Photovoltaic cell, photovoltaic module and photovoltaic system
By using boron doped polysilicon layer or microcrystalline silicon layer combined with an intrinsic amorphous silicon layer in TOPCon cells, the emission passivation structure of the intrinsic amorphous silicon layer is replaced by the traditional boron diffusion layer and laser selective heavy doping process, the difficulty of boron diffusion and laser selectivity are solved. The problem of heavy doping to damage the battery substrate has improved the passivation effect and electrical performance of the front of the battery.
Patent Information
- Application Number
- CN202420666925.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-02
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2034-04-02
AI Technical Summary
The existing TOPCon batteries are difficult to operate in the boron diffusion process, resulting in uneven PN junctions, and the laser selective heavy doping process has a great damage to the battery substrate, and the front passivation effect is poor.
Use boron doped polycrystalline silicon layer or boron doped microcrystalline silicon layer combined with an intrinsic amorphous silicon layer as the emission passivation structure, replace the traditional boron diffusion layer, and prepare it through plasma enhanced chemical vapor deposition to avoid laser selective heavy doping steps, and A plurality of passivation layers are provided on the front of the silicon substrate to improve the passivation effect.
The problems of boron diffusion difficulties and laser selective heavy doping are solved, which improves the passivation effect on the front of the battery cell and the electrical performance of the emission passivation structure, and reduces electrical transmission loss.
Smart Images
Figure CN222168403U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of solar cells, in particular to a photovoltaic cell, a photovoltaic component and a photovoltaic system. Background Art
[0002] TOPCon cells are solar cells that use an ultra-thin oxide layer as a passivation layer. Existing TOPCon cells generally require the diffusion of boron elements on the positive surface of an N-type silicon substrate to achieve the purpose of forming a PN junction. This type of TOPCon cell has mature mass production technology and is the mainstream TOPCon cell structure in the industry.
[0003] However, this type of TOPCon battery still has several shortcomings. First, the existing boron diffusion process is difficult to operate. During the diffusion process of the boron element, the diffused boron source is introduced into the diffusion equipment by gas-carrying source. The diffused boron source is easily unevenly distributed on the front surface of the N-type silicon substrate, resulting in an uneven PN junction. Moreover, it is also very difficult to diffuse boron on the silicon substrate, and it is difficult for the boron element to diffuse into the silicon substrate. Second, the front PN junction preparation technology of this type of TOPCon battery, in addition to the need to pass the boron source on the front surface of the N-type silicon substrate to achieve diffusion, also requires a subsequent laser re-doping step to diffuse the boron element into the silicon substrate by laser to form a selective emitter. However, the laser selective re-doping process causes great damage to the substrate of the battery cell. In addition, the passivation effect of this type of TOPCon battery is mainly concentrated on the back of the N-type silicon substrate, and the front passivation effect of the battery is not good enough. Utility Model Content
[0004] The utility model aims to provide a photovoltaic cell and a photovoltaic module and a photovoltaic system including the same, so as to solve the problems of difficult boron diffusion and serious damage to the cell substrate caused by laser selective re-doping in the existing TOPCon cell preparation process.
[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0006] A photovoltaic cell comprises a silicon substrate, an emission passivation structure arranged on the front side of the silicon substrate, a tunneling electric field passivation structure arranged on the back side of the silicon substrate, and an electrode assembly, wherein:
[0007] The emission passivation structure is provided with an intrinsic amorphous silicon layer, a boron-doped amorphous silicon layer, a boron-doped polycrystalline silicon layer or a boron-doped microcrystalline silicon layer, and a front passivation layer, wherein the intrinsic amorphous silicon layer is provided on the front side of the silicon substrate;
[0008] The electrode assembly comprises a first electrode and a second electrode, wherein the first electrode is connected to the emission passivation structure, and the second electrode is connected to the tunneling electric field passivation structure.
[0009] In some embodiments, the tunneling electric field passivation structure includes a tunneling oxide layer, a heavily doped polysilicon layer, and a back silicon nitride layer, and the tunneling oxide layer is disposed on the back side of the silicon substrate.
[0010] In some embodiments, the front passivation layer includes an aluminum oxide layer, and the aluminum oxide layer is disposed on the front side of the boron-doped polysilicon layer or the boron-doped microcrystalline silicon layer.
[0011] In some embodiments, the front passivation layer further includes a silicon nitride layer or a silicon oxide layer, and the silicon nitride layer or the silicon oxide layer is disposed on the front side of the aluminum oxide layer.
[0012] In some embodiments, there are multiple first electrodes, which are spaced apart along the length direction of the silicon substrate; there are multiple second electrodes, which are spaced apart along the length direction of the silicon substrate.
[0013] In some embodiments, one end of the first electrode is disposed in the boron-doped polysilicon layer or the boron-doped microcrystalline silicon layer, or one end of the first electrode is disposed at the junction of the boron-doped polysilicon layer or the boron-doped microcrystalline silicon layer and the boron-doped amorphous silicon layer.
[0014] In some embodiments, the first electrode and the second electrode are silver electrodes.
[0015] In some embodiments, the silicon substrate is an N-type silicon substrate.
[0016] Based on the aforementioned photovoltaic cell, the utility model further provides a photovoltaic assembly, which includes the aforementioned photovoltaic cell.
[0017] Based on the aforementioned photovoltaic assembly, the utility model further provides a photovoltaic system, which includes the aforementioned photovoltaic assembly.
[0018] Compared with the prior art, the photovoltaic cell and the photovoltaic module and photovoltaic system comprising the photovoltaic cell according to the embodiment of the utility model have the following beneficial effects:
[0019] (1) The photovoltaic cell replaces the boron diffusion layer set on the front side of the silicon substrate of the existing TOPCon cell by setting a boron-doped polycrystalline silicon layer or a boron-doped microcrystalline silicon layer in combination with a boron-doped amorphous silicon layer, so that the preparation process of the photovoltaic cell does not need to go through the laser selective re-doping step, thereby fundamentally solving the problem of difficult boron diffusion in TOPCon cells and serious damage to the cell substrate caused by poor control of laser selective re-doping;
[0020] (2) The photovoltaic cell forms a plurality of passivation structures such as an intrinsic amorphous silicon layer and a front passivation layer on the front of the silicon substrate by arranging an intrinsic amorphous silicon layer on the front of the silicon substrate, thereby effectively improving the passivation effect on the front of the cell and reducing the electrical loss of the cell during power generation;
[0021] (3) By providing a boron-doped polysilicon layer, the photovoltaic cell improves the conductivity of the emission passivation structure of the photovoltaic cell, effectively improves the electrical performance of the emission passivation structure, and reduces the electrical transmission loss of the emission passivation structure. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 is a schematic diagram of a photovoltaic cell in Example 1 of the utility model;
[0023] Figure 2 It is a schematic diagram of the photovoltaic cell in Example 2 of the utility model.
[0024] In the figure, 1. silicon substrate; 2. emission passivation structure; 20. intrinsic amorphous silicon layer; 21. boron-doped amorphous silicon layer; 22a. boron-doped polysilicon layer; 22b. boron-doped microcrystalline silicon layer; 23. front passivation layer; 230. aluminum oxide layer; 231a. front silicon nitride layer; 231b. silicon oxide layer; 3. tunneling electric field passivation structure; 30. tunneling oxide layer; 31. heavily doped polysilicon layer; 32. back silicon nitride layer; 4. first electrode; 5. second electrode. DETAILED DESCRIPTION
[0025] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0026] In the description of the present utility model, it should be understood that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. The terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.
[0027] In the description of the present invention, it should be understood that the terms "height", "up", "down", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used in the present invention to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0028] In the description of the present invention, it should be understood that the terms "first" and "second" are used in the present invention for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.
[0029] Example 1
[0030] like Figure 1 As shown, a photovoltaic cell preferably implemented in the utility model comprises a silicon substrate 1, an emission passivation structure 2 arranged on the front side of the silicon substrate 1, a tunneling electric field passivation structure 3 arranged on the back side of the silicon substrate 1, and an electrode assembly, wherein:
[0031] The emission passivation structure 2 is provided with an intrinsic amorphous silicon layer 20, a boron-doped amorphous silicon layer 21, a boron-doped polysilicon layer 22a, and a front passivation layer 23. The intrinsic amorphous silicon layer 20 is provided on the front side of the silicon substrate 1;
[0032] The front passivation layer 23 includes an aluminum oxide layer 230 and a front silicon nitride layer 231a. The aluminum oxide layer 230 is disposed on the front side of the boron-doped polysilicon layer 22a, and the front silicon nitride layer 231a is disposed on the front side of the aluminum oxide layer 230.
[0033] The tunneling electric field passivation structure 3 includes a tunneling oxide layer 30, a heavily doped polysilicon layer 31, and a back silicon nitride layer 32, wherein the tunneling oxide layer 30 is disposed on the back of the silicon substrate 1;
[0034] The electrode assembly includes a first electrode 4 and a second electrode 5 . The first electrode 4 is connected to the emission passivation structure 2 , and the second electrode 5 is connected to the tunneling electric field passivation structure 3 .
[0035] It should be noted that the front side and the back side of the silicon substrate 1 are two opposite end surfaces, and the intrinsic amorphous silicon layer 20 and the tunneling oxide layer 30 are respectively arranged at two opposite ends of the silicon substrate 1 .
[0036] Based on the above scheme, the boron-doped polycrystalline silicon layer 22a of the photovoltaic cell of the present embodiment 1 cooperates with the boron-doped amorphous silicon layer 21 to replace the boron diffusion layer provided on the front side of the silicon substrate 1 of the existing TOPCon cell, so that the photovoltaic cell of the present embodiment 1 does not need to undergo the conventional boron diffusion process during the preparation process, which solves the problem of difficult boron diffusion in the preparation process of the existing photovoltaic cells. Moreover, the preparation of the boron-doped amorphous silicon layer 21 can be completed in terms of process by plasma enhanced chemical vapor deposition, which can freely adjust the doping concentration by changing the gas flow ratio to achieve in-situ doping of silane and boron sources. The preparation of the boron-doped amorphous silicon layer 21, the boron-doped polycrystalline silicon layer 22a or the doped microcrystalline silicon layer 22b does not require high-power laser selective re-doping, which solves the problem of severe damage to the cell substrate caused by laser selective re-doping in the preparation process of the existing photovoltaic cells.
[0037] In addition, the photovoltaic cell of this embodiment 1 optimizes the performance of the front structural layer of the silicon substrate 1 by setting the intrinsic amorphous silicon layer 20 and the boron-doped polycrystalline silicon layer 22a on the front side of the silicon substrate 1. For example, by setting the intrinsic amorphous silicon layer 20 on the front side of the silicon substrate 1, multiple passivation structures including the intrinsic amorphous silicon layer 20 and the front passivation layer 23 are formed on the front side of the silicon substrate 1, which effectively improves the passivation effect of the front side of the cell and reduces the electrical loss of the cell during the power generation process; by setting the boron-doped polycrystalline silicon layer 22a, the conductivity of the emission passivation structure 2 is improved, the electrical performance of the emission passivation structure 2 is effectively improved, and the electrical transmission loss of the emission passivation structure 2 is reduced.
[0038] In this embodiment 1, the silicon substrate 1 is an N-type silicon substrate 1, which is coupled with the boron-doped polysilicon layer 22a and the boron-doped amorphous silicon layer 21 to generate a PN junction. Under the same doping concentration, the minority carrier lifetime of the N-type silicon substrate 1 is much higher than that of the P-type silicon substrate 1, so that the N-type silicon substrate 1 has the advantages of high minority carrier lifetime and low light-induced degradation. At the same time, the N-type silicon substrate 1 has a greater tolerance to metal impurities. Therefore, the photovoltaic cell of this embodiment 1 is preferably prepared using the N-type silicon substrate 1.
[0039] In this embodiment 1, there are multiple first electrodes 4, which are arranged at intervals along the length direction of the silicon substrate 1, and one end of the first electrode 4 is arranged in the boron-doped polysilicon layer 22a, or one end of the first electrode 4 is arranged at the junction of the boron-doped polysilicon layer 22a and the boron-doped amorphous silicon layer 21, so as to ensure the conductive connection between the first electrode 4 and the emission passivation structure 2; there are multiple second electrodes 5, which are arranged at intervals along the length direction of the silicon substrate 1, and one end of the second electrode 5 is arranged in the heavily doped polysilicon layer 31. By arranging multiple first electrodes 4 and multiple second electrodes 5, the photovoltaic cell can be connected to a load or other closed circuit when preparing a photovoltaic module or a photovoltaic system.
[0040] The first electrode 4 and the second electrode 5 may be silver electrodes. In other embodiments, according to the specifications and performance requirements of the photovoltaic cell design, the first electrode 4 and the second electrode 5 may also be made of other materials for conductive connection.
[0041] Based on the aforementioned photovoltaic cell, this embodiment 1 also provides a photovoltaic module, which includes the aforementioned photovoltaic cell. The number of photovoltaic cells can be multiple, and the photovoltaic module can be packaged by connecting two or more photovoltaic cells in series and / or in parallel. In practical applications, the photovoltaic module can be fixed in the corresponding structural member through the structural member for fixing the photovoltaic cell, so that the photovoltaic cell of this embodiment 1 is connected in parallel or in series.
[0042] In addition, based on the aforementioned photovoltaic cell, this embodiment 1 also provides a photovoltaic system, which includes the aforementioned photovoltaic module. The photovoltaic system can be formed by connecting one or more of the above photovoltaic modules in series and / or in parallel, so that the photovoltaic system includes multiple photovoltaic cells of this embodiment 1. In practical applications, by increasing the number of photovoltaic modules, the area of the photovoltaic system can be increased by connecting them in series and / or in parallel.
[0043] Example 2
[0044] like Figure 2 As shown, the difference between this embodiment 2 and embodiment 1 lies in the difference in the structural layers of the emission passivation structure 2, wherein:
[0045] In this embodiment 2, in the emission passivation structure 2, a boron-doped microcrystalline silicon layer 22b is provided between the boron-doped amorphous silicon layer 21 and the front passivation layer 23, so that the emission passivation structure 2 of the photovoltaic cell of this embodiment 2 includes an intrinsic amorphous silicon layer 20, a boron-doped amorphous silicon layer 21, a boron-doped microcrystalline silicon layer 22b, and a front passivation layer 23, and the intrinsic amorphous silicon layer 20 is provided on the front side of the silicon substrate 1;
[0046] In the front passivation layer 23, the front side of the aluminum oxide layer 230 is the silicon oxide layer 231b, so that the front passivation layer 23 of the photovoltaic cell of this embodiment 2 includes the aluminum oxide layer 230 and the silicon oxide layer 231b, the aluminum oxide layer 230 is connected to the boron-doped microcrystalline silicon layer 22b, and the silicon nitride layer is arranged on the front side of the aluminum oxide layer 230.
[0047] Based on the structural layer differences of the emission passivation structure 2, in this embodiment 2, one end of the first electrode 4 is arranged in the boron-doped microcrystalline silicon layer 22b, or one end of the first electrode 4 is arranged at the junction of the boron-doped microcrystalline silicon layer 22b and the boron-doped amorphous silicon layer 21 to ensure the conductive connection between the first electrode 4 and the emission passivation structure 2.
[0048] According to the design requirements of the photovoltaic cell performance, the photovoltaic cell can selectively arrange a boron-doped microcrystalline silicon layer 22b or a boron-doped polycrystalline silicon layer 22a, a silicon nitride layer or a silicon oxide layer 231b to adjust the front passivation and electrical transmission effects of the photovoltaic cell.
[0049] In summary, the embodiments of the utility model provide a photovoltaic cell, a photovoltaic module, and a photovoltaic system. The photovoltaic cell replaces the boron diffusion layer of the existing TOPCon cell on the front side of the silicon substrate 1 by setting a boron-doped polycrystalline silicon layer 22a or a boron-doped microcrystalline silicon layer 22b, in combination with a boron-doped amorphous silicon layer 21, so that the preparation process of the photovoltaic cell does not need to undergo a laser selective re-doping step, thereby fundamentally solving the problem that the boron diffusion of the TOPCon cell is difficult and the laser selective re-doping is not well controlled, and the laser will cause great damage to the cell substrate. Moreover, the photovoltaic cell forms multiple passivation structures such as the intrinsic amorphous silicon layer 20 and the front passivation layer 23 on the front side of the silicon substrate 1 by setting an intrinsic amorphous silicon layer 20 on the front side of the silicon substrate 1, thereby effectively improving the passivation effect of the front side of the cell and reducing the electrical loss of the cell during the power generation process. In addition, the photovoltaic cell improves the conductivity of the emission passivation structure 2 by setting the boron-doped polycrystalline silicon layer 22a, effectively improves the electrical performance of the emission passivation structure 2, and reduces the electrical transmission loss of the emission passivation structure 2.
[0050] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.
Claims
1. A photovoltaic cell, characterized in that: The invention comprises a silicon substrate, an emission passivation structure arranged on the front side of the silicon substrate, a tunneling electric field passivation structure arranged on the back side of the silicon substrate, and an electrode assembly, wherein: The emission passivation structure is provided with an intrinsic amorphous silicon layer, a boron-doped amorphous silicon layer, a boron-doped polycrystalline silicon layer or a boron-doped microcrystalline silicon layer, and a front passivation layer, wherein the intrinsic amorphous silicon layer is provided on the front side of the silicon substrate; The electrode assembly includes a first electrode and a second electrode, the first electrode is connected to the emission passivation structure, and the second electrode is connected to the tunneling electric field passivation structure.
2. The photovoltaic cell according to claim 1, characterized in that: The tunneling electric field passivation structure comprises a tunneling oxide layer, a heavily doped polysilicon layer, and a back silicon nitride layer. The tunneling oxide layer is arranged on the back side of the silicon substrate.
3. The photovoltaic cell according to claim 1, characterized in that: The front passivation layer includes an aluminum oxide layer, and the aluminum oxide layer is disposed on the front side of the boron-doped polysilicon layer or the boron-doped microcrystalline silicon layer.
4. The photovoltaic cell according to claim 3, characterized in that: The front passivation layer further includes a silicon nitride layer or a silicon oxide layer, and the silicon nitride layer or the silicon oxide layer is disposed on the front side of the aluminum oxide layer.
5. The photovoltaic cell according to claim 1, characterized in that: There are multiple first electrodes, which are spaced apart along the length direction of the silicon substrate; there are multiple second electrodes, which are spaced apart along the length direction of the silicon substrate.
6. The photovoltaic cell according to claim 1, characterized in that: One end of the first electrode is disposed in the boron-doped polycrystalline silicon layer or the boron-doped microcrystalline silicon layer, or, One end of the first electrode is disposed at a junction of the boron-doped polycrystalline silicon layer or the boron-doped microcrystalline silicon layer and the boron-doped amorphous silicon layer.
7. The photovoltaic cell according to claim 1, characterized in that: The first electrode and the second electrode are both silver electrodes.
8. The photovoltaic cell according to claim 1, characterized in that: The silicon substrate is an N-type silicon substrate.
9. A photovoltaic module, characterized in that: The photovoltaic cell comprises the photovoltaic cell according to any one of claims 1 to 8.
10. A photovoltaic system, characterized in that: Comprising the photovoltaic module described in claim 9.