Topcon cell, photovoltaic module, and tandem cell

Abstract

The present disclosure is applicable to the technical field of solar power generation, and provides a TOPCon cell, a photovoltaic module, and a tandem cell. The TOPCon cell comprises a silicon substrate, a tunneling layer, a polysilicon layer, and an aluminum oxide layer. The tunneling layer is disposed on a back surface of the silicon substrate. The polysilicon layer is disposed on a side surface of the tunneling layer away from the silicon substrate. The aluminum oxide layer is disposed on a side surface of the polysilicon layer away from the tunneling layer. The aluminum oxide layer is disposed on at least a portion of the polysilicon layer. In the above arrangement, the aluminum oxide layer is disposed on at least a portion of the polysilicon layer on the rear side of the cell, thereby enhancing the antireflective effect and improving the rear-side conversion efficiency of the cell.

Description

TOPCon cell, photovoltaic module and stacked cell

[0001] Cross-reference to related applications

[0002] The present disclosure refers to Chinese Patent Application No. 202421733622.0 entitled "TOPCon cell, photovoltaic module and stacked cell" filed on July 19, 2024, which is incorporated by reference in its entirety into the present disclosure. TECHNICAL FIELD

[0003] The present disclosure belongs to the technical field of solar power generation, and particularly relates to a TOPCon cell, a photovoltaic module and a stacked cell. BACKGROUND

[0004] A solar cell is a device that directly converts light energy into electrical energy through a photoelectric effect or a photochemical effect. The working principle of a photoelectric effect solar cell is as follows: when sunlight shines on a p-n junction of a semiconductor, new hole-electron pairs are formed. Under the action of the electric field of the p-n junction, the holes flow from the n region to the p region, and the electrons flow from the p region to the n region. When an electric circuit is connected, an electric current is formed.

[0005] The main structural components of a conventional TOPCon (Tunnel Oxide Passivated Contact) cell include an upper electrode, a passivation layer, an emitter layer, a substrate, a diffusion doped layer, a passivated contact structure, and a lower electrode. The passivated contact structure can block hole-electron recombination, thereby improving the open-circuit voltage and short-circuit current of the cell. However, the existing TOPCon cell has poor anti-reflection effect, which reduces the conversion efficiency of the cell.

[0006] Utility model content

[0007] The present disclosure provides a TOPCon cell to solve the problem of poor anti-reflection effect on the back of the existing TOPCon cell, which reduces the conversion efficiency of the cell.

[0008] The present disclosure is implemented as follows: a TOPCon cell includes:

[0009] a silicon substrate;

[0010] a tunnel layer arranged on the back of the silicon substrate;

[0011] a polysilicon layer arranged on the side of the tunnel layer away from the silicon substrate; and

[0012] an aluminum oxide layer arranged on the side of the polysilicon layer away from the tunnel layer, the aluminum oxide layer being arranged in at least part of the polysilicon layer.

[0013] In some embodiments, the back surface of the silicon substrate is provided with a diffusion doped layer, and the diffusion doped layer is provided with a tunneling layer away from the side surface of the silicon substrate.

[0014] In some embodiments, the TOPCon cell further comprises a back electrode connected with the polysilicon layer.

[0015] In some embodiments, the diffusion doped layer is arranged in a partial region of the back surface of the silicon substrate.

[0016] In some embodiments, the tunneling layer is arranged in a partial region of the diffusion doped layer.

[0017] In some embodiments, the TOPCon cell further comprises a back passivation layer arranged on the side of the aluminum oxide layer away from the polysilicon layer.

[0018] In some embodiments, the front surface of the silicon substrate is provided with an emitter layer and a front electrode connected with the emitter layer.

[0019] In some embodiments, the emitter layer is provided with a front passivation layer away from the side surface of the silicon substrate.

[0020] In some embodiments, the front passivation layer and the back passivation layer comprise at least one of silicon nitride, aluminum oxide, silicon oxynitride, and silicon oxide.

[0021] In a second aspect, the present disclosure further provides a photovoltaic module comprising the TOPCon cell as described above.

[0022] In a third aspect, the present disclosure further provides a stacked cell comprising a perovskite cell and the TOPCon cell as described above.

[0023] The present disclosure has the beneficial effect that the TOPCon cell of the present disclosure comprises a silicon substrate, a tunneling layer, a polysilicon layer, and an aluminum oxide layer, wherein the tunneling layer is arranged on the back surface of the silicon substrate, the polysilicon layer is arranged on the side of the tunneling layer away from the silicon substrate, the aluminum oxide layer is arranged on the side of the polysilicon layer away from the tunneling layer, and the aluminum oxide layer is arranged in at least a partial region of the polysilicon layer. Through the above arrangement, the aluminum oxide layer is arranged on at least a partial region of the polysilicon layer on the back surface of the cell, which increases the anti-reflection effect and improves the conversion efficiency of the back surface of the cell. BRIEF DESCRIPTION OF DRAWINGS

[0024] FIG. 1 is a structural schematic diagram of a silicon substrate of an embodiment of the TOPCon cell provided by the present disclosure;

[0025] FIG. 2 is a structural schematic diagram of a TOPCon cell provided by the present disclosure, wherein the back surface of the cell is provided with an aluminum oxide layer;

[0026] FIG. 3 is a schematic diagram of a structure of a back surface part of a TOPCon cell according to an embodiment of the present disclosure;

[0027] FIG. 4 is a schematic diagram of a structure of a TOPCon cell according to an embodiment of the present disclosure.

[0028] Main element symbol explanation: 100, silicon substrate; 110, front surface; 120, back surface; 200, tunneling layer; 300, polysilicon layer; 400, aluminum oxide layer; 500, emitter layer; 600, diffusion doping layer; 710, front surface electrode; 720, back surface electrode; 810, front surface passivation layer; 820, back surface passivation layer. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to the accompanying drawings and embodiments. The examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present disclosure, and should not be understood as a limitation on the present disclosure. In addition, it should be understood that the specific embodiments described herein are only used to explain the present disclosure and should not be used to limit the present disclosure.

[0030] In the description of the present disclosure, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be understood as a limitation on the present disclosure.

[0031] In addition, the terms "first", "second", are only for the purpose of description, and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0032] In the description of the present disclosure, it should be noted that, unless specifically defined and limited otherwise, the terms "mount", "connect", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0033] In the present disclosure, unless otherwise specifically defined and limited, "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "above" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. "Below", "below" and "below" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0034] The following disclosure provides many different embodiments or examples for implementing different structures of the present disclosure. In order to simplify the disclosure of the present disclosure, the components and arrangements of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present disclosure. In addition, the present disclosure can repeatedly refer to numerals and / or reference letters in different examples. Such repetition is for the purpose of simplification and clarity, and in itself does not indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present disclosure provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0035] The TOPCon cell of the present disclosure includes a silicon substrate, a tunneling layer, a polysilicon layer, and an aluminum oxide layer, wherein the tunneling layer is disposed on the back surface of the silicon substrate, the polysilicon layer is disposed on the side of the tunneling layer away from the silicon substrate, the aluminum oxide layer is disposed on the side of the polysilicon layer away from the tunneling layer, and the aluminum oxide layer is disposed on at least a partial region of the polysilicon layer. Through the above arrangement, the aluminum oxide layer is disposed on at least a partial region of the polysilicon layer on the back surface of the cell, which increases the anti-reflection effect and improves the conversion efficiency of the back surface of the cell.

[0036] Embodiment one

[0037] As shown in FIGS. 1-4, the embodiments of the present disclosure provide a TOPCon cell, comprising:

[0038] a silicon substrate 100;

[0039] a tunnel layer 200 disposed on the back surface 120 of the silicon substrate 100;

[0040] a polysilicon layer 300 disposed on the side of the tunnel layer 200 away from the silicon substrate 100; and

[0041] an aluminum oxide layer 400 disposed on the side of the polysilicon layer 300 away from the tunnel layer 200, the aluminum oxide layer 400 being disposed on at least a partial region of the polysilicon layer 300.

[0042] In implementation, the TOPCon cell provided by the present disclosure refers to Tunnel Oxide Passivated Contact, i.e., an oxide layer passivated contact cell.

[0043] Optionally, the TOPCon cell provided by the present disclosure refers to a single-sided TOPCon cell, i.e., a passivated contact structure composed of an ultra-thin silicon oxide layer (1 nm-2 nm) and a doped polysilicon thin film is disposed on the back surface 120 of the cell.

[0044] In implementation, the silicon substrate 100 is a silicon wafer, in some embodiments, the silicon substrate 100 is a P-type silicon wafer, and in other embodiments, the silicon substrate 100 is an N-type silicon wafer, without limitation.

[0045] In implementation, there is no essential difference between the power generation principles of a P-type silicon wafer or an N-type silicon wafer solar cell, both of which are based on PN junction for light-induced carrier separation.

[0046] Optionally, a donor impurity (such as phosphorus element and other pentavalent elements) is incorporated into a semiconductor to obtain an N-type semiconductor material; and an acceptor impurity (such as boron element and other trivalent elements) is incorporated into a semiconductor to obtain a P-type semiconductor material.

[0047] A P-type solar cell is formed by diffusing a pentavalent element, such as phosphorus element, on a P-type semiconductor material to form an n+ / p-type structure; and a N-type solar cell is formed by injecting a trivalent element, such as boron element, on an N-type semiconductor material to form a p+ / n-type structure.

[0048] Optionally, as shown in FIG. 1, the silicon substrate 100 is in the form of a wafer or a plate, having opposite front and back surfaces 110 and 120. In general, the front surface 110 of the silicon substrate 100 can be regarded as the light-receiving surface of the solar cell, and the back surface 120 of the silicon substrate 100 can be regarded as the back surface of the solar cell.

[0049] The back surface 120 of the silicon substrate 100 is sequentially provided with the tunneling layer 200, the polysilicon layer 300 and the aluminum oxide layer 400 away from the silicon substrate 100, that is, the tunneling layer 200 is arranged on the back surface 120 of the silicon substrate 100, the polysilicon layer 300 is arranged on the back surface 120 of the tunneling layer 200, and the aluminum oxide layer 400 is arranged on the back surface 120 of the polysilicon layer 300.

[0050] Optionally, the tunneling layer 200 refers to an ultra-thin tunneling oxide layer (SiO2) with a thickness of 5 nm or less, in some embodiments, 0.5 nm to 2 nm, for example, 0.5 nm, 1 nm, 1.5 nm or 2 nm, etc., which is not limited herein. The polysilicon layer 300 refers to a doped polysilicon layer, and the type of doping of the polysilicon layer 300 can be determined according to the type of the silicon substrate 100, for example, when the silicon substrate 100 is an N-type silicon wafer, the polysilicon layer 300 is a phosphorus-doped polysilicon layer.

[0051] In some optional embodiments, the aluminum oxide layer 400 is arranged on at least part of the polysilicon layer 300. In implementation, the aluminum oxide layer 400 can be arranged on the full surface of the back surface 120 of the polysilicon layer 300, as shown in FIG. 2, or can be arranged on part of the back surface 120 of the polysilicon layer 300, as shown in FIG. 3. The aluminum oxide layer 400, that is, the aluminum oxide film arranged on the back surface 120 of the polysilicon layer 300, can increase the anti-reflection effect.

[0052] The TOPCon cell of the present disclosure includes a silicon substrate 100, a tunneling layer 200, a polysilicon layer 300 and an aluminum oxide layer 400, wherein the tunneling layer 200 is arranged on the back surface 120 of the silicon substrate 100, the polysilicon layer 300 is arranged on the side of the tunneling layer 200 away from the silicon substrate 100, the aluminum oxide layer 400 is arranged on the side of the polysilicon layer 300 away from the tunneling layer 200, and the aluminum oxide layer 400 is arranged on at least part of the polysilicon layer 300. Through the above arrangement, the aluminum oxide layer 400 is arranged on at least part of the polysilicon layer 300 on the back surface 120 of the cell, thereby increasing the anti-reflection effect and improving the conversion efficiency of the back surface 120 of the cell.

[0053] In some optional embodiments, as shown in FIG. 4, the front surface 110 and the back surface 120 of the silicon substrate 100 are respectively provided with an emitter layer 500 and a diffusion-doped layer 600, wherein the emitter layer 500 is connected with the front electrode 710.

[0054] Optionally, the emitter layer 500 and the diffusion doped layer 600 refer to doped layers formed by further doping on the basis of the silicon substrate 100. For example, taking the silicon substrate 100 as an N-type silicon wafer, boron can be doped on the front surface 110 of the silicon substrate 100 to form the emitter layer 500, which can be regarded as a p+ layer, and phosphorus can be doped on the back surface 120 of the silicon substrate 100 to obtain the diffusion doped layer 600, which can be formed by diffusion alone or by diffusion of the polysilicon layer 300 into the silicon substrate 100, which is not limited herein.

[0055] By arranging the passivation contact structure on the back surface 120 of the battery, the recombination of minority carriers can be blocked, and the open-circuit voltage and short-circuit current of the battery can be improved. The super-thin tunneling layer 200 can make the majority electrons tunnel into the polysilicon layer 300 while blocking the recombination of minority carriers. The good passivation effect of the super-thin tunneling layer 200 and the polysilicon layer 300 causes the energy band of the silicon wafer surface to be bent, thereby forming a field passivation effect. The probability of electron tunneling is greatly increased, the contact resistance is reduced, the open-circuit voltage and short-circuit current of the battery are improved, and thus the conversion efficiency of the battery is improved.

[0056] In some embodiments, the diffusion doped layer 600 is arranged in a partial region of the back surface 120 of the silicon substrate 100, that is, the diffusion doped layer 600 and the silicon substrate 100 are in partial contact, thereby reducing the surface recombination in the non-contact region.

[0057] In some embodiments, the tunneling layer 200 is arranged in a partial region of the diffusion doped layer 600, that is, the tunneling layer 200 and the diffusion doped layer 600 are in partial contact, thereby effectively reducing the contact recombination.

[0058] In some embodiments, the TOPCon battery provided by the present disclosure further comprises a front passivation layer 810 and a back passivation layer 820. The front passivation layer 810 is arranged on the side of the emitter layer 500 away from the silicon substrate 100, and the back passivation layer 820 is arranged on the side of the aluminum oxide layer 400 away from the polysilicon layer 300.

[0059] The front passivation layer 810 and the back passivation layer 820 are both passivation anti-reflection films. The passivation anti-reflection film is used to improve the photoelectric conversion efficiency and stability of the solar cell, reduce the surface damage and oxidation reaction of the solar cell, and prolong the service life of the solar cell.

[0060] In implementation, the front electrode 710 is connected to the emitter layer 500 after passing through the front passivation layer 810, and the back electrode 720 is connected to the polysilicon layer 300 after passing through the back passivation layer 820.

[0061] In some embodiments, the back electrode 720 connected to the polysilicon layer 300 can be in contact with the surface of the polysilicon layer 300, or can extend into the interior of the polysilicon layer 300, but not in contact with the tunneling layer 200.

[0062] In some alternative embodiments, the back electrode 720 contacts the polysilicon layer 300 after burning through the back passivation layer 820, and part of the metal crystals of the metal paste penetrate into the polysilicon layer 300, i.e., the metal electrode is in contact with the polysilicon layer 300 and part of the metal crystals are formed in the polysilicon layer 300, but the metal crystals are not formed in the tunneling layer 200. Through the above arrangement, the metal crystals can help the carriers to move more easily to the metal electrode, thereby improving the efficiency of the solar cell.

[0063] Optionally, the front passivation layer 810 and the back passivation layer 820 include at least one of silicon nitride, aluminum oxide, silicon oxynitride, and silicon oxide, without limitation. In some embodiments, the front passivation layer 810 uses aluminum oxide, or the back passivation layer 820 can use aluminum oxide, or both the front passivation layer 810 and the back passivation layer 820 use aluminum oxide, to ensure light absorption.

[0064] Embodiment Two

[0065] In some alternative embodiments, the present disclosure provides a photovoltaic module including the TOPCon cell as described above.

[0066] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the structure and implementation principle of the photovoltaic module described above can refer to the corresponding structure and implementation principle in the aforementioned embodiment one, which will not be described here.

[0067] The TOPCon cell of the present disclosure includes a silicon substrate 100, a tunneling layer 200, a polysilicon layer 300, and an aluminum oxide layer 400, wherein the tunneling layer 200 is arranged on the back surface 120 of the silicon substrate 100, the polysilicon layer 300 is arranged on the side of the tunneling layer 200 away from the silicon substrate 100, the aluminum oxide layer 400 is arranged on the side of the polysilicon layer 300 away from the tunneling layer 200, and the aluminum oxide layer 400 is arranged in at least part of the polysilicon layer 300. Through the above arrangement, the aluminum oxide layer 400 is arranged on at least part of the polysilicon layer 300 on the back surface 120 of the cell, which increases the anti-reflection effect and improves the conversion efficiency of the back surface 120 of the cell.

[0068] Embodiment Three

[0069] In some embodiments, the present disclosure also provides a stacked cell including a perovskite cell and a TOPCon cell as described above.

[0070] In implementation, perovskite solar cells are solar cells that use perovskite-type organic metal halide semiconductors as light-absorbing materials. The laminated cell provided by the present disclosure, i.e., a perovskite-silicon-based laminated solar cell, takes advantage of the wide bandgap structure of perovskite cell materials. By placing the perovskite cell material above the silicon-based cell, it can absorb high-energy photons in the short-wave band that the silicon-based cell cannot absorb, thereby making more use of solar incident light and improving the conversion efficiency of the photovoltaic cell. It also has a higher theoretical efficiency limit, which will not be described in detail.

[0071] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the structure and implementation principle of the laminated cell described above can refer to the corresponding structure and implementation principle in the aforementioned embodiments one to two, which will not be described in detail.

[0072] The TOPCon cell of the present disclosure includes a silicon substrate 100, a tunneling layer 200, a polysilicon layer 300, and an aluminum oxide layer 400, wherein the tunneling layer 200 is disposed on the back surface 120 of the silicon substrate 100, the polysilicon layer 300 is disposed on the side of the tunneling layer 200 away from the silicon substrate 100, the aluminum oxide layer 400 is disposed on the side of the polysilicon layer 300 away from the tunneling layer 200, and the aluminum oxide layer 400 is disposed on at least part of the polysilicon layer 300. By the above arrangement, the aluminum oxide layer 400 is disposed on at least part of the polysilicon layer 300 on the back surface 120 of the cell, which increases the anti-reflection effect and improves the conversion efficiency of the back surface 120 of the cell.

[0073] The above is only a preferred embodiment of the present disclosure and does not limit the present disclosure. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A TOPCon cell, comprising: a silicon substrate; a tunneling layer disposed on a back surface of the silicon substrate; a polysilicon layer disposed on a side surface of the tunneling layer away from the silicon substrate; and an aluminum oxide layer disposed on a side surface of the polysilicon layer away from the tunneling layer, the aluminum oxide layer being disposed on at least a partial region of the polysilicon layer. A diffusion doped layer is disposed on the back surface of the silicon substrate, the diffusion doped layer being disposed on a side surface thereof away from the silicon substrate.

2. The TOPCon cell of claim 1, wherein, The TOPCon cell further comprises a back electrode connected to the polysilicon layer.

3. The TOPCon cell of any of claims 1-2, wherein, The diffusion doped layer is disposed on a partial region of the back surface of the silicon substrate.

4. The TOPCon cell of claim 2, wherein, The tunneling layer is disposed on a partial region of the diffusion doped layer.

5. The TOPCon cell of claim 2 or 4, wherein The TOPCon cell further comprises a back passivation layer disposed on a side surface of the aluminum oxide layer away from the polysilicon layer.

6. The TOPCon cell of claim 1, wherein, A front surface of the silicon substrate is provided with an emitter layer and a front electrode connected to the emitter layer.

7. The TOPCon cell of claim 6, wherein, The emitter layer is disposed on a side surface thereof away from the silicon substrate with a front passivation layer.

8. The TOPCon cell of claim 7, wherein, The front passivation layer and the back passivation layer comprise at least one of silicon nitride, aluminum oxide, silicon oxynitride, and silicon oxide.

9. The TOPCon cell of claim 8, wherein, 10.A photovoltaic module comprising the TOPCon cell of any one of claims 1 to 9. comprising a perovskite cell and the TOPCon cell of any one of claims 1 to 9.

11. A stacked battery, wherein, ​

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