Fuel cell air tightness detection structure and detection method thereof

Abstract

The application relates to a fuel cell air tightness detection structure suitable for detecting the leakage of a fuel cell stack, comprising an air inlet unit, an air inlet pipeline unit, a first loop unit, a second loop unit and a test unit; the air inlet unit is connected with the air inlet pipeline unit and the test unit respectively; the air inlet pipeline unit is connected with the first loop unit and the second loop unit respectively; the test unit is connected with the first loop unit and the second loop unit respectively; the air inlet pipeline unit, the first loop unit and the second loop unit are connected with the fuel cell stack respectively. The application further provides a detection method for the air tightness of a fuel cell stack. The first loop unit and the second loop unit form a double-loop structure, effective gas medium flow control is carried out on the double-loop structure, the leakage value of the fuel cell stack can be effectively separated, and the reliability of the fuel cell air tightness test is improved.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a fuel cell airtightness detection structure and detection method. Background Technology

[0002] A fuel cell is a chemical device that directly converts the chemical energy of fuel into electrical energy. In the gas tightness testing of a fuel cell stack, the flow rate method is typically used to detect the gas tightness. Currently, there are two mass flow meter placement schemes for the flow rate method: Scheme 1: The mass flow meter is placed at the inlet of the fuel cell stack testing chamber. By maintaining the pressure in the testing chamber, the volume of gas injected in real time is measured to determine the leakage rate of the fuel cell stack and whether the gas tightness is acceptable. Scheme 2: The mass flow meter is placed at both the inlet and outlet of the fuel cell stack testing chamber. By maintaining the pressure in the testing chamber, the volume of gas injected in real time is measured to determine the leakage rate of the fuel cell stack and whether the gas tightness is acceptable.

[0003] While the above-mentioned methods can effectively detect leaks in fuel cell stacks, Scheme 1, when used to detect internal leaks, exhibits significant errors in its leakage values. This severely interferes with the assessment of fuel cell stack airtightness safety standards, impacting the stack's pass rate. Scheme 2, while avoiding the error issues of Scheme 1, suffers from complex procedures, difficult installation, and high costs, making it unlikely to meet practical application needs. Summary of the Invention

[0004] Based on this, the present invention provides a fuel cell airtightness testing structure and method, aiming to solve the technical problems of unreasonable structural layout, difficult installation, complex testing process, and detection errors in existing fuel cell stack airtightness testing devices. This application features a simple structure and a reasonable arrangement of components. By adjusting the arrangement of components and the control strategy of parts during testing, the flow meter can effectively detect the flow rate at the inlet or outlet of the fuel cell stack. The number of flow meters used is small, resulting in lower cost. Simultaneously, it enables effective separation of internal leakage values ​​in the fuel cell stack, thereby improving the reliability of fuel cell stack airtightness testing.

[0005] To achieve the above objectives, the embodiments of the present invention propose the following technical solutions:

[0006] A fuel cell air tightness detection structure is suitable for detecting the leakage of fuel cell stacks, including an air intake unit, an air intake pipeline unit, a first loop unit, a second loop unit, and a test unit;

[0007] The air intake unit is connected to the air intake pipeline unit and the test unit respectively; the air intake pipeline unit is connected to the first loop unit and the second loop unit respectively; the test unit is connected to the first loop unit and the second loop unit respectively; the air intake pipeline unit, the first loop unit, and the second loop unit are connected to the fuel cell stack respectively.

[0008] In a preferred embodiment, the air intake unit includes an air source, a first air pressure regulating valve, a second air pressure regulating valve, a third air pressure regulating valve, a first solenoid valve, a second solenoid valve, and a pressure transmitter.

[0009] The first pressure regulating valve is connected to the air source, the first solenoid valve, and the second solenoid valve respectively. The first solenoid valve is connected to the second pressure regulating valve, and the second solenoid valve is connected to the third pressure regulating valve. The pressure transmitter is connected to the second pressure regulating valve, the third pressure regulating valve, the air inlet pipeline unit, and the test unit respectively.

[0010] In a preferred embodiment, the pressure adjustment range of the first pressure regulating valve is greater than that of the second pressure regulating valve; and the pressure adjustment range of the second pressure regulating valve is greater than that of the third pressure regulating valve.

[0011] In a preferred embodiment, the intake manifold unit includes a third solenoid valve, a fourth solenoid valve, and a fifth solenoid valve.

[0012] The third solenoid valve is connected to the pressure transmitter, the first loop unit, and the second loop unit respectively; the fourth solenoid valve is connected to the pressure transmitter, the first loop unit, and the second loop unit respectively; and the fifth solenoid valve is connected to the pressure transmitter, the first loop unit, and the second loop unit respectively.

[0013] In a preferred embodiment, the first circuit unit includes a sixth solenoid valve, a seventh solenoid valve, an eighth solenoid valve, a ninth solenoid valve, and a first gas outlet.

[0014] The sixth solenoid valve is connected to the third solenoid valve, the second circuit unit, and the test unit; the seventh solenoid valve is connected to the fourth solenoid valve, the second circuit unit, and the test unit; the eighth solenoid valve is connected to the fifth solenoid valve, the second circuit unit, and the test unit; and the ninth solenoid valve is connected to the sixth solenoid valve, the seventh solenoid valve, the eighth solenoid valve, the first gas outlet, and the test unit.

[0015] In a preferred embodiment, the test unit includes a tenth solenoid valve, an eleventh solenoid valve, a twelfth solenoid valve, a thirteenth solenoid valve, a fourteenth solenoid valve, a fifteenth solenoid valve, a first mass flow meter, a second mass flow meter, and a third mass flow meter.

[0016] The tenth solenoid valve is connected to the sixth, seventh, eighth, ninth, eleventh, twelfth, thirteenth, fourteenth, and fifteenth solenoid valves respectively.

[0017] The eleventh solenoid valve is connected to the pressure transmitter, the third solenoid valve, the fourth solenoid valve, and the fifth solenoid valve respectively.

[0018] The twelfth solenoid valve is connected to the first mass flow meter; the thirteenth solenoid valve is connected to the second mass flow meter; and the fourteenth solenoid valve is connected to the third mass flow meter.

[0019] The first mass flow meter, the second mass flow meter, the third mass flow meter, and the fifteenth solenoid valve are respectively connected to the second circuit unit.

[0020] In a preferred embodiment, the first mass flow meter, the second mass flow meter, and the third mass flow meter are respectively connected to the fuel cell stack.

[0021] In a preferred embodiment, the flow range of the first mass flow meter is greater than that of the second mass flow meter; and the flow range of the second mass flow meter is greater than that of the third mass flow meter.

[0022] In a preferred embodiment, the second circuit unit includes a sixteenth solenoid valve, a seventeenth solenoid valve, an eighteenth solenoid valve, a nineteenth solenoid valve, and a second gas outlet;

[0023] The sixteenth solenoid valve is connected to the third solenoid valve, the sixth solenoid valve, and the oxygen chamber of the fuel cell stack; the seventeenth solenoid valve is connected to the fourth solenoid valve, the seventh solenoid valve, and the hydrogen chamber of the fuel cell stack; the eighteenth solenoid valve is connected to the fifth solenoid valve, the eighth solenoid valve, and the water chamber of the fuel cell stack.

[0024] The nineteenth solenoid valve is connected to the sixteenth solenoid valve, the seventeenth solenoid valve, the eighteenth solenoid valve, the first mass flow meter, the second mass flow meter, the third mass flow meter, the fifteenth solenoid valve, and the second gas outlet.

[0025] On the other hand, embodiments of the present invention also provide a method for detecting the airtightness of a fuel cell stack, wherein the method utilizes the fuel cell airtightness detection structure to detect the airtightness of the fuel cell stack.

[0026] The beneficial effects achieved by this invention are as follows: This application forms a dual-loop structure by combining a first loop unit and a second loop unit. This dual-loop structure enables effective control of the gas medium flow direction. The first loop unit is used for gas outflow from the fuel cell stack, and the second loop unit is used for gas inflow. This effectively separates the internal and external leakage values ​​of the fuel cell stack, improving the reliability of fuel cell gas tightness testing. The dual-loop structure allows for full utilization of each mass flow meter, enabling the detection of the fuel cell stack inlet and outlet flow rates. This reduces the number of flow meters required, lowers costs, avoids data errors from multiple flow meters, and improves testing accuracy.

[0027] The multi-electrode structure allows gas to be supplied to a specific chamber independently without passing through a mass flow meter, avoiding errors in test data due to leakage in a non-test chamber during the testing process. This structure can automatically detect all leaks in the fuel cell stack with a single button by controlling the opening and closing of the solenoid valves throughout the testing process, significantly improving detection efficiency. It is suitable for both short-stack and full-stack tests, production lines, and laboratories, offering a wide range of applications. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of a fuel cell air tightness detection structure according to an embodiment of the present invention;

[0030] Figure 2 for Figure 1 A detailed structural diagram of the fuel cell airtightness testing structure.

[0031] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, top, bottom, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0034] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] It should be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0036] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0037] Specifically, such as Figures 1 to 2 As shown, this embodiment of the invention provides a fuel cell air tightness detection structure, which is suitable for detecting the leakage of fuel cell stack 10, including an air intake unit 20, an air intake pipeline unit 30, a first loop unit 40, a second loop unit 50, and a test unit 60.

[0038] The intake unit 20 is connected to the intake pipeline unit 30 and the test unit 60 respectively; the intake pipeline unit 30 is connected to the first loop unit 40 and the second loop unit 50 respectively; the test unit 60 is connected to the first loop unit 40 and the second loop unit 50 respectively; the intake pipeline unit 30, the first loop unit 40, and the second loop unit 50 are connected to the fuel cell stack 10 respectively.

[0039] In a preferred embodiment, the air intake unit 20 includes an air source 21, a first air pressure regulating valve P1, a second air pressure regulating valve P2, a third air pressure regulating valve P3, a first solenoid valve V1, a second solenoid valve V2, and a pressure transmitter T.

[0040] The first pressure regulating valve P1 is connected to the air source 21, the first solenoid valve V1, and the second solenoid valve V2. The first solenoid valve V1 is connected to the second pressure regulating valve P2, and the second solenoid valve V2 is connected to the third pressure regulating valve P3. The pressure transmitter T is connected to the second pressure regulating valve P2, the third pressure regulating valve P3, the air inlet pipeline unit 30, and the test unit 60.

[0041] In a preferred embodiment, the pressure adjustment range of the first pressure regulating valve P1 (0-1 MPa) is greater than the pressure adjustment range of the second pressure regulating valve P2 (0-500 kPa); the pressure adjustment range of the second pressure regulating valve P2 is greater than the pressure adjustment range of the third pressure regulating valve P3 (0-200 kPa). In this embodiment, the first pressure regulating valve P1, the second pressure regulating valve P2, and the third pressure regulating valve P3 are all pressure regulating valves.

[0042] In a preferred embodiment, the intake manifold unit 30 includes a third solenoid valve V3, a fourth solenoid valve V4, and a fifth solenoid valve V5.

[0043] The third solenoid valve V3 is connected to the pressure transmitter T, the first loop unit 40, and the second loop unit 50 respectively; the fourth solenoid valve V4 is connected to the pressure transmitter T, the first loop unit 40, and the second loop unit 50 respectively; and the fifth solenoid valve V5 is connected to the pressure transmitter T, the first loop unit 40, and the second loop unit 50 respectively.

[0044] In a preferred embodiment, the first circuit unit 40 includes a sixth solenoid valve V6, a seventh solenoid valve V7, an eighth solenoid valve V8, a ninth solenoid valve V9, and a first gas outlet O1.

[0045] The sixth solenoid valve V6 is connected to the third solenoid valve V3, the second circuit unit 50, and the test unit 60, respectively; the seventh solenoid valve V7 is connected to the fourth solenoid valve V4, the second circuit unit 50, and the test unit 60, respectively; the eighth solenoid valve V8 is connected to the fifth solenoid valve V5, the second circuit unit 50, and the test unit 60, respectively; and the ninth solenoid valve V9 is connected to the sixth solenoid valve V6, the seventh solenoid valve V7, the eighth solenoid valve V8, the first gas outlet O1, and the test unit 60, respectively.

[0046] In a preferred embodiment, the test unit 60 includes a tenth solenoid valve V10, an eleventh solenoid valve V11, a twelfth solenoid valve V12, a thirteenth solenoid valve V13, a fourteenth solenoid valve V14, a fifteenth solenoid valve V15, a first mass flow meter MFM1, a second mass flow meter MFM2, and a third mass flow meter MFM3.

[0047] The tenth solenoid valve V10 is connected to the sixth solenoid valve V6, the seventh solenoid valve V7, the eighth solenoid valve V8, the ninth solenoid valve V9, the eleventh solenoid valve V11, the twelfth solenoid valve V12, the thirteenth solenoid valve V13, the fourteenth solenoid valve V14, and the fifteenth solenoid valve V15 respectively.

[0048] The eleventh solenoid valve V11 is connected to the pressure transmitter T, the third solenoid valve V3, the fourth solenoid valve V4, and the fifth solenoid valve V5 respectively.

[0049] The twelfth solenoid valve V12 is connected to the first mass flow meter MFM1; the thirteenth solenoid valve V13 is connected to the second mass flow meter MFM2; and the fourteenth solenoid valve V14 is connected to the third mass flow meter MFM3.

[0050] The first mass flow meter MFM1, the second mass flow meter MFM2, the third mass flow meter MFM3, and the fifteenth solenoid valve V15 are respectively connected to the second loop unit 50.

[0051] In a preferred embodiment, the first mass flow meter MFM1, the second mass flow meter MFM2, and the third mass flow meter MFM3 are respectively connected to the fuel cell stack 10.

[0052] In a preferred embodiment, the flow range of the first mass flow meter MFM1 (0-500 sccm) is greater than the flow range of the second mass flow meter MFM2 (0-50 sccm); the flow range of the second mass flow meter MFM2 is greater than the flow range of the third mass flow meter MFM3 (0-10 sccm).

[0053] In a preferred embodiment, the second circuit unit 50 includes a sixteenth solenoid valve V16, a seventeenth solenoid valve V17, an eighteenth solenoid valve V18, a nineteenth solenoid valve V19, and a second gas outlet O2.

[0054] The sixteenth solenoid valve V16 is connected to the third solenoid valve V3, the sixth solenoid valve V6, and the oxygen chamber (OX) of the fuel cell stack 10; the seventeenth solenoid valve V17 is connected to the fourth solenoid valve V4, the seventh solenoid valve V7, and the hydrogen chamber (FX) of the fuel cell stack 10; the eighteenth solenoid valve V18 is connected to the fifth solenoid valve V5, the eighth solenoid valve V8, and the water chamber (CX) of the fuel cell stack 10.

[0055] The nineteenth solenoid valve V19 is connected to the sixteenth solenoid valve V16, the seventeenth solenoid valve V17, the eighteenth solenoid valve V18, the first mass flow meter MFM1, the second mass flow meter MFM2, the third mass flow meter MFM3, the fifteenth solenoid valve V15, and the second gas outlet O2.

[0056] In the embodiments of this application, the connection is generally a connected connection.

[0057] On the other hand, embodiments of the present invention also provide a method for detecting the airtightness of a fuel cell stack, wherein the method utilizes the fuel cell airtightness detection structure to detect the airtightness of the fuel cell stack.

[0058] As a preferred embodiment, the fuel cell stack airtightness detection method in this application specifically includes the following steps:

[0059] (1) External leakage of the three cavities:

[0060] Air filling: When the fuel cell stack is cold, open solenoid valves V1, V11, V15, V16, V17 and V18 in sequence to introduce air into the three chambers, and wait for the pressure in the three chambers to gradually increase to 300 kPa and remain stable.

[0061] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0062] Exhaust: After the test is completed, open V19 and close V1. The air in the fuel cell stack is discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0063] (2) Hydrogen leakage from the cavity:

[0064] Air filling: When the fuel cell stack is cold, open solenoid valves V1, V3, V5, V11, V15 and V17 in sequence to introduce air into the three chambers, and wait for the pressure in the three chambers to gradually increase to 300 kPa and remain stable;

[0065] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0066] Exhaust: After the test is completed, open V16, V18 and V19, close V1, and the air in the fuel cell stack will be discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0067] (3) Oxygen leakage from the cavity:

[0068] Air filling: When the fuel cell stack is cold, open solenoid valves V1, V4, V5, V11, V15 and V16 in sequence to introduce air into the three chambers, and wait for the pressure in the three chambers to gradually increase to 300 kPa and remain stable;

[0069] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0070] Exhaust: After the test is completed, open V17, V18 and V19, close V1, and the air in the fuel cell stack will be discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0071] (4) Water leakage from the cavity:

[0072] Air filling: When the fuel cell stack is cold, open solenoid valves V1, V3, V4, V11, V15 and V18 in sequence to introduce air into the three chambers, and wait for the pressure in the three chambers to gradually increase to 300 kPa and remain stable.

[0073] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0074] Exhaust: After the test is completed, open V16, V17 and V19, close V1, and the air in the fuel cell stack will be discharged through the gas outlet O2. After the pressure has completely dropped, close all the solenoid valves of the fuel cell stack.

[0075] (5) Total leakage in the hydrogen cavity:

[0076] Air supply: When the fuel cell stack is cold, sequentially open solenoid valves V2, V11, V15, and V17 to introduce air into the FX chamber. Open valves V6, V8, and V9 to connect OX and CX to the atmosphere. Wait for the pressure in the FX chamber to gradually increase to 100 kPa and remain stable.

[0077] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0078] Exhaust: After the test is completed, open V19 and close V1. The air in the fuel cell stack is discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0079] (6) Total oxygen chamber leakage:

[0080] Air supply: When the fuel cell stack is cold, sequentially open solenoid valves V2, V11, V15, and V16 to introduce air into the OX chamber. Open valves V7, V8, and V9 to connect FX and CX to the atmosphere. Wait for the pressure in the OX chamber to gradually increase to 100 kPa and remain stable.

[0081] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0082] Exhaust: After the test is completed, open V19 and close V1. The air in the fuel cell stack is discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0083] (7) Total leakage in the water cavity:

[0084] Air supply: When the fuel cell stack is cold, sequentially open solenoid valves V2, V11, V15, and V18 to introduce air into the CX chamber. Open valves V6, V7, and V9 to connect OX and FX to the atmosphere. Wait for the pressure in the CX chamber to gradually increase to 100 kPa and remain stable.

[0085] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0086] Exhaust: After the test is completed, open V19 and close V1. The air in the fuel cell stack is discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0087] (8) Hydrogen-oxygen internal leakage:

[0088] Air supply: When the fuel cell stack is cold, sequentially open solenoid valves V2 and V4 to introduce air into the FX chamber. Open valves V6, V10, V15, V18, and V19 to connect OX and CX to the atmosphere. Allow the pressure in the FX chamber to gradually increase to 100 kPa and remain stable.

[0089] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0090] Exhaust: After the test is completed, open V17 and close V1. The air in the fuel cell stack is discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0091] (9) Oxygen-hydrogen internal leakage:

[0092] Air supply: When the fuel cell stack is cold, sequentially open solenoid valves V2 and V3 to introduce air into the OX chamber. Open valves V7, V10, V15, V18, and V19 to connect FX and CX to the atmosphere. Allow the pressure in the OX chamber to gradually increase to 100 kPa and remain stable.

[0093] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0094] Exhaust: After the test is completed, open V16 and close V1. The air in the fuel cell stack is discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0095] (10) Hydrogen-water internal leakage:

[0096] Air supply: When the fuel cell stack is cold, open solenoid valves V2 and V4 sequentially to introduce air into the FX chamber. Open valves V8, V10, V15, V16, and V19 to connect OX and CX to the atmosphere. Allow the pressure in the FX chamber to gradually increase to 200 kPa and remain stable.

[0097] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0098] Exhaust: After the test is completed, open V17 and close V1. The air in the fuel cell stack is discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0099] (11) Oxygen-water internal leakage:

[0100] Air supply: When the fuel cell stack is cold, sequentially open solenoid valves V2 and V3 to introduce air into the FX chamber. Open valves V8, V10, V15, V17, and V19 to connect FX and CX to the atmosphere. Wait for the pressure in the OX chamber to gradually increase to 200 kPa and remain stable;

[0101] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0102] Exhaust: After the test is completed, open V16 and close V1. The air in the fuel cell stack is discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0103] (12) Hydrogen-oxygen-water leakage:

[0104] Air supply: When the fuel cell stack is cold, sequentially open solenoid valves V2, V3, and V4 to introduce air into the FX and OX chambers. Open valves V8, V10, V15, and V19 to connect the CX chamber to the atmosphere. Allow the pressure in the FX and OX chambers to gradually increase to 200 kPa and remain stable.

[0105] Test: Open V12, close V15, and allow gas to flow through flowmeter MFM1 for 120 seconds. If the flow rate is less than 50 sccm, open V13, close V12, and allow gas to flow through flowmeter MFM2 for 120 seconds. If the flow rate is less than 10 sccm, open V14, close V13, and allow gas to flow through flowmeter MFM3 for 120 seconds. The program records the airtightness test results and determines whether the test is qualified according to the airtightness test standard.

[0106] Exhaust: After the test is completed, open V16 and V17 and close V1. The air in the fuel cell stack is discharged through the gas outlet O2. After the pressure has completely dropped, close all solenoid valves of the fuel cell stack.

[0107] In this embodiment, the air intake unit is mainly used to control the pressure and supply of the test gas; the air intake pipeline unit is mainly used to supply the gas medium to the fuel cell stack; the first loop unit and the second loop unit are mainly used to control the gas medium to the fuel cell stack and the test unit; the test unit is mainly used to test the amount of gas entering and leaving the fuel cell stack.

[0108] This application's structure controls gas flow into the fuel cell stack via a first loop unit, passing through first mass flow meter MFM1, second mass flow meter MFM2, and third mass flow meter MFM3. By reading the values ​​from each mass flow meter, the external gas leakage status of the fuel cell stack is determined. This application's structure also controls gas flow from inside the fuel cell stack through a second loop, passing through the same three mass flow meters. By reading the values ​​from each mass flow meter, the internal gas leakage status of the fuel cell stack is determined. In this way, by controlling the opening and closing of different solenoid valves, gas can effectively flow into or out of the fuel cell stack and pass through the testing unit, effectively separating internal leakage values ​​of the fuel cell stack and improving the reliability of fuel cell gas tightness testing.

[0109] This application employs a dual-loop structure formed by combining a first loop unit and a second loop unit. This dual-loop structure enables effective control of the gas medium flow direction. The first loop unit handles the gas outflow from the fuel cell stack, while the second loop unit handles the gas inflow. This effectively separates the internal and external leakage values ​​of the fuel cell stack, improving the reliability of fuel cell gas tightness testing. The dual-loop structure allows for full utilization of each mass flow meter, enabling the detection of both inlet and outlet flow rates of the fuel cell stack. This reduces the number of flow meters required, lowers costs, avoids data errors from multiple flow meters, and improves testing accuracy.

[0110] The multi-electrode structure allows gas to be supplied to a specific chamber independently without passing through a mass flow meter, avoiding errors in test data due to leakage in a non-test chamber during the testing process. This structure can automatically detect all leaks in the fuel cell stack with a single button by controlling the opening and closing of the solenoid valves throughout the testing process, significantly improving detection efficiency. It is suitable for both short-stack and full-stack tests, production lines, and laboratories, offering a wide range of applications.

[0111] In the description of this specification, references to terms such as "an embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0112] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style of the specification is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0113] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A fuel cell airtightness detection structure, characterized in that, It is suitable for detecting leakage in fuel cell stacks, including the air intake unit, air intake pipeline unit, first loop unit, second loop unit, and test unit; The air intake unit is connected to the air intake pipeline unit and the test unit respectively; the air intake pipeline unit is connected to the first loop unit and the second loop unit respectively; the test unit is connected to the first loop unit and the second loop unit respectively; the air intake pipeline unit, the first loop unit, and the second loop unit are connected to the fuel cell stack respectively. The air intake unit includes an air source, a first air pressure regulating valve, a second air pressure regulating valve, a third air pressure regulating valve, a first solenoid valve, a second solenoid valve, and a pressure transmitter; The first pressure regulating valve is connected to the air source, the first solenoid valve, and the second solenoid valve respectively. The first solenoid valve is connected to the second pressure regulating valve, and the second solenoid valve is connected to the third pressure regulating valve. The pressure transmitter is connected to the second pressure regulating valve, the third pressure regulating valve, the air inlet pipeline unit, and the test unit respectively. The pressure adjustment range of the first pressure regulating valve is greater than that of the second pressure regulating valve; the pressure adjustment range of the second pressure regulating valve is greater than that of the third pressure regulating valve. The intake manifold unit includes a third solenoid valve, a fourth solenoid valve, and a fifth solenoid valve. The third solenoid valve is connected to the pressure transmitter, the first loop unit, and the second loop unit respectively; the fourth solenoid valve is connected to the pressure transmitter, the first loop unit, and the second loop unit respectively; the fifth solenoid valve is connected to the pressure transmitter, the first loop unit, and the second loop unit respectively. The first circuit unit includes a sixth solenoid valve, a seventh solenoid valve, an eighth solenoid valve, a ninth solenoid valve, and a first gas outlet; The sixth solenoid valve is connected to the third solenoid valve, the second circuit unit, and the test unit; the seventh solenoid valve is connected to the fourth solenoid valve, the second circuit unit, and the test unit; the eighth solenoid valve is connected to the fifth solenoid valve, the second circuit unit, and the test unit; and the ninth solenoid valve is connected to the sixth solenoid valve, the seventh solenoid valve, the eighth solenoid valve, the first gas outlet, and the test unit. The test unit includes a tenth solenoid valve, an eleventh solenoid valve, a twelfth solenoid valve, a thirteenth solenoid valve, a fourteenth solenoid valve, a fifteenth solenoid valve, a first mass flow meter, a second mass flow meter, and a third mass flow meter; The tenth solenoid valve is connected to the sixth, seventh, eighth, ninth, eleventh, twelfth, thirteenth, fourteenth, and fifteenth solenoid valves respectively. The eleventh solenoid valve is connected to the pressure transmitter, the third solenoid valve, the fourth solenoid valve, and the fifth solenoid valve respectively. The twelfth solenoid valve is connected to the first mass flow meter; the thirteenth solenoid valve is connected to the second mass flow meter; and the fourteenth solenoid valve is connected to the third mass flow meter. The first mass flow meter, the second mass flow meter, the third mass flow meter, and the fifteenth solenoid valve are respectively connected to the second circuit unit.

2. The fuel cell airtightness detection structure according to claim 1, characterized in that, The first mass flow meter, the second mass flow meter, and the third mass flow meter are respectively connected to the fuel cell stack.

3. The fuel cell airtightness detection structure according to claim 2, characterized in that, The flow range of the first mass flow meter is greater than that of the second mass flow meter; the flow range of the second mass flow meter is greater than that of the third mass flow meter.

4. The fuel cell airtightness detection structure according to claim 3, characterized in that, The second circuit unit includes a sixteenth solenoid valve, a seventeenth solenoid valve, an eighteenth solenoid valve, a nineteenth solenoid valve, and a second gas outlet; The sixteenth solenoid valve is connected to the third solenoid valve, the sixth solenoid valve, and the oxygen chamber of the fuel cell stack; the seventeenth solenoid valve is connected to the fourth solenoid valve, the seventh solenoid valve, and the hydrogen chamber of the fuel cell stack; the eighteenth solenoid valve is connected to the fifth solenoid valve, the eighth solenoid valve, and the water chamber of the fuel cell stack. The nineteenth solenoid valve is connected to the sixteenth solenoid valve, the seventeenth solenoid valve, the eighteenth solenoid valve, the first mass flow meter, the second mass flow meter, the third mass flow meter, the fifteenth solenoid valve, and the second gas outlet.

5. A method for detecting the airtightness of a fuel cell stack, characterized in that, The method for detecting the airtightness of the fuel cell stack uses the fuel cell airtightness detection structure according to any one of claims 1 to 4 to detect the airtightness of the fuel cell stack.

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