TBC solar cell piece, cell assembly and photovoltaic system
By setting holes on the tunnel passivation layer as carrier transport channels, combined with the tunneling characteristics of the tunneling passivation layer, the problems of sensitivity of the tunnel passivation layer and limited passivation effect are solved, and more efficient Carrier transmission and interface passivation improve the photoelectric conversion efficiency of solar cells.
Patent Information
- Application Number
- CN202411348525.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-25
- Publication Date
- 2025-02-11
AI Technical Summary
The tunnel passivation layer of existing TBC solar cells is sensitive to thickness, making it difficult to achieve thicker thickness, and at the same time, the passivation effect is limited, which limits the photoelectric conversion efficiency of the battery.
N-zone holes and P-zone holes are provided on the tunnel passivation layer. These holes are used as the main conveying channels of carriers. Combined with the tunneling characteristics of the tunneling passivation layer, they balance carrier transmission and reduce the sensitivity to thickness and improve the interface passivation effect.
It effectively improves the carrier transmission efficiency, allows the tunnel passivation layer to be thicker, and obtains better interface passivation effect, thereby improving the photoelectric conversion efficiency of solar cells.
Smart Images
Figure CN119421560A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of solar cells, and in particular to a TBC solar cell sheet, a battery assembly and a photovoltaic system. Background Art
[0002] Back-contact solar cells are one of the crystalline silicon solar cells with the highest photoelectric conversion efficiency on the market. Their characteristics are that the grid lines are all located on the back of the cell, and there is no grid line blocking the front, which can maximize the absorption of sunlight. The grid line design on the back can improve the cell series resistance and fill factor as much as possible without considering the impact of shading. Therefore, a higher photoelectric conversion efficiency can be obtained. However, due to the limitations of metal composites and passivation film layers, a higher photoelectric conversion efficiency cannot be obtained.
[0003] TOPCon solar cells are high-efficiency cells based on a carrier selective collection passivation contact structure. The feature is that a passivation contact structure consisting of a tunneling silicon oxide layer (SiOx) and a heavily doped silicon film layer (poly-Si) is prepared on the back of the cell. The passivation contact structure effectively reduces surface recombination and metal contact recombination, thereby improving the open circuit voltage and energy conversion efficiency of the cell. Although the conversion efficiency of TOPCon cells is already high, due to the parasitic absorption of light by the polysilicon layer, it is impossible to mark the front passivation contact structure in front of the cell. The passivation contact structure can only be made at the gate line position, resulting in limited potential for further efficiency improvements for TOPCon cells.
[0004] TBC (tunneling oxide passivated back contact) solar cells combine back contact solar cells with the passivation contact technology of TOPCon cells, which can further improve the solar energy conversion efficiency. TBC solar cells mainly add an ultra-thin tunneling passivation layer between the back of the silicon substrate and the doping layer. Most of the existing research and application of tunneling passivation layers in TBC solar cells are based on TOPCon cells, which use the tunneling characteristics of the ultra-thin tunneling passivation layer to promote the transmission of carriers. However, this is extremely sensitive to the thickness of the tunneling passivation layer and has extremely high requirements for thickness. The tunneling passivation layer needs to be extremely thin (generally controlled below 1.5nm) to achieve a good transmission effect. Once the threshold is exceeded, the conversion efficiency will drop rapidly. In addition, even if the tunneling passivation layer can be made extremely thin to ensure the transmission of carriers, the small thickness will result in limited passivation effect, which limits the application of TBC solar cells. Summary of the invention
[0005] The purpose of the present invention is to provide a TBC solar cell, a battery assembly and a photovoltaic system in view of the existing technical status.
[0006] The tunneling passivation layer structure of the present invention can cooperate with the tunneling characteristics of the tunneling passivation layer through the newly added hole transport channel, and can balance the carriers, thereby effectively improving the carrier transmission efficiency and reducing the sensitivity and dependence of carrier transmission on the ultra-thin thickness of the tunneling passivation layer. The thickness of the tunneling passivation layer can be made thicker, thereby obtaining a better interface passivation effect, and the production processes of the tunneling passivation layer and the doping layer are matched with each other. Compared with the existing ultra-thin tunneling passivation materials, the structure of the tunneling passivation layer of the present invention is easier to produce.
[0007] In order to achieve the above object, the present invention adopts the following technical scheme:
[0008] First, the present invention provides a TBC solar cell, comprising:
[0009] A silicon substrate having a light-receiving surface and a backlight surface opposite to each other,
[0010] A doping layer is provided on the backlight surface, wherein the doping layer includes N-type doping regions and P-type doping regions that are alternately arranged.
[0011] A tunnel passivation layer is provided between the silicon substrate and the doped layer, the tunnel passivation layer includes an N-region passivation layer corresponding to the inner side of the N-type doped region and a P-region passivation layer corresponding to the inner side of the P-type doped region, the N-region passivation layer is provided with an N-region hole opening toward the doped layer, and the P-region passivation layer is provided with a P-region hole opening toward the doped layer,
[0012] The total number of holes in the P region is greater than the total number of holes in the N region.
[0013] In some embodiments, the density of the P-region holes is greater than the density of the N-region holes.
[0014] In some embodiments, the density of the P-region holes is at least 10 times the density of the N-region holes.
[0015] In some embodiments, the ratio of the density of the N-region holes to the density of the P-region holes is 1:10-10000.
[0016] In some embodiments, the ratio of the density of the N-region holes to the density of the P-region holes is 1:100-1000.
[0017] In some embodiments, the density of the holes in the P region is 1×10 7 cm -2 ~1×10 10 cm -2 .
[0018] In some embodiments, the density of the holes in the N region is 1×106 cm -2 ~1×10 9 cm -2 .
[0019] In some embodiments, the density of the holes in the P region decreases from the middle of the backlight surface toward the edges.
[0020] In some embodiments, the density of the N-region holes decreases from the middle of the backlight surface toward the edges.
[0021] In some embodiments, an average opening diameter of the N-region holes is greater than an average opening diameter of the P-region holes.
[0022] In some embodiments, a cross-sectional area of the P-region hole and / or the N-region hole decreases from an opening toward the backlight surface.
[0023] Secondly, the present invention provides a battery assembly, including the above-mentioned TBC solar cell sheet.
[0024] Furthermore, the present invention also provides a photovoltaic system, comprising the above-mentioned battery assembly.
[0025] The beneficial effects of the present invention are:
[0026] In the present invention, N-region holes and P-region holes are arranged on the tunneling passivation layer, and these holes can serve as the main carrier transport channels, thereby allowing some carriers to directly pass through the tunneling passivation layer through the tunneling characteristics, and some carriers are first captured by the holes, and then transition to the energy level on the other side through the tunneling process or thermal excitation. The newly added hole transport channels cooperate with the tunneling characteristics of the tunneling passivation layer to effectively improve the carrier transmission efficiency, and can reduce the sensitivity and dependence of carrier transmission on the ultra-thin thickness of the tunneling passivation layer. The thickness of the tunneling passivation layer can be made thicker, so as to obtain a better interface passivation effect, and then obtain a tunneling passivation layer with good carrier transmission efficiency and passivation effect, effectively improving the photoelectric conversion efficiency of the battery.
[0027] At the same time, since the movement speed of holes is slower than that of electrons, by controlling the number of P-region holes located in the corresponding area inside the P-type doped area (P-region passivation layer) to be greater than the number of N-region holes located in the corresponding area inside the N-type doped area (N-region passivation layer), the carriers can be balanced, thereby further improving the photoelectric conversion efficiency of the battery.
[0028] In addition, since the P-type doping element in the P-type doping area is mostly boron, and the N-type doping element in the N-type doping area is mostly phosphorus, and in view of the fact that the solid solubility of phosphorus in the silicon oxide material is higher than the solid solubility of boron in the silicon oxide material, and the solid solubility of boron increases with increasing temperature, and at the same time, the increase in temperature is conducive to the formation of P-zone holes in the P-zone passivation layer, therefore, when preparing each doping region of the doping layer separately, controlling the temperature of the P-type doping element to be greater than the temperature of the N-type doping element can not only improve the solid solubility of boron in the silicon oxide material and make boron diffuse better, but also produce a larger number of P-zone holes on the P-zone passivation layer inside the P-type doping region. The tunneling passivation layer and the doping layer are matched with each other in production processes. Compared with the existing ultra-thin tunneling passivation material, the structure of the tunneling passivation layer of the present invention is easier to produce. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 The figure is a schematic structural diagram of a TBC solar cell of the present invention.
[0030] Figure 2 for Figure 1 A partial enlarged view of part A.
[0031] Figure 3 It is a schematic diagram of the local structure of the tunneling passivation layer of the present invention.
[0032] Figure 4 This is a scanning electron microscope image of the N-type hole of the present invention (the length scale in the image is 500 nm). DETAILED DESCRIPTION
[0033] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. In addition, 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.
[0034] Reference to "embodiment" or "implementation" herein means that a particular feature, component, or characteristic described in conjunction with the embodiment or implementation may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.
[0035] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.
[0036] First, see Figures 1 to 3 As shown, the present invention provides a TBC solar cell sheet, comprising:
[0037] A silicon substrate 1, wherein the silicon substrate 1 has a light-receiving surface and a backlight surface opposite to each other,
[0038] The doping layer 2 is disposed on the backlight surface, and the doping layer 2 includes N-type doping regions 21 and P-type doping regions 22 that are alternately arranged.
[0039] A tunnel passivation layer 3 is provided between the silicon substrate 1 and the doped layer 2. The tunnel passivation layer 3 includes an N-region passivation layer 31 corresponding to the inner side of the N-type doped region 21 and a P-region passivation layer 32 corresponding to the inner side of the P-type doped region 22. The N-region passivation layer 31 is provided with an N-region hole 41 opening toward the doped layer 2, and the P-region passivation layer 32 is provided with a P-region hole 42 opening toward the doped layer 2.
[0040] The total number of the P-region holes 42 is greater than the total number of the N-region holes 41 .
[0041] In the present invention, N-region holes 41 and P-region holes 42 are arranged on the tunneling passivation layer 3, and these holes can serve as the main carrier transport channels, thereby allowing some carriers to directly pass through the tunneling passivation layer 3 through the tunneling characteristics, and some carriers are first captured by the holes, and then transition to the energy level on the other side through the tunneling process or thermal excitation. The newly added hole transport channels and the tunneling characteristics of the tunneling passivation layer 3 work together to effectively improve the carrier transmission efficiency, and can reduce the sensitivity and dependence of carrier transmission on the ultra-thin thickness of the tunneling passivation layer 3. The thickness of the tunneling passivation layer 3 can be made thicker, so as to obtain a better interface passivation effect, and then obtain a tunneling passivation layer 3 with good carrier transmission efficiency and passivation effect, effectively improving the photoelectric conversion efficiency of the battery.
[0042] At the same time, since the movement speed of holes is slower than that of electrons, by controlling the number of P-region holes 42 located in the corresponding area inside the P-type doping region 22 (P-region passivation layer 32) to be greater than the number of N-region holes 41 located in the corresponding area inside the N-type doping region 21 (N-region passivation layer 31), the carriers can be balanced, thereby further improving the photoelectric conversion efficiency of the battery.
[0043] In addition, since the P-type doping element of the P-type doping region 22 is mostly boron, and the N-type doping element of the N-type doping region 21 is mostly phosphorus, and in view of the fact that the solid solubility of phosphorus in the silicon oxide material is higher than the solid solubility of boron in the silicon oxide material, and the solid solubility of boron increases with increasing temperature, and at the same time, the increase in temperature is conducive to the formation of P-region holes 42 in the P-region passivation layer 32, therefore, when preparing each doping region of the doping layer 2 separately, the temperature of the P-type doping element is controlled to be greater than the temperature of the N-type doping element, which can not only improve the solid solubility of boron in the silicon oxide material and make boron diffuse better, but also produce a larger number of P-region holes 42 on the P-region passivation layer 32 inside the P-type doping region 22. The tunneling passivation layer 3 and the doping layer 2 are matched with each other in production processes. Compared with the existing ultra-thin tunneling passivation material, the structure of the tunneling passivation layer 3 of the present invention is easier to produce.
[0044] The silicon substrate 1 may be P-type monocrystalline silicon, N-type monocrystalline silicon, P-type polycrystalline silicon or N-type polycrystalline silicon, but is not limited thereto, and is preferably N-type monocrystalline silicon. In terms of thickness, the silicon substrate 1 includes a light-receiving surface and a backlight surface that are arranged opposite to each other, wherein the light-receiving surface generally refers to a side that receives light. It should be noted that in some embodiments, the backlight surface may also absorb light incident through the backlight surface, thereby generating a photocurrent.
[0045] Exemplarily, the tunnel passivation layer 3 may be made of silicon oxide.
[0046] Exemplarily, the doping layer 2 may be made of polysilicon.
[0047] In some embodiments, see Figure 2 and Figure 3 As shown, the density of the P region holes 42 is greater than the density of the N region holes 41 .
[0048] Since the movement speed of holes is slower than that of electrons, by controlling the density of P-region holes 42 located on the corresponding area inside the P-type doping region 22 (P-region passivation layer 32) to be greater than the density of N-region holes 41 located on the corresponding area inside the N-type doping region 21 (N-region passivation layer 31), the number of P-region holes 42 is greater than the number of N-region holes 41, and the holes have more channels, thereby balancing the carriers, thereby further improving the photoelectric conversion efficiency of the battery.
[0049] The density of the holes 42 in the P region is denoted as ρp , the density of holes 41 in the N region is denoted as ρ n , then p >ρ n .
[0050] In some embodiments, the density of the P-region holes 42 is at least 10 times the density of the N-region holes 41 .
[0051] When the ratio of the density of the holes 42 in the P region to the density of the holes 41 in the N region (i.e., ρ p / ρ n ) is too low, it is difficult to maintain a good carrier balance, affecting the photoelectric conversion efficiency of the battery.
[0052] In some embodiments, the ratio of the density of the N-region holes 41 to the density of the P-region holes 42 is 1:10-10000.
[0053] Exemplarily, the ratio of the density of the N-region holes 41 to the density of the P-region holes 42 is 1:10, 1:100, 1:500, 1:1000, 1:1500, 1:2000, 1:2500, 1:3000, 1:3500, 1:4000, 1:4500, 1:5000, 1:5500, 1:6000, 1:6500, 1:7000, 1:7500, 1:8000, 1:8500, 1:9000, 1:9500 or 1:10000, but is not limited thereto.
[0054] When the ratio of the density of the holes 42 in the P region to the density of the holes 41 in the N region (i.e., ρ p / ρ n ) is too high, the difference between the density of the P-region holes 42 and the density of the N-region holes 41 is too large, which may easily cause the density of the P-region holes 42 to be too high, thereby affecting the passivation effect of the P-region passivation layer 32.
[0055] In some embodiments, the ratio between the density of the N-region holes 41 and the density of the P-region holes 42 is 1:100-1000.
[0056] Illustratively, the ratio of the density of the N region holes 41 to the density of the P region holes 42 is 1:100, 1:200, 1:300, 1:400, 1:500, 1:600, 1:700, 1:800, 1:900 or 1:1000, but is not limited thereto.
[0057] Within this range, the ratio of the density of the P region holes 42 to the density of the N region holes 41 (i.e., ρ p / ρ n) is more appropriate, which can ensure that the carriers can maintain a good balance, and at the same time the tunnel passivation layer 3 has a good passivation effect in both the P region passivation layer 32 and the N region passivation layer 31.
[0058] In some embodiments, the density of the P region holes 42 is 1×10 7 cm -2 ~1×10 10 cm -2 .
[0059] For example, the density of the P region holes 42 is 1×10 7 cm -2 , 2.5×10 7 cm -2 , 5×10 7 cm -2 , 8×10 7 cm -2 , 1×10 8 cm -2 , 2.5×10 8 cm -2 , 5×10 8 cm -2 , 8×10 8 cm -2 , 1×10 9 cm -2 , 2.5×10 9 cm -2 , 5×10 9 cm -2 , 8×10 9 cm -2 or 1×10 10 cm -2 , but not limited to this.
[0060] When the density of the P region holes 42 is too low, the total number of the P region holes 42 and the N region holes 41 is too small to form an effective channel, which affects the carrier transmission efficiency. When the density of the P region holes 42 is too high, the passivation effect of the P region passivation layer 32 is affected.
[0061] In some embodiments, the density of the N-region holes 41 is 1×10 6 cm -2 ~1×10 9 cm -2 .
[0062] For example, the density of the N-region holes 41 is 1×10 6 cm -2 , 2.5×10 6 cm -2 , 5×10 6 cm-2 , 8×10 6 cm -2 , 1×10 7 cm -2 , 2.5×10 7 cm -2 , 5×10 7 cm -2 , 8×10 7 cm -2 , 1×10 8 cm -2 , 2.5×10 8 cm -2 , 5×10 8 cm -2 , 8×10 8 cm -2 or 1×10 9 cm -2 , but not limited to this.
[0063] When the density of the N-region holes 41 is too low, it is difficult to form an effective channel, which affects the carrier transmission efficiency. When the density of the N-region holes 41 is too high, the density of the P-region holes 42 needs to be set higher, which easily causes the density of the P-region holes 42 to be too high, affecting the passivation effect of the P-region passivation layer 32.
[0064] It can be understood that in one embodiment, the density of the P-region holes 42 is consistent between each P-region passivation layer 32 on the backlight surface, that is, the density of the P-region holes 42 located at the edges of the backlight surface is consistent with the density of the P-region holes 42 located in the middle of the backlight surface. The density of the N-region holes 41 is consistent between each N-region passivation layer 31 on the backlight surface, that is, the density of the N-region holes 41 located at the edges of the backlight surface is consistent with the density of the N-region holes 41 located in the middle of the backlight surface.
[0065] In another embodiment, preferably, the density of the P-region holes 42 decreases from the middle of the backlight surface toward the peripheral edges.
[0066] In the subsequent preparation process, steps such as laser grooving, thermal processing, cell cutting, and lamination are involved. These steps can easily cause stress damage to the tunnel passivation layer 3, and the closer the area is to the edge of the backlight surface, the greater the stress damage it suffers. These stress damages will hinder the transport of carriers and reduce the carrier transport efficiency. Therefore, in the present invention, the density of the P-region holes 42 is set to decrease from the middle of the backlight surface to the surrounding edges, so that the edge P-region passivation layer 32 has more transmission channels, ensuring the overall carrier transmission efficiency and improving the battery conversion efficiency.
[0067] In another embodiment, preferably, the density of the N-region holes 41 decreases from the middle of the backlight surface toward the edges.
[0068] In the subsequent preparation process, steps such as laser grooving, thermal processing, cell cutting, and lamination are involved. These steps can easily cause stress damage to the tunnel passivation layer 3, and the closer the area is to the edge of the backlight surface, the greater the stress damage it suffers. These stress damages will hinder the transport of carriers and reduce the carrier transport efficiency. Therefore, in the present invention, the density of the N-region holes 41 is set to decrease from the middle of the backlight surface to the surrounding edges, so that the edge N-region passivation layer 31 has more transmission channels, ensuring the overall carrier transmission efficiency and improving the battery conversion efficiency.
[0069] In some embodiments, the average opening diameter of the N-region holes 41 is greater than the average opening diameter of the P-region holes 42 .
[0070] Since the density of the N region holes 41 is smaller than that of the P region holes 42 , the average opening diameter of the N region holes 41 can be set relatively large to make it easier for carriers to be transmitted through the N region holes 41 in the N region passivation layer 31 .
[0071] It can be understood that the average opening aperture here can be obtained by evenly selecting N test points on the backlight surface, counting the maximum width of each hole in the N test points as the opening aperture of each hole, and then taking the average value.
[0072] In some embodiments, see Figure 2 and Figure 4 As shown, the cross-sectional area of the P region hole 42 and / or the N region hole 41 decreases from the opening toward the backlight surface. It can be understood that the cross-sectional area here refers to the cross-sectional area of the hole along the direction parallel to the surface where the tunnel passivation layer 3 is located.
[0073] Exemplarily, the P region hole 42 and the N region hole 41 may be regular inverted cone structures, such as pyramid structures, or irregular inverted cone structures.
[0074] In some embodiments, the doping layer 2 is further provided with an isolation region, and the isolation region is provided between the N-type doping region 21 and the P-type doping region 22 .
[0075] In some embodiments, a passivation layer 5 is further provided outside the doping layer 2, and the passivation layer 5 includes at least one of an intrinsic amorphous silicon layer, an intrinsic polycrystalline silicon layer, an intrinsic nanocrystalline silicon layer, an intrinsic mixed crystal silicon layer, a silicon oxide layer, an aluminum oxide layer, a silicon oxynitride layer, a silicon nitride layer, and a carbon nitride silicon oxide layer.
[0076] Secondly, the present invention provides a battery assembly, including the above-mentioned TBC solar cell sheet.
[0077] Furthermore, the present invention also provides a photovoltaic system, comprising the above-mentioned battery assembly.
[0078] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:
[0079] Example 1
[0080] First, this embodiment discloses a TBC solar cell, including:
[0081] A silicon substrate having a light-receiving surface and a backlight surface opposite to each other,
[0082] A doping layer is provided on the backlight surface, wherein the doping layer includes N-type doping regions and P-type doping regions that are alternately arranged.
[0083] A tunnel passivation layer is provided between the silicon substrate and the doped layer, the tunnel passivation layer includes an N-region passivation layer corresponding to the inner side of the N-type doped region and a P-region passivation layer corresponding to the inner side of the P-type doped region, the N-region passivation layer is provided with an N-region hole opening toward the doped layer, and the P-region passivation layer is provided with a P-region hole opening toward the doped layer,
[0084] The total number of holes in the P region is greater than the total number of holes in the N region.
[0085] In this embodiment, the density of the holes in the P region is greater than the density of the holes in the N region.
[0086] In this embodiment, the ratio between the density of the holes in the N region and the density of the holes in the P region is 1:100-1000.
[0087] In this embodiment, the density of the holes in the P region increases from 1×10 9 cm -2 Decrease to 1×10 8 cm -2 .
[0088] In this embodiment, the density of the holes in the N region increases from 1×10 7 cm -2 Decrease to 1×10 6 cm -2 .
[0089] In this embodiment, the cross-sectional areas of the P-region holes and / or the N-region holes decrease gradually from the openings toward the backlight surface.
[0090] Secondly, this embodiment discloses a battery assembly, including the above-mentioned TBC solar cell.
[0091] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.
[0092] Example 2
[0093] First, this embodiment discloses a TBC solar cell, including:
[0094] A silicon substrate having a light-receiving surface and a backlight surface opposite to each other,
[0095] A doping layer is provided on the backlight surface, wherein the doping layer includes N-type doping regions and P-type doping regions that are alternately arranged.
[0096] A tunnel passivation layer is provided between the silicon substrate and the doped layer, the tunnel passivation layer includes an N-region passivation layer corresponding to the inner side of the N-type doped region and a P-region passivation layer corresponding to the inner side of the P-type doped region, the N-region passivation layer is provided with an N-region hole opening toward the doped layer, and the P-region passivation layer is provided with a P-region hole opening toward the doped layer,
[0097] The total number of holes in the P region is greater than the total number of holes in the N region.
[0098] In this embodiment, the density of the holes in the P region is greater than the density of the holes in the N region.
[0099] In this embodiment, the ratio between the density of the holes in the N region and the density of the holes in the P region is 1:100-10000.
[0100] In this embodiment, the density of the holes in the P region increases from 1×10 10 cm -2 Decrease to 1×10 9 cm -2 .
[0101] In this embodiment, the density of the holes in the N region increases from 1×10 7 cm -2 Decrease to 1×10 6 cm -2 .
[0102] In this embodiment, the cross-sectional areas of the P-region holes and / or the N-region holes decrease gradually from the openings toward the backlight surface.
[0103] Secondly, this embodiment discloses a battery assembly, including the above-mentioned TBC solar cell.
[0104] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.
[0105] Example 3
[0106] First, this embodiment discloses a TBC solar cell, including:
[0107] A silicon substrate having a light-receiving surface and a backlight surface opposite to each other,
[0108] A doping layer is provided on the backlight surface, wherein the doping layer includes N-type doping regions and P-type doping regions that are alternately arranged.
[0109] A tunnel passivation layer is provided between the silicon substrate and the doped layer, the tunnel passivation layer includes an N-region passivation layer corresponding to the inner side of the N-type doped region and a P-region passivation layer corresponding to the inner side of the P-type doped region, the N-region passivation layer is provided with an N-region hole opening toward the doped layer, and the P-region passivation layer is provided with a P-region hole opening toward the doped layer,
[0110] The total number of holes in the P region is greater than the total number of holes in the N region.
[0111] In this embodiment, the density of the holes in the P region is greater than the density of the holes in the N region.
[0112] In this embodiment, the ratio between the density of the holes in the N region and the density of the holes in the P region is 1:10-100.
[0113] In this embodiment, the density of the holes in the P region increases from 1×10 8 cm -2 Decrease to 5×10 7 cm -2 .
[0114] In this embodiment, the density of the holes in the N region increases from 5×10 6 cm -2 Decrease to 1×10 6 cm -2 .
[0115] In this embodiment, the cross-sectional areas of the P-region holes and / or the N-region holes decrease gradually from the openings toward the backlight surface.
[0116] Secondly, this embodiment discloses a battery assembly, including the above-mentioned TBC solar cell.
[0117] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.
[0118] Example 4
[0119] First, this embodiment discloses a TBC solar cell, including:
[0120] A silicon substrate having a light-receiving surface and a backlight surface opposite to each other,
[0121] A doping layer is provided on the backlight surface, wherein the doping layer includes N-type doping regions and P-type doping regions that are alternately arranged.
[0122] A tunnel passivation layer is provided between the silicon substrate and the doped layer, the tunnel passivation layer includes an N-region passivation layer corresponding to the inner side of the N-type doped region and a P-region passivation layer corresponding to the inner side of the P-type doped region, the N-region passivation layer is provided with an N-region hole opening toward the doped layer, and the P-region passivation layer is provided with a P-region hole opening toward the doped layer,
[0123] The total number of holes in the P region is greater than the total number of holes in the N region.
[0124] In this embodiment, the density of the holes in the P region is greater than the density of the holes in the N region.
[0125] In this embodiment, the ratio between the density of the holes in the N region and the density of the holes in the P region is 1:10-500.
[0126] In this embodiment, the density of the holes in the P region increases from 1×10 10 cm -2 Decrease to 5×10 9 cm -2 .
[0127] In this embodiment, the density of the holes in the N region increases from 5×10 8 cm -2 Decrease to 2×10 7 cm -2 .
[0128] In this embodiment, the cross-sectional areas of the P-region holes and / or the N-region holes decrease gradually from the openings toward the backlight surface.
[0129] Secondly, this embodiment discloses a battery assembly, including the above-mentioned TBC solar cell.
[0130] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.
[0131] Example 5
[0132] First, this embodiment discloses a TBC solar cell, including:
[0133] A silicon substrate having a light-receiving surface and a backlight surface opposite to each other,
[0134] A doping layer is provided on the backlight surface, wherein the doping layer includes N-type doping regions and P-type doping regions that are alternately arranged.
[0135] A tunnel passivation layer is provided between the silicon substrate and the doped layer, the tunnel passivation layer includes an N-region passivation layer corresponding to the inner side of the N-type doped region and a P-region passivation layer corresponding to the inner side of the P-type doped region, the N-region passivation layer is provided with an N-region hole opening toward the doped layer, and the P-region passivation layer is provided with a P-region hole opening toward the doped layer,
[0136] The total number of holes in the P region is greater than the total number of holes in the N region.
[0137] In this embodiment, the density of the holes in the P region is greater than the density of the holes in the N region.
[0138] In this embodiment, the ratio between the density of the holes in the N region and the density of the holes in the P region is 1:10-1000.
[0139] In this embodiment, the density of the holes in the P region increases from 1×10 10 cm -2 Decrease to 1×10 9 cm -2 .
[0140] In this embodiment, the density of the holes in the N region increases from 1×10 8 cm -2 Decrease to 1×10 7 cm -2 .
[0141] In this embodiment, the cross-sectional areas of the P-region holes and / or the N-region holes decrease gradually from the openings toward the backlight surface.
[0142] Secondly, this embodiment discloses a battery assembly, including the above-mentioned TBC solar cell.
[0143] Furthermore, this embodiment discloses a photovoltaic system, including the above-mentioned battery assembly.
[0144] The solar cells prepared in Examples 1 to 5 were subjected to performance tests, and the test results are as follows:
[0145]
[0146] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the field can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.
Claims
1. A TBC solar cell, characterized in that: include: A silicon substrate having a light-receiving surface and a backlight surface opposite to each other, A doping layer is provided on the backlight surface, wherein the doping layer includes N-type doping regions and P-type doping regions that are alternately arranged. A tunnel passivation layer is provided between the silicon substrate and the doped layer, the tunnel passivation layer includes an N-region passivation layer corresponding to the inner side of the N-type doped region and a P-region passivation layer corresponding to the inner side of the P-type doped region, the N-region passivation layer is provided with an N-region hole opening toward the doped layer, and the P-region passivation layer is provided with a P-region hole opening toward the doped layer, The total number of holes in the P region is greater than the total number of holes in the N region.
2. A TBC solar cell according to claim 1, characterized in that: The density of the holes in the P region is greater than the density of the holes in the N region.
3. A TBC solar cell according to claim 2, characterized in that: The density of the holes in the P region is at least 10 times that of the holes in the N region.
4. A TBC solar cell according to claim 3, characterized in that: The ratio between the density of the holes in the N region and the density of the holes in the P region is 1:10 to 10000.
5. A TBC solar cell according to claim 4, characterized in that: The ratio between the density of the holes in the N region and the density of the holes in the P region is 1:100-1000.
6. A TBC solar cell according to claim 1, characterized in that: The density of the holes in the P region is 1×10 7 cm -2 ~1×10 10 cm -2 .
7. A TBC solar cell according to claim 1, characterized in that: The density of the holes in the N region is 1×10 6 cm -2 ~1×10 9 cm -2 .
8. A TBC solar cell according to claim 1, characterized in that: The density of the holes in the P region decreases gradually from the middle of the backlight surface to the edges thereof.
9. A TBC solar cell according to claim 1, characterized in that: The density of the holes in the N region decreases gradually from the middle of the backlight surface to the edges thereof.
10. A TBC solar cell according to claim 1, characterized in that: The average opening diameter of the holes in the N region is greater than the average opening diameter of the holes in the P region.
11. A TBC solar cell according to claim 1, characterized in that: The cross-sectional area of the P-region hole and / or the N-region hole decreases from the opening toward the backlight surface.
12. A battery assembly, characterized in that: It comprises a TBC solar cell according to any one of claims 1 to 11.
13. A photovoltaic system, characterized in that: Comprising the battery assembly according to claim 12.
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