Back contact cell, cell assembly and photovoltaic system

Abstract

The utility model relates to the technical field of solar cells, and provides a back contact cell, a cell assembly and a photovoltaic system, an insulation region is arranged between a first region and a second region of a backlight surface of a silicon substrate of the back contact cell, a first passivation layer and a first doping layer are arranged in the first region, and a second passivation layer and a second doping layer are arranged in the second region. A first insulating dielectric layer is arranged on the insulating region, the first insulating dielectric layer is provided with an insulating extension section extending to the first doping layer, and the passivation extension section of the second passivation layer and the doping extension section of the second doping layer only cover the part, corresponding to the insulating region, in the first insulating dielectric layer and do not extend to the first doping layer. Therefore, through the arrangement of the insulating region and the first insulating dielectric layer, the electrical isolation effect between the insulating region and the first insulating dielectric layer can be improved, the risk of short-circuit electric leakage is reduced, and 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, the back-contact cell is a cell in which both the emitter and base contact electrodes are placed on the backlight side (non-light-receiving side) of the cell. The light-receiving side of the cell is not blocked by any metal electrode, thereby effectively increasing the short-circuit current of the cell.

[0003] In order to improve the efficiency of the back contact battery, one of the doped layers of the back contact battery 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 battery. That is, a hybrid back contact battery is formed by using two different passivation contact structures of opposite types.

[0004] However, in such a back-contact battery, there are processes such as etching during the deposition manufacturing process, which easily lead to the phenomenon that one of the two passivation contact structures of different passivation types covers part of the area of ​​the other. For example, it is easy for the P-type passivation contact structure to cover part of the area of ​​the N-type passivation contact structure, which can easily cause a short circuit and thus affect the performance of the back-contact battery. Utility Model Content

[0005] The present application provides a back-contact cell, a cell assembly, and a photovoltaic system.

[0006] The present application is implemented as follows: the back contact battery of the embodiment of the present application includes:

[0007] a silicon substrate having a light-receiving surface and a backlight surface facing each other, the backlight surface comprising a plurality of first regions and a plurality of second regions alternately arranged along a first direction, and the backlight surface further comprising an insulating region between the first regions and the second regions, the insulating region separating the first regions from the second regions, the first regions, the second regions, and the insulating spacer region all extending along a second direction, the second direction intersecting the first direction;

[0008] sequentially stacking a first passivation layer and a first doping layer on the first region;

[0009] A first insulating dielectric layer is provided on the insulating region, the first insulating dielectric layer has an insulating extension segment extending and stacked on the first doped layer, the insulating extension segment covering at least a portion of the first doped layer; and

[0010] A second passivation layer and a second doped layer are sequentially stacked on the second region, wherein the second doped layer has an opposite polarity to the first doped layer, the second passivation layer has a passivation extension segment extending and stacked on the insulating region, and the second doped layer has a doped extension segment extending and stacked on the passivation extension segment, and the passivation extension segment and the doped extension segment only cover the portion of the first insulating medium layer corresponding to the insulating region.

[0011] In some embodiments, the passivation extension and the doped extension are only disposed on a portion of the first insulating dielectric layer corresponding to the insulating region.

[0012] In some embodiments, a length of the insulating region in the first direction is 10 μm-600 μm.

[0013] In some embodiments, a length of the insulating region in the first direction is 10 μm-300 μm.

[0014] In some embodiments, a ratio between the lengths of the passivation extension and the doped extension in the first direction and the length of the insulating region in the first direction is 3%-50%.

[0015] In some embodiments, the insulating extension covers the entire first doped layer.

[0016] In some embodiments, the back contact battery further includes a third doping layer stacked and covering the insulating extension segment, the doping type of the third doping layer is the same as the doping type of the second doping layer, and the third doping layer is insulated from the second doping layer.

[0017] In some embodiments, the back-contact battery further includes a first conductive film and a second conductive film, wherein the first conductive film is at least arranged on a portion of the first zone and is in conductive contact with the first doped layer, and the second conductive film is at least formed on at least a portion of the second doped layer and is in conductive contact with the second doped layer, and the first conductive film and the second conductive film are insulated from each other.

[0018] In some embodiments, the insulating extension only covers a portion of the first doped layer, and the first conductive film is formed on at least a portion of the first doped layer not covered by the insulating extension; or

[0019] The insulating extension section covers the entire first doped layer. A groove is formed on the insulating extension section. Part of the first doped layer is exposed from the groove. The first conductive film is at least arranged on the portion of the first doped layer exposed from the groove.

[0020] In some embodiments, the first area is a polished area, the second area is a suede area, the first conductive film and the second conductive film are both transparent conductive films, and the thickness of the portion of the second conductive film corresponding to the second area is less than the thickness of the portion of the first conductive film corresponding to the first area.

[0021] In some embodiments, a portion of the second conductive film corresponding to the second region has a thickness of 50 nm to 90 nm, and a portion of the first conductive film corresponding to the first region has a thickness of 75 nm to 150 nm.

[0022] In some embodiments, a ratio between a thickness of a portion of the first conductive film corresponding to the first region and a thickness of a portion of the second conductive film corresponding to the second region is 1.1-1.8.

[0023] In some embodiments, the insulating region is a velvet region, the first conductive film has a first conductive extension portion, the first conductive extension portion extends to the portion of the first insulating medium layer corresponding to the insulating region and is insulated from the doped extension segment, and the thickness of the first conductive extension portion is less than the thickness of the portion of the first conductive film corresponding to the first region.

[0024] In some embodiments, the thickness of the first conductive extension portion is 40 nm-80 nm, and the thickness of a portion of the first conductive film corresponding to the first region is 75 nm-150 nm.

[0025] In some embodiments, a ratio between a thickness of a portion of the first conductive film corresponding to the first region and a thickness of the first conductive extension is 1.3-2.

[0026] In some embodiments, the insulating region is velvet-finished, the surface roughness of the second region is less than the surface roughness of the insulating region, the second conductive film has a second conductive extension portion extending to the doped extension segment, and the thickness of the second conductive extension portion is less than the thickness of the portion of the second conductive film corresponding to the second region.

[0027] In some embodiments, the thickness of the second conductive extension is 40 nm-80 nm, and the thickness of a portion of the second conductive film corresponding to the second region is 50 nm-90 nm.

[0028] In some embodiments, a ratio between a thickness of a portion of the second conductive film corresponding to the second region and a thickness of the second conductive extension is 1.1-2.

[0029] In some embodiments, the second conductive film further has a third conductive extension extending onto the insulating extension segment, and the thickness of the third conductive extension is greater than the thickness of the second conductive extension and also greater than the thickness of the portion of the second conductive film corresponding to the second region.

[0030] In some embodiments, the thickness of the third conductive extension is the same as the thickness of a portion of the first conductive film corresponding to the first region.

[0031] In some embodiments, the back-contact battery includes a metal electrode and a third conductive film, wherein the metal electrode is disposed on the first region and is in conductive contact with the first doped layer, the third conductive film is formed on at least a portion of the second doped layer and is in conductive contact with the second doped layer, and the third conductive film is insulated from the metal electrode;

[0032] The insulating extension section only covers a portion of the first doped layer, and the metal electrode is provided on a portion of the first doped layer not covered by the insulating extension section; or

[0033] The insulating extension segment covers the entire first doped layer. The metal electrode is disposed on the insulating extension segment and passes through the insulating extension segment to be in conductive contact with the first doped layer.

[0034] In some embodiments, the second region and the insulating region are both velvet regions, the surface roughness of the second region is less than the surface roughness of the insulating region, the third conductive film has a fourth conductive extension portion extending at least to the doped extension segment, and the thickness of the fourth conductive extension portion is less than the thickness of the portion of the third conductive film corresponding to the second region.

[0035] In some embodiments, the thickness of the fourth conductive extension portion is 40 nm-80 nm, and the thickness of a portion of the third conductive film corresponding to the second region is 50 nm-90 nm.

[0036] In some embodiments, a ratio between a thickness of a portion of the third conductive film corresponding to the second region and a thickness of the fourth conductive extension is 1.1-2.

[0037] In some embodiments, the third conductive film further has a fifth conductive extension portion extending onto the insulating extension segment, and a thickness of the fifth conductive extension portion is greater than a thickness of a portion of the third conductive film corresponding to the second region and greater than a thickness of the fourth conductive extension portion.

[0038] In some embodiments, the thickness of the fifth conductive extension is 75 nm-150 nm.

[0039] In some embodiments, the first region is a polished region, the insulating region is a suede region, and a thickness of a portion of the first insulating dielectric layer corresponding to the insulating region is smaller than a thickness of the insulating extension segment.

[0040] In some embodiments, a portion of the first insulating dielectric layer corresponding to the insulating region may have a thickness of 50 nm to 100 nm, and a thickness of the insulating extension segment may have a thickness of 60 nm to 150 nm.

[0041] In some embodiments, a ratio between a thickness of the insulating extension segment and a thickness of a portion of the first insulating dielectric layer corresponding to the insulating region is 1.1-2.

[0042] In some embodiments, there is a second insulating dielectric layer between the insulating extension segment and the first doped layer, the second insulating dielectric layer has a suspended segment extending along the first direction and protruding from the first region, the suspended segment is suspended on the insulating region, and the first insulating dielectric layer surrounds the suspended segment in the first direction.

[0043] In some embodiments, a thickness of a portion of the first insulating dielectric layer located on sides of the first passivation layer and the first doping layer gradually decreases in a direction approaching the suspended segment.

[0044] In some embodiments, a portion of the first insulating dielectric layer located on the surface of the suspended segment facing the silicon substrate gradually increases in size in a protruding direction of the suspended segment.

[0045] In some embodiments, the light-receiving surface is a velvet surface, the insulating region is a velvet region, and the surface roughness of the insulating region is smaller than the surface roughness of the light-receiving surface.

[0046] In some embodiments, a third passivation layer is formed on the light-receiving surface, and a thickness of the third passivation layer is smaller than a thickness of a portion of the first insulating dielectric layer corresponding to the insulating region.

[0047] In some embodiments, the silicon substrate further has several side surfaces connecting the light-receiving surface and the backlight surface, at least some of the side surfaces have a fourth passivation layer, and the thickness of the fourth passivation layer is greater than the thickness of the first insulating dielectric layer.

[0048] In some embodiments, the first passivation layer is a tunneling oxide layer, and the first doped layer is a doped polysilicon layer;

[0049] The second passivation layer is at least one of an intrinsic amorphous silicon layer or a tunneling oxide layer, and the second doped layer is at least one of a doped amorphous silicon layer and a doped microcrystalline silicon layer.

[0050] In some embodiments, the first insulating dielectric layer includes a first aluminum oxide film layer;

[0051] The silicon substrate also has several side surfaces connecting the light-receiving surface and the backlight surface, and the several side surfaces include at least one cutting surface, and the cutting surface has a second aluminum oxide film layer. The cutting surface includes a first area connected to the backlight surface and a second area farther away from the backlight surface than the first area. The ratio of oxygen and aluminum elements in the part of the second aluminum oxide film layer corresponding to the first area is greater than the ratio of oxygen and aluminum elements in the first aluminum oxide film layer.

[0052] In some embodiments, the ratio of oxygen to aluminum in the portion of the second aluminum oxide film layer corresponding to the first region is greater than the ratio of oxygen to aluminum in the portion of the second aluminum oxide film layer corresponding to the second region; and the ratio of oxygen to aluminum in the portion of the second aluminum oxide film layer corresponding to the second region is greater than the ratio of oxygen to aluminum in the first aluminum oxide film layer.

[0053] In some embodiments, a thickness of a portion of the second aluminum oxide film layer corresponding to the first region is greater than a thickness of the first aluminum oxide film layer.

[0054] In some embodiments, there is a fourth region between the first region and / or the second region closest to the edge of the silicon substrate and the edge of the silicon substrate, and a third insulating dielectric layer is provided on the fourth region, and the thickness of the third insulating dielectric layer is greater than the thickness of the first insulating dielectric layer.

[0055] In some embodiments, the first insulating dielectric layer includes a first aluminum oxide film layer, the third insulating dielectric layer includes a third aluminum oxide film layer, and the ratio of oxygen to aluminum in the third aluminum oxide film layer is greater than the ratio of oxygen to aluminum in the first aluminum oxide film layer.

[0056] The present application also provides a battery assembly, which includes several back-contact batteries as described in any one of the above items.

[0057] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0058] In the back-contact cell, cell assembly, and photovoltaic system of the embodiments of the present application, an insulating region is provided between the first and second regions of the backlight surface, a first passivation layer and a first doped layer are provided in the first region, a second passivation layer and a second doped layer are provided in the second region, a first insulating dielectric layer is provided on the insulating region, the first insulating dielectric layer has an insulating extension extending onto the first doped layer, the passivation extension of the second passivation layer and the doped extension of the second doped layer only cover the portion of the first insulating dielectric layer corresponding to the insulating region, and do not extend onto the first doped layer. In this way, by providing the insulating region and the first insulating dielectric layer, the first doped layer and the second doped layer can be insulated and isolated, which can improve the electrical isolation effect between the two. Moreover, during the manufacturing process, the passivation extension of the second passivation layer and the doped extension of the second doped layer can be made to extend and cover only the insulating region, and not cover the first doped layer, thereby forming a stacked structure in which two passivation contact structures of different polarities are stacked together in the first region, thereby reducing the risk of short circuit leakage and improving the performance of the back-contact cell. Furthermore, the provision of the first insulating dielectric layer and insulating extensions can enhance the surface passivation of the side and back surfaces of the insulating region and the first doped layer, reducing surface recombination and improving the efficiency of the back-contact cell. Furthermore, the provision of the passivation extensions and doped extensions can also enhance hydrogen passivation in the insulating region.

[0059] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a module schematic diagram of a photovoltaic system provided by an embodiment of the present application;

[0061] Figure 2 Schematic diagram of a module of a battery assembly provided in an embodiment of the present application;

[0062] Figure 3 Schematic diagram of the planar structure of a back-contact battery provided in an embodiment of the present application;

[0063] Figure 4 yes Figure 3 Schematic diagram of the cross-sectional structure of the middle back contact battery along line IV-IV;

[0064] Figure 5 1 is another schematic cross-sectional structure diagram of a back-contact battery provided in an embodiment of the present application;

[0065] Figure 6 1 is another schematic cross-sectional structure diagram of a back-contact battery provided in an embodiment of the present application;

[0066] Figure 7is another schematic cross-sectional structure diagram of a back-contact battery provided in an embodiment of the present application;

[0067] Figure 8 1 is another schematic cross-sectional view of a back-contact battery provided in an embodiment of the present application;

[0068] Figure 9 1 is another schematic cross-sectional view of a back-contact battery provided in an embodiment of the present application;

[0069] Figure 10 1 is another schematic cross-sectional view of a back-contact battery provided in an embodiment of the present application;

[0070] Figure 11 1 is another schematic cross-sectional view of a back-contact battery provided in an embodiment of the present application;

[0071] Figure 12 1 is another schematic cross-sectional view of a back-contact battery provided in an embodiment of the present application;

[0072] Figure 13 1 is another schematic cross-sectional view of a back-contact battery provided in an embodiment of the present application;

[0073] Figure 14 1 is another schematic cross-sectional view of a back-contact battery provided in an embodiment of the present application;

[0074] Figure 15 1 is another schematic cross-sectional view of a back-contact battery provided in an embodiment of the present application;

[0075] Figure 16 1 is another schematic cross-sectional view of a back-contact battery provided in an embodiment of the present application;

[0076] Figure 17 This is another schematic cross-sectional structure diagram of the back-contact battery provided in an embodiment of the present application.

[0077] Description of main component symbols:

[0078] Photovoltaic system 1000, battery assembly 200, back contact battery 100, silicon substrate 10, light-receiving surface 11, backlight surface 12, first region 121, second region 122, insulating region 123, first passivation layer 20, first doped layer 30, first insulating dielectric layer 40, insulating extension section 41, groove 411, second passivation layer 50, passivation extension section 51, second doped layer 60, doped extension section 61, third doped layer 70, first conductive film 80, first conductive extension portion 81, second conductive film 90, second conductive extension portion 91, third conductive extension portion 92, first electrode 110, second electrode 120, metal electrode 130, third conductive film 140, fourth conductive extension portion 141, fifth conductive extension portion 142, second insulating dielectric layer 150, suspended section 151. DETAILED DESCRIPTION

[0079] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application is further described in detail below with reference to 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 are not to be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are merely used to explain the present application and are not intended to limit the present application.

[0080] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "horizontal", "longitudinal", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0081] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the described features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0082] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0083] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0084] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art will appreciate the application of other processes and / or the use scenarios of other materials.

[0085] 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 multiple back-contact batteries 100 in the embodiment of the present application.

[0086] In an embodiment of the present application, multiple back-contact cells 100 in a battery assembly 200 can be connected in series to form multiple battery strings. Each battery string can be connected in series, in parallel, or in a combination of series and parallel to achieve current bus output. For example, the connection between each battery cell can be achieved by welding a welding ribbon, or the connection between each battery string can be achieved by using a bus bar. In some embodiments, each battery string can be formed into a battery cell array, which is then packaged together with a front plate, a front adhesive film, a rear adhesive film, and a back plate to form a battery assembly 200.

[0087] 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 layer 20 , a first doping layer 30 , a first insulating dielectric layer 40 , a second passivation layer 50 , and a second doping layer 60 .

[0088] The silicon substrate 10 has a light-receiving surface 11 and a backlight surface 12 opposite to each other. Figure 3 As shown, the backlight surface 12 may include a plurality of first areas 121 and a plurality of second areas 122, and the plurality of first areas 121 and the plurality of second areas 122 are alternately arranged along the first direction. The backlight surface 12 also includes an insulating area 123 located between the first areas 121 and the second areas 122, that is, there is an insulating area 123 between adjacent first areas 121 and second areas 122, and the two are separated by the insulating area 123. The first areas 121, the second areas 122 and the insulating area 123 all extend along the second direction, and the second direction intersects with the first direction.

[0089] Specifically, if Figure 3 As shown, the first regions 121 and the second regions 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 cell 100, and the second direction may be the longitudinal direction of the back-contact cell 100, with the two directions being perpendicular to each other. Of course, in other embodiments, the first direction and the second direction may also be other directions, for example, both may be diagonal directions of the silicon substrate 10, and this is not limited here.

[0090] like Figure 4 and Figure 5 As shown, the first passivation layer 20 and the first doping layer 30 are stacked in sequence on the first area 121, that is, along the thickness direction of the back contact battery 100, the first passivation layer 20 and the first doping layer 30 are stacked in sequence on the first area 121, and the first passivation layer 20 and the first doping layer 30 can both completely cover the first area 121, and each first area 121 is provided with a first passivation layer 20 and a first doping layer 30.

[0091] The first insulating dielectric layer 40 is stacked on the insulating region 123 . The first insulating dielectric layer 40 has an insulating extension segment 41 extending and stacked on the first doping layer 30 . The insulating extension segment 41 covers at least a portion of the first doping layer 30 .

[0092] The second passivation layer 50 and the second doping layer 60 are sequentially stacked on the second area 122, that is, along the thickness direction of the back contact battery 100, the second passivation layer 50 and the second doping layer 60 are sequentially stacked on the second area 122, and the second doping layer 60 has an opposite polarity to the first doping layer 30. The second passivation layer 50 and the second doping layer 60 both completely cover the second area 122, and each second area 122 is provided with a second passivation layer 50 and a second doping layer 60.

[0093] The second passivation layer 50 includes a passivation extension 51 extending and stacked on the insulating region 123, and the second doped layer 60 includes a doped extension 61 extending and stacked on the passivation extension 51. The passivation extension 51 and the doped extension 51 only cover the portion of the first insulating dielectric layer 40 corresponding to the insulating region 123. That is, the passivation extension 51 and the doped extension 61 correspond one-to-one, and both extend and cover only the portion of the first insulating dielectric layer 40 corresponding to the insulating region 123.

[0094] In this article, the portion of a certain film layer corresponding to a certain region or a certain layer structure refers to the portion of the film layer that overlaps with the region or other layer structure in the thickness direction. For example, the portion of the first insulating dielectric layer 40 corresponding to the insulating region 123 refers to the portion of the first insulating dielectric layer 40 that covers the second region 122. If there is a similar description below, please refer to this for understanding.

[0095] In the back-contact cell 100, cell assembly 200 and photovoltaic system 1000 in the embodiments of the present application, an insulating region 123 is provided between the first region 121 and the second region 122 of the backlight surface 12, the first passivation layer 20 and the first doping layer 30 are provided in the first region 121, the second passivation layer 50 and the second doping layer 60 are provided in the second region 122, a first insulating dielectric layer 40 is provided on the insulating region 123, the first insulating dielectric layer 40 has an insulating extension segment 41 extending onto the first doping layer 30, the passivation extension segment 51 of the second passivation layer 50 and the doping extension segment 61 of the second doping layer 60 only cover the portion of the first insulating dielectric layer 40 corresponding to the insulating region 123, and do not extend onto the first doping layer 30. In this way, by setting the insulating region 123 and the first insulating dielectric layer 40, the first doped layer 30 and the second doped layer 60 can be insulated and isolated, and the electrical isolation effect between the two can be improved. Moreover, during the manufacturing process, the passivation extension section 51 of the second passivation layer 50 and the doped extension section 61 of the second doped layer 60 can only extend to cover the insulating region 123, and will not cover the first doped layer 30, forming a stacked structure in which two passivation contact structures of different polarities are stacked together in the first region 121, thereby reducing the risk of short circuit leakage and improving the performance of the back contact battery 100.

[0096] Furthermore, the provision of the first insulating dielectric layer 40 and the insulating extension 41 can enhance the surface passivation effect on the side and back surfaces of the insulating region 123 and the first doped layer 30, reducing surface recombination and improving the efficiency of the back-contact cell 100. Furthermore, the provision of the passivation extension 51 and the doped extension 61 can also enhance the hydrogen passivation effect of the insulating region 123.

[0097] Specifically, in the embodiments of the present application, the silicon substrate 10 may be an N-type silicon substrate or a P-type silicon substrate, without limitation. The first doped layer 30 may be an N-type doped layer, and the second doped layer 60 may be a P-type doped layer, or the first doped layer 30 may be a P-type doped layer, and the second doped layer 60 may be a P-type doped layer, without limitation, as long as the polarities of the two layers are opposite.

[0098] In an embodiment of the present application, the back contact cell 100 may be a hybrid back contact cell, wherein the first passivation layer 20 and the first doping layer 30 constitute a first passivation contact structure, and the second passivation layer 50 and the second doping layer 60 constitute a second passivation contact structure, and the types of the passivation contact structures of the two are different. For example, in some embodiments, the first passivation contact structure may be a tunneling passivation contact structure, and the second passivation contact structure may be a heterojunction passivation contact structure. Specifically, in such a back contact cell 100, the first doping layer 30 may be a doped polysilicon layer, and the first passivation layer 20 may be a tunneling oxide layer, for example, a tunneling silicon oxide layer. The second passivation layer 50 may be at least one of an intrinsic amorphous silicon layer or a tunneling oxide layer (for example, a tunneling silicon oxide layer), and the second doping layer 60 may be at least one of a doped amorphous silicon layer and a doped microcrystalline silicon layer.

[0099] In this way, by designing the first doping layer 30 as a doped polysilicon layer and designing the second doping layer 60 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.

[0100] In a preferred embodiment, the first passivation layer 20 is a tunneling oxide layer, the first doped layer 30 is an N-type doped polycrystalline silicon layer, the second passivation layer 50 is an intrinsic amorphous silicon layer, and the second doped layer 60 is a P-type doped amorphous silicon layer or a P-type doped microcrystalline silicon layer. Thus, the first passivation layer 20 and the first doped layer 30 are configured as a tunneling passivation contact structure, and the second passivation layer 50 and the second doped layer 60 are configured as a heterojunction passivation contact structure. Compared to a case where the second passivation layer 50 is a tunneling passivation layer and the second doped layer 60 is a doped polycrystalline silicon layer or a doped microcrystalline silicon layer, this can reduce the recombination rate of carriers and improve the conversion efficiency of the back-contact cell 100.

[0101] In the embodiment of the present application, the first insulating dielectric 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.

[0102] In some embodiments, the first insulating dielectric layer 40 may be at least one of an aluminum oxide film layer, a silicon nitride film layer, a silicon oxide film layer, a silicon oxynitride film layer, a silicon carbide film layer, and a phosphorus oxide film layer, or a combination thereof.

[0103] In some embodiments, the first insulating dielectric layer 40 may be a single-layer structure composed of an aluminum oxide film layer or a silicon nitride film layer. In some embodiments, the first insulating dielectric layer 40 may also be a double-layer 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 backlight 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 backlight surface 12.

[0104] See also Figure 6 In some embodiments, the back contact cell 100 may further include a third doping layer 70 stacked and covering the insulating extension segment 41 , wherein the doping type of the third doping layer 70 is the same as the doping type of the second doping layer 60 , and the third doping layer 70 is insulated from the second doping layer 60 .

[0105] In this way, by disposing the third doped layer 70 on the insulating extension segment 41 , the hydrogen passivation effect of the first region 121 can be effectively enhanced.

[0106] Specifically, in such an embodiment, during the manufacturing process, the second doping layer 60 and the third doping layer 70 can be formed by etching and grooving on an integral doping layer. For example, in some embodiments, after preparing the first doping layer 30 and the first insulating dielectric layer 40, a passivation layer and a doping layer can be deposited as a whole, and then etched to form a second doping layer 60 having a passivation extension segment 51 and a doping extension segment 61 on the insulating region 123 and a third doping layer 70 covering only the insulating extension segment 41. In this way, through the setting of the insulating region 123, the etching groove position can be set at the insulating region 123 to avoid the second doping layer 60 and the first doping layer 30 from stacking in the thickness direction, thereby reducing the risk of leakage.

[0107] Of course, it is understandable that in some embodiments, the third doping layer 70 may not be provided in the back contact battery 100, that is, during the etching process, the insulating extension section 41 and the doping layer on the first doping layer 30 may also be completely etched away, and no specific limitation is made here.

[0108] See also Figure 4 In some embodiments, the passivation extension 51 and the doped extension 61 may preferably only cover a portion of the first insulating dielectric layer 40 corresponding to the insulating region 123 .

[0109] In this way, the passivation extension section 51 and the doped extension section 61 will not be too close to the first region 121 , thereby improving the electrical isolation effect.

[0110] Please continue reading Figure 4In some embodiments, a length D1 of the insulating region 123 in the first direction is 10 μm-600 μm, that is, 10 μm≤D1≤600 μm.

[0111] Thus, by setting the length of the insulating region 123 in the first direction within this reasonable range, it is possible to effectively prevent the insulating region 123 from being too short in the first direction, thereby preventing poor electrical isolation. This can also reduce the difficulty in manufacturing the passivation extension 51 and the doped extension 61, thereby preventing the passivation extension 51 and the doped extension 61 from extending onto the first doped layer 30 during the manufacturing process. Furthermore, it can also prevent the insulating region 123 from being too long in the first direction, thereby preventing the area on the entire backlight surface 12 where the first doped layer 30 and the second doped layer 60 are not provided from being too large, thereby affecting the efficiency of the back-contact cell 100.

[0112] In addition, the setting of the insulating region 123 can improve the bifaciality of the back-contact battery 100. By setting the length of the insulating region 123 within this reasonable range, the relationship between the efficiency and the bifaciality of the back-contact battery 100 can be balanced, and the relationship between the efficiency and the bifaciality can be optimized, thereby improving the bifaciality of the back-contact battery 100 while ensuring the efficiency of the back-contact battery 100.

[0113] It is understood that in the embodiments of the present application, during the etching process (e.g., laser etching), due to the size limitation of the laser spot, if the length of the insulating region 123 is too small, for example, the length of the insulating region 123 is smaller than the size of the laser spot, if the edge of the laser spot is to the left, it is easy to also remove a portion of the second passivation layer 50 and the second doped layer 60 on the second region 122, thereby damaging the silicon substrate 10 and preventing the formation of the passivation extension section 51 and the doped extension section 61. If the edge of the laser spot is to the right, it is easy for the passivation extension section 51 and the doped extension section 61 to extend onto the insulating extension section 41, thereby forming a stacked structure with the first doped layer 30 in the thickness direction. If the length of the insulating region 123 is too large, although the bifaciality will be greatly improved, it will cause a significant decrease in the efficiency of the back contact cell 100.

[0114] That is to say, in the embodiment of the present application, through such a setting, the relationship between the efficiency and bifaciality of the back contact battery 100 can be balanced while the electrical isolation effect is improved to reduce the risk of leakage. While ensuring the electrical isolation effect to reduce the risk of leakage, the efficiency and bifaciality of the back contact battery 100 can achieve a better matching effect.

[0115] Specifically, in such an embodiment, the length of the insulating region 123 in the first direction may be, for example, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm or any value between 10μm-600μm.

[0116] Furthermore, in such an embodiment, after repeated research and demonstration by the inventors, it was found that in order to achieve the optimal matching effect between the efficiency and bifaciality of the back-contact battery 100, the length D1 of the insulating region 123 in the first direction may preferably be 10μm-300μm, for example, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 150μm, 200μm, 250μm, 300μm.

[0117] In some embodiments, the ratio of the length of the passivation extension 51 and the doped extension 61 in the first direction to the length of the insulating region 123 in the first direction is 3%-50%, that is, the ratio of D2 to D1 is 3%-50%.

[0118] In this way, by setting the length ratio between the passivation extension section 51 and the doped extension section 61 and the insulating region 123 within this reasonable range, the hydrogen passivation effect of the insulating region 123 can be improved while ensuring that the distance between the first doped layer 30 and the second doped layer 60 is within a reasonable range, thereby improving the electrical isolation performance.

[0119] Specifically, the ratio between the length of the passivation extension section 51 and the doped extension section 61 in the first direction and the length of the insulating region 123 in the first direction may be, for example, 3%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50% or any value between 3% and 50%.

[0120] See also Figure 4 In some embodiments, the insulating extension segment 41 may only cover a portion of the first doped layer 30. This facilitates the subsequent preparation of the first conductive film 80 and the first electrode 120 described below.

[0121] Of course, see Figure 5In some embodiments, the insulating extension 41 may also cover the entire first doped layer 30. This design can further enhance the hydrogen passivation effect of the first region 121. At the same time, the insulating extension 41 can protect the entire first doped layer 30, preventing wear and scratches on the first doped layer 30 during subsequent processes, and preventing contamination of the surface of the first doped layer 30.

[0122] See also Figure 4-Figure 6 In some embodiments, the back-contact battery 100 may further include a first conductive film 80 and a second conductive film 90. The first conductive film 80 is arranged on at least a portion of the first region 121 and is in conductive contact with the first doping layer 30. The second conductive film 90 is formed on at least a portion of the second doping layer 60 and is in conductive contact with the second doping layer 60. The first conductive film 80 and the second conductive film 90 are insulated from each other.

[0123] In this way, by disposing the first conductive film 80 and the second conductive film 90 , current extraction of the back-contact battery 100 can be achieved.

[0124] Specifically, in the embodiments of the present application, both the first conductive film 80 and the second conductive film 90 are preferably transparent conductive film layers, such as TCO film layers, which can improve the bifaciality of the back-contact cell 100 while achieving current collection. In other embodiments, where bifaciality is not a consideration, the conductive film layer may also be a metal film layer, such as at least one of an aluminum layer, a nickel layer, a copper layer, a silver layer, or a metal alloy layer. Of course, in some embodiments, the conductive film layer may also be a dual-layer structure consisting of a transparent conductive film layer and a metal film layer, which is not specifically limited herein.

[0125] It should be noted that, in such an embodiment, electrodes may be provided on the first conductive film 80 and the second conductive film 90, for example, Figure 4-Figure 6 As shown, first electrodes 120 and second electrodes 110 can be formed on the first conductive film 80 and the second conductive film 90 respectively by electroplating for component welding. The first electrodes 120 and the second electrodes 110 can be, for example, metal electrodes such as copper electrodes. Of course, in some embodiments, it is not necessary to form additional electrodes on the first conductive film 80 and the second conductive film 90, and welding can be performed directly through the first conductive film 80 and the second conductive film 90.

[0126] See also Figure 4 In some embodiments, the insulating extension segment 41 may only cover a portion of the first doping layer 30 , and the first conductive film 80 is formed on at least a portion of the first doping layer 30 that is not covered by the insulating extension segment 41 .

[0127] In this way, the insulating extension segment 41 is set to cover only a portion of the first doped layer 30, and the first conductive film 80 can be directly prepared on the area of ​​the first doped layer 30 not covered by the insulating extension segment 41 to achieve conductive contact between the two, which is relatively simple to prepare.

[0128] Of course, see Figure 5 In some embodiments, the insulating extension segment 41 may also cover the entire first doped layer 30. In this case, a groove 411 is formed on the insulating extension segment 41, and a portion of the first doped layer 30 is exposed from the groove 411. The first conductive film 80 is at least arranged on the portion of the first doped layer 30 exposed from the groove 411 to form a conductive contact with the first doped layer 30.

[0129] In this way, by opening a groove 411 on the insulating extension section 41 and forming a first conductive film 80 at the groove 411, conductive contact between the first conductive film 80 and the first doped layer 30 can also be achieved. At the same time, the first doped layer 30 can be protected by full coverage of the insulating extension section 41 to avoid wear, scratches and dirt on the first doped layer 30.

[0130] Specifically, in such an embodiment, the insulating extension section 41 can cover the entire first doped layer 30, and then, a groove 411 is formed on the insulating extension section 41 by etching an opening (for example, laser drilling, solution etching, etc.) to expose a portion of the first doped layer 30, and then a first conductive film 80 is prepared at the groove 411. The first conductive film 80 can be located only in the groove 411, or can be partially located in the groove 411 and partially extend to the insulating extension section 41 outside the groove 411. There is no specific limitation here.

[0131] Of course, it is understandable that Figure 6 As shown, when the insulating extension segment 41 covers the entire first doped layer 30 and a third doped layer 70 is further provided on the insulating extension segment 41 , the groove 411 also penetrates the third doped layer 70 .

[0132] In the embodiment of the present application, in order to simplify the manufacturing process, the insulating extension section 41 may be preferably configured to cover only a portion of the first doped layer 30 . In this way, the groove forming process on the insulating extension section 41 may be omitted, thereby reducing the manufacturing cost.

[0133] See also Figure 4In some embodiments, the first conductive film 80 and the second conductive film 90 can both be transparent conductive films, the first area 121 can be a polished area (i.e., the surface of the first area 121 is a polished surface), and the second area 122 can be a velvet area (i.e., the surface of the second area 122 is velvet), and the thickness H1 of the portion of the second conductive film 90 corresponding to the second area 122 is less than the thickness H2 of the portion of the first conductive film 80 corresponding to the first area 121, that is, H1<H2.

[0134] In this way, on the one hand, setting the second area 122 of the backlight surface 12 as a suede area can further reduce the reflectivity of the back light, thereby improving the double-sidedness. On the other hand, setting the thickness of the second conductive film 90 located on the upper part of the suede area to be smaller than the thickness of the first conductive film 80 located on the polished area can reduce parasitic absorption in the suede area when the back light enters, thereby further improving the double-sidedness of the back contact battery 100.

[0135] In addition, in such an embodiment, when the first doped layer 30 is doped polycrystalline silicon and the second doped layer 60 is doped amorphous silicon and / or doped microcrystalline silicon, the area corresponding to the doped polycrystalline silicon is set as a 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 doped microcrystalline silicon is better. Setting the area corresponding to the doped amorphous silicon and / or doped microcrystalline silicon as a velvet surface can improve the anti-reflection effect of the back side 12, setting the thickness of the part of the second conductive film 90 located in the velvet area to be thinner can reduce parasitics, thereby improving the double-sidedness of the back contact battery 100, and setting the thickness of the part of the first conductive film 80 corresponding to the first area 121 to be thicker can further improve the passivation effect of the first area 121.

[0136] In some embodiments, the thickness H1 of the portion of the second conductive film 90 corresponding to the second region 122 may be 50nm-90nm, that is, 50nm≤H1≤90nm, and the thickness H2 of the portion of the first conductive film 80 corresponding to the first region 121 may be 75nm-150nm, that is, 75nm≤H2≤150nm.

[0137] Thus, on the one hand, by setting the thickness of the portion of the second conductive film 90 corresponding to the second region 122 within this reasonable range, it is possible to avoid the portion of the second conductive film 90 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 conductive film 90 corresponding to the second region 122 being too thin, which would result in poor passivation effect on the second doped layer 60, and to avoid the portion of the second conductive film 90 corresponding to the second region 122 being too thin, which would result in excessive difficulty in manufacturing, and to avoid the portion of the first conductive film 80 corresponding to the first region 121 being too thin, which would result in poor passivation effect on the first doped layer 30, and to avoid the portion of the first conductive film 80 corresponding to the first region 121 being too thin, which would result in excessive difficulty in manufacturing ... cost.

[0138] In other words, setting the thickness of the two within the above reasonable range can reduce the process difficulty, ensure the passivation effect, control the cost, reduce the parasitic absorption on the back side and improve the double-sidedness.

[0139] Specifically, in such an embodiment, the thickness H1 of the portion of the second conductive film 90 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, and is not limited here.

[0140] The thickness H2 of the portion of the first conductive film 80 corresponding to the first region 121 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, and is not limited here.

[0141] In some embodiments, the ratio of the thickness H2 of the first conductive film 80 corresponding to the first region 121 to the thickness H1 of the second conductive film 90 corresponding to the second region 122 is 1.1-1.8, that is, the ratio of H2 to H1 is 1.1-1.8.

[0142] Thus, by setting the ratio between the thickness of the first conductive film 80 corresponding to the first region 121 and the thickness of the second conductive film 90 corresponding to the second region 122 within this reasonable range, the parasitic absorption and passivation effects on the back side can be better matched.

[0143] 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 1.1-1.8, and is not limited here.

[0144] See also Figure 7 In some embodiments, the insulating region 123 is a velvet region (i.e., the surface of the insulating region 123 is velvet), and the first conductive film 80 has a first conductive extension portion 81. The first conductive extension portion 81 extends to the portion of the first insulating medium layer 40 corresponding to the insulating region 123 and is insulated from the doped extension segment 61. The thickness H3 of the first conductive extension portion 81 is less than the thickness H2 of the portion of the first conductive film 80 corresponding to the first region 121, that is, H3<H2.

[0145] Thus, on the one hand, configuring the insulating region 123 of the backlight surface 12 as a textured region can further reduce the reflectivity of the backlight light, thereby further improving the bifaciality. On the other hand, the provision of the first conductive extension 81 can enhance the hydrogen passivation effect of the insulating region 123. Furthermore, by reducing the thickness of the first conductive extension 81 located above the insulating region 123 in the first conductive film 80, the parasitic absorption of light in the insulating region 123 can be reduced, further improving the bifaciality of the back-contact cell 100.

[0146] In some embodiments, the thickness H3 of the first conductive extension 81 may be 40 nm-80 nm, and the thickness H2 of the portion of the first conductive film 80 corresponding to the first region 121 may be 75 nm-150 nm.

[0147] Thus, on the one hand, by setting the thickness of the first conductive extension 81 within a reasonable range of 40nm-80nm, it is possible to avoid the first conductive extension 81 being too thin, which would result in poor passivation effect on the insulating region 123, while also avoiding excessive parasitic absorption and increased costs due to excessive thickness. On the other hand, by setting the thickness of the portion of the first conductive film 80 corresponding to the first region 121 within a reasonable range of 75nm-150nm, it is possible to avoid the portion of the first conductive film 80 corresponding to the first region 121 being too thin, which would result in excessive manufacturing difficulty, and also avoid the portion of the first conductive film 80 corresponding to the first region 121 being too thin, which would result in poor passivation effect on the first doped layer 30, while also avoiding excessive parasitic absorption and increased costs due to excessive thickness.

[0148] Specifically, in such an embodiment, the thickness H3 of the first conductive extension portion 81 may be, for example, 40nm, 42nm, 44nm, 46nm, 48nm, 50nm, 52nm, 54nm, 56nm, 58nm, 60nm, 62nm, 64nm, 66nm, 68nm, 70nm, 72nm, 74nm, 76nm, 78nm, 80nm or any value between 40nm-80nm, and there is no specific limitation here.

[0149] The thickness H2 of the portion of the first conductive film 80 corresponding to the first region 121 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, and is not limited here.

[0150] In some embodiments, the ratio of the thickness H2 of the portion of the first conductive film 80 corresponding to the first region 121 to the thickness H3 of the first conductive extension 81 is 1.3-2, that is, the ratio of H2 to H3 is 1.3-2.

[0151] Thus, by setting the ratio between the thickness of the portion of the first conductive film 80 corresponding to the first region 121 and the thickness of the first conductive extension 81 within this reasonable range, the parasitic absorption and passivation effects on the back surface can be better matched.

[0152] Specifically, in such an embodiment, the ratio between the two may be, for example, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2 or any value between 1.3 and 2, and is not limited here.

[0153] See also Figure 7 In some embodiments, the insulating region 123 and the second region 122 are both velvet regions (i.e., the surfaces of the insulating region 123 and the second region 122 are not velvet), and the surface roughness of the second region 122 is less than the surface roughness of the insulating region 123, and the thickness H3 of the first conductive extension portion 81 is less than the thickness H1 of the portion of the second conductive film 90 corresponding to the second region 122, that is, H3

[0154] Such a configuration can further reduce the parasitic absorption of light in the insulating region 123 and improve the bifaciality.

[0155] See also Figure 8 ​In some embodiments, the insulating region 123 and the second region 122 are both velvet regions (i.e., the surfaces of the insulating region 123 and the second region 122 are not velvet), the surface roughness of the second region 122 is less than the surface roughness of the insulating region 123, and the second conductive film 90 has a second conductive extension portion 91 extending to the doped extension segment 61, and the thickness H4 of the second conductive extension portion 91 is less than the thickness H1 of the portion of the second conductive film 90 corresponding to the second region 122, i.e., H4

[0156] In this way, on the one hand, the setting of the second conductive extension portion 91 can further enhance the hydrogen passivation effect of the insulating region 123. On the other hand, setting both the insulating region 123 and the second region 122 as suede regions can reduce the reflectivity of the back light and improve the double-sidedness. Setting the thickness of the second conductive extension portion 91 located on the insulating region 123 in the second conductive film 90 to be smaller than the thickness of the portion corresponding to the second conductive film 90 and the second region 122 can further reduce the parasitic absorption of light in the insulating region 123, further improve the double-sidedness, and also improve the passivation effect of the second region 122.

[0157] Furthermore, in such an embodiment, the thickness H4 of the second conductive extension 91 may be 40 nm-80 nm, and the thickness H1 of the portion of the second conductive film 90 corresponding to the second region 122 may be 50 nm-90 nm.

[0158] In this way, by setting the thicknesses of the two regions within the above ranges, the bifaciality of the back contact cell 100 can be effectively improved while ensuring the passivation effect of the second region 122 and the insulating region 123 .

[0159] Specifically, in such an embodiment, the thickness of the second conductive extension 91 may be, for example, 40 nm, 42 nm, 44 nm, 46 nm, 48 nm, 50 nm, 52 nm, 54 nm, 56 nm, 58 nm, 60 nm, 62 nm, 64 nm, 66 nm, 68 nm, 70 nm, 72 nm, 74 nm, 76 nm, 78 nm, 80 nm, or any value between 40 nm and 80 nm, without limitation thereto. The thickness H1 of the portion of the second conductive film 90 corresponding to the second region 122 may be, for example, 50 nm, 52 nm, 54 nm, 56 nm, 58 nm, 60 nm, 62 nm, 64 nm, 66 nm, 68 nm, 70 nm, 72 nm, 74 nm, 76 nm, 78 nm, 80 nm, 82 nm, 84 nm, 86 nm, 88 nm, 90 nm, or any value between 50 nm and 90 nm, without limitation thereto.

[0160] ​Furthermore, in some embodiments, the ratio between the thickness H1 of the portion of the second conductive film 90 corresponding to the insulating region 123 and the thickness H4 of the second conductive extension 91 is 1.1-2, that is, the ratio of H1 to H4 is 1.1-2.

[0161] Thus, by setting the ratio between the thickness H1 of the portion of the second conductive film 90 corresponding to the insulating region 123 and the thickness H4 of the second conductive extension 91 within this reasonable range, the parasitic absorption and passivation effects on the back surface can be better matched.

[0162] 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, 1.85, 1.9, 1.95, or any value between 1.1-2, and is not limited thereto.

[0163] In some embodiments, when the back-contact cell 100 includes both the first conductive extension 81 and the second conductive extension 91 , the thickness of the second conductive extension 91 may be the same as that of the first conductive extension 81 , that is, H3 = H4 .

[0164] See also Figure 9 In some embodiments, the second conductive film 90 may further include a third conductive extension 92 extending onto the insulating extension segment 41. The thickness H5 of the third conductive extension 92 is greater than the thickness H4 of the second conductive extension 91 and also greater than the thickness H1 of the portion of the second conductive film 90 corresponding to the second region 122. That is, in such an embodiment, H4

[0165] Thus, when the first doped layer 30 is a doped polysilicon layer and the second doped layer 60 is a doped amorphous silicon layer or a doped microcrystalline silicon layer, the thickness of the third conductive extension portion 92 located on the first region 121 is set to be thicker, which can further enhance the hydrogen passivation effect in the first region 121 .

[0166] Furthermore, in such an embodiment, the thickness H5 of the third conductive extension 92 can be the same as the thickness H2 of the portion of the first conductive film 80 corresponding to the first region 121, that is, H5 = H2. This can enhance the passivation effect of the first region 121. The specific thicknesses of the two are as described above and are not further elaborated here.

[0167] See also Figure 10 and Figure 11 ​In some embodiments, the back-contact battery 100 may include a metal electrode 130 and a third conductive film 140, wherein the metal electrode 130 is arranged on the first region 121 and is in conductive contact with the first doped layer 30, and the third conductive film 140 is formed on at least a portion of the second doped layer 60 and is in conductive contact with the second doped layer 60, and the third conductive film 140 is insulated from the metal electrode 130.

[0168] Among them, Figure 10 As shown, in some embodiments, the insulating extension segment 41 may only cover a portion of the first doped layer 30, and the metal electrode 130 is disposed on the portion of the first doped layer 30 not covered by the insulating extension segment 41; or as shown in FIG. Figure 11 As shown, in some embodiments, the insulating extension segment 41 may also cover the entire first doped layer 30 , and the metal electrode 130 is disposed on the insulating extension segment 41 and passes through the insulating extension segment 41 to be in conductive contact with the first doped layer 30 .

[0169] In this way, current output can be achieved by directly disposing the metal electrode 130 on the first doped layer 30, without the need to deposit a conductive film layer such as TCO by deposition or other methods and then prepare an electrode on the conductive film, which can simplify the manufacturing process.

[0170] Specifically, in this embodiment, the first passivation layer 20 is a tunneling oxide layer, the first doped layer 30 is a doped polysilicon layer, the second passivation layer 50 can be an intrinsic amorphous silicon layer or a tunneling oxide layer, and the second doped layer 60 is a doped amorphous silicon layer or a doped microcrystalline silicon layer. It is readily understood that this embodiment differs from the embodiment having the first conductive film 80 and the second conductive film 90 described above in that the first conductive film 80 is replaced by a metal electrode 130, and the third conductive film 140 is equivalent to the second conductive film 90 described above.

[0171] In addition, it can also be understood that in such an embodiment, the third doped layer 70 ( Figure 10 and Figure 11 In this case, the metal electrode 130 may sequentially penetrate the third doped layer 70 and the insulating extension segment 41 to achieve conductive contact with the first doped layer 30.

[0172] Further, see Figure 12 In such an embodiment, both the second region 122 and the insulating region 123 may be suede regions, the surface roughness of the second region 122 is less than the surface roughness of the insulating region 123, the third conductive film 140 has a fourth conductive extension portion 141 extending at least to the doped extension segment 61, and the thickness H7 of the fourth conductive extension portion 141 is less than the thickness H6 of the portion of the third conductive film 140 corresponding to the second region 122, that is, in Figure 12 In the middle, H7<H6.

[0173] Thus, setting the thickness of the fourth conductive extension portion 141 of the third conductive film 140 located on the insulating region 123 to be smaller than the thickness of the portion of the third conductive film 140 corresponding to the second region 122 can reduce parasitic absorption of light in the insulating region 123 and further improve the bifaciality.

[0174] Furthermore, in such an embodiment, the thickness H7 of the fourth conductive extension portion 141 may be 40 nm-80 nm, and the thickness H6 of the portion of the third conductive film 140 corresponding to the second region 122 may be 50 nm-90 nm.

[0175] In this way, by setting the thicknesses of the two regions within the above ranges, the bifaciality of the back contact cell 100 can be effectively improved while ensuring the passivation effect of the second region 122 and the insulating region 123 .

[0176] Specifically, the thickness H7 of the fourth conductive extension 141 may be, for example, 40 nm, 42 nm, 44 nm, 46 nm, 48 nm, 50 nm, 52 nm, 54 nm, 56 nm, 58 nm, 60 nm, 62 nm, 64 nm, 66 nm, 68 nm, 70 nm, 72 nm, 74 nm, 76 nm, 78 nm, 80 nm, or any value between 40 nm and 80 nm, without limitation thereto. The thickness H6 of the portion of the third conductive film 140 corresponding to the second region 122 may be, for example, 50 nm, 52 nm, 54 nm, 56 nm, 58 nm, 60 nm, 62 nm, 64 nm, 66 nm, 68 nm, 70 nm, 72 nm, 74 nm, 76 nm, 78 nm, 80 nm, 82 nm, 84 nm, 86 nm, 88 nm, 90 nm, or any value between 50 nm and 90 nm, without limitation thereto.

[0177] Furthermore, in some embodiments, the ratio of the thickness H6 of the portion of the third conductive film 140 corresponding to the second region 122 to the thickness H7 of the fourth conductive extension 141 is 1.1-2, that is, the ratio of H6 to H7 is 1.1-2.

[0178] Thus, by setting the ratio between the thickness H6 of the portion of the second conductive film 90 corresponding to the second region 122 and the thickness H7 of the fourth conductive extension 141 within this reasonable range, the parasitic absorption and passivation effects on the back surface can be better matched.

[0179] 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, 1.85, 1.9, 1.95, 2 or any value between 1.1 and 2, and is not limited thereto.

[0180] See also Figure 13 In some embodiments, the third conductive film 140 further has a fifth conductive extension portion 142 extending onto the insulating extension segment 41. The thickness H8 of the fifth conductive extension portion 142 is greater than the thickness H6 of the portion of the third conductive film 140 corresponding to the second region 122 and is greater than the thickness H7 of the fourth conductive extension portion 141, that is, H7<H6<H8.

[0181] Thus, when the first doped layer 30 is a doped polysilicon layer and the second doped layer 60 is a doped amorphous silicon layer or a doped microcrystalline silicon layer, the thickness of the fifth conductive extension portion 142 located on the first region 121 is set to be thicker, which can further enhance the passivation effect at the first region 121 .

[0182] In some embodiments, the fifth conductive extension 142 may have a thickness of 75 nm-150 nm.

[0183] Thus, by setting the thickness of the fifth extension portion 142 within this reasonable range, the passivation effect of the first region 121 can be optimized while controlling the cost.

[0184] Specifically, in such an embodiment, the thickness H8 of the fifth conductive extension 142 can be, for example, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, or any value between 75 nm and 150 nm, without limitation. The thickness of the portion of the third conductive film 140 corresponding to the second region 122 and the thickness of the fourth conductive extension 141 are as described above.

[0185] See also Figure 14 In some embodiments, the first region 121 is a polished region (i.e., the surface of the first region 121 is a polished surface), the second region 122 is a velvet region (i.e., the surface of the second region 122 is a velvet surface), and the thickness H11 of the portion of the first insulating medium layer 40 corresponding to the insulating region 123 is less than the thickness H10 of the insulating extension segment 41.

[0186] In this way, by setting the thickness of the portion of the first insulating dielectric layer 40 corresponding to the insulating region 123 to be smaller, the parasitic absorption of light by the first insulating dielectric layer 40 in the insulating region 123 can be reduced, further improving the double-sidedness. By setting the thickness of the insulating extension section 41 to be larger, the hydrogen passivation effect of the first region 121 can be improved.

[0187] Furthermore, in some embodiments, the thickness H11 of the portion of the first insulating dielectric layer 40 corresponding to the insulating region 123 may be 50 nm-100 nm, and the thickness H10 of the insulating extension segment 41 may be 60 nm-150 nm.

[0188] Thus, by setting the thicknesses of the two regions within the above ranges, the passivation effects of the first region 121 and the insulating region 123 can be effectively improved while the bifaciality of the back contact cell 100 can be effectively improved.

[0189] Specifically, in such an embodiment, the thickness H11 of the portion of the first insulating dielectric layer 40 corresponding to the insulating region 123 may be, for example, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, or any value between 50 nm and 100 nm, without limitation thereto. The thickness H10 of the insulating extension 41 may be, for example, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, or any value between 60 nm and 150 nm, without limitation thereto.

[0190] Furthermore, in some embodiments, a ratio of the thickness H10 of the insulating extension segment 41 to the thickness H11 of the portion of the first insulating dielectric layer 40 corresponding to the insulating region 123 may be 1.1-2.

[0191] Thus, setting the thickness ratio between the two within this reasonable range can improve the passivation effect and double-sidedness while avoiding excessive costs.

[0192] 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, 1.85, 1.9, 1.95, 2 or any value between 1.1 and 2, and is not limited thereto.

[0193] See also Figure 15In some embodiments, a second insulating dielectric layer 150 is provided between the insulating extension segment 41 and the first doped layer 30. The second insulating dielectric layer 150 has a suspended segment 151 extending along the first direction and protruding from the first region 121. The suspended segment 151 is suspended on the insulating region 123, and the first insulating dielectric layer 40 surrounds the suspended segment 151 in the first direction.

[0194] In this way, by further disposing the second insulating dielectric layer 150 between the first insulating dielectric layer 40 and the first doped layer 30 , and the second insulating dielectric layer 150 having the suspended section 151 , the electrical isolation effect of the back contact battery 100 can be further improved.

[0195] At the same time, in the thickness direction of the back contact battery 100, a deposition space is formed between the suspended section 151 and the insulating region 123, so that in the process of subsequent deposition of the first insulating dielectric layer 40, the setting of such a deposition space can suppress the sufficient exchange of plasma in the region with plasma components outside the region, thereby realizing the localized distribution of the mobile hydrogen content in the first insulating dielectric layer 40, so that the mobile hydrogen content of the first insulating dielectric layer 40 in the deposition region is lower, and the mobile hydrogen content of the first insulating dielectric layer 40 in the remaining regions is higher, so as to achieve the best passivation and anti-attenuation effects.

[0196] Specifically, the second insulating dielectric layer 150 may be one or more of silicon oxide, silicon nitride, and silicon oxynitride. In some embodiments, the second insulating dielectric layer 150 may contain the same doping element as the doping element in the first doping layer 30. For example, when the first doping layer 30 is N-type doped polysilicon, the second insulating dielectric layer 150 may be a PSG film layer.

[0197] It is understood that in such an embodiment, when the insulating extension 41 only covers a portion of the first doped layer 30, the second insulating dielectric layer 150 also only covers a portion of the first doped layer 30. When the insulating extension 41 completely covers the entire first doped layer 30, the second insulating dielectric layer 150 also covers the entire first doped layer 30. Furthermore, it is also understood that when the insulating extension 41 completely covers the entire first doped layer 30, the groove 411 described above also penetrates the second insulating dielectric layer 150.

[0198] For further information, please refer to Figure 15 In some embodiments, the thickness of the portion of the first insulating dielectric layer 40 located on the sides of the first passivation layer 20 and the first doping layer 30 gradually decreases in a direction approaching the suspended segment 151 .

[0199] In this way, by designing such a thickness change scheme, the structural stress of the membrane layer can be reduced and the stability of the battery structure can be improved.

[0200] Please continue reading Figure 15 In some embodiments, a portion of the first insulating dielectric layer 40 located on the surface of the suspended segment 151 facing the silicon substrate 10 gradually increases in size in the protruding direction of the suspended segment 151 .

[0201] In this way, by designing such a thickness change scheme, the structural stress of the membrane layer can be alleviated and the stability of the battery structure can be improved.

[0202] Specifically, in such an embodiment, due to the shielding effect of the suspended segment 151, during the process of depositing the first insulating dielectric layer 40, the thickness of the first insulating dielectric layer 40 at the shielding position can undergo the above-mentioned change, and this change improves the stability of the battery structure.

[0203] In some embodiments, the light receiving surface 11 is a suede surface, the insulating region 123 is a suede region, and the surface roughness of the insulating region 123 is smaller than the surface roughness of the light receiving surface 11 .

[0204] In this way, by setting both the insulating area 123 and the light-receiving surface 11 to be velvet and the surface roughness of the insulating area 123 is smaller than the surface roughness of the light-receiving surface 11, the reflectivity of the front light can be reduced to improve the efficiency of the back-contact battery 100 while improving the bifaciality of the back-contact battery 100.

[0205] See also Figure 16 Furthermore, in some embodiments, a third passivation layer 160 may be formed on the light receiving surface 11 , and the thickness of the third passivation layer 160 is less than the thickness of the portion of the first insulating dielectric layer 40 corresponding to the insulating region 123 .

[0206] In this way, by setting the thickness of the third passivation layer 160 on the light-receiving side to be smaller, the parasitic absorption of the front light can be reduced, and the efficiency of the back-contact cell 100 can be further improved.

[0207] Specifically, in such an embodiment, the third passivation layer 160 may be an anti-reflection passivation layer, which may be at least one of a silicon nitride film layer, an aluminum oxide film layer, a silicon oxide film layer, and a silicon oxynitride film layer. The third passivation layer 160 may be a single-layer film structure or a double-layer or multi-layer film structure, and is not specifically limited here.

[0208] In some embodiments, the silicon substrate 10 further has several side surfaces 13 connecting the light-receiving surface 11 and the backlight surface 12 , and at least some of the side surfaces 13 have a fourth passivation layer 170 , the thickness of the fourth passivation layer 170 being greater than the thickness of the first insulating dielectric layer 40 .

[0209] Thus, by providing the fourth passivation layer 170 on the side surface 13 of the silicon substrate 10 and the fourth passivation layer 170 being thicker than the first insulating dielectric layer 40 , the side surface 13 of the silicon substrate 10 can be efficiently passivated, reducing edge recombination, thereby further improving conversion efficiency.

[0210] See also Figure 16 In some embodiments, the first insulating dielectric layer 40 may include a first aluminum oxide film layer. Specifically, the first insulating dielectric layer 40 may include at least one aluminum oxide film layer, which may be a single aluminum oxide film layer or may include other film layers in addition to the aluminum oxide film layer. The specific embodiment is not limited here. The side surfaces 13 of the silicon substrate 10 include at least one cut surface 131. In other words, the back-contact cell 100 is a sliced ​​cell. Among the side surfaces 13 of the silicon substrate 10, at least one is a cut surface. For example, when the back-contact cell 100 is substantially rectangular, at least one of the two side surfaces 13 of the silicon substrate 10 in the first direction is a cut surface 131.

[0211] The cut surface 131 has a second aluminum oxide film layer 171 thereon. That is, on the cut surface 131 , the fourth passivation layer 170 mentioned above includes the second aluminum oxide film layer 171 .

[0212] In this case, the cutting surface 131 includes a first region 1311 connected to the backlight surface 12 and a second region 1312 farther away from the backlight surface 12 than the first region 1311, and the ratio of oxygen elements to aluminum elements in the portion of the second aluminum oxide film layer 171 corresponding to the first region 1311 is greater than the ratio of oxygen elements to aluminum elements in the first aluminum oxide film layer.

[0213] Specifically, the first region 1311 is the cutting area when the cell is cut and is directly affected by external cutting forces. During the cutting process, the first region 1311 of the cut surface 131, which is close to the backlight surface 12, is prone to more defects and larger surface recombination. Therefore, setting a higher ratio of oxygen to aluminum in the portion of the second aluminum oxide film 171 corresponding to the first region 1311 can achieve efficient passivation in this region, reduce recombination, and thus improve the efficiency of the back-contact cell 100.

[0214] Further, in such an embodiment, the ratio of oxygen to aluminum in the portion of the second aluminum oxide film layer 171 corresponding to the first region 1311 is greater than the ratio of oxygen to aluminum in the portion of the second aluminum oxide film layer 171 corresponding to the second region 1312; and, the ratio of oxygen to aluminum in the portion of the second aluminum oxide film layer 171 corresponding to the second region 1312 is greater than the ratio of oxygen to aluminum in the first aluminum oxide film layer.

[0215] Specifically, the second region 1312 is generally not subject to external cutting forces or is subject to relatively small cutting forces during cutting, making it less likely to produce large defects. However, if the oxygen content in this region is too high, it is likely to introduce numerous defects. Therefore, by setting the ratio of oxygen to aluminum in the portion of the second aluminum oxide film 171 corresponding to the second region 1312 to be relatively low, the differential effects of the first region 1311 and the second region 1312 can be balanced, thereby ensuring the efficiency of the back-contact cell 100. Furthermore, by setting the ratio of oxygen to aluminum in the portion of the second aluminum oxide film 171 corresponding to the second region 1312 to be greater than the ratio of oxygen to aluminum in the first aluminum oxide film, the passivation effect of the cut surface 131 can be ensured.

[0216] In some embodiments, the thickness of the portion of the second aluminum oxide film 171 corresponding to the first region 1311 is greater than the thickness of the first aluminum oxide film.

[0217] In this way, the passivation effect at the first region 1311 which is more affected by the cutting force can be enhanced, thereby improving the performance of the back contact battery.

[0218] See also Figure 17 In some embodiments, a fourth region 124 is provided between the first region 121 and / or the second region 122 closest to the edge of the silicon substrate 10 and the edge of the silicon substrate 10 , and a third insulating dielectric layer 180 is provided on the fourth region 124 , and the thickness of the third insulating dielectric layer 180 is greater than the thickness of the first insulating dielectric layer 40 .

[0219] In this way, since the recombination at the edge of the silicon substrate 10 is usually larger, a thicker third insulating dielectric layer 180 is set at a position close to the edge of the silicon substrate 10, which can improve the passivation effect at the edge of the silicon substrate 10, thereby ensuring the efficiency of the back contact battery 100.

[0220] Specifically, Figure 17 It is only shown that there is a third region 124 between the second region 122 closest to the edge of the silicon substrate 10 and the edge of the silicon substrate 10. It can be understood that the silicon substrate 10 has two opposite edges in the first direction, and the areas closest to the two edges can both be the first region 121, or both be the second region 122, or one side can be the first region 121 and the other side can be the second region 122. No specific limitation is made here.

[0221] Furthermore, in some embodiments, as described above, the first insulating dielectric layer 40 may include a first aluminum oxide film layer. The third insulating dielectric layer 180 may include a third aluminum oxide film layer, wherein the ratio of oxygen to aluminum in the third aluminum oxide film layer is greater than the ratio of oxygen to aluminum in the first aluminum oxide film layer.

[0222] In this way, setting the ratio of oxygen and aluminum in the third aluminum oxide film layer on the fourth region 124 located at the edge to be higher can further enhance the passivation effect of the fourth region 124 located at the edge, thereby enhancing the performance of the back contact battery.

[0223] Throughout this specification, reference to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is 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. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0224] 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 replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A back contact battery, characterized in that: include: a silicon substrate having a light-receiving surface and a backlight surface facing each other, the backlight surface comprising a plurality of first regions and a plurality of second regions alternately arranged along a first direction, and the backlight surface further comprising an insulating region between the first regions and the second regions, the insulating region separating the first regions from the second regions, the first regions, the second regions, and the insulating spacer region all extending along a second direction, the second direction intersecting the first direction; sequentially stacking a first passivation layer and a first doping layer on the first region; a first insulating dielectric layer disposed on the insulating region, the first insulating dielectric layer having an insulating extension segment extending and stacked on the first doped layer, the insulating extension segment covering at least a portion of the first doped layer; and A second passivation layer and a second doped layer are sequentially stacked on the second region, wherein the second doped layer has an opposite polarity to the first doped layer, the second passivation layer has a passivation extension segment extending and stacked on the insulating region, and the second doped layer has a doped extension segment extending and stacked on the passivation extension segment, and the passivation extension segment and the doped extension segment only cover the portion of the first insulating medium layer corresponding to the insulating region.

2. The back contact battery according to claim 1, characterized in that The passivation extension segment and the doping extension segment are only disposed on a portion of the first insulating dielectric layer corresponding to the insulating region.

3. The back contact battery according to claim 1, characterized in that The length of the insulating region in the first direction is 10 μm-600 μm.

4. The back contact battery according to claim 3, characterized in that The length of the insulating region in the first direction is 10 μm-300 μm.

5. The back contact battery according to claim 3, characterized in that A ratio between the lengths of the passivation extension and the doped extension in the first direction and the length of the insulating region in the first direction is 3%-50%.

6. The back contact battery according to claim 1, characterized in that The insulating extension covers the entire first doped layer.

7. The back contact battery according to claim 6, characterized in that The back contact cell further includes a third doping layer stacked and covering the insulating extension segment. The doping type of the third doping layer is the same as the doping type of the second doping layer, and the third doping layer is insulated from the second doping layer.

8. The back contact battery according to claim 1, characterized in that The back-contact battery also includes a first conductive film and a second conductive film, the first conductive film is arranged on at least a portion of the first zone and is in conductive contact with the first doped layer, the second conductive film is formed on at least a portion of the second doped layer and is in conductive contact with the second doped layer, and the first conductive film and the second conductive film are insulated from each other.

9. The back contact battery according to claim 8, characterized in that The insulating extension segment only covers a portion of the first doped layer, and the first conductive film is formed on at least a portion of the first doped layer that is not covered by the insulating extension segment; or The insulating extension section covers the entire first doped layer. A groove is formed on the insulating extension section. Part of the first doped layer is exposed from the groove. The first conductive film is at least arranged on the portion of the first doped layer exposed from the groove.

10. The back contact battery according to claim 8, characterized in that The first area is a polished area, the second area is a suede area, the first conductive film and the second conductive film are both transparent conductive films, and the thickness of the second conductive film corresponding to the second area is smaller than the thickness of the first conductive film corresponding to the first area.

11. The back contact battery according to claim 10, characterized in that The thickness of the portion of the second conductive film corresponding to the second region is 50 nm to 90 nm, and the thickness of the portion of the first conductive film corresponding to the first region is 75 nm to 150 nm.

12. The back contact battery according to claim 10, characterized in that A ratio between a thickness of a portion of the first conductive film corresponding to the first region and a thickness of a portion of the second conductive film corresponding to the second region is 1.1-1.

8.

13. The back contact battery according to claim 10, characterized in that The insulating area is a velvet area, the first conductive film has a first conductive extension portion, the first conductive extension portion extends to the portion of the first insulating medium layer corresponding to the insulating area and is insulated from the doped extension segment, and the thickness of the first conductive extension portion is less than the thickness of the portion of the first conductive film corresponding to the first area.

14. The back contact battery according to claim 13, characterized in that The thickness of the first conductive extension portion is 40 nm to 80 nm, and the thickness of the portion of the first conductive film corresponding to the first region is 75 nm to 150 nm.

15. The back contact battery according to claim 13, characterized in that A ratio between a thickness of a portion of the first conductive film corresponding to the first region and a thickness of the first conductive extension portion is 1.3-2.

16. The back contact battery according to claim 10, characterized in that The insulating region is velvet-finished, the surface roughness of the second region is smaller than the surface roughness of the insulating region, the second conductive film has a second conductive extension portion extending onto the doped extension segment, and the thickness of the second conductive extension portion is smaller than the thickness of the portion of the second conductive film corresponding to the second region.

17. The back contact battery according to claim 16, characterized in that The thickness of the second conductive extension portion is 40 nm to 80 nm, and the thickness of the portion of the second conductive film corresponding to the second region is 50 nm to 90 nm.

18. The back contact battery according to claim 16, characterized in that The ratio between the thickness of the portion of the second conductive film corresponding to the second region and the thickness of the second conductive extension is 1.1-2.

19. The back contact battery according to claim 16, characterized in that The second conductive film further has a third conductive extension portion extending onto the insulating extension segment. The thickness of the third conductive extension portion is greater than that of the second conductive extension portion and also greater than that of a portion of the second conductive film corresponding to the second region.

20. The back contact cell according to claim 19, characterized in that The thickness of the third conductive extension portion is the same as the thickness of a portion of the first conductive film corresponding to the first region.

21. The back contact cell according to claim 1, characterized in that The back-contact battery comprises a metal electrode and a third conductive film, wherein the metal electrode is disposed on the first region and is in conductive contact with the first doped layer, the third conductive film is formed on at least a portion of the second doped layer and is in conductive contact with the second doped layer, and the third conductive film is insulated from the metal electrode; The insulating extension section only covers a portion of the first doped layer, and the metal electrode is provided on a portion of the first doped layer not covered by the insulating extension section; or The insulating extension segment covers the entire first doped layer. The metal electrode is disposed on the insulating extension segment and passes through the insulating extension segment to be in conductive contact with the first doped layer.

22. The back contact cell according to claim 21, characterized in that The second region and the insulating region are both velvet regions, the surface roughness of the second region is smaller than the surface roughness of the insulating region, the third conductive film has a fourth conductive extension portion extending at least to the doped extension segment, and the thickness of the fourth conductive extension portion is smaller than the thickness of the portion of the third conductive film corresponding to the second region.

23. The back contact cell according to claim 22, characterized in that The thickness of the fourth conductive extension portion is 40 nm to 80 nm, and the thickness of the portion of the third conductive film corresponding to the second region is 50 nm to 90 nm.

24. The back contact cell according to claim 22, characterized in that The ratio between the thickness of the portion of the third conductive film corresponding to the second region and the thickness of the fourth conductive extension portion is 1.1-2.

25. The back contact battery according to any one of claims 22 to 24, characterized in that The third conductive film further has a fifth conductive extension portion extending onto the insulating extension segment. The thickness of the fifth conductive extension portion is greater than the thickness of a portion of the third conductive film corresponding to the second region and greater than the thickness of the fourth conductive extension portion.

26. The back contact cell according to claim 25, characterized in that The thickness of the fifth conductive extension portion is 75 nm-150 nm.

27. The back contact cell according to claim 1, characterized in that The first area is a polished area, the insulating area is a suede area, and the thickness of a portion of the first insulating medium layer corresponding to the insulating area is smaller than the thickness of the insulating extension section.

28. The back contact cell according to claim 1, characterized in that The thickness of the portion of the first insulating dielectric layer corresponding to the insulating region may be 50 nm-100 nm, and the thickness of the insulating extension segment may be 60 nm-150 nm.

29. The back contact cell according to claim 1, characterized in that The ratio of the thickness of the insulating extension segment to the thickness of the portion of the first insulating dielectric layer corresponding to the insulating region is 1.1-2.

30. The back contact battery according to claim 1, characterized in that A second insulating dielectric layer is provided between the insulating extension section and the first doped layer. The second insulating dielectric layer has a suspended section extending along the first direction and protruding from the first region. The suspended section is suspended on the insulating region. The first insulating dielectric layer surrounds the suspended section in the first direction.

31. The back contact cell according to claim 30, characterized in that The thickness of a portion of the first insulating dielectric layer located on the sides of the first passivation layer and the first doping layer gradually decreases in a direction approaching the suspended segment.

32. The back contact cell according to claim 30, characterized in that A portion of the first insulating dielectric layer located on the surface of the suspended segment facing the silicon substrate gradually increases in size in a protruding direction of the suspended segment.

33. The back contact cell according to claim 1, characterized in that The light-receiving surface is a velvet surface, the insulating area is a velvet area, and the surface roughness of the insulating area is smaller than the surface roughness of the light-receiving surface.

34. The back contact cell according to claim 33, characterized in that A third passivation layer is formed on the light-receiving surface, and a thickness of the third passivation layer is smaller than a thickness of a portion of the first insulating dielectric layer corresponding to the insulating region.

35. The back contact cell according to claim 1, characterized in that The silicon substrate further has a plurality of side surfaces connecting the light-receiving surface and the backlight surface, at least some of the side surfaces have a fourth passivation layer, and the thickness of the fourth passivation layer is greater than the thickness of the first insulating dielectric layer.

36. The back contact cell according to claim 1, characterized in that The first insulating dielectric layer includes a first aluminum oxide film layer; The silicon substrate also has several side surfaces connecting the light-receiving surface and the backlight surface, and the several side surfaces include at least one cutting surface, and the cutting surface has a second aluminum oxide film layer. The cutting surface includes a first area connected to the backlight surface and a second area farther away from the backlight surface than the first area. The ratio of oxygen and aluminum elements in the part of the second aluminum oxide film layer corresponding to the first area is greater than the ratio of oxygen and aluminum elements in the first aluminum oxide film layer.

37. The back contact cell according to claim 36, characterized in that The ratio of oxygen to aluminum elements in the portion of the second aluminum oxide film layer corresponding to the first region is greater than the ratio of oxygen to aluminum elements in the portion of the second aluminum oxide film layer corresponding to the second region; and the ratio of oxygen to aluminum elements in the portion of the second aluminum oxide film layer corresponding to the second region is greater than the ratio of oxygen to aluminum elements in the first aluminum oxide film layer.

38. The back contact cell according to claim 36, characterized in that A thickness of a portion of the second aluminum oxide film layer corresponding to the first region is greater than a thickness of the first aluminum oxide film layer.

39. The back contact cell according to claim 1, characterized in that A fourth region is provided between the first region and / or the second region closest to the edge of the silicon substrate and the edge of the silicon substrate. A third insulating dielectric layer is provided on the fourth region. The thickness of the third insulating dielectric layer is greater than that of the first insulating dielectric layer.

40. The back contact cell according to claim 39, characterized in that The first insulating dielectric layer includes a first aluminum oxide film layer, and the third insulating dielectric layer includes a third aluminum oxide film layer. The ratio of oxygen to aluminum in the third aluminum oxide film layer is greater than the ratio of oxygen to aluminum in the first aluminum oxide film layer.

41. The back contact cell according to claim 1, characterized in that The first passivation layer is a tunneling oxide layer, and the first doped layer is a doped polysilicon layer; The second passivation layer is at least one of an intrinsic amorphous silicon layer or a tunneling oxide layer, and the second doped layer is at least one of a doped amorphous silicon layer and a doped microcrystalline silicon layer.

42. A battery assembly, characterized in that: A back contact battery comprising any one of several claims 1-41.

43. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 42.

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