Low-cost solar cell and solar cell pack
By replacing the main gate line and thin gate line of the solar cell with aluminum, and setting a silver conductive connection point between the thin gate line and the solar cell body, the problem of high manufacturing cost of solar cells is solved and a low-cost solar cell module is realized.
Patent Information
- Application Number
- CN202420414695.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-04
- Publication Date
- 2025-02-28
- Estimated Expiration
- 2034-03-04
AI Technical Summary
The manufacturing cost of existing solar cells is high, which affects the industrialization process.
By replacing the material of the main gate line and the thin gate line with aluminum from traditional silver, and setting a conductive connection point of the silver material between the thin gate line and the solar cell body, the photocurrent is collected using the more expensive silver and collecting the photocurrent through the cheaper aluminum.
Without reducing the photoelectric efficiency of the solar cell, the cost is reduced and a low-cost solar cell module is realized.
Smart Images
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Abstract
Description
Technical Field
[0001] The present application relates to the field of new energy, and in particular to solar cells. Background Art
[0002] At present, the interconnection method of solar cells to form battery groups is usually to use a welding ribbon to connect the main grid lines of the battery cells. The crystalline silicon solar cells currently produced on a large scale generally include: a battery body, a main grid line and a thin grid line arranged on the battery body, a welding pad arranged on the main grid line, and a welding ribbon welded to the main grid line and the welding pad. The welding pad has a large area, a strong bonding force with the battery body, and provides a higher welding tension; the main grid line is used to collect current, and its width is higher than the thin grid line. The width of the main grid line is also lower than the welding pad, so as to effectively increase the light-receiving area on the front of the component and improve the photoelectric conversion efficiency. The high manufacturing cost of solar cells is the main factor affecting the industrialization of this technology. Among them, the low-temperature silver paste used to form the grid lines on both sides of the battery accounts for a large part of the non-silicon cost. Utility Model Content
[0003] The embodiments of the present application provide a low-cost solar cell and a solar cell group to solve the technical problem of high manufacturing cost of solar cells.
[0004] In a first aspect, an embodiment of the present application provides a low-cost solar cell, the low-cost solar cell comprising: a solar cell body, and an electrode disposed on the solar cell body, the electrode comprising:
[0005] A plurality of main grid lines, wherein the main grid lines are arranged on the solar cell body and are arranged parallel to each other;
[0006] Solder pads, each of the main grid lines is provided with a plurality of the solder pads, and the solder pads are fixedly and electrically connected to the main grid lines;
[0007] A plurality of fine grid lines, wherein the fine grid lines are arranged on the solar cell sheet body, and are connected to different main grid lines through the fine grid lines, and the plurality of fine grid lines are arranged in parallel with each other, and the fine grid lines are perpendicular to the main grid lines;
[0008] A plurality of conductive connection points, wherein the conductive connection points are arranged between the thin grid lines and the solar cell body,
[0009] Wherein, the material of the main grid line is aluminum, the material of the fine grid line is aluminum, and the material of the conductive connection point is silver.
[0010] In some embodiments of the present application, the conductive connection point is not completely covered by the fine grid line.
[0011] In some embodiments of the present application, a plurality of the conductive connection points are distributed in a rectangular array on the solar cell body.
[0012] In some embodiments of the present application, the width of the main grid line is 40-60 μm; and / or,
[0013] The width of the fine gate line is 15-30 μm.
[0014] In some embodiments of the present application, the conductive connection point is in the shape of a rectangle with a length of 50 to 70 μm and a width of 45 to 60 μm.
[0015] In some embodiments of the present application, the conductive connection point is in the shape of an ellipse, with a major axis length of 60 to 140 μm and a minor axis length of 40 to 110 μm.
[0016] In some embodiments of the present application, the distance between adjacent main grid lines is 25 to 35 mm; and / or,
[0017] The distance between adjacent fine grid lines is 0.75-1.5 mm.
[0018] In some embodiments of the present application, the distance between adjacent conductive connection points is 30-40 mm.
[0019] In a second aspect, an embodiment of the present application provides a method for preparing a low-cost solar cell, wherein the low-cost solar cell is the low-cost solar cell described in any embodiment of the first aspect, and the method comprises the following steps:
[0020] Providing a solar cell body;
[0021] Printing silver paste on the solar cell body and then drying it to form prefabricated conductive connection points to obtain a first prefabricated solar cell;
[0022] Printing aluminum paste on the first prefabricated cell and then drying it to form a prefabricated grid line structure to obtain a second prefabricated cell;
[0023] The second prefabricated cell sheet is treated at high temperature so that the prefabricated conductive connection point is sintered to form the conductive connection point, and the prefabricated grid line structure is sintered to form the main grid line, the pad, and the thin grid line to obtain the low-cost solar cell.
[0024] In a third aspect, an embodiment of the present application provides a solar cell group, the solar cell group comprising:
[0025] Several low-cost solar cells, wherein the low-cost solar cells are the low-cost solar cells described in the first aspect, or the low-cost solar cells prepared by the method described in the second aspect;
[0026] A welding strip is welded to the main grid lines and welding pads of the plurality of low-cost solar cells.
[0027] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:
[0028] The low-cost solar cell provided in the embodiment of the present application is achieved by replacing the material of the main grid wire and the fine grid wire from traditional silver to aluminum, and setting conductive connection points between the fine grid wire and the solar cell body with silver. The photocurrent generated by the solar cell body is fully collected by the more expensive silver, and the photocurrent collected by the conductive connection points is collected by the less expensive aluminum, thereby reducing the cost without reducing the photoelectric efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0031] Figure 1 A schematic diagram of the structure of a low-cost solar cell provided in an embodiment of the present application;
[0032] Figure 2 For this application Figure 1 Schematic diagram of the enlarged area A in the middle. DETAILED DESCRIPTION
[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.
[0034] Unless otherwise specified, the terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. In the event of a conflict, this specification takes precedence.
[0035] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0036] Existing solar cells have the technical problem of being too costly.
[0037] The technical solution provided by the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:
[0038] In the first aspect, the present application embodiment provides a low-cost solar cell. Figure 1 , Figure 2 , Figure 1 is a schematic structural diagram of the low-cost solar cell; Figure 2 For this application Figure 1 Schematic diagram of the enlarged area A in the middle.
[0039] A low-cost solar cell, comprising: a solar cell body, and an electrode arranged on the solar cell body, wherein the electrode comprises:
[0040] A plurality of main grid lines 2, wherein the main grid lines 2 are arranged on the solar cell body and the main grid lines 2 are arranged parallel to each other;
[0041] Solder pads 3, each of the main grid lines 2 is provided with a plurality of the solder pads 3, and the solder pads 3 are fixedly and electrically connected to the main grid lines 2;
[0042] A plurality of fine grid lines 4, wherein the fine grid lines 4 are arranged on the solar cell body, and are connected to different main grid lines 2 through the fine grid lines 4, and the fine grid lines 4 are arranged parallel to each other, and the fine grid lines 4 are perpendicular to the main grid lines 2;
[0043] A plurality of conductive connection points 5, wherein the conductive connection points 5 are arranged between the thin grid lines 4 and the solar cell body,
[0044] The main grid line 2 is made of aluminum, the fine grid line 4 is made of aluminum, and the conductive connection point 5 is made of silver.
[0045] It is easy to understand that the main grid line 2, the pad 3, and the thin grid line 4 are conventional structures in the art, and are generally formed by sintering a conductive paste, and the main material thereof is a metal conductor formed by sintering a conductive paste.
[0046] In the present application, the material of the main grid line 2 is replaced by aluminum from traditional silver, and the material of the fine grid line 4 is replaced by aluminum from traditional silver. At the same time, a conductive connection point 5 is set between the fine grid line 4 and the solar cell body using silver as the material. Silver has high conductivity, and the formed conductive connection point 5 can fully collect the photocurrent generated by the solar cell body; aluminum is relatively cheap and also has good conductivity, and can well collect the photocurrent collected by the conductive connection point 5.
[0047] The present application replaces the material of the main grid line 2 and the thin grid line 4 from traditional silver to aluminum, and sets a conductive connection point 5 made of silver between the thin grid line 4 and the solar cell body. The photocurrent generated by the solar cell body is fully collected by the more expensive silver, and the photocurrent collected by the conductive connection point 5 is collected by the cheaper aluminum, thereby reducing the cost without reducing the photoelectric efficiency of the solar cell.
[0048] In some embodiments of the present application, the conductive connection points 5 are not completely covered by the fine grid lines 4 .
[0049] The conductive connection point 5 is not completely covered by the fine grid line 4, so that it has a larger contact area with the solar cell body and can fully collect photocurrent. At the same time, its covered part is staggered with the fine grid line 4, and the fine grid line 4 itself also has a certain ability to collect photocurrent. In this way, the overall photocurrent collection capacity of the fine grid line 4 and the conductive connection point 5 can be increased as much as possible.
[0050] In some embodiments of the present application, a plurality of the conductive connection points 5 are distributed in a rectangular array on the solar cell body.
[0051] The conductive connection points 5 are distributed in a rectangular array on the solar cell body, that is, any pair of adjacent conductive connection points 5 on the same fine grid line 4 have the same spacing; the conductive connection points 5 on different fine grid lines 4 are aligned with each other. This distribution method has regularity, which is conducive to printing operations. At the same time, the conductive connection points 5 are evenly distributed on the fine grid lines 4, which also makes it difficult for the fine grid lines 4 to be subjected to external forces (for example, when the welding ribbon welded to the main grid line 2 is pulled, the tension is transmitted to the fine grid line 4). The situation of tension concentrated on a certain conductive connection point 5 makes the conductive connection point 5 and the fine grid line 4 more firmly connected as a whole.
[0052] In some embodiments of the present application, the width of the main grid line 2 is 40-60 μm; and / or,
[0053] The width of the thin gate line 4 is 15-30 μm.
[0054] As an example, the width of the main grid line 2 may be 40 μm, 45 μm, 50 μm, 55 μm, or 60 μm.
[0055] As an example, the width of the thin gate line 4 may be 15 μm, 20 μm, 25 μm, or 30 μm.
[0056] In some embodiments of the present application, the conductive connection point 5 is in the shape of a rectangle, with a length of 50 to 70 μm and a width of 45 to 60 μm.
[0057] In some embodiments of the present application, the conductive connection point 5 is in the shape of an ellipse, with a major axis length of 70 to 150 μm and a minor axis length of 40 to 110 μm.
[0058] It is easy to understand that the shapes of the conductive connection points 5 are rectangular or elliptical as just two specific examples, and the conductive connection points 5 can be in any shape.
[0059] In some embodiments of the present application, the distance between adjacent main grid lines 2 is 25 to 35 mm; and / or,
[0060] The distance between adjacent thin grid lines 4 is 0.75-1.5 mm.
[0061] As an example, the distance between adjacent main grid lines 2 may be 25 mm, 28 mm, 30 mm, 22 mm, or 35 mm.
[0062] In some embodiments of the present application, the distance between adjacent conductive connection points 5 is 30-40 mm.
[0063] As an example, the distance between adjacent conductive connection points 5 may be 30 mm, 32 mm, 35 mm, 38 mm, or 40 mm.
[0064] In a second aspect, an embodiment of the present application provides a method for preparing a low-cost solar cell, wherein the low-cost solar cell is the low-cost solar cell described in any embodiment of the first aspect, and the method comprises the following steps:
[0065] S1: Provide the solar cell body;
[0066] S2: printing silver paste on the solar cell body and drying it to form prefabricated conductive connection points 5, thereby obtaining a first prefabricated solar cell;
[0067] S3: printing aluminum paste on the first prefabricated cell and drying it to form a prefabricated grid line structure to obtain a second prefabricated cell;
[0068] S4: high temperature treatment of the second prefabricated cell sheet, so that the prefabricated conductive connection point 5 is sintered and formed, and the prefabricated grid line structure is sintered and formed into the main grid line 2, the pad 3, and the thin grid line 4, to obtain the low-cost solar cell.
[0069] It is easy to understand that the silver material formed after drying in step S2 forms the conductive connection point 5 after sintering in step S4. The aluminum material formed after drying in step S3 forms the main grid line 2, the pad 3 and the thin grid line 4 after sintering in step S4.
[0070] The drying can be carried out according to conventional methods in the art, for example, drying at 50-80°C.
[0071] The high temperature treatment can be carried out according to conventional methods in the art, such as sintering at 500-850°C.
[0072] In a third aspect, an embodiment of the present application provides a solar cell group, the solar cell group comprising:
[0073] Several low-cost solar cells, wherein the low-cost solar cells are the low-cost solar cells described in the first aspect, or the low-cost solar cells prepared by the method described in the second aspect;
[0074] A welding strip is welded to the main grid lines 2 and the welding pads 3 of the plurality of low-cost solar cells.
[0075] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to industry standards. If there is no corresponding industry standard, then the conditions recommended by the manufacturer are followed.
[0076] Example 1
[0077] This embodiment provides a low-cost solar cell, the low-cost solar cell comprising: a solar cell body, and an electrode disposed on the solar cell body, the electrode comprising:
[0078] A plurality of main grid lines 2, wherein the main grid lines 2 are arranged on the solar cell body and the main grid lines 2 are arranged parallel to each other;
[0079] Solder pads 3, each of the main grid lines 2 is provided with a plurality of the solder pads 3, and the solder pads 3 are fixedly and electrically connected to the main grid lines 2;
[0080] A plurality of fine grid lines 4, wherein the fine grid lines 4 are arranged on the solar cell body, and are connected to different main grid lines 2 through the fine grid lines 4, and the fine grid lines 4 are arranged parallel to each other, and the fine grid lines 4 are perpendicular to the main grid lines 2;
[0081] A plurality of conductive connection points 5, wherein the conductive connection points 5 are arranged between the thin grid lines 4 and the solar cell body,
[0082] The main grid line 2 is made of aluminum, the fine grid line 4 is made of aluminum, and the conductive connection point 5 is made of silver.
[0083] The solar cell body 1 has a length of 183.75 mm, a width of 182 mm, and a thickness of 135 μm.
[0084] The conductive connection points 5 are not completely covered by the fine grid lines 4 .
[0085] The plurality of conductive connection points 5 are distributed in a rectangular array on the solar cell body.
[0086] The width of the main grid line 2 is 45 μm, and the width of the fine grid line 4 is 20 μm.
[0087] The conductive connection point 5 is in the shape of a rectangle, with a length of 60 μm and a width of 50 μm;
[0088] The distance between adjacent main grid lines 2 is 30 mm, and the distance between adjacent thin grid lines 4 is 1.5 mm.
[0089] The distance between adjacent conductive connection points 5 is 30 mm.
[0090] Example 2
[0091] This embodiment provides a low-cost solar cell, the low-cost solar cell comprising: a solar cell body, and an electrode disposed on the solar cell body, the electrode comprising:
[0092] A plurality of main grid lines 2, wherein the main grid lines 2 are arranged on the solar cell body and the main grid lines 2 are arranged parallel to each other;
[0093] Solder pads 3, each of the main grid lines 2 is provided with a plurality of the solder pads 3, and the solder pads 3 are fixedly and electrically connected to the main grid lines 2;
[0094] A plurality of fine grid lines 4, wherein the fine grid lines 4 are arranged on the solar cell body, and are connected to different main grid lines 2 through the fine grid lines 4, and the fine grid lines 4 are arranged parallel to each other, and the fine grid lines 4 are perpendicular to the main grid lines 2;
[0095] A plurality of conductive connection points 5, wherein the conductive connection points 5 are arranged between the thin grid lines 4 and the solar cell body,
[0096] The main grid line 2 is made of aluminum, the fine grid line 4 is made of aluminum, and the conductive connection point 5 is made of silver.
[0097] The solar cell body 1 has a length of 183.75 mm, a width of 182 mm, and a thickness of 100 μm.
[0098] The conductive connection points 5 are not completely covered by the fine grid lines 4 .
[0099] The plurality of conductive connection points 5 are distributed in a rectangular array on the solar cell body.
[0100] The width of the main grid line 2 is 50 μm, and the width of the fine grid line 4 is 30 μm.
[0101] The conductive connection point 5 is in the shape of a rectangle, with a length of 60 μm and a width of 50 μm;
[0102] The distance between adjacent main grid lines 2 is 30 mm, and the distance between adjacent thin grid lines 4 is 1 mm.
[0103] The distance between adjacent conductive connection points 5 is 35 mm.
[0104] Comparative Example
[0105] This comparative example provides a low-cost solar cell, the low-cost solar cell comprising: a solar cell body, and an electrode disposed on the solar cell body, the electrode comprising:
[0106] A plurality of main grid lines, wherein the main grid lines are arranged on the solar cell body and are arranged parallel to each other;
[0107] Solder pads, each of the main grid lines is provided with a plurality of the solder pads, and the solder pads are fixedly and electrically connected to the main grid lines;
[0108] A plurality of fine grid lines, wherein the fine grid lines are arranged on the solar cell body and are connected to the main grid lines through the fine grid lines, and the fine grid lines are arranged parallel to each other and are perpendicular to the main grid lines.
[0109] Wherein, the material of the main grid line is silver, and the material of the fine grid line is silver.
[0110] The solar cell body has a length of 183.75 mm, a width of 182 mm, and a thickness of 135 μm.
[0111] The width of the main grid line is 45 μm, and the width of the fine grid line is 20 μm.
[0112] The distance between adjacent main grid lines is 30 mm, and the distance between adjacent fine grid lines is 1.5 mm.
[0113] The amount of raw materials used for the grid lines of the low-cost solar cells provided in Example 1, Example 2, and the comparative example is statistically analyzed, and the results are shown in Table 1.
[0114] Silver paste dosage (mg) Silver paste price (yuan / Kg) Aluminum paste dosage (mg) Aluminum paste price (yuan / kg) Slurry cost (yuan) Example 1 18 6546 96 6304 0.72 Example 2 16 6546 100 6304 0.74 Comparative Example 117 6546 0 6304 0.77
[0115] Table 1
[0116] It can be seen from Table 1 that the slurry costs of Example 1 and Example 2 are significantly lower than those of the comparative example. The only difference between Example 1 and the comparative example is that the comparative example does not have a conductive connection point, and the material of the gate line is silver. This shows that under the condition that other conditions remain unchanged, the technical solution of replacing the gate line material with aluminum and adding a conductive connection point can effectively reduce the slurry cost.
[0117] After testing with an IV tester, the ETA (photoelectric conversion efficiency), Uoc (open circuit voltage), Isc (short circuit current), and FF (fill factor) of the low-cost solar cells provided in Example 1, Example 2, and the comparative example are shown in Table 2.
[0118] Eta(%) Uoc(mV) Isc(mA) FF(%) Example 1 25.62 718.5 14.0493 84.70 Example 2 25.66 719.2 14.0612 84.76 Comparative Example 25.61 718.8 14.0220 84.63
[0119] Table 2
[0120] It can be seen from Table 2 that the electrical properties of Example 1, Example 2, and the comparative example are basically the same, with very little difference, wherein the difference between Example 1 and the comparative example is only that the comparative example does not have a conductive connection point, and the material of the grid line is silver. This shows that under the condition that other conditions remain unchanged, the technical solution of replacing the grid line material with aluminum and adding a conductive connection point will not affect the electrical performance of the solar cell.
[0121] In summary, it can be considered that, under the condition that other conditions remain unchanged, the technical solution of replacing the grid line material with aluminum and adding conductive connection points can reduce the slurry cost while maintaining the electrical performance of the solar cell unchanged.
[0122] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.
[0123] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "including", "comprising", etc. refer to "including but not limited to". Moreover, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "including..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. For the association relationship of more than three associated objects described by "and / or", it means that any one of these three associated objects can exist alone, or any at least two of them exist at the same time. For example, for A, and / or B, and / or C, it can be represented that any one of A, B, and C exists alone, or any two of them exist at the same time, or three of them exist at the same time. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single (individual) or plural (individual). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, wherein a, b, and c can be single or multiple, respectively.
[0124] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.
Claims
1. A low-cost solar cell, characterized in that: The low-cost solar cell comprises: a solar cell body, and an electrode arranged on the solar cell body, wherein the electrode comprises: A plurality of main grid lines, wherein the main grid lines are arranged on the solar cell body and are arranged parallel to each other; Solder pads, each of the main grid lines is provided with a plurality of the solder pads, and the solder pads are fixedly and electrically connected to the main grid lines; A plurality of fine grid lines, wherein the fine grid lines are arranged on the solar cell body and are connected to different main grid lines through the fine grid lines, and the fine grid lines are arranged in parallel with each other and are perpendicular to the main grid lines; A plurality of conductive connection points, wherein the conductive connection points are arranged between the thin grid lines and the solar cell body, Wherein, the material of the main grid line is aluminum, the material of the fine grid line is aluminum, and the material of the conductive connection point is silver.
2. The low-cost solar cell according to claim 1, characterized in that: The conductive connection points are not completely covered by the fine grid lines.
3. The low-cost solar cell according to claim 2, characterized in that: A plurality of the conductive connection points are distributed in a rectangular array on the solar cell body.
4. The low-cost solar cell according to claim 2, characterized in that: The width of the main grid line is 40 to 60 μm; and / or, The width of the fine gate line is 15-30 μm.
5. The low-cost solar cell according to claim 4, characterized in that: The conductive connection point is in the shape of a rectangle, with a length of 50 to 70 μm and a width of 45 to 60 μm.
6. The low-cost solar cell according to claim 4, characterized in that: The conductive connection point is in the shape of an ellipse, with a major axis length of 60 to 140 μm and a minor axis length of 40 to 110 μm.
7. The low-cost solar cell according to claim 4, characterized in that: The distance between adjacent main grid lines is 25 to 35 mm; and / or, The distance between adjacent fine grid lines is 0.75-1.5 mm.
8. The low-cost solar cell according to claim 4, characterized in that: The distance between adjacent conductive connection points is 30-40 mm.
9. A solar cell group, characterized in that: The solar cell array comprises: A low-cost solar cell as claimed in any one of claims 1 to 8; A welding ribbon is welded to both the main grid lines and the welding pads of several low-cost solar cells.