Solar cell and preparation method and application thereof

Abstract

The invention relates to a solar cell and a preparation method and application thereof. The solar cell comprises a cell main body, a silver seed layer and a metal transmission layer, the silver seed layer has a patterned structure and is arranged on the cell main body, and the silver seed layer and the doped silicon layer in the cell main body form ohmic contact; the material of the metal transmission layer comprises at least one of copper and aluminum; the metal transmission layer is arranged on the battery main body and covers the silver seed layer, and the width of the metal transmission layer is greater than that of the silver seed layer; and the metal transmission layer and the silver seed layer form metal contact. The solar cell provided by the invention can give consideration to relatively low electrode preparation cost and relatively high conversion efficiency.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and particularly to a solar cell, a preparation method thereof, and an application thereof. Background Art

[0002] The metallization process of traditional silicon solar cells usually uses screen printing of silver paste to form electrodes, but the cost of silver paste is high. In traditional processes, attempts have been made to replace silver with base metals such as copper or aluminum to prepare solar cell electrodes, but the following problems still exist: 1. Copper atoms are prone to diffuse into the interior of the silicon wafer to form recombination centers, affecting the efficiency of solar cells; 2. Aluminum is difficult to form a high-quality ohmic contact with silicon, resulting in a high contact resistance and affecting the efficiency of solar cells. Therefore, traditional solar cells are difficult to balance high conversion efficiency and low cost of electrode preparation. Summary of the Invention

[0003] Based on this, it is necessary to provide a solar cell, a preparation method thereof, and an application thereof. The solar cell of this application can balance the low cost of electrode preparation and high conversion efficiency.

[0004] In a first aspect, this application provides a solar cell, including a cell body, a silver seed layer, and a metal transmission layer; the silver seed layer has a patterned structure and is disposed on the cell body, and the silver seed layer and the doped silicon layer in the cell body form an ohmic contact; the material of the metal transmission layer includes at least one of copper and aluminum; the metal transmission layer is disposed on the cell body, the metal transmission layer covers the silver seed layer and the width of the metal transmission layer is greater than the width of the silver seed layer; the metal transmission layer and the silver seed layer form a metal contact.

[0005] In some embodiments, the area of the positive projection of the silver seed layer on the cell body is 20% - 50% of the area of the positive projection of the metal transmission layer on the cell body.

[0006] In some embodiments, the silver seed layer includes a plurality of sub - segments, and each of the sub - segments is arranged in sequence along the length direction of the silver seed layer, and adjacent two sub - segments are in contact or spaced apart.

[0007] In some embodiments, the total length of each of the sub - segments in the silver seed layer is 20% - 100% of the length of the metal transmission layer.

[0008] In some embodiments, the maximum width of each of the sub - segments in the silver seed layer is greater than or equal to 20% of the width of the metal transmission layer.

[0009] In some embodiments, the maximum distance between adjacent two sub - segments is 0.5 mm - 2 mm.

[0010] In some embodiments, the width of the metal transmission layer is 10 µm to 50 µm.

[0011] In some embodiments, the solar cell includes at least one of a PERC solar cell, a TOPCon solar cell, and an HJT solar cell.

[0012] In some embodiments, the cell body includes a substrate having a first surface and a second surface disposed opposite to each other. A first doped silicon layer, a first passivation layer, and a first electrode are sequentially stacked on the first surface. The first electrode includes the silver seed layer and the metal transmission layer, wherein the silver seed layer passes through the first passivation layer and the first doped silicon layer to make contact; A tunneling oxide layer, a second doped silicon layer, a second passivation layer, and a second electrode are sequentially stacked on the second surface. The second electrode includes the silver seed layer and the metal transmission layer. Among them, the silver seed layer passes through the second passivation layer and the second doped silicon layer to make contact; The doping types of the second doped silicon layer and the first doped silicon layer are different.

[0013] In a second aspect, the present application provides a method for manufacturing a solar cell, including the following steps:

[0014] Provide a cell body;

[0015] Prepare a patterned silver seed layer on the cell body to make an ohmic contact between the silver seed layer and the doped silicon layer in the cell body;

[0016] Prepare a metal transmission layer on the cell body, so that the metal transmission layer covers the silver seed layer and the width of the metal transmission layer is greater than the width of the silver seed layer, and make a metal contact between the metal transmission layer and the silver seed layer. The material of the metal transmission layer includes at least one of copper and aluminum.

[0017] In some embodiments, the step of preparing a patterned silver seed layer on the cell body to make an ohmic contact between the silver seed layer and the doped silicon layer in the cell body includes:

[0018] Print a patterned conductive silver paste on the cell body;

[0019] Perform a sintering treatment at 500 °C to 800 °C to make an ohmic contact between the silver seed layer and the doped silicon layer in the cell body.

[0020] In some embodiments, the step of preparing a metal transmission layer on the cell body includes:

[0021] Print a conductive paste on the cell body;

[0022] Annealing and drying are carried out at 200°C to 400°C to form a metal contact between the metal transmission layer and the silver seed layer.

[0023] In a third aspect, the present application provides a photovoltaic module, including the solar cell described in any one of the above or a solar cell prepared by the preparation method of the solar cell described in any one of the above.

[0024] In the above solar cell, an ohmic contact is formed between the silver seed layer and the doped silicon layer in the cell body, so that there is a low contact resistance between the electrode of the solar cell and the doped silicon layer. At the same time, the silver seed layer is covered by a metal transmission layer made of at least one of copper and aluminum. The metal transmission layer and the silver seed layer form a metal contact, and the width of the metal transmission layer is greater than the width of the silver seed layer, so that the carriers collected by the silver seed layer can be transmitted through the metal transmission layer with lower cost. At the same time, the metal transmission layer can have a good metal contact effect with the silver seed layer, so that the overall silver seed layer and the metal transmission layer have a low contact resistance with the cell body. The solar cell of the present application can balance the low preparation cost of the electrode and the high conversion efficiency. Description of the Drawings

[0025] Figure 1 It is a schematic structural diagram of a solar cell provided by an embodiment of the present application;

[0026] Figure 2 It is a schematic diagram of the patterning design of the silver seed layer and the metal transmission layer in Example 1 of the present application;

[0027] Figure 3 It is a schematic diagram of the patterning design of the silver seed layer and the metal transmission layer in Example 2 of the present application;

[0028] Figure 4 It is a schematic diagram of the patterning design of the silver seed layer and the metal transmission layer in Example 3 of the present application;

[0029] Figure 5 It is a schematic diagram of the patterning design of the silver seed layer and the metal transmission layer in Example 4 of the present application;

[0030] Figure 6 It is a schematic diagram of the patterning design of the silver seed layer and the metal transmission layer in Example 5 of the present application;

[0031] Figure 7 It is a schematic diagram of the patterning design of the silver seed layer and the metal transmission layer in Example 6 of the present application;

[0032] Figure 8 It is a schematic diagram of the patterning design of the silver seed layer and the metal transmission layer in Example 7 of the present application;

[0033] Figure 9 Schematic diagram of the patterning design of the silver seed layer and the metal transmission layer in Embodiment 8 of the present application;

[0034] Figure 10 Schematic diagram of the patterning design of the silver seed layer and the metal transmission layer in Embodiment 9 of the present application.

[0035] Description of the reference numerals

[0036] 1 - Substrate; 2 - First doped silicon layer; 3 - First passivation layer; 4 - Silver seed layer; 5 - Metal transmission layer; 6 - First electrode; 7 - Tunneling oxide layer; 8 - Second doped silicon layer; 9 - Second passivation layer; 10 - Second electrode. Detailed implementation manners

[0037] To make the above - mentioned objects, features, and advantages of the present application more obvious and understandable, the following provides a detailed description of the specific implementation manners of the present application. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used in the description of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0039] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of this application, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0041] In this application, unless otherwise clearly specified and defined, terms such as "installed", "connected", "linked", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] Referring to Figure 1 As shown, an embodiment of this application provides a solar cell, including a cell body, a silver seed layer 4, and a metal transport layer 5; the silver seed layer 4 has a patterned structure and is disposed on the cell body, and an ohmic contact is formed between the silver seed layer 4 and the doped silicon layer in the cell body; the material of the metal transport layer 5 includes at least one of copper and aluminum; the metal transport layer 5 is disposed on the cell body, the metal transport layer 5 covers the silver seed layer 4 and the width of the metal transport layer 5 is greater than the width of the silver seed layer 4; a metal contact is formed between the metal transport layer 5 and the silver seed layer 4.

[0043] In the above solar cell, an ohmic contact is formed between the silver seed layer 4 and the doped silicon layer in the cell body, so that there is a low contact resistance between the electrode of the solar cell and the doped silicon layer. At the same time, the silver seed layer 4 is covered by the metal transport layer 5 whose material includes at least one of copper and aluminum, a metal contact is formed between the metal transport layer 5 and the silver seed layer 4, and the width of the metal transport layer 5 is greater than the width of the silver seed layer 4, so that the carriers collected by the silver seed layer 4 can be transported by the metal transport layer 5 with a lower cost. At the same time, the metal transport layer 5 can have a good metal contact effect with the silver seed layer 4, so that the overall silver seed layer 4 and the metal transport layer 5 have a low contact resistance with the cell body. The solar cell of this application can take into account the low preparation cost of the electrode and the high conversion efficiency.

[0044] Furthermore, the solar cell with the above structure can be prepared by a screen printing process without adding extra process steps and equipment, and the operation is simple. Compared with the traditional solar cell with the same structure that directly prepares a silver electrode and the width of the silver electrode is the same as that of the metal conductive layer, in some embodiments of the present application, the solar cell can save more than 40% of the electrode cost and can achieve a loss of the conversion efficiency of the cell less than or equal to 0.06%.

[0045] In some of these embodiments, the metal transport layer 5 is continuous along its length direction.

[0046] The metal transport layer 5 is continuous along its length direction to achieve a better carrier transport effect.

[0047] In some of these embodiments, the orthographic projection area of the silver seed layer 4 on the cell body is 20% - 50% of the orthographic projection area of the metal transport layer 5 on the cell body.

[0048] When the ratio of the orthographic projection area of the silver seed layer 4 on the cell body to the orthographic projection area of the metal transport layer 5 on the cell body is too small, it is likely to cause an excessive overall contact resistance, affecting the conversion efficiency of the solar cell. When the ratio of the orthographic projection area of the silver seed layer 4 on the cell body to the orthographic projection area of the metal transport layer 5 on the cell body is too large, it is likely to cause too high an electrode cost. Within the above range of the ratio of the orthographic projection area of the silver seed layer 4 on the cell body to the orthographic projection area of the metal transport layer 5 on the cell body, it is convenient for the solar cell to balance the relatively low preparation cost of the electrode and the relatively high conversion efficiency. Optionally, the orthographic projection area of the silver seed layer 4 on the cell body is 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48% or 50% of the orthographic projection area of the metal transport layer 5 on the cell body, or the ratio of the orthographic projection area of the silver seed layer 4 on the cell body to the orthographic projection area of the metal transport layer 5 on the cell body can also be within the range between any two of the above percentages.

[0049] In some of these embodiments, the silver seed layer 4 includes a plurality of sub - segments, and the sub - segments are arranged in sequence along the length direction of the silver seed layer 4, and adjacent two sub - segments are in contact or spaced apart.

[0050] It can be understood that adjacent two sub - segments being in contact or spaced apart means that all sub - segments can be spaced apart, or all sub - segments can be in contact, or some sub - segments are in contact and some sub - segments are spaced apart. If all sub - segments are in contact, the silver seed layer 4 is continuous along its length direction. Regardless of how the sub - segments are arranged, the metal transport layer 5 is continuous along its length direction and covers the silver seed layer 4 as a whole.

[0051] In some of these embodiments, the total length of each sub-segment in the silver seed layer 4 is 20% to 100% of the length of the metal transmission layer 5.

[0052] It can be understood that the total length of each sub-segment in the silver seed layer 4 refers to the sum of the lengths of all sub-segments along the length direction of the silver seed layer 4. If the total length of each sub-segment in the silver seed layer 4 is 100% of the length of the metal transmission layer 5, then each sub-segment is in contact setting and the length of the silver seed layer 4 is the same as the length of the metal transmission layer. Within the range of the ratio of the total length of each sub-segment in the silver seed layer 4 to the length of the metal transmission layer 5, it is convenient for the solar cell to take into account the relatively low preparation cost of the electrode and the relatively high conversion efficiency. Optionally, the total length of each sub-segment in the silver seed layer 4 is 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100% of the length of the metal transmission layer 5. Or, the ratio of the total length of each sub-segment in the silver seed layer 4 to the length of the metal transmission layer 5 can also be within the range between any two of the above percentages.

[0053] In some of these embodiments, the maximum width of each sub-segment in the silver seed layer 4 is greater than or equal to 20% of the width of the metal transmission layer 5.

[0054] In some of these embodiments, the maximum width of each sub-segment in the silver seed layer 4 is greater than or equal to 20% of the width of the metal transmission layer 5 and less than or equal to the width of the metal transmission layer 5.

[0055] When the maximum width of each sub-segment in the silver seed layer 4 is too small, it is easy to cause the overall contact resistance to be too large, affecting the conversion efficiency of the solar cell. Within the range of the ratio of the maximum width of each sub-segment in the silver seed layer 4 to the width of the metal transmission layer 5, it is convenient for the solar cell to take into account the relatively low preparation cost of the electrode and the relatively high conversion efficiency. Optionally, the ratio of the maximum width of each sub-segment in the silver seed layer 4 to the width of the metal transmission layer 5 is 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100%. Or, the ratio of the maximum width of each sub-segment in the silver seed layer 4 to the width of the metal transmission layer 5 can also be within the range between any two of the above ratios.

[0056] In some of these embodiments, the maximum distance between two adjacent sub-segments is 0.5 mm to 2 mm.

[0057] Within the range of the maximum distance between two adjacent sub-segments above, it is convenient for the solar cell to take into account both the lower preparation cost of the electrode and the higher conversion efficiency. When the maximum distance between two adjacent sub-segments is too large, it may affect the local carrier transport. Optionally, the maximum distance between two adjacent sub-segments is 0.5 mm, 0.75 mm, 1 mm, 1.25 mm, 1.5 mm, 1.75 mm or 2 mm, or the maximum distance between two adjacent sub-segments can also be within the range between any two of the above distances.

[0058] In some embodiments, the width of the metal transport layer 5 is 10 µm to 50 µm.

[0059] Within the range of the width of the metal transport layer 5 above, it is convenient for the solar cell to take into account both the lower preparation cost of the electrode and the higher conversion efficiency. When the width of the metal transport layer 5 is too small, the transport will be affected. When the width of the metal transport layer 5 is too large, the shielding area for the battery body is too large. Optionally, the width of the metal transport layer 5 is 10 µm, 15 µm, 20 µm, 25 µm, 30 µm, 35 µm, 40 µm, 45 µm or 50 µm, or the width of the metal transport layer 5 can also be within the range between any two of the above widths.

[0060] In some embodiments, the solar cell includes at least one of a PERC solar cell, a TOPCon solar cell, and an HJT solar cell.

[0061] In some embodiments, the battery body includes a substrate 1, the substrate 1 has a first surface and a second surface disposed opposite to each other, a first doped silicon layer 2, a first passivation layer 3, and a first electrode 6 are sequentially stacked on the first surface, the first electrode 6 includes a silver seed layer 4 and a metal transport layer 5, wherein the silver seed layer 4 passes through the first passivation layer 3 and the first doped silicon layer 2 to contact; a tunneling oxide layer 7, a second doped silicon layer 8, a second passivation layer 9, and a second electrode 10 are sequentially stacked on the second surface, the second electrode 10 includes a silver seed layer 4 and a metal transport layer 5, wherein the silver seed layer 4 passes through the second passivation layer 9 and the second doped silicon layer 8 to contact; the doping types of the second doped silicon layer 8 and the first doped silicon layer 2 are different.

[0062] Another embodiment of the present application provides a method for manufacturing a solar cell, including the following steps:

[0063] Provide a battery body;

[0064] Prepare a patterned silver seed layer 4 on the battery body, so that the silver seed layer 4 forms an ohmic contact with the doped silicon layer in the battery body;

[0065] A metal transfer layer 5 is prepared on the battery body, such that the metal transfer layer 5 covers the silver seed layer 4 and the width of the metal transfer layer 5 is greater than the width of the silver seed layer 4, so that the metal transfer layer 5 and the silver seed layer 4 form a metal contact. The material of the metal transfer layer 5 includes at least one of copper and aluminum.

[0066] In some embodiments, the step of preparing the silver seed layer 4 with a patterned structure on the battery body and making the silver seed layer 4 and the doped silicon layer in the battery body form an ohmic contact includes:

[0067] Print a patterned conductive silver paste on the battery body;

[0068] Perform a sintering treatment at 500 °C to 800 °C, so that the silver seed layer 4 and the doped silicon layer in the battery body form an ohmic contact.

[0069] In some embodiments, the step of preparing the metal transfer layer 5 on the battery body includes:

[0070] Print a conductive paste on the battery body;

[0071] Perform annealing and drying at 200 °C to 400 °C, so that the metal transfer layer 5 and the silver seed layer 4 form a metal contact.

[0072] Optionally, the temperature of the sintering treatment is 500 °C, 550 °C, 600 °C, 650 °C, 700 °C, 750 °C or 800 °C, or alternatively, the temperature of the sintering treatment can also be within the range between any two of the above temperatures.

[0073] Optionally, the temperature of the annealing and drying is 200 °C, 220 °C, 240 °C, 260 °C, 280 °C, 300 °C, 320 °C, 340 °C, 360 °C, 380 °C or 400 °C, or alternatively, the temperature of the annealing and drying can also be within the range between any two of the above temperatures.

[0074] Another embodiment of the present application provides a photovoltaic module, including the solar cell of any one of the above or the solar cell prepared by the preparation method of the solar cell of any one of the above.

[0075] The following are specific examples

[0076] Example 1

[0077] Preparation of the solar cell:

[0078] (1) Provide a silicon substrate 1 with a pyramidal texture on the surface;

[0079] (2) Boron diffusion: Prepare a P-type doped silicon layer on the first surface of the silicon substrate 1 by boron diffusion;

[0080] (3)Backside etching: Clean the circumferential plating on the silicon substrate 1 and polish the backside;

[0081] (4)Backside deposition: Sequentially prepare a tunneling oxide layer 7 and an N-type doped silicon layer on the second surface of the silicon substrate 1;

[0082] (5)Prepare the passivation layer: Sequentially deposit an aluminum oxide layer + a silicon nitride layer on the surface of the P-type doped silicon layer as the first passivation layer 3, and sequentially deposit an aluminum oxide layer + a silicon nitride layer on the surface of the N-type doped silicon layer as the second passivation layer 9;

[0083] (6)Electrode preparation: Use screen printing to print conductive silver paste on the first passivation layer 3 and the second passivation layer 9 respectively and perform sintering treatment at 600 °C to form ohmic contacts between the silver seed layer 4 and the N-type doped silicon layer and the P-type doped silicon layer respectively. Use screen printing to print conductive copper paste on the first passivation layer 3 and the second passivation layer 9 respectively and perform annealing treatment at 300 °C to form metal contacts between the metal transmission layer 5 and the silver seed layer 4.

[0084] In the solar cell of Example 1, the pattern designs of the silver seed layer 4 and the metal transmission layer 5 are as Figure 2 shown, wherein, the silver seed layer 4 includes a plurality of parallelogram-shaped sub-segments, each sub-segment is in contact with each other, and the ratio of the total area of the silver seed layer 4 to the area of the metal transmission layer 5 is 36.7%.

[0085] Example 2

[0086] The preparation method of the solar cell in Example 2 is basically the same as that in Example 1, the only difference is that in the solar cell of Example 2, the pattern designs of the silver seed layer 4 and the metal transmission layer 5 are as Figure 3 shown, wherein, the silver seed layer 4 includes a plurality of diamond-shaped sub-segments, each sub-segment is spaced apart from each other, and the ratio of the total area of the silver seed layer 4 to the area of the metal transmission layer 5 is 23.3%.

[0087] Example 3

[0088] The preparation method of the solar cell in Example 3 is basically the same as that in Example 1, the only difference is that in the solar cell of Example 3, the pattern designs of the silver seed layer 4 and the metal transmission layer 5 are as Figure 4 shown, wherein, the silver seed layer 4 includes a plurality of diamond-shaped sub-segments, each sub-segment is in contact with each other, and the ratio of the total area of the silver seed layer 4 to the area of the metal transmission layer 5 is 28.3%.

[0089] Example 4

[0090] The preparation method of the solar cell in Example 4 is basically the same as that in Example 1, the only difference is that in the solar cell of Example 4, the pattern designs of the silver seed layer 4 and the metal transmission layer 5 are asFigure 5 As shown, the silver seed layer 4 includes a plurality of square sub - segments, which are spaced apart from each other. The ratio of the total area of the silver seed layer 4 to the area of the metal transmission layer 5 is 25%.

[0091] Example 5

[0092] The preparation method of the solar cell in Example 5 is basically the same as that in Example 1, except that in the solar cell of Example 5, the pattern designs of the silver seed layer 4 and the metal transmission layer 5 are as Figure 6 shown, where the silver seed layer 4 includes a plurality of square sub - segments, which are in contact with each other. The ratio of the total area of the silver seed layer 4 to the area of the metal transmission layer 5 is 29.3%.

[0093] Example 6

[0094] The preparation method of the solar cell in Example 6 is basically the same as that in Example 1, except that in the solar cell of Example 6, the pattern designs of the silver seed layer 4 and the metal transmission layer 5 are as Figure 7 shown, where the silver seed layer 4 includes a plurality of circular sub - segments, which are spaced apart from each other. The ratio of the total area of the silver seed layer 4 to the area of the metal transmission layer 5 is 22.7%.

[0095] Example 7

[0096] The preparation method of the solar cell in Example 7 is basically the same as that in Example 1, except that in the solar cell of Example 7, the pattern designs of the silver seed layer 4 and the metal transmission layer 5 are as Figure 8 shown, where the silver seed layer 4 includes a plurality of square sub - segments, which are in contact with each other. The ratio of the total area of the silver seed layer 4 to the area of the metal transmission layer 5 is 27.7%.

[0097] Example 8

[0098] The preparation method of the solar cell in Example 8 is basically the same as that in Example 1, except that in the solar cell of Example 8, the pattern designs of the silver seed layer 4 and the metal transmission layer 5 are as Figure 9 shown, where the silver seed layer 4 includes a plurality of oval sub - segments. Every two sub - segments form a group, and the two sub - segments within each group are in contact with each other, and the groups are spaced apart from each other. The ratio of the total area of the silver seed layer 4 to the area of the metal transmission layer 5 is 26.5%.

[0099] Example 9

[0100] The preparation method of the solar cell in Example 9 is basically the same as that in Example 1, except that in the solar cell of Example 9, the pattern designs of the silver seed layer 4 and the metal transmission layer 5 are as Figure 10As shown, the silver seed layer 4 includes a plurality of oval sub-segments, and each sub-segment is in contact with each other. The ratio of the total area of the silver seed layer 4 to the area of the metal transmission layer 5 is 31.7%.

[0101] Comparative Example 1

[0102] The preparation method of the solar cell in Comparative Example 1 is basically the same as that in Example 1, and the only difference is: (6) Electrode preparation: Conductive paste is printed on the first passivation layer 3 and the second passivation layer 9 by screen printing and sintered at 600 °C to form ohmic contacts between the silver electrodes and the N-type doped silicon layer and the P-type doped silicon layer respectively.

[0103] And the size of the silver electrode in Comparative Example 1 is the same as that of the metal transmission layer 5 in Example 1.

[0104] The test results of the solar cells in Examples 1 to 9 and Comparative Example 1 and the reduction ratio of the electrode cost of the solar cells in Examples 1 to 9 compared to the electrode cost of the solar cell in Comparative Example 1 are shown in the following table:

[0105]

[0106] It can be seen from the above test results that the solar cells in Examples 1 to 9 achieve a reduction ratio of electrode cost of 43% to 68% compared to Comparative Example 1 through the silver seed layer 4 and the metal transmission layer 5 in this application. At the same time, the reduction in efficiency of the solar cells in Examples 1 to 9 compared to the solar cell in Comparative Example 1 is less than or equal to 0.06%. That is, the solar cell of this application can balance the relatively low preparation cost of the electrode and the relatively high conversion efficiency.

[0107] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as within the scope described in this specification.

[0108] The above-described embodiments only represent several implementation manners of this application. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several deformations and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this application patent should be subject to the appended claims, and the description and drawings can be used to explain the content of the claims.

Claims

1. A solar cell, characterized in that, It includes a battery body, a silver seed layer, and a metal transmission layer; the silver seed layer has a patterned structure and is disposed on the battery body, and an ohmic contact is formed between the silver seed layer and the doped silicon layer in the battery body; the material of the metal transmission layer includes at least one of copper and aluminum; the metal transmission layer is disposed on the battery body, the metal transmission layer covers the silver seed layer and the width of the metal transmission layer is greater than the width of the silver seed layer; a metal contact is formed between the metal transmission layer and the silver seed layer.

2. The solar cell according to claim 1, wherein The orthographic projection area of the silver seed layer on the battery body is 20% - 50% of the orthographic projection area of the metal transmission layer on the battery body.

3. The solar cell according to claim 1, characterized in that, The silver seed layer includes a plurality of sub - segments, and each of the sub - segments is arranged in sequence along the length direction of the silver seed layer, and adjacent two sub - segments are in contact and / or spaced apart.

4. The solar cell according to claim 3, characterized in that, The total length of each of the sub - segments in the silver seed layer is 20% - 100% of the length of the metal transmission layer; and / or, The maximum width of each of the sub - segments in the silver seed layer is greater than or equal to 20% of the width of the metal transmission layer.

5. The solar cell according to claim 3, characterized in that, The maximum distance between adjacent two sub - segments is 0.5 mm - 2 mm; and / or, The width of the metal transmission layer is 10 µm - 50 µm.

6. The solar cell according to any one of claims 1 to 5, characterized in that, The solar cell includes at least one of a PERC solar cell, a TOPCon solar cell, and an HJT solar cell.

7. The solar cell according to any one of claims 1 to 5, characterized in that The battery body includes a substrate, the substrate has a first surface and a second surface which are oppositely arranged, a first doped silicon layer, a first passivation layer, and a first electrode are sequentially stacked on the first surface, the first electrode includes the silver seed layer and the metal transmission layer, wherein the silver seed layer passes through the first passivation layer and contacts the first doped silicon layer; A tunneling oxide layer, a second doped silicon layer, a second passivation layer, and a second electrode are sequentially stacked on the second surface, the second electrode includes the silver seed layer and the metal transmission layer, wherein the silver seed layer passes through the second passivation layer and contacts the second doped silicon layer; the doping types of the second doped silicon layer and the first doped silicon layer are different.

8. A method for preparing a solar cell, characterized in that, It includes the following steps: Provide a battery body; Prepare a silver seed layer with a patterned structure on the battery body to form an ohmic contact between the silver seed layer and the doped silicon layer in the battery body; Prepare a metal transmission layer on the battery body, make the metal transmission layer cover the silver seed layer and the width of the metal transmission layer is greater than the width of the silver seed layer, make a metal contact between the metal transmission layer and the silver seed layer, and the material of the metal transmission layer includes at least one of copper and aluminum.

9. The method for preparing a solar cell according to claim 8, wherein The step of preparing a silver seed layer with a patterned structure on the battery body to form an ohmic contact between the silver seed layer and the doped silicon layer in the battery body includes: Print a patterned conductive silver paste on the battery body; Perform a sintering treatment at 500 °C - 800 °C to form an ohmic contact between the silver seed layer and the doped silicon layer in the battery body; and / or, The step of preparing a metal transmission layer on the battery body includes: Print a conductive paste on the battery body; Anneal and dry at 200°C to 400°C to form a metal contact between the metal transfer layer and the silver seed layer.

10. A photovoltaic module, characterized in that, Comprising the solar cell according to any one of claims 1 to 7 or the solar cell prepared by the preparation method of the solar cell according to any one of claims 8 to 9.

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