Back contact battery, battery string, battery assembly and photovoltaic system

Abstract

The utility model is suitable for the technical field of solar cells, and provides a back contact cell, a cell string, a cell assembly and a photovoltaic system.The back contact cell comprises a silicon substrate, a first doping layer, a first insulating layer, a second doping layer and a conductive contact structure, and a first groove and a protruding part which are arranged in the first direction are formed on the back face of the back contact cell; the first doped layer is stacked on the convex part, the first doped layer comprises a first sub-doped layer and a second sub-doped layer which are stacked, the second doped layer is stacked in the first groove, the polarity of the second doped layer is opposite to that of the first doped layer, and the conductive contact structure comprises an extension part; the thickness of the extending part in the thickness direction is larger than that of the convex part, the first doping layer and the first insulating layer. Therefore, the conductive contact structure can be used as a heat dissipation point, and the influence of hot spots is reduced or even eliminated. In addition, the thickness of the extending part in the thickness direction is large, the extending part can be electrically connected with the first doping sub-layer and the second doping sub-layer, a plurality of electric leakage points are formed, and the safety is further improved.

Description

Technical Field

[0001] This application belongs to the technical field of solar cells, and particularly relates to a back-contact cell, a battery string, a battery module, and a photovoltaic system. Background Art

[0002] Solar energy is a sustainable source of clean energy. Solar cells can convert solar energy into electrical energy by utilizing the photovoltaic effect of the semiconductor p-n junction. Currently, a back-contact solar cell is a cell in which both the emitter and base contact electrodes are placed on the back surface (non-light-receiving surface) of the cell. The back-contact cell will have two doped layers with opposite conduction types on the back surface of the cell, separated by trenches or insulating layers in the middle. The safety performance of a photovoltaic module equipped with an existing back-contact cell needs to be improved. Summary of the Utility Model

[0003] This application provides a back-contact cell, a battery string, a battery module, and a photovoltaic system, aiming to solve the problem that hot spots will occur during the use of photovoltaic cells.

[0004] The back-contact cell provided by this application includes a silicon substrate, a first doped layer, a first insulating layer, a second doped layer, and a conductive contact structure. The silicon substrate has opposite front and back surfaces. A first trench and a convex portion are formed on the back surface along a first direction. The first doped layer is stacked on the convex portion. The first doped layer includes a first sub-doped layer and a second sub-doped layer stacked on top of each other. The first sub-doped layer is stacked on the convex portion. The second sub-doped layer is stacked on the side of the first sub-doped layer away from the silicon substrate. The first insulating layer is stacked on the second sub-doped layer. The second doped layer is stacked in the first trench. The second doped layer has a polarity opposite to that of the first doped layer. The conduction type of the conductive contact structure is opposite to that of the first doped layer. The conductive contact structure includes a protruding portion that extends along the thickness direction of the silicon substrate. The protruding portion is at least partially disposed in the first trench. Only partial regions of the first doped layer and only partial regions of the second doped layer are respectively at least electrically connected to the protruding portion. The thickness of the protruding portion in the thickness direction is greater than the total thickness of the convex portion, the first doped layer, and the first insulating layer.

[0005] Furthermore, the conductive contact structure further includes a covering portion that is stacked on the first insulating layer. One end of the protruding portion away from the first trench is connected to the covering portion.

[0006] Furthermore, the conductive contact structure has the same conduction type as the second doped layer and is integrally continuous.

[0007] Further, the back-contact battery further includes a first dielectric layer, a second dielectric layer, and a third dielectric layer. The first dielectric layer is located between the first doped layer and the silicon substrate;

[0008] The third dielectric layer is located between the second doped layer and the silicon substrate;

[0009] The second dielectric layer is at least partially disposed in the first trench and fits on the sidewall of the convex portion.

[0010] Further, the second dielectric layer extends in the thickness direction away from the silicon substrate, and the second dielectric layer is at least partially electrically connected to the first doped layer.

[0011] Further, the back-contact battery further includes an insulating dielectric layer. The insulating dielectric layer is connected to one end of the second dielectric layer away from the silicon substrate. At least a part of the side of the insulating dielectric layer close to the convex portion is connected to the first doped layer and connected to the first insulating layer.

[0012] Further, the width of the insulating dielectric layer in the first direction is greater than the width of the second dielectric layer.

[0013] Further, the protruding portion further includes a first side and a second side disposed along the thickness direction. The first side is the side close to the convex portion, and the first side contacts the second dielectric layer. The second side is the side close to the first trench.

[0014] Further, the back-contact battery further includes a second insulating layer. The second insulating layer includes a first insulating portion, a second insulating portion, and a third insulating portion connected together in sequence. The first insulating portion is stacked on the covering portion. The second insulating portion is disposed on the side of the second side close to the first trench. The third insulating portion is stacked on the second doped layer.

[0015] Further, the first doped layer further includes a protruding portion extending above the first trench in the first direction, and the second dielectric layer surrounds the protruding portion.

[0016] Further, the thickness of the first sub-doped layer in the thickness direction is greater than the thickness of the second sub-doped layer.

[0017] Further, the thickness of the first sub-doped layer in the thickness direction is 50 nm - 300 nm;

[0018] The thickness of the second sub-doped layer in the thickness direction is 30 nm - 200 nm.

[0019] Further, the first doping layer further includes a first inner expansion layer formed within the convex portion, and the second doping layer further includes a second inner expansion layer formed within the first trench.

[0020] Further, the first doping layer further includes a first barrier layer, and the first barrier layer is stacked between the first sub-doping layer and the second sub-doping layer.

[0021] Further, in the thickness direction, the thickness of the first barrier layer is less than the thickness of the first dielectric layer.

[0022] Further, the second doping layer includes a third sub-doping layer and a fourth sub-doping layer stacked on top of each other. The third sub-doping layer is stacked on the first trench, and the fourth sub-doping layer is stacked on the side of the third sub-doping layer away from the silicon substrate.

[0023] Further, the second doping layer further includes a second barrier layer, and the second barrier layer is stacked between the third sub-doping layer and the fourth sub-doping layer.

[0024] The battery string provided by the embodiment of the present application includes a back-contact battery as described in any one of the above embodiments.

[0025] The battery module provided by the embodiment of the present application includes the battery string as described in the above embodiment.

[0026] The photovoltaic system provided by the embodiment of the present application includes the battery module as described in the above embodiment.

[0027] In the back-contact battery, battery string, battery module, and photovoltaic system according to the embodiments of the present application, the back-contact battery includes a silicon substrate, a first doped layer, a first insulating layer, a second doped layer, and a conductive contact structure. The silicon substrate has opposite front and back surfaces, and a first trench and a protrusion are formed on the back surface and arranged along a first direction. The first doped layer is stacked on the protrusion. The first doped layer includes a first sub-doped layer and a second sub-doped layer stacked on top of each other. The first sub-doped layer is stacked on the protrusion, and the second sub-doped layer is stacked on the side of the first sub-doped layer away from the silicon substrate. The first insulating layer is stacked on the second sub-doped layer. The second doped layer is stacked in the first trench. The second doped layer has a polarity opposite to that of the first doped layer. The conductive type of the conductive contact structure is opposite to that of the first doped layer. The conductive contact structure includes a protruding portion that extends along the thickness direction of the silicon substrate. The protruding portion is at least partially disposed in the first trench. Only partial regions of the first doped layer and only partial regions of the second doped layer are respectively electrically connected to the protruding portion at least. The thickness of the protruding portion in the thickness direction is greater than the total thickness of the protrusion, the first doped layer, and the first insulating layer. In this way, electrical energy can be released between the first doped layer and the second doped layer through the conductive contact structure. The conductive contact structure can serve as a heat dissipation point, reducing or even eliminating the influence of hot spots, and improving the power generation efficiency and safety of the back-contact battery. At the same time, the relatively large thickness of the protruding portion in the thickness direction enables the protruding portion to be electrically connected to the first sub-doped layer and the second sub-doped layer, forming multiple leakage points and further improving safety. In addition, the conductive contact structure can have the same conductive type as the second doped layer and be integrally continuous, simplifying the manufacturing process of the back-contact battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic cross-sectional structure diagram of a back-contact battery according to an embodiment of the present application;

[0029] Figure 2 is another schematic cross-sectional structure diagram of a back-contact battery according to an embodiment of the present application;

[0030] Figure 3 is still another schematic cross-sectional structure diagram of a back-contact battery according to an embodiment of the present application;

[0031] Figure 4 is yet another schematic cross-sectional structure diagram of a back-contact battery according to an embodiment of the present application;

[0032] Figure 5 is yet another schematic cross-sectional structure diagram of a back-contact battery according to an embodiment of the present application;

[0033] Figure 6 is yet another schematic cross-sectional structure diagram of a back-contact battery according to an embodiment of the present application;

[0034] Figure 7It is a schematic plan view of a back-contact battery according to an embodiment of the present application;

[0035] Figure 8 It is a schematic structural view of a battery module according to an embodiment of the present application;

[0036] Figure 9 It is a schematic structural view of a photovoltaic system according to an embodiment of the present application.

[0037] Description of main element symbols:

[0038] Back-contact battery 100, silicon substrate 10, front side 11, back side 12, first groove 121, convex portion 122, second groove 123, first doping layer 20, first sub-doping layer 21, second sub-doping layer 22, first inner diffusion layer 23, first blocking layer 24, protruding portion 25, retracted region 26, second doping layer 30, second inner diffusion layer 31, third sub-doping layer 32, fourth sub-doping layer 33, second blocking layer 34, first insulating layer 40, conductive contact structure 50, protruding part 51, first side 511, second side 512, covering part 52, insulating dielectric layer 60, second insulating layer 70, first insulating part 71, second insulating part 72, third insulating part 73, first dielectric layer 81, second dielectric layer 82, third dielectric layer 83, main grid 91, sub-grid 92, fine grid 93, battery string 200, battery module 300, photovoltaic system 400. Detailed implementation manners

[0039] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. The examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals indicate the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the accompanying drawings are exemplary only for explaining the present application and should not be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0040] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present application.

[0041] In addition, 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 quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of this application, "a plurality of" means two or more unless otherwise specifically defined.

[0042] In the description of this application, it should be noted that, unless otherwise clearly defined and limited, the terms "mounted", "connected" and "coupled" should be construed in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection, an electrical connection or a connection capable of mutual communication; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application may be understood according to specific circumstances.

[0043] In this application, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

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

[0045] In the related art, back-contact cells are provided with two doped layers having opposite conductivity types on the back surface of the cell. The two doped layers with opposite conductivity types are completely isolated from each other, which makes the back-contact cell have a relatively high reverse breakdown voltage, and further causes a relatively high hot-spot risk in photovoltaic modules including existing back-contact cells during actual operation. Preparing a conductor will increase the manufacturing cost and processes of the back-contact cell. At the same time, the conductivity efficiency of the conductor is often poor. In the present application, the conductive contact structure can serve as a heat dissipation point, reducing or even eliminating the influence of hot spots, and improving the power generation efficiency and safety of the back-contact cell. At the same time, the thickness of the protruding portion in the thickness direction is relatively large, so that the protruding portion can be electrically connected to the first sub-doped layer and the second sub-doped layer, forming a plurality of leakage points, further improving safety. In addition, the conductive contact structure can have the same conductivity type as the second doped layer and be integrally continuous, simplifying the manufacturing process of the back-contact cell.

[0046] Embodiment 1

[0047] Please refer to Figure 1 、 Figure 2 and Figure 3 . The back-contact cell 100 provided in the present application includes a silicon substrate 10, a first doped layer 20, a first insulating layer 40, a second doped layer 30, and a conductive contact structure 50. The silicon substrate 10 has opposite front surface 11 and back surface 12. A first groove 121 and a convex portion 122 are formed on the back surface 12 and arranged along a first direction. The first doped layer 20 is stacked on the convex portion 122. The first doped layer 20 includes a first sub-doped layer 21 and a second sub-doped layer 22 stacked on each other. The first sub-doped layer 21 is stacked on the convex portion 122. The second sub-doped layer 22 is stacked on the side of the first sub-doped layer 21 away from the silicon substrate 10. The first insulating layer 40 is stacked on the second sub-doped layer 22. The second doped layer 30 is stacked in the first groove 121. The second doped layer 30 has a polarity opposite to that of the first doped layer 20. The conductivity type of the conductive contact structure 50 is opposite to that of the first doped layer 20. The conductive contact structure 50 includes a protruding portion 51. The protruding portion 51 extends along the thickness direction of the silicon substrate 10. The protruding portion 51 is at least partially arranged in the first groove 121. Only partial regions of the first doped layer 20 and only partial regions of the second doped layer 30 are respectively at least electrically connected to the protruding portion 51. The thickness of the protruding portion 51 in the thickness direction is greater than the total thickness of the convex portion 122, the first doped layer 20, and the first insulating layer 40.

[0048] In this embodiment, the front surface 11 of the silicon substrate 10 is used to receive light, and a first doping layer 20 and a second doping layer 30 are formed on the back surface 12 of the silicon substrate 10. On the back surface 12 of the silicon substrate 10, the first trench 121 and the convex portion 122 are arranged along the first direction, and the first doping layer 20 and the second doping layer 30 disposed in the convex portion 122 and the first trench 121 respectively are also arranged along the first direction to form a photocurrent.

[0049] In addition, in this embodiment, a conductive contact structure 50 is further formed between the first doping layer 20 and the second doping layer 30. The conductive type of the conductive contact structure 50 is opposite to that of the first doping layer 20 and the same as that of the second doping layer 30. The protruding portion 51 of the conductive contact structure 50 can protrude from within the first trench 121. The portion of the protruding portion 51 located within the first trench 121 can be electrically connected to the second doping layer 30. At the same time, the protruding portion 51 extends upward along the thickness direction, and the thickness of the protruding portion 51 in the thickness direction is greater than the total thickness of the convex portion 122, the first doping layer 20, and the first insulating layer 40. In this way, the protruding portion 51 can be electrically contacted with the first sub-doping layer 21 and the second sub-doping layer 22 respectively. That is to say, the protruding portion 51 can form local leakage points at the contact positions with the first sub-doping layer 21 and the second sub-doping layer 22 respectively to electrically connect the first doping layer 20 and the second doping layer 30 to form a built-in diode with a lower reverse breakdown voltage, so that the back contact battery 100 has a lower reverse breakdown voltage when being blocked, eliminating the influence of hot spots.

[0050] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, the first doping layer 20 further includes a first blocking layer 24, and the first blocking layer 24 is stacked between the first sub-doping layer 21 and the second sub-doping layer 22.

[0051] Specifically, a first blocking layer 24 can be further disposed between the first sub-doping layer 21 and the second sub-doping layer 22. The first blocking layer 24 is stacked on the first sub-doping layer 21, and the second sub-doping layer 22 is stacked on the side of the first blocking layer 24 away from the first sub-doping layer 21. The widths of the first sub-doping layer 21, the first blocking layer 24, and the second sub-doping layer 22 in the first direction can be the same, so that the protruding portion 51 can be electrically connected to the first sub-doping layer 21, the first blocking layer 24, and the second sub-doping layer 22 at the same time. It can be understood that the thickness of the protruding portion 51 in the thickness direction is greater than the total thickness of the convex portion 122, the first sub-doping layer 21, the first blocking layer 24, the second sub-doping layer 22, and the first insulating layer 40 to ensure that the protruding portion 51 can stably form leakage points with the first sub-doping layer 21 and the second sub-doping layer 22 respectively, further improving safety.

[0052] Furthermore, only partial regions of the first doping layer 20 and only partial regions of the second doping layer 30 are electrically connected to the protruding portion 51 respectively. That is to say, the protruding portion 51 can be in electrical contact with partial positions of the first doping layer 20 and the second doping layer 30 respectively. Other regions of the first doping layer 20 and the second doping layer 30 can be physically isolated through the design of the first trench 121 and the convex portion 122, so as to avoid a large leakage current when the back contact battery 100 is in normal operation due to the full contact between the first doping layer 20 and the second doping layer 30 through the conductive contact structure 50, resulting in a low working efficiency of the back contact battery 100. In addition, the first sub-doping layer 21 and the second sub-doping layer 22 can also serve as insurance for each other. When one of the first sub-doping layer 21 or the second sub-doping layer 22 is damaged or short-circuited, the other sub-doping layer can still form a leakage point with the second doping layer 30 through the protruding portion 51, thereby further improving the safety.

[0053] In one embodiment, the first trenches 121 and the convex portions 122 are alternately arranged along the first direction, and the first trenches 121 and the convex portions 122 extend along the second direction. That is to say, both the first doping layer 20 and the second doping layer 30 are also alternately arranged in strip shapes along the first direction and extend along the second direction. The second direction is perpendicular to the first direction and is located in the horizontal direction. That is to say, the plane formed by the first direction and the second direction is perpendicular to the thickness direction of the silicon substrate 10.

[0054] Please refer to Figure 3 , in this embodiment, a second trench 123 extending along the second direction can also be formed on the back surface 12. The second trench 123 is arranged between the first trenches 121 and the convex portions 122 to physically isolate the first doping layer 20 and the second doping layer 30. In this embodiment, the second trench 123 can be arranged at any position between any adjacent first trenches 121 and convex portions 122, and specific details are not limited herein. In one example, the first trench 121 can be further excavated into the silicon substrate 10 to form a deeper second trench 123. In another example, the convex portion 122 can be further excavated into the silicon substrate 10 to form a second trench 123 with a depth deeper than that of the first trench 121. The specific setting positions and distribution rules of the trenches are not limited herein to meet various requirements.

[0055] Please refer to Figure 2 and Figure 4, in the present application, both the first doping layer 20 and the second doping layer 30 can be a P-type doping layer and an N-type doping layer respectively, as long as the polarities of the two are opposite. For example, in some embodiments, the first doping layer 20 can be a P-type polysilicon layer, a P-type amorphous silicon layer, or a P-type microcrystalline silicon layer, and specific types are not limited herein. Similarly, the second doping layer 30 can be an N-type polysilicon layer, an N-type amorphous silicon layer, or an N-type microcrystalline silicon layer, and specific types are not limited herein. When the first doping layer 20 is a P-type doping layer and the second doping layer 30 is an N-type doping layer, a P-type main gate 91 can also be provided corresponding to the convex portion 122, and an N-type sub-gate 92 can be provided in the first trench 121. Of course, in some other embodiments, it can also be that a P-type fine gate 93 is provided in the convex portion 122 and an N-type sub-gate 92 is provided in the first trench 121, and specific arrangements are not limited herein.

[0056] Of course, in other embodiments, both the first doping layer 20 and the second doping layer 30 can also be an N-type doping layer and a P-type doping layer respectively, and specific types are not limited herein.

[0057] In the embodiments of the present application, the widths of the convex portion 122 and the first trench 121 in the first direction and the ratio of the convex portion 122 to the first trench 121 are not limited, as long as the requirements are met. In addition, in the embodiments of the present application, the height ratio between the convex portion 122 and the first trench 121 is also not limited to meet different requirements.

[0058] Embodiment Two

[0059] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, the conductive contact structure 50 further includes a covering portion 52. The covering portion 52 is stacked on the first insulating layer 40, and one end of the protruding portion 51 away from the first trench 121 is connected to the covering portion 52.

[0060] In this way, the protruding portion 51 and the covering portion 52 can be integrally formed, thereby simplifying the preparation difficulty of the conductive contact structure 50. At the same time, the covering portion 52 can cooperate with the protruding portion 51 to wrap and cover one side of the first doping layer 20 and the first insulating layer 40, avoiding the situation that the protruding distance of the protruding portion 51 is insufficient, resulting in no leakage point formed between the protruding portion 51 and the first sub-doping layer 21 and the second sub-doping layer 22, and improving the manufacturing efficiency of the back-contact battery 100.

[0061] Specifically, the protruding portion 51 and the covering portion 52 of the conductive contact structure 50 can be an integral structure to reduce the etching accuracy and the etching difficulty. At the same time, it can also ensure that the protruding portion 51 corresponding to the first doping layer 20 can cover the first sub-doping layer 21 and the second sub-doping layer 22 to form a local electrical connection state.

[0062] Embodiment Three

[0063] Please refer to Figure 1 and Figure 2 In some alternative embodiments, the conductive contact structure 50 has the same conductivity type as and is integrally continuous with the second doped layer 30.

[0064] In this way, the entire conductive contact structure 50 has the same conductivity type as and is integrally continuous with the second doped layer 30. That is to say, essentially, the conductive contact structure 50 and the second doped layer 30 can be the same material layer. In this way, the conductive contact structure 50 and the second doped layer 30 can be manufactured simultaneously based on the same process, so as to reduce the manufacturing difficulty of the conductive contact structure 50, simplify the manufacturing process of the conductive contact structure 50, and improve the manufacturing efficiency of the back contact battery 100.

[0065] In addition, in the present application, the first doped layer 20 can be a P-type doped layer, and the second doped layer 30 can be an N-type doped layer. That is to say, the protruding portion 51 and the covering portion 52 of the conductive contact structure 50 can also both be N-type doped layers.

[0066] Embodiment 4

[0067] Please refer to Figure 1 and Figure 2 In some alternative embodiments, the back contact battery 100 further includes a first dielectric layer 81, a second dielectric layer 82, and a third dielectric layer 83. The first dielectric layer 81 is located between the first doped layer 20 and the silicon substrate 10;

[0068] The third dielectric layer 83 is located between the second doped layer 30 and the silicon substrate 10;

[0069] The second dielectric layer 82 is at least partially disposed in the first trench 121 and fits on the sidewall of the convex portion 122.

[0070] In this embodiment, the first dielectric layer 81, the second dielectric layer 82, and the third dielectric layer 83 can be tunneling oxide layers. The tunneling oxide layer plays a role in the tunneling effect, enabling carriers to be transmitted through the thin tunneling oxide layer, while providing a good surface passivation effect, reducing the recombination rate, and thus improving the efficiency of the back contact battery 100.

[0071] In the implementation manner of the present application, the specific materials of the first dielectric layer 81, the second dielectric layer 82, and the third dielectric layer 83 are not limited to meet different requirements. At the same time, the materials of the first dielectric layer 81, the second dielectric layer 82, and the third dielectric layer 83 can be the same or different. Please refer to Figure 1 The materials of the first dielectric layer 81, the second dielectric layer 82, and the third dielectric layer 83 are the same; Please refer to Figure 2, the materials of the first dielectric layer 81, the second dielectric layer 82, and the third dielectric layer 83 are different. When the materials of the first dielectric layer 81, the second dielectric layer 82, and the third dielectric layer 83 are different, the first dielectric layer 81, the second dielectric layer 82, and the third dielectric layer 83 are discontinuous structures.

[0072] Embodiment Five

[0073] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, the second dielectric layer 82 extends in the thickness direction away from the silicon substrate 10, and the second dielectric layer 82 is at least partially electrically connected to the first doped layer 20.

[0074] In this way, both the second dielectric layer 82 and the protruding portion 51 can be partially disposed in the first trench 121 and extend along the thickness direction of the silicon substrate 10. That is to say, the protruding portion 51 can be electrically connected to the first doped layer 20 through the second dielectric layer 82.

[0075] Specifically, the second dielectric layer 82 can cover all of the first sub-doped layer 21 and the first barrier layer 24 on the side and contact a part of the second sub-doped layer 22. In this way, the contact surfaces between the protruding portion 51 and the second dielectric layer 82 are all effective electrical contact surfaces.

[0076] Embodiment Six

[0077] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, the back-contact battery 100 further includes an insulating dielectric layer 60. The insulating dielectric layer 60 is connected to one end of the second dielectric layer 82 away from the silicon substrate 10. At least a part of the side of the insulating dielectric layer 60 close to the convex portion 122 is connected to the first doped layer 20 and the first insulating layer 40.

[0078] In this embodiment, the insulating dielectric layer 60 and the second dielectric layer 82 are flush on the side close to the protruding portion 51, so that the side morphology of the protruding portion 51 close to the convex portion 122 is flat and regular, which is beneficial to reducing the manufacturing difficulty of the conductive contact structure 50 and improving the yield of the back-contact battery 100.

[0079] Embodiment Seven

[0080] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, the width of the insulating dielectric layer 60 in the first direction is greater than the width of the second dielectric layer 82.

[0081] Thus, the insulating dielectric layer 60 can cooperate with the first insulating layer 40 to cover and shield the first doped layer 20. At the same time, the insulating dielectric layer 60 can also partially extend into the inside of the protruding portion 51 along the first direction, so that the first doped layer 20 can be electrically connected to the protruding portion 51, while avoiding contact with the covering portion 52, thereby improving the stability of the conductive contact structure 50.

[0082] Embodiment VIII

[0083] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, the protruding portion 51 further includes a first side edge 511 and a second side edge 512 arranged in the thickness direction. The first side edge 511 is the side closer to the convex portion 122, the first side edge 511 contacts the second dielectric layer 82, and the second side edge 512 is the side closer to the first trench 121.

[0084] In this embodiment, the side of the insulating dielectric layer 60 close to the first trench 121 protrudes from the first side edge 511. The top of the first side edge 511 is the insulating dielectric layer 60, and the bottom of the first side edge 511 extends into the first trench 121. The first side edge 511 fits on the surface of the second dielectric layer 82, and the first doped layer 20 forms a leakage point at the position of the first side edge 511 through the second dielectric layer 82.

[0085] Embodiment IX

[0086] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, the back contact battery 100 further includes a second insulating layer 70. The second insulating layer 70 includes a first insulating portion 71, a second insulating portion 72, and a third insulating portion 73 that are connected together in sequence. The first insulating portion 71 is stacked on the covering portion 52, the second insulating portion 72 is arranged on the side of the second side edge 512 close to the first trench 121, and the third insulating portion 73 is stacked on the second doped layer 30.

[0087] Thus, the second insulating layer 70 can protect the covering portion 52, the protruding portion 51, and the second doped layer 30 in sequence through the first insulating portion 71, the second insulating portion 72, and the third insulating portion 73, avoiding the exposure of the conductive contact structure 50 and the second doped layer 30.

[0088] In this embodiment, the second insulating layer 70 may be a passivation film layer. When the first doping layer 20 is a P-type doping layer and the second doping layer 30 is an N-type doping layer, the surface roughness of the second doping layer 30 in contact with the first insulating portion 71 is greater than that of the first doping layer 20 in contact with the first insulating portion 71. This can make the bonding force between the first insulating portion 71 and the second doping layer 30 greater than the bonding force between the first insulating portion 71 and the first doping layer 20, thereby effectively preventing the first solder joint from detaching during welding and improving the reliability of welding.

[0089] In some embodiments, the passivation film layer may include at least one of a silicon nitride film layer, an aluminum oxide film layer, a silicon oxynitride film layer, an intrinsic amorphous silicon film layer, and a TCO film layer, and specific details are not limited herein.

[0090] Embodiment Ten

[0091] Please refer to Figure 1 and Figure 2 In some alternative embodiments, the first doping layer 20 further includes a protruding portion 25 extending above the first trench 121 in the first direction, and the second dielectric layer 82 surrounds the protruding portion 25.

[0092] In this way, the first doping layer 20 can form a larger contact area with the protruding portion 51 through the protruding portion 25, thereby improving the conduction efficiency and quickly eliminating the influence of hot spots.

[0093] In the embodiment of the present application, the shape of the protruding portion 25 is not limited to meet different requirements. For example, the end portions of the protruding portion 25 close to the first trench 121 intersect to form tips, and the closer to the first trench 121, the sharper the end portions of the protruding portion 25. Again, the end portions of the protruding portion 25 close to the first trench 121 may be rectangular. At this time, the width of the second dielectric layer 82 in the thickness direction of the silicon substrate 10 is smaller than the width of the second dielectric layer 82 in the first direction, so that the first sub-doping layer 21 is closer to the protruding portion 51 in the thickness direction, and the first sub-doping layer 21 can form a leakage point at this position to further improve safety.

[0094] Please combine Figure 2, in some embodiments, the second dielectric layer 82 includes a first region 821 and a second region 822 connected together. The first region 821 extends along a first direction, and the second region 822 extends along the thickness direction. The top of the second region 822 is the insulating dielectric layer 60. On both sides of the second region 822 are respectively the second doped layer 30 and the first side 511. The bottom of the second region 822 is connected to the first region 821. At least a part of the top of the first region 821 is in contact connection with the first sub-doped layer 21, and at least a part of the bottom of the first region 821 is in contact connection with the protrusion 51. That is to say, leakage points can also be formed at the position of the first region 821 to eliminate hot spots.

[0095] Specifically, the side surface of the protruding part 25 along the first direction is the second region 822, and the bottom surface of the protruding part 25 along the thickness direction is the first region 821. The first region 821 and the second region 822 are provided with a part of the second dielectric layer 82. Or rather, a part of the second dielectric layer 82 can be arranged in the first region 821, and another part of the second dielectric layer 82 can be arranged in the second region 822.

[0096] In some embodiments, the thickness of the first region 821 in the thickness direction is thinner than the width of the second region 822 in the first direction. That is to say, the distance between the first doped layer 20 and the protrusion 51 is closer in the first region 821, so that the leakage points formed through the first region 821 have higher conduction efficiency and better safety.

[0097] Please refer to Figure 5 , in some embodiments, the first doped layer 20 further includes a retracted region 26 that retracts above the convex portion 122 along the first direction, and the second dielectric layer 82 is correspondingly arranged in the retracted region 26. In this way, the first doped layer 20 can form a larger contact area with the protrusion 51 through the retracted region 26, thereby improving the conduction efficiency and quickly eliminating the influence of hot spots.

[0098] Embodiment XI

[0099] Please refer to Figure 1 and Figure 2 , in some alternative embodiments, the thickness of the first sub-doped layer 21 in the thickness direction is greater than the thickness of the second sub-doped layer 22.

[0100] In this way, the first sub-doped layer 21 closer to the silicon substrate 10 has a greater thickness than the second sub-doped layer 22, making the silicon substrate 10 more stable, with better passivation effect, better refractive index, and higher light reception efficiency.

[0101] In other embodiments, the first doping layer 20 may further include a plurality of other sub-doping layers, all of the sub-doping layers are stacked, and a first blocking layer 24 is formed between different sub-doping layers. In the embodiments of the present application, the number of sub-doping layers is not limited, and it is only necessary to ensure that the sub-doping layer closer to the silicon substrate 10 is thicker to meet different requirements.

[0102] Embodiment Twelve

[0103] Please refer to Figure 1 and Figure 2 In some alternative embodiments, the thickness of the first sub-doping layer 21 in the thickness direction is 50 nm - 300 nm; the thickness of the second sub-doping layer 22 in the thickness direction is 30 nm - 200 nm.

[0104] Exemplarily, the thickness of the first sub-doping layer 21 in the thickness direction can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm, 250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm. The thickness of the second sub-doping layer 22 in the thickness direction can be 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm. The thickness settings of the first sub-doping layer 21 and the second sub-doping layer 22 in the thickness direction within this range ensure the basic functions of the first doping layer 20 and reduce the preparation difficulty.

[0105] In the embodiments of the present application, the specific thicknesses of the first sub-doping layer 21 and the second sub-doping layer 22 are not limited, and it is only necessary that the thickness of the first sub-doping layer 21 in the thickness direction is greater than the thickness of the second sub-doping layer 22.

[0106] In one example, the thickness of the first sub-doping layer 21 in the thickness direction can be 200 nm, and at the same time, the thickness of the second sub-doping layer 22 in the thickness direction can be 100 nm. In this way, the first doping layer 20 can be maintained within a suitable thickness range, and on the premise of being thin and light, it can cooperate with the protruding portion 51 to increase the number of leakage points and improve the safety of the back-contact battery 100.

[0107] Embodiment Thirteen

[0108] Please refer to Figure 1 and Figure 2, in some alternative embodiments, the first doping layer 20 further includes a first inner expansion layer 23 formed within the convex portion 122, and the second doping layer 30 further includes a second inner expansion layer 31 formed within the first trench 121.

[0109] In this way, the first doping layer 20 can form the first inner expansion layer 23 on the side of the first dielectric layer 81 close to the silicon substrate 10 toward the silicon substrate 10 through a diffusion process, and the second doping layer 30 can form the second inner expansion layer 31 on the side of the third dielectric layer 83 close to the silicon substrate 10 toward the silicon substrate 10 through a diffusion process. The combination of the inner expansion layer with the tunneling oxide layer and the polysilicon layer further improves the efficiency and stability of the battery.

[0110] In this embodiment, the thickness of the protruding portion 51 in the thickness direction of the silicon substrate 10 is greater than the total thickness of the convex portion 122, the first inner expansion layer 23, the first doping layer 20, and the first insulating layer 40. That is to say, the side of the first inner expansion layer 23 close to the first trench 121 is in contact connection with the second dielectric layer 82, and the second dielectric layer 82 is electrically connected to the protruding portion 51. The first inner expansion layer 23 and the protruding portion 51 can form a new leakage point, and the electrical energy can be released between the first inner expansion layer 23 and the second doping layer 30 through the protruding portion 51 to reduce or even eliminate the influence of hot spots, further improving the power generation efficiency and safety of the back contact battery 100.

[0111] Embodiment Fourteen

[0112] Please refer to Figure 6 , in some alternative embodiments, the second doping layer 30 includes a third sub-doping layer 32 and a fourth sub-doping layer 33 stacked, the third sub-doping layer 32 is stacked on the first trench 121, and the fourth sub-doping layer 33 is stacked on the side of the third sub-doping layer 32 away from the silicon substrate 10.

[0113] In some alternative embodiments, the second doping layer 30 further includes a second barrier layer 34, and the second barrier layer 34 is stacked between the third sub-doping layer 32 and the fourth sub-doping layer 33.

[0114] Specifically, a second barrier layer 34 can also be provided between the third sub-doping layer 32 and the fourth sub-doping layer 33. The second barrier layer 34 is stacked on the third sub-doping layer 32, and the fourth sub-doping layer 33 is stacked on the side of the second barrier layer 34 away from the third sub-doping layer 32. The widths of the third sub-doping layer 32, the second barrier layer 34, and the fourth sub-doping layer 33 in the first direction can be the same, so that the protruding portion 51 can be electrically connected to the third sub-doping layer 32, the second barrier layer 34, and the fourth sub-doping layer 33 at the same time.

[0115] Furthermore, the first blocking layer 24 and the second blocking layer 34 play a blocking role, forming a doping concentration difference between the two sub-layer doping layers, which can further improve the passivation effect of the passivated contact structure of the back contact battery 100 and enhance the efficiency of the back contact battery 100. In this embodiment, the range of the doping concentration of the doping layers on both sides of the first blocking layer 24 and the second blocking layer 34 is not limited to meet different requirements.

[0116] Still further, when the conductive contact structure 50 has the same conductive type as and is integrally continuous with the second doping layer 30, the second blocking layer 34 can extend from the second doping layer 30 along the protruding portion 51 and the covering portion 52, so as to divide the protruding portion 51 and the covering portion 52 into two doping layers as well. In this way, during the preparation process, the conductive contact structure 50 and the second doping layer 30 can be prepared together, saving the preparation steps and improving the production efficiency.

[0117] Even further, in the thickness direction, the thickness of the first blocking layer 24 is less than the thickness of the first dielectric layer 81. In this way, voids are provided in the first blocking layer 24, thereby adjusting the doping concentrations of the first sub-doping layer 21 and the second sub-doping layer 22.

[0118] Embodiment Fifteen

[0119] Please refer to Figure 7 and Figure 8 , the battery string 200 provided by the embodiment of the present application includes the back contact battery 100 of any one of the above embodiments.

[0120] In the back-contact battery 100 and the battery string 200 according to the embodiments of the present application, the back-contact battery 100 includes a silicon substrate 10, a first doping layer 20, a first insulating layer 40, a second doping layer 30, and a conductive contact structure 50. The silicon substrate 10 has opposite front surface 11 and back surface 12. A first groove 121 and a convex portion 122 are formed on the back surface 12 and arranged along a first direction. The first doping layer 20 is stacked on the convex portion 122. The first doping layer 20 includes a first sub-doping layer 21 and a second sub-doping layer 22 which are stacked. The first sub-doping layer 21 is stacked on the convex portion 122, and the second sub-doping layer 22 is stacked on the side of the first sub-doping layer 21 away from the silicon substrate 10. The first insulating layer 40 is stacked on the second sub-doping layer 22. The second doping layer 30 is stacked in the first groove 121. The second doping layer 30 has a polarity opposite to that of the first doping layer 20. The conductive type of the conductive contact structure 50 is opposite to that of the first doping layer 20. The conductive contact structure 50 includes a protruding portion 51. The protruding portion 51 extends along the thickness direction of the silicon substrate 10. The protruding portion 51 is at least partially arranged in the first groove 121. Only partial regions of the first doping layer 20 and only partial regions of the second doping layer 30 are respectively electrically connected to the protruding portion 51 at least. The thickness of the protruding portion 51 in the thickness direction is greater than the total thickness of the convex portion 122, the first doping layer 20, and the first insulating layer 40. Thus, electrical energy can be released between the first doping layer 20 and the second doping layer 30 through the conductive contact structure 50. The conductive contact structure 50 can serve as a heat dissipation point, reducing or even eliminating the influence of hot spots, and improving the power generation efficiency and safety of the back-contact battery 100. At the same time, the protruding portion 51 has a relatively large thickness in the thickness direction, enabling the protruding portion 51 to be electrically connected to the first sub-doping layer 21 and the second sub-doping layer 22 to form multiple leakage points, further improving safety. In addition, the conductive contact structure 50 can have the same conductive type as the second doping layer 30 and be integrally continuous, simplifying the manufacturing process of the back-contact battery 100.

[0121] Specifically, the first doping layer 20 and the second doping layer 30 have opposite polarities. The first doping layer 20 and the second doping layer 30 are P-type doping and N-type doping respectively. In some embodiments, P-type doping refers to doping group III elements, including elements such as boron, aluminum, gallium, indium, thallium, etc.; N-type doping refers to doping group V elements, including elements such as nitrogen, phosphorus, arsenic, antimony, bismuth, etc., and specific details are not limited herein.

[0122] In addition, in some embodiments, the first doping layer 20 and the second doping layer 30 can also be of composite doping. For example, N-type doping also includes a small amount of P-type doping elements. Among them, the content of N-type doping elements in the second doping layer 30 is higher than 20% of the content of P-type doping elements to ensure the opposite polarity to the first doping layer 20.

[0123] Further, the conductive contact structure 50 has the same conductivity type as the second doped layer 30 and is opposite to the conductivity type of the first doped layer 20 at the same time. The conductive contact structure 50 is not a doped region. Therefore, the conductive contact structure 50 has an N-type doping, and the main conductive carriers are electrons. That is to say, for N-type doping, electrons are the majority carriers, for P-type doping, holes are the majority carriers. The conductive contact structure 50 and the N-type doped region are of the same type, and of different conductivity types from the P-type doped region.

[0124] Exemplarily, in some embodiments, the first doped layer 20 may be a P-type polysilicon layer, a P-type amorphous silicon layer, or a P-type microcrystalline silicon layer, and specific types are not limited herein. Similarly, the second doped layer 30 and the conductive contact structure 50 may be an N-type polysilicon layer, an N-type amorphous silicon layer, or an N-type microcrystalline silicon layer, and specific types are not limited herein.

[0125] In the embodiment of the present application, the battery string 200 may be formed by sequentially connecting a plurality of sheet-shaped back contact batteries 100 in series and connected by solder tapes and busbars. It can be understood that in the battery string 200, the battery string 200 may include two serially connected battery cells, three serially connected battery cells, or other more battery cells. The specific number of battery cells to be serially connected may be determined according to actual usage. In addition, in the embodiment of the present application, the size and type of the back contact battery 100 are not limited either. The specifications and sizes of adjacent battery cells may be the same or different to meet different requirements.

[0126] In the embodiment of the present application, the specific connection method of adjacent battery cells is not limited to meet different requirements. In one embodiment, at least a part of the edges of two adjacent battery cells are stacked together; in another embodiment, two adjacent battery cells may be spaced apart. The spacing between two adjacent battery cells is within a suitable range, which can avoid small operating space and difficult soldering caused by too small a spacing, and can also avoid wasting component space and increasing costs caused by too large a spacing.

[0127] Embodiment Sixteen

[0128] Please refer to Figure 7 and Figure 8 The battery module 300 provided by the embodiment of the present application includes the battery string 200 as described in the above embodiment.

[0129] In the back-contact battery 100, battery string 200, and battery module 300 according to the embodiments of the present application, the back-contact battery 100 includes a silicon substrate 10, a first doping layer 20, a first insulating layer 40, a second doping layer 30, and a conductive contact structure 50. The silicon substrate 10 has opposite front surface 11 and back surface 12. On the back surface 12, a first groove 121 and a protrusion 122 are formed along a first direction. The first doping layer 20 is stacked on the protrusion 122. The first doping layer 20 includes a stacked first sub-doping layer 21 and second sub-doping layer 22. The first sub-doping layer 21 is stacked on the protrusion 122. The second sub-doping layer 22 is stacked on a side of the first sub-doping layer 21 away from the silicon substrate 10. The first insulating layer 40 is stacked on the second sub-doping layer 22. The second doping layer 30 is stacked in the first groove 121. The second doping layer 30 has a polarity opposite to that of the first doping layer 20. The conductive type of the conductive contact structure 50 is opposite to that of the first doping layer 20. The conductive contact structure 50 includes a protruding portion 51. The protruding portion 51 extends along the thickness direction of the silicon substrate 10. The protruding portion 51 is at least partially disposed in the first groove 121. Only partial regions of the first doping layer 20 and only partial regions of the second doping layer 30 are respectively electrically connected to the protruding portion 51 at least. The thickness of the protruding portion 51 in the thickness direction is greater than the total thickness of the protrusion 122, the first doping layer 20, and the first insulating layer 40. Thus, electrical energy can be released between the first doping layer 20 and the second doping layer 30 through the conductive contact structure 50. The conductive contact structure 50 can serve as a heat dissipation point, reducing or even eliminating the influence of hot spots, and improving the power generation efficiency and safety of the back-contact battery 100. At the same time, the relatively large thickness of the protruding portion 51 in the thickness direction enables the protruding portion 51 to be electrically connected to the first sub-doping layer 21 and the second sub-doping layer 22, forming multiple leakage points and further improving safety. In addition, the conductive contact structure 50 can have the same conductive type as the second doping layer 30 and be integrally continuous, simplifying the manufacturing process of the back-contact battery 100.

[0130] In this embodiment, multiple back-contact batteries 100 in the battery module 300 can be connected in series in sequence to form the battery string 200, thereby achieving the series connection and current collection output of the current. For example, the connection of the battery cells can be achieved by setting solder tapes (busbars, interconnection bars), conductive backplates, etc.

[0131] It can be understood that in such an embodiment, the battery module 300 may further include a frame, a backplate, a photovoltaic glass, and a glue film. The glue film can be filled between the front surface 11 and the back surface 12 of the back-contact battery 100, the photovoltaic glass, adjacent battery cells, etc. As a filler, it can be a transparent colloid with good light transmission performance and aging resistance. For example, the glue film can adopt an EVA glue film or a POE glue film, and specific selection can be made according to actual situations without limitation herein.

[0132] The photovoltaic glass can be covered on the adhesive film on the front surface 11 of the back-contact battery 100. The photovoltaic glass can be ultra-white glass, which has a high light transmittance, high transparency, and excellent physical, mechanical, and optical properties. For example, the light transmittance of the ultra-white glass can reach more than 92%, and it can protect the back-contact battery 100 without significantly affecting the efficiency of the back-contact battery 100. At the same time, the adhesive film can bond the photovoltaic glass and the back-contact battery 100 together, and the presence of the adhesive film can seal and insulate the back-contact battery 100 and prevent water and moisture.

[0133] The backsheet can be attached to the adhesive film on the back surface 12 of the back-contact battery 100. The backsheet can protect and support the back-contact battery 100, and has reliable insulation, water resistance, and aging resistance. There are multiple choices for the backsheet, which can usually be tempered glass, plexiglass, aluminum alloy TPT composite adhesive film, etc., and its specific settings can be determined according to specific circumstances and are not limited here. The whole composed of the backsheet, the back-contact battery 100, the adhesive film, and the photovoltaic glass can be set on the frame. The frame is the main external support structure of the entire battery module 300 and can stably support and install the battery module 300. For example, the battery module 300 can be installed at the required installation position through the frame.

[0134] Example Seventeen

[0135] Please refer to Figure 8 and Figure 9 , the photovoltaic system 400 provided by the implementation mode of this application includes the battery module 300 as described in the above implementation mode.

[0136] In the back-contact battery 100, battery string 200, battery module 300, and photovoltaic system 400 according to the embodiments of the present application, the back-contact battery 100 includes a silicon substrate 10, a first doping layer 20, a first insulating layer 40, a second doping layer 30, and a conductive contact structure 50. The silicon substrate 10 has opposite front and back surfaces 11 and 12. A first groove 121 and a convex portion 122 are formed on the back surface 12 and arranged along a first direction. The first doping layer 20 is stacked on the convex portion 122. The first doping layer 20 includes a first sub-doping layer 21 and a second sub-doping layer 22 that are stacked. The first sub-doping layer 21 is stacked on the convex portion 122, and the second sub-doping layer 22 is stacked on the side of the first sub-doping layer 21 away from the silicon substrate 10. The first insulating layer 40 is stacked on the second sub-doping layer 22. The second doping layer 30 is stacked in the first groove 121. The second doping layer 30 has a polarity opposite to that of the first doping layer 20. The conductive type of the conductive contact structure 50 is opposite to that of the first doping layer 20. The conductive contact structure 50 includes a protruding portion 51 that extends along the thickness direction of the silicon substrate 10. The protruding portion 51 is at least partially disposed in the first groove 121. Only partial regions of the first doping layer 20 and only partial regions of the second doping layer 30 are respectively electrically connected to the protruding portion 51 at least. The thickness of the protruding portion 51 in the thickness direction is greater than the total thickness of the convex portion 122, the first doping layer 20, and the first insulating layer 40. Thus, electrical energy can be released between the first doping layer 20 and the second doping layer 30 through the conductive contact structure 50. The conductive contact structure 50 can serve as a heat dissipation point, reducing or even eliminating the influence of hot spots, and improving the power generation efficiency and safety of the back-contact battery 100. At the same time, the protruding portion 51 has a relatively large thickness in the thickness direction, enabling the protruding portion 51 to be electrically connected to the first sub-doping layer 21 and the second sub-doping layer 22 to form multiple leakage points, further improving safety. In addition, the conductive contact structure 50 can have the same conductive type as the second doping layer 30 and be integrally continuous, simplifying the manufacturing process of the back-contact battery 100.

[0137] In this embodiment, the photovoltaic system 400 can be applied in a photovoltaic power station, such as a ground power station, a rooftop power station, a water surface power station, etc., or can also be applied to devices or apparatuses that utilize solar energy for power generation, such as a user solar power supply, a solar street lamp, a solar vehicle, a solar building, and so on. Of course, it can be understood that the application scenarios of the photovoltaic system 400 are not limited thereto, that is to say, the photovoltaic system 400 can be applied in all fields that require solar power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system 400 can include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array can be an array combination of multiple battery modules 300. For example, multiple battery modules 300 can form multiple photovoltaic arrays. The photovoltaic arrays are connected to the combiner box, and the combiner box can combine the currents generated by the photovoltaic arrays. The combined current flows through the inverter and is converted into alternating current required by the commercial power grid and then connected to the commercial power grid to achieve solar power supply.

[0138] In the description of this specification, the descriptions with reference to terms such as "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0139] In addition, the above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A back-contact battery, characterized in that, Comprising: A silicon substrate having a front side and a back side opposite to each other, with a first trench and a convex portion formed on the back side and arranged in a first direction; A first doped layer stacked on the convex portion, the first doped layer including a first sub-doped layer and a second sub-doped layer stacked on each other, the first sub-doped layer being stacked on the convex portion, and the second sub-doped layer being stacked on the side of the first sub-doped layer away from the silicon substrate; A first insulating layer stacked on the second sub-doped layer; A second doped layer stacked in the first trench, the second doped layer having a polarity opposite to that of the first doped layer; A conductive contact structure, the conductive type of the conductive contact structure being opposite to that of the first doped layer, the conductive contact structure including a protruding portion extending along the thickness direction of the silicon substrate, the protruding portion being at least partially disposed in the first trench, only partial regions of the first doped layer and only partial regions of the second doped layer being respectively at least electrically connected to the protruding portion, and the thickness of the protruding portion in the thickness direction being greater than the total thickness of the convex portion, the first doped layer, and the first insulating layer.

2. The back contact battery according to claim 1, characterized in that, The conductive contact structure further includes a covering portion stacked on the first insulating layer, and one end of the protruding portion away from the first trench is connected to the covering portion.

3. The back-contact battery according to claim 2, wherein The conductive contact structure has the same conductive type as the second doped layer and is integrally continuous.

4. The back contact battery according to claim 2, characterized in that, The back contact battery further includes a first dielectric layer, a second dielectric layer, and a third dielectric layer, the first dielectric layer being located between the first doped layer and the silicon substrate; The third dielectric layer is located between the second doped layer and the silicon substrate; The second dielectric layer is at least partially disposed in the first trench and adheres to the side wall of the convex portion.

5. The back-contact battery according to claim 4, characterized in that, The second dielectric layer extends in the thickness direction away from the silicon substrate, and the second dielectric layer is at least partially electrically connected to the first doped layer.

6. The back-contact battery according to claim 5, wherein, The back contact battery further includes an insulating dielectric layer connected to one end of the second dielectric layer away from the silicon substrate, and at least a part of the side of the insulating dielectric layer close to the convex portion is connected to the first doped layer and the first insulating layer.

7. The back-contact battery according to claim 6, wherein, The width of the insulating dielectric layer in the first direction is greater than the width of the second dielectric layer.

8. The back contact battery according to claim 7, characterized in that, The protruding portion further includes a first side edge and a second side edge arranged along the thickness direction, the first side edge being the side close to the convex portion and contacting the second dielectric layer, and the second side edge being the side close to the first trench.

9. The back contact battery according to claim 8, wherein, The back contact battery further includes a second insulating layer, the second insulating layer including a first insulating portion, a second insulating portion, and a third insulating portion connected together in sequence, the first insulating portion being stacked on the covering portion, the second insulating portion being disposed on the side of the second side edge close to the first trench, and the third insulating portion being stacked on the second doped layer.

10. The back-contact battery according to claim 6, wherein The first doped layer further includes a protruding portion extending above the first trench in the first direction, and the second dielectric layer surrounds the protruding portion.

11. The back-contact battery according to claim 1, wherein, The thickness of the first sub-doping layer in the thickness direction is greater than that of the second sub-doping layer.

12. The back-contact battery according to claim 11, characterized in that, The thickness of the first sub-doping layer in the thickness direction is 50 nm - 300 nm; The thickness of the second sub-doping layer in the thickness direction is 30 nm - 200 nm.

13. The back-contact battery according to claim 1, characterized in that, The first doping layer further includes a first inner expansion layer formed in the convex portion, and the second doping layer further includes a second inner expansion layer formed in the first trench.

14. The back-contact battery according to claim 1, wherein, The first doping layer further includes a first blocking layer, and the first blocking layer is stacked between the first sub-doping layer and the second sub-doping layer.

15. The back contact battery according to claim 14, characterized in that, The back-contact battery includes a first dielectric layer located between the first doping layer and the silicon substrate, and the thickness of the first blocking layer in the thickness direction is less than that of the first dielectric layer.

16. The back-contact battery according to claim 1, characterized in that, The second doping layer includes a third sub-doping layer and a fourth sub-doping layer stacked, the third sub-doping layer is stacked on the first trench, and the fourth sub-doping layer is stacked on the side of the third sub-doping layer away from the silicon substrate.

17. The back contact battery according to claim 16, characterized in that, The second doping layer further includes a second blocking layer, and the second blocking layer is stacked between the third sub-doping layer and the fourth sub-doping layer.

18. A battery string, characterized in that, Comprising the back-contact battery according to any one of claims 1 - 17.

19. A battery component, characterized in that, Comprising the battery string according to claim 18.

20. A photovoltaic system, characterized in that, Comprising the battery module according to claim 19.

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