Safety device for high-pressure gas tank

Abstract

To operate a safety valve more appropriately in a safety device for a high-pressure gas tank.SOLUTION: A safety device 10 for a high-pressure gas tank 3 that internally accommodates a high-pressure gas as a fuel for a vehicle 2 comprises: a safety valve 1 that is attached to the high-pressure gas tank 3; and a heat pipe 5 that is attached to the safety valve 1. The safety valve 1 discharges the high-pressure gas from the inside of the high-pressure gas tank 3 to the outside as the temperature rises. The heat pipe 5 causes the heat to move by evaporation and condensation of a working liquid sealed therein and by the capillary action of wicks provided to an inner wall.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This invention relates to a safety device for a high-pressure gas tank that stores high-pressure gas as fuel for a vehicle inside it.

Background Art

[0002] Conventionally, there are vehicles that run on high-pressure gas as fuel. For example, fuel cell vehicles that run on electric power generated by a chemical reaction between hydrogen gas, which is a high-pressure gas, and oxygen (air) are known. Vehicles that use high-pressure gas as fuel are equipped with a high-pressure gas tank that stores the high-pressure gas inside.

[0003] Generally, a safety valve that releases high-pressure gas from inside the high-pressure gas tank to the outside as the temperature rises is attached to the high-pressure gas tank mounted on a vehicle. As such a safety valve, for example, Patent Document 1 discloses a thermally actuated overpressure prevention device that operates to release a part of the hydrogen (high-pressure gas) compressed and filled in a hydrogen tank (high-pressure gas tank) into the atmosphere in a short time when the internal temperature of the hydrogen tank reaches a predetermined temperature or higher.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since the above safety valve operates (opens) by heat, there is a risk that it may operate late or not at all when the temperature rises at a position far from the safety valve. Especially in commercial vehicles such as trucks and buses, since the high-pressure gas tank becomes larger, for example, even in the event of a fire near the high-pressure gas tank, the ignition position and the mounting position of the safety valve may be separated, and it may be difficult to properly operate the safety valve.

[0006] On the other hand, for example, by attaching safety valves at three or more locations including both ends and the middle of a high-pressure gas tank, it is conceivable to be able to respond to temperature rises at each of these locations. However, in this case, the manufacturing cost increases as the number of safety valves increases. Also, in a vehicle where a plurality of high-pressure gas tanks are provided separately from each other, even when there is a temperature rise near one high-pressure gas tank, in order to prevent secondary damage, it is desirable to operate the safety valve for the other high-pressure gas tanks as well and release the high-pressure gas to the outside.

[0007] The present invention was conceived in view of the above problems, and one of the objectives in the safety device for a high-pressure gas tank is to operate the safety valve more appropriately.

Means for Solving the Problems

[0008] The present invention was made to solve at least a part of the above problems and can be realized as the following aspects or application examples.

[0009] (1) The safety device for a high-pressure gas tank according to this aspect is a safety device for a high-pressure gas tank that stores high-pressure gas as fuel for a vehicle inside. It includes a safety valve that is attached to the high-pressure gas tank and releases the high-pressure gas from the inside of the high-pressure gas tank to the outside as the temperature rises, and a heat pipe that is connected to the safety valve and transfers heat by evaporation and condensation of the working fluid enclosed inside and the capillary phenomenon of a wick provided on the inner wall.

[0010] According to this aspect, since a heat pipe is connected to the safety valve that releases the high-pressure gas from the inside of the high-pressure gas tank to the outside as the temperature rises, heat can be transferred to the safety valve through a heat pipe that exhibits a high heat conductivity compared to stainless steel, copper, aluminum, etc. Thereby, for example, even when ignition occurs at a position far from the safety valve, heat moves quickly and efficiently from the ignition position to the safety valve through the heat pipe, so that the safety valve operates as the temperature rises and the high-pressure gas can be released appropriately. Therefore, according to this aspect, the safety valve can be operated more appropriately. That is, since the heat pipe with excellent thermal conductivity is extended, even without increasing the number of safety valves, the sensitivity to heat can be enhanced over a wide range and the temperature rise can be transmitted to the safety valve. Therefore, since the increase in the number of safety valves can be suppressed, the cost increase can be controlled. In addition, since the heat pipe is a heat transfer device for transmitting heat to the safety valve and high-pressure gas does not flow inside, even if it is deformed or damaged, leakage of high-pressure gas does not occur. Thus, for example, even if an impact is input during a vehicle collision, leakage of high-pressure gas can be suppressed.

[0011] (2) In the safety device of the high-pressure gas tank according to this aspect, the high-pressure gas tank may have a cylindrical intermediate portion and a pair of hemispherical end portions respectively formed on both sides of the intermediate portion, the safety valve may be attached to at least one of the end portions, and the heat pipe may include a main pipe extended along the intermediate portion from the safety valve attached to the end portion. According to such a configuration, even when the temperature rises in the intermediate portion of the high-pressure gas tank, heat can be transmitted to the safety valve through the main pipe. For this reason, for example, when a safety valve is attached to at least one of the end portions of the high-pressure gas tank, even if there is a temperature rise near the intermediate portion of the high-pressure gas tank, the safety valve can be operated appropriately. That is, even without additionally providing a safety valve in the intermediate portion of the high-pressure gas tank, according to the main pipe, when the temperature rises near the intermediate portion of the high-pressure gas tank, the safety valve attached to at least one of the end portions of the high-pressure gas tank can be operated. Therefore, while suppressing the cost increase, the high-pressure gas can be appropriately discharged from the high-pressure gas tank when the temperature rises.

[0012] (3) In the safety device of the high-pressure gas tank according to this aspect, the high-pressure gas tank may be mounted on the vehicle in a posture where the center of the intermediate portion extends in the horizontal direction, and the main pipe may extend downward from the safety valve attached to the end portion and then extend along the intermediate portion. According to such a configuration, the main pipe can be extended along the middle part of the high-pressure gas tank at a position lower than the safety valve. According to such a main pipe, the working fluid (gas) evaporated by the heat near the middle part of the high-pressure gas tank can transfer heat to the safety valve by moving upward due to the characteristics of the heat pipe. That is, since the heat transfer direction to the safety valve through the main pipe is upward, heat can be transferred to the safety valve more quickly and efficiently through the main pipe. Therefore, when the temperature rises near the middle part of the horizontally placed high-pressure gas tank where the center of the middle part extends in the horizontal direction, the safety valve can be operated more appropriately.

[0013] (4) In the safety device of the high-pressure gas tank according to this aspect, the high-pressure gas tank may be mounted on the vehicle in a posture where the center of the middle part extends in the vertical direction, the safety valve may be attached to the upper end part, and the main pipe may extend along the middle part after extending obliquely downward from the safety valve attached to the end part. According to such a configuration, the main pipe can be extended along the middle part of the high-pressure gas tank at a position lower than the safety valve. According to such a main pipe, since the heat transfer direction to the safety valve is upward as described above, heat can be transferred to the safety valve more quickly and efficiently through the main pipe. Therefore, when the temperature rises near the middle part of the vertically placed high-pressure gas tank where the center of the middle part extends in the vertical direction, the safety valve can be operated more appropriately.

[0014] (5) In the safety device of the high-pressure gas tank according to this aspect, the high-pressure gas tank may be installed outside the vehicle width direction of the chassis frame behind the cab of the vehicle, and the heat pipe may be provided in the space between the chassis frame and the high-pressure gas tank. According to such a configuration, for example, the heat pipe can be protected by the high-pressure gas tank against the impact input from the outside in the vehicle width direction during a side collision. Therefore, the risk of damage to the heat pipe during a side collision of the vehicle can be reduced.

[0015] (6) In the safety device for a high-pressure gas tank according to this aspect, the high-pressure gas tank may be installed between the cab and the rear body of the vehicle, and the heat pipe may be provided in the space between the rear body and the high-pressure gas tank. According to such a configuration, for example, the heat pipe can be protected by the high-pressure gas tank against the impact input from the front during a frontal collision. Therefore, the risk of damage to the heat pipe during a frontal collision of the vehicle can be reduced.

[0016] (7) The safety device for a high-pressure gas tank according to this aspect may include the safety valves respectively attached to a plurality of the high-pressure gas tanks, and the heat pipe may include a common pipe thermally connected to each of the safety valves. According to such a configuration, heat can be transferred to each of the safety valves attached to a plurality of high-pressure gas tanks through the common pipe. As a result, for example, even when ignition occurs at a position far from some of the safety valves, heat can move from the ignition position to each of the safety valves through the common pipe. As a result, by each safety valve operating as the temperature rises, the high-pressure gas can be appropriately discharged from the inside to the outside of each high-pressure gas tank. Therefore, in a vehicle equipped with a plurality of high-pressure gas tanks, when there is a temperature rise near one high-pressure gas tank, not only the safety valve attached to this high-pressure gas tank but also the safety valves attached to other high-pressure gas tanks can be appropriately operated. Thus, secondary damage can be effectively prevented.

[0017] (8) In the safety device for a high-pressure gas tank according to this aspect, the common pipe may extend along a gas supply pipe connected to a plurality of the high-pressure gas tanks to send the high-pressure gas to a predetermined supply destination. According to such a configuration, when the temperature rises near the gas supply pipe, heat can move to each of the plurality of safety valves through the common pipe. As a result, for example, when ignition occurs near the gas supply pipe, by each safety valve operating as the temperature rises, the high-pressure gas can be appropriately discharged from the inside to the outside of each high-pressure gas tank. Also, if the common pipe is laid along the existing gas supply pipe, the common pipe can be easily installed.

[0018] (9) In the safety device for a high-pressure gas tank according to this aspect, the common pipe may be extended along the vehicle height direction and thermally conductively connected to each of the safety valves respectively attached to the plurality of high-pressure gas tanks arranged in the vehicle height direction. According to such a configuration, the common pipe can be appropriately applied to the high-pressure gas tanks arranged in the vehicle height direction. Therefore, heat can be transferred to each safety valve through the common pipe at the time of temperature rise at any position in the vehicle height direction. Accordingly, each safety valve of the high-pressure gas tanks arranged in the vehicle height direction can be operated more appropriately.

[0019] (10) In the safety device for a high-pressure gas tank according to this aspect, the common pipe may be extended along the vehicle width direction and thermally conductively connected to each of the safety valves respectively attached to the plurality of high-pressure gas tanks arranged in the vehicle width direction. According to such a configuration, the common pipe can be appropriately applied to the high-pressure gas tanks arranged in the vehicle width direction. Therefore, heat can be transferred to each safety valve through the common pipe at the time of temperature rise at any position in the vehicle width direction. Accordingly, each safety valve of the high-pressure gas tanks arranged in the vehicle width direction can be operated more appropriately.

[0020] (11) In the safety device for a high-pressure gas tank according to this aspect, the safety valve may include a sensing part that opens a discharge port for discharging the high-pressure gas to the outside as the temperature rises, a housing that houses the sensing part, and a first connection part that is a hole or groove formed in a part adjacent to the sensing part in the housing. The heat pipe may be connected to the first connection part. According to such a configuration, heat is easily transferred from the heat pipe to the sensing part, so that the safety valve can be operated more appropriately. That is, by directly connecting the heat pipe to the housing of the safety valve, heat can be favorably transferred from the heat pipe to the sensing part in the housing via the housing. In addition, since the heat pipe can be connected only by forming holes or grooves in the existing housing, the manufacturing cost can be suppressed and the increase or decrease in the number of heat pipes can be flexibly coped with.

[0021] (12) In the safety device for a high-pressure gas tank according to this aspect, the safety valve may include a sensing part that opens a discharge port for discharging the high-pressure gas to the outside as the temperature rises, and a housing that houses the sensing part. The safety device may further include a collar having a second connection part that is formed of a material having a higher thermal conductivity than the housing and is attached to the housing and is a hole or groove formed at a position adjacent to the sensing part, and the heat pipe may be connected to the second connection part. According to such a configuration, heat is easily transferred from the heat pipe to the sensing part, so that the safety valve can be operated more appropriately. That is, by connecting the heat pipe to the housing via a collar having a higher thermal conductivity than the housing of the safety valve, heat can be favorably transferred from the heat pipe to the sensing part via the collar and the housing. In addition, since the heat pipe can be connected only by attaching a collar to the existing housing, the existing housing can be used as it is, and the increase or decrease in the number of heat pipes can be flexibly coped with by using the collar which is a retrofit part.

[0022] (13) The safety device for a high-pressure gas tank according to this aspect may further include a protection member formed in a plate shape or a lattice shape in which a large number of holes are formed and covering the heat pipe. According to such a configuration, while allowing heat from the surroundings to be transferred to the heat pipe, the heat pipe can be protected by the protection member. Therefore, for example, even when an impact is applied during a vehicle collision, deformation and damage of the heat pipe can be suppressed. Thus, the safety valve can be operated more appropriately.

[0023] (14) In the safety device for a high-pressure gas tank according to this aspect, the vehicle may be a fuel cell vehicle that drives a motor for running with the power of a fuel cell, and the high-pressure gas tank may be a hydrogen tank that stores hydrogen gas as the high-pressure gas inside. According to such a configuration, as described above, by the safety valve operating more appropriately, hydrogen gas can be appropriately released from the inside of the high-pressure gas tank to the outside. Therefore, it is possible to appropriately respond to a temperature rise in a fuel cell vehicle.

Effect of the Invention

[0024] According to the present case, in the safety device for a high-pressure gas tank, the safety valve can be operated more appropriately.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0026] With reference to the drawings, embodiments (aspects, application examples) of the present case will be described. The following embodiments are merely examples, and there is no intention to exclude various modifications and applications of technologies not explicitly shown in this embodiment. Each configuration of the following embodiments can be variously modified and implemented without departing from their gist. Also, they can be selectively adopted as necessary, or appropriately combined.

[0027] [1. Configuration] [1-1. Basic Configuration] As shown in FIG. 1, a safety device 10 for a high-pressure gas tank according to the present embodiment (hereinafter, also simply referred to as the safety device 10) is applied to a high-pressure gas tank 3 (hereinafter, also simply referred to as the tank 3) mounted on a vehicle 2. The vehicle 2 is, for example, a fuel cell vehicle that drives a motor 24 for running with the power of a fuel cell 23. Specifically, the vehicle 2 includes a high-voltage battery 25 that stores the power of the fuel cell 23, and drives the motor 24 with the power stored in the high-voltage battery 25.

[0028] Here, a vehicle 2 provided with a cab 21 where a driver's seat (not shown) is provided, a rear body 29 provided behind the cab 21, and a chassis frame 22 that supports the cab 21 and the rear body 29 from below is exemplified. In FIG. 1, both the cab 21 and the rear body 29 are shown by two-dot chain lines.

[0029] The chassis frame 22 of the present embodiment has a ladder frame structure. Specifically, the chassis frame 22 has a pair of side rails 26 extending in the vehicle length direction D1 (front-rear direction) and a plurality of cross members 27 (only two are shown in FIG. 1) extending in the vehicle width direction D2 (left-right direction), forming a ladder shape. The pair of side rails 26 are spaced apart from each other in the vehicle width direction D2, and each cross member 27 connects the pair of side rails 26. The rear body 29 is, for example, a cargo box. Thus, the vehicle 2 may be a truck (fuel cell truck) equipped with the rear body 29 which is a cargo box.

[0030] The fuel cell 23 is a device that generates electricity through a chemical reaction between hydrogen and oxygen (air). The fuel cell 23 is disposed, for example, between the pair of side rails 26 below the cab 21. Hydrogen gas is supplied to the fuel cell 23 through a gas supply pipe 28 and a downstream pipe 31, which will be described later, from the tank 3. That is, the fuel cell 23 is a predetermined supply destination to which hydrogen gas is supplied from the tank 3.

[0031] The high-voltage battery 25 is disposed, for example, between the pair of side rails 26 behind the cab 21 and the fuel cell 23. Also, the motor 24 is disposed, for example, between the pair of side rails 26 behind the high-voltage battery 25. The motor 24 is modularized with an inverter (not shown).

[0032] The tank 3 is a sealed container that houses high-pressure gas as fuel for the vehicle 2. The tank 3 mounted on the vehicle 2 which is a fuel cell vehicle is a hydrogen tank that houses hydrogen gas as high-pressure gas. In the present embodiment, two (a plurality of) tanks 3 (first tank 3A and second tank 3B) installed outside the chassis frame 22 in the vehicle width direction D2 behind the cab 21 are exemplified.

[0033] The first tank 3A is provided outside the side rail 26 on one side (the left side in FIG. 1) in the vehicle width direction D2 among a pair of side rails 26 extending in the vehicle length direction D1 in the chassis frame 22 having a ladder frame structure. Further, the second tank 3B is provided outside the side rail 26 on the other side (the right side in FIG. 1) in the vehicle width direction D2. Thus, in the present embodiment, the first tank 3A is disposed on the left side of the left side rail 26, and the second tank 3B is disposed on the right side of the right side rail 26.

[0034] Each tank 3 has, for example, a cylindrical intermediate portion 3c and a pair of hemispherical end portions 3f and 3r formed on both sides of the intermediate portion 3c, respectively. In the present embodiment, the tank 3 which is a horizontally-mounted tank installed in a posture where the center 3d (axis, hereinafter also referred to as the tank center 3d) of the intermediate portion 3c extends in the horizontal direction is exemplified. More specifically, the tank 3 is installed in a posture where the tank center 3d extends along the vehicle length direction D1 similarly to the side rail 26. Regarding the tank 3 arranged in such a posture, when distinguishing between a pair of end portions 3f and 3r located on both sides of the tank center 3d from each other, one on the front side is also referred to as the front end portion 3f, and the other on the rear side is also referred to as the rear end portion 3r.

[0035] In the present embodiment, the first tank 3A and the second tank 3B having the same shape as each other and installed in the same posture as each other are exemplified. However, the shape and posture of each tank 3 are not limited to the above example, and the first tank 3A and the second tank 3B may have different shapes from each other or may be mounted on the vehicle 2 in different postures.

[0036] Each tank 3 is disposed in the space between the front wheels 34 and the rear wheels 35 of the vehicle 2. Further, from the viewpoint of safety, the tank 3 is disposed inward by a predetermined dimension or more from the outer surface 37 of the vehicle 2 (for example, the outermost surface of the rear body 29) in the vehicle width direction D2. Therefore, a space of a predetermined dimension or more is provided outside the tank 3 in the vehicle width direction D2.

[0037] Two tanks 3 are connected to a gas supply pipe 28 for sending high-pressure gas to a predetermined supply destination. The gas supply pipe 28 of the present embodiment is a pipe for sending hydrogen gas from each tank 3 to the fuel cell 23, extends along the vehicle width direction D2, and connects the front end portions 3f of the two tanks 3 to each other. The gas supply pipe 28 is connected to the fuel cell 23 via a downstream pipe 31. Various devices (not shown) such as a filter and a valve are provided on the downstream pipe 31.

[0038] A fan 9 and a heat exchanger 4 are installed outside the two tanks 3 in the vehicle width direction D2. The fan 9 and the heat exchanger 4 are arranged in a space having a predetermined dimension or more provided outside the two tanks 3 in the vehicle width direction D2 as described above. In other words, the fan 9 and the heat exchanger 4 are mounted using the dead space existing outside the two tanks 3 in the vehicle width direction D2.

[0039] The heat exchanger 4 is a device that performs heat exchange between a refrigerant for cooling devices mounted on the vehicle 2 and air. The fan 9 is a blower device (so-called radiator fan) that induces air to the heat exchanger 4. FIG. 1 shows an example in which the heat exchanger 4 is arranged outside the fan 9 in the vehicle width direction D2. However, the arrangement of the fan 9 and the heat exchanger 4 is not limited to this. The fan 9 may be provided so as to be able to induce air to the heat exchanger 4. For example, contrary to the example of FIG. 1, the fan 9 may be arranged outside the heat exchanger 4 in the vehicle width direction D2. In addition, FIG. 1 shows an example in which a plurality of fans 9 are arranged along the vehicle length direction D1, but the number and arrangement of the fans 9 are not limited to this.

[0040] A side cover 32 is attached outside the fan 9 and the heat exchanger 4 in the vehicle width direction D2 to protect the fan 9 and the heat exchanger 4. The side cover 32 is provided with slits (not shown) for efficiently taking in the traveling wind into the fan 9 and the heat exchanger 4 (inside in the vehicle width direction D2).

[0041] [1-2. Main component configuration] The safety device 10 according to this embodiment includes a safety valve 1 attached to the tank 3 and a heat pipe 5 connected to the safety valve 1. Here, an example is shown in which the safety valve 1 is attached to each end 3f, 3r of the tank 3 on the tank center 3d. In this way, for a relatively large tank 3, it is preferable that a plurality of safety valves 1 are attached to a plurality of locations (each end 3f, 3r in this embodiment) on the tank 3. However, at least one safety valve 1 may be attached to each tank 3, and for example, it may be attached only to one of the ends 3f, 3r (the front end 3f or the rear end 3r) of each tank 3.

[0042] The safety valve 1 is a device that discharges high-pressure gas from the inside of the tank 3 to the outside as the temperature rises, and is also called a TPRD (Thermal Pressure Relief Device). The safety valve 1 attached to the front end 3f of each tank 3 is provided as an OTV (On Tank Valve) having various functions such as a temperature sensor, a pressure sensor, and a solenoid valve (not shown). On the other hand, the safety valve 1 attached to the rear end 3r of each tank 3 is provided as a plug having only the function as a TPRD.

[0043] As shown in FIG. 2, the safety valve 1 of this embodiment has a glass cylinder 12 (sensing part) filled with liquid and a housing 6 that houses the cylinder 12. The housing 6 has a main body part 13 that forms a passage for high-pressure gas and a bottomed cylindrical cap 14 that covers the cylinder 12 and is attached to the main body part 13, and is formed of, for example, stainless steel. In FIG. 2, the cross-sectional view (hatching) of the cylinder 12 is omitted.

[0044] In the main body portion 13 of the housing 6, an inlet port 6a communicating with the tank 3, an outlet port 6b for discharging high-pressure gas toward a predetermined supply destination, and a gas passage 6c extending between the inlet port 6a and the outlet port 6b are formed. Further, in the main body portion 13, a discharge port 6d for discharging high-pressure gas from the inside of the tank 3 to the outside of the vehicle 2 and a discharge passage 6e branching from the gas passage 6c and extending to the discharge port 6d are further formed. The gas supply pipe 28 shown in FIG. 1 is connected to the outlet port 6b of the present embodiment. Further, a discharge pipe (not shown) for discharging high-pressure gas to the outside of the vehicle 2 is connected to the discharge port 6d.

[0045] In the housing 6, a plunger 11 that can reciprocate in the discharge passage 6e is provided. The plunger 11 is disposed in the discharge passage 6e in a state of being biased toward the cylinder 12 and the cap 14 by a spring 18 provided on its outer periphery. In the state where the plunger 11 is biased with respect to the cap 14 via the cylinder 12 in this way, it is fixed at a position where the discharge passage 6e is closed. Therefore, in this state, the discharge port 6d is closed. It can be said that the state where the discharge port 6d is closed is a state where the safety valve 1 is not operating (closed).

[0046] On the other hand, when the liquid in the cylinder 12 expands due to a temperature rise and the cylinder 12 cracks, the plunger 11 moves toward the cap 14 side by the biasing force of the spring 18. As a result, the plunger 11 moves to a position where the discharge passage 6e is opened. Thereby, since the discharge port 6d is opened, high-pressure gas is discharged from the inside of the tank 3 to the outside through the discharge passage 6e and the discharge port 6d.

[0047] In this way, the cylinder 12 has the function of moving the plunger 11 due to deformation accompanying temperature rise, thereby opening the discharge passage 6e in the plunger 11. That is, the cylinder 12 opens the discharge port 6d as the temperature rises. It can be said that the state in which the discharge port 6d is open is the state in which the safety valve 1 operates (opens). Note that the cylinder 12 and the cap 14 that houses it are provided so as to protrude from the main body 13 so that the liquid in the cylinder 12 can receive the surrounding heat well (the sensitivity to the surrounding temperature rise increases).

[0048] As shown in FIGS. 1 and 3, the heat pipe 5 is a tubular heat transfer device. The heat pipe 5 transfers heat by the evaporation and condensation of the working fluid sealed inside and the capillary action of the wick provided on the inner wall. Specifically, the heat pipe 5 has a liquid (such as pure water or alcohol) called a working fluid sealed in a cavity of a pipe formed of a material (such as copper or aluminum) with a relatively high thermal conductivity, and a capillary structure called a wick is formed on the inner wall of this pipe.

[0049] In the heat pipe 5, when a high-temperature part, which is a part of it, receives heat, the working fluid in the high-temperature part evaporates into a gas, moves through the cavity of the pipe, and moves to a low-temperature part, which is another part. Then, the working fluid that has moved to the low-temperature part condenses back into a liquid, is absorbed by the inner wall of the pipe due to the capillary action of the wick, and returns to the high-temperature part. The heat pipe 5 can transfer heat quickly by transporting the heat of the high-temperature part to the low-temperature part in this way.

[0050] When heat is transferred in the heat pipe 5, the gas moving from the high-temperature part to the low-temperature part tends to move upward, which is opposite to the direction of the action of gravity, and the liquid returning from the low-temperature part to the high-temperature part tends to move downward, which is the direction of the action of gravity. Therefore, it can be said that the heat pipe 5 exhibits a particularly good function (higher thermal conductivity) during upward heat transfer.

[0051] Generally, the thermal conductivity is about 15 [W / m·K] for stainless steel, about 200 [W / m·K] for aluminum, and about 400 [W / m·K] for copper, while for the heat pipe 5, it can reach about 4000 to 100000 [W / m·K]. Thus, the heat pipe 5 has a very high thermal conductivity compared to stainless steel, aluminum, and copper.

[0052] As shown in FIG. 1, the heat pipe 5 of this embodiment includes a main pipe 51 extending along each tank 3 and a common pipe 52 thermally connected to each of the safety valves 1 of the two tanks 3. The common pipe 52 of this embodiment extends along the gas supply pipe 28. That is, the common pipe 52 is laid along the vehicle width direction D2 so as to connect the safety valves 1 attached to the front end portions 3f of the two tanks 3 to each other.

[0053] On the other hand, the main pipe 51 extends along the intermediate portion 3c from the safety valves 1 attached to the end portions 3f, 3r in each tank 3. More specifically, the main pipe 51 forms a shape that curves in an arc along the hemispherical end portions 3f, 3r from the safety valves 1 and then extends straight parallel to the tank center 3d along the cylindrical intermediate portion 3c. The main pipe 51 is provided close to the outer surface of the tank 3 so as not to protrude from the tank 3.

[0054] As shown in FIG. 3, the main pipe 51 of this embodiment is provided in the space between the chassis frame 22 and the tank 3. More specifically, the main pipe 51 is provided outside the side rail 26 in the vehicle width direction D2 and inside the tank center 3d in the vehicle width direction D2 at the same height position as the side rail 26. Here, the main pipe 51 provided above (at a higher position) than the tank center 3d is illustrated.

[0055] The main pipe 51 is fixed to, for example, a mount 38 or a stay 39 that fixes the tank 3 to the chassis frame 22 via a clamp or a bracket (not shown). However, the structure for fixing the main pipe 51 is not limited to this. The main pipe 51 of the present embodiment is provided in the space between the mount 38 fixed to the side rail 26 and the tank 3.

[0056] As shown by the dashed-dotted line in FIG. 3, the main pipe 51 may be provided in the space between the fan 9 (or the heat exchanger 4) and the tank 3 instead of or in addition to the above position. Specifically, the main pipe 51 may be laid along the tank 3 outside the vehicle width direction D2 from the tank center 3d. The main pipe 51 shown by the dashed-dotted line in FIG. 3 is provided below (at a lower position) than the tank center 3d. Such a main pipe 51 extends downward from the safety valve 1 attached to the end portions 3f and 3r in each tank 3 and then extends along the intermediate portion 3c.

[0057] As shown by the dashed-dotted line in FIG. 3, the safety device 10 may further include a protection member 8 that covers the main pipe 51 (heat pipe 5). The protection member 8 is formed in a plate shape or a lattice shape with a large number of holes so that the heat pipe 5 is not less likely to receive ambient heat. The protection member 8 has a function of protecting the heat pipe 5 from a collision load, for example, when the vehicle 2 collides, by covering at least a part of the heat pipe 5. For the main pipe 51 provided outside the vehicle width direction D2 from the tank center 3d as described above, the protection member 8 may be provided so as to cover the main pipe 51 from the outside in the vehicle width direction D2 in order to ensure the protection performance against the load from the outside in the vehicle width direction D2.

[0058] As shown in FIG. 4, as a connection structure between the safety valve 1 and the heat pipe 5, the safety valve 1 may further have a housing hole 15 (first connection portion) formed in the housing 6. The housing hole 15 shown in FIG. 4 is a hole formed in a portion of the housing 6 adjacent to the cylinder 12. Here, an example of the housing hole 15 formed in a portion near the cap 14 in the main body portion 13 of the housing 6 is illustrated. Note that the safety valve 1 shown in FIGS. 4 and 5 to 7 described later has a different shape of the main body portion 13 from that shown in FIG. 2, but the essential functional elements (such as the plunger 11 and the cylinder 12) are similarly configured.

[0059] The heat pipe 5 is connected to the housing hole 15. Specifically, the heat pipe 5 is fixed in a state of being in contact with the wall surface forming the housing hole 15 in the main body portion 13. Thereby, the heat received by the heat pipe 5 is transmitted to the cylinder 12 via the housing 6. In order to enhance such heat conductivity from the heat pipe 5 to the cylinder 12, it is preferable that the housing hole 15 is formed at a position as close as possible to the cylinder 12, and a large contact area between the heat pipe 5 and the housing 6 is ensured.

[0060] Instead of or in addition to the connection structure shown in FIG. 4, as shown in FIG. 5, the safety device 10 may include a collar 7 attached to the housing 6. The collar 7 is formed of a material having a higher thermal conductivity than the housing 6. For example, when the housing 6 is formed of stainless steel, the collar 7 may be formed of copper or aluminum. FIG. 5 illustrates a collar 7 attached to the cap 14 of the housing 6.

[0061] The collar 7 has an annular attachment portion 7a that is externally fitted to the cap 14 of the housing 6, an arm portion 7b that extends radially outward from the attachment portion 7a, and a collar hole 16 (second connection portion) formed in the arm portion 7b. The collar hole 16 shown in FIG. 5 is a hole formed in a portion of the collar 7 adjacent to the cylinder 12. Here, an example in which one collar hole 16 is formed in the substantially trapezoidal arm portion 7b provided in the collar 7 is shown.

[0062] The heat pipe 5 is connected to the color hole 16. Specifically, the heat pipe 5 is fixed in contact with the wall surface forming the color hole 16 at the color 7. Thereby, the heat received by the heat pipe 5 is transmitted to the cylinder 12 via the color 7 and the housing 6. In order to enhance the heat conductivity from such a heat pipe 5 to the cylinder 12, the color hole 16 is preferably formed at a position as close as possible to the cylinder 12, and it is preferable that both the contact area between the heat pipe 5 and the color 7 and the contact area between the color 7 and the housing 6 are ensured to be large. Note that the housing hole 15 and the color hole 16 are not limited to the holes as described above, and various shapes capable of connecting the heat pipe 5 can be adopted. For example, it may be a groove into which the heat pipe 5 can be fitted.

[0063] When a plurality of heat pipes 5 are connected to one safety valve 1, for example, as shown in FIG. 6, the arm portion 7b of the color 7 may be enlarged, and a plurality of color holes 16 may be formed in the arm portion 7b. Thus, if the color 7 has a plurality of color holes 16, a plurality of main pipes 51 or a combination of the main pipe 51 and the common pipe 52 can be connected to one safety valve 1. Instead of or in addition to this, a plurality of housing holes 15 may be formed in the housing 6 so that a plurality of heat pipes 5 can be connected to one safety valve 1.

[0064] Note that when the heat conductivity of the housing 6 is low, a connection material (interface) for transmitting heat may be provided between the housing hole 15 and the cylinder 12 or between the color 7 and the cylinder 12. Such a connection material is formed of a material having a higher heat conductivity than the housing 6, similar to the color 7.

[0065] Alternatively, as shown in FIG. 7, a plurality of heat pipes 5 may be coupled to each other by a coupling block 17 having thermal conductivity. The coupling block 17 is formed of a material having a relatively high thermal conductivity (such as copper or aluminum). FIG. 7 shows an example in which the main pipe 51 and the common pipe 52 are coupled to each other by a coupling block 17 near the boundary between the front end portion 3f and the middle portion 3c of the tank 3. In this case, the common pipe 52 is connected to the safety valve 1 so as to be thermally conductive through a part of the main pipe 51 and the coupling block 17. Thus, the common pipe 52 may be connected to the safety valve 1 so as to be at least thermally conductive, and may not be directly connected to the safety valve 1.

[0066] [1-3. Modification Example] The mounting posture and mounting position of the tank 3 in the vehicle 2 are not limited to the above example. For example, as shown as modification examples in FIGS. 8 to 11, the tank 3 may be installed between the cab 21 and the rear body 29 of the vehicle 2. In FIGS. 8 to 11, elements that are the same as or corresponding to the elements already described are denoted by the same reference numerals, and redundant descriptions are omitted below.

[0067] Each vehicle 2 of the modification examples includes a tank box 30 disposed along the back surface of the cab 21. A plurality of tanks 3 are accommodated inside the tank box 30. In the first modification example shown in FIG. 8, a horizontally disposed tank 3 in which the tank center 3d (only one is denoted by a reference numeral in FIG. 8) extends in the horizontal direction is illustrated. More specifically, each tank 3 of the first modification example is mounted on the vehicle 2 in a posture in which the tank center 3d extends along the vehicle width direction D2. The plurality of tanks 3 are arranged in the vehicle height direction D3 inside the tank box 30.

[0068] The heat pipe 5 of each modification example is provided in the space between the rear body 29 and the tank 3. As shown in FIG. 9, the main pipe 51 of the first modification example extends downward and rearward from the safety valves 1 attached to the end portions 3f and 3r in each tank 3, and then extends along the intermediate portion 3c. In this way, the main pipe 51 is provided below (at a lower position) and rearward (on the rear body 29 side) of the tank center 3d. In FIGS. 9 to 11, the tank box 30 is shown in a perspective state (two-dot chain line), the rear body 29 and other structures unnecessary for the description are omitted, and reference numerals are attached only to a part of the plurality of configurations.

[0069] As shown in FIG. 9, the common pipe 52 of the first modification example extends along the vehicle height direction D3 corresponding to a plurality of tanks 3 arranged in the vehicle height direction D3. The common pipe 52 is connected to each of the main pipes 51 via a coupling block 17. Thereby, the common pipe 52 is thermally conductively connected to each of the plurality of safety valves 1 attached to the plurality of tanks 3 arranged in the vehicle height direction D3 via the coupling block 17 and the main pipe 51. The common pipe 52 of this modification example is preferably extended from a height position below the lower end portion of the lowermost tank 3 to a height position above the upper end portion of the uppermost tank 3 so as to cover the entire area of the plurality of tanks 3 in the vehicle height direction D3.

[0070] FIG. 9 illustrates one common pipe 52 provided at approximately the center in the vehicle width direction D2 of each tank 3 and rearward (on the rear body 29 side) of the tank center 3d. However, the position and number of the common pipes 52 are not limited to this. For example, the common pipe 52 may be provided at a position biased to either the left or right side of each tank 3, or a plurality of common pipes 52 may be arranged at intervals in the vehicle width direction D2.

[0071] Also, as shown in FIG. 10 as a second modification example, the common pipe 52 may be directly connected to the safety valve 1 attached to each tank 3. Here, an example of one common pipe 52 directly connected to the safety valve 1 attached to one end portion 3r (the right end portion 3r in FIG. 10) of each tank 3 is illustrated. Instead of or in addition to this, a common pipe 52 directly connected to the safety valve 1 attached to the other end portion 3f (the left end portion 3f in FIG. 10) of each tank 3 may be provided. Note that the position of such a common pipe 52 can be appropriately changed according to the position of the safety valve 1.

[0072] When the common pipe 52 is directly connected to the safety valve 1 as in this modification example, part or all of the main pipe 51 may be omitted. For example, as shown in FIG. 10, the main pipe 51 may be provided only for the tank 3 located at the lowest position. In addition to this, for example, as shown by the two-dot chain line in FIG. 10, the main pipe 51 may be provided for the tank 3 located at the highest position.

[0073] As shown in FIG. 11 as a third modification example, the tank 3 mounted on the vehicle 2 may be a vertically mounted tank installed in a posture where the tank center 3d extends in the vertical direction (vehicle height direction D3). For the tank 3 arranged in such a posture, when distinguishing between the pair of end portions 3f and 3r from each other, the upper one is also referred to as the upper end portion 3f, and the lower one is also referred to as the lower end portion 3r. FIG. 11 shows an example in which a plurality of vertically mounted tanks 3 are arranged in the vehicle width direction D2 inside the tank box 30.

[0074] In this modification example, the safety valve 1 is attached only to the upper end portion 3f of each tank 3. And the main pipe 51 extends obliquely downward (rearward and downward in this modification example) from the safety valve 1 attached to the upper end portion 3f in each tank 3 and then extends along the intermediate portion 3c. The main pipe 51 extends to the vicinity of the lower end portion 3r where the safety valve 1 is not attached in the tank 3. Here, an example of the main pipe 51 provided rearward (on the rear body 29 side) of the tank center 3d is illustrated.

[0075] In addition, the common pipe 52 of the third modification example extends along the vehicle width direction D2 corresponding to a plurality of tanks 3 arranged in the vehicle width direction D2, and is connected to each of the main pipes 51 via a coupling block 17. Thereby, the common pipe 52 is thermally conductively connected to each of the plurality of safety valves 1 respectively attached to the plurality of tanks 3 arranged in the vehicle width direction D2 via the main pipe 51.

[0076] FIG. 11 illustrates one common pipe 52 provided slightly above (at a higher position) than the lower end portion 3r of the tank 3. However, the common pipe 52 may be provided, for example, substantially at the center in the vehicle height direction D3 of the main pipe 51, or a plurality of common pipes 52 may be arranged at intervals in the vehicle height direction D3. In this modification example as well, it is preferable that the common pipe 52 extends over a length equal to or greater than the distance between the left and right end portions of the plurality of tanks 3 so as to cover the entire area of the plurality of tanks 3 in the vehicle width direction D2.

[0077] [2. Operations and Effects] (1) According to the above-described safety device 10, since the heat pipe 5 is connected to the safety valve 1 that discharges the high-pressure gas from the inside of the tank 3 to the outside as the temperature rises, heat can be transmitted to the safety valve 1 through the heat pipe 5 that exhibits a higher thermal conductivity compared to stainless steel, copper, aluminum, etc. Thereby, for example, even when ignition occurs at a position far from the safety valve 1, heat moves quickly and efficiently from the ignition position to the safety valve 1 through the heat pipe 5, so that the safety valve 1 operates as the temperature rises and the high-pressure gas can be appropriately discharged.

[0078] Therefore, according to the safety device 10, the safety valve 1 can be operated more appropriately. That is, since the heat pipe 5 with excellent thermal conductivity is extended, even without increasing the number of safety valves 1, the sensitivity to heat can be enhanced over a wide range and the temperature rise can be transmitted to the safety valve 1. Therefore, since an increase in the number of safety valves 1 can be suppressed, an increase in cost can be suppressed. Further, since the heat pipe 5 is a heat transfer device for transferring heat to the safety valve 1 and high-pressure gas does not flow inside, even if it is deformed or damaged, leakage of high-pressure gas does not occur. Thus, for example, even when an impact is input during a collision of the vehicle 2, leakage of high-pressure gas can be suppressed.

[0079] (2) According to the main pipe 51 that extends along the cylindrical intermediate portion 3c from the safety valve 1 attached to at least one of the hemispherical end portions 3f and 3r of the tank 3, heat can be transmitted to the safety valve 1 through the main pipe 51 even when the temperature rises in the intermediate portion 3c of the tank 3. For this reason, for example, when the safety valve 1 is attached to at least one of the end portions 3f and 3r of the tank 3, even if there is a temperature rise near the intermediate portion 3c of the tank 3, the safety valve 1 can be operated appropriately. That is, even without additionally providing the safety valve 1 in the intermediate portion 3c of the tank 3, according to the main pipe 51, when the temperature rises near the intermediate portion 3c of the tank 3, the safety valve 1 attached to at least one of the end portions 3f and 3r of the tank 3 can be operated. Therefore, while suppressing an increase in cost, high-pressure gas can be appropriately discharged from the tank 3 when the temperature rises.

[0080] (3) For example, as shown in FIGS. 9 and 10, if the main pipe 51 extends downward from the safety valve 1 attached to the end portions 3f and 3r in the horizontally placed tank 3 and then extends along the middle portion 3c, the main pipe 51 can be extended along the middle portion 3c of the tank 3 at a position lower than the safety valve 1. According to such a main pipe 51, the working fluid (gas) evaporated by the heat near the middle portion 3c of the tank 3 can transfer heat to the safety valve 1 by moving upward due to the characteristics of the heat pipe 5. That is, since the heat transfer direction to the safety valve 1 through the main pipe 51 is upward, heat can be transferred to the safety valve 1 more quickly and efficiently through the main pipe 51. Therefore, when the temperature rises near the middle portion 3c in the horizontally placed tank 3, the safety valve 1 can be operated more appropriately.

[0081] (4) As shown in FIG. 11, if the main pipe 51 extends obliquely downward from the safety valve 1 attached to the upper end portion 3f in the vertically placed tank 3 and then extends along the middle portion 3c, the main pipe 51 can be extended along the middle portion 3c of the tank 3 at a position lower than the safety valve 1. According to such a main pipe 51, as described above, since the heat transfer direction to the safety valve 1 is upward, heat can be transferred to the safety valve 1 more quickly and efficiently through the main pipe 51. Therefore, when the temperature rises near the middle portion 3c in the vertically placed tank 3, the safety valve 1 can be operated more appropriately.

[0082] Further, if the main pipe 51 extends to the vicinity of the lower end portion 3r of the vertically placed tank 3, even if the safety valve 1 is not provided at the lower end portion 3r, heat can be transferred to the safety valve 1 attached to the upper end portion 3f through the main pipe 51 when the temperature rises near the lower end portion 3r. Thereby, since the number of safety valves 1 can be suppressed, an increase in cost can be further suppressed.

[0083] (5) As shown in FIG. 3, if the heat pipe 5 is provided in the space between the chassis frame 22 and the tank 3 installed outside in the vehicle width direction D2 with respect to this, for example, against the impact input from the outside in the vehicle width direction D2 during a side collision, the heat pipe 5 can be protected by the tank 3. For this reason, the risk of damage to the heat pipe 5 during a side collision of the vehicle 2 can be reduced.

[0084] (6) As shown in FIGS. 8 to 11, if the heat pipe 5 is provided in the space between the rear body 29 and the tank 3 installed between the cab 21 and the rear body 29, for example, against the impact input from the front during a frontal collision, the heat pipe 5 can be protected by the tank 3. Therefore, the risk of damage to the heat pipe 5 during a frontal collision of the vehicle 2 can be reduced.

[0085] (7) According to the common pipe 52 thermally connected to each of the safety valves 1 attached to the plurality of tanks 3, heat can be transferred to each of the safety valves 1 attached to the plurality of tanks 3 through the common pipe 52. Thus, for example, even when ignition occurs at a position far from some of the safety valves 1, heat can move from the ignition position to each of the safety valves 1 through the common pipe 52. As a result, as each safety valve 1 operates with an increase in temperature, the high-pressure gas can be appropriately discharged from the inside to the outside of each tank 3. Therefore, in the vehicle 2 equipped with the plurality of tanks 3, when there is a temperature rise near one tank 3, not only the safety valve 1 attached to this tank 3 but also the safety valves 1 attached to the other tanks 3 can be appropriately operated. Thus, secondary damage can be effectively prevented.

[0086] As shown in FIG. 9, if the common pipe 52 is connected to the safety valve 1 via the main pipe 51, heat can be transferred from the common pipe 52 to the safety valve 1 through the main pipe 51, and it is not necessary to directly connect the common pipe 52 to the safety valve 1, so the degree of freedom in arranging the common pipe 52 can be increased. On the other hand, as shown in FIG. 10, if the common pipe 52 is directly connected to the safety valve 1, heat can be transferred from the common pipe 52 to the safety valve 1 faster and more reliably, so the safety valve 1 can be operated more appropriately.

[0087] (8) As shown in Fig. 1, if the common pipe 52 extends along the gas supply pipe 28 for sending high-pressure gas to a predetermined supply destination, heat can be transferred through the common pipe 52 to each of the plurality of safety valves 1 when the temperature rises in the vicinity of the gas supply pipe 28. As a result, for example, when ignition occurs in the vicinity of the gas supply pipe 28, each safety valve 1 operates as the temperature rises, so that the high-pressure gas can be appropriately discharged from the inside to the outside of each tank 3. Also, if the common pipe 52 is laid along the existing gas supply pipe 28, the common pipe 52 can be easily installed.

[0088] (9) As shown in Figs. 9 and 10, if the common pipe 52 extending along the vehicle height direction D3 is thermally conductively connected to each of the safety valves 1 attached to the plurality of tanks 3 arranged in the vehicle height direction D3, the common pipe 52 can be appropriately applied to the tanks 3 arranged in the vehicle height direction D3. For this reason, heat can be transferred to each safety valve 1 through the common pipe 52 when the temperature rises at any position in the vehicle height direction D3. Therefore, each safety valve 1 of the tanks 3 arranged in the vehicle height direction D3 can be operated more appropriately.

[0089] (10) As shown in Fig. 11, if the common pipe 52 extending along the vehicle width direction D2 is thermally conductively connected to each of the safety valves 1 attached to the plurality of tanks 3 arranged in the vehicle width direction D2, the common pipe 52 can be appropriately applied to the tanks 3 arranged in the vehicle width direction D2. For this reason, heat can be transferred to each safety valve 1 through the common pipe 52 when the temperature rises at any position in the vehicle width direction D2. Therefore, each safety valve 1 of the tanks 3 arranged in the vehicle width direction D2 can be operated more appropriately.

[0090] (11) As shown in Fig. 4, if the heat pipe 5 is connected to the housing hole 15 adjacent to the cylinder 12 that opens the discharge port 6d as the temperature rises in the safety valve 1, from the heat pipe 5 to the cylinder 12 Since heat is more easily transferred, the safety valve 1 can be operated more appropriately. That is, by directly connecting the heat pipe 5 to the housing 6 of the safety valve 1, heat can be well transferred from the heat pipe 5 through the housing 6 to the cylinder 12. In addition, since the heat pipe 5 can be connected only by forming holes or grooves in the existing housing 6, the manufacturing cost can be suppressed and the increase or decrease in the number of heat pipes 5 can be flexibly accommodated.

[0091] (12) As shown in FIGS. 5 and 6, if the heat pipe 5 is connected to a collar hole 16 adjacent to the cylinder 12 in a collar 7 attached to the housing 6 of the safety valve 1, heat is more easily transferred from the heat pipe 5 to the cylinder 12, so that the safety valve 1 can be operated more appropriately. That is, by connecting the heat pipe 5 to the housing 6 through a collar 7 having a higher thermal conductivity than the housing 6 of the safety valve 1, heat can be well transferred from the heat pipe 5 through the collar 7 and the housing 6 to the cylinder 12. In addition, since the heat pipe 5 can be connected only by attaching the collar 7 to the existing housing 6, the existing housing 6 can be used as it is, and the increase or decrease in the number of heat pipes 5 can be flexibly accommodated by using the collar 7 which is a retrofit part.

[0092] (13) As shown in FIG. 3, if a protective member 8 formed in a plate shape or a lattice shape with a large number of holes covers the heat pipe 5, heat from the surroundings can be transferred to the heat pipe 5 while the heat pipe 5 can be protected by the protective member 8. Therefore, for example, even when an impact is applied during a collision of the vehicle 2, deformation and damage of the heat pipe 5 can be suppressed. Thus, the safety valve 1 can be operated more appropriately.

[0093] (14) If the safety device 10 is applied to a tank 3 which is a hydrogen tank mounted on a vehicle 2 which is a fuel cell vehicle, the safety valve 1 operates more appropriately as described above, so that hydrogen gas can be appropriately released from the inside of the tank 3 to the outside. Therefore, it is possible to appropriately respond to a temperature rise in the fuel cell vehicle.

[0094] [3. Others] The configurations of the above-described embodiments and modifications can be combined as appropriate. For example, in the modifications shown in FIGS. 8 to 11, the common pipe 52 may extend along a gas supply pipe (not shown) connected to the plurality of tanks 3. Further, in the modifications shown in FIGS. 8 to 11, the collar 7 of FIGS. 5 to 6 may be applied to the connection structure between the safety valve 1 and the heat pipe 5.

[0095] The shape, number, and arrangement of the tanks 3 mounted on the vehicle 2 are not limited to the above examples. For example, only one tank 3 may be mounted on the vehicle 2. In this case, the common pipe 52 is omitted. Further, the high-pressure gas accommodated inside the tank 3 may be the fuel of the vehicle 2 and is not limited to hydrogen gas. That is, the vehicle 2 is not limited to a fuel cell vehicle.

[0096] The safety valve 1 may be attached to a portion other than the end portions 3f and 3r of the tank 3, or may be attached to only one of the end portions 3f and 3r. Further, the specific structure of the safety valve 1 is not limited to that shown in FIG. 2. For example, the sensing portion that opens the discharge port 6d in the safety valve 1 as the temperature rises may be formed of a member other than the above-described cylinder 12.

[0097] The shape and arrangement of the heat pipe 5 are not limited to the above examples and may be appropriately changed according to the shape and arrangement of the tank 3, the structure and arrangement of the safety valve 1, and the like. For example, the main pipe 51 may extend upward or horizontally from the safety valve 1 attached to the end portions 3f and 3r of the tank 3 and then extend along the intermediate portion 3c. Further, the common pipe 52 may extend along a discharge pipe that discharges the high-pressure gas discharged from the safety valve 1 to the outside of the vehicle 2 instead of the above-described gas supply pipe 28. Note that in the safety device 10, either the main pipe 51 or the common pipe 52 may be omitted.

[0098] The configuration of the above-described collar 7 is an example. The collar 7 may be formed in an appropriate shape according to the shape of the housing 6 of the safety valve 1, the position of the sensing portion, and the like. Further, the collar 7 may be attached to a portion different from the cap 14 of the housing 6. The protective member 8 illustrated in FIG. 3 is applicable to various heat pipes 5. For example, the protective member 8 may be provided to cover the common pipe 52. Further, the protective member 8 may be applied to the various heat pipes 5 illustrated in FIGS. 9 to 11. Furthermore, the protective member 8 may be applied only to a part of the heat pipe 5 where an impact can be inputted.

[0099] [4. Supplementary Note] Disclose the supplementary note regarding the above embodiment.

[0100] (Supplementary Note 1) A safety device for a high-pressure gas tank that houses high-pressure gas as fuel for a vehicle, a safety valve attached to the high-pressure gas tank and configured to discharge the high-pressure gas from inside the high-pressure gas tank to the outside as the temperature rises; a heat pipe connected to the safety valve and configured to transfer heat by evaporation and condensation of a working fluid enclosed therein and capillary action of a wick provided on an inner wall. A safety device for a high-pressure gas tank, characterized by the above.

[0101] (Supplementary Note 2) The high-pressure gas tank has a cylindrical intermediate portion and a pair of hemispherical end portions formed on both sides of the intermediate portion, the safety valve is attached to at least one of the end portions, the heat pipe includes a main pipe extending along the intermediate portion from the safety valve attached to the end portion. A safety device for a high-pressure gas tank according to Supplementary Note 1, characterized by the above.

[0102] (Supplementary Note 3) The high-pressure gas tank is mounted on the vehicle in a posture where the center of the intermediate portion extends in the horizontal direction, the main pipe extends downward from the safety valve attached to the end portion and then extends along the intermediate portion. A safety device for a high-pressure gas tank according to Supplementary Note 2, characterized by the above.

[0103] (Appended Note 4) The high-pressure gas tank is mounted on the vehicle in a posture where the center of the middle part extends in the vertical direction, The safety valve is attached to the upper end portion, The main pipe extends obliquely downward from the safety valve attached to the end portion and then extends along the middle part. The safety device for a high-pressure gas tank according to Appended Note 2, characterized in that.

[0104] (Appended Note 5) The high-pressure gas tank is installed outside the vehicle width direction of the chassis frame behind the cab of the vehicle, The heat pipe is provided in the space between the chassis frame and the high-pressure gas tank. The safety device for a high-pressure gas tank according to any one of Appended Notes 1 to 4, characterized in that.

[0105] (Appended Note 6) The high-pressure gas tank is installed between the cab and the rear body of the vehicle, The heat pipe is provided in the space between the rear body and the high-pressure gas tank. The safety device for a high-pressure gas tank according to any one of Appended Notes 1 to 4, characterized in that.

[0106] (Appended Note 7) Comprising the safety valves respectively attached to a plurality of the high-pressure gas tanks, The heat pipe includes a common pipe thermally conductively connected to each of the safety valves. The safety device for a high-pressure gas tank according to any one of Appended Notes 1 to 6, characterized in that.

[0107] (Appended Note 8) The common pipe extends along a gas supply pipe connected to a plurality of the high-pressure gas tanks for sending the high-pressure gas to a predetermined supply destination. The safety device for a high-pressure gas tank according to appended note 7, characterized by the following.

[0108] (Appended note 9) The common pipe extends along the vehicle height direction and is thermally conductively connected to each of the safety valves respectively attached to the plurality of high-pressure gas tanks arranged in the vehicle height direction. The safety device for a high-pressure gas tank according to appended note 7 or 8, characterized by the following.

[0109] (Appended note 10) The common pipe extends along the vehicle width direction and is thermally conductively connected to each of the safety valves respectively attached to the plurality of high-pressure gas tanks arranged in the vehicle width direction. The safety device for a high-pressure gas tank according to appended note 7 or 8, characterized by the following.

[0110] (Appended note 11) The safety valve has a sensing part that opens a discharge port for discharging the high-pressure gas to the outside as the temperature rises, a housing that houses the sensing part, and a first connection part that is a hole or groove formed at a part adjacent to the sensing part in the housing. The heat pipe is connected to the first connection part. The safety device for a high-pressure gas tank according to any one of appended notes 1 to 10, characterized by the following.

[0111] (Appended note 12) The safety valve has a sensing part that opens a discharge port for discharging the high-pressure gas to the outside as the temperature rises, and a housing that houses the sensing part. The safety valve further includes a collar made of a material having a higher thermal conductivity than the housing, attached to the housing, and having a second connection part that is a hole or groove formed at a position adjacent to the sensing part. The heat pipe is connected to the second connection part. The safety device for a high-pressure gas tank according to any one of appended notes 1 to 10, characterized by the following.

[0112] (Supplementary Note 13) It further includes a protective member formed in a plate shape or a lattice shape with a plurality of holes formed therein, covering the heat pipe. The safety device for a high-pressure gas tank according to any one of Supplementary Notes 1 to 12, characterized in that.

[0113] (Supplementary Note 14) The vehicle is a fuel cell vehicle that drives a motor for running with the power of a fuel cell, The high-pressure gas tank is a hydrogen tank that stores hydrogen gas as the high-pressure gas inside. The safety device for a high-pressure gas tank according to any one of Supplementary Notes 1 to 13, characterized in that.

Explanation of Reference Numerals

[0114] 1 Safety valve 2 Vehicle (fuel cell vehicle) 3 High-pressure gas tank (hydrogen tank) 3A First tank 3B Second tank 3c Intermediate part 3d Tank center (center of the intermediate part) 3f End part (front end part, upper end part) 3r End part (rear end part, lower end part) 4 Heat exchanger 5 Heat pipe 6 Housing 6a Inlet port 6b Outlet port 6c Gas passage 6d Discharge port 6e Discharge passage 7 Collar 7a Mounting part 7b Arm part 8 Protective member 9 Fan 10 Safety device (safety device for high-pressure gas tank) 11 Plunger 12 Cylinder (sensing part) 13 Body part 14 Cap 15 Housing hole (first connection part) 16 Color hole (second connection part) 17 Coupling block 18 Spring 21 Cab 22 Chassis frame 23 Fuel cell 24 Motor 25 High-voltage battery 26 Side rail 27 Cross member 28 Gas supply pipe 29 Rear body 30 Tank box 31 Downstream pipe 32 Side cover 34 Front wheel 35 Rear wheel 37 Outer surface 38 Mount 39 Stay 51 Main pipe 52 Common pipe D1 Vehicle length direction (front-rear direction) D2 Vehicle width direction (left-right direction) D3 Vehicle height direction (up-down direction)

Claims

1. A safety device for a high-pressure gas tank that stores high-pressure gas as vehicle fuel inside, a safety valve attached to the high-pressure gas tank that discharges the high-pressure gas from inside the high-pressure gas tank to the outside as the temperature rises; and a heat pipe connected to the safety valve that transfers heat by evaporation and condensation of a working fluid enclosed inside and capillary action of a wick provided on the inner wall. A safety device for a high-pressure gas tank, characterized by the above.

2. The high-pressure gas tank has a cylindrical intermediate portion and a pair of hemispherical end portions formed on both sides of the intermediate portion, the safety valve is attached to at least one of the end portions, and the heat pipe includes a main pipe extending along the intermediate portion from the safety valve attached to the end portion. The safety device for a high-pressure gas tank according to claim 1, characterized by the above.

3. The high-pressure gas tank is mounted on the vehicle in a posture where the center of the intermediate portion extends in the horizontal direction, and the main pipe extends along the intermediate portion after extending downward from the safety valve attached to the end portion. The safety device for a high-pressure gas tank according to claim 2, characterized by the above.

4. The high-pressure gas tank is mounted on the vehicle in a posture where the center of the intermediate portion extends in the vertical direction, the safety valve is attached to the upper end portion, and the main pipe extends along the intermediate portion after extending obliquely downward from the safety valve attached to the end portion. The safety device for a high-pressure gas tank according to claim 2, characterized by the above.

5. The high-pressure gas tank is installed outside the vehicle width direction of the chassis frame behind the cab of the vehicle, The heat pipe is provided in the space between the chassis frame and the high-pressure gas tank. The safety device for a high-pressure gas tank according to claim 1, characterized in that.

6. The high-pressure gas tank is installed between the cab and the rear body of the vehicle, The heat pipe is provided in the space between the rear body and the high-pressure gas tank. The safety device for a high-pressure gas tank according to claim 1, characterized in that.

7. It includes safety valves respectively attached to a plurality of the high-pressure gas tanks, The heat pipe includes a common pipe thermally connected to each of the safety valves. The safety device for a high-pressure gas tank according to claim 1, characterized in that.

8. The common pipe extends along a gas supply pipe connected to a plurality of the high-pressure gas tanks for sending the high-pressure gas to a predetermined supply destination. The safety device for a high-pressure gas tank according to claim 7, characterized in that.

9. The common pipe extends along the vehicle height direction and is thermally connected to each of the safety valves respectively attached to a plurality of the high-pressure gas tanks arranged in the vehicle height direction. The safety device for a high-pressure gas tank according to claim 7, characterized in that.

10. The common pipe extends along the vehicle width direction and is thermally connected to each of the safety valves respectively attached to a plurality of the high-pressure gas tanks arranged in the vehicle width direction. The safety device for a high-pressure gas tank according to claim 7, characterized in that.

11. The safety valve has a sensing portion that opens a discharge port for discharging the high-pressure gas to the outside as the temperature rises, a housing that houses the sensing portion, and a first connection portion that is a hole or groove formed in a portion of the housing adjacent to the sensing portion. The heat pipe is connected to the first connection portion. The safety device for a high-pressure gas tank according to claim 1, characterized in that.

12. The safety valve has a sensing portion that opens a discharge port for discharging the high-pressure gas to the outside as the temperature rises, and a housing that houses the sensing portion. The safety valve further includes a collar formed of a material having a higher thermal conductivity than the housing, attached to the housing, and having a second connection portion that is a hole or groove formed at a position adjacent to the sensing portion. The heat pipe is connected to the second connection portion. The safety device for a high-pressure gas tank according to claim 1, characterized in that.

13. The safety device for a high-pressure gas tank according to claim 1, further comprising a protective member formed in a plate shape or a lattice shape with a large number of holes formed therein and covering the heat pipe. The safety device for a high-pressure gas tank according to claim 1, characterized in that.

14. The vehicle is a fuel cell vehicle that drives a motor for running with the power of a fuel cell. The high-pressure gas tank is a hydrogen tank that stores hydrogen gas as the high-pressure gas therein. The safety device for a high-pressure gas tank according to claim 1, characterized in that.

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