Solar cell and passivation contact structure thereof, cell assembly and photovoltaic system

Abstract

The invention is applicable to the technical field of solar cells, and provides a solar cell and a passivation contact structure thereof, a cell module and a photovoltaic system, and the passivation contact structure of the solar cell comprises a passivation layer arranged on the surface of a silicon substrate; the quantum dot layer is arranged on one side, away from the silicon substrate, of the passivation layer and is provided with a plurality of quantum dots which are arranged at intervals; and the doping layer is arranged on one side, deviating from the silicon substrate, of the quantum dot layer. According to the solar cell passivation contact structure provided by the invention, the quantum dot layer is arranged between the doping layer and the passivation layer, so that the utilization rate of sunlight of different wave bands can be improved, the cell efficiency of the solar cell is improved, the thickness design of the doping layer can be reduced under the condition that the cell efficiency of the same solar cell is realized, and the solar cell efficiency is improved. And the production cost of the solar cell is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a solar cell and a passivation contact structure thereof, a cell assembly and a photovoltaic system. Background Art

[0002] Solar cells can convert sunlight into electrical energy by using the photovoltaic effect of semiconductors. Solar cells mainly include double-sided contact solar cells and back-contact solar cells. Among them, the back-contact solar cell has both positive and negative electrodes designed on the back of the cell. Compared with the double-sided contact solar cell, the front surface of the back-contact solar cell completely avoids the shading of the metal grid line, eliminating the optical loss caused by the shading of the metal grid line, which can greatly improve the cell conversion efficiency.

[0003] In the prior art, the solar cell passivation contact structure usually includes a passivation layer and a doping layer stacked in sequence on the surface of a silicon substrate, and the metal electrode of the solar cell contacts the doping layer to achieve the passivation contact of the solar cell. However, the solar cell passivation contact structure is usually set as a combination of a doped polysilicon layer with a smooth surface and a passivation layer, and the solar cell has low utilization rate of sunlight in different bands, resulting in low cell efficiency. Summary of the invention

[0004] The present invention provides a solar cell passivation contact structure, aiming to solve the problem that the solar cells in the prior art have low utilization rate of sunlight in different bands, resulting in low cell efficiency.

[0005] The present invention is implemented by providing a solar cell passivation contact structure, comprising:

[0006] A passivation layer disposed on the surface of the silicon substrate;

[0007] a quantum dot layer disposed on a side of the passivation layer away from the silicon substrate, the quantum dot layer having a plurality of quantum dots disposed at intervals; and

[0008] A doping layer is provided on a side of the quantum dot layer away from the silicon substrate.

[0009] Preferably, the quantum dot layer is one or a combination of a crystalline silicon quantum dot layer and a germanium quantum dot layer.

[0010] Preferably, the size of the quantum dots in a direction parallel to the passivation layer is less than 10 nanometers.

[0011] Preferably, the size of the quantum dots in a direction perpendicular to the passivation layer is 2 to 6 nanometers.

[0012] Preferably, it also includes:

[0013] The isolation layer is arranged between the quantum dot layer and the doping layer.

[0014] Preferably, the isolation layer is one or a combination of silicon carbide and silicon oxide.

[0015] Preferably, the thickness of the isolation layer is 1 to 5 nanometers.

[0016] Preferably, the doped layer is one of doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon, and doped amorphous silicon, or a combination of at least two of them.

[0017] The present invention also provides a solar cell, characterized in that it includes a silicon substrate, the silicon substrate includes a light-facing surface and a backlight surface arranged opposite to the light-facing surface, and the light-facing surface and / or the backlight surface are provided with the above-mentioned solar cell passivation contact structure.

[0018] Preferably, the solar cell is a back-contact solar cell, the backlight surface is provided with a P region and an N region, and the P region and the N region are both provided with the solar cell passivation contact structure; the doping layer in the P region is a P-type doping layer, and the doping layer in the N region is an N-type doping layer.

[0019] Preferably, the thickness of the isolation layer in the P region is greater than the thickness of the isolation layer in the N region.

[0020] Preferably, the thickness of the doping layer in the P region is greater than the thickness of the doping layer in the N region.

[0021] Preferably, the solar cell is a double-sided contact solar cell, one of the light-facing surface and the backlight surface is provided with a P region, and the other is provided with an N region, and both the P region and the N region are provided with the solar cell passivation contact structure; the doping layer in the P region is a P-type doping layer, and the doping layer in the N region is an N-type doping layer.

[0022] The present invention also provides a battery assembly, comprising the above-mentioned solar cell.

[0023] The present invention also provides a photovoltaic system, comprising the above-mentioned battery assembly.

[0024] The present invention provides a solar cell passivation contact structure. A quantum dot layer is arranged between a doping layer and a passivation layer. The quantum dot layer has a plurality of quantum dots arranged at intervals. The plurality of quantum dots in the quantum dot layer are used to enhance the light trapping effect of sunlight. Meanwhile, the quantum dot layer has a relatively high energy band width, which can enhance the utilization rate of sunlight in different wavebands, thereby enhancing the cell efficiency of the solar cell. Moreover, since the added quantum dot layer enhances the utilization rate of light in different wavebands, the thickness design of the doping layer can be reduced while achieving the same cell efficiency of the solar cell, thereby reducing the production cost of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic structural diagram of a solar cell passivation contact structure provided in Embodiment 1 of the present invention;

[0026] Figure 2 A schematic structural diagram of a quantum dot layer of a solar cell passivation contact structure provided in Embodiment 1 of the present invention;

[0027] Figure 3 A schematic diagram of the structure of a solar cell provided in Embodiment 2 of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of a solar cell provided in Embodiment 3 of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] An embodiment of the present invention provides a solar cell passivation contact structure, which comprises a quantum dot layer disposed between a doping layer and a passivation layer, wherein the quantum dot layer comprises a plurality of quantum dots disposed at intervals, and the plurality of quantum dots of the quantum dot layer are utilized to enhance the light trapping effect of sunlight, and at the same time, the utilization rate of sunlight in different wavebands can be enhanced, thereby enhancing the cell efficiency of the solar cell; moreover, since the added quantum dot layer enhances the utilization rate of light in different wavebands, the thickness design of the doping layer can be reduced while achieving the same cell efficiency of the solar cell, thereby reducing the production cost of the solar cell.

[0031] Embodiment 1

[0032] Please refer to Figure 1-Figure 2 The embodiment of the present invention provides a solar cell passivation contact structure 1, comprising:

[0033] A passivation layer 11 disposed on the surface of the silicon substrate 21;

[0034] a quantum dot layer 12 disposed on a side of the passivation layer 11 away from the silicon substrate 21, the quantum dot layer 12 having a plurality of quantum dots 121 disposed at intervals; and

[0035] The doping layer 13 is disposed on the side of the quantum dot layer 12 facing away from the silicon substrate 21 .

[0036] An embodiment of the present invention provides a solar cell passivation contact structure, wherein a quantum dot layer 12 is arranged between a doping layer 13 and a passivation layer 11, wherein the quantum dot layer 12 has a plurality of quantum dots 121 arranged at intervals, and the plurality of quantum dots 121 of the quantum dot layer 12 are used to enhance the light trapping effect of sunlight, and the quantum dot layer 12 has a large energy band width, which can enhance the utilization rate of sunlight in different bands, thereby enhancing the cell efficiency of the solar cell; moreover, since the added quantum dot layer 12 enhances the utilization rate of light in different bands, the thickness design of the doping layer 13 can be reduced while achieving the same cell efficiency of the solar cell, thereby reducing the production cost of the solar cell.

[0037] In the embodiment of the present invention, the silicon substrate 21 can be a P-type silicon substrate or an N-type silicon substrate. The surface of the silicon substrate 21 can be the light-facing surface or the backlight surface of the solar cell. The solar cell passivation contact structure can be arranged in the P region or the N region of the solar cell. The doped layer 13 is electrically connected to the silicon substrate 21 through the first passivation layer 11 and the quantum dot layer 12.

[0038] Among them, when the solar cell passivation contact structure 1 is set in the P region of the solar cell, the doping layer 13 is a P-type doping layer, and the electrode in the P region of the solar cell contacts the P-type doping layer; when the solar cell passivation contact structure is set in the N region of the solar cell, the doping layer 13 is an N-type doping layer, and the electrode in the N region of the solar cell contacts the N-type doping layer.

[0039] As an embodiment of the present invention, the passivation layer 11 is one of silicon oxide, silicon oxynitride, and silicon nitride, or a combination of at least two of them.

[0040] In this embodiment, the material of the passivation layer 11 can be one of silicon oxide, silicon oxynitride, silicon nitride, or a combination of at least two thereof. The passivation layer 11 plays a tunneling and passivation function on the surface of the silicon substrate 21, which is beneficial to improving the efficiency of the solar cell. The thickness of the passivation layer 11 can be set according to actual conditions. For example, the thickness of the passivation layer 11 can be 0.5 to 5 nanometers.

[0041] In the embodiment of the present invention, the quantum dot layer 12 includes an unlimited number of quantum dots 121, the quantum dots 121 are arranged in a uniform array or in an uneven array, and the quantum dot layer 12 can be arranged in a regular shape or an irregular shape. When the quantum dots 121 are arranged in a uniform array, it is beneficial for the quantum dot layer 12 to have good contact with the passivation layer 11.

[0042] As an embodiment of the present invention, the quantum dot layer 12 is one or a combination of a crystalline silicon quantum dot layer and a germanium quantum dot layer.

[0043] The quantum dot layer 12 may be a crystalline silicon quantum dot layer, a germanium quantum dot layer, or a stacked structure of a crystalline silicon quantum dot layer and a germanium quantum dot layer. When the quantum dot layer 12 is a crystalline silicon quantum dot layer, the quantum dot layer 12 has a plurality of arranged crystalline silicon quantum dots; when the quantum dot layer 12 is a germanium quantum dot layer, the quantum dot layer 12 has a plurality of arranged germanium quantum dots. In addition, the quantum dot layer 12 may also be a quantum dot layer of other Group IV elements.

[0044] As a preferred embodiment of the present invention, the quantum dot layer 12 is a crystalline silicon quantum dot layer. The crystalline silicon quantum dot layer has a wide energy band width. The crystalline silicon quantum dot layer is used in conjunction with the doping layer 13 to improve the utilization rate of solar cells for sunlight of different wavelengths, thereby improving the utilization rate of sunlight, and the cost of implementation is relatively low.

[0045] In specific applications, a passivation layer 11 is first deposited on the silicon substrate 21, and then a 2-6 nanometer amorphous silicon layer is deposited on the passivation layer 11, and then the amorphous silicon layer is subjected to high temperature annealing to become a crystalline silicon quantum dot layer. The preparation process is simple and the implementation cost is low. Among them, the crystallization rate of the crystalline silicon quantum dot layer is greater than 60%, which can make the crystalline silicon quantum dot layer 12 have a good energy band width, which is conducive to improving the battery efficiency of the solar cell.

[0046] As an embodiment of the present invention, the size of the quantum dot 121 in the direction parallel to the passivation layer 11 is less than 10 nanometers. Figure 2 As shown, the direction parallel to the passivation layer 11 specifically includes a first direction X and a second direction Y perpendicular to the first direction X.

[0047] In this embodiment, the size of the quantum dot 121 in the direction parallel to the passivation layer 11 is less than 10 nanometers, that is, the maximum size of the quantum dot 121 in the first direction X and the second direction Y parallel to the passivation layer 11 are both less than 10 nanometers, so that the quantum dot 121 can achieve a relatively suitable roughness, which is conducive to achieving a good sunlight trapping effect; moreover, the crystalline silicon quantum dot layer 12 can have a suitable energy band width, which is conducive to improving the cell efficiency of solar cells.

[0048] The size of the quantum dot 121 in the direction parallel to the passivation layer 11 can be understood as the maximum size of the quantum dot 121 in the direction parallel to the passivation layer 11. The sizes of different quantum dots 121 in the first direction X and the second direction Y parallel to the passivation layer 11 can be the same or different. The size of the quantum dot 121 in the first direction X and the second direction Y parallel to the passivation layer 11 can be set according to actual conditions.

[0049] For example, the size of the quantum dots 121 in the direction parallel to the passivation layer 11 can be 1.0 nanometers, or 1.2 nanometers, or 1.5 nanometers, or 1.9 nanometers, or 2.0 nanometers, or 2.2 nanometers, or 2.5 nanometers, or 2.9 nanometers, or 3.0 nanometers, or 3.5 nanometers, or 3.7 nanometers, or 3.9 nanometers, or 4.0 nanometers, or 4.1 nanometers, or 4.4 nanometers, or 5.0 nanometers, or 5.6 nanometers, or 6.0 nanometers, or 6.1 nanometers, or 6.8 nanometers, or 7.3 nanometers, or 7.9 nanometers, or 8.0 nanometers, or 8.6 nanometers, or 9.5 nanometers, or 10.0 nanometers.

[0050] like Figure 1 As shown, as an embodiment of the present invention, the size of the quantum dot 12 in the direction Z perpendicular to the passivation layer 11 is 2 to 6 nanometers.

[0051] In this embodiment, it can be understood that the thickness of the quantum dot layer 12 is 2 to 6 nanometers, and the size of the quantum dot 121 in the direction Z perpendicular to the passivation layer 11 is 2 to 6 nanometers, which is conducive to the quantum dot 121 and the passivation layer 11 to form a good contact, ensuring a good conductive effect between the quantum dot 121 and the passivation layer 11.

[0052] For example, the size of the quantum dots 121 in the direction Z perpendicular to the passivation layer 11 can be 2.0 nanometers, or 2.1 nanometers, or 2.4 nanometers, or 2.9 nanometers, or 3.0 nanometers, or 3.5 nanometers, or 3.7 nanometers, or 3.9 nanometers, or 4.0 nanometers, or 4.1 nanometers, or 4.4 nanometers, or 5.0 nanometers, or 5.6 nanometers, or 6.0 nanometers.

[0053] As an embodiment of the present invention, the solar cell passivation contact structure 1 further includes:

[0054] The isolation layer 14 is disposed between the quantum dot layer 12 and the doping layer 13 .

[0055] In the present embodiment, an isolation layer 14 is provided between the quantum dot layer 12 and the doping layer 13 to isolate the quantum dot layer 12 from the doping layer 13, which is beneficial to the formation of the quantum dot layer 12 and can maintain the structural stability of the quantum dot layer 12; moreover, the quantum dot layer 12 can ensure good carrier transmission performance, and at the same time, the quantum dot layer 12 has a good passivation effect, which is beneficial to improving battery efficiency.

[0056] As an embodiment of the present invention, the isolation layer 14 is one or a combination of silicon carbide and silicon oxide.

[0057] In this embodiment, the material of the isolation layer 14 may be a layer of silicon carbide, a layer of silicon oxide, or a stacked structure of silicon carbide and silicon oxide.

[0058] As an embodiment of the present invention, the thickness of the isolation layer 14 is 1 to 5 nanometers.

[0059] In this embodiment, the thickness of the isolation layer 14 is set within the range of 1 to 5 nanometers, which not only has a good isolation effect between the quantum dot layer 12 and the doping layer 13, but also ensures good carrier transmission performance and has a good passivation effect.

[0060] In this embodiment, the thickness of the isolation layer 14 can be set according to actual needs. For example, the thickness of the isolation layer 14 is 1.0 nanometers, or 1.2 nanometers, or 1.4 nanometers, or 1.5 nanometers, or 1.7 nanometers, or 1.9 nanometers, or 2.0 nanometers, or 2.2 nanometers, or 2.3 nanometers, or 2.5 nanometers, or 2.7 nanometers, or 2.9 nanometers, or 3.0 nanometers, or 3.2 nanometers, or 3.5 nanometers, or 3.7 nanometers, or 3.9 nanometers, or 4.0 nanometers, or 4.1 nanometers, or 4.4 nanometers, or 4.6 nanometers, or 4.9 nanometers, or 5.0 nanometers.

[0061] As an embodiment of the present invention, the doping layer 13 is one of doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon, and doped amorphous silicon, or a combination of at least two of them.

[0062] The material of the doping layer 13 can be set according to actual needs. The doping layer 13 can be doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon or doped amorphous silicon, or the doping layer 13 can be a combination of at least two of doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon or doped amorphous silicon. Preferably, the doping layer 13 is doped polycrystalline silicon.

[0063] In this embodiment, the doping layer 13 is a P-type doping layer doped with a P-type dopant or an N-type doping layer doped with an N-type dopant. The P-type dopant is a IIIA group element dopant, and the N-type dopant is a VA group element dopant. For example, the P-type dopant may be a boron dopant, and the N-type dopant may be a phosphorus dopant.

[0064] In the embodiment of the present invention, the doping layer 13 may be a single doping layer, or may include two doping layers 13. Of course, the solar cell passivation contact structure may also include three or more doping layers to further enhance the cell passivation effect.

[0065] As an embodiment of the present invention, the solar cell passivation contact structure 1 further includes:

[0066] The back passivation film layer 15 is disposed on the side of the doped layer 13 away from the silicon substrate 21 .

[0067] In this embodiment, the electrode of the solar cell contacts the doping layer 13 through the back passivation film layer 15. Among them, the back passivation film layer 15 is used to passivate and protect the back of the doping layer 13, which is beneficial to further improve the efficiency of the battery. Among them, the back passivation film layer 15 can be one or a combination of at least two of silicon nitride, silicon oxynitride, and silicon oxide. For example, the back passivation film layer 15 can be sequentially stacked on aluminum oxide and silicon nitride on the doping layer 13, which can achieve a good passivation effect on the back of the doping layer 13 and have a good protection function for the doping layer 13.

[0068] An embodiment of the present invention provides a solar cell passivation contact structure, and a solar cell uses the solar cell passivation contact structure. Since the solar cell passivation contact structure is provided with a quantum dot layer 12 between a doping layer 13 and a passivation layer 11, and the quantum dot layer 12 has a plurality of quantum dots 121 arranged at intervals, the plurality of quantum dots 121 of the quantum dot layer 12 are used to improve the light trapping effect of sunlight, and at the same time, the energy band width can be increased, and the utilization rate of sunlight in different bands can be improved, thereby improving the cell efficiency of the solar cell; moreover, under the condition of achieving the same cell efficiency of the solar cell, since the added quantum dot layer 12 improves the utilization rate of light in different bands, the thickness design of the doping layer 13 can be thinned, and the production cost of the solar cell can be reduced.

[0069] Embodiment 2

[0070] Please refer to Figure 3 This embodiment provides a solar cell 2, including a silicon substrate 21, the silicon substrate 21 includes a light-facing surface 211 and a backlight surface 212 arranged opposite to the light-facing surface 211, and the backlight surface 212 is provided with the solar cell passivation contact structure 1 of the above-mentioned embodiment 1.

[0071] In the embodiment of the present invention, the solar cell is a back-contact solar cell, and the backlight surface 212 of the back-contact solar cell is provided with a P region 213 and an N region 214, and both the P region 213 and the N region 214 are provided with a solar cell passivation contact structure 1; the doping layer 13 of the P region 213 is a P-type doping layer, and the doping layer 13 of the N region 214 is an N-type doping layer.

[0072] As an embodiment of the present invention, the solar cell 2 further includes:

[0073] A first electrode 25 disposed in the P region 213 , the first electrode 25 is in contact with the doping layer 13 in the P region 213 ;

[0074] The second electrode 26 is provided in the N region 214, and the second electrode 26 contacts the doping layer 13 of the N region 214. In this embodiment, the first electrode 25 contacts the doping layer 13 of the P region 213 to form an ohmic contact, and the second electrode 26 contacts the doping layer 13 of the N region 214 to achieve current extraction of the solar cell. Specifically, the first electrode 25 contacts the doping layer 13 through the back passivation film layer 15 at the position of the P region 213, and the second electrode 26 contacts the doping layer 13 through the back passivation film layer 15 at the position of the N region 214.

[0075] In this embodiment, there are multiple P regions 213 and multiple N regions 214, and multiple P regions 213 and multiple N regions 214 are alternately arranged in sequence. Among them, an isolation region 215 is arranged between adjacent P regions 213 and N regions 214. The isolation region 215 can be a groove or a gap, so that the P region 213 and the N region 214 are well isolated.

[0076] in, Figure 3 The P region 213 and the N region 214 of the back contact solar cell shown in the figure are both provided with the solar cell passivation contact structure of the above-mentioned embodiment 1. Of course, in some other embodiments, only one of the P region 213 and the N region 214 may be provided with the solar cell passivation contact structure of the above-mentioned embodiment 1. For example, only the P region 213 is provided with the solar cell passivation contact structure of the above-mentioned embodiment 1, and the N region 214 is provided with other existing conventional solar cell passivation contact structures; or, only the N region 214 is provided with the solar cell passivation contact structure of the above-mentioned embodiment 1, and the P region 213 is provided with other existing conventional solar cell passivation contact structures.

[0077] The present embodiment provides a solar cell using the solar cell passivation contact structure. Since the solar cell passivation contact structure has a quantum dot layer 12 disposed between the doping layer 13 and the passivation layer 11, the quantum dot layer 12 has a plurality of quantum dots 121 disposed at intervals. The plurality of quantum dots 121 of the quantum dot layer 12 are used to enhance the light trapping effect of sunlight, and at the same time, the energy band width can be increased, and the utilization rate of sunlight in different bands can be enhanced, thereby enhancing the cell efficiency of the solar cell. Moreover, under the condition of achieving the same cell efficiency of the solar cell, since the added quantum dot layer 12 enhances the utilization rate of light in different bands, the thickness design of the doping layer 13 can be reduced, thereby reducing the production cost of the solar cell.

[0078] As an embodiment of the present invention, the thickness of the doping layer 13 in the P region 213 is greater than the thickness of the doping layer 13 in the N region 214 .

[0079] It can be understood that increasing the thickness of the doping layer 13 in the P region 213 is beneficial to improving the passivation effect of the doping layer 13 in the P region 213 and the ability of the doping layer 13 in the P region 213 to block the burn-through of the electrode slurry, thereby reducing metallization damage and improving battery efficiency.

[0080] As an embodiment of the present invention, the thickness of the isolation layer 14 in the P region 213 is greater than the thickness of the isolation layer 14 in the N region 214 .

[0081] In this embodiment, the thickness of the isolation layer 14 of the P region 213 is greater than that of the isolation layer 14 of the N region 214. It can be understood that by thinning the thickness of the isolation layer 14 of the N region 214, the tunneling effect of the isolation layer 14 of the N region 214 is improved, thereby improving the battery efficiency.

[0082] Embodiment 3

[0083] Please refer to Figure 4 This embodiment provides a solar cell, including a silicon substrate 21, the silicon substrate 21 includes a light-facing surface 211 and a backlight surface 212 arranged opposite to the light-facing surface 211, and the light-facing surface 211 and / or the backlight surface 212 are both provided with the solar cell passivation contact structure of the above-mentioned embodiment 1.

[0084] As an embodiment of the present invention, the solar cell 2 is a double-sided contact solar cell, and one of the light-facing surface 211 and the backlight surface 212 of the double-sided contact solar cell is provided with a P region 213, and the other is provided with an N region 214, and both the P region 213 and the N region 214 are provided with a solar cell passivation contact structure; the doping layer 13 of the P region 213 is a P-type doping layer, and the doping layer 13 of the N region 214 is an N-type doping layer.

[0085] As an embodiment of the present invention, the solar cell 2 further includes:

[0086] A first electrode 25 disposed in the P region 213 , the first electrode 25 is in contact with the doping layer 13 in the P region 213 ;

[0087] The second electrode 26 is provided in the N region 214 , and the second electrode 26 is in contact with the doping layer 13 of the N region 214 .

[0088] In this embodiment, the first electrode 25 contacts the doping layer 13 of the P region 213 to form an ohmic contact, and the second electrode 26 contacts the doping layer 13 of the N region 214 to achieve current extraction of the solar cell. Specifically, the first electrode 25 contacts the doping layer 13 through the back passivation film layer 15 at the position of the P region 213, and the second electrode 26 contacts the doping layer 13 through the back passivation film layer 15 at the position of the N region 214.

[0089] In this embodiment, the number of P regions 213 and N regions 214 are both multiple, and multiple P regions 213 are alternately arranged on the light-facing surface 211, and multiple N regions 214 are alternately arranged on the backlight surface 212; or multiple N regions 214 are alternately arranged on the light-facing surface 211, and multiple P regions 213 are alternately arranged on the backlight surface 212. Figure 4 The figure only shows that a plurality of P regions 213 are alternately arranged on the light-facing surface 211, and a plurality of N regions 214 are alternately arranged on the backlight surface 212. Of course, the P regions 213 can also be arranged on the backlight surface 212, and the N regions 214 can be arranged on the light-facing surface 211.

[0090] in, Figure 4 The P region 213 and the N region 214 of the back contact solar cell shown in the figure are both provided with the solar cell passivation contact structure of the above-mentioned embodiment 1. Of course, in some other embodiments, only one of the P region 213 and the N region 214 may be provided with the solar cell passivation contact structure of the above-mentioned embodiment 1. For example, only the P region 213 is provided with the solar cell passivation contact structure of the above-mentioned embodiment 1, and the N region 214 is provided with other existing conventional solar cell passivation contact structures; or, only the N region 214 is provided with the solar cell passivation contact structure of the above-mentioned embodiment 1, and the P region 213 is provided with other existing conventional solar cell passivation contact structures.

[0091] Among them, the P region 213 may completely cover the light-facing surface 211 of the silicon substrate 21, or may only cover a part of the light-facing surface 211 of the silicon substrate 21; the N region 214 may completely cover the backlight surface of the silicon substrate 21, or may only cover a part of the backlight surface 212 of the silicon substrate 21. Preferably, the P region 213 covers a part of the light-facing surface 211 of the silicon substrate 21, and two adjacent P regions 213 are arranged at intervals, so that the doping layer of the light-facing surface 211 only covers a part of the light-facing surface 211 of the silicon substrate 21; the N region 214 only covers a part of the backlight surface 212 of the silicon substrate 211, and two adjacent N regions 214 are arranged at intervals, so that the doping layer of the backlight surface 212 only covers a part of the light-facing surface 211 of the silicon substrate 21, which can reduce light parasitic absorption.

[0092] The present embodiment provides a solar cell using the solar cell passivation contact structure. Since the solar cell passivation contact structure has a quantum dot layer 12 disposed between the doping layer 13 and the passivation layer 11, the quantum dot layer 12 has a plurality of quantum dots 121 disposed at intervals. The plurality of quantum dots 121 of the quantum dot layer 12 are used to enhance the light trapping effect of sunlight, and at the same time, the energy band width can be increased, and the utilization rate of sunlight in different bands can be enhanced, thereby enhancing the cell efficiency of the solar cell. Moreover, under the condition of achieving the same cell efficiency of the solar cell, since the added quantum dot layer 12 enhances the utilization rate of light in different bands, the thickness design of the doping layer 13 can be reduced, thereby reducing the production cost of the solar cell.

[0093] As an embodiment of the present invention, the thickness of the doping layer 13 in the P region 213 is greater than the thickness of the doping layer 13 in the N region 214 .

[0094] It can be understood that increasing the thickness of the doping layer 13 in the P region 213 is beneficial to improving the passivation effect of the doping layer 13 in the P region 213 and the ability of the doping layer 13 in the P region 213 to block the burn-through of the electrode slurry, thereby reducing metallization damage and improving battery efficiency.

[0095] As an embodiment of the present invention, the thickness of the isolation layer 14 in the P region 213 is greater than the thickness of the isolation layer 14 in the N region 214 .

[0096] In this embodiment, the thickness of the isolation layer 14 of the P region 213 is greater than that of the isolation layer 14 of the N region 214. It can be understood that by thinning the thickness of the isolation layer 14 of the N region 214, the tunneling effect of the isolation layer 14 of the N region 214 is improved, thereby improving the battery efficiency.

[0097] Embodiment 4

[0098] The embodiment of the present invention further provides a battery assembly, which includes the solar cell of the above embodiment 2 or embodiment 3. It should be noted that the battery assembly has the same or similar beneficial effects as the above solar cell 2, and the relevant parts between the two can be referenced to each other. In order to avoid repetition, it will not be repeated here.

[0099] In this embodiment, multiple solar cells 2 in the battery assembly can be connected in series in sequence to form a battery string, thereby realizing the series bus output of current. For example, the series connection of battery cells can be realized by setting welding strips (bus bars, interconnecting strips), conductive backplanes, etc.

[0100] It is understandable that in such an embodiment, the battery assembly may further include a metal frame, a back plate, photovoltaic glass and an adhesive film. The adhesive film may be filled between the front and back of the solar cell 2 and the photovoltaic glass, adjacent cells, etc. As a filler, it may be a transparent colloid with good light transmission and aging resistance. For example, the adhesive film may be an EVA adhesive film or a POE adhesive film. The specific selection may be based on actual conditions and is not limited here.

[0101] Photovoltaic glass can cover the adhesive film on the front of the solar cell 2. The photovoltaic glass can be ultra-white glass, which has high light transmittance, high transparency, and excellent physical, mechanical and optical properties. For example, the light transmittance of ultra-white glass can reach more than 92%, which can protect the solar cell without affecting the efficiency of the solar cell as much as possible. At the same time, the adhesive film can bond the photovoltaic glass and the solar cell 2 together. The presence of the adhesive film can seal and insulate the solar cell 2 and make it waterproof and moisture-proof.

[0102] The back panel can be attached to the adhesive film on the back of the solar cell 2. The back panel can protect and support the solar cell 2 and has reliable insulation, water resistance and aging resistance. There are multiple options for the back panel, which can usually be tempered glass, organic glass, aluminum alloy TPT composite adhesive film, etc. It can be set according to specific circumstances and is not limited here. The whole composed of the back panel, solar cell 2, adhesive film and photovoltaic glass can be set on a metal frame. The metal frame serves as the main external support structure of the entire solar cell assembly and can stably support and install the solar cell assembly. For example, the solar cell assembly can be installed at the required location through the metal frame.

[0103] Embodiment 5

[0104] The embodiment of the present invention further provides a photovoltaic system, which includes the battery assembly of the above-mentioned embodiment 4. It should be noted that the photovoltaic system has the same or similar beneficial effects as the above-mentioned solar cell 2, and the relevant parts between the two can be referenced to each other. In order to avoid repetition, they will not be described here.

[0105] In this embodiment, the photovoltaic system can be applied to photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be applied to equipment or devices that use solar energy to generate electricity, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking the photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a junction box and an inverter. The photovoltaic array may be an array combination of multiple solar cell modules. For example, multiple solar cell modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the junction box. The junction box can converge the current generated by the photovoltaic array. The converged current flows through the inverter and is converted into the alternating current required by the mains power grid, and then connected to the mains network to realize solar power supply.

[0106] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A solar cell passivation contact structure, characterized in that: include: A passivation layer disposed on the surface of the silicon substrate; A quantum dot layer disposed on a side of the passivation layer away from the silicon substrate, the quantum dot layer having a plurality of quantum dots disposed at intervals; and A doping layer is provided on a side of the quantum dot layer away from the silicon substrate.

2. The solar cell passivation contact structure according to claim 1, characterized in that: The quantum dot layer is one or a combination of a crystalline silicon quantum dot layer and a germanium quantum dot layer.

3. The solar cell passivation contact structure according to claim 1, characterized in that: The size of the quantum dots in a direction parallel to the passivation layer is less than 10 nanometers.

4. The solar cell passivation contact structure according to claim 3, characterized in that: The size of the quantum dots in a direction perpendicular to the passivation layer is 2 to 6 nanometers.

5. The solar cell passivation contact structure according to claim 1, characterized in that: Also includes: The isolation layer is arranged between the quantum dot layer and the doping layer.

6. The solar cell passivation contact structure according to claim 5, characterized in that: The isolation layer is one or a combination of silicon carbide and silicon oxide.

7. The solar cell passivation contact structure according to claim 5, characterized in that: The thickness of the isolation layer is 1 to 5 nanometers.

8. The solar cell passivation contact structure according to claim 1, characterized in that: The doped layer is one of doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon, and doped amorphous silicon, or a combination of at least two of them.

9. A solar cell, characterized in that: The invention comprises a silicon substrate, wherein the silicon substrate comprises a light-facing surface and a backlight surface arranged opposite to the light-facing surface, and the light-facing surface and / or the backlight surface are provided with a solar cell passivation contact structure as claimed in any one of claims 1 to 8.

10. The solar cell according to claim 9, characterized in that: The solar cell is a back-contact solar cell, the backlight surface is provided with a P region and an N region, and the P region and the N region are both provided with the solar cell passivation contact structure; the doping layer in the P region is a P-type doping layer, and the doping layer in the N region is an N-type doping layer.

11. The solar cell according to claim 10, characterized in that The thickness of the isolation layer in the P region is greater than the thickness of the isolation layer in the N region.

12. The solar cell according to claim 10, characterized in that: The thickness of the doping layer in the P region is greater than the thickness of the doping layer in the N region.

13. The solar cell according to claim 10, characterized in that: The solar cell is a double-sided contact solar cell, one of the light-facing surface and the backlight surface is provided with a P region, and the other is provided with an N region, and both the P region and the N region are provided with the solar cell passivation contact structure; the doping layer in the P region is a P-type doping layer, and the doping layer in the N region is an N-type doping layer.

14. A battery assembly, characterized in that: The invention comprises a solar cell as claimed in any one of claims 1 to 13.

15. A photovoltaic system, characterized in that: Comprising the battery assembly as claimed in claim 14.

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