Battery preparation method and battery structure

Abstract

The invention relates to a battery preparation method and a battery structure. The cell preparation method comprises the following steps: providing an N-type silicon substrate; forming a first passivation contact structure and a second passivation contact structure which are arranged at an interval on the back surface of the N-type silicon substrate to obtain a first form body; texturing is carried out on the first form body, wet ozone or wet oxygen is introduced in the drying process of the texturing process, and a first passivation film in a silicon oxide form is formed on the front face and the back face of the first form body; and forming an electrode assembly on one side, far away from the N-type silicon substrate, of the first passivation film. Through the above arrangement, the preparation of the cell is completed, and wet ozone or wet oxygen is introduced in the drying step in the texturing passivation process to form a first passivation film in a silicon oxide form on the front surface and the back surface of the first form body, so that the surface defect density of the textured N-type silicon substrate is effectively reduced, and the surface passivation effect of the N-type silicon substrate is enhanced. And thus, higher cell conversion efficiency is obtained.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic power generation technology, and in particular to a battery preparation method and a battery structure. Background Art

[0002] A solar cell is a semiconductor device that can convert solar energy into electrical energy. Lower cost per kilowatt-hour has always been the goal pursued by the solar cell industry.

[0003] Current solar cells combine TOPCon technology with IBC technology. By combining the high short-circuit current of IBC technology with the excellent passivation contact characteristics of TOPCon technology, a cross-finger-shaped graphic structure is formed on the back of the solar cell. Such a structure can improve the conversion efficiency of the cell through a good passivation structure. However, the back passivation effect of current solar cells is poor, which limits the conversion efficiency of the cell. Summary of the invention

[0004] Based on this, it is necessary to provide a battery preparation method and battery structure to address the problem that the back side passivation effect of current solar cells is poor, resulting in limited conversion efficiency of the battery.

[0005] A battery preparation method, the battery preparation method comprising the following steps:

[0006] Providing an N-type silicon substrate;

[0007] forming a first passivation contact structure and a second passivation contact structure spaced apart from each other on the back side of the N-type silicon substrate to obtain a first morphology body;

[0008] Performing texturing on the first body, introducing wet ozone or wet oxygen in a drying step of the texturing process to form a first passivation film in the form of silicon oxide on the front and back sides of the first body;

[0009] An electrode assembly is formed on a side of the first passivation film away from the N-type silicon substrate.

[0010] In one of the embodiments, the humidity in the wet ozone or the wet oxygen is 30%-70%.

[0011] In one embodiment, the temperature range of the drying process is 90°-200°.

[0012] In one embodiment, after “texturing the first form body, introducing wet ozone or wet oxygen in the drying process of the texturing process to form a first passivation film in the form of silicon oxide on the front and back sides of the first form body” and before “forming an electrode assembly on a side of the first passivation film away from the N-type silicon substrate”, the method further includes:

[0013] A second passivation film is formed on a surface of the first passivation film.

[0014] In one embodiment, the second passivation film includes at least one of aluminum oxide, silicon nitride, and silicon oxynitride.

[0015] In one embodiment, the step of “texturing the first body, introducing wet ozone or wet oxygen in a drying process of the texturing process to form a first passivation film in the form of silicon oxide on the front and back surfaces of the first body” specifically includes the following steps:

[0016] Performing acid etching on the front surface of the first morphological body to expose the front morphology of the N-type silicon substrate;

[0017] Performing front texturing on the first morphological body, and etching a spacing region between the first passivation contact structure and the second passivation contact structure at the same time, so as to form a pyramid texture surface in the spacing region;

[0018] Cleaning and drying the first body after texturing to obtain the first passivation film;

[0019] A second passivation film is formed on the surface of the first passivation film to obtain a semi-finished product.

[0020] In one embodiment, the step of “cleaning and drying the first body after texturing to obtain the first passivation film” specifically includes the following steps:

[0021] Washing away chemical residues on the first form with pure water;

[0022] Slowly pulling the first body with pure water to ensure that the surface of the first body is clean;

[0023] The clean first-form body is dried by a drying device, and wet ozone or wet oxygen is introduced during or after the drying process to form the first passivation film in the form of silicon oxide on the front and back sides of the first-form body.

[0024] In one embodiment, in the step of “forming a first passivation contact structure and a second passivation contact structure spaced apart from each other on the back side of the N-type silicon substrate to obtain a first morphological body”, the following steps are specifically included:

[0025] Depositing a first tunneling oxide layer and a first polysilicon layer in sequence on the back side of the N-type silicon substrate;

[0026] performing boron diffusion on the first polysilicon layer and forming a borosilicate glass layer on the first polysilicon layer;

[0027] Removing a portion of the borosilicate glass layer through a first patterning process, wherein the area where the borosilicate glass layer is removed is an N area;

[0028] The N region is etched to expose the morphology of the N-type silicon substrate corresponding to the N region, thereby obtaining an initial morphology.

[0029] In one embodiment, after “etching the N region to expose the morphology of the N-type silicon substrate corresponding to the N region, thereby obtaining an initial morphology”, the following steps are also included:

[0030] Depositing a second tunnel oxide layer and a second polysilicon layer in sequence on the outer layer of the initial form;

[0031] Diffusion of phosphorus into the second polysilicon layer and formation of a phosphorus-silicate glass layer on the second polysilicon layer;

[0032] A second patterning process is performed on the first tunneling oxide layer, the first polysilicon layer, the second tunneling oxide layer and the second polysilicon layer to form the first passivation contact structure and the second passivation contact structure which are spaced apart.

[0033] The above-mentioned battery preparation method completes the preparation of the battery through the doping process, the texturing passivation process and the metallization preparation process. In addition, by introducing wet ozone or wet oxygen in the drying step of the texturing passivation process to form a first passivation film in the form of silicon oxide on the front and back of the first form body, the surface defect density of the N-type silicon substrate after texturing is effectively reduced, and the surface passivation effect of the N-type silicon substrate is enhanced, thereby obtaining a higher battery conversion efficiency.

[0034] The present application also provides a battery structure prepared by the battery preparation method described in any of the above embodiments, the battery structure comprising:

[0035] An N-type silicon substrate has a front side and a back side that are arranged opposite to each other, a doping layer is distributed on the back side of the N-type silicon substrate, and the doping layer includes a first deposition area, a second deposition area and a spacing area therebetween;

[0036] A pyramid velvet surface formed on the front surface of the N-type silicon substrate and the spacing area;

[0037] A passivation layer, comprising a first passivation film covering the pyramid velvet surface and the doping layer, wherein the first passivation film is silicon oxide;

[0038] The electrode assembly comprises a first electrode and a second electrode, wherein the first electrode contacts the first deposition area through the passivation layer on the back side, and the second electrode contacts the second deposition area through the passivation layer on the back side. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is a flowchart of the battery preparation method provided in the present application.

[0040] FIG. 2 is a schematic diagram of the structure of the preparation process of the initial form provided in the present application.

[0041] FIG. 3 is a schematic diagram of the structure of the preparation process of the first form provided in the present application.

[0042] FIG4 is a schematic diagram of the structure of the preparation process of the semi-finished product provided in the present application.

[0043] FIG5 is a schematic diagram of a first passivation film preparation device provided in the present application.

[0044] FIG. 6 is a schematic diagram of a battery structure provided in the present application.

[0045] in:

[0046] 10. Battery structure; 20. First passivation film preparation device; 21. Ozone generator; 22. Water tank; 23. Defoaming device; 30. Drying device; 40. First form; 50. Initial form; 60. Semi-finished product;

[0047] 100, N-type silicon substrate; 110, front side; 120, back side;

[0048] 200, doping layer; 210, first deposition area; 211, first tunneling oxide layer; 212, first polysilicon layer; 2121, borosilicate glass layer; 220, second deposition area; 221, second tunneling oxide layer; 222, second polysilicon layer; 2221, phosphosilicate glass layer; 230, spacing area;

[0049] 300, pyramid suede;

[0050] 400, passivation layer; 410, first passivation film; 420, second passivation film;

[0051] 500, electrode assembly; 510, first electrode; 520, second electrode. DETAILED DESCRIPTION

[0052] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0053] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0054] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0055] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0056] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0057] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0058] Referring to Figures 1, 2, 3 and 4, Figure 1 shows a flow chart of a battery preparation method in an embodiment of the present application, Figure 2 shows a schematic diagram of the preparation process structure of an initial form in an embodiment of the present application, Figure 3 shows a schematic diagram of the preparation process structure of a first form in an embodiment of the present application, and Figure 4 shows a schematic diagram of the preparation process structure of a semi-finished product provided in an embodiment of the present application.

[0059] A battery preparation method provided in an embodiment of the present application comprises the following steps:

[0060] Step S1, providing an N-type silicon substrate 100. When specifically configured, the N-type silicon substrate 100 has a front side 110 and a back side 120 that are relatively configured. The front side 110 is used to face the sun, i.e., the light-receiving side, and the back side 120 is used to face away from the sun, i.e., the backlight side. When specifically used, both the front side 110 and the back side 120 of the N-type silicon substrate 100 are polished;

[0061] Step S2, forming a first passivation contact structure and a second passivation contact structure spaced apart on the back surface 120 of the N-type silicon substrate 100 to obtain the first form body 40 shown in FIG. 3 . In the specific configuration, the first passivation contact structure and the second passivation contact structure are generally formed by a doping process, and the first passivation contact structure and the second passivation contact structure have a better passivation effect on the N-type silicon substrate 100, thereby improving the photoelectric conversion efficiency of the formed solar cell;

[0062] Step S3, referring to FIG. 4 , the first form body 40 is textured, and wet ozone or wet oxygen is introduced in the drying process of the texture process to form a first passivation film 410 in the form of silicon oxide on the front side 110 and the back side 120 of the first form body 40. Through the above arrangement, the oxidizing ability of wet ozone or wet oxygen is utilized to form silicon oxide on the front side 110 and the back side 120 of the first form body 40, so as to enhance the passivation effect on the surface of the N-type silicon substrate and reduce the defect density on the surface of the N-type silicon substrate after the texture process;

[0063] Step S4, forming an electrode assembly on a side of the first passivation film 410 away from the N-type silicon substrate 100 to complete the preparation of the battery.

[0064] The above-mentioned battery preparation method completes the preparation of the battery through the doping process, the texturing passivation process and the metallization preparation process. In addition, by introducing wet ozone or wet oxygen in the drying step of the texturing passivation process to form a first passivation film 410 in the form of silicon oxide on the front 110 and the back 120 of the first form body 40, the surface defect density of the N-type silicon substrate after texturing is effectively reduced, and the surface passivation effect of the N-type silicon substrate is enhanced, thereby obtaining a higher battery conversion efficiency.

[0065] Taking wet ozone as an example, in order to more conveniently implement the introduction of wet ozone in the drying process of the texturing process, an embodiment of the present application provides a first passivation film preparation device 20 as shown in Figure 5. The first passivation film preparation device 20 includes an ozone generator 21, a water tank 22 and a defoaming device 23 that are connected in sequence. When specifically set, the defoaming device 23 is connected to the drying device 30, and the drying device 30 is provided with a first form body 40. When used specifically, oxygen is introduced into the ozone generator 21 to generate ozone. The ozone passes through the water tank 22 so that part of the ozone is dissolved in the water in the water tank 22. The part that is not dissolved in water is collected by the defoaming device 23 and enters the drying device 30. The defoaming device 23 is used to filter the water vapor of the wet ozone so that the wet ozone retains the set humidity before entering the drying device 30.

[0066] In order to form a dense first passivation film 410, a preferred embodiment is that the humidity in the wet ozone or wet oxygen accounts for 30%-70%. It should be noted that the above percentage is obtained by the applicant after repeated experiments. When the humidity in the wet ozone or wet oxygen accounts for 30%-70%, a dense first passivation film 410 is formed on the surface of the first form body 40, and the thickness of the first passivation film 410 ranges from 0.01nm to 1nm, so as to enhance the passivation effect on the surface of the N-type silicon substrate and reduce the defect density on the surface of the N-type silicon substrate after texturing.

[0067] It should be emphasized that ozone decomposes less at low temperatures and has strong oxidation ability; as the oxidation temperature increases, on the one hand, the ozone decomposition is enhanced, resulting in a weakened oxidation ability, which reduces the thickness of the first passivation film 410. On the other hand, as the ozone decomposition is enhanced, the number of oxygen atoms increases. When the oxidation temperature continues to increase, the oxygen atoms that do not participate in the reaction participate in the oxidation, and the thickness of the first passivation film 410 increases. In order to form a first passivation film 410 of appropriate thickness to enhance the passivation effect, a preferred embodiment is that the temperature range of the drying process is 90°-200°. In the specific setting, the drying time is set between 500s-900s, and the ozone concentration range is between 0.5ppm-10ppm. Through the above setting, a first passivation film 410 with a thickness range of 0.01nm-1nm will be formed on the surface of the first form body 40 to enhance the passivation effect on the surface of the N-type silicon substrate and reduce the defect density of the surface of the N-type silicon substrate after texturing.

[0068] Referring to FIG. 4 again, in order to further enhance the passivation effect, a preferred embodiment, after step S3 and before step S4, further includes forming a second passivation film 420 on the surface of the first passivation film 410. In a specific configuration, the second passivation film 420 includes at least one of aluminum oxide, silicon nitride, and silicon oxynitride. It should be emphasized that when the second passivation film 420 is selected as aluminum oxide, aluminum oxide can be deposited on the surface of the first passivation film 410 using ALD deposition technology. The first passivation film 410 of silicon oxide can promote the release of the field passivation effect of the second passivation film 420, thereby combining the advantages of both in terms of passivation performance, obtaining a relatively low defect state, and improving the open circuit voltage of the battery, thereby obtaining a higher battery conversion efficiency.

[0069] Please refer to FIG. 2 . In order to conveniently prepare the initial form 50 so as to prepare the first form later, a preferred embodiment, in step S2, specifically includes the following steps:

[0070] Step S21, depositing a first tunnel oxide layer 211 and a first polysilicon layer 212 on the back side 120 of the N-type silicon substrate 100 in sequence. In the specific operation, the polished N-type silicon substrate 100 is passed through a deposition device to deposit the first tunnel oxide layer 211, and then the first polysilicon layer 212 is deposited on the surface of the first tunnel oxide layer 211, wherein the thickness of the first tunnel oxide layer 211 is preferably 1.2nm-2nm, and the thickness of the first polysilicon layer 212 is preferably 100nm-400nm; through step S22, boron is diffused on the first polysilicon layer 212, and a borosilicate glass layer 212 is formed on the first polysilicon layer 212. 121, the thickness of the borosilicate glass layer 2121 is preferably 30nm-100nm. In specific operations, boron diffusion can be carried out in a high-temperature diffusion device; step S23, a first graphical treatment is performed to remove part of the borosilicate glass layer 2121, and the area where the borosilicate glass layer 2121 is removed is the N area. In specific settings, the borosilicate glass layer 2121 in the N area can be removed by laser, and the area between two adjacent N areas is the P area; step S24, etching the N area to expose the morphology of the N-type silicon substrate 100 corresponding to the N area, thereby obtaining an initial morphology 50. In specific settings, the N area can be etched by alkali polishing.

[0071] As shown in FIG. 3 , in order to conveniently prepare the first form body 40 from the initial form body 50 , specifically, after step S24 , the following steps are further included:

[0072] Step S24, sequentially depositing a second tunneling oxide layer 221 and a second polysilicon layer 222 on the outer layer of the initial form 50, so as to deposit a second polysilicon layer 222 on the surface of the second tunneling oxide layer 221, wherein the thickness of the second tunneling oxide layer 221 is preferably 1.2nm-2nm, and the thickness of the second polysilicon layer 222 is preferably 100nm-400nm; through step S24, phosphorus is diffused on the second polysilicon layer 222, and a phosphosilicate glass layer 2221 is formed on the second polysilicon layer 222, and the thickness of the phosphosilicate glass layer 2221 is preferably 30nm-100nm; through step S24, The first tunnel oxide layer 211, the first polysilicon layer 212, the second tunnel oxide layer 221 and the second polysilicon layer 222 are subjected to a second patterning treatment to form a first passivation contact structure and a second passivation contact structure that are spaced apart. The second patterning treatment may be laser, and specifically, laser may be used to remove the phosphosilicate glass layer 2221 corresponding to all P regions and the phosphosilicate glass layer 2221 corresponding to part of the N region, so that there is a spacing region 230 between the borosilicate glass layer 2121 and the phosphosilicate glass layer 2221, corresponding to the gap between the first passivation contact structure and the second passivation contact structure, thereby obtaining a first morphological body 40.

[0073] It should be emphasized that the velvet structure can increase the surface area of ​​the cell, thereby increasing the generation and collection of photogenerated carriers and improving the conversion efficiency of the cell. In conjunction with FIG4 , in order to more conveniently perform velvet on the first form body 40 , a preferred implementation, in step S3 , specifically includes the following steps:

[0074] Step S31, acid etching is performed on the front surface 110 of the first form body 40 to expose the morphology of the front surface 110 of the N-type silicon substrate 100. Through the above setting, the wrap-around plating inevitably formed on the front surface 110 of the N-type silicon substrate 100 in step S2 is eliminated. In the specific setting, the acid etching is performed after mixing three solutions of nitric acid, hydrofluoric acid and sulfuric acid, wherein the range of nitric acid is 300g / L-400g / L, the range of hydrofluoric acid is 50g / L-100g / L, and the range of sulfuric acid is 60g / L-150g / L;

[0075] Step S32, the front surface 110 of the first form body 40 is textured, and the spacing area between the first passivation contact structure and the second passivation contact structure is etched at the same time, so as to form a pyramid velvet surface 300 in the spacing area. In the specific operation: first, sodium hydroxide and hydrogen peroxide are used to pre-clean the first form body 40 after acid etching; then, chemical residues on the first form body 40 are washed clean by water; then, sodium hydroxide and additives are used to form a pyramid velvet surface 300 structure on the front surface 110 of the first form body 40 and the spacing area between the first passivation contact structure and the second passivation contact structure, and at the same time, the corresponding second tunneling oxide layer and the second polysilicon layer 222 on the P region are removed; in order to ensure the smooth progress of the subsequent coating process, the chemical residues are washed clean by pure water, and then sodium hydroxide and hydrogen peroxide are used to react with the additives to clean the surface of the first form body 40, and then pickling is performed by hydrofluoric acid aqueous solution to remove the borosilicate glass layer 2121 in the P region and the phosphorus silicon glass layer 2221 in the N region, so that the surface is cleaner;

[0076] It should be noted that the texturing process in step S32 involves acidic and alkaline solutions. Therefore, after the pyramid velvet surface 300 is formed, the first form body 40 after texturing will be cleaned and dried through step S33. In the specific cleaning process: chemical residues on the first form body 40 are washed away by pure water; the first form body 40 is then slowly pulled with pure water to ensure that the surface of the first form body 40 is clean; in the specific drying process: by introducing wet ozone or wet oxygen, a first passivation film 410 in the form of silicon oxide is formed on the front side 110 and the back side 120 of the first form body 40 simply and quickly, which can effectively reduce the surface defect density of the N-type silicon substrate after texturing and enhance the surface passivation effect of the N-type silicon substrate. In addition, wet ozone or wet oxygen can be introduced after drying the first form body 40 to form the first passivation film 410;

[0077] In order to enhance the passivation effect, a second passivation film 420 is formed on the surface of the first passivation film 410 through step S34. The second passivation film 420 can be aluminum oxide. Through the above configuration, the first passivation film 410 in the form of silicon oxide can promote the release of the aluminum oxide field passivation effect, thereby combining the advantages of both in terms of passivation performance, obtaining a relatively low defect state, and improving the open circuit voltage of the battery, thereby obtaining a higher battery conversion efficiency. In the specific configuration, the thickness of the second passivation film 420 can be selected to be 6nm.

[0078] It should be noted that after the second passivation film 420 is formed on the surface of the first passivation film 410, the semi-finished product 60 is obtained. Subsequently, silver paste can be screen-printed to form an ohmic contact for facilitating current extraction, and then the battery is obtained through sintering.

[0079] The present application also provides a battery structure 10 prepared by the battery preparation method described in any of the above embodiments, as shown in Figure 6, which shows a schematic diagram of the battery structure 10 in an embodiment of the present application. The above battery structure 10 includes an N-type silicon substrate 100, a pyramid velvet surface 300, a passivation layer 400 and an electrode assembly 500.

[0080] The N-type silicon substrate 100 has a front side 110 and a back side 120 that are arranged opposite to each other. A doping layer 200 is distributed on the back side 120 of the N-type silicon substrate 100. The doping layer 200 includes a first deposition area 210, a second deposition area 220, and a spacing area 230 therebetween. In a specific configuration, the first deposition area 210 includes a first tunneling oxide layer 211 and a boron-doped first polysilicon layer 212, and the second deposition area 220 includes a second tunneling oxide layer 221 and a phosphorus-doped second polysilicon layer 222. The pyramid velvet surface 300 is formed on the front side 110 and the spacing area 230 of the N-type silicon substrate 100.

[0081] The passivation layer 400 includes a first passivation film 410 covering the pyramid velvet surface 300 and the doping layer 200. The first passivation film 410 is silicon oxide. In a specific setting, the passivation layer 400 also includes a second passivation film 420. The second passivation film 420 covers the outer side of the first passivation film 410. The second passivation film 420 can be selected as aluminum oxide. Through the above setting, the first passivation film 410 of silicon oxide can promote the release of the field passivation effect of the second passivation film 420, thereby combining the advantages of both in terms of passivation performance, obtaining a relatively low defect state, and improving the open circuit voltage of the battery, thereby obtaining a higher battery conversion efficiency.

[0082] The electrode assembly 500 includes a first electrode 510 and a second electrode 520. The first electrode 510 passes through the passivation layer 400 located on the back side 120 and contacts the first deposition area 210. The second electrode 520 passes through the passivation layer 400 located on the back side 120 and contacts the second deposition area 220. In a specific configuration, one end of the first electrode 510 contacts the boron-doped first polysilicon layer 212 in the first deposition area 210, and the other end passes through the first deposition area 210; one end of the second electrode 520 contacts the phosphorus-doped second polysilicon layer 222 in the second deposition area 220, and the other end passes through the second deposition area 220.

[0083] The battery structure 10 is provided with a first passivation film 410 covering the pyramid velvet surface 300 and the doping layer 200. The first passivation film 410 is silicon oxide, which enhances the surface passivation effect of the N-type silicon substrate 100, thereby obtaining a higher battery conversion efficiency.

[0084] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for preparing a battery, characterized in that: The battery preparation method comprises the following steps: Providing an N-type silicon substrate; forming a first passivation contact structure and a second passivation contact structure spaced apart from each other on the back side of the N-type silicon substrate to obtain a first morphology body; Performing texturing on the first body, introducing wet ozone or wet oxygen in a drying step of the texturing process to form a first passivation film in the form of silicon oxide on the front and back sides of the first body; An electrode assembly is formed on a side of the first passivation film away from the N-type silicon substrate.

2. The battery preparation method according to claim 1, characterized in that: The humidity in the wet ozone or the wet oxygen is 30%-70%.

3. The battery preparation method according to claim 1, characterized in that: The temperature range of the drying process is 90°-200°.

4. The battery preparation method according to claim 1, characterized in that: After the step of "texturing the first body, introducing wet ozone or wet oxygen in the drying process of the texturing process to form a first passivation film in the form of silicon oxide on the front and back sides of the first body", and before the step of "forming an electrode assembly on a side of the first passivation film away from the N-type silicon substrate", the method further includes: A second passivation film is formed on a surface of the first passivation film.

5. The battery preparation method according to claim 4, characterized in that: The second passivation film includes at least one of aluminum oxide, silicon nitride, and silicon oxynitride.

6. The battery preparation method according to claim 1, characterized in that: In the step of "texturing the first body, introducing wet ozone or wet oxygen in the drying process of the texturing process to form a first passivation film in the form of silicon oxide on the front and back sides of the first body", the following steps are specifically included: Performing acid etching on the front surface of the first morphological body to expose the front morphology of the N-type silicon substrate; Performing front texturing on the first morphological body, and etching a spacing region between the first passivation contact structure and the second passivation contact structure at the same time, so as to form a pyramid texture surface in the spacing region; Cleaning and drying the first body after texturing to obtain the first passivation film; A second passivation film is formed on the surface of the first passivation film to obtain a semi-finished product.

7. The battery preparation method according to claim 6, characterized in that: In the step of “cleaning and drying the first morphological body after texturing to obtain the first passivation film”, the following steps are specifically included: Washing away chemical residues on the first form with pure water; Slowly pulling the first body with pure water to ensure that the surface of the first body is clean; The clean first-form body is dried by a drying device, and wet ozone or wet oxygen is introduced during or after the drying process to form the first passivation film in the form of silicon oxide on the front and back sides of the first-form body.

8. The battery preparation method according to claim 1, characterized in that: In the “forming a first passivation contact structure and a second passivation contact structure spaced apart from each other on the back side of the N-type silicon substrate to obtain a first morphological body”, the following steps are specifically included: Depositing a first tunneling oxide layer and a first polysilicon layer in sequence on the back side of the N-type silicon substrate; performing boron diffusion on the first polysilicon layer and forming a borosilicate glass layer on the first polysilicon layer; Removing a portion of the borosilicate glass layer through a first patterning process, wherein the area where the borosilicate glass layer is removed is an N area; The N region is etched to expose the morphology of the N-type silicon substrate corresponding to the N region, thereby obtaining an initial morphology.

9. The battery preparation method according to claim 8, characterized in that: After the step of “etching the N region to expose the morphology of the N-type silicon substrate corresponding to the N region, thereby obtaining an initial morphology”, the following steps are also included: Depositing a second tunnel oxide layer and a second polysilicon layer in sequence on the outer layer of the initial form; Diffusion of phosphorus into the second polysilicon layer and formation of a phosphorus-silicate glass layer on the second polysilicon layer; A second patterning process is performed on the first tunneling oxide layer, the first polysilicon layer, the second tunneling oxide layer and the second polysilicon layer to form the first passivation contact structure and the second passivation contact structure which are spaced apart.

10. A battery structure prepared by the battery preparation method according to any one of claims 1 to 9, characterized in that: The battery structure comprises: An N-type silicon substrate has a front side and a back side that are arranged opposite to each other, a doping layer is distributed on the back side of the N-type silicon substrate, and the doping layer includes a first deposition area, a second deposition area and a spacing area therebetween; A pyramid velvet surface formed on the front surface of the N-type silicon substrate and the spacing area; A passivation layer, comprising a first passivation film covering the pyramid velvet surface and the doping layer, wherein the first passivation film is silicon oxide; The electrode assembly comprises a first electrode and a second electrode, wherein the first electrode contacts the first deposition area through the passivation layer on the back side, and the second electrode contacts the second deposition area through the passivation layer on the back side.

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