Multi-beam laser-induced sintering method and device

Abstract

According to the multi-beam laser-induced sintering method, a first electrode is arranged on the first surface of a photovoltaic cell to make contact with a first grid line, a second electrode is arranged on the second surface or the first surface of the photovoltaic cell to make contact with a second grid line, and the first electrode and the second electrode are connected with the positive electrode and the negative electrode of a power source respectively to apply reverse bias voltage to the cell; and a plurality of split light spots are adopted to simultaneously scan different scanning areas of the photovoltaic cell for laser-induced sintering. The scanning area is divided into a plurality of strip-shaped blocks in the direction perpendicular to the extending direction of the first electrode, one light splitting light spot corresponds to one scanning area for laser scanning, and different light splitting light spots are different in power density. By means of the method, the laser-induced machining effects of the areas close to and away from the first electrode tend to be consistent; the situation that multiple split light irradiates the same grid line at the same time to reduce the influence of generated large current on the grid line and a cell substrate is avoided, and the laser-induced sintering effect is improved; and the bad EL black edge caused by reverse breakdown and over-processing of the edge area of the battery piece is avoided.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a multi-spectral laser induced sintering method and device. Background Art

[0002] Laser-induced sintering (LIF) technology uses lasers to excite the carriers of photovoltaic cells, and directs them to flow and form a loop under the action of the reverse bias of an external electric field. When the loop current flows through the interface between the gate electrode metal and the silicon wafer, a significant thermal effect is generated due to the large contact resistance between the gate electrode metal and the silicon wafer. The heat can further promote the mutual diffusion of the gate electrode metal and the silicon wafer, thereby obtaining a better metallization contact effect and good passivation effect on the silicon wafer surface, which increases the opening voltage by more than 5mV and the cell efficiency by more than 0.3%.

[0003] To improve the efficiency of laser-induced sintering (LIS), multi-beam splitting can be used. Using different beam splitting spots to simultaneously scan different areas of a photovoltaic cell, covering all areas to be processed, this can significantly improve the efficiency of LIS. However, the applicant discovered that when using multi-beam splitting for LIS, the LIS results differed between different areas of the photovoltaic cell. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention provides a multi-spectral laser induced sintering method and device.

[0005] On the one hand, the present invention provides a method for multi-spectral laser induced sintering, wherein a first electrode is arranged on the first surface of a photovoltaic cell and contacts the first grid line of the first surface, and a second electrode is arranged on the second surface or the first surface of the photovoltaic cell and contacts the second grid line of the photovoltaic cell, the first electrode and the second electrode are respectively connected to the positive and negative poles of a power supply, and a reverse bias is applied to the photovoltaic cell, and a multi-spectral light spot is used to simultaneously scan different scanning areas of the photovoltaic cell to perform laser induced sintering; wherein the scanning area is divided into a plurality of strips and blocks along an extension direction perpendicular to the first electrode, and a spectroscopic light spot performs laser scanning on one scanning area, and the power density of different spectroscopic light spots is different; the first grid line and the second grid line have opposite polarities.

[0006] As a further improvement of the present invention, the power density of the light splitting spot close to the first electrode is smaller than the power density of the light splitting spot far from the first electrode.

[0007] As a further improvement of the present invention, the number of the light splitting spots is two, and the ratio of the power density of a first light splitting spot close to the first electrode to the power density of a second light splitting spot far from the first electrode is greater than 50% and less than 100%.

[0008] As a further improvement of the present invention, the power density of the light splitting spot close to the edge of the cell is smaller than the power density of the light splitting spot far from the edge of the cell.

[0009] As a further improvement of the present invention, the number of the light splitting spots is two, and the power density of the second light splitting spot close to the edge of the cell is reduced by 0-50% compared with the power density of the first light splitting spot far from the edge of the cell.

[0010] As a further improvement of the present invention, the scanning direction of the multi-beam spot is perpendicular to the extension direction of the first electrode or parallel to the extension direction of the first electrode.

[0011] As a further improvement of the present invention, different splitting light spots do not scan the same fine grid at the same time.

[0012] As a further improvement of the present invention, when the photovoltaic cell is a photovoltaic cell with double-sided electrodes or a photovoltaic cell with single-sided electrodes without a main grid, the first electrode is arranged perpendicular to the extension direction of the fine grid; when the photovoltaic cell is a photovoltaic cell with a single-sided electrode with a main grid, the first electrode is arranged perpendicular to the extension direction of the main grid.

[0013] On the other hand, the present invention provides a multi-beam splitting laser induced sintering device for implementing the aforementioned method, comprising a laser generator, a quarter wave plate, a beam splitter, a galvanometer and a focusing mirror arranged in sequence along the laser light path, and controlling the power ratio of the beam splitting spot by the quarter wave plate.

[0014] On the other hand, the present invention provides a multi-spectral laser induced sintering method, wherein a first electrode is arranged on the first surface of the photovoltaic cell and contacts the first grid line of the first surface, and a second electrode is arranged on the second surface or the first surface of the photovoltaic cell and contacts the second grid line of the photovoltaic cell. The first electrode and the second electrode are respectively connected to the positive and negative poles of the power supply, and a reverse bias is applied to the photovoltaic cell. A multi-spectral light spot is used to simultaneously scan different scanning areas of the photovoltaic cell to perform laser induced sintering; wherein different spectroscopic light spots do not scan the same fine grid at the same time; and the polarities of the first grid line and the second grid line are opposite.

[0015] As a further improvement of the present invention, the scanning area of ​​the multi-beam splitting light spot is divided into a plurality of strips and blocks along the extending direction of the first electrode, and one beam splitting light spot performs laser scanning on one scanning area.

[0016] As a further improvement of the present invention, the scanning area of ​​the multi-beam splitting spot is divided into a plurality of strips and blocks along a direction perpendicular to the extension direction of the first electrode, and one beam splitting spot performs laser scanning on one scanning area.

[0017] As a further improvement of the present invention, different light splitting spots have a certain distance between them in the extending direction of the first electrode.

[0018] As a further improvement of the present invention, the distance between adjacent splitting light spots in the extension direction of the first electrode is greater than a splitting light spot size.

[0019] As a further improvement of the present invention, when the photovoltaic cell is a photovoltaic cell with double-sided electrodes or a photovoltaic cell with single-sided electrodes without a main grid, the first electrode is arranged perpendicular to the extension direction of the fine grid; when the photovoltaic cell is a photovoltaic cell with a single-sided electrode with a main grid, the first electrode is arranged perpendicular to the extension direction of the main grid.

[0020] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0021] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0022] The present invention performs laser induced sintering by arranging multiple splitting modes, and can set different splitting power densities according to the laser induced sintering effects of different areas of the photovoltaic cell.

[0023] When the present invention adopts multi-spectral laser induced sintering, the power density of the spectrum away from the first electrode is set to be greater than the power density of the spectrum close to the first electrode, thereby enhancing the current density of the area away from the electrode, so that the laser induced processing effects of the area close to the first electrode and the scanning area away from the first electrode tend to be consistent.

[0024] When the present invention adopts multi-spectral laser induced sintering, the laser power density of the spectroscopic spot close to the edge of the cell is set to be lower than the power density of the spectroscopic spot far from the edge of the cell, thereby avoiding reverse breakdown in the edge area of ​​the photovoltaic cell and EL black edge defects caused by over-processing.

[0025] When the present invention adopts multi-beam splitting for laser induced sintering, the multi-beam splitting is arranged at a certain distance perpendicular to the extension direction of the fine grid electrode, thereby avoiding the multi-beam splitting from irradiating the same grid line at the same time, reducing the impact of the generated large current on the grid line and the battery substrate, and improving the laser induced sintering effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1Schematic diagram of a multi-spectral laser-induced sintering method for a photovoltaic cell with double-sided electrodes according to one embodiment.

[0028] Figure 2 Schematic diagram of a multi-spectral laser-induced sintering method for a photovoltaic cell with a single-sided electrode according to one embodiment.

[0029] Figure 3 A schematic diagram of a multi-spectral laser induced sintering method according to an embodiment.

[0030] Figure 4 A schematic diagram of a multi-spectral laser induced sintering method according to an embodiment.

[0031] Figure 5 Schematic diagram of a multi-spectral laser device according to one embodiment.

[0032] Figure 6 A schematic diagram of a multi-spectral laser induced sintering method according to an embodiment.

[0033] Figure 7 A schematic diagram of a multi-spectral laser induced sintering method according to an embodiment.

[0034] In all the drawings, the same figure marks represent the same technical features, specifically: photovoltaic cell 1, fine grid 11, first electrode 2, splitter spot 3, second electrode 4, first splitter spot 31, second splitter spot 32, laser generator 101, 1 / 4 wave plate 102, splitter 103, galvanometer 104, stage 105, first scanning area A, second scanning area B. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0036] The present invention provides a multi-beam laser induced sintering method, which applies a reverse bias voltage to a photovoltaic cell and uses a multi-beam spot to simultaneously scan different areas of the photovoltaic cell to perform laser induced sintering.

[0037] The multi-spectral laser-induced sintering method of the present invention is applied to photovoltaic cells with double-sided electrodes or single-sided electrodes. Double-sided electrode photovoltaic cells refer to photovoltaic cells with grid lines for carrier extraction on both the front and back sides. Single-sided electrode photovoltaic cells refer to photovoltaic cells with grid lines for carrier extraction on the back sides, which are sintered or pre-sintered grid lines. The photovoltaic cell includes two surfaces arranged opposite to each other, a first surface and a second surface, wherein the first surface can be the front or the back, and correspondingly, the second surface can be the back or the front. The front side refers to the light-receiving side of the photovoltaic cell, and the back side refers to the backlight side of the photovoltaic cell.

[0038] See also Figure 1 and Figure 2 The multi-spectral laser induced sintering method of the present invention is to set a first electrode 2 on the first surface of the photovoltaic cell 1, which is in contact with the first grid line of the first surface; set a second electrode 4 on the second surface or the first surface of the photovoltaic cell 1, which is in contact with the second grid line of the photovoltaic cell; the first electrode 2 and the second electrode 4 are respectively connected to the positive and negative poles of the power supply, and a reverse bias is applied to the photovoltaic cell 1; and a multi-spectral spot 3 is used to simultaneously scan different areas of the photovoltaic cell to perform laser induced sintering. Figure 1 and Figure 2 In FIG, different scanning areas are marked with dotted lines.

[0039] Wherein, when laser induced sintering is performed, the spectroscopic spot can scan the first surface or the second surface. In the present invention, the first surface can be the front or the back, and correspondingly, the second surface can be the back or the front. Preferably, when laser induced sintering is performed on a photovoltaic cell with double-sided electrodes, the first surface is the front and the spectroscopic spot scans the first surface; when laser induced sintering is performed on a photovoltaic cell with single-sided electrodes, the first surface is the back and the spectroscopic spot scans the first surface. The polarity of the first grid line and the second grid line is opposite, that is, when the first grid line is set in the P area of ​​the photovoltaic cell, the second grid line is set in the N area of ​​the photovoltaic cell.

[0040] See also Figure 1 , a schematic diagram of multi-spectral laser-induced sintering of a double-sided electrode photovoltaic cell. For a double-sided electrode photovoltaic cell, the first electrode 2 contacts the gridlines on the first surface of the photovoltaic cell 1 (the first gridlines), and the second electrode (not shown) contacts the gridlines on the second surface of the photovoltaic cell 1 (the second gridlines).

[0041] See also Figure 2 , is a schematic diagram of multi-beam laser induced sintering of a photovoltaic cell with a single-sided electrode. For a photovoltaic cell with a single-sided electrode, the first electrode 2 contacts the first grid line on the first surface of the photovoltaic cell 1, and the second electrode 4 contacts the second grid line on the first surface of the photovoltaic cell 1.

[0042] See also Figure 1 and Figure 2 The first electrode 2 of the present invention is preferably a strip electrode. It should be noted that the strip electrode here means that the outer contour of the electrode when projected on the horizontal plane (projected on the surface of the photovoltaic cell) is a strip. The length direction of the first electrode 2 is the extension direction of the first electrode 2.

[0043] For photovoltaic cells with double-sided electrodes, the structure of the first electrode can be a probe row structure (i.e., a plurality of probes spaced approximately in one direction are connected below a probe holder, and the plurality of probes are in contact with the cell), or an elastic conductive wire structure, or an elongated elastic electrode sheet structure (the electrode sheet and the photovoltaic cell can be in surface contact). The elastic probe row structure is preferred. The second electrode can be a strip electrode similar to the first electrode, or a conductive plate, or a conductive column.

[0044] For photovoltaic cells with single-sided electrodes, the structure of the first electrode is preferably a probe row structure, and the structure of the second electrode is preferably a probe row structure. It should be noted that the probes of the first electrode and the second electrode can be set on the same probe holder or two probe holders. Figure 2 Schematic diagram of the arrangement of the first electrode 2 and the second electrode 4 on the same probe holder is given in FIG. The length direction of the probe holder where the first electrode 2 is located is the extending direction of the first electrode 2 .

[0045] In some embodiments of the present invention, the scanning area of ​​the multi-beam splitting spot is divided into multiple strips and blocks along a direction perpendicular to the extension direction of the first electrode, and each beam splitting spot performs laser scanning on each scanning area. The laser power density of the beam splitting spot closer to the first electrode is lower than the power density of the beam splitting spot farther from the first electrode.

[0046] For a photovoltaic cell with double-sided electrodes, the first electrode is arranged perpendicular to the extension direction of the fine grid, such as Figure 1 When a main grid is provided, the first electrode is preferably arranged on the main grid.

[0047] For a photovoltaic cell with a single-sided electrode, when there is no main grid, the first electrode is arranged perpendicular to the extension direction of the fine grid, such as Figure 2 When a main grid is provided, the first electrode is arranged perpendicular to the extension direction of the main grid.

[0048] The following describes the laser scanning method for double-sided electrode photovoltaic cells, assuming that the number of split beams is two and the corresponding scanning areas are two. Figure 3 and Figure 4, is a schematic diagram of the multi-beam laser-induced sintering processing method, with two scanning areas indicated by dashed lines. The first electrode 2 contacts the grid lines perpendicular to the extension direction of the fine grid. The scanning area close to the first electrode 2 is the first scanning area A, and the corresponding beam splitting spot is the first beam splitting spot 31. The scanning area away from the first electrode 2 is the second scanning area B, and the corresponding beam splitting spot is the second beam splitting spot 32. The power density of the first beam splitting spot 31 is less than the power density of the second beam splitting spot 32.

[0049] As a specific implementation, the power density ratio of the first split light spot to the second split light spot is greater than 50% and less than 100%. Specifically, it can be a point value or a range value therebetween.

[0050] The split light spot of the present invention refers to a light spot formed on a photovoltaic cell when a laser beam emitted by a laser generating device is split into multiple beams by an optical device and the multiple laser beams are irradiated.

[0051] When multi-spectral laser induced sintering is performed, since multiple spectra act on the photovoltaic cell at the same time, the voltages obtained by the spectra spots close to the first electrode and those far away from the first electrode are inconsistent. Specifically, the spectra spots far away from the first electrode have a longer power-on current transmission path, resulting in a larger power-on voltage loss, which in turn leads to a smaller divided voltage. In an embodiment of the present invention, by setting the power density of the spectra spots close to the first electrode to be lower than the power density of the spectra spots far away from the first electrode, the current density in the area far away from the electrode is enhanced, so that the laser induced processing effects of the area close to the first electrode and the scanning area far away from the first electrode tend to be consistent.

[0052] See also Figure 3 The first splitting light spot 31 and the second splitting light spot 32 can scan the first scanning area A and the second scanning area B parallel to the extension direction of the first electrode 2. Specifically, the first splitting light spot 31 and the second splitting light spot 32 start from one side of the first scanning area A and the second scanning area B, scan from the upper end to the lower end, and then move to the other side by the spacing of one light spot, scanning from the upper end to the lower end or from the lower end to the upper end, and continue until the scanning of all corresponding areas is completed.

[0053] See also Figure 4 The first splitting light spot 31 and the second splitting light spot 32 can scan the first scanning area A and the second scanning area B perpendicular to the extension direction of the first electrode 2. Specifically, the first splitting light spot 31 and the second splitting light spot 32 start from the upper end of the first scanning area A and the second scanning area B, scan from one side to the other side, and then move to the lower end by the spacing of one light spot, scan from the other side to one side, or scan from one side to the other side, and continue until all corresponding areas are scanned.

[0054] In actual industrial production, the square resistance of the edge area of ​​photovoltaic cells is higher than that of the middle area due to process reasons. For example, the high-temperature diffusion process will lead to a lower doping concentration in the edge area, and the wet etching process will cause slight over-corrosion in the edge area. These processes will lead to higher square resistance in the edge area. When the existing technology uses multi-spectral laser induced sintering, the power density of the spectroscopic spot is the same for the edge area and the middle area of ​​the photovoltaic cell. Since the depletion layer width in the high square resistance area of ​​the photovoltaic cell is large and the carrier mobility is high, when the laser power density increases, the electric field strength in the depletion layer is more likely to reach a level that allows the carriers to obtain sufficient energy to induce collision ionization, thereby causing avalanche breakdown. Therefore, the edge area of ​​the photovoltaic cell is not suitable for laser induced sintering treatment using high power density.

[0055] Based on this, in some other embodiments, the scanning area of ​​the multi-beam splitting spot is divided into multiple strips and blocks along the direction perpendicular to the extension of the first electrode, and each beam splitting spot performs laser scanning on each scanning area. The laser power density of the beam splitting spot near the edge of the cell is lower than the power density of the beam splitting spot far from the edge of the cell. It will be understood that the edge of the photovoltaic cell described in this embodiment refers to the edge perpendicular to the extension direction of the first electrode.

[0056] In this embodiment, the arrangement of the first electrode and the second electrode, the scanning direction of the light splitting spot, etc. are the same as those in the previous embodiment. The difference lies in the power of the light splitting spot. Figures 1 to 4 As shown, the second scanning area B is the area near the edge of the cell, and is scanned by the second beam splitting spot 32 for laser-induced sintering. The first scanning area A is the area away from the edge of the cell, and is scanned by the first beam splitting spot 31 for laser-induced sintering. In this embodiment, the power density of the second beam splitting spot 32 is lower than the power density of the first beam splitting spot 31. Specifically, the power density of the second beam splitting spot is reduced by 0% to 50% compared to the power density of the first beam splitting spot. More specifically, the power density is greater than 0 and less than 50%. More specifically, it can be a point value or a range of values.

[0057] The technical solution of this embodiment can avoid reverse breakdown in the edge area of ​​the photovoltaic cell and EL black edge defects caused by over-processing.

[0058] Another aspect of the present invention provides a multi-spectral laser induced sintering device, see Figure 5, is a schematic diagram of the structure of a multi-beam splitting laser-induced sintering device, comprising a laser generator 101, a quarter-wave plate 102, a beam splitter 103, a galvanometer 104, and a focusing mirror (not shown) arranged sequentially along the laser optical path. The quarter-wave plate 102 precisely controls the power ratio of the beam splitting spot, thereby laser-induced sintering the solar cell 1 on the stage 105. It should be noted that the multi-beam splitting laser-induced sintering device also includes a first electrode, a second electrode, etc., which are all existing technologies and can be configured with reference to the existing technologies.

[0059] In another aspect, the present invention provides a multi-beam laser-induced sintering method, which applies a reverse bias voltage to a photovoltaic cell and uses multiple beamspots to simultaneously scan different areas of the photovoltaic cell for laser-induced sintering. The scanning area of ​​the multi-beam laser is divided into multiple strips, with each beam spot corresponding to each scanning area. Furthermore, different beamspots do not simultaneously scan the same fine grid.

[0060] When using multiple beam splitting spots for laser-induced sintering, when multiple beam splitting spots simultaneously illuminate the same grid line, the current generated by the laser-induced sintering simultaneously flows through this grid line. When multiple beam splitting spots act on the same grid line simultaneously, the current carried by the grid line is the sum of the currents generated by the multiple beam splitting spots during laser-induced sintering, which will increase power loss on the grid line and the heat generated will affect the grid line or the battery substrate. This embodiment prevents multiple beam splitting spots from irradiating the same fine grid at the same time by providing a certain spacing perpendicular to the extension direction of the fine grid. This reduces the impact of the generated large current on the grid line and the battery substrate, and improves the laser-induced sintering effect.

[0061] The first electrode and the second electrode and their configuration are the same as those in the previous embodiment and will not be described in detail here.

[0062] For double-sided electrode photovoltaic cells and single-sided electrode photovoltaic cells without main grid, different splitting spots do not scan the same fine grid at the same time.

[0063] In this case, in addition to being located in different subareas, the splitting light spots also have a certain distance in the extension direction of the first electrode. Specifically, the distance between adjacent splitting light spots in the extension direction of the first electrode is greater than one splitting light spot size.

[0064] See also Figure 6 , is a schematic diagram of multi-spectral laser induced sintering in one embodiment, specifically, Figure 6This is a schematic diagram of multi-beam splitting laser-induced sintering of a photovoltaic cell with double-sided electrodes. As a specific embodiment, multiple scanning areas are arranged perpendicular to the extension direction of the first electrode. In the figure, two scanning areas are shown with dotted lines. The first scanning area A and the second scanning area B are scanned using the first beam splitting spot 31 and the second beam splitting spot 32, respectively. The first beam splitting spot 31 and the second beam splitting spot 32 do not scan the same fine grid at the same time. The specific scanning method is described in the aforementioned embodiment. Scanning can be performed perpendicular to the fine grid or parallel to the fine grid.

[0065] See also Figure 7 , is a schematic diagram of laser induced sintering using multi-spectral scanning in one embodiment. As a specific embodiment, the scanning areas are multiple and are arranged along the extension direction of the first electrode. In this embodiment, since the scanning areas are arranged along the extension direction of the first electrode, the spectroscopic spots themselves have a certain spacing in the electrode extension direction, and the same fine grid will not be scanned at the same time. In the figure, two scanning areas are shown by dotted lines. The first scanning area A and the second scanning area B are scanned using the first spectroscopic spot 31 and the second spectroscopic spot 32, respectively. The specific scanning method is described with reference to the aforementioned embodiment. Scanning can be performed perpendicular to the fine grid direction or parallel to the fine grid direction.

[0066] It should be noted that since the first splitting light spot and the second splitting light spot have a certain distance in the extension direction of the first electrode, a certain scanning margin can be retained at the upper and lower ends during scanning, so that when the first splitting light spot and the second splitting light spot are scanned at the same time, their respective scanning areas are ensured to be no smaller than the intended scanning area, and any light spot can be scanned from one edge of the photovoltaic cell to the other.

[0067] In another aspect, the present invention provides a multi-beam splitting laser-induced sintering method that combines the three aforementioned methods. The scanning area of ​​the multi-beam splitting spot is divided into multiple strips perpendicular to the extension direction of the first electrode. Each beam splitting spot performs laser scanning on each scanning area. The laser power densities of the different beam splitting spots differ, and the different beam splitting spots do not simultaneously scan the same fine grid.

[0068] It should be noted that the sum of the scanning areas of the multi-beam spot described in the present invention is the area to be processed. This area to be processed can be a partial area of ​​a photovoltaic cell, such as half of the photovoltaic cell. For example, when a photovoltaic cell is processed at two stations, half of the cell is processed first at the first station, and then the other half is processed at the other station.

[0069] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A multi-spectral laser induced sintering method, characterized in that: A first electrode is provided on a first surface of the photovoltaic cell, contacting a first grid line on the first surface; a second electrode is provided on a second surface or the first surface of the photovoltaic cell, contacting a second grid line on the photovoltaic cell; the first electrode and the second electrode are connected to a positive and negative pole of a power supply, respectively, to apply a reverse bias to the photovoltaic cell; and a multi-beam spot is used to simultaneously scan different scanning areas of the photovoltaic cell to perform laser-induced sintering. The scanning area is divided into a plurality of strips and blocks along a direction perpendicular to the extension direction of the first electrode, and one splitting spot performs laser scanning corresponding to one scanning area, and different splitting spots have different power densities; The first gate line and the second gate line have opposite polarities.

2. The multi-spectral laser induced sintering method according to claim 1, characterized in that: The power density of the light splitting spot close to the first electrode is smaller than the power density of the light splitting spot far from the first electrode.

3. The multi-spectral laser induced sintering method according to claim 2, characterized in that: The number of the light splitting spots is two, and the ratio of the power density of a first light splitting spot close to the first electrode to the power density of a second light splitting spot far from the first electrode is greater than 50% and less than 100%.

4. The multi-spectral laser induced sintering method according to claim 1, characterized in that: The power density of the light splitting spot close to the edge of the photovoltaic cell is smaller than the power density of the light splitting spot far from the edge of the cell.

5. The multi-spectral laser induced sintering method according to claim 4, characterized in that: The number of the light splitting spots is two, and the power density of the second light splitting spot close to the edge of the battery cell is reduced by 0-50% compared with the power density of the first light splitting spot far from the edge of the battery cell.

6. The multi-spectral laser induced sintering method according to claim 1, characterized in that: The scanning direction of the multi-beam spot is perpendicular to the extending direction of the first electrode or parallel to the extending direction of the first electrode.

7. The multi-spectral laser induced sintering method according to claim 1, characterized in that: Different spectral spots scan the same fine grid at different times.

8. The multi-spectral laser induced sintering method according to any one of claims 1 to 7, characterized in that: When the photovoltaic cell is a photovoltaic cell with double-sided electrodes or a photovoltaic cell with single-sided electrodes without a main grid, the first electrode is arranged perpendicular to the extension direction of the fine grid; when the photovoltaic cell is a photovoltaic cell with single-sided electrodes with a main grid, the first electrode is arranged perpendicular to the extension direction of the main grid.

9. A multi-spectral laser induced sintering device for implementing the method according to any one of claims 1 to 8, characterized in that: The invention comprises a laser generator, a quarter wave plate, a beam splitter, a galvanometer and a focusing mirror which are sequentially arranged along the laser optical path, and the power ratio of the beam splitting spot is controlled by the quarter wave plate.

10. A multi-spectral laser induced sintering method, characterized in that: A first electrode is provided on a first surface of the photovoltaic cell, contacting a first grid line on the first surface; a second electrode is provided on a second surface or the first surface of the photovoltaic cell, contacting a second grid line on the photovoltaic cell; the first electrode and the second electrode are connected to a positive and negative pole of a power supply, respectively, to apply a reverse bias to the photovoltaic cell; and a multi-beam spot is used to simultaneously scan different scanning areas of the photovoltaic cell to perform laser-induced sintering. Among them, different spectroscopic spots do not scan the same fine grid at the same time; The first gate line and the second gate line have opposite polarities.

11. The multi-spectral laser induced sintering method according to claim 10, characterized in that: The scanning area of ​​the multi-beam splitting light spot is divided into a plurality of strips and blocks along the extending direction of the first electrode, and one beam splitting light spot performs laser scanning corresponding to one of the scanning areas.

12. The multi-spectral laser induced sintering method according to claim 10, characterized in that: The scanning area of ​​the multi-beam splitting light spot is divided into a plurality of strips and blocks along a direction perpendicular to the extension direction of the first electrode, and one beam splitting light spot performs laser scanning on one scanning area.

13. The multi-spectral laser induced sintering method according to claim 12, characterized in that: Different light splitting spots have a certain distance between them in the extending direction of the first electrode.

14. The multi-spectral laser induced sintering method according to claim 13, characterized in that: The distance between adjacent splitting light spots in the extending direction of the first electrode is greater than a splitting light spot size.

15. The multi-spectral laser induced sintering method according to any one of claims 10 to 14, characterized in that: When the photovoltaic cell is a photovoltaic cell with double-sided electrodes or a photovoltaic cell with single-sided electrodes without a main grid, the first electrode is arranged perpendicular to the extension direction of the fine grid; when the photovoltaic cell is a photovoltaic cell with single-sided electrodes with a main grid, the first electrode is arranged perpendicular to the extension direction of the main grid.

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