Solar cell sintering furnace and solar cell sintering method

Abstract

The present application relates to the field of photovoltaic manufacturing, and particularly relates to a solar cell sintering furnace and a solar cell sintering method, which comprises a sintering furnace cavity, a furnace belt and a heating unit; the furnace belt penetrates through the sintering furnace cavity along the length direction of the sintering furnace cavity, and is used for transporting the solar cell precursors to be processed; the heating unit is arranged in the sintering furnace cavity and surrounds the furnace belt; the heating temperature of the heating unit to the furnace belt gradually decreases from the edge area of the furnace belt to the middle area of the furnace belt. Since the temperature of the edge position of the solar cell precursor is higher than that of the center position of the solar cell precursor, the metallization depth at the edge is different from that at the center position in the sintering process, can better cooperate with each epitaxial layer in the previous diffusion node step, improves the connection effect of the metal electrode, and improves the battery yield.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic manufacturing, in particular to a solar cell sintering furnace and a sintering method of a solar cell. BACKGROUND

[0002] TOPCon cell refers to preparing a 1-2nm ultra-thin tunneling oxide layer (SiO x ) on the back of a silicon wafer, then depositing a doped polysilicon layer with a thickness of 60-160nm on the surface of the SiO x , and finally depositing silicon nitride on the doped polysilicon layer. The structure provides good surface passivation and field passivation for the back of the silicon wafer. The ultra-thin oxide layer can make electrons tunnel into the polysilicon layer while blocking the transport of holes, reducing the recombination current. The lateral transport characteristics of the doped polysilicon layer reduce the series resistance. The above two characteristics together improve the open-circuit voltage, fill factor and conversion efficiency of the cell, and are the most likely next-generation high-efficiency cell technology to achieve large-scale production.

[0003] Due to the heating mode of the existing tubular high-temperature equipment, the radiant heat of the edge of the cell wafer is strong, and the radiant heat of the middle of the cell wafer is weak. This leads to uneven thermal field in the cell wafer, which further affects the front boron diffusion junction depth and surface concentration, the thickness of the silicon dioxide tunneling layer, and the in-wafer uniformity of the doped polysilicon process. For example, in the boron diffusion process, due to uneven heating of the silicon wafer, the diffusion junction depth of the edge of the cell wafer is deeper than the middle, and the surface concentration of the edge of the cell wafer is lower than the middle, so the edge sheet resistance is lower and the middle is higher; the in-wafer uniformity of the ultra-thin tunneling oxide layer (SiO x ) shows a point where the middle is thin and the edge is thick; the doped polysilicon layer shows a point where the middle sheet resistance is high and the edge sheet resistance is low.

[0004] Due to the above process differences between the edge and the middle of the cell wafer, and the existing sintering furnace heating mode which is low in temperature at the edge of the cell wafer and high in temperature in the middle, the sintering result does not match the level characteristics formed in the previous step due to the low temperature in the middle and the high temperature at the edge, leading to EL defects such as cell black edge and regional darkening, reducing the cell yield and increasing the production cost.

[0005] Therefore, how to reduce the EL defects such as cell black edge and regional darkening of the solar cell and improve the cell yield is a problem to be solved in the prior art. SUMMARY

[0006] The purpose of the present application is to provide a solar cell sintering furnace and a sintering method of a solar cell to solve the problem of reducing the EL defects such as cell black edge and regional darkening of the solar cell and improving the cell yield in the prior art.

[0007] To solve the above technical problems, the present application provides a solar cell sintering furnace, which comprises a sintering furnace cavity, a furnace belt and a heating unit.

[0008] The furnace belt runs through the sintering furnace cavity along the length direction of the sintering furnace cavity for transporting the solar cell precursors to be processed.

[0009] The heating unit is arranged in the sintering furnace cavity and surrounds the furnace belt.

[0010] The heating temperature of the heating unit gradually decreases from the edge area of the furnace belt to the middle area of the furnace belt.

[0011] Optionally, in the solar cell sintering furnace, the heating unit is a heating lamp tube.

[0012] Optionally, in the solar cell sintering furnace, the heating lamp tube is a straight lamp tube with the extending direction parallel to the length direction of the sintering furnace cavity.

[0013] Optionally, in the solar cell sintering furnace, the plane where the annular lamp tube is located is perpendicular to the length direction of the sintering furnace cavity.

[0014] Optionally, in the solar cell sintering furnace, the sintering furnace cavity is an annular cavity.

[0015] The laying density of the heating unit decreases with the increase of the included angle between the laying position and the plane where the solar cell precursors are located.

[0016] Optionally, in the solar cell sintering furnace, it further comprises a heat exchange device; the heat exchange device comprises a hot exhaust gas inlet, a heat exchange chamber and a waste exhaust gas outlet.

[0017] The hot waste gas of the sintering furnace cavity enters the heat exchange chamber through the hot exhaust gas inlet and is discharged through the waste exhaust gas outlet.

[0018] The fresh air pipeline of the solar cell sintering furnace passes through the heat exchange chamber, so that the fresh air in the external environment exchanges heat with the hot waste gas.

[0019] Optionally, in the solar cell sintering furnace, the heat exchange device is located above the sintering furnace cavity.

[0020] Correspondingly, the hot exhaust gas inlet is located at the top of the sintering furnace cavity.

[0021] Optionally, in the solar cell sintering furnace, the heat exchange device is a tubular heat exchange device.

[0022] The tubular heat exchange device is arranged in parallel with the sintering furnace cavity.

[0023] The pipe heat exchange device comprises a plurality of hot exhaust air inlets, which are arranged at intervals along the length direction of the sintering furnace cavity.

[0024] Optionally, in the solar cell sintering furnace, the heating unit is arranged only in the upper half or lower half of the sintering furnace cavity and is opposite to the back surface of the solar cell precursor.

[0025] Optionally, in the solar cell sintering furnace, the fresh air inlet and the fresh air outlet of the fresh air pipeline of the solar cell sintering furnace are arranged at the precursor inlet of the sintering furnace cavity.

[0026] Optionally, in the solar cell sintering furnace, the fresh air inlet is located outside the sintering furnace cavity and is not more than 30 cm away from the precursor inlet.

[0027] The fresh air outlet is located inside the sintering furnace cavity and is not more than 30 cm away from the precursor inlet.

[0028] A sintering method of a solar cell, which is a sintering method of a solar cell using the solar cell sintering furnace as described above.

[0029] The solar cell sintering furnace provided by the application comprises a sintering furnace cavity, a furnace belt and a heating unit; the furnace belt penetrates through the sintering furnace cavity along the length direction of the sintering furnace cavity and is used for transporting a solar cell precursor to be processed; the heating unit is arranged in the sintering furnace cavity and surrounds the furnace belt; and the heating temperature of the heating unit to the furnace belt gradually decreases from the edge region of the furnace belt to the middle region of the furnace belt.

[0030] The heating unit is arranged in the sintering furnace cavity and surrounds the solar cell precursor to perform heat radiation from various directions; by adjusting the heating temperature of the heating unit to different positions of the furnace belt, the temperature of the edge position of the solar cell precursor is higher than that of the central position of the solar cell precursor, so that the metallization depth of the edge position is different from that of the central position in the sintering process, and the edge position can better cooperate with the boron diffusion junction, the tunnel layer and the doped polysilicon layer of different depths and thicknesses in the previous diffusion junction step, thereby improving the connection effect of the metal electrode, greatly reducing the EL defects such as black edges and area darkening of the solar cell, and improving the yield of the solar cell. The application also provides a sintering method of a solar cell with the above beneficial effects. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to make the technical scheme of the present application or prior art clearer, the accompanying drawings needed in the description of the embodiments or prior art will be briefly introduced. Obviously, the accompanying drawings in the description are only some embodiments of the present application, and all other embodiments obtained by those of ordinary skill in the art without creative effort based on the accompanying drawings are within the protection scope of the present application.

[0032] Figure 1 A structural schematic diagram of one specific embodiment of the solar cell sintering furnace provided by the present application;

[0033] Figure 2 A structural schematic diagram of another specific embodiment of the solar cell sintering furnace provided by the present application;

[0034] Figure 3 A structural schematic diagram of still another specific embodiment of the solar cell sintering furnace provided by the present application;

[0035] Figure 4 A conveying schematic diagram of the solar cell precursor of one specific embodiment of the solar cell sintering furnace provided by the present application. EMBODIMENT

[0036] In order to make the technical scheme of the present application or prior art clearer, the accompanying drawings needed in the description of the embodiments or prior art will be briefly introduced. Obviously, the accompanying drawings in the description are only some embodiments of the present application, and all other embodiments obtained by those of ordinary skill in the art without creative effort based on the accompanying drawings are within the protection scope of the present application.

[0037] The core of the present application is to provide a solar cell sintering furnace, a structural schematic diagram of one specific embodiment of which is shown in Figure 1 , which is referred to as specific embodiment one, and includes a sintering furnace cavity 20, a furnace belt 50 and a heating unit 10.

[0038] The furnace belt 50 penetrates the sintering furnace cavity 20 along the length direction of the sintering furnace cavity 20, and is used for transporting the solar cell precursor to be processed.

[0039] The heating unit 10 is arranged in the sintering furnace cavity 20, and surrounds the furnace belt 50.

[0040] The heating temperature of the heating unit 10 to the furnace belt 50 gradually decreases from the edge area of the furnace belt 50 to the middle area of the furnace belt 50.

[0041] As a specific embodiment, the heating unit 10 is a heating lamp tube. The heating lamp tube is low in cost, high in installation freedom, and good in versatility. Of course, the heating unit 10 can also be selected according to actual conditions, such as an infrared lamp tube, a full-wave band lamp tube, a heating wire, etc.

[0042] Further, the heating lamp tube is a straight lamp tube with an extension direction parallel to the length direction of the sintering furnace cavity 20. The straight lamp tube is low in processing difficulty and low in installation cost. Of course, the heating lamp tube can also be arranged in other directions, such as an extension direction perpendicular to the length direction of the sintering furnace cavity 20. Figure 1 The heating unit 10 in FIG. 1 is a cross section of the straight lamp tube, and at the same time, Figure 1 The cross-sectional view in FIG. 1 shows that the sintering furnace cavity 20 is discontinuous. The upper and lower areas of the cross section can be regarded as a through hole, and it does not mean that the sintering furnace cavity 20 must be composed of two discontinuous arc shapes.

[0043] The sintering furnace heating cavity can be designed as a ring-shaped cavity. The arrangement form of the heating unit 10 in the ring-shaped cavity can be along the moving direction of the solar cell precursor or perpendicular to the moving direction of the solar cell precursor.

[0044] The sintering furnace heating cavity is designed with four temperature zones, which are a drying zone, a temperature rising zone, a sintering zone, and a temperature falling zone. According to the different temperatures, the arrangement density of the heating unit 10 in the ring-shaped cavity is also different.

[0045] The lamp tube arrangement in the drying zone, the temperature rising zone, and the temperature falling zone is similar to that in the sintering zone. However, the required temperature range of the drying zone, the temperature rising zone, and the temperature falling zone is lower than that of the sintering zone. Therefore, the arrangement density of the lamp tube (i.e., the heating unit 10) can be decreased in turn.

[0046] As shown in FIG. 2, Figure 1 The sintering furnace cavity 20 is a ring-shaped cavity. Due to the different distances from the furnace belt 50, the improved sintering furnace heat zone temperature distribution can meet the requirement that the middle area of the solar cell precursor needs a lower temperature than the edge area during sintering, and at the same time, a larger direct radiation heat is given to the edge area of the solar cell precursor, which meets the requirement that the sintering temperature of the middle area of the solar cell precursor is low and the sintering temperature of the edge area is high.

[0047] After the screen printing of the solar cell precursor is completed, the solar cell precursor is transported into the sintering furnace by a metal chain or a ceramic roller. The arrangement of the heating lamp tubes in the drying zone, the temperature rising zone, the sintering zone, and the temperature falling zone is consistent. According to the different required temperatures in each area, the arrangement density of the lamp tubes is different. The temperature of the drying zone of the sintering furnace is between 200°C and 400°C. The temperature of the temperature rising zone is between 400°C and 700°C. The temperature of the sintering zone is between 700°C and 870°C. The temperature of the temperature falling zone is between 700°C and 300°C.

[0048] As another specific embodiment, the plane of the ring-shaped lamp tube is perpendicular to the length direction of the sintering furnace cavity 20. The ring-shaped lamp tube can ensure that the heat energy diffused in all directions is basically consistent, so that only the length-to-short-axis ratio of the sintering furnace cavity 20 needs to be adjusted to obtain a suitable heating effect suitable for the different edge and center positions of the solar cell precursor.

[0049] In addition, the solar cell sintering furnace further comprises a heat exchange device; the heat exchange device comprises a hot exhaust gas inlet 31, a heat exchange chamber 32, and a waste exhaust gas outlet 33.

[0050] The hot exhaust gas of the sintering furnace cavity 20 enters the heat exchange chamber 32 through the hot exhaust gas inlet 31 and is discharged through the waste exhaust gas outlet 33.

[0051] The fresh air pipeline of the solar cell sintering furnace passes through the heat exchange chamber 32, so that the fresh air in the external environment exchanges heat with the hot exhaust gas.

[0052] The specific embodiment can refer to Figure 2 After the heat exchange device is added, the fresh air conveyed in the fresh air pipeline of the solar cell sintering furnace can exchange heat with the high-temperature exhaust gas discharged from the sintering furnace cavity 20 in the heat exchange chamber 32, so that the external fresh air has a certain degree of high temperature when entering the sintering furnace cavity 20, thereby improving the temperature uniformity of each region in the furnace. In this way, the fresh air entering the sintering furnace is preheated, the disturbance of the cold air directly entering the sintering furnace to the thermal field distribution in the sintering furnace is reduced, the influence of temperature fluctuation on the stability of the sintering process of the silicon wafer is reduced, the waste heat is fully utilized, the waste of electric energy is reduced, and the production cost is reduced.

[0053] Further, the heat exchange device is located above the sintering furnace cavity 20.

[0054] Correspondingly, the hot exhaust gas inlet 31 is located at the top of the sintering furnace cavity 20.

[0055] Of course, the hot exhaust gas of the sintering furnace cavity 20 will rise by itself, so that the heat exchange device is arranged above the sintering furnace cavity 20, which is beneficial to the smooth discharge of the hot exhaust gas from the hot exhaust gas inlet 31 at the top, so that the air circulation is more smooth. Further, the waste exhaust gas outlet 33 is arranged at the top of the heat exchange chamber 32, which is convenient for the discharge of the hot exhaust gas.

[0056] Of course, even if the heat exchange device is not installed, the hot exhaust gas in the sintering furnace cavity 20 still needs to be discharged through the exhaust port, and preferably, the exhaust port is also arranged at the top of the sintering furnace cavity 20.

[0057] Further, the heat exchange device is a tubular heat exchange device.

[0058] The tubular heat exchange device is arranged in parallel with the sintering furnace cavity 20.

[0059] The tubular heat exchange device comprises a plurality of hot exhaust inlets 31, which are arranged along the length direction of the sintering furnace cavity 20.

[0060] The tubular heat exchange device is arranged in the same direction as the sintering furnace cavity 20, which is convenient for installation and space planning. In addition, the plurality of hot exhaust inlets arranged along the length direction of the sintering furnace cavity 20 can make the hot exhaust gas more evenly distributed in the heat exchange chamber 32, improve the heat exchange effect, and improve the initial temperature of the fresh air entering the sintering furnace cavity 20, thereby further improving the thermal field. Of course, the fresh air pipeline advances in the heat exchange chamber 32 in a zigzag manner.

[0061] The sintering furnace for solar cells comprises a sintering furnace cavity 20, a furnace belt 50, and a heating unit 10. The furnace belt 50 penetrates the sintering furnace cavity 20 along the length direction of the sintering furnace cavity 20, and is used for transporting solar cell precursors to be processed. The heating unit 10 is arranged in the sintering furnace cavity 20 and surrounds the furnace belt 50. The heating temperature of the heating unit 10 to the furnace belt 50 gradually decreases from the edge region of the furnace belt 50 to the middle region of the furnace belt 50. The heating unit 10 is arranged in the sintering furnace cavity 20 and surrounds the furnace belt 50, and performs heat radiation on the solar cell precursors from all directions. By adjusting the heating temperature of the heating unit 10 to different positions of the furnace belt 50, the temperature of the edge position of the solar cell precursors is higher than that of the center position of the solar cell precursors. Therefore, in the sintering process, the metallization depth of the edge position is different from that of the center position, which can better cooperate with the boron diffusion junction, the tunnel layer, and the doped polysilicon layer of different depths and thicknesses in the previous diffusion junction step, improve the connection effect of the metal electrode, greatly reduce the EL defects such as black edges and area darkening of the solar cell, and improve the yield of the solar cell.

[0062] On the basis of the first embodiment, the density distribution of the heating unit 10 is further limited to obtain the second embodiment, as shown in the structural schematic view. Figure 3 The sintering furnace for solar cells comprises a sintering furnace cavity 20, a furnace belt 50, and a heating unit 10.

[0063] The furnace belt 50 penetrates the sintering furnace cavity 20 along the length direction of the sintering furnace cavity 20, and is used for transporting solar cell precursors to be processed.

[0064] The heating unit 10 is arranged in the sintering furnace cavity 20 and surrounds the furnace belt 50.

[0065] The heating temperature of the heating unit 10 to the furnace belt 50 gradually decreases from the edge region of the furnace belt 50 to the middle region of the furnace belt 50.

[0066] The sintering furnace cavity 20 is a ring-shaped cavity.

[0067] The laying density of the heating unit 10 decreases with the increase of the angle between the laying position and the plane where the solar cell precursor is located.

[0068] The embodiment is different from the above embodiment in that the density of the heating unit 10 varies with the angle of the heating unit 10 on the inner wall, and the rest of the structure is the same as the above embodiment, which will not be described here.

[0069] The embodiment emphasizes that the heating effect of the solar cell precursor in different regions is different due to the distance from the heating unit 10 on the inner wall, and the center region has a lower temperature and the edge region has a higher temperature. Therefore, the shape of the sintering furnace cavity 20 (the ring-shaped cavity can be a regular circular ring or an elliptical ring) is further limited to change the distribution of the heating unit 10 on the inner wall of the sintering furnace cavity 20 in different positions, and the characteristics of the center heating effect being worse than the edge heating effect are emphasized. Figure 3 The sintering furnace cavity 20 is a ring-shaped cavity.

[0070] Specifically, in the embodiment, the plane where the solar cell precursor is located is a horizontal plane, and as the angle between the line connecting the inner wall position where the heating unit 10 is arranged and the center of the sintering furnace cavity 20 and the horizontal plane increases, the density of the heating unit 10 becomes lower and lower (it can also be considered that the farther away from the horizontal plane, the lower the density of the heating unit 10), which realizes the characteristics of the center position of the solar cell precursor having a poor heating effect and the edge having a strong heating effect.

[0071] As a specific embodiment, the heating unit 10 is only arranged in the upper half or lower half of the sintering furnace cavity 20 and opposite to the back of the solar cell precursor. At present, TOPCon cells are increasingly valued as a new type of high-efficiency cell, and because the back of the TOPCon solar cell is a doped polysilicon layer structure, the doped polysilicon layer is basically not used on the front, so the heating unit only needs to be arranged opposite to the back of the TOPCon solar cell precursor, and the TOPCon solar cell precursor can be arranged on the furnace belt 50 with the back upward, at this time the heating unit 10 only needs to be arranged in the upper half of the sintering furnace cavity 20; and the TOPCon solar cell precursor is arranged on the furnace belt 50 with the back downward (the furnace belt 50 is a hollow furnace belt, such as a wire mesh), at this time the heating unit 10 only needs to be arranged in the lower half of the sintering furnace cavity 20 and penetrate the furnace belt 50 to heat the back of the TOPCon solar cell precursor.

[0072] As a specific embodiment, the arrangement density of the upper half or lower half of each temperature zone is determined according to the temperature requirement of the cell from the edge to the middle area, for example, in the sintering zone, the arrangement density of the heater can be set as follows: in 0-30°, 3 heaters are arranged in unit length along the traveling direction of the cell, in 30°-60°, 2 heaters are arranged, and in 60°-90°, 1 heater is arranged, so that the surface temperature of the cell in the sintering furnace cavity gradually decreases from the edge of the cell to the middle area of the cell, meeting the sintering temperature required by the inherent characteristics of different areas in the cell caused by the TOPCon front process equipment.

[0073] On the basis of the first specific embodiment, the density distribution of the heating unit 10 is further limited to obtain the third specific embodiment, and the structure diagram is shown in the structure diagram of the above specific embodiment, which includes a sintering furnace cavity 20, a furnace belt 50 and a heating unit 10.

[0074] The furnace belt 50 penetrates the sintering furnace cavity 20 along the length direction of the sintering furnace cavity 20 for transporting the solar cell precursor to be processed;

[0075] The heating unit 10 is arranged in the sintering furnace cavity 20 and surrounds the furnace belt 50;

[0076] The heating temperature of the heating unit 10 to the furnace belt 50 gradually decreases from the edge area of the furnace belt 50 to the middle area of the furnace belt 50;

[0077] The fresh air inlet 41 and the fresh air outlet 42 of the fresh air pipeline of the solar cell sintering furnace are arranged at the precursor inlet 21 of the sintering furnace cavity 20.

[0078] The difference between the present embodiment and the above embodiment is that the positions of the fresh air inlet 41 and the fresh air outlet 42 of the fresh air pipeline are defined in the present embodiment, and the rest of the structure is the same as that of the above embodiment, which will not be described here.

[0079] In the present embodiment, the fresh air inlet 41 and the fresh air outlet 42 of the fresh air pipeline are both arranged near the precursor inlet 21 of the sintering furnace cavity 20, please refer to Figure 2 The fresh air inlet 41 is a hole for absorbing external air, and the fresh air outlet 42 is a hole for discharging fresh air into the sintering furnace cavity 20. Of course, the fresh air outlet 42 is arranged outside the furnace, and the fresh air inlet 41 is arranged inside the furnace. The fresh air outlet 42 will form a positive pressure inside the furnace, and the fresh air inlet 41 will form a negative pressure outside the furnace. This makes the external cold air not directly enter the furnace through the precursor inlet 21 of the sintering furnace cavity 20 under the push and pull of the positive pressure / negative pressure, but preferentially enters the fresh air inlet 41, thereby ensuring that the precursor inlet 21 of the sintering furnace cavity 20 is in a long-term physical open state and does not worry about cold air directly entering to disturb the hot field, greatly facilitating the transportation of materials in the production process and improving the production efficiency.

[0080] Further, the fresh air inlet 41 is located outside the sintering furnace cavity 20, and the distance from the precursor inlet 21 is not more than 30 cm;

[0081] The fresh air outlet 42 is located inside the sintering furnace cavity 20, and the distance from the precursor inlet 21 is not more than 30 cm.

[0082] The above parameter range is the best range after a large number of theoretical calculations and actual tests. In the above range, less power consumption can form a better positive pressure / negative pressure effect, avoiding the direct entry of external cold air from the precursor inlet 21 of the sintering furnace cavity 20 into the furnace body. Of course, appropriate changes can also be made according to actual conditions.

[0083] Please refer to Figure 4 , Figure 4 is a schematic view of the conveying of the solar cell precursor. The solar cell precursor is first sent to the precursor inlet 21 by the front conveying belt shown in Figure 4 , and then transported forward by the furnace belt 50.

[0084] The present application also provides a sintering method of a solar cell, which is a sintering method of a solar cell using the solar cell sintering furnace as described above. The solar cell sintering furnace provided by the present application comprises a sintering furnace cavity 20, a furnace belt 50 and a heating unit 10; the furnace belt 50 runs through the sintering furnace cavity 20 along the length direction of the sintering furnace cavity 20, and is used for transporting the solar cell precursor to be processed; the heating unit 10 is arranged in the sintering furnace cavity 20 and surrounds the furnace belt 50; the heating temperature of the heating unit 10 to the furnace belt 50 gradually decreases from the edge area of the furnace belt 50 to the middle area of the furnace belt 50. The heating unit 10 is arranged in the sintering furnace cavity 20 and surrounds the solar cell precursor to radiate heat to the solar cell precursor from all directions, and by adjusting the heating temperature of the heating unit 10 to different positions of the furnace belt 50, the temperature of the edge position of the solar cell precursor is higher than that of the center position of the solar cell precursor, so that the metallization depth of the edge position is different from that of the center position in the sintering process, and the edge position can better cooperate with the boron diffusion junction, the tunnel layer and the doped polysilicon layer of different depths and thicknesses in the previous diffusion junction step, thereby improving the connection effect of the metal electrode, greatly reducing the EL defects such as black edge and area darkening of the solar cell, and improving the yield of the solar cell.

[0085] The embodiments are described in a progressive manner in the specification, and each embodiment focuses on the difference from other embodiments. For the device disclosed in the embodiments, the description is relatively simple because it corresponds to the method disclosed in the embodiments. For the relevant parts, refer to the description of the method.

[0086] It should be noted that, in the specification, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or sequence between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0087] The solar cell sintering furnace provided by the application is described in detail. The principle and implementation mode of the application are described by using specific examples, and the above description of the examples is only used to help understand the method of the application and the core idea. It should be pointed out that, for ordinary skilled persons in the technical field, some improvements and modifications can be made to the application without departing from the principle of the application, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A solar cell sintering furnace, characterized in that, Includes the sintering furnace cavity, furnace belt, and heating unit; The furnace belt runs through the sintering furnace cavity along the length of the sintering furnace cavity and is used to transport the solar cell precursor to be processed. The heating unit is disposed inside the sintering furnace cavity and surrounds the furnace belt; The heating temperature of the furnace belt by the heating unit gradually decreases from the edge region of the furnace belt to the middle region of the furnace belt; The sintering furnace cavity is an annular cavity; the heating unit is a heating lamp tube; The heating lamp is an annular lamp; the plane of the annular lamp is perpendicular to the length direction of the sintering furnace cavity. By adjusting the length-to-minor axis ratio of the sintering furnace cavity, different heating effects can be obtained for the edge and center positions of the solar cell precursor. The solar cell sintering furnace is a sintering furnace for sintering TOPCON cells.

2. The solar cell sintering furnace as described in claim 1, characterized in that, The heating lamp is a straight lamp whose extension direction is parallel to the length direction of the sintering furnace cavity.

3. The solar cell sintering furnace as described in claim 1, characterized in that, The sintering furnace cavity is an annular cavity; The density of the heating unit decreases as the angle between the laying position and the plane where the solar cell precursor is located increases.

4. The solar cell sintering furnace as described in claim 1, characterized in that, It also includes a heat exchange device; the heat exchange device includes a heat exhaust inlet, a heat exchange chamber, and a waste exhaust outlet. The hot exhaust gas from the sintering furnace cavity enters the heat exchange chamber through the hot exhaust inlet and is discharged through the exhaust outlet. The fresh air duct of the solar cell sintering furnace passes through the heat exchange chamber, allowing the fresh air from the external environment to exchange heat with the hot exhaust gas.

5. The solar cell sintering furnace as described in claim 4, characterized in that, The heat exchange device is located above the sintering furnace cavity; Accordingly, the hot exhaust inlet is located at the top of the sintering furnace cavity.

6. The solar cell sintering furnace as described in claim 4, characterized in that, The heat exchange device is a tubular heat exchange device; The tubular heat exchanger is arranged parallel to the sintering furnace cavity. The tubular heat exchanger includes multiple heat exhaust inlets, which are spaced apart along the length of the sintering furnace cavity.

7. The solar cell sintering furnace as described in claim 1, characterized in that, The heating unit is located only in the upper or lower half of the sintering furnace cavity and is opposite to the back of the solar cell precursor.

8. The solar cell sintering furnace according to any one of claims 1 to 7, characterized in that, The fresh air inlet and fresh air outlet of the fresh air duct of the solar cell sintering furnace are both located at the inlet of the precursor body of the sintering furnace cavity.

9. The solar cell sintering furnace as described in claim 8, characterized in that, The fresh air inlet is located outside the sintering furnace cavity and is no more than 30 centimeters away from the precursor inlet; The fresh air outlet is located inside the sintering furnace cavity and is no more than 30 centimeters away from the precursor inlet.

10. A sintering method for a solar cell, characterized in that, The solar cell is sintered using a solar cell sintering furnace as described in any one of claims 1 to 9.

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