High pressure tank

Abstract

To provide a high pressure tank having high resistance to a bending moment acting on a mouth piece.SOLUTION: A high pressure tank disclosed by the specification includes a liner, a reinforcement layer covering the liner, and a mouth piece attached to an opening of the reinforcement layer. The mouth piece includes: a cylinder part extending to the outside of the tank through the opening of the reinforcement layer; and a flange provided at the cylinder part. The flange expands along an inner surface of the reinforcement layer. The mouth piece has following characteristics. On a tank cross section passing through an axis of the mouth piece, a border between the cylinder part and the flange is formed as an arc-shaped curve line. A point where a surface of the reinforcement layer (a surface facing the outside of the tank) contacts with the mouth piece is located on the arc-shaped curve line.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present specification relates to a high-pressure tank for use as a hydrogen tank mounted on a fuel cell vehicle, for example. [Background technology]

[0002] A high-pressure tank comprises a liner that confines the high-pressure gas, a reinforcing layer that covers the liner, and a mouthpiece that serves as an inlet and outlet for the gas. The mouthpiece is attached to the opening in the reinforcing layer. The mouthpiece comprises a cylindrical portion that passes through the opening in the reinforcing layer and extends to the outside of the tank, and a flange attached to the cylindrical portion. The flange extends along the inner surface of the reinforcing layer (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-156312 A [Patent Document 2] JP 2021-113560 A Summary of the Invention [Problem to be solved by the invention]

[0004] The mouthpiece is attached to the opening of the reinforcing layer. Although the axis of the mouthpiece and the axis of the reinforcing layer are usually aligned, if an external force (bending moment) that makes the axes non-parallel is applied to the mouthpiece, the reinforcing layer may be damaged in the vicinity of the mouthpiece, resulting in a decrease in strength. This specification provides a high-pressure tank that is highly resistant to bending moments. [Means for solving the problem]

[0005] The high-pressure tank disclosed in this specification comprises a liner, a reinforcing layer covering the liner, and a nozzle attached to an opening of the reinforcing layer. The nozzle comprises a tubular portion extending to the outside of the tank through the opening of the reinforcing layer, and a flange provided on the tubular portion. The flange extends along the inner surface of the reinforcing layer. The nozzle further has the following features. In a tank cross section passing through the axis of the nozzle, the boundary between the tubular portion and the flange is an arc curve, and the point where the surface of the reinforcing layer (the surface facing the outside of the tank) touches the nozzle is located on the arc curve. In other words, the reinforcing layer does not touch the nozzle on the tip side of the nozzle relative to the arc curved boundary region (the boundary region between the tubular portion and the flange).

[0006] If the reinforcing layer extends to the vicinity of the tip of the nozzle, a strong force may be generated in the reinforcing layer facing the tubular portion when a bending moment (a moment centered on a straight line perpendicular to the axis) acts on the nozzle. This force may damage the reinforcing layer and reduce its strength. The reinforcing layer of the high-pressure tank disclosed in this specification does not contact the nozzle on the nozzle tip side beyond the arc-curved boundary region (the boundary region between the tubular portion and the flange). Therefore, it is possible to suppress the reduction in strength of the reinforcing layer that occurs near the tubular portion of the nozzle when a moment is applied in conventional high-pressure tanks.

[0007] Details and further improvements of the technology disclosed in this specification are described in the following "Forms for Carrying Out the Invention". [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view of the high-pressure tank of the first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating the area enclosed by the dashed rectangle II in FIG. [Diagram 3] FIG. 4 is a cross-sectional view of a high-pressure tank of a comparative example. [Figure 4] FIG. 6 is a cross-sectional view of a high-pressure tank according to a second embodiment. [Diagram 5] FIG. 11 is a cross-sectional view of a high-pressure tank according to a third embodiment. [Figure 6] FIG. 11 is a cross-sectional view of a high-pressure tank according to a fourth embodiment. [Figure 7]FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (First embodiment) FIG. 1 shows a cross-sectional view of a high-pressure tank 100 of a first embodiment. FIG. 1 is a partial cross-sectional view of the vicinity of the nozzle of the high-pressure tank 100. The high-pressure tank 100 is long, and the dashed line CL in the figure represents the axis (center line) of the high-pressure tank 100. The high-pressure tank 100 includes a liner 110, a reinforcing layer 120, and a nozzle 130, and the axis CL (center line CL) corresponds to the axis of these tanks. The liner 110, the reinforcing layer 120, and the nozzle 130 are symmetrical about the axis CL, and a cross section cut along any plane including the axis CL is equal to FIG. 1. In other words, FIG. 1 shows a cross section passing through the axis of the nozzle 130 (high-pressure tank 100). The X-axis of the coordinate system in the figure is parallel to the axis CL, and the Y-axis and Z-axis are perpendicular to the axis CL.

[0010] The liner 110 is a thin-walled cylinder made of metal or resin, and is a container for storing high-pressure gas inside. The reinforcing layer 120 is a cylinder that covers the liner 110 and reinforces the liner 110. More specifically, the reinforcing layer 120 protects the liner 110 from external impacts and suppresses expansion of the liner 110 due to the high-pressure gas inside the liner. The reinforcing layer 120 is made of a material in which multilayered mesh-like carbon fibers are solidified with resin, that is, carbon fiber reinforced plastics (CFRP).

[0011] The liner 110 and the reinforcing layer 120 have an opening at one end in the axial direction (the left side in FIG. 1), and a nozzle 130 is attached to the opening. The nozzle 130 has a cylindrical portion 131 that communicates with the inside and outside of the high-pressure tank 100, and a flange 132 attached to the cylindrical portion 131. The cylindrical portion 131 and the flange 132 are made of metal and are integrated together. A valve (not shown) is attached to the tip of the cylindrical portion 131 (the end of the nozzle located outside the reinforcing layer 120). The flange 132 is provided on the rear end side of the cylindrical portion 131 and is located inside the high-pressure tank 100. One surface of the flange 132 (the flange surface facing the outside of the high-pressure tank 100) extends along the reinforcing layer. The liner 110 extends to the other surface of the flange 132 (the flange surface facing the inside of the high-pressure tank 100).

[0012] A cross section of the area enclosed by the dashed rectangle II in Fig. 1 is shown in Fig. 2. Although the axis CL is not shown in Fig. 2, the X-axis of the coordinate system in the figure represents the direction of the axis.

[0013] In Fig. 2 (i.e., in a tank cross section passing through the axis of the nozzle 130), a boundary 133 between the surface of the tubular portion 131 and the surface of the flange 132 is an arc curve of radius R. The two-dot chain circle 129 depicted in Fig. 2 is an imaginary circle of radius R drawn with an auxiliary line. In the cross section of Fig. 2, the boundary 133 overlaps with a part of the circle 129 of radius R. A point 122 where a surface 121 of the reinforcing layer 120 (the surface facing the outside of the tank) touches the nozzle 130 is located on the boundary 133 of the arc curve. In other words, in the cross section of Fig. 2 (a cross section including the axis), the opening of the reinforcing layer 120 is curved along an imaginary circle of radius R that overlaps with the boundary 133.

[0014] In the case of the high-pressure tank 100 of the first embodiment, a point 122 where a surface 121 of the reinforcing layer 120 contacts the ferrule 130 is located at an end of a boundary 133 of the arc curve (the end on the side of the tubular portion 131). The reinforcing layer 120 is joined to the ferrule 130 at the flange 132 and the boundary 133. The reinforcing layer 120 does not contact the tubular portion 131.

[0015] The structural feature that the point 122 where the surface 121 of the reinforcing layer 120 contacts the base 130 is located on the boundary 133 of the circular arc curve has the following effect: This feature suppresses a decrease in the strength of the reinforcing layer 120 in the vicinity of the base 130 when a bending moment (a moment about an axis perpendicular to the axis) acts on the base 130.

[0016] The above-mentioned advantages will be explained with reference to Fig. 3. Fig. 3 is a cross-sectional view of a high-pressure tank 900 of a comparative example (a conventional high-pressure tank). The high-pressure tank 900 has a liner 910, a mouthpiece 930, and a reinforcing layer 920. The shapes of the liner 910 and the mouthpiece 930 are the same as the shapes of the liner 110 and the mouthpiece 130 of the high-pressure tank 100 of the embodiment. In the mouthpiece 930, a boundary 933 between a cylindrical portion 931 and a flange 932 is an arc curve of a radius R. The circle indicated by the reference numeral 929 is a virtual circle 929 of radius R that overlaps with the boundary 933.

[0017] The reinforcing layer 920 is joined to the base 930 at a boundary 933 with a flange 932 of the base 930, and is also joined to a part 934 of the tubular part 931. In other words, in the cross section of FIG. 3, the opening of the reinforcing layer 920 protrudes toward the tip side of the base 930 beyond an imaginary circle 929 of radius R that overlaps with the boundary 933. When a moment M acts on the base 930, a strong force in the Z direction (a force acting radially from the axis in the YZ plane) acts on the reinforcing layer 920 facing the part 934 of the tubular part 931. The reinforcing layer 920 is made of carbon fiber wound in multiple layers and solidified with resin, and this force acts to delaminate the multiple layers of carbon fiber. When delamination occurs, the strength of the reinforcing layer 120 decreases.

[0018] On the other hand, as shown in FIG. 2, in the high-pressure tank 100 of the embodiment, the reinforcing layer 120 is joined to the flange 132 and the boundary 133 at the base 130, but is not in contact with the surface of the cylindrical portion 131 parallel to the axis (X-axis). Therefore, the high-pressure tank 100 can suppress the force generated in the reinforcing layer 120 near the cylindrical portion 131. As a result, the high-pressure tank 100 can suppress the decrease in strength of the reinforcing layer 120 when a bending moment is applied. When a bending moment is applied, a force is generated in the reinforcing layer 120 even in a portion facing the boundary 133. However, since the boundary 133 is an arc-shaped curve, the force generated in the reinforcing layer 120 in the portion facing the boundary 133 is smaller than the force generated in the reinforcing layer 920 facing the linear portion 934 in the high-pressure tank 900 of the comparative example.

[0019] (Second embodiment) Fig. 4 shows a cross section of a high-pressure tank 200 of a second embodiment. Fig. 4 is a view corresponding to Fig. 2. The high-pressure tank 200 comprises a liner 210, a reinforcing layer 220, and a mouthpiece 230. The shapes of the liner 210 and the mouthpiece 230 are the same as those of the high-pressure tank 100 of the first embodiment. The mouthpiece 230 comprises a cylindrical portion 231 that communicates between the inside and outside of the tank, and a flange 232 that extends along the inner surface of the reinforcing layer 220. A boundary 233 between the cylindrical portion 231 and the flange 232 is an arc curve with a radius R. The two-dot chain circle 229 is an imaginary circle with a radius R drawn with an auxiliary line.

[0020] In the cross section of Fig. 4 (cross section of the high-pressure tank 200 cut along a plane including the axis), point 222 where surface 221 (surface facing the outside of the tank) of reinforcing layer 220 meets the surface of nozzle 230 is located midway, not at the end, of boundary 233, which is a circular arc curve. In other words, surface 221 of reinforcing layer 220 passes inside imaginary circle 229 that overlaps boundary 233 of nozzle 230. Even with this shape (structure), the high-pressure tank 200 of the second embodiment can achieve the same effects as the high-pressure tank 100 of the first embodiment.

[0021] (Third embodiment) Fig. 5 shows a cross section of a high-pressure tank 300 of a third embodiment. Fig. 5 is a view corresponding to Fig. 2. The high-pressure tank 300 includes a liner 310, a reinforcing layer 320, and a cap 330. The shapes of the liner 310 and the cap 330 are the same as those of the high-pressure tank 100 of the first embodiment. The cap 330 includes a cylindrical portion 331 that communicates between the inside and outside of the tank, and a flange 332 that extends along the inner surface of the reinforcing layer 320. A boundary 333 between the cylindrical portion 331 and the flange 332 is an arc curve with a radius R. A two-dot chain circle 329 is a virtual circle with a radius R drawn by an auxiliary line. In the high-pressure tanks of the first and second embodiments, the boundary (boundaries 133, 233) between the cylindrical portion and the flange was an arc with a range of about 90 degrees in the cross sections of Figs. 2 and 4. In the case of the high-pressure tank 300 of the third embodiment, a boundary 333 between the surface of the cylindrical portion 331 and the surface of the flange 332 extends over a range exceeding 90 degrees.

[0022] In the cross section of Fig. 5 (cross section of the high-pressure tank 300 cut along a plane including the axis), point 322 where surface 321 (surface facing the outside of the tank) of reinforcing layer 320 meets the surface of nozzle 330 is located at the end of boundary 333 which is a circular arc curve. In other words, in the cross section of Fig. 5 (cross section passing through the axis), the opening of reinforcing layer 320 is curved along imaginary circle 329 of radius R which overlaps with boundary 333 of nozzle 330. The high-pressure tank 300 of the third embodiment also provides the same effects as the high-pressure tank 100 of the first embodiment.

[0023] In the high-pressure tank 300 of the third embodiment, the nozzle 330 has a recess 334 at the boundary 333. The reinforcing layer 320 has a protrusion 323 that fits into the recess 334 of the nozzle 330. By providing the protrusion 323 that fits into the recess 334, it is possible to prevent the nozzle 330 from rotating around the axis relative to the reinforcing layer 320. The nozzle 330 may have a plurality of recesses 334 that are equally spaced in the circumferential direction of the nozzle 330. In this case, the reinforcing layer 320 may have a plurality of protrusions 323 that fit into the plurality of recesses 334, respectively.

[0024] The reinforcing layer 320 having the protrusions 323 is manufactured by the following process. A cap 230 having a recess 334 is attached to the liner 310. The recess 334 is then filled with a resin (uncured resin) such as epoxy. Carbon fiber is wound from the liner 310 to the boundary 333 of the cap 330. Finally, the carbon fiber is hardened with the resin. When the carbon fiber is hardened with the resin, the epoxy filled in the recess 334 also hardens, and the reinforcing layer 320 having the protrusions 323 is completed.

[0025] A high-pressure tank 400 according to a fourth embodiment will be described with reference to Figures 6 and 7. Figure 6 shows a cross section of the high-pressure tank 400 according to the fourth embodiment. Figure 6 is a view corresponding to Figure 2. The high-pressure tank 400 includes a liner 410, a reinforcing layer 420, and a cap 430. A rubber cap 440 is used in the manufacturing process of the high-pressure tank 400. The shape of the liner 410 is the same as that of the high-pressure tank 100 according to the first embodiment.

[0026] The nozzle 330 includes a cylindrical portion 431 that communicates between the inside and outside of the tank, and a flange 432 that extends along the inner surface of the reinforcing layer 420. A boundary 433 between the cylindrical portion 431 and the flange 432 is an arc curve with a radius R. A two-dot chain circle 429 is an imaginary circle with a radius R drawn with an auxiliary line. The boundary 433 between the cylindrical portion 431 and the flange 432 is an arc with an angle of approximately 90 degrees in the cross section of FIG. 6 (cross section including the axis).

[0027] As described above, reinforcing layer 420 is formed by solidifying carbon fiber wound in multiple layers with resin. Prior to winding the carbon fiber, rubber cap 440 is attached to tube portion 431. After rubber cap 440 is attached, carbon fiber is wound and solidified with resin to form reinforcing layer 420. Then, rubber cap 440 is removed. Figure 6 shows the state after reinforcing layer 420 is completed and before rubber cap 440 is removed.

[0028] Rubber cap 440 has recesses 441 on the surface facing reinforcing layer 420. Fig. 7 shows a cross section taken along line VII-VII in Fig. 6. Fig. 7 depicts the entire circumference of mouthpiece 430 and rubber cap 440. As shown in Fig. 7, rubber cap 440 has a plurality of recesses 441 arranged at equal intervals along the circumferential direction. Rubber cap 440 having recesses 441 is less likely to come off tubular portion 341 when carbon fiber is wound around it.

[0029] In the cross section of Fig. 6 (cross section of high-pressure tank 400 cut along a plane including the axis), point 422 where surface 421 (surface facing the outside of the tank) of reinforcing layer 420 meets the surface of nozzle 430 is located at the end of boundary 433 which is a circular arc curve. In other words, in the cross section of Fig. 6 (cross section passing through the axis), the opening of reinforcing layer 420 is curved along imaginary circle 429 of radius R which overlaps with boundary 433 of nozzle 430. The high-pressure tank 400 of the fourth embodiment also provides the same effects as the high-pressure tank 100 of the first embodiment.

[0030] In the high-pressure tank 400, the diameter of the tubular portion 431 of the nozzle 430 is smaller than the diameter of the tubular portion 131 of the high-pressure tank 100 of the first embodiment. A gap is generated between the reinforcing layer 420 and the nozzle 430 (tubular portion 431) outside the nozzle (right side in FIG. 6) of a point 422 where the surface 421 of the reinforcing layer 420 contacts the surface of the nozzle 430. A cylindrical rubber cap 440 is fitted into the tube portion 431 of the nozzle 430 so as to fill this gap. By removing the rubber cap 440 after the reinforcing layer 420 is completed, a gap of a precise shape can be left between the reinforcing layer 420 and the nozzle 430 (tubular portion 431).

[0031] Some of the features of the technology described in the embodiments are listed below. Note that the technical elements described below are independent technical elements that exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

[0032] The high-pressure tank of the embodiment comprises a liner, a reinforcing layer covering the liner, and a nozzle attached to the opening of the reinforcing layer. The nozzle comprises a cylindrical portion extending to the outside of the tank through the opening in the reinforcing layer, and a flange provided on the cylindrical portion. The flange extends along the inner surface of the reinforcing layer. In a cross section passing through the axis of the nozzle, the boundary between the cylindrical portion and the flange forms a circular arc curve. The point where the surface of the reinforcing layer contacts the nozzle is located on the circular arc curve. The reinforcing layer is joined to the nozzle at the boundary with the flange, and does not contact the cylindrical portion on the tip side of the boundary (the end of the nozzle outside the tank).

[0033] The base 330 has a recess 334 at a boundary 333, and the reinforcing layer 320 has a protrusion 323 that fits into the recess 334. The engagement between the recess 334 and the protrusion 323 strengthens the bond between the reinforcing layer 320 and the base 330. The engagement between the recess 334 and the protrusion 323 also prevents the base 330 from shifting about the axis relative to the reinforcing layer 320.

[0034] A plurality of recesses 334 may be arranged at equal intervals along the circumferential direction of the base when viewed along the axis of the base. The reinforcing layer 320 may be provided with protrusions 323 that fit into the respective recesses 334.

[0035] Prior to forming the reinforcing layer, a cylindrical rubber cap may be fitted to the tubular portion. After the reinforcing layer is formed, the rubber cap is removed. By using the rubber cap, a precisely shaped gap can be left between the reinforcing layer and the tubular portion. The rubber cap may have a plurality of depressions on a surface facing the reinforcing layer when viewed along the axis. Furthermore, the plurality of depressions may be equally spaced around the circumference of the rubber cap. For example, three depressions may be provided around the circumference of the rubber cap at 120 degree intervals.

[0036] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. [Explanation of symbols]

[0037] 100, 200, 300, 400: High pressure tank 110, 210, 310, 410: Liner 120, 220, 320, 420: Reinforcing layer 129, 229, 329, 429: Virtual circle 130, 230, 330, 430: Cap 131, 231, 331, 431: Cylinder 132, 232, 332, 432: Flange 133, 233, 333, 433: Boundary 323: Protrusion 334: Depression 440: Rubber cap 441: Depression CL: Axial line

Claims

[Claim 1] Raina and a reinforcing layer covering the liner; a cap attached to the opening of the reinforcing layer; Equipped with the cap includes a cylindrical portion extending to the outside of the tank through an opening in the reinforcing layer, and a flange provided on the cylindrical portion and extending along an inner surface of the reinforcing layer, In a cross section passing through an axis of the base, a boundary between the cylindrical portion and the flange is an arc-shaped curve, and a point where a surface of the reinforcing layer is tangent to the base is located on the arc-shaped curve. High pressure tank.

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