KR102536814B1 - Boss for high pressure hydrogen gas storage tank and its manufacturing method - Google Patents

Abstract

The present invention is made in the form of a tube having a hollow penetrating upward and downward, preparing a boss base member provided with a protrusion extending in a radial direction on the lower side, on the surface of the protrusion of the boss base member with respect to the central axis of the boss base member A boss for a high-pressure hydrogen storage container comprising the steps of forming a plurality of concentric grooves, coating the surface of the protruding part of the boss base member, and bonding a synthetic resin liner to the surface of the protruding part of the boss base member by injection molding. A manufacturing method is provided.

Description

Boss for high pressure hydrogen gas storage tank and its manufacturing method

The present invention relates to a boss for a high-pressure hydrogen storage container joined to a storage container for storing high-pressure hydrogen gas and a manufacturing method thereof.

In general, when a general metal hydrogen storage container used to store high-pressure hydrogen gas is charged at 700 bar or more, corrosion occurs on the inner surface in direct contact with the gas, making it difficult to use it as a storage container for a fuel cell vehicle for a long time.

In order to solve this problem, a synthetic resin (plastic) is used to separately manufacture a liner mounted inside the storage container, and the outside is reinforced with glass or carbon fiber in a method such as filament winding to cope with high pressure. In such a composite high-pressure container, in particular, by using a plastic liner, it is possible to cope with extreme changes in pressure and temperature due to repetitive gas filling/discharging.

However, the boss bonded to the plastic liner is made of a metal material because it must be directly coupled to devices such as a gas pressure meter, a pressure regulator, and a receptacle (gas injector). When bonding a metal boss and a plastic liner, a separation phenomenon occurs over time due to the unique physical and chemical characteristics of each material. Also, the size of the plastic liner is determined according to the storage amount of the high-pressure gas, and direct bonding between the plastic liner and the boss is practically difficult due to its shape and volume.

Therefore, using the same material as the plastic liner on the outer surface of the boss, a plastic film of arbitrary thickness is first formed by the insert injection molding method, and then the lower surface of the boss and the upper surface of the separately manufactured plastic liner are finally bonded by the thermal fusion method. to complete the plastic liner.

However, the conventional boss has a problem in that gas or fluid leaks in the storage container as the interface between the boss and the plastic membrane is separated in a high-temperature and high-pressure storage container environment during long-term use.

A related technology for such a boss for a high-pressure container is presented in Korean Patent Registration No. 10-0469636 (February 2, 2005).

An object of the present invention is to provide a boss for a high-pressure hydrogen storage container and a method for manufacturing the same, which can prevent leakage of gas or fluid while stably maintaining bonding force with a plastic film even in a high-temperature and high-pressure environment repeated for a long time.

The present invention is made in the form of a tube having a hollow through the upper and lower sides, preparing a boss base member having a protrusion extending in a radial direction on the lower side, on the surface of the protrusion of the boss base member on the central axis of the boss base member For a high-pressure hydrogen storage container comprising the steps of forming a plurality of concentric grooves on the surface of the boss base member, coating the surface of the protruding portion of the boss base member, and bonding a synthetic resin liner to the surface of the protruding portion of the boss base member by injection molding. A method for manufacturing a boss is provided.

In addition, in the step of preparing the boss base member having a tubular shape having a hollow through the upper and lower sides and having a protrusion extending in a radial direction on the lower side, the thickness of the protrusion portion in which the groove of the boss base member is formed is determined in advance. It can be formed to be thicker by 30 to 50% of the groove depth than the set design value.

In addition, in the step of forming a plurality of grooves on the surface of the protrusion of the boss base member, the central axis of the groove is formed to form an inclined angle of 15 to 30 degrees with the central axis of the boss base member, and a pair of adjacent grooves may be formed such that the inclination angle directions are opposite to each other.

In addition, the step of forming wall portions concentrically with respect to the central axis of the boss base member on both sides of the surface of the protruding portion of the boss base member, the height of the wall portion may be formed to 50 to 100% of the depth of the groove.

In addition, after the wall portions are provided on both sides of the surface of the protruding portion around the groove, a pair of adjacent wall portions may be bent while pressing the wall portion so that the wall portions are disposed adjacent to each other around the groove.

In addition, the step of coating the surface of the protruding part of the boss base member is the step of treating the surface of the protruding part of the boss base member with an oxide film, and the surface of the protruding part of the boss base member treated with an oxide film is treated with TTN (6-mercapto-1, 3,5-triazine-2,4-dithiol) may include a step of film treatment with a compound.

In addition, the boss base member may be made of aluminum alloy, and the synthetic resin liner may be made of polyamide (PA) or polyphenylene sulfide (PPS).

A boss for a high-pressure hydrogen storage container and a manufacturing method thereof according to the present invention, after forming grooves on the surface of the protruding portion of the boss base member, film treatment is performed on the surface of the protruding portion. Then, when bonding the synthetic resin liner to the surface of the protrusion, the bond area and physical bonding force with the synthetic resin liner is increased through the coated portion of the surface of the protrusion and the groove, and the non-periodic pressure in the state installed inside the high-pressure gas storage container And it is possible to prevent the leakage of gas or fluid in the high-pressure gas storage container by preventing separation of the synthetic resin liner even when the temperature changes.

1 is a flowchart illustrating a method of manufacturing a boss for a high-pressure hydrogen storage container according to an embodiment of the present invention.
2 is a plan view of the boss base member processed through steps S100 and S110 shown in FIG. 1 .
Figure 3 is a cross-sectional view showing the shape of the groove of the boss base member processed by step S110 shown in Figure 1.
FIG. 4 is an image of a surface photographed with a scanning electron microscope (SEM) of the oxide film shape of the boss base member through step S120 shown in FIG. 1 .
FIG. 5 is an image obtained by measuring the film thickness by SEM cross-sectional imaging after anodizing the boss base member through step S120 shown in FIG. 1 .
FIG. 6 is an image obtained by measuring the oxide film and TTN film thickness by HAADF-STEM (High-Angle Annular Dark-Field/Scanning Transmission Electron Microscope) cross-section of the surface of the boss base member through step S120 shown in FIG. 1.
FIG. 7 is a state diagram in which a synthetic resin liner is bonded to a boss base member through step S130 shown in FIG. 1 .
8 is a perspective view of a boss manufactured through a method for manufacturing a boss for a high-pressure hydrogen storage container according to an embodiment of the present invention.
9 is a diagram showing the installation state of the high-pressure hydrogen storage container of the boss manufactured through the manufacturing method of the boss for the high-pressure hydrogen storage container according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart illustrating a method of manufacturing a boss for a high-pressure hydrogen storage container according to an embodiment of the present invention. Referring to FIG. 1, in the method of manufacturing a boss for a high-pressure hydrogen storage container according to an embodiment, a step of preparing a boss base member 100 (S100), a plurality of projections 102 on the surface of the boss base member 100 Forming the groove 140 of (S110), film-processing the surface of the protrusion 102 of the boss base member 100 (S120), synthetic resin liner on the surface of the protrusion 102 of the boss base member 100 ( 160) is included (S130).

First, looking at the step of preparing the boss base member 100 (S100), as shown in FIG. 2, a tubular head having a hollow 104 penetrated vertically by forging a cylindrical aluminum alloy material at room temperature While the portion 101 and the lower outer circumferential surface of the head portion 101 are provided with protrusions 102 extending in the radial direction, the overall boss shape is formed. Here, the boss base member 100 uses an aluminum alloy of the 6061 series, and more specifically, 6061-T6 may be used.

At this time, the internal stress generated in the boss base member 100 during molding may be removed through a generally applied heat treatment process. In addition, the thickness of the protrusion 102 of the boss base member 100, more specifically, the thickness of the protrusion 102 on which the groove 140 is formed is greater than the thickness of the protrusion 102 on which the groove 140 is not formed. form thick. That is, the thickness of the portion of the protrusion 102 in which the groove 140 of the boss base member 100 is formed is about the bottom surface 103 of the initially preset protrusion 102, as shown in (a) and (b) of FIG. It is formed to be thicker than the design value by about 30 to 50% of the depth of the groove 140 to be formed later, so that the wall portion 142 is stably formed when the groove 140 is formed.

In this way, after preparing the boss base member 100, as shown in FIG. 2, a plurality of grooves ( 140) is formed (S110). When the groove 140 is formed on the bottom surface 103 of the protrusion 120 of the boss base member 100, a plurality of grooves 140 are spaced apart from each other in a concentric circle with respect to the central axis of the boss base member 100. Here, the groove 140 may be formed using an automated machine such as multi-axis CNC (Computer Numerical Control).

And, as shown in (c) of FIG. 3, when the groove 140 is formed on the bottom surface 103 of the protrusion 102 provided on the boss base member 100, the central axis of the groove 140 is the boss base member ( 100) may be formed to form an inclined angle of 15 to 30 degrees with the central axis. In addition, a pair of grooves 140 adjacent to each other are formed so that the inclination angle directions are opposite to each other, and then when the synthetic resin liner 160 is bonded to the surface of the protrusion 102 of the boss base member 100, the groove 140 While the synthetic resin liner 160 inserted into the interlocking coupling is made, the bonding strength between the surface of the protrusion 102 and the synthetic resin liner 160 is increased.

In addition, as shown in (a) of FIG. 3, in the step of forming a plurality of grooves 140 on the surface of the protrusion 102 of the boss base member 100, both sides of the surface of the protrusion 102 based on the groove 140 A wall portion 142 may be additionally formed concentrically with respect to the central axis of the boss base member 100. Here, when the synthetic resin liner 160 is bonded to the surface of the protrusion 102 of the boss base member 100, the wall portion 142 increases the bonding area between the surface of the protrusion 102 and the synthetic resin liner 160, and the protrusion 102 The bonding strength between the surface and the synthetic resin liner 160 is increased. Here, the height 142a of the wall portion 142 may be 50 to 100% of the depth of the groove 140 . At this time, when the height 142a of the wall portion 142 is formed to be less than 50% of the depth of the groove 140, when bending is formed by pressing the wall portion 142 thereafter, it is difficult to stably perform bending molding and synthetic resin There is a limit to stably providing the bonding area of the liner 160 . Conversely, when the height 142a of the wall portion 142 exceeds 100% of the depth of the groove 140, the wall portion 142 may be damaged during bending by pressing the wall portion 142. At this time, the wall portion 142 may be formed by machining additional grooves 140a on both sides of the groove 140 .

In this way, after the wall portion 142 is provided on both sides of the surface of the protruding portion 102 based on the groove 140, a pair of adjacent to each other around the groove 140 as shown in (b) of FIG. The wall portion 142 may be bent and molded 144 while pressing the wall portion 142 so that they are disposed adjacent to each other. Here, when the pair of wall parts 142 adjacent to each other are disposed adjacent to each other, when the synthetic resin liner 160 is bonded to the surface of the protruding part 102 of the boss base member 100, the synthetic resin inserted into the groove 140 The bonding strength between the surface of the protrusion 102 and the synthetic resin liner 160 is increased while the wall portion 142 of the liner 160 is engaged.

After forming the wall portion 142 in FIGS. 3 (a) and (b) described above, the bending of the wall portion 142 is pressurized with a press or a roller to lower the height of the wall portion 142 to a pressurized state while adjacent to each other A pair of wall parts 142 may be arranged adjacent to each other, and in another method, a pair of wall parts 142 adjacent to each other may be grooved using an automated machine such as CNC to have a shape arranged adjacent to each other. Of course, (140, 140a) may be formed. Here, reference numeral 103 denotes the bottom surface of the protrusion 102 of the boss base member 100 according to the initially set design value thickness.

In this way, after the grooves 140 and 140a are formed on the surface of the protrusion 102 of the boss base member 100, the surface of the protrusion 102 of the boss base member 100 is treated with a film. The film treatment of the surface of the protruding part 102 of the boss base member 100 then increases the bonding area with the synthetic resin liner 160 to increase the bonding strength between the synthetic resin liner 160 and the surface of the protruding part 102. . 4 to 6, the coating treatment on the surface of the protruding portion 102 of the boss base member 100 is performed on the surface of the protruding portion 102 of the boss base member 100 by anodizing films 150, 150a, 150b, and 150c. , 150d) processing step, the surface of the protrusion 102 of the boss base member 100 treated with anodized oxide films (150, 150a, 150b, 150c, 150d) TTN (6-mercapto-1,3,5-triazine-2 , 4-dithiol) including the step of film treatment (152) with a compound. Here, FIG. 4 is a photograph of the surface of the oxide film (150, 150a, 150b, 150c, 150d) formed after anodizing the surface of the protrusion 102 of the boss base member 100 with a scanning electron microscope (SEM). 5 is an image of the film thickness measured by SEM cross-sectional imaging after anodizing the surface of the boss base member 100, and FIG. 6 is a boss base member treated with a general anodized aluminum alloy (100 ) in HAADF-STEM (High-Angle Annular Dark-Field/Scanning Transmission Electron Microscope) cross-sectional imaging after additionally treating TTN (6-mercapto-1,3,5-triazine-2,4-dithiol) film on the surface This is an image of the thickness of the oxide film and TTN film measured by

At this time, after the surface of the protrusion 102 of the boss base member 100 is treated with an anodized film (150, 150a, 150b, 150c, 150d), the boss base treated with anodized film (150, 150a, 150b, 150c, 150d) The method of coating the surface of the protrusion 102 of the member 100 with a TTN (6-mercapto-1,3,5-triazine-2,4-dithiol)-based compound (152) is TT (1,3,5- A method of electrolytic polymerization using aluminum and SUS electrodes in an aqueous solution of nitrous acid mixed with triazine-2,4,6-trithiol or DB (6-dibutylamino-1,3,5-triazine-2,4-dithiol) at a certain temperature can be used.

In this way, after the film treatment on the surface of the protrusion 102 of the boss base member 100 is completed, as shown in FIG. 7, a synthetic resin liner 160 is applied to the surface of the protrusion 102 of the boss base member 100 by injection molding. To be joined (S130). At this time, the method of bonding the synthetic resin liner 160 to the surface of the protrusion 102 of the boss base member 100 is the boss base member 100 subjected to surface coating treatment through high-pressure injection of the melted synthetic resin in the synthetic resin molding equipment. A film having a certain thickness is formed on the surface of the protrusion 102 . At this time, injection molding is recommended within a short time after the surface coating treatment in order to minimize the degradation of the coating on the surface of the protruding portion 102 of the boss base member 100, preferably not exceeding 120 hours. In addition, the synthetic resin liner 160 may be made of PA (Polyamide) or PPS (Polyphenylene sulfide) material, and more specifically, PA6 nylon may be selected and used.

The boss manufactured through the manufacturing method of the boss for the high-pressure hydrogen storage container of one embodiment is synthetic resin in a state where grooves 140 are formed and coated on the surface of the protrusion 102 of the boss base member 100, as shown in FIG. The liner 160 is bonded. In addition, as shown in FIG. 9, a separate plastic liner bonded to the high-pressure gas storage container 10 is combined in a state of being installed in the high-pressure gas storage container 10.

As such, in the boss for a high-pressure hydrogen storage container and a manufacturing method thereof according to an embodiment, after forming grooves 140 on the surface of the protrusion 102 of the boss base member 100, the surface of the protrusion 102 is treated with a film. do Thereafter, when the synthetic resin liner 160 is bonded to the surface of the protrusion 102, the joint area with the synthetic resin liner 160 is increased and the physical bonding force is increased through the groove 140 and the film-treated portion of the surface of the protrusion 102 Bar, in a state installed inside the high-pressure gas storage container 10, the separation of the synthetic resin liner 160 is prevented even with non-periodic pressure and temperature changes to prevent leakage of gas or fluid in the high-pressure gas storage container 10 do.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is only exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

100: boss base member 101: head
102: protrusion 103: bottom surface
104: hollow 140, 140a: groove
142: wall part 142a: wall height
150, 150a, 150b, 150c, 150d: oxide film 152: TTN film
160: synthetic resin liner

Claims (8)

preparing a boss base member formed in a tubular shape having a hollow penetrating upward and downward, and having a protrusion extending in a radial direction at a lower side;
Forming a plurality of concentric grooves on the surface of the protrusion of the boss base member with respect to the central axis of the boss base member;
coating the surface of the protrusion of the boss base member;
Bonding a synthetic resin liner to the surface of the protrusion of the boss base member by injection molding; includes,
In the step of forming a plurality of grooves on the surface of the protrusion of the boss base member, the step of forming wall portions concentrically with respect to the central axis of the boss base member on both sides of the surface of the protrusion of the boss base member, wherein the wall The height of the part is formed from 50 to 100% of the depth of the groove,
After the wall parts are formed on both sides of the surface of the protruding part around the groove, the boss for the high-pressure hydrogen storage container is bent while pressing the wall so that the pair of adjacent wall parts are disposed adjacent to each other around the groove. manufacturing method. The method of claim 1,
The step of preparing a boss base member having a tubular shape having a hollow penetrating upward and downward and having a protrusion extending in a radial direction on the lower side,
The method of manufacturing a boss for a high-pressure hydrogen storage container formed so that the thickness of the protruding portion where the groove of the boss base member is formed is about 30 to 50% thicker than the preset design value of the groove depth. The method of claim 1,
Forming a plurality of grooves on the surface of the protrusion of the boss base member,
The central axis of the groove is formed to form an inclined angle of 15 to 30 degrees with the central axis of the boss base member,
A method of manufacturing a boss for a high-pressure hydrogen storage container in which a pair of grooves adjacent to each other are formed so that the inclination angle directions are opposite to each other. The method of claim 1,
The step of coating the surface of the protrusion of the boss base member,
Oxidizing the surface of the protrusion of the boss base member;
Manufacture of a boss for a high pressure hydrogen storage container comprising the step of coating the surface of the protruding part of the boss base member treated with an oxide film with a TTN (6-mercapto-1,3,5-triazine-2,4-dithiol)-based compound method. The method of claim 1,
The boss base member is made of aluminum alloy,
The synthetic resin liner is a method for manufacturing a boss for a high-pressure hydrogen storage container made of PA (Polyamide) or PPS (Polyphenylene sulfide) material. A boss for a high-pressure hydrogen storage container manufactured by the manufacturing method of any one of claims 1 to 5.
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