Auxiliary heating mechanism and diffusion furnace

Abstract

The utility model relates to the technical field of photovoltaic cell production, in particular to an auxiliary heating mechanism and a diffusion furnace, the auxiliary heating mechanism comprises a silicon carbide paddle and a plurality of heating pieces wound on the surface of the silicon carbide paddle, the surface of each heating piece is provided with a heat conduction coating, and the heat conduction coatings are arranged on the surface of the silicon carbide paddle. The heating piece comprises a heating wire and a heat dissipation structure wrapping the surface of the heating wire. According to the utility model, the wound heating wire is additionally arranged on the silicon carbide paddle in the furnace body shell to assist in heating, so that non-uniform temperature distribution caused by the fact that the silicon carbide paddle is made of opaque materials and hinders heat radiation is compensated, and non-uniform sheet resistance of a silicon wafer in an area shielded by the silicon carbide paddle structure is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaic cell production, and more particularly to an auxiliary heating mechanism and a diffusion furnace. Background Art

[0002] Currently, in order to increase the hourly output of a single machine in the photovoltaic industry, the wafer insertion method of the original high-temperature diffusion, boron diffusion or oxidation furnace has been changed from vertical to horizontal, and the single-tube wafer loading capacity has increased from 1,200 pieces to 2,400 pieces. In the actual production process, the silicon carbide paddle will always carry the quartz boat in the diffusion furnace to complete the entire diffusion process. Silicon carbide is an opaque material. The gas in the furnace and the silicon wafers are heated under the action of high-temperature radiation. Blocked by the structure of the silicon carbide paddle, for the silicon wafers in the blocked area, the temperature difference within the wafer is relatively large compared with other areas, such as the silicon wafers at the top or bottom, showing uneven temperature distribution characteristics. This characteristic will lead to differences in the diffusion depth of the doping source, that is, the unevenness of the PN junction, resulting in differences in the sheet resistance uniformity.

[0003] Therefore, it is necessary to provide an auxiliary heating mechanism and a diffusion furnace. Summary of the Utility Model

[0004] The utility model provides an auxiliary heating mechanism and a diffusion furnace to solve the above technical problems.

[0005] To achieve the above object, an embodiment of the utility model provides an auxiliary heating mechanism, including: a silicon carbide paddle and a plurality of heating elements wound on the surface of the silicon carbide paddle. A heat-conducting coating is provided on the surface of the heating element, and the heating element includes a heating wire and a heat-dissipating structure covering the surface of the heating wire.

[0006] Further, the heat-dissipating structure includes a plurality of heat-dissipating fins provided on the surface of the heating wire, and a heat flow channel is formed between two adjacent heat-dissipating fins.

[0007] The utility model also provides a diffusion furnace, including a furnace body housing and the above-mentioned auxiliary heating mechanism, and a part of the auxiliary heating mechanism is arranged inside the furnace body housing.

[0008] Further, a heating chamber is provided inside the furnace body housing.

[0009] Further, an intake pipe and an exhaust pipe are provided in the heating chamber.

[0010] Further, a quartz boat support is provided in the heating chamber. The quartz boat support is in a frame shape, and a plurality of card slots are provided at the tops of both sides of the quartz boat support.

[0011] Further, the diffusion furnace further includes a plurality of quartz boats, and clamping blocks matching the card slots are provided on both sides of the quartz boats.

[0012] Further, the quartz boat is arranged inside the quartz supporting boat, and both ends of the quartz boat extend outside the quartz supporting boat.

[0013] Further, a plurality of retaining bars adapted to hold the battery wafers are provided on the inner wall of the quartz boat.

[0014] Further, the diffusion furnace further includes a plurality of temperature sensors.

[0015] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0016] By adding a wound heating wire on the silicon carbide paddle inside the furnace body housing for auxiliary heating, compensating for the uneven temperature distribution caused by the silicon carbide paddle being an opaque material that hinders thermal radiation, and reducing the non-uniform sheet resistance of the silicon wafers in the area blocked by the structure of the silicon carbide paddle;

[0017] By dividing the heating wire into several segments and adjusting the number of heating wire segments for auxiliary heating according to the actual structure of the furnace body housing, uniform heating is improved;

[0018] By arranging temperature sensors near the silicon carbide paddle, the temperature of the auxiliary heating wire can be better adjusted;

[0019] By providing a heat-conducting coating on the heating element, metal contamination of the silicon wafers caused by the melting of the heating element at high temperatures is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present utility model will be further described below in conjunction with the drawings and embodiments.

[0021] Figure 1 It is a sectional view of the optimal embodiment of an auxiliary heating mechanism and a diffusion furnace in the prior art;

[0022] Figure 2 It is a partial structural schematic diagram of the silicon carbide paddle and the heating element of the present utility model;

[0023] Figure 3 It is a sectional view of the optimal embodiment of the heating element of the present utility model;

[0024] Figure 4 It is a perspective view of the optimal embodiment of the quartz supporting boat of the present utility model;

[0025] Figure 5 It is a perspective view of the optimal embodiment of the quartz boat of the present utility model.

[0026] Among them, 1. Furnace body shell; 2. Quartz carrier; 21. Card slot; 3. Quartz boat; 31. Card block; 32. Baffle; 4. Solar cell; 5. Inlet pipe; 6. Exhaust pipe; 7. Auxiliary heating mechanism; 71. Silicon carbide paddle; 72. Heating element; 73. Heat conduction coating; 74. Heating wire; 75. Heat dissipation fin; 76. Heat flow channel. Detailed implementation manners

[0027] Now, the present utility model will be further described in detail with reference to the accompanying drawings. These drawings are all simplified schematic diagrams, only showing the basic structure of the present utility model in a schematic manner, so they only show the components related to the present utility model.

[0028] Please refer to Figure 1 and combine with Figures 2 to 3 , Figure 1 which is a sectional view of the optimal embodiment of an auxiliary heating mechanism and a diffusion furnace in the prior art; Figure 2 which is a partial structural schematic diagram of the silicon carbide paddle and the heating element of the present utility model; Figure 3 which is a sectional view of the optimal embodiment of the heating element of the present utility model. As Figures 1 to 3 shown, at least one embodiment provides an auxiliary heating mechanism, including: a silicon carbide paddle 71 and a plurality of heating elements 72 wound on the surface of the silicon carbide paddle 71. A heat conduction coating 73 is provided on the surface of the heating element 72. Specifically, the heat conduction coating 73 is a non-metallic coating, including a boron nitride coating; by adding a wound heating wire 74 on the silicon carbide paddle 71 in the furnace body shell 1 for auxiliary heating, compensating for the uneven temperature distribution caused by the fact that the silicon carbide paddle 71 is an opaque material that hinders heat radiation, and reducing the non-uniform sheet resistance of the silicon wafers in the area blocked by the structure of the silicon carbide paddle 71; by dividing the heating wire 74 into several segments and adjusting the number of segments of the heating wire 74 for auxiliary heating according to the actual structure of the furnace body shell 1, the uniform heating is improved; by arranging a temperature sensor near the silicon carbide paddle 71, the temperature of the auxiliary heating wire is better adjusted; by providing a heat conduction coating 73 on the heating element 72, the metal pollution of the silicon wafers caused by the high-temperature melting of the heating element 72 is reduced; in order to enhance the heat equalization effect of the heating element 72, specifically, the heating element 72 includes a heating wire 74 and a heat dissipation structure coated on the surface of the heating wire 74. The heat dissipation structure includes a plurality of heat dissipation fins 75 provided on the surface of the heating wire 74, and a heat flow channel 76 between adjacent two heat dissipation fins 75. The heating structure and the heat dissipation structure cooperate with each other to enhance the heat flow uniformity and improve the effect of uniform heat flow. The heat dissipation fins 75 and the heating wire 74 are integrally formed of the same material, and the heat conduction coating 73 is provided on the surfaces of the heat dissipation fins 75 and the heating wire 74.

[0029] Please continue to refer to Figure 1 and combine with Figures 4 to 5 , Figure 4 which is a perspective view of the optimal embodiment of the quartz carrier of the present utility model;Figure 5 The perspective view of the optimal embodiment of the quartz boat of the present utility model is as Figure 1 , Figure 4 and Figure 5 shown. The present utility model also provides a diffusion furnace, which includes a furnace body housing 1 and the auxiliary heating mechanism 7 as described above. The auxiliary heating mechanism 7 is disposed in the furnace body housing 1. A heating chamber is provided inside the furnace body housing 1. An intake pipe 5 and an exhaust pipe 6 are provided in the heating chamber. A quartz boat support 2 is provided in the heating chamber. The quartz boat support 2 is in a frame shape, and a plurality of card slots 21 are provided at the tops of both sides of the quartz boat support 2. The diffusion furnace further includes a plurality of quartz boats 3. The quartz boat 3 is composed of four columns, a top piece and a bottom piece, and is used to carry the battery wafers 4. The quartz boat support 2 is used to carry the quartz boat 3 filled with battery wafers 4. Specifically, engaging blocks 31 matching the card slots 21 are provided on both sides of the quartz boat 3. The quartz boat 3 is disposed in the quartz boat support 2, and both ends of the quartz boat 3 extend outside the quartz boat support 2. A plurality of retaining bars 32 adapted to hold up the battery wafers 4 are provided on the inner wall of the quartz boat 3. The diffusion furnace further includes a plurality of temperature sensors (not shown in the figure), and the temperature sensors are provided on the inner wall of the furnace body housing 1 around the silicon carbide paddle 71.

[0030] In summary, by adding a wound heating wire 74 to the silicon carbide paddle 71 in the furnace body housing 1 for auxiliary heating, it compensates for the uneven temperature distribution caused by the silicon carbide paddle 71 being an opaque material that hinders heat radiation, and reduces the uneven sheet resistance of the silicon wafers in the area blocked by the structure of the silicon carbide paddle 71; by dividing the heating wire 74 into several segments and adjusting the number of segments of the auxiliary heating wire 74 according to the actual structure of the furnace body housing 1, the uniform heating is improved; by providing a temperature sensor near the silicon carbide paddle 71, the temperature of the auxiliary heating wire can be adjusted better; by providing a heat-conducting coating 73 on the heating element 72, the metal contamination of the silicon wafers caused by the melting of the heating element 72 at high temperature is reduced.

[0031] Based on the above inspiration from the ideal embodiment of the present utility model, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this utility model. The technical scope of this utility model is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An auxiliary heating mechanism, characterized in that: include: A silicon carbide paddle (71) and a plurality of heating elements (72) wound on the surface of the silicon carbide paddle (71), a thermal conductive coating (73) being arranged on the surface of the heating element (72), and the heating element (72) comprising a heating wire (74) and a heat dissipation structure coated on the surface of the heating wire (74).

2. An auxiliary heating mechanism according to claim 1, characterized in that: The heat dissipation structure comprises a plurality of heat dissipation fins (75) arranged on the surface of the heating wire (74), and a heat flow channel (76) between two adjacent heat dissipation fins (75).

3. A diffusion furnace, characterized in that: It comprises a furnace shell (1) and an auxiliary heating mechanism (7) as claimed in any one of claims 1 to 2, wherein a portion of the auxiliary heating mechanism (7) is arranged in the furnace shell (1).

4. A diffusion furnace as claimed in claim 3, characterized in that: A heating chamber is arranged inside the furnace shell (1).

5. A diffusion furnace as claimed in claim 4, characterized in that: An air inlet pipe (5) and an air exhaust pipe (6) are provided in the heating chamber.

6. A diffusion furnace as claimed in claim 4, characterized in that: A quartz boat (2) is arranged in the heating chamber. The quartz boat (2) is frame-shaped, and a plurality of slots (21) are arranged on the tops of both sides of the quartz boat (2).

7. A diffusion furnace according to claim 6, characterized in that: The diffusion furnace further comprises a plurality of quartz boats (3), and both sides of the quartz boats (3) are provided with clamping blocks (31) matching the clamping slots (21).

8. A diffusion furnace according to claim 7, characterized in that: The quartz boat (3) is arranged in the quartz support boat (2), and both ends of the quartz boat (3) extend outside the quartz support boat (2).

9. A diffusion furnace according to claim 8, characterized in that: The inner wall of the quartz boat (3) is provided with a plurality of blocking bars (32) suitable for supporting the battery sheet (4).

10. A diffusion furnace as claimed in claim 3, characterized in that: The diffusion furnace also includes a plurality of temperature sensors.

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