Heterojunction solar cell and photovoltaic module

Abstract

The application provides a heterojunction solar cell and a photovoltaic module. The heterojunction solar cell comprises a heterojunction structure and an electrode structure, the electrode structure comprises a first electrode structure and a second electrode structure, and the first electrode structure and the second electrode structure are respectively arranged on both sides of the heterojunction structure in the thickness direction of the heterojunction structure. At least one of the first electrode structure and the second electrode structure comprises a transparent conductive oxide layer and a grid line, the grid line is embedded in the transparent conductive oxide layer, and the grid line comprises a first grid line and a second grid line, and the width of the second grid line is greater than the width of the first grid line. The application can increase the contact area of the low grid line and the transparent conductive oxide layer, and reduce the contact resistance.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a heterojunction solar cell and photovoltaic module. Background Technology

[0002] With the rapid development of photovoltaic technology, heterojunction solar cells (HJT) are regarded as an important technical route for the next generation of high-efficiency solar cells due to their advantages such as high bifaciality, low degradation rate, low temperature coefficient, and excellent performance in low light.

[0003] In related technologies, heterojunction solar cells typically include a heterojunction structure and transparent conductive thin film layers disposed on both sides of the heterojunction structure, wherein each transparent conductive thin film layer is provided with grid lines.

[0004] However, the current grid lines have a small contact area with the transparent conductive thin film layer, resulting in high contact resistance and reduced current collection capability, thus reducing the performance of heterojunction solar cells. Utility Model Content

[0005] In view of the above problems, embodiments of this application provide a heterojunction solar cell and photovoltaic module that can increase the contact area between the grid lines and the transparent conductive oxide layer and reduce the contact resistance.

[0006] To achieve the above objectives, the embodiments of this application provide the following technical solutions:

[0007] In a first aspect, embodiments of this application provide a heterojunction solar cell, comprising:

[0008] Heterogeneous junction structure;

[0009] An electrode structure, comprising a first electrode structure and a second electrode structure, wherein the first electrode structure and the second electrode structure are respectively disposed on both sides of the heterojunction structure in the thickness direction of the heterojunction structure; wherein at least one of the first electrode structure and the second electrode structure includes:

[0010] Transparent conductive oxide layer;

[0011] The gate line is embedded in the transparent conductive oxide layer, and the gate line includes a first gate line and a second gate line, wherein the width of the second gate line is greater than the width of the first gate line.

[0012] In one possible implementation, the ratio of the width of the second gate line in the second direction to the width of the first gate line in the second direction is greater than 1; wherein the second direction is a direction perpendicular to the extension direction of the first gate line.

[0013] In one possible implementation, the first gate line includes a seed layer and a conductive layer stacked together.

[0014] In one possible implementation, the first gate line extends along a first direction, and the number of second gate lines includes a plurality of second gate lines, which are spaced apart on the first gate line along the first direction.

[0015] In one possible implementation, the length of the second gate line in the first direction is greater than the width of the first gate line in the second direction; the first direction intersects the second direction.

[0016] In one possible implementation, the gate line further includes a third gate line disposed between each of the second gate line and the first gate line, and extending along the thickness direction of the heterojunction structure.

[0017] In one possible implementation, the length of the third gate line in the first direction is less than the length of the second gate line in the first direction;

[0018] And / or, the width of the third gate line in the second direction is equal to the width of the first gate line in the second direction, and less than the width of the second gate line in the second direction.

[0019] In one possible implementation, the number of gate lines includes a plurality of gate lines, which are spaced apart along the second direction.

[0020] In one possible implementation, the transparent conductive oxide layer includes a first transparent conductive oxide layer, a second transparent conductive oxide layer, and a third transparent conductive oxide layer;

[0021] The first transparent conductive oxide layer is disposed on one side of the heterojunction structure in the thickness direction, and the first gate line is disposed on the first transparent conductive oxide layer;

[0022] The second transparent conductive oxide layer is disposed on the side of the first transparent conductive oxide layer opposite to the heterojunction structure, and covers the first gate line;

[0023] The third gate line is disposed within the second transparent conductive oxide layer and is connected to the first gate line;

[0024] The second gate line is disposed on the side of the second transparent conductive oxide layer away from the heterojunction structure, and is opposite to and connected to the third gate line;

[0025] The third transparent conductive oxide layer is disposed on the side of the second transparent conductive oxide layer away from the heterojunction structure and covers the third gate line.

[0026] In one possible implementation, the number of the first gate lines includes a plurality of the first gate lines, which are spaced apart along a second direction, and each of the first gate lines extends along a first direction.

[0027] The second gate line extends along a second direction and spans multiple first gate lines; the first direction and the second direction intersect.

[0028] In one possible implementation, the number of the second gate lines includes a plurality of them, which are spaced apart along the first direction.

[0029] In one possible implementation, the transparent conductive oxide layer includes a first transparent conductive oxide layer, a strip-shaped second transparent conductive oxide layer, and a third transparent conductive oxide layer;

[0030] The first transparent conductive oxide layer is disposed on one side of the heterojunction structure in the thickness direction, and the first gate line is disposed on the side of the first transparent conductive oxide layer opposite to the heterojunction structure.

[0031] A strip-shaped second transparent conductive oxide layer is disposed on the side of the first transparent conductive oxide layer away from the heterojunction structure and extends along the second direction; wherein, the top surface of the second transparent conductive oxide layer is flush with the top surface of the first gate line;

[0032] The second gate line is disposed on the second transparent conductive oxide layer and connected to the first gate line; the second gate line extends along the second direction;

[0033] The third transparent conductive oxide layer is disposed on the first transparent conductive oxide layer and covers the second gate line.

[0034] Secondly, embodiments of this application provide a photovoltaic module, including the heterojunction solar cell described in the first aspect.

[0035] In the heterojunction solar cell and photovoltaic module provided in this application embodiment, the grid lines of at least one of the first electrode structure and the second electrode structure are embedded in the corresponding transparent conductive oxide layer. In this way, the outer peripheral surface of the grid lines is in contact with the transparent conductive oxide layer, which increases the contact area between the grid lines and the transparent conductive oxide layer, reduces the contact resistance between the grid lines and the transparent conductive oxide layer, improves the current collection capability, and thus improves the performance of the heterojunction solar cell. In addition, embedding the grid lines in the corresponding transparent oxide layer can also increase the adhesion of the grid lines and reduce the risk of grid lines falling off.

[0036] Furthermore, the second grid line is also covered by a transparent conductive oxide layer. This prevents the second grid line from being oxidized and eliminates the need for an additional anti-oxidation layer covering it. The dense structure of the transparent conductive oxide layer achieves physical isolation, ensuring long-term stability of the isolation effect. It also reduces the number of electrode fabrication steps and improves the yield of heterojunction solar cells.

[0037] In addition to the technical problems solved by the embodiments of this application, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions described above, other technical problems that can be solved by the heterojunction solar cells and photovoltaic modules provided by the embodiments of this application, other technical features included in the technical solutions, and the beneficial effects brought about by these technical features will be further explained in detail in the specific implementation methods. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 A cross-sectional view of a heterojunction solar cell provided in an embodiment of this application;

[0040] Figure 2 This is a layout diagram of the grid lines of a heterojunction solar cell provided in an embodiment of this application;

[0041] Figure 3 A cross-sectional view of a heterojunction solar cell provided in another embodiment of this application;

[0042] Figure 4 This is a layout diagram of the grid lines of a heterojunction solar cell provided in another embodiment of this application.

[0043] Explanation of reference numerals in the attached figures:

[0044] 100: Heterojunction structure;

[0045] 200: First electrode structure; 210: Transparent conductive oxide layer; 211: First transparent conductive oxide layer; 212: Second transparent conductive oxide layer; 213: Third transparent conductive oxide layer; 220: Gate line; 221: First gate line; 222: Second gate line; 223: Third gate line;

[0046] 300: Second electrode structure. Detailed Implementation

[0047] In related technologies, to reduce the width of the first grid line, the fabrication process of the first grid line is replaced by electroplating copper instead of the traditional screen printing process. However, the above process has the following drawbacks: First, the first grid line is usually placed on a transparent conductive oxide layer, resulting in a small contact area between the bottom of the first grid line and the transparent conductive oxide layer. If the first grid line is made thinner, the contact resistance between the first grid line and the transparent conductive oxide layer will increase, reducing the current collection capability and adversely affecting the efficiency of the cell. Second, copper is prone to oxidation and has insufficient mechanical strength, which will lead to increased resistance and easy breakage of the copper grid line, reducing the performance and yield of heterojunction solar cells.

[0048] To address the aforementioned technical problems, this application provides a heterojunction solar cell and photovoltaic module. At least one of the first and second electrode structures has its grid lines embedded within a corresponding transparent conductive oxide layer. This ensures that the outer periphery of the grid lines is in contact with the transparent conductive oxide layer, increasing the contact area and reducing the contact resistance, thereby improving current collection capability and ultimately enhancing the performance of the heterojunction solar cell. Furthermore, embedding the grid lines within the corresponding transparent oxide layer also increases their adhesion, reducing the risk of grid line detachment. In addition, the second grid line is also covered by the transparent conductive oxide layer, preventing oxidation of the second grid line and eliminating the need for an additional anti-oxidation layer. This dense structure of the transparent conductive oxide layer achieves physical isolation, ensuring long-term stability of the isolation effect. It also reduces the electrode structure fabrication steps and improves the yield of the heterojunction solar cell.

[0049] To make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent and understandable, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0050] This application provides a heterojunction solar cell that can be used in photovoltaic modules.

[0051] Please refer to Figures 1 to 4 The heterojunction solar cell includes a heterojunction structure 100, which may include a substrate, a first intrinsic layer, a first doped layer, a second intrinsic layer, and a second doped layer. The substrate may be a semiconductor substrate; for example, it may include N-type or P-type crystalline silicon, used as a light-absorbing layer.

[0052] Along the thickness direction of the substrate, the substrate includes a first surface and a second surface disposed opposite to each other. A first intrinsic layer and a first doped layer are stacked on the first surface of the substrate, and a second intrinsic layer and a second doped layer are stacked on the second surface of the substrate. The first doped layer has a different conductivity type than the second doped layer. For specific structural details, please refer to relevant technologies; this embodiment will not elaborate further.

[0053] The heterojunction solar cell also includes an electrode structure, wherein the cell structure includes a first electrode structure 200 and a second electrode structure 300. In the thickness direction of the heterojunction structure 100, the first electrode structure 200 and the second electrode structure 300 are respectively disposed on both sides of the heterojunction structure 100.

[0054] Wherein, at least one of the first electrode structure 200 and the second electrode structure 300 includes:

[0055] A transparent conductive oxide layer 210 is disposed on the heterojunction structure 100 to enable electrical conduction between the heterojunction structure 100 and the subsequent gate line 220. The material of the transparent conductive oxide layer 210 includes, but is not limited to, indium tin oxide (ITO).

[0056] The gate line 220 is embedded within the transparent conductive oxide layer 210, meaning it is covered by the layer. The gate line 220 includes a first gate line 221 and a second gate line 222, with the second gate line 222 having a wider width than the first gate line 221. In other words, the first gate line 221 is a thin gate line, and the second gate line 222 is a wider main gate line. Both the first gate line 221 and the second gate line 222 are made of copper.

[0057] The first gate line 221 is used to collect holes or electrons from the heterojunction structure 100, and the collected holes or electrons are led to the solder ribbon through the second gate line 222. Therefore, in order to facilitate the soldering of the solder ribbon and the second gate line 222 and to improve the soldering quality, the width of the second gate line 222 is usually made large.

[0058] It should be noted that at least one of the first electrode structure 200 and the second electrode structure 300 includes the above-mentioned structure, which can be understood as one of the first electrode structure 200 and the second electrode structure 300, or both the first electrode structure 200 and the second electrode structure 300 include the above-mentioned structure.

[0059] In this embodiment, the grid lines 220 of at least one of the first electrode structure 200 and the second electrode structure 300 are embedded in the transparent conductive oxide layer 210. In this way, the outer peripheral surface of the grid lines 220 is in contact with the transparent conductive oxide layer 210, which increases the contact area between the grid lines 220 and the transparent conductive oxide layer 210, reduces the contact resistance between the grid lines 220 and the transparent conductive oxide layer 210, improves the current collection capability, and thus improves the performance of the heterojunction solar cell.

[0060] Furthermore, the second gate line 222 is also covered by a transparent conductive oxide layer 210. This prevents the second gate line 222 from being oxidized and eliminates the need for an additional anti-oxidation layer covering it. The dense structure of the transparent conductive oxide layer 210 achieves physical isolation, ensuring long-term stability of the isolation effect. It also reduces the number of electrode fabrication steps and improves the yield of heterojunction solar cells.

[0061] In some embodiments, the ratio of the width W2 of the second gate line 222 in the second direction to the width W1 of the first gate line 221 in the second direction is greater than 1. For example, the ratio of the width W2 of the second gate line 222 in the second direction to the width W1 of the first gate line 221 in the second direction is greater than or equal to 2 and less than or equal to 5. Here, the second direction is the direction perpendicular to the extending direction of the first gate line 221, i.e. Figure 2 Center Y direction.

[0062] For example, the width W1 of the first gate line 221 in the second direction is 10 μm to 20 μm, and exemplarily, the width of the first gate line 221 in the second direction is 15 μm. The width W2 of the second gate line 222 in the second direction is 60 μm to 70 μm, and exemplarily, the width W2 of the second gate line 222 in the second direction is 65 μm.

[0063] It should be noted that the heights of the first gate line 221 and the second gate line 222 can also be limited in this embodiment. For example, the thickness of the first gate line 221 is 10 μm to 20 μm, or for example, 15 μm. The thickness of the second gate line 222 is 10 μm to 20 μm, or for example, 15 μm. Alternatively, the thicknesses of the first gate line 221 and the second gate line 222 can be the same.

[0064] In this embodiment, the ratio of the width W2 of the second grid line 222 in the second direction to the width W1 of the first grid line 221 in the second direction is greater than or equal to 1. This wider second grid line design significantly increases its contact area with the charge carriers on the battery surface, thereby effectively collecting the charge carriers transmitted from the first grid line and those generated directly in its coverage area, reducing the recombination loss of charge carriers on the battery surface, and thus improving the photoelectric conversion efficiency of the battery.

[0065] While ensuring a certain width ratio, the height of the first grid line 221 and the second grid line 222 are reasonably limited. The appropriate thickness allows the grid lines to have sufficient conductive cross-sectional area, reducing the resistance during current transmission, reducing energy loss caused by resistance, and improving the output power of the battery.

[0066] Compared to screen-printed silver paste in related technologies, the grid lines 220 prepared in this embodiment have a larger aspect ratio to reduce the transmission resistance of the grid lines 220, thereby improving the conversion efficiency of the heterojunction solar cell, as well as increasing the short-circuit current and fill factor of the heterojunction solar cell. At the same time, increasing the aspect ratio of the grid lines can improve conductivity and reduce shading loss.

[0067] However, increasing the aspect ratio of the gate line 220 makes it more prone to detachment. Therefore, in this embodiment, the gate line 220 is embedded in the transparent conductive oxide layer 210, which enhances the adhesion of the gate line and reduces the risk of detachment. It should be noted that the first gate line 221 is not prepared using the traditional electroplating method. In some embodiments, the first gate line 221 includes a seed layer and a conductive layer stacked together, with the conductive layer prepared by electroplating. This seed layer enhances the interfacial bonding between the first gate line 221 and the first transparent conductive oxide layer 211, reducing or even eliminating the risk of detachment. Furthermore, forming the seed layer through physical vapor deposition (PVD) improves the deposition uniformity of the seed layer, enhancing the morphology and electrical stability of the first gate line 221.

[0068] It should be noted that there are multiple options for the layout of the first gate line 221 and the second gate line 222.

[0069] As one possible implementation, please refer to Figure 1 and Figure 2 The first gate line 221 extends along a first direction, and the number of second gate lines 222 includes multiple second gate lines 222, which are arranged at intervals on the first gate line 221 along the first direction. The first direction can be the length direction of the first gate line 221, i.e. Figure 2 In the X direction.

[0070] In this embodiment, the second gate line 222 is used to collect holes or electrons from the heterojunction structure 100 collected by the first gate line 221. Therefore, the second gate line 222 can completely cover the first gate line 221, or it can cover the first gate line 221 at intervals.

[0071] When the number of second grid lines 222 is multiple, making them discontinuous, on the one hand, it helps to improve the stress distribution of the entire grid line, reduce stress concentration problems that may occur due to continuous structures, thereby improving the stability and reliability of the grid line and extending the lifespan of the heterojunction solar cell. On the other hand, the spaced second grid lines 222 can also reduce the amount of metal used, thus lowering the production cost of the second grid lines 222.

[0072] In some embodiments, the length L of the second gate line 222 in the first direction is greater than the width W1 of the first gate line 221 in the second direction. The first direction intersects the second direction. This helps to increase the contact area between the second gate line 222 and the charge carriers in the heterojunction structure 100. The longer second gate line 222 can cover a larger area, more effectively collect holes or electrons transmitted from the first gate line 221, reduce recombination losses of charge carriers during transmission, and improve the collection efficiency of charge carriers.

[0073] Please continue to refer to this. Figure 2 The gate line 220 also includes a third gate line 223, which is disposed between the first gate line 221 and each of the second gate lines 222 and extends along the thickness direction of the heterojunction structure 100. In other words, the number of second gate lines 222 corresponds to the number of third gate lines 223.

[0074] This allows the first gate line 221, the second gate line 222, and the third gate line 223 to form a three-dimensional conductive path. Unlike related technologies where charge carriers need to be transported laterally within the transparent conductive oxide layer 210 to the second gate line 222, this embodiment utilizes the third gate line 223 to provide a vertical channel, reducing series resistance and improving the performance of the heterojunction solar cell.

[0075] In some embodiments, the length of the third gate line 223 in the first direction is less than the length of the second gate line 222 in the first direction; and / or, the width of the third gate line 223 in the second direction is equal to the width of the first gate line 221 in the second direction and less than the width of the second gate line 222 in the second direction.

[0076] With this configuration, the longitudinal cross-sectional shape of the second gate line 222 and the third gate line 223 is a T-shaped structure. In this way, the incident light enters the electrode structure from the corresponding surfaces, is reflected by the first gate line 221, and is reflected again in the region between the second gate line 222 and the third gate line 223 before entering the heterojunction structure 100, thus improving the utilization rate of the incident light.

[0077] In some embodiments, the number of gate lines 220 includes multiple gate lines 220, which are spaced apart along the second direction. This enables the formation of a more extensive and uniform current collection network on the surface of the heterojunction structure. In this embodiment, each gate line 220 has a relatively independent collection area, reducing interference between adjacent gate lines 220, thereby ensuring that charge carriers generated from different locations in the heterojunction structure 100 can be effectively and uniformly collected, improving the overall efficiency and stability of current collection.

[0078] Please continue to refer to this. Figure 1 The transparent conductive oxide layer 210 includes a first transparent conductive oxide layer 211, a second transparent conductive oxide layer 212, and a third transparent conductive oxide layer 213.

[0079] A first transparent conductive oxide layer 211 is disposed on one side of the heterojunction structure 100 in the thickness direction. A first gate line 221 is disposed on the side of the first transparent conductive oxide layer 211 opposite to the heterojunction structure 100. Figure 1 As shown in the diagram, the first gate line 221 is disposed on the top surface of the first transparent conductive oxide layer 211.

[0080] The second transparent conductive oxide layer 212 is disposed on the side of the first transparent conductive oxide layer 211 away from the heterojunction structure 100, and covers the first gate line 221.

[0081] The third gate line 223 is disposed within the second transparent conductive oxide layer 212 and is connected to the first gate line 221.

[0082] The second gate line 222 is disposed on the side of the second transparent conductive oxide layer 212 away from the heterojunction structure 100, and is opposite to and connected to the third gate line 223; that is to say, the second gate line 222 is located directly above the third gate line 223.

[0083] The third transparent conductive oxide layer 213 is disposed on the side of the second transparent conductive oxide layer 212 away from the heterojunction structure 100, and covers the third gate line 223.

[0084] The thicknesses of the first transparent conductive oxide layer 211, the second transparent conductive oxide layer 212, and the third transparent conductive oxide layer 213 can be equal or unequal. For example, the thickness of the first transparent conductive oxide layer 211 is equal to the thickness of the second transparent conductive oxide layer 212, and greater than the thickness of the third transparent conductive oxide layer 213. For instance, the thicknesses of the first and second transparent conductive oxide layers 211 are 30 mm, and the thickness of the third transparent conductive oxide layer 213 is 10 mm.

[0085] In this way, while ensuring that the grid lines 220 are completely embedded in the transparent conductive oxide layer 210, the thickness of the heterojunction solar cell is not excessively increased, which facilitates the development of heterojunction solar cells towards integration.

[0086] The heterojunction solar cell described above can be fabricated using the following methods, for example:

[0087] A heterojunction structure is formed. Exemplarily, a substrate is provided, and the substrate is cleaned and texturized using chemicals. Along the thickness direction of the substrate, the substrate includes a first surface and a second surface disposed opposite to each other. Subsequently, a first intrinsic layer is formed on the first surface of the substrate by plasma-enhanced chemical vapor deposition (PECVD), and then, by adjusting the deposition parameters, a first doped layer is formed on the first intrinsic layer.

[0088] Next, the structure is flipped over, and a first intrinsic layer is formed on the second surface of the substrate using plasma-enhanced chemical vapor deposition (PECVD). Then, the deposition parameters are adjusted to form a second doped layer on the second intrinsic layer. The first doped layer has an N-type conductivity, and the second doped layer has a P-type conductivity.

[0089] The following embodiments all use the same structure for the first electrode structure 200 and the second electrode structure 300, and the above-described structures are used as examples for detailed description.

[0090] Please combine Figure 1 and Figure 2 Subsequently, a first transparent conductive oxide layer 211 of a certain thickness is formed on the first and second surfaces of the heterojunction structure by chemical vapor deposition (PVD). The thickness of the first transparent conductive oxide layer 211 is 30 nm.

[0091] Next, a seed layer is selectively deposited using a PVD process, and then copper gate lines are electroplated on the seed layer to form a first gate line 221. The width and thickness of the first gate line 221 in the second direction are 15 μm. A second transparent conductive oxide layer 212 is then deposited using PVD, with a thickness of 30 nm. The second transparent conductive oxide layer 212 is then patterned to form etched grooves that expose the first gate line 221. The length of the etched grooves in the first direction is 20 μm, the width in the second direction is 15 μm, and the depth of the etched grooves is 30 nm.

[0092] Subsequently, the third gate line 223 is formed in the etched groove through an electroplating process.

[0093] Subsequently, a second gate line 222 is formed by electroplating on the third gate line 223. The second gate line 222 has a width of 65 μm in the second direction, a thickness of 15 μm, and a length of 20 μm in the first direction (slightly larger than the width of the first gate line 221 in the second direction).

[0094] Finally, a third transparent conductive oxide layer 213 with a thickness of 10 nm was deposited using PVD.

[0095] As another possible implementation, please refer to Figure 3 and Figure 4 The first grid line 221 comprises multiple first grid lines 221 arranged at intervals along a second direction, and each first grid line 221 extends along a first direction. A second grid line 222 extends along the second direction and spans across the multiple first grid lines 221; the first and second directions intersect. It should be noted that the dimension of the first grid line 221 in the second direction is the width of the first grid line 221, and the dimension of the second grid line 222 in the first direction is the width of the second grid line 222. In this way, the second grid line 222 forms a bridging structure, allowing light to pass through the area between any adjacent first grid lines 221 and below the second grid line 222. After reflection, the light can enter the battery interior, improving the utilization rate of incident light and thus enhancing battery performance.

[0096] The second grid line 222 comprises two lines, which are arranged at intervals along the first direction. This increases the number of second grid lines 222, thereby improving the battery performance.

[0097] In some embodiments, the transparent conductive oxide layer 210 includes a first transparent conductive oxide layer 211, a strip-shaped second transparent conductive oxide layer 212, and a third transparent conductive oxide layer 213.

[0098] The first transparent conductive oxide layer 211 is disposed on one side of the heterojunction structure 100 in the thickness direction, and the first gate line 221 is disposed on the side of the first transparent conductive oxide layer 211 away from the heterojunction structure 100.

[0099] A strip-shaped second transparent conductive oxide layer 212 is disposed on the side of the first transparent conductive oxide layer 211 opposite to the heterojunction structure 100 and extends along the second direction; wherein the top surface of the second transparent conductive oxide layer 212 is flush with the top surface of the first gate line 221. In other words, the second transparent conductive oxide layer 212 exposes the top surface of the first gate line 221.

[0100] The second gate line 222 is disposed on the side of the second transparent conductive oxide layer 212 away from the heterojunction structure 100 and is connected to the first gate line 221; the second gate line 222 extends along the second direction.

[0101] The third transparent conductive oxide layer 213 is disposed on the side of the first transparent conductive oxide layer 211 away from the heterojunction structure 100, and covers the second gate line 222.

[0102] The thicknesses of the first transparent conductive oxide layer 211, the second transparent conductive oxide layer 212, and the third transparent conductive oxide layer 213 can be equal or unequal. For example, the thickness of the first transparent conductive oxide layer 211 is greater than the thickness of the second transparent conductive oxide layer 212, and the thickness of the third transparent conductive oxide layer 213 is greater than the thickness of the first transparent conductive oxide layer 211. For instance, the thickness of the first transparent conductive oxide layer 211 is 50 nm, the thickness of the second transparent conductive oxide layer 212 is 12 μm, and the thickness of the third transparent conductive oxide layer 213 is 50 mm.

[0103] In this way, while ensuring that the grid lines 220 are completely embedded in the transparent conductive oxide layer 210, the thickness of the heterojunction solar cell is not excessively increased, which facilitates the development of heterojunction solar cells towards integration.

[0104] The heterojunction solar cell described above can be fabricated using the following method, with a detailed description provided using the example of the first electrode structure 200 and the second electrode structure 300 having the same structure.

[0105] For example:

[0106] A heterojunction structure is formed. It should be noted that the steps for forming the heterojunction structure can be referred to the above embodiments, and will not be repeated here.

[0107] Please combine Figure 3 and Figure 4 Subsequently, a first transparent conductive oxide layer 211 of a certain thickness is formed on the first and second surfaces of the heterojunction structure by chemical vapor deposition (PVD). The thickness of the first transparent conductive oxide layer 211 is 50 nm.

[0108] Subsequently, a seed layer is selectively deposited using a PVD process, and then copper gate lines are electroplated on the seed layer to form the first gate line 221. The width of the first gate line 221 in the second direction is 20 μm, and the thickness of the first gate line 221 is 12 μm.

[0109] A strip-shaped second transparent conductive oxide layer 212 with a thickness of 12 μm is deposited again using the PVD method, and the second transparent conductive oxide layer 212 located on top of the first gate line 221 is removed to expose the top surface of the first gate line 221.

[0110] Subsequently, a second gate line 222 is formed in the etched grooves using an electroplating process. The second gate line 222 extends along a second direction and covers the second transparent conductive oxide layer 212, as well as the top surface of the first gate line 221 opposite to the second transparent conductive oxide layer 212. The width of the second gate line 222 in the second direction is 65 μm, and the thickness of the second gate line 222 is 15 μm.

[0111] Finally, a third transparent conductive oxide layer 213 with a thickness of 50 nm was deposited using PVD.

[0112] This application also provides a photovoltaic module, including the heterojunction solar cell described in any of the above embodiments, and therefore possesses all the structure and beneficial effects of a heterojunction solar cell. This embodiment will not be described in detail here.

[0113] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0114] It should be noted that the terms "one embodiment," "embodiment," "exemplary embodiment," "some embodiments," etc., mentioned in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A heterojunction solar cell, characterized in that, include: Heterogeneous junction structure (100); An electrode structure, comprising a first electrode structure (200) and a second electrode structure (300), wherein the first electrode structure (200) and the second electrode structure (300) are respectively disposed on both sides of the heterojunction structure (100) in the thickness direction of the heterojunction structure (100); wherein at least one of the first electrode structure (200) and the second electrode structure (300) includes: Transparent conductive oxide layer (210); A gate line (220) is embedded in the transparent conductive oxide layer (210), and the gate line (220) includes a first gate line (221) and a second gate line (222), and the width of the second gate line (222) is greater than the width of the first gate line (221).

2. The heterojunction solar cell according to claim 1, characterized in that, The ratio of the width of the second gate line (222) in the second direction to the width of the first gate line (221) in the second direction is greater than 1; The second direction is a direction perpendicular to the extension direction of the first gate line (221).

3. The heterojunction solar cell according to claim 1, characterized in that, The first gate line (221) includes a seed layer and a conductive layer stacked together.

4. The heterojunction solar cell according to any one of claims 1-3, characterized in that, The first gate line (221) extends along a first direction, and the number of the second gate lines (222) includes a plurality of them, with the plurality of second gate lines (222) arranged at intervals on the first gate line (221) along the first direction.

5. The heterojunction solar cell according to claim 4, characterized in that, The length of the second gate line (222) in the first direction is greater than the width of the first gate line (221) in the second direction, and the first direction intersects the second direction.

6. The heterojunction solar cell according to claim 5, characterized in that, The gate line (220) further includes a third gate line (223), which is disposed between each of the second gate line (222) and the first gate line (221) and extends along the thickness direction of the heterojunction structure (100).

7. The heterojunction solar cell according to claim 6, characterized in that, The length of the third gate line (223) in the first direction is less than the length of the second gate line (222) in the first direction; And / or, the width of the third gate line (223) in the second direction is equal to the width of the first gate line (221) in the second direction, and less than the width of the second gate line (222) in the second direction.

8. The heterojunction solar cell according to any one of claims 5-7, characterized in that, The number of the gate lines (220) includes a plurality of gate lines (220) arranged at intervals along the second direction.

9. The heterojunction solar cell according to claim 6 or 7, characterized in that, The transparent conductive oxide layer (210) includes a first transparent conductive oxide layer (211), a second transparent conductive oxide layer (212), and a third transparent conductive oxide layer (213); The first transparent conductive oxide layer (211) is disposed on one side of the heterojunction structure (100) in the thickness direction, and the first gate line (221) is disposed on the side of the first transparent conductive oxide layer (211) away from the heterojunction structure (100). The second transparent conductive oxide layer (212) is disposed on the side of the first transparent conductive oxide layer (211) away from the heterojunction structure (100) and covers the first gate line (221); The third gate line (223) is disposed within the second transparent conductive oxide layer (212) and connected to the first gate line (221); The second gate line (222) is disposed on the side of the second transparent conductive oxide layer (212) away from the heterojunction structure (100), and is opposite to and connected to the third gate line (223); The third transparent conductive oxide layer (213) is disposed on the side of the second transparent conductive oxide layer (212) away from the heterojunction structure (100) and covers the third gate line (223).

10. The heterojunction solar cell according to any one of claims 1-3, characterized in that, The number of the first gate lines (221) includes a plurality of them, and the plurality of the first gate lines (221) are arranged at intervals along the second direction, and each of the first gate lines (221) extends along the first direction; The second gate line (222) extends along the second direction and spans a plurality of the first gate lines (221); the first direction and the second direction intersect.

11. The heterojunction solar cell according to claim 10, characterized in that, The number of the second gate lines (222) includes a plurality of them, and the plurality of the second gate lines (222) are arranged at intervals along the first direction.

12. The heterojunction solar cell according to claim 11, characterized in that, The transparent conductive oxide layer (210) includes a first transparent conductive oxide layer (211), a strip-shaped second transparent conductive oxide layer (212), and a third transparent conductive oxide layer (213); The first transparent conductive oxide layer (211) is disposed on one side of the heterojunction structure (100) in the thickness direction; the first gate line (221) is disposed on the side of the first transparent conductive oxide layer (211) away from the heterojunction structure (100); A strip-shaped second transparent conductive oxide layer (212) is disposed on the side of the first transparent conductive oxide layer (211) away from the heterojunction structure (100) and extends along the second direction; wherein, the top surface of the strip-shaped second transparent conductive oxide layer (212) is flush with the top surface of the first gate line (221). The second gate line (222) is disposed on the side of the second transparent conductive oxide layer (212) opposite to the heterojunction structure (100) and is connected to the first gate line (221); the second gate line (222) extends along the second direction; The third transparent conductive oxide layer (213) is disposed on the side of the first transparent conductive oxide layer (211) away from the heterojunction structure (100) and covers the second gate line (222).

13. A photovoltaic module, characterized in that, Including the heterojunction solar cell according to any one of claims 1-12.

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