Laser sintering method and processing method of battery piece and battery piece

Abstract

The invention relates to the technical field of battery piece manufacturing, and provides a laser sintering method and a processing method of a battery piece and the battery piece. The laser sintering method of the battery piece comprises the steps that the battery piece to be sintered is placed in laser equipment, a laser scanning line segment of the laser equipment is set to comprise a plurality of real segments and a plurality of virtual segments, the real segments and the virtual segments are arranged alternately, the real segments are segments with laser scanning, and the virtual segments are segments without laser scanning; and controlling the laser equipment to scan the battery piece according to the laser scanning line segment. According to the laser sintering method of the battery piece provided by the invention, the virtual segments and the solid segments are alternately arranged on the laser scanning line segments, and the virtual segments are not scanned by the laser when the battery piece is scanned, which is equivalent to that the grid lines in the battery piece are in contact with the local part of the silicon wafer, so that the metal compounding area 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 and a processing method of a solar cell and a solar cell. Background Art

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

[0003] In the prior art, a bias voltage of about 10V is generally applied to the battery cell during laser sintering, and a high-intensity laser is used to continuously scan the battery cell. Under the action of the local current generated on the grid line of the battery 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, thereby improving the conversion efficiency of the battery cell.

[0004] However, in the prior art, laser sintering causes all the gate lines in the cell to come into contact with the silicon wafer, increasing the composite area of ​​the metal region on the cell, which is likely to affect the improvement of the cell conversion efficiency. Summary of the invention

[0005] The present application provides a laser sintering method, a processing method and a battery cell to solve the technical problem in the prior art that during laser sintering, all grid lines in the battery cell will come into contact with the silicon wafer, increasing the composite area of ​​the metal region on the battery cell, which is likely to affect the improvement of the conversion efficiency of the battery cell.

[0006] In order to solve the above problems, the present application provides a laser sintering method for a battery cell, and the laser sintering method for a battery cell comprises:

[0007] Placing the cell to be sintered on a laser device, and setting the 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 segments are segments with laser scanning, and the virtual segments are segments without laser scanning;

[0008] The laser device is controlled to scan the battery 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 several real segments in the laser scanning line segments are the same, and the lengths of several imaginary segments are the same.

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

[0012] The virtual-to-real ratio of the laser scanning line segment is adjusted, wherein the virtual-to-real ratio is the ratio of the length of the virtual segment to the length of the real segment.

[0013] In some embodiments, the adjustment range of the virtual-to-real ratio is 0%-80%.

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

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

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

[0017] The present application also provides a method for processing a battery cell, the method comprising:

[0018] Print the auxiliary grid on the front of the blue film of the cell using LECO slurry and sinter it;

[0019] The cell is laser sintered using any of the above-mentioned cell laser sintering methods.

[0020] The present application also provides a battery cell, and the battery cell is obtained by using the battery cell processing method.

[0021] The beneficial effect of the embodiment of the present application is: the laser sintering method of the battery cell provided by the present application includes: placing the battery cell to be sintered on the laser equipment, and setting the laser scanning line segment of the laser equipment to include a plurality of real segments and a plurality of virtual segments, and the real segments and the virtual segments are arranged alternately; then controlling the laser equipment to scan the battery cell according to the laser scanning line segment. By setting the scanning line segment to a scanning line segment in which the real segments and the virtual segments are arranged alternately, since the real segments in the scanning line segment are the segments with laser scanning and the virtual segments are the segments without laser scanning, in this way, after the battery cell is laser scanned, the gate line and the silicon wafer in the battery cell only form a partial contact, thereby reducing the area of ​​metal compounding and improving the conversion efficiency of the battery cell.

[0022] Before controlling the laser equipment to scan the battery cell according to the laser scanning line segment, the length of the real segment can be adjusted by adjusting the number of laser spots in the real segment of the laser scanning line segment, and then the virtual-to-real ratio of the laser scanning line segment can be adjusted to find a suitable virtual-to-real ratio according to the production line conditions to maximize the conversion efficiency of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0024] Figure 1 is a flow chart of a laser sintering method for a cell provided in one embodiment of the present application;

[0025] Figure 2 It is a schematic diagram of the structure of several laser scanning line segments in the laser sintering method of a battery cell provided in one embodiment of the present application;

[0026] Figure 3 It is a schematic diagram of the structure of the laser scanning line segment in the laser sintering method of the battery cell provided in one embodiment of the present application;

[0027] Figure 4 is a flow chart of a laser sintering method for a cell provided in another embodiment of the present application;

[0028] Figure 5 It is an image of a laser scanning line segment irradiated on a cell in a laser sintering method of a cell provided in an embodiment of the present application;

[0029] Figure 6 It is an image of a laser scanning line segment irradiated on a battery cell in a laser sintering method of a battery cell provided in another embodiment of the present application. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It will be appreciated that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some but not all structures related to the present application are shown in the drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the art without making creative work are within the scope of protection of the present application.

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] See also Figure 1 The present application provides a method for laser sintering of a cell, which can be used in the processing of TOPcon cells. In the processing of the cell, after printing the secondary grid with LECO slurry on the front of the blue film of the cell and sintering it, the laser sintering method for the cell provided in the present application can be used to laser sinter the cell.

[0033] The laser sintering method of the cell provided in the embodiment of the present application may include the following steps:

[0034] Step S10, placing the battery cell to be sintered on a laser device, and setting the 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 segments are segments with laser scanning, and the virtual segments are segments without laser scanning.

[0035] In this step, the cell to be sintered is placed in the laser equipment, wherein the cell to be sintered refers to the cell to be further laser sintered after the auxiliary grid is printed on the front side of the blue film of the cell using LECO slurry and sintered.

[0036] Laser sintering of the cell can be completed by controlling the laser device to emit a laser scanning line segment to laser scan the cell. It can be understood that the laser device includes a laser scanning structure, and the laser scanning structure includes a plurality of scanning units, and the scanning units are used to emit laser scanning line segments. The plurality of scanning units are arranged at equal intervals along the length direction perpendicular to the laser scanning line segment, such as Figure 2 As shown, correspondingly, when controlling the laser device to scan the battery cell, a plurality of laser scanning line segments can be controlled to scan the battery cell, and the plurality of laser scanning line segments are arranged at equal intervals in a direction perpendicular to the length of the laser scanning line segments.

[0037] Since the real segment in the laser scanning line segment is the segment with laser scanning, the virtual segment is the 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 two adjacent real segments, such as Figure 3 For example, in some embodiments, the real segment in the laser scanning line segment may include a plurality of laser spots arranged linearly, that is, a plurality of laser spots are arranged in a line segment to form a real segment, such as Figure 5 and Figure 6 It should be noted that, among the laser spots linearly arranged in the real segment, two adjacent laser spots may be tangent or intersected, 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 area of ​​intersection between two adjacent laser spots.

[0038] By controlling the position of the laser spot in the laser scanning line segment, the laser scanning line segment of the laser device can be set to include several real segments and several imaginary segments, and the real segments and the imaginary segments are arranged alternately. For example, the laser spots arranged linearly in the scanning unit are arranged at intervals, and the interval segments are imaginary segments.

[0039] Of course, in some embodiments, the lengths of several real segments in the laser scanning line segment are the same, and the lengths of several imaginary segments are the same, which facilitates the setting of the laser scanning line segment and ensures the uniformity of the sintering of the battery cell by each laser scanning line segment.

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

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

[0042] The laser sintering method of the battery cell provided in the above embodiment of the present application sets the laser scanning line segment for scanning the battery cell to a scanning line segment in which real segments and imaginary segments are alternately arranged. In this way, after the battery cell is laser scanned, the gate line and the silicon wafer in the battery cell are only partially in contact, thereby reducing the area of ​​metal compounding and improving the conversion efficiency of the battery cell. It should be noted that the area of ​​metal compounding refers to the area where the slurry forms ohmic contact with the silicon wafer. This area destroys the passivation layer and increases the compounding, and it is not the area with metal that will produce compounding. During laser sintering, since the place where the laser is scanned will form carriers passing through, local sintering (temperature rise), the glass will destroy the passivation layer during the sintering process, forming ohmic contact, increasing compounding, and the unscanned area will basically not be destroyed. Therefore, after the battery cell is laser scanned by the present application solution, the area of ​​metal compounding is reduced, which can improve the conversion efficiency of the battery cell.

[0043] like Figure 4 As shown, in some embodiments, the laser sintering method of the battery cell provided in the present application, before step S20, further includes:

[0044] Step S30, adjusting the virtual-to-real ratio of the laser scanning line segment, where the virtual-to-real ratio is 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 along the length direction of the laser scanning line segment, that is, the size in the arrangement direction of several real segments. By making the virtual-to-real ratio of the laser scanning line segment adjustable, the virtual-to-real ratio of the laser scanning line segment can be adjusted according to the size of different battery cells or the laser sintering requirements of different battery cells, thereby ensuring the laser sintering effect of the battery cells.

[0046] In some embodiments, the virtual-to-real ratio of the laser scanning line segment is adjusted in a range of 0%-80%. For example, when laser sintering a cell, the virtual-to-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, it is assumed that the real segment in the laser scanning line segment includes M laser spots, and correspondingly, 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, such as Figure 5 and Figure 6 As shown, 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 segment can be adjusted. It should be noted that when adjusting the virtual-real ratio of the laser scanning segment, the length of the virtual segment can be kept unchanged or adjusted at the same time while adjusting the length of the real segment.

[0049] When the laser device is controlled to scan the cell, 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 direction, wherein the laser scanning direction refers to the length direction of the laser scanning line segment.

[0050] In some embodiments, the present application further provides a method for processing a battery cell, the method for processing a battery cell comprising:

[0051] Step S100, using LECO slurry to print a secondary grid on the front side of the blue film of the cell, and sintering.

[0052] In the embodiment of the present application, there is no restriction on the specific sintering temperature and sintering time of the cell in this step, and the sintering can be performed according to the specific sintering parameters in the prior art. LECO (Laser-enhanced contact optimization) slurry is a specific slurry used when laser sintering the cell.

[0053] Step S200: laser sintering the cell using any of the cell laser sintering methods in the above embodiments.

[0054] The processing method of the battery cell provided in the present application adopts all the technical solutions of all the embodiments of the laser sintering method of the above-mentioned battery cell, and therefore at least has all the beneficial effects brought by the technical solutions of the embodiments of the laser sintering of the above-mentioned battery cell, which will not be described one by one here.

[0055] As shown in Table 1 below, Table 1 shows the changes in the electrical performance parameters of the battery under different virtual-real ratios. It can be seen that the electrical performance parameters of the battery change under different virtual-real ratios, so that the better conversion efficiency of the battery can be obtained by adjusting the virtual-real ratio of the laser scanning line segment. Among them, Eta is the conversion efficiency, Uoc is the open circuit voltage, Isc is the short circuit current, FF is the fill factor, Rser is the series resistance, Rshunt is the parallel resistance, and Irev2 is the reverse leakage current.

[0056] Table 1

[0057] Virtual-Real Ratio Eta Uoc Isc FF R 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 further provides a cell, which is obtained by the cell processing method in the above implementation. In the cell obtained by the cell processing method in the above embodiment, the gate line and the silicon wafer are only partially in contact, thereby reducing the area of ​​metal composite and improving the conversion efficiency of the cell.

[0059] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A laser sintering method for a battery cell, characterized in that: The laser sintering method of the battery cell comprises: Placing the cell to be sintered on a laser device, and setting the 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 segments are segments with laser scanning, and the virtual segments are segments without laser scanning; The laser device is controlled to scan the battery cell according to the laser scanning line segment.

2. The laser sintering method of a battery cell according to claim 1, characterized in that: The real segment includes a plurality of laser spots arranged linearly.

3. The laser sintering method of a battery cell according to claim 1, characterized in that: The lengths of several real segments in the laser scanning line segments are the same, and the lengths of several imaginary segments are the same.

4. The laser sintering method of a cell according to any one of claims 1 to 3, characterized in that: Before controlling the laser device to scan the battery cell according to the laser scanning line segment, the battery cell sintering method further includes: The virtual-to-real ratio of the laser scanning line segment is adjusted, wherein the virtual-to-real ratio is the ratio of the length of the virtual segment to the length of the real segment.

5. The laser sintering method of a battery cell according to claim 4, characterized in that: The adjustment range of the virtual-real ratio is: 0%-80%.

6. The laser sintering method of a battery cell according to claim 4, characterized in that: The real segment in the laser scanning line segment includes M laser spots, and the minimum adjustment amount of the real segment is 1 / M.

7. The laser sintering method of a battery cell according to claim 1, characterized in that: When controlling the laser device to scan the battery sheet, a plurality of laser scanning line segments are formed; The plurality of laser scanning line segments are arranged at equal intervals in a direction perpendicular to the laser scanning direction.

8. A method for processing a battery cell, characterized in that: The processing method of the battery cell includes: Print the auxiliary grid on the front of the blue film of the cell using LECO slurry and sinter it; The cell is laser sintered using the cell laser sintering method according to any one of claims 1 to 7.

9. A battery cell, characterized in that: The battery cell is obtained by the battery cell processing method according to claim 8.

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