Efficient N-type back contact solar cell, photovoltaic module and photovoltaic system

Abstract

The utility model discloses a high-efficiency N-type back contact solar cell, a photovoltaic module and a photovoltaic system, and the high-efficiency N-type back contact solar cell comprises a silicon substrate which is provided with a substrate front surface and a substrate back surface which are opposite to each other, and the substrate back surface is provided with a first doped region, an isolation region and a second doped region which are sequentially arranged; the first doped region comprises a tunneling oxide layer, a P-type polycrystalline silicon layer, an aluminum oxide layer and a back silicon nitride layer which are sequentially arranged in the direction far away from the back of the substrate; the second doped region comprises a tunneling oxide layer, an N-type polycrystalline silicon layer and a back silicon nitride layer which are sequentially arranged in the direction far away from the back of the substrate; the isolation region is provided with a back silicon nitride layer in a direction away from the back of the substrate. A contact passivation structure which is the same as the front surface of the N-TOPCon is adopted in the first doped region, and a contact passivation structure which is the same as the back surface of the N-TOPCon is adopted in the second doped region. The overall passivation level is improved, the stability and efficiency of the back contact solar cell are improved, and unnecessary material waste is avoided.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic manufacturing, specifically to high-efficiency N-type back-contact solar cells, photovoltaic modules, and photovoltaic systems. Background Technology

[0002] Back-contact solar cells are cell structures where both the positive and negative electrodes are located on the back side, with no grid lines obstructing the front. This effectively increases light absorption and short-circuit current. This design allows the cell to maximize sunlight utilization without grid obstruction, resulting in higher conversion efficiency. Because there are no metal grid lines on the front of the back-contact cell, light transmission is more direct, reducing light reflection and obstruction, thus increasing short-circuit current and open-circuit voltage. Back-contact cells also have a higher fill factor and an open-circuit voltage close to the theoretical limit, further improving cell efficiency.

[0003] For back-contact solar cells, improving the field passivation and chemical passivation effects in the P-region is crucial for reducing carrier recombination. To achieve this, conventional back-contact solar cells typically have an aluminum oxide layer deposited across the entire back side. However, since aluminum oxide has limited field passivation effects on the N-region, this approach increases costs and leads to unnecessary material waste. Utility Model Content

[0004] To address the technical problems mentioned in the prior art, this application proposes a high-efficiency N-type back-contact solar cell, photovoltaic module, and photovoltaic system.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0006] A high-efficiency N-type back-contact solar cell, comprising:

[0007] A silicon substrate having a front side and a back side opposite to each other, wherein the back side has a first doped region, an isolation region and a second doped region arranged sequentially.

[0008] The first doped region includes a tunneling oxide layer, a P-type polysilicon layer, an aluminum oxide layer, and a back silicon nitride layer sequentially disposed in the direction away from the back side of the substrate;

[0009] The second doped region includes a tunneling oxide layer, an N-type polysilicon layer, and a back silicon nitride layer sequentially disposed in the direction away from the back side of the substrate;

[0010] The isolation region has a back silicon nitride layer in the direction away from the back side of the substrate.

[0011] In some embodiments, a front-side silicon nitride layer is also included, which is located on the front side of the substrate.

[0012] In some embodiments, the thickness of the alumina layer is 2 nm to 10 nm.

[0013] In some embodiments, the isolation areas on the front and back sides of the substrate are textured.

[0014] In some embodiments, the resistivity of the silicon substrate is 0.3 Ω·cm to 3 Ω·cm.

[0015] In some embodiments, the silicon substrate is an N-type substrate.

[0016] In some embodiments, a first electrode and a second electrode are also included. The first electrode passes through the back silicon nitride layer and the alumina layer in sequence on one side of the back side of the substrate to contact the P-type polysilicon layer, and the second electrode passes through the back silicon nitride layer on one side of the back side of the substrate to contact the N-type polysilicon layer.

[0017] In some embodiments, the first electrode is made of silver-aluminum paste, and the second electrode is made of silver paste.

[0018] This application also provides a photovoltaic module, including the high-efficiency N-type back-contact solar cell as described above.

[0019] This application also provides a photovoltaic system, including the photovoltaic module as described above.

[0020] Due to the application of the above technical solution, the beneficial effects of this application compared with the prior art are as follows:

[0021] The high-efficiency N-type back-contact solar cell disclosed in this application achieves a more efficient surface passivation effect by employing different contact passivation structures in the first and second doped regions, specifically by providing an aluminum oxide layer only on the P-type polycrystalline silicon layer. Specifically, the first doped region on the back side of the substrate uses the same contact passivation structure as the front side of the N-TOPCon, while the second doped region uses the same contact passivation structure as the back side of the N-TOPCon. This design effectively improves the overall passivation level, reduces surface recombination, and enhances the photoelectric conversion efficiency of the cell. By optimizing the matching of the first and second doped regions with different contact passivation structures, the performance stability and efficiency of the back-contact solar cell are further improved, avoiding unnecessary material waste. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a cross-sectional view of the high-efficiency N-type back-contact solar cell in an embodiment of this utility model.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1-Silicon substrate; 2-Tunneling oxide layer; 3-P-type polycrystalline silicon layer; 4-Alumina layer; 5-N-type polycrystalline silicon layer; 6-Back side silicon nitride layer; 7-Front side silicon nitride layer; 8-First electrode; 9-Second electrode. Detailed Implementation

[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0027] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0028] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0029] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0030] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] Please see Figure 1 One embodiment of this application provides a high-efficiency N-type back-contact solar cell, including a silicon substrate 1. The silicon substrate 1 has a front side and a back side facing each other. The back side of the substrate has a first doped region, an isolation region, and a second doped region arranged sequentially. Notably, the front side of the substrate is the side closest to sunlight, and the back side of the substrate is the side away from sunlight.

[0033] In such Figure 1 In the illustrated embodiment, the front side of the substrate is textured, and the isolation area on the back side of the substrate also has a textured morphology. In other embodiments, the isolation area on the back side of the substrate may also be a polished surface, and this application does not specifically limit this.

[0034] In some embodiments, the silicon substrate 1 is an N-type substrate. The resistivity of the silicon substrate 1 is 0.3 Ω·cm to 3 Ω·cm.

[0035] The first doped region includes a tunneling oxide layer 2, a P-type polysilicon layer 3, an aluminum oxide layer 4, and a back silicon nitride layer 6, sequentially disposed in the direction away from the back side of the substrate. The second doped region includes a tunneling oxide layer 2, an N-type polysilicon layer 5, and a back silicon nitride layer 6, sequentially disposed in the direction away from the back side of the substrate. The isolation region has a back silicon nitride layer 6 disposed in the direction away from the back side of the substrate.

[0036] In some embodiments, a front-side silicon nitride layer 7 is also included, which is located on the front side of the substrate.

[0037] In some embodiments, a first electrode 8 and a second electrode 9 are also included. The first electrode 8 passes through the back silicon nitride layer 6 and the aluminum oxide layer 4 sequentially on one side of the back surface of the substrate to contact the P-type polysilicon layer 3. The second electrode 9 passes through the back silicon nitride layer 6 on one side of the back surface of the substrate to contact the N-type polysilicon layer 5. Specifically, the first electrode 8 is made of silver-aluminum paste, and the second electrode 9 is made of silver paste.

[0038] In some embodiments, the thickness of the alumina layer 4 is 2 nm to 10 nm. Specifically, it can be 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, or 10 nm. This application does not impose a specific limitation on this.

[0039] This application also provides a photovoltaic module, including the high-efficiency N-type back-contact solar cell as described above.

[0040] This application also provides a photovoltaic module, including the photovoltaic module described above.

[0041] Due to the application of the above technical solution, the beneficial effects of this application compared with the prior art are as follows:

[0042] The high-efficiency N-type back-contact solar cell disclosed in this application achieves a more efficient surface passivation effect by employing different contact passivation structures in the first and second doped regions, specifically by providing an aluminum oxide layer only on the P-type polycrystalline silicon layer. Specifically, the first doped region on the back side of the substrate uses the same contact passivation structure as the front side of the N-TOPCon, while the second doped region uses the same contact passivation structure as the back side of the N-TOPCon. This design effectively improves the overall passivation level, reduces surface recombination, and enhances the photoelectric conversion efficiency of the cell. By optimizing the matching of the first and second doped regions with different contact passivation structures, the performance stability and efficiency of the back-contact solar cell are further improved, avoiding unnecessary material waste.

[0043] Finally, it should be noted that the above are merely preferred embodiments of this application and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 high-efficiency N-type back-contact solar cell, characterized in that, include: A silicon substrate having a front side and a back side opposite to each other, wherein the back side has a first doped region, an isolation region and a second doped region arranged sequentially. The first doped region includes a tunneling oxide layer, a P-type polysilicon layer, an aluminum oxide layer, and a back silicon nitride layer sequentially disposed in the direction away from the back side of the substrate; The second doped region includes a tunneling oxide layer, an N-type polysilicon layer, and a back silicon nitride layer sequentially disposed in the direction away from the back side of the substrate; The isolation region has a back silicon nitride layer in the direction away from the back side of the substrate.

2. The high-efficiency N-type back-contact solar cell as described in claim 1, characterized in that, It also includes a front-side silicon nitride layer, which is located on the front side of the substrate.

3. The high-efficiency N-type back-contact solar cell as described in claim 1, characterized in that, The thickness of the alumina layer is 2 nm to 10 nm.

4. The high-efficiency N-type back-contact solar cell as described in claim 1, characterized in that, The isolation areas on the front and back sides of the substrate are textured.

5. The high-efficiency N-type back-contact solar cell as described in claim 1, characterized in that, The resistivity of the silicon substrate is 0.3 Ω·cm to 3 Ω·cm.

6. The high-efficiency N-type back-contact solar cell as described in claim 1, characterized in that, The silicon substrate is an N-type substrate.

7. The high-efficiency N-type back-contact solar cell as described in claim 1, characterized in that, It also includes a first electrode and a second electrode. The first electrode passes through the back silicon nitride layer and the alumina layer in sequence on one side of the back side of the substrate to contact the P-type polysilicon layer. The second electrode passes through the back silicon nitride layer on one side of the back side of the substrate to contact the N-type polysilicon layer.

8. The high-efficiency N-type back-contact solar cell as described in claim 7, characterized in that, The first electrode is made of silver-aluminum paste, and the second electrode is made of silver paste.

9. A photovoltaic module, characterized in that, Including the high-efficiency N-type back-contact solar cell as described in any one of claims 1 to 8.

10. A photovoltaic system, characterized in that, Including the photovoltaic module as described in claim 9.

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