Diffusion furnace for solar cell production

Abstract

The utility model discloses a diffusion furnace for solar cell production, which comprises a furnace body and a furnace door, one side wall of the furnace body is fixedly connected with a first air inlet pipe and an exhaust pipe, the exhaust pipe penetrates through one side wall of the furnace body and goes deep into the furnace body, the first air inlet pipe is fixedly connected with a communicating piece, the communicating piece is provided with a plurality of interfaces, and the furnace door is fixedly connected with the furnace body. A second gas inlet pipe and a third gas inlet pipe are fixedly connected into a plurality of connectors in the communicating piece correspondingly, the second gas inlet pipe and the third gas inlet pipe penetrate through one side wall of the furnace body and extend into the furnace body, and a gas uniformizing spray head is rotationally connected to a pipe body, away from one end of the first gas inlet pipe, of the third gas inlet pipe; and the gas equalizing spray head is a hollow hemisphere. Compared with the prior art, the diffusion furnace for producing the solar cell can enable mixed gas in the middle of the diffusion furnace to flow, so that the quantity difference of deposition sources in the middle of the diffusion furnace is reduced, and the yield of the solar cell is effectively improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of diffusion furnaces for producing solar cell sheets, and in particular relates to a diffusion furnace for producing solar cell sheets. Background Art

[0002] Photovoltaic diffusion furnace equipment is one of the indispensable equipment in the manufacturing process of solar cells. Its main function is to dope the surface of silicon wafers to increase the electron concentration and conductivity of the silicon wafer surface, thereby improving the photoelectric conversion efficiency of solar cells.

[0003] The principle of photovoltaic diffusion furnace equipment is to spray mixed gas onto the surface of silicon wafer under high temperature and high pressure conditions, introduce doping elements into silicon crystals through diffusion, thereby changing the conductivity of silicon crystals. At the same time, an oxide film will be formed on the surface of silicon wafers to protect silicon crystals.

[0004] As the area of ​​solar cells increases, the volume of the diffusion furnace also increases. The existing diffusion furnace has an air inlet pipe at the upper end of the furnace tail responsible for conveying the mixed gas, and an exhaust pipe extends from the furnace tail to exhaust and discharge waste.

[0005] The mixed gas in the middle of the large-capacity diffusion furnace currently used is not easy to circulate, resulting in large differences in the amount of deposition source in the middle of the diffusion furnace, large fluctuations in the square resistance between each temperature zone, within the sheet, and between tubes, affecting uniformity. The poor uniformity of the square resistance of the solar cell affects the yield rate of the solar cell.

[0006] Therefore, in view of the above technical problems, it is necessary to provide a diffusion furnace for producing solar cells.

[0007] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to a person skilled in the art. Utility Model Content

[0008] The utility model aims to provide a diffusion furnace for producing solar cell sheets, which can solve the above problems.

[0009] In order to achieve the above-mentioned purpose, a specific embodiment of the utility model provides a diffusion furnace for the production of solar cell sheets, including a furnace body and a furnace door, a first air inlet pipe and an exhaust pipe are fixedly connected to one side wall of the furnace body, the exhaust pipe penetrates one side wall of the furnace body and extends into the furnace body, a second air inlet pipe and a third air inlet pipe are fixedly connected to the first air inlet pipe, the second air inlet pipe and the third air inlet pipe penetrate one side wall of the furnace body and extend into the interior of the furnace body, a gas equalizing nozzle is rotatably connected to the tube body of the third air inlet pipe away from one end of the first air inlet pipe, the second air inlet pipe and the third air inlet pipe realize dual-path air intake, and can even out the concentration of the mixed gas in the furnace body.

[0010] In one or more embodiments of the present utility model, a connecting piece is fixedly connected to the first air intake pipe, and the connecting piece has a plurality of interfaces, and the number of the interfaces is at least three.

[0011] In one or more embodiments of the present invention, a second air inlet pipe and a third air inlet pipe are sealed and connected to the interface of the connecting piece, and the first air inlet pipe is divided into two air inlet paths through the connecting piece. The total amount of mixed gas transported into the furnace body can be controlled by controlling the first air inlet pipe.

[0012] In one or more embodiments of the present invention, a regulating valve is fixedly installed on the tube body of the third air inlet pipe close to the connecting piece. The regulating valve is between the outer wall of the furnace body and the connecting piece. By adjusting the opening size of the regulating valve, the amount of mixed gas delivered into the furnace body from the third air inlet pipe can be adjusted.

[0013] In one or more embodiments of the present invention, the length of the third air inlet pipe extending into the furnace body is 2.8m-3.2m, so that the air outlet of the third air inlet pipe can be located in the middle of the furnace body.

[0014] In one or more embodiments of the present invention, a slewing bearing is fixedly installed on the tube body of the third air inlet pipe, and the inner ring diameter of the slewing bearing matches the inner diameter of the third air inlet pipe. The slewing bearing is fixedly connected to the tube body of the third air inlet pipe, so that the third air inlet pipe can enter the furnace body without affecting the sealing.

[0015] In one or more embodiments of the utility model, an air equalizing nozzle is fixedly connected to the outer ring of the slewing bearing, and the air equalizing nozzle is a hollow hemisphere. The air equalizing nozzle can rotate on the tube body of the third intake pipe through the fixedly connected slewing bearing. The outer wall of the air equalizing nozzle is provided with a first jet port, a second jet port and a third jet port, and the air equalizing nozzle can rotate through the slewing bearing.

[0016] In one or more embodiments of the utility model, the first jet port and the second jet port on the gas equalizing nozzle are on the same cross-section, the diameter of the first jet port is smaller than the diameter of the second jet port, the first jet port and the second jet port are symmetrically distributed on the gas equalizing nozzle, and the third jet port is opened on the side of the gas equalizing nozzle away from the slewing bearing. The first jet port, the second jet port and the third jet port on the gas equalizing nozzle spray out mixed gas, so that the concentration of the mixed gas in the furnace body is uniform.

[0017] Compared with the prior art, the utility model of a diffusion furnace for producing solar cells can make the mixed gas in the middle of the diffusion furnace flow, thereby reducing the difference in the amount of deposition sources in the middle of the diffusion furnace and effectively improving the yield rate of solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art description. Obviously, the drawings described below are only some embodiments recorded in the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a schematic diagram of the structure of a diffusion furnace for producing solar cells in one embodiment of the utility model;

[0020] Figure 2 A cross-sectional view of a diffusion furnace for producing solar cells in one embodiment of the utility model;

[0021] Figure 3 This is a schematic diagram of a dual-path air intake air pipe structure of a diffusion furnace for producing solar cell sheets in one embodiment of the utility model;

[0022] Figure 4 It is a structural schematic diagram of a uniform gas nozzle of a diffusion furnace for producing solar cells in one embodiment of the utility model;

[0023] Description of main reference numerals:

[0024] 1. Furnace body; 11. Furnace door; 2. First air inlet pipe; 21. Connecting piece; 22. Second air inlet pipe; 23. Third air inlet pipe; 231. Regulating valve; 3. Rotary bearing; 4. Air uniformity nozzle; 41. First air jet; 42. Second air jet; 43. Third air jet; 5. Exhaust pipe; 6. Pressure gauge; 7. Thermocouple. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0026] like Figure 1 As shown, a diffusion furnace for producing solar cells in one embodiment of the utility model comprises a furnace body 1, a furnace door 11 is hinged at the furnace mouth of the furnace body 1, and the furnace door 11 can be rotated to open or close the furnace body 1, and the solar cells can be placed in the furnace body 1 from the open position of the furnace door 11. A second air inlet pipe 22, a third air inlet pipe 23 and an exhaust pipe 5 are penetrated through the rear side wall of the furnace body 1, and the second air inlet pipe 22 and the third air inlet pipe 23 convey mixed gas, and the used waste gas is extracted from the interior of the furnace body 1 by the exhaust pipe 5.

[0027] like Figures 1 to 3 As shown, in order to ensure the accurate amount of mixed gas entering the furnace body 1, a connecting piece 21 is welded at the pipe openings of the second air inlet pipe 22 and the third air inlet pipe 23 away from the furnace body 1. The connecting piece 21 has three openings, two of which are connected to the second air inlet pipe 22 and the third air inlet pipe 23 respectively, and the other opening is connected to a straight pipe section, and the first air inlet pipe 2 is welded to the straight pipe section. In this way, the mixed gas in the second air inlet pipe 22 and the third air inlet pipe 23 is supplied by the first air inlet pipe 2, and the amount of mixed gas entering the furnace body 1 can be controlled by controlling the mixed gas entering from the first air inlet pipe 2.

[0028] Preferably, the connecting piece 21 is a connecting piece made of polytetrafluoroethylene, which has the characteristics of corrosion resistance and high temperature resistance and can meet the requirements of the scheme.

[0029] The second air inlet pipe 22 penetrates into the furnace body 1 from the rear of the furnace body 1, and the opening of the second air inlet pipe 22 is located at the rear of the furnace body 1. When the mixed gas in the second air inlet pipe 22 flows out from the opening of the second air inlet pipe 22, the mixed gas can diffuse from the rear of the furnace body 1 to the furnace mouth of the furnace body 1. The third air inlet pipe 23 also penetrates into the furnace body 1 from the rear of the furnace body 1, and the opening of the third air inlet pipe 23 is set in the middle of the furnace body 1.

[0030] Preferably, the length of the third air inlet pipe 23 penetrating into the furnace body 1 is 2.8 m-3.2 m.

[0031] Specifically, the mixed gas flowing out from the opening of the second air inlet pipe 22 diffuses from the rear of the furnace body 1 toward the furnace mouth of the furnace body 1, and is finally extracted from the interior of the furnace body 1 by the exhaust pipe 5. Due to the large volume of the furnace body 1, the mixed gas gathers in the middle of the furnace body 1, and the mixed gas blown out from the outlet of the third air inlet pipe 23 can disturb the mixed gas gathered in the middle of the furnace body 1, thereby accelerating the flow rate of the mixed gas. In this way, the deposition source amount of the mixed gas in the middle of the furnace body 1 can be reduced, and the uniformity of the internal square resistance of the solar cell can be improved.

[0032] like Figure 3 and Figure 4 As shown, in order to make the mixed gas contacted by the solar cells in the middle and rear of the furnace body 1 more uniform, a regulating valve 231 is fixedly installed on the wall of the third air inlet pipe 23, and the regulating valve 231 is installed on the outer side of the rear side wall of the furnace body 1. The regulating valve 231 can adjust the amount of mixed gas entering the furnace body 1.

[0033] Specifically, the second air inlet pipe 22 and the third air inlet pipe 23 share a first air inlet pipe 2 to supply the mixed gas. When the regulating valve 231 is closed, the mixed gas is all supplied into the interior of the furnace body 1 by the second air inlet pipe 22. When the first air inlet pipe 2 is fully opened, the amount of mixed gas supplied to the second air inlet pipe 22 and the third air inlet pipe 23 is the same.

[0034] Furthermore, after placing the solar cell in the furnace body 1 and closing the furnace door 11, 321 is first closed, and the mixed gas is supplied into the furnace body 1 through the second air inlet pipe 22, and the exhaust pipe 5 exhausts air outward. When the gas volume reaches half of the volume of the furnace body 1, 321 is opened, and the mixed gas is supplied into the furnace body 1 through the second air inlet pipe 22 and the third air inlet pipe 23. In this way, the efficiency of supplying the mixed gas is higher, and the mixed gas can quickly fill the internal space of the furnace body 1, which can improve production efficiency.

[0035] A slewing bearing 3 is welded on the pipe wall at the outlet position of the third air inlet pipe 23, and the inner rotating ring of the slewing bearing 3 is welded on the inner wall of the pipe body of the third air inlet pipe 23. An air equalizing nozzle 4 is welded on the outer ring of the slewing bearing 3, and the air equalizing nozzle 4 is a hollow semicircular sphere, and the air equalizing nozzle 4 can be rotatably connected to the third air inlet pipe 23 through the slewing bearing 3.

[0036] It is worth noting that the slewing bearing 3 is made of high temperature resistant material and can withstand the high temperature in the diffusion furnace. The size of the slewing bearing 3 and the gas equalizing nozzle 4 matches the outer diameter of the third air inlet pipe 23 so that the third air inlet pipe can smoothly enter the furnace body 1.

[0037] The spherical wall of the uniform air nozzle 4 is provided with a first jet port 41, a second jet port 42 and a third jet port 43, wherein the third jet port 43 is provided at the front side of the spherical body of the uniform air nozzle 4. The first jet port 41 and the second jet port 42 are provided on the outer wall of the vertical maximum diameter of the uniform air nozzle 4, and the positions of the first jet port 41 and the second jet port 42 are symmetrical. The diameters of the first jet port 41 and the second jet port 42 are different, and the diameter of the first jet port 41 is smaller than the diameter of the second jet port 42.

[0038] Specifically, when the mixed gas supplied in the third air inlet pipe 23 is blown into the interior of the gas equalizing nozzle 4, the mixed gas is blown out from the first jet port 41 and the second jet port 42. Because the diameter of the first jet port 41 is smaller than the diameter of the second jet port 42, the flow velocity and flow rate of the mixed gas blown out from the first jet port 41 and the second jet port 42 are different, so the gas equalizing nozzle 4 can be pushed to rotate slowly through the slewing bearing 3.

[0039] Specifically, since the diameters of the first jet port 41, the second jet port 42 and the third jet port 43 are much smaller than the outlet diameter of the third air inlet pipe 23, the flow rate of the mixed gas ejected from the first jet port 41, the second jet port 42 and the third jet port 43 will be accelerated. In this way, the flow of the gas in the middle of the furnace body 1 can be made. At the same time, when the uniform gas nozzle 4 rotates, the gas ejected from the third jet port 43 is spirally ejected into the furnace body 1, so that the mixed gas on the solar cell in the furnace body 1 is diffused more evenly.

[0040] Furthermore, the opening amount of the regulating valve 231 can be adjusted to control the amount of mixed gas entering the third air inlet pipe 23, thereby controlling the rotation speed of the uniform air nozzle 4. It is worth noting that the rotation speed of the uniform air nozzle 4 should not be too fast, and slow rotation is more conducive to the diffusion process.

[0041] When in use, the furnace door 11 is opened, the solar cell is placed in the furnace body 1, and then the furnace door 11 is closed to seal the furnace body 1, and the mixed gas is transported into the furnace body 1, while the exhaust pipe 5 exhausts gas outward. The mixed gas is transported to the furnace tail and the furnace middle of the furnace body 1 from the second air inlet pipe 22 and the third air inlet pipe 23, respectively. When the mixed gas flows into the uniform gas nozzle 4 from the third air inlet pipe 23, the uniform gas nozzle 4 rotates, and the mixed gas ejected from the first air jet 41, the second air jet 42 and the third air jet 43 can evenly distribute the mixed gas concentration in the furnace body 1.

[0042] When the mixed gas is transported into the furnace body 1, the concentration of the mixed gas in the furnace body 1 can be determined by observing the pressure gauge 6 and the thermocouple 7. When the amount of mixed gas transported from the first air inlet pipe 2 reaches a predetermined value, the opening of the regulating valve 231 is reduced, and the flow rate of the mixed gas in the third air inlet pipe 23 slows down, causing the gas homogenizing nozzle 4 to rotate slowly. In this way, the mixed gas ejected from the first jet port 41, the second jet port 42 and the third jet port 43 disturbs the mixed gas in the middle of the furnace body 1 without affecting the diffusion process of the diffusion furnace. When the diffusion process is completed, the furnace door 11 is opened, and the solar cell can be taken out, and the diffusion work is completed.

[0043] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0044] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A diffusion furnace for producing solar cell sheets, comprising a furnace body and a furnace door, wherein a first air inlet pipe and an air exhaust pipe are fixedly connected to one side wall of the furnace body, and the air exhaust pipe penetrates through one side wall of the furnace body and penetrates into the furnace body, characterized in that: The first air inlet pipe is fixedly connected to a second air inlet pipe and a third air inlet pipe, the second air inlet pipe and the third air inlet pipe penetrate a side wall of the furnace body and extend into the interior of the furnace body, and the third air inlet pipe is rotatably connected to an air equalizing nozzle on the tube body away from one end of the first air inlet pipe.

2. The diffusion furnace for producing solar cells according to claim 1, characterized in that: A connecting piece is fixedly connected to the first air inlet pipe, and the connecting piece has a plurality of interfaces, and the number of the interfaces is at least three.

3. The diffusion furnace for producing solar cells according to claim 2, characterized in that: The second air inlet pipe and the third air inlet pipe are sealed and connected to the interface of the connecting piece.

4. The diffusion furnace for producing solar cells according to claim 3, characterized in that: A regulating valve is fixedly mounted on the tube body of the third air inlet pipe close to the connecting piece, and the regulating valve is between the outer wall of the furnace body and the connecting piece.

5. The diffusion furnace for producing solar cells according to claim 3, characterized in that: The length of the third air inlet pipe extending into the furnace body is 2.8m-3.2m.

6. The diffusion furnace for producing solar cells according to claim 3, characterized in that: A slewing bearing is fixedly mounted on the pipe body of the third air inlet pipe.

7. The diffusion furnace for producing solar cells according to claim 6, characterized in that: The inner ring diameter of the slewing bearing matches the inner diameter of the third air intake pipe, and the slewing bearing is fixedly connected to the pipe body of the third air intake pipe.

8. The diffusion furnace for producing solar cells according to claim 7, characterized in that: An air equalizing nozzle is fixedly connected to the outer ring of the slewing bearing. The air equalizing nozzle is a hollow hemisphere. The air equalizing nozzle can rotate on the pipe body of the third air intake pipe through the fixedly connected slewing bearing.

9. The diffusion furnace for producing solar cells according to claim 8, characterized in that: The outer wall of the gas uniformity nozzle is provided with a first gas injection port, a second gas injection port and a third gas injection port.

10. The diffusion furnace for producing solar cells according to claim 9, characterized in that: The first jet port and the second jet port on the gas equalizing nozzle are on the same cross section, the diameter of the first jet port is smaller than the diameter of the second jet port, the first jet port and the second jet port are symmetrically distributed on the gas equalizing nozzle, and the third jet port is opened on the side of the gas equalizing nozzle away from the slewing bearing.

Images