Stacked gate solar cell and photovoltaic module

Abstract

The invention provides a stacked gate solar cell and a photovoltaic module. The stacked gate solar cell comprises a silicon substrate. The first doped semiconductor layer is arranged on the first side of the silicon substrate. And the first current collection layer is arranged on one side, far away from the silicon substrate, of the first doped semiconductor layer. And the first transmission electrode is arranged on one side, far away from the silicon substrate, of the first current collection layer. Wherein a first cross section of the first transmission electrode along a first direction and a second direction is provided with a first reference edge and a first angle alpha opposite to the first reference edge, the first direction is an overlapping direction of the silicon substrate and the first doped semiconductor layer, and the second direction is perpendicular to the first direction and is perpendicular to an extending direction of the first transmission electrode; the first reference edge is parallel to the second direction. The surface of the first side of the silicon substrate is a first suede structure, a second cross section of the first suede structure along the first direction and the second direction has a second reference edge and a second angle beta adjacent to the second reference edge, the second reference edge is parallel to the second direction, and alpha is less than or equal to beta.

Description

Technical Field

[0001] The present disclosure relates to the technical field of solar cells, and in particular to a stacked solar cell and a photovoltaic module. Background Art

[0002] The stacked grid solar cell has a conductive seed layer on the surface of the cell to collect surface current, and an extremely fine conductive wire that transmits current is superimposed on the seed layer to form a stacked grid structure. The current collection path of this structure is from the cell surface to the conductive seed layer to the conductive wire, and the current moves vertically, which can reduce resistance.

[0003] Currently, when designing the cross-sectional shape of a conductive filament, the angles therein are generally a certain set of specific angles. This design cannot take into account the light trapping performance of solar cells under different surface conditions. Summary of the invention

[0004] In view of the above problems, embodiments of the present disclosure provide a stacked grid solar cell and a photovoltaic module.

[0005] One aspect of the present disclosure provides a stacked grid solar cell, comprising: a silicon substrate. A first doped semiconductor layer disposed on a first side of the silicon substrate. A first current collection layer disposed on a side of the first doped semiconductor layer away from the silicon substrate. And a first transmission electrode disposed on a side of the first current collection layer away from the silicon substrate. Wherein, a first cross section of the first transmission electrode along a first direction and a second direction has a first reference edge and a first angle α relative to the first reference edge, the first direction is the superposition direction of the silicon substrate and the first doped semiconductor layer, the second direction is perpendicular to the first direction, and the second direction is perpendicular to the extension direction of the first transmission electrode, and the first reference edge is parallel to the second direction. The surface of the first side of the silicon substrate is a first velvet structure, and a second cross section of the first velvet structure along the first direction and the second direction has a second reference edge and a second angle β adjacent to the second reference edge, the second reference edge is parallel to the second direction, and α≤β.

[0006] According to an embodiment of the present disclosure, the relationship between the first angle α and the second angle β satisfies: β / 4≤α≤β.

[0007] According to an embodiment of the present disclosure, the relationship between the first angle α and the second angle β satisfies: β / 3≤α≤β.

[0008] According to an embodiment of the present disclosure, the shapes of the first section and the second section are both triangles, and the second section also has a third angle γ relative to the second reference side. The relationship between the first angle α and the third angle γ satisfies: α≤K(90°-γ / 2), K is the correction coefficient, and 1≤K≤1.5.

[0009] According to an embodiment of the present disclosure, the first angle α is between 20° and 75°.

[0010] According to an embodiment of the present disclosure, a ratio of the first reference side to the maximum length of the second cross section along the first direction is in the range of 20-300.

[0011] According to an embodiment of the present disclosure, the stacked grid solar cell is a double-sided cell, and the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤70°.

[0012] According to an embodiment of the present disclosure, when the first side of the silicon substrate is the light-facing side, the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤25°. When the first side of the silicon substrate is the backlight side, the relationship between the third angle γ and the first angle α satisfies: 10°≤|α-γ|≤70°.

[0013] According to an embodiment of the present disclosure, the first side of the silicon substrate is a light-facing side, and the stacked grid solar cell further includes: a first passivation anti-reflection layer disposed on a side of the first doped semiconductor layer away from the silicon substrate. A first interface passivation layer disposed on a second side of the silicon substrate, the second side of the silicon substrate being opposite to the first side of the silicon substrate. A second doped semiconductor layer disposed on a side of the first interface passivation layer away from the silicon substrate. A second passivation anti-reflection layer disposed on a side of the second doped semiconductor layer away from the silicon substrate. A second current collection layer disposed on a side of the second passivation anti-reflection layer away from the silicon substrate. And a second transmission electrode disposed on a side of the second current collection layer away from the silicon substrate. Wherein, the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤20°.

[0014] According to an embodiment of the present disclosure, the surface of the second side of the silicon substrate is a second velvet structure, and the third cross section of the second velvet structure along the first direction and the second direction has a third reference side and a fourth angle δ relative to the third reference side, and the third reference side is parallel to the second direction. The fourth cross section of the second transmission electrode along the first direction and the second direction has a fourth reference side and a fifth angle ε relative to the fourth reference side, and the fourth reference side is parallel to the second direction. The relationship between the fourth angle δ and the fifth angle ε satisfies: 10°≤|δ-ε|≤70°.

[0015] According to an embodiment of the present disclosure, the stacked grid solar cell is a single-sided cell, and the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤70°.

[0016] According to an embodiment of the present disclosure, the first side of the silicon substrate is the backlight side, and the stacked grid solar cell further includes: a second interface passivation layer arranged on the first side of the silicon substrate. A third doped semiconductor layer arranged on the side of the second interface passivation layer away from the silicon substrate, the first doped semiconductor layer is arranged on the side of the second interface passivation layer away from the silicon substrate, and the doping types of the first doped semiconductor layer and the third doped semiconductor layer are opposite. A third passivation anti-reflection layer arranged on the side of the first doped semiconductor layer and the third doped semiconductor layer away from the silicon substrate. A third current collection layer arranged on the side of the third doped semiconductor layer away from the silicon substrate. A third transmission electrode arranged on the side of the third current collection layer away from the silicon substrate, the second cross section of the third transmission electrode along the first direction and the second direction has a sixth reference edge and a sixth angle ζ relative to the sixth reference edge, and the sixth reference edge is parallel to the second direction. And a fourth passivation anti-reflection layer arranged on the second side of the silicon substrate, the second side of the silicon substrate is opposite to the first side of the silicon substrate. Wherein, the relationship between the third angle γ and the first angle α satisfies: 10°≤|α-γ|≤70°, and / or the relationship between the sixth angle ζ and the third angle γ satisfies: 10°≤|ζ-γ|≤70°.

[0017] According to an embodiment of the present disclosure, the material of the first current collection layer and the first transmission electrode is any one or more combinations of metal, metal oxide, metal nitride, metal carbide, metal sulfide and graphene.

[0018] Another aspect of the present disclosure provides a photovoltaic module, comprising: a plurality of lattice solar cells according to any embodiment of the present disclosure, an encapsulation layer for covering surfaces of the plurality of lattice solar cells, and a cover plate for covering surfaces of the encapsulation layer away from the plurality of lattice solar cells.

[0019] According to an embodiment of the present disclosure, the first direction may be, for example, the incident direction of light. By controlling the cross-sectional top angle of the first transmission electrode to be less than or equal to the cross-sectional bottom angle of the first velvet structure on the surface of the battery, the light can be incident on the first velvet structure and trapped after being reflected once or multiple times by the first transmission electrode, thereby improving the utilization rate of sunlight by solar cells and achieving an improvement in the efficiency of solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0021] Figure 1 The stacking structure of a grid-stacking solar cell according to an embodiment of the present disclosure is schematically shown;

[0022] Figure 2 Schematically shows a cross-sectional view of a first transmission electrode along a first direction and a second direction according to an embodiment of the present disclosure;

[0023] Figure 3 A schematic diagram of a stacked structure of a solar cell combining a stacked grid and a TOPCon structure according to an embodiment of the present disclosure is shown;

[0024] Figure 4 The stacking structure of a back-contact stacked solar cell according to an embodiment of the present disclosure is schematically shown.

[0025] [Description of Reference Numerals]

[0026] 1-silicon substrate; 2-first doped semiconductor layer; 3-first current collection layer; 4-first transmission electrode; 5-first passivation anti-reflection layer; 6-first interface passivation layer; 7-second doped semiconductor layer; 8-second passivation anti-reflection layer; 9-second current collection layer; 10-second transmission electrode; 11-second interface passivation layer; 12-third passivation anti-reflection layer; 13-fourth passivation anti-reflection layer; 14-third doped semiconductor layer; 15-third current collection layer; 16-third transmission electrode. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0028] It should be noted that in the drawings or descriptions, similar or identical parts use the same figure numbers. The technical features in the various embodiments exemplified in the specification can be freely combined to form a new solution without conflict. In addition, each claim can be used as an embodiment alone or the technical features in each claim can be combined as a new embodiment. In the drawings, the shape or thickness of the embodiment can be expanded and simplified or conveniently indicated. Furthermore, the elements or implementations not shown or described in the drawings are in a form known to a person of ordinary skill in the art. In addition, although demonstrations of parameters containing specific values ​​may be provided herein, it should be understood that the parameters do not need to be exactly equal to the corresponding values, but can be approximated to the corresponding values ​​within an acceptable error tolerance or design constraint.

[0029] Unless there are technical obstacles or contradictions, the above-mentioned various embodiments of the present disclosure can be freely combined to form additional embodiments, and these additional embodiments are all within the protection scope of the present disclosure.

[0030] Although the present disclosure is described in conjunction with the accompanying drawings, the embodiments disclosed in the accompanying drawings are intended to exemplify the preferred embodiments of the present disclosure and should not be construed as limiting the present disclosure. The dimensional ratios in the accompanying drawings are merely illustrative and should not be construed as limiting the present disclosure.

[0031] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.

[0032] Figure 1 The stacking structure of a grid-stacking solar cell according to an embodiment of the present disclosure is schematically shown.

[0033] According to the embodiments of the present disclosure, Figure 1 As shown, the present disclosure provides a stacked grid solar cell, comprising: a silicon substrate 1. A first doped semiconductor layer 2 arranged on the first side of the silicon substrate 1. A first current collection layer 3 arranged on the side of the first doped semiconductor layer 2 away from the silicon substrate 1. And a first transmission electrode 4 arranged on the side of the first current collection layer 3 away from the silicon substrate 1. Wherein, the first cross section of the first transmission electrode 4 along the first direction x and the second direction y has a first reference edge and a first angle α relative to the first reference edge, the first direction x is the superposition direction of the silicon substrate 1 and the first doped semiconductor layer 2, the second direction y is perpendicular to the first direction x, and the second direction y is perpendicular to the extension direction of the first transmission electrode 4, and the first reference edge is parallel to the second direction y. The surface of the first side of the silicon substrate 1 is a first velvet structure, and the second cross section of the first velvet structure along the first direction x and the second direction y has a second reference edge and a second angle β adjacent to the second reference edge, the second reference edge is parallel to the second direction y, and α≤β.

[0034] In some embodiments, the silicon substrate of the lattice solar cell serves as a basic supporting structure of the solar cell, providing good mechanical stability and electrical performance.

[0035] For example, monocrystalline silicon or polycrystalline silicon can be used as the substrate. Depending on the application scenario and design requirements of the solar cell, the size of the silicon substrate can vary, but is usually within a certain standard range. The silicon substrate can be a P-type doped, N-type doped, or a silicon wafer with a conductivity type close to that of the intrinsic conductivity.

[0036] The surface of the first side of the silicon substrate is processed into a first velvet structure (for example, a pyramid structure), which can increase the capture and reflection of light, thereby improving the photoelectric conversion efficiency of the solar cell. The cross section of the first velvet structure along the first direction (i.e., the superposition direction of the silicon substrate and the first doped semiconductor layer) has a second angle β, and this angle design helps to optimize the scattering and capture of light.

[0037] The first doped semiconductor layer is disposed on the first side of the silicon substrate (e.g., the upper surface facing the sun) and is formed by a specific doping process to achieve electrical contact between the silicon substrate and the first current collection layer. This layer can be N-type or P-type doped, depending on the overall design of the solar cell.

[0038] For example, the first doped semiconductor layer may be composed of one or more of single crystal silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon.

[0039] For another example, the first doped semiconductor layer is a P-type or N-type doped polysilicon poly layer with a thickness between 100nm and 400nm or 80nm and 300nm. The P-type is generally doped with group III elements. The N-type is generally doped with group V elements or group VI elements.

[0040] It can be understood that the first side of the silicon substrate can be the light-facing side or the backlight side, which can be determined based on the type of solar cell and the requirements of the usage scenario.

[0041] The first current collection layer is located on the side of the first doped semiconductor layer away from the silicon substrate, and is used to effectively collect and transmit the current generated by photoelectric conversion. This layer usually has good conductivity and good contact with the first doped semiconductor layer.

[0042] For example, the first current collection layer is usually made of materials such as metal or metal oxide, which have good conductivity and good contact with the doped semiconductor layer. The current collection layer can be designed in a grid, interdigitated, dot or other shape to optimize the current collection and transmission efficiency.

[0043] The first transmission electrode is arranged on a side of the first current collection layer away from the silicon substrate, serving as an interface connected to an external circuit and used for conducting the collected current out of the solar cell.

[0044] For example, the first transmission electrode can be made of metal or metal alloy, which has good conductivity and good contact with the current collection layer. The shape and size of the transmission electrode are usually determined according to the overall design of the solar cell and the current collection requirements.

[0045] The cross section of the first transmission electrode along the first direction also has a first angle α, and α≤β. The second angle β is designed to be greater than or equal to the vertex angle (first angle α) of the first transmission electrode. This design ensures that when light is incident from the surface of the solar cell, they can be effectively reflected and scattered, thereby increasing the light capture and conversion efficiency.

[0046] Preferably, the relationship between the first angle α and the second angle β satisfies: β / 4≤α≤β. The second angle β may be 45° to 75°, preferably 48° to 60°.

[0047] Further preferably, the relationship between the first angle α and the second angle β satisfies: β / 3≤α≤β.

[0048] The disclosed embodiment provides a stacked solar cell with a specific structure, wherein the first side surface of the silicon substrate is processed into a first velvet structure to optimize the capture and reflection of light. Through the design of the cross-sectional angle correlation between the first transmission electrode and the first velvet structure, the left and right sides of the first transmission electrode can reflect light, and after one or more reflections, the light is reflected back to the first velvet structure on the surface of the cell, and then absorbed by the surface of the cell, increasing the amount of light received by the cell, thereby increasing the output power of the solar cell.

[0049] Figure 2 The cross-sectional view of the first transmission electrode along the first direction and the second direction according to the embodiment of the present disclosure is schematically shown.

[0050] According to the embodiments of the present disclosure, Figure 2 As shown, the shapes of the first section and the second section are both triangles, and the second section also has a third angle γ relative to the second reference side. The relationship between the first angle α and the third angle γ satisfies: α≤K(90°-γ / 2), K is the correction coefficient, and 1≤K≤1.5.

[0051] In some embodiments, the first transmission electrode of the stacked solar cell is further described in detail: The cross section of the first transmission electrode along the first direction is designed to be a triangle, which means that the electrode has a vertex and a relatively wide bottom in a direction perpendicular to the surface of the silicon substrate.

[0052] For example, the triangle of the cross-section of the first transmission electrode may be a regular triangle such as an equilateral triangle, an isosceles triangle or an oblique triangle. However, based on different processing techniques, it may also be a quasi-triangle, that is, the side or bottom of the triangular cross-section may include one or more bends or arcs. The second reference side is the bottom of the triangle corresponding to the second cross-section.

[0053] The apex angle (ie, the angle at the vertex) of the triangle is specially designed to match the characteristic angle of the first pile structure.

[0054] The first texture structure has not only a specific second angle in a second direction perpendicular to the first direction but also a third angle in the first direction. Here, the second direction is defined as a direction perpendicular to the extending direction of the first transfer electrode.

[0055] It should be noted that the extension direction of the first transmission electrode is parallel to the surface of the solar cell, and according to different electrode pattern designs, the first transmission electrode in its entirety or in part can extend in any direction parallel to the surface of the solar cell. The embodiment of the present disclosure does not limit the extension direction of the first transmission electrode.

[0056] For example, the cross-sectional shape of the first velvet structure is an isosceles triangle. Since the vertex angle of the triangle is designed to be less than or equal to the base angle of the velvet cross section (i.e., the angle of the velvet structure at the widest point in the second direction, but considering the complexity of the velvet structure, it is simplified to the concept of the base angle for explanation), this design can obtain the relationship between the first angle α and the third angle γ to satisfy: α≤K (90°-γ / 2), K is the correction coefficient, and 1≤K≤1.5, so that the light can be reflected back to the velvet structure at a more favorable angle when it reaches the first transmission electrode. Through this design, the light forms a path of multiple reflections and scattering between the first transmission electrode and the velvet structure, thereby increasing the residence time and absorption efficiency of the light inside the solar cell.

[0057] The stacked grid solar cell of the disclosed embodiment further optimizes the current collection and transmission path by controlling the angular relationship between the top angle of the first transmission electrode and the top angle of the velvet structure on the surface of the silicon substrate, thereby improving the light capture efficiency of the solar cell and thus improving the overall photoelectric conversion efficiency.

[0058] According to an embodiment of the present disclosure, the first angle α is between 20° and 75°.

[0059] Research has found that if the first angle α is too small, while ensuring the same effective transmission area, the height of the conductive wire (first transmission electrode) will inevitably be higher, and it will be easy to deflect and flip during the welding process. In addition, if the first angle α is too small, the bottom edge of the conductive wire will also become narrower, which may easily cause loose welding and lead to desoldering.

[0060] In some embodiments, the specific range of the first angle of the first transmission electrode along the first direction section is further clarified, providing more specific parameter guidance for the design of the stacked solar cell.

[0061] For example, the cross-sectional shape along the first direction is still a triangle, and the vertex angle of the triangle is less than or equal to the bottom angle of the suede cross-section, so as to optimize the reflection and scattering effects of light.

[0062] Since the vertex angle of the triangle is less than or equal to the base angle of the velvet cross section, the maximum value of the first angle α can be 75°, that is, α≤75°. At the same time, considering the actual preparation of the conductive wire, the minimum value of the first angle α is set to 20°, and the range of the first angle α can be 20°≤α≤75°. Therefore, it can be ensured that the reflection and scattering path of the light between the first transmission electrode and the first velvet structure is more optimized, so as to further enhance the light trapping effect of the first velvet structure, so that more light can be captured and converted into electrical energy.

[0063] The first angle (i.e., the angle of the triangular cross section along the first direction) is clearly limited to a range of 20° to 75°. This range is selected based on a comprehensive consideration of light reflection, scattering, and current transmission efficiency, aiming to achieve the best photoelectric conversion efficiency.

[0064] The stacked solar cell of this embodiment provides more specific parameter guidance for the design of the stacked solar cell by clarifying the specific range (20°~75°) of the first angle of the cross section of the first transmission electrode along the first direction. The selection of this range is intended to achieve the best photoelectric conversion efficiency, while optimizing the reflection and scattering of light and the transmission path of current.

[0065] According to an embodiment of the present disclosure, a ratio of the first reference side to the maximum length of the second cross section along the first direction x is in the range of 20-300.

[0066] In some embodiments, a key parameter, namely, a length ratio of the first transmission electrode to the first velvet structure in a specific direction, is introduced to provide more detailed guidance for the design of stacked solar cells.

[0067] For example, the cross-sectional shape of the first transmission electrode along the first direction is a triangle, and the vertex angle of the triangle is less than or equal to the bottom angle of the velvet cross-section to optimize the reflection and scattering effect of light. The first angle (i.e., the angle of the triangular cross-section along the first direction) can be appropriately adjusted according to actual needs.

[0068] In order to balance the shading effect and the current transmission performance, the width of the base (first reference side) of the triangular cross section of the first transmission electrode is controlled to be, for example, 50 μm to 250 μm, preferably 80 μm to 150 μm. At the same time, in order to ensure the light trapping effect of the first velvet structure, combined with the above-mentioned angle relationship, for example, the maximum length of the cross section of the first velvet structure along the first direction is controlled to be 0.2 μm to 10 μm, preferably 0.5 μm to 4 μm.

[0069] Furthermore, the ratio between the maximum length of the cross section of the first transmission electrode along the first direction along the second direction (i.e., the length of the base of the triangle) and the maximum length of the cross section of the first velvet structure along the first direction along the first direction (i.e., the maximum height of the velvet structure in the first direction) can be limited to 5 to 1250, preferably 20 to 300. The selection of this ratio is intended to balance the light capture efficiency and the current transmission efficiency to achieve the best photoelectric conversion performance.

[0070] Since the length ratio is limited to the range of 20-300, it can be ensured that the first transmission electrode and the first velvet structure have good size matching, thereby further optimizing the light capture and reflection effects.

[0071] The tessellated solar cell of the embodiment of the present disclosure can further optimize the photoelectric conversion efficiency of the tessellated solar cell by limiting the length ratio of the first transmission electrode to the first velvet structure in a specific direction to a range of 20 to 300. The selection of this ratio takes into account both the reflection and scattering effect of light between the electrode and the velvet structure, and the transmission efficiency of current in the electrode.

[0072] According to an embodiment of the present disclosure, the stacked grid solar cell is a double-sided cell, and the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤70°.

[0073] In some embodiments, the stacked grid solar cell is designed as a bifacial cell, that is, both sides of the cell can receive light and generate current. According to whether the first side (i.e., the illuminated side) of the silicon substrate is the light-facing side or the backlight side, the absolute value of the angle difference between the third angle and the first angle is adjusted to optimize the photoelectric conversion efficiency.

[0074] In order to ensure that the first velvet structure captures light, it is calculated that the third angle γ can be 30°~90°, preferably 60°~84°. At the same time, combined with the range of the first angle α of 20°~75°, and α≤K(90°-γ / 2), it can be obtained that the absolute value of the angle difference between the third angle γ and the first angle α is 0°~70°. Preferably, the absolute value of the angle difference between the third angle γ and the first angle α is 0°~64°.

[0075] In this embodiment, the absolute value of the angle difference between the third angle and the first angle is between 0° and 70°. This design range ensures the coordination and balance of the performance of the first transmission electrode and the first velvet structure, helps to improve the overall structural stability and electrical performance of the solar cell, and reduces the optical and electrical losses that may be caused by the angle difference.

[0076] It should be noted that there is no specific size relationship between the third angle γ and the first angle α. The third angle γ may be equal to the first angle α, or the third angle γ may be larger or smaller than the first angle α.

[0077] When the angle difference is small (such as 10°), the reflection and scattering path of light between the first transmission electrode and the first velvet structure may be more direct and simple, which helps to reduce the loss of light and improve the light absorption efficiency.

[0078] When the angle difference is large (e.g., 60°), the light reflection and scattering path between the first transmission electrode and the second velvet structure may become more complicated, which may cause part of the light to be reflected multiple times between the electrode and the velvet structure, increasing the chance of light absorption.

[0079] By designing the angle difference range of 0°~70°, greater flexibility is provided, and the specific values ​​of the third angle and the first angle can be adjusted according to specific application scenarios and requirements.

[0080] The stacked solar cell of this embodiment designs a reasonable angle difference range between the third angle and the first angle, achieving a high photoelectric conversion efficiency and good current transmission performance. This structure not only improves the performance of the battery, but also increases its applicability and competitiveness in various application scenarios.

[0081] According to an embodiment of the present disclosure, when the first side of the silicon substrate 1 is the light-facing side, the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤25°. When the first side of the silicon substrate 1 is the backlight side, the relationship between the third angle γ and the first angle α satisfies: 10°≤|α-γ|≤70°.

[0082] For example, when the first side of the silicon substrate is the light-facing side, the transmission electrode can adopt a fine copper wire structure to ensure good current collection capability while reducing light blocking. In order to maximize the absorption and conversion efficiency of front light, the absolute value of the angle difference between the third angle and the first angle can be controlled within the range of 0° to 25°. This design helps to reduce the shading of the first transmission electrode and increase the reflection of light between the first transmission electrode and the first velvet structure, thereby improving the light capture efficiency and the short-circuit current density of the battery.

[0083] For another example, when the first side of the silicon substrate is the backlight side, the transmission electrode may use a wider copper wire or a different conductive material to provide sufficient current collection capacity on the backlight side. This side does not directly receive the main light source, but in order to utilize scattered light and reflected light, the absolute value of the angle difference between the third angle and the first angle is adjusted to be within the range of 10° to 70°. This larger angle difference design can increase the backlight side's ability to capture scattered light and improve the overall performance of the battery under different lighting conditions. At the same time, such a design also allows a more flexible electrode and velvet structure layout on the backlight side to adapt to different application scenarios and performance requirements.

[0084] The stacked grid solar cell of the disclosed embodiment can be optimized according to different lighting conditions as a bifacial cell by adjusting the angle difference between the cross-sectional vertex angle (first angle) of the first transmission electrode and the cross-sectional vertex angle (third angle) of the first velvet structure, thereby maintaining a high photoelectric conversion efficiency under different lighting environments.

[0085] Figure 3 The stacked structure of a solar cell combining a stacked grid and a TOPCon structure according to an embodiment of the present disclosure is schematically shown.

[0086] According to the embodiments of the present disclosure, Figure 3 As shown, the first side of the silicon substrate 1 is the light-facing side, and the stacked grid solar cell further includes: a first passivation anti-reflection layer 5 disposed on the side of the first doped semiconductor layer 2 away from the silicon substrate 1. A first interface passivation layer 6 disposed on the second side of the silicon substrate 1, and the second side of the silicon substrate 1 is opposite to the first side of the silicon substrate 1. A second doped semiconductor layer 7 disposed on the side of the first interface passivation layer 6 away from the silicon substrate 1. A second passivation anti-reflection layer 8 disposed on the side of the second doped semiconductor layer 7 away from the silicon substrate 1. A second current collection layer 9 disposed on the side of the second passivation anti-reflection layer 8 away from the silicon substrate 1. And a second transmission electrode 10 disposed on the side of the second current collection layer 9 away from the silicon substrate 1. Wherein, the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤20°.

[0087] In some embodiments, a stacked grid solar cell having a specific structure (TOPCon) is further described in detail.

[0088] The first passivation anti-reflection layer arranged on the side of the first doped semiconductor layer away from the silicon substrate can not only effectively reduce reflection and improve light utilization, but also passivate the semiconductor layer, reduce surface defects, and improve the stability and efficiency of the battery.

[0089] For example, the first passivation anti-reflection layer may be made of one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide and amorphous silicon.

[0090] The first interface passivation layer disposed on the back side (second side) of the silicon substrate mainly reduces surface defects on the back side of the silicon substrate and reduces recombination losses, thereby increasing the open circuit voltage and short circuit current of the battery.

[0091] For example, the first interface passivation layer may be composed of one layer or multiple layers, or may be composed of different materials in different regions. The material of the first interface passivation layer includes: one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide and amorphous silicon.

[0092] The second doped semiconductor layer is arranged on the side of the first interface passivation layer away from the silicon substrate. Its material can refer to the first doped semiconductor layer, but the doping type is opposite to that of the first doped semiconductor layer to form a complete PN junction or NP junction structure. This layer also participates in the photoelectric conversion process.

[0093] It is understandable that, based on different battery types or usage scenarios, the first interface passivation layer may not be provided, or an interface passivation layer may be provided only between or simultaneously between the first doped semiconductor layer and the silicon substrate.

[0094] The second passivation anti-reflection layer disposed on the side of the second doped semiconductor layer away from the silicon substrate is similar to the first passivation anti-reflection layer and is intended to reduce reflection, improve light utilization, and passivate the semiconductor layer.

[0095] The second current collection layer is arranged on a side of the second passivation anti-reflection layer away from the silicon substrate, and is used to effectively collect the current generated by the photoelectric conversion and transmit it to the transmission electrode.

[0096] The second transmission electrode is arranged on the side of the second current collection layer away from the silicon substrate, serving as the negative electrode (or positive electrode, depending on the doping type and connection method of the battery) of the battery, and is used to connect to an external circuit to realize current extraction.

[0097] The stacked solar cell in this embodiment also has a specific angle characteristic, that is, the absolute value of the angle difference between the third angle and the first angle on the light-facing side is in the range of 0° to 20°.

[0098] For TOPCon cells, since the shading rate needs to be considered on the front side, the first transmission electrode should be as sharp as possible. At the same time, considering the light trapping performance, the first velvet structure should also be set to be sharper, that is, the vertices have a smaller apex angle. Based on this, for TOPCon cells, the difference between the vertices of the first transmission electrode and the first velvet structure is small. This feature further reduces the light blocking by the first transmission electrode, while enhancing the secondary reflection of the light by the first transmission electrode, so that the secondary reflected light can be captured by the first velvet structure, increasing the short-circuit current, and thus improving the photoelectric conversion efficiency of the solar cell.

[0099] The stacked grid solar cell of this embodiment is a TOPCon (Tunnel Oxide Passivating Contacts) cell, which is characterized in that semiconductor layers with specific doping types and structures are arranged on both sides of the silicon substrate, and the photoelectric conversion efficiency and stability are optimized through structures such as passivation anti-reflection layer and current collection layer. In addition, the cell also has specific angle characteristics, which enables it to improve the light capture ability of the velvet structure. The design of this stacked grid solar cell structure not only improves the photoelectric conversion efficiency of the cell, but also enhances its stability and reliability.

[0100] According to the embodiments of the present disclosure, Figure 3As shown, the surface of the second side of the silicon substrate 1 is a second velvet structure, and the third cross section of the second velvet structure along the first direction x and the second direction y has a third reference side and a fourth angle δ relative to the third reference side, and the third reference side is parallel to the second direction y. The fourth cross section of the second transmission electrode along the first direction x and the second direction y has a fourth reference side and a fifth angle ε relative to the fourth reference side, and the fourth reference side is parallel to the second direction y. The relationship between the fourth angle δ and the fifth angle ε satisfies: 10°≤|δ-ε|≤70°.

[0101] In some embodiments, the suede structure on the second side (ie, the backlight side) of the silicon substrate and the cross-sectional angle of the second transmission electrode are further designed and optimized in detail. For example, the third reference side and the fourth reference side are both the base sides of the corresponding cross-sectional triangle.

[0102] The second side surface of the silicon substrate is designed as a second velvet structure to increase light capture efficiency and improve battery performance.

[0103] A cross section of the second velvet structure along the first direction has a fourth angle, which is optimized to ensure that light can be effectively absorbed by the battery.

[0104] The cross section of the second transmission electrode along the first direction has a fifth angle, and the angle difference between the fifth angle and the fourth angle is controlled within a range of 10° to 70°. Such a design allows a more flexible electrode layout to be adopted on the backlight side to adapt to different application scenarios and performance requirements.

[0105] On the light-facing side, based on the optimized design of the angle difference between the third angle and the first angle, the grid-type solar cell has achieved a high photoelectric conversion efficiency. On the backlight side, by optimizing the cross-sectional angles of the second velvet structure and the second transmission electrode, the light capture efficiency and current collection capacity are further improved, thereby improving the photoelectric conversion efficiency.

[0106] The stacked solar cell of this embodiment achieves further improvement in photoelectric conversion efficiency by precisely controlling the angle difference between the fourth angle and the fifth angle and combining the optimized design of the light-facing side and the backlight side. This design not only improves the performance of the cell, but also provides strong support for its wide application in practical applications.

[0107] According to an embodiment of the present disclosure, the stacked grid solar cell is a single-sided cell, and the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤70°.

[0108] In some embodiments, the stacked solar cell is designed as a single-sided cell, such as a back-contact cell, in which the side with the transmission electrode is the back side. The design combines the adjustment of the angle difference between the first angle (the top angle of the cross section of the transmission electrode) and the third angle (the top angle of the cross section of the velvet structure) to meet the efficiency improvement requirements of the single-sided cell.

[0109] A first transmission electrode is disposed on the first side (ie, the back side) for collecting and conducting current.

[0110] The absolute value of the angle difference between the cross-sectional vertex angle of the first transmission electrode (first angle) and the cross-sectional vertex angle of the first velvet structure (third angle) is controlled within the range of 0° to 70°. This design range allows for optimization of current collection and extraction while maintaining good light capture efficiency.

[0111] Below the first transmission electrode, the necessary passivation layer, doped semiconductor layer and current collection layer are arranged in sequence to ensure smooth current transmission and stable operation of the battery.

[0112] The second side (i.e. the side facing the light source) does not have a transmission electrode, but retains a suede structure. This design helps reduce light reflection and improve light capture efficiency.

[0113] To further improve the performance of the battery, other design features can be adopted, such as optimizing the doping concentration, improving the passivation layer material, etc. The overall structure of the battery is compact and stable, ensuring reliability and durability in practical applications.

[0114] The single-sided stacked grid solar cell of this embodiment achieves an improvement in the photoelectric conversion efficiency by optimizing the design of the transmission electrode and the velvet structure.

[0115] Figure 4 The stacking structure of a back-contact stacked solar cell according to an embodiment of the present disclosure is schematically shown.

[0116] According to the embodiments of the present disclosure, Figure 4As shown, the first side of the silicon substrate 1 is the backlight side, and the stacked grid solar cell further includes: a second interface passivation layer 11 disposed on the first side of the silicon substrate 1. A third doped semiconductor layer 14 disposed on the side of the second interface passivation layer 11 away from the silicon substrate 1, the first doped semiconductor layer 2 is disposed on the side of the second interface passivation layer 11 away from the silicon substrate 1, and the doping types of the first doped semiconductor layer 2 and the third doped semiconductor layer 14 are opposite. A third passivation anti-reflection layer 12 disposed on the side of the first doped semiconductor layer 2 and the third doped semiconductor layer 14 away from the silicon substrate 1. A third current collection layer 15 disposed on the side of the third doped semiconductor layer 14 away from the silicon substrate 1. A third transmission electrode 16 disposed on the side of the third current collection layer 15 away from the silicon substrate 1, the second cross section of the third transmission electrode 16 along the first direction x and the second direction y having a sixth reference side and a sixth angle ζ relative to the sixth reference side, and the sixth reference side is parallel to the second direction. And a fourth passivation anti-reflection layer 13 disposed on the second side of the silicon substrate 1, the second side of the silicon substrate 1 is opposite to the first side of the silicon substrate 1. The relationship between the third angle γ and the first angle α satisfies: 10°≤|α-γ|≤70°, and / or the relationship between the sixth angle ζ and the third angle γ satisfies: 10°≤|ζ-γ|≤70°.

[0117] In some embodiments, a structure of a back-contact stacked solar cell is further described, wherein a first side of the silicon substrate is a backlight side, and a second side is a light-facing side.

[0118] On the first side (backlight side) of the silicon substrate, a second interface passivation layer is provided, the main function of which is to reduce interface defects and improve the stability of the battery.

[0119] For example, the second interface passivation layer can be a tunneling oxide layer. The tunneling oxide layer is a very thin and dense oxide layer that can effectively reduce interface defects and improve the stability of the battery. At the same time, the tunneling oxide layer also has an excellent passivation effect, which can reduce the interface recombination current and improve the open circuit voltage and conversion efficiency of the battery.

[0120] For example, the tunnel oxide layer can be a very thin layer of silicon oxide (SiO x , such as SiO 2 ) and its thickness is, for example, between 1nm and 3nm.

[0121] The first doped semiconductor layer and the third doped semiconductor layer are arranged on the second interface passivation layer, and through appropriate doping processes, an N-type or P-type semiconductor region is formed for current collection and transmission. Different from the first doped semiconductor layer, the doping type of the third doped semiconductor layer is opposite to that of the first doped semiconductor layer, forming an alternating structure of N-type-P-type or P-type-N-type. This alternating structure helps to form a better built-in electric field and improve the separation efficiency of photogenerated carriers.

[0122] For example, the first doped semiconductor layer is a P-type doped polysilicon poly layer with a thickness between 100nm and 400nm and a width between 200μm and 700μm. The third doped semiconductor layer is an N-type doped polysilicon poly layer with a thickness between 80nm and 300nm and a width between 200μm and 700μm.

[0123] A third passivation anti-reflection layer is disposed on the side of the first doped semiconductor layer and the third doped semiconductor layer away from the silicon substrate. This layer not only has a passivation effect, but also can effectively reduce the reflection of light and improve the utilization rate of light.

[0124] For example, the material of the third passivation anti-reflection layer may refer to the material of the first passivation anti-reflection layer.

[0125] On the second side of the silicon substrate (light receiving side), a velvet structure is set to increase the light capture area and reduce reflection. At the same time, a fourth passivation anti-reflection layer is set on the velvet structure to further reduce light reflection and improve light absorption efficiency.

[0126] For example, the material of the fourth passivation anti-reflection layer may refer to that of the first passivation anti-reflection layer.

[0127] On the third passivation anti-reflection layer, a first current collection layer and a first transmission electrode, a third current collection layer and a third transmission electrode are arranged in sequence for collecting and deriving current. The sixth reference side is the base of the corresponding cross-sectional triangle. The absolute value of the angle difference between the cross-sectional vertex angle (first angle, sixth angle) of at least one of the two transmission electrodes and the cross-sectional vertex angle (third angle) of the velvet structure is controlled within the range of 10° to 70° to optimize light capture and current collection.

[0128] For back-contact solar cells, since the transmission electrode and the first velvet structure are both on the back, there is little need to consider the influence of the back shading rate. In order to enhance the current transmission performance, the transmission electrode of the back-contact solar cell can be relatively flat, and its vertex angle can be set larger. In order to reduce the back transmission loss of light, the first velvet structure on the back will be set sharper. Based on this, for back-contact solar cells, the difference between the vertex angle of the transmission electrode and the vertex angle of the first velvet structure will be relatively large.

[0129] By arranging the velvet structure and the fourth passivation anti-reflection layer on the second side, the light capture efficiency is effectively improved. Arranging the third passivation anti-reflection layer on the first side also further reduces the reflection of light and improves the utilization rate of light.

[0130] The stacked grid solar cell of this embodiment effectively improves the photoelectric conversion efficiency and current collection capacity of the cell by arranging the velvet structure and the fourth passivation anti-reflection layer on the second side and the third passivation anti-reflection layer on the first side. At the same time, by controlling the angle difference between the transmission electrode and the velvet structure, the photoelectric conversion efficiency of the cell is further improved.

[0131] According to an embodiment of the present disclosure, the material of the first current collection layer and the first transmission electrode is any one or more combinations of metal, metal oxide, metal nitride, metal carbide, metal sulfide and graphene.

[0132] In some embodiments, the materials of the first current collection layer and the first transmission electrode are optimized, and a combination of any one or more of metals (such as Ag, Cu, Al, Ni, Au, Zn, Sn, Pb, etc.), metal oxides (various TCOs, such as ITO, AZO, IWO, etc.), metal nitrides (TiN, etc.), metal carbides (TiC, etc.), metal sulfides and graphene are used.

[0133] Preferably, the transmission electrode is made of base metal, such as Al, Cu, etc., and other cheap metals based on aluminum and / or copper.

[0134] The first current collecting layer is disposed above the first doped semiconductor layer and is used for collecting current generated by the first doped semiconductor layer.

[0135] For example, the first current collection layer uses a combination of metal and metal oxide materials. Specifically, a thin layer of metal (such as silver, copper or nickel) can be used as a conductive core, and then a layer of metal oxide (such as aluminum oxide or titanium dioxide) is covered on it as a protective layer to improve the stability and durability of the current collection layer.

[0136] The first transmission electrode is disposed on the first current collection layer and is used for conducting the collected current out of the battery.

[0137] For example, the first transmission electrode uses a combination of metal carbide and graphene. Metal carbides (such as silicon carbide or tungsten carbide) have excellent conductivity and mechanical strength, while graphene has excellent electron mobility and flexibility. This combination of materials can significantly improve the conductivity and mechanical stability of the first transmission electrode.

[0138] Other parts of the battery (such as the second current collection layer, the second transmission electrode, etc.) can be configured with reference to the design of this embodiment.

[0139] The stacked solar cell of this embodiment improves the conductivity and mechanical stability of the cell by optimizing the material combination of the first current collection layer and the first transmission electrode, and further improves the photoelectric conversion efficiency of the cell by combining the angle correlation design of the second angle and the first angle. At the same time, the preparation cost of the cell electrode is also reduced.

[0140] For the stacked grid solar cell of the embodiment of the present disclosure, the present disclosure also provides a preparation method, for example, comprising:

[0141] Step a: The surface of the silicon substrate is textured to form a pyramid texture structure.

[0142] Step b: completing the surface passivation step. Before passivation, various types of doping layers can also be prepared, including various types of materials of the aforementioned types.

[0143] A passivation film and / or an anti-reflection film are formed on the front and back sides of the silicon substrate. The front passivation film and the anti-reflection film may be composed of one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, and amorphous silicon. The back passivation film may be composed of one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, and amorphous silicon.

[0144] The structure of the passivation layer can be a single layer or a multi-layer structure. For example, an aluminum oxide passivation layer is first prepared using the ALD (Atomic Layer Deposition) method, and then a single or multiple silicon nitride layers are formed thereon using PECVD.

[0145] The material of the passivation layer is as described above and will not be repeated here. The preparation method can be ALD, various CVD (such as PECVD (Plasma Enhanced Chemical Vapor Deposition), APCVD (Atmospheric Pressure Chemical Vapor Deposition), LPCVD (LowPressure Chemical Vapor Deposition), MOCVD (Metal-organic Chemical Vapor Deposition), etc.), various PVD (Physical Vapor Deposition, such as evaporation, sputtering), etc.

[0146] Step c: Perform a passivation film window opening process, such as using a laser or other process to remove the passivation layer.

[0147] Step d: forming a seed layer (current collection layer).

[0148] For example, the seed layer can be coated on the passivation film on the first surface with electrode slurry, and then sintered so that the electrode slurry passes through the passivation film and forms contact with the semiconductor film layer. However, it is preferred to form the seed layer by ALD, various CVD, PVD, chemical plating, electroplating, etc. after the aforementioned laser windowing. In the process of forming the seed layer, various steps such as patterning mask, annealing, sintering, plasticization, transfer, etc. can be performed.

[0149] Step e: forming a conductive wire (transmission electrode).

[0150] The conductive filaments may be formed after the electrode contact portion is completed. The conductive filaments may be made of, for example, Al or Cu.

[0151] Any details not included in the method example section are similar to those in the product example section. Please refer to the product example section and will not be repeated here.

[0152] An experimental verification was conducted on the stacked grid solar cell of the embodiment of the present disclosure, taking the TOPCon cell as an example.

[0153] Example: By controlling the silicon wafer texturing process and the conductive filament formation process, β≤γ is controlled. Comparative Example: By controlling the silicon wafer texturing process and the conductive filament formation process, β>γ is controlled. The experimental results are shown in Table 1 below.

[0154] Table 1 Optimization of angle relationships of stacked solar cells

[0155]

[0156] From the above data, it can be seen that the embodiment sets β≤γ, and the comparative example sets β>γ. The embodiment has corresponding improvements in current, fill factor and conversion efficiency relative to the comparative example. The reason is that β≤γ defined in the embodiment of the present disclosure can increase the light propagation path, ensure that the reflected light from the side of the conductive wire can be reflected onto the velvet surface once or multiple times, better trap light, be reused by the battery, increase the number of absorption times, and improve the utilization rate of light, thereby effectively improving the current and efficiency of the stacked solar cell.

[0157] Another aspect of the present disclosure provides a photovoltaic module, comprising: a plurality of lattice solar cells according to any embodiment of the present disclosure, an encapsulation layer for covering surfaces of the plurality of lattice solar cells, and a cover plate for covering surfaces of the encapsulation layer away from the plurality of lattice solar cells.

[0158] In some embodiments, as the core part of the photovoltaic module, the stacked grid solar cell is responsible for converting light energy into electrical energy. Its internal structure includes a silicon substrate, a tunneling oxide layer, a doped semiconductor layer, a current collection layer, a passivation anti-reflection layer, and a transmission electrode, which work together to achieve efficient photoelectric conversion.

[0159] Among them, there is a specific angle difference design between the cross-sectional angle of the first transmission electrode of the stacked solar cell along the first direction and the cross-sectional angle of the first velvet structure along the first direction, which enhances the velvet light trapping, further improves the photoelectric conversion efficiency of the stacked solar cell, and thus improves the output power of the photovoltaic module.

[0160] The encapsulation layer is located above the stacked solar cell and mainly plays a role of protection and support. It is made of materials with high light transmittance, high mechanical strength and high durability, such as EVA (ethylene-vinyl acetate copolymer) film or POE (polyolefin elastomer) film.

[0161] The encapsulation layer can effectively prevent external moisture, dust and other contaminants from entering the battery, thereby extending the battery life. At the same time, it can also provide a certain buffering effect to protect the battery from mechanical shock and vibration.

[0162] The cover plate is located above the encapsulation layer and is the outermost layer of the photovoltaic module. It is made of materials such as low-iron tempered glass or semi-tempered glass, and has the characteristics of high light transmittance, high mechanical strength and high weather resistance.

[0163] The main function of the cover is to protect the photovoltaic modules from damage by the external environment, such as wind, rain, ultraviolet radiation, etc. At the same time, it can also provide a certain heat insulation and sound insulation effect, and improve the overall performance of the photovoltaic modules.

[0164] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to a specific order or hierarchy.

[0165] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only reference directions of the drawings and are not intended to limit the scope of protection of the present disclosure. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or configurations will be omitted when they may cause confusion in the understanding of the present disclosure. In addition, the shapes, sizes, and positional relationships of the components in the drawings do not reflect the actual sizes, proportions, and actual positional relationships.

[0166] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the attached claims, the disclosure is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the attached claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the disclosure.

[0167] In addition, 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. With respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", as explained in terms of "including," used as a transitional word in the claims. Any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

[0168] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A stacked grid solar cell, characterized in that: include: Silicon substrate; A first doped semiconductor layer disposed on a first side of the silicon substrate; A first current collection layer disposed on a side of the first doped semiconductor layer away from the silicon substrate; as well as A first transmission electrode disposed on a side of the first current collection layer away from the silicon substrate; The first cross section of the first transmission electrode along the first direction and the second direction has a first reference side and a first angle α relative to the first reference side, the first direction is the superposition direction of the silicon substrate and the first doped semiconductor layer, the second direction is perpendicular to the first direction, and the second direction is perpendicular to the extension direction of the first transmission electrode, and the first reference side is parallel to the second direction; The surface of the first side of the silicon substrate is a first velvet structure, and the second cross section of the first velvet structure along the first direction and the second direction has a second reference edge and a second angle β adjacent to the second reference edge, the second reference edge is parallel to the second direction, and α≤β.

2. The stacked solar cell according to claim 1, characterized in that: The relationship between the first angle α and the second angle β satisfies: β / 4≤α≤β.

3. The stacked solar cell according to claim 2, characterized in that: The relationship between the first angle α and the second angle β satisfies: β / 3≤α≤β.

4. The stacked solar cell according to claim 1, characterized in that: The shapes of the first section and the second section are both triangles, and the second section also has a third angle γ relative to the second reference side. The relationship between the first angle α and the third angle γ satisfies: α≤K(90°-γ / 2), K is a correction coefficient, and 1≤K≤1.

5.

5. The stacked solar cell according to claim 4, characterized in that: The first angle α is between 20° and 75°.

6. The stacked solar cell according to claim 4, characterized in that: A ratio of the first reference side to the maximum length of the second cross section along the first direction is between 20 and 300.

7. The stacked solar cell according to claim 5, characterized in that: The stacked solar cell is a double-sided cell, and the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤70°.

8. The stacked solar cell according to claim 7, characterized in that: When the first side of the silicon substrate is the light-facing side, the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤25°; In the case where the first side of the silicon substrate is the backlight side, the relationship between the third angle γ and the first angle α satisfies: 10°≤|α-γ|≤70°.

9. The stacked solar cell according to claim 7, characterized in that: The first side of the silicon substrate is a light-facing side, and the stacked grid solar cell further comprises: A first passivation anti-reflection layer disposed on a side of the first doped semiconductor layer away from the silicon substrate; A first interface passivation layer disposed on a second side of the silicon substrate, wherein the second side of the silicon substrate is opposite to the first side of the silicon substrate; A second doped semiconductor layer disposed on a side of the first interface passivation layer away from the silicon substrate; A second passivation anti-reflection layer disposed on a side of the second doped semiconductor layer away from the silicon substrate; A second current collection layer disposed on a side of the second passivation anti-reflection layer away from the silicon substrate; and A second transmission electrode disposed on a side of the second current collection layer away from the silicon substrate; The relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤20°.

10. The stacked solar cell according to claim 9, characterized in that: The surface of the second side of the silicon substrate is a second velvet structure, and the third cross section of the second velvet structure along the first direction and the second direction has a third reference edge and a fourth angle δ relative to the third reference edge, and the third reference edge is parallel to the second direction; A fourth cross-section of the second transmission electrode along the first direction and the second direction has a fourth reference side and a fifth angle ε relative to the fourth reference side, the fourth reference side is parallel to the second direction, and a relationship between the fourth angle δ and the fifth angle ε satisfies: 10°≤|δ-ε|≤70°.

11. The stacked solar cell according to claim 5, characterized in that: The stacked solar cell is a single-sided cell, and the relationship between the third angle γ and the first angle α satisfies: 0°≤|α-γ|≤70°.

12. The stacked solar cell according to claim 11, characterized in that: The first side of the silicon substrate is a backlight side, and the stacked grid solar cell further comprises: A second interface passivation layer disposed on the first side of the silicon substrate; a third doped semiconductor layer disposed on a side of the second interface passivation layer away from the silicon substrate, the first doped semiconductor layer disposed on a side of the second interface passivation layer away from the silicon substrate, and the first doped semiconductor layer and the third doped semiconductor layer have opposite doping types; A third passivation anti-reflection layer is arranged on a side of the first doped semiconductor layer and the third doped semiconductor layer away from the silicon substrate; A third current collection layer is arranged on a side of the third doped semiconductor layer away from the silicon substrate; A third transmission electrode is disposed on a side of the third current collection layer away from the silicon substrate, wherein a second cross section of the third transmission electrode along the first direction and the second direction has a sixth reference side and a sixth angle ζ relative to the sixth reference side, and the sixth reference side is parallel to the second direction; and A fourth passivation anti-reflection layer is disposed on a second side of the silicon substrate, wherein the second side of the silicon substrate is opposite to the first side of the silicon substrate; The relationship between the third angle γ and the first angle α satisfies: 10°≤|α-γ|≤70°, and / or the relationship between the sixth angle ζ and the third angle γ satisfies: 10°≤|ζ-γ|≤70°.

13. The stacked solar cell according to claim 1, characterized in that: The material of the first current collection layer and the first transmission electrode is any one or more combinations of metal, metal oxide, metal nitride, metal carbide, metal sulfide and graphene.

14. A photovoltaic module, characterized in that: include: A plurality of stacked solar cells according to any one of claims 1 to 13; An encapsulation layer, used to cover the surface of a plurality of the stacked solar cells; A cover plate is used to cover the surface of the encapsulation layer away from the plurality of stacked solar cells.

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