JP6153085B2 - Manufacturing method of high-pressure tank - Google Patents

Description

  The present invention relates to a method for manufacturing a high-pressure tank in which a fiber reinforcing layer is formed on a liner.

  In recent years, development of vehicles driven by combustion energy of fuel gas or electric energy generated by an electrochemical reaction of fuel gas has progressed. A vehicle may be equipped with a high-pressure tank that stores fuel gas such as natural gas or hydrogen. For this reason, the high-pressure tank is required to be lightweight, and FRP (Fiber) in which a hollow liner is covered with carbon fiber reinforced plastic or glass fiber reinforced plastic (hereinafter collectively referred to as a fiber reinforced resin layer). The adoption of high-pressure tanks (hereinafter simply referred to as high-pressure tanks) made of Reinforced Plastics (fiber reinforced plastics) is advancing. As the liner, a resin-made hollow container is usually used from the viewpoint of weight reduction.

  In manufacturing such a high-pressure tank, a filament winding method (hereinafter referred to as FW method) is adopted, and by this FW method, fibers impregnated with a thermosetting resin such as an epoxy resin are repeatedly wound around the outer periphery of the liner to obtain a fiber reinforced resin. A layer is formed on the liner. After the resin layer is formed, the thermosetting resin contained in the resin layer is thermoset to manufacture a high-pressure tank in which the liner is covered and reinforced with the fiber reinforced resin layer.

  In such a high-pressure tank in which the liner is reinforced with the fiber reinforced resin layer formed by the FW method, there is no gap between the outer surface of the liner and the layer close to the outer surface as well as the fiber reinforced resin layer. Is desirable from the viewpoint of ensuring strength.

  However, when the liner and the fiber reinforced resin layer are cooled to room temperature after thermosetting, the liner made of synthetic resin shrinks greatly due to a large coefficient of linear expansion, whereas the fiber reinforced resin layer containing carbon fibers is made of carbon fibers. Elongates due to negative linear expansion coefficient. Due to this shrinkage difference, a gap is formed over substantially the entire area between the liner and the fiber reinforced resin layer. When various compressed gases such as compressed natural gas are filled in the hollow container in which this gap is generated, the liner made of synthetic resin will extend until it comes into contact with the fiber reinforced resin layer due to the high internal pressure due to various compressed gases. The durability of the liner was reduced. In particular, when the temperature is low, the elongation of the synthetic resin liner is reduced, and there is a risk that cracks may occur.

  In order to solve such a problem that a gap is generated between the liner and the fiber reinforced resin layer, in the method for manufacturing a high-pressure tank described in Patent Document 1 below, an elastomer or the like is formed in the gap formed after thermosetting. A step of filling the gap with an injection layer is provided.

Japanese Patent Laid-Open No. 10-231998

  However, in the method for manufacturing a high-pressure tank described in Patent Document 1, a process for injecting a material into the gap between the liner and the fiber reinforced resin layer is added to the conventional method for manufacturing a high-pressure tank. There was a problem that it would take.

  As a method different from the method of injecting the above material into the gap, the pressure between the liner and the fiber reinforced resin layer is increased by pressurization at the time of strength confirmation (pressure resistance test) by water pressure, which is essential in the conventional manufacturing process. There is a technique of filling the gap. In this case, although the manufacturing process does not increase, it is effective to shorten the time, but the drying process after the pressure resistance test is indispensable, so that moisture contained in the liner evaporates in this drying process. It becomes. Since the liner made of synthetic resin has good water absorption, the liner shrinks greatly when the moisture contained in the liner evaporates.Therefore, there is a possibility that a gap will be formed between the liner and the fiber reinforced resin layer again. It was. As described above, the conventional high-pressure tank manufacturing method has a problem that the gap between the liner and the fiber-reinforced resin layer cannot be reduced in a short time.

  The objective of this invention aims at providing the manufacturing method of the high pressure tank which can reduce the clearance gap between a liner and a fiber reinforced resin layer in a short time.

  In order to solve the above problems, a method for producing a high-pressure tank according to the present invention is the method for producing a high-pressure tank having a fiber reinforced resin layer in which a thermosetting resin is impregnated in an outer layer of a hollow liner serving as a tank container. The method includes a step of keeping the inside of the liner at a higher pressure than the outside of the high-pressure tank in a temperature atmosphere equal to or higher than the glass transition temperature of the liner.

  In the method for producing a high-pressure tank according to the present invention, the liner is kept radially outside, in other words, the liner is made of fiber reinforced resin by maintaining the inside of the liner at a pressure higher than the outside of the high-pressure tank at a temperature equal to or higher than the glass transition temperature of the liner. It can be deformed in the direction in which the layer is provided. For this reason, since the clearance gap between a liner and a fiber reinforced resin layer can be reduced, the intensity | strength of a high pressure tank can be improved. In addition, since a step of injecting a material into the gap between the liner and the fiber reinforced resin layer is not required, the time for this step can be reduced and the gap can be reduced in a short time.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the high pressure tank which can reduce the clearance gap between a liner and a fiber reinforced resin layer in a short time can be provided.

It is a schematic diagram which shows roughly the structure of a high pressure tank manufacturing apparatus. It is a graph for comparing the deformation amount of a liner. It is a graph for comparing the generated stress under extremely low temperatures between the method of the present invention and the conventional method.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The present invention is illustrated by the following preferred embodiments, but can be modified in many ways without departing from the scope of the present invention, and other embodiments other than this embodiment can be utilized. . Accordingly, all modifications within the scope of the present invention are included in the claims.

(High pressure tank)
First, the high-pressure tank 100 shown in FIG. 1 will be described. As shown in FIG. 1, the high-pressure tank 100 includes a tank body 110 having a substantially elliptical cross section, and a base portion 120 attached to an end of the tank body 110 in the longitudinal direction.

  The tank body 110 has, for example, a double structure, a liner 10 configured to be hollow so that a storage space is formed therein, and a fiber reinforced resin layer 20 as a reinforcing layer covering the outer surface of the liner 10. have. For example, a fluid made of compressed natural gas or hydrogen gas is stored in the storage space. The tank body 110 is provided with a temperature sensor (not shown) for monitoring the temperature inside the tank body 110.

  The liner 10 has substantially the same elliptical shape as that of the tank main body 110, and includes a substantially cylindrical body portion 11 and a dome-shaped side portion 12 continuous with an end portion of the body portion 11. The side portion 12 is provided with an opening 13 through which a fluid is supplied (or discharged). A base portion 120 is attached to the opening 13 and can be connected to a pipe 80 or the like. The liner 10 is a layer having gas barrier properties and suppressing permeation of hydrogen gas or the like to the outside. For example, it is made of a hard resin such as metal, polyethylene resin or polypropylene resin, and can be formed by laminating two or more layers. In the present embodiment, as the liner 10 material, a material having a glass transition temperature lower than that of the epoxy resin is used.

  The fiber reinforced resin layer 20 is a layer in which a thermosetting resin is reinforced with fibers, and is formed by winding fibers around the surface of the liner 10 by a filament winding method (hereinafter also referred to as “FW method”). . The fiber reinforced resin layer 20 has a configuration in which a plurality of fibers are stacked. The FW method is a method in which a reinforcing fiber impregnated with a thermosetting resin is wound around the liner 10 to thermoset the thermosetting resin. As the thermosetting resin, an epoxy resin, a polyester resin, a polyamide resin, or the like can be used. In this embodiment, an epoxy resin is used.

(High pressure tank manufacturing equipment)
Next, a high-pressure tank manufacturing apparatus 1 for manufacturing the above-described high-pressure tank 100 will be described with reference to FIG. FIG. 1 is a schematic diagram schematically showing the configuration of the high-pressure tank manufacturing apparatus 1.

  As shown in FIG. 1, the high-pressure tank manufacturing apparatus 1 includes a high-pressure tank 100, a sealed container 40, a room temperature gas supply device 50, a low temperature gas supply device 60, pressure increase means 70a and 70b, a mixing unit 90, Valves 50a and 60a and piping 80 connecting them are provided. The sealed container 40 is a case that houses the high-pressure tank 100 and seals it. In the following description, the piping 80 is omitted.

  The room temperature gas supply device 50 is connected to the high-pressure tank 100 through a valve 50 a and a mixing unit 90. The low temperature gas supply device 60 is connected to the high pressure tank 100 through a valve 60 a and a mixing unit 90. In the mixing unit 90, the normal temperature gas and the low temperature gas supplied from the normal temperature gas supply device 50 and the low temperature gas supply device 60 are mixed, and the mixed gas is supplied to the high pressure tank 100.

  Further, the room temperature gas supply device 50 or the low temperature gas supply device 60 is provided with boosting means 70a and 70b. For example, a pump or the like is used as the boosting means 70a and 70b. By operating the boosting means 70a and 70b, the high-pressure tank 100 can be filled with a normal temperature gas or a low temperature gas up to a predetermined pressure. Thus, the pressure inside the liner 10 can be kept higher than the outside of the high-pressure tank 100 by increasing the pressure inside the liner 10 by the pressure-increasing means 70a and 70b.

  Here, in general, when a tank is filled with a gas, the gas is filled against the pressure in the tank, so the temperature of the gas in the tank rises. Therefore, in this embodiment, when normal temperature gas or low temperature gas is filled in the high pressure tank 100, the valves 50a and 60a are opened by a control device (not shown) so that the temperature in the high pressure tank 100 is maintained at a predetermined temperature. The degree is controlled.

  As described above, for example, a pump or the like can be used as the boosting means 70a and 70b. However, other devices or the like can be appropriately selected as long as they have a function of increasing the pressure in the liner 10. it can. Further, the boosting means 70 a and 70 b can be installed in parts other than the room temperature gas supply device 50 or the low temperature gas supply device 60.

  In the present embodiment, the high-pressure tank manufacturing apparatus 1 is provided with the boosting means 70a and 70b having the boosting ability to reach the temperature in the liner 10 to a predetermined temperature. Extra equipment can be reduced.

  Moreover, in this embodiment, since the gas from which temperature differs can be mixed in the mixing part 90, and the mixed gas can be supplied to the high pressure tank 100, the temperature in the high pressure tank 100 can be quickly controlled to predetermined temperature. it can.

  Moreover, in this embodiment, since the airtight container 40 which accommodates and seals the high pressure tank 100 in the inside is provided, the exchange of air between the inside of the high pressure tank 100 and the outside of the high pressure tank 100 can be suppressed. For this reason, the temperature inside the high-pressure tank 100 can be maintained at a predetermined temperature.

(High pressure tank manufacturing method)
Then, the manufacturing process of the high pressure tank 100 using the high pressure tank manufacturing apparatus 1 shown in FIG. 1 is demonstrated. In addition, the manufacturing process of the high-pressure tank 100 described below is performed in an airtight inspection process which is a final process of the legal inspection. The airtight inspection process is a process for confirming leakage due to high-pressure gas. In the step before the airtightness inspection step, the step of forming the liner 10, the step of winding the fiber reinforced resin layer 20 covering the outer layer of the liner, the heat impregnating resin of the fiber reinforced resin layer 20 is heated and cured, Although the process etc. which cool to room temperature are performed after heat-curing, description about these processes performed before an airtight test process is abbreviate | omitted below.

  The contents performed in the airtight inspection process, which is the final process of the legal inspection, will be described below. First, the valve 50a shown in FIG. 1 is opened, normal temperature gas is supplied from the normal temperature gas supply device 50, and the high temperature tank 100 is rapidly filled with normal temperature gas. Since the high-pressure tank 100 is filled with the normal temperature gas, the temperature in the high-pressure tank 100 rises. The room temperature gas is filled so that the temperature in the high-pressure tank 100 becomes equal to or higher than a predetermined temperature (for example, higher than the glass transition temperature of the liner 10).

  Next, the valve 60 a is opened to supply the low temperature gas from the low temperature gas supply device 60, and the high pressure tank 100 is filled with the mixed gas mixed with the normal temperature gas. Then, in a state where the temperature in the high-pressure tank 100 is monitored by a temperature sensor (not shown), the temperature in the high-pressure tank 100 becomes a temperature between the glass transition temperature of the liner 10 and the glass transition temperature of the epoxy resin. The high pressure tank 100 is filled with the mixed gas so as to be maintained. The glass transition temperature of the epoxy resin is about 130 ° C.

  And it hold | maintains for 10 to 20 minutes in the state which maintained the temperature in the high pressure tank 100 between the glass transition temperature of the liner 10, and the glass transition temperature of an epoxy resin. That is, the inside of the liner 10 is held at a higher pressure than the outside of the high-pressure tank 100 in an atmosphere where the temperature in the high-pressure tank 100 is equal to or higher than the glass transition temperature of the liner 10.

  Finally, after a predetermined time has elapsed, the normal temperature gas or the low temperature gas filled in the high pressure tank 100 is discharged to the outside of the high pressure tank 100.

  According to the above process, the liner 10 can be deformed in the airtightness inspection process. As described above, in the step before the airtightness inspection step, when the liner 10 and the fiber reinforced resin layer 20 are cured by heating and then cooled, a gap is generated between the liner and the fiber reinforced resin layer. However, according to the present embodiment, since the liner 10 can be deformed in the airtightness inspection process, the gap generated in the process before the airtightness inspection process can be reduced.

  In the present embodiment, as described above, a material having a glass transition temperature lower than the glass transition temperature of the epoxy resin is used as the material of the liner 10. And since this liner 10 is provided with the process of maintaining the temperature in the high-pressure tank 100 so that it may become the temperature between the glass transition temperature of the liner 10 and the glass transition temperature of an epoxy resin, the liner 10 is provided. The liner 10 can be deformed radially outward, in other words, in the direction in which the fiber reinforced resin layer 20 is provided. For this reason, since the clearance gap between the liner 10 and the fiber reinforced resin layer 20 can be reduced, the intensity | strength of the high pressure tank 100 can be improved.

  In addition, the manufacturing process of the high-pressure tank 100 in the present embodiment is performed in an airtight inspection process that is also necessary in the conventional process. The gap with 20 can be reduced. As a result, an increase in cost and an increase in process time due to an increase in processes can be suppressed.

  Next, the deformation amount of the liner 10 will be described with reference to FIG. FIG. 2 is a graph for explaining the deformation amount of the liner 10. The horizontal axis of the graph of FIG. 2 represents time, and the vertical axis of the graph of FIG. 2 represents the deformation amount (strain) of the liner 10.

  As shown in FIG. 2, when the high-pressure tank 100 according to the present embodiment is manufactured, the deformation amount of the liner 10 increases in a short time (“high temperature” line in FIG. 2). The “high temperature” line in FIG. 2 represents the result when the temperature between the glass transition temperature of the liner 10 and the glass transition temperature of the epoxy resin is 70 degrees.

  For comparison, FIG. 2 shows the deformation amount of the liner 10 when the high-pressure tank 100 is manufactured while maintaining the temperature in the liner 10 at room temperature (“room temperature” line in FIG. 2). When maintained at room temperature, the amount of deformation of the liner 10 over time is small and is in a substantially constant state.

  As apparent from FIG. 2, when the high-pressure tank 100 is manufactured while maintaining the temperature in the liner 10 at a high temperature (for example, 70 ° C.), the high-pressure tank 100 is manufactured while maintaining the temperature in the liner 10 at room temperature. The amount of deformation of the liner 10 can be increased in a shorter time than when performing the above. Specifically, comparing the case of normal temperature and the case of high temperature, the deformation amount of the liner 10 is five times or more in the case of high temperature.

  According to the present embodiment, the deformation amount of the liner 10, more specifically, the plastic deformation amount of the liner 10 and the creep deformation amount of the liner 10 can be increased. In order to increase the amount of plastic deformation of the liner 10, it is necessary to apply a larger load pressure. However, in this embodiment, an excessive load pressure is not required, so that the high pressure tank 100 is damaged or the life of the high pressure tank 100 is increased. Can be reduced. Further, a longer time is required to increase the amount of creep deformation, but in this embodiment, the amount of creep deformation can be increased in a short time, and therefore, excess equipment due to a longer manufacturing process time. Investment can be reduced.

  Subsequently, the generated stress of the high-pressure tank 100 at an extremely low temperature will be described with reference to FIG. FIG. 3 is a diagram comparing the generated stress under the cryogenic temperature of the conventional method and the generated stress under the cryogenic temperature of the method of the present invention. The vertical axis of the graph in FIG. 3 represents the magnitude of the generated stress at extremely low temperatures.

  As shown in FIG. 3, the generated stress under the cryogenic temperature in the high-pressure tank 100 manufactured using the method of the present invention and the generated stress under the cryogenic temperature in the high-pressure tank 100 manufactured using the conventional method. , The method of the present invention can significantly reduce the stress generated at extremely low temperatures (about 70% of the conventional). This is because the method of the present invention can reduce the gap between the liner 10 and the fiber reinforced resin layer 20 as compared with the conventional method. Thus, since the technique of the present invention can reduce the stress generated at extremely low temperatures, the high-pressure tank 100 can be circulated at high speed even in extremely cold regions.

  As mentioned above, although embodiment of this invention was described, this is an illustration for description of this invention, Comprising: It is not the meaning which limits the scope of the present invention only to this embodiment. The present invention can be implemented in various other embodiments.

DESCRIPTION OF SYMBOLS 1 High pressure tank manufacturing apparatus 10 Liner 20 Fiber reinforced resin layer 40 Airtight container 50 Room temperature gas supply apparatus 60 Low temperature gas supply apparatus 100 High pressure tank 110 Tank main body

Claims (1)

In a method for producing a high-pressure tank having a fiber reinforced resin layer in which a thermosetting resin is impregnated in an outer layer of a hollow liner serving as a tank container,
A gas filling step of filling a gas into the high-pressure tank so as to be maintained at a temperature between the glass transition temperature of the liner and the glass transition temperature of the epoxy resin;
After the gas filling process, in a state where the inside of the liner was retained to a higher pressure than the outside of the high-pressure tank, the temperature of the high-pressure tank, between the glass transition temperature of the glass transition temperature and the epoxy resin of the liner Maintaining the temperature at 10 minutes for 10 minutes or more .

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