Device and method for carbon fiber electrode active material coating and CVD (Chemical Vapor Deposition) growth

Abstract

The invention discloses a device and a method for carbon fiber electrode active material coating and CVD (chemical vapor deposition) growth, and belongs to the field of carbon fiber electrodes. The device comprises an array coating machine and a CVD gas distribution system. The array coating machine is mainly used for preparing the positive electrode of the lithium battery, and the CVD growth process is mainly used for preparing the negative electrode of the lithium battery. The array coating machine is two-coordinate numerical control equipment, and a piezoelectric valve is controlled by writing a control program to quantitatively coat a target material. And the surface of the carbon fiber can be coated in an array shape at the minimum interval of 3mm, so that after the carbon fiber has electrode activity, a composite material prepared from the carbon fiber still has relatively good interlayer mechanical property. The gas distribution system is of a cuboid cabinet structure, trundles are installed below the gas distribution system to facilitate movement, and a main control panel is arranged right in front of the device. The left side surface is a gas inlet, the right side surface is a gas outlet, the back surface of the device is a device power supply interface, and the upper surface of the device is a device working state indicator and is used for carrying out A-path or B-path atmosphere supply control on different CVD growth equipment.

Description

Technical Field

[0001] The invention belongs to the field of carbon fiber electrodes, and in particular relates to a device and method for coating active substances and CVD growth of carbon fiber electrodes. Background Art

[0002] Using carbon fiber as lithium battery electrode is an important way to achieve structural energy storage, among which the preparation process of negative electrode material is more difficult. In order to make carbon fiber material produce electrode activity, growing carbon nanotubes on carbon fiber by chemical vapor deposition can form a more ideal negative electrode material.

[0003] In order to realize such negative electrode materials, the corresponding process must maintain the original mechanical properties of carbon fiber and realize the electrochemical function of battery electrode, which puts forward high requirements on the process. Its typical process requires that the honeycomb array of active materials be coated on the surface of carbon cloth, and then heated at 500 ℃ in a tubular furnace under Ar / NH3 flow for 30 minutes. After cooling, melamine is added to the porcelain boat, and the carbon fiber cloth is placed on top of the porcelain boat, and then heated to 850 ℃ in an argon atmosphere (flow rate: 50 mL / min) and kept warm for 2 hours.

[0004] The general coating device adopts flat overall coating or interval coating, and the coating control accuracy is low. Large-area active material coating is not conducive to the structural process of multi-layer carbon fiber materials. The active material weakens the interlayer strength of carbon fiber composite materials to a certain extent. Through the active material coating similar to the honeycomb array, some non-coated areas are reserved on the carbon fiber surface, so that these areas provide uniform interlayer strength on the entire plane of the material, which is conducive to improving the mechanical properties of the structure.

[0005] The laboratory gas distribution device (system) can be divided into the front-end gas source part, the intermediate piping part, the back-end secondary distribution and terminal gas use part, and the monitoring and alarm part according to the process steps. It includes not only the main equipment such as special gas cabinets and gas cylinder racks, but also auxiliary equipment such as waste gas treatment cabinets, air compressors, vacuum pumps, and nitrogen generators. In the gas distribution system, multiple devices need to cooperate with each other. When supplying gas to equipment that requires a gas environment, it is often necessary to add a gas supply control system to control the pressure, flow rate, and time of the gas supply. Usually, this gas supply control system is only applicable to the gas control requirements of a certain process. When the required gas composition changes or other control parameters change, a new set of gas supply control devices is required to complete the corresponding gas supply control.

[0006] The device for electrode active material dot matrix coating machine and CVD growth provided by the present invention has strong versatility, can meet the needs of continuous production of carbon fiber negative electrode materials, and can realize the opening and closing of gas pipelines, gas flow control, gas delivery timing control, harmful gas recovery and treatment and other functions, and when the gas composition changes, only the flow meter needs to be replaced in the control system to adapt to the new control requirements. Summary of the invention

[0007] The object of the present invention is to provide a device and method for coating and CVD growth of carbon fiber electrode active materials.

[0008] Based on the above purpose, the present invention adopts the following technical solutions: A device for coating and CVD growth of carbon fiber electrode active material, comprising an array coating machine for preparing electrode positive electrodes and a CVD equipment gas distribution system for preparing electrode negative electrodes, the array coating machine comprising a heating platform, a winding mechanism and a dispensing mechanism, an x-guide rail and a y-guide rail are arranged on the heating platform in parallel at the front and rear ends of the heating platform, the two ends of the y-guide rail are respectively slidably arranged on the x-guide rail, an up-and-down moving mechanism is arranged on the y-guide rail, the up-and-down moving mechanism comprises an up-and-down moving slide rail, a cylinder is arranged on the side of the up-and-down moving slide rail facing the y-guide rail, a mounting plate is arranged on the side of the up-and-down moving slide rail facing the heating platform, a dispensing mechanism is arranged on the mounting plate, the CVD equipment gas distribution system comprises a gas A pipeline and a gas B pipeline, the gas A pipeline and the gas B pipeline are respectively provided with gas pipe quick connectors at the gas inlet ends, the gas outlet ends are connected in parallel to the total gas inlet pipeline through a confluence valve, and the gas A pipeline and the gas B pipeline are sequentially provided with a manual ball valve, a solenoid valve, a flow meter and a one-way valve from the gas inlet end to the gas outlet end.

[0009] Furthermore, the winding mechanism comprises a winding wheel and an unwinding wheel arranged at both ends of the heating platform, and guide rods are arranged between the winding wheel and the heating platform and between the unwinding wheel and the heating platform.

[0010] Furthermore, the maximum heating temperature of the heating platform is 150°C, and the temperature control accuracy is ±1°C.

[0011] The dispensing mechanism is a single-liquid screw valve.

[0012] The method for coating carbon fiber with active material and growing it by CVD using the above-mentioned device is as follows: (1) The substrate is mounted on the winding mechanism of the dot matrix coating machine, and the electrode active material slurry is poured into the barrel; (2) Determine the distance between the barrel and the heating platform according to the concentration of the slurry and the coating amount; (3) Programming is performed according to the pattern shape of the coating, and the heating temperature of the heating platform is set to perform coating and dispensing of the electrode active material. At the same time, the winding mechanism is wound until the coating is completed; (4) Place the raw materials containing the elements constituting the thin film into the porcelain boat of the quartz tube of the tubular furnace, place the substrate into the other end of the quartz tube, connect the quick connectors of the gas A pipeline and the gas B pipeline to the gas cylinder A and the gas cylinder B respectively, keep the manual ball valves on the gas A pipeline and the gas B pipeline closed, and connect the main air inlet pipeline to the gas supply end of the quartz tube through the connecting plug; (5) Press the start button of gas circuit A and / or gas circuit B, then the solenoid valve on gas pipeline A and / or gas pipeline B opens, the timed disconnection relay of gas circuit A and / or gas pipeline B starts, and the relay disconnection time is set. After the setting is completed, press the closing button of gas circuit A and / or gas circuit B, and the solenoid valve on gas pipeline A and / or gas pipeline B closes; (6) Operate the manual ball valve on the gas A pipeline and / or the gas B pipeline to open the manual ball valve slightly, so that there is less gas flow capacity in the gas line A and / or the gas line B. Press the start button of the gas line A and / or the gas line B to open the solenoid valve on the gas A pipeline and / or the gas B pipeline. At this time, the gas pressure flows to the inlet of the flow meter on the gas A pipeline and / or the gas B pipeline; (7) Turn on the adjustment knob of the flow meter on the gas A pipeline and / or the gas B pipeline to adjust the flow rate to the gas flow rate required by the process. If the flow rate requirement cannot be met even if the knob is turned to a larger value, increase the opening angle of the manual ball valve until the required flow rate is reached. At this time, gas supply to the CVD equipment has begun until the timing relay starts to cut off the gas supply. Manually close the control buttons of gas line A and gas line B. (8) When the timing of both gas supply is over, close the valves of gas cylinders A and B, turn off the power of the equipment, place the manual ball valves on the two gas pipelines in the cut-off position, and adjust the flow meter regulating valves on the two gas pipelines to the closed state.

[0013] Furthermore, in step (2), when the coating amount is ≤0.1 mL / cm 2 When the piezoelectric valve is at a distance of less than 1 mm from the surface of the heating platform, 2 ﹤Coating volume﹤0.5mL / cm 2 When the coating volume is 0.5mL / cm 2 When the pressure is above 200 °C, the distance between the piezoelectric valve and the surface of the heating platform should be controlled at 2 mm.

[0014] Furthermore, the substrates in step (1) and step (4) are both carbon fiber cloth.

[0015] Furthermore, the raw material containing the elements constituting the thin film refers to a raw material containing carbon.

[0016] Specifically, the gas A pipeline is a mixture of argon and ammonia, and the gas flow rate of the gas A pipeline is 50~100 mL / min; the gas B pipeline is argon, and the argon flow rate of the gas B pipeline is 20~80 mL / min.

[0017] Active material coating is mainly used to prepare lithium battery positive electrodes, and CVD growth process is mainly used to prepare lithium battery negative electrodes.

[0018] The device and method for coating carbon fiber lithium battery negative electrode active material and CVD growth provided by the present invention can coat the carbon fiber surface in an array with a minimum interval of 3mm, so that the carbon fiber has electrode activity, and the composite material still has good interlayer mechanical properties. The dual atmosphere gas supply system established is universal and can be easily moved to control the atmosphere supply of A or B for different CVD growth equipment. The adjustable parameter range is wide, the volume flow control and time control are adjustable, and it can be manually forced on and off. It is suitable for the atmosphere environment application during CVD growth in laboratories or small production units, occupies a small area, and saves equipment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the array coating machine of the present invention; Figure 2 It is a structural schematic diagram of the array coating machine of the present invention; Figure 3 It is a structural schematic diagram of the gas distribution system of the CVD equipment of the present invention; Figure 4 is a schematic diagram of the carbon fiber structure after coating by the array coating machine of the present invention; In the figure: 1. x-guide rail, 2. up and down moving mechanism, 21. up and down moving slide rail, 22. cylinder, 23. mounting plate, 3. y-guide rail, 4. carbon fiber cloth, 51. winding wheel, 52. unwinding wheel, 6. heating platform, 71. first guide rod, 72. second guide rod, A1 / B1. air pipe quick connector; A2 / B2. manual ball valve; A3 / B3. solenoid valve; A4 / B4. flow meter; A5 / B5. one-way valve; C. confluence valve. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0021] Example 1 A device for coating and CVD growth of carbon fiber electrode active materials, such as Figures 1 to 3As shown, it includes an array coating machine for preparing positive electrodes and a CVD equipment gas distribution system for preparing negative electrodes. The array coating machine includes a heating platform 6, a winding mechanism and a dispensing mechanism. The heating platform 6 is provided with an x-guide rail 1 and a y-guide rail 3. The x-guide rail 1 is arranged in parallel at the front and rear ends of the heating platform 6. The two ends of the y-guide rail 3 are respectively slidably arranged on the x-guide rail 1. The y-guide rail 3 is provided with an up-and-down moving mechanism 2. The up-and-down moving mechanism 2 includes an up-and-down moving slide rail 21. A cylinder 22 is arranged on the side of the up-and-down moving slide rail 21 facing the y-guide rail 3. A mounting plate 23 is arranged on the side of the up-and-down moving slide rail 21 facing the heating platform. A dispensing mechanism is arranged on the mounting plate. The dispensing mechanism adopts a single-liquid screw valve, including a barrel, a piezoelectric valve and a dispensing head. The amount of glue output is controlled by the piezoelectric valve. The dispensing mechanism can adopt a commercially available single-liquid screw valve.

[0022] The gas distribution system of the CVD equipment includes a gas A pipeline and a gas B pipeline. The gas A pipeline is provided with a gas pipe quick connector A1 at the gas inlet end, and a gas B pipeline is provided with a gas pipe quick connector B1 at the gas inlet end. The gas outlet end is connected in parallel to the main gas inlet pipeline through a confluence valve C. The gas A pipeline is provided with a manual ball valve A2, a solenoid valve A3, a flow meter A4 and a one-way valve A5 in sequence from the gas inlet end to the gas outlet end. The gas B pipeline is provided with a manual ball valve B2, a solenoid valve B3, a flow meter B4 and a one-way valve B5 in sequence from the gas inlet end to the gas outlet end.

[0023] The winding mechanism includes a winding wheel 51 and an unwinding wheel 52 arranged at both ends of the heating platform 6, a first guide rod 71 is arranged between the winding wheel 51 and the heating platform 6, and a second guide rod 72 is arranged between the unwinding wheel 52 and the heating platform. The maximum heating temperature of the heating platform 6 is 150°C, and the temperature control accuracy is ±1°C.

[0024] The flow meter A4 / B4 is a glass rotor flow meter.

[0025] When preparing the positive and negative electrode materials of lithium battery carbon fiber, the positive electrode is first prepared by coating the active material array on the surface of carbon fiber cloth 4, and the negative electrode is prepared by growing carbon nanotubes on the surface of carbon fiber cloth 4. The process requires heating at 500 ° C for 30 minutes in a tube furnace under Ar / NH3 flow (ammonia volume content 7%, flow rate: 80 mL / min). After cooling, 2 g of melamine is added to the porcelain boat, and the carbon fiber cloth is placed on top of the porcelain boat, and then heated to 850 ° C in an argon atmosphere (flow rate: 50 mL / min) for 2 hours.

[0026] The specific implementation methods are as follows: (1) A 3K carbon fiber cloth 4 with a width of 500 mm and a thickness of 0.2 mm is installed on the winding mechanism of the dot matrix coating machine, and it is ensured that the winding wheel 51 winds up enough carbon fiber cloth 4 to ensure the winding stepping motion during the coating process.

[0027] (2) Pour NCM811 slurry into the barrel of the dispensing mechanism of the dot matrix coating machine and keep it mixed evenly.

[0028] (3) According to Figure 4 The pattern shape shown is programmed, the coating area is a regular hexagon with a side length of 3 mm, and every six regular hexagons of the coating area surround a regular hexagon of the non-coating area. The coating amount is 0.6 mL / cm 2 , the distance between the piezoelectric valve and the heating platform is 2 mm.

[0029] (4) Set the temperature control temperature of the workbench to 120℃, and the piezoelectric valve will work after the temperature stabilizes.

[0030] (5) The winding device stops after each step of 500 mm, and the piezoelectric valve performs coating operations in an area of ​​500 mm × 500 mm.

[0031] (6) Prepare two gas cylinders with a pressure of 2 MPa. Cylinder A is filled with Ar / NH3 mixed gas, and cylinder B is filled with Ar gas. (7) Lead out two bottles of high-pressure gas through the adapter joint with 8mm PU tube, and connect them to the quick connectors A1 and B1 of the gas A pipeline and gas B pipeline of the gas supply device respectively, and keep the rear manual ball valve A2 / B2 closed; (8) Open the valves of gas cylinders A and B to allow the gas pressure in the cylinders to be added to the left end of the manual ball valve A2 / B2; (9) Flowmeter A4 / B4 is a special atmosphere flowmeter. When using different gas components, a special flow valve must be customized to ensure accurate control of the gas flow and maintain the corrosion resistance of the valve core. The present invention uses the LZB-WB glass rotor flowmeter of Nanjing Dahua Instrument, of which A4 is a special flowmeter for Ar / NH3 mixed gas and B4 is a special flowmeter for Ar gas. Before the equipment is turned on, keep the two flowmeters in the closed state.

[0032] (10) Press the start button of gas circuit A, then the solenoid valve A3 opens, the timed disconnection relay of gas circuit A starts, and the relay disconnection time is set. After setting, press the close button of gas circuit A, and the solenoid valve A3 closes.

[0033] (11) Press the start button of gas circuit B, then the solenoid valve B3 opens, the timed disconnection relay of gas circuit B starts, and the relay disconnection time is set. After setting, press the close button of gas circuit B, and the solenoid valve B3 closes.

[0034] (12) Operate the manual ball valve A2 to open it slightly, so that there is less gas flow capacity in the gas circuit A. Press the start button of the gas circuit A to open the solenoid valve A3. At this time, the gas pressure flows to the inlet of the flow meter A4.

[0035] (13) Slowly open the adjustment knob of flow meter A4 to adjust the flow rate to the process gas flow required. If the flow rate requirement cannot be met even if the knob is opened to a larger value, slightly increase the opening angle of manual ball valve A2 until the required flow rate is reached. At this time, gas supply to the CVD equipment has begun until the timing relay starts to cut off the gas supply. Manually close the control button of gas line A. (14) Operate the manual ball valve B2 to open it slightly, so that there is less gas flow capacity in gas path B. Press the start button of gas path B to open the solenoid valve B3. At this time, the gas pressure flows to the inlet of flow meter B4.

[0036] (15) Slowly open the adjustment knob of flow meter B3 to adjust the flow rate to the process gas flow rate required. If the flow rate requirement cannot be met even if the knob is opened to a larger value, slightly increase the opening angle of manual ball valve 7 until the required flow rate is reached. At this time, gas supply to the CVD equipment has begun until the timing relay starts to cut off the gas supply. Manually close the control button of gas line B. (16) When the timing of both gas supply lines ends, close the valves of gas cylinders A and B, turn off the power of the equipment, place the manual ball valves A2 and B2 in the cut-off position, and adjust the regulating valves of flow meters A4 and B4 to the closed state.

[0037] When the dot matrix coating is performed, the carbon fiber cloth 4 needs to be kept flat on the equipment, and the tension is provided by the winding device 5, and the winding device cooperates with the piezoelectric valve to perform winding in a step-by-step manner.

[0038] In order to improve the wettability of the coating material on the surface of the carbon fiber cloth 4, a heating platform 6 is installed on the dot matrix coating machine platform, and its maximum controlled temperature is 150°C, and the temperature control accuracy is ±1°C. When using the heating plate, the temperature tolerance range of the coating material should be strictly checked to prevent the coating material from failing due to excessive temperature.

[0039] The pipelines between manual ball valve A2 and solenoid valve A3, manual ball valve B2 and solenoid valve B3 use 1 / 2-inch 316 stainless steel pipelines. The pipelines between solenoid valve A3 and flow meter A4, solenoid valve B3 and flow meter B4 use a section of 1 / 2-inch 316 stainless steel pipeline. Install 316 material 1 / 2-inch internal thread 8mm pagoda connectors at the position of the pipeline close to flow meter A4 and flow meter B4, and use 8mm inner diameter silicone tubes with stainless steel pipe clamps to connect these two pagoda connectors to the pagoda inlets of flow meters A4 and B4; the outlets of flow meters A4 and B4 are connected. It is connected to the 316 material pagoda 1 / 2 inch external thread connector through an 8mm silicone tube and a tube clamp; the one-way valves A5 and B5 are tubular 1 / 2 inch internal thread 316 material one-way valves (the conduction pressure is 0.1MPa), and the conduction direction is from the gas cylinder to the CVD equipment. The air inlet ends of the two one-way valves are connected to the 316 material pagoda 1 / 2 inch external thread connector, and the air outlet ends are connected to the 316 material 1 / 2 inch external thread-8mm quick-plug connector; the outlet end of the one-way valve is connected to the 316 material quick-plug junction valve connector through an 8mmPU pressure-resistant air pipe, and the outlet of the junction valve C is connected to the CVD equipment through an 8mmPU tube.

[0040] The control panel on the front of the CVD equipment consists of the first gas circuit on / off switch, glass rotor flowmeter, timing control switch; the second gas circuit on / off switch, glass rotor flowmeter, timing control switch; the device main power switch, and emergency stop switch.

[0041] The gas inlet is on the left side of the CVD equipment, which is connected to gas cylinders of two atmospheres through two quick connectors. The on-off of the gas line is controlled by a manual ball valve and a solenoid valve.

[0042] The gas outlet is on the right side of the CVD equipment. Since the atmosphere is supplied separately, the gas that finally enters the CVD equipment is the gas in gas path A or gas path B. Therefore, the outlet uses a confluence valve to merge the two gases into one and pass them into the CVD equipment.

[0043] The CVD equipment has multiple layers of signal indicator lights to display the working status of the equipment. The green light indicates that the power is on, the red light indicates that gas line 1 is on, and the yellow light indicates that gas line 2 is on.

[0044] For the carbon fiber negative electrode with carbon nanotubes grown on it prepared by the above method of the same size, the same lithium ion structure energy storage composite material was prepared by intermittent coating with a coating machine and overall coating with 0.1mm thickness of active material NCM811 with a scraper. The interlayer shear strength of the composite sample prepared by the former was increased by 53.2% compared with the latter. The number of battery charge and discharge cycles was increased by 61% compared with the latter.

[0045] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A device for coating and CVD growth of carbon fiber electrode active materials, characterized in that: It comprises an array coating machine for preparing positive electrodes and a CVD equipment gas distribution system for preparing negative electrodes. The array coating machine comprises a heating platform, a winding mechanism and a dispensing mechanism. An x-guide rail and a y-guide rail are arranged on the heating platform. The x-guide rail is arranged in parallel at the front and rear ends of the heating platform. The two ends of the y-guide rail are respectively slidably arranged on the x-guide rail. An up-and-down moving mechanism is arranged on the y-guide rail. The up-and-down moving mechanism comprises an up-and-down moving slide rail. A cylinder is arranged on the side of the up-and-down moving slide rail facing the y-guide rail. A mounting plate is arranged on the side of the up-and-down moving slide rail facing the heating platform. The dispensing mechanism is arranged on the mounting plate. The CVD equipment gas distribution system comprises a gas A pipeline and a gas B pipeline. The gas inlet ends of the gas A pipeline and the gas B pipeline are respectively provided with gas pipe quick connectors. The gas outlet ends are connected in parallel to the main gas inlet pipeline through a confluence valve. The gas A pipeline and the gas B pipeline are sequentially provided with a manual ball valve, a solenoid valve, a flow meter and a one-way valve from the gas inlet end to the gas outlet end.

2. The device for coating and CVD growth of carbon fiber electrode active materials according to claim 1, characterized in that: The winding mechanism comprises a winding wheel and an unwinding wheel arranged at two ends of the heating platform, and guide rods are arranged between the winding wheel and the heating platform and between the unwinding wheel and the heating platform.

3. The device for coating and CVD growth of carbon fiber electrode active materials according to claim 1, characterized in that: The maximum heating temperature of the heating platform is 150°C, and the temperature control accuracy is ±1°C.

4. A method for coating carbon fibers with active substances and performing CVD growth using the device according to any one of claims 1 to 3, characterized in that: The process is as follows: (1) The substrate is mounted on the winding mechanism of the dot matrix coating machine, and the electrode active material slurry is poured into the barrel; (2) Determine the distance between the barrel and the heating platform according to the concentration of the slurry and the coating amount; (3) Programming is performed according to the pattern shape of the coating, and the heating temperature of the heating platform is set to perform coating and dispensing of the electrode active material. At the same time, the winding mechanism is wound until the coating is completed; (4) Place the raw materials containing the elements constituting the thin film into the porcelain boat of the quartz tube of the tubular furnace, place the substrate into the other end of the quartz tube, connect the quick connectors of the gas A pipeline and the gas B pipeline to the gas cylinder A and the gas cylinder B respectively, keep the manual ball valves on the gas A pipeline and the gas B pipeline closed, and connect the main air inlet pipeline to the gas supply end of the quartz tube through the connecting plug; (5) Press the start button of gas circuit A and / or gas circuit B, then the solenoid valve on gas pipeline A and / or gas pipeline B opens, the timed disconnection relay of gas circuit A and / or gas pipeline B starts, and the relay disconnection time is set. After the setting is completed, press the closing button of gas circuit A and / or gas circuit B, and the solenoid valve on gas pipeline A and / or gas pipeline B closes; (6) Operate the manual ball valve on the gas A pipeline and / or the gas B pipeline to open the manual ball valve slightly, so that there is less gas flow capacity in the gas line A and / or the gas line B. Press the start button of the gas line A and / or the gas line B to open the solenoid valve on the gas A pipeline and / or the gas B pipeline. At this time, the gas pressure flows to the inlet of the flow meter on the gas A pipeline and / or the gas B pipeline; (7) Turn on the adjustment knob of the flow meter on the gas A pipeline and / or the gas B pipeline to adjust the flow rate to the gas flow rate required by the process. If the flow rate requirement cannot be met even if the knob is turned to a larger value, increase the opening angle of the manual ball valve until the required flow rate is reached. At this time, gas supply to the CVD equipment has begun until the timing relay starts to cut off the gas supply. Manually close the control buttons of gas line A and gas line B. (8) When the timing of both gas supply is over, close the valves of gas cylinders A and B, turn off the power of the equipment, place the manual ball valves on the two gas pipelines in the cut-off position, and adjust the flow meter regulating valves on the two gas pipelines to the closed state.

5. The method according to claim 4, characterized in that In step (2), when the coating amount is ≤ 0.1 mL / cm 2 When the piezoelectric valve is at a distance of less than 1 mm from the surface of the heating platform, 2 ﹤Coating volume﹤0.5mL / cm 2 When the coating volume is 0.5mL / cm 2 When the pressure is above 200 °C, the distance between the piezoelectric valve and the surface of the heating platform should be controlled at 2 mm.

6. The method according to claim 4, characterized in that The substrates in step (1) and step (4) are both carbon fiber cloth.

7. The method according to claim 4, characterized in that The raw material containing the elements constituting the thin film refers to a raw material containing carbon.

Images