Solar cell and photovoltaic module

Abstract

The utility model discloses a solar cell and a photovoltaic assembly. The solar cell comprises a first surface and a second surface which are opposite to each other, a grid line formed on the first surface and organic diffusion bands formed on two sides of the grid line, and the organic diffusion bands comprise organic matters in slurry for forming the grid line; one end, close to the first surface, of each grid line is a root part of the grid line, and the ratio of the width of the organic diffusion zone on any side of the grid line to the width of the root part of the grid line is 1-3. The widths of the organic diffusion bands on the two sides of the grid lines are within a reasonable range, so that the widths of the organic diffusion bands can be prevented from being too large, the shielding of the organic diffusion bands on the first surface is reduced, the light receiving area is increased, the photoelectric conversion efficiency is improved, the moderate widths of the organic diffusion bands are ensured, and organic matters in slurry are diffused to the two sides of the grid lines; the adhesive force between the grid lines and the first surface can be improved, and the grid lines are prevented from being separated from the first surface.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy, in particular to a solar cell and a photovoltaic component. Background Art

[0002] Solar cells are increasingly being used as a new energy alternative. Photovoltaic solar cells are devices that convert sunlight into electricity. Specifically, they use the principle of photovoltaics to generate charge carriers, which are then extracted using electrodes, facilitating efficient use of the electrical energy.

[0003] The grid lines of solar cells are typically formed by printing or laser-transferring a paste, followed by drying and curing. The paste may contain conductive particles such as silver, copper, and aluminum. However, after printing or laser-transferring the paste, during the transfer of the solar cell to the drying equipment and the drying and curing process, organic matter in the paste can diffuse onto the cell surfaces on both sides of the grid lines, forming wide organic diffusion bands on either side of the grid lines. These organic diffusion bands can reduce light transmittance and affect the cell's photoelectric conversion efficiency. Utility Model Content

[0004] The purpose of the utility model is to provide a solar cell and a photovoltaic module, which can reduce the shading area, improve the light transmittance, and improve the adhesion of the grid lines.

[0005] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0006] A solar cell comprises a first surface and a second surface opposite to each other, a grid line formed on the first surface and organic diffusion strips formed on both sides of the grid line, wherein the organic diffusion strips comprise organic matter in a paste used to form the grid line;

[0007] One end of the gate line close to the first surface is the root of the gate line, and the ratio of the width of the organic diffusion zone located on either side of the gate line to the width of the gate line root is 1-3.

[0008] In this way, the width of the organic diffusion bands on both sides of the gate line is within a reasonable range, which can prevent the width of the organic diffusion bands from being too large, thereby reducing the shading of the organic diffusion bands on the first surface, increasing the light-receiving area, and improving the photoelectric conversion efficiency. At the same time, the width of the organic diffusion bands is ensured to be moderate, and the organic matter in the slurry diffuses to both sides of the gate line, which can improve the adhesion between the gate line and the first surface and prevent the gate line from separating from the first surface.

[0009] In one implementation, the gate line includes a thin gate extending along a first direction;

[0010] The width of the root of the fine grid is 25μm-50μm. The width of the root of the fine grid is set within a reasonable range of 25μm-50μm to reduce the shading area of the fine grid while preventing the resistivity of the fine grid from being too high, thereby affecting the current collection and transmission efficiency; and / or, the width of the organic diffusion band located on either side of the fine grid is 30μm-100μm to prevent the organic diffusion bands on both sides of the fine grid from being too wide, thereby increasing the light-receiving area and improving the photoelectric conversion efficiency, while ensuring that the width of the organic diffusion band is moderate and improving the adhesion between the fine grid and the first surface.

[0011] In one implementation, the gate line includes a main gate extending along the second direction;

[0012] The width of the root of the main grid is 50μm-100μm. The width of the root of the main grid is set within a reasonable range of 50μm-100μm to reduce the shading area of the main grid while preventing the resistivity of the main grid from being too high, thereby affecting the current collection and transmission efficiency; and / or, the width of the organic diffusion band located on either side of the main grid is 100μm~250μm to prevent the organic diffusion bands on both sides of the main grid from being too wide, thereby increasing the light-receiving area and improving the photoelectric conversion efficiency, while ensuring that the width of the organic diffusion band is moderate and improving the adhesion between the main grid and the first surface.

[0013] In one implementation, the first surface has a textured structure, and the gate lines and organic diffusion strips are formed on the textured structure; and / or the first surface and / or the second surface have a textured structure and a transparent conductive layer formed on the textured structure, and the gate lines and organic diffusion strips are formed on the transparent conductive layer. The formation of the textured structure increases the surface area of the first surface, thereby increasing the contact area between the gate lines and the organic diffusion strips and the first surface, further improving the adhesion between the gate lines and the organic diffusion strips, while also reducing the contact resistance of the gate lines, thereby ensuring efficient current collection and transmission.

[0014] In one implementation, the texture structure includes a tower base structure, a pyramid structure and / or an inverted pyramid structure;

[0015] The height of the tower-shaped structure, pyramid structure, and / or inverted pyramid is less than or equal to 5 μm. By making the height of the tower-shaped structure, pyramid structure, and / or inverted pyramid less than or equal to 5 μm, the size of most conductive particles and the texture structure are comparable, which not only increases the contact area between the conductive particles and the texture structure, but also further improves the adhesion of the gate lines.

[0016] In one implementation, the textured structure is a pyramidal structure, with the organic material in the organic diffusion band located at the base of the pyramid. During the gate line formation process, rapid annealing is performed to maintain the organic material within a reasonable range, ensuring that the organic material remains only at the base of the pyramid and is absent from the upper portion of the pyramid. This reduces organic material residue and ensures better electrical interconnection.

[0017] In one implementation, the ratio of the gate line's height to its root width is 0.2 to 0.6. This arrangement minimizes the gate line's resistance while maintaining a sufficient cross-sectional area, thereby improving current collection and transmission. Furthermore, it reduces slurry usage and prevents waste.

[0018] In one implementation, the paste for forming the gate lines contains a plurality of organic substances, and the organic diffusion band includes any one of the plurality of organic substances in the paste.

[0019] In one implementation, the solar cell further includes a first semiconductor layer formed on a first surface, a second semiconductor layer formed on a second surface, and a gate line formed on the second surface. The first semiconductor layer and the second semiconductor layer have opposite conductivity types. The gate line formed on the first surface is electrically connected to the first semiconductor layer, and the gate line formed on the second surface is electrically connected to the second semiconductor layer. With this technical solution, the first semiconductor layer and the second semiconductor layer are located on the first surface and the second surface, respectively. The first semiconductor layer and the second semiconductor layer are separated by a large distance, which reduces the carrier recombination rate and helps improve the photoelectric conversion efficiency.

[0020] In one implementation, the solar cell further includes a first semiconductor layer and a second semiconductor layer formed on the first surface, wherein the first semiconductor layer and the second semiconductor layer have opposite conductivity types. A portion of the grid lines formed on the first surface are electrically connected to the first semiconductor layer, while another portion of the grid lines formed on the first surface are electrically connected to the second semiconductor layer. With this technical solution, both the first and second semiconductor layers are formed on the first surface, avoiding the problem of grid line shading, reducing light loss, and improving photoelectric utilization.

[0021] In one embodiment, the first semiconductor layer includes any one of doped amorphous silicon, doped microcrystalline silicon, and doped nanosilicon; and / or, the second semiconductor layer includes any one of doped amorphous silicon, doped microcrystalline silicon, and doped nanosilicon; and / or, the solar cell also includes a first interface passivation layer located at least between the first semiconductor layer and the substrate of the solar cell; and / or, the solar cell also includes a second interface passivation layer located at least between the second semiconductor layer and the substrate of the solar cell; and / or, the solar cell also includes a transparent conductive layer covering the first semiconductor layer and the second semiconductor layer on a side facing away from the substrate of the solar cell.

[0022] By adopting the above technical solution, the provision of the first interface passivation layer and the second interface passivation layer can achieve selective collection of carriers and reduce the carrier recombination rate in the corresponding areas of the substrate and the first semiconductor layer and the second semiconductor layer.

[0023] In one implementation, the substrate of a solar cell includes, on a first surface, a first region and a second region extending along a first direction and alternating in sequence along a second direction. The first region has a first texture structure, and the second region has a second texture structure, the first and second texture structures being different. A first grid line is disposed on the first texture structure, and the organic diffusion band of the first grid line does not extend to the boundary between the first and second regions. This prevents organic matter and conductive particles from the first grid line from diffusing into the first and second regions, which could cause the semiconductor layer in the first region to recombine with the semiconductor layer in the second region, thereby reducing the photoelectric conversion efficiency.

[0024] In one implementation, the distance between the edge of the organic diffusion strip of the first gate line and the boundary between the first region and the second region is 100 μm-200 μm, so as to ensure current transmission efficiency while preventing the semiconductor layer in the first region and the semiconductor layer in the second region from recombination.

[0025] A photovoltaic module comprises at least one solar cell as described above and an encapsulation layer, wherein the material of the encapsulation layer is different from the organic matter in the organic diffusion zone. This makes it easier to determine the edge of the organic diffusion zone and whether the organic matter in the organic diffusion zone comes from the grid line or the encapsulation layer.

[0026] Compared with the prior art, the beneficial effects of the photovoltaic module provided by the embodiment of the present invention are the same as the beneficial effects of the above-mentioned solar cell, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0028] Figure 1 A top-view SEM image of the gate line and the organic diffusion segment provided in an embodiment of the present utility model;

[0029] Figure 2 A longitudinal cross-sectional SEM image of a gate line provided in an embodiment of the present invention;

[0030] Figure 3 A cross-sectional view of a solar cell along the thickness direction of the substrate provided by an embodiment of the present utility model;

[0031] Figure 4A cross-sectional view of another solar cell along the substrate thickness direction provided by an embodiment of the present utility model;

[0032] Figure 5 This is a cross-sectional view of another solar cell provided by an embodiment of the present invention, taken along a plane parallel to the first surface.

[0033] Reference numerals:

[0034] 1-gate line, 2-organic diffusion belt, 3-transparent conductive layer, 4-first semiconductor layer, 5-first interface passivation layer, 6-substrate, 7-second semiconductor layer, 8-second interface passivation layer, 9-first region, 10-second region. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0038] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0039] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0040] See also Figure 1 The solar cell provided by an embodiment of the present invention includes a first surface and a second surface facing each other. The solar cell also includes a grid line 1 formed on the first surface and organic diffusion bands 2 formed on both sides of the grid line 1. The organic diffusion bands 2 include organic matter in the slurry used to form the grid line 1. That is, during the process of manufacturing the grid line 1, after the slurry is printed or laser transferred, and before the slurry is cured, one or more organic matters in the slurry diffuse toward the cell surfaces on both sides of the grid line 1, forming the organic diffusion bands 2 on both sides of the grid line 1.

[0041] Furthermore, the end of the gate line 1 close to the first surface is the root of the gate line 1, and the ratio of the width of the organic diffusion zone 2 located on either side of the gate line 1 to the width of the root of the gate line 1 is 1-3. Figure 1 As shown, the width of the root of the gate line 1 is D1, the width of the organic diffusion band 2 located on one side of the gate line 1 is D2, and the width of the organic diffusion band 2 located on the other side of the gate line 1 is D3. That is, D2:D1 and D3:D1 are both within the range of 1-3. In this way, the width of the organic diffusion band 2 on both sides of the gate line 1 is within a reasonable range, which can prevent the width of the organic diffusion band 2 from being too large, thereby reducing the shading of the organic diffusion band 2 on the first surface, increasing the light-receiving area, and improving the photoelectric conversion efficiency. At the same time, it ensures that the width of the organic diffusion band 2 is moderate, and the organic matter in the slurry diffuses to both sides of the gate line 1, which can improve the adhesion between the gate line 1 and the first surface and prevent the gate line 1 from detaching from the first surface. For example, the ratio of the width of the organic diffusion band 2 located on either side of the gate line 1 to the width of the root of the gate line 1 can be 1, 1.5, 1.8, 2, 2.5, 2.5, 2.8 or 3, etc.

[0042] Wherein, the edge of the organic diffusion band 2 away from the gate line 1 is the position where one or more organic substances in the slurry diffuse to the farthest point in the direction away from the gate line 1. After exceeding the edge of the organic diffusion band 2, the surface of the battery no longer contains organic substances diffused from the slurry. Along the extension direction of the gate line 1, the width of the organic diffusion band 2 at any position is the distance from the edge of one side of the gate line 1 at that position to the edge of the organic diffusion band 2 away from the gate line 1. In view of the fact that the widths of the organic diffusion band 2 and the gate line 1 at different positions may be different. Therefore, in this utility model, the width (D2 or D3) of the organic diffusion band 2 located on one side of the gate line 1 can refer to the average width of the organic diffusion band 2, or it can refer to the maximum width of the organic diffusion band 2. The width D1 at the root of the gate line 1 can refer to the average width at the root of the gate line 1, or it can refer to the maximum width at the root of the gate line 1. It can be understood that when the width of the organic diffusion zone 2 on one side refers to the average width of the organic diffusion zone 2, the width at the root of the gate line 1 refers to the average width at the root of the gate line 1; when the width of the organic diffusion zone 2 on one side refers to the maximum width of the organic diffusion zone 2, the width at the root of the gate line 1 refers to the maximum width at the root of the gate line 1. The maximum width of the organic diffusion zone 2 refers to the width at the widest position of the organic diffusion zone 2, and the maximum width at the root of the gate line 1 refers to the width at the widest position of the gate line 1.

[0043] In the present application, by optimizing the process steps and production lines, the time between the formation of the gate line 1 by silk screen printing or laser transfer and the sintering of the gate line 1 is reasonably set to reduce the spreading width of the organic matter on both sides of the gate line 1. Specifically, after the slurry printing or laser transfer, the time for transferring the solar cell to the drying equipment is controlled within 50 seconds, so that the spreading width of the organic matter on both sides of the gate line 1 is kept within a reasonable range, reducing the obstruction of the organic diffusion belt 2 on the first surface, increasing the light receiving area, and improving the photoelectric conversion efficiency. At the same time, the adhesion between the gate line 1 and the first surface is improved to prevent the gate line 1 from detaching from the first surface.

[0044] Specifically, the solar cell includes a substrate 6, a first semiconductor layer 4 and a second semiconductor layer 7, and the first semiconductor and the second semiconductor have opposite conductivity types. The two opposite sides of the substrate 6 are respectively a first surface and a second surface, the first surface corresponds to the backlight side of the solar cell, and the second surface corresponds to the light-facing side of the solar cell. In the case where the solar cell is a back-contact cell, the first semiconductor layer 4 and the second semiconductor layer 7 are both located on the first surface, and the grid lines 1 are only formed on the first surface, a portion of the grid lines 1 is electrically connected to the first semiconductor layer 4, and another portion of the grid lines 1 is electrically connected to the second semiconductor layer 7, thereby facilitating the grid lines 1 to extract electrons or holes and form current. In the case where the solar cell is a bifacial cell, the first semiconductor layer 4 and the second semiconductor layer 7 are respectively located on the first surface and the second surface, and a portion of the grid lines 1 is formed on the first surface and electrically connected to the first semiconductor layer 4, and another portion of the grid lines 1 is formed on the second surface and electrically connected to the second semiconductor layer 7.

[0045] In a specific embodiment, the gate line 1 includes a fine grid extending along the first direction, and the width of the root of the fine grid is 25μm-50μm. If the width of the root of the fine grid is too large, it will result in a larger shading area, affecting the photoelectric conversion efficiency of the solar cell. If the width of the root of the fine grid is too small, it will cause the contact resistance between the fine grid and the first semiconductor layer 4 or the second semiconductor layer 7 to be high, affecting the current transmission efficiency. Therefore, the width of the root of the fine grid is set within a reasonable range of 25μm-50μm to reduce the shading area of the fine grid while preventing the resistivity of the fine grid from being too high, affecting the current collection and transmission efficiency. Exemplarily, the width of the root of the fine grid is 25μm, 28μm, 30μm, 32μm, 35μm, 38μm, 40μm, 42μm, 45μm, 48μm or 50μm.

[0046] The width of the organic diffusion strips 2 located on either side of the fine grid is 30 μm to 100 μm. This prevents the organic diffusion strips 2 on either side of the fine grid from being too wide, thereby increasing the light-receiving area and improving photoelectric conversion efficiency. At the same time, the width of the organic diffusion strips 2 is kept moderate, thereby improving the adhesion between the fine grid and the first surface. For example, the width of the organic diffusion strips 2 located on either side of the fine grid is 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm.

[0047] In another embodiment, the gate line 1 includes a main grid extending along the second direction, and the width of the root of the main grid is 50μm-100μm. If the width of the root of the main grid is too large, it will result in a larger shading area, affecting the photoelectric conversion efficiency of the solar cell. If the width of the root of the main grid is too small, it will cause the contact resistance between the main grid and the first semiconductor layer 4 or the second semiconductor layer 7 to be high, affecting the current transmission efficiency. Therefore, the width of the root of the main grid is set within a reasonable range of 50μm-100μm to reduce the shading area of the main grid while preventing the resistivity of the main grid from being too high, affecting the current collection and transmission efficiency. Exemplarily, the width of the root of the main grid is 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm or 100μm.

[0048] The width of the organic diffusion strips 2 on either side of the busbar is 100 μm to 250 μm. This prevents the organic diffusion strips 2 on either side of the busbar from being too wide, thereby increasing the light-receiving area and improving photoelectric conversion efficiency. The width of the organic diffusion strips 2 is also kept moderate, improving the adhesion between the busbar and the first surface. Exemplarily, the width of the organic diffusion strips 2 on either side of the busbar is 100 μm, 120 μm, 150 μm, 180 μm, 200 μm, 220 μm, or 250 μm.

[0049] The first direction and the second direction intersect. The angle between the first direction and the second direction is not specifically limited. For example, the first direction and the second direction may be perpendicular. For another example, the angle between the first direction and the second direction may be greater than or equal to 60° and less than 90°.

[0050] In each of the above embodiments, for a solar cell without a busbar, the fine grids of the solar cell include first fine grids and second fine grids, and the first fine grids and the second fine grids are arranged alternately along the second direction. In this embodiment, the first fine grids and the second fine grids can be arranged continuously along the first direction or intermittently in multiple sections.

[0051] For a solar cell with a main grid, the fine grid of the solar cell includes a first fine grid and a second fine grid, and the main grid of the solar cell includes a first fine grid and / or a second main grid. In this embodiment, the first fine grid and the second fine grid can be arranged continuously and uninterruptedly along the first direction or can be discontinuously formed into multiple sections. In one case, the number of the first main grid and the second main grid are both multiple, and the multiple first main grids and the second main grids are arranged in sequence along the first direction. Any first fine grid and any second fine grid between adjacent first main grids and second main grids are arranged continuously and uninterruptedly along the first direction, and the multiple first fine grids are all electrically connected to the first main grid, and the multiple second fine grids are all electrically connected to the second main grid. In another case, when there is only one first main grid and one second main grid, at least one first fine grid is electrically connected to the first main grid, and at least one second fine grid is electrically connected to the second main grid.

[0052] In another embodiment, if Figure 1 and Figure 2 As shown, the first surface can have a textured structure, with the gate lines 1 and organic diffusion strips 2 formed on the textured structure. With this arrangement, the formation of the textured structure increases the surface area of the first surface, thereby increasing the contact area between the gate lines 1 and the organic diffusion strips 2 and the first surface, further improving the adhesion between the gate lines 1 and the organic diffusion strips 2, while also reducing the contact resistance of the gate lines 1, thereby ensuring the efficiency of current collection and transmission. Furthermore, the textured structure has a light-trapping effect, so when the first surface has a textured structure, it can reduce the reflectivity of light, allowing more light to be refracted from the light-facing surface into the substrate 6 and absorbed and utilized by the substrate 6, thereby improving the photoelectric conversion efficiency of the back-contact cell.

[0053] In some embodiments, the solar cell may further include a transparent conductive layer 3, which is disposed on the side of the first semiconductor layer 4 or the second semiconductor layer 7 facing away from the substrate 6. The transparent conductive layer 3 has a high electrical conductivity and can promptly conduct the collected carriers, thereby reducing the carrier recombination rate. Furthermore, it is possible to select whether to dispose the transparent conductive layer 3 on the side of the first semiconductor layer 4 facing away from the substrate 6, as needed. For example, when the first semiconductor layer 4 is doped polycrystalline silicon, the side of the first semiconductor layer 4 facing away from the substrate 6 may be provided with or without the transparent conductive layer 3. When the first semiconductor layer 4 is any one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon, the side of the first semiconductor layer 4 facing away from the substrate 6 may be provided with a transparent conductive layer 3. Similarly, it is possible to select whether to dispose the transparent conductive layer 3 on the side of the second semiconductor layer 7 facing away from the substrate 6, as needed. For example, when the second semiconductor layer 7 is doped polycrystalline silicon, a transparent conductive layer 3 may be provided on the side of the second semiconductor layer 7 away from the substrate 6, or a transparent conductive layer 3 may not be provided; when the second semiconductor layer 7 is any one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon, a transparent conductive layer 3 may be provided on the side of the second semiconductor layer 7 away from the substrate 6.

[0054] Moreover, when a transparent conductive layer 3 is provided on both the side of the first semiconductor layer 4 and the side of the second semiconductor layer 7 facing away from the substrate 6, an insulating groove can also be provided that penetrates the transparent conductive layer 3 along the thickness direction of the substrate 6, and the insulating groove separates the portion of the transparent conductive layer 3 corresponding to the first semiconductor layer 4 and the portion corresponding to the second semiconductor layer 7.

[0055] When the solar cell further includes a transparent conductive layer 3, the transparent conductive layer 3 is formed on the textured structure, and the grid lines 1 and the organic diffusion tape 2 are formed on the transparent conductive layer 3. This increases the contact area between the grid lines 1 and the organic diffusion tape 2 and the transparent conductive layer 3, further improving the adhesion between the grid lines 1 and the organic diffusion tape 2, while also reducing the contact resistance of the grid lines 1, thereby ensuring the efficiency of current collection and transmission.

[0056] Regarding the transparent conductive layer 3, the embodiment of the present invention does not specifically limit the material and thickness of the transparent conductive layer 3. For example, the material of the transparent conductive layer 3 may include at least one of fluorine-doped tin oxide, aluminum-doped zinc oxide, tin-doped indium oxide, tungsten-doped indium oxide, molybdenum-doped indium oxide, cerium-doped indium oxide, and indium hydroxide.

[0057] Illustratively, the thickness of the transparent conductive layer 3 may be greater than or equal to 10 nm and less than or equal to 100 nm.

[0058] Furthermore, the texture structure includes a tower base structure, a pyramid structure and / or an inverted pyramid structure. Since the average particle size of the conductive particles contained in the slurry used to form the gate line 1 is between 2μm and 8μm, and the proportion of conductive particles below 10 microns is greater than or equal to 80%, based on this, the height of the tower base structure, the pyramid structure and / or the inverted pyramid is less than or equal to 5μm, so that most of the conductive particles are of the same size as the texture structure, which not only increases the contact area between the conductive particles and the texture structure, but also further improves the adhesion of the gate line 1. For example, the height of the tower base structure, the pyramid structure and / or the inverted pyramid can be 1μm, 2μm, 3μm, 4μm or 5μm. Among them, the conductive particles can be silver, copper, aluminum, etc. In addition, the pyramid structure can be a pyramid shape with a rounded spire, a pyramid shape with a flattened spire, or a conventional pyramid shape with a spire angle.

[0059] In the case of a pyramidal texture, the organic matter in the organic diffusion band 2 is located at the bottom of the pyramid. During the gate line formation process, rapid annealing is performed to ensure that the organic matter in the organic diffusion band 2 remains within a reasonable range only at the bottom of the pyramid, with no organic matter remaining in the upper half of the pyramid. This reduces organic matter residue and ensures a good electrical interconnection effect.

[0060] In addition, if Figure 2 As shown, the ratio of the height of gate line 1 to the width at its base is 0.2 to 0.6. The height of gate line 1 refers to the distance from its base to its top. This arrangement minimizes the resistance of gate line 1 while maintaining its cross-sectional area, thereby improving current collection and transmission. Furthermore, it reduces slurry usage and prevents waste.

[0061] In the above embodiment, the ratio of the height of the gate line 1 to the width of the gate line 1 at its root can be 0.2, 0.3, 0.4, 0.5 or 0.6. For example, the width of the gate line 1 at its root is 31 μm and the height is 14 μm; the width of the gate line 1 at its root is 35 μm and the height is 10 μm.

[0062] In terms of the types of organic matter, the slurry used to form the gate lines 1 contains multiple organic matter, and the organic diffusion band 2 includes any one of the multiple organic matter in the slurry. Among the multiple organic matter contained in the slurry used to form the gate lines 1, some organic matter diffuses faster, while others diffuse slower. Therefore, the organic diffusion band 2 may include any one of the organic matter in the slurry.

[0063] The slurry used to form the gate lines 1 contains a variety of organic substances including diethylene glycol butyl ether, diethylene glycol butyl ether acetate and / or terpineol, and the weight percentage of the conductive particles in the slurry is 85%-95%.

[0064] like Figure 3 As shown, in one specific embodiment, the solar cell includes a first semiconductor layer 4 formed on a first surface, a gateline 1 formed on the first surface, a second semiconductor layer 7 formed on a second surface, and the gateline 1 formed on the second surface. The first semiconductor layer 4 and the second semiconductor layer 7 have opposite conductivity types. The gateline 1 formed on the first surface is electrically connected to the first semiconductor layer 4, and the gateline 1 formed on the second surface is electrically connected to the second semiconductor layer 7. Using this technical solution, the first semiconductor layer 4 and the second semiconductor layer 7 are located on the first surface and the second surface, respectively. The first semiconductor layer 4 and the second semiconductor layer 7 are relatively far apart, which reduces the carrier recombination rate and helps improve the photoelectric conversion efficiency.

[0065] Among them, the size, shape, type and other characteristics of the gate line 1 formed on the second surface can refer to the relevant description of the gate line 1 formed on the first surface, and the width, proportion and other characteristics of the organic diffusion band 2 of the gate line 1 formed on the second surface can refer to the relevant description of the organic diffusion band 2 on both sides of the gate line 1 formed on the first surface, which will not be repeated here.

[0066] like Figure 4 As shown, in another specific embodiment, the solar cell includes a first semiconductor layer 4 and a second semiconductor layer 7 formed on the first surface, as well as a gate line 1 formed on the first surface. The first semiconductor layer 4 and the second semiconductor layer 7 have opposite conductivity types; a portion of the gate line 1 formed on the first surface is electrically connected to the first semiconductor layer 4, while another portion of the gate line 1 formed on the first surface is electrically connected to the second semiconductor layer 7. With this technical solution, both the first semiconductor layer 4 and the second semiconductor layer 7 are formed on the first surface, avoiding the problem of light blocking by the gate line 1, reducing light loss, and improving photoelectric utilization.

[0067] In the above two embodiments, the material of the substrate 6 can be selected from materials such as silicon (Si) or germanium (Ge) or materials such as gallium arsenide (GaAs). Obviously, in terms of conductivity type, the substrate 6 can be an intrinsic conductive substrate, an n-type conductive substrate or a p-type conductive substrate. Preferably, the substrate 6 is a p-type conductive substrate or an n-type conductive substrate. Compared with the intrinsic conductive substrate, the p-type conductive substrate or the n-type conductive substrate has better conductivity, so that the final back-contact battery has a lower bulk resistivity, thereby improving the efficiency of the back-contact battery.

[0068] For example, the substrate 6 can be a p-type substrate or an n-type substrate. The n-type substrate has the advantages of long minority carrier lifetime, no light decay, and good weak light performance.

[0069] In addition, the materials of the first semiconductor layer 4 and the second semiconductor layer 7 can be silicon (Si), germanium (Ge), silicon carbide (SiCx) or gallium arsenide (GaAs), etc. Taking the example that the materials of the first semiconductor layer 4 and the second semiconductor layer 7 are both silicon (Si), the first semiconductor layer 4 can be any one of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The second semiconductor layer 7 can be any one of doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The first semiconductor layer 4 can be additionally formed on the substrate 6 by a deposition technique, or can be formed within the substrate 6 by diffusion, ion implantation, etc.

[0070] In some examples, the first semiconductor layer 4 includes a doped polysilicon layer. In this case, the doped polysilicon layer has higher carrier transport properties than the doped amorphous silicon layer. Therefore, when the first semiconductor layer 4 is a doped polysilicon layer, the carrier transport efficiency is higher, which is conducive to improving the photoelectric conversion efficiency of the solar cell.

[0071] In terms of conductivity type, the first semiconductor layer 4 may be an n-type doped layer, and the second semiconductor layer 7 may be a p-type doped layer; or, the first semiconductor layer 4 may be a p-type doped layer, and the second semiconductor layer 7 may be an n-type doped layer.

[0072] like Figure 3 and Figure 4 As shown, the solar cells in the above two embodiments may further include a first interface passivation layer 5, which is located at least between the first semiconductor layer 4 and the substrate 6. In this case, the passivation contact structure composed of the first interface passivation layer 5 and the first semiconductor layer 4 has an excellent interface passivation effect, and can achieve selective collection of carriers, reduce the carrier recombination rate in the corresponding area between the first surface of the substrate 6 and the first semiconductor layer 4, and further improve the photoelectric conversion efficiency of the back contact cell. The material and thickness of the first interface passivation layer 5 can be set according to the material of the first semiconductor layer 4 and actual needs, and are not specifically limited here.

[0073] The material of the first interface passivation layer 5 can be determined based on the material of the first semiconductor layer 4. For example, when the first semiconductor layer 4 includes a doped polycrystalline silicon layer, the first interface passivation layer 5 is a tunneling oxide layer. For another example, when the first semiconductor layer 4 includes a doped amorphous silicon layer and / or doped microcrystalline silicon, the first interface passivation layer 5 includes an intrinsic amorphous silicon layer and / or doped microcrystalline silicon. Furthermore, the embodiments of the present invention do not specifically limit the material of the first interface passivation layer 5.

[0074] like Figure 3 and Figure 4 As shown, the above-mentioned solar cell may also include a second interface passivation layer 8, which is located at least between the second semiconductor layer 7 and the substrate 6. The projection of the second interface passivation layer 8 on the substrate 6 may overlap with the projection of the second semiconductor layer 7 on the substrate 6. In this case, the passivation contact structure composed of the second interface passivation layer 8 and the second semiconductor layer 7 can achieve selective collection of carriers and reduce the carrier recombination rate in the corresponding areas of the substrate 6 and the second semiconductor layer 7. The material and thickness of the second interface passivation layer 8 can be set according to the material of the second semiconductor layer 7 and actual needs, and are not specifically limited here. For example: when the material of the second semiconductor layer 7 includes any one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon, the second interface passivation layer 8 includes one or more of an intrinsic amorphous silicon layer, an intrinsic microcrystalline silicon layer, and an intrinsic nanocrystalline silicon layer.

[0075] As for the thickness of the second interface passivation layer 8, since the thickness of the second interface passivation layer 8 will affect its own transmission resistance and passivation effect, and thus affect the forward leakage loss and reverse breakdown voltage of the solar cell, the thickness of the second interface passivation layer 8 can be determined according to the requirements of the forward leakage loss and reverse breakdown voltage of the back contact battery in actual application scenarios, and no specific limitation is made here.

[0076] Exemplarily, the solar cell can be an HJT (Heterojunction Technology) cell, in which the first semiconductor layer 4 is formed on the first surface, and the second semiconductor layer 7 is formed on the second surface, the first semiconductor layer 4 includes doped amorphous silicon and / or doped microcrystalline silicon, and the first interface passivation layer 5 includes intrinsic amorphous silicon and / or intrinsic microcrystalline silicon; the second semiconductor layer 7 can include doped amorphous silicon and / or doped microcrystalline silicon, and the second interface passivation layer 8 includes intrinsic amorphous silicon and / or intrinsic microcrystalline silicon.

[0077] Exemplarily, the solar cell can be a double-sided hybrid cell, in which the first semiconductor layer 4 is formed on the first surface and the second semiconductor layer 7 is formed on the second surface, the first semiconductor layer 4 includes doped amorphous silicon and / or doped microcrystalline silicon, and the first interface passivation layer 5 includes intrinsic amorphous silicon and / or intrinsic microcrystalline silicon; the second semiconductor layer 7 may include doped polycrystalline silicon, the second interface passivation layer 8 includes a tunneling oxide, and the second semiconductor layer 7 and the second interface passivation layer 8 can be formed as a polycrystalline silicon finger structure (poly-finger), that is, a local strip-shaped second semiconductor layer 7 and second interface passivation layer 8 passivation structure is formed at the position corresponding to the second surface metallization.

[0078] For example, the solar cell may be a hybrid back contact cell, the first semiconductor layer 4 and the second semiconductor layer 7 may both be formed on the first surface, the first semiconductor layer 4 includes doped amorphous silicon, and the first interface passivation layer 5 includes intrinsic amorphous silicon. Figure 4 The gate line 1 is formed on the transparent conductive layer 3, and the organic diffusion bands 2 on both sides are also on the surface of the transparent conductive layer 3, wherein the transparent conductive layer 3 is formed conformally with the substrate 6 of the solar cell. The substrate 6 of the solar cell has a concave portion, such as Figure 4 In the right portion shown, the bottom surface of the recessed portion has at least the first texture structure. The organic diffusion band 2 of the gate line 1 on the first semiconductor layer 4 is controllable, ensuring that the ratio of the width of the organic diffusion band 2 on either side of the gate line 1 to the width of the gate line 1 at its base is between 1 and 3, and can be, for example, 1, 1.5, 1.8, 2, 2.5, 2.5, 2.8, or 3. Furthermore, the width of the organic diffusion band 2 cannot exceed the width of the recessed portion to prevent leakage, obstruction, and other problems caused by the spread of organic matter.

[0079] And in Figure 4 The left side of the second semiconductor layer 7 may be a polysilicon layer and a tunnel oxide layer passivation layer, that is, the second semiconductor layer 7 is a polysilicon layer, and the second interface passivation layer 8 is a tunnel oxide layer. The substrate of the solar cell below the second semiconductor layer 7 and the second interface passivation layer 8 has a second texture structure. The first texture structure and the second texture structure are different. For example, the first texture structure may be a pyramid structure, and the second texture structure may be a tower base structure.

[0080] In another embodiment, Figure 5As shown, the substrate 6 of the solar cell includes a first area 9 and a second area 10 extending along a first direction on the first surface, and the first area 9 and the second area 10 are alternately arranged in sequence along the second direction. Among them, the first area 9 has a first texture structure, and the second area 10 has a second texture structure. The first texture structure and the second texture structure are different. Exemplarily, the first texture structure can be a pyramid-shaped structure, and the second texture structure can be a tower base structure. There is a first grid line on the first texture structure, and the organic diffusion band of the first grid line does not extend to the boundary of the first area 9 and the second area 10. In this way, the organic matter and conductive particles of the first grid line can be prevented from diffusing to the second area 10, resulting in the semiconductor layer in the first area 9 and the semiconductor layer in the second area 10 being recombined, which poses a risk of leakage.

[0081] Considering that if the distance between the edge of the organic diffusion band 2 of the first gate line and the boundary between the first region 9 and the second region 10 is too large, the width of the first gate line will be reduced, the contact resistance of the first gate line will be increased, and the current transmission efficiency will be affected; if the distance between the edge of the organic diffusion band 2 of the first gate line and the boundary between the first region 9 and the second region 10 is too small, the semiconductor layer in the first region 9 and the semiconductor layer in the second region 10 may recombine, resulting in serious leakage. Therefore, the distance between the edge of the organic diffusion band 2 of the first gate line and the boundary between the first region 9 and the second region 10 is set within a reasonable range of 100μm-200μm to ensure the current transmission efficiency while preventing serious leakage between the semiconductor layer in the first region 9 and the semiconductor layer in the second region 10. For example, the distance between the edge of the organic diffusion band 2 of the first gate line and the boundary between the first region 9 and the second region 10 is 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, or 200μm.

[0082] The present invention also provides a photovoltaic module comprising at least one solar cell and an encapsulation layer according to any of the above embodiments. Considering that the encapsulation layer also contains organic matter, and that the organic matter contained in the encapsulation layer diffuses into the organic diffusion band 2, it is difficult to distinguish whether the organic matter in the organic diffusion band 2 originates from the grid line 1 or the encapsulation layer. Therefore, the encapsulation layer is made of a different material than the organic matter in the organic diffusion band 2, thereby facilitating identification of the edge of the organic diffusion band 2 and whether the organic matter in the organic diffusion band 2 originates from the grid line 1 or the encapsulation layer.

[0083] Compared with the prior art, the beneficial effects of the photovoltaic module provided by the embodiment of the present invention are the same as the beneficial effects of the above-mentioned solar cell, which will not be described in detail here.

[0084] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0085] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A solar cell, characterized in that: The invention comprises a first surface and a second surface opposite to each other, a gate line formed on the first surface and an organic diffusion belt formed on both sides of the gate line, wherein the organic diffusion belt comprises an organic substance in a slurry used to form the gate line; One end of the gate line close to the first surface is the root of the gate line, and the ratio of the width of the organic diffusion zone located on either side of the gate line to the width of the gate line root is 1-3.

2. The solar cell according to claim 1, wherein The gate lines include thin gates extending along a first direction; The width of the root of the fine grid is 25 μm-50 μm; and / or the width of the organic diffusion zone located on either side of the fine grid is 30 μm-100 μm.

3. The solar cell according to claim 1, wherein The gate line includes a main gate extending along the second direction; The width of the root of the main grid is 50 μm-100 μm; and / or the width of the organic diffusion zone located on either side of the main grid is 100 μm-250 μm.

4. The solar cell according to claim 1, wherein The first surface has a texture structure, and the gate line and the organic diffusion band are formed on the texture structure; and / or the first surface has a texture structure and a transparent conductive layer formed on the texture structure, and the gate line and the organic diffusion band are formed on the transparent conductive layer.

5. The solar cell according to claim 4, wherein The texture structure includes a tower base structure, a pyramid structure and / or an inverted pyramid structure; The height of the tower base structure, pyramid structure and / or inverted pyramid structure is less than or equal to 5 μm.

6. The solar cell according to claim 5, characterized in that The texture structure is a pyramid structure, and the organic matter of the organic diffusion zone is located at the bottom of the pyramid structure.

7. The solar cell according to claim 1, wherein The ratio of the height of the gate line to the width of its root is 0.2 to 0.

6.

8. The solar cell according to claim 1, wherein The paste for forming the gate line contains a plurality of organic substances, and the organic diffusion zone includes any one of the plurality of organic substances in the paste.

9. The solar cell according to claim 1, wherein The solar cell also includes a first semiconductor layer formed on the first surface, a second semiconductor layer formed on the second surface, and a gate line formed on the second surface, wherein the first semiconductor layer and the second semiconductor layer have opposite conductivity types; the gate line formed on the first surface is electrically connected to the first semiconductor layer, and the gate line formed on the second surface is electrically connected to the second semiconductor layer.

10. The solar cell according to claim 1, wherein The solar cell also includes a first semiconductor layer and a second semiconductor layer formed on the first surface, and the first semiconductor layer and the second semiconductor layer have opposite conductivity types; a portion of the gate line formed on the first surface is electrically connected to the first semiconductor layer, and another portion of the gate line formed on the first surface is electrically connected to the second semiconductor layer.

11. The solar cell according to claim 9 or 10, characterized in that The first semiconductor layer includes any one of doped amorphous silicon, doped microcrystalline silicon, doped nanosilicon, and doped polycrystalline silicon; and / or, the second semiconductor layer includes any one of doped amorphous silicon, doped microcrystalline silicon, doped nanosilicon, and doped polycrystalline silicon; and / or, the solar cell also includes a first interface passivation layer located at least between the first semiconductor layer and the substrate of the solar cell; and / or, the solar cell also includes a second interface passivation layer located at least between the second semiconductor layer and the substrate of the solar cell; and / or, the solar cell also includes a transparent conductive layer covering the first semiconductor layer and the second semiconductor layer on the side facing away from the substrate of the solar cell.

12. The solar cell according to any one of claims 1 to 10, characterized in that The substrate of the solar cell includes, on the first surface, a first region and a second region extending along a first direction and alternately arranged along a second direction, the first region having a first texture structure, the second region having a second texture structure, and the first texture structure and the second texture structure are different; A first grid line is provided on the first texture structure, and an organic diffusion zone of the first grid line does not extend to the boundary between the first region and the second region.

13. The solar cell according to claim 12, wherein: The distance between the edge of the organic diffusion strip of the first gate line and the boundary between the first region and the second region is 100 μm-200 μm.

14. A photovoltaic module, characterized in that: The method comprises at least one solar cell according to any one of claims 1 to 13 and an encapsulation layer, wherein the material of the encapsulation layer is different from the organic matter of the organic diffusion band.

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