Photovoltaic cell and preparation method thereof

Abstract

The invention provides a photovoltaic cell and a preparation method thereof. A photovoltaic cell includes a silicon substrate having opposing substrate front and back sides; the oxide layer and the first doping layer are sequentially located on the front face of the substrate, and the first doping layer comprises polycrystalline silicon; the first intrinsic layer and the second doping layer are located in the first area on the front face of the cell and are sequentially and closely located on the first doping layer, and the second doping layer comprises amorphous silicon or microcrystalline silicon; the second intrinsic layer, the third doped layer and the back transparent conductive film layer are sequentially located on the back of the substrate; the first metal electrodes are located on the front face of the cell, the second metal electrodes are located on the back face of the cell, each first metal electrode is located in a first area of the front face of the cell, no first metal electrode is arranged in a second area, and the second metal electrodes make contact with the back face transparent conductive film layer. According to the photovoltaic cell and the preparation method thereof, the metal contact and conductivity of the front surface of the cell can be optimized, and the cell efficiency is improved.

Description

Technical Field

[0001] The present application mainly relates to the field of photovoltaic technology, and in particular to a photovoltaic cell and a method for preparing the same. Background Art

[0002] The existing traditional heterojunction cells and TOPcon cells are both mainstream cell types in the photovoltaic field. Each has its own advantages over other cells, but they also have some shortcomings. For example, for heterojunction cells, the light absorption of the transparent conductive film layer on the front side is relatively serious. In addition, for crystalline silicon cells, it is usually necessary to prepare the electrode by burning through the dielectric film at high temperature and contacting with the crystalline silicon substrate. The metal contact area is seriously compounded and it is difficult to increase the opening voltage. Therefore, the structural improvement of the front functional layer and dielectric layer of the bifacial cell in this field still needs to be studied and improved. Summary of the invention

[0003] The technical problem to be solved by the present application is to provide a photovoltaic cell and a method for preparing the same, which can optimize the metal contact and conductive performance of the front side of the cell and improve the cell efficiency.

[0004] To solve the above technical problems, the present application provides a photovoltaic cell, comprising a front side of the cell and a back side of the cell, wherein the front side of the cell faces the light-facing side of the photovoltaic cell, and the front side of the cell comprises a first region and a second region arranged at intervals, and the photovoltaic cell comprises: a silicon substrate, having a substrate front side and a substrate back side opposite to each other, wherein the substrate front side is located on the side where the front side of the cell is located, and the substrate back side is located on the side where the back side of the cell is located; an oxide layer and a first doping layer, which are sequentially located on the front side of the substrate, wherein the first doping layer comprises polycrystalline silicon; a first intrinsic layer and a second doping layer, which are located on the front side of the cell in the first region and are sequentially located adjacent to the first doping layer, wherein the second doping layer comprises amorphous silicon or microcrystalline silicon, and the second doping layer and the first doping layer have the same first doping type; a second intrinsic layer, a third doping layer and a back transparent conductive film layer, which are sequentially located on the back side of the substrate; an anti-reflection dielectric film arranged on the front side of the cell; and a plurality of first metal electrodes located on the front side of the cell and a plurality of second metal electrodes located on the back side of the cell, wherein each of the first metal electrodes is located in the first region of the front side of the cell, the second region does not have the first metal electrode, and the second metal electrode is in contact with the back transparent conductive film layer.

[0005] Optionally, the anti-reflection dielectric film covers a plurality of the second regions on the front side of the cell, and covers a partial area of ​​each of the first regions.

[0006] Optionally, the anti-reflection dielectric film covers a plurality of the second regions on the front side of the cell and covers the entire area of ​​each of the first regions.

[0007] Optionally, the anti-reflection dielectric film wraps around each of the first metal electrodes in the first region in a circumferential direction.

[0008] Optionally, the anti-reflection dielectric film includes a single layer or a composite layer, the composite layer is a plurality of layers stacked together, and the single layer or the composite layer includes one or more materials selected from silicon oxide, silicon nitride, silicon oxynitride, and magnesium fluoride.

[0009] Optionally, the refractive index of the anti-reflection dielectric film gradually decreases in a direction approaching the front side of the battery.

[0010] Optionally, the first metal electrode contacts the second doping layer on the front side of the battery.

[0011] Optionally, the photovoltaic cell further comprises a front transparent conductive film layer located on the side where the front side of the cell is located, and at least a portion of the front transparent conductive film layer is located on the inner side of the anti-reflection dielectric film on the front side of the cell.

[0012] Optionally, when the anti-reflection dielectric film covers multiple second regions on the front side of the battery and covers a local area of ​​each first region, in the first region, the portion of the front transparent conductive film layer located in the local area is located between the second doped layer and the anti-reflection dielectric film.

[0013] Optionally, the first metal electrode is in contact with the front transparent conductive film layer on the front side of the battery.

[0014] Another aspect of the present application also provides a method for preparing a photovoltaic cell, wherein the photovoltaic cell comprises a front side of the cell and a back side of the cell, wherein the front side of the cell faces the light-facing side of the photovoltaic cell, and the front side of the cell comprises a first region and a second region that are spaced apart, and the preparation method comprises the following steps: providing a silicon substrate, wherein the silicon substrate has a front side of the substrate and a back side of the substrate that are opposite to each other, wherein the front side of the substrate is located on the side where the front side of the cell is located, and the back side of the substrate is located on the side where the back side of the cell is located; preparing an oxide layer and a first doped layer, wherein the oxide layer and the first doped layer are sequentially located on the front side of the substrate, and the first doped layer comprises polycrystalline silicon; preparing a first intrinsic layer and a second doped layer, wherein the first intrinsic layer and the second doped layer are disposed on the front side of the cell; The front side of the cell is located in the first region and is sequentially adjacent to the first doped layer, wherein the second doped layer comprises amorphous silicon or microcrystalline silicon, and the second doped layer and the first doped layer have the same first doping type; a second intrinsic layer, a third doped layer and a back transparent conductive film layer are prepared, and the second intrinsic layer, the third doped layer and the back transparent conductive film layer are sequentially located on the back side of the substrate; and a plurality of first metal electrodes located on the front side of the cell and a plurality of second metal electrodes located on the back side of the cell are prepared, wherein each of the first metal electrodes is located in the first region of the front side of the cell, the second region does not have the first metal electrode, and the second metal electrode is in contact with the back transparent conductive film layer.

[0015] Optionally, the preparation method also includes: arranging the oxide layer, the first doping layer, the first intrinsic layer and the second doping layer in sequence on the front side of the substrate; arranging a mask layer on the surface of the second doping layer by patterning, and removing the second doping layer and the first intrinsic layer in the area not covered by the mask layer by an alkaline solution; arranging the second intrinsic layer, the third doping layer and the back transparent conductive film layer in sequence on the back side of the substrate; preparing a plurality of the first metal electrodes and a plurality of the second metal electrodes, and making each of the first metal electrodes contact the second doping layer, and each of the second metal electrodes contact the back transparent conductive film layer.

[0016] Optionally, the preparation method also includes: arranging the oxide layer, the first doping layer, the first intrinsic layer and the second doping layer in sequence on the front side of the substrate; arranging a mask layer on the surface of the second doping layer by patterning, and removing the second doping layer and the first intrinsic layer in the area not covered by the mask layer by an alkaline solution; arranging the second intrinsic layer and the third doping layer in sequence on the back side of the substrate; preparing a front transparent conductive film layer on the side where the front side of the substrate is located, and preparing the back transparent conductive film layer on the side where the back side of the substrate is located; preparing a plurality of the first metal electrodes and a plurality of the second metal electrodes, and making each of the first metal electrodes contact the front transparent conductive film layer, and each of the second metal electrodes contact the back transparent conductive film layer.

[0017] Optionally, the preparation method also includes: arranging the oxide layer, the first doped layer, the first intrinsic layer and the second doped layer in sequence on the front side of the substrate; arranging the second intrinsic layer and the third doped layer in sequence on the back side of the substrate; preparing a front transparent conductive film layer on the side where the front side of the substrate is located, and preparing the back transparent conductive film layer on the side where the back side of the substrate is located; preparing a plurality of the first metal electrodes and a plurality of the second metal electrodes, and making each of the first metal electrodes contact with the front transparent conductive film layer, and each of the second metal electrodes contact with the back transparent conductive film layer; removing the front transparent conductive film layer in the second area by an acid solution, and removing the second doped layer and the first intrinsic layer in the second area by an alkaline solution.

[0018] Optionally, the preparation method further comprises preparing an anti-reflection dielectric film in a plurality of the second regions on the front side of the battery and a plurality of partial or complete first regions after preparing a plurality of the first metal electrodes and a plurality of the second metal electrodes.

[0019] Compared with the prior art, the present application has the following advantages: The present application arranges a superposition combination of polycrystalline silicon and amorphous silicon / microcrystalline silicon on the front of the battery, which can reduce the metal contact area recombination, ensure the passivation effect, and improve the battery efficiency. In some preferred embodiments, by arranging a plurality of superposition combinations of dielectric films and conductive films in different areas on the front of the battery, the parasitic absorption of light can be further reduced, the metal recombination can be reduced, the passivation anti-reflection effect can be optimized, and the metal contact and conductive performance can be optimized, thereby further improving the battery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0021] Figure 1 is a schematic structural diagram of a photovoltaic cell according to an embodiment of the present application;

[0022] Figure 2 is a schematic structural diagram of a photovoltaic cell according to another embodiment of the present application;

[0023] Figure 3 is a schematic structural diagram of a photovoltaic cell according to another embodiment of the present application;

[0024] Figure 4 is a schematic structural diagram of a photovoltaic cell according to another embodiment of the present application;

[0025] Figure 5 is a schematic structural diagram of a photovoltaic cell according to another embodiment of the present application;

[0026] Figure 6 is a schematic structural diagram of a photovoltaic cell according to another embodiment of the present application; and

[0027] Figure 7 It is a schematic diagram of a process for preparing a photovoltaic cell according to an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0029] As shown in this application and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0030] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0031] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0032] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0033] In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and cannot be understood as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some terms mentioned in the specification of this application may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description of this article. In addition, it is required to understand this application not only by the actual terms used, but also by the meaning implied by each term.

[0034] It should be understood that when a component is referred to as being "on another component," "connected to another component," "coupled to another component," or "contacting another component," it may be directly on, connected to, coupled to, or contacting the other component, or there may be intervening components. In contrast, when a component is referred to as being "directly on another component," "directly connected to," "directly coupled to," or "directly contacting" another component, there are no intervening components. Similarly, when a first component is referred to as being "electrically in contact with" or "electrically coupled to" a second component, there is an electrical path between the first component and the second component that allows current to flow. The electrical path may include capacitors, coupled inductors, and / or other components that allow current to flow, even without direct contact between conductive components.

[0035] An embodiment of the present application refers to Figure 1 A photovoltaic cell 10 is proposed, which can optimize the metal contact and conductive performance of the front side of the cell and improve the cell efficiency.

[0036] according to Figure 1 The photovoltaic cell 10 includes a cell front side 101 and a cell back side 102, the cell front side 101 faces the light-facing side of the photovoltaic cell 10, and the cell front side 101 includes a first region 1011 and a second region 1012 that are spaced apart. More specifically, the photovoltaic cell 10 includes a silicon substrate 100, the silicon substrate 100 has a substrate front side 103 and a substrate back side 104 that are opposite to each other, the substrate front side 103 is located on the side where the cell front side 101 is located, and the substrate back side 104 is located on the side where the cell back side 102 is located.

[0037] Continue to refer to Figure 1The photovoltaic cell 10 further includes an oxide layer 11 and a first doping layer 12, which are sequentially located on the front side 103 of the substrate. In this embodiment, the first doping layer 12 includes polycrystalline silicon. Further, on the side of the front side 101 of the cell, there is also a first intrinsic layer 13 and a second doping layer 14, which are located in the first region 1011 on the front side 101 of the cell and are sequentially located adjacent to the first doping layer 12, wherein the second doping layer 14 includes amorphous silicon or microcrystalline silicon, and the second doping layer 14 and the first doping layer 12 have the same first doping type.

[0038] On this basis, the back side 102 of the battery further has a second intrinsic layer 15 , a third doping layer 16 and a back transparent conductive film layer 172 , which are sequentially located on the back side 104 of the substrate. Figure 1 Also shown are a plurality of first metal electrodes 181 located on the front side 101 of the battery and a plurality of second metal electrodes 182 located on the back side 102 of the battery. Figure 1 It is clearly shown that each first metal electrode 181 is located in the first region 1011 of the front side 101 of the battery, and there is no first metal electrode 101 in the second region 1012. In this embodiment, the first metal electrode 181 contacts the second doping layer 14 on the side of the front side 101 of the battery; and the second metal electrode 182 contacts the back transparent conductive film layer 172 on the side where the back side 102 of the battery is located.

[0039] This application includes Figure 1 In the multiple embodiments, the silicon substrate 100 is preferably implemented as N-type doped crystalline silicon. The oxide layer 11 can be silicon oxide, which has a tunnel passivation effect. The first doped layer 12 is specifically phosphorus-doped polycrystalline silicon, and the second doped layer 14 is phosphorus-doped amorphous silicon or microcrystalline silicon. In contrast, the third doped layer 16 on the back side 102 of the battery is implemented as boron-doped amorphous silicon or microcrystalline silicon. It can be understood that the above-mentioned doping type setting method is only a preferred embodiment of the present application, but the present application is not limited thereto.

[0040] Further, in the present embodiment, preferably, the photovoltaic cell 10 further includes an anti-reflection dielectric film 19, which is located at the outermost layer of the cell front 101. It can be seen that in the present embodiment, the anti-reflection dielectric film 19 covers a plurality of second regions 1012 on the cell front 101, and covers a local region a of each first region 1011. Exemplarily, the anti-reflection dielectric film 19 includes a single layer or a composite layer, the composite layer is a plurality of layers superimposed, and the single layer or the composite layer includes one or more materials selected from silicon oxide, silicon nitride, silicon oxynitride, and magnesium fluoride.

[0041] On this basis, Figure 2 to Figure 6 They are shown based on Figure 1 Some preferred variant embodiments of the photovoltaic cell 10, which are shown in the drawings Figure 1The same components in the embodiments are marked with the same reference numerals, and the differences are mainly described in detail below.

[0042] First refer to Figure 2 , which shows a schematic diagram of the structure of the photovoltaic cell 20. Figure 1 The difference of the embodiment shown is that the photovoltaic cell 20 has an anti-reflection dielectric film 29. Figure 1 The anti-reflection dielectric film 19 shown in the figure covers a plurality of second regions 1012 and covers the entire region of each first region 1011. More preferably in this embodiment, the anti-reflection dielectric film 29 wraps around each first metal electrode 181 in the first region 1011 in the circumferential direction. Figure 2 In the multiple embodiments of the invention, an implementation method of wrapping the first metal electrode with an anti-reflection dielectric film is shown. Such a first metal electrode is mainly considered to correspond to the position of the fine grid lines in the photovoltaic cell module preparation scenario. Generally, during the module preparation process, only the welding strip and the main grid lines need to be welded to each other without exposing the fine grid lines. In such an implementation scenario, wrapping the first metal electrode with an anti-reflection dielectric film in the circumferential direction can reduce the difficulty of module preparation and facilitate the subsequent industrial application of photovoltaic cells. The embodiments of wrapping the first metal electrode with an anti-reflection dielectric film described below can be understood in the same way.

[0043] On this basis, Figure 3 to Figure 6 The embodiments of further adding a transparent conductive film layer to the front side 101 of the battery to optimize the front side performance of the battery are shown respectively. Figure 3 , which shows a schematic diagram of the structure of the photovoltaic cell 30. The photovoltaic cell 30 is based on Figure 1 Improvements of the embodiment shown, compared Figure 1 and Figure 3 , the anti-reflection dielectric film 39 is located at the outermost layer of the front surface 101 of the cell, and the anti-reflection dielectric film 39 covers a plurality of second regions 1012 on the front surface 101 of the cell, and covers a local region a of each first region 1011. On this basis, the photovoltaic cell 30 further includes a front transparent conductive film layer 371, which is located on the side where the front surface 101 of the cell is located. Figure 3, a part of the front transparent conductive film layer 371 is located inside the anti-reflection dielectric film 19 at the front side 101 of the battery. Specifically, in the first region 1011, in the local region a, the front transparent conductive film layer 371 is located between the second doping layer 14 and the anti-reflection dielectric film 39, and in the region outside the local region a in the first region 1011, a part of the front transparent conductive film layer 371 is located at the outermost side of the front side 101 of the battery; and in the second region 1012, the front transparent conductive film layer 371 is completely located inside the anti-reflection dielectric film 19. In this embodiment, the first metal electrode 181 contacts the front transparent conductive film layer 371 at the side of the front side 101 of the battery.

[0044] In different embodiments of the present application, the front transparent conductive film layer and / or the back transparent conductive film layer may be composed of a transparent conductive oxide, wherein the transparent conductive oxide includes tin-doped indium oxide, tungsten-doped indium oxide and / or cesium-doped indium oxide, or includes ZnO or InO or SnO doped with one or more of Ga, Sn, Mo, Ce, F, W, and Al.

[0045] Further references Figure 4 The photovoltaic cell 40 shown, Figure 4 is based on Figure 3 A further variation of Figure 3 The difference of the embodiment shown is that the photovoltaic cell 40 has an anti-reflection dielectric film 49. Figure 4 The anti-reflection dielectric film 39 shown covers a plurality of second regions 1012 and covers the entire area of ​​each first region 1011. More preferably in this embodiment, the anti-reflection dielectric film 49 wraps around each first metal electrode 181 in the first region 1011 in the circumferential direction.

[0046] Further references Figure 5 The photovoltaic cell 50 shown, Figure 5 is based on Figure 3 A further variation of Figure 3 The difference of the embodiment shown is that although the photovoltaic cell 50 also has a front transparent conductive film layer 571 disposed on the front side 101 of the cell, the front transparent conductive film layer 571 is located in the first area 1011, and the anti-reflection dielectric film 59 covers a plurality of second areas 1012 on the front side 101 of the cell and covers a local area a of each first area 1011. On this basis, Figure 6 Shown based on Figure 5 A further variation of Figure 6, the front transparent conductive film layer 671 is located in the first region 1011, but the anti-reflection dielectric film 69 covers the plurality of second regions 1012 and covers the entire region of each first region 1011. More preferably in this embodiment, the anti-reflection dielectric film 69 wraps around each first metal electrode 181 in the first region 1011 in the circumferential direction.

[0047] It should be noted that compared with Figure 1 and Figure 2 The embodiment shown, Figure 3 to Figure 6 The embodiment shown can be understood as being based on Figure 1 , Figure 2 Further preferred variations of the illustrated embodiments. In these embodiments, the front side 101 of the battery is partially or frontally provided with a front transparent conductive film layer and an anti-reflection dielectric film in a superimposed combination, which performs better than conventional batteries. First, according to the foregoing description, the anti-reflection dielectric film may include a single layer or a composite layer of multiple single layers superimposed, and whether it is a single layer or a composite layer, the anti-reflection dielectric film may be made of one or more materials selected from silicon oxide, silicon nitride, silicon oxynitride, and magnesium fluoride. It should be noted that even if a single material, such as silicon nitride, is used, silicon nitride layers with different refractive indices can be formed by controlling different ratios of silane and ammonia. Therefore, even if the anti-reflection dielectric film is made of a single silicon nitride material, it can be considered to be implemented as a composite layer of multiple superimposed layers, and at this time, these multiple layers include silicon nitride layers with different refractive indices.

[0048] It is particularly important to note that in this application Figure 1 to Figure 6 In the multiple embodiments, preferably, the refractive index of the anti-reflection dielectric film gradually decreases as it approaches the front surface 101 of the battery, that is, the refractive index of the single layer close to the front surface 101 of the battery is the lowest. This setting can be beneficial to the increase of current and further improve efficiency. Under this premise, Figure 3 , Figure 4 The embodiment shows that in the second region 1012, the front transparent conductive film layers 371 and 471 are located immediately inside the anti-reflection dielectric film. For such an embodiment, it can be considered that the single layer with the highest refractive index located at the innermost side of the composite layer farthest from the front face 101 of the battery (when the anti-reflection dielectric film is implemented as a composite layer structure) or the partial area of ​​the anti-reflection dielectric film farthest from the front face 101 of the battery (when the anti-reflection dielectric film is implemented as a single layer structure) in the original composite layer is directly replaced with the front transparent conductive film layers 371 and 471. Through such a special structural setting, better metal contact and lateral conductivity of the front face 101 of the battery can be provided under the premise of ensuring that the optical loss is effectively controlled.

[0049] On the other hand, for Figure 5 , Figure 6In the embodiment shown, only the front transparent conductive film layers 571 and 671 of the first region 1011 are retained, which can improve the front performance of the battery from another aspect. Figure 1 , Figure 2 Compared with the embodiment shown, although Figure 1 , Figure 2 The first doped layer implemented as polysilicon in the illustrated embodiment can improve the performance of the front side 101 of the battery. However, considering that the first region 101 needs to achieve metal contact with the first metal electrode 181, the front transparent conductive film layers 571 and 671 are provided and the first metal electrode 181 is in contact with the first metal electrode 181. Compared with the method of preparing the electrode by burning through the dielectric film of materials such as silicon nitride, these embodiments can directly use low-temperature slurry to prepare the first metal electrode 181, which has less metal composite and is conducive to opening voltage, thereby optimizing efficiency. Figure 3 , Figure 4 The embodiment shown also has the same technical effect as described above with respect to the preparation method of the first metal electrode 181 in the first region 1011 .

[0050] Another aspect of the present application also refers to Figure 7 A method for preparing a photovoltaic cell is proposed. The photovoltaic cell comprises a front side of the cell and a back side of the cell, the front side of the cell faces the light-facing side of the photovoltaic cell, and the front side of the cell comprises a first region and a second region arranged at intervals. Figure 7 Flowcharts are used to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed precisely in order. Instead, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0051] The preparation method 70 includes the following steps. Step 71 is to provide a silicon substrate, the silicon substrate has a substrate front side and a substrate back side opposite to each other, the substrate front side is located on the side where the battery front side is located, and the substrate back side is located on the side where the battery back side is located. Step 72 is to prepare an oxide layer and a first doping layer, the oxide layer and the first doping layer are sequentially located on the substrate front side, and the first doping layer includes polycrystalline silicon. Step 73 is to prepare a first intrinsic layer and a second doping layer, the first intrinsic layer and the second doping layer are located in the first region on the front side of the battery, and are sequentially located adjacent to the first doping layer, wherein the second doping layer includes amorphous silicon or microcrystalline silicon, and the second doping layer has the same first doping type as the first doping layer. Step 74 is to prepare a second intrinsic layer, a third doping layer and a back transparent conductive film layer, the second intrinsic layer, the third doping layer and the back transparent conductive film layer are sequentially located on the back side of the substrate. Step 75 is to prepare a plurality of first metal electrodes located on the front side of the battery and a plurality of second metal electrodes located on the back side of the battery, wherein each first metal electrode is located in the first region on the front side of the battery, there is no first metal electrode in the second region, and the second metal electrode is in contact with the back transparent conductive film layer.

[0052] For example, Figure 7 The manufacturing method 70 shown can be used to manufacture the photovoltaic cell provided in any embodiment of the present application, for example, by Figure 1 to Figure 6 Proposed photovoltaic cells 10 to 60. Taking photovoltaic cells 10 to 60 as an example, other details of the preparation method 70 and some specific sight lines are further described below.

[0053] First, when the preparation method 70 is used to prepare Figure 1 The photovoltaic cell 10 shown first sequentially arranges an oxide layer 11, a first doping layer 12, a first intrinsic layer 13 and a second doping layer 14 on the front side 103 of the substrate. Further, a mask layer is graphically arranged on the surface of the second doping layer 14, and the second doping layer 14 and the first intrinsic layer 13 in the area not covered by the mask layer are removed by an alkaline solution. On this basis, a second intrinsic layer 15, a third doping layer 16 and a back transparent conductive film layer 172 are sequentially arranged on the back side 104 of the substrate. Further, a plurality of first metal electrodes 181 and a plurality of second metal electrodes 182 are prepared, and each first metal electrode 181 is in contact with the second doping layer 14, and each second metal electrode 182 is in contact with the back transparent conductive film layer 172. Finally, an anti-reflection dielectric film 19 is prepared in the plurality of second regions 1012 on the front side 101 of the cell, and in the local area a of the plurality of first regions 1011.

[0054] On this basis, Figure 2 Compared to Figure 1 The only difference is the laying position of the anti-reflection dielectric film 29. Figure 1Compared with the preparation process of , there are only differences in the following steps. Figure 2 The photovoltaic cell 20 shown is prepared, after preparing a plurality of first metal electrodes 181 and a plurality of second metal electrodes 182 , and then preparing an anti-reflection dielectric film 29 in a plurality of second regions 1012 on the front side 101 of the cell and in a plurality of complete first regions 1011 .

[0055] On this basis, Figure 3 The photovoltaic cell 30 shown can be prepared by the following preparation method. First, an oxide layer 11, a first doping layer 12, a first intrinsic layer 13 and a second doping layer 14 are sequentially arranged on the front side 103 of the substrate. Further, a mask layer is patterned on the surface of the second doping layer 14, and the second doping layer 14 and the first intrinsic layer 13 in the area not covered by the mask layer are removed by an alkaline solution. A second intrinsic layer 15 and a third doping layer 16 are sequentially arranged on the back side 104 of the substrate. A front transparent conductive film layer 371 is prepared on the side where the front side 103 of the substrate is located, and a back transparent conductive film layer 172 is prepared on the side where the back side 104 of the substrate is located. On this basis, a plurality of first metal electrodes 181 and a plurality of second metal electrodes 182 are prepared, and each first metal electrode 181 is in contact with the front transparent conductive film layer 371, and each second metal electrode 182 is in contact with the back transparent conductive film layer 172. Finally, an anti-reflection dielectric film 39 is prepared in the plurality of second regions 1012 of the front side 101 of the battery, and in the local area a of the plurality of first regions 1011.

[0056] On this basis, Figure 4 Compared to Figure 3 The only difference is the laying position of the anti-reflection dielectric film 49. Figure 3 Compared with the preparation process of , there are only differences in the following steps. Figure 3 The photovoltaic cell 30 shown is prepared, after preparing a plurality of first metal electrodes 181 and a plurality of second metal electrodes 182 , an anti-reflection dielectric film 39 is prepared in a plurality of second regions 1012 on the front side 101 of the cell and in a plurality of complete first regions 1011 .

[0057] Furthermore, Figure 5The photovoltaic cell 50 shown can be prepared in the following manner. First, an oxide layer 11, a first doping layer 12, a first intrinsic layer 13, and a second doping layer 14 are sequentially arranged on the front side 103 of the substrate. A second intrinsic layer 15 and a third doping layer 16 are sequentially arranged on the back side 104 of the substrate. Then, a front transparent conductive film layer 571 is prepared on the side where the front side 103 of the substrate is located, and a back transparent conductive film layer 172 is prepared on the side where the back side 104 of the substrate is located. On this basis, a plurality of first metal electrodes 181 and a plurality of second metal electrodes 182 are prepared, and each first metal electrode 181 is in contact with the front transparent conductive film layer 571, and each second metal electrode 182 is in contact with the back transparent conductive film layer 172. The front transparent conductive film layer 571 in the second region 1012 is further removed by an acid solution, and the second doping layer 14 and the first intrinsic layer 13 in the second region 1012 are removed by an alkaline solution. Finally, an anti-reflection dielectric film 59 is prepared in the plurality of second regions 1012 of the battery front side 101 and in the local region a of the plurality of first regions 1011 .

[0058] On this basis, Figure 6 Compared to Figure 5 The only difference is the laying position of the anti-reflection dielectric film 69. Figure 5 Compared with the preparation process of , there are only differences in the following steps. Figure 6 The photovoltaic cell 60 shown is prepared, after preparing a plurality of first metal electrodes 181 and a plurality of second metal electrodes 182 , and then preparing an anti-reflection dielectric film 69 in a plurality of second regions 1012 on the front side 101 of the cell and in a plurality of complete first regions 1011 .

[0059] The basic concepts have been described above. Obviously, for those skilled in the art, the above application disclosure is only an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0060] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0061] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more application embodiments, in the above description of the embodiments of this application, multiple features are sometimes merged into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0062] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0063] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the claims of the present application.

Claims

1. A photovoltaic cell, characterized in that: The photovoltaic cell comprises a front side of the cell and a back side of the cell, wherein the front side of the cell faces the light-facing side of the photovoltaic cell, and the front side of the cell comprises a first area and a second area which are spaced apart from each other, and the photovoltaic cell comprises: A silicon substrate having a substrate front side and a substrate back side opposite to each other, wherein the substrate front side is located on the side where the battery front side is located, and the substrate back side is located on the side where the battery back side is located; An oxide layer and a first doping layer are sequentially disposed on the front surface of the substrate, wherein the first doping layer comprises polysilicon; A first intrinsic layer and a second doped layer, located in the first region on the front side of the battery and adjacent to the first doped layer in sequence, wherein the second doped layer comprises amorphous silicon or microcrystalline silicon, and the second doped layer and the first doped layer have the same first doping type; A second intrinsic layer, a third doped layer and a back transparent conductive film layer are sequentially located on the back side of the substrate; An anti-reflection dielectric film disposed on the front side of the cell; and A plurality of first metal electrodes are located on the front side of the battery and a plurality of second metal electrodes are located on the back side of the battery, wherein each of the first metal electrodes is located in the first region on the front side of the battery, the second region does not have the first metal electrode, and the second metal electrodes are in contact with the back transparent conductive film layer.

2. The photovoltaic cell according to claim 1, characterized in that The anti-reflection dielectric film covers a plurality of the second regions on the front side of the cell and covers a partial area of ​​each of the first regions.

3. The photovoltaic cell according to claim 1, characterized in that The anti-reflection dielectric film covers a plurality of the second regions on the front side of the cell and covers the entire area of ​​each of the first regions.

4. The photovoltaic cell according to claim 3, characterized in that: The anti-reflection dielectric film circumferentially wraps around each of the first metal electrodes in the first region.

5. The photovoltaic cell according to claim 1, characterized in that: The anti-reflection dielectric film includes a single layer or a composite layer, the composite layer is a plurality of layers stacked together, and the single layer or the composite layer includes one or more materials selected from silicon oxide, silicon nitride, silicon oxynitride, and magnesium fluoride.

6. The photovoltaic cell according to claim 5, characterized in that: The refractive index of the anti-reflection dielectric film gradually decreases in a direction approaching the front side of the battery.

7. The photovoltaic cell according to any one of claims 1 to 6, characterized in that: The first metal electrode contacts the second doping layer at the front side of the battery.

8. The photovoltaic cell according to any one of claims 1 to 6, characterized in that: It also includes a front transparent conductive film layer, which is located on the side where the front of the battery is located, and at least a part of the front transparent conductive film layer is located on the inner side of the anti-reflection dielectric film on the front of the battery.

9. The photovoltaic cell according to claim 8, characterized in that: When the anti-reflection dielectric film covers multiple second areas on the front side of the battery and covers a local area of ​​each first area, in the first area, the part of the front transparent conductive film layer located in the local area is located between the second doped layer and the anti-reflection dielectric film.

10. The photovoltaic cell according to claim 8, characterized in that The first metal electrode is in contact with the front transparent conductive film layer at the front side of the battery.

11. A method for preparing a photovoltaic cell, characterized in that: The photovoltaic cell comprises a front side of the cell and a back side of the cell, the front side of the cell faces the light-facing side of the photovoltaic cell, and the front side of the cell comprises a first region and a second region that are spaced apart, and the preparation method comprises the following steps: Providing a silicon substrate, the silicon substrate having a substrate front side and a substrate back side opposite to each other, the substrate front side is located on the side where the front side of the battery is located, and the substrate back side is located on the side where the back side of the battery is located; preparing an oxide layer and a first doping layer, wherein the oxide layer and the first doping layer are sequentially located on the front side of the substrate, and the first doping layer comprises polycrystalline silicon; Prepare a first intrinsic layer and a second doped layer, wherein the first intrinsic layer and the second doped layer are located in the first region on the front side of the battery and are sequentially adjacent to the first doped layer, wherein the second doped layer comprises amorphous silicon or microcrystalline silicon, and the second doped layer and the first doped layer have the same first doping type; preparing a second intrinsic layer, a third doped layer and a back transparent conductive film layer, wherein the second intrinsic layer, the third doped layer and the back transparent conductive film layer are sequentially located on the back side of the substrate; and A plurality of first metal electrodes located on the front side of the battery and a plurality of second metal electrodes located on the back side of the battery are prepared, wherein each of the first metal electrodes is located in the first region on the front side of the battery, the second region does not have the first metal electrode, and the second metal electrodes are in contact with the transparent conductive film layer on the back side.

12. The preparation method according to claim 11, characterized in that: Also includes: sequentially disposing the oxide layer, the first doping layer, the first intrinsic layer and the second doping layer on the front side of the substrate; A mask layer is provided on the surface of the second doped layer by patterning, and the second doped layer and the first intrinsic layer in the area not covered by the mask layer are removed by an alkaline solution; The second intrinsic layer, the third doped layer and the back transparent conductive film layer are sequentially arranged on the back side of the substrate; A plurality of the first metal electrodes and a plurality of the second metal electrodes are prepared, and each of the first metal electrodes is in contact with the second doping layer, and each of the second metal electrodes is in contact with the back transparent conductive film layer.

13. The preparation method according to claim 11, characterized in that: Also includes: sequentially disposing the oxide layer, the first doping layer, the first intrinsic layer and the second doping layer on the front side of the substrate; A mask layer is provided on the surface of the second doped layer by patterning, and the second doped layer and the first intrinsic layer in the area not covered by the mask layer are removed by an alkaline solution; sequentially disposing the second intrinsic layer and the third doped layer on the back side of the substrate; Prepare a front transparent conductive film layer on the side where the front side of the substrate is located, and prepare the back transparent conductive film layer on the side where the back side of the substrate is located; A plurality of the first metal electrodes and a plurality of the second metal electrodes are prepared, and each of the first metal electrodes is in contact with the front transparent conductive film layer, and each of the second metal electrodes is in contact with the back transparent conductive film layer.

14. The preparation method according to claim 11, characterized in that: Also includes: sequentially disposing the oxide layer, the first doping layer, the first intrinsic layer and the second doping layer on the front side of the substrate; sequentially disposing the second intrinsic layer and the third doped layer on the back side of the substrate; Prepare a front transparent conductive film layer on the side where the front side of the substrate is located, and prepare the back transparent conductive film layer on the side where the back side of the substrate is located; Prepare a plurality of the first metal electrodes and a plurality of the second metal electrodes, and make each of the first metal electrodes contact the front transparent conductive film layer, and each of the second metal electrodes contact the back transparent conductive film layer; The front transparent conductive film layer in the second region is removed by an acid solution, and the second doped layer and the first intrinsic layer in the second region are removed by an alkaline solution.

15. The preparation method according to any one of claims 11 to 14, characterized in that: The method further comprises preparing an anti-reflection dielectric film in a plurality of the second regions on the front side of the battery and in a plurality of partial or complete first regions after preparing a plurality of the first metal electrodes and a plurality of the second metal electrodes.

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