Printing system of photovoltaic solar cell electrode

Abstract

The invention relates to the field of branch cells, in particular to a photovoltaic solar cell electrode printing system which comprises a platform, a liquid supply system, a microfluid nozzle, a high-voltage power supply system and a substrate, the microfluid nozzle is connected with the high-voltage power supply system and the liquid supply system used for conveying conductive silver paste, the high-voltage power supply system is connected with the platform, and the substrate is connected with the platform. The substrate is placed on the uppermost portion of the platform and provided with grid lines, the microfluid nozzle is made of conductive materials, and a moving device is installed in the platform. The battery electrode prepared by the invention has higher conductivity and better photoelectric property, reduces material consumption and waste generation, and has good economic benefit and environmental protection value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery, in particular to a printing system of photovoltaic solar cell electrode. BACKGROUND

[0002] As an important part of renewable energy, the performance and cost of photovoltaic solar cell directly affect the popularization and application of solar power generation.

[0003] The electrode is one of the key components of solar cell, and its conductivity and contact quality with photovoltaic material are crucial to the efficiency of the cell. Currently, the electrode is mostly made by traditional silver paste coating method, but this method has the problems of low precision, large material waste, obvious edge effect, etc., which limits the improvement of the performance of the cell. SUMMARY

[0004] To achieve the above-mentioned purpose, the purpose of the present application is to provide a printing system of photovoltaic solar cell electrode, which can solve the problems in the background art. The core of the present application is to use the electrohydrodynamic effect under the action of electric field force to make the silver paste form Taylor cone at the nozzle and spray out small droplets. These droplets are deposited on the surface of the photovoltaic material according to the preset trajectory under the action of precisely controlled electric field and airflow, forming an accurately designed electrode pattern. This process realizes the on-demand spraying of silver paste, reducing material waste. The present application provides the following technical scheme:

[0005] A printing system of photovoltaic solar cell electrode, comprising a platform, a liquid supply system, a microfluidic nozzle, a high-voltage power supply system and a substrate, the microfluidic nozzle is connected with the high-voltage power supply system and the liquid supply system for transporting conductive silver paste, the high-voltage power supply system is connected with the platform, the substrate is placed on the uppermost part of the platform and the substrate is provided with a grid line, the microfluidic nozzle is made of conductive material, a moving device is installed in the platform, the moving device can realize X-Y-Z three-axis nanometer positioning, the liquid supply system is used to transport conductive silver paste to the microfluidic nozzle at a constant flow rate, the high-voltage power supply system is used to apply a direct current high-voltage electric field between the microfluidic nozzle and the substrate, the conductive silver paste is driven by the electric field force to form a sub-micron to dozens of microns jet, and is deposited on the substrate as a continuous or discrete conductive grid line structure, the viscosity of the conductive silver paste is 1-100 mPa·s and has conductivity, the moving device can realize X-Y-Z three-axis nanometer positioning, the composition structure is as follows: (1) mechanical structure: precision guide rail, air bearing and flexible hinge; (2) drive system: nanometer actuator and displacement amplification mechanism; (3) sensor and feedback system: position detection and closed-loop control device; (4) control system; (5) damping and vibration isolation device.

[0006] As a further scheme of the present application: the electric field strength formed by the high-voltage power supply system is in the range of 1-5 kV / mm.

[0007] As a further scheme of the present application: the inner diameter of the microfluidic nozzle is 1-100 μm.

[0008] As a further scheme of the present application: the high-voltage power supply system includes a pulse voltage control module for generating a frequency-adjustable pulse voltage signal to realize drop-on-demand jet control, and the pulse voltage control module includes the following core parts: (1) a pulse generator: generating a basic pulse signal to determine the frequency, width (duty cycle), and initial amplitude of the pulse; (2) a voltage regulation circuit: adjusting the amplitude (voltage level) of the pulse, involving voltage boosting, voltage reduction, and voltage stabilization; (3) a drive circuit: amplifying the power of the pulse signal to ensure that it can drive subsequent loads (such as motors, power MOSFETs, IGBTs, etc.); (4) a protection circuit: preventing damage to the module or load due to abnormal conditions such as overvoltage, overcurrent, and short circuit; (5) isolation and coupling: achieving electrical isolation between input and output (safety or anti-interference requirements); (6) a filtering and shaping module: optimizing the pulse waveform to reduce noise or ringing effects; (7) a control and feedback module; (7) an interface and communication module: interacting with external systems (such as configuring parameters or monitoring status).

[0009] As a further scheme of the present application: the microfluidic nozzle is a conical structure made of one of stainless steel, gold-plated glass capillary, or conductive polymer, and the microfluidic nozzle is a multi-nozzle array structure capable of printing multiple grid lines in parallel.

[0010] As a further scheme of the present application: the substrate is a flexible transparent conductive substrate made of one of polyethylene terephthalate (PET), polyimide (PI), or indium tin oxide (ITO) glass.

[0011] As a further scheme of the present application: the liquid supply system includes a micro-syringe pump or a gas pressure controller, capable of delivering conductive silver paste at a flow rate of 1-500 nL / min, and the liquid supply system is a core module that ensures that the ink is delivered to the print head in a stable and controllable manner, and its design directly affects the printing quality (such as droplet consistency, ejection frequency). According to the properties of the ink (viscosity, volatility) and the printing requirements (high precision, high speed), the liquid supply system usually uses a micro-syringe pump or a gas pressure controller as the driving source. The micro-syringe pump liquid supply system drives the piston / screw through a precision stepper motor or servo motor to push the ink in the syringe to output with precise flow rate, realizing continuous or pulsed liquid supply. The gas pressure controller liquid supply system drives the ink from the liquid tank to the print head by adjusting the gas pressure (positive or negative), and the pressure range is usually 0-100 kPa (accurate to ±0.1 kP).

[0012] As a further scheme of the present application: the conductive silver paste comprises the following raw materials in weight fraction: 1-50% of metal nano-silver particles, 10-80% of metal micron-silver particles, 1-8% of glass powder, 0.5-5% of organic auxiliary agent, and the rest of organic carrier, the organic carrier comprises resin and solvent, the resin comprises one or more of ethyl cellulose, polyvinyl butyral, acrylic resin and phenoxy resin, the weight fraction of the resin in the conductive silver paste is 0.5-5%, the solvent comprises at least one of diethylene glycol butyl ether, terpineol, diethylene glycol butyl ether acetate, benzyl benzoate, diethylene glycol dibutyl ether, dimethyl adipate, dimethyl phthalate, alcohol ester twelve and alcohol ester sixteen, the weight fraction of the solvent in the conductive silver paste is 5-50%; the organic auxiliary agent comprises at least one of silicone oil, dispersant and thixotropic agent.

[0013] As a further scheme of the present application: a printing system of photovoltaic solar cell electrode further comprises an environment control unit and a real-time monitoring system, the environment control unit is used for adjusting the temperature and humidity of the printing environment; the real-time monitoring system comprises a high-speed camera and an optical sensor, and is used for observing the jet shape in real time and feeding back the adjustment of the electric field intensity or the substrate displacement parameter.

[0014] Compared with the prior art, the present application has the following beneficial effects:

[0015] The battery electrode prepared by the present application has higher conductivity and better photoelectric performance, while reducing material consumption and waste generation, and has good economic benefit and environmental value. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the printing system of the photovoltaic solar cell electrode in the embodiment of the present application.

[0017] In the figure: 1-platform; 2-substrate; 3-high-voltage power supply system; 4-microfluidic nozzle; 5-liquid supply system; 6-grid line; 7-conductive silver paste. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0019] The present application aims at the deficiencies of the existing photovoltaic solar cell electrode preparation technology, proposes to use the electrohydrodynamic printing technology, realizes the high-precision and low-cost manufacturing of electrode patterns by accurately controlling the formation and deposition of silver paste droplets, and aims to improve the photoelectric conversion efficiency and economic benefits of the cell. In view of different needs of photovoltaic solar cells, the present application designs various optimized electrode pattern structures, including but not limited to grid-shaped, fork-shaped and micro-nano composite structures, aiming to maximize the light absorption efficiency while reducing the resistance loss and improving the current collection efficiency. In order to realize efficient and stable electrohydrodynamic printing, the present application designs an integrated printing system, including a microfluidic nozzle, a high-voltage power supply system, a precision moving platform and the like. The equipment adopts a closed-loop control strategy to ensure that the droplet size, speed and position are accurately controllable during the printing process, thereby improving the printing quality. In view of the special requirements of electrohydrodynamic printing, the present application develops a conductive silver paste with low viscosity, high conductivity and good rheological property, and by adding specific dispersants, stabilizers and conductive enhancers, the printing performance of the conductive silver paste and the conductivity of the electrode are improved.

[0020] The specific implementation of the present application is described in detail below in combination with specific embodiments.

[0021] Embodiment 1: High-precision grid line printing on rigid substrate

[0022] 1. System configuration

[0023] - High-voltage power supply system 3: DC high-voltage power supply (0-30 kV) with pulse control module (frequency 1-1000 Hz adjustable). - Microfluidic nozzle 4: stainless steel conical nozzle, inner diameter 20 μm.

[0024] - Platform 1: ITO glass substrate 2 (thickness 1.1 mm), positioning accuracy of platform 1 displacement ±100 nm.

[0025] - Liquid supply system 5: microsyringe pump, flow rate 50 nL / min.

[0026] - Environmental control: temperature 25±1℃, humidity 40±5%.

[0027] - Monitoring system: high-speed camera (10,000 fps) for real-time observation of jet shape.

[0028] 2. Formula of conductive silver paste 7

[0029] - Metal nano-silver particles: particle size 50 nm, proportion 30 wt%.

[0030] - Metal micro-silver particles: particle size 2 μm, proportion 30 wt%.

[0031] - Glass powder: PbO-Bi2O3-TeO2-SiO2 system glass powder, softening temperature 280℃, proportion 3 wt%.

[0032] - Organic vehicle: ethyl cellulose (3 wt%) + diethylene glycol butyl ether acetate 20 wt% + diethylene glycol dibutyl ether 3 wt% + alcohol ester sixteen 10 wt%).

[0033] - Organic vehicle: ethyl cellulose (3 wt%) + diethylene glycol butyl ether acetate 20 wt% + diethylene glycol dibutyl ether 3 wt% + alcohol ester sixteen 10 wt%).

[0034] 3. Printing process

[0035] - Applied electric field strength 3 kV / mm (distance between microfluidic nozzle 4 and substrate 2 is 1 mm).

[0036] - Pulse mode: frequency 200 Hz, duty cycle 50% (drop mode).

[0037] - Substrate 2 moving speed 10 mm / s, printed line width 8 pm.

[0038] 4. Performance test

[0039] - Line width uniformity: 8 ± 0.5 pm (SEM measurement).

[0040] - Sheet resistance: 4.2 W / sq after sintering (250 °C / 30 min).

[0041] - Adhesion: tested by crosshatch method, adhesion rating 5B (ASTM D3359).

[0042] Example 2: Parallel gate line printing on flexible substrate

[0043] 1. System configuration

[0044] - Microfluidic nozzle 4: multi-nozzle array (5 x 1 arrangement, gold-plated glass capillary, inner diameter 30 pm).

[0045] - Stage 1 : PET substrate 2 (thickness 125 pm), surface coated with silane coupling agent (KH-550).

[0046] - Liquid supply system 5: air pressure controller, total flow rate 250 nL / min (50 nL / min per nozzle).

[0047] 2. Formulation of conductive silver paste 7

[0048] - Metal nano-silver particles: particle size 100 nm, proportion 50 wt%.

[0049] - Metal micro-silver particles: particle size 1.0 pm, proportion 10 wt%.

[0050] - Glass powder: PbO-B2O3-SiO2system glass powder, softening temperature 305 °C, proportion 5.0 wt%.

[0051] - Organic vehicle: acrylic resin (2%) + phenoxy resin (0.5 wt%) + diethylene glycol butyl ether acetate (balance). - Organic additives: thixotropic agent Japan Kasei Chemical 6500 1 wt%, dispersant Akzo Nobel TDO 0.5%

[0052] 3. Printing process

[0053] - Continuous jet mode, electric field strength 2.5 kV / mm (distance between microfluidic nozzle 4 and substrate 2 of 2 mm).

[0054] - Substrate 2 moving speed 20 mm / s, 5 parallel printed lines 6 (line width 15 pm).

[0055] 4. Performance tests

[0056] - Bending performance: 1000 times bending with a curvature radius of 5 mm, square resistance change rate less than 3%.

[0057] - Light transmittance: light transmittance of PET substrate 2 and lines 6 no less than 85% (550 nm wavelength).

[0058] Example 3: Stable jet control of high viscosity conductive silver paste

[0059] 1. System improvement

[0060] - High voltage power supply system 3: increase feedback control module, dynamically adjust voltage (1-5 kV / mm) according to jet shape.

[0061] - Liquid supply system 5: preheating module (40 °C) to reduce the viscosity of conductive silver paste.

[0062] 2. Formulation of conductive silver paste 7

[0063] - Metal nano-silver particles: particle size 200 nm, proportion 30 wt%.

[0064] - Metal micro-silver particles: particle size 1.2 pm, proportion 20 wt%.

[0065] - Glass powder: PbO-B2O3-SiO2system glass powder, softening temperature 290 °C, proportion 8.0 wt%.

[0066] - Organic vehicle: polyvinyl butyral (3%) + acrylic resin (1.0 wt%) + diethylene glycol butyl ether acetate (36.5 wt%). - Organic additives: thixotropic agent Japan Kasei Chemical 6500 1 wt%, dispersant Akzo Nobel TDO 0.5%.

[0067] 3. Printing process

[0068] - Electric field intensity 4.5 kV / mm (distance between microfluidic nozzle 4 and substrate 2 is 0.8 mm).

[0069] - Substrate 2 moving speed 5 mm / s, printed line width 25 pm.

[0070] 4. Performance test

[0071] - Line edge roughness (LER): less than 5% (measured by laser profilometer).

[0072] - Sintering temperature: high-temperature sintering (720 °C), sheet resistance 8.7 Ω / sq.

[0073] Example 4: Complex pattern printing with real-time feedback adjustment

[0074] 1. System configuration

[0075] - Monitoring system: integrated optical sensor (detects deposition position deviation) and AI algorithm (dynamically adjusts displacement path). - Platform 1: 6-axis mechanical arm (positioning accuracy ±1 pm) for printing on curved substrate 2.

[0076] 2. Printing process

[0077] - Printed pattern: interlaced grid lines 6 and dot matrix electrodes (line width 10 pm, dot diameter 20 pm).

[0078] - Real-time feedback: trigger voltage fine-tuning (±0.2 kV / mm) when jet deviation is greater than 2 pm.

[0079] 3. Performance test

[0080] - Pattern accuracy: position deviation less than 1 pm (3D optical profilometer).

[0081] - Efficiency: 400% improvement in efficiency compared to single-nozzle printing.

[0082] Through extensive experiments, the present application determines the key process parameters that affect printing quality, such as electric field intensity, jetting pressure, printing speed, substrate temperature, etc., and establishes a mathematical model between process parameters and electrode performance, achieving intelligent optimization of process parameters.

[0083] It should be noted that in the present application, unless otherwise explicitly specified and limited, the terms "fixed", "provided", and other terms should be understood broadly, for example, can be welded connection, or bolted connection, or integrated; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship of two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0084] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A printing system for photovoltaic solar cell electrodes comprising a platform, a liquid supply system, a microfluidic nozzle, a high voltage power supply system and a substrate, characterized in that, The micro-fluid nozzle is connected with a high-voltage power supply system and a liquid supply system for delivering conductive silver paste respectively, the high-voltage power supply system is connected with a platform, the substrate is placed on the uppermost part of the platform and the substrate is provided with a grid line, the micro-fluid nozzle is made of conductive material, and a moving device is installed in the platform.

2. The printing system of photovoltaic solar cell electrodes according to claim 1, characterized in that, The high-voltage power supply system comprises a pulse voltage control module.

3. The printing system of photovoltaic solar cell electrodes according to claim 1 or 2, characterized in that, The micro-fluid nozzle is a conical structure, and the material of the micro-fluid nozzle is selected from one of stainless steel, gold-plated glass capillary and conductive polymer.

4. The printing system of photovoltaic solar cell electrodes according to claim 3, characterized in that, The micro-fluid nozzle is a multi-nozzle array structure.

5. The printing system of photovoltaic solar cell electrodes according to claim 1, characterized in that, The liquid supply system comprises a micro-injection pump or a gas pressure controller.

6. The printing system of photovoltaic solar cell electrodes according to claim 1, characterized in that, An environmental control unit and a real-time monitoring system are further included, and the real-time monitoring system comprises a high-speed camera and an optical sensor.

7. The printing system of photovoltaic solar cell electrodes according to claim 1, characterized in that, The conductive silver paste comprises the following raw materials in weight fraction: 1-50% of metal nano-silver particles, 10-80% of metal micro-silver particles, 1-8% of glass powder, 0.5-5% of an organic auxiliary agent, and the remaining organic carrier, the organic carrier comprises resin and solvent, and the organic auxiliary agent comprises at least one of silicon oil, a dispersing agent and a thixotropic agent.

8. The printing system of photovoltaic solar cell electrodes according to claim 7, characterized in that, The resin comprises one or more of ethyl cellulose, polyvinyl butyral, acrylic resin and phenoxy resin, the weight fraction of the resin in the conductive silver paste is 0.5-5%, the solvent comprises at least one of diethylene glycol butyl ether, terpineol, diethylene glycol butyl ether acetate, benzyl benzoate, diethylene glycol dibutyl ether, dimethyl adipate, dimethyl phthalate, alcohol ester twelve and alcohol ester sixteen, and the weight fraction of the solvent in the conductive silver paste is 5-50%.

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