JP7743819B2 - High-pressure tank - Google Patents

Description

The technology disclosed in this specification relates to a high-pressure tank for storing fuel gas.

Patent Document 1 discloses a high-pressure tank equipped with a strain gauge. The strain gauge is connected to a pressure measurement unit. The pressure measurement unit calculates the internal pressure of the high-pressure tank using the strain value received from the strain gauge. By monitoring the internal pressure with the pressure measurement unit, the number of times fuel gas has been refilled can be calculated.

JP 2019-44863 A

High-pressure tanks repeatedly expand and contract as gas is filled and released, so they need to be replaced when a certain number of fills is reached. There are also cases where second-hand high-pressure tanks are used. However, the technology in Patent Document 1 does not allow the calculated number of fills to be linked to the high-pressure tank. As a result, the lifespan of the high-pressure tank cannot be properly managed. This means, for example, that the number of fills may not be transferred correctly, or the number of fills may have been tampered with, making it difficult to guarantee the lifespan of a second-hand high-pressure tank.

The high-pressure tank disclosed in this specification comprises a tank body, a strain sensor provided in the tank body, and a memory unit provided in the tank body. The memory unit is configured to store the number of times the high-pressure tank has been refilled with fuel gas, counted based on the amount of strain measured by the strain sensor.

With the above structure, the tank body is equipped with a memory unit that can store the number of times the fuel gas has been refilled. This allows the high-pressure tank itself to retain the number of refills. This makes it possible to properly manage the lifespan of the high-pressure tank. Therefore, for example, even if the high-pressure tank is removed from the vehicle and used as a second-hand item, the lifespan of the high-pressure tank can be guaranteed. This makes it possible to optimize the life cycle of the high-pressure tank.

The tank body may include a liner, a reinforcing layer covering the outer periphery of the liner, and a nozzle attached to the liner and having a jig hole into which a jig can be engaged. A partition wall separating the interior and exterior of the high-pressure tank may be disposed at the bottom of the jig hole. The strain sensor may be disposed in the partition wall. The partition wall portion is thinner than the portion where the jig hole is not formed, and is therefore an area that is easily deformed in response to the internal pressure of the high-pressure tank. Therefore, the partition wall can function as a diaphragm for detecting the amount of strain. Because the nozzle structure and diaphragm structure can be shared, the number of parts can be reduced. This enables the strain sensor to be made smaller and less expensive.

The tank body may comprise a liner, a reinforcing layer covering the outer periphery of the liner, and a nozzle attached to the liner and having a flange. The strain sensor may be located on the flange. The flange portion is thinner than the main body portion of the nozzle, and is therefore an area that is easily deformed in response to the internal pressure of the high-pressure tank. In other words, the flange is highly sensitive to displacement due to internal pressure, and can therefore function as a diaphragm for detecting the amount of strain. Because the nozzle structure and diaphragm structure can be shared, the number of parts can be reduced. This enables the strain sensor to be made smaller and less expensive.

A vehicle may be equipped with the high-pressure tank described in claim 1. The vehicle may also be equipped with a control unit configured to be able to communicate with the memory unit. The control unit may be configured to be able to notify the user when the number of refills received from the memory unit has reached a predetermined number. This allows the user to recognize that the high-pressure tank needs to be replaced. This allows the high-pressure tank to be used safely.

Details and further improvements to the technology disclosed in this specification are explained in the "Description of Embodiments" below.

1 is a schematic cross-sectional view of a hydrogen tank 10. FIG. FIG. 2 is an enlarged cross-sectional view of the vicinity of the second nozzle 42. FIG. 10 is an enlarged cross-sectional view of a hydrogen tank 210 according to a second embodiment. FIG. 10 is an enlarged cross-sectional view of the vicinity of a second base 42 according to a modified example.

<Configuration of hydrogen tank 10>
1 shows a schematic cross-sectional view of a hydrogen tank 10. The hydrogen tank 10 is used, for example, to store high-pressure hydrogen and supply it to a fuel cell. The hydrogen tank 10 comprises a liner 20, a reinforcing layer 30, a first nozzle 41, and a second nozzle 42. These components form the tank body.

The liner 20 is a hollow cylindrical member that forms the inner layer of the hydrogen tank 10. The liner 20 is a resin container for storing hydrogen gas. An opening 21 is formed at the end of the liner 20 facing in the -x direction, and an opening 22 is formed at the end facing in the +x direction. The reinforcing layer 30 is a layer formed on the outer peripheral surface of the liner 20 that reinforces the liner 20. The reinforcing layer 30 is an outer layer that contains, for example, fiber-reinforced resin. The reinforcing layer 30 is formed, for example, from carbon fiber-reinforced plastic (CFRP).

The first nozzle 41 is a substantially cylindrical member. It has a through-hole 41h and a flange 41f. The flange 41f is a brim-shaped member that protrudes outward from the outer periphery of the first nozzle 41. The flange 41f is formed around the entire outer periphery of the first nozzle 41. The flange 41f is fixed integrally with the liner 20 so as to close the opening 21 of the liner 20. The through-hole 41h is connected to the interior of the liner 20. A valve assembly (not shown) is screwed into and fixed into the through-hole 41h. The valve assembly has an inlet passage and an outlet passage. The inlet passage is a passage for filling the hydrogen tank 10 with hydrogen from an external hydrogen source. The outlet passage is a passage for supplying hydrogen from the hydrogen tank 10 to a fuel cell (not shown). The inlet and outlet passages are also equipped with a main stop valve, a manual valve, a check valve, and other valves (not shown).

The second nozzle 42 has jig holes 42j1 and 42j2 and a flange 42f. The flange 42f is a brim-shaped member that protrudes outward from the outer periphery of the second nozzle 42. The flange 42f is formed around the entire outer periphery of the second nozzle 42. The flange 42f is fixed integrally with the liner 20 so as to close the opening 22 of the liner 20. A jig (not shown) engages with the jig hole 42j1. The jig allows the hydrogen tank 10 to be rotatably held during the process of forming the reinforcing layer 30 on the hydrogen tank 10.

The bottom of jig hole 42j1 and the bottom of jig hole 42j2 are positioned opposite each other with the strain detection unit 43 interposed between them. In other words, the strain detection unit 43 positioned at the bottom of jig hole 42j1 functions as a partition wall separating the inside and outside of the hydrogen tank 10. Therefore, the second mouthpiece 42 is not in communication with the inside of the liner 20. Note that components such as the strain sensor 44 and memory unit 47 positioned inside jig hole 42j1 are not shown in Figure 1.

<Configuration in the vicinity of the second base 42>
2 shows an enlarged cross-sectional view of the vicinity of the second base 42. The second base 42 is equipped with a strain detection unit 43, a strain sensor 44, lead wires 45, a housing 46, a memory unit 47, an internal connector 48, and a light-emitting unit 49. For convenience of illustration, the second base 42, strain detection unit 43, strain sensor 44, and housing 46 are shown in cross-section, and the other parts are shown in a simple block diagram.

The strain detection unit 43, strain sensor 44, lead wires 45, housing 46, memory unit 47, internal connector 48, and light-emitting unit 49 are arranged inside the jig hole 42j1. The jig hole 42j1 is used when forming the reinforcing layer 30, and is not used after the tank body is completed. Therefore, by reusing the jig hole 42j1 as a container for storing these components, the size of the hydrogen tank 10 can be reduced. Furthermore, the second nozzle 42 can protect these components even when external forces are applied, such as during a vehicle collision.

The strain detection unit 43 is a component that separates the jig holes 42j1 and 42j2. A recess 43r is formed in the strain detection unit 43. The recess 43r deforms under pressure, causing the strain detection unit 43 to function as a diaphragm. The strain detection unit 43 is constructed separately from the second nozzle 42. This allows for a wider range of materials to be selected for the strain detection unit 43. By selecting a material with good pressure-strain characteristics, the detection accuracy of the strain detection unit 43 can be improved. The strain detection unit 43 may also be coated with a hydrogen permeation-resistant coating. This makes it possible to suppress changes in output characteristics due to hydrogen permeation.

The housing 46 has a threaded portion 46s. By screwing the housing 46 in the -x direction, the strain sensor 43 can be pressed against the bottom surface 42b of the jig hole 42j1 and fixed in place. The housing 46 also has an opening 46a through which the lead wire 45 can pass.

The strain sensor 44 is disposed in the strain detection unit 43, which functions as a partition wall. The strain sensor 44 converts the displacement of the strain detection unit 43 into an electrical signal and outputs it. The strain sensor 44 includes a strain gauge and a sensor chip (not shown). In this embodiment, the strain gauge is a metal strain gauge having a metal resistor. The lead wire 45 sends the electrical signal from the strain sensor 44 to the memory unit 47.

The memory unit 47 includes a CPU 47c and non-volatile memory 47m. The CPU 47c calculates the pressure applied to the strain detection unit 43 by the hydrogen inside the hydrogen tank 10 based on the amount of strain measured by the strain sensor 44. The CPU 47c also counts the number of times the hydrogen tank 10 has been filled with hydrogen gas, and stores the counted number of times in the non-volatile memory 47m. The detailed operation of the memory unit 47 will be described later.

The light-emitting unit 49 is a component that can be controlled to turn on or off based on commands from the CPU 47c. In this embodiment, the light-emitting unit 49 is an LED.

The internal connector 48 is connected to the memory unit 47. An external connector 61 is engaged with the internal connector 48. The external connector 61 is connected to the vehicle ECU 63 via a harness 62. This configures a vehicle in which the vehicle ECU 63 and the memory unit 47 can communicate with each other. The vehicle ECU 63 is connected to a display 64 and an external communication interface 65. The display 64 is located in the driver's seat and is used to notify the user of various information. The external communication interface 65 is used to perform various communication CMs with an external hydrogen station 70. The communication CMs are not particularly limited and may be wireless or wired communication via a cable.

<Operation of hydrogen tank 10>
An example of the operation of counting the number of times hydrogen gas has been filled into the hydrogen tank 10 will be described. When the strain detection unit 43 deforms due to the pressure of hydrogen inside the hydrogen tank 10, the strain gauge provided in the strain sensor 44 also deforms at the same rate, causing a change in the resistance value of the resistor. The change in resistance value is detected by the sensor chip and converted into a strain value. The converted strain value is sent to the memory unit 47 via the lead wire 45. The CPU 47c of the memory unit 47 uses the received strain value to calculate the pressure applied to the strain detection unit 43 by the hydrogen inside the hydrogen tank 10. Note that the method of calculating the pressure is not particularly limited. For example, the internal pressure of the hydrogen tank 10 may be converted using a map that associates the amount of strain with pressure. The map may be stored in advance in the non-volatile memory 47m.

The CPU 47c then counts the number of times hydrogen gas has been filled by monitoring fluctuations in the pressure applied to the strain detection unit 43. There are no particular limitations on the method for counting the number of fills, and various methods can be used. In this embodiment, the CPU 47c monitors whether the pressure has risen beyond a predetermined fill threshold. If the pressure rise value exceeds the fill threshold, it can be determined that hydrogen gas has been filled. In this case, the CPU 47c counts up the number of fills stored in the non-volatile memory 47m by one.

The refill threshold should be set to a value greater than the maximum pressure increase that can occur due to temperature changes, etc. This prevents errors in counting the number of refills due to pressure fluctuations.

The number of fills stored in the non-volatile memory 47m is transmitted to the vehicle ECU 63 via the internal connector 48, external connector 61, and harness 62. The vehicle ECU 63 monitors whether the number of fills has reached a predetermined number. The predetermined number may be set appropriately based on the safety factor of the hydrogen tank 10. If the number of fills has reached the predetermined number, the vehicle ECU 63 displays a warning on the display 64 indicating that the hydrogen tank 10 is nearing the end of its life. This notifies the user that the hydrogen tank 10 needs to be replaced. The hydrogen tank 10 can be used safely.

Furthermore, before starting to fill the hydrogen tank 10 with hydrogen at the hydrogen station 70, the vehicle ECU 63 executes a communication CM with the hydrogen station 70. If the number of fills has reached a predetermined number, the vehicle ECU 63 limits the filling of hydrogen. For example, it reduces the maximum fill amount or makes it impossible to fill the hydrogen tank at all. This makes it possible to prevent accidents caused by hydrogen tanks 10 that are nearing the end of their life.

The CPU 47c of the memory unit 47 controls the light-emitting unit 49 to light up while the pressure detected by the strain detection unit 43 is higher than the safety threshold, and to turn off while the pressure is lower than the safety threshold. The safety threshold may be set in advance to a value that ensures the safety of workers when replacing, disposing of, or transporting the hydrogen tank 10. In this embodiment, the safety threshold is set to 1 MPa. This allows workers to easily check the internal pressure state of the hydrogen tank 10 by checking whether the light-emitting unit 49 is lit. This makes it possible to ensure work safety while reducing the amount of work required to measure the internal pressure of the hydrogen tank 10.

<Effects>
The following describes the problem. Because hydrogen tanks repeatedly expand and contract as gas is filled and released, they must be replaced when a predetermined number of fills is reached. In some cases, used high-pressure tanks are used. However, conventional technology has not been able to directly link the number of fills to the high-pressure tank. This has made it difficult to properly manage the lifespan of used hydrogen tanks. This has made it difficult to guarantee the lifespan of used hydrogen tanks, for example, due to the possibility that the number of fills may not be transferred properly or that the number of fills may have been falsified. Therefore, to ensure the safety of hydrogen tanks even when the number of fills is unknown, regulations have imposed a very high safety factor as a testing condition (e.g., the tank must be able to withstand approximately 11,000 fills). This safety factor is excessive, which has the problem of increasing the manufacturing cost, size, weight, etc. of the hydrogen tank. Therefore, the hydrogen tank 10 described in this specification is structured so that a memory unit 47 capable of storing the number of fuel gas fills is provided in the tank body. This allows the hydrogen tank 10 itself to retain the number of fills, thereby enabling the lifespan of the hydrogen tank 10 to be properly managed. Since the number of refills can be accurately determined, it is possible to control the life cycle of the hydrogen tank 10, assuming tank replacement. This allows the safety factor to be optimized, making it possible to reduce the manufacturing cost, size, weight, etc. of the hydrogen tank 10.

In the hydrogen tank 10 of this specification, a memory unit 47 is located inside the second mouthpiece 42 that constitutes the tank body. In other words, the memory unit 47 is configured as one unit with the hydrogen tank 10. This makes it possible to reliably transfer the number of fills even when the hydrogen tank 10 is removed or installed in another vehicle. Furthermore, because it is difficult to disassemble the second mouthpiece 42 and remove the memory unit 47, it is possible to prevent tampering with the number of fills.

In the hydrogen tank 10 of this specification, the strain detection unit 43, which functions as a partition wall, can function as a diaphragm for detecting the amount of strain. Because the structure of the second mouthpiece 42 and the diaphragm can be shared, the number of parts can be reduced. This allows for the hydrogen tank 10 to be made smaller and less expensive.

In the past, pressure sensors were installed via valves or piping, which could result in pressure loss due to narrowing or lengthening of the flow path. With the hydrogen tank 10 described in this specification, the strain sensor 44 can be installed without using valves or piping. This makes it possible to suppress pressure loss caused by the sensor installation structure.

<Configuration of hydrogen tank 210>
3 shows an enlarged cross-sectional view of the vicinity of the second nozzle 42 in the hydrogen tank 210 of Example 2. The hydrogen tank 210 of Example 2 differs from the hydrogen tank 10 of Example 1 in the position of the strain sensor 44. Components that are common between the hydrogen tank 210 and the hydrogen tank 10 are given the same reference numerals, and descriptions thereof will be omitted.

The strain sensor 44 is disposed on the outer surface of the flange 42f. The strain sensor 44 is fixed by being sandwiched between the flange 42f and the reinforcing layer 30. A memory unit 47, an internal connector 48, and a light-emitting unit 49 are disposed inside the jig hole 42j1. The strain sensor 44 is connected to the memory unit 47 by a lead wire 45.

The flange 42f is a plate-shaped member that protrudes outward from the outer peripheral surface of the second nozzle 42. Therefore, as the internal pressure of the hydrogen tank 210 increases, it deforms toward the outside of the tank (toward arrow A1), with base BA as the fulcrum. Furthermore, as the internal pressure of the hydrogen tank 210 decreases, it deforms toward the inside of the tank (toward arrow A2), with base BA as the fulcrum. In other words, the flange 42f can function as a cantilevered diaphragm. The amount of strain in the flange 42f can then be measured by the strain sensor 44.

<Effects>
The strain detection unit 43 of Example 1 functions as a diaphragm in which the entire outer periphery of the recessed portion 43r is supported. On the other hand, the flange 42f of Example 2 functions as a cantilevered diaphragm. A cantilevered diaphragm is more susceptible to deformation because it has a free end. In other words, a cantilevered diaphragm is more sensitive to displacement due to the internal pressure of the hydrogen tank 210. Therefore, the hydrogen tank 210 of Example 2 can further improve the sensitivity of measuring internal pressure. Furthermore, because the structure of the second mouthpiece 42 and the diaphragm structure can be shared, the number of parts can be reduced. This enables the hydrogen tank 210 to be made smaller and at a lower cost.

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

<Modification>
The structure of the strain detection unit 43 is not limited to the example described in this specification and may be various. For example, as shown in FIG. 4 , a partition wall 42w may be formed at a position facing the bottom of the jig hole 42j1 and the bottom of the jig hole 42j2. A strain sensor 44 may be attached to the partition wall 42w. The partition wall 42w is a part formed integrally with the second nozzle 42 and functions as a diaphragm. The strain amount of the partition wall 42w can be measured by the strain sensor 44. Because the structure of the second nozzle 42 and the diaphragm can be shared, the number of parts can be reduced.

The location that counts the number of times hydrogen gas has been filled is not limited to the memory unit 47. For example, the pressure value measured by the strain sensor 44 may be transmitted to the vehicle ECU 63 via the harness 62. The number of times hydrogen gas has been filled may be counted by the vehicle ECU 63 based on pressure fluctuations in the hydrogen tank 10. The number of times hydrogen gas has been filled counted by the vehicle ECU 63 may be transmitted to the memory unit 47 via the harness 62 and stored in non-volatile memory 47m.

The technology described herein is not limited to hydrogen tanks 10 filled with hydrogen gas. It can be applied to any high-pressure tank that can be filled with a variety of objects. For example, it can also be applied to high-pressure tanks filled with CNG (compressed natural gas).

The structure shown in Figure 2 is an example. For example, a hermetic seal may be provided to seal between the housing 46 and the lead wire 45.

The strain detection unit 43 is an example of a partition wall. The vehicle ECU 63 is an example of a control unit.

10: Hydrogen tank 20: Liner 30: Reinforcement layer 41: First nozzle 41h: Through hole 42: Second nozzle 42j1, 42j2: Jig holes 42f: Flange 43: Detector 44: Strain sensor 45: Lead wire 47: Storage unit 47c: CPU 47m: Non-volatile memory 63: Vehicle ECU

Claims (2)

a cylindrical liner;
a reinforcing layer covering the outer periphery of the liner;
a first nozzle attached to one end side of the liner, the first nozzle having a gas inlet passage and a gas outlet passage;
a second nozzle attached to the other end of the liner, the second nozzle having a jig hole that can be engaged with a jig and that communicates between the inside and outside of the liner ;
a partition wall disposed inside the jig hole and separating the inside and outside of the liner, the partition wall being formed separately from the second nozzle;
a strain sensor provided in the partition wall ;
A high-pressure tank comprising:
The partition wall has a recess formed therein,
The strain sensor is located within a region in which the recessed portion is formed.
High pressure tank. a cylindrical liner;
a first nozzle attached to one end side of the liner, the first nozzle having a gas inlet passage and a gas outlet passage;
a second nozzle attached to the other end of the liner ;
a plate-shaped flange formed around the entire outer periphery of the second base and protruding outward from the outer periphery of the second base;
a reinforcing layer covering the outer periphery of the liner and the surface of the flange;
a strain sensor disposed on the surface of the flange, the strain sensor being fixed by being sandwiched between the flange and the reinforcing layer;
A high-pressure tank comprising:
the flange deforms outward from the high-pressure tank with the base as a fulcrum in response to an increase in internal pressure of the high-pressure tank, and deforms inward from the high-pressure tank with the base as a fulcrum in response to a decrease in internal pressure of the high-pressure tank,
The strain sensor is located closer to the outer periphery of the flange than the base.
High pressure tank.