Back contact cells and their fabrication methods, tandem cells and photovoltaic modules

Abstract

This application relates to a back-contact solar cell and its fabrication method, a tandem solar cell, and a photovoltaic module. The back-contact solar cell includes a substrate, a tunneling layer, a first doped layer, a barrier dielectric layer, and a second doped layer. The substrate has a first surface; the first surface includes alternating first and second regions. The substrate includes at least a first dopant element, and the tunneling layer is disposed on the first region. The first doped layer is disposed on at least a portion of the tunneling layer away from the substrate, and the first doped layer includes a first dopant element and a second dopant element; the first and second dopant elements are elements from the same group; the barrier dielectric layer is at least disposed on the second region; the second doped layer is disposed on the side of the barrier dielectric layer away from the substrate, and includes a third dopant element, the third dopant element having a different doping type than the first dopant element. This method can improve the passivation effect of the first region while also maintaining the passivation contact performance of the second region.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to back contact cells and their preparation methods, tandem cells and photovoltaic modules. Background Technology

[0002] Back contact batteries (BC batteries) are a type of solar cell technology that integrates positive and negative metal contacts on the same surface.

[0003] In related technologies, improving the passivation performance of back contact batteries has become one of the future development directions. Summary of the Invention

[0004] Therefore, it is necessary to provide a back contact battery and its preparation method, a tandem battery and a photovoltaic module to address the above technical problems, which can improve the passivation performance of the back contact battery.

[0005] According to a first aspect of this application, a back-contact battery is provided, comprising a substrate, a tunneling layer, a first doped layer, a barrier dielectric layer, and a second doped layer. The substrate has a first surface; the first surface includes alternating first regions and second regions. The substrate includes at least a first dopant element, and the tunneling layer is disposed on the first region. The first doped layer is disposed on the side of the tunneling layer away from the substrate, and the first doped layer includes a first dopant element and a second dopant element; the first dopant element and the second dopant element are elements of the same group; the barrier dielectric layer is at least disposed on the second region; the second doped layer is disposed on the side of the barrier dielectric layer away from the substrate, and includes a third dopant element, the third dopant element having a different doping type than the first dopant element.

[0006] In one embodiment, the thickness of the tunneling layer is less than the thickness of the barrier medium layer.

[0007] In one embodiment, the barrier dielectric layer includes at least one of an amorphous silicon layer, a microcrystalline silicon layer, and a nanocrystalline silicon layer.

[0008] In one embodiment, the barrier dielectric layer includes multiple sub-barrier layers, which are one of amorphous silicon layers, microcrystalline silicon layers, and nanocrystalline silicon layers.

[0009] In one embodiment, the tunneling layer includes a first doping element; the doping concentration of the first doping element in the tunneling layer is greater than the doping concentration of the first doping element in the first doped layer.

[0010] In one embodiment, the doping concentration of the first dopant element in the tunneling layer is 2 × 10⁻⁶. 16 atom / cm 3 -5×10 18 atom / cm 3 .

[0011] In one embodiment, the doping concentration of the first dopant element in the first doped layer is 2 × 10⁻⁶. 15 atom / cm 3 -4×10 18 atom / cm 3 .

[0012] In one embodiment, the tunneling layer includes a first doping element; the doping concentration of the first doping element in the tunneling layer is greater than the doping concentration of the first doping element in the substrate.

[0013] In one embodiment, the first doped layer includes a first portion and a second portion, which are disposed closer to the tunneling layer in the direction from the tunneling layer to the substrate, compared to the second portion; the doping concentration of the first dopant element in the first portion is greater than the doping concentration of the first dopant element in the second portion.

[0014] In one embodiment, the ratio of the average doping concentration of the first dopant element in the first portion to the average doping concentration of the first dopant element in the second portion is 5-15.

[0015] In one embodiment, the back contact battery further includes an oxide layer and a third doped layer, wherein the oxide layer is disposed on the side of the first doped layer away from the tunneling layer, and the third doped layer is disposed on the side of the oxide layer away from the first doped layer.

[0016] In one embodiment, the thickness of the tunneling layer is greater than the thickness of the oxide layer.

[0017] In one embodiment, the density of the tunneling layer is less than that of the oxide layer.

[0018] In one embodiment, a portion of the barrier dielectric layer is disposed on the second region, and another portion of the barrier dielectric layer is disposed on the side of the first doped layer away from the tunneling layer.

[0019] In one embodiment, the substrate further has a second surface disposed opposite to the first surface; the second region is disposed closer to the second surface than the first region.

[0020] According to a second aspect of this application, a method for fabricating a back contact battery is provided, comprising: providing a substrate: wherein the substrate has a first surface; the first surface includes alternating first regions and second regions; the substrate includes at least a first dopant element; forming an initial tunneling layer on the first surface; forming a first semiconductor layer including a second dopant element on at least a portion of the initial tunneling layer away from the substrate; wherein the first dopant element and the second dopant element are elements of the same group; removing portions of the initial tunneling layer and the first semiconductor layer located in the second region to form a tunneling layer and a first dopant layer; forming a barrier dielectric layer at least disposed on the second region, and forming a second dopant layer disposed on the side of the barrier dielectric layer away from the substrate; wherein the second dopant layer includes a third dopant element, the third dopant element having a different doping type than the first dopant element.

[0021] In one embodiment, in the step of forming a first semiconductor layer comprising a second doped element on at least a portion of the side of the initial tunneling layer away from the substrate: the deposition temperature of the first semiconductor layer is in the range of 500°C to 650°C; and / or, the diffusion temperature of the second doped element into the first semiconductor layer is in the range of 700°C to 900°C.

[0022] In one embodiment, in the step of forming at least a barrier dielectric layer on the second region, the deposition temperature of the barrier dielectric layer is less than 200°C; and / or, in the step of forming a second doped layer on the side of the barrier dielectric layer away from the substrate, the deposition temperature of the second doped layer is less than 200°C.

[0023] According to a third aspect of this application, a stacked battery is provided, including a back contact battery of any of the above embodiments or a back contact battery prepared by the preparation method of the back contact battery of any of the above embodiments.

[0024] According to a fourth aspect of this application, a photovoltaic module is provided, including a back contact cell of any of the above embodiments, a back contact cell prepared by the preparation method of the back contact cell of any of the above embodiments, or the above-described stacked cell.

[0025] In the technical solution of this application, on the one hand, the substrate includes at least a first dopant element, which can overflow to a certain extent into the tunneling layer and the first doped layer of the first region, which is beneficial to improving the passivation effect of the first region and also improves the carrier transport performance of the first region. On the other hand, the second region is provided with a barrier dielectric layer, which can improve the passivation effect of the second region, reduce the probability of the first dopant element diffusing to the second doped layer, and also reduce the probability of the third dopant element diffusing to the substrate; thus, while improving the passivation effect of the first region, the passivation contact performance of the second region can also be taken into account. Attached Figure Description

[0026] Figure 1 A schematic diagram of the back contact battery in one embodiment of this application is shown.

[0027] Figure 2 A schematic diagram of the structure of the first doped layer in one embodiment of this application is shown.

[0028] Figure 3 A schematic diagram of the structure of the substrate, initial tunneling layer, first semiconductor layer and phosphosilicate glass in one embodiment of this application is shown.

[0029] Figure 4 This illustration shows a step of the preparation method of a back contact battery according to an embodiment of the present application.

[0030] Figure 5 This illustration shows another step in the preparation method of the back contact battery according to one embodiment of the present application.

[0031] Figure 6 This illustration shows a process diagram of another step in the preparation method of the back contact battery according to an embodiment of this application.

[0032] Figure 7 A schematic diagram of the back contact battery in another embodiment of this application is shown.

[0033] Figure 8 A schematic diagram of the structure of a stacked battery according to an embodiment of this application is shown.

[0034] Figure 9 A circuit diagram of the bottom battery and top battery according to an embodiment of this application is shown.

[0035] Figure 10 A schematic diagram of the structure of a photovoltaic module according to an embodiment of this application is shown.

[0036] Figure label:

[0037] The battery 10 comprises a substrate 110 and 210, a first surface 111 and 211, a first region 1111 and 2111, a second region 1112 and 2112, a second surface 112 and 212, tunneling layers 121 and 221, an initial tunneling layer 1210, a first doped layer 131 and 231, a first semiconductor layer 1310, barrier dielectric layers 122 and 222, an initial barrier dielectric layer 1220, a second doped layer 132 and 232, an initial doped layer 1320, a first portion 1311, a second portion 1312, a first electrode 141 and 241, a second electrode 142 and 242, a first transparent conductive layer 151 and 251, a second transparent conductive layer 152 and 252, a passivation layer 161 and 261, an antireflection layer 162 and 262, a phosphosilicate glass 170, a mask layer 180, an oxide layer 223, and a third doped layer 233.

[0038] Composite layer 20;

[0039] Top battery 30;

[0040] Battery string 101;

[0041] Encapsulation layer 40;

[0042] First cover plate 51, second cover plate 52. Detailed Implementation

[0043] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0044] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0045] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0046] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0047] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0048] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0049] In the accompanying drawings, the thicknesses of layers, films, regions, substrates, etc., are exaggerated for clarity. Throughout the specification, the same reference numerals refer to the same elements. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it may be directly on the other element or there may be intervening elements. Conversely, when an element is referred to as being "directly on" another element, there are no intervening elements.

[0050] Those within the measurement tolerance or manufacturing error range shall be considered substantially identical.

[0051] As described in the background section, improving the passivation performance of back contact batteries has become one of the future development directions. Therefore, this application designs a back contact battery and its preparation method, a tandem battery and a photovoltaic module, aiming to improve the passivation performance of the back contact battery.

[0052] Figure 1 A schematic diagram of the back contact battery in one embodiment of this application is shown.

[0053] Please see Figure 1 One embodiment of this application provides a back contact battery, which includes a substrate 110, a tunneling layer 121, a first doped layer 131, a barrier dielectric layer 122, and a second doped layer 132.

[0054] The substrate 110 has a first surface 111 and a second surface 112 disposed opposite to each other, specifically, the first surface 111 and the second surface 112 are disposed opposite to each other along a first direction F1. The first surface 111 includes alternating first regions 1111 and second regions 1112, and the substrate 110 includes at least a first doped element. A tunneling layer 121 is disposed on the first region 1111, and a first doped layer 131 is disposed on the side of the tunneling layer 121 away from the substrate 110. The first doped layer 131 includes a first doped element and a second doped element, which are elements of the same group. A barrier dielectric layer 122 is disposed at least on the second region 1112, and a second doped layer 132 is disposed on the side of the barrier dielectric layer 122 away from the substrate 110, and includes a third doped element, the third doped element having a different doping type than the first doped element.

[0055] The substrate 110 can be made of a semiconductor material. Optionally, common semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium arsenide, perovskite, cadmium telluride, or copper indium selenide; the substrate 110 can also be a sapphire substrate, a silicon-on-insulator substrate, or a germanium-on-insulator substrate.

[0056] The first surface 111 is usually the back surface, so the first surface 111 can also be called the back side; however, with the development of back contact battery technology, the first surface 111 may also receive the energy of sunlight, mainly from the light reflected or scattered by the surrounding environment.

[0057] The second surface 112 is usually a light-receiving surface (specifically, the light-receiving surface refers to the side surface on the back contact battery that is mainly used to receive sunlight). The second surface 112 can also be called the front surface.

[0058] At least a portion of the first surface 111 and the second surface 112 can both employ a textured structure, thereby increasing the light absorption area and photocurrent, and thus improving the efficiency of the solar cell.

[0059] Figure 1 An exemplary illustration shows that the second surface 112 has a textured structure. This textured structure can be a pyramidal textured structure, which can not only reduce the reflectivity of the second surface 112, but also form light traps, thereby enhancing the absorption effect of the substrate 110 and improving the conversion efficiency of the back contact battery.

[0060] The first region 1111 may have a polished structure. Setting the first region 1111 as a polished structure is beneficial to improving the uniformity of the tunneling layer 121 located in the first region 1111. That is, the thickness of each region in the tunneling layer 121 is not significantly different, thereby improving the passivation effect of the first region 1111.

[0061] The first region 1111 may refer to the region on the first surface 111 that is disposed opposite to the first doped layer 131 along the first direction F1, or it can be understood as the region where the orthogonal projection of the first doped layer 131 is located on the first surface 111, that is, the first region 1111 and the first doped layer 131 are disposed overlapping along the first direction F1.

[0062] The second region 1112 may refer to the region where the first surface 111 is disposed opposite to at least a portion of the second doped layer 132 along the first direction F1, or it can be understood as the region where the orthogonal projection of at least a portion of the second doped layer 132 is located on the first surface 111, that is, at least a portion of the second doped layer 132 overlaps with the second region 1112 along the first direction F1.

[0063] The first region 1111 and the second region 1112 can be arranged alternately along a preset direction, which can be perpendicular to the first direction F1.

[0064] It is understood that, along a preset direction, all regions adjacent to the first region 1111 are second regions 1112. For example, when there are multiple first regions 1111 and multiple second regions 1112, the multiple first regions 1111 and multiple second regions 1112 can be arranged alternately along the preset direction. They can be arranged alternately along the preset direction in the order of first region 1111, second region 1112, first region 1111, second region 1112, first region 1111 and second region 1112, etc.; or they can be arranged alternately along the preset direction in the order of second region 1112, first region 1111, second region 1112, first region 1111, second region 1112 and first region 1111, etc.; no specific restrictions are made here.

[0065] For example, if there are two first regions 1111 and one second region 1112, they can be arranged alternately in the order of first region 1111, second region 1112 and first region 1111 along a preset direction.

[0066] The first region 1111 and the second region 1112 are arranged according to specific uses, and no specific limitation is made here. In addition, the width of the first region 1111 and the second region 1112 in the preset direction can also be set according to actual usage requirements, and no specific limitation is made here.

[0067] "Substrate 110 includes at least a first doping element" can mean that substrate 110 includes a first doping element; "Substrate 110 includes at least a first doping element" can also mean that substrate 110 includes a first doping element and a second doping element; no specific limitation is made here.

[0068] It is possible that one of the second and third doping elements is p-type, and the other of the second and third doping elements is n-type. For example, the first and second doping elements are both n-type, and the third doping element is p-type.

[0069] The first dopant element can be one of nitrogen, antimony, phosphorus, arsenic, and bismuth, and the second dopant element can be another of nitrogen, antimony, phosphorus, arsenic, and bismuth, as long as the first and second dopant elements are elements of the same group. For example, the first dopant element is antimony, and the second dopant element is phosphorus.

[0070] For example, the third dopant element is boron, aluminum, or gallium.

[0071] The tunneling layer 121 is used to achieve interface passivation of the first region 1111 of the first surface 111 of the substrate 110, thereby achieving the effect of chemical passivation. Specifically, by saturating the dangling bonds of the first region 1111 of the first surface 111, the interface trapped state density of the first region 1111 of the first surface 111 is reduced, thereby reducing the carrier recombination rate of the first region 1111 of the first surface 111.

[0072] The material of the tunneling layer 121 can be a dielectric material, such as at least one of silicon oxide, silicon oxynitride, aluminum oxide, or titanium oxide.

[0073] In the embodiments of this application, the tunneling layer 121 can be formed using low-pressure chemical vapor deposition (LPCVD). Of course, other processes such as thermal oxidation, plasma oxidation, or nitric acid oxidation can also be used to fabricate the tunneling layer 121, and no specific limitation is made here.

[0074] The material of the first doped layer 131 can be doped polycrystalline silicon including a first doping element and a second doping element. The first doped layer 131 may also include at least one element selected from oxygen, carbon, and nitrogen.

[0075] The barrier dielectric layer 122 refers to the dielectric layer used to prevent the diffusion of the first dopant element into the second doped layer 132. The material of the barrier dielectric layer 122 may include one or more of amorphous silicon, microcrystalline silicon, and nanocrystalline silicon.

[0076] The material of the second doped layer 132 includes doped amorphous silicon. Thus, the second doped layer 132 can be formed by a low-temperature deposition process, which is more conducive to reducing the probability of the first doped element diffusing to the second doped layer 132 and also reduces the probability of the third doped element diffusing to the substrate 110, thereby improving the passivation effect of the second region 1112.

[0077] The thickness of the second doped layer 132 can be 14nm-45nm.

[0078] For example, the thickness of the second doped layer 132 can be 14 nm, 20 nm, 25 nm, 30 nm, 35 nm, or 45 nm. No specific limitation is made here.

[0079] In the technical solution of this application, on the one hand, the substrate 110 includes at least a first dopant element. The first dopant element can overflow to a certain extent into the tunneling layer 121 and the first doped layer 131 of the first region 1111, which is beneficial to improving the passivation effect of the first region 1111 and also improves the carrier transport performance of the first region 1111. On the other hand, the second region 1112 is provided with a barrier dielectric layer 122, which can improve the passivation effect of the second region 1112, reduce the probability of the first dopant element diffusing to the second doped layer 132, and reduce the probability of the third dopant element diffusing to the substrate 110. Thus, while improving the passivation effect of the first region 1111, the passivation contact performance of the second region 1112 can also be taken into account.

[0080] Furthermore, the interface between the tunneling layer 121 and the substrate 110 contains dangling bonds and fixed charges caused by lattice mismatch. The first dopant element can accumulate at the interface between the tunneling layer 121 and the substrate 110, thereby neutralizing the positively charged defect states at the interface. This neutralization mechanism is independent of hydrogen passivation, is more stable in high-temperature processes, and is not prone to degradation, which is beneficial to improving the passivation effect of the first region 1111.

[0081] In some embodiments, the thickness of the tunneling layer 121 is less than the thickness of the barrier medium layer 122.

[0082] On the one hand, the relatively small thickness of the tunneling layer 121 is conducive to the enrichment of the first doped element in the tunneling layer 121 and also conducive to the spillover of the first doped element to the first doped layer 131, thereby improving the passivation effect of the first region 1111 and the carrier transport performance of the first region 1111. On the other hand, the relatively large thickness of the barrier dielectric layer 122 can reduce the probability of the first doped element diffusing to the second doped layer 132, thereby improving the passivation effect of the barrier dielectric layer 122.

[0083] In some embodiments, the ratio of the thickness of the barrier medium layer 122 to the thickness of the tunneling layer 121 is 2.5-60.

[0084] For example, the ratio of the thickness of the barrier medium layer 122 to the thickness of the tunneling layer 121 is 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60, etc.

[0085] By controlling the ratio of the thickness of the barrier dielectric layer 122 to the thickness of the tunneling layer 121 within a suitable range, it is beneficial for the first doped element to overflow into the first doped layer 131, thereby improving the passivation contact performance of the first region 1111 and reducing the probability of the first doped element diffusing into the second doped layer 132, thus improving the passivation effect of the barrier dielectric layer 122.

[0086] Furthermore, the ratio of the thickness of the barrier medium layer 122 to the thickness of the tunneling layer 121 is 5-40, for example, the ratio of the thickness of the barrier medium layer 122 to the thickness of the tunneling layer 121 is 5, 10, 15, 20, 25, 30, 35 or 40, etc.

[0087] Furthermore, the ratio of the thickness of the barrier medium layer 122 to the thickness of the tunneling layer 121 is 10-30. For example, the ratio of the thickness of the barrier medium layer 122 to the thickness of the tunneling layer 121 is 10, 12.5, 15, 17.5, 20, 22.5, 25, 27.5 or 30, etc.

[0088] In this way, the passivation contact performance of the first region 1111 can be improved, and the probability of the first dopant element diffusing to the second doped layer 132 can be reduced, thereby improving the passivation effect of the barrier dielectric layer 122.

[0089] In some embodiments, the thickness of the tunneling layer 121 can be 0.5 nm to 2 nm. For example, the thickness of the tunneling layer 121 can be 0.5 nm, 1 nm, 1.5 nm, or 2 nm, etc.

[0090] By controlling the thickness of the tunneling layer 121, it is possible to achieve a certain passivation effect while also facilitating the overflow of the first doped element into the first doped layer 131, thereby improving the passivation effect of the first region 1111 and also enhancing the carrier transport performance of the first region 1111.

[0091] In some embodiments, the thickness of the barrier dielectric layer 122 can be 5nm-30nm.

[0092] For example, the thickness of the barrier dielectric layer 122 is 5 nm, 10 nm, 15 nm, 20 nm, 25 nm or 30 nm.

[0093] This configuration reduces the probability of the first doped element diffusing into the second doped layer 132, thereby improving the passivation effect of the barrier dielectric layer 122.

[0094] In some embodiments, the density of the barrier medium layer 122 is greater than the density of the tunneling layer 121.

[0095] On the one hand, the low density of the tunneling layer 121 is conducive to the enrichment of the first dopant element in the tunneling layer 121 and also conducive to the spillover of the first dopant element to the first doped layer 131, thereby improving the passivation effect of the first region 1111 and the carrier transport performance of the first region 1111. On the other hand, the high density of the barrier dielectric layer 122 can reduce the probability of the first dopant element diffusing to the second doped layer 132, thereby improving the passivation effect of the barrier dielectric layer 122.

[0096] In some embodiments, the barrier dielectric layer 122 includes at least one of an amorphous silicon layer, a microcrystalline silicon layer, and a nanocrystalline silicon layer.

[0097] The barrier dielectric layer 122 may include one of the following: an amorphous silicon layer, a microcrystalline silicon layer, and a nanocrystalline silicon layer.

[0098] Alternatively, the barrier dielectric layer 122 may include multiple sub-barrier layers, which may be one of an amorphous silicon layer, a microcrystalline silicon layer, or a nanocrystalline silicon layer.

[0099] Among them, the amorphous silicon layer can be a hydrogen-doped amorphous silicon layer or an oxygen-doped amorphous silicon layer; the microcrystalline silicon layer can be a hydrogen-doped microcrystalline silicon layer or an oxygen-doped microcrystalline silicon layer; and the nanocrystalline silicon layer can be a hydrogen-doped nanocrystalline silicon layer or an oxygen-doped nanocrystalline silicon layer.

[0100] Since the barrier dielectric layer 122 includes at least one of an amorphous silicon layer, a microcrystalline silicon layer, and a nanocrystalline silicon layer, and the combination of the amorphous silicon layer, the microcrystalline silicon layer, and the nanocrystalline silicon layer has good compactness, the barrier dielectric layer 122 with higher compactness can better reduce the probability of the first dopant element diffusing to the second doped layer 132, and can also reduce the probability of the third dopant element diffusing to the substrate 110, thereby improving the passivation contact performance of the second region 1112.

[0101] When the barrier dielectric layer 122 includes multiple sub-barrier layers, the pores of the previous sub-barrier layer can be filled by the setting of the subsequent sub-barrier layer, thereby improving the density of the barrier dielectric layer 122. This can better reduce the probability of the first dopant element diffusing to the second doped layer 132 and the probability of the third dopant element diffusing to the substrate 110, thereby improving the passivation contact performance of the second region 1112.

[0102] Furthermore, when the materials of the multiple sub-blocking layers of the barrier dielectric layer 122 are different, the barrier dielectric layer 122 can have a good passivation effect through the combination of multiple sub-blocking layers.

[0103] In some embodiments, the barrier dielectric layer 122 includes oxygen, that is, the barrier dielectric layer 122 includes at least one of an oxygen-doped amorphous silicon layer, an oxygen-doped microcrystalline silicon layer, and an oxygen-doped nanocrystalline silicon layer.

[0104] When the barrier dielectric layer 122 includes oxygen, the surface of the barrier dielectric layer 122 has a very shallow concentration of oxygen doping, which can effectively improve the passivation effect of the barrier dielectric layer 122.

[0105] In some embodiments, the doping concentration of the first dopant element in the second doped layer 132 is greater than or equal to zero and less than or equal to 1 × 10⁻⁶. 2 atom / cm 3 .

[0106] The doping concentration of the first dopant element in the second doped layer 132 can be zero, approach zero, or 10 atom / cm². 3 wait.

[0107] It can be understood that the first doping element hardly diffused to the barrier dielectric layer 122 and the second doped layer 132. Thus, using a substrate 110 containing the first doping element is beneficial to improving the passivation performance of the first region 1111 while also taking into account the passivation performance of the second region 1112.

[0108] In some embodiments, the second region 1112 has a first texture structure (such as...) Figure 1 As shown), setting a texture structure in the second region 1112 is beneficial to improving the light trapping effect of the second region 1112, so as to further increase the density of photogenerated carriers.

[0109] In some embodiments, the second surface 112 has a second texture structure, and the size of the first texture structure is smaller than the size of the second texture structure (not shown in the figure) along the first direction F1. Both the first texture structure and the second texture structure are pyramidal in shape.

[0110] Thus, the smaller size of the first texture structure along the first direction F1 is beneficial to improving the light trapping effect of the second region 1112 while also ensuring the deposition uniformity of the barrier dielectric layer 122, thereby increasing the density of the barrier dielectric layer 122. This can effectively reduce the probability of the first dopant element diffusing to the second doped layer 132 and the probability of the third dopant element diffusing to the substrate 110, thereby improving the passivation contact performance of the second region 1112.

[0111] In some embodiments, the first texture structure includes a first pyramidal structure, the size of which along the first direction F1 ranges from 0.1 micrometers to 3 micrometers. The second texture structure includes a second pyramidal structure, the size of which along the first direction F1 ranges from 1 micrometer to 5 micrometers.

[0112] In other embodiments, the first texture structure includes multiple platform structures, which are equivalent to the base of a pyramid-shaped structure. That is, the platform structure is equivalent to a raised platform with a flat surface formed after the top part of the pyramid-shaped structure is cut off. For example, the height of the platform structure is one-quarter to one-fifth of the height of the second pyramid-shaped structure.

[0113] Wherein, the height of the platform structure is the dimension of the platform structure along the first direction F1, and the height of the second pyramid-shaped structure is the dimension of the second pyramid-shaped structure along the first direction F1.

[0114] The first texture structure can be obtained through a polishing process. This improves the deposition uniformity of the barrier medium layer 122, thereby increasing the density of the barrier medium layer 122 and enhancing the light-trapping effect of the second region 1112.

[0115] In some embodiments, the tunneling layer 121 includes a first doping element, and the doping concentration of the first doping element in the tunneling layer 121 is greater than the doping concentration of the first doping element in the substrate 110.

[0116] Alternatively, the doping concentration of the first dopant element in the tunneling layer 121 can be greater than the doping concentration of the first dopant element in the substrate 110; or the average doping concentration of the first dopant element in the tunneling layer 121 can be greater than the doping concentration of the first dopant element in the substrate 110; or the average doping concentration of the first dopant element in the tunneling layer 121 can be greater than the average doping concentration of the first dopant element in the substrate 110. In this way, the first dopant element can fill the voids in the tunneling layer 121, thereby effectively improving the passivation effect of the tunneling layer 121, and thus improving the passivation contact performance of the first region 1111.

[0117] The average doping concentration of the first dopant element in the tunneling layer 121 refers to the average doping concentration of the first dopant element in different depth regions of the tunneling layer 121.

[0118] The average doping concentration of the first dopant element in the substrate 110 refers to the average doping concentration of the first dopant element in different depth regions of the substrate 110.

[0119] Under the same test conditions (such as the same sputtering rate and the same ion beam parameters, etc.), the doping concentration of the first dopant element in the tunneling layer 121 and the doping concentration of the first dopant element in the substrate 110 can be detected by secondary ion mass spectrometry (SIMS) technology. The depth distribution curve, surface distribution image and / or line scan spectrum corresponding to the first dopant element can be obtained, from which the average doping concentration or integral doping amount of the first dopant element can be extracted.

[0120] In some embodiments, the doping concentration of the first dopant element in the tunneling layer 121 is greater than the doping concentration of the first dopant element in the first doped layer 131.

[0121] Alternatively, the doping concentration of the first doped element in the tunneling layer 121 may be greater than the doping concentration of the first doped element in the first doped layer 131; or the average doping concentration of the first doped element in the tunneling layer 121 may be greater than the doping concentration of the first doped element in the first doped layer 131; or the average doping concentration of the first doped element in the tunneling layer 121 may be greater than the average doping concentration of the first doped element in the first doped layer 131.

[0122] The average doping concentration of the first dopant element in the first doped layer 131 refers to the average doping concentration of the first dopant element in different depth regions of the first doped layer 131.

[0123] On the one hand, the high doping concentration of the first dopant element in the tunneling layer 121 effectively enhances the passivation effect of the tunneling layer 121, thereby improving the carrier transport performance of the first region 1111. On the other hand, the first doped layer 131 includes a first dopant element and a second dopant element, which is beneficial to improving the carrier transport performance of the first region 1111 and reducing the resistance of the back contact battery. Furthermore, when the first dopant element is antimony, it also has the characteristic of not easily migrating during high-temperature processing, thereby improving the reliability of the back contact battery.

[0124] As described above, under the same test conditions (such as the same sputtering rate and the same ion beam parameters, etc.), the doping concentration of the first dopant element in the tunneling layer 121 and the doping concentration of the first dopant element in the first doped layer 131 can be detected by secondary ion mass spectrometry (SIMS) technology, thereby obtaining the relationship between the doping concentration of the first dopant element in the tunneling layer 121 and the doping concentration of the first dopant element in the first doped layer 131, and also the relationship between the average doping concentration of the first dopant element in the tunneling layer 121 and the average doping concentration of the first dopant element in the first doped layer 131.

[0125] In some embodiments, the doping concentration of the first dopant element in the tunneling layer 121 is greater than the doping concentration of the first dopant element in the substrate 110. Furthermore, the doping concentration of the first dopant element in the tunneling layer 121 is greater than the doping concentration of the first dopant element in the first doped layer 131.

[0126] It is understandable that the aggregation of the first dopant element in the tunneling layer 121 can effectively improve the passivation effect of the tunneling layer 121, thereby improving the passivation contact performance of the first region 1111.

[0127] In some embodiments, the doping concentration of the first dopant element in the first doped layer 131 is less than the doping concentration of the second dopant element in the first doped layer 131.

[0128] Alternatively, the doping concentration of the first dopant element in the first doped layer 131 may be less than the doping concentration of the second dopant element in the first doped layer 131; or the doping concentration of the first dopant element in the first doped layer 131 may be less than the average doping concentration of the second dopant element in the first doped layer 131; or the average doping concentration of the first dopant element in the first doped layer 131 may be less than the average doping concentration of the second dopant element in the first doped layer 131.

[0129] The average doping concentration of the second dopant element in the first doped layer 131 refers to the average doping concentration of the second dopant element in different depth regions of the first doped layer 131.

[0130] As described above, under the same test conditions (such as the same sputtering rate and the same ion beam parameters, etc.), the doping concentration of the first dopant element in the first doped layer 131 and the doping concentration of the second dopant element in the first doped layer 131 can be detected by secondary ion mass spectrometry (SIMS) technology, thereby obtaining the relationship between the doping concentration of the first dopant element in the first doped layer 131 and the doping concentration of the second dopant element in the first doped layer 131, and also the relationship between the average doping concentration of the first dopant element in the first doped layer 131 and the average doping concentration of the second dopant element in the first doped layer 131.

[0131] The first doped layer 131 is mainly composed of the second doping element, which makes it easy to control the doping uniformity of the second doping element in the first doped layer 131 through the process of the second doping element, thereby facilitating precise control of electrical parameters and improving device consistency and stability.

[0132] In some embodiments, the doping concentration of the first dopant element in the tunneling layer 121 is 2 × 10⁻⁶. 16 atom / cm 3 -5×10 18 atom / cm 3 .

[0133] For example, the doping concentration of the first dopant element in the tunneling layer 121 is 2 × 10⁻⁶. 16 atom / cm 3 2.5×10 16 atom / cm 3 6×10 16 atom / cm 3 1.1×10 17 atom / cm 35×10 17 atom / cm 3 1.1×10 18 atom / cm 3 3.1×10 18 atom / cm 3 Or 5×10 18 atom / cm 3 wait.

[0134] In some embodiments, the doping concentration of the first dopant element in the substrate 110 is 0.9 × 10⁻⁶. 14 atom / cm 3 -5×10 16 atom / cm 3 .

[0135] For example, the doping concentration of the first dopant element in the substrate 110 is 0.9 × 10⁻⁶. 14 atom / cm 3 1×10 15 atom / cm 3 7×10 15 atom / cm 3 1×10 16 atom / cm 3 Or 5×10 16 atom / cm 3 wait.

[0136] It can be seen that the first dopant element has a high doping concentration in the tunneling layer 121, thus effectively improving the passivation effect of the tunneling layer 121.

[0137] In some embodiments, the doping concentration of the first dopant element in the first doped layer 131 is 2 × 10⁻⁶. 15 atom / cm 3 -4×10 18 atom / cm 3 .

[0138] For example, the doping concentration of the first doped element in the first doped layer 131 is 2 × 10⁻⁶. 15 atom / cm 3 1×10 16 atom / cm 3 1×10 17 atom / cm 3 Or 4×10 18 atom / cm 3 wait.

[0139] The first doping element has a certain doping concentration in the first doped layer 131, which is beneficial to improving the carrier transport performance of the first region 1111 and reducing the resistance of the back contact battery.

[0140] In some embodiments, the doping concentration of the second dopant element in the first doped layer 131 is 1×10⁻⁶. 19 atom / cm 3 -3×10 20 atom / cm 3 .

[0141] For example, the doping concentration of the second dopant element in the first doped layer 131 is 1 × 10⁻⁶. 19 atom / cm 3 2.5×10 19 atom / cm 3 5×10 19 atom / cm 3 1×10 20 atom / cm 3 Or 3×10 20 atom / cm 3 wait.

[0142] The second dopant element has a certain doping uniformity in the first doped layer 131, which can improve the consistency and stability of the device.

[0143] In some embodiments, such as Figure 2 As shown, the first doped layer 131 includes a first portion 1311 and a second portion 1312. Along the direction from the tunneling layer 121 to the substrate 110, the first portion 1311 is disposed closer to the tunneling layer 121 than the second portion 1312. The doping concentration of the first dopant element in the first portion 1311 is greater than the doping concentration of the first dopant element in the second portion 1312.

[0144] Alternatively, the average doping concentration of the first dopant element in the first part 1311 may be greater than the average doping concentration of the first dopant element in the second part 1312; or the average doping concentration of the first dopant element in the first part 1311 may be greater than the doping concentration of the first dopant element in the second part 1312; or the doping concentration of the first dopant element in the first part 1311 may be greater than the doping concentration of the first dopant element in the second part 1312.

[0145] Secondary ion mass spectrometry (SIMS) can be used to sputter layer by layer from the outside to the inside of the first doped layer 131. The depth distribution curve of the secondary ion mass spectrometry can be obtained. The horizontal axis of the depth distribution curve is the sputtering depth (the unit of sputtering depth is nm or μm), and the vertical axis is the doping concentration (the unit of doping concentration is atom / cm).3 The first part 1311 has a greater sputtering depth than the second part 1312.

[0146] Since the doping concentration of the first dopant element in the first part 1311 is greater than that in the second part 1312, the first dopant element can form a concentration gradient in the first part 1311 and the second part 1312, thereby increasing the conductivity of charge carriers, reducing the resistance of the back contact cell, and thus improving the working efficiency of the back contact cell.

[0147] In some embodiments, the atomic radius of the first dopant element is larger than the atomic radius of the second dopant element.

[0148] For example, the first dopant element is arsenic, antimony, or bismuth, and the second dopant element is phosphorus.

[0149] Thus, driven by the high-temperature diffusion process of the second doped element, the first doped element is "pushed" into the tunneling layer 121. Since the atomic radius of the first doped element is larger and the atomic radius of the second doped element is smaller, the first doped element with a larger atomic radius occupies the grain boundary and diffusion channel of the tunneling layer 121, and occupies the path for the second doped element to diffuse into the substrate 110, thus inhibiting the diffusion of the second doped element into the substrate 110. This is conducive to the accumulation of the first doped element at the interface between the tunneling layer 121 and the substrate 110, thereby improving the passivation effect of the first region 1111.

[0150] In some embodiments, the thickness of the first doped layer 131 can be 50 nm to 150 nm.

[0151] For example, the thickness of the first doped layer 131 can be 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm or 150nm, etc.

[0152] In some embodiments, the ratio of the average doping concentration of the first dopant element in the first portion 1311 to the average doping concentration of the first dopant element in the second portion 1312 is 5-15.

[0153] The first part 1311 refers to a portion of the first doped layer 131 adjacent to the tunneling layer 121. The thickness of the first part 1311 is 15nm-25nm. For example, the thickness of the first part 1311 can be 15nm, 20nm, or 25nm, etc.

[0154] The second part 1312 refers to a portion of the first doped layer 131 adjacent to the first part 1311. The thickness of the second part 1312 is 15nm-25nm. For example, the thickness of the second part 1312 can be 15nm, 20nm, or 25nm, etc.

[0155] For example, the ratio of the average doping concentration of the first dopant element in the first portion 1311 to the average doping concentration of the first dopant element in the second portion 1312 is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15, etc.

[0156] In terms of process, the ratio of the average doping concentration of the first doped element in the first part 1311 to the average doping concentration of the first doped element in the second part 1312 can be adjusted by controlling the thickness of the first doped layer 131. For example, the thickness of the first doped layer 131 can be set to 50nm-150nm. In this way, the thickness of the first doped layer 131 is set to be relatively small, which is conducive to the incorporation of the second doped element into the first doped layer 131, and also conducive to the incorporation of the first doped element into the first doped layer 131. This allows the ratio of the average doping concentration of the first doped element in the first part 1311 to the average doping concentration of the first doped element in the second part 1312 to be controlled within a suitable range, thereby increasing the conductivity of charge carriers, reducing the resistance of the back contact battery, and thus improving the working efficiency of the back contact battery.

[0157] Furthermore, when the atomic radius of the first dopant element is larger than that of the second dopant element, the average doping concentration of the first dopant element in the first part 1311 is larger, and the first dopant element with a larger atomic radius occupies the grain boundary and diffusion channel of the first part 1311, which to some extent restricts the diffusion of the second dopant element into the tunneling layer 121 and the substrate 110, thereby facilitating the accumulation of the first dopant element at the interface between the tunneling layer 121 and the substrate 110, thus greatly improving the passivation effect of the first region 1111.

[0158] Of course, this application is not limited to this, and the ratio of the average doping concentration of the first dopant element in the first part 1311 to the average doping concentration of the first dopant element in the second part 1312 can also be made to be 5-15 by other means.

[0159] In some embodiments, the first dopant element decreases in the first doped layer 131 from the side near the tunneling layer 121 to the side away from the tunneling layer 121. The first dopant element has a concentration gradient characteristic in the first doped layer 131, which can further increase the conductivity of charge carriers, reduce the resistance of the back contact cell, and thus improve the working efficiency of the back contact cell.

[0160] In some embodiments, a portion of the barrier dielectric layer 122 is disposed on the second region 1112, and another portion of the barrier dielectric layer 122 is disposed on the side of the first doped layer 131 away from the tunneling layer 121.

[0161] The back contact battery also includes a first electrode 141, which is electrically connected to the first doped layer 131.

[0162] Alternatively, the first electrode 141 may be disposed on the portion of the first doped layer 131 where the barrier dielectric layer 122 is not disposed, and may be electrically connected to the first doped layer 131.

[0163] It is understood that a tunneling layer 121 and a first doped layer 131 are first formed on the first region 1111, and then a barrier dielectric layer 122 and a second doped layer 132 are formed on the second region 1112. In this way, the barrier dielectric layer 122 can be used to better electrically isolate the first doped layer 131 and the second doped layer 132, thereby improving the reliability of the back contact battery and reducing the diffusion of the first doped element to the second doped layer 132 due to the doping process of the first doped layer 131.

[0164] In some embodiments, the back contact battery further includes a second electrode 142, which is disposed on the side of the second doped layer 132 away from the substrate 110 and is electrically connected to the second doped layer 132.

[0165] The first electrode 141 and the second electrode 142 are used to collect and summarize the current of the back contact battery.

[0166] In some embodiments, the back contact battery further includes a first transparent conductive layer 151, which is disposed on the side of the first doped layer 131 away from the substrate 110, and a first electrode 141 is disposed on the side of the first transparent conductive layer 151 away from the first doped layer 131.

[0167] In some embodiments, the back contact battery further includes a second transparent conductive layer 152, which is disposed on the side of the second doped layer 132 away from the substrate 110, and the second electrode 142 is disposed on the side of the second transparent conductive layer 152 away from the second doped layer 132.

[0168] The materials of the first transparent conductive layer 151 and the second transparent conductive layer 152 include at least one of indium tin oxide, tungsten-doped indium oxide, titanium-doped indium oxide, tin oxide and aluminum-doped zinc oxide. The first transparent conductive layer 151 and the second transparent conductive layer 152 have light transmittance and conductivity, and have the functions of collecting and conducting current, as well as protecting the interface, which is beneficial to improving the photoelectric conversion efficiency and long-term stability of the back contact battery.

[0169] In some embodiments, the second region 1112 is located closer to the second surface 112 than the first region 1111.

[0170] Specifically, along the first direction F1, the second region 1112 is located closer to the second surface 112 than the first region 1111.

[0171] In other words, when no tunneling layer 121 and barrier medium layer 122 are provided on the first surface 111 of the substrate 110, the distance between the first region 1111 and the second surface 112 is greater than the distance between the second region 1112 and the second surface 112.

[0172] When a portion of the barrier dielectric layer 122 is disposed on the second region 1112 and another portion of the barrier dielectric layer 122 is disposed on the side of the first doped layer 131 away from the tunneling layer 121, the distance between the portion of the barrier dielectric layer 122 disposed on the first doped layer 131 and the second surface 112 is greater than the distance between the portion of the barrier dielectric layer 122 disposed on the second region 1112 and the second surface 112.

[0173] It is understood that before forming the blocking dielectric layer 122, the second region 1112 can be textured to give the second region 1112 a textured structure, thereby improving the light trapping effect of the second region 1112 and further increasing the density of photogenerated carriers.

[0174] In some embodiments, the back contact battery further includes a passivation layer 161 and an antireflection layer 162, wherein the passivation layer 161 is disposed on the side of the second surface 112 away from the first surface 111, and the antireflection layer 162 is disposed on the side of the passivation layer 161 away from the substrate 110.

[0175] The material of the passivation layer 161 includes at least one of silicon dioxide and aluminum oxide.

[0176] The passivation layer 161 can reduce the minority carrier concentration of the second surface 112 by utilizing the passivation effect, suppress carrier recombination, and thereby improve the open-circuit voltage of the back contact battery.

[0177] The antireflection layer 162 is made of at least one of silicon nitride or silicon oxynitride. The antireflection layer 162 can reduce light reflection, increase light absorption, and improve the short-circuit current of the back contact battery.

[0178] One embodiment of this application also provides a method for preparing a back contact battery, comprising:

[0179] S10, Provide a substrate 110. The substrate 110 has a first surface 111; the first surface 111 includes alternating first regions 1111 and second regions 1112. The substrate 110 includes at least a first dopant element.

[0180] S20, an initial tunneling layer 1210 is formed on the first surface 111.

[0181] S30, a first semiconductor layer 1310 comprising a second doped element is formed on at least a portion of the initial tunneling layer 1210 on the side away from the substrate 110.

[0182] The first and second doping elements are elements from the same group.

[0183] For example, the second dopant element is phosphorus. Please refer to [reference needed]. Figure 3 The step of forming a first semiconductor layer 1310 comprising a second doped element on at least a portion of the side of the initial tunneling layer 1210 away from the substrate 110 includes:

[0184] S31, a phosphorus silica glass 170 is formed on the side of the first semiconductor layer 1310 away from the initial tunneling layer 1210.

[0185] S32, Phosphorus in the silicon phosphate glass 170 is diffused to the first semiconductor layer 1310.

[0186] S40, Remove the portion of the initial tunneling layer 1210 and the first semiconductor layer 1310 located in the second region 1112 to form the tunneling layer 121 and the first doped layer 131.

[0187] The step of removing the portions of the initial tunneling layer 1210 and the first semiconductor layer 1310 located in the second region 1112 to form the tunneling layer 121 and the first doped layer 131 includes:

[0188] S41. A mask layer 180 is formed on the side of the phosphosilicate glass 170 away from the first semiconductor layer 1310.

[0189] S42. Please refer to the following: Figure 4 The mask layer 180 is used to remove the portions of the initial tunneling layer 1210 and the first semiconductor layer 1310 that are not covered by the mask layer 180.

[0190] In embodiments of this application, the method for preparing the back contact battery may further include:

[0191] S43. Texture the second region 1112 of the first surface 111 and the second surface 112.

[0192] S44, Remove mask layer 180, Remove phosphosilicate glass 170.

[0193] S45, please refer to the following: Figure 5 A passivation layer 161 is formed on the side of the second surface 112 away from the first surface 111.

[0194] S46. Please refer to the following: Figure 5 An antireflection layer 162 is formed on the side of the passivation layer 161 away from the substrate 110.

[0195] S47. Remove the antireflective material layer deposited synchronously with the antireflective layer 162 and disposed on the first surface 111, and remove the passivation material layer deposited synchronously with the passivation layer 161 and disposed on the first surface 111.

[0196] S50, forming at least a barrier dielectric layer 122 disposed on the second region 1112, and forming a second doped layer 132 disposed on the side of the barrier dielectric layer 122 away from the substrate 110. The second doped layer 132 includes a third doping element, the third doping element having a different doping type than the first doping element.

[0197] For example, please refer to the following: Figure 6 The steps of forming a barrier dielectric layer 122 at least on the second region 1112 and forming a second doped layer 132 on the side of the barrier dielectric layer 122 away from the substrate 110 include:

[0198] S51. An initial barrier dielectric layer 1220 is formed at least on the second region 1112, and an initial doped layer 1320 is formed on the side of the initial barrier dielectric layer 1220 away from the substrate 110. The initial doped layer 1320 includes a doped portion located in the first region 1111, and the initial barrier dielectric layer 1220 includes a barrier dielectric portion located in the first region 1111.

[0199] S52, remove at least a portion of the doped portion and the barrier dielectric portion to obtain the barrier dielectric layer 122 and the second doped layer 132.

[0200] Thus, the first dopant element can diffuse into the tunneling layer 121 and the first doped layer 131 of the first region 1111, which is beneficial to improving the passivation effect of the first region 1111 and also improves the carrier transport performance of the first region 1111. On the other hand, since the second doped layer 132 of the second region 1112 is formed after the first doped layer 131, the impact of the high-temperature process of the second dopant element diffusing into the first semiconductor layer 1310 on the second region 1112 can be reduced. In addition, the second region 1112 is provided with a barrier dielectric layer 122, which can reduce the probability of the first dopant element diffusing into the barrier dielectric layer 122 and the second doped layer 132. This can improve the passivation effect of the second region 1112 while also taking into account the passivation contact performance of the second region 1112.

[0201] It should be noted that, in this application, by controlling the process of the diffusion of the second doped element to the first semiconductor layer 1310, for example, by controlling the diffusion temperature of the second doped element to the first semiconductor layer 1310, or by controlling the diffusion time of the second doped element to the first semiconductor layer 1310, the doping concentration of the first doped element in the tunneling layer 121 can be made greater than the doping concentration of the first doped element in the substrate 110, thereby allowing the first doped element to accumulate in the tunneling layer 121, thereby improving the passivation performance of the first region 1111.

[0202] In some embodiments, the density of the initial tunneling layer 1210 is less than the density of the barrier medium layer 122.

[0203] The density of the initial tunneling layer 1210 and the density of the barrier medium layer 122 can be detected by X-ray reflectance method (XRR) combined with fitting software. Alternatively, the porosity of the initial tunneling layer 1210 and the porosity of the barrier medium layer 122 can be detected by scanning electron microscopy combined with image analysis, thereby determining the relationship between the density of the initial tunneling layer 1210 and the density of the barrier medium layer 122.

[0204] Since the barrier dielectric layer 122 has a high density, the probability of the first doped element diffusing into the second doped layer 132 can be reduced. This also reduces the probability of diffusing the first doped element into the second doped layer 132. While improving the passivation performance of the first region 1111, the passivation contact performance of the second region 1112 can also be taken into account.

[0205] In some embodiments, in the step of forming a first semiconductor layer 1310 including a second doped element on at least a portion of the side of the initial tunneling layer 1210 away from the substrate 110: the deposition temperature of the first semiconductor layer 1310 is in the range of 500°C to 650°C.

[0206] For example, the deposition temperature of the first semiconductor layer 1310 is 500°C, 600°C, or 650°C, etc.

[0207] The deposition temperature of the first semiconductor layer 1310 is set within a suitable range, such as 500℃-650℃. Under normal circumstances, this can improve the uniformity of the first semiconductor layer 1310 (when the first semiconductor layer 1310 is polycrystalline silicon, a suitable deposition temperature is conducive to the formation of fine-grained polycrystalline silicon), thereby giving the first doped layer 131 good doping uniformity and good conductivity, which is beneficial to improving the passivation contact performance of the first region 1111.

[0208] In some embodiments, the diffusion temperature of the second doped element diffuses into the first semiconductor layer 1310 is in the range of 700°C to 900°C.

[0209] For example, the diffusion temperature of the second doped element to the first semiconductor layer 1310 is 700°C, 750°C, 800°C, 850°C, or 900°C, etc.

[0210] The diffusion temperature of the second doped element to the first semiconductor layer 1310 is set within a suitable range, such as 700℃-900℃. This not only helps to reduce the uneven diffusion of the second doped element in the first doped layer 131, but also reduces the possibility of the second doped element entering the substrate 110 through the tunneling layer 121 due to excessively high diffusion temperature. It also allows the doping concentration of the first doped element in the tunneling layer 121 to be greater than that in the substrate 110, thereby enabling the first doped element to accumulate in the tunneling layer 121 and improving the passivation performance of the first region 1111.

[0211] In some embodiments, in the step of forming at least one barrier medium layer 122 disposed on the second region 1112, the deposition temperature of the barrier medium layer 122 is less than 200°C.

[0212] The deposition temperature of the barrier medium layer 122 refers to the deposition temperature of the initial barrier medium layer 1220.

[0213] The deposition temperature of the barrier dielectric layer 122 can be greater than 100°C and less than 200°C. For example, the deposition temperature of the barrier dielectric layer 122 may be 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, or 190°C. A lower deposition temperature of the barrier dielectric layer 122 can further reduce the probability of the first dopant element diffusing to the second doped layer 132, thereby improving the passivation contact performance of the second region 1112.

[0214] In some embodiments, in the step of forming a second doped layer 132 disposed on the side of the barrier dielectric layer 122 away from the substrate 110, the deposition temperature of the second doped layer 132 is less than 200°C.

[0215] The deposition temperature of the second doped layer 132 refers to the deposition temperature of the initial doped layer 1320.

[0216] The deposition temperature of the second doped layer 132 can be greater than 100°C and less than 200°C. For example, the deposition temperature of the second doped layer 132 is 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C or 190°C, etc.

[0217] The second doped layer 132 is formed at a lower temperature, which can further reduce the probability of the first doped element diffusing to the second doped layer 132, thereby improving the passivation contact performance of the second region 1112.

[0218] In some embodiments, the method for preparing a back contact battery further includes:

[0219] S60, a first transparent conductive layer 151 is formed on the side of the first doped layer 131 away from the substrate 110, and a second transparent conductive layer 152 is formed on the side of the second doped layer 132 away from the substrate 110.

[0220] S70, a first electrode 141 is formed on the side of the first transparent conductive layer 151 away from the first doped layer 131, and a second electrode 142 is formed on the side of the second transparent conductive layer 152 away from the second doped layer 132.

[0221] Optionally, the first transparent conductive layer 151 and the second transparent conductive layer 152 are made of the same material and can be formed by the same process, thereby improving the overall manufacturing efficiency of the first transparent conductive layer 151 and the second transparent conductive layer 152 and reducing costs.

[0222] Optionally, the first electrode 141 and the second electrode 142 can be formed under the same process, thereby improving the overall manufacturing efficiency of the first electrode 141 and the second electrode 142 and reducing costs. Figure 7 A schematic diagram of the structure of a back contact battery according to another embodiment of this application is shown.

[0223] Please see Figure 7 Another embodiment of this application provides a back contact battery, which includes a substrate 210, a tunneling layer 221, a first doped layer 231, a barrier dielectric layer 222, and a second doped layer 232.

[0224] The substrate 210 has a first surface 211 and a second surface 212 disposed opposite to each other along a first direction F1. The first surface 211 includes alternating first regions 2111 and second regions 2112. The substrate 210 includes at least a first doped element. A tunneling layer 221 is disposed on the first region 2111, and a first doped layer 231 is disposed on at least a portion of the tunneling layer 221 on the side away from the substrate 210. The first doped layer 231 includes a first doped element and a second doped element, which are elements of the same group. A barrier dielectric layer 222 is disposed at least on the second region 2112, and a second doped layer 232 is disposed on the side of the barrier dielectric layer 222 away from the substrate 210, and includes a third doped element, the third doped element having a different doping type than the first doped element.

[0225] The back contact battery also includes an oxide layer 223 and a third doped layer 233. The oxide layer 223 is disposed on the side of the first doped layer 231 away from the tunneling layer 221, and the third doped layer 233 is disposed on the side of the oxide layer 223 away from the first doped layer 231.

[0226] On the one hand, compared to a thicker tunneling layer 121, this application provides a tunneling layer 221 and an oxide layer 223. This allows for a thinner design of the tunneling layer 221 and / or oxide layer 223, improving the tunneling effect of the tunneling layer 221 and oxide layer 223 while simultaneously providing passivation. This enhances the passivation performance and carrier transport of the back contact battery, thereby improving its electrical performance, such as open-circuit voltage and fill factor. On the other hand, compared to a thicker doped polycrystalline silicon layer, this application can design two thinner first doped layer 231 and third doped layer 233. This is beneficial for increasing the doping concentration of the first doped layer 231 and third doped layer 233, which in turn improves the electrical performance of the back contact battery.

[0227] In some embodiments, a portion of the barrier dielectric layer 222 is disposed on the second region 2112, and another portion of the barrier dielectric layer 222 is disposed on the side of the third doped layer 233 away from the oxide layer 223.

[0228] In some embodiments, the thickness of the tunneling layer 221 is 0.1 nm to 2 nm.

[0229] For example, the thickness of the tunneling layer 221 is 0.1 nm, 0.2 nm, 0.4 nm, 0.5 nm, 1 nm, 1.5 nm or 2 nm, etc.

[0230] The thickness of the tunneling layer 221 can be designed to be thinner, thereby improving the tunneling effect of the tunneling layer 221.

[0231] In some embodiments, the thickness of the oxide layer 223 is 0.1 nm to 2 nm.

[0232] For example, the thickness of oxide layer 223 is 0.1 nm, 0.2 nm, 0.4 nm, 0.5 nm, 1 nm, 1.5 nm or 2 nm, etc.

[0233] The oxide layer 223 can be designed to be thinner, thereby improving the tunneling effect of the oxide layer 223.

[0234] The thickness of the tunneling layer 221 and the thickness of the oxide layer 223 are set within a suitable range, such as 0.1 nm to 4 nm for the tunneling layer 221 and 0.1 nm to 4 nm for the oxide layer 223. The tunneling layer 221 and the oxide layer 223 can work together to passivate the battery and improve the tunneling effect of the tunneling layer 221 and the oxide layer 223, thereby enhancing the passivation performance and carrier transport of the back contact battery, and thus improving the electrical performance of the back contact battery, such as open circuit voltage and fill factor.

[0235] In some embodiments, the thickness of the tunneling layer 221 is greater than the thickness of the oxide layer 223.

[0236] On the one hand, the larger thickness of the tunneling layer 221 is beneficial to improving the passivation performance of the tunneling layer 221; on the other hand, when the first dopant diffuses through the tunneling layer 221 to the first doped layer 231, the smaller thickness of the oxide layer 223 is beneficial to the diffusion of the first dopant through the oxide layer 223 to the third doped layer 233.

[0237] In some embodiments, the density of the tunneling layer 221 is less than that of the oxide layer 223.

[0238] It is understandable that the porosity of the tunneling layer 221 is greater than that of the oxide layer 223.

[0239] It is possible that the tunneling layer 221 includes a porous structure, for example, the material of the tunneling layer 221 includes porous silicon oxide, and the material of the oxide layer 223 is silicon oxide, so that the density of the tunneling layer 221 is less than the density of the oxide layer 223.

[0240] For example, the density of the tunneling layer 221 is 30%-50%, and the density of the oxide layer 223 is 40%-70%.

[0241] The thickness of the tunneling layer 221 can be measured using X-ray reflectance (XRR) combined with fitting software (such as X-RayCalc or GenX). Alternatively, the fitted value of the refractive index of the tunneling layer 221 can be obtained using XRR combined with fitting software. Then, the density of the tunneling layer 221 can be calculated based on the fitted value n of the refractive index and the theoretical value n0 of the refractive index of the tunneling layer 221. The density of the tunneling layer 221 is the percentage of (1-n) to (1-n0). When the material of the tunneling layer 221 is silicon dioxide, the theoretical value of its refractive index is 1.4584 g / cm³. 3 The fitted value n of the refractive index of tunnel layer 221 can be obtained by performing a finite number of measurements and fittings, and then taking the average value.

[0242] Similarly, the density of oxide layer 223 can be detected by X-ray reflectance method (XRR) combined with fitting software, thereby obtaining the relationship between the density of tunneling layer 221 and the density of oxide layer 223.

[0243] The porosity between the tunneling layer 221 and the oxide layer 223 can also be detected by scanning electron microscopy combined with image analysis, thereby obtaining the density between the tunneling layer 221 and the oxide layer 223.

[0244] On the one hand, the lower density of the tunneling layer 221 facilitates the diffusion of the first dopant element through the tunneling layer 221 to the first doped layer 231 and the third doped layer 233. On the other hand, the higher density of the oxide layer 223 is beneficial for improving the passivation effect of the oxide layer 223.

[0245] In some embodiments, the thickness of the first doped layer 231 is 20 nm to 120 nm.

[0246] For example, the thickness of the first doped layer 231 is 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm or 120nm, etc.

[0247] In some embodiments, the thickness of the third doped layer 233 is 20 nm to 120 nm.

[0248] For example, the thickness of the third doped layer 233 is 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm or 120nm, etc.

[0249] Setting the thickness of the first doped layer 231 and the thickness of the third doped layer 233 within a suitable range, such as setting the thickness of the first doped layer 231 to 20nm-120nm and the thickness of the third doped layer 233 to 20nm-120nm, is beneficial for the incorporation of the second doping element into the first doped layer 231 and the third doped layer 233, which is beneficial for increasing the doping concentration of the first doped layer 231 and the third doped layer 233, and thus beneficial for improving the electrical performance of the back contact battery.

[0250] In some embodiments, the doping concentration of the first dopant element in the tunneling layer 221 is greater than the doping concentration of the first dopant element in the first doped layer 231. The average doping concentration of the first dopant element in the first doped layer 231 is greater than the average doping concentration of the first dopant element in the oxide layer 223. The doping concentration of the first dopant element in the oxide layer 223 is greater than the doping concentration of the first dopant element in the third doped layer 233.

[0251] The statement "the doping concentration of the first dopant element in oxide layer 223 is greater than the doping concentration of the first dopant element in third doping layer 233" can be: the doping concentration of the first dopant element in oxide layer 223 is greater than the doping concentration of the first dopant element in third doping layer 233; or the average doping concentration of the first dopant element in oxide layer 223 is greater than the doping concentration of the first dopant element in third doping layer 233; or the average doping concentration of the first dopant element in oxide layer 223 is greater than the average doping concentration of the first dopant element in third doping layer 233.

[0252] Along the direction from the tunneling layer 221 to the first doped layer 231, the doping concentration of the first doped element in the first doped layer 231 generally shows a trend of first decreasing and then increasing. The doping concentration of the first doped element in the third doped layer 233 generally shows a trend of first decreasing and then leveling off.

[0253] Since the doping concentration of the first dopant element in the tunneling layer 221 is relatively high, and the doping concentration of the first dopant element in the oxide layer 223 is greater than that in the third doped layer 233, it can be understood that the doping concentration of the first dopant element in the tunneling layer 221 and the oxide layer 223 each exhibits a peak value. This improves the passivation contact performance of the first region 2111. In some embodiments, the doping concentration of the first dopant element in the tunneling layer 221 is 2.4 × 10⁻⁶. 16 atom / cm 3 -5.4×10 18 atom / cm 3 .

[0254] For example, the doping concentration of the first dopant element in the tunneling layer 221 is 2.4 × 10⁻⁶. 16 atom / cm 3 5.0×10 16 atom / cm 3 4×10 17 atom / cm 3 Or 5.4×10 18 atom / cm 3 wait.

[0255] In some embodiments, the doping concentration of the first dopant element in the first doped layer 231 is 2 × 10⁻⁶. 15 atom / cm 3 -4.9×10 18 atom / cm 3 .

[0256] For example, the doping concentration of the first doped element in the first doped layer 231 is 2 × 10⁻⁶. 15 atom / cm 3 4×10 15 atom / cm 3 Or 4.9×10 18 atom / cm 3 wait.

[0257] In some embodiments, the doping concentration of the first dopant element in the oxide layer 223 is 2 × 10⁻⁶. 17 atom / cm 3 -5×10 17 atom / cm3 .

[0258] For example, the doping concentration of the first dopant element in oxide layer 223 is 2 × 10⁻⁶. 17 atom / cm 3 3×10 17 atom / cm 3 Or 5×10 17 atom / cm 3 wait.

[0259] In some embodiments, the doping concentration of the first dopant element in the third doped layer 233 is 1×10⁻⁶. 16 atom / cm 3 -4×10 17 atom / cm 3 .

[0260] For example, the doping concentration of the first dopant element in the third doped layer 233 is 1 × 10⁻⁶. 16 atom / cm 3 2×10 16 atom / cm 3 1×10 17 atom / cm 3 Or 4×10 17 atom / cm 3 wait.

[0261] Another embodiment of the back contact battery of this application also includes a first electrode 241, a second electrode 242, a first transparent conductive layer 251 and a second transparent conductive layer 252. The first transparent conductive layer 251 is disposed on the side of the third doped layer 233 away from the oxide layer 223. The first electrode 241 is disposed on the side of the first transparent conductive layer 251 away from the third doped layer 233. The second transparent conductive layer 252 is disposed on the side of the second doped layer 232 away from the barrier dielectric layer 222. The second electrode 242 is disposed on the side of the second transparent conductive layer 252 away from the second doped layer 232.

[0262] Another embodiment of the back contact battery in this application also includes a passivation layer 261 and an antireflection layer 262, which will not be described in detail here.

[0263] This application also provides a stacked battery, which includes the back contact battery of any of the above embodiments or the back contact battery prepared by the preparation method of the back contact battery of any of the above embodiments.

[0264] Specifically, such as Figure 8 As shown, the stacked battery includes a bottom battery 10, a composite layer 20, and a top battery 30 stacked sequentially along the first direction F1; wherein, the bottom battery 10 includes the aforementioned back contact battery.

[0265] It should be noted that the stacked battery provided in this application has the same technical effects as the back contact battery in this application, and the repetition will not be repeated.

[0266] The top cell 30 can be a perovskite solar cell. The band gap of a perovskite solar cell is wider than that of the bottom cell 10. Therefore, stacking a perovskite solar cell on top of the bottom cell 10 can give the tandem cell a wider spectral response range, thereby maximizing the utilization of solar energy and improving the efficiency of the tandem cell.

[0267] Perovskite solar cells have good radiation resistance, and with the continuous improvement of the photoelectric conversion efficiency of perovskite solar cells, tandem perovskite solar cells can also be well applied in space environments.

[0268] The composite layer 20 can be a transparent conductive oxide, which has good photoelectric properties, high photon transmittance, and high conductivity, thereby enabling the bottom cell 10 and the top cell 30 to maintain good ohmic contact.

[0269] In some embodiments, the stacked battery is a four-terminal stacked battery, that is, the stacked battery has four electrode terminals, the first electrode of the bottom battery 10 and the first electrode of the top battery 30 are respectively two electrode terminals of the stacked battery, and the second electrode of the bottom battery 10 and the second electrode of the top battery 30 are respectively two electrode terminals of the stacked battery.

[0270] In other embodiments, such as Figure 9 As shown, the stacked battery is a three-terminal stacked battery, that is, the stacked battery has three electrode terminals. The first and second electrodes of the bottom battery 10 serve as two of the electrode terminals of the stacked battery, and one electrode of the top battery 30 serves as the other electrode terminal of the stacked battery.

[0271] In some embodiments, the stacked battery is a two-terminal stacked battery, that is, the stacked battery has two electrode terminals, the first electrode of the bottom battery 10 and the first electrode of the top battery 30 are electrically connected to serve as one electrode terminal of the stacked battery, and the second electrode of the bottom battery 10 and the second electrode are electrically connected to serve as the other electrode terminal of the stacked battery.

[0272] This application also provides a photovoltaic module, which includes a back contact cell of any of the above embodiments, a back contact cell prepared by the preparation method of the back contact cell of any of the above embodiments, or the above-described stacked cell.

[0273] Specifically, such as Figure 10As shown, the photovoltaic module includes a cell string 101, an encapsulation layer 40, and a cover plate. The cell string 101 is formed by connecting the aforementioned back-contact cells or stacked cells. The encapsulation layer 40 covers the surface of the cell string 101. The cover plate is used to cover the surface of the encapsulation layer 40 away from the cell string 101.

[0274] The encapsulation layer 40 may include a first encapsulating adhesive layer and a second encapsulating adhesive layer. The cover plate may include a first cover plate 51 and a second cover plate 52. Along the first direction F1, a portion of the first encapsulating adhesive layer is disposed on one side of the battery string 101, and a portion of the second encapsulating adhesive layer is disposed on the other side of the battery string 101. The first cover plate 51 is disposed on the side of the first encapsulating adhesive layer away from the battery string 101, and the second cover plate 52 is disposed on the side of the second encapsulating adhesive layer away from the battery string 101.

[0275] The materials of the first and second encapsulating layers can be at least one of ethylene-vinyl acetate copolymer (EVA) encapsulating layer, polyolefin elastomer (POE) encapsulating layer, or polyvinyl butyral (PVB) encapsulating layer.

[0276] The first cover plate 51 and the second cover plate 52 can be glass covers, plastic covers, or other covers with light-transmitting functions.

[0277] The photovoltaic module may also include a frame. The first cover plate 51, the first encapsulating layer, the cell string 101, the second encapsulating layer and the second cover plate 52 are laminated to form a laminate (during the lamination process, the first encapsulating layer and the second encapsulating layer are bonded to each other to form an encapsulation layer 40). The frame is arranged around the laminate, that is, the frame is arranged around the laminate. In this way, the frame can be used to protect the edge of the laminate, improve the overall mechanical strength of the photovoltaic module, and facilitate the transportation and installation of the photovoltaic module.

[0278] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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, they should be considered to be within the scope of this specification.

[0279] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A back-contact battery, characterized in that, include: A substrate having a first surface; the first surface comprising alternating first and second regions; the substrate comprising at least a first dopant element; A tunnel layer is provided on the first region; A first doped layer is disposed on the side of the tunneling layer away from the substrate; the first doped layer includes a first doping element and a second doping element; the first doping element and the second doping element are elements of the same group; A barrier dielectric layer is provided at least in the second region; and The second doped layer is disposed on the side of the barrier dielectric layer away from the substrate, and includes a third doping element, wherein the third doping element has a different doping type than the first doping element.

2. The back contact battery according to claim 1, characterized in that, The thickness of the tunneling layer is less than the thickness of the barrier medium layer.

3. The back contact battery according to claim 1, characterized in that, The barrier dielectric layer includes at least one of an amorphous silicon layer, a microcrystalline silicon layer, and a nanocrystalline silicon layer.

4. The back contact battery according to claim 1, characterized in that, The barrier medium layer includes multiple sub-barrier layers; The sub-barrier layer is one of an amorphous silicon layer, a microcrystalline silicon layer, and a nanocrystalline silicon layer.

5. The back contact battery according to any one of claims 1-4, characterized in that, The tunneling layer includes the first doped element; the doping concentration of the first doped element in the tunneling layer is greater than the doping concentration of the first doped element in the first doped layer.

6. The back contact battery according to claim 5, characterized in that, The doping concentration of the first dopant element in the tunneling layer is 2 × 10⁻⁶. 16 atom / cm 3 -5×10 18 atom / cm 3 .

7. The back contact battery according to claim 5, characterized in that, The doping concentration of the first dopant element in the first doped layer is 2 × 10⁻⁶. 15 atom / cm 3 -4×10 18 atom / cm 3 .

8. The back contact battery according to any one of claims 1-4, characterized in that, The tunneling layer includes the first doping element; The doping concentration of the first dopant element in the tunneling layer is greater than the doping concentration of the first dopant element in the substrate.

9. The back contact battery according to any one of claims 1-4, characterized in that, The first doped layer includes a first portion and a second portion, which are disposed closer to the tunneling layer in the direction from the tunneling layer to the substrate, compared to the second portion. The doping concentration of the first dopant element in the first part is greater than the doping concentration of the first dopant element in the second part.

10. The back contact battery according to claim 9, characterized in that, The ratio of the average doping concentration of the first dopant element in the first part to the average doping concentration of the first dopant element in the second part is 5-15.

11. The back contact battery according to any one of claims 1-4, 6 or 7, characterized in that, The back contact battery also includes; An oxide layer, wherein the oxide layer is disposed on the side of the first doped layer away from the tunneling layer; and A third doped layer is disposed on the side of the oxide layer away from the first doped layer.

12. The back contact battery according to claim 11, characterized in that, The thickness of the tunneling layer is greater than the thickness of the oxide layer.

13. The back contact battery according to claim 11, characterized in that, The density of the tunneling layer is less than that of the oxide layer.

14. The back contact battery according to any one of claims 1-4, characterized in that, A portion of the barrier dielectric layer is disposed on the second region, and another portion of the barrier dielectric layer is disposed on the side of the first doped layer away from the tunneling layer.

15. The back contact battery according to claim 14, characterized in that, The substrate also has a second surface disposed opposite to the first surface; Compared to the first region, the second region is located closer to the second surface.

16. A method for preparing a back-contact battery, characterized in that, include: A substrate is provided: the substrate has a first surface; the first surface includes alternating first and second regions; the substrate includes at least a first dopant element; An initial tunneling layer is formed on the first surface; A first semiconductor layer comprising a second doped element is formed on at least a portion of the side of the initial tunneling layer away from the substrate; wherein the first doped element and the second doped element are elements of the same group; Removing the portions of the initial tunneling layer and the first semiconductor layer located in the second region to form a tunneling layer and a first doped layer; and A barrier dielectric layer is formed at least on the second region, and a second doped layer is formed on the side of the barrier dielectric layer away from the substrate; wherein the second doped layer includes a third doping element, the third doping element being of a different doping type than the first doping element.

17. The method for preparing a back contact battery according to claim 16, characterized in that, In the step of forming a first semiconductor layer comprising a second doped element on at least a portion of the side of the initial tunneling layer away from the substrate: the deposition temperature of the first semiconductor layer is in the range of 500°C-650°C; and / or The diffusion temperature of the second doped element diffuses into the first semiconductor layer ranges from 700℃ to 900℃.

18. The method for preparing a back contact battery according to claim 16, characterized in that, In the step of forming at least the barrier dielectric layer disposed on the second region, the deposition temperature of the barrier dielectric layer is less than 200°C; and / or In the step of forming the second doped layer on the side of the barrier dielectric layer away from the substrate, the deposition temperature of the second doped layer is less than 200°C.

19. A stacked battery, characterized in that, This includes the back contact battery as described in any one of claims 1-15 or the back contact battery prepared by the method described in any one of claims 16-18.

20. A photovoltaic module, characterized in that, This includes the back contact battery according to any one of claims 1-15, the back contact battery prepared by the method of preparing the back contact battery according to any one of claims 16-18, or the stacked battery according to claim 19.

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