TOPCon battery structure, photovoltaic module and system

Abstract

The utility model discloses a TOPCon battery structure, a photovoltaic module and a system. The battery structure comprises a silicon wafer body; front and back surface structural layers; and front and back metal electrodes. According to the utility model, on one hand, electron collection and conduction can be well realized through introduction of the isolation conductive film layer, a back surface field passivation effect can be further enhanced, aluminum paste is used for printing, invasion of aluminum paste is blocked through the isolation conductive film layer, damage of the aluminum paste to the silicon substrate is reduced, and great reduction of open-circuit voltage (Voc) is avoided; good contact with an electrode is also realized; and on the other hand, the silver paste is replaced by the aluminum paste, the production cost is reduced, the efficiency of the solar cell is greatly improved, and the requirements of the market for efficient and low-cost solar cells are met.

Description

Technical Field

[0001] The utility model belongs to the technical field of solar cells, and specifically relates to a TOPCon cell structure, and also relates to a photovoltaic component and a photovoltaic system. Background Art

[0002] Crystalline silicon solar cells with TOPCon cell structures have the advantages of high efficiency and stable performance. They are gradually replacing PERC cells in the photovoltaic market and occupying a dominant position. At the same time, further cost reduction and further improvement of efficiency will be the focus of future development of crystalline silicon photovoltaic technology. At present, the back structure of TOPCon cell structures is almost 100% printed silver paste electrode in the industry. Therefore, there are the following technical defects:

[0003] 1) Silver paste costs account for about 42% of non-silicon production costs. With the increase in the market share of TOPCon batteries in recent years, the demand for silver has increased, but there has always been a large gap in supply, which has led to a tight supply-demand relationship. At the same time, the price of silver has gradually climbed to 7,000rmb / kg, which has led to high silver paste costs. Therefore, how to reduce the cost of metallization paste has gradually become a research hotspot in the photovoltaic field and has become more and more urgent.

[0004] 2) In order to reduce costs, many manufacturers want to use aluminum paste instead of silver paste, because the price of aluminum is much lower than that of silver. The price of aluminum paste is only 100-200rmb / kg, and the resource volume and output of aluminum are larger, so there is no need to worry about supply problems. However, there are certain technical difficulties in using aluminum paste instead of silver paste and applying it on the back of the battery: the back of the TOPCon battery uses tunneling silicon oxide superimposed on heavily doped passivated polysilicon structure to achieve back field passivation and carrier transport. When the aluminum paste contacts the polysilicon, the low-melting-point aluminum will diffuse with the polysilicon, resulting in the destruction of the polysilicon, and easily forming aluminum spikes (spikes of aluminum-silicon alloy inserted into the tunneling layer), causing a sharp deterioration of passivation and a sharp increase in the damage to the metal contact area, resulting in a significant decrease in the open circuit voltage (Voc). This phenomenon will become more serious with the increase of the doping concentration of polysilicon. Therefore, there are great technical difficulties in using aluminum paste instead of silver paste. Utility Model Content

[0005] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide an improved TOPCon battery structure.

[0006] At the same time, the utility model also relates to a photovoltaic component and a photovoltaic system.

[0007] In order to solve the above technical problems, the technical solutions adopted by the utility model are as follows:

[0008] A TOPCon battery structure includes a silicon wafer body, a front structural layer, a back structural layer, a front metal electrode and a back metal electrode. In particular, the back structural layer includes a tunneling oxide layer, a polysilicon layer, an isolation conductive film layer and a back passivation layer, which are formed on the back of the silicon wafer body from the inside to the outside, wherein the isolation conductive film layer fully covers the back of the polysilicon layer, the back passivation layer forms a groove at the corresponding metal area, and the portion of the isolation conductive film layer corresponding to the groove is exposed to form an electrode contact surface, and the back metal electrode is an aluminum electrode, and the aluminum electrode fills the groove and contacts with the electrode contact surface.

[0009] Preferably, the isolating conductive film layer is a magnesium oxide film layer, a titanium dioxide film layer or an aluminum-doped zinc oxide film layer; and / or, when the isolating conductive film layer is an aluminum-doped zinc oxide film layer, the thickness is 30-100nm; when the isolating conductive film layer is a magnesium oxide film layer or a titanium dioxide film layer, the thickness is 5-10nm. In short, a new isolating conductive film layer is added outside the back polysilicon layer. The introduction of this layer can well realize electron collection and conduction, and the TiO2 / MgO / AZO film can also bring further enhancement of the back field passivation effect. At the same time, this battery is printed with aluminum paste, and the intrusion of aluminum paste is blocked by the isolating conductive film layer, which reduces the damage of aluminum paste to the silicon substrate, and at the same time achieves good contact with the electrode, so as to achieve the application of aluminum paste. In addition, AZO can be replaced by zinc oxide materials doped with elements including but not limited to manganese, titanium, and magnesium.

[0010] According to a specific implementation and preferred aspect of the utility model, the width of the metal area is greater than the width of the slot, and the aluminum electrode is formed on the back passivation layer corresponding to the metal area from the portion exposed in the slot, thereby ensuring good contact between the isolation conductive film layer and the electrode and reducing the metal contact resistance.

[0011] Preferably, the width of the metal paste electrode grid lines of the aluminum electrode is 80-120 μm, and the width of the groove is 30-35 μm; and / or the aluminum electrodes are symmetrically distributed about the center line of the groove.

[0012] Furthermore, the grooves are evenly spaced and distributed on the back side of the back passivation layer; the aluminum electrodes correspond to the grooves one by one.

[0013] In short, after printing the main grid on the back, use a laser to open holes in the cover layer. Specifically, use a green light with a wavelength of 532nm, a power of 14-20W, and a frequency of about 2.0-3.0MHz as a laser source for intermittent irradiation, and open holes at equal intervals. The line width of the opening is 30-35μm to ensure good contact between the isolated conductive film layer and the electrode. Then use screen printing technology to print equidistant aluminum paste electrode grid lines in the laser opening area and perform high-temperature sintering. Specifically, the width of the metal paste electrode grid line is 80-120μm. Since the resistivity of aluminum is slightly higher than that of silver and the opening needs to be filled, the width of the electrode should be slightly wider than the opening to reduce the metal contact resistance.

[0014] In some specific embodiments, the silicon wafer body is an N-type single crystal silicon substrate; and / or the resistivity of the silicon wafer body is 0.5 to 3 Ω·cm, and the thickness is 100 to 200 μm.

[0015] In some embodiments, the tunnel oxide layer is SiO x layer, and the thickness is about 0.8~1.2nm.

[0016] In some specific embodiments, the polysilicon layer is an n+poly-Si layer and has a thickness of about 110-135 nm.

[0017] In some embodiments, the back passivation layer is SiN x layer, with a refractive index of 1.9 to 2.3 and a thickness of 70 to 100 nm.

[0018] According to another specific implementation and preferred aspect of the present invention, the front side of the silicon wafer body is velvet, and the front side structure layer includes a boron-doped emitter, AlO x A front metal electrode is formed on a surface of the front passivation layer.

[0019] Another technical solution of the utility model is: a photovoltaic module, which includes a front packaging layer, a photovoltaic cell, and a back packaging layer, wherein the photovoltaic cell is the above-mentioned TOPCon cell structure.

[0020] Another technical solution of the utility model is: a photovoltaic system, which includes the above-mentioned photovoltaic module, wherein there are one or more photovoltaic modules, and when there are multiple photovoltaic modules, the multiple photovoltaic modules are connected. In short, the multiple photovoltaic modules are connected (connected in series).

[0021] Due to the implementation of the above technical solution, the utility model has the following advantages compared with the prior art:

[0022] In the existing TOPCon battery structure, the cost of silver paste used in electrodes accounts for about 42% of the non-silicon production cost. With the increase in the market share of TOPCon batteries in recent years, the demand for silver has increased, but there has always been a large gap in supply, which has led to a tight supply-demand relationship; at the same time, the price of silver has gradually climbed to 7000rmb / kg, which has led to high silver paste costs. Therefore, how to reduce the cost of metallization paste has gradually become a research hotspot in the photovoltaic field and has become more and more urgent; at the same time, in order to reduce costs, many manufacturers want to use aluminum paste instead of silver paste, because the price of aluminum is much lower than that of silver, and the price of aluminum paste is only 100-200rmb / kg, and the resource volume and output of aluminum are larger, so there is no need to worry about supply problems, but using aluminum There are certain technical difficulties in using aluminum paste instead of silver paste and applying it on the back of the battery: the back of the TOPCon battery adopts a tunneling silicon oxide superimposed on a heavily doped passivated polysilicon structure to achieve back field passivation and carrier transport. When the aluminum paste contacts the polysilicon, the low-melting-point aluminum will diffuse with the polysilicon, resulting in the destruction of the polysilicon, and easily forming aluminum spikes (spikes of aluminum-silicon alloy inserted into the tunneling layer), causing a sharp deterioration of passivation and a sharp increase in the composite of the damaged metal contact area, resulting in a significant decrease in the open circuit voltage (Voc). This phenomenon will become more serious with the increase of the doping concentration of polysilicon. Therefore, the use of aluminum paste instead of silver paste has great technical difficulties and other deficiencies. The utility model cleverly solves the various deficiencies of the existing structure by overall design of the TOPCon battery structure. After adopting the TOPCon battery structure, a new isolation conductive film layer is added outside the back polysilicon layer, and then a groove is opened and an aluminum electrode is used to fill the groove and contact the electrode contact surface to form a new back structure. Therefore, on the one hand, the introduction of the isolation conductive film layer can well realize electron collection and conduction, and can also bring about further enhanced back field passivation effect. At the same time, aluminum paste printing is used to block the invasion of aluminum paste through the isolation conductive film layer, reduce the damage of aluminum paste to the silicon substrate, avoid a significant reduction in open circuit voltage (Voc), and achieve good contact with the electrode; on the other hand, aluminum paste can replace silver paste, reduce production costs, and greatly improve the efficiency of solar cells, meeting the market demand for high-efficiency and low-cost solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the TOPCon battery structure of Example 1;

[0024] Figure 2 Schematic diagram of the TOPCon battery structure of Example 2;

[0025] Figure 3 Schematic diagram of the TOPCon battery structure of Example 3;

[0026] Figure 4Schematic diagram of the TOPCon battery structure of Comparative Example 1;

[0027] Wherein: 1. silicon wafer body; 2. front structure layer; 20. boron-doped emitter; 21. AlO x layer; 22, front passivation layer; 3, back structural layer; 30, tunneling oxide layer; 31, polysilicon layer; 32, isolation conductive film layer; 33, back passivation layer; 330, groove; 4, front metal electrode; 5, back metal electrode. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the utility model is described in detail below in conjunction with the accompanying drawings and specific embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0029] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating 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, and do not indicate or imply 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.

[0030] In addition, the terms "first" and "second" are used for descriptive purposes only and should not 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 at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0031] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In the utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0033] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0034] Example 1

[0035] like Figure 1 As shown, the TOPCon cell structure provided in this embodiment includes a silicon wafer body 1, a front structure layer 2, a back structure layer 3, a front metal electrode 4 and a back metal electrode 5.

[0036] Specifically, the silicon wafer body 1 is an N-type single crystal silicon substrate; the resistivity of the silicon wafer body 1 is 0.5-3Ω·cm, and the thickness is 100-200μm. At the same time, the silicon substrate is cleaned, impurities and oxide layers on the surface are removed, and the back of the silicon wafer is polished and cleaned by texturing, boron diffusion on the front side, and alkaline solution, so that the front side is velvety and the back side is flat.

[0037] The front structure layer 2 includes a boron-doped emitter 20 formed on the front of the silicon wafer body 1, an AlO x A front passivation layer 21 and a front passivation layer 22 are formed, and a front metal electrode 4 is formed on an upper surface of the front passivation layer 22 .

[0038] The back structural layer 3 includes a tunneling oxide layer 30, a polysilicon layer 31, an isolation conductive film layer 32 and a back passivation layer 33 which are sequentially formed on the back of the silicon wafer body 1 from the inside to the outside.

[0039] In some specific embodiments, the tunnel oxide layer 30 is SiO x The polysilicon layer 31 is an n+poly-Si layer with a thickness of about 110 to 135 nm; the isolation conductive film layer 32 is a TiO2 film layer with a thickness of about 5 to 10 nm; the back passivation layer 33 is a SiNx The refractive index is 1.9-2.3, and the thickness is 70-100nm. In short, the introduction of a new isolation conductive film layer 32 outside the back polysilicon layer 31 can well realize electron collection and conduction, and can also further enhance the back field passivation effect. At the same time, this battery uses aluminum paste printing, and the isolation conductive film layer blocks the intrusion of aluminum paste, reduces the damage of aluminum paste to the silicon substrate, and achieves good contact with the electrode, so as to achieve the application of aluminum paste.

[0040] In this example, the isolation conductive film 32 layer fully covers the back side of the polysilicon layer 31, and the back passivation layer 33 forms equally spaced grooves 330 at the corresponding metal area. The portion of the isolation conductive film layer 32 corresponding to the groove 330 is exposed to form an electrode contact surface. The back metal electrode 5 is an aluminum electrode, and the aluminum electrode fills the groove 330 and contacts the electrode contact surface. Furthermore, the width of the metal area is greater than the width of the groove 330, and the aluminum electrode is formed on the back passivation layer 33 corresponding to the metal area from the portion exposed in the groove. Good contact between the isolation conductive film layer and the electrode is ensured, while reducing the metal contact resistance. The width of the metal paste electrode grid line of the aluminum electrode is 80 to 120 μm, and the width of the groove is 30 to 35 μm; the aluminum electrodes are symmetrically distributed about the center line of the groove. The aluminum electrodes correspond one to one to the grooves.

[0041] In some specific embodiments, a green light with a wavelength of 532nm, a power of 14-20W, and a frequency of about 2.0-3.0MHz is used as a laser source for intermittent irradiation, and holes are opened at equal intervals. The line width of the openings is 30-35μm to ensure good contact between the isolated conductive film layer and the electrode; then screen printing technology is used to print equidistant aluminum paste electrode grid lines in the laser opening area and high-temperature sintering is performed. At the same time, the width of the metal paste electrode grid line is 80-120μm. Since the resistivity of aluminum is slightly higher than that of silver and the opening needs to be filled, the width of the electrode should be slightly wider than the opening to reduce the metal contact resistance.

[0042] Example 2

[0043] like Figure 2 As shown, the TOPCon battery structure provided in this embodiment includes a silicon wafer body 1, a front structure layer 2, a back structure layer 3, a front metal electrode 4 and a back metal electrode 5. Its structure is basically the same as the TOPCon battery structure of Example 1, and the specific differences are as follows.

[0044] The isolation conductive film layer 32 in this embodiment is a magnesium oxide film layer (MgO film layer) with a thickness of about 5 to 10 nm. At the same time, the introduction of this layer (isolation conductive film layer 32) can well realize electron collection and conduction, and can also further enhance the back field passivation effect. At the same time, this battery is printed with aluminum paste, and the isolation conductive film layer blocks the intrusion of aluminum paste, reduces the damage of aluminum paste to the silicon substrate, and achieves good contact with the electrode, so as to achieve the application of aluminum paste.

[0045] Example 3

[0046] like Figure 3 As shown, the TOPCon cell structure provided in this embodiment includes a silicon wafer body 1, a front structure layer 2, a back structure layer 3, a front metal electrode 4 and a back metal electrode 5. Its structure is basically the same as the TOPCon cell structure of Example 1, and the differences are as follows. The isolation conductive film layer 32 in this embodiment is an AZO film layer (aluminum-doped zinc oxide film layer) with a thickness of about 30 to 100 nm; the back passivation layer 33 is SiN x layer, with a refractive index of 1.9 to 2.3 and a thickness of 70 to 100 nm. In short, the introduction of a new isolation conductive film layer 32 outside the back polysilicon layer 31 can well realize electron collection and conduction, and can also further enhance the back field passivation effect. At the same time, this battery is printed with aluminum paste, which blocks the intrusion of aluminum paste by isolating the conductive film layer, reduces the damage of aluminum paste to the silicon substrate, and achieves good contact with the electrode, thereby realizing the application of aluminum paste. In addition, AZO can be replaced by zinc oxide materials doped with elements including but not limited to manganese, titanium, and magnesium.

[0047] Comparative Example 1

[0048] like Figure 4 As shown, the TOPCon battery structure provided in this comparative example includes a silicon wafer body 1, a front structure layer 2, a back structure layer 3, a front metal electrode 4 and a back metal electrode 5. The structure of the silicon wafer body 1, the front structure layer 2 and the front metal electrode 4 are the same as those in Example 1, and the specific differences are as follows.

[0049] The back structure layer 3 of this comparative example 1 includes a tunneling oxide layer 30, an n+poly layer 31, and a back passivation layer 33 formed on the back of the silicon wafer body 1 from the inside to the outside, wherein the back metal electrode 5 is a silver electrode, and is printed with a burn-through silver paste in normal production, wherein the silver electrode burns through the bottom of the back passivation layer 33 and the n+poly layer 31.

[0050] Performance test: The batteries obtained in the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 4 were subjected to the following performance test, and the test method was: using an IV tester to test the battery photoelectric conversion efficiency and related electrical performance parameters under standard light power under a simulated solar light source (and the electrical performance data is the average value data of 100Pcs batteries of various samples). Specific test results are shown in Table 1 (Eta: conversion efficiency, Voc: open circuit voltage, Jsc: short circuit current density, FF: fill factor; Rs: contact resistance).

[0051] Table 1

[0052]

[0053] As can be seen from Table 1, compared with the conventional TOPCon battery structure, the conversion efficiency, open circuit voltage, short circuit current density, fill factor, contact resistance and other data of the TOPCon battery structure of this embodiment are very close. Therefore, it can be seen that the technical difficulties of using aluminum paste instead of silver paste have been overcome, and the production cost can be reduced, meeting the market demand for high-efficiency and low-cost solar cells.

[0054] Example 4

[0055] The photovoltaic module involved in this embodiment includes a front encapsulation layer, a photovoltaic cell, and a back encapsulation layer, wherein the photovoltaic cell is the TOPCon cell structure in the above-mentioned embodiment 1, 2 or 3.

[0056] Example 5

[0057] The photovoltaic system involved in this embodiment includes the photovoltaic components involved in Embodiment 4, wherein there are two or three or more photovoltaic components, and the multiple photovoltaic components are interconnected (generally connected in series).

[0058] Meanwhile, there may be only one photovoltaic module, that is, a photovoltaic system consisting of a single photovoltaic module; or there may be two or three or more photovoltaic modules, and the multiple photovoltaic modules may be relatively connected in series and / or in parallel.

[0059] In summary, after adopting the TOPCon battery structure, a new isolation conductive film layer is added outside the back polysilicon layer, and then a new back structure is formed by using grooves and aluminum electrodes to fill the grooves and contact the electrode contact surface. Therefore, on the one hand, the utility model can well realize electron collection and conduction by the introduction of the isolation conductive film layer, and can also bring about further enhancement of the back field passivation effect. At the same time, aluminum paste printing is used to block the invasion of aluminum paste through the isolation conductive film layer, reduce the damage of aluminum paste to the silicon substrate, avoid a significant reduction in the open circuit voltage (Voc), and achieve good contact with the electrode; on the other hand, aluminum paste can replace silver paste, reduce production costs, and greatly improve the efficiency of solar cells, meeting the market demand for high-efficiency and low-cost solar cells.

[0060] The above detailed description of the utility model is intended to enable people familiar with the technology in this field to understand the content of the utility model and implement it. It is not intended to limit the protection scope of the utility model. All equivalent changes or modifications made according to the spirit of the utility model should be included in the protection scope of the utility model.

Claims

1. A TOPCon cell structure, comprising a silicon wafer body (1), a front structural layer (2), a back structural layer (3), a front metal electrode (4) and a back metal electrode (5), characterized in that: The back structural layer (3) comprises a tunneling oxide layer (30), a polysilicon layer (31), an isolation conductive film layer (32) and a back passivation layer (33) which are sequentially formed on the back of the silicon wafer body (1) from the inside to the outside, wherein the isolation conductive film layer (32) fully covers the back of the polysilicon layer (31), the back passivation layer (33) forms a groove (330) at a corresponding metal region, and a portion of the isolation conductive film layer (32) corresponding to the groove (330) is exposed to form an electrode contact surface, and the back metal electrode (5) is an aluminum electrode, and the aluminum electrode fills the groove (330) and contacts the electrode contact surface.

2. The TOPCon battery structure according to claim 1, characterized in that: The isolation conductive film layer (32) is a magnesium oxide film layer, a titanium dioxide film layer or an aluminum-doped zinc oxide film layer; and / or when the isolation conductive film layer is an aluminum-doped zinc oxide film layer, the thickness is 30-100 nm; when the isolation conductive film layer is a magnesium oxide film layer or a titanium dioxide film layer, the thickness is 5-10 nm.

3. The TOPCon battery structure according to claim 1, characterized in that: The width of the metal region is greater than the width of the groove (330), and the aluminum electrode is formed on the back passivation layer (33) corresponding to the metal region from the portion exposed in the groove (330).

4. The TOPCon battery structure according to claim 3, characterized in that: The width of the metal paste electrode grid line of the aluminum electrode is 80 to 120 μm, and the width of the groove (330) is 30 to 35 μm; and / or the aluminum electrodes are symmetrically distributed about the center line of the groove (330).

5. The TOPCon battery structure according to claim 4, characterized in that: The grooves (330) are distributed at equal intervals on the back side of the back passivation layer (33); and the aluminum electrodes correspond to the grooves (330) one by one.

6. The TOPCon battery structure according to claim 1, characterized in that: The silicon wafer body (1) is an N-type single crystal silicon substrate; and / or the resistivity of the silicon wafer body (1) is 0.5 to 3Ω·cm and the thickness is 100 to 200 μm.

7. The TOPCon battery structure according to claim 1, characterized in that: The tunneling oxide layer (30) is SiO x layer, and the thickness is 0.8~1.2nm.

8. The TOPCon battery structure according to claim 1, characterized in that: The polysilicon layer (31) is an n+poly-Si layer, and has a thickness of 110-135 nm.

9. The TOPCon battery structure according to claim 1, characterized in that: The back passivation layer (33) is SiN x layer, with a refractive index of 1.9 to 2.3 and a thickness of 70 to 100 nm.

10. The TOPCon battery structure according to claim 1, characterized in that: The front surface of the silicon wafer body (1) is velvety, and the front structural layer (2) comprises a boron-doped emitter (20) formed on the front surface of the silicon wafer body (1), an AlO x A front passivation layer (21) and a front passivation layer (22), wherein the front metal electrode (4) is formed on the surface of the front passivation layer (22).

11. A photovoltaic module, comprising a front encapsulation layer, a photovoltaic cell, and a back encapsulation layer, characterized in that: The photovoltaic cell is a TOPCon cell structure as described in any one of claims 1 to 10.

12. A photovoltaic system, characterized in that: The photovoltaic system comprises the photovoltaic assembly as claimed in claim 11, wherein there are one or more photovoltaic assemblies, and when there are multiple photovoltaic assemblies, the multiple photovoltaic assemblies are interconnected.

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