Solar cell and preparation method thereof, laminated cell and photovoltaic module

Abstract

The invention relates to a solar cell and a preparation method thereof, a laminated cell and a photovoltaic module. The preparation method of the solar cell comprises the following steps: providing a substrate; forming an initial diffusion layer and a first glass layer which are laminated on the first surface, and forming an initial tunneling layer, an initial doped conductive layer and a second glass layer which are laminated on the second surface; the first glass layer is located at one side of the initial diffusion layer away from the substrate, and the second glass layer is located at one side of the initial doped conductive layer away from the initial tunneling layer; removing the part of the first glass layer in the second area and the part of the second glass layer in the fourth area by adopting a chain photoetching process; removing the part of the initial diffusion layer in the second region and the parts of the initial tunneling layer and the initial doped conductive layer in the fourth region; and removing the part of the first glass layer in the first area and the part of the second glass layer in the third area. Because the first glass layer and the second glass layer are patterned by adopting the photoetching method, the thermal damage phenomenon of the battery can be effectively improved.

Description

TECHNICAL FIELD

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

[0002] Topcon (Tunnel Oxide Passivated Contact) cells are a kind of tunnel oxide passivated contact solar cells with silicon as a substrate. Since the tunnel oxide with excellent charge transport characteristics is used as the charge transport layer on the back of the cell, and a doped polysilicon layer is deposited to form a back passivation contact structure, surface recombination and metal contact recombination can be effectively reduced, and the open voltage and energy conversion efficiency can be improved.

[0003] However, the manufacturing process of the related Topcon cell is relatively complex, and a high temperature is generated in the process, which leads to heat loss and affects the conversion efficiency of the cell. SUMMARY

[0004] Therefore, it is necessary to provide a solar cell, a preparation method thereof, a stacked cell and a photovoltaic module to solve the problems of complex manufacturing process and heat loss of the Topcon cell.

[0005] A preparation method of a solar cell comprises the following steps:

[0006] providing a substrate; the substrate has a first surface and a second surface arranged opposite along the thickness direction of the substrate, the first surface has a first region and a second region, and the second surface has a third region and a fourth region;

[0007] forming an initial diffusion layer and a first glass layer in a stack on the first surface, and forming an initial tunnel layer, an initial doped conductive layer and a second glass layer in a stack on the second surface; the first glass layer is located on the side of the initial diffusion layer away from the substrate, and the second glass layer is located on the side of the initial doped conductive layer away from the initial tunnel layer;

[0008] removing the part of the first glass layer located in the second region and the part of the second glass layer located in the fourth region by using a chain photolithography process;

[0009] removing the part of the initial diffusion layer located in the second region, and the part of the initial tunnel layer and the initial doped conductive layer located in the fourth region, to form a diffusion layer, a tunnel layer and a doped conductive layer;

[0010] removing the part of the first glass layer located in the first region and the part of the second glass layer located in the third region.

[0011] In one of the embodiments, the step of removing the part of the initial diffusion layer located in the second region and the part of the initial tunneling layer and the initial doped conductive layer located in the fourth region to form a diffusion layer, a tunneling layer and a doped conductive layer comprises:

[0012] The part of the initial diffusion layer located in the second region and the part of the initial tunneling layer and the initial doped conductive layer located in the fourth region are removed by using an alkaline texturing solution to form a textured structure in the second region and the fourth region.

[0013] In one of the embodiments, the alkaline texturing solution is a NaOH solution, and the concentration of the alkaline texturing solution is 0.5%-5%.

[0014] In one of the embodiments, the step of removing the part of the first glass layer located in the first region and the part of the second glass layer located in the third region comprises:

[0015] The part of the first glass layer located in the first region and the part of the second glass layer located in the third region are removed by using an acidic solution.

[0016] In one of the embodiments, the acidic solution is an HF solution, and the concentration of the acidic solution is 10%-70%.

[0017] In one of the embodiments, the step of removing the part of the first glass layer located in the second region and the part of the second glass layer located in the fourth region by using a chain photolithography process comprises:

[0018] A first mask is formed on the first glass layer, and a second mask is formed on the second glass layer; the first mask is coincident with the first region in the orthographic projection of the substrate, and the second mask is coincident with the third region in the orthographic projection of the substrate.

[0019] The part of the first glass layer located in the second region and the part of the second glass layer located in the fourth region are removed to expose the part of the initial diffusion layer located in the second region and the part of the initial doped conductive layer located in the fourth region.

[0020] In one of the embodiments, the step of removing the part of the first glass layer located in the second region and the part of the second glass layer located in the fourth region to expose the part of the initial diffusion layer located in the second region and the part of the initial doped conductive layer located in the fourth region comprises:

[0021] A portion of the first glass layer located in the second region and a portion of the second glass layer located in the fourth region are removed by using an acid solution to expose a portion of the initial diffusion layer located in the second region and a portion of the initial doped conductive layer located in the fourth region.

[0022] In one embodiment, the acid solution is an HF solution, and the concentration of the acid solution is 10%-70%.

[0023] In one embodiment, the step of forming a first mask on the first glass layer includes:

[0024] coating photoresist on the first glass layer;

[0025] placing a first mask on the first glass layer coated with the photoresist, the first mask having a first hollow portion, the first hollow portion being arranged in correspondence with the first region;

[0026] irradiating the photoresist to denature a portion of the photoresist located in the first region to form the first mask;

[0027] removing the first mask;

[0028] removing a portion of the photoresist located in the second region.

[0029] In one embodiment, the step of forming a second mask on the second glass layer includes:

[0030] coating photoresist on the second glass layer;

[0031] placing a second mask on the second glass layer coated with the photoresist, the second mask having a second hollow portion, the second hollow portion being arranged in correspondence with the third region;

[0032] irradiating the photoresist to denature a portion of the photoresist located in the third region to form the second mask;

[0033] removing the second mask;

[0034] removing a portion of the photoresist located in the fourth region.

[0035] In one embodiment, the step of forming a first mask on the first glass layer includes:

[0036] The initial diffusion layer, the first glass layer, the around-plating doped conductive layer and the around-plating glass layer are formed on the first surface in sequence, and the initial tunneling layer, the initial doped conductive layer and the second glass layer are formed on the second surface in sequence.

[0037] The around-plating doped conductive layer and the around-plating glass layer are removed by using an alkaline solution.

[0038] A solar cell is prepared by using the preparation method of the solar cell.

[0039] A laminated cell includes a top cell and a bottom cell, and the bottom cell is the solar cell.

[0040] A photovoltaic module includes the solar cell or the laminated cell.

[0041] The preparation method of the solar cell can effectively improve the heat damage phenomenon of the cell and effectively improve the conversion efficiency of the cell by using the photolithography method to perform the patterning treatment on the first glass layer and the second glass layer, compared with the laser patterning treatment. Moreover, the process flow is simplified and the cell preparation cost is reduced by simultaneously performing the patterning treatment on the first glass layer and the second glass layer. In addition, the light parasitic absorption is reduced and the conversion efficiency of the cell is further improved by removing part of the doped conductive layer and the tunneling layer. BRIEF DESCRIPTION OF DRAWINGS

[0042] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The embodiments of the application illustrated in the drawings, and their description, are not meant to limit the application to a single preferred embodiment.

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0044] Figure 1 It is a flowchart of the preparation method of the solar cell of an embodiment of the present application.

[0045] Figure 2 It is a schematic diagram of step S110 of the preparation method of the solar cell of an embodiment of the present application.

[0046] Figure 3 It is a schematic diagram of step S121 of the preparation method of the solar cell of an embodiment of the present application.

[0047] Figure 4A schematic diagram of step S122 of the method for manufacturing the solar cell according to an embodiment of the present application.

[0048] Figure 5 A schematic diagram of step S123 of the method for manufacturing the solar cell according to an embodiment of the present application.

[0049] Figure 6 A schematic diagram of step S124 of the method for manufacturing the solar cell according to an embodiment of the present application.

[0050] Figure 7 A schematic diagram of step S125 of the method for manufacturing the solar cell according to an embodiment of the present application.

[0051] Figure 8 A schematic diagram of step S126 of the method for manufacturing the solar cell according to an embodiment of the present application.

[0052] Figure 9 A schematic diagram of step S127 of the method for manufacturing the solar cell according to an embodiment of the present application.

[0053] Figure 10 A schematic diagram of step S131 of the method for manufacturing the solar cell according to an embodiment of the present application.

[0054] Figure 11 A schematic diagram of step S132 of the method for manufacturing the solar cell according to an embodiment of the present application.

[0055] Figure 12 A schematic diagram of step S140 of the method for manufacturing the solar cell according to an embodiment of the present application.

[0056] Figure 13 A schematic diagram of step S150 of the method for manufacturing the solar cell according to an embodiment of the present application.

[0057] BRIEF DESCRIPTION OF DRAWINGS

[0058] 11, substrate; 11a, first surface; 11b, second surface; 12, initial diffusion layer; 121, diffusion layer; 13, first glass layer; 14, initial tunneling layer; 141, tunneling layer; 15, initial silicon layer; 152, initial doped conductive layer; 1521, doped conductive layer; 154, around-plating doped conductive layer; 16, second glass layer; 17, around-plating glass layer; 20, first mask; 30, second mask. DETAILED DESCRIPTION

[0059] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of different ways beyond the specific embodiments described herein and by one of ordinary skill in the art without departing from the spirit and scope of the present application, and it is therefore intended that all such variations be considered as falling within the scope of the present application. It should be understood that the descriptions of the present application are merely intended to help understand the principles of the present application, and should not be used to restrict the scope of the present application.

[0060] In the description of the present application, it should be understood that, if these terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only intended to facilitate the description of the present application and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0061] In addition, if these terms "first", "second" appear, these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, if the term "a plurality of" appears, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified and limited.

[0062] In the present application, unless otherwise explicitly specified and limited, if the terms "mounting", "connecting", "connecting", "fixing" and the like appear, these terms should be interpreted broadly. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0063] In the present application, unless specifically defined and limited otherwise, if there is a description of a first feature "on" or "under" a second feature, etc., it can mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "over", "above" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only means that the first feature is horizontally higher than the second feature. The first feature "under", "below" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only means that the first feature is horizontally lower than the second feature.

[0064] It should be noted that if an element is referred to as being "fixed to" or "set to" another element, it can be directly on the other element or there can be an intermediate element. If an element is considered to be "connected" to another element, it can be directly connected to the other element or there can be an intermediate element. If present, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in the present application are for illustrative purposes only and do not represent the only implementation.

[0065] Referring to Figure 1 Embodiments of the present application provide a preparation method of a solar cell, for the preparation of a solar cell, specifically a Topcon (Tunnel Oxide Passivated Contact) cell. It can be understood that the preparation method of the solar cell can also be used for the preparation of other types of solar cells, which are not specifically limited here.

[0066] As described in the background, in the process of Topcon cell, laser is usually used for patterning the cell, but the high temperature generated by laser operation will cause irreversible thermal damage to the cell, thereby affecting the passivation effect and reducing the photoelectric conversion efficiency of the cell. Moreover, the required time of laser operation is relatively long, thereby affecting the production efficiency of the cell and causing a bottleneck in production capacity.

[0067] Based on the above technical problems, as Figure 1 The present application provides a preparation method of a solar cell, comprising the following steps:

[0068] Step S110: providing a substrate; the substrate has a first surface and a second surface oppositely arranged along the thickness direction of itself, the first surface has a first region and a second region, and the second surface has a third region and a fourth region.

[0069] In combination with Figure 2As shown, the substrate 11 can be an N-type semiconductor substrate or a P-type semiconductor substrate. Specifically, the N-type semiconductor substrate is doped with an N-type doping element, which can be at least one of a group V element such as a phosphorus (P) element, a bismuth (Bi) element, an antimony (Sb) element, or an arsenic (As) element. The P-type semiconductor substrate is doped with a P-type element, which can be at least one of a group III element such as a boron (B) element, an aluminum (Al) element, a gallium (Ga) element, or an indium (In) element.

[0070] The substrate 11 has a rectangular flat plate structure, and has a first surface 11a and a second surface 11b arranged opposite and horizontally along the thickness direction of the substrate 11. The first surface 11a is a surface of the substrate 11 facing the light-receiving side of the solar cell, and the second surface 11b is a surface of the substrate 11 facing the back light side of the solar cell.

[0071] Further, the first surface 11a has a first region and a second region. The first region is a region provided with an electrode, and the second region is a region of the first surface 11a other than the first region. The shapes and sizes of the first region and the second region can be set as needed. The second surface 11b has a third region and a fourth region. The third region is a region provided with an electrode, and the fourth region is a region of the second surface 11b other than the third region. The shapes and sizes of the third region and the fourth region can be set as needed. It can be understood that the positions of the first region and the third region, and the positions of the second region and the fourth region can completely correspond in the thickness direction of the substrate 11, or can be misaligned, which is not limited herein.

[0072] In some embodiments, the step S110 can specifically include the following steps: providing an N-type silicon wafer, first removing oil stains on the surface of the silicon wafer by pre-cleaning, then removing a mechanical damage layer generated in the cutting process of the silicon wafer by using an alkali solution and performing texturing treatment, so as to form a rough and uneven textured structure on the surface of the silicon wafer as a substrate.

[0073] The textured structure is not only conducive to increasing the light-receiving area, but also conducive to reducing the reflection of sunlight on the surface of the solar cell, thereby improving the absorption rate of sunlight on the surface of the solar cell, and ultimately improving the photoelectric conversion efficiency of the solar cell.

[0074] After the step S110, the method further includes a step S120 of forming a laminated initial diffusion layer and a first glass layer on the first surface, and forming a laminated initial tunneling layer, an initial doped conductive layer, and a second glass layer on the second surface. The first glass layer is located on the side of the initial diffusion layer away from the substrate, and the second glass layer is located on the side of the initial doped conductive layer away from the initial tunneling layer.

[0075] In some embodiments, the step S120 specifically includes the following steps:

[0076] Step S121: forming an initial diffusion layer and a first glass layer on the first surface and the second surface of the substrate respectively; the first glass layer is located on the side of the initial diffusion layer away from the substrate.

[0077] Please refer to Figure 1 , Figure 2 and Figure 3 , in some embodiments, the first surface 11a and the second surface 11b of the substrate 11 are subjected to boron diffusion treatment, the substrate 11 is placed in a diffusion furnace, and the boron source (such as boron tribromide (BBr3) or boron trichloride (BCl3)) is evaporated or sublimated by heating. The boron atoms generated by the diffusion source are heated to a certain temperature and diffuse into the substrate 11 to form an initial diffusion layer 12 on the first surface 11a and the second surface 11b of the substrate 11, respectively. At the same time, the boron atoms and the silicon atoms on the surface of the substrate 11 react to form boron-silicon compounds, which melt at high temperatures to form a first glass layer 13 on the side surface of the initial diffusion layer 12 away from the substrate 11.

[0078] In the above boron diffusion process, the heating temperature is 800-1200°C, the diffusion time is 2-5h, and the thickness of the first glass layer 13 formed is 100-200nm. It can be understood that the boron diffusion process is not limited to this manner and process parameters, and can be set as needed to meet different requirements.

[0079] Step S122: removing the first glass layer on the side of the second surface of the substrate.

[0080] Please refer to Figure 4 , in some embodiments, the first glass layer 13 on the side of the second surface 11b of the substrate 11 is removed by cleaning with an acidic solution to expose the initial diffusion layer 12. The acidic solution can be a hydrofluoric acid (HF) solution, and the concentration of the HF solution is 10%-70%. The reaction time can be 60s.

[0081] It can be understood that the manner and process parameters for removing the first glass layer 13 are not limited to this, and can be set as needed to meet different requirements.

[0082] Step S123: removing the initial diffusion layer on the second surface of the substrate.

[0083] Please refer to Figure 5 , in some embodiments, the initial diffusion layer 12 on the second surface 11b of the substrate 11 is removed by using an alkaline solution to expose the second surface 11b of the substrate 11. The alkaline solution can be a potassium hydroxide (KOH) solution, and the concentration of the KOH solution is 0.5%-5%. The polishing temperature is 60-80°C, and the reaction time is 100-900s.

[0084] It can be understood that the way and process parameters for removing the initial diffusion layer 12 are not limited to this, and can be set as needed to meet different requirements.

[0085] In combination with Figure 6 As shown in step S124, an initial tunneling layer is formed on the second surface of the substrate.

[0086] In some embodiments, the substrate 11 is placed in a deposition furnace, and then at least one of silicon oxide, titanium oxide, silicon nitride, aluminum oxide, and hafnium oxide material is deposited on the second surface 11b of the substrate 11 to form an initial tunneling layer 14 for reducing the surface recombination rate. The heating temperature of the deposition furnace is 400-1000°C, and the thickness of the initial tunneling layer 14 is 1-10 nm.

[0087] It can be understood that the way and process parameters for forming the initial tunneling layer 14 are not limited to this, and can be set as needed to meet different requirements.

[0088] Step S125: Forming an initial silicon layer on the first surface side and the second surface side of the substrate.

[0089] In combination with Figure 7 In some embodiments, the substrate 11 is placed in a deposition furnace, and then at least one of amorphous silicon or microcrystalline silicon is deposited on the initial tunneling layer 14 of the substrate 11 and the first glass layer 13 of the substrate 11 to form an initial silicon layer 15, which provides a basis for the subsequent phosphorus diffusion process and forms a good field effect passivation and contact.

[0090] The heating temperature of the deposition furnace is 400-1000°C, and the thickness of the initial silicon layer 15 is 50-400 nm. It can be understood that the way of forming the initial silicon layer 15 is not limited to this, and can be set as needed to meet different requirements.

[0091] Step S126: Doping treatment is performed on the initial silicon layer on the second surface side of the substrate to form an initial doped conductive layer and a phosphorus silicon glass layer.

[0092] In combination with Figure 8 As shown in some embodiments, the substrate 11 is placed in a diffusion furnace, and the phosphorus source (such as POC l3 ) reacts with the surface of the initial silicon layer 15 to form phosphorus atoms and diffuse into the initial silicon layer 15 on the second surface 11b side of the substrate 11. The high temperature during the diffusion process can convert amorphous silicon into polycrystalline silicon, thereby converting the initial silicon layer 15 into an initial doped conductive layer 152. At the same time, the phosphorus atoms chemically react with the silicon atoms on the surface of the substrate 11 to form phosphorus silicon compounds, which melt at high temperatures to form a second glass layer 16 on the surface of the initial doped conductive layer 152 away from the substrate 11.

[0093] The diffusion furnace has a temperature of 700-1000℃, a diffusion time of 1h-3h, and the second glass layer 16 has a thickness of 20nm-100nm. It should be understood that the doping method and process parameters are not limited to the above, and can be set according to different requirements.

[0094] Further, the initial doping conductive layer 152 and the second glass layer 16 are formed on the side of the second surface 11b of the substrate 11, and the spin-on doping conductive layer 154 and the spin-on glass layer 17 are formed on the side of the first surface 11a of the substrate 11 and stacked on the first glass layer 13.

[0095] Therefore, the step S120 further includes a step S127 of removing the spin-on doping conductive layer and the spin-on glass layer on the side of the first surface of the substrate.

[0096] Please refer to Figure 9 In some embodiments, the spin-on glass layer 17 on the side of the first surface 11a is first etched by using an alkaline solution to expose the spin-on doping conductive layer 154 below, and then the silicon surface is etched to remove the spin-on doping conductive layer 154.

[0097] The alkaline solution is a sodium hydroxide (NaOH) solution, the concentration of the NaOH solution is 0.5%-5%, the reaction temperature is 60℃-80℃, and the reaction time is 100s-1000s. It should be understood that the method of removing the spin-on doping conductive layer 154 and the spin-on glass layer 17 is not limited to the above, and can be set according to different requirements.

[0098] Thus, after the above step S120, the first surface 11a of the substrate 11 forms the initial diffusion layer 12 and the first glass layer 13 stacked thereon, and the second surface 11b of the substrate 11 forms the initial tunneling layer 14, the initial doping conductive layer 152 and the second glass layer 16 stacked thereon.

[0099] As shown in Figure 1 After the step S120, the step S130 of removing the part of the first glass layer in the second region and the part of the second glass layer in the fourth region by using a chain photolithography process is further included.

[0100] In some embodiments, the step S130 specifically includes the following steps:

[0101] The step S131 of forming a first mask on the first glass layer and a second mask on the second glass layer is included, the first mask is coincided with the first region in the orthographic projection of the substrate, and the second mask is coincided with the third region in the orthographic projection of the substrate.

[0102] Please refer to Figure 10As shown, the first mask 20 has the same shape as the first region, so as to cover the part of the first glass layer 13 located in the first region and expose the part of the first glass layer 13 located in the second region, and further protect the part of the first glass layer 13 located in the first region and expose the part of the first glass layer 13 located in the second region in the subsequent process. The second mask 30 has the same shape as the third region, so as to cover the part of the second glass layer 16 located in the third region and expose the part of the second glass layer 16 located in the fourth region, and further protect the part of the second glass layer 16 located in the third region and expose the part of the second glass layer 16 located in the fourth region in the subsequent process.

[0103] In some embodiments, the step of forming the first mask on the first glass layer in step S131 comprises:

[0104] S1310: applying photoresist on the first glass layer.

[0105] Specifically, the photoresist covers the entire surface of the first glass layer 13 away from the substrate 11. Photoresist, also known as photoresist, refers to a kind of etching resistant film material whose solubility changes through the irradiation or radiation of ultraviolet light, electron beam, ion beam, X-ray, etc.

[0106] S1311: placing a first mask plate on the first glass layer coated with photoresist, the first mask plate having a first hollow part, the first hollow part being arranged corresponding to the first region.

[0107] Specifically, the first mask plate has a flat plate structure, the first hollow part of the first mask plate penetrates the upper and lower surfaces of the first mask plate along the thickness direction of the first mask plate, the shape of the first hollow part is the same as that of the first region, and the edges of the orthographic projection of the first hollow part on the substrate 11 coincide with the edges of the first region. Therefore, the first mask plate covers the part of the photoresist located in the second region, and the part of the photoresist located in the first region is exposed.

[0108] S1312: irradiating the photoresist to denature the part of the photoresist located in the first region to form the first mask.

[0109] Specifically, ultraviolet light, electron beam, ion beam, X-ray, etc. can be used to irradiate the photoresist. Since the part of the photoresist corresponding to the first hollow part (i.e. located in the first region) is exposed, it is denatured and solidified to form the first mask 20, and the orthographic projection of the first mask 20 on the substrate 11 coincides with the first region. The part of the photoresist covered by the first mask plate (i.e. located in the second region) has not been irradiated and remains in the initial state.

[0110] S1313: removing the first mask plate.

[0111] Specifically, the first mask is removed from the first glass layer 13.

[0112] S1314: removing the part of the photoresist located in the second region.

[0113] Specifically, since the part of the photoresist covered by the first mask (i.e. the part located in the second region) is not denatured and solidified, it can be removed by cleaning, so that only the first mask 20 covering the first glass layer 13 located in the first region remains.

[0114] In some embodiments, the step of forming a second mask on the second glass layer in step S131 includes:

[0115] S1315: applying photoresist on the second glass layer.

[0116] Specifically, the photoresist covers the entire surface of the second glass layer 16 away from the substrate 11.

[0117] S1316: placing a second mask on the second glass layer coated with photoresist, the second mask having a second hollow part arranged corresponding to the third region.

[0118] Specifically, the second mask is in a flat plate structure, the second hollow part of the second mask penetrates the upper and lower surfaces of the second mask along the thickness direction of the second mask, the shape of the second hollow part is the same as that of the third region, and the edges of the orthographic projection of the second mask on the substrate 11 coincide with the edges of the third region. Therefore, the second mask covers the part of the photoresist located in the fourth region, and the part of the photoresist located in the third region is exposed.

[0119] S1317: irradiating the photoresist to make the part of the photoresist located in the third region denatured to form a second mask.

[0120] Specifically, the photoresist can be irradiated by ultraviolet light, electron beam, ion beam, X-ray, etc. Since the part of the photoresist corresponding to the second hollow part (i.e. the part located in the third region) is exposed, it is denatured and solidified under irradiation to form a second mask 30, and the orthographic projection of the second mask 30 on the substrate 11 coincides with the third region. The part of the photoresist covered by the second mask (i.e. the part located in the fourth region) does not receive irradiation and remains in the initial state.

[0121] S1318: removing the second mask.

[0122] Specifically, the first mask is removed from the first glass layer 13.

[0123] S1319: removing the part of the photoresist located in the fourth region.

[0124] Specifically, the portion of the photoresist covered by the second mask (i.e. the portion located in the fourth region) is not denatured and solidified, and thus can be removed by cleaning, so that only the second mask 30 covering the second glass layer 16 located in the third region remains.

[0125] After step S131, step S132 is further included: using an acidic solution to remove the portion of the first glass layer located in the second region and the portion of the second glass layer located in the fourth region, so as to expose the portion of the initial diffusion layer located in the second region and the portion of the initial doped conductive layer located in the fourth region.

[0126] Please refer to Figure 11 Specifically, since the portion of the first glass layer 13 located in the first region is covered and protected by the first mask 20, and the portion of the second glass layer 16 located in the third region is covered and protected by the second mask 30, the portion of the first glass layer 13 located in the second region and the portion of the second glass layer 16 located in the fourth region can be accurately removed by using the acidic solution, so as to expose the portion of the initial diffusion layer 12 located in the second region and the portion of the initial doped conductive layer 152 located in the fourth region.

[0127] The acidic solution can be a hydrofluoric acid (HF) solution, and the concentration of the HF solution can be 10%-70%, and the reaction time can be 60s. It can be understood that the removal mode and process parameters of the portion of the first glass layer 13 located in the second region and the portion of the second glass layer 16 located in the fourth region are not limited to this, and can be set as needed to meet different requirements.

[0128] After step S130, step S140 is further included: removing the portion of the initial diffusion layer located in the second region, and the portion of the initial tunneling layer and the initial doped conductive layer located in the fourth region, to form the diffusion layer, the tunneling layer and the doped conductive layer.

[0129] In some embodiments, step S140 specifically includes the following steps: using an alkaline etching solution to remove the portion of the initial diffusion layer located in the second region, and the portion of the initial tunneling layer and the initial doped conductive layer located in the fourth region, and forming a textured structure in the second region and the fourth region.

[0130] Please refer to Figure 12 Since the portion of the initial diffusion layer 12 located in the first region is covered by the first mask 20 and the first glass layer 13, and the portion of the initial doped conductive layer 152 located in the third region is covered by the second mask 30 and the second glass layer 16, the portion of the initial diffusion layer 12 located in the second region, and the portion of the initial tunneling layer 14 and the initial doped conductive layer 152 located in the fourth region can be accurately removed by using the alkaline solution, and a textured structure can be formed in the second region and the fourth region to greatly reduce the surface reflectivity.

[0131] In some embodiments, the alkaline solution is a sodium hydroxide (NaOH) solution, the concentration of the NaOH solution is 0.5%-5%, the reaction temperature is 60-80℃, the reaction time is 100-1000s, and the etching depth is 1-10um.

[0132] After step S140, step S150 of removing the part of the first glass layer in the first region and the part of the second glass layer in the third region is further included.

[0133] In some embodiments, step S150 specifically includes the following step: removing the part of the first glass layer in the first region and the part of the second glass layer in the third region by using an acidic solution.

[0134] Please refer to Figure 13 As shown in FIG. 1C, the first mask 20, the part of the first glass layer 13 in the first region, the second mask 30, and the part of the second glass layer 16 in the third region are removed by using an acidic solution, so that only the diffusion layer 121 in the first region is left on the first surface 11a of the substrate 11, and only the tunneling layer 141 and the doped conductive layer 1521 in the third region are left on the second surface 11b of the substrate 11.

[0135] The acidic solution can be a hydrofluoric acid (HF) solution, and the concentration of the HF solution can be 10%-70%, and the reaction time can be 60s. It can be understood that the removal method and process parameters of the first mask 20, the part of the first glass layer 13 in the first region, the second mask 30, and the part of the second glass layer 16 in the third region are not limited to this, and can be set as needed to meet different requirements.

[0136] The above preparation method of the solar cell can effectively improve the heat damage phenomenon of the cell and effectively improve the conversion efficiency of the cell by using photolithography to pattern the first glass layer 13 and the second glass layer 16 compared with using laser to pattern. Moreover, since the first glass layer 13 and the second glass layer 16 are patterned at the same time, the process flow is simplified, and the cell preparation cost is reduced. In addition, since part of the doped conductive layer 1521 and the tunneling layer 141 are removed, it is beneficial to reduce the light parasitic absorption, and further improve the conversion efficiency of the cell.

[0137] In a specific embodiment, the preparation method of the solar cell includes the following steps:

[0138] First, an N-type silicon wafer is provided, and the N-type silicon wafer is subjected to double-sided texturing to form a substrate 11, and then the substrate 11 is subjected to boron diffusion treatment to form an initial diffusion layer 12 and a first glass layer 13 on both sides of the substrate 11, and then the first glass layer 13 and the initial diffusion layer 12 on the second surface 11b of the substrate 11 are removed.

[0139] Then, an initial tunneling layer 14 is formed on the second surface 11b of the substrate 11, and then an initial silicon layer 15 is formed on the first glass layer 13 and the initial tunneling layer 14, respectively, and the initial silicon layer 15 is subjected to phosphorus diffusion treatment to form an initial doped conductive layer 152 on one side of the first surface 11a of the substrate 11 and a second glass layer 16.

[0140] Finally, the substrate 11 is subjected to a patterned treatment by a chain photolithography process, first, the first glass layer 13 in the second region and the second glass layer 16 in the fourth region are removed, then the initial diffusion layer 12 in the second region is continuously removed to form a diffusion layer 121, finally, the initial tunneling layer 14 in the fourth region is removed to form a tunneling layer 141, and the initial doped conductive layer 152 in the fourth region is removed to form a doped conductive layer 1521.

[0141] Please refer to Figure 13 The application further provides a solar cell prepared by the above preparation method, which comprises the substrate 11, the diffusion layer 121, the tunneling layer 141, the doped conductive layer 1521, the first electrode and the second electrode.

[0142] The substrate 11 has a rectangular flat plate structure, has a first surface 11a and a second surface 11b arranged oppositely and horizontally along the thickness direction of the substrate 11, the first surface 11a is the surface of the substrate 11 facing the back light side of the solar cell, and the second surface 11b is the surface of the substrate 11 facing the light receiving side of the solar cell.

[0143] The first surface 11a has a first region and a second region, the first region is the region provided with the first electrode, and the second region is the region of the first surface 11a except the first region. The second surface 11b has a third region and a fourth region, the third region is the region provided with the second electrode, and the fourth region is the region of the second surface 11b except the third region. The positions of the first region and the third region, and the second region and the fourth region can completely correspond or be staggered in the thickness direction of the substrate 11, which is not limited herein.

[0144] The diffusion layer 121 is arranged on the first surface 11a of the substrate 11 and located in the first region, and the first electrode is arranged on the first surface 11a of the substrate 11 and located in the second region. The tunneling layer 141 and the doped conductive layer 1521 are arranged on the second surface 11b of the substrate 11 and located in the third region, and the second electrode is arranged on the second surface 11b of the substrate 11 and located in the fourth region.

[0145] The solar cell has high conversion efficiency because the heat damage phenomenon is reduced due to the replacement of the laser patterning by the photolithography in the processing.

[0146] The application also provides a laminated cell, which comprises a top cell, an intermediate connecting layer and a bottom cell, the intermediate connecting layer being connected between the bottom cell and the top cell. The top cell is one of a perovskite cell, a cadmium telluride solar cell, a copper indium gallium selenide solar cell or a gallium arsenide solar cell, and the bottom cell is the above-mentioned solar cell. The intermediate connecting layer is usually selected from transparent materials with high refractive index, such as transparent conductive metal oxide film (ITO).

[0147] The application also provides a photovoltaic module comprising the above-mentioned solar cell or laminated cell. In some embodiments, the photovoltaic module comprises a laminate and a frame wrapped around the laminate, and the laminate comprises, in sequence along the light direction, a front plate, a first encapsulating adhesive film, the solar cell, a second encapsulating adhesive film and a back plate.

[0148] The technical features of the above-mentioned embodiments can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the present application.

[0149] The above-mentioned embodiments only express several implementation manners of the present application, and the description is specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A method for preparing a solar cell, characterized in that, include: Provide a base; The substrate has a first surface and a second surface disposed opposite to each other along its own thickness direction. The first surface has a first region and a second region, and the second surface has a third region and a fourth region. An initial diffusion layer and a first glass layer are stacked on the first surface, and an initial tunneling layer, an initial doped conductive layer, and a second glass layer are stacked on the second surface; the first glass layer is located on the side of the initial diffusion layer away from the substrate, and the second glass layer is located on the side of the initial doped conductive layer away from the initial tunneling layer. A chain-link photolithography process is used to remove the portion of the first glass layer located in the second region and the portion of the second glass layer located in the fourth region; The portion of the initial diffusion layer located in the second region, and the portions of the initial tunneling layer and the initial doped conductive layer located in the fourth region are removed to form a diffusion layer, a tunneling layer, and a doped conductive layer; Remove the portion of the first glass layer located in the first region and the portion of the second glass layer located in the third region.

2. The method for preparing a solar cell according to claim 1, characterized in that, The step of removing the portion of the initial diffusion layer located in the second region, and the portions of the initial tunneling layer and the initial doped conductive layer located in the fourth region, to form the diffusion layer, the tunneling layer, and the doped conductive layer, includes: An alkaline texturing solution is used to remove the portion of the initial diffusion layer located in the second region, as well as the portions of the initial tunneling layer and the initial doped conductive layer located in the fourth region, and a texturized structure is formed in the second region and the fourth region.

3. The method for preparing a solar cell according to claim 2, characterized in that, The alkaline texturing solution is a NaOH solution, and the concentration of the alkaline texturing solution is 0.5%-5%.

4. The method for preparing a solar cell according to claim 1, characterized in that, The step of removing the portion of the first glass layer located in the first region and the portion of the second glass layer located in the third region includes: An acidic solution is used to remove the portion of the first glass layer located in the first region and the portion of the second glass layer located in the third region.

5. The method for preparing a solar cell according to claim 4, characterized in that, The acidic solution is an HF solution, and the concentration of the acidic solution is 10%-70%.

6. The method for preparing a solar cell according to claim 1, characterized in that, The step of removing the portion of the first glass layer located in the second region and the portion of the second glass layer located in the fourth region using a chain photolithography process includes: A first mask is formed on the first glass layer, and a second mask is formed on the second glass layer; the orthographic projection of the first mask onto the substrate coincides with the first region, and the orthographic projection of the second mask onto the substrate coincides with the third region. Remove the portion of the first glass layer located in the second region and the portion of the second glass layer located in the fourth region to expose the portion of the initial diffusion layer located in the second region and the portion of the initial doped conductive layer located in the fourth region.

7. The method for preparing a solar cell according to claim 6, characterized in that, The step of removing the portion of the first glass layer located in the second region and the portion of the second glass layer located in the fourth region to expose the portion of the initial diffusion layer located in the second region and the portion of the initial doped conductive layer located in the fourth region includes: An acidic solution is used to remove portions of the first glass layer located in the second region and portions of the second glass layer located in the fourth region, to expose portions of the initial diffusion layer located in the second region and portions of the initial doped conductive layer located in the fourth region.

8. The method for preparing a solar cell according to claim 7, characterized in that, The acidic solution is an HF solution, and the concentration of the acidic solution is 10%-70%.

9. The method for preparing a solar cell according to claim 6, characterized in that, The step of forming the first mask on the first glass layer includes: Photoresist is applied to the first glass layer; A first photomask is placed on the first glass layer coated with the photoresist. The first photomask has a first cutout portion, which is disposed corresponding to the first region. The photoresist is irradiated, causing the portion of the photoresist located in the first region to deform and form the first mask. Remove the first mask; Remove the portion of the photoresist located in the second region.

10. The method for preparing a solar cell according to claim 6, characterized in that, The step of forming the second mask on the second glass layer includes: Photoresist is applied to the second glass layer; A second photomask is placed on the second glass layer coated with the photoresist. The second photomask has a second cutout portion, which is correspondingly disposed to the third region. The photoresist is irradiated, causing a portion of the photoresist located in the third region to deform and form the second mask. Remove the second mask; Remove the portion of the photoresist located in the fourth region.

11. The method for preparing a solar cell according to claim 1, characterized in that, The steps of forming an initial diffusion layer and a first glass layer stacked on the first surface, and forming an initial tunneling layer, an initial doped conductive layer, and a second glass layer stacked on the second surface include: The initial diffusion layer, the first glass layer, the doped conductive layer and the glass layer are sequentially formed on the first surface, and the initial tunneling layer, the initial doped conductive layer and the second glass layer are sequentially formed on the second surface. An alkaline solution is used to remove the doped conductive layer and the glass layer.

12. A solar cell, characterized in that, The solar cell is prepared using the solar cell preparation method as described in any one of claims 1 to 11.

13. A stacked battery, comprising a top battery and a bottom battery, characterized in that, The bottom cell is the solar cell according to claim 12.

14. A photovoltaic module, characterized in that, This includes the solar cell as described in claim 12, or the tandem cell as described in claim 13.

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