Apparatus and method for pre-treating flat-type fuel cell stack by using high-frequency induction heating

Abstract

The present invention relates to an apparatus and a method for pre-treating a flat-type fuel cell stack by using high-frequency induction heating. The apparatus for pre-treating a stack of a stacked structure, including at least one cell, a separation plate provided between every two cells such that a plurality of cells can be stacked, and a sealing material disposed between the cell and the separation plate in order to maintain gas tightness, comprises: a heating coil wound a plurality of times to surround the periphery of the stack without being in contact with the outside of the stack, thereby enabling induced current to be generated; a high frequency generator, which supplies a high frequency current to the heating coil so as to heat the stack with heat generated by the induced current, thereby inducing bonding of the sealing material; and a high frequency controller connected to the high frequency generator so as to control the frequency range of the induced current, thereby allowing the sealing material to be heated to a temperature at which thermal bonding is possible.

Description

Pretreatment device and method for a flat fuel cell stack using high-frequency induction heating

[0001] The present invention relates to a pretreatment device and method for a flat fuel cell stack using high-frequency induction heating, and more specifically, to a pretreatment device and method for a flat fuel cell stack capable of excellent pretreatment by simultaneously forming a sealing structure of the stack using high-frequency induction heating.

[0002] A fuel cell is a power generator that generates water and electricity through an electrochemical reaction between hydrogen (fuel) and oxygen. It uses a stacked structure in which multiple power generation units, each consisting of a unit cell and a separator, are stacked.

[0003] A unit cell includes an electrolyte membrane, an anode (air electrode) located on one side of the electrolyte membrane, and a cathode (fuel electrode) located on the other side of the electrolyte membrane. The name and operating temperature of the fuel cell are distinguished depending on the electrolyte material.

[0004] A solid oxide fuel cell (SOFC) is one in which oxygen from the air electrode moves to the fuel electrode in the form of ions through a solid electrolyte. As shown in Fig. 1, a typical flat-plate SOFC has a laminated structure of a unit cell (12) and a separator (STS) (14).

[0005] A sealant (16) is placed between the cell (12) and the separator (14) to maintain gas tightness. The sealant (16) is composed of glass or a combination of glass and ceramic, and is manufactured in a slurry state by including a binder component to apply the glass powder in a desired shape.

[0006] The conventional pretreatment process is to place the stack in an electric furnace and raise the temperature to remove the binder component contained in the sealant (16) at around 200 to 400°C, and further raise the temperature to soften the sealant at around 600 to 800°C, during which shrinkage occurs in the height direction of the stack.

[0007] That is, when the temperature is raised to about 200 to 400°C, the binder component contained in the sealant (16) is removed. As the binder component is removed, the volume of the sealant (16) changes, so the height of the stack changes overall and even becomes warped or crooked.

[0008] In this way, in the case of an electric furnace, it is not easy to secure temperature uniformity due to convection in the internal space and pretreatment gas, etc., so there was a problem that the stack did not shrink uniformly in the height direction during the pretreatment process, resulting in a normal sealing structure and a uniform stack surface pressure not being formed.

[0009] In addition, the heat transfer rate is slow and the electric furnace must be heated above a certain level to provide sufficient heat, which results in high energy consumption, and there are problems such as the separator shrinking and deforming when excessive heat is applied due to the inability to secure temperature uniformity.

[0010] The present invention has been devised to solve the above problems, and its purpose is to provide a pretreatment device and method for a flat fuel cell stack using high-frequency induction heating, which can form a normal sealing structure and uniform stack surface pressure by ensuring temperature uniformity during the pretreatment process so that the stack can be uniformly shrunk in the height direction.

[0011] In addition, the purpose is to provide a pretreatment device and method for a flat fuel cell stack that can significantly reduce the time required for the pretreatment process by rapidly increasing the pretreatment temperature using high-frequency induction heating, thereby enabling simultaneous pretreatment, and can increase energy efficiency and prevent excessive heat from being applied to the separator and binder.

[0012] In order to achieve the above object of the present invention, the present invention provides a pretreatment device for a flat fuel cell stack using high-frequency induction heating, comprising: a device for pretreating a stack having a laminated structure comprising one or more cells, a separator installed between each cell so that a plurality of cells can be stacked, and a sealant disposed between the cells and the separator to maintain gas tightness; a heating coil wound multiple times so as to surround the periphery of the stack without contacting the exterior of the stack so as to generate an induced current; a high-frequency generator for supplying a high-frequency current to the heating coil to heat the stack with heat generated by the induced current to induce bonding of the sealant; and a high-frequency controller connected to the high-frequency generator to control a frequency range of the induced current so as to heat the sealant to a temperature at which heat fusion is possible.

[0013] In the present invention, a heating case made of a metallic material is further included so as to be heated by an induced current generated from the heating coil on the outside of the stack.

[0014] The above heating case may have a square prism shape to match the shape of the stack or a cylindrical shape corresponding to the shape of the coil.

[0015] Meanwhile, the inner surface of the heating case may be formed of a reflector to ensure temperature uniformity in the stack using radiant heat.

[0016] In the present invention, the heating coil is configured to locally heat the stack so that a heating zone is formed in a portion of the stack, and a vertical transport unit may be further installed to provide a driving force to transport the heating coil or the stack in the height direction.

[0017] The above-mentioned upper and lower conveying unit may have a different moving speed depending on the characteristics of the sealing material or the temperature range to be heated in the sealing material, and a separate speed control unit may be further provided to control the moving speed of the upper and lower conveying unit.

[0018] Meanwhile, the heating coil is composed of a plurality of coils divided into at least two sections in the height direction of the stack, and a high-frequency generator that supplies high-frequency current to each coil and a high-frequency controller that is connected to the high-frequency generator and controls the frequency range of the induced current are separately connected, so that different heating temperature conditions can be applied to each coil as needed.

[0019] The high-frequency controller is characterized in that it controls the frequency range of the induced current in stages so as to raise the temperature to a first temperature at which the binder component included in the sealant is removed, or to raise the temperature to a second temperature at which the sealant is softened and heat-sealed.

[0020] In addition, the heating coil is wound in a size and shape corresponding to the external shape of the stack in a 'ㅁ' shape on a plane, and may be installed at a predetermined distance from the stack.

[0021] Meanwhile, in order to achieve the above-described object of the present invention, a method for pretreating a stack using a pretreating device of a flat-plate fuel cell stack is provided, comprising the steps of: (a) positioning the stack inside a heating coil on which a pretreating process is to be performed; (b) supplying an alternating current to the heating coil from a high-frequency generator that supplies a high-frequency current to raise the temperature to a first temperature by a magnetic field generated in the heating coil to remove a binder component contained in a sealant; (c) supplying an alternating current to the heating coil from the high-frequency generator to further raise the temperature by a magnetic field generated in the heating coil to inductively heat the sealant to a second temperature at which the sealant is softened and can be heat-sealed; and (d) forming a complete sealing structure in which the sealant is heat-sealed between a cell and a separator to maintain a gas-tight seal.

[0022] The above first temperature has a temperature range of 200 to 400°C capable of removing the binder component contained in the sealant, and the above second temperature has a temperature range of 600 to 800°C capable of softening the sealant and allowing heat sealing.

[0023] Here, the heating coil is configured to locally heat the stack so that a heating zone is formed in a portion of the stack, and the stack can be locally sealed while the heating coil is transported by a vertical transport unit that transports the heating coil in the height direction of the stack.

[0024] In addition, the heating coil is characterized by being composed of a plurality of coils divided into at least two sections in the height direction of the stack, and a high-frequency generator for supplying high-frequency current to each coil and a high-frequency controller connected to the high-frequency generator and controlling the frequency range of the induced current are separately connected, so that different heating temperature conditions are applied to each coil as needed, and each coil sequentially performs steps (b) and (c) to be sealed.

[0025] According to the present invention as described above, heating for sealing the stack is performed almost simultaneously, thereby ensuring temperature uniformity during the pretreatment process, and by allowing the stack to shrink uniformly in the height direction, there is an effect of forming a normal sealing structure and uniform stack surface pressure.

[0026] In addition, by rapidly increasing the pretreatment temperature using high-frequency induction heating, the time required for the pretreatment process can be significantly reduced, energy efficiency can be increased, and excessive heat can be prevented from being applied to the separator and binder.

[0027] Figure 1 is an exploded perspective view showing the configuration of a conventional general flat-plate SOFC.

[0028] Figures 2 and 3 are diagrams illustrating a first embodiment according to the present invention, in which one heating coil is installed.

[0029] Figure 4 is an exploded perspective view illustrating a second embodiment according to the present invention.

[0030] Figure 5 is a schematic diagram illustrating a third embodiment according to the present invention.

[0031] Figure 6 is a configuration diagram illustrating a fourth embodiment according to the present invention.

[0032] FIG. 7 is a flowchart for explaining a pretreatment method of a flat fuel cell stack using high-frequency induction heating according to one embodiment of the present invention.

[0033] Figures 8 and 9 are graphs showing data for setting the temperature range of the first temperature and the second temperature according to the present invention.

[0034] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. First, when assigning reference numerals to components in each drawing, it should be noted that, where possible, identical components are assigned the same numerals even if they are shown in different drawings. In this case, the configuration and operation of the present invention depicted in and described by the drawings are described as at least one embodiment, and the technical concept of the present invention and its core configuration and operation are not limited thereby.

[0035] Figures 2 and 3 are diagrams illustrating a first embodiment according to the present invention, in which one heating coil is installed.

[0036] The present invention relates to a device and method for pretreating a flat fuel cell stack using high-frequency induction heating, and to a pretreating device and method using high-frequency induction heating so as to form a stack (10) with a completely sealed structure, which comprises a plurality of cells, a separator installed between each cell so as to stack the cells, and a sealant disposed between the cells and the separator to maintain gas tightness.

[0037] As shown in Fig. 2, the pretreatment device of a flat fuel cell stack using high-frequency induction heating of the present invention is equipped with a heating coil (20) that is wound multiple times to surround the stack (10) so as to generate an induced current.

[0038] A high frequency generator (30) that supplies high frequency current is connected to the above heating coil (20), and a high frequency controller (40) that controls the frequency range of the induced current is connected to the high frequency generator (30).

[0039] High-frequency induction heating means forming a magnetic field in a conductor such as a metal located in a coil through which an alternating current (high-frequency) flows, thereby generating an induced current (eddy current) in the object to be heated, thereby inducing Joule heat generation due to the inherent resistance of the object to be heated and the eddy current. This eddy current has a skin effect in which the current density is greater the closer it is to the surface of the object to be heated (near the coil) and decreases as it goes toward the center, that is, local heating near the surface of the object to be heated is possible, and the skin effect becomes greater as the frequency increases.

[0040] In addition, since control is performed by electrical means such as output voltage, frequency, and current phase angle, high-speed response control is easy, making it very advantageous for use in sealing stacks.

[0041] Typically, the sealant is located near the edge of the cell (the side of the stack), and the separator is made of a metal material (STS), so when combined with the characteristics of this high-frequency induction heating, excellent pretreatment of the flat-plate SOFC stack is possible.

[0042] In particular, as shown in Fig. 2, when the stack (10) is positioned in the middle of the induction heating coil (20), pretreatment at a more uniform temperature is possible for the entire stack (10) due to the formation of a uniform magnetic flux.

[0043] Here, the heating coil (20) is wound multiple times so as to surround the stack (10) without contacting the outside thereof, thereby generating an induced current, and the high-frequency generator (30) supplies a high-frequency current to the heating coil (20) to heat the stack with the heat generated by the induced current, thereby inducing bonding of the sealing material.

[0044] In addition, the heating coil may be wound in a size and shape corresponding to the external shape of the stack in a 'ㅁ' shape on a plane rather than a circle, and in this case, it may be installed at a predetermined distance from the stack. When the heating coil is wound on the outside of the stack in a 'ㅁ' shape on a plane, the gap between the sealant and the heating coil is uniform, so that the heat applied to the sealant can be more uniform.

[0045] The present invention further comprises a high frequency controller (40) connected to the high frequency generator (30) to control the frequency to a temperature at which the sealing material can be heat-sealed.

[0046] Control is performed electrically through the high frequency controller (40), and the high frequency controller (40) controls the frequency range of the induced current so as to heat the sealant to a temperature at which heat fusion is possible.

[0047] In the present invention, when controlling the heating temperature through the high-frequency controller (40), a two-stage temperature control can be performed: a first temperature for removing the binder component within the sealant, and a second temperature for softening the sealant and causing it to be thermally fused.

[0048] The first temperature preferably has a temperature range of 200 to 400°C at which the binder component contained in the sealant can be removed, and the second temperature preferably has a temperature range of 600 to 800°C at which the sealant can be softened and heat-sealed.

[0049] The above sealant is composed of glass or a combination of glass and ceramic, and is produced in a slurry state by including a binder component to apply glass powder in a desired shape. The binder is usually removed by volatilization when the temperature is raised to about 200 to 400°C.

[0050] At this time, temperature control for removing the binder component is very important because the volume of the sealant changes as the binder component is removed.

[0051] In the present invention, the high frequency generator (30) converts the frequency of the power source controlled by the high frequency controller (40) into a high frequency current and supplies the high frequency current to the heating coil (20) to instantly apply heat to the stack and ensure temperature uniformity, so that it is possible to uniformly heat to a temperature capable of removing the binder component, and the temperature can be controlled according to the type or characteristics of the binder, and by further increasing the temperature to around 600 to 800°C, the sealant softens and heat-sealing is possible.

[0052] This invention can increase energy efficiency and prevent excessive heat from being applied to the separator and binder due to temperature control through a high-frequency controller (40).

[0053] Meanwhile, FIG. 4 is an exploded perspective view illustrating a second embodiment according to the present invention, in which a heating case (50) made of a metallic material that is heated by an induced current generated from the heating coil (20) on the outside of the stack (10) can be further installed.

[0054] The above heating case (50) is a heating element made of metal that receives an induced current and generates heat. As shown in FIG. 4, in order to increase the contact area with the stack (10), it can have a square pillar shape to match the shape of the stack.

[0055] Additionally, it may be formed into a cylindrical shape corresponding to the shape of the heating coil (20).

[0056] A heating coil (20) that generates an induced current by a high-frequency current is wound and installed on the outer surface of the heating case (50), and when the high-frequency generator (30) supplies a high-frequency current to the heating coil (20), heat is generated by the induced current, and the heating case (50) is heated to heat the stack, thereby inducing bonding of the sealing material.

[0057] Meanwhile, the inner surface of the heating case (50) may be formed of a reflector to ensure temperature uniformity in the stack (10) by using radiant heat, or a separate reflector may be installed.

[0058] In this way, the present invention, which has a reflector provided on the inner surface of the heating case (50), can enable the heat to be more uniformly heated in the stack (10) when the high-frequency current is supplied, and can enable a normal sealing structure and uniform stack surface pressure to be formed.

[0059] Figure 5 is a schematic diagram illustrating a third embodiment according to the present invention.

[0060] In the present invention, the heating coil (20) may be configured to locally heat the stack (10) so that a heating zone is formed in a portion of the stack (10).

[0061] That is, the heating coil (20) is not wound around the stack (10) to correspond to the entire height of the stack (10), but rather the heating coil (20) is wound only over a portion of the stack (10).

[0062] In this case, the heating coil (20) can locally heat the stack (10), and an upward transport unit (60) that provides driving force to transport the heating coil (20) or the stack (10) in the height direction can be further installed.

[0063] The above-mentioned vertical transport unit (60) can be applied in various ways as long as it provides driving force to transport the heating coil (20) or stack (10) in the height direction, and known technologies can be applied.

[0064] For example, a structure that elevates using a motor and gears is possible, and a structure that elevates using a cylinder method is also possible.

[0065] In the present invention, as an example, as shown in FIG. 4, an elevation table (62) formed to support the heating coil (20) and allow the stack (10) to pass through, and a vertical transport unit (60) including a hydraulic cylinder (64) that allows the elevation table (62) to be elevated are shown.

[0066] In this invention, the heating coil (20) is raised and lowered by the upper and lower conveyor (60), and the heating coil (20) can locally heat the stack (10), so that the entire area of ​​the stack (10) can be sequentially heated, and uniform pretreatment can be performed.

[0067] In addition, a configuration in which the stack (10) is moved up and down while the heating coil (20) is fixed is also possible, and by locally heating the stack (10), the stack can be pretreated at a uniform temperature, thereby enabling excellent volatilization of the binder and thermal fusion of the sealant.

[0068] In this case, the upper and lower conveying unit (60) may be further provided with a separate speed control unit that controls the conveying speed so that the moving speed can be varied depending on the characteristics of the sealing material or the temperature range to be heated in the sealing material.

[0069] Meanwhile, the heating coil (20) may be composed of a plurality of coils divided into at least two parts in the height direction of the stack (10).

[0070] FIG. 6 is a configuration diagram showing a fourth embodiment according to the present invention, in which the heating coils (22) (24) (26) are installed in three sections in the height direction of the stack (10), and a high-frequency generator (32) (34) (36) and a high-frequency controller (42) (44) (46) that supply high-frequency current to each coil (22) (24) (26) are separately connected, so that different heating temperature conditions can be applied to each coil as needed.

[0071] The high-frequency controller (42)(44)(46) can control the frequency range of the induced current in stages to raise the temperature to a first temperature at which the binder component included in the sealant is removed, or to a second temperature at which the sealant is softened and heat-sealed, so that the temperature of each heating coil (22)(24)(26) can be raised through temperature control for each section.

[0072] For example, when preprocessing is performed stepwise (locally) from the bottom to the top of the stack (10), preprocessing is performed by starting from the coil (22) wound at the bottom of the stack (10).

[0073] Typically, stacks are subject to vertical pressure, with the lower portion of the stack experiencing greater pressure than the upper portion. Therefore, rather than applying heat for binder volatilization or sealant thermal bonding to both the upper and lower portions of the stack simultaneously, it is preferable to conduct separate heating processes for the upper and lower portions. Furthermore, it is preferable to heat-bond the sealant starting from the lower portion, where pressure is greatest.

[0074] Accordingly, the heating coil (20) is installed in multiple sections in the height direction of the stack (10), and a high-frequency generator and a high-frequency controller capable of high-frequency induction heating are separately installed for each coil, thereby enabling section-wise heating. This configuration enables uniform shrinkage of the stack in the height direction during the pretreatment process, and enables a normal sealing structure.

[0075] The pretreatment method of the pretreatment device of the flat fuel cell stack using high-frequency induction heating of the present invention having such a configuration is described as follows.

[0076] FIG. 7 is a flowchart for explaining a pretreatment method of a flat fuel cell stack using high-frequency induction heating according to an embodiment of the present invention. First, the stack (10) is positioned inside a heating coil (20) where a pretreatment process is to be performed (S110).

[0077] In this case, a heating case (50) may be additionally installed outside the stack.

[0078] Here, the heating coil may be installed so as to heat the entire area of ​​the stack as described above, or may be configured so as to locally heat the stack so as to form a heating zone in a portion of the stack.

[0079] When a heating coil is installed to form a heating zone in a portion of the stack, a vertical transport unit for transporting the heating coil or stack in the height direction may be further installed.

[0080] In addition, the heating coil may be composed of a plurality of coils divided into at least two sections in the height direction of the stack, and a high-frequency generator supplying high-frequency current to each coil and a high-frequency controller connected to the high-frequency generator and controlling the frequency range of the induced current may be separately connected, so that different heating temperature conditions may be applied to each coil as needed.

[0081] After positioning the above stack inside the heating coil, an alternating current is supplied to the heating coil (20) from a high frequency generator (30) that supplies high frequency current, thereby raising the temperature to a first temperature by a magnetic field generated in the heating coil, thereby removing the binder component included in the sealant (S120).

[0082] The binder component included in the sealant is removed by volatilization when the temperature is raised to about 200 to 400°C, and in the present invention, the binder component is removed by heating the heating coil to a first temperature for removing the binder component.

[0083] Here, the volatilization temperature of the above binder component can be controlled differently depending on its characteristics and type, and the binder removal process can be performed by dividing it into multiple stages rather than one stage.

[0084] Afterwards, an alternating current is supplied to the heating coil from the high frequency generator (30) to further increase the temperature by the magnetic field generated in the heating coil, thereby softening the sealant and inductively heating it to a second temperature at which heat fusion is possible (130).

[0085] The above second temperature is characterized by having a temperature range of 600 to 800°C at which the sealant is softened and heat-sealed.

[0086] In this way, when the sealing material is heat-sealed between the cell and the separator, a complete sealing structure capable of maintaining gas tightness is formed (S140).

[0087] Figures 8 and 9 are graphs showing data for setting the temperature range of the first temperature and the second temperature according to the present invention, and Figure 8 shows a TGA curve of an organic binder.

[0088] As shown in Fig. 8, the organic binder volatilization range is 180 to 550°C, and it can be seen that the weight decreases rapidly from 100% around 250°C, indicating that a phase change of the organic binder occurs.

[0089] Therefore, when the sealant of the present invention is heated to around 250°C, the binder contained in the sealant is removed as it volatilizes.

[0090] Additionally, Figure 9 shows a TGA curve of a specific glass powder. As the temperature gradually increases, the glass powder melts. When it passes the softening temperature, it melts and becomes liquid, sealing the gaps between the powders. The softening temperature refers to the temperature at which it completely changes to a liquid state.

[0091] As seen in Fig. 9, the phase change begins at about 600°C, and the shrinkage range of the glass powder due to softening temperature is 600 to 850°C.

[0092] The softening temperature of the glass powder was measured to be 703.4℃ for RC-1, 652.6℃ for KG750, and 792.5℃ for Pyrex, depending on the type. Therefore, in the present invention, the temperature range of 600 to 800℃ as the second temperature at which the sealant softens and can be thermally fused is a temperature range set to match the shrinkage section of 600 to 850℃ due to the softening temperature of the glass powder.

[0093] The present invention utilizes high-frequency induction heating to achieve almost simultaneous heating for sealing the stack, thereby ensuring temperature uniformity during the pretreatment process and enabling the stack to shrink uniformly in the height direction, thereby having the effect of forming a normal sealing structure and uniform stack surface pressure.

[0094] In addition, by rapidly increasing the pretreatment temperature using high-frequency induction heating, the time required for the pretreatment process can be significantly reduced, energy efficiency can be increased, and excessive heat can be prevented from being applied to the separator and binder.

[0095] The above description is merely an illustrative illustration of the technical idea of ​​the present invention, and those skilled in the art can make various modifications and variations without departing from the essential characteristics of the present invention. In addition, the embodiments disclosed in the present invention are not intended to limit the technical idea of ​​the present invention, but rather to explain it, and the scope of the technical idea of ​​the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. A device for preprocessing a stack having a laminated structure comprising one or more cells, a separator installed between each cell so that a plurality of cells can be stacked, and a sealant arranged between the cells and the separator to maintain gas tightness. A heating coil wound multiple times around the stack without coming into contact with the outside thereof so as to generate an induced current; A high frequency generator that supplies high frequency current to the heating coil to heat the stack with heat generated by the induced current to induce bonding of the sealing material; and A high frequency controller connected to the high frequency generator to control the frequency range of the induced current so as to heat the sealant to a temperature at which heat fusion is possible; A pretreatment device for a flat fuel cell stack using high-frequency induction heating including a .

2. In claim 1, A preprocessing device for a flat fuel cell stack using high-frequency induction heating, characterized in that it further includes a heating case made of a metallic material that is heated by an induced current generated from the heating coil on the outside of the stack.

3. In claim 2, A preprocessing device for a flat fuel cell stack using high-frequency induction heating, characterized in that the heating case has a square column shape to match the shape of the stack or a cylindrical shape corresponding to the shape of the coil.

4. In claim 3, A preprocessing device for a flat fuel cell stack using high-frequency induction heating, characterized in that the inner surface of the above heating case is formed as a reflector to ensure temperature uniformity in the stack using radiant heat.

5. In claim 1, The above heating coil is configured to locally heat the stack so that a heating zone is formed in a portion of the stack, A pretreatment device for a flat-plate fuel cell stack using high-frequency induction heating, characterized in that an upper transport section is further installed to provide driving force to transport the heating coil or stack in the height direction.

6. In claim 5, The above-mentioned Shanghai conveyance changes the moving speed depending on the characteristics of the sealant or the temperature range to be heated in the sealant. A preprocessing device for a flat-plate fuel cell stack using high-frequency induction heating, characterized in that a separate speed control unit for controlling the transport speed of the upper and lower transport units is further provided.

7. In claim 1, The above heating coil is composed of a plurality of coils divided into at least two parts in the height direction of the stack, A high frequency generator that supplies high frequency current to each coil and a high frequency controller that is connected to the high frequency generator and controls the frequency range of the induced current are separately connected. A pretreatment device for a flat fuel cell stack using high-frequency induction heating, characterized by applying different heating temperature conditions to each coil as needed.

8. In claim 1 or claim 7, A pretreatment device for a flat fuel cell stack using high-frequency induction heating, characterized in that the high-frequency controller controls the frequency range of the induced current in stages so as to raise the temperature to a first temperature at which a binder component included in the sealant is removed, or to raise the temperature to a second temperature at which the sealant is softened and capable of thermal fusion.

9. In claim 1, A preprocessing device for a flat fuel cell stack using high-frequency induction heating, characterized in that the heating coil is wound in a size and shape corresponding to the external shape of the stack in a 'ㅁ' shape on a flat surface and is installed at a predetermined distance from the stack.

10. A method for pretreating a stack using a pretreating device of a flat fuel cell stack according to claims 1 to 9, (a) a step of positioning the stack inside a heating coil where a pretreatment process is to be performed; (b) a step of removing a binder component included in a sealant by supplying an alternating current to the heating coil from a high-frequency generator supplying a high-frequency current and raising the temperature to a first temperature by a magnetic field generated in the heating coil; (c) a step of supplying an alternating current to the heating coil from the high-frequency generator to further increase the temperature by the magnetic field generated in the heating coil, thereby inductively heating the sealant to a second temperature at which the sealant is softened and capable of heat fusion; and (d) a step of forming a complete sealing structure in which the sealing material is heat-fused between the cell and the separator to maintain gas tightness; A method for pretreatment of a flat fuel cell stack using high-frequency induction heating, characterized by including a.

11. In claim 10, The above first temperature has a temperature range of 200 to 400°C capable of removing the binder component contained in the sealant, A method for pretreatment of a flat fuel cell stack using high-frequency induction heating, characterized in that the second temperature has a temperature range of 600 to 800°C at which the sealant is softened and capable of thermal fusion.

12. In claim 10, The above heating coil is configured to locally heat the stack so that a heating zone is formed in a portion of the stack, A pretreatment method for a flat fuel cell stack using high-frequency induction heating, characterized in that the stack is locally sealed while the heating coil is transported by a vertical transport unit that transports the heating coil in the height direction of the stack.

13. In claim 10, The above heating coil is composed of a plurality of coils divided into at least two parts in the height direction of the stack, A high frequency generator that supplies high frequency current to each coil and a high frequency controller that is connected to the high frequency generator and controls the frequency range of the induced current are separately connected. A pretreatment method for a flat-plate fuel cell stack using high-frequency induction heating, characterized in that each coil sequentially performs steps (b) and (c) to be sealed by applying different heating temperature conditions to each coil as needed.

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