A laser sintering method, a processing method and a battery piece of a battery piece

Abstract

The application relates to the technical field of battery piece manufacturing, and provides a laser sintering method of a battery piece, a processing method and the battery piece. The laser sintering method of the battery piece comprises the following steps: placing a battery piece to be sintered on a laser device, setting a laser scanning line segment of the laser device to comprise a plurality of real segments and a plurality of virtual segments, and alternately arranging the real segments and the virtual segments, wherein the real segment is a segment with laser scanning, and the virtual segment is a segment without laser scanning; and controlling the laser device to scan the battery piece according to the laser scanning line segment. The laser sintering method of the battery piece provided by the application sets the line segment of laser scanning as the virtual segment and the real segment to be alternated, the segment of the virtual segment is not scanned by laser when the battery piece is scanned, the grid line and the local silicon piece in the battery piece form contact, the area of metal combination is reduced, and the conversion efficiency of the battery piece is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cell manufacturing, and in particular to a laser sintering method, a processing method and a solar cell for a solar cell. BACKGROUND

[0002] Laser-enhanced contact optimization (LECO) is a commonly used laser sintering technology. In the processing of TOPcon solar cells, laser sintering is generally used in the next process after the blue film solar cell front surface is printed with LECO paste and sintered.

[0003] In the prior art, a bias voltage of about 10V is generally applied to the solar cell during laser sintering, and a high-intensity laser is used to continuously scan the solar cell. Under the action of the local current generated on the grid line of the solar cell and the thermal effect of the laser, the temperature near the grid line reaches about 840 degrees Celsius, causing silver and silicon to diffuse with each other to obtain better contact and reduce the contact resistivity, so as to improve the conversion efficiency of the solar cell.

[0004] However, in the prior art, laser sintering causes all grid lines in the solar cell to form contact with the silicon wafer, increasing the metal area recombination area on the solar cell and easily affecting the improvement of the conversion efficiency of the solar cell. SUMMARY

[0005] The present application provides a laser sintering method, a processing method and a solar cell for a solar cell to solve the technical problem that in the prior art, laser sintering causes all grid lines in the solar cell to form contact with the silicon wafer, increasing the metal area recombination area on the solar cell and easily affecting the improvement of the conversion efficiency of the solar cell.

[0006] To solve the above problems, the present application provides a laser sintering method for a solar cell, which comprises:

[0007] Placing a solar cell to be sintered in a laser device, and setting a laser scanning line segment of the laser device to include a plurality of real segments and a plurality of virtual segments, and the real segments and the virtual segments are arranged alternately, wherein the real segment is a segment with laser scanning, and the virtual segment is a segment without laser scanning;

[0008] Controlling the laser device to scan the solar cell according to the laser scanning line segment.

[0009] In some embodiments, the real segment includes a plurality of laser spots arranged linearly.

[0010] In some embodiments, the lengths of the plurality of real segments in the laser scanning line segment are the same, and the lengths of the plurality of virtual segments are the same.

[0011] In some embodiments, before controlling the laser device to scan the battery piece according to the laser scanning line segment, the sintering method of the battery piece further comprises:

[0012] Adjusting the solid-void ratio of the laser scanning line segment, the solid-void ratio being the ratio of the length of the solid segment and the length of the void segment.

[0013] In some embodiments, the adjustment range of the solid-void ratio is 0%-80%.

[0014] In some embodiments, the solid segment in the laser scanning line segment comprises M laser spots, and the minimum adjustment amount of the solid segment is 1 / M.

[0015] In some embodiments, when controlling the laser device to scan the battery piece, a plurality of laser scanning line segments are formed;

[0016] The plurality of laser scanning line segments are arranged at equal intervals in the direction perpendicular to the laser scanning.

[0017] The application also provides a battery piece processing method, which comprises:

[0018] Using LECO paste to print the sub-grid on the front surface of the blue film piece of the battery piece, and sintering;

[0019] Using any one of the above-mentioned laser sintering methods of the battery piece to sinter the battery piece.

[0020] The application also provides a battery piece obtained by using the battery piece processing method.

[0021] The application has the following beneficial effects: the laser sintering method of the battery piece provided by the application comprises: placing the battery piece to be sintered on a laser device, setting the laser scanning line segment of the laser device to comprise a plurality of solid segments and a plurality of void segments, and arranging the solid segments and the void segments alternately; and then controlling the laser device to scan the battery piece according to the laser scanning line segment. By setting the scanning line segment to be the scanning line segment with the solid segments and the void segments arranged alternately, since the solid segments in the scanning line segment are the segments with laser scanning, and the void segments are the segments without laser scanning, after laser scanning of the battery piece, the grid lines and the silicon piece in the battery piece only form contact locally, thereby reducing the area of metal combination and improving the conversion efficiency of the battery piece.

[0022] Before controlling the laser device to scan the battery piece according to the laser scanning line segment, the length of the solid segment can be adjusted by adjusting the number of laser spots of the solid segment in the laser scanning line segment, and then the solid-void ratio of the laser scanning line segment can be adjusted to find a suitable solid-void ratio according to the production line conditions to maximize the conversion efficiency of the battery piece. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0024] Figure 1 This is a flowchart of a laser sintering method for a battery cell provided in an embodiment of this application;

[0025] Figure 2 This is a schematic diagram of the structure of several laser scanning segments in the laser sintering method for a battery cell provided in an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of the structure of the laser scanning line segment in the laser sintering method for a battery cell provided in an embodiment of this application;

[0027] Figure 4 This is a flowchart of a laser sintering method for a battery cell provided in another embodiment of this application;

[0028] Figure 5 This is an image of a laser scanning line segment irradiating a battery cell in a laser sintering method for a battery cell provided in an embodiment of this application;

[0029] Figure 6 This is an image of a laser scanning line segment irradiating the battery cell in a laser sintering method for a battery cell provided in another embodiment of this application. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] Referring to Figure 1 The application provides a laser sintering method of a battery piece, which can be used in the processing of a TOPcon battery piece. After the LECO paste is used to print the sub-grid on the front surface of the blue film piece of the battery piece and sintering, the laser sintering method of the battery piece provided by the application can be used to sinter the battery piece.

[0033] The laser sintering method of the battery piece provided by the application can include the following steps:

[0034] In step S10, the battery piece to be sintered is placed in the laser equipment, and the laser scanning line segment of the laser equipment is set to include a plurality of real segments and a plurality of virtual segments, and the real segments and the virtual segments are arranged alternately, wherein the real segment is a segment with laser scanning, and the virtual segment is a segment without laser scanning.

[0035] In this step, the battery piece to be sintered is placed in the laser equipment, wherein the battery piece to be sintered refers to the battery piece after the LECO paste is used to print the sub-grid on the front surface of the blue film piece and sintering, which is further subjected to laser sintering.

[0036] The laser sintering of the battery piece can be completed by controlling the laser equipment to emit the laser scanning line segment to scan the battery piece. It can be understood that the laser equipment includes a laser scanning structure, and the laser scanning structure includes a plurality of scanning units, and the scanning unit is used to emit the laser scanning line segment. A plurality of scanning units are arranged at equal intervals along the length direction perpendicular to the laser scanning line segment, as shown in FIG. 1. Figure 2 Correspondingly, when the laser equipment is controlled to scan the battery piece, a plurality of laser scanning line segments can be controlled to scan the battery piece, and the plurality of laser scanning line segments are arranged at equal intervals in the length direction perpendicular to the laser scanning line segment.

[0037] Since the real segment in the laser scanning line segment is a segment with laser scanning, and the virtual segment is a segment without laser scanning, and the real segment and the virtual segment are arranged alternately, it can be understood that the virtual segment is the segment between the adjacent two real segments, as shown in FIG. 2. Figure 3 For example, in some embodiments, the real segment in the laser scanning line segment can include a plurality of linearly arranged laser spots, that is, a plurality of laser spots arranged in a line segment to form a real segment, as shown in FIG. 3 and FIG. 4. Figure 5 Figure 6 It should be noted that the plurality of linearly arranged laser spots in the real segment can be tangent or intersected between the adjacent two laser spots, so that the length of the real segment in the laser scanning line segment can be adjusted by adjusting the number of spots in the real segment or the intersected area between the adjacent two laser spots.

[0038] ​By controlling the position of the laser spots in the laser scanning line segment, the laser scanning line segment of the laser device can be set to include a plurality of real segments and a plurality of virtual segments, and the real segments and the virtual segments are arranged alternately, for example, the laser spots arranged linearly in the scanning unit are arranged at intervals, and the interval segments are virtual segments.

[0039] Of course, in some embodiments, the lengths of the plurality of real segments in the laser scanning line segment are the same, and the lengths of the plurality of virtual segments are the same. This facilitates the setting of the laser scanning line segment and guarantees the uniformity of each laser scanning line segment for sintering of the battery piece.

[0040] Step S20, controlling the laser device to scan the battery piece according to the laser scanning line segment.

[0041] After the laser scanning line segment of the laser device is set, the laser device is started to scan the battery piece according to the set laser scanning line segment. It can be understood that before the laser device is started to scan the battery piece, a bias voltage is loaded to the battery piece, for example, the bias voltage loaded to the battery piece can be about 10V, but is not limited thereto.

[0042] The laser sintering method for the battery piece provided in the above embodiments of the present application sets the laser scanning line segment for scanning the battery piece as a scanning line segment in which real segments and virtual segments are arranged alternately, so that after the battery piece is scanned by laser, the grid lines and the silicon piece in the battery piece only form contact locally, thereby reducing the area of metal recombination and improving the conversion efficiency of the battery piece. It should be noted that the area of metal recombination refers to the area in which the paste and the silicon piece form ohmic contact, and this area increases recombination by destroying the passivation layer. The area with metal does not necessarily cause recombination. During laser sintering, the place scanned by laser forms a carrier passing through, local sintering (temperature rise), and the glass in the sintering process destroys the passivation layer to form ohmic contact, and the recombination increases. The area that is not scanned will not be destroyed basically. Therefore, after the battery piece is scanned by laser according to the scheme of the present application, the area of metal recombination is reduced, and the conversion efficiency of the battery piece can be improved.

[0043] As shown in FIG. 1, Figure 4 In some embodiments, the laser sintering method for the battery piece provided in the present application further includes, before step S20:

[0044] Step S30, adjusting the real-virtual ratio of the laser scanning line segment, the real-virtual ratio being the ratio of the length of the virtual segment to the length of the real segment.

[0045] The length of the virtual segment and the length of the real segment refer to the size of the virtual segment and the real segment in the length direction of the laser scanning line segment, that is, the size in the arrangement direction of the real segments. By adjusting the virtual-real ratio of the laser scanning line segment, the virtual-real ratio of the laser scanning line segment can be adjusted according to the size of different battery pieces or the laser sintering requirements of different battery pieces, so as to ensure the laser sintering effect of the battery piece.

[0046] In some embodiments, the adjustment range of the virtual-real ratio of the laser scanning line segment is 0%-80%. For example, when laser sintering the battery piece, the virtual-real ratio of the laser scanning line segment can be adjusted to 10%, 20%, 30%, 40%, 50%, 60%, 70% or 80%, but is not limited thereto.

[0047] In some embodiments, assuming that the real segment in the laser scanning line segment includes M laser spots, the minimum adjustment amount of the real segment in the laser scanning line segment is 1 / M.

[0048] When the real segment in the laser scanning line segment includes M laser spots, as shown in FIGS. 11A and 11B, it can be seen that by adjusting the number of laser spots in the real segment, the length of the real segment can be adjusted, and then the virtual-real ratio of the laser scanning line segment can be adjusted. It should be noted that when adjusting the virtual-real ratio of the laser scanning line segment, the length of the real segment is adjusted while the length of the virtual segment is kept unchanged or the length of the virtual segment is adjusted at the same time. Figure 5 Figure 6

[0049] When controlling the laser device to scan the battery piece, a plurality of laser scanning line segments are formed, and the plurality of laser scanning line segments are arranged at equal intervals in a direction perpendicular to the laser scanning. The direction of the laser scanning refers to the length direction of the laser scanning line segment.

[0050] In some embodiments, the present application also provides a battery piece processing method, which comprises:

[0051] In step S100, a LECO slurry is used to print a sub-grid on the front surface of the blue film piece of the battery piece, and sintering is performed.

[0052] The specific sintering temperature and sintering time of the battery piece in this step are not limited in the embodiments of the present application, and sintering can be performed according to the specific sintering parameters in the prior art. The LECO (Laser-enhanced contact optimization) slurry is a specific slurry used for laser sintering of the battery piece.

[0053] In step S200, the laser sintering method of the battery piece in any of the above embodiments is used to perform laser sintering on the battery piece.

[0054] ​​The processing method of the battery piece provided in the present application adopts all the technical solutions of all the embodiments of the laser sintering method of the battery piece, and thus has all the beneficial effects brought by the technical solutions of the embodiments of the laser sintering method of the battery piece, which will not be repeated here.

[0055] As shown in Table 1, Table 1 is the change of the electrical performance parameters of the battery piece under different virtual-real ratios. It can be seen that the electrical performance parameters of the battery piece change under different virtual-real ratios, so that the better conversion efficiency of the battery piece can be obtained by adjusting the virtual-real ratio of the laser scanning line segment. Wherein, Eta is the conversion efficiency, Uoc is the open circuit voltage, I sc is the short circuit current, FF is the fill factor, Rser is the series resistance, Rshunt is the parallel resistance, and I Rev2 is the reverse leakage current.

[0056] Table 1

[0057] Fill factor Eta Uoc Isc FF Rser Rshunt IRev2 0％ 25.928 0.7312 13.996 84.80 0.00132 2374 0.029 15％ 25.951 0.7331 13.991 84.86 0.00137 2578 0.027

[0058] In some embodiments, the present application also provides a battery piece obtained by the processing method of the battery piece in the above embodiments. The battery piece obtained by the processing method of the battery piece in the above embodiments only partially forms contact between the grid lines and the silicon piece, thereby reducing the area of metal combination and improving the conversion efficiency of the battery piece.

[0059] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A method of laser sintering of a battery sheet, characterized by, The laser sintering method of the battery piece comprises: placing the battery piece to be sintered in a laser device, and setting a laser scanning line segment of the laser device to comprise a plurality of real segments and a plurality of virtual segments, and the real segments and the virtual segments are arranged alternately, wherein the real segment is a segment with laser scanning, and the virtual segment is a segment without laser scanning; controlling the laser device to scan the battery piece according to the laser scanning line segment.

2. The method of claim 1, wherein the laser sintering is performed by using a laser beam having a wavelength of 1,064 nm. The real segment comprises a plurality of laser spots arranged linearly.

3. The method of claim 1, wherein the laser sintering is performed by using a laser beam having a wavelength of 1,064 nm. The lengths of the plurality of real segments in the laser scanning line segment are the same, and the lengths of the plurality of virtual segments are the same.

4. The method of laser sintering of a battery sheet according to any one of claims 1 to 3, wherein Before controlling the laser device to scan the battery piece according to the laser scanning line segment, the sintering method of the battery piece further comprises: adjusting the real-virtual ratio of the laser scanning line segment, and the real-virtual ratio is the ratio of the length of the virtual segment to the length of the real segment.

5. The method of laser sintering of a battery sheet according to claim 4, wherein, The adjustment range of the real-virtual ratio is 0%-80%.

6. The method of laser sintering of a battery sheet as claimed in claim 4, wherein, The real segment in the laser scanning line segment comprises M laser spots, and the minimum adjustment amount of the real segment is 1 / M.

7. The method of laser sintering of a battery cell as claimed in claim 1, wherein, When controlling the laser device to scan the battery piece, a plurality of laser scanning line segments are formed; The plurality of laser scanning line segments are arranged at equal intervals in the direction perpendicular to the laser scanning.

8. A method of processing a battery sheet, characterized by, The processing method of the battery piece comprises: printing a sub-grid on the front surface of the blue film piece of the battery piece using LECO slurry, and sintering; sintering the battery piece by using the laser sintering method of the battery piece according to any one of claims 1-7.

9. A battery sheet, characterized by The battery piece is obtained by using the processing method of the battery piece according to claim 8.

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