Laminated solar cell, preparation method thereof and photovoltaic module
By introducing a gate line contact layer into the stacked solar cell, using transparent conductive thin film material and magnetron sputtering process, the high contact resistance problem between the metal gate line and the transparent conductive layer is solved, and the efficiency and stability of the battery are improved.
Patent Information
- Application Number
- CN202510577056.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-06
- Publication Date
- 2025-07-11
AI Technical Summary
In existing stacked solar cells, the contact resistance between the metal gate line and the transparent conductive layer is high, which limits the improvement of battery efficiency and stability, especially the poor interface contact performance of ultra-low-temperature slurry at low curing temperatures.
The gate line contact layer is introduced at the connection between the metal gate line and the transparent conductive layer, and a continuous or patterned transparent conductive film is used, and the materials include ITO, IZO, IWO, etc. are formed by magnetron sputtering process, with a thickness of 5-100 nm, enhancing the interface carrier concentration and contact area.
It effectively reduces the contact resistance between the metal gate line and the transparent conductive layer, improves the filling factor and photoelectric conversion efficiency of the stacked solar cells, improves the current distribution and thermal stability, and improves the overall efficiency and stability.
Smart Images
Figure CN120302801A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of solar cells, and specifically provides a tandem solar cell, a preparation method thereof, and a photovoltaic module. Background Art
[0002] The perovskite / crystalline silicon tandem solar cell is a high-efficiency photovoltaic device that vertically stacks a perovskite cell and a crystalline silicon cell to achieve a multi-junction structure, which can significantly improve the photoelectric conversion efficiency of solar energy. In recent years, with the substantial improvement in the efficiency of perovskite materials, the photoelectric conversion efficiency of this type of tandem cell has exceeded 34%, far higher than the efficiency limit of traditional crystalline silicon single-junction cells (about 27%), and has become an important development direction of the new generation of photovoltaic technology.
[0003] However, currently, due to the limitation of the perovskite cell on the curing temperature, it is necessary to use ultra-low temperature paste for curing below 130°C, which results in a relatively high contact resistance between the metal grid line and the transparent conductive layer in the tandem cell, thereby affecting the resistance and overall conversion efficiency of the cell.
[0004] Such a high contact resistance problem is an important bottleneck restricting the further improvement of the efficiency and industrialization promotion of tandem solar cells. Therefore, how to reduce the contact resistance between the metal grid line and the transparent conductive layer at a low curing temperature and improve the efficiency and stability of the tandem solar cell has become an urgent technical problem to be solved.
[0005] Correspondingly, there is a need in the art for a new tandem solar cell solution to solve the above problems. Summary of the Invention
[0006] In order to overcome the above defects, the present application is proposed to provide a tandem solar cell, a preparation method thereof, and a photovoltaic module to solve or at least partially solve the technical problem of how to reduce the contact resistance between the metal grid line and the transparent conductive layer at a low curing temperature and improve the efficiency and stability of the tandem solar cell.
[0007] In a first aspect, the present application provides a tandem solar cell, including a bottom cell and a perovskite top cell, the perovskite top cell having a transparent conductive layer and a metal grid line disposed on the transparent conductive layer, wherein,
[0008] the tandem solar cell further includes a grid line contact layer that at least covers the connection portion between the metal grid line and the transparent conductive layer.
[0009] In a technical solution of the above tandem solar cell, the grid line contact layer is a continuous transparent conductive thin film that covers the top and side walls of the metal grid line and the surface of the transparent conductive layer away from the bottom cell.
[0010] In one technical solution of the above-mentioned tandem solar cell, the grid contact layer is a patterned transparent conductive thin film, covering the top and side walls of the metal grid line and exposing the surface of the transparent conductive layer away from the bottom cell.
[0011] In one technical solution of the above-mentioned tandem solar cell, the carrier concentration of the grid contact layer is between 1E 19 -1E 21 / cm 3 and the thickness is 5 - 100 nm.
[0012] In one technical solution of the above-mentioned tandem solar cell, the grid contact layer is formed by a magnetron sputtering process.
[0013] In one technical solution of the above-mentioned tandem solar cell, the grid contact layer is a single-layer transparent conductive thin film or a stack of multiple transparent conductive thin films.
[0014] In one technical solution of the above-mentioned tandem solar cell, the material of the grid contact layer includes at least one of ITO, IZO, IWO, and ICO.
[0015] In one technical solution of the above-mentioned tandem solar cell, the thickness of the transparent conductive layer is 5 - 100 nm.
[0016] In one technical solution of the above-mentioned tandem solar cell, the metal grid line is formed by at least one of screen printing, electrospraying, inkjet printing, and laser transfer printing.
[0017] In a second aspect, the present application provides a method for manufacturing a tandem solar cell for manufacturing the tandem solar cell according to any one of the above technical solutions. The tandem solar cell includes a bottom cell and a perovskite top cell. After forming a transparent conductive layer and a metal grid line provided on the transparent conductive layer in the perovskite top cell, it includes:
[0018] Forming a grid contact layer to at least cover the connection between the metal grid line and the transparent conductive layer.
[0019] In a third aspect, the present application provides a photovoltaic module, and the photovoltaic module includes the tandem solar cell according to any one of the above technical solutions.
[0020] One or more of the above technical solutions of the present application have at least one or more of the following beneficial effects:
[0021] In implementing the technical solution of the present application, the contact resistance between the metal grid line and the transparent conductive layer is effectively reduced, which is beneficial to improving the fill factor and photoelectric conversion efficiency of the tandem solar cell, and at the same time improving the current distribution and thermal stability of the device, thereby overall enhancing the efficiency and stability of the tandem solar cell. Description of the Drawings
[0022] Referring to the accompanying drawings, the disclosure of the present application will become more understandable. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the protection scope of the present application. In addition, similar numbers in the figures are used to represent similar components, where:
[0023] Figure 1 is a schematic diagram of a tandem solar cell according to an embodiment of the present application;
[0024] Figure 2 is a schematic diagram of a grid line contact layer according to an embodiment of the present application;
[0025] Figure 3 is a schematic diagram of a grid line contact layer according to another embodiment of the present application;
[0026] Figure 4 is a main step flow chart of a preparation method of a tandem solar cell according to an embodiment of the present application. Detailed Embodiments
[0027] Some embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principle of the present application and are not intended to limit the protection scope of the present application.
[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present application without creative efforts shall fall within the protection scope of the present application.
[0029] Unless otherwise defined, technical terms or scientific terms used in this application shall have the ordinary meanings understood by those of ordinary skill in the art to which this application pertains. The terms "first", "second" and similar words used in this application do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.
[0030] In a tandem solar cell, the metallization process is a key step in the preparation of metal grid lines. Especially in a tandem cell with a two-terminal structure, the metal grid lines of the perovskite top cell are usually formed on its transparent conductive oxide (TCO) layer by means of screen printing or thermal evaporation, etc., to facilitate charge extraction and transport. However, due to the poor thermal stability of perovskite materials, the top cell is extremely sensitive to the temperature of subsequent processes, and usually requires the subsequent process temperature to be lower than 130 °C. Therefore, the metallization paste used needs to have ultra-low temperature curing performance.
[0031] However, currently, ultra-low temperature pastes are not yet fully mature, the formulation development is difficult, the market supply is scarce, and the interfacial contact performance between them and the TCO is poor, often resulting in a relatively high contact resistance of the metal grid lines, thereby affecting the series resistance and overall conversion efficiency of the cell.
[0032] To solve the above problems, this application provides a tandem solar cell.
[0033] Figure 1 It is a schematic diagram of a tandem solar cell according to an embodiment of this application.
[0034] As Figure 1 shown, the tandem solar cell 10 includes a bottom cell 11 and a perovskite top cell 12, and the perovskite top cell 12 has a transparent conductive layer 113 and metal grid lines 114 disposed on the transparent conductive layer 113.
[0035] Wherein, the tandem solar cell 10 further includes a grid line contact layer 115, and the grid line contact layer 115 covers at least the connection between the metal grid lines 114 and the transparent conductive layer 113.
[0036] Specifically, the bottom cell 11 is a crystalline silicon bottom cell, including but not limited to PERC cells (Passivated Emitter and Rear Cell), HJT cells (Heterojunction Solar Cell), TOPCon cells (Tunnel Oxide Passivated Contact Cell), and IBC cells (Interdigitated Back Contact Cell). The bottom cell 11 sequentially includes a first metal electrode 116, a first transparent conductive layer 107, a first doped amorphous silicon layer 104, a first intrinsic amorphous silicon layer 103, an n-type crystalline silicon layer 101, a second intrinsic amorphous silicon layer 102, a second doped amorphous silicon layer 105, and a third doped amorphous silicon layer 106 from bottom to top.
[0037] The above-mentioned first doped amorphous silicon layer 104, second doped amorphous silicon layer 105, and third doped amorphous silicon layer 106 can also be doped microcrystalline silicon layers or doped nanocrystalline silicon layers.
[0038] Optionally, when the first doped amorphous silicon layer 104 is n-type, the second doped amorphous silicon layer 105 is p-type; when the first doped amorphous silicon layer 104 is p-type, the second doped amorphous silicon layer 105 is n-type.
[0039] Furthermore, a tunneling layer 108 is provided between the bottom cell 11 and the perovskite top cell 12.
[0040] The perovskite top cell 12 sequentially includes a hole transport layer 109, a perovskite layer 110, a first electron transport layer 111, a second electron transport layer 112, a transparent conductive layer 113, and a metal grid line 114 from bottom to top.
[0041] Among them, the perovskite material used in the perovskite layer 110 is generally a three-dimensional structure ABX3, where A is a monovalent cation, including but not limited to one or several monovalent cation mixtures of cesium (Cs), rubidium (Rb), methylammonium (CH3NH3), formamidinium (CH2(NH2)2); B is a divalent cation, including but not limited to one or several divalent cation mixtures of lead (Pb), copper (Cu), zinc (Zn), gallium (Ga), tin (Sn), calcium (Ca); X is a monovalent anion, including but not limited to one or several monovalent anion mixtures of iodine (I), bromine (Br), chlorine (Cl), fluorine (F), and thiocyanate ion (SCN).
[0042] Since the first metal electrode 116, also known as the back metal electrode, is provided in the bottom cell 11, the metal grid line 114 is also known as the second metal electrode or the front metal electrode. Optionally, the metal grid line 114 is formed by at least one of screen printing, electrospraying, inkjet printing, and laser transfer. The material of the metal grid line 114 can be silver, copper, aluminum, or silver-coated copper, silver-coated aluminum, etc.
[0043] Since the bottom cell 11 is provided with a first transparent conductive layer 107, also known as the first TCO layer; thus, the transparent conductive layer 113 is also known as the second transparent conductive layer or the second TCO layer. Preferably, the thickness of the transparent conductive layer 113 is 5-100 nm.
[0044] Those skilled in the art can understand that the above bottom cell 11 and perovskite top cell 12 are not limited to the above stacked structure. For example, the first electron transport layer 111 and the second electron transport layer 112 can be combined into one electron transport layer, or the stacked cell can be changed from two-terminal to four-terminal, etc., as long as the function of the stacked solar cell can be satisfied.
[0045] Furthermore, in one embodiment, a specific structure of the grid line contact layer 115 is shown in Figure 2 . Figure 2 It is a schematic diagram of the grid line contact layer according to an embodiment of the present application.
[0046] Among them, the grid line contact layer 115 is a continuous transparent conductive film, covering the top and side walls of the metal grid line 114 and the surface of the transparent conductive layer 113 away from the bottom cell.
[0047] Optionally, the material of the grid line contact layer 115 includes at least one of ITO, IZO, IWO, and ICO to meet the light incident requirements of the perovskite top cell 12.
[0048] Since the material of the grid line contact layer 115 also belongs to the transparent conductive material, the grid line contact layer 115 is also known as the third transparent conductive layer or the third TCO layer.
[0049] The following is the contact resistivity verified by the TLM test (transmission length method test). Please refer to Table 1 below:
[0050] Table 1
[0051] Among them, the first group and the second group are the control groups without the grid line contact layer 115, and repeated experiments under the same conditions. Among them, polished-IZO is the transparent conductive layer 113.
[0052] The third group and the fourth group are the experimental groups with the grid line contact layer 115, and repeated experiments under the same conditions. Among them, polished-IZO is the transparent conductive layer 113, and IZO after the metal grid line is the grid line contact layer 115.
[0053] In this table, ρc is the resistivity, Rc is the total contact resistance, and Lt is the transfer length value.
[0054] By performing a paste contact resistance test on metal grid lines with the same preset line width, it is found that the resistivity drops significantly after setting the grid line contact layer 115. It can be seen that the added grid line contact layer 115 in this embodiment can effectively reduce the contact resistivity between the ultra-low temperature paste and the transparent conductive layer 113.
[0055] In the tandem solar cell of this embodiment, the contact resistance between the metal grid line 114 and the transparent conductive layer 113 is effectively reduced, which is beneficial to improving the fill factor and photoelectric conversion efficiency of the tandem solar cell. At the same time, the current distribution and thermal stability of the device are improved, thereby overall enhancing the efficiency and stability of the tandem solar cell.
[0056] Further, as Figure 3 shown, in another embodiment of the present application, the grid line contact layer 115 is a patterned transparent conductive thin film that covers the top and side walls of the metal grid line 114 and exposes the surface of the transparent conductive layer 113 away from the bottom cell 11.
[0057] That is, the width of the patterned grid line contact layer 115 should be greater than or equal to the width of the metal grid line 114 to ensure that the transparent conductive thin film completely covers the metal grid line 114.
[0058] Optionally, those skilled in the art can use a patterned photoresist to prepare the grid line contact layer 115.
[0059] In this embodiment, not only the contact area of the grid line contact layer 115 is increased, but the exposed partial surface of the transparent conductive layer 113 can increase the light transmittance and further improve the efficiency of the tandem solar cell 10.
[0060] In the above technical solution, the carrier concentration of the grid line contact layer 115 is between 1E 19 -1E 21 / cm 3 and the thickness is 5 - 100 nm. Further, the first TCO layer and the second TCO layer can also meet the above conditions.
[0061] Preferably, the grid line contact layer 115 is formed by a magnetron sputtering process.
[0062] The grid line contact layer 115 in the above technical solution forms a dual contact path with the transparent conductive layer 113 at the bottom of the metal grid line 114, which can enhance the interfacial carrier transport ability to a certain extent, reduce the interfacial resistance, and thus improve the device performance and stability.
[0063] Moreover, since there is no need for additional pattern etching treatment after metallization, it meets the requirements of simplifying the process steps and reducing the preparation cost while maintaining a low contact resistance.
[0064] Further, above the grid line contact layer 115, an antireflection layer can be further prepared to reduce the reflection loss of incident light on the surface of the battery.
[0065] Optionally, the grid line contact layer 115 is a single-layer transparent conductive thin film or a stack of multiple transparent conductive thin films. When using a stack of multiple transparent conductive thin films as the grid line contact layer 115, by designing the thickness of different transparent conductive thin films, the effect of assisting antireflection or replacing the traditional antireflection layer can be achieved.
[0066] On the other hand, the present application provides a method for manufacturing a stacked solar cell for manufacturing the stacked solar cell according to any one of the above technical solutions.
[0067] Among them, the stacked solar cell 10 includes a bottom cell 11 and a perovskite top cell 12. After forming the transparent conductive layer 113 on the perovskite top cell 12 and setting the metal grid line 114 on the transparent conductive layer 113, it includes: forming a grid line contact layer 115 to at least cover the connection between the metal grid line 114 and the transparent conductive layer 113.
[0068] In one embodiment, before forming the grid line contact layer 115, a method for manufacturing a perovskite / crystalline silicon stacked solar cell is provided. Please refer to Figure 1 .
[0069] Step S1: Provide a C-doped silicon substrate, that is, Figure 1 the n-type crystalline silicon layer 101 in 2 , with a resistivity of 2 Ω·cm
[0070] Step S2: Form an intrinsic amorphous silicon layer on the upper surface of the silicon substrate by plasma-enhanced chemical vapor deposition (PECVD), that is, Figure 1 the second intrinsic amorphous silicon layer 102 in
[0071] Step S3: Continue to deposit another intrinsic amorphous silicon layer on the lower surface of the silicon substrate by PECVD, that is, Figure 1 the first intrinsic amorphous silicon layer 103 in
[0072] Step S4: Deposit a p-type microcrystalline silicon layer on the first intrinsic amorphous silicon layer 103 by PECVD, that is, Figure 1 the first doped amorphous silicon layer 104 in
[0073] Step S5: Deposit an n-type microcrystalline silicon layer on the second intrinsic amorphous silicon layer 102 by PECVD, that is, Figure 1 the second doped amorphous silicon layer 105 in
[0074] Step S6, deposit another p-type microcrystalline silicon layer on the second doped microcrystalline silicon layer 105 by PECVD, namely Figure 1 the third doped amorphous silicon layer 106 in Figure 1 with a thickness of about 10 nm;
[0075] Step S7, deposit an ITO layer on the first doped amorphous silicon layer 104 by magnetron sputtering, namely Figure 1 the first transparent conductive layer 107 in Figure 1 with a thickness of about 80 nm;
[0076] Step S8, continue to deposit another ITO layer on the third doped amorphous silicon layer 106 by magnetron sputtering, namely Figure 1 the tunneling layer 108 in Figure 1 with a thickness of about 20 nm;
[0077] Step S9, form a NiO layer on the tunneling layer 108 by magnetron sputtering, namely Figure 1 the hole transport layer 109 in Figure 1 with a thickness of about 20 nm;
[0078] Step S10, form a perovskite active layer on the hole transport layer 109 by slot-die coating, namely Figure 1 the perovskite layer 110 in Figure 1 with a thickness of about 1000 nm;
[0079] Step S11, form a C60 layer on the perovskite active layer by thermal evaporation, namely Figure 1 the first electron transport layer 111 in Figure 1 with a thickness of about 30 nm;
[0080] Step S12, deposit an SnO2 layer on the C60 layer by atomic layer deposition (ALD) technology, namely Figure 1 the second electron transport layer 112 in Figure 1 with a thickness of about 20 nm;
[0081] Step S13, form an IZO layer on the SnO2 layer by magnetron sputtering, namely Figure 1 the transparent conductive layer 113 in Figure 1 with a thickness of about 100 nm;
[0082] Step S14, form a front metal silver grid line on the IZO layer by screen printing, namely Figure 1 the metal grid line 114 in Figure 1 ;
[0083] Step S15, form another IZO layer on the front metal silver grid line by magnetron sputtering, namely Figure 1 the grid line contact layer 115 in Figure 1 with a thickness of about 50 nm;
[0084] Step S16, finally, form a back metal silver electrode on the back of the cell by screen printing, namely Figure 1 the first metal electrode 116 in Figure 1 .
[0085] Further, reference may be made together to the attached Figure 4 , Figure 4 which is a main step flowchart of a method for manufacturing a tandem solar cell according to an embodiment of the present application.
[0086] As Figure 4 shown, the method for manufacturing a tandem solar cell in the embodiment of the present application mainly includes the following steps S41 - step S42.
[0087] Step S41, forming a transparent conductive layer 113 on the perovskite top cell 12 and a metal grid line 114 disposed on the transparent conductive layer 113;
[0088] Step S42, forming a grid contact layer 115 to at least cover the connection between the metal grid line 114 and the transparent conductive layer 113.
[0089] It should be noted that although the above embodiments describe the various steps in a specific order, those skilled in the art can understand that in order to achieve the effects of the present application, the different steps do not necessarily have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders, and these variations are all within the protection scope of the present application.
[0090] On the other hand, the present application also provides a photovoltaic module, and the photovoltaic module includes the tandem solar cell described in any one of the above technical solutions.
[0091] It can be understood that since this photovoltaic module has substantially the same technical effects as the aforementioned tandem solar cell, for the sake of brevity, the technical effects of this photovoltaic module will not be described again here.
[0092] All of the above optional technical solutions can be combined arbitrarily to form optional embodiments of the present application, and will not be elaborated one by one here.
[0093] In the above embodiments, the descriptions of the various embodiments have their own emphases. For parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.
[0094] So far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principle of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present application.
Claims
1. A stacked solar cell (10), characterized in that, Comprising a bottom cell (11) and a perovskite top cell (12), the perovskite top cell (12) having a transparent conductive layer (113) and metal grid lines (114) disposed on the transparent conductive layer (113), wherein, The tandem solar cell (10) further includes a grid line contact layer (115) that at least covers the connection between the metal grid lines (114) and the transparent conductive layer (113).
2. The laminated solar cell according to claim 1, wherein The grid line contact layer (115) is a continuous transparent conductive thin film that covers the top and side walls of the metal grid lines (114) and the surface of the transparent conductive layer (113) away from the bottom cell (11).
3. The laminated solar cell according to claim 1, wherein The grid line contact layer (115) is a patterned transparent conductive thin film that covers the top and side walls of the metal grid lines (114) and exposes the surface of the transparent conductive layer (113) away from the bottom cell (11).
4. The stacked solar cell according to claim 1, wherein The carrier concentration of the gate line contact layer (115) is between 1E 19 -1E 21 / cm 3 , and the thickness is 5 - 100 nm.
5. The laminated solar cell according to claim 1, characterized in that, The grid line contact layer (115) is formed by a magnetron sputtering process.
6. The laminated solar cell according to claim 1, characterized in that, The grid line contact layer (115) is a single-layer transparent conductive thin film or a stack of multiple transparent conductive thin films.
7. The stacked solar cell according to claim 1, characterized in that, The material of the grid line contact layer (115) includes at least one of ITO, IZO, IWO, and ICO.
8. The stacked solar cell according to claim 1, characterized in that, The thickness of the transparent conductive layer (113) is 5 - 100 nm.
9. The stacked solar cell according to claim 1, characterized in that, The metal grid lines (114) are formed by at least one of screen printing, electrospraying, inkjet printing, and laser transfer printing methods.
10. A method for preparing a tandem solar cell for preparing the tandem solar cell according to any one of claims 1-9, wherein the tandem solar cell (10) comprises a bottom cell (11) and a perovskite top cell (12), characterized in that, After forming the transparent conductive layer (113) and the metal grid lines (114) disposed on the transparent conductive layer (113) in the perovskite top cell (12), it includes: Forming a grid line contact layer (115) to at least cover the connection between the metal grid lines (114) and the transparent conductive layer (113).
11. A photovoltaic module, characterized in that, The photovoltaic module includes the tandem solar cell according to any one of claims 1 - 9.