A solar cell module, a tandem solar cell and a manufacturing method thereof

Abstract

A solar cell module, a tandem solar cell and a manufacturing method thereof belong to the field of photovoltaics. The tandem solar cell includes a perovskite cell and a silicon-based cell that are integrated through a tunneling junction. Among them, the perovskite cell has a front electrode, and the silicon-based cell has a front electrode and a back electrode. This cell can generate electricity through incident light on both sides, so that the direct light-receiving surface can be changed by flipping for power generation. Therefore, in this cell, the silicon-based cell is not affected by the light absorption of the perovskite cell, ensuring the efficiency and power generation of the silicon-based cell.

Description

Technical Field

[0001] The present application relates to the field of photovoltaics, and more particularly, to a solar cell module, a tandem solar cell, and a method for manufacturing the same. Background Art

[0002] Due to its outstanding advantages such as high photoelectric conversion efficiency, low cost, and simple manufacturing, perovskite solar cells have become one of the most promising solar cells and a research hotspot.

[0003] Currently, the efficiency of the top cell of perovskite solar cells has reached 25.2%. The material bandgap applied to perovskite solar cells is generally greater than 1.5 eV, and through doping, the bandgap of the perovskite absorption layer can be further increased to more than 1.65 eV.

[0004] The broadband-gap perovskite absorption layer is very conducive to forming a tandem cell with crystalline silicon solar cells. Currently, the photoelectric conversion efficiency of tandem solar cells composed of perovskite and crystalline silicon has reached 28%.

[0005] However, the service life of perovskite cells has always been a major problem. The instability of the perovskite structure severely restricts the development of tandem cells, resulting in no tandem cell modules on the current market. Therefore, how to give full play to the advantages of perovskite cells without affecting the service life of silicon-based cells is one of the key points for future development. Summary of the Invention

[0006] Based on the above deficiencies, the present application provides a solar cell module, a tandem solar cell, and a method for manufacturing the same, so as to partially or completely improve, or even solve, the problem of the short service life of perovskite cells and silicon-based solar cells in related technologies.

[0007] The present application is implemented as follows:

[0008] In a first aspect, an example of the present application provides a tandem solar cell.

[0009] The tandem solar cell includes a perovskite sub-cell, a tunneling junction, and a silicon-based sub-cell, and the perovskite sub-cell is combined with the silicon-based sub-cell through the tunneling junction.

[0010] Among them, the perovskite sub-cell serves as the top cell of the tandem solar cell. The front surface of the perovskite sub-cell is provided with a top electrode through a first transparent conductive layer.

[0011] The silicon-based sub-cell serves as the bottom cell of the tandem solar cell. The front surface of the silicon-based sub-cell has a first bonding region and a second bonding region located outside the first bonding region. And, a secondary electrode is provided in the second bonding region, and the back surface of the silicon-based sub-cell is provided with a bottom electrode through a second transparent conductive layer.

[0012] The tunneling junction has opposite top and bottom surfaces. The tunneling junction is configured to bond with the back surface of the perovskite sub-cell at the top surface and with the first bonding region of the silicon-based sub-cell at the bottom surface, so that the perovskite sub-cell is combined with the silicon-based sub-cell.

[0013] In a second aspect, an example of the present application provides a method for manufacturing a tandem solar cell, including the following steps:

[0014] Provide an N-type silicon wafer that has been textured and has intrinsic amorphous silicon layers formed on the back and front surfaces respectively, and form a P-type amorphous silicon layer on one of the intrinsic amorphous silicon layers and an N-type amorphous silicon layer on the other intrinsic amorphous silicon layer.

[0015] Form a first transparent conductive layer on the N-type amorphous silicon layer, and form a first grid line electrode on the first transparent conductive layer.

[0016] Manufacture a tunneling junction on a first region of the P-type amorphous silicon layer respectively, manufacture a second transparent conductive layer on a second region of the P-type amorphous silicon layer, and form a second grid line electrode on the second transparent conductive layer, where the second region is located on the periphery of the first region.

[0017] Stack and manufacture a perovskite absorption layer, a hole transport layer, and a third transparent conductive layer in sequence on the tunneling junction.

[0018] Set a third grid line electrode on the third transparent conductive layer.

[0019] In a second aspect, an example of the present application provides a method for manufacturing a tandem solar cell, including the following steps:

[0020] Provide an N-type silicon wafer that has been textured and has intrinsic amorphous silicon layers formed on the back and front surfaces respectively, and form a P-type amorphous silicon layer on one of the intrinsic amorphous silicon layers and an N-type amorphous silicon layer on the other intrinsic amorphous silicon layer.

[0021] Form a first transparent conductive layer on the P-type amorphous silicon layer, and form a first grid line electrode on the first transparent conductive layer.

[0022] Manufacture a tunneling junction on a first region of the N-type amorphous silicon layer respectively, manufacture a second transparent conductive layer on a second region of the N-type amorphous silicon layer, and form a second grid line electrode on the second transparent conductive layer, where the second region is located on the periphery of the first region.

[0023] Stack and manufacture a perovskite absorption layer, an electron transport layer, and a third transparent conductive layer in sequence on the tunneling junction.

[0024] Set a third grid line electrode on the third transparent conductive layer.

[0025] In a fourth aspect, an example of the present application provides a solar cell module. It mainly consists of a frame, an inner structure constrained by the frame, and a junction box provided on the frame.

[0026] Among them, the inner structure includes a battery cell array, a front encapsulation layer, and a back encapsulation layer.

[0027] The battery cell array is in a chip structure and is optionally formed by connecting in series a plurality of the above-mentioned tandem solar cells. And the positive and negative electrodes of the battery cell array are respectively led out and connected to the junction box.

[0028] The front encapsulation layer includes a first encapsulation medium and a first glass stacked in sequence on the front of the battery cell array. The back encapsulation layer includes a second encapsulation medium and a second glass stacked in sequence on the back of the battery cell array.

[0029] In the above implementation process, the tandem solar cell provided by the embodiment of the present application is a double-sided tandem cell, and respectively includes a perovskite solar cell and a silicon-based solar cell. Both sides of the tandem solar cell can receive light for power generation. Thus, within the lifespan of the perovskite cell, light enters from the front (the perovskite solar cell side), and both sub-cells can receive light for power generation; when the perovskite cell reaches the end of its lifespan, the battery cell is flipped, and light enters from the back (the silicon-based solar cell side). BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art.

[0031] Figure 1 It is a schematic structural diagram of a known solar cell;

[0032] Figure 2 It is a schematic structural diagram of the tandem solar cell provided by the embodiment of the present application;

[0033] Figure 3 Shows Figure 2 The front view of the tandem solar cell in

[0034] Figure 4 Shows Figure 2 The back view of the tandem solar cell in

[0035] Figure 5 It shows a schematic structural diagram of the solar cell module in the example of the present application.

[0036] Icons: 101 - Back electrode; 102 - Back transparent conductive layer; 103 - Amorphous silicon p-layer; 104 - Intrinsic amorphous silicon layer; 105 - Crystalline silicon; 106 - Intrinsic amorphous silicon layer; 107 - Amorphous silicon n-layer; 108 - Nanocrystalline silicon n-layer; 109 - Nanocrystalline silicon p-layer; 1010 - Hole transport layer; 1011 - Absorption layer; 1012 - Electron transport layer; 1013 - Front transparent conductive layer; 1014 - Front electrode; 201 - Bottom electrode; 202 - Back transparent conductive layer; 203 - Amorphous silicon n-layer; 204 - Amorphous silicon i-layer; 205 - Crystalline silicon wafer; 206 - Amorphous silicon i-layer; 207 - Amorphous silicon p-layer; 208 - Front transparent conductive layer; 209 - Auxiliary electrode; 210 - Tunneling junction; 211 - Electron transport layer; 212 - Absorption layer; 213 - Hole transport layer; 214 - Front transparent conductive layer; 215 - Top electrode; 400 - Silicon-based sub-cell; 401 - Perovskite sub-cell; 500 - Solar cell module; 501 - Frame; 502 - Front encapsulation layer; 5021 - First glass; 5022 - First encapsulation medium; 503 - Array of solar cells; 504 - Back encapsulation layer; 5041 - Second encapsulation medium; 5042 - Second glass; 506 - Inner structure. Detailed implementation mode

[0037] The embodiments of the present application will be described in detail below in conjunction with the examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present application and should not be construed as limiting the scope of the present application. For those not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. Those reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0038] Perovskite solar cells have unique properties and thus have become a hot research topic. As a mature solar cell technology, silicon-based solar cells also have their own unique advantages. Therefore, how to combine the advantages of perovskite solar cells and silicon-based solar cells to make them cooperate better has become a difficult point in this field.

[0039] One of the key problems is that the stability of perovskite is worse than that of silicon-based materials. Therefore, the lifespan of perovskite is usually lower than that of silicon-based materials. When the two are combined, the entire battery often fails due to the failure of the perovskite solar cell. Therefore, in the solution of combining perovskite solar cells and silicon-based solar cells, how to extend the service life of the battery is particularly important.

[0040] In order to study the performance and characteristics of perovskite solar cells and silicon-based solar cells, the inventor implemented a perovskite-silicon composite tandem solar cell, the structure of which is as Figure 1 shown.

[0041] The back electrode 101 is a back conductive grid line (grid line electrode), generally a silver grid. It can be fabricated by screen printing. The back transparent conductive layer 102 is generally indium tin oxide (ITO). It can be fabricated by magnetron sputtering deposition, with a thickness of about 80 nm.

[0042] The thickness of the amorphous silicon p-layer 103 is generally 10 nm. It can be fabricated by Plasma-Enhanced Chemical Vapor Deposition (PECVD). The intrinsic amorphous silicon layer 104 (amorphous silicon i-layer) has a thickness of generally 10 nm. It can be fabricated by Plasma-Enhanced Chemical Vapor Deposition (PECVD). The crystalline silicon 105 can be an n-type silicon wafer or a p-type silicon wafer. Its thickness is generally 150 to 250 microns. The amorphous silicon i-layer (intrinsic amorphous silicon layer 106) has a thickness of generally 10 nm. It can be fabricated by Plasma-Enhanced Chemical Vapor Deposition (PECVD). The amorphous silicon n-layer 107 has a thickness of generally 10 nm. It can be fabricated by Plasma-Enhanced Chemical Vapor Deposition (PECVD).

[0043] The film layers from the amorphous silicon p-layer 103 to the amorphous silicon n-layer 107 together form the semiconductor layer of the SHJ cell, where the negative electrode is in contact with the tunneling junction and the positive electrode is in contact with the back transparent conductive layer 102.

[0044] The thickness of the nano-silicon n-layer 108 is generally 20 nm, and it is fabricated by Plasma-Enhanced Chemical Vapor Deposition (PECVD). Nano-silicon refers to crystalline silicon particles with a diameter less than 5 nm. The thickness of the nano-silicon p-layer 109 is generally 20 nm. It is fabricated by Plasma-Enhanced Chemical Vapor Deposition (PECVD). The nano-silicon n-layer 108 and the nano-silicon p-layer 109 together form the tunneling junction, that is, the tunneling junction is a composite layer, a structural layer where electrons and holes recombine.

[0045] The hole transport layer 1010 material of the perovskite solar cell is generally an organic small molecule material such as PTAA, spiro-TTB, spiro-OMeTAD, etc. The absorption layer 1011 of the perovskite solar cell (i.e., the perovskite material layer) has the material of FA 1-x Cs x PbI 3 , generally where 0.1 < x < 0.3. The electron transport layer 1012 of the perovskite solar cell has the material of SnO 2 、TiO 2 、ZnO. Generally, it is fabricated by Atomic Layer Deposition (ALD), with a thickness of generally 50 nm.

[0046] The hole transport layer 1010 to the electron transport layer 1012 together constitute the semiconductor layer of the perovskite solar cell, where the positive electrode is in contact with the tunneling junction and the negative electrode is in contact with the front transparent conductive layer 1013.

[0047] The front transparent conductive layer 1013 is generally indium tin oxide (ITO). It can be fabricated by magnetron sputtering with a thickness of 80 nm. The front conductive grid line is the front electrode 1014, generally a silver grid, which is fabricated by screen printing.

[0048] When the above solar cell operates, light enters the perovskite-silicon heterojunction solar cell through the front silver grid (front electrode 1014) and the front transparent conductive layer 1013. Due to the difference in the band gaps of the perovskite material and the silicon material, they have characteristic absorption of light with different wavelengths. Therefore, the response width to the spectrum of the two is larger.

[0049] Among them, for the light entering the solar cell, the part with short wavelength (less than 800 nm) is absorbed by the perovskite absorption layer 1011, generating electron-hole pairs. The photo-generated electrons migrate to the electron transport layer 1012, and the holes migrate to the hole transport layer 1010.

[0050] Among them, the long wavelength light from 800 nm to 1200 nm is absorbed by the absorption layer (crystalline silicon 105) of the silicon heterojunction (Silicon Hetero-Junction, SHJ) solar cell, generating electron-hole pairs. The electrons migrate to the amorphous silicon n-layer 107, and the holes migrate to the amorphous silicon p-layer 103.

[0051] The holes migrating from the perovskite layer solar cell and the electrons migrating from the SHJ solar cell recombine at the tunneling junction (electron and hole recombination layer, including the nano-silicon n-layer and the nano-silicon p-layer).

[0052] At the same time, the electrons of the tandem solar cell are collected through the front transparent conductive layer 1013 and the front silver grid, that is, the front electrode 1014, and form the negative electrode of the tandem solar cell. The holes of the tandem solar cell are collected through the back transparent conductive layer 102 and the back silver grid, that is, the back electrode 101, to form the positive electrode of the tandem solar cell.

[0053] Thus, the tandem solar cell completes a process of forming and separating carriers by the photovoltaic effect. It can supply power externally through an external circuit or a load.

[0054] The electrical characteristics of this tandem solar cell can be partially reflected by the current-voltage curve (J-V curve). Three characteristic parameters, namely the short-circuit current, the maximum power output point, and the open-circuit voltage, can be focused on from this curve, or other electrical characteristic parameters such as the photoelectric conversion efficiency can also be investigated through other testing means.

[0055] The open-circuit voltage (V oc ) of the tandem solar cell is equal to the sum of the open-circuit voltages of the perovskite solar cell and the SHJ cell; the short-circuit current density (J sc ) of the tandem cell is equal to the smaller of the short-circuit current densities of the perovskite solar cell and the SHJ cell.

[0056] Although the above-mentioned tandem cell can improve the performance of the cell, such as light energy utilization rate and photoelectric conversion efficiency. However, as mentioned above, due to the characteristics of the perovskite absorption layer and the hole transport layer materials in the perovskite cell, the absorption layer and the hole transport layer are highly sensitive to impurities such as water and are prone to decomposition, resulting in poor structural stability. When the absorption layer and the hole transport layer of the perovskite cell are damaged, the entire tandem cell cannot continue to work. In other words, the perovskite cell with a lifespan usually within 10 years is difficult to match the silicon-based solar cell with a lifespan of 20 to 30 years.

[0057] In order to alleviate or solve the above problems, a major research direction lies in improving the materials of the perovskite absorption layer and the hole transport layer. However, disappointingly, most of the perovskite materials known currently have varying degrees of decomposition. Such a situation is particularly prominent and obvious when the perovskite is exposed to high humidity, high temperature, strong light, and oxygen-rich conditions, etc. Among them, the decomposition effect of high humidity on the perovskite is more significant. Therefore, this poses quite high requirements for the encapsulation of solar cell devices, thus bringing huge obstacles to its application as a commercial product.

[0058] In view of such a situation, the inventor attempts to start from the structure of the cell. The inventor believes that compared with improving the cell based on perovskite and silicon-based materials from the material aspect, the improvement in its structure may bring visible advantages and relatively lower implementation difficulty.

[0059] From the perspective of the cell structure implemented by the inventor, the main manifestation of its defect is that after the perovskite cell fails, the entire tandem cell cannot continue to serve. And one of the reasons for this problem is that the failure of the perovskite cell makes the photo-generated electrons of the cell unable to be generated and transported normally, thus making the positive electrode of the cell unable to collect electrons normally. Therefore, the cell cannot supply power to the external load either.

[0060] Since the silicon-based solar cell has a longer lifespan, in order to enable it to work after the perovskite cell fails, the inventor improves the silicon-based cell in the tandem cell. One of the main means is to add additional electrodes to the silicon-based cell. Thus, when the perovskite cell fails, the silicon-based cell can still supply power to the external as an independent cell.

[0061] In an example, such an innovative battery can, in some examples, be represented by a flipable double-sided power generation perovskite / SHJ tandem solar cell. From a broader perspective, this battery is also a tandem solar cell. It can be incident by light on both sides (front and back).

[0062] When the perovskite battery is in normal service, the perovskite battery side serves as the light incident side. The back electrode and the front electrode of this tandem battery are used as the positive and negative electrodes of the battery.

[0063] When the perovskite fails, the tandem solar cell is flipped, and the silicon-based battery side serves as the light incident side. The back electrode of this tandem battery and the additional electrode provided on the silicon-based battery as described above are used as the positive and negative electrodes of the battery.

[0064] Thus, the tandem solar cell proposed by the inventor and based on perovskite and silicon-based materials will have a longer service life. At the same time, during the service cycle of the perovskite, the battery combines the advantages of the perovskite battery and the silicon-based material battery, thereby improving the open-circuit voltage and the battery efficiency of the battery, and increasing the levelized cost of electricity energy (LCOE) of the battery.

[0065] The following specifically describes a tandem solar cell and its manufacturing method according to an embodiment of the present application:

[0066] Generally speaking, the tandem solar cell in the example mainly includes a top cell and a bottom cell that are combined with each other. In the first stage of the service life cycle of the battery, the top cell and the bottom cell cooperate to supply power at the same time; in the latter stage of the service life cycle of the battery, it is mainly the bottom cell that works to supply power outward. Therefore, as described above, the top cell refers to a perovskite-based solar cell, and the bottom cell refers to a silicon-based material solar cell.

[0067] In the combined area of the top cell and the bottom cell, as the carrier recombination area, the two are combined through a tunneling junction. And in some examples, this tunneling junction can adopt a stack, such as a bilayer structure design (such as p-type nanocrystals and n-type nanocrystals).

[0068] For different structural forms of the tunneling junction, the other layers in the corresponding tandem solar cell can also be adjusted accordingly. For example, for Solution 1, the front electrode of the tandem solar cell is fabricated and used as the positive electrode, and the back electrode of the tandem solar cell is fabricated and used as the negative electrode. For example, for Solution 2, the front electrode of the tandem solar cell is fabricated and used as the negative electrode, and the back electrode of the tandem solar cell is fabricated and used as the positive electrode. In the example of the present application, Solution 1 is taken as an example for illustration.

[0069] In addition, as one of the features designed for the corresponding improvement of the stacked solar cell with a relatively longer service life, the bottom cell of the silicon-based material solar cell also has an additional electrode (which will appear again as a secondary electrode later and is not described here). This additional electrode is adapted to the back electrode of the stacked solar cell. When the back electrode of the stacked solar cell is the positive electrode, this additional electrode is the negative electrode, and vice versa.

[0070] Therefore, in the example of this application, the stacked solar cell includes a perovskite sub-cell 401, a tunneling junction 210, and a silicon-based sub-cell 400. It should be noted that the stacked solar cell designed in the example of this application is a vertical junction solar cell, mainly including alternately arranged P-type layers and N-type layers, which form different numbers of PN junctions. Or some PN junctions can also be replaced with homojunctions according to needs, such as NN+ type junctions (high-low junctions), etc.

[0071] Top cell

[0072] The perovskite sub-cell 401 serves as the top cell, and the front surface of the perovskite sub-cell 401 is provided with a top electrode through a first transparent conductive layer. In the perovskite sub-cell 401, the perovskite material serves as the photosensitive layer. Among them, other functional layers can also be included in the sub-cell, such as a hole transport layer, an electron transport layer, etc. According to different requirements, different selections of perovskite materials can be made. The perovskite material usually has a structure in the form of ABX 3 , where A is a mixture of FA, MA, and Cs in any proportion, B is one or two of Pb ions and Sn ions; X is selected from at least one of I ions, Cl ions, and Br ions.

[0073] For example, FAPbI 3 , MAPb(I 1-x Br x ), 3、 MAPbI 1-x (SCN) x , (BA) 2 (MA) n-1 Pb n I 3n+1 , and so on. In the example of this application, the perovskite material in the perovskite sub-cell is (FA) 1-x Cs x PbI 3 , and 0.1 < x < 0.3.

[0074] Bottom cell

[0075] The silicon-based sub-cell 400 serves as the bottom cell, and the front surface of the silicon-based sub-cell 400 has a first bonding region and a second bonding region located outside the first bonding region. A sub-electrode is provided in the second bonding region, and a bottom electrode is provided on the back surface of the silicon-based sub-cell 400 through a second transparent conductive layer.

[0076] As the name implies, a silicon-based sub-cell is a semiconductor cell made of silicon materials. According to the classification of its production materials, it can have various forms. For example, the silicon-based sub-cell is a heterojunction cell, such as a junction made of silicon materials; or, a heterojunction cell made of silicon materials and materials such as germanium. In addition, according to the type of the formed junction, the structure in the heterojunction cell can be a homotype heterojunction (such as a P+ / P junction or an N / N- junction or a P- / P junction or an N / N+ junction), or a heterotype heterojunction (such as a P-n or p-N) junction, and a multi-layer heterojunction is called a heterostructure. Or, the silicon-based sub-cell can be classified into a single-junction cell according to the number of junctions in the silicon-based sub-cell.

[0077] Tunnel junction

[0078] The tunneling junction 210 has opposite top and bottom surfaces. The tunneling junction is configured in such a way that the top surface is combined with the perovskite sub-cell 401 (back surface), and the bottom surface is combined with the first bonding region of the silicon-based sub-cell 400 (front surface) to enable the perovskite sub-cell and the silicon-based sub-cell to be combined.

[0079] Generally, for the electrodes of a solar cell, the electrode on the front surface (light incident side) is usually selected to be finger-shaped, while the back surface can be selected to be a flat plate shape. In the present application, the stacked solar cell has the characteristic of double-sided light incidence and photovoltaic power generation. Therefore, the top electrode, the bottom electrode, and the sub-electrode therein are all selected to be grid line electrodes. Regarding the production materials of the electrodes, the top electrode, the bottom electrode, and the sub-electrode can be made of the same or different conductive materials. The conductive material is, for example, silver, a titanium copper alloy, or a tin copper alloy.

[0080] As an alternative specific example, the silicon-based sub-cell in the stacked solar cell is selected to be a heterojunction cell and has an N-type amorphous silicon layer, a first intrinsic amorphous silicon layer, an N-type crystalline silicon layer, a second intrinsic amorphous silicon layer, and a P-type amorphous silicon layer stacked in sequence. In this structure, the N-type crystalline silicon layer is used as the substrate and has a greater thickness than other structural layers in the silicon-based sub-cell.

[0081] In another alternative example, the silicon-based sub-cell is a heterojunction cell and has an N-type amorphous silicon layer, a first intrinsic amorphous silicon layer, a P-type crystalline silicon layer, a second intrinsic amorphous silicon layer, and a P-type amorphous silicon layer stacked in sequence. In this structure, the P-type crystalline silicon layer is used as the substrate and has a greater thickness than other structural layers in the silicon-based sub-cell.

[0082] Correspondingly, the perovskite solar cell has an electron transport layer, a perovskite layer, and a hole transport layer stacked in sequence.

[0083] For the structure of the tandem solar cell based on the above structure, refer to Figure 2 , Figure 3 and Figure 4 . Among them, Figure 2 is the front view of the tandem solar cell and shows the structure of one side of the cell. Figure 3 is the top view of the tandem solar cell and shows the electrode distribution on the front side of the cell. Figure 4 is the bottom view of the tandem solar cell and shows the electrode distribution on the back side of the cell.

[0084] This cell is based on a perovskite / SHJ tandem cell and has the characteristic of bifacial power generation. It has the following structure from bottom to top.

[0085] The bottom electrode 201 is the back conductive grid line, and can be made of silver, copper, or a composite of it and multiple metals such as Ti / Cu, Sn / Cu. The preparation method of the bottom electrode 201 can be screen printing, that is, a layer of metal silver grid line is prepared on the back transparent conductive layer 202 through screen printing. The thickness of the silver grid prepared by the screen printing method is 5 micrometers to 200 micrometers, and the width is 1 micrometer to 200 micrometers. The thickness of the copper grid line is 100 nm to 20 micrometers, and the width is 1 micrometer to 200 micrometers. Another method of making the bottom electrode is electroplating. First, a thin layer of titanium (Ti) or tin (Sn) is evaporated or sputtered on the back transparent conductive layer 202 through a mask as a precursor, and then a copper grid line is electroplated on the precursor of Ti or Sn in a copper salt solution. The thickness of the grid line prepared by the electroplating method is 100 nanometers to 20 micrometers, where the thickness of the precursor is 5 nm to 100 nm, and the width is 1 micrometer to 200 micrometers.

[0086] The back transparent conductive layer 202 can be made of indium tin oxide (ITO), indium tungsten oxide (IWO), aluminum-doped zinc oxide AZO, or boron-doped zinc oxide BZO. Its manufacturing method is, for example, magnetron sputtering deposition or reactive plasma deposition (RPD), and the thickness is 50 nm to 500 nm.

[0087] The amorphous silicon n-layer 203 is made by plasma-enhanced chemical vapor deposition (PECVD), and its thickness is 2 nm to 200 nm.

[0088] The amorphous silicon i-layer 204 (intrinsic amorphous silicon) is made by plasma-enhanced chemical vapor deposition (PECVD), and its thickness is 2 nm to 50 nm.

[0089] The crystalline silicon wafer 205 can be an n-type silicon wafer or a p-type silicon wafer, and the thickness of the silicon wafer is 150 micrometers to 250 micrometers.

[0090] The amorphous silicon i-layer 206 is fabricated by plasma-enhanced chemical vapor deposition (PECVD) and has a thickness of 2 nm to 50 nm.

[0091] The amorphous silicon p-layer 207 is fabricated by plasma-enhanced chemical vapor deposition (PECVD) and has a thickness of 2 nm to 100 nm.

[0092] The silicon-based semiconductor layer of the cell is composed of the above-mentioned amorphous silicon n-layer 203 to amorphous silicon p-layer 207 films to form an SHJ cell. And the front side of the SHJ cell is in contact with the tunneling junction, and the negative electrode (as an example of the aforementioned bottom electrode 201) is in contact with the back transparent conductive layer. The front side of the SHJ cell is also connected to the auxiliary electrode 209 through the transparent conductive layer.

[0093] Using a mask, two stacked tin oxide layers are fabricated in a selected area (inner area) on the amorphous silicon p-layer 207 by magnetron sputtering to form a tunneling junction. The two tin oxide layers include a bonding layer in direct contact with the amorphous silicon p-layer 207, that is, the tunneling junction 210, and an electron transport layer 211 in direct contact with the bonding layer (which can also be used as the electron transport layer of a perovskite solar cell).

[0094] The transparent conductive layer is fabricated on another selected area (outer area) on the amorphous silicon p-layer 207 by magnetron sputtering deposition or reactive plasma deposition (RPD). This conductive layer serves as the front transparent conductive layer 208 of the SHJ cell (silicon-based heterojunction HJT cell). And, it can generally be selectively made of indium tin oxide (ITO), indium tungsten oxide (IWO), and has a thickness of 50 nm to 150 nm.

[0095] The auxiliary electrode 209 is a conductive grid line, and the material can be silver, copper, or a composite material of multiple metals such as Ti / Cu, or Sn / Cu.

[0096] The material for fabricating the absorption layer 212 of the perovskite solar cell is FA 1-x Cs x PbI 3 , where 0.1 < x < 0.3.

[0097] The hole transport layer 213 of the perovskite solar cell is selected from nickel oxide NiO or cuprous thiocyanate (CuSCN), and has a thickness of 5 nm to 100 nm. Among them, nickel oxide (NiO) can be fabricated by magnetron sputtering, reactive plasma deposition (RPD), or chemical vapor deposition. The chemical vapor deposition includes atomic layer deposition (ALD), low-pressure chemical vapor deposition (LPCVD), and metal-organic chemical vapor deposition (MOCVD). Cuprous thiocyanate (CuSCN) is fabricated by vacuum evaporation.

[0098] The front transparent conductive layer 214 can be made by magnetron sputtering deposition or reactive plasma deposition (RPD) using indium tin oxide (ITO) or indium tungsten oxide (IWO), with a thickness of 50 nm to 150 nm.

[0099] The top electrode 215 is a front conductive grid line, and its material can be silver, copper, or a composite material of multiple metals, such as Ti / Cu, Sn / Cu.

[0100] To make it easier for those skilled in the art to implement the above-mentioned scheme of the stacked solar cell, the following also gives its manufacturing method. Due to the different structures of the SHJ cells, the cells have different manufacturing methods.

[0101] The first manufacturing method includes:

[0102] Step S301: Provide an N-type silicon wafer that has been textured and has intrinsic amorphous silicon layers formed on the back and front respectively, and form a P-type amorphous silicon layer on one of the intrinsic amorphous silicon layers and an N-type amorphous silicon layer on the other intrinsic amorphous silicon layer.

[0103] Step S302: Form the first transparent conductive layer on the N-type amorphous silicon layer, and form the first grid line electrode on the first transparent conductive layer.

[0104] Step S303: Make a tunneling junction on the first region of the P-type amorphous silicon layer, make the second transparent conductive layer on the second region of the P-type amorphous silicon layer, and form the second grid line electrode on the second transparent conductive layer, where the second region is located on the periphery of the first region.

[0105] Step S404: Stack and make a perovskite absorption layer, a hole transport layer, and a third transparent conductive layer in sequence on the tunneling junction.

[0106] Step S405: Set the third grid line electrode on the third transparent conductive layer.

[0107] The second manufacturing method includes:

[0108] Step S501: Provide an N-type silicon wafer that has been textured and has intrinsic amorphous silicon layers formed on the back and front respectively, and form a P-type amorphous silicon layer on one of the intrinsic amorphous silicon layers and an N-type amorphous silicon layer on the other intrinsic amorphous silicon layer.

[0109] Step S502: Form the first transparent conductive layer on the P-type amorphous silicon layer, and form the first grid line electrode on the first transparent conductive layer.

[0110] Step S503: A tunneling junction is fabricated on the first region of the N-type amorphous silicon layer, a second transparent conductive layer is fabricated on the second region of the N-type amorphous silicon layer, and a second gate line electrode is formed on the second transparent conductive layer, where the second region is located on the periphery of the first region.

[0111] Step S504: A perovskite absorption layer, an electron transport layer, and a third transparent conductive layer are sequentially laminated on the tunneling junction.

[0112] Step S505: The third gate line electrode is disposed on the third transparent conductive layer.

[0113] Furthermore, based on the aforementioned laminated solar cell fabricated, an application example thereof is also provided in the examples of the present application, namely, a solar cell module 500, the structure of which is referred to Figure 5 .

[0114] The solar cell module 500 mainly consists of a frame 501, an inner structure 506 constrained by the frame 501, and a junction box (not shown in the figure) disposed on the frame.

[0115] Among them, the frame 501 provides constraints to combine other components in the solar cell module 500 into an integrated and stable overall structure. It can be made of a metal material, and its shape is generally square. The junction box is used to gather and converge the electrodes of the battery, facilitating the connection to the electrical load. In some other examples, the frame may not be used in the battery structure, such as the butyl glue encapsulation of a double-glass module.

[0116] Among them, the inner structure 506 mainly includes a battery and other components beneficial for encapsulation and combination.

[0117] For example, the inner structure 506 includes a sheet-type battery cell array 503, a front encapsulation layer 502, and a back encapsulation layer 504. The battery cell array 503 is optionally formed by connecting multiple laminated solar cells in series (in an array). The positive and negative electrodes of the battery cell array are respectively led out and connected to the junction box.

[0118] The front encapsulation layer 502 includes a first encapsulation medium 5022 (such as EVA) and a first glass 5021 sequentially laminated on the front of the battery cell array. The back encapsulation layer 504 includes a second encapsulation medium 5041 and a second glass 5042 sequentially laminated on the back of the battery cell array.

[0119] The following further describes in detail a laminated solar cell and its manufacturing method of the present application in conjunction with embodiments.

[0120] Embodiment 1

[0121] On the upper and lower surfaces of the cleaned and texturized n-type silicon wafers, an intrinsic amorphous silicon layer is deposited on each by plasma-enhanced chemical vapor deposition, with thicknesses of 10 nm and 8 nm respectively.

[0122] Then, a p-type amorphous silicon layer with a thickness of 10 nm is deposited on the 8-nm-thick intrinsic amorphous silicon layer. An n-type amorphous silicon layer with a thickness of 15 nm is deposited on the 10-nm-thick intrinsic amorphous silicon layer.

[0123] A back transparent conductive layer is prepared on the n-type amorphous silicon layer by magnetron sputtering, with the material being indium tin oxide (ITO) and a thickness of 120 nm. Silver grid lines are prepared on the magnetron-sputtered back transparent conductive layer by screen printing, with a distance of 2 mm between the silver grid lines. The height of each silver grid line is 20 μm and the width is 50 μm.

[0124] A mask plate is set on the p-type amorphous silicon layer, and then a tunneling junction (composed of a double layer) with a thickness of 50 nm is prepared in the stacked area by magnetron sputtering using tin dioxide as the target material on the p-type amorphous silicon layer. Also, a front indium tin oxide film layer of the SHJ cell with a thickness of 100 nm is prepared on the p-type amorphous silicon layer by magnetron sputtering using a corresponding template. Then, silver grid lines are prepared by screen printing, with the height of the silver grid lines being 20 μm and the width being 50 μm.

[0125] FA is deposited on the tin dioxide serving as the electron transport layer in the tunneling junction 0.9 MA 0.1 PbI 3 perovskite absorption layer with a film thickness of 400 nm. Deposition method: vacuum co-evaporation; the evaporation raw materials are FAI, MAI, and PbI2 respectively; conditions are: the evaporation temperature of FAI is 200 °C, the evaporation temperature of MAI is 120 °C, the evaporation temperature of PbI 2 is 400 °C, and the temperature of the substrate material is 30 °C.

[0126] A hole transport layer with a film thickness of 80 nm is deposited on the deposited perovskite absorption layer using polythiophene acetic acid. The deposition method is vacuum evaporation, the evaporation temperature of the raw material is 150 °C, and the substrate temperature is 30 °C.

[0127] A front transparent conductive layer with a film thickness of 80 nm is deposited on the deposited hole transport layer using indium tin oxide by plasma deposition on the front side.

[0128] Multiple silver grid lines are prepared on the deposited transparent conductive layer by screen printing, with a distance of 2 mm between the silver grid lines, and the height of each silver grid line is 20 μm and the width is 50 μm.

[0129] Example 2

[0130] On both surfaces of the cleaned and texturized n-type silicon wafers, an intrinsic amorphous silicon layer is deposited by plasma-enhanced chemical vapor deposition, with a thickness of 10 nm for each layer.

[0131] On the above two intrinsic amorphous silicon layers, a p-type amorphous silicon layer and an n-type amorphous silicon layer are respectively deposited. The thickness of the p-type amorphous silicon layer is 20 nm, and the thickness of the n-type amorphous silicon layer is 15 nm.

[0132] On the p-type amorphous silicon layer, a back transparent conductive layer with a thickness of 200 nm is prepared by magnetron sputtering using aluminum-doped zinc oxide. Then, silver grid lines are prepared by screen printing on this back transparent conductive layer. The distance between the silver grid lines is 2 mm. The height of each silver grid line is 20 μm, and the width is 50 μm.

[0133] On the n-type amorphous silicon, a front transparent conductive layer with a thickness of 120 nm and a material of indium tin oxide for the SHJ cell is prepared using the corresponding mask. And further, silver grid lines are prepared by screen printing. The distance between the silver grid lines is 2 mm. The height of each silver grid line is 20 μm, and the width is 50 μm.

[0134] On the n-type amorphous silicon layer, a tunneling junction with a thickness of 15 nm is also prepared by chemical vapor deposition using nanocrystals as raw materials and using the corresponding mask.

[0135] On top of the tunneling junction, a hole transport layer is prepared by evaporation coating. The material is Spiro-TTB, the substrate temperature is 30 degrees, and the film thickness is 20 nm.

[0136] Then, a perovskite absorption layer is deposited on the hole transport layer Spiro-TTB. The absorption layer material is FA 0.7 MA 0.3 PbI 3 ; The deposition method is vacuum co-evaporation. The evaporation raw materials are FAI, MAI, and PbI2 respectively; the evaporation temperature of FAI is 200 degrees Celsius, the evaporation temperature of MAI is 140 degrees Celsius, and the evaporation temperature of PbI 2 is 400 degrees Celsius. The temperature of the substrate material is 30 degrees Celsius. The film thickness of the perovskite absorption layer is 400 nm.

[0137] On the deposited perovskite absorption layer, an electron transport layer is deposited. The material is tin dioxide, the deposition method is atomic layer deposition, the evaporation temperature of the raw material is 85 degrees Celsius, and the film thickness is 20 nm.

[0138] On the deposited electron transport layer, a front transparent conductive layer is deposited. The material is indium tungsten oxide IWO. The deposition method is reactive plasma deposition, and the deposition film thickness is 80 nm.

[0139] The silver grid lines are prepared by screen printing on the deposited back electrode transparent conductive layer. The height of the silver grid lines is 15 micrometers, and the width is 50 micrometers. The distance between the silver grid lines is 1.5 millimeters.

[0140] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A tandem solar cell, characterized in that, comprising: a perovskite sub-cell as the top cell, and a top electrode is provided on the front surface of the perovskite sub-cell through a first transparent conductive layer; a silicon-based sub-cell as the bottom cell, the front surface of the silicon-based sub-cell has a first bonding region and a second bonding region located outside the first bonding region, a secondary electrode is provided in the second bonding region, and a bottom electrode is provided on the back surface of the silicon-based sub-cell through a second transparent conductive layer; a tunneling junction having opposite top and bottom surfaces, the tunneling junction is configured to bond the top surface to the back surface of the perovskite sub-cell and the bottom surface to the first bonding region of the silicon-based sub-cell, so that the perovskite sub-cell and the silicon-based sub-cell are combined.

2. The tandem solar cell according to claim 1, characterized in that, the silicon-based sub-cell is a homojunction cell or a heterojunction cell; alternatively, the silicon-based sub-cell is a single-junction cell.

3. The tandem solar cell according to claim 1 or 2, characterized in that, in the perovskite sub-cell, a hole transport layer and an electron transport layer are respectively provided on both sides of the perovskite material.

4. The tandem solar cell according to claim 1, characterized in that, the silicon-based sub-cell is a heterojunction cell and has an N-type amorphous silicon layer, a first intrinsic amorphous silicon layer, an N-type crystalline silicon layer, a second intrinsic amorphous silicon layer, and a P-type amorphous silicon layer stacked in sequence, and the silicon-based sub-cell is bonded to the bottom surface of the tunneling junction with the P-type amorphous silicon layer; alternatively, the silicon-based sub-cell is a heterojunction cell and has an N-type amorphous silicon layer, a first intrinsic amorphous silicon layer, a P-type crystalline silicon layer, a second intrinsic amorphous silicon layer, and a P-type amorphous silicon layer stacked in sequence, and the silicon-based sub-cell is bonded to the bottom surface of the tunneling junction with the P-type amorphous silicon layer.

5. The tandem solar cell according to claim 1 or 4, characterized in that, the perovskite sub-cell has an electron transport layer, a perovskite layer, and a hole transport layer stacked in sequence.

6. The tandem solar cell according to claim 1, characterized in that, The perovskite material in the perovskite sub-cell is FA 1-x Cs x PbI 3 , where 0.1 < x < 0.

3.

7. The tandem solar cell according to claim 1, characterized in that, the top electrode, the bottom electrode, and the secondary electrode are all grid line electrodes; alternatively, the top electrode, the bottom electrode, and the secondary electrode are respectively independently made of silver, a titanium copper alloy, or a tin copper alloy.

8. A method for manufacturing a tandem solar cell, characterized in that, comprising: providing an N-type silicon wafer that has been textured and has intrinsic amorphous silicon layers respectively formed on the back and front surfaces, and forming a P-type amorphous silicon layer on one of the intrinsic amorphous silicon layers and an N-type amorphous silicon layer on the other intrinsic amorphous silicon layer; forming a first transparent conductive layer on the N-type amorphous silicon layer and forming a first grid line electrode on the first transparent conductive layer; respectively forming a tunneling junction on a first region of the P-type amorphous silicon layer and a second transparent conductive layer on a second region of the P-type amorphous silicon layer, and forming a second grid line electrode on the second transparent conductive layer, wherein the second region is located outside the first region; A perovskite absorption layer, a hole transport layer, and a third transparent conductive layer are sequentially laminated on the tunneling junction; A third grid line electrode is disposed on the third transparent conductive layer.

9. A manufacturing method of a laminated solar cell, characterized in that, it includes: providing an N-type silicon wafer that has been textured and has an intrinsic amorphous silicon layer formed on the back and the front respectively, and forming a P-type amorphous silicon layer on one of the intrinsic amorphous silicon layers and an N-type amorphous silicon layer on the other intrinsic amorphous silicon layer; forming a first transparent conductive layer on the P-type amorphous silicon layer, and forming a first grid line electrode on the first transparent conductive layer; forming a tunneling junction on a first region of the N-type amorphous silicon layer and a second transparent conductive layer on a second region of the N-type amorphous silicon layer, and forming a second grid line electrode on the second transparent conductive layer, where the second region is located on the periphery of the first region; a perovskite absorption layer, an electron transport layer, and a third transparent conductive layer are sequentially laminated on the tunneling junction; a third grid line electrode is disposed on the third transparent conductive layer.

10. A solar cell module, characterized in that, it mainly consists of a frame, an inner structure constrained by the frame, and a junction box disposed on the frame; wherein, the inner structure includes: a sheet-like array of solar cells, optionally formed by connecting in series a plurality of laminated solar cells according to any one of claims 1 to 7, and the positive and negative electrodes of the solar cell array are respectively led out and connected to the junction box; a front encapsulation layer, including a first encapsulation medium and a first glass sequentially laminated on the front of the solar cell array; a back encapsulation layer, including a second encapsulation medium and a second glass sequentially laminated on the back of the solar cell array.

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