CN215266318U - Structure of tin-copper metal grid line of solar cell - Google Patents
Structure of tin-copper metal grid line of solar cell Download PDFInfo
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- CN215266318U CN215266318U CN202121827390.1U CN202121827390U CN215266318U CN 215266318 U CN215266318 U CN 215266318U CN 202121827390 U CN202121827390 U CN 202121827390U CN 215266318 U CN215266318 U CN 215266318U
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Abstract
The utility model relates to a structure of solar cell tin copper metal grid line, including setting up the silicon nitride layer on solar cell silicon substrate, according to a plurality of type silver thick liquid column points of burning through of line or row evenly distributed on silicon nitride layer, burn through type silver thick liquid column point and pierce through silicon nitride layer, set up the grid line on every line or every row type silver thick liquid column point of burning through, burn through type silver thick liquid column point's one end and solar cell silicon substrate coupling, the other end and grid line coupling, this grid line is tin copper metal grid line. In the solar cell grid line structure of this application, adopt the tin cream of high conductivity to replace silver thick liquid to prepare into tin copper metal grid line, tin copper metal grid line replaces silver thick liquid grid line, has not only reduced solar cell's series resistance, has reduced solar cell's metallization cost moreover.
Description
Technical Field
The application relates to the technical field of solar cells, in particular to a tin-copper metal grid line structure of a solar cell.
Background
In recent years, high-efficiency photoelectric conversion solar cells are continuously concerned by the solar cell industry, and the photoelectric conversion efficiency of the solar cells is continuously improved. Particularly, for carrier selective cells such as TOPCon cells and HJT cells, the capacity of new production lines of domestic TOPCon and HJT solar cells is increased explosively, and the capacity of IBC cells and TBC cells without grid lines on the front side is also increased continuously. For the TOPCon battery, the grid line on the front surface adopts continuous burn-through type silver-aluminum paste, and the grid line formed by the process is not only contacted with a silicon substrate, but also can cause serious carrier recombination, so that the solar battery cannot obtain higher open-circuit voltage. For the problem of carrier recombination caused by contact between a semiconductor and a metal, a double-layer printing process is adopted, specifically, a lower layer adopts point-contact type burn-through slurry, contact resistance is guaranteed, meanwhile, the metal-semiconductor recombination is effectively reduced, and an upper layer adopts linear continuous non-burn-through slurry, so that the obtained grid line has excellent line resistance, the damage of the metal to a polycrystalline silicon layer is further reduced, and the advantage of a polycrystalline silicon passivation structure is exerted to the maximum extent. Meanwhile, the back electrodes of the traditional IBC battery and the novel TBC battery also adopt a double-layer printing process to prepare the grid line electrode.
However, the bi-layer printing process increases the series resistance of TOPCon, IBC cells, and also increases the metallization cost of solar cells.
SUMMERY OF THE UTILITY MODEL
The application provides a structure of a tin-copper metal grid line of a solar cell, which aims to solve the problems that the grid line series resistance of the traditional solar cell prepared by adopting a double-layer printing process is large and the metallization cost of the solar cell is high.
The technical scheme adopted by the application for solving the technical problems is as follows:
a structure of a tin-copper metal grid line of a solar cell comprises: the silicon nitride layer of setting on solar cell silicon substrate is in according to line or row evenly distributed a plurality of type silver thick liquid column points of burn through on the silicon nitride layer, burn through type silver thick liquid column point and pierce through silicon nitride layer sets up at every line or every row burn through the grid line on the type silver thick liquid column point, burn through the one end of type silver thick liquid column point with solar cell silicon substrate coupling, the other end of type silver thick liquid column point with the grid line coupling, the grid line is tin copper metal grid line.
Furthermore, the diameter of the column points of the burn-through silver paste is 20-100 μm.
Further, the distance between adjacent burning-through silver paste column points is 100-500 μm.
Further, the width of the grid line is 30-100 μm.
Further, the height-to-width ratio of the grid line is 0.2-1.5.
Further, the materials of the burn-through type silver paste column points comprise silver paste and silver-aluminum paste.
The technical scheme provided by the application comprises the following beneficial technical effects:
the application provides a solar cell tin copper metal grid line structure, including setting up the silicon nitride layer on solar cell silicon substrate, according to a plurality of type silver thick liquid column points of burning through of line or row evenly distributed on silicon nitride layer, burn through type silver thick liquid column point and pierce through silicon nitride layer, set up the grid line on every line or every row type silver thick liquid column point of burning through, burn through type silver thick liquid column point's one end and solar cell silicon substrate coupling, the other end and grid line coupling, this grid line is tin copper metal grid line. In the solar cell tin-copper metal grid line structure of this application, adopt the tin cream of high conductivity to replace silver thick liquid to prepare into tin-copper metal grid line, tin-copper metal grid line has replaced silver thick liquid grid line, has not only reduced solar cell's series resistance, has reduced solar cell's metallization cost moreover.
Drawings
Fig. 1 is a schematic view of a tin-copper metal grid line structure of a solar cell provided in an embodiment of the present application;
fig. 2 is a schematic top view of a tin-copper metal grid line structure of a solar cell according to an embodiment of the present application.
Description of reference numerals: 1-grid line, 2-silicon nitride layer, 3-solar cell silicon substrate and 4-burn-through type silver paste column points.
Detailed Description
To facilitate the description and understanding of the technical solutions of the present application, some concepts related to the present application will be described first below.
The TOPCon (tunnel Oxide passivation contacts) battery is a tunneling Oxide passivation contact battery.
The IBC (indirect back contact) cell is a back-junction back-contact solar cell structure in which positive and negative metal electrodes are arranged on the backlight surface of the cell in an interdigital mode.
The present application is described in further detail below with reference to the attached figures.
As shown in fig. 1, for the schematic structural diagram of the solar cell tin-copper metal gate line provided in the embodiment of the present application, the solar cell tin-copper metal gate line includes a silicon nitride layer 2 disposed on a solar cell silicon substrate 3, a plurality of fire-through type silver paste column points 4 disposed on the silicon nitride layer 2, a gate line 1 disposed on the fire-through type silver paste column points 4, one end of the fire-through type silver paste column points 4 is coupled with the solar cell silicon substrate 3, and the other end is coupled with the gate line 1.
As shown in fig. 2, in the schematic plan view of the tin-copper metal grid line structure of the solar cell provided in the embodiment of the present application, as shown in the drawing, the fire-through silver paste column points 4 are uniformly distributed on the silicon nitride layer 2 according to rows or columns, the fire-through silver paste column points 4 in each row have the same number, and the row number or column number of the fire-through silver paste column points 4 arranged on the silicon nitride layer 2 is set according to the number of the grid lines 1, that is, the row number or column number of the fire-through silver paste column points 4 required to be arranged on one surface of each solar cell is the same as the number of the grid lines 1 required to be arranged on the surface. Grid line 1 is fixed the setting on the surface of silicon nitride layer 2 through type silver thick liquid post point 4 that burns through, and silver thick liquid or silver-aluminium thick liquids can be selected to the material of type silver thick liquid post point 4 that burns through, and the tin cream that contains tin and copper is selected to the material of grid line 1, and grid line 1 is tin copper metal grid line promptly.
In the specific implementation process, taking a TOPCon battery as an example, the solder paste comprises 10% of solder paste and 90% of metal powder by mass, wherein the metal powder comprises copper powder andthe mass ratio of the tin powder to the copper powder to the tin powder is 4: 1, the copper powder is spherical and has a layer of tin, nickel or silver simple substance plating layer on the surface, the thickness of the plating layer is less than 2 μm, and the particle size of the copper powder is less than 25 μm. The tin powder is high-temperature tin-silver-copper (Sn)0.3Ag0.7Cu) alloy powder, wherein the tin powder is spherical tin powder, and the particle size is less than 25 mu m. The flux paste, the copper powder and the high-temperature tin-silver-copper (Sn)0.3Ag0.7Cu) alloy powder, and stirring uniformly to prepare the low-fluidity solder paste. Selecting a TOPCon cell with the size of 158.75 x 158.75mm and the front surface of which is finished with electrode grid lines, printing point contact burn-through type silver-aluminum paste column points on the front surface of the TOPCon cell, wherein the average diameter of the burn-through type silver-aluminum paste column points is 35 mu m, the center distance between every two adjacent silver-aluminum paste column points is 100 mu m, sintering at the temperature of 750 and 800 ℃, burning through the silicon nitride layer by the silver-aluminum paste, preparing the burn-through type silver paste column points which form ohmic contact with a solar cell silicon substrate, preparing prepared tin paste on the burn-through type silver paste column points on the front surface of the TOPCon cell by a screen printing process to form a grid line, and then carrying out heat treatment for 5-6 minutes in reflow soldering to form the tin-copper metal grid line.
TABLE 1TOPCon cell Sn-Cu metal grid line measurement results
| Serial number | Grid line width (mum) | Aspect ratio | Line resistance (omega) | Line resistivity (omega/cm) |
| 1 | 38.5 | 1.05 | 6.396 | 0.405 |
| 2 | 37.9 | 0.95 | 6.599 | 0.418 |
| 3 | 35.2 | 0.89 | 7.651 | 0.484 |
| 4 | 40.3 | 1.12 | 5.837 | 0.369 |
| 5 | 36.1 | 0.97 | 7.274 | 0.461 |
The tin-copper metal grid lines on the TOPCon cell were measured and the results are shown in table 1. As can be seen from the results in table 1, the average value of the widths of the tin-copper metal grid lines is 37.6 μm, the average value of the aspect ratios is 0.99, the average value of the line resistances is 6.751 Ω, and the average value of the line resistances is 0.427 Ω/cm.
Taking the IBC cell as an example, selecting an IBC cell with a size of 166 × 166mm, preparing a dot-shaped fire-through silver paste in an N-type region on the back of the IBC cell by a screen printing process, and preparing a dot-shaped fire-through silver-aluminum paste in a P-type region by a screen printing process, wherein the diameter of the dot-shaped silver-aluminum paste is 30-100 μm, and the distance between the point of the silver-aluminum paste and the point is 100-. Sintering the IBC battery with the patterned point burn-through type silver paste and the patterned point burn-through type silver aluminum paste, wherein the sintering temperature is 600-1000 ℃, so that glass materials in the point silver paste and the patterned point burn-through type silver aluminum paste etch a silicon nitride layer of the IBC battery, a penetrated burn-through hole is formed in the silicon nitride layer, metal particles in the silver paste and the patterned point burn-through type silver paste are melted in the burn-through hole, the melted metal particles are solidified in the burn-through hole along with the reduction of the temperature, a burn-through type silver paste column point is formed, and the burn-through type silver paste column point is directly contacted with a silicon substrate to form ohmic contact. And on the burning-through silver paste column points which form ohmic contact after sintering, preparing a solder paste grid line by screen printing or transfer printing by using solder paste with the same components as the solder paste grid line of the TOPCon battery, carrying out heat treatment on the solder paste grid line to volatilize organic components in the solder paste grid line, and melting the solder powder to connect the copper powder to form a compact high-conductivity solder-copper metal grid line.
The results of the measurements on the tin-copper metal grid lines of the IBC cell are shown in table 2. The results in table 2 show that the average value of the width of the tin-copper metal grid line is 80.5 μm, the average value of the aspect ratio is 0.84, the average value of the line resistance is 10.426 Ω, and the average value of the line resistance is 0.571 Ω/cm, and the same measurement result shows that compared with the non-fire-through silver paste, the line resistance of the tin-copper metal grid line is reduced, so that the photoelectric conversion efficiency of the IBC battery can be improved.
TABLE 2 Whole line measurement and test results for IBC cells
| Serial number | Grid line width (mum) | Aspect ratio | Line resistance (omega) | Line resistivity (omega/cm) |
| 1 | 80.5 | 0.25 | 10.375 | 0.625 |
| 2 | 80.8 | 0.95 | 10.425 | 0.628 |
| 3 | 80.4 | 0.89 | 10.473 | 0.631 |
| 4 | 80.6 | 1.12 | 10.094 | 0.361 |
| 5 | 80.4 | 0.97 | 10.762 | 0.608 |
When the tin-copper metal grid line structure of the solar cell provided by the embodiment of the application is prepared on different types of solar cells, it can be known from the two specific implementation processes that the width of the tin-copper metal grid line prepared by using the tin paste in the embodiment of the application is 30-100 μm, the aspect ratio of the tin-copper metal grid line is 0.2-1.5, and the line resistivity of the tin-copper metal grid line is 0.4-0.6 Ω/cm. According to the embodiment of the application, the silver paste of the original process is replaced by the high-conductivity tin paste, so that the metallization cost of the solar cell is effectively reduced; the tin-copper metal grid line prepared by using the tin paste with high copper powder content has lower line resistivity than the silver paste grid line prepared by using silver paste, and the high-conductivity tin-copper metal grid line reduces the series resistance of the solar cell and improves the photoelectric conversion efficiency of the solar cell; the tin-copper metal grid line can be overlapped with the multi-main grid and can also be overlapped with the non-main grid, and the tin-copper metal grid line and the non-main grid can both realize welding with higher reliability.
Claims (6)
1. The utility model provides a structure of solar cell tin copper metal grid line which characterized in that includes: set up silicon nitride layer (2) on solar cell silicon substrate (3), according to the line or be listed as evenly distributed and be in a plurality of type silver thick liquid column points (4) of burning through on silicon nitride layer (2), type silver thick liquid column points (4) of burning through pierce through silicon nitride layer (2), set up at every line or every row grid line (1) on type silver thick liquid column points (4) of burning through, the one end of type silver thick liquid column points (4) of burning through with solar cell silicon substrate (3) coupling, the other end of type silver thick liquid column points (4) of burning through with grid line (1) coupling, grid line (1) is tin copper metal grid line.
2. The structure of a tin-copper metal grid line of a solar cell according to claim 1, wherein the diameter of the fire-through silver paste column dots (4) is 20-100 μm.
3. The structure of a tin-copper metal grid line of a solar cell as claimed in claim 1, wherein the distance between adjacent fire-through silver paste pillar points (4) is 100-500 μm.
4. The structure of a tin-copper metal grid line of a solar cell according to claim 1, wherein the width of the grid line (1) is 30-100 μm.
5. The structure of a tin-copper metal grid line of a solar cell according to claim 1, wherein the height-to-width ratio of the grid line (1) is 0.2-1.5.
6. The structure of a tin-copper metal grid line of a solar cell according to claim 1, wherein the material of the fire-through type silver paste pillar dots (4) comprises silver paste and silver-aluminum paste.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024017801A1 (en) * | 2022-07-19 | 2024-01-25 | International Solar Energy Research Center Konstanz E.V. | Method for producing semiconductor-metal contacts of a solar cell, and solar cell |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024017801A1 (en) * | 2022-07-19 | 2024-01-25 | International Solar Energy Research Center Konstanz E.V. | Method for producing semiconductor-metal contacts of a solar cell, and solar cell |
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