A leakage detection device and method for a fuel cell system

Abstract

The present invention discloses a leakage detection device for a fuel cell system, comprising a plurality of sensor units arranged in a staggered manner, wherein the sensor unit comprises a diaphragm for setting an inner catalyst layer and an outer catalyst layer; the inner catalyst layer is arranged on the inner side of the diaphragm; the outer catalyst layer is arranged on the outer side of the diaphragm, and the outer catalyst layer generates a potential change by catalytic reaction with hydrogen; a first signal line and a second signal line are respectively connected to the inner catalyst layer and the outer catalyst layer, and lead out a potential signal. When hydrogen leaks, hydrogen reacts with the outer catalyst layer, causing the potential of the inner catalyst layer and the outer catalyst layer to change, and the potential is transmitted to a monitoring device through the first signal line and the second signal line; the monitoring device calculates the received potential change with the reference potential reference position, obtains the leakage point and leakage concentration of hydrogen, and displays it through a 3D fitting image.

Description

Technical Field

[0001] The present invention relates to the field of hydrogen fuel cell systems, and in particular to a leakage detection device and method for a fuel cell system. Background Art

[0002] With the vigorous development of hydrogen energy, the number of hydrogen production and hydrogen-using equipment has also increased significantly. As hydrogen is a highly active gas and is flammable and explosive, it is necessary to conduct leak detection on related equipment. Common methods of hydrogen leak detection now include in-pipeline detection and external high-level detection.

[0003] At present, the probe type detector is commonly used in the market. Although its sensitivity can reach very high and can achieve system alarm, due to its limitation of local detection, it can only be connected to the control system to alarm the entire system. This means that it can only monitor the occurrence of leakage. To further determine the leakage point, manual inspection is required one by one, which undoubtedly brings extra workload to the work and also wastes a lot of manpower and material resources.

[0004] In order to solve the above problems, the technical document with patent number 202111369245.8 discloses a method for detecting hydrogen leakage in a fuel cell system. By obtaining the drop rate of the hydrogen line pressure of the fuel cell system during the shutdown and hydrogen replenishment stage, when the drop rate exceeds the preset threshold, the hydrogen line leakage is determined, and then it is determined whether the hydrogen concentration sensor reading is abnormal. When the reading is abnormal, the leakage position of the fuel cell system is determined according to the hydrogen concentration sensor reading, and when the reading is normal, the cross-leakage position of the fuel cell system is determined by the open circuit voltage.

[0005] However, the above technical solution only has two hydrogen concentration sensors, one of which is located inside the battery stack package and the other is located outside the system. This results in that it can only roughly determine the leakage location, but cannot accurately determine the leakage location and leakage concentration.

[0006] Therefore, it is necessary for us to improve such a structure to overcome the above-mentioned defects. Summary of the invention

[0007] The object of the present invention is to provide a leakage detection device and method for a fuel cell system to solve the problems existing in the prior art.

[0008] The above technical objectives of the present invention are achieved through the following technical solutions:

[0009] A leakage detection device for a fuel cell system comprises a plurality of sensor units arranged in a longitude-latitude staggered manner, wherein the sensor units include

[0010] A membrane for providing an inner catalyst layer and an outer catalyst layer;

[0011] An inner catalyst layer, which is disposed on the inner side of the membrane;

[0012] An outer catalyst layer is arranged on the outer side of the membrane, and the outer catalyst layer generates a potential change by catalytic reaction with hydrogen;

[0013] The first signal line and the second signal line are respectively connected to the inner catalyst layer and the outer catalyst layer and lead out potential signals.

[0014] Furthermore, the main body of the sensor unit is a hollow tube structure, both ends of the hollow tube structure are sealed, the diaphragm is arranged inside the hollow tube structure, the inner catalyst layer is arranged on the inner surface of the hollow tube structure, and the outer catalyst layer is arranged on the outer surface of the hollow tube structure.

[0015] Furthermore, the membrane, the inner catalyst layer and the outer catalyst layer are made of flexible materials that are easy to bend so as to cover the surface of the hydrogen-using equipment.

[0016] A leakage detection method for a fuel cell system comprises the following steps:

[0017] S1. Covering the leak detection device on the hydrogen device so that the outer catalyst layer 3 is in contact with the surface of the hydrogen device;

[0018] S2. When hydrogen leakage occurs, hydrogen reacts with the outer catalyst layer 3, causing the potential of the inner catalyst layer 2 and the outer catalyst layer 3 to change, and is transmitted to the monitoring device through the first signal line 4 and the second signal line 5;

[0019] S3. The monitoring device calculates the received potential change with the reference potential to obtain the leakage point and leakage concentration of hydrogen, and displays it through a 3D fitting image.

[0020] Furthermore, the specific process in step S3 is as follows:

[0021] S31. Construct a rectangular coordinate system based on the sensor units staggered in longitude and latitude;

[0022] S32. Perform digital-shape fitting on the intersection points of the sensor units, and determine the leakage point and leakage concentration of the equipment through the potential changes generated at different points.

[0023] Furthermore, the specific process of step S32 is as follows:

[0024] 1) The potential change is calculated using the attenuation function model shown in formula (1);

[0025] V=V0·e -k ·C H2 (1)

[0026] Where V is the potential change, V0 is the reference potential, e is the exponential function, k is the decay constant, which reflects the sensitivity of the sensor unit to the hydrogen concentration, and C H2 is the hydrogen concentration;

[0027] 2) Based on the potential change data of multiple intersections, the potential change data are fitted using formula (2) to determine the hydrogen concentration;

[0028] V (xi,yj) =V0·e -k ·C H2(xi,yj) (2)

[0029] Among them, V (xi,yj) Indicates the measured potential value or potential change, reflecting the hydrogen concentration C H2 The reaction result at this position; V0 is the reference potential; e is the exponential function, k is the decay constant, C H2(xi,yj) is the hydrogen concentration at the position (xi, yj);

[0030] 3) Based on the fitted potential change data, the leakage location and concentration are calculated using formula (3);

[0031] E=∑ i,j (V measured (xi,yj)-V calculated (xi,yj)) 2 (3)

[0032] Where E is the total error or loss value, which represents the sum of the errors at all measurement points; ∑ i,j Sum all monitoring points (xi, yj); V measured is the actual potential value measured, V calculated is the calculated theoretical potential value;

[0033] 4) Using formula (4) to infer the hydrogen concentration based on the fitted potential change data;

[0034]

[0035] Among them, C H2 is the hydrogen concentration, k is the decay constant, V0 is the reference potential, which is the reference value of the potential, It is a natural logarithm operation, which represents the logarithmic relationship between the sensor output potential and the reference potential V0.

[0036] In summary, the present invention has the following beneficial effects:

[0037] It has high sensitivity and can accurately determine the leakage location and concentration, eliminating the need for subsequent manpower investigation. At the same time, the catalyst it uses is a new type of non-metallic catalyst, and the diaphragm uses flexible materials, so that it can fit the equipment to the greatest extent while ensuring safety, and the shape can be changed according to actual usage, greatly improving its applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a structural schematic diagram of the sensor unit described in the present invention.

[0039] Figure 2 It is a schematic diagram of the sensor unit of the present invention being woven into a leakage detection device.

[0040] Figure 3 It is a schematic diagram of the leakage detection method described in the present invention. DETAILED DESCRIPTION

[0041] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with illustrations and specific embodiments.

[0042] like Figure 1 As shown, a leakage detection device for a fuel cell system proposed by the present invention comprises a plurality of sensor units arranged in a staggered manner in longitude and latitude, wherein the sensor units include

[0043] A membrane 1, which is used to set an inner catalyst layer 2 and an outer catalyst layer 3;

[0044] An inner catalyst layer 2, which is arranged on the inner side of the membrane 1;

[0045] The outer catalyst layer 3 is arranged on the outer side of the membrane 1, and the outer catalyst layer 3 generates a potential change by catalytic reaction with hydrogen;

[0046] The first signal line 4 and the second signal line 5 are respectively connected to the inner catalyst layer 2 and the outer catalyst layer 3 and lead out potential signals.

[0047] The main body of the sensor unit is a hollow tube structure with sealed ends. The diaphragm 1 is arranged inside the hollow tube structure, the inner catalyst layer 2 is arranged on the inner surface of the hollow tube structure, and the outer catalyst layer 3 is arranged on the outer surface of the hollow tube structure.

[0048] The present application uses a novel non-metallic catalyst, such as nitrogen-doped graphene material. Compared with graphene materials, the doping of nitrogen atoms significantly improves the conductivity and catalytic activity of graphene, promotes the transfer of electrons, and thus improves the sensitivity and response speed of the sensor.

[0049] See also Figure 2The membrane 1, the inner catalyst layer 2 and the outer catalyst layer 3 are made of flexible materials that are easy to bend so as to cover the surface of the hydrogen-using equipment. The leakage detection device can be freely designed in appearance, and the structure is a three-dimensional cross structure, which is used to directly cover the surface of the equipment. When there is a leak, a potential change will occur, and the leakage position and leakage degree can be determined according to the potential change at different points.

[0050] Taking advantage of the high activity and low concentration of hydrogen and the principle that it is easy to react with certain substances, the inner and outer surfaces of hydrogen are respectively brought out as reference potential reference positions, which are woven into a mesh in the form of longitude and latitude to form a basic mesh structure. At each intersection, the monitoring intersection points brought out from the inner and outer layers are used as reference points, and the x-axis and y-axis are defined horizontally and vertically respectively. The intersection points on the axes are defined as x1, x2, ..., xn; y1, y2, ..., yn, and each intersection point is numerically fitted with the equipment model. The leakage point and leakage concentration of the equipment can be intuitively judged through the potential changes generated at different points.

[0051] See also Figure 3 , a leakage detection method for a fuel cell system, comprising the following steps:

[0052] S1. Cover the leak detection device on the hydrogen-using device so that the outer catalyst layer 3 is in contact with the surface of the hydrogen-using device; under normal circumstances, there is no catalytic reaction on the outside and inside;

[0053] S2. When hydrogen leakage occurs, hydrogen reacts with the outer catalyst layer 3, causing the potential of the inner catalyst layer 2 and the outer catalyst layer 3 to change, and is transmitted to the monitoring device through the first signal line 4 and the second signal line 5;

[0054] S3. The monitoring device calculates the received potential change with the reference potential to obtain the leakage point and leakage concentration of hydrogen, and displays it through a 3D fitting image.

[0055] The specific process in step S3 is as follows:

[0056] S31. Construct a rectangular coordinate system based on the sensor units staggered in longitude and latitude;

[0057] S32. Perform digital-shape fitting on the intersection points of the sensor units, and determine the leakage point and leakage concentration of the equipment through the potential changes generated at different points.

[0058] The specific process of step S32 is as follows:

[0059] 1) The potential change is calculated using the attenuation function model shown in formula (1);

[0060] V=V0·e-k ·C H2 (1)

[0061] Where V is the potential change, V0 is the reference potential, e is the exponential function, k is the decay constant, which reflects the sensitivity of the sensor unit to the hydrogen concentration, and C H2 is the hydrogen concentration;

[0062] 2) Based on the potential change data of multiple intersections, the potential change data are fitted using formula (2) to determine the hydrogen concentration;

[0063] V (xi,yj) =V0·e -k ·C H2(xi,yj) (2)

[0064] Among them, V (xi,yj) Indicates the measured potential value or potential change, reflecting the hydrogen concentration C H2 The reaction result at this position; V0 is the reference potential; e is the exponential function, k is the decay constant, C H2(xi,yj) is the hydrogen concentration at the position (xi, yj);

[0065] 3) Based on the fitted potential change data, the leakage location and concentration are calculated using formula (3);

[0066] E=∑ i,j (V measured (xi,yj)-V calculated (xi,yj)) 2 (3)

[0067] Where E is the total error or loss value, which represents the sum of the errors at all measurement points; ∑ i,j Sum all monitoring points (xi, yj); V measured is the actual potential value measured, V calculated is the calculated theoretical potential value;

[0068] 4) Using formula (4) to infer the hydrogen concentration based on the fitted potential change data;

[0069]

[0070] Among them, C H2 is the hydrogen concentration, k is the decay constant, V0 is the reference potential, which is the reference value of the potential, It is a natural logarithm operation, which represents the logarithmic relationship between the sensor output potential and the reference potential V0.

[0071] In this document, the directions or positional relationships indicated by terms such as "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "vertical", and "horizontal" are based on the directions or positional relationships shown in the accompanying drawings and are only for the clarity of expressing the technical solutions and the convenience of description, and therefore should not be understood as limitations of the present invention.

[0072] In this document, the terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than those listed and may also include additional elements not expressly listed.

[0073] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A leakage detection device for a fuel cell system, characterized in that: It comprises a plurality of sensor units which are staggered in longitude and latitude, and the sensor units include A membrane (1) for arranging an inner catalyst layer (2) and an outer catalyst layer (3); An inner catalyst layer (2) disposed on the inner side of the membrane (1); An outer catalyst layer (3) is arranged on the outer side of the membrane (1), and the outer catalyst layer (3) generates a potential change by catalytic reaction with hydrogen; The first signal line (4) and the second signal line (5) are respectively connected to the inner catalyst layer (2) and the outer catalyst layer (3) and lead out potential signals.

2. The leakage detection device for a fuel cell system according to claim 1, characterized in that: The main body of the sensor unit is a hollow tube structure, both ends of the hollow tube structure are sealed, the diaphragm (1) is arranged inside the hollow tube structure, the inner catalyst layer (2) is arranged on the inner surface of the hollow tube structure, and the outer catalyst layer (3) is arranged on the outer surface of the hollow tube structure.

3. The leakage detection device for a fuel cell system according to claim 1, characterized in that: The membrane (1), the inner catalyst layer (2) and the outer catalyst layer (3) are made of flexible materials that are easy to bend, so as to cover the surface of hydrogen-using equipment.

4. A leakage detection method for a fuel cell system, characterized in that: The steps include: S1. Covering the leak detection device on the hydrogen-using device so that the outer catalyst layer (3) is in contact with the surface of the hydrogen-using device; S2. When hydrogen leakage occurs, hydrogen reacts with the outer catalyst layer (3), causing the potential of the inner catalyst layer (2) and the outer catalyst layer (3) to change, and the potential is transmitted to the monitoring device through the first signal line (4) and the second signal line (5); S3. The monitoring device obtains the leakage point and leakage concentration of hydrogen by comparing and calculating the received potential change with the reference potential reference position, and displays it through a 3D fitting image.

5. The leakage detection method for a fuel cell system according to claim 4, characterized in that: The specific process in step S3 is as follows: S31. Construct a rectangular coordinate system based on the sensor units staggered in longitude and latitude; S32. Perform digital-shape fitting on the intersection points of the sensor units, and determine the leakage point and leakage concentration of the equipment through the potential changes generated at different points.

6. The leakage detection method for a fuel cell system according to claim 5, characterized in that: The specific process of step S32 is as follows: 1) The potential change is calculated using the attenuation function model shown in formula (1); V=V0·e -k ·C H2 (1) Where V is the potential change, V0 is the reference potential, e is the exponential function, k is the decay constant, which reflects the sensitivity of the sensor unit to the hydrogen concentration, and C H2 is the hydrogen concentration; 2) Based on the potential change data of multiple intersections, the potential change data are fitted using formula (2) to determine the hydrogen concentration; V (xi,yj) =V0·e -k ·C H2(xi,yj) (2) Among them, V (xi,yj) Indicates the measured potential value or potential change, reflecting the hydrogen concentration C H2 The reaction result at this position; V0 is the reference potential; e is the exponential function, k is the decay constant, C H2(xi,yj) is the hydrogen concentration at the position (xi, yj); 3) Based on the fitted potential change data, the leakage location and concentration are calculated using formula (3); E=∑ i,j (IN measured (xi,yj)-V calculated (xi,yj)) 2 (3) Where E is the total error or loss value, which represents the sum of the errors at all measurement points; ∑ i,j Sum all monitoring points (xi, yj); V measured is the actual potential value measured, V calculated is the calculated theoretical potential value; 4) Using formula (4) to infer the hydrogen concentration based on the fitted potential change data; Among them, C H2 is the hydrogen concentration, k is the decay constant, V0 is the reference potential, which is the reference value of the potential, It is a natural logarithm operation, which represents the logarithmic relationship between the sensor output potential and the reference potential V0.

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