Solar cell hydrogen passivation method and application thereof

Abstract

The application discloses a hydrogen passivation method for a solar cell and application thereof, and belongs to the technical field of solar cells. The method comprises at least twice hydrogen passivation, at least once of which is carried out before printing after a back film and at least once of which is carried out after sintering before printing after the back film. Light injection hydrogen passivation is carried out before printing after the back film, hydrogen atoms in a silicon nitride passivation film are activated by temperature rising, then the valence state of the hydrogen atoms is controlled by light irradiation, so that the hydrogen atoms are combined with a P emitter and an N-type base and a recombination center (a defect) to form a non-recombination center, a preliminary passivation effect is achieved, then secondary hydrogen passivation is carried out by electric injection or light injection after printing and sintering, damage caused by a sintering high-temperature process to passivation effect of a cell piece can be repaired to the maximum extent, the adverse effect of a sintering procedure on hydrogen passivation is improved, the conversion efficiency of the cell piece is improved, and the light-induced degradation resistance is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of solar cells, and specifically relates to a hydrogen passivation method for solar cells and its application. Background Art

[0002] In recent years, driven by clean energy policies, the photovoltaic industry has flourished globally. However, the development of photovoltaic technology still faces two major challenges: reducing costs and improving conversion efficiency. Solar cells, particularly polycrystalline silicon cells, are severely hampered by the presence of numerous metallic impurities and defects in the polycrystalline silicon, which severely hinders the improvement of photovoltaic conversion efficiency. To achieve high-quality solar cells, hydrogen atoms are often introduced to passivate the crystalline impurities and defects on the surface and in the bulk of the solar cell.

[0003] In the prior art, hydrogen passivation of solar cells often involves a single optical or electrical hydrogen injection passivation of the solar cell after the back film (silicon nitride film) is formed, printed, and sintered. The hydrogen atoms rich in the silicon nitride film diffuse to the interface of the silicon crystal, passivating the silicon dangling bonds on the interface and reducing the surface recombination rate of the silicon crystal. For example, Chinese invention patent application publication number CN114050206A describes a solar cell and its hydrogen passivation method, specifically disclosing: forming a first passivation layer (aluminum oxide layer and silicon nitride layer) containing hydrogen and a second passivation layer containing hydrogen on the front and back sides of a silicon substrate, respectively; printing electrodes on the surface of the first passivation layer away from the diffusion layer and the surface of the second passivation layer away from the doped polysilicon layer, respectively, and sintering them to obtain a prefabricated solar cell including a metallized hydrogen passivation layer; annealing the prefabricated solar cell in a predetermined manner to obtain an annealed solar cell; and performing a light-induced treatment on the annealed solar cell to obtain a hydrogen-passivated solar cell.

[0004] However, during the sintering process, the corrosive silver paste will burn through the silicon nitride layer and the aluminum oxide layer, making its passivation effect on carriers worse. In addition, a certain amount of hydrogen atoms will escape from the silicon wafer during the sintering process, weakening the passivation effect of hydrogen on the silicon wafer. It also causes the hydrogen passivation to fail to fully activate the hydrogen atoms to achieve the ideal passivation effect.

[0005] Therefore, it is necessary to improve the existing process, reduce the adverse effects of sintering on the hydrogen passivation effect, and improve the hydrogen passivation effect. Summary of the Invention

[0006] 1. Problem to be solved

[0007] In response to the adverse effects of the sintering process on hydrogen passivation of solar cells in the prior art, the present application provides a method for hydrogen passivation of solar cells and its application, comprising at least two hydrogen passivations, at least one of which is performed before printing and at least one after sintering. A preliminary passivation effect is achieved by performing hydrogen passivation before printing, and a secondary passivation is performed after sintering, thereby achieving the purpose of improving the conversion efficiency of the cell and enhancing the resistance to light-induced degradation.

[0008] 2. Technical solution

[0009] In order to solve the above problems, the technical solutions adopted in this application are as follows:

[0010] As a first aspect of the present application, the present application provides a method for hydrogen passivation of solar cells, which includes at least two hydrogen passivation steps, at least one of which is performed before printing and at least one is performed after sintering.

[0011] Furthermore, the above-mentioned method for hydrogen passivation of solar cells includes two hydrogen passivations, one before printing and one after sintering.

[0012] Furthermore, the hydrogen passivation before the above-mentioned printing adopts light injection hydrogen passivation. Light injection hydrogen passivation refers to the use of high-intensity visible light to irradiate solar cells at a certain temperature, which can improve the efficiency of hydrogen passivation and defect repair, thereby reducing the battery attenuation effect and improving efficiency.

[0013] Furthermore, the hydrogen passivation after the above sintering adopts electric injection hydrogen passivation or light injection hydrogen passivation. Electric injection hydrogen passivation means that under appropriate temperature conditions, a certain current is continuously passed through the solar cell to achieve the passivation effect, which can significantly improve the efficiency and anti-light decay ability of the cell. After sintering, the grid line has been formed, so electric injection can be performed.

[0014] Furthermore, the hydrogen passivation before printing and after sintering can adopt the same hydrogen passivation method, that is, the hydrogen passivation after sintering adopts light injection hydrogen passivation.

[0015] Furthermore, the hydrogen passivation before printing and after sintering can adopt different hydrogen passivation methods, that is, the hydrogen passivation after sintering adopts electric injection hydrogen passivation.

[0016] Furthermore, the above-mentioned optical injection hydrogen passivation before printing includes two steps: illumination and heat preservation, wherein the temperature T2 of the heat preservation step is lower than the temperature T1 of the illumination step, so that slow cooling can be achieved.

[0017] Furthermore, the temperature difference between T1 and T2 is 300-600°C.

[0018] Furthermore, the light-injected hydrogen passivation before printing includes: irradiating and heat-insulating the solar cell behind the back film, wherein the heat-insulating temperature T2 is lower than the irradiation temperature T1, so that slow cooling can be achieved.

[0019] Furthermore, the illumination intensity of the illumination is 20 to 40 suns. Still further, the illumination intensity of the illumination is 40 suns.

[0020] Furthermore, the light source of the above illumination is an infrared light source or an LED light source.

[0021] Furthermore, the light source of the illumination is an LED light source, and the LED light source includes an LED lamp with a light intensity of 10 to 50 suns.

[0022] Furthermore, the LED light source includes an LED lamp with a light intensity of 20 to 40 suns. Still further, the LED light source includes an LED lamp with a light intensity of 40 suns.

[0023] Furthermore, the illumination temperature T1 of the illumination is 500-700° C., and the illumination time is 5-20 seconds. Still further, the illumination temperature T1 of the illumination is 500-700° C., and the illumination time is 8 seconds.

[0024] Furthermore, the holding temperature T2 of the heat preservation is 100-200° C., and the holding time is 5-10 seconds. Furthermore, the holding temperature T2 of the heat preservation is 100-200° C., and the holding time is 10 seconds.

[0025] Furthermore, the light-implanted hydrogen passivation after sintering includes two steps: illumination and heat preservation, wherein the temperature T4 of the heat preservation step is lower than the temperature T3 of the illumination step, and T3≤T1.

[0026] Furthermore, the temperature difference between T3 and T4 is 300-550°C.

[0027] Furthermore, the temperature difference between T1 and T3 is 0-50°C.

[0028] Furthermore, the light-injected hydrogen passivation after sintering includes: irradiating and heat-insulating the sintered solar cell, wherein the heat-insulating temperature T4 is lower than the irradiation temperature T3, and T3≤T1.

[0029] Furthermore, the illumination intensity of the illumination is 20 to 40 suns. Still further, the illumination intensity of the illumination is 40 suns.

[0030] Furthermore, the light source of the above illumination is an infrared light source or an LED light source.

[0031] Furthermore, the light source of the illumination is an LED light source, and the LED light source includes an LED lamp with a light intensity of 10 to 50 suns.

[0032] Furthermore, the LED light source includes an LED lamp with a light intensity of 20 to 40 suns. Still further, the LED light source includes an LED lamp with a light intensity of 40 suns.

[0033] Furthermore, the illumination temperature T3 of the illumination is 500-650° C., and the illumination time is 5-10 seconds. Furthermore, the illumination temperature T3 of the illumination is 500-650° C., and the illumination time is 8 seconds.

[0034] Furthermore, the heat preservation temperature T4 of the heat preservation is 100-200° C., and the light exposure time is 5-10 seconds. Furthermore, the heat preservation temperature T4 of the heat preservation is 100-200° C., and the heat preservation time is 8 seconds.

[0035] Furthermore, the above-mentioned electric injection of hydrogen passivation after sintering includes: performing electric injection of hydrogen passivation on the sintered solar cell.

[0036] Furthermore, the heating temperature for the above-mentioned hydrogen injection passivation is 100-250°C, the current intensity is 2-10A, and the injection time is 400-2000s. For hydrogen injection passivation, if the applied current is too high, it will change the charging properties of the hydrogen element, thereby reducing the bulk passivation effect of the crystalline silicon solar cell. Therefore, it is necessary to select an appropriate current.

[0037] Furthermore, the time of the above-mentioned electrical injection is 1800s.

[0038] Furthermore, the above-mentioned method for hydrogen passivation of a solar cell comprises:

[0039] Performing photo-injection hydrogen passivation on the solar cells behind the back film;

[0040] Screen printing of solar cells passivated by photoinjection of hydrogen;

[0041] Sintering the screen-printed solar cells;

[0042] The sintered solar cell is subjected to electric injection hydrogen passivation or light injection hydrogen passivation.

[0043] Furthermore, the sintering includes drying and sintering.

[0044] Furthermore, the drying temperature is 200-350° C., and the drying time is 3-5 seconds.

[0045] Furthermore, the sintering temperature is 500-850° C., and the sintering time is 10-20 seconds. Furthermore, the sintering time is 12 seconds.

[0046] As a second aspect of the present application, the present application also provides an application of the above-mentioned solar cell hydrogen passivation method in the preparation of solar cells.

[0047] Furthermore, the above application also includes the following steps before the solar cell behind the back film is subjected to light injection hydrogen passivation: texturing, diffusion, etching, back film and the like.

[0048] As a third aspect of the present application, the present application further provides a method for preparing a solar cell, which includes the above-mentioned hydrogen passivation method for a solar cell.

[0049] Furthermore, the above-mentioned solar cell preparation method includes: texturing, diffusion, etching, back film, light injection hydrogen passivation of the solar cell after back film, screen printing, sintering, and electric injection hydrogen passivation or light injection hydrogen passivation of the sintered solar cell.

[0050] As a fourth aspect of the present application, the present application also provides a solar cell prepared by a solar cell preparation method comprising the above-mentioned solar cell hydrogen passivation method.

[0051] 3. Beneficial effects

[0052] Compared with the prior art, the present application has the following advantages:

[0053] The present application provides a method for hydrogen passivation of solar cells and its application, which involves at least two hydrogen passivations, at least one of which is performed before printing and at least one after sintering, and light injection hydrogen passivation is performed after the back film and before printing. The hydrogen atoms in the silicon nitride passivation film are activated by heating, and then the valence state of the hydrogen atoms is controlled by light so that they combine with recombination centers (defects) at the P emitter and the N-type substrate to form non-recombination centers, thereby achieving a preliminary passivation effect. Then, after printing and sintering, electrical injection or light injection is performed for secondary hydrogen passivation, which can repair the damage to the passivation effect of the cell caused by the high-temperature sintering process to the greatest extent, and improve the adverse effects of the sintering process on hydrogen passivation. At the same time, adding a heat preservation step during the light injection hydrogen passivation process can further improve the effect of hydrogen passivation, improve the conversion efficiency of the cell, and improve the resistance to light-induced degradation. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a flow chart of a solar cell hydrogen passivation method of the present application. DETAILED DESCRIPTION

[0055] The present application is further described below with reference to specific embodiments.

[0056] It should be noted that the terms such as "upper", "lower", "left", "right", and "middle" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of this application without substantially changing the technical content.

[0057] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0058] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0059] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement, or value. One skilled in the art can readily determine the degree of flexibility for a particular variable.

[0060] As used herein, the term "at least one of" is intended to be synonymous with "one or more of." For example, "at least one of A, B, and C" explicitly includes only A, only B, only C, and combinations of each thereof.

[0061] Concentration, amount and other numerical data can be presented in range format in this article.Should be understood that such range format is only used for convenience and brevity, and should be flexibly interpreted as not only including the numerical value clearly described as range limit, but also including all independent numerical values ​​or subranges encompassed within the scope, just as each numerical value and subrange are clearly described.For example, the numerical range of about 1 to about 4.5 should be interpreted as not only including the limit value of 1 to about 4.5 clearly described, but also including independent numerals (such as 2,3,4) and subranges (such as 1 to 3,2 to 4 etc.).The same principle is applicable to the scope of only narrating a numerical value, such as "less than about 4.5", which should be interpreted as including all above-mentioned values ​​and scopes.In addition, no matter how the breadth of described scope or feature is, this explanation should be applicable.

[0062] In this application, the preparation of solar cells after the back film includes:

[0063] Texturing of silicon wafers;

[0064] Deposit and diffuse boron on silicon wafers;

[0065] Remove PSG and perform alkaline polishing on silicon wafers;

[0066] Depositing a tunnel oxide layer and a polysilicon layer on a silicon wafer;

[0067] Deposition and diffusion of phosphorus elements on silicon wafers;

[0068] Remove PSG and RCA from silicon wafers;

[0069] Coating aluminum oxide film and anti-reflection film on silicon wafers;

[0070] Photo-implanted hydrogen passivation;

[0071] Screen printing on silicon wafers;

[0072] sintering;

[0073] Photo-injection / electrical-injection hydrogen passivation.

[0074] Example 1

[0075] This embodiment provides a solar cell hydrogen passivation method and its application. The solar cell hydrogen passivation method includes two hydrogen passivations, one before printing and one after sintering. The hydrogen passivation before printing is light injection hydrogen passivation, and the hydrogen passivation after sintering is electric injection hydrogen passivation. Specifically, the method includes:

[0076] (1) Photoinjection hydrogen passivation of solar cells behind the back film

[0077] The solar cell behind the back film is illuminated and kept warm. First, it is preheated by using an LED lamp with a light intensity of 20 to 40 suns. The light intensity is 40 suns, the belt speed is 16m / min, the temperature is 500 to 700℃, and the time is 8s. Then it is kept warm with the temperature set at 100 to 200℃ for 10s.

[0078] (2) Screen printing of solar cells after light-injected hydrogen passivation

[0079] Printing speed: 550mm / s, printing pressure: 55N, printing height: 2mm.

[0080] (3) Sintering the screen-printed solar cells

[0081] Sintering includes drying and sintering. The drying temperature is 200-350° C. and the time is 3-5 seconds. The sintering temperature is 500-850° C. and the time is 12 seconds. The belt conveying speed is 16 m / min.

[0082] (4) Passivation of sintered solar cells by electric injection of hydrogen

[0083] The heating temperature of the electric injection is 100-250° C., the current intensity is 2-10 A, and the time is 1800 s.

[0084] (5) Cooling to room temperature to obtain a solar cell.

[0085] Example 2

[0086] This embodiment provides a solar cell hydrogen passivation method and its application. The solar cell hydrogen passivation method includes two hydrogen passivations, one before printing and one after sintering. The hydrogen passivation before printing is light-injected hydrogen passivation, and the hydrogen passivation after sintering is light-injected hydrogen passivation. Specifically, the method includes:

[0087] (1) Photoinjection hydrogen passivation of solar cells behind the back film

[0088] The solar cell behind the back film is illuminated and kept warm. First, it is preheated by using an LED lamp with a light intensity of 20 to 40 suns. The light intensity is 40 suns, the belt speed is 16m / min, the temperature is 500 to 700℃, and the time is 8s. Then it is kept warm with the temperature set at 100 to 200℃ for 10s.

[0089] (2) Screen printing of solar cells after light-injected hydrogen passivation

[0090] Printing speed: 550mm / s, printing pressure: 55N, printing height: 2mm.

[0091] (3) Sintering the screen-printed solar cells

[0092] Sintering includes drying and sintering. The drying temperature is 200-350° C. and the time is 3-5 seconds. The sintering temperature is 500-850° C. and the time is 12 seconds. The belt conveying speed is 16 m / min.

[0093] (4) Photoinjection hydrogen passivation of sintered solar cells

[0094] The sintered solar cells are illuminated and kept warm using LED lights with a light intensity of 40 suns, a belt speed of 16 m / min, a temperature of 500-650°C, and a time of 8 seconds; then a heat preservation treatment is performed with a temperature set at 100-200°C and a time of 8 seconds.

[0095] (5) Cooling to room temperature to obtain a solar cell.

[0096] Comparative Example 1

[0097] This embodiment provides a method for hydrogen passivation of solar cells and its application. The method for hydrogen passivation of solar cells includes a primary hydrogen passivation process, i.e., a light-injection hydrogen passivation process after sintering, specifically including:

[0098] (1) Screen printing of solar cells behind the back film

[0099] Printing speed: 550mm / s, printing pressure: 55N, printing height: 2mm.

[0100] (2) Sintering the screen-printed solar cells

[0101] Sintering includes drying and sintering. The drying temperature is 200-350° C. and the time is 3-5 seconds. The sintering temperature is 500-850° C. and the time is 12 seconds. The belt conveying speed is 16 m / min.

[0102] (3) Photoinjection hydrogen passivation of sintered solar cells

[0103] The sintered solar cells are illuminated and kept warm using LED lights with a light intensity of 40 suns, a belt speed of 16 m / min, a temperature of 500-650°C, and a time of 8 seconds; then a heat preservation treatment is performed with a temperature set at 100-200°C and a time of 8 seconds.

[0104] (4) Cooling to room temperature to obtain a solar cell.

[0105] Comparative Example 2

[0106] This embodiment provides a method for hydrogen passivation of solar cells and its application. The method for hydrogen passivation of solar cells includes a primary hydrogen passivation, i.e., a light-injection hydrogen passivation treatment before sintering, specifically including:

[0107] (1) Photoinjection hydrogen passivation of solar cells behind the back film

[0108] The solar cell behind the back film is illuminated and kept warm. First, it is preheated by using an LED lamp with a light intensity of 20 to 40 suns. The light intensity is 40 suns, the belt speed is 16m / min, the temperature is 500 to 700℃, and the time is 8s. Then it is kept warm with the temperature set at 100 to 200℃ for 10s.

[0109] (2) Screen printing of solar cells before screen printing

[0110] Printing speed: 550mm / s, printing pressure: 55N, printing height: 2mm.

[0111] (3) Sintering of solar cells passivated by light-injected hydrogen

[0112] Sintering includes drying and sintering. The drying temperature is 200-350° C. and the time is 3-5 seconds. The sintering temperature is 500-850° C. and the time is 12 seconds. The belt conveying speed is 16 m / min.

[0113] (4) Cooling to room temperature to obtain a solar cell.

[0114] Comparative Example 3

[0115] This embodiment provides a solar cell hydrogen passivation method and its application. The solar cell hydrogen passivation method includes two hydrogen passivations, one before printing and one after sintering. The hydrogen passivation before printing is light injection hydrogen passivation, and the hydrogen passivation after sintering is electric injection hydrogen passivation. The difference from Example 1 is that the light injection hydrogen passivation process does not include heat preservation. Specifically, it includes:

[0116] (1) Photoinjection hydrogen passivation of solar cells behind the back film

[0117] The solar cell behind the back film is illuminated and kept warm. First, it is preheated by using an LED light with a light intensity of 20 to 40 suns. The light intensity is 40 suns, the belt speed is 16 m / min, the temperature is 500 to 700 ° C, and the time is 8 seconds.

[0118] (2) Screen printing of solar cells after light-injected hydrogen passivation

[0119] Printing speed: 550mm / s, printing pressure: 55N, printing height: 2mm.

[0120] (3) Sintering the screen-printed solar cells

[0121] Sintering includes drying and sintering. The drying temperature is 200-350° C. and the time is 3-5 seconds. The sintering temperature is 500-850° C. and the time is 12 seconds. The belt conveying speed is 16 m / min.

[0122] (4) Passivation of sintered solar cells by electric injection of hydrogen

[0123] The heating temperature of the electric injection is 100-250° C., the current intensity is 2-10 A, and the time is 1800 s.

[0124] (5) Cooling to room temperature to obtain a solar cell.

[0125] Comparative Example 4

[0126] This embodiment provides a solar cell hydrogen passivation method and its application. The solar cell hydrogen passivation method includes two hydrogen passivations, one before printing and one after sintering. The hydrogen passivation before printing is light-injected hydrogen passivation, and the hydrogen passivation after sintering is light-injected hydrogen passivation. The difference from Example 2 is that the light-injected hydrogen passivation process does not include heat preservation. Specifically, it includes:

[0127] (1) Photoinjection hydrogen passivation of solar cells behind the back film

[0128] The solar cell behind the back film is illuminated and preheated by using an LED light with a light intensity of 20 to 40 suns, a light intensity of 40 suns, a belt speed of 16 m / min, a temperature of 500 to 700°C, and a time of 8 seconds.

[0129] (2) Screen printing of solar cells after light-injected hydrogen passivation

[0130] Printing speed: 550mm / s, printing pressure: 55N, printing height: 2mm.

[0131] (3) Sintering the screen-printed solar cells

[0132] Sintering includes drying and sintering. The drying temperature is 200-350° C. and the time is 3-5 seconds. The sintering temperature is 500-850° C. and the time is 12 seconds. The belt conveying speed is 16 m / min.

[0133] (4) Photoinjection hydrogen passivation of sintered solar cells

[0134] The sintered solar cells are illuminated and kept warm using LED lights with a light intensity of 40 suns, a belt speed of 16 m / min, a temperature of 500-650° C., and a time of 8 seconds.

[0135] (5) Cooling to room temperature to obtain a solar cell.

[0136] Comparative Example 5

[0137] This embodiment provides a solar cell hydrogen passivation method and its application. The solar cell hydrogen passivation method includes two hydrogen passivations, one before printing and one after sintering. The hydrogen passivation before printing is light-injected hydrogen passivation, and the hydrogen passivation after sintering is light-injected hydrogen passivation. The difference from Example 2 is that the illumination temperature of the light-injected hydrogen passivation after sintering is higher than the illumination temperature of the light-injected hydrogen passivation before printing. Specifically, the method includes:

[0138] (1) Photoinjection hydrogen passivation of solar cells behind the back film

[0139] The solar cell behind the back film is illuminated and kept warm. First, it is preheated by using an LED lamp with a light intensity of 20 to 40 suns. The light intensity is 40 suns, the belt speed is 16m / min, the temperature is 500 to 700℃, and the time is 8s. Then it is kept warm with the temperature set at 100 to 200℃ for 10s.

[0140] (2) Screen printing of solar cells after light-injected hydrogen passivation

[0141] Printing speed: 550mm / s, printing pressure: 55N, printing height: 2mm.

[0142] (3) Sintering the screen-printed solar cells

[0143] Sintering includes drying and sintering. The drying temperature is 200-350° C. and the time is 3-5 seconds. The sintering temperature is 500-850° C. and the time is 12 seconds. The belt conveying speed is 16 m / min.

[0144] (4) Photoinjection hydrogen passivation of sintered solar cells

[0145] The sintered solar cells were illuminated and kept warm using LED lights with a light intensity of 40 suns, a belt speed of 16 m / min, a temperature of 750°C, and a time of 8 seconds; then the solar cells were kept warm with a temperature set at 100-200°C and a time of 8 seconds.

[0146] (5) Cooling to room temperature to obtain a solar cell.

[0147] Example 3

[0148] The test results of the solar cells prepared in Examples 1-2 and Comparative Examples 1-5 are shown in Table 1.

[0149] Table 1

[0150] Eta (%) Uoc(mV) Isc(A) FF(%) yield Example 1 24.83 709.78 13.98 83.75 96.2％ Example 2 24.76 708.69 14.02 83.56 95.8％ Comparative Example 1 24.63 706.47 14.00 83.30 94.0％ Comparative Example 2 24.36 703.63 13.98 82.55 73.8％ Comparative Example 3 24.28 702.86 13.88 82.35 70.9％ Comparative Example 4 24.78 709.66 13.95 83.62 94.6％ Comparative Example 5 24.69 708.48 13.98 83.59 93.6％

[0151] in:

[0152] Eta is the battery conversion rate, also known as photoelectric conversion efficiency;

[0153] Uoc is the open circuit voltage of the solar cell, when the temperature is 25°C and the solar cell is placed in the AM1.5 spectrum condition with an irradiance of 100mW / cm 2 The terminal voltage when the solar cell is irradiated by a light source and is not connected to a load (i.e., open circuit);

[0154] Isc is the short-circuit current of the solar cell, which is the current when the temperature is 25°C and the solar cell is placed in the AM1.5 spectrum condition with an irradiance of 100mW / cm 2 The output current of the battery when it is short-circuited under the light source;

[0155] FF is the fill factor, which refers to the ratio of the maximum output power to the product of the open circuit voltage and the short circuit current. Solar cells with larger fill factor values ​​are better.

[0156] Yield rate, also known as "qualified rate", is one of the product quality indicators, which refers to the percentage of qualified products in all processed products.

[0157] As shown in Table 1, the effects of pre-printing optical hydrogen passivation and post-sintering electrical or optical hydrogen passivation employed in this application are significantly superior to those of optical hydrogen passivation performed after printing and sintering the cell, or prior to sintering. Adding a heat preservation step to the optical hydrogen passivation process can further enhance the hydrogen passivation effect.

[0158] The above description is only an illustration of some preferred embodiments of the present disclosure and the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the above-mentioned inventive concept. For example, the above-mentioned features are replaced with (but not limited to) technical features with similar functions disclosed in the embodiments of the present disclosure.

Claims

1. A method for hydrogen passivation of a solar cell, characterized in that: The method comprises at least two hydrogen passivations, at least one of which is before printing and at least one is after sintering; The hydrogen passivation before printing adopts light injection hydrogen passivation, and the light injection hydrogen passivation includes two steps of irradiation and heat preservation, wherein the temperature T2 of the heat preservation step is lower than the temperature T1 of the irradiation step; The hydrogen passivation after sintering is carried out by the same passivation method as that before printing; the hydrogen passivation after sintering is carried out by light injection hydrogen passivation, and the light injection hydrogen passivation after sintering includes two steps of irradiation and heat preservation, wherein the temperature T4 of the heat preservation step is lower than the temperature T3 of the irradiation step, and T3≤T1; or The hydrogen passivation after sintering and the hydrogen passivation before printing adopt different passivation methods; the hydrogen passivation after sintering adopts electric injection hydrogen passivation; The temperature difference between T1 and T2 is 300-600°C; and / or the temperature difference between T3 and T4 is 300-550°C; and / or the temperature difference between T1 and T3 is 0-50°C; The light injection hydrogen passivation before printing includes: irradiating and keeping warm the solar cell behind the back film, wherein the illumination intensity is 20 to 40 suns, the illumination temperature T1 is 500 to 700° C., and the illumination time is 5 to 20 seconds; and the keeping warm temperature T2 is 100 to 200° C., and the keeping warm time is 5 to 10 seconds; The post-sintering light-injected hydrogen passivation comprises: irradiating and heat-insulating the sintered solar cell, wherein the illumination intensity is 20 to 40 suns, the illumination temperature T3 is 500 to 650° C., and the illumination time is 5 to 10 s; and the heat-insulating temperature T4 is 100 to 200° C. and the heat-insulating time is 5 to 10 s; or The post-sintering electric injection hydrogen passivation includes: performing electric injection hydrogen passivation on the sintered solar cell, wherein the heating temperature of the electric injection hydrogen passivation is 100-250° C., the current intensity is 2-10 A, and the electric injection time is 400-2000 s.

2. A method for hydrogen passivation of a solar cell according to claim 1, characterized in that: The method comprises: Performing photo-injection hydrogen passivation on the solar cells behind the back film; Screen printing of solar cells passivated by photoinjection of hydrogen; Sintering the screen-printed solar cells; The sintered solar cell is subjected to electric injection hydrogen passivation or light injection hydrogen passivation.

3. Use of the solar cell hydrogen passivation method according to claim 1 or 2 in the preparation of solar cells.

4. The use according to claim 3, characterized in that Before the solar cell behind the back film is subjected to light injection hydrogen passivation, the process also includes: texturing, diffusion, etching, and back film.

5. A method for preparing a solar cell, characterized in that: The method includes the solar cell hydrogen passivation method according to claim 1 or 2.

6. A solar cell, characterized in that: The solar cell is prepared by the method for preparing the solar cell according to claim 5.

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