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, and a first doped layer of the back contact cell comprises an insulating region and a conductive region. The insulating layer is disposed in the insulating region of the first doped layer. And at least part of the second doping layer comprises a first stacking part covering the second region and a second stacking part extending to the insulating region of the first doping layer. And the second stacking part covers at least partial area of the conductive area in a stacking manner. The first electrode penetrates through the insulating layer and is conductively connected with the first doping layer. The conductive thin film layer is stacked on the second doping layer, the conductive thin film layer extends to at least partial area of the part, corresponding to the conductive area, of the second stacking part, the conductive thin film layer is insulated and isolated from the first electrode, and the second electrode is arranged on the conductive thin film layer. Therefore, through the matching optimization design of the first doping layer, the second doping layer, the conductive thin film layer and the insulating layer, the hot spot resistance and efficiency of the back contact cell can achieve a better matching effect.

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] To improve the efficiency of back-contact cells, one of the doped layers can be set as a polycrystalline silicon layer, and the other doped layer can be set as an amorphous silicon layer or a microcrystalline silicon layer, thereby forming a hybrid back-contact cell. However, although this can improve the efficiency of the cell, when the back-contact cell is used, if obstructions in the external environment block the cell, the obstructed cell will experience a hot spot phenomenon, causing the temperature to rise. When the temperature exceeds a certain value, it is easy to cause damage to the component or even cause a fire.

[0004] In related technologies, to improve the hot spot resistance of back-contact cells, two doped layers of different polarities are stacked together in a localized area to form a leakage region, intentionally introducing leakage points. However, this technical solution does not consider the matching between hot spot resistance and cell efficiency. While improving hot spot resistance, it can easily lead to a significant reduction in efficiency. Therefore, how to balance the relationship between hot spot resistance and conversion efficiency of hybrid back-contact cells so that hot spot resistance and conversion efficiency can achieve a better match has become a technical problem that technicians are studying. 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 opposite to each other, the backlight surface comprising a plurality of first regions and a plurality of second regions alternately arranged along a first direction, the first regions and the second regions both extending along a second direction intersecting the first direction;

[0008] A first passivation layer and a first doping layer are sequentially stacked on the first region, wherein a surface of the first doping layer facing away from the silicon substrate comprises a conductive region and an insulating region;

[0009] an insulating layer stacked on the insulating region;

[0010] a second passivation layer and a second doped layer stacked sequentially on the second region, wherein at least a portion of the second doped layer includes a first stacking portion covering only the second region and a second stacking portion extending at least onto the conductive region, wherein the second stacking portion is stacked and covers at least a portion of the conductive region;

[0011] a first electrode, the first electrode being disposed in a region corresponding to the insulating layer and penetrating the insulating layer and being conductively connected to the first doping layer;

[0012] The conductive thin film layer is stacked on the second doped layer, the conductive thin film layer on the second doped layer having the second stacking portion extends to at least a portion of the second stacking portion corresponding to the conductive area, and the conductive thin film layer is insulated and isolated from the first electrode; and

[0013] A second electrode is disposed on the conductive film layer and is electrically connected to the conductive film layer.

[0014] In some embodiments, the first passivation layer is a tunneling oxide layer, and the first doped layer is a doped polysilicon layer;

[0015] 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.

[0016] In some embodiments, the second stack portion includes a leakage contact segment and an insulating contact segment, the leakage contact segment is stacked and covered on the conductive area, the insulating contact segment is stacked and covered on the insulating layer, the conductive film layer extends to at least a portion of the leakage contact segment, and the first electrode passes through the insulating contact segment and the insulating layer and is conductively connected to the first doped layer.

[0017] In some embodiments, the conductive film layer only extends onto the leakage contact segment and covers a portion of the leakage contact segment.

[0018] In some embodiments, a length of a portion of the conductive film layer extending onto the leakage contact segment in the first direction is greater than or equal to 10 μm.

[0019] In some embodiments, a ratio of a length of a portion of the conductive film layer extending onto the leakage contact segment in the first direction to a length of the leakage contact segment in the first direction is greater than 90%.

[0020] In some embodiments, the conductive film layer extends to cover the entire leakage contact segment and partially covers the insulating contact segment.

[0021] In some embodiments, in the first direction, the length of the leakage contact segment is 10 μm-600 μm, and in the second direction, the length of the leakage contact segment is 10 μm-5000 μm.

[0022] In some embodiments, in the first direction, the length of the leakage contact segment is 10 μm-150 μm, and in the second direction, the length of the leakage contact segment is 20 μm-500 μm.

[0023] In some embodiments, in a single second stack portion, the area of ​​the portion of the conductive film layer corresponding to the leakage contact segment is 100 μm 2 -50000μm 2 .

[0024] In some embodiments, in the back contact cell, the ratio of the sum of the areas of the portions of all the conductive film layers corresponding to the leakage contact segments to the area of ​​the backlight surface is 1.5*10 -8 -1.5*10 -5 .

[0025] In some embodiments, in the second doping layer, the first stack portion extends continuously along the second direction, and the second stack portion is formed at a preset position of the first stack portion.

[0026] In some embodiments, in the second direction, one side of the first stacking portion has a plurality of second stacking portions arranged at intervals.

[0027] In some embodiments, in the second direction, a distance between two adjacent second stacking portions located on one side of the first stacking portion is 1 cm-10 cm.

[0028] In some embodiments, in the second direction, a distance between two adjacent second stacking portions located on one side of the first stacking portion is greater than or equal to 2 cm and less than 4 cm.

[0029] In some embodiments, in the first direction, a distance between the first electrode and the conductive film layer is greater than or equal to 10 μm.

[0030] In some embodiments, the insulating layer is a phosphosilicate glass layer, a borosilicate glass layer, or a borophosphosilicate glass layer; or

[0031] The insulating layer includes at least one of a silicon nitride film layer and an aluminum oxide film layer; or

[0032] The insulating layer is a double-layer film structure, in which the film layer structure close to the silicon substrate in the insulating layer includes at least one of an aluminum oxide film layer and a silicon oxide film layer, and the film layer structure facing away from the silicon substrate includes at least one of a silicon nitride film layer, a silicon oxynitride film layer and a silicon oxide film layer.

[0033] In some embodiments, the silicon substrate further includes a plurality of side surfaces connecting the light-receiving surface and the backlight surface, a third passivation layer is stacked on at least a portion of the side surfaces, and a fourth passivation layer is provided on the light-receiving surface.

[0034] In some embodiments, the plurality of side surfaces include a cutting surface, the third passivation layer is stacked on the side surfaces other than the cutting surface, and the fifth passivation layer is stacked on the cutting surface.

[0035] The present application also provides a battery assembly, which includes several back-contact batteries as described in any one of the above items.

[0036] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0037] In the back-contact cell, cell assembly, and photovoltaic system of the embodiments of the present application, the surface of the first doped layer facing away from the silicon substrate includes an insulating region and a conductive region, and the insulating layer is stacked on the insulating region of the first doped layer. At least part of the second doped layer includes a first stacking portion that only covers the second region and a second stacking portion that extends to the insulating region of the first doped layer, that is, the second stacking portion extends from the first stacking portion to the conductive region of the first doped layer. The second stacking portion is stacked and covers at least part of the conductive region. The first electrode is provided in the region corresponding to the insulating layer and is conductively connected to the first doped layer through the insulating layer. The conductive thin film layer is stacked on the second doped layer, and the conductive thin film layer on the second doped layer having the second stacking portion extends to at least part of the region of the portion corresponding to the conductive region of the second stacking portion. The conductive thin film layer is insulated and isolated from the first electrode, and the second electrode is provided on the conductive thin film layer and is conductively connected to the conductive thin film layer. Thus, by designing the second stacked portion and the conductive film layer extending above the second doped layer, the second stacked portion can form a leakage path at a location corresponding to the conductive region of the first doped layer, thereby forming a leakage point in the thickness direction. This can reduce the reverse breakdown voltage of the back-contact cell when it is blocked, thereby improving the back-contact cell's resistance to hot spot effects and reducing the risk of hot spot effects in the battery module. Furthermore, by optimizing the matching design of the first doped layer, the second doped layer, the conductive film layer, and the insulating layer, the back-contact cell's resistance to hot spot effects and efficiency can be optimally matched, improving the resistance to hot spot effects while maintaining the efficiency of the back-contact cell.

[0038] 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

[0039] Figure 1 This is a module schematic diagram of a photovoltaic system provided by an embodiment of the present application;

[0040] Figure 2 Schematic diagram of a module of a battery assembly provided in an embodiment of the present application;

[0041] Figure 3 Schematic diagram of the planar structure of a back-contact battery provided in an embodiment of the present application;

[0042] Figure 4 is a cross-sectional schematic diagram of a back-contact battery provided in an embodiment of the present application;

[0043] Figure 5 is another cross-sectional schematic diagram of a back-contact battery provided in an embodiment of the present application;

[0044] Figure 6 is another cross-sectional schematic diagram of a back-contact battery provided in an embodiment of the present application;

[0045] Figure 7 is another cross-sectional schematic diagram of a back-contact battery provided in an embodiment of the present application;

[0046] Figure 8 This is another cross-sectional schematic diagram of the back-contact battery provided in an embodiment of the present application.

[0047] Description of main component symbols:

[0048] 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, first passivation layer 20, first doped layer 30, conductive region 301, insulating region 302, insulating layer 40, second passivation layer 50, second doped layer 60, first stacking portion 61, second stacking portion 62, leakage contact segment 621, insulating contact segment 622, conductive film layer 70, first electrode 80, second electrode 90, third passivation layer 110, fourth passivation layer 120. DETAILED DESCRIPTION

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] See also Figure 3 and Figure 4 The back contact battery 100 in the embodiment of the present application may include a silicon substrate 10, a first passivation layer 20, a first doping layer 30, an insulating layer 40, a second passivation layer 50, a second doping layer 60, a conductive film layer 70, a first electrode 80 and a second electrode 90.

[0058] The silicon substrate 10 has a light-receiving surface 11 and a backlight surface 12 opposite to each other. The backlight surface 12 includes a plurality of first regions 121 and a plurality of second regions 122. The plurality of first regions 121 and the plurality of second regions 122 are alternately arranged along a first direction, and both the first regions 121 and the second regions 122 extend along a second direction that intersects the first direction.

[0059] Specifically, if Figure 3As shown, the first regions 121 and the second regions 122 can be alternately arranged along the lateral direction of the silicon substrate 10 and both extend along the longitudinal direction. That is, the first direction can be the lateral direction of the back-contact cell 100, and the second direction can be the lateral direction of the back-contact cell 100, with the two being perpendicular to each other. Of course, in other embodiments, the first direction and the second direction can also be other directions, for example, both can be diagonal directions of the silicon substrate 10, and this is not limited here.

[0060] The first passivation layer 20 and the first doping layer 30 are sequentially stacked on the first region 121, that is, along the thickness direction of the back contact battery, the first passivation layer 20 and the first doping layer 30 are sequentially stacked on the first region 121, and the first passivation layer 20 and the first doping layer 30 completely cover the first region 121. Each first region 121 is provided with the first passivation layer 20 and the first doping layer 30. Figure 4 As shown, the surface of the first doped layer 30 facing away from the silicon substrate 10 has a conductive region 301 and an insulating region 302 .

[0061] The insulating layer 40 is stacked on the insulating region 302 of the first doping layer 30, and the second passivation layer 50 and the second doping layer 60 are stacked in sequence on the second region 122. That is, along the thickness direction of the back contact battery, the second passivation layer 50 and the second doping layer 60 are stacked in sequence on the second region 122. The second passivation layer 50 and the second doping layer 60 both completely cover the second region 122, and each second region 122 is provided with a second passivation layer 50 and a second doping layer 60.

[0062] like Figure 4 As shown, at least a portion of the second doped layer 60 includes a first stacking portion 61 that only covers the second region 122 and a second stacking portion 62 that extends onto the conductive region 301 of the first doped layer 30. That is, the second stacking portion 62 extends from the first stacking portion 61 to the conductive region 301 of the first doped layer 30. The second stacking portion 62 is stacked and covers at least a portion of the conductive region 301. Specifically, the second stacking portion 62 forms a leakage contact with the first doped layer 30 in the conductive region 301. That is, the second stacking portion 62 forms a leakage contact structure with the first doped layer 30 in the conductive region 301 along the thickness direction of the back contact cell.

[0063] The first electrode 80 is disposed in a region corresponding to the insulating layer 40 and penetrates the insulating layer 40 to be conductively connected to the first doped layer 30. A conductive thin film layer 70 is stacked on the second doped layer 60. The conductive thin film layer 70 on the second doped layer 60 having the second stacking portion 62 extends to at least a portion of the portion of the second stacking portion 62 corresponding to the conductive region 301. The conductive thin film layer 70 is insulated and isolated from the first electrode 80. The second electrode 90 is disposed on the conductive thin film layer 70 and is conductively connected to the conductive thin film layer 70.

[0064] It should be noted that, in this article, a certain film layer covers or is stacked to cover a partial area or the entire area of ​​a certain surface or a certain film layer. The film layer may be directly stacked on the surface or a certain film layer, or other film layers may be arranged between the film layer and the surface or film layer. Covering is only used to limit the specific setting range of the film layer.

[0065] In addition, it should be noted that, in this article, "leakage contact" means that there is no insulation between the second stack portion 62 and the conductive area 301 of the first doped layer 30, but leakage conduction forms a leakage point. The two can be directly in contact to form a leakage point, or tunneling can be achieved through other dielectric layers to achieve the function of leakage contact.

[0066] For example, Figure 4 As shown, in some embodiments, a second passivation layer 50 may also be provided between the second stack portion 62 and the conductive region 301. The second stack portion 62 is electrically connected to the first doped layer 30 at the conductive region 301 through the passivation layer. In this case, the first passivation layer 20 and the first doped layer 30 constitute a first passivation contact structure, and the second passivation layer 50 and the second passivation layer 50 constitute a second passivation contact structure. The first passivation contact structure is stacked in the first region 121, and the second passivation contact structure is stacked in the second region 122 and extends to cover the insulating region 302 of the first doped layer 30 and at least partially covers the conductive region 301.

[0067] In the back-contact cell 100, cell assembly 200, and photovoltaic system 1000 of the embodiments of the present application, the surface of the first doped layer 30 facing away from the silicon substrate 10 includes an insulating region 302 and a conductive region 301, and the insulating layer 40 is stacked on the insulating region 302 of the first doped layer 30. At least a portion of the second doped layer 60 includes a first stacking portion 61 that only covers the second region 122 and a second stacking portion 62 that extends onto the insulating region 302 of the first doped layer 30. That is, the second stacking portion 62 extends from the first stacking portion 61 to the conductive region 301 of the first doped layer 30. The second stacking portion 62 is stacked and covers at least a portion of the conductive region 301. The first electrode 80 is disposed in a corresponding region of the insulating layer 40 and penetrates the insulating layer 40 to be conductively connected to the first doped layer 30. The conductive film layer 70 is stacked on the second doped layer 60. The conductive film layer 70 on the second doped layer 60 having the second stacking portion 62 extends to at least a portion of the portion of the second stacking portion 62 corresponding to the conductive region 301. The conductive film layer 70 is insulated and isolated from the first electrode 80. The second electrode 90 is disposed on the conductive film layer 70 and is conductively connected to the conductive film layer 70. In this way, through the design of the second stacking portion 62 and the extended conductive film layer 70 on the second doped layer 60, the second stacking portion 62 can form a leakage channel at a position corresponding to the conductive region 301 of the first doped layer 30, thereby forming a leakage point in the thickness direction, which can reduce the reverse breakdown voltage of the back-contact battery 100 when it is blocked, thereby improving the anti-hot spot performance of the back-contact battery 100 and reducing the hot spot risk of the battery assembly 200.

[0068] At the same time, through the design of the insulating layer 40, it is possible to avoid the second stacking portion 62 from extending too long in the first direction, which would result in an excessively large leakage area and thus a loss of efficiency. At the same time, the provision of the insulating layer 40 can further improve the passivation effect of the back-contact battery, balance the relationship between the anti-hot spot performance and the efficiency, and enable the anti-hot spot performance and the efficiency to achieve a better matching effect.

[0069] That is to say, in the present application, by optimizing the matching design of the first doped layer 30, the second doped layer 60, the conductive film layer 70 and the insulating layer 40, the anti-hot spot performance and efficiency of the back contact battery can be better matched, thereby improving the anti-hot spot performance while ensuring the efficiency of the back contact battery.

[0070] Specifically, in the embodiments of the present application, the silicon substrate 10 can be an N-type silicon substrate 10 or a P-type silicon substrate 10, without limitation. The first doped layer 30 can be an N-type doped layer, and the second doped layer 60 can be a P-type doped layer, or the first doped layer 30 can be a P-type doped layer, and the second doped layer 60 can be a P-type doped layer, without limitation, as long as the polarities of the two layers are opposite.

[0071] The conductive film layer 70 may preferably be a transparent conductive film layer, such as a TCO film layer, which can improve the bifaciality of the back contact battery while achieving current collection. In other embodiments, the conductive film layer 70 may also be a metal film layer, such as at least one of an aluminum layer, a nickel layer, a copper layer, and the like. Of course, in some embodiments, the conductive film layer 70 may also be a double-layer structure consisting of a transparent conductive film layer and a metal film layer, which is not specifically limited here. In the embodiment of the present application, a conductive film layer 70 is correspondingly provided on each second doped layer 60, and the conductive film layers 70 are arranged at intervals. During the manufacturing process, a conductive film covering the entire back side 12 may be prepared first, and then an insulating groove is opened on the portion of the conductive film corresponding to the insulating area 302, and the insulating groove passes through both ends of the conductive film along the second direction, thereby forming a plurality of spaced conductive film layers 70.

[0072] In the present application, the first electrode 80 directly penetrates the insulating layer 40 and is conductively connected to the first doping layer 30 , and the second electrode 90 can be set on the conductive film layer 70 , and the second electrode 90 forms a conductive connection with the second doping layer 60 through the conductive film layer 60 .

[0073] In an embodiment of the present application, the back contact cell may be a hybrid back contact cell. Specifically, in such a back contact cell, the first doped layer 30 may be a doped polysilicon layer and the polarity of the first doped layer 30 is N-type, that is, the first doped layer 30 may be an N-type 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 first doped layer 30 may be at least one of a doped amorphous silicon layer and a doped microcrystalline silicon layer. In this way, by designing the first doped layer 30 as a doped polysilicon layer and the second doped layer 60 as at least one of a doped amorphous silicon layer and a doped microcrystalline silicon layer, a hybrid back contact cell can be formed, thereby improving the efficiency of the back contact cell.

[0074] In a preferred embodiment, the first passivation layer 20 is a tunneling oxide layer, the first doping layer 30 is an N-type doped polysilicon layer, the second passivation layer 50 is an intrinsic amorphous silicon layer, and the second doping layer 60 is a P-type doped amorphous silicon layer or a P-type doped microcrystalline silicon layer.

[0075] It can be understood that due to the poor lateral conductivity of doped amorphous silicon and doped microcrystalline silicon, a stacking structure in the thickness direction is formed at the conductive area 301 of the first doped layer 30 through the second stacking part 62, so that the first doped layer 30 and the second doped layer 60 can form a leakage contact structure in the thickness direction, thereby improving the efficiency of the back contact battery.

[0076] Furthermore, in an embodiment of the present application, the lateral conductivity of doped amorphous silicon and doped microcrystalline silicon is relatively poor, and the first region 121 and the second region 122 may not be isolated by a groove, that is, the first doped layer 30 and the first stacking portion 61 may not need to be isolated by a groove, and the first stacking portion 61 of the second doped layer 60 and the first doped layer 30 may be adjacent in the first direction, and the two do not need to be isolated by designing a groove or other insulating structure, which can increase the coverage area of ​​the doped layer on the backlight surface 12 and further improve the efficiency of the back contact battery.

[0077] In an embodiment of the present application, the first passivation layer 20 may be a tunneling oxide layer, the first doping layer 30 may be a doped polycrystalline silicon layer, the second passivation layer 50 may be at least one of an intrinsic amorphous silicon layer or a tunneling oxide layer, the second doping layer 60 may be at least one of a doped amorphous silicon layer and a doped microcrystalline silicon layer, and the conductive film layer 70 on the second doping layer 60 having a second stacking portion 62 extends to at least a partial area of ​​the portion of the second stacking portion 62 corresponding to the conductive area 301.

[0078] In this case, on the second stacking portion 62 located in the conductive area 301, the area covered by the conductive film layer 70 is the effective leakage area, and the area not covered by the conductive film layer 70 is the invalid leakage area. In the back-contact battery, only the effective leakage area can play a role in improving the anti-hot spot performance.

[0079] In addition, if Figure 3 As shown, in the embodiment of the present application, in the back-contact battery, all the second doping layers 60 may have the second stacking portion 62, or only part of the second doping layers 60 may have the second stacking portion 62. There is no specific limitation here, as long as the leakage contact area formed by the second stacking portion 62 and the first doping layer 30 does not cause a significant reduction in the efficiency of the back-contact battery.

[0080] like Figure 3 As shown, for a single second doping layer 60 , one or more second stacking parts 62 may be formed on the first stacking part 61 . When there are multiple second stacking parts 62 , the second stacking parts 62 may be spaced apart along the second direction on the first stacking part 61 .

[0081] In some embodiments, the insulating layer 40 may be a film layer with an insulating function, which may be obtained by partially etching and removing a mask layer stacked and covering the first doping layer 30 during the production process.

[0082] In some embodiments, the insulating layer 40 may be a phosphosilicate glass film layer, a borosilicate glass film layer, or a borophosphosilicate glass film layer, which may be film layers automatically formed on the first doping layer 30 during the manufacturing process.

[0083] Of course, in some embodiments, the insulating layer 40 may also be at least one of an aluminum oxide film layer and a silicon nitride film layer.

[0084] Furthermore, in some embodiments, the insulating layer 40 may also be at least one of a silicon oxide film layer and a silicon oxynitride film layer, which is not specifically limited herein.

[0085] Furthermore, in some embodiments, the insulating layer 40 may be a double-layer film structure, wherein the film layer structure close to the silicon substrate 10 in the insulating layer 40 may include at least one of an aluminum oxide film layer or a silicon oxide film layer, and the film layer structure facing away from the silicon substrate 10 may include at least one of a silicon nitride film layer, a silicon oxynitride film layer or a silicon oxide film layer, and no specific limitation is given here.

[0086] See also Figure 4 In some embodiments, the second stack portion 62 may include a leakage contact segment 621 and an insulating contact segment 622, wherein the leakage contact segment 621 is stacked and covered on the conductive region 301, and the insulating contact segment 622 is stacked and covered on the insulating layer 40. The conductive film layer 70 extends to at least a portion of the leakage contact segment 621, and the first electrode 80 penetrates the insulating contact layer and the insulating segment 622 and is conductively connected to the first doped layer 30.

[0087] In this way, the leakage contact segment 621 can completely cover the conductive area 301 and form a leakage contact with the first doped layer 30, and the insulating contact segment 622 is covered on the insulating layer 40 and isolated from the first doped layer 30 by the insulating layer 40. Through the setting of the insulating layer 40, it can be avoided that the length of the second stacking part 62 extending in the first direction is too long during the manufacturing process, resulting in an excessively large leakage contact area and excessive efficiency loss. That is, through the setting of the insulating layer 40, the efficiency of the back contact battery can be guaranteed while improving the anti-hot spot performance.

[0088] 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 is at least one of a tunneling oxide layer and an intrinsic amorphous silicon layer, and the second doped layer 60 is at least one of a doped amorphous silicon layer and a doped microcrystalline silicon layer. The insulating contact segment 622 may completely cover the insulating layer 40 or may only cover a portion of the insulating layer 40, without limitation herein.

[0089] It should be noted that when the first doped layer 30 is a doped polycrystalline silicon layer and the second doped layer 60 is a doped amorphous silicon layer or a doped microcrystalline silicon layer, the area covered by the conductive film layer 70 on the leakage contact segment 621 is the effective leakage area, while the area not covered by the conductive film layer 70 is the ineffective leakage area. In such an embodiment, the projected area of ​​the portion of the conductive film layer 70 located on the leakage contact segment 621 in the thickness direction of the back contact cell is the effective leakage area.

[0090] See also Figure 4 In some embodiments, the conductive film layer 70 extends to cover the entire leakage contact segment 621 and partially covers the insulating contact segment 622 .

[0091] In this way, the conductive film layer 70 can completely cover the entire leakage contact segment 621 , and the area of ​​the entire leakage contact segment 621 is the effective leakage contact area between the second stacking portion 62 and the first doped layer 30 .

[0092] See also Figure 3 In some embodiments, the length L1 of the leakage contact segment 621 in the first direction may be 10 μm-600 μm, and the length L2 of the leakage contact segment 621 in the second direction may be 10 μm-5000 μm.

[0093] In this way, by reasonably setting the length of the leakage contact segment 621 in various directions, the area of ​​the leakage contact segment 621 can be controlled within a reasonable range, thereby controlling the effective leakage contact area of ​​the single second stacking part 62 within a reasonable range, avoiding the leakage contact area being too small, resulting in the anti-hot spot performance failing to achieve the expected effect, and avoiding the leakage contact area being too large, resulting in excessive efficiency loss. That is, such a setting can balance the relationship between anti-hot spot performance and efficiency, so as to achieve a better matching effect.

[0094] Specifically, in such an embodiment, the length of the leakage contact segment 621 in the first direction may be, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, or any value between 10 μm and 600 μm. The length of the leakage contact segment 621 in the second direction may be, for example, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, 1000 μm, 1500 μm, 2000 μm, 2500 μm, 3000 μm, 3500 μm, 4000 μm, 4500 μm, 5000 μm, or any value between 10 μm and 5000 μm.

[0095] Furthermore, in such an embodiment, the length L1 of the leakage contact segment 621 in the first direction is preferably 10 μm-150 μm, and the length L2 of the leakage contact segment 621 in the second direction is preferably 20 μm-500 μm.

[0096] like Figure 4 and Figure 5 As shown, in some embodiments, in a single second doping layer 60, at least one second stacking portion 62 may be provided on both sides of the first stacking portion 61 in the first direction. Figure 4 As shown, in some embodiments, the second stacking portions 62 on both sides each cover a conductive region 301 so that both second stacking portions 62 are in leakage contact with the first doped layer 30 (i.e., the number of conductive regions 301 corresponds to the number of second stacking portions 62), thereby forming at least one leakage contact point on both sides of the second doped layer 60. Generally speaking, in such embodiments, both sides of the second doped layer 60 have a leakage contact point.

[0097] Of course, if Figure 5 As shown, in some embodiments, although at least one second stacking portion 62 is provided on both sides, an insulating layer 40 is provided below the second stacking portion 62 on one side, that is, a conductive region 301 is provided only on one side of the insulating region 302. In this case, the second stacking portion 62 on one side covers one conductive region 301 so that the second stacking portion 62 is in leakage contact with the first doped layer 30, while the second stacking portion 62 on the other side is insulated and isolated from the first doped layer 30 by the insulating layer 40 (that is, one second stacking portion 62 corresponds to the conductive region 301, and the other second stacking portion 62 corresponds to the insulating region 302), thereby providing leakage points only on one side of the second doped layer 60. Generally speaking, in such embodiments, leakage contact points are provided only on one side of the second doped layer 60.

[0098] See also Figure 6 In some embodiments, the conductive film layer 70 may also only extend onto the leakage contact segment 621 and cover a portion of the leakage contact segment 621 .

[0099] In this way, the conductive film layer 70 can cover only a portion of the leakage contact segment 621 , thereby controlling the effective leakage contact area of ​​the first doping layer 30 and the second doping layer 60 .

[0100] exist Figure 6 In the illustrated embodiment, the length of the portion of the conductive film layer 70 extending onto the leakage contact segment 621 in the first direction is greater than or equal to 10 μm.

[0101] In this way, it is possible to avoid the extension length of the conductive film layer 70 being too short, which would result in poor anti-hot spot performance.

[0102] Furthermore, in such an embodiment, the ratio of the length of the portion of the conductive film layer 70 extending onto the leakage contact segment 621 in the first direction to the length of the leakage contact segment 621 in the first direction is greater than 90%, for example, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc.

[0103] Thus, by setting the ratio of the length of the conductive film layer 70 extending onto the leakage contact segment 621 to the length of the leakage contact segment 621 to be greater than 90%, the hot spot resistance can be effectively improved while ensuring the conversion efficiency.

[0104] Specifically, as described above, in some embodiments, the length of the leakage contact segment 621 in the first direction is 10 μm-600 μm, preferably 10 μm-150 μm. Then, in this embodiment, the minimum length of the portion of the conductive film layer 70 extending to the leakage contact segment 621 in the first direction is greater than 9 μm, and the maximum length may be greater than 540 μm and less than or equal to 600 μm, preferably greater than 135 μm and less than 150 μm.

[0105] Similarly, if Figure 6 and Figure 7 As shown, in some embodiments, in a single second doping layer 60, at least one second stacking portion 62 may be provided on both sides of the first stacking portion 61 in the first direction. Figure 6 As shown, in some embodiments, the second stacking portions 62 on both sides respectively cover a conductive region 301, so that both second stacking portions 62 are in leakage contact with the first doped layer 30, thereby forming at least one leakage contact point on both sides of the second doped layer 60. Generally speaking, in such embodiments, both sides of the second doped layer 60 have a leakage contact point.

[0106] Of course, if Figure 7 As shown, in some embodiments, although at least one second stacking portion 62 is present on both sides, an insulating layer 40 is present beneath the second stacking portion 62 on one side. That is, a conductive region 301 is present only on one side of the insulating region 302. In this case, the second stacking portion 62 on one side covers one conductive region 301, thereby establishing leakage contact between the second stacking portion 62 and the first doped layer 30, while the second stacking portion 62 on the other side is insulated and isolated from the first doped layer 30 by the insulating layer 40. In other words, in such embodiments, leakage contact points are present only on one side of the second doped layer 60. In general, in such embodiments, leakage contact points are present only on one side of the second doped layer 60.

[0107] See also Figure 3In some embodiments, in the second doping layer 60 , the first stacking portion 61 extends continuously along the second direction, and the second stacking portion 62 is formed at a predetermined position of the first stacking portion 61 .

[0108] In this way, the second doping layer 60 has the second stacking portion 62 only at a local preset position of the first stacking portion 61 , which can avoid the area of ​​the second stacking portion 62 being too large, resulting in an excessively large area of ​​the effective leakage region and a significant decrease in efficiency.

[0109] Of course, it is understood that, in one possible embodiment, in the second doped layer 60, the second stacking portion 62 may also extend continuously along the second direction to both sides of the first stacking portion 61 in the second direction. In such a case, in order to control the area of ​​the effective leakage region, it is possible to avoid excessive efficiency loss by controlling the area covered by the conductive film layer 70 on the leakage contact segment 621.

[0110] See also Figure 6 In some embodiments, a single second doping layer 60 may include multiple second stacking portions 62 , with the multiple second stacking portions 62 being spaced apart in the second direction. That is, in the second direction, one side of the first stacking portion 61 may have multiple spaced apart second stacking portions 62 .

[0111] In this way, by providing a plurality of isolated second stacking portions 62 on the second doping layer 60 , it is possible to avoid excessive leakage contact area on a single second doping layer 60 , which would result in excessive efficiency loss.

[0112] It can be understood that, in some embodiments, when the second doping layer 60 forms leakage contact with two adjacent first doping layers 30, a second stacking portion 62 is formed on both sides of the second doping layer 60 in the first direction; when the second doping layer 60 forms leakage contact with only one first doping layer 30, a second stacking portion 62 is formed only on one side of the second doping layer 60 in the first direction.

[0113] Furthermore, in some embodiments, in the second direction, a distance H1 between two adjacent second stacking portions 62 is 1 cm-10 cm.

[0114] In this way, it is possible to avoid the interval H1 between two adjacent second stacking portions 62 being too small and the leakage points being too concentrated, which would result in the heat being unable to be dissipated in time and causing a significant temperature increase.

[0115] Specifically, in such an embodiment, the distance H1 between two adjacent second stacking portions 62 may be, for example, 1 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm, 5 cm, 5.5 cm, 6 cm, 6.5 cm, 7 cm, 7.5 cm, 8 cm, 8.5 cm, 9 cm, 9.5 cm, 10 cm or any value between 1 cm and 10 cm.

[0116] Furthermore, in such an embodiment, in the second direction, the distance H1 between two adjacent second stacking portions 62 is preferably greater than or equal to 2 cm and less than 4 cm.

[0117] In this way, through the research and demonstration of the inventors of this application, setting the spacing within this preferred range can avoid excessive heat concentration to the greatest extent while setting a larger number of second stacking parts 62. In other words, this can balance the relationship between anti-hot spot performance and excessive heat concentration, so as to achieve the optimal matching effect.

[0118] Specifically, in such an embodiment, the distance H1 between two adjacent second stacking portions 62 may preferably be, for example, 2 cm, 2.2 cm, 2.4 cm, 2.6 cm, 2.8 cm, 3 cm, 3.1 cm, 3.2 cm, 3.3 cm, 3.4 cm, 3.5 cm, 3.6 cm, 3.7 cm, 3.9 cm, or 3.95 cm.

[0119] In some embodiments, in the back contact cell 100, the distribution density of the second stacking parts 62 is 0.01 pieces / cm 2 -1.5 pieces / cm 2 In this way, by reasonably controlling the distribution density of the second stacking portion 62 , it is possible to avoid leakage points being distributed too concentratedly.

[0120] In such an embodiment, the distribution density of the second stacking parts 62 refers to the ratio between the sum of the number of the second stacking parts 62 on the back contact cell 100 and the area of ​​the backlight surface 12 of the back contact cell 100. Specifically, the distribution density of the second stacking parts 62 can be, for example, 0.01 pieces / cm 2 , 0.05 pieces / cm 2 , 0.1 / cm 2 , 0.2 pieces / cm 2 , 0.3 pieces / cm 2 , 0.4 / cm 2 , 0.5 pieces / cm 2 , 0.6 pieces / cm 2 , 0.7 pieces / cm 2 , 0.8 pieces / cm 2 , 0.9 pieces / cm 2, 1 piece / cm 2 , 1.1 / cm 2 , 1.2 pieces / cm 2 , 1.3 pieces / cm 2 , 1.4 / cm 2 , 1.5 pieces / cm 2 or 0.01 / cm 2 -1.5 pieces / cm 2 Any value between .

[0121] In some embodiments, in a single second stacking portion 62 , the area of ​​the portion of the conductive film layer 70 corresponding to the leakage contact segment 621 is 100 μm. 2 -50000μm 2 .

[0122] In this way, by controlling the area of ​​the portion of the conductive film layer 70 corresponding to the leakage contact segment 621 within this reasonable range, it is possible to improve the anti-hot spot performance while ensuring that the efficiency loss is not too large.

[0123] Specifically, in such an embodiment, the area of ​​the portion of the single conductive film layer 70 corresponding to the leakage contact segment 621 may be, for example, 100 μm. 2 , 200μm 2 , 300μm 2 , 350μm 2 , 400μm 2 , 450μm 2 , 480μm 2 , 500μm 2 , 600μm 2 , 700μm 2 , 800μm 2 , 900μm 2 , 1000μm 2 , 1100μm 2 , 1200μm 2 , 1300μm 2 , 1400μm 2 , 1500μm 2 , 2000μm 2 , 3000μm 2 , 4000μm 2 , 5000μm 2 , 6000μm 2 , 7000μm 2 , 8000μm 2 , 9000μm 2 , 10000μm 2 , 15000μm2 , 20000μm 2 , 25000μm 2 , 30000μm 2 , 35000μm 2 , 40000μm 2 , 45000μm 2 , 50000μm 2 or 100 μm 2 -50000μm 2 Any value between .

[0124] In some embodiments, in a back-contact cell, the ratio of the sum of the areas of the portions of the conductive film layers 70 corresponding to the leakage contact segments 621 (i.e., the sum of the effective leakage areas of the second stacking portions 62 in the back-contact cell) to the area of ​​the backlight surface 12 is 1.5*10 -8 -1.5*10 -5 .

[0125] In this way, the ratio of the sum of the areas of the parts of all conductive film layers 70 corresponding to the leakage contact segments 621 to the area of ​​the backlight surface 12 is set within this reasonable range, which can avoid the leakage contact area accounting for too large a proportion and seriously affecting the efficiency of the back contact battery 100, that is, the efficiency of the back contact battery 100 can be guaranteed while ensuring the anti-hot spot performance.

[0126] Specifically, in such an embodiment, the ratio of the areas of the two may be, for example, 1.5*10 -8 , 2*10 -8 , 2.5*10 -8 、3.5*10 -8 、4.5*10 -8 、4.5*10 -8 , 5*10 -8 , 6*10 -8 , 7*10 -8 、8*10 -8 、9*10 -8 , 1*10 -7 , 1*10 -6 , 1*10 -5 , 1.5*10 -5 Or 4.5*10 -8 -1.5*10 -5 In some embodiments, the ratio between the two values ​​may be preferably greater than 1.5*10 -8 And less than 4.5*10 -8 .

[0127] In some embodiments, in the first direction, the distance between the first electrode 80 and the conductive film layer 70 is greater than or equal to 10 μm. In this way, efficient insulation isolation between the conductive film layer 70 and the second portion 72 can be achieved.

[0128] See also Figure 8 In some embodiments, the silicon substrate 10 further includes several side surfaces connecting the light-receiving surface 11 and the backlight surface 12 , a third passivation layer 110 is stacked on at least some of the side surfaces, and a fourth passivation layer 120 is provided on the light-receiving surface 11 .

[0129] In this way, the light-receiving surface 11 and the side surfaces can be efficiently passivated by the third passivation layer 110 and the fourth passivation layer 120 , thereby protecting the side surfaces and improving the passivation effect of the back contact cell.

[0130] Specifically, in such an embodiment, the third passivation layer 110 may also be at least one of an aluminum oxide film layer or a silicon nitride film layer. In addition, in some embodiments, the third passivation layer 110 may also be at least one of a silicon oxide film layer or a silicon oxynitride film layer, and the specific embodiments are not limited here. Of course, in some embodiments, the third passivation layer 110 may also be a double-layer film structure, wherein the film layer structure of the third passivation layer 110 close to the silicon substrate 10 may include at least one of an aluminum oxide film layer or a silicon oxide film layer, and the film layer structure facing away from the silicon substrate 10 may include at least one of a silicon nitride film layer, a silicon oxynitride film layer, or a silicon oxide film layer, and the specific embodiments are not limited here.

[0131] The fourth passivation layer 120 may also be at least one of an aluminum oxide film layer or a silicon nitride film layer. In addition, in some embodiments, the fourth passivation layer 120 may also be at least one of a silicon oxide film layer or a silicon oxynitride film layer, which is not specifically limited here. Of course, in some embodiments, the fourth passivation layer 120 may also be a double-layer film structure, wherein the film layer structure of the fourth passivation layer 120 close to the silicon substrate 10 may include at least one of an aluminum oxide film layer or a silicon oxide film layer, and the film layer structure facing away from the silicon substrate 10 may include at least one of a silicon nitride film layer, a silicon oxynitride film layer, or a silicon oxide film layer, which is not specifically limited here.

[0132] It can be understood that, in some embodiments, the back contact cell may be a full-sheet cell that has not been sliced. In such a case, the third passivation layer 110 is stacked on all sides of the back contact cell.

[0133] In some embodiments, the back-contact cell may be a sliced ​​cell obtained through a slicing process. In this case, the side surfaces of the back-contact cell include a cut surface, and a third passivation layer 110 is laminated on the side surfaces other than the cut surface, and a fifth passivation layer is laminated on the cut surface. The fifth passivation layer may be at least one of a silicon nitride film layer, a silicon oxide film layer, and a silicon oxynitride film layer.

[0134] Throughout this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" indicate 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.

[0135] 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 opposite to each other, the backlight surface comprising a plurality of first regions and a plurality of second regions alternately arranged along a first direction, the first regions and the second regions both extending along a second direction intersecting the first direction; A first passivation layer and a first doping layer are sequentially stacked on the first region, wherein a surface of the first doping layer facing away from the silicon substrate comprises a conductive region and an insulating region; an insulating layer stacked on the insulating region; a second passivation layer and a second doped layer stacked sequentially on the second region, wherein at least a portion of the second doped layer includes a first stacking portion covering only the second region and a second stacking portion extending at least onto the conductive region, wherein the second stacking portion is stacked and covers at least a portion of the conductive region; a first electrode, the first electrode being disposed in a region corresponding to the insulating layer and penetrating the insulating layer and being conductively connected to the first doping layer; a conductive thin film layer stacked on the second doped layer, wherein the conductive thin film layer on the second doped layer having the second stacking portion extends to at least a portion of the second stacking portion corresponding to the conductive region, and the conductive thin film layer is insulated and isolated from the first electrode; and A second electrode is disposed on the conductive film layer and is electrically connected to the conductive film layer.

2. The back contact battery 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.

3. The back contact battery according to claim 1, characterized in that The second stacking portion includes a leakage contact segment and an insulating contact segment, the leakage contact segment is stacked and covered on the conductive area, the insulating contact segment is stacked and covered on the insulating layer, the conductive film layer extends to at least a portion of the leakage contact segment, and the first electrode passes through the insulating contact segment and the insulating layer and is conductively connected to the first doped layer.

4. The back contact battery according to claim 3, characterized in that The conductive film layer only extends onto the leakage contact segment and covers a portion of the leakage contact segment.

5. The back contact battery according to claim 4, characterized in that The length of the portion of the conductive film layer extending onto the leakage contact segment in the first direction is greater than or equal to 10 μm.

6. The back contact battery according to claim 4, characterized in that A ratio of a length of a portion of the conductive film layer extending onto the leakage contact segment in the first direction to a length of the leakage contact segment in the first direction is greater than 90%.

7. The back contact battery according to claim 3, characterized in that The conductive film layer extends to cover the entire leakage contact segment and partially covers the insulating contact segment.

8. The back contact battery according to any one of claims 3 to 7, characterized in that: In the first direction, the length of the leakage contact segment is 10 μm-600 μm, and in the second direction, the length of the leakage contact segment is 10 μm-5000 μm.

9. The back contact battery according to claim 8, characterized in that In the first direction, the length of the leakage contact segment is 10 μm-150 μm, and in the second direction, the length of the leakage contact segment is 20 μm-500 μm.

10. The back contact battery according to claim 3, characterized in that In a single second stacked portion, the area of ​​the portion of the conductive film layer corresponding to the leakage contact segment is 100 μm 2 -50000μm 2 .

11. The back contact battery according to claim 3, characterized in that In the back contact cell, the ratio of the sum of the areas of the portions of all the conductive film layers corresponding to the leakage contact segments to the area of ​​the backlight surface is 1.5*10 -8 -1.5*10 -5 .

12. The back contact battery according to claim 1, characterized in that In the second doping layer, the first stacking portion continuously extends along the second direction, and the second stacking portion is formed at a predetermined position of the first stacking portion.

13. The back contact battery according to claim 12, characterized in that In the second direction, one side of the first stacking portion has a plurality of second stacking portions arranged at intervals.

14. The back contact battery according to claim 13, characterized in that In the second direction, a distance between two adjacent second stacking portions located on one side of the first stacking portion is 1 cm-10 cm.

15. The back contact battery according to claim 14, characterized in that In the second direction, a distance between two adjacent second stacking portions located on one side of the first stacking portion is greater than or equal to 2 cm and less than 4 cm.

16. The back contact battery according to claim 1, characterized in that In the first direction, a distance between the first electrode and the conductive film layer is greater than or equal to 10 μm.

17. The back contact battery according to claim 1, characterized in that The insulating layer is a phosphosilicate glass layer, a borosilicate glass layer, or a borophosphosilicate glass layer; or The insulating layer includes at least one of a silicon nitride film layer and an aluminum oxide film layer; or The insulating layer is a double-layer film structure, in which the film layer structure close to the silicon substrate in the insulating layer includes at least one of an aluminum oxide film layer and a silicon oxide film layer, and the film layer structure facing away from the silicon substrate includes at least one of a silicon nitride film layer, a silicon oxynitride film layer and a silicon oxide film layer.

18. The back contact battery according to claim 1, characterized in that The silicon substrate further includes a plurality of side surfaces connecting the light-receiving surface and the backlight surface, a third passivation layer is stacked on at least a portion of the side surfaces, and a fourth passivation layer is provided on the light-receiving surface.

19. The back contact cell according to claim 18, characterized in that The plurality of side surfaces include a cutting surface, the side surfaces other than the cutting surface are stacked with the third passivation layer, and the cutting surface is stacked with a fifth passivation layer.

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

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

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