A solar cell, photovoltaic module and laminated cell

Abstract

This application relates to the field of photovoltaic cell technology, and more particularly to a solar cell, a photovoltaic module, and a tandem cell. The solar cell includes a silicon substrate with a first surface and a second surface disposed opposite to each other. A plurality of first doped layers and a plurality of second doped layers are spaced apart on the first surface. A recess is formed within the first doped layer, and a doped contact portion with a polarity opposite to that of the first doped layer is formed within the recess, with the first doped layer contacting the doped contact portion. In this application, the first doped layer forms a recess, and the recess contains a doped contact portion with a polarity opposite to that of the first doped layer. This creates a local conductive path between the first doped layer and the doped contact portion, thereby forming a bypass point at the recess. This can reduce the reverse breakdown voltage when the back contact cell is shaded, thereby improving the hot spot resistance of the solar cell and mitigating the hot spot phenomenon caused by poor local conductivity in the solar cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cell technology, and in particular to a solar cell, a photovoltaic module, and a tandem cell. Background Technology

[0002] Currently, in solar cells, back-contact cells are cells in which both the emitter and base contact electrodes are placed on the back of the cell (the non-light-receiving surface). The light-receiving surface of this cell is not blocked by any metal electrodes, which effectively increases the short-circuit current of the cell.

[0003] When a back-contact battery is in use, if an obstruction in the external environment blocks the solar cell, the blocked solar cell will develop a hot spot phenomenon. This effect can severely damage the solar cell. At the same time, the energy generated by the solar cell that is exposed to sunlight may also be consumed by the blocked solar cell. Summary of the Invention

[0004] This application provides a solar cell, a photovoltaic module, and a tandem cell, which aim to improve the hot spot effect of solar cells.

[0005] This application provides a solar cell, which includes a silicon substrate. The silicon substrate has a first surface and a second surface disposed opposite to each other. A plurality of first doped layers and a plurality of second doped layers are disposed at intervals on the first surface.

[0006] The first doped layer has a recessed portion, and a doped contact portion with the opposite polarity to the first doped layer is formed in the recessed portion, and the first doped layer contacts the doped contact portion.

[0007] In one possible design, there is a spacer region between the first doped layer and the second doped layer;

[0008] The minimum spacing between the doped contact portion and the second doped layer is the width of the spacing region.

[0009] In one possible design, the area ratio of the recess to the first doped layer is a, where 0.05% ≤ a ≤ 5%.

[0010] In one possible design, the one-dimensional dimension of the recess is b, where 0.5μm ≤ b ≤ 240μm.

[0011] In one possible design, the solar cell further includes a first electrode stacked on the first doped layer;

[0012] Along the thickness direction of the solar cell, the projection surface of the doped contact portion on the first surface does not coincide with the projection surface of the first electrode on the first surface.

[0013] In one possible design, the doped contacts are uniformly distributed in the first doped layer.

[0014] In one possible design, the doped contact covers at least a portion of the sidewall of the recess along a direction perpendicular to the thickness of the solar cell.

[0015] In one possible design, the recess does not penetrate the first doped layer, and the doped contact covers the bottom wall of the recess.

[0016] In one possible design, the recess extends through the first doped layer, and a portion of the silicon substrate is exposed from the recess;

[0017] The doped contact covers the silicon substrate exposed from the recess.

[0018] In a second aspect, this application also provides a photovoltaic module, which includes a first cover plate, a first encapsulant film, a battery string, a second encapsulant film, and a second cover plate stacked together.

[0019] The battery string includes multiple electrically connected solar cells, which are the solar cells described above.

[0020] In a third aspect, this application also provides a stacked battery, which includes a top battery, an intermediate connecting layer, and a bottom battery, wherein the intermediate connecting layer connects the top battery and the bottom battery.

[0021] The top cell is one of a perovskite cell, a cadmium telluride solar cell, a copper indium gallium selenide solar cell, or a gallium arsenide solar cell, and the bottom cell is one of the aforementioned solar cells.

[0022] The technical effect of this application embodiment is that: the first doped layer has a recessed portion, the recessed portion has a doped contact portion, and the polarity of the doped contact portion is opposite to that of the first doped layer, so that the first doped layer and the doped contact portion form a local conductive path, thereby forming a bypass point at the recessed portion, which can reduce the reverse breakdown voltage when the back contact cell is blocked, thereby improving the hot spot resistance of the solar cell and improving the hot spot phenomenon caused by poor local conductivity of the solar cell.

[0023] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the photovoltaic module provided in this application;

[0025] Figure 2A schematic cross-sectional view of the solar cell provided in this application;

[0026] Figure 3 This is a schematic diagram showing the distribution of the first doped layer and the second doped layer provided in this application;

[0027] Figure 4 A schematic diagram showing the distribution of doped contacts on the first doped layer provided in this application;

[0028] Figure 5 This is a schematic diagram showing the distribution of doped contacts on the first doped layer provided in this application in another embodiment;

[0029] Figure 6 This is a cross-sectional schematic diagram of the solar cell structure provided in this application;

[0030] Figure 7 This is a cross-sectional schematic diagram of a portion of the solar cell structure provided in this application in another embodiment;

[0031] Figure 8 This is a cross-sectional schematic diagram of a portion of the solar cell structure provided in this application in another embodiment;

[0032] Figure 9 This is a cross-sectional schematic diagram of a portion of the solar cell structure provided in this application in another embodiment;

[0033] Figure 10 This is a cross-sectional schematic diagram of a portion of the solar cell structure provided in this application in another embodiment.

[0034] Figure label:

[0035] 10- Photovoltaic modules;

[0036] 101 - First cover plate;

[0037] 102 - First adhesive film;

[0038] 103-Battery string;

[0039] 104 - Second film;

[0040] 105 - Second cover plate;

[0041] 1-Solar cell;

[0042] 11-Silicon substrate;

[0043] 11a - First page;

[0044] 11b - Second page;

[0045] 111 - First doped layer;

[0046] 111a - Recessed portion;

[0047] 111b - Doped contact;

[0048] 112 - Second doped layer;

[0049] 113-Interval Zone;

[0050] 114 - First electrode;

[0051] 115 - Second electrode;

[0052] 116 - Tunneling oxide layer;

[0053] 117 - Backside passivation layer;

[0054] 118 - Front passivation layer.

[0055] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0056] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0057] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0058] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0059] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0060] It should be noted that the directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0061] In the field of photovoltaic power generation technology, photovoltaic modules are the core components that convert solar energy into electrical energy. Figure 1 The diagram shows the structure of a photovoltaic module 10. The photovoltaic module 10 includes a first cover plate 101, a first encapsulant film 102, a battery string 103, a second encapsulant film 104, and a second cover plate 105 stacked along its thickness direction Z. The first cover plate 101 and the battery string 103 are sealed and fixed together by the first encapsulant film 102, and the second cover plate 105 and the battery string 103 are sealed and fixed together by the second encapsulant film 104.

[0062] Specifically, the first cover plate 101 and / or the second cover plate 105 can be photovoltaic glass with high light transmittance, such as double-coated glass. The first cover plate 101 and the second cover plate 105 are used to protect the internal encapsulation material and the battery string 103 from mechanical damage and external environmental corrosion, and have waterproof and moisture-proof capabilities. During the lamination process of the photovoltaic module 10, the first encapsulant film 102 and the second encapsulant film 104 are used to encapsulate the battery string 103, preventing the external environment from affecting the performance of the battery string 103, and at the same time, they can also bond the first cover plate 101, the battery string 103 and the second cover plate 105 into a whole.

[0063] The battery string 103 can be one or more. If there are multiple battery strings 103, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery strings 103 are connected in both series and parallel, which can provide higher voltage and capacity. One end of the busbar is connected to the battery string 103, and the other end is connected to the junction box to lead out the electrical energy generated by the photovoltaic module 10 and connect it to an external load.

[0064] The materials of the first film 102 and the second film 104 can be one of the following: ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), polyvinyl butyral (PVB), etc., or they can be EPE film (EVA-POE-EVA co-extrusion structure) or EP film (EVA-EP co-extrusion structure).

[0065] It is understood that other layers may be provided between the first cover plate 101 and the first adhesive film 102, between the first adhesive film 102 and the battery string 103, between the battery string 103 and the second adhesive film 104, and between the second adhesive film 104 and the second cover plate 105. The specific number of layers of the photovoltaic module 10 can be set according to the actual situation, and this embodiment does not limit it.

[0066] In this embodiment, the photovoltaic module 10 connects individual solar cells 1 in series and parallel, encapsulates them, and connects them with external wires to form a solar cell module 1 that can be used independently as a photovoltaic power source. The photovoltaic module 10 absorbs sunlight and uses the photovoltaic effect to directly convert solar radiation energy into the required electrical energy output.

[0067] Figure 2 This is a cross-sectional schematic diagram of solar cell 1. Solar cell 1 includes a silicon substrate 11. Along the thickness direction Z of solar cell 1, silicon substrate 11 has a first surface 11a and a second surface 11b disposed opposite to each other.

[0068] In some embodiments, the material of the silicon substrate 11 can be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon. The elemental semiconductor material can be monocrystalline, polycrystalline, amorphous, or microcrystalline (possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon can be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0069] In some embodiments, the silicon substrate 11 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type element, which can be any one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type element, which can be any one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0070] In some embodiments, the first surface 11a of the silicon substrate 11 can be the back surface, and the second surface 11b can be the front surface. When the solar cell 1 is a single-sided cell, the second surface 11b can be the light-receiving surface for receiving incident light, and the first surface 11a serves as the back surface. When the solar cell 1 is a bifacial cell, both the first surface 11a and the second surface 11b of the silicon substrate 11 can serve as light-receiving surfaces and can be used to receive incident light. The first surface 11a can also receive incident light, but its efficiency in receiving incident light is somewhat lower than that of the second surface 11b.

[0071] The second surface 11b has a textured surface, which is a regular pyramidal textured surface. The sloping surface of the textured surface can increase the internal reflection of incident light, thereby improving the absorption and utilization rate of incident light by the silicon substrate 11, and thus improving the cell efficiency of the solar cell 1.

[0072] Please continue to refer to this. Figure 2 A tunneling oxide layer 116 is disposed on the side of the first surface 11a facing away from the silicon substrate 11. Multiple first doped layers 111 and second doped layers 112 are disposed at intervals on the side of the tunneling oxide layer 116 facing away from the silicon substrate 11, with a spacer region 113 between the first doped layers 111 and the second doped layers 112. A back passivation layer 117 is disposed on the side of the first doped layer 111 facing away from the silicon substrate 11, the side of the second doped layer 112 facing away from the silicon substrate 11, and the spacer region 113. A first electrode 114 and a second electrode 115 are also disposed on the first surface 11a. A portion of the structure of the first electrode 114 penetrates the back passivation layer 117 and is electrically connected to the first doped layer 111. A portion of the structure of the second electrode 115 penetrates the back passivation layer 117 and is electrically connected to the second doped layer 112.

[0073] The first electrode 114 and the second electrode 115 are fine grids of the solar cell 1, used to collect and summarize the current of the solar cell 1. The first electrode 114 and the second electrode 115 can be sintered from burn-through paste.

[0074] Specifically, the first electrode 114 and the second electrode 115 can be formed by: printing a metal paste on the surface of the back passivation layer 117 using a screen printing process, and then performing a sintering process on the metal paste. The metal paste contains glass powder or highly corrosive materials. In this way, during the sintering process, the corrosive components will corrode the back passivation layer 117, thereby allowing the metal paste to penetrate into the back passivation layer 117 and make electrical contact with the first doped layer 111 or the second doped layer 112.

[0075] The metal paste may include at least one of silver, aluminum, copper, tin, gold, lead, or nickel.

[0076] Please continue to refer to this. Figure 2 A front passivation layer 118 is provided on the side of the second surface 11b that is opposite to the silicon substrate 11.

[0077] Figure 3This is a schematic diagram showing the distribution of the first doped layer 111 and the second doped layer 112. A spacer region 113 exists between the first doped layer 111 and the second doped layer 112 to achieve automatic isolation between regions of different conductivity types. This can eliminate leakage current caused by the formation of a tunnel junction between the heavily doped P-region and N-region on the back of the solar cell 1, thus preventing it from affecting cell efficiency. Furthermore, the first doped layer 111 is electrically connected to the first electrode 114, and the second doped layer 112 is electrically connected to the second electrode 115.

[0078] It is understandable that the first doped layer 111 can be an N-type doped layer and the second doped layer 112 can be a P-type doped layer. Alternatively, the first doped layer 111 can be a P-type doped layer and the second doped layer 112 can be an N-type doped layer. The specific configuration can be set according to the actual situation, as long as the polarities of the first doped layer 111 and the second doped layer 112 are opposite. This embodiment does not impose any limitations on this.

[0079] Figure 4 This is a schematic diagram showing the distribution of doped contact portions 111b on the first doped layer 111 in one embodiment. Figure 5 This is a schematic diagram showing the distribution of doped contact portions 111b on the first doped layer 111 in another embodiment. Please refer to the reference. Figure 4 and Figure 5 A recessed portion 111a is provided in the first doped layer 111, and a doped contact portion 111b with the opposite polarity to the first doped layer 111 is formed in the recessed portion 111a, and the first doped layer 111 contacts the doped contact portion 111b.

[0080] The recess 111a can be a trench structure formed in the first doped layer 111, meaning that the recess 111a does not completely penetrate the first doped layer 111 along the thickness direction Z of the solar cell 1. Alternatively, the recess 111a can also be a hole structure formed in the first doped layer 111, meaning that the recess 111a completely penetrates the first doped layer 111 along the thickness direction Z of the solar cell 1. The specific design can be determined according to actual conditions, and this embodiment does not impose any limitations.

[0081] In this embodiment, a recess 111a is formed on the first doped layer 111, and a doped contact 111b is provided in the recess 111a. The polarity of the doped contact 111b is opposite to that of the first doped layer 111, so that the first doped layer 111 and the doped contact 111b form a local conductive path, thereby forming a bypass point at the recess 111a. This can reduce the reverse breakdown voltage of the solar cell 1 when it is shaded, thereby improving the hot spot resistance of the solar cell 1 and improving the hot spot phenomenon caused by poor local conductivity of the solar cell 1.

[0082] It should be noted that the orthographic projection of the recessed portion 111a onto the first surface 11a can be circular, polygonal, or irregular in shape. The specific shape can be determined according to the actual situation, and this embodiment does not impose any limitations.

[0083] Please refer to the reference. Figure 3 , Figure 4 and Figure 5 A spacer region 113 is provided between the first doped layer 111 and the second doped layer 112, and the minimum distance between the doped contact portion 111b and the second doped layer 112 is the width of the spacer region 113. That is, although the polarity of the doped contact portion 111b is opposite to that of the first doped layer 111, there is no contact between the doped contact portion 111b and the second doped layer 112, i.e., the doped contact portion 111b is not an extension structure from the second doped layer 112 to the first doped layer 111.

[0084] Please continue to refer to the reference. Figure 4 and Figure 5 Along the thickness direction Z of the solar cell 1, the projection surface of the doped contact portion 111b on the first surface 11a does not coincide with the projection surface of the first electrode 114 on the first surface 11a. That is to say, the doped contact portion 111b does not overlap with the first electrode 114, and the doped contact portion 111b in the first doped layer 111 has no contact with the first electrode 114, thus not introducing additional metal recombination loss.

[0085] Please continue to refer to this. Figure 5 In some embodiments, the doped contact portions 111b are uniformly distributed in the first doped layer 111. That is, the doped contact portions 111b are arranged in an array in the first doped layer 111. By arranging the doped contact portions 111b in an array, corresponding local conductive path structures exist at various locations in the first doped layer 111 of the solar cell 1, thereby improving the hot spot phenomenon of the solar cell 1.

[0086] In this embodiment, the recessed portion 111a can be formed into a nearly uniform distribution through patterning methods such as masking, ink processing, and laser processing, thereby enabling more controllable local conductivity and heat dissipation spots. Furthermore, the recessed portion 111a can be completely avoided from the area of ​​the first electrode 114, thus preventing metal composite loss.

[0087] Taking laser technology as an example, the formation of the first doped layer 111 and the second doped layer 112 can be as follows: first, the first doped layer 111 is formed on the side of the tunneling oxide layer 116 away from the silicon substrate 11; then, part of the first doped layer 111 is removed by local laser; then, the second doped layer 112 is formed in the area where the first doped layer 111 has been removed; then, etching and acid washing are performed to form a spacer region 113 between the first doped layer 111 and the second doped layer 112.

[0088] Based on the formation of the first doped layer 111 and the second doped layer 112, the recess 111a can be formed as follows: the first doped layer 111 is formed on the side of the tunneling oxide layer 116 away from the silicon substrate 11, and then part of the first doped layer 111 is removed by local laser, and the recess 111a can be formed in the first doped layer 111 by laser.

[0089] Alternatively, the recess 111a can be formed by: forming a first doped layer 111 on the side of the tunneling oxide layer 116 facing away from the silicon substrate 11, and then removing part of the first doped layer 111 by local laser removal while forming the recess 111a inside the first doped layer 111. The specific configuration can be determined according to the design, and this embodiment does not limit it.

[0090] It is understandable that the methods for forming the recessed portion using ink technology and mask technology can be referred to above, and will not be repeated here in this embodiment.

[0091] Based on the formation method of the first doped layer 111 and the second doped layer 112, the doped contact portion 111b can be formed as follows: while forming the second doped layer 112 in the area where the first doped layer 111 has been removed, the doped contact portion 111b is formed in the recessed portion 111a. That is, the doped contact portion 111b is made of the same material as the second doped layer 112, and the polarity of the doped contact portion 111b is opposite to that of the first doped layer 111.

[0092] Please continue to refer to this. Figure 4 It is understandable that in some embodiments, the doped contact portion 111b may also be non-uniformly distributed in the first doped layer 111.

[0093] It is understandable that some of the recesses 111a may also be formed randomly during the fabrication of the solar cell 1. For example, the recesses 111a may be formed in the first doped layer 111 due to high-temperature processes and subsequent wet processes.

[0094] It should be noted that even if some of the recesses 111a can be randomly formed during the fabrication of the solar cell 1, the local conductive path formed by the doped contact 111b and the first doped layer 111 after the doped contact 111b is formed within the recesses 111a cannot meet the requirements for reducing hot spots. Therefore, in this embodiment, recesses 111a are further provided within the first doped layer 111, and doped contact 111b is formed within the recesses 111a to further reduce the hot spot phenomenon.

[0095] In some embodiments, the area ratio of the recess 111a to the area of ​​the first doped layer 111 is a, where 0.05% ≤ a ≤ 5%. That is, the ratio of the area of ​​the recess 111a projected onto the first doped layer 111 to the area of ​​the first doped layer 111 is 0.05%-5%.

[0096] For example, the ratio of the area of ​​the recess 111a projected onto the first doped layer 111 to the area of ​​the first doped layer 111 can be 0.05%, 0.1%, 0.25%, 0.5%, 0.75%, 1%, 1.25%, 1.5%, 1.75%, 2%, 2.25%, 2.5%, 2.75%, 3%, 3.25%, 3.5%, 3.75%, 4%, 4.25%, 4.5%, 4.75%, 5%, etc., and can be set according to the actual situation. This embodiment does not limit it.

[0097] In this embodiment, the larger the ratio of the area of ​​the recess 111a projected onto the first doped layer 111 to the area of ​​the first doped layer 111, the more contact surfaces there are between the doped contact portion 111b within the recess 111a and the first doped layer 111, resulting in better local conductivity. Conversely, the smaller the ratio of the area of ​​the recess 111a projected onto the first doped layer 111 to the area of ​​the first doped layer 111, the fewer contact surfaces there are between the doped contact portion 111b within the recess 111a and the first doped layer 111, thus reducing the ability of the doped contact portion 111b to affect the efficiency of the solar cell 1. Therefore, by setting the area ratio of the recess 111a to the area of ​​the first doped layer 111 to 0.05%-5%, the local conductivity of the solar cell 1 can be improved while avoiding affecting its photoelectric conversion efficiency.

[0098] Furthermore, the ratio of the area of ​​the recess 111a projected onto the first doped layer 111 to the area of ​​the first doped layer 111 is 0.3%-1.5%.

[0099] For example, the ratio of the area of ​​the recess 111a projected onto the first doped layer 111 to the area of ​​the first doped layer 111 can be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, etc., or the ratio can be increased or decreased according to the actual situation. The specific ratio can be set according to the actual situation, and this embodiment does not limit it.

[0100] In some embodiments, the one-dimensional dimension of the recess 111a is b, where 0.5μm≤b≤240μm.

[0101] For example, the one-dimensional dimension of the recess 111a can be 0.5μm, 20μm, 40μm, 60μm, 80μm, 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, 220μm, 240μm, etc., and can be set according to the actual situation. This embodiment does not limit it.

[0102] In this embodiment, the larger the one-dimensional dimension of the recess 111a, the more contact surfaces there are between the doped contact portion 111b within the recess 111a and the first doped layer 111, resulting in better local conductivity. Conversely, the smaller the one-dimensional dimension of the recess 111a, the fewer contact surfaces there are between the doped contact portion 111b within the recess 111a and the first doped layer 111, and the lower the ability of the doped contact portion 111b to affect the efficiency of the solar cell 1. Therefore, by setting the one-dimensional dimension of the recess 111a to 0.5μm-240μm, the local conductivity efficiency of the solar cell 1 can be improved while avoiding affecting the photoelectric conversion efficiency of the solar cell 1.

[0103] The shape of the recess 111a projected onto the first doped layer 111 can be circular, rectangular, elliptical, triangular, etc. The one-dimensional dimension of the recess 111a can be the diameter of a circle, the side length of a rectangle or triangle, the side length of an ellipse, etc., and the one-dimensional dimension of the recess 111a can also be the line connecting two corners, etc.

[0104] Figure 6 This is a schematic diagram in one embodiment when a doped contact portion 111b is formed within a recess 111a in the first doped layer 111. Figure 7 This is a schematic diagram in another embodiment when a doped contact portion 111b is formed within a recess 111a in the first doped layer 111. Figure 8 This is a schematic diagram in another embodiment when a doped contact portion 111b is formed within a recess 111a in the first doped layer 111. Figure 9 This is a schematic diagram of another embodiment where a doped contact portion 111b is formed within a recess 111a in the first doped layer 111. Please refer to the reference. Figure 6 , Figure 7 , Figure 8 and Figure 9 Along the thickness direction Z perpendicular to the solar cell 1, the doped contact portion 111b covers at least a portion of the sidewall of the recessed portion 111a.

[0105] In this embodiment, the doped contact portion 111b can completely cover all sidewalls and bottom wall surfaces of the recessed portion 111a. Alternatively, the doped contact portion 111b can cover part of the sidewalls but not the bottom wall surface. Alternatively, the doped contact portion 111b can cover part of the sidewalls and the entire bottom wall surface. Alternatively, the doped contact portion 111b can cover only part of the sidewalls and part of the bottom wall surface. Alternatively, the doped contact portion 111b can cover all sidewalls but not the bottom wall surface. The specific configuration can be determined according to actual conditions, and this embodiment does not impose any limitations.

[0106] It is understandable that when the first doped layer 111 forms a recess 111a, the recess 111a may not penetrate the first doped layer 111 or it may completely penetrate the first doped layer 111. The specific setting can be determined according to the actual situation, and this embodiment does not limit it here.

[0107] Please continue to refer to the following for details. Figure 6 The recess 111a does not penetrate the first doped layer 111, and the doped contact portion 111b covers the bottom wall of the recess 111a. That is, the recess 111a does not completely penetrate the first doped layer 111 in the thickness direction Z of the first doped layer 111, and the doped contact portion 111b covers at least a portion of the side wall surface of the recess 111a and at least a portion of the bottom wall surface of the recess 111a.

[0108] In this embodiment, the recess 111a is a groove structure that does not completely penetrate the first doped layer 111, and the doped contact 111b can form a local conductive path with the first doped layer 111 on the side wall and bottom wall of the recess 111a.

[0109] Alternatively, please continue to refer to Figure 7 The recess 111a penetrates the first doped layer 111, and a portion of the back passivation layer 117 is exposed from the recess 111a. The doped contact portion 111b covers the back passivation layer 117 exposed from the recess 111a. That is, the recess 111a completely penetrates the first doped layer 111 in the thickness direction Z of the first doped layer 111, and the doped contact portion 111b covers at least a portion of the sidewall surface of the recess 111a and a portion of the back passivation layer 117.

[0110] In this embodiment, the recess 111a is a hole structure that completely penetrates the first doped layer 111, and the doped contact 111b can form a local conductive path with the first doped layer 111 on the side wall of the recess 111a.

[0111] Alternatively, please continue to refer to Figure 8The recess 111a penetrates the first doped layer 111 and the back passivation layer 117, and a portion of the silicon substrate 11 is exposed from the recess 111a. The doped contact portion 111b covers the silicon substrate 11 exposed from the recess 111a. That is, the recess 111a completely penetrates the first doped layer 111 and the back passivation layer 117 in the thickness direction Z of the first doped layer 111, and the doped contact portion 111b covers at least a portion of the sidewall surface of the recess 111a and a portion of the silicon substrate 11.

[0112] In this embodiment, the recess 111a is a hole structure that completely penetrates the first doped layer 111, and the doped contact 111b can form a local conductive path with the first doped layer 111 on the side wall of the recess 111a.

[0113] Alternatively, please continue to refer to Figure 9 The recess 111a penetrates the first doped layer 111, the back passivation layer 117, and a portion of the silicon substrate 11, with the portion of the silicon substrate 11 exposed from the recess 111a. The doped contact portion 111b covers the exposed silicon substrate 11 from the recess 111a. That is, the recess 111a penetrates the first doped layer 111, the back passivation layer 117, and a portion of the silicon substrate 11 in the thickness direction Z of the first doped layer 111, and the doped recess 111a covers at least a portion of the sidewall surface of the recess 111a and a portion of the silicon substrate 11.

[0114] In this embodiment, the recess 111a is a hole structure that completely penetrates the first doped layer 111, and the doped contact 111b can form a local conductive path with the first doped layer 111 on the side wall of the recess 111a.

[0115] Figure 10 This is a schematic diagram in another embodiment where a doped contact portion 111b is formed within a recess 111a in the first doped layer 111. A silicon oxide layer is formed on the surface of the first doped layer 111. A second doped layer 112 is formed in the area where the first doped layer 111 is removed, and the doped contact portion 111b is formed within the recess 111a. These can be formed on the entire surface of the first doped layer 11a. In other words, a second doped layer 112 can be formed on the first doped layer 111, and the silicon oxide layer on the surface of the first doped layer 111 can isolate the first doped layer 111 and the second doped layer 112, preventing direct contact between the first doped layer 111 and the second doped layer 112 and simplifying the fabrication process.

[0116] This embodiment also provides a tandem solar cell, which includes a top cell, an intermediate connecting layer, and a bottom cell, with the intermediate connecting layer connecting the bottom cell and the top cell. The top cell is one of a perovskite solar cell, a cadmium telluride solar cell 1, a copper indium gallium selenide solar cell 1, or a gallium arsenide solar cell 1, and the bottom cell is the aforementioned solar cell 1.

[0117] The intermediate interconnect layer is typically selected from transparent materials with high refractive index. An effective intermediate interconnect layer needs high light transmittance to reduce light reflection and absorption at the interconnect layer interface, and good conductivity to reduce the impact of series resistance on device performance. For example, transparent conductive metal oxide thin films (ITO) can be used as intermediate interconnect layers.

[0118] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A solar cell, characterized in that, The solar cell (1) includes a silicon substrate (11), the silicon substrate (11) having a first surface (11a) and a second surface (11b) disposed opposite to each other, and a plurality of first doped layers (111) and a plurality of second doped layers (112) are disposed at intervals on the first surface (11a). The first doped layer (111) has a recess (111a) and a doped contact portion (111b) with the opposite polarity to the first doped layer (111) is formed in the recess (111a). The first doped layer (111) contacts the doped contact portion (111b). There is a spacer region (113) between the first doped layer (111) and the second doped layer (112). The minimum spacing between the doped contact portion (111b) and the second doped layer (112) is the width of the spacer region (113).

2. The solar cell according to claim 1, characterized in that, The area ratio of the recess (111a) to the area of ​​the first doped layer (111) is a, where 0.05% ≤ a ≤ 5%.

3. The solar cell according to claim 1, characterized in that, The one-dimensional dimension of the recess (111a) is b, where 0.5μm≤b≤240μm.

4. The solar cell according to claim 1, characterized in that, The solar cell (1) further includes a first electrode (114) stacked on the first doped layer (111). Along the thickness direction (Z) of the solar cell (1), the projection surface of the doped contact portion (111b) on the first surface (11a) does not coincide with the projection surface of the first electrode (114) on the first surface (11a).

5. The solar cell according to claim 1, characterized in that, The doped contact portion (111b) is uniformly distributed in the first doped layer (111).

6. The solar cell according to any one of claims 1 to 5, characterized in that, Along the thickness direction (Z) perpendicular to the solar cell (1), the doped contact (111b) covers at least a portion of the sidewall of the recess (111a).

7. The solar cell according to claim 6, characterized in that, The recess (111a) does not penetrate the first doped layer (111), and the doped contact (111b) covers the bottom wall of the recess (111a).

8. The solar cell according to claim 6, characterized in that, The recess (111a) penetrates the first doped layer (111), and a portion of the silicon substrate (11) is exposed from the recess (111a); The doped contact portion (111b) covers the silicon substrate (11) exposed from the recess portion (111a).

9. A photovoltaic module, characterized in that, The photovoltaic module (10) includes a first cover plate (101), a first encapsulant film (102), a battery string (103), a second encapsulant film (104), and a second cover plate (105) stacked together. The battery string (103) includes a plurality of electrically connected solar cells (1), wherein the solar cells (1) are any one of claims 1 to 8.

10. A stacked battery, characterized in that, The stacked battery includes a top battery, an intermediate connecting layer, and a bottom battery, wherein the intermediate connecting layer connects the top battery and the bottom battery. The top cell is one of a perovskite cell, a cadmium telluride solar cell, a copper indium gallium selenide solar cell, or a gallium arsenide solar cell, and the bottom cell is the solar cell (1) according to any one of claims 1 to 8.

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