Flexible solar cell

Abstract

The utility model provides a flexible solar cell which comprises a back electrode, a solar cell epitaxial structure and an electrode structure which are sequentially arranged on the surface of a flexible substrate, and the electrode structure comprises a positive electrode and a grid line electrode which are in contact. Wherein the flexible substrate comprises an alloy substrate formed by doping a metal film, so that the toughness of the flexible substrate is improved. Based on the structural arrangement, the metal film is doped to form the alloy substrate, so that the toughness of the metal film is improved, the pressure stress of the solar cell epitaxial structure can be supported, and the flatness of a wafer is kept in the manufacturing process of a solar cell chip; therefore, the flexible solar cell provided by the utility model does not need a temporary substrate / an additional supporting substrate, does not need bonding and de-bonding related processes, reduces the requirements of equipment and materials, and further effectively reduces the production cost of the flexible solar cell.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cells, in particular to a flexible solar cell. Background Art

[0002] II and IV compound solar cells, represented by GaInP / GaInAs / Ge triple-junction solar cells, have the advantages of high photoelectric conversion efficiency, strong radiation resistance, and good temperature characteristics. They are widely used in spacecraft power systems and ground-based high-concentration photovoltaic power stations, and have completely replaced crystalline silicon solar cells as the main power source for spacecraft.

[0003] However, because GaInP / GaInAs / Ge triple-junction solar cells are based on thick, rigid Ge substrates (typically ≥140μm thick), the cell chips are heavy and lack flexibility, increasing the weight and volume of spacecraft solar panels. Conventional flexible thin-film solar cells based on copper indium gallium selenide, cadmium telluride, or amorphous silicon have failed to enter the space application market due to low conversion efficiency and poor stability.

[0004] Flexible solar cells can be rolled up, reducing the size of solar panels, increasing the carrying capacity of spacecraft and reducing launch costs. Furthermore, these high-efficiency flexible thin-film solar cells can also meet the application requirements of near-space vehicles, such as solar-powered drones and unmanned airships. Therefore, flexible solar cells have become a technological development trend due to their light weight, high mass-to-power ratio, and bendability.

[0005] Currently, flexible solar cells are usually realized by performing a secondary temporary bonding process as follows: First, a back electrode is fabricated on the back of the solar cell, and the back electrode is bonded to the first temporary substrate through a first temporary bonding process; then, the epitaxial substrate of the solar cell is separated, and after the front processing is completed on the front of the solar cell, a second temporary substrate (rigid substrate) is bonded to the front of the cell; then, the first temporary substrate and the back electrode are debonded, and a flexible substrate is fabricated on the back electrode; finally, the second temporary substrate is debonded to obtain the desired flexible solar cell. This method has the following problems:

[0006] ① After separating the cell epitaxial substrate, the epitaxial layer is transferred to a metal flexible substrate. The thermal expansion coefficients of the two are quite different, and the metal flexible substrate, which is only tens of microns thick, is not enough to withstand the compressive stress of the cell epitaxial layer. In order to maintain the flatness of the solar cell during the manufacturing process, a temporary substrate (rigid substrate) is required for support. After the front-side process is completed, the supporting substrate is debonded. One-time bonding and debonding are required, which increases the demand for materials and equipment and increases the tape-out time.

[0007] ② The metal flexible substrate and the battery epitaxial layer have different coefficients of thermal expansion (CTE). The two are tightly bonded together. Changes in temperature will cause the two materials to expand or contract at different rates and amounts, which in turn generates thermal stress at the contact interface between the two. Specifically, if the CTE of one material is larger than the other, then when heated, the material with a larger CTE will try to expand more; but because it is tightly bonded to the material with a smaller CTE, it cannot expand freely. This will generate compressive stress at the contact surface of the two materials, causing the battery epitaxial layer to be "crushed."

[0008] In view of this, the inventors specially designed a flexible solar cell, which resulted in this case. Utility Model Content

[0009] The purpose of the utility model is to provide a flexible solar cell to solve the problems of high production cost and low yield of flexible solar cells.

[0010] In order to achieve the above purpose, the technical solution adopted by the present utility model is as follows:

[0011] A flexible solar cell comprises a back electrode, a solar cell epitaxial structure and an electrode structure sequentially arranged on the surface of a flexible substrate, wherein the electrode structure comprises a positive electrode and a grid electrode for forming a contact; wherein the flexible substrate comprises an alloy substrate formed by doping a metal film to improve the toughness of the metal film.

[0012] Preferably, the thermal expansion coefficient of the metal film is greater than the thermal expansion coefficient of the dopant.

[0013] Preferably, the difference between the thermal expansion coefficient of the metal film and the thermal expansion coefficient of the dopant is between 2×10 -6 / ℃ to 20×10 -6 / ℃, including the endpoint values.

[0014] Preferably, the thickness of the metal film is no more than 100 μm.

[0015] Preferably, the Brinell hardness of the dopant is between 60N / mm 2 ~200N / mm 2 Between, including the endpoint values.

[0016] Preferably, the doping concentration of the metal film is 1*10 14 cm -3 ~1*10 19 cm -3 , including the endpoint values.

[0017] Preferably, the metal film includes a stack of one or more of a copper film, an aluminum film, and a titanium film.

[0018] Preferably, the alloy substrate includes a molybdenum-copper alloy substrate, a chromium-aluminum alloy substrate, or a titanium-germanium alloy substrate.

[0019] Preferably, the gate line electrode comprises a transparent electrode or a metal electrode;

[0020] Wherein, the transparent electrode comprises a stack of one or more of an ITO electrode, an IZO electrode, an IGZO electrode, an AZO electrode and a graphene electrode;

[0021] The metal electrode includes one or more stacks of Ag electrodes, Au electrodes, Cu electrodes, and Au / Ag alloy electrodes.

[0022] Preferably, an anti-reflection film is provided between two adjacent gate line electrodes.

[0023] Preferably, the anti-reflection film covers the gate line electrode and exposes at least a portion of the surface of the positive electrode.

[0024] Preferably, the flexible solar cell comprises a flexible multi-junction solar cell or a flexible single-junction solar cell.

[0025] Preferably, the flexible solar cell includes a flexible triple-junction solar cell, and the solar cell epitaxial structure includes a bottom cell, a tunnel junction, an intermediate cell, a tunnel junction and a top cell stacked in sequence on the surface of the back electrode.

[0026] Preferably, the flexible solar cell comprises a flexible double-junction solar cell, and the solar cell epitaxial structure comprises a bottom cell, a tunnel junction and a top cell sequentially stacked on the surface of the back electrode.

[0027] The above-described technical solution indicates that the flexible solar cell provided by the present invention comprises a back electrode, a solar cell epitaxial structure, and an electrode structure sequentially arranged on the surface of a flexible substrate. The electrode structure comprises a positive electrode and a grid electrode that form a contact. The flexible substrate comprises an alloy substrate formed by doping a metal film to increase the toughness of the flexible substrate. Based on this structural arrangement, the alloy substrate is formed by doping the metal film to increase the toughness of the metal film, thereby supporting the compressive stress of the solar cell epitaxial structure and maintaining the flatness of the solar cell chip during the manufacturing process. As such, the flexible solar cell provided by the present invention does not require a temporary substrate or additional support substrate, nor does it require bonding and debonding processes, reducing equipment and material requirements and effectively lowering the production cost of the flexible solar cell.

[0028] Secondly, by setting the thermal expansion coefficient of the metal film to be greater than the thermal expansion coefficient of the dopant, the thermal expansion coefficient of the alloy substrate is reduced, thereby reducing the difference in thermal expansion coefficients between the metal film and the solar cell epitaxial structure, thereby reducing the compressive stress at the alloy contact surface between the solar cell epitaxial structure and the flexible substrate during the alloy doping process of the metal film, thereby further avoiding cracks in the solar cell epitaxial structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0030] Figures 1 to 9 This is a structural schematic diagram corresponding to the method for manufacturing a flexible solar cell provided in Example 1 of the present invention;

[0031] Figure 10 This is a schematic structural diagram of a flexible solar cell provided in Example 2 of the present invention;

[0032] Explanation of symbols in the figure:

[0033] 1. Growth substrate;

[0034] 2. Sacrificial layer or corrosion cutoff layer;

[0035] 3. Solar cell epitaxial structure;

[0036] 4. Back electrode;

[0037] 5. Metal film;

[0038] 6. Dopant;

[0039] 7.1, positive electrode;

[0040] 7.2, grid line electrode;

[0041] 8. Anti-reflection film;

[0042] 31. First ohmic contact layer, 32. GaInP top cell, 33. Tunnel junction, 34. GaAs middle cell, 35. Tunnel junction, 36. InGaAs bottom cell, 37. Second ohmic contact layer. DETAILED DESCRIPTION

[0043] To make the content of the utility model clearer, the content of the utility model is further described below with reference to the accompanying drawings. The utility model is not limited to the specific embodiment. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the utility model.

[0044] Example 1

[0045] like Figure 1 As shown, a method for manufacturing a flexible solar cell includes the following steps:

[0046] S01、 Figure 2 As shown, a growth substrate 1 is provided;

[0047] Specifically, in one embodiment of the present application, in order to obtain the flexible battery, the growth substrate 1 is a GaAs substrate. The band gap of the GaAs material is well matched with the solar spectrum, which is conducive to the growth of high-efficiency solar cells.

[0048] Based on the above content, in a preferred embodiment of the present application, a sacrificial layer or corrosion stop layer 2 is further provided on the surface of the growth substrate 1. The sacrificial layer can be used to subsequently separate the growth substrate 1 from the solar cell. Specifically, the sacrificial layer material includes but is not limited to AlAs, and the corrosion stop layer includes but is not limited to a GaInP corrosion stop layer.

[0049] S02, such as Figure 3 As shown, a solar cell epitaxial structure 3 is flip-chip grown on the surface of the growth substrate 1;

[0050] Specifically, the solar cell epitaxial structure 3 may include a structure suitable for a flexible multi-junction gallium arsenide solar cell or a flexible single-junction gallium arsenide solar cell, such as a flexible double-junction solar cell, a flexible triple-junction solar cell, or a single-junction gallium arsenide solar cell. For example, the flexible single-junction gallium arsenide solar cell includes, but is not limited to, a single-junction gallium arsenide / gallium arsenide; the double-junction solar cell includes, but is not limited to, a double-junction gallium indium phosphide / gallium arsenide or aluminum gallium indium phosphide / gallium arsenide; and the flexible triple-junction solar cell includes a triple-junction gallium indium phosphide / gallium arsenide / indium gallium arsenide. In the embodiments of the present application, to achieve a solar cell with higher photoelectric conversion efficiency, the solar cell is preferably a triple-junction, quad-junction, or multi-junction solar cell, so that the cell can absorb light in different wavelength bands.

[0051] In one embodiment of the present application, the flexible solar cell comprises a flexible triple-junction solar cell. Figure 4As shown, to obtain a flexible triple-junction solar cell, the solar cell epitaxial structure 3 includes a first ohmic contact layer 31, a GaInP top cell 32, a tunnel junction 33, a GaAs middle cell 34, a tunnel junction 35, an InGaAs bottom cell 36, and a second ohmic contact layer 37, which are sequentially stacked along a first direction. The first direction is perpendicular to the growth substrate 1 and points from the growth substrate 1 toward the solar cell epitaxial structure 3. Specifically, the GaInP top cell 32, the GaAs middle cell 34, and the InGaAs bottom cell 36 each include a window layer, an emitter region, a base region, and a back field layer, which are sequentially arranged along the first direction. The first ohmic contact layer 31 includes, but is not limited to, an N-type GaAs ohmic contact layer, and the second ohmic contact layer 37 includes, but is not limited to, a P-type InGaAs ohmic contact layer.

[0052] In the GaInP top cell 32, the back field layer includes an AlGaInP back field layer, the base region includes a P-type AlGaInP base region or a P-type GaInP base region, the emitter region includes an N-type AlGaInP emitter region or an N-type GaInP emitter region, and the window layer includes an AlInP window layer or an AlGaInP window layer; wherein, the N-type and P-type doping are obtained by doping with Si and C respectively; this application does not impose any restrictions on this.

[0053] In the tunnel junction (33 / 35), N-type GaAs or N-type GaInP is used as the N-type layer of the tunnel junction, and P-type (Al)GaAs material is used as the P-type layer of the tunnel junction; wherein the N-type and P-type doping are obtained by doping with Si and C respectively.

[0054] In the GaAs intermediate cell 34, the back field layer includes a GaInP back field layer, the base region includes a P-type GaAs base region, the emitter region includes an N-type GaAs emitter region, and the window layer includes a GaInP window layer; wherein the N-type and P-type doping are obtained by doping with Si and C respectively; this application does not impose any restrictions on this.

[0055] In the InGaAs bottom cell 36, the back field layer includes a GaInP or AlGaAs back field layer, the base region includes a P-type InGaAs base region, the emitter region includes an N-type InGaAs emitter region, and the window layer includes an AlGaInP or AlInP window layer; wherein, the N-type and P-type doping are obtained by doping with Si and C, respectively; this application does not impose any restrictions on this.

[0056] S03, such as Figure 5 As shown, a back electrode 4 is formed on the surface of the solar cell epitaxial structure 3 facing away from the growth substrate 1;

[0057] Specifically, in this step, Ti / Pt / Au is deposited on the surface of the solar cell epitaxial structure 3 by electron beam evaporation to form a back electrode 4; then, the back electrode 4 is rapidly annealed to form an ohmic contact with the solar cell epitaxial structure 3.

[0058] S04, such as Figure 6 As shown, a flexible substrate is fabricated on the surface of the back electrode 4, and the flexible substrate includes an alloy substrate formed by doping the metal film 5 body to improve the toughness of the metal film 5;

[0059] In one embodiment of the present application, the thermal expansion coefficient of the metal film 5 is greater than the thermal expansion coefficient of the dopant 6 .

[0060] In one embodiment of the present application, the difference between the thermal expansion coefficient of the metal film 5 and the thermal expansion coefficient of the dopant 6 is between 2×10 -6 / ℃ to 20×10 -6 / ℃, including the endpoint values.

[0061] In one embodiment of the present application, the Brinell hardness of the dopant 6 is between 60N / mm 2 ~200N / mm 2 Between, including the endpoint values.

[0062] In one embodiment of the present application, the metal film 5 provided in the embodiment of the present application includes but is not limited to one or more of a copper film, an aluminum film, and a titanium film. Accordingly, the alloy substrate includes a molybdenum-copper alloy substrate, a chromium-aluminum alloy substrate, or a titanium-germanium alloy substrate.

[0063] In one embodiment of the present application, the metal film 5 is doped by ion implantation or ion diffusion.

[0064] Specifically, a copper film is selected as the metal film 5, and its thickness is not greater than 50 μm; in this step, an ion implantation process can be used to implant molybdenum ions into the copper film, and the implantation depth is not greater than 50 μm to form a molybdenum-copper alloy substrate.

[0065] S05, such as Figure 7 As shown, the growth substrate 1 is peeled off to expose the front side of the solar cell epitaxial structure 3;

[0066] Specifically, in one embodiment of the present application, a solution containing ammonia water and hydrogen peroxide can be used to corrode and remove the growth substrate 1 (GaAs substrate); then, a hydrofluoric acid solution is used to remove the sacrificial layer, and a hydrochloric acid solution is used to remove the corrosion stop layer to expose the front side of the solar cell epitaxial structure 3.

[0067] S06, such as Figure 8 As shown, an electrode structure is fabricated on the front side of the solar cell, the electrode structure comprising a plurality of positive electrodes 7.1 and grid line electrodes 7.2 forming contacts;

[0068] In one embodiment of the present application, Figure 8 As shown, an anti-reflection film 8 is provided between two adjacent gate line electrodes 7.2.

[0069] In another embodiment of the present application, the anti-reflection film 8 covers the gate line electrode 7.2 and exposes at least a portion of the surface of the positive electrode 7.1.

[0070] Specifically, in this step, a photolithography process can be first used to form an electrode structure on the side of the first ohmic contact layer 31 facing away from the flexible substrate; wherein, the positive electrode 7.1 and the gate electrode 7.2 can be formed by electron beam evaporation. Optionally, the material of the positive electrode 7.1 provided in the embodiment of the present application can be one or more of Ti, Pd, Ag, Au, and AuGe. The gate electrode 7.2 includes a transparent electrode or a metal electrode; wherein, the transparent electrode includes one or more stacks of ITO electrodes, IZO electrodes, IGZO electrodes, AZO electrodes, and graphene electrodes; and the metal electrode includes one or more stacks of Ag electrodes, Au electrodes, Cu electrodes, and Au / Ag alloy electrodes.

[0071] Next, electron beam evaporation is used to deposit an anti-reflection film 8. The anti-reflection film 8 may be a single-layer structure or a multi-layer structure, and each layer may be made of TiO2, SiO2, MgF2 or Al2O3. The portion of the anti-reflection film 8 corresponding to the positive electrode 7.1 is then etched away.

[0072] S07. Separate the solar cells into a plurality of independent solar cells through a cutting process, so that each independent solar cell has a corresponding electrode structure. It should be noted that, in order to better illustrate the design key points of this application, the drawings in this application specification only illustrate a solar cell corresponding to a single electrode structure. However, the aforementioned steps of this application may include solar cells corresponding to multiple electrode structures.

[0073] Specifically, in this step, a diamond blade or a laser cutting machine is used to cut along the cutting path to obtain a plurality of independent solar cells.

[0074] Optionally, when a diamond blade is used for cutting in the embodiment of the present application, the exposed edge of the diamond blade is not less than 0.3 mm, and the cutting speed does not exceed 30 mm / s. This cutting process can ensure that the shrinkage of the flexible substrate is minimized, while taking into account high cutting quality and avoiding positive collapse.

[0075] When a laser cutting machine is used for cutting in the embodiment of the present application, the number of scribing passes of the laser cutting machine is 1-5, including the endpoint values, the cutting speed is 10mm / s-300mm / s, including the endpoint values, and the laser power is 1W-4W, including the endpoint values. On the premise of ensuring laser cutting through, the width of laser burning is taken into account to avoid leakage.

[0076] S08. Performing an alloying process on the electrode structure.

[0077] Preferably, the alloying process of the electrode structure is achieved by performing an annealing process in a nitrogen atmosphere.

[0078] Under a nitrogen atmosphere, annealing is performed at 250-400° C. for 20-30 minutes to ensure that the composition of the electrode structure 7 is uniform.

[0079] Through the above technical solution, it can be seen that the method for manufacturing a flexible solar cell provided by the present invention is to grow the solar cell epitaxial structure 3 in an inverted manner on the surface of the growth substrate 1; then, to form a back electrode 4 on the surface of the solar cell epitaxial structure 3 facing away from the growth substrate 1; and then, to form a flexible substrate on the surface of the back electrode 4, wherein the flexible substrate includes an alloy substrate formed by doping the metal film 5 to improve the toughness of the metal film 5. The flexible solar cell obtained based on this manufacturing method forms an alloy substrate by doping the metal film 5 to increase the toughness of the metal film 5, thereby supporting the compressive stress of the solar cell epitaxial structure 3 and maintaining the flatness of the wafer during the manufacturing process of the solar cell chip; thus, in the manufacturing process of the flexible solar cell, no temporary substrate / additional supporting substrate is required, and no bonding and debonding related processes are required, which reduces the demand for equipment and materials, thereby effectively reducing the production cost of the flexible solar cell.

[0080] Secondly, by setting the thermal expansion coefficient of the metal film 5 to be greater than the thermal expansion coefficient of the dopant 6, the thermal expansion coefficient of the alloy substrate is reduced, thereby reducing the difference in thermal expansion coefficients between the metal film 5 and the solar cell epitaxial structure 3, thereby reducing the compressive stress at the alloy contact surface between the solar cell epitaxial structure 3 and the flexible substrate during the alloy doping process of the metal film 5, so as to further avoid cracks in the solar cell epitaxial structure 3.

[0081] Then, in the manufacturing method of the present application, after completing the manufacturing of the front electrode (i.e., the electrode structure) of the flexible solar cell, by first cutting to form independent solar cell units and then implementing the alloy process of the electrode structure, it is beneficial to improve the problem of electrode damage caused by the cutting process (such as poor electrode contact, breakage, or even falling off).

[0082] Example 2

[0083] The embodiment of the present invention further provides a flexible solar cell manufactured by any of the above-mentioned methods for manufacturing a flexible solar cell. Figure 8 As shown, the flexible solar cell includes a back electrode 4, a solar cell epitaxial structure 3 and an electrode structure arranged in sequence on the surface of a flexible substrate, and the electrode structure includes a positive electrode 7.1 and a gate electrode 7.2 for forming contact; wherein, the flexible substrate includes an alloy substrate formed by doping a metal film 5 to improve the toughness of the metal film 5.

[0084] In one embodiment of the present application, the thermal expansion coefficient of the metal film 5 is greater than the thermal expansion coefficient of the dopant 6 .

[0085] In one embodiment of the present application, the difference between the thermal expansion coefficient of the metal film 5 and the thermal expansion coefficient of the dopant 6 is between 2×10 -6 / ℃ to 20×10 -6 / ℃, including the endpoint values.

[0086] In one embodiment of the present application, the thickness of the metal film 5 is no more than 100 μm.

[0087] In one embodiment of the present application, the Brinell hardness of the dopant 6 is between 60N / mm 2 ~200N / mm 2 Between, including the endpoint values.

[0088] In one embodiment of the present application, the doping concentration of the metal film 5 is 1*10 14 cm -3 ~1*10 19 cm -3 , including the endpoint values.

[0089] In one embodiment of the present application, the metal film 5 includes a stack of one or more of a copper film, an aluminum film, and a titanium film.

[0090] In one embodiment of the present application, the alloy substrate includes a molybdenum-copper alloy substrate, a chromium-aluminum alloy substrate, or a titanium-germanium alloy substrate.

[0091] In one embodiment of the present application, the gate line electrode 7.2 includes a transparent electrode or a metal electrode; wherein the transparent electrode includes a stack of one or more of an ITO electrode, an IZO electrode, an IGZO electrode, an AZO electrode, and a graphene electrode;

[0092] The metal electrode includes one or more stacks of Ag electrodes, Au electrodes, Cu electrodes, and Au / Ag alloy electrodes.

[0093] In one embodiment of the present application, an anti-reflection film 8 is provided between two adjacent gate line electrodes 7 . 2 .

[0094] In one embodiment of the present application, the anti-reflection film 8 covers the gate line electrode 7.2 and exposes at least a portion of the surface of the positive electrode 7.1.

[0095] In one embodiment of the present application, the flexible solar cell includes a flexible multi-junction solar cell or a flexible single-junction solar cell. The specific details of the solar cell epitaxial structure 3 can refer to the contents of Example 1, which will not be described in detail in this embodiment.

[0096] As can be seen from the above technical solution, the flexible solar cell provided in this embodiment includes a back electrode 4, a solar cell epitaxial structure 3, and an electrode structure, sequentially arranged on the surface of a flexible substrate. The electrode structure includes a positive electrode 7.1 and a gate electrode 7.2, which form a contact. The flexible substrate includes an alloy substrate formed by doping a metal film 5 to improve the toughness of the flexible substrate. Based on this structural arrangement, the alloy substrate is formed by doping the metal film 5 to increase the toughness of the metal film 5, thereby supporting the compressive stress of the solar cell epitaxial structure 3 and maintaining the flatness of the solar cell chip during the manufacturing process. As such, the flexible solar cell provided by this utility model does not require a temporary substrate or additional support substrate, nor does it require bonding and debonding processes, reducing the equipment and material requirements, thereby effectively reducing the production cost of the flexible solar cell.

[0097] Secondly, by setting the thermal expansion coefficient of the metal film 5 to be greater than the thermal expansion coefficient of the dopant 6, the thermal expansion coefficient of the alloy substrate is reduced, thereby reducing the difference in thermal expansion coefficients between the metal film 5 and the solar cell epitaxial structure 3, thereby reducing the compressive stress at the alloy contact surface between the solar cell epitaxial structure 3 and the flexible substrate during the alloy doping process of the metal film 5, so as to further avoid cracks in the solar cell epitaxial structure 3.

[0098] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0099] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such article or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the article or device comprising the aforementioned elements.

[0100] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flexible solar cell, characterized in that: The invention comprises a back electrode, a solar cell epitaxial structure and an electrode structure sequentially arranged on the surface of a flexible substrate, wherein the electrode structure comprises a positive electrode and a gate electrode for forming a contact; wherein the flexible substrate comprises an alloy substrate formed by doping a metal film; Wherein, the metal film includes a stack of one or more of a copper film, an aluminum film, and a titanium film; The alloy substrate includes a molybdenum-copper alloy substrate, a chromium-aluminum alloy substrate, or a titanium-germanium alloy substrate.

2. The flexible solar cell according to claim 1, characterized in that The gate line electrode includes a transparent electrode or a metal electrode; Wherein, the transparent electrode comprises a stack of one or more of an ITO electrode, an IZO electrode, an IGZO electrode, an AZO electrode and a graphene electrode; The metal electrode includes one or more stacks of Ag electrodes, Au electrodes, Cu electrodes, and Au / Ag alloy electrodes.

3. The flexible solar cell according to claim 1, characterized in that An anti-reflection film is provided between two adjacent gate line electrodes.

4. The flexible solar cell according to any one of claims 1 to 3, characterized in that: The flexible solar cell includes a flexible multi-junction solar cell or a flexible single-junction solar cell.

5. The flexible solar cell according to claim 4, characterized in that: The flexible solar cell includes a flexible triple-junction solar cell, and the solar cell epitaxial structure includes a bottom cell, a tunnel junction, an intermediate cell, a tunnel junction and a top cell stacked in sequence on the back electrode surface.

6. The flexible solar cell according to claim 4, characterized in that: The flexible solar cell includes a flexible double-junction solar cell, and the solar cell epitaxial structure includes a bottom cell, a tunnel junction, and a top cell stacked in sequence on the surface of the back electrode.

Images