Solar cell, manufacturing method thereof and photovoltaic module

Abstract

The invention provides a solar cell, a manufacturing method thereof and a photovoltaic module, and relates to the field of photovoltaic technology. Silver paste with the silver content of 40-80 wt% is used for forming a silver grid line on at least one surface of a solar cell intermediate, and the silver grid line comprises a first grid line segment and a second grid line segment which are different in width; carrying out pre-sintering treatment on the solar cell intermediate on which the silver grid lines are formed; forming a base metal grid line connected with the silver grid line on the silver grid line, and performing curing treatment; and sintering the solar cell intermediate on which the base metal grid lines are formed. By using the silver paste containing low-content silver and combining the silver grid lines with non-uniform width design, the silver grid lines with the height smaller than or equal to 4 microns can be formed on the surface of the intermediate of the solar cell, and then the base metal grid lines are formed on the silver grid lines, so that the same electrode conductivity and cell efficiency are obtained, and the service life of the solar cell is prolonged. And the silver consumption of the solar cell is reduced, so that the cost is reduced.

Description

Technical Field

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

[0002] The main direction for the sustainable development of solar cells is to improve the photoelectric conversion efficiency and reduce the production cost. The electrode grid lines of solar cells are usually made of silver paste, which consumes a lot of silver and has high cost. For example, for Tunnel Oxide Passivated Contact (TOPCon) cells, the cost of silver paste is the second largest raw material cost after the cost of silicon substrate. The thinning of the grid lines is an effective solution to improve cell efficiency and reduce the consumption of silver paste. After the grid lines are thinned, in order to meet the demand for high efficiency, the number of grid lines is usually increased, resulting in an increase in the silver consumption of solar cells.

[0003] There are currently two main methods for making solar cell electrodes, namely screen printing technology and copper electroplating technology. Screen printing is limited by the printability of the slurry and the screen manufacturing process, and there is limited room for further reduction in the silver consumption of the electrode. In order to meet the contact performance and high efficiency, the silver consumption of screen printing is still relatively high. The application of copper electroplating technology can greatly reduce the width of the electrode grid line to reduce the shading area and avoid the use of high-cost silver paste. However, the process of copper electroplating technology is complicated and cumbersome, and the long-term reliability of the copper grid line after electroplating and the high cost of waste liquid treatment limit its large-scale application. Summary of the invention

[0004] In order to alleviate, mitigate or eliminate the above-mentioned technical problems, the present application provides a solar cell and a manufacturing method thereof, and a photovoltaic module to reduce the silver consumption of the solar cell.

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

[0006] Providing solar cell intermediates;

[0007] Using silver paste to form silver grid lines on at least one surface of the solar cell intermediate, the silver paste contains silver, and the silver content in the silver paste is 40-80wt%; the silver grid lines include a first grid line segment and a second grid line segment, and the first grid line segment and the second grid line segment have different widths;

[0008] Performing a pre-sintering treatment on the solar cell intermediate body with the silver grid lines formed thereon;

[0009] forming a base metal grid line connected to the silver grid line on the silver grid line, and performing a curing process;

[0010] The solar cell intermediate body formed with the base metal grid lines is subjected to a sintering process.

[0011] In a possible implementation, the pre-sintering temperature is 600-800°C, and the curing temperature is 200-300°C.

[0012] In a possible implementation, a laser is used to perform a sintering process on the solar cell intermediate formed with the base metal grid lines, and the power of the laser is 30-80W.

[0013] In a possible implementation, the method for forming the silver grid line includes:

[0014] Silver grid lines are printed on at least one surface of the solar cell intermediate using a screen, and the screen film thickness is less than or equal to 2 μm.

[0015] In a possible implementation, the first gate line segment includes silver dots, the second gate line segment includes silver wires, the silver wires connect the silver dots, the length of the silver wire between two adjacent silver dots is 50-500 μm, and the width of the silver wires is smaller than the width of the silver dots.

[0016] In a possible implementation, the width of the base metal grid line completely covers the width of the silver grid line.

[0017] In a possible implementation, the width of the silver line is 10-30 μm, the width of the silver dot is 20-200 μm, and the width of the base metal grid line is 20-300 μm.

[0018] In a possible implementation, the base metal grid line includes a silver-clad copper wire, and the silver content of the silver-clad copper wire is 20-40 wt %.

[0019] In a second aspect, the present application provides a solar cell, comprising:

[0020] a silicon substrate having two surfaces in a thickness direction;

[0021] A silver grid line is located on at least one surface of the silicon substrate, and the height of the silver grid line is less than or equal to 4 μm; the silver grid line includes a first grid line segment and a second grid line segment, and the first grid line segment and the second grid line segment have different widths;

[0022] The base metal grid line is located on the silver grid line and connected to the silver grid line.

[0023] In a possible implementation, the first gate line segment includes silver dots, the second gate line segment includes silver wires, the silver wires connect the silver dots, the length of the silver wire between two adjacent silver dots is 50-500 μm, and the width of the silver wires is smaller than the width of the silver dots.

[0024] In a possible implementation, the width of the base metal grid line completely covers the width of the silver grid line.

[0025] In a possible implementation, the width of the silver line is 10-30 μm, the width of the silver dot is 20-200 μm, and the width of the base metal grid line is 20-300 μm.

[0026] In a possible implementation, the base metal grid line includes a silver-clad copper wire, and the silver content of the silver-clad copper wire is 20-40 wt %.

[0027] In a third aspect, the present application provides a photovoltaic assembly, comprising a plurality of solar cell strings, wherein the solar cell strings are composed of the solar cells described in the second aspect.

[0028] Compared with the prior art, this application has the following advantages:

[0029] The present application provides a solar cell and a manufacturing method thereof, and a photovoltaic module, and relates to the field of photovoltaic technology. The present application uses a silver paste with a silver content of 40-80wt% to form silver grid lines on at least one surface of a solar cell intermediate, and the silver grid lines include a first grid line segment and a second grid line segment with different widths; pre-sintering the solar cell intermediate formed with the silver grid lines; forming a base metal grid line connected to the silver grid line on the silver grid line, and performing a curing treatment; sintering the solar cell intermediate formed with the base metal grid line. The present application uses a silver paste containing a low silver content, combined with a silver grid line with a non-uniform width design, to form a silver grid line with a height of less than or equal to 4μm on the surface of the solar cell intermediate, and then forms a base metal grid line on the silver grid line, while obtaining the same electrode conductivity and battery efficiency, reducing the silver consumption of the solar cell, thereby reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0031] Figure 1 It is a schematic flow chart of a method for manufacturing a solar cell provided in an embodiment of the present application;

[0032] Figure 2 is a schematic structural diagram of a solar cell provided in an embodiment of the present application;

[0033] Figure 3 is a schematic structural diagram of an electrode of a solar cell provided in an embodiment of the present application;

[0034] Figure 4It is a structural schematic diagram of a silver grid line provided in an embodiment of the present application;

[0035] Figure 5 is a schematic diagram of the structure of another silver grid line provided in an embodiment of the present application;

[0036] Figure 6 It is a schematic flow chart of another method for manufacturing a solar cell provided in an embodiment of the present application. DETAILED DESCRIPTION

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0038] As shown in this application, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0039] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0040] In addition, although the terms used in this application are selected from well-known and commonly used terms, some of the terms mentioned in this application specification may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0041] It should be understood that when a component is referred to as being “on another component,” “connected to another component,” “coupled to another component,” or “contacting another component,” it can be directly on, connected to, coupled to, or contacting the other component, or intervening components may be present. In contrast, when a component is referred to as being “directly on another component,” “directly connected to,” “directly coupled to,” or “directly contacting” another component, there are no intervening components present.

[0042] Flowcharts are used in the present application to illustrate the operations performed by the methods according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0043] Figure 1 It is a schematic flow chart of a method for manufacturing a solar cell provided in an embodiment of the present application.

[0044] like Figure 1 As shown, the method for manufacturing a solar cell comprises the following steps:

[0045] Step S110: providing a solar cell intermediate.

[0046] Please refer to Figure 2 , a solar cell intermediate can be obtained by performing certain pretreatment and / or coating treatment on the silicon substrate 201. Pretreatment includes but is not limited to cleaning, polishing, and texturing. Coating treatment is to form a specific film layer 202 on the surface of the silicon substrate, such as a silicon dioxide layer, an intrinsic amorphous silicon layer, a doping layer, etc. The film layer 202 may include one or more film layers. The solar cell intermediate has two surfaces in the thickness direction thereof, such as the front and back surfaces in the thickness direction thereof. When the solar cell is working, the front side faces the sun.

[0047] Step S120, forming silver gridlines on at least one surface of the solar cell intermediate body using silver paste, wherein the silver paste contains silver, and the silver content in the silver paste is 40-80wt%. The silver gridlines include a first gridline segment and a second gridline segment, and the first gridline segment and the second gridline segment have different widths.

[0048] The silver paste used to form the silver grid line includes components such as silver, glass powder and organic solvent, and the sum of the contents of the components in the silver paste is 100%. In an embodiment of the present application, in addition to silver, glass powder and organic solvent, the silver paste may also include additives, or other metals. In one example, the silver content in the silver paste is 40-80wt%, such as 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, etc., the content of the glass powder is 5-10wt%, such as 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, etc., and the content of the organic solvent is 5-20wt%, such as 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, 20wt%, etc. The formed silver grid line includes a first grid line segment and a second grid line segment, and the widths of the first grid line segment and the second grid line segment are different. The silver content in the existing silver paste used to form silver grid lines is generally 90wt%, while the silver content in the silver paste of the embodiment of the present application is less than 80wt%, and the viscosity is low. Combined with the silver grid lines with non-uniform width design, the height of the silver grid lines is reduced, thereby reducing the silver consumption while ensuring good silver-silicon contact performance. The embodiment of the present application can achieve a silver grid line height of less than or equal to 4μm.

[0049] The silver grid lines can be printed on the surface in the middle of the solar cell by screen printing process using a screen, or can be sprayed on the surface in the middle of the solar cell by spraying process. In some embodiments, the silver grid lines are printed on at least one surface of the solar cell intermediate using a screen, wherein the screen film thickness is less than or equal to 2 μm, further achieving the thinning of the silver grid lines.

[0050] It should be noted that forming silver grid lines on at least one surface of the solar cell intermediate means that the silver grid lines can be formed only on the front side of the solar cell intermediate, or only on the back side of the solar cell intermediate, or on both the front side and the back side of the solar cell intermediate.

[0051] Please refer to Figure 2-Figure 5 The silver grid line 203 includes a first grid line segment 2031 and a second grid line segment 2032 of different widths. The silver grid line 203 may include one or more first grid line segments 2031, and may also include one or more second grid line segments 2032. The first grid line segment 2031 and the second grid line segment 2032 may be grid line segments with uniform widths, or grid line segments with gradually varying widths. The embodiment of the present application does not limit the widths of the two, as long as the widths of the two are different.

[0052] In some embodiments, the first grid line segment 2031 and the second grid line segment 2032 are grid line segments of uniform width, and the two are arranged alternately. In one example, the first grid line segment 2031 includes silver dots, which can now be rectangular or circular. The second grid line segment 2032 includes a silver line, which connects the silver dots, and the length of the silver line between two adjacent silver dots is 50-500μm, such as 50μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm. The width of the silver line is smaller than the width of the silver dot. For example, the width of the silver line is 10-30μm, such as 10μm, 15μm, 20μm, 25μm, 30μm, and the width of the silver dot is 20-200μm, such as 20μm, 50μm, 80μm, 100μm, 120μm, 150μm, 180μm, 200μm. The silver grid lines designed with non-uniform widths are combined with special silver paste to reduce the height of the silver grid lines, thereby ensuring contact performance while reducing silver consumption. It can be understood that when the shape of the silver dot is a rectangle, the width of the silver dot is the width of the rectangle in a direction perpendicular to the extension direction of the silver grid lines. When the shape of the silver dot is a circle, the width of the silver dot is the diameter length of the circle in a direction perpendicular to the extension direction of the silver grid lines. The same is true for the widths of silver dots of other shapes.

[0053] Step S130 , pre-sintering the solar cell intermediate body formed with the silver grid lines.

[0054] Step S140 , forming a base metal grid line connected to the silver grid line on the silver grid line, and performing a curing process.

[0055] Base metals refer to cheap metals, such as copper, aluminum, lead, etc. In an embodiment of the present application, the base metal grid lines may contain precious metal components, and their overall unit price is still significantly lower than that of silver grid lines. In one example, the base metal grid lines include silver-clad copper wires. The silver content in the silver-clad copper wires is 20-40wt%, such as 20wt%, 25wt%, 30wt%, 35wt%, and 40wt%. Using silver-clad copper wires with a silver content of 20-40wt%, while reducing silver consumption, ensures a lower grid line resistivity.

[0056] The melting point of base metals is usually low. In the embodiment of the present application, the silver grid lines are pre-sintered before forming the base metal grid lines to reduce the resistivity of the formed grid lines. In one example, the pre-sintering temperature is 600-800°C, such as 600°C, 650°C, 700°C, 750°C, 800°C, the curing temperature is 200-300°C, such as 200°C, 230°C, 250°C, 280°C, 300°C, and the curing time is 10-30min, such as 10min, 15min, 20min, 25min, 30min.

[0057] Please refer to Figure 2 and Figure 3 The width of the base metal grid line 204 completely covers the width of the silver grid line 203, that is, the width of the base metal grid line 204 is equal to or slightly larger than the width of the silver grid line 203, thereby improving the contact performance. In one example, the width of the base metal grid line 204 is 20-300 μm, such as 20 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 220 μm, 250 μm, 280 μm, and 300 μm.

[0058] Step S150 , sintering the solar cell intermediate formed with the base metal grid lines.

[0059] In some embodiments, a laser is used to sinter the solar cell intermediate formed with the base metal grid lines, wherein the laser power is 30-80W, such as 30W, 40W, 50W, 60W, 70W, 80W, and the bias voltage is 10-15V, such as 10V, 11V, 12V, 13V, 14V, 15V.

[0060] Figure 2 This is a schematic diagram of the structure of a solar cell provided in an embodiment of the present application. Figure 2-Figure 5 The solar cell includes a silicon substrate 201, a silver grid line 203 and a base metal grid line 204. A film layer 202 is also included between the silicon substrate 201 and the silver grid line 203, and the film layer 202 may include one or more film layers.

[0061] The silver grid line 203 is located on at least one surface of the silicon substrate 201, and the height of the silver grid line 203 is less than or equal to 4μm, such as 1μm, 2μm, 3μm, and 4μm. The silver grid line 203 includes a first grid line segment 2031 and a second grid line segment 2032 of different widths. The silver grid line 203 may include one or more first grid line segments 2031, and may also include one or more second grid line segments 2032. The first grid line segment 2031 and the second grid line segment 2032 may be grid line segments with uniform widths, or grid line segments with gradually varying widths. The embodiment of the present application does not limit the width form of the two, as long as the widths of the two are different.

[0062] In some embodiments, the first grid line segment 2031 and the second grid line segment 2032 are grid line segments of uniform width, and the two are arranged alternately. In one example, the first grid line segment 2031 includes silver dots, which can now be rectangular or circular. The second grid line segment 2032 includes a silver line, which connects the silver dots, and the length of the silver line between two adjacent silver dots is 50-500μm, such as 50μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm. The width of the silver line is smaller than the width of the silver dot. For example, the width of the silver line is 10-30μm, such as 10μm, 15μm, 20μm, 25μm, 30μm, and the width of the silver dot is 20-200μm, such as 20μm, 50μm, 80μm, 100μm, 120μm, 150μm, 180μm, 200μm. The silver grid lines designed with non-uniform widths can ensure contact performance while reducing silver consumption. It can be understood that when the shape of the silver dot is a rectangle, the width of the silver dot is the width of the rectangle in a direction perpendicular to the extension direction of the silver grid lines. When the shape of the silver dot is a circle, the width of the silver dot is the diameter length of the circle in a direction perpendicular to the extension direction of the silver grid lines. The same is true for the widths of silver dots of other shapes.

[0063] The base metal grid line 204 is located on the silver grid line 203 and connected to the silver grid line 203. The width of the base metal grid line 204 completely covers the width of the silver grid line 203, that is, the width of the base metal grid line 204 is equal to or slightly larger than the width of the silver grid line 203, thereby improving the contact performance. In one example, the width of the base metal grid line 204 is 20-300 μm, such as 20 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 220 μm, 250 μm, 280 μm, and 300 μm.

[0064] In one example, the base metal grid line includes a silver-clad copper wire. The silver content in the silver-clad copper wire is 20-40wt%, such as 20wt%, 25wt%, 30wt%, 35wt%, 40wt%. Using the silver-clad copper wire with a silver content of 20-40wt% can reduce the silver consumption while ensuring a lower grid line resistivity.

[0065] The embodiment of the present application adopts a hybrid electrode structure with base metal grid lines superimposed on ultra-thin silver grid lines of non-uniform width, which reduces the silver consumption of the electrode grid lines while ensuring the battery efficiency. The electrode contact resistivity of the hybrid electrode structure can be controlled below 1 milliohm·square centimeter, and the volume resistivity is kept below 5 microohm·centimeter. The conductivity of the hybrid electrode is close to that of the pure silver grid line electrode, and the battery efficiency is basically the same.

[0066] The grid lines of a solar cell can be formed on the front and back of the cell, or only on the back of the cell, which is often called a back contact (BC) type solar cell, where there is no grid line on the front side of the cell (i.e., the light-facing side). The grid lines of a solar cell are mainly composed of a main grid line (Busbar, BB) and a secondary grid line (also known as a finger), wherein the main grid line mainly serves to collect the current of the secondary grid line and connect them in series, and the secondary grid line is used to collect photogenerated carriers. Busbar-free (0BB) solar cells have been widely used due to their low cost advantage. The above-mentioned hybrid electrode can be implemented as a main grid electrode or as a secondary grid electrode.

[0067] In order to better understand the present application, the manufacturing method of the solar cell is further described below with reference to a specific example. In this specific example, the front and back sides of the solar cell are both formed with main grid lines and auxiliary grid lines, and the above-mentioned hybrid electrode is only formed on the back side of the cell as the auxiliary grid electrode on the back side.

[0068] Please refer to Figure 6 , the manufacturing method of the solar cell comprises the following steps:

[0069] Step S610: providing a solar cell intermediate.

[0070] Step S620: forming a main grid line on the back side of the solar cell intermediate body.

[0071] Step S630: forming silver grid lines on the back side of the solar cell intermediate body.

[0072] Step S640: forming main grid lines and auxiliary grid lines on the front side of the solar cell intermediate body.

[0073] Step S650: pre-sintering the solar cell intermediate.

[0074] Step S660: forming a base metal grid line connected to the silver grid line on the back side of the solar cell intermediate body, and performing a curing process.

[0075] Step S670: sintering the solar cell intermediate.

[0076] The basic concepts have been described above. Obviously, for those skilled in the art, the above invention disclosure is only used as an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0077] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0078] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of the present application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the subject of the present application requires more features than the features mentioned. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0079] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining the digits. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0080] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the present application.

Claims

1. A method for manufacturing a solar cell, characterized in that: include: Providing solar cell intermediates; Using silver paste to form silver grid lines on at least one surface of the solar cell intermediate, the silver paste contains silver, and the silver content in the silver paste is 40-80wt%; the silver grid lines include a first grid line segment and a second grid line segment, and the first grid line segment and the second grid line segment have different widths; Performing a pre-sintering treatment on the solar cell intermediate body with the silver grid lines formed thereon; forming a base metal grid line connected to the silver grid line on the silver grid line, and performing a curing process; The solar cell intermediate body formed with the base metal grid lines is subjected to a sintering process.

2. The manufacturing method according to claim 1, characterized in that The pre-sintering temperature is 600-800℃ and the curing temperature is 200-300℃.

3. The manufacturing method according to claim 1, characterized in that: The solar cell intermediate formed with the base metal grid lines is sintered by using a laser, wherein the power of the laser is 30-80W.

4. The manufacturing method according to claim 1, characterized in that: The method of forming the silver grid line includes: Silver grid lines are printed on at least one surface of the solar cell intermediate using a screen, and the screen film thickness is less than or equal to 2 μm.

5. The manufacturing method according to any one of claims 1 to 4, characterized in that: The first gate line segment includes silver dots, and the second gate line segment includes silver wires, the silver wires connect the silver dots, and the length of the silver wire between two adjacent silver dots is 50-500 μm, and the width of the silver wire is smaller than the width of the silver dots.

6. The manufacturing method according to any one of claims 1 to 4, characterized in that: The width of the base metal grid line completely covers the width of the silver grid line.

7. The manufacturing method according to claim 5, characterized in that: The width of the silver line is 10-30 μm, the width of the silver dot is 20-200 μm, and the width of the base metal grid line is 20-300 μm.

8. The manufacturing method according to any one of claims 1 to 4, characterized in that: The base metal grid line comprises a silver-clad copper wire, and the silver content of the silver-clad copper wire is 20-40 wt %.

9. A solar cell, characterized in that: include: a silicon substrate having two surfaces in a thickness direction; A silver grid line is located on at least one surface of the silicon substrate, and the height of the silver grid line is less than or equal to 4 μm; the silver grid line includes a first grid line segment and a second grid line segment, and the first grid line segment and the second grid line segment have different widths; The base metal grid line is located on the silver grid line and connected to the silver grid line.

10. The solar cell according to claim 9, characterized in that The first gate line segment includes silver dots, and the second gate line segment includes silver wires, the silver wires connect the silver dots, and the length of the silver wire between two adjacent silver dots is 50-500 μm, and the width of the silver wire is smaller than the width of the silver dots.

11. The solar cell according to claim 9 or 10, characterized in that: The width of the base metal grid line completely covers the width of the silver grid line.

12. The solar cell according to claim 10, wherein: The width of the silver line is 10-30 μm, the width of the silver dot is 20-200 μm, and the width of the base metal grid line is 20-300 μm.

13. The solar cell according to any one of claims 9 to 12, characterized in that: The base metal grid line comprises a silver-clad copper wire, and the silver content of the silver-clad copper wire is 20-40 wt %.

14. A photovoltaic module, characterized in that: The invention comprises a plurality of solar cell strings, wherein the solar cell strings are composed of the solar cells according to any one of claims 9 to 13.

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