WO2014187111A1

WO2014187111A1 - Front gate line of solar battery piece, and solar battery piece

Info

Publication number: WO2014187111A1
Application number: PCT/CN2013/089074
Authority: WO
Inventors: 王立建; 蔡岳峯
Original assignee: 浙江昱辉阳光能源江苏有限公司
Priority date: 2013-05-24
Filing date: 2013-12-11
Publication date: 2014-11-27
Also published as: CN203250754U

Abstract

Provided are a front gate line of a solar battery piece, and a solar battery piece. The front gate line comprises at least four main gate lines which are parallel to each other, wherein at least one main gate line among the main gate lines comprises a first connecting part (21) and a second connecting part (22), which are alternately connected end to end, and the width of the first connecting part (21) is greater than that of the second connecting part (22). By adding the number of the main gate lines in the front gate line to at least four, the series resistance of the solar battery piece is reduced; the metal slurry used for making a single main gate line is saved, and it is realized that the series resistance of the battery piece is reduced on the premise of a low production cost, thus improving the conversion efficiency of the battery piece.

Description

The front gate line and the solar cell of the solar cell sheet. The application is submitted to the Chinese Patent Office on May 24, 2013, and the application number is 201320295973.3. The utility model name is "a solar cell front grid and solar cell". The priority of the Chinese Patent Application, the entire disclosure of which is incorporated herein by reference. Technical field

The present invention relates to the field of solar cell technology, and more particularly to a front gate line and a solar cell sheet of a solar cell sheet.

Background technique

A solar cell is a semiconductor device that directly converts the solar light energy into electrical energy. Because it is a green product, it does not cause environmental pollution, and it uses renewable resources. Therefore, in today's energy shortage, solar cells have broad prospects for development.

Common solar cells are from front to back: front gate line, passivation anti-reflection film, doped layer, silicon substrate and back electrode. The structure of the front gate line is shown in Figure 1, including three mutual The parallel main gate lines 11 and the plurality of mutually parallel sub-gate lines 12, the main gate lines 11 and the sub-gate lines 12 are perpendicular to each other. The width of the main grid line 11 is generally set to be substantially the same as the width of the electrode. The purpose is to connect the plurality of solar cells in series by soldering the electrodes on the main grid line to realize the packaging of the solar cell sheets.

Conversion efficiency is an important indicator to measure the ability of a solar cell to convert light energy into electrical energy. Increasing the number of main gate lines 11 in the front gate line can reduce the series resistance of the cell, thereby improving the photoelectric conversion efficiency of the cell. However, the front gate line of the solar cell is generally formed of an expensive silver paste, and increasing the number of the main gate lines 11 increases the manufacturing cost of the solar cell sheet. Summary of the invention

The invention provides a front grid line and a solar cell sheet of a solar cell sheet, so as to reduce the series resistance of the solar cell sheet and improve the conversion efficiency of the solar cell sheet under the premise of low production cost.

To achieve the above object, the present invention provides the following technical solutions:

A front gate line of a solar cell panel, the front gate line includes at least four main gate lines parallel to each other, and at least one of the main gate lines includes first and second connecting portions alternately connected end to end The second connecting portion has a width greater than a width of the second connecting portion.

Preferably, the width of the first connecting portion ranges from 0.3 mm to 2 mm, including the end point value. Preferably, the first connecting portion has a length ranging from 3 mm to 15 mm, inclusive. Preferably, the number of the first connecting portions included in the same main gate line of the main gate line having the first connecting portion and the second connecting portion ranges from 3 to 10, inclusive.

Preferably, the first connection portion included in the same main gate line of the main gate line having the first connection portion and the second connection portion is equally spaced.

Preferably, the first connecting portions included in the same main gate line of the main gate lines having the first connecting portion and the second connecting portion are not equally spaced.

Preferably, the width of the second connecting portion ranges from 0.1 mm to 0.4 mm, including the end point value.

Preferably, the number of the second connecting portions included in the same main gate line in the main gate line having the first connecting portion and the second connecting portion ranges from 3 to 10, inclusive.

Preferably, the second connection portion included in the same main gate line of the main gate line having the first connection portion and the second connection portion is equally spaced.

Preferably, the second connecting portions included in the same main gate line of the main gate lines having the first connecting portion and the second connecting portion are not equally spaced.

Preferably, the number of the main gate lines is five.

Preferably, the main grid lines are equally spaced. Preferably, the main gate lines are not equally spaced.

Preferably, the front gate line further includes a plurality of sub-gate lines, the widths of the plurality of sub-gate lines being varied and being the widest at a portion intersecting the main gate lines. In this scheme, since the width of the sub-gate line is the widest at the portion intersecting the main gate line, the current collecting ability of the main gate line can be improved, and the loss of current during transmission is reduced. In this way, the series resistance can be further reduced, thereby increasing the power output of the battery.

Preferably, the plurality of sub-gate lines each have a width that gradually changes to 'J' in a direction away from the main gate line, and are symmetrically arranged with respect to the main gate line.

Preferably, the plurality of sub-gate lines are configured in one of the following configurations: a substantially parallel line, or a concentric circle, a concentric arc, a concentric ellipse, or a center centered on the main grid line and falling in the same Triangles, rectangles, and polygons on the main grid.

Preferably, the plurality of sub-gate lines constitute one sub-gate line unit such that at least one of the sub-gate line units and the at least four main gate lines form the front gate line.

Preferably, the front gate line includes a plurality of the sub-gate line units, and the plurality of the sub-gate line units have the same configuration or different configurations.

Preferably, the plurality of sub-gate lines of the at least one of the sub-gate line units are configured in one of the following configurations: a substantially parallel line, or a concentric circle, a concentric arc, a concentric ellipse whose center falls on the main grid line , or a triangle, a rectangle, or a polygon having the same center and falling on the main grid.

Preferably, the spacing between adjacent ones of the plurality of sub-gate lines is equal.

Preferably, the width of each of the plurality of sub-gate lines varies within a range of 0.04 mm to 0.2 mm.

The invention also provides a solar cell sheet, the solar cell sheet comprising: a silicon wafer substrate;

a doped layer covering the front side of the silicon wafer substrate;

a passivation anti-reflection film covering a side of the doped layer facing away from the substrate of the silicon wafer; a front gate line disposed on a side of the passivation anti-reflection film facing away from the substrate of the silicon wafer, the front gate line being a front gate line of the solar cell sheet according to any of the above; A back electrode disposed on the back surface of the silicon wafer substrate.

Compared with the prior art, the technical solution provided by the present invention has at least the following advantages: The front gate line and the solar cell sheet of the solar cell sheet provided by the present invention increase the number of main gate lines in the front gate line to at least 4 Strip, reducing the lateral resistance of the current transmission, reducing the series resistance of the solar cell; and at least one of the main gate lines alternately appears with the first connection portion and the second connection portion, connected end to end, and the width of the first connection portion The structure of the width of the first connecting portion is substantially the same as the width of the main gate line in the prior art, which saves the metal paste used for fabricating a single main gate line, compared with the prior art. The production cost of the grid of the grid line is not increased much. When a plurality of main gate lines are used in the above structure, the metal paste used for the entire main gate line can be realized without increasing, but will be reduced. That is to say, the technical solution provided by the invention realizes reducing the series resistance of the battery sheet under the premise of low production cost, thereby improving the rotation of the battery sheet. Change efficiency.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description It is merely some embodiments of the present invention, and those skilled in the art can obtain other drawings according to the drawings without any creative work.

1 is a structural view of a front gate line of a prior art solar cell;

2 is a structural diagram of a front gate line of a solar cell according to Embodiment 1 of the present invention;

3 is a structural diagram of another solar cell front gate line according to Embodiment 1 of the present invention;

4 is a cross-sectional view showing a solar cell sheet according to a second embodiment of the present invention; and FIG. 5 is a cross-sectional view showing a solar cell sheet according to a third embodiment of the present invention. detailed description

The above described objects, features and advantages of the present invention will become more apparent from the aspects of the appended claims.

In the following description, numerous specific details are set forth in order to provide a full understanding of the invention, but the invention may be practiced in other embodiments than those described herein, and those skilled in the art can A similar promotion is made, and thus the present invention is not limited by the specific embodiments disclosed below.

The present invention will be described in detail with reference to the accompanying drawings. When the embodiments of the present invention are described in detail, for the convenience of description, the sectional view of the structure of the device will not be partially enlarged, and the schematic diagram is only an example, which should not be limited herein. The scope of protection of the present invention. In addition, the actual three-dimensional dimensions of length, width and depth should be included in the actual production. Embodiment 1

The present invention provides a front side gate line of a solar cell sheet, the front side gate line including at least four mutually parallel main gate lines, and at least one of the main gate lines includes first and second ends connected alternately a connecting portion and a second connecting portion, wherein a width of the first connecting portion is greater than a width of the second connecting portion.

Since the solar cell piece needs to be connected in series with the main grid line by welding, in order to increase the contact area between the electrode and the main gate line to reduce the ohmic contact resistance of the two, the width of the main gate line is generally set to be the width of the electrode. Consistent. There is a difference between the material forming the main gate line material and the electrode, so that the current is transmitted from the main gate line to the electrode to have resistance, that is, the series resistance of the solar cell. The cross-sectional area of current transmission is a direct factor affecting the size of the resistor. The larger the cross-sectional area, the smaller the resistance. The main gate line of the front gate line of a conventional crystalline silicon solar cell is three, resulting in a cross-sectional area not being transmitted during current transmission. Very large, so the series resistance is large. The series resistance and production cost are two mutual checks and balances. If the number of main gate lines is increased to increase the cross-sectional area in order to reduce the series resistance, the main gate line formed by the expensive metal silver paste will directly cause electricity. The production cost of the pool is too high.

The front gate line provided in this embodiment increases the number of main gate lines, and increases the conventional three main gate lines to at least four, thereby increasing the cross-sectional area of current transmission and reducing the series resistance of the solar cell. , thereby improving the conversion efficiency of the battery sheet and reducing the power loss of the package after the battery package.

And, at least one main gate line of the main gate line is disposed as a structure in which a first connecting portion having a relatively large width and a second connecting portion having a narrow width appear alternately and end to end, and the width of the first connecting portion is different from that in the prior art. The width of the main gate line is basically the same. From the point of the amount of silver paste of a single main grid line, the amount of silver paste of the main grid line which is thicker than the width of the prior art is significantly reduced, and the cost is reduced. The solar cell sheet using the front gate line structure provided by the embodiment can reduce the series resistance of the cell sheet under the premise of low cost.

According to the actual situation, the number of main gate lines of the structure in which the first connection portion having a relatively thick width and the second connection portion having a small width appear alternately and end to end may be selected according to actual conditions, so when there are a plurality of main gate lines When the above structure is adopted, the embodiment can realize that the total amount of the silver paste on the front side of the cell sheet is less than the total amount of the silver paste in the front side of the grid line including the three main gate lines in the prior art, thereby reducing the production cost of the cell sheet. At the same time, reduce the series resistance. In the present embodiment, it is preferable to adopt the above structure for all the main gate lines of the single-piece battery sheet.

It should be noted that, considering the shielding effect of the main gate line on the front surface of the battery sheet, the light energy absorbed by the battery sheet is decreased. In this embodiment, the number of the main grid lines of the single-chip battery needs to be balanced according to the series resistance and the shielding area. The relationship is properly selected.

The first connecting portion is a wider portion of the main gate line, and is mainly used for welding with the electrode except for collecting current, so the width is set to be substantially the same as the width of the electrode, and the width of the first connecting portion is preferably It is 0.3mm ~ 2mm, including the endpoint value.

The length of the first connecting portion needs to be appropriately selected. If it is too long, the effect of saving the slurry and reducing the cost is not good. If it is too short, the contact resistance between the main gate line and the welding rod may be increased, so the first connecting portion The length is preferably from 3 mm to 15 mm, inclusive.

According to the length of each of the selected first connecting portion and the second connecting portion, The number of the first connecting portions included in the same main gate line in the main gate lines of the first connecting portion and the second connecting portion is preferably in the range of 3 to 10, inclusive.

The first connecting portion included in the same main gate line of the main gate line having the first connecting portion and the second connecting portion may be equally spaced or may be distributed at an equal interval; in order to optimize the performance of the solar cell sheet More stable, the first connecting portions included in the same main gate line of the main gate lines having the first connecting portion and the second connecting portion are preferably equally spaced.

The second connecting portion is a thinner portion of the main gate line. In addition to collecting current, it is mainly used to save slurry. Therefore, the second connecting portion preferably has a width ranging from 0.1 mm to 0.4 mm, inclusive.

The length and distribution of the first connecting portion determine the length and distribution of the second connecting portion. If the second connecting portion is too long, although the slurry can be saved and the cost can be reduced, the battery is mostly thin. The contact connection of the second connecting portion with the electrode may increase the contact resistance between the main gate line and the electrode, and if it is too short, the slurry saved may be small.

The number of the second connection portions included in the same main gate line in the main gate line having the first connection portion and the second connection portion ranges from 3 to 10, inclusive.

The second connecting portion included in the same main gate line of the main gate line having the first connecting portion and the second connecting portion may be equally spaced or may be distributed at an equal interval; in order to optimize the performance of the solar cell sheet More stable, the second connecting portions included in the same main gate line of the main gate lines having the first connecting portion and the second connecting portion are preferably equally spaced.

In this embodiment, it is more preferable to set the number of the main gate lines to five, and the cell series resistance is lower with respect to the battery sheet having the front structure of the four main gate lines, so that the loss of the battery is smaller.

Moreover, this embodiment does not limit the distribution of the main gate lines on the front side of the battery, and the main gate lines may be equally spaced or distributed at equal intervals; in order to balance the performance and appearance of the solar cell sheets, the single-gate solar energy of the main grid The lines are preferably equally spaced.

The front gate line provided by the embodiment is specifically described below with reference to FIG. 2. The front gate line of the cell includes four main gate lines which are parallel and equally spaced, and a plurality of parallel lines and the like. The sub-gate lines of the pitch distribution, the main gate lines and the sub-gate lines are perpendicular to each other. Each of the main grid lines includes eight first connecting portions 21 of equal width and equal length and nine second connecting portions 22 of equal width and equal length, wherein the first connecting portion 21 has a length of 7 mm and a width of 1.4 mm. The width of the second connecting portion 22 is 0.2 mm, and the width of each of the sub-gate lines is 0.04 mm. The series resistance of the solar cell monolith using the above structure is 1.9 milliohms, which is 24% lower than the prior art monolithic series resistance of 2.5 milliohms.

As shown in FIG. 3, the front gate line of another structure provided in this embodiment includes four main gate lines which are parallel and equally spaced, and a plurality of sub-gate lines which are parallel and equally spaced. The gate line and the sub-gate line are perpendicular to each other. Each of the main grid lines includes six first connecting portions 31 of equal width and equal length and seven second connecting portions 32 of equal width and equal length, wherein the first connecting portion 31 has a length of 12 mm and a width of 0.45 mm. The width of the second connecting portion 32 is 0.15 mm, and the width of each of the sub-gate lines is 0.045 mm. The series resistance of the solar cell monolith having the above structure is 1.8 milliohms, which is 28% lower than that of the prior art single chip series resistance of 2.5 milliohms.

In addition, in order to save the slurry, the inventors considered setting the main gate line to a hollow structure, such as: the width of the single main gate line as a whole is constant, but the main gate line is a segmented structure in which the solid segment and the hollow segment alternately appear, although Such a structure can reduce the amount of slurry used, but there is almost no contact between the hollow portion and the electrode; in this embodiment, the width of the first connecting portion is substantially the same as the width of the electrode, so that it can completely contact the electrode, and the second The connecting portion is a solid structure, and can form a certain area of contact with the electrode during sintering. It can be seen that the contact area between the main gate line and the electrode in the embodiment is larger than the contact area between the main gate line and the electrode of the hollow structure. In the case where the welding stress is constant, the stress per unit area of the main grid line in this embodiment is smaller, and the probability of breakage of the battery sheet is reduced.

Moreover, in order to save the slurry, the inventors have also considered to design both ends or a section of the main gate line as a structure with a tip end, and the main gate line of such a structure is extremely susceptible to breakage at the portion having the tip end, and the reason is the above-described hollow structure. The reason why the main grid line is easily broken is basically the same, since the contact surface of the tip end portion and the electrode strip is positively small, the stress is large; in this embodiment, the end portion of the main grid line is The straight structure has the same width as the width of the first connecting portion or the second connecting portion, so that the contact area with the electrode is large, and the chipping rate of the battery sheet is lowered. Embodiment 2

Based on the first embodiment, the embodiment provides a solar cell sheet. As shown in FIG. 4, the solar cell sheet includes:

Silicon wafer substrate 41 ;

The silicon substrate 41 may be N-type or P-type, the polycrystalline silicon solar cell is usually P-type, and the monocrystalline silicon solar cell is usually N-shaped.

a doped layer 42 covering the front surface of the silicon wafer substrate;

The doping type of the doping layer 42 corresponds to the silicon wafer substrate 41. If the silicon wafer substrate 41 is P-type, N-type phosphorus doping is required to form an N-type phosphorus doping layer, if the silicon wafer substrate 41 is N-type. Then, P-type boron doping is required to form a P-type boron doped layer.

Generally, a doping layer 42 is formed by a diffusion process, and a PN junction is formed at the interface between the doping layer 42 and the silicon wafer substrate 41. The solar cell receives the light energy, and the external circuit of the cell is under the action of the built-in electric field generated by the PN junction. There will be current flowing.

Passivation anti-reflection film covering the doped layer 42 away from the side of the silicon wafer substrate 41

44;

A passivation anti-reflection film 44 is deposited on the front side of the cell sheet by a PECVD (Plasma Enhanced Chemical Vapor Deposition) process. The main material of the passivation anti-reflection film is silicon nitride, which can enhance solar energy. The absorption of light by the battery sheet effectively improves the photoelectric conversion efficiency of the battery. The passivation anti-reflection film 44 contains a large amount of H atoms at the same time. During the film deposition process, the H atoms reach the surface and inside of the cell sheet, and are combined with the cells in the cell sheet. The dangling key acts as a passivation and a body passivation to reduce the recombination of carriers.

The front gate line 43 is disposed on the side of the passivation anti-reflection film 44 facing away from the silicon wafer substrate 41 (only the main gate line is shown), and the front gate line 43 is the solar power described in the first embodiment. The front grid line of the pool piece;

Screen printing technology is commonly used to print metal silver paste on the front side of the silicon wafer to form a front gate line.

43. The structure of the front gate line 43 has been described in detail in Embodiment 1, and will not be described again here.

A back electrode 45 is provided on the back surface of the silicon wafer substrate 41.

The back electrode 45 can also be formed by a screen printing technique. The back surface electrode 45 includes a back surface field and a back surface gate line. The back surface field is generally formed of an aluminum paste, and the back gate line is formed of a silver paste. The back surface field is mainly used. In addition to collecting current, the back gate line also has a welding electrode for the solar cell to be packaged in series.

In the solar cell sheet provided in this embodiment, the main gate lines in the front gate lines are at least four, and at least one main gate line alternates between the thicker first connecting portion and the thinner second connecting portion, and the first end The connected structure increases the cross-sectional area of the current flow under the premise of low production cost, reduces the series resistance of the cell, improves the conversion efficiency of the solar cell, and reduces the power loss. Embodiment 3

In this section, the differences between the present embodiment and the other embodiments described above are mainly described, and the same points as those of the other embodiments described above will not be repeatedly described.

In this embodiment, in addition to the above-described main gate line, the front gate line according to the present invention may further include a plurality of sub-gate lines, wherein the widths of the plurality of sub-gate lines are varied and intersect with the main gate line The part is the widest. In this configuration, since the width of the sub-gate line is the widest at the portion intersecting the main gate line, the current collecting ability of the main gate line can be improved, and the current loss during transmission is reduced. In this way, the series resistance can be further reduced, thereby increasing the power output of the battery.

The width of the sub-gate line gradually becomes smaller in a direction away from the main gate line. Preferably, the width-changing sub-gate lines described above may be disposed to be symmetrical about the main gate line. Referring to FIGS. 2 and 3, the plurality of sub-gate lines having the varying widths may be arranged in substantially parallel straight lines and substantially perpendicular to the main gate lines. In the illustrated embodiment, since the sub-gate lines are straight lines parallel to each other, the sub-gate The lines may extend through the plurality of main gate lines, or even all of the main gate lines, in a direction perpendicular to the main gate lines. However, it can be understood that the above-described substantially parallel-arranged width-changing sub-gate lines may be at an angle to the main gate lines in addition to being perpendicular to the main gate lines. In addition, the width-changing sub-gate lines may be formed in a curved shape such as a wave shape or a sawtooth shape. Referring to Figure 5, another configuration of the sub-gate lines is shown. In this example configuration, a plurality of sub-gate lines are arranged in a concentric circle, wherein the center of the circle falls on the main gate line; the width of each of the sub-gate lines is varied and is the widest at the portion intersecting the main gate line . It is understood that the illustrated embodiments are for illustrative purposes only and are not intended to limit the invention. Although the sub-gate lines shown in FIGS. 2 and 3 are parallel straight lines, the sub-gate lines of the concentric circle configuration are shown in FIG. 5, however, it will be understood that the sub-gate lines may be of any other suitable configuration. For example, an arc, an ellipse, a triangle, a rectangle, or a regular polygon.

Further, referring to Fig. 5, a plurality of width-changing sub-gate lines constructed in a concentric circular shape may be formed as one sub-gate line unit. A plurality of such sub-gate line cells are continuously and repeatedly arranged, and a front gate line as shown in Fig. 5 is formed with a plurality of main gate lines. In other words, the front gate line may include a plurality of sub-gate line cells, and each of the sub-gate line cells includes a plurality of sub-gate lines configured in a certain configuration. In the embodiment shown in Fig. 5, the plurality of sub-gate line cells have the same configuration, i.e., the plurality of sub-gate lines in each of the sub-gate line cells are arranged in a concentric circular configuration. However, it can be understood that in the case where the front gate line includes a plurality of sub-gate line units, these sub-gate line units may have the same configuration or may have different configurations. In this configuration, since there are a plurality of sub-gate line units, the size of the sub-gate lines can be reduced, thereby facilitating processing and mounting. This embodiment is particularly suitable for fabricating large-sized front gate lines and can be adapted to the configuration of various front gate lines (e.g., the number of main gate lines). It should be understood that the number of sub-gate line units may be one or more depending on the processing and mounting conditions of the front side gate lines and the like.

As is clear from Fig. 5, the portion of the sub-gate line that intersects the main gate line is the thickest (widest), and the portion that is farthest from the main gate line is the thinnest. The width of the sub-gate lines is varied, preferably uniformly and gradually, thereby making the performance of the cell sheet more stable. Preferably, each sub-gate line The width varies from 0.04 mm to 0.2 mm. The widths at the corresponding portions of the sub-gate lines may be the same or may be different.

The spacing between adjacent sub-gate lines may be equal or may be unequal.

By using the front gate line of this embodiment, the monolithic series resistance of the solar cell can be 1.5 milliohms, which is reduced compared to the 2.5 milliohm series resistance of the prior art.

40%.

Although the invention has been disclosed above in the preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention by using the methods and technical contents disclosed above, or modify the equivalent implementation of equivalent changes without departing from the scope of the technical solutions of the present invention. example. Therefore, any modifications, equivalent changes, and modifications of the invention may be made without departing from the scope of the invention.

Claims

Rights request

1. A front-side grid line of a solar cell, characterized in that the front-side grid line includes at least four mutually parallel main grid lines, and at least one of the main grid lines includes alternating end-to-end connected main grid lines. The first connection part and the second connection part, the width of the first connection part is greater than the width of the second connection part.

2. The front grid line of the solar cell according to claim 1, characterized in that the width of the first connection part ranges from 0.3mm to 2mm, including the endpoint value.

3. The front grid line of the solar cell according to claim 1, wherein the length of the first connection part ranges from 3mm to 15mm, including endpoints.

4. The front grid line of the solar cell according to claim 1, characterized in that, among the main grid lines having the first connecting portion and the second connecting portion, the first connecting portion is included in the same main grid line. The quantity range is 3 ~ 10, including endpoint values.

5. The front grid line of the solar cell according to claim 4, characterized in that, among the main grid lines having the first connecting portion and the second connecting portion, the first connecting portion is included in the same main grid line. equally spaced distribution.

6. The front grid line of the solar cell according to claim 4, characterized in that, among the main grid lines having the first connecting portion and the second connecting portion, the first connecting portion is included in the same main grid line. Non-equally spaced distribution.

7. The front grid line of the solar cell according to claim 1, wherein the width of the second connection part ranges from 0.1mm to 0.4mm, including endpoint values.

8. The front grid line of the solar cell according to claim 1, characterized in that, among the main grid lines having the first connecting portion and the second connecting portion, the second connecting portion is included in the same main grid line. The quantity range is 3 ~ 10, including endpoint values.

9. The front grid line of the solar cell according to claim 8, characterized in that, among the main grid lines having the first connecting portion and the second connecting portion, the second connecting portion is included in the same main grid line. equally spaced distribution.

10. The front-side grid line of a solar cell according to claim 8, wherein the same main grid line among the main grid lines having the first connection portion and the second connection portion includes a third main grid line. The two connecting parts are distributed at non-equal intervals.

11. The front grid line of the solar cell according to claim 1, characterized in that the number of the main grid lines is 5.

12. The front grid lines of the solar cell according to claim 1, wherein the main grid lines are distributed at equal intervals.

13. The front grid lines of the solar cell sheet according to claim 1, wherein the main grid lines are distributed at non-equal intervals.

14. The front grid line of the solar cell according to any one of claims 1 to 13, characterized in that, the front grid line further includes a plurality of auxiliary grid lines, and the width of the plurality of auxiliary grid lines is varies and is widest at the portion where it intersects the main grid lines.

15. The front-side grid line of a solar cell according to claim 14, wherein each of the plurality of auxiliary grid lines has a width that gradually becomes smaller in a direction away from the main grid line, and has a width that gradually decreases with respect to the main grid line. The grid lines are arranged symmetrically.

16. The front grid line of the solar cell according to claim 14 or 15, characterized in that the plurality of auxiliary grid lines are configured in one of the following configurations: substantially parallel lines, or the center of the circle falls on the main grid line Concentric circles, concentric arcs, concentric ellipses, or triangles, rectangles, polygons with the same center and falling on the main grid line.

17. The front-side grid line of the solar cell according to claim 14 or 15, characterized in that the plurality of sub-grid lines constitute a sub-grid line unit, so that at least one of the sub-grid line units is connected to the at least one sub-grid line unit. Four main grid lines form the front grid lines.

18. The front grid line of a solar cell according to claim 17, wherein the front grid line includes a plurality of sub grid line units, and the plurality of sub grid line units have the same structure or different structure.

19. The front grid line of the solar cell according to claim 17 or 18, characterized in that at least one of the plurality of sub grid lines in the sub grid unit is configured in one of the following structures: substantially parallel lines, Either concentric circles, concentric arcs, or concentric ellipses whose centers fall on the main grid line, or triangles, rectangles, or polygons with the same center that fall on the main grid line.

20. The front grid of the solar cell according to any one of claims 14 to 19 line, characterized in that the spacing between adjacent sub-grid lines among the plurality of sub-grid lines is equal.

21. The front-side grid line of a solar cell according to any one of claims 14 to 20, wherein the width of each of the plurality of sub-grid lines varies within a range of 0.04 mm to 0.2 mm. .

22. A solar cell, characterized in that, the solar cell includes: a silicon wafer substrate;

A doped layer covering the front surface of the silicon wafer substrate;

A passivation anti-reflection film covering the side of the doped layer facing away from the silicon wafer base; a front gate line provided on the side of the passivation anti-reflection film facing away from the silicon wafer base, and the front side gate line is The front grid line of the solar cell according to any one of claims 1 to 21; a back electrode provided on the back side of the silicon chip base.