A back contact solar cell, a solar cell module, and a photovoltaic system

Abstract

This utility model discloses a back-contact solar cell, a solar cell module, and a photovoltaic system. The back-contact solar cell includes multiple electrode structures; each electrode structure includes a main electrode structure and multiple sub-electrode structures; the main electrode structure includes a first main grid extending along a first direction; each sub-electrode structure includes multiple first sub-grids extending along a second direction and second sub-grids extending along the first direction; the first direction and the second direction intersect; a second sub-grid is connected between two adjacent first sub-grids, and the connection point between the second sub-grid and the first sub-grid is located between the two ends of the first sub-grid. By setting the connection point between the second sub-grid and the first sub-grid to be located at the two ends of the first sub-grid, it is beneficial to shorten the carrier transport path between the second sub-grid and the first main grid, thereby improving the current collection efficiency.

Description

Technical Field

[0001] This utility model relates to the field of solar cell technology, and in particular to a back-contact solar cell, solar cell module and photovoltaic system. Background Technology

[0002] Back-contact solar cells combine the superior tunneling oxide / doped polycrystalline silicon passivation contact technology of mainstream TOPCon solar cells with the contact characteristics of the back electrode. They represent the next generation of mainstream crystalline silicon solar cells and have features such as high efficiency and aesthetic appeal.

[0003] Although back-contact solar cells have significant advantages in efficiency conversion, their interdigitated back-contact structure, with all electrodes located on the back of the cell, results in a longer carrier transport path at the cell's edge and a decrease in current collection rate. This issue has always been a key challenge restricting the performance and reliability of TBC cells. Utility Model Content

[0004] This invention provides a back-contact solar cell, a solar cell module, and a photovoltaic system to solve the problem of long carrier transport paths and low current collection efficiency in the edge region of existing back-contact solar cells.

[0005] In a first aspect, the present invention provides a back-contact solar cell, comprising multiple electrode structures;

[0006] The electrode structure includes a main electrode structure and multiple sub-electrode structures;

[0007] The main electrode structure includes a first main gate extending along a first direction; the secondary electrode structure includes a plurality of first secondary gates extending along a second direction and a second secondary gate extending along the first direction; the first direction intersects the second direction;

[0008] There exists a second sub-gate connected between two adjacent first sub-gates, and the connection point between the second sub-gate and the first sub-gate is located between the two ends of the first sub-gate.

[0009] Optionally, the width of the second sub-gate in the second direction is greater than the width of the first sub-gate in the first direction.

[0010] Optionally, the width W2 of the second sub-gate in the second direction and the width W1 of the first sub-gate in the first direction satisfy: W2 ≥ 1.5 × W1.

[0011] Optionally, the main electrode structure further includes a second main gate extending along the first direction and a third main gate extending along the second direction;

[0012] The third main gate is connected between the first main gate and the second main gate.

[0013] Optionally, the secondary electrode structure further includes a third secondary gate extending along the second direction;

[0014] The third sub-gate is connected between the first main gate and the second main gate.

[0015] Optionally, the third sub-gate extends through the second main gate along the second direction.

[0016] Optionally, the plurality of electrode structures include at least one first electrode structure and at least one second electrode structure; the main electrode structure includes a first main electrode structure and a second main electrode structure; the sub-electrode structure includes a first sub-electrode structure and a second sub-electrode structure; the first main gate includes a first A main gate and a first B main gate; the first sub-gate includes a first A sub-gate and a first B sub-gate; the second sub-gate includes a second A sub-gate and a second B sub-gate;

[0017] The first electrode structure includes a first main electrode structure and a plurality of first sub-electrode structures; the first main electrode structure includes a first A main gate extending along the first direction; the first sub-electrode structure includes a plurality of first A sub-gates extending along the second direction and a second A sub-gate extending along the first direction.

[0018] The second electrode structure includes a second main electrode structure and a plurality of second sub-electrode structures; the second main electrode structure includes a first B main gate extending along the first direction; the second sub-electrode structure includes a plurality of first B sub-gates extending along the second direction and a second B sub-gate extending along the first direction.

[0019] The first main gate A and the first main gate B are arranged along the second direction;

[0020] The first sub-gate A and the first sub-gate B are arranged alternately along the first direction.

[0021] Optionally, along the second direction, the distance d1 between the first main gate A and the first secondary gate B satisfies: d1 ≥ 0.5 mm;

[0022] Along the second direction, the distance d2 between the first main gate B and the first auxiliary gate A satisfies: d2≥0.5mm.

[0023] Secondly, embodiments of the present invention provide a solar cell module, including a back-contact solar cell as described in the first aspect.

[0024] Thirdly, embodiments of the present invention provide a photovoltaic system including a solar cell module as described in the second aspect.

[0025] The technical solution of this utility model embodiment, by setting the connection point between the second sub-gate and the first sub-gate at both ends of the first sub-gate, is beneficial to shorten the carrier transport path between the second sub-gate and the first main gate, thereby improving the current collection rate.

[0026] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of a back-contact solar cell provided for the prior art;

[0029] Figure 2 A schematic diagram of the structure of a back-contact solar cell provided in an embodiment of this utility model;

[0030] Figure 3 A schematic diagram of another back-contact solar cell provided in this embodiment of the present invention;

[0031] Figure 4 A schematic diagram of another back-contact solar cell provided in this embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of a solar cell module provided in an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of a photovoltaic system provided in an embodiment of the present invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices. The terms "upper," "lower," "left," "right," etc., indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings and are only used to describe the relative positional relationships between components or constituent parts, and do not specifically limit the specific installation orientation of each component or constituent part.

[0036] Figure 1 A schematic diagram of a back-contact solar cell provided for reference in the prior art. Figure 1 In the prior art, a back-contact solar cell 200 includes at least one positive electrode structure 20A and at least one negative electrode structure 20B. The positive electrode structure 20A includes a positive main grid 21A and a plurality of positive and sub-grids 22A connected together. Figure 1 Taking the four rows of positive and negative gates 22A as an example, the positive and negative gates 22A correspond to the P-type doped region, which can collect holes (positive charges) and transfer the collected holes to the positive main gate 21A. The negative electrode structure 20B includes the negative main gate 21B and the negative sub-gate 22B connected together. Figure 1 Taking the 4-row negative sub-gate 22B as an example, the negative sub-gate 22B corresponds to the N-type doped region, which can collect electrons (negative charges) and transfer the collected electrons to the negative main gate 21B. The positive sub-gate 22A and the negative sub-gate 22B are arranged alternately in an interdigitated pattern.

[0037] To ensure that the charge carriers (i.e. electrons) at the negative sub-gate 22B that are partially disconnected from the positive main gate 21A can be transferred to the negative main gate 21B, a third negative sub-gate 22B is set between two adjacent negative sub-gates 22B to connect the two negative sub-gates 22B. The three negative sub-gates 22B ultimately form a "hook"-shaped structure so that the charge carriers (electrons) collected by the negative sub-gates 22B that are partially disconnected from the positive main gate 21A and cannot be connected to the negative main gate 21B in the two adjacent negative sub-gates 22B can be transferred to the negative main gate 21B through the other negative sub-gate 22B that is connected to the negative main gate 21B. To ensure that the charge carriers (i.e., holes) at the positive and negative gates 22A that are partially disconnected by the negative gate 21B can be transferred to the positive gate 21A, a positive and negative gate 22A connecting the two positive and negative gates 22A will be set between the two adjacent positive and negative gates 22A. The three positive and negative gates 22A will eventually form a "hook"-shaped structure so that the charge carriers (electrons) collected by the positive and negative gates 22A that are partially disconnected by the negative gate 21B and cannot be connected to the positive gate 21A in the two adjacent positive and negative gates 22A will be transferred to the positive gate 21A through the other positive and negative gate 22A that is connected to the positive gate 21A.

[0038] Although the above-mentioned "hook" shaped positive and negative gates 22A and 22B solve the problem of carrier transport at the secondary gate that is partially disconnected by the main gate, the carrier transport distance is relatively long. The recombination loss in the long-distance carrier transport process will cause a decrease in short-circuit current and increase series resistance, resulting in fill factor loss.

[0039] Figure 2 This is a schematic diagram of a back-contact solar cell provided in an embodiment of the present invention, with reference to... Figure 2 The back-contact solar cell 100 in this embodiment of the invention includes multiple electrode structures 10. Each electrode structure 10 includes a main electrode structure 11 and multiple sub-electrode structures 12. The main electrode structure 11 includes a first main grid 111 extending along a first direction Y. Each sub-electrode structure 12 includes multiple first sub-grids 121 extending along a second direction X and second sub-grids 122 extending along the first direction Y. The first direction Y intersects the second direction X. A second sub-grid 122 is present between two adjacent first sub-grids 121, and the connection point between the second sub-grid 122 and the first sub-grid 121 is located between the two ends of the first sub-grid 121.

[0040] For example, the first direction Y and the second direction X can be perpendicular to each other. The first main gate 111 and the first sub-gate 121 in the same electrode structure 10 are connected together. The first main gate 111, the first sub-gate 121 in different electrode structures 10 are not connected together, and are isolated from each other. The first sub-gate 121 in the same electrode structure 10 can transfer the collected charge carriers (holes or electrons) to the first main gate 111. To address the issue of long carrier transmission distances in the "hook"-shaped positive and negative sub-gates 22A and 22B, a second sub-gate 122 is provided between the first sub-gate 121 separated by a portion of the first main gate 111 and the adjacent first sub-gate 121, as described in this embodiment of the invention. Unlike existing technologies, the connection points between the second sub-gate 122 and the two first sub-gates 121 are all located between the two ends of the two first sub-gates 121, forming an "I"-shaped structure. This structure helps to reduce the problem of long carrier transmission distances at the first sub-gate 121 that is partially disconnected by the first main gate 111.

[0041] For details, please refer to [link / reference]. Figure 2 The plurality of electrode structures 10 include at least one first electrode structure 10A and at least one second electrode structure 10B. The main electrode structure 11 includes a first main electrode structure 11A and a second main electrode structure 11B. The sub-electrode structure 12 includes a first sub-electrode structure 12A and a second sub-electrode structure 12B. The first main gate 111 includes a first A main gate 111A and a first B main gate 111B. The first sub-gate 121 includes a first A sub-gate 121A and a first B sub-gate 121B. The second sub-gate 122 includes a second A sub-gate 122A and a second B sub-gate 122B. The first electrode structure 10A includes a first main electrode structure 11A and a plurality of first sub-electrode structures 12A. The first main electrode structure 11A includes a first A main gate 111A extending along a first direction Y. The first sub-electrode structure 12A includes a plurality of first A sub-gates 121A extending along a second direction X and a second A sub-gate 122A extending along the first direction Y. The second electrode structure 10B includes a second main electrode structure 11B and a plurality of second sub-electrode structures 12B. The second main electrode structure 11B includes a first secondary main gate 111B extending along a first direction Y. The second sub-electrode structure 12B includes a plurality of first secondary sub-gates 121B extending along a second direction X and a second secondary sub-gate 122B extending along the first direction Y. The first primary main gate 111A and the first secondary main gate 111B are arranged along the second direction X. The first secondary sub-gates 121A and the first secondary sub-gates 121B are arranged alternately along the first direction Y.

[0042] For example, a second secondary gate 122B is provided between a first secondary gate 121B separated by a portion of the first primary gate 111A and an adjacent first secondary gate 121B. The connection points of the second secondary gate 122B with the two first secondary gates 121B are all located between the two ends of the two first secondary gates 121B, forming an "I"-shaped structure. This helps to reduce the problem of long carrier transmission distance at the first secondary gate 121B that is partially disconnected by the first primary gate 111A. Similarly, a second secondary gate 122A is provided between a first secondary gate 121A separated by a portion of the first primary gate 111B and an adjacent first secondary gate 121A. The connection points of the second secondary gate 122A with the two first secondary gates 121A are all located between the two ends of the two first secondary gates 121A, forming an "I"-shaped structure. This helps to reduce the problem of long carrier transmission distance at the first secondary gate 121A that is partially disconnected by the first secondary gate 111B.

[0043] It should be noted that, in one feasible embodiment, the first electrode structure 10A can be a positive electrode structure for collecting and transporting hole carriers, and the second electrode structure 10B can be a negative electrode structure for collecting and transporting electron carriers. In another feasible embodiment, the first electrode structure 10A can be a negative electrode structure for collecting and transporting electron carriers, and the second electrode structure 10B can be a positive electrode structure for collecting and transporting hole carriers. This utility model embodiment does not limit this.

[0044] Preferably, the connection point between the second sub-gate 122 and the first sub-gate 121, which is partially disconnected by the first main gate 111, is located at the midpoint of the first sub-gate 121. In this case, the carrier transmission distances at both ends of the shorter disconnected first sub-gate 121 will be shorter. Specifically, the connection point between the second sub-gate 122A and the first sub-gate 121A, which is partially disconnected by the first main gate 111B, is located at the midpoint of the first sub-gate 121A, and the connection point between the second sub-gate 122B and the first sub-gate 121B, which is partially disconnected by the first main gate 111A, is located at the midpoint of the first sub-gate 121B.

[0045] It should be noted that the main grid in the main electrode structure 11 of this utility model is usually made of non-burn-through slurry; the secondary grid in the secondary electrode structure 12 of this utility model is usually made of burn-through slurry.

[0046] To each Figure 1 The back-contact solar cell 200 shown and Figure 2 The back-contact solar cell 100 shown was subjected to IV testing, and the electrical performance data shown in Table 1 below were obtained:

[0047] Table 1

[0048]

[0049] It should be noted that, Figure 1 The back-contact solar cell 200 shown and Figure 2 The back-contact solar cells 100 shown are identical in manufacturing process except for the sub-grid structures, which are either "hook"-shaped or "I"-shaped. Both involve laser etching followed by printing. The laser energy and wet weight used are the same, and there are no printing defects on the screen. To minimize experimental error and ensure accuracy, 400 cells were taken before laser etching and divided into two groups of 200 cells each for verification. This verification was repeated three times while maintaining the same experimental conditions. In Table 1, Eta represents the conversion efficiency, Uoc represents the open-circuit voltage, Isc represents the short-circuit current, FF represents the fill factor, Rser represents the series resistance, Rshunt represents the parallel resistance, and Irev represents the reverse current. Table 1 shows that the efficiency of the back-contact solar cell 100 in this embodiment is improved by 0.04%, with gains in both FF and Isc.

[0050] This embodiment of the invention sets the connection point between the second sub-gate 122 and the first sub-gate 121 at both ends of the first sub-gate 121, which helps to shorten the carrier transport path between the second sub-gate 122 and the first main gate 111, thereby improving the current collection rate.

[0051] It is understood that the first main grid 111 in this embodiment of the present invention is typically located at the edge of the back-contact solar cell 100. During the fabrication of the back-contact solar cell 100, if the pads connected to the external circuit are placed at the edge of the back-contact solar cell 100 (i.e., at the first main grid 111), the back-contact solar cell 100 may experience edge cracking due to stress concentration caused by the pad soldering process, thereby reducing the fabrication yield of the back-contact solar cell 100. Therefore, during the pattern design of the back-contact solar cell 100, the charge carriers collected at the first main grid 111 at the edge are often led to the pads through the main grid extending into the cell. Specifically, refer to... Figure 2 In this embodiment of the invention, the main electrode structure 11 further includes a second main gate 112 extending along the first direction Y and a third main gate 113 extending along the second direction X. The third main gate 113 is connected between the first main gate 111 and the second main gate 112.

[0052] It is understood that the main electrode structure 11 also includes pads (i.e., the second main gate 112 in this invention) connected to external circuits. The pads can gather the charge carriers collected by the interdigitated first sub-gate 121 into a larger contact area, reducing resistance loss. Specifically, part of the first sub-gate 121 is directly connected to the second main gate 112, and this part of the first sub-gate 121 can directly transfer the collected charge carriers to the second main gate 112. Part of the first sub-gate 121 is connected to the second main gate 112 through the first main gate 111, and this part of the first sub-gate 121 first transfers the collected charge carriers to the first main gate 111, and the first main gate 111 then transfers the charge carriers to the second main gate 112 through the third main gate 113.

[0053] Specifically, the second main gate 112 includes a second main gate A 112A and a second main gate B 112B, and the third main gate 113 includes a third main gate A 113A and a third main gate B 113B. The third main gate A 113A is connected between the first main gate A 111A and the second main gate A 112A, and the third main gate B 113B is connected between the first main gate B 111B and the second main gate B 112B.

[0054] Figure 3 This is a schematic diagram of another back-contact solar cell provided in an embodiment of the present invention, with reference to... Figure 3 In this embodiment of the present invention, the width of the second sub-gate 122 in the second direction X is greater than the width of the first sub-gate 121 in the first direction Y.

[0055] This embodiment of the invention incorporates a thickened design for the second sub-gate 122A and the second sub-gate 122B, which helps to further improve the collection and transmission efficiency of charge carriers.

[0056] As a feasible implementation, the width W2 of the second sub-gate 122 in the second direction X and the width W1 of the first sub-gate 121 in the first direction Y satisfy: W2≥1.5×W1.

[0057] Figure 2 and Figure 3 While the design of the second main grid 112 and the third main grid 113 solves the problem of cracking and damage to the back-contact solar cell 100 caused by pad welding, the third main grid 113, made of non-burn-through paste, only serves to transport charge carriers and cannot collect them, which will cause a certain loss in the cell's conversion efficiency. To solve this problem, this invention sets a sub-grid that can collect charge carriers between the first main grid 111 and the second main grid 112. Specifically, Figure 4 This is a schematic diagram of another back-contact solar cell provided in an embodiment of the present invention, with reference to... Figure 4The secondary electrode structure 12 in this embodiment of the present invention further includes a third secondary gate 123 extending along the second direction X. The third secondary gate 123 is connected between the first main gate 111 and the second main gate 112.

[0058] For example, refer to Figure 2 , Figure 3 and Figure 4 In this embodiment of the invention, the third sub-gate 123 includes a third sub-gate A 123A and a third sub-gate B 123B. The third sub-gate A 123A is connected between the first main gate A 111A and the second main gate A 112A to solve the problem that carriers cannot be collected at the third main gate A 113A connected between the first main gate A 111A and the second main gate A 112A, which is beneficial to improving the conversion efficiency of the back contact solar cell 100.

[0059] The third secondary grid 123B is connected between the first primary grid 111B and the second primary grid 112B to solve the problem that carriers cannot be collected at the third primary grid 113B connected between the first primary grid 111B and the second primary grid 112B, which is beneficial to improving the conversion efficiency of the back contact solar cell 100.

[0060] In one feasible implementation, the third sub-gate 123 in this embodiment of the present invention penetrates the second main gate 112 along the second direction X.

[0061] For example, the problem of carriers not being able to be collected at the third main busbar 113A can be solved by grooving the third main busbar 113A and printing a burn-through paste at the grooved location, while also providing a certain gain to the short-circuit current and fill factor of the back-contact solar cell 100. Similarly, the problem of carriers not being able to be collected at the third main busbar 113B can be solved by grooving the third main busbar 113B and printing a burn-through paste at the grooved location, while also providing a certain gain to the short-circuit current and fill factor of the back-contact solar cell 100.

[0062] It should be noted that, in order to ensure that the third sub-gate 123 can fill the slot on the second main gate 112, the width of the slot along the first direction Y can be set to be slightly smaller than the width of the third sub-gate 123.

[0063] To each Figure 3 The back-contact solar cell 100 shown and Figure 4 The back-contact solar cell 100 shown was subjected to IV testing, and the electrical performance data shown in Table 2 below were obtained:

[0064] Table 2

[0065]

[0066] It should be noted that, Figure 3 The back-contact solar cell 100 shown and Figure 4 The back-contact solar cell 100 shown, in addition to Figure 4 The back-contact solar cell 100 shown has the same manufacturing process as the one with an additional third grid 123: laser etching followed by printing. The laser energy and wet weight used in the manufacturing process are identical, and there are no printing defects on the screen. To reduce experimental error and ensure accuracy, 400 cells were taken before laser etching and divided into two groups of 200 cells each for verification. The verification was repeated three times while maintaining the same experimental conditions. In Table 2, Eta represents the conversion efficiency, Uoc represents the open-circuit voltage, Isc represents the short-circuit current, FF represents the fill factor, Rser represents the series resistance, Rshunt represents the parallel resistance, and Irev represents the reverse current. Table 2 shows that the efficiency of the back-contact solar cell 100 in this embodiment is improved by 0.05%, with gains in both FF and Isc.

[0067] refer to Figure 1 , Figure 2 and Figure 3 Along the second direction X, the distance d1 between the first main gate 111A and the first secondary gate 121B satisfies: d1≥0.5mm. Along the second direction X, the distance d2 between the first main gate 111B and the first secondary gate 121A satisfies: d2≥0.5mm.

[0068] For example, considering the offset of screen printing and the manufacturing accuracy of the printing template, along the second direction X, the distance d1 between the first main grid 111A and the first secondary grid 121B satisfies: d1≥0.5mm, and along the second direction X, the distance d2 between the first main grid 111B and the first secondary grid 121A satisfies: d2≥0.5mm.

[0069] Based on the same concept, this utility model also provides a solar cell module. Figure 5 This is a schematic diagram of the structure of a solar cell module provided in an embodiment of the present invention, with reference to... Figure 5 The solar cell module 300 in this embodiment includes the back-contact solar cell 100 provided in any of the above embodiments of this utility model. Therefore, the solar cell module 300 includes the technical features of the back-contact solar cell 100 and has the beneficial effects of the back-contact solar cell 100. The similarities can be referred to the description above.

[0070] Based on the same concept, this utility model embodiment also provides a photovoltaic system. Figure 6 This is a schematic diagram of a photovoltaic system provided in an embodiment of the present invention, with reference to... Figure 6 The photovoltaic system 400 in this embodiment includes the solar cell module 300 provided in the above embodiments of this utility model, and the solar cell module 300 includes the back-contact solar cell 100 provided in any of the above embodiments of this utility model. Therefore, the photovoltaic system 400 includes the technical features of the back-contact solar cell 100 and has the beneficial effects of the back-contact solar cell 100. The similarities can be referred to the description above.

[0071] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A back-contact solar cell, characterized in that, Includes multiple electrode structures; The electrode structure includes a main electrode structure and multiple sub-electrode structures; The main electrode structure includes a first main gate extending along a first direction; the sub-electrode structure includes a plurality of first sub-gates extending along a second direction and a second sub-gate extending along the first direction. The first direction intersects with the second direction; There exists a second sub-gate connected between two adjacent first sub-gates, and the connection point between the second sub-gate and the first sub-gate is located between the two ends of the first sub-gate.

2. The back-contact solar cell according to claim 1, characterized in that, The width of the second sub-gate in the second direction is greater than the width of the first sub-gate in the first direction.

3. The back-contact solar cell according to claim 2, characterized in that, The width W2 of the second sub-gate in the second direction and the width W1 of the first sub-gate in the first direction satisfy: W2≥1.5×W1.

4. The back-contact solar cell according to claim 1, characterized in that, The main electrode structure further includes a second main gate extending along the first direction and a third main gate extending along the second direction; The third main gate is connected between the first main gate and the second main gate.

5. The back-contact solar cell according to claim 4, characterized in that, The sub-electrode structure further includes a third sub-gate extending along the second direction; The third sub-gate is connected between the first main gate and the second main gate.

6. The back-contact solar cell according to claim 5, characterized in that, The third sub-gate penetrates the second main gate along the second direction.

7. The back-contact solar cell according to claim 1, characterized in that, The plurality of electrode structures include at least one first electrode structure and at least one second electrode structure; the main electrode structure includes a first main electrode structure and a second main electrode structure; the sub-electrode structure includes a first sub-electrode structure and a second sub-electrode structure; the first main gate includes a first A main gate and a first B main gate; the first sub-gate includes a first A sub-gate and a first B sub-gate; the second sub-gate includes a second A sub-gate and a second B sub-gate. The first electrode structure includes a first main electrode structure and a plurality of first sub-electrode structures; the first main electrode structure includes a first A main gate extending along the first direction; the first sub-electrode structure includes a plurality of first A sub-gates extending along the second direction and a second A sub-gate extending along the first direction. The second electrode structure includes a second main electrode structure and a plurality of second sub-electrode structures; the second main electrode structure includes a first B main gate extending along the first direction; the second sub-electrode structure includes a plurality of first B sub-gates extending along the second direction and a second B sub-gate extending along the first direction. The first main gate A and the first main gate B are arranged along the second direction; The first sub-gate A and the first sub-gate B are arranged alternately along the first direction.

8. The back-contact solar cell according to claim 7, characterized in that, Along the second direction, the distance d1 between the first main gate A and the first secondary gate B satisfies: d1 ≥ 0.5 mm; Along the second direction, the distance d2 between the first main gate B and the first secondary gate A satisfies: d2≥0.5mm.

9. A solar cell module, characterized in that, Including the back-contact solar cell as described in any one of claims 1-8.

10. A photovoltaic system, characterized in that, Includes the solar cell module as described in claim 9.

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