Back contact cell and method of making same, stacked cell, photovoltaic module

Abstract

The application relates to the photovoltaic field and provides a back contact cell, a preparation method of the back contact cell, a laminated cell and a photovoltaic module, and at least the reliability of the back contact cell can be improved. The back contact cell comprises a substrate, a first doped part, a second doped part, an insulating material layer, a first electrode and a second electrode. The substrate comprises a first surface and a second surface, the second surface is divided into a first area, a second area and a third area between the first area and the second area, the second area is recessed to the first surface relative to the first area, and the third area is inclined relative to the first area; the first doped part is located in the first area; the second doped part is at least partially located in the second area and the third area; the insulating material layer is at least partially located on the surface of the second doped part in the third area and faces away from the substrate; the first electrode is electrically connected with the first doped part, and the second electrode is electrically connected with the second doped part.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and in particular to a back contact battery and its preparation method, a tandem battery, and a photovoltaic module. Background Technology

[0002] As fossil fuels are gradually depleted, solar energy is becoming increasingly widely used as a new energy alternative. A solar cell is a device that converts sunlight into electrical energy. Solar cells utilize the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient use of electrical energy.

[0003] Back-contact solar cells are a type of solar cell where all the grid lines are located on the back of the cell. Because there are no metal grid lines obstructing the front of the cell, back-contact cells have increased light absorption efficiency, significantly improving short-circuit current and effectively increasing conversion efficiency, making them a promising technology. However, improving the reliability of back-contact solar cells is a pressing issue that needs to be addressed. Summary of the Invention

[0004] This application provides a back contact battery and its preparation method, a tandem battery, and a photovoltaic module, which can at least improve the reliability of the back contact battery.

[0005] This application provides a back contact battery. The back contact battery includes: a substrate, the substrate including a first surface and a second surface, the second surface being divided into a first region, a second region, and a third region located between the first region and the second region, the second region being recessed relative to the first region towards the first surface, and the third region being inclined relative to the first region; a first doped portion located in the first region; a second doped portion located at least partially in the second region and the third region; an insulating material layer, the second doped portion located at least partially in the third region being away from the surface of the substrate; a first electrode electrically connected to the first doped portion; and a second electrode electrically connected to the second doped portion.

[0006] Optionally, the second region includes: a first sub-region, wherein the second electrode is located at least on the side of the second doped portion of the first sub-region facing away from the substrate; and a second sub-region, wherein the second sub-region is located on at least one side of the first sub-region and is adjacent to the third region; wherein the insulating material layer is also located on the side of the first doped portion of the second sub-region facing away from the substrate.

[0007] Optionally, the surface of the second doped portion located in the third region facing away from the substrate has a first pyramid structure.

[0008] Optionally, the insulating material layer covers the first apex of the first pyramid structure; the distance between the surface of the insulating material layer on the first apex, facing away from the substrate, and the first apex is less than or equal to 20 μm.

[0009] Optionally, the insulating material layer is exposed at the first apex of the first pyramid structure; the height of the portion of the first pyramid structure not covered by the insulating material layer is a first height, and the ratio of the first height to the height of the first pyramid structure is less than or equal to 0.5.

[0010] Optionally, the first height is less than or equal to 4 μm; the height of the first pyramid structure is 2 μm to 8 μm.

[0011] Optionally, the surface of the second doped portion located in the second sub-region facing away from the substrate has a second pyramid structure.

[0012] Optionally, the insulating material layer covers the second apex of the second pyramid structure; the distance between the surface of the insulating material layer on the second apex that faces away from the substrate and the second apex is less than or equal to 1 μm.

[0013] Optionally, the insulating material layer is exposed at the second apex of the second pyramid structure; the height of the portion of the second pyramid structure not covered by the insulating material layer is the second height, and the ratio of the second height to the height of the second pyramid structure is less than or equal to one-third.

[0014] Optionally, the second height is less than or equal to 0.7 μm; the height of the second pyramid structure is 0.4 μm to 2.2 μm.

[0015] Optionally, the first region includes: a third sub-region, wherein the first electrode is located at least on the side of the first doped portion of the first sub-region facing away from the substrate; and a fourth sub-region, wherein the fourth sub-region is located on at least one side of the third sub-region and is adjacent to the third region; wherein the insulating material layer is also located on the side of the first doped portion of the fourth sub-region facing away from the substrate.

[0016] Optionally, the thickness of the insulating material layer on the side of the first doped portion located in the fourth sub-region away from the substrate is 0.1 μm to 20 μm.

[0017] Optionally, the insulating material layer is an insulating adhesive layer.

[0018] Optionally, the back contact battery further includes: a first conductive layer, the first conductive layer being located on the side of the first doped portion in the first region away from the substrate and electrically connected to the first electrode; a second conductive layer, the second conductive layer being located on the side of the second doped portion in the second region away from the substrate and electrically connected to the second electrode; wherein the insulating material layer is spaced apart from the first conductive layer; the insulating material layer is spaced apart from the second conductive layer.

[0019] This application also provides a method for fabricating a back contact battery. The method includes: obtaining a substrate, the substrate including a first surface and a second surface, the second surface being divided into a first region, a second region, and a third region located between the first region and the second region, the second region being recessed relative to the first region towards the first surface, the third region being inclined relative to the first region, a first doped portion being formed on the first region, and a second doped portion being formed on at least the second region and the third region; forming an insulating material layer, the insulating material layer being at least partially located on the surface of the second doped portion in the third region away from the substrate; and forming a first electrode and a second electrode, the first electrode being electrically connected to the first doped portion, and the second electrode being electrically connected to the second doped portion.

[0020] This application also provides a stacked battery. The stacked battery includes: a bottom battery, which is a back contact battery as described above, or a back contact battery prepared by a method described above for preparing a back contact battery; and a perovskite battery located on one side of the bottom battery.

[0021] This application also provides a photovoltaic module. The photovoltaic module includes: a battery string, which is formed by connecting a plurality of back-contact batteries as described above, or by connecting back-contact batteries prepared by the method described above, or by connecting a plurality of stacked batteries as described above; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film opposite to the surface of the battery string.

[0022] The technical solution provided in this application has at least the following advantages: In the back-contact battery provided in this application, the insulating material layer is at least partially located on the surface of the second doped portion in the third region that is away from the substrate. When printing the first electrode onto the side of the first doped portion away from the substrate, the insulating material layer can mitigate the leakage problem caused by the first electrode being offset to the second doped portion in the third region, thereby improving the reliability of the back-contact battery. The insulating material layer can also serve as a protective layer for the second doped portion in the third region, reducing the risk of metal ions from other parts (such as the first electrode) diffusing into the second doped portion in the third region and affecting the performance of the second doped portion, thus also improving the reliability of the back-contact battery. Attached Figure Description

[0023] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A partial top view of the first doped portion, the second doped portion, and the insulating material layer in a back contact battery provided in an embodiment of this application; Figure 2 A partial cross-sectional schematic diagram of a back contact battery provided in an embodiment of this application; Figure 3 A partial structural schematic diagram of a back contact battery provided in this application, showing the insulating material layer located on the side of the second doped portion of the third region away from the substrate in the third region; Figure 4 Another partial cross-sectional schematic diagram of the back contact battery provided in an embodiment of this application; Figure 5 A scanning electron microscope image of the insulating material layer in the back contact battery provided in this application embodiment; Figure 6 A schematic diagram of another partial structure of the insulating material layer in the back contact battery provided in this application, located on the side of the second doped portion in the third region away from the substrate; Figure 7 A partial structural diagram of an insulating material layer covering a second spire in a back contact battery provided in an embodiment of this application; Figure 8 A partial structural diagram of an insulating material layer exposed at the second spire in a back contact battery provided in an embodiment of this application; Figure 9 This is another partial cross-sectional schematic diagram of the back contact battery provided in an embodiment of this application; Figure 10 This is another partial cross-sectional schematic diagram of the back contact battery provided in an embodiment of this application; Figure 11 This is a schematic diagram of a stacked battery provided in an embodiment of this application; Figure 12 This is a schematic diagram of another structure of the stacked battery provided in an embodiment of this application; Figure 13This is a partial cross-sectional schematic diagram of a photovoltaic module provided in an embodiment of this application.

[0025] Explanation of reference numerals in the attached figures: 10. Substrate; 101. First surface; 102. Second surface; 103. First region; 1031. Third sub-region; 1032. Fourth sub-region; 104. Second region; 1041. First sub-region; 1042. Second sub-region; 105. Third region; 11. First doped portion; 12. Second doped portion; 13. Insulating material layer; 14. First electrode; 15. Second electrode; 16. First conductive layer; 17. Second conductive layer; 18. Tunneling layer; 19. Passivation layer; 20. Functional layer; 30. Bottom cell; 31. Perovskite cell; 311. First transport layer; 312. Perovskite functional layer; 313. Second transport layer; 314. Transparent conductive layer; 315. Anti-reflective layer; 40. Back contact cell; 41. Encapsulation layer; 42. Cover plate; 421. First cover plate; 422. Second cover plate; 43. Solder ribbon. Detailed Implementation

[0026] As can be seen from the background technology, the reliability of the back contact battery in the relevant technology needs to be improved.

[0027] Therefore, embodiments of this application provide a back-contact battery and its fabrication method, a tandem battery, and a photovoltaic module. In the back-contact battery, the insulating material layer can improve the leakage problem caused by the printing offset of the first electrode to the third region, thereby improving the reliability of the back-contact battery. The insulating material layer can also serve as a protective layer for the second doped portion of the third region, reducing the risk of metal ions from other parts (such as the first electrode) diffusing to the second doped portion of the third region and affecting the performance of the second doped portion, thus also improving the reliability of the back-contact battery.

[0028] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined. Similarly, "multiple sets" refers to two or more sets (including two sets), and "multiple pieces" refers to two or more pieces (including two pieces).

[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0031] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. For example, if the device or element in the illustration is inverted, then the element described as "below," "under," "below," or "bottom" of other elements or features will be oriented "above" or "top" of said other elements or features. Therefore, the term "below" may cover both above and below orientation depending on the context in which the term is used, which will be obvious to those skilled in the art. Materials may be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0032] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0033] In the description of the embodiments of this application, "electrically connected to one component" means that both components are made of conductive materials, and the two components are in direct contact and connected or connected via other conductive materials. When the photovoltaic module is generating electricity, current flows between the two components. "Electrically contacting one component to another" means that the two components are not only in contact, but also, because both components are made of conductive materials, current flows between the two components when the photovoltaic module is generating electricity.

[0034] In the description of embodiments of this application, the terms "about," "approximately," "roughly," or "about" for a numerical value referring to a specific parameter include the numerical value, and those skilled in the art will understand that the deviation from the numerical value is within the acceptable tolerance of the specific parameter. For example, "about" or "about" for a numerical value may include additional numerical values ​​that are in the range of 90.0% to 110.0% of the numerical value, such as in the range of 95.0% to 105.0%, 97.5% to 102.5%, 99.0% to 101.0%, 99.5% to 100.5%, or 99.9% to 100.1%.

[0035] In the accompanying drawings corresponding to the embodiments of this application, the thickness and / or area of ​​layers, films, panels, regions, etc., are enlarged for better understanding and ease of description. Throughout the specification, the same reference numerals denote the same elements. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0036] In the description of embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be an intermediate component between the two components. Conversely, when describing a component on the surface of another component, or a component "directly" on another component, or a component surface on which another component is formed or disposed, it indicates that there is no intermediate component between the two components. For simplicity and clarity, various components may be drawn at any scale. In the drawings, some components may be omitted for simplicity.

[0037] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "the component" is also intended to include the plural form unless the context clearly indicates otherwise.

[0038] The “components” mentioned above can refer to layers, membranes, regions, parts, plates, or structures, etc.

[0039] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0040] Figure 1 This is a partial top view of the first doped portion, the second doped portion, and the insulating material layer in a back contact battery provided in an embodiment of this application. Figure 2 This is a partial cross-sectional schematic diagram of a back contact battery provided in an embodiment of this application. Figure 1 It is mainly used to illustrate the positional relationship of multiple first zones, multiple second zones, and multiple third zones, but does not illustrate the first electrode and the second electrode. Figure 2 For along Figure 1 A schematic diagram of a cross-sectional structure along the A1A2 direction.

[0041] refer to Figure 2 The back contact battery includes: a substrate 10, a first doped portion 11, a second doped portion 12, an insulating material layer 13, a first electrode 14, and a second electrode 15. The substrate 10 includes a first surface 101 and a second surface 102. The second surface 102 is divided into a first region 103, a second region 104, and a third region 105 located between the first region 103 and the second region 104. The second region 104 is recessed relative to the first region 103 towards the first surface 101, and the third region 105 is inclined relative to the first region 103. The first doped portion 11 is located in the first region 103. The second doped portion 12 is at least partially located in the second region 104 and the third region 105. The second doped portion 12 of the insulating material layer 13, at least partially located in the third region 105, is away from the surface of the substrate 10. The first electrode 14 is electrically connected to the first doped portion 11, and the second electrode 15 is electrically connected to the second doped portion 12.

[0042] The substrate 10 is used to receive light and generate photogenerated carriers. In some embodiments, the substrate 10 may be a semiconductor substrate 10.

[0043] In some embodiments, the material of the substrate 10 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material may be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon.

[0044] In some embodiments, the substrate 10 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium arsenide, perovskite, cadmium telluride, copper indium selenide, etc.

[0045] The substrate 10 can also be a sapphire substrate, a silicon substrate on an insulator, or a germanium substrate on an insulator.

[0046] The substrate 10 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type dopant element, which can be at least one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate 10 is doped with a P-type dopant element, which can be at least one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0047] The substrate 10 includes a first surface 101 and a second surface 102 facing each other. In some embodiments, the back-contact cell used in a single-glass photovoltaic module is considered a single-sided cell, in which case the first surface 101 can serve as a light-receiving surface for receiving sunlight, and the second surface 102 serves as a back-lighting surface. In some embodiments, the back-contact cell used in a double-glass module or a bifacial module is considered a bifacial cell, in which case both the first surface 101 and the second surface 102 can serve as light-receiving surfaces and can both be used to receive sunlight. It is understood that the back-lighting surface referred to in the embodiments of this application can also receive sunlight, but the degree of sunlight reception is weaker than that of the light-receiving surface, and therefore it is defined as a back-lighting surface.

[0048] In some embodiments, a flocking process may be performed on at least one of the first surface 101 and the second surface 102 to form a flocked surface on at least one of the first surface 101 and the second surface 102, thereby enhancing the absorption and utilization rate of the first surface 101 and / or the second surface 102 for incident light.

[0049] In some embodiments, the second surface 102 is divided into a first region 103, a second region 104, and a third region 105 located between the first region 103 and the second region 104.

[0050] The first region 103, the second region 104, and the third region 105 are artificially divided regions. The second region 104 is recessed relative to the first region 103 towards the first surface 101, and the third region 105 is inclined relative to the first region 103. The inclined third region 105 serves as a transition region between the first region 103 and the second region 104, avoiding abrupt changes in height between the first region 103 and the second region 104. When forming the second doped portion 12, the inclined third region 105 allows the second doped portion 12 to cover the third region 105 relatively uniformly, thereby improving the passivation effect of the second doped portion 12 on the substrate 10.

[0051] In some embodiments, the second surface 102 may be divided into a plurality of first regions 103 arranged along the first direction X, a plurality of second regions 104 arranged along the first direction X, and a plurality of third regions 105 arranged along the first direction X. The first regions 103 and the second regions 104 are alternately distributed, and the third regions 105 are located between the first regions 103 and the second regions 104.

[0052] In some embodiments, the first region 103 is a polished surface. That is, the first region 103 is a surface that has undergone polishing treatment.

[0053] Figure 3 This is a partial structural diagram of a back contact battery provided in this application, showing the insulating material layer located in the third region on the side opposite to the substrate in the second doped portion.

[0054] refer to Figure 3 In some embodiments, the tilt angle α of the third region 105 relative to the first region 103 can be 140° to 170°. For example, the tilt angle α of the third region 105 relative to the first region 103 can be 140° to 150°, 150° to 160°, or 160° to 170°. Optionally, the tilt angle α of the third region 105 relative to the first region 103 can be 140°, 145°, 150°, 155°, 160°, 165°, or 170°.

[0055] In some embodiments, the length of the third region 105 along the first direction X can be 3.5 μm to 25 μm. For example, the length of the third region 105 along the first direction X can be 3.5 μm to 10 μm, 10 μm to 15 μm, 15 μm to 20 μm, or 20 μm to 25 μm. Optionally, the length of the third region 105 along the first direction X can be 3.5 μm, 5 μm, 6.75 μm, 10 μm, 12.5 μm, 15 μm, 17.5 μm, 20 μm, 22.5 μm, or 25 μm.

[0056] The doping element in the first doped portion 11 and the doping element in the second doped portion 12 have different conductivity types. For example, the doping element in the first doped portion 11 is either a P-type doping element or an N-type doping element, and the doping element in the second doped portion 12 is either a P-type doping element or an N-type doping element. For a detailed explanation of the P-type and N-type doping elements, please refer to the description corresponding to the aforementioned substrate 10; further details will not be repeated here.

[0057] The second doped portion 12 is located at least in the second region 104 and the third region 105. In some cases, the second doped portion 12 is located only in the second region 104 and the third region 105. In other cases, the second doped portion 12 is located not only in the second region 104 and the third region 105, but also in a portion of the first region 103, wherein the second doped portion 12 in the first region 103 is located on the side of the first doped portion 11 in the first region 103 that is away from the substrate 10.

[0058] In some embodiments, the material of the first doped portion 11 may include doped polycrystalline silicon, doped amorphous silicon, doped microcrystalline silicon, or doped nanocrystalline silicon. For example, the first doped portion 11 may be doped polycrystalline silicon with an N-type dopant element.

[0059] In some embodiments, the material of the second doped portion 12 may include doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. For example, the second doped portion 12 may be doped amorphous silicon with p-type dopant elements.

[0060] The insulating material layer 13 is at least partially located on the surface of the second doped portion 12 of the third region 105 that faces away from the substrate 10. The insulating material layer 13 can improve the leakage problem caused by the printing offset of the first electrode 14 to the third region 105, thereby improving the reliability of the back contact battery. The insulating material layer 13 can also serve as a protective layer for the second doped portion 12 of the third region 105, reducing the risk of metal ions from other parts (such as the first electrode 14) diffusing to the second doped portion 12 of the third region 105 and affecting the passivation effect of the second doped portion 12, thereby also improving the reliability of the back contact battery.

[0061] In some embodiments, the insulating material layer 13 may be an insulating adhesive layer. Insulating adhesive layers are less expensive and have better stability, which helps to reduce the manufacturing cost of the back contact battery and improve its reliability.

[0062] In some embodiments, the insulating layer 13 may be made of a resin material, which may include, but is not limited to, epoxy resin, acrylic resin, or silicone resin. This helps to reduce the manufacturing cost of the back contact battery.

[0063] The first electrode 14 is located on the side of the first doped portion 11 away from the substrate 10 and is electrically connected to the first doped portion 11 for collecting charge carriers. The second electrode 15 is located on the side of the second doped portion 12 away from the substrate 10 and is electrically connected to the second doped portion 12 for collecting charge carriers.

[0064] The metallic material of the first electrode 14 includes at least one of gold, silver, copper, nickel, aluminum, and tin. The metallic material of the second electrode 15 includes at least one of gold, silver, copper, nickel, aluminum, and tin.

[0065] Figure 4 This is another partial cross-sectional schematic diagram of the back contact battery provided in an embodiment of this application.

[0066] refer to Figure 4 In some embodiments, the second region 104 includes: a first sub-region 1041 and a second sub-region 1042, with the second electrode 15 located at least on the side of the second doped portion 12 of the first sub-region 1041 facing away from the substrate 10; the second sub-region 1042 is located on at least one side of the first sub-region 1041 and adjacent to the third region 105; wherein, the insulating material layer 13 is also located on the side of the first doped portion 11 of the second sub-region 1042 facing away from the substrate 10. Thus, the insulating material layer 13 can improve the leakage problem caused by the printing offset of the first electrode 14 to the second doped portion 12 of the second sub-region 1042, thereby improving the reliability of the back contact battery. The insulating material layer 13 can also serve as a protective layer for the second doped portion 12 of the second sub-region 1042, reducing the risk of metal ions from other parts (such as the first electrode 14) diffusing to the second doped portion 12 of the second sub-region 1042 and affecting the passivation effect of the second doped portion 12, thereby also improving the reliability of the back contact battery.

[0067] It should be noted that the first sub-region 1041 and the second sub-region 1042 are artificially divided regions, and there is no substantial boundary between the first sub-region 1041 and the second sub-region 1042. The projection of the second electrode 15 along the second direction Y is at least located in the first sub-region 1041, and the projection of the insulating material layer 13 along the second direction Y is located in the second sub-region 1042. The second direction Y is defined as the thickness direction of the substrate 10.

[0068] In some cases, the second electrode 15 is located on the side of the second doped portion 12 of the first sub-region 1041 that is away from the substrate 10, that is, the projection of the second electrode 15 along the second direction Y is located in the first sub-region 1041. In other cases, the second electrode 15 is located not only on the side of the second doped portion 12 of the first sub-region 1041 that is away from the substrate 10, but also on the side of the second doped portion 12 of the second sub-region 1042 that is away from the substrate 10, that is, the projection of the second electrode 15 along the second direction Y is located in both the first sub-region 1041 and the second sub-region 1042.

[0069] In some embodiments, the length of the second sub-region 1042 along the first direction X is less than or equal to 100 μm. Exemplarily, the length of the second sub-region 1042 along the first direction X is 0.1 μm to 10 μm, 10 μm to 30 μm, 30 μm to 50 μm, 50 μm to 80 μm, or 80 μm to 100 μm. Optionally, the length of the second sub-region 1042 along the first direction X is 0.1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 65 μm, 70 μm, 80 μm, 90 μm, or 100 μm.

[0070] Figure 5 A scanning electron microscope image of the insulating material layer in the back contact battery provided in an embodiment of this application.

[0071] Figure 5 This illustration primarily depicts the situation where the insulating material layer 13 is located in the second sub-region 1042 and the third region 105. Specifically, because the thickness of the second doped portion 12 is relatively small, it is... Figure 5 The second doped part 12 cannot be directly observed.

[0072] Continue to refer to Figure 2 In some embodiments, the second doped portion 12 located in the third region 105 has a first pyramid structure (not identified) on the surface opposite to the substrate 10.

[0073] In some embodiments, the third region 105 has a first textured structure (not identified) similar to the first pyramidal structure. The second doped portion 12 located in the third region 105 can be considered as conformally covering the first textured structure, such that the surface of the second doped portion 12 in the third region 105 facing away from the substrate 10 has the first pyramidal structure. That is, the morphology of the first pyramidal structure can be approximately the same as the morphology of the first textured structure. The first textured structure in the third region 105 can improve the adhesion of the second doped portion 12, thereby improving the uniformity of the formed second doped portion 12 and enhancing the performance of the back contact battery.

[0074] The first pyramid structure has a first spire.

[0075] It should be noted that, Figures 2 to 4 The illustration shows a first pyramid structure with one first apex; in reality, a first pyramid structure can have multiple first apexes. This application does not limit the number of apexes in the first pyramid structure.

[0076] Continue to refer to Figure 3In some embodiments, the insulating material layer 13 covers the first apex of the first pyramid structure; the distance D1 between the surface of the insulating material layer 13 on the first apex facing away from the substrate 10 and the first apex can be less than or equal to 20 μm. Exemplarily, the distance D1 between the surface of the insulating material layer 13 on the first apex facing away from the substrate 10 and the first apex can be 0.1 μm to 1 μm, 1 μm to 5 μm, 5 μm to 10 μm, 10 μm to 15 μm, or 15 μm to 20 μm. Optionally, the distance D1 between the surface of the insulating material layer 13 on the first apex facing away from the substrate 10 and the first apex can be 0.1 μm, 0.55 μm, 1 μm, 2.5 μm, 5 μm, 7.5 μm, 10 μm, 12.5 μm, 15 μm, 17.5 μm, or 20 μm. When the distance D1 between the insulating material layer 13 located on the first tower tip and the surface of the substrate 10 is within the range described above, the leakage problem caused by the first electrode 14 being printed off to the second doped portion 12 of the third region 105 can be effectively improved, and the waste of resources can also be avoided.

[0077] Figure 6 This is a schematic diagram of another partial structure of the back contact battery provided in this application, showing that the insulating material layer is located in the third region on the side opposite to the substrate in the second doped portion. Figure 3 and Figure 6 The difference is: Figure 3 The insulating material layer 13 covers the first spire. Figure 6 The insulating material layer 13 is exposed at the first spire.

[0078] refer to Figure 6 In some embodiments, the insulating material layer 13 exposes the first apex of the first pyramid structure; the height of the portion of the first pyramid structure not covered by the insulating material layer 13 is a first height H1, and the ratio of the first height to the height H2 of the first pyramid structure is less than or equal to 0.5. For example, the ratio of the first height H1 to the height H2 of the first pyramid structure ranges from 0.01 to 0.15, 0.15 to 0.3, or 0.3 to 0.5. Optionally, the ratio of the first height H1 to the height H2 of the first pyramid structure ranges from 0.01, 0.05, 0.08, 0.1, 0.15, 0.2, 0.225, 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5. The ratio of the first height H1 to the height H2 of the first pyramid structure is within the above range, which makes the first height H1 smaller. That is, the height of the part of the first pyramid structure not covered by the insulating material layer 13 is smaller, which is beneficial for the insulating material layer 13 to improve the leakage problem caused by the printing offset of the first electrode 14 to the second doped part 12 of the third region 105.

[0079] The first height H1 is the height of the portion of the first pyramid structure not covered by the insulating material layer 13, that is, the distance along the second direction Y between the first pyramid tip and the insulating material layer 13 adjacent to the first pyramid tip. The height H2 of the first pyramid is the distance along the second direction Y between the first pyramid tip and the lowest point closest to the base 10.

[0080] In some embodiments, the insulating material layer 13 has a certain degree of fluidity, so that when it is placed on the first pyramid structure, the insulating material layer 13 can cover a portion of the first pyramid structure and expose the first apex of the first pyramid structure. In other embodiments, the insulating material layer 13 has very low fluidity, and the insulating material layer 13 can also conformally cover the first pyramid structure.

[0081] In some embodiments, the third region 105 has a plurality of first pyramid structures. In some cases, the insulating material layer 13 may simultaneously cover the first apex of the plurality of first pyramid structures. In other cases, the insulating material layer 13 may simultaneously expose the first apex of the plurality of first pyramid structures. In still other cases, the insulating material layer 13 may cover only a portion of the first apex of the first pyramid structure, exposing only a portion of the first apex of the first pyramid structure.

[0082] In some embodiments, the first height H1 is less than or equal to 4 μm. For example, the first height H1 can be 0.1 μm to 1 μm, 1 μm to 2 μm, 2 μm to 3 μm, or 3 μm to 4 μm. Optionally, the first height H1 can be 0.1 μm, 0.55 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, or 4 μm.

[0083] It should be noted that the first height H1 refers to the average height of the portion of the first pyramid structure in each region of the surface of the second doped portion 12 of the third region 105 that is not covered by the insulating material layer 13. In some cases, the height of the portion of the first pyramid structure in each region of the surface of the second doped portion 12 of the third region 105 that is not covered by the insulating material layer 13 is within the range of the first height H1; in other cases, the height of the portion of the first pyramid structure in most regions of the surface of the second doped portion 12 of the third region 105 that is not covered by the insulating material layer 13 is within the range of the first height H1, while the height of the portion of the first pyramid structure in a small portion of the third region 105 that is not covered by the insulating material layer 13 is not within the range of the first height H1, but the overall average height of the portion of the first pyramid structure in the surface of the second doped portion 12 of the third region 105 that is not covered by the insulating material layer 13 is the first height H1.

[0084] It should also be noted that when actually measuring the first height H1, several sampling areas can be selected at different positions on the surface of the second doped portion 12 of the third region 105 facing away from the substrate 10. The average height of the portion of the first pyramid structure not covered by the insulating material layer 13 in these sampling areas can be calculated as the first height H1. It is understandable that after measuring the height of the portion of the first pyramid structure not covered by the insulating material layer 13 in these sampling areas, the maximum and minimum height values ​​can be discarded, and the average of the remaining height values ​​can be calculated as the first height H1. This eliminates measurements that are not representative.

[0085] The height H2 of the first pyramid structure can be 2μm to 8μm. For example, the height H2 of the first pyramid structure can be 2μm to 4μm, 4μm to 6μm, or 6μm to 8μm. Optionally, the height H2 of the first pyramid structure can be 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, or 8μm.

[0086] It should be noted that the height H2 of the first pyramid structure (hereinafter referred to as the first preset height) refers to the average height H2 of the first pyramid structure in each region of the surface of the second doped portion 12 of the third region 105 facing away from the substrate 10. In some cases, the height H2 of the first pyramid structure in each region of the surface of the second doped portion 12 of the third region 105 facing away from the substrate 10 is within the first preset height; in other cases, the height H2 of the first pyramid structure in most regions of the surface of the second doped portion 12 of the third region 105 facing away from the substrate 10 is within the first preset height, while the height H2 of a small portion of the first pyramid structure is not within the first preset height, but the overall average height of the first pyramid structure in the surface of the second doped portion 12 of the third region 105 facing away from the substrate 10 is the first preset height.

[0087] It should also be noted that when actually measuring the height H2 of the first pyramid structure, several sampling areas can be selected at different positions on the surface of the second doped portion 12 of the third region 105 facing away from the substrate 10. The average height H2 of the first pyramid structure measured in these sampling areas is calculated as the height H2 of the first pyramid structure. It is understandable that after measuring the height of the first pyramid structure in these sampling areas, the maximum and minimum values ​​can be discarded, and the average of the remaining height measurements can be calculated as the height H2 of the first pyramid structure. This eliminates measurements that are not representative.

[0088] Continue to refer to Figure 4In some embodiments, the second doped portion 12 located in the second sub-region 1042 has a second pyramid structure on the surface facing away from the substrate 10. The second sub-region 1042 has a second textured structure similar to the second pyramid structure, and the second doped portion 12 located in the second sub-region 1042 can be considered as conformally covering the second textured structure, such that the surface of the second doped portion 12 of the second sub-region 1042 facing away from the substrate 10 has a second pyramid structure. That is, the morphology of the second pyramid structure can be approximately the same as the morphology of the second textured structure. The second textured structure in the second sub-region 1042 can increase the absorption and utilization rate of the second surface 102 for incident light.

[0089] In some embodiments, the second doped portion 12 of the first sub-region 1041 has a second pyramid structure on the surface facing away from the substrate 10, and the first sub-region 1041 has a second textured structure. This can increase the absorption and utilization rate of the second surface 102 for incident light.

[0090] It should be noted that, Figure 2 and Figure 4 The illustration depicts a second pyramid structure with one second apex; in reality, a second pyramid structure can have multiple second apexes. This application does not limit the number of apexes in the first pyramid structure.

[0091] Figure 7 This is a partial structural diagram of an insulating material layer covering a second spire in a back contact battery provided in an embodiment of this application.

[0092] refer to Figure 7 In some embodiments, the insulating material layer 13 covers the second apex of the second pyramid structure; the distance between the surface of the insulating material layer 13 on the second apex facing away from the substrate 10 and the second apex is less than or equal to 1 μm. Exemplarily, the distance between the surface of the insulating material layer 13 on the second apex facing away from the substrate 10 and the second apex is 0.01 μm to 0.2 μm, 0.2 μm to 0.4 μm, 0.4 μm to 0.6 μm, 0.6 μm to 0.8 μm, or 0.8 μm to 1 μm. Optionally, the distance between the surface of the insulating material layer 13 on the second apex facing away from the substrate 10 and the second apex is 0.01 μm, 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, or 1 μm. The distance between the surface of the insulating material layer 13 on the second tower and the substrate 10 is within the range mentioned above. This can effectively improve the leakage problem caused by the first electrode 14 being printed off to the second doped portion 12 of the second sub-region 1042, while also helping to save on the manufacturing cost of the back contact battery.

[0093] Figure 8This is a partial structural diagram of an insulating material layer exposed at the second spire in a back contact battery provided in an embodiment of this application.

[0094] refer to Figure 8 In some embodiments, the insulating material layer 13 exposes the second apex of the second pyramid structure; the height of the portion of the second pyramid structure not covered by the insulating material layer 13 is a second height H3, and the ratio of the second height H3 to the height H4 of the second pyramid structure is less than or equal to one-third. For example, the ratio of the second height H3 to the height H4 of the second pyramid structure can be 0.01~0.1, 0.1~0.2, or 0.2~0.33. Optionally, the ratio of the second height H3 to the height H4 of the second pyramid structure can be 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, or 0.33.

[0095] In some embodiments, the second height H3 may be less than or equal to 0.7 μm. For example, the second height H3 may be 0.1 μm to 0.3 μm, 0.3 μm to 0.5 μm, or 0.5 μm to 0.7 μm. Optionally, the second height H3 may be 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, or 0.7 μm.

[0096] It should be noted that the second height H3 refers to the average height of the portion of the second pyramid structure in each region of the second doped portion 12 on the surface of the second sub-region 1042 away from the substrate 10 that is not covered by the insulating material layer 13. In some cases, the height of the portion of the second pyramid structure in each region of the second doped portion 12 on the surface of the second sub-region 1042 away from the substrate 10 that is not covered by the insulating material layer 13 is within the range of the second height H3; in other cases, the height of the portion of the second pyramid structure in most regions of the second doped portion 12 on the surface of the second sub-region 1042 away from the substrate 10 that is not covered by the insulating material layer 13 is within the range of the second height H3, while the height of the portion of the second pyramid structure in a small portion of the second sub-region 1042 away from the substrate 10 that is not covered by the insulating material layer 13 is not within the range of the second height H3, but the overall average height of the portion of the second pyramid structure in the second doped portion 12 on the surface of the second sub-region 1042 away from the substrate 10 that is not covered by the insulating material layer 13 is the second height H3.

[0097] It should also be noted that when actually measuring the second height H3, several sampling areas can be selected at different positions on the surface of the second doped portion 12 of the second sub-region 1042 facing away from the substrate 10. The average height of the portion of the second pyramid structure not covered by the insulating material layer 13 in these sampling areas is calculated as the second height H3. It is understandable that after measuring the height of the portion of the second pyramid structure not covered by the insulating material layer 13 in these sampling areas, the maximum and minimum height values ​​can be discarded, and the average of the remaining height values ​​can be calculated as the second height H3. This eliminates measurements that are not representative.

[0098] In some embodiments, the height H4 of the second pyramid structure can be 0.4 μm to 2.2 μm. For example, the height H4 of the second pyramid structure can be 0.4 μm to 0.8 μm, 0.8 μm to 1.4 μm, 1.4 μm to 1.8 μm, or 1.8 μm to 2.2 μm. Optionally, the height H4 of the second pyramid structure can be 0.4 μm, 0.6 μm, 0.8 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, or 2.2 μm.

[0099] It should be noted that the height H4 of the second pyramid structure (hereinafter referred to as the second preset height) refers to the average height H4 of the second pyramid structure in each region on the surface of the second doped portion 12 of the second sub-region 1042 facing away from the substrate 10. In some cases, the height H4 of the second pyramid structure in each region on the surface of the second doped portion 12 of the second sub-region 1042 facing away from the substrate 10 is within the range of the second preset height; in other cases, the height H4 of the second pyramid structure in most regions on the surface of the second doped portion 12 of the second sub-region 1042 facing away from the substrate 10 is within the range of the second preset height, while the height H4 of a small portion of the second pyramid structure is not within the range of the second preset height, but the overall average height of the second pyramid structure on the surface of the second doped portion 12 of the second sub-region 1042 facing away from the substrate 10 is the second preset height.

[0100] It should also be noted that when actually measuring the height H4 of the second pyramid structure, several sampling areas can be selected at different positions on the surface of the second doped portion 12 of the second sub-region 1042 facing away from the substrate 10. The average height H4 of the second pyramid structure measured in these sampling areas is calculated as the height H4 of the second pyramid structure. It is understandable that after measuring the height H4 of the second pyramid structure in these sampling areas, the maximum and minimum values ​​can be discarded, and the average of the remaining height measurements can be calculated as the height H4 of the second pyramid structure. This eliminates measurements that are not representative.

[0101] Figure 9 This is another partial cross-sectional schematic diagram of the back contact battery provided in an embodiment of this application.

[0102] refer to Figure 9 In some embodiments, the first region 103 includes a third sub-region 1031 and a fourth sub-region 1032. The first electrode 14 is located at least on the side of the first doped portion 11 of the first sub-region 1031 facing away from the substrate 10. The fourth sub-region 1032 is located on at least one side of the third sub-region 1031 and is adjacent to the third region 105. An insulating material layer 13 is also located on the side of the first doped portion 11 of the fourth sub-region 1032 facing away from the substrate 10. Thus, the insulating material layer 13 can improve the leakage problem caused by the second electrode 15 being printed off-center to the first doped portion 11 of the fourth sub-region 1032, thereby improving the reliability of the back contact battery. The insulating material layer 13 can also serve as a protective layer for the first doped portion 11 of the fourth sub-region 1032, reducing the risk of metal ions from other parts (such as the second electrode 15) diffusing to the first doped portion 11 of the fourth sub-region 1032 and affecting the passivation effect of the second doped portion 12, thereby also improving the reliability of the back contact battery.

[0103] It should be noted that the third sub-region 1031 and the fourth sub-region 1032 are artificially divided regions, and there is no substantial boundary between the third sub-region 1031 and the fourth sub-region 1032. The projection of the first electrode 14 along the second direction Y is located at least in the third sub-region 1031, and the projection of the insulating material layer 13 along the second direction Y is located in the fourth sub-region 1032.

[0104] In some cases, the first electrode 14 is located on the side of the second doped portion 12 of the third sub-region 1031 that is away from the substrate 10, that is, the projection of the first electrode 14 along the second direction Y is located in the third sub-region 1031. In other cases, the first electrode 14 is located not only on the side of the second doped portion 12 of the third sub-region 1031 that is away from the substrate 10, but also on the side of the second doped portion 12 of the fourth sub-region 1032 that is away from the substrate 10, that is, the projection of the first electrode 14 along the second direction Y is located in both the third sub-region 1031 and the fourth sub-region 1032.

[0105] In some embodiments, the length of the fourth sub-region 1032 along the first direction X is less than or equal to 100 μm. Exemplarily, the length of the fourth sub-region 1032 along the first direction X is 0.1 μm to 10 μm, 10 μm to 30 μm, 30 μm to 50 μm, 50 μm to 80 μm, or 80 μm to 100 μm. Optionally, the length of the fourth sub-region 1032 along the first direction X is 0.1 μm, 5 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 65 μm, 70 μm, 80 μm, 90 μm, or 100 μm.

[0106] In some embodiments, the thickness of the insulating material layer 13 on the side of the first doped portion 11 in the fourth sub-region 1032 facing away from the substrate 10 can be 0.1 μm to 20 μm. For example, the thickness of the insulating material layer 13 on the side of the first doped portion 11 in the fourth sub-region 1032 facing away from the substrate 10 can be 0.1 μm to 1 μm, 1 μm to 5 μm, 5 μm to 10 μm, 10 μm to 15 μm, or 15 μm to 20 μm. Optionally, the thickness of the insulating material layer 13 on the side of the first doped portion 11 in the fourth sub-region 1032 facing away from the substrate 10 can be 0.1 μm, 0.55 μm, 1 μm, 2.5 μm, 5 μm, 7.5 μm, 10 μm, 12.5 μm, 15 μm, 17.5 μm, or 20 μm. Thus, the insulating material layer 13 can effectively improve the leakage problem caused by the second electrode 15 being printed off to the first doped part 11 of the fourth sub-region 1032, and can also save the manufacturing cost of the back contact battery.

[0107] In some embodiments, the back contact battery may further include: a first conductive layer 16, which is located on the side of the first doped portion 11 of the first region 103 opposite to the substrate 10 and is electrically connected to the first electrode 14. An insulating material layer 13 may be spaced apart from the first conductive layer 16. In this way, the amount of material used in the insulating material layer 13 can be saved, thereby reducing the manufacturing cost of the back contact battery.

[0108] The first conductive layer 16 can reduce the contact resistance between the first electrode 14 and the first doped portion 11, thereby improving the efficiency of the first electrode 14 in collecting charge carriers. The material of the first conductive layer 16 may include at least one of fluorine-doped tin oxide, aluminum-doped zinc oxide, tin-doped indium oxide, tungsten-doped indium oxide, molybdenum-doped indium oxide, cerium-doped indium oxide, and indium hydroxide.

[0109] In other embodiments, the insulating material layer 13 may be stacked with the first conductive layer 16 along the second direction Y, that is, the insulating material layer 13 may not be spaced apart from the first conductive layer 16.

[0110] In some embodiments, the back contact battery may further include a second conductive layer 17, which is located on the side of the second doped portion 12 of the second region 104 opposite to the substrate 10 and is electrically connected to the second electrode 15; wherein, an insulating material layer 13 is spaced apart from the second conductive layer 17. In this way, the amount of material used in the insulating material layer 13 can be saved, thereby reducing the manufacturing cost of the back contact battery.

[0111] The second conductive layer 17 can reduce the contact resistance between the second electrode 15 and the second doped portion 12, thereby improving the efficiency of the second electrode 15 in collecting charge carriers. The material of the second conductive layer 17 may include at least one of fluorine-doped tin oxide, aluminum-doped zinc oxide, tin-doped indium oxide, tungsten-doped indium oxide, molybdenum-doped indium oxide, cerium-doped indium oxide, and indium hydroxide.

[0112] In other embodiments, the insulating material layer 13 may be stacked with the second conductive layer 17 along the second direction Y, that is, the insulating material layer 13 may not be spaced apart from the second conductive layer 17.

[0113] In some embodiments, the back contact cell further includes a tunneling layer 18 located between the first doped portion 11 and the substrate 10. The tunneling layer 18 is used to saturate the dangling bonds of the second surface 102, reduce the defect state density of the second surface 102, reduce the recombination centers of the second surface 102 to reduce the carrier recombination rate, and also to form band bends to achieve selective carrier transport, thereby improving the efficiency of the first electrode 14 in collecting carriers.

[0114] The material of the tunneling layer 18 may include, but is not limited to, silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

[0115] In some embodiments, the back contact cell further includes a passivation layer 19, which is located between the second doped portion 12 and the substrate 10. The passivation layer 19 is used to saturate the dangling bonds of the second surface 102, reduce the defect state density of the second surface 102, and reduce the recombination centers of the second surface 102 to reduce the carrier recombination rate.

[0116] The material of the passivation layer 19 may include, but is not limited to, amorphous silicon (such as intrinsic amorphous silicon or micro-doped amorphous silicon), silicon oxide, silicon nitride, silicon oxynitride, or silicon carbide.

[0117] It is understandable that when the third region 105 has a first textured structure, the passivation layer 19 and the second doped portion 12 located in the third region 105 conformally cover the first textured structure, so that the surface of the second doped portion 12 of the third region 105 facing away from the substrate 10 can have a first pyramid structure. When the second sub-region 1042 has a textured structure, the passivation layer 19 and the second doped portion 12 located in the second sub-region 1042 conformally cover the first textured structure, so that the surface of the second doped portion 12 of the second sub-region 1042 facing away from the substrate 10 can have a first pyramid structure.

[0118] Figure 10 This is another partial cross-sectional schematic diagram of the back contact battery provided in the embodiments of this application.

[0119] refer to Figure 10In some embodiments, the back contact battery may further include a functional layer 20 located on the first surface 101. In some cases, the functional layer 20 can be used to passivate the substrate 10, reduce the defect state density of the substrate 10, and better suppress carrier recombination of the substrate 10. In other cases, the functional layer 20 can provide a good anti-reflection effect, reduce the reflection of incident light by the substrate 10, and improve the utilization rate of incident light by the substrate 10. In still other cases, the functional layer 20 can not only passivate the substrate 10, but also provide a good anti-reflection effect. That is, the functional layer 20 can serve a passivation function and / or an optical modulation function.

[0120] The functional layer 20 can be a single-layer structure or a multi-layer structure. In a multi-layer structure, the materials of different layers can be different from each other, or some layers can be made of the same material but different from the materials of other layers. For example, the functional layer 20 can be a multi-layer structure of silicon nitride and aluminum oxide layers.

[0121] In some embodiments, the material of the functional layer 20 may include, but is not limited to, silicon oxide, aluminum oxide, silicon nitride, and silicon oxynitride.

[0122] Accordingly, another aspect of this application provides a method for preparing a back contact battery. This method can prepare the back contact battery in any of the above embodiments. It should be noted that the parts that are the same as or corresponding to the foregoing embodiments can be referred to the corresponding descriptions of the foregoing embodiments, and will not be repeated below.

[0123] Continue to refer to Figure 2 The method for fabricating a back contact battery includes: obtaining a substrate 10, the substrate 10 including a first surface 101 and a second surface 102, the second surface 102 being divided into a first region 103, a second region 104 and a third region 105 located between the first region 103 and the second region 104, the second region 104 being recessed relative to the first region 103 towards the first surface 101, the third region 105 being inclined relative to the first region 103, a first doped portion 11 being formed on the first region 103, and a second doped portion 12 being formed on at least the second region 104 and the third region 105; forming an insulating material layer 13, the insulating material layer 13 being at least partially located on the surface of the second doped portion 12 in the third region 105 away from the surface of the substrate 10; forming a first electrode 14 and a second electrode 15, the first electrode 14 being electrically connected to the first doped portion 11, and the second electrode 15 being electrically connected to the second doped portion 12.

[0124] In some embodiments, an insulating material layer 13 is formed first, followed by the formation of the first electrode 14 and the second electrode 15. By forming the insulating material layer 13 first, leakage problems caused by the printing of the first electrode 14 to the second doped portion 12 in the third region 105 can be mitigated when printing the first electrode 14 onto the side of the first doped portion 11 away from the substrate 10, thereby improving the reliability of the back contact battery.

[0125] In the back contact battery fabrication method provided in this application, an insulating material layer 13 is formed on the surface of the second doped portion 12 located in the third region 105 away from the substrate 10. When the first electrode 14 is printed onto the surface of the first doped portion 11 away from the substrate 10, the insulating material layer 13 can improve the leakage problem caused by the printing of the first electrode 14 offset to the second doped portion 12 in the third region 105, thereby improving the reliability of the back contact battery. The insulating material layer 13 can also serve as a protective layer for the second doped portion 12 in the third region 105, reducing the risk of metal ions from other parts (such as the first electrode 14) diffusing to the second doped portion 12 in the third region 105 and affecting the passivation effect of the second doped portion 12, thereby also improving the reliability of the back contact battery.

[0126] Accordingly, another aspect of this application embodiment also provides a stacked battery. The stacked battery includes the back contact battery described in any of the above embodiments or a back contact battery prepared by any of the above methods. It should be noted that the parts that are the same as or corresponding to the foregoing embodiments can be referred to the corresponding descriptions of the foregoing embodiments, and will not be repeated below.

[0127] Figure 11 This is a schematic diagram of a stacked battery provided in an embodiment of this application.

[0128] refer to Figure 11 The stacked battery includes a bottom cell 30 and a perovskite cell 31. The bottom cell 30 is a back contact cell in any of the foregoing embodiments, or the bottom cell is a back contact cell prepared by the preparation method of the back contact cell in any of the foregoing embodiments. The perovskite cell 31 is located on one side of the bottom cell 30.

[0129] Figure 12 This is a schematic diagram of another structure of the stacked battery provided in the embodiments of this application.

[0130] refer to Figure 12 In some embodiments, the perovskite solar cell 31 may include: a first transport layer 311, a perovskite functional layer 312, a second transport layer 313, a transparent conductive layer 314, and an anti-reflection layer 315 stacked together. The first transport layer 311 is directly opposite the bottom solar cell 30.

[0131] In some examples, the first transport layer 311 can be one of an electron transport layer and a hole transport layer, and the second transport layer 313 can be the other of an electron transport layer and a hole transport layer.

[0132] In some embodiments, the band gap width of the perovskite cell 31 is greater than that of the bottom cell 30. Therefore, stacking the perovskite cell 31 on top of the bottom cell 30 can give the stacked cell a wider spectral response range, thereby maximizing the utilization of solar energy and improving the efficiency of the cell.

[0133] In some embodiments, the stacked battery may further include an intermediate connecting layer (not shown) for electrically connecting the bottom battery 30 and the perovskite battery 31.

[0134] In some embodiments, the intermediate connecting layer is generally a tunnel junction or a very thin metal or transparent electrode composite layer. Optionally, the intermediate connecting layer can be a transparent conductive oxide, which has good optoelectronic properties, high photon transmittance and high conductivity, thereby enabling the perovskite cell 31 and the bottom cell 30 to maintain good ohmic contact.

[0135] In some embodiments, the tandem battery can be configured as a 2T (two-terminal series / two-terminal stacked) structure or a 4T (four-terminal series / four-terminal stacked) structure. The tandem battery can also be configured as a 3T (three-terminal series / three-terminal stacked) structure. The three-terminal stacked structure is mainly used in tandem batteries manufactured by combining back-contact batteries and perovskite batteries, and it produces three electrodes. In the four-terminal stacked battery, the two sub-cells are manufactured independently, and they are only optically connected; their circuits are independent. It can be understood that the perovskite battery 31 and the bottom battery 30 are merely physically stacked, and in reality, they each output independently. Therefore, the four-terminal stacked battery will have two positive electrodes and two negative electrodes.

[0136] Accordingly, in another aspect, this application also provides a photovoltaic module, which includes a back contact cell as described in any of the above embodiments, or a back contact cell prepared by the preparation method of the back contact cell in any of the embodiments, or a tandem cell as described in the above embodiments. It should be noted that the parts that are the same as or corresponding to the foregoing embodiments can be referred to the corresponding descriptions of the foregoing embodiments, and will not be repeated below.

[0137] Figure 13 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in an embodiment of this application.

[0138] refer to Figure 13The photovoltaic module includes: a cell string, which is formed by connecting multiple back-contact cells 40 as described above, or by connecting back-contact cells 40 prepared by the method for preparing back-contact cells according to any of the above embodiments, or by connecting multiple stacked cells as described in the above embodiments. The photovoltaic module also includes an encapsulation layer 41 and a cover plate 42; the encapsulation layer 41 is used to cover the surface of the cell string; the cover plate 42 is used to cover the surface of the encapsulation layer opposite to the cell string.

[0139] In some embodiments, the back contact battery 40 can be electrically connected in the form of a whole cell or sliced ​​cells to form multiple battery strings, which are electrically connected in series and / or parallel. A sliced ​​cell refers to a cell formed by cutting a complete whole cell. Segmented cells can be two-slice cells, three-slice cells, or four-slice cells, etc.

[0140] Multiple back-contact batteries 40 can be electrically connected through solder strips 43.

[0141] In some embodiments, the encapsulation layer 41 includes a first encapsulation sublayer and a second encapsulation sublayer. The first encapsulation sublayer covers one of the first and second surfaces of the back contact battery 40, and the second encapsulation sublayer covers the other of the first and second surfaces of the back contact battery 40. Specifically, at least one of the first and second encapsulation sublayers can be an organic encapsulation layer such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate (EVA) film, polyethylene octene elastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first and second encapsulation sublayers can also be an EP film, EPE film, or PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film; EPE film refers to a co-extruded film formed by sequentially stacking EVA film, POE film, and EVA film; and PVP film refers to a co-extruded film formed by stacking POE film, EVA film, and POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0142] In some cases, the first encapsulation sublayer and the second encapsulation sublayer still have a boundary line before lamination. After lamination, the photovoltaic module will no longer have the concept of the first encapsulation sublayer and the second encapsulation sublayer. That is, the first encapsulation sublayer and the second encapsulation sublayer have formed an integral encapsulation layer 41.

[0143] In some embodiments, the cover plate 42 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulation layer 41 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 42 may include a first cover plate 421 and a second cover plate 422, wherein the first cover plate 421 is opposite to the first encapsulation sub-layer, and the second cover plate 422 is opposite to the second encapsulation sub-layer.

[0144] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A back-contact battery, characterized in that, include: The substrate includes a first surface and a second surface, the second surface being divided into a first region, a second region and a third region located between the first region and the second region, the second region being recessed relative to the first region toward the first surface, and the third region being inclined relative to the first region; A first doped portion, wherein the first doped portion is located in the first region; A second doped portion, wherein the second doped portion is at least partially located in the second region and the third region; An insulating material layer, wherein the insulating material layer is at least partially located on the surface of the second doped portion of the third region away from the substrate; The first electrode is electrically connected to the first doped portion; The second electrode is electrically connected to the second doped portion.

2. The back contact battery according to claim 1, characterized in that, The second zone includes: In the first sub-region, the second electrode is located at least on the side of the second doped portion of the first sub-region away from the substrate; The second sub-region is located on at least one side of the first sub-region and is adjacent to the third region; The insulating material layer is also located on the side of the first doped portion of the second sub-region that is away from the substrate.

3. The back contact battery according to claim 1 or 2, characterized in that, The second doped portion located in the third region has a first pyramid structure on the surface facing away from the substrate.

4. The back contact battery according to claim 3, characterized in that, The insulating material layer covers the first apex of the first pyramid structure; the distance between the surface of the insulating material layer on the first apex, which is opposite to the substrate, and the first apex is less than or equal to 20 μm.

5. The back contact battery according to claim 3, characterized in that, The insulating material layer is exposed at the first apex of the first pyramid structure; the height of the portion of the first pyramid structure not covered by the insulating material layer is the first height, and the ratio of the first height to the height of the first pyramid structure is less than or equal to 0.

5.

6. The back contact battery according to claim 5, characterized in that, The first height is less than or equal to 4 μm; the height of the first pyramid structure is 2 μm to 8 μm.

7. The back contact battery according to claim 2, characterized in that, The second doped portion located in the second sub-region has a second pyramid structure on the surface facing away from the substrate.

8. The back contact battery according to claim 7, characterized in that, The insulating material layer covers the second apex of the second pyramid structure; the distance between the surface of the insulating material layer on the second apex, which is away from the substrate, and the second apex is less than or equal to 1 μm.

9. The back contact battery according to claim 7, characterized in that, The insulating material layer is exposed at the second apex of the second pyramid structure; the height of the portion of the second pyramid structure not covered by the insulating material layer is the second height, and the ratio of the second height to the height of the second pyramid structure is less than or equal to one-third.

10. The back contact battery according to claim 9, characterized in that, The second height is less than or equal to 0.7 μm; the height of the second pyramid structure is 0.4 μm to 2.2 μm.

11. The back contact battery according to claim 1 or 2, characterized in that, The first region includes: The third sub-region, wherein the first electrode is located at least on the side of the first doped portion of the first sub-region away from the substrate; The fourth sub-region is located on at least one side of the third sub-region and is adjacent to the third sub-region; The insulating material layer is also located on the side of the first doped portion of the fourth sub-region that is away from the substrate.

12. The back contact battery according to claim 11, characterized in that, The thickness of the insulating material layer on the side of the first doped portion located in the fourth sub-region away from the substrate is 0.1 μm to 20 μm.

13. The back contact battery according to claim 1, characterized in that, The insulating material layer is an insulating adhesive layer.

14. The back contact battery according to claim 1, characterized in that, The back contact battery also includes: A first conductive layer is located on the side of the first doped portion in the first region away from the substrate and is electrically connected to the first electrode. The second conductive layer is located on the side of the second doped portion in the second region away from the substrate and is electrically connected to the second electrode. The insulating material layer is spaced apart from the first conductive layer; the insulating material layer is also spaced apart from the second conductive layer.

15. A method for preparing a back-contact battery, characterized in that, include: A substrate is obtained, the substrate including a first surface and a second surface, the second surface being divided into a first region, a second region and a third region located between the first region and the second region, the second region being recessed relative to the first region toward the first surface, the third region being inclined relative to the first region, a first doped portion being formed on the first region, and a second doped portion being formed on at least the second region and the third region; An insulating material layer is formed, wherein the insulating material layer is at least partially located on the surface of the second doped portion of the third region away from the substrate; A first electrode and a second electrode are formed, wherein the first electrode is electrically connected to the first doped portion, and the second electrode is electrically connected to the second doped portion.

16. A stacked battery, characterized in that, include: The bottom battery is a back contact battery as described in any one of claims 1 to 14, or a back contact battery prepared by the method for preparing a back contact battery as described in claim 15. A perovskite solar cell, wherein the perovskite solar cell is located on one side of the bottom solar cell.

17. A photovoltaic module, characterized in that, include: The battery string is formed by connecting multiple back contact batteries as described in any one of claims 1 to 14, or by connecting multiple back contact batteries prepared by the method for preparing back contact batteries as described in claim 15, or by connecting multiple stacked batteries as described in claim 16. An encapsulation layer is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulation layer that faces away from the battery string.

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