Solar cell and method of manufacturing the same, photovoltaic module, and electric device

Abstract

The application relates to a solar cell, a preparation method thereof, a photovoltaic module and a power utilization device. The solar cell has a plurality of sub-cells, each of which comprises a first electrode layer, a photoelectric conversion assembly and a second electrode layer which are sequentially stacked along the thickness direction of the sub-cell. The second electrode layer comprises a main body part and a connecting part electrically connected with the main body part. The connecting part of one of the sub-cells is used to electrically connect the first electrode layer of another sub-cell, so that the plurality of sub-cells are electrically connected. The thickness of the main body part is greater than that of the connecting part. The photoelectric conversion efficiency of the solar cell can be improved.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to a solar cell and its preparation method, photovoltaic module and electrical device. Background Technology

[0002] Solar cells, which are photoelectric conversion devices that directly convert light energy into electrical energy, possess excellent photoelectric properties and simple fabrication methods, bringing new possibilities and hope to photovoltaic power generation.

[0003] In the production process of solar cells, how to further improve their photoelectric conversion efficiency is an urgent problem to be solved. Summary of the Invention

[0004] This application is made in view of the above-mentioned issues, and its purpose is to provide a solar cell, a method for preparing the same, a photovoltaic module, and an electrical device thereof, with the aim of improving the photoelectric conversion efficiency of the solar cell.

[0005] To achieve the above objectives, a first aspect of this application provides a solar cell having multiple sub-cells. Each sub-cell includes a first electrode layer, a photoelectric conversion component, and a second electrode layer sequentially stacked along its own thickness direction. The second electrode layer includes a main body and a connecting portion electrically connected to the main body. The connecting portion of one of the sub-cells is used to electrically connect to the first electrode layer of another sub-cell, so that the multiple sub-cells are electrically connected. The thickness of the main body is greater than the thickness of the connecting portion.

[0006] Therefore, in the embodiment of this application, when forming the structure of the sub-cell, by setting the thickness of the main body to be greater than the thickness of the connecting part, on the one hand, it can protect the photoelectric conversion component, reduce the risk of external water vapor and oxygen intruding into the photoelectric conversion component, and ensure the performance of the photoelectric conversion component, thereby ensuring the photoelectric conversion efficiency of the solar cell; on the other hand, when the second hollow part is etched, part of the main body can play a good role in heat conduction, the heat island at the edge of the structure of the second hollow part formed by etching is smaller, the structure of the sub-cell is more stable, and the photoelectric conversion efficiency of the solar cell can be improved.

[0007] In any embodiment, the ratio of the thickness of the main body to the thickness of the connecting part is A, where 1 < A ≤ 20; alternatively, 1 < A ≤ 10. When A satisfies the above range, the main body can not only provide good protection for the photoelectric conversion component, but also improve the photoelectric conversion efficiency of the solar cell.

[0008] In any embodiment, the main body is made of the same material; optionally, the material of the main body includes gold (Au), silver (Ag), copper (Cu), aluminum (Al), transparent conductive oxide (TCO), or carbon. The interior of the main body is essentially interface-free, which improves the overall structural stability of the main body.

[0009] In any embodiment, the main body includes a first part and a second part, the second part being located on the side of the first part facing away from the first electrode layer, and the first part and the second part being made of different materials; optionally, the materials of the first part and the second part are independently selected from gold (Au), silver (Ag), copper (Cu), aluminum (Al), transparent conductive oxide (TCO), or carbon. The first part can provide good protection for the photoelectric conversion component and can play a good role in thermal conduction during the scribing process; the second part can play a good role in electrical conductivity, which is beneficial to the transmission of electrons.

[0010] In any embodiment, the sub-cell includes a blocking layer for blocking first charge transport, the blocking layer being disposed between the photoelectric conversion component and the main body; optionally, the material of the blocking layer includes at least one of block copolymer BCP, lithium fluoride LiF, and tin oxide SnO2. The blocking layer can block the transport of holes at the interface of the photoelectric conversion component, thereby improving the transport efficiency of electrons from the photoelectric conversion component to the second electrode layer, and can reduce the risk of recombination of electrons and holes at the interface of the photoelectric conversion component, further improving the electron transport efficiency, thereby improving the photoelectric conversion efficiency of the solar cell.

[0011] In any embodiment, the weight ratio of the barrier layer to the main body is B, where 0.001 ≤ B ≤ 0.2; optionally, 0.005 ≤ B ≤ 0.1. When B meets the above range, in addition to the barrier layer's good hole-blocking effect, the main body can also provide good protection for the barrier layer, thereby improving the photoelectric conversion efficiency of the solar cell.

[0012] In any embodiment, the ratio of the thickness of the barrier layer to the thickness of the main body is C, where 0.005 ≤ C ≤ 0.2; optionally, 0.01 ≤ C ≤ 0.1. When C meets the above range, in addition to the barrier layer's good hole-blocking effect, the main body can also provide good protection for the barrier layer, thereby improving the photoelectric conversion efficiency of the solar cell.

[0013] In any embodiment, the photoelectric conversion component includes a first charge transport layer, a photoelectric conversion layer and a second charge transport layer stacked sequentially along the thickness direction of the sub-cell, wherein the first charge transport layer is located between the first electrode layer and the photoelectric conversion layer.

[0014] The first charge transport layer is made of at least one of the following materials: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]PTAA, polymer PEDOT (3,4-ethylenedioxythiophene monomer), nickel oxide NiOx, CuI, and Cu2O. The first charge transport layer is disposed between the first electrode layer and the photoelectric conversion layer, enabling the formation of a good ohmic contact, effective hole transport, reduced carrier recombination at the interface, and improved photoelectric conversion efficiency.

[0015] The photoelectric conversion layer is made of an ABX3 crystal structure, where A includes at least one of methylammonium (MA), formamide (FA), and cesium (Cs); B includes at least one of lead (Pb), tin (Sn), and copper (Cu); and X includes at least one of bromine (Br), chlorine (Cl), and iodine (I). The photoelectric conversion layer absorbs photons and converts them into electrons and holes, which are then transported to the first charge transport layer and the second charge transport layer, respectively, under the influence of a built-in electric field.

[0016] The material of the second charge transport layer includes at least one of C60, tin oxide (SnO2), fullerene derivative PCBM, and titanium oxide (TiO2). Placing the second charge transport layer between the photoelectric conversion layer and the second electrode layer can, on the one hand, reduce the energy level barrier between the photoelectric conversion layer and the second electrode layer, which is beneficial for electron transport and improves electron transport efficiency; on the other hand, the second charge transport layer itself facilitates electron transport, blocks holes, and reduces the risk of carrier recombination at the interface.

[0017] In any embodiment, the material of the first electrode layer includes gold (Au), silver (Ag), copper (Cu), aluminum (Al), transparent conductive oxide (TCO), or carbon. The first electrode layer using these materials exhibits good conductivity, which is beneficial for hole transport.

[0018] A second aspect of this application provides a photovoltaic module including a plurality of solar cells according to the embodiments of the first aspect of this application.

[0019] A third aspect of this application provides an electrical device including a plurality of photovoltaic modules according to embodiments of the second aspect of this application.

[0020] A fourth aspect of this application provides a method for fabricating a solar cell, the method comprising: providing a substrate; forming a bottom electrode on one side of the substrate, the bottom electrode including a plurality of first electrode layers spaced apart to divide the solar cell into a plurality of sub-cells; forming photoelectric conversion components on the surfaces of the plurality of first electrode layers opposite to the substrate; forming a second electrode layer on the surface of the photoelectric conversion components opposite to the substrate, the second electrode layer including a main body and a connecting portion electrically connected to the main body, wherein the connecting portion of one of the plurality of sub-cells is used to electrically connect to the first electrode layer of another sub-cell, so that the plurality of sub-cells are electrically connected, wherein the thickness of the main body is greater than the thickness of the connecting portion.

[0021] In any embodiment, the step of forming a second electrode layer on the surface of the photoelectric conversion component away from the substrate includes: forming a first portion on the surface of the photoelectric conversion component away from the substrate; sequentially removing the first portion and a portion of the photoelectric conversion component along the thickness direction of the sub-cell to form a hollow area; forming a second portion on the surface of the first portion away from the substrate, and forming a connecting portion in the hollow area, wherein the second portion and the first portion are made of different materials.

[0022] In any embodiment, a blocking layer is provided between the photoelectric conversion component and the second electrode layer, the blocking layer being used to block hole transmission. Attached Figure Description

[0023] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0024] Figure 1 These are schematic diagrams of the vehicle structure provided in some embodiments of this application; Figure 2 These are schematic block diagrams of photovoltaic modules provided in some embodiments of this application; Figure 3 These are schematic diagrams of the structure of solar cells provided in some embodiments of this application; Figure 4 yes Figure 3 An enlarged schematic diagram at point I; Figure 5 yes Figure 3 Another enlarged diagram at point I; Figure 6 These are schematic diagrams of the structure of solar cells provided in other embodiments of this application; Figure 7 yes Figure 6 An enlarged schematic diagram at point II; Figure 8 This is a schematic diagram of the structure of a solar cell provided in some embodiments of this application; Figure 9 This is a schematic diagram of the fabrication process of solar cells provided in some embodiments of this application; Figure 10 This is a schematic diagram of the fabrication process of a solar cell provided in some other embodiments of this application; Figure 11 This is a schematic diagram of the fabrication process of a solar cell provided in some embodiments of this application; The accompanying drawings may not be drawn to scale.

[0025] The following are the labeling elements in the figure: X, thickness direction; P1, first cutout section; P2, second cutout section; P3, third cutout section; 1. Vehicle; 2. Photovoltaic module; 3. Controller; 4. Motor; 5. Solar cells; 50. Substrate; 51. First electrode layer; 52. Photoelectric conversion component; 521. First charge transport layer; 522. Photoelectric conversion layer; 523. Second charge transport layer; 53. Second electrode layer; 531. Main body; 5311. First part; 5312. Second part; 532. Connecting part; 54. Barrier layer; 6. Sub-battery. Detailed Implementation

[0026] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0027] In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable tolerance range. "Parallel" is not parallel in the strict sense, but within the allowable tolerance range.

[0028] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0029] In this embodiment, the solar cell is a photoelectric conversion device that directly converts light energy into electrical energy based on the photovoltaic effect. The solar cell includes a photoelectric conversion component, a transport layer, and an electrode layer for photoelectric conversion. Because the photoelectric conversion component, transport layer, and electrode layer use different materials, and due to the differences in the quasi-Fermi levels of these materials, a built-in electric field is formed inside the photoelectric conversion device. The photoelectric conversion component, as the light-absorbing material of the solar cell, absorbs photons to generate electron-hole pairs, which are then separated into free charge carriers. These free charge carriers then drift in opposite directions under the influence of the built-in electric field: electrons move towards the negative electrode, and holes move towards the positive electrode. The electrons and holes are transported out by different transport layers and then collected by the electrode layer, thus creating a potential difference between the positive and negative electrodes, generating current, and completing the entire photoelectric conversion process.

[0030] The performance of a solar cell can be reflected by factors such as short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency.

[0031] Short-circuit current density refers to the current density when a solar cell is in a short-circuit state, that is, when the voltage across its terminals is zero. The short-circuit current is generated by the generation and collection of photogenerated carriers, and it is related to the optical characteristics of the solar cell itself, the frequency of the incident light source, interface loss, etc.

[0032] Open-circuit voltage refers to the potential difference between the two ends of a solar cell when the current flowing through the external circuit is zero and the circuit is in an open-circuit state.

[0033] The fill factor is the ratio of the maximum power of a solar cell to the product of its short-circuit current density and open-circuit voltage. A higher fill factor results in a lower series resistance and a higher parallel resistance in the solar cell.

[0034] Photovoltaic conversion efficiency (PVCE) refers to the ratio of a solar cell's maximum power output to the incident light power. By adjusting the short-circuit current density, open-circuit voltage, and fill factor, the PVCE of a solar cell can be effectively improved. For example, in the field of solar cells, PVCE is used to evaluate the performance of a solar cell; a larger fill factor results in higher PVCE and better solar cell performance.

[0035] For large-area solar cells, multiple sub-cells are obtained through scribing to achieve the required voltage and current output. For example, a first, second, and third scribing process can be used to divide and electrically connect (e.g., in series) the solar cells. The scribing process is as follows: a first electrode layer is formed on a substrate; a first cutout is scribed to divide the sub-cells; a photoelectric conversion module is formed on the side of the first electrode layer facing away from the substrate, and a second cutout is scribed to create the series channel between the sub-cells; a second electrode layer is formed on the side of the photoelectric conversion module facing away from the substrate, and a third cutout is scribed to divide the second electrode layer.

[0036] The sub-cell includes a power-generating region and a dead region. The dead region is located between the power-generating regions of two adjacent sub-cells, specifically the area between the first and third cutouts. The power-generating region refers to the area that can effectively utilize light and perform photoelectric conversion, such as the area where each sub-cell can perform photoelectric conversion. The dead region cannot utilize light, thus wasting light. There is contact resistance between the first and second electrode layers located in the dead region, and the photoelectric conversion component itself in the dead region has a certain resistance. These resistances constitute a series resistance. The larger the series resistance, the smaller the photocurrent; the smaller the series resistance, the smaller the photocurrent. Moreover, from another perspective, because the fill factor and series resistance are positively correlated, that is, the larger the series resistance, the lower the fill factor value, thereby reducing the photoelectric conversion efficiency; the smaller the series resistance, the higher the fill factor value, thereby increasing the photoelectric conversion efficiency.

[0037] The inventors discovered that for thin-film solar cells, which have a relatively large area, the etching process requires a certain amount of time. In particular, the relatively long etching time during the second etching process can cause external moisture and oxygen to penetrate into the cell, adversely affecting the performance of the solar cell.

[0038] In view of this, this application provides a technical solution in which a solar cell has multiple sub-cells. Each sub-cell includes a first electrode layer, a photoelectric conversion component, and a second electrode layer sequentially stacked along its own thickness direction. The second electrode layer includes a main body and a connecting portion electrically connected to the main body. The connecting portion of one of the sub-cells is used to electrically connect to the first electrode layer of another sub-cell, thereby electrically connecting the multiple sub-cells. The thickness of the main body is greater than the thickness of the connecting portion. Solar cells with this structure can significantly improve their photoelectric conversion efficiency.

[0039] The technical solutions described in the embodiments of this application are applicable to photovoltaic modules that include solar cells and electrical devices that use photovoltaic modules.

[0040] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0041] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0042] like Figure 1 As shown, a photovoltaic module 2 is installed inside the vehicle 1. The photovoltaic module 2 can be installed on the top, front, or rear of the vehicle 1. The photovoltaic module 2 can be used to power the vehicle 1; for example, the photovoltaic module 2 can serve as the operating power source for the vehicle 1.

[0043] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control photovoltaic module 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0044] like Figure 2 As shown, the photovoltaic module 2 includes a solar cell 5. There can be one or more solar cells 5. If there are multiple solar cells 5, they can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration means that multiple solar cells 5 can be connected in both series and parallel, which can provide higher voltage and capacity.

[0045] like Figure 3 and Figure 4 As shown, this application embodiment provides a solar cell 5, which has multiple sub-cells 6. Each sub-cell 6 includes a first electrode layer 51, a photoelectric conversion component 52, and a second electrode layer 53, which are sequentially stacked along their own thickness direction X. The second electrode layer 53 includes a main body portion 531 and a connecting portion 532 electrically connected to the main body portion 531. The connecting portion 532 of one of the multiple sub-cells 6 is used to electrically connect to the first electrode layer 51 of another sub-cell 6, so that the multiple sub-cells 6 are electrically connected. The thickness of the main body portion 531 is greater than the thickness of the connecting portion 532.

[0046] The solar cell 5 has multiple sub-cells 6 connected in series, which can improve the maximum output power of the solar cell 5 and significantly increase its fill factor. As the number of sub-cells 6 connected in series increases, its constant current effect can be improved, and the open circuit voltage can be increased, which can meet the needs of external loads.

[0047] It should be noted that each film layer in the sub-cell 6 is formed on the substrate 50. Using the substrate 50 as the supporting base, a first electrode layer 51 is pre-formed on the substrate 50. Then, a photoelectric conversion component 52 is formed on the side of the first electrode layer 51 facing away from the substrate 50, and a second electrode layer 53 is formed on the side of the photoelectric conversion component 52 facing away from the substrate 50. Exemplarily, the substrate 50, as the supporting base, has insulating properties and can be a flexible substrate or a rigid substrate. A rigid substrate may include a glass substrate; a flexible substrate may include polyethylene terephthalate (PEI) or polyimide (PI).

[0048] As the core functional layer of the sub-battery 6, the photoelectric conversion component 52's main function is to absorb external light, form electron-hole pairs within it, and then separate and extract the electrons and holes for output. For example, the photoelectric conversion component 52 can be a perovskite photoelectric conversion component, but it can also be other photoelectric conversion components 52, such as cadmium zinc telluride photoelectric conversion components, copper indium gallium selenide photoelectric conversion components, etc.

[0049] The photoelectric conversion component 52 may include multiple transmission layers for transmitting electrons and holes respectively; of course, the photoelectric conversion component 52 may also include a functional layer for improving the transmission efficiency of electrons and holes and reducing the risk of electron-hole recombination.

[0050] The first electrode layer 51 and the second electrode layer 53 are respectively used to electrically connect to the photoelectric conversion component 52. The first electrode layer 51 is used to collect holes, and the second electrode layer 53 is used to collect electrons. The first electrode layer 51 and the second electrode layer 53 can be made of the same material or different materials. For example, both the first electrode layer 51 and the second electrode layer 53 can be made of metal, or the first electrode layer 51 can be made of a transparent conductive material, and the second electrode layer 53 can be made of metal, etc. Metal materials have a large number of free electrons and their metallic conductivity is good; transparent conductive materials have both conductivity and light transmittance.

[0051] In an embodiment of this application, the second electrode layer 53 of one of two adjacent sub-cells 6 is connected to the first electrode layer 51, thereby achieving series connection between the two adjacent sub-cells 6. The second electrode layer 53 includes a main body 531 and a connecting portion 532, with the connecting portion 532 connected to the main body 531. The main body 531 of the sub-cell 6 is located on the side of the photoelectric conversion assembly 52 opposite to the first electrode layer 51. The connecting portion 532 of the sub-cell 6 penetrates the photoelectric conversion assembly 52, with one end of the connecting portion 532 connected to the main body 531 and the other end connected to the first electrode layer 51 of the other sub-cell 6.

[0052] When forming the second electrode layer 53, at least a portion of the main body 531 and the connecting portion 532 are integrally provided, and the main body 531 and the connecting portion 532 are mechanically connected, and electrical connection can also be achieved through mechanical connection.

[0053] The second electrode layer 53 can be made of one material or multiple materials.

[0054] When the second electrode layer 53 is made of a single material, a film layer of that material is pre-formed on the side of the photoelectric conversion component 52 facing away from the first electrode layer 51. Then, the film layer and the photoelectric conversion component 52 are etched to form a second hollow portion. Next, another film layer is formed within the second hollow portion and on the side of the film layer facing away from the first electrode layer 51, using the same material. Since the two film layers are made of the same material, there is no obvious interface between them.

[0055] When the second electrode layer 53 is made of multiple materials, for example, including a first material and a second material, a first film layer is formed by pre-setting the first material on the side of the photoelectric conversion component 52 away from the first electrode layer 51. Then, the first film layer and the photoelectric conversion component 52 are etched to form a second hollow portion P2. Then, the second material is set in the second hollow portion P2 and on the side of the first film layer away from the first electrode layer 51 to form a second film layer. Since the two film layers are made of different materials, there is a certain interface between the two film layers.

[0056] Of course, the multiple materials can also include a third material. Based on the formation of the first film layer, a second film layer is formed on the side of the first film layer facing away from the first electrode layer 51. Then, the second film layer, the first film layer, and the photoelectric conversion component 52 are jointly etched to form a second hollow portion P2. Then, a third film layer is formed using a third material on the side of the second film layer facing away from the first electrode layer 51, in the second hollow portion P2 and on the side of the second film layer facing away from the first electrode layer 51. Alternatively, based on the formation of the first film layer, the first film layer and the photoelectric conversion component 52 are etched to form a second hollow portion P2. Then, a second film layer is formed within the second hollow portion P2 and on the side of the first film layer facing away from the first electrode layer 51. Then, a third film layer is formed on the side of the second film layer facing away from the first electrode layer 51. The multiple materials can also include more materials, or a combination of multiple materials can be used when forming one of the film layers.

[0057] In the above examples, at least one film layer is formed before etching the second hollow portion P2. This film layer can provide protection for the photoelectric conversion component 52. Under the protection of the film layer, etching the second hollow portion P2 can reduce the risk of external water vapor and oxygen intruding into the photoelectric conversion component 52, thereby ensuring the stable performance of the solar cell 5.

[0058] The scribing can be done by laser scribing, masking or exposure. Taking laser scribing as an example, a laser beam is emitted to the surface of the film layer. The laser energy contained in the laser beam will be transferred to the film layer. The pre-formed film layer has good thermal conductivity, and heat can be conducted evenly and quickly during the scribing process. The edge structure of the second hollow part P2 formed by scribing is relatively regular.

[0059] The portion of the photoelectric conversion component 52 that faces away from the first electrode layer 51 constitutes the main body 531 of the second electrode layer 53, while the portion located within the second cutout portion P2 constitutes the connecting portion 532 of the second electrode layer 53. The main body 531 includes at least two film layers, and the connecting portion 532 contains fewer film layers than the main body 531. The portion of the main body 531 can provide pre-protection during the scribing process of the sub-cell 6. The difference in the number of film layers between the main body 531 and the connecting portion 532 is macroscopically manifested as the thickness of the main body 531 being greater than the thickness of the connecting portion 532. Figure 4 In the diagram, H1 represents the thickness of the main body 531, H2 represents the thickness of the connecting part 532, and X represents the thickness direction of the sub-cell.

[0060] Therefore, in the embodiment of this application, when forming the structure of the sub-cell 6, by setting the thickness of the main body 531 to be greater than the thickness of the connecting part 532, on the one hand, the main body 531 can protect the photoelectric conversion component 52, reduce the risk of external water vapor and oxygen intruding into the photoelectric conversion component 52, and ensure the stable performance of the photoelectric conversion component 52, thereby ensuring the photoelectric conversion efficiency of the solar cell 5; on the other hand, when the second hollow part P2 is etched, part of the main body 531 can play a good role in heat conduction, the heat island at the edge of the structure of the second hollow part P2 formed by etching is smaller, the structure of the sub-cell 6 is more stable, and the photoelectric conversion efficiency of the solar cell 5 can be improved.

[0061] In some embodiments, the ratio of the thickness of the main body 531 to the thickness of the connecting portion 532 is A, where 1 < A ≤ 20.

[0062] When A equals 1, the main body and the connecting part are integrally formed, which means that the second electrode layer includes a film layer. During the scribing process, the second hollow part needs to be scribed first, and then the second electrode layer needs to be formed. The main body will not be able to provide protection for the photoelectric conversion component.

[0063] When A is greater than 20, the thickness of the main body is much greater than the thickness of the connecting part. In this case, the thickness of the main body accounts for a large proportion of the overall thickness of the sub-cell, especially the thickness of the photoelectric conversion component, which is relatively small. The photoelectric conversion component absorbs light relatively little, thereby reducing the amount of photocurrent that the sub-cell can convert and output, and leading to a decrease in the photoelectric conversion efficiency of the solar cell.

[0064] In this embodiment, the ratio of the thickness of the main body 531 to the thickness of the connecting part 532 satisfies 1 < A ≤ 20; the upper limit of A can be selected from 3, 4, 5, 6, 7, 8, 9, 10, 15 or 20, and the lower limit of A can be selected from 2, 3, 4, 5, 6, 7, 8, 9, 10 or 15. The range of A can be selected from any reasonable combination of the above upper and lower limits, for example, 1 < A ≤ 10. When A satisfies the above range, the main body 531 can not only provide good protection for the photoelectric conversion component 52, but also improve the photoelectric conversion efficiency of the solar cell 5.

[0065] The main body 531 can be made of one or more materials. The materials of the main body 531 will be described below.

[0066] In some embodiments, the main body 531 is made of the same material. With the thickness of the main body 531 greater than the thickness of the connecting portion 532, the main body 531 includes at least two film layers, each made of the same material. The two film layers are substantially interface-free; in other words, the interior of the main body 531 is substantially interface-free, which improves the overall structural stability of the main body 531. Exemplarily, the material of the main body 531 includes gold (Au), silver (Ag), copper (Cu), aluminum (Al), transparent conductive oxide (TCO), or carbon. TCO includes fluorine-doped tin oxide (FTO, SnO2:F), indium tin oxide (ITO, In2O3:Sn), aluminum-doped zinc oxide (AZO, ZnO:Al), or antimony-doped tin oxide (ATO, Sn2O:Sb). The abbreviation SnO2:F is used as an example, where SnO2:F represents tin oxide (SnO2) doped with fluorine (F).

[0067] Of course, each film layer can be made of a mixture of materials, with each film layer having essentially the same material and virtually no interfaces between them, resulting in a relatively stable structure for the main body 531. For example, the material of the main body 531 may include at least two of gold (Au), silver (Ag), copper (Cu), and aluminum (Al).

[0068] In other embodiments, the main body 531 is made of multiple materials. With the thickness of the main body 531 greater than the thickness of the connecting portion 532, the main body 531 includes at least two film layers, each of which can be made of a different material. For example, the film layer pre-formed on the photoelectric conversion component 52 uses a first material, and the surface film layer formed on this film layer facing away from the first electrode layer 51 uses a second material. The first material can be selected from materials with relatively good thermal conductivity, which is beneficial for heat conduction during the scribing process; the second material can be selected from materials with relatively good thermal conductivity, which is beneficial for improving electron transport efficiency. In other words, the main body 531 is made of multiple materials, which is beneficial for comprehensively improving the performance of the solar cell 5. Exemplarily, the material of each film layer in the main body 531 can be independently selected from materials including gold (Au), silver (Ag), copper (Cu), aluminum (Al), transparent conductive oxide (TCO), or carbon.

[0069] like Figure 5As shown, based on the use of different materials for each film layer in the main body 531, the main body 531 includes a first part 5311 and a second part 5312. The second part 5312 is located on the side of the first part 5311 facing away from the first electrode layer 51, and the first part 5311 and the second part 5312 are made of different materials. For example, the first part 5311 and the second part 5312 can be independently selected from materials including gold (Au), silver (Ag), copper (Cu), aluminum (Al), transparent conductive oxide (TCO), or carbon. The first part 5311 can provide good protection for the photoelectric conversion component 52 and can also play a good role in thermal conduction during the scribing process; the second part 5312 can play a good role in electrical conductivity, which is beneficial to electron transport.

[0070] like Figure 6 In some embodiments, the sub-cell 6 includes a barrier layer 54 for blocking the transport of a first charge. The barrier layer 54 is disposed on the side of the photoelectric conversion component 52 opposite to the first electrode layer 51. Exemplarily, the first charge can be a hole, and correspondingly, the second charge mentioned below is an electron. The barrier layer 54 can block the transport of holes at the interface of the photoelectric conversion component 52, thereby improving the transport efficiency of electrons from the photoelectric conversion component 52 to the second electrode layer 53, and reducing the risk of recombination of electrons and holes at the interface of the photoelectric conversion component 52, further improving the electron transport efficiency, thereby improving the photoelectric conversion efficiency of the solar cell 5.

[0071] Optionally, the barrier layer 54 may be made of at least one of block copolymer (BCP), lithium fluoride (LiF), and tin oxide (SnO2). Taking BCP as an example, BCP can fully fill the grain boundaries on the surface of the photoelectric conversion component 52, thereby reducing the number of holes accumulating at the interface and suppressing electron-hole recombination at the interface.

[0072] When carving the second hollow section, it is necessary to carve after the barrier layer is formed. This will result in the barrier layer being exposed for a relatively long time, and the barrier layer is more susceptible to the intrusion of external moisture and oxygen.

[0073] like Figure 7 As shown, in order to ensure the performance of the solar cell 5, in this embodiment, a barrier layer 54 is located between the photoelectric conversion component 52 and the main body 531. The main body 531 can protect the barrier layer 54, reducing the risk of external moisture and oxygen intruding into the barrier layer 54, thereby ensuring the performance of the solar cell 5. Specifically, the main body 531 includes at least two film layers. Before performing the second scribing, at least one film layer is pre-formed on the barrier layer 54, and the second scribing is performed under the protection of this film layer to form the second cutout P2.

[0074] Optionally, the weight ratio of the barrier layer 54 to the weight of the main body 531 is B, where 0.001≤B≤0.2; or, alternatively, 0.005≤B≤0.1.

[0075] If the weight of the barrier layer 54 is too large, its thickness will be relatively large, and the thickness of the barrier layer 54 will account for a large proportion of the overall thickness of the sub-cell 6. This may result in a relatively small proportion of the thickness of the photoelectric conversion component 52 of the sub-cell 6, thereby reducing the photoelectric conversion efficiency. If the weight of the barrier layer 54 is too small, its thickness will be relatively small, and the barrier layer 54 may not be able to effectively block holes. Figure 7 In the diagram, H1 represents the thickness of the main body and H3 represents the thickness of the barrier layer 54.

[0076] B satisfies 0.001≤B≤0.2, and optionally 0.005≤B≤0.1. On the basis of the barrier layer having a good hole blocking effect, the main body 531 can also play a good protective role for the barrier layer 54, thereby improving the photoelectric conversion efficiency of the solar cell 5.

[0077] Optionally, the ratio of the thickness of the barrier layer 54 to the thickness of the main body 531 is C, where 0.005≤C≤0.2; or, alternatively, 0.01≤C≤0.1.

[0078] If the thickness of the barrier layer 54 is too thick, its thickness accounts for a large proportion of the overall thickness of the sub-cell 6. This may result in a relatively small proportion of the thickness of the photoelectric conversion component 52 in the sub-cell 6, thereby reducing the photoelectric conversion efficiency. If the thickness of the barrier layer 54 is relatively small, it may not be able to effectively block holes.

[0079] C satisfies 0.005≤C≤0.2; optionally, 0.01≤C≤0.1. On the basis of the barrier layer having a good hole blocking effect, the main body 531 can also play a good protective role for the barrier layer 54, thereby improving the photoelectric conversion efficiency of the solar cell 5.

[0080] like Figure 8 As shown, the photoelectric conversion module 52 is the core component of the solar cell 5. The structure of the photoelectric conversion module 52 will be described next.

[0081] In some embodiments, the photoelectric conversion component 52 includes a first charge transport layer 521, a photoelectric conversion layer 522, and a second charge transport layer 523 sequentially stacked along the thickness direction of the sub-cell 6. The first charge transport layer 521 is located between the first electrode layer 51 and the photoelectric conversion layer 522. The first charge transport layer 521 is a hole transport layer, and the second charge transport layer 523 is an electron transport layer. The solar cell 5 includes a substrate 50, a first electrode layer 51, a first charge transport layer 521, a photoelectric conversion layer 522, a second charge transport layer 523, and a second electrode layer 53 sequentially arranged along its own thickness direction X.

[0082] The first charge transport layer 521 is made of at least one of the following materials: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]PTAA, polymer PEDOT (3,4-ethylenedioxythiophene monomer), nickel oxide NiOx, CuI, and Cu2O. The first charge transport layer 521 is disposed between the first electrode layer 51 and the photoelectric conversion layer 522, enabling the formation of good ohmic contact, effective hole transport, reduced carrier recombination at the interface, and improved photoelectric conversion efficiency.

[0083] The photoelectric conversion layer 522 is made of an ABX3 crystal structure, which is the crystal structure of an organic-inorganic hybrid perovskite material, exhibiting a cubic or octahedral structure. Specifically, A includes at least one of methylammonium (MA), formamide (FA), and cesium (Cs); B includes at least one of lead (Pb), tin (Sn), and copper (Cu); and X includes at least one of bromine (Br), chlorine (Cl), and iodine (I). The photoelectric conversion layer 522 can absorb photons and convert them into electrons and holes, which are then transported to the first charge transport layer 521 and the second charge transport layer 523 under the influence of a built-in electric field.

[0084] The material of the second charge transport layer 523 includes at least one of C60, tin oxide (SnO2), fullerene derivative PCBM, and titanium oxide (TiO2). The second charge transport layer 523 is disposed between the photoelectric conversion layer 522 and the second electrode layer 53. On the one hand, this reduces the energy level barrier between the photoelectric conversion layer 522 and the second electrode layer 53, which is beneficial for electron transport and improves electron transport efficiency. On the other hand, the second charge transport layer 523 itself facilitates electron transport, blocks holes, and reduces the risk of carrier recombination at the interface.

[0085] In some embodiments, the material of the first electrode layer 51 includes gold (Au), silver (Ag), copper (Cu), aluminum (Al), transparent conductive oxide (TCO), or carbon. Gold (Au), silver (Ag), copper (Cu), and aluminum (Al) are metal electrodes, which have good conductivity. Transparent conductive oxide (TCO) is used as a transparent electrode, and the transparent electrode includes fluorine-doped tin oxide (FTO), indium tin oxide (ITO), or aluminum-doped zinc oxide (AZO). The first electrode layer 51 using the above materials has good conductivity, which is beneficial for hole transport.

[0086] like Figure 8 and Figure 9 As shown in the embodiments of this application, a method for preparing a solar cell is also provided, the method comprising: S100 provides a substrate.

[0087] S200, a bottom electrode is formed on one side of the substrate. The bottom electrode includes a plurality of first electrode layers spaced apart to divide the solar cell into a plurality of sub-cells.

[0088] A bottom electrode, such as a transparent glass electrode, is formed on the surface of the substrate 50 by magnetron sputtering or chemical means. The bottom electrode can be divided into multiple first electrode layers 51 by scribing. The gap between the multiple first electrode layers 51 is a first hollow portion P1. The scribing method can include laser scribing, masking or exposure.

[0089] S300, photoelectric conversion components are formed on the surfaces of multiple first electrode layers that are away from the substrate.

[0090] The photoelectric conversion component 52 includes a first charge transport layer 521 (hole transport layer), a photoelectric conversion layer 522, and a second charge transport layer 523 (electron transport layer) stacked sequentially along its own thickness X direction.

[0091] A first charge transport layer 521 is formed on the surface of the first electrode layer 51 away from the substrate 50 by magnetron sputtering, chemical deposition, atomic layer deposition (ALD), or coating. The first cutout portion P1 can be filled with insulating material, or it can be directly set to the material of the first charge transport layer 521.

[0092] A photoelectric conversion layer 522 is formed on the surface of the first charge transport layer 521 away from the substrate by coating, spraying, spin coating, evaporation or chemical deposition.

[0093] A second charge transport layer 523 is formed on the surface of the photoelectric conversion layer 522 away from the substrate 50 by magnetron sputtering, chemical deposition, atomic layer deposition (ALD), or coating.

[0094] The etching is performed by laser scribing, masking or exposure to form a second hollow portion P2 that penetrates the first charge transport layer 521, the photoelectric conversion layer 522 and the second charge transport layer 523.

[0095] S400, a second electrode layer is formed on the surface of the photoelectric conversion component away from the substrate. The second electrode layer includes a main body and a connection portion electrically connected to the main body. The connection portion of one of the multiple sub-cells is used to electrically connect to the first electrode layer of another sub-cell, so that the multiple sub-cells are electrically connected. The thickness of the main body is greater than the thickness of the connection portion.

[0096] In the second hollow portion P2 and on the surface of the photoelectric conversion component 52 away from the substrate 50, a second electrode layer 53, such as a metal electrode, is formed by magnetron sputtering, chemical deposition, atomic layer deposition (ALD), or coating. The metal electrode located in the second hollow portion P2 enables the series connection of adjacent sub-cells 6.

[0097] The third hollow portion P3 is formed in the metal electrode, the first charge transport layer 521, the photoelectric conversion layer 522, and the second charge transport layer 523 by laser scribing, masking, or exposure.

[0098] The main body 531 of the second electrode layer 53 is located on the side of the photoelectric conversion component 52 away from the substrate 50, and the connecting portion 532 of the second electrode layer 53 is located in the second cutout portion P2. After the second electrode layer 53 is formed, the second electrode layer 53 and the photoelectric conversion component 52 are etched to form a third cutout portion P3, which penetrates the second electrode layer 53 and the photoelectric conversion component 52.

[0099] The solar cell prepared according to the preparation method of the present application has a main body thickness greater than the connecting part thickness, which can improve the photoelectric conversion efficiency of the solar cell.

[0100] like Figure 10 As shown, in some embodiments, step S400 includes: S410 forms a first portion on the surface of the photoelectric conversion component away from the substrate.

[0101] S420, along the thickness direction of the sub-cell, sequentially removes a portion of the first part and a portion of the photoelectric conversion component to form a hollow area.

[0102] The hollowed-out area in this step is the second hollowed-out section mentioned above.

[0103] S430, a second part is formed on the surface of the first part away from the substrate, and a connecting part is formed in the hollow area, wherein the second part and the first part are made of different materials.

[0104] The second part is made of a different material than the first part, and the resulting second electrode layer can simultaneously achieve both electrical conductivity and thermal conductivity, thus comprehensively improving the performance of the solar cell.

[0105] like Figure 11 As shown, in some embodiments, after step S300, the following steps are also included: S500 has a barrier layer between the photoelectric conversion component and the second electrode layer, which is used to block hole transmission.

[0106] Setting up a blocking layer can block hole transport, reduce the risk of recombination of holes and electrons at the interface of the photoelectric conversion component, and improve the photoelectric conversion efficiency of solar cells.

[0107] Based on the above steps, the positive and negative output electrodes can also be bonded with conductive tape, ultrasonically welded, laser welded, or welded with welding flux to form external output electrodes.

[0108] Example The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0109] Examples 1 to 12, Comparative Examples 1 to 2 Take a set of FTO conductive glass with a specification of 100mm×100mm, use an infrared laser (wavelength 1064nm) to etch the first hollow part P1, P1 is about 30um wide, and divide the whole glass into 10 sub-cells. The series resistance of different sub-cells is greater than 10MΩ. The top and bottom 10mm are used as the component welding area. After cleaning with cleaning agent (multiple actives and alkaline additives), it is ultrasonically vibrated in deionized water, ethanol and acetone for 10min in sequence. After ultrasonic treatment, it is dried with N2 for later use.

[0110] The cleaned FTO conductive glass is placed in a magnetron sputtering apparatus (with a certain amount of Ar:O2 introduced) to deposit a hole transport layer NiOx with a thickness of about 15nm.

[0111] Irradiate with ultraviolet light (wavelength 253.7 nm) for 10 min, then coat the surface of the hole transport layer away from the FTO conductive glass with a perovskite solution (FA). x Cs 1-x PbI y Br 3-y The perovskite absorber layer was crystallized into a film (VCD, annealed at 120°C for 20 min), and then removed for later use.

[0112] The component forming the perovskite absorber layer is placed in a vacuum thermal evaporation equipment, and a vacuum of 4×10⁻⁶ is applied. -4 Pa, a 30 nm C60 electron transport layer is sequentially deposited on the surface of the perovskite absorber layer opposite to the FTO conductive glass.

[0113] A barrier layer (thermally evaporated BCP, 6 nm thick) is formed on the surface of the electron transport layer away from the FTO conductive glass. The material, weight and thickness of the barrier layer are shown in Table 1.

[0114] A first part is formed on the surface of the barrier layer away from the FTO conductive glass. The material, weight and thickness of the first part are shown in Table 1.

[0115] The above components are cooled to about 30°C, the vacuum is broken and the second cutout P2 is laser-etched. The width of P2 is 150um and it is etched onto the surface of the FTO conductive glass. The interval between P2 and P1 is 20um.

[0116] The component is placed back into the vacuum thermal evaporation equipment to deposit and form a second part. The material, weight and thickness of the second part are shown in Table 1.

[0117] The temperature was lowered to about 30°C, and the vacuum was broken to remove the third cutout part P3 etched by the P-second green laser. The width of P3 is 15um, and it is etched into the FTO conductive glass. The interval between P3 and P2 is 20um.

[0118] Then, infrared edge cleaning (wavelength 1064nm) is used on the module, that is, 10mm is etched on each side of the module to obtain the solar cell.

[0119] Performance testing 1. Testing of photoelectric conversion efficiency At 25℃, 1000W / m 2 In the solar simulator (3A standard), input the effective area of ​​the solar cell as 64cm². 2 The energy conversion efficiency of the solar cell was tested using a test voltage of -2 to 14V and a scan rate (320 scan points).

[0120] 2. Thickness test of Part 1 and Part 2 Use a glass cutter to make a cut along the direction parallel to the incident light on the back of the solar cell, break the solar cell off, and take 10 points on the cross-section containing P2. Use a scanning electron microscope to photograph the thickness of the bottom (second part) and edge (first part) of P2 at 30,000x or 50,000x magnification.

[0121] 3. Detachment thickness test Remove the electrodes using tape and use topological offset testing to measure the thickness.

[0122] The parameters and solar cell performance of Examples 1-12 and Comparative Examples 1-2 are shown in Table 1.

[0123] Table 1

[0124] As shown in Table 1, Comparative Example 1 does not include the second part, meaning that the photoelectric conversion component is basically unprotected during the second scribing process, and its photoelectric conversion efficiency is relatively poor.

[0125] Compared with Comparative Example 1, the photoelectric conversion efficiency of the solar cells in Examples 1 to 12 was significantly improved.

[0126] In Comparative Example 2, the thickness of the main body is relatively large, resulting in a smaller thickness of the photoelectric conversion module and a lower photoelectric conversion efficiency of the solar cell.

[0127] Compared to Comparative Example 2, the thickness of the main body in Examples 1 to 5 is moderate. In particular, when the ratio A of the thickness of the main body and the connecting part satisfies 1 < A ≤ 20, and especially when 1 < A ≤ 10, the photoelectric conversion efficiency of the solar cell is relatively excellent, and the photoelectric conversion efficiency of Example 1 is particularly excellent.

[0128] In Examples 6 to 12, the range of the thickness ratio C between the barrier layer and the main body was adjusted, thereby adjusting the photoelectric conversion efficiency of the solar cell. When C satisfies 0.005≤C≤0.2, especially when 0.01≤C≤0.1, the photoelectric conversion efficiency of the solar cell is relatively excellent.

[0129] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A solar cell having a plurality of sub-cells, each of the sub-cells comprising a first electrode layer, a photoelectric conversion component, and a second electrode layer sequentially stacked along its own thickness direction, the second electrode layer comprising a main body portion and a connecting portion electrically connected to the main body portion, wherein the connecting portion of one of the plurality of sub-cells is used to electrically connect to the first electrode layer of another sub-cell, thereby electrically connecting the plurality of sub-cells. in, The thickness of the main body is greater than the thickness of the connecting part. The sub-cell includes a blocking layer for blocking the first charge transport, the blocking layer being disposed between the photoelectric conversion component and the main body; The ratio of the thickness of the barrier layer to the thickness of the main body is C, where 0.00056 ≤ C ≤ 0.

333.

2. The solar cell according to claim 1, wherein, The ratio of the thickness of the main body to the thickness of the connecting part is A, where 1 < A ≤ 20.

3. The solar cell according to claim 2, wherein, The ratio A of the thickness of the main body to the thickness of the connecting part satisfies 1 < A ≤ 10.

4. The solar cell according to any one of claims 1-3, wherein, The main body is made of the same material.

5. The solar cell according to claim 4, wherein, The main body is made of materials including gold (Au), silver (Ag), copper (Cu), aluminum (Al), transparent conductive oxide (TCO), or carbon.

6. The solar cell according to any one of claims 1-3, wherein, The main body includes a first part and a second part, the second part being located on the side of the first part opposite to the first electrode layer, and the first part and the second part being made of different materials.

7. The solar cell according to claim 6, wherein, The materials of the first part and the second part are each independently selected from gold (Au), silver (Ag), copper (Cu), aluminum (Al), transparent conductive oxide (TCO), or carbon.

8. The solar cell according to any one of claims 1-3, wherein, The barrier layer is made of at least one of block copolymer BCP, lithium fluoride LiF, and tin oxide SnO2.

9. The solar cell according to claim 1, wherein, The ratio of the weight of the barrier layer to the weight of the main body is B, where 0.001 ≤ B ≤ 0.

2.

10. The solar cell according to claim 9, wherein, The ratio B of the weight of the barrier layer to the weight of the main body satisfies 0.005≤B≤0.

1.

11. The solar cell according to claim 1, wherein, The ratio C of the thickness of the barrier layer to the thickness of the main body satisfies 0.00056 ≤C≤0.

1.

12. The solar cell according to any one of claims 1-3, wherein, The photoelectric conversion component includes a first charge transport layer, a photoelectric conversion layer and a second charge transport layer stacked sequentially along the thickness direction of the sub-cell, wherein the first charge transport layer is located between the first electrode layer and the photoelectric conversion layer; The first charge transport layer is made of at least one of the following materials: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]PTAA, polymer PEDOT (3,4-ethylenedioxythiophene monomer), nickel oxide NiOx, CuI, and Cu2O; and / or The photoelectric conversion layer is made of an ABX3 crystal structure, wherein A includes at least one of methylammonium (MA), formamide (FA), and cesium (Cs); B includes at least one of lead (Pb), tin (Sn), and copper (Cu); and X includes at least one of bromine (Br), chloride (Cl), and iodine (I); and / or The material of the second charge transport layer includes at least one of C60, tin oxide SnO2, fullerene derivative PCBM, and titanium oxide TiO2.

13. The solar cell according to any one of claims 1-3, wherein, The material of the first electrode layer includes gold (Au), silver (Ag), copper (Cu), aluminum (Al), transparent conductive oxide (TCO), or carbon.

14. A photovoltaic module comprising a plurality of solar cells as described in any one of claims 1 to 13.

15. An electrical device comprising a photovoltaic module as claimed in claim 14, the photovoltaic module being used to provide electrical energy.

16. A method for preparing a solar cell, the method comprising: Provide substrate; A bottom electrode is formed on one side of the substrate, the bottom electrode comprising a plurality of first electrode layers spaced apart, to divide the solar cell into a plurality of sub-cells; Photoelectric conversion components are formed on the surfaces of multiple first electrode layers that are away from the substrate; A second electrode layer is formed on the surface of the photoelectric conversion component facing away from the substrate. The second electrode layer includes a main body and a connection portion electrically connected to the main body. The connection portion of one of the multiple sub-cells is used to electrically connect to the first electrode layer of another sub-cell, so that the multiple sub-cells are electrically connected. The thickness of the main body is greater than the thickness of the connection portion. The sub-cell includes a blocking layer for blocking first charge transport. The blocking layer is disposed between the photoelectric conversion component and the main body. The method includes providing a blocking layer between the photoelectric conversion component and the second electrode layer, the blocking layer being used to block hole transmission, and the ratio of the thickness of the blocking layer to the thickness of the main body being C, where 0.00056≤C≤0.

333.

17. The method for preparing a solar cell according to claim 16, wherein, The step of forming a second electrode layer on the surface of the photoelectric conversion component facing away from the substrate includes: A first portion is formed on the surface of the photoelectric conversion component that is away from the substrate; The first part and a portion of the photoelectric conversion component are removed sequentially along the thickness direction of the sub-cell to form a hollow area; A second portion is formed on the surface of the first portion that is away from the substrate, and a connecting portion is formed in the cutout area, wherein the second portion and the first portion are made of different materials.

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