Manufacturing method of solar cell

Abstract

The invention relates to the technical field of solar cells, in particular to a manufacturing method of a solar cell. In the embodiment of the invention, the target irradiation process is configured in the laser-assisted sintering treatment process, so that the moving direction of the laser on the solar cell substrate and the lengthwise extension direction of the first electrode in the target irradiation process intersect with each other, and a larger range covering a non-electrode area can be formed; therefore, more carriers can be excited, the contact performance of the formed first electrode and the substrate is improved more remarkably, the precision requirement for controlling laser can be lowered, the process window is expanded, and the manufacturing efficiency is improved. Therefore, by configuring the target irradiation process, the contact performance of the first electrode and the substrate can be improved to a greater extent, the conversion efficiency of the solar cell is improved, processing and manufacturing are facilitated, and the manufacturing efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a method for manufacturing solar cells. Background Art

[0002] Solar cells are devices that convert sunlight into electrical energy. Solar cells use the photovoltaic principle to generate carriers, and then use electrodes to extract the carriers, which is conducive to the effective use of electrical energy. However, the conversion efficiency of current solar cells needs to be further improved. Summary of the invention

[0003] Based on this, it is necessary to provide a method for manufacturing a solar cell, which is at least beneficial to improving the conversion efficiency of the solar cell.

[0004] The present application provides a method for manufacturing a solar cell, comprising:

[0005] providing a solar cell substrate;

[0006] Forming a first initial electrode on a solar cell substrate by a metallization heat treatment process;

[0007] Controlling the laser to move and irradiate on the solar cell substrate to perform laser-assisted sintering on the first initial electrode to form the first electrode, thereby obtaining the solar cell;

[0008] The laser is controlled to continuously move and irradiate the solar cell substrate at least once;

[0009] There is a target irradiation process in all continuous moving irradiation processes. During the target irradiation process, the moving direction of the laser on the solar cell substrate and the longitudinal extension direction of the first electrode intersect each other, and the moving direction of the laser on the solar cell substrate and the longitudinal extension direction of the first electrode are both perpendicular to the thickness direction of the solar cell substrate.

[0010] In one embodiment, the laser is controlled to continuously move and irradiate on the solar cell substrate a plurality of times;

[0011] The moving direction of the laser in the first continuous moving irradiation process is parallel to the longitudinal extension direction of the first electrode; or

[0012] The first continuous moving irradiation process is the target irradiation process.

[0013] In one of the embodiments, the number of executions of controlling the laser to perform continuous moving irradiation on the solar cell substrate is at least three times; in all continuous moving irradiation processes, except for the first continuous moving irradiation process, the continuous moving irradiation processes are target irradiation processes; the moving directions of the laser on the solar cell substrate in all target irradiation processes constitute a moving direction set;

[0014] The moving direction set includes multiple moving directions with the same direction or multiple moving directions with opposite directions; or

[0015] In the moving direction set, there are multiple moving directions that intersect with each other.

[0016] In one embodiment, the reverse bias voltage of the laser in the first continuous moving irradiation process is greater than any continuous moving irradiation process in all continuous moving irradiation processes except the first continuous moving irradiation process; and / or

[0017] The power of the laser in the first continuous moving irradiation process is greater than that in any continuous moving irradiation process except the first continuous moving irradiation process; and / or

[0018] In all the continuous moving irradiation processes except the first continuous moving irradiation process, the laser used is configured as a red light laser.

[0019] In one embodiment, the irradiation area formed by each continuous moving irradiation process is the same area.

[0020] In one embodiment, different irradiation areas exist in the irradiation areas formed by all the continuous moving irradiation processes.

[0021] In one of the embodiments, a first target area exists in all irradiated areas;

[0022] The first target area is determined based on the location of the first initial electrode.

[0023] In one of the embodiments, a second target area exists in all irradiated areas;

[0024] The second target area is determined based on a corresponding area of ​​a side surface of the solar cell substrate where the first initial electrode is located; the corresponding area includes at least one of a poorly sintered area of ​​the first initial electrode and an edge area of ​​the solar cell substrate.

[0025] In one embodiment, the order of all irradiation areas formed by the execution order of all the continuous moving irradiation processes is a preset order;

[0026] The sorting sequence number corresponding to the second target area is an intermediate sequence number; or

[0027] The sorting number corresponding to the second target area is the first number; or

[0028] The sorting sequence number corresponding to the second target area is the last sequence number.

[0029] In one embodiment, the angle between the moving direction of the laser during the target irradiation process and the longitudinal extension direction of the first electrode is 45° to 135°; and / or

[0030] The reverse bias voltage of the laser is 10V to 30V, the power of the laser is 10W to 100W, and the scanning speed of the laser is 20000mm / s to 200000mm / s; and / or

[0031] The same irradiation area formed by the same continuous moving irradiation process is extended continuously or discontinuously; and / or

[0032] The laser is controlled to perform continuous moving irradiation on the solar cell substrate twice.

[0033] In one embodiment, controlling the laser to move and irradiate on the solar cell substrate to perform laser-assisted sintering on the first initial electrode to form the first electrode, thereby obtaining the solar cell, comprises:

[0034] A laser is provided; the laser is located on one side of the thickness direction of the solar cell substrate and is arranged opposite to the central area of ​​the solar cell substrate;

[0035] The laser is controlled to rotate so that the moving irradiation area of ​​the laser emitted by the laser can cover at least a portion of the solar cell substrate, so as to perform laser-assisted sintering on the first preliminary electrode to form the first electrode.

[0036] In the manufacturing method of the solar cell, after forming the first initial electrode in the metallization heat treatment process, the first initial electrode is subjected to laser-assisted sintering to form the first electrode, thereby obtaining the solar cell. In this process, by configuring the target irradiation process in the laser-assisted sintering process, the moving direction of the laser on the solar cell substrate in the target irradiation process and the longitudinal extension direction of the first electrode intersect each other, so that, on the one hand, a part of the irradiation area formed by the laser in the target irradiation process covers the electrode area of ​​the solar cell, which can improve the contact performance between the first electrode and the substrate; on the other hand, another part of the irradiation area formed by the laser in the target irradiation process covers the non-electrode area of ​​the solar cell, and the non-electrode area can be used to excite the carriers. When a certain reverse bias is applied, these excited charge carriers will move in a directional manner to generate local current. This local current can further increase the temperature of the sintering area, promote the further mutual fusion and expansion of the first initial electrode and the substrate, thereby further improving the contact performance between the formed first electrode and the substrate. Compared to the method in which the moving direction of the laser is parallel to the longitudinal extension direction of the first electrode, and the laser acts on the first initial electrode or the area near the first initial electrode, the aforementioned laser can not only form a larger coverage of the non-electrode area during the target irradiation process, and then can excite more carriers, so that the contact performance between the formed first electrode and the substrate is more significantly improved, but also the accuracy requirements for controlling the laser can be reduced, the process window can be expanded, and the manufacturing efficiency can be improved. Therefore, by configuring the aforementioned target irradiation process, not only can the contact performance between the first electrode and the substrate be improved to a greater extent, the conversion efficiency of the solar cell can be improved, but also processing and manufacturing can be facilitated and manufacturing efficiency can be improved.

[0037] Additional aspects and advantages of the embodiments of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the embodiments below. The accompanying drawings are only for the purpose of illustrating the embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0039] Figure 1 A schematic diagram of a process for manufacturing a solar cell provided in some embodiments of the present application;

[0040] Figure 2 A schematic cross-sectional view of a solar cell substrate provided in some embodiments of the present application;

[0041] Figure 3for Figure 2 A schematic diagram of the structure of a solar cell substrate with metal paste printed on it;

[0042] Figure 4 for Figure 2 A schematic diagram of the structure of a solar cell substrate having a first initial electrode formed thereon;

[0043] Figure 5 for Figure 2 A schematic diagram of a structure in which a first electrode is formed on a solar cell substrate;

[0044] Figure 6 Schematic diagram of laser irradiation on a solar cell substrate in some embodiments of the present application;

[0045] Figure 7 A schematic diagram of a mobile illumination path provided for some embodiments of the present application;

[0046] Figure 8 Schematic diagram of laser irradiation on a solar cell substrate in some other embodiments of the present application;

[0047] Fig. 9 A schematic diagram of an irradiation area in some embodiments of the present application;

[0048] Fig.10 Schematic diagram of the irradiation area in some other embodiments of the present application;

[0049] Fig.11 A schematic diagram of an irradiation area on a solar cell substrate provided in some embodiments of the present application;

[0050] Fig.12 Schematic diagram of a mobile irradiation path provided for other embodiments of the present application;

[0051] Fig.13 Schematic diagram of a mobile irradiation path provided for other embodiments of the present application;

[0052] Fig.14 A schematic diagram of a mobile irradiation path provided in some further embodiments of the present application;

[0053] Fig.15 A schematic diagram of a first target area on a solar cell substrate provided in some embodiments of the present application;

[0054] Fig.16 A schematic diagram of a second target area on a solar cell substrate provided in some embodiments of the present application;

[0055] Fig.17 A schematic diagram of a mobile illumination path provided for some embodiments of the present application;

[0056] Fig.18 A schematic flow chart of step S130 in the method for manufacturing a solar cell provided in some embodiments of the present application;

[0057] Fig.19 A schematic diagram of the cross-sectional structure of a solar cell provided in some embodiments of the present application.

[0058] Description of reference numerals:

[0059] Solar cell 100;

[0060] Solar cell substrate 110, substrate 111, first surface m1, second surface m2, doping layer 112, first passivation layer 113, tunneling layer 114, doped conductive layer 115, second passivation layer 116, first electrode E1, second electrode E2;

[0061] Metal paste e0, first initial electrode e1;

[0062] Laser Q, laser L, moving irradiation path P, irradiation area W, first target area Z1, second target area Z2;

[0063] Moving direction M, first angle ɵ, first direction F 1 , the second direction F 2 , the third party to F 3 ;

[0064] Steps S110, S120, S130, S131, S132. DETAILED DESCRIPTION

[0065] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0066] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0067] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0068] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly limited. It is worth noting that in the following description and the attached claims, "electrical connection" between one feature and another feature not only includes one feature directly contacting another feature to form an electric energy transmission or current transmission channel, but also includes an intermediate feature between one feature and another feature, and the one feature, the other feature and the intermediate feature between them form an electric energy transmission channel or a current transmission channel to achieve electric energy transmission or transmission. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0069] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0070] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0071] Figure 1 A schematic flow chart of a method for manufacturing a solar cell provided in some embodiments of the present application is shown; for ease of explanation, only contents related to the embodiments of the present application are shown.

[0072] Please refer to Figure 1 The present invention provides a method for manufacturing a solar cell, comprising the following steps:

[0073] Step S110, providing a solar cell substrate;

[0074] Step S120, forming a first initial electrode on the solar cell substrate by a metallization heat treatment process;

[0075] Step S130, controlling the laser to perform moving irradiation on the solar cell substrate to perform laser-assisted sintering on the first initial electrode to form a first electrode, thereby obtaining a solar cell; wherein, the number of executions of controlling the laser to perform continuous moving irradiation on the solar cell substrate is at least once; there is a target irradiation process in all continuous moving irradiation processes, and in the target irradiation process, the moving direction of the laser on the solar cell substrate and the longitudinal extension direction of the first electrode intersect with each other, and the moving direction of the laser on the solar cell substrate and the longitudinal extension direction of the first electrode are both perpendicular to the thickness direction of the solar cell substrate.

[0076] In step S110, in combination with reference Figure 2 , Figure 21 shows a schematic cross-sectional structure diagram of a solar cell substrate 110 provided in some embodiments of the present application. The solar cell substrate 110 includes a substrate 111 and a layer structure arranged on the substrate 111. Figure 2 For example, in the embodiment of the present application, the first direction F 1 is the thickness direction of the substrate 111, and the second direction F 2 and third parties to F 3 The first direction F may be the length direction and the width direction of the substrate 111, respectively. 1 , the second direction F 2 and third parties to F 3 It should be noted that the dimension of the base 111 along the length direction may be greater than or equal to the dimension along the width direction, and no specific limitation is made here.

[0077] Specifically, the substrate 111 has a doping element in it, and the doping element type is N-type or P-type. The substrate 111 has a first surface m1 and a second surface m2 that are oppositely disposed. The first surface m1 and the second surface m2 are disposed along a first direction F 1 Relative arrangement. The first surface m1 and the second surface m2 can both be used to receive incident light. In the embodiment of the present application, the first surface m1 of the substrate 111 is the light-receiving surface, and the second surface m2 of the substrate 111 is the backlight surface. It can be understood that the light-receiving surface and the backlight surface are relative, and the light-receiving surface is specifically the surface on which sunlight mainly irradiates in the solar cell or on the substrate 111 in the photovoltaic module. With the development of solar cell technology, the backlight surface will also receive energy from sunlight, mainly from reflected light or scattered light in the surrounding environment.

[0078] The first surface m1 side of the substrate 111 may be provided with a doping layer 112 and a first passivation layer 113 in sequence, and the second surface m2 side of the substrate 111 may be provided with a tunneling layer 114, a doped conductive layer 115 and a second passivation layer 116 in sequence, so that a solar cell substrate 110 is formed. The solar cell substrate 110 may constitute at least a portion of a TOPCon (Tunnel Oxide Passivating Contacts) cell. The layer structure provided on the substrate 111 may be improved according to actual use requirements. Of course, in other embodiments, the first surface m1 and the second surface m2 of the substrate 111 may be provided with different layers or structures according to specific use requirements. For example, the solar cell substrate 110 may also be used to constitute at least a portion of a BC (Back Contact) cell. That is, the required solar cell substrate 110 may be manufactured according to actual use requirements, and may be used to constitute different types of solar cells, without specific limitation herein.

[0079] In step S120, the metallization heat treatment process may be a printing process and a sintering process. The printing process refers to a process of printing the metal slurry on the corresponding area on the solar cell substrate. The printing process includes at least one of a screen printing process, a gravure printing process, a relief printing process, a flexographic printing process, a laser transfer process, an inkjet printing process, and a 3D printing process. The sintering process refers to a heat treatment process that allows at least part of the metal slurry to penetrate the corresponding layer structure on the solar cell substrate.

[0080] Specifically, Figure 3 For example, Figure 3 Shows Figure 2 The schematic diagram of the structure of the solar cell substrate 110 is printed with metal paste e0, and the metal paste e0 is printed on the surface of the first passivation layer 113 away from the doping layer 112. The area where the metal paste e0 is printed can be determined according to actual use requirements and is not specifically limited here. Figure 4 , Figure 4 Shows Figure 2 The schematic diagram of the structure of a solar cell substrate 110 is shown, and the metal paste e0 mentioned above is sintered, and at least part of the metal paste e0 is burned through the first passivation layer 113 of a certain thickness to form the first initial electrode e1. At this time, at least part of the first initial electrode e1 has not yet formed contact with the doping layer 112. Of course, at least part of the metal paste e0 can also penetrate the first passivation layer 113 and electrically contact the doping layer 112 to form the first initial electrode e1. At this time, at least part of the first initial electrode e1 is in contact with the doping layer 112. In this process, the metal paste e0 can be sintered in a sintering furnace.

[0081] In step S130, laser irradiation forms a light spot on the solar cell substrate. The shape of the light spot includes but is not limited to a rectangular, circular or elliptical shape. During the movement of the laser, at least most of the area where the first initial electrode is located is covered by the area irradiated by the formed light spot. In this way, after the laser is moved and irradiated, the first initial electrode can be subjected to laser-assisted sintering to form the first electrode. Figure 5 , Figure 5 Shows Figure 2The schematic diagram of the structure of the solar cell substrate 110 is shown. The first initial electrode E1 is formed into the first electrode E1 through laser-assisted sintering. The first electrode E1 forms an ohmic contact with the doping layer 112. In this process, the laser can destroy the portion of the first passivation layer 113 located in the electrode region, so that the first initial electrode e1 is partially melted and diffused, and can further directly form contact with the doping layer 112 to form a tiny alloy junction, thereby reducing the contact resistance and improving the transmission efficiency of electrons. Among them, the electrode region is a region for setting the first electrode E1, and the electrode region is opposite to the non-electrode region, which is a region where the first electrode E1 is not set.

[0082] The laser can be emitted by a laser, and the laser can be configured as a line laser. During the movement of the laser, the irradiation area formed by the linear beam can be roughly regarded as a line. Figure 6 , Figure 6 Schematic diagram showing the laser L irradiating onto the solar cell substrate 110 in some embodiments of the present application, Figure 6 The corresponding electrodes are not shown in the figure. The laser L emitted by the laser Q can be roughly regarded as a continuous linear beam. Figure 7 , Figure 7 Schematic diagram showing a moving irradiation path P provided in some embodiments of the present application, Figure 7 The arrow in the figure indicates the moving irradiation path P of the laser L, and the laser Q can be controlled to move along the moving irradiation path P. The number of emitted lasers L can be determined according to specific usage requirements, that is, the formed Figure 7 The number of moving irradiation paths P in the embodiment is not specifically limited. Accordingly, multiple lasers Q arranged side by side can be configured to emit multiple lasers L arranged side by side. Of course, one laser Q can also emit multiple lasers L, which is not specifically limited here. It can be understood that the denser the moving irradiation paths P formed, the more areas on the solar substrate 111 are irradiated.

[0083] Of course, in some other embodiments, in combination with reference Figure 8 , Figure 8 The schematic diagram of laser L irradiating on the solar cell substrate 110 in some other embodiments of the present application is shown. The emitted laser L generally forms a linear light spot with a certain length (which can be regarded as a long strip of light spot) on the solar cell substrate 110. The irradiated area formed by moving along the extension direction of the light spot can also be regarded as a line. The required laser can be selected according to specific usage requirements, and no specific limitation is made here.

[0084] The laser performs continuous moving irradiation, that is, the laser moves along one direction to irradiate the solar cell substrate, and the moving process of the laser irradiating on the solar cell substrate can be regarded as continuous. One continuous moving irradiation process is that the laser moves along one direction to irradiate the solar cell substrate once. Since the laser is emitted through a laser, the continuous moving irradiation process can be regarded as controlling the laser to move along one direction to irradiate the solar cell substrate. In this process, the laser can emit light continuously or intermittently. In the case of continuous laser light emission, Fig. 9 For example, the irradiation area W formed by the laser in the process of continuous moving irradiation is continuous. Fig.10 For example, the irradiation area W formed by the laser in the continuous moving irradiation process is discontinuous, and the discontinuous irradiation area W can be regarded as an intermittent irradiation area W. The continuous moving irradiation process of the laser can be set according to actual use requirements, and no specific limitation is made here.

[0085] The irradiation area formed during the continuous moving irradiation process has a starting end and an ending end. The starting end and the ending end of the irradiation area can be set according to the use requirements, and the required irradiation area can be obtained by controlling the light emission process and the moving process of the laser. Fig.11 , Fig.11 A schematic diagram of an irradiation area W on a solar cell substrate 100 provided in some embodiments of the present application is shown. To facilitate the illustration of the irradiation area W, the related electrodes are not shown. The starting end of the irradiation area W is one side edge of the solar cell substrate 110, and the ending end of the irradiation area W is the other side edge of the solar cell substrate 110. Fig.11 In the illustrated case, the irradiation area W is a continuous irradiation area. It can be understood that the width of each irradiation area W can be controlled by controlling the width of the light spot, and the spacing between two adjacent irradiation areas W can be controlled by controlling the distance between the corresponding two lasers (that is, the spacing between the two adjacent light spots). Of course, in some other embodiments, the starting end and / or the ending end of the irradiation area W may not be the corresponding edge on the solar cell substrate 110, and can be set according to the specific use situation, and no specific limitation is made here.

[0086] The continuous moving irradiation is performed at least once, that is, the number of continuous moving irradiation processes can be one, two or other numbers. There is a target irradiation process in all continuous moving irradiation processes, that is, when the continuous moving irradiation process is performed once, the continuous moving irradiation process is the target irradiation process, and when the continuous moving irradiation process is performed multiple times, at least one continuous moving irradiation process is the target irradiation process. For the target irradiation process, Figure 7 For example, the longitudinal extension direction of the first electrode E1 is the third direction F shown in the figure.3 The thickness direction of the solar cell substrate 110 is the first direction F shown in the figure. 1 , the moving direction M of the laser on the solar cell substrate 110 and the third direction F 3 intersect each other, that is, the moving direction M and the third direction F 3 It is set at a first angle ɵ. Figure 7 The moving direction M and the third direction F are shown in FIG. 3 Perpendicular to each other, the moving direction M and the second direction F 2 In the case of being parallel to each other, that is, the first angle ɵ is 90°. Of course, the first angle ɵ may also be other angles, which are not specifically limited here.

[0087] Therefore, in the above-illustrated situation, after forming the first initial electrode in the metallization heat treatment process, the first initial electrode is subjected to laser-assisted sintering to form the first electrode, thereby obtaining a solar cell. In this process, by configuring the target irradiation process in the laser-assisted sintering process, the moving direction of the laser on the solar cell substrate in the target irradiation process and the longitudinal extension direction of the first electrode intersect each other, so that, on the one hand, a part of the irradiation area formed by the laser in the target irradiation process covers the electrode area of ​​the solar cell, which can improve the contact performance between the first electrode and the substrate; on the other hand, another part of the irradiation area formed by the laser in the target irradiation process covers the non-electrode area of ​​the solar cell, and the non-electrode area can be used to excite the carriers. When a certain reverse bias is applied, these excited charge carriers will move in a directional manner to generate local current. This local current can further increase the temperature of the sintering area, promote the further mutual fusion and expansion of the first initial electrode and the substrate, thereby further improving the contact performance between the formed first electrode and the substrate.

[0088] In the relevant implementation, the laser moving direction is usually parallel to the longitudinal extension direction of the first electrode, and the laser acts on the first initial electrode or the area near the first initial electrode to perform laser assisted sintering. However, this method can only perform laser assisted sintering on the electrode area, which limits the room for improving contact performance. At the same time, since it is necessary to align the first initial electrode or the area near the first initial electrode, it is necessary to control the alignment accuracy of the laser, which makes the laser assisted sintering process difficult to control and the process efficiency is too low.

[0089] It can be understood that compared with the related implementation methods mentioned above, the laser mentioned above can not only form a larger coverage range of the non-electrode area during the target irradiation process, thereby exciting more carriers, thereby significantly improving the contact performance between the formed first electrode and the substrate, but also reduce the accuracy requirements for controlling the laser, expand the process window and improve production efficiency.

[0090] Therefore, by configuring the aforementioned target irradiation process, not only can the contact performance between the first electrode and the substrate be improved to a greater extent, and the conversion efficiency of the solar cell be improved, but also the processing and manufacturing can be facilitated and the manufacturing efficiency can be improved.

[0091] In some embodiments, the laser is controlled to perform continuous moving irradiation on the solar cell substrate multiple times, wherein the moving direction of the laser in the first continuous moving irradiation process is parallel to the longitudinal extension direction of the first electrode; or, the first continuous moving irradiation process is a target irradiation process.

[0092] For the case where the first continuous moving irradiation process is not the target irradiation process, Fig.12 As an example, the moving direction M of the laser is parallel to the longitudinal extension direction of the first electrode E1, that is, the moving direction M is parallel to the third direction F 3 Parallel to each other. Fig.12 The extension direction of the moving irradiation path P shown in FIG. Figure 7 The extending directions of the moving irradiation paths P shown in the figure are perpendicular to each other. At this time, the laser can be moved to irradiate the first initial electrode region on the solar cell substrate 110, and the first initial electrode region includes the region where the first initial electrode is located or the region near the first initial electrode. In this way, the first initial electrode can be preliminarily laser-assisted sintering treated (which can be regarded as pre-assisted sintering treatment) by using the first continuous moving irradiation process, and then the first initial electrode can be further laser-assisted sintering treated again by using the subsequent target irradiation process.

[0093] Of course, in some other embodiments, the first continuous moving irradiation process may also be a laser moving irradiation on a non-first initial electrode region on the solar cell substrate to induce the generation of carriers and preliminarily promote further mutual fusion and co-diffusion of the first initial electrode and the substrate.

[0094] In the case where the first continuous moving irradiation process is a target irradiation process, the target irradiation process can be used to first perform auxiliary sintering treatment on the first initial electrode and the non-first initial electrode area, and at the same time, the first initial electrode and the non-first initial electrode area are preliminarily treated, and then the subsequent continuous moving irradiation process is controlled to complete the required laser-assisted sintering process.

[0095] In the first continuous moving irradiation process exemplified above, different contact forms between the first initial electrode and the substrate can be obtained by combining different preliminary processing processes. According to different contact forms, different subsequent continuous moving irradiation processes can be configured in a targeted manner, thereby achieving different process processes and different contact performances to meet different usage requirements.

[0096] For example, when the continuous moving irradiation is performed twice, the first continuous moving irradiation process may be as follows: Fig.12 In the illustrated situation, the last continuous moving irradiation process is a target irradiation process, the reverse bias voltage of the laser used in the last continuous moving irradiation process is less than the reverse bias voltage of the laser used in the first continuous moving irradiation process, and the power of the laser used in the last continuous moving irradiation process is less than the power of the laser used in the first continuous moving irradiation process. The first continuous moving irradiation process can make the first initial electrode form a preliminary contact with the aforementioned doping layer without metal recombination, and the last continuous moving irradiation process can make the first initial electrode form an ohmic contact with the doping layer, and the carriers generated in the non-electrode region help the first initial electrode and the doping layer to further fuse and diffuse, thereby improving the contact performance.

[0097] In this way, the subsequent continuous moving irradiation processes can be flexibly configured according to the specific process of the first continuous moving irradiation process. By controlling the relevant parameters of the laser in different continuous moving irradiation processes, the process control window is expanded, and the controllability is higher. Not only can the required solar cells be obtained according to usage requirements, but it is also further facilitated to manufacture.

[0098] In some embodiments, the laser is controlled to perform continuous moving irradiation on the solar cell substrate at least three times. In all continuous moving irradiation processes, all continuous moving irradiation processes except the first continuous moving irradiation process are target irradiation processes. The moving direction of the laser on the solar cell substrate in all target irradiation processes constitutes a moving direction set. In the moving direction set, there are multiple moving directions with the same direction or multiple moving directions with opposite directions; or, in the moving direction set, there are multiple moving directions that intersect with each other.

[0099] The moving direction set refers to the target irradiation process, and the moving direction set refers to a set consisting of multiple moving directions. Each target irradiation process corresponds to a moving direction, and the number of target irradiation processes is the same as the number of moving directions in the moving direction set.

[0100] Take the example of a moving direction set in which there are multiple moving directions with the same direction, that is, there are multiple target irradiation processes with the same moving direction of the laser, and the moving direction of the laser is the same during these multiple target irradiation processes. Take the example of a moving direction set in which there may be multiple moving directions with opposite directions, that is, there are multiple target irradiation processes with opposite moving directions of the laser, and the moving directions of the laser are opposite during these multiple target irradiation processes. When these multiple target irradiation processes are adjacent target irradiation processes, the laser can be roughly regarded as reciprocating in the corresponding directions. Of course, the moving direction set can also simultaneously contain multiple moving directions with the same direction and multiple moving directions with opposite directions. For example, in combination with reference Fig.13, Fig.13 Schematic diagrams showing moving irradiation paths P provided in some other embodiments of the present application are shown. Figure 7 The moving directions M and Fig.13 The moving direction M shown in FIG. is opposite to that shown in FIG. Fig.14 , Fig.14 Schematic diagram of a moving irradiation path P provided in some further embodiments of the present application is shown. Figure 7 The moving directions M and Fig.14 The movement directions M indicated in the figure intersect each other.

[0101] In this way, when there are multiple moving directions with the same direction or multiple moving directions with opposite directions, it is helpful to control the moving process of the laser. Furthermore, when the moving directions corresponding to two adjacent target irradiation processes are opposite, the sintering efficiency can be further improved. When there are multiple moving directions with intersecting directions, it is helpful to irradiate the solar cell substrate more comprehensively and further improve the contact performance.

[0102] In some embodiments, the reverse bias voltage of the laser in the first continuous motion irradiation process is greater than that in any continuous motion irradiation process except the first continuous motion irradiation process.

[0103] Since a larger reverse bias can enhance the carrier transmission capability, it is helpful for the mutual diffusion between the first initial electrode and the doping layer to form a good ohmic contact. Therefore, the electric field strength can be enhanced through the first continuous moving irradiation process, which promotes the accelerated movement of carriers between the first initial electrode and the solar cell substrate. This not only helps to more effectively break the potential barrier at the interface, promotes the mutual diffusion between metal atoms and silicon atoms, thereby forming a better ohmic contact, but also helps to promote the nucleation and growth of metal grains, forming larger grains, and improving the conductivity of the electrode. In combination with the lower reverse bias in the subsequent continuous moving irradiation process, it can not only finely adjust the ohmic contact that has been initially formed, further optimize the flatness and stability of the contact interface, but also control the further growth of metal grains, and improve the surface roughness and unevenness of the first electrode formed due to the excessive size of the metal grains. In this way, by setting different reverse biases, it can be flexibly adjusted according to different manufacturing stages and material properties of solar cells.

[0104] It can be understood that for different types and thicknesses of the first initial electrode, the reverse bias of the laser can be flexibly adjusted as needed. For example, for some metal electrode materials with higher melting points, sintering can be promoted by a higher initial reverse bias. For another example, for a more fragile substrate, a lower subsequent reverse bias can reduce damage to the substrate. In this way, process flexibility and adaptability can be improved.

[0105] The first initial electrode forms a certain metal composite with the aforementioned doping layer, and combined with the reverse bias voltage reduced in the subsequent continuous moving irradiation process, the contact between the first initial electrode and the doping layer can be further and more accurately controlled to form the desired first electrode. This is conducive to controlling and improving the contact performance of the first electrode.

[0106] In some embodiments, the power of the laser in the first continuous motion irradiation process is greater than that in any continuous motion irradiation process except the first continuous motion irradiation process.

[0107] Since a larger laser power can provide a higher energy input in a shorter time, accelerate the solidification of the first initial electrode and promote the mutual diffusion between the first initial electrode and the doping layer, the first initial electrode can form a certain metal composite with the aforementioned doping layer through the first continuous moving irradiation process, and the organic matter and volatile matter in the first initial electrode can be removed more quickly, and the situation of bubbles and defects generated in the subsequent continuous moving irradiation process can be improved. In combination with the lower laser power in the subsequent continuous moving irradiation process, the grain growth of the first initial electrode can be controlled to make it more uniform and fine, further optimize the contact interface, reduce interface defects and recombination centers, and improve the conductivity and stability of the formed first electrode. In this way, the first initial electrode can be adjusted and optimized more finely.

[0108] It can be understood that for first initial electrodes of different types and thicknesses, the power of the laser can be flexibly adjusted as needed. For example, for a thicker first initial electrode, the power of the laser can be higher during the first continuous moving irradiation process to improve the sintering adequacy. For another example, for a first initial electrode that is sensitive to temperature, the power of the laser can be reduced during the subsequent continuous moving irradiation process to improve the situation of overheating damage. In this way, the process window and the adaptability of the process can be expanded.

[0109] In some embodiments, in all the continuous moving irradiation processes except the first continuous moving irradiation process, the laser used is configured as a red laser. Exemplarily, the laser used in the first continuous moving irradiation process may be a green laser, an ultraviolet laser or other lasers, which not only have high energy, but are also easy to obtain and have low cost.

[0110] Since the energy of red laser is relatively low compared to some high-energy lasers, using red laser in the subsequent continuous moving irradiation process can improve the situation of causing excessive damage to the formed structure or damaging the solar cell substrate.

[0111] The above-illustrated implementation of controlling the reverse bias voltage of the laser and the power of the laser, as well as the implementation of configuring the laser type, can be simultaneously adopted, thereby improving the performance of the manufactured solar cell through the mutual coordination of each continuous moving irradiation process.

[0112] In some embodiments, the irradiation area formed by each continuous moving irradiation process is the same area.

[0113] In this way, it is not only convenient to control the continuous moving irradiation process of the laser, but also beneficial to configure the required continuous moving irradiation process according to the area, thereby manufacturing the required first electrode.

[0114] In some embodiments, different irradiation areas exist in the irradiation areas formed by all the continuous moving irradiation processes.

[0115] In this way, different continuous moving irradiation processes can be configured according to the different states of each region during the process of manufacturing the first electrode, which is beneficial to further improve the performance of the solar cell as a whole.

[0116] Fig.15 A schematic diagram of a first target area z1 on a solar cell substrate 110 provided in some embodiments of the present application is shown; for ease of explanation, only the contents related to the embodiments of the present application are shown. For ease of illustrating the first target area z1, the related electrodes are not shown.

[0117] In some embodiments, please refer to Fig.15 , there is a first target area Z1 in all irradiation areas. The first target area Z1 is determined based on the position of the first initial electrode. That is, the first target area Z1 at least includes at least a part of the area where the first initial electrode is located.

[0118] Specifically, the first target area Z1 may be formed when the first continuous moving irradiation process illustrated above is a non-target irradiation process. Fig.15 For example, it is illustrated that the first target area Z1 includes the area where the first initial electrode is located and the area near the area where the first initial electrode is located. The first target area Z1 roughly corresponds to the first initial electrode one by one. At this time, the first target area Z1 includes all areas where the first initial electrode is located.

[0119] In this way, the first target area is determined by the position of the first initial electrode, so that the laser-assisted sintering can be performed on the first initial electrode in a more targeted manner, which is beneficial to improving the contact performance between the formed first electrode and the doping layer.

[0120] Fig.16The schematic diagram of the relationship between the solar cell substrate 110 and the second target area Z2 provided by some embodiments of the present application is shown; for the convenience of explanation, only the content related to the embodiments of the present application is shown. For the convenience of showing the second target area, the related electrodes are not shown.

[0121] In some embodiments, please refer to Fig.16 , there is a second target area Z2 in all irradiation areas. The second target area Z2 is determined based on the corresponding area of ​​the surface of one side of the solar cell substrate 110 where the first electrode is located. The corresponding area includes at least one of the poorly sintered area of ​​the first initial electrode and the edge area of ​​the solar cell substrate. Fig.16 As an example, the second target area Z2 is illustrated as an edge area of ​​the solar cell substrate 110 .

[0122] In the process of forming the first electrode, there may be a situation where a certain area of ​​the first initial electrode is poorly sintered. In this case, the second target area can be set based on the poorly sintered area of ​​the first initial electrode, and then the defective area of ​​the first initial electrode can be laser-assisted sintered in a targeted manner to improve the sintering yield of the first initial electrode.

[0123] When the first initial electrode is printed by screen printing, it is easy to have too much slurry printed in the edge area of ​​the solar cell substrate, which makes the sintering effect of the edge area different from that of the middle area, making it difficult to control the sintering process. In this case, the second target area can be set based on the edge area of ​​the solar cell substrate, and then the laser-assisted sintering can be carried out in a targeted manner on the area where the sintering effect is difficult to control, thereby improving the sintering effect of the edge area of ​​the solar cell substrate.

[0124] In some embodiments, the order of all irradiation areas formed by the execution order of all continuous moving irradiation processes is a preset order, wherein the sorting number corresponding to the second target area is the middle number; or, the sorting number corresponding to the second target area is the first number; or, the sorting number corresponding to the second target area is the last number.

[0125] That is, the sorting sequence number of the irradiation area formed by the first continuous moving irradiation process is one, the sorting sequence number of the irradiation area formed by the second continuous moving irradiation process is two, and so on. In the case where the sorting sequence number corresponding to the second target area is an intermediate sequence number, the number of continuous moving irradiation processes is at least three, and the irradiation area formed by any continuous moving irradiation process except the first continuous moving irradiation process and the last continuous moving irradiation process includes the second target area. In the case where the sorting sequence number corresponding to the second target area is the first sequence number, the irradiation area formed by the first continuous moving irradiation process includes the second target area. In the case where the sorting sequence number corresponding to the second target area is the last sequence number, the irradiation area formed by the last continuous moving irradiation process includes the second target area.

[0126] For example, after forming the first initial electrode through the metallization heat treatment process, the second target area can be determined according to the detection results, and the sintering effect of the second target area can be improved through the first continuous moving irradiation process. For another example, after any continuous moving irradiation process, the second target area can be determined according to the detection results, and then the continuous moving irradiation process can be performed to improve the sintering effect of the second target area. For another example, after all the continuous moving irradiation processes are completed, the second target area can be determined according to the detection results, and then laser-assisted sintering can be performed to improve the sintering effect of the second target area. The sintering effect of the second target area can be improved according to the specific usage and the specific configuration of the process, which is not specifically limited here.

[0127] In some embodiments, please refer to Figure 7 , Fig.13 and Fig.14 , the angle between the moving direction M of the laser during the target irradiation process and the longitudinal extension direction of the first electrode E1 is 45° to 135°. That is, the angle between the moving direction M of the laser during the target irradiation process and the longitudinal extension direction of the first electrode E1 is the first angle ɵ, and the first angle ɵ is 45° to 135°.

[0128] For example, the first angle ɵ may be 45°, 55°, 65°, 80°, 90°, 100°, 110°, 120° or 135°. Figure 7 and Fig.13 As an example, the case where the first angle ɵ is 90° is shown. Fig.14 As an example, the case where the first angle ɵ is 135° is shown. Fig.14 The first angle ɵ formed by the moving direction opposite to the moving direction M in the embodiment and the longitudinal extension direction of the first electrode E1 is 45°. In the actual implementation process, the first angle ɵ can be any angle within the range.

[0129] Understandably, based on the adoption Figure 7 and Fig.13 In the two continuous moving irradiation processes corresponding to the illustrated situation, the moving directions M of the laser in the two continuous moving irradiation processes are opposite, that is, it can be understood that there are multiple moving directions with opposite directions in the moving direction set illustrated in some of the aforementioned embodiments.

[0130] In this way, the required first angle can be flexibly set according to actual use. When the first angle ɵ is 45° to 135°, the processing effect can be improved in combination with the shape of the solar cell substrate while performing laser assisted sintering.

[0131] In some embodiments, the reverse bias voltage of the laser is 10 V to 30 V, the power of the laser is 10 W to 100 W, and the scanning speed of the laser is 20000 mm / s to 200000 mm / s.

[0132] Exemplarily, the reverse bias voltage of the laser can be 10V, 12V, 15V, 16V, 17V, 19V, 21V, 25V or 30V, the power of the laser can be 10W, 13W, 16W, 18W, 20W, 25W, 30W, 40W, 50W, 70W, 80W, 90W or 100W, and the scanning speed of the laser can be 20000mm / s, 30000mm / s, 50000mm / s, 80000mm / s, 110000mm / s, 150000mm / s, 180000mm / s or 200000mm / s. In the actual implementation process, the reverse bias voltage of the laser, the power of the laser and the scanning speed of the laser can be any angle within the range.

[0133] In this way, controlling the reverse bias of the laser is not only beneficial to reducing the recombination probability of carriers, but also reduces the risk of damaging the solar cell substrate. Controlling the power of the laser is not only beneficial to the short-term temperature rise inside the first initial electrode, but also reduces the risk of overburning of the first initial electrode, thereby reducing the risk of damaging the solar cell substrate. Controlling the scanning speed of the laser can reduce the risk of damaging the solar cell substrate due to excessive thermal effects while maintaining a certain efficiency. In this way, the reverse bias of the laser, the power of the laser and the scanning speed of the laser can be flexibly set in different continuous moving irradiation processes, and the use requirements of different continuous moving irradiation processes can be met through the mutual coordination of the three.

[0134] In some embodiments, please continue to refer to 9 and Fig.10 The same irradiation area W formed by the same continuous moving irradiation process is continuously extended or discontinuously extended.

[0135] Specifically, the laser in the continuous moving irradiation process can be configured as multiple lasers, each laser moving and irradiating on the solar cell substrate to form an irradiation area, and the irradiation area formed in the same continuous moving irradiation process is composed of the irradiation areas formed by all laser moving irradiations.

[0136] It should be noted that multiple light emitting devices can be integrated into the same laser to emit lasers, or multiple lasers can emit lasers separately. Among them, multiple lasers can be arranged side by side or according to the required light emission pattern, which is not specifically limited here. To facilitate the description of the corresponding continuous moving irradiation process, the above schematic diagram Figure 7 , Figure 12 to Figure 14 , is only for a continuous moving irradiation process, and for the sake of ease of understanding, the first electrode E1 is illustrated, and the following illustrated Fig.17 , can also be understood in the same way. In the same continuous moving irradiation process, each laser can be emitted at the same time or at different times. Regardless of whether each laser is emitted at the same time or at different times, the emission of the corresponding laser can be controlled according to the required irradiation area. For example, in the case where the same irradiation area is extended intermittently, the laser corresponding to the irradiation area can be emitted intermittently. For different continuous moving irradiation processes, the corresponding laser emission process can be configured according to the graphics formed by the irradiation areas required in different processes and the different moving irradiation sequences. The graphics formed by the irradiation areas required in different processes can be pre-set in the control program, or can be set according to the detection results as mentioned in some of the aforementioned embodiments, and no specific restrictions are made here. It can be understood that the first target area and the second target area mentioned above can also be configured in this way.

[0137] For example, Fig.14 and Fig.17 For example, Fig.17 Schematic diagram showing a moving irradiation path P provided in some embodiments of the present application, Fig.14 The moving directions M and Fig.17 The moving direction M shown in FIG. is the same direction. Fig.14 In the illustrated case, multiple lasers can be emitted simultaneously. Fig.14 In terms of Fig.17 In the illustrated case, the laser can be emitted according to the preset pattern mentioned above. At this time, it can be roughly regarded as emitting laser based on the boundary defined by the outline of the solar cell substrate. Of course, according to different mobile irradiation sequences and mobile irradiation processes, the preset pattern can also be other situations, which are not specifically limited here.

[0138] In this way, by extending the irradiation area continuously or intermittently, not only can the needs of different continuous mobile irradiation processes be flexibly met, but also the laser cost can be saved and the work efficiency can be improved.

[0139] In some embodiments, the laser is controlled to continuously move and irradiate the solar cell substrate twice.

[0140] In this way, the sintering effect can be improved while reducing the use cost and improving the work efficiency.

[0141] Of course, in some other embodiments, the number of times of controlling the laser to perform continuous moving irradiation on the solar cell substrate may be three times, four times or other times, which is not specifically limited here.

[0142] Fig.18 A flow chart of step S130 in a method for manufacturing a solar cell provided in some embodiments of the present application is shown; for ease of explanation, only contents related to the embodiments of the present application are shown.

[0143] In some embodiments, please refer to Fig.18 , step S130 includes the following steps:

[0144] Step S131, providing a laser; the laser is located on one side of the thickness direction of the solar cell substrate and is arranged opposite to the central area of ​​the solar cell substrate;

[0145] Step S132: Control the laser to rotate so that the moving irradiation area of ​​the laser emitted by the laser can cover at least a portion of the solar cell substrate, so as to perform laser-assisted sintering on the first initial electrode to form the first electrode.

[0146] For example, referring to FIG. Figure 6 and Figure 8 The laser Q is located above the solar cell substrate 110 and is arranged exactly at the center of the solar cell substrate 110 .

[0147] In this way, by controlling the laser in a rotational manner, the error of the irradiation area formed in the continuous moving irradiation process can be reduced, which is beneficial to improving the accuracy of laser-assisted sintering, thereby helping to improve the sintering effect.

[0148] In the following, in combination with the above-mentioned embodiments and related comparative examples, the solar cell manufactured by the method for manufacturing a solar cell provided in the embodiments of the present application is exemplarily described.

[0149] by Fig.19Taking the structure of the solar cell 100 shown as an example, the solar cell 100 includes a solar cell 100 substrate 111, a first electrode E1 and a second electrode E2. The solar cell 100 substrate 111 includes a substrate 111, a doping layer 112, a first passivation layer 113, a tunneling layer 114, a doped conductive layer 115 and a second passivation layer 116. The doping layer 112, the first passivation layer 113 and the first electrode E1 are sequentially arranged on the first surface m1 side of the substrate 111, and the first electrode E1 and the doping layer 112 are in ohmic contact. The tunneling layer 114, the doped conductive layer 115, the second passivation layer 116 and the second electrode E2 are sequentially arranged on the second surface m2 side of the substrate 111, and the second electrode E2 and the doped conductive layer 115 are in ohmic contact. Among them, the substrate 111 is an N-type substrate with a thickness of 0.15nm; the doping layer 112 is made of boron-doped single crystal silicon with a thickness of 1000nm; the first passivation layer 113 is made of Si x O y N z , with a thickness of 80 nm; the material of the tunneling layer 114 is Si x O y , with a thickness of 1.2nm; the material of the doped conductive layer 115 is phosphorus-doped polysilicon, with a thickness of 100nm; the material of the second passivation layer 116 is Si x N y , thickness is 100nm; the material of the first electrode E1 is Ag, the width is 20µm, and the number of roots is 150; the material of the second electrode E2 is Ag, the width is 40µm, and the number of roots is 200.

[0150] In Example 1, after the first initial electrode is formed by the metallization heat treatment process, the laser is controlled to perform continuous moving irradiation on the solar cell substrate 110 twice. The moving direction M of the laser in the first continuous moving irradiation process is set at 90° to the longitudinal extension direction of the first electrode E1, the reverse bias of the laser is 10V, the power of the laser is 100W, and the scanning speed of the laser is 20000mm / s. The moving direction M of the laser in the second continuous moving irradiation process is set at 90° to the longitudinal extension direction of the first electrode E1, the reverse bias of the laser is 30V, the power of the laser is 10W, and the scanning speed of the laser is 200000mm / s.

[0151] In Example 2, after the first initial electrode is formed by the metallization heat treatment process, the laser is controlled to perform continuous moving irradiation on the solar cell substrate 110 twice. The moving direction M of the laser in the first continuous moving irradiation process is set at 45° to the longitudinal extension direction of the first electrode E1, the reverse bias of the laser is 15V, the power of the laser is 50W, and the scanning speed of the laser is 100000mm / s. The moving direction M of the laser in the second continuous moving irradiation process is set at 45° to the longitudinal extension direction of the first electrode E1, the reverse bias of the laser is 15V, the power of the laser is 50W, and the scanning speed of the laser is 100000mm / s.

[0152] In Example 3, after the first initial electrode is formed by the metallization heat treatment process, the laser is controlled to perform continuous moving irradiation on the solar cell substrate 110 twice. The moving direction of the laser in the first continuous moving irradiation process is set at 90° to the longitudinal extension direction of the first electrode, the reverse bias of the laser is 30V, the power of the laser is 10W, and the scanning speed of the laser is 200000mm / s. The moving direction of the laser in the second continuous moving irradiation process is set at 45° to the longitudinal extension direction of the first electrode, the reverse bias of the laser is 15V, the power of the laser is 10W, and the scanning speed of the laser is 50000mm / s.

[0153] In Example 4, after the first initial electrode is formed by the metallization heat treatment process, the laser is controlled to perform continuous moving irradiation on the solar cell substrate 110 once. The moving direction M of the laser during the continuous moving irradiation is set at 90° to the longitudinal extension direction of the first electrode E1, the reverse bias voltage of the laser is 15V, the power of the laser is 15W, and the scanning speed of the laser is 50000mm / s.

[0154] In Example 5, after the first initial electrode is formed by the metallization heat treatment process, the laser is controlled to perform continuous moving irradiation on the solar cell substrate 110 twice. The moving direction M of the laser in the first continuous moving irradiation process is parallel to the longitudinal extension direction of the first electrode E1, the reverse bias of the laser is 15V, the power of the laser is 15W, and the scanning speed of the laser is 100000mm / s. The moving direction M of the laser in the second continuous moving irradiation process is set at 90° to the longitudinal extension direction of the first electrode E1, the reverse bias of the laser is 15V, the power of the laser is 15W, and the scanning speed of the laser is 100000mm / s.

[0155] In comparative example 1, after the first initial electrode is formed by the metallization heat treatment process, the laser is controlled to perform continuous moving irradiation on the solar cell substrate 110 once. The moving direction M of the laser in the continuous moving irradiation process is parallel to the longitudinal extension direction of the first electrode E1, the reverse bias voltage of the laser is 15V, the power of the laser is 15W, and the scanning speed of the laser is 100000mm / s. The irradiation area formed by the continuous moving irradiation process is set based on the first initial electrode area.

[0156] In comparative example 2, after the first initial electrode is formed by the metallization heat treatment process, the laser is controlled to perform continuous moving irradiation on the solar cell substrate 110 twice. The moving direction M of the laser in the first continuous moving irradiation process is parallel to the longitudinal extension direction of the first electrode E1, the reverse bias of the laser is 15V, the power of the laser is 15W, and the scanning speed of the laser is 100000mm / s. The moving direction M of the laser in the second continuous moving irradiation process is parallel to the longitudinal extension direction of the first electrode E1, the reverse bias of the laser is 15V, the power of the laser is 15W, and the scanning speed of the laser is 100000mm / s. The irradiation area formed by the two continuous moving irradiation processes is set based on the first initial electrode area.

[0157] The solar cells manufactured in the above-mentioned embodiments and comparative examples were tested for power using a digital source meter under AM1.5G simulated sunlight at 25 degrees Celsius. The test results are shown in Table 1.

[0158] Table 1

[0159]

[0160] It can be seen from Table 1 that compared with Comparative Example 1, Example 4 is also laser irradiated once, and the moving direction M of the laser is perpendicular to the longitudinal extension direction of the first electrode E1. The conversion efficiency of the solar cell in Example 4 is increased by 0.04%. Compared with Comparative Example 1, Example 1, Example 2, Example 3, and Example 5 are all laser irradiated twice, and at least one of the moving directions M of the laser is not parallel to the longitudinal extension direction of the first electrode E1, so that the conversion efficiency of the solar cell is increased by more than 0.06%. Compared with Comparative Example 2, Example 1, Example 2, Example 3, and Example 5 are all laser irradiated twice, and at least one of the moving directions M of the laser is not parallel to the longitudinal extension direction of the first electrode E1, so that the conversion efficiency of the solar cell is increased by more than 0.04%. Among them, compared with Comparative Example 2, the laser was only irradiated once in Example 4, and the conversion efficiency of the solar cell provided in Example 4 was increased by 0.02%. It can be seen that the conversion efficiency of the solar cell provided in the embodiment of the present application is improved.

[0161] Based on the same inventive concept, an embodiment of the present application provides a solar cell, which is manufactured by the solar cell manufacturing method in any of the above embodiments.

[0162] It should be noted that the solar cell can be a TOPCon cell, a BC cell or other types of cells, which are not specifically limited here. The solar cell may be provided with a main grid electrode or may not be provided with a main grid electrode, which is not specifically limited here. Figure 7 , Fig.12 , Fig.13 , Fig.14 and Fig.17 , a situation where a main grid line electrode (not shown) is provided is illustrated.

[0163] The advantages of the above-mentioned method for manufacturing a solar cell are also possessed by the solar cell, which will not be described in detail here.

[0164] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0165] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for manufacturing a solar cell, characterized in that: include: providing a solar cell substrate; Forming a first initial electrode on the solar cell substrate by a metallization heat treatment process; Controlling the laser to move and irradiate on the solar cell substrate to perform laser-assisted sintering on the first initial electrode to form a first electrode, thereby obtaining the solar cell; Wherein, the laser is controlled to perform continuous moving irradiation on the solar cell substrate at least once; There is a target irradiation process in all continuous moving irradiation processes. In the target irradiation process, the moving direction of the laser on the solar cell substrate and the longitudinal extension direction of the first electrode intersect each other, and the moving direction of the laser on the solar cell substrate and the longitudinal extension direction of the first electrode are both perpendicular to the thickness direction of the solar cell substrate.

2. The method for manufacturing a solar cell according to claim 1, characterized in that: Controlling the laser to continuously move and irradiate on the solar cell substrate multiple times; Wherein, the moving direction of the laser in the first continuous moving irradiation process is parallel to the longitudinal extension direction of the first electrode; or The first continuous moving irradiation process is the target irradiation process.

3. The method for manufacturing a solar cell according to claim 2, characterized in that: The laser is controlled to perform continuous moving irradiation on the solar cell substrate at least three times; all the continuous moving irradiation processes except the first continuous moving irradiation process are the target irradiation processes; the moving directions of the laser on the solar cell substrate in all the target irradiation processes constitute a moving direction set; The moving direction set includes a plurality of moving directions with the same direction or a plurality of moving directions with opposite directions; or In the moving direction set, there are multiple moving directions that intersect with each other.

4. The method for manufacturing a solar cell according to claim 2, characterized in that: The reverse bias voltage of the laser in the first continuous moving irradiation process is greater than any continuous moving irradiation process in all the continuous moving irradiation processes except the first continuous moving irradiation process; and / or The power of the laser in the first continuous moving irradiation process is greater than that in any of the continuous moving irradiation processes except the first continuous moving irradiation process; and / or In all the continuous moving irradiation processes except the first continuous moving irradiation process, the laser used is configured as a red light laser.

5. The method for manufacturing a solar cell according to claim 2, characterized in that: The irradiation area formed by each continuous moving irradiation process is the same area.

6. The method for manufacturing a solar cell according to claim 2, characterized in that: There are different irradiation areas in the irradiation areas formed by all the continuous moving irradiation processes.

7. The method for manufacturing a solar cell according to claim 6, characterized in that: A second target area exists in all the irradiated areas; The second target area is determined based on a corresponding area of ​​a side surface of the solar cell substrate where the first initial electrode is located; the corresponding area includes at least one of a poorly sintered area of ​​the first initial electrode and an edge area of ​​the solar cell substrate.

8. The method for manufacturing a solar cell according to claim 7, characterized in that: The order of all the irradiation areas formed by the execution order of all the continuous moving irradiation processes is a preset order; The sorting sequence number corresponding to the second target area is an intermediate sequence number; or The sorting sequence number corresponding to the second target area is the first sequence number; or The sorting sequence number corresponding to the second target area is the last sequence number.

9. The method for manufacturing a solar cell according to any one of claims 1 to 8, characterized in that: The angle between the moving direction of the laser during the target irradiation process and the longitudinal extension direction of the first electrode is 45° to 135°; and / or The reverse bias voltage of the laser is 10V to 30V, the power of the laser is 10W to 100W, and the scanning speed of the laser is 20000mm / s to 200000mm / s; and / or The same irradiation area formed by the same continuous moving irradiation process is extended continuously or discontinuously; and / or The laser is controlled to perform continuous moving irradiation on the solar cell substrate twice.

10. The method for manufacturing a solar cell according to any one of claims 1 to 8, characterized in that: The control laser is moved and irradiated on the solar cell substrate to perform laser-assisted sintering on the first initial electrode to form a first electrode, thereby obtaining the solar cell, comprising: Providing a laser; the laser is located on one side of the thickness direction of the solar cell substrate and is arranged opposite to the central area of ​​the solar cell substrate; The laser is controlled to rotate so that the moving irradiation area of ​​the laser emitted by the laser can cover at least a portion of the solar cell substrate, so as to perform laser-assisted sintering on the first preliminary electrode to form the first electrode.

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