Vehicle-mounted liquid hydrogen tank and method of manufacturing the same

Abstract

The present application relates to a kind of vehicle-mounted liquid hydrogen tank and its manufacturing method.Vehicle-mounted liquid hydrogen tank (10) has: inner tank (12), stores liquid hydrogen;Outer tank (14), contains the inner tank (12);And heat insulating member (16), arranged in the gap between the inner tank (12) and the outer tank (14), i.e. heat insulation gap (18), the inner tank (12) is kept with the state of being separated from the inner surface of the outer tank (14), the heat insulation gap (18) has the vacuum region (17) not filled with the heat insulating member (16) and the area of the inner tank (12) supported by the heat insulating member (16) by filling the heat insulating member (16).

Description

[0001] Cross-reference of related applications

[0002] This application claims priority to Japanese Patent Application No. 2022-107641, filed on July 4, 2022, the entire contents of which, including the description, claims, drawings and abstract, are incorporated herein by reference. Technical Field

[0003] This specification discloses a vehicle-mounted liquid hydrogen tank for storing liquid hydrogen and its manufacturing method. Background Technology

[0004] Previously, vehicle-mounted liquid hydrogen tanks for storing hydrogen in a liquid state were known. For example, Patent Document 1 discloses a technique of arranging a metal inner tank inside an outer tank made of reinforced fiber material and storing liquid hydrogen in the inner tank. In Patent Document 1, a vacuum insulation layer is formed between the outer tank and the inner tank. In addition, a buffer is partially arranged between the outer tank and the inner tank, and the inner tank is suspended and held inside the outer tank by the buffer. According to this vehicle-mounted liquid hydrogen tank, since heat transfer to the inner tank is hindered by the vacuum insulation layer, the interior of the inner tank can be kept at a low temperature, and the vaporization of liquid hydrogen can be suppressed.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-066426

[0008] However, in the structure of Patent Document 1, the inner tank is suspended and held by a locally configured buffer. In this case, if a strong impact is applied to the vehicle-mounted liquid hydrogen tank, the following possibilities exist: damage or deformation of the buffer, collision between the inner and outer tanks, and deterioration or breakage of the inner tank. Furthermore, in the event of deterioration or breakage of the inner tank, various problems such as hydrogen leakage may occur.

[0009] Therefore, this specification discloses an on-board liquid hydrogen tank capable of storing liquid hydrogen more stably and a method for manufacturing the same. Summary of the Invention

[0010] The vehicle-mounted liquid hydrogen tank disclosed in this specification is characterized by comprising: an inner tank for storing liquid hydrogen; an outer tank for housing the inner tank; and a heat insulation member disposed in the gap between the inner tank and the outer tank, i.e., a heat insulation gap, which holds the inner tank apart from the inner surface of the outer tank. The heat insulation gap has a vacuum area unfilled by the heat insulation member and an area in which the inner tank is supported by the surface of the heat insulation member by filling the heat insulation member.

[0011] In a vacuum region, heat is not transferred in any form other than radiation. Therefore, by establishing a vacuum region, the insulation performance of the inner tank can be maintained at a high level. On the other hand, in the case of a vacuum region alone, the inner tank may collide with the outer tank during a vehicle collision. However, by providing an area in the insulation gap, as described above, where the inner tank is supported by the surface of the insulation element filled with insulation material, such a collision between the inner tank and the outer tank can be prevented. In other words, according to the above structure, it is possible to maintain high insulation performance while preventing the inner tank from colliding with the outer tank during a vehicle collision. Furthermore, this effectively prevents deformation and damage to the inner tank, thus enabling more stable storage of liquid hydrogen.

[0012] In this case, the insulation component may include a super-insulating component formed by stacking one or more heat shielding layers made of metal sheets and one or more spacer layers made of fiber materials, wherein the insulation gap is evacuated when the insulation component is configured.

[0013] By using superinsulated components, the temperature of liquid hydrogen can be prevented from rising more effectively.

[0014] Alternatively, the heat insulation component may be housed in a sealed bag, with both the interior of the sealed bag and the heat insulation gap being evacuated.

[0015] This design simplifies the manufacturing of liquid hydrogen tanks.

[0016] Alternatively, the outer can may have a rupture disc that breaks when the internal pressure of the outer can reaches or exceeds a predetermined allowable pressure, thereby opening the interior of the outer can to the atmosphere.

[0017] This design prevents the internal pressure of the outer tank from becoming too high, thus improving the safety of the liquid hydrogen tank.

[0018] Alternatively, the inner tank may have a shape with a flat portion.

[0019] By placing a heat-insulating element in the gap between the outer and inner tanks, the internal pressure of the inner tank is dispersed to the outer tank and the heat-insulating element, thereby increasing the maximum allowable pressure of the inner tank. Furthermore, even if the inner tank deforms, it does not directly contact the outer tank, thus maintaining its insulation properties. Therefore, the inner tank can be made into a shape with a flat portion.

[0020] Alternatively, it may also include a booster pump that pressurizes the liquid hydrogen stored in the inner tank and outputs it to the outside, with a collection section formed at the bottom of the inner tank that slopes downward and is inserted into the lower end of the booster pump.

[0021] By designing the structure in this way, the pressure of the accumulated liquid hydrogen can be kept low, and the maximum allowable pressure required for the inner tank can also be kept low. Furthermore, this reduces the cost and weight associated with the hydrogen tank.

[0022] The method for manufacturing a vehicle-mounted hydrogen tank disclosed in this specification is characterized in that, after a heat insulation component containing fibrous material is housed in a sealed bag, the inside of the sealed bag is evacuated, an inner tank containing liquid hydrogen is placed inside an outer tank, and the sealed bag is placed in the gap between the inner tank and the outer tank, i.e., the heat insulation gap, and the heat insulation gap is evacuated.

[0023] By pre-vacuuming the sealed bag, the insulation is compressed. Therefore, the insulation can be easily positioned within the gap between the outer and inner tanks. Furthermore, if the insulation gap is evacuated after the insulation is in place, the pressure difference between the inside and outside of the sealed bag decreases, causing the insulation to expand and fill the gap. In other words, based on the above structure, a liquid hydrogen tank capable of storing liquid hydrogen more stably can be easily manufactured.

[0024] Invention Effects

[0025] Based on the technology disclosed in this specification, liquid hydrogen can be stored more stably. Attached Figure Description

[0026] Figure 1 This is a 3D view of the vehicle-mounted liquid hydrogen tank.

[0027] Figure 2 This is a cross-sectional view of the vehicle-mounted liquid hydrogen tank.

[0028] Figure 3 This is a schematic diagram illustrating the scenario of a collision involving an onboard liquid hydrogen tank.

[0029] Figure 4 This is a schematic diagram illustrating the manufacturing process of an onboard liquid hydrogen tank.

[0030] Figure 5A This is a schematic diagram showing the state of the insulation component before the insulation gap is evacuated.

[0031] Figure 5B This is a schematic diagram showing the state of the insulation component after the insulation gap has been evacuated.

[0032] Figure 6 This is a flowchart illustrating the manufacturing process of the vehicle-mounted liquid hydrogen tank.

[0033] Figure 7 This is a schematic diagram illustrating another example of an onboard liquid hydrogen tank.

[0034] Figure 8 This is a schematic diagram showing a comparative example of an onboard liquid hydrogen tank.

[0035] Figure 9 This is a schematic diagram illustrating the collision scenario of a comparative example vehicle-mounted liquid hydrogen tank. Detailed Implementation

[0036] The structure of the liquid hydrogen tank 10 (hereinafter referred to as "hydrogen tank 10") will be described below with reference to the accompanying drawings. Figure 1 This is a 3D view of hydrogen tank 10. Additionally, Figure 2 This is a cross-sectional view of the hydrogen tank 10. The hydrogen tank 10 is mounted on a vehicle and stores hydrogen in a liquid state. The type of vehicle equipped with this hydrogen tank 10 is not particularly limited, but it may be mounted on a fuel cell vehicle or a hydrogen engine vehicle, for example. In the following description, the hydrogen tank 10 mounted on a hydrogen engine vehicle equipped with a direct injection hydrogen engine that injects high-pressure hydrogen into the engine cylinders will be used as an example.

[0037] Hydrogen tank 10 stores hydrogen in a liquid state. The pressure of the stored liquid hydrogen is the same as or slightly higher than atmospheric pressure, for example, below 1 MPa. In addition, hydrogen tank 10 stores the liquid hydrogen at a temperature that is sufficiently low than its boiling point (-252.9°C at atmospheric pressure).

[0038] like Figure 1 As shown, the hydrogen tank 10 is shaped like a sandbag, having a cylindrical main body 10a and wall panel portions 10b blocking the axial ends of the main body 10a. The wall panel portions 10b are dome-shaped and formed by curved surfaces. Furthermore, a collection section 20, partially recessed, is provided at the bottom of the hydrogen tank 10. The collection section 20 is composed of a cylinder and dome-shaped portions blocking the ends of the cylinder. It is evident from the description so far that virtually all of the constituent surfaces of the hydrogen tank 10 are formed by curved surfaces. By adopting this structure, the pressure distribution applied to the hydrogen tank 10 can be made nearly uniform.

[0039] A liquid hydrogen filling port 26 and a hydrogen return port 28 are installed on the side of the hydrogen tank 10. The liquid hydrogen filling port 26 is a port for receiving the supply of liquid hydrogen and is connected to the inner tank 12, which will be described later. The hydrogen return port 28 is a port for drawing the hydrogen gas (so-called vaporized gas) that has been vaporized by natural heat input during the supply of liquid hydrogen back to the supply source side. This hydrogen return port 28 is also connected to the inner tank 12.

[0040] Furthermore, the top of the hydrogen tank 10 is equipped with multiple ports, including a pump port 24 and an evaporation port 25. It should be noted that... Figure 1 Only pump port 24 and evaporator port 25 are shown in the diagram; other ports are omitted. Pump port 24 supplies power to pump 22 (see reference). Figure 2The port through which the cylinder block is inserted is the port that communicates with the inner tank 12. Pump 22 is a booster pump that pressurizes and pumps up the liquid hydrogen stored in the hydrogen tank 10 upon request from the hydrogen engine. The pressure of the pressurized liquid hydrogen is, for example, 5 MPa to tens of MPa. The high-pressure liquid hydrogen pumped up by pump 22 is vaporized and injected directly into the engine cylinder as high-pressure hydrogen gas. That is, in this example, only the amount of hydrogen required in the hydrogen engine is pressurized and extracted. By adopting this structure, the pressure of the liquid hydrogen stored in the hydrogen tank 10 can be kept low. As a result, the maximum allowable pressure of the hydrogen tank 10 can be kept low, and the cost and weight associated with the hydrogen tank 10 can be reduced.

[0041] It should be noted that the suction port for liquid hydrogen in the suction tank of pump 22 is located in the collection section 20. With this structure, even if the remaining liquid hydrogen in the tank becomes less, the liquid hydrogen can still be pumped up by pump 22.

[0042] Evaporation port 25 is used to release hydrogen gas, the so-called evaporated gas, produced by the vaporization of liquid hydrogen due to natural heat input, to the outside of the tank. This evaporation port 25 is connected to the inner tank 12. Additionally, an evaporation valve 29 (see reference) is connected to evaporation port 25. Figure 2 The evaporation valve 29 opens when the internal pressure of the hydrogen tank 10 (more precisely, the inner tank 12) reaches or exceeds the specified release pressure, releasing the evaporated gas to the outside of the tank.

[0043] like Figure 2 As shown, such a hydrogen tank 10 has an inner tank 12 for storing liquid hydrogen and an outer tank 14 for housing the inner tank 12. The inner tank 12 is made of a metal that does not produce low-temperature brittleness, such as stainless steel, especially 18-8 stainless steel. As described above, the inner tank 12 is sandbag-shaped with a collection section 20 at the bottom. The inner tank 12 is designed such that its maximum allowable pressure is approximately 2 to 5 times the aforementioned release pressure.

[0044] The outer can 14 is shaped by offsetting the inner can 12 outwards. Like the inner can 12, the outer can 14 is made of a metal without low-temperature brittleness, such as stainless steel. A heat insulation gap 18 of a predetermined thickness is provided between the outer can 14 and the inner can 12. The thickness of this heat insulation gap 18 remains approximately constant, almost unchanged depending on the location.

[0045] The insulation gap 18 is partially filled with the insulation element 16, and the insulation gap 18 is evacuated. Therefore, the insulation gap has a vacuum region 17 without the insulation element 16 and a region filled with the insulation element 16, with the inner tank 12 supported by the surface of the insulation element 16. The insulation element 16 is a component that impedes heat transfer from the outside to the inner tank 12 and holds the inner tank 12 separated from the outer tank 14. It should be noted that, in this specification, "filling" means that the insulation element 16 is positioned in the insulation gap 18 in such a way that it contacts both the inner tank 12 and the outer tank 14.

[0046] The structure of the insulation element 16 is not particularly limited as long as it has sufficient thermal insulation performance. In this example, a super-insulating element 34 is used as the insulation element 16. The super-insulating element 34 is constructed by stacking one or more thermal shielding layers 30 and one or more spacer layers 32. The thermal shielding layer 30 is a layer that prevents heat radiation, and is made of, for example, sheet metal (e.g., aluminum). In addition, the spacer layer 32 is a layer that prevents heat transfer, and is made of fibrous material, such as glass wool. The average thermal conductivity of such a super-insulating element 34 is 1×10⁻⁶. -6 Below cal / sec.cm℃.

[0047] The heat insulation element 16 and the heat insulation gap 18 (and consequently the vacuum region 17) are both evacuated. By evacuating, heat transfer to the inner tank 12 is effectively prevented. Furthermore, liquid hydrogen can be stored at a low temperature. A shut-off valve 36 is provided on the outer tank 14, which is connected to the suction pump (not shown) during evacuation and is closed after evacuation.

[0048] In addition, a rupture disc 38 is installed on the outer tank 14. The rupture disc 38 is broken when the internal pressure of the outer tank 14 exceeds the specified allowable pressure, connecting the heat insulation gap 18 to the external space. By installing this rupture disc 38, the internal pressure of the outer tank 14 can be prevented from becoming too high, thus ensuring the safety of the hydrogen tank 10 more reliably.

[0049] As is evident from the description so far, in this example, the gap between the inner tank 12 and the outer tank 14, i.e., the insulation gap 18, is partially filled with an insulation element 16. The reason for this structure will be explained by comparison with a comparative example. Figure 8 , Figure 9 This is a schematic diagram of the comparative example hydrogen tank 10*.

[0050] In the comparative example hydrogen tank 10*, such as Figure 8As shown, the inner tank 12 is suspended and held inside the outer tank 14 by a connecting member 40. The connecting member 40 is a component that connects the inner tank 12 and the outer tank 14, and is made of, for example, resin. The thermal insulation gap 18 between the inner tank 12 and the outer tank 14 is not provided with a thermal insulation member 16, but is evacuated, providing high thermal insulation. This hydrogen tank 10* is mounted on a vehicle. In this case, if the vehicle collides with an obstacle and applies a strong impact to the hydrogen tank 10*, then... Figure 9 As shown, structural component 40 may sometimes break. In this case, due to gravity and inertia, the inner tank 12 and outer tank 14 collide violently, and the inner tank 12 may break. If the inner tank 12 breaks, the accumulated hydrogen will leak out, causing various problems.

[0051] On the other hand, in this example, a heat insulation member 16 is partially provided around the inner tank 12, and a portion of the outer surface of the inner tank 12 contacts the heat insulation member 16. The thickness of the heat insulation member 16 is greater than the thickness of the heat insulation gap 18 under no-load conditions (i.e., when the pressure difference between the inside and outside of the heat insulation member 16 is approximately zero). Therefore, the heat insulation member 16 is tightly attached to both the inner tank 12 and the outer tank 14, holding the inner tank 12 in a state separated from the outer tank 14.

[0052] In this structure, even if the vehicle collides with an obstacle, the inner tank 12 remains separated from the outer tank 14, thus reducing the impact applied to the inner tank 12. Figure 3 This is a schematic diagram illustrating the situation of hydrogen tank 10 during a collision. (As shown) Figure 3 As shown, in this example, the inner tank 12 may sometimes move slightly inside the outer tank 14 due to the impact of a collision. However, since there is a heat insulation element 16 between the outer tank 14 and the inner tank 12, the inner tank 12 remains separated from the outer tank 14. Therefore, collisions between the inner tank 12 and the outer tank 14 can be effectively prevented. As a result, damage to the inner tank 12 and hydrogen leakage can be prevented more reliably. In other words, according to this example, hydrogen can be stored more stably. In addition, in this example, a vacuum region 17 without heat insulation element 16 is provided in the heat insulation gap 18. In the vacuum region 17, heat is not transferred in a form other than radiation. By locally providing this vacuum region 17, the heat insulation of the inner tank 12 can be maintained at a higher level.

[0053] like Figure 4 As shown, the outer tank 14 is constructed by welding together multiple outer tank pieces 50a and 50b. For example, the outer tank 14 is constructed by welding together a cylindrical main body piece 50a and a wall plate piece 50b that blocks the end of the main body piece 50a. During the manufacture of the hydrogen tank 10, the outer tank pieces 50 are arranged around the inner tank 12, and a heat insulation member 16 is arranged between the outer tank pieces 50 and the inner tank 12. The outer tank pieces 50 are then welded together. Furthermore, if the outer tank 14 is formed by welding, the heat insulation gap 18 is evacuated.

[0054] Here, as described above, the thickness of the heat insulation element 16 is greater than the thickness of the heat insulation gap 18 under no-load conditions. Therefore, when the heat insulation element 16 is arranged between the inner tank 12 and the outer tank sheet 50 during the manufacturing process of the hydrogen tank 10, as... Figure 4 As shown, the inner can 12 or the outer can sheet 50 is deformed by the heat insulation member 16, and the final shape of the inner can 12 or the outer can 14 is sometimes unsuitable. In addition, it is difficult to weld the outer can sheet 50 properly when it is deformed.

[0055] Therefore, in this example, during the manufacture of the hydrogen tank 10, the heat insulation component 16 is pre-enclosed in the sealed bag 44, and the sealed bag 44 is evacuated. For details, see [link to relevant documentation]. Figure 5A , Figure 5B To explain. Figure 5A , Figure 5B This is a schematic diagram showing the manufacturing process of the hydrogen tank 10.

[0056] like Figure 5A As shown, and as described above, the insulation element 16 is housed in a sealed bag 44. This sealed bag 44 is pre-evacuated. During the manufacture of the hydrogen tank 10, this sealed bag 44 is positioned in the insulation gap 18 between the inner tank 12 and the outer tank sheet 50. During the stage before welding of the outer tank sheet 50, the insulation gap 18 is not evacuated. Therefore, at this point in time, the insulation element 16 is pressed and compressed by atmospheric pressure. As a result, during the stage before welding of the outer tank sheet 50, as... Figure 5A As shown, the heat insulation element 16 is sufficiently thin compared to the heat insulation gap 18. Therefore, even with the heat insulation element 16 positioned in the heat insulation gap 18, the inner can 12 or the outer can sheet 50 will not deform due to pressure from the heat insulation element 16. It should be noted that, at this time, the sealing bag 44 can also be temporarily bonded to the inner can 12 or the outer can sheet 50 to prevent the sealing bag 44 from moving within the heat insulation gap 18.

[0057] If the insulation element 16 is properly configured, the operator welds the outer can sheets 50 together to form the outer can 14. After forming the outer can 14, the operator evacuates the insulation gap 18. This reduces the pressure difference between the inside and outside of the sealed bag 44, eliminating compression of the insulation element 16. Furthermore, as... Figure 5B As shown, the heat insulation member 16 fully expands and adheres tightly to both the inner tank 12 and the outer tank 14. Furthermore, in this state, the inner tank 12 is held in a state separated from the outer tank 14 by the heat insulation member 16.

[0058] It should be noted that, in this case, it is difficult to maintain a constant thickness of the insulation gap 18 during the stage prior to welding the outer can sheet 50. Therefore, in this case, a spacer 54 may also be locally disposed between the inner can 12 and the outer can sheet 50 (see reference). Figure 5A , Figure 5BThe structure of the spacer 54 is not particularly limited as long as it can maintain a constant thickness of the thermal insulation gap 18. Therefore, the spacer 54 can be made of resin or metal. Furthermore, the spacer 54 can be bonded to at least one of the inner tank 12 and the outer tank 14, or it can be unbonded. Additionally, to prevent concentrated loads from being transferred to a portion of the inner tank 12 via the spacer 54 during a vehicle collision, the spacer 54 can be a structure that is relatively easy to deform or break. For example, the spacer 54 may also have a bend or a weak point to induce bending.

[0059] Figure 6 This is a flowchart illustrating the manufacturing process of hydrogen tank 10. (For example...) Figure 6 As shown, in addition, as described above, when manufacturing the hydrogen tank 10, the operator evacuates the sealed bag 44 containing the heat insulation component 16 (S10). Next, the outer tank sheet 50 and the heat insulation component 16 are arranged around the inner tank 12 (S12). At this time, in order to keep the thickness of the heat insulation gap 18 as designed, a spacer 54 may also be arranged between the inner tank 12 and the outer tank sheet 50.

[0060] Next, the operator welds the outer can pieces 50 together to form a sealed outer can 14 (S14). Then, the operator connects the sealing valve 36 to a suction pump (not shown) to evacuate the insulation gap 18 (S16). This reduces the pressure difference between the inside and outside of the sealed bag 44, causing the insulation element 16 to expand. The expanded insulation element 16 then contacts both the outer can 14 and the inner can 12, keeping the inner can 12 separated from the outer can 14.

[0061] As is evident from the above description, in this example, a heat insulation member 16 is provided to keep the inner tank 12 separated from the outer tank 14. By providing this structure, even in the event of a strong impact on the hydrogen tank 10 due to a collision between the vehicle and an obstacle, damage to the inner tank 12 can be effectively prevented.

[0062] Furthermore, in this example, the internal pressure applied to the inner tank 12 can be distributed to the insulation 16 and the outer tank 14. Therefore, according to this example, the maximum allowable pressure of the hydrogen tank 10 can be increased without increasing the wall thickness of the inner tank 12 and the outer tank 14.

[0063] Furthermore, by providing the heat insulation element 16, the shape freedom of the inner tank 12 can be increased. Specifically, the inner tank 12 can be made into a shape with a flat portion. For example, as... Figure 7As shown, the inner tank 12 can also be made into a generally cubic shape with multiple flat portions 60. That is, in a configuration where the insulation gap 18 is not equipped with an insulation member 16, if the inner tank 12 is provided with flat portions 60, a large pressure will be exerted on these flat portions. In this case, the inner tank 12 may deform in the flat portion 60 and come into contact with the outer tank 14. Furthermore, if a part of the inner tank 12 comes into contact with the outer tank 14, the insulation performance will drop sharply, making it difficult to maintain liquid hydrogen at low temperatures. Therefore, conventional inner tanks 12 do not have flat portions 60 and are only composed of curved surfaces. That is, conventional inner tanks 12 are usually sandbag-shaped or spherical.

[0064] On the other hand, when the insulation member 16 is partially provided in the insulation gap 18 as in this example, even if the inner tank 12 has a flat portion 60, the pressure applied to the flat portion 60 can be borne by the insulation member 16 and the outer tank 14. As a result, deformation of the inner tank 12 can be effectively prevented. In addition, even if the inner tank 12 deforms, it can be effectively prevented from contacting the outer tank 14, and high insulation performance can be maintained. Therefore, according to this example, the degree of freedom in the shape of the inner tank 12 can be increased.

[0065] It should be noted that the structures described so far are all examples. Other structures can be modified as long as the space between the inner tank 12 and the outer tank 14 is partially filled with a heat insulation member 16. For example, in the above description, the heat insulation member 16 is housed in a sealed bag 44, but the heat insulation member 16 can also be directly disposed in the heat insulation gap 18 without being housed in the sealed bag 44. Furthermore, the shape of the hydrogen tank 10 can also be appropriately modified; for example, it can be spherical, rugby ball-shaped, cuboid, etc. Additionally, in this example, a booster pump 22 is provided in the hydrogen tank 10, but it is also possible to omit the booster pump 22.

[0066] Explanation of reference numerals in the attached figures

[0067] 10, 10* Hydrogen Tank, 12 Inner Tank, 14 Outer Tank, 16 Insulation Component, 18 Insulation Gap, 20 Collection Section, 22 Pump, 24 Pump Port, 25 Evaporation Port, 26 Liquid Hydrogen Filling Port, 28 Hydrogen Return Port, 29 Evaporation Valve, 30 Thermal Shielding Layer, 32 Spacer Layer, 34 Super Insulation Component, 36 Sealing Valve, 38 Rupture Disc, 40 Connecting Structural Component, 44 Sealing Bag, 50 Outer Tank Sheet, 54 Spacer Component, 60 Flat Section.

Claims

1. A method for manufacturing an onboard liquid hydrogen tank, characterized in that, The on-board liquid hydrogen tank has the following features: The inner tank stores liquid hydrogen. Outer container, housing the inner container; and A heat insulation component, disposed in the gap between the inner tank and the outer tank (i.e., the heat insulation gap), holds the inner tank in a state separated from the inner surface of the outer tank. The insulation gap has a vacuum area where the insulation is not filled and an area where the inner tank is supported by the surface of the insulation by filling the insulation. The thermal insulation component includes a super-insulating component formed by laminating one or more thermal shielding layers made of metal sheets and one or more spacer layers made of fiber materials. The thermal insulation gap is evacuated when the thermal insulation element is installed. The heat insulation component is housed in a sealed bag. The interior of the sealed bag and both sides of the heat insulation gap are evacuated. In the manufacturing method of the vehicle-mounted liquid hydrogen tank, After the thermal insulation component containing fibrous material is housed in a sealed bag, the inside of the sealed bag is evacuated. After placing the inner tank for storing the liquid hydrogen inside the outer tank and placing the sealed bag in the gap between the inner and outer tanks, i.e., the heat insulation gap, the heat insulation gap is evacuated. During the manufacturing of the vehicle-mounted liquid hydrogen tank, the sealed bag is positioned in the thermal insulation gap between the inner tank and the outer tank sheet. Before welding the outer tank sheet, the thermal insulation gap is not evacuated, and the thermal insulation component is pressed and compressed by atmospheric pressure. The thermal insulation component is thinner than the thermal insulation gap. Even with the thermal insulation component positioned in the thermal insulation gap, the inner tank or the outer tank sheet will not deform due to the pressing force from the thermal insulation component. The sealed bag is temporarily bonded to the inner tank or the outer tank sheet to prevent the sealed bag from moving within the thermal insulation gap. After the insulation is installed, the operator welds the outer can pieces together to form the outer can. After the outer can is formed, the operator evacuates the insulation gap, thereby reducing the pressure difference between the inside and outside of the sealed bag, eliminating the compression of the insulation, and allowing the insulation to fully expand and adhere tightly to both the inner and outer cans. The inner can is held in place by the insulation in a state separated from the outer can.

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