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

Abstract

The application relates to a back contact solar cell, a solar laminated cell and a photovoltaic module. The back contact solar cell comprises a first pad, a first fine grid, a second fine grid and a first insulating layer. A plurality of first pads are arranged along a first direction. The first fine grid is connected with the first pad. The second fine grid is alternately arranged with the first fine grid along the first direction. The first insulating layer is continuously arranged along the first direction. The first insulating layer is provided with a first opening. The plurality of first pads are located in the first opening, so that the first pad is exposed from the first insulating layer. The continuous arrangement of the first insulating layer reduces the positioning accuracy requirement of the first insulating layer, simplifies the production process of the back contact solar cell, reduces the process difficulty, and enables the first insulating layer to uniformly disperse stress, thereby improving the mechanical performance of the back contact solar cell, reducing the risk of hidden cracking of the back contact solar cell, and further improving the reliability of the back contact solar cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, specifically to a back-contact solar cell, a solar tandem cell, and a photovoltaic module. Background Technology

[0002] Back-contact solar cells are typically coated with insulating adhesive to prevent short circuits. Currently, the reliability of this insulating adhesive is relatively low, and the coating process is complex, thus affecting the reliability of back-contact solar cells and increasing the difficulty of their production. Utility Model Content

[0003] In view of this, this application provides a back-contact solar cell, a solar tandem cell, and a photovoltaic module to solve the problem of low reliability of insulating adhesive in the prior art, while reducing the process difficulty of coating insulating adhesive.

[0004] In a first aspect, embodiments of this application provide a back-contact solar cell, including a first pad, a first grid, a second grid, and a first insulating layer. A plurality of first pads are arranged along a first direction, the first grid is connected to the first pad, the second grid and the first grid are arranged alternately along the first direction, the first insulating layer is continuously disposed along the first direction, the first insulating layer has a first opening, and a plurality of first pads are located within the first opening, so that the first pads are exposed from the first insulating layer.

[0005] In one possible implementation, along the second direction, a first isolation portion is provided between the first pad and the second fine gate, and the first insulating layer covers the first isolation portion along the third direction, wherein the width of the first isolation portion satisfies: 20μm≤W≤120μm.

[0006] In one possible implementation, the first insulating layer extends toward the direction of the second fine gate and covers the end of the second fine gate in the third direction.

[0007] In one possible implementation, the first insulating layer covers the entire structure of the second fine gate along the third direction.

[0008] In one possible implementation, the first insulating layer covers at least a portion of the structure of the first fine gate along the third direction.

[0009] In one possible implementation, the first insulating layer includes a first insulating segment that covers a portion of the structure of the first fine gate along the third direction, and the dimension L1 of the first insulating segment along the second direction satisfies: 0 < L1 ≤ 600 μm.

[0010] In one possible implementation, the back-contact solar cell further includes a second isolation portion and a second insulating layer. The second isolation portion is located between adjacent first and second grids along the first direction. The second isolation portion is connected to the first isolation portion. The second insulating layer covers the second isolation portion along the third direction and is connected to the first insulating layer.

[0011] In one possible implementation, the back-contact solar cell includes a substrate along the first direction, the substrate including a first surface and a second surface disposed opposite to each other, the first insulating layer, the second insulating layer, the first fine grid, the second fine grid and the first pad are all disposed on the first surface, and the first isolation portion and the second isolation portion are both grooves extending from the first surface toward the second surface.

[0012] In one possible implementation, a portion of the structure of the first insulating layer extends into the first insulating portion, and / or a portion of the structure of the second insulating layer extends into the second insulating portion.

[0013] In one possible implementation, the first opening includes a plurality of first sub-openings, which are spaced apart along the first direction and correspond one-to-one with a plurality of first pads.

[0014] In one possible implementation, there is a gap between the outer peripheral wall of the first pad and the inner peripheral wall of the corresponding first sub-opening, or the outer peripheral wall of the first pad and the inner peripheral wall of the corresponding first sub-opening are connected.

[0015] In one possible implementation, the back-contact solar cell includes a main grid, wherein the main grid connected to the first pad is a first main grid, the first main grid includes a first segment and a second segment arranged along the first direction, the first segment being connected to the second segment, the projection of the first segment along the third direction being located within the first pad, the first segment being connected to the first pad, the first segment being exposed from the first sub-opening, and the second segment being covered by the first insulating layer, or, a portion of the structure of the second segment being exposed from the first sub-opening.

[0016] In one possible implementation, the first opening further includes a second sub-opening, the first sub-opening and the second sub-opening are alternately arranged along the first direction, and the first sub-opening and the second sub-opening are spaced apart; or, the first sub-opening and the second sub-opening are in communication, the back contact solar cell includes a first sub-region and a second sub-region alternately arranged along the first direction, the first pads are correspondingly disposed on the first sub-region, and at least a portion of the second sub-region is exposed from the second sub-opening.

[0017] In one possible implementation, the back-contact solar cell further includes a third insulating layer and a second pad, the second pad being connected to the second grid, the third insulating layer being continuously disposed along the first direction, the third insulating layer having a second opening, a plurality of second pads being arranged along the first direction, the plurality of second pads being located within the second opening, so that the second pads are exposed from the third insulating layer.

[0018] In one possible implementation, a third isolation portion is provided between the second pad and the first fine gate along the second direction, and the third insulating layer covers the third isolation portion along the third direction.

[0019] Secondly, embodiments of this application provide a solar tandem cell, including a crystalline silicon bottom cell and a perovskite top cell, wherein the crystalline silicon bottom cell includes a back-contact solar cell as described above, and the perovskite top cell is electrically connected to the crystalline silicon bottom cell.

[0020] Thirdly, embodiments of this application provide a photovoltaic module, the photovoltaic module including a cover plate, an encapsulation layer and a battery string, the battery string including a plurality of back-contact solar cells as described above, or the battery string including a plurality of solar tandem cells as described above.

[0021] The beneficial effects of this application are as follows: It makes it easier to control the amount of the first insulating layer used, thereby forming a uniform first insulating layer on the back-contact solar cell, improving the reliability of the first insulating layer, and reducing the requirements for the positioning accuracy of the first insulating layer, thus simplifying the process of coating the first insulating layer and reducing the complexity of the back-contact solar cell manufacturing process. Simultaneously, the continuous distribution of the first insulating layer allows for uniform stress dispersion, improving the mechanical properties of the back-contact solar cell, reducing the risk of microcracks, and increasing the contact area between the first insulating layer and the substrate of the back-contact solar cell, reducing the risk of delamination between the first insulating layer and the substrate, and improving the reliability of the back-contact solar cell.

[0022] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a back-contact solar cell provided in an embodiment of this application;

[0025] Figure 2 for Figure 1 A partial schematic diagram of a solar cell with a center-back contact.

[0026] Figure 3 This is a partial schematic diagram of an embodiment of the present application in which the first insulating layer is disposed on the back contact solar cell;

[0027] Figure 4 This is a partial schematic diagram of another embodiment of the present application in which the first insulating layer is disposed on the back contact solar cell;

[0028] Figure 5 This is a partial schematic diagram of a first insulating layer disposed on a back-contact solar cell in another embodiment of this application;

[0029] Figure 6 This is a partial schematic diagram of a first isolation portion and a second isolation portion disposed on a back-contact solar cell in one embodiment of this application;

[0030] Figure 7 This is a partial schematic diagram of a first insulating layer and a second insulating layer disposed on a back-contact solar cell in one embodiment of this application;

[0031] Figure 8 A schematic diagram of a back-contact solar cell provided in another embodiment of this application;

[0032] Figure 9 for Figure 8 A partial schematic diagram of a solar cell with a center-back contact.

[0033] Figure 10 This is a partial schematic diagram of a back-contact solar cell with a main grid provided in one embodiment of this application;

[0034] Figure 11 This is a partial schematic diagram of a back-contact solar cell with a main grid provided in another embodiment of this application;

[0035] Figure 12This is a partial schematic diagram of a back-contact solar cell with a main grid provided in another embodiment of this application;

[0036] Figure 13 This is a schematic diagram of a back-contact solar cell without a grid, provided in one embodiment of this application;

[0037] Figure 14 for Figure 13 A partial schematic diagram of a solar cell with a center-back contact.

[0038] Figure 15 This is a partial schematic diagram of a back-contact solar cell without a main grid in one embodiment of this application;

[0039] Figure 16 This is a partial schematic diagram of a back-contact solar cell without a main grid in another embodiment of this application;

[0040] Figure 17 This is a schematic diagram of a solar tandem cell in one embodiment of this application;

[0041] Figure 18 This is a schematic diagram of a photovoltaic module in one embodiment of this application.

[0042] Figure label:

[0043] 10-Back contact solar cell; 11-First insulating layer; 111-First insulating segment; 112-First opening; 1121-First sub-opening; 1122-Second sub-opening; 1122a-First opening segment; 1122b-Second opening segment; 12-First pad; 13-First grid; 14-Second grid; 15-First isolation portion; 16-Second isolation portion; 17-Second insulating layer; 18-Third insulating layer; 181-Second opening; 1811-Third sub-opening; 19-Second pad; 31-First main grid; 311-First segment; 312-Second segment; 32-Second main grid; 321-Third segment; 322-Fourth segment;

[0044] 20-Solar tandem cell; 21-Crystalline silicon bottom cell; 22-Perovskite top cell;

[0045] 100 - Photovoltaic module; 101 - First cover plate; 102 - First encapsulation layer; 103 - Battery string; 105 - Second encapsulation layer; 106 - Second cover plate. Detailed Implementation

[0046] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0047] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0048] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0049] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0050] Back-contact solar cells have all metal electrodes located on the back side of the cell, ensuring the front side is not obstructed by the electrodes. This increases the area for absorbing sunlight, reduces optical losses, and thus improves photoelectric conversion efficiency. An insulating adhesive is applied to the back side of the back-contact solar cell to provide electrical isolation and prevent short circuits. Currently, the reliability of this insulating adhesive is relatively low, and the coating process is complex, affecting the reliability of back-contact solar cells and increasing the difficulty of their manufacturing.

[0051] like Figure 1 As shown, this application embodiment provides a back-contact solar cell 10, which includes a first fine grid 13 and a second fine grid 14, the first fine grid 13 and the second fine grid 14 being alternately arranged along a first direction X. The first fine grid 13 and the second fine grid 14 are metal electrodes of the back-contact solar cell 10. The first fine grid 13 can be a positive electrode, or the first fine grid 13 can be a negative electrode, and the electrode polarity of the second fine grid 14 is opposite to that of the first fine grid 13.

[0052] The first pad 12 is electrically connected to the first fine grid 13. The first pad 12 is used to realize the electrical connection between the back-contact solar cell 10 and an external circuit. Specifically, the first pad 12 provides a welding point for a solder tape (not shown in the figure) to realize the connection between the solder tape and the back-contact solar cell 10, so that the current of the first fine grid 13 is transmitted through the solder tape. The number of the first pads 12 can be two, four, six or more. The embodiment of the present application does not limit the number of the first pads 12. The first pads 12 are arranged along the first direction X, and each first pad 12 is connected to the corresponding first fine grid 13. Along the second direction Y, the first pads 12 and the second fine grids 14 are arranged at intervals to avoid the possibility of short circuit of the back-contact solar cell 10 caused by their contact.

[0053] Please refer to Figure 2 simultaneously. The first insulating layer 11 can realize the electrical isolation between the first pad 12 and the second fine grid 14. The first insulating layer 11 is continuously arranged along the first direction X. The first insulating layer 11 has a first opening 112, and the first opening 112 is a hollow window structure. The above-mentioned first pad 12 is located in the first opening 112, and the first pad 12 is exposed from the first insulating layer 11. That is to say, the first insulating layer 11 opens a window at the position corresponding to the first pad 12 so that the first insulating layer 11 does not cover the first pad 12 to ensure the normal operation of the first pad 12. Among them, the first insulating layer 11 can be an insulating colloid, which can be printed or laid on the back-contact solar cell 10. The first opening 112 can be a closed annular opening. For example, the shape of the first opening 112 can be a "square" shape or other shapes.

[0054] The first insulating layer 11 is continuously arranged along the first direction X, so that the first pads 12 arranged along the first direction X can realize the electrical isolation from the second fine grids 14 through the same first insulating layer 11. Compared with discrete distribution, continuous distribution is easier to control the amount of the first insulating layer 11, so as to form a uniform first insulating layer 11 on the back-contact solar cell 10, improve the reliability of the first insulating layer 11, and reduce the requirement for the positioning accuracy of the first insulating layer 11 and the difficulty of the coating process of the first insulating layer 11, thereby simplifying the production process of the back-contact solar cell 10 and reducing the process difficulty. At the same time, the continuous distribution of the first insulating layer 11 enables the first insulating layer 11 to evenly disperse stress, thereby improving the mechanical properties of the back-contact solar cell 10, reducing the risk of hidden cracks in the back-contact solar cell 10, and also increasing the contact area between the first insulating layer 11 and the substrate of the back-contact solar cell 10, reducing the risk of delamination between the first insulating layer 11 and the substrate, and improving the reliability of the back-contact solar cell​​​​As shown, in some embodiments, the first pad 12 is exposed from the first opening 112, and a first isolation portion 15 is provided between the first pad 12 and the second fine gate 14 along the second direction Y. The first isolation portion 15 serves to electrically isolate the first pad 12 and the second fine gate 14, reducing the risk of short circuit in the back-contact solar cell 10. The width W of the first isolation portion 15 (i.e., the dimension of the first isolation portion 15 along the second direction Y) satisfies: 20μm ≤ W ≤ 120μm. For example, W can be 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, or 120μm, or other values ​​within the above range. By limiting the width of the first isolation portion 15, the first isolation portion 15 can play a stable and reliable electrical isolation role between the first pad 12 and the second fine grid 14, thereby reducing the risk of short circuit in the back contact solar cell 10.

[0056] The first insulating layer 11 covers the first isolation portion 15 along the third direction Z. The third direction Z can be the thickness direction of the back-contact solar cell 10, meaning the projection of the first isolation portion 15 along the third direction Z falls within the first insulating layer 11. The first insulating layer 11 protects the first isolation portion 15, preventing it from being exposed and thus isolating it from the outside environment. This reduces the risk of failure due to external factors (such as moisture and dust), improving the reliability of the first isolation portion 15 and ensuring its stable isolation function. This also reduces the risk of short circuits or damage to the back-contact solar cell 10, further enhancing its reliability. Simultaneously, moisture intrusion into the first isolation portion 15 can easily lead to oxidation of the silicon substrate of the back-contact solar cell 10. Therefore, by covering the first isolation portion 15, the first insulating layer 11 also protects the silicon substrate, effectively blocking the path of moisture intrusion, reducing the risk of oxidation of the silicon substrate surface, and ensuring the electrical performance of the back-contact solar cell 10. In addition, during the use of the back contact solar cell 10, the first insulating layer 11 can block ultraviolet rays to a certain extent, reducing the possibility of excessive ultraviolet energy damaging the first insulating part 15 and the silicon substrate, thereby extending the service life of the back contact solar cell 10.

[0057] like Figure 4As shown, in one possible implementation, a first insulating layer 11 with a first opening 112 extends toward the second fine gate 14 and covers the end of the second fine gate 14 in a third direction Z, i.e., the first insulating layer 11 can cover the end of the second fine gate 14 facing the first pad 12. As mentioned above, the first pad 12 can be connected to the solder ribbon. During solder ribbon connection and subsequent use, the solder ribbon is prone to misalignment, which can easily cause the solder ribbon to come into contact with the second fine gate 14 and cause a short circuit. The first insulating layer 11 covers the end of the second fine gate 14, thereby isolating the end of the second fine gate 14, reducing the possibility of short circuit of the back contact solar cell 10 due to contact between the solder ribbon and the end of the second fine gate 14, thereby improving the reliability of the back contact solar cell 10.

[0058] like Figure 5 As shown, in one possible embodiment, the first insulating layer 11 with the first opening 112 covers the entire structure of the second grid 14 along the third direction Z. In this embodiment, the first insulating layer 11 can simultaneously cover the second grid 14 and the first isolation portion 15. The first insulating layer 11 can completely cover the second grid 14, providing protection and isolation for the second grid 14, improving its corrosion and aging resistance. Simultaneously, the first insulating layer 11 also provides mechanical protection for the second grid 14, reducing the possibility of the second grid 14 being scratched during lamination or handling of the back contact solar cell 10. Furthermore, by increasing the coverage area of ​​the first insulating layer 11, the possibility of a short circuit in the back contact solar cell 10 caused by the solder ribbon (not shown) connected to the first pad 12 contacting the second grid 14 is further reduced, thereby improving the reliability of the back contact solar cell 10.

[0059] In other embodiments, the first insulating layer may cover part of the structure of the second fine gate and the first isolation portion in a third direction. Specifically, the first insulating layer may cover the end and the middle of the second fine gate. That is, in addition to covering the end of the second fine gate, the first insulating layer may also cover other positions of the second fine gate, but does not cover the entire second fine gate.

[0060] like Figure 5 As shown, in one possible implementation, the first insulating layer 11, having a first opening 112, covers at least a portion of the structure of the first grid 13 along the third direction Z. That is, the first insulating layer 11 may cover a portion of the structure of the first grid 13, or the first insulating layer 11 may completely cover the first grid 13. Covering the first grid 13 with the first insulating layer 11 improves the reliability of electrical isolation between grids of different electrode polarities on the back side of the back contact solar cell 10, thereby improving the reliability of the back contact solar cell 10.

[0061] like Figure 5 As shown, the first insulating layer 11 can simultaneously cover part of the structure of the first fine gate 13, the end of the second fine gate 14, and the first isolation portion 15.

[0062] In some embodiments, the first insulating layer may simultaneously cover a portion of the structure of the first fine gate and the first isolation portion. In other embodiments, the first insulating layer may simultaneously cover the entire first fine gate, the entire second fine gate, and the first isolation portion.

[0063] Continue as Figure 5 As shown, in one possible implementation, the first insulating layer 11 having a first opening 112 includes a first insulating segment 111, the first insulating segment 111 covering a portion of the structure of the first fine gate 13 along the third direction Z, and the dimension L1 of the first insulating segment 111 along the second direction Y satisfies: 0 < L1 ≤ 600 μm.

[0064] The dimension L1 of the first insulating layer 11 is the length of the first fine grid 13 covered by the first insulating layer 11. L1 can be 5μm, 10μm, 50μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, or 600μm, or other values ​​within the above range. The first insulating segment 111 can extend along the first direction X and cover the first isolation portion 15. By limiting the dimension L1 of the first insulating layer 11, the amount of the first insulating layer 11 used can be reduced while ensuring that the first insulating layer 11 plays a reliable electrical isolation role, thereby reducing the production cost of the back contact solar cell 10.

[0065] like Figure 5 As shown, Figure 5 Only a portion of the structure of the first fine grid 13 is shown. In some embodiments, the dimension of the first fine grid 13 along the second direction Y is L2, and the dimension of the first insulating layer 11 along the second direction Y is L3. The relationship between L3 and L2 satisfies: L3 > 0.5L2 + 600, that is, L3 is greater than 0.5 times the sum of L2 and 600 μm. By limiting the dimension of the first insulating layer 11 along the second direction Y (i.e., the width of the first insulating layer 11), it is ensured that the first insulating layer 11 covers the first isolation portion 15 while saving the amount of the first insulating layer 11 used, thereby reducing the production cost of the back contact solar cell 10.

[0066] like Figure 6As shown, in one possible embodiment, the back-contact solar cell 10 further includes a second isolation portion 16. The second isolation portion 16 is located along the first direction X between adjacent first grid 13 and second grid 14, and is connected to the first isolation portion 15. The second isolation portion 16 provides electrical isolation between the first grid 13 and the second grid 14, reducing the risk of short circuits in the back-contact solar cell 10. A second insulating layer 17 covers the second isolation portion 16, meaning that the projection of the second isolation portion 16 along the third direction Z falls within the second insulating layer 17.

[0067] Please also refer to Figure 7 The back-contact solar cell 10 further includes a second insulating layer 17, which covers the second isolation portion 16 along a third direction Z. The second insulating layer 17 is connected to the first insulating layer 11 having a first opening 112. In this embodiment, the first insulating layer 11 may at least cover the first isolation portion 15.

[0068] The second isolation section 16 achieves electrical isolation between the first fine grid 13 and the second fine grid 14. Under the action of the first isolation section 15 and the second isolation section 16, the risk of short circuits in the back-contact solar cell 10 is further reduced, improving the reliability of the back-contact solar cell 10. The second insulating layer 17 protects the second isolation section 16, preventing it from being exposed and thus isolating it from the outside environment. This reduces the risk of failure due to external factors (such as moisture and dust), improving the reliability of the second isolation section 16 and ensuring its stable isolation function. This further reduces the risk of short circuits or damage to the back-contact solar cell 10, thereby improving its overall reliability. Simultaneously, by covering the second isolation section 16, the second insulating layer 17 helps block the path of moisture intrusion, reducing the risk of oxidation of the silicon substrate of the back-contact solar cell 10 caused by moisture intrusion. This also protects the silicon substrate, ensuring the electrical performance of the back-contact solar cell 10. In addition, the second insulating layer 17 protects the silicon substrate of the back contact solar cell 10, reducing the possibility of excessive ultraviolet energy damaging the second insulating part 16 and the silicon substrate, thereby extending the service life of the back contact solar cell 10.

[0069] In one possible implementation, the back-contact solar cell further includes a substrate, which may be a silicon substrate. Along a first direction, the substrate includes a first surface and a second surface disposed opposite to each other. A first insulating layer, a second insulating layer, a first fine grid, a second fine grid, and a first pad are all disposed on the first surface. The first isolation portion and the second isolation portion are both grooves extending from the first surface toward the second surface.

[0070] The first surface can be the back side of the back-contact solar cell. The first surface includes alternating P-type and N-type doped regions. The first and second fine grids are located on the P-type doped region and the other on the N-type doped region, respectively. The first and second isolation portions achieve electrical isolation between regions of different conductivity types (i.e., P-type and N-type doped regions), reducing the risk of leakage current caused by the formation of a PN junction between the P-type and N-type doped regions, which could affect the normal operation of the back-contact solar cell. The first isolation portion can be a trench structure located between the second fine grid and the first pad, and the second isolation portion can also be a trench structure located between the first and second fine grids. The first and second isolation portions are also referred to as GAP regions. Setting the first and second isolation portions as trench structures improves their reliability, providing reliable electrical isolation and reducing the risk of short circuits in the back-contact solar cell.

[0071] As mentioned above, both the first isolation portion and the second isolation portion can be a groove. In some embodiments, the first insulating layer with the first opening can be an insulating colloid, which covers the surface of the first isolation portion to isolate the space inside the first isolation portion from the outside. The second insulating layer connected to the first insulating layer can also be an insulating colloid, which covers the surface of the second isolation portion to isolate the space inside the second isolation portion from the outside. That is, the insulating colloid can not extend into the space inside the first isolation portion and the second isolation portion.

[0072] In one possible implementation, a portion of the structure of the first insulating layer extends into the first insulating portion, and / or a portion of the structure of the second insulating layer extends into the second insulating portion.

[0073] The first isolation section can be the aforementioned tank. A first insulating layer with a first opening covers the first isolation section, and a portion of the first insulating layer can extend into the first isolation section. This enhances the sealing effect of the first insulating layer, reduces the intrusion of moisture and other impurities into the first isolation section, and improves its reliability. Simultaneously, the first insulating layer acts as a buffer within the first isolation section, strengthening its structural strength, reducing the possibility of microcracks or fragmentation in the back-contact solar cell, and extending its lifespan.

[0074] The second insulating part can be a groove. While the second insulating layer connected to the first insulating layer covers the second insulating layer, a part of the structure of the second insulating layer can extend into the second insulating part. The technical effect of the second insulating layer extending into the second insulating part is the same as that of the first insulating layer extending into the first insulating part, and will not be described in detail here.

[0075] As mentioned above, both the first and second insulating layers can be insulating colloids. During the printing of the first insulating layer, it can have a certain degree of fluidity. Under the influence of its own gravity, the portion of the first insulating layer covering the first insulating part tends to move inwards towards the first insulating part, allowing a portion of the structure of the first insulating layer to extend into the first insulating part. Similarly, during the printing of the second insulating layer, it can also have a certain degree of fluidity. Under the influence of its own gravity, the portion of the second insulating layer covering the second insulating part tends to move inwards towards the second insulating part, allowing a portion of the structure of the second insulating layer to extend into the second insulating part.

[0076] In some embodiments, the first insulating layer and the second insulating layer described above can be integrally formed, and the first insulating layer and the second insulating layer can be simultaneously printed or deposited on the back contact solar cell. In other embodiments, the first insulating layer and the second insulating layer can be separately disposed, that is, the first insulating layer and the second insulating layer can be sequentially printed or deposited on the back contact solar cell.

[0077] In a back-contact solar cell, electrical isolation between the solder joint and the grid with opposite electrode polarity can be achieved through an isolation portion, and each isolation portion can be covered by an insulating layer at the corresponding location. The first pad connected to the first grid, the first isolation portion located between the first pad and the second grid, and the first insulating layer have been described above. The second pad connected to the second grid, the third isolation portion located between the second pad and the first grid, and the third insulating layer will be described in detail below.

[0078] like Figure 1 and 2 As shown, in one possible embodiment, the back contact solar cell 10 further includes a third insulating layer 18 and a second pad 19. The third insulating layer 18 is continuously disposed along a first direction X. The third insulating layer 18 has a second opening 181, which can be an annular opening. A plurality of second pads 19 are arranged along the first direction X. The plurality of second pads 19 are all located within the second opening 181 so that the second pads 19 are exposed from the third insulating layer 18. The second pads 19 are connected to the second grid 14.

[0079] The second pad 19 provides a soldering point for the solder strip (not shown in the figure), enabling the connection between the solder strip and the back contact solar cell 10, thereby allowing the current of the second grid 14 to be transmitted through the solder strip. The number of second pads 19 can be two, four, six, or more; this embodiment does not limit the number of second pads 19. The second pads 19 are arranged along the first direction X, and each second pad 19 is connected to the corresponding second grid 14.

[0080] The third insulating layer 18 is continuously disposed along the first direction X, so that the second pads 19 arranged along the first direction X can be electrically isolated from the first grid 13 through the same third insulating layer 18, which helps to simplify the printing steps of the third insulating layer 18, thereby simplifying the production process of the back contact solar cell 10. The effect of the continuous distribution of the third insulating layer 18 is the same as the effect of the continuous distribution of the first insulating layer 11, which will not be described in detail here.

[0081] In some embodiments, along the second direction Y, the second pad 19 and the first fine gate 13 are spaced apart, and a third isolation portion (not shown in the figure) is provided between the second pad 19 and the first fine gate 13, and the third insulating layer 18 covers the third isolation portion along the third direction Z.

[0082] A third isolation portion is provided on the side of the first fine grid 13 near the second pad 19 along the second direction Y. As mentioned above, the back contact solar cell includes a substrate, and along the first direction, the substrate includes a first surface and a second surface disposed opposite to each other. The third isolation portion can be a groove extending from the first surface toward the second surface. Like the first and second isolation portions, the third isolation portion can achieve electrical isolation between regions of different conductivity types (i.e., P-type doped regions and N-type doped regions). The third isolation portion can also be referred to as a GAP region. The third isolation portion plays a role in electrical isolation between the second pad 19 and the first fine grid 13, reducing the risk of short circuits in the back contact solar cell 10. The third insulating layer 18 covers the third isolation portion along the third direction Z, that is, the projection of the third isolation portion along the third direction Z falls within the third insulating layer 18.

[0083] The third insulating layer 18 isolates the third isolation part from the outside world. That is, the third insulating layer 18 seals the third isolation part, reducing the risk of failure of the third isolation part due to external factors (such as moisture, dust, etc.), thereby improving the reliability of the third isolation part and enabling it to play a stable isolation role. This reduces the risk of short circuit or even damage to the back contact solar cell 10, thereby improving the reliability of the back contact solar cell 10.

[0084] As can be seen from the above, in a back-contact solar cell, the first pad is exposed from the continuously arranged first insulating layer, the second pad is exposed from the continuously arranged third insulating layer, the first isolation part can be covered by the first insulating layer, and the third isolation part can be covered by the third insulating layer, so as to reduce the risk of failure of each isolation part and thus improve the reliability of the back-contact solar cell.

[0085] In some embodiments, the third insulating layer having the second opening extends toward the direction of the first fine grid and covers the end of the first fine grid in the third direction. That is, the third insulating layer can cover the end of the first fine grid facing the second pad, so as to reduce the possibility of short circuit of the back contact solar cell caused by the solder ribbon contacting the end of the first fine grid, thereby improving the reliability of the back contact solar cell.

[0086] As mentioned above, the purpose of the first opening in the first insulating layer and the second opening in the third insulating layer is to expose the pads to ensure their normal use. The structure of the first and second openings will be described in detail below.

[0087] like Figure 8 and Figure 9 As shown, in some embodiments, the first opening 112 of the first insulating layer 11 includes a plurality of first sub-openings 1121 spaced apart along the first direction X. The first sub-openings 1121 can be annular openings. The first sub-openings 1121 correspond one-to-one with the first pads 12. The first pads 12 are exposed from the corresponding first sub-openings 1121, so that the first insulating layer 11 does not cover the first pads 12. That is, the first insulating layer 11 can be arranged around the first pads 12, and the first insulating layer 11 does not cover the first pads 12.

[0088] By setting a first sub-opening 1121 corresponding one-to-one with the first pad 12, the first pad 12 is exposed from the first insulating layer 11, allowing the first pad 12 to connect normally with the solder strip (not shown in the figure). Simultaneously, this design allows the first insulating layer 11 to be printed or laid as a single unit on the back contact solar cell 10. That is, the first insulating layer 11 does not need to be divided into multiple parts for distributed printing to avoid the first pads 12. In other words, multiple first pads 12 arranged along the first direction X can achieve electrical isolation from the second grid through the same first insulating layer 11, simplifying the printing steps of the first insulating layer 11 and thus simplifying the manufacturing process of the back contact solar cell 10. Continuing as... Figure 9As shown, there is a gap between the outer peripheral wall of the first pad 12 and the inner peripheral wall of its corresponding first sub-opening 1121, meaning the opening area of ​​the first sub-opening 1121 is larger than the area of ​​the first pad 12, resulting in a certain gap between the first insulating layer 11 and the outer peripheral surface of the first pad 12. As mentioned above, the first insulating layer 11 can be an insulating colloid. During the printing process of the insulating colloid, the colloid may overflow and cover the first pad 12, thus affecting the normal and stable connection between the first pad 12 and the solder ribbon (not shown in the figure). Therefore, reserving a certain gap between the first pad 12 and the side wall of the first sub-opening 1121 provides space for the overflow or displacement of the first insulating layer 11, reducing the possibility of the first insulating layer 11 contaminating the first pad 12, ensuring the normal use of the first pad 12, and improving the reliability of the back contact solar cell 10.

[0089] Continue as Figure 9 As shown, the second opening 181 of the third insulating layer 18 includes a plurality of third sub-openings 1811 spaced apart along the first direction X. Each third sub-opening 1811 can be annular. Each third sub-opening 1811 corresponds one-to-one with a second pad 19, and the second pad 19 is exposed through its corresponding third sub-opening 1811, allowing the third insulating layer 18 to not cover the second pad 19. There is a gap between the outer peripheral wall of the second pad 19 and the inner peripheral wall of its corresponding third sub-opening 1811, meaning the opening area of ​​the third sub-opening 1811 is larger than the area of ​​the second pad 19. This facilitates the normal use of the second pad 19 and reduces the possibility of the second pad 19 being contaminated by the third insulating layer 18.

[0090] In some embodiments, the outer peripheral wall of the first pad is connected to the inner peripheral wall of its corresponding first sub-opening, meaning the area of ​​the first sub-opening can be the same as the area of ​​the first pad. In some embodiments, the outer peripheral wall of the second pad is connected to the inner peripheral wall of its corresponding second opening, meaning the area of ​​the second opening can be the same as the area of ​​the second pad. Due to the printing or layup process, the insulating layers may overflow or shift, causing the insulating layer to cover the edge of the pad. In other words, the area of ​​the sub-opening can be slightly smaller than the area of ​​the corresponding pad, as long as the pads can be used normally.

[0091] In some embodiments, such as Figure 8 and Figure 9As shown, the first opening 112 of the first insulating layer 11 includes a plurality of first sub-openings 1121 spaced apart along the first direction X, and the second opening 181 of the third insulating layer 18 includes a plurality of third sub-openings 1811 spaced apart along the first direction X. The first insulating layer 11 can cover the first isolation portion (not shown in the figure), and the third insulating layer 18 can cover the third isolation portion (not shown in the figure).

[0092] The first surface of the aforementioned back-contact solar cell includes alternating first and second doped regions, one of which is a P-type doped region and the other is an N-type doped region. The first doped region includes alternating first and second sub-regions along a first direction, and the plurality of first pads can be correspondingly disposed within the first sub-region. The second doped region includes alternating third and fourth sub-regions along the first direction, and the plurality of second pads can be correspondingly disposed within the third sub-region.

[0093] The back-contact solar cell can be provided with a first main grid and a second main grid. The first main grid is connected to a first fine grid and is used to collect the current of the first fine grid for current collection. The second main grid is connected to a second fine grid and is used to collect the current of the second fine grid for current collection. The first pad is connected to the first main grid and the second pad is connected to the second main grid. The solder strips are connected to the main grid through the corresponding pads.

[0094] The first main gate can be located within the first doped region. The first main gate extends along a first direction and includes alternating first and second segments along the first direction. The first segment is located within a first sub-region and is connected to a first pad to achieve current transmission. The second segment is located within a second sub-region and is connected to the first segment. The second main gate can be located within the second doped region. The second main gate extends along the first direction and includes alternating third and fourth segments along the first direction. The third segment is located within a third sub-region and is connected to a second pad to achieve current transmission. The fourth segment is located within a fourth sub-region and is connected to the third segment.

[0095] Continue as Figure 8 and Figure 9As shown, the first segment 311 of the first main gate 31 is connected to the first pad 12. Along the third direction Z, the projection of the first segment 311 can be located within the first pad 12, and the first segment 311 is exposed through the first sub-opening 1121. A portion of the structure of the second segment 312 of the first main gate 31 can be exposed through the first sub-opening 1121, while another portion of the structure of the second segment 312 can be covered by the first insulating layer 11. That is, a portion of the structure of the first main gate 31 can be exposed to the first insulating layer through the first sub-opening 1121, while the other portion is covered by the first insulating layer 11. This ensures current transmission in the back-contact solar cell while reducing the possibility of short circuits in the back-contact solar cell, thereby improving the reliability of the back-contact solar cell.

[0096] The third segment 321 of the second main gate 32 is connected to the second pad 19. Along the third direction Z, the projection of the third segment 321 can be located within the second pad 19, and the third segment 321 is exposed through the third sub-opening 1811. A portion of the structure of the third segment 321 of the second main gate 32 can be exposed through the third sub-opening 1811, while another portion of the structure can be covered by the third insulating layer 18. In other words, a portion of the structure of the second main gate 32 is exposed to the third insulating layer 18 through the third sub-opening 1811, while the other portion is covered by the third insulating layer 18. This reduces the risk of short circuits in the back contact solar cell 10 and improves the reliability of the back contact solar cell 10.

[0097] like Figure 10 As shown, in some embodiments, the first opening of the first insulating layer 11 includes a first sub-opening 1121. As mentioned above, the first segment 311 of the first main gate 31 is connected to the first pad 12. Along the third direction Z, the projection of the first segment 311 can be located within the first pad 12. The first segment 311 of the first main gate 31 is exposed from the first sub-opening 1121, while the second segment 312 of the first main gate 31 is covered by the first insulating layer 11. That is, only the part of the first main gate 31 connected to the first pad 12 is exposed from the first insulating layer 11, while the other parts are all covered by the first insulating layer 11. This increases the area of ​​the first main gate 31 covered by the first insulating layer 11, thereby ensuring current transmission in the back contact solar cell 10 while reducing the risk of short circuit in the back contact solar cell 10.

[0098] exist Figure 10 In the structure of the back-contact solar cell shown, the first insulating layer 11 can cover the first insulating portion (not shown in the figure).

[0099] In some embodiments, the third segment of the second main gate is exposed from the second sub-opening, while the fourth segment of the second main gate is covered by the third insulating layer. That is, only the portion of the second main gate connected to the second pad is exposed from the third insulating layer, while the other portions are covered by the third insulating layer.

[0100] like Figure 11 As shown, in some embodiments, the first opening 112 of the first insulating layer 11 includes a first sub-opening 1121 and a second sub-opening 1122. Both the first sub-opening 1121 and the second sub-opening 1122 are annular openings. The first sub-opening 1121 and the second sub-opening 1122 are arranged alternately along the first direction X, and there is a gap between the first sub-opening 1121 and the second sub-opening 1122, that is, the first sub-opening 1121 and the second sub-opening 1122 are not connected. The first sub-opening 1121 corresponds one-to-one with the first pad 12, and the first pad 12 is exposed from the corresponding first sub-opening 1121. As mentioned above, the first main gate 31 includes a first segment 311 and a second segment 312 that are connected to each other. At least a portion of the structure of the first segment 311 can be exposed from the first sub-opening 1121, and at least a portion of the structure of the second segment 312 can be exposed from the second sub-opening 1122. That is, at least a portion of the second sub-region can be exposed from the second sub-opening.

[0101] In the second direction Y, the size of the first sub-opening 1121 and the second sub-opening 1122 can be the same or different. Optionally, along the second direction Y, the size of the first sub-opening 1121 can be larger than the size of the second sub-opening 1122.

[0102] The first insulating layer 11 is provided with a second sub-opening 1122, which helps to save the amount of the first insulating layer 11 used, thereby reducing the production cost of the back contact solar cell 10.

[0103] exist Figure 11 In the structure of the back-contact solar cell shown, the first insulating layer 11 can cover the first insulating portion (not shown in the figure).

[0104] In some embodiments, the second opening of the third insulating layer includes a third sub-opening and a fourth sub-opening, both of which can be annular openings. The third and fourth sub-openings are alternately arranged along a first direction, and there is a gap between them, meaning that the third and fourth sub-openings are not connected. Each third sub-opening corresponds one-to-one with a second pad, and the second pad is exposed from its corresponding third sub-opening. The second main gate includes interconnected third and fourth segments, with at least a portion of the third segment and at least a portion of the fourth segment exposed from the third sub-opening. In the second direction, the dimensions of the third and fourth sub-openings can be the same or different; optionally, along the second direction, the size of the third sub-opening can be larger than the size of the fourth opening. In these embodiments, the third insulating layer can cover the third isolation portion.

[0105] like Figure 12 As shown, the first opening 112 of the first insulating layer 11 includes a first sub-opening 1121 and a second sub-opening 1122. Both the first sub-opening 1121 and the second sub-opening 1122 can be annular openings. The first sub-opening 1121 and the second sub-opening 1122 are arranged alternately along the first direction X, and the first sub-opening 1121 and the second sub-opening 1122 are interconnected.

[0106] In this configuration, the first sub-opening 1121 corresponds one-to-one with the first pad 12, and the first pad 12 is exposed through the corresponding first sub-opening 1121. As mentioned above, the back-contact solar cell can be a cell with a main grid. At least a portion of the structure of the second segment 312 of the first main grid 31 can be exposed through the second sub-opening 1122. The second sub-opening 1122 includes a first opening segment 1122a and a second opening segment 1122b, which are interconnected. Along the second direction Y, the size of the first opening segment 1122a is smaller than the size of the second opening segment 1122b, and the size of the second opening segment 1122b can be equal to the size of the first sub-opening 1121.

[0107] Along the second direction Y, the first isolation part (not shown in the figure) for achieving electrical isolation can also be disposed between the second fine grid 14 and the first main grid 31. The sidewalls on both sides of the first opening section 1122a can cover the first isolation part located between the second fine grid 14 and the first main grid 31 along the third direction Z. The sidewalls on both sides of the first opening section 1122a can also cover the end of the second fine grid 14 at the same time. The sidewalls on both sides of the second opening section 1122b can cover part of the structure of the first fine grid 13.

[0108] In some embodiments, the second opening of the third insulating layer includes a third sub-opening and a fourth sub-opening, both of which can be annular openings. The third and fourth sub-openings are alternately arranged along a first direction and are interconnected. Each third sub-opening corresponds to a second pad, with the first pad exposed from its corresponding third sub-opening. At least a portion of the fourth segment of the second main gate can be exposed from the fourth sub-opening, which includes a third opening segment and a fourth opening segment. The third and fourth opening segments are interconnected, and along a second direction, the size of the third opening segment is smaller than the size of the fourth opening segment, while the size of the fourth opening segment can be equal to the size of the third sub-opening. The third isolation portion can also be disposed between the first fine gate and the second main gate. The sidewalls on both sides of the third opening segment can cover the third isolation portion located between the first fine gate and the second main gate along a third direction, and the sidewalls on both sides of the third opening segment can also simultaneously cover the end of the first fine gate. The sidewalls on both sides of the fourth opening segment can cover a portion of the structure of the second fine gate.

[0109] In some embodiments, the aforementioned back-contact solar cell can be a multi-busbar (MBB) cell, that is, multiple first busbars and multiple second busbars are printed on the surface of the back-contact solar cell. By increasing the number of busbars, the number of fine busbars can be reduced accordingly, thereby reducing costs. At the same time, the current conduction path between the fine busbars and the main busbars can be shortened to reduce power loss and thus increase the power of the cell.

[0110] The above describes the case where the back-contact solar cell is provided with a main grid. In some embodiments of this application, the back-contact solar cell can also be a gridless cell. The case where the back-contact solar cell is a gridless cell will be described below.

[0111] like Figure 13 As shown, the back-contact solar cell 10 can also be a gridless (OBB) cell, where the solder ribbon (shown in the figure) can be directly connected to the first fine grid 13 and the second fine grid 14 to conduct current through the fine grids. Since there is no need to set up a main grid, the consumption of metal paste is reduced, thereby reducing the production cost of the back-contact solar cell 10 and the photovoltaic module.

[0112] like Figure 14As shown, in some embodiments, the first opening 112 of the first insulating layer 11 includes a plurality of first sub-openings 1121 spaced apart along the first direction X. Each first sub-opening 1121 can be an annular opening. Each first sub-opening 1121 corresponds one-to-one with a first pad 12, and the first pad 12 is exposed from its corresponding first sub-opening 1121, so that the first insulating layer 11 does not cover the first pad 12. Similarly, the second opening 181 of the third insulating layer 18 includes a plurality of third sub-openings 1811 spaced apart along the first direction X. Each third sub-opening 1811 can be an annular opening. Each third sub-opening 1811 corresponds one-to-one with a second pad 19, and the second pad 19 is exposed from its corresponding third sub-opening 1811, so that the third insulating layer 18 does not cover the second pad 19. As mentioned above, the back contact solar cell includes a first doped region and a second doped region. The first doped region includes a first sub-region and a second sub-region alternately arranged along the first direction. A plurality of first pads can be correspondingly disposed within the first sub-region. The second doped region includes a third sub-region and a fourth sub-region arranged alternately along the first direction, and the aforementioned multiple second pads can be set one-to-one within the third sub-region.

[0113] like Figure 15 As shown, in some embodiments, the first opening 112 of the first insulating layer 11 includes a first sub-opening 1121 and a second sub-opening 1122. The first sub-opening 1121 and the second sub-opening 1122 are arranged alternately along a first direction X, and there is a gap between the first sub-opening 1121 and the second sub-opening 1122, that is, the first sub-opening 1121 and the second sub-opening 1122 are not connected. The first sub-opening 1121 corresponds one-to-one with the first pad 12, and the first pad 12 is exposed from the corresponding first sub-opening 1121. At least a portion of the second sub-region of the first doped region can be exposed from the second sub-opening 1122. That is, by setting the second sub-opening 1122, the second sub-region is not completely covered by the first insulating layer 11, which helps to save the amount of the first insulating layer 11 used and reduce the production cost of the back contact solar cell.

[0114] In some embodiments, the second opening of the third insulating layer includes a third sub-opening and a fourth sub-opening, both of which can be annular openings. The third and fourth sub-openings are alternately arranged along a first direction, and there is a gap between them, meaning that the third and fourth sub-openings are not connected. Each third sub-opening corresponds one-to-one with a second pad, and the second pad is exposed from its corresponding third sub-opening. A portion of the fourth sub-region of the second doped region can be exposed from the fourth sub-opening, which helps to save on the amount of third insulating layer used and reduce the production cost of the back contact solar cell.

[0115] like Figure 16As shown, in some embodiments, the first opening 112 of the first insulating layer 11 includes a first sub-opening 1121 and a second sub-opening 1122. Both the first sub-opening 1121 and the second sub-opening 1122 are annular openings. The first sub-opening 1121 and the second sub-opening 1122 are arranged alternately along a first direction X, and the first sub-opening 1121 and the second sub-opening 1122 are interconnected. The first sub-opening 1121 corresponds one-to-one with the first pad 12, and the first pad 12 is exposed from the corresponding first sub-opening 1121. At least a portion of the second sub-region of the first doped region can be exposed from the second sub-opening 1122.

[0116] The second sub-opening 1122 includes a first opening segment 1122a and a second opening segment 1122b, which are interconnected. Along the second direction Y, the size of the first opening segment 1122a is smaller than the size of the second opening segment 1122b, and the size of the second opening segment 1122b can be equal to the size of the first sub-opening 1121. Along the second direction Y, the first isolation portion (not shown in the figure) used for electrical isolation can be disposed on the side of the second fine gate 14 facing the first pad 12. The sidewalls on both sides of the first opening segment 1122a can cover the first isolation portion along the third direction Z, and the sidewalls on both sides of the first opening segment 1122a can also simultaneously cover the ends of the second fine gate 14. The sidewalls on both sides of the second opening segment 1122b can cover part of the structure of the first fine gate 13.

[0117] In some embodiments, the second opening of the third insulating layer includes a third sub-opening and a fourth sub-opening, both of which can be annular openings. The third and fourth sub-openings are alternately arranged along a first direction and are interconnected. Each third sub-opening corresponds to a second pad, with the second pad exposed from its corresponding third sub-opening. A portion of the fourth sub-region of the second doped region can be exposed from the fourth sub-opening. The fourth sub-opening includes a third opening segment and a fourth opening segment, which are interconnected. Along a second direction, the size of the third opening segment is smaller than the size of the fourth opening segment, and the size of the fourth opening segment can be equal to the size of the third sub-opening. The sidewalls on both sides of the third opening segment can cover the third isolation portion along a third direction, and can also simultaneously cover the end of the first fine gate. The sidewalls on both sides of the fourth opening segment can cover a portion of the structure of the second fine gate.

[0118] In some embodiments, the back-contact solar cell may be provided with a plurality of first insulating layers, which may be spaced apart along a first direction. Each first insulating layer has a first opening, and a first pad is located in the corresponding first opening. Along the first direction, the size of the first insulating layer is D1, the size of the first pad is D2, and the distance between two adjacent first pads is D3. D1, D2, and D3 satisfy: D2 < D1 < D2 + D3.

[0119] exist Figures 13 to 16 In the structure of the back-contact solar cell shown, the back-contact solar cell can be a gridless solar cell, the first insulating layer 11 can cover the first isolation portion (not shown in the figure), and the third insulating layer 18 can cover the third isolation portion (not shown in the figure).

[0120] like Figure 17 As shown, this application embodiment provides a solar tandem cell 20, including a crystalline silicon bottom cell 21 and a perovskite top cell 22. The crystalline silicon bottom cell 21 includes the aforementioned back contact solar cell, and the perovskite top cell 22 is electrically connected to the crystalline silicon bottom cell 21.

[0121] The perovskite top solar cell 22 may include a substrate, a conductive thin film, an electron transport layer (e.g., titanium dioxide), a perovskite absorber layer, a hole transport layer, and a metal electrode (not shown in the figure). Perovskite materials have a high light absorption coefficient and a long carrier diffusion distance. After the photons absorbed by the perovskite material are converted into electrons, they are easily collected by the electrodes with minimal loss, thus generating high photogenerated voltage and current, resulting in high photoelectric conversion efficiency for the perovskite top solar cell 22.

[0122] By combining the aforementioned contact solar cells and perovskite solar cells into a tandem solar cell, a wider range of solar spectrum absorption can be achieved, thereby improving the photoelectric conversion efficiency of the tandem solar cell. Since the back-contact solar cell has the aforementioned technical effects, the tandem module with this back-contact solar cell also possesses the aforementioned technical effects, which will not be elaborated further here.

[0123] like Figure 18 As shown, this application embodiment provides a photovoltaic module 100, which includes a cover plate, an encapsulation layer, and a battery string 103. The battery string 103 includes a plurality of back-contact solar cells as described above, or the battery string 103 includes a plurality of solar tandem cells as described above.

[0124] The photovoltaic module 100 is equipped with a first cover plate 101 at the top and a second cover plate 106 at the bottom. A first encapsulation layer 102 is located between the first cover plate 101 and the battery string 103, and a second encapsulation layer 105 is located between the second cover plate 106 and the battery string 103. The first cover plate 101, first encapsulation layer 102, battery string 103, second encapsulation layer 105, and second cover plate 106 can be arranged along the thickness direction Z of the photovoltaic module 100 and laminated together. The first cover plate 101 can be a glass cover plate with high light transmittance. The first encapsulation layer 102 bonds the first cover plate 101 to the battery string 103, providing encapsulation and protection for the battery string 103. The material of the first encapsulation layer 102 can be one or more of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), and polyvinyl butyral (PVB). The second encapsulation layer 105 connects the battery string 103 to the second cover plate 106, and also provides encapsulation and protection for the battery string 103. The material of the second encapsulation layer 105 can be one or more of the aforementioned EVA, POE, and PVB. The material of the second cover plate 106 can be glass, or the second cover plate 106 can also be composed of multiple polymer film layers.

[0125] The above description is merely an optional embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A back-contact solar cell, characterized in that, include: First pad, and multiple first pads are arranged along a first direction; The first fine gate is connected to the first pad; The second fine grid is arranged alternately with the first fine grid along the first direction; A first insulating layer is continuously disposed along the first direction. The first insulating layer has a first opening, and a plurality of first pads are located within the first opening so that the first pads are exposed from the first insulating layer.

2. The back-contact solar cell according to claim 1, characterized in that, Along the second direction, a first isolation portion is provided between the first pad and the second fine gate, and the first insulating layer covers the first isolation portion along the third direction; The width of the first isolation part satisfies the following condition: 20μm≤W≤120μm.

3. The back-contact solar cell according to claim 2, characterized in that, The first insulating layer extends toward the direction of the second fine gate and covers the end of the second fine gate in the third direction.

4. The back-contact solar cell according to claim 2, characterized in that, The first insulating layer covers the entire structure of the second fine gate along the third direction.

5. The back-contact solar cell according to claim 2, characterized in that, The first insulating layer covers at least a portion of the structure of the first fine gate along the third direction.

6. The back-contact solar cell according to claim 5, characterized in that, The first insulating layer includes a first insulating segment that covers a portion of the structure of the first fine gate along the third direction; The dimension L1 of the first insulating segment along the second direction satisfies: 0 < L1 ≤ 600 μm.

7. The back-contact solar cell according to any one of claims 2 to 6, characterized in that, The back-contact solar cell also includes a second isolation portion and a second insulating layer; The second isolation portion is located between adjacent first and second fine gates along the first direction, and the second isolation portion is connected to the first isolation portion; The second insulating layer covers the second insulating portion along the third direction, and the second insulating layer is connected to the first insulating layer.

8. The back-contact solar cell according to claim 7, characterized in that, The back-contact solar cell includes a substrate; Along the first direction, the substrate includes a first surface and a second surface disposed opposite to each other, and the first insulating layer, the second insulating layer, the first fine gate, the second fine gate and the first pad are all disposed on the first surface; Both the first isolation portion and the second isolation portion are grooves extending from the first surface toward the second surface.

9. The back-contact solar cell according to claim 8, characterized in that, A portion of the structure of the first insulating layer extends into the first insulating portion, and / or; A portion of the structure of the second insulating layer extends into the second insulating portion.

10. The back-contact solar cell according to any one of claims 1 to 6, characterized in that, The first opening includes a plurality of first sub-openings, which are arranged at intervals along the first direction and correspond one-to-one with a plurality of first pads.

11. The back-contact solar cell according to claim 10, characterized in that, There is a gap between the outer peripheral wall of the first pad and the inner peripheral wall of the corresponding first sub-opening; Alternatively, the outer peripheral wall of the first pad is connected to the inner peripheral wall of the corresponding first sub-opening.

12. The back-contact solar cell according to claim 11, characterized in that, The back-contact solar cell includes a main grid, wherein the main grid connected to the first pad is a first main grid; The first main gate includes a first segment and a second segment arranged along the first direction. The first segment is connected to the second segment. The projection of the first segment along the third direction is located within the first pad. The first segment is connected to the first pad and is exposed from the first sub-opening. The second segment is covered by the first insulating layer, or a portion of the structure of the second segment is exposed from the first sub-opening.

13. The back-contact solar cell according to claim 10, characterized in that, The first opening further includes a second sub-opening, the first sub-opening and the second sub-opening are arranged alternately along the first direction, and the first sub-opening and the second sub-opening are spaced apart; or, the first sub-opening and the second sub-opening are connected. The back-contact solar cell includes a first sub-region and a second sub-region arranged alternately along the first direction. The first pads are disposed on the first sub-region in a one-to-one correspondence, and at least a portion of the second sub-region is exposed from the second sub-opening.

14. The back-contact solar cell according to any one of claims 1 to 6, characterized in that, The back-contact solar cell also includes a third insulating layer and a second solder pad; The second pad is connected to the second fine gate; The third insulating layer is continuously disposed along the first direction, and the third insulating layer has a second opening. A plurality of second pads are arranged along the first direction, and the plurality of second pads are all located within the second opening, so that the second pads are exposed from the third insulating layer.

15. The back-contact solar cell according to claim 14, characterized in that, Along the second direction, a third isolation portion is provided between the second pad and the first fine gate, and the third insulating layer covers the third isolation portion along the third direction.

16. A solar tandem battery, characterized in that, include: A crystalline silicon bottom cell, the crystalline silicon bottom cell comprising a back-contact solar cell according to any one of claims 1 to 15; A perovskite top cell, wherein the perovskite top cell is electrically connected to the crystalline silicon bottom cell.

17. A photovoltaic module, characterized in that, The photovoltaic module includes a cover plate, an encapsulation layer, and a battery string; The battery string comprises a plurality of back-contact solar cells as described in any one of claims 1 to 15, or the battery string comprises a plurality of solar tandem cells as described in claim 16.

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