Solar cell, preparation method thereof and photovoltaic module

Abstract

The invention provides a solar cell, a preparation method thereof and a photovoltaic module, and relates to the field of photovoltaic technology. The solar cell comprises a cell substrate, a dielectric layer, a first conductive layer and a second conductive layer, the dielectric layer is arranged on the surface of the cell substrate, and a groove exposing the surface of the cell substrate is formed in the dielectric layer. At least part of the first conductive layer is arranged in the groove and is in electric contact with the surface of the battery substrate, and the material of the first conductive layer comprises graphene. The second conductive layer is arranged on the side, away from the cell substrate, of the first conductive layer and is in electric contact with the first conductive layer. The first conducting layer and the second conducting layer are connected to serve as a grid line, resistance of the grid line is reduced, loss is reduced in the energy conversion process, the first conducting layer is made of graphene, and compared with an existing silver grid line, the preparation cost of the grid line is low.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a solar cell and a method for preparing the same. Background Art

[0002] In the field of solar cell technology, the electrode preparation of solar cells affects the cost and conversion efficiency of the cells. Among the current electrode preparation processes, the screen printing process is the most widely used. However, the cost of screen printing is more dependent on the price of the slurry. As the price of the slurry rises, the cost of screen printing also rises. Copper electroplating can use base metals instead of precious metals, greatly reducing the cost of process materials, but its cost is mainly restricted by graphics and electroplating equipment, and it is not possible to put it into large-scale mass production at present.

[0003] Based on this, how to reduce energy loss, improve energy conversion efficiency and reduce battery production costs is an urgent problem to be solved in this field. Summary of the invention

[0004] The present application proposes a solar cell and a preparation method thereof and a photovoltaic module, aiming to reduce energy loss, improve energy conversion efficiency, and reduce battery production costs.

[0005] In a first aspect, the present application provides a solar cell, which comprises a cell substrate, a dielectric layer, a first conductive layer, and a second conductive layer. The dielectric layer is disposed on the surface of the cell substrate, and a groove is disposed in the dielectric layer to expose the surface of the cell substrate. At least part of the first conductive layer is disposed in the groove and is in electrical contact with the surface of the cell substrate, and the material of the first conductive layer comprises graphene. The second conductive layer is disposed on a side of the first conductive layer away from the cell substrate, and is in electrical contact with the first conductive layer.

[0006] In some embodiments, the material of the second conductive layer includes graphite.

[0007] In some embodiments, the width of the second conductive layer is greater than the width of the first conductive layer, and along the width direction of the first conductive layer, two opposite boundaries of the second conductive layer exceed two opposite boundaries of the first conductive layer. Alternatively, the width of the second conductive layer is equal to the width of the first conductive layer, and along the width direction of the first conductive layer, two opposite boundaries of the second conductive layer overlap with two opposite boundaries of the first conductive layer.

[0008] In some embodiments, the battery substrate includes a first surface and a second surface opposite to each other, and the dielectric layer, the first conductive layer and the second conductive layer are disposed on the first surface; and / or the dielectric layer, the first conductive layer and the second conductive layer are disposed on the second surface.

[0009] In some embodiments, the dielectric layer, the first conductive layer and the second conductive layer are arranged on the first surface and the second surface, the width of the first conductive layer located on the first surface is smaller than the width of the first conductive layer located on the second surface, and the width of the second conductive layer located on the first surface is smaller than the width of the second conductive layer located on the second surface.

[0010] In some embodiments, the thickness of the first conductive layer ranges from 100 nm to 120 nm, and the thickness of the second conductive layer ranges from 15 μm to 20 μm.

[0011] In the embodiment of the present application, the dielectric layer is disposed on the surface of the battery substrate, and the dielectric layer is provided with a groove exposing the surface of the battery substrate, at least a portion of the first conductive layer is disposed in the groove, and is in electrical contact with the surface of the battery substrate, and the second conductive layer is disposed on a side of the first conductive layer away from the battery substrate, and is in electrical contact with the first conductive layer. The first conductive layer and the second conductive layer are connected as a grid line, which is conducive to reducing the resistance of the grid line, thereby reducing the loss in the energy conversion process and improving the energy conversion efficiency, and a portion of the grid line (the first conductive layer) is made of graphene, and compared with the current silver grid line, the preparation cost of the grid line is lower.

[0012] In a second aspect, the present application also provides a method for preparing a solar cell, the method comprising: forming a dielectric layer on the surface of a battery substrate, wherein a groove exposing the surface of the battery substrate is provided in the dielectric layer; forming a first conductive layer, wherein at least a portion of the first conductive layer is located in the groove and is electrically in contact with the surface of the battery substrate, and the material of the first conductive layer comprises graphene; forming a second conductive layer, wherein the second conductive layer is arranged on a side of the first conductive layer away from the battery substrate and is electrically in contact with the first conductive layer.

[0013] In some embodiments, the battery substrate includes a first surface and a second surface opposite to each other, and a dielectric layer is formed on the surface of the battery substrate, including forming a dielectric layer on the first surface and forming a dielectric layer on the second surface, wherein the width of the groove of the dielectric layer located on the first surface is smaller than the width of the groove of the dielectric layer located on the second surface.

[0014] In some embodiments, a first conductive layer is formed on the surface of the battery substrate through the grooves by electroplating deposition, and a second conductive layer is formed on the first conductive layer by electroplating deposition.

[0015] The above preparation method can be used to prepare the solar cell in the above-mentioned first aspect embodiment. The prepared solar cell has the above-mentioned beneficial effects, which will not be described in detail here.

[0016] In a third aspect, the present application further provides a photovoltaic assembly, comprising a plurality of solar cells in any one of the embodiments mentioned in the first aspect, wherein the plurality of solar cells are electrically connected.

[0017] The above photovoltaic components have the same beneficial technical effects as the solar cells improved in some of the above embodiments, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution in the present application, the following is a brief introduction to the drawings required for use in some embodiments of the present application. Obviously, the drawings described below are only drawings of some embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, not the actual size of the product involved in the embodiments of the present application, or the actual process of the method.

[0019] Figure 1 A schematic diagram of the structure of a solar cell provided in an embodiment of the present application;

[0020] Figure 2 Another schematic diagram of the structure of a solar cell provided in an embodiment of the present application;

[0021] Figure 3 A flow chart of a method for preparing a solar cell provided in an embodiment of the present application;

[0022] Figure 4 A diagram showing the steps for preparing a dielectric layer for a solar cell provided in an embodiment of the present application;

[0023] Figure 5 A diagram showing the steps of etching a dielectric layer of a solar cell provided in an embodiment of the present application;

[0024] Figure 6-7 A diagram showing the steps of preparing the first conductive layer of a solar cell provided in an embodiment of the present application;

[0025] Figure 8-Figure 9 A diagram showing the steps of preparing the second conductive layer of a solar cell provided in an embodiment of the present application;

[0026] Fig.10 A schematic diagram of the structure of a photovoltaic module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments provided by the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present application.

[0028] Unless the context requires otherwise, throughout the specification and claims, the term "comprising" is to be construed in an open, inclusive sense, ie, meaning "including, but not limited to."

[0029] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0030] When describing some embodiments, the term "connection" and its derivative expressions may be used. The term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For example, when describing some embodiments, the term "connection" may be used to indicate that two or more components are in direct physical or electrical contact with each other.

[0031] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0032] Exemplary embodiments are described herein with reference to cross-sectional views that are idealized exemplary drawings. In the drawings, the thickness of layers and the area of ​​regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are contemplated. Therefore, the exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but include deviations in shape due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0033] According to relevant technologies, the electrode preparation of solar cells affects the cost and conversion efficiency of the cells, and the optimization of the electrode preparation process is the focus of the industry. Currently, the electrodes of solar cells are mostly made using screen printing, but the silver paste required for printing makes screen printing costly. The copper electroplating metallization solution can use base metals instead of precious metals, but it is limited by graphics and electroplating equipment, and large-scale industrial production is not possible at present.

[0034] In order to solve the above problems, an embodiment of the present application provides a solar cell. Figure 1 A schematic diagram of the structure of a solar cell provided in an embodiment of the present application.

[0035] See also Figure 1 The solar cell 1 includes a cell substrate 10, a dielectric layer 20, a first conductive layer 301, and a second conductive layer 302, wherein the dielectric layer 20 is disposed on the surface of the cell substrate 10, and a groove 201 (the content indicated by the dashed box in the figure) is disposed in the dielectric layer 20 to expose the surface of the cell substrate 10. At least part of the first conductive layer 301 is disposed in the groove 201, and the first conductive layer 301 is in electrical contact with the surface of the cell substrate 10. The second conductive layer 302 is disposed on a side of the first conductive layer 301 away from the cell substrate 10, and the second conductive layer 302 is in electrical contact with the first conductive layer 301.

[0036] For example, Figure 1 As shown, at least part of the first conductive layer 301 is disposed in the groove 201, which may include three situations: in the Z direction, the upper surface of the first conductive layer 301 is lower than the edge of the groove 201, or the upper surface of the first conductive layer 301 is flush with the groove 201, in both cases, the entire first conductive layer 301 is located in the groove 201. Alternatively, in the Z-axis direction, the upper surface of the first conductive layer 301 is higher than the edge of the groove 201, part of the first conductive layer 301 is located in the groove 201, and part of the first conductive layer 301 protrudes out of the groove 201.

[0037] In the above embodiment, by setting the second conductive layer 302 on the side of the first conductive layer 301 away from the battery substrate 10, the first conductive layer 301 and the second conductive layer 302 are connected as a gate line 30, which is beneficial to reducing the resistance of the gate line 30. The photocurrent generated by the battery substrate 10 is collected through the gate line 30, which can reduce the loss caused by the current transmission on the gate line 30, thereby improving the energy conversion efficiency of the solar cell 1.

[0038] Furthermore, the first conductive layer 301 is made of graphene. Compared with the current silver grid lines, the material cost of the first conductive layer 301 is lower, which is beneficial to reducing the material cost of the grid lines 30 .

[0039] In some embodiments, see Figure 1 The material of the second conductive layer 302 includes graphite, which has good conductivity, so that the second conductive layer 302 has a smaller resistance, which is beneficial to reducing the resistance of the gate line 30. In addition, compared with the current silver gate line, the material cost of the second conductive layer 302 is lower, which is beneficial to reducing the material cost of the gate line 30.

[0040] In some embodiments, see Figure 1, the width of the second conductive layer 302 is greater than the width of the first conductive layer 301, and along the width direction of the first conductive layer 301, that is, in the X direction, two opposite boundaries of the second conductive layer 302 exceed two opposite boundaries of the first conductive layer 301. Alternatively, the width of the second conductive layer 302 is equal to the width of the first conductive layer 301, and along the width direction of the first conductive layer 301, that is, in the X direction, two opposite boundaries of the second conductive layer 302 coincide with two opposite boundaries of the first conductive layer 301.

[0041] That is, the orthographic projection of the second conductive layer 302 on the surface of the battery substrate 10 covers the orthographic projection of the first conductive layer 301 on the surface of the battery substrate 10. That is, the second conductive layer 302 covers the first conductive layer 301, and the second conductive layer 302 can protect the first conductive layer 301 and prevent the first conductive layer 301 from falling off.

[0042] Figure 2 Another schematic diagram of the structure of a solar cell provided in an embodiment of the present application.

[0043] In some embodiments, Figure 2 As shown, taking the cell substrate 10 as a tunnel oxide passivated contact cell substrate (TOPCON) as an example, the cell substrate 10 includes an emitter 1001 , a substrate 1002 , an ultra-thin tunnel oxide layer 1003 and a phosphorus-doped polysilicon layer 1004 which are stacked.

[0044] The emitter 1001 is located on the front side of the battery substrate 10. In the silicon-based battery substrate, the emitter 1001 is usually a P-doped P-type emitter. The substrate 1002 is the main part of the battery substrate 10, which is usually a lightly doped N-type silicon substrate. It forms a PN junction with the emitter. The PN junction can generate photogenerated carriers when exposed to light. The ultra-thin tunneling oxide layer 1003 is thinner and its material includes silicon dioxide. Its function is to prevent electrons and holes from recombination without the action of an external electric field, while allowing carriers generated under light to pass through this oxide layer through the tunneling effect. The phosphorus-doped polysilicon layer 1004 is a polysilicon layer doped with phosphorus elements, which is usually used as the back surface field or back contact of the battery substrate 10. The ultra-thin tunneling oxide layer 1003 and the phosphorus-doped polysilicon layer 1004 constitute a passivation contact structure, allowing electrons to pass through while blocking holes and reducing the recombination of electrons and holes.

[0045] like Figure 2As shown, the battery substrate 10 includes a first surface 101 and a second surface 102 opposite to each other. The dielectric layer 20, the first conductive layer 301 and the second conductive layer 302 can be arranged on the first surface 101, the second surface 102, or both.

[0046] The first surface 101 is the front side of the battery substrate 10. When the battery substrate 10 is TOPCON, the dielectric layer 20 located on the first surface 101 includes a passivation film and an anti-reflection film. The material of the passivation film includes aluminum oxide, and the material of the anti-reflection film includes silicon nitride. The anti-reflection film is used to reduce the reflection loss of light and improve the light capture rate. The first conductive layer 301 and the second conductive layer 302 on the first surface 101 constitute the gate line on the front side.

[0047] The second surface 102 is the back side of the battery substrate 10. The dielectric layer 20 located on the second surface 102 includes an anti-reflection film, and the material of the anti-reflection film includes silicon nitride. The first conductive layer 301 and the second conductive layer 302 on the second surface 102 constitute the grid lines on the back side. The grid lines on the front side and the back side are used to collect the photocurrent generated by the battery substrate 10, and can be used for the electrical connection of multiple groups of batteries.

[0048] In some embodiments, see Figure 1 The dielectric layer 20, the first conductive layer 301, and the second conductive layer 302 are disposed on the first surface 101 and the second surface 102. The width of the first conductive layer 301 located on the first surface 101 in the groove 201 is smaller than the width of the first conductive layer 301 located on the second surface 102 in the groove 201, and the width of the second conductive layer 302 located on the first surface 101 is smaller than the width of the second conductive layer 302 located on the second surface 102.

[0049] The “width of the first conductive layer 301 ” refers to the size of the portion of the first conductive layer 301 located in the trench 201 along the X direction. The “width of the second conductive layer 302 ” refers to the size of the portion of the second conductive layer 302 covering the dielectric layer 20 and the first conductive layer 301 along the X direction.

[0050] In the above embodiment, the first surface 101 serves as the front side of the battery substrate 10. The width of the first conductive layer 301 and the second conductive layer 302 located on the front side is relatively small, and the light shielding area is relatively small. While providing good electrical contact and collecting current, the light shielding effect can be reduced, and the influence on photoelectric conversion can be reduced, thereby improving the energy conversion efficiency of the solar cell.

[0051] In some embodiments, taking a TOPCON cell with a length and width of 210 mm×182 mm as an example, along the Z direction, the depth of the groove 201 is 0.1 μm, and the thickness of the first conductive layer 301 ranges from 100 nm to 120 nm, for example, the thickness of the first conductive layer 301 is 100 nm, 105 nm, 110 nm, 115 nm or 120 nm. The thickness of the second conductive layer 302 ranges from 15 μm to 20 μm, for example, the thickness of the second conductive layer 302 is 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm.

[0052] In addition, the present application also provides a method for preparing a solar cell. Figure 3 A flow chart of a method for preparing a solar cell provided in an embodiment of the present application, Figures 4 to 8 The steps of preparing a solar cell provided in the embodiment of the present application are shown in FIG. The preparation method includes the following steps S110 to S130:

[0053] Step S110: See Figure 4-5 A dielectric layer 20 is formed on the surface of the battery substrate 10 , and a groove 201 exposing the surface of the battery substrate 10 is provided in the dielectric layer 20 .

[0054] In some embodiments, the battery substrate 10 includes a first surface 101 and a second surface 102 opposite to each other, and forming the dielectric layer 20 on the surface of the battery substrate 10 includes: forming the dielectric layer 20 on the first surface 101 , and forming the dielectric layer 20 on the second surface 102 .

[0055] like Figure 4 As shown, when the cell substrate 10 is a TOPCON cell, the dielectric layer 20 on the first surface 101 includes a passivation film and an anti-reflection film, wherein the material of the passivation film includes aluminum oxide, and the material of the anti-reflection film includes silicon nitride. The dielectric layer 20 on the second surface 102 includes an anti-reflection film, wherein the material of the anti-reflection film includes silicon nitride.

[0056] like Figure 5 As shown, by patterning the dielectric layer 20, a groove 201 exposing the surface of the battery substrate 10 is provided in the dielectric layer 20. That is, after the dielectric layer 20 is formed on the surface of the battery substrate 10, the anti-reflection film and the passivation film are etched on the first surface 101 of the battery substrate 10 according to the pre-designed electrode pattern using laser etching and wet etching technology, using ultraviolet picosecond laser to form a groove 201, and the groove 201 exposes the emitter 1001. In the same way, the anti-reflection film is etched on the second surface 102 according to the pre-designed electrode pattern to form a groove 201, and the groove 201 exposes the phosphorus-doped polysilicon layer 1004. The groove 201 area is the pre-designed electrode pattern area, which is used for subsequent electrode formation.

[0057] In some embodiments, Figure 5 As shown, the width of the groove 201 of the dielectric layer 20 located on the first surface 101 is smaller than the width of the groove 201 of the dielectric layer 20 located on the second surface 102. The "width of the groove 201" refers to the size of the groove 201 along the X direction.

[0058] For example, the etching width of the groove 201 on the first surface 101 is 10 μm, and the etching width of the groove 201 on the second surface 102 is 40 μm. The width of the groove 201 of the dielectric layer 20 on the first surface 101 is smaller than the width of the groove 201 of the dielectric layer 20 on the second surface 102, so that in the subsequent process, the size of the electrode (gate line 30) on the first surface 101 can be slightly smaller, reducing the light shielding effect, increasing the sunlight area of ​​the solar cell 1, and helping to improve the energy conversion efficiency.

[0059] Step S120: See Figure 6-7 , forming a first conductive layer 301, at least part of which is located in the groove 201 and is in electrical contact with the surface of the battery substrate 10, and the material of the first conductive layer includes graphene;

[0060] In some embodiments, the first conductive layer 301 is formed on the surface of the battery substrate 10 through the grooves 201 by electroplating deposition.

[0061] like Figure 6 As shown, after the etching in step S110 is completed, a via hole is partially formed on the dielectric layer 20 of the first surface 101 to expose the emitter 1001 for connecting the positive electrode of the electroplating power supply, and a via hole is partially formed on the dielectric layer 20 of the second surface 102 to expose the phosphorus-doped polysilicon layer 1004 for connecting the positive electrode of the electroplating power supply. After the connection is completed, the battery substrate 10 etched in step S110 is used as the positive electrode of the electroplating power supply and immersed in the dispersion of graphene oxide, and the negative electrode of the electroplating power supply uses a graphite electrode. Among them, the graphene oxide dispersion is prepared by adding graphene oxide powder to an aqueous solution of methanol (volume ratio: methanol / water=0.5), and ultrasonically vibrating for 2 hours to ensure that the graphene oxide is evenly dispersed in the solvent. At this time, the concentration of graphene oxide in the dispersion is about 2g / L.

[0062] Under a specific potential difference drive, for example, maintaining the positive and negative voltages at 0.5V, graphene oxide gathers and deposits toward the positive electrode of the power source. The positive electrode of the power source here refers to the emitter 1001 exposed by the groove 201 on the first surface 101, and the phosphorus-doped polysilicon layer exposed by the groove 201 on the second surface 102. The portion of the battery substrate 10 covered by the dielectric layer 20 will not have graphene oxide gathered and deposited. Figure 7As shown, the power-on time lasts for 30 seconds, and a 100-120 nm graphene oxide layer is deposited in the groove 201. After the deposition is completed, it is taken out and dried at a temperature of 100°C, and then immersed in a hydrazine hydrate solution with a concentration of 10g / L. The reducing solution is heated to 70°C. At this time, the graphene oxide layer at the electrode is reduced to a graphene layer. The graphene layer has excellent conductivity and good bonding with the battery substrate 10 at the electrode.

[0063] Step S130: See Figure 8-Figure 9 , forming a second conductive layer 302 , the second conductive layer 302 is arranged on a side of the first conductive layer 301 away from the battery substrate 10 , and is in electrical contact with the first conductive layer 301 .

[0064] In some embodiments, the second conductive layer 302 is formed on the first conductive layer 301 by electroplating deposition.

[0065] like Figure 8 As shown, after the drying and reduction process in step S120 is completed, the battery substrate 10 deposited with the first conductive layer 301 is used as the positive electrode of the electroplating power source and immersed in the graphite dispersion liquid, and the negative electrode of the electroplating power source adopts a graphite electrode. Among them, the graphite dispersion liquid is ultrafine graphite powder added to an organic dispersant, and the organic dispersant is an ethanol aqueous solution with the same concentration as the methanol aqueous solution in step S120, and the binder is ABS resin with a concentration of 100 mg / L.

[0066] Under the drive of a specific potential difference, for example, maintaining the positive and negative voltages at 2V, the graphite colloid gathers and deposits toward the positive electrode of the power source. The positive electrode of the power source here refers to the first conductive layer 301 in the groove 201 on the first surface 101, and the first conductive layer 301 in the groove 201 on the second surface 102. Fig. 9 As shown, a graphite layer of 15 μm to 20 μm is deposited on the first conductive layer 301 for 5 minutes. After the deposition is completed, the graphite layer is taken out and placed in an oxygen-free sintering furnace at 150°C for oxygen-free low-temperature curing for 30 minutes to remove moisture and most of the organic matter in the graphite layer, and to cure the ABS resin, thereby completing the preparation of the second conductive layer 302 on the first conductive layer 301.

[0067] The above preparation method can be used to prepare the solar cell in any of the aforementioned embodiments. Compared with the silver paste required for the current silver grid line and the equipment required for the related preparation process, the present solution adopts graphene oxide dispersion and graphite dispersion, which has lower cost, and the first conductive layer 301 and the second conductive layer 302 are connected in parallel as a grid line 30, so that the resistance of the grid line 30 is small, and the energy loss when the current is transmitted on the grid line 30 is small, which is beneficial to improving the energy conversion efficiency of the solar cell.

[0068] In addition, the present application also provides a photovoltaic module, such as Fig.10As shown, Fig.10 A schematic diagram of the structure of a photovoltaic assembly provided in the present application. The photovoltaic assembly 2 includes a plurality of solar cells 1 in any of the embodiments mentioned in the first aspect, and the plurality of solar cells 1 are electrically connected. The photovoltaic assembly 2 can adjust the number of solar cells 1 in the assembly according to demand to convert solar energy into a certain scale of electrical energy.

[0069] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that a person skilled in the art can think of within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A solar cell, characterized in that: include: Battery substrate; A dielectric layer is disposed on the surface of the battery substrate, wherein the dielectric layer is provided with a groove exposing the surface of the battery substrate; a first conductive layer, at least partially disposed in the groove and in electrical contact with a surface of the battery substrate; The material of the first conductive layer includes graphene; The second conductive layer is disposed on a side of the first conductive layer away from the battery substrate and is in electrical contact with the first conductive layer.

2. The solar cell according to claim 1, characterized in that The material of the second conductive layer includes graphite.

3. The solar cell according to claim 1, characterized in that The width of the second conductive layer is greater than that of the first conductive layer, and along the width direction of the first conductive layer, two opposite boundaries of the second conductive layer exceed two opposite boundaries of the first conductive layer; or The width of the second conductive layer is equal to the width of the first conductive layer. Along the width direction of the first conductive layer, two opposite boundaries of the second conductive layer coincide with two opposite boundaries of the first conductive layer.

4. The solar cell according to claim 1, characterized in that The battery substrate includes a first surface and a second surface that are opposite; The dielectric layer, the first conductive layer and the second conductive layer are arranged on the first surface; and / or, The dielectric layer, the first conductive layer and the second conductive layer are arranged on the second surface.

5. The solar cell according to claim 4, characterized in that: The dielectric layer, the first conductive layer and the second conductive layer are arranged on the first surface and the second surface; The width of the first conductive layer located on the first surface is smaller than the width of the first conductive layer located on the second surface; The width of the second conductive layer located on the first surface is smaller than the width of the second conductive layer located on the second surface.

6. The solar cell according to any one of claims 1 to 5, characterized in that The thickness of the first conductive layer ranges from 100 nm to 120 nm; The thickness of the second conductive layer is in the range of 15 μm to 20 μm.

7. A method for preparing a solar cell, characterized in that: include: forming a dielectric layer on the surface of the battery substrate, wherein the dielectric layer is provided with a groove exposing the surface of the battery substrate; forming a first conductive layer, wherein at least a portion of the first conductive layer is located in the groove and is in electrical contact with a surface of the battery substrate; the material of the first conductive layer includes graphene; A second conductive layer is formed. The second conductive layer is disposed on a side of the first conductive layer away from the battery substrate and is in electrical contact with the first conductive layer.

8. The preparation method according to claim 7, characterized in that: The battery substrate comprises a first surface and a second surface opposite to each other, and a dielectric layer is formed on the surface of the battery substrate, comprising: forming a dielectric layer on the first surface, and forming a dielectric layer on the second surface; Wherein, the width of the groove of the dielectric layer located on the first surface is smaller than the width of the groove of the dielectric layer located on the second surface.

9. The preparation method according to claim 7 or 8, characterized in that: Using electroplating deposition method, forming the first conductive layer on the surface of the battery substrate through the groove; The second conductive layer is formed on the first conductive layer by electroplating deposition.

10. A photovoltaic module, characterized in that: The invention comprises a plurality of solar cells according to any one of claims 1 to 6, wherein the plurality of solar cells are electrically connected.

Images