Laser-assisted sintering method, crystalline silicon solar cell and photovoltaic module

Abstract

The invention provides a laser-assisted sintering method, a crystalline silicon solar cell and a photovoltaic module, and relates to the technical field of crystalline silicon solar cells. The laser-assisted sintering method comprises the steps that a to-be-sintered area of the crystalline silicon solar cell is divided into N equal parts in the direction perpendicular to a fine grid line, the first to Nth to-be-sintered areas which are arranged in sequence are obtained, and N is a positive integer larger than or equal to 4; and laser is adopted to irradiate the metal grid lines on all the to-be-sintered areas, and bias voltage is loaded on the metal grid lines on all the to-be-sintered areas so that the metal grid lines can be sintered. The crystalline silicon solar cell prepared with the metal grid lines is divided into a plurality of to-be-sintered areas, the bias voltage and the laser output power of each to-be-sintered area are controlled, the sintering effect of the metal grid lines can be effectively improved, the crystalline silicon solar cell forms good ohmic contact, and therefore the photoelectric conversion efficiency of the crystalline silicon solar cell is improved.

Description

Technical Field

[0001] The present application relates to the technical field of crystalline silicon solar cells, and in particular to a laser-assisted sintering method, a crystalline silicon solar cell and a photovoltaic module. Background Art

[0002] The sintering processes of crystalline silicon solar cells mainly include: traditional sintering method and laser sintering method. The traditional sintering method is: first screen print the metal grid line, and then perform high-temperature sintering; after high-temperature sintering, the metal grid line forms contact with silicon to realize the collection and output of photogenerated carriers. However, the crystalline silicon solar cells sintered at high temperature in the traditional sintering furnace cannot form a good ohmic contact, and the excessively high sintering temperature is prone to problems such as cell deformation and high fragmentation rate, thereby reducing the photoelectric conversion efficiency of the crystalline silicon solar cell. The laser sintering method is: the induced carriers are formed by the local laser beam, combined with the bias voltage, to form a local current; the priority path of the local current is a low-resistance path, which must already exist between the emitter and Ag under the grid line, and leads to a high current density; the high current density causes sintering at the corresponding point of the hot spot, causing mutual diffusion of silver and silicon, affecting the photoelectric efficiency. In addition, the square resistance and film thickness of the cell are non-uniform, resulting in poor sintering effect, thereby reducing the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0003] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present application is to provide a laser-assisted sintering method, a crystalline silicon solar cell and a photovoltaic module, which divides the crystalline silicon solar cell prepared with metal grid lines into more than 4 areas to be sintered, controls the bias voltage and laser output power of each area to be sintered, can effectively improve the sintering effect of the metal grid lines, and enable the crystalline silicon solar cell to form a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0005] To achieve the above objectives, this application adopts the following technical solutions: A laser-assisted sintering method, comprising: Dividing the sintering area of ​​the crystalline silicon solar cell into N equal parts along a direction perpendicular to the fine grid lines, to obtain the first to Nth sintering areas arranged in sequence, wherein N is a positive integer ≥ 4; metal grid lines are prepared on the sintering areas, and the metal grid lines include the fine grid lines; Using laser to irradiate the metal grid lines on each area to be sintered, and applying bias voltage to the metal grid lines in each area to be sintered, so as to sinter the metal grid lines; Wherein, the bias voltage of the first zone to be sintered is greater than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the first zone to be sintered is greater than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; The bias voltage of the Nth zone to be sintered is greater than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the Nth zone to be sintered is greater than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered.

[0006] In some embodiments, N is equal to 4, 6 or 8.

[0007] In some embodiments, the bias voltage of the first zone to be sintered is 2-4V higher than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the first zone to be sintered is 10-20% higher than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; and / or The bias voltage of the Nth zone to be sintered is 2~4V higher than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the Nth zone to be sintered is 10~20% higher than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered.

[0008] In some embodiments, the bias voltage on the first sintering area is 16-22V; and / or The bias voltage on any area to be sintered between the first area to be sintered and the Nth area to be sintered is 14-18V; and / or The bias voltage on the Nth area to be sintered is 16-22V.

[0009] In some embodiments, the laser output power of the first sintering zone is 84.0-93.5 W, and the frequency of the laser is 45-55 kHz; and / or On any area to be sintered between the first area to be sintered and the Nth area to be sintered, the output power of the laser is 72.00-80.75 W, and the frequency of the laser is 45-55 kHz; and / or The laser output power of the Nth area to be sintered is 84.0-93.5 W, and the frequency of the laser is 45-55 kHz.

[0010] In some embodiments, the laser output power of the first sintering zone is 84-87W, and the frequency of the laser is 45-55kHz; and / or On any area to be sintered between the first area to be sintered and the Nth area to be sintered, the output power of the laser is 72.00-80.75 W, and the frequency of the laser is 45-55 kHz; and / or The laser output power of the Nth area to be sintered is 90-93W, and the frequency of the laser is 45-55kHz.

[0011] In some embodiments, on the first sintering area, the scanning speed of the laser is 75000-80000 mm / s; On any sintering area between the first sintering area and the Nth sintering area, the scanning speed of the laser is 58000-60000 mm / s; On the Nth area to be sintered, the scanning speed of the laser is 75000-80000 mm / s.

[0012] In some embodiments, on the first sintering area, the scanning speed of the laser is 78000-80000 mm / s; On any sintering area between the first sintering area and the Nth sintering area, the scanning speed of the laser is 58000-60000 mm / s; On the Nth area to be sintered, the scanning speed of the laser is 75000-77000 mm / s.

[0013] The present application also provides a crystalline silicon solar cell, the metal grid lines of the crystalline silicon solar cell are prepared by the above-mentioned laser-assisted sintering method.

[0014] The present application also provides a photovoltaic module, comprising the above-mentioned crystalline silicon solar cell.

[0015] In the technical solution of the present application, the crystalline silicon solar cell prepared with metal grid lines is divided into multiple sintering areas, and the bias voltage and laser output power of each sintering area are controlled, which can effectively improve the sintering effect of the metal grid lines and enable the crystalline silicon solar cell to form a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application. Figure 1 This is a schematic diagram of the sintering area of ​​a crystalline silicon solar cell in an existing laser-assisted sintering method.

[0017] Figure 2 This is a schematic diagram of the division of the to-be-sintered area of ​​a crystalline silicon solar cell according to an embodiment of the laser-assisted sintering method of the present application. DETAILED DESCRIPTION

[0018] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. Wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limitations on the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0019] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not mean that the present disclosure necessarily has the first element, component, region, layer or part.

[0020] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; 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 defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0021] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0022] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0023] The embodiments of the present application aim to provide a laser-assisted sintering method, a crystalline silicon solar cell and a photovoltaic module, which divides a crystalline silicon solar cell prepared with a metal grid line into more than four sintering areas, controls the bias voltage and laser output power of each sintering area, can effectively improve the sintering effect of the metal grid line, and enable the crystalline silicon solar cell to form a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0024] The present application provides a laser-assisted sintering method, comprising: Dividing the sintering area of ​​the crystalline silicon solar cell into N equal parts along a direction perpendicular to the fine grid lines, to obtain the first to Nth sintering areas arranged in sequence, wherein N is a positive integer ≥ 4; metal grid lines are prepared on the sintering areas, and the metal grid lines include the fine grid lines; Using laser to irradiate the metal grid lines on each area to be sintered, and applying bias voltage to the metal grid lines in each area to be sintered, so as to sinter the metal grid lines; Wherein, the bias voltage of the first zone to be sintered is greater than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the first zone to be sintered is greater than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; The bias voltage of the Nth zone to be sintered is greater than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the Nth zone to be sintered is greater than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered.

[0025] In the embodiment of the present application, the crystalline silicon solar cell may be a monocrystalline silicon solar cell or a polycrystalline silicon solar cell.

[0026] In the embodiment of the present application, the method for preparing the metal grid lines of the crystalline silicon solar cell can be selected from one or more of the following: screen printing, electroplating, inkjet printing, and biomimetic preparation. The slurry used to prepare the metal grid lines can be selected from one or more of the following: silver paste, silver-aluminum paste, copper paste, and silver-coated copper paste. The metal grid lines can be prepared on the front or back of the crystalline silicon solar cell, or on both the front and back of the crystalline silicon solar cell, and then the metal grid lines can be sintered.

[0027] In the embodiment of the present application, N can be 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16. Taking N equal to 4 as an example, see Figure 2, the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in equal parts. The bias voltages loaded in the first sintering area, the second sintering area, the third sintering area, and the fourth sintering area are recorded as V1, V2, V3, and V4 respectively; V1, V2, V3, and V4 satisfy: V1>V2, V1>V3; V4>V2, V4>V3; V2 and V3 can be equal, and V2 and V3 can also be different; V1 and V4 can be equal, and V1 and V4 can also be different. The output power of the laser used in the first sintering area, the second sintering area, the third sintering area, and the fourth sintering area is recorded as P1, P2, P3, and P4 respectively. P1, P2, P3, and P4 satisfy the following conditions: P1>P2, P1>P3; P4>P2, P4>P3; P2 and P3 can be equal, or P2 and P3 can be unequal; P1 and P4 can be equal, or P1 and P4 can be unequal. When N is other values, the size relationship between the process parameters of each area to be sintered can refer to the size relationship between the parameters of each area to be sintered when N is equal to 4, which will not be repeated here. That is, the present application controls the voltage and laser output power of the first area to be sintered and the Nth area to be sintered to be slightly higher than that of other areas to be sintered, which effectively improves the sintering effect of the metal grid line, enables the crystalline silicon solar cell to form a good ohmic contact, and thus improves the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0028] In the embodiment of the present application, taking the TOPCon battery as an example, the fine grid lines of the TOPCon battery cell are printed along the length direction of the battery cell, arranged in the form of parallel lines, and fill the entire front of the battery cell; therefore, the entire front of the TOPCon battery is the area to be sintered. The area to be sintered is divided into N equal parts along the direction perpendicular to the fine grid lines (the width direction of the battery cell), and then the bias voltage and laser output power of each area to be sintered are controlled. Other types of crystalline silicon batteries are similar. Other types of crystalline silicon batteries are generally covered with metal grid lines (including fine grid lines) on the front or back of the battery cell. It is only necessary to divide the area to be sintered into N equal parts along the direction perpendicular to the fine grid lines, and then control the bias voltage and laser output power of each area to be sintered.

[0029] In the embodiment of the present application, controlling the bias voltage and laser output power of each area to be sintered can effectively improve the sintering effect of the metal grid line, so that the crystalline silicon solar cell forms a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0030] In an optional embodiment, N is equal to 4, 6 or 8. The surface area of ​​the crystalline silicon solar cell prepared with metal grid lines is recorded as S'. When N is equal to 4, the area of ​​the first area to be sintered is 1 / 4S', and the area of ​​the fourth area to be sintered is 1 / 4S'; when N is equal to 6, the area of ​​the first area to be sintered is 1 / 6S', and the area of ​​the fourth area to be sintered is 1 / 6S'; when N is equal to 8, the area of ​​the first area to be sintered is 1 / 8S', and the area of ​​the fourth area to be sintered is 1 / 8S'; controlling the numerical value of N, that is, controlling the proportion of the area of ​​each area to be sintered, when N is equal to 4, 6 or 8, can further improve the sintering effect of the metal grid lines, so that the crystalline silicon solar cell forms a better ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0031] In some embodiments, the bias voltage of the first zone to be sintered is 2-4V higher than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the first zone to be sintered is 10-20% higher than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; and / or The bias voltage of the Nth zone to be sintered is 2~4V higher than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the Nth zone to be sintered is 10~20% higher than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered.

[0032] In the embodiment of the present application, N is taken as an example, and the specific Figure 2, the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in equal parts. The bias voltages loaded on the first sintering area, the second sintering area, the third sintering area, and the fourth sintering area are recorded as V1, V2, V3, and V4 respectively; V1, V2, V3, and V4 satisfy: when V2=V3, V1=V2(V3)+2~4 volts, V4=V2(V3)+2~4 volts; when V2>V3, V1=V2+2~4 volts, V4=V2+2~4 volts; when V2<V3, V1=V3+2~4 volts, V4=V3+2~4 volts. V1 and V4 can be equal, or V1 and V4 can be different. The output powers of the lasers used in the first, second, third and fourth sintering zones are recorded as P1, P2, P3 and P4 respectively. P1, P2, P3 and P4 satisfy the following conditions: when P2=P3, P1=1.1 times of P2~1.2 times of P2, P4=1.1 times of P2~1.2 times of P2; when P2>P3, P1=1.1 times of P2~1.2 times of P2, P4=1.1 times of P2~1.2 times of P2; when P2<P3, P1=1.1 times of P3~1.2 times of P3, P4=1.1 times of P3~1.2 times of P3; P1 and P4 can be equal or different.

[0033] In the embodiment of the present application, the specific values ​​of P1, P2, P3, P4, V1, V2, V3, and V4 can be determined according to the existing process parameters of the crystalline silicon solar cell production line. Figure 1 As shown, in the existing process, the metal grid lines of the crystalline silicon solar cell do not need to be sintered in different zones. The bias voltage loaded on the entire sintering zone of the crystalline silicon solar cell is the same value, and the output power of the laser used in the entire sintering zone is also the same value. The bias voltage loaded on the metal grid line is recorded as V', and the output power of the laser is recorded as P'. Then P1 = 1.05 times P'~1.1 times P', P4 = 1.05 times P'~1.1 times P', P2=0.9 times P'~0.95 times P', P3=0.9 times P'~0.95 times P'; V1=V'+1~2 volts, V4=V'+1~2 volts, V2=V'-1~2 volts, V3=V'-1~2 volts, that is, V2 is 1~2 volts lower than V', V3 is 1~2 volts lower than V', V4 is 1~2 volts higher than V', and V1 is 1~2 volts higher than V'.

[0034] In the embodiment of the present application, the bias voltage and laser output power of each sintering area are further controlled to further improve the sintering effect of the metal grid line, so that the crystalline silicon solar cell forms a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0035] In an optional embodiment, the bias voltage on the first to-be-sintered area is 16-22V (for example, 16V, 17V, 18V, 19V, 20V, 21V, 22V, 23V, 24V); and / or The bias voltage on any area to be sintered between the first area to be sintered and the Nth area to be sintered is 14-18V (for example, 14V, 15V, 16V, 17V, 18V); and / or The bias voltage on the Nth area to be sintered is 16-22V (for example, 16V, 17V, 18V, 19V, 20V, 21V, 22V, 23V, 24V).

[0036] In the embodiment of the present application, the bias voltage of each area to be sintered is reasonably controlled, which can further improve the sintering effect of the metal grid line, so that the crystalline silicon solar cell forms a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0037] In an optional embodiment, the laser output power of the first sintering zone is 84.0-93.5 W (for example, 84 W, 85 W, 86 W, 87 W, 88 W, 89 W, 90 W, 91 W, 92 W, 93 W, 93.5 W), and the frequency of the laser is 45-55 kHz (for example, 45 kHz, 46 kHz, 47 kHz, 48 kHz, 49 kHz, 50 kHz, 51 kHz, 52 kHz, 53 kHz, 54 kHz, 55 kHz); and / or On any area to be sintered between the first area to be sintered and the Nth area to be sintered, the output power of the laser is 72.00-80.75 W (for example, 72 W, 73 W, 74 W, 75 W, 76 W, 77 W, 78 W, 79 W, 80 W, 80.75 W), and the frequency of the laser is 45-55 kHz (for example, 45 kHz, 46 kHz, 47 kHz, 48 kHz, 49 kHz, 50 kHz, 51 kHz, 52 kHz, 53 kHz, 54 kHz, 55 kHz); and / or The laser output power of the Nth area to be sintered is 84.0~93.5W (for example, 84W, 85W, 86W, 87W, 88W, 89W, 90W, 91W, 92W, 93W, 93.5W), and the frequency of the laser is 45~55kHz (for example, 45kHz, 46kHz, 47kHz, 48kHz, 49kHz, 50kHz, 51kHz, 52kHz, 53kHz, 54kHz, 55kHz).

[0038] In the embodiment of the present application, the output power of the laser in each area to be sintered can be reasonably controlled to further improve the sintering effect of the metal grid line, so that the crystalline silicon solar cell forms a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0039] In an optional embodiment, the laser output power of the first sintering zone is 84-87W (for example, 84W, 85W, 86W, 87W), and the frequency of the laser is 45-55kHz (for example, 45kHz, 46kHz, 47kHz, 48kHz, 49kHz, 50kHz, 51kHz, 52kHz, 53kHz, 54kHz, 55kHz); and / or On any area to be sintered between the first area to be sintered and the Nth area to be sintered, the output power of the laser is 72.00-80.75 W (for example, 72 W, 73 W, 74 W, 75 W, 76 W, 77 W, 78 W, 79 W, 80 W, 80.75 W), and the frequency of the laser is 45-55 kHz (for example, 45 kHz, 46 kHz, 47 kHz, 48 kHz, 49 kHz, 50 kHz, 51 kHz, 52 kHz, 53 kHz, 54 kHz, 55 kHz); and / or The laser output power of the Nth area to be sintered is 90~93W (for example, 90W, 91W, 92W, 93W), and the frequency of the laser is 45~55kHz (for example, 45kHz, 46kHz, 47kHz, 48kHz, 49kHz, 50kHz, 51kHz, 52kHz, 53kHz, 54kHz, 55kHz).

[0040] In the embodiment of the present application, the laser output power of each area to be sintered is reasonably controlled, which can further improve the sintering effect of the metal grid line, so that the crystalline silicon solar cell forms a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0041] In an optional embodiment, on the first sintering area, the scanning speed of the laser is 75000-80000 mm / s (for example, 75000 mm / s, 76000 mm / s, 77000 mm / s, 78000 mm / s, 79000 mm / s, 80000 mm / s); On any sintering area between the first sintering area and the Nth sintering area, the scanning speed of the laser is 58000-60000 mm / s (for example, 58000 mm / s, 59000 mm / s, 60000 mm / s); On the Nth area to be sintered, the scanning speed of the laser is 75000-80000 mm / s (for example, 75000 mm / s, 76000 mm / s, 77000 mm / s, 78000 mm / s, 79000 mm / s, 80000 mm / s).

[0042] In the embodiment of the present application, the output power of the laser is reasonably controlled, and at the same time, the laser scanning speed of each area to be sintered is reasonably controlled, which can further improve the sintering effect of the metal grid line, enable the crystalline silicon solar cell to form a good ohmic contact, and thus improve the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0043] In some embodiments, on the first area to be sintered, the scanning speed of the laser is 78000-80000 mm / s (for example, 78000 mm / s, 79000 mm / s, 80000 mm / s); On any sintering area between the first sintering area and the Nth sintering area, the scanning speed of the laser is 58000-60000 mm / s (for example, 58000 mm / s, 59000 mm / s, 60000 mm / s); On the Nth area to be sintered, the scanning speed of the laser is 75000-77000 mm / s (for example, 75000 mm / s, 76000 mm / s, 77000 mm / s).

[0044] In the embodiment of the present application, the output power of the laser is reasonably controlled, and at the same time, the laser scanning speed of each area to be sintered is reasonably controlled, which can further improve the sintering effect of the metal grid line, enable the crystalline silicon solar cell to form a good ohmic contact, and thus improve the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0045] The following specific examples further illustrate the present application, but should not be construed as limiting the present application. Without departing from the spirit and substance of the present application, modifications or replacements made to the methods, steps or conditions of the present application are within the scope of the present application.

[0046] Example 1 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0047] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) Using laser to irradiate the metal grid lines on each of the areas to be sintered, and loading bias voltage on the metal grid lines in each of the areas to be sintered, so as to sinter the metal grid lines; it should be noted that the time of loading the bias voltage is consistent with the time of laser irradiation, that is, the entire process of sintering the metal grid lines requires both loading the bias voltage and laser irradiation, which will be the same below and will not be repeated.

[0048] The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 84 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 75000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 75000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14 volts, laser output power P3 = 72 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 75000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 16 volts, laser output power P4 = 84 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s.

[0049] Example 2 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0050] (2) along the width direction of the crystalline silicon solar cell prepared with metal grid lines (in the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), the fourth sintering area (S4), and the fifth sintering area (S5) in equal parts; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), the fourth sintering area (S4), and the fifth sintering area (S5) are all 210 mm x 42 mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 84 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 75000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 75000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14 volts, laser output power P3 = 72 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 75000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 14 volts, laser output power P4 = 72 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s; The process parameters of the fifth sintering zone are: bias voltage V5 = 16 volts, laser output power P5 = 84 watts, laser frequency F5 = 55 kHz, laser scanning speed W5 = 75000 mm / s.

[0051] Example 3 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0052] (2) along the width direction of the crystalline silicon solar cell prepared with metal grid lines (in the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), the fourth sintering area (S4), the fifth sintering area (S5), and the sixth sintering area (S6) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), the fourth sintering area (S4), the fifth sintering area (S5), and the sixth sintering area (S6) are all 210 mm x 35 mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 84 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 75000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 75000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14 volts, laser output power P3 = 72 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 75000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 14 volts, laser output power P4 = 72 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s; The process parameters of the fifth sintering zone are: bias voltage V5 = 14 volts, laser output power P5 = 72 watts, laser frequency F5 = 55 kHz, laser scanning speed W5 = 75000 mm / s; The process parameters of the sixth sintering zone are: bias voltage V6 = 16 volts, laser output power P6 = 84 watts, laser frequency F6 = 55 kHz, laser scanning speed W6 = 75000 mm / s.

[0053] Example 4 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0054] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 84 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 75000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 75000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14.5 volts, laser output power P3 = 74 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 75000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 16 volts, laser output power P4 = 84 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s.

[0055] Example 5 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0056] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 84 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 75000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 15.5 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 75000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 15.5 volts, laser output power P3 = 72 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 75000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 16 volts, laser output power P4 = 84 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s.

[0057] Example 6 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0058] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 14 volts, laser output power P1 = 84 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 75000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 12 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 75000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 12 volts, laser output power P3 = 72 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 75000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 14 volts, laser output power P4 = 84 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s.

[0059] Example 7 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0060] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 55 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 75000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 50 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 75000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14 volts, laser output power P3 = 50 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 75000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 16 volts, laser output power P4 = 55 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s.

[0061] Example 8 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0062] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 84 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 75000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 75000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14 volts, laser output power P3 = 72 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 75000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 16 volts, laser output power P4 = 90 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s.

[0063] Example 9 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0064] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 87 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 75000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 75000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14 volts, laser output power P3 = 72 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 75000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 16 volts, laser output power P4 = 93 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s.

[0065] Example 10 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0066] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 84 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 75000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 58000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14 volts, laser output power P3 = 72 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 58000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 16 volts, laser output power P4 = 84 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s.

[0067] Embodiment 11 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0068] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 84 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 78000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 58000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14 volts, laser output power P3 = 72 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 58000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 16 volts, laser output power P4 = 84 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 75000 mm / s.

[0069] Example 12 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0070] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 84 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 80000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 72 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 58000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14 volts, laser output power P3 = 72 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 58000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 16 volts, laser output power P4 = 84 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 77000 mm / s.

[0071] Embodiment 13 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0072] (2) If Figure 2 As shown, along the width direction of the crystalline silicon solar cell prepared with metal grid lines (along the direction perpendicular to the fine grid lines), the sintering area of ​​the crystalline silicon solar cell is divided into the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) in turn; the size of the first sintering area (S1), the second sintering area (S2), the third sintering area (S3), and the fourth sintering area (S4) are all 210mm x 52.5mm; (3) using laser to irradiate the metal grid lines on each of the to-be-sintered areas, and applying a bias voltage to the metal grid lines on each of the to-be-sintered areas to sinter the metal grid lines; The process parameters of the first sintering zone are: bias voltage V1 = 16 volts, laser output power P1 = 55 watts, laser frequency F1 = 55 kHz, laser scanning speed W1 = 80000 mm / s; The process parameters of the second sintering zone are: bias voltage V2 = 14 volts, laser output power P2 = 50 watts, laser frequency F2 = 55 kHz, laser scanning speed W2 = 58000 mm / s; The process parameters of the third sintering zone are: bias voltage V3 = 14 volts, laser output power P3 = 50 watts, laser frequency F3 = 55 kHz, laser scanning speed W3 = 58000 mm / s; The process parameters of the fourth sintering zone are: bias voltage V4 = 16 volts, laser output power P4 = 55 watts, laser frequency F4 = 55 kHz, laser scanning speed W4 = 77000 mm / s.

[0073] Comparative Example 1 A laser-assisted sintering method, comprising: (1) Select a TOPCon cell with a size of 210mm x 210mm, use silver paste as the raw material for the metal grid line, and use screen printing to print the silver paste on the front of the TOPCon cell to obtain a crystalline silicon solar cell with a metal grid line. The fine grid lines of the TOPCon cell are printed along the length of the cell, arranged in the form of parallel lines, and fill the entire front of the cell; therefore, the entire front of the TOPCon cell is the area to be sintered.

[0074] (2) If Figure 1 As shown, there is no need to partition the metal grid lines of the crystalline silicon solar cell for sintering. The bias voltage loaded in the entire sintering area of ​​the crystalline silicon solar cell is the same value, and the output power of the laser used in the entire sintering area is also the same value. (3) Using laser to irradiate the metal grid lines of the crystalline silicon solar cell, and loading a bias voltage on the metal grid lines to sinter the metal grid lines; the sintering process parameters are: bias voltage V'=16 volts, laser output power P'=84 watts, laser frequency F'=55 kHz, laser scanning speed W'=75000 mm / s.

[0075] Photoelectric tests were performed on the crystalline silicon solar cells prepared in the above embodiments and comparative examples. The test results are shown in Table 1 below.

[0076] Table 1 (Using Comparative Example 1 as a reference, the efficiency improvement data of laser sintering of Examples 1-12 were obtained.)

[0077] In the above table, Eta refers to the photoelectric conversion efficiency of the battery, Uoc refers to the open circuit voltage of the solar cell, Isc refers to the short-circuit current, FF refers to the fill factor, Rs refers to the series resistance of the battery, Rsh refers to the parallel resistance, and Irev2 refers to the reverse saturation current. Taking Example 1 as an example, Eta (%) in the above table = 0.121, which specifically means that the photoelectric conversion efficiency of the battery in Example 1 is increased by 0.121% relative to Comparative Example 1; FF (%) = 0.57, which specifically means that the fill factor of the battery in Example 1 is increased by 0.57% relative to Comparative Example 1; Rsh (Ω) = -50.2, which specifically means that the parallel resistance of the battery in Example 1 is reduced by 50.2Ω relative to Comparative Example 1; Isc (A) = 0.05, which specifically means that the short-circuit current of the battery in Example 1 is increased by 0.05A relative to Comparative Example 1.

[0078] Referring to the detection data of the above embodiments 1-12, it can be known that controlling the bias voltage and laser output power of each sintering area can effectively improve the sintering effect of the metal grid line, so that the crystalline silicon solar cell forms a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0079] Referring to the test data of the above-mentioned embodiments 1-3, it can be known that controlling the value of N, that is, controlling the proportion of the area of ​​each to-be-sintered area, can further improve the sintering effect of the metal grid line, so that the crystalline silicon solar cell forms a better ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell. When N is equal to 4 or 6, the photoelectric conversion efficiency of the crystalline silicon solar cell is higher.

[0080] Referring to the detection data of the above-mentioned embodiments 1, 5 and 6, it can be known that the reasonable control of the bias voltage of each sintering area can further improve the sintering effect of the metal grid line, so that the crystalline silicon solar cell forms a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0081] Referring to the detection data of the above-mentioned Examples 1, 7, 8 and 9, it can be known that reasonable control of the output power of the laser in each area to be sintered can further improve the sintering effect of the metal grid line, so that the crystalline silicon solar cell forms a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0082] With reference to the detection data of the above-mentioned Examples 1, 10, 11, 12 and 13, it can be known that the sintering effect of the metal grid line can be further improved by reasonably controlling the output power of the laser and the laser scanning speed of each sintering area, so that the crystalline silicon solar cell can form a good ohmic contact, thereby improving the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0083] To summarize, the present application divides the crystalline silicon solar cell prepared with metal grid lines into multiple sintering areas, controls the bias voltage and laser output power of each sintering area, can effectively improve the sintering effect of the metal grid lines, enables the crystalline silicon solar cell to form a good ohmic contact, and thus improves the photoelectric conversion efficiency of the crystalline silicon solar cell.

[0084] The present application can provide a crystalline silicon solar cell (not shown), wherein the metal grid lines of the crystalline silicon solar cell are prepared by the above-mentioned laser-assisted sintering method.

[0085] The embodiment of the present application can provide a photovoltaic module, including the crystalline silicon solar cell in any of the above embodiments. The photovoltaic module also has the advantages of the above crystalline silicon solar cell, which will not be repeated here.

[0086] It should be noted that 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. are only for the convenience of describing the present application and simplifying the description, and do 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. The orientation words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here are interpreted accordingly.

[0087] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0088] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0089] It should also be noted that the above are only preferred embodiments of the present application, and the patent protection scope of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A laser-assisted sintering method, characterized in that: include: Dividing the sintering area of ​​the crystalline silicon solar cell into N equal parts along a direction perpendicular to the fine grid lines, to obtain the first to Nth sintering areas arranged in sequence, wherein N is a positive integer ≥ 4; metal grid lines are prepared on the sintering areas, and the metal grid lines include the fine grid lines; Using laser to irradiate the metal grid lines on each area to be sintered, and applying bias voltage to the metal grid lines in each area to be sintered, so as to sinter the metal grid lines; Wherein, the bias voltage of the first zone to be sintered is greater than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the first zone to be sintered is greater than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; The bias voltage of the Nth zone to be sintered is greater than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the Nth zone to be sintered is greater than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered.

2. The laser-assisted sintering method according to claim 1, characterized in that: The N is equal to 4, 6 or 8.

3. The laser-assisted sintering method according to claim 1, characterized in that: The bias voltage of the first zone to be sintered is 2-4V higher than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the first zone to be sintered is 10-20% higher than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; and / or The bias voltage of the Nth zone to be sintered is 2~4V higher than the bias voltage of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered; the laser output power of the Nth zone to be sintered is 10~20% higher than the laser output power of any zone to be sintered between the first zone to be sintered and the Nth zone to be sintered.

4. The laser-assisted sintering method according to claim 1, characterized in that: The bias voltage on the first sintering area is 16-22V; and / or The bias voltage on any area to be sintered between the first area to be sintered and the Nth area to be sintered is 14-18V; and / or The bias voltage on the Nth area to be sintered is 16-22V.

5. The laser-assisted sintering method according to claim 1, characterized in that: The laser output power of the first sintering zone is 84.0-93.5W, and the laser frequency is 45-55kHz; and / or On any area to be sintered between the first area to be sintered and the Nth area to be sintered, the output power of the laser is 72.00-80.75 W, and the frequency of the laser is 45-55 kHz; and / or The laser output power of the Nth area to be sintered is 84.0-93.5 W, and the frequency of the laser is 45-55 kHz.

6. The laser-assisted sintering method according to claim 5, characterized in that: The laser output power of the first sintering zone is 84-87W, and the laser frequency is 45-55kHz; and / or On any area to be sintered between the first area to be sintered and the Nth area to be sintered, the output power of the laser is 72.00-80.75 W, and the frequency of the laser is 45-55 kHz; and / or The laser output power of the Nth area to be sintered is 90-93W, and the frequency of the laser is 45-55kHz.

7. The laser-assisted sintering method according to any one of claims 1 to 6, characterized in that: On the first sintering area, the scanning speed of the laser is 75000-80000 mm / s; On any sintering area between the first sintering area and the Nth sintering area, the scanning speed of the laser is 58000-60000 mm / s; On the Nth area to be sintered, the scanning speed of the laser is 75000-80000 mm / s.

8. The laser-assisted sintering method according to claim 7, characterized in that: On the first sintering area, the scanning speed of the laser is 78000-80000 mm / s; On any sintering area between the first sintering area and the Nth sintering area, the scanning speed of the laser is 58000-60000 mm / s; On the Nth area to be sintered, the scanning speed of the laser is 75000-77000 mm / s.

9. A crystalline silicon solar cell, characterized in that: The metal grid lines of the crystalline silicon solar cell are prepared by the laser-assisted sintering method as claimed in any one of claims 1 to 8.

10. A photovoltaic module, characterized in that: Comprising the crystalline silicon solar cell as claimed in claim 9.

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