Passivation contact structure, solar cell and manufacturing method thereof, photovoltaic module and photovoltaic system

Abstract

The invention discloses a passivation contact structure, a solar cell, a manufacturing method of the solar cell, a photovoltaic module and a photovoltaic system, and belongs to the technical field of solar cells. The passivation contact structure is arranged on a silicon substrate, a P-type doping layer is formed on the front surface of the silicon substrate, and the passivation contact structure comprises an N-type doping layer, a first passivation layer and a hole-shaped reverse electric leakage channel penetrating through the N-type doping layer, the first passivation layer, the silicon substrate and the P-type doping layer. A first doping layer is formed in the hole-shaped reverse electric leakage channel and connected with the P-type doping layer and the N-type doping layer, so that electrical contact between the front face and the back face can be achieved. By introducing a reverse electric leakage channel into the passivation contact structure, the reverse electric leakage capability of the solar cell can be improved, and along with the improvement of the electric leakage capability, when the solar cell is shielded at an assembly end, the reverse voltage at the two ends of the shielded solar cell can be reduced, and the heating power of the solar cell can be reduced; therefore, the purpose of controlling the hot spot risk is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and specifically relates to a passivation contact structure, a TOPCon passivation contact cell and a manufacturing method thereof, a photovoltaic module and a photovoltaic system. The passivation contact structure can be applied to a TOPCon cell (tunneling oxide passivation contact technology cell), an HJT cell (intrinsic thin film heterojunction cell), etc. Background Art

[0002] In the prior art, photovoltaic modules are usually composed of a battery array composed of multiple cells. In order to effectively control the risk of hot spots, a low reverse leakage current cell + bypass diode design is basically adopted to control the heating power of the leakage point by reducing the reverse leakage current of the cell. For the current mainstream passivated contact structure battery, mainly including TOPCon (tunnel oxide passivated contact), HJT and other high-efficiency batteries, the semiconductor doping layers on the front and back sides are completely isolated to control the leakage current at a very low level.

[0003] However, this design will bring two major problems: first, from the battery end, any defect introduced during the manufacturing process of solar cells may cause the leakage current to exceed the control value, so the production and manufacturing control requirements of the battery are high, resulting in a certain loss in battery yield; second, from the component end, the two doping layers with opposite conductivity types are completely isolated, which will make the battery have a higher reverse voltage, which in turn will cause the photovoltaic module to have a higher risk of hot spots during actual operation.

[0004] In order to solve the above-mentioned problems, after searching, Chinese patent CN118472072A discloses a back-contact battery and a method for making it, and a photovoltaic module. The back-contact battery obtained by the method for making the back-contact battery forms a reverse leakage channel in the edge area of ​​the battery, so that the heat generated by the back-contact battery after self-conduction is evenly distributed on the edge area of ​​the back-contact battery, solving the risk of local heat accumulation in the blocked area when the back-contact battery is blocked, forming a high-temperature point (i.e., hot spot). Chinese patent CN118658912A discloses a back-contact battery and a method for making it, and a photovoltaic module, wherein the back-contact battery includes: a semiconductor substrate, a first semiconductor layer, a second semiconductor layer, a transparent conductive layer, a leakage channel, and an isolation portion. The back-contact battery includes a leakage channel at least located between the first semiconductor layer and the second semiconductor layer, wherein the first semiconductor layer and the second semiconductor layer are both arranged on the first surface. By analyzing the above two structures, it can be found that although the problem of hot spots can be solved to a certain extent, there is still room for improvement. Summary of the invention

[0005] 1. Problem to be solved

[0006] In view of the technical problem that the above-mentioned passivated contact solar cells are prone to hot spot risks, resulting in low conversion efficiency of the solar cells, the purpose of the present invention is to propose a passivated contact structure to enhance the reverse conduction capability of the battery, reduce the reverse voltage of the battery, and improve the hot spot risk of the battery cell during actual operation.

[0007] Another object of the present invention is to provide a TOPCon passivated contact solar cell and a method for manufacturing the same.

[0008] Another object of the present invention is to provide a photovoltaic module having the above passivated contact solar cell.

[0009] Another object of the present invention is to provide a photovoltaic system having the photovoltaic module.

[0010] 2. Technical solution

[0011] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0012] The first aspect of the present invention provides a passivation contact structure, which is placed on a silicon substrate, a P-type doped layer is formed on the front surface of the silicon substrate, and the passivation contact structure includes an N-type doped layer, a first passivation layer, and a hole-shaped reverse leakage channel that penetrates the N-type doped layer, the first passivation layer, the silicon substrate, and the P-type doped layer. A first doped layer is formed inside the hole-shaped reverse leakage channel and is connected to the P-type doped layer and the N-type doped layer, so that electrical contact between the front and back surfaces can be achieved. The N-type doped layer is an N-type doped polysilicon layer or an N-type doped hydrogenated amorphous silicon layer; the P-type doped layer is a P-type doped polysilicon layer or a P-type doped hydrogenated amorphous silicon layer.

[0013] Among them, the silicon substrate of the solar cell has a front side facing the sun during normal operation and a back side opposite to the front side. The front side is the light-receiving side, and the back side is located on the other side of the silicon substrate relative to the front side; that is, the front side and the back side are located on different sides of the silicon substrate and are opposite sides.

[0014] It should be noted that the present invention can improve the reverse leakage capacity of solar cells by introducing a hole-shaped reverse leakage channel in the passivation contact structure and reasonably designing the reverse leakage channel structure. As the leakage capacity is improved, at the component end, when the solar cell is blocked, the reverse voltage at both ends of the blocked solar cell will be reduced, and the heating power of the solar cell will be reduced, thereby achieving the purpose of controlling the risk of hot spots.

[0015] According to any embodiment of the first aspect of the present invention, the number of the hole-shaped reverse leakage channels per unit area is 1-100, such as 1, 2, ..., 99, 100, and the number of the hole-shaped reverse leakage channels per unit area is also set according to actual use needs, and is not specifically limited here. The aperture size of the hole-shaped reverse leakage channel ranges from 10um to 200um, such as 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um and 200um.

[0016] According to any implementation of the first aspect of the present invention, the hole-shaped reverse leakage channels are uniformly or randomly distributed in the passivation contact structure, so that there is no need to strictly control the distribution state of the holes, which is conducive to improving production efficiency.

[0017] According to any embodiment of the first aspect of the present invention, the doping concentration of the N-type doping layer is 10 20 -10 21 atoms / cm 3 , with a thickness of 50-200 nm, for example, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm and 200 nm; the doping concentration of the P-type doping layer is 3*(10 18 -10 20 )atoms / cm 3 , the thickness is 0.5-2um, for example 0.5um, 0.6um, 0.7um, 0.8um, 0.9um, 1.0um, 1.1um, 1.2um, 1.3um, 1.4um, 1.5um, 1.6um, 1.7um, 1.8um, 1.9um, and 2.0um.

[0018] According to any embodiment of the first aspect of the present invention, the material of the first passivation layer is any one of SiO2, Al2O3 or SiC, and the thickness is 1-2nm, for example, 1nm, 1.1nm, 1.2nm, 1.3nm, 1.4nm, 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, 2.0nm. The thinner first passivation layer can improve the conductivity.

[0019] The first passivation layer can be set to be thicker than the existing tunneling layer, and it is set according to actual use needs, and is not specifically limited here. The first passivation layer not only passivates the surface of the silicon substrate, but also needs to allow carriers to tunnel through. When the thickness of the first passivation layer is too small, it cannot play a passivation role. When the thickness of the first passivation layer is too large, carriers cannot effectively tunnel.

[0020] A second aspect of the present invention provides a TOPCon passivated contact solar cell, comprising a silicon substrate and a passivation contact structure, wherein the passivation contact structure is placed on a silicon substrate, a P-type doped layer is formed on the front surface of the silicon substrate, the passivation contact structure comprises an N-type doped layer, a first passivation layer, and a hole-shaped reverse leakage channel penetrating the N-type doped layer, the first passivation layer, the silicon substrate and the P-type doped layer, wherein a first doped layer is formed inside the hole-shaped reverse leakage channel and connected to the P-type doped layer and the N-type doped layer, thereby enabling front and back electrical contact.

[0021] According to any embodiment of the second aspect of the present invention, the cross-sectional size of the hole-shaped reverse leakage channel is in the micrometer order, and the thickness of the first doped layer inside the hole-shaped reverse leakage channel is in the submicrometer order.

[0022] According to any embodiment of the second aspect of the present invention, the number of the hole-shaped reverse leakage channels per unit area is 1-100, for example, 1, 2, ..., 99, 100, and the number of the hole-shaped reverse leakage channels per unit area is also set according to actual use needs, and is not specifically limited here. The aperture size of the hole-shaped reverse leakage channel ranges from 10um to 200um, for example, 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um and 200um.

[0023] According to any embodiment of the second aspect of the present invention, the hole-shaped reverse leakage channels are uniformly or randomly distributed in the passivation contact structure, so that there is no need to strictly control the distribution state of the holes, which is conducive to improving production efficiency.

[0024] According to any embodiment of the second aspect of the present invention, the doping concentration of the N-type doping layer is 10 20 -10 21 atoms / cm 3, with a thickness of 50-200 nm, for example, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm and 200 nm; the doping concentration of the P-type doping layer is 3*(10 18 -10 20 )atoms / cm 3 , the thickness is 0.5-2um, for example 0.5um, 0.6um, 0.7um, 0.8um, 0.9um, 1.0um, 1.1um, 1.2um, 1.3um, 1.4um, 1.5um, 1.6um, 1.7um, 1.8um, 1.9um, and 2.0um.

[0025] According to any implementation scheme of the second aspect of the present invention, the N-type doped layer is an N-type doped polysilicon layer; and the P-type doped layer is a P-type doped polysilicon layer.

[0026] According to any embodiment of the second aspect of the present invention, the material of the first passivation layer is any one of SiO2, Al2O3 or SiC, and the thickness is 1-2nm, for example, 1nm, 1.1nm, 1.2nm, 1.3nm, 1.4nm, 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, 2.0nm. The thinner first passivation layer can improve the conductivity.

[0027] According to any embodiment of the second aspect of the present invention, the material of the second passivation layer is AlOx, and the thickness is 3-10nm, for example, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm.

[0028] A third aspect of the present invention provides a method for manufacturing a TOPCon passivated contact solar cell, comprising the steps of:

[0029] S01: Provide a silicon substrate, remove the surface damage layer of the N-silicon wafer substrate, and form a pyramid velvet structure on the surface. The pyramid base is 1-3um, for example, 1um, 1.1um, 1.2um, 1.3um, 1.4um, 1.5um, 1.6um, 1.7um, 1.8um, 1.9um, 2.0um, 2.1um, 2.2um, 2.3um, 2.4um, 2.5um, 2.6um, 2.7um, 2.8um, 2.9um, 3.0um, height is 0.5-2.5um, for example, 0.5um, 0.6um, 0.7um, 0.8um, 0.9um, 1.0um, 1.1um, 1.2um, 1.3um, 1.4um, 1.5um, 1.6um, 1.7um, 1.8um, 1.9um, 2.0um, 2.1um, 2.2um, 2.3um, 2.4um, 2.5um; in this way, the reflection of sunlight on the front side can be reduced and the photoelectric conversion efficiency can be improved;

[0030] S02: doping a first element on the front side of the silicon wafer at high temperature to form a first element-P type doping layer; the first element is mainly boron or gallium.

[0031] S03: A hole is opened from the back side of the silicon wafer; the aperture size of the porous reverse leakage channel ranges from 10um to 200um, for example, 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um and 200um.

[0032] Preferably, the hole is opened by high-energy laser, the laser wavelength is 532-1064nm, the pulse width is 0.1ns-10ps, and the laser energy density is 10 4 -10 7 W / mm 2 ; Existing technologies such as laser drilling, mechanical drilling, etc. can also be used.

[0033] S04: Back side polishing and removal of the damaged layer at the hole;

[0034] S05: grow a first passivation layer and a second element-N-type doping layer on the back and at the holes; at the same time, generate a second element-silicon glass layer with a thickness of 20-50nm on the surface of the N-type doping layer, for example, 20nm, 21nm, 22nm, 23nm, 24nm, 25nm, 26nm, 27nm, 28nm, 29nm, 30nm, 31nm, 32nm, 33nm, 34nm, 35nm, 36nm, 37nm, 38nm, 39nm, 40nm, 41nm, 42nm, 43nm, 44nm, 45nm, 46nm, 47nm, 48nm, 49nm, 50nm; the second element is mainly phosphorus.

[0035] S06: remove the N-type doped layer and the first element-silicon glass layer on the front side; remove the second element-silicon glass layer on the back side and the hole, and keep the N-type doped layer intact;

[0036] S07: ALD grows a second passivation layer on the front side and holes;

[0037] S08: growing a conductive layer on the front, back and holes;

[0038] S09: forming metal electrodes on the front and back sides to collect and transmit carriers, wherein the metal electrodes include silver electrodes, copper electrodes, aluminum electrodes, tin-coated copper electrodes or silver-coated copper electrodes.

[0039] According to any embodiment of the third aspect of the present invention, the doping concentration of the N-type doping layer is 10 20 -10 21 atoms / cm 3 , with a thickness of 50-200 nm, for example, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm and 200 nm; the doping concentration of the P-type doping layer is 3*(10 18 -10 20 )atoms / cm 3 The thickness is 0.5-2um, for example, 0.5um, 0.6um, 0.7um, 0.8um, 0.9um, 1.0um, 1.1um, 1.2um, 1.3um, 1.4um, 1.5um, 1.6um, 1.7um, 1.8um, 1.9um, and 2.0um. In this way, the lateral transport of carriers can be improved by light doping.

[0040] According to any embodiment of the third aspect of the present invention, the material of the first passivation layer is selected from any one of SiO2, Al2O3 or SiC, with a thickness of 1-2nm, for example, 1.0nm, 1.1nm, 1.2nm, 1.3nm, 1.4nm, 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, 2.0nm.

[0041] According to any embodiment of the third aspect of the present invention, the material of the second passivation layer is AlOx, and the thickness is 3-10nm, for example, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm.

[0042] According to any embodiment of the third aspect of the present invention, the material of the conductive layer is selected from one or more of SiNx, SiONx, and SiOx, and the thickness is 50-100nm, for example, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, and 100nm.

[0043] According to any implementation scheme of the third aspect of the present invention, the N-type doped layer is an N-type doped polysilicon layer; and the P-type doped layer is a P-type doped polysilicon layer.

[0044] A fourth aspect of the present invention provides a TOPCon passivated contact solar cell as described in the second aspect, or a photovoltaic module of a TOPCon passivated contact solar cell obtained by the method as described in the third aspect.

[0045] A fifth aspect of the present invention provides a photovoltaic system of the photovoltaic assembly described in the fourth aspect.

[0046] 3. Beneficial effects

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) The present invention can improve the reverse leakage capacity of solar cells by introducing a reverse leakage channel into the passivation contact structure and reasonably designing the reverse leakage channel structure. With the improvement of the leakage capacity, when the solar cell is blocked at the component end, the reverse voltage at both ends of the blocked solar cell will be reduced, and the heating power of the solar cell will be reduced, thereby achieving the purpose of controlling the risk of hot spots;

[0049] (2) The present invention introduces a reverse leakage channel structure, which has a protective effect on hot spots caused by defects in the silicon wafer itself, can reduce or even eliminate the requirements for defect control, and improve the yield of solar cells while reducing the risk of hot spots caused by defects;

[0050] (3) The passivation contact structure of the present invention introduces a hole-shaped reverse leakage channel, which is highly compatible with the current existing passivation contact structure battery manufacturing process, including TOPCon, HJT batteries, etc., and therefore has a high industrialization prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The technical solution of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for explanation purposes and are not intended to limit the scope of the present invention. In addition, unless otherwise specified, these drawings are intended only to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0052] Figure 1 The curve showing the variation of the heating power of the passivated contact battery according to the reverse conduction capability;

[0053] Figure 2 A top view of the passivation contact structure of the present invention;

[0054] Figure 3 It is a schematic diagram of the cross-sectional structure of the hole-shaped reverse leakage channel of the present invention;

[0055] Figure 4 This is a schematic diagram of the structure of a TOPCon passivated contact solar cell of the present invention;

[0056] Figure 5 It is a schematic diagram of the structure of the HJT passivation contact solar cell of the present invention.

[0057] Description of reference numerals:

[0058] 10. Silicon substrate; 11. P-type doping layer; 12. Second passivation layer; 13. First conductive layer;

[0059] 20. Passivation contact structure; 21. N-type doping layer; 22. First passivation layer; 23. Hole-shaped reverse leakage channel; 24. First doping layer;

[0060] 30. Positive silver electrode;

[0061] 40. Negative silver electrode. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0063] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0065] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They 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 position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0066] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0067] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] To explain the improvement of reverse conduction capability to reduce the risk of hot spots, Figure 1For explanation (the curve in the figure is only for the convenience of explanation, not the actual regular curve). First, as the reverse conduction capability of the battery gradually increases, the heat generation power also increases. The existing technology is to achieve low heat generation power by controlling the low reverse conduction capability, as shown in the red wireframe area in the figure; when the reverse current reaches the maximum value Impp, the heat generation power also reaches the maximum value, as shown in the purple wireframe area in the figure; when the reverse conduction capability continues to increase, since the reverse leakage current has reached the maximum value at this time, the reverse resistance becomes smaller, and the reverse voltage will gradually decrease, so the heat generation power will gradually decrease, as shown in the black wireframe area in the figure.

[0069] Combination Figure 2 and 3 As shown, the passivation contact structure 20 of the present invention is placed on a silicon substrate 10, and a P-type doping layer 11 is formed on the front surface of the silicon substrate 10. The passivation contact structure 20 includes an N-type doping layer 21, a first passivation layer 22, and a hole-shaped reverse leakage channel 23 that penetrates the N-type doping layer 21, the first passivation layer 22, the silicon substrate 10 and the P-type doping layer 11. A first doping layer 24 is formed inside the hole-shaped reverse leakage channel 23 and is connected to the P-type doping layer 11 and the N-type doping layer 21, so as to achieve front and back electrical contact.

[0070] It should also be noted that the present invention is essentially different from traditional MWT batteries. The hole area of ​​traditional MWT batteries is completely filled with electrode slurry. The function of the filling slurry is to collect the carriers (holes or electrons) generated on the front side to the PAD points on the back side, and the carriers generated on the front and back sides are in an electrically insulating state. There are differences in structure, principle, and purpose.

[0071] The present invention can significantly reduce the reverse voltage of the cell by introducing a reverse leakage channel into the passivated contact structure cell to improve the reverse conduction capability of the cell, thereby improving the hot spot risk of the photovoltaic module during actual operation.

[0072] Furthermore, the hole-shaped reverse leakage channel 23 at least satisfies the following conditions:

[0073] 1) The number of the hole-shaped reverse leakage channels per unit area is 1-100, for example, 1, 2, ..., 99, 100. The number of the hole-shaped reverse leakage channels per unit area is also set according to actual use needs, and is not specifically limited here. The number of the hole-shaped reverse leakage channels per unit area is also set according to actual use needs, and is not specifically limited here. The aperture size of the hole-shaped reverse leakage channel ranges from 10um to 200um, for example, 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um and 200um.

[0074] 2) The hole-shaped reverse leakage channels 23 are evenly or randomly distributed in the passivation contact structure. In this way, there is no need to strictly control the distribution state of the holes, which is conducive to improving production efficiency.

[0075] 3) The N-type doped layer is an N-type doped polysilicon layer or an N-type doped hydrogenated amorphous silicon layer; the P-type doped layer is a P-type doped polysilicon layer or a P-type doped hydrogenated amorphous silicon layer.

[0076] Furthermore, the doping concentration of the N-type doping layer is 10 20 -10 21 atoms / cm 3 , with a thickness of 50-200 nm, for example, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm and 200 nm; the doping concentration of the P-type doping layer is 3*(10 18 -10 20 )atoms / cm 3 The thickness is 0.5-2um, for example 0.5um, 0.6um, 0.7um, 0.8um, 0.9um, 1.0um, 1.1um, 1.2um, 1.3um, 1.4um, 1.5um, 1.6um, 1.7um, 1.8um, 1.9um, and 2.0um.

[0077] Furthermore, the material of the first passivation layer is selected from any one of SiO2, Al2O3 or SiC, and the thickness is 1-2nm, for example, 1.0nm, 1.1nm, 1.2nm, 1.3nm, 1.4nm, 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, 2.0nm. The above-mentioned thinner first passivation layer can improve the conductivity. The above-mentioned first passivation layer can be set to be as thick as the existing tunneling layer thickness, etc. It is set according to actual use needs and is not specifically limited here. The first passivation layer not only passivates the surface of the silicon substrate, but also needs to allow carriers to tunnel through. When the thickness of the first passivation layer is too small, it cannot play a passivation role. When the thickness of the first passivation layer is too large, the carriers cannot effectively tunnel.

[0078] The above-mentioned passivation contact structure is applied to a TOPCon passivation contact solar cell. The TOPCon passivation contact solar cell includes a silicon substrate 10 and a passivation contact structure 20. The passivation contact structure is placed on the silicon substrate 10. A P-type doping layer 11 is formed on the front surface of the silicon substrate 10. The passivation contact structure includes an N-type doping layer 21, a first passivation layer 22, and a hole-shaped reverse leakage channel 23 that penetrates the N-type doping layer, the first passivation layer, the silicon substrate, and the P-type doping layer. A first doping layer is formed inside the hole-shaped reverse leakage channel 23 and is connected to the P-type doping layer and the N-type doping layer, so that front and back electrical contacts can be achieved. Figure 4 or Figure 5 As shown, the hole-shaped reverse leakage channel 23 is not virtual but actually exists.

[0079] The method for manufacturing the TOPCon passivated contact solar cell comprises the following steps:

[0080] S01: Provide a silicon substrate, remove the surface damage layer of the N-type silicon wafer substrate, and form a pyramid velvet structure on the surface. The pyramid base is 1-3um, for example, 1um, 1.1um, 1.2um, 1.3um, 1.4um, 1.5um, 1.6um, 1.7um, 1.8um, 1.9um, 2.0um, 2.1um, 2.2um, 2.3um, 2.4um, 2.5um, 2.6um, 2.7um, 2.8um, 2.9um , 3.0um, height 0.5-2.5um, for example 0.5um, 0.6um, 0.7um, 0.8um, 0.9um, 1.0um, 1.1um, 1.2um, 1.3um, 1.4um, 1.5um, 1.6um, 1.7um, 1.8um, 1.9um, 2.0um, 2.1um, 2.2um, 2.3um, 2.4um, 2.5um; in this way, the reflection of sunlight on the front side can be reduced and the photoelectric conversion efficiency can be improved;

[0081] S02: doping a first element on the front side of the silicon wafer at high temperature to form a first element-P type doping layer; the first element is mainly boron or gallium.

[0082] S03: Opening a hole by incident light from the back side of the silicon wafer; the aperture size of the porous reverse leakage channel 23 ranges from 10um to 200um, for example, 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um and 200um.

[0083] Preferably, the hole is opened by high-energy laser, the laser wavelength is 532-1064nm, the pulse width is 0.1ns-10ps, and the laser energy density is 10 4 -10 7 W / mm 2 ; Existing technologies such as laser drilling, mechanical drilling, etc. can also be used.

[0084] S04: Back side polishing and removal of the damaged layer at the hole;

[0085] S05: growing a first passivation layer and a second element-N-type doping layer on the back and in the holes; generating a second element-silicon glass layer with a thickness of 20-50nm on the surface of the N-type doping layer; the second element is mainly phosphorus.

[0086] S06: removing the N-type doping layer and the first element-silicon glass layer on the front side (for example, removing phosphorus by using a 5% HF solution in the prior art); removing the second element-silicon glass layer on the back side and the hole, and leaving the N-type doping layer intact;

[0087] S07: ALD (atomic layer deposition) grows a second passivation layer 12 on the front surface and the holes;

[0088] S08: growing a conductive layer 13 on the front, back and holes;

[0089] S09: forming metal electrodes on the front and back sides to collect and transmit carriers, wherein the metal electrodes include silver electrodes, copper electrodes, aluminum electrodes, tin-coated copper electrodes or silver-coated copper electrodes.

[0090] Example 1

[0091] like Figure 4The TOPCon passivated contact solar cell shown, specifically, a 2nm thick silicon dioxide tunneling oxide layer is grown on the side wall of the silicon substrate base, and a 200nm thick N-type doped polysilicon layer is further grown on the silicon dioxide tunneling oxide layer, and the hole-shaped reverse leakage channel penetrates the silicon dioxide tunneling oxide layer.

[0092] like Figure 2 In area B, per unit area, there are a certain number of 100 porous reverse leakage channels distributed on the battery, with a pore size range of 100 um. The porous structure can be uniformly distributed or randomly distributed.

[0093] The internal structure of the hole is: a 2nm thick silicon dioxide tunneling oxide layer is grown on the side wall of the silicon wafer substrate, and a 200nm thick N-type doped polysilicon layer is continued to grow on the silicon dioxide oxide layer; since the hole size is at the micron level and the film thickness inside the hole is at the submicron level, the leakage channel is a hollow structure; the doped polysilicon layer inside the hole is connected to the p+ layer on the upper surface and the N-type doped polysilicon layer on the back, thereby achieving front and back electrical contact.

[0094] It should also be noted that the carriers generated on the front and back sides of the present invention are not in an electrically insulating state, and carrier transfer can be performed through the hole-shaped reverse leakage channel.

[0095] The method for manufacturing a TOPCon passivated contact solar cell of the present invention comprises the following steps:

[0096] S01: Provide a silicon substrate, remove the surface damage layer of the N-type silicon wafer substrate, and form a pyramid velvet structure on the surface. The pyramid base is 3um and the height is 2.5um. In this way, the reflection of sunlight from the front can be reduced and the photoelectric conversion efficiency can be improved;

[0097] S02: Boron is doped at high temperature on the front of the silicon wafer, with a doping depth of 2um and a surface doping concentration of 3*10 20 atoms / cm 3 ,Thus, by light doping, the lateral transport of carriers can be improved;

[0098] S03: A high-energy laser is used to open a hole from the back of the silicon wafer; the laser wavelength is 1064nm, the pulse width is 10ps, and the laser energy density is 10 7 W / mm 2 ;

[0099] S04: Back polishing, such as alkali polishing, acid polishing, mechanical polishing, etc., while removing the laser damaged layer at the hole

[0100] S05: Grow a 2nm silicon dioxide tunneling oxide layer and a 200nm thick N-type doped polysilicon layer on the back and in the hole. The phosphorus doping concentration of the polysilicon is 10 21 atoms / cm 3 , and at the same time, a 50nm thick phosphorus silicon glass layer is generated on the surface of the N-type doped polysilicon layer;

[0101] When an ultra-thin silicon dioxide tunneling oxide layer is prepared by a wet chemical process, the temperature is controlled at 20°C, the solution used is a pure nitric acid solution with a concentration of 69wt%, and the reaction time of the silicon wafer in the solution is controlled at 50 minutes; or when an ultra-thin silicon dioxide tunneling oxide layer is prepared by a high-temperature thermal oxidation process, the temperature is controlled at 800°C and the reaction is carried out for 60 minutes under pure oxygen conditions.

[0102] S06: remove the N-type doped polysilicon layer and borosilicate glass layer on the front side; remove the phosphosilicate glass layer on the back side and the hole, and keep the N-type doped polysilicon layer intact;

[0103] S07: ALD (atomic layer deposition) grows a 10nm thick Al2O3 layer on the front and holes;

[0104] S08: grow a layer of SiNx on the front, back and holes with a thickness of 100nm;

[0105] S09: Form a metal positive silver electrode 30 and a negative silver electrode 40 on the front and back sides to collect and transmit carriers.

[0106] The TOPCon passivated contact solar cell module of the present invention is compared with the TOPCon passivated contact solar cell module of the prior art, and the temperature test data are as follows:

[0107] The TOPCon passivation contact solar cell module of the present invention has different shielding areas, and each test temperature

[0108]

[0109] The test temperature of the existing TOPCon passivation contact solar cell module at different shading areas

[0110]

[0111]

[0112] Through comparison, it is found that when the solar cell of the present invention is blocked, the reverse voltage at both ends of the blocked solar cell will be reduced, and the heating power of the TOPCon passivated contact solar cell module of the prior art will increase. Compared with the TOPCon passivated contact solar cell module of the present invention, the heating power will be reduced, thereby achieving the purpose of controlling the risk of hot spots.

[0113]

[0114] From the data in the above table, it can be seen that the passivated contact solar cell of the present invention, wherein η=26.33%, Voc=738.5mV, has no performance degradation compared with the passivated contact solar cell of the prior art, and at the same time solves the hot spot problem of the passivated contact solar cell of the prior art.

[0115] Under AM1.5, 25℃ conditions, the open circuit voltage Voc, short circuit current Isc, fill factor FF, conversion efficiency Eff, and reverse leakage current IRev2 were measured. The comparative data are shown below.

[0116]

[0117] When bird droppings, leaves, sand and dust and other obstructions fall on the TOPCon passivated contact solar cell of the present invention, the temperature of the solar cell will not rise after being blocked by the obstruction to produce the hot spot effect. This solves the problem that the temperature generated by the hot spot exceeds a certain temperature value, which will cause the photovoltaic module to delaminate, the back panel to burn, the glass to burst, etc., and ensures the normal use of the entire solar cell module.

[0118] 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 modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A passivation contact structure, disposed on a silicon substrate, wherein a P-type doping layer is formed on the front surface of the silicon substrate, and the passivation contact structure comprises an N-type doping layer and a first passivation layer, characterized in that: It also includes a hole-shaped reverse leakage channel that penetrates the N-type doped layer, the first passivation layer, the silicon substrate and the P-type doped layer. A first doped layer is formed inside the hole-shaped reverse leakage channel and is connected to the P-type doped layer and the N-type doped layer, so that front and back electrical contacts can be achieved.

2. The passivation contact structure according to claim 1, characterized in that: The cross-sectional size of the hole-shaped reverse leakage channel is at the micron level, and the thickness of the first doping layer inside the hole-shaped reverse leakage channel is at the sub-micron level.

3. The passivation contact structure according to claim 2, characterized in that: The number of the hole-shaped reverse leakage channels per unit area is 1-100, and the aperture size ranges from 10um to 200um.

4. The passivation contact structure according to claim 3, characterized in that: The hole-shaped reverse leakage channels are evenly or randomly distributed in the passivation contact structure.

5. The passivation contact structure according to any one of claims 1 to 4, characterized in that: The doping concentration of the N-type doping layer is 10 20 -10 21 atoms / cm 3 , with a thickness of 50-200 nm; the doping concentration of the P-type doping layer is 3*(10 18 -10 20 )atoms / cm 3 , thickness is 0.5-2um.

6. The passivation contact structure according to claim 5, characterized in that: The N-type doped layer is an N-type doped polysilicon layer or an N-type doped hydrogenated amorphous silicon layer; the P-type doped layer is a P-type doped polysilicon layer or a P-type doped hydrogenated amorphous silicon layer.

7. A TOPCon passivated contact solar cell, comprising a silicon substrate, a P-type doped layer and a second passivation layer formed on the front surface of the silicon substrate, a passivation contact structure is arranged on the silicon substrate, and the passivation contact structure includes an N-type doped layer and a first passivation layer, characterized in that: It also includes a hole-shaped reverse leakage channel that penetrates the N-type doped layer, the first passivation layer, the silicon substrate and the P-type doped layer. A first doped layer is formed inside the hole-shaped reverse leakage channel and is connected to the P-type doped layer and the N-type doped layer, so that front and back electrical contacts can be achieved.

8. The TOPCon passivated contact solar cell according to claim 7, characterized in that: The cross-sectional size of the hole-shaped reverse leakage channel is at the micron level, and the thickness of the first doping layer inside the hole-shaped reverse leakage channel is at the sub-micron level.

9. The TOPCon passivated contact solar cell according to claim 8, characterized in that: The number of the hole-shaped reverse leakage channels per unit area is 1-100, and the aperture size ranges from 10um to 200um.

10. The TOPCon passivated contact solar cell according to claim 9, characterized in that: The hole-shaped reverse leakage channels are evenly or randomly distributed in the passivation contact structure.

11. The TOPCon passivated contact solar cell according to claim 10, characterized in that: The doping concentration of the N-type doping layer is 10 20 -10 21 atoms / cm 3 , with a thickness of 50-200 nm; the doping concentration of the P-type doping layer is 3*(10 18 -10 20 )atoms / cm 3 , thickness is 0.5-2um.

12. The passivation contact structure according to claim 11, characterized in that: The N-type doped layer is an N-type doped polysilicon layer; and the P-type doped layer is a P-type doped polysilicon layer.

13. The TOPCon passivated contact solar cell according to claim 7, characterized in that: The material of the first passivation layer is any one of SiO2, Al2O3 or SiC, and the thickness is 1-2nm.

14. The TOPCon passivated contact solar cell according to claim 7, characterized in that: The material of the second passivation layer is AlOx, and the thickness is 3-10nm.

15. A method for manufacturing a TOPCon passivated contact solar cell according to any one of claims 7 to 14, characterized in that: Includes steps: S01: Provide a silicon substrate, remove the surface damage layer of the N-silicon wafer substrate, and form a pyramid velvet structure on the surface. The pyramid base is 1-3um and the height is 0.5-2.5um; S02: doping the first element at high temperature on the front side of the silicon wafer to form a first element-P type doping layer; S03: Opening a hole from the back of the silicon wafer; S04: Back side polishing and removal of the damaged layer at the hole; S05: growing a first passivation layer and a second element-N-type doping layer on the back side and the hole; At the same time, a second element-silicon glass layer with a thickness of 20-50nm is generated on the surface of the N-type doped layer; S06: removing the N-type doping layer and the first element-silicon glass layer on the front side; removing the second element-silicon glass layer on the back side and the hole, and keeping the N-type doping layer intact.

16. The manufacturing method according to claim 15, characterized in that: Also includes the steps: S07: ALD grows a second passivation layer on the front side and holes; S08: growing a conductive layer on the front, back and holes; S09: Metal electrodes are formed on the front and back sides to collect and transmit carriers.

17. The manufacturing method according to claim 16, characterized in that: The doping concentration of the N-type doping layer is 10 20 -10 21 atoms / cm 3 , with a thickness of 50-200 nm; the doping concentration of the P-type doping layer is 3*(10 18 -10 20 )atoms / cm 3 , thickness is 0.5-2um.

18. The manufacturing method according to claim 16, characterized in that: The material of the second passivation layer is AlOx, and the thickness is 3-10nm.

19. The manufacturing method according to claim 16, characterized in that: The conductive layer is made of one or more of SiNx, SiONx, and SiOx, and has a thickness of 50-100 nm.

20. A photovoltaic module comprising a TOPCon passivated contact solar cell according to any one of claims 7 to 14, or a TOPCon passivated contact solar cell obtained by the method according to any one of claims 15 to 19.

21. A photovoltaic system comprising the photovoltaic module according to claim 20.

Images