JP6351360B2 - Inspection device and inspection method for solid oxide fuel cell - Google Patents

Description

  The present invention relates to an inspection apparatus and an inspection method for a solid oxide fuel cell.

A solid oxide fuel cell generates electricity using oxygen in the air and hydrogen or carbon monoxide made from city gas. For example, as known from Patent Document 1, a plurality of single oxide fuel cells are used. The cell is electrically connected via an interconnector, and further includes a cell structure having a manifold at a lower portion thereof. In this single cell, a fuel electrode, a solid electrolyte, and an oxygen electrode are supported by a support. Fuel gas is supplied from the manifold to the cell, and oxygen-containing gas is separately supplied to the cell. As shown above, the structural members constituting the cell structure include structural members, interconnectors, manifolds, etc., which constitute a single cell. These structural members are obtained by firing at high heat in the assembly process. Be joined.
For example, as disclosed in Patent Document 2, the space between the manifold body made of a heat-resistant metal and the cell is gas-sealed with glass ceramics, and in order to improve the manufacturing quality, the shape and material Ingenuity has been proposed. However, since it is returned to room temperature (room temperature) after being exposed to a high temperature exceeding several hundred degrees Celsius during its manufacturing process, it is inevitable that residual stress is generated inside the solid oxide fuel cell, and this residual stress is released. Cracks occur when The solid oxide fuel cell has a high temperature of 800 ° C. when driven, and is returned to room temperature when the driving is stopped. In other words, when this solid oxide fuel cell actually starts to be used, the temperature change between high temperature and room temperature will repeatedly act. In a solid oxide fuel cell with poor production quality, This causes a problem that an unexpected amount of cracks occurs and the amount of gas leakage increases.

JP 2004-234970 A JP 2013-182679 A

  In view of the above circumstances, an inspection technique capable of evaluating the manufacturing quality of a solid oxide fuel cell is required.

The first characteristic configuration of the inspection apparatus for a solid oxide fuel cell according to the present invention is:
An AE sensor mounted on the solid oxide fuel cell;
Under conditions that the temperature load is applied to the solid oxide fuel cell, and the AE signal acquisition unit that acquires a signal from the AE sensor,
An AE evaluation unit that evaluates crack generation in the solid oxide fuel cell from the AE signal ,
The temperature load is
Including a first temperature change due to a temperature drop from a high temperature to a room temperature during manufacture of the solid oxide fuel cell;
The AE signal acquisition unit acquires a signal from the AE sensor and the AE evaluation unit evaluates the occurrence of the crack under a situation where a temperature load due to the first temperature change is given .

  In a solid oxide fuel cell manufactured by a manufacturing process at a high temperature, a tissue strain is generated due to a temperature change (temperature load) when the temperature is lowered to room temperature (normal temperature), and micro cracks are generated. In addition, the strain creates stress and remains in the product as residual stress. For this reason, cracks are generated by forcibly giving a temperature change to the product. In the present invention, an AE sensor detects an AE (acoustic emission) wave that is a shock wave emitted when a crack occurs in the solid oxide fuel due to such a temperature change. At the time of detection, in order to receive the AE wave that has propagated through the constituent member of the solid oxide fuel, an AE sensor that receives the AE wave is attached to an appropriate portion of the propagation path. The AE signal detected by the AE sensor and converted into an electrical signal is used in the AE evaluation unit to evaluate the amount of cracks generated in the solid oxide fuel. Since the amount of crack generation (hereinafter simply referred to as crack amount) is related to the amount of leakage of gas flowing through the solid oxide fuel, that is, the amount of gas leakage, the amount of gas leakage is evaluated by evaluating this AE signal. Can be estimated. For this reason, it is possible to omit the time-consuming gas leak inspection that is actually performed by flowing gas through the product, or to make such a gas leak inspection only for products that are considered more problematic. be able to.

In order to solve the above problems, the first characteristic configuration of the inspection method for the solid oxide fuel cell according to the present invention is:
Attaching an AE sensor to the solid oxide fuel cell;
Under conditions that the temperature load is applied to the solid oxide fuel cell, and the AE signal acquisition step of acquiring a signal from the AE sensor,
An AE evaluation step for evaluating crack generation in the solid oxide fuel cell from the AE signal ,
The temperature load is
Including a first temperature change due to a temperature drop from a high temperature to a room temperature during manufacture of the solid oxide fuel cell;
In a situation where a temperature load due to the first temperature change is applied, the AE signal acquisition step acquires a signal from the AE sensor, and the AE evaluation step evaluates the occurrence of the crack. As the operational effects obtained by this inspection method, what has been described in the above-described inspection apparatus can be used as it is.

A second characteristic configuration of the inspection apparatus having the first characteristic configuration is that the temperature load further includes a second temperature change between a driving temperature of the solid oxide fuel cell and a room temperature. . AE released when a crack is generated when a solid oxide fuel cell is exposed to a temperature change from a high temperature to room temperature or a temperature change from room temperature to high temperature between the driving temperature and room temperature. By detecting and evaluating the waves, a crack inspection at the time of occurrence, and consequently a leak inspection is performed. The driving temperature of the solid oxide fuel cell during power generation becomes high heat exceeding several hundred degrees Celsius, and is returned to room temperature when the driving is stopped. In other words, in actual use, the solid oxide fuel cell is always exposed to a temperature change between the driving temperature and the room temperature. Therefore, it is meaningful to perform an inspection at this temperature load before shipping. . Naturally, this technique can also be implemented as an inspection technique.

  A third characteristic configuration of the inspection apparatus having the first or second characteristic configuration is that AE inspection is performed a plurality of times while applying a temperature load. The amount of cracks that accompanies the release of residual stress inherent in a solid oxide fuel cell tends to decrease as the applied temperature load, that is, the number of temperature changes, increases. By performing it a plurality of times, a highly reliable product can be shipped. Naturally, this technique can also be implemented as an inspection technique.

The fourth feature configuration of the inspection apparatus having the first to third feature configurations is the AE signal evaluation method performed by the AE evaluation unit, in which the occurrence of cracks is based on the integration amount of the acquired AE signal. Be evaluated. Since the AE wave is a vibration wave, the AE signal can be processed as a waveform signal. Therefore, the time amplitude value of the AE signal can be integrated through a relatively simple circuit configuration or software processing. The occurrence of cracks is evaluated based on the integration of the time amplitude value of the AE signal, that is, the integration amount of the AE signal. Since the release of energy due to cracks generated in the material structure generates AE waves, it is highly possible that the energy of the AE waves, that is, the time integral value of the AE waves, represents the characteristics of the cracks. It can be estimated effectively. In addition, the occurrence of a crack leads to a gas leak through the crack. From this, it becomes possible to derive the gas leak amount from the integral amount of the AE signal. Naturally, this technique can also be implemented as an inspection technique.
A fifth feature configuration of the inspection apparatus having the fourth feature configuration includes an integral amount-gas leak amount table for deriving a gas leak amount resulting from the occurrence of the crack from the integral amount of the AE signal. The quality evaluation of the solid oxide fuel cell is performed based on the gas leak amount.
By calculating the correlation between the integral amount of the AE signal and the gas leak amount experimentally and statistically in advance and creating an integral amount-gas leak amount table for deriving the gas leak amount based on the calculation result, the AE Conveniently, it is possible to estimate the amount of gas leak only by obtaining the integral amount of the signal. Naturally, this technique can also be implemented as an inspection technique.

The sixth characteristic configuration of the inspection apparatus described so far is that the AE sensor is attached to a metal piping member that supplies fuel gas and oxidant gas to the solid oxide fuel cell main body. .
Since the metal piping member for supplying the fuel gas and the oxidant gas has a surface temperature lower than the temperature of the solid oxide fuel cell main body, it is considered that the mounting position of the AE sensor as the metal piping member is a high temperature. There are advantages for AE sensors with limitations. Of course, it may be attached to another member having a surface temperature lower than the temperature of the solid oxide fuel cell main body by having a heat dissipation function.
The AE sensor generally includes a piezoelectric element that converts vibration into an electrical signal. Since the vibration characteristics such as the frequency of the AE signal vary depending on the material and the type of the crack, the vibration characteristics that are desired to be detected, especially the piezoelectric element that has good reception sensitivity of the frequency that is desired to be detected, or the piezoelectric element that detects the broadband frequency is required. Choose it. Piezoelectric elements include those using a flexible polymeric piezoelectric material and those using a piezoelectric ceramic such as a barium titanate type. In consideration of the temperature of the mounting surface, the piezoelectric ceramic is preferable. An acoustic coupling agent is applied between the mounting surface and the receiving surface (piezoelectric element surface) of the AE sensor. By using a heat-resistant acoustic coupling agent, a high-temperature mounting surface can be dealt with. Furthermore, when the temperature of the mounting surface exceeds several hundred degrees, use of a non-contact type ultrasonic sensor using an electromagnetic ultrasonic method or non-contact type AE wave detection using a laser interferometer is also considered. Is done.

The present seventh characterizing feature of the inspection apparatus described so far, as the thermal load, further, further comprising: a sub-zero temperature of below zero 15 degrees to minus 5 degrees, the third temperature change between the room temperature, the An overcooling AE inspection step in which a signal from the AE sensor is acquired under a situation where a third temperature load is applied is further provided.
When the solid oxide fuel cell is cooled to a sub-zero temperature from 15 degrees below zero to 5 degrees below zero, the temperature change from room temperature to sub-zero temperature and the temperature increase from sub-zero temperature to room temperature are affected. . According to the knowledge of the inventor of the present application, the occurrence of cracks associated with the release of the residual stress of the solid oxide fuel cell is caused by the fact that the solid oxide fuel cell is subjected to a subzero temperature ranging from 15 degrees below zero to 5 degrees below zero and room temperature. It is speculated that it will be accelerated by exposure to temperature changes in between. For this reason, as a pre-shipment inspection, the solid oxide fuel cell is subjected to an AE inspection while performing an overcooling process to a sub-zero temperature from below 15 degrees to 5 degrees below zero. Cracks that occur over time can be grasped, and products that generate many cracks can be removed from shipment. Naturally, this technique can also be implemented as an inspection technique.

It is explanatory drawing explaining the basic principle of manufacture of the solid oxide fuel cell used as the object of this invention, and the test | inspection by this invention. It is explanatory drawing explaining another basic principle of manufacture of the solid oxide fuel cell used as the object of this invention, and the test | inspection by this invention. It is a functional block diagram showing typically one embodiment of equipment which manufactures and inspects a solid oxide fuel cell by the present invention. It is a functional block diagram showing typically another embodiment of equipment which manufactures and inspects a solid oxide fuel cell by the present invention. The solid oxide fuel cell manufactured through the heat treatment shows a guess curve for guessing the change over time in the amount of gas leak when used as a generator. (A) is a guess curve without overcooling treatment. Yes, (b) is a guess curve with overcooling treatment. It is a graph which shows the relationship between AE signal integration amount and gas leak amount for every multiple overcooling process.

Before describing the embodiment of the inspection apparatus according to the present invention in detail, the basic steps of manufacturing and inspection of a solid oxide fuel cell will be described with reference to FIG. In the solid oxide fuel cell, a plurality of single cells in which a fuel electrode, a solid electrolyte, and an oxygen electrode are supported by a support are electrically connected by an interconnector, and further, fuel gas is supplied to the lower part of each cell. These manifolds have a cell structure in which the manifolds are connected and integrated, and include a glass seal portion for sealing gas. In general, a solid oxide fuel cell has a single cell in which an air electrode is joined to one side of an electrolyte membrane and a fuel electrode is joined to the other side of the electrolyte membrane. Thus, the structure is sandwiched between a pair of electron conductive base materials (inter-cell connecting members) that exchange electrons. And it operates at an operating temperature of about 700 to 900 ° C., for example, and an electromotive force is generated between the pair of electrodes along with the movement of oxide ions through the electrolyte membrane from the air electrode side to the fuel electrode side. The electromotive force can be taken out and used outside. The inter-cell connecting member corresponds to an interconnector or a member that electrically connects cells via the interconnector. The solid oxide fuel cell exemplified here is, for example, at least a fuel electrode 11, a solid electrolyte 12, and oxygen as basic constituent members as shown in Patent Document 1 (Japanese Patent Laid-Open No. 2004-234970). It includes a plurality of cells (single cells) 10 each having an electrode 13 and a manifold 16 in which a gas flow path is formed. The cells 10 and the manifold 16 are joined together by a glass seal portion. Note that a fuel gas passage through which fuel, for example, hydrogen flows, is provided as a gas passage in the manifold 16 and from the manifold 16 to the cell 10. In the present application, in addition to the fuel gas flow path, an oxidant gas flow path for supplying an oxidant gas to the cell is also included as a gas path. However, the illustration here is omitted. These basic components are assembled by a firing process at a high temperature of 1000 ° C. That is, after each component is prepared as a pretreatment (# 01), it is heated (fired) (# 02), and the temperature is lowered to room temperature (# 03). In parallel with this manufacturing process, a manufacturing inspection using the AE technique is performed (# 04). For products that have passed this inspection, a conventional leak inspection is performed as necessary, and a final acceptable product is shipped (# 05).
The occurrence of cracks that are problematic in solid oxide fuel cells is primarily due to tissue strain in the manufacturing process. In the present invention, the occurrence of this crack is detected using an AE technique that detects an ultrasonic wave (AE wave) generated when the crack occurs. In the AE inspection here (# 04), first, the AE sensor 3 is mounted at a location where the surface temperature is relatively low and the ultrasonic propagation characteristics are good among the constituent members of the solid oxide fuel cell (# 41). ). The AE sensor detects an AE wave generated in the solid oxide fuel cell and converts it into an electrical AE signal. The acquired AE signal is subjected to signal processing such as amplification, filtering, and waveform processing (# 43), and is used for evaluation of the crack generation amount and consequently the gas leak amount (# 44). In particular, cracks are likely to occur when the room temperature is returned after heating at # 02. Therefore, the AE wave generated during the room temperature return process is detected by the AE sensor, and the obtained AE signal is processed to cause a gas leak. It is preferred to make an assessment regarding the amount.

  Instead of or in addition to the above-described AE inspection as a manufacturing inspection, an AE inspection as a post-manufacturing inspection may be performed after the manufacturing process. The process and flow in that case are shown in FIG. That is, after each component is prepared as a pretreatment (# 01), it is heated (fired) (# 02), and the temperature is lowered to room temperature (# 03). Next, product inspection using AE technology is performed (# 04). Those that pass this inspection are shipped (# 05). In the AE inspection as the post-manufacture inspection, the crack detection is performed more efficiently by exposing the solid oxide fuel cell after the manufacture to a temperature change as a temperature load. Of course, here too, a conventional leak test may be used in combination with the product test.

  The generation of cracks, which is a problem in solid oxide fuel cells, is primarily caused by the strain in the structure when the temperature is lowered from the heating (firing) step at high temperature to the room temperature during the manufacturing process. Is due to the release of residual stress due to tissue strain. Therefore, it is also preferable to evaluate the degree of occurrence of cracks when a temperature change is applied as a temperature load to the fired solid oxide fuel cell. Of course, this AE inspection may be applied as both inspection during manufacturing and inspection after manufacturing.

  Since the solid oxide fuel cell has a high temperature of about 800 ° C. when driven, when it is actually used as a generator, it undergoes a temperature change between room temperature and about 800 ° C. Therefore, the AE inspection is performed while giving the solid oxide fuel cell a temperature change between room temperature and about 800 ° C. This temperature change may be achieved by using a heating mechanism incorporated in the manufacturing apparatus as a temperature load device or by actually performing a trial run of the solid oxide fuel cell by supplying gas to the solid oxide fuel cell. You may employ | adopt the form which gives a temperature change (temperature load). At that time, the inspection apparatus incorporates a device for performing a trial operation of the solid oxide fuel cell as a temperature load apparatus. This temperature load may be given a plurality of times, and an AE inspection may be performed each time. In addition, the occurrence of cracks to be subjected to the crack inspection includes not only a joining portion such as a glass seal portion for sealing a gas but also the structure of the cell 10 itself.

  Next, a solid oxide fuel cell manufacturing facility including a solid oxide fuel cell inspection apparatus and a solid oxide fuel cell manufacturing apparatus, which is one embodiment of the present invention, will be described. FIG. 3 is a functional block diagram showing functional units particularly relevant to the present invention in such a manufacturing facility. Since the manufacturing apparatus of this solid oxide fuel cell is known per se, only the manufacturing controller 5 and the heating mechanism 60 are schematically shown here. In this embodiment, the inspection apparatus includes an AE sensor 3, an inspection controller 4 that performs signal processing and evaluation of the AE wave detected by the AE sensor 3, and a temporary load for applying a temperature load to the solid oxide fuel cell. And a temperature load controller 4a as a temperature load device for trial use of the solid oxide fuel cell. Note that the temperature load controller 4a is omitted when the temperature load applied to the solid oxide fuel cell is only the temperature change during the temperature lowering process from the firing temperature during the production of the solid oxide fuel cell to room temperature. The Further, a temperature load may be applied to the solid oxide fuel cell using a heating mechanism of the manufacturing apparatus. In this case, the manufacturing controller 50 also serves as the temperature load controller 4a.

  As for the solid oxide fuel cell, only the cell 10 including the fuel electrode 11, the solid electrolyte 12, and the oxygen electrode 13 and the manifold 16 in which the gas flow path 15 is formed are schematically shown. (In FIG. 3, the gas flow path 15 representatively shows a fuel gas flow path).

  In the production of the solid oxide fuel cell, each component of the solid oxide fuel cell is prepared before firing using the heating mechanism 60, and a sealing agent is applied to the joint surface. After the heat treatment is completed, the solid oxide fuel cell that has been fired and assembled is cooled to room temperature. If the surface temperature of the gas piping member 17 is lowered to such an extent that the AE sensor 3 made of a piezoelectric element is not damaged during the temperature lowering process (decreasing temperature change), the gas piping connected to the manifold 16 of the solid oxide fuel cell. Mounted on the member 17. Of course, when the AE sensor 3 using the piezoelectric element that can withstand the high temperature of the solid oxide fuel cell during the heat treatment or the non-contact type AE sensor 3 is used, The AE sensor 3 can be attached in stages. The gas piping member 17 is made of a metal material, and ultrasonic waves propagate efficiently. Therefore, when a micro crack is generated inside the solid oxide fuel cell, the AE wave generated due to the micro crack reaches the AE sensor 3 through the gas piping member 17. The AE wave is converted into an AE signal (electric signal) by the AE sensor 3 and input to the AE signal acquisition unit 30 of the inspection controller 4. The AE signal acquisition unit 30 is provided with a digital signal processing function including an amplification function, filter processing, and waveform processing. The AE signal acquisition unit 30 performs amplification and signal processing on the input AE signal and sends it to the AE evaluation unit 40.

  In this embodiment, the solid oxide fuel cell is exposed to a temperature change between 100 ° C. and 800 ° C. as a temperature load at least once, and AE inspection is performed during that time.

  The AE evaluation unit 40 evaluates the occurrence of cracks in the solid oxide fuel cell from the AE signal received from the AE signal acquisition unit 30. In this embodiment, the AE signal acquisition unit 30 estimates the occurrence of cracks and the amount of gas leak resulting from the occurrence of cracks from the integral amount of the AE signal, and the product to be inspected from the estimated amount of gas leak Quality evaluation (pass or fail) of (solid oxide fuel cell) is performed. Therefore, the AE evaluation unit 40 includes an AE signal integration amount calculation unit 41, a gas leak amount calculation unit 42, an integration amount-gas leak amount table 43, and an evaluation output unit 44. The AE signal integration amount calculation unit 41 obtains the sum of the amplitude values of the AE signal, that is, the time integration value of the AE signal as the AE signal integration amount. When excessive cooling is started, the residual stress is released and the number of microcracks increases, so the frequency of generation of pulsed AE signals increases and the amount of AE signal integration also increases. For this reason, an increase in the AE signal integration amount and an increase in microcracks, and as a result, an increase in the AE signal integration amount and an increase in the gas leak amount have a high correlation. The integral amount-gas leak amount table 43 is created based on the relational expression obtained from the correlation between the increase in the AE signal integral amount and the increase in the gas leak amount obtained experimentally, and this integral amount-gas leak amount. Using the table 43, a specific gas leak amount can be derived from an arbitrary AE signal integration amount. The gas leak amount calculation unit 42 obtains the gas leak amount from the AE signal integration amount calculated by the AE signal integration amount calculation unit 41 using the integration amount-gas leak amount table 43 and sends it to the evaluation output unit 44.

  The evaluation output unit 44 compares the threshold value of the gas leak amount set in advance with the gas leak amount calculated by the gas leak amount calculation unit 42. If the gas leak amount exceeds the threshold value, Reject the product in question.

[Another embodiment]
(1) In the above-described embodiment, the gas piping member of the solid oxide fuel cell after the surface temperature of the gas piping member 17 starts to drop to the extent that does not damage the AE sensor 3 made of a piezoelectric element in the temperature lowering process. 17 and AE inspection was started. Furthermore, it was also possible to perform AE inspection while applying a thermal load to the manufactured solid oxide fuel cell. Instead of this, the AE sensor 3 may be mounted at a suitable location in the constituent member of the solid oxide fuel cell from the start of manufacture, and inspection may be performed during manufacture. In this case, the additional temperature load device, the temperature load controller 4a, and the like are omitted.
(2) In the above-described embodiment, an example in which the AE inspection through the fuel gas flow path is performed is shown, but the AE inspection through the oxidant gas flow path can also be performed. Of course, the AE inspection may be performed through both gas flow paths.
(3) In the above-described embodiment, a temperature change between 100 ° C. and 800 ° C. was given to the solid oxide fuel cell as a temperature load. The overcooling treatment given as a load will be described below. This overcooling treatment gives the solid oxide fuel cell a temperature change from room temperature to about 20 ° C. below zero, during which AE inspection is performed. FIG. 4 shows a functional block diagram of this another embodiment. Compared with the equipment shown in FIG. 3, the difference is that an overcooling mechanism 61 controlled by the temperature load controller 4a is provided.

  The inspection purpose of this overcooling process will be described below with reference to FIG. FIG. 5 (a) shows an estimation curve of the change over time in the amount of gas leak in the solid oxide fuel cell 1 under the condition where it is driven as a generator since it was manufactured, and the solid line is good The dotted line corresponds to an unsatisfactory product (denoted as product A) and an unfavorable product (denoted as product B). In general, since a solid oxide fuel cell is subjected to a heat treatment at a level of 1000 ° C., a residual stress is generated at room temperature. Since the driving temperature of the solid oxide fuel cell is about 800 ° C., repeated driving and stopping of the solid oxide fuel cell gives the solid oxide fuel cell a temperature load between room temperature and a high temperature of 800 ° C. . Therefore, as time elapses, cracks increase due to repeated release of residual stress and generation of residual stress, and as a result, the amount of gas leak increases over time. When the gas leak amount exceeds a predetermined threshold value: k (time point: Tk), repair or replacement is required. Therefore, in order to improve the product quality, it is important to determine the product B whose gas leak amount exceeds the threshold value k at an early time when the manufacture is completed. In order to achieve this, the present invention incorporates an overcooling process at the final stage of manufacture. (B) in FIG. 5 is a guess curve corresponding to (a) in FIG. 5 based on the knowledge of the present inventor. By applying this overcooling treatment, an increase in the amount of cracks that occurs slowly over time is increased. , Which occurs in the short term during the overcooling process. The crack amount, that is, the gas leak amount of the solid oxide fuel cell having the quality as in the product B, is likely to exceed the threshold value: k after the excessive cooling treatment (time point: T0). Thus, the solid oxide fuel cell having the quality as the product B can be removed by inspection before shipment.

  The overcooling process from 20 ° C. to 10 ° C. under zero is performed four times, and the relationship between the AE signal integration amount and the gas leak amount obtained each time is shown in FIG. In FIG. 6, the horizontal axis indicates the AE signal integration amount, and the vertical axis indicates the gas leak amount. In the gas leak amount on the vertical axis, normalization is performed by setting the initial result (result of the first overcooling process) to 1. When the measurement points obtained by the four overcooling processes are connected by an approximate straight line, a linear linear integral amount-gas leak amount relational expression is obtained.

  The above-described overcooling treatment is not performed in place of the inspection method in which the AE inspection is performed while a temperature change between 100 ° C. and 800 ° C. is applied to the solid oxide fuel cell as a temperature load, but both are performed. May be.

(4) In the above-described embodiment, the AE sensor 3 is mounted on the gas piping member 17 extending from the manifold 16, and a crack generated in the glass seal portion connecting the cell 10 and the manifold 16 is used as a detection aim. As other crack detection sights, as shown in FIG. 5 of Japanese Patent Laid-Open No. 2013-229170, a bonding region where a cell and a glass sealing plate are bonded with a crystallized glass layer, Japanese Patent Laid-Open No. 2007-2007 As shown in FIG. 1 of Japanese Patent No. 149430, a joining region where a cell and a separator are joined with a sealing material, and a cell and gas as shown in FIG. The joining area | region which joined the pipe | tube with the joining material, etc. are mentioned. However, in this AE inspection, not only the above-described joining region but also a crack generated in the cell itself can be detected.
(5) As a mounting position of the AE sensor 3, a gas supply pipe or the like that has a heat radiation function and does not have a high surface temperature is suitable. A member may be separately provided as an AE wave introducing member, and the AE sensor 3 may be attached to the AE wave introducing member.
(6) In the above-described embodiment, only one AE sensor 3 is mounted. However, a plurality of AE sensors 3 are mounted at appropriate locations, and signal processing of AE waves detected by each AE sensor 3 using a multi-channel method and An evaluation may be performed.
(7) In the above-described embodiment, as the solid oxide fuel cell, the cell 10 including the fuel electrode 11, the solid electrolyte 12, and the oxygen electrode 13, and the support 16 having the gas flow path 15 formed therein are provided. However, this is merely an example, and the present invention can be applied to solid oxide fuel cells having other structures.

  The present invention is applicable to product inspection of a solid oxide fuel cell in which residual stress is confined by heat treatment during manufacturing.

10: Cell 11: Fuel electrode 12: Solid electrolyte 13: Oxygen electrode 15: Gas flow path 16: Support body 17: Gas piping member 3: AE sensor 30: AE signal acquisition unit 4: Inspection controller 40: AE evaluation unit 41: AE signal integration amount calculation unit 42: gas leak amount calculation unit 44: evaluation output unit 5: production controller 60: heating mechanism 61: overcooling mechanism

Claims (11)

An inspection apparatus for a solid oxide fuel cell,
An AE sensor mounted on the solid oxide fuel cell;
Under conditions that the temperature load is applied to the solid oxide fuel cell, and the AE signal acquisition unit that acquires a signal from the AE sensor,
An AE evaluation unit that evaluates crack generation in the solid oxide fuel cell from the AE signal ,
The temperature load is
Including a first temperature change due to a temperature drop from a high temperature to a room temperature during manufacture of the solid oxide fuel cell;
The inspection apparatus in which the AE signal acquisition unit acquires a signal from the AE sensor and the AE evaluation unit evaluates the occurrence of the crack under a situation where a temperature load due to the first temperature change is given . The inspection apparatus according to claim 1, wherein the temperature load further includes a second temperature change between a driving temperature of the solid oxide fuel cell and room temperature.   The inspection apparatus according to claim 1, wherein the temperature load is given a plurality of times.   The said AE evaluation part is an inspection apparatus as described in any one of Claim 1 to 3 which evaluates the said crack generation based on the integration amount of the acquired AE signal.   An integral amount-gas leak amount table for deriving the gas leak amount resulting from the occurrence of cracks from the integral amount of the AE signal is provided, and quality evaluation of the solid oxide fuel cell is performed based on the derived gas leak amount. The inspection device according to claim 4 performed.   The inspection apparatus according to any one of claims 1 to 5, wherein the AE sensor is attached to a metal piping member that supplies fuel gas or oxidant gas to a solid oxide fuel cell main body. The temperature load further comprises a sub-zero temperature of below zero 15 degrees to minus 5 degrees, the third temperature change between the room temperature,
The inspection apparatus according to any one of claims 1 to 6, wherein an overcooling AE inspection is performed in which a signal from the AE sensor is acquired under a situation where the third temperature load is applied. A method for inspecting a solid oxide fuel cell, comprising:
Attaching an AE sensor to the solid oxide fuel cell;
Under conditions that the temperature load is applied to the solid oxide fuel cell, and the AE signal acquisition step of acquiring a signal from the AE sensor,
An AE evaluation step for evaluating crack generation in the solid oxide fuel cell from the AE signal ,
The temperature load is
Including a first temperature change due to a temperature drop from a high temperature to a room temperature during manufacture of the solid oxide fuel cell;
An inspection method in which a signal from the AE sensor is acquired in the AE signal acquisition step and the occurrence of the crack is evaluated in the AE evaluation step under a situation where a temperature load due to the first temperature change is given .   The inspection method according to claim 8, wherein in the AE evaluation step, the occurrence of cracks is evaluated based on an integral amount of the acquired AE signal.   A gas leak amount is derived from an integral amount of the AE signal using an integral amount-gas leak amount table for deriving a gas leak amount resulting from the occurrence of the crack, and the quality evaluation of the solid oxide fuel cell is performed based on the gas leak amount. The inspection method of Claim 9 performed. The temperature load further comprises a sub-zero temperature of below zero 15 degrees to minus 5 degrees, the third temperature change between the room temperature,
The inspection method according to any one of claims 8 to 10, further comprising an overcooling AE inspection step in which a signal from the AE sensor is acquired under a situation where the third temperature load is applied.

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