JP4849324B2 - High pressure tank - Google Patents

Description

  The present invention relates to a high-pressure tank for storing a high-pressure fluid whose pressure is increased compared to normal pressure.

  In recent years, development of high-pressure hydrogen tanks used in fuel cell systems has been progressing. The filling pressure of hydrogen gas in the high-pressure hydrogen tank was initially 20 MPa or 35 MPa, but recently 70 MPa has become possible. The higher the filling pressure, the longer the travelable distance of a fuel cell vehicle equipped with a high-pressure hydrogen tank. However, the high-pressure hydrogen tank needs to have a strength (burst strength) that can withstand a high filling pressure.

  A conventional general high-pressure tank is provided with a reinforcing layer in which fibers impregnated with a resin are wound around the outer peripheral surface of a liner (see, for example, Patent Document 1). The liner functions as a barrier layer that suppresses permeation of high-pressure gas stored in the high-pressure tank. On the other hand, the reinforcing layer suppresses the expansion of the liner due to the high-pressure gas and ensures the burst strength of the high-pressure tank.

Conventionally, in order to increase the burst strength, a method of increasing the thickness of the liner and the thickness of the reinforcing layer has been taken. However, this method is not preferable because the tank becomes large and the load weight increases. Therefore, in the high-pressure tank described in Patent Document 1, in order to improve the pressure resistance of the resin liner, a liner resin having a tensile breaking elongation of 50% or more is used.
JP 2003-56702 A (page 3)

  However, according to the experiments of the present inventors, it has been found that the material is not used effectively. In particular, the high-pressure tank described in Patent Document 1 may be broken from the inside of the reinforcing layer.

  The present invention has been made paying attention to the fact that the original strength of the reinforcing layer is not effectively utilized in the conventional tank, and provides a high-pressure tank capable of improving the burst strength and reducing the thickness. Is the purpose.

In order to achieve the above object, the high-pressure tank of the present invention is a high-pressure tank having a barrier layer that suppresses permeation of high-pressure fluid, and a reinforcing layer that suppresses expansion of the barrier layer outside the barrier layer, reinforcing layer, a resin having at least two layers reinforced with fibers, a layer located inside of the serial least two layers, than the layer located on the outside, the tensile elongation at break per unit volume a large It is configured to listen and tensile modulus is small, the resin and fiber layers located inside, rather than the resin and fiber layers located outside, tensile elongation at break respectively is configured in size Kunar so Is.

According to this configuration, the inner side of the reinforcing layer is prevented from breaking before the outer side. Thereby, the contribution to the intensity | strength of a reinforcement layer can be improved about the outer part in a reinforcement layer. Therefore, it is not necessary to increase the wall thickness in order to obtain the required burst strength by effectively utilizing the original reinforcing layer. In addition, the reinforcing layer has at least two layers in which the resin is reinforced with fibers, and the inner layer of at least two layers has a tensile elongation at break larger than that of the outer layer. Since the elongation can be set in units of layers, the reinforcing layer can be easily configured. Further, in the reinforcing layer, since the resin and fiber of the layer located on the inner side have a larger tensile break elongation than the resin and fiber of the layer located on the outer side, the physical property value of the tensile break elongation can be easily set. Furthermore, in the reinforcing layer, the inner layer is smaller in tensile modulus than the outer layer, so that the inner layer extends in the reinforcing layer, so that stress can be released to the outer layer. The stress can be received by the outer layer. Thereby, in the reinforcing layer, both the inner layer and the outer layer can bear more uniform stress.

  Here, the “tensile elongation at break” in the present invention refers to the strain at the yield point, not the strain at the break point. Further, the “tensile breaking elongation” in the present invention is a tensile breaking elongation in a direction intersecting the radial direction, more preferably in a tangential direction of the circumference.

  Preferably, the reinforcing layer is configured so that the tensile elongation at break increases from the outside to the inside.

  By carrying out like this, it can suppress further more suitably that an inner side fractures before an outside in a reinforcement layer.

  Preferably, the reinforcing layer is a layer in which fibers are wound by a filament winding method, and the reinforcing layer is at least one of the composition of the fibers, the tension when the fibers are wound, the cross-sectional area of the fibers, and the composition of the resin. By making a difference between the outer layer and the inner layer, the tensile breaking elongation per unit volume is made larger on the inner side than on the outer side.

  According to the high-pressure tank of the present invention, the burst strength can be increased and the wall thickness can be reduced.

  Hereinafter, an example in which a high pressure tank according to a preferred embodiment of the present invention is applied to a fuel cell system will be described with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a view showing a fuel cell vehicle equipped with a tank according to this embodiment.
The fuel cell vehicle 100 is equipped with a fuel cell system 200 having a fuel cell 104. In the fuel cell system 200, for example, three high-pressure tanks 1 are mounted on the rear part of the vehicle body. The fluid in each high-pressure tank 1 is a combustible fuel gas such as hydrogen gas or compressed natural gas, and is supplied to the fuel cell 104 through the gas supply line 102. Below, hydrogen gas is demonstrated to an example as fuel gas which high pressure tank 1 stores.

  Note that the high-pressure tank 1 can be applied not only to fuel cell vehicles but also to vehicles such as electric vehicles and hybrid vehicles, as well as various moving bodies (for example, ships, airplanes, robots, etc.) and stationary types.

FIG. 2 is a cross-sectional view of the high-pressure tank 1.
The high-pressure tank 1 has a structure including a liner 3 formed in a hollow shape so as to define a storage space 2 therein, and a reinforcing layer 4 composed of a plurality of layers covering the outer surface of the liner 3. .

  The storage space 2 can store normal pressure fluid, and is configured to store fuel gas at a pressure higher than normal pressure (that is, high pressure). For example, hydrogen gas of 35 MPa or 70 MPa is stored in the storage space 2. The temperature of the high-pressure tank 1 fluctuates with the filling and releasing of hydrogen gas. The fluctuation range varies depending on the filling pressure of the hydrogen gas. The higher the filling pressure, the higher the temperature of the high-pressure tank 1 at the time of releasing the hydrogen gas. It becomes cooler. For example, the operating temperature band (variation range) of the 70 MPa high-pressure tank 1 is approximately −70 ° C. to 100 ° C.

  The tank body 5 including the liner 3 and the reinforcing layer 4 has openings 6 and 7 through which hydrogen gas is supplied / discharged at the center of both ends in the longitudinal direction. Valve assemblies and plugs (not shown) are directly connected to the openings 6 and 7 by screw connection or the like. Alternatively, a base (not shown) is provided in the openings 6 and 7 by insert molding or the like, and a valve assembly or the like is screwed and connected through the base. The valve assembly and the external gas supply line 102 are connected, and hydrogen gas is supplied to and discharged from the storage space 2. One of the openings 6 and 7 may be omitted.

  Focusing on the overall shape of the tank body 5, the tank body 5 is composed of a body portion 10 and a pair of dome portions 11 and 12. The trunk portion 10 is a substantially cylindrical portion extending a predetermined length in the axial direction of the tank body 5, that is, the longitudinal direction, and has a substantially constant diameter. The pair of dome portions 11 and 12 are hemispherical curved wall portions that are respectively continuous with both longitudinal ends of the body portion 10. The pair of dome portions 11 and 12 are reduced in diameter as they move away from the body portion 10, and have the openings 6 and 7 at the center of the most reduced diameter portion. The pair of dome portions 11 and 12 are formed in a throttle shape so as to close both ends of the body portion 10, and constitute a longitudinal end wall portion of the tank body 5.

  The liner 3 is a portion that can also be referred to as an inner shell or an inner container of the tank 1, and constitutes the inner wall of the body portion 10 and the pair of dome portions 11 and 12. The liner 3 has a gas barrier property and suppresses permeation of hydrogen gas to the outside. That is, the liner 3 functions as a barrier layer.

  The material of the liner 3 is not particularly limited, and examples thereof include polyethylene, polypropylene resin, and other hard resins in addition to metals. Further, the liner 3 may be configured as a laminated body composed of a plurality of layers by combining these resins into two or more layers. The thickness of the liner 3 depends on the material, the dimensional shape of the high-pressure tank 1, the required pressure resistance, etc., but is not particularly limited, and is preferably about 0.5 mm to several tens of mm, more preferably about 1 mm to 10 mm. It is.

  The reinforcing layer 4 is a part that can be referred to as an outer shell, a shell, or an outer container of the tank 1, and constitutes an outer wall of the trunk portion 10 and the pair of dome portions 11 and 12. The reinforcing layer 4 is formed by being wound around the liner 3 so as to cover the outer surface of the liner 3, and suppresses expansion of the liner 3 outside the liner 3.

  The reinforcing layer 4 is an FRP layer in which a matrix resin (plastic) is reinforced with fibers.

  Examples of the matrix resin include an epoxy resin, a modified epoxy resin, an unsaturated polyester resin, a polypropylene resin, and the like. Among these, an epoxy resin or an unsaturated polyester resin is more preferable. A thermosetting resin is preferably used as the matrix resin.

  Examples of reinforcing fibers include inorganic fibers such as metal fibers, glass fibers, carbon fibers, and alumina fibers, synthetic organic fibers such as aramid fibers, and natural organic fibers such as cotton. These fibers can be used alone or in combination (as mixed fibers), and among these, carbon fibers and aramid fibers are particularly preferable. In the reinforcing layer 4 of the present embodiment, carbon fiber is used.

  The content ratio of the matrix resin and the fiber in the reinforcing layer 4 depends on the kind of the resin and fiber, the fiber reinforcing direction, the thickness, and the like, but usually preferably the matrix resin: fiber = 10 to 80% by volume: 90 to It is 20 volume%, More preferably, the ratio shall be 25-50 volume%: 75-50 volume%. The reinforcing layer 4 may contain an appropriate additive in addition to these constituent materials.

  The thickness of the reinforcing layer 4 is not particularly limited, although it depends on the material, the size and shape of the tank 1, the required pressure resistance, etc., preferably about several mm, more preferably about several mm to 50 mm. When the outer diameter of the body 10 is about 300 mmφ, it is often about 20 mm. As will be described later, in the high-pressure tank 1 of the present invention, the reinforcing layer 4 is devised so that the burst strength can be ensured without increasing the thickness.

  The reinforcing layer 4 (CFRP layer) is composed of a plurality of layers. The number of layers constituting the reinforcing layer 4 is 16 in one embodiment, and is 4 in this embodiment. However, the number of layers depends on the size and shape of the tank 1, the required pressure resistance, etc., but is preferably at least two. The at least two layers preferably include a hoop layer and a helical layer. The order of stacking the hoop layer and the helical layer is arbitrary, but as in the present embodiment, the hoop layer 21, the helical layer 31, the hoop layer 22, and the helical layer 32 are alternately adjacent to each other in order from the liner 3. It is preferable to laminate (see FIG. 3).

  The hoop layers 21 and 22 are wound around the entire body at the position of the body portion 10. Specifically, the hoop layer 21 is configured by hooping carbon fibers around the outer surface of the body portion of the liner 3 and curing the resin impregnated in the carbon fibers. The hoop layer 22 is formed by hooping carbon fibers around the outer surface of the helical layer 31 at a position corresponding to the body portion 10 and curing the resin impregnated in the carbon fibers. The hoop layers 21 and 22 configured in this way ensure the strength of the body portion 10 in the circumferential direction.

  The helical layers 31 and 32 are wound around substantially the whole at the positions of the trunk portion 10 and the dome portions 11 and 12. Specifically, the helical layer 31 is configured by helically winding carbon fibers around the outer surface of the dome portion of the liner 3 and the outer surface of the hoop layer 21 and curing the resin impregnated in the carbon fibers. The helical layer 32 is formed by helically winding carbon fibers on the outer surface of the hoop layer 22 at a position corresponding to the body portion 10 and on the outer surface of the helical layer 31 at positions corresponding to the dome portions 11 and 12. It is configured by curing a resin impregnated in the fiber. The helical layers 31 and 32 thus configured mainly ensure the strength of the dome portions 11 and 12 and ensure the strength of the tank 1 in the longitudinal direction.

  For both the hoop winding and the helical winding, for example, a filament winding method (FW method), a hand layup method, a tape winding method, or the like may be used, and the filament winding method is preferably used. The carbon fiber wound by the filament winding method is, for example, one impregnated with resin since it is wound on a bobbin or the like (that is, in a prepreg state), or drawn out from the bobbin or the like to be resin. The tank is impregnated with resin.

  Here, the reinforcing layer 4 of the present embodiment is configured such that the tensile breaking elongation per unit volume is larger on the inner side than on the outer side. “Tensile rupture elongation per unit volume” refers to the tensile rupture elongation of the reinforcing layer 4 virtually cut out. “Tensile elongation at break” refers to the strain in the circumferential direction at the yield point, not the strain at the break. This circumferential strain is also called circumferential strain. “Outside” of “outside to outside” refers to the radially outer side of the reinforcing layer 4, and “inside” refers to the radially inner side of the reinforcing layer 4.

  In a preferred aspect of the present embodiment, the hoop layer 21 and the helical layer 31 that are relatively located on the inner side of the reinforcing layer 4 have a tensile elongation at break than the hoop layer 22 and the helical layer 32 that are located relatively on the outer side. Is structured largely. However, a different combination may be used. For example, the tensile breaking elongation of the hoop layer 21 may be larger than that of the remaining three layers (31, 22, 32). When there are three hoop layers and three helical layers, the reinforcing layer 4 may be configured so that the tensile elongation at break increases from the outside to the inside. In short, it is sufficient that the reinforcing layer 4 is composed of at least two layers, and the tensile break elongation of the inner layer is larger than that of the outer layer.

  The above-described setting of the tensile elongation at break in the reinforcing layer 4 is the inner layer of the reinforcing layer 4 with respect to at least one of the carbon fiber composition, the tension when winding the carbon fiber, the cross-sectional area of the carbon fiber, and the matrix resin composition. This is realized by making a difference between the (hoop layer 21 and the helical layer 31) and the outer layer (the hoop layer 22 and the helical layer 32). Hereinafter, examples using different materials will be described with reference to FIGS. 4 to 6, and examples using the same material will be described with reference to FIGS. 7 and 8.

FIG. 4 is a graph showing the relationship between the circumferential stress σ _t and strain ε of the inner layer in the reinforcing layer 4.
This inner layer has a yield stress of σ _y and a tensile break elongation of δ. Using the yield stress σ _y and the tensile elongation at break δ, the area is divided into four regions (A) to (D) as shown in FIG. In this case, the outer layer in the reinforcing layer 4 may be configured using a material whose tensile breaking elongation is located in the region (c) or (d). That is, the carbon fiber and the matrix resin in the outer layer may be made of a material (composition) having a smaller tensile breaking elongation than the carbon fiber and the matrix resin in the inner layer, respectively. In addition, if comprised in this way, the magnitude of the yield stress is not ask | required between an inner layer and an outer layer.

  Preferably, the outer layer of the reinforcing layer 4 has a higher elastic modulus (Young's modulus) than the inner layer. In other words, if the outer layer of the reinforcing layer 4 is made of a material whose tensile breaking elongation is located in the region (c), it has a larger elastic modulus (Young's modulus) and smaller tensile breaking elongation than the inner layer. Become. The effect of setting the elastic modulus will be described with reference to FIGS. 5 and 6, the liner 3 is omitted.

FIG. 5 relates to a comparative example, and is a diagram showing a stress distribution of the circumferential stress σ _t ′ when the reinforcing layer 4 ′ is made of the same material in the thickness direction (radial direction).
When the high-pressure tank 1 receives the internal pressure P, a circumferential stress σ _t ′ acts in the circumferential direction of the reinforcing layer 4. This circumferential stress σ _t ′ becomes maximum on the inner diameter side and gradually decreases relatively rapidly toward the outer diameter side.

FIG. 6 relates to the present embodiment, and is a diagram showing the stress distribution of the circumferential stress σ _t when the outer side of the reinforcing layer 4 is made of a material having a larger elastic modulus than the inner side.
Since the outer layer has a larger elastic modulus than the inner layer, the circumferential stress σ _t is maximum on the inner diameter side, but is substantially uniform as a whole in the thickness direction. This is because, in the reinforcing layer 4, the inner layer extends, so that the circumferential stress can be released to the outer layer, while the outer layer does not extend as much as the inner layer. It is because it can be accepted. Therefore, when the reinforcing layer 4 extends outward due to the internal pressure P, the contribution of the outer layer to the strength can be improved as compared to the case where the same material (matrix resin, carbon fiber) is used for all.

  Next, referring to FIG. 7 and FIG. 8, the material (matrix resin and carbon fiber) is the same in the entire region of the reinforcing layer 4, and the tensile breaking elongation of the inner layer is set to the tensile breaking elongation of the outer layer. Two examples that can be made substantially larger are described.

  FIG. 7B partially shows the state of the inner and outer carbon fibers in the reinforcing layer 4 in a state where the internal pressure does not act on the high-pressure tank 1. As shown in FIG. 7B, the carbon fibers on the inner side of the reinforcing layer 4 are contracted (sagging), whereas the elongation of the outer carbon fibers is zero. Reference numeral 40 shown in FIG. 7B indicates a minute volume in the reinforcing layer 4. In FIG. 7B, the liner 3 is omitted.

In FIG. 7A, the horizontal axis is the amount of elongation of the minute volume 40, and the vertical axis is the circumferential stress acting on the carbon fiber in the minute volume 40.
As shown in FIG. 7A, in the characteristic L1 of the outer carbon fiber, the circumferential stress becomes zero when the elongation of the minute volume 40 is zero. In the characteristic L1, the circumferential stress increases as the elongation of the minute volume 40 increases. When the elongation of the minute volume 40 is δ ₂ , the circumferential stress reaches the yield stress.

In contrast, in the characteristic L2 of the inner carbon fiber, the circumferential stress remains zero until the elongation of the minute volume 40 reaches δ ₁ . This is because the inner carbon fiber is shrunk when the internal pressure is not acting. In the characteristic L2, as the elongation of the minute volume 40 becomes larger than δ ₁ , the circumferential stress increases. When the elongation of the minute volume 40 is δ ₃ (> δ ₂ ), the circumferential stress reaches the yield stress. .

  Similarly, FIG. 8B partially shows the state of the inner and outer carbon fibers of the reinforcing layer 4 in a state where the internal pressure is not acting on the high-pressure tank 1. As shown in FIG. 8B, the elongation of the outer carbon fibers of the reinforcing layer 4 is greater than zero, while the elongation of the inner carbon fibers is zero. Reference numeral 50 shown in FIG. 8B indicates a minute volume in the reinforcing layer 4. In FIG. 8B, the liner 3 is omitted.

In FIG. 8A, the horizontal axis represents the elongation amount of the minute volume 50, and the vertical axis represents the circumferential stress acting on the carbon fiber in the minute volume 50.
As shown in FIG. 8A, in the characteristic L4 of the inner carbon fiber, the circumferential stress becomes zero when the elongation of the minute volume 50 is zero. And the characteristic L4, hoop stress as elongation of small volume 50 is greater increases, when growth of the micro-volume 50 is [delta] _5, hoop stress reaches the yield stress.

On the other hand, in the characteristic L3 of the outer carbon fiber, the circumferential stress σ ₁ acts from the time when the elongation of the minute volume 50 is zero. This is because the outer carbon fibers are stretched when the internal pressure is not acting. In the characteristic L3, the circumferential stress increases as the elongation of the minute volume 50 increases. When the elongation of the minute volume 50 is δ ₄ (<δ ₅ ), the circumferential stress reaches the yield stress.

  Therefore, by setting the carbon fiber as shown in FIG. 7B or FIG. 8B, the reinforcing layer 4 has substantially the tensile breaking elongation of the inner layer with respect to the tensile breaking elongation of the outer layer. It is possible to make it larger. Such a carbon fiber can be set by adjusting the tension at the time of winding the carbon fiber in the filament winding method. Specifically, the inner carbon fiber shown in FIG. 7B is wound with a tension smaller than that of the outer carbon fiber. Further, the outer carbon fiber shown in FIG. 8 is wound with a larger tension than the inner carbon fiber.

  Next, with reference to FIGS. 9 and 10, the design values of the outer carbon fibers with respect to the inner carbon fibers in the reinforcing layer 4 will be briefly described. Here, it is assumed that the inner carbon fiber (hereinafter abbreviated as “inner fiber”) and the outer carbon fiber (hereinafter abbreviated as “outer fiber”) break simultaneously. 9 and 10, the liner 3 is omitted.

  FIG. 9 assumes that the density has decreased after the high-pressure tank 1 has expanded due to internal pressure. That is, FIG. 9 is based on the premise that the inner displacement and the outer displacement of the reinforcing layer 4 are the same even after expansion.

  As shown in FIG. 9, the inner diameter of the reinforcing layer 4 is R1, the outer diameter is R2, the wall thickness is t, and the breaking elongation of the inner diameter side fiber (that is, the inner fiber) is Z. At this time, the inner circumference at break, the inner diameter at break, the outer diameter at break, and the outer circumference at break can be expressed as shown in FIG. 9B. And since the elongation of the outer fiber at the time of breaking can be defined by the following equation (1), it can be expressed as shown in FIG.

  Elongation of outer fiber at break = (outer circumference at break-initial outer circumference) / initial outer circumference (1)

That is, at the thickness t from the inner diameter R1 (ie, the position of the outer diameter R2), the elongation from the initial stage
R1 × Z / (R1 + t)
It is assumed that it breaks when it becomes.

In this case, as shown in FIG. 4, when different fibers are used on the inner side and the outer side of the reinforcing layer 4, the outer fiber at the position of the outer diameter R2 has a tensile elongation at break.
R1 × Z / (R1 + t)
What should be used. Specific numbers are as shown in FIG.

On the other hand, as shown in FIG. 8, when the same fiber is used on the inside and outside of the reinforcing layer 4, the outside fiber at the position of the outer diameter R2 is
Difference in elongation: Z−R1 × Z / (R1 + t)
It is sufficient to use a stretched one.

  FIG. 10 is a case on the premise that the density remains unchanged even after the high-pressure tank 1 is expanded by the internal pressure. That is, FIG. 10 is based on the premise that the cross-sectional area of the reinforcing layer 4 is constant even after expansion. Also in this case, as shown in FIG. 9A, the inner diameter of the reinforcing layer 4 is R1, the outer diameter is R2, and the wall thickness is t. Moreover, let the breaking elongation of an inner side fiber be Z. At this time, the inner circumference at break, the inner diameter at break, the outer diameter at break, and the outer circumference at break can be expressed as shown in FIG.

And since the cross-sectional area before and behind expansion is constant, the following equation holds.
πR2 ² −πR1 ² = π√ [π (R1 + t) ² −πR1 ² + π {R1 (1 + Z)} ² ] ² −πR1 (1 + Z)} ² (2)
Since the elongation Y of the outer fiber at break can be defined by the above formula (1), it can be expressed as follows when formula (2) is substituted and arranged.
Y = 2π × √ [π (R1 + t) ² −πR1 ² + π {R1 (1 + Z)} ² ]

  That is, in the case of FIG. 10 as well as in the case of FIG. 9, when the wall thickness t is from the inner diameter R1 (that is, the position of the outer diameter R2), the elongation from the initial stage is the above-described elongation Y, and the fracture Assuming that

  In this case, as shown in FIG. 4, when different fibers are used for the inner side and the outer side of the reinforcing layer 4, the outer fiber at the position of the outer diameter R2 should be the one whose tensile breaking elongation is the above-mentioned elongation Y. Good. Specific numbers are as shown in FIG.

On the other hand, as shown in FIG. 8, when the same fiber is used on the inside and outside of the reinforcing layer 4, the outside fiber at the position of the outer diameter R2 is
Difference in elongation: Z-Y
It is sufficient to use a stretched one.

  As described above, according to the high-pressure tank 1 of the present embodiment, the fibers and the resin that constitute the reinforcing layer 4 are configured such that the radial inner side is larger in tensile elongation than the radial outer side. For this reason, in the reinforcement layer 4, it is suppressed that an inner side fractures | ruptures ahead of an outer side. Thereby, about the outer part in the reinforcement layer 4, the capability to a yield point can be utilized effectively and the contribution to the intensity | strength of the reinforcement layer 4 can be improved. Therefore, by using the reinforcing layer 4 effectively, it is not necessary to increase the thickness in order to obtain the required burst strength.

It is a figure which shows the fuel cell vehicle carrying the tank which concerns on embodiment. It is sectional drawing of the tank which concerns on embodiment. It is principal part sectional drawing of the tank which expands and shows the part enclosed with the dashed-dotted line III of FIG. It is a graph which shows the relationship between the circumferential stress (sigma) _t and distortion | strain (epsilon) of the inner layer in the reinforcement layer which concerns on embodiment. It is a figure which concerns on a comparative example, and is a figure which shows the stress distribution of the circumferential stress in case a reinforcement layer is comprised with the same material in the thickness direction. It is a figure which concerns on this embodiment, and is a figure which shows the stress distribution of the circumferential stress when the outer side of a reinforcement layer is comprised with the material whose elastic modulus is larger than an inner side. (A) is a graph showing the amount of elongation of a minute volume on the horizontal axis and the circumferential stress acting on the carbon fiber in the minute volume on the horizontal axis, and (B) is an internal pressure not acting on the high-pressure tank. It is a figure which shows the state of an inner side and an outer side carbon fiber partially about the reinforcement layer of a state. (A) is a graph showing the amount of elongation of a minute volume on the horizontal axis and the circumferential stress acting on the carbon fiber in the minute volume on the horizontal axis, and (B) is an internal pressure not acting on the high-pressure tank. It is a figure which shows the state of an inner side and an outer side carbon fiber partially about the reinforcement layer of a state. (A) is sectional drawing which shows typically the reinforcement layer of a high-pressure tank with a dimension, (B) shows the specific example at the time of assuming that the density became small after the high-pressure tank expanded by internal pressure. It is a table. It is a table | surface which shows the specific example in the case of assuming that a density does not change after a high pressure tank expand | swells by internal pressure.

Explanation of symbols

  1: High pressure tank, 3: Liner (barrier layer), 4: Reinforcement layer, 21: Hoop layer, 22: Hoop layer, 31: Helical layer, 32: Helical layer

Claims (3)

A high-pressure tank having a barrier layer that suppresses permeation of high-pressure fluid, and a reinforcing layer that suppresses expansion of the barrier layer outside the barrier layer,
The reinforcing layer has at least two layers in which a resin is reinforced with fibers,
Layer located inside one of the at least two layers, than the layer located on the outside, the tensile elongation at break per unit volume is configured such that greatly and tensile modulus becomes smaller,
The high-pressure tank in which the resin and fiber in the inner layer are larger in tensile breaking elongation than the resin and fiber in the outer layer .   The high-pressure tank according to claim 1, wherein the reinforcing layer is configured to increase tensile elongation at break from the outside to the inside. The reinforcing layer is a layer in which fibers are wound by a filament winding method,
The composition of the fiber, wound upon the tension of the fibers, the cross-sectional area of the fiber, and for at least one composition of the resin, by putting the difference between the outer layer and the inner layer of the reinforcement layer, The high-pressure tank according to claim 1 or 2 , wherein the tensile breaking elongation per unit volume is larger on the inner side than on the outer side.

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