Electromagnetic induction auxiliary sintering device

Abstract

The utility model provides an electromagnetic induction auxiliary sintering device which comprises a first temperature rising area and a second temperature rising area which are sequentially arranged in the conveying direction of an object to be heated, the first temperature rising area is provided with a constant heating assembly, the second temperature rising area is provided with an electromagnetic induction coil, and the constant heating assembly and the electromagnetic induction coil are arranged in the conveying direction of the object to be heated. The electromagnetic induction coils become dense from sparse. The electromagnetic induction coils become dense gradually, gradually-changed induction current can be generated on the surface layer of the to-be-heated object according to the electromagnetic induction principle, the surface layer of the to-be-heated object can be rapidly heated through generated heat, the temperature of the surface layer of the to-be-heated object is rapidly increased, and the sintering time can be shortened. When the to-be-heated object is conveyed to the sparse side of the electromagnetic induction coil, temperature sudden change does not exist, thermodynamic equilibrium is facilitated, and after the surface layer of the to-be-heated object is subjected to sintering treatment, morphology change is small; and more sintering conditions can be adapted by adjusting the density of the electromagnetic induction coils.

Description

Technical Field

[0001] The utility model relates to the field of sintering devices, in particular to an electromagnetic induction assisted sintering device. Background Art

[0002] The conductive paste of solar crystalline silicon cells is usually printed on the front and back of the cell by screen printing to form the electrodes and electric field of the cell. After printing the conductive paste, the morphology of the conductive grid lines will be fixed by high-temperature sintering. The morphology of the conductive grid lines is crucial to the performance of solar crystalline silicon cells, and the morphology of the conductive grid lines will affect the conversion efficiency of the cell. The morphology of the conductive grid lines obtained after sintering is mainly affected by the screen parameters and the sintering process. Generally, grid lines with good morphology can be printed through screen parameter design, but this good grid line morphology may deteriorate or even completely lose its advantage during the subsequent sintering process.

[0003] At present, the industry adopts the heat conduction method for sintering, that is, after the conductive paste is printed, the battery cell passes through a sintering furnace heated by a resistance wire or infrared. The sintering furnace contains different temperature zones, and the temperature gradually increases from low temperature and then gradually decreases to complete the sintering. Through this sintering method, the morphology of the conductive grid line changes greatly, the grid line expands outward and becomes wider, and the grid line will obviously collapse downward. Large deformation will increase the shading area and grid line resistance of the grid line, thereby adversely affecting the performance of the battery.

[0004] Therefore, the current sintering device still needs to be improved. Utility Model Content

[0005] The present invention aims to alleviate or solve at least one of the above-mentioned problems to at least a certain extent.

[0006] In one aspect of the utility model, the utility model provides an electromagnetic induction assisted sintering device. In some embodiments of the utility model, the electromagnetic induction assisted sintering device includes a first heating zone and a second heating zone arranged in sequence along the transmission direction of the object to be heated, the first heating zone has a constant heating component, the second heating zone has an electromagnetic induction coil, and along the transmission direction of the object to be heated, the electromagnetic induction coil changes from sparse to dense. Therefore, along the transmission direction of the object to be heated, the electromagnetic induction coil gradually changes from sparse to dense, and by utilizing the principle of electromagnetic induction, a gradual induced current can be generated on the surface layer of the object to be heated, and the heat generated can quickly heat the surface layer of the object to be heated, and the temperature of the surface layer of the object to be heated rises rapidly, which is beneficial to shortening the sintering time; the first heating zone is heated by a constant heating component, and the second heating zone is heated by an electromagnetic induction coil that changes from sparse to dense. When the object to be heated is transmitted to the sparser side of the electromagnetic induction coil, there will be no sudden temperature change, which is beneficial to maintaining the thermodynamic equilibrium of the surface layer. After the sintering treatment, the morphology of the surface layer of the object to be heated changes little, and the good morphology before sintering can be maintained; when the electromagnetic induction assisted sintering device is used for sintering, the density of the electromagnetic induction coil can be adjusted to adapt to more sintering situations and meet more sintering needs.

[0007] In some embodiments of the utility model, along the transmission direction of the object to be heated, the pitch of the electromagnetic induction coil changes from sparse to dense in equal proportion. The pitch of the coil changes in equal proportion, and the heating temperature can be increased in gradient along the transmission direction. After the object to be heated is treated, the morphology before sintering can be better maintained.

[0008] In some embodiments of the utility model, along the transmission direction of the object to be heated, the pitch of the electromagnetic induction coil changes from sparse to dense at a ratio of 0.5 to 0.9 times. Thus, the heating temperature can be gradually increased along the transmission direction, so that the object to be heated can better maintain the morphology before sintering after sintering.

[0009] In some embodiments of the utility model, along the transmission direction of the object to be heated, the pitch of the electromagnetic induction coil changes from sparse to dense in a ratio of 0.5 to 0.9 times. Thus, the heating temperature can be increased gradually along the transmission direction, and the temperature will not increase suddenly, which is more conducive to maintaining a good morphology of the object to be heated.

[0010] In some embodiments of the utility model, the electromagnetic induction assisted sintering device further includes a frequency conversion controller, which is used to pass an alternating current to the electromagnetic induction coil. By using the frequency conversion controller to pass an alternating current to the electromagnetic induction coil, a gradual induction current can be generated on the surface layer of the object to be heated using the electromagnetic induction principle. The heat generated can quickly heat the surface layer of the object to be heated, which is beneficial to shortening the sintering time and maintaining a good morphology of the object to be heated.

[0011] In some embodiments of the present invention, the constant heating component includes a resistance wire and / or an infrared heating source. Thus, the constant heating component can heat the object to be heated at a relatively low heating rate, so that the temperature of the object to be heated gradually increases.

[0012] In some embodiments of the present invention, the electromagnetic induction assisted sintering device further comprises a cooling zone, which is located on a side of the second heating zone away from the first heating zone. After being heated by the constant heating component and the electromagnetic induction coil, the object to be heated enters the cooling zone for cooling, thereby ending sintering.

[0013] In some embodiments of the present invention, the cooling zone is connected to the external environment. Therefore, after the object to be heated is transferred to the cooling zone, it can be quickly cooled at the external environment temperature, thereby better maintaining the morphology before sintering and shortening the processing time.

[0014] In some embodiments of the present invention, the electromagnetic induction assisted sintering device further comprises a transmission component, and the transmission component is used to transmit the object to be heated. The electromagnetic induction assisted sintering device has a transmission component, which is convenient for transmitting the object to be heated, so that the heated object can quickly complete the sintering process.

[0015] In some embodiments of the present invention, the electromagnetic induction assisted sintering device further includes a furnace body, and the first temperature rising zone and the second temperature rising zone are both located in the furnace body. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0017] Figure 1 A schematic diagram of the structure of an electromagnetic induction assisted sintering device according to an embodiment of the utility model is shown;

[0018] Figure 2 A schematic diagram showing the structure of an electromagnetic induction coil according to an embodiment of the utility model is shown;

[0019] Figure 3A partial structural schematic diagram of an electromagnetic induction assisted sintering device according to an embodiment of the utility model is shown;

[0020] Figure 4 A partial structural schematic diagram of an electromagnetic induction assisted sintering device according to another embodiment of the utility model is shown;

[0021] Figure 5 The figure shows a schematic structural diagram of an electromagnetic induction assisted sintering device according to another embodiment of the utility model.

[0022] Description of reference numerals:

[0023] 100: electromagnetic induction coil; 200: constant heating component; 300: frequency conversion controller; 400: furnace body; 10: first heating zone; 20: second heating zone; 30: cooling zone; 40: transmission component; 1: battery cell. DETAILED DESCRIPTION

[0024] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0025] The sintering furnaces currently used in the industry usually use resistance wire or infrared heating. Compared with before sintering, the morphology of the conductive grid lines after sintering changes greatly, the width increases greatly, and the height decreases more, and the good morphology before sintering cannot be well maintained. In order to at least alleviate or even solve at least one of the above problems to a certain extent, the utility model achieves faster sintering through a specific electromagnetic induction assisted sintering method, reduces the change in the morphology of the conductive grid lines after sintering, thereby reducing the shading and line resistance of the grid lines, and improving the conversion efficiency of the battery.

[0026] In one aspect of the present invention, the present invention provides an electromagnetic induction assisted sintering device. In some embodiments of the present invention, reference is made to Figures 1 to 5 The electromagnetic induction assisted sintering device may include a first heating zone 10 and a second heating zone 20 sequentially arranged along the transmission direction of the object to be heated, the first heating zone 10 having a constant heating component 200, and the second heating zone 20 having an electromagnetic induction coil 100, along the transmission direction of the object to be heated, that is, Figures 1 to 3 as well as Figure 5In the X direction shown in , the electromagnetic induction coil 100 changes from sparse to dense. Therefore, when an alternating current is passed through the electromagnetic induction coil, a high-density gradient induction current can be generated on the surface layer of the object to be heated by utilizing the electromagnetic induction principle. The heat generated thereby can quickly heat the surface layer of the object to be heated, and the temperature rises rapidly, which is beneficial to shortening the heating time. At the same time, a constant heating component is first used for heating in the first heating zone, and then, when entering the second heating zone, the design of the electromagnetic induction coil changing from sparse to dense will not cause a sudden change in the temperature of the object to be heated, which is beneficial to maintaining the thermodynamic balance during the heating process of the object to be heated, so that the object to be heated can maintain a good morphology before sintering after sintering; the density of the electromagnetic induction coil can be adjusted to adapt to more sintering situations and meet more sintering requirements.

[0027] In some specific embodiments of the present invention, a constant heating component can be used to heat the object to be heated first, so that its temperature rises to a certain value (lower temperature), and then an electromagnetic induction coil can be used to heat the object to be heated, so that its temperature rises rapidly. The design of the electromagnetic induction coil from sparse to dense can prevent the temperature of the object to be heated from changing suddenly, thereby allowing the object to be heated to maintain a good morphology after sintering.

[0028] In some embodiments of the utility model, the battery induction assisted sintering device can be used to heat the battery cell. The battery cell first enters the first temperature rising zone and is heated by a constant heating component. After that, the battery cell enters the heating area corresponding to the electromagnetic induction coil. By utilizing the principle of electromagnetic induction, a high-density gradient induced current can be generated on the surface layer of the battery conductive paste. The heat generated can quickly heat the surface layer of the conductive paste, so that the conductive paste can quickly obtain heat and reach a high-temperature melting state, shortening the heating time. At the same time, when the battery cell enters the area corresponding to the coil, the design of the gradient coil will not cause a sudden change in the temperature of the conductive paste, which is conducive to maintaining the thermodynamic equilibrium of the paste, and the morphology of the conductive grid line after printing can be well maintained.

[0029] In some embodiments of the present invention, along the transmission direction of the object to be heated, the pitch of the electromagnetic induction coil changes from sparse to dense in equal proportion. Figure 1 , along the X direction, the pitch between the nth turn and the n+1th turn of the electromagnetic induction coil 100 is denoted as d n The pitch between the n+1th turn and the n+2th turn of the electromagnetic induction coil 100 is denoted as d n+1 , d n+1 With d n The ratio of can be a constant, and d n+1 With d nThe ratio is less than 1. The pitch of the electromagnetic induction coil changes from sparse to dense in equal proportion. When the electromagnetic induction coil is used to heat the battery cell, the heating temperature can be increased gradually along the transmission direction without causing a sudden change in the temperature of the conductive paste, which is beneficial to maintaining a good morphology of the conductive grid line after printing. In addition, the temperature of the conductive paste on the battery cell can be increased quickly, which is beneficial to shortening the sintering time.

[0030] In some embodiments of the present invention, along the transmission direction of the object to be heated (X direction), the pitch of the electromagnetic induction coil 100 can be changed from sparse to dense at a ratio of 0.5 to 0.9 times. For example, the pitch of the electromagnetic induction coil 100 can be changed from sparse to dense at a ratio of 0.5, 0.6, 0.7, 0.8, or 0.9 times. Figure 1 , d n+1 With d n The ratio of can be 0.5 to 0.9. When n takes different values, the ratio can be the same or different. The pitch changes from sparse to dense according to the above ratio, so that the heating temperature gradually rises along the transmission direction of the object to be heated, and the temperature of the object to be heated does not change suddenly, which is conducive to maintaining a good morphology.

[0031] In some embodiments of the present invention, along the transmission direction of the object to be heated, the pitch of the electromagnetic induction coil 100 can be changed from sparse to dense in a ratio of 0.5 to 0.9 times. As a result, along the transmission direction of the object to be heated, the heating temperature gradient increases, and the object to be heated can be heated quickly, and the temperature of the object to be heated will not change suddenly, which is more conducive to maintaining a good morphology. In some specific embodiments of the present invention, reference Figure 1 and Figure 2 , along the X direction, the pitch of the electromagnetic induction coil 100 can be changed from sparse to dense in a ratio of 0.5 to 0.9 times. When n takes different values, d n+1 With d n The ratio is a fixed value and is in the range of 0.5 to 0.9. Figure 2 , d 2 / d 1 =d 3 / d 2 =d 4 / d 3 =d 5 / d 4 =0.5~0.9.

[0032] In some specific embodiments of the present invention, the constant heating component 200 may include a resistance wire and / or an infrared heating source. The use of resistance wire and / or infrared heating can increase the temperature of the object to be heated, which is beneficial to the subsequent sintering process. In the present invention, the number of constant heating components 200 in the first temperature rise zone 10 is not specifically limited. Those skilled in the art can set one or more constant heating components 200 in the first temperature rise zone 10 according to actual needs. When multiple constant heating components 200 are set in the first temperature rise zone 10, the types of the multiple constant heating components 200 can be the same or different.

[0033] In some embodiments of the present invention, reference Figure 3 The electromagnetic induction assisted sintering device may further include a transmission component 40, which is used to transmit the object to be heated. In some specific embodiments of the present invention, the transmission component 40 may be a transmission belt.

[0034] In some embodiments of the present invention, reference Figure 4 The electromagnetic induction assisted sintering device may further include a frequency conversion controller 300, which may be used to pass an alternating current into the electromagnetic induction coil 100. By using the frequency conversion controller to pass an alternating current into the coil, the alternating current is more controllable and more conducive to rapidly heating the object to be heated.

[0035] In some embodiments of the present invention, reference Figure 3 and Figure 5 The electromagnetic induction assisted sintering device further includes a cooling zone 30, which is located on the side of the second heating zone 20 away from the first heating zone 10. In the transmission direction (X direction) of the object to be heated, the first heating zone 10, the second heating zone 20 and the cooling zone 30 are arranged in sequence. Figure 3 and Figure 5 The object to be heated (eg, the battery cell 1) is heated at a lower rate in the first temperature rising zone 10, and after entering the second temperature rising zone 20, is heated at a higher rate, and then enters the cooling zone to cool down, completing the sintering process.

[0036] In some specific embodiments of the present invention, reference is made to Figure 3 and Figure 5 After the battery cell 1 is heated by the constant heating component 200 and the electromagnetic induction coil 100 in sequence, it is transferred to the cooling zone 30 by the transmission component 40 for cooling to complete the sintering process.

[0037] In some embodiments of the present invention, the cooling zone 30 can be connected to the external environment, so that after the heating treatment, the object can be quickly cooled in the cooling zone, which is more conducive to maintaining a good morphology. In some specific embodiments of the present invention, the external environment can be indoor air, and the object can be quickly cooled in the room temperature air of the cooling zone.

[0038] In some embodiments of the present invention, reference Figure 5 The electromagnetic induction assisted sintering device may further include a furnace body 400 , the first temperature rising zone 10 and the second temperature rising zone 20 may both be located in the furnace body 400 , and the constant heating assembly 200 and the electromagnetic induction coil 100 may both be located in the furnace body 400 .

[0039] In some embodiments of the present invention, reference Figure 5 , the cooling zone 30 may be located in the furnace body 400. In other embodiments of the present invention, the cooling zone may be located outside the furnace body.

[0040] In some specific embodiments of the present invention, the battery cell 1 can be heated to about 300°C in the first temperature rising zone 10, and heated from about 300°C to about 800°C in the second temperature rising zone 20. The conductive paste can begin to melt at about 500°C and completely melt at 800°C, and then quickly cool in room temperature air in the cooling zone 30.

[0041] The utility model is described below by specific embodiments, and it will be appreciated by those skilled in the art that the following specific embodiments are only for the purpose of illustration, and do not limit the scope of the utility model in any way. In addition, in the following embodiments, unless otherwise specified, the materials and equipment used are all commercially available. If in the following embodiments, specific processing conditions and processing methods are not clearly described, then conditions and methods known in the art can be used for processing.

[0042] For PERC (Passivated Emitter back contact) cells, the average width of the gate lines after screen printing is 25.0-26.0 μm, and the average height is 15-16 μm. The same batch of PERC cells is used for sintering in the comparative example and the embodiment.

[0043] In comparative example 1, the sintering furnace in the prior art is used for sintering, and the resistance wire is used for heating. The temperature of the sintering furnace is increased from room temperature to the sintering peak temperature, and the sintering process time is 20-30 seconds. After sintering, the average width of the gate line is 27.0-29.0 μm, and the average height is 12-14 μm.

[0044] In comparative example 2, the sintering furnace in the prior art is used for sintering, and infrared heating is adopted. The temperature of the sintering furnace is increased from room temperature to the sintering peak temperature, and the sintering process time is 20 to 29 seconds. After sintering, the average width of the gate line is 26.9 to 28.7 μm, and the average height is 12.4 to 14.1 μm.

[0045] In the embodiment, a pitch gradient coil is set in the sintering furnace, and sintering is performed by electromagnetic induction assisted heating, wherein the pitch of the electromagnetic induction coil is arranged from sparse to dense at a ratio of 0.8 times along the transmission direction of the battery cell, and the printed conductive grid line is first heated by a resistance wire, and then the conductive grid line is quickly heated to the sintering peak temperature by a gradient coil, and then quickly cooled in room temperature air through a conveyor belt. The sintering process time is shortened to 10-15s, and the average width of the grid line after sintering is 25.2-26.2μm, and the average height is 14.5-15.5μm.

[0046] Through the comparison of the above data, it can be seen that when the electromagnetic induction assisted sintering device proposed by the utility model is used to sinter the battery cell, the morphology of the grid line can be better maintained.

[0047] In general, the electromagnetic induction assisted sintering device proposed in the utility model can realize the rapid sintering of the conductive grid line, and will not cause a sudden change in the temperature of the conductive slurry, which is conducive to maintaining the thermodynamic equilibrium of the slurry; the grid line after sintering can maintain a good morphology, and the sintering process time is greatly shortened. Compared with the prior art, the electromagnetic induction assisted sintering device proposed in the utility model is used to sinter the battery cell, and the grid line after sintering is thinner, which is conducive to reducing the shading area, and the height of the grid line is higher, which is conducive to reducing the resistance of the grid line, thereby helping to improve the conversion efficiency of solar crystalline silicon cells.

[0048] In the description of the present invention, the terms "upper", "lower", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0049] In the description of this specification, the description with reference to the terms "one embodiment", "another embodiment", "some embodiments" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment are included in at least one embodiment of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory. In addition, it should be noted that in this specification, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

[0050] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An electromagnetic induction assisted sintering device, characterized in that: It comprises a first heating zone and a second heating zone arranged in sequence along the transmission direction of the object to be heated, wherein the first heating zone has a constant heating component, and the second heating zone has an electromagnetic induction coil, and along the transmission direction of the object to be heated, the electromagnetic induction coil changes from sparse to dense.

2. The electromagnetic induction assisted sintering device according to claim 1, characterized in that: Along the transmission direction of the object to be heated, the pitch of the electromagnetic induction coil changes from sparse to dense in equal proportion.

3. The electromagnetic induction assisted sintering device according to claim 1, characterized in that: Along the transmission direction of the object to be heated, the pitch of the electromagnetic induction coil changes from sparse to dense at a ratio of 0.5 to 0.9 times.

4. The electromagnetic induction assisted sintering device according to claim 1, characterized in that: Along the transmission direction of the object to be heated, the pitch of the electromagnetic induction coil changes from sparse to dense in a ratio of 0.5 to 0.9 times.

5. The electromagnetic induction assisted sintering device according to any one of claims 1 to 4, characterized in that: The electromagnetic induction assisted sintering device further comprises a frequency conversion controller, which is used to pass an alternating current into the electromagnetic induction coil.

6. The electromagnetic induction assisted sintering device according to any one of claims 1 to 4, characterized in that: The constant heating component includes a resistance wire and / or an infrared heating source.

7. The electromagnetic induction assisted sintering device according to any one of claims 1 to 4, characterized in that: The electromagnetic induction assisted sintering device further includes a cooling zone, which is located on a side of the second temperature rising zone away from the first temperature rising zone.

8. The electromagnetic induction assisted sintering device according to claim 7, characterized in that: The cooling zone is in communication with the external environment.

9. The electromagnetic induction assisted sintering device according to any one of claims 1 to 4 and 8, characterized in that: The electromagnetic induction assisted sintering device further comprises a transmission component, and the transmission component is used for transmitting the object to be heated.

10. The electromagnetic induction assisted sintering device according to any one of claims 1 to 4 and 8, characterized in that: The electromagnetic induction assisted sintering device further comprises a furnace body, and the first temperature rising zone and the second temperature rising zone are both located in the furnace body.

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