TOPCon solar cell

Abstract

The embodiment of the utility model provides a TOPCon solar cell, and the solar cell comprises a silicon substrate which comprises a first surface and a second surface, and the first surface and the second surface are opposite to each other. The first tunneling layer, the first doped polycrystalline silicon layer, the first metal electrode and the first conductive wire are located on the first surface of the silicon substrate and stacked in the first direction; the first doped polycrystalline silicon layer is provided with a first fine gate electrode, the first fine gate electrode is provided with a plurality of first welding blocks at intervals, and the first welding blocks are located between the first metal electrode and the first conductive wire. According to the embodiment of the invention, a main gate electrode can be canceled, and current is collected through the first fine gate electrode and then led out through the first metal electrode, thereby reducing the transverse transmission loss of the current and improving the efficiency of the battery; the first welding block enhances the connection strength of the first conductive wire and the first metal electrode, and reduces the condition that the first conductive wire is separated from the first metal electrode in the repeated heating and cooling test process of the battery, thereby reducing the power loss of the battery.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a TOPCon solar cell. Background Art

[0002] TOPCon solar cells add a tunneling oxide layer on the back and deposit a phosphorus-doped polysilicon layer, significantly improving cell efficiency. To further improve cell efficiency, a tunneling oxide layer can also be added to the front and a boron-doped polysilicon layer can be deposited to reduce metal recombination between the silver grid lines and the boron-doped areas, further improving cell efficiency.

[0003] However, due to the severe light absorption of the polysilicon layer, TOPCon technology can only be applied to the metal-doped area on the front side, and the current loss is too high, resulting in limited improvement in cell efficiency. In addition, the current collection path of TOPCon solar cells is as follows: the photogenerated current is collected from the cell substrate to the fine grid lines, then transmitted laterally to the main grid lines through the fine grid lines, then transmitted longitudinally to the welding ribbons, and then transmitted out of the cell through the welding ribbons. It can be seen from this that the current collection path of TOPCon solar cells is complex, and due to the resistance of the main grid lines, the lateral transmission loss of current during transmission along the main grid lines is large.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Utility Model Content

[0005] The embodiments of the present application provide a TOPCon solar cell to solve or alleviate one or more of the technical problems mentioned above.

[0006] The present application provides a TOPCon solar cell, comprising:

[0007] A silicon substrate, the silicon substrate comprising a first surface and a second surface opposite to each other;

[0008] A first tunneling layer, a first doped polysilicon layer, a first metal electrode, and a first conductive filament are located on the first surface of the silicon substrate and are sequentially stacked along a first direction;

[0009] The first doped polysilicon layer has a first fine gate electrode, and a plurality of first welding blocks are arranged at intervals on the first fine gate electrode, and each of the first welding blocks is located between the first metal electrode and the first conductive wire.

[0010] Optionally, it also includes:

[0011] A first fixed block is located between the first doped polysilicon layer and the first conductive filament, and the first metal electrode is located in the first fixed block.

[0012] Optionally, the material of the first fixing block includes one of conductive glue and insulating material.

[0013] Optionally, a width of the first welding block is 30-200 μm, and a length of the first welding block is 30-3000 μm.

[0014] Optionally, the first welding blocks are evenly spaced apart.

[0015] Optionally, the width of the first conductive filament is not less than the width of the first metal electrode.

[0016] Optionally, the width of the first metal electrode is 15-200 μm.

[0017] Optionally, the material of the first metal electrode includes one of Au, Ag, Al, and Cu.

[0018] Optionally, the material of the first conductive filament includes one of Sn and Cu.

[0019] Optionally, it also includes:

[0020] A second tunneling layer, a second doped polysilicon layer, a second metal electrode, and a second conductive filament are located on the second surface of the silicon substrate and are sequentially stacked along a second direction;

[0021] The second doped polysilicon layer has a second fine gate electrode, and a plurality of second welding blocks are arranged at intervals on the second fine gate electrode, and each second welding block is located between the second metal electrode and the second conductive wire.

[0022] The above technical solution adopted in the embodiments of the present application may have the following advantages:

[0023] By completely eliminating the main gate electrode and directly connecting the first metal electrode to the first fine gate electrode, the current is collected by the first fine gate electrode and directly extracted through the first metal electrode without relying on the transmission path of the main gate electrode. This effectively reduces the loss of current due to resistance during the lateral transmission (i.e., in the direction of the main gate electrode), thereby improving the overall efficiency of the battery. In addition, by setting the first welding block, the connection strength between the first conductive filament and the first metal electrode is greatly enhanced, effectively reducing the separation of the first conductive filament from the first metal electrode during repeated temperature rise and fall reliability tests and simulated outdoor day and night temperature rise and fall, thereby reducing battery power loss and making the battery more suitable for outdoor environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0025] Figure 1 1 is a cross-sectional view of a TOPCon solar cell provided in an embodiment of the present application.

[0026] Figure 2 It is a schematic diagram of the partial structure of the TOPCon solar cell provided in an embodiment of the present application.

[0027] Figure 3 Schematic diagram of another partial structure of the TOPCon solar cell provided in an embodiment of the present application.

[0028] Description of reference numerals:

[0029] 1. Silicon substrate; 11. First tunneling layer; 12. First doped polysilicon layer; 13. First metal electrode; 14. First conductive filament; 15. First welding block; 16. First fixing block; 17. Second tunneling layer; 18. Second doped polysilicon layer; 19. Second metal electrode; 20. Second conductive filament; 21. Second welding block; 22. Second fixing block; A1, first direction; A2, second direction. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions, and advantages of this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and examples. It should be noted that the embodiments and features in the embodiments of this application can be combined with each other unless there is a conflict. This application will be described in detail below with reference to the accompanying drawings and in conjunction with the examples.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0032] Hereinafter, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. It should be noted that these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0033] like Figures 1-3 As shown, a TOPCon solar cell comprises:

[0034] A silicon substrate 1, the silicon substrate 1 comprising a first surface and a second surface arranged opposite to each other;

[0035] A first tunneling layer 11, a first doped polysilicon layer 12, a first metal electrode 13, and a first conductive filament 14 are located on the first surface of the silicon substrate 1 and are sequentially stacked along a first direction A1;

[0036] The first doped polysilicon layer 12 has a first fine gate electrode, and a plurality of first welding blocks 15 are spaced apart from each other on the first fine gate electrode. Each first welding block 15 is located between the first metal electrode 13 and the first conductive filament 14. In the embodiment of the present application, the first doped polysilicon layer 12 can be boron-doped polysilicon, the material of the first tunneling layer 11 can be silicon dioxide, and the silicon substrate 1 can be an N-type silicon substrate 1.

[0037] In this embodiment, the main gate electrode is completely eliminated, and the first metal electrode 13 is directly connected to the first fine gate electrode, so that the current is collected by the first fine gate electrode and directly extracted through the first metal electrode 13, without relying on the transmission path of the main gate electrode, effectively reducing the loss of current due to resistance during the lateral transmission (i.e., the main gate electrode direction), thereby improving the overall efficiency of the battery; in addition, by providing the first welding block 15, the connection strength between the first conductive filament 14 and the first metal electrode 13 is greatly enhanced, effectively reducing the separation of the first conductive filament 14 from the first metal electrode 13 during repeated temperature rise and fall reliability tests and simulations of outdoor day and night temperature rise and fall, thereby reducing battery power loss and making the battery more suitable for outdoor environments.

[0038] In an optional embodiment, the TOPCon solar cell further comprises:

[0039] The first fixing block 16 is located between the first doped polysilicon layer 12 and the first conductive filament 14 , and the first metal electrode 13 is located in the first fixing block 16 .

[0040] In this embodiment, the first conductive wire 14 is more stably fixed to the first metal electrode 13 by the first fixing block 16. The first fixing block 16 and the first welding block 15 work together to greatly improve the connection strength between the first conductive wire 14 and the first metal electrode 13, and reduce the possibility of the first conductive wire 14 detaching during long-term use; and the first metal electrode 13 is located in the first fixing block 16, which effectively improves the electrical connection and mechanical strength.

[0041] In an optional embodiment, the material of the first fixing block 16 includes one of a conductive adhesive and an insulating material.

[0042] In this embodiment, the material of the first fixing block 16 can be selected according to needs. When the first fixing block 16 is required to provide electrical connection, conductive glue can be selected; when the first fixing block 16 is not required to provide electrical connection, insulating material can be selected, which mainly serves as mechanical fixation.

[0043] In an optional embodiment, the width of the first welding block 15 is 30-200 μm, and the length of the first welding block 15 is 30-3000 μm.

[0044] In this embodiment, when the width of the first welding block 15 is less than 30 μm, the contact area between the first fine gate electrode and the first metal electrode 13 can be increased, thereby improving the battery current collection efficiency, but the connection strength between the first fine gate electrode and the first metal electrode 13 is relatively weak. When the width of the first welding block 15 is greater than 200 μm, the connection strength between the first fine gate electrode and the first metal electrode 13 can be effectively improved, but the battery current collection efficiency will be affected.

[0045] When the length of the first welding block 15 is less than 30 μm, the contact area between the first fine grid electrode and the first metal electrode 13 can be increased, thereby improving the battery current collection efficiency, but the connection strength between the first fine grid electrode and the first metal electrode 13 is weak. When the length of the first welding block 15 is greater than 200 μm, the connection strength between the first fine grid electrode and the first metal electrode 13 can be effectively improved, but the battery current collection efficiency will be affected.

[0046] Therefore, the width and length range of the first welding block 15 in the embodiment of the present application ensures the connection strength between the first metal electrode 13 and the first conductive wire 14 while maintaining a high collection efficiency of the battery current.

[0047] In some embodiments, the first welding block 15 at the end is 4 to 20 mm away from the edge of the battery cell. It should be noted that the edge of the battery cell is usually a relatively fragile area and is easily affected by mechanical stress. If the first welding block 15 is too close to the edge, the edge area is more susceptible to stress concentration during production, transportation or use, which may cause the generation or expansion of microcracks, or even cause the battery cell to rupture and break easily. A larger distance from the first welding block 15 to the edge of the battery cell affects the connection strength between the first metal electrode 13 and the first conductive filament 14.

[0048] In an optional embodiment, the first welding blocks 15 are evenly spaced apart. The first welding blocks 15 spaced apart can effectively improve the connection strength between the first metal electrode 13 and the first conductive wire 14.

[0049] In an optional embodiment, the width of the first conductive filament 14 is not less than the width of the first metal electrode 13 .

[0050] In this embodiment, when the width of the first conductive filament 14 is greater than or equal to the width of the first metal electrode 13, the series resistance in the current transmission path can be reduced, power loss can be reduced, and the current distribution can be made more uniform, reducing the risk of local overheating; in addition, the wider first conductive filament 14 can provide a stronger mechanical connection, which helps to improve the adhesion and stability between the first conductive filament 14 and the first metal electrode 13, reducing the risk of detachment during production and operation; at the same time, it exhibits better stress resistance when facing thermal expansion or mechanical vibration, which helps to improve the durability of the battery.

[0051] In an optional embodiment, the width of the first metal electrode 13 is 15-200 μm, for example, 15 μm, 100 μm, or 200 μm.

[0052] In an optional embodiment, the material of the first metal electrode 13 includes one of Au, Ag, Al, and Cu. All of the above are good electrode materials, among which Cu has good conductivity and low cost, and is suitable for large-scale applications.

[0053] In an optional embodiment, the material of the first conductive filament 14 includes one of Sn and Cu.

[0054] In an optional embodiment, the TOPCon solar cell further comprises:

[0055] A second tunneling layer 17, a second doped polysilicon layer 18, a second metal electrode 19, and a second conductive filament 20 are stacked sequentially along a second direction A2 on the second surface of the silicon substrate 1. The second doped polysilicon layer 18 includes a second fine gate electrode, which is interspaced with a plurality of second welding blocks 21, each located between the second metal electrode 19 and the second conductive filament 20. The second doped polysilicon layer 18 is boron-doped polysilicon. The first tunneling layer 11 can be made of silicon dioxide. The substrate also includes a second fixing block 22, which is located between the second doped polysilicon layer 18 and the second conductive filament 20, and the second metal electrode 19 is located within the second fixing block 22.

[0056] The following specific examples further illustrate the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and substance of the present invention, modifications or replacements made to the structure of the present invention are within the scope of the present invention.

[0057] Example 1

[0058] like Figure 1 As shown, a TOPCon solar cell comprises:

[0059] A silicon substrate 1, the silicon substrate 1 comprising a first surface and a second surface arranged opposite to each other;

[0060] A first tunneling layer 11, a first doped polysilicon layer 12, a first metal electrode 13, and a first conductive filament 14 are located on the first surface of the silicon substrate 1 and are sequentially stacked along a first direction A1;

[0061] a first fixing block 16 located on the first doped polysilicon layer 12 , the first fixing block 16 being located between the first doped polysilicon layer 12 and the first conductive filament 14 , and the first metal electrode 13 being located in the first fixing block 16 ;

[0062] The first doped polysilicon layer 12 has a first fine gate electrode, and a plurality of first welding blocks 15 are arranged at intervals on the first fine gate electrode, and each first welding block 15 is located between the first metal electrode 13 and the first conductive filament 14. The first doped polysilicon layer 12 can be boron-doped polysilicon, and the material of the first tunneling layer 11 can be silicon dioxide. The silicon substrate 1 can be an N-type silicon substrate 1.

[0063] A second tunneling layer 17, a second doped polysilicon layer 18, a second metal electrode 19, and a second conductive filament 20 are located on the second surface of the silicon substrate 1 and are sequentially stacked along the second direction A2;

[0064] a second fixing block 22 located on the second doped polysilicon layer 18 , the second fixing block 22 being located between the second doped polysilicon layer 18 and the second conductive filament 20 , and the second metal electrode 19 being located in the second fixing block 22 ;

[0065] The second doped polysilicon layer 18 has a second fine gate electrode, which is spaced apart by a plurality of second welding bumps 21. Each second welding bump 21 is located between the second metal electrode 19 and the second conductive filament 20. The second doped polysilicon layer 18 is boron-doped polysilicon; the material of the first tunneling layer 11 can be silicon dioxide.

[0066] Example 2

[0067] A TOPCon solar cell, comprising:

[0068] A silicon substrate 1, the silicon substrate 1 comprising a first surface and a second surface arranged opposite to each other;

[0069] A first tunneling layer 11, a first doped polysilicon layer 12, a first metal electrode 13, and a first conductive filament 14 are located on the first surface of the silicon substrate 1 and are sequentially stacked along a first direction A1;

[0070] a first fixing block 16 located on the first doped polysilicon layer 12 , the first fixing block 16 being located between the first doped polysilicon layer 12 and the first conductive filament 14 , and the first metal electrode 13 being located in the first fixing block 16 ;

[0071] The first doped polysilicon layer 12 has a first fine gate electrode, and a plurality of first welding blocks 15 are arranged at intervals on the first fine gate electrode, and each first welding block 15 is located between the first metal electrode 13 and the first conductive filament 14. The first doped polysilicon layer 12 can be boron-doped polysilicon, and the material of the first tunneling layer 11 can be silicon dioxide. The silicon substrate 1 can be an N-type silicon substrate 1.

[0072] A second tunneling layer 17, a second doped polysilicon layer 18 and a second metal electrode 19 are located on the second surface of the silicon substrate 1 and are sequentially stacked along the second direction A2;

[0073] The second doped polysilicon layer 18 has fine gate lines and main gate lines, and the main gate lines are electrically connected to the second metal electrode 19 . The second doped polysilicon layer 18 is boron-doped polysilicon. The material of the first tunneling layer 11 can be silicon dioxide.

[0074] In order to more clearly illustrate the technical effects of the embodiments of the present application, the present application also provides a comparative example 1. The structure of the TOPCon solar cell of comparative example 1 is similar to the structure of the TOPCon solar cell of embodiment 1, and the only difference is that both the first doped polysilicon layer 12 and the second doped polysilicon layer 18 have fine grid lines and main grid lines.

[0075] The TOPCon solar cells of Examples 1 to 2 of the present application and Comparative Example 1 were prepared into corresponding solar cell modules, and the performance of the corresponding solar cell modules was tested to obtain the short-circuit current density Jsc, open-circuit voltage Voc, fill factor FF, and photoelectric conversion efficiency PCE of the corresponding solar cell modules. The test results are shown in Table 1.

[0076] Table 1

[0077]

[0078] It can be seen from the data in Table 1 that compared with the solar cell assembly of Comparative Example 1, the photoelectric conversion efficiency of the solar cell assemblies of Examples 1 to 2 of the present application is improved. This is because the main grid electrode is completely eliminated in the preparation of TOPCon solar cells in Examples 1 and 2 of the present application, and the first metal electrode is directly connected to the first fine grid electrode, so that the current is collected by the first fine grid electrode and directly derived through the first metal electrode without relying on the transmission path of the main grid electrode, which effectively reduces the loss caused by resistance during the lateral transmission of current (i.e., in the direction of the main grid electrode), thereby improving the overall efficiency of the battery.

[0079] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0080] For ease of description, the directions or positional relationships indicated by directional terms such as "front, back, up, down, left, right," "lateral, vertical, perpendicular, horizontal," and "top, bottom" are generally based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional terms do not indicate or imply that the devices or components referred to must have a specific direction or be constructed and operated in a specific direction, and therefore should not be understood as limiting the scope of protection of this application. The directional terms "inside" and "outside" refer to the inside and outside relative to the outline of the components themselves. For example, if the device in the drawings is inverted, the device described as "above" or "on top of other devices or structures" will be positioned as "below" or "below" the other devices or structures. Therefore, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein should be interpreted accordingly.

[0081] Unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0082] Unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0083] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0084] It should also be noted that references to "one embodiment," "another embodiment," "an embodiment," and the like throughout this specification refer to specific features, structures, or characteristics described in conjunction with that embodiment as included in at least one embodiment generally described herein. The appearance of the same expression in multiple places in this specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in conjunction with any embodiment, it is intended that such feature, structure, or characteristic, when implemented in conjunction with other embodiments, also fall within the scope of this application.

[0085] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0086] It should also be noted that the above are only preferred embodiments of the present application and do not limit the scope of patent protection of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the scope of patent protection of the present application.

Claims

1. A TOPCon solar cell, characterized in that: include: A silicon substrate (1), the silicon substrate (1) comprising a first surface and a second surface arranged opposite to each other; A first tunneling layer (11), a first doped polysilicon layer (12), a first metal electrode (13), and a first conductive filament (14) are located on the first surface of the silicon substrate (1) and are sequentially stacked along a first direction (A1); The first doped polysilicon layer (12) has a first fine gate electrode, the first fine gate electrode is provided with a plurality of first welding blocks (15) at intervals, and each first welding block (15) is located between the first metal electrode (13) and the first conductive wire (14).

2. The TOPCon solar cell according to claim 1, characterized in that Also includes: A first fixed block (16) is located between the first doped polysilicon layer (12) and the first conductive wire (14), and the first metal electrode (13) is located in the first fixed block (16).

3. The TOPCon solar cell according to claim 2, characterized in that The material of the first fixing block (16) includes one of conductive glue and insulating material.

4. The TOPCon solar cell according to claim 1, characterized in that The width of the first welding block (15) is 30-200 μm, and the length of the first welding block (15) is 30-3000 μm.

5. The TOPCon solar cell according to claim 1, characterized in that The first welding blocks (15) are evenly spaced.

6. The TOPCon solar cell according to claim 1, characterized in that The width of the first conductive wire (14) is not less than the width of the first metal electrode (13).

7. The TOPCon solar cell according to claim 1, characterized in that The width of the first metal electrode (13) is 15-200 μm.

8. The TOPCon solar cell according to claim 1, characterized in that The material of the first metal electrode (13) includes one of Au, Ag, Al and Cu.

9. The TOPCon solar cell according to claim 1, characterized in that The material of the first conductive wire (14) includes one of Sn and Cu.

10. The TOPCon solar cell according to claim 1, characterized in that Also includes: A second tunneling layer (17), a second doped polysilicon layer (18), a second metal electrode (19), and a second conductive filament (20) are located on the second surface of the silicon substrate (1) and are sequentially stacked along a second direction (A2); The second doped polysilicon layer (18) has a second fine gate electrode, the second fine gate electrode is provided with a plurality of second welding blocks (21) at intervals, and each second welding block (21) is located between the second metal electrode (19) and the second conductive wire (20).

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