A solar cell, its passivated contact structure, a battery module and a photovoltaic system

Abstract

The present invention is applicable to the technical field of solar cells, and provides a solar cell, a passivated contact structure thereof, a battery module and a photovoltaic system. The passivated contact structure of the solar cell includes a first passivation layer, a first doped polysilicon layer, a first barrier layer, and a second doped polysilicon layer that are sequentially stacked on the surface of a silicon substrate. The doping polarity of the first doped polysilicon layer is the same as that of the second doped polysilicon layer. Among them, the thickness of the first passivation layer is greater than the thickness of the first barrier layer. The passivated contact structure of the solar cell provided by the present invention adds a first barrier layer and a second doped polysilicon layer, and uses the first passivation layer and the first barrier layer to jointly block the diffusion of impurities into the interior of the silicon substrate, reducing the inward diffusion of impurities into the silicon substrate, which can significantly improve the passivation effect of the solar cell, thereby improving the battery efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and particularly relates to a solar cell, a passivated contact structure thereof, a battery module and a photovoltaic system. Background Art

[0002] Solar cells can convert sunlight into electrical energy by utilizing the photovoltaic effect of semiconductors. Solar cells mainly include bifacial solar cells and back-contact solar cells. Among them, since the positive / negative electrodes of the back-contact solar cells are both designed on the back of the cells, compared with bifacial solar cells, the front surface of the back-contact solar cells completely avoids the shading of metal grid lines, eliminating the optical losses caused by the shading of metal grid lines, and can greatly improve the conversion efficiency of the cells.

[0003] In the prior art, the passivated contact structure of solar cells usually includes a passivation layer and a doped polysilicon layer that are sequentially stacked on the surface of a silicon substrate. The metal electrodes of the solar cells are in contact with the doped polysilicon layer to achieve the passivated contact of the solar cells. However, the passivated contact structure of solar cells is usually set as a combination of a single-layer doped polysilicon layer and a single-layer passivation layer. In the preparation process of solar cells, the introduced impurities are likely to diffuse into the interior of the silicon substrate, resulting in poor passivation effect of the passivated contact structure of solar cells and affecting the efficiency of solar cells. Summary of the Invention

[0004] The present invention provides a passivated contact structure for a solar cell, aiming to solve the problem that the passivated contact structure of the solar cell in the prior art has a poor passivation effect and affects the cell efficiency.

[0005] The present invention is implemented as follows. A passivated contact structure for a solar cell is provided, which includes a first passivation layer, a first doped polysilicon layer, a first barrier layer, and a second doped polysilicon layer that are sequentially stacked on the surface of a silicon substrate. The doping polarity of the first doped polysilicon layer is the same as that of the second doped polysilicon layer; wherein, the thickness of the first passivation layer is greater than the thickness of the first barrier layer.

[0006] Preferably, the ratio of the thickness of the first passivation layer to the thickness of the first barrier layer is 1 to 10 and not equal to 1.

[0007] Preferably, the ratio of the thickness of the first passivation layer to the thickness of the first barrier layer is 1 to 4 and not equal to 1.

[0008] Preferably, the ratio of the thickness of the first passivation layer to the thickness of the first barrier layer is 1 to 2 and not equal to 1.

[0009] Preferably, the thickness of the first passivation layer is 0.5 to 5 nanometers, and the thickness of the first barrier layer is 0.2 to 4.5 nanometers.

[0010] Preferably, the first passivation layer is provided with holes, and the first doped polysilicon layer contacts the silicon substrate through the holes in the first passivation layer.

[0011] Preferably, the first barrier layer is provided with holes, and the second doped polysilicon layer passes through the holes in the first barrier layer and contacts the first doped polysilicon layer.

[0012] Preferably, both the first passivation layer and the first barrier layer are provided with holes, and the hole density of the first passivation layer is less than that of the first barrier layer.

[0013] Preferably, both the first passivation layer and the first barrier layer are provided with holes, and the average pore diameter of the first passivation layer is less than that of the first barrier layer.

[0014] Preferably, the first passivation layer includes one or a combination of silicon oxide containing boron, phosphorus or gallium, silicon oxynitride containing boron, phosphorus or gallium, and silicon nitride containing boron, phosphorus or gallium.

[0015] Preferably, the first barrier layer includes one or a combination of silicon oxide containing boron, phosphorus or gallium, silicon oxynitride containing boron, phosphorus or gallium, silicon nitride containing boron, phosphorus or gallium, oxygen-rich silicon containing boron, phosphorus or gallium, and nitrogen-rich silicon containing boron, phosphorus or gallium.

[0016] Preferably, the oxygen content of the oxygen-rich silicon is 1×10 19 atoms / cm 3 or more.

[0017] Preferably, the nitrogen content of the nitrogen-rich silicon is 1×10 19 atoms / cm 3 or more.

[0018] Preferably, the first passivation layer, the first doped polysilicon layer, the first barrier layer, and the second doped polysilicon layer are all doped with Group IIIA or Group VA elements; the doping concentration of the second doped polysilicon layer is greater than or equal to that of the first doped polysilicon layer.

[0019] Preferably, the doping concentration of the first passivation layer is less than or equal to that of the first barrier layer.

[0020] Preferably, the thickness of the first doped polysilicon layer is greater than that of the second doped polysilicon layer.

[0021] Preferably, the ratio of the thickness of the first doped polysilicon layer to the thickness of the second doped polysilicon layer is 1 to 50.

[0022] Preferably, the ratio of the thickness of the first doped polysilicon layer to the thickness of the second doped polysilicon layer is 2 to 50.

[0023] Preferably, the ratio of the thickness of the first doped polysilicon layer to the thickness of the second doped polysilicon layer is 5 to 50.

[0024] Preferably, the ratio of the thickness of the first doped polysilicon layer to the thickness of the second doped polysilicon layer is 10 to 50.

[0025] Preferably, the thickness of the first doped polysilicon layer is 30 to 350 nanometers, and the thickness of the second doped polysilicon layer is 5 to 150 nanometers.

[0026] Preferably, it further includes:

[0027] A second barrier layer, disposed on a side of the second doped polysilicon layer facing away from the silicon substrate.

[0028] Preferably, the thickness of the second barrier layer is less than or equal to the thickness of the first barrier layer.

[0029] Preferably, it further includes:

[0030] A third doped polysilicon layer, disposed on a side of the second barrier layer facing away from the silicon substrate, and the doping polarity of the third doped polysilicon layer is the same as or opposite to the doping polarity of the second doped polysilicon layer.

[0031] Preferably, it further includes:

[0032] A third barrier layer, disposed on a side of the third doped polysilicon layer facing away from the silicon substrate.

[0033] Preferably, it further includes:

[0034] A fourth doped polysilicon layer, disposed on a side of the third barrier layer facing away from the silicon substrate, and the doping polarity of the fourth doped polysilicon layer is the same as or opposite to the doping polarity of the second doped polysilicon layer.

[0035] Preferably, the thickness of the third barrier layer is less than or equal to the thickness of the second barrier layer.

[0036] Preferably, both the first barrier layer and the second doped polysilicon layer are discontinuously disposed on the first doped polysilicon layer.

[0037] Preferably, the thicknesses of the first doped polysilicon layer, the second doped polysilicon layer, the third doped polysilicon layer, and the fourth doped polysilicon layer decrease in sequence.

[0038] Preferably, it further includes:

[0039] A first metal electrode disposed on the second doped polysilicon layer, the first metal electrode being in contact with the second doped polysilicon layer.

[0040] Preferably, the first metal electrode passes through the second doped polysilicon layer, the first barrier layer and is in contact with the first doped polysilicon layer.

[0041] Preferably, the width of the first metal electrode in the region of the first doped polysilicon layer is less than the width of the first metal electrode in the region of the second doped polysilicon layer.

[0042] The present invention also provides a solar cell, comprising a silicon substrate, the silicon substrate including a light-facing surface and a backlight surface disposed opposite to the light-facing surface, the solar cell passivation contact structure as described above being provided on the light-facing surface and / or the backlight surface.

[0043] Preferably, the solar cell passivation contact structure is locally provided on the light-facing surface.

[0044] Preferably, a second passivation layer and a fifth doped polysilicon layer provided on a side of the second passivation layer away from the silicon substrate are provided in a region of the light-facing surface where the solar cell passivation contact structure is not provided, and the doping polarity of the fifth doped polysilicon layer is the same as the doping polarity of the first doped polysilicon layer.

[0045] Preferably, the solar cell is a back-contact solar cell, a P region and an N region are provided on the backlight surface of the back-contact solar cell, and the solar cell passivation contact structure is provided in both the P region and the N region; the first doped polysilicon layer of the solar cell passivation contact structure in the P region is P-type doped polysilicon, and the first doped polysilicon layer of the solar cell passivation contact structure in the N region is N-type doped polysilicon.

[0046] Preferably, the solar cell passivation contact structure is locally provided on the backlight surface.

[0047] Preferably, a third passivation layer and a sixth doped polysilicon layer provided on a side of the third passivation layer away from the silicon substrate are provided in a region of the backlight surface where the solar cell passivation contact structure is not provided, and the doping polarity of the sixth doped polysilicon layer is opposite to the doping polarity of the first doped polysilicon layer.

[0048] Preferably, an isolation region is provided between the sixth doped polysilicon layer and the first doped polysilicon layer.

[0049] The present invention also provides a battery module, comprising the above-mentioned solar cell.

[0050] The present invention also provides a photovoltaic system, comprising the above-mentioned battery module.

[0051] The present invention provides a passivated contact structure for a solar cell, which includes a first passivation layer, a first doped polysilicon layer, a first barrier layer, and a second doped polysilicon layer that are sequentially stacked on the surface of a silicon substrate. By adding a first barrier layer and a second doped polysilicon layer on the surface of the first doped polysilicon layer, and utilizing the combined blocking effect of the first passivation layer and the first barrier layer, excessive impurities can be prevented from diffusing into the interior of the silicon substrate, reducing the inward diffusion of impurities into the silicon substrate, significantly improving the passivation effect of the solar cell, and thus enhancing the cell efficiency. The first barrier layer and the second doped polysilicon layer can also cooperate to achieve a certain passivation effect. Moreover, a first barrier layer that is thinner than the first passivation layer is provided between the second doped polysilicon layer and the first doped polysilicon layer. The first barrier layer can allow the formation of the second doped polysilicon layer and the first doped polysilicon layer while playing a certain role in mutual isolation, creating a doping concentration difference between the two doped polysilicon layers, and further improving the passivation effect of the passivated contact structure of the solar cell and enhancing the efficiency of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a partial structural schematic diagram of a passivated contact structure for a solar cell provided in Embodiment 1 of the present invention;

[0053] Figure 2 It is a schematic diagram of a passivated contact structure for a solar cell provided in Embodiment 1 of the present invention;

[0054] Figure 3 It is a schematic diagram of another passivated contact structure for a solar cell provided in Embodiment 1 of the present invention;

[0055] Figure 4 It is a schematic diagram of yet another passivated contact structure for a solar cell provided in Embodiment 1 of the present invention;

[0056] Figure 5 is Figure 4 a partial schematic diagram of the passivated contact structure of the solar cell shown;

[0057] Figure 6 It is a partial structural schematic diagram of a passivated contact structure for a solar cell provided in Embodiment 2 of the present invention;

[0058] Figure 7 It is a schematic diagram of a passivated contact structure for a solar cell provided in Embodiment 2 of the present invention;

[0059] Figure 8 It is a schematic diagram of yet another passivated contact structure for a solar cell provided in Embodiment 2 of the present invention;

[0060] Figure 9Partial structural schematic diagram of a passivated contact structure for a solar cell provided in Embodiment III of the present invention;

[0061] Figure 10 Schematic diagram of a passivated contact structure for a solar cell provided in Embodiment III of the present invention;

[0062] Figure 11 Schematic diagram of another passivated contact structure for a solar cell provided in Embodiment III of the present invention;

[0063] Figure 12 Partial structural schematic diagram of a passivated contact structure for a solar cell provided in Embodiment IV of the present invention;

[0064] Figure 13 Schematic diagram of the structure of a solar cell provided in Embodiment V of the present invention;

[0065] Figure 14 Schematic diagram of the structure of a solar cell provided in Embodiment VI of the present invention;

[0066] Figure 15 Schematic diagram of the structure of a solar cell provided in Embodiment VII of the present invention;

[0067] Figure 16 Schematic diagram of the structure of a solar cell provided in Embodiment VIII of the present invention;

[0068] Figure 17 Top view structural schematic diagram of a solar cell provided in Embodiment IX of the present invention;

[0069] Figure 18 is the sectional view along the Figure 17 A - A direction in;

[0070] Figure 19 is the sectional view along the Figure 17 B - B direction in. Detailed implementation manners

[0071] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to 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 used to limit the present invention.

[0072] The present invention provides a passivated contact structure for a solar cell, which includes a first passivation layer, a first doped polysilicon layer, a first barrier layer, and a second doped polysilicon layer that are sequentially stacked on the surface of a silicon substrate. By adding the first barrier layer and the second doped polysilicon layer on the surface of the first doped polysilicon layer, and using the combined blocking effect of the first passivation layer and the first barrier layer, excessive impurities can be prevented from diffusing into the interior of the silicon substrate, reducing the inward diffusion of impurities into the silicon substrate, significantly improving the passivation effect of the solar cell, and thus enhancing the cell efficiency; the first barrier layer and the second doped polysilicon layer can also cooperate to achieve a certain passivation effect, and a first barrier layer that is thinner than the first passivation layer is provided between the second doped polysilicon layer and the first doped polysilicon layer. The first barrier layer can allow the formation of the second doped polysilicon layer and the first doped polysilicon layer while playing a certain mutual blocking role, forming a doping concentration difference between the two doped polysilicon layers, which can further improve the passivation effect of the passivated contact structure of the solar cell and enhance the efficiency of the solar cell.

[0073] Embodiment 1

[0074] Please refer to Figures 1-4 , an embodiment of the present invention provides a passivated contact structure for a solar cell, which includes a first passivation layer 1, a first doped polysilicon layer 2, a first barrier layer 3, and a second doped polysilicon layer 4 that are sequentially stacked on the surface of a silicon substrate 10. The doping polarity of the first doped polysilicon layer 2 is the same as that of the second doped polysilicon layer 4; wherein, the thickness d4 of the first passivation layer 1 is greater than or equal to the thickness d5 of the first barrier layer 3.

[0075] In the embodiment of the present invention, the silicon substrate 10 can be a P-type silicon substrate or an N-type silicon substrate. Among them, the surface of the silicon substrate 10 can be the light-facing surface or the backlight surface of the solar cell.

[0076] In the embodiment of the present invention, a passivated contact structure for a solar cell is provided. By stacking the first barrier layer 3 and the second doped polysilicon layer 4, and using the combined blocking effect of the first passivation layer 1 and the first barrier layer 3, excessive impurities can be prevented from diffusing into the interior of the silicon substrate 10, reducing the inward diffusion of impurities into the silicon substrate 10, significantly improving the passivation effect of the solar cell, and thus enhancing the cell efficiency; at the same time, the first barrier layer 3 and the second doped polysilicon layer 4 can also cooperate to achieve a certain passivation effect. The first barrier layer 3 is thinner than the first passivation layer 1. The first barrier layer 3 can allow the formation of the second doped polysilicon layer 4 and the first doped polysilicon layer 2 while the first barrier layer 3 can play a certain mutual blocking role, forming a doping concentration difference between the second doped polysilicon layer 4 and the first doped polysilicon layer 2, which can further improve the passivation effect of the passivated contact structure of the solar cell and enhance the efficiency of the solar cell.

[0077] In addition, in practical applications, the passivation effect can be further optimized by adjusting the doping concentration and thickness of the first doped polysilicon layer 2 and the second doped polysilicon layer 4, so that the passivation contact structure of the solar cell has a better passivation effect, which can effectively improve the efficiency of the solar cell.

[0078] In the embodiment of the present invention, the thickness d4 of the first passivation layer 1 is greater than the thickness d5 of the first barrier layer 3, that is, the first passivation layer 1 closer to the silicon substrate 10 is thicker, which can further improve the passivation effect of the passivation contact structure of the solar cell and effectively improve the efficiency of the solar cell. Of course, in some other possible embodiments, the thickness d4 of the first passivation layer 1 may also be equal to or less than the thickness d5 of the first barrier layer 3.

[0079] In this embodiment, the doping polarities of the first doped polysilicon layer 2 and the second doped polysilicon layer 4 are both P-type or N-type. For example, both the first doped polysilicon layer 2 and the second doped polysilicon layer 4 may be doped with boron elements, or both the first doped polysilicon layer 2 and the second doped polysilicon layer 4 may be doped with phosphorus elements.

[0080] As an embodiment of the present invention, the first passivation layer 1, the first doped polysilicon layer 2, the first barrier layer 3, and the second doped polysilicon layer 4 are all doped with group IIIA or group VA elements; the doping concentration of the first doped polysilicon layer 2 is less than the doping concentration of the second doped polysilicon layer 4.

[0081] In this embodiment, the doping concentration of the second doped polysilicon layer 4 may be greater than the doping concentration of the first doped polysilicon layer 2, or the doping concentration of the second doped polysilicon layer 4 may be equal to the doping concentration of the first doped polysilicon layer 2. In addition, in some other embodiments, the doping concentration of the second doped polysilicon layer 4 may also be less than the doping concentration of the first doped polysilicon layer 2.

[0082] As a preferred embodiment of the present invention, the doping concentration of the second doped polysilicon layer 4 is greater than the doping concentration of the first doped polysilicon layer 2.

[0083] In this embodiment, since the doping concentration of the second doped polysilicon layer 4 is greater than the doping concentration of the first doped polysilicon layer 2, the second doped polysilicon layer 4 and the first doped polysilicon layer 2 form a high-low junction to provide field-effect passivation; moreover, the doping concentration of the second doped polysilicon layer 4 is relatively higher than that of the first doped polysilicon layer 2, which is beneficial to forming a good ohmic contact between the second doped polysilicon layer 4 and the first metal electrode 11, reducing current loss, and improving the cell efficiency.

[0084] As an embodiment of the present invention, the doping concentration of the first passivation layer 1 is less than or equal to the doping concentration of the first barrier layer 3.

[0085] In this embodiment, the doping concentration of the first passivation layer 1 may be less than that of the first barrier layer 3, or the doping concentration of the first passivation layer 1 may be equal to that of the first barrier layer 3. In some other embodiments, the doping concentration of the first passivation layer 1 may also be greater than that of the first barrier layer 3.

[0086] As a preferred embodiment of the present invention, the doping concentration of the first passivation layer 1 is less than that of the first barrier layer 3, which is beneficial to improving the ability of the first barrier layer 3 to block impurities from entering the silicon substrate 10.

[0087] As an embodiment of the present invention, the ratio of the thickness d4 of the first passivation layer 1 to the thickness d5 of the first barrier layer 3 is 1 to 10 and not equal to 1.

[0088] In this embodiment, the ratio of the thickness d4 of the first passivation layer 1 to the thickness d5 of the first barrier layer 3 is greater than 1 and less than or equal to 10. This can not only ensure good impurity-blocking effects of the first passivation layer 1 and the first barrier layer 3, but also enable the passivation contact structure of the solar cell to have a good passivation effect, and is also convenient for the preparation of the first passivation layer 1 and the first barrier layer 3.

[0089] Specifically, the thickness d4 of the first passivation layer 1 and the thickness d5 of the first barrier layer 3 can be flexibly set, as long as the thickness d4 of the first passivation layer 1 is greater than the thickness d5 of the first barrier layer 3. The ratio of the thickness d4 of the first passivation layer 1 to the thickness d5 of the first barrier layer 3 can be: 1.01, or 1.5, or 2.0, or 2.4, or 3.0, or 3.5, or 4, or 4.5, or 5, or 5.5, or 6, or 7, or 8, or 9, or 10.

[0090] As an embodiment of the present invention, the ratio of the thickness d4 of the first passivation layer 1 to the thickness d5 of the first barrier layer 3 is 1 to 4 and not equal to 1.

[0091] In this embodiment, the ratio of the thickness d4 of the first passivation layer 1 to the thickness d5 of the first barrier layer 3 is greater than 1 and less than or equal to 4, which can not only ensure good impurity-blocking effects and good passivation effects of the first passivation layer 1 and the first barrier layer 3, but also be more convenient for the preparation of the first passivation layer 1 and the first barrier layer 3.

[0092] As an embodiment of the present invention, the ratio of the thickness d4 of the first passivation layer 1 to the thickness d5 of the first barrier layer 3 is 1 to 2 and not equal to 1.

[0093] In this embodiment, the ratio of the thickness d4 of the first passivation layer 1 to the thickness d5 of the first barrier layer 3 is greater than 1 and less than or equal to 2, further reducing the thickness difference between the first passivation layer 1 and the first barrier layer 3, making it more convenient to prepare the first passivation layer 1 and the first barrier layer 3, and achieving good impurity blocking effect and good passivation effect of the first passivation layer 1 and the first barrier layer 3.

[0094] As an embodiment of the present invention, the thickness d4 of the first passivation layer 1 is 0.5 - 5 nanometers, and the thickness d5 of the first barrier layer 3 is 0.2 - 4.5 nanometers. In addition, the thickness d4 of the first passivation layer 1 and the thickness d5 of the first barrier layer 3 are not limited to this range, and the thicknesses of the first passivation layer 1 and the first barrier layer 3 can be flexibly set according to needs.

[0095] In this embodiment, on the premise that the thickness d4 of the first passivation layer 1 is greater than the thickness d5 of the first barrier layer 3, the thickness d4 of the first passivation layer 1 can be: 0.5 nanometers, or 1 nanometer, or 1.5 nanometers, or 2.0 nanometers, or 2.5 nanometers, or 2.8 nanometers, or 3.0 nanometers, or 3.2 nanometers, or 3.5 nanometers, or 3.8 nanometers, or 4.0 nanometers, or 4.2 nanometers, or 4.5 nanometers, or 5 nanometers.

[0096] In this embodiment, the thickness d5 of the first barrier layer 3 can be: 0.2 nanometers, or 0.5 nanometers, or 1 nanometer, or 1.5 nanometers, or 2.0 nanometers, or 2.5 nanometers, or 2.8 nanometers, or 3.0 nanometers, or 3.2 nanometers, or 3.5 nanometers, or 3.8 nanometers, or 4.0 nanometers, or 4.2 nanometers, or 4.5 nanometers.

[0097] As an embodiment of the present invention, the first passivation layer 1 is provided with holes (not shown), and the first doped polysilicon layer 2 contacts the silicon substrate 10 through the holes on the first passivation layer 1.

[0098] In this embodiment, the holes on the first passivation layer 1 vertically penetrate the first passivation layer 1. An inner diffusion layer is also provided inside the silicon substrate 10, and the first doped polysilicon layer 2 contacts the inner diffusion layer inside the silicon substrate 10 through the holes on the first passivation layer 1. The first doped polysilicon layer 2 contacts the silicon substrate 10 by using the holes on the first passivation layer 1, which is beneficial to the contact between the first doped polysilicon layer 2 and the silicon substrate 10, reduces current loss, and improves the battery conversion efficiency.

[0099] As an embodiment of the present invention, the first barrier layer 3 is provided with holes, and the second doped polysilicon layer 4 passes through the holes on the first barrier layer 3 and contacts the first doped polysilicon layer 2.

[0100] In this embodiment, the holes in the first barrier layer 3 vertically penetrate the first barrier layer 3. The second doped polysilicon layer 4 contacts the first doped polysilicon layer 2 by using the holes in the first barrier layer 3, which is beneficial to the contact between the second doped polysilicon layer 4 and the first doped polysilicon layer 2, reduces current loss, and improves the battery conversion efficiency.

[0101] Among them, the holes in the first passivation layer 1 and the first barrier layer 3 can be formed by chemical etching, dry etching, thermal diffusion shock or other methods, which are prepared according to actual usage needs and are not specifically limited here. When observing the first passivation layer 1 and the first barrier layer 3 from a top view angle, the first passivation layer 1 and the first barrier layer 3 present a porous structure, while when observing the first passivation layer 1 and the first barrier layer 3 from a cross-sectional angle, the first passivation layer 1 and the first barrier layer 3 show a multi-channel structure. Optionally, the aperture of the holes in the first passivation layer 1 and the first barrier layer 3 is less than 10 μm.

[0102] As an embodiment of the present invention, both the first passivation layer 1 and the first barrier layer 3 are provided with holes, and the hole density of the first passivation layer 1 is less than the hole density of the first barrier layer 3.

[0103] In this embodiment, the hole density of the first passivation layer 1 is less than the hole density of the first barrier layer 3, which can be understood as that the number of holes in the first passivation layer 1 per unit area is less than the number of holes in the first barrier layer 3 per unit area. Since the hole density of the first passivation layer 1 is less than the hole density of the first barrier layer 3, the conductivity of the first passivation layer 1 and the first barrier layer 3 can be enhanced in sequence, and it is beneficial to improve the gettering effect of the silicon substrate 10, which is beneficial to improving the battery efficiency.

[0104] As an embodiment of the present invention, both the first passivation layer 1 and the first barrier layer 3 are provided with holes, and the average aperture of the holes in the first passivation layer 1 is less than the average aperture of the holes in the first barrier layer 3.

[0105] Among them, the apertures of the holes in the first passivation layer 1 can be equal or unequal; similarly, the apertures of the holes in the first barrier layer 3 can be equal or unequal. The average aperture of the holes in the first passivation layer 1 can be understood as the average aperture of all the holes in the first passivation layer 1; the average aperture of the holes in the first barrier layer 3 can be understood as the average aperture of all the holes in the first barrier layer 3. By setting the average aperture of the holes in the first passivation layer 1 to be less than the average aperture of the holes in the first barrier layer 3, it is beneficial to improve the back passivation effect of the first passivation layer 1 on the silicon substrate 10, which is beneficial to improving the battery efficiency.

[0106] As an embodiment of the present invention, the first passivation layer 1 includes one or a combination of silicon oxide containing boron, phosphorus or gallium, silicon oxynitride containing boron, phosphorus or gallium, and silicon nitride containing boron, phosphorus or gallium.

[0107] In this embodiment, the first passivation layer 1 can be silicon oxide containing boron, phosphorus or gallium, or silicon oxynitride containing boron, phosphorus or gallium, or silicon nitride containing boron, phosphorus or gallium; alternatively, the first passivation layer 1 can be any combination of silicon oxide containing boron, phosphorus or gallium, silicon oxynitride containing boron, phosphorus or gallium, and silicon nitride containing boron, phosphorus or gallium. Among them, using the above materials for the first passivation layer 1 can not only achieve a good impurity blocking effect of the first passivation layer 1, but also achieve a good passivation effect.

[0108] As an embodiment of the present invention, the first barrier layer 3 includes one or a combination of silicon oxide containing boron, phosphorus or gallium, silicon oxynitride containing boron, phosphorus or gallium, silicon nitride containing boron, phosphorus or gallium, oxygen-rich silicon containing boron, phosphorus or gallium, and nitrogen-rich silicon containing boron, phosphorus or gallium.

[0109] In this embodiment, the first barrier layer 3 can be silicon oxide containing boron, phosphorus or gallium, or silicon oxynitride containing boron, phosphorus or gallium, or silicon nitride containing boron, phosphorus or gallium, or oxygen-rich silicon containing boron, phosphorus or gallium, or nitrogen-rich silicon containing boron, phosphorus or gallium; the first barrier layer 3 can also be any combination of silicon oxide containing boron, phosphorus or gallium, silicon oxynitride containing boron, phosphorus or gallium, silicon nitride containing boron, phosphorus or gallium, oxygen-rich silicon containing boron, phosphorus or gallium, and nitrogen-rich silicon containing boron, phosphorus or gallium. Among them, using the above materials for the first barrier layer 3 can not only achieve a good impurity blocking effect of the first barrier layer 3, but also achieve a relatively good passivation effect.

[0110] As an embodiment of the present invention, the oxygen content of the oxygen-rich silicon is 1×10 19 atoms / cm 3 or more.

[0111] In this embodiment, when the first barrier layer 3 includes oxygen-rich silicon containing boron, phosphorus or gallium, the oxygen content of the oxygen-rich silicon is 1×10 19 atoms / cm 3 or more, which can improve the impurity blocking effect of the first barrier layer 3.

[0112] As an embodiment of the present invention, when the first barrier layer 3 includes nitrogen-rich silicon containing boron, phosphorus or gallium, the nitrogen content of the nitrogen-rich silicon is 1×10 19 atoms / cm 3 or more, which can improve the impurity blocking effect of the first barrier layer 3.

[0113] As an embodiment of the present invention, the thickness d1 of the first doped polysilicon layer 2 is greater than the thickness d2 of the second doped polysilicon layer 4.

[0114] In this embodiment, the thickness d1 of the first doped polysilicon layer 2 is greater than the thickness d2 of the second doped polysilicon layer 4, so that the doped polysilicon layer closer to the silicon substrate 10 is thicker, which is beneficial to further improving the passivation effect of the passivated contact structure of the solar cell.

[0115] Of course, in some other embodiments, the thickness d1 of the first doped polysilicon layer 2 may also be less than or equal to the thickness d2 of the second doped polysilicon layer 4.

[0116] As an embodiment of the present invention, the ratio of the thickness d1 of the first doped polysilicon layer 2 to the thickness d2 of the second doped polysilicon layer 4 is 1 to 50.

[0117] In this embodiment, the ratio of the thickness d1 of the first doped polysilicon layer 2 to the thickness d2 of the second doped polysilicon layer 4 is greater than or equal to 1 and less than or equal to 50, which can ensure a good passivation effect of the passivated contact structure of the solar cell.

[0118] Specifically, the thickness d1 of the first doped polysilicon layer 2 and the thickness d2 of the second doped polysilicon layer 4 can be specifically set flexibly, as long as the ratio of the thickness d1 of the first doped polysilicon layer 2 to the thickness d2 of the second doped polysilicon layer 4 is within 1 to 50. For example, the ratio of the thickness d1 of the first doped polysilicon layer 2 to the thickness d2 of the second doped polysilicon layer 4 can be: 1, or 3, or 5, or 6, or 8, or 10, or 12, or 14, or 15, or 16, or 17, or 19, or 20, or 22, or 25, or 28, or 30, or 32, or 35, or 38, or 40, or 42, or 46, or 48, or 50.

[0119] As an embodiment of the present invention, the ratio of the thickness d1 of the first doped polysilicon layer 2 to the thickness d2 of the second doped polysilicon layer 4 is 2 to 50.

[0120] In this embodiment, the ratio of the thickness d1 of the first doped polysilicon layer 2 to the thickness d2 of the second doped polysilicon layer 4 is greater than or equal to 2 and less than or equal to 50, so that the difference between the thickness d1 of the first doped polysilicon layer 2 and the thickness d2 of the second doped polysilicon layer 4 is within a better range, which can ensure a better passivation effect of the passivated contact structure of the solar cell and is more convenient for the preparation of the first doped polysilicon layer 2 and the second doped polysilicon layer 4.

[0121] As an embodiment of the present invention, the ratio of the thickness d1 of the first doped polysilicon layer 2 to the thickness d2 of the second doped polysilicon layer 4 is 5 to 50.

[0122] In this embodiment, the ratio of the thickness d1 of the first doped polysilicon layer 2 to the thickness d2 of the second doped polysilicon layer 4 is greater than or equal to 5 and less than or equal to 50. In this way, the difference between the thickness d1 of the first doped polysilicon layer 2 and the thickness d2 of the second doped polysilicon layer 4 is larger, which can further improve the passivation effect of the passivated contact structure of the solar cell.

[0123] As an embodiment of the present invention, the ratio of the thickness of the first doped polysilicon layer 2 to the thickness of the second doped polysilicon layer 4 is 10 to 50.

[0124] In this embodiment, the ratio of the thickness d1 of the first doped polysilicon layer 2 to the thickness d2 of the second doped polysilicon layer 4 is greater than or equal to 10 and less than or equal to 50. By further increasing the difference between the thickness d1 of the first doped polysilicon layer 2 and the thickness d2 of the second doped polysilicon layer 4, the passivation effect of the passivated contact structure of the solar cell can be further improved.

[0125] As an embodiment of the present invention, the thickness d1 of the first doped polysilicon layer 2 is 30 to 350 nanometers, and the thickness d2 of the second doped polysilicon layer 4 is 5 to 150 nanometers.

[0126] In this embodiment, the thickness d1 of the first doped polysilicon layer 2 can be any value within the range of 30 to 350 nanometers, and the thickness d2 of the second doped polysilicon layer 4 can be any value within the range of 5 to 150 nanometers. For example, the thickness d1 of the first doped polysilicon layer 2 can be 30 nanometers, and the thickness d2 of the second doped polysilicon layer 4 can be 5 nanometers; or, the thickness d1 of the first doped polysilicon layer 2 can be 300 nanometers, and the thickness d2 of the second doped polysilicon layer 4 can be 30 nanometers; or, the thickness d1 of the first doped polysilicon layer 2 can be 350 nanometers, and the thickness d2 of the second doped polysilicon layer 4 can be 150 nanometers.

[0127] As an embodiment of the present invention, both the first barrier layer 3 and the second doped polysilicon layer 4 are in a continuous and full-surface structure covering the first doped polysilicon layer 2, that is, the first barrier layer 3 and the second doped polysilicon layer 4 cover the first doped polysilicon layer 2 entirely, and full-surface passivation can be achieved.

[0128] Please refer to Figure 2 , the passivated contact structure of the solar cell in this embodiment further includes:

[0129] A first metal electrode 11 disposed on the second doped polysilicon layer 4, and the first metal electrode 11 is in contact with the second doped polysilicon layer 4.

[0130] In this embodiment, since the first doped polysilicon layer 2 and the second doped polysilicon layer 4 have the same doping polarity, the first metal electrode 11 directly contacts the second doped polysilicon layer 4, and there is no pre-set opening between the second doped polysilicon layer 4 and the first barrier layer 3, so that the first doped polysilicon layer 2 and the second doped polysilicon layer 4 have a good barrier effect.

[0131] Please refer to Figure 3 As another embodiment of the present invention, the first metal electrode 11 passes through the second doped polysilicon layer 4 and the first barrier layer 3 and contacts the first doped polysilicon layer 2 .

[0132] In this embodiment, during the metallization process of the first metal electrode 11, the first metal electrode 11 may pass through the second doped polysilicon layer 4 and the first barrier layer 3 to contact the first doped polysilicon layer 2, so that the first metal electrode 11 is simultaneously in contact with the second doped polysilicon layer 4, the first barrier layer 3, and the first doped polysilicon layer 2. Because there are no pre-set openings between the second doped polysilicon layer 4 and the first barrier layer 3, the first metal electrode 11 is in close contact with the second doped polysilicon layer 4 and the first barrier layer 3, which can also ensure that the second doped polysilicon layer 4 and the first barrier layer 3 effectively block impurities.

[0133] Please refer to Figure 4 and Figure 5 As an embodiment of the present invention, the width of the first metal electrode 11 located in the first doped polysilicon layer 2 is smaller than the width of the first metal electrode 11 located in the second doped polysilicon layer 4.

[0134] The width of the first metal electrode 11 in the region of the first doped polysilicon layer 2 can be any width of the first metal electrode 11 in the region of the first doped polysilicon layer 2 along the horizontal direction L; the width of the first metal electrode 11 in the region of the second doped polysilicon layer 4 can be any width of the first metal electrode 11 in the region of the second doped polysilicon layer 4 along the horizontal direction L. Preferably, the width of the first metal electrode 11 in the region of the first doped polysilicon layer 2 is the width W1 of the first metal electrode 11 in the region of the first doped polysilicon layer 2, away from the surface of the first passivation layer 1, along the horizontal direction L; the width of the first metal electrode 11 in the region of the second doped polysilicon layer 4 is the width W2 of the first metal electrode 11 in the region of the second doped polysilicon layer 4, away from the surface of the first passivation layer 1, along the horizontal direction L.

[0135] In this embodiment, due to the blocking effect of the second doped polysilicon layer 4 and the first barrier layer 3, the penetration depth of the first metal electrode 11 can be blocked, such that the first metal electrode 11 gradually decreases from the surface of the second doped polysilicon layer 4 facing away from the first passivation layer 1 towards the first doped polysilicon layer 2. In this way, the first metal electrode 11 can be blocked from entering and penetrating the first passivation layer 1, preventing the first metal electrode 11 from directly contacting the silicon substrate 10.

[0136] Embodiment Two

[0137] Please refer to Figure 6 , on the basis of Embodiment One, the passivated contact structure of the solar cell in this embodiment further includes:

[0138] A second barrier layer 5, disposed on the side of the second doped polysilicon layer 4 facing away from the silicon substrate 10.

[0139] In this embodiment, by disposing the second barrier layer 5 on the surface of the second doped polysilicon layer 4 facing away from the silicon substrate 10, the second barrier layer 5 can be utilized to block the inward diffusion of impurities into the silicon substrate 10. Further blocking the inward diffusion of impurities into the silicon substrate 10 can further improve the passivation effect of the passivated contact structure of the solar cell.

[0140] As an embodiment of the present invention, the thickness of the second barrier layer 5 is less than or equal to the thickness of the first barrier layer 3.

[0141] In this embodiment, the thickness of the second barrier layer 5 can be less than or equal to the thickness of the first barrier layer 3. In some other embodiments, the thickness of the second barrier layer 5 can also be greater than the thickness of the first barrier layer 3. Among them, the material of the second barrier layer 5 can be the same as or different from the material of the first barrier layer 3.

[0142] As an embodiment of the present invention, it further includes:

[0143] A third doped polysilicon layer 6, disposed on the side of the second barrier layer 5 facing away from the silicon substrate 10, and the doping polarity of the third doped polysilicon layer 6 is the same as or opposite to the doping polarity of the second doped polysilicon layer 4.

[0144] In this embodiment, by adding the second barrier layer 5 and the third doped polysilicon layer 6, and using the second barrier layer 5, the first barrier layer 3, and the first passivation layer 1 together to block the inward diffusion of impurities into the silicon substrate 10, the passivation effect of the passivated contact structure of the solar cell can be further improved; moreover, the third doped polysilicon layer 6 can be utilized to further enhance the passivation effect of the passivated contact structure of the solar cell.

[0145] Among them, the doping polarity of the third doped polysilicon layer 6 can be the same as or opposite to the doping polarity of the second doped polysilicon layer 4.

[0146] Please refer to Figure 7 , the doping polarity of the third doped polysilicon layer 6 is the same as that of the second doped polysilicon layer 4, that is, the doping polarities of the third doped polysilicon layer 6, the second doped polysilicon layer 4, and the first doped polysilicon layer 2 are all P-type or N-type. At this time, there is no need to set an opening on the third doped polysilicon layer 6, and the first metal electrode 11 can be in contact with the third doped polysilicon layer 6. Of course, the first metal electrode 11 can also pass through the third doped polysilicon layer 6 and be in contact with the second doped polysilicon layer 4 or the first doped polysilicon layer 2.

[0147] Please refer to Figure 8 , the doping polarity of the third doped polysilicon layer 6 is opposite to that of the second doped polysilicon layer 4, that is, if the doping polarities of the second doped polysilicon layer 4 and the first doped polysilicon layer 2 are P-type, then the doping polarity of the third doped polysilicon layer 6 is N-type; or, if the doping polarities of the second doped polysilicon layer 4 and the first doped polysilicon layer 2 are N-type, then the doping polarity of the third doped polysilicon layer 6 is P-type. At this time, an opening 100 is provided in the third doped polysilicon layer 6 and the second barrier layer 5, and the first metal electrode 11 passes through the opening 100 and is in contact with the second doped polysilicon layer 4 or the first doped polysilicon layer 2.

[0148] Embodiment 3

[0149] Please refer to Figure 9 , on the basis of Embodiment 2, the passivated contact structure of the solar cell in this embodiment further includes:

[0150] A third barrier layer 7, provided on the side of the third doped polysilicon layer 6 facing away from the silicon substrate 10.

[0151] In this embodiment, by providing the third barrier layer 7 on the surface of the third doped polysilicon layer 6 facing away from the silicon substrate 10, the third barrier layer 7 can be used to block the inward diffusion of impurities into the silicon substrate 10. Further blocking the inward diffusion of impurities into the silicon substrate 10 can further improve the passivation effect of the passivated contact structure of the solar cell.

[0152] As an embodiment of the present invention, it further includes:

[0153] A fourth doped polysilicon layer 8, provided on the side of the third barrier layer 7 facing away from the silicon substrate 10, and the doping polarity of the fourth doped polysilicon layer 8 is the same as or opposite to that of the second doped polysilicon layer 4.

[0154] In this embodiment, by adding the third barrier layer 7 and the fourth doped polysilicon layer 8, and using the third barrier layer 7, the second barrier layer 5, the first barrier layer 3, and the first passivation layer 1 to jointly prevent impurities from diffusing into the silicon substrate 10, the passivation effect of the passivated contact structure of the solar cell can be further improved; moreover, the fourth doped polysilicon layer 8 can be used to further enhance the passivation effect of the passivated contact structure of the solar cell.

[0155] Among them, the doping polarity of the fourth doped polysilicon layer 8 is the same as that of the third doped polysilicon layer 6, and the doping polarity of the fourth doped polysilicon layer 8 can be the same as or opposite to that of the second doped polysilicon layer 4 and the first doped polysilicon layer 2.

[0156] Please refer to Figure 10 , when the doping polarities of the fourth doped polysilicon layer 8 and the third doped polysilicon layer 6 are the same as those of the second doped polysilicon layer 4 and the first doped polysilicon layer 2, no opening needs to be provided on the fourth doped polysilicon layer 8 and the third doped polysilicon layer 6, and the first metal electrode 11 can be in contact with the fourth doped polysilicon layer 8; of course, an opening can also be provided in the fourth doped polysilicon layer 8, and the first metal electrode 11 can pass through the opening 100 to be in contact with the third doped polysilicon layer 6; it can also be that openings are provided in the fourth doped polysilicon layer 8 and the third doped polysilicon layer 6, and the first metal electrode 11 passes through the opening to be in contact with the second doped polysilicon layer 4 or the first doped polysilicon layer 2.

[0157] Please refer to Figure 11 , when the doping polarity of the fourth doped polysilicon layer 8 is opposite to that of the second doped polysilicon layer 4 and the first doped polysilicon layer 2, openings 100 are provided in the fourth doped polysilicon layer 8, the third barrier layer 7, the third doped polysilicon layer 6, and the second barrier layer 3, and the first metal electrode 11 passes through the opening 100 to be in contact with the second doped polysilicon layer 4. Of course, the first metal electrode 11 can also continue to pass through the second doped polysilicon layer 4 and the first barrier layer 3 to be in contact with the first doped polysilicon layer 2.

[0158] As an embodiment of the present invention, the thickness of the third barrier layer 7 is less than or equal to the thickness of the second barrier layer 5.

[0159] In this embodiment, the thickness of the third barrier layer 7 can be less than or equal to the thickness of the second barrier layer 5. In some other embodiments, the thickness of the third barrier layer 7 can also be greater than the thickness of the second barrier layer 5. Among them, the material of the third barrier layer 7 can be the same as or different from the material of the first barrier layer 3.

[0160] In some other embodiments, one or more barrier layers and one or more doped polysilicon layers may be further stacked on the surface of the fourth doped polysilicon layer 8 facing away from the silicon substrate 10 to form a stacked structure in which the barrier layers and the doped polysilicon layers are alternately arranged, so as to further improve the passivation effect of the battery.

[0161] Embodiment 4

[0162] Please refer to Figure 12 , on the basis of any one of Embodiments 1 to 3, the first barrier layer 3 and the second doped polysilicon layer 4 of the passivation contact structure of the solar cell in this embodiment are both in a discontinuous structure, so that the first barrier layer 3 and the second doped polysilicon layer 4 only cover a part of the first doped polysilicon layer 2.

[0163] In this embodiment, both the first barrier layer 3 and the second doped polysilicon layer 4 are non - continuous and full - surface structures.

[0164] The first barrier layer 3 and the second doped polysilicon layer 4 are arranged discontinuously on the first doped polysilicon, so that the first barrier layer 3 and the second doped polysilicon layer 4 are passivated locally. Among them, both the first barrier layer 3 and the second doped polysilicon layer 4 are arranged in a square shape on the first doped polysilicon layer 2. Among them, grooves 9 are formed between adjacent first barrier layers 3 and between adjacent second doped polysilicon layers 4. The first metal electrode 11 is in contact with the first doped polysilicon layer 2 in the groove 9 area, and the first metal electrode 11 is in contact with the second doped polysilicon layer 4 in the second doped polysilicon layer 4 area.

[0165] The passivation contact structure of the solar cell in this embodiment can be applied to a bifacial solar cell or a back - contact solar cell.

[0166] In this embodiment, the use of the first barrier layer 3 and the second doped polysilicon layer 4 can further enhance the passivation effect, and can reduce the area of the first barrier layer 3 and the second doped polysilicon layer 4, reduce the light absorption of the doped polysilicon layer, thereby reducing parasitic absorption and improving the battery efficiency; on the other hand, during the metallization process of the solar cell, since the adjacent first barrier layers 3 and the adjacent second doped polysilicon layers 4 can form a barrier to the paste of the first metal electrode 11, the paste deposition at the position corresponding to the first metal electrode 11 where there is no second doped polysilicon layer 4 can be thicker, that is, the paste deposition in the groove 9 area is thicker. Therefore, the thickness of the first metal electrode 11 in the area corresponding to the non - second doped polysilicon layer 4 is greater than the thickness of the first metal electrode 11 in the area corresponding to the second doped polysilicon layer 4, increasing the welding pull force of the metal electrode and improving the conductivity and battery stability.

[0167] Embodiment 5

[0168] Please refer to Figure 13, this embodiment provides a solar cell, including a silicon substrate 10. The silicon substrate 10 includes a light-facing surface 101 and a backlight surface 102 that is disposed opposite to the light-facing surface 101. The light-facing surface and / or the backlight surface is provided with the solar cell passivation contact structure of any one of the above-mentioned Embodiments 1 to 4, which can improve the passivation effect of the solar cell, thereby improving the cell efficiency.

[0169] In this embodiment, the solar cell is a bifacial solar cell. The light-facing surface 101 and the backlight surface 102 of the silicon substrate 10 can both be provided with the above-mentioned solar cell passivation contact structure, or only the light-facing surface 101 or the backlight surface 102 of the silicon substrate 10 can be provided with the above-mentioned solar cell passivation contact structure.

[0170] In this embodiment, the light-facing surface 101 and / or the backlight surface 102 of the solar cell is provided with the solar cell passivation contact structure of any one of the above-mentioned Embodiments 1 to 4, which can make the back surface of the solar cell have a better passivation effect and improve the cell efficiency.

[0171] For the convenience of description, Figure 13 only the light-facing surface 101 and the backlight surface 102 of the solar cell are schematically shown to be both provided with the solar cell passivation contact structure of the above-mentioned Embodiment 1. Among them, a plurality of solar cell passivation contact structures are provided on both the light-facing surface 101 and the backlight surface 102 of the solar cell, and the doping polarities of the first doped polysilicon layers 2 of the solar cell passivation contact structures on the light-facing surface 101 are the same, the doping polarities of the first doped polysilicon layers 2 of the solar cell passivation contact structures on the backlight surface 102 are the same, and the doping polarity of the first doped polysilicon layer 2 of the solar cell passivation contact structure on the light-facing surface 101 is opposite to the doping polarity of the first doped polysilicon layer 2 of the solar cell passivation contact structure on the backlight surface 102.

[0172] In this embodiment, both the light-facing surface 101 and the backlight surface 102 of the solar cell utilize the above-mentioned solar cell passivation contact structure, which can make the solar cell have a good passivation effect and improve the cell efficiency.

[0173] In this embodiment, the first metal electrode 11 of the solar cell passivation contact structure on the light-facing surface 101 correspondingly contacts the second doped polysilicon layer 4 or the first doped polysilicon layer 2 of the solar cell passivation contact structure on the light-facing surface 101; the first metal electrode 11 of the solar cell passivation contact structure on the backlight surface 102 correspondingly contacts the second doped polysilicon layer 4 or the first doped polysilicon layer 2 of the solar cell passivation contact structure on the backlight surface 102. Among them, one of the first metal electrode 11 on the light-facing surface 101 and the first metal electrode 11 on the backlight surface 102 is the positive electrode, and the other is the negative electrode.

[0174] In this embodiment, an isolation region may be provided between the first doped polysilicon layers 2 of two adjacent passivated contact structures of the light-facing surface 101 and the backlight surface 102 for isolation, or no isolation region needs to be provided, and the first doped polysilicon layers 2 of two adjacent passivated contact structures of the solar cell may be in contact with each other, which is not limited herein.

[0175] Embodiment Six

[0176] Please refer to Figure 14 , this embodiment provides a solar cell, including a silicon substrate 10. The silicon substrate 10 includes a light-facing surface 101 and a backlight surface 102 opposite to the light-facing surface 101. The light-facing surface 101 is locally provided with the passivated contact structure of the solar cell according to any one of Embodiments 1 to 4 above, which can improve the passivation effect of the solar cell, thereby improving the cell efficiency.

[0177] In this embodiment, the solar cell is a bifacial solar cell. The light-facing surface 101 is locally provided with the passivated contact structure of the solar cell according to any one of Embodiments 1 to 4 above. It can be understood that only some areas on the light-facing surface 101 are provided with the above-mentioned passivated contact structure of the solar cell, and other areas can be set with other passivated contact structures.

[0178] As an embodiment of the present invention, a second passivation layer 14 is provided in the area corresponding to the light-facing surface 101 where the passivated contact structure of the solar cell is not provided, and a fifth doped polysilicon layer 15 is provided on the side of the second passivation layer 14 facing away from the silicon substrate 10. The doping polarity of the fifth doped polysilicon layer 15 is the same as that of the first doped polysilicon layer 2.

[0179] In this embodiment, a second passivation layer 14 is provided in the area corresponding to the light-facing surface 101 where the passivated contact structure of the solar cell is not provided, and a fifth doped polysilicon layer 15 is provided on the back of the second passivation layer 14. The second passivation layer 14 and the fifth doped polysilicon layer 15 are used to form another passivated contact structure to passivate the area where the passivated contact structure of the solar cell is not provided, which can further improve the passivation effect of the cell.

[0180] In this embodiment, the doping polarity of the fifth doped polysilicon layer 15 is the same as that of the first doped polysilicon layer 2. It can be understood that: if the doping polarity of the first doped polysilicon layer 2 of the passivated contact structure of the solar cell is P-type, then the doping polarity of the fifth doped polysilicon layer 15 is P-type; or, if the doping polarity of the first doped polysilicon layer 2 of the passivated contact structure of the solar cell is N-type, then the doping polarity of the fifth doped polysilicon layer 15 is N-type.

[0181] As a preferred embodiment of the present invention, the thickness of the fifth doped polysilicon layer 15 is greater than or equal to the thickness of the first doped polysilicon layer 2 of the passivation contact structure of the solar cell on the light-facing surface 101. In this embodiment, the solar cell further includes:

[0182] A second metal electrode 17 disposed on the light-facing surface 101, and the second front metal electrode 17 is in contact with the fifth doped polysilicon layer 15.

[0183] Wherein, the first metal electrode 11 of the passivation contact structure of the solar cell on the light-facing surface 101 is in contact with the second doped polysilicon layer 4 or the first doped polysilicon layer 2, and the polarities of the first metal electrode 11 and the second metal electrode 17 on the light-facing surface 101 are the same.

[0184] In this embodiment, the backlight surface 102 of the solar cell may also be provided with the passivation contact structure of any one of the first to fourth embodiments above, or other passivation contact structures may be provided.

[0185] As an embodiment of the present invention, the backlight surface 102 is locally provided with the passivation contact structure of any one of the first to fourth embodiments above, and the doping polarities of the first doped polysilicon layers 2 of the passivation contact structures of the solar cells on the backlight surface 102 and the light-facing surface 101 are opposite.

[0186] As an embodiment of the present invention, a third passivation layer 20 is provided in the area corresponding to the region where the passivation contact structure of the solar cell is not provided on the backlight surface 102, and a sixth doped polysilicon layer 21 is provided on the side of the third passivation layer 20 facing away from the silicon substrate 10. The doping polarity of the sixth doped polysilicon layer 21 is the same as the doping polarity of the first doped polysilicon layer 2.

[0187] As a preferred embodiment of the present invention, the thickness of the sixth doped polysilicon layer 21 is greater than or equal to the thickness of the first doped polysilicon layer 2 of the passivation contact structure of the solar cell on the backlight surface 102.

[0188] As an embodiment of the present invention, the solar cell includes:

[0189] A third metal electrode 19 disposed on the backlight surface 102, and the third metal electrode 19 is in contact with the sixth doped polysilicon layer 21.

[0190] In this embodiment, the first metal electrode 11 of the passivation contact structure of the solar cell on the backlight surface 102 is in contact with the second doped polysilicon layer 4 or the first doped polysilicon layer 2; wherein, the polarities of the first metal electrode 11 and the third metal electrode 19 on the backlight surface 102 are the same.

[0191] As an embodiment of the present invention, the first doped polysilicon layer 2 of the passivated contact structure of the solar cell on the light-facing surface 101 and the fifth doped polysilicon layer 15 where the light-facing surface 101 is located may be spaced apart or in contact with each other. The first doped polysilicon layer 2 of the passivated contact structure of the solar cell on the backlight surface 102 and the sixth doped polysilicon layer 21 where the backlight surface 102 is located may be spaced apart or in contact with each other.

[0192] Embodiment VII

[0193] Please refer to Figure 15 , this embodiment provides a solar cell, including a silicon substrate 10. The silicon substrate 10 includes a light-facing surface 101 and a backlight surface 102 opposite to the light-facing surface 101. The backlight surface 102 is provided with the passivated contact structure of the solar cell according to any one of Embodiments 1 to 4, which can improve the passivation effect of the solar cell, thereby improving the cell efficiency.

[0194] As an embodiment of the present invention, the solar cell is a back-contact solar cell. The backlight surface 102 of the back-contact solar cell is provided with a P region and an N region, and both the P region and the N region are provided with the passivated contact structure of the solar cell according to any one of Embodiments 1 to 4; the first doped polysilicon layer 2 of the passivated contact structure of the solar cell in the P region is P-type doped polysilicon, and the doped polysilicon layer 2 of the passivated contact structure of the solar cell in the N region is N-type doped polysilicon.

[0195] In this embodiment, the solar cell is a back-contact solar cell. The backlight surface 102 of the back-contact solar cell is alternately provided with a P region and an N region, and the P region and the N region are respectively provided with the passivated contact structure of the solar cell according to any one of Embodiments 1 to 4. Moreover, the doping polarities of the first doped polysilicon layers 2 of two adjacent passivated contact structures on the backlight surface 102 are opposite, that is, the doping polarities of the first doped polysilicon layers 2 in the P region and the N region are opposite.

[0196] In this embodiment, the backlight surface 102 of the solar cell is provided with the passivated contact structure of the solar cell according to any one of Embodiments 1 to 4, which can make the back surface of the back-contact solar cell have a better passivation effect and improve the efficiency of the back-contact solar cell.

[0197] In this embodiment, an isolation region 22 is provided between the first doped polysilicon layers 2 of two adjacent passivated contact structures. Specifically, the isolation region 22 may be a trench or a gap, so as to keep a gap between the first doped polysilicon layers 2 of two adjacent passivated contact structures and achieve good isolation between the first doped polysilicon layers 2 of two adjacent passivated contact structures.

[0198] Embodiment VIII ]>

[0199] Please refer to Figure 16 , this embodiment provides a solar cell, including a silicon substrate 10, the silicon substrate 10 includes a light-facing surface 101 and a backlight surface 102 disposed opposite to the light-facing surface 101, and the backlight surface 102 is locally provided with the solar cell passivation contact structure of any one of the above-mentioned Embodiment 1 to Embodiment 4.

[0200] In this embodiment, the solar cell is a back-contact solar cell, and the backlight surface 102 of the back-contact solar cell is provided with a P region and an N region, and one of the P region and the N region is provided with the solar cell passivation contact structure of any one of the above-mentioned Embodiment 1 to Embodiment 4. Among them, a plurality of solar cell passivation contact structures are provided on the backlight surface 102 of the silicon substrate 10, and the doping polarities of the first doped polysilicon layers 2 of two adjacent solar cell passivation contact structures are opposite.

[0201] Among them, the backlight surface 102 is locally provided with the solar cell passivation contact structure of any one of the above-mentioned Embodiment 1 to Embodiment 4, which can be understood as that only a part of the backlight surface 102 is provided with the above-mentioned solar cell passivation contact structure, and other regions can be provided with other passivation contact structures. It can be that the P region of the backlight surface 102 is provided with the solar cell passivation contact structure of any one of the above-mentioned Embodiment 1 to Embodiment 4, or the N region is provided with the solar cell passivation contact structure of any one of the above-mentioned Embodiment 1 to Embodiment 4.

[0202] In this embodiment, the backlight surface 102 of the solar cell utilizes the solar cell passivation contact structure, which can make the back surface of the solar cell have a good passivation effect and improve the battery efficiency.

[0203] As an embodiment of the present invention, a third passivation layer 20 is provided in the region of the backlight surface 102 corresponding to the region where the solar cell passivation contact structure is not provided, and a sixth doped polysilicon layer 21 is provided on the side of the third passivation layer 20 facing away from the silicon substrate 10, and the doping polarity of the sixth doped polysilicon layer 21 is opposite to the doping polarity of the first doped polysilicon layer 2.

[0204] As a preferred embodiment of the present invention, the thickness of the sixth doped polysilicon layer 21 is greater than or equal to the thickness of the first doped polysilicon layer 2 of the solar cell passivation contact structure on the backlight surface 102.

[0205] As an embodiment of the present invention, the solar cell further includes:

[0206] A fourth metal electrode 28 provided on the backlight surface 102, and the fourth metal electrode 28 is in contact with the sixth doped polysilicon layer 21.

[0207] In this embodiment, the first metal electrode 11 of the passivated contact structure of the solar cell on the backlight surface 102 is in contact with the second doped polysilicon layer 4 or the first doped polysilicon layer 2. Among them, the polarity of the first metal electrode 11 on the backlight surface 102 is opposite to that of the fourth metal electrode 28 on the backlight surface 102.

[0208] As an embodiment of the present invention, an isolation region 22 is provided between the sixth doped polysilicon layer 21 and the first doped polysilicon layer 2. Among them, the isolation region 22 can specifically be a trench or a gap. The isolation region 22 is used to isolate the sixth doped polysilicon layer 21 from the first doped polysilicon layer 2, avoiding contact between the sixth doped polysilicon layer 21 and the first doped polysilicon layer 2, and achieving good isolation between the sixth doped polysilicon layer 21 and the first doped polysilicon layer 2.

[0209] Embodiment Nine

[0210] Please refer to Figures 17-19 , this embodiment provides a solar cell, including a silicon substrate 10, the silicon substrate 10 includes a light-facing surface 101 and a backlight surface 102 opposite to the light-facing surface 101, and the solar cell passivated contact structure of the above Embodiment Four is provided on the light-facing surface 101 and / or the backlight surface 102.

[0211] In this embodiment, the solar cell can be a bifacial solar cell or a back-contact solar cell. Among them, for the convenience of description, Figures 17-19 only the light-facing surface 101 of the solar cell is schematically shown to be provided with the solar cell passivated contact structure of the above Embodiment Four. Of course, the backlight surface 102 of the solar cell can also be provided with the solar cell passivated contact structure of the above Embodiment Four.

[0212] In this embodiment, since both the first barrier layer 3 and the second doped polysilicon layer 4 of the solar cell passivated contact structure are non-continuous whole-surface structures, the first barrier layer 3 and the second doped polysilicon layer 4 are arranged discontinuously on the first doped polysilicon layer 2. The first metal electrode 11 of the solar cell passivated contact structure is in contact with the second doped polysilicon layer 4 or the first doped polysilicon layer 2.

[0213] In this embodiment, by using the first barrier layer 3 and the second doped polysilicon layer 4, the passivation effect can be further enhanced while the areas of the first barrier layer 3 and the second doped polysilicon layer 4 can be reduced, the absorption of light by the doped polysilicon layer can be reduced, thereby reducing parasitic absorption and improving the cell efficiency. On the other hand, during the metallization process of the solar cell, since the paste of the first metal electrode 11 can be blocked between adjacent first barrier layers 3 and between adjacent second doped polysilicon layers 4, the thickness of the first metal electrode 11 corresponding to the region D that is not the second doped polysilicon layer 4 is greater than the thickness of the first metal electrode 11 corresponding to the region C of the second doped polysilicon layer 4. That is, at the position where the first metal electrode 11 corresponds to the region that is not the second doped polysilicon layer 4, the paste of the first metal electrode 11 is deposited thicker, which is beneficial to increasing the welding tensile force of the first metal electrode 11 and improving the conductivity of the first metal electrode 11 and the stability of the solar cell.

[0214] The present invention provides a passivated contact structure for a solar cell, which includes a first passivation layer, a first doped polysilicon layer, a first barrier layer, and a second doped polysilicon layer that are sequentially stacked on the surface of a silicon substrate. By adding a first barrier layer and a second doped polysilicon layer on the surface of the first doped polysilicon layer, and using the combined blocking effect of the first passivation layer and the first barrier layer, excessive impurities can be prevented from diffusing into the interior of the silicon substrate, and the inward diffusion of impurities into the silicon substrate can be reduced, which can significantly improve the passivation effect of the solar cell, thereby improving the cell efficiency. The first barrier layer and the second doped polysilicon layer can also cooperate to achieve a certain passivation effect. And a first barrier layer that is thinner than the first passivation layer is provided between the second doped polysilicon layer and the first doped polysilicon layer. The first barrier layer can allow the formation of the second doped polysilicon layer and the first doped polysilicon layer while playing a certain mutual blocking role, forming a doping concentration difference between the two doped polysilicon layers, which can further improve the passivation effect of the passivated contact structure of the solar cell and improve the efficiency of the solar cell.

[0215] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A back-contact solar cell, characterized in that, It includes a silicon substrate, the silicon substrate includes a light-facing surface and a backlight surface disposed opposite to the light-facing surface, the backlight surface is provided with a P region and an N region, the P region is provided with a passivated contact structure for a solar cell, and the passivated contact structure for a solar cell includes a first passivation layer, a first doped polysilicon layer, a first barrier layer, and a second doped polysilicon layer that are sequentially stacked on the surface of the silicon substrate. The doping polarity of the first doped polysilicon layer is the same as that of the second doped polysilicon layer; wherein, the thickness of the first passivation layer is greater than the thickness of the first barrier layer, and the ratio of the thickness of the first passivation layer to the thickness of the first barrier layer is 1 to 10 and not equal to 1; the thickness of the first passivation layer is 0.5 to 5 nanometers, and the thickness of the first barrier layer is 0.2 to 4.5 nanometers; A third passivation layer and a sixth doped polysilicon layer disposed on a side of the third passivation layer away from the silicon substrate are provided in a region of the backlight surface corresponding to the region where the passivated contact structure for a solar cell is not provided. An isolation region is provided between the sixth doped polysilicon layer and the first doped polysilicon layer. The doping polarity of the sixth doped polysilicon layer is opposite to that of the first doped polysilicon layer, and the thickness of the sixth doped polysilicon layer is greater than the thickness of the first doped polysilicon layer.

2. The back-contact solar cell according to claim 1, wherein The ratio of the thickness of the first passivation layer to the thickness of the first barrier layer is 1 to 4 and not equal to 1.

3. The back-contact solar cell according to claim 1, wherein The ratio of the thickness of the first passivation layer to the thickness of the first barrier layer is 1 to 2 and not equal to 1.

4. The back contact solar cell according to claim 1, characterized in that, The first passivation layer is provided with holes, and the first doped polysilicon layer contacts the silicon substrate through the holes in the first passivation layer.

5. The back contact solar cell according to claim 1, wherein Both the first passivation layer and the first barrier layer are provided with holes, and the hole density of the first passivation layer is less than the hole density of the first barrier layer.

6. The back-contact solar cell according to claim 1, characterized in that, Both the first passivation layer and the first barrier layer are provided with holes, and the average hole diameter of the first passivation layer is less than the average hole diameter of the first barrier layer.

7. The back-contact solar cell according to claim 1, wherein The first passivation layer includes one or a combination of silicon oxide containing boron or gallium, silicon oxynitride containing boron or gallium, and silicon nitride containing boron or gallium.

8. The back-contact solar cell according to claim 1, characterized in that, The first barrier layer includes one or a combination of silicon oxide containing boron or gallium, silicon oxynitride containing boron or gallium, silicon nitride containing boron or gallium, oxygen-rich silicon containing boron or gallium, and nitrogen-rich silicon containing boron or gallium.

9. The back contact solar cell according to claim 8, characterized in that, The oxygen content of the oxygen-rich silicon is 1×10 19 atoms / cm 3 or more.

10. The back-contact solar cell according to claim 8, wherein, The nitrogen content of the nitrogen-rich silicon is 1×10 19 atoms / cm 3 or more.

11. The back-contact solar cell according to claim 1, characterized in that, The first passivation layer, the first doped polysilicon layer, the first barrier layer, and the second doped polysilicon layer are all doped with group IIIA elements; the doping concentration of the second doped polysilicon layer is greater than or equal to the doping concentration of the first doped polysilicon layer.

12. The back contact solar cell according to claim 11, wherein, The doping concentration of the first passivation layer is less than or equal to the doping concentration of the first barrier layer.

13. The back contact solar cell according to claim 1, wherein The thickness of the first doped polysilicon layer is greater than the thickness of the second doped polysilicon layer.

14. The back-contact solar cell according to claim 1, characterized in that, The ratio of the thickness of the first doped polysilicon layer to the thickness of the second doped polysilicon layer is 1 to 50.

15. The back contact solar cell according to claim 13, characterized in that, The ratio of the thickness of the first doped polysilicon layer to the thickness of the second doped polysilicon layer is 2 to 50.

16. The back-contact solar cell according to claim 13, characterized in that, The ratio of the thickness of the first doped polysilicon layer to the thickness of the second doped polysilicon layer is 5 to 50.

17. The back-contact solar cell according to claim 13, characterized in that, The ratio of the thickness of the first doped polysilicon layer to the thickness of the second doped polysilicon layer is 10 to 50.

18. The back-contact solar cell according to claim 13, characterized in that, The thickness of the first doped polysilicon layer is 30 to 350 nanometers, and the thickness of the second doped polysilicon layer is 5 to 150 nanometers.

19. The back contact solar cell according to claim 1, characterized in that, Further comprising: A second barrier layer disposed on a side of the second doped polysilicon layer facing away from the silicon substrate.

20. The back contact solar cell according to claim 19, characterized in that, The thickness of the second barrier layer is less than or equal to the thickness of the first barrier layer.

21. The back contact solar cell according to claim 19, characterized in that, Further comprising: A third doped polysilicon layer disposed on a side of the second barrier layer facing away from the silicon substrate, and the doping polarity of the third doped polysilicon layer is the same as or opposite to the doping polarity of the second doped polysilicon layer.

22. The back contact solar cell according to claim 21, wherein Further comprising: A third barrier layer disposed on a side of the third doped polysilicon layer facing away from the silicon substrate.

23. The back-contact solar cell according to claim 22, wherein, Further comprising: A fourth doped polysilicon layer disposed on a side of the third barrier layer facing away from the silicon substrate, and the doping polarity of the fourth doped polysilicon layer is the same as or opposite to the doping polarity of the second doped polysilicon layer.

24. The back-contact solar cell according to claim 22, wherein, The thickness of the third barrier layer is less than or equal to the thickness of the second barrier layer.

25. The back-contact solar cell according to claim 1, characterized in that, The first barrier layer and the second doped polysilicon layer are both discontinuously disposed on the first doped polysilicon layer.

26. The back-contact solar cell according to claim 23, characterized in that, The thicknesses of the first doped polysilicon layer, the second doped polysilicon layer, the third doped polysilicon layer, and the fourth doped polysilicon layer decrease in sequence.

27. The back contact solar cell according to claim 1, characterized in that, Further comprising: A first metal electrode disposed on the second doped polysilicon layer, and the first metal electrode is in contact with the second doped polysilicon layer.

28. The back contact solar cell according to claim 27, characterized in that, The first metal electrode passes through the second doped polysilicon layer, the first barrier layer and is in contact with the first doped polysilicon layer.

29. The back contact solar cell according to claim 28, wherein, The width of the first metal electrode in the region of the first doped polysilicon layer is less than the width of the first metal electrode in the region of the second doped polysilicon layer.

30. A battery assembly, characterized in that, Comprising the back contact solar cell according to any one of claims 1 to 29.

31. A photovoltaic system, characterized in that, Comprising the battery assembly according to claim 30.

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