Photovoltaic carrier cleaning method and cleaning equipment applying micro-nano bubbles

Abstract

The invention discloses a photovoltaic carrier cleaning method applying micro-nano bubbles, and relates to the technical field of photovoltaics. According to the cleaning method, when the photovoltaic carrier is subjected to acid pickling, micro-nano bubbles are synchronously introduced into an acid pickling solution in an acid pickling tank, meanwhile, the concentration of the acid pickling solution put into the acid pickling tank is reduced to 40%-60% of an original acid pickling solution, or the acid pickling time is shortened to 40%-60% of the original acid pickling time. The invention further provides photovoltaic carrier cleaning equipment applying the micro-nano bubbles. According to the photovoltaic carrier cleaning method applying the micro-nano bubbles, the high specific surface area characteristic and the mass transfer effect of the micro-nano bubbles are applied, chemical reaction is accelerated, the photovoltaic carrier cleaning efficiency is improved, the dosage of chemicals in the cleaning process is reduced, the cleaning time is shortened, and the photovoltaic carrier cleaning efficiency is improved. And the consumption of chemicals, time and energy in the photovoltaic acid pickling process is reduced, and the productivity is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic technology, in particular to a cleaning method and cleaning equipment of a photovoltaic carrier using micro-nano bubbles. BACKGROUND

[0002] In the manufacturing process of photovoltaic cell components, graphite boats, quartz boats, graphite tubes, quartz tubes, etc. are usually used as specific photovoltaic carriers to support photovoltaic cell pieces to be coated. After several coating processes, a few microns of silicon-containing film layer will be deposited on the surface of the boat piece. If not cleaned in time, it will affect the film formation quality and appearance of subsequent other photovoltaic cell pieces, resulting in abnormal film thickness and even color difference, and the coating efficiency and quality are significantly reduced. In the prior art, mixed acid is usually used to clean the photovoltaic carrier. The cleaning process includes mixed acid washing, water washing, slow lifting, drying and other processes. The cleaning time of only the mixed acid washing step usually needs to last for several hours. The whole cleaning process not only requires a high concentration of mixed acid, but also has a relatively low efficiency. The chemical consumption is high, the cost of waste liquid treatment is relatively high, and the waste gas generated during the reaction process may pollute the environment, which often requires special pollution treatment measures, further increasing the cost of photovoltaic carrier cleaning. Therefore, it is urgent to find a more economical, efficient and environmentally friendly photovoltaic carrier cleaning method. SUMMARY

[0003] The main purpose of the present application is to provide a photovoltaic carrier cleaning method. The cleaning method introduces micro-nano bubbles in the acid washing process of the photovoltaic carrier. The micro-nano bubbles have the characteristics of large specific surface area, increased gas content in the acid washing liquid, and a large number of free radicals generated after the bubbles burst, which can accelerate the chemical reaction, reduce the amount of chemicals used in the acid washing process, shorten the acid washing time, and improve the cleaning efficiency of the photovoltaic carrier.

[0004] To achieve the above purpose, the present application provides a photovoltaic carrier cleaning method using micro-nano bubbles. The cleaning method includes: synchronously introducing micro-nano bubbles into the acid washing liquid of the acid washing tank according to a preset rule when the photovoltaic carrier is acid washed, and simultaneously reducing the concentration of the acid washing liquid put into the acid washing tank to a preset concentration; and / or synchronously introducing micro-nano bubbles into the acid washing liquid of the acid washing tank when the photovoltaic carrier is acid washed, and simultaneously shortening the acid washing time to a preset time.

[0005] Optionally, the preset concentration is 40-60% of the concentration of the acid washing liquid put into the acid washing tank when the photovoltaic carrier is acid washed without introducing micro-nano bubbles into the acid washing tank, and the preset time is 40-60% of the acid washing time consumed when the photovoltaic carrier is acid washed without introducing micro-nano bubbles into the acid washing tank.

[0006] Optionally, the diameter of the micro-nano bubbles simultaneously introduced into the pickling solution of the pickling tank is in the range of 10 nm-100 μm, and the particle concentration of the micro-nano bubbles in the pickling tank is 10 6 -10 9 μg / ml.

[0007] Optionally, the micro-nano bubbles comprise a single component gas and / or a mixed component gas.

[0008] Optionally, the gas in the micro-nano bubbles is a non-oxidizing gas.

[0009] Optionally, the gas in the micro-nano bubbles comprises an oxidizing gas.

[0010] Optionally, the gas in the micro-nano bubbles is one or more combinations of oxygen, ozone, air, nitrogen, and hydrogen.

[0011] Optionally, when the micro-nano bubbles are simultaneously introduced into the pickling solution of the pickling tank to perform pickling on the photovoltaic carrier, the pickling solution is a mixed pickling solution composed of hydrofluoric acid and hydrochloric acid; and / or, a mixed pickling solution composed of hydrofluoric acid and hydrogen peroxide; and / or, a mixed pickling solution composed of hydrofluoric acid and nitric acid.

[0012] Optionally, when the mixed pickling solution composed of hydrofluoric acid and hydrochloric acid is used as the pickling solution, the volume ratio of hydrofluoric acid to hydrochloric acid is in the range of 9:1 to 11:1.

[0013] Optionally, when the mixed pickling solution composed of hydrofluoric acid and hydrochloric acid is used as the pickling solution, the volume ratio of hydrofluoric acid to hydrochloric acid is 10:1.

[0014] Optionally, when the mixed pickling solution composed of hydrofluoric acid and nitric acid is used as the pickling solution, the volume ratio of hydrofluoric acid to nitric acid is in the range of 1:2-1:3.

[0015] Optionally, when the mixed pickling solution composed of hydrofluoric acid and nitric acid is used as the pickling solution, the volume ratio of hydrofluoric acid to nitric acid is 1:2.

[0016] Optionally, when the mixed pickling solution composed of hydrofluoric acid and hydrogen peroxide is used as the pickling solution, the volume ratio of hydrofluoric acid to hydrogen peroxide is in the range of 1:2-1:3.

[0017] Optionally, when the mixed pickling solution composed of hydrofluoric acid and hydrogen peroxide is used as the pickling solution, the volume ratio of hydrofluoric acid to hydrogen peroxide is 1:2.

[0018] Optionally, when the gas in the micro-nano bubbles comprises an oxidizing gas, the nitric acid in the mixed pickling solution is replaced or partially replaced by hydrogen peroxide.

[0019] Optionally, the preset rule comprises one or more factors of the micro-nano bubble concentration, the existence time of the micro-nano bubble, the concentration ratio of the micro-bubble and the nano-bubble in the micro-nano bubble, the content of the oxidizing gas in the micro-nano bubble and the oxidizing strength, the shape of the photovoltaic carrier, the size of the photovoltaic carrier, the volume of the photovoltaic carrier, whether to add one or more of the following auxiliary factors to the pickling process: heating, ultrasonic, stirring, oscillation, centrifugation, brushing, and additive, to affect the selection of the preset concentration and / or the determination of the preset time.

[0020] The application further provides a photovoltaic carrier cleaning device applying micro-nano bubbles.

[0021] The application provides a photovoltaic carrier cleaning method applying micro-nano bubbles, which applies the high specific surface area characteristics and mass transfer effect of the micro-nano bubbles to accelerate the chemical reaction, improve the photovoltaic carrier cleaning efficiency, reduce the chemical consumption in the cleaning process, shorten the cleaning time, and reduce the consumption of chemicals, time, and energy in the pickling process of the photovoltaic carrier, thereby greatly improving the production capacity. BRIEF DESCRIPTION OF DRAWINGS

[0022] The application will be described in detail below with reference to specific embodiments and drawings, in which:

[0023] Figure 1 The cleaning flowchart of the cleaning method of the silicon nitride graphite boat applying micro-nano bubbles provided in the first embodiment.

[0024] Figure 2 The cleaning flowchart of the cleaning method of the polysilicon graphite boat applying micro-nano bubbles provided in the second embodiment.

[0025] Figure 3 The cleaning flowchart of the cleaning method of the ordinary graphite boat / quartz boat / graphite tube / quartz tube applying micro-nano bubbles provided in the third embodiment. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme, and advantages of the application clearer, the application will be described in detail below with reference to the drawings and examples. It should be understood that the following specific examples are only used to explain the application and do not limit the application.

[0027] The application provides a photovoltaic carrier cleaning method using micro-nano bubbles, which comprises the following steps: synchronously introducing micro-nano bubbles into the acid washing liquid in the acid washing tank when the photovoltaic carrier is subjected to acid washing, and simultaneously reducing the concentration of the acid washing liquid in the acid washing tank and / or shortening the acid washing time. The micro-nano bubbles are bubbles with a diameter less than 100 microns, and the micro-nano bubbles have many characteristics that the traditional large bubbles do not have, including a large specific surface area, a high Zeta potential of the gas-liquid interface, an ability to increase the gas content in the solution, and an ability to generate a large amount of free radicals after the bubbles burst. As described above, a silicon-containing film layer with a thickness of several microns is deposited on the surface of the photovoltaic carrier, and micro-nano bubbles are synchronously introduced into the acid washing liquid in the acid washing tank during the acid washing process. The micro-nano bubbles with a large specific surface area can multiply the contact area between the acid washing liquid and the film layer on the surface of the photovoltaic carrier, the mass transfer characteristics of the acid washing liquid rich in micro-nano bubbles are significantly improved, and the reaction efficiency of the acid washing process is rapidly promoted due to the large amount of free radicals generated by the micro-nano bubbles after the bubbles burst. Therefore, the acid washing rate is significantly improved, and the same cleaning effect can be achieved by using a lower concentration of acid washing liquid or a shorter acid washing time than when no micro-nano bubbles are introduced. Therefore, it can be said that the synchronous introduction of micro-nano bubbles into the acid washing liquid in the acid washing tank can help to significantly improve the reaction rate, reduce the consumption of chemicals or time during the acid washing process of the photovoltaic carrier, and help to improve the production efficiency.

[0028] In specific implementation, the micro-nano bubbles can be introduced into the acid washing liquid in the form of internal circulation of the acid washing tank, that is, first, the acid washing liquid required for this acid washing is put into the acid washing tank, and then the internal circulation of the acid washing tank is started, the acid washing liquid is sent into a functional water generator, the functional water generator generates a large amount of micro-nano bubbles based on the acid washing liquid and mixes the micro-nano bubbles with the acid washing liquid, and then the photovoltaic carrier to be cleaned is put into the acid washing tank after the micro-nano bubbles and the acid washing liquid are fully mixed. Such an operation method is not only easy to operate and implement, but also can further avoid dilution of the original acid washing liquid after the functional water manufactured based on other solutions is introduced into the acid washing tank, so as to ensure that the concentration of the acid washing liquid in the acid washing process meets the reaction requirements. Alternatively, the functional water with a certain bubble concentration can be manufactured by the functional water generator, the functional water is a water-gas mixture in which micro-nano bubbles are introduced into water, the functional water is mixed with the prepared acid washing liquid, and the mixture is introduced into the acid washing tank to clean the photovoltaic carrier. Of course, if the above-mentioned functional water with water as the base is manufactured by the functional water generator, the technician should fully consider the volume of the water as the base in the functional water when preparing the acid washing liquid, so as to avoid that the excessive water in the functional water dilutes the concentration of the acid washing liquid when the functional water with water as the base is introduced into the acid washing tank, thereby hindering the reaction.

[0029] Optionally, when the micro-nano bubbles are synchronously introduced into the pickling solution of the pickling tank to pickling the photovoltaic carrier, the concentration of the pickling solution is reduced to 40%-60% of the concentration of the pickling solution without the micro-nano bubbles synchronously introduced into the pickling solution of the pickling tank to pickling the photovoltaic carrier. With the characteristics of the micro-nano bubbles, such as high specific surface area and a large number of free radicals generated after the bubbles burst, the same pickling effect as the traditional process can be achieved with 40%-60% of the concentration of the pickling solution used in the traditional process, greatly reducing the overall consumption of chemicals in the pickling process of the photovoltaic carrier.

[0030] Optionally, when the micro-nano bubbles are synchronously introduced into the pickling solution of the pickling tank to pickling the photovoltaic carrier, the pickling time is shortened to 40%-60% of the pickling time without the micro-nano bubbles synchronously introduced into the pickling solution of the pickling tank to pickling the photovoltaic carrier. Similarly, the micro-nano bubbles have the characteristics of high specific surface area and a large number of free radicals generated after the bubbles burst, which greatly help to promote the forward progress of the chemical reaction in the pickling process, significantly improve the efficiency of the pickling process, and achieve the same pickling effect as the traditional process with less pickling time in the traditional process, greatly reducing the time consumption of the pickling process of the photovoltaic carrier.

[0031] Optionally, the diameter of the micro-nano bubbles synchronously introduced into the pickling solution of the pickling tank is in the range of 10 nm-100 μm, and the particle concentration of the micro-nano bubbles in the pickling tank is 10 6 -10 9 μg / ml. The micro-nano bubbles in the range of 10 nm-100 μm have the characteristics of large specific surface area, high Zeta potential of gas-liquid interface, increased gas content in the solution, and a large number of free radicals generated after the bubbles burst. Taking a bubble as a calculation object, if the diameter of the bubble is r, the total volume is V, and the surface area is A; it is not difficult to calculate that the surface area of the bubble is: A=3V / r; it can be seen that for the micro-nano bubbles in the pickling solution, under the condition that the volume of the bubble is constant, the smaller the diameter of the bubble, the larger the surface area of the bubble, the smaller the particle, the higher the particle concentration, the larger the contact area of the pickling solution containing the micro-nano bubbles and the photovoltaic carrier to be pickled, and the more obvious the positive promotion effect on the chemical reaction, and the more obvious the improvement of the pickling efficiency.

[0032] Optionally, the gas in the micro-nano bubbles is a non-oxidizing gas. The micro-nano bubbles with non-oxidizing property do not participate in the specific chemical reaction in the pickling process of the photovoltaic carrier, but only act as a reaction booster to promote the forward progress of the reaction with the characteristics of high specific surface area and high mass transfer effect.

[0033] Optionally, the gas in the micro-nano bubbles is an oxidizing gas. The micro-nano bubbles with non-oxidizing properties will participate in the specific chemical reactions in the acid washing process of the photovoltaic carrier, help the free silicon ions in the acid washing solution to oxidize to form silicon dioxide and further react with the reactants such as hydrofluoric acid, and finally successfully strip the silicon-containing film layer on the surface of the photovoltaic carrier, or help the oxidation of other organic impurities on the surface of the photovoltaic carrier to achieve the expected cleaning goal. In specific implementation, the operator can select non-oxidizing gas and / or oxidizing gas as the specific gas in the micro-nano bubbles according to the specific composition of the film layer on the photovoltaic carrier to be cleaned.

[0034] Optionally, the micro-nano bubbles include single-component gas and / or mixed-component gas, and the gas in the micro-nano bubbles is one or more combinations of oxygen, ozone, air, nitrogen, and hydrogen. The specific gas can be a single gas with oxidizing or non-oxidizing properties, or a mixture of multiple gases in a certain proportion. The skilled person can select the appropriate gas source according to factors such as the cost of the gas source, the convenience of obtaining the gas source, the thickness of the film layer on the photovoltaic carrier to be cleaned, and the specific composition of the film layer on the photovoltaic carrier to be cleaned.

[0035] Optionally, when determining the concentration of the acid washing solution and / or the length of the acid washing time, the skilled person can determine the acid washing solution concentration and / or the acid washing time by considering factors such as the concentration of the micro-nano bubbles, the existence time of the micro-nano bubbles, the concentration ratio of the micron-sized bubbles to the nano-sized bubbles in the micro-nano bubbles, the content and oxidizing strength of the oxidizing gas in the micro-nano bubbles, and the like. The above factors related to the micro-nano bubbles in the functional water will directly determine the size of the positive promotion of the functional water to the chemical reaction, and the skilled person will consider the above factors to determine the specific numerical value of the acid washing solution concentration and / or the acid washing time, which can maximize the use of chemicals and save reaction time.

[0036] Optionally, when the micro-nano bubbles are simultaneously introduced into the acid washing solution in the acid washing tank to perform acid washing on the photovoltaic carrier, the acid washing solution is a mixed acid washing solution composed of hydrofluoric acid and hydrochloric acid; and / or, a mixed acid washing solution composed of hydrofluoric acid and hydrogen peroxide; and / or, a mixed acid washing solution composed of hydrofluoric acid and nitric acid.

[0037] Optionally, when the mixed acid washing solution composed of hydrofluoric acid and hydrochloric acid is used as the acid washing solution, the volume ratio of hydrofluoric acid to hydrochloric acid is in the range of 9:1 to 11:1.

[0038] Optionally, when the mixed acid washing solution composed of hydrofluoric acid and hydrochloric acid is used as the acid washing solution, the volume ratio of hydrofluoric acid to hydrochloric acid is 10:1.

[0039] Optionally, when the mixed acid washing solution composed of hydrofluoric acid and nitric acid is used as the acid washing solution, the volume ratio of hydrofluoric acid to nitric acid is in the range of 1:2-1:3.

[0040] Optionally, when the mixed acid pickling solution is composed of hydrofluoric acid and nitric acid, the volume ratio of hydrofluoric acid to nitric acid is 1:2.

[0041] Optionally, when the mixed acid pickling solution is composed of hydrofluoric acid and hydrogen peroxide, the volume ratio of hydrofluoric acid to hydrogen peroxide is in the range of 1:2-1:3.

[0042] Optionally, when the mixed acid pickling solution is composed of hydrofluoric acid and hydrogen peroxide, the volume ratio of hydrofluoric acid to hydrogen peroxide is 1:2.

[0043] Optionally, when the gas in the micro-nano bubbles contains oxidizing gas, hydrogen peroxide replaces or partially replaces nitric acid in the mixed acid pickling solution. Nitric acid has strong oxidizing properties. For example, when the gas in the micro-nano bubbles contains oxygen, ozone, air, or other oxidizing gases, the micro-nano bubbles will react with the silicon-containing film layer on the surface of the photovoltaic carrier when the oxidizing gas in the bubbles contacts the photovoltaic carrier, causing the silicon-containing film layer to be oxidized into silicon dioxide or other silicon-containing compounds that are easily reacted with hydrofluoric acid. In this process, the oxidizing gas in the micro-nano bubbles plays a certain degree of oxidation. Therefore, when the gas in the micro-nano bubbles contains oxidizing gas, depending on the strength of the oxidizing gas itself and the concentration of the micro-nano bubbles, hydrogen peroxide can partially or completely replace nitric acid in the original mixed acid pickling solution, reducing the concentration of nitric acid in the original mixed acid pickling solution or even not using nitric acid at all. By replacing or partially replacing nitric acid with hydrogen peroxide, the cleaning effect is guaranteed, and the production of nitrogen-containing compounds after the reaction of nitric acid is reduced, making the pickling process more environmentally friendly and reducing the difficulty of treating waste gas or wastewater.

[0044] Optionally, when determining the concentration of the pickling solution and / or the length of the pickling time, for a specific photovoltaic carrier to be cleaned, the technician can determine the pickling solution concentration and / or the pickling time by considering the shape of the photovoltaic carrier, the size of the photovoltaic carrier, the volume of the photovoltaic carrier, and other factors, to avoid affecting the cleaning effect due to differences in the specific size of the photovoltaic carrier.

[0045] Optionally, in the specific acid washing process, the acid washing liquid and / or the photovoltaic carrier can be subjected to an auxiliary cleaning process, and the specific auxiliary cleaning process includes adding heating assistance, ultrasonic assistance, stirring assistance, oscillation assistance, centrifugal assistance, brushing assistance, and additive assistance in the acid washing liquid to the acid washing process. When determining the concentration of the acid washing liquid and / or the length of the acid washing time, the technical personnel can determine the acid washing liquid concentration and / or the acid washing time by comprehensively considering the heating time, the heating temperature, the ultrasonic frequency, the stirring degree, the oscillation frequency, the centrifugal speed, the brushing frequency, the brush head size, the brush head material, the additive concentration, the additive type, and other factors based on the above-mentioned auxiliary cleaning process measures, and comprehensively considering the influence of the auxiliary cleaning process measures on the acid washing process to help reduce the amount of chemicals used in the acid washing process as much as possible and shorten the time consumed in the acid washing process.

[0046] The application also provides a photovoltaic carrier cleaning device applying micro-nano bubbles.

[0047] The following is a specific embodiment of applying the cleaning method of the silicon nitride graphite boat applying micro-nano bubbles to a specific photovoltaic carrier cleaning scene. Specific embodiment one

[0049] In this specific embodiment, a cleaning method of a silicon nitride graphite boat applying micro-nano bubbles is provided, which includes the following steps:

[0050] S11: Put a mixed acid liquid composed of hydrofluoric acid and hydrochloric acid into the acid washing tank, and adjust the concentration of the mixed acid liquid in the acid washing tank to 40% of the concentration of the original mixed acid liquid used in the prior art silicon nitride graphite boat acid washing process;

[0051] S12: Acid washing: Place the silicon nitride graphite boat to be cleaned in the cleaning carrier, use the cleaning robot to grip the cleaning carrier, immerse the silicon nitride graphite boat in the acid washing tank, use oxygen as the gas source, use the micro-nano bubble water generator to introduce micro-nano bubbles into the acid washing liquid in the acid washing tank to start acid washing, the diameter of the micro-nano bubbles introduced into the acid washing tank is in the range of 10 nm-100 μm, the particle concentration of the micro-nano bubbles in the acid washing tank is 10 6 -10 9 μg / ml, maintain the acid washing temperature at room temperature, and the acid washing time is 350 minutes; in this step, the reaction occurring in the acid washing tank is: Si3N4+12HF→3SiF4↑+4NH3↑; (in the formula, ↑ represents gas)

[0052] S13: water washing: the cleaning robot gripped the cleaning carrier, and the silicon nitride graphite boat was taken out of the acid washing tank and placed into the first water washing tank. The pure water was sprayed to remove the residual chemical liquid on the surface of the graphite boat. The rinsing temperature was room temperature, and the rinsing time was 30 minutes.

[0053] S14: water washing: the cleaning robot gripped the cleaning carrier, and the silicon nitride graphite boat was taken out of the first water washing tank and placed into the second water washing tank. The pure water was overflowed to remove the residual chemical liquid on the surface of the graphite boat. The rinsing temperature was room temperature, and the rinsing time was 260 minutes.

[0054] S15: slow lifting: the cleaning robot gripped the cleaning carrier, and the silicon nitride graphite boat was taken out of the second water washing tank and sent into the slow lifting tank to perform the pre-dewatering treatment before drying.

[0055] S16: drying: the cleaning robot gripped the cleaning carrier, and the silicon nitride graphite boat was sent into the drying tank. The drying time was 90 minutes. Specific embodiment two

[0057] In the specific embodiment, a cleaning method of a polysilicon graphite boat using micro-nano bubbles is provided, which includes the following steps:

[0058] S21: a mixed acid liquid composed of hydrofluoric acid and nitric acid is placed in the first acid washing tank. The concentration of the mixed acid liquid in the first acid washing tank is the same as that of the original mixed acid liquid used in the existing silicon nitride graphite boat acid washing process.

[0059] S22: acid washing: the polysilicon graphite boat to be cleaned is placed in the cleaning carrier. The cleaning robot grips the cleaning carrier, and the polysilicon graphite boat is immersed in the first acid washing tank. Oxygen is used as the gas source, and the micro-nano bubble water generator is used to introduce micro-nano bubbles into the first acid washing tank to start the acid washing. The diameter of the micro-nano bubbles introduced into the acid washing tank is in the range of 10 nm-100 μm. The particle concentration of the micro-nano bubbles in the acid washing tank is 10 6 -10 9 μg / ml. The acid washing temperature is room temperature, and the acid washing time is shortened to 120 minutes. In this step, the reactions in the first acid washing tank are as follows:

[0060] 2Si + 2O2→ 2SiO2;

[0061] 3Si + 4HNO3→ 3SiO2+ 4NO↑+ 2H2O;

[0062] SiO2+ 4HF→ SiF4↑+ 2H2O;

[0063] (In the above formula, ↑ represents gas)

[0064] S23: water washing: the cleaning robot grips the cleaning carrier, and the polycrystalline silicon graphite boat is taken out of the first acid washing tank and placed in the first water washing tank. The pure water overflow method is used to remove the residual liquid medicine on the surface of the polycrystalline silicon graphite boat in the first water washing tank. The rinsing temperature is room temperature, and the rinsing time is 30 minutes;

[0065] S24: acid washing: the second acid washing tank is filled with a mixed acid liquid composed of hydrofluoric acid and hydrochloric acid. The cleaning robot grips the cleaning carrier, and the polycrystalline silicon graphite boat is taken out of the first water washing tank and immersed in the second acid washing tank to start acid washing. The acid washing temperature is room temperature, and the acid washing time is 240 minutes. In this step, the second acid washing tank reacts as follows: SiO2 + 4HF → SiF4↑ + 2H2O (in the formula, ↑ represents gas)

[0066] S25: water washing: the cleaning robot grips the cleaning carrier, and the polycrystalline silicon graphite boat is taken out of the second acid washing tank and placed in the second water washing tank. The pure water overflow method is used to remove the residual liquid medicine on the surface of the polycrystalline silicon graphite boat in the second water washing tank. The rinsing temperature is room temperature, and the rinsing time is 30 minutes;

[0067] S26: slow pulling: the cleaning robot grips the cleaning carrier, and the polycrystalline silicon graphite boat is taken out of the second water washing tank and sent to the slow pulling tank for pre-dewatering treatment before drying.

[0068] S27: drying: the cleaning robot grips the cleaning carrier, and the polycrystalline silicon graphite boat is sent to the drying tank. The drying time is 90 minutes. THIRD EMBODIMENT

[0070] In this embodiment, a cleaning method for ordinary graphite boats / quartz boats / graphite tubes / quartz tubes using micro-nano bubbles is provided, which includes the following steps:

[0071] S31: a mixed acid liquid composed of hydrofluoric acid and hydrochloric acid is placed in the acid washing tank. The concentration of the mixed acid liquid in the acid washing tank is adjusted to be 40% of the concentration of the original mixed acid liquid used in the prior art silicon nitride graphite boat acid washing process.

[0072] S32: acid washing: the ordinary graphite boat / quartz boat / graphite tube / quartz tube to be cleaned is placed in the cleaning carrier. The cleaning robot grips the cleaning carrier and immerses the ordinary graphite boat / quartz boat / graphite tube / quartz tube in the acid washing tank. Oxygen is used as the gas source, and a micro-nano bubble water generator is used to introduce micro-nano bubbles into the acid washing liquid in the acid washing tank to start acid washing. The diameter of the micro-nano bubbles introduced into the acid washing tank is in the range of 10 nm-100 μm. The particle concentration of the micro-nano bubbles in the acid washing tank is 10 6 -10 9 mg / L. The acid washing temperature is room temperature, and the acid washing time is 350 minutes.

[0073] S33: water washing: the cleaning robot grips the cleaning carrier, takes the ordinary graphite boat / quartz boat / graphite tube / quartz tube out of the acid washing tank and puts it into the first water washing tank, removes the residual chemical liquid on the surface of the ordinary graphite boat / quartz boat / graphite tube / quartz tube in the first water washing tank by pure water spraying, keeps the rinsing temperature at room temperature, and rinses for 30 minutes;

[0074] S34: water washing: the cleaning robot grips the cleaning carrier, takes the ordinary graphite boat / quartz boat / graphite tube / quartz tube out of the first water washing tank and puts it into the second water washing tank, removes the residual chemical liquid on the surface of the ordinary graphite boat / quartz boat / graphite tube / quartz tube in the second water washing tank by pure water overflow, keeps the rinsing temperature at room temperature, and rinses for 30 minutes;

[0075] S35: slow lifting: the cleaning robot grips the cleaning carrier, takes the ordinary graphite boat / quartz boat / graphite tube / quartz tube out of the second water washing tank and puts it into the slow lifting tank to perform pre-drying treatment on the ordinary graphite boat / quartz boat / graphite tube / quartz tube;

[0076] S36: drying: the cleaning robot grips the cleaning carrier, takes the ordinary graphite boat / quartz boat / graphite tube / quartz tube out of the second water washing tank and puts it into the drying tank, and dries for 90 minutes.

[0077] The above cleaning method of the ordinary graphite boat / quartz boat / graphite tube / quartz tube using micro-nano bubbles is compared with the amount of chemicals used and the acid washing time in the conventional process without using functional water in the prior art. The comparison is shown in Table 1:

[0078]

[0079] (Table 1)

[0080] (Note: In Table 1, the chemical liquid concentration of HF used in the conventional process is the same as that of HF used in the micro-nano bubble process; the chemical liquid concentration of HCL used in the conventional process is the same as that of HCL used in the micro-nano bubble process)

[0081] As shown in Table 1, to realize the cleaning of ordinary graphite boat / quartz boat / graphite tube / quartz tube, the conventional process in the prior art does not apply micro-nano bubbles, and uses hydrofluoric acid and hydrochloric acid to prepare an acid cleaning solution in a ratio of 10:1, wherein the hydrofluoric acid is 550L, the hydrochloric acid is 55L, and the acid cleaning time is 350 minutes; while the cleaning method applying micro-nano bubbles provided in the embodiment also uses hydrofluoric acid and hydrochloric acid to prepare an acid cleaning solution in a ratio of 10:1, wherein the hydrofluoric acid is 330L, which is 60% of the amount of hydrofluoric acid in the conventional process, the hydrochloric acid is 33L, which is 60% of the amount of hydrochloric acid in the conventional process, and the cleaning performance comparison data of the two groups of photovoltaic carriers after cleaning of the ordinary graphite boat / quartz boat / graphite tube / quartz tube are shown in Table 2:

[0082] Type Eta Uoc Isc FF Rs Rsh Irev2 Qty Conventional process (before experiment) 26.619％ 0.7374 14.106 85.65 0.00149 3128 0.040 1761 Functional water process (experimental group) 26.622％ 0.7373 14.106 85.68 0.00148 3097 0.048 1128 Conventional process (after experiment) 26.588％ 0.7379 14.101 85.52 0.00151 3088 0.050 1064

[0083] (Table 2)

[0084] In Table 2, Qty is the number of photovoltaic cell pieces; Eta is the conversion efficiency; Uoc is the open circuit voltage, unit: volt; Isc is the short circuit current, unit: ampere; FF is the fill factor; Rs is the contact resistance, unit: ohm; Rsh is the parallel resistance, unit: ohm; Irev2 is the leakage current, unit: ampere.

[0085] It can be clearly seen from Table 1 and Table 2 that the appearance and electrical performance data of the ordinary graphite boat / quartz boat / graphite tube / quartz tube cleaned by the cleaning method applying micro-nano bubbles in the embodiment are normal, which meets the requirements of mass production of graphite boat cleaning. Embodiment Four

[0087] In the embodiment, a cleaning method of ordinary graphite boat / quartz boat / graphite tube / quartz tube applying micro-nano bubbles is provided, which comprises the following steps:

[0088] S41: Compared with the conventional process using hydrofluoric acid and nitric acid to form a mixed acid cleaning solution, in the embodiment, a mixed acid solution composed of hydrofluoric acid and hydrogen peroxide is put into the acid cleaning tank;

[0089] S42: Acid cleaning: placing the ordinary graphite boat / quartz boat / graphite tube / quartz tube to be cleaned in the cleaning carrier, using the cleaning robot to grip the cleaning carrier, immersing the ordinary graphite boat / quartz boat / graphite tube / quartz tube into the acid cleaning tank, using oxygen as the gas source, using the micro-nano bubble water generator to introduce micro-nano bubbles into the acid cleaning solution in the acid cleaning tank to start acid cleaning, the diameter of the micro-nano bubbles introduced into the acid cleaning tank is in the range of 10nm-100μm, and the particle concentration of the micro-nano bubbles in the acid cleaning tank is 10 6 -10 9g / ml, the pickling temperature is room temperature, and the pickling time is 320 minutes;

[0090] S43: water washing: the cleaning robot grips the cleaning carrier, takes the ordinary graphite boat / quartz boat / graphite tube / quartz tube out of the pickling tank and puts it into the first water washing tank, removes the residual liquid medicine on the surface of the ordinary graphite boat / quartz boat / graphite tube / quartz tube in the first water washing tank through pure water spraying, keeps the rinsing temperature at room temperature, and rinses for 30 minutes;

[0091] S44: water washing: the cleaning robot grips the cleaning carrier, takes the ordinary graphite boat / quartz boat / graphite tube / quartz tube out of the first water washing tank and puts it into the second water washing tank, removes the residual liquid medicine on the surface of the ordinary graphite boat / quartz boat / graphite tube / quartz tube in the second water washing tank through pure water overflow, keeps the rinsing temperature at room temperature, and rinses for 30 minutes;

[0092] S45: slow lifting: the cleaning robot grips the cleaning carrier, takes the ordinary graphite boat / quartz boat / graphite tube / quartz tube out of the second water washing tank and puts it into the slow lifting tank to perform pre-drying treatment on the ordinary graphite boat / quartz boat / graphite tube / quartz tube;

[0093] S46: drying: the cleaning robot grips the cleaning carrier, takes the ordinary graphite boat / quartz boat / graphite tube / quartz tube out of the second water washing tank and puts it into the drying tank, and dries for 90 minutes.

[0094] The cleaning method of the ordinary graphite boat / quartz boat / graphite tube / quartz tube using micro-nano bubbles is compared with the chemical use and pickling time in the conventional process using a mixed acid pickling solution composed of hydrofluoric acid and nitric acid in the prior art. The comparison is shown in Table Three:

[0095]

[0096] (Table Three)

[0097] As shown in Table Three, to clean the ordinary graphite boat / quartz boat / graphite tube / quartz tube, micro-nano bubbles are not used in the conventional process, and hydrofluoric acid and nitric acid are used to prepare the pickling solution at a volume ratio of 1:2, wherein 137L of hydrofluoric acid and 274L of hydrochloric acid are used, and the pickling time is 320 minutes. In the cleaning method using micro-nano bubbles provided in the embodiment, micro-nano bubbles are used, hydrofluoric acid and hydrogen peroxide are used to prepare the pickling solution at a ratio of 1:2, wherein 137L of hydrofluoric acid is used, which is the same as the amount of hydrofluoric acid used in the conventional process, 274L of hydrogen peroxide is used, and nitric acid is not used in the micro-nano bubble process, but is replaced by hydrogen peroxide.

[0098] From the comparison of the above conventional process and the micro-nano bubble process, it can be clearly known that the micro-nano bubbles generated by oxygen will have certain oxidation ability, and will assist the common oxidation of the silicon-containing film layer by hydrogen peroxide with weak oxidation ability. The above method of using oxygen micro-nano bubbles and hydrogen peroxide for combined pickling can completely replace the method of nitric acid in the conventional process. No nitrogen compounds such as nitric oxide are generated in the hydrogen peroxide reaction process, the pickling process is more environmentally friendly, and the treatment difficulty of waste gas or waste water is greatly reduced.

[0099] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made under the inventive concept of the present application, using the content of the present application specification and drawings, or directly / indirectly applied in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A photovoltaic carrier cleaning method using micro-nano bubbles, characterized in that: The cleaning method includes: when pickling the photovoltaic carrier, micro-nano bubbles are simultaneously introduced into the pickling liquid in the pickling tank, and the concentration of the pickling liquid added to the pickling tank is reduced to a preset concentration according to preset rules; and / or, when pickling the photovoltaic carrier, micro-nano bubbles are simultaneously introduced into the pickling liquid in the pickling tank, and the pickling time is shortened to a preset time according to preset rules.

2. The photovoltaic carrier cleaning method using micro-nano bubbles according to claim 1, characterized in that: The preset concentration is 40%-60% of the concentration of the pickling solution when micro-nano bubbles are not introduced into the pickling tank to pickle the photovoltaic carrier, and the preset time is 40-60% of the pickling time consumed when micro-nano bubbles are not introduced into the pickling tank to pickle the photovoltaic carrier.

3. The photovoltaic carrier cleaning method using micro-nano bubbles according to claim 1, characterized in that: The diameter of the micro-nano bubbles introduced into the pickling liquid of the pickling tank is in the range of 10nm-100μm, and the particle concentration of the micro-nano bubbles in the pickling tank is 10 6 -10 9 particles / ml.

4. The photovoltaic carrier cleaning method using micro-nano bubbles according to claim 2, wherein: The micro-nano bubbles include single-component gas and / or mixed-component gas.

5. The photovoltaic carrier cleaning method using micro-nano bubbles according to claim 4, characterized in that: The gas in the micro-nano bubbles includes non-oxidizing gas and / or oxidizing gas.

6. The photovoltaic carrier cleaning method using micro-nano bubbles according to claim 1, characterized in that: When micro-nano bubbles are introduced into the pickling liquid of the pickling tank to pickle the photovoltaic carrier, the pickling liquid includes a mixed acid composed of hydrofluoric acid and one or more combinations of hydrochloric acid, nitric acid, and hydrogen peroxide.

7. The photovoltaic carrier cleaning method using micro-nano bubbles according to claim 6, characterized in that: When a mixed pickling solution composed of hydrofluoric acid and hydrochloric acid is used as the pickling solution, the volume ratio of hydrofluoric acid to hydrochloric acid is in the range of 9:1 to 11:1; when a mixed pickling solution composed of hydrofluoric acid and nitric acid is used as the pickling solution, the volume ratio of hydrofluoric acid to nitric acid is in the range of 1:2-1:3; when a mixed pickling solution of hydrofluoric acid and hydrogen peroxide is used as the pickling solution, the volume ratio of hydrofluoric acid to hydrogen peroxide is in the range of 1:2-1:

3.

8. The photovoltaic carrier cleaning method using micro-nano bubbles according to claim 7, characterized in that: When the gas in the micro-nano bubbles contains an oxidizing gas, the nitric acid in the mixed pickling solution is replaced or partially replaced by hydrogen peroxide.

9. The photovoltaic carrier cleaning method using micro-nano bubbles according to any one of claims 1 to 8, characterized in that: The preset rules include the influence of one or more factors including the concentration of micro-nano bubbles, the existence time of micro-nano bubbles, the concentration ratio of micron-sized bubbles to nano-sized bubbles in micro-nano bubbles, the content of oxidizing gas in micro-nano bubbles and the strength of its oxidizing property, the shape of the photovoltaic carrier, the size of the photovoltaic carrier, the volume of the photovoltaic carrier, and whether to add heating assistance, ultrasonic assistance, stirring assistance, oscillation assistance, centrifugal assistance, brushing assistance, and additive assistance to the pickling process to select the preset concentration and / or determine the preset time.

10. A photovoltaic carrier cleaning device using micro-nano bubbles, characterized in that: The device uses the photovoltaic carrier cleaning method using micro-nano bubbles as described in any one of claims 1-9.

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