Metal support type solid oxide fuel cell air tightness test method and system

Abstract

This invention provides a method and system for testing the airtightness of metal-supported solid oxide fuel cells. The method involves placing the battery under test in a main test chamber, connecting a reference chamber to the main test chamber via a differential pressure sensor, and simultaneously applying a vacuum to both chambers. After vacuuming, the temperatures in the main test chamber and the reference chamber are adjusted to the test temperature. Gas at the same temperature is then introduced into the main test chamber until a set pressure is reached. The leakage rate of the battery is calculated using the differential pressure value from the differential pressure sensor. If the leakage rate meets the requirements, the absolute pressure in the main test chamber and the reference chamber is reduced, and the presence of any minute leaks in the battery is determined using the differential pressure value from the differential pressure sensor. This invention also provides a battery airtightness testing system for implementing the above method. This invention is simple to operate, has high testing accuracy and precision, good safety, and can meet the airtightness testing requirements of batteries under various operating conditions, from low-temperature start-up to high-temperature operation.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide fuel cell testing technology, specifically relating to a method and system for testing the airtightness of metal-supported solid oxide fuel cells. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are all-solid-state energy conversion devices that directly convert the chemical energy of fuel into electrical energy. Among them, metal-supported solid oxide fuel cells (MS-SOFCs), due to their metal support structure, significantly improve the mechanical strength of individual cells, enhance thermal shock resistance, and reduce system costs, making them a research hotspot in the SOFC field in recent years. MS-SOFCs have advantages such as high efficiency, low emissions, and no noise, and have broad application prospects in large-scale power plants, distributed generation, residential combined heat and power systems, and automotive auxiliary power supplies. MS-SOFCs typically operate at medium-high temperatures of 600–800℃, which places stringent requirements on the chemical stability and thermal stability of the cell components, as well as the coefficient of thermal expansion matching with the connectors, to ensure good airtightness at high temperatures. Insufficient airtightness not only reduces cell performance but can also lead to explosions in severe cases. Therefore, despite the rapid development of MS-SOFCs, airtightness remains one of the key factors restricting its technological progress.

[0003] Common methods for airtightness testing include the soap bubble method, pressure drop method, differential pressure method, and hydrogen-helium leak detection method. The soap bubble method is simple to operate but has low accuracy; the soap solution may contaminate the battery surface, and it is difficult to detect areas covered by the cathode cover. The pressure drop method is simple to measure, but it requires high sealing performance of the tested object and a stable flow rate, making the experimental conditions quite demanding. The hydrogen-helium leak detection method has high accuracy but is expensive and is typically used only in aerospace and other applications with extremely high airtightness requirements. The differential pressure method has high sensitivity, is less affected by temperature and pressure fluctuations, requires simple equipment, and is relatively inexpensive, making it the primary method for airtightness testing.

[0004] Among existing patented technologies, patent CN201910311038.3 discloses a method for testing the airtightness of solid oxide fuel cells. This method involves sealing one end of the battery with a strain gauge and inserting a conduit into the other end. Changes in the strain gauge data are used to determine whether the battery has cracked due to deformation. This method is simple and has high accuracy, but it requires high sensitivity of the strain gauge and excellent sealing of the device. Furthermore, the battery may crack due to deformation during the test, posing a risk of rupture. Patent CN202020098605.X provides a fuel cell electrolyte membrane airtightness testing device and system. It uses a gas chromatograph to measure the amount of gas leaking from the first chamber into the second chamber, solving the problem of inconvenient leakage rate measurement. However, the device is expensive and only applicable to testing under normal temperature conditions, unable to assess the airtightness performance of the fuel cell at operating temperatures.

[0005] In summary, existing airtightness testing devices generally suffer from limited testing temperature ranges, failing to simultaneously meet the testing requirements under both low and high temperature conditions. Therefore, developing a simple-to-operate method for testing the airtightness of metal-supported solid oxide fuel cells that can cover both low and high temperature operating conditions and provides highly accurate test results is of significant practical importance. Summary of the Invention

[0006] This invention addresses the problems existing in the prior art by providing a method and system for testing the air tightness of metal-supported solid oxide fuel cells. It aims to solve the problem that the existing equipment is complex and has a limited detection range, which makes it impossible to detect the air tightness of MS-SOFC under actual operating conditions (-20~800℃), resulting in deviations between the test results and the air tightness under actual operating conditions.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: (I) This invention provides a method for testing the airtightness of a metal-supported solid oxide fuel cell, comprising the following steps: S1. Place the metal-supported solid oxide fuel cell to be tested into the main test chamber. Set up a reference chamber and connect it to the main test chamber through a differential pressure sensor. Start the vacuum pump to perform vacuum treatment on the main test chamber and the reference chamber at the same time. S2. After vacuum treatment, turn off the vacuum pump, start the temperature control device, adjust the temperature in the main test chamber and the reference chamber to the test temperature, and fill the main test chamber with gas at the same temperature until the set pressure is reached in the main test chamber. Stop the gas supply, keep the temperature and pressure for 10~30 minutes, record the reading change of the differential pressure sensor through the data acquisition system, and calculate the leakage rate of the battery. If the leakage rate exceeds the set value (e.g., 0.15Pa•L / s), the battery airtightness can be determined to be unqualified. S3. If the leakage rate meets the requirements, adjust the absolute pressure in the main test chamber and the reference chamber to reduce the pressure, keep it warm and pressurized for a predetermined time, and use the differential pressure value of the differential pressure sensor to determine whether there is a tiny leak in the battery.

[0008] Furthermore, in step S1, after simultaneously vacuuming the main test chamber and the reference chamber, the absolute pressure inside the main test chamber and the reference chamber is the same, which is 0.001~0.1 Pa.

[0009] Furthermore, in S2, the main test chamber and the reference chamber have the same temperature, and the test temperature is -20~800℃, which can simulate different working conditions and detect leakage caused by thermal stress.

[0010] Furthermore, in S2, the temperature rise / fall rate in the main test chamber and the reference chamber is 1~10℃ / min, and the temperature control accuracy is ±1℃.

[0011] Furthermore, in step S2, after the gas is filled, the absolute pressure inside the main test chamber is 1~20 kPa; the gas is nitrogen, helium, or a hydrogen / air mixture, and the filling flow rate is 0.5~3 L / min. The testing method of this invention can use different gases for detection, adapting to different testing conditions. When using a combustible hydrogen / air mixture, a filtration and dust removal device is activated to remove any impurities and improve the safety and accuracy of the airtightness test.

[0012] Furthermore, in S2, the formula for calculating the battery leakage rate is: Q L = V·(T0 / T)·(1 / P0)·(dP / dt); where, Q L It is the gas leakage rate (Pa·L) / s, T0 = 273.15 K, P0 = 101325 Pa, V is the volume of the main test chamber, T is the average absolute temperature during the test, and dP / dt is the pressure change rate during the pressure holding stage, which is usually taken as an absolute value.

[0013] Furthermore, in step S3, the absolute pressure in the main test chamber and the reference chamber after adjustment is 30~50 kPa; the pressure holding time is 10~30 min.

[0014] Furthermore, the metal-supported solid oxide fuel cell is held in the main test chamber by a phase change clamp.

[0015] Furthermore, the main test chamber and the reference chamber have the same volume, both ranging from 0.5 to 2 L, with a volume difference of less than 5%.

[0016] (II) The present invention also provides a metal-supported solid oxide fuel cell gas tightness testing system, including a main test chamber, a reference chamber, and a gas storage device; the main test chamber and the reference chamber are both sealed cavities, a differential pressure sensor is installed between the main test chamber and the reference chamber, and a temperature control device is installed in both the main test chamber and the reference chamber; the gas storage device can regulate the temperature of the stored gas, the gas outlet of the gas storage device is connected to the main test chamber, and the gas in the gas storage device can enter the main test chamber; the differential pressure sensor is connected to a data acquisition device for real-time recording of differential pressure changes.

[0017] Furthermore, the gas storage device includes a gas source, a filtration and dust removal device, and a gas storage tank with a temperature controller; the gas source outlet is connected to the filtration and dust removal device inlet, and the filtration and dust removal device outlet is connected to the gas storage tank inlet; an inlet valve is provided on the gas source outlet pipe; and a temperature control device is provided on the gas storage tank.

[0018] Furthermore, the main test chamber is equipped with an air inlet valve on the connecting pipe between the main test chamber and the gas storage device, the air outlet of the main test chamber is connected to the vacuum pump, and the main test chamber exhaust valve is also provided on the connecting pipe between the main test chamber and the vacuum pump; the reference chamber is connected to the vacuum pump, and the reference chamber exhaust valve is also provided on the connecting pipe between the reference chamber and the vacuum pump.

[0019] Furthermore, a phase change clamp is provided in the main test chamber for sealing and clamping the metal-supported solid oxide fuel cell. The phase change clamp is made of shape memory alloy NiTi-Al2O3 composite material. This clamp can maintain a stable clamping force within the test temperature range (-20℃~800℃), avoiding the problem of sealing failure caused by the difference in the thermal expansion coefficient of the material due to high and low temperature changes.

[0020] The beneficial effects of this invention are: (1) The test chamber of this invention adopts a dual-chamber differential pressure detection structure. By setting up a reference chamber that simultaneously undergoes vacuuming, heating, pressurization, and pressure holding processes with the main test chamber, interferences such as gas expansion due to heating or equipment deformation due to changes in ambient temperature will act equally on both the main test chamber and the reference chamber during the test. Simultaneously, the effects on the internal pressure of the two chambers are identical, and they cancel each other out on the differential pressure sensor. Therefore, the value measured by the differential pressure sensor is only the pressure change caused by battery leakage in the main test chamber, improving the sensitivity and accuracy of detection under complex temperature conditions. Experiments show that compared to the single-chamber absolute pressure method, the dual-chamber differential pressure structure of this invention reduces the measurement error by approximately 67% at 600℃.

[0021] (2) This invention combines vacuum pretreatment and micro-vacuum testing to ensure the accuracy of test data, detect minute leaks, and has high sensitivity.

[0022] (3) This invention tests the airtightness of the battery by simulating different operating temperatures, which can detect the airtightness of the battery during cold start and operation, and helps to detect leakage problems that cannot be detected by normal temperature testing.

[0023] (4) The phase change fixture of the present invention is made of shape memory alloy material, which can ensure that the fixture provides stable clamping force when the test temperature changes between high and low, and effectively avoid the problem of clamping force relaxation caused by the mismatch of the thermal expansion coefficient of the material in the test environment of high and low temperature.

[0024] (5) The present invention is simple to operate, has high testing accuracy, high precision, and good safety, and can meet the testing requirements of batteries under various working conditions from low temperature start-up to high temperature operation. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the metal-supported solid oxide fuel cell air tightness testing system of the present invention.

[0026] The labels in the attached diagram are: 1. Air source; 2. Air inlet valve; 3. Filter and dust removal device; 4. Air storage tank; 5. Main test chamber air inlet valve; 6. Main test chamber; 7. Reference chamber; 8. Differential pressure sensor; 9. Main test chamber exhaust valve; 10. Reference chamber exhaust valve; 11. Temperature control device; 12. Vacuum pump; 13. Phase change fixture; 14. Data acquisition device. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1 This invention provides a method for testing the airtightness of a metal-supported solid oxide fuel cell, comprising the following steps: Step 1: Place the 10cm × 10cm metal-supported solid oxide fuel cell to be tested (using a phase change clamp) into the main test chamber. A separate reference chamber is connected to the main test chamber via a differential pressure sensor; the reference chamber is sealed and unloaded. Start the vacuum pump to simultaneously vacuum both the main test chamber and the reference chamber, with an absolute pressure of 1 × 10⁻⁶. -2 Pa; Step 2: After vacuum treatment, turn off the vacuum pump, start the temperature control device, and simultaneously raise the temperature of the main test chamber and the reference chamber from 25°C to 600°C at a rate of 5°C / min. Then, fill the main test chamber with nitrogen gas at the same temperature until the set pressure of 10 kPa is reached in the main test chamber, at which point the gas supply is stopped. After maintaining the temperature and pressure for 20 minutes, record the changes in the differential pressure sensor readings through the data acquisition system and calculate the battery leakage rate as 0.05 Pa•L / s, which meets the requirements.

[0029] Step 3: Start the vacuum pump, adjust the absolute pressure in the main test chamber and the reference chamber to 40 kPa, maintain the temperature and pressure for 20 minutes, and use the differential pressure value of the differential pressure sensor to determine whether there is a tiny leak in the battery.

[0030] Testing revealed a leakage rate of 0.05 Pa•L / s at 600℃, with no minor leaks detected. The battery maintained good airtightness at high temperatures. This embodiment demonstrates that the dual-chamber differential pressure structure can overcome pressure measurement interference caused by gas thermal expansion during heating, thereby improving the accuracy of test results.

[0031] Example 2 This invention provides a method for testing the airtightness of a metal-supported solid oxide fuel cell, comprising the following steps: Step 1: Place the 15cm × 15cm metal-supported solid oxide fuel cell to be tested into the main test chamber. A separate reference chamber is connected to the main test chamber via a differential pressure sensor; the reference chamber is sealed and unloaded. Start the vacuum pump to simultaneously vacuum both the main test chamber and the reference chamber, with an absolute pressure of 1 × 10⁻⁶. -3 Pa; Step 2: After vacuum treatment, turn off the vacuum pump, start the temperature control device, and simultaneously raise the temperature of the main test chamber and the reference chamber from -20℃ to 400℃ at a heating rate of 2℃ / min. Then, fill the main test chamber with helium gas at the same temperature until the set pressure of 5 kPa is reached in the main test chamber, and then stop the gas supply. After maintaining the temperature and pressure for 30 minutes, record the reading changes of the differential pressure sensor through the data acquisition system and calculate the battery leakage rate as 0.02 Pa•L / s, which meets the requirements.

[0032] Step 3: Start the vacuum pump, adjust the absolute pressure in the main test chamber and the reference chamber to 30 kPa, maintain the temperature and pressure for 20 minutes, and use the differential pressure value of the differential pressure sensor to determine whether there is a tiny leak in the battery.

[0033] Tests showed that the leakage rate was 0.02 Pa•L / s during the -20℃ low-temperature start-up test and the temperature was gradually increased to 400℃. No micro-leakage points were found, and the battery exhibited good airtightness during low-temperature start-up and medium operating temperatures.

[0034] Example 3 This invention provides a method for testing the airtightness of a metal-supported solid oxide fuel cell, comprising the following steps: Step 1: Place the 15cm × 15cm metal-supported solid oxide fuel cell to be tested into the main test chamber. A separate reference chamber is connected to the main test chamber via a differential pressure sensor; the reference chamber is sealed and unloaded. Start the vacuum pump to simultaneously vacuum both the main test chamber and the reference chamber, with an absolute pressure of 1 × 10⁻⁶. -1 Pa; Step 2: After vacuum treatment, turn off the vacuum pump, start the temperature control device, and simultaneously raise the temperature of the main test chamber and the reference chamber from 50℃ to 800℃ at a rate of 1℃ / min. Then, fill the main test chamber with a filtered hydrogen / air mixture (H2 concentration of 3~5%) at the same temperature until the main test chamber reaches the set pressure of 5 kPa, then stop the gas supply. After maintaining the temperature and pressure for 10 min, record the reading changes of the differential pressure sensor through the data acquisition system and calculate the battery leakage rate as 0.08 Pa•L / s, which meets the requirements.

[0035] Step 3: Start the vacuum pump, adjust the absolute pressure in the main test chamber and the reference chamber to 35 kPa, maintain the temperature and pressure for 20 minutes, and use the differential pressure value of the differential pressure sensor to determine whether there is a tiny leak in the battery.

[0036] Testing revealed a leakage rate of 0.08 Pa·L / s at 800℃, with no minor leaks detected. Micro-vacuum testing also showed no leakage. The battery maintained a good seal even in a high-temperature, flammable gas environment, demonstrating high safety.

[0037] Example 4 This invention provides a method for testing the airtightness of a metal-supported solid oxide fuel cell, comprising the following steps: Step 1: Place the 10cm × 10cm metal-supported solid oxide fuel cell to be tested into the main test chamber. A separate reference chamber is connected to the main test chamber via a differential pressure sensor; the reference chamber is sealed and unloaded. Start the vacuum pump to simultaneously vacuum both the main test chamber and the reference chamber, with an absolute pressure of 1 × 10⁻⁶. -2 Pa; Step 2: After vacuum treatment, turn off the vacuum pump, start the temperature control device, and simultaneously raise the temperature of the main test chamber and the reference chamber from 20℃ to 500℃ at a heating rate of 2℃ / min. Then, fill the main test chamber with nitrogen gas at the same temperature until the set pressure of 1 kPa is reached in the main test chamber, and then stop the gas supply. After maintaining the temperature and pressure for 25 minutes, record the reading changes of the differential pressure sensor through the data acquisition system and calculate the battery leakage rate as 0.01 Pa•L / s, which meets the requirements.

[0038] Step 3: Start the vacuum pump, adjust the absolute pressure in the main test chamber and the reference chamber to 30 kPa, maintain the temperature and pressure for 20 minutes, and use the differential pressure value of the differential pressure sensor to determine whether there is a tiny leak in the battery.

[0039] Tests showed that under a low pressure of 1 kPa, the leakage rate was 0.01 Pa•L / s after holding the pressure for 25 minutes, and no leakage was observed during micro-vacuum testing.

[0040] Example 5 This invention provides a method for testing the airtightness of a metal-supported solid oxide fuel cell, comprising the following steps: Step 1: Place the 12cm × 12cm metal-supported solid oxide fuel cell to be tested into the main test chamber. A separate reference chamber is connected to the main test chamber via a differential pressure sensor; the reference chamber is sealed and unloaded. Start the vacuum pump to simultaneously evacuate both the main test chamber and the reference chamber, with an absolute pressure of 1 × 10⁻⁶. -3 Pa; Step 2: After vacuum treatment, turn off the vacuum pump, start the temperature control device, and simultaneously raise the temperature of the main test chamber and the reference chamber from 20℃ to 750℃ at a rate of 10℃ / min. Then, fill the main test chamber with nitrogen gas at the same temperature until the set pressure of 20 kPa is reached in the main test chamber, at which point the gas supply is stopped. After maintaining the temperature and pressure for 10 minutes, record the changes in the differential pressure sensor readings through the data acquisition system and calculate the battery leakage rate as 0.12 Pa•L / s, which meets the requirements.

[0041] Step 3: Start the vacuum pump, adjust the absolute pressure in the main test chamber and the reference chamber to 35 kPa, maintain the temperature and pressure for 20 minutes, and use the differential pressure value of the differential pressure sensor to determine whether there is a tiny leak in the battery.

[0042] Testing revealed a leakage rate of 0.12 Pa·L / s after rapid heating to 750℃ and holding at pressure for 10 minutes. A slight pressure increase was observed during the micro-vacuum test; inspection revealed a minor leak at the pipe connection. After tightening, the test was repeated, and the pressure value stabilized, indicating the test passed.

[0043] Example 6 like Figure 1 As shown, an embodiment of the present invention provides a metal-supported solid oxide fuel cell gas tightness system, including a main test chamber 6, a reference chamber 7, and a gas storage device.

[0044] Both the main test chamber 6 and the reference chamber 7 are sealed cavities. A differential pressure sensor 8 is installed between the main test chamber 6 and the reference chamber 7, and a temperature control device 11 is installed in both the main test chamber 6 and the reference chamber 7. The gas outlet of the gas storage device is connected to the main test chamber 6, and the gas in the gas storage device can enter the main test chamber 6.

[0045] The gas storage device includes a gas source 1, a filtration and dust removal device 3, and a gas storage tank 4. The outlet of the gas source 1 is connected to the inlet of the filtration and dust removal device 3, and the outlet of the filtration and dust removal device 3 is connected to the inlet of the gas storage tank 4. When a hydrogen / air mixture is introduced for airtightness testing, particulate matter present in the gas can be filtered, improving the accuracy and safety of the test. An inlet valve 2 is installed on the outlet pipe of the gas source 1, and a temperature control device is installed in the gas storage tank 4 to adjust the temperature of the gas inside the tank.

[0046] In addition, a main test chamber inlet valve 5 is installed on the connecting pipe between the main test chamber 6 and the gas storage device, the outlet of the main test chamber 6 is connected to the vacuum pump 12, and a main test chamber exhaust valve 9 is installed on the connecting pipe between the main test chamber 6 and the vacuum pump 12. The reference chamber 7 is connected to the vacuum pump 12, and a reference chamber exhaust valve 10 is installed on the connecting pipe between the reference chamber 7 and the vacuum pump 12.

[0047] In this embodiment, a phase change clamp 13 is provided in the main test chamber 6 for sealing and clamping the metal-supported solid oxide fuel cell. The material of the phase change clamp 13 is a shape memory alloy NiTi-Al2O3 composite material. The clamp can maintain a stable clamping force within the test temperature range (-20℃~800℃), avoiding the problem of sealing failure caused by the difference in the thermal expansion coefficient of the material due to high and low temperature changes.

[0048] Comparative Example 1 Comparative Example 1 is basically the same as Example 1, except that: The fixture in the main test chamber of this comparative example is made of stainless steel. During the test, when the temperature rises to 400℃, the clamping force decreases due to thermal expansion of the fixture, resulting in a significant drop in the test chamber pressure. The calculated leakage rate is 0.5 Pa•L / s. Fixtures made of conventional materials cannot maintain a stable clamping force at high temperatures due to thermal expansion, leading to sealing failure and causing deviations in the battery airtightness test results.

[0049] Comparative Example 2 Comparative Example 2 is basically the same as Example 1, except that: Comparative Example 2 uses a single test chamber and an absolute pressure sensor for detection. During the process of heating from 25℃ to 600℃ at a rate of 5℃ / min, the pressure curve fluctuates significantly due to the effects of gas thermal expansion and potential battery leakage. The calculated leakage rate is 0.15 Pa•L / s, which is significantly higher than the measured value (0.05 Pa•L / s) under the dual-chamber structure. Furthermore, it cannot effectively distinguish between the thermal expansion effect and the actual battery leakage, affecting the accuracy of the test results.

[0050] As can be seen from the test results of Examples 1-5 and Comparative Examples 1-2, the phase change fixture of the present invention is made of shape memory alloy, which can be adjusted when the test temperature changes between high and low, ensuring that the fixture provides a stable clamping force. This effectively avoids the problem of clamping force relaxation caused by the mismatch of the thermal expansion coefficients of materials under high and low temperature test environments, resulting in high accuracy of test results. The dual-chamber differential pressure detection structure adopted in the present invention can compensate for dual interferences such as temperature and pressure fluctuations through the reference chamber, solving the pressure measurement problem caused by gas thermal expansion in high and low temperature tests, realizing the measurement of the true leakage rate of the battery, and improving the sensitivity and accuracy of the detection results. The present invention utilizes a phase change fixture, temperature control, dual-chamber differential pressure detection structure, and micro-vacuum testing in synergistic testing. The dual-chamber differential pressure structure overcomes the pressure measurement interference caused by gas expansion during the heating process of a single chamber, making the leakage rate measurement results at high temperatures more accurate and reliable. Finally, micro-vacuum testing is used to supplement minor leaks, resulting in high accuracy and sensitivity of test results.

[0051] This invention integrates modules such as dual-chamber differential pressure detection, phase change fixture, high and low temperature detection, and micro-vacuum testing into one unit. The phase change fixture ensures adjustment of clamping force during high and low temperature changes, avoiding problems such as reduced clamping force or damage to sealing surfaces caused by thermal failure of conventional rigid fixtures. Pressure monitoring is then performed through dual-chamber differential pressure detection, and finally, micro-vacuum testing is used to detect minute or delayed leaks. The test results are highly accurate and sensitive. This invention is simple to operate, has high detection precision, can simulate different operating temperature conditions, and detects leaks that cannot be detected in room temperature airtightness tests.

[0052] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for testing the airtightness of a metal-supported solid oxide fuel cell, characterized in that, Includes the following steps: S1. Place the metal-supported solid oxide fuel cell to be tested into the main test chamber. Set up a reference chamber and connect it to the main test chamber through a differential pressure sensor. Perform vacuum treatment on the main test chamber and the reference chamber simultaneously. S2. After the vacuum treatment is completed, start the temperature control device, adjust the temperature in the main test chamber and the reference chamber to the test temperature, and fill the main test chamber with gas at the same temperature until the set pressure is reached in the main test chamber. After maintaining the temperature and pressure for a predetermined time, the battery leakage rate is calculated using the differential pressure value from the differential pressure sensor. S3. If the leakage rate meets the requirements, adjust the absolute pressure in the main test chamber and the reference chamber to reduce the pressure, maintain the pressure for a predetermined time, and determine whether there is a tiny leak in the battery by the differential pressure value of the differential pressure sensor.

2. The method for testing the airtightness of a metal-supported solid oxide fuel cell according to claim 1, characterized in that, In step S1, after the main test chamber and the reference chamber are simultaneously subjected to vacuum treatment, the absolute pressure inside the main test chamber and the reference chamber is the same, which is 0.001~0.1 Pa.

3. The method for testing the airtightness of a metal-supported solid oxide fuel cell according to claim 1, characterized in that, In S2, the temperature inside the main test chamber and the reference chamber is the same, and the test temperature is -20~800℃.

4. The method for testing the airtightness of a metal-supported solid oxide fuel cell according to claim 1, characterized in that, In S2, after the gas is filled, the absolute pressure inside the main test chamber is 1~20 kPa; The gas is nitrogen, helium, or a hydrogen / air mixture, and the gas flow rate is 0.5~3L / min.

5. The method for testing the airtightness of a metal-supported solid oxide fuel cell according to claim 1, characterized in that, In S2, the formula for calculating the battery leakage rate is: Q L = V·(T0 / T)·(1 / P0)·(dP / dt); Among them, Q L The gas leakage rate is given by T0 = 273.15 K, P0 = 101325 Pa, V is the volume of the main test chamber, T is the average absolute temperature during the test, and dP / dt is the pressure change rate during the pressure holding phase.

6. The method for testing the airtightness of a metal-supported solid oxide fuel cell according to claim 1, characterized in that, In S3, the absolute pressure in the main test chamber and the reference chamber after adjustment is 30~50 kPa; The pressure holding time is 10~30 min.

7. The method for testing the airtightness of a metal-supported solid oxide fuel cell according to claim 1, characterized in that, The metal-supported solid oxide fuel cell is held in the main test chamber by a phase change clamp.

8. A metal-supported solid oxide fuel cell air tightness testing system, characterized in that, It includes a main test chamber (6), a reference chamber (7), and a gas storage device; The main test chamber (6) and the reference chamber (7) are both sealed cavities. A differential pressure sensor (8) is installed between the main test chamber (6) and the reference chamber (7), and a temperature control device (11) is installed in both the main test chamber (6) and the reference chamber (7). The gas storage device can regulate the temperature of the stored gas. The gas outlet of the gas storage device is connected to the main test chamber (6), and the gas in the gas storage device can enter the main test chamber (6). The differential pressure sensor (8) is connected to the data acquisition device (14) and is used to record the differential pressure changes in real time.

9. The gas tightness testing system for a metal-supported solid oxide fuel cell according to claim 8, characterized in that, The gas storage device includes a gas source (1), a filtration and dust removal device (3), and a gas storage tank (4) with a temperature controller. The outlet of the gas source (1) is connected to the inlet of the filter dust removal device (3), and the outlet of the filter dust removal device (3) is connected to the inlet of the gas storage tank (4); an inlet valve (2) is provided on the outlet pipe of the gas source (1).

10. The gas tightness testing system for a metal-supported solid oxide fuel cell according to claim 8, characterized in that, The main test chamber (6) is connected to the gas storage device by an air inlet valve (5), the outlet of the main test chamber (6) is connected to the vacuum pump (12), and the main test chamber exhaust valve (9) is connected to the air outlet of the main test chamber (6) and the vacuum pump (12); the reference chamber (7) is connected to the vacuum pump (12), and the reference chamber exhaust valve (10) is connected to the air outlet of the reference chamber (7) and the vacuum pump (12). The main test chamber (6) is equipped with a phase change clamp (13) for clamping and fixing a metal-supported solid oxide fuel cell; the phase change clamp (13) is made of shape memory alloy NiTi-Al2O3 composite material and can automatically adjust the clamping force within the test temperature range.

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