of the first electrode structure and the second doped semiconductor layer, further reducing the risk of leakage.

[0062] In one implementation, the electrode region includes a first electrode region and a second electrode region; the isolation region is disposed between the first electrode region and the second electrode region;

[0063] The intermediate substrate after laser scanning is cleaned by using a corrosive liquid, and the modified second metal layer and the first metal layer thereunder are removed by etching with the corrosive liquid, and the first metal layer and the second metal layer in the remaining electrode area form an electrode structure; comprising:

[0064] The intermediate substrate is cleaned with a corrosive solution, and the corrosive solution etches away the second metal layer located in the isolation area and the first metal layer thereunder. The first metal layer and the second metal layer in the remaining first electrode area form a first electrode structure, and the first metal layer and the second metal layer in the remaining second electrode area form a second electrode structure.

[0065] In one implementation, in the electrode structure, along the extension direction of the first metal layer, the boundary of the first metal layer extends in a wavy shape. By adopting this technical solution, the overall extension length of the first metal layer can be increased, thereby increasing the transmission path and area of ​​the carriers in the first metal layer, which is conducive to reducing the contact resistance. And / or,

[0066] In the electrode structure, the width of the first metal layer gradually increases in the direction close to the intermediate substrate. In this way, the contact area between the first metal layer and the semiconductor substrate is larger, which increases the adhesion between the first metal layer and the semiconductor substrate and helps to reduce the contact resistance. In addition, the side of the first metal layer will not be blocked by the upper surface of the first metal layer, so that more light can be irradiated to the side of the first metal layer, and then more light can be reflected to the semiconductor substrate, thereby improving the utilization rate of light.

[0067] In one implementation, the width of the laser irradiation is greater than or equal to the width of the isolation region; and / or,

[0068] The difference between the width of the laser irradiation and the width of the isolation area is 0 to 400 um, so as to prevent leakage between adjacent electrode structures and improve the transmission efficiency of carriers.

[0069] In one implementation, the width of the second metal layer in the electrode structure is greater than the width of the first metal layer away from the surface of the intermediate substrate. This arrangement can ensure that there is a larger contact area between the second metal layer of the electrode structure and the welding strip or interconnection component during the welding process, thereby improving the welding efficiency.

[0070] Alternatively, the width of the second metal layer in the electrode structure is equal to the width of the surface of the first metal layer away from the intermediate substrate. This arrangement can prevent the second metal layer from blocking the first metal layer, avoiding affecting the first metal layer's absorption of light, and the first metal layer from reflecting light toward the intermediate substrate.

[0071] Alternatively, the width of the second metal layer in the electrode structure is greater than the width of the surface of the first metal layer away from the intermediate substrate, and the difference between the width of the second metal layer in the electrode structure and the width of the surface of the first metal layer away from the intermediate substrate is in the range of 1μm to 30μm. With this technical solution, the edge of the second metal layer beyond the upper surface of the first metal layer is within a reasonable range, which not only ensures a larger contact area between the second metal layer of the electrode structure and the welding strip or interconnection part during welding, but also avoids the side of the first metal layer being blocked by the second metal layer, so that more light can be irradiated to the side of the first metal layer.

[0072] In one implementation, in the step of scanning the isolation region with laser, inert gas is blown toward the first surface during the process of scanning the isolation region with laser to protect the molten metal and the laser lens barrel.

[0073] In one implementation, the etching solution includes NaOH, KOH, HCl, H 2 SO 4 , HNO 3 , H 3 PO 4 , tetramethylammonium hydroxide and ammonia water. The above-mentioned types of etching liquid have good corrosion effect and low cost.

[0074] In one implementation, the first metal layer is formed by magnetron sputtering or evaporation; and / or the second metal layer is formed by magnetron sputtering or evaporation. The first metal layer and the second metal layer formed in the electrode region are thus highly dense, and when the second metal layer is used as a welding layer, the welding effect of the second metal layer is improved.

[0075] In one implementation, the first metal layer includes one or more of Al, Zn, Fe, Co, Mg, Cu, Ag and alloys thereof; and / or the second metal layer includes one or more of Cu, Ni, Cr, Ti, W, Mo, Ag, Sn and alloys thereof.

[0076] In one implementation, the difference between the standard electrode potential of the first metal layer and the standard electrode potential of the second metal layer is 0.1V to 3.5V, and the standard electrode potential of the first metal layer is less than the standard electrode potential of the second metal layer. In this way, during the wet etching process, the etching solution first corrodes the first metal layer, forming the shape of the side surface of the first metal layer while ensuring that the second metal layer is not severely corroded.

[0077] In one implementation, the thickness of the first metal layer is 0.5 μm to 20 μm, so as to ensure that the resistance of the electrode structure is small, the first metal layer is firmly bonded to the intermediate substrate, and the processing cost is reduced. And / or, the thickness of the second metal layer is 5 nm to 300 nm, so as to ensure that the second metal layer is firmly welded to the welding strip or interconnection member, and the selectivity of the laser in the laser patterning process is not limited.

[0078] And / or, the thickness of the second metal layer is less than or equal to 10% of the thickness of the first metal layer, so as to ensure that the second metal layer is firmly welded to the welding strip or interconnection member and facilitate patterning of the second metal layer, for example, making the laser used for laser patterning of the second metal layer more selective.

[0079] A method for manufacturing a solar cell, comprising:

[0080] Providing an intermediate substrate, the intermediate substrate comprising a first surface and a second surface opposite to each other, the first surface comprising an electrode region and an isolation region; the roughness of the isolation region of the intermediate substrate is greater than the roughness of the electrode region of the intermediate substrate;

[0081] A first metal layer and a second metal layer are sequentially stacked on the first surface, wherein the first metal layer is closer to the intermediate substrate than the second metal layer; the density of the second metal layer located in the isolation area is less than the density of the second metal layer located in the electrode area;

[0082] The intermediate substrate is cleaned with a corrosive liquid, and the corrosive liquid etches away the second metal layer located in the isolation area and the first metal layer thereunder, and the first metal layer and the second metal layer in the remaining electrode area form an electrode structure; wherein the corrosion resistance of the second metal layer to the corrosive liquid is greater than that of the first metal layer to the corrosive liquid.

[0083] In the manufacturing method of the solar cell, the difference in roughness between the isolation area and the electrode area is utilized to achieve that the density of the second metal layer in the isolation area is smaller than the density of the second metal layer in the electrode area, thereby facilitating patterning of the first metal layer and the second metal layer by etching with a corrosive liquid. Compared with the modification of the second metal layer by laser scanning in the first embodiment, laser scanning is not required, which saves energy and reduces processing costs.

[0084] In one implementation, after the first metal layer and the second metal layer are stacked in sequence on the first surface, and before the intermediate substrate is cleaned with a corrosive liquid, the method for manufacturing a solar cell further includes:

[0085] The isolation area is scanned by laser to modify the second metal layer in the isolation area, so that the first metal layer and the second metal layer in the isolation area can be removed more quickly by the etching liquid, thereby improving the processing efficiency of the solar cell.

[0086] In one implementation, the second metal layer located in the isolation region is modified by scanning the isolation region with a laser, including:

[0087] Scanning the isolation area with a laser so that the second metal layer located in the isolation area and the first metal layer thereunder form a metal alloy; the corrosion resistance of the metal alloy to the corrosive liquid is lower than that of the second metal layer to the corrosive liquid;

[0088] Alternatively, the second metal layer located in the isolation area is modified by scanning the isolation area with a laser, comprising:

[0089] Scanning the isolation region by laser so that the density of the second metal layer located in the isolation region is smaller than the density of the second metal layer located in the electrode region;

[0090] Alternatively, the second metal layer located in the isolation area is modified by scanning the isolation area with a laser, comprising:

[0091] Laser scanning is used to scan the isolation area so that a metal alloy is formed between the second metal layer located in the isolation area and the first metal layer thereunder, and the density of the metal alloy is lower than the density of the second metal layer located in the electrode area; wherein the corrosion resistance of the metal alloy to the corrosive liquid is lower than the corrosion resistance of the second metal layer to the corrosive liquid.

[0092] In one implementation, the width of the laser irradiation is greater than or equal to the width of the isolation region;

[0093] And / or, the difference between the width of the laser irradiation and the width of the isolation area is 0 to 400 um.

[0094] In one implementation, in the step of scanning the isolation region with laser, an inert gas is blown toward the first surface during the process of scanning the isolation region with laser.

[0095] In one implementation, the isolation region of the intermediate substrate is a suede structure, and the electrode region of the intermediate substrate is a polished surface structure.

[0096] In one implementation, after providing an intermediate substrate and before sequentially forming a first metal layer and a second metal layer stacked on a first surface, the method for manufacturing a solar cell further includes:

[0097] forming a transparent conductive layer on the first surface of the intermediate substrate;

[0098] The intermediate substrate is cleaned with a corrosive solution, and the corrosive solution etches and removes the modified second metal layer and the first metal layer thereunder, and the first metal layer and the second metal layer in the remaining electrode area form an electrode structure, including:

[0099] The intermediate substrate is cleaned with a corrosive solution, and the corrosive solution etches and removes the second metal layer located in the isolation area and the first metal layer and the transparent conductive layer thereunder, so that the first metal layer and the second metal layer in the remaining electrode area form an electrode structure, and the transparent conductive layer in the remaining electrode area forms a transparent conductive pattern;

[0100] Alternatively, the method for manufacturing a solar cell further comprises:

[0101] forming a transparent conductive layer on the first surface of the intermediate substrate, and patterning the transparent conductive layer to form a transparent conductive pattern;

[0102] The method sequentially forms a first metal layer and a second metal layer stacked on a first surface, comprising: forming the first metal layer and the second metal layer on an intermediate substrate formed with a transparent conductive pattern.

[0103] In one implementation, the corrosive liquid etches away the second metal layer located in the isolation area and the first metal layer and the transparent conductive layer thereunder, and the transparent conductive layer in the remaining electrode area forms a transparent conductive pattern; wherein the width of the transparent conductive pattern is equal to the width of the first metal layer;

[0104] or,

[0105] A transparent conductive layer is formed on the first surface of the intermediate substrate, and the transparent conductive layer is processed to form a transparent conductive pattern; wherein the width of the transparent conductive pattern is greater than or equal to the width of the first metal layer.

[0106] In one implementation, after providing an intermediate substrate and before sequentially forming a first metal layer and a second metal layer stacked on a first surface, the method for manufacturing a solar cell further includes:

[0107] forming a buffer layer on the first surface of the intermediate substrate;

[0108] The intermediate substrate is cleaned by using a corrosive liquid, and the corrosive liquid etches and removes the second metal layer and the first metal layer thereunder, and the first metal layer and the second metal layer in the remaining electrode area form an electrode structure; comprising:

[0109] The intermediate substrate is cleaned with an etching solution, and the etching solution removes the second metal layer located in the isolation area and the first metal layer and the buffer layer thereunder, so that the first metal layer and the second metal layer in the remaining electrode area form an electrode structure, and the buffer layer in the remaining electrode area forms a buffer pattern;

[0110] Alternatively, the method for manufacturing a solar cell further comprises:

[0111] forming a buffer layer on the first surface of the intermediate substrate, and patterning the buffer layer to form a buffer pattern;

[0112] The method comprises the following steps: forming a first metal layer and a second metal layer stacked in sequence on a first surface, comprising: forming the first metal layer and the second metal layer on an intermediate substrate having a buffer pattern formed thereon;

[0113] In one implementation, after providing an intermediate substrate and before sequentially forming a first metal layer and a second metal layer stacked on a first surface, the method for manufacturing a solar cell further includes:

[0114] forming a dielectric layer on the first surface of the intermediate substrate;

[0115] A hole is opened in the dielectric layer located in the electrode area.

[0116] In one implementation, the electrode structure is recessed at the opening; and / or the roughness of the electrode structure at the opening is greater than the roughness of the electrode structure at other locations; and / or the first metal layer includes a hole at the opening.

[0117] In one implementation, after the first metal layer and the second metal layer are stacked in sequence on the first surface and before the intermediate substrate is cleaned with a corrosive liquid, the method for manufacturing a solar cell further includes: forming a protective layer on a side of the second metal layer away from the intermediate substrate, and removing the protective layer located in the isolation area.

[0118] In one implementation, the material of the protective layer includes at least one of polyvinylidene fluoride, polypropylene, polyethylene, polystyrene, polyetheretherketone, and polytetrafluoroethylene, and the thickness of the protective layer is 10 nm to 500 nm; or,

[0119] The material of the protective layer includes at least one of chitosan, silicone oil, polyvinylidene fluoride, stearic acid, paraffin, ink, non-water-soluble cellulose derivatives, and fluororesin, and the thickness of the protective layer is 0.5 μm to 3 μm.

[0120] In one implementation, the corrosive solution includes a corrosion inhibitor, which is used to fill defects in the protective layer to improve the compactness of the protective layer.

[0121] In one implementation, after cleaning the intermediate substrate after the laser scanning process with the etching liquid, the manufacturing method further includes:

[0122] Remove the protective layer.

[0123] In one implementation, the electrode region includes a first electrode region and a second electrode region; the isolation region is disposed between the first electrode region and the second electrode region;

[0124] The intermediate substrate is cleaned by using a corrosive solution, and the corrosive solution etches and removes the second metal layer and the first metal layer thereunder, and the first metal layer and the second metal layer in the remaining electrode area form an electrode structure, including:

[0125] The intermediate substrate is cleaned with a corrosive solution, and the corrosive solution etches away the second metal layer located in the isolation area and the first metal layer thereunder. The first metal layer and the second metal layer in the remaining first electrode area form a first electrode structure, and the first metal layer and the second metal layer in the remaining second electrode area form a second electrode structure.

[0126] In one implementation, in the electrode structure, along the extension direction of the first metal layer, the boundary of the first metal layer extends in a wave shape;

[0127] And / or, in the electrode structure, the width of the first metal layer gradually increases along a direction approaching the intermediate substrate.

[0128] In one implementation, the width of the second metal layer in the electrode structure is greater than or equal to the width of the surface of the first metal layer away from the intermediate substrate;

[0129] Alternatively, the width of the second metal layer in the electrode structure is greater than the width of the first metal layer away from the intermediate substrate surface, and the difference between the width of the second metal layer in the electrode structure and the width of the first metal layer away from the intermediate substrate surface ranges from 1 μm to 30 μm.

[0130] In one implementation, the etching solution includes NaOH, KOH, HCl, H 2 SO 4 , HNO 3 , H 3 PO 4 , tetramethylammonium hydroxide and ammonia water.

[0131] In one implementation, the first metal layer includes one or more of Al, Zn, Fe, Co, Mg, Cu, Ag and alloys thereof; and / or the second metal layer includes one or more of Cu, Ni, Cr, Ti, W, Mo, Ag, Sn and alloys thereof.

[0132] In one implementation, the difference between the standard electrode potential of the first metal layer and the standard electrode potential of the second metal layer is 0.1V to 3.5V, and the standard electrode potential of the first metal layer is less than the standard electrode potential of the second metal layer.

[0133] In one implementation, the thickness of the first metal layer is 0.5 μm to 20 μm;

[0134] and / or, the thickness of the second metal layer is 5 nm to 300 nm;

[0135] And / or, the thickness of the second metal layer is less than or equal to 10% of the thickness of the first metal layer.

[0136] In one implementation, after the first metal layer and the second metal layer are stacked in sequence on the first surface and before the intermediate substrate is cleaned with a corrosive liquid, the method for manufacturing a solar cell further includes: forming a protective layer on a side of the second metal layer away from the intermediate substrate, and removing the protective layer located in the isolation area. BRIEF DESCRIPTION OF THE DRAWINGS

[0137] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0138] Figure 1 It is a top view SEM image of the electrode structure in the prior art;

[0139] Figure 2 Schematic diagram of the method for manufacturing a solar cell provided in an embodiment of the present application Figure 1 ;

[0140] Figure 3 Schematic diagram of the method for manufacturing a solar cell provided in an embodiment of the present application Figure 2 ;

[0141] Figure 4 Schematic diagram of the method for manufacturing a solar cell provided in an embodiment of the present application Figure 3 ;

[0142] Figure 5 Schematic diagram of the method for manufacturing a solar cell provided in an embodiment of the present application Figure 4 ;

[0143] Figure 6 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 1 ;

[0144] Figure 7 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 2 ;

[0145] Figure 8 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 3 ;

[0146] Fig. 9 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 1 ;

[0147] Fig.10 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 2 ;

[0148] Fig.11 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 3 ;

[0149] Fig.12 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 4 ;

[0150] Fig.13 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 1 ;

[0151] Fig.14 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 2 ;

[0152] Fig.15 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 3 ;

[0153] Fig.16 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 1 ;

[0154] Fig.17 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 2 ;

[0155] Fig.18 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 3 ;

[0156] Fig.19 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 1 ;

[0157] Fig. 20 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 2 ;

[0158] Fig.21 A schematic diagram of another method for manufacturing a solar cell provided in an embodiment of the present application Figure 3 ;

[0159] Fig. 22 A partial cross-sectional view of a solar cell formed by using the method for manufacturing a solar cell provided in an embodiment of the present application;

[0160] Fig.23 A partial cross-sectional view of another solar cell formed by using the method for manufacturing a solar cell provided in an embodiment of the present application;

[0161] Fig.24 A partial top view of a solar cell formed by the method for manufacturing a solar cell provided in an embodiment of the present application;

[0162] Fig.25 A partial cross-sectional view of another solar cell formed by using the solar cell manufacturing method provided in an embodiment of the present application.

[0163] Reference numerals:

[0164] 01-conductive residue, 1-intermediate substrate, 2-first metal layer, 3-second metal layer, 4-isolation area, 5-electrode area, 6-transparent conductive layer, 7-dielectric layer, 7a-through hole, 8-protective layer;

[0165] 10 - semiconductor substrate, 30 - first doped semiconductor layer, 40 - first interface layer, 50 - first electrode structure, 60 - second electrode structure, 70 - second doped semiconductor layer, 80 - second interface layer. DETAILED DESCRIPTION

[0166] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0167] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0168] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "multiple" means two or more, unless otherwise clearly and specifically defined. "Several" means one or more, unless otherwise clearly and specifically defined.

[0169] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0170] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0171] In the existing solar cell manufacturing process, the electrode structure of the solar cell is generally manufactured by screen printing. Figure 1 As shown, the screen printing process will result in many discretely distributed conductive residues 01 at the edge of each electrode structure. These conductive residues 01 are not in contact with the electrode, so they not only have no carrier extraction function, but also block light, affecting the collection of carriers. In addition, the electrodes are formed by screen printing or electroplating, and the main raw material of the electrodes is silver, resulting in a high cost of the electrode structure. In addition, the printing screen used in the screen printing process needs to be cleaned before it can be reused, and the process is complicated; the cost of electroplating equipment is high, resulting in a high cost of making electrodes.

[0172] In view of the above situation, in order to reduce the manufacturing cost of the electrode structure and improve the utilization rate of light, the present application provides a variety of solar cell manufacturing methods.

[0173] A method for manufacturing a solar cell includes: providing an intermediate substrate 1, the intermediate substrate 1 includes a first surface and a second surface relative to each other, the first surface includes an electrode region 5 and an isolation region 4; sequentially forming a stacked first metal layer 2 and a second metal layer 3 on the first surface, the first metal layer 2 being closer to the intermediate substrate 1 relative to the second metal layer 3; scanning the isolation region 4 with a laser to modify the second metal layer 3 located in the isolation region 4; cleaning the intermediate substrate 1 after the laser scanning process with a corrosive liquid, etching and removing the modified second metal layer 3 and the first metal layer 2 thereunder with the corrosive liquid, and forming an electrode structure with the remaining first metal layer 2 and second metal layer 3 in the electrode region 5; wherein the corrosion resistance of the second metal layer 3 to the corrosive liquid is greater than the corrosion resistance of the first metal layer 2 to the corrosive liquid.

[0174] Among them, another method for manufacturing a solar cell includes: providing an intermediate substrate 1, the intermediate substrate 1 includes a first surface and a second surface relative to each other, the first surface includes an electrode area 5 and an isolation area 4; the roughness of the isolation area 4 of the intermediate substrate 1 is greater than the roughness of the electrode area 5 of the intermediate substrate 1; sequentially forming a stacked first metal layer 2 and a second metal layer 3 on the first surface, the first metal layer 2 is closer to the intermediate substrate 1 relative to the second metal layer 3; the density of the second metal layer 3 located in the isolation area 4 is less than the density of the second metal layer 3 located in the electrode area 5; cleaning the intermediate substrate 1 with a corrosive liquid, the corrosive liquid etches and removes the second metal layer 3 located in the isolation area 4 and the first metal layer 2 thereunder, and the remaining first metal layer 2 and second metal layer 3 in the electrode area 5 form an electrode structure; wherein the corrosion resistance of the second metal layer 3 to the corrosive liquid is greater than the corrosion resistance of the first metal layer 2 to the corrosive liquid.

[0175] The specific structure and preparation method of the above-mentioned back contact battery are introduced in detail through several specific embodiments below.

[0176] Embodiment 1:

[0177] The method for manufacturing a solar cell provided in the first embodiment of the present application includes:

[0178] S100: Figure 2 As shown, an intermediate substrate 1 is provided. The intermediate substrate 1 includes a first surface and a second surface opposite to each other. The first surface includes an electrode region 5 and an isolation region 4 .

[0179] like Figure 2 As shown, at least one intermediate substrate 1 is provided. The intermediate substrate 1 may include a semiconductor substrate and a semiconductor doping layer disposed on the semiconductor substrate, and the semiconductor doping layer is at least disposed on a first surface. The intermediate substrate 1 includes a first surface and a second surface opposite to each other. In practical applications, the first surface may be a light-facing surface and the second surface may be a backlight surface; or the first surface may be a backlight surface and the second surface may be a light-facing surface.

[0180] The first surface includes an electrode region 5 and an isolation region 4, wherein the electrode region 5 is used to manufacture and form an electrode structure, and the isolation region 4 is used to isolate two adjacent electrode structures to prevent leakage.

[0181] S200: Figure 3 As shown, a first metal layer 2 and a second metal layer 3 are stacked in sequence on the first surface, and the first metal layer 2 is closer to the intermediate substrate 1 than the second metal layer 3 .

[0182] In this step, a first metal layer 2 may be formed as a whole layer on the first surface of the intermediate substrate 1 , and then a second metal layer 3 may be formed as a whole layer.

[0183] S300: Figure 4 As shown, the isolation region 4 is scanned by laser to modify the second metal layer 3 located in the isolation region 4 .

[0184] In this step, the laser may be moved along the extension direction of the isolation region 4 to scan the isolation region 4 , or the laser may be moved back and forth along the width direction of the isolation region 4 to scan the isolation region 4 .

[0185] S400: Figure 5 As shown, the intermediate substrate 1 after laser scanning processing is cleaned by using a corrosive liquid, and the corrosive liquid etches away the modified second metal layer 3 and the first metal layer 2 thereunder, and the first metal layer 2 and the second metal layer 3 in the remaining electrode region 5 form an electrode structure, that is, the corrosive liquid etches away the second metal layer 3 in the isolation region 4 and the first metal layer 2 thereunder, and the first metal layer 2 and the second metal layer 3 in the electrode region 5 are retained to form an electrode structure; wherein the corrosion resistance of the second metal layer 3 to the corrosive liquid is greater than the corrosion resistance of the first metal layer 2 to the corrosive liquid.

[0186] Among them, the corrosion resistance of the second metal layer 3 to the corrosive liquid is greater than that of the first metal layer 2 to the corrosive liquid, which is beneficial for the corrosive liquid to etch and remove the modified second metal layer 3 and the first metal layer 2 thereunder, while the unmodified second metal layer 3 will not be corroded, so that the unmodified second metal layer 3 can protect the first metal layer 2 thereunder.

[0187] In the solar cell structure formed by the above-mentioned solar cell manufacturing method, since the first metal layer 2 is covered by the second metal layer 3, and the corrosion resistance of the second metal layer 3 before modification to the corrosive liquid is greater than that of the first metal layer 2 to the corrosive liquid, the second metal layer 3 can protect the first metal layer 2 and prevent the first metal layer 2 from being corroded. In addition, the electrode structure of the present application includes two metal layers, the first metal layer 2 can be formed by a metal with low cost and not resistant to corrosion by the corrosive liquid, and the second metal layer 3 can be formed by a metal resistant to corrosion by the corrosive liquid. Compared with the prior art in which the electrode structure is an integrated structure and all metals resistant to corrosion by the corrosive liquid are selected, the selectivity of the first metal layer 2 is increased, and the manufacturing cost of the electrode structure is reduced by selecting a metal with low cost to form the first metal layer 2.

[0188] In addition, the electrode structure of the solar cell includes a first metal layer 2 and a second metal layer 3, wherein the second metal layer 3 can be used as a welding layer, the second metal layer 3 can be made of a weldable metal material, and the first metal layer 2 can be made of a metal material with low cost and good conductivity. Compared with the electrode structure in the prior art as an integrated structure, since the first metal layer 2 and the second metal layer 3 can be made of different materials as needed, different functions can be achieved.

[0189] In the manufacturing method of the solar cell described above, the second metal layer 3 of the isolation region 4 is first modified by laser scanning, and then the first metal layer 2 and the second metal layer 3 are patterned by etching with a corrosive liquid. The width of the electrode structure can be accurately controlled by controlling the diameter of the laser spot, so that the size of the electrode structure finally prepared is also more accurate. In addition, the present application can use the corrosive liquid to completely remove the first metal layer 2 and the second metal layer 3 in the isolation region 4. Compared with the electrode structure formed by printing in the prior art, it can prevent more conductive residues from remaining in the isolation region 4, avoid more conductive residues from blocking light, improve light utilization, and improve carrier collection efficiency. Moreover, compared with printing to form an electrode structure, there is no need to repeatedly clean the screen, which simplifies the process; compared with electroplating to form an electrode structure, the equipment cost of forming the electrode structure is reduced, and the electroplating solution is avoided from polluting the environment.

[0190] In the first embodiment, step S300: scanning the isolation region 4 with a laser to modify the second metal layer 3 located in the isolation region 4 includes:

[0191] S301: Scan the isolation area 4 with laser to form a metal alloy between the second metal layer 3 located in the isolation area 4 and the first metal layer 2 thereunder; the corrosion resistance of the metal alloy to the corrosive liquid is lower than that of the second metal layer 3 to the corrosive liquid.

[0192] In step S301, laser scanning is used to form a metal alloy between the second metal layer 3 in the isolation region 4 and the first metal layer 2 below the second metal layer 3. In this step, the modification of the second metal layer 3 located in the isolation region 4 includes forming a metal alloy at least in part of the second metal layer 3. It should be noted that after the laser scanning process, the isolation region 4 may only include the metal alloy, in which case both the first metal layer 2 and the second metal layer 3 form a metal alloy; or, after the laser scanning process, the isolation region 4 may include the metal alloy and the first metal layer 2, in which case the second metal layer 3 forms a metal alloy, and the first metal layer 2 does not completely form a metal alloy; or, after the laser scanning process, the isolation region 4 may include the metal alloy and the second metal layer 3, in which case the first metal layer 2 forms a metal alloy, and the second metal layer 3 does not completely form a metal alloy; or, after the laser scanning process, the isolation region 4 may include the metal alloy, the first metal layer 2 and the second metal layer 3, in which case both the first metal layer 2 and the second metal layer 3 do not completely form a metal alloy.

[0193] Among them, the corrosion resistance of the metal alloy to the corrosive liquid is lower than that of the second metal layer 3. In this way, when the intermediate substrate is placed in the corrosive liquid, the corrosive liquid will corrode the metal alloy. In the case where the first metal layer 2 still remains in the isolation area 4, the first metal layer 2 will also be corroded by the corrosive liquid due to its poor corrosion resistance. In the case where the second metal layer 3 still remains in the isolation area 4, since the corrosive liquid corrodes the metal alloy, the second metal layer 3 remaining in the isolation area and the second metal layer 3 in the electrode area 5 will be disconnected from each other. While the corrosive liquid corrodes the metal alloy, the second metal layer 3 remaining in the isolation area will also be taken away.

[0194] It should be noted that since the corrosion resistance of the second metal layer 3 to the corrosive liquid is greater than the corrosion resistance of the first metal layer 2 to the corrosive liquid and the corrosion resistance of the metal alloy to the corrosive liquid, when the corrosive liquid is used to clean the intermediate substrate after laser scanning processing, the corrosive liquid will not corrode the area not irradiated by the laser, that is, the second metal layer 3 in the electrode area and the first metal layer 2 under the second metal layer 3.

[0195] Alternatively, in the above-mentioned first embodiment, step S300: scanning the isolation region 4 with a laser to modify the second metal layer 3 located in the isolation region 4 comprises:

[0196] S302 : Scan the isolation region 4 using laser to make the density of the second metal layer 3 located in the isolation region 4 smaller than the density of the second metal layer 3 located in the electrode region 5 .

[0197] In step S302, laser scanning is used to reduce the density of the second metal layer 3 in the isolation area 4 to a level lower than the density of the second metal layer 3 in the electrode area 5. It can be understood that the lower the density, that is, the looser the second metal layer 3, the more likely it is that the corrosive liquid can penetrate the first metal layer 2 underneath through the loose second metal layer 3, and react with the first metal layer 2 underneath to remove the first metal layer 2 in the isolation area 4. Since the first metal layer 2 in the isolation area irradiated by the laser is corroded, and the second metal layer 3 above it is relatively loose, the second metal layer 3 in the isolation area will be carried away by the corrosive liquid during the corrosion process, especially when the thickness of the second metal layer 3 is relatively thin, or when steps such as purging and ultrasonic cleaning are added, the second metal layer 3 in the isolation area is more easily removed, and the first metal layer 2 and the second metal layer 3 in the electrode area 5 are retained to form an electrode structure.

[0198] Alternatively, in the above-mentioned first embodiment, step S300: scanning the isolation region 4 with a laser to modify the second metal layer 3 located in the isolation region 4 comprises:

[0199] S303: Use laser scanning to scan the isolation area 4 so that the second metal layer 3 located in the isolation area 4 and the first metal layer 2 thereunder form a metal alloy, and the density of the metal alloy is lower than the density of the second metal layer 3 located in the electrode area 5; wherein the corrosion resistance of the metal alloy to the corrosive liquid is lower than the corrosion resistance of the second metal layer 3 to the corrosive liquid.

[0200] The metal alloy formed in the isolation area 4 by laser irradiation contains the metal elements of the first metal layer 2, so the corrosion resistance of the metal alloy to the corrosive liquid is lower than that of the second metal layer 3 to the corrosive liquid. At the same time, the density of the metal alloy is lower than the density of the second metal layer 3 located in the electrode area 5. Therefore, the corrosive liquid can more quickly and completely remove the metal alloy with poor corrosion resistance and low density in the isolation area 4.

[0201] It should be noted that after laser scanning processing, the isolation area 4 may only include metal alloys, in which case the first metal layer 2 and the second metal layer 3 both form metal alloys; or, after laser scanning processing, the isolation area 4 may include metal alloys and the first metal layer 2, in which case the second metal layer 3 forms a metal alloy, and the first metal layer 2 has not completely formed a metal alloy; or, after laser scanning processing, the isolation area 4 may include metal alloys and the second metal layer 3, in which case the first metal layer 2 forms a metal alloy, and the second metal layer 3 has not completely formed a metal alloy; or, after laser scanning processing, the isolation area 4 may include metal alloys, the first metal layer 2 and the second metal layer 3, in which case the first metal layer 2 and the second metal layer 3 have not completely formed a metal alloy.

[0202] In addition, in this embodiment 1, the power of the laser can be 10w~150w. Exemplarily, the power of the laser is 10w, 20w, 30w, 40w, 50w, 60w, 70w, 80w, 90w, 100w, 110w, 120w, 130w, 140w or 1500w.

[0203] The frequency of the laser is 500 KHz to 4000 KHz. Exemplarily, the frequency of the laser is 500 KHz, 1000 KHz, 1500 KHz, 2000 KHz, 2500 KHz, 3000 KHz, 3500 KHz or 4000 KHz.

[0204] The pulse width of the laser is 10 ps to 20 ps. Exemplarily, the pulse width of the laser is 10 ps, ​​11 ps, 12 ps, 13 ps, 14 ps, 15 ps, 16 ps, 17 ps, 18 ps, 19 ps or 20 ps.

[0205] The wavelength of the laser is 300 nm to 1200 nm. Exemplarily, the wavelength of the laser is 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm or 1200 nm.

[0206] The laser spot diameter or spot width is 10 μm to 400 μm. Exemplarily, the laser spot diameter or spot width is 10 μm, 50 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm or 400 μm.

[0207] By setting the laser's reasonable power, frequency, pulse width and other parameters in this way, the laser can modify the second metal layer 3 in the isolation area 4, thereby preventing insufficient laser intensity or other unreasonable parameters from affecting the modification of the second metal layer 3 in the isolation area 4.

[0208] In some examples of the first embodiment, the roughness of the isolation region 4 of the intermediate substrate 1 is greater than the roughness of the electrode region 5 of the intermediate substrate 1. Moreover, before the second metal layer 3 located in the isolation region 4 is modified, the density of the second metal layer 3 located in the isolation region 4 is less than the density of the second metal layer 3 located in the electrode region 5. In this way, it is more conducive to the corrosion liquid to penetrate the second metal layer 3 in the isolation region 4 and contact and react with the first metal layer 2 thereunder, so as to remove the first metal layer 2 in the isolation region 4, and in this process, the second metal layer 3 with lower density will also gradually loosely deposit in the corrosion liquid, especially when the thickness of the second metal layer 3 is thin, or when the steps of purging, ultrasonic cleaning, etc. are added, the second metal layer 3 in the isolation region is more easily removed.

[0209] In some embodiments, the isolation region 4 of the intermediate substrate 1 may have a suede structure, and the electrode region 5 of the intermediate substrate 1 may have a polished surface structure.

[0210] Embodiment 2:

[0211] The manufacturing method of the solar cell provided in the second embodiment of the present application includes:

[0212] S100 ′: providing an intermediate substrate 1 , the intermediate substrate 1 comprising a first surface and a second surface opposite to each other, the first surface comprising an electrode region 5 and an isolation region 4 ; the roughness of the isolation region 4 of the intermediate substrate 1 is greater than the roughness of the electrode region 5 of the intermediate substrate 1 .

[0213] The difference between this step S100' and step S100 in the first embodiment is that the roughness of the isolation region 4 of the intermediate substrate 1 is greater than the roughness of the electrode region 5 of the intermediate substrate 1. It can be understood that when the roughness of the isolation region 4 of the intermediate substrate 1 is relatively large, in the process of forming the first metal layer 2 and the second metal layer 3, the formation quality of the first metal layer 2 and the second metal layer 3 in the isolation region 4 is relatively poor, and the adhesion of the first metal layer 2 and the second metal layer 3 in the isolation region 4 is relatively poor and the density is relatively low, so that it is more conducive for the etching liquid to penetrate the second metal layer 3 in the isolation region 4 and contact and react with the first metal layer 2 thereunder, and remove the first metal layer 2 in the isolation region 4. In this process, the second metal layer 3 with relatively low density will also gradually and loosely deposit in the etching liquid, especially when the thickness of the second metal layer 3 is relatively thin, or when the steps of purging, ultrasonic cleaning, etc. are added, the second metal layer 3 in the isolation region is more easily removed.

[0214] In addition, the remaining features of step S100' can refer to step S100 in the first embodiment, and will not be described in detail here.

[0215] S200 ′: a first metal layer 2 and a second metal layer 3 are stacked in sequence on the first surface, wherein the first metal layer 2 is closer to the intermediate substrate 1 than the second metal layer 3 ; the density of the second metal layer 3 located in the isolation area 4 is less than the density of the second metal layer 3 located in the electrode area 5 .

[0216] Next, in this step, a first metal layer 2 may be formed on the first surface of the intermediate substrate 1, and then a second metal layer 3 may be formed. Furthermore, since the roughness in the isolation region 4 is greater than the roughness in the electrode region 5, the density of the second metal layer 3 in the isolation region 4 is less than that in the electrode region 5, and the density of the first metal layer 2 in the isolation region 4 is less than that in the electrode region 5.

[0217] S300': The intermediate substrate 1 is cleaned with a corrosive liquid, and the corrosive liquid etches away the second metal layer 3 located in the isolation area 4 and the first metal layer 2 thereunder. The first metal layer 2 and the second metal layer 3 in the remaining electrode area 5 form an electrode structure; wherein the corrosion resistance of the second metal layer 3 to the corrosive liquid is greater than the corrosion resistance of the first metal layer 2 to the corrosive liquid.

[0218] Next, the intermediate substrate 1 is cleaned with an etching liquid, and the etching liquid penetrates the second metal layer 3 in the isolation region 4 and contacts and reacts with the first metal layer 2 thereunder, thereby removing the first metal layer 2 in the isolation region 4. In this process, the second metal layer 3 with a lower density may also gradually and loosely deposit in the etching liquid, thereby removing the second metal layer 3 in the isolation region 4 and the first metal layer 2 thereunder, and retaining the first metal layer 2 and the second metal layer 3 in the electrode region 5 to form an electrode structure. It can be understood that along the length direction of the electrode structure, the boundary of the electrode structure is roughly parallel to the boundary of the isolation region 4, and the width of the electrode structure is the same as the width of the electrode region 5.

[0219] Among them, the corrosion resistance of the second metal layer 3 to the corrosive liquid is greater than that of the first metal layer 2 to the corrosive liquid. In this way, the first metal layer 2 can be formed by a metal with low cost and not resistant to corrosion by the corrosive liquid, and the second metal layer 3 can be formed by a metal resistant to corrosion by the corrosive liquid. Compared with the prior art in which the electrode structure is an integrated structure and all of it is formed by metals resistant to corrosion by the corrosive liquid, the selectivity of the first metal layer 2 is increased, and by selecting a metal with low cost to form the first metal layer 2, the manufacturing cost of the electrode structure is reduced.

[0220] In addition, as mentioned above, since the roughness in the isolation region 4 is greater than the roughness in the electrode region 5, the density of the second metal layer 3 in the isolation region 4 is less than the density of the second metal layer 3 in the electrode region 5. The lower the density, the easier it is for the etching liquid to pass through. Therefore, the etching liquid is more likely to penetrate the second metal layer 3 in the isolation region 4 and react with the first metal layer 2 thereunder, removing the first metal layer 2 in the isolation region 4 and taking away the second metal layer 3 with lower density, thereby facilitating the patterning of the first metal layer 2 and the second metal layer 3. In this way, the first metal layer 2 and the second metal layer 3 in the isolation region 4 can be completely removed. Compared with the electrode structure formed by printing in the prior art, it can prevent more conductive residues from remaining in the isolation region 4, avoid more conductive residues from blocking light, improve light utilization, and improve carrier collection efficiency.

[0221] In addition, in the manufacturing method of the solar cell, the difference in roughness between the isolation area 4 and the electrode area 5 is utilized to achieve that the density of the second metal layer 3 in the isolation area 4 is less than the density of the second metal layer 3 located in the electrode area 5, thereby facilitating the patterning of the first metal layer 2 and the second metal layer 3 by etching with a corrosive liquid. Compared with the modification of the second metal layer 3 by laser scanning in Example 1, laser scanning is not necessary, which saves energy and reduces processing costs.

[0222] In the above-mentioned second embodiment, after the first metal layer 2 and the second metal layer 3 are stacked in sequence on the first surface in step S200', before the intermediate substrate 1 is cleaned with the etching solution in step S300', the manufacturing method of the solar cell further includes: S201' scanning the isolation region 4 with a laser to modify the second metal layer 3 located in the isolation region 4. In this step, the laser can be moved along the extension direction of the isolation region 4 to scan the isolation region 4, or the laser can be moved back and forth along the width direction of the isolation region 4 to scan the isolation region 4. Among them, the corrosion resistance of the second metal layer 3 to the etching solution is greater than the corrosion resistance of the first metal layer 2 to the etching solution.

[0223] In the above-mentioned manufacturing method of the solar cell, S201' is added to use laser scanning to modify the second metal layer 3 located in the isolation area 4. In this way, when the density of the second metal layer 3 located in the isolation area 4 is less than the density of the second metal layer 3 located in the electrode area 5, the second metal layer 3 in the isolation area 4 is further modified by laser scanning, thereby further reducing the corrosion resistance of the corrosive liquid in the isolation area 4, and finally achieving faster corrosion and removal of the first metal layer 2 and the second metal layer 3 in the isolation area 4 by the corrosive liquid, thereby improving the processing efficiency of the solar cell.

[0224] It can be understood that, since the compactness of the second metal layer 3 located in the isolation area 4 is already less than the compactness of the second metal layer 3 located in the electrode area 5 before the laser is used to scan the isolation area 4 in this method, even if the laser is not used to scan the isolation area 4, the first metal layer 2 and the second metal layer 3 in the isolation area 4 can be removed by the corrosive liquid. The laser scanning of the isolation area 4 is used here only to speed up the speed of the corrosive liquid corroding and removing the first metal layer 2 and the second metal layer 3 in the isolation area 4, thereby improving the manufacturing efficiency of solar energy. Therefore, in some examples, the intensity of the laser used can be lower than the laser intensity used in the first embodiment to save energy and reduce costs. For example, the laser wavelength is 532nm, the power is 30W-50W, and the scanning speed is 20-50m / s; or, the laser wavelength is 1046nm, the power is 40W-80W, and the scanning speed is 20-50m / s.

[0225] In some embodiments, S201 ′: scanning the isolation region 4 with a laser to modify the second metal layer 3 located in the isolation region 4 includes:

[0226] S201a': Scan the isolation area 4 with laser to form a metal alloy with the second metal layer 3 located in the isolation area 4 and the first metal layer 2 thereunder; the corrosion resistance of the metal alloy to the corrosive liquid is lower than that of the second metal layer 3 to the corrosive liquid.

[0227] The step S201a' is the same as the step S301 in the first embodiment, so the relevant contents of the above step S301 may be referred to and will not be described again.

[0228] Alternatively, S201′ utilizes laser scanning to modify the second metal layer 3 located in the isolation region 4, including:

[0229] S201 b ′: Scan the isolation region 4 with a laser, so that the density of the second metal layer 3 located in the isolation region 4 is smaller than the density of the second metal layer 3 located in the electrode region 5 .

[0230] The step S201b' is the same as the step S302 in the first embodiment, so the relevant contents of the above step S302 may be referred to and will not be described again.

[0231] Alternatively, S201′ utilizes laser scanning to modify the second metal layer 3 located in the isolation region 4, including:

[0232] S201c': Use laser scanning to scan the isolation area 4 so that the second metal layer 3 located in the isolation area 4 and the first metal layer 2 thereunder form a metal alloy, and the density of the metal alloy is lower than the density of the second metal layer 3 located in the electrode area 5; wherein the corrosion resistance of the metal alloy to the corrosive liquid is lower than the corrosion resistance of the second metal layer 3 to the corrosive liquid.

[0233] The step S201c' is the same as the step S302 in the first embodiment, so the relevant contents of the above step S303 may be referred to and will not be described again.

[0234] In some embodiments, the isolation region 4 of the intermediate substrate 1 may be a velvet structure, wherein the velvet structure may be an inverted pyramid velvet structure, or a positive pyramid velvet structure, or of course a wormhole velvet structure. The electrode region 5 of the intermediate substrate 1 may be a polished surface structure. The portion of the first metal layer 2 and the second metal layer 3 corresponding to the isolation region 4 will fluctuate with the fluctuation of the velvet structure, that is, the first metal layer 2 and the second metal layer 3 formed in the isolation region 4 also have roughly the same undulating morphology as the velvet structure. Therefore, when the isolation region 4 is a velvet structure, the first metal layer 2 and the second metal layer 3 formed in the isolation region 4 also have corresponding uneven features, which can reduce the formation quality of the first metal layer 2 and the second metal layer 3 in the isolation region 4, reduce the adhesion and compactness of the first metal layer 2 and the second metal layer 3 in the isolation region 4, and thus facilitate the rapid etching and removal of the first metal layer 2 and the second metal layer 3 in the isolation region 4 by the corrosive liquid.

[0235] Embodiment three:

[0236] The manufacturing method of the solar cell provided in the third embodiment of the present application includes steps S100 to S400 in the first embodiment, except that, in the manufacturing method of the solar cell, step S101 is added after step S100 and before step S200. And step S400 is replaced by step Sa, or, in step S200, the first metal layer 2 and the second metal layer 3 stacked in sequence on the first surface are replaced by step Sb.

[0237] Alternatively, the method for manufacturing a solar cell provided in the third embodiment of the present application includes steps S100' to S300' in the second embodiment, except that, in the method for manufacturing a solar cell, a step S101 is added after step S100' and before step S200'. And step S300' is replaced by step Sa, or, in step S200', the first metal layer 2 and the second metal layer 3 stacked in sequence on the first surface are replaced by step Sb.

[0238] In one case of the third embodiment, S101: forming a transparent conductive layer 6 on the first surface of the intermediate substrate 1. Specifically, Figure 6 As shown, a whole transparent conductive layer 6 can be formed on the first surface of the intermediate substrate 1. The transparent conductive layer 6 has a high conductivity and can timely guide the collected carriers to reduce the carrier recombination rate.

[0239] In the case that only the entire transparent conductive layer 6 is formed in step S101 and the transparent conductive layer 6 is not patterned to form a transparent conductive pattern, step S400 or step S300 ′ is replaced by step Sa.

[0240] Sa: The intermediate substrate 1 is cleaned with a corrosive liquid, and the corrosive liquid etches away the second metal layer 3 located in the isolation area 4 and the first metal layer 2 and the transparent conductive layer 6 thereunder. The first metal layer 2 and the second metal layer 3 in the remaining electrode area 5 form an electrode structure, and the transparent conductive layer 6 in the remaining electrode area 5 forms a transparent conductive pattern.

[0241] like Figure 8 As shown, in the Sa step, the etching liquid etches and removes the first metal layer 2, the second metal layer 3 and the transparent conductive layer 6 in the isolation area 4 together, that is, in this step, the first metal layer 2, the second metal layer 3 and the transparent conductive layer 6 are patterned together, avoiding the patterning of the transparent conductive layer 6 alone, simplifying the processing technology and improving the processing efficiency. In addition, since the first metal layer 2, the second metal layer 3 and the transparent conductive layer 6 are patterned together in this step, the width of the transparent conductive pattern is equal to the width of the first metal layer 2, ensuring that the transparent conductive layer 6 can be completely in contact with the bottom surface of the electrode structure, while preventing the transparent conductive layer 6 from being too large to block light or, when the electrode structure is applied to a back contact battery, the transparent conductive layer 6 is in contact with another doped semiconductor layer of the opposite conductivity type, resulting in leakage.

[0242] The width of the transparent conductive pattern may refer to the average width or the maximum width of the transparent conductive pattern; the width of the first metal layer 2 may refer to the average width or the maximum width of the first metal layer 2 .

[0243] Or, in another case in the third embodiment,

[0244] S101: forming a transparent conductive layer 6 on the first surface of the intermediate substrate 1, and patterning the transparent conductive layer 6 to form a transparent conductive pattern. Specifically, a whole layer of transparent conductive layer 6 may be formed on the first surface of the intermediate substrate 1, and then the whole layer of transparent conductive layer 6 may be processed by laser etching, wet etching or etching paste etching to form a transparent conductive pattern.

[0245] In the case where the transparent conductive pattern has been formed in step S101 , “forming a first metal layer 2 and a second metal layer 3 stacked in sequence on the first surface” in step S200 or S200 ′ is replaced by step Sb.

[0246] Sb: A first metal layer 2 and a second metal layer 3 are formed on an intermediate substrate 1 having a transparent conductive pattern. That is, in this step, a first metal layer 2 and a second metal layer 3 are formed to cover the transparent conductive pattern, so that the transparent conductive layer 6 is first patterned, and then the first metal layer 2 and the second metal layer 3 are formed. In this method, the width of the transparent conductive pattern can be greater than or equal to the width of the first metal layer 2, or can be less than the width of the first metal layer 2, and after the transparent conductive pattern is formed, the first metal layer and the second metal layer are removed by etching, and when selecting the etching solution, it is not necessary to consider its corrosiveness to the transparent conductive layer, so that the range of selection of the etching solution is wider.

[0247] In some examples of this embodiment, the width of the transparent conductive pattern formed in step S101 is greater than or equal to the width of the first metal layer 2, and the orthographic projection of the first metal layer 2 on the transparent conductive pattern is located within the boundary of the transparent conductive pattern, so that the bottom of the first metal layer 2 is completely in contact with the transparent conductive pattern, reducing the contact resistance of the bottom surface of the first metal layer 2 and further improving the carrier extraction rate. In addition, after the electrode structure is formed, it can be prevented from exceeding the boundary of the transparent conductive pattern, thereby preventing the transparent conductive layer 6 from contacting another doped semiconductor layer of opposite conductivity type when the electrode structure is applied to a back contact battery, resulting in leakage.

[0248] When the width of the transparent conductive pattern is greater than the width of the electrode structure, and the orthographic projection of the first metal layer 2 on the transparent conductive pattern is within the boundary of the transparent conductive pattern, the difference between the width of the transparent conductive pattern and the width of the electrode structure is greater than 0 and less than or equal to 30 μm. To ensure that the transparent conductive pattern can be in full contact with the bottom surface of the electrode structure, it is prevented that the transparent conductive pattern is too large to block light or when the electrode structure is applied to a back contact battery, the transparent conductive pattern contacts another doped semiconductor layer of the opposite conductivity type, resulting in leakage. Exemplarily, the difference between the width of the transparent conductive pattern and the width of the lower surface of the first metal layer 2 is greater than 0 and less than or equal to 30 μm, and can be 0, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm or 30 μm. In some examples, the difference between the width of the transparent conductive pattern and the width of the lower surface of the first metal layer 2 is greater than 0 and less than or equal to 10 μm.

[0249] For the above-mentioned transparent conductive layer 6, the embodiment of the present invention does not specifically limit the material and thickness of the transparent conductive layer 6. Exemplarily, the material of the transparent conductive layer 6 may include at least one of fluorine-doped tin oxide, aluminum-doped zinc oxide, tin-doped indium oxide, tungsten-doped indium oxide, molybdenum-doped indium oxide, cerium-doped indium oxide, indium hydroxide, titanium nitride, cadmium oxide, cuprous oxide, and fluorine-doped zinc oxide.

[0250] Exemplarily, the thickness of the transparent conductive layer 6 may be greater than or equal to 10 nm and less than or equal to 100 nm.

[0251] Embodiment 4:

[0252] The manufacturing method of the solar cell provided in the fourth embodiment of the present application includes steps S100 to S400 in the first embodiment, except that, in the manufacturing method of the solar cell, step S102 is added after step S100 and before step S200. And step S400 is replaced by step Sa', or, in step S200, the first metal layer 2 and the second metal layer 3 stacked in sequence on the first surface are replaced by step Sb'.

[0253] Alternatively, the method for manufacturing a solar cell provided in the fourth embodiment of the present application includes steps S100' to S300' in the second embodiment, except that, in the method for manufacturing a solar cell, step S102 is added after step S100' and before step S200'. Step S300' is replaced by step Sa', or, in step S200', the first metal layer 2 and the second metal layer 3 stacked in sequence on the first surface are replaced by step Sb'.

[0254] In one case of the fourth embodiment, S102: forming a buffer layer on the first surface of the intermediate substrate 1. Specifically, a whole layer of the buffer layer can be first formed on the first surface of the intermediate substrate 1. The buffer layer facilitates the deposition of the first metal layer 2 and improves the adhesion between the electrode structure and the intermediate substrate 1.

[0255] In the case that only a whole buffer layer is formed in step S102 and the buffer layer is not patterned to form a buffer pattern, step S400 or step S300 ′ is replaced by step Sa′.

[0256] Sa': The intermediate substrate 1 is cleaned with a corrosive solution, and the corrosive solution etches away the second metal layer 3 located in the isolation area 4 and the first metal layer 2 and the buffer layer thereunder. The first metal layer 2 and the second metal layer 3 in the remaining electrode area 5 form an electrode structure, and the buffer layer in the remaining electrode area 5 forms a buffer pattern.

[0257] In the Sa' step, the etching liquid etches and removes the first metal layer 2, the second metal layer 3 and the buffer layer in the isolation area 4 together, that is, in this step, the first metal layer 2, the second metal layer 3 and the buffer layer are patterned together, avoiding the patterning of the buffer layer alone, simplifying the processing technology and improving the processing efficiency. In addition, since the first metal layer 2, the second metal layer 3 and the buffer layer are patterned together in this step, the width of the buffer pattern is equal to the width of the first metal layer 2, ensuring that the buffer layer can be in full contact with the bottom surface of the electrode structure, thereby improving the adhesion between the entire bottom surface of the electrode structure and the intermediate substrate 1.

[0258] Or, in another case in the fourth embodiment,

[0259] S102: forming a buffer layer on the first surface of the intermediate substrate 1, and patterning the buffer layer to form a buffer pattern. Specifically, a whole layer of the buffer layer may be formed on the first surface of the intermediate substrate 1, and then the whole layer of the buffer layer may be processed by laser etching, wet etching, or etching paste etching to form a buffer pattern.

[0260] In the case where the buffer pattern has been formed in step S102 , “forming a first metal layer 2 and a second metal layer 3 stacked in sequence on the first surface” in step S200 or S200 ′ is replaced by step Sb′.

[0261] Sb′: forming a first metal layer 2 and a second metal layer 3 on the intermediate substrate 1 after the buffer layer patterning process is completed.

[0262] That is, in this step, the first metal layer 2 and the second metal layer 3 are formed to cover the buffer pattern, so that the buffer layer is first patterned, and then the first metal layer 2 and the second metal layer 3 are formed. In this method, the width of the buffer pattern can be greater than or equal to the width of the first metal layer 2, and can also be less than the width of the first metal layer 2, and after the buffer pattern is formed, the first metal layer and the second metal layer are removed by etching, and when selecting the etching solution, it is not necessary to consider its corrosiveness to the buffer layer, so that the selection range of the etching solution is wider.

[0263] In this embodiment, the width of the buffer pattern formed in step S102 is greater than or equal to the width of the first metal layer 2, and the orthographic projection of the first metal layer 2 on the buffer pattern is located within the boundary of the buffer pattern, so that the bottom of the first metal layer 2 is completely in contact with the buffer pattern, further improving the adhesion between the bottom of the first metal layer 2 and the intermediate substrate 1.

[0264] In terms of materials, the buffer layer may include one or more of metal oxides, metal nitrides, metal fluorides, metal silicides and metals. Among them, metal oxides include AZO, TiO X , Cu 2 O、MgO X 、TaO X , VO X CrO X SnO 2 , B: ZnO (boron-doped zinc oxide), CdO X and MoO X One or more of. Metal nitrides include TiN X and TiO X One or more of Ny. Metal fluorides include MgF 2 , LiF, YF 3and CeF 3 One or more combinations thereof. Metal silicides include TiSi 2 、TaSi 2 、MOSi 2 、CoSi 2 、Ni 2 Si and WSi 2 The metal includes one or more of Ni, Ti, Cr, Cu, W, Mo and Ag. The material of the buffer layer can be selected according to actual needs.

[0265] The buffer layer may be a single-layer structure, or the buffer layer may include multiple sub-buffer layers stacked along the thickness direction of the intermediate substrate 1. Multiple sub-buffer layers can reduce the stress of the entire electrode structure and reduce the warpage. The materials of the multiple sub-buffer layers may be different, and the thickness, refractive index or conductivity of the sub-buffer layers may be the same or different.

[0266] If the thickness of the buffer layer is too thick, the carrier transmission efficiency may be reduced, so the thickness of the buffer layer is 5nm to 300nm; and / or, the thickness of the buffer layer is less than or equal to 10% of the thickness of the first metal layer 22 to ensure the carrier transmission efficiency. Exemplarily, the thickness of the buffer layer is 5nm, 50nm, 100nm, 150nm, 200nm, 250nm or 300nm. Alternatively, the thickness of the buffer layer is 10%, 9%, 8%, 7% or 6% of the thickness of the first metal layer 22, etc.

[0267] Embodiment five:

[0268] The fifth embodiment of the present application is different from the third embodiment and the fourth embodiment in that, in the method for manufacturing the solar cell, a step S103 is added after step S100 and before step S200 , or after step S100 ′ and before step S200 ′.

[0269] In one case of the fifth embodiment, S103: a transparent conductive layer 6 and a buffer layer are sequentially formed on the first surface of the intermediate substrate 1, and the transparent conductive layer 6 is closer to the intermediate substrate 1 than the buffer layer. While the buffer layer is used to improve the adhesion between the electrode structure and the intermediate substrate 1, the transparent conductive layer 6 is used to timely guide the collected carriers to reduce the carrier recombination rate.

[0270] In the case that only the entire transparent conductive layer 6 and the buffer layer are formed in step S103, and the transparent conductive layer 6 and the buffer layer are not patterned, step S400 or step S300' includes: cleaning the intermediate substrate 1 with a corrosive solution, and removing the second metal layer 3 located in the isolation region 4 and the first metal layer 2, the buffer layer and the transparent conductive layer 6 thereunder by etching with the corrosive solution, and forming the electrode structure with the first metal layer 2 and the second metal layer 3 in the remaining electrode region 5, forming the transparent conductive pattern with the remaining transparent conductive layer 6 in the remaining electrode region 5, and forming the buffer pattern with the remaining buffer layer in the remaining electrode region 5. In this configuration, in this step, the corrosive solution etches and removes the first metal layer 2, the second metal layer 3, the transparent conductive layer 6 and the buffer layer in the isolation region 4 together, that is, in this step, the first metal layer 2, the second metal layer 3, the transparent conductive layer 6 and the buffer layer are patterned together, which simplifies the processing technology and improves the processing efficiency.

[0271] Alternatively, in another case in the fifth embodiment, S103: a transparent conductive layer 6 and a buffer layer are formed on the first surface of the intermediate substrate 1, and the transparent conductive layer 6 and the buffer layer are processed to form a transparent conductive pattern and a buffer pattern respectively. Here, the transparent conductive layer 6 and the buffer layer can be patterned at the same time, that is, the entire transparent conductive layer 6 and the buffer layer can be formed in sequence on the first surface of the intermediate substrate 1 first, and then the entire transparent conductive layer 6 and the buffer layer can be patterned by laser etching, wet etching or etching paste etching to form a transparent conductive pattern and a buffer pattern respectively; the transparent conductive layer 6 and the buffer layer can also be patterned separately, that is, the transparent conductive layer 6 is formed first, and then the transparent conductive layer 6 is patterned to form a transparent conductive pattern, and then a buffer layer is formed on the transparent conductive pattern, and then the buffer layer is patterned to form a buffer pattern.

[0272] In the case where the transparent conductive pattern and the buffer pattern have been formed in step S103, the step S200 or S200' of "forming a first metal layer 2 and a second metal layer 3 stacked in sequence on the first surface" includes: forming the first metal layer 2 and the second metal layer 3 on the intermediate substrate 1 on which the transparent conductive pattern and the buffer pattern are formed. That is, in this step, the transparent conductive layer 6 and the buffer layer are patterned first, and then the first metal layer 2 and the second metal layer 3 are formed.

[0273] Alternatively, in another case in the fifth embodiment, S103: forming a transparent conductive layer 6 on the first surface of the intermediate substrate 1, and patterning the transparent conductive layer 6 to form a transparent conductive pattern. Specifically, a whole layer of transparent conductive layer 6 can be formed on the first surface of the intermediate substrate 1, and then the whole layer of transparent conductive layer 6 can be patterned by laser etching, wet etching or etching paste etching to form a transparent conductive pattern.

[0274] In the case where the transparent conductive pattern has been formed in step S103, the step of "forming a first metal layer 2 and a second metal layer 3 stacked in sequence on the first surface" in step S200 or S200' includes: forming a buffer layer, a first metal layer 2 and a second metal layer 3 in sequence on the intermediate substrate 1 on which the transparent conductive pattern is formed. That is, in this step, the transparent conductive layer 6 is first patterned, and then the buffer layer, the first metal layer 2 and the second metal layer 3 are formed, and the buffer layer, the first metal layer 2 and the second metal layer 3 are patterned together using an etching solution.

[0275] As for the relationship between the width of the buffer pattern and the transparent conductive pattern and the width of the first metal layer 2 , reference may be made to the above-mentioned third and fourth embodiments, which will not be described in detail herein.

[0276] In this solution, when the solar cell further includes a buffer layer, the width of the transparent conductive pattern may be greater than or equal to the width of the buffer pattern, wherein the width of the buffer pattern may refer to the average width or the maximum width of the buffer pattern.

[0277] Embodiment six:

[0278] The method for manufacturing a solar cell provided in the sixth embodiment of the present application is based on the first to fifth embodiments, and a step S000 is added before the step S100 or S100'.

[0279] S000: forming a dielectric layer 7 on the first surface of the intermediate substrate 1; and opening holes in the dielectric layer 7 located in the electrode region 5. Fig. 9 As shown, a whole dielectric layer 7 can be formed on the first surface of the intermediate substrate 1, and then a laser process is used to open holes in the dielectric layer 7 located in the electrode region 5, and a through hole 7a located opposite to the electrode region 5 is formed on the dielectric layer 7, so that the electrode structure penetrates the dielectric layer 7 and contacts the carrier transport layer below the dielectric layer 7. Figure 10-11 As shown, the subsequent steps in this embodiment are the same as those in Embodiment 1 or Embodiment 2, and will not be repeated here.

[0280] The dielectric layer 7 may include a passivation layer and / or an anti-reflection layer. The passivation layer can protect the surface of the cell and prevent water vapor or oxygen from penetrating into the interior of the cell, thereby avoiding the performance degradation of the cell due to oxidation or hydrolysis; in addition, the provision of the passivation layer can also reduce the surface recombination rate of the cell, thereby improving the photoelectric conversion efficiency of the cell. The anti-reflection layer can reduce the loss of reflected light, improve the light absorption rate and photovoltaic power generation efficiency.

[0281] In the sixth embodiment, the electrode structure is recessed at the opening. During the packaging process, more packaging material is stored at the opening, which is more conducive to the adhesion between the electrode structure and the packaging material at the opening.

[0282] In some examples, the roughness of the electrode structure at the opening is greater than the roughness of the electrode structure at other locations. In this technical solution, the roughness of the electrode structure at the opening is greater, and during the packaging process, the contact area between the electrode structure at the opening and the packaging material can be increased, and the adhesion between the electrode structure at the opening and the packaging material can be improved, thereby improving the firmness of the electrode structure packaging.

[0283] In addition, at the opening, the first metal layer 2 includes a hole, and the hole can be located near the boundary of the opening or inside the opening, that is, the first metal layer 2 is missing at the hole position. In this technical solution, the hole included in the first metal layer 2 can release stress, preventing problems such as loose welding and warping of the battery cell caused by stress release of the electrode structure when welding the electrode structure to the interconnection part, while saving the raw materials for forming the first metal layer.

[0284] The above is an introduction to Embodiment 1 to Embodiment 6. The following content is applicable to Embodiment 1 to Embodiment 6 and other embodiments.

[0285] In some embodiments, the intermediate substrate 1 includes a semiconductor substrate and a doped semiconductor layer arranged on the semiconductor substrate; the orthographic projection of the electrode structure on the intermediate substrate 1 is located within the orthographic projection of the doped semiconductor layer on the intermediate substrate 1, thereby preventing the electrode structure from exceeding the boundary of the doped semiconductor layer and causing leakage.

[0286] Among them, the material of the semiconductor substrate can be selected from materials such as silicon (Si) or germanium (Ge) or materials such as gallium arsenide (GaAs). Obviously, in terms of conductivity type, the semiconductor substrate can be an intrinsic conductive substrate, an n-type conductive substrate or a p-type conductive substrate. Optionally, the semiconductor substrate is a p-type conductive substrate or an n-type conductive substrate. Compared with the intrinsic conductive substrate, the p-type conductive substrate or the n-type conductive substrate has better conductivity, so that the final solar cell has a lower body resistivity, thereby improving the efficiency of the solar cell.

[0287] The above-mentioned doped semiconductor layer may include a first doped semiconductor layer and a second doped semiconductor layer, and the first doped semiconductor layer and the second doped semiconductor layer have opposite conductivity types, so as to collect and guide out electrons and holes respectively, so as to form photocurrent. The materials of the first doped semiconductor layer and the second doped semiconductor layer may be silicon (Si), germanium (Ge), silicon carbide (SiCx) or gallium arsenide (GaAs), etc. The first doped semiconductor layer may be additionally formed on the semiconductor substrate by deposition technology, or may be formed in the semiconductor substrate by diffusion, ion implantation, etc.

[0288] In terms of conductivity type, the first doped semiconductor layer may be an n-type doped layer, and the second doped semiconductor layer may be a p-type doped layer; or, the first doped semiconductor layer may be a p-type doped layer, and the second doped semiconductor layer may be an n-type doped layer.

[0289] In an embodiment including the step of scanning the isolation region 4 with a laser to modify the second metal layer 3 located in the isolation region 4, after sequentially forming the first metal layer 2 and the second metal layer 3 stacked on the first surface, and before scanning the isolation region 4 with a laser, Fig.13 , Fig.16 and Fig.19 As shown, the manufacturing method of the solar cell further includes the step of: forming a protective layer 8 on the side of the second metal layer 3 away from the intermediate substrate 1. Specifically, the formed protective layer 8 is located on the side of the second metal layer 3 away from the first metal layer 2, and the first metal layer 2, the second metal layer 3 and the protective layer 8 are stacked in sequence along the direction away from the intermediate substrate 1.

[0290] like Fig.14 , 17 and Fig. 20 As shown, after the protective layer 8 is formed, the protective layer 8 of the isolation region 4 can be removed during the laser scanning of the isolation region 4. Specifically, the use of laser scanning to modify the second metal layer 3 located in the isolation region 4 includes: using laser scanning to remove the protective layer 8 of the isolation region 4, and modifying the second metal layer 3 located in the isolation region 4. In this step, the protective layer 8 of the isolation region 4 can be removed during the laser scanning of the isolation region 4, and the second metal layer 3 of the isolation region 4 can be modified. Alternatively, the protective layer 8 of the isolation region 4 can be removed first during the laser scanning of the isolation region 4, and then the second metal layer 3 located in the isolation region 4 can be modified. By adopting this method, the removal of the protective layer 8 of the isolation region 4 and the modification of the second metal layer 3 in the isolation region 4 can be achieved in the same step, which simplifies the operation and improves the processing efficiency.

[0291] Alternatively, after forming the protective layer 8, the protective layer 8 of the isolation region 4 may be removed first and then the laser may be used to scan the isolation region 4. Specifically, the protective layer 8 of the isolation region 4 may be removed by wet etching, laser etching, or etching paste, so as to prevent the protective layer 8 of the isolation region 4 from affecting the modification of the second metal layer 3 in the isolation region 4.

[0292] In an embodiment that does not include the step of using laser scanning to modify the second metal layer 3 located in the isolation region 4, after the first metal layer 2 and the second metal layer 3 are sequentially formed on the first surface, and before the intermediate substrate 1 is cleaned with an etching solution, the method for manufacturing a solar cell further includes the steps of forming a protective layer 8 on the side of the second metal layer 3 away from the intermediate substrate 1, and removing the protective layer 8 of the isolation region 4. In this technical solution, the protective layer 8 of the isolation region 4 can be removed by laser etching or etching paste. It can be understood that the purpose of using laser etching in this step is only to remove the protective layer 8 of the isolation region 4, and the second metal layer 3 of the isolation region 4 is not modified.

[0293] Using the above technical solution, such as Fig.15 , Fig.18 and Fig.21 As shown, the protective layer 8 of the electrode area 5 is retained. In the process of using a corrosive liquid to clean the intermediate substrate 1 after laser scanning, the metal layer of the electrode area 5 is covered by the protective layer 8. Therefore, only the metal layer of the isolation area 4 contacts and reacts with the corrosive liquid, thereby completely removing the first metal layer 2 and the second metal layer 3 in the isolation area 4. In addition, the metal layer of the electrode area 5 is not prone to defects, such as holes and impurities, under the protection of the protective layer 8, thereby preventing the corrosive liquid from reacting with the first metal layer 2 through the above defects, thereby damaging the electrode structure.

[0294] In some embodiments, the protective layer 8 can be formed by a dry process. Among them, the dry process includes LPCVD (Low Pressure Chemical Vapor Deposition), PECVD (Plasma Enhanced Chemical Vapor Deposition), PVD (Physical Vapor Deposition), PEALD (Plasma Enhanced Atomic Layer Deposition) and other methods. By adopting the above-mentioned methods, it is only necessary to form a protective layer 8 with a thickness of nanometers to achieve a better protection effect on the metal layer of the electrode area 5. In addition, when the protective layer 8 is formed by a PVD process, for example, the protective layer 8 is formed by evaporation or sputtering, the first metal layer 2, the second metal layer 3 and the protective layer 8 can be formed in sequence by using PVD equipment to reduce the number of equipment required for manufacturing the film layer and reduce the equipment cost.

[0295] In other embodiments, the protective layer 8 can be formed by a wet process. The wet process includes spraying, spin coating and / or dipping. Specifically, a solution of the material of the protective layer 8 is first prepared, and then an intermediate of the protective layer 8 is formed on the surface of the second metal layer 3 by spraying, spin coating and / or dipping, and then the intermediate substrate 1 is dried to finally form the protective layer 8 on the surface of the second metal layer 3 away from the intermediate substrate 1. With this technical solution, the process is simple, no high-temperature heating is required, energy is saved and the production efficiency is high.

[0296] In terms of materials, the material of the protective layer 8 may include at least one of polyvinylidene difluoride (PVDF), polypropylene (PP), polyethylene (PE), polystyrene (PS), ether-ether-ketone (PEEK), and polytetrafluoroethylene (PTFE). The protective layer 8 formed by the above materials has higher density and better protection effect.

[0297] Alternatively, the material of the protective layer 8 may also include a water-insoluble or alkali-resistant polymer material, for example, the material of the protective layer 8 includes at least one of chitosan, silicone oil, polyvinylidene fluoride, stearic acid, paraffin, ink, water-insoluble cellulose derivatives, and fluororesin. The protective layer 8 is made of the above materials, the process is simple, high-temperature heating is not required, energy is saved, and the production efficiency is high.

[0298] In terms of thickness, if the thickness of the protective layer 8 is too large, it will lead to a waste of raw materials. If the thickness of the protective layer 8 is too small, it will lead to a poor protection effect on the metal layer of the electrode region 5, and the surface of the metal layer of the electrode region 5 is prone to defects during the corrosion process of the corrosive liquid. In view of the above situation, the thickness of the protective layer 8 in this solution is 10nm to 3000nm, so as to ensure a good protection effect on the metal layer of the electrode region 5 while avoiding waste of raw materials. Exemplarily, the thickness of the protective layer 8 can be 10nm, 100nm, 300nm, 500nm, 800nm, 1000nm, 1300nm, 1500nm, 1800nm, 2000nm, 2300nm, 2500nm, 2800nm ​​or 3000nm.

[0299] Specifically, the thickness of the protective layer 8 can be set according to the material of the protective layer 8. In some examples, when the material of the protective layer 8 includes at least one of polyvinylidene fluoride, polypropylene, polyethylene, polystyrene, polyetheretherketone, and polytetrafluoroethylene, the thickness of the protective layer 8 is 10nm to 500nm. At this time, the transparency of the protective layer 8 is high, and the presence of the protective layer 8 will not reduce the optical performance of the solar cell, thereby ensuring the photoelectric conversion efficiency of the solar cell. For example, the thickness of the protective layer 8 is 10nm, 50nm, 80nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm or 500nm.

[0300] In other examples, when the material of the protective layer 8 includes at least one of chitosan, silicone oil, polyvinylidene fluoride, stearic acid, paraffin, ink, non-water-soluble cellulose derivatives, and fluororesin, the thickness of the protective layer 8 is 0.5μm to 3μm, for example, the thickness of the protective layer 8 is 0.5μm, 0.8μm, 1μm, 1.2μm, 1.5μm, 1.8μm, 2μm, 2.2μm, 2.5μm, 2.8μm or 3μm, etc.

[0301] In other embodiments, after the intermediate substrate 1 after laser scanning processing is cleaned with a corrosive liquid, the above manufacturing method further includes: removing the protective layer 8. For example, when the protective layer 8 is formed of a water-insoluble or alkali-resistant polymer material, the thickness of the protective layer 8 is generally in the micron level, and the thickness is relatively thick. In the process of welding the conductive part (welding strip or main grid) with the formed electrode structure, the protective layer 8 will block the direct contact between the welding material and the electrode structure. Therefore, after the electrode structure is formed, the protective layer 8 in the metal area needs to be removed to prevent the protective layer 8 from affecting the welding effect between the electrode structure and the conductive part (welding strip or main grid). Specifically, the intermediate substrate 1 can be cleaned with a solvent that can dissolve the protective layer 8 to remove the protective layer 8.

[0302] Of course, after the intermediate substrate 1 after laser scanning is cleaned with the corrosive liquid, the protective layer 8 may not be removed. For example, when the protective layer 8 is prepared by at least one of polyvinylidene fluoride, polypropylene, polyethylene, polystyrene, polyetheretherketone, and polytetrafluoroethylene, due to the high preparation temperature, the surface wettability of the protective layer 8 is strong. In the process of welding the conductive member (welding strip or main grid) with the formed electrode structure, the welding temperature is higher than the melting point of the protective layer 8. The protective layer 8 can be directly melted during the welding process to achieve direct contact between the conductive member (welding strip or main grid) and the electrode structure. Therefore, the protective layer 8 is not removed, and the welding effect of the conductive member (welding strip or main grid) and the electrode structure is not affected. In addition, in this technical solution, the mutual diffusion effect between the protective layer 8 and the welding material is more obvious, and the composite material formed by the protective layer 8 and the welding material is thicker, which can protect the electrode structure, and the protective layer 8 in the non-welding area can also prevent the electrode structure from being eroded by oxygen and / or water. At the same time, the protective layer 8 has insulation, which can reduce the risk of leakage of the electrode structure.

[0303] In practical applications, according to the difference between the material of the protective layer 8 and the surface tension and surface energy of the metal layer, the density of the protective layer 8 formed on the second metal layer 3 may not reach the most ideal uniform density state, and there is an island-like structure. In particular, for the metal layer prepared on the velvet surface, its structure changes with the ups and downs of the velvet surface, so the protective layer 8 formed on the metal layer on the velvet surface is prone to reduce the density due to the ups and downs. Therefore, the corrosion liquid can include a corrosion inhibitor to fill the defects of the protective layer 8 to improve the density of the protective layer 8; in addition, since the corrosion inhibitor usually fills nano-scale defects, and the holes on the metal layer of the isolation area 4 scanned by the laser are at the micron level, it is difficult for the corrosion inhibitor to fill them, thereby ensuring that the addition of the corrosion inhibitor will not affect the corrosion of the metal layer of the isolation area 4 by the corrosion liquid. Among them, the corrosion inhibitor can include one or more sodium or potassium salts of silicates, phosphates, molybdates, and phytates.

[0304] In some embodiments, Fig. 22 and Fig.23As shown, the intermediate substrate includes a semiconductor substrate 10 and a first doped semiconductor layer 30, and the first doped semiconductor layer 30 is disposed on the first surface. The formed electrode structure includes a first electrode structure 50, and the first electrode structure 50 is located on the side of the first doped semiconductor layer 30 away from the semiconductor substrate 10; along the width direction of the first electrode structure 50, the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is greater than or equal to 0.1, and less than or equal to 1.1. That is, along the direction perpendicular to the extension of the first doped semiconductor layer 30, the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is in the range of 0.1 to 1.1. By adopting the above technical solution, the light irradiated from the second surface to the semiconductor substrate 10 will be reflected back to the semiconductor substrate 10 by the first electrode structure 50 when passing through the semiconductor substrate 10 to irradiate the first electrode structure 50, so that the semiconductor substrate 10 absorbs the light for the second time. In this solution, since the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is greater than or equal to 0.1 and less than or equal to 1.1, the first electrode structure 50 covers a larger area of ​​the first doped semiconductor layer 30. Therefore, compared with the case where the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is less than 0.1, the reflectivity of the first electrode structure 50 in the present application that reflects the light passing through the semiconductor substrate 10 back to the semiconductor substrate 10 is greater, thereby improving the absorption utilization rate of the solar cell for the light incident from the second surface and improving the photoelectric conversion efficiency. Moreover, since the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 in the present embodiment is greater than or equal to 0.1 and less than or equal to 1.1, when the width of the first doped semiconductor layer 30 is constant, the width of the first electrode structure 50 in the present embodiment accounts for a large proportion, that is, the width of the first electrode structure 50 is large. On the premise that the thickness of the first electrode structure 50 remains unchanged, the wider the first electrode structure 50, the lower the transmission resistance and the lower the series resistance, thereby improving the fill factor FF to improve the efficiency of the solar cell; or, on the premise that the resistance of the first electrode structure 50 remains unchanged, the thickness of the first electrode structure 50 can be reduced due to the increase in the width of the first electrode structure 50, and the reduction in the thickness of the first electrode structure 50 is conducive to improving the manufacturing efficiency of the first electrode structure 50.

[0305] Exemplarily, the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 or 1.1.

[0306] In the case where the first surface is the backlight surface, the light irradiated from the second surface to the semiconductor substrate 10 will pass through the semiconductor substrate 10 and return to the environment, reducing the absorption and utilization rate of the light. Therefore, in some embodiments, the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is 0.6-1.1, so that the first electrode structure 50 covers a larger area of ​​the first doped semiconductor layer 30, and the light passing through the semiconductor substrate 10 will be reflected back to the semiconductor substrate 10 by the first electrode structure 50 when irradiating to the first electrode structure 50, so that the semiconductor substrate 10 absorbs the light twice, thereby further improving the absorption and utilization rate of the solar cell to the light and improving the photoelectric conversion efficiency. Exemplarily, the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is 0.65, 0.75, 0.85, 0.88, 0.92, 0.95, 0.98, 1.02 or 1.08.

[0307] In some embodiments, the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is 0.1-0.2, so that the first electrode structure 50 covers a smaller area of ​​the first doped semiconductor layer 30, which further saves the raw materials of the first electrode structure 50; in addition, more light can be incident from the first surface to the semiconductor substrate. Exemplarily, the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is 0.15, 0.25, 0.35, 0.45, 0.55, 0.65, 0.75, 0.85 or 0.95.

[0308] In some embodiments, when the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is less than or equal to 1, the orthographic projection of the first electrode structure 50 on the first doped semiconductor layer 30 is located within the boundary of the first doped semiconductor layer 30, such as Fig. 22As shown, along the width direction of the first electrode structure 50, the distance D1 between the edge of the first electrode structure 50 and the edge of the first doped semiconductor layer 30 on the same side is 0-40 μm. That is, the width of the first electrode structure 50 is less than or equal to the width of the first doped semiconductor layer 30, and along the width direction of the first electrode structure 50, at least one side edge of the first electrode structure 50 is between the two side edges of the first doped semiconductor layer 30. In addition, along the width direction of the first electrode structure 50, the distance D1 between the edge of the first electrode structure 50 on the same side and the edge of the first doped semiconductor layer 30 is set within a reasonable range of 0-40 μm, which can ensure that the width of the first electrode structure 50 is relatively wide while preventing the width of the first electrode structure 50 from being too wide and contacting another doped semiconductor layer of the opposite conductivity type, resulting in leakage. Among them, the edge of the first electrode structure 50 and / or the edge of the first doped semiconductor layer 30 can extend along a straight line, a regular curve or an irregular curve, for example, the edge of the first electrode structure 50 and / or the edge of the first doped semiconductor layer 30 extends along a wavy line.

[0309] Exemplarily, the distance D1 between the edge of the first electrode structure 50 and the edge of the first doped semiconductor layer 30 on the same side is 0, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm or 40 μm. Optionally, D1 is 0-20 μm.

[0310] In some embodiments, Fig.24 As shown, along the width direction of the first electrode structure 50, the absolute value of the difference between the distance between any two points on the edge of the first electrode structure 50 and the edge of the first doped semiconductor layer 30 on the same side is ΔD1, 0≤ΔD1≤40μm. Exemplarily, take any two points A and B on the same side of the edge of the first electrode structure 50, along the width direction of the first electrode structure 50, the distance between point A and the edge of the first doped semiconductor layer 30 on the same side is the distance D between A-A'. A The distance between point B and the edge of the first doped semiconductor layer 30 on the same side is the distance D between point B-B'. B , D A With D B The absolute value of the difference is ΔD1, that is, ΔD1 = |D A -D B |. In this technical solution, ΔD1 is set within a reasonable range of 0 to 40 μm to ensure that the distances between any two points on the edge of the first electrode structure 50 and the edge of the first doped semiconductor layer 30 are close, so that the shape of the edge of the first electrode structure 50 is similar to that of the edge of the first doped semiconductor layer 30. Based on this, the first electrode structure 50 covers a larger area of ​​the first doped semiconductor layer 30, thereby further improving the absorption and utilization rate of the solar cell for light and improving the photoelectric conversion efficiency.

[0311] Illustratively, ΔD1 may be 0, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, or 40 μm.

[0312] like Fig. 22 As shown, in the case where the solar cell further includes a second doped semiconductor layer 70 and a second electrode structure 60, the formed electrode structure further includes a second electrode structure, and the second electrode structure 60 is arranged on a side of the second doped semiconductor layer 70 away from the semiconductor substrate 10, so as to use the second electrode structure 60 to conduct the carriers collected by the second doped semiconductor layer 70. The solar cell can be a back contact cell or a bifacial cell.

[0313] In the case where the solar cell is a back-contact cell, in some embodiments, along the width direction of the second electrode structure 60 , the ratio of the width of the second electrode structure 60 to the width of the second doped semiconductor layer 70 is greater than or equal to 0.1 and less than or equal to 1.1. In the case where the second doped semiconductor layer 70 is arranged on the first surface, the above technical solution is adopted, and the light irradiated from the second surface to the semiconductor substrate 10 will be reflected back to the semiconductor substrate 10 by the second electrode structure 60 when passing through the semiconductor substrate 10 to irradiate the second electrode structure 60, so that the semiconductor substrate 10 absorbs the light again. In this solution, since the ratio of the width of the second electrode structure 60 to the width of the second doped semiconductor layer 70 is greater than or equal to 0.1 and less than or equal to 1.1, the area of ​​the second doped semiconductor layer 70 covered by the second electrode structure 60 is larger. Therefore, compared with the case where the ratio of the width of the second electrode structure 60 to the width of the second doped semiconductor layer 70 is less than 0.1, the reflectivity of the second electrode structure 60 in the present application that reflects the light passing through the semiconductor substrate 10 back to the semiconductor substrate 10 is greater, thereby improving the absorption utilization rate of the solar cell for the light incident from the second surface and improving the photoelectric conversion efficiency. Moreover, since the ratio of the width of the second electrode structure 60 to the width of the second doped semiconductor layer 70 in the present application is greater than or equal to 0.1 and less than or equal to 1.1, when the width of the second doped semiconductor layer 70 is constant, the width of the second electrode structure 60 in the present application accounts for a larger proportion, that is, the width of the second battery layer is larger, and under the premise that the thickness of the second electrode structure 60 remains unchanged, the wider the second electrode structure 60, the lower the transmission resistance, and the lower the series resistance, thereby improving the fill factor FF to improve the efficiency of the solar cell; or, under the premise that the resistance of the second electrode structure 60 remains unchanged, the thickness of the second electrode structure 60 can be reduced due to the increase in the width of the second electrode structure 60, and the reduction in the thickness of the second electrode structure 60 is conducive to improving the manufacturing efficiency of the second electrode structure 60.

[0314] When the second doped semiconductor layer 70 is disposed on the second surface, the second doped semiconductor layer 70 and the first doped semiconductor layer 30 are disposed on the first surface and the second surface of the semiconductor substrate 10 respectively, which can reduce leakage risk and current loss.

[0315] Exemplarily, the ratio of the width of the second electrode structure 60 to the width of the second doped semiconductor layer 70 is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1 or 1.1. Optionally, the ratio of the width of the second electrode structure 60 to the width of the second doped semiconductor layer 70 is 0.1-0.2 or 0.6-1.1, and the effect can refer to the beneficial effect corresponding to the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 in this range.

[0316] In some embodiments, when the ratio of the width of the second electrode structure 60 to the width of the second doped semiconductor layer 70 is less than or equal to 1, the projection of the second electrode structure 60 on the second doped semiconductor layer 70 is located within the boundary of the second doped semiconductor layer 70. Fig. 22 As shown, along the width direction of the second electrode structure 60, the distance D2 between the edge of the second electrode structure 60 and the edge of the second doped semiconductor layer 70 on the same side is 0-40 μm. That is, the width of the second electrode structure 60 is less than or equal to the width of the second doped semiconductor layer 70, and along the width direction of the second electrode structure 60, at least one side edge of the second electrode structure 60 is between the two side edges of the second doped semiconductor layer 70. In addition, along the width direction of the second electrode structure 60, the distance D2 between the edge of the second electrode structure 60 on the same side and the edge of the second doped semiconductor layer 70 is set within a reasonable range of 0-40 μm, which can ensure that the width of the second electrode structure 60 is relatively wide while preventing the width of the second electrode structure 60 from being too wide and contacting another doped semiconductor layer of the opposite conductivity type, resulting in leakage. Among them, the edge of the second electrode structure 60 and / or the edge of the second doped semiconductor layer 70 can extend along a straight line, a regular curve or an irregular curve, for example, the edge of the second electrode structure 60 and / or the edge of the second doped semiconductor layer 70 extends along a wavy line.

[0317] Exemplarily, the distance D2 between the edge of the second electrode structure 60 and the edge of the second doped semiconductor layer 70 on the same side is 0, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm or 40 μm. Optionally, D2 is 0-20 μm.

[0318] In some embodiments, along the width direction of the second electrode structure 60, the absolute value of the difference between the distance between any two points on the edge of the second electrode structure 60 and the edge of the second doped semiconductor layer 70 on the same side is ΔD2, 0≤ΔD2≤40μm. Exemplarily, take any two points C and E on the same side of the edge of the second electrode structure 60, along the width direction of the second electrode structure 60, the distance between point C and the edge of the second doped semiconductor layer 70 on the same side is the distance D between C-C'. C The distance between point E and the edge of the second doped semiconductor layer 70 on the same side is the distance D between point E-E'. E , D C With D E The absolute value of the difference is ΔD2, that is, ΔD2 = |D C -D E |. In this technical solution, ΔD2 is set within a reasonable range of 0 to 40 μm to ensure that the distances between any two points on the edge of the second electrode structure 60 and the edge of the second doped semiconductor layer 70 are close, so that the shape of the edge of the second electrode structure 60 is similar to that of the edge of the second doped semiconductor layer 70. Based on this, the second electrode structure 60 covers a larger area of ​​the second doped semiconductor layer 70, thereby further improving the absorption and utilization rate of the solar cell for light and improving the photoelectric conversion efficiency.

[0319] Illustratively, ΔD2 may be 0, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, or 40 μm.

[0320] In some embodiments, Fig.25 As shown, the ratio of the width of the first electrode structure 50 to the width of the first doped semiconductor layer 30 is greater than 1 and less than or equal to 1.1, and the orthographic projection of the first doped semiconductor layer 30 on the first surface is located inside the orthographic projection of the first electrode structure 50 on the first surface, that is, the edge of the first doped semiconductor layer 30 is located inside the edge of the first electrode structure 50. The ratio of the width of the second electrode structure 60 to the width of the second doped semiconductor layer 70 is greater than 1 and less than or equal to 1.1, and the orthographic projection of the second doped semiconductor layer 70 on the first surface is located inside the orthographic projection of the second electrode structure 60 on the first surface, that is, the edge of the second doped semiconductor layer 70 is located inside the edge of the second electrode structure 60. With this technical solution, the first electrode structure 50 can completely cover the first doped semiconductor layer 30, the second electrode structure 60 can completely cover the second doped semiconductor layer 70, and the first electrode structure 50 and / or the second electrode structure 60 will extend into the isolation region, and thus can also reflect the light in the isolation region back to the semiconductor substrate 10, further improving the absorption and utilization rate of the solar cell for light.

[0321] In another embodiment, the conductivity type of the second doped semiconductor layer 70 and the second electrode structure 60 is opposite to that of the semiconductor substrate 10, and along the width direction of the first doped semiconductor layer 30 or the second doped semiconductor layer 70, the distance that the edge of the second electrode structure 60 exceeds the edge of the second doped semiconductor layer 70 on the same side is greater than the distance that the edge of the first electrode structure 50 exceeds the edge of the first doped semiconductor layer 30 on the same side. In this way, the width of the second electrode structure 60 is made wider, wherein the conductivity type of the second electrode structure 60 is opposite to that of the semiconductor substrate 10, so the second electrode structure 60 is used to extract minority carriers in the semiconductor substrate 10, and the larger the width of the second electrode structure 60, the more conducive it is to extract minority carriers, and the more minority carriers are extracted, the more minority carrier collection efficiency is improved, and the more conducive it is to reduce recombination, thereby facilitating the improvement of the efficiency of solar cells.

[0322] Exemplarily, along the width direction of the first doped semiconductor layer 30, the edge of the first electrode structure 50 exceeds the edge of the first doped semiconductor layer 30 on the same side by a distance of 0 to 10 μm. Along the width direction of the second doped semiconductor layer 70, the edge of the second electrode structure 60 exceeds the edge of the second doped semiconductor layer 70 on the same side by a distance of 0 to 10 μm. Considering that the greater the distance that the edge of the first electrode structure 50 exceeds the edge of the first doped semiconductor layer 30 on the same side and the distance that the edge of the second electrode structure 60 exceeds the edge of the second doped semiconductor layer 70 on the same side, the closer the edge of the first electrode structure 50 is to the second doped semiconductor layer 70, and the closer the edge of the second electrode structure 60 is to the first doped semiconductor layer 30, which is prone to leakage. Therefore, this technical solution is adopted to ensure that a safe distance is reserved between the edge of the second electrode structure 60 and the first doped semiconductor layer 30 and between the edge of the first electrode structure 50 and the second doped semiconductor layer 70, further reducing the risk of leakage. Optionally, the distance that the edge of the first electrode structure 50 exceeds the edge of the first doped semiconductor layer 30 on the same side is 0 to 6 μm.

[0323] For example, the edge of the first electrode structure 50 exceeds the edge of the first doped semiconductor layer 30 on the same side by a distance of 0, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm. The edge of the second electrode structure 60 exceeds the edge of the second doped semiconductor layer 70 on the same side by a distance of 0, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0324] In some examples, the solar cell is a back contact solar cell, in which case, the electrode region 5 includes a first electrode region 5 and a second electrode region 5; the isolation region 4 is disposed between the first electrode region 5 and the second electrode region 5. The first doped semiconductor layer is at least disposed in the first electrode region 5, and the second doped semiconductor layer is at least disposed in the second electrode region 5. Step S400 or step S300' comprises: cleaning the intermediate substrate 1 with an etching solution, etching and removing the second metal layer 3 and the first metal layer 2 thereunder located in the isolation region 4 by the etching solution, and the remaining first metal layer 2 and the second metal layer 3 in the first electrode region 5 form a first electrode structure, and the remaining first metal layer 2 and the second metal layer 3 in the second electrode region 5 form a second electrode structure. The first electrode structure formed in the first electrode region 5 is electrically connected to the first doped semiconductor layer for conducting the carriers collected by the first doped semiconductor layer; the second electrode structure formed in the second electrode region 5 is electrically connected to the second doped semiconductor layer for conducting the carriers collected by the second doped semiconductor layer.

[0325] Among them, a first interface layer 40 can also be provided on the side of the first doped semiconductor layer close to the semiconductor substrate, and a second interface layer 80 can also be provided on the side of the second doped semiconductor layer close to the semiconductor substrate. In some examples, the first doped semiconductor layer includes one or more of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon; the second doped semiconductor layer includes one or more of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The material of the first interface layer 40 can be determined according to the material of the first doped semiconductor layer. For example: in the case where the first doped semiconductor layer includes a doped polycrystalline silicon layer, the first interface layer 40 is a tunneling oxide layer; in this way, the first doped semiconductor layer and the first interface layer 40 form a tunneling oxide layer passivation contact, and the tunneling oxide layer passivation technology can form a tunneling film between the first electrode and the semiconductor substrate, isolate the first electrode from the semiconductor substrate, reduce the contact recombination loss, and the electron can tunnel through the film without affecting the current transfer, and the passivation can bend the surface energy band, reduce the surface recombination loss of the silicon wafer, and effectively improve the front passivation and metal contact problem. For another example: when the first doped semiconductor layer includes a doped amorphous silicon layer, the first interface layer 40 includes an intrinsic amorphous silicon layer. The material of the second interface layer 80 can be determined according to the material of the second doped semiconductor layer. For example: when the second doped semiconductor layer includes a doped polysilicon layer, the second interface layer 80 is a tunneling oxide layer; for another example: when the second doped semiconductor layer includes a doped amorphous silicon layer, the second interface layer 80 includes an intrinsic amorphous silicon layer.

[0326] In other examples, the solar cell is a bifacial solar cell, in which case the second surface of the intermediate substrate 1 includes an electrode region 5 and an isolation region 4. Here, the method of forming an electrode structure on the first surface and the method of forming an electrode structure on the second surface may be the same or different. In the case where the method of forming an electrode structure on the first surface and the method of forming an electrode structure on the second surface are the same, the method of forming an electrode structure on the second surface may refer to the method of forming an electrode structure on the first surface. In the case where a transparent conductive pattern or a buffer pattern is formed on the second surface, the method of forming a transparent conductive pattern and / or a buffer pattern on the second surface may refer to the method of forming a transparent conductive pattern and / or a buffer pattern on the first surface, which will not be repeated here.

[0327] In some embodiments, in the electrode structure formed by applying the manufacturing method of the solar cell, along the extension direction of the first metal layer 2, the boundary of the first metal layer 2 extends in a wavy shape. It can be understood that the two sides of the first metal layer 2 appear to extend along the wavy line as a whole. The fluctuation amplitude and / or fluctuation frequency of the wavy shape can be adjusted by controlling the process, for example, controlling the spot size of the laser, the overlapping area of ​​the spot, etc. By adopting this technical solution, the overall extension length of the first metal layer 2 can be increased, thereby increasing the transmission path and area of ​​the carriers in the first metal layer 2, which is beneficial to reduce the contact resistance.

[0328] In other examples, in the electrode structure formed by applying the manufacturing method of the solar cell, the width of the first metal layer 2 gradually increases along the direction close to the semiconductor substrate. The width of the lower surface of the first metal layer 2 close to the semiconductor substrate is the largest, and the width of the upper surface of the first metal layer 2 away from the semiconductor substrate is the smallest. In this way, the contact area between the first metal layer 2 and the semiconductor substrate is large, which increases the adhesion between the first metal layer 2 and the semiconductor substrate and helps to reduce the contact resistance. In addition, the side of the first metal layer 2 will not be blocked by the upper surface of the first metal layer 2, so that more light can be irradiated to the side of the first metal layer 2, and then more light can be reflected to the semiconductor substrate, thereby improving the utilization rate of light.

[0329] The thickness of the second metal layer 3 is less than or equal to the thickness of the first metal layer 2 to ensure that the second metal layer 3 is firmly welded to the welding strip or interconnection component while facilitating patterning of the second metal layer 3, for example, making the laser used for laser patterning of the second metal layer 3 more selective.

[0330] Since the energy at the edge of the laser spot is weaker than the energy at the center of the laser spot, if the width of the laser irradiation is smaller than the width of the isolation region 4, the modification effect of the second metal layer 3 at the edge of the isolation region 4 may be affected, and ultimately the second metal layer 3 and the first metal layer 2 at the edge of the isolation region 4 cannot be completely removed or the removal rate is slow, which in turn causes the width of the formed electrode structure to be inconsistent with the preset width of the electrode structure, affecting the width accuracy of the electrode structure. Based on this, in some embodiments, the width of the laser irradiation is made greater than or equal to the width of the isolation region 4 to ensure the modification effect of the second metal layer 3 at the edge of the isolation region 4, thereby ensuring that the second metal layer 3 and the first metal layer 2 at the edge of the isolation region 4 are completely removed or the removal rate of the second metal layer 3 and the first metal layer 2 at the edge of the isolation region 4 is increased.

[0331] In some examples, when the width of laser irradiation is greater than the width of isolation region 4, the difference between the width of laser irradiation and the width of isolation region 4 is 0 to 400um. If the width of laser irradiation is too narrow, the width of the electrode structure formed may be wider, which may easily lead to leakage; if the width of laser irradiation is too wide, the width of the electrode structure formed may be narrower, affecting the transmission efficiency of carriers. In view of the above two situations, in this embodiment, the difference between the width of laser irradiation and the width of isolation region 4 is set within a reasonable range of 0 to 400um to prevent leakage between adjacent electrode structures and improve the transmission efficiency of carriers.

[0332] Exemplarily, the difference between the width of the laser irradiation and the width of the isolation region 4 is 0, 50um, 100um, 150um, 200um, 250um, 300um, 350um or 400um, etc.

[0333] In some embodiments, in the step of scanning the isolation region 4 with laser, an inert gas is blown toward the first surface during the process of scanning the isolation region 4 with laser. The inert gas may include argon, helium, etc. to protect the molten metal and the laser lens barrel.

[0334] In some embodiments, in the step of scanning the isolation region 4 with a laser, the scanning speed of the laser is 2m / s to 50m / s. Specifically, if the scanning speed of the laser is too fast or too slow, it will affect the modification effect of the second metal layer 3 in the isolation region 4. Therefore, in this embodiment, the scanning speed of the laser is set within a reasonable range of 2m / s to 50m / s to ensure the modification effect of the second metal layer 3 in the isolation region 4. Exemplarily, the scanning speed of the laser is 2m / s, 5m / s, 10m / s, 15m / s, 20m / s, 25m / s, 30m / s, 35m / s, 40m / s, 45m / s or 50m / s.

[0335] In some embodiments, along the width direction of the electrode structure, the width of the second metal layer 3 is greater than the width of the surface of the first metal layer 2 away from the intermediate substrate 1, that is, the width of the second metal layer 3 is greater than the width of the upper surface of the first metal layer 2. This arrangement can ensure that there is a larger contact area between the second metal layer 3 of the electrode structure and the welding strip or interconnection during the welding process, thereby improving the welding efficiency. Alternatively, the width of the second metal layer 3 is equal to the width of the surface of the first metal layer 2 away from the intermediate substrate 1, that is, the width of the second metal layer 3 is equal to the width of the upper surface of the first metal layer 2. This arrangement can avoid the second metal layer 3 from blocking the first metal layer 2, avoiding affecting the absorption of light by the first metal layer 2, and the first metal layer 2 reflecting light to the intermediate substrate 1. Of course, the width of the second metal layer 3 can also be less than the width of the surface of the first metal layer 2 away from the intermediate substrate 1, that is, the width of the second metal layer 3 is less than the width of the upper surface of the first metal layer 2, which is not limited here.

[0336] Wherein, in the case where the width of the second metal layer 3 is greater than the width of the surface of the first metal layer 2 away from the intermediate substrate 1, the portion of the second metal layer 3 that exceeds the first metal layer 2 may extend in a direction parallel to the first surface of the intermediate substrate 1, may extend in a direction close to the first surface of the intermediate substrate 1, or may extend in a direction away from the first surface of the intermediate substrate 1. Wherein, the width of the second metal layer 3 may refer to the average width or maximum width of the first metal layer 2; the width of the surface of the first metal layer 2 away from the intermediate substrate 1 may refer to the average width or maximum width of the surface of the first metal layer 2 away from the intermediate substrate 1.

[0337] It should be noted that in the embodiment of the present application, the relationship between the width of the second metal layer 3 in the electrode structure and the width of the surface of the first metal layer 2 away from the intermediate substrate 1, as well as the position setting relationship between the second metal layer 3 and the first metal layer 2, can be any position of the electrode structure that satisfies the relationship described in the specification of the present application, or all positions of the electrode structure can satisfy the relationship described in the specification of the present application. In addition, for different positions of the electrode structure, the size relationship and position setting relationship of the second metal layer 3 and the first metal layer 2 can be the same or different.

[0338] In the case where the width of the second metal layer 3 along the width direction of the electrode structure is greater than the width of the surface of the first metal layer 2 away from the intermediate substrate 1, the difference between the width of the second metal layer 3 in the electrode structure and the width of the surface of the first metal layer 2 away from the intermediate substrate 1 is in the range of 1 μm to 30 μm. That is, at least one side of the second metal layer 3 exceeds the edge of the surface of the first metal layer 2 away from the intermediate substrate 1. Specifically, only one side of the second metal layer 3 may exceed the edge of the upper surface of the first metal layer 2, or both sides of the second metal layer 3 may exceed the edge of the upper surface of the first metal layer 2. On this basis, for any side of the electrode structure along its width direction, the second metal layer 3 may exceed the edge of the upper surface of the first metal layer 2 in the extension direction of the electrode structure in whole or in part. Exemplarily, the difference between the width of the second metal layer 3 in the electrode structure and the width of the surface of the first metal layer 2 away from the intermediate substrate 1 may be in the range of 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm or 30 μm. By adopting this technical solution, the second metal layer 3 exceeds the edge of the upper surface of the first metal layer 2 within a reasonable range, which not only ensures that there is a larger contact area between the second metal layer 3 of the electrode structure and the welding strip or the interconnection part during the welding process, but also avoids the side of the first metal layer 2 being blocked by the second metal layer 3, so that more light can be irradiated to the side of the first metal layer 2.

[0339] Considering that the width of the surface of the first metal layer 2 away from the intermediate substrate 1 is much smaller than the width of the second metal layer 3, the side of the first metal layer 2 will be blocked by the second metal layer 3, affecting the utilization rate of light; if the width of the surface of the first metal layer 2 away from the intermediate substrate 1 is much larger than the width of the second metal layer 3, the width of the second metal layer 3 will be limited when the overall width of the electrode structure remains unchanged, reducing the contact area between the second metal layer 3 and the welding strip or the interconnection member. Therefore, when designing the width of the first metal layer 2 and the second metal layer 3, the width of the surface of the first metal layer 2 away from the intermediate substrate 1 can be 80% to 110% of the width of the second metal layer 3, that is, the width of the upper surface of the first metal layer 2 is 80% to 110% of the width of the second metal layer 3, so as to avoid the side of the first metal layer 2 being blocked by the second metal layer 3, so that more light is irradiated to the side of the first metal layer 2, and then more light is reflected to the intermediate substrate 1, improving the utilization rate of light, and at the same time ensuring that there is a larger contact area between the second metal layer 3 in the electrode structure and the welding strip during the welding process, thereby improving the welding efficiency.

[0340] Exemplarily, the width of the surface of the first metal layer 2 facing away from the intermediate substrate 1 is 80%, 85%, 90%, 95%, 100%, 105% or 110% of the width W2 of the second metal layer 3 .

[0341] In some embodiments, the etching solution includes NaOH, KOH, HCl, H 2SO 4 , HNO 3 , H 3 PO 4 , tetramethylammonium hydroxide and ammonia water. The above-mentioned types of etching solutions have good etching effects and low costs. Specifically, the mass concentration of the etching solution can be 0.1-10%, the cleaning temperature is 10-50°C, and the cleaning time is 30s-1200s. The intermediate substrate 1 can be cleaned by immersion and / or ultrasound. Specifically, the intermediate substrate 1 can be immersed in the etching solution for 200s-600s, or placed in an ultrasonic device containing the etching solution for ultrasonic-assisted cleaning for 30s-200s.

[0342] In some embodiments, during the process of preparing the electrode structure, the first metal layer 2 and the second metal layer 3 can be formed by LPCVD, PECVD, PVD, PEALD, etc., so that the first metal layer 2 and the second metal layer 3 formed in the electrode area 5 have a high density. When the second metal layer 3 is used as a welding layer, it is beneficial to improve the welding effect of the second metal layer 3.

[0343] Specifically, the first metal layer 2 is formed by magnetron sputtering or evaporation; and / or, the second metal layer 3 is formed by magnetron sputtering or evaporation. It is understandable that the first metal layer 2 and the second metal layer 3 can be formed by the same process. For example, the first metal layer 2 and the second metal layer 3 can both be formed by magnetron sputtering or by evaporation; or, the first metal layer 2 and the second metal layer 3 can also be formed by different processes. For example, the first metal layer 2 is formed by magnetron sputtering and the second metal layer 3 is formed by evaporation, or the first metal layer 2 is formed by evaporation and the second metal layer 3 is formed by magnetron sputtering.

[0344] Among them, the first metal layer 2 may include multiple first sub-metal layers stacked along the thickness direction of the intermediate substrate 1. With such a configuration, multiple first sub-metal layers can be processed in sequence to form multiple first sub-metal layers. The materials of the multiple first sub-metal layers can be different, and the thicknesses of the multiple first sub-metal layers can be the same or different. The number of layers, thickness and material of the first sub-metal layer can be set according to actual conditions. Specifically, the first sub-metal layer can be 2 layers, 3 layers, 4 layers or more layers. With this technical solution, different purposes can be achieved by reasonably selecting the materials of each first sub-metal layer in the first metal layer 2. For example, by selecting the first sub-metal layer, the metal in the second metal layer 3 is prevented from diffusing to the intermediate substrate 1, resulting in a decrease in the short-circuit current density (Jsc); at the same time, multiple first sub-metal layers can reduce the stress of the entire electrode structure and reduce the warpage.

[0345] In another embodiment, the difference between the standard electrode potential of the first metal layer 2 and the standard electrode potential of the second metal layer 3 is 0.1V to 3.5V, and the standard electrode potential of the first metal layer 2 is less than the standard electrode potential of the second metal layer 3. In this way, during the wet etching process, the etching solution preferentially corrodes the first metal layer 2, forming the shape of the side of the first metal layer 2 while ensuring that the second metal layer 3 is not severely corroded. In the case where the first metal layer 2 includes multiple first sub-metal layers, the difference between the standard electrode potential of any first sub-metal layer and the standard electrode potential of the second metal layer 3 is 0.1V to 3.5V. Exemplarily, the difference between the standard electrode potential of the first metal layer 2 and the standard electrode potential of the second metal layer 3 is 0.1V, 0.5V, 1V, 1.5V, 2V, 2.5V, 3V or 3.5V, etc.

[0346] Optionally, the standard electrode potential of the first metal layer 2 is less than the standard electrode potential of the second metal layer 33 . This arrangement ensures that the transmission resistance between the first metal layer 2 and the intermediate substrate 1 is low, thereby reducing current loss.

[0347] From the material point of view, the first metal layer 2 may include one or more of Al, Zn, Fe, Co, Mg, Cu, Ag and their alloys. The second metal layer 3 may include one or more of Cu, Ni, Cr, Ti, W, Mo, Ag, Sn and their alloys. It can be understood that the materials of the first metal layer 2 and the second metal layer 3 are different, and the materials of the first metal layer 2 and the second metal layer 3 cannot be Cu or Ag at the same time.

[0348] In some embodiments, if the thickness of the first metal layer 2 is too small, the resistance of the electrode structure may be large, and the bonding between the first metal layer 2 and the intermediate substrate 1 may not be strong. If the thickness of the second metal layer 3 is too large, the cost may be high. Therefore, the thickness of the first metal layer 2 may be set within a reasonable range of 0.5 μm to 20 μm to ensure that the resistance of the electrode structure is small, the bonding between the first metal layer 2 and the intermediate substrate 1 is strong, and the processing cost is reduced. For example, the thickness of the first metal layer 2 is 0.5 μm, 2 μm, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm or 20 μm, etc.

[0349] Considering that if the thickness of the second metal layer 3 is too small, the welding between the second metal layer 3 and the welding strip or the interconnection part may not be firm, and if the thickness of the second metal layer 3 is too large, the selectivity of the laser is less during the laser patterning process, the thickness of the second metal layer 3 is set within a reasonable range of 5nm to 300nm to ensure that the welding between the second metal layer 3 and the welding strip or the interconnection part is firm, while the selectivity of the laser during the laser patterning process is not limited. For example, the thickness of the second metal layer 3 is 5nm, 25nm, 50nm, 75nm, 100nm, 125nm, 150nm, 175nm, 200nm, 225nm, 250nm, 275nm or 300nm, etc.

[0350] The thickness of the second metal layer 3 is less than or equal to 10% of the thickness of the first metal layer 2 to ensure that the second metal layer 3 is firmly welded to the welding strip or the interconnection component while facilitating the patterning of the second metal layer 3. For example, the laser selectivity used for laser patterning of the second metal layer 3 is greater. For example, the thickness of the second metal layer 3 is 10%, 9%, 8%, 7%, 6% or 5% of the thickness of the first metal layer 2.

[0351] In addition, in the above embodiments, after cleaning the intermediate substrate 1 after laser scanning with the etching liquid, the method for manufacturing a solar cell further includes: cleaning the intermediate substrate 1 with deionized water and drying it, so that the etching liquid remaining on the surface of the intermediate substrate 1 can be removed.

[0352] Specifically, the intermediate substrate 1 is cleaned with deionized water and dried, including: cleaning the intermediate substrate 13 to 5 times with deionized water, each cleaning time is 30 seconds to 2 minutes, and then the intermediate substrate 1 is placed in an oven at a temperature of 50° C. to 100° C. and dried for 10 minutes to 2 minutes.

[0353] The methods for cleaning the intermediate substrate 1 include rinsing, brushing, high-pressure spraying, ultrasonic cleaning and / or nano-bubble cleaning.

[0354] In the manufacturing method of the solar cell provided in the present application, the relationship between the width of the second metal layer 3 in the electrode structure and the width of the upper surface of the first metal layer 2 away from the intermediate substrate 1 can be controlled by adjusting the material of the second metal layer 3 and / or the cleaning method or the cleaning intensity. Exemplarily, if the width of the second metal layer 3 is to be greater than the width of the upper surface of the first metal layer 2 away from the intermediate substrate 1, a metal with strong rigidity and high toughness can be selected to form the second metal layer 3, and a cleaning method with low mechanical strength can be selected. For example, pure Ni can be selected as the second metal layer 3, and then the intermediate substrate is cleaned by an ordinary flushing method, and the width of the second metal layer 3 in the final electrode structure is greater than the width of the surface of the first metal layer 2 away from the intermediate substrate.

[0355] If you want to achieve the purpose of making the width of the second metal layer 3 equal to the width of the first metal layer 2 away from the upper surface of the intermediate substrate 1, you can choose a metal with lower rigidity and lower toughness to form the second metal layer 3, for example, choose a Ni-Cu alloy to form the second metal layer 3. Due to the addition of Cu, the rigidity and toughness of the second metal layer 3 are reduced compared to pure Ni, so that the second metal layer 3 located in the isolation area of ​​the corroded metal layer structure is easier to be peeled off during the cleaning process; in this solution, even if an ordinary cleaning method is selected, the first metal layer 2 and the second metal layer 3 in the isolation area can be removed. Of course, a cleaning method with higher mechanical strength can also be selected. In addition, if a cleaning method with higher mechanical strength is selected, such as a high-pressure spray method to clean the intermediate substrate, the material of the second metal layer 3 does not need to be specifically limited, and you can choose a metal with lower rigidity and lower toughness or a metal with higher rigidity and higher toughness.

[0356] A specific embodiment is provided below:

[0357] In this embodiment, the intermediate substrate 1 includes a semiconductor substrate, a first doped polysilicon layer, a first tunneling oxide layer, a second doped polysilicon layer, a second tunneling oxide layer and a dielectric layer. The first doped polysilicon layer and the second doped polysilicon layer are alternately distributed on the backlight surface of the semiconductor substrate, a first tunneling oxide layer is provided between the first doped polysilicon layer and the semiconductor substrate, and a second tunneling oxide layer is provided between the second doped polysilicon layer and the semiconductor substrate. An isolation region is provided between the first doped polysilicon layer and the second doped polysilicon layer, and the isolation region includes an insulating material and / or an isolation groove. The region corresponding to the first doped polysilicon layer and the region corresponding to the second doped polysilicon layer of the dielectric layer are both provided with openings that penetrate their thickness.

[0358] The method for forming the first electrode and the second electrode on the side of the dielectric layer of the intermediate substrate facing away from the semiconductor substrate comprises:

[0359] Step 1: forming a first metal layer and a second metal layer stacked in sequence on a side of the dielectric layer facing away from the semiconductor substrate, with the first metal layer being located between the second metal layer and the dielectric layer;

[0360] Step 2: Scanning the second metal layer in the isolation area using a laser;

[0361] Step three: Use a corrosive liquid to clean the intermediate substrate after the laser scanning process, and the corrosive liquid etches away the second metal layer modified by the laser scanning and the third metal thereunder. The first metal layer and the second metal layer in the corresponding area of ​​the remaining first doped polysilicon layer form a first electrode, and the first electrode passes through the opening to be electrically connected to the first doped polysilicon layer. The first metal layer and the second metal layer in the corresponding area of ​​the remaining second doped polysilicon layer form a second electrode, and the second electrode passes through the opening to be electrically connected to the first doped polysilicon layer.

[0362] Alternatively, the roughness of the isolation region of the intermediate substrate is greater than the roughness of the corresponding regions of the first doped polysilicon layer and the second doped polysilicon layer, and the method for forming the first electrode and the second electrode on the side of the dielectric layer of the intermediate substrate away from the semiconductor substrate includes:

[0363] Step 1: forming a first metal layer and a second metal layer stacked in sequence on a side of the dielectric layer facing away from the semiconductor substrate, with the first metal layer being located between the second metal layer and the dielectric layer;

[0364] Step 2: Use a corrosive solution to clean the intermediate substrate, and the corrosive solution etches away the second metal layer located in the isolation area and the first metal layer thereunder, and the first metal layer and the second metal layer in the remaining first doped polysilicon layer corresponding area form a first electrode, and the first electrode passes through the opening to be electrically connected to the first doped polysilicon layer, and the first metal layer and the second metal layer in the remaining second doped polysilicon layer corresponding area form a second electrode, and the second electrode passes through the opening to be electrically connected to the first doped polysilicon layer.

[0365] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0366] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for manufacturing a solar cell, characterized in that: include: Providing an intermediate substrate, the intermediate substrate comprising a first surface and a second surface opposite to each other, the first surface comprising an electrode region and an isolation region; sequentially forming a first metal layer and a second metal layer stacked on the first surface, wherein the first metal layer is closer to the intermediate substrate than the second metal layer; Scanning the isolation area with a laser to modify the second metal layer located in the isolation area; The intermediate substrate after laser scanning processing is cleaned by using a corrosive liquid, and the corrosive liquid etches away the modified second metal layer and the first metal layer thereunder, and the remaining first metal layer and second metal layer in the electrode area form an electrode structure; wherein the corrosion resistance of the second metal layer to the corrosive liquid is greater than the corrosion resistance of the first metal layer to the corrosive liquid.

2. The method for manufacturing a solar cell according to claim 1, characterized in that: Scanning the isolation region with a laser to modify the second metal layer located in the isolation region includes: Scanning the isolation area with a laser so that the second metal layer located in the isolation area and the first metal layer thereunder form a metal alloy; the corrosion resistance of the metal alloy to the corrosive liquid is lower than the corrosion resistance of the second metal layer to the corrosive liquid; Alternatively, the step of scanning the isolation region with a laser to modify the second metal layer located in the isolation region includes: Scanning the isolation region by using laser so that the density of the second metal layer located in the isolation region is smaller than the density of the second metal layer located in the electrode region; Alternatively, the step of scanning the isolation region with a laser to modify the second metal layer located in the isolation region includes: The isolation area is scanned by laser so that the second metal layer located in the isolation area and the first metal layer thereunder form a metal alloy, and the density of the metal alloy is lower than the density of the second metal layer located in the electrode area; wherein the corrosion resistance of the metal alloy to the corrosive liquid is lower than the corrosion resistance of the second metal layer to the corrosive liquid.

3. The method for manufacturing a solar cell according to claim 1, characterized in that: The roughness of the isolation region of the intermediate substrate is greater than the roughness of the electrode region of the intermediate substrate; Before modifying the second metal layer located in the isolation region, the density of the second metal layer located in the isolation region is smaller than the density of the second metal layer located in the electrode region.

4. The method for manufacturing a solar cell according to claim 3, characterized in that: The isolation region of the intermediate substrate is a suede structure, and the electrode region of the intermediate substrate is a polished surface structure.

5. The method for manufacturing a solar cell according to claim 1, characterized in that: After providing an intermediate substrate and before sequentially forming a first metal layer and a second metal layer stacked on the first surface, the method for manufacturing a solar cell further includes: forming a transparent conductive layer on the first surface of the intermediate substrate; The intermediate substrate after the laser scanning process is cleaned by using an etching liquid, and the etching liquid etches away the modified second metal layer and the first metal layer thereunder, and the remaining first metal layer and the second metal layer in the electrode region form an electrode structure, including: The intermediate substrate is cleaned by using an etching solution, and the etching solution removes the second metal layer located in the isolation area and the first metal layer and the transparent conductive layer thereunder, so that the first metal layer and the second metal layer in the remaining electrode area form an electrode structure, and the transparent conductive layer in the remaining electrode area forms a transparent conductive pattern; Alternatively, the method for manufacturing a solar cell further comprises: forming a transparent conductive layer on the first surface of the intermediate substrate, and patterning the transparent conductive layer to form a transparent conductive pattern; The method includes sequentially forming a first metal layer and a second metal layer stacked on the first surface, comprising: forming the first metal layer and the second metal layer on the intermediate substrate on which the transparent conductive pattern is formed.

6. The method for manufacturing a solar cell according to claim 5, characterized in that: The etching solution etches away the second metal layer located in the isolation area and the first metal layer and the transparent conductive layer thereunder, and the transparent conductive layer in the remaining electrode area forms a transparent conductive pattern; wherein the width of the transparent conductive pattern is equal to the width of the first metal layer; or, A transparent conductive layer is formed on the first surface of the intermediate substrate, and the transparent conductive layer is processed to form a transparent conductive pattern; wherein the width of the transparent conductive pattern is greater than or equal to the width of the first metal layer.

7. The method for manufacturing a solar cell according to claim 1, characterized in that: After providing an intermediate substrate and before sequentially forming a first metal layer and a second metal layer stacked on the first surface, the method for manufacturing a solar cell further includes: forming a buffer layer on the first surface of the intermediate substrate; The intermediate substrate after laser scanning is cleaned by using a corrosive liquid, and the corrosive liquid etches and removes the modified second metal layer and the first metal layer thereunder, and the remaining first metal layer and the second metal layer in the electrode region form an electrode structure; comprising: The intermediate substrate is cleaned by using an etching solution, wherein the etching solution removes the second metal layer located in the isolation region and the first metal layer and the buffer layer thereunder, and the first metal layer and the second metal layer in the remaining electrode region form an electrode structure, and the buffer layer in the remaining electrode region forms a buffer pattern; Alternatively, the method for manufacturing a solar cell further comprises: forming a buffer layer on the first surface of the intermediate substrate, and patterning the buffer layer to form a buffer pattern; The method includes sequentially forming a first metal layer and a second metal layer stacked on the first surface, and comprising: forming the first metal layer and the second metal layer on the intermediate substrate on which the buffer pattern is formed.

8. The method for manufacturing a solar cell according to claim 7, characterized in that: After providing an intermediate substrate and before sequentially forming a first metal layer and a second metal layer stacked on the first surface, the method for manufacturing a solar cell further includes: forming a dielectric layer on the first surface of the intermediate substrate; The dielectric layer located in the electrode region is opened.

9. The method for manufacturing a solar cell according to claim 8, characterized in that: The electrode structure is recessed at the opening; and / or the roughness of the electrode structure at the opening is greater than the roughness of the electrode structure at other positions; And / or, at the opening, the first metal layer includes a hole.

10. The method for manufacturing a solar cell according to claim 1, characterized in that: After sequentially forming a first metal layer and a second metal layer stacked on the first surface and before scanning the isolation region with a laser, the method for manufacturing a solar cell further includes: forming a protective layer on a side of the second metal layer away from the intermediate substrate; Scanning the isolation region with a laser to modify the second metal layer located in the isolation region includes: scanning the isolation region with a laser to remove a protective layer of the isolation region and modifying the second metal layer located in the isolation region.

11. The method for manufacturing a solar cell according to claim 1, characterized in that: After forming a first metal layer and a second metal layer stacked in sequence on the first surface and before scanning the isolation area with a laser, the method for manufacturing the solar cell further includes: forming a protective layer on the side of the second metal layer away from the intermediate substrate, and removing the protective layer located in the isolation area.

12. The method for manufacturing a solar cell according to claim 10 or 11, characterized in that: The material of the protective layer includes at least one of polyvinylidene fluoride, polypropylene, polyethylene, polystyrene, polyetheretherketone, and polytetrafluoroethylene, and the thickness of the protective layer is 10nm to 500nm; or, The material of the protective layer includes at least one of chitosan, silicone oil, polyvinylidene fluoride, stearic acid, paraffin, ink, non-water-soluble cellulose derivatives, and fluororesin, and the thickness of the protective layer is 0.5 μm to 3 μm.

13. The method for manufacturing a solar cell according to claim 10 or 11, characterized in that: The corrosive solution includes a corrosion inhibitor, and the corrosion inhibitor is used to fill the defects of the protective layer to improve the compactness of the protective layer.

14. The method for manufacturing a solar cell according to claim 10 or 11, characterized in that: After the intermediate substrate after the laser scanning process is cleaned by the etching liquid, the manufacturing method further comprises: The protective layer is removed.

15. The method for manufacturing a solar cell according to claim 1, characterized in that: The intermediate substrate comprises a semiconductor base and a first doped semiconductor layer, the two opposite surfaces of the semiconductor base are the first surface and the second surface respectively, and the first doped semiconductor layer is arranged on the first surface; The electrode structure formed includes a first electrode structure, and the first electrode structure is located on a side of the first doped semiconductor layer away from the semiconductor substrate; Along the width direction of the first electrode structure, a ratio of a width of the first electrode structure to a width of the first doped semiconductor layer is greater than or equal to 0.1 and less than or equal to 1.

1.

16. The method for manufacturing a solar cell according to claim 15, characterized in that: A ratio of a width of the first electrode structure to a width of the first doped semiconductor layer is less than or equal to 1; The orthographic projection of the first electrode structure on the first doped semiconductor layer is located within the boundary of the first doped semiconductor layer, and along the width direction of the first electrode structure, the distance between the edge of the first electrode structure and the edge of the first doped semiconductor layer on the same side is 0 to 40 μm.

17. The method for manufacturing a solar cell according to claim 16, characterized in that: Along the width direction of the first electrode structure, the absolute value of the difference between the distances between any two points on the edge of the first electrode structure and the edge of the first doped semiconductor layer on the same side is ΔD1, and 0≤ΔD1≤40 μm.

18. The method for manufacturing a solar cell according to claim 15, characterized in that: A ratio of a width of the first electrode structure to a width of the first doped semiconductor layer is greater than 1 and less than or equal to 1.1; Along the width direction of the first doped semiconductor layer, the distance that the edge of the first electrode structure exceeds the edge of the first doped semiconductor layer on the same side is 0-10 μm.

19. The method for manufacturing a solar cell according to claim 1, characterized in that: The electrode region includes a first electrode region and a second electrode region; the isolation region is arranged between the first electrode region and the second electrode region; The intermediate substrate after the laser scanning process is cleaned by using an etching liquid, and the etching liquid etches away the modified second metal layer and the first metal layer thereunder, and the remaining first metal layer and the second metal layer in the electrode region form an electrode structure, including: The intermediate substrate is cleaned with a corrosive liquid, and the corrosive liquid etches away the second metal layer located in the isolation area and the first metal layer thereunder, so that the first metal layer and the second metal layer in the remaining first electrode area form a first electrode structure, and the first metal layer and the second metal layer in the remaining second electrode area form a second electrode structure.

20. The method for manufacturing a solar cell according to claim 1, characterized in that: In the electrode structure, along the extension direction of the first metal layer, the boundary of the first metal layer extends in a wave shape; And / or, in the electrode structure, the width of the first metal layer gradually increases along a direction approaching the intermediate substrate.

21. The method for manufacturing a solar cell according to claim 1, characterized in that: The width of the laser irradiation is greater than or equal to the width of the isolation area; And / or, the difference between the width of the laser irradiation and the width of the isolation area is 0-400 um.

22. The method for manufacturing a solar cell according to claim 1, characterized in that: The width of the second metal layer in the electrode structure is greater than or equal to the width of the surface of the first metal layer away from the intermediate substrate; Alternatively, the width of the second metal layer in the electrode structure is greater than the width of the first metal layer away from the surface of the intermediate substrate, and the difference between the width of the second metal layer in the electrode structure and the width of the first metal layer away from the surface of the intermediate substrate is in the range of 1 μm to 30 μm.

23. The method for manufacturing a solar cell according to claim 1, characterized in that: In the step of scanning the isolation region with laser, an inert gas is blown toward the first surface during the process of scanning the isolation region with laser.

24. The method for manufacturing a solar cell according to claim 1, characterized in that: The etching solution includes one or more of NaOH, KOH, HCl, H2SO4, HNO3, H3PO4, tetramethylammonium hydroxide and ammonia water.

25. The method for manufacturing a solar cell according to claim 1, characterized in that: The first metal layer includes one or more of Al, Zn, Fe, Co, Mg, Cu, Ag and their alloys; and / or the second metal layer includes one or more of Cu, Ni, Cr, Ti, W, Mo, Ag, Sn and their alloys.

26. The method for manufacturing a solar cell according to claim 1, characterized in that: The difference between the standard electrode potential of the first metal layer and the standard electrode potential of the second metal layer is 0.1V to 3.5V, and the standard electrode potential of the first metal layer is lower than the standard electrode potential of the second metal layer.

27. The method for manufacturing a solar cell according to claim 1, characterized in that: The thickness of the first metal layer is 0.5 μm to 20 μm; and / or, the thickness of the second metal layer is 5 nm to 300 nm; And / or, the thickness of the second metal layer is less than or equal to 10% of the thickness of the first metal layer.

28. A method for manufacturing a solar cell, characterized in that: include: Providing an intermediate substrate, the intermediate substrate comprising a first surface and a second surface opposite to each other, the first surface comprising an electrode region and an isolation region; The roughness of the isolation region of the intermediate substrate is greater than the roughness of the electrode region of the intermediate substrate; sequentially forming a first metal layer and a second metal layer stacked on the first surface, wherein the first metal layer is closer to the intermediate substrate than the second metal layer; The density of the second metal layer located in the isolation region is less than the density of the second metal layer located in the electrode region; The intermediate substrate is cleaned by using a corrosive liquid, and the corrosive liquid etches away the second metal layer located in the isolation area and the first metal layer thereunder, and the remaining first metal layer and second metal layer in the electrode area form an electrode structure; wherein the corrosion resistance of the second metal layer to the corrosive liquid is greater than the corrosion resistance of the first metal layer to the corrosive liquid.

29. The method for manufacturing a solar cell according to claim 28, characterized in that: After the stacked first metal layer and the second metal layer are sequentially formed on the first surface, and before the intermediate substrate is cleaned with the etching solution, the method for manufacturing a solar cell further includes: The isolation region is scanned by laser to modify the second metal layer located in the isolation region.

30. The method for manufacturing a solar cell according to claim 28, characterized in that: After the first metal layer and the second metal layer are stacked in sequence on the first surface, and before the intermediate substrate is cleaned with a corrosive solution, the method for manufacturing the solar cell further includes: forming a protective layer on the side of the second metal layer away from the intermediate substrate, and removing the protective layer located in the isolation area.

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