Leakage detection device

Abstract

The utility model provides a leakage detection device. The leakage detection device comprises a vacuumizing device, a sealed low-pressure cavity and a gas sensor, the vacuumizing device is arranged outside the low-pressure cavity, is communicated with the low-pressure cavity and is used for regulating and controlling the vacuum degree of the low-pressure cavity; the gas sensor is arranged in the low-pressure cavity and used for sensing the concentration of gas generated by leakage and volatilization of the element to be detected in the low-pressure cavity. According to the gas sensor, a low-pressure environment is generated through the vacuumizing device and the low-pressure cavity, competitive adsorption of gas molecules in the environment and gas molecules volatilized by an element to be detected on the surface of the sensor is reduced, the detection sensitivity of the gas sensor is improved, and the detection limit is reduced; in the low-pressure cavity, interference of uncertain molecules in a traditional normal-pressure detection environment is effectively avoided, and the accuracy of leakage detection is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of leakage detection, in particular to a leakage detection device. Background Art

[0002] In the production process of new energy vehicles, energy storage equipment, power batteries, medical and health care, environmental protection and other industries, many components, parts or complete products have strict requirements on sealing performance. The sealing performance of the product is directly related to its performance, service life and safety, and is one of the important technical indicators for measuring product reliability. Leak detection, as a key link to ensure the sealing performance of the product, runs through the entire process of product design, manufacturing, process control, component performance verification and use. Taking new energy batteries as an example, the leakage of electrolyte will affect the battery performance and shorten the service life at the least, and may even cause catastrophic accidents such as short circuit, fire and even explosion. Therefore, the detection of electrolyte leakage is very important. In the production process, the leakage rate detection standard of the electrolyte is usually set at an extremely low 10 -8 Pa·m 3 / s level, therefore, rapid and accurate detection of low leakage rate liquid leakage is crucial to the high-quality and rapid production of these products.

[0003] At present, the detection of low-leakage rate liquid leaks mainly relies on the helium mass spectrometry leak detection method. This method requires pressurized helium immersion, static dehelium treatment, and then the leakage rate of the tracer gas helium molecules is detected by a mass spectrometer to reflect the leakage rate of the liquid to be detected. On the new energy battery production line, the pressurized helium immersion process for electrolyte leakage detection usually takes 1 hour. At the same time, the helium mass spectrometer is expensive, resulting in low efficiency and high cost problems in this detection process. In recent years, hydrogen leak detection technology has also begun to be developed to reduce the cost of leak rate detection. Unlike the helium mass spectrometry leak detection method, hydrogen leak detection technology uses hydrogen molecules as a tracer gas. The hydrogen molecules are detected by a hydrogen sensor and then reflect the leakage rate of the liquid to be detected. However, existing hydrogen sensors still have problems in terms of selectivity. In addition to hydrogen as a tracer gas, they will also react to alcohol, paint, silicon-containing adhesives, rubber, putty, etc. that are widely present in the field environment, affecting the accuracy and efficiency of detection.

[0004] Gas sensors generate light, electricity and other signal changes through the interaction between gas-sensitive materials and target gases, thereby achieving gas concentration calibration. Among them, semiconductor resistance, electrochemical, catalytic combustion and other gas sensors have the advantages of simple system, low cost and high efficiency. If the concentration of volatile substances in the liquid to be tested can be accurately detected, the tracer gas molecules can be omitted, that is, the helium or hydrogen immersion process in the helium leak detection or hydrogen leak detection method can be omitted, and in-situ real-time and high-efficiency product leak detection can be achieved. Given that the product standard leak rate is usually at an extremely low 10 -8 Pa·m 3 / s level. According to the working principle of leak detection and gas motion calculation analysis, in a test container with a diameter of 200mm and a height of 200mm, the gas concentration accumulated in the atmosphere for one hour is only about 56ppb. However, existing gas sensors are mostly designed to detect gases with concentrations at the ppm level, which makes it difficult to adapt to the detection needs of low-concentration environments. Therefore, reducing the detection limit of gas sensors to enable them to directly detect liquid molecules leaking at the ppb level, while also overcoming interference from other molecules in the environment, and achieving accurate detection of low leak rates are key issues that need to be urgently addressed in current low-leakage-rate liquid leak detection technology. Utility Model Content

[0005] The main purpose of the utility model is to provide a leakage detection device, aiming to overcome the defects of the current detection of low leakage rate liquid leakage being easily affected by environmental interference, having low sensitivity and high detection limit.

[0006] To achieve the above-mentioned purpose, the utility model provides a leakage detection device, comprising a vacuum pumping device, a sealed low-pressure cavity and a gas sensor;

[0007] The vacuum device is arranged outside the low-pressure cavity and is in communication with the low-pressure cavity, and is used to adjust the vacuum degree of the low-pressure cavity;

[0008] The gas sensor is disposed in the low-pressure cavity and is used to sense the concentration of gas generated by leakage and volatilization of the component to be tested in the low-pressure cavity.

[0009] Furthermore, it also includes a data collector, which is arranged outside the low-pressure cavity and connected to the gas sensor.

[0010] Furthermore, it also includes a data feedback system, which is arranged outside the low-pressure cavity and is communicatively connected to the data collector.

[0011] Furthermore, it also includes a measuring device arranged outside the low-pressure cavity to display the vacuum degree in the low-pressure cavity.

[0012] Furthermore, the vacuum pumping device includes a vacuum pump and an air valve, and the vacuum pump is connected to the low-pressure cavity through the air valve.

[0013] Furthermore, the vacuum pump power is one or a combination of mechanical pump, molecular pump, ion pump, diaphragm pump, cryogenic pump, and diffusion pump.

[0014] Furthermore, the gas sensor includes a semiconductor resistance gas sensor, an electrochemical gas sensor, a catalytic combustion gas sensor, an optical gas sensor, a magnetic gas analysis sensor or a surface acoustic wave gas sensor.

[0015] Furthermore, the gas sensor is a sensor whose internal gas-sensitive material is tin dioxide.

[0016] Furthermore, the component to be tested includes a new energy battery.

[0017] Furthermore, the low-pressure cavity is a closed container with a pressure lower than atmospheric pressure.

[0018] The present invention provides a leak detection device comprising: a vacuum pumping device, a sealed low-pressure cavity, and a gas sensor; the vacuum pumping device is disposed outside the low-pressure cavity and is in communication with the low-pressure cavity, for regulating the vacuum degree of the low-pressure cavity; the gas sensor is disposed within the low-pressure cavity, for sensing the concentration of gas generated by the leakage and volatilization of the component to be tested within the low-pressure cavity. In the present invention, a low-pressure environment is generated by the vacuum pumping device and the low-pressure cavity, thereby reducing the competitive adsorption of gas molecules in the environment with gas molecules volatilized by the component to be tested on the sensor surface. Compared with the normal pressure detection method, since the relative concentration of molecules in the environment that compete for adsorption with the molecules to be detected is reduced, the detection signal of the sensor has an amplifying effect on the gas concentration, thereby indirectly improving the detection sensitivity of the gas sensor and reducing the detection limit; in the low-pressure cavity, the molecules in the cavity environment are clear, which can effectively avoid the interference of uncertain molecules in the traditional normal pressure detection environment, thereby improving the accuracy of leak detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of a leakage detection device in one embodiment of the present utility model;

[0020] Figure 2 It is another structural schematic diagram of the leakage detection device in one embodiment of the utility model.

[0021] The implementation, functional features and advantages of the present invention will be further described in conjunction with embodiments and with reference to the accompanying drawings.

[0022] 1. Vacuum pump; 2. Air valve; 3. Component to be tested; 4. Vacuum dial; 5. Gas sensor; 6. Low-pressure chamber; 7. Data collector; 8. Data feedback system. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] Reference Figure 1 as well as Figure 2, in one embodiment of the present utility model, a leakage detection device is provided, comprising a vacuum pumping device, a sealed low-pressure cavity 6 and a gas sensor 5;

[0025] The vacuum pumping device is arranged outside the low-pressure cavity 6 and is in communication with the low-pressure cavity 6, and is used to adjust the vacuum degree of the low-pressure cavity 6;

[0026] The gas sensor 5 is disposed in the low-pressure cavity 6 and is used to sense the concentration of gas generated by leakage and volatilization of the component to be tested 3 in the low-pressure cavity 6 .

[0027] In this embodiment, the above-mentioned low-pressure cavity 6 is used to place the component to be tested (such as a new energy battery) in a low-pressure environment to ensure that the pressure of the external environment of the component to be tested is controllable; the above-mentioned low-pressure cavity 6 provides a relatively closed low-pressure space for the component to be tested, ensuring that the external environmental gas does not interfere with the detection process, and the cavity itself does not allow gas leakage, so that the low-pressure environment can be accurately controlled and maintained.

[0028] The gas sensor 5 is installed inside the low-pressure cavity 6 and is used to detect volatile molecules generated by liquid or gas in the component to be tested. The gas sensor 5 can be a semiconductor resistance gas sensor 5, an electrochemical gas sensor 5 or a catalytic combustion gas sensor 5;

[0029] The above vacuum device is connected to the low-pressure chamber 6 and is used to reduce the air pressure in the chamber to a desired level, which can achieve different levels of low-pressure states. For different characteristics of the liquid or gas molecules to be detected, the air pressure in the low-pressure chamber 6 can be adjusted to optimize the leak detection effect. When the pressure inside the low-pressure chamber 6 reaches a preset level (such as 10 -9 ~10 5 Pa), and keep the component to be tested leaking in this environment.

[0030] In this embodiment, the gas concentration amplification effect in a low-pressure environment greatly improves the detection sensitivity of the sensor. Under low-pressure conditions, the number of molecules that compete with the gas to be tested for adsorption per unit volume decreases, and relatively speaking, the proportion of leaked gas molecules increases significantly. The increase in relative concentration allows even a trace amount of liquid to be tested to leak, resulting in a sufficiently high relative gas concentration in a low-pressure environment, thereby enhancing the detection capability of the gas sensor 5. This is equivalent to achieving amplification of the gas concentration through a low-pressure environment, allowing the gas sensor 5 to operate at a lower gas concentration, thereby indirectly improving the detection sensitivity of the gas sensor 5 and lowering the detection limit. In a low-pressure environment, the liquid or gas molecules to be detected are more volatile, which helps to achieve an accurately detectable gas molecule concentration in a relatively short period of time. In low-pressure environment detection, since the molecules in the environment are clear, the influence of uncertain molecules in the traditional normal pressure environment on the gas sensor 5 can be effectively avoided. 10 in a low-pressure environment using the gas sensor 5 -8 Pa·m 3 / s level element liquid or gas leakage detection, replacing the traditional helium mass spectrometry and hydrogen leak detection methods, has the advantages of simple preparation process and low cost, and is easy to industrial application.

[0031] In one embodiment, the leakage detection device further includes a data collector 7, which is disposed outside the low-pressure chamber 6 and connected to the gas sensor 5. The data collector 7 can be used to obtain data collected by the gas sensor 5 for subsequent analysis.

[0032] In this embodiment, the data collector 7 is primarily used to record, process, and analyze the detection data from the gas sensor 5. The data collector 7 is connected to the gas sensor 5 within the low-pressure chamber 6. Being compact and portable, the data collector 7 can accurately capture the dynamic changes in gas concentration when the liquid under test leaks, and present a visual curve on the display screen. Based on this hardware, the leak rate of the component under test 3 can be ultimately determined by the volume and leakage time of the low-pressure chamber 6. By properly setting the component threshold, a signal alarm is issued for components with substandard leak rates, and re-inspection is performed. If the re-inspection again fails to meet the standard, the leak detection product can be scrapped.

[0033] In one embodiment, the leakage detection device further includes a data feedback system 8 (e.g., a terminal computer), which is disposed outside the low-pressure chamber 6 and is in communication with the data collector 7. The data processed by the data collector 7 can be transmitted to the data feedback system 8 via a network for storage and management.

[0034] In one embodiment, the leakage detection device further comprises a measuring device disposed outside the low-pressure cavity 6 , which comprises a vacuum dial 4 for displaying the vacuum degree in the low-pressure cavity 6 .

[0035] In one embodiment, a vacuum dial 4 is installed on the top of the low-pressure cavity 6 to display the vacuum level inside the cavity in real time.

[0036] In one embodiment, two valves are provided on the outside of the low-pressure chamber 6, one of which is connected to the external vacuum pump 1; the other is a needle valve connected to a micro-syringe, which is used to accurately inject an electrolyte of a specified concentration for leak detection testing during the testing phase.

[0037] In one embodiment, the vacuum pumping device includes a vacuum pump 1 and an air valve 2 , and the vacuum pump 1 is connected to the low-pressure chamber 6 through the air valve 2 .

[0038] In one embodiment, the vacuum pump 1 is one or a combination of a mechanical pump, a molecular pump, an ion pump, a diaphragm pump, a cryogenic pump, and a diffusion pump; the power of the vacuum pump 1 is 0.18 kW. The vacuum pump 1 is connected to the air valve 2 via a rubber hose. The vacuum pump 1 is used to reduce the pressure in the chamber to the required vacuum level to meet subsequent testing requirements.

[0039] In this embodiment, the vacuum pump 1 performs a vacuum operation on the low-pressure chamber 6. According to the type of the DUT 3, the detection requirements and the molecular structure of the liquid in the DUT 3, the pressure of the low-pressure chamber 6 is adjusted to a predetermined low-pressure state, usually within 10 -9 to 10 5 The low-pressure environment in the low-pressure chamber 6 can be adjusted based on the chemical composition of the liquid in the test element 3 and the linear response range of the corresponding sensor. For example, for highly volatile components of the test liquid, a higher pressure can be selected; for less volatile components, a lower pressure can be used to promote diffusion and volatilization of the test liquid through the leak hole.

[0040] In one embodiment, the gas sensor 5 includes a semiconductor resistive gas sensor, an electrochemical gas sensor, a catalytic combustion gas sensor, an optical gas sensor, a magnetic gas analysis sensor or a surface acoustic wave gas sensor, that is, includes at least one of the above sensors.

[0041] In one embodiment, the gas sensor 5 is constructed with tin dioxide as its internal gas-sensing material. This gas-sensing material exhibits relatively stable sensitivity when detecting volatile organic compounds (VOCs). The gas sensor 5 has an operating resistance of 40 kΩ and contains two independent circuits: one for sensor heating and the other for gas detection. Both circuits require a 5V power supply. The heating circuit maintains the sensor's necessary operating temperature.

[0042] In one embodiment, the device under test 3 includes a new energy battery.

[0043] In one embodiment, the low-pressure chamber 6 is a sealed container with a pressure lower than atmospheric pressure, and is a vacuum vessel, which is composed of a hemispherical cover and a truncated cone bottom, and has a volume of 10L.

[0044] In summary, the leakage detection device provided in the embodiment of the present invention includes: a vacuum device, a sealed low-pressure chamber 6, and a gas sensor 5; the vacuum device is arranged outside the low-pressure chamber 6 and is connected to the low-pressure chamber 6, and is used to control the vacuum degree of the low-pressure chamber 6; the gas sensor 5 is arranged in the low-pressure chamber 6, and is used to sense the concentration of gas generated by the leakage and volatilization of the component to be detected 3 in the low-pressure chamber 6. In the present invention, a low-pressure environment is generated by the vacuum device and the low-pressure chamber 6. Compared with the normal pressure detection method, the relative concentration of molecules in the environment that compete with the molecules to be detected for adsorption is reduced, and the detection signal of the sensor has an amplification effect on the gas concentration, thereby indirectly improving the detection sensitivity of the gas sensor 5 and reducing the detection limit; in the low-pressure chamber 6, the molecules in the cavity environment are clear, which can effectively avoid the interference of uncertain molecules in the traditional normal pressure detection environment, thereby improving the accuracy of leak detection.

[0045] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, apparatus, article, or method comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, apparatus, article, or method. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, apparatus, article, or method comprising the element.

[0046] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A leakage detection device, characterized in that: It includes a vacuum device, a sealed low-pressure cavity and a gas sensor; The vacuum device is arranged outside the low-pressure cavity and is in communication with the low-pressure cavity, and is used to adjust the vacuum degree of the low-pressure cavity; The gas sensor is disposed in the low-pressure cavity and is used to sense the concentration of gas generated by leakage and volatilization of the component to be tested in the low-pressure cavity.

2. The leakage detection device according to claim 1, characterized in that It also includes a data collector, which is arranged outside the low-pressure cavity and connected to the gas sensor.

3. The leakage detection device according to claim 2, characterized in that It also includes a data feedback system, which is arranged outside the low-pressure cavity and is communicatively connected with the data collector.

4. The leakage detection device according to claim 1, characterized in that It also includes a measuring device arranged outside the low-pressure cavity to display the vacuum degree in the low-pressure cavity.

5. The leakage detection device according to claim 1, characterized in that The vacuum pumping device includes a vacuum pump and an air valve, and the vacuum pump is connected to the low-pressure cavity through the air valve.

6. The leakage detection device according to claim 5, characterized in that: The vacuum pump is one or a combination of mechanical pump, molecular pump, ion pump, diaphragm pump, cryogenic pump, and diffusion pump.

7. The leakage detection device according to any one of claims 1 to 6, characterized in that: The gas sensor includes a semiconductor resistance gas sensor, an electrochemical gas sensor, a catalytic combustion gas sensor, an optical gas sensor, a magnetic gas analysis sensor or a surface acoustic wave gas sensor.

8. The leakage detection device according to any one of claims 1 to 6, characterized in that: The gas sensor is a sensor whose internal gas-sensitive material is tin dioxide.

9. The leakage detection device according to any one of claims 1 to 6, characterized in that: The component to be tested includes a new energy battery.

10. The leakage detection device according to any one of claims 1 to 6, characterized in that: The low-pressure cavity is a closed container with a pressure lower than the atmospheric pressure.

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