JP2013053729A - High pressure gas tank and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high pressure gas tank having a high pressure resistance, without causing disarray of winding, in a hoop layer constituting a fiber-reinforced layer.SOLUTION: This high pressure gas tank 1 has the fiber-reinforced layer 3, which has the hoop layer 3a comprising a carbon fiber 7 wound along a surface substantially perpendicular to a center axis of a tank liner 2 at least in a portion thereof. When the hoop layer 3a is viewed in the surface perpendicular to the center axis of the tank liner 2, a cross-sectional length of the carbon fiber 7 along a circumferential direction appearing on the surface is ≥20 times the diameter of the carbon fiber 7.

Description

  The present invention relates to a high-pressure gas tank, and more particularly to a high-pressure gas tank having a structure in which the outer periphery of a tank liner is covered with a fiber reinforced layer and a method for manufacturing the same.

  In recent years, development of high-pressure gas tanks used for high-pressure hydrogen tanks of fuel cell systems has been progressing. The high-pressure gas tank has a structure in which fibers are wound around the outer periphery of a tank liner, which is a container for storing gas, and a fiber reinforced layer is formed in order to prevent damage due to the pressure of the gas stored inside. It has been adopted.

  Various methods have been disclosed as a method for manufacturing a high-pressure gas tank having such a structure. For example, Patent Document 1 discloses a method of forming a hoop layer as a part of a fiber reinforced layer by winding fibers along a surface substantially perpendicular to the central axis of a tank liner.

  Patent Document 2 discloses a manufacturing method in which when a fiber is wound around the outer periphery of a tank liner, the fiber is wound while applying a predetermined tension to the fiber. Patent Document 2 further reduces the tension applied to the fibers as the number of layers of the wound fibers increases in order to suppress a decrease in the tension in the innermost layer of the fiber reinforced layers. A winding method is also disclosed.

JP 2010-265931 JP 2010-223243

  By the way, in a high pressure gas tank having a structure in which a hoop layer is formed as a fiber reinforced layer on the outer periphery of the tank liner, the pressure strength against the pressure of the stored high pressure gas may be remarkably lowered. When the present inventors examined the cause, it was found that voids in which fibers that should originally exist are formed in a portion where the pressure strength decreases. When gas is stored in the high-pressure gas tank, stress is generated in the hoop layer due to the pressure of the gas, but if a gap is formed in the hoop layer, stress is applied to the portion between the gap and the tank liner. Will be concentrated. As a result, the fibers constituting the hoop layer slipped with respect to the tank liner in this portion, and the pressure resistance of the high-pressure gas tank was thereby lowered.

  Furthermore, the present inventors examined the cause of the formation of voids in the hoop layer. When forming the hoop layer, if the fibers can be wound closely together in the same direction (perpendicular to the main axis of the tank), there should be no voids. Therefore, when winding the fiber around the tank liner, the present invention may cause winding disturbance depending on how the tension applied to the fiber is changed, and this winding disturbance is not the cause of void generation. I thought.

  More specifically, when the fiber is wound around the tank liner, the winding tension on the tank liner side, that is, the inner side is maximized, and the winding tension is continuously decreased toward the outer side. In this way, when winding the fiber around the tank liner, it is necessary to change the winding tension. Therefore, it is considered that winding disturbance has occurred in the process of the change.

  However, in order to avoid this winding disturbance or to ensure the strength as a high-pressure gas tank even if a certain amount of winding disturbance occurs, how to wind the fiber around the tank liner In the past, no investigation has been made.

  Therefore, the fiber winding method is set with a certain degree of expectation, and the high-pressure gas tank is manufactured by the set winding method. It has been determined whether or not the high-pressure gas tank manufactured in this way has a strength that can withstand practical use by performing a pressure fracture experiment. If a high-pressure gas tank is manufactured by such a method, it takes a lot of time and cost for the experiment and evaluation. Therefore, the evaluation of the disturbance of how the fiber is wound around the tank liner is accurately performed, and the pressure fracture experiment is not performed. There is a need to provide a high-pressure gas tank having high pressure strength.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a high-pressure gas tank having high pressure resistance in a high-pressure gas tank in which fibers are wound around a tank liner. Furthermore, it is an object of the present invention to provide a manufacturing method capable of simply determining whether or not winding disturbance that reduces the pressure resistance of the high-pressure gas tank has occurred, and providing a high-pressure gas tank having a high pressure strength.

  In order to solve the above-described problems, a high-pressure gas tank according to the present invention is a high-pressure gas tank having a tank liner and a fiber reinforced layer formed by winding fibers around an outer periphery of the tank liner. Has a hoop layer in which the fibers are wound along a plane substantially perpendicular to the central axis of the tank liner, at least in part, and the hoop layer is arranged with respect to the central axis of the tank liner. When viewed on a vertical surface, the length along the circumferential direction of the cross-sectional shape of the fiber appearing on the surface is 20 times or more the diameter of the fiber.

  When the hoop layer is viewed in a plane perpendicular to the central axis of the tank liner, in order to accurately evaluate the winding disturbance that reduces the pressure strength of the high-pressure gas tank, We focused on the cross-sectional shape of the fibers appearing in

  If the winding is not disturbed and the fibers are densely arranged along a plane substantially perpendicular to the central axis of the tank liner, the length along the circumferential direction of the cross-sectional shape of the fibers in the substantially vertical plane The length becomes sufficiently long, and the cross section is continuously observed over almost the entire circumference. On the other hand, at the location where the winding disturbance has occurred, the fiber is displaced in the direction along the central axis of the tank liner, so the length along the circumferential direction of the cross-sectional shape of the fiber in a substantially vertical plane is shortened, and the elliptical shape is reduced. Become an eggplant. The longer the angle formed by the fibers with respect to the central axis of the tank liner deviates from vertical, in other words, the greater the turbulence, the shorter the length along the circumferential direction of the cross-sectional shape of the fibers.

  In the high-pressure gas tank according to the present invention, when the hoop layer is viewed in a plane perpendicular to the central axis of the tank liner, the length along the circumferential direction of the cross-sectional shape of the fiber that appears on the surface is the diameter of the fiber. It is comprised so that it may become 20 times or more. Since the fiber is wound so as to satisfy this condition, the angle formed by the fiber with respect to the central axis of the tank liner does not deviate greatly from the vertical. Therefore, the gap formed due to the winding disturbance is sufficiently small, and the pressure resistance of the high-pressure gas tank is not reduced by the gap.

  The method for producing a high-pressure gas tank according to the present invention is a method for producing a high-pressure gas tank comprising a tank liner and a fiber reinforced layer formed by winding fibers around the outer periphery of the tank liner. A winding step of winding the fiber along a plane substantially perpendicular to the central axis of the tank liner to form a hoop layer, and a forming step of forming the fiber wound around the outer periphery of the tank liner with a fiber reinforced layer. In the winding step, when the hoop layer is viewed in a plane perpendicular to the central axis of the tank liner, the length along the circumferential direction of the cross-sectional shape of the fiber that appears on the plane is The fiber is wound so as to be 20 times or more the diameter of the fiber.

  In the method for manufacturing a high-pressure gas tank according to the present invention, when the hoop layer is viewed in a plane perpendicular to the central axis of the tank liner in the winding step of forming the hoop layer, the circumference of the cross-sectional shape of the fiber appearing on the surface is shown. The fiber is wound so that the length along the direction is 20 times or more the diameter of the fiber. By winding the fiber so as to satisfy this condition, the angle formed by the fiber with respect to the central axis of the tank liner does not deviate greatly from the vertical. Accordingly, since no gap is formed due to the winding disturbance, a high-pressure gas tank having a reduced pressure strength due to the gap is not manufactured.

  ADVANTAGE OF THE INVENTION According to this invention, the high pressure gas tank which has a high pressure strength can be provided in the high pressure gas tank formed by winding a fiber around a tank liner. Furthermore, it is possible to provide a manufacturing method that can easily determine whether or not a winding disturbance that reduces the pressure strength of the high-pressure gas tank has occurred, and provide a high-pressure gas tank having a high pressure strength.

It is sectional drawing which showed the structure of the high pressure gas tank which concerns on embodiment of this invention. It is sectional drawing which cut | disconnected the high pressure gas tank of FIG. 1 by the AA surface. It is a flowchart which shows the manufacturing process of the high pressure gas tank which concerns on embodiment of this invention. It is sectional drawing which expanded and showed the structure of the C section in FIG. FIG. 3 is a cross-sectional view illustrating a state in which the vicinity of a portion C in FIG. 2 is further cut by a surface (BB surface) along the circumferential direction of the tank liner 2. FIG. 5 is a cross-sectional view showing a portion corresponding to FIG. 4 in a high-pressure gas tank according to a comparative example of the present invention. FIG. 6 is a cross-sectional view showing a portion corresponding to FIG. 5 in a high-pressure gas tank according to a comparative example of the present invention. It is sectional drawing which expanded and showed the hoop layer 3a among the high pressure gas tanks shown in FIG. It is sectional drawing which showed the location corresponding to FIG. 8 in the high pressure gas tank which concerns on the comparative example of this invention. It is the flowchart which showed the inspection method of the high-pressure gas tank concerning the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  First, a high-pressure gas tank according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of a high-pressure gas tank 1 according to this embodiment. In FIG. 1, the cross section in the plane containing the central axis of the high-pressure gas tank 1 is shown. FIG. 2 shows a cross section of the high-pressure gas tank 1 of FIG. 1 as seen on a plane substantially perpendicular to the central axis of the high-pressure gas tank 1 (A-A plane, hereinafter also referred to as a substantially vertical plane 20).

  The high pressure gas tank 1 has a tank liner 2, a fiber reinforced layer 3, and a base 6. The tank liner 2 is disposed on the innermost side, and is a member having a cylindrical shape with both ends closed so that a gas such as hydrogen gas can be held therein. The tank liner 2 is made of, for example, polyethylene resin, polypropylene resin, or other hard resin. It may be formed of a metal such as aluminum.

  The base 6 is attached to one end of the tank liner 2 in the longitudinal direction, and functions as a gas inlet into the tank liner 2. More specifically, the base 6 is a metal part that has a substantially cylindrical shape and is fitted into the opening of the tank liner 2. The base 6 is used to connect to an external gas supply line when supplying hydrogen in the high-pressure gas tank 1 to the outside of the tank.

  The fiber reinforced layer 3 is a layer formed by winding fibers around the outer periphery of the tank liner 2. As will be described later, by winding the fiber along a surface substantially perpendicular to the central axis of the tank liner 2, a part is formed as the hoop layer 3a. In this embodiment, CFRP prepreg (carbon fiber impregnated with epoxy resin and epoxy resin is semi-cured and has a ribbon-like shape) is wound around the outer periphery of tank liner 2 and after winding is completed The fiber reinforced layer 3 is formed by thermosetting the epoxy resin. That is, the fiber reinforced layer 3 is formed by laminating the carbon fibers 7 and the adjacent carbon fibers 7 are bound by an epoxy resin not explicitly shown in the drawing.

  Then, the manufacturing method of the high pressure gas tank 1 which concerns on this embodiment is demonstrated. FIG. 3 is a flowchart showing a method for manufacturing the high-pressure gas tank 1 according to the present embodiment. As shown in FIG. 3, the manufacturing method of the high-pressure gas tank 1 includes a tank liner / cap assembly process S10, a winding process S20, a thermosetting process S30, and a pressure inspection process S40.

  In the tank liner / base assembling step S10, a part in which the base 6 is assembled to the tank liner 2 is prepared as part of the preparation process. In this case, the base 6 is not a special one but a general form.

  In the winding step S20 subsequent to the tank liner / cap assembly step S10, the outer surface of the tank liner 2 is CFRP prepreg (carbon fiber is impregnated with epoxy resin and epoxy resin is semi-cured, A non-cured fiber reinforced layer to be the fiber reinforced layer 3 is formed by winding and thermosetting.

  Details of the winding step S20 will be described. In the winding step S20, the CFRP prepreg is wound around the outer surface of the tank liner 2 with a winding tension F1 by the filament winding method.

  The winding tension F1 is preferably about 60 N at the start of the winding step S20. When wound with such a tension, the CFRP prepreg can be wound without loosening, and the generation of voids due to loosening is suppressed.

  Thereafter, the winding tension F1 is controlled to gradually decrease as the winding step S20 proceeds and the number of windings increases. In the present embodiment, the winding tension F1 at the time when the entire uncured fiber reinforced layer is formed is controlled to be about 30N. The winding tension F1 is not limited to a case where the winding tension F1 is decreased linearly as the number of windings increases from the start to the end of the winding step S20, and may be changed stepwise.

  The tension per cross-sectional area of the CFRP prepreg at the time when the winding step S20 is completed is preferably 10 MPa or more at the lowest place. According to experiments conducted by the present inventors, it has been found that when the pressure is less than 10 MPa, the winding disorder described later tends to occur, and the pressure resistance of the high-pressure gas tank decreases.

  The winding direction of the CFRP prepreg is along a plane substantially perpendicular to the central axis of the tank liner 2. That is, by using so-called hoop winding, a part of the fiber reinforced layer 3 is formed as the hoop layer 3a.

  In the thermosetting step S30 following the winding step S20, the thermosetting resin in the uncured fiber reinforced layer is cured by heating to form the fiber reinforced layer 3.

  In the pressurization inspection step S40 subsequent to the thermosetting step S30, a pressurization inspection for confirming whether the high-pressure gas tank 1 has a predetermined strength is performed. In the pressurization inspection step S40, the presence or absence of gas leakage is inspected in a state where the inside of the high-pressure gas tank is pressurized to a predetermined pressure.

  Next, details of the hoop layer 3a constituting the fiber reinforced layer 3 will be described with reference to FIG. FIG. 4 is an enlarged cross-sectional view showing the structure of the portion C in FIG. 2, and shows details of the hoop layer 3a. As described above, the hoop layer 3 a is formed by winding the CFRP prepreg along a plane substantially perpendicular to the central axis of the tank liner 2. For this reason, the cross-sectional shape of each carbon fiber 7 is observed continuously over substantially the entire circumference of the tank liner 2, and in FIG. 4, it appears as a laminar cross-sectional shape 21 a along the circumferential direction. Further, the cross-sectional shape of some of the carbon fibers 7a appears as an elliptical cross-sectional shape 21b. The reason for this will be described next.

  FIG. 5 is a cross-sectional view showing a state in which the vicinity of a portion C in FIG. 2 is viewed on a surface (B-B surface) along the circumferential direction of the tank liner 2. The dotted line in FIG. 5 shows the arrangement of the carbon fibers 7 on the opposite side across the substantially vertical plane 20 (AA plane) for reference. As shown in FIG. 5, some of the carbon fibers 7a obliquely cross the substantially vertical surface 20 (AA plane). The cross-sectional shape of such a carbon fiber 7a is an elliptical cross-sectional shape 21b as shown in FIG. The elliptical cross-sectional shape 21 b has a minor axis length that matches the diameter d of the carbon fiber 7.

  Here, if the angle formed by the winding direction of the carbon fiber 7 with respect to the plane perpendicular to the central axis of the tank liner 2 is represented by θ, the angle formed by the carbon fiber 7 with respect to the central axis of the tank liner 2 is 90 degrees. + Θ. In the winding step S20, since the hoop winding is performed as described above, the carbon fiber 7 is wound in a state where θ is maintained at approximately 0 degrees. However, depending on how to change the winding tension F1 in the winding step S20, the winding is disturbed, and θ becomes larger than 0 degrees as in the carbon fiber 7a in FIG.

  The relationship between the major axis L and θ of the elliptical cross-sectional shape 21b is L = d / sin (θ). In the present embodiment, when the hoop layer 3a is viewed in a plane perpendicular to the central axis of the tank liner 2, the length of the elliptical cross-sectional shape 21b appearing on the plane, that is, the major axis L is all the fiber. It is comprised so that it may become 20 times or more of the diameter d. As a result, the range of θ falls within the range of approximately 3 degrees or less.

  According to detailed experiments conducted by the present inventors, when the winding disturbance occurs such that θ exceeds 3 degrees in the hoop layer 3a, the pressure resistance strength of the high-pressure gas tank 1 is increased by the gap 23 formed in the portion. It has been found that it drops significantly. In the present embodiment, since θ does not exceed 3 degrees, the air gap 23 is not formed, and the pressure resistance of the high-pressure gas tank 1 is not significantly reduced due to winding disturbance.

  Next, the reason why the gap 23 is formed when θ is increased will be described. As shown in FIG. 4 and FIG. 5, when there is a carbon fiber 7a arranged so that θ is larger than 0 degree, the carbon fibers 7 are not densely arranged in that portion, and there is no surrounding area. A gap 22 is formed. The larger the θ, the larger the gap 22 formed.

  As in the present embodiment, when θ is small and within 3 degrees, the formed gap 22 is sufficiently small. For this reason, the epoxy resin of the CFRP prepreg enters the gap 22 and the gap 22 is filled. That is, when the heating step S40 is completed, no large bubbles remain in the gap 22, and no gap 23 is formed in the portion.

  On the other hand, unlike the present embodiment, the state of the hoop layer 3a when θ is formed largely due to winding disturbance is shown in FIGS. 6 and 7 as a comparative example. 6 is a cross-sectional view showing a portion corresponding to FIG. 4 in the high-pressure gas tank according to this comparative example, and FIG. 7 is a cross-sectional view showing a portion corresponding to FIG. 5 in the high-pressure gas tank according to this comparative example. FIG.

  In this comparative example, as shown in FIG. 6, the cross-sectional shape of the carbon fiber 7a, that is, the long diameter L of the elliptical cross-sectional shape 21b is the short diameter of the elliptical cross-sectional shape 21b (the diameter d of the carbon fiber 7a). Shorter than 20 times. That is, the carbon fiber 7 is greatly displaced in the direction along the central axis of the tank liner 2 due to the winding disturbance. As a result, the gap 22 formed around the carbon fiber 7a is large. Thus, when the gap 22 is formed large, even if the epoxy resin of the CFRP prepreg enters the gap 22, the gap 22 is not sufficiently filled. As a result, even when the heating step S40 is completed, a large bubble remains in the gap 22, and a void 23 is formed around the carbon fiber 7a.

  Next, the reason why the pressure strength of the high-pressure gas tank 1 is reduced due to the presence of the gap 23 will be described. FIG. 8 is an enlarged cross-sectional view of the hoop layer 3a in the high-pressure gas tank 1 shown in FIG. In FIG. 8, when the high-pressure gas tank 1 is used, that is, when the high-pressure gas tank 1 is filled with high-pressure gas, the stress distribution in the circumferential direction in the hoop layer 3a is indicated by arrows.

  In this state, a stress that is applied to the carbon fiber 7 in the winding step S20 and exists before the gas is filled, and a stress that is generated when the high-pressure gas tank 1 expands due to the pressure of the filled gas. Since the combined state is obtained, high stress is generated in the circumferential direction in the hoop layer 3a. How the stress in the circumferential direction is distributed in the hoop layer 3a is shown by the direction and size of the arrow in FIG.

  As apparent from FIG. 8, the circumferential stress in the hoop layer 3a is the smallest in the outermost peripheral portion and the largest in the innermost peripheral portion. Between the two, that is, inside the hoop layer 3a, the distribution is such that it smoothly changes according to the depth of the hoop layer 3a. In this state, the hoop layer 3a has sufficient strength.

  On the other hand, the stress distribution when the voids 23 are formed inside the hoop layer 3a is shown in FIG. 9 as a comparative example. FIG. 9 is a cross-sectional view showing a portion corresponding to FIG. 8 in the high-pressure gas tank according to this comparative example.

  In this comparative example, unlike FIG. 8, the distribution of stress acting on the hoop layer 3 a is discontinuously distributed with the gap 23 as a boundary. That is, the stress acting on the portion outside (upper side in the drawing) from the gap 23 is smaller than the stress in the present embodiment, and the stress acting on the portion inside (lower side in the drawing) from the gap 23 is It is larger than the stress at. As described above, the portion of the hoop layer 3a that is in contact with the tank liner 2 receives a large stress, and therefore the carbon fiber 7 constituting the hoop layer 3a slides toward the outside of the gap 23 inside the gap 23. End up. As a result, the pressure strength of the high-pressure gas tank 1 is reduced.

  In the high-pressure gas tank 1 according to the present embodiment, as already described, when the hoop layer 3a is viewed on the substantially vertical surface 20, the length along the circumferential direction of the cross-sectional shape 21b of the carbon fiber 7 appearing on the surface is shown. However, it is comprised so that it may become 20 times or more of the diameter of the carbon fiber 7. FIG. For this reason, the space | gap 23 is not formed in the hoop layer 3a, and the proof pressure strength of the high pressure gas tank 1 does not fall.

  Next, an inspection method for the high-pressure gas tank 1 according to the embodiment of the present invention will be described. FIG. 10 is a flowchart showing an inspection method for the high-pressure gas tank 1 according to the embodiment of the present invention. This inspection method is performed on the high-pressure gas tank 1 for the purpose of confirming that no winding disturbance has occurred after the pressurization inspection step 40 shown in FIG. As shown in FIG. 10, a cut surface acquisition step S50 and a determination step S60 are provided.

  First, in the cut surface acquisition step S50, a cut surface when the hoop layer 3a constituting the high pressure gas tank 1 is viewed in a plane perpendicular to the central axis of the high pressure gas tank 1 is acquired. This includes not only the case where the cut surface is acquired by cutting the hoop layer 3a but also the case where the cut surface is acquired as an image without actually cutting by tomography using X-ray CT or microwave.

  In the determination step S60 following the cut surface acquisition step S50, the length L of the cross-sectional shape along the circumferential direction of the carbon fiber 7 appearing on the cut surface acquired in the cut surface acquisition step S50 is It is determined whether it is 20 times or more of the diameter d.

  When it is determined that the length L of the cross-sectional shape along the circumferential direction is smaller than 20 times the diameter d of the carbon fiber 7, winding disturbances that reduce the pressure resistance of the high-pressure gas tank 1 occur. Therefore, it is determined as a failure and the inspection is terminated (S100).

  When it is determined that the length L of the cross-sectional shape along the circumferential direction is 20 times or more the diameter d of the carbon fiber 7, the winding is disturbed so as to reduce the pressure resistance of the high-pressure gas tank 1 in that portion. Since it is presumed that it has not occurred, the process proceeds to determination of the cross-sectional shape of another part (S70, S80). The above is performed about the cross-sectional shape of all the carbon fibers 7 which appear in the cut surface acquired by cut surface acquisition process S50 (S70). For all cross-sectional shapes, when it is determined that the length L of the cross-sectional shape along the circumferential direction is 20 times or more the diameter d of the carbon fiber 7, the pressure resistance strength of the high-pressure gas tank 1 in the entire hoop layer 3a Since it is presumed that there is no winding disturbance to the extent that the temperature is lowered, it is determined to be acceptable and the inspection is terminated (S90).

  According to this inspection method, it is determined whether or not winding disturbance has occurred by a simple method of observing the cross-sectional shape of the carbon fiber 7 appearing on the cut surface of the hoop layer 3a without performing a pressure breakdown test, It is possible to provide a high-strength high-pressure gas tank 1.

  In addition, in the cut surface acquisition step S60, if the cut surface of the hoop layer 3a is acquired by tomography using X-ray CT or microwave, the high pressure gas tank 1 can be inspected without being destroyed, and thus the product. It can also be performed as a pre-shipment inspection of the high-pressure gas tank 1.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, but can be changed as appropriate. Moreover, each element with which each embodiment mentioned above is provided can be combined as long as technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

DESCRIPTION OF SYMBOLS 1 High pressure gas tank 2 Tank liner 3 Fiber reinforcement layer 6 Base 7 Carbon fiber 20 Substantially vertical surface 21a Layered cross-sectional shape 21b Elliptical cross-sectional shape 22 Gap 23 Space | gap

Claims (2)

In a high-pressure gas tank having a tank liner and a fiber reinforced layer formed by winding fibers around the outer periphery of the tank liner,
The fiber reinforced layer has, at least in part, a hoop layer in which the fibers are wound along a surface substantially perpendicular to the central axis of the tank liner,
When the hoop layer is viewed in a plane perpendicular to the central axis of the tank liner, the length along the circumferential direction of the cross-sectional shape of the fiber appearing on the plane is 20 times or more the diameter of the fiber. A high-pressure gas tank characterized by being. In a method for producing a high-pressure gas tank, comprising a tank liner and a fiber reinforced layer formed by winding fibers around the outer periphery of the tank liner,
A winding step of winding the fiber around the outer periphery of the tank liner along a plane substantially perpendicular to the central axis of the tank liner to form a hoop layer;
Forming the fiber wound around the outer periphery of the tank liner with a fiber reinforced layer, and
In the winding step, when the hoop layer is viewed in a plane perpendicular to the central axis of the tank liner, the length along the circumferential direction of the cross-sectional shape of the fiber that appears on the surface is the diameter of the fiber The method of manufacturing a high-pressure gas tank, wherein the fiber is wound so as to be 20 times or more.

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