Method for solving texturing white spots of TOPCon battery

Abstract

The invention discloses a method for solving texturing white spots of a TOPCon battery, and the method comprises the following operation steps: pre-cleaning: employing a deepening pre-cleaning mode to remove organic pollution and part of a mechanical damage layer on the surface of a silicon wafer; washing: washing desorbed impurities and residual alkali liquor on the surface with deionized water; post-cleaning: removing some organic matters in the additive remaining on the surface of the silicon wafer; washing: washing desorbed impurities and residual alkali liquor on the surface with deionized water; hydrofluoric acid and hydrochloric acid are mixed for pickling, so that alkali residues are neutralized, and the dehydration effect is improved. According to the method for solving the texturing white spots of the TOPCon battery, the pre-cleaning step and the water cleaning step of an existing Topcon battery in the texturing process are optimized, and the texturing production requirement of the Topcon battery can be met through the process, so that the effects of batch production of high-resistance silicon wafers of the Topcon battery and improvement of the conversion efficiency of the battery are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of Topcon battery production, and particularly relates to a method for solving the problem of texture white spots in TOPCon batteries. Background Art

[0002] The method for solving the texture white spots in TOPCon batteries is a method for overcoming the problem of white spots in the texture process of high-resistance silicon wafers during the production process. With the continuous development of new energy technologies, the utilization of renewable energy such as solar energy is becoming more and more widespread. As an important energy conversion device, solar cells play a crucial role in the photovoltaic system. The quality of solar cells directly affects the energy conversion efficiency and operation stability of the entire system. Topcon solar cells have higher cell conversion efficiency, lower production costs, and better technological breakthroughs. In the process of improving the efficiency of Topcon batteries, how to effectively overcome the technical problem of white spots in the texture process of high-resistance silicon wafers during the production process, and how to effectively reduce the texture white spots in the production of Topcon batteries are issues that need to be deeply studied and urgently solved.

[0003] The existing method for solving the texture white spots in TOPCon batteries has certain drawbacks when in use. For the problem of white spots in the texture process of silicon wafers: every time high-resistance silicon wafers are produced, the white spots in the texture process are very serious, accounting for 0.53% (less than 0.02% for conventional silicon wafers). Even when changing the process formula and increasing the dosage of pre-cleaning chemicals in the production of silicon wafers and batteries, the phenomenon of texture white spots cannot be completely solved. Therefore, it is urgent to solve the problem of white spots in the texture process of high-resistance silicon wafers. For the problem of white spots in the texture process of high-resistance silicon wafers, in the production of segmented silicon wafer cleaning, increasing the dosage of chemicals, adjusting the cleaning time, increasing the overflow rate, and shortening the liquid change frequency are used to solve the problem of white spots in the texture process of batteries (the effect is not obvious). The main impacts of the above solutions are as follows: ① The unit consumption of cleaning chemicals increases by 83.33%; ② The cleaning power consumption increases by 21.57%; ③ The cleaning water consumption increases by 37.34%; ④ The production cost increases. In the texture process of the battery section, increasing the dosage of chemicals is used to solve the problem of white spots in the texture process of batteries (it has an effect but cannot completely solve the problem). The main impacts of the above solutions are as follows: ① The amount of sodium hydroxide and hydrogen peroxide increases. Therefore, we propose a method for solving the texture white spots in TOPCon batteries. Summary of the Invention

[0004] Technical problem to be solved: Aiming at the deficiencies of the prior art, the present invention provides a method for solving the texture white spots in TOPCon batteries, which optimizes the pre-cleaning and water cleaning steps in the texture process of existing Topcon batteries. Through this process, the production requirements of Topcon battery texture can be met, so as to achieve the mass production of high-resistance silicon wafers for Topcon batteries and improve the effect of battery conversion efficiency, and can effectively solve the problems in the background art.

[0005] Technical solution: To achieve the above object, the technical solution adopted by the present invention is as follows: A method for solving the white spots in the texturing of TOPCon cells, comprising the following operating steps: S1: Pre-cleaning: Adopt the method of deepening pre-cleaning to remove the organic matter pollution and part of the mechanical damage layer on the surface of the silicon wafer; S2: Water washing: Rinse the impurities and residual alkali solution that have been desorbed on the surface with deionized water; S3: Post-cleaning: Remove some organic substances in the additives remaining on the surface of the silicon wafer; S4: Water washing: Rinse the impurities and residual alkali solution that have been desorbed on the surface with deionized water; S5: Acid washing: Mix and acid wash with hydrofluoric acid and hydrochloric acid to neutralize the alkali residue and increase the dehydration effect; S6: Water washing: Rinse the impurities and residual acid solution that have been desorbed on the surface with deionized water; S7: Pre-dehydration: Pre-dehydrate the silicon wafer by using the method of slow lifting.

[0006] As a preferred technical solution of the present application, the bubbling in the pre-cleaning in step S1 has a pressure of 0.2-0.5 Mpa, the bubbling in the pre-cleaning has a flow rate of 1-1.5 m³ / h, the temperature of the pre-cleaning is 70±5°C, and the cleaning time is 220 s.

[0007] As a preferred technical solution of the present application, the temperature of the cleaning in step S2 is room temperature, and the cleaning time is 120 s.

[0008] As a preferred technical solution of the present application, the temperature of the post-cleaning in step S3 is 68±5°C, and the cleaning time is 100 s.

[0009] As a preferred technical solution of the present application, the temperature of the cleaning in step S4 is room temperature, and the cleaning time is 100 s.

[0010] As a preferred technical solution of the present application, the temperature of the cleaning in step S5 is room temperature, and the cleaning time is 100 s.

[0011] As a preferred technical solution of the present application, the temperature of the cleaning in step S6 is room temperature, and the cleaning time is 100 s.

[0012] As a preferred technical solution of the present application, the temperature of the post-cleaning in step S7 is 78±5°C, the cleaning time is 10 s, the lifting speed used for slow lifting is 0~5 mm / s, and after pre-dehydration, the silicon wafer is thoroughly dried by high temperature in an oven. The drying temperature of the oven is 95±5°C, and the time is 600 s.

[0013] As a preferred technical solution of the present application, a temperature and white spot monitoring system is provided in the steps S1 - S7. The temperature and white spot monitoring system includes a temperature sensor, a white spot detection SEM camera, a communication module, a central processor, a display, a temperature controller and an alarm. The temperature sensor and the white spot detection SEM camera are both connected to the communication module, the communication module is connected to the central processor, and the central processor is connected to the display, the temperature controller and the alarm.

[0014] As a preferred technical solution of the present application, the output ends of the temperature sensor and the white spot detection SEM camera are electrically connected to the input end of the communication module, the output end of the communication module is electrically connected to the input end of the central processor, and the output end of the central processor is electrically connected to the input ends of the display, the temperature controller and the alarm.

[0015] Beneficial effects: Compared with the prior art, the present invention provides a method for solving the white spots in the texturing of TOPCon batteries, and has the following beneficial effects: The method for solving the white spots in the texturing of TOPCon batteries optimizes the pre - cleaning and water - cleaning steps in the texturing process of existing Topcon batteries. Through this process, the production requirements of Topcon battery texturing can be met, so as to achieve the mass production of high - resistance silicon wafers for Topcon batteries and improve the battery conversion efficiency. By increasing the pressure of the overflow bubbling in the pre - cleaning tank process of the front cleaning tank and reducing the flow rate of the bubbling, the penetration power of the bubbling is enhanced, and the water - cleaning temperature of the front cleaning tank is increased. Through the above measures, the activity of the liquid medicine is improved. Through the adjustment of the above - mentioned core processes, the pre - cleaning effect of the silicon wafers in the texturing process is improved, and the proportion of white spots drops from 0.53% in the experiment to below 0.02%. Through the adjustment of process parameters, the breakthrough of white spots in the texturing blanking of Topcon batteries can be achieved, and the comprehensive yield of Topcon battery wafers is improved. The entire method for solving the white spots in the texturing of TOPCon batteries has a simple structure, is easy to operate, and has a better use effect compared with the traditional method. Description of the Drawings

[0016] Figure 1 It is a schematic diagram of the overall structure of a method for solving the white spots in the texturing of TOPCon batteries according to the present invention.

[0017] Figure 2 It is a schematic diagram of the structure of Embodiment Scheme 1 in a method for solving the white spots in the texturing of TOPCon batteries according to the present invention.

[0018] Figure 3 It is a schematic diagram of the structure of Embodiment Scheme 2 in a method for solving the white spots in the texturing of TOPCon batteries according to the present invention.

[0019] Figure 4This is a schematic structural diagram of the experimental data of an embodiment in a method for solving the texturing white spots of TOPCon cells according to the present invention.

[0020] Figure 5 This is a schematic structural diagram of the data comparison before and after improvement in a method for solving the texturing white spots of TOPCon cells according to the present invention.

[0021] Figure 6 This is a schematic diagram of the degradation trend of texturing white spots in a method for solving the texturing white spots of TOPCon cells according to the present invention. Detailed implementation manners

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific implementation manners. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention. Those not specified in the embodiments are carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase.

[0023] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0024] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0025] As Figure 1-6 shown, a method for solving the texturing white spots of TOPCon cells includes the following operation steps: S1: Pre-cleaning: Adopt the method of deepening pre-cleaning to remove the organic contamination and part of the mechanical damage layer on the surface of the silicon wafer; S2: Water washing: Rinse the desorbed impurities and residual lye on the surface with deionized water; S3: Post - cleaning: Remove some organic substances in the additives remaining on the silicon wafer surface; S4: Water washing: Rinse the desorbed impurities and residual lye on the surface with deionized water; S5: Acid pickling: Use a mixture of hydrofluoric acid and hydrochloric acid for pickling to neutralize the alkali residue and enhance the dehydration effect; S6: Water washing: Rinse the desorbed impurities and residual acid on the surface with deionized water; S7: Pre - dehydration: Pre - dehydrate the silicon wafer in a slow - lifting manner.

[0026] Optimizations have been made to the pre - cleaning and water - cleaning steps in the texturing process of existing Topcon cells. Through this process, the production requirements of Topcon cell texturing can be met, thus achieving mass production of high - resistivity silicon wafers for Topcon cells and improving the cell conversion efficiency.

[0027] Furthermore, in step S1, the bubbling pressure of the pre - cleaning is 0.2 - 0.5 Mpa, the bubbling flow rate of the pre - cleaning is 1 - 1.5 m³ / h, the temperature of the pre - cleaning is 70 ± 5 °C, and the cleaning time is 220 s.

[0028] Furthermore, in step S2, the cleaning temperature is room temperature and the cleaning time is 120 s.

[0029] Furthermore, in step S3, the post - cleaning temperature is 68 ± 5 °C and the cleaning time is 100 s.

[0030] Furthermore, in step S4, the cleaning temperature is room temperature and the cleaning time is 100 s.

[0031] Furthermore, in step S5, the cleaning temperature is room temperature and the cleaning time is 100 s.

[0032] Furthermore, in step S6, the cleaning temperature is room temperature and the cleaning time is 100 s.

[0033] Furthermore, in step S7, the post - cleaning temperature is 78 ± 5 °C, the cleaning time is 10 s, the lifting speed for slow lifting is 0 - 5 mm / s. After pre - dehydration, the silicon wafer is thoroughly dried in an oven at a high temperature. The oven drying temperature is 95 ± 5 °C and the time is 600 s.

[0034] Furthermore, temperature and white spot monitoring systems are set in steps S1 - S7. The temperature and white spot monitoring system includes a temperature sensor, a white spot detection SEM camera, a communication module, a central processor, a display, a temperature controller, and an alarm. The temperature sensor and the white spot detection SEM camera are both connected to the communication module, the communication module is connected to the central processor, and the central processor is connected to the display, the temperature controller, and the alarm.

[0035] Furthermore, the output ends of the temperature sensor and the white spot detection SEM camera are electrically connected to the input end of the communication module, the output end of the communication module is electrically connected to the input end of the central processor, and the output end of the central processor is electrically connected to the input ends of the display, the temperature controller, and the alarm.

[0036] Example: Solution 1: Adjust the bubbling pressure in tanks 1 - 3 from the original 0.2 Mpa to 0.4 Mpa. Adjust the flow rate from the original 1.5 m³ / h to 1 - 1.2 m³ / h. Currently, the white spots are smaller in area and less severe than before. As Figure 2 shown, fluff is shown under SEM, and the pyramid fluff surface has incomplete fluffing.

[0037] Solution 2: Adjust the pre - cleaning temperature before tank 1 / 2 from the original 65°C to 70°C, and adjust the post - cleaning temperature after tank 10 from the original 65°C to 68°C. Currently, the white spots after texturing are normal. As Figure 3 shown, the pyramid fluff surface shows normal fluffing under SEM.

[0038] Conclusion: Comparison before and after improvement: The white spots have been significantly improved, and after improvement, it can meet the on - site production requirements.

[0039] Working principle: Pre - cleaning: Adopt the method of deepening pre - cleaning to remove organic pollution on the silicon wafer surface and part of the mechanical damage layer; Water washing: Rinse the surface with deionized water to remove the desorbed impurities and residual alkali solution; Post - cleaning: Remove some organic substances in the additives remaining on the silicon wafer surface; Water washing: Rinse the surface with deionized water to remove the desorbed impurities and residual acid solution; Acid pickling: Use a mixture of hydrofluoric acid and hydrochloric acid for acid pickling to neutralize the alkali residues and increase the dehydration effect; Water washing: Rinse the surface with deionized water to remove the desorbed impurities and residual acid solution; Pre - dehydration: Use the slow - lift method to pre - dehydrate the silicon wafer; By increasing the overflow bubbling pressure and reducing the bubbling flow rate of the pre - cleaning tank process, the bubbling penetration is stronger, and the water cleaning temperature of the pre - cleaning tank is increased. Through the above measures, the activity of the liquid medicine is improved. By comprehensively adjusting the above - mentioned core processes, the pre - cleaning effect of the silicon wafer in the texturing process is improved, and the proportion of white spots decreases from 0.53% in the experiment to less than 0.02%. By adjusting the process parameters, a breakthrough in white spots during the texturing and blanking of Topcon batteries can be achieved, and the overall yield of Topcon battery wafers can be improved.

[0040] It should be noted that in this document, relational terms such as first and second (No. 1, No. 2), etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variation thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0041] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A method for solving the white spots in the texturing of TOPCon cells, characterized in that: It includes the following operation steps: S1: Pre - cleaning: Adopt the method of deep pre - cleaning to remove the organic pollution and part of the mechanical damage layer on the silicon wafer surface; S2: Water washing: Rinse the impurities and residual alkali solution that have been desorbed on the surface with deionized water; S3: Post - cleaning: Remove some organic substances in the additives remaining on the silicon wafer surface; S4: Water washing: Rinse the impurities and residual alkali solution that have been desorbed on the surface with deionized water; S5: Acid pickling: Carry out mixed acid pickling with hydrofluoric acid and hydrochloric acid to neutralize the alkali residue and enhance the dehydration effect; S6: Water washing: Rinse the impurities and residual acid solution that have been desorbed on the surface with deionized water; S7: Pre - dehydration: Use the slow lifting method to pre - dehydrate the silicon wafer.

2. A method for solving the white spots in the texturing of TOPCon cells according to claim 1, characterized in that: In the S1 step, the bubbling pressure of the pre - cleaning is 0.2 - 0.5 Mpa, the bubbling flow rate of the pre - cleaning is 1 - 1.5 m³ / h, the temperature of the pre - cleaning is 70 ± 5 °C, and the cleaning time is 220 s.

3. A method for solving the white spots in the texturing of TOPCon cells according to claim 1, wherein: In the S2 step, the cleaning temperature is room temperature and the cleaning time is 120 s.

4. A method for solving the white spots in the texturing of TOPCon cells according to claim 1, characterized in that: In the S3 step, the temperature of the post - cleaning is 68 ± 5 °C and the cleaning time is 100 s.

5. A method for solving the white spots in the texturing of TOPCon cells according to claim 1, characterized in that: In the S4 step, the cleaning temperature is room temperature and the cleaning time is 100 s.

6. A method for solving the white spots in the texturing of TOPCon cells according to claim 1, characterized in that: In the S5 step, the cleaning temperature is room temperature and the cleaning time is 100 s.

7. A method for solving the white spots in the texturing of TOPCon cells according to claim 1, characterized in that: In the S6 step, the cleaning temperature is room temperature and the cleaning time is 100 s.

8. A method for solving the white spots in the texturing of TOPCon cells according to claim 1, characterized in that: In the S7 step, the temperature of the post - cleaning is 78 ± 5 °C, the cleaning time is 10 s, the lifting speed used for slow lifting is 0 - 5 mm / s. After pre - dehydration, use an oven to thoroughly dry the silicon wafer at a high temperature. The oven drying temperature is 95 ± 5 °C and the time is 600 s.

9. A method for solving the white spots in the texturing of TOPCon cells according to claim 1, characterized in that: In the S1 - S7 steps, a temperature and white - spot monitoring system is set. The temperature and white - spot monitoring system includes a temperature sensor, a white - spot detection SEM camera, a communication module, a central processor, a display, a temperature controller and an alarm. The temperature sensor and the white - spot detection SEM camera are both connected to the communication module. The communication module is connected to the central processor. The central processor is connected to the display, the temperature controller and the alarm.

10. A method for solving the white spots in the texturing of TOPCon cells according to claim 9, characterized in that: The output ends of the temperature sensor and the white - spot detection SEM camera are electrically connected to the input end of the communication module. The output end of the communication module is electrically connected to the input end of the central processor. The output end of the central processor is electrically connected to the input ends of the display, the temperature controller and the alarm.

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