High-pressure tank

Abstract

To provide a high pressure tank capable of storing fuel gas.SOLUTION: A high pressure tank comprises a tank body, a strain sensor provided in the tank body, and a storage unit provided in the tank body. The storage unit is configured to be able to store the number of times that the high-pressure tank is filled with fuel gas, which is counted based on a strain amount by the strain sensor.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a high-pressure tank for storing fuel gas. [Background technology]

[0002] 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. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-44863 Summary of the Invention [Problem to be solved by the invention]

[0004] Because high-pressure tanks repeatedly expand and contract as gas is filled and released, they must be replaced when the number of fills reaches a predetermined number. In some cases, used high-pressure tanks are used. However, the technology of 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 makes it difficult to guarantee the lifespan of used high-pressure tanks, for example, because there is a possibility that the number of fills may not be properly transferred or may have been tampered with. [Means for solving the problem]

[0005] The present specification discloses a high-pressure tank comprising 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 be capable of storing the number of times the high-pressure tank has been refilled with fuel gas, which is counted based on the amount of strain measured by the strain sensor.

[0006] According to the above structure, the tank body is provided with a memory unit capable of storing the number of times the fuel gas has been refilled. This allows the high-pressure tank itself to retain the number of times it has been refilled. 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, it is possible to guarantee the lifespan of the high-pressure tank. This makes it possible to optimize the life cycle of the high-pressure tank.

[0007] 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 inside and outside 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. Since the nozzle structure and the diaphragm structure can be shared, the number of parts can be reduced. This enables the strain sensor to be made smaller and less expensive.

[0008] 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 flange. The strain sensor may be disposed 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. The nozzle structure and the diaphragm structure can be shared, making it possible to reduce the number of parts. This allows for the strain sensor to be made smaller and less expensive.

[0009] A vehicle may include the high-pressure tank according to claim 1. The vehicle may include a control unit configured to be able to communicate with the storage unit. The control unit may be configured to be able to notify the user when the number of fillings received from the storage 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.

[0010] Details and further improvements of the technology disclosed in this specification are described in the following "Description of Embodiments of the Invention." [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic cross-sectional view of a hydrogen tank 10. [Figure 2] FIG. 2 is an enlarged cross-sectional view of the vicinity of a second base 42. [Figure 3] FIG. 10 is an enlarged cross-sectional view of a hydrogen tank 210 according to a second embodiment. [Figure 4] FIG. 10 is an enlarged cross-sectional view of the vicinity of a second base 42 according to a modified example. DETAILED DESCRIPTION OF THE INVENTION [Example]

[0012] <Configuration of Hydrogen Tank 10> Figure 1 shows a schematic cross-sectional view of a hydrogen tank 10. The hydrogen tank 10 stores, for example, high-pressure hydrogen and is used as a supply source for supplying hydrogen 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 make up the tank body.

[0013] The liner 20 is a member that forms the inner layer of the hydrogen tank 10 and has a hollow cylindrical shape. The liner 20 is a resin container for storing hydrogen gas. An opening 21 is formed at the end of the liner 20 in the -x direction, and an opening 22 is formed at the end of the liner 20 in the +x direction. The reinforcing layer 30 is a layer that is formed on the outer peripheral surface of the liner 20 and reinforces the liner 20. The reinforcing layer 30 is an outer layer that includes, for example, a fiber-reinforced resin. The reinforcing layer 30 is formed, for example, from carbon fiber reinforced plastic (CFRP).

[0014] The first nozzle 41 is a substantially cylindrical member. The first nozzle 41 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 in 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 passage and the outlet passage are provided with a main stop valve, a manual valve, a check valve, etc. (not shown).

[0015] The second mouthpiece 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 mouthpiece 42. The flange 42f is formed around the entire outer periphery of the second mouthpiece 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.

[0016] The bottom of jig hole 42j1 and the bottom of jig hole 42j2 are arranged opposite each other with strain detection unit 43 interposed therebetween. In other words, strain detection unit 43 arranged at the bottom of jig hole 42j1 functions as a partition wall separating the inside and outside of hydrogen tank 10. Therefore, second mouthpiece 42 does not communicate with the inside of liner 20. Note that components such as strain sensor 44 and memory unit 47 arranged inside jig hole 42j1 are not shown in FIG.

[0017] <Configuration of the vicinity of the second cap 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 ease 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.

[0018] 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 jig hole 42j1. Jig hole 42j1 is a hole used when forming reinforcing layer 30, and is not used after the tank body is completed. Therefore, by using jig hole 42j1 as a container for storing these components, the size of hydrogen tank 10 can be reduced. Furthermore, even if an external force is applied due to a vehicle collision, etc., second mouthpiece 42 can protect these components.

[0019] The strain detection unit 43 is a member that separates the jig holes 42j1 and 42j2. A recess 43r is formed in the strain detection unit 43. The recess 43r deforms due to pressure, causing the strain detection unit 43 to function as a diaphragm. The strain detection unit 43 is formed separately from the second mouthpiece 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.

[0020] The housing 46 has a screw 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. The housing 46 also has an opening 46a through which the lead wire 45 can pass.

[0021] 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. Lead wires 45 send the electrical signal from the strain sensor 44 to a memory unit 47.

[0022] The storage unit 47 includes a CPU 47c and a 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 storage unit 47 will be described later.

[0023] The light emitting unit 49 is a part that can be controlled to be turned on or off based on a command from the CPU 47c. In this embodiment, the light emitting unit 49 is an LED.

[0024] 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 a vehicle ECU 63 by 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 a component for notifying the user of various information. The external communication interface 65 is a component for performing various communication CM with an external hydrogen station 70. The communication CM is not particularly limited and may be wireless communication or wired communication via a cable.

[0025] <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.

[0026] The CPU 47c then monitors fluctuations in the pressure applied to the strain detection unit 43 to count the number of times hydrogen gas has been filled. The method for counting the number of times the filling has occurred is not particularly limited, and various methods can be used. In this embodiment, the CPU 47c monitors whether the pressure has risen above a predetermined filling threshold. If the pressure rise value exceeds the filling threshold, it can be determined that hydrogen gas has been filled. In this case, the CPU 47c increments the number of times the filling has occurred, which is stored in the nonvolatile memory 47m.

[0027] The refill threshold value may be set to be 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.

[0028] The number of fills stored in non-volatile memory 47m is transmitted to vehicle ECU 63 via internal connector 48, external connector 61, and harness 62. 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, vehicle ECU 63 displays a warning on display 64 indicating that the life of hydrogen tank 10 is nearing the end. This notifies the user that hydrogen tank 10 needs to be replaced. This allows the hydrogen tank 10 to be used safely.

[0029] Furthermore, before the hydrogen station 70 starts filling the hydrogen tank 10 with hydrogen, the vehicle ECU 63 executes a communication command (CM) with the hydrogen station 70. If the number of fillings has reached a predetermined number, the vehicle ECU 63 limits the hydrogen filling. For example, it may lower the maximum filling amount or disable filling altogether. This makes it possible to prevent accidents caused by hydrogen tanks 10 that are nearing the end of their life.

[0030] 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.

[0031] <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. Used high-pressure tanks are sometimes used. However, conventional technology does not allow for the number of fills to be directly linked to the high-pressure tank. This makes it difficult to properly manage the lifespan of used hydrogen tanks. This makes it difficult to guarantee the lifespan of used hydrogen tanks, for example, because of the possibility that the number of fills may not be properly transferred 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 require that they satisfy a very high safety factor as a test condition (e.g., be able to withstand approximately 11,000 fills). This safety factor is excessive, which increases the manufacturing cost, size, weight, and other factors of the hydrogen tank. Therefore, the hydrogen tank 10 described in this specification is designed with a memory unit 47 in the tank body that can store the number of fuel gas fills. This allows the hydrogen tank 10 itself to retain the number of fills, thereby enabling proper management of the lifespan of the hydrogen tank 10. 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.

[0032] In the hydrogen tank 10 of this specification, a memory unit 47 is disposed inside the second mouthpiece 42 that constitutes the tank body. In other words, the memory unit 47 is configured integrally 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.

[0033] In the hydrogen tank 10 of this specification, the strain detection unit 43, which functions as a partition wall, can be made to function as a diaphragm for detecting the amount of strain. Because the structure of the second mouthpiece 42 and the diaphragm can be shared, it is possible to reduce the number of parts, and it is possible to make the hydrogen tank 10 smaller and less expensive.

[0034] Conventionally, pressure sensors have been installed via valves or piping, which can result in pressure loss due to narrow or long flow paths. In the hydrogen tank 10 of this specification, the strain sensor 44 can be installed without the need for valves or piping. This makes it possible to suppress pressure loss caused by the sensor installation structure. [Example]

[0035] <Configuration of Hydrogen Tank 210> 3 shows an enlarged cross-sectional view of the vicinity of the second mouthpiece 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.

[0036] 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.

[0037] Flange 42f is a plate-like member that protrudes outward from the outer peripheral surface of second mouthpiece 42. Therefore, as the internal pressure of 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 hydrogen tank 210 decreases, it deforms toward the inside of the tank (toward arrow A2), with base BA as the fulcrum. In other words, flange 42f can function as a cantilevered diaphragm. The strain sensor 44 can measure the amount of strain in flange 42f.

[0038] <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 likely to deform 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.

[0039] 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 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 these objectives alone is technically useful.

[0040] <Modification> The structure of the strain detection unit 43 is not limited to the examples 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 structure can be shared, the number of parts can be reduced.

[0041] The part 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.

[0042] The technology of this specification is not limited to the hydrogen tank 10 that is filled with hydrogen gas. The technology of this specification can be applied to any high-pressure tank that can be filled with various objects. For example, it can also be applied to a high-pressure tank that is filled with CNG (compressed natural gas).

[0043] 2 is an example. For example, a hermetic seal may be provided between the housing 46 and the lead wire 45.

[0044] The strain detector 43 is an example of a partition wall. The vehicle ECU 63 is an example of a control unit. [Explanation of symbols]

[0045] 10: Hydrogen tank 20: Liner 30: Reinforcement layer 41: First nozzle 41h: Through hole 42: Second nozzle 42j1, 42j2: Jig holes 42f: Flange 43: Detection unit 44: Strain sensor 45: Lead wire 47: Storage unit 47c: CPU 47m: Non-volatile memory 63: Vehicle ECU

Claims

1. 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.

2. 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.

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