Solar cell and electric jet printing method of solar cell grid line

Abstract

The invention relates to the technical field of solar cells, in particular to a solar cell and an electric jet printing method of solar cell grid lines. The electric jet printing method for the solar cell grid line comprises the following steps that a spray head and an objective table which are oppositely arranged are provided, and a nozzle is arranged at an outlet of the spray head; taking a battery piece to be subjected to electric jet printing as a substrate, and fixing the substrate on an objective table; the slurry is introduced into a spray head, voltage is applied between the spray head and an objective table, so that the slurry in the spray head forms a Taylor cone at a spray nozzle, and the Taylor cone is attached to the substrate under the action of the voltage; meanwhile, according to the shape of the grid line pattern, the nozzle and the substrate are controlled to generate relative motion so as to carry out electric jet printing according to the shape of the grid line pattern; and after the electric jet printing operation is completed, processing the slurry on the substrate to remove the solvent and form the grid line. According to the embodiment of the invention, a pattern which is smaller than the size of a nozzle by one order of magnitude can be printed, and the printing resolution is higher.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to an electrospray printing method for a solar cell and a solar cell grid line. Background Art

[0002] In order to achieve a continuous decline in the cost of photovoltaic power, the single-watt precious metal consumption of electrodes / grids in monolithic cells needs to be continuously reduced. Reducing the thickness of the electrode (grid) can reduce the electrode metal. At present, the electrodes in solar cells are usually made by screen printing. However, as the electrode grid gradually decreases, the electrode grid gradually approaches the accuracy and resolution limit of screen printing. Improvements based on screen printing technology can no longer meet the goal of further reducing the grid size.

[0003] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the invention

[0004] The embodiments of the present application provide a solar cell and a method for electrospraying a solar cell grid line to solve or alleviate one or more of the technical problems mentioned above.

[0005] A first aspect of an embodiment of the present application provides an electrospray printing method for solar cell grid lines.

[0006] Providing a nozzle and a stage that are arranged opposite to each other, wherein the nozzle is provided at an outlet of the nozzle; The battery sheet to be electrosprayed is used as a substrate and fixed on the stage; Performing an electrospray printing operation: passing the slurry into the nozzle, applying a voltage between the nozzle and the stage, so that the slurry in the nozzle forms a Taylor cone at the nozzle, and the Taylor cone adheres to the substrate under the action of the voltage; at the same time, according to the shape of the grid line pattern, controlling the relative movement between the nozzle and the substrate, so as to perform electrospray printing on the substrate according to the shape of the grid line pattern; After the electrospray printing operation is completed, the slurry on the substrate is treated to remove the solvent and form grid lines.

[0007] In the first aspect of the embodiment of the present application, the slurry is printed on the substrate by electrospray printing to form a preset grid line pattern. Since the driving force is an electric field, the slurry will form a Taylor cone at the nozzle under the drive of the electric field. Therefore, a pattern with a size one order of magnitude smaller than the nozzle size can be printed, with a higher printing resolution. Similarly, since the printing driving force is an electrical signal, which is easier to control than air pressure, this technology can also print more complex patterns than capillary printing.

[0008] The second aspect of the embodiment of the present application provides a solar cell grid line, comprising the grid line prepared by the electrospray printing method of the first aspect, so that the size of the grid line can be made smaller and finer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application.

[0010] Figure 1 is a schematic diagram of the structure of the electrospray printing device provided in an embodiment of the present application; Figure 2 It is a schematic diagram of the structure of the TOPCon-perovskite tandem battery provided in the embodiment of the present application.

[0011] Description of reference numerals: 1-electrojet printing device; 101-nozzle; 102-substrate; 103-stage; 104-voltage control device; 2-TOPCon-perovskite stacked battery; 201-N-type silicon wafer; 202-p + Emitter; 203-Al2O3 layer; 204-SiN x layer; 205-Ag electrode; 206-tunneling oxide layer; 207-n + Polysilicon layer; 208 - series connection layer; 209 - hole transport layer; 210 - perovskite layer; 211 - electron transport layer; 212 - transparent electrode; 213 - gate line. DETAILED DESCRIPTION

[0012] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, for clarity, the sizes of layers, regions, elements and their relative sizes may be exaggerated. 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 application, and cannot be understood as limitations on the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0013] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. When the second element, component, region, layer or part is discussed, it does not indicate that the present application necessarily has the first element, component, region, layer or part.

[0014] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 or an electrical connection; 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, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0015] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0016] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to an integer in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed in the present application should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows for broadly including quantitative intervals such as percentage intervals, ratio intervals, and ratio intervals.

[0017] Related art discloses a solar cell electrode printing process based on capillary printing technology. The principle of this process is to fill the capillary made of glass fiber with conductive paste, and by applying air pressure in the capillary, the conductive paste is squeezed out of the capillary and applied to the battery cell. However, this process has the following disadvantages: the thickness of the grid line is limited by the diameter of the capillary, and thinner grid lines require thinner capillaries. As the capillary diameter gradually decreases, the manufacturing cost will increase significantly, and the probability of the capillary being blocked by the paste will also increase significantly; the capillary is easily affected by environmental vibration during the printing process and is difficult to control, resulting in reduced printing accuracy; the contact printing process damages the printing substrate and the capillary. In particular, the loss of the capillary will cause a lot of wear and breakage after long-term use.

[0018] The embodiment of the present application provides an electrospray printing method for solar cell grid lines. Based on this, the limitation of capillaries is eliminated and high-precision and high-resolution grid lines can be obtained. See below for details.

[0019] Hereinafter, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. It should be noted that these exemplary embodiments can be implemented in many different forms and should not be construed as being limited to the embodiments described herein.

[0020] The present application provides a method for electrospraying solar cell grid lines. The method for electrospraying solar cell grid lines may include the following operations: S1. Provide a nozzle 101 and a stage 103 that are arranged opposite to each other, wherein the outlet of the nozzle 101 is a nozzle; thus, provide an electrospray printing device to perform electrospray printing of slurry.

[0021] In some embodiments, the schematic diagram of the structure of the electrospray printing device 1 is shown in Figure 1The electrospray printing device 1 includes a nozzle 101 and a stage 103 which are arranged opposite to each other. The nozzle 101 is in the shape of a hollow tube, which can be a capillary. The stage 103 is used to place the battery cell to be printed (i.e., the substrate 102). The stage 103 and the substrate 102 can be fixed by vacuum adsorption, snap fastening, etc., to ensure that there is no relative displacement between the battery cell and the stage 103 during the printing process.

[0022] In some embodiments, the electrospray printing device further includes a voltage control device 104 , which is used to apply a voltage between the nozzle 101 and the stage 103 and adjust the voltage, thereby adjusting the electric field strength between the nozzle and the substrate 102 .

[0023] S2. The battery cell to be electro-sprayed is used as the substrate 102 and fixed on the stage 103. Thus, the substrate 102 is fixed on the stage 103, which is convenient for electro-spraying.

[0024] In some embodiments, the cell to be electro-printed includes a crystalline silicon solar cell to be printed with a grid line, a thin film solar cell to be printed with a grid line, or a stacked solar cell to be printed with a grid line.

[0025] Specifically, a TOPCon-perovskite tandem cell can be used as the substrate 102. For example, the TOPCon-perovskite tandem cell can be Figure 2 shown.

[0026] Furthermore, the side of the cell to be electro-printed facing the nozzle 101 includes a transparent conductive oxide film (TCO), a single crystal silicon layer, a polycrystalline silicon layer or an amorphous silicon layer, and the above contact surface can be a textured surface or a polished surface.

[0027] Preferably, the contact surface may be a surface treated by ultraviolet light, ozone or / and plasma to increase the contact angle with the slurry.

[0028] S3, the slurry is passed into the nozzle 101, and a voltage is applied between the nozzle 101 and the stage 103, so that the slurry in the nozzle 101 forms a Taylor cone at the nozzle, and the Taylor cone is attached to the substrate 102 under the action of the electric field between the nozzle 101 and the stage 103; at the same time, according to the shape of the grid line pattern, the relative movement between the nozzle 101 and the substrate 102 is controlled to perform electrospray printing on the substrate 102 according to the shape of the grid line pattern. Thus, the slurry is printed on the substrate 102 in the form of electrospray printing to form a preset grid line pattern. Since the driving force is an electric field, and the charged fluid will form a Taylor cone at the nozzle under the drive of the electric field, therefore, this technology can print a pattern that is one order of magnitude smaller than the nozzle size, and has a higher printing resolution. Similarly, since the printing driving force is an electrical signal, the electrical signal is easier to control than air pressure, and this technology can also print a more complex pattern than capillary printing, and has a higher material utilization rate.

[0029] In some embodiments, the paste includes commonly used printing pastes such as silver paste and copper paste.

[0030] In some embodiments, the voltage applied between the nozzle 101 and the stage 103 is 0.1 kV to 3 kV, for example, 0.1 kV, 1 kV, 3 kV, etc.; the distance between the nozzle of the nozzle 101 and the stage 103 is 1 mm to 5 mm, for example, 1 mm, 2 mm, 3 mm, 4.5 mm, 5 mm, etc. Thus, the electric field strength between the nozzle of the nozzle 101 and the stage 103 is 0.02 kV / mm to 3 kV / mm (20 V / mm to 3000 V / mm), which can not only form a Taylor cone at the nozzle, but also avoid the phenomenon of arc discharge caused by air breakdown due to excessive voltage.

[0031] In some embodiments, the inner diameter of the nozzle is 0.1 mm to 0.5 mm, for example, 0.1 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc.

[0032] In some embodiments, the flow rate of the slurry into the nozzle 101 is 0.1 mL / min to 1 mL / min, for example, 0.1 mL / min, 0.5 mL / min, 1 mL / min, etc.

[0033] The inventors found that, through the above-mentioned limitation of electric field intensity and slurry flow rate, the slurry can form a Taylor cone at the nozzle, but the accuracy and consistency of the printed grid lines still do not meet the requirements. The reason is that the fluid forming the Taylor cone is unstable during the printing process, and there is a phenomenon of dripping, which causes the inconsistency and poor accuracy of the grid lines.

[0034] Based on this, in some embodiments of the present application, the surface tension of the slurry is 20 mN / m to 100 mN / m, for example, it can be 20 mN / m, 50 mN / m, 60 mN / m, 89 mN / m, 100 mN / m, etc. Thus, to avoid too low surface tension, the slurry is very easy to drip naturally under the action of gravity at the nozzle, resulting in too large droplets and reduced printing accuracy; at the same time, to avoid too high surface tension, resulting in too large electric field strength required to be applied, resulting in arc discharge caused by air breakdown. The present application embodiment uses the pull-off method to test the surface tension of the slurry, and the test conditions are room temperature (20℃~25℃).

[0035] In some embodiments of the present application, the viscosity of the slurry is 5000cp~10000cp, for example, it can be 5000cp, 6000cp, 7000cp, 9000cp, 10000cp, etc. Thus, it is possible to avoid too low viscosity causing unstable fluid injection during printing, which affects the printing quality; at the same time, it is possible to avoid too high viscosity, which causes the voltage between the nozzle and the printing substrate to be too high during electrospray printing, causing air breakdown to form arc discharge; at the same time, when the viscosity is too high, it is also easy to clog the nozzle. The embodiment of the present application adopts the rotary viscometer method to measure the slurry viscosity, and the test conditions are room temperature (20℃~25℃).

[0036] The embodiment of the present application limits the surface tension and viscosity of the slurry so that the slurry forming the Taylor cone can form a stable jet flow, thereby forming a grid line with a preset accuracy, and the formed grid line has good consistency. For example, a grid line with a width of 1 μm to 30 μm can be formed. However, a grid line of this size is difficult to achieve by relying on the existing screen printing process.

[0037] It is worth noting that the aspect ratio of the grid lines can be adjusted by the number of printing times. For example, repeated printing can be used to increase the aspect ratio.

[0038] Furthermore, on the premise that the appearance accuracy and consistency of the grid line are good, the inventor cut open the solar cell and obtained a cross-sectional view of the grid line and the solar cell. The cross-section of the grid line and the solar cell showed that there was a gap between the grid line and the solar cell, indicating that the grid line did not form a tight bond with the cell.

[0039] Based on this, the inventors adjust the contact angle of the contact surface of the slurry on the substrate by changing the surface energy or roughness of the contact surface on the substrate. In some embodiments, the contact angle between the contact surfaces of the slurry on the substrate is 20° to 50°, for example, the contact angle can be 20°, 30°, 45°, 50°, etc. Thus, it is avoided that the contact angle is less than 20°, the droplet spreads too fast, and the "coffee ring" effect is formed on the substrate, resulting in the phenomenon that the line width of the printed pattern becomes wider and the center area of ​​the line is blank. At the same time, it also avoids the problem of poor wettability caused by excessive contact angle.

[0040] S4. After the electrospray printing operation is completed, the slurry on the substrate 102 is treated to remove the solvent and form gate lines.

[0041] In some embodiments, the treatment includes at least one of heating, blowing, and vacuuming. Thus, after the slurry is printed on the substrate, it is dried by heating, blowing, etc. to remove the solvent and volatile components in the slurry to form the final grid lines. Exemplarily, it can be kept at 100°C to 150°C for 15min to 20min.

[0042] The second aspect of the embodiment of the present application provides a solar cell, which is prepared by the first aspect of the embodiment of the present application. Thus, the width of the grid line is 1μm to 30μm. While reducing the amount of electrode metal used, the grid line can efficiently collect photoelectrons generated on the surface of the solar panel and transmit them to other parts of the cell, such as the reflective layer and the transparent conductive film, and finally to the external load system. At the same time, due to the further reduction in the size of the grid line, the cell can better absorb light, which is beneficial to improving the photoelectric conversion efficiency of the solar cell.

[0043] The following will conduct performance tests on the TOPCon-perovskite tandem battery manufacturing method provided in the embodiments of the present application and related comparative examples.

[0044] [Preparation Example] The TOPCon-perovskite tandem cell was prepared using the following preparation method: (1) Providing a bottom battery, the bottom battery comprising an N-type silicon wafer 201, one end of the N-type silicon wafer 201 being a polished surface and the other end being a textured surface, and one side of the textured surface being provided with p + Emitter 202, Al2O3 layer 203 and SiN x The outermost layer 204 is provided with an Ag electrode 205; the side of the polished surface is provided with a tunnel oxide layer 206 and an n + Polysilicon layer 207; (2) In n + A 5 nm thick indium tin oxide transparent conductive film (ITO) is deposited on the polysilicon layer 207 by using an ALD method as a series connection layer 208; (3) Depositing 10 nm thick (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz) on the tandem layer 208 as the hole transport layer 209; preparing 500 nm FAPbI3 on ​​the hole transport layer 209 as the perovskite layer 210; depositing 10 nm C 60 As the electron transport layer 211 , 50 nm of IZO was then formed on the electron transport layer 211 as the transparent electrode 212 .

[0045] [Example 1] Step 1: Provide an electro-jet printing device 1, which includes a nozzle 101 and a stage 103 that are arranged opposite to each other. The nozzle 101 has a nozzle at its outlet, the distance between the nozzle and the stage 103 is 4.5 mm, and the inner diameter of the nozzle is 0.25 mm.

[0046] Step 2: After the IZO surface of the TOPCon-perovskite tandem battery of the preparation example is treated with plasma, it is adsorbed on the stage 103 as a substrate 102, and one side of the IZO is arranged opposite to the nozzle 101; Step 3: The slurry is introduced into the nozzle 101 at a flow rate of 0.5 mL / min, and a voltage is applied between the nozzle 101 and the stage 103 so that the electric field strength is 1500 V / mm, so that the slurry in the nozzle 101 forms a stable Taylor cone at the nozzle, and the Taylor cone is attached to the substrate 102 under the action of the electric field between the nozzle 101 and the stage 103; at the same time, according to the shape of the grid line pattern, the relative movement between the nozzle 101 and the substrate 102 is controlled to perform electrospray printing according to the shape of the grid line pattern; Among them, the slurry used is HC449 slurry purchased from Suzhou Jingyin New Material Technology Co., Ltd.; under room temperature conditions, after relevant tests, the viscosity of the slurry is 9000cp and the surface tension is 89 mN / m; before IZO plasma treatment, the contact angle between the slurry and IZO is 10°, and after plasma treatment, the contact angle between the slurry and IZO increases to 35°.

[0047] Step 4: vacuum drying at 100° C. for 15 min to complete the preparation of the gate line 213 and obtain the TOPCon-perovskite stacked cell 2.

[0048] [Example 2] The other operations are the same as those in Example 1, except that: In step 1, the inner diameter of the nozzle is 0.1 mm; In step 3, the flow rate of the slurry was 0.1 mL / min and the electric field strength was 100 V / mm; The slurry used was prepared by adjusting the contents of components in the HC449 slurry so that the surface tension of the slurry was 20 mN / m, the viscosity was 7000 cp, and the contact angle with the ozone-treated IZO was 20°.

[0049] [Example 3] The other operations are the same as those in Example 1, except that: In step 1, the inner diameter of the nozzle is 0.5 mm; In step 3, the flow rate of the slurry is 1 mL / min and the electric field strength is 2900 V / mm; The slurry used was prepared by adjusting the contents of components on the basis of HC449 slurry, so that its surface tension was 100 mN / m, its viscosity was 10000 cp, and the contact angle between the slurry and the IZO on the UV-treated substrate was 50°.

[0050] [Example 4] The other operations are the same as those in Example 1, except that: The slurry used in step 3 is HC449 slurry with the content of components adjusted so that the surface tension is 10 mN / m.

[0051] [Example 5] The other operations are the same as those in Example 1, except that: The slurry used in step 3 is HC449 slurry with the content of components adjusted so that the surface tension of the slurry is 120 mN / m. In order to form a stable Taylor cone at the nozzle of the nozzle 101, a voltage is applied so that the electric field strength is 3200 V / mm.

[0052] [Example 6] The other operations are the same as those in Example 1, except that: The slurry used in step 3 is prepared by adjusting the contents of components in the HC449 slurry so that the viscosity of the slurry is 500 cp.

[0053] [Example 7] The other operations are the same as those in Example 1, except that: The slurry used in step 3 is HC449 slurry with the components adjusted so that the viscosity of the slurry is 5000 cp. In order to form a stable Taylor cone at the nozzle of the nozzle 101, a voltage is applied so that the electric field strength is 3200 V / mm.

[0054] [Example 8] The other operations are the same as those in Example 1, except that: The IZO surface of the TOPCon-perovskite tandem cell prepared in step 2 was not plasma treated, and the contact angle between the slurry and the IZO of the substrate that was not plasma treated was 10°.

[0055] [Comparative Example 1] The slurry of Example 1 was used for screen printing.

[0056]

Test example

[0057] Table 1:

[0058] Table 2

[0059] It can be seen from Table 2 above that the size of the grid line prepared by the electrospray printing method can be controlled below 30μm, and the lowest can reach 4μm. Compared with the size of Comparative Example 1, the size of the grid line can be greatly reduced. Combined with Table 1, it can be seen that when the viscosity of the slurry is 5000cp~10000cp, the surface tension is 20 mN / m~100 mN / m and the contact angle is 20°~50°, the size of the prepared grid line is consistent and good, and there is no appearance defect. The surface tension of the slurry used in Example 4 is too small, resulting in poor consistency in the size of the grid line printed by electrospraying, and there are enlarged areas on the grid line. The surface tension of the slurry used in Example 5 is too large, resulting in the field strength required to form the Taylor cone as high as 3200V / mm, arc discharge occurs, and there are unsafe factors. In Example 6, the viscosity is too low, resulting in discontinuous defects in the grid line. In Example 7, the viscosity is too low, resulting in the field strength required to form the Taylor cone as high as 3200V / mm, arc discharge will also occur, and there are unsafe factors. The contact angle between the slurry used in Example 8 and the contact surface is too low. This is because the slurry spreads on the contact surface too quickly, forming a "coffee ring" effect on the substrate, causing the printed pattern line width to become wider and the center area of ​​the line to be blank, resulting in a wide grid line size and a loose bonding with the substrate.

[0060] It should be noted that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 application. The orientation words "inside" and "outside" refer to the inside and outside relative to the outline of each component itself. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Therefore, the exemplary term "above..." can include both "above..." and "below..." orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here are interpreted accordingly.

[0061] It should also be noted that "one embodiment", "another embodiment", "embodiment", etc. mentioned in this application refer to the specific features, structures or characteristics described in conjunction with the embodiment included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in conjunction with any embodiment, it is claimed that the realization of such feature, structure or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0062] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0063] It should also be noted that the above are only preferred embodiments of the present application, and the patent protection scope of the present application is not limited thereto. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for electrospraying grid lines of solar cells, characterized in that: The following operations are included: Providing a nozzle and a stage that are arranged opposite to each other, wherein the nozzle is provided at an outlet of the nozzle; The battery sheet to be electrosprayed is used as a substrate and fixed on the stage; Performing an electrospray printing operation: passing the slurry into the nozzle, applying a voltage between the nozzle and the stage, so that the slurry in the nozzle forms a Taylor cone at the nozzle, and the Taylor cone adheres to the substrate under the action of the voltage; at the same time, according to the shape of the grid line pattern, controlling the relative movement between the nozzle and the substrate, so as to perform electrospray printing on the substrate according to the shape of the grid line pattern; After the electrospray printing operation is completed, the slurry on the substrate is treated to remove the solvent and form grid lines.

2. The electrospray printing method for solar cell grid lines according to claim 1, characterized in that: The following operations are also included: The treatment includes at least one of heating, blowing, and vacuuming.

3. The electrospray printing method for solar cell grid lines according to claim 1, characterized in that: The applied voltage is 0.1 kV to 3 kV; The distance between the nozzle of the spray head and the stage is 1 mm to 5 mm.

4. The electrospray printing method for solar cell grid lines according to claim 1, characterized in that: The inner diameter of the nozzle is 0.1 mm to 0.5 mm; and / or The flow rate of the slurry entering the nozzle is 0.1 mL / min to 1 mL / min.

5. The method for electrospraying solar cell grid lines according to claim 1, characterized in that: The surface tension of the slurry is 20 mN / m to 100 mN / m.

6. The electrospray printing method for solar cell grid lines according to claim 1, characterized in that: The viscosity of the slurry is 5000cp-10000cp.

7. The electrospray printing method for solar cell grid lines according to claim 1, characterized in that: The contact angle between the contact surface of the slurry and the substrate is 20° to 50°.

8. The method for electrospraying solar cell grid lines according to any one of claims 1 to 7, characterized in that: The battery sheet to be electro-printed comprises: At least one of a crystalline silicon solar cell, a thin film solar cell, and a stacked solar cell.

9. The method for electrospraying solar cell grid lines according to claim 8, characterized in that: The contact surface between the substrate and the slurry includes a transparent conductive oxide film, a single crystal silicon layer, a polycrystalline silicon layer or an amorphous silicon layer.

10. The method for electrospraying solar cell grid lines according to claim 9, characterized in that: The contact surface is a surface treated with ultraviolet light, ozone or / and plasma.

11. A solar cell, characterized in that: The invention comprises grid lines prepared by the electrospray printing method according to any one of claims 1 to 10.

12. The solar cell according to claim 11, characterized in that: The width of the gate line is 1 μm to 30 μm.

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