Solar cell sintering apparatus and sintering method of solar cell

Abstract

The invention belongs to the field of solar cells. The invention provides a solar cell sintering apparatus and a sintering method of a solar cell. The apparatus comprises: a furnace chamber; the transmission device is located in the furnace chamber, and the transmission device is used for transmitting solar cells; the pre-sintering unit comprises infrared lamp tubes, and the infrared lamp tubes are distributed on the two opposite sides of the conveying device; the laser sintering unit is located at the downstream of the pre-sintering unit in the transmission direction of the solar cells; and the image positioning system is used for acquiring the position of the solar cell. According to the solar cell sintering equipment provided by the embodiment of the invention, the energy consumption in a solar cell piece sintering process can be saved, the occupied area (the area required by the equipment) is reduced, and the cost is reduced.

Description

Technical Field

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

[0002] Using metal electrodes as a new energy technology for collecting photocurrent in solar cells is gaining popularity. Existing metal electrodes are basically formed by screen printing metal wet slurry to form wet metal electrodes, and then pass through a traditional chain sintering furnace through low-temperature drying, medium-temperature pre-sintering, high-temperature peak sintering, cooling and other processes to form metal electrodes with good ohmic contact.

[0003] In the whole process of curing and sintering wet metal electrodes in the traditional chain-type integrated sintering furnace, the cells are also exposed to the heat from the lamp tubes throughout the process, and the important link to achieve silver-silicon contact is mainly achieved by heat treatment of the solar cells in the isolated infrared (IR) lamp power supply chamber. This not only makes the internal defects of the cells infinitely magnified under high temperature conditions, but also in the high-temperature peak sintering step, the actual heat generated by the infrared lamp in the infrared (IR) lamp power supply chamber cannot reach the set sintering temperature to a certain extent, so that the sintering process cannot proceed as scheduled. In addition, the chain-type sintering furnace lamp tubes need to be continuously heated to meet the sintering process requirements, and the power consumption is relatively high.

[0004] 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

[0005] The embodiments of the present application provide a solar cell sintering device and a solar cell sintering method to solve or alleviate the above-mentioned technical problems such as the heat failing to reach the sintering temperature and high energy consumption.

[0006] In a first aspect of the embodiments of the present application, a solar cell sintering device is provided. The device comprises: a furnace cavity; a transmission device, the transmission device is located in the furnace cavity, and the transmission device is used to transmit solar cells; a pre-sintering unit, the pre-sintering unit comprises infrared lamps, and the infrared lamps are distributed on opposite sides of the transmission device; a laser sintering unit, in the direction of transmission of the solar cell, the laser sintering unit is located downstream of the pre-sintering unit; an image positioning system, the image positioning system is used to collect the position of the solar cell.

[0007] The solar cell sintering equipment of the embodiment of the present application has a pre-sintering unit and a laser sintering unit. When the transmission device transports the solar cell from the pre-sintering unit to the laser sintering unit, the laser sintering unit heats the solar cell by laser radiation, so that the solar cell can be quickly heated to the peak temperature (such as the laser sintering temperature) by the high energy density of the laser, while the temperature of the surrounding air is still low, thereby saving energy consumption, and reducing the floor space required for the high-temperature peak heating zone (the area required for the equipment) and reducing costs.

[0008] According to an embodiment of the present application, the laser sintering unit includes a laser and a laser adjustment mechanism; the laser adjustment mechanism is connected to the image positioning system and adjusts the position of the laser according to the image provided by the image positioning system.

[0009] According to an embodiment of the present application, when the image positioning system performs positioning, positioning is achieved by grabbing the mark points of the solar cell.

[0010] According to an embodiment of the present application, the solar cell sintering equipment further includes: a cooling unit, wherein the cooling unit is disposed on a side of the laser sintering unit away from the pre-sintering unit.

[0011] The second aspect of the embodiment of the present application provides a method for sintering a solar cell. The sintering of the solar cell is carried out in the solar cell sintering equipment described in the first aspect, and includes the following steps: providing a solar cell, wherein the solar cell has a wet metal electrode; performing pre-sintering and laser sintering on the solar cell in sequence to obtain a solar cell, wherein the pre-sintering is performed using an infrared lamp, and when the temperature of the solar cell itself reaches a threshold temperature, applying a laser to perform the laser sintering.

[0012] The sintering method of the embodiment of the present application first pre-sinters the solar cell to remove the resin inside the solar cell and melt the solid glass; then laser sinter the solar cell. During the laser sintering process, when the solar cell reaches the threshold temperature, the laser is turned on to irradiate the solar cell and heat the solar cell to the peak temperature (such as the sintering temperature). The higher temperature can melt the glass and burn through the functional layer (such as the anti-reflection layer silicon nitride film), so that the metal contacts the silicon surface of the cell to form a good ohmic contact. If the laser is applied too early (lower than the threshold temperature), at this time, because the temperature has not reached the threshold temperature, the glass powder in the slurry (such as silver slurry) used to prepare the metal grid line has not yet begun to melt. Therefore, before the temperature reaches the threshold temperature, even if the laser is applied, it will not accelerate the metal ions (such as silver particles) in the slurry to flow from the glass system to the surface of the solar cell, but will cause energy waste; and if the laser is applied too late (greater than the threshold temperature), the pre-sintering unit needs to apply more energy to reach the required temperature, which will cause energy waste and cost increase of the pre-sintering unit. In addition, using laser sintering instead of traditional chain lamp sintering can effectively avoid local defects of the battery caused by different sintering degrees of different parts of the battery cell due to uneven temperature in the furnace chamber, and the uniformly emitted surface scanning laser can achieve sufficient silver-silicon contact and greatly reduce the cloud defect rate, as well as improve the photoelectric performance of solar cells.

[0013] According to an embodiment of the present application, the pre-sintering includes: performing a low-temperature drying treatment on the solar cell; and continuing to heat the dried solar cell to perform medium-temperature sintering.

[0014] According to an embodiment of the present application, the temperature of the low-temperature drying treatment is 100-200° C., and the time is 8-12 seconds.

[0015] According to an embodiment of the present application, the medium-temperature sintering is performed at a temperature of 210-600° C. and a time of 10-15 seconds.

[0016] According to an embodiment of the present application, the temperature of the laser sintering is 610-900°C.

[0017] According to an embodiment of the present application, the laser used in the laser sintering process is red light with a wavelength of 700-900nm.

[0018] According to an embodiment of the present application, the threshold temperature is 450-600°C.

[0019] According to an embodiment of the present application, when the temperature of the medium-temperature sintering in the pre-sintering process is lower than the threshold temperature, it further includes: continuing to heat the pre-sintering product so that the temperature of the solar cell after the medium-temperature sintering reaches the threshold temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] Figure 1 is a schematic structural diagram of a solar cell sintering device provided in an embodiment of the present application; Figure 2 It is a structural schematic diagram of another solar cell sintering device provided in an embodiment of the present application; Figure 3 It is a schematic diagram of the solar cell structure provided in an embodiment of the present application.

[0022] Description of reference numerals: 1: Transmission device; 2: Pre-sintering unit; 21: Infrared lamp; 3: Laser sintering unit; 31: Laser; 32: Laser adjustment mechanism; 4: Cooling unit; 5: Image positioning system; 6: Substrate; 7: Boron-doped layer; 8: Passivation layer; 9: Anti-reflection layer; 10: Tunneling oxide layer; 11: Phosphorus-doped layer; 12: Metal silver wet electrode. DETAILED DESCRIPTION

[0023] 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.

[0024] 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 application, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. When the second element, component, region, layer or part is discussed, it does not indicate that the present application necessarily has the first element, component, region, layer or part.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] Contact sintering is a mature process in the production of industrial silicon solar cells, that is, the solar cell is transported by a sintering conveyor belt, and after low-temperature drying, medium-temperature pre-sintering, high-temperature peak sintering, cooling and other stages, the metal electrode forms a good ohmic contact with the silicon substrate, thereby improving the cell conversion efficiency by improving the fill factor (FF). At present, the traditional firing process is mainly to heat the solar cell in an isolated infrared (IR) lamp-powered chamber. The working principle of the chamber is to increase the temperature of the surrounding air by heating the infrared lamp and to make the lamp radiation uniform through the reflection of the sintering chamber to achieve high-temperature sintering of the solar cell. However, the resulting convection and reflected radiation heating will lead to a large amount of energy waste, and thus the wafer is not effectively heated. That is, the energy required for heating is in the heating chamber, and the energy rises in the form of radiation, and is ultimately not absorbed by the solar cell. Low-power industrial IR lamps and the above energy waste will lead to low power density on the solar cell, and a longer chamber with a larger footprint is required to heat the solar cell to the necessary temperature of about 700-900°C to achieve silver-silicon contact. This results in energy loss and increased costs.

[0029] According to the first aspect of the embodiment of the present application, a solar cell sintering device is provided. Figure 1 The sintering equipment includes: a furnace chamber; a transmission device 1, which is located in the furnace chamber and is used to transmit solar cells; a pre-sintering unit 2, which includes infrared lamps 21, and the infrared lamps 21 are distributed on opposite sides of the transmission device 1; a laser sintering unit 3, which is located downstream of the pre-sintering unit 2 in the direction of transmission of the solar cells; and an image positioning system 5, which is used to collect the position of the solar cells.

[0030] The solar cell sintering equipment of the embodiment of the present application has a pre-sintering unit and a laser sintering unit. When the transmission device transports the solar cell from the pre-sintering unit to the laser sintering unit, the laser sintering unit heats the solar cell by laser radiation, so that the solar cell can be quickly heated to the peak temperature (such as the laser sintering temperature) by the high energy density of the laser, while the temperature of the surrounding air is still low, thereby saving energy consumption, and reducing the floor space required for the high-temperature peak heating zone (the area required for the equipment) and reducing costs.

[0031] In some embodiments, reference Figure 2 The laser sintering unit includes a laser 31 and a laser adjustment mechanism 32; the laser adjustment mechanism 32 is connected to the image positioning system 5, and adjusts the position of the laser according to the image provided by the image positioning system 5. When the solar cell is transmitted to the laser sintering unit, the image positioning system locates the position of the solar cell and sends the positioning information to the laser adjustment mechanism, and the laser adjustment mechanism fine-tunes the position of the laser to align the laser with the grid line of the solar cell.

[0032] In some embodiments, the image positioning system performs positioning by grabbing the mark points of the solar cell. The solar cell is transported from the pre-sintering unit to the laser sintering unit by a transmission device. The camera (image positioning system) in the laser sintering unit is used to grab the mark points on the outer edge and surface of the solar cell for positioning and edge grabbing, and at the same time sends the positioning information to the laser adjustment mechanism. The laser adjustment mechanism fine-tunes the position of the laser so that the laser is aligned with the grid line of the solar cell to perform laser scanning to achieve high-temperature sintering.

[0033] In some embodiments, the laser sintering unit includes two laser emitters. When irradiating the solar cell, the light beams of the two laser emitters overlap and point to the solar cell on the transmission device.

[0034] In some embodiments, reference Figure 1 and 2 The solar cell sintering equipment further includes: a cooling unit 4. The cooling unit is arranged on a side of the laser sintering unit away from the pre-sintering unit. No heating lamp is arranged in the cooling unit, so that the solar cell after laser sintering is air-cooled.

[0035] In some embodiments, the transmission device includes a transmission drive and a chain belt.

[0036] It can be understood that the pre-sintering unit, the laser sintering unit and the cooling unit are all located in the furnace cavity, and the three are connected by a transmission device to sinter and cool the solar cell.

[0037] The existing laser sintering is performed directly after the wet metal electrode is printed. It is a rapid heating process, which means that the wet metal electrode does not have effective process time for low-temperature drying and medium-temperature pre-sintering, thereby effectively removing the organic components and resin components in the metal slurry. Even the glass powder cannot be effectively melted, affecting the integrity of the sintering process.

[0038] Accordingly, the second aspect of the embodiment of the present application provides a sintering method for a solar cell. The sintering process is carried out in the sintering equipment provided in the first aspect. The sintering method comprises the following steps: (1) providing a solar cell, wherein the solar cell has a wet metal electrode; (2) sequentially performing pre-sintering and laser sintering on the solar cell to obtain a solar cell, wherein the pre-sintering is performed using an infrared lamp tube, and when the temperature of the solar cell itself reaches a threshold temperature, a laser is applied to perform laser sintering.

[0039] The sintering method of the embodiment of the present application first pre-sinters the solar cell to remove the resin inside the solar cell and melt the solid glass; then laser sinter the solar cell. During the laser sintering process, when the solar cell reaches the threshold temperature, the laser is turned on to irradiate the solar cell and heat the solar cell to the peak temperature (such as the sintering temperature). The higher temperature can melt the glass and burn through the functional layer (such as the anti-reflection layer silicon nitride film), so that the metal contacts the silicon surface of the cell to form a good ohmic contact. If the laser is applied too early (lower than the threshold temperature), at this time, because the temperature has not reached the threshold temperature, the glass powder in the slurry (such as silver slurry) used to prepare the metal grid line has not yet begun to melt. Therefore, before the temperature reaches the threshold temperature, even if the laser is applied, it will not accelerate the metal ions (such as silver particles) in the slurry to flow from the glass system to the surface of the solar cell, but will cause energy waste; and if the laser is applied too late (greater than the threshold temperature), the pre-sintering unit needs to apply more energy to reach the required temperature, which will cause energy waste and cost increase of the pre-sintering unit. In addition, using laser sintering instead of traditional chain lamp sintering can effectively avoid local defects of the battery caused by different sintering degrees of different parts of the battery cell due to uneven temperature in the furnace chamber, and the uniformly emitted surface scanning laser can achieve sufficient silver-silicon contact and greatly reduce the cloud defect rate, as well as improve the photoelectric performance of solar cells.

[0040] According to an embodiment of the present application, step (1) provides a solar cell having a wet metal electrode.

[0041] In some embodiments, the solar cell is a solar cell having wet metal electrodes.

[0042] In some embodiments, the wet metal electrodes may be on opposite sides of the cell (such as in a heterojunction solar cell) or may be present on only one side (in a back contact solar cell).

[0043] In some embodiments, the wet metal electrode includes metal silver paste, silver aluminum paste, etc.

[0044] According to an embodiment of the present application, step (2) sequentially pre-sinters and laser sinters the solar cell to obtain a solar cell.

[0045] In some embodiments, pre-sintering includes: low-temperature drying of the solar cell; and further heating of the dried solar cell to perform medium-temperature sintering. In this process, low-temperature drying can remove organic components in the solar cell; and the subsequent pre-sintering can remove the resin and melt the solid glass, which is conducive to the subsequent laser sintering.

[0046] In some embodiments, the temperature of the low temperature drying process is 100-200° C., such as 100° C., 150° C., 200° C., etc.

[0047] In some embodiments, the low-temperature drying treatment time is 8-12 seconds, such as 8 seconds, 10 seconds, 12 seconds, etc.

[0048] In some embodiments, the medium temperature sintering temperature is 210-600°C, such as 210°C, 300°C, 400°C, 600°C, etc.

[0049] In some embodiments, the time is 10-15s, such as 10s, 12s, 15s, etc.

[0050] In some embodiments, laser sintering can generate a higher temperature that can melt the glass and burn through the functional layer (such as the anti-reflection layer silicon nitride film) to make the metal contact with the cell silicon surface to form a good ohmic contact.

[0051] In some embodiments, the temperature of laser sintering is 610-900° C., for example, 610° C., 700° C., 800° C., 900° C., etc.

[0052] In some embodiments, the laser used in the laser sintering process is red light with a wavelength of 700-900 nm.

[0053] In some embodiments, when the temperature of the medium-temperature sintering in the pre-sintering process is lower than the threshold temperature, the method further includes: continuing to heat the pre-sintering product so that the temperature of the solar cell after the medium-temperature sintering reaches the threshold temperature. In this way, the glass can be melted, which is beneficial to accelerate the flow of silver ions from the glass system to the surface of the solar cell.

[0054] In some embodiments, the threshold temperature is 450-600°C.

[0055] In other embodiments, when the medium-temperature sintering temperature in the pre-sintering process is the same as the threshold temperature, the solar cell may be directly laser sintered.

[0056] In some embodiments, the method further includes cooling the laser sintered product, wherein the cooling process is natural air cooling.

[0057] Hereinafter, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. It should be noted that these exemplary embodiments can be implemented in many different forms and should not be construed as being limited to the embodiments described herein.

[0058] The solar cell sintering equipment in the solar cell sintering process of the following embodiments refers to Figure 1 and Figure 2 During the sintering process, the solar cell is placed on the transmission device to perform pre-sintering and laser sintering on the solar cell in sequence. During the laser sintering process, the image positioning system is used to capture the mark point of the cell, and the result is transmitted to the laser adjustment mechanism, so that the laser adjustment mechanism can fine-tune the position of the laser, prompting the laser to align with the grid line of the solar cell, so as to perform laser scanning to achieve high-temperature sintering. During the sintering process, a temperature controller can be used to monitor the temperature. The solar cell sintering equipment of Comparative Example 1 does not have a laser sintering unit, and the solar cell sintering equipment of Comparative Example 2 does not have a pre-sintering unit.

[0059] The solar cells of the following embodiments and comparative examples are referenced to Figure 3 , the solar cell comprises a substrate 6, a boron-doped layer 7, a passivation layer 8, an anti-reflection layer 9, a tunneling oxide layer 10, a phosphorus-doped layer 11 and a metal silver wet electrode 12. The boron-doped layer is located on the first surface of the substrate, the passivation layer is located on the side of the boron-doped layer away from the substrate; the tunneling oxide layer is located on the second surface of the substrate, the phosphorus-doped layer is located on the side of the tunneling oxide layer away from the substrate, the side of the phosphorus-doped layer away from the tunneling oxide layer and the side of the passivation layer away from the boron-doped layer are both provided with an anti-reflection layer, and the metal electrode is in contact with the phosphorus-doped layer or the boron-doped layer. The thickness of the boron-doped layer and the phosphorus-doped layer is 120nm, the thickness of the passivation layer is 30nm, and the thickness of the anti-reflection layer is 40nm.

[0060] Example 1 S1: performing low-temperature drying treatment on the solar cell with wet metal electrodes, the temperature of the low-temperature drying treatment is 150° C., and the time is 10 seconds.

[0061] S2: The dried solar cell sheets are subjected to medium-temperature sintering, the medium-temperature sintering temperature is 600° C., the time is 12 seconds, and both low-temperature drying and medium-temperature sintering are performed using infrared lamps.

[0062] S3: laser sintering is performed on the solar cell after medium temperature sintering. During the laser sintering process, the laser condition is controlled to be red light with a wavelength of 808nm, and the laser sintering temperature is 800°C.

[0063] S4: Cooling the solar cell after laser sintering to obtain a solar cell.

[0064] Example 2 The solar cell sheet with the wet metal electrode is sintered in the manner of Example 1 to obtain a solar cell, except that in step S2: the temperature of the medium-temperature sintering is 450°C.

[0065] Examples 3 and 4 The solar cell sheet with the wet metal electrode is sintered in the manner of Example 1 to obtain a solar cell, except that in step S3: the laser sintering temperatures are 650° C. and 900° C. respectively.

[0066] Example 5 S1: The solar cell with wet metal electrodes is subjected to low temperature drying, wherein the temperature during the low temperature drying is 150° C. and the time is 10 seconds.

[0067] S2: The dried solar cell sheets are subjected to medium-temperature sintering, the medium-temperature sintering temperature is 300° C., the time is 12 seconds, and both low-temperature drying and medium-temperature sintering are performed using infrared lamps.

[0068] The solar cell sintered at medium temperature is then heated up to a temperature of 600°C. S3: performing laser sintering on the heated solar cell. During the laser sintering process, the laser condition is controlled to be red light with a wavelength of 808 nm, and the laser sintering temperature is 800°C.

[0069] S4: Cooling the solar cell after laser sintering to obtain a solar cell.

[0070] Comparative Example 1 S1: drying the solar cell with wet metal electrodes at a temperature of 150° C. for 6 seconds.

[0071] S2: medium-temperature sintering is performed on the dried solar cell sheets, the medium-temperature sintering temperature is 400° C., and the time is 12 seconds.

[0072] S3: The solar cell pieces after medium temperature sintering are subjected to high temperature sintering, the temperature of high temperature sintering is 800°C, and the time is 6s; wherein, the drying process, medium temperature sintering and high temperature sintering are all carried out by infrared lamps.

[0073] S4: Cooling the heated solar cell to obtain a solar cell.

[0074] Comparative Example 2 S1: Laser sintering of a solar cell with a wet metal electrode. During the laser sintering process, the laser condition is controlled to be red light with a wavelength of 808 nm and the laser sintering temperature is 800°C.

[0075] S2: Cooling the solar cell after laser sintering to obtain a solar cell.

[0076] The photovoltaic performance and photoluminescence (PL) tests of the solar cells are carried out. The test results are shown in Table 1.

[0077] Photoelectric performance test: The test method uses a current-voltage (IV) measurement system (FCT750, Sinton, America) under standard test conditions (AM 1.5, 100 mW / cm 2 , 25°C) to determine the electrical parameters of the solar cell.

[0078] Photoluminescence (PL) test: The photoluminescence (PL) of solar cells was obtained by a BT imaging LIS-R3 system (LIS-R3, BTimaging, Australia).

[0079] Electroluminescence (EL) test: CCD is used to collect carrier light emission and then converted into an image. The more carrier recombination, the brighter the corresponding EL image, and vice versa. The cell yield is monitored based on the EL brightness.

[0080] Daily electricity cost: 1) The electricity cost of the infrared lamp high temperature sintering stage = the power supply required for each lamp to heat up individually * 24 lamps * 24 hours * electricity unit price; 2) Electricity cost of laser sintering = (electricity used for laser scanning + camera tracking) * electricity price Table 1

[0081] It can be seen from Table 1 above that the battery performance of Examples 1-5 is better than that of Comparative Examples 1-2, and the battery preparation cost of Examples 1-5 is lower than that of Comparative Examples 1-2. Compared with the conventional infrared lamp sintering process, the laser co-firing process proposed in the present application can form a better ohmic contact between the gate line and the battery silicon to improve the battery filling, so that the solar cell has better photoelectric performance. At the same time, the pre-sintering and laser co-firing process enables the battery to obtain a more uniform sintering, and the laser energy can be accurately controlled to achieve the mutual diffusion of silver paste and silicon, thereby reducing the cloudiness. According to the photoluminescence PL brightness value, it can be seen that the pre-sintering and laser co-firing process greatly reduces the battery defects of the battery. In addition, the electricity cost is also lower than that of conventional infrared sintering, and the actual floor space is also greatly reduced.

[0082] 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.

[0083] It should also be noted that the "some embodiments", "other embodiments", "embodiments", 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. Furthermore, when a specific feature, structure or characteristic is described 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.

[0084] 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.

[0085] 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 solar cell sintering device, characterized in that: include: Furnace cavity; A transmission device, the transmission device is located in the furnace cavity, and the transmission device is used to transmit solar cells; A pre-sintering unit, the pre-sintering unit comprising infrared lamps, the infrared lamps being distributed on opposite sides of the transmission device; A laser sintering unit, which is located downstream of the pre-sintering unit in the direction of transmission of the solar cell sheet; An image positioning system is used to collect the position of the solar cell.

2. The solar cell sintering equipment according to claim 1, characterized in that: The laser sintering unit includes a laser and a laser adjustment mechanism; the laser adjustment mechanism is connected to the image positioning system and adjusts the position of the laser according to the image provided by the image positioning system.

3. The solar cell sintering equipment according to claim 2, characterized in that: When the image positioning system performs positioning, positioning is achieved by grabbing the mark points of the solar cell sheet.

4. The solar cell sintering equipment according to claim 1, characterized in that: Also includes: Cooling unit, The cooling unit is disposed on a side of the laser sintering unit away from the pre-sintering unit.

5. A sintering method for a solar cell, characterized in that: The sintering of the solar cell is carried out in the solar cell sintering equipment according to any one of claims 1 to 4, comprising the following steps: Providing a solar cell having a wet metal electrode; The solar cell is pre-sintered and laser sintered in sequence to obtain a solar cell. The pre-sintering is performed by using an infrared lamp, and when the temperature of the solar cell itself reaches a threshold temperature, laser is applied to perform the laser sintering.

6. The sintering method according to claim 5, characterized in that: The pre-sintering comprises: Performing low-temperature drying treatment on the solar cell sheet; The solar cell sheet that has undergone the drying treatment is further heated to perform medium-temperature sintering.

7. The sintering method according to claim 6, characterized in that: The temperature of the low-temperature drying treatment is 100-200°C and the time is 8-12S; And / or, the medium-temperature sintering is performed at a temperature of 210-600° C. and a time of 10-15 seconds.

8. The sintering method according to claim 5, characterized in that: The laser sintering temperature is 610-900°C; And / or, the laser used in the laser sintering process is red light with a wavelength of 700-900nm.

9. The sintering method according to claim 6, characterized in that: The threshold temperature is 450-600°C.

10. The sintering method according to claim 9, characterized in that: When the temperature of the medium-temperature sintering in the pre-sintering process is lower than the threshold temperature, the method further comprises: The pre-sintered product is continuously heated up so that the temperature of the solar cell sheet sintered at the medium temperature reaches a threshold temperature.

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