Solar cell substrate and solar cell

Abstract

The utility model relates to the field of photovoltaic technology, and provides a solar cell substrate and a solar cell, the surface of the solar cell substrate is provided with a plurality of first tower footing structures and a plurality of second tower footing structures; the surface of the solar cell substrate comprises a grid line coverage area and an exposed area, the plurality of first tower footing structures are arranged in the grid line coverage area, and the plurality of second tower footing structures are arranged in the exposed area; the top surface, away from the solar cell substrate, of the first tower footing structure and the top surface, away from the solar cell substrate, of the second tower footing structure protrude out of the surface of the solar cell substrate, and the distance that the top surface of the first tower footing structure protrudes out of the surface of the solar cell substrate is smaller than the distance that the top surface of the second tower footing structure protrudes out of the surface of the solar cell substrate. The solar cell substrate can reduce slurry contact dead angles and improve the contact effect of the grid lines and the solar cell substrate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, in particular to a solar cell substrate and a solar cell. BACKGROUND

[0002] Solar energy has become one of the fastest growing renewable energy sources due to its advantages such as cleanness, safety and abundant resources, and photovoltaic power generation is one of the most important utilization ways of solar energy. In the traditional technology, the solar cell mostly adopts a back tower base rough surface structure. However, the tower base rough surface structure has poor contact with the paste during the preparation of the grid lines, the contact resistance between the grid lines and the cell substrate is large, and the conversion efficiency of the solar cell is affected. CONTENT OF THE UTILITY MODEL

[0003] Therefore, an embodiment of the present application provides a solar cell substrate and a solar cell capable of improving the contact resistance of the grid lines.

[0004] In a first aspect, the present application provides a solar cell substrate, wherein a surface of the solar cell substrate is provided with a plurality of first tower base structures and a plurality of second tower base structures.

[0005] The surface of the solar cell substrate comprises a grid line coverage area and an exposed area, the plurality of first tower base structures are arranged in the grid line coverage area, and the plurality of second tower base structures are arranged in the exposed area; the first tower base structure and the second tower base structure away from the top surface of the solar cell substrate respectively protrude from the surface of the solar cell substrate, and the distance by which the top surface of the first tower base structure protrudes from the surface of the solar cell substrate is less than the distance by which the top surface of the second tower base structure protrudes from the surface of the solar cell substrate.

[0006] In some embodiments, the minimum distance between the first tower base structure and the second tower base structure in the thickness direction of the solar cell substrate is 1 μm to 2 μm.

[0007] In some embodiments, the height of the first tower base structure is 0.5 μm to 1 μm.

[0008] In some embodiments, the height of the second tower base structure is 0.5 μm to 1.5 μm.

[0009] In some embodiments, the area of the top surface of the first tower base structure is greater than the area of the top surface of the second tower base structure.

[0010] In some embodiments, the top surface of the first tower base structure is rectangular, and the side length of the top surface is 13 μm to 16 μm.

[0011] In some embodiments, the top surface of the second tower base structure is rectangular, and the side length of the top surface is 5μm to 9μm.

[0012] In some embodiments, the bottom surface of the first tower base structure is rectangular, and the side length of the bottom surface is 13.5μm~17μm.

[0013] In some embodiments, the bottom surface of the second tower base structure is rectangular, and the side length of the bottom surface is 5.5μm to 10μm.

[0014] In some embodiments, the solar cell substrate has multiple pyramid structures on the side surface away from the first and second tower base structures.

[0015] In a second aspect, this application provides a solar cell comprising a solar cell substrate as described in the first aspect.

[0016] In some embodiments, the solar cell further includes grid lines that cover the grid line coverage area in the solar cell substrate.

[0017] In some implementations, the height of the first tower base structure is less than 0.4 times the height of the grid line.

[0018] In some embodiments, the top surface of the first tower base structure is rectangular, and the side length of the top surface is 0.4 to 0.7 times the width of the grid line.

[0019] Compared with traditional technologies, this application has at least the following beneficial effects:

[0020] In this application, the distance between the protruding surface of the first tower base structure in the solar cell substrate and the distance between the protruding surface of the second tower base structure are lower. The multiple first tower base structures in the grid line coverage area have a flatter structure than the multiple second tower base structures in the exposed area. This reduces dead corners where the paste cannot reach during the grid line printing process, allowing the paste to better contact the solar cell substrate, resulting in better current to the solar cell and improving the photoelectric conversion efficiency of the solar cell. Attached Figure Description

[0021] Figure 1 This is a cross-sectional schematic diagram of a solar cell substrate provided in one embodiment of this application;

[0022] Figure 2 This is a schematic diagram of a solar cell substrate having a first tower base structure and a second tower base structure, provided in one embodiment of this application.

[0023] Figure 3 This is a schematic diagram of the structure of a solar cell provided in one embodiment of this application.

[0024] 100 - solar cell substrate; 110 - first tower base structure; 120 - second tower base structure; 130 - pyramid structure; 140 - front passivation layer; 150 - anti-reflection layer; 160 - front electrode; 170 - poly multi-crystalline silicon layer; 180 - back surface coating layer; 190 - back electrode. DETAILED DESCRIPTION

[0025] The application will be described in further detail with reference to the drawings, embodiments and examples, which are presented for the purpose of illustration only and are not intended to limit the scope of the application. These embodiments and examples are presented solely for the purposes of explanation and should not be considered necessary to practice the application. It will be apparent to those skilled in the art that numerous modifications and variations can be made to the present application without departing from the scope of the application. Accordingly, the application is not limited to the embodiments and examples described herein but is intended to cover all alternatives falling within the scope of the application. In addition, in the following description, numerous specific details are given to provide a thorough understanding of the application. It will be apparent, however, to those skilled in the art that the application can be practiced without one or more of these specific details.

[0026] It should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like, indicate orientations or positional relationships based on the orientations or positional relationships as shown in the drawings, and are merely used for convenience in describing the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the application.

[0027] In the description of the application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" and "provided" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the meaning of the above terms in the application can be understood according to the specific circumstances.

[0028] In the present application, "optionally", "optional" and "optional" mean that it can or can not be present, i.e. it means to select either of the two parallel schemes "yes" or "no". If there are multiple "options" in a technical solution, and there is no special description, and there is no contradictory relationship or mutual restriction, each "option" is independent.

[0029] In the present application, the technical features described in an open way include both the closed technical solutions consisting of the listed features and the open technical solutions containing the listed features.

[0030] The terms "first", "second", and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", and the like only serve the purpose of non-exhaustive enumeration description, and should be understood as not constituting a closed limitation on the quantity.

[0031] All documents mentioned in the present application are cited as references in the present application, as if each document is cited as a reference individually. Unless and to the extent that the cited documents conflict with the application purpose and / or technical solutions of the present application, the cited documents are cited in the present application in their entirety and for all purposes. When the present application refers to the cited documents, the definitions of the relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the present application refers to the cited documents, the examples and preferred modes of the cited relevant technical features can also be incorporated into the present application as references, but are limited to the implementation of the present application. It should be understood that when the cited content conflicts with the description in the present application, the present application is given priority or is modified adaptively according to the description in the present application.

[0032] In the conventional technology, the contact area of the tower base and the slurry is increased by reducing the size of the tower base. However, as the size of the tower base is reduced, the contact dead angle of the slurry and the tower base increases, which affects the contact of the slurry and the tower base, the contact resistance increases, and the photoelectric conversion efficiency of the solar cell is affected.

[0033] Based on this, the first aspect of the present application provides a solar cell substrate, as shown in Figure 1 and Figure 2 As shown in the drawings, the surface of the solar cell substrate 100 is provided with a plurality of first tower base structures 110 and a plurality of second tower base structures 120.

[0034] The surface of the solar cell substrate 100 includes a grid line covered area and an exposed area, the plurality of first tower base structures 110 are arranged in the grid line covered area, and the plurality of second tower base structures 120 are arranged in the exposed area; the top surfaces of the first tower base structures 110 and the second tower base structures 120 away from the top surface of the solar cell substrate 100 respectively protrude from the surface of the solar cell substrate 100, and the distance a of the top surface of the first tower base structure 110 protruding from the surface of the solar cell substrate 100 is less than the distance b of the top surface of the second tower base structure 120 protruding from the surface of the solar cell substrate 100. Wherein, the top surfaces of the first tower base structure 110 and the second tower base structure 120 away from one side surface of the solar cell substrate 100 are respectively the top surfaces.

[0035] The distance from the protruding surface of the first tower base structure 110 to the protruding surface of the second tower base structure 120 in the solar cell substrate 100 is less than the distance from the protruding surface of the second tower base structure 120, and the plurality of first tower base structures 110 in the grid line coverage area has a relatively flat structure relative to the plurality of second tower base structures 120 in the exposed area, which reduces the dead angle of the paste that cannot be contacted during the printing of the grid line, and the paste can better contact the solar cell substrate 100, so that the solar cell has better current and improves the photoelectric conversion efficiency of the solar cell.

[0036] It can be understood that the grid line coverage area in the present application refers to the area where the grid line is arranged in the solar cell, and the area where the grid line is arranged is in contact with the solar cell substrate 100 through the functional layer of the solar cell. Further, the exposed area in the present application refers to the area where the grid line is not arranged.

[0037] In some embodiments, as shown in Figure 1 and Figure 2 , the minimum distance c between the first tower base structure 110 and the second tower base structure 120 in the thickness direction of the solar cell substrate 100 is 1 μm to 2 μm, for example, it can be 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm or 2.0 μm. It can be understood that the minimum distance c between the first tower base structure 110 and the second tower base structure 120 in the thickness direction of the solar cell substrate 100 is the distance between the bottom surface of the first tower base structure 110 and the bottom surface of the second tower base structure 120.

[0038] In some embodiments, as shown in Figure 1 and Figure 2 , the height a of the first tower base structure 110 is 0.5 μm to 1 μm, for example, it can be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm or 1.0 μm. The present application selects the size of the first tower base structure 110 in the direction away from the solar cell substrate 100 as described above, thereby effectively ensuring the flatness of the solar cell substrate 100 in the grid line coverage area, further avoiding the contact dead angle of the paste, and improving the contact effect of the paste with the solar cell substrate 100.

[0039] It can be understood that the second tower base structure 120 in the present application is in the exposed area, and the size of the second tower base structure 120 can not be specifically required and specially limited, and can be reasonably adjusted according to the requirements of the solar cell. For example, in some embodiments, as shown in Figure 1 and Figure 2As shown, the height d of the second tower base structure 120 is 0.5 μm to 1.5 μm, for example, can be 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm or 1.5 μm.

[0040] In some embodiments, the area of the top surface of the first tower base structure 110 is greater than the area of the top surface of the second tower base structure 120. In the present application, the area of the top surface of the first tower base structure 110 is greater than the area of the top surface of the second tower base structure 120, which further improves the flatness of the solar cell substrate 100 in the grid line coverage area. Specifically, the first tower base structure 110 has a lower height and a relatively larger top surface area relative to the second tower base structure 120, which reduces the number of inclined surfaces in the second tower base structure 120 of the same area, and the second tower base structure 120 adjacent to the grid line coverage area has a higher inclined surface, which can compensate for the contact area of the paste with the solar cell, and does not reduce the contact area of the formed grid line with the solar cell substrate 100, and because the grid line coverage area is recessed relative to the exposed area, it can constrain the lateral flow of the paste, thereby reducing the grid line collapse and improving the aspect ratio of the grid line, which is beneficial to the reduction of the grid line resistance, thereby improving the cell current performance. That is, the first tower base structure 110 has better flatness relative to the second tower base structure 120, so that the contact dead angle of the paste with the first tower base structure 110 is small during the paste contact process, and the contact effect of the formed grid line with the solar cell substrate 100 is good.

[0041] In some embodiments, the top surface of the first tower base structure 110 is rectangular, and the length e of the top surface is 13 μm to 16 μm, for example, can be 13.0 μm, 13.5 μm, 14.0 μm, 14.5 μm, 15.0 μm, 15.5 μm or 16.0 μm. The present application selects the length of the top surface of the first tower base structure 110 as above, which can make the first tower base structure 110 have better flatness, thereby improving the contact effect of the grid line with the solar cell substrate 100.

[0042] In some embodiments, the top surface of the second tower base structure 120 is rectangular, and the length f of the top surface is 5 μm to 9 μm, for example, can be 5.0 μm, 5.5 μm, 6.0 μm, 6.5 μm, 7.0 μm, 7.5 μm, 8.0 μm, 8.5 μm or 9.0 μm.

[0043] It can be understood that the length of the side of the first tower base structure 110 and the second tower base structure 120 can refer to the length of the length direction of the top surface, or the length of the width direction. Further, the length direction side length of the first tower base structure 110 can be equal to the width direction side length, or can not be equal. Similarly, the length direction side length of the second tower base structure 120 can be equal to the width direction side length, or can not be equal.

[0044] In some embodiments, the bottom surface of the first tower base structure 110 is rectangular, and the length of the bottom surface is 13.5 μm to 17 μm, for example, can be 13.5 μm, 14.0 μm, 14.5 μm, 15.0 μm, 15.5 μm, 16.0 μm, 16.5 μm or 17.0 μm.

[0045] In some embodiments, the bottom surface of the second tower base structure 120 is rectangular, and the length of the bottom surface is 5.5 μm to 10 μm, for example, can be 5.5 μm, 6.0 μm, 6.5 μm, 7.0 μm, 7.5 μm, 8.0 μm, 8.5 μm, 9.0 μm, 9.5 μm or 10.0 μm.

[0046] In some embodiments, the solar cell substrate 100 is provided with a plurality of pyramid structures 130 on the side surface away from the first tower base structure 110 and the second tower base structure 120. It can be understood that the plurality of pyramid structures 130 are provided on the side surface of the solar cell substrate 100 away from the first tower base structure 110 and the second tower base structure 120 in the present application, forming a pyramid texture, effectively ensuring the photoelectric conversion efficiency of the solar cell.

[0047] Exemplarily, a preparation method of the above-mentioned solar cell substrate 100 is provided, comprising the following steps:

[0048] S1, selecting a silicon wafer subjected to texturing and boron diffusion, placing the silicon wafer on a pipeline corresponding to a screen grid line pattern, i.e. a grid line covered area, removing the BSG (borosilicate glass) protective layer of the grid line covered area by immersing the pipeline in an HF solution, and then cleaning and drying;

[0049] S2, performing first alkali etching treatment on the silicon wafer obtained in step S1 to form a tower base structure in the grid line covered area;

[0050] S3, removing the BSG in the exposed area by a backside BSG chain machine table of the silicon wafer obtained in step S2;

[0051] S4, the silicon wafer treated in step S3 is subjected to a second alkali etching treatment. In the second alkali etching treatment, the exposed area is not subjected to the first alkali etching treatment and a second tower base structure 120 is formed; the gate line covered area is subjected to the first alkali etching treatment and the second alkali etching treatment, so that a first tower base structure 110 with a deeper etching depth and a larger tower base size is further formed, thereby obtaining the solar cell substrate 100.

[0052] In some embodiments, the mass concentration of the HF solution in step S1 can be 30% to 49%.

[0053] In some embodiments, the first alkali etching treatment includes a tri-peak additive and sodium hydroxide (the mass concentration of sodium hydroxide in the solution can be 0.9% to 1.5%). Optionally, the mass concentration of the tri-peak additive in the solution can be 0.7% to 1%. The mass concentration of sodium hydroxide in the solution can be 0.9% to 1.5%.

[0054] In some embodiments, the reaction time of the first alkali etching treatment is 100s to 150s, and the temperature is 55°C to 60°C.

[0055] In some embodiments, the second alkali etching treatment includes a tri-peak additive and sodium hydroxide. Optionally, the mass concentration of the tri-peak additive in the solution can be 0.7% to 1.2%. The mass concentration of sodium hydroxide in the solution can be 0.9% to 1.5%.

[0056] In some embodiments, the reaction time of the second alkali etching treatment is 120s to 160s, and the temperature is 55°C to 60°C.

[0057] It can be understood that a sacrificial layer can be formed on the exposed area of the silicon wafer after the BSG layer is removed during the preparation process, so that the first alkali etching treatment is performed on the gate line covered area. That is, the solar cell substrate 100 structure in the present application can be formed in different ways.

[0058] The second aspect of the present application provides a solar cell, which includes the solar cell substrate 100 of the first aspect.

[0059] In some embodiments, the solar cell further includes a gate line, which covers the gate line covered area in the solar cell substrate 100.

[0060] In some embodiments, the distance between the bottom surface and the top surface of the first tower base structure 110 is less than 0.4 times the height of the gate line.

[0061] In some embodiments, the length of the side of the top surface of the first tower base structure 110 is 0.4 times to 0.7 times the width of the gate line, for example, it can be 0.4 times, 0.5 times, 0.6 times or 0.7 times.

[0062] It can be understood that the application does not make specific requirements and special limitations on the type of solar cell, and the solar cell also includes other functional layers arranged on the solar cell substrate 100, such as a tunneling oxide layer, a passivation layer, and an electrode pattern, etc. In some embodiments, the solar cell can be a TOPCon cell or a PERC cell.

[0063] Optionally, taking a TOPCon (Tunnel Oxide Passivated Contact) solar cell as an example, the solar cell includes a solar cell substrate 100, a first passivation layer and a first electrode pattern arranged on the front side of the solar cell substrate 100, and a tunneling oxide layer, an N-type doped polysilicon layer, a second passivation layer, and a second electrode pattern arranged on the back side of the substrate. Among them, the front side of the solar cell substrate 100 refers to the side surface with a pyramid structure 130, which is close to the light-receiving surface of the solar cell. The light-receiving surface represents the side surface on which the light irradiates the solar cell. The back side of the solar cell substrate 100 refers to the side surface with the first tower base structure 110 and the second tower base structure 120, which is close to the back light surface of the solar cell. The back light surface represents the side surface on which the light does not irradiate the solar cell, and the back light surface is arranged opposite to the light-receiving surface.

[0064] In the following examples and comparative examples, all raw materials can be purchased in commercial form, and in order to maintain the reliability of the experiment, the raw materials used in the following examples and comparative examples all have the same physical and chemical parameters or are prepared by the same treatment method.

[0065] Example 1

[0066] S1, select a 210mm×182mm size silicon wafer after texturing + boron expansion, place the silicon wafer on the pipeline corresponding to the screen grid line patterning, that is, the grid line covered area, remove the BSG protective layer in the grid line covered area by the HF solution with a mass concentration of 45% immersed along the pipeline gap, and then clean and dry;

[0067] S2, the silicon wafer treated in step S1 is subjected to first alkali etching treatment to form a tower base structure on the grid line covered area of the silicon wafer. The first alkali etching treatment adopts a liquid medicine composed of sodium hydroxide with a mass concentration of 1.1% and a BPL-819B type additive with a mass concentration of 0.9%, the reaction time is 100s, and the reaction temperature is 58℃;

[0068] S3, the back side of the silicon wafer treated in step S2 is removed by the BSG chain type machine table, and the BSG in the exposed area is removed;

[0069] S5, the silicon wafer treated in step S3 is subjected to a second alkali etching treatment, the alkali etching solution in the second alkali etching treatment is composed of a 0.8% (mass concentration) BPL-819B type additive and a 1.2% (mass concentration) sodium hydroxide solution, the reaction time is 150 s, and the reaction temperature is 60°C, so as to form a first tower base structure 110 in the gate line coverage area and a second tower base structure 120 in the exposed area, thereby preparing the solar cell substrate 100.

[0070] The distance between the bottom surface of the second tower base structure 120 and the bottom surface of the first tower base structure 110 is 1.5 μm. The height of the first tower base structure 110 is 0.75 μm. The height of the second tower base structure 120 is 1 μm. The side length of the top surface of the first tower base structure 110 is 15 μm. The side length of the top surface of the second tower base structure 120 is 7 μm. The side length of the bottom surface of the first tower base structure 110 is 16 μm. The side length of the bottom surface of the second tower base structure 120 is 8 μm.

[0071] Comparative Example 1

[0072] S1, a 210 mm x 182 mm silicon wafer subjected to texturing and boron diffusion is selected, and the back surface BSG is removed by a chain machine using a 32% (mass concentration) HF solution.

[0073] S2, the silicon wafer treated in step S1 is subjected to an alkali etching treatment, the alkali etching solution is composed of a 1% (mass concentration) sodium hydroxide solution and a 0.8% (mass concentration) BPL-819B type additive, the reaction time is 220 s, and the reaction temperature is 58°C, so as to form a tower base structure on the silicon wafer, thereby preparing the solar cell substrate 100. The height of the tower base structure is 1 μm, the side length of the top surface is 7 μm, and the side length of the bottom surface is 8 μm.

[0074] The solar cell substrate 100 in the above examples and comparative examples is used to prepare a solar cell. Figure 3 As shown in FIG. 1, the solar cell includes, in sequence, a front surface passivation layer 140, an anti-reflection layer 150, and a front surface electrode 160, which are arranged on the side surface of the solar cell substrate 100 having the tower base structure, and a poly multi-crystalline silicon layer 170, a back surface plating layer 180, and a back surface electrode 190, which are arranged on the other side surface of the solar cell substrate 100. The front surface passivation layer 140 includes, in sequence from the side away from the solar cell substrate 100, a 1 nm thick silicon oxide layer and a 5 nm thick aluminum oxide layer. The anti-reflection layer 150 includes, in sequence from the side away from the solar cell substrate 100, a 50 nm thick silicon nitride layer, a 14 nm thick silicon oxynitride layer, and a 10 nm thick silicon oxide layer. The back surface plating layer 180 includes a 90 nm thick silicon nitride layer.

[0075] The height of the grid line in the front electrode of the solar cell prepared by using the solar cell substrate 100 in Example 1 is 3.85 μm (without the pit depth, i.e. Figure 1 The height of the grid line in the front electrode of the solar cell prepared by using the solar cell substrate 100 in Comparative Example 1 is 5.43 μm, and the width is 26.47 μm.

[0076] The solar cell prepared above is subjected to performance test, and the test method comprises the following steps:

[0077] The performance test uses a halm test sorting device to test the open circuit voltage (Voc), short circuit current (Isc), fill factor (FF), photoelectric conversion efficiency (Eta), etc. The halm machine is a device simulating sunlight, and is further equipped with an electronic load, a data acquisition and calculation device, etc. for testing the electrical performance of the solar cell. The calibration light intensity of the solar cell for control test is 1000±5 W / m 2 , and the test results are shown in Table 1.

[0078] Table 1

[0079]

[0080] By comparing Example 1 and Comparative Example 1, it can be seen that the distance from the first tower base structure 110 protruding surface to the second tower base structure 120 protruding surface in the solar cell substrate 100 is lower, and the plurality of first tower base structures 110 in the grid line coverage area has a relatively flat structure relative to the plurality of second tower base structures 120 in the exposed area. In the process of printing the grid line, the dead angle that the paste cannot contact is reduced, the paste can better contact the solar cell substrate 100, the solar cell can obtain better current, and the photoelectric conversion efficiency of the solar cell is improved.

[0081] The technical features of the above embodiments can be combined in any manner. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present disclosure.

[0082] The above embodiments only express several implementation manners of the present disclosure, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the application. It should be noted that for those skilled in the art, without departing from the concept of the present disclosure, a number of modifications and improvements can be made, which are all within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the appended claims.

Claims

1. A solar cell substrate, characterized by, The surface of the solar cell substrate (100) is provided with a plurality of first tower base structures (110) and a plurality of second tower base structures (120). The surface of the solar cell substrate (100) comprises a grid line covered area and an exposed area, the plurality of first tower base structures (110) are arranged in the grid line covered area, and the plurality of second tower base structures (120) are arranged in the exposed area; the first tower base structure (110) and the second tower base structure (120) away from the top surface of the solar cell substrate (100) respectively protrude from the surface of the solar cell substrate (100), and the distance of the top surface of the first tower base structure (110) protruding from the surface of the solar cell substrate (100) is less than the distance of the top surface of the second tower base structure (120) protruding from the surface of the solar cell substrate (100).

2. The solar cell substrate according to claim 1, wherein In the thickness direction of the solar cell substrate (100), the minimum distance between the first tower base structure (110) and the second tower base structure (120) is 1 μm-2 μm.

3. The solar cell substrate according to claim 1, wherein The height of the first tower base structure (110) is 0.5 μm-1 μm; and / or, The height of the second tower base structure (120) is 0.5 μm-1.5 μm.

4. The solar cell substrate according to claim 1, wherein The area of the top surface of the first tower base structure (110) is greater than the area of the top surface of the second tower base structure (120).

5. The solar cell substrate according to claim 1, wherein The top surface of the first tower base structure (110) is rectangular, and the side length of the top surface is 13 μm-16 μm; and / or, The top surface of the second tower base structure (120) is rectangular, and the side length of the top surface is 5 μm-9 μm.

6. The solar cell substrate of claim 1, wherein The bottom surface of the first tower base structure (110) is rectangular, and the side length of the bottom surface is 13.5 μm-17 μm; and / or, The bottom surface of the second tower base structure (120) is rectangular, and the side length of the bottom surface is 5.5 μm-10 μm.

7. The solar cell substrate according to any one of claims 1 to 6, wherein The solar cell substrate (100) is provided with a plurality of pyramid structures (130) on the side surface away from the first tower base structure (110) and the second tower base structure (120).

8. A solar cell, characterized by The solar cell comprises the solar cell substrate (100) of any one of claims 1-7.

9. The solar cell of claim 8, wherein the first and second doped regions are formed by implanting ions of the same dopant species into the first and second surfaces of the substrate. The solar cell further comprises a grid line, and the grid line covers the grid line covered area in the solar cell substrate (100).

10. The solar cell as described in claim 9, characterized in that, The height of the first tower base structure (110) is less than 0.4 times the height of the grid line; and / or, The top surface of the first tower base structure (110) is rectangular, and the side length of the top surface is 0.4-0.7 times the width of the grid line.

Images