SE-TOPCon battery

Abstract

The utility model relates to an SE-TOPCon battery, and belongs to the technical field of photovoltaic battery manufacturing. Comprising a P + + region; the P + + area comprises four rectangular marks, four positioning patterns and a plurality of SE laser lines. Four rectangular marks, four positioning patterns and a plurality of SE laser lines are arranged, the SE laser lines are carved on the front face of an N-type battery silicon wafer in parallel at equal intervals, the four rectangular marks and the four positioning patterns are carved at the four corners of the front face of the N-type battery silicon wafer respectively, and the four positioning patterns are located on the inner sides of the four rectangular marks respectively. When silk-screen printing is carried out, after a silk-screen printing plate grabs four positioning patterns to carry out preliminary positioning on an N-type battery silicon wafer, a worker carries out accurate positioning according to the coverage degree of the silk-screen printing plate patterns on four rectangular marks and a plurality of SE laser lines, so that the position deviation of a plurality of metal grid lines and a plurality of SE laser lines is reduced; and the photoelectric conversion efficiency of the SE-TOPCon battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic cell manufacturing, in particular to a SE-TOPCon cell. Background Art

[0002] As the economy continues to develop, energy consumption is increasing day by day, and environmental issues are becoming increasingly severe. As a green, pollution-free renewable energy, solar energy is one of the important sources of energy consumption for mankind in the future and has broad development prospects. However, high production costs and low efficiency have always been factors that plague the development of silicon-based batteries. Therefore, improving the conversion efficiency of photovoltaic cells and reducing production costs are huge challenges facing the industry.

[0003] In recent years, the SE-TOPCon cell formed by combining the selective emitter (SE) technology with the tunneling oxide passivation contact technology has become the mainstream product of crystalline silicon photovoltaic cells. The P++ area in the SE-TOPCon cell is formed by SE technology, using high-energy laser pulses to melt the surface of the silicon wafer to form SE laser lines, so that the phosphorus atoms in the phosphorus silicon glass are doped into the molten area to achieve heavy doping. On this basis, when the metal grid line formed by screen printing contacts the SE laser line, it can reduce the contact resistance between the front electrode and the cell silicon wafer, and reduce the recombination rate on the surface of the cell silicon wafer, thereby increasing the short-circuit current and open-circuit voltage of the SE-TOPCon cell, and then improving the conversion efficiency of the SE-TOPCon cell.

[0004] However, when screen printing is currently performed on SE-TOPCon cells, the front SE laser line and the screen-printed metal grid line are often offset due to inaccurate screen positioning, resulting in the SE laser line being exposed or overlapping, and the metal grid line and SE laser line having a low coverage, resulting in a dark EL image after sintering, and low short-circuit current, open-circuit voltage, fill factor and SE-TOPCon cell conversion efficiency. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a SE-TOPCon cell that improves the coverage of SE laser lines and metal grid lines. The technical solution of the utility model is as follows:

[0006] A SE-TOPCon battery, the SE-TOPCon battery comprises, from top to bottom, a front electrode, a front silicon nitride anti-reflection film layer, an aluminum oxide passivation layer, a P++ region, a P+ layer, an N-type battery silicon wafer, a tunneling oxide layer, an ultra-thin silicon oxide layer, an N-type polysilicon thin film layer, a back silicon nitride anti-reflection film layer and a back electrode; the P++ region comprises four rectangular marks, four positioning patterns and a plurality of SE laser lines, the plurality of SE laser lines are engraved in parallel and at equal intervals on the front of the N-type battery silicon wafer, the four rectangular marks are respectively engraved at the four corners of the front of the N-type battery silicon wafer, the four positioning patterns are respectively engraved at the four corners of the front of the N-type battery silicon wafer and are respectively located on the inner sides of the four rectangular marks; the two vertically distributed rectangular marks are distributed at both ends of the same SE laser line.

[0007] Optionally, the shapes of the four positioning patterns are all cross-shaped.

[0008] Optionally, the length of the plurality of SE laser lines is the same as the width of the SE-TOPCon cell; and the etching width of each SE laser line is 70-100 μm.

[0009] Optionally, the number of the SE laser lines engraved in the P++ zone is 154-200.

[0010] Optionally, the etching size of each rectangular mark is 3-20 mm in length and 75-150 μm in width.

[0011] All the optional technical solutions mentioned above can be combined arbitrarily, and the present utility model does not provide detailed descriptions of the structures after the combinations one by one.

[0012] By means of the above scheme, the beneficial effects of the utility model are as follows:

[0013] The P++ area of ​​the SE-TOPCon battery is set to include four rectangular marks, four positioning patterns and multiple SE laser lines. The multiple SE laser lines are engraved in parallel and at equal intervals on the front side of the N-type battery silicon wafer, the four rectangular marks are respectively engraved at the four corners of the front side of the N-type battery silicon wafer, the four positioning patterns are respectively engraved at the four corners of the front side of the N-type battery silicon wafer and are respectively located on the inner sides of the four rectangular marks, and the two vertically distributed rectangular marks are distributed at both ends of the same SE laser line. When screen printing is performed, the screen printing screen performs preliminary positioning on the N-type battery silicon wafer by grabbing the four positioning patterns of the P++ area, and the staff continues to accurately position the screen pattern through the coverage of the four rectangular marks and the multiple SE laser lines, thereby reducing the position deviation of the multiple metal grid lines and the multiple SE laser lines during screen printing of the SE-TOPCon battery, improving the short-circuit current, open-circuit voltage, filling factor and photoelectric conversion efficiency of the SE-TOPCon battery, and solving the problem of dark EL image after sintering of the SE-TOPCon battery.

[0014] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the utility model in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the P++ zone in the utility model;

[0016] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0017] Figure 3 Schematic diagram of the coverage between SE laser lines and metal grid lines; (a) is a schematic diagram of good coverage between metal grid lines and SE laser lines; (b) is a schematic diagram of poor coverage between metal grid lines and SE laser lines.

[0018] Description of Figure Numbers:

[0019] 1. Rectangular mark; 2. Positioning pattern; 3. SE laser line; 4. P++ area; 5. Metal grid line. DETAILED DESCRIPTION

[0020] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0021] like Figure 1 and Figure 2As shown, the utility model provides a SE-TOPCon battery, which includes, from top to bottom, a front electrode, a front silicon nitride anti-reflection film layer, an aluminum oxide passivation layer, a P++ region 4, a P+ layer, an N-type battery silicon wafer, a tunneling oxide layer, an ultra-thin silicon oxide layer, an N-type polysilicon thin film layer, a back silicon nitride anti-reflection film layer and a back electrode; the P++ region 4 includes four rectangular marks 1, four positioning patterns 2 and a plurality of SE laser lines 3, the plurality of SE laser lines 3 are engraved in parallel and at equal intervals on the front of the N-type battery silicon wafer, the four rectangular marks 1 are respectively engraved at the four corners of the front of the N-type battery silicon wafer, the four positioning patterns 2 are respectively engraved at the four corners of the front of the N-type battery silicon wafer and are respectively located on the inner sides of the four rectangular marks 1; the two vertically distributed rectangular marks 1 are distributed at both ends of the same SE laser line 3.

[0022] Of course, in specific implementation, the number of the rectangular marks 1 may also need to be set to six, eight, etc. It is sufficient to ensure that a pair of rectangular marks 1 are located on one SE laser line 3 .

[0023] In a specific implementation manner, the P++ area 4 of the SE-TOPCon battery is provided to include four rectangular marks 1, four positioning patterns 2 and multiple SE laser lines 3, the multiple SE laser lines 3 are engraved in parallel and at equal intervals on the front side of the N-type battery silicon wafer, the four rectangular marks 1 are respectively engraved at the four corners of the front side of the N-type battery silicon wafer, the four positioning patterns 2 are respectively engraved at the four corners of the front side of the N-type battery silicon wafer and are respectively located on the inner sides of the four rectangular marks 1, and the two vertically distributed rectangular marks 1 are distributed at both ends of the same SE laser line 3, so that when screen printing is performed, after the screen printing screen is initially positioned on the N-type battery silicon wafer by grabbing the four positioning patterns 2 of the P++ area 4, the staff continues to accurately position the screen pattern through the coverage of the four rectangular marks 1 and the multiple SE laser lines, thereby reducing the position deviation of the multiple metal grid lines 5 and the multiple SE laser lines 3 during screen printing of the SE-TOPCon battery, improving the short-circuit current, open-circuit voltage, filling factor and photoelectric conversion efficiency of the SE-TOPCon battery, and solving the problem of dark EL image after sintering of the SE-TOPCon battery.

[0024] Optionally, the shapes of the four positioning patterns 2 are all cross-shaped. Of course, the shape of the positioning pattern 2 can also be set to other shapes as required, such as square, oval, triangle, or five-pointed star, etc.

[0025] In a specific implementation manner, the engraving positions of the two vertically distributed positioning patterns 2 are both located between two adjacent SE laser lines 3 .

[0026] Optionally, the length of the plurality of SE laser lines 3 is the same as the width of the SE-TOPCon cell; and the etching width of each SE laser line 3 is 70-100 μm.

[0027] Optionally, the number of the SE laser lines 3 engraved in the P++ zone 4 is 154-200. Specifically, the number of SE laser lines 3 in the present invention can be adjusted according to the size of the SE-TOPCon battery or actual needs.

[0028] Optionally, the etching size of each rectangular mark 1 is 3-20 mm in length and 75-150 μm in width.

[0029] It should be noted that the etching width of the rectangular mark 1 is greater than the etching width of the SE laser line 3, which makes it easier for the staff to observe the coverage of the metal grid line 5 on the screen pattern on the rectangular mark 1 and multiple SE laser lines.

[0030] like Figure 3 As shown, if the coverage of the metal grid line 5 and the SE laser line 3 is as follows Figure 3 If the coverage of the metal grid line 5 and the SE laser line 3 is as shown in Figure (a), it proves that the coverage is good and the staff does not need to make manual adjustments; if the coverage of the metal grid line 5 and the SE laser line 3 is as shown in Figure (a), it proves that the coverage is good and the staff does not need to make manual adjustments; Figure 3 The situation shown in Figure (b) indicates that the coverage is poor and requires manual adjustment by the staff until the metal grid line 5 and the SE laser line 3 reach a higher coverage.

[0031] In order to verify the influence of the above scheme on the photoelectric conversion efficiency of the SE-TOPCon cell, multiple sets of data with different coverage conditions of the metal grid line 5 and the SE laser line 3 are set for experiments. The experimental data are shown in Table 1.

[0032] Table 1

[0033]

[0034]

[0035] As shown in Table 1, by changing the coverage between the metal grid line 5 and the SE laser line 3 and conducting multiple experiments, it can be proved that the higher the coverage between the metal grid line 5 and the SE laser line 3, the better the electrical parameters of the SE-TOPCon battery, such as the short-circuit current, open-circuit voltage and fill factor. The SE-TOPCon battery provided by the utility model increases four rectangular marks 1, observes the coverage between the metal grid line 5 and the four rectangular marks 1, and thus judges the coverage between the metal grid line 5 and the SE laser line 3, which makes it easier to achieve high coverage between the metal grid line 5 and the SE laser line 3, thereby improving the photoelectric conversion efficiency of the SE-TOPCon battery.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principle of the present invention, and these improvements and modifications should also be regarded as within the protection scope of the present invention.

Claims

1. A SE-TOPCon battery, characterized in that: The SE-TOPCon cell comprises, from top to bottom, a front electrode, a front silicon nitride anti-reflection film layer, an aluminum oxide passivation layer, a P++ region (4), a P+ layer, an N-type cell silicon wafer, a tunneling oxide layer, an ultra-thin silicon oxide layer, an N-type polysilicon thin film layer, a back silicon nitride anti-reflection film layer and a back electrode; The P++ area (4) comprises four rectangular marks (1), four positioning patterns (2) and a plurality of SE laser lines (3), wherein the plurality of SE laser lines (3) are engraved in parallel and at equal intervals on the front surface of the N-type battery silicon wafer, the four rectangular marks (1) are respectively engraved at the four corners of the front surface of the N-type battery silicon wafer, the four positioning patterns (2) are respectively engraved at the four corners of the front surface of the N-type battery silicon wafer and are respectively located on the inner sides of the four rectangular marks (1); the two vertically distributed rectangular marks (1) are distributed at both ends of the same SE laser line (3).

2. A SE-TOPCon battery according to claim 1, characterized in that: The shapes of the four positioning patterns (2) are all cross-shaped.

3. A SE-TOPCon battery according to claim 1, characterized in that: The length of the plurality of SE laser lines (3) is the same as the width of the SE-TOPCon cell; The etching width of each SE laser line (3) is 70-100 μm.

4. A SE-TOPCon battery according to claim 1, characterized in that: The number of the SE laser lines (3) engraved in the P++ zone (4) is 154-200.

5. A SE-TOPCon battery according to claim 1, characterized in that: The etching dimensions of each rectangular mark (1) are 3-20 mm in length and 75-150 μm in width.

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