A post-processing device for HJT solar cells

Abstract

A post-processing device for HJT solar cells, belonging to the photovoltaic field, includes a light injection system, an electrical injection system, and a support platform. The support platform holds the solar cells to be processed, and the light injection system injects light into the cells. The electrical injection system, positioned between the light source and the support platform, includes a frame-structured electrical injection carrier and a metal probe fixed to the carrier. The light source can penetrate gaps within the frame of the electrical injection carrier to illuminate the solar cells, and the metal probe performs electrical injection processing on the cells. This device enables combined light and electrical injection post-processing of the solar cells, improving production efficiency and optimizing economics.

Description

Technical Field

[0001] This utility model belongs to the field of photovoltaics, specifically relating to a post-processing device for HJT solar cells. Background Technology

[0002] Crystalline silicon heterojunction (HJT) solar cells possess advantages such as high photoelectric conversion efficiency, low temperature coefficient, high bifacial efficiency, and low-temperature manufacturing process with few steps, making them highly promising for applications. During HJT solar cell manufacturing, post-processing is required to promote a transformation of the material microstructure towards a direction conducive to defect passivation, thereby further improving the conversion efficiency of HJT solar cells. Currently, post-processing mainly includes photo-injection and electro-injection processes; however, photo-injection consumes high energy, and electro-injection is time-consuming, hindering further improvements in HJT cell production efficiency. Therefore, providing a post-processing device to improve the efficiency of HJT solar cell production is of positive significance for increasing production efficiency and reducing production costs. Utility Model Content

[0003] The purpose of this invention is to provide a post-processing device for HJT solar cells to improve the efficiency of HJT cell post-processing.

[0004] According to one embodiment of the present invention, a post-processing device for HJT solar cells is provided, comprising a light injection system, an electrical injection system, and a support stage, wherein...

[0005] The support platform is used to support the battery cells to be processed;

[0006] The light injection system includes a light source, which is positioned toward the support stage to provide light injection to the solar cell to be processed;

[0007] The electro-injection system includes an electro-injection carrier and metal probes. The electro-injection carrier is configured as a frame structure and is disposed between the support stage and the light source to allow light emitted from the light source to pass through the electro-injection carrier and illuminate the solar cell. A plurality of metal probes are disposed on the side of the electro-injection carrier facing the support stage and arranged in an array to provide electro-injection to the solar cell.

[0008] This device can apply a combined post-processing of light injection and electrical injection to the solar cells to be processed, effectively reducing the energy consumption of light injection, reducing the light injection intensity, shortening the process time, improving production efficiency, and extending the service life of the equipment.

[0009] Furthermore, in some embodiments, the support platform is provided with a heating resistance wire.

[0010] Heating resistance wires are used to heat the battery cells during post-processing.

[0011] Furthermore, in some embodiments, the light source includes multiple monochromatic or multicolor LED beads, and the emission spectrum wavelength of the LED beads is 450nm-950nm.

[0012] Furthermore, in some embodiments, the illuminance of the LED light source is 5 kW / m². 2 -30kW / m 2 .

[0013] Furthermore, in some embodiments, a cooling device is provided on the side of the LED light source facing away from the support platform.

[0014] Furthermore, in some embodiments, the cooling device is configured as a water-cooling device, and includes a water-cooling plate disposed on the surface of the LED light source and cooling pipes passing through the water-cooling plate, wherein the cooling pipes contain flowing coolant.

[0015] Furthermore, in some embodiments, a plurality of the metal probes are arranged in a straight line to form a probe array, the bases of the metal probes in the probe array are connected as a whole, and the two ends of the probe array are fixedly connected to the electro-injection carrier.

[0016] Furthermore, in some embodiments, multiple probe arrays are arranged in parallel on the electro-injection carrier, and the surface of the electro-injection carrier provides multiple sets of mounting positions. When the probe arrays are mounted in different mounting positions, they have different relative positional relationships with the support platform.

[0017] Furthermore, in some embodiments, the upper surface of the support platform is configured as a conductive structure.

[0018] Furthermore, in some embodiments, the electro-injection system further includes a lifting device that drives the electro-injection carrier to approach or move away from the support platform, so that the metal probe contacts or separates from the battery cell to be processed. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the HJT solar cell post-processing device in one embodiment;

[0020] Figure 2 This is a schematic diagram of the cooling device structure in one embodiment;

[0021] Figure 3 This is a schematic diagram of the electrical injection system structure in one embodiment;

[0022] Figure 4 This is a schematic diagram of the probe array structure in one embodiment.

[0023] Meaning of reference numerals in the attached diagram: 100-Water cooling plate; 101-Cooling water inlet; 102-Cooling water outlet; 103-Cooling pipe; 200-Light source; 201-LED lamp bead; 300-Electrical injection carrier; 301-Metal gasket; 302-Insulating gasket; 303-Probe array; 304-Insulating screw; 305-Insulating nut; 306-Metal probe; 400-DC constant current power supply; 401-Wire; 500-Support platform; 501-Heating resistance wire; 600-Solar cell; 700-Air cooling system.

[0024] The purpose of the above-described drawings is to provide a detailed description of the present invention so that those skilled in the art can understand the technical concept of the present invention, and not to limit the present invention. For the sake of brevity, the above-described drawings only schematically depict the structures related to the technical features of the present invention, and do not strictly follow the actual scale to show the complete structure and all details. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0026] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment herein. The phrase appearing in various places in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive, independent, or alternative embodiments. Those skilled in the art will understand that the embodiments herein can be combined with other embodiments without causing structural conflicts.

[0027] In this description, unless otherwise explicitly specified and limited, the technical terms "installation," "connection," "joining," etc., should be interpreted broadly, for example, referring to movable connections, fixed connections, or integration. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0028] In this description, terms such as "upper," "lower," "left," "right," "lateral," "longitudinal," "height," "length," and "width," which indicate orientation or positional relationships, are intended to accurately describe the embodiments and simplify the description, rather than limiting the parts or structures involved to have a specific orientation, or to be installed or operated in a specific orientation, and should not be construed as limiting the embodiments in this document.

[0029] In this description, terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating relative importance or limiting the number, specific order, or primary / secondary relationship of the described technical features. In this description, "multiple" means at least two.

[0030] Crystalline silicon heterojunction (HJT) solar cells, also known as HIT, SHJ, HAC, etc., are currently receiving widespread attention due to their advantages such as high photoelectric conversion efficiency, low temperature coefficient, low-temperature manufacturing process throughout, fewer process steps, and high bifaciality.

[0031] Currently, the highest photoelectric conversion efficiency of HJT single-junction cells has reached 26.81%, and the average efficiency of mass-produced solar cells of this type has also exceeded 25.5%.

[0032] HJT solar cells primarily employ intrinsic hydrogenated amorphous silicon as the passivation layer, with heavily doped hydrogenated amorphous silicon / microcrystalline silicon thin films serving as the emitter and back surface field. These amorphous silicon / microcrystalline silicon films contain a significant proportion of hydrogen atoms, primarily existing through chemical or physical bonds with silicon, boron, and phosphorus atoms. Additionally, some hydrogen atoms exist in a free state. These different hydrogen atom configurations can influence the passivation and electrical performance of the HJT cell.

[0033] In the production and preparation process of this type of solar cell, CVD and PVD technologies are mainly used for thin film deposition. The entire thin film growth process requires the substrate to be heated to an appropriate temperature, which generally does not exceed 250°C. Since the bond energy of silicon-hydrogen bonds and some physical hydrogen bonds is very small, this process can easily cause changes in the configuration of hydrogen atoms, resulting in hydrogen atom overflow or recombination.

[0034] During the fabrication of HJT solar cells, especially in industrial production, capacity limitations prevent precise process control, inevitably resulting in defects in the deposited thin film. Hydrogen atoms can passivate and repair these defects. Therefore, after HJT solar cell fabrication, appropriate post-processing methods can be employed to promote the movement and recombination of hydrogen atoms in the film, guiding them towards defect passivation. This provides a new approach to further improve the conversion efficiency of HJT solar cells.

[0035] Currently, the main post-processing techniques include light injection and electrical injection. Light injection involves irradiating the HJT solar cells with light sources such as infrared lamps, near-infrared lasers, and LEDs. Simultaneously, the process temperature can reach 160-250℃, and the light intensity can reach up to 70kW / m². 2 -100kW / m 2The process time is generally 100s-300s, which can effectively improve the conversion efficiency of solar cells. In addition, electro-injection has also been attempted in HJT photovoltaic modules, using a direct current of approximately 1A-20A to improve conversion efficiency. To prevent damage to HJT modules, the electro-injection current is generally small, and the efficiency improvement time is longer.

[0036] However, the light intensity of the light source used in existing light injection equipment and methods is very high, reaching 70kW / m². 2 -100kW / m 2 This results in enormous energy consumption. Furthermore, the heat generated by the light source during such high-intensity operation is considerable, requiring a larger flow of cooling water to maintain the light source at a suitable operating temperature, ensuring safety and extending its lifespan. On the other hand, the high light intensity causes a dramatic rise in the temperature of the HJT battery during post-processing. Temperatures exceeding 250°C can damage the hydrogenated amorphous silicon film, leading to performance degradation. Therefore, a more powerful cooling system is needed to dissipate heat from the battery surface to achieve a process temperature of 180°C-220°C. Cooling methods typically include CDA cooling or air cooling, generating additional energy consumption. Moreover, regardless of whether photo-injection or electro-injection processes are used, the process time required to reach efficiency saturation is very long, typically 100-300 seconds, which is detrimental to improving production cycle time.

[0037] To address the aforementioned issues, embodiments of this invention provide an HJT solar cell post-processing device that can provide composite post-processing combining light injection and electrical injection for the solar cells, thereby improving post-processing efficiency while effectively reducing energy consumption and optimizing process economy.

[0038] The structure of the device is as follows Figure 1 As shown, it includes an optical injection system, an electrical injection system, and a support stage 500.

[0039] Among them, the support platform 500 is used to support the solar cells 600 to be processed.

[0040] The light injection system includes a light source 200, which is positioned toward the support stage 500 and is used to provide light injection to the solar cell 600.

[0041] Specifically, a plurality of LED beads 201 are arranged on the side of the light source 200 facing the support platform 500. These LED beads 201 are configured as monochromatic or multicolor beads. In a preferred embodiment, the emission spectrum wavelength range of the LED beads 201 is 450nm-950nm. In a preferred embodiment, the illuminance of the light source 200 is 5kW / m². 2 -30kW / m 2 The intensity of light can be adjusted by the electrical power fed into the light source.

[0042] In other embodiments, depending on the parameter design requirements of the light injection process, other types of light sources such as laser light sources or light irradiation of other wavelengths may also be used.

[0043] In a preferred embodiment, a cooling device is provided on the side of the light source 200 facing away from the support platform 500. For example... Figure 2 As shown, the cooling device includes a water cooling plate 100 and cooling pipes 103 passing through the water cooling plate 100. The cooling pipes 103 are configured as a reciprocating tortuous flow channel with a diameter of 5mm-20mm, and are distributed as evenly as possible within the water cooling plate 100. The cooling pipes 103 can be configured as independent components such as copper pipes, or they can be formed by machining into the substrate of the water cooling plate 100. The water cooling plate 100 is disposed on the surface of the light source 200. Cooling water flows in through the cooling water inlet 101 and flows out through the cooling water outlet 102, continuously providing cooling to the light source 200 during the light injection process. In other embodiments, the cooling water can be replaced by other coolants, such as cooling oil or solutions containing anti-corrosion components.

[0044] The electrical injection system includes an electrical injection carrier 300, and such as Figure 3 As shown, a metal probe 306 is fixedly connected to the electro-injection carrier 300. The electro-injection carrier 300 is positioned between the light injection system and the support stage 500, and is configured as a rectangular frame structure to allow light emitted from the light source 200 to pass through the space within the rectangular frame and provide light injection to the solar cell 600. The metal probes 306 are fixed in an array on the side of the electro-injection carrier facing the support stage 500 and are used to provide electro-injection to the solar cell 600. A DC constant current power supply 400 is connected to the metal probe 306 (which serves as the upper electrode) and the lower electrode via wires 401. In a preferred embodiment, the upper surface of the support stage 500 is configured as a conductive structure to serve as the lower electrode. When the metal probe 306 contacts the upper surface of the solar cell 600, a potential difference is generated between the upper and lower surfaces of the solar cell 600, thereby achieving electro-injection processing of the solar cell 600.

[0045] In different embodiments, the frame structure of the electrical injection carrier 300 can be configured as a single rectangular frame or as an array of multiple connected rectangular frames.

[0046] Combination Figure 3 and Figure 4 Multiple metal probes 306 are arranged in a straight line to form a probe row 303. The bases of the metal probes 306 in each probe row 303 are connected as a whole and fixedly connected to the frame of the electro-injection carrier 300 through both ends of the probe row 303.

[0047] Specifically, the electro-injection carrier 300 has multiple mounting holes on its side frames. These mounting holes have rounded chamfers. The probe arrays 303 overlap at both ends with the electro-injection carrier 300. Insulating screws 304 pass through the mounting holes from top to bottom, and insulating nuts 305 are used to tighten the screws 304 from below the electro-injection carrier 300 for secure installation. Above the mounting holes, insulating gaskets 302 and metal gaskets 301 are sequentially stacked. The metal gaskets 301 are elongated and extend along the frame direction of the electro-injection carrier 300. Each probe array 303 is connected via the metal gaskets 301 to ensure simultaneous conduction of current. The insulating gaskets 302 separate the metal gaskets 301 from the electro-injection carrier 300 to ensure insulation between the probe arrays 303 and the electro-injection carrier 300. In a preferred embodiment, multiple sets of mounting holes are provided to form multiple mounting positions. When the probe array 303 is installed in different mounting positions, it can have different relative positional relationships with the support platform 500, including different spacing between the probe arrays 303 and different projection positions on the support platform 500, thereby enabling adaptive adjustment according to different specifications of the solar cell 600. In some embodiments, the array of metal probes 306 includes different numbers of probe arrays 303. In some embodiments, the number of probe arrays is from 1 to 15.

[0048] In other embodiments, at least some of the metal probes 306 may also be directly and independently mounted on the bottom of the frame of the electro-injection carrier 300.

[0049] In a preferred embodiment, the electro-injection system further includes a lifting device, and the electro-injection carrier is fixedly connected to the lifting device so that it moves up and down with the lifting device, so that the metal probe 306 contacts or separates from the solar cell 600 to realize the switching on and off of the electro-injection circuit.

[0050] In a preferred embodiment, an air-cooling device 700 is also provided on one side of the HJT solar cell post-processing apparatus. The air-cooling device 700 is used to provide air cooling for the solar cell 600. A heating resistance wire 501 is provided inside the support platform 500 for heating the solar cell 600. The air-cooling device 700 and the heating resistance wire 501 can work alone or together to control the temperature of the solar cell 600 during the post-processing process within the range of 150°C-250°C.

[0051] In a preferred embodiment, the structure of the HJT solar cell post-processing device is as follows: Figures 1 to 4 As shown, the light source 200 uses a monochromatic LED with an emission wavelength of 660nm, and the light intensity provided by the light source 200 is 7kW / m². 2 The constant current power supply 400 output current is 30A, and the post-processing temperature of the solar cell 600 is set to 180℃, with a post-processing time of 1 min. The results are shown in Table 1.

[0052] In a comparative example, 7kW / m 2 Using 660nm monochromatic light as the light source, light injection was performed at 180℃ for 1 min. The results are shown in Table 1.

[0053]

[0054] Table 1 Comparison of Post-processing Results

[0055] As shown in Table 1, the improvement in cell efficiency (ΔEta) of the HJT solar cell in the embodiment is significantly higher than that in the comparative example. The HJT solar cell post-processing device provided in this embodiment can significantly improve the efficiency of post-processing, optimize the production line cycle, and reduce production costs.

[0056] The purpose of the above embodiments is to provide a further detailed description of the present invention in conjunction with the accompanying drawings, so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the embodiments disclosed in the present invention, optimization or equivalent substitution of the involved part structures or method steps, as well as the combination of implementation methods in different embodiments without causing structural and principle conflicts, all fall within the protection scope of the present invention.

Claims

1. A device for post-processing of HJT solar cells, characterized in that It includes an optical injection system, an electrical injection system, and a support stage, among which, The support platform is used to support the battery cells to be processed; The light injection system includes a light source, which is positioned toward the support stage to provide light injection to the solar cell to be processed; The electro-injection system includes an electro-injection carrier and metal probes. The electro-injection carrier is configured as a frame structure and is disposed between the support stage and the light source to allow light emitted from the light source to pass through the electro-injection carrier and illuminate the solar cell. A plurality of metal probes are disposed on the side of the electro-injection carrier facing the support stage and arranged in an array to provide electro-injection to the solar cell.

2. The HJT solar cell post-processing device according to claim 1, characterized in that, The support platform is equipped with a heating resistance wire.

3. The HJT solar cell post-processing device according to claim 1 or 2, characterized in that, The light source includes multiple monochromatic or multicolor LED beads, and the emission spectrum wavelength of the LED beads is 450nm-950nm.

4. The HJT solar cell post-processing device according to claim 3, characterized in that, The light source has an intensity of 5 kW / m 2 - 30 kW / m 2 .

5. The HJT solar cell post-processing apparatus according to claim 1 or 2, characterized in that, A cooling device is provided on the side of the light source away from the support platform.

6. The HJT solar cell post-processing apparatus according to claim 5, characterized in that, The cooling device is configured as a water-cooling device and includes a water-cooled plate disposed on the surface of the light source and a cooling pipe passing through the water-cooled plate, wherein the cooling pipe contains flowing coolant.

7. The HJT solar cell post-processing apparatus according to claim 1 or 2, characterized in that, Multiple metal probes are arranged in a straight line to form a probe array. The bases of the metal probes in the probe array are connected as a whole, and the two ends of the probe array are fixedly connected to the electro-injection carrier.

8. The HJT solar cell post-processing apparatus according to claim 7, characterized in that, Multiple probe arrays are arranged in parallel on the electro-injection carrier, and the surface of the electro-injection carrier provides multiple sets of mounting positions. When the probe arrays are mounted in different mounting positions, they have different relative positional relationships with the support platform.

9. The HJT solar cell post-processing apparatus according to claim 1 or 2, characterized in that, The upper surface of the support platform is configured with a conductive structure.

10. The HJT solar cell post-processing apparatus according to claim 1 or 2, characterized in that, The electro-injection system also includes a lifting device that drives the electro-injection carrier to approach or move away from the support platform, so that the metal probe contacts or separates from the battery cell to be processed.

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