Back contact battery and photovoltaic module
By designing alternating doped regions and groove structures on the substrate surface of the TBC battery, combined with the use of intrinsic isolation regions, the problem of poor passivation effect on the back of the TBC battery is solved, and higher efficiency and passivation effect are achieved.
Patent Information
- Application Number
- CN202421902954.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-07
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2034-08-07
AI Technical Summary
The back passivation effect of existing TBC batteries is poor and has low efficiency.
A back contact battery is designed, and the first side surface of the substrate is provided with alternate first doped regions and second doped regions, with different types of doped elements, and grooves are provided in the doped regions to form uneven surfaces to improve light reflectivity, and at the same time, the doped regions are isolated through the intrinsic isolation region to reduce the penetration of doped elements.
The reflectivity and light utilization of the back contact battery are improved, the efficiency of the battery is enhanced, and the passivation effect is improved through effective diffusion control of doped elements.
Smart Images
Figure CN222941162U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of photovoltaics, and particularly to a back contact battery and a photovoltaic module. Background Art
[0002] IBC (Interdigitated Back Contact) cells emerged in the 1970s. Local phosphorus and boron diffusions are respectively carried out on the back of the cell to form finger-shaped cross-arranged P regions and N regions; the positive and negative electrodes of the IBC cell are both on the back of the cell, and there is no metal shading on the front, which greatly improves the optical absorption of the cell. Based on the existing IBC cell structure, the TBC cell introduces the TOPCon cell structure, which can significantly reduce the carrier recombination loss in the silicon substrate and the emitter, especially in the metal contact area. At present, a large number of technologies for improving the passivation performance of TBC cells have been developed. However, the existing TBC cells still have problems of poor back passivation effect and poor efficiency. Summary of the Utility Model
[0003] Based on this, it is necessary to provide a back contact battery and a photovoltaic module with better passivation effect and higher efficiency.
[0004] The first aspect of this application provides a back contact battery, including:
[0005] A substrate; and
[0006] A first functional film layer disposed on the first side of the substrate. The first functional film layer includes first doping regions and second doping regions that are alternately arranged along a preset direction and are insulated from each other. The types of doping elements in the first doping regions and the second doping regions are different;
[0007] Wherein, on the surface of the first side of the substrate, a first groove and a second groove are respectively provided at positions corresponding to the first doping regions and the second doping regions. The depth of the first groove is greater than the depth of the second groove, so that the thickness dimension of the first doping regions is greater than the thickness dimension of the second doping regions.
[0008] In one embodiment, an intrinsic isolation region is provided between each adjacent first doping region and second doping region.
[0009] In one embodiment, the surface of the first functional film layer facing away from the substrate forms a plane.
[0010] In one embodiment, the back contact battery further includes a tunneling oxide layer. The tunneling oxide layer is located between the substrate and the first functional film layer, and part of the structure is located in the first groove and the second groove.
[0011] In one embodiment, the thickness of the first functional film layer is 300 - 500 nanometers, the difference in thickness dimensions between the first doped region and the second doped region is 100 nanometers; the thickness of the tunneling oxide layer is 0.1 - 10 nanometers, the depth of the first groove is 150 - 250 nanometers, and the depth of the second groove is 100 - 200 nanometers.
[0012] In one embodiment, the width of the intrinsic isolation region along the preset direction is 50 - 100 micrometers, and the widths of the first doped region and the second doped region along the preset direction are both 100 - 200 micrometers.
[0013] In one embodiment, the bottom walls of the first groove and the second groove are perpendicular to the thickness direction of the substrate.
[0014] In one embodiment, the first groove and the second groove are configured as strip-shaped grooves. In the projection of the first functional film layer on the substrate, the outer contour of the projection of the first doped region coincides with the outer contour of the first groove, and the outer contour of the projection of the second doped region coincides with the outer contour of the second groove.
[0015] In one embodiment, the first doped region is doped with a P-type element, and the second doped region is doped with an N-type element.
[0016] The second aspect of the present application provides a photovoltaic module. In one embodiment, it includes at least one battery string, and the battery string includes at least two of the above-mentioned back-contact batteries.
[0017] Beneficial effects of the above-mentioned back-contact battery and photovoltaic module:
[0018] Since on the surface of the first side of the substrate, a first groove and a second groove are respectively provided at positions corresponding to the first doped region and the second doped region, and the depth of the first groove is greater than the depth of the second groove, on the surface of the first side of the substrate, the bottom wall of the first groove is lower than the bottom wall of the second groove. Therefore, on the surface of the first functional film layer facing the substrate, an uneven surface is constructed, which enables the light emitted from the substrate to be more reflected back into the substrate by this uneven surface, improving the reflectivity of the first side (i.e., the back side) of the back-contact battery, improving the light utilization rate of the back-contact battery, and improving the efficiency of the back-contact battery.
[0019] In addition, the depth of the first groove is greater than that of the second groove, so that the thickness dimension of the first doped region is greater than that of the second doped region. As long as the first doped region is doped first and then the second doped region is diffused during doping, the diffusion of the doping elements in the first doped region and the second doped region can be kept consistent. Specifically, for the case where the first doped region is diffused first and then the second doped region is diffused, during the diffusion of the second doped region, the doping elements in the first doped region are pushed in again. Since the thickness dimension of the first doped region is greater than that of the second doped region, even when the doping of the second doped region ends, although the doping elements in the first doped region are pushed deeper towards the substrate side, the situation where the doping elements penetrate the first doped region can be reduced to a certain extent, thereby improving the passivation effect of the back contact battery. Description of the Drawings
[0020] Figure 1 Schematic structural diagram of the back contact battery provided by the embodiment of the present application;
[0021] Figure 2 Schematic structural diagram of the substrate in the manufacturing method of the back contact battery provided by the embodiment of the present application;
[0022] Figure 3 Schematic diagram of forming the first groove and the second groove on the substrate in the manufacturing method of the back contact battery provided by the embodiment of the present application;
[0023] Figure 4 Schematic diagram of forming the intrinsic amorphous silicon material layer on the first side and the second side of the substrate in the manufacturing method of the back contact battery provided by the embodiment of the present application;
[0024] Figure 5 Schematic diagram of forming the first mask layer in the manufacturing method of the back contact battery provided by the embodiment of the present application;
[0025] Figure 6 Schematic diagram of etching the oxide material layer in the manufacturing method of the back contact battery provided by the embodiment of the present application;
[0026] Figure 7 Schematic diagram of forming the first doped region in the manufacturing method of the back contact battery provided by the embodiment of the present application;
[0027] Figure 8 Schematic diagram of forming the second mask layer in the manufacturing method of the back contact battery provided by the embodiment of the present application;
[0028] Figure 9 Schematic diagram of etching the oxide material layer and the borosilicate glass material layer in the manufacturing method of the back contact battery provided by the embodiment of the present application;
[0029] Figure 10 Schematic diagram of forming a second doped region in the manufacturing method of the back contact battery provided by the embodiment of the present application;
[0030] Figure 11 Schematic diagram of removing the film layer on the surface of the second side of the substrate in the manufacturing method of the back contact battery provided by the embodiment of the present application;
[0031] Figure 12 Schematic diagram of forming a textured structure on the surface of the second side of the substrate in the manufacturing method of the back contact battery provided by the embodiment of the present application.
[0032] Explanation of the reference numerals in the drawings:
[0033] 100, back contact battery;
[0034] 10, substrate; 20, first functional film layer; 30, first doped region; 301, first groove; 40, intrinsic isolation region; 50, second doped region; 501, second groove; 60, tunneling oxide layer; 61, tunneling oxide material layer; 71, first passivation layer; 72, first antireflection layer; 73, second passivation layer; 74, first electrode; 75, second electrode; 81, first mask layer; 82, second mask layer; 83, oxide material layer; 84, intrinsic amorphous silicon material layer; 85, borosilicate glass material layer; 86, phosphosilicate glass material layer; 87, intrinsic polysilicon material layer; 88, textured structure;
[0035] F, first side; S, second side. Detailed implementation manners
[0036] In order to make the above objects, features and advantages of the present utility model more obvious and understandable, the following detailed description of the specific implementation manners of the present utility model will be given with reference to the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present utility model. However, the present utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present utility model. Therefore, the present utility model is not limited by the specific embodiments disclosed below.
[0037] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.
[0038] In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present utility model, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.
[0039] In the present utility model, unless otherwise clearly specified and defined, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.
[0040] In the present utility model, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.
[0041] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation.
[0042] The following will describe the solar cell and its manufacturing method according to the embodiments of the present application with reference to the accompanying drawings. It should be noted that in the present application, the back contact battery is taken as an example of the TBC battery for illustration. The back contact battery can also be set as other types of batteries according to actual needs, such as HBC type solar cells, IBC batteries with traditional structures, etc. The situation where the back contact battery is of other types is similar and will not be elaborated here.
[0043] Figure 1 It is a schematic structural diagram of the back contact battery provided by the embodiment of the present application.
[0044] Refer to Figure 1 , the embodiment of the present application provides a back contact battery 100, including: a substrate 10 and a first functional film layer 20.
[0045] The first functional film layer 20 is disposed on the first side F of the substrate 10. The first functional film layer 20 includes a first doping region 30 and a second doping region 50 that are alternately arranged and insulated from each other along a preset direction, and the types of doping elements in the first doping region 30 and the second doping region 50 are different.
[0046] Among them, on the surface of the first side F of the substrate 10, a first groove 301 and a second groove 501 are respectively provided corresponding to the positions of the first doping region 30 and the second doping region 50. The depth of the first groove 301 is greater than the depth of the second groove 501, so that the thickness dimension of the first doping region 30 is greater than the thickness dimension of the second doping region 50.
[0047] It can be understood that the number of the first doping region 30 and the second doping region 50 in the first functional film layer is provided with a plurality of Figure 1 The back contact battery only shows a partial structure in the whole battery, and only the structure of a group of adjacent first doping region 30 and second doping region 50 is illustrated. The structures of the remaining groups of first doping region 30 and second doping region 50 are similar and will not be elaborated here.
[0048] In the embodiment of the present application, in the surface of the first side F of the substrate 10, a first groove 301 and a second groove 501 are respectively provided corresponding to the positions of the first doping region 30 and the second doping region 50. The depth of the first groove 301 is greater than the depth of the second groove 501. In the surface of the first side F of the substrate 10, the bottom wall of the first groove 301 is lower than the bottom wall of the second groove 501. Therefore, on the surface of the first functional film layer 20 facing the substrate 10, an uneven surface is constructed, which enables the light emitted from the substrate 10 to be more reflected back into the substrate 10 by this uneven surface, improving the reflectivity of the first side (i.e., the back side) of the back contact battery 100, enhancing the light utilization rate of the back contact battery, and improving the efficiency of the back contact battery.
[0049] In addition, the depth of the first groove 301 is greater than the depth of the second groove 501, so that the thickness dimension of the first doping region 30 is greater than the thickness dimension of the second doping region 50. As long as the first doping region 30 is doped first and then the second doping region 50 is diffused during doping, the diffusion conditions of the doping elements in the first doping region 30 and the second doping region 50 can be kept consistent. Specifically, for the case where the first doping region 30 is diffused first and then the second doping region 50 is diffused, during the diffusion process of the second doping region 50, the doping elements in the first doping region 30 are pushed forward again. Since the thickness dimension of the first doping region 30 is greater than the thickness dimension of the second doping region 50, even when the doping of the second doping region 50 ends, although the doping elements in the first doping region 30 are pushed deeper towards the substrate 10 side, the situation where the doping elements penetrate the first doping region 30 can be reduced to a certain extent, thereby improving the passivation effect of the back contact battery.
[0050] It can be understood that as long as the depths of the first groove 301 and the second groove 501 are different, the thicknesses of the corresponding first doping region 30 and second doping region 50 will be different. In this way, as long as the doping region with a thicker thickness is doped first, the same technical effect can be achieved.
[0051] In the embodiment of the present application, an intrinsic isolation region 40 is provided between adjacent first doping regions 30 and second doping regions 50. The film material in the intrinsic isolation region can be, for example, intrinsic polysilicon.
[0052] Since the first doping region 30 and the second doping region 50 are isolated by the intrinsic isolation region 40, and the intrinsic isolation region is an undoped region, the first doping region 30 and the second doping region 50 can be well isolated. Compared with the related art where isolation grooves are provided in the first doping region 30 and the second doping region 50 to achieve isolation, the step of grooving is reduced, the cost can be reduced. In addition, the damage to the film layer during the grooving process is avoided, the short-circuit current and open-circuit voltage of the battery are increased, and finally the photoelectric conversion efficiency of the battery is improved.
[0053] In the embodiment of the present application, a plane is formed on the surface of the first functional film layer 20 facing away from the substrate 10.
[0054] With such a setting, on the one hand, the appearance of the outer surface of the back-contact battery 100 is more beautiful. In addition, it can also ensure that the thickness dimension of the first doping region 30 is greater than the thickness dimension of the second doping region 50, and the intrinsic isolation region 40 does not need to be doped, so there is no hidden danger of too deep diffusion depth of doping elements. Therefore, the thickness dimension of the intrinsic isolation region 40 can be set to the minimum.
[0055] Further, the back-contact battery 100 further includes a tunneling oxide layer 60. The tunneling oxide layer 60 is located between the substrate 10 and the first functional film layer 20, and part of the structure is located in the first groove 301 and the second groove 501. For example, the part of the tunneling oxide layer 60 corresponding to the first groove 301 is deposited in the first groove 301, and the part of the tunneling oxide layer 60 corresponding to the second groove 501 is deposited in the second groove 501.
[0056] In the embodiment of the present application, the thickness of the first functional film layer 20 is 300 - 500 nanometers, and the difference in thickness dimensions between the first doping region 30 and the second doping region 50 is 100 nanometers. The thickness of the tunneling oxide layer 60 is 0.1 - 10 nanometers, preferably 1 - 2 nanometers. The depth of the first groove 301 is 150 - 250 nanometers, and the depth of the second groove 501 is 100 - 200 nanometers.
[0057] With such a setting, the whole tunneling oxide layer 60 and part of the structure of the first functional film layer 20 facing the substrate 10 are deposited in the first groove 301 or the second groove 501. Specifically, the thickness dimension of the first doping region 30 can be 350 nanometers, and the thickness dimension of the second doping region 50 can be 250 nanometers.
[0058] Further, the width of the intrinsic isolation region 40 along the preset direction is 50 - 100 micrometers, and the widths of the first doping region 30 and the second doping region 50 along the preset direction are both 100 - 200 micrometers.
[0059] Further, the bottom walls of the first groove 301 and the second groove 501 are perpendicular to the thickness direction of the substrate 10. With such a setting, the position on the first functional film layer 20 corresponding to the bottom wall has a reflective plane, making the reflection effect on the light in the substrate 10 better.
[0060] In the embodiment of the present application, the first groove 301 and the second groove 501 are configured as strip-shaped grooves. In the projection of the first functional film layer 20 on the substrate 10, the outer contour of the projection of the first doping region 30 coincides with the outer contour of the first groove 301, and the outer contour of the projection of the second doping region 50 coincides with the outer contour of the second groove 501.
[0061] With such a setting, it can be ensured that each part of each first doping region 30 and each second doping region 50 has a uniform thickness.
[0062] Further, the first doping region 30 is doped with P-type elements, and the second doping region 50 is doped with N-type elements. Since the first doping region 30 is doped with P-type elements and the second doping region 50 is doped with N-type elements, the reaction temperature during the doping process of the first doping region 30 is higher than that of the second doping region 50. Since the thickness dimension of the first doping region 30 is larger than that of the second doping region 50, it can be avoided that the doping elements in the first doping region 30 push too deep towards the substrate 10 side and penetrate the first doping region 30, damaging the passivation effect.
[0063] Continue to refer to Figure 1 , the back-contact battery 100 further includes a first passivation layer 71 and a first antireflection layer 72, and the first passivation layer 71 and the first antireflection layer 72 are sequentially stacked on the surface of the first functional film layer 20 facing away from the substrate 10.
[0064] Further, the back-contact battery 100 further includes a second passivation layer 73, and the second passivation layer 73 is disposed on the surface of the textured structure 88 on the second side S of the substrate 10. The second passivation layer 73 can be a stack of multiple film layers, and the multiple film layers can include an antireflection layer, so that the second passivation layer 73 plays the roles of passivation and antireflection.
[0065] The solar cell further includes a first electrode 74 and a second electrode 75, and the first electrode 74 and the second electrode 75 are alternately arranged with each other at intervals. The first electrode 74 is disposed at a position on the first antireflection layer 72 corresponding to the first doping region 30 and is in ohmic contact with the first doping region 30, and the second electrode 75 is disposed at a position on the first antireflection layer 72 corresponding to the second doping region 50 and is in ohmic contact with the second doping region 50.
[0066] In a second aspect of the embodiments of the present application, a photovoltaic module is further provided, which includes at least one battery string, and the battery string includes at least two back-contact batteries 100 as described in the foregoing embodiments. The back-contact batteries 100 can be connected together by string soldering.
[0067] In a fourth aspect of the embodiments of the present application, a photovoltaic system is further provided, which includes the above-mentioned photovoltaic module.
[0068] The photovoltaic system can be applied in a photovoltaic power station, such as a ground power station, a rooftop power station, a water surface power station, etc., and can also be applied to devices or apparatuses that use solar energy for power generation, such as a user solar power supply, a solar street lamp, a solar vehicle, a solar building, and so on. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited thereto, that is to say, the photovoltaic system can be applied in all fields that require solar power generation. Taking a photovoltaic power generation system network as an example, the photovoltaic system can include a photovoltaic array, a busbar box, and an inverter. The photovoltaic array can be an array combination of multiple photovoltaic modules. For example, multiple photovoltaic modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the busbar box, and the busbar box can collect the current generated by the photovoltaic array. After the collected current flows through the inverter and is converted into alternating current required by the commercial power grid, it is connected to the commercial power grid to realize solar power supply.
[0069] The embodiments of the present application also provide a manufacturing method of a back-contact battery for manufacturing the above-mentioned back-contact battery 100.
[0070] Figure 2 It is a schematic structural diagram of a substrate in the manufacturing method of the back-contact battery provided by the embodiments of the present application; Figure 3 It is a schematic diagram of forming a first groove and a second groove on the substrate in the manufacturing method of the back-contact battery provided by the embodiments of the present application; Figure 4 It is a schematic diagram of forming an intrinsic amorphous silicon material layer on the first side and the second side of the substrate in the manufacturing method of the back-contact battery provided by the embodiments of the present application; Figure 5 It is a schematic diagram of forming a first mask layer in the manufacturing method of the back-contact battery provided by the embodiments of the present application; Figure 6 It is a schematic diagram of etching an oxide material layer in the manufacturing method of the back-contact battery provided by the embodiments of the present application; Figure 7 It is a schematic diagram of forming a first doping region in the manufacturing method of the back-contact battery provided by the embodiments of the present application; Figure 8 It is a schematic diagram of forming a second mask layer in the manufacturing method of the back-contact battery provided by the embodiments of the present application; Figure 9 It is a schematic diagram of etching an oxide material layer and a borosilicate glass material layer in the manufacturing method of the back-contact battery provided by the embodiments of the present application; Figure 10 It is a schematic diagram of forming a second doping region in the manufacturing method of the back-contact battery provided by the embodiments of the present application; Figure 11Schematic diagram of removing the film layer on the surface of the second side of the substrate in the manufacturing method of the back-contact battery provided by the embodiment of the present application; Figure 12 Schematic diagram of forming a textured structure on the surface of the second side of the substrate in the manufacturing method of the back-contact battery provided by the embodiment of the present application.
[0071] Referring to Figures 2 - 12 , the method includes the following steps:
[0072] 1) Referring to Figure 2 , polish and clean the substrate 10, and form a polished surface with a tower base size of 10 - 20 μm on the first side F and the second side S of the substrate 10. The first side F and the second side S are opposite surfaces.
[0073] 2) Print a protective layer slurry (the method includes laser, photolithography, and the slurry is not limited) at positions corresponding to the first doping region 30 and the intrinsic isolation region 40 on the surface of the first side F of the substrate 10, where the width of the intrinsic isolation region 40 is 50 - 100 μm.
[0074] 3) Etch the surface of the first side F of the substrate 10 with an alkaline solution to form a second groove 501 with a width of 100 - 200 μm and a depth of 100 - 200 nm. And remove the protective layer slurry in step 2).
[0075] 4) Print a protective layer slurry in the region of the substrate 10 corresponding to the second doping region 50 and the intrinsic isolation region 40.
[0076] 5) Etch the position corresponding to the first doping region 30 on the surface of the first side F of the substrate 10 with an alkaline solution to form a first groove 301 with a width of 100 - 200 μm and a depth of 150 - 250 nm, as Figure 3 shown.
[0077] 6) Referring to Figure 4 , form a stack of a tunneling oxide material layer 61, an intrinsic amorphous silicon material layer 84 (300 - 500 nm), and an oxide material layer 83 (50 - 60 nm) on both the first side F and the second side S of the substrate 10.
[0078] 7) Referring to Figure 5 , deposit a first mask layer 81 that is acid-resistant and alkali-insoluble on the first side F of the substrate 10, that is, on the oxide material layer 83. The first mask layer 81 can be wax, ink, etc., and its covered area is the area on the surface of the first side F of the substrate 10 corresponding to the second doping region 50 and the intrinsic isolation region 40.
[0079] 8) Referring to Figure 6, Use a chain machine to remove the oxide material layer 83 in the area not covered by the first mask layer 81 through HF cleaning, and remove the first mask layer 81. Expose the position in the intrinsic amorphous silicon material layer 84 corresponding to the first doped region 30.
[0080] 9) Refer to Figure 7 , for Figure 6 , perform high-temperature boron diffusion on the exposed area in the intrinsic amorphous silicon material layer 84 to form the first doped region 30, and form a borosilicate glass material layer (BSG) 85 on both the first side F and the second side S. Among them, the intrinsic amorphous silicon material layer 84 on the second side S and the first side F of the substrate 10 is also crystallized into an intrinsic polycrystalline silicon material layer 87. The positions in the intrinsic amorphous silicon material layer 84 corresponding to the intrinsic isolation region 40 and the second doped region 50 are protected by the oxide material layer 83, blocking the diffusion of doped atoms.
[0081] 10) Refer to Figure 8 , deposit a second mask layer 82 on the surface of the borosilicate glass material layer 85. The covered area of the second mask layer 82 is the position on the borosilicate glass material layer 85 corresponding to the first doped region 30 and the intrinsic isolation region 40.
[0082] 11) Refer to Figure 9 , use a chain machine to remove the parts of the oxide material layer 83 and the borosilicate glass material layer 85 on the first side F that are not covered by the second mask layer 82 through HF cleaning. Expose the part in the intrinsic polycrystalline silicon material layer 87 corresponding to the second doped region 50. And remove the second mask layer 82.
[0083] 12) Refer to Figure 10 , for Figure 9 , perform high-temperature phosphorus diffusion on the exposed area in the intrinsic polycrystalline silicon material layer 87 to form the second doped region 50, and form a phosphosilicate glass material layer (PSG) 86 on the first side F. The positions in the intrinsic polycrystalline silicon material layer 87 corresponding to the intrinsic isolation region 40 and the first doped region 30 are protected by the borosilicate glass material layer 85, which can block the diffusion of doped atoms in this area. At this time, the intrinsic polycrystalline silicon material layer 87 between the first doped region 30 and the second doped region 50 forms the intrinsic isolation region 40.
[0084] 13) Refer to Figure 11 , use a chain machine to remove the borosilicate glass material layer 85 and the oxide material layer 83 on the surface of the second side S of the substrate 10 by HF cleaning.
[0085] 14) Refer to Figure 12 , remove the intrinsic polycrystalline silicon material layer 87 on the surface of the second side S of the substrate 10, etch a textured structure 88 on the surface of the second side S of the substrate 10, and remove the phosphosilicate glass material layer 86, the borosilicate glass material layer 85, and the oxide material layer 83 on the first side F.
[0086] 15) Refer to Figure 1 , on the basis of the structure formed in step 14), deposit a first passivation layer 71 and a first antireflection layer 72 on the first side F, and deposit a second passivation layer 73 on the second side S. Form a first electrode 74 and a second electrode 75 at positions corresponding to the first doping region 30 and the second doping region 50 on the first antireflection layer 72 respectively.
[0087] In the above method, the laser grooving method is not adopted throughout the process, reducing the damage to the film layer, improving the passivation performance of the back contact battery, and improving the battery efficiency. In addition, the first doping region 30 and the second doping region 50 are separated by the intrinsic isolation region 40, and no isolation groove is provided, which can also save the process and avoid the damage to each film layer during grooving.
[0088] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.
[0089] The above-described embodiments only represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the utility model patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the utility model patent shall be subject to the appended claims.
Claims
1. A back contact battery, characterized in that: include: substrate; as well as A first functional film layer is provided on the first side of the substrate, the first functional film layer comprises a first doped region and a second doped region which are alternately and insulated and isolated along a preset direction, and the types of doping elements of the first doped region and the second doped region are different; In which, in the surface of the first side of the substrate, a first groove and a second groove are respectively provided at positions corresponding to the first doping region and the second doping region, and the depth of the first groove is greater than the depth of the second groove, so that the thickness dimension of the first doping region is greater than the thickness dimension of the second doping region.
2. The back contact cell according to claim 1, characterized in that: An intrinsic isolation region is provided between each adjacent first doping region and second doping region.
3. The back contact battery according to claim 2, characterized in that: A surface of the first functional film layer facing away from the substrate forms a plane.
4. The back contact cell according to claim 2, characterized in that: The back contact battery further includes a tunneling oxide layer, which is located between the substrate and the first functional film layer, and a portion of the structure of the tunneling oxide layer is located in the first groove and the second groove.
5. The back contact cell according to claim 4, characterized in that: The thickness of the first functional film layer is 300-500 nanometers, and the difference between the thickness of the first doped region and the thickness of the second doped region is 100 nanometers; the thickness of the tunneling oxide layer is 0.1-10 nanometers, the depth of the first groove is 150-250 nanometers, and the depth of the second groove is 100-200 nanometers.
6. The back contact cell according to claim 5, characterized in that: The width of the intrinsic isolation region along the preset direction is 50-100 microns, and the width of the first doped region and the second doped region along the preset direction are both 100-200 microns.
7. The back contact cell according to any one of claims 1 to 6, characterized in that: The bottom walls of the first groove and the second groove are perpendicular to the thickness direction of the substrate.
8. The back contact cell according to any one of claims 1 to 6, characterized in that: The first groove and the second groove are configured as strip grooves. In the projection of the first functional film layer on the substrate, the outer contour of the projection of the first doped region coincides with the outer contour of the first groove, and the outer contour of the projection of the second doped region coincides with the outer contour of the second groove.
9. The back contact cell according to any one of claims 1 to 6, characterized in that: The first doped region is doped with a P-type element, and the second doped region is doped with an N-type element.
10. A photovoltaic module, characterized in that: Comprising at least one battery string, the battery string comprising at least two back-contact batteries according to any one of claims 1-9.