CN213583811U - Efficient high-reliability PERC solar cell and front electrode thereof - Google Patents

Abstract

The utility model discloses a high-efficient high reliability PERC solar cell and positive electrode thereof belongs to solar cell technical field. The utility model discloses a solar cell's positive electrode, its main bars include thin main bars and are located thin main bars interval distribution's solder joint, and thin main bars between the adjacent solder joint is including the thin main bars of the straight line of connecting two solder joints to and be located the thin main bars of lateral part of the thin main bars both sides of straight line. Adopt the technical scheme of the utility model when promoting battery conversion efficiency, effectively improve its quality and reliability.

Description

Efficient high-reliability PERC solar cell and front electrode thereof

Technical Field

The utility model belongs to the technical field of solar cell, more specifically say, relate to a high-efficient, high reliability PERC solar cell and positive electrode thereof.

Background

A crystalline silicon solar cell is a device for converting light energy into electric energy using a photovoltaic effect of a PN junction, and a PERC cell has been gradually developed into a high-efficiency solar cell product and technology which are mainstream in the market. How to further improve the conversion efficiency of the PERC battery, reduce the conversion efficiency difference with high efficiency batteries such as hjt (heterojunction technology), TOPCon, etc., and maintain the advantage of comprehensive cost performance is a problem that the PERC + technology continuously faces in the future.

Meanwhile, the reliability and durability of the PERC battery assembly are also receiving increasing attention from researchers and customers. Different attenuation phenomena, such as PID effect, LID, LETID, backboard aging cracking, EVA yellowing and the like, all affect the service life of the photovoltaic module. With the continuous development of photovoltaic technology, the shelf life of photovoltaic modules is also extended from the first 5 years to at least 25 years today. Thus, the international renewable energy laboratory evaluates the factory quality of a crystalline silicon component by performing indoor accelerated aging tests (including ISC61215 and UL1703 standards) on the component and closely simulates the long-term reliability of the component over a warranty period under outdoor operating environmental conditions. From the long-term development point of view, high-efficiency and high-reliability batteries and assemblies still remain the main direction of future development of the photovoltaic industry.

The metallization of the front electrode is one of the important links for improving the efficiency and reducing the cost of the solar cell. The MBB (Multi-Busbar) batteries (the number of the main grids is more than or equal to 9) can greatly improve the battery efficiency on one hand, and can effectively reduce the consumption of silver paste on the other hand, so that the market share of the MBB technology is gradually improved, and the MBB technology is further developed towards the technology without the main grids (Busbar-free). At present, in order to ensure the problems of assembly reliability, welding precision, tension and the like, an MBB pattern (figure 1) design generally designs a welding point 3-1, a thin main grid 3-2 and an edge fishfork thin main grid 3-3 in a main grid area. In the process of welding the assembly, molten tin in the welding strip and silver paste on the main grid form silver-tin alloy at high temperature to realize metal connection. Wherein the tension is mainly provided by welding between the welding points on the main grid and the welding strips. And the thin main grid is less in silver paste, so that resistance is easy to increase after welding, and current collection of partial areas is affected. Meanwhile, the width of the thin main grid is obviously smaller than that of the welding strip, and the welding strip inevitably has certain alignment deviation in the welding process, so that the welding strip is easy to weld with the auxiliary grid which is vertically intersected with the main grid in the thin main grid area, and the auxiliary grid is easy to break or partially break at the welding position at the moment, so that the EL display broken line after welding is caused. Finally, after long-term environmental aging in the actual use process, the resistance of the area is easy to increase due to small adhesive force or fracture, and finally, the generated energy is continuously reduced, so that the quality and the reliability of the product are influenced.

To the above problem, patent application No. CN201820897922.0 provides a front electrode structure of a multi-main-grid battery and a solar battery, the secondary grid line of the application consists of a straight line segment and a deformation segment, the deformation segment is arranged at the joint of the secondary grid line and the main grid line, the width of the deformation segment gradually widens from the end of the straight line segment to the main grid line, the height of the deformation segment is higher than that of the straight line segment, and the total width of the deformation segment is greater than or equal to the width of a pad. This application is through designing the deformation region in thin main grid and the overlap joint of auxiliary grid region promptly, increases the silver thick liquid total amount in this region to can solve the cracked problem of auxiliary grid line welding among the many main grid battery welding process to a certain extent, but its effect is not very ideal, awaits further improvement.

For another example, the application with chinese patent application No. CN201711417592.7 discloses a novel multi-main-grid cell and a photovoltaic module using the same, in which the main grid line is designed to be a double-line flat elliptical composite shape structure, the end point of each small flat ellipse is a welding reinforcing point, so as to improve the reliability thereof, and when the grid line at one end is bad such as aging and grid breaking, the grid line at the other end can still normally collect current, and the reduction of the overall power generation amount is not affected basically. The main grid line structure of adopting this application has evaded the welding influence of thin main grid and solder strip to a certain extent, but also can reduce the effect that thin main grid and welded connection collected the electric current simultaneously.

Therefore, how to ensure the quality and reliability of the solar cell while improving the conversion efficiency of the solar cell becomes a difficult problem to be continuously solved by the solar cell technology.

SUMMERY OF THE UTILITY MODEL

1. Problems to be solved

An object of the utility model is to solve the problem that current PERC solar cell's quality and reliability remain further to improve, and provide a high-efficient high reliability PERC solar cell and positive electrode thereof. Adopt the technical scheme of the utility model when promoting battery conversion efficiency, effectively improve its quality and reliability.

2. Technical scheme

In order to solve the above problem, the utility model discloses the technical scheme who adopts as follows:

the utility model discloses a solar cell's positive electrode, its main bars include thin main bars and are located thin main bars interval distribution's solder joint, and thin main bars between the adjacent solder joint is including the thin main bars of the straight line of connecting two solder joints to and be located the thin main bars of lateral part of the thin main bars both sides of straight line.

Furthermore, the widths of the straight line thin main grid and the side thin main grid are both 0.06 +/-0.04 mm.

Further, the side fine main grids are divergently arranged relative to the welding spot, and the distance W2 between the two side fine main grids is larger than the width W1 of the welding spot.

Furthermore, the side thin main grids between the adjacent welding points are formed by straight lines or curves, and more preferably, the side thin main grids between the adjacent welding points are straight lines parallel to the straight line thin main grids, and the two ends of the side thin main grids are connected with the welding points through transition connecting lines.

Furthermore, two ends of the straight line thin main grid are respectively connected with the central areas of the two welding points, and the two side thin main grids are symmetrically distributed around the straight line thin main grid.

Furthermore, the auxiliary grid is formed by screen printing without net knots.

Furthermore, two ends of the thin main grid are provided with edge harpoon thin main grids which are designed by adopting an S-shaped curve.

Furthermore, the auxiliary grids are vertically distributed with the main grid, the grid line spacing of the adjacent auxiliary grids is 1.00-1.32mm, and the line width of the auxiliary grids is 10-26 μm.

The utility model discloses a high-efficient high reliability PERC solar cell, include the front electrode.

3. Advantageous effects

Compared with the prior art, the beneficial effects of the utility model are that:

(1) the utility model discloses a solar cell's positive electrode, through carrying out optimal design to the main grid structure, thin main grid design between the adjacent solder joint is for the composite construction that the thin main grid of lateral part combination of the thin main grid of straight line and both sides formed to can prevent that the vice bars from breaking in the main grid welding department on effectively guaranteeing thin main grid and welding the basis that the area is connected and collect the electric current effect, overcome the thin main grid of current positive electrode promptly and weld the influence of taking the welding to battery and subassembly, the quality and the reliability of battery and subassembly have been improved.

(2) The utility model discloses a solar cell's positive electrode, its vice bars adopt no net knot screen printing to form to can eliminate the net knot of warp and weft handing-over in the wire net cloth on the vice bars lines, effectively improve the printing ink permeability of screen printing silver thick liquid and the height and undulation of grid lines 3D appearance. The method can effectively solve the problem that the positions of the network nodes in the main grid area are easy to form lack printing by adopting the non-network-node screen printing technology through the matching of the non-network-node screen printing technology, the optimization of the main grid structure and step-by-step printing, and further ensures the quality and the reliability of the battery product.

(3) The utility model discloses a solar cell' S positive electrode, the thin main bars of edge fish spear at thin main bars both ends adopt S type curve design to can effectively reduce the wire net knot that the wire net moved about freely and quickly steel wire in the main bars district of fish spear more than 80% formed, be favorable to further improving the quality and the reliability of battery product.

(4) The utility model discloses a high-efficient high reliability PERC solar cell carries out the optimal design through the structure to the positive electrode to can effectively overcome the influence to the battery performance when welding of current solar cell positive electrode main grid district and vice grid line do not have the net knot screen printing, realize when effectively promoting PERC solar cell photoelectric conversion efficiency, improve the quality and the reliability of battery.

Drawings

FIG. 1 is a schematic structural diagram of a conventional MBB front electrode (9 main grid);

FIG. 2 is a schematic structural view of a front electrode of a solar cell in example 2;

fig. 3 is a partially enlarged view of the front electrode of the solar cell in example 2;

FIG. 4 is a schematic structural view of a front electrode of a solar cell in example 3;

fig. 5 is a partial enlarged view of the front electrode of the solar cell in example 3;

fig. 6 is a schematic diagram of the sub-grid region of the non-mesh-junction screen printing plate of the present invention;

FIG. 7 is a schematic view of the main grid area of the fish fork of the non-mesh screen of the present invention;

FIG. 8 is a schematic diagram showing a comparison between the conventional linear type and the S-shaped harpoon main grid printing area of the present invention;

FIG. 9 is a step-by-step printing of a master grid pattern;

FIG. 10 is a step-by-step printing of a subgrid pattern;

fig. 11 is a schematic cross-sectional view of a solar cell according to the present invention;

FIG. 12 is a laser SE pattern;

fig. 13 is a partially enlarged view of the laser-doped region of fig. 12.

In the figure: 1. a front electrode; 2. a secondary grid; 3. a main grid; 3-1, welding spots; 3-2, thin main grid; 3-2-1, a side thin main grid; 3-2-2, straight line thin main grid; 3-3, a thin main grid with a fish fork at the edge; 4. a steel wire mesh transverse steel wire; 5. longitudinal steel wires of a steel wire mesh; 6. longitudinal and transverse steel wire nodes; 7. a secondary grid line printing region; 8. a transverse steel wire cut by laser in the secondary grid line printing area; 9-1, printing an area of the linear type harpoon main grid; 9-2, printing an S-shaped harpoon main grid area; 10. a silicon wafer substrate; 11. a front emitter; 11-1, a shallow doped region; 11-2, a heavily doped region; 12. a front passivation and anti-reflection layer; 13. a front surface oxidation layer; 14. a back passivation layer; 15. a back side sub-gate electrode; 16. a sub-gate laser doped region; 16-1, laser spot.

Detailed Description

Aiming at the problem that the main grid structure of the front electrode is optimally designed to be a composite structure consisting of a straight line thin main grid 3-2-2 connected between adjacent welding spots and lateral part thin main grids 3-2-1 positioned at two sides of the straight line thin main grid 3-2-2, thereby preventing the auxiliary grid from being broken at the welding position of the main grid on the basis of effectively ensuring the current collecting effect of the connection of the thin main grid and the welding strip, namely overcoming the influence of the welding of the thin main grid and the welding strip of the existing front electrode on a battery and a component thereof, and improving the quality and the reliability of the battery and the component thereof. The side thin main grid 3-2-1 is divergently arranged relative to the welding point 3-1, the distance W2 between the two side thin main grids 3-2-1 is larger than the width of the welding point 3-1, and the side thin main grid 3-2-1 can be a straight line or a curve, preferably a straight line.

At present, the non-mesh screen printing plate mainly adopts a mode of removing threads by laser cutting, and the method has the advantages of high plate making efficiency, high yield, no need of changing the pattern of a front electrode and the like, and gradually becomes the mainstream. The utility model discloses an adopt no net knot screen printing to form with the vice bars to can eliminate the net knot of warp and weft handing-over in the wire net cloth on the vice bars lines, effectively improve the printing ink permeability of screen printing silver thick liquid and the height fluctuation of grid line lines 3D appearance. However, due to the inherent structural characteristics of the warp and weft in the steel wire mesh cloth, no net knots are formed on the lines of the auxiliary grid, and meanwhile, no net knots are difficult to be formed at the position of the main grid perpendicular to the auxiliary grid and the position of the fish fork of the main grid perpendicular to or obliquely crossing the auxiliary grid under the condition of maintaining the tension and deformation requirements of the steel wire mesh. In the process of mesh-knot-free popularization, due to the matching of silver paste with better plasticity and weaker fluidity, the position of the mesh knot in the main grid area is easy to form a defect, so that under the condition of influencing the current collection effect, the product quality and the reliability are also seriously influenced after long-term environmental aging. And the utility model discloses a carry out optimal design to the structure of main bars, through the optimization cooperation of no net knot technique and main bars structure to can also solve the above-mentioned problem that no net knot technique exists, be favorable to further guaranteeing the quality and the reliability of battery and subassembly thereof.

In order to further understand the technical solution of the present invention, the present invention will be described below with reference to specific embodiments by taking a single crystal P-type silicon wafer as an example.

Example 1

Referring to fig. 2-5, in the front electrode of a solar cell of the present embodiment, the main grid 3 includes a thin main grid 3-2 and solder joints 3-1 spaced apart on the thin main grid 3-2, the thin main grid 3-2 between adjacent solder joints 3-1 includes a straight thin main grid 3-2-2 connecting the two solder joints, and side thin main grids 3-2-1 on both sides of the straight thin main grid 3-2-2.

Example 2

The structure of the front electrode of the solar cell in this embodiment is substantially the same as that of embodiment 1, specifically, in this embodiment, the widths of the linear fine main grid 3-2-2 and the lateral fine main grid 3-2-1 are both 0.06 ± 0.04mm, the lateral fine main grid 3-2-1 is disposed to be outwardly divergent with respect to the solder joint 3-1, the distance W2 between the two lateral fine main grids 3-2-1 is greater than the width of the solder joint 3-1, and the lateral fine main grid 3-2-1 between the adjacent solder joints 3-1 may be formed by a straight line or a curved line.

Example 3

The structure of the front electrode of a solar cell of this embodiment is substantially the same as that of embodiment 2, and further, as shown in fig. 2 and 3, the thin main grid 3-2-1 at the side between adjacent solder joints 3-1 in this embodiment is composed of curves.

Example 4

The structure of the front electrode of the solar cell in this embodiment is substantially the same as that in embodiment 3, and the main differences are that: in the present embodiment, the side fine main grid 3-2-1 between the adjacent welding points 3-1 is composed of straight lines, as shown in fig. 4 and 5, and the effect is best when the side fine main grid 3-2-1 is a straight line parallel to the straight fine main grid 3-2-2, and both ends thereof are connected to the welding point 3-1 through a transition connection line. Further preferably, the two ends of the linear thin main grid 3-2-2 are respectively connected with the central areas of the two welding points 3-1, and the thin main grids 3-2-1 at the two side parts are symmetrically distributed relative to the linear thin main grid 3-2-2, namely the linear thin main grids 3-2-2 between different welding points are collinear.

Example 5

The structure of the front electrode of the solar cell in this embodiment is substantially the same as that in embodiment 4, and the main differences are that: the auxiliary grid 2 in the embodiment is formed by screen printing without net knots, the two ends of the thin main grid 3-2 are provided with edge fishfork thin main grids 3-3, and the edge fishfork thin main grid 3-3 adopts an S-shaped curve design. By combining the figures 7 and 8, the linear type harpoon main grid printing area 9-1 and the S-shaped harpoon main grid printing area 9-2 are compared, and the S-shaped curve design can effectively reduce the net knots formed by the longitudinal and transverse steel wires of the steel wire mesh of the harpoon main grid area by more than 80%, and is beneficial to further improving the quality and reliability of the battery product.

In the method for manufacturing the front electrode, the main grid 3 and the auxiliary grid 2 adopt a step-by-step printing process, specifically, when printing the main grid region, welding points 3-1 and the thin main grid 3-2 are synchronously printed, when printing the auxiliary grid region, the auxiliary grid 2 and the edge fishfork thin main grid 3-3 are synchronously printed, when printing the auxiliary grid region, a non-mesh screen printing plate is adopted, the grid line distance of the adjacent auxiliary grids 2 is 1.00-1.32mm, and the line width of the auxiliary grid 2 is 10-26 μm.

Example 6

With reference to fig. 11, the PERC solar cell of this embodiment includes a back sub-gate electrode 15, a back passivation layer 14, a silicon substrate 10, a front emitter 11, and a front passivation and anti-reflection layer 12 disposed from bottom to top, wherein the front electrode 1 is located above a front surface of the front passivation and anti-reflection layer 12 and forms an ohmic contact with the front emitter 11, and the structure of the front electrode 1 is the same as that of embodiment 5. With reference to fig. 11, the method for manufacturing a solar cell of this embodiment specifically includes the following steps:

1. texturing: a single crystal P-type silicon wafer substrate 10 is adopted, and front and back texturing is carried out by alkali to form a textured structure.

2. Diffusion: and (3) reacting the silicon wafer after texturing with phosphorus oxychloride at high temperature to diffuse the front side to form a PN emitter junction (namely a front emitter 11). The sheet resistance of the front surface sheet after diffusion is between 160 omega/□.

3. Laser SE: and performing laser doping on the front surface of the diffused silicon wafer and the metalized area corresponding to the positive electrode grid line by using the diffused phosphorosilicate glass as a phosphorus source to form a heavily doped area 11-2, so that a structure (the heavily doped area 11-2 and the shallow doped area 11-1) for selecting an emitter is realized on the front surface of the silicon wafer. The square resistance of the heavily doped region is between 60 omega/□. As shown in fig. 12, the laser SE is doped only at the secondary gate of the positive electrode pattern, and compared with the conventional laser pattern, the laser doping of the main gate region is cancelled, that is, only the secondary gate laser doped region 16 exists, so that the area of the shallow diffusion region is increased, the surface recombination of the region caused by heavy doping and a laser process is reduced, the short-wave effect is improved, and the conversion efficiency of the cell is further improved. As shown in fig. 13, in order to ensure the overprinting precision of the positive electrode and the laser heavily doped region and the stability of yield rate during mass production, the laser spot of the laser SE is in a square or rectangular form, the width of the laser spot is 90-110 μm, and the distance between the laser spots 16-1 is 0-10 μm.

4. Thermal oxidation: and introducing oxygen into the silicon wafer after the laser SE for oxidation.

5. Removing PSG: and (4) removing the PSG on the back surface and the periphery of the silicon wafer after thermal oxidation by using HF.

6. Alkali polishing: and polishing the back and the edge of the silicon wafer after the PSG is removed, and removing the PSG on the front side.

7. Oxidizing and annealing: and (3) carrying out oxidation and annealing treatment on the silicon wafer subjected to the alkali polishing to form a front surface oxidation layer 13.

8. Depositing a passivation film on the back: and preparing a passivation film on the back of the annealed silicon wafer, and preparing a back passivation layer 14.

9. Front side deposition of an antireflection film: and preparing a passivation and antireflection layer 12 on the front surface of the silicon wafer.

10. Back laser: and carrying out laser drilling on the silicon wafer with the passivation film prepared on the back surface.

11. Back electrode printing: and carrying out screen printing on the silicon wafer after laser hole opening on the front side and the back side to prepare a back electrode.

12. Back side sub-grid printing: the back side sub-gate electrode 15 is screen printed on the printed back electrode silicon wafer.

13. Printing a positive electrode main gate region: the positive electrode main grid is prepared by adopting the front silver paste (solid content is 80-95%, tin-coating area is more than 80%, and pulling force average value is more than 1.0N) with high solid content, high weldability and no burn-through of silicon nitride, wherein the polymerization M3M-FB07-6 is adopted in the embodiment, and the main grid pattern adopts a main grid welding spot and a thin main grid (figure 9) mode on a silicon wafer printed with a back aluminum grid line. The main grids are more than or equal to 9 multi-main grids, the width of each thin main grid is 0.05mm, the thin main grids can be designed in a bamboo joint gradual change mode, and the gradual change specification is 0.03-0.1 mm.

14. Printing a positive electrode secondary grid region: adopting a non-mesh-junction screen plate, matching the non-mesh-junction positive silver slurry (the aspect ratio is more than 35%, in this embodiment, polymeric CSP-M3D-S6009V229) with excellent aspect ratio and burning through silicon nitride, and screen-printing on the silicon wafer printed with the positive electrode main gate to prepare a positive electrode auxiliary gate: with reference to fig. 6, the steel wires parallel to the secondary grid in the secondary grid line printing region 7 (i.e., the transverse steel wires 8 cut off by the laser in the secondary grid line printing region) are removed by cutting wires by laser, and the original mesh knots (i.e., the longitudinal and transverse steel wire knots 6) formed by the longitudinal steel wires 5 of the steel wire mesh and the transverse steel wires 4 of the steel wire mesh in the secondary grid region are eliminated. The pattern of the step adopts a mode of an auxiliary grid corresponding to the pattern of the main grid and a fish-fork thin main grid (figure 10); the secondary grids are arranged in parallel and uniformly with the grid line spacing of 1.22mm, the design line width of the secondary grids is 22 mu m, and the fish fork thin main grids (figure 7) are designed by S-shaped curves.

15. And (3) sintering: the silicon chip with the front electrode printed is co-sintered, the sintering peak temperature can be selected between 720 and 800 ℃ according to the requirement, and the region is taken out at 750 ℃.

16. Electric injection and finished product production: and (4) performing electric injection treatment on the sintered battery piece, and then testing, sorting, packaging and warehousing.

Example 7

The structure of the PERC solar cell of this embodiment is the same as that of embodiment 6, and when the PERC solar cell is manufactured, the pitch between the adjacent sub-grids 2 can be reduced to 1.13mm, the line width of the sub-grid 2 can be reduced to 20 μm, and the sintering temperature is 750 ℃.

Example 8

The structure of the PERC solar cell of this embodiment is the same as that of embodiment 6, and when the PERC solar cell is manufactured, the pitch between the adjacent sub-grids 2 can be reduced to 1.32mm, the line width of the sub-grid 2 can be reduced to 24 μm, and the sintering temperature is 760 ℃.

Example 9

The structure of the PERC solar cell of this embodiment is the same as that of embodiment 6, and when the cell is manufactured, the pitch of the grid lines of the adjacent sub-grids 2 can be reduced to 1.00mm, the line width of the sub-grid 2 can be reduced to 10 μm, and the sintering temperature is 755 ℃.

In combination with the above embodiment, the utility model discloses a design of many compound thin main grid structures and the thin main grid structure of S type fish spear, the mesh knot screen printing technology of vice bars and the substep printing in main grid district and vice grid district to can realize the promotion of PERC battery piece photoelectric conversion efficiency more than 0.1%, positive silver consumption reduces 3-10mg, broken the restriction of vice grid thick liquids to the too high tensile force demand in main grid district, can select respectively the thick liquids in main grid district and vice grid district as required, the metallization performance in vice grid district has been improved, can narrow down vice grid design linewidth to 10-26 mu m, and effectively reduce vice grid line spacing to 1.00-1.32 mm.

Claims (10)

1. A front electrode of a solar cell, the main grid (3) of which comprises a thin main grid (3-2) and solder joints (3-1) spaced apart on the thin main grid (3-2), characterized in that: the thin main grid (3-2) between the adjacent welding points (3-1) comprises a straight line thin main grid (3-2-2) connecting the two welding points and side thin main grids (3-2-1) positioned at two sides of the straight line thin main grid (3-2-2).

2. The front electrode of a solar cell according to claim 1, characterized in that: the widths of the linear thin main grid (3-2-2) and the lateral thin main grid (3-2-1) are both 0.06 +/-0.04 mm.

3. The front electrode of a solar cell according to claim 1, characterized in that: the side thin main grids (3-2-1) are divergently arranged relative to the welding spots (3-1), and the distance W2 between the two side thin main grids (3-2-1) is larger than the width of the welding spots (3-1).

4. The front electrode of a solar cell according to claim 3, characterized in that: the side thin main grid (3-2-1) between the adjacent welding points (3-1) is composed of straight lines or curves.

5. The front electrode of a solar cell according to claim 4, characterized in that: the side thin main grids (3-2-1) between the adjacent welding points (3-1) are straight lines parallel to the straight thin main grids (3-2-2), and the two ends of the side thin main grids are connected with the welding points (3-1) through transition connecting lines.

6. The front side electrode of a solar cell according to any one of claims 1 to 5, characterized in that: two ends of the straight line thin main grid (3-2-2) are respectively connected with the central areas of the two welding points (3-1), and the thin main grids (3-2-1) at the two side parts are symmetrically distributed around the straight line thin main grid (3-2-2).

7. The front side electrode of a solar cell according to any one of claims 1 to 5, characterized in that: the auxiliary grid (2) is formed by screen printing without net knots.

8. The front electrode of a solar cell according to claim 7, characterized in that: the two ends of the thin main grid (3-2) are provided with edge harpoon thin main grids (3-3), and the edge harpoon thin main grids (3-3) adopt an S-shaped curve design.

9. The front electrode of a solar cell according to claim 8, characterized in that: the grid line spacing of the adjacent auxiliary grids (2) is 1.00-1.32mm, and the line width of the auxiliary grids (2) is 10-26 mu m.

10. A high-efficiency high-reliability PERC solar battery is characterized in that: comprising a front electrode (1) according to any one of claims 1 to 9.

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