JP2020159936A - Gas leakage inspection method and gas leakage inspection device - Google Patents

Abstract

To provide a gas leakage inspection method and a gas leakage inspection device capable of identifying gas permeation from any of a plurality of seal materials.SOLUTION: In a gas leakage inspection method, a measuring step includes: a gas amount measuring step of measuring the amount of gas to the outside of a first seal material and a second seal material in time series; and a determination step of determining a first permeation state where the gas to be inspected has permeated through the first seal material when a first inflection point of inclination of the amount of the gas to the outside per unit time is detected after the lapse of the first predetermined time after introducing the gas to be inspected, and also determining a second permeation state where the gas to be inspected has permeated through the second seal material when a second inflection point of inclination of the amount of the gas to the outside per unit time is detected.SELECTED DRAWING: Figure 4

Description

The present invention relates to a gas leak inspection method and a gas leak inspection device.

Conventionally, for example, in a unit cell of a polymer electrolyte fuel cell, gas diffusion provided on the outside of a membrane electrode assembly (MEA) in which catalyst layers are adhered to both sides of a polymer electrolyte membrane is provided. The fuel gas and oxygen or air as an oxidizing agent are introduced from the reaction gas flow path of each separator through the layer. Fuel gas is introduced into the anode and oxygen or air is introduced into the cathode. As the fuel gas, for example, hydrogen is used (see, for example, Patent Document 1). In addition, a sealing material is used to suppress hydrogen leakage.

Japanese Unexamined Patent Publication No. 2005-276729

As described above, in order to introduce, for example, hydrogen as a fuel gas into the anode of the unit cell of the polymer electrolyte fuel cell, it is necessary to measure the leakage of the fuel gas by a pressure test. Due to its small size, hydrogen molecules permeate the sealant, albeit in small amounts. For this reason, the fuel gas leaks include those due to the permeation of the sealing material and those due to the gap formed between the sealing material and the other member. Further, the sealing materials used for fuel cells, auxiliary equipment, etc. have different hydrogen transmittances.

However, in the pressure test for inspecting hydrogen leakage, the total amount of hydrogen permeation and leakage is evaluated, and it is not possible to identify from which part the permeation or leakage occurs. When it was desired to evaluate each part (material, material, shape) separately, it was necessary to design so that each circuit would be different.

An object of the present invention is to provide a gas leak inspection method and a gas leak inspection device capable of identifying which of a plurality of sealing materials permeates.

In order to achieve the above object, the present invention introduces a gas to be inspected inside a member to be inspected (for example, a fuel cell 10, a gas-liquid separator 13, an injector 33, which will be described later), and seals the member to be inspected. Gas to be inspected to the outside of the first sealing material (for example, the first sealing material (part A) described later) and the second sealing material (for example, the second sealing material (part B) described later) having different permeation coefficients. It is a gas leakage inspection method for inspecting a gas leak to the outside of the first sealing material and the second sealing material by measuring, and the measuring steps are performed on the first sealing material and the second sealing in chronological order. A gas amount measuring step for measuring the amount of gas to the outside of the material, and a first change in the inclination of the amount of gas to the outside per unit time after the first predetermined time has elapsed since the gas to be inspected was introduced. When the curved point is detected, it is determined that the gas to be inspected is in the first permeated state in which the gas to be inspected has passed through the first sealing material, and the second variable point of the inclination of the amount of gas to the outside per unit time is determined. Provided is a gas leak inspection method including a determination step of determining that the gas to be inspected has a second permeation state that has permeated the second sealing material when detected.

According to the present invention, the inflection point is detected by detecting the first inflection point and the second inflection point, and the permeation amount of each inspection target gas of the first sealing material and the second sealing material is compared. Based on the above, it is possible to differentiate the location of the sealing material through which the gas to be inspected permeates, and to identify that not only permeation but also leakage has occurred in any of the sealing materials.
In addition, since the judgment is made by obtaining the leakage amount of the entire gas to be inspected, it is not necessary to separate the parts for inspection in the product design, and it is possible to achieve both the permeation requirement and a high degree of freedom in product design. Become. As a result, a high degree of freedom in design can be realized.

Then, in the gas amount measuring step, the inspection of the outside of the first sealing material and the second sealing material so as to airtightly surround the first sealing material and the member to be inspected including the second sealing material. The pressure of the target gas is measured to inspect the gas leakage outside the first sealing material and the second sealing material.

Therefore, the pressure on the outside of the first sealing material and the second sealing material is measured so as to airtightly surround the member to be inspected including the first sealing material and the second sealing material. It is possible to detect permeation and leakage of the gas to be inspected.

Further, in the present invention, the gas introduction unit (for example, the hydrogen gas supply device 30 described later) that introduces the gas to be inspected inside the member to be inspected (for example, the fuel cell 10, the gas-liquid separation device 13, and the injector 33 described later). ) And the first sealing material (for example, the first sealing material (part A) described later) and the second sealing material (for example, the second sealing material (part) described later) having different transmission coefficients to seal the member to be inspected. A gas leak inspection device (for example, a gas leak inspection device 1 described later) including a gas measuring unit (for example, a pressure gauge 22 described later) for measuring the gas to be inspected to the outside of B), said gas measurement. The unit measures the amount of gas to the outside of the first sealing material and the second sealing material in chronological order, and after introducing the gas to be inspected, the first predetermined time (for example, the first predetermined time described later). After the lapse of time t1), when the first variation point of the inclination of the amount of gas to the outside per unit time is detected, the gas to be inspected is in the first permeation state in which the gas to be inspected has permeated the first sealing material. Judgment is made, and when the second bending point of the inclination of the amount of gas to the outside per unit time is detected, it is determined that the gas to be inspected is in the second permeation state that has permeated the second sealing material. Provided is a gas leak inspection device including a unit (for example, a determination unit 51 described later).

According to the present invention, the inflection point is detected by detecting the first inflection point and the second inflection point, and the permeation amount of each inspection target gas of the first sealing material and the second sealing material is compared. Based on the above, it is possible to differentiate the location of the sealing material through which the gas to be inspected permeates, and to identify that not only permeation but also leakage has occurred in any of the sealing materials.
In addition, since the judgment is made by obtaining the leakage amount of the entire gas to be inspected, it is not necessary to separate the parts for inspection in the product design, and it is possible to achieve both the permeation requirement and a high degree of freedom in product design. Become. As a result, a high degree of freedom in design can be realized.

Then, the gas measuring unit airtightly surrounds the member to be inspected, measures the pressure of the gas to be inspected outside the first sealing material and the second sealing material, and measures the first sealing material and the first sealing material and the said. A seal material outer inspection unit (for example, a seal material outer inspection unit 11 described later) for inspecting gas leakage on the outer side of the second seal material is provided.

Therefore, the seal material outer inspection portion is provided so as to airtightly surround the member to be inspected including the first seal material and the second seal material, and the seal is provided outside the first seal material and the second seal material. By measuring the pressure inside the inspection unit on the outside of the material, it is possible to detect permeation or leakage of the gas to be inspected in the member to be inspected.

According to the present invention, it is possible to provide a gas leak inspection method and a gas leak inspection device capable of identifying which of a plurality of sealing materials is permeating.

It is the schematic which shows the gas leak inspection apparatus by one Embodiment of this invention. It is a block diagram which shows the gas leak inspection apparatus by one Embodiment of this invention. It is a figure explaining a mode that a plurality of sealing materials in a fuel cell are inspected by the gas leak inspection apparatus according to one Embodiment of this invention. It is a graph explaining the determination of which sealant permeates by the gas leak inspection apparatus according to one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a gas leak inspection device 1. FIG. 2 is a block diagram showing a gas leak inspection device 1. FIG. 3 is a diagram illustrating a state in which a plurality of sealing materials in the fuel cell 10 are inspected by the gas leak inspection device 1. FIG. 4 is a graph for explaining the determination from which sealing material the gas leak inspection device 1 permeates.
The gas leak inspection device 1 is a device for detecting a hydrogen gas leak in a fuel cell system. Hereinafter, the gas leak inspection device 1 and the fuel cell system inspected by the gas leak inspection device 1 will be described.

The fuel cell system includes a fuel cell 10 that generates electricity by reacting hydrogen gas as an anode gas and air (air) as a cathode gas, a hydrogen gas supply device 30 that supplies hydrogen gas to the fuel cell 10, and a fuel cell 10. It has an air supply device (not shown) that supplies air to the battery, and a control device 50 that controls these.
Further, the gas leak inspection device 1 includes a gas introduction unit composed of a hydrogen gas supply device 30, a gas measurement unit composed of pressure gauges 21, 22 and 23, and a determination unit 51 composed of a control device 50. It also has a sealing material outer inspection unit 11.

The fuel cell 10 has, for example, a stack structure in which dozens to hundreds of cells are stacked. Each cell is configured by sandwiching a membrane electrode structure (MEA) between a pair of separators. The membrane electrode structure is composed of two electrodes, an anode electrode and a cathode electrode, and a solid polymer electrolyte membrane sandwiched between these electrodes. Usually, both electrodes are formed of a catalyst layer that is in contact with a solid polymer electrolyte membrane and undergoes an oxidation / reduction reaction, and a gas diffusion layer that is in contact with the catalyst layer.

In such a fuel cell 10, when hydrogen gas is supplied to an anode flow path (not shown) formed on the anode electrode side and air containing oxygen is supplied to a cathode flow path (not shown) formed on the cathode electrode side, Power is generated by these electrochemical reactions.

The hydrogen tank 32 formed of the cylinder supplies hydrogen gas to the anode flow path of the fuel cell 10 via the hydrogen supply path 35 as the anode gas supply path. An injector 33 is provided in the hydrogen supply path 35. The injector 33 recovers the hydrogen off gas flowing through the hydrogen return path 36 and returns it to the hydrogen supply path 35. In the portion of the hydrogen supply path 35 between the hydrogen tank 32 and the injector 33, a regulator 31 for reducing the pressure of hydrogen gas supplied from the hydrogen tank 32 and a pressure gauge 21 are arranged in this order upstream in the flow of hydrogen gas. It is provided from the side to the downstream side.

A hydrogen return path 36 as an anode off gas return path through which hydrogen off gas discharged from the fuel cell 10 flows is connected to the other end side of the anode flow path of the fuel cell 10. A gas-liquid separation device 13 is provided on the inlet side of the hydrogen return path 36. The tip end side of the hydrogen return path 36 is connected to the injector 33. The injector 33 recovers the hydrogen off gas flowing through the hydrogen return path 36 and returns it to the hydrogen supply path 35.

A hydrogen discharge path 37 and a scavenging gas discharge path (not shown) are branched into the gas-liquid separation device 13. The tip side of the hydrogen discharge path 37 and the scavenging gas discharge path is connected to a diluter (not shown).

The hydrogen discharge path 37 is provided with a back pressure valve 12 that opens and closes the hydrogen discharge path 37. By opening the back pressure valve 12, the gas flowing through the hydrogen recirculation passage 36 can be discharged to a diluter (not shown) at a medium flow rate. A scavenging gas exhaust valve (not shown) for opening and closing the scavenging gas discharge path is also provided in the scavenging gas discharge path (not shown).

A diluter (not shown) dilutes the hydrogen off-gas introduced through the hydrogen discharge path 37 and the scavenging gas discharge path (not shown) and discharges it to the outside of the fuel cell system.

The seal material outer inspection unit 11 is composed of a fuel cell 10, a gas-liquid separation device 13, and a container that airtightly surrounds the injector 33.

The pressure gauge 21 measures the pressure of the hydrogen gas decompressed by the regulator 31 in time series. The pressure gauge 21 is electrically connected to the control device 50, and the control device 50 calculates the amount of hydrogen gas flowing from the regulator 31 to the injector 33 based on the pressure value measured by the pressure gauge 21. To.

The pressure gauge 22 measures the pressure of hydrogen gas inside the sealing material outer inspection unit 11. The pressure gauge 22 is electrically connected to the control device 50, and the amount of hydrogen gas inside the sealing material outer inspection unit 11 is determined by the control device 50 based on the pressure value measured by the pressure gauge 22. It is calculated.

The pressure gauge 23 measures the pressure of hydrogen gas from the back pressure valve 12. The pressure gauge 23 is electrically connected to the control device 50, and the control device 50 calculates the amount of hydrogen gas from the back pressure valve 12 based on the value of the pressure measured by the pressure gauge 23.

The control device 50 has a determination unit 51. The determination unit 51 introduces hydrogen gas, which is an inspection target gas, based on the amount of hydrogen gas inside the sealing material outer inspection unit 11 based on the pressure value measured in time series by the pressure gauge 22, and then the first step. After the elapse of the predetermined time t1 (see FIG. 4) of 1, when the first turning point of the graph of the amount of gas outward per unit time is detected, the first gas to be inspected has passed through the first sealing material. When the second bending point of the graph of the amount of gas to the outside per unit time is detected after the lapse of the second predetermined time t2, the gas to be inspected permeates the second sealing material. It is determined that the second transmission state is achieved. The details of this determination will be described later.

Next, a gas leak inspection method will be described.
First, a first sealing material (part A) having a different amount of hydrogen gas permeation, which is provided in the injector 33, the fuel cell 10, and the gas-liquid separation device 13 airtightly housed by the sealing material outer inspection unit 11. A graph (inclination) of the amount of hydrogen gas permeated when hydrogen gas is permeated in each of the second sealing material (part B) and the third sealing material (part C) is acquired in advance. Specifically, the graphs (slopes) of the straight lines of the parts A, B, and C in FIG. 4 are acquired in advance.

Next, hydrogen gas, which is the gas to be inspected, is introduced from the hydrogen tank 32 inside (inside) the fuel cell 10 as the member to be inspected, the injector 33 which is an auxiliary device, and the gas-liquid separation device 13. Then, the gas amount measuring step is performed. In the gas amount measuring step, the injector 33, the fuel cell 10, and the gas-liquid separator are airtightly housed on the outside of the first sealing material, the second sealing material, and the third sealing material, that is, the sealing material outside inspection unit 11. By measuring the pressure on the outside of 13 and the inside of the sealing material outside inspection unit 11 with the pressure gauge 22, the first sealing material (part A) and the second sealing material (part B) per unit time. , The amount of hydrogen gas to the outside of the third sealing material (site C) (total amount of hydrogen gas leaked) is measured.

That is, the first sealing material (part A) and the second sealing material (part B) provided in the injector 33, the fuel cell 10, and the gas-liquid separation device 13 airtightly housed by the sealing material outer inspection unit 11, respectively. ) And the third sealing material (site C), as described above, the permeation amount of hydrogen gas is different from each other. Further, the permeation timing of hydrogen gas is different in each part A, B, and C. Therefore, when hydrogen gas does not leak and only permeates, it reaches the inflection point on the left side (first inflection point) as shown in the graph of "whole" in FIG. In the meantime, only the amount of hydrogen gas permeating is detected only in the first sealing material (site A), and a straight line graph having the first predetermined inclination is drawn.

Then, a determination step based on the drawn graph is performed. In the determination step, when the left inflection point (first inflection point) is passed after the lapse of the first predetermined time t1, hydrogen is generated in the first sealing material (part A) and the second sealing material (part B). The first predetermined inclination and the second seal are drawn by detecting the amount of gas permeating and detecting only the amount of hydrogen gas permeating only in the first sealing material (site A). A straight line graph having a slope of the sum of the second predetermined slope drawn by detecting only the amount of hydrogen gas permeating only in the material (part A) is drawn. As a result, the determination unit 51 determines that the hydrogen gas has permeated the first sealing material and started to permeate the second sealing material.

Then, after passing the right inflection point (second inflection point), the first sealing material (part A), the second sealing material (part B), and the third sealing material (part C). In, the amount of hydrogen gas permeating is detected, and only the amount of hydrogen gas permeating is detected and drawn only in the first sealing material (site A), and the first predetermined inclination and the second A second predetermined inclination drawn by detecting only the amount of hydrogen gas permeating only in the sealing material (site B) of the above, and hydrogen gas permeating only in the third sealing material (site C). Draw a straight line graph with a slope of the sum of a third predetermined slope drawn when only the quantity is detected. As a result, the determination unit 51 determines that the hydrogen gas has permeated the second sealing material and started to permeate the third sealing material.

Then, the determination unit 51 is outside the first sealing material (part A), the second sealing material (part B), and the third sealing material (part C) obtained as described above. The entire graph in which the amount of hydrogen gas was detected, the first sealing material (part A), the second sealing material (part B), and the third sealing material (part B) obtained in advance before the start of the inspection by the gas leak inspection method. By comparing with the graph of the permeation of hydrogen gas in each of the parts C), in each of the first sealing material (site A), the second sealing material (site B), and the third sealing material (site C). Compare the permeation amount of hydrogen gas. As a result, the determination unit 51 causes only permeation in the first sealing material (part A), the second sealing material (part B), and the third sealing material (part C), and leaks. Judge that no (leak) has occurred.

After starting the inspection by the gas leak inspection method and starting to introduce hydrogen gas into the fuel cell 10 and the auxiliary equipment (injector 33, gas-liquid separator 13), the first predetermined time is deviated from t1. When the inflection point of the above is detected, or when the second inflection point is detected outside the second predetermined time t2, not only the permeation in the sealing material but also leakage occurs. The determination unit 51 determines that this is the case.
Similarly, in the entire graph, the portion of the time before the first predetermined time t1 is drawn by detecting only the amount of hydrogen gas permeating only in the first sealing material (site A). When the slope is different from the predetermined slope of 1, or the time portion between the first predetermined time t1 and the second predetermined time t2 in the entire graph is the first sealing material (part A). ) Only, the amount of hydrogen gas permeating is detected and drawn, and only the first predetermined inclination and the amount of hydrogen gas permeating only in the second sealing material (site B) are detected. When the slope is different from the slope of the sum of the second predetermined slope drawn, or the part of the time after the second predetermined time t2 in the entire graph is the first sealing material (part). Only the amount of hydrogen gas permeating is detected and drawn only in A), and only the first predetermined inclination drawn and the amount of hydrogen gas permeating only in the second sealing material (site B) are detected. The slope of the sum of the second predetermined slope drawn in the above direction and the third predetermined slope drawn by detecting only the amount of hydrogen gas permeating only in the third sealing material (site C). If they have different inclinations, the determination unit 51 determines that not only permeation in the sealing material but also leakage or the like has occurred.

According to this embodiment, the following effects are achieved.
The gas leak inspection method according to the present embodiment detects the first inflection point of the graph (inclination) of the amount of gas outward per unit time after the lapse of the first predetermined time t1 after introducing the gas to be inspected. At that time, it is determined that the gas to be inspected is in the first permeation state that has permeated the first sealing material (part A), and the second inflection point of the graph (inclination) of the amount of gas outward per unit time is set. It has a determination step of determining that the gas to be inspected has passed through the second sealing material (site B) in a second permeation state when it is detected.
Further, the gas leak inspection device 1 according to the present embodiment detects the first inflection point of the graph of the amount of gas outward per unit time after the lapse of the first predetermined time t1 after the introduction of the gas to be inspected. When it is determined that the gas to be inspected is in the first permeation state that has permeated the first sealing material (site A), and the second inflection point of the graph of the amount of gas outward per unit time is detected. A determination unit 51 for determining that the gas to be inspected has passed through the second sealing material (site B) is provided in the second permeation state.

As a result, an overall graph (slope) having the first inflection point and the second inflection point, and a graph of the permeation amount of each hydrogen gas of the first sealing material, the second sealing material, and the third sealing material. By comparing with (inclination), the location of the sealing material through which hydrogen gas permeates is differentiated based on the position of the inflection point, and not only permeation but also leakage occurs in any of the sealing materials. Can be identified.
In addition, since the judgment is made by obtaining the total amount of hydrogen gas leaked, it is not necessary to separate and inspect the parts in the product design, and it is possible to achieve both the permeation requirement and a high degree of freedom in product design. .. As a result, a high degree of freedom in design can be realized.

Further, in the gas amount measuring step of the gas leak inspection method according to the present embodiment, the fuel cell 10, the gas-liquid separator 13, and the injector 33 provided with the first sealing material (part A) and the second sealing material (part B). The pressure of hydrogen gas as the gas to be inspected outside the first sealing material (part A) and the second sealing material (part B) is measured so as to airtightly surround the first sealing material and the second sealing material. Inspect for gas leaks on the outside of the. Further, the pressure gauge 22 as a gas measuring unit of the gas leak inspection device 1 according to the present embodiment airtightly surrounds the fuel cell 10, the gas-liquid separation device 13, and the injector 33, and of the first sealing material and the second sealing material. The pressure of the hydrogen gas on the outside is measured to inspect the gas leak on the outside of the first sealing material, the second sealing material, and the third sealing material.

As a result, the seal material outer inspection unit 11 is provided so as to airtightly surround the fuel cell 10, the injector 33, and the gas-liquid separation device 13 including the first seal material, the second seal material, and the third seal material. By measuring the pressure inside the first sealing material, the second sealing material, and the third sealing material, and inside the sealing material outside inspection unit 11, the fuel cell 10, the injector 33, and the gas are measured. It is possible to detect permeation or leakage of hydrogen gas in the liquid separation device 13.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.
For example, in the leak inspection method according to the present embodiment, the pressure of the hydrogen gas as the inspection target gas outside the first sealing material, the second sealing material, and the third sealing material is measured, and the pressure according to the present embodiment is also used. The gas measuring unit measures the pressure of hydrogen gas as the inspection target gas outside the first sealing material, the second sealing material, and the third sealing material, and measures the pressure of the first sealing material, the second sealing material, and the third sealing material. A gas leak on the outside of the third sealant was inspected, but is not limited to this configuration. For example, the amount of reduced hydrogen gas in the hydrogen tank 32 may be detected to determine whether the hydrogen gas has permeated or leaked (leaked).

1 ... Gas leak inspection device 10 ... Fuel cell 11 ... Seal material outside inspection unit 13 ... Gas-liquid separation device 21 ... Pressure gauge 22 ... Pressure gauge 23 ... Pressure gauge 30 ... Hydrogen gas supply device 31 ... Regulator 32 ... Hydrogen tank 33 ... Injector 51 ... Judgment unit t1 ... First predetermined time t2 ... Second predetermined time

Claims (4)

Introduce the gas to be inspected inside the member to be inspected,
The gas to be inspected to the outside of the first sealing material and the second sealing material having different transmission coefficients for sealing the member to be inspected is measured to prevent gas leakage to the outside of the first sealing material and the second sealing material. It is a gas leak inspection method to inspect
The measuring steps include a gas amount measuring step of measuring the amount of gas to the outside of the first sealing material and the second sealing material in chronological order.
After the lapse of the first predetermined time after the introduction of the gas to be inspected, when the first inflection point of the inclination of the amount of gas to the outside per unit time is detected, the gas to be inspected is the first. When it is determined that the first permeation state has passed through the sealing material and the second inflection point of the inclination of the amount of gas to the outside per unit time is detected, the gas to be inspected the second sealing material. A gas leak inspection method comprising a determination step of determining a permeated second permeated state. In the gas amount measuring step, the gas to be inspected outside the first sealing material and the second sealing material so as to airtightly surround the first sealing material and the member to be inspected including the second sealing material. The gas leak inspection method according to claim 1, wherein the pressure is measured to inspect the gas leak outside the first sealing material and the second sealing material. A gas introduction part that introduces the gas to be inspected inside the member to be inspected,
A gas leak inspection device including a first sealing material having a different transmission coefficient for sealing the member to be inspected and a gas measuring unit for measuring the gas to be inspected to the outside of the second sealing material.
The gas measuring unit measures the amount of gas to the outside of the first sealing material and the second sealing material in chronological order.
After the lapse of the first predetermined time after the introduction of the gas to be inspected, when the first inflection point of the inclination of the amount of gas to the outside per unit time is detected, the gas to be inspected is the first. When it is determined that the first permeation state has passed through the sealing material and the second inflection point of the inclination of the amount of gas to the outside per unit time is detected, the gas to be inspected the second sealing material. A gas leak inspection device including a determination unit for determining a permeated second permeated state. The gas measuring unit airtightly surrounds the member to be inspected, measures the pressure of the gas to be inspected outside the first sealing material and the second sealing material, and measures the pressure of the first sealing material and the second sealing material. The gas leak inspection device according to claim 3, further comprising a seal material outer inspection unit for inspecting a gas leak on the outside of the seal material.

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