CN210897298U

CN210897298U - Solar cell and printing screen for solar cell

Info

Publication number: CN210897298U
Application number: CN201922344692.2U
Authority: CN
Inventors: 宋冲; 唐步玉; 潘岳林; 姜大俊; 潘励刚
Original assignee: Yancheng Artes Sunshine Energy Technology Co ltd; CSI Solar Power Group Co Ltd
Current assignee: Yancheng Artes Sunshine Energy Technology Co ltd; Canadian Solar Inc
Priority date: 2019-12-24
Filing date: 2019-12-24
Publication date: 2020-06-30
Anticipated expiration: 2029-12-24

Abstract

The utility model provides a solar wafer and be used for solar wafer's printing half tone. The solar cell comprises a silicon wafer and electrodes arranged on the surface of the silicon wafer, the electrodes comprise a plurality of main grids which are parallel and arranged at intervals, hollow areas are arranged on the main grids, the electrodes further comprise first thin grids and second thin grids which are formed at two sides of the hollow areas at intervals, the first thin grids and the second thin grids are located on the same straight line, the hollow areas comprise corner hollow areas of adjacent silicon wafer corners, the first thin grids and/or the second thin grids on two sides of the corner hollow areas are/is provided with extending parts which extend to the inner parts of the corner hollow areas in the extending direction of the first thin grids and/or the second thin grids, and the total length of the extending parts is smaller than the width of the corner hollow areas. The printing screen for the solar cell realizes the solar cell. The extension part can be accurately aligned to the position of the laser opening line corresponding to the extension part, so that whether the fine grid and the laser opening line are overlapped or not can be directly observed conveniently, problems can be found timely, and the product yield is improved.

Description

Solar cell and printing screen for solar cell

Technical Field

The utility model relates to a photovoltaic field especially relates to a solar wafer and be used for solar wafer's printing half tone that the convenience was examined solar wafer's electrode printing effect.

Background

The solar cell conversion efficiency is a direction of technical research in the field of photovoltaics, which is always dedicated to improvement, wherein the double-sided cell is favored because it can simultaneously achieve back power generation. In the production of the existing double-sided battery, the setting process flow of the back electrode is as follows: the method comprises the steps of firstly carrying out laser grooving on the back surface of a battery piece according to an electrode pattern design, then carrying out electrode printing on a laser opening line of the laser grooving in a screen printing mode, and finally sintering to form the battery. However, when screen printing is performed, particularly at the corner positions, the alignment of the back laser opening lines and the printed fine grid lines is not accurate, so that the back printing EL picture is often shifted abnormally. Especially, the line width and the interval of the thin grid lines are small, and the printing quality is difficult to judge by direct observation due to the fact that the back electrode is disconnected with the thin grid lines, so that the response to abnormity and the adjustment speed for solving abnormity are slow.

Therefore, it is necessary to solve the above problems to find the problems in time and improve the product yield.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a conveniently carry out visual detection to printing quality, and then improve the solar wafer of product yield and be used for solar wafer's printing half tone.

In order to realize the above application purpose, the utility model adopts the following technical scheme: the utility model provides a solar cell, includes the silicon chip, sets up the electrode on silicon chip surface, the electrode includes a plurality of parallels and the interval main bars that set up, be provided with the fretwork district on the main bars, the electrode still includes the interval and forms first thin bars and the second thin bars of fretwork district both sides, first thin bars and second thin bars are located same straight line, wherein: the hollow area comprises corner hollow areas at the corners of adjacent silicon wafers, the first thin grid and/or the second thin grid on two sides of each corner hollow area are/is provided with extending parts which extend to the insides of the corner hollow areas in the extending direction of the first thin grid and/or the second thin grid, and the total length of the extending parts is smaller than the width of the corner hollow areas.

Furthermore, the first fine grid and the second fine grid are respectively arranged on two sides of the corner hollow area in parallel, and the extension part is formed by extending the first fine grid and/or the second fine grid close to the edge of the silicon wafer.

As an embodiment of the present invention, the main grid includes the edge main grid that adjacent silicon chip edge set up, perpendicular in the direction of main grid extending direction, the hollow area still including set up in on the edge main grid and adjacent the middle part hollow area of silicon chip central line, middle part hollow area both sides first thin grid and/or the thin grid of second have the extension that extends to the inside of middle part hollow area on its extending direction.

As an embodiment of the utility model provides a further improvement, middle part fretwork district both sides set up many respectively first thin bars and the thin bars of second, the extension is by adjacent the thin bars of first thin bars and the thin bars of second of silicon chip central line extend and form.

Preferably, the width of the hollow-out area is 1.8mm, and the extension lengths of the two extension parts in the middle hollow-out area are respectively 0.5 mm.

As an embodiment of the present invention, the hollow area center position sets up the welding electrode, welding electrode and hollow area both sides contact, welding electrode follows main bars direction length is less than hollow area length, welding electrode with the extension interval set up in follow in the hollow area main bars direction welding electrode both sides.

As a further improvement of an embodiment of the present invention, the thin grid structure further comprises a plurality of parallel and spaced thin grids, the first thin grid and the second thin grid belong to a part of the thin grid, a plurality of the thin grids are all connected perpendicularly to the main grid.

As a further improvement of an embodiment of the present invention, in the arrangement direction of the thin grid, the wire diameter of the thin grid gradually increases from the center line of the silicon wafer to the two side directions.

Preferably, in the arrangement direction of the fine grids, 156 fine grids are arranged, the wire diameter of the two middle fine grids is 130-150 μm, and the wire diameter difference of the two adjacent fine grids from the middle fine grid to the outside is 0.6-1 μm.

The utility model also provides a printing half tone for solar wafer has and hides district and mesh district, the mesh district with above-mentioned any one of all technical scheme the pattern phase-match of electrode.

The utility model has the advantages that: through the inside thin bars extension that sets up in bight fretwork district, the extension can be accurate to the corresponding laser opening line position with it, and whether the direct observation thin bars of being convenient for and laser opening line coincide, in time discover the problem, promote the product yield. The printing screen for the solar cell slice realizes the solar cell slice, the process flow is consistent with the conventional printing flow, the operation is simple, and the consumption of the total slurry is not increased.

Drawings

FIG. 1 is a schematic diagram of a printed electrode pattern according to a preferred embodiment of the present invention;

FIG. 2 is an enlarged view of a portion of the area A in FIG. 1;

fig. 3 is a partially enlarged view of the region B in fig. 1.

The manufacturing method comprises the following steps of 1-silicon chip, 2-electrode, 21-main grid, 22-fine grid, 23-welding electrode, 210-edge main grid, 2100-hollowed-out area, 2101-corner hollowed-out area, 2102-middle hollowed-out area, 221-first fine grid, 222-second fine grid, 223-extending part, 224-outer frame grid line and 3-laser opening line.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

The present invention will be described in detail below with reference to specific embodiments shown in the drawings. However, these embodiments are not intended to limit the present invention, and structural, methodical, or functional changes that may be made by one of ordinary skill in the art based on these embodiments are all included in the scope of the present invention.

In the various drawings of the present invention, certain dimensions of structures or portions may be exaggerated relative to other structures or portions for ease of illustration, and thus, are used only to illustrate the basic structure of the subject matter of the present invention.

As shown in fig. 1, the solar cell of the present invention includes a silicon wafer 1 and an electrode 2 disposed on the surface of the silicon wafer 1.

The silicon wafer 1 in this embodiment is a silicon wafer substrate for a double-sided battery, and is formed by conventional texturing, diffusion, etching, double-sided coating, laser grooving and other processes.

The electrode 2 is positioned on the back surface of the silicon wafer 1, is formed by sintering metal slurry printed by a screen printing process, and is mainly used for collecting and conducting current generated by the solar cell.

Correspondingly, the electrode 2 includes a plurality of main grids 21 arranged in parallel and at intervals, the main grids 21 are formed after printing and sintering aluminum paste, and the intervals between the main grids 21 are equal, wherein the main grids 21 include two edge main grids 210 arranged adjacent to the edges of the silicon wafer 1, in other words, the edge main grids 210 are respectively located at two opposite edges of the adjacent silicon wafer 1, and the distance from the edge main grids 210 to the edges of the silicon wafer 1 is half of the interval between the main grids 21. Preferably, the number of the main gates 21 is 9, and the line width of the main gate is 1.4mm, but is not limited thereto.

Further, the same number of hollow areas 2100 are arranged on each main grid 21 at intervals, each hollow area 2100 is a rectangle extending along the length direction of the main grid 21, and a connecting frame connected with the main grid 21 is formed around each hollow area 2100. In the actual production and printing process, the main grid 21 and the connection frame around the hollow area 2100 are printed and formed at the same time.

Wherein, all the hollow-out areas 2100 have the same shape, length, width and size. Preferably, the width of the hollow area 2100 is 1.8mm, and the width of the frame is 0.6mm, but not limited thereto.

Further, as shown in fig. 1, the hollow areas 2100 include corner hollow areas 2101 adjacent to corners of the silicon wafer 1, that is, the corner hollow areas 2101 are the hollow areas 2100 located at two ends of the edge main grid 210. Therefore, the solar cell includes 4 angular hollow-out regions 2201.

As a preferred embodiment, the electrode 2 further includes a first fine grid 221 and a second fine grid 222 formed at both sides of the corner hollow region 2101 at an interval. As shown in fig. 2, the first fine gate 221 and the second fine gate 222 are located on the same straight line. The first fine grid 221 and/or the second fine grid 222 on both sides of the corner hollow area 2101 have an extension 223 extending to the inside of the corner hollow area 2202 in the extension direction thereof, and the total length of the extension 223 is smaller than the width of the corner hollow area 2101.

Preferably, the first fine grid 221 and the second fine grid 222 are respectively and vertically connected to the frame of the corner hollow area 2101, and a plurality of the first fine grid 221 and the second fine grid 222 are respectively arranged in parallel on two sides of the corner hollow area 2101, and the distance between the first fine grid 221 and the second fine grid 222 is equal.

Further, the extension 223 may be only formed by extending the first fine gate 221 and/or the second fine gate 222 near the edge of the silicon chip 1 in the extending direction. Here, the edge of the silicon wafer 1 is an edge parallel to the linear direction of the first fine grid 221 or the second fine grid 222.

Further, the extension portion 223 may be formed by extending the first fine bar 221 alone, or extending the second fine bar 222 alone, or extending the first fine bar 221 and the second fine bar 222 together into the corner hollow region 2101.

Accordingly, the length of each of the extensions 223 is not limited, but the total length of the extensions 223 should be smaller than the inner width of the corner hollow area 2101. This design facilitates to see if the extension 223 is aligned coincident with the laser opening line 3 below the extension 223. The laser opening line 3 is arranged on the surface of the solar cell piece and comprises a plurality of parallel thin grids 22 at the same positions at intervals, the laser opening line 3 is positioned below the thin grids 22 and covered by the thin grids 22, and aluminum slurry in the thin grids is diffused into the silicon chip 1 through the laser opening line 3 to form a back electric field when sintering is facilitated.

As a preferred embodiment, as shown in fig. 3, in a direction perpendicular to the extending direction of the main grid, the hollow area further includes a middle hollow area disposed on the edge main grid and adjacent to the central line of the silicon wafer. In other words, the middle hollow area 2102 is located in the middle of the edge main grid 210, when the main grid 21 is provided with an even number of the hollow areas 2100, the middle hollow area 2102 is two middle hollow areas 2100, and when the main grid 21 is provided with an odd number of the hollow areas 2100, the middle hollow area 2102 is 1 middle hollow area 2100.

Correspondingly, the first fine grid 221 and the second fine grid 222 on two sides of the middle hollow-out area 2102 also have extending portions 223 extending to the inside of the middle hollow-out area 2102 in the extending direction thereof, and the two extending portions 223 inside the middle hollow-out area 2102 have the same length, which is 0.5mm respectively. In this way it is directly observable whether the laser opening line 3 and the two extensions 223 are in a straight line.

Further, a welding electrode 23 is disposed at a central position in each of the hollow areas 2100, the welding electrode 23 is a part of the electrode 2, and the welding electrode 23 is formed by printing and sintering a paste with excellent conductivity, and mainly functions to conduct current and serve as a welding position for series connection of batteries in subsequent assembly manufacturing.

Preferably, the welding electrode 23 is rectangular, the welding electrode 23 contacts with two sides of the hollow area 2100, and the length of the welding electrode 23 along the direction of the main grid 21 is smaller than the length of the hollow area 2100. In other words, the short side of the welding electrode 23 is equal to the inner width of the hollow area 2100, that is, the long side of the welding electrode 23 directly contacts the long side of the hollow area 2100, and the welding electrode 23 and the extension portion 223 are disposed at intervals on two sides of the welding electrode 23 along the direction of the main grid 21 in the hollow area 2100.

As a preferred embodiment, as shown in fig. 1, the solar cell includes a plurality of parallel thin grids 22 arranged at intervals and an outer frame grid line 224 arranged along the edge of the silicon wafer, the first thin grid 221 and the second thin grid 222 belong to a part of the thin grids 22, two end edges of each thin grid 22 perpendicularly intersect with the outer frame grid line 224 to form a loop, the outer frame grid line 224 is parallel to the main grid 21, the diameter of the outer frame grid line 224 is not smaller than that of the thin grid 22, and the specific diameter is set to be a suitable size according to the requirement.

As shown in fig. 1, each of the fine grids 22 is vertically connected to the main grid arrangement, and the number of the fine grids is 156, but the invention is not limited thereto. The line spacing of each fine grid 22 can be set to be the same, and can also be specially set according to requirements.

Preferably, in the arrangement direction of the fine grids 22, the diameter of the fine grids 22 gradually increases from the center line of the silicon wafer 1 to both sides, in other words, the diameter of two fine grids 22 adjacent to the silicon wafer 1 at the position perpendicular to the center line of the main grid 21 is the smallest, and is 130 μm to 150 μm. The minimum wire diameter of the thin grid 22 of the utility model is smaller than the wire diameter of the common thin grid. If the number of the fine grids 22 is odd, the number of the fine grids 22 with the smallest line diameter is one.

Further, the difference between the line diameters of two adjacent fine grids 22 is 0.6 μm to 1 μm from the middle of the fine grid 22 to the outside, and it is not limited whether the line pitches between the two fine grids 22 are the same or not. The utility model discloses technical scheme adopts and increases the edge the mode of thin bars 22 line footpath size can be guaranteed as far as possible thin bars 22 cover laser opening line 3 reduces the printing skew influence.

It should be noted that the design of the electrode 2 of the solar cell shown above is used in terms of whether the fine grid 22 and the laser opening 3 are aligned at the corners and edges, but the design idea of the electrode 2 can also be used in terms of alignment requirements of other electrodes, and is not limited to the front surface or the back surface of the solar cell, and is not limited to the structure type of the solar cell.

The utility model provides a be used for screen printing to make solar wafer's printing otter board, printing otter board is including covering district and mesh district, it corresponds to cover the district 1 surface on silicon chip does not have the region of electrode 2, mesh district and above any kind of embodiment the pattern phase-match of electrode 2. That is, the paste is transferred to the back surface of the silicon wafer 1 of the solar cell through the mesh region of the printing screen, in which the shape of the mesh region matches the shape of the pre-formed electrode 2.

To sum up, the utility model provides a solar cell, including silicon chip 1, set up electrode 2 on silicon chip 1 surface, wherein electrode 2 includes the main bars 21 that a plurality of parallels and interval set up, be provided with fretwork area 2100 on the main bars 21, electrode 2 still includes first thin bars 221 and the second thin bars 222 that the interval formed at fretwork area 2100 both sides, wherein first thin bars 221 and second thin bars 222 are located same straight line, fretwork area 2100 includes the bight fretwork area 2101 of adjacent silicon chip 1 bight, first thin bars 2101 and/or the second thin bars 2101 of bight fretwork area 2101 both sides have in its extending direction extends to the inside extension 223 of bight fretwork area 2101, wherein the total length of extension 223 is less than the width of bight fretwork area 2101. Because the thin grid extension part 223 is arranged in the corner hollow-out area 2101, the extension part 223 can be accurately aligned to the position of the laser opening line 3 corresponding to the thin grid extension part, so that whether the thin grid 22 and the laser opening line 3 coincide or not can be directly observed conveniently, problems can be found in time, and the product yield is improved. By combining the design mode that the line diameter of the thin grid 22 is gradually increased from the center line of the silicon wafer 2 to the two sides in the arrangement direction of the thin grid 22, the thin grid 22 can be ensured to cover the laser opening line 3 as much as possible, the printing offset influence is reduced, the product yield is improved, the total electrode shading area is not increased, and the solar cell efficiency is not influenced. The printing screen for the solar cell slice is consistent with the conventional printing process, is simple to operate and does not increase the consumption of the total slurry.

It should be understood that although the present description refers to embodiments, not every embodiment contains only a single technical solution, and such description is for clarity only, and those skilled in the art should make the description as a whole, and the technical solutions in the embodiments can also be combined appropriately to form other embodiments understood by those skilled in the art.

The above list of details is only for the practical implementation of the present invention, and they are not intended to limit the scope of the present invention, and all equivalent implementations or modifications that do not depart from the technical spirit of the present invention should be included in the scope of the present invention.

Claims

1. The utility model provides a solar cell, includes the silicon chip, sets up the electrode on silicon chip surface, the electrode includes the main bars that a plurality of parallels and interval set up, be provided with the fretwork district on the main bar, the electrode still includes that the interval forms the first thin bars and the second thin bars of fretwork district both sides, first thin bars and second thin bars are located same straight line, its characterized in that: the hollow area comprises corner hollow areas at the corners of adjacent silicon wafers, the first thin grid and/or the second thin grid on two sides of each corner hollow area are/is provided with extending parts which extend to the insides of the corner hollow areas in the extending direction of the first thin grid and/or the second thin grid, and the total length of the extending parts is smaller than the width of the corner hollow areas.

2. The solar cell sheet according to claim 1, wherein: the first thin grid and the second thin grid are respectively arranged on two sides of the corner hollow area in parallel, and the extension part is formed by extending the first thin grid and/or the second thin grid close to the edge of the silicon wafer.

3. The solar cell sheet according to claim 2, wherein: the main grid comprises an edge main grid arranged at the edge of an adjacent silicon chip, the hollowed-out area also comprises a middle hollowed-out area which is arranged on the edge main grid and is adjacent to the central line of the silicon chip in the direction vertical to the extending direction of the main grid, and the first thin grid and/or the second thin grid at two sides of the middle hollowed-out area are/is provided with extending parts which extend to the inside of the middle hollowed-out area in the extending direction of the first thin grid and/or the second thin grid.

4. The solar cell sheet according to claim 3, wherein: and a plurality of first fine grids and second fine grids are respectively arranged on two sides of the middle hollow area, and the extension part is formed by extending the first fine grids and the second fine grids adjacent to the central line of the silicon wafer.

5. The solar cell sheet according to claim 4, wherein: the width of the hollow-out area is 1.8mm, and the extension lengths of the two extension parts in the middle hollow-out area are respectively 0.5 mm.

6. The solar cell sheet according to any one of claims 2 to 5, wherein: the central position of the hollowed-out area is provided with a welding electrode, the welding electrode is in contact with the two sides of the hollowed-out area, the length of the welding electrode along the main grid direction is smaller than that of the hollowed-out area, and the welding electrode and the extension part are arranged in the hollowed-out area at intervals and along the two sides of the welding electrode along the main grid direction.

7. The solar cell sheet according to claim 1, wherein: the first fine grid and the second fine grid belong to one part of the fine grid, and the fine grids are vertically connected with the main grid.

8. The solar cell sheet according to claim 7, wherein: and in the arrangement direction of the fine grids, the wire diameter of the fine grids is gradually increased from the central line of the silicon wafer to the two sides.

9. The solar cell sheet according to claim 8, wherein: in the arrangement direction of the fine grids, 156 fine grids are arranged, the wire diameter of two middle fine grids is 130-150 mu m, and the wire diameter difference of two adjacent fine grids from the middle fine grid to the outside is 0.6-1 mu m.

10. A printing half tone for solar wafer, have and hide district and mesh area, characterized by: the mesh region matches the pattern of the electrode of any one of claims 1 to 9.