Back contact cell, cell assembly and photovoltaic system

Abstract

The invention relates to the technical field of solar cells, and provides a back contact cell, a cell assembly and a photovoltaic system, a first passivation contact structure of the back contact cell is arranged on a first region, and the first passivation contact structure can comprise a first passivation layer and a first doping layer, the included angle between the side wall face of the first passivation contact structure and the surface of the second area is larger than or equal to 60 degrees and smaller than 90 degrees, and the second passivation contact structure is arranged on the second area and comprises a second passivation layer and a second doping layer. The second passivation layer is stacked on the second region and extends from the second region to the sidewall surface and at least a partial region of the back surface of the first passivation contact structure, and the second doping layer is disposed on the second passivation layer. Therefore, the shape-preserving deposition of the second passivation layer on the side wall surface can be optimized, and the passivation effect on the side wall surface of the first passivation contact structure is improved, so that the performance of the back contact battery is improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a back-contact cell, a cell assembly and a photovoltaic system. Background Art

[0002] At present, among solar cells, a back contact cell is a cell in which both the emitter and base contact electrodes are placed on the back of the cell, and the front of the cell is not blocked by any metal electrode, thereby effectively increasing the short-circuit current of the cell. In order to improve the efficiency of the back contact cell, one of the doped layers of the back contact cell can be set to a polycrystalline silicon layer, and the other doped layer can be set to an amorphous silicon layer or a microcrystalline silicon layer, thereby forming a hybrid back contact cell, that is, a hybrid back contact cell is formed by using two different passivation contact structures of opposite types.

[0003] In the back contact battery of the related art, during the manufacturing process, there is a stacked structure in which a passivation contact structure extends and covers another passivation contact structure. For example, a stacked structure is formed by extending a passivation contact structure in a P-type region to cover a passivation contact structure in an N-type region. In this case, during the deposition process, the thickness of the passivation layer on the side of the passivation contact structure in the N-type region in the passivation contact structure in the P-type region is too thin, or even some areas do not have a passivation layer, which will result in poor passivation effect on the side of the passivation contact structure in the N-type region, or even cause some areas to be unable to be passivated, and the overall passivation effect is reduced, affecting the performance of the back contact battery, and vice versa. Therefore, the performance of the back contact battery in the prior art needs to be improved. Summary of the invention

[0004] The present application provides a back-contact cell, a cell assembly and a photovoltaic system.

[0005] The present application is implemented in this way. The back contact battery of the embodiment of the present application includes:

[0006] A silicon substrate having a first surface and a second surface opposite to each other, wherein the second surface includes adjacent first and second regions;

[0007] a first passivation contact structure disposed on the first region, the first passivation contact structure comprising a first passivation layer and a first doping layer sequentially stacked on the first region, the first passivation contact structure having a back surface away from the second surface and a side wall surface adjacent to the second region, the angle between the side wall surface and the surface of the second region being greater than or equal to 60° and less than 90°, so that the first passivation contact structure is formed with a shielding portion shielding a portion of the second region; and

[0008] A second passivation contact structure, the second passivation contact structure includes a second passivation layer and a second doping layer, the second passivation layer is arranged on the second region and extends from the second region to the side wall surface and at least a portion of the back surface of the first passivation contact structure, and the second doping layer is arranged on the second passivation layer.

[0009] In some embodiments, an angle between the sidewall surface and a surface of the second region is 60°-85°.

[0010] In some embodiments, an angle between the sidewall surface and a surface of the second region is 75°-85°.

[0011] In some embodiments, a portion of the second passivation layer located on the sidewall surface has a thickness of 5 nm to 40 nm.

[0012] In some embodiments, a portion of the second passivation layer located on the sidewall surface has a thickness of 6 nm to 14 nm.

[0013] In some embodiments, the thickness of the portion of the second passivation layer located on the side wall surface gradually increases in the direction approaching the back surface of the first passivation contact structure, and the thickness of the portion of the second doping layer located on the side wall surface also gradually increases in the direction approaching the back surface of the first passivation contact structure.

[0014] In some embodiments, the thickness of a portion of the second passivation layer located in an area of ​​the second region blocked by the blocking portion gradually decreases in a direction approaching the first passivation contact structure, and the thickness of a portion of the second doping layer located in an area of ​​the second region blocked by the blocking portion also gradually decreases in a direction approaching the first passivation contact structure.

[0015] In some embodiments, the length of the shielding portion in the arrangement direction of the first region and the second region is 20 nm-350 nm.

[0016] In some embodiments, an insulating dielectric layer is disposed on the back surface of the first passivation contact structure, and the second passivation layer and the second doping layer both extend onto the insulating dielectric layer.

[0017] In some embodiments, the insulating dielectric layer has a suspended segment protruding out of the first passivation contact structure and suspended above the second region, and the second passivation layer and the second doping layer surround the suspended segment in an arrangement direction of the first region and the second region.

[0018] In some embodiments, the length of the suspended segment protruding out of the first passivation contact structure is 10 nm-20 nm.

[0019] In some embodiments, the back-contact battery also includes a first transparent conductive film and a second transparent conductive film, the first transparent conductive film is arranged in the first region and is in conductive contact with the first doped layer, the second transparent conductive film is arranged on a portion of the second doped layer corresponding to the second region and is in conductive contact with the second doped layer, and the second transparent conductive film is insulated and spaced apart from the first transparent conductive film.

[0020] In some embodiments, the second transparent conductive film extends from the second region to cover the second doped layer located on the side wall surface and the back surface of the first passivation contact structure, and the thickness of the portion of the second transparent conductive film located on the side wall surface gradually increases in a direction approaching the back surface of the first passivation contact structure.

[0021] In some embodiments, a thickness of a portion of the second transparent conductive film located on an area of ​​the second region shielded by the shielding portion gradually decreases in a direction approaching the first passivation contact structure.

[0022] In some embodiments, the first area is a polished area, the second area is a suede area, and a thickness of a portion of the second transparent conductive film corresponding to the second area is less than a thickness of the first transparent conductive film.

[0023] In some embodiments, a portion of the second transparent conductive film corresponding to the second region has a thickness of 50 nm to 90 nm, and a thickness of the first transparent conductive film has a thickness of 75 nm to 150 nm.

[0024] In some embodiments, a ratio between a thickness of the first transparent conductive film and a thickness of a portion of the second transparent conductive film corresponding to the second region is 1.1-1.8.

[0025] In some embodiments, the second transparent conductive film has a conductive extension portion extending to cover the second doping layer located on the first region, the thickness of the conductive extension portion is greater than the thickness of the portion of the second transparent conductive film corresponding to the second region, and the thickness of the conductive extension portion is the same as the thickness of the first transparent conductive film.

[0026] The present application also provides a battery assembly, which includes a plurality of back-contact batteries as described in any one of the above items.

[0027] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0028] In the back-contact cell, cell assembly and photovoltaic system of the embodiments of the present application, a first passivation contact structure is arranged on the first region, the first passivation contact structure may include a first passivation layer and a first doping layer, the angle between the side wall surface of the first passivation contact structure and the surface of the second region is greater than or equal to 60° and less than 90°, so that the first doping layer forms a shielding portion that shields part of the second region, and the second passivation contact structure is arranged on the second region, the second passivation contact structure includes a second passivation layer and a second doping layer, the second passivation layer is stacked on the second region and extends from the second region to the side wall surface and at least a portion of the back surface of the first passivation contact structure, and the second doping layer is arranged on the second passivation layer. In this way, by setting the angle between the side wall surface of the first passivation contact structure and the surface of the second region to be greater than or equal to 60° and less than 90°, the first passivation contact structure can form a sloped terrace-shaped shielding portion. In the subsequent process of depositing the second passivation layer and the second doping layer, the setting of such an inclined angle of the side wall surface can optimize the conformal deposition of the second passivation layer on the side wall surface, avoid the second passivation layer on the side wall surface being too thin or even certain areas having no second passivation layer, enhance the passivation effect on the side wall surface of the first passivation contact structure, reduce the dark state recombination current, and enhance the fill factor (FF) and short circuit current (Jsc) of the back contact battery, thereby improving the performance of the back contact battery.

[0029] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a module schematic diagram of a photovoltaic system provided in an embodiment of the present application;

[0031] Figure 2 is a module schematic diagram of a battery assembly provided in an embodiment of the present application;

[0032] Figure 3 is a schematic diagram of the planar structure of a back contact battery provided in an embodiment of the present application;

[0033] Figure 4 yes Figure 3 Schematic diagram of the cross-sectional structure of the middle back contact battery along line IV-IV;

[0034] Figure 5 is another schematic cross-sectional structure diagram of a back contact battery provided in an embodiment of the present application;

[0035] Figure 6 is another schematic cross-sectional structure diagram of a back contact battery provided in an embodiment of the present application;

[0036] Figure 7This is another schematic cross-sectional structure diagram of the back contact battery provided in the embodiment of the present application.

[0037] Description of main component symbols:

[0038] Photovoltaic system 1000, battery assembly 200, back contact battery 100, silicon substrate 10, first surface 11, second surface 12, first region 121, second region 122, first passivation contact structure 20, first passivation layer 21, first doping layer 22, side wall surface 201, back surface 202, shielding portion 203, second passivation contact structure 30, second passivation layer 31, second doping layer 32, insulating dielectric layer 40, suspended segment 41, first transparent conductive film 50, second transparent conductive film 60, conductive extension portion 61. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0040] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "lateral", "longitudinal", etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0042] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0043] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0044] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed in itself. In addition, the various specific processes and examples of materials provided by the present application, but those of ordinary skill in the art can be aware of the application of other processes and / or the use scenarios of other materials.

[0045] See also Figure 1-Figure 2 The photovoltaic system 1000 in the embodiment of the present application may include the battery assembly 200 in the embodiment of the present application, and the battery assembly 200 in the embodiment of the present application may include a plurality of back-contact batteries 100 in the embodiment of the present application.

[0046] In the embodiment of the present application, multiple back-contact cells 100 in the battery assembly 200 can be connected in series to form multiple battery strings, and each battery string can be connected in series, in parallel, or in series-parallel combination to realize the current bus output. For example, the connection between each battery cell can be realized by welding a welding strip, and the connection between each battery string can be realized by a bus bar. In some embodiments, each battery string can form a battery cell array, and then be packaged together by a front plate, a front adhesive film, a rear adhesive film and a back plate to form a battery assembly 200.

[0047] See also Figure 3-Figure 5 The back contact cell 100 in the embodiment of the present application may include a silicon substrate 10 , a first passivation contact structure 20 and a second passivation contact structure 30 .

[0048] like Figure 4 As shown, the silicon substrate 10 has a first surface 11 and a second surface 12 opposite to each other, wherein the first surface 11 may be the light-facing surface of the silicon substrate 10 , the second surface 12 may be the backlight surface of the silicon substrate 10 , and the second surface 12 may include adjacent first regions 121 and second regions 122 .

[0049] like Figure 3 As shown, in some embodiments, the second surface 12 may include a plurality of first regions 121 and a plurality of second regions 122, the plurality of first regions 121 and the plurality of second regions 122 may be alternately arranged along a first direction, the first regions 121 and the second regions 122 may both extend along a second direction, and the second direction intersects with the first direction.

[0050] Specifically, Figure 3 As shown, the first region 121 and the second region 122 may be alternately arranged along the lateral direction of the silicon substrate 10 and both extend along the longitudinal direction, that is, the first direction may be the lateral direction of the back contact battery 100, and the second direction may be the longitudinal direction of the back contact battery 100, and the two directions are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction may also be other directions, for example, the two directions may be diagonal directions of the silicon substrate 10, respectively, and the specifics are not limited here.

[0051] See also Figure 4 and Figure 5 , the first passivation contact structure 20 is disposed on the first region 121, and each first region 121 is provided with the first passivation contact structure 20. The first passivation contact structure 20 may include a first passivation layer 21 and a first doping layer 22, and the first passivation layer 21 and the first doping layer 22 are sequentially stacked on the first region 121 along the direction facing away from the second surface 12, that is, along the thickness direction of the back contact battery 100, the first passivation layer 21 and the first doping layer 22 are sequentially stacked on the first region 121. In some embodiments, the first passivation layer 21 and the first doping layer 22 may completely cover the first region 121, and each first region 121 is provided with the first passivation layer 21 and the first doping layer 22.

[0052] Among them, Figure 4 and Figure 5As shown, the first passivation contact structure 20 has a back surface 202 facing away from the second surface 12 and a side wall surface 201 adjacent to the second region 122 (i.e., a surface jointly formed by the side surfaces of the first passivation layer 21 and the first doping layer 22 in the first direction), and an angle α between the side wall surface 201 and the surface of the second region 122 is greater than or equal to 60° and less than 90°, so that the first doping layer 22 forms a blocking portion 203 that blocks part of the second region 122.

[0053] That is, the side wall surface 201 of the first passivation contact structure 20 is inclined toward one side of the first region 121, so as to form a shielding portion 203 on the second region 122. The side wall surface 201 is the surface of the shielding portion 203 facing the second region 122, and the side wall surface 201 and the surface of the second region 122 form an acute angle greater than or equal to 60°, that is, 60°≤α<90°.

[0054] like Figure 4 and Figure 5 As shown, the second passivation contact structure 30 is disposed on the second region 122, and each second region 122 is provided with the second passivation contact structure 30, and the polarity of the second passivation contact structure 30 is opposite to the polarity of the first passivation contact structure 20. The second passivation contact structure 30 includes a second passivation layer 31 and a second doping layer 32, and the second passivation layer 31 and the second doping layer 32 are sequentially stacked on the second region 122 in the direction facing away from the second surface 12, that is, along the thickness direction of the back contact battery 100, the second passivation layer 31 and the second doping layer 32 are sequentially stacked on the second region 122, and the polarity of the second doping layer 32 is opposite to that of the first doping layer 22. In some embodiments, the second passivation layer 31 and the second doping layer 32 can completely cover the second region 122, and each second region 122 is provided with the second passivation layer 31 and the second doping layer 32.

[0055] like Figure 4 and Figure 5 As shown, in the second passivation contact structure 30, the second passivation layer 31 is stacked on the second region 122 and extends from the second region 122 to the sidewall surface 201 and at least a portion of the back surface 202 of the first passivation contact structure, and the second doping layer 32 is disposed on the second passivation layer 31. That is, in addition to covering the second region 122, the second passivation contact structure 30 also extends to the sidewall surface 201 of the first passivation contact structure 20 and extends to cover at least a portion of the back surface 202 of the first passivation contact structure 20.

[0056] It should be noted that, in this article, a certain layer structure covering a partial area or the entire area of ​​a certain surface may be a certain layer structure covering another layer structure, the layer structure may be directly stacked on the surface or a certain film layer, or other film layers may be arranged between the film layer and the surface or film layer, and the covering is only used to limit the specific setting range of the film layer. For example, in this article, the second passivation layer 31 extends and covers the back surface 202 of the first passivation contact structure 20, the second passivation layer 31 may directly cover the back surface 202 of the first passivation contact structure 20, or there may be an insulating dielectric layer 40 described below between the second passivation layer 31 and the back surface 202 of the first passivation contact structure 20, and the second passivation layer 31 is located on the insulating dielectric layer 40.

[0057] In addition, it should be noted that in the present application, the side wall surface 201 of the first passivation contact structure 20 can be a regular slope or an irregular slope, and the surface of the second region 122 can be a flat plane or an irregular plane. It only needs to be that at any cross section, the angle α between the line connecting any point on the side wall surface 201 of the first doping layer 22 and the intersection of the side wall surface 201 and the surface of the second region 122 and the surface of the second region 122 is an acute angle greater than or equal to 60°, and there is no specific limitation here.

[0058] In the back-contact cell 100, cell assembly 200 and photovoltaic system 1000 in the embodiments of the present application, a first passivation contact structure 20 is arranged on the first region 121, and the first passivation contact structure 20 may include a first passivation layer 21 and a first doping layer 22. The angle α between the side wall surface 201 of the first passivation contact structure 20 and the surface of the second region 122 is greater than or equal to 60° and less than 90°, so that the first doping layer 22 forms a shielding portion 203 that shields part of the second region 122. The second passivation contact structure 30 is arranged on the second region 122. The second passivation contact structure 30 includes a second passivation layer 31 and a second doping layer 32. The second passivation layer 31 is stacked on the second region 122 and extends from the second region 122 to the side wall surface 201 and at least a portion of the back surface 202 of the first passivation contact structure, and the second doping layer 32 is arranged on the second passivation layer 31. In this way, by setting the angle α between the side wall surface 201 of the first passivation contact structure 20 and the surface of the second region 122 to be greater than or equal to 60° and less than 90°, the first passivation contact structure 20 can form a sloped terrace-shaped shielding portion 203. In the subsequent process of depositing the second passivation layer 31 and the second doping layer 32, the setting of such an inclination angle of the side wall surface 201 can optimize the conformal deposition of the second passivation layer 31 on the side wall surface 201, avoid the second passivation layer 31 on the side wall surface 201 being too thin or even certain areas having the second passivation layer 31, enhance the passivation effect on the side wall surface 201 of the first passivation contact structure 20, reduce the dark state recombination current, and enhance the fill factor (FF) and short circuit current (Jsc) of the back contact battery 100, thereby improving the performance of the back contact battery 100.

[0059] That is to say, in the present application, by optimizing the design of the angle α between the side wall surface 201 of the first passivation contact structure 20 and the surface of the second region 122, the passivation effect of the second passivation layer 31 on the side wall surface 201 of the first passivation contact structure 20 can be improved during the subsequent deposition of the second passivation layer 31 and the second doping layer 32, thereby improving the performance of the back contact battery 100.

[0060] Specifically, in an embodiment of the present application, the angle α between the side wall surface 201 of the first passivation contact structure 20 and the surface of the second region 122 may be, for example, 60°, 62°, 64°, 66°, 68°, 70°, 72°, 74°, 76°, 78°, 80°, 82°, 84°, 85°, 86°, 87°, 88°, 89° or the like.

[0061] The silicon substrate 10 may be an N-type silicon substrate or a P-type silicon substrate, which is not limited here. The first doping layer 22 may be an N-type doping layer, and the second doping layer 32 may be a P-type doping layer, or the first doping layer 22 may be a P-type doping layer, and the second doping layer 32 may be a P-type doping layer, which is not limited here, as long as the polarities of the two are opposite.

[0062] In an embodiment of the present application, the back contact cell 100 may be a hybrid back contact cell, the first passivation layer 21 and the first doping layer 22 constitute a first passivation contact structure 20, the second passivation layer 31 and the second doping layer 32 constitute a second passivation contact structure 30, and the types of the passivation contact structures of the two are different.

[0063] In some embodiments, the first passivation contact structure 20 may be a tunneling passivation contact structure, and the second passivation contact structure 30 may be a heterojunction passivation contact structure. In such a back contact cell 100, the first doped layer 22 may be a doped polysilicon layer, and the first passivation layer 21 may be a tunneling oxide layer, for example, a tunneling silicon oxide layer, and the two form a tunneling passivation contact structure. The second passivation layer 31 may be an intrinsic amorphous silicon layer, and the second doped layer 32 may be at least one of a doped amorphous silicon layer and a doped microcrystalline silicon layer, and the two form a heterojunction passivation structure.

[0064] In this way, by designing the first doping layer 22 as a doped polysilicon layer and designing the second doping layer 32 as at least one of a doped amorphous silicon layer and a doped microcrystalline silicon layer, a hybrid back contact cell 100 can be formed to improve the efficiency of the back contact cell 100.

[0065] In a preferred embodiment, the first passivation layer 21 may be a tunneling oxide layer, the first doped layer 22 may be an N-type doped polysilicon layer, the second passivation layer 31 may be an intrinsic amorphous silicon layer, and the second doped layer 32 may be a P-type doped amorphous silicon layer or a P-type doped microcrystalline silicon layer. In this way, the first passivation layer 21 and the first doped layer 22 are arranged into a tunneling passivation contact structure, and the second passivation layer 31 and the first doped layer 22 are arranged into a heterojunction passivation contact structure. Compared with the case where the second passivation layer 31 is a tunneling passivation layer and the second doped half layer is a doped polysilicon layer or a doped microcrystalline silicon layer, the recombination rate of carriers can be reduced, and the conversion efficiency of the back contact battery 100 can be improved.

[0066] In some embodiments, the angle α between the sidewall surface 201 and the surface of the second region 122 is 60°-85°.

[0067] In this way, the angle α between the side wall surface 201 of the first passivation contact structure 20 and the surface of the second region 122 is set within the range of 60°-85°. This can improve the uniformity of the thickness of the portion of the second passivation layer 31 located on the side wall surface 201 while avoiding the poor passivation effect caused by the thickness of the portion of the second passivation layer 31 located on the side wall surface 201 being too thin, further optimize the passivation effect of the side wall surface 201 of the first passivation contact structure 20, reduce the dark state recombination current, and improve the performance of the back contact battery 100.

[0068] Specifically, in such an embodiment, the angle α between the side wall surface 201 and the surface of the second region 122 may be, for example, 60°, 61°, 62°, 63°, 64°, 65°, 66°, 67°, 68°, 69°, 70°, 71°, 72°, 73°, 74°, 75°, 76°, 77°, 78°, 79°, 80°, 81°, 82°, 83°, 84°, 85° or any value between 60° and 85°.

[0069] Further, in such an embodiment, the angle α between the side wall surface 201 and the surface of the second region 122 is preferably 75°-85°, such as 75°, 76°, 77°, 78°, 79°, 80°, 81°, 82°, 83°, 84°, 85°. Specifically, the inventors of the present application have found through research that setting the angle α between the two within the preferred range of 75°-85° can make the passivation effect of the side wall surface 201 of the first passivation contact structure 20 reach an ideal optimal state, thereby improving the performance of the back contact battery 100 as much as possible.

[0070] In some embodiments, the thickness of the portion of the second passivation layer 31 located on the sidewall surface 201 of the first passivation contact structure 20 is 5 nm-40 nm.

[0071] In this way, by setting the thickness of the second passivation layer 31 on the side wall surface 201 of the first passivation contact structure 20 within this reasonable range, the passivation effect at the side wall surface 201 can be improved, and by setting the angle α between the side wall surface 201 and the surface of the second region 122 within the above range, conformal deposition of the second passivation layer 31 can be achieved during the deposition process, so that the thickness of the second passivation layer 31 on the side wall surface 201 of the first doping layer 22 can be maintained within a reasonable range of 5nm-40nm, thereby improving the performance of the back contact battery 100.

[0072] Specifically, in such an embodiment, the thickness of the portion of the second passivation layer 31 located on the side wall surface 201 of the first passivation contact structure 20 may be, for example, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 12nm, 13nm, 14nm, 15nm, 16nm, 18nm, 20nm, 25nm, 30nm, 35nm, 40nm or any value between 5nm-40nm.

[0073] In such an embodiment, after repeated research and demonstration by the inventors of the present application, it was found that in order to achieve a better passivation effect, the thickness of the portion of the second passivation layer 31 located on the side wall surface 201 of the first passivation contact structure 20 may preferably be 6nm-14nm, for example, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm or any value between 6nm and 14nm.

[0074] See also Figure 5 In some embodiments, the thickness of the second passivation layer 31 located on the side wall surface 201 gradually increases in the direction approaching the back surface 202 of the first passivation contact structure 20, and the thickness of the second doping layer 32 located on the side wall surface 201 also gradually increases in the direction approaching the back surface 202 of the first passivation contact structure 20.

[0075] In this way, while ensuring the thickness of the second passivation layer 31, the thickness of the second passivation layer 31 and the second doping layer 32 on the side wall surface 201 of the first doping layer 22 is set to gradually increase, which can significantly improve the isolation effect between the second doping layer 32 and the first doping layer 22 while ensuring the passivation effect, significantly reduce the short-circuit effect between the two, and further improve the performance of the back contact battery 100. In addition, by designing the thickness of the part of the second passivation layer 31 on the side wall surface 201 to change in this way, the film structure stress of the second passivation layer 31 can be relieved, and the stability of the battery structure can be improved.

[0076] Please continue reading Figure 5 In some embodiments, the thickness of the second passivation layer 31 located in the area of ​​the second region 122 blocked by the blocking portion 203 gradually decreases in the direction approaching the first passivation contact structure 20, and the thickness of the second doping layer 32 located in the area of ​​the second region 122 blocked by the blocking portion 203 also gradually decreases in the direction approaching the first passivation contact structure 20.

[0077] In this way, the thickness of the portion of the second passivation layer 31 and the second doping layer 32 located on the second region 122 and close to the first passivation contact structure 20 can be gradually reduced, thereby improving the electrical isolation performance between the second passivation layer 31 and the second doping layer 32 located on the second region 122 and the first passivation contact structure 20, reducing the short-circuit effect between the second passivation layer 31 and the second doping layer 32 located on the second region 122 and the first passivation contact structure 20, and further improving the performance of the back contact battery 100. In addition, by designing the thickness of the portion of the second passivation layer 31 and the second doping layer 32 located at the position of the shielded area to change in this way, the structural stress of the film layer can also be alleviated, and the stability of the battery structure can be improved.

[0078] See also Figure 4 and Figure 5 In some embodiments, the length L1 of the shielding portion 203 in the arrangement direction of the first region 121 and the second region 122 (ie, the first direction shown in the figure and described above) is 20 nm-350 nm.

[0079] In this way, by setting the length L1 of the blocking portion 203 within this reasonable range, the angle α between the side wall surface 201 of the first doping layer 22 and the second region 122 can be within the reasonable range described above. At the same time, during the deposition process, the thickness of the second passivation layer 31 on the side wall surface 201 can be ensured to be within the reasonable range described above, thereby improving the performance of the back contact battery 100.

[0080] Specifically, in such an embodiment, the thickness of the first passivation layer 21 may be 1.5nm-3nm, and the thickness of the first doping layer 22 may be 50nm-600nm. The length L1 of the shielding portion 203 in the arrangement direction (i.e., the first direction) of the first region 121 and the second region 122 may be, for example, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 85nm, 90nm, 95nm, 100nm, 120nm, 140nm, 160nm, 180nm, 200nm, 220nm, 240nm, 260nm, 280nm, 300nm, 310nm, 320nm, 330nm, 340nm, 350nm or any value between 20nm-350nm.

[0081] Please continue reading Figure 4 and Figure 5 In some embodiments, an insulating dielectric layer 40 is disposed on the back surface 202 of the first passivation contact structure 20 , and the second passivation layer 31 and the second doping layer 32 are both extended and stacked to cover the insulating dielectric layer 40 .

[0082] Thus, by disposing the insulating dielectric layer 40 , the second passivation layer 31 and the second doping layer 32 on the back surface 202 of the first doping layer 22 can be separated from the first doping layer 22 , thereby reducing the risk of leakage between the second doping layer 32 and the first doping layer 22 .

[0083] Specifically, in the embodiment of the present application, the insulating medium layer 40 may be made of an insulating material, and may be a single-layer film structure or a multi-layer film structure, which is not specifically limited herein.

[0084] In some embodiments, the insulating dielectric layer 40 may be a single-layer film structure composed of an aluminum oxide film layer or a silicon nitride film layer. Of course, in some embodiments, the insulating dielectric layer 40 may also be a double-layer film structure composed of an aluminum oxide film layer and a silicon nitride film layer. For example, in some embodiments, the aluminum oxide film layer and the silicon nitride film layer may be stacked in sequence in a direction away from the second surface 12. In other embodiments, the silicon nitride film layer and the aluminum oxide film layer may be stacked in sequence in a direction away from the second surface 12.

[0085] That is, in the embodiment of the present application, the insulating dielectric layer 40 may include at least one of an aluminum oxide film layer and a silicon nitride film layer, which is not specifically limited herein.

[0086] In some embodiments, the insulating dielectric layer 40 may also contain the same doping element as the doping element in the first doping layer 22 , which is not specifically limited herein.

[0087] See also Figure 6 In some embodiments, the insulating dielectric layer 40 has a suspended segment 41 that protrudes out of the first passivation contact structure 20 and is suspended above the second region 122, and the second passivation layer 31 and the second doping layer 32 surround the suspended segment 41 in the arrangement direction of the first region 121 and the second region 122.

[0088] Thus, by setting the suspended section 41, a deposition area with a relative spacing can be provided between the suspended section 41 and the silicon substrate 10. In the subsequent deposition of the second passivation layer 31 and the second doping layer 32, the setting of such a deposition area can suppress the full exchange of plasma components in the area with plasma components outside the area, thereby realizing the localized distribution of the mobile hydrogen content of the second passivation layer 31, so that the mobile hydrogen content of the second passivation layer 31 in the deposition area is lower, and the mobile hydrogen content of the second passivation layer 31 in the remaining area is higher, so as to achieve the best passivation and anti-attenuation effect. In addition, the direct bombardment of the plasma on the silicon substrate 10 can be reduced, reducing bombardment damage.

[0089] In some embodiments, the length of the suspended segment 41 protruding out of the first passivation contact structure 20 is 10 nm-20 nm.

[0090] In this way, it can be avoided that the protruding length of the suspended section 41 is too long, which may cause the second passivation layer 31 on the sidewall surface 201 of the first passivation contact structure 20 to be difficult to grow to a desired thickness during the deposition process.

[0091] Specifically, in such an embodiment, the protruding length of the suspended segment 41 may be, for example, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm, 20nm or any value between 10nm and 20nm, and is not specifically limited here.

[0092] Of course, it is understandable that in some embodiments, the insulating dielectric layer 40 may not have the suspended segment 41 , and this is not specifically limited herein.

[0093] See also Figure 4-Figure 6 In some embodiments, the back contact battery 100 may further include a first transparent conductive film 50 and a second transparent conductive film 60. The first transparent conductive film 50 is disposed in the first region 121 and is in conductive contact with the first doping layer 22. The second transparent conductive film 60 is disposed on a portion of the second doping layer 32 corresponding to the second region 122 and is in conductive contact with the second doping layer 32. The first transparent conductive film 50 and the second transparent conductive film 60 are disposed with an insulating interval.

[0094] In this way, the arrangement of the first transparent conductive film 50 and the second transparent conductive film 60 can realize the extraction of current.

[0095] Specifically, in such an embodiment, both the first transparent conductive film 50 and the second transparent conductive film 60 may be transparent conductive film layers such as TCO film layers. It should be noted that, in such an embodiment, electrodes (not shown) may also be provided on the first transparent conductive film 50 and the second transparent conductive film 60 to facilitate welding in the subsequent process of forming components. For example, electrodes such as copper electrodes may be formed on partial regions of the first transparent conductive film 50 and the second transparent conductive film 60 by electroplating.

[0096] In this article, the part of a certain structure (such as a film layer, a conductive structure, etc.) corresponding to a certain region or a certain layer of structure refers to the part of the structure stacked on the region or the certain layer of structure. For example, the part of the second doped layer 32 corresponding to the second region 122 refers to the part of the second doped layer 32 stacked and covering the second region 122. If there is a similar description below, please refer to this for understanding.

[0097] Furthermore, if Figure 4As shown, in such an embodiment, when the second passivation layer 31 and the second doping layer 32 completely cover the entire back surface 202 of the first doping layer 22, a through groove 301 may be formed on the second passivation layer 31 and the second doping layer 32 located on the back surface 202 of the first doping layer 22 to partially expose the first doping layer 22, and the first transparent conductive film 50 may be disposed at the through groove 301 and in conductive contact with the first doping layer 22.

[0098] Of course, when the second passivation layer 31 and the second doping layer 32 only cover a portion of the first doping layer 22 , the first transparent conductive film 50 may be disposed on the region of the first doping layer 22 that is not covered by the extension portion.

[0099] In addition, if Figure 4 and Figure 6 As shown, when an insulating dielectric layer 40 is provided between the second passivation layer 31 and the back surface 202 of the first doping layer 22 and the second passivation layer 31 , the insulating dielectric layer 40 and the second doping layer 32 all completely cover the first doping layer 22 , the through groove 301 also penetrates the insulating dielectric layer 40 to expose the first doping layer 22 .

[0100] In addition, in some embodiments, the first transparent conductive film 50 and the second transparent conductive film 60 may be formed by first depositing a whole layer of conductive film on the entire back by deposition or the like, and then forming the first transparent conductive film 50 and the second transparent conductive film 60 insulated from each other by opening insulating grooves. Of course, in some embodiments, the two may also be prepared separately, which is not specifically limited here.

[0101] See also Figure 5 In some embodiments, the second transparent conductive film 60 may also extend from the second region 122 to cover the side wall surface 201 of the first passivation contact structure 20 and the second doping layer 32 located on the back surface 202 of the first passivation contact structure 20. In such a case, the thickness of the portion of the second transparent conductive film 60 located on the side wall surface 201 gradually increases in the direction approaching the back surface 202 of the first passivation contact structure 20.

[0102] In this way, the electrical isolation effect between the second transparent conductive film 60 and the first passivation contact structure 20 can be improved, and the short circuit effect between the second transparent conductive film 60 and the first passivation contact structure 20 can be significantly reduced. At the same time, by optimizing the angle α between the side wall surface 201 and the surface of the second region 122, the thickness uniformity of the portion of the second transparent conductive film 60 located on the side wall surface 201 can be better, further improving the passivation effect, and avoiding the thickness of the portion of the second transparent conductive film 60 located on the side wall surface 201 being too small or even the effective area not having the second transparent conductive film 60, thereby reducing the passivation effect. At the same time, by such a thickness variation design on the side wall surface 201, the structural stress of the film layer can be relieved, and the stability of the battery structure can be improved.

[0103] Also, please read Figure 5 In some embodiments, the thickness of the portion of the second transparent conductive film 60 located on the area of ​​the second region 122 blocked by the blocking portion 203 gradually decreases in a direction approaching the first passivation contact structure 20 .

[0104] In this way, the short circuit effect between the portion of the second transparent conductive film 60 corresponding to the second region 122 and the first passivation contact structure 20 can be reduced, thereby further improving the performance of the back contact battery 100. At the same time, by adopting such a thickness variation design in the shielded area, the structural stress of the film layer can also be alleviated, thereby improving the stability of the battery structure.

[0105] In some embodiments, the second transparent conductive film 60 may be disposed only on the portion of the second doping layer 32 corresponding to the second region 122. Figure 4 In other embodiments, the second transparent conductive film 60 may also have a conductive extension portion 61 extending to cover the second doping layer 32 located on the first region 121, and the conductive extension portion 61 is insulated and isolated from the first transparent conductive film 50. That is to say, in the present application, the specific setting range of the second transparent conductive film 60 is not limited, and it is only necessary to control the second transparent conductive film 60 and the first transparent conductive film 50 to be insulated from each other and to control the second transparent conductive film 60 not to have a direct conductive contact interface with the first doping layer 22.

[0106] Furthermore, in some embodiments, the back contact cell 100 may not have the insulating dielectric layer 40. In this case, the first passivation layer 21 is a tunneling layer, the first doped layer 22 is a doped polycrystalline silicon layer, the second passivation layer 31 is an intrinsic amorphous silicon layer, and the second doped layer 32 is a doped amorphous silicon layer and / or a doped microcrystalline silicon layer. The lateral conductivity of the second doped layer 32 is relatively poor, and the second transparent conductive film 60 can be disposed only on the second region 122 (i.e., without the conductive extension 61 described above). In this way, even if the insulating dielectric layer 40 is not present, the leakage risk can be effectively reduced.

[0107] Of course, in such an embodiment, in the absence of the insulating dielectric layer 40, the second transparent conductive film 60 may also have the conductive extension portion 61 described above. In such a case, in the area covered by the conductive extension portion 61, the first passivation contact structure 20 and the second passivation contact structure 30 are leak-conducted in the thickness direction to form a leakage point, thereby reducing the reverse breakdown voltage of the back contact battery 100. It is only necessary to control the overall leakage area of ​​the entire back contact battery 100 to avoid affecting the efficiency of the back contact battery 100.

[0108] See also Figure 4 In some embodiments, the first region 121 may be a polished region (i.e., the surface of the first region 121 is a polished surface), the second region 122 may be a velvet region (i.e., the surface of the second region 122 is velvet), and the thickness H1 of the portion of the second transparent conductive film 60 corresponding to the second region 122 is less than the thickness H2 of the first transparent conductive film 50, i.e., H1<H2.

[0109] In this way, setting the second area 122 to a velvet surface can reduce the reflectivity of the back light, thereby improving the double-sidedness. At the same time, the thickness H1 of the second transparent conductive film 60 located on the upper part of the second area 122 is set to be smaller. When the back light enters, the parasitic absorption in the second area 122 can be reduced, thereby further improving the double-sidedness of the back contact battery 100.

[0110] Further, in such an embodiment, the first passivation contact structure 20 is a tunnel passivation contact structure, that is, the first passivation layer 21 can be a tunneling layer, the first doped layer 22 is a doped polycrystalline silicon layer, and the second passivation contact structure 30 is a heterojunction passivation contact structure, that is, the second passivation layer 31 is an intrinsic amorphous silicon layer, and the second doped layer 32 is a doped amorphous silicon layer and / or a doped microcrystalline silicon layer. In this way, the area corresponding to the doped polycrystalline silicon is set as the polishing area 121, which can avoid the passivation effect of the area corresponding to the doped polycrystalline silicon being greatly reduced and affecting the efficiency, while the passivation effect of the doped amorphous silicon and / or the doped microcrystalline silicon is better, and the area corresponding to the doped amorphous silicon and / or the doped microcrystalline silicon is set as a velvet surface, which can improve the anti-reflection effect of the back side, thereby improving the bifaciality of the back contact battery 100. That is to say, in such a case, while ensuring the passivation effect at the first area 121 and the second area 122, the bifaciality of the back contact battery 100 can be further improved.

[0111] In some embodiments, the thickness H1 of the portion of the second transparent conductive film 60 corresponding to the second region 122 may be 50 nm to 90 nm. The thickness H2 of the first transparent conductive film 50 may be 75 nm to 150 nm.

[0112] Thus, on the one hand, by setting the thickness H1 of the portion of the second transparent conductive film 60 corresponding to the second region 122 within this reasonable range, it is possible to avoid the portion of the second transparent conductive film 60 corresponding to the second region 122 being too thin, which would result in excessive difficulty in manufacturing, and to avoid the portion of the second transparent conductive film 60 corresponding to the second region 122 being too thin, which would result in poor passivation effect on the second doping layer 32, and ... and to avoid the portion of the second transparent conductive film 60 corresponding to the second region 122 being too thin, and to avoid the portion of the second transparent conductive film 60 corresponding to the first polarity doping layer 22 being too thin, and to avoid the portion of the second transparent conductive film 60 corresponding to the first polarity doping layer 22 being too thin, and to avoid the portion of the second transparent conductive film 60 corresponding to the second region 122 being too thin, and to avoid the portion of the second transparent conductive film 60 corresponding to the second region 122 being too thin, and to avoid the portion of the second transparent conductive film 60 corresponding to the second region 122 being too thin, and to avoid the portion of the second transparent conductive film 60 corresponding to the second region 122 being too thin, and to avoid the portion of the second transparent conductive film 60 corresponding to the second region 122 being too thin, and to avoid the portion of the second transparent conductive film 60 corresponding to the second region 122 being too thin, and to avoid the portion of the second transparent conductive film 60 corresponding to the second region 122 being too thin, and to avoid

[0113] In other words, by setting the thickness of the two within the above reasonable range, it is possible to reduce the process difficulty, ensure the passivation effect, control the cost, reduce the parasitic absorption on the back side and improve the double-sidedness.

[0114] Specifically, in such an embodiment, the thickness H1 of the portion of the second transparent conductive film 60 corresponding to the second region 122 may be, for example, 50nm, 52nm, 54nm, 56nm, 58nm, 60nm, 62nm, 64nm, 66nm, 68nm, 70nm, 72nm, 74nm, 76nm, 78nm, 80nm, 82nm, 84nm, 86nm, 88nm, 90nm or any value between 50nm-90nm, which is not limited here. The thickness H1 of the first transparent conductive film 50 may be, for example, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, 105nm, 110nm, 115nm, 120nm, 125nm, 130nm, 135nm, 140nm, 145nm, 150nm or any value between 75nm-150nm, which is not limited here.

[0115] In some embodiments, the ratio between the thickness H2 of the first transparent conductive film 50 and the thickness H2 of the portion of the second transparent conductive film 60 corresponding to the textured area is 1.1-1.8, that is, the ratio between H2 and H1 is 1.1-1.8.

[0116] Thus, by setting the ratio between the thickness H2 of the first transparent conductive film 50 and the thickness H2 of the portion of the second transparent conductive film 60 corresponding to the suede area within this reasonable range, the parasitic absorption and passivation effects on the second surface 12 can be matched better.

[0117] Specifically, in such an embodiment, the ratio between the two may be, for example, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8 or any value between 1.1 and 1.8, and is not limited here.

[0118] See also Figure 4 In some embodiments, the second transparent conductive film 60 may have a conductive extension portion 61 extending to cover the second doping layer 32 located on the first region 121, and the thickness H3 of the conductive extension portion 61 is greater than the thickness H1 of the portion of the second transparent conductive film 60 corresponding to the second region 122, and the thickness H3 of the conductive extension portion 61 is the same as the thickness H1 of the first transparent conductive film 50, that is, H1<H2 and H2=H3.

[0119] In this way, the parasitic absorption in the second region 122 can be reduced while the passivation effect in the first region 121 can be improved.

[0120] See also Figure 4-Figure 6In some embodiments, in the thickness direction of the back contact battery 100, the surface of the second region 122 may be substantially flush with the surface of the first region 121. In this case, the second passivation layer 31 and the second doping layer 32 extend directly along the side wall surface 201 to the first passivation contact structure 20.

[0121] like Figure 7 As shown, in other embodiments, in the thickness direction of the back contact battery 100, the surface of the second region 122 may be closer to the first surface 11 than the surface of the first region 121. In this case, the position of the silicon substrate 10 corresponding to the first region 121 is a convex portion, and the side surface of the convex portion may be a continuous surface with the side wall surface 201. In this case, the second passivation layer 31 and the second doping layer 32 may extend from the side surface of the convex portion to the side wall surface 201 of the first passivation contact structure 20, and then extend to at least a portion of the back surface 202 of the first passivation contact structure 20. In this case, the thickness of the portion of the second passivation layer 31 located on the side surface of the convex portion is less than the thickness of the portion of the second passivation layer 31 located on the side wall surface 201.

[0122] In the description of this specification, the description with reference to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0123] In addition, the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A back contact battery, characterized in that: include: A silicon substrate having a first surface and a second surface opposite to each other, wherein the second surface includes adjacent first and second regions; a first passivation contact structure disposed on the first region, the first passivation contact structure comprising a first passivation layer and a first doping layer sequentially stacked on the first region, the first passivation contact structure having a back surface away from the second surface and a sidewall surface adjacent to the second region, the angle between the sidewall surface and the surface of the second region being greater than or equal to 60° and less than 90°, so that the first passivation contact structure is formed with a shielding portion shielding a portion of the second region; and A second passivation contact structure, the second passivation contact structure includes a second passivation layer and a second doping layer, the second passivation layer is arranged on the second region and extends from the second region to the side wall surface and at least a portion of the back surface of the first passivation contact structure, and the second doping layer is arranged on the second passivation layer.

2. The back contact cell according to claim 1, characterized in that: The angle between the side wall surface and the surface of the second region is 60°-85°.

3. The back contact battery according to claim 2, characterized in that: The angle between the side wall surface and the surface of the second region is 75°-85°.

4. The back contact cell according to claim 1, characterized in that: The thickness of the portion of the second passivation layer located on the side wall surface is 5 nm-40 nm.

5. The back contact cell according to claim 4, characterized in that: The thickness of the portion of the second passivation layer located on the sidewall surface is 6 nm-14 nm.

6. The back contact cell according to any one of claims 1 to 5, characterized in that: The thickness of the second passivation layer located on the side wall surface gradually increases in the direction approaching the back surface of the first passivation contact structure, and the thickness of the second doping layer located on the side wall surface also gradually increases in the direction approaching the back surface of the first passivation contact structure.

7. The back contact cell according to any one of claims 1 to 5, characterized in that: The thickness of the second passivation layer located in the area of ​​the second region blocked by the blocking portion gradually decreases in the direction approaching the first passivation contact structure, and the thickness of the second doped layer located in the area of ​​the second region blocked by the blocking portion also gradually decreases in the direction approaching the first passivation contact structure.

8. The back contact cell according to claim 1, characterized in that: The length of the shielding portion in the arrangement direction of the first region and the second region is 20 nm-350 nm.

9. The back contact cell according to claim 1, characterized in that: An insulating dielectric layer is disposed on the back surface of the first passivation contact structure, and the second passivation layer and the second doping layer both extend onto the insulating dielectric layer.

10. The back contact cell according to claim 9, characterized in that: The insulating dielectric layer has a suspended segment protruding out of the first passivation contact structure and suspended above the second region, and the second passivation layer and the second doping layer surround the suspended segment in an arrangement direction of the first region and the second region.

11. The back contact cell according to claim 10, characterized in that: The length of the suspended section protruding out of the first passivation contact structure is 10 nm-20 nm.

12. The back contact cell according to claim 1, characterized in that: The back-contact battery also includes a first transparent conductive film and a second transparent conductive film, the first transparent conductive film is arranged in the first region and is in conductive contact with the first doped layer, the second transparent conductive film is arranged on a portion of the second doped layer corresponding to the second region and is in conductive contact with the second doped layer, and the second transparent conductive film is insulated and spaced apart from the first transparent conductive film.

13. The back contact cell according to claim 12, characterized in that: The second transparent conductive film extends from the second region to cover the second doped layer located on the side wall surface and the back surface of the first passivation contact structure, and the thickness of the portion of the second transparent conductive film located on the side wall surface gradually increases in a direction approaching the back surface of the first passivation contact structure.

14. The back contact cell according to claim 13, characterized in that: The thickness of a portion of the second transparent conductive film located on an area of ​​the second region shielded by the shielding portion gradually decreases in a direction approaching the first passivation contact structure.

15. The back contact cell according to claim 12, characterized in that: The first area is a polished area, the second area is a suede area, and the thickness of a portion of the second transparent conductive film corresponding to the second area is less than the thickness of the first transparent conductive film.

16. The back contact cell according to claim 15, characterized in that The thickness of the second transparent conductive film corresponding to the second region is 50 nm-90 nm, and the thickness of the first transparent conductive film is 75 nm-150 nm.

17. The back contact cell according to claim 15, characterized in that: The ratio between the thickness of the first transparent conductive film and the thickness of a portion of the second transparent conductive film corresponding to the second region is 1.1-1.

8.

18. The back contact cell according to claim 15, characterized in that The second transparent conductive film has a conductive extension portion extending to cover the second doping layer located on the first region, the thickness of the conductive extension portion is greater than the thickness of the portion of the second transparent conductive film corresponding to the second region, and the thickness of the conductive extension portion is the same as the thickness of the first transparent conductive film.

19. A battery assembly, characterized in that: A back contact battery comprising any one of claims 1-18.

20. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 19.

Images