Method and apparatus for inspecting planar SOFC cell

Abstract

The present invention relates to a method and an apparatus for inspecting a planar SOFC cell, wherein pinholes, if present in an electrolyte membrane of the SOFC cell, can be measured using plasma breakdown to determine whether the pinholes are present and the location of the pinholes, external factors such as temperature changes do not have any effect, thus making pressure stabilization time unnecessary, and it does not take much time to form a vacuum since the volume requiring a vacuum is small, which has the advantage of enabling quicker inspections than a pressure change method.

Description

Inspection method and device for flat SOFC cells

[0001] The present invention relates to a method and device for inspecting a flat SOFC cell, and more particularly, to a method and device for inspecting a flat SOFC cell that can measure the presence of a pinhole in an electrolyte membrane of an SOFC cell using a plasma insulation breakdown phenomenon to determine the presence and location of a pinhole.

[0002] A fuel cell is a power generator that generates water and electricity through an electrochemical reaction between hydrogen (fuel) and oxygen. Fuel cells can be cathode, anode, and electrolyte membrane. The name and operating temperature of each fuel cell are determined by the electrolyte material.

[0003] Among them, the solid oxide fuel cell (SOFC) is one in which oxygen from the air electrode passes to the fuel electrode in the form of ions through a solid electrolyte membrane, and the flat-plate SOFC cell is composed of a multilayer structure of an anode, electrolyte membrane, and cathode.

[0004] The anode and cathode have a porous structure because reaction gases such as fuel and air must penetrate them.

[0005] On the other hand, in the case of the electrolyte membrane, it must be manufactured with a dense structure that does not allow gases to pass through in order to prevent the crossover phenomenon where fuel and air meet, and the electrolyte material of the fuel cell must be composed of a material with high ionic conductivity and low electrical conductivity.

[0006] Therefore, when looking at the entire SOFC cell, it can be said to be a structure in which gases and electrons do not pass. However, if a pinhole is created in the electrolyte membrane due to a problem in the manufacturing process, as mentioned above, a crossover phenomenon occurs in which fuel and air directly meet, which causes a direct reaction between air and fuel, leading to damage to the cell and the fuel cell stack, which is a stacked structure of multiple cells, making normal operation impossible.

[0007] Therefore, it is very important to determine whether there is a defect (pinhole) in the electrolyte membrane after manufacturing the SOFC cell from the perspective of ensuring cell quality.

[0008] As a conventional method for determining the presence of a pinhole in an electrolyte membrane, as shown in Fig. 1, there is a method of filling (or vacuuming) gas to generate a pressure difference using a passage (hole) (12) in the center (P1, P2) of a pressure plate (10) in the cathode (2) and anode (4) of the cell, and measuring the change in this pressure difference after a certain period of time.

[0009] In this case, an inspection device can be configured using a sealing jig (20) or the like to prevent gas leakage other than the pinhole of the electrolyte membrane (6).

[0010] In the inspection device of Fig. 1, a spacer (30) installed in a space due to the cell height, the pressing plate (10) and the sealing jig (20) form a sealing structure when a certain level of surface pressure is applied, thereby blocking gas leakage through the cell side.

[0011] A number of holes (22) are formed at regular intervals in the center of the above sealing jig (20), so that gas transmitted through the passage (12) of the pressing plate (10) can move to the electrodes (Anode, Cathode) of the cell.

[0012] However, this conventional method has limitations in that even if there is a pinhole in the electrolyte membrane (6), it is difficult to measure the pressure change because it is very small, and even if it is possible to determine the presence of a pinhole in the electrolyte membrane (6), it is impossible to determine the location and number of the pinholes.

[0013] In addition, the pressure stabilization time is required at the P1 and P2 locations, which are passages (12) of the compression plate (10) through which gas is injected or vacuum is created, as they are sensitive to external factors such as temperature changes (pressure changes according to temperature), and the pressure changes must be measured after a certain period of time, so there is a disadvantage in that the measurement time is long.

[0014] The present invention has been devised to solve the above problems, and the purpose of the present invention is to provide a method and device for inspecting a flat-plate SOFC cell, which can determine whether a pinhole exists by measuring the occurrence of insulation breakdown at a corresponding voltage when a pinhole exists in the electrolyte membrane of the SOFC cell using the plasma insulation breakdown phenomenon.

[0015] In addition, the purpose is to provide a method and device for inspecting a flat SOFC cell that can estimate not only the presence of a pinhole in an electrolyte membrane but also the location where a leak occurs.

[0016] In addition, the purpose is to provide a method and device for inspecting a flat-plate SOFC cell that is not affected by external factors such as temperature changes, so that pressure stabilization time is unnecessary and measurement time can be shortened.

[0017] In order to achieve the above object of the present invention, the present invention provides an inspection device for determining the presence of a pinhole in an electrolyte membrane in a planar SOFC cell composed of an anode, a cathode, and an electrolyte membrane, the inspection device comprising: a compression plate installed to apply a certain level of surface pressure to the upper and lower portions of the cell, and having a passage formed for injecting plasma processing gas to determine the presence of a pinhole in the electrolyte membrane; a sealing jig installed on both sides of the cell to form a sealing structure when surface pressure is applied to the compression plate so that no gas leakage occurs except for the pinhole of the electrolyte membrane; a spacer installed in a space on both sides of the cell so as to form a sealing structure together with the sealing jig when surface pressure is applied to the compression plate; a plasma processing space that forms a predetermined space in which a cell is accommodated between the sealing jig and has an airtight structure capable of maintaining a predetermined vacuum level; an upper electrode installed on the cathode side within the processing space; and an upper electrode and the upper electrode being mutually connected. An inspection device for a flat SOFC cell is provided, characterized in that it comprises a lower electrode installed on the anode side facing each other, an RF power source for supplying power to generate plasma between the upper electrode and the lower electrode, and a sensor for determining the presence of a pinhole by detecting an insulation breakdown at a corresponding location when a pinhole exists in the electrolyte membrane of the cell.

[0018] The upper electrode and the lower electrode are characterized in that they are configured in a form that is divided into multiple parts.

[0019] In addition, the upper electrode and the lower electrode of the present invention are installed in an array manner, and the sensor is installed on each of the lower electrodes to check whether insulation breakdown occurs at each location, thereby making it possible to estimate at which location in the cell a pinhole occurred.

[0020] Meanwhile, the plasma treatment gas includes an inert gas, and the inert gas is characterized by being at least one of argon, helium, neon, or a mixed gas thereof.

[0021] When an inert gas is used as the above plasma treatment gas, evaluation is possible at a low applied voltage, thereby preventing unintended cell damage due to high voltage.

[0022] Meanwhile, the spacer is installed so as to be in contact with the electrolyte membrane of the cell and the side of the anode, and the sealing jig is installed on the upper and lower surfaces of the spacer, wherein the sealing jig installed on the upper surface of the spacer forms an upper plasma processing space in which the cathode and the upper electrode are accommodated, and the sealing jig installed on the lower surface of the spacer forms a lower plasma processing space in which the lower electrode and the sensor are accommodated.

[0023] In addition, in order to achieve the above object of the present invention, the present invention provides a flat-plate SOFC cell, including the steps of: positioning a flat-plate SOFC cell in a plasma processing space having an airtight structure capable of maintaining a predetermined vacuum level; applying a predetermined level of surface pressure by pressing press plates installed above and below the cell; forming a sealing structure through sealing jigs and spacers installed on both sides of the cell when the surface pressure is applied to the press plates, thereby sealing so that no gas leakage occurs except for pinholes in the electrolyte membrane of the cell; injecting plasma processing gas into a passage formed in the press plate to determine whether a pinhole exists in the electrolyte membrane; supplying RF power to the upper electrode installed on the cathode side of the cell and the lower electrode installed on the anode side so that plasma is generated between the upper electrode and the lower electrode; and, if a pinhole exists in the electrolyte membrane of the cell, a step of causing insulation breakdown at the corresponding location and measuring this by a sensor to determine whether a pinhole exists. Inspection methods are provided.

[0024] In this case, the upper electrode and the lower electrode are divided into multiple pieces and installed in an array manner, and the sensor is installed on each of the lower electrodes to check whether insulation breakdown occurs at each location, thereby making it possible to estimate at which location in the cell a pinhole occurred.

[0025] In addition, since an inert gas is used as the plasma treatment gas and evaluation is possible at a low applied voltage, unintended cell damage due to high voltage can be prevented.

[0026] In addition, the spacer is installed so as to contact the electrolyte membrane of the cell and the side of the anode, and the sealing jig is installed on the upper and lower surfaces of the spacer, wherein the sealing jig installed on the upper surface of the spacer forms an upper plasma processing space in which the cathode and the upper electrode are accommodated, and the sealing jig installed on the lower surface of the spacer forms a lower plasma processing space in which the lower electrode and the sensor are accommodated, so that the time required for vacuum formation in the upper plasma processing space and the lower plasma processing space is short, enabling rapid inspection.

[0027] According to the present invention as discussed above, when a pinhole exists in the electrolyte membrane of an SOFC cell by utilizing the plasma insulation breakdown phenomenon, insulation breakdown occurs at a corresponding voltage, and by measuring this, there is an effect of being able to determine whether or not there is a pinhole.

[0028] Additionally, it is possible to determine not only whether there are pinholes in the electrolyte membrane but also where the leakage occurs.

[0029] In addition, it is not affected by external factors such as temperature changes, so there is no need for pressure stabilization time, and since the volume requiring vacuum is small, it does not take a long time to form a vacuum, so it has the advantage of allowing for quick inspection compared to the pressure change method.

[0030] In addition, since it is a non-contact inspection method that does not come into contact with the surfaces of the anode and cathode of the SOFC cell, it has the advantage of not damaging the cell during inspection, and since evaluation is possible at a low applied voltage when an inert gas is used, unintended cell damage due to high voltage can be prevented.

[0031] Figure 1 is a cross-sectional view showing an inspection device for a conventional flat-panel SOFC cell, which determines whether a pinhole exists in an electrolyte membrane.

[0032] Figure 2 is a cross-sectional view illustrating an inspection device for a flat SOFC cell according to the present invention.

[0033] FIG. 3 is a plan view showing (a) the cathode and the upper electrode in the inspection device of the flat SOFC cell shown in FIG. 2, and (b) a bottom view showing the anode and the lower electrode.

[0034] Figure 4 is a Paschen curve graph showing how the breakdown voltage varies depending on the type of gas, the distance between electrodes (d), and the pressure of the gas (p, vacuum).

[0035] Figure 5 is a flowchart showing an inspection method of a flat SOFC cell according to the present invention.

[0036] 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.

[0037] FIG. 2 is a cross-sectional view illustrating an inspection device for a flat SOFC cell according to the present invention, and FIG. 3 is a plan view illustrating (a) a cathode and an upper electrode, and (b) a bottom view illustrating an anode and a lower electrode in the inspection device for a flat SOFC cell illustrated in FIG. 2.

[0038] The present invention is an inspection device for determining whether a pinhole exists in an electrolyte membrane (6) in a flat-type SOFC cell composed of an anode (4), a cathode (2), and an electrolyte membrane (6), and has a configuration that can measure the presence of a pinhole in the electrolyte membrane of the SOFC cell by using a plasma insulation breakdown phenomenon, and determine whether there is a pinhole and its location.

[0039] Specifically, the inspection device of the flat SOFC cell of the present invention includes a pressing plate (110) installed to apply a certain level of surface pressure to the upper and lower portions of the cell, a sealing jig (120) installed on both sides of the cell to form a sealing structure when the surface pressure is applied to the pressing plate (110), and a spacer (130) installed in a space on both sides of the cell to form a sealing structure together with the sealing jig (120) when the surface pressure is applied to the pressing plate (110).

[0040] The above pressing plate (110) has a passage (112) formed in the center for injecting plasma processing gas, and the sealing jig (120) is installed on both sides of the cell to form a sealing structure when surface pressure is applied to the pressing plate (110) so that no gas leakage occurs except for the pinhole of the electrolyte membrane (6).

[0041] A spacer (130) is installed in the space on both sides of the above cell. The spacer (130) is installed to fill the space due to the height of the cell so that a sealing structure can be formed together with the sealing jig (120) when surface pressure is applied to the pressing plate (110).

[0042] The above spacer (130) is installed so as to be in contact with the side of the electrolyte membrane (6) and the anode (4) of the cell. Typically, as shown in FIGS. 2 and 3, the area of ​​the electrolyte membrane (6) and the anode (4) of the cell are formed to be the same, and the cathode (2) has a smaller size than the electrolyte membrane (6).

[0043] In the present invention, the spacer (130) is installed so as to be in contact with the electrolyte membrane (6) of the cell and the side surface of the anode (4), and the sealing jig (120) installed on the upper and lower surfaces of the spacer (130) is installed so that a predetermined space (122) for plasma generation is formed therebetween.

[0044] Specifically, the sealing jig (120) installed on the upper surface of the spacer (130) is installed to form an upper plasma processing space (122) in which the cathode (2) and the upper electrode (210) are accommodated, and the sealing jig (120) installed on the lower surface of the spacer (130) is installed to form a lower plasma processing space in which the lower electrode (220) and the sensor (240) are accommodated.

[0045] The plasma treatment space formed between the sealing jigs (120) is installed so that the pressing plate (110), spacer (130), and sealing jig (120) have a sealed structure that can maintain a predetermined vacuum level, and thus form a sealed structure when a certain level of surface pressure is applied, thereby blocking gas leakage through the cell side.

[0046] This plasma treatment space (122) is connected to a passage (112) for injecting the plasma treatment gas.

[0047] In the above processing space (122), an upper electrode (210) is installed on the cathode (2) side, a lower electrode (220) is installed on the anode (4) side facing the upper electrode (210), and an RF power source (230) is installed to supply power so that plasma is generated between the upper electrode (210) and the lower electrode (220).

[0048] A sensor (240) capable of determining the presence or absence of a pinhole is installed in the lower electrode (220).

[0049] The above sensor (240) can determine whether a pinhole exists by determining whether an insulation breakdown occurs at a corresponding location when a pinhole exists in the electrolyte membrane (6) of the cell. When the plasma treatment gas is injected through the passage (112), in the case of a cell without a pinhole, insulation breakdown does not occur when voltage is applied because it is an insulator, but when a pinhole exists in the electrolyte membrane (6), insulation breakdown occurs at the corresponding voltage, and the sensor (240) can detect this, thereby determining whether a pinhole exists.

[0050] In the present invention, the plasma treatment gas is used to determine whether a pinhole exists in the electrolyte membrane (6), and may include an inert gas.

[0051] The above inert gas may be composed of at least one of argon, helium, neon, or a mixture thereof. When an inert gas is used as the plasma treatment gas, evaluation can be performed at a low applied voltage, thereby preventing unintended cell damage due to high voltage.

[0052] In addition, the upper electrode (210) and the lower electrode (220) are characterized in that they are configured in a form in which they are separated into multiple pieces.

[0053] That is, as seen in FIGS. 2 and 3, the upper electrode (210) and the lower electrode (220) of the present invention are installed in an array manner, and the sensor (240) is installed on each of the lower electrodes (220) to check whether insulation breakdown occurs at each location, thereby making it possible to estimate at which location in the cell a pinhole occurred.

[0054] The inspection method using the inspection device of the flat SOFC cell of the present invention having such a configuration is as follows.

[0055] FIG. 5 is a flowchart showing a method for inspecting a flat SOFC cell according to the present invention, wherein a flat SOFC cell composed of an anode, a cathode, and an electrolyte membrane is positioned in a plasma processing space (122) of a sealed structure capable of maintaining a predetermined vacuum level (S110).

[0056] As described above, the plasma treatment space (122) is a predetermined space (122) for plasma generation between the sealing jig (120) installed on the upper and lower surfaces of the spacer (130), and the spacer (130) is installed to contact the side surface of the electrolyte membrane (6) and the anode (4) of the cell, the cathode (2) and the upper electrode (210) are accommodated in the upper plasma treatment space (122), and the lower electrode (220) and the sensor (240) are accommodated in the lower plasma treatment space.

[0057] A pressure plate (110) installed above and below the above cell is pressed to apply a certain level of surface pressure (S120).

[0058] When pressure is applied to the above pressing plate (110), a sealing structure is formed through the sealing jig (120) and spacer (130) installed on both sides of the cell, thereby sealing so that no gas leakage occurs except for the pinhole of the electrolyte membrane of the cell (S130).

[0059] Afterwards, in order to determine whether a pinhole exists in the electrolyte membrane (6), plasma treatment gas is injected into the passage (112) formed in the pressing plate (110) (S140).

[0060] Here, an inert gas is used as the plasma treatment gas, and may be composed of at least one of argon, helium, neon, or a mixed gas thereof.

[0061] Thereafter, RF power is supplied to the upper electrode (210) installed on the cathode (2) side of the cell and the lower electrode (220) installed on the anode (4) side so that plasma is generated between the upper electrode (210) and the lower electrode (220) (S150).

[0062] If a pinhole exists in the electrolyte membrane (6) of the above cell, insulation breakdown occurs at the corresponding voltage, and the sensor (240) measures this to determine whether a pinhole exists (S160).

[0063] That is, when the plasma treatment gas is injected through the passage (112) and RF power is supplied to the upper electrode (210) and the lower electrode (220), in the case of a cell without a pinhole, insulation breakdown does not occur when voltage is applied because it is an insulator, but when a pinhole exists in the electrolyte membrane (6), insulation breakdown occurs at the corresponding voltage, and this can be detected by the sensor (240), so that the presence or absence of a pinhole can be determined.

[0064] In this case, the upper electrode (210) and the lower electrode (220) are configured in a divided form by being separated into multiple pieces and installed in an array manner, and the sensor (240) is installed on each of the lower electrodes (220) to check whether insulation breakdown occurs at each location, thereby making it possible to estimate at which location in the cell a pinhole occurred.

[0065] Fig. 4 is a Paschen curve graph showing how the breakdown voltage varies depending on the type of gas, the distance between electrodes (d), and the pressure of the gas (p, vacuum degree). When a strong electric field is applied to a neutral gas, the gas, which is an insulator, becomes a plasma state above a certain voltage and has the properties of a conductor. As seen in the Paschen curve of Fig. 4, this breakdown voltage varies depending on the type of gas, the distance between electrodes (d), and the pressure of the gas (p, vacuum degree), and inert gases such as Ar (E) and Ne (F) have relatively low breakdown voltages compared to air (A).

[0066] As can be seen in FIG. 4, the present invention can be evaluated at a low applied voltage when using an inert gas, thereby preventing unintended cell damage due to high voltage.

[0067] In addition, since the volume required for vacuum in the anode (4) and cathode (2) of the SOFC cell is small, it does not take much time to form a vacuum, so there is an advantage in that rapid inspection is possible compared to the pressure change method.

[0068] In addition, the inspection method of the present invention is a non-contact inspection method that does not come into contact with the anode and cathode surfaces of the SOFC cell, so it has the advantage of not causing damage to the cell during inspection.

[0069] 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. An inspection device for determining the presence of pinholes in an electrolyte membrane in a flat SOFC cell composed of an anode, cathode, and electrolyte membrane. A pressure plate installed to apply a certain level of surface pressure to the upper and lower portions of the above cell, and having a passage formed therein for injecting plasma treatment gas to determine whether a pinhole exists in the above electrolyte membrane; A sealing jig installed on both sides of the cell to form a sealing structure when surface pressure is applied to the pressing plate so that no gas leakage occurs other than the pinhole of the electrolyte membrane; A spacer installed in the space on both sides of the cell so as to form a sealing structure together with the sealing jig when surface pressure is applied to the pressing plate; A plasma treatment space having a sealed structure that forms a predetermined space in which cells are accommodated between the above sealing jigs and can maintain a predetermined vacuum level; An upper electrode installed on the cathode side within the above processing space; A lower electrode installed on the anode side, facing the upper electrode; An RF power source that supplies power to generate plasma between the upper electrode and the lower electrode; and A sensor capable of determining the presence of a pinhole by detecting an insulation breakdown at a corresponding location when a pinhole exists in the electrolyte membrane of the above cell; An inspection device for a flat SOFC cell, characterized in that it comprises a structure including:

2. In claim 1, An inspection device for a flat SOFC cell, characterized in that the upper electrode and the lower electrode are configured in a form in which they are separated into a plurality of pieces.

3. In claim 2, The upper and lower electrodes are installed in an array manner. An inspection device for a flat-plate SOFC cell, characterized in that the sensor is installed on each of the lower electrodes to check whether insulation breakdown occurs at each location, thereby enabling an estimate of where a pinhole occurred in the cell.

4. In claim 1, An inspection device for a flat-plate SOFC cell, characterized in that the plasma treatment gas contains an inert gas, and the inert gas is at least one of argon, helium, neon, or a mixed gas thereof.

5. In claim 4, An inspection device for a flat-plate SOFC cell characterized in that when an inert gas is used as the plasma treatment gas, evaluation is possible at a low applied voltage, thereby preventing unintended cell damage due to high voltage.

6. In claim 1, The above spacer is installed so as to contact the electrolyte membrane of the cell and the side of the anode, The sealing jig is installed on the upper and lower surfaces of the above spacer, A sealing jig installed on the upper surface of the above spacer forms an upper plasma treatment space in which the cathode and upper electrode are accommodated, An inspection device for a flat-plate SOFC cell, characterized in that a sealing jig installed on the lower surface of the spacer forms a lower plasma treatment space in which the lower electrode and sensor are accommodated.

7. A step of positioning a flat SOFC cell in a plasma treatment space having a sealed structure capable of maintaining a predetermined vacuum level; A step of applying a certain level of surface pressure by pressing the pressing plates installed above and below the above cell; A step of forming a sealing structure through a sealing jig and spacers installed on both sides of the cell when surface pressure is applied to the pressing plate, thereby sealing so that no gas leakage occurs except for pinholes in the electrolyte membrane of the cell; A step of injecting plasma treatment gas into a passage formed in the pressing plate to determine whether a pinhole exists in the electrolyte membrane; A step of supplying RF power to the upper electrode and the lower electrode so that plasma is generated between the upper electrode installed on the cathode side of the cell and the lower electrode installed on the anode side; and When a pinhole exists in the electrolyte membrane of the above cell, an insulation breakdown occurs at that location, and a sensor measures this to determine whether a pinhole exists; A method for inspecting a flat SOFC cell including a .

8. In claim 7, The upper and lower electrodes are divided into multiple pieces and installed in an array format. A method for inspecting a flat SOFC cell, characterized in that the sensor is installed on each of the lower electrodes to check whether insulation breakdown occurs at each location, thereby enabling an estimate of the location of the cell where a pinhole occurred.

9. In claim 7, A method for inspecting a flat-plate SOFC cell, characterized in that it uses an inert gas as the plasma treatment gas and enables evaluation at a low applied voltage, thereby preventing unintended cell damage due to high voltage.

10. In claim 7, The above spacer is installed so as to contact the electrolyte membrane of the cell and the side of the anode, The sealing jig is installed on the upper and lower surfaces of the above spacer, A sealing jig installed on the upper surface of the above spacer forms an upper plasma treatment space in which the cathode and upper electrode are accommodated, The sealing jig installed on the lower surface of the above spacer forms a lower plasma treatment space in which the lower electrode and sensor are accommodated. An inspection method for a flat-plate SOFC cell, characterized in that a short time is required to form a vacuum in the upper plasma treatment space and the lower plasma treatment space, enabling rapid inspection.

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