Apparatus for passivation repair of solar cells

Abstract

The utility model discloses a kind of passivation repair equipment of solar cell, comprising: at least one first shell, inside hollow setting;Second shell, inside hollow setting;Conveying belt, along first direction extension setting sequentially penetrate first shell and second shell, conveying belt includes the bearing surface for carrying battery piece;At least one ultraviolet light irradiation mechanism, arrangement is in first shell, ultraviolet light irradiation mechanism includes the ultraviolet irradiation end setting towards bearing surface, to form ultraviolet light irradiation area on bearing surface;Heating mechanism, arrangement is in second shell, heating mechanism includes the operation end setting towards bearing surface, to form heating area on bearing surface.The battery piece of the application after passivation process is sequentially carried out ultraviolet light irradiation treatment and annealing treatment, can realize hydrogen activation, promote its migration to defect site, reach the purpose of optimizing passivation effect, improve battery conversion efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of solar cell technology, specifically relating to a passivation repair device for solar cells. Background Technology

[0002] Hydrogen in silicon can interact with almost all impurities and defects, promoting improved cell conversion efficiency. The passivation process for solar cells introduces a large number of hydrogen atoms, utilizing the charge within the silicon wafer to control the charge state of the hydrogen, thereby achieving the purpose of passivating impurities and defects.

[0003] Currently, after passivation, some deposited hydrogen atoms may not be fully activated or distributed in the optimal position, affecting the passivation effect and leading to a decrease in battery efficiency. Utility Model Content

[0004] The purpose of this application is to provide a passivation repair device for solar cells to solve the technical problem that, in the prior art, some deposited hydrogen atoms may not be fully activated or distributed in the optimal position after the passivation process, which affects the passivation effect and leads to a decrease in cell efficiency.

[0005] To achieve the above objectives, this application provides a passivation repair device for solar cells, comprising:

[0006] At least one first housing, internally hollow;

[0007] The second housing is hollow inside;

[0008] A conveyor belt extends along the first direction and sequentially passes through the first housing and the second housing. The conveyor belt includes a bearing surface for carrying battery cells.

[0009] At least one ultraviolet irradiation mechanism is arranged within the first housing, the ultraviolet irradiation mechanism including an ultraviolet irradiation end facing the support surface to form an ultraviolet irradiation area on the support surface;

[0010] A heating mechanism is arranged within the second housing, the heating mechanism including a working end facing the bearing surface to form a heating area on the bearing surface;

[0011] In one or more embodiments, the ultraviolet irradiation mechanism is selected from one of a UVA light source, a UVB light source, and a UVC light source.

[0012] In one or more embodiments, at least one of the ultraviolet irradiation mechanisms is a UVA light source.

[0013] In one or more embodiments, a first ultraviolet irradiation mechanism and a second ultraviolet irradiation mechanism are included, wherein the first ultraviolet irradiation mechanism is a UVA light source, and the second ultraviolet irradiation mechanism is selected from a UVB light source and a UVC light source.

[0014] In one or more embodiments, the second ultraviolet irradiation mechanism is a UVB light source.

[0015] In one or more embodiments, the second ultraviolet irradiation mechanism is located on the side of the first ultraviolet irradiation mechanism near the second housing.

[0016] In one or more embodiments, the ultraviolet irradiation mechanism is provided in a one-to-one correspondence with the first housing, and each ultraviolet irradiation mechanism is arranged inside the corresponding first housing.

[0017] In one or more embodiments, a height adjustment mechanism is further included, the height adjustment mechanism being disposed within the first housing, and the height adjustment structure including a height-adjustable mounting end, on which the ultraviolet irradiation mechanism is disposed.

[0018] In one or more embodiments, the height adjustment mechanism includes:

[0019] Mounting columns, extending vertically;

[0020] A mounting base is sleeved on the mounting column. The mounting base can slide along the mounting column, and the mounting base is provided with mounting holes corresponding to the positions of the mounting column. The mounting end is provided on the side of the mounting base facing the bearing surface.

[0021] A locking element is inserted into the mounting hole, and the locking element abuts against the mounting post.

[0022] In one or more embodiments, a vertically extending height scale is arranged on one side of the mounting column.

[0023] In one or more embodiments, the first housing is provided with heat dissipation holes; the passivation repair device further includes a cooling fan disposed within the heat dissipation holes.

[0024] In one or more embodiments, the heating mechanism includes one or more combinations of metal heating elements, infrared heating elements, and electromagnetic induction heating elements.

[0025] In one or more embodiments, the second housing has an annealing cavity and a cooling cavity arranged sequentially along the first direction, and the heating mechanism is arranged in the annealing cavity.

[0026] The advantages of this application, which differ from existing technologies, are:

[0027] This application enables the sequential ultraviolet irradiation treatment and annealing treatment of passivated solar cells. The ultraviolet irradiation treatment can break the weak Si-H bonds and H bonds in silicon. 2+ H-related defects are eliminated, thereby activating hydrogen, releasing active hydrogen atoms, and promoting their migration to defect sites such as grain boundaries and dislocations, so as to optimize the passivation effect and improve the battery conversion efficiency. The heat energy of annealing can further diffuse hydrogen atoms, making them more evenly distributed at the defect sites, and enabling hydrogen to form more stable Si-H or Si-OH bonds with silicon dangling bonds or oxygen vacancies, thus improving the durability of passivation. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of one embodiment of the passivation repair device for solar cells in this application;

[0030] Figure 2 This is a schematic diagram of another embodiment of the passivation repair device for solar cells in this application;

[0031] Figure 3 This is a schematic diagram of another embodiment of the passivation repair device for solar cells in this application;

[0032] Figure 4 This is a schematic diagram of another embodiment of the passivation repair device for solar cells in this application;

[0033] Figure 5 This is a graph showing the battery efficiency gain data of the battery cells of Examples 1 to 8 of this application relative to the battery cell of Comparative Example 2;

[0034] Figure 6 This is a graph of LID test data for the battery cell of Embodiment 1 of this application;

[0035] Figure 7 This is a graph showing the CID test data of the battery cell in Embodiment 1 of this application. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0037] The presence of numerous impurities and defects in commercial silicon, along with the static degradation inherent in TOPCon solar cells, limits further improvements in their photoelectric conversion efficiency. Hydrogen passivation technology can effectively enhance conversion efficiency and mitigate static degradation in TOPCon solar cells.

[0038] Specifically, hydrogen passivation technology involves injecting electrons or holes to control the charge state of hydrogen, and then using these charged hydrogen states to passivate defects and impurities inside the battery. Currently, the mainstream hydrogen passivation technologies mainly include electro-implanted hydrogen passivation (HEI) and photo-implanted hydrogen passivation (HPI).

[0039] The former (HEI) injects electrons directly into the cell by applying a forward bias voltage during the passivation process of the solar cell. At the same time, it applies temperature to allow hydrogen in the passivation layer to quickly enter the cell. In this way, the non-equilibrium charge carriers entering the cell can regulate the charge state of hydrogen, allowing hydrogen in different charge states to passivate defects and impurities in different charge states.

[0040] The latter (HPI) induces a photovoltaic effect within the solar cell by applying light during the passivation process. This generates a large number of non-equilibrium charge carriers inside the cell. These non-equilibrium charge carriers combine with diffused hydrogen to regulate the hydrogen charge state. This hydrogen then passivates impurities and defects of different forms within the cell, ultimately improving the cell's conversion efficiency.

[0041] Therefore, current passivation processes for solar cells introduce a large number of hydrogen atoms to passivate defects in the silicon wafer. However, during long-term application, the applicant discovered that some of the hydrogen atoms deposited after the passivation process may not be fully activated or distributed in optimal positions, affecting the passivation effect and leading to a decrease in cell efficiency.

[0042] To address the aforementioned issues, the applicant has developed a passivation repair device for solar cells. This device can significantly optimize the passivation effect of solar cells, thereby reducing cell defects and improving cell conversion efficiency.

[0043] Specifically, please refer to Figure 1 , Figure 1 This is a schematic diagram of one embodiment of the passivation repair device for solar cells in this application.

[0044] like Figure 1 As shown, the device includes a first housing 100 and a second housing 200 arranged sequentially along a first direction x, and a conveyor belt 300 that passes through the first housing 100 and the second housing 200 sequentially along the first direction x.

[0045] The first housing 100 and the second housing 200 are both hollow inside; the surface of the conveyor belt 300 is provided with a bearing surface 301 for bearing the battery cell 600.

[0046] An ultraviolet irradiation mechanism 400 is arranged inside the first housing 100. The ultraviolet irradiation mechanism 400 includes an ultraviolet irradiation end 401 facing the bearing surface 301, thereby forming an ultraviolet irradiation area 302 on the bearing surface 301.

[0047] The second housing 200 has a heating mechanism 500 inside. The heating mechanism 500 includes a working end 501 facing the bearing surface 301, thereby forming a heating area 303 on the bearing surface 301.

[0048] By placing the battery cell 600 on the bearing surface 301 of the conveyor belt 300, the battery cell 600 can pass through the ultraviolet irradiation area 302 and the heating area 303 in sequence under the conveying action of the conveyor belt 300, thereby realizing the ultraviolet irradiation treatment and annealing treatment of the battery cell 600 in sequence.

[0049] The passivation repair device of this application is for a solar cell 600 with a passivation layer formed thereon. The solar cell 600 can be any solar cell in the art that needs to undergo a passivation process. For example, the solar cell can be an aluminum back field (BSF) cell, a PERC cell, a heterojunction (HJT) cell, a TOPCon cell, a BC cell, etc., all of which can achieve the effect of this embodiment.

[0050] In this context, a passivation layer refers to a layer structure deposited on the surface of a silicon wafer through a passivation process. The passivation process reduces surface carrier recombination losses and suppresses interface defects, thereby optimizing performance. For example, the passivation layer can be an alumina layer, a silicon nitride layer, a silicon dioxide layer, a hydrogenated amorphous silicon layer, etc.

[0051] More specifically, for TOPCon cells, the passivation layer can be an aluminum oxide layer on the light-receiving surface, or a back passivation contact structure composed of an ultrathin tunneling oxide layer and a phosphorus-doped polycrystalline silicon layer on the back surface; for half-cell processes, the passivation layer can be a SiO2 / SiNx stack on the cut surface, and so on.

[0052] In one embodiment, the passivation layer can be deposited by a passivation process on the light-receiving surface and / or back-lighting surface of the solar cell 600. Since, in the solar cell fabrication process, after the passivation process on the light-receiving surface and / or back-lighting surface of the solar cell 600, further screen printing and sintering processes are required on the light-receiving surface and / or back-lighting surface to form grid electrodes, the high temperature during sintering can lead to hydrogen loss and secondary hydrogen migration. To avoid the high-temperature sintering affecting the effect of ultraviolet irradiation treatment, after the solar cell 600 completes the high-temperature sintering and laser-induced sintering (LIF) process, it can be placed on the bearing surface 301 of the conveyor belt 300, thereby sequentially completing ultraviolet irradiation and annealing treatments.

[0053] In another embodiment, the passivation layer can be deposited by a passivation process on the cut surfaces of the solar cell 600. In the half-cell process of solar cell fabrication, in order to reduce series resistance loss and improve module power, by laser-cutting a standard-sized solar cell 600 into two equal-sized half-cells 600, the current through each main grid can be reduced to 1 / 2 of the original, and the internal loss can be reduced to 1 / 4 of the whole cell, thereby improving the module power. During the dicing and cutting process of the solar cell 600, new defects are introduced at the cutting edges, so the edges need to be passivated to reduce defects, thereby forming a passivation layer on the cut surfaces. The solar cells 600 that have undergone the dicing and passivation process can be placed on the bearing surface 301 of the conveyor belt 300, and then undergo ultraviolet irradiation and annealing treatments in sequence.

[0054] Since some hydrogen in silicon is deposited before migrating to the passivation site after the passivation process, the device in this embodiment first breaks the weakly bonded Si-H bonds and H2 in silicon by subjecting the solar cell 600 to ultraviolet irradiation treatment. + H-related defects are eliminated, thereby activating hydrogen, releasing active hydrogen atoms, and promoting their migration to defect sites such as grain boundaries and dislocations, thus optimizing the passivation effect and improving the battery conversion efficiency. In particular, for the 600 battery cell after dicing and passivation, ultraviolet irradiation treatment can drive the migration of hydrogen atoms at the edge, further passivating the diced edge and reducing edge recombination.

[0055] Furthermore, the solar cell 600, which has been treated with ultraviolet light irradiation, is annealed. The heat energy from the annealing process allows hydrogen atoms to diffuse further, making them more evenly distributed at the defects and enhancing the overall passivation effect.

[0056] In addition, after ultraviolet irradiation treatment, some hydrogen will be released as unstable H+. + The passivation material exists in a certain form and can easily escape in subsequent processes. Annealing can help hydrogen and silicon dangling bonds or oxygen vacancies form more stable Si-H or Si-OH bonds, thus improving the durability of passivation.

[0057] In particular, for 600 solar cells that have undergone dicing and passivation, since cutting introduces high-density defects at the edges, the heat energy of annealing can allow hydrogen to penetrate deeper into the damaged area, repair deep-level defects, reduce edge recombination, and at the same time, annealing can also alleviate localized stress concentration caused by dicing and cutting.

[0058] Specifically, in this embodiment, the ultraviolet irradiation mechanism 400 is a UVA light source 402, where UVA refers to low-frequency long-wave light with a wavelength greater than or equal to 315nm and less than or equal to 400nm; in other embodiments, the ultraviolet irradiation mechanism 400 may also use a UVB light source 403 or a UVC light source, where UVB refers to mid-frequency medium-wave light with a wavelength greater than or equal to 280nm and less than 315nm, and UVC refers to high-frequency low-wave light with a wavelength greater than or equal to 100nm and less than 280nm.

[0059] In this embodiment, UVA light source 402 is used for irradiation treatment. UVA has the lowest energy, providing sufficient energy to release active hydrogen atoms while minimizing damage to the solar cell 600. When UVA irradiation treatment is used, surface defects of the solar cell 600 can be fully repaired.

[0060] To control the irradiation dose received by the solar cell 600 and avoid insufficient or excessive passivation repair, the irradiation dose received by the surface of the solar cell 600 during ultraviolet irradiation treatment in this embodiment can be 0.5 W / m². 2 ~1.0W / m 2 The irradiance can be adjusted by changing the spectral power of the UVA light source 402 and the distance between the UVA light source 402 and the solar cell 600. For example, the spectral power of the UVA light source 402 can be 500W, and the distance between the UVA light source 402 and the solar cell 600 can be 300mm.

[0061] In this embodiment, the heating mechanism 500 is a metal heating tube 502. In other embodiments, the heating mechanism 500 can be an infrared heating element, an electromagnetic induction heating element, or other elements that can achieve the heating effect, and all can achieve the effect of this embodiment.

[0062] To ensure the effectiveness of ultraviolet irradiation treatment, in one embodiment, the ultraviolet irradiation treatment time can be 0.7s to 0.9s, that is, each part of the battery cell 600 can stay in the ultraviolet irradiation area 302 for 0.7s to 0.9s.

[0063] Because H atoms with different mobility exist inside the silicon wafer + H 0 and H -Hydrogen exists in three charge states, each corresponding to a different defect type. By controlling the annealing time and temperature, the different charge states of hydrogen can be modulated, thereby optimizing the passivation effect.

[0064] In one embodiment, the annealing temperature can be 100°C to 230°C, and the treatment time can be 5s to 10s, thereby allowing hydrogen in the dielectric layer to permeate into the N-type and P-type regions inside the battery, generating H in the N-type region. 0 and H + H forms in the P-type region 0 and H - This helps to passivate defects and improve the efficiency of the solar cells by 600%.

[0065] More preferably, the annealing temperature can be 150°C to 200°C and the processing time can be 5s to 10s, that is, each part of the solar cell 600 can stay in the heating zone 303 for 5s to 10s, thereby maximizing the efficiency gain of the solar cell 600.

[0066] When the annealing temperature is too high or the processing time is too long, excessive annealing will occur, affecting the passivation effect; while when the annealing temperature is too low or the processing time is too short, sufficient passivation will not be achieved.

[0067] Specifically, in this embodiment, the conveyor belt 300 maintains a constant speed, and the processing time is controlled by controlling the extension length of the ultraviolet irradiation area 302 and the heating area 303. In another embodiment, the conveyor belt 300 can also move intermittently. When the battery cell 600 reaches the ultraviolet irradiation area 302 or the heating area 303, the conveyor belt 300 stops moving until the processing is completed and then starts moving again. Both of these methods can achieve the effect of this embodiment.

[0068] In the above embodiments, ultraviolet irradiation treatment is performed using a single UVA light source 402. The UVA light source 402 has relatively low energy, which is sufficient to repair surface defects in the solar cell 600. In another embodiment, before or after surface repair using the UVA light source 402, a higher-energy ultraviolet light source can be used for deep repair of the interior of the solar cell 600. Please refer to [link to relevant documentation]. Figure 2 , Figure 2 This is a schematic diagram of another embodiment of the passivation repair device for solar cells in this application.

[0069] like Figure 2As shown, the device in this embodiment includes two first housings 100 arranged sequentially along the first direction x. A UVA light source 402 is arranged inside the first housing 100 farther from the second housing 200, and a UVB light source 403 is arranged inside the first housing 100 closer to the second housing 200. This allows the solar cell 600 to be subjected to UVA irradiation and UVB irradiation treatments in sequence. By using the higher-energy UVB light source 403 to perform deep repair inside the solar cell 600, the strongly bonded Si-H bonds are broken, and deep-level defects are repaired.

[0070] To avoid insufficient passivation repair due to excessively short irradiation time, the UVB irradiation treatment time in this embodiment can be 0.7s to 0.9s, that is, the dwell time of each part of the battery cell 600 in the ultraviolet irradiation area of ​​the UVB light source 403 can be 0.7s to 0.9s.

[0071] To control the irradiation dose received by the solar cell 600 and avoid insufficient or excessive passivation repair, the irradiation dose received by the surface of the solar cell 600 during UVB irradiation treatment in this embodiment can be 5.0 W / m². 2 ~6.0W / m 2 The irradiance can be controlled by adjusting the spectral power of the UVB light source 403 and its distance from the surface of the solar cell 600. For example, the spectral power of the UVB light source 403 can be 15W, and the distance between the UVB light source 403 and the solar cell 600 can be 10cm.

[0072] In this embodiment, the UVA light source 402 and the UVB light source 403 are arranged sequentially along the first direction x, thereby sequentially performing UVA irradiation treatment and UVB irradiation treatment on the battery cell 600 to achieve defect repair from the surface to the interior of the battery cell 600. In other embodiments, the UVB light source 403 and the UVA light source 402 can also be arranged sequentially along the first direction x, thereby sequentially performing UVB irradiation treatment and UVA irradiation treatment on the battery cell 600, which can also achieve the effect of this embodiment to a certain extent, but the passivation optimization effect may be weaker than the technical solution of this embodiment.

[0073] In this embodiment, an ultraviolet irradiation mechanism 400 is arranged inside each first housing 100, and the battery cell 600 is subjected to UVA and UVB irradiation treatment in sequence through two second housings 100 arranged in sequence. In other embodiments, multiple ultraviolet irradiation mechanisms arranged in sequence can also be arranged inside each first housing 100. For example, UVA light source and UVB light source arranged in sequence can be arranged inside the first housing 100, which can also achieve the effect of this embodiment.

[0074] It should be noted that the above embodiments only show the technical solutions of separate UVA irradiation treatment and sequential UVA and UVB irradiation treatment. In other embodiments, the device may only include a first housing 100 with a UVB light source 403 or a UVC light source arranged therein, or the device may include multiple first housings 100, each of which may independently arrange one of the UVA light source 402, UVB light source 403 and UVC light source. All of these can achieve the effects of this embodiment to a certain extent.

[0075] In the above embodiments, the second housing 200 contains only a single cavity. The annealed battery cell 600 is directly output from the second housing 200 by the conveyor belt 300. Excessive temperature gradients may induce defects in the battery cell 600. To avoid this problem, please refer to [reference needed]. Figure 3 , Figure 3 This is a schematic diagram of another embodiment of the passivation repair device for solar cells in this application.

[0076] like Figure 3 As shown, in this embodiment, the second housing 200 includes an annealing chamber 201 and a cooling chamber 202 arranged sequentially along the first direction x. The two are isolated from each other and have an opening for the conveyor belt 300 to pass through. The heating mechanism 500 is arranged inside the annealing chamber 201. After the battery cell 600 is annealed, it can enter the cooling chamber 202 for slow cooling to avoid problems such as the grid electrode falling off due to excessive temperature gradient.

[0077] In the above embodiments, the ultraviolet irradiation mechanism 400 is fixed to the top surface of the first housing 100, and the height of the ultraviolet irradiation mechanism 400 is fixed. Therefore, it is impossible to adjust the height of the ultraviolet irradiation mechanism 400 in real time based on the irradiation requirements of the battery cell 600. To solve this problem, please refer to... Figure 4 , Figure 4 This is a schematic diagram of another embodiment of the passivation repair device for solar cells in this application.

[0078] like Figure 4 As shown, in this embodiment, the device includes a first housing 100 and a second housing 200 arranged sequentially along the first direction x. The first housing 100 is equipped with a UVA light source 402 and a height adjustment mechanism 700.

[0079] The height adjustment mechanism 700 includes a height-adjustable mounting end 705, on which the UVA light source 402 is arranged, thereby allowing the distance between the UVA light source 402 and the solar cell 600 to be adjusted in real time, thereby adjusting the irradiance on the surface of the solar cell 600.

[0080] Specifically, in this embodiment, the height adjustment mechanism 700 includes a mounting post 701 and a mounting base 702. The mounting post 701 extends vertically and its two ends are fixed to the top and bottom surfaces of the first housing 100, respectively. The mounting base 702 is sleeved on the mounting post 701 and can slide along the mounting post 701. The mounting base 702 is provided with mounting holes (not shown in the figure) corresponding to the positions of the mounting post 701. The mounting end 705 is provided on the side of the mounting base 702 facing the bearing surface 301.

[0081] The height adjustment mechanism 700 also includes a locking member 703 inserted into the mounting hole, and the locking member 703 abuts against the mounting post 701. The height of the mounting base 702 can be adjusted by loosening the locking member 703, and the mounting base 702 can be fixed by tightening the locking member 703 after the height adjustment is completed.

[0082] To facilitate operators in controlling the height of the UVA light source 402, a vertically extending height scale 704 is also provided on the side of the mounting column 701 in this embodiment.

[0083] It should be noted that this embodiment only shows one optional height adjustment mechanism 700. In other embodiments, any lifting mechanism commonly used in the art can be applied to the first housing 100 of this embodiment, such as a lead screw and nut structure, etc., and can achieve the effect of this embodiment.

[0084] Since the ultraviolet irradiation mechanism 400 generates a large amount of heat during operation, in order to avoid heat accumulation inside the first housing 100, a heat dissipation hole 101 is provided on the top of the first housing 100 in this embodiment, and a cooling fan 800 is provided inside the heat dissipation hole 101; in other embodiments, the heat dissipation hole 101 may also be arranged in other positions of the first housing 100, but it is preferred to be arranged on the back of the ultraviolet irradiation end 401 of the ultraviolet irradiation mechanism 400 to avoid ultraviolet rays from escaping.

[0085] The passivation repair equipment for solar cells based on the above embodiments can sequentially perform ultraviolet irradiation treatment and annealing treatment on the passivated solar cell 600. The ultraviolet irradiation treatment can break the weak Si-H bonds and H bonds in silicon. 2+ H-related defects are eliminated, thereby activating hydrogen, releasing active hydrogen atoms, and promoting their migration to defect sites such as grain boundaries and dislocations, thus optimizing the passivation effect and improving battery conversion efficiency. The heat energy of annealing can further diffuse hydrogen atoms, making them more evenly distributed at the defect sites, and enabling hydrogen to form more stable Si-H or Si-OH bonds with silicon dangling bonds or oxygen vacancies, thereby improving the durability of passivation.

[0086] In particular, for the 600 solar cell that has undergone dicing and passivation, the cutting process introduces high-density defects at the edges. Ultraviolet irradiation can laser passivate hydrogen in the passivation layer, but some hydrogen atoms may not have completely migrated to the passivation sites. The heat energy from further annealing can further diffuse the hydrogen atoms, making them more evenly distributed at the defects and enhancing the overall passivation effect. In particular, for the 600 solar cell that has undergone dicing and passivation, the heat energy from annealing can allow hydrogen to penetrate deeper into the damaged area, repair deep-level defects, reduce edge recombination, and also alleviate the localized stress concentration caused by dicing and cutting.

[0087] The beneficial effects of the technical solution of this application will be further explained in detail below with reference to specific embodiments.

[0088] Example 1:

[0089] A method for fabricating a solar cell, comprising:

[0090] The solar cells, which have undergone the first passivation, screen printing, sintering, LIF, testing, sorting, dicing, and second passivation, are placed in... Figure 4 On the conveyor belt bearing surface of the passivation repair equipment shown, the battery cells are subjected to UVA irradiation treatment and annealing treatment in sequence.

[0091] In the first passivation process, an aluminum oxide layer, a silicon nitride layer, and a silicon oxide layer are grown sequentially on the front side of the silicon substrate, and a phosphorus-doped polycrystalline silicon layer and a silicon nitride layer are grown sequentially on the back side of the silicon substrate.

[0092] The dicing process cuts the solar cells into two cells of the same size;

[0093] The second passivation process grows an aluminum oxide layer on the cut surface of the solar cell;

[0094] In the UVA irradiation treatment, the front side of the solar cell is irradiated with a UVA light source at a distance of 300mm. The UVA light source has a wavelength of 365nm and a spectral power of 500W, resulting in an irradiation dose of 0.8W / m on the front side of the solar cell. 2 Irradiation treatment time: 0.8s;

[0095] The annealing temperature for the annealing treatment is 150℃, and the annealing time is 5s.

[0096] Examples 2 to 8:

[0097] A method for preparing a solar cell is basically the same as in Example 1, using... Figure 4 The passivation repair equipment shown performs UVA irradiation treatment and annealing treatment on the solar cells in sequence, with the following differences:

[0098] The annealing temperature and / or annealing time are different for annealing treatment.

[0099] Please refer to the table below for the parameters of the annealing treatment in Examples 1 to 8 above.

[0100]

[0101]

[0102] Comparative Example 1:

[0103] A solar cell is prepared using a method basically the same as in Example 1, except that:

[0104] No second passivation process is performed on the solar cells, and no further processing is carried out after the dicing process. Figure 4 The passivation repair equipment shown is used for processing.

[0105] Comparative Example 2:

[0106] A solar cell is prepared using a method basically the same as in Example 1, except that:

[0107] No further processing is performed after the second passivation process. Figure 4 The passivation repair equipment shown is used for processing.

[0108] Example 1: Photoelectric Performance Analysis

[0109] The photoelectric conversion efficiency, i.e., the battery efficiency eta, of the solar cells of Example 1 and Comparative Examples 1 and 2 was measured, and the data in the table below were obtained.

[0110] The formula for calculating the cell efficiency of a solar cell is as follows:

[0111]

[0112] In the formula, η is the battery efficiency, and P in V is the incident light power. OC J is the open-circuit voltage. SC is the short-circuit current density, and FF is the fill factor.

[0113]

[0114] As shown in the table above, the battery efficiency gain after the second passivation is 0.08% compared to the original cell. Furthermore, by subjecting the passivated cells to UVA irradiation and annealing, the battery efficiency can be significantly improved, with a gain of 0.14%.

[0115] Furthermore, the cell efficiency of the solar cells in Examples 1 to 8 was measured, and their cell efficiency gain relative to that of the solar cell in Comparative Example 2 was calculated, resulting in... Figure 5 , Figure 5This is a graph showing the battery efficiency gain data of the battery cells of Examples 1 to 8 of this application relative to the battery cell of Comparative Example 2.

[0116] like Figure 5 As shown, both low-temperature short-time annealing at 100℃~230℃ for 5s~10s after UVA irradiation can improve battery efficiency. Among them, annealing at 150℃~200℃ for 5s~10s can achieve the maximum battery efficiency. This is mainly because too low an annealing temperature will lead to insufficient annealing and limited passivation optimization effect, while too high an annealing temperature will lead to over-annealing, resulting in a reduction in passivation optimization effect.

[0117] Example 2: Reliability Testing

[0118] To verify whether the ultraviolet irradiation treatment and annealing treatment of this application would affect the reliability of the solar cell, the applicant conducted a static decay test on the solar cell of Example 1 and obtained the data in the table below.

[0119]

[0120] As shown in the table above, the battery cell in Example 1 showed no significant degradation after being left to stand for 12 hours, indicating that the degradation during standing was acceptable.

[0121] Furthermore, the solar cells of Example 1 were subjected to light-induced degradation (LID) and current-induced degradation (CID) tests to obtain... Figure 6 and Figure 7 , Figure 6 This is a graph showing the LID test data of the battery cell in Embodiment 1 of this application. Figure 7 This is a graph showing the CID test data of the battery cell in Embodiment 1 of this application.

[0122] like Figure 6 and Figure 7 As shown, the solar cell of Example 1 did not show significant degradation under long-term light exposure and high current density, and passed the LID and CID tests.

[0123] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0124] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A passivation repair device for solar cells, characterized in that, include: At least one first housing, internally hollow; The second housing is hollow inside; A conveyor belt extends along a first direction and sequentially passes through the first housing and the second housing. The conveyor belt includes a support surface for carrying battery cells. At least one ultraviolet irradiation mechanism is arranged within the first housing, the ultraviolet irradiation mechanism including an ultraviolet irradiation end facing the support surface to form an ultraviolet irradiation area on the support surface; A heating mechanism is arranged within the second housing, the heating mechanism including a working end facing the bearing surface to form a heating area on the bearing surface.

2. The passivation repair equipment according to claim 1, characterized in that, The ultraviolet irradiation mechanism is selected from one of the UVA, UVB, and UVC light sources.

3. The passivation repair equipment according to claim 2, characterized in that, At least one of the ultraviolet irradiation mechanisms is a UVA light source.

4. The passivation repair equipment according to claim 3, characterized in that, It includes a first ultraviolet irradiation mechanism and a second ultraviolet irradiation mechanism, wherein the first ultraviolet irradiation mechanism is a UVA light source, and the second ultraviolet irradiation mechanism is selected from a UVB light source and a UVC light source.

5. The passivation repair equipment according to claim 4, characterized in that, The second ultraviolet irradiation mechanism is a UVB light source; and / or, The second ultraviolet irradiation mechanism is located on the side of the first ultraviolet irradiation mechanism near the second housing.

6. The passivation repair equipment according to claim 1, characterized in that, The ultraviolet irradiation mechanism is configured in a one-to-one correspondence with the first housing, and each ultraviolet irradiation mechanism is arranged inside the corresponding first housing.

7. The passivation repair equipment according to claim 1, characterized in that, It also includes a height adjustment mechanism, which is arranged inside the first housing, and the height adjustment mechanism includes a height-adjustable mounting end, on which the ultraviolet irradiation mechanism is arranged.

8. The passivation repair equipment according to claim 7, characterized in that, The height adjustment mechanism includes: Mounting columns, extending vertically; A mounting base is sleeved on the mounting column. The mounting base can slide along the mounting column, and the mounting base is provided with mounting holes corresponding to the positions of the mounting column. The mounting end is provided on the side of the mounting base facing the bearing surface. A locking element is inserted into the mounting hole, and the locking element abuts against the mounting post.

9. The passivation repair equipment according to claim 8, characterized in that, A vertically extending height scale is arranged on one side of the mounting column.

10. The passivation repair equipment according to claim 1, characterized in that, The first housing is provided with heat dissipation holes; the passivation repair device also includes a cooling fan arranged in the heat dissipation holes.

11. The passivation repair equipment according to claim 1, characterized in that, The heating mechanism includes one or more combinations of metal heating elements, infrared heating elements, and electromagnetic induction heating elements; and / or, The second housing has an annealing chamber and a cooling chamber arranged sequentially along the first direction, and the heating mechanism is arranged in the annealing chamber.

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