Equipment and method for testing the high pressure resistance of hydrogen storage cylinder inner liner

Abstract

This invention innovates a high-pressure resistance testing equipment and method for hydrogen storage cylinder liners. By simultaneously applying high pressure inside and outside the liner, controlling the temperature of the pressure medium, and controlling the axial movement of the BOSS structure on the right side of the liner according to the pressure of the medium, the service performance of the non-pressure-bearing liner under high-pressure conditions can be directly tested. Furthermore, by manufacturing a recyclable, easily processed, non-pressure-bearing rigid shell outside the liner, the deformation of the liner during testing is controlled in a low-cost and efficient manner to be consistent with the deformation of the liner in the hydrogen storage cylinder. More importantly, addressing the problem of difficulty in transmitting signals externally via wired connections in high-pressure containers, a high-pressure resistant signal line interface structure and related extension structures are designed to achieve wired signal transmission between high and low pressure.

Description

Technical Field

[0001] This invention relates to the field of special equipment technology, specifically to a device and method for testing the high-pressure resistance performance of the inner liner of a hydrogen storage cylinder. Technical Background

[0002] Type IV hydrogen storage cylinders with plastic liners, representing fully wound composite hydrogen storage cylinders, are significant for promoting efficient storage and transportation in the hydrogen energy industry chain due to their lightweight advantages. The liner, as a key component, directly determines the service capacity and lifespan of the hydrogen storage cylinder. The key to evaluating the quality of the liner lies in accurately locating and evaluating the material properties of the liner, as well as the stress-strain conditions under high-pressure environments after the liner is formed and wound with fiber composites. However, hydrogen storage cylinder liners cannot withstand high internal and external pressure differences independently (typically, the liner will undergo severe deformation and may explode under internal and external pressure differences exceeding 1 MPa; the larger the liner size, the smaller the ultimate pressure difference it can withstand; 1 MPa is far from meeting the design and testing requirements of 35 MPa, 70 MPa, etc., for hydrogen storage cylinders). Therefore, current evaluations of liner quality only include testing the material properties of the liner and testing the entire cylinder after it is fully wound, lacking methods and equipment specifically for testing the liner under high-pressure environments.

[0003] Testing the properties of materials can evaluate the performance of the liner material under service conditions and screen qualified materials, serving as an alternative evaluation method. However, material evaluation cannot assess the impact of dimensional effects on the liner structure, such as stress cracking, large deformation, local collapse, and local stress-strain caused by dimensional effects, as well as sealing failures caused by sealing rings, sealing surfaces, and sealing structures.

[0004] Evaluation of the entire hydrogen storage cylinder can comprehensively assess various properties such as the inner liner material, the cylinder seal, and the structural strength, making it the most accurate and direct evaluation method. However, direct testing of hydrogen storage cylinders involves numerous factors that can lead to failure, including inner liner failure caused by the molding process, as well as failure caused by the winding and curing processes of the carbon fiber composite. This complexity of failure factors makes it difficult to accurately pinpoint the cause of failure to optimize the inner liner structure, molding process, or winding and curing process, thus extending new product development time and increasing costs.

[0005] Therefore, developing a set of equipment that can directly test the inner liner under high pressure is of great significance for accurately studying the deformation and other physical properties of the inner liner under high pressure, improving the efficiency of hydrogen storage cylinder R&D, and reducing R&D costs.

[0006] The key to solving the challenge of testing the inner liner under high pressure alone lies in balancing the internal and external forces of the inner liner to prevent severe deformation and failure during non-service operation. Methods for balancing these forces include covering the inner liner with a pressure-bearing structure that perfectly matches its outer dimensions, and using the same gas or liquid pressure inside and outside the inner liner. The pressure-bearing structure that perfectly matches the outer dimensions of the inner liner is a fiber-wound composite material, or manufacturing a metal pressure vessel with internal dimensions roughly matching the outer dimensions of the inner liner, followed by filling the inner liner and pressure vessel with cured resin. Regardless of the method, a specific external pressure-bearing shell needs to be manufactured for each specific inner liner, essentially returning to the direct manufacturing of hydrogen storage cylinders. For example, patent 202410417856.2 provides a multi-stage pressure hydrogen permeation testing equipment and method for the inner liner of a Type IV hydrogen storage container, illustrating methods for testing the permeation performance of inner liners with different structures, which is of great significance for testing the permeation of inner liners under low-pressure conditions. However, the external protective device for the inner liner in this design still requires custom manufacturing for the specific inner liner structure; and the protective device cannot withstand high pressure. If the protective device is required to withstand high pressure, it needs to be designed as a carbon fiber layer, which again reverts to the manufacturing of the entire hydrogen storage cylinder, placing high demands on cost and development time. An alternative testing method corresponding to a pressure-bearing structure that perfectly fits the outer dimensions of the inner liner is the current high-pressure permeation testing equipment for inner liner materials. When testing the inner liner material, pressure-bearing ceramic or metal components must be placed on the low-pressure side to prevent significant deformation of the inner liner material.

[0007] Currently, there are no clear methods or equipment for balancing the internal and external gas or liquid pressures in high-pressure testing. Furthermore, a greater challenge lies in how to achieve the output of stress and strain detection signals for the inner liner under high-pressure, sealed conditions, which urgently needs to be addressed. Summary of the Invention

[0008] To avoid and overcome the technical problems existing in the prior art, this invention provides a high-pressure resistance testing device and method for hydrogen storage cylinder liners. This invention achieves direct testing of the service performance of a non-pressure-bearing liner under high-pressure conditions by simultaneously applying high pressure inside and outside the liner, controlling the temperature of the pressure medium, and controlling the axial movement of the BOSS structure on the right side of the liner according to the medium pressure. Furthermore, by manufacturing a recyclable, easily processed, non-pressure-bearing rigid shell outside the liner, the deformation of the liner during testing can be controlled in a low-cost and efficient manner to be consistent with the deformation of the liner within the hydrogen storage cylinder. More importantly, addressing the difficulty of wired detection of liner deformation under high-pressure conditions, a high-pressure resistant signal line interface structure and related extension structures are designed to achieve wired signal transmission between high and low pressure.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] The present invention discloses a high-pressure resistance testing device and method for hydrogen storage cylinder liners. The overall equipment scheme includes a cylindrical high-pressure container for accommodating the liner and whose shape is adapted to the liner. A bottle valve is coaxially sealed at the bottle opening of the front end of the high-pressure container. A BOSS displacement control system that can extend and press against the tail end of the liner to seal the front end of the bottle valve into the bottle opening of the liner is installed at the tail end of the high-pressure container. A pressure control system that can introduce the same pressure into the high-pressure container and the liner is also arranged at the bottle valve. A high-pressure resistant signal line interface structure and related expansion structure are also provided for transmitting signals from the high-pressure side to the low-pressure side. A strain detection component for detecting the deformation of the liner is also arranged at the liner being tested.

[0011] This invention discloses a high-pressure resistance testing device and method for the inner liner of a hydrogen storage cylinder. The device specifically includes a high-pressure container, a BOSS displacement control system, a pressure control system, a temperature control system, a concentration detection device, and a safety system. The high-pressure container is a high-pressure resistant, explosion-proof container made of metal or composite material winding. The BOSS displacement control system includes a BOSS fixing structure, a BOSS axial displacement control structure, and a BOSS radial displacement control structure. The pressure control system includes a pressure medium, an external pressure control device, an internal pressure control device, an internal and external pressure difference control device, a cylinder valve, and a safety relief device. The temperature control system includes a high-pressure container temperature control system, a pressure medium temperature control system, and a rapid heat exchange structure. The concentration detection device includes a hydrogen concentration detector and a data acquisition device.

[0012] The component connection relationship of the high-pressure resistance performance testing equipment and method for hydrogen storage cylinder inner liner of this invention is as follows: All components of the high-pressure container are connected by flanges, which are sealed by sealing rings or gaskets and positioned by a positioning structure. The high-pressure container remains sealed during service. A high-pressure container heating and cooling system is externally encased to control the temperature of the high-pressure container and the internal pressure medium. An insulation layer is externally encased in the heating and cooling structure. The inner liner is installed within the high-pressure container for testing. Inner holes for installing the cylinder valve and the BOSS displacement rod are respectively provided at the axial positions of the high-pressure container's end caps. A BOSS displacement rod is installed at the axial position of the right end cap of the high-pressure container. The cylindrical surface of the BOSS displacement rod is sealed to the high-pressure container by a sealing ring and can slide relative to it and move axially. The portion of the BOSS displacement rod exposed within the high-pressure container is connected to a linear motor, and the axial displacement of the BOSS displacement rod is controlled by a control system. A hydrogen concentration sensor is installed at the outlet position of the high-pressure container and on the BOSS displacement rod to monitor for leaks. The BOSS displacement rod is internally fixed to the BOSS support rod via threads. The BOSS support rod supports the inner liner and is fixedly connected to the BOSS structure of the inner liner; the BOSS support rod is slidably connected to the high-pressure vessel via a polygonal column. A bottle valve is installed at the left end cap axis of the high-pressure vessel. The bottle valve is threadedly connected to the left BOSS of the inner liner, and after the connection is complete, the bottle valve is bolted to the high-pressure vessel; a sealing ring seals the bottle valve and the high-pressure vessel. A pipe connecting to the inner liner is located at the upper axis of the bottle valve, and is sealed to the inner liner through a sealing structure used in actual operation; other locations on the bottle valve are respectively equipped with a high-pressure vessel ventilation pipe for venting gas into the high-pressure vessel and a concentration detection pipe. In addition, a signal line pipe for installing signal lines is designed. A suction device is installed on the outer end face of the bottle valve to prevent gas leakage at the bottle opening from causing danger.

[0013] The external wiring and piping corresponding to the bottle valve are as follows:

[0014] A positioning ring is coaxially fixed to the tail end of the bottle valve. Multiple guide holes are evenly spaced around the circumference of the positioning ring, with the axial direction of each guide hole parallel to the axial direction of the bottle valve. Multiple threaded holes are sequentially spaced around the circumference of the bottle opening on the front face of the high-pressure vessel. Each locking bolt passes through its corresponding guide hole and is threaded into the threaded hole to seal the bottle valve tightly at the bottle opening of the high-pressure vessel. The pressure control system includes an inner liner hydrogen / liquid compressor connected to the axial bore of the bottle valve via a pressurizing hose. An inner liner pressurizing shut-off valve, an inner liner shut-off valve, and a first pressure gauge are sequentially arranged between the inner liner hydrogen / liquid compressor and the bottle valve along the pressurization direction of the inner liner. The inner liner pressurizing shut-off valve, the inner liner shut-off valve, and the pressure gauge constitute the inner liner pipeline. A vacuum pump is also connected to the inlet end of the inner liner pipeline, and an inner liner evacuation shut-off valve is installed between the vacuum pump and the inlet end. The bottle valve is also equipped with a high-pressure container venting line connecting the inside and outside of the high-pressure container. The inner liner pressurization shut-off valve and the high-pressure container venting line are interconnected. Along the gas inlet direction of the high-pressure container, a high-pressure container pressure reducing valve and a high-pressure container shut-off valve are sequentially connected between the inner liner pressurization shut-off valve and the high-pressure container venting line. An external medium compressor is also connected to the inlet of the high-pressure container venting line. Along the gas inlet direction of the high-pressure container, an external medium shut-off valve and a second pressure gauge are sequentially connected between the external medium compressor and the high-pressure container venting line. The bottle valve is also equipped with a concentration detection line connecting the inside and outside of the high-pressure container. A mass spectrometer is connected to the inlet of the concentration detection line. Along the gas flow direction towards the mass spectrometer, a detection shut-off valve, a detection pressure reducing valve, and a third pressure gauge are sequentially connected between the concentration detection line and the mass spectrometer. The bottle valve is also provided with a signal line pipeline connecting the inside and outside of the high-pressure vessel. The signal line pipeline is sealed with a transmission line. One end of the transmission line is connected to a strain gauge attached to the surface of the inner liner, and the other end of the transmission line passes through the bottle valve and is connected to the strain processor.

[0015] In the invention of a high-pressure resistance testing equipment and method for hydrogen storage cylinder liners, the shut-off valves and branch pipes on each pipeline can be replaced by combinations of directional valves, etc.

[0016] The high-pressure container ventilation pipeline and concentration detection pipeline on the bottle valve of the present invention can be connected to a hose or metal pipe through a quick-connect fitting. The other end of the hose or metal pipe can be placed at the target inflation and deflation position in the high-pressure container.

[0017] The shape of the high-pressure container described in this invention is preferably adapted to the shape of the inner liner. Furthermore, it is preferable to manufacture and use the high-pressure containers in batches according to the size of the inner liner to be tested. For example, for small-scale hydrogen storage cylinder inner liners with a volume of less than 60L used in aircraft, a small-scale high-pressure container is manufactured; for hydrogen storage cylinder inner liners with a volume of 60L-210L used in passenger vehicles, a corresponding small-scale high-pressure container is manufactured; and for hydrogen storage cylinder inner liners with a volume of more than 210L used in commercial vehicles, a corresponding large-scale high-pressure container is manufactured.

[0018] The high-pressure vessel is preferably manufactured as a single piece, with external reinforcing ribs provided if necessary; the end caps and the shell are connected by flanges. Alternatively, the shell portion of the high-pressure vessel can be manufactured in sections to accommodate inner liner lengths. Furthermore, the exterior of the high-pressure vessel can be wrapped with fiber material to increase strength.

[0019] The heating and cooling structure described in this invention is a conventional heating jacket and cooling jacket structure. The structure is not specifically limited, but explosion-proof treatment is preferred. Examples of heating jackets include infrared heating jackets and ceramic heating jackets, while examples of cooling jackets include cooling copper pipes and liquid nitrogen cooling jackets.

[0020] In this invention, the strain gauge can be attached either inside the inner liner (if feasible) or outside the inner liner. The signal lines of the strain gauges inside the inner liner or high-pressure vessel are connected to the external signal lines through the innovative high-pressure resistant signal line interface structure of this invention.

[0021] As shown in the detailed diagram, the high-pressure resistant sealed signal line connector structure of this invention employs sealing methods such as conical sealing and labyrinth sealing. A representative structure is described, from the outside to the inside of the high-pressure pipeline (or high-pressure valve): signal line fixing plug, gasket, polymer material female connector, polymer material male connector, and high-pressure pipeline (or high-pressure valve). The signal line fixing plug is threaded to the high-pressure pipeline and sealed with an end-face sealing ring. The signal line fixed in the polymer material male connector can be inserted into the signal line fixed in the polymer material female connector. Under high pressure conditions, the polymer material is compressed, improving the sealing performance. Furthermore, since the polymer material cannot directly withstand high pressure differentials, the signal line conduit should be as small as possible, and a gasket should be used on the low-pressure side. The gasket is preferably made of ceramic or metal material, and the gasket is isolated from the signal line by an insulating material.

[0022] The conductive interface between the polymer material female connector and the polymer material male connector uses an interference fit. Preferably, as shown in the detailed drawing, at the mating position of the female and male connectors, the female connector is suspended inside and out to prevent high voltage from deforming the female connector and affecting signal transmission.

[0023] The polymer material female connector and polymer material male connector of this invention are preferably formed using high-pressure molding methods such as injection molding or compression molding to improve the density of the material. Preferably, the polymer material on the polymer material female connector and polymer material male connector can be selected from elastic materials such as rubber or nylon elastomer. Alternatively, in the bottle valve signal line pipeline, a reactive nylon elastomer can be injected for sealing. The nylon elastomer is manufactured by reaction molding or injection molding. After molding, the elastomer shrinks and tightly wraps the pipeline, and is compressed under high pressure. In addition, a longer sealing path can also improve sealing performance and reduce leakage.

[0024] In this invention, when there are many signal lines, the bottle valve signal line pipeline can also use an external signal line pipeline to prevent the cross-sectional area of ​​the polymer material female connector and the polymer material male connector from being too large, which could lead to sealing failure. Furthermore, using an external signal line pipeline allows for the acquisition of detection data while simultaneously controlling the internal pressure of the high-pressure vessel or inner liner.

[0025] The detection method of the present invention utilizes the aforementioned high-pressure resistance testing equipment for the inner liner of a hydrogen storage cylinder and includes the following basic steps:

[0026] Step 1: Place the inner liner in the high-pressure container, then assemble the segmented high-pressure container together, and seal the bottle valve at the bottle mouth of the high-pressure container. At the same time, connect all the pipelines on the bottle valve. Next, attach each strain gauge to the outer surface of the inner liner according to the set requirements. Then start the linear motor to make the BOSS support rod press against the tail end of the inner liner so that the bottle valve and the inner liner form a sealed fit.

[0027] Step 2: Based on the specific testing requirements, determine whether it is necessary to purge the air from the high-pressure container and its inner liner. If so, first open the high-pressure container shut-off valve, the inner liner evacuation shut-off valve, and the vacuum pump to extract the air from the high-pressure container and create a vacuum. Then close the high-pressure container shut-off valve and open the inner liner shut-off valve to extract the air from the inner liner and create a vacuum. Finally, close the inner liner shut-off valve, the inner liner evacuation shut-off valve, and the vacuum pump.

[0028] Step 3: Conduct service pressure tests, leakage tests, and ambient temperature cracking tests on the inner liner. For the service pressure test, first, sequentially open the inner liner hydrogen / liquid compressor, inner liner shut-off valve, inner liner pressurization shut-off valve, and high-pressure vessel shut-off valve. The test medium is then introduced into the inner liner and high-pressure vessel through the hydrogen / liquid compressor. After reaching the set pressure, the pressure is maintained for a certain time, and the deformation of the inner liner is detected based on the feedback from strain gauges as required. After the service pressure test, the inner liner pressurization shut-off valve is closed, and the inner liner evacuation shut-off valve is opened to release the pressure. After depressurization, the inner liner is removed, and its appearance and mechanical properties are tested as required. For the leakage test, after reaching the set pressure and maintaining it for a certain time during the service pressure test, the external medium shut-off valve of the high-pressure vessel is opened first. Then, nitrogen or inert gas is introduced into the high-pressure vessel through the external medium compressor. Simultaneously, the detection shut-off valve is opened, allowing the mixed gas in the high-pressure vessel to be depressurized and then introduced into the mass spectrometer. The hydrogen content in the mixed gas is analyzed in the mass spectrometer. During the service pressure test and leakage test of the inner liner, the gas entering the inner liner and high-pressure container is heated or cooled according to the test conditions.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. This invention enables direct testing of the service performance of a non-pressure-bearing inner liner under high-pressure conditions by simultaneously applying high pressure inside and outside the inner liner, controlling the temperature of the pressure medium, and controlling the axial movement of the BOSS structure on the right side of the inner liner according to the pressure of the medium.

[0031] 2. To address the difficulty of wired detection of inner liner deformation under high-voltage conditions, a high-voltage resistant signal line interface structure and related expansion structures were designed to enable wired signal transmission between high and low voltage.

[0032] 3. By manufacturing a recyclable, easy-to-process, non-pressure-bearing rigid shell on the outside of the inner liner, the deformation of the inner liner during testing is controlled in a low-cost and efficient manner to be consistent with the deformation of the inner liner in the hydrogen storage cylinder. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the principle structure of a high-pressure resistance testing device for the inner liner of a hydrogen storage cylinder according to the present invention.

[0034] Figure 2 This is a detailed schematic diagram of the bottle valve described in this invention.

[0035] Figure 3 This is a schematic diagram of the installation of the alternative inner liner and high-pressure vessel described in this invention.

[0036] Figure 4 This is a schematic diagram showing the filling of epoxy resin or the like into the gap between the inner liner and the high-pressure vessel according to the present invention.

[0037] Figure 5 This is a schematic diagram of an alternative structure for filling the gap between the inner liner and the high-pressure vessel described in this invention with epoxy resin or the like.

[0038] Figure 6 This is a schematic diagram of the high-pressure resistant sealed signal line connector structure described in this invention.

[0039] Figure 7 This is a schematic diagram of an alternative structure for the high-pressure resistant sealed signal line connector structure described in this invention.

[0040] Figure 8 This is a schematic diagram of the external signal line conduit described in this invention.

[0041] 1-High-pressure vessel; 2-High-pressure vessel heating and cooling structure; 3-High-pressure vessel insulation layer; 4-Inner liner; 401-Left side BOSS structure of the inner liner; 402-Right side BOSS structure of the inner liner; 5-BOSS support rod; 6-BOSS displacement rod; 7-Hydrogen concentration sensor; 8-Linear motor; 9-Rigid shell; 11-Strain gauge; 12-Bottle valve; 1201-High-pressure vessel venting pipeline; 1202-Concentration detection pipeline; 1203-Signal line pipeline; 1204-External signal line pipeline; 12041-Connector; 120411-Threaded head; 13-Quick connector for pipeline; 14-Hose / metal pipe; 15-High-pressure resistant sealed signal line connector structure; 1501-Polymer material male connector; 1502-Polymer material female connector; 15021-Alternative high-pressure... 1503 - Gasket; 1504 - Signal line retainer; 15041 - Outer plug of signal line retainer; 15042 - Inner plug of signal line retainer; 15043 - Screw; 16 - Evacuation device; 17 - Strain processor; 18 - First pressure gauge; 19 - Inner liner shut-off valve; 20 - Inner liner pressurization shut-off valve; 21 - Inner liner hydrogen / liquid compressor; 22 - Inner liner medium heating and cooling system; 23 - High-pressure vessel pressure reducing valve; 24 - High-pressure vessel shut-off valve; 25 - Inner liner evacuation shut-off valve; 26 - Vacuum pump; 27 - High-pressure vessel medium heating and cooling system; 28 - Second pressure gauge; 29 - High-pressure vessel external medium shut-off valve; 30 - External medium compressor; 31 - Detection shut-off valve; 32 - Detection pressure reducing valve; 33 - Third pressure gauge; 34 - Mass spectrometer. Detailed Implementation Plan

[0042] 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 some embodiments of the present invention, and 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.

[0043] like Figure 1 As shown, a testing device and method for testing the high-pressure resistance of a hydrogen storage cylinder liner includes a high-pressure container, a BOSS displacement control system, a pressure control system, a temperature control system, a concentration detection system, a strain monitoring system, and a safety system. The high-pressure container 1 is a high-pressure resistant explosion-proof container made of metal or composite material winding. The BOSS displacement control system includes a BOSS support rod 5, a BOSS displacement rod 6, a linear motor 8, and a displacement control device. The pressure control system includes a cylinder valve 12, a pressure medium, an external medium compressor 30, a vacuum pump 26, a detection and pressure reducing valve 32, a pressure gauge, and a safety relief device. The temperature control system includes a high-pressure container temperature control system and a pressure medium temperature control system. The concentration detection device includes a mass spectrometer 34, a pressure reducing valve, a pressure gauge, a shut-off valve, quick connectors, pipeline quick connectors, and a hose / metal pipe 14. The strain monitoring system includes a strain gauge 11, a high-pressure resistant sealed signal line connector structure 15, a signal line, an external signal line pipeline, and a strain processor 17. The safety system is a necessary safety protection structure or device to prevent injury to operators from the high-pressure container, hydrogen gas, etc.

[0044] The equipment connection relationship of the high-pressure resistance performance testing equipment and method for the inner liner of a hydrogen storage cylinder of the present invention is as follows: To facilitate the installation of the inner liner 4, the high-pressure container 1 is set up with multiple component units. The component units are connected by flanges, and the flanges are sealed by sealing rings or gaskets. They are also positioned and coaxially connected to each other through holes on the flanges. During service, the high-pressure container 1 is always kept sealed. The high-pressure container 1 is covered with a high-pressure container heating and cooling structure 2, which is used to control the temperature of the high-pressure container 1 and the temperature of the internal pressure medium. The heating and cooling structure 2 is covered with an insulation layer 3, which is used to insulate the high-pressure container 1. The inner liner 4 is installed in the high-pressure container 1 for testing. The inner holes for installing the bottle valve 12 and the BOSS displacement rod 6 are designed at the axis position of the end cap of the high-pressure container 1. The BOSS displacement rod 6 is installed at the axis position of the right end cap of the high-pressure container 1. The cylindrical surface of the BOSS displacement rod 6 is sealed to the high-pressure container 1 by a sealing ring, and can rotate relative to it and slide axially. The part of the BOSS displacement rod 6 exposed in the high-pressure container 1 is connected to a linear motor 8, and the axial displacement of the BOSS displacement rod 6 is controlled by a control system. A hydrogen concentration sensor 7 is installed at the outlet of the BOSS displacement rod 6 and the high-pressure vessel 1 to monitor for leaks. The BOSS displacement rod 6 is internally connected to the BOSS support rod 5 via threads. The BOSS support rod 5 supports the inner liner 4 and is coaxially connected to the positioning hole on the right side of the BOSS structure 402 of the inner liner; the BOSS support rod 5 is slidably connected to the high-pressure vessel 1 via a polygonal column. A bottle valve 12 is installed at the axis of the left end cap of the high-pressure vessel 1. The bottle valve 12 is threadedly connected to the left side of the BOSS structure 401 of the inner liner. After the connection is completed, the bottle valve 12 is fixed to the high-pressure vessel 1 with bolts and a flange; the bottle valve 12 and the high-pressure vessel 1 are sealed by a sealing ring. A pipe communicating with the inner liner 4 is located at the axis of the bottle valve 12, and is sealed to the inner liner 4 by a sealing structure used in actual use; other locations on the bottle valve 12 are respectively equipped with a high-pressure vessel ventilation pipe 1201 for venting into the high-pressure vessel 1 and a concentration detection pipe 1202. In addition, a signal line pipe 1203 is designed for installing signal lines. An air extraction device 16 is provided on the outer end face of the bottle valve 12 to prevent gas leakage at the bottle opening from causing danger.

[0045] like Figure 2As shown, the external wiring and piping corresponding to the position of the cylinder valve 12 are as follows: the signal line piping 1203 on the cylinder valve 12 is internally connected to the strain gauge 11, etc., and externally connected to the strain processor 17. The piping on the cylinder valve 12 that connects to the inside of the inner liner 4 is connected to the first pressure gauge 18, the inner liner stop valve 19, the inner liner pressurization stop valve 20, and the inner liner hydrogen / liquid compressor 21, respectively, starting from the cylinder valve 12. Among them, the inner liner medium heating and cooling system 22 is installed on the piping between the first pressure gauge 18 and the cylinder valve 12, mainly used to control the temperature of the medium entering the inner liner. The inner liner stop valve 19 and the inner liner pressurization stop valve 20 are connected externally to the inner liner evacuation stop valve 25 and the vacuum pump 26 through branch piping. In addition, the inner liner stop valve 19 and the inner liner pressurization stop valve 20 are connected to the high-pressure vessel venting piping 1201 on the cylinder valve 12 through branch piping, the high-pressure vessel pressure reducing valve 23, the high-pressure vessel stop valve 24. A high-pressure vessel medium heating and cooling system 27 is installed on the pipeline between the high-pressure vessel shut-off valve 24 and the bottle valve 12. A second pressure gauge 28, an external high-pressure vessel medium shut-off valve 29, and an external medium compressor 30 are connected externally via branch pipelines on the pipeline between the high-pressure vessel shut-off valve 24 and the high-pressure vessel medium heating and cooling system 27. A concentration detection pipeline 1202 on the bottle valve 12 is connected externally to a detection shut-off valve 31, a detection pressure reducing valve 32, a third pressure gauge 33, and a mass spectrometer 34.

[0046] The detection method of the present invention includes the following steps:

[0047] First, connect the inner liner 4 to the bottle valve 12 and fix the bottle valve 12 on the pressure vessel 1; the other end of the inner liner 4 is connected through the BOSS support rod 5 of the inner liner 4, and connected and sealed to the BOSS displacement rod 6. In addition, if it is necessary to attach strain gauges 11 to the inner liner, the strain gauges 11 and other detection materials should be attached to the location to be detected at this time, and the relevant signal lines are connected to the outside through the signal line conduit 1203 on the bottle valve.

[0048] The second step is to check that the inner liner 4 is correctly connected in the high-pressure container 1, then seal the high-pressure container 1 and check the sealing performance. Driven by the linear motor 8, the BOSS displacement rod 6 can control the displacement of the BOSS structure 402 on the right side of the inner liner 4 according to the pressure inside the inner liner 4, achieving a displacement consistent with the actual pressurization of the hydrogen storage cylinder.

[0049] The third step is to remove impurities. First, based on the specific testing requirements, determine whether it is necessary to remove air from the high-pressure container 1 and the inner liner 4. If so, first open the high-pressure container shut-off valve 24, the inner liner evacuation shut-off valve 25, and the vacuum pump 26 to evacuate the high-pressure container 1. After completion, close the high-pressure container shut-off valve 24, open the inner liner shut-off valve 19, and evacuate the inside of the inner liner 4. After both the high-pressure container 1 and the inner liner 4 have been evacuated, close the inner liner shut-off valve 19, the inner liner evacuation shut-off valve 25, and the vacuum pump 26.

[0050] The fourth step involves service pressure testing, leakage testing, and ambient temperature cracking testing. The basic pressurization operation for these three tests is consistent; the medium temperature is controlled according to requirements via the inner liner medium heating and cooling system 22, the high-pressure vessel medium heating and cooling system 27, and the high-pressure vessel heating and cooling structure 2. When pressurizing the inner liner 4, it is also necessary to simultaneously pressurize the high-pressure vessel 1. Simultaneously, the internal and external pressure difference required to induce the same deformation in the inner liner 4 can be calculated based on the approximate deformation of the hydrogen storage cylinder under high-pressure conditions, and the relevant parameters of the high-pressure vessel pressure reducing valve 23 can be set. Furthermore, when it is necessary to test the performance of the inner liner under large deformation conditions, the linear motor 8 can be used to control the axial displacement of the BOSS structure 402 on the right side of the inner liner to match the actual situation, based on the approximate axial strain of the hydrogen storage cylinder.

[0051] When conducting hydraulic or hydrogen-related tests, open the inner tank hydrogen / liquid compressor 21, inner tank shut-off valve 19, inner tank pressurization shut-off valve 20, and high-pressure vessel shut-off valve 24. The test medium is then introduced into the inner tank 4 and high-pressure vessel 1 through the hydrogen / liquid compressor 21. After reaching the set pressure, the pressure is maintained for a certain period, and the deformation of the inner tank 4 is detected as required. After completion, close the inner tank pressurization shut-off valve 20 and open the inner tank venting shut-off valve 25 to release pressure. After depressurization, remove the inner tank 4 and test its appearance and mechanical properties as required.

[0052] When a leak test is required, unlike the hydraulic test described above, instead of opening the high-pressure vessel shut-off valve 24, the external medium shut-off valve 29 of the high-pressure vessel is opened, and nitrogen or inert gas is introduced into the high-pressure vessel 1 through the external medium compressor 30. Furthermore, during the test, nitrogen or other inert gas is continuously introduced into the high-pressure vessel through the high-pressure vessel venting line 1201, and the detection shut-off valve 31 is opened, allowing the mixed gas in the high-pressure vessel 1 to be depressurized before entering the mass spectrometer 34 for analysis of the hydrogen content in the mixed gas. Other operations are the same as described above.

[0053] Step 5, Cyclic Testing. Cyclic testing involves repeating the process based on a single hydraulic or hydrogen test.

[0054] In this invention, the inner liner 4 can be a pre-developed inner liner, or, based on the target test location, only the target test location can be formed. For example... Figure 3 As shown, when only the sealing performance and stress-strain of the inner liner 4 sealing structure and metal-plastic connection structure are tested under ambient temperature and service pressure conditions, and the influence of changes in the overall structure of the inner liner is irrelevant, only the relevant local structures need to be molded to carry out the test.

[0055] In this invention, the inner liner 4 can be installed in the following ways: First, the inner liner 4 can be directly installed on the testing device to test its strain, permeability, leakage, and other behaviors under pressure conditions. Second, after the inner liner 4 is covered with a rigid shell 9, the deformation behavior, i.e., stress distribution, of the inner liner 4 under high pressure conditions and constrained by the outer layer material (simulating carbon fiber composite material) can be tested and evaluated more realistically, thus assisting in optimizing the structure of the inner liner 4. Third, furthermore, when casting the rigid shell 9, the inner liner 4 can be treated according to the carbon fiber curing process to evaluate its strain behavior during the curing process.

[0056] The external rigid shell 9 of this invention is preferably made of low-melting-point alloy or resin, and alternatively, it can be made of hard, easily malleable materials such as plaster. The rigid shell 9 cannot withstand high pressure. The manufacturing method of the rigid shell 9 is as follows: a suitable thickness is selected as the thickness of the rigid shell 9. Preferably, rigid foam is cut to form the outer shape of the rigid shell 9 as an outer mold, and the dimensional accuracy is set according to testing requirements. The rigid foam is wrapped around the outside of the inner liner 4, and gas at a certain pressure is filled into the inner liner 4 so that the inner liner 4 can serve as an inner mold. Resin or low-melting-point alloy is poured between the inner liner 4 and the rigid foam, and the rigid foam mold is removed after curing or cooling. Preferably, the rigid foam is designed as a segmented or modular casting mold. That is, the rigid foam is designed as two segments along the axis of the inner liner, or as segments such as a cylinder or end cap. The advantage of the rigid foam is that the model can be cut at will, the molding time is short, and the cost is low. Alternatively, the outer mold can be made of sand mold or other materials.

[0057] If it is necessary to accurately control the pressure difference between the inside and outside of the inner liner 4 during the test, that is, if it is not possible to accurately control the pressure inside the inner liner 4 and the pressure inside the high-pressure vessel 1, a recyclable outer rigid shell 9 should be manufactured on the outside of the inner liner 4.

[0058] Simultaneous filling of the inner liner 4 with pressurized medium from both inside and outside may cause the high-pressure medium outside the inner liner 4 to enter the gap between the inner liner 4 and the BOSS structure 401 on the left side of the inner liner, resulting in a discrepancy between the actual pressure difference and leakage at the sealing position and that of the hydrogen storage cylinder. Therefore, in this invention, the preferred testing method for the quality of the inner liner sealing structure is as follows: Figure 4 As shown, a high-pressure container 1 with a structure matching the inner liner 4 is manufactured. Based on the original testing equipment, epoxy resin, paraffin wax, or low-temperature alloys are injected into the gap between the inner liner 4 and the high-pressure container 1 through a circular hole in the bottle valve 12. After curing, a relatively tight contact between the inner liner 4 and the high-pressure container 1 can be achieved. At this point, it is no longer necessary to introduce high-pressure medium to the outside of the inner liner 4; only the inside of the inner liner 4 needs to be introduced to test its sealing performance and other properties.

[0059] As a further alternative location, such as Figure 5As shown, part of the structure of the high-pressure container 1 on the right side of the inner liner can be manufactured as a structure without the BOSS displacement rod 6 placement hole.

[0060] The high-pressure container ventilation line 1201 and concentration detection line 1202 on the bottle valve 12 of the present invention can be connected to a hose / metal tube 14 via a quick connector 13. The other end of the hose / metal tube 14 can be placed at the target inflation and deflation position in the high-pressure container 1.

[0061] In this invention, the strain gauge can be attached either inside the inner liner (if feasible) or outside the inner liner 4. The signal lines of the strain gauges inside the inner liner 4 or the high-pressure vessel 1 are connected to the external signal lines via the innovative high-pressure resistant signal line connector structure 15 of this invention.

[0062] like Figure 6 As shown, the high-pressure resistant sealed signal line connector structure 15 of the present invention employs sealing methods such as conical sealing and labyrinth sealing. Taking a representative structure as an example, from the outside to the inside of the high-pressure pipeline or high-pressure valve, the components are: signal line fixing plug 1504, gasket 1503, polymer material female connector 1502, polymer material male connector 1501, and high-pressure pipeline or high-pressure valve. The signal line fixing plug 1504 is threaded to the high-pressure pipeline and sealed with an end-face sealing ring. The signal line fixed in the polymer material male connector 1501 can be inserted into the signal line fixed in the polymer material female connector 1502. Under high pressure conditions, the polymer material is compressed, improving the sealing performance. Furthermore, since the polymer material cannot directly withstand high pressure differentials, the signal line conduit 1203 should be as small as possible, and a gasket 1503 should be used on the low-pressure side. The gasket 1503 is preferably made of ceramic or metal material, and the gasket 1503 is isolated from the signal line by an insulating material.

[0063] The conductive interface between the polymer material female connector 1502 and the polymer material male connector 1501 uses an interference fit. Preferably, as shown in the detailed drawing, at the mating position of the female connector 1502 and male connector 1501, the female connector is suspended inside and out to prevent deformation of the female connector due to high pressure, which could affect signal transmission. The polymer material female connector 1502 and polymer material male connector 1501 are preferably formed using high-pressure molding methods such as injection molding or compression molding to improve the density of the material. The polymer material on the polymer material female connector 1502 and polymer material male connector 1501 can be selected from elastic materials such as rubber or nylon elastomer. Alternatively, in the signal line conduit 1203 of the bottle valve 12, a reactive nylon elastomer can be injected for sealing. The nylon elastomer is manufactured by reaction molding or injection molding. After molding, the elastomer shrinks and tightly wraps the conduit, and is compressed under high pressure. Furthermore, a longer sealing path can improve sealing performance and reduce leakage.

[0064] As an alternative structural solution for the high-pressure resistant sealed signal line connector structure 15, such as Figure 7 As shown, the original signal line fixing plug 15 is split into an outer signal line fixing plug 15041 and an inner signal line fixing plug 15042, and is locked and compacted by screws 15043 to the alternative polymer material female connector 15021. The alternative polymer material female connector 15021 is formed by injection molding or other methods, wherein the polymer material is an elastomer material, and the metal signal line is coated with an insulating coating to achieve gas sealing and signal insulation. Alternatively, the two signal lines on the strain gauge can use high-pressure resistant sealed signal line connector structures 15 separately instead of being integrated into the same connector structure.

[0065] In this invention, when there are many signal lines, such as Figure 8 As shown, the bottle valve signal line 1203 can also use an external signal line 1204 to prevent the cross-sectional area of ​​the polymer material female connector 1502 and the polymer material male connector 1501 from being too large, which could lead to sealing failure. Furthermore, using the external signal line 1204 allows for simultaneous control of the internal pressure of the high-pressure vessel 1 or the inner liner 4, while simultaneously acquiring detection data. The external signal line 1204 includes a connector 12041 that can connect to the signal line 1203 on the bottle valve 12. Multiple signal lines 1203 can be connected to the connector simultaneously, enabling the simultaneous transmission of multiple signals. The connector 12041 is threadedly sealed to the through hole of the original signal line 1203 on the bottle valve 12 via its external threaded head 120411, thereby fixing the connector 12041 onto the bottle valve 12. Then, each signal line conduit 1203 on the connector 12041 passes through the through hole in the connector 12041 to extend into the interior of the high-pressure vessel 1, thereby realizing signal transmission.

[0066] The hydrogen storage cylinder liner described in this invention is not limited to hydrogen storage and transportation, but is also applicable to other high-pressure gaseous storage fields such as oxygen, helium, and argon.

[0067] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-pressure resistance testing device for the inner liner of a hydrogen storage cylinder, characterized in that: The system includes a high-pressure vessel, a BOSS displacement control system, a pressure control system, a temperature control system, a concentration detection device, and a safety system. The high-pressure vessel is a high-pressure resistant, explosion-proof container made of metal or composite material winding. All components of the high-pressure vessel are connected by flanges, which are sealed with sealing rings or gaskets and positioned by a positioning structure. During service, the high-pressure vessel remains sealed. An external heating and cooling system is provided to control the temperature of the high-pressure vessel and the internal pressure medium. An insulation layer is also provided around the heating and cooling system. An inner liner is installed within the high-pressure vessel for testing. The vessel's end caps have internal holes for installing a bottle valve and a BOSS displacement rod. A BOSS displacement rod is installed on the right end cap. The cylindrical surface of the BOSS displacement rod is sealed to the high-pressure vessel by a sealing ring and can slide relative to it and move axially. The portion of the BOSS displacement rod protruding from the high-pressure vessel is connected to a linear motor, and the BOSS displacement rod is controlled by the control system. The axial displacement of the BOSS displacement rod is monitored by a hydrogen concentration sensor installed at the outlet of the high-pressure vessel to detect leaks. The BOSS displacement rod is threadedly connected to the BOSS support rod inside the vessel. The BOSS support rod is used to support the inner liner and is fixedly connected to the BOSS structure of the inner liner. The BOSS support rod is slidably connected to the high-pressure vessel via a polygonal column. A bottle valve is installed at the axis position of the left end cap of the high-pressure vessel. The bottle valve is threadedly connected to the left BOSS of the inner liner. After the connection is completed, the bottle valve is bolted to the high-pressure vessel. The bottle valve and the high-pressure vessel are sealed by a sealing ring. A pipeline connected to the inner liner is provided at the axis position of the bottle valve, and it is sealed to the inner liner through a sealing structure used in actual use. Other positions of the bottle valve are respectively provided with a high-pressure vessel ventilation pipeline for venting into the high-pressure vessel and a concentration detection pipeline. An air extraction device is provided at the outer end face of the bottle valve. A high-pressure resistant sealed signal line connector structure and related extension structures are also provided at the bottle valve to realize wired signal transmission between high pressure and low pressure.

2. The high-pressure resistance testing equipment for the inner liner of a hydrogen storage cylinder according to claim 1, characterized in that: The high-pressure resistant sealed signal line connector structure employs a conical seal and a labyrinth seal. From the outside to the inside of the high-pressure pipeline or valve, the high-pressure resistant sealed signal line connector structure consists of a signal line fixing plug, a gasket, a polymer female connector, a polymer male connector, and the high-pressure pipeline or valve. The signal line fixing plug is threaded to the high-pressure pipeline and sealed with an end-face sealing ring. The signal line fixed in the polymer male connector can be inserted into the signal line fixed in the polymer female connector, and a gasket is provided on the left side of the polymer female connector. The gasket is made of ceramic. It may be made of metal material, and the gasket and signal line are isolated by insulating material; the conductive interface between the polymer material female connector and the polymer material male connector uses an interference fit; at the mating position of the polymer material female connector and the polymer material male connector, the polymer material female connector is suspended inside and outside to prevent high voltage from deforming the polymer material female connector and affecting signal transmission; the polymer material female connector and the polymer material male connector are injection molded or compression molded; the polymer material is rubber material or nylon elastomer material; in the bottle valve signal line pipeline, reactive nylon elastomer is injected for sealing.

3. The high-pressure resistance testing equipment for the inner liner of a hydrogen storage cylinder according to claim 1, characterized in that: When there are many signal lines, the bottle valve signal line pipeline uses an external signal line pipeline to prevent the cross-sectional area of ​​the polymer material female connector and the polymer material male connector from being too large, which would lead to sealing failure.

4. The high-pressure resistance testing equipment for the inner liner of a hydrogen storage cylinder according to claim 1, characterized in that: The testing equipment also includes an external rigid shell, which is made of a low-melting-point alloy, resin, or plaster. The manufacturing method of the external rigid shell is as follows: select a suitable thickness as the thickness of the external rigid shell; use rigid foam to cut out the shape of the external rigid shell as an outer mold, and set the dimensional accuracy according to the testing requirements. An outer mold is wrapped around the outside of the inner liner, and the inner liner is filled with gas at a certain pressure to make the inner liner serve as the inner mold. Resin or a low-melting-point alloy is poured between the inner liner and the outer mold, and the outer mold is removed after curing or cooling. The rigid foam is preferably designed as a segmented or segmented combination to form the outer mold. That is, the rigid foam is designed as two segments along the axis of the inner liner, or as a cylinder or end cap. The outer mold can be made of sand mold or other materials.

5. The high-pressure resistance testing equipment for the inner liner of a hydrogen storage cylinder according to claim 1, characterized in that: The high-pressure container's venting pipeline and concentration detection pipeline are connected to a flexible hose or metal pipe via quick-connect fittings. The other end of the flexible hose or metal pipe is placed at the target inflation and deflation position within the high-pressure container.

6. The high-pressure resistance testing equipment for the inner liner of a hydrogen storage cylinder according to claim 1, characterized in that: By applying high pressure simultaneously inside and outside the inner liner, controlling the temperature of the pressure medium, and controlling the axial movement of the BOSS structure on the right side of the inner liner according to the pressure of the medium, the service performance of the non-pressure-bearing inner liner under high pressure conditions can be directly tested.

7. A testing method, wherein the testing method applies the high-pressure resistance performance testing equipment for the inner liner of a hydrogen storage cylinder as described in claim 1, characterized in that, Includes the following steps: The first step is to connect the inner liner to the bottle valve and fix the bottle valve on the pressure vessel; the other end of the inner liner is connected through the inner liner support rod and connected to the BOSS displacement rod and sealed; in addition, if it is necessary to attach strain gauges to the inner liner, attach the strain gauges at the positions to be tested, and connect the relevant signal lines to the outside through the signal line pipeline on the bottle valve. The second step is to check that the inner liner is connected correctly in the high-pressure container, then seal the high-pressure container and check the sealing performance. The BOSS displacement rod, driven by a linear motor, controls the displacement of the BOSS structure on the right side of the inner liner according to the pressure inside the inner liner, so as to achieve the same displacement as the actual hydrogen storage bottle when pressurized. The third step is to clean impurities. First, based on the specific testing requirements, determine whether it is necessary to clean the air in the high-pressure container and the inner liner. If so, first open the high-pressure container shut-off valve, the inner liner evacuation shut-off valve, and the vacuum pump to evacuate the high-pressure container. After that, close the high-pressure container shut-off valve, open the inner liner shut-off valve, and evacuate the inside of the inner liner. After both the high-pressure container and the inside of the inner liner have been evacuated, close the inner liner shut-off valve, the inner liner evacuation shut-off valve, and the vacuum pump. The fourth step involves service pressure testing, leakage testing, and ambient temperature cracking testing. The basic pressurization operation for these three tests is consistent. The medium temperature is controlled according to requirements through the inner liner medium heating and cooling system, the high-pressure vessel medium heating and cooling system, and the high-pressure vessel heating and cooling structure. When pressurizing the inner liner, it is also necessary to pressurize the high-pressure vessel simultaneously. At the same time, based on the approximate deformation of the hydrogen storage cylinder under high pressure conditions, the internal and external pressure difference required to cause the inner liner to undergo the same deformation is calculated, and the relevant parameters of the high-pressure vessel pressure reducing valve are set. In addition, when it is necessary to test the performance of the inner liner under large deformation conditions, based on the approximate axial strain of the hydrogen storage tank, the BOSS structure on the right side of the inner liner is controlled by a linear motor to move axially to match the actual situation. When conducting hydraulic or hydrogen-related tests, open the inner tank hydrogen / liquid compressor, inner tank shut-off valve, inner tank pressurization shut-off valve, and high-pressure vessel shut-off valve. Fill the inner tank and high-pressure vessel with the test medium through the hydrogen / liquid compressor. After reaching the set pressure, maintain the pressure for a certain period and check the inner tank deformation as required. After completion, close the inner tank pressurization shut-off valve and open the inner tank vent shut-off valve to release pressure. After depressurization, remove the inner tank and check the changes in its appearance and mechanical properties as required. When a leak test is required, unlike the hydraulic test described above, the high-pressure vessel shut-off valve is not opened. Instead, the external medium shut-off valve of the high-pressure vessel is opened, and nitrogen or inert gas is introduced into the high-pressure vessel through an external medium compressor. During the test, nitrogen or other inert gas is continuously introduced into the high-pressure vessel through the high-pressure vessel venting line, and the test shut-off valve is opened to depressurize the mixed gas in the high-pressure vessel before it enters the mass spectrometer to analyze the hydrogen content in the mixed gas. Other operations are the same as described above. The fifth step is the cyclic test; the cyclic test is a repeated operation based on a single hydraulic or hydrogen test.

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