A method of manufacturing a solar cell, a solar cell, and a photovoltaic module

Abstract

The application relates to a solar cell manufacturing method, a solar cell and a photovoltaic module. The solar cell manufacturing method comprises the following steps: printing a slurry on a cell piece, and performing drying and sintering; making the cell piece be at a first preset temperature, and making a first light beam irradiate the cell piece; making the cell piece be at a second preset temperature, and making a second light beam irradiate the cell piece; and the second preset temperature is lower than the first preset temperature. In the application, a first light annealing is performed on the cell piece, a combination with a recombination center is generated, a non-recombination center is formed, and thus the recombination center in the solar cell is reduced; a second light annealing is performed on the cell piece, the density of Si dangling bonds is reduced, the interface state of the solar cell is reduced, the passivation effect is improved, and the annealing process of the solar cell is completed. Therefore, through the two light annealings, the open circuit voltage, the fill factor and the photoelectric conversion efficiency of the solar cell are improved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a method for manufacturing a solar cell, a solar cell, and a photovoltaic module. Background Technology

[0002] Photovoltaic modules can directly convert solar radiation energy into electrical energy, mainly based on the photovoltaic effect of crystalline silicon. When the photons of sunlight are absorbed by the semiconductor crystalline silicon, electron-hole pairs are generated. When these electron-hole pairs reach the pn junction composed of p-type and n-type crystalline silicon, they are separated to both sides of the pn junction by the junction electric field. When an external load is connected, a photocurrent is formed, and electrical energy is output.

[0003] The photoelectric conversion efficiency of existing photovoltaic modules is relatively low, and how to improve the photoelectric conversion efficiency of photovoltaic modules is an urgent problem to be solved. Summary of the Invention

[0004] This application provides a method for manufacturing a solar cell, a solar cell, and a photovoltaic module, to solve the aforementioned technical problem of low photoelectric conversion efficiency in photovoltaic modules.

[0005] This application provides a method for manufacturing a solar cell, comprising:

[0006] The paste is printed onto the battery cells, which are then dried and sintered.

[0007] The battery cell is brought to a first preset temperature, and the first light beam irradiates the battery cell.

[0008] The battery cell is brought to a second preset temperature, and the second light beam irradiates the battery cell.

[0009] The second preset temperature is lower than the first preset temperature.

[0010] In one possible implementation, the first preset temperature T1 satisfies: 600℃≤T1≤700℃.

[0011] In one possible implementation, the second preset temperature T2 satisfies: 100℃≤T2≤200℃.

[0012] In one possible implementation, the wavelength of the first beam is equal to the wavelength of the second beam.

[0013] In one possible implementation, the wavelength of the first beam satisfies: 400nm~800nm.

[0014] In one possible implementation, the time t1 during which the first beam illuminates the solar cell satisfies: 8s ≤ t1 ≤ 14s.

[0015] In one possible implementation, the time t2 during which the second beam illuminates the solar cell satisfies: 15s ≤ t2 ≤ 30s.

[0016] In one possible implementation, the battery cell has opposing first and second sides;

[0017] Before the steps of printing paste onto the solar cell and drying / sintering, the method for manufacturing the solar cell includes:

[0018] An aluminum oxide layer is formed on the first side and the second side;

[0019] A silicon oxide layer and a silicon nitride layer are formed on the first side, and a silicon nitride layer is formed on the second side.

[0020] In one possible implementation, the second side has a first region and a second region, the first region being provided with a first conductive structure and the second region being provided with a second conductive structure, the first conductive structure and the second conductive structure having different polarities;

[0021] Before the step of forming a silicon oxide layer and a silicon nitride layer on the first side, and forming a silicon nitride layer on the second side, the method for manufacturing the solar cell further includes:

[0022] The first conductive structure is formed in the first region, and the second conductive structure is formed in the second region;

[0023] The solar cell is texturized.

[0024] In one possible implementation, the steps of forming the first conductive structure in the first region and forming the second conductive structure in the second region include:

[0025] Provide a base;

[0026] A first conductive structure is formed on the surface of the substrate;

[0027] Laser etching is performed on the first conductive structure located on the second side, excluding the first region;

[0028] A second conductive structure is formed on the outside of the substrate and the first conductive structure;

[0029] Laser etching is performed on the second conductive structure located on the second side, excluding the second region.

[0030] Etch the first conductive structure and the second conductive structure located on the first side.

[0031] The solar cell provided in this application embodiment is manufactured by the solar cell manufacturing method described above.

[0032] This application provides a photovoltaic module including the solar cell described above.

[0033] In this application, during the first photo-annealing, as photons from the first beam are injected into the solar cell and the temperature rises, a large number of holes are generated in the solar cell. The Si-H bonds and NH bonds in the first and second passivation layers break, releasing H. The H diffuses into the first conductive structure, the second conductive structure, and the substrate 1, and is converted into [a specific substance] under the influence of the holes. , By combining with recombination centers to form non-recombination centers, recombination in the solar cell is reduced, thereby improving the open-circuit voltage, fill factor, and photoelectric conversion efficiency. During the second photo-annealing process, as photons from the second beam are injected into the solar cell and under the influence of the second preset temperature, H continues to diffuse into the substrate 1. This reduces the density of Si dangling bonds, lowers the interface states of the solar cell, improves the passivation effect, and completes the annealing process of the solar cell.

[0034] The second preset temperature is lower than the first preset temperature, which can prevent the solar cell from being damaged under continuous high temperature.

[0035] By performing two photo-annealing processes, recombination in solar cells is reduced, the passivation effect of solar cells is improved, and the photoelectric conversion efficiency of solar cells is increased.

[0036] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the structure of the solar cell involved in this application in some embodiments;

[0038] Figure 2 For including Figure 1 A schematic diagram of the structure of a photovoltaic module with solar cells;

[0039] Figure 3 The flowcharts for some embodiments of the method for manufacturing the solar cell involved in this application are shown below;

[0040] Figure 4 A schematic diagram of the structure of the solar cell involved in the step of providing the substrate;

[0041] Figure 5 A schematic diagram of the structure of a solar cell involved in the step of forming a first conductive structure on the surface of a substrate;

[0042] Figure 6A schematic diagram of the structure of a solar cell involved in the step of laser etching the first conductive structure located on the second side, excluding the first region;

[0043] Figure 7 A schematic diagram of the structure of a solar cell involved in the step of forming a second conductive structure on the outside of the substrate and the first conductive structure;

[0044] Figure 8 A schematic diagram of the structure of the solar cell involved in the step of laser etching the second conductive structure located on the second side, excluding the second region;

[0045] Figure 9 A schematic diagram of the structure of a solar cell involved in the step of etching the first conductive structure and the second conductive structure located on the first side.

[0046] Figure label:

[0047] a - Zone 1; b - Zone 2; c - Interval zone;

[0048] 1-Substrate; 11-First side; 12-Second side; 2-First tunneling layer; 3-First doped conductive layer; 4-Second tunneling layer; 5-Second doped conductive layer; 6-Alumina layer; 7-Silicon nitride layer; 8-Silicon oxide layer;

[0049] 10 - Front packaging structure; 20 - Front film layer; 30 - Battery string; 40 - Back film layer; 50 - Back packaging structure.

[0050] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0051] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0052] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0053] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0054] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0055] It should be noted that the directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0056] The first aspect of this application provides a solar cell. Figure 1 This is a schematic diagram of the structure of the solar cell involved in this application in some embodiments. For example... Figure 1 As shown, the solar cell includes a cell having: a substrate 1, a first conductive structure, and a second conductive structure. The first conductive structure includes a first tunneling layer 2 and a first doped conductive layer 3, and the second conductive structure includes a second tunneling layer 4 and a second doped conductive layer 5.

[0057] The substrate 1 is of the first conductivity type, and one of the first doped conductive layer 3 and the second doped conductive layer 5 is of the first conductivity type, while the other is of the second conductivity type. The following description uses the example of the first doped conductive layer 3 being of the second conductivity type and the second doped conductive layer 5 being of the first conductivity type.

[0058] For example, the first conductivity type is N-type, with N-type doping elements present in the substrate 1 and the second doped conductive layer 5. These N-type doping elements can be Group V elements such as phosphorus (P), arsenic (As), bismuth (Bi), and antimony (Sb). The second conductivity type is P-type, with P-type doping elements present in the first doped conductive layer 3. These P-type doping elements can be Group III elements such as boron (B), aluminum (Al), gallium (Ga), and indium (In). It is understood that in other embodiments, the first conductivity type can be P-type, and the second conductivity type can be N-type.

[0059] The solar cell has a first side 11 and a second side 12 opposite to each other along its thickness direction. The first side 11 can be the front of the solar cell, that is, the side directly exposed to sunlight, and the second side 12 can be the back of the solar cell, that is, the side not directly exposed to sunlight. Both the first side 11 and the second side 12 can receive sunlight and convert light energy into electrical energy.

[0060] The solar cell also includes a first electrode and a second electrode. The first electrode is electrically connected to a first conductive structure, and the second electrode is electrically connected to a second conductive structure. Electrical connection means that the solar cell can transmit current when exposed to sunlight.

[0061] The second side 12 is divided into a first zone a, a second zone b, and a spacer zone c. Zones a and b are arranged alternately, and spacer zone c is located between zones a and b. The first conductive structure is located in zone a, and the second conductive structure is located in zone b, meaning the first and second conductive structures are on the same side of the solar cell (generally the side not directly exposed to sunlight). This reduces parasitic absorption of sunlight by the first and second conductive structures. Correspondingly, the first and second electrodes are also located on the same side of the solar cell (generally the side not directly exposed to sunlight), i.e., in back contact with the cell. This reduces the shading of the solar cell by the first and second electrodes, which helps to increase the amount of sunlight absorbed by the solar cell.

[0062] like Figure 1 As shown, the first side 11 of the battery cell has a first passivation layer, and the second side 12 of the battery cell has a passivation layer.

[0063] For example, the first passivation layer includes an aluminum oxide layer 6, a silicon oxide layer 8, and a silicon nitride layer 7, and the second passivation layer includes an aluminum oxide layer 6 and a silicon nitride layer 7. The aluminum oxide layer 6, silicon oxide layer 8, and silicon nitride layer 7 can also serve as anti-reflection layers to reduce sunlight reflection and increase the absorption of sunlight by the solar cell.

[0064] In some other embodiments, the solar cell can also be a tandem cell, comprising a back contact bottom cell and a perovskite top cell, the perovskite top cell being electrically connected to the front side of the back contact bottom cell, the back contact bottom cell being the aforementioned back contact cell. The tandem cell also includes an intermediate connecting layer connecting the back contact bottom cell and the perovskite top cell. The intermediate connecting layer can be selected from a transparent material with a high refractive index, such as a transparent conductive metal oxide thin film (ITO). An effective intermediate connecting layer needs to have high light transmittance to reduce light reflection and absorption at the intermediate connecting layer interface, and good conductivity to reduce the impact of series resistance on device performance.

[0065] In some other embodiments, the solar cell can also be an emitter-back passivated cell (PERC), a tunnel oxide passivated contact cell (TOPCON), a heterojunction with intrinsic thin-layer (HIT), a perovskite solar cell (PSC), etc.

[0066] For TOPCon cells, along their thickness direction, the TOPCon cell sequentially includes a silver electrode, a front-surface silicon nitride passivation layer, a boron-doped emitter, an N-type substrate silicon layer, a diffused doped layer, an ultrathin silicon oxide layer, doped polycrystalline silicon, silicon nitride, and the silver electrode. The back of the cell consists of an ultrathin silicon oxide layer (1nm~2nm) and a phosphorus-doped microcrystalline amorphous mixed Si film, which together form a passivation contact structure. This structure can block minority carrier recombination, increasing the cell's open-circuit voltage and short-circuit current. The ultrathin oxide layer allows majority carrier electrons to tunnel into the polycrystalline silicon layer while blocking minority carrier recombination. The excellent passivation effect of the ultrathin silicon oxide and heavily doped silicon film causes band bending on the silicon wafer surface, resulting in a field passivation effect. This significantly increases the probability of electron tunneling, reduces contact resistance, and improves the cell's open-circuit voltage and short-circuit current, thereby increasing the cell's conversion efficiency.

[0067] For HIT cells, along their thickness direction, HIT cells sequentially include a front low-temperature silver electrode, a front conductive film, an N-type amorphous silicon film, an intrinsic amorphous silicon film, an N-type substrate silicon layer, an intrinsic amorphous silicon film, a P-type amorphous silicon film, a back conductive film, and a back low-temperature silver electrode.

[0068] For PERC cells, along their thickness direction, the PERC cell sequentially includes a front surface silver electrode, a front surface silicon nitride passivation layer, a phosphorus emitter layer, a P-type substrate silicon layer, a local aluminum back field, a metallic aluminum back electrode, and a back passivation layer (Al2O3 / SiN). x PERC cells use a passivation film to passivate the back surface, replacing the all-aluminum back surface, which enhances light reflection on the inner back of the silicon substrate, reduces the recombination rate on the back surface, and improves the cell efficiency by 0.5%-1%.

[0069] For a perovskite solar cell, along its thickness direction, the perovskite solar cell sequentially includes a substrate material, a conductive thin film, an electron transport layer (titanium dioxide), a perovskite absorption layer (hole transport layer), and a metal cathode. Perovskite materials have a high light absorption coefficient and a long carrier diffusion distance. After the photons absorbed by the perovskite material are converted into electrons, they are easily collected by the electrodes with low loss, thus generating high photogenerated voltage and current, making perovskite exhibit high photoelectric conversion efficiency.

[0070] A second aspect of this application provides a photovoltaic module, which includes solar cells. The solar cells are electrically connected by solder strips to form a cell string 30. When a first electrode and a second electrode are respectively located on opposite sides of a solar cell, the solder strips extend from one side of the solar cell to the opposite side of an adjacent solar cell; when both the first electrode and the second electrode are located on one side of the solar cell, the solder strips extend from the back surface of the solar cell to the back surface of an adjacent solar cell.

[0071] Figure 2 For including Figure 1 A schematic diagram of the structure of a photovoltaic module using solar cells. (See diagram below.) Figure 2 As shown, the photovoltaic module also includes: a front encapsulation structure 10, a front film layer 20, a cell string 30, a back film layer 40, and a back encapsulation structure 50. The front encapsulation structure 10, the front film layer 20, the back film layer 40, and the back encapsulation structure 50 encapsulate the cell string 30 to ensure that the photovoltaic module has high mechanical strength, reduce the impact of hail, wind, mechanical vibration, etc. on the photovoltaic module, improve the sealing performance of the photovoltaic module, and enhance its corrosion resistance and safety.

[0072] Specifically, the front encapsulation structure 10 and the back encapsulation structure 50 can be one of rigid materials such as tempered glass, polyethylene terephthalate (PET), and polycarbonate (PC), or one of flexible materials such as polyvinyl fluoride (PVF), ethylene-tetrafluoroethylene copolymer (ETFE), and polyvinylidene fluoride (PVDF). These materials have high light transmittance, which can improve the photoelectric conversion efficiency of the photovoltaic module and ensure the power output of the photovoltaic module. The front film layer 20 and the back film layer 40 can be one of the following materials: ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), polyvinyl butyral (PVB), EVA-POE-EVA co-extruded film (EPE), EVA-POE co-extruded film (EP).

[0073] The third aspect of this application provides a method for manufacturing a solar cell, applicable to the solar cells and photovoltaic modules described above.

[0074] The hole and electron concentrations inside a solar cell determine the charge state of hydrogen, which can be achieved by gaining and losing electrons, as shown in the following formula.

[0075]

[0076]

[0077]

[0078] In N-type substrate 1 solar cells, holes act as non-equilibrium carriers. form The reaction is enhanced, producing a large amount of... Negative charges can negatively impact minority carrier lifetime. Excessive accumulation can affect the passivation effect of solar cells, thereby impacting the passivation performance of the solar cells.

[0079] Figure 3 This is a flowchart of some embodiments of the method for manufacturing the solar cell involved in this application. For example... Figure 3 As shown, the method for manufacturing a solar cell includes:

[0080] S1: Print paste onto the battery cell and then dry and sinter it.

[0081] In this step, the slurry mainly consists of metal particles, glass frit, and a binder. First, it is dried at 100°C to 200°C to evaporate the organic solvents in the slurry. Then, a first-stage sintering is performed at 200°C to 400°C, during which the binder in the slurry is burned. A second-stage sintering is performed at 600°C to 900°C, during which the glass frit in the slurry melts and corrodes the solar cell, and the metal particles melt. Finally, cooling is performed, and the metal particles solidify to form the electrode. The metal particles can be one or more of silver, aluminum, nickel, and copper, or a composite thereof. In some other embodiments, the electrode can also be formed by electroplating.

[0082] S2: Set the battery cell to a first preset temperature and allow the first beam of light to irradiate the battery cell.

[0083] In this step, the solar cells are subjected to temperature and light to achieve the first photo-annealing, thereby reducing recombination centers in the solar cells.

[0084] The first passivation layer and the second passivation layer contain SiN. x H, primarily existing as Si-H and NH bonds, is generated during the first photo-annealing process. As photons from the first beam are injected into the solar cell and the temperature rises, numerous holes are created. The Si-H and NH bonds in the first and second passivation layers break, releasing H. This H diffuses into the first and second conductive structures, where it is converted into hydrogen under the influence of the holes. , By combining with recombination centers to form non-recombination centers, recombination in solar cells is reduced, thereby improving the open-circuit voltage, fill factor, and photoelectric conversion efficiency of solar cells.

[0085] S3: Set the battery cell to the second preset temperature and allow the second beam of light to irradiate the battery cell.

[0086] In this step, the solar cells are subjected to a second photo-annealing process by applying temperature and light to reduce the interface states of the solar cells.

[0087] During the second photo-annealing process, as the photons of the second beam are injected into the solar cell and the second preset temperature is applied, H continues to diffuse into the substrate 1. By reducing the density of Si dangling bonds, the interface states of the solar cell are reduced, the passivation effect is improved, and the annealing process of the solar cell is completed.

[0088] The second preset temperature is lower than the first preset temperature, thereby preventing damage to the solar cell under continuous high temperature.

[0089] In this embodiment, by performing two photo-annealing processes, recombination in the solar cell is reduced, the passivation effect of the solar cell is improved, and the photoelectric conversion efficiency of the solar cell is increased.

[0090] For example, through experiments, compared with solar cells that have undergone a second photo-annealing, the photoelectric conversion efficiency of solar cells that have undergone a second photo-annealing is increased by 0.1% to 0.15%, the open-circuit voltage is increased by 0.5 to 1.5 mV, the fill factor is increased by 0.2 to 0.5, and the photoluminescence brightness is increased by 600 to 1000.

[0091] In some embodiments, the first preset temperature T1 satisfies: 600℃ ≤ T1 ≤ 700℃. For example, the first preset temperature T1 can specifically be 600℃, 601℃, 602℃, 605℃, 608℃, 610℃, 615℃, 620℃, 625℃, 630℃, 635℃, 640℃, 645℃, 650℃, 655℃, 660℃, 665℃, 670℃, 675℃, 680℃, 685℃, 690℃, 695℃, 698℃, 699℃, 700℃, etc. It is understood that the first preset temperature T1 can also be a value other than those listed above.

[0092] The value of the first preset temperature T1 should not be too high or too low. If the value of the first preset temperature T1 is too high (for example, greater than 700℃), it will easily damage the solar cell. If the value of the first preset temperature T1 is too low (for example, less than 600℃), the H generated during the first photo-annealing process will be smaller, and fewer recombination centers will be consumed, which is not conducive to reducing the recombination of the solar cell.

[0093] Therefore, the first preset temperature T1 should be set within a suitable range to generate more H without damaging the solar cell.

[0094] In some embodiments, the second preset temperature T2 satisfies: 100℃ ≤ T2 ≤ 200℃. For example, the second preset temperature T2 can specifically be 100℃, 101℃, 102℃, 105℃, 108℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 192℃, 195℃, 198℃, 199℃, 200℃, etc. It is understood that the second preset temperature T2 can also be a value other than those listed above.

[0095] The value of the second preset temperature T2 should not be too large or too small. If the value of the second preset temperature T2 is too large (for example, greater than 200°C), it will not be conducive to the temperature reduction of the cell after the first photo-annealing, and may still cause damage to the solar cell. If the value of the second preset temperature T2 is too small (for example, less than 100°C), it will not be conducive to reducing the density of Si dangling bonds, and will affect the passivation effect.

[0096] Therefore, the second preset temperature T2 should be set within a suitable range.

[0097] In some embodiments, the wavelength of the first beam is equal to the wavelength of the second beam. Therefore, the same light source can be used for both the first and second photo-annealing stages, which simplifies the structure of the processing module for the first and second photo-annealing of solar cells. Furthermore, since the light source does not need to be changed, the second photo-annealing can be performed as soon as possible after the first photo-annealing, thus improving the production efficiency of solar cells.

[0098] In some other embodiments, the wavelengths of the first beam and the second beam may also be different.

[0099] In some embodiments, the wavelength of the first beam satisfies the range of 400nm to 800nm. For example, the wavelength of the first beam can specifically be 400nm, 410nm, 420nm, 430nm, 4500nm, 480nm, 500nm, 520nm, 550nm, 580nm, 600nm, 620nm, 650nm, 680nm, 700nm, 720nm, 750nm, 780nm, 790nm, 800nm, etc. It is understood that the wavelength of the first beam can also be a value other than those listed above.

[0100] The wavelength of the first beam should not be too short or too long. If the wavelength of the first beam is too short (e.g., less than 400 nm), the photon energy of the first beam will be too high, which will easily damage the solar cell and generate new defects. If the wavelength of the first beam is too short (e.g., longer than 800 nm), the photon energy of the first beam will be too low and will not be able to provide enough energy to generate H.

[0101] Therefore, the wavelength of the first beam should be set within an appropriate range.

[0102] In one specific embodiment, the wavelength of the first beam is 600 nm.

[0103] In some embodiments, the wavelength of the second beam satisfies the range of 400nm to 800nm. For example, the specific wavelength of the second beam can be 400nm, 410nm, 420nm, 430nm, 4500nm, 480nm, 500nm, 520nm, 550nm, 580nm, 600nm, 620nm, 650nm, 680nm, 700nm, 720nm, 750nm, 780nm, 790nm, 800nm, etc. It is understood that the wavelength of the second beam can also be a value other than those listed above.

[0104] The wavelength of the second beam should not be too short or too long. If the wavelength of the second beam is too short (e.g., less than 400 nm), the photon energy of the second beam will be too high, which will easily damage the solar cell and generate new defects. If the wavelength of the second beam is too short (e.g., longer than 800 nm), the photon energy of the second beam will be too low and will not be able to provide enough energy to generate H.

[0105] Therefore, the wavelength of the second beam should be set within an appropriate range.

[0106] In one specific embodiment, the wavelength of the second beam is 600 nm.

[0107] In some embodiments, the time t1 for the first beam to irradiate the solar cell satisfies: 8s ≤ t1 ≤ 14s. For example, the specific time t1 for the first beam to irradiate the solar cell can be: 8s, 8s30′, 9s, 9s30′, 10s, 10s30′, 11s, 11s30′, 12s, 12s30′, 13s, 13s30′, 14s, etc. It is understood that the time t1 for the first beam to irradiate the solar cell can also be a value other than those mentioned above.

[0108] The duration t1 for the first beam to irradiate the solar cell should not be too short or too long. If the duration t1 is too short (e.g., less than 8s), sufficient generation H cannot be generated to reduce recombination centers. If the duration t1 is too long (e.g., more than 14s), the heat accumulated by the light may burn the solar cell.

[0109] Therefore, the time t1 for the first beam to irradiate the solar cell should be set within an appropriate range.

[0110] In some embodiments, the time t2 during which the second beam irradiates the solar cell satisfies: 15s ≤ t2 ≤ 30s. For example, the specific time t2 during which the second beam irradiates the solar cell can be: 15s, 15s30′, 16s, 16s30′, 17s, 17s30′, 18s, 18s30′, 19s, 19s30′, 20s, 21s, 22s, 23s, 24s, 25s, 25s30′, 26s, 26s30′, 27s, 27s30′, 28s, 28s30′, 29s, 29s30′, 30s, etc. The time t2 during which the second beam irradiates the solar cell can also be a value other than those mentioned above.

[0111] The time t2 for the second beam to irradiate the solar cell should not be too short or too long. If the time t2 for the second beam to irradiate the solar cell is too short (e.g., less than 15s), it will not be conducive to reducing the density of Si dangling bonds and will affect the passivation effect. If the time t2 for the second beam to irradiate the solar cell is too long (e.g., more than 30s), it will prolong the production time of the solar cell and reduce the production efficiency of the solar cell.

[0112] Therefore, the time t2 for the second beam to irradiate the solar cell should be set within an appropriate range.

[0113] In the above embodiments, the method for manufacturing a solar cell further includes:

[0114] S4: Provides base 1.

[0115] Figure 4 A schematic diagram of the structure of the solar cell involved in this step is shown.

[0116] In this step, the substrate 1 is polished to optimize its surface condition, remove the surface damage layer, and provide a good foundation for subsequent processes.

[0117] S5: A first conductive structure is formed on the surface of substrate 1.

[0118] Figure 5 A schematic diagram of the structure of the solar cell involved in this step is shown.

[0119] In this step, an oxide layer and a polycrystalline silicon layer are first formed on the surface of substrate 1. Then, boron or phosphorus diffusion is performed on the polycrystalline silicon layer to form a doped polycrystalline silicon layer. The oxide layer serves as the first tunneling layer 2, and the doped polycrystalline silicon layer serves as the first doped conductive layer 3. Simultaneously, during the formation of the doped polycrystalline silicon layer, a first glass layer (not shown in the figure) is formed on the outermost side of the solar cell.

[0120] Taking boron diffusion as an example, boron sources can be deposited through ion implantation, spin coating, low-pressure chemical vapor deposition (LPCVD), or plasma-enhanced chemical vapor deposition (PECVD). Boron precursors include, but are not limited to, boron chloride (BCl3), boron bromide (BBr3), trimethylboron (C3H9B), and boron-containing slurries.

[0121] S6: Laser etching of the first conductive structure located on the second side 12, excluding the first region a.

[0122] Figure 6 A schematic diagram of the structure of the solar cell involved in this step is shown.

[0123] In this step, selective laser etching exposes the portion of the substrate 1 on the second side 12, excluding the first region a.

[0124] Optionally, after laser etching, the portion of the second side 12 excluding the first region a can be etched with an alkaline solvent to remove the damage caused to the substrate 1 by laser etching. During this process, the first glass layer can protect the portion of the first region a.

[0125] S7: A second conductive structure is formed on the outside of the substrate 1 and the first conductive structure.

[0126] Figure 7 A schematic diagram of the structure of the solar cell involved in this step is shown.

[0127] In this step, an oxide layer and a polycrystalline silicon layer are first formed on the outer side of the substrate 1 and the first conductive structure. Then, phosphorus diffusion or boron diffusion is performed on the polycrystalline silicon layer to form a doped polycrystalline silicon layer. The oxide layer serves as the second tunneling layer 4, and the doped polycrystalline silicon layer serves as the second doped conductive layer 5. Simultaneously, during the formation of the doped polycrystalline silicon layer, a second glass layer (not shown in the figure) is formed around the outermost edge of the solar cell.

[0128] Taking phosphorus diffusion as an example, phosphorus sources can be deposited through ion implantation, swirl coating, low-pressure chemical vapor deposition (LPCVD), or plasma-enhanced chemical vapor deposition (PECVD). Phosphorus precursors include, but are not limited to, phosphine (PH3), phosphorus oxychloride (POCl3), phosphoric acid (H3PO4), or phosphorus-containing slurries.

[0129] S8: Laser etching of the second conductive structure located on the second side 12, excluding the second region b.

[0130] Figure 8 A schematic diagram of the structure of the solar cell involved in this step is shown.

[0131] In this step, by selectively etching with a laser, the second conductive structure located in the first region a is removed on the one hand, and a gap, namely the spacer region c, is created between the first conductive structure located in the first region a and the second conductive structure located in the second region b.

[0132] S9: Etch the first conductive structure and the second conductive structure located on the first side 11.

[0133] Figure 9 A schematic diagram of the structure of the solar cell involved in this step is shown.

[0134] In this step, the substrate is exposed on the first side 11 and the portions on both sides by etching.

[0135] S10: Texturing the solar cells.

[0136] In this step, the front side and the spacer area c of the solar cell form an undulating, uneven textured surface to reduce the reflection of sunlight by the manufactured solar cell, increase the absorption rate of sunlight by the manufactured solar cell, and thus improve the photoelectric conversion efficiency of the solar cell.

[0137] S11: An aluminum oxide layer 6 is formed on the first side 11 and the second side 12, a silicon oxide layer 8 and a silicon nitride layer 7 are formed on the first side 11, and a silicon nitride layer 7 is formed on the second side 12.

[0138] In this step, such as Figure 1 As shown, a first passivation layer and a second passivation layer are formed.

[0139] Optionally, the thickness of the aluminum oxide layer 6 can be 3 nm, the thickness of the silicon oxide layer 8 can be 100 nm, the thickness of the silicon nitride layer 7 located on the first side 11 can be 50 nm, and the thickness of the silicon nitride layer 7 located on the second side 12 can be 80 nm, that is, the thickness of the silicon nitride layer 7 located on the second side 12 is greater than the thickness of the silicon nitride layer 7 located on the first side 11.

[0140] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for manufacturing a solar cell, characterized in that, The solar cell has a substrate, a first conductive structure, a second conductive structure, a first passivation layer, and a second passivation layer, wherein the substrate has an N-type dopant element; The method for manufacturing the solar cell includes: The paste is printed onto the battery cells, which are then dried and sintered. The battery cell is brought to a first preset temperature, and a first light beam is used to irradiate the battery cell. The first passivation layer and the second passivation layer release H. The H released by the first passivation layer diffuses into the first conductive structure, and the H released by the second passivation layer diffuses into the second conductive structure. The battery cell is brought to a second preset temperature, and a second light beam is used to irradiate the battery cell, causing the H released by the first passivation layer and the second passivation layer to diffuse into the substrate; Wherein, the second preset temperature is lower than the first preset temperature; the first preset temperature T1 satisfies: 600℃≤T1≤700℃.

2. The method for manufacturing a solar cell according to claim 1, characterized in that, The second preset temperature T2 satisfies: 100℃≤T2≤200℃.

3. The method for manufacturing a solar cell according to claim 1, characterized in that, The wavelength of the first beam is equal to the wavelength of the second beam.

4. The method for manufacturing a solar cell according to claim 3, characterized in that, The wavelength of the first beam satisfies: 400nm~800nm.

5. The method for manufacturing a solar cell according to claim 1, characterized in that, The duration t1 for which the first beam illuminates the solar cell satisfies: 8s ≤ t1 ≤ 14s.

6. The method for manufacturing a solar cell according to claim 1, characterized in that, The duration t2 during which the second beam illuminates the solar cell satisfies: 15s ≤ t2 ≤ 30s.

7. The method for manufacturing a solar cell according to any one of claims 1-6, characterized in that, The battery cell has a first side (11) and a second side (12) opposite each other. Before the steps of printing paste onto the solar cell and drying / sintering, the method for manufacturing the solar cell includes: An aluminum oxide layer (6) is formed on the first side (11) and the second side (12). A silicon oxide layer (8) and a silicon nitride layer (7) are formed on the first side (11), and a silicon nitride layer (7) is formed on the second side (12).

8. The method for manufacturing a solar cell according to claim 7, characterized in that, The second side (12) has a first region (a) and a second region (b), the first region (a) is provided with a first conductive structure, and the second region (b) is provided with a second conductive structure, the polarities of the first conductive structure and the second conductive structure are different; Before the steps of forming a silicon oxide layer (8) and a silicon nitride layer (7) on the first side (11) and forming a silicon nitride layer (7) on the second side (12), the method for manufacturing the solar cell further includes: The first conductive structure is formed in the first region (a), and the second conductive structure is formed in the second region (b); The solar cell is texturized.

9. The method for manufacturing a solar cell according to claim 8, characterized in that, Steps: Forming the first conductive structure in the first region (a) and forming the second conductive structure in the second region (b) include: Provide a substrate (1); A first conductive structure is formed on the surface of the substrate (1); Laser etching is performed on the first conductive structure located on the second side (12), excluding the first region (a); A second conductive structure is formed on the outside of the substrate (1) and the first conductive structure; Laser etching is performed on the second conductive structure located on the second side (12), excluding the second region (b); The first conductive structure and the second conductive structure located on the first side (11) are etched.

10. A solar cell, characterized in that, The solar cell is manufactured by the method of manufacturing a solar cell according to any one of claims 1-9.

11. A photovoltaic module, characterized in that, The photovoltaic module includes the solar cell of claim 10.

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