Solar cell preparation method and solar cell

Abstract

The invention discloses a solar cell preparation method and a solar cell, and belongs to the photovoltaic technical field, the method comprises the following steps: metallization treatment: carrying out metallization treatment on a semi-finished product sheet provided with an antireflection layer; ultraviolet light irradiation: ultraviolet light with a preset energy value is adopted to irradiate the surface of the metallized semi-finished product sheet, so that the antireflection layer releases free hydrogen elements, and the free hydrogen elements react with unsaturated groups in the antireflection layer to form first chemical bonds; the preset energy value of the ultraviolet light is 200mJ / cm < 2 >-30000mJ / cm < 2 > and comprises values at two ends, and the power of the ultraviolet light is 10Mw / cm < 2 >-8000Mw / cm < 2 > and comprises values at two ends; and obtaining the solar cell. The distribution of the hydrogen content in the antireflection layer can be adjusted, the utilization rate of effective hydrogen is improved, and then the hydrogen passivation level of the antireflection layer and the interface contact passivation level between adjacent film layers of the antireflection layer and the passivation layer are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, in particular to a solar cell preparation method and solar cell. BACKGROUND

[0002] At present, the main ways to improve the efficiency of photovoltaic solar cells are: (1) laser local doping, which accurately controls the doping concentration and area, reduces material defects, and improves cell performance through laser local doping technology; (2) light trapping structure, which reduces light reflection and absorption loss and further increases photoelectric conversion efficiency through the optimization of the layout of the back contact area and the front electrode; (3) passivation technology, which reduces surface recombination loss and improves cell efficiency by forming a passivation layer on the surface of the cell or by other methods. However, the above-mentioned efficiency improvement methods have many problems in process difficulty, which limits the efficiency improvement effect and makes it difficult to further improve the efficiency. SUMMARY

[0003] The purpose of the present application is to provide a solar cell preparation method and solar cell, thereby improving the efficiency of the solar cell.

[0004] To achieve the above-mentioned purpose, the present application provides a solar cell preparation method, comprising:

[0005] metallization treatment, the semi-finished product sheet provided with the anti-reflection layer is subjected to metallization treatment;

[0006] ultraviolet irradiation, the surface of the semi-finished product sheet after metallization treatment is irradiated with ultraviolet light having a preset energy value, so that the anti-reflection layer releases free hydrogen elements, and the free hydrogen elements react with unsaturated groups in the anti-reflection layer to form first chemical bonds; the preset energy value of the ultraviolet light is 200 mJ / cm 2 -30000 mJ / cm 2 , and includes both ends, the power of the ultraviolet light is 10 Mw / cm 2 -8000 Mw / cm 2 , and includes both ends;

[0007] obtaining the solar cell.

[0008] Optionally, the wavelength of the ultraviolet light is 10 nm-380 nm, and includes both ends;

[0009] The temperature of the ultraviolet light is 15℃-120℃, and includes both ends.

[0010] Optionally, the ultraviolet irradiation after the metallization treatment further comprises laser-assisted sintering, and the semi-finished product sheet after light injection is subjected to laser-assisted sintering.

[0011] Optionally, the metallization process comprises: printing slurry on the surface of the semi-finished wafer;

[0012] sintering the semi-finished wafer after printing at high temperature;

[0013] light injection on the semi-finished wafer after sintering.

[0014] Optionally, the surface of the semi-finished wafer after metallization is irradiated by the ultraviolet light with the preset energy value, the Si-H bond of the anti-reflection layer is opened to release the free hydrogen element, and the free hydrogen element reacts with the unsaturated group to form the first chemical bond.

[0015] Optionally, the surface of the semi-finished wafer after metallization is irradiated by the ultraviolet light with the preset energy value, the Si-H bond of the anti-reflection layer is opened to release the free hydrogen element, and the free hydrogen element reacts with the unsaturated group to form the first chemical bond.

[0016] Optionally, the chemical bond releasing the free hydrogen element is a second chemical bond, and the bond energy of the first chemical bond is greater than that of the second chemical bond.

[0017] To achieve the above-mentioned purpose, the application further provides a solar cell prepared by the above-mentioned solar cell preparation method, wherein the solar cell is provided with an anti-reflection layer, and the anti-reflection layer has a first chemical bond.

[0018] Optionally, the solar cell is provided with a passivation layer, and the anti-reflection layer is provided with a SiN layer close to the position of the passivation layer; the hydrogen element in the first chemical bond comes from the Si-H bond of the SiN layer. x x

[0019] Optionally, the solar cell comprises a substrate, and the passivation layer and the anti-reflection layer are arranged on the substrate; the anti-reflection layer is provided with a Si(ON) layer close to the position of the SiN layer; the Si(ON) layer is located on the side of the SiN layer away from the substrate; and the hydrogen element in the first chemical bond also comes from the Si-H bond and the Si-OH bond of the Si(ON) layer. x x x x x

[0020] Optionally, the anti-reflection layer further comprises a SiO2 layer located on the side away from the substrate.

[0021] ​​​​​​​Obviously, the solar cell preparation method provided in the application adopts the ultraviolet light with the energy value accurately measured to irradiate the cell piece after the metallization treatment, and the antireflection layer can release the free hydrogen element through the ultraviolet light with the specific energy value. Under the specific power of the ultraviolet light, the free hydrogen element reacts with the unsaturated group in the antireflection layer to generate a new chemical bond, i.e., the first chemical bond, so that the distribution of the hydrogen content in the antireflection layer can be adjusted through the reaction of the unsaturated group and the free hydrogen element, the utilization rate of the effective hydrogen is improved, and then the hydrogen passivation level of the antireflection layer and the interface contact passivation level between the adjacent film layers of the antireflection layer and the passivation layer are improved, and finally the efficiency of the solar cell is improved. It is worth noting that the free hydrogen element released by the antireflection layer is only part of the hydrogen element in the antireflection layer but not all, and part of the free hydrogen element may react with the unsaturated dangling bond of the passivation layer to generate a new chemical bond to improve the passivation level of the passivation layer. The free hydrogen element mainly comes from the chemical bond which is easy to release the free hydrogen element under the irradiation of the ultraviolet light with the specific energy value. If the energy value of the ultraviolet light is too large, excessive free hydrogen elements are released, the effect of the antireflection layer is reduced, and then the efficiency of the solar cell is reduced. If the energy value of the ultraviolet light is small, it is insufficient to release enough free hydrogen elements, or it is impossible to release the free hydrogen elements, and it is impossible to improve the hydrogen passivation level of the antireflection layer, and then it is impossible to improve the efficiency of the solar cell. If the power of the ultraviolet light is too high, the activity of the free hydrogen element is increased, which is not conducive to the formation of the first chemical bond between the unsaturated group and the free hydrogen element. If the power of the ultraviolet light is low, the activity of the free hydrogen element is low, and the formation of the first chemical bond is reduced. Therefore, the energy value and the power of the ultraviolet light pre-set by the ultraviolet light play a decisive role in improving the efficiency of the solar cell.

[0022] The application further provides a solar cell prepared by the solar cell preparation method provided in the application, and the efficiency of the solar cell can be higher than that of a solar cell prepared by a conventional efficiency improvement method. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of the provided drawings.

[0024] Figure 1 A flow chart of a solar cell preparation method provided in an embodiment of the application;

[0025] Figure 2 A position schematic diagram of each film layer in a cell piece provided in an embodiment of the application;

[0026] Figure 3 A flowchart of a conventional solar cell preparation method;

[0027] Figure 4 A flowchart of a solar cell preparation method provided by an embodiment of the present application;

[0028] Figure 5 A comparison chart of a solar cell provided by an embodiment of the present application and a solar cell without Raman spectrum under ultraviolet irradiation.

[0029] The reference signs are explained as follows:

[0030] 1-substrate; 2-emitter; 3-passivation layer; 4-first anti-reflection layer; 5-tunneling layer; 6-doped polysilicon layer; 7-second anti-reflection layer. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in a clear and complete manner with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0032] Reference is made to Figure 1 , Figure 1 A flowchart of a solar cell preparation method provided by an embodiment of the present application, which can include:

[0033] S101: metallization treatment, performing metallization treatment on a semi-finished piece provided with an anti-reflection layer.

[0034] It should be noted that the metallization treatment in the embodiment is a process of forming a metallized electrode, and the embodiment does not limit the specific manner of the metallization treatment, as long as the metallized electrode can be formed, for example, the metallization treatment in step S101 can include:

[0035] performing slurry printing on the surface of the semi-finished piece;

[0036] performing high-temperature sintering on the printed semi-finished piece;

[0037] performing photo injection on the sintered semi-finished piece.

[0038] Further, in order to improve the electrical performance of the solar cell, the semi-finished piece after metallization treatment and before ultraviolet irradiation can further include: laser-assisted sintering, performing laser-assisted sintering on the semi-finished piece after photo injection.

[0039] The embodiment is not limited to the specific type of the semi-finished sheet. For example, the semi-finished sheet can be a TOPCon (Tunnel Oxide Passivated Contact) semi-finished sheet, a BC (Back Contact) semi-finished sheet, or a PERC (Passivated Emitter and Rear Cell) semi-finished sheet.

[0040] It should be noted that, in addition to the anti-reflection layer, the cell in the embodiment is also provided with other film layers. The embodiment needs to be pre-coated before the cell is metallized to obtain a cell to be metallized. The type of the semi-finished sheet is different, and the corresponding coating method is different. Taking the TOPCon semi-finished sheet as an example, before step S101, the following steps can also be included:

[0041] The emitter, the passivation layer, and the first anti-reflection layer are sequentially arranged on the front surface of the substrate in a direction away from the substrate;

[0042] The tunnel layer, the doped polysilicon layer, and the second anti-reflection layer are sequentially arranged on the back surface of the substrate in a direction away from the substrate to obtain a semi-finished sheet; the anti-reflection layer includes the first anti-reflection layer and / or the second anti-reflection layer.

[0043] It should be noted that, since the front surface of the semi-finished sheet in the embodiment is provided with the first anti-reflection layer, and the back surface of the semi-finished sheet is provided with the second anti-reflection layer, the embodiment can irradiate the front surface of the semi-finished sheet in step S102, or irradiate the back surface of the semi-finished sheet, or irradiate both the front surface and the back surface of the semi-finished sheet. When the front surface of the semi-finished sheet is irradiated, the first anti-reflection layer releases free hydrogen elements; when the back surface of the semi-finished sheet is irradiated, the second anti-reflection layer releases free hydrogen elements.

[0044] Please refer to Figure 5, wherein ① is a characteristic peak of the second chemical bond (i.e. a chemical bond releasing free hydrogen elements), and ② is a characteristic peak of the first chemical bond. The intensity of the characteristic peak ① of the second chemical bond of the solar cell prepared by the method of irradiating ultraviolet light (referred to as an ultraviolet irradiation cell) is obviously lower than that of the solar cell not prepared by the method of irradiating ultraviolet light (referred to as a non-ultraviolet irradiation cell). The intensity of the characteristic peak ② of the first chemical bond of the ultraviolet irradiation cell is obviously higher than that of the non-ultraviolet irradiation cell. It can be seen that, by using the preparation method of the present application, under the irradiation of ultraviolet light with a preset specific energy value and power, the second chemical bond with a lower bond energy is first opened to release free hydrogen elements, and then the free hydrogen elements react with unsaturated groups to form the first chemical bond with a higher bond energy, i.e. the bond energy of the second chemical bond is low and easy to be opened to release free hydrogen elements; the free hydrogen elements react with unsaturated groups to form the first chemical bond with a high bond energy, and the first chemical bond is more stable.

[0045] The present embodiment does not limit the specific type of the substrate. For example, the substrate can be, but is not limited to, a silicon wafer substrate. The present embodiment does not limit the specific type of the substrate. For example, the substrate can be an N-type substrate or a P-type substrate. When the substrate is an N-type substrate, the emitter is a P-type emitter, and the doped polysilicon layer is an N-type doped polysilicon layer. When the substrate is a P-type substrate, the emitter is an N-type emitter, and the doped polysilicon layer is a P-type doped polysilicon layer.

[0046] The present embodiment does not limit the specific type of the passivation layer. For example, the passivation layer can be, but is not limited to, an Al2O3 layer. The present embodiment does not limit the specific type of the tunneling layer. For example, the tunneling layer can be, but is not limited to, a tunneling oxide layer.

[0047] The present embodiment does not limit the specific type of the first anti-reflective layer and the second anti-reflective layer. As long as the first anti-reflective layer and / or the second anti-reflective layer includes hydrogen elements, it is acceptable. Moreover, the types of the first anti-reflective layer and the second anti-reflective layer can be different or the same. For example, the first anti-reflective layer and the second anti-reflective layer can each include SiN x layers, Si(ON) x layers and SiO2 layers arranged in the direction away from the substrate.

[0048] The present embodiment sequentially arranges an emitter, a passivation layer and a first anti-reflective layer in the direction away from the substrate on the front side of the substrate. Specifically, the present embodiment includes:

[0049] forming the emitter by the part of the substrate close to the front side;

[0050] arranging the passivation layer on the surface of the emitter;

[0051] A first anti-reflection layer is arranged on the surface of the passivation layer.

[0052] The embodiment is not limited to a specific way of forming the emitter, and the specific way of forming the emitter can be determined according to the specific type of the emitter. For example, when the emitter is a P-type emitter, boron diffusion can be performed on the front surface of the substrate to form the emitter in a partial thickness of the substrate.

[0053] The embodiment is not limited to a specific way of arranging the passivation layer, as long as the passivation layer can be formed on the surface of the emitter.

[0054] The embodiment is not limited to a specific way of forming the first anti-reflection layer, as long as the first anti-reflection layer can be formed on the surface of the passivation layer.

[0055] Further, in order to improve the light trapping effect of the front surface of the substrate, the embodiment can further include texturing the front surface of the substrate before arranging the emitter on the front surface of the substrate.

[0056] The embodiment sequentially arranges, on the back surface of the substrate, a tunneling layer, a doped polysilicon layer, and a second anti-reflection layer in a direction away from the substrate, and specifically includes:

[0057] The tunneling layer is arranged on the back surface of the substrate.

[0058] The doped polysilicon layer is arranged on the surface of the tunneling layer.

[0059] The second anti-reflection layer is arranged on the surface of the doped polysilicon layer.

[0060] The embodiment is not limited to a specific way of arranging the tunneling layer, as long as the tunneling layer can be formed on the back surface of the substrate.

[0061] The embodiment is not limited to a specific way of arranging the doped polysilicon layer, and the specific way of arranging the doped polysilicon layer can be determined according to the specific type of the doped polysilicon layer. For example, when the doped polysilicon layer is an N-type doped polysilicon layer, an amorphous silicon layer can be formed on the surface of the tunneling layer, and phosphorus diffusion can be performed on the amorphous silicon layer to form the doped polysilicon layer.

[0062] The embodiment is not limited to a specific way of forming the second anti-reflection layer, as long as the second anti-reflection layer can be formed on the surface of the doped polysilicon layer. When the first anti-reflection layer and the second anti-reflection layer are of the same type, the first anti-reflection layer and the second anti-reflection layer can be formed in the same step.

[0063] It should be noted that, in the embodiment, after the boron diffusion on the front surface of the substrate, borosilicate glass is formed, which may be plated around the back surface of the substrate. Further, in order to remove the plated borosilicate glass, the embodiment can further include: polishing the back surface of the substrate by using an alkali solution, that is, alkali polishing.

[0064] It should be noted that, in the embodiment, after the phosphorus diffusion on the back surface of the substrate, phosphosilicate glass is formed, which may be plated around the front surface of the substrate. Further, in order to remove the plated phosphosilicate glass, the embodiment can further include: etching the front surface of the substrate after the phosphorus diffusion on the amorphous silicon layer.

[0065] The embodiment is not limited to the specific order of arranging the film layers on the front surface and the back surface of the substrate, as long as the film layers on the front surface and the back surface of the substrate can be formed, for example, can include:

[0066] Texturing is performed on the front surface of the substrate;

[0067] Boron diffusion is performed on the front surface of the substrate to form an emitter on part of the thickness of the substrate;

[0068] Polishing is performed on the back surface of the substrate by using an alkali solution;

[0069] A tunneling layer is formed on the back surface of the substrate by using an LPCVD method;

[0070] An amorphous silicon layer is formed on the surface of the tunneling layer, and phosphorus diffusion is performed on the amorphous silicon layer to form a doped polysilicon layer;

[0071] Etching is performed on the front surface of the substrate;

[0072] A passivation layer is formed on the surface of the emitter by using an ALD method;

[0073] A first anti-reflection layer is formed on the surface of the passivation layer, and a second anti-reflection layer is formed on the surface of the doped polysilicon layer.

[0074] S102: ultraviolet irradiation, using ultraviolet light with a preset energy value to irradiate the surface of the semi-finished product sheet after the metallization treatment, so that the anti-reflection layer releases free hydrogen elements, and the free hydrogen elements react with the unsaturated groups in the anti-reflection layer to form first chemical bonds; the preset energy value of the ultraviolet light is 200 mJ / cm 2 -30000 mJ / cm 2 , and includes both ends, the power of the ultraviolet light is 10 Mw / cm 2 -8000 Mw / cm 2 , and includes both ends; and a solar cell is obtained.

[0075] It should be noted that the anti-reflective layer before the ultraviolet light irradiation includes chemical bonds containing hydrogen elements (such as Si-H bonds, Si-OH bonds, etc.), and part of the chemical bonds containing hydrogen elements have defects. Under the irradiation of ultraviolet light with a specific energy value, the chemical bonds containing hydrogen elements with defects are easy to open and release hydrogen elements, and the chemical bonds containing hydrogen elements without defects are difficult to open. In this embodiment, the ultraviolet light with a specific energy value is irradiated, and the chemical bonds containing hydrogen elements with defects are more likely to release free hydrogen elements.

[0076] This embodiment does not limit the specific device for generating ultraviolet light with a preset energy value, and any ultraviolet light instrument can be used.

[0077] This embodiment does not limit the specific wavelength of the ultraviolet light, as long as it can release free hydrogen elements from the anti-reflective layer, and the free hydrogen elements react with the unsaturated groups in the anti-reflective layer to form the first chemical bonds. For example, the wavelength of the ultraviolet light can be 10 nm-380 nm, and the values at both ends are included.

[0078] It should be noted that in this embodiment, the energy value of the ultraviolet light can be adjusted by adjusting the irradiation time and the power of the ultraviolet light. This embodiment does not limit the specific value of the irradiation time, which is determined by the power of the ultraviolet light.

[0079] It should be noted that the temperature of the ultraviolet light in this embodiment also affects the process of releasing free hydrogen elements from the anti-reflective layer, and the free hydrogen elements reacting with the unsaturated groups in the anti-reflective layer to form the first chemical bonds. Preferably, the temperature of the ultraviolet light can be 15℃-120℃, and the values at both ends are included.

[0080] This embodiment does not limit the specific source of free hydrogen elements, which can be determined according to the specific type of the anti-reflective layer. For example, the anti-reflective layer can include SiN x layer, and the SiN x layer includes Si-H bonds;

[0081] Correspondingly, step S102 can include:

[0082] The surface of the semi-finished product after the metallization treatment is irradiated with ultraviolet light with a preset energy value, the Si-H bonds of the anti-reflective layer are opened to release free hydrogen elements, and the free hydrogen elements react with the unsaturated groups to form the first chemical bonds.

[0083] Further, in order to improve the anti-reflective effect, the anti-reflective layer in this embodiment can also include Si(ON) x layer, and the Si(ON) x layer includes Si-H bonds and Si-OH bonds;

[0084] Correspondingly, step S102 can also include:

[0085] The surface of the semi-finished wafer after the metallization treatment is irradiated with ultraviolet light having a preset energy value, the Si-OH bonds in the antireflection layer are opened to release free hydrogen elements, and the free hydrogen elements react with the unsaturated groups to form first chemical bonds.

[0086] It should be noted that under the irradiation of ultraviolet light, Si(ON) x layer will also release a small amount of hydrogen, most of which will overflow, and a small part will react with the unsaturated groups in the antireflection layer to form new chemical bonds, thereby improving the hydrogen passivation level of the antireflection layer and the interface contact passivation level between the antireflection layer and the adjacent film layer of the passivation layer, and ultimately improving the efficiency of the solar cell.

[0087] Further, in order to determine whether the efficiency of the solar cell reaches the expected performance index, the embodiment after ultraviolet irradiation can further include:

[0088] Efficiency testing of the semi-finished wafer after ultraviolet irradiation.

[0089] Further, the embodiment after efficiency testing of the semi-finished wafer after ultraviolet irradiation can further include: grading and packaging the semi-finished wafer according to the efficiency test results.

[0090] Based on the above embodiment, the application uses ultraviolet light with an accurately measured energy value to irradiate the wafer after the metallization treatment. The ultraviolet light with a specific energy value can make the antireflection layer release free hydrogen elements. Under the specific power of the ultraviolet light, the free hydrogen elements react with the unsaturated groups in the antireflection layer to form new chemical bonds, i.e. first chemical bonds, thereby adjusting the distribution of hydrogen content in the antireflection layer through the reaction of the unsaturated groups with the free hydrogen elements, improving the utilization rate of effective hydrogen, and further improving the hydrogen passivation level of the antireflection layer and the interface contact passivation level between the antireflection layer and the adjacent film layer of the passivation layer, and ultimately improving the efficiency of the solar cell. It should be noted that the free hydrogen elements released by the antireflection layer are only part of the hydrogen elements in the antireflection layer, not all, and some of the free hydrogen elements may react with the unsaturated dangling bonds of the passivation layer to form new chemical bonds to improve the passivation level of the passivation layer.

[0091] The solar cell prepared by the above-mentioned solar cell preparation method provided by the embodiment of the application can be provided with an antireflection layer having first chemical bonds.

[0092] It should be noted that the anti-reflective layer before ultraviolet light irradiation includes chemical bonds containing hydrogen elements (such as Si-H bonds, Si-OH bonds, etc.), and part of the chemical bonds containing hydrogen elements have defects. The first chemical bond in this embodiment is composed of hydrogen elements and unsaturated groups, and the hydrogen elements come from the above-mentioned defective chemical bonds containing hydrogen elements, which are released after being opened under ultraviolet light irradiation at a specific energy value. The anti-reflective layer in this embodiment includes not only the first chemical bond, but also the chemical bond containing hydrogen elements without defects, which is difficult to be opened under ultraviolet light irradiation, and therefore remains in the anti-reflective layer in the original chemical bond structure. The specific source of hydrogen elements in the first chemical bond is not limited in this embodiment and can be determined according to the specific type of the anti-reflective layer. For example, the solar cell is provided with a passivation layer, and the anti-reflective layer is provided with a SiN x layer near the position of the passivation layer; the hydrogen elements in the first chemical bond come from the Si-H bonds of the SiN x layer.

[0093] Further, in order to improve the anti-reflective effect, the solar cell in this embodiment includes a substrate, a passivation layer and an anti-reflective layer are arranged on the substrate, and a Si(ON) x layer is arranged near the position of the SiN x layer in the anti-reflective layer, the Si(ON) x layer is located on the side of the SiN x layer away from the substrate, and the hydrogen elements in the first chemical bond also come from the Si-H bonds and Si-OH bonds of the Si(ON) x layer. It should be noted that the Si(ON) x layer will also release a small amount of hydrogen under ultraviolet light irradiation, most of which will overflow, and a small part will react with the unsaturated groups in the anti-reflective layer to form the first chemical bond, thereby improving the hydrogen passivation level of the anti-reflective layer and the interface contact passivation level between the anti-reflective layer and the adjacent film layer of the passivation layer, and finally improving the efficiency of the solar cell.

[0094] Further, in order to improve the anti-reflective effect, the anti-reflective layer in this embodiment can also include a SiO2 layer, and the SiO2 layer is located on the side away from the substrate.

[0095] The specific refractive index of the anti-reflective layer is not limited in this embodiment and can be determined according to the actual situation. For example, the refractive index of the anti-reflective layer can be greater than 1.5. The specific thickness of the anti-reflective layer is not limited in this embodiment and can be determined according to the actual situation. For example, the thickness of the anti-reflective layer can be greater than 60 nm.

[0096] The specific type of the solar cell is not limited in this embodiment. For example, the cell piece can be a TOPCon cell, a BC cell or a PERC cell. For example, Figure 2As shown, when the solar cell is a TOPCon cell, the solar cell can include: a substrate 1; the front surface of the substrate 1 is sequentially provided with an emitter 2, a passivation layer 3 and a first anti-reflection layer 4 in the direction away from the substrate; the back surface of the substrate 1 is sequentially provided with a tunneling layer 5, a doped polysilicon layer 6 and a second anti-reflection layer 7 in the direction away from the substrate; the anti-reflection layer includes the first anti-reflection layer 4 and / or the second anti-reflection layer 7.

[0097] The embodiment does not limit the specific types of the above film layers, and reference can be made to the above embodiments of the solar cell preparation method, which will not be described here.

[0098] Based on the above embodiments, the solar cell is prepared by the above solar cell preparation method, and the efficiency can be higher than that of the solar cell prepared by the conventional efficiency improvement method.

[0099] The following will take the TOPCon cell as an example to illustrate the above solar cell preparation process, which is as follows:

[0100] 1. Preparation of the first semi-finished sheet before ultraviolet light irradiation:

[0101] The first semi-finished sheet is prepared through a normal process including: texturing, boron diffusion, alkali etching, LPCVD (low pressure chemical vapor deposition), phosphorus diffusion, front surface etching, ALD, front and back surface anti-reflection layer, metallization treatment (including: paste printing, high temperature sintering, light injection), laser-assisted sintering;

[0102] The film layer structure of the obtained first semi-finished sheet is as shown in Figure 2 : the front surface of the substrate 1 is sequentially provided with an emitter 2, a passivation layer 3 and a first anti-reflection layer 4 in the direction away from the substrate; the back surface of the substrate 1 is sequentially provided with a tunneling layer 5, a doped polysilicon layer 6 and a second anti-reflection layer 7 in the direction away from the substrate; the first anti-reflection layer 4 and the second anti-reflection layer 7 are of the same type;

[0103] The properties of the first anti-reflection layer 4 and the second anti-reflection layer 7 are as follows:

[0104] (1) The material includes SiN x , Si(ON) x and SiO2 layers sequentially arranged in the direction away from the passivation layer 3;

[0105] (2) The refractive index is greater than 1.5;

[0106] (3) The thickness is greater than 60 nm;

[0107] 2. Ultraviolet light irradiates the front surface and the back surface of the first semi-finished sheet to obtain a second semi-finished sheet or a third semi-finished sheet to improve the passivation level:

[0108] The parameters of the ultraviolet light are as follows:

[0109] (1) Power: 10 Mw / cm 2 -8000 Mw / cm 2 ; the irradiation time is determined by the power of the ultraviolet light, and by adjusting the irradiation time and the power of the ultraviolet light, the energy value of the ultraviolet light can be adjusted);

[0110] (2) Energy value (E): 200 mJ / cm 2 -30000 mJ / cm 2 ;

[0111] (3) Temperature (ultraviolet light irradiation temperature): 15℃-120℃;

[0112] (4) Wavelength: 10nm-380nm;

[0113] The structure of the second semi-finished sheet or the third semi-finished sheet prepared after ultraviolet light irradiation has no change compared with the structure of the first semi-finished sheet before irradiation, only the internal structure of the first anti-reflective layer 4 and the second anti-reflective layer 7 has changed, the defective chemical bonds (including the defective Si-H bonds in the SiN x layer, the defective Si-H bonds and Si-OH bonds in the Si(ON) x layer) in the first anti-reflective layer 4 and the second anti-reflective layer 7 are opened, and the passivation level of the first anti-reflective layer 4 and the second anti-reflective layer 7 is increased, which is mainly due to the increase of the utilization rate of effective hydrogen in the first anti-reflective layer 4 and the second anti-reflective layer 7.

[0114] Change to the current battery preparation process: the process before metallization treatment (including paste printing, high-temperature sintering, light injection, laser-assisted sintering) remains unchanged, and other processes are changed as shown in Figure 3 and Figure 4 , in this embodiment, the ultraviolet light irradiation is performed after laser-assisted sintering.

[0115] The first semi-finished sheet prepared by one group of steps 1 is used in the comparison group; the first semi-finished sheet prepared by two groups of steps 2 is used in the experimental group; the I (current)-V (voltage) test is performed on the three groups of first semi-finished sheets without ultraviolet light irradiation, and the initial conversion efficiency (Eta) of the three groups of first semi-finished sheets is obtained; then the first semi-finished sheet of the experimental group is irradiated by the ultraviolet light instrument, wherein the maximum power of the ultraviolet light instrument is set to 20%, the irradiation time is set to 20s, and the difference in the energy value of the ultraviolet light of the two experimental groups is caused by the error of the ultraviolet light instrument during adjustment; the I-V test is performed on the second semi-finished sheet and the third semi-finished sheet obtained after irradiation of the experimental group, and the Eta of the second semi-finished sheet and the third semi-finished sheet of the experimental group after ultraviolet light irradiation is obtained, and all the efficiency test results are shown in Table 1 as follows:

[0116] Table 1 Efficiency test results

[0117]

[0118] According to the efficiency test results, it is found that the efficiency of the second and third semi-finished sheets irradiated by ultraviolet light is obviously improved compared with the first semi-finished sheet without ultraviolet irradiation.

[0119] 3. According to the efficiency test results, the second semi-finished sheet is packaged in different grades.

[0120] Among them, the conversion efficiency (Eta) and I-V test, the equipment is a solar simulator, IV tester and four-wire method probe. Test method: A. Place the battery in the center of the simulator, and shield the edge of 5mm to avoid edge light leakage; B. Apply a scanning voltage from -0.5V to Voc+0.5V, with a step of 10mV, and record the IV curve; C. Extract Voc (voltage when current=0), Isc (current when voltage=0) from the curve; D. Calculate the maximum power point (Pmax=Vmpp×Impp), fill factor FF=Pmax / (Voc×Isc); E. Efficiency Eta=(Pmax / incident light power)×100% (incident light power is calibrated by standard cell).

[0121] The principles and implementation manners of the present application are described by applying specific examples in the present text, and there is a progressive relationship between each embodiment, and each embodiment mainly explains the difference from other embodiments, and the same and similar parts between each embodiment can be referred to each other. The above embodiment description is only used to help understand the method and its core idea of the present application. For ordinary skilled in the art, some improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

[0122] It should also be noted that in the present specification, relationship terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement "including a…" does not exclude the presence of another identical element in the process, method, article or equipment including the element.

Claims

1. A method for producing a solar cell, characterized by, The method comprises: a metallization process, in which a semi-finished sheet provided with an anti-reflective layer is subjected to the metallization process; ultraviolet light irradiation, irradiating the surface of the semi-finished sheet after the metallization treatment with ultraviolet light having a preset energy value, so that the antireflection layer releases free hydrogen elements, and the free hydrogen elements react with the unsaturated groups in the antireflection layer to form first chemical bonds; the preset energy value of the ultraviolet light is 200 mJ / cm 2 -30000 mJ / cm 2 , and including both ends, the power of the ultraviolet light is 10 Mw / cm 2 -8000 Mw / cm 2 , and including both ends. obtaining the solar cell.

2. The solar cell manufacturing method according to claim 1, wherein The wavelength of the ultraviolet light is 10-380 nm, and the values at both ends are included. The temperature of the ultraviolet light is 15-120℃, and the values at both ends are included.

3. The method of claim 1, wherein the method further comprises: The metallization process is followed by laser-assisted sintering before the ultraviolet light irradiation, in which the semi-finished sheet after light injection is subjected to laser-assisted sintering.

4. The solar cell manufacturing method according to claim 1, wherein The metallization process includes slurry printing on the surface of the semi-finished sheet. The semi-finished sheet after printing is subjected to high-temperature sintering. The semi-finished sheet after sintering is subjected to light injection.

5. The solar cell preparation method according to any one of claims 1-4, characterized in that: The surface of the semi-finished sheet after metallization is irradiated with the ultraviolet light having the preset energy value to open the Si-H bond of the anti-reflective layer, so as to release the free hydrogen element, and the free hydrogen element reacts with the unsaturated group to form the first chemical bond.

6. The solar cell preparation method according to claim 5, characterized in that: The surface of the semi-finished sheet after metallization is irradiated with the ultraviolet light having the preset energy value to open the Si-OH bond in the anti-reflective layer, so as to release the free hydrogen element, and the free hydrogen element reacts with the unsaturated group to form the first chemical bond.

7. The method of claim 1, wherein the method further comprises: The chemical bond releasing the free hydrogen element is a second chemical bond, and the bond energy of the first chemical bond is greater than that of the second chemical bond.

8. A solar cell produced by the method according to any one of claims 1 to 7, characterized by The solar cell is provided with an anti-reflective layer, and the anti-reflective layer has a first chemical bond.

9. The solar cell of claim 8, wherein, The solar cell is provided with a passivation layer, and the antireflection layer is provided with SiN near the passivation layer. x Layer; the hydrogen element in the first chemical bond comes from the SiN x Si-H bonds in the layer.

10. The solar cell of claim 9, wherein, The solar cell comprises a substrate, the substrate is provided with the passivation layer and the anti-reflection layer, the Si(ON) x layer is arranged in the anti-reflection layer close to the SiN x layer, the Si(ON) x layer is located on the side of the SiN x layer away from the substrate, the hydrogen element in the first chemical bond also comes from the Si-H bond and the Si-OH bond of the Si(ON) x layer.

11. The solar cell according to claim 8 or 9, characterized in that, The anti-reflective layer further comprises a SiO2 layer located away from the substrate.

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