High Pressure Tank

Abstract

To provide a technique for securing fire resistance performance without covering the whole outer surface of a reinforcing layer with a fire resistant member.SOLUTION: A high pressure tank includes a liner having a center axis, the reinforcing layer covering the outer periphery of the liner, and a fire resistant sheet covering part of the reinforcing layer in the peripheral direction of the high pressure tank, the fire resistant sheet having a fire resistant layer including an expanded graphite to be expanded by temperature rise. In such an arrangement attitude that the high pressure tank is arranged to make the axial direction along the center axis correspond to the horizontal direction, the fire resistant sheet covers at least part of the lower half of the reinforcing layer in the gravity direction, without covering a partial region including the top of the reinforcing layer.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to high pressure tanks. [Background technology]

[0002] Conventionally, in a high-pressure tank having a reinforcing layer, a technique is known in which a fire-resistant cover is arranged on the outer surface of the reinforcing layer (Patent Document 1). This fire-resistant cover is formed of a ceramic fiber sheet, a glass mat, and a glass cloth. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 1-299400 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, in order to ensure fire resistance throughout the entire high-pressure tank, it was necessary to cover the entire outer surface of the reinforcing layer with a fire-resistant cover. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one embodiment of the present disclosure, a high-pressure tank is provided. The high-pressure tank includes a liner having a central axis, a reinforcing layer covering the outer periphery of the liner, and a fireproof sheet covering a part of the reinforcing layer in the circumferential direction of the high-pressure tank, the fireproof sheet having a fireproof layer containing expandable graphite that expands with an increase in temperature. When the high-pressure tank is placed in an arrangement position such that the axial direction along the central axis coincides with the horizontal direction, the fireproof sheet does not cover a part of the area including the top of the reinforcing layer, but covers at least a lower half of the reinforcing layer in the direction of gravity. According to this embodiment, when the high-pressure tank is heated by being exposed to a heat source such as a flame from below, the fireproof layer expands with the increase in temperature of the fireproof sheet. This can reduce the amount of heat transferred to the reinforcing layer. Furthermore, the expanded fireproof layer acts as a barrier to prevent the flame from reaching the top side. Therefore, the fireproof performance of the entire high-pressure tank can be ensured without covering the entire outer surface of the reinforcing layer with a fireproof sheet having fire resistance. (2) The above embodiment may further include an auxiliary fireproof sheet arranged on the outer periphery of the reinforcing layer, the auxiliary fireproof sheet being arranged to straddle a horizontal plane including the central axis when in the arrangement position, and the auxiliary fireproof sheet may have the fireproof layer. According to this embodiment, by providing the auxiliary fireproof sheet at a position straddling a horizontal plane including the central axis, the thickness of the laminated portion where the fireproof sheet and the auxiliary fireproof sheet are laminated can be increased more than other portions. This can further reduce the amount of heat transmitted to the reinforcing layer side. Furthermore, since the laminated portion is arranged on the side located midway between the top and the bottom opposite the top, the side portion expands further, which can further prevent the flame from reaching the top side. (3) The above embodiment may further include a fireproof member that does not include the expanded graphite, and the fireproof member may be disposed between the reinforcing layer and the fireproof sheet so as to straddle a horizontal plane including the central axis when in the disposition position. According to this embodiment, the fireproof member is disposed at a position straddling a horizontal plane including the central axis. This can further reduce the amount of heat transferred to the reinforcing layer. (4) In the above embodiment, the fire-resistant member may be formed of a fire-resistant paint. According to this embodiment, a coating film serving as the fire-resistant member can be formed by applying a fire-resistant paint to a portion of the outer surface of the reinforcing layer. This makes it possible to improve the fire resistance of the entire high-pressure tank without significantly increasing the weight of the high-pressure tank, even if the fire-resistant member is disposed between the reinforcing layer and the fire-resistant sheet. Furthermore, the fire-resistant member can be easily formed by applying a fire-resistant paint to a portion of the reinforcing layer. (5) In the above embodiment, the fireproof sheet may further have a tank replacement reference layer, which is a layer having a different color from the reinforcing layer and is disposed closer to the reinforcing layer than the fireproof layer. According to this embodiment, the tank replacement reference layer having a different color from the reinforcing layer is disposed closer to the reinforcing layer than the fireproof layer. This makes it possible to determine from the appearance whether the damaged area has reached the reinforcing layer when the outer surface of the high-pressure tank is damaged. Therefore, it is possible to easily determine whether the reinforcing layer is scratched. The present disclosure may be realized in various forms other than the high-pressure tank described above, for example, in the form of a manufacturing method of a high-pressure tank. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a cross-sectional schematic view showing a schematic configuration of a high-pressure tank according to the first embodiment. [Diagram 2] FIG. 4 is a diagram for explaining the positions at which a fireproof sheet and a resin sheet are formed. [Diagram 3] Cross-sectional view of 3-3 in Figure 2. [Figure 4] FIG. 2 is a diagram for explaining the configuration of a fire-resistant sheet. [Diagram 5] FIG. 4 is a diagram illustrating a configuration of a resin sheet. [Figure 6] 5A to 5C are diagrams for explaining the change in shape of the fireproof sheet and the state of the flame before and after expansion. [Figure 7] FIG. 11 is a schematic diagram showing the configuration of a high-pressure tank in a second embodiment. [Figure 8] FIG. 11 is a schematic diagram showing the configuration of a high-pressure tank in a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A. First embodiment: FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a high-pressure tank 100 in the first embodiment. FIG. 1 shows a cross-sectional view of the high-pressure tank 100 taken along a central axis O. FIG. 1 depicts an X-axis, a Y-axis, and a Z-axis as mutually orthogonal axes. The directions in which the arrows of the X-axis, Y-axis, and Z-axis point indicate positive directions along the X-axis, Y-axis, and Z-axis, respectively. The positive directions along the X-axis, Y-axis, and Z-axis are respectively referred to as the +X direction, +Y direction, and +Z direction. The directions opposite to the directions in which the arrows of the X-axis, Y-axis, and Z-axis point are negative directions along the X-axis, Y-axis, and Z-axis. The negative directions along the X-axis, Y-axis, and Z-axis are respectively referred to as the -X direction, -Y direction, and -Z direction. The directions along the X-axis, Y-axis, and Z-axis, regardless of whether they are positive or negative, are referred to as the X direction, Y direction, and Z direction, respectively.

[0009] In this embodiment, the X direction is a direction along the central axis O of the high-pressure tank 100. The Y direction is a direction along the direction of gravity in an arrangement posture of the high-pressure tank 100 described below. The -Y direction coincides with the direction of gravity in the arrangement posture. In the following drawings and explanations, in the radial direction of the high-pressure tank 100, the side approaching the central axis O is referred to as the radial inner side, and the side away from the central axis O is referred to as the radial outer side.

[0010] The high-pressure tank 100 is mounted on, for example, a fuel cell vehicle and is used to store hydrogen gas at high pressure to be supplied to the fuel cell. The high-pressure tank 100 includes a liner 10, a reinforcing layer 20, a valve-side nozzle 30, an end-side nozzle 40, a fireproof sheet 71, and a resin sheet 81.

[0011] The liner 10 is a hollow container that forms an internal space 10p for storing a fluid such as hydrogen gas. The liner 10 is formed of a resin having gas barrier properties such as a polyamide resin. The central axis of the liner 10 is the same as the central axis O of the high-pressure tank 100.

[0012] The reinforcing layer 20 is a layer for reinforcing the liner 10. The reinforcing layer 20 covers the outer periphery of the liner 10. The material for forming the reinforcing layer 20 is, for example, a fiber-reinforced resin such as CFRP (Carbon Fiber Reinforced Plastics). The reinforcing layer 20 is formed, for example, by a filament winding method. Specifically, carbon fiber impregnated with a thermosetting resin such as an epoxy resin is wound around the liner 10 to form a plurality of layers in the circumferential direction CD. Thereafter, the thermosetting resin is thermally cured by heating to form the reinforcing layer 20. Note that the types of fiber material and thermosetting resin for forming the reinforcing layer 20 are not limited to those mentioned above. The fiber material used for forming the reinforcing layer 20 may include, for example, glass fiber.

[0013] The container body 90 of the high-pressure tank 100 is composed of a liner 10 and a reinforcing layer 20. The container body 90 has a main body portion 910, a first dome portion 930, and a second dome portion 950. The main body portion 910 is formed by a part of the liner 10 and the reinforcing layer 20. The shape of the main body portion 910 is cylindrical.

[0014] The first dome portion 930 and the second dome portion 950 are portions of the container body 90 other than the main body portion 910, and are provided at both ends of the main body portion 910. Specifically, the first dome portion 930 is provided in the main body portion 910, continuous with one end portion 30r in the axial direction OD along the central axis O. The shape of the first dome portion 930 is a dome shape (spherical shape) protruding from the one end portion 30r of the main body portion 910 toward the valve-side nozzle 30. The diameter of the first dome portion 930 decreases with increasing distance from the main body portion 910. The tip portion 10r of the liner 10 in the first dome portion 930 is curved so as to enter the internal space 10p side. The curved tip portion 10r of the liner 10 forms an opening 10d.

[0015] The second dome portion 950 is provided continuously to the other end 40s, which is the end opposite to the one end 30r, of the main body portion 910. The second dome portion 950 has a dome shape (spherical shape) that protrudes from the other end 40s of the main body portion 910 toward the end side base 40. The diameter of the second dome portion 950 decreases with increasing distance from the main body portion 910.

[0016] The valve side nozzle 30 is attached to the opening 10d. The shape of the valve side nozzle 30 is generally cylindrical so as to connect the internal space 10p of the liner 10 with the outside. The inner peripheral surface of the valve side nozzle 30 functions as an inlet and outlet for the stored matter (hereinafter, the stored matter) such as hydrogen gas stored in the internal space 10p. A valve 50 is attached to the valve side nozzle 30.

[0017] The valve 50 is a member for opening and closing the inlet and outlet of the stored material through the valve-side mouthpiece 30. By closing the valve 50, the inside of the liner 10 is sealed. The valve 50 has a pressure adjustment mechanism 51.

[0018] The pressure adjustment mechanism 51 adjusts the opening of the valve 50 so as to reduce the internal pressure to a predetermined value when the internal pressure of the high-pressure tank 100 exceeds a preset value. For example, when the temperature of the outer surfaces 71a, 81a of the high-pressure tank 100 rises to a predetermined temperature, the pressure adjustment mechanism 51 opens the valve 50 to connect the internal space 10p to the outside, thereby reducing the internal pressure of the high-pressure tank 100.

[0019] The end side nozzle 40 is a member for closing the internal space 10p of the liner 10 on the other end portion 40s side. The end side nozzle 40 is provided on the second dome portion 950 so as to be exposed to both the inside and the outside of the high-pressure tank 100. The shape of the end side nozzle 40 is a cylindrical shape with a part of it being closed in order to close the internal space 10p of the liner 10.

[0020] The fireproof sheet 71 suppresses thermal deterioration of the reinforcing layer 20 and prevents the internal pressure of the high-pressure tank 100 from increasing excessively. In other words, the fireproof sheet 71 is a member for ensuring the fire resistance of the high-pressure tank 100. The fireproof sheet 71 protects the high-pressure tank 100 from a heat source such as a flame, for example, until the temperature of the high-pressure tank 100 increases and the pressure adjustment mechanism 51 operates. The fireproof sheet 71 covers a part of the reinforcing layer 20 in the circumferential direction CD of the high-pressure tank 100. The arrangement, composition, function, and other details of the fireproof sheet 71 will be described later.

[0021] The resin sheet 81 is a sheet-like member having impact resistance to protect the portion of the reinforcing layer 20 that is not covered by the fireproof sheet 71. The resin sheet 81 does not have fire resistance, unlike the fireproof sheet 71. The detailed configuration of the resin sheet 81 will be described later.

[0022] FIG. 2 is a diagram for explaining the positions at which the fireproof sheet 71 and the resin sheet 81 are formed. FIG. 2 shows the high-pressure tank 100 as viewed from the radial outside. FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2. When the high-pressure tank 100 is placed in an orientation such that the axial direction OD along the central axis O coincides with the horizontal direction, the fireproof sheet 71 does not cover a portion of the reinforcing layer 20 including the top T, but covers at least the lower half of the reinforcing layer 20 in the direction of gravity. The top T here refers to the uppermost end of the reinforcing layer 20 in the direction opposite to the direction of gravity (+Y direction) in the orientation.

[0023] In this embodiment, as shown in FIG. 2 and FIG. 3, the fireproof sheet 71 is formed so as to cover up to about two-thirds of the height of the outer surface 20a of the reinforcing layer 20 from the bottom B to the top T in the direction along the gravity direction. The bottom B here is a portion located on the opposite side of the top T, and refers to the lowest end of the reinforcing layer 20 in the gravity direction in the arrangement posture. The resin sheet 81 is formed so as to cover the portion of the outer surface 20a of the reinforcing layer 20 where the fireproof sheet 71 is not formed. The reinforcing layer 20 is covered by either the fireproof sheet 71 or the resin sheet 81. Note that the positions of the fireproof sheet 71 and the resin sheet 81 on the outer surface 20a of the reinforcing layer 20 are not limited thereto. The range of the fireproof sheet 71 on the outer surface 20a of the reinforcing layer 20 may be adjusted according to the outer diameter of the high-pressure tank 100, for example.

[0024] FIG. 4 is a diagram for explaining the configuration of the fireproof sheet 71. In FIG. 4, the reinforcing layer 20 is also illustrated in order to easily understand the positional relationship between the fireproof sheet 71 and the reinforcing layer 20. The fireproof sheet 71 includes a fireproof layer 711, a tank replacement reference layer 721, and an adhesive layer 731, in that order from the radially outer side to the radially inner side. The fireproof sheet 71 is a laminate in which these layers 711, 721, and 731 are laminated and integrally formed. The adhesive layer 731 is adhered to the reinforcing layer 20. The tank replacement reference layer 721 is laminated on the adhesive layer 731. The fireproof layer 711 is laminated on the tank replacement reference layer 721, and forms the outer surface 71a of the high-pressure tank 100.

[0025] The fire-resistant layer 711 has fire resistance. The fire-resistant layer 711 includes expandable graphite C that expands with an increase in temperature. The fire-resistant layer 711 is formed, for example, by adding the expandable graphite C to a resin (hereinafter, resin base P) having a predetermined composition.

[0026] FIG. 5 is a diagram for explaining the configuration of the resin sheet 81. In FIG. 5, the reinforcing layer 20 is also illustrated in order to easily understand the positional relationship between the resin sheet 81 and the reinforcing layer 20. In this embodiment, the resin sheet 81 includes, in order from the radially outer side toward the radially inner side, a protective layer 811 having impact resistance, a tank replacement reference layer 721, and an adhesive layer 731. The composition of the protective layer 811 is a composition obtained by removing the expanded graphite C (FIG. 4) from the fireproof layer 711. The resin sheet 81 is a laminate in which these layers 811, 721, and 731 are laminated and integrally molded. The adhesive layer 731 is adhered to the reinforcing layer 20. The tank replacement reference layer 721 is laminated on the adhesive layer 731. The protective layer 811 is laminated on the tank replacement reference layer 721 and forms the outer surface 81a of the high-pressure tank 100. The function and composition of the resin sheet 81 are not limited to those described above. Resin sheet 81 may be made of other materials as long as it has at least impact resistance to protect reinforcing layer 20. Protective layer 811 may contain other materials such as GFRP (Glass Fiber Reinforced Plastics).

[0027] FIG. 6 is a schematic diagram for explaining the change in shape of the fireproof sheet 71 before and after expansion and the state of the flame. In FIG. 6, the shape (outline) of the fireproof sheet 71 before expansion is shown by a solid line, and the shape of the fireproof sheet 71 after expansion is shown by a dotted line. In FIG. 6, the state of the flame when it is assumed that the fireproof layer 711 does not expand is shown by a solid arrow, and the state of the flame after the fireproof layer 711 expands is shown by a dotted arrow. In this embodiment, the flame is described as approaching the high-pressure tank 100 in the arrangement posture from the bottom B side, that is, from the lower side in the direction of gravity. The case where the flame approaches the high-pressure tank 100 from the lower side in the direction of gravity is, for example, a case where a flame exposure test is performed based on the Global Technical Regulation (GTR). Note that even when a vehicle fire actually occurs, the state of the fireproof sheet 71 and the flame is the same as the content described below. Furthermore, FIG. 6 merely shows a schematic representation of the shape of the fireproof sheet 71 after expansion, and the scales before and after expansion shown in FIG. 6 do not match the actual scales.

[0028] The expandable graphite C starts to expand when it reaches an expansion start temperature (for example, about 150°C or more and about 220°C or less). Therefore, when the high-pressure tank 100 is heated by being exposed to a heat source such as a flame from below, the fireproof layer 711 expands with the temperature rise of the fireproof sheet 71. Specifically, the fireproof layer 711 expands in sequence from the bottom B side close to the flame to the side 100s side located in the middle between the top T and the bottom B in response to the propagation of heat. Then, when the heat from the flame is transmitted to the boundary 78 between the fireproof sheet 71 and the resin sheet 81, the fireproof layer 711 is in a state of being expanded almost uniformly, as shown by the dotted line in FIG. 6. The side 100s refers to the portion where the horizontal plane S including the central axis O intersects with the fireproof sheet 71 in the arrangement posture shown in FIG. 6. The horizontal plane S is a plane parallel to the XZ plane.

[0029] At this time, the tank replacement reference layer 721 and the adhesive layer 731 shown in Fig. 4 are formed so as to integrally follow the shape change of the fireproof layer 711 due to expansion. In other words, the tank replacement reference layer 721 and the adhesive layer 731 each have a degree of ductility that does not break when the fireproof layer 711 expands. Therefore, as shown in Fig. 6, when the temperature of the outer surface 71a side of the high-pressure tank 100 increases, the shape of the entire fireproof sheet 71 changes in response to the expansion of the fireproof layer 711.

[0030] When the outer diameter of the reinforcing layer 20 is 300 mm, the thickness of the fireproof sheet 71 before the expansion of the fireproof layer 711 is, for example, about 1.5 mm. At this time, the thickness of the unexpanded fireproof layer 711 is, for example, about 1.0 mm. The fireproof layer 711 is blended with expanded graphite C such that the volume of the expanded fireproof layer 711 is in the range of 20 to 60 times the initial volume of the fireproof layer 711 before expansion. Note that the thickness of the fireproof sheet 71, the thickness of the fireproof layer 711, the amount of expanded graphite C contained in the fireproof layer 711, and the volume change of the fireproof layer 711 before and after expansion are not limited to the above.

[0031] Assuming that the fireproof layer 711 does not expand, when the bottom B side of the high-pressure tank 100 is exposed to a heat source such as a flame, the flame will easily reach the top T side where the fireproof sheet 71 is not formed, as shown by the solid arrow in FIG. 6. In contrast, in this embodiment, as shown by the dotted arrow in FIG. 6, the fireproof layer 711 expands with an increase in temperature, so that the flame can be moved away from the reinforcing layer 20 side. This can reduce the amount of heat transmitted to the reinforcing layer 20 side. Furthermore, even if the flame spreads from the bottom B side toward the boundary portion 78 side, the expanded fireproof layer 711 acts as a barrier to prevent the flame from reaching the top T side of the high-pressure tank 100. This can ensure the fireproof performance of the entire high-pressure tank 100 without disposing the fireproof sheet 71 on the top T side.

[0032] Since the fire-resistant layer 711 is a layer that forms the outer surface 71a of the high-pressure tank 100, it is preferable that the layers 721, 731, and 20 radially inside the fire-resistant layer 711 can be protected when an external force such as an impact force is applied from the outer surface 71a side of the high-pressure tank 100. Therefore, in this embodiment, the fire-resistant layer 711 further has impact resistance. The impact resistance is realized, for example, by the resin base P contained in the fire-resistant layer 711. The resin base P is made of, for example, polyurethane and polyvinyl chloride. In this way, the fire-resistant layer 711 also has impact resistance, thereby reducing the possibility of the reinforcing layer 20 and the liner 10 being damaged.

[0033] The type of resin constituting the resin base P is not limited to this. The fire-resistant layer 711 is a material that can realize a desired impact resistance performance, and may be formed by adding expanded graphite C to a material other than resin. The fire-resistant sheet 71 may also have a protective layer 811 formed radially outward of the fire-resistant layer 711.

[0034] The tank replacement reference layer 721 shown in Fig. 4 is provided to determine whether or not the reinforcing layer 20 is damaged when an external force such as an impact force is applied from the outer surface 71a of the high-pressure tank 100. The tank replacement reference layer 721 is disposed closer to the reinforcing layer 20 than the fire-resistant layer 711. The tank replacement reference layer 721 is formed, for example, from soft polyvinyl chloride. By forming the tank replacement reference layer 721 from a soft material such as soft polyvinyl chloride, it is possible to prevent cracks from occurring in the tank replacement reference layer 721 when the fire-resistant layer 711 expands.

[0035] The tank replacement reference layer 721 is a layer having a different color from the reinforcing layer 20. The color difference between the tank replacement reference layer 721 and the reinforcing layer 20 may be such that a user can generally distinguish the colors. For example, in the Munsell color system, when colors are distinguished by Munsell values ​​determined by hue, brightness, and saturation, the tank replacement reference layer 721 and the reinforcing layer 20 may differ in at least one of the hue, brightness, and saturation to such an extent that the colors can be distinguished.

[0036] In the case where the color of the reinforcing layer 20 is a chromatic color, if the color of the tank replacement reference layer 721 is a chromatic color, for example, the tank replacement reference layer 721 is formed to have a color (non-similar color) that is not similar to the color of the reinforcing layer 20 in terms of the hue in the Munsell value. Non-similar colors refer to colors with a hue difference of 1.0 or more, more preferably 3.0 or more, in the 20-color hue circle (modified Munsell hue circle) adopted in the JIS standard (JIS Z 8102). This allows the user to more clearly distinguish between the tank replacement reference layer 721 and the reinforcing layer 20.

[0037] When the reinforcing layer 20 is a chromatic color and the tank replacement reference layer 721 is an achromatic color, it is preferable to form the tank replacement reference layer 721 so that the brightness difference in Munsell value between the tank replacement reference layer 721 and the reinforcing layer 20 is 5.0 or more. This allows the user to more clearly distinguish between the tank replacement reference layer 721 and the reinforcing layer 20.

[0038] When the reinforcing layer 20 is achromatic and the tank replacement reference layer 721 is chromatic, it is preferable that the tank replacement reference layer 721 is formed to have a color with a Munsell saturation of 5.0 or more in any hue. This allows the user to more clearly distinguish the tank replacement reference layer 721 from the reinforcing layer 20.

[0039] When the color of the reinforcing layer 20 is black or gray, and the color of the tank replacement reference layer 721 is achromatic, it is preferable to form the tank replacement reference layer 721 so that the brightness difference in Munsell value between the tank replacement reference layer 721 and the reinforcing layer 20 is 5.0 or more. This allows the user to more clearly distinguish the tank replacement reference layer 721 from the reinforcing layer 20. Here, black or gray is, for example, an achromatic color with a brightness of 3.0 or less in Munsell value. When the color of the reinforcing layer 20 is gray (for example, Munsell value N2.0), for example, the color of the tank replacement reference layer 721 is white (for example, Munsell value N9.0).

[0040] In this way, by providing the tank replacement reference layer 721, which has a different color from the reinforcing layer 20, radially outward from the reinforcing layer 20, when the outer surface 71a of the high-pressure tank 100 is damaged, it is possible to visually determine from the appearance whether the damaged area has reached the reinforcing layer 20. This makes it easy to determine whether the reinforcing layer 20 is scratched.

[0041] The color difference between the tank replacement reference layer 721 and the reinforcing layer 20 may be distinguished by other methods (for example, RGB values). The colors of the tank replacement reference layer 721 and the reinforcing layer 20 are not limited to those described above. The color of the tank replacement reference layer 721 may be the color of the material itself that constitutes the tank replacement reference layer 721, or may be a color that is exhibited by coloring with a coloring agent or the like.

[0042] The adhesive layer 731 shown in FIG. 4 is a layer for adhering the fireproof sheet 71 to the outer surface 20a of the reinforcing layer 20. The adhesive layer 731 is disposed closer to the reinforcing layer 20 than the tank exchange reference layer 721. The adhesive layer 731 has a first adhesive surface 731a for adhering the fireproof sheet 71 to the outer surface 20a of the reinforcing layer 20, and a second adhesive surface 731b for adhering the adhesive layer 731 to the tank exchange reference layer 721. The adhesive layer 731 is, for example, a sheet-like double-sided tape. When the thickness of the fireproof sheet 71 before the fireproof layer 711 expands is about 1.5 mm, the tank exchange reference layer 721 and the adhesive layer 731 are formed so that the total thickness of the two layers 721, 731 is, for example, about 0.5 mm. In this way, the fireproof sheet 71 can be easily attached to the outer surface 20a of the reinforcing layer 20. The thicknesses of the tank exchange reference layer 721 and the adhesive layer 731 are not limited to this. Furthermore, the reinforcing layer 20 and the fireproof sheet 71 may be bonded together by other methods such as with an adhesive.

[0043] According to the first embodiment, when the temperature of the outer surface 71a of the high-pressure tank 100 rises, the fire-resistant layer 711 expands, thereby preventing flames from reaching the top T of the high-pressure tank 100 and reducing the amount of heat transmitted to the reinforcing layer 20. This ensures fire resistance in the entire high-pressure tank 100 without covering the entire outer surface 20a of the reinforcing layer 20 with the fire-resistant sheet 71 having fire resistance.

[0044] Moreover, according to the first embodiment, the portion of the outer surface 20a of the reinforcing layer 20 on which the fireproof sheet 71 is not formed is covered with the resin sheet 81 that does not contain the expanded graphite C. This makes it possible to reduce costs while ensuring the fireproof performance and impact resistance of the high-pressure tank 100.

[0045] B. Second embodiment: FIG. 7 is a schematic diagram showing the configuration of the high-pressure tank 100 in the second embodiment. As in FIG. 6, FIG. 7 shows the cross section of the high-pressure tank 100 viewed from the -X direction side. FIG. 7 shows the fireproof sheet 71 and the auxiliary fireproof sheet 72 before expansion. In addition, in FIG. 7, the state of the flame when it is assumed that the fireproof layer 711 does not expand is shown by a solid arrow, and the state of the flame after the fireproof layer 711 expands is shown by a dotted arrow. Furthermore, in FIG. 7, the direction in which the fireproof sheet 71 and the auxiliary fireproof sheet 72 expand during a temperature rise is shown by a thick arrow. Note that, in this embodiment, the flame will be described as approaching the high-pressure tank 100 in the arrangement posture from the bottom B side, that is, from the lower side in the gravity direction.

[0046] In the above-described first embodiment, the fire resistance of the entire high-pressure tank 100 is ensured by a fireproof sheet 71 that covers a portion of the reinforcing layer 20. In contrast, in this embodiment, the high-pressure tank 100 further includes an auxiliary fireproof sheet 72. That is, part of the method for ensuring the fire resistance of the entire high-pressure tank 100 differs from that of the first embodiment (FIG. 6). The other configurations are the same as those of the first embodiment. Therefore, the same reference numerals are used for the same configurations as those of the first embodiment, and the description thereof will be omitted.

[0047] The auxiliary fireproof sheet 72 is a member for further improving the fire resistance of the high-pressure tank 100. The auxiliary fireproof sheet 72 has a fireproof layer 711. When the auxiliary fireproof sheet 72 is in the position shown in FIG. 7, the auxiliary fireproof sheet 72 is disposed on the outer periphery side of the reinforcing layer 20 so as to straddle the horizontal plane S including the central axis O. In FIG. 7, the horizontal plane S is a plane parallel to the XZ plane. In this embodiment, the auxiliary fireproof sheet 72 has an elongated shape extending in the circumferential direction CD. In the example shown in FIG. 7, the boundary portion 78 is located on the top T side of the horizontal plane S including the central axis O. Therefore, the auxiliary fireproof sheet 72 is formed so as to cover a part of the fireproof sheet 71 and a part of the resin sheet 81.

[0048] In this embodiment, the auxiliary fireproof sheet 72 has the same laminated structure as the fireproof sheet 71 (FIG. 4). The auxiliary fireproof sheet 72 is different from the fireproof sheet 71 in the formation position and formation range in the high-pressure tank 100. In other words, the thickness of the auxiliary fireproof sheet 72 is the same as the thickness of the fireproof sheet 71. Therefore, among the portions where the fireproof sheet 71 is arranged, the portion where the auxiliary fireproof sheet 72 is arranged has a fireproof layer 711 twice as thick as the portion where the auxiliary fireproof sheet 72 is not arranged. Note that the configuration and thickness of the auxiliary fireproof sheet 72 are not limited to this. The auxiliary fireproof sheet 72 may have a different configuration from the fireproof sheet 71 as long as it has the fireproof layer 711 containing the expanded graphite C.

[0049] According to the second embodiment, the auxiliary fireproof sheet 72 having the fireproof layer 711 is disposed on the outer surface 71a of the fireproof sheet 71 so as to straddle the horizontal plane S including the central axis O when in the disposition posture shown in FIG. 7. That is, the auxiliary fireproof sheet 72 is disposed on the side portion 100s. In this way, even if the expansion near the boundary portion 78 is delayed compared to the bottom B side in the process in which the fireproof layer 711 expands in sequence from the bottom B side close to the flame through the side portion 100s toward the boundary portion 78, the possibility of the flame reaching the top portion T can be reduced. That is, by increasing the thickness of the laminated portion where the fireproof sheet 71 and the auxiliary fireproof sheet 72 are laminated more than other portions, the side portion 100s can be expanded further when the high-pressure tank 100 is heated. This further reduces the amount of heat transmitted to the reinforcing layer 20 side, and the side portion 100s expands further, thereby further preventing the flame from reaching the top portion T side. Therefore, the fire resistance of the entire high-pressure tank 100 can be improved.

[0050] According to the second embodiment, the fireproof sheet 71 and the auxiliary fireproof sheet 72 have the same configuration. Therefore, the fireproof sheet 71 and the auxiliary fireproof sheet 72 can be manufactured by the same manufacturing process. This can reduce the cost and man-hours required to manufacture the auxiliary fireproof sheet 72.

[0051] C. Third embodiment: FIG. 8 is a schematic diagram showing the configuration of the high-pressure tank 100 in the third embodiment. FIG. 8 shows the cross section of the high-pressure tank 100 viewed from the -X direction side, as in FIG. 6. FIG. 8 shows the fireproof sheet 71 before expansion. In addition, in FIG. 8, the state of the flame when it is assumed that the fireproof layer 711 does not expand is shown by a solid arrow, and the state of the flame after the fireproof layer 711 expands is shown by a dotted arrow. Furthermore, in FIG. 8, the direction in which the fireproof sheet 71 expands during a temperature rise is shown by a thick arrow. Note that, in this embodiment, the flame will be described as approaching the high-pressure tank 100 in the arrangement posture shown in FIG. 8 from the bottom B side, that is, from the lower side in the gravity direction.

[0052] In the second embodiment, the fire resistance of the entire high-pressure tank 100 is improved by the auxiliary fireproof sheet 72. In contrast, in this embodiment, the high-pressure tank 100 is provided with a fireproof member 75 instead of the auxiliary fireproof sheet 72. In other words, part of the method of ensuring the fire resistance of the entire high-pressure tank 100 differs from the first embodiment (FIG. 6) and the second embodiment (FIG. 7). The other configurations are the same as those in the first embodiment. Therefore, the same reference numerals are used for the same configurations as those in the first embodiment, and the description thereof will be omitted.

[0053] The fireproof member 75 is a member for further improving the fireproof performance of the high-pressure tank 100. The fireproof member 75 has fireproof performance but does not contain expanded graphite C. The fireproof member 75 is, for example, a coating film formed by applying a fireproof paint to a part of the outer surface 20a of the reinforcing layer 20. The fireproof member 75 is applied, for example, before covering the outer surface 20a of the reinforcing layer 20 with either the fireproof sheet 71 or the resin sheet 81. Then, after the coating film of the fireproof paint is formed, the fireproof sheet 71 and the resin sheet 81 are respectively arranged.

[0054] In the arrangement posture shown in FIG. 8, the fireproof member 75 is disposed between the reinforcing layer 20 and the fireproof sheet 71 so as to straddle the horizontal plane S including the central axis O. Specifically, the fireproof member 75 is disposed between the outer surface 20a of the reinforcing layer 20 and the first adhesive surface 731a (FIG. 4) of the adhesive layer 731. In FIG. 8, the horizontal plane S is a plane parallel to the XZ plane. In the example shown in FIG. 8, the boundary portion 78 is located on the apex T side of the horizontal plane S including the central axis O. Therefore, a part of the fireproof member 75 is disposed between the outer surface 20a of the reinforcing layer 20 and the resin sheet 81.

[0055] According to the third embodiment, in the arrangement posture shown in Fig. 8, the fireproof member 75 is arranged between the fireproof sheet 71 and the reinforcing layer 20 so as to straddle the horizontal plane S including the central axis O. In this way, even if the expansion of the boundary portion 78 side of the fireproof layer 711 away from the bottom B side exposed to a heat source such as a flame is delayed compared to the bottom B side, the amount of heat transferred to the reinforcing layer 20 side near the boundary portion 78 can be reduced. In other words, by arranging the fireproof member 75 between the reinforcing layer 20 and the fireproof sheet 71 near the boundary portion 78, the fire resistance of the entire high-pressure tank 100 can be improved.

[0056] According to the third embodiment, the fire-resistant member 75 is formed of a fire-resistant paint. In this way, even if the fire-resistant member 75 is disposed between the reinforcing layer 20 and the fire-resistant sheet 71, the fire resistance of the high-pressure tank 100 can be improved without significantly increasing the weight of the high-pressure tank 100.

[0057] According to the third embodiment, the fire-resistant member 75 is a coating film formed by applying a fire-resistant paint to a part of the outer surface 20a of the reinforcing layer 20. In this way, the fire-resistant member 75 can be easily formed.

[0058] D. Other embodiments: D-1. Other embodiment 1: In the second embodiment, as shown in FIG. 7, the fireproof sheet 71 is formed so as to cover up to about two-thirds of the height of the outer surface 20a of the reinforcing layer 20 from the bottom B to the top T in the direction along the gravity direction. At this time, the auxiliary fireproof sheet 72 is formed so as to cover a part of the fireproof sheet 71 and a part of the resin sheet 81 so as to straddle the horizontal plane S. In contrast, for example, when the fireproof sheet 71 is formed so as to cover up to about four-fifths of the height of the outer surface 20a of the reinforcing layer 20 from the bottom B to the top T in the direction along the gravity direction, the auxiliary fireproof sheet 72 may be formed so as to cover a part of the fireproof sheet 71 without covering the resin sheet 81 so as to straddle the horizontal plane S. In other words, the auxiliary fireproof sheet 72 may be formed in an area including the side portion 100s.

[0059] In this configuration, by increasing the thickness of the side portion 100s, it is possible to reduce the possibility that the flame will reach the top portion T. As a result, even if the auxiliary fire-resistant sheet 72 is not formed at the boundary portion 78, the auxiliary fire-resistant sheet 72 can improve the fire resistance of the entire high-pressure tank 100.

[0060] D-2. Other embodiment 2: In the third embodiment, as shown in Fig. 8, the fire-resistant member 75 is a coating formed by a fire-resistant paint. In contrast, the fire-resistant member 75 may be formed by a material other than the fire-resistant paint. The fire-resistant member 75 may be formed by a material such as polyethylene having fire resistance or flame retardancy. Even in such a form, the fire-resistant member 75 can improve the fire resistance of the entire high-pressure tank 100.

[0061] D-3. Other embodiment 3: The tank replacement reference layer 721 may further be a layer having a different color from both the reinforcing layer 20 and the fire-resistant layer 711. In this case, when the outer surface 71a of the high-pressure tank 100 is damaged, it is possible to easily determine to which layer 20, 711, 721 the damage has reached: the reinforcing layer 20, the tank replacement reference layer 721, or the fire-resistant layer 711.

[0062] The present disclosure is not limited to the above-mentioned embodiment, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features of the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention can be appropriately replaced or combined to solve some or all of the above-mentioned problems or to achieve some or all of the above-mentioned effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0063] 10...liner, 10d...opening, 10p...internal space, 10r...tip portion, 20...reinforcing layer, 20a...outer surface, 30...valve side nozzle, 30r...one end portion, 40...end side nozzle, 40s...other end portion, 50...valve, 51...pressure adjustment mechanism, 71...fireproof sheet, 71a, 81a...outer surface of high-pressure tank, 72...auxiliary fireproof sheet, 75...fireproof member, 78...boundary portion, 81...resin sheet, 9 0...container body, 100...high pressure tank, 100s...side, 711...fireproof layer, 721...tank exchange reference layer, 731...adhesive layer, 731a...first adhesive surface, 731b...second adhesive surface, 811...protective layer, 910...main body, 930...first dome portion, 950...second dome portion, B...bottom, C...expanded graphite, CD...circumferential direction, O...center axis, OD...axial direction, P...resin base, S...horizontal surface, T...top

Claims

1. A high-pressure tank, a liner having a central axis; A reinforcing layer covering an outer periphery of the liner; a fireproof sheet covering a part of the reinforcing layer in the circumferential direction of the high-pressure tank, the fireproof sheet having a fireproof layer containing expandable graphite that expands due to a rise in temperature; The fireproof sheet is When the high-pressure tank is placed in an orientation such that an axial direction along the central axis coincides with a horizontal direction, a part of the reinforcing layer including a top portion is not covered, and at least a lower half portion of the reinforcing layer in the direction of gravity is covered, The high-pressure tank further includes an auxiliary fireproof sheet disposed on an outer circumferential side of the reinforcing layer, the auxiliary fireproof sheet being disposed so as to straddle a horizontal plane including the central axis when in the disposed position, A high-pressure tank, wherein the auxiliary fire-resistant sheet has the fire-resistant layer.

2. A high-pressure tank, a liner having a central axis; A reinforcing layer covering an outer periphery of the liner; a fireproof sheet covering a part of the reinforcing layer in the circumferential direction of the high-pressure tank, the fireproof sheet having a fireproof layer containing expandable graphite that expands due to a rise in temperature; The fireproof sheet is When the high-pressure tank is placed in an orientation such that an axial direction along the central axis coincides with a horizontal direction, a part of the reinforcing layer including a top portion is not covered, and at least a lower half portion of the reinforcing layer in the direction of gravity is covered, The high-pressure tank further includes a refractory member that does not contain the expanded graphite, A high-pressure tank, wherein the fire-resistant member, when in the arranged posture, is positioned between the reinforcing layer and the fire-resistant sheet so as to straddle a horizontal plane including the central axis.

3. 3. The high-pressure tank according to claim 2, A high-pressure tank, wherein the fire-resistant member is formed of a fire-resistant paint.

4. A high-pressure tank, a liner having a central axis; A reinforcing layer covering an outer periphery of the liner; a fireproof sheet covering a part of the reinforcing layer in the circumferential direction of the high-pressure tank, the fireproof sheet having a fireproof layer containing expandable graphite that expands due to a rise in temperature; The fireproof sheet is When the high-pressure tank is placed in an orientation such that an axial direction along the central axis coincides with a horizontal direction, a part of the reinforcing layer including a top portion is not covered, and at least a lower half portion of the reinforcing layer in the direction of gravity is covered, The fireproof sheet further comprises a tank exchange reference layer; The tank exchange reference layer is The layer has a different color from the reinforcing layer, A high-pressure tank arranged on the reinforcing layer side of the fire-resistant layer.

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