Heterojunction cell preparation method, heterojunction cell and photovoltaic module
By using spherical copper powder as conductive paste in the preparation of heterojunction batteries, the problems of poor contact performance between silver paste and back surface and mesh breaking are solved, and efficient metal electrode curing and contact are achieved, and production efficiency is improved. Battery performance.
Patent Information
- Application Number
- CN202411301178.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-18
- Publication Date
- 2024-12-17
AI Technical Summary
During the preparation of heterojunction batteries, when printing with sheet silver powder, it is easy to cause poor contact performance between the silver paste and the back surface or the screen printing screen to be broken, resulting in a decrease in production efficiency and an increase in material costs.
Spherical copper powder is used as conductive paste, and printed on the surface of the transparent conductive layer away from the substrate by screen printing, and curing at a preset temperature to form an alloy between the metal electrode and the transparent conductive layer to avoid breaking the screen and Improve contact performance.
It effectively avoids the damage of the screen printing screen, ensures good contact between the conductive layer and the transparent conductive layer, reduces the risk of crystallization, improves production efficiency and controls material costs.
Smart Images
Figure CN119153556A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of solar cells, and specifically provides a method for preparing a heterojunction cell, a heterojunction cell and a photovoltaic module. Background Art
[0002] Heterojunction cells have a series of advantages such as high conversion efficiency, fewer manufacturing processes, and thin-film applications. The existing mass-produced structures have velvet structures on both the front and back sides, and the conversion efficiency can still be further improved in the use scenario where the front side is mainly illuminated. In response to this, the existing technology uses the back side of the HJT (Heterojunction) cell to be processed into a fully polished surface or a microstructure with a polished surface to further improve the cell reflectivity and improve the front efficiency.
[0003] Usually, in the process of preparing heterojunction batteries, silver paste is used as a conductive paste and a screen printing process is used to prepare metal electrodes. However, when the back surface of the battery has a planar microstructure, the method of using silver paste to prepare the metal electrode through a screen printing process is prone to problems such as poor contact between the silver paste and the back surface or puncture of the screen printing screen, resulting in a decrease in production efficiency and an increase in material costs. Summary of the invention
[0004] The present application aims to solve the above technical problem, that is, to solve the problem that in the existing heterojunction battery preparation process, when flaky silver powder is used for printing on a flat back surface, it is impossible to avoid crystallization and form good contact while avoiding piercing the screen printing screen.
[0005] In a first aspect, the present application provides a method for preparing a heterojunction battery, which comprises:
[0006] Sequentially preparing a first intrinsic passivation layer, a first doping layer and a first transparent conductive layer on a first side surface of the substrate;
[0007] Using spherical copper powder as conductive paste, printing the conductive paste on the surface of the first transparent conductive layer away from the substrate by screen printing;
[0008] The conductive paste printed on the first transparent conductive layer is cured for a preset time at a preset temperature to obtain a first metal electrode, wherein an alloy is formed at a contact interface between the first metal electrode and the first transparent conductive layer.
[0009] In some embodiments, the preset temperature is 250-300° C., and the preset time is 5-15 seconds.
[0010] In some embodiments, the method further comprises:
[0011] A second intrinsic passivation layer, a second doping layer, a second transparent conductive layer and a second metal electrode are sequentially prepared on the second side surface of the substrate.
[0012] In some embodiments, preparing the second metal electrode comprises:
[0013] Using spherical copper powder as conductive paste, printing the conductive paste on the surface of the second transparent conductive layer away from the substrate by screen printing;
[0014] At the preset temperature, the conductive paste printed on the second transparent conductive layer is cured for the preset time to obtain a second metal electrode.
[0015] In some embodiments, the first metal electrode is partially embedded in the first transparent conductive layer.
[0016] In some embodiments, before sequentially preparing the first intrinsic passivation layer, the first doping layer, and the first transparent conductive layer on the first side surface of the substrate, the method further includes:
[0017] Texturing the first side surface and the second side surface of the substrate;
[0018] At least a portion of the first side surface after texturing is planarized.
[0019] In some embodiments, after obtaining the first metal electrode, the method further includes: forming an anti-oxidation layer on a surface of the first metal electrode.
[0020] In some embodiments, the anti-oxidation layer includes at least one of silver, tin, and nickel.
[0021] In some embodiments, a diameter of the spherical copper powder is smaller than a width of the first metal electrode.
[0022] In a second aspect, the present application provides a heterojunction battery, which includes a substrate, a first intrinsic passivation layer, a first doping layer, a first transparent conductive layer and a first metal electrode prepared in sequence on the first side surface of the substrate, wherein the first metal electrode is prepared using spherical copper powder as a conductive paste, and an alloy is formed at the contact interface between the first metal electrode and the first transparent conductive layer.
[0023] In a third aspect, the present application provides a photovoltaic module, which includes the heterojunction cell described above.
[0024] In the case of adopting the above technical solution, the present application can provide a method for preparing a heterojunction battery, by sequentially preparing a first intrinsic passivation layer, a first doping layer and a first transparent conductive layer on the first side surface of the substrate; using spherical copper powder as a conductive paste, and using screen printing to print the conductive paste on the side surface of the first transparent conductive layer away from the substrate; at a preset temperature, the conductive paste printed on the first transparent conductive layer is cured for a preset time to obtain a first metal electrode, wherein the contact interface between the first metal electrode and the first transparent conductive layer forms an alloy. The spherical structure can avoid damage to the screen printing screen. In addition, using copper powder as a conductive paste, it can be cured at a lower preset temperature and in a shorter preset time, which can avoid the crystallization of the amorphous silicon structure and further influence on the heterojunction battery. At the same time, during the curing process, the conductive paste can be partially embedded in the first transparent conductive layer and form an alloy with the first transparent conductive layer, thereby forming a good contact with the first transparent conductive layer. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings, in which:
[0026] Figure 1 It is a schematic diagram of the process of preparing a heterojunction battery provided in an embodiment of the present application;
[0027] Figure 2 is a schematic diagram of the structure obtained after executing step S11;
[0028] Figure 3 is a schematic diagram of the structure obtained after executing step S13;
[0029] Figure 4 is a schematic flow chart of a method for preparing a heterojunction battery provided by another embodiment of the present application;
[0030] Figure 5 is a schematic structural diagram obtained after executing step S41;
[0031] Figure 6 is a schematic structural diagram obtained after executing step S42;
[0032] Figure 7 is a schematic diagram of the structure obtained after executing step S45;
[0033] Figure 8 It is a schematic diagram of the heterojunction battery structure provided in one embodiment of the present application. DETAILED DESCRIPTION
[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.
[0035] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. The words "include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.
[0036] Based on the description of the background technology section, it can be known that in the process of preparing heterojunction batteries, silver paste is usually used as a conductive paste and a screen printing process is used to prepare metal electrodes. Among them, the heterojunction battery has a structure of microcrystalline silicon / amorphous silicon, which will crystallize during high temperature. Therefore, the screen printing process in the process of preparing heterojunction batteries can only use a low-temperature silver paste solution. The main components of low-temperature silver paste are silver powder, organic matter and resin. When it contacts the velvet structure, the ball powder in the silver paste can be located at the edge and side of the pyramid velvet, forming a good contact with the velvet structure. However, when the back surface becomes a microstructure with a plane, the contact performance of the ball powder with the plane is extremely poor. In view of this, the related art uses relatively larger flaky silver powder to assist in contact, but the use of flaky silver powder greatly increases the possibility of the screen printing screen being punctured, resulting in a decrease in production efficiency and an increase in material costs. In view of this, the present application provides a method for preparing a heterojunction battery.
[0037] See also Figure 1 As shown, Figure 1 : is a schematic flow chart of a heterojunction battery preparation method provided in an embodiment of the present application, which may include:
[0038] Step S11: sequentially preparing a first intrinsic passivation layer, a first doping layer and a first transparent conductive layer on a first side surface of the substrate;
[0039] Step S12: using spherical copper powder as conductive paste, and printing the conductive paste on the surface of the first transparent conductive layer away from the substrate by screen printing;
[0040] Step S13: curing the conductive paste printed on the first transparent conductive layer for a preset time at a preset temperature to obtain a first metal electrode, wherein an alloy is formed at a contact interface between the first metal electrode and the first transparent conductive layer.
[0041] In some embodiments, step S11 may specifically be to sequentially prepare a first intrinsic passivation layer 12, a first doping layer 13 and a first transparent conductive layer 14 on the first side surface S1 of the substrate 11 by using a coating process. Figure 2 As shown in the figure, the coating process may include chemical vapor deposition or physical vapor deposition.
[0042] In some embodiments, the first side surface S1 may be the surface on the backlight side of the substrate 11, so as to facilitate the subsequent preparation of a first metal electrode 15 with good contact on the surface on the backlight side of the substrate 11, thereby avoiding the influence of the contact of the first metal electrode 15 on the contact when there is a planar microstructure.
[0043] In some embodiments, the substrate 11 may be made of silicon.
[0044] The first intrinsic passivation layer 12 may be amorphous. In some embodiments, the first intrinsic passivation layer 12 may be intrinsic amorphous silicon. In some embodiments, the first intrinsic passivation layer 12 may have a thickness of 0.5 to 5 nm to effectively cover defects on the surface of the substrate 11 and improve the passivation effect without affecting the electron transmission effect.
[0045] In some embodiments, the first doping layer 13 may be N-type or P-type doped amorphous silicon. When the substrate 11 is an N-type doped silicon substrate 11, the first doping layer 13 may be a P-type doping layer, which may be boron-doped amorphous silicon or boron-doped microcrystalline silicon. In some embodiments, the thickness of the first doping layer 13 may be 10 to 50 nm to prevent light from being absorbed by the doping layer and affecting the power generation effect of the solar cell.
[0046] In some embodiments, the first transparent conductive layer 14 may be made of indium tin oxide (ITO) or other transparent conductive oxides (TCO). In some embodiments, the first transparent conductive layer 14 may be made of at least one of indium oxide, tin oxide, and zinc oxide. In some embodiments, the thickness of the first transparent conductive layer 14 may be 70-120 nm to optimize the propagation path of light inside the battery and improve light absorption efficiency.
[0047] In an embodiment of the present application, the diameter of the spherical copper powder may be smaller than the width of the first metal electrode 15. In some embodiments, the diameter of the spherical copper powder may be 200 nm-1.2 μm, and may have good fluidity and adhesion, form good physical contact with the first transparent conductive layer 14, and have good conductivity.
[0048] In the embodiments of the present application, the spherical shape can be a perfect sphere or a quasi-spherical shape. The perfect sphere refers to a particle morphology whose shape, size and surface quality strictly conform to the geometric definition of a sphere. The quasi-spherical shape refers to a particle shape that is close to a sphere as a whole, but may have certain irregularities, such as slight depressions, protrusions or edges.
[0049] In some embodiments, step S13 may specifically be curing the conductive paste printed on the first transparent conductive layer 14 at a preset temperature of 250-300° C. for a preset time of 5-15 seconds to obtain the first metal electrode 15 .
[0050] Spherical copper powder as a conductive paste can avoid damaging the screen printing screen, and copper powder has a certain burn-through property, and can be cured at a lower preset temperature to form an alloy at the interface with the first transparent conductive layer 14, thereby avoiding the influence of the planar microstructure and forming a good contact with the first transparent conductive layer 14. At the same time, the curing can be set within a shorter preset time to avoid crystallization of the amorphous silicon structure in the battery. Figure 3 As shown, Figure 3 is a schematic diagram of the structure obtained after executing step S13 , wherein, after curing at a preset temperature for a preset time, the first metal electrode 15 can be partially embedded in the first transparent conductive layer 14 .
[0051] As an example, the contact interface between the first metal electrode 15 and the first transparent conductive layer 14 may form a copper-tin alloy.
[0052] In some embodiments, a second intrinsic passivation layer, a second doping layer, a second transparent conductive layer and a second metal electrode may be sequentially formed on a second side surface S2 opposite to the first side surface S1.
[0053] The above is a method for preparing a heterojunction battery provided by an embodiment of the present application, wherein a first intrinsic passivation layer 12, a first doping layer 13 and a first transparent conductive layer 14 are sequentially prepared on the first side surface S1 of the substrate 11; spherical copper powder is used as a conductive paste, and the conductive paste is printed on the side surface of the first transparent conductive layer 14 away from the substrate 11 by screen printing; at a preset temperature, the conductive paste printed on the first transparent conductive layer 14 is cured for a preset time to obtain a first metal electrode 15, wherein the contact interface between the first metal electrode 15 and the first transparent conductive layer 14 forms an alloy. The spherical structure can avoid damage to the screen printing screen. In addition, copper powder is used as a conductive paste, which can be cured at a lower preset temperature and in a shorter preset time, which can avoid the crystallization of the amorphous silicon structure and further influence on the heterojunction battery. At the same time, during the curing process, the conductive paste can be partially embedded in the first transparent conductive layer 14 and form an alloy with the first transparent conductive layer 14, thereby forming a good contact with the first transparent conductive layer 14.
[0054] In other embodiments, the substrate may be pre-textured, polished, and the like, and a corresponding battery structure may be prepared on a second side surface S2 of the substrate opposite to the first side surface S1. For details, please refer to the description of the following embodiments.
[0055] See also Figure 4 As shown, Figure 4 : is a schematic flow chart of a heterojunction battery preparation method provided by another embodiment of the present application, which may include:
[0056] Step S41: texturing the first side surface and the second side surface of the substrate;
[0057] Step S42: performing a planarization process on at least a portion of the first side surface after texturing;
[0058] Step S43: sequentially preparing a first intrinsic passivation layer, a first doping layer and a first transparent conductive layer on a first side surface of the substrate;
[0059] Step S44: using spherical copper powder as conductive paste, and printing the conductive paste on the surface of the first transparent conductive layer away from the substrate by screen printing;
[0060] Step S45: curing the conductive paste printed on the first transparent conductive layer for a preset time at a preset temperature to obtain a first metal electrode, wherein an alloy is formed at a contact interface between the first metal electrode and the first transparent conductive layer;
[0061] Step S46: sequentially preparing a second intrinsic passivation layer, a second doping layer, a second transparent conductive layer and a second metal electrode on the second side surface of the substrate.
[0062] In some embodiments, the substrate 21 may be made of silicon.
[0063] In some embodiments, step S41 may specifically be to use an alkaline texturing solution to texturize the first side surface S1' and the second side surface S2' of the substrate 21, and by controlling the reaction time, solution concentration, temperature and other parameters of the texturing process, the first side surface S1' and the second side surface S2' of the substrate 21 are respectively formed with pyramid-shaped fine structures, such as Figure 5 By texturing the substrate 21, the absorption of sunlight can be maximized to improve the conversion efficiency of the solar cell.
[0064] In some embodiments, the alkaline texturing solution may include any one of KOH, NaOH, and TMAH (tetramethylammonium hydroxide).
[0065] In the embodiment of the present application, the first side surface S1 ′ and the second side surface S2 ′ are disposed opposite to each other. The first side surface S1 ′ may be a backlight surface of the substrate 21 , and the second side surface S2 ′ may be a light-facing surface of the substrate 21 .
[0066] In some other embodiments, the substrate 21 may be cleaned before step S41 to remove stains and impurities on the surface of the substrate 21 .
[0067] In some embodiments, step S42 may be specifically to polish the first side surface S1' after texturing with an alkaline solution to remove the pyramid tip structure of at least a portion of the first side surface S1' and retain the pyramid base structure, see Figure 6 As shown, a planar microstructure is formed in at least a partial area of the first side surface S1 ′.
[0068] It should be noted that Figure 6 The surface morphology of the substrate 21 after the texturing and planarization treatment is shown in FIG. 1 , wherein the surface morphology is appropriately enlarged to facilitate the clear display of the fine structural features, and the actual size may vary depending on the manufacturing process and specific conditions. In other embodiments, the entire area of the first side surface S1' may be set to be a plane, such as Figure 2 shown.
[0069] By forming a planar microstructure on the first side surface S1 ′, the reflectivity of the battery is further improved, thereby improving the photoelectric conversion efficiency.
[0070] In some embodiments, after step S41 and before step S42, a mask layer may be formed on the second side surface S2' of the substrate 21. The mask layer material may be silicon oxide, and the formation method may include green light or red light laser oxidation method, or chain thermal oxidation method. In some embodiments, the thickness of the mask layer may be 5-50nm to protect the second side surface S2' of the substrate 21.
[0071] Accordingly, the method provided in this embodiment may further include: removing the mask layer before preparing the second intrinsic passivation layer 26. In some embodiments, the mask layer may be removed using a HF (hydrofluoric acid) solution.
[0072] Steps S43 to S45 can be implemented in the same manner as steps S11 to S13, and for the sake of brevity, they will not be described in detail here. The structure obtained after executing step S45 can be found in Figure 7As shown, the first intrinsic passivation layer 22, the first doping layer 23 and the first transparent conductive layer 24 sequentially conformally cover the first side surface S1' of the substrate 21, so that a planar microstructure also exists in some areas on the side surface of the first transparent conductive layer 24 away from the substrate 21. By using spherical copper powder as a conductive paste and curing it at a preset temperature for a preset time to prepare the first metal electrode 25, a good physical contact can be formed with the first transparent conductive layer 24, and damage to the screen and crystallization of the amorphous silicon structure can be avoided.
[0073] In some embodiments, step S46 may specifically include:
[0074] A second intrinsic passivation layer 26, a second doping layer 27 and a second transparent conductive layer 28 are sequentially formed on the second side surface S2' of the substrate 21 by using a coating process;
[0075] The second metal electrode 29 is prepared on the second transparent conductive layer 28 by using a screen printing process.
[0076] See also Figure 8 As shown, the second intrinsic passivation layer 26 , the second doping layer 27 and the second transparent conductive layer 28 may conformally cover the second side surface S2 ′ of the substrate 21 . Therefore, the side surface of the second transparent conductive layer 28 away from the substrate 21 may have a pyramid structure.
[0077] The coating process may include chemical vapor deposition or physical vapor deposition.
[0078] Among them, the second intrinsic passivation layer 26 can be amorphous, and in some embodiments, the second intrinsic passivation layer 26 can be intrinsic amorphous silicon. In some embodiments, the thickness of the second intrinsic passivation layer 26 can be 0.5 to 5 nm to effectively cover the defects on the surface of the substrate 21, improve the passivation effect, and do not affect the electron transmission effect. In some embodiments, the second intrinsic passivation layer 26 can be made of the same material as the first intrinsic passivation layer 22, and the thickness of the second intrinsic passivation layer 26 and the first intrinsic passivation layer 22 can be the same or different.
[0079] In the embodiment of the present application, the second doping layer 27 has a different doping type from the first doping layer 23. In some embodiments, the first doping layer 23 may be a P-type doping layer, which may be made of boron-doped amorphous silicon or boron-doped microcrystalline silicon, and the second doping layer 27 may be an N-type doping layer, which may be phosphorus-doped amorphous silicon or phosphorus-doped microcrystalline silicon. In some embodiments, the thickness of the second doping layer 27 may be 10 to 40 nm to prevent light from being absorbed by the doping layer and affecting the power generation effect of the solar cell. The thickness of the second doping layer 27 may be the same as or different from the thickness of the first doping layer 23.
[0080] In some embodiments, the second transparent conductive layer 28 may be made of indium tin oxide (ITO) or other transparent conductive oxides (TCO). In some embodiments, the second transparent conductive layer 28 may be made of at least one of indium oxide, tin oxide, and zinc oxide. In some embodiments, the thickness of the second transparent conductive layer 28 may be 70-120 nm to optimize the propagation path of light inside the battery and improve light absorption efficiency. In some embodiments, the second transparent conductive layer 28 may be arranged in the same manner as the first transparent conductive layer 24, such as using the same material and setting the same thickness, or may be arranged in different manners.
[0081] In some embodiments, the second metal electrode 29 may be prepared as follows:
[0082] Spherical copper powder is used as conductive paste, and the conductive paste is printed on the surface of the second transparent conductive layer 28 away from the substrate 21 by screen printing;
[0083] At a preset temperature, the conductive paste printed on the second transparent conductive layer 28 is cured for a preset time to obtain the second metal electrode 29 .
[0084] The diameter of the spherical copper powder may be 200 nm-1.2 μm, the preset temperature may be 250-300° C., and the preset duration may be 5-15 seconds. In some embodiments, the second metal electrode 29 may be prepared in the same manner as the first metal electrode 25 and achieve the same beneficial effects.
[0085] join Figure 8 As shown, the second metal electrode 29 may form an alloy at the interface in contact with the second transparent conductive layer 28 and may be partially embedded in the second transparent conductive layer 28 .
[0086] In some other embodiments, the method provided in the embodiment of the present application may further include: forming an anti-oxidation layer on the surface of at least one of the first metal electrode 25 and the second metal electrode 29 .
[0087] In some embodiments, the anti-oxidation layer may include at least one of silver, tin, and nickel.
[0088] Another aspect of the present application provides a heterojunction battery, see Figure 3 or Figure 7As shown, it may include a substrate (11, 21), a first intrinsic passivation layer (12, 22), a first doping layer (13, 23), a first transparent conductive layer (14, 24) and a first metal electrode (15, 25) sequentially prepared on a first side surface (S1, S1') of the substrate, wherein the first metal electrode (15, 25) is prepared using spherical copper powder as a conductive paste, and an alloy is formed at the contact interface between the first metal electrode (15, 25) and the first transparent conductive layer (14, 24).
[0089] In some embodiments, see Figure 8 As shown, the heterojunction battery may also include a second intrinsic passivation layer 26, a second doping layer 27, a second transparent conductive layer 28 and a second metal electrode 29 sequentially prepared on the second side surface S2' of the substrate, wherein the second metal electrode 29 may be prepared using spherical copper powder as a conductive paste, and the contact interface between the second metal electrode 29 and the second transparent conductive layer 28 forms an alloy.
[0090] In another aspect of the present application, a photovoltaic module is provided, which may include the heterojunction cell of any one of the above embodiments.
[0091] So far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.
Claims
1. A method for preparing a heterojunction battery, characterized in that: include: Sequentially preparing a first intrinsic passivation layer, a first doping layer and a first transparent conductive layer on a first side surface of the substrate; Using spherical copper powder as conductive paste, printing the conductive paste on the surface of the first transparent conductive layer away from the substrate by screen printing; The conductive paste printed on the first transparent conductive layer is cured for a preset time at a preset temperature to obtain a first metal electrode, wherein an alloy is formed at a contact interface between the first metal electrode and the first transparent conductive layer.
2. The method according to claim 1, characterized in that The preset temperature is 250-300° C., and the preset time is 5-15 seconds.
3. The method according to claim 2, characterized in that The method further comprises: A second intrinsic passivation layer, a second doping layer, a second transparent conductive layer and a second metal electrode are sequentially prepared on the second side surface of the substrate.
4. The method according to claim 3, characterized in that The second metal electrode is prepared, comprising: Using spherical copper powder as conductive paste, printing the conductive paste on the surface of the second transparent conductive layer away from the substrate by screen printing; At the preset temperature, the conductive paste printed on the second transparent conductive layer is cured for the preset time to obtain a second metal electrode.
5. The method according to claim 1, characterized in that: The first metal electrode is partially embedded in the first transparent conductive layer.
6. The method according to any one of claims 1 to 5, characterized in that Before sequentially preparing the first intrinsic passivation layer, the first doping layer and the first transparent conductive layer on the first side surface of the substrate, the method further comprises: Texturing the first side surface and the second side surface of the substrate; At least a portion of the first side surface after texturing is planarized.
7. The method according to any one of claims 1 to 5, characterized in that After obtaining the first metal electrode, the method further includes: forming an anti-oxidation layer on the surface of the first metal electrode.
8. The method according to claim 7, characterized in that The anti-oxidation layer includes at least one of silver, tin, and nickel.
9. The method according to any one of claims 1 to 5, characterized in that The diameter of the spherical copper powder is smaller than the width of the first metal electrode.
10. A heterojunction battery, characterized in that: It includes a substrate, a first intrinsic passivation layer, a first doping layer, a first transparent conductive layer and a first metal electrode sequentially prepared on the first side surface of the substrate, wherein the first metal electrode is prepared using spherical copper powder as a conductive paste, and an alloy is formed at the contact interface between the first metal electrode and the first transparent conductive layer.
11. A photovoltaic module, characterized in that: Including the heterojunction battery as described in claim 10.