Preparation method of solar cell, heterojunction solar cell and photovoltaic module

Abstract

The invention is suitable for the technical field of solar cell preparation, and provides a preparation method of a solar cell, a heterojunction solar cell and a photovoltaic module, and the preparation method of the solar cell comprises the steps: preparing a mask on an oxide thin film of the solar cell through an ink-jet printing ink film making mode, the width of the wire slot is smaller than a preset width threshold; etching the part, corresponding to the wire slot, of the oxide thin film to form a groove which does not penetrate through the oxide thin film; and preparing a metal electrode in the groove. The mask is prepared through ink-jet printing, so that the width of the wire slot of the mask is smaller than the preset width threshold, and therefore, a thinner metal electrode can be subsequently prepared, the line width of the metal electrode can be reduced, the shading ratio can be reduced, the shading area of a cell can be reduced, the short-circuit current can be improved, and the photoelectric conversion efficiency can be further improved; in addition, the metal electrode is embedded in the groove, so that the sheet resistance of the oxide film is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cell preparation, and in particular relates to a method for preparing a solar cell, a heterojunction solar cell and a photovoltaic module. Background Art

[0002] Solar cells usually need to be equipped with a grid structure, such as HJT (heterojunction solar cell, heterojunction solar cell) cells, whose PN junction is composed of amorphous silicon (α-Si) and crystalline silicon (c-Si), where amorphous silicon includes intrinsic amorphous silicon (i-type) and doped amorphous silicon (p, n-type). The current conventional process for preparing HJT cells is: depositing an intrinsic amorphous silicon film and a doped amorphous silicon film with opposite polarity on both sides of the silicon wafer, then depositing a transparent conductive oxide film (transparent conductive oxide, TCO), and finally printing a grid structure on the TCO layer (transparent conductive film) on the surface of the cell.

[0003] The grid line structure includes a main grid line and a secondary grid line, wherein the secondary grid line guides the current generated by the semiconductor material through the photovoltaic effect, and the main grid line collects the current on each secondary grid line and transmits it through the welding strip welded thereon.

[0004] The existing HJT battery preparation process usually uses screen printing to directly print slurry on TCO to form a grid line structure. The grid line width is wide and the square resistance is large. In addition, the grid line on the front of the battery has a large shading area, which affects the collection of current and reduces the photoelectric conversion efficiency of the battery. Summary of the invention

[0005] The embodiment of the present invention provides a method for preparing a solar cell, aiming to solve the problem that the existing solar cell adopts a screen printing method to form a grid line structure, and has large square resistance and large light shielding area.

[0006] The embodiment of the present invention is implemented as follows: a method for preparing a solar cell, comprising:

[0007] A mask is prepared on an oxide film of a solar cell by inkjet printing ink film-making, wherein the solar cell has a front side and a back side opposite to each other, an oxide film is arranged on the front side and / or the back side, and a mask is arranged on the oxide film of at least one of the front side and the back side, and the mask has a plurality of parallel line grooves, and the width of the line grooves is less than a preset width threshold;

[0008] Etching the portion of the oxide film corresponding to the wire groove to form a groove that does not penetrate the oxide film;

[0009] Metal electrodes are prepared in the grooves.

[0010] Furthermore, the preset width threshold is less than 1.2 mm.

[0011] Further, the metal electrode extends out of the groove, and the distance between the portion of the metal electrode extending out of the groove and the opening of the groove is 0.05 μm to 2 μm.

[0012] Furthermore, the metal electrode includes a first electrode located on the front side of the solar cell and a second electrode located on the back side of the solar cell, and the first electrode and / or the second electrode are made by metal evaporation or metal electroplating.

[0013] Furthermore, the vacuum degree of the metal deposition method is 5×10 -5 Pa to 2×10 -4 Pa, the evaporation temperature is 500℃ to 2000℃, and the evaporation rate is to

[0014] Furthermore, after the step of preparing the metal electrode in the groove, the method further comprises:

[0015] A layer of low-temperature metal paste is printed on the basis of the metal electrode.

[0016] Furthermore, before the step of preparing a mask on the oxide film of the solar cell by inkjet printing ink film formation, the method further comprises:

[0017] Prepare a first intrinsic amorphous silicon layer and a second intrinsic amorphous silicon layer on the front side and the back side of the silicon substrate respectively;

[0018] On the basis of the first intrinsic amorphous silicon layer and the second intrinsic amorphous silicon layer, a first doped amorphous silicon layer and a second doped amorphous silicon layer are respectively prepared;

[0019] An oxide film is prepared on the basis of the first doped amorphous silicon layer and the second doped amorphous silicon layer.

[0020] Furthermore, the front side and / or the back side of the silicon substrate is textured or smooth.

[0021] In a second aspect, the present application further provides a heterojunction solar cell, which is manufactured using the above-mentioned solar cell manufacturing method.

[0022] In a third aspect, the present application also provides a photovoltaic module, comprising the heterojunction solar cell as described above.

[0023] The beneficial effect of the present application is that the method for preparing a solar cell of the present application includes preparing a mask on an oxide film of a solar cell by means of inkjet printing ink film making, wherein the solar cell has a relative front and back side, an oxide film is arranged on the front side and / or the back side, a mask is arranged on the oxide film of at least one of the front side and the back side, the mask has a plurality of parallel wire grooves, and the width of the wire grooves is less than a preset width threshold; etching the portion of the oxide film corresponding to the wire grooves to form a groove that does not penetrate the oxide film; and preparing a metal electrode in the groove. The mask is prepared by inkjet printing ink, so that the width of the wire groove of the mask is less than the preset width threshold, so that a thinner metal electrode can be prepared in the subsequent preparation, the line width of the metal electrode is reduced, the shading ratio is reduced, the shading area of ​​the cell is reduced, the short-circuit current is increased, and the photoelectric conversion efficiency is further improved; in addition, the metal electrode is embedded in the groove to reduce the square resistance of the oxide film. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a process of an embodiment of a method for preparing a solar cell provided in the present application;

[0025] Figure 2 This is a schematic diagram of a process of printing a low-temperature metal paste in one embodiment of a method for preparing a solar cell provided in the present application;

[0026] Figure 3 is a schematic flow chart of another embodiment of the method for preparing a solar cell provided in the present application;

[0027] Figure 4 This is a schematic diagram of a film structure of a mask disposed on the front side of a solar cell in one embodiment of a method for preparing a solar cell provided by the present application;

[0028] Figure 5 This is a schematic diagram of the film layer structure of preparing grooves in a front oxide film in one embodiment of the method for preparing a solar cell provided by the present application;

[0029] Figure 6 It is a schematic structural diagram of removing the front mask in one embodiment of the method for preparing a solar cell provided by the present application;

[0030] Figure 7 It is a schematic structural diagram of preparing a front electrode in a groove of a front oxide film according to an embodiment of a method for preparing a solar cell provided by the present application;

[0031] Figure 8 It is a schematic structural diagram of printing a low-temperature metal paste on a front electrode in one embodiment of a method for preparing a solar cell provided in the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be construed as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] In the description of the present invention, it is necessary to understand that the terms "length", "width", "up", "down", "left", "right", "horizontal", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0037] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the examples of various specific processes and materials provided by the present invention, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0038] The method for preparing a solar cell of the present application includes preparing a mask on an oxide film of a solar cell by means of inkjet printing ink film making, wherein the solar cell has a relative front and back side, an oxide film is arranged on the front side and / or the back side, a mask is arranged on the oxide film of at least one of the front side and the back side, the mask has a plurality of parallel wire grooves, and the width of the wire grooves is less than a preset width threshold; etching the portion of the oxide film corresponding to the wire grooves to form a groove that does not penetrate the oxide film; and preparing a metal electrode in the groove. The mask is prepared by inkjet printing ink, so that the width of the wire groove of the mask is less than the preset width threshold, so that a thinner metal electrode can be prepared in the subsequent preparation, the line width of the metal electrode is reduced, the shading ratio is reduced, the shading area of ​​the cell is reduced, the short-circuit current is increased, and the photoelectric conversion efficiency is further improved; in addition, the metal electrode is embedded in the groove to reduce the square resistance of the oxide film.

[0039] Embodiment 1

[0040] like Figures 1 to 8 As shown, one embodiment of the present application provides a method for preparing a solar cell, comprising:

[0041] S1100, preparing a mask 800 on an oxide film of a solar cell by inkjet printing ink film-making, wherein the solar cell has a front side and a back side opposite to each other, an oxide film is disposed on the front side and / or the back side, and the mask 800 is disposed on the oxide film of at least one of the front side and the back side, and the mask 800 has a plurality of parallel line grooves 630, and the width of the line grooves 630 is less than a preset width threshold;

[0042] S1200, etching the portion of the oxide film corresponding to the line groove 630 to form a groove 410 that does not penetrate the oxide film;

[0043] S1300 , preparing a metal electrode in the groove 410 .

[0044] The solar cell is provided with an oxide film, namely TCO (Transparent conducting oxide). TCO is a transparent conductive oxide film uniformly coated on a target position (such as a glass surface) by physical or chemical coating methods to collect current.

[0045] In implementation, TCO mainly includes oxides of In (indium), Sn (tin), Zn (zinc) and Cd (cadmium) and their composite multi-oxide thin film materials. For example, the TCO layer can use IZO (indium zinc oxide), ITO (tin-doped indium oxide), IWO (tungsten-doped indium oxide) or IZrO (zirconium-doped indium oxide), etc., without limitation.

[0046] The oxide film may be disposed on the front side of the solar cell, or the oxide film may be disposed on the back side of the solar cell, or the oxide film may be disposed on both the front side and the back side of the solar cell.

[0047] Optionally, the front and back sides of the solar cell are two opposite sides. Usually, the front side of the solar cell is regarded as the light-receiving side, and the back side of the solar cell is regarded as the backlight side, without limitation.

[0048] In some embodiments, when an oxide film is provided on the front side of the solar cell, the oxide film provided on the front side of the solar cell may be provided with a mask 800. Similarly, when an oxide film is provided on the back side of the solar cell, the oxide film provided on the back side of the solar cell may be provided with a mask 800. Alternatively, when an oxide film is provided on both the front side and the back side of the solar cell, the oxide film on the front side and / or the oxide film on the back side may be provided with a mask 800, without limitation.

[0049] The main function of the mask 800 is to cover the non-etched part, that is, the mask 800 covers the part of the solar cell that does not need to be etched, and exposes the part that needs to be etched, so that the exposed part can be etched away during the subsequent acid etching or alkaline etching to form a specific figure or pattern.

[0050] The mask 800 of the present application is made by inkjet printing ink film making. In practice, the inkjet printing ink film making method refers to spraying ink to a specified position by inkjet to generate a mask 800 with a specific pattern structure. In some embodiments, ink can be directly sprayed on a solar cell by inkjet printing ink film making to form the mask 800. As a possible method, ink can also be sprayed on a printing plate to support the finished mask 800 by inkjet printing ink film making, and then the finished mask 800 is attached to the solar cell for subsequent steps.

[0051] In implementation, the width of the line groove 630 is less than the preset width threshold. Since the inkjet printing ink film-making method can achieve an inkjet printing line width of 10μm to 60μm, the mask 800 made by the inkjet printing ink film-making method can achieve a line groove 630 width of 0 to 1.2mm, that is, the preset width threshold is less than 1.2mm. In addition, the inkjet printed graphics can be adjusted at any time without the need for screen customization, which is easy to use and saves procedures and costs.

[0052] The wire groove 630 is used for subsequent printing to prepare the metal electrode. For example, taking the metal electrode as the main grid, the width of the wire groove 630 can be designed to be 0-1.2mm. For example, the width of the wire groove 630 can be 0.01mm, 0.02mm, 0.03mm, 0.1mm, 0.5mm, 0.8mm, 1.0mm or any value in the range of 0-1.2mm, without limitation.

[0053] It should be noted that when the width of the wire slot 630 is 0, it indicates that there is no main grid.

[0054] As a possible implementation, when the metal electrode is a secondary gate line, the width of the line groove 630 can be designed to be 10μm to 20μm, for example, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm or any value between 10μm and 20μm, without limitation.

[0055] After setting the mask 800, the portion of the oxide film corresponding to the line groove 630 can be etched, that is, the portion of the oxide film covered with the mask 800 is not etched, while the portion not covered by the mask 800 (the line groove 630 portion) is etched to form a groove 410, which does not penetrate the oxide film.

[0056] Optionally, the etching of the oxide film covering can be carried out by acid solution etching, for example, by etching with HCL (hydrogen chloride, whose aqueous solution is hydrochloric acid) / HF (hydrogen fluoride, whose aqueous solution is hydrofluoric acid) / HNO3 (nitric acid) to form the groove 410. During implementation, the etching depth of the oxide film can be controlled by controlling the concentration of the acid solution and the time of the acid etching, so as to avoid etching through the oxide film while forming the groove 410.

[0057] After the groove 410 is prepared, a metal electrode may be prepared in the groove 410 . Usually, the metal electrode may be prepared by printing a metal paste.

[0058] As a possible implementation, the metal electrode may also be prepared by metal evaporation, without limitation.

[0059] Optionally, the metal electrode includes one or a combination of silver, tin, zinc, copper and other metals with conductive properties, without limitation.

[0060] The metal electrode includes a first electrode and a second electrode, wherein the first electrode is located on the front side of the solar cell and the second electrode is located on the back side of the solar cell. The polarities of the first electrode and the second electrode are opposite, for example, when the first electrode is positive, the second electrode is negative; similarly, when the first electrode is negative, the second electrode is positive.

[0061] The first electrode can be made by metal evaporation or metal electroplating, and similarly, the second electrode can also be made by metal evaporation or metal electroplating, without limitation.

[0062] In practice, evaporation is to convert solid substances into gaseous state by heating, and then let the gaseous substances enter a vacuum or inert gas container, and form metal electrodes in the groove 410 through the collision between substances. Exemplarily, the evaporation vacuum degree of the metal evaporation method is 5×10^(-5)Pa to 2×10^(-4)Pa, the evaporation temperature is 500℃ to 2000℃, and the evaporation rate is to For example, when the metal electrode is silver, the deposition is performed on the mask 800, the deposition vacuum is 5×10^(-5)Pa to 2×10^(-4)Pa, the deposition temperature is 500°C to 2000°C, and the evaporation rate is to The thickness of the fabricated metal electrode is 100-120 nm.

[0063] Electroplating is to place a metal compound into an electrolyte and apply current to cause an electrochemical reaction. The metal ions are deposited in the groove 410 under the action of electrochemical reduction to form a metal electrode.

[0064] The method for preparing a solar cell of the present application includes preparing a mask 800 on an oxide film of a solar cell by means of inkjet printing ink film making, wherein the solar cell has a relative front and back side, an oxide film is arranged on the front side and / or the back side, and a mask 800 is arranged on the oxide film of at least one of the front side and the back side, and the mask 800 has a plurality of parallel line grooves 630, and the width of the line grooves 630 is less than a preset width threshold; etching the portion of the oxide film corresponding to the line grooves 630 to form a groove 410 that does not penetrate the oxide film; and preparing a metal electrode in the groove 410. The mask 800 is prepared by inkjet printing ink, so that the width of the line grooves 630 of the mask 800 is less than the preset width threshold, so that a thinner metal electrode can be prepared in the subsequent preparation, the line width of the metal electrode is reduced, the shading ratio is reduced, the shading area of ​​the cell is reduced, the short-circuit current is increased, and the photoelectric conversion efficiency is further improved; in addition, the metal electrode is embedded in the groove 410 to reduce the square resistance of the oxide film.

[0065] In some optional embodiments, the metal electrode partially extends out of the groove 410, and the distance between the end of the metal electrode extending beyond the groove 410 and the opening of the groove 410 is 0.05μm to 2μm. For example, the distance between the end and the opening is 0.06μm, 0.08μm, 0.09μm, 0.1μm, 0.2μm, 0.4μm, 0.5μm, 0.8μm or any value between 0.05μm and 2μm, without limitation.

[0066] During implementation, the metal electrode can be a main grid line or a secondary grid line. The secondary grid line needs to be connected to the main grid line, and the main grid line is connected to the welding strip or bus bar to aggregate the current of the secondary grid line to the main grid line, and then the main grid line flows to the welding strip or bus bar. Of course, when there is no main grid line, the current can be directly aggregated to the welding strip or bus bar by the secondary grid line. The part of the metal electrode that exceeds the groove 410 is convenient for welding and connection with other grid lines, welding strips or bus bars. At the same time, since the metal electrode is 0.05μm to 2μm higher than the opening of the groove 410, the height of the metal electrode is moderate, which reduces the shading ratio while reducing the lateral parasitic absorption of TCO and reducing the series resistance.

[0067] In some optional embodiments, such as Figure 2 As shown, after the step of preparing the metal electrode in the groove 410, the method for preparing the solar cell provided by the present application further includes:

[0068] S1400, printing a layer of low-temperature metal paste 900 on the basis of the metal electrode.

[0069] During implementation, the low-temperature metal paste 900 includes one or a combination of silver, tin, zinc, copper, and other metals having conductive properties, without limitation.

[0070] Optionally, a low-temperature metal slurry 900 can be prepared by screen printing on the basis of the metal electrode through a low-thickness screen to cover the metal electrode. On the one hand, the series resistance can be reduced. On the other hand, the metal electrode made by evaporating metal does not need to be too large, which reduces the loss of evaporated metal slurry and controls costs.

[0071] In some optional embodiments, such as Figure 3 As shown, before the step of preparing a mask 800 on the oxide film of the solar cell by inkjet printing ink film formation, the method for preparing a solar cell provided by the present application further includes:

[0072] S1010, preparing a first intrinsic amorphous silicon layer 200 and a second intrinsic amorphous silicon layer 300 on the front side and the back side of the silicon substrate 100 respectively;

[0073] S1020, preparing a first doped amorphous silicon layer 400 and a second doped amorphous silicon layer 500 on the basis of the first intrinsic amorphous silicon layer 200 and the second intrinsic amorphous silicon layer 300 respectively;

[0074] S1030 , preparing an oxide film on the basis of the first doped amorphous silicon layer 400 and the second doped amorphous silicon layer 500 .

[0075] The solar cell includes a silicon substrate 100, a first intrinsic amorphous silicon layer 200, a second intrinsic amorphous silicon layer 300, a first doped amorphous silicon layer 400 and a second doped amorphous silicon layer 500, wherein the silicon substrate 100 includes single crystal silicon and polycrystalline silicon. Typically, the silicon substrate 100 can be a p-type silicon wafer or an n-type silicon wafer without limitation.

[0076] Optionally, the silicon substrate 100 has a front side and a back side, wherein the front side of the silicon substrate 100 is the front side of the solar cell, and the back side of the silicon substrate 100 is the back side of the solar cell. The front side and / or back side of the silicon substrate 100 may be a velvet surface or a smooth surface, without limitation.

[0077] For example, taking an n-type silicon wafer as an example, a first intrinsic amorphous silicon layer 200 and a first doped amorphous silicon layer 400 are deposited on the front side of a silicon substrate 100, and the first doped amorphous silicon layer 400 is a p-type amorphous silicon thin film, thereby forming a PN junction. A second intrinsic amorphous silicon layer 300 and a second doped amorphous silicon layer 500 are deposited on the back side of the silicon substrate 100, and the second doped amorphous silicon layer 500 is an n-type amorphous silicon thin film, thereby forming a back surface field.

[0078] Since oxide films are disposed on both the first doped amorphous silicon layer 400 and the second doped amorphous silicon layer 500 , the oxide film disposed on the first doped amorphous silicon layer 400 can be regarded as the front oxide film 610 , and the oxide film disposed on the second doped amorphous silicon layer 500 can be regarded as the back oxide film 620 .

[0079] The front oxide film 610 and / or the back oxide film 620 are provided with a mask 800 to form a groove 410 on the front oxide film 610 and / or the back oxide film 620 , and then a metal electrode is prepared in the groove 410 .

[0080] In some embodiments, taking the groove 410 provided on the back oxide film 620 as an example, the metal electrode formed in the groove 410 of the back oxide film 620 is the back electrode 710, which can effectively reduce the square resistance of the back oxide film 620. In this case, the front oxide film 610 may not be provided with the groove 410, that is, the metal paste is directly printed on the surface of the front oxide film 610 to form the front electrode 720.

[0081] As a possible implementation, taking the groove 410 provided on the front oxide film 610 as an example, the metal electrode made in the groove 410 of the front oxide film 610 is the front electrode 720, which can effectively reduce the square resistance of the front oxide film 610. At the same time, since the front electrode 720 is made thinner, the light shielding area of ​​the front electrode 720 is reduced, and the photoelectric conversion efficiency is improved. In this case, the back oxide film 620 may not be provided with the groove 410, that is, the metal paste is directly printed on the surface of the back oxide film 620 to form the back electrode 710.

[0082] In some possible embodiments, taking the case where both the front oxide film 610 and the back oxide film 620 are provided with grooves 410, the metal electrode made in the grooves 410 of the front oxide film 610 is the front electrode 720, and the metal electrode made in the grooves 410 of the back oxide film 620 is the back electrode 710. Since the front electrode 720 is made thinner, the shading area of ​​the front electrode 720 is reduced, and the photoelectric conversion efficiency is improved. At the same time, the square resistance of the front oxide film 610 and the back oxide film 620 is reduced, taking into account the effects of low shading ratio and low square resistance.

[0083] In some embodiments, for example, the mask 800 is only provided on the front side. Figures 4 to 8 As shown, the solar cell preparation process is as follows:

[0084] An n-type silicon wafer is selected as the silicon substrate 100 , and the thickness of the silicon substrate 100 is 70 μm to 200 μm (micrometers) and the resistivity is 0-9 Ω·cm-1.

[0085] The first intrinsic amorphous silicon layer 200 and the second intrinsic amorphous silicon layer 300 are prepared. The thickness of the first intrinsic amorphous silicon layer 200 and the second intrinsic amorphous silicon layer 300 is 3nm-10nm (nanometer). The deposition gas in the preparation process is [SiH]_4 (monosilane), the temperature is 200°C-260°C, the gas flow rate is 800sccm-3000sccm (standard cubic centimeter per minute, standard cubic centimeter per minute), and the deposition rate is (Angstroms / second), the time is 5s-30s (seconds). During the deposition process, the working gas (〖SiH〗_4) is discharged at high voltage, and the gas decomposes to generate a mixture of ions and active groups, which grow on the surface to form an amorphous silicon thin film layer.

[0086] A first doped amorphous silicon layer 400 and a second doped amorphous silicon layer 500 are prepared. The thickness of the first doped amorphous silicon layer 400 and the second doped amorphous silicon layer 500 is 15nm-20nm. The deposited gas is a mixture of a doping source gas and hydrogen. The doping concentration is 1%-5%, the temperature is 200℃-250℃, and the gas flow rate is 800sccm-3000sccm.

[0087] A front oxide film 610 and a back oxide film 620 are prepared, the thickness of the front oxide film 610 and the back oxide film 620 is 80nm-120nm, the deposition working pressure is 2x10^3Pa-10x10^3Pa, the protective gas is argon, and the sputtering power is 60W-100W.

[0088] Prepare the back electrode 710, cover the silver electrode on the back side of the back oxide film 620 (the side away from the silicon substrate 100) by screen printing, and then cure it at 130°C to 250°C; the silver electrode is formed by vertically distributing the main grid and the sub-grid, the number of main grid lines is 0-20, the width of the main grid line is 0-1.2mm, the number of sub-grid lines is 100-250, and the width of the sub-grid lines is 20μm-60μm.

[0089] Prepare a front mask 800 by inkjet printing ink film formation on the front oxide film 610, with a nozzle diameter of 10μm-60μm, an ink viscosity of 10mPa·s-80mPa·s (milliPascal·second), a surface tension of 20mN / m-100mN / m, and a particle size of 50μm-200μm.

[0090] After preparing the front mask 800, the front oxide film 610 is corroded by acid at the position of the line groove 630 of the mask 800 to form a groove 410. The etching depth of the front oxide film 610 is controlled by controlling the concentration and time of the acid. For example, the concentration of the acid is 5%-30%, and the time is 5min-10min, so that the remaining thickness of the front oxide film 610 corresponding to the groove 410 is 20nm-30nm.

[0091] The front electrode 720 is prepared by evaporation on the front mask 800. Taking the evaporation metal paste as evaporation silver as an example, the evaporation vacuum is 5x10^(-5)Pa~2x10^(-4)Pa, the evaporation temperature is 500℃~2000℃, and the evaporation rate is The thickness of the metal electrode deposited is 100nm-120nm.

[0092] Printing low-temperature metal paste 900, taking low-temperature metal paste 900 as low-temperature silver paste as an example, that is, using a low-thickness screen on the top of the front metal, screen printing is used to cover it, the curing temperature is 130°C ~ 250°C, and the evaporated silver and low-temperature silver paste form a silver electrode. The silver electrode is formed by vertically distributing a main grid and a sub-grid. The number of main grid lines is 0-20, and the width of the main grid line is 0-0.04mm. The number of sub-grid lines is 80-150, and the width of the sub-grid line is 10μm-20μm. The printing pressure is 40N-60N, the screen spacing is 0.5mm-2.5mm, the scraper hardness is 60A-70A, and the printing speed is 100mm / s ~ 400mm / s.

[0093] Embodiment 2

[0094] In some optional embodiments, the present application provides a heterojunction solar cell, which is manufactured using the above-mentioned solar cell manufacturing method.

[0095] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the structure and implementation principle of the heterojunction solar cell described above can refer to the corresponding structure and implementation principle in the aforementioned embodiment 1, and will not be repeated here.

[0096] The method for preparing a solar cell of the present application includes preparing a mask 800 on an oxide film of a solar cell by means of inkjet printing ink film making, wherein the solar cell has a relative front and back side, an oxide film is arranged on the front side and / or the back side, and a mask 800 is arranged on the oxide film of at least one of the front side and the back side, and the mask 800 has a plurality of parallel line grooves 630, and the width of the line grooves 630 is less than a preset width threshold; etching the portion of the oxide film corresponding to the line grooves 630 to form a groove 410 that does not penetrate the oxide film; and preparing a metal electrode in the groove 410. The mask 800 is prepared by inkjet printing ink, so that the width of the line grooves 630 of the mask 800 is less than the preset width threshold, so that a thinner metal electrode can be prepared in the subsequent preparation, the line width of the metal electrode is reduced, the shading ratio is reduced, the shading area of ​​the cell is reduced, the short-circuit current is increased, and the photoelectric conversion efficiency is further improved; in addition, the metal electrode is embedded in the groove 410 to reduce the square resistance of the oxide film.

[0097] Embodiment 3

[0098] In some optional embodiments, the present application provides a photovoltaic module, including the heterojunction solar cell as described above.

[0099] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the structure and implementation principle of the photovoltaic assembly described above can refer to the corresponding structure and implementation principle in the aforementioned embodiments one and two, and will not be repeated here.

[0100] The method for preparing a solar cell of the present application includes preparing a mask 800 on an oxide film of a solar cell by means of inkjet printing ink film making, wherein the solar cell has a relative front and back side, an oxide film is arranged on the front side and / or the back side, and a mask 800 is arranged on the oxide film of at least one of the front side and the back side, and the mask 800 has a plurality of parallel line grooves 630, and the width of the line grooves 630 is less than a preset width threshold; etching the portion of the oxide film corresponding to the line grooves 630 to form a groove 410 that does not penetrate the oxide film; and preparing a metal electrode in the groove 410. The mask 800 is prepared by inkjet printing ink, so that the width of the line grooves 630 of the mask 800 is less than the preset width threshold, so that a thinner metal electrode can be prepared in the subsequent preparation, the line width of the metal electrode is reduced, the shading ratio is reduced, the shading area of ​​the cell is reduced, the short-circuit current is increased, and the photoelectric conversion efficiency is further improved; in addition, the metal electrode is embedded in the groove 410 to reduce the square resistance of the oxide film.

[0101] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a solar cell, characterized in that: include: A mask is prepared on an oxide film of a solar cell by inkjet printing ink film-making, wherein the solar cell has a front side and a back side opposite to each other, the front side and / or the back side are provided with the oxide film, the mask is provided on the oxide film of at least one of the front side and the back side, the mask has a plurality of parallel line grooves, and the width of the line grooves is less than a preset width threshold; Etching a portion of the oxide film corresponding to the wire groove to form a groove that does not penetrate the oxide film; A metal electrode is prepared in the groove.

2. The method for preparing a solar cell according to claim 1, characterized in that: The preset width threshold is less than 1.2 mm.

3. The method for preparing a solar cell according to any one of claims 1 to 2, characterized in that: The metal electrode extends out of the groove, and a distance between a portion of the metal electrode extending out of the groove and an opening of the groove is 0.05 μm to 2 μm.

4. The method for preparing a solar cell according to claim 1, wherein: The metal electrode includes a first electrode located on the front side of the solar cell and a second electrode located on the back side of the solar cell. The first electrode and / or the second electrode are made by metal evaporation or metal electroplating.

5. The method for preparing a solar cell according to claim 4, characterized in that: The vacuum degree of the metal evaporation method is 5×10 -5 Pa to 2×10 -4 Pa, the evaporation temperature is 500℃ to 2000℃, and the evaporation rate is to 6. The method for preparing a solar cell according to claim 1, characterized in that: After the step of preparing the metal electrode in the groove, the method further comprises: A layer of low-temperature metal paste is printed on the basis of the metal electrode.

7. The method for preparing a solar cell according to claim 1, characterized in that: Before the step of preparing a mask on the oxide film of the solar cell by inkjet printing ink film forming, the method further comprises: Prepare a first intrinsic amorphous silicon layer and a second intrinsic amorphous silicon layer on the front side and the back side of the silicon substrate respectively; On the basis of the first intrinsic amorphous silicon layer and the second intrinsic amorphous silicon layer, respectively prepare a first doped amorphous silicon layer and a second doped amorphous silicon layer; The oxide film is prepared on the basis of the first doped amorphous silicon layer and the second doped amorphous silicon layer.

8. The method for preparing a solar cell according to claim 7, characterized in that: The front side and / or the back side of the silicon substrate is textured or smooth.

9. A heterojunction solar cell, characterized in that: The heterojunction solar cell is manufactured by the method for manufacturing a solar cell according to any one of claims 1 to 8.

10. A photovoltaic module, characterized in that: Comprising the heterojunction solar cell as claimed in claim 9.

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