Boil-off gas recovery system for hydrogen vehicle including liquefied hydrogen tank and recovery method using same

Abstract

According to an embodiment of the present disclosure, disclosed is a boil-off gas (BOG) recovery system comprising: a liquefied hydrogen storage tank (10) configured to accommodate liquefied hydrogen; a metal hydride tank (20) configured to store BOG generated from the liquefied hydrogen storage tank (10); a fuel cell (30) connected to the liquefied hydrogen storage tank (10) through a first hydrogen supply line (100); a second hydrogen supply line (200) having one end connected to the metal hydride tank (20) and the other end connected to one point on the first hydrogen supply line (100); a first charging line (110) connecting the liquefied hydrogen storage tank (10) and a first receptacle (11); a BOG transport line (120) having one end connected to one point (P1) on the first charging line (110) and the other end connected to one point (P2) on the second hydrogen supply line (200); and a heat circulation line (300) formed such that at least a portion thereof exchanges heat with the fuel cell (30) and at least another portion thereof exchanges heat with the metal hydride tank (20).

Description

A system for recovering evaporative gas from a hydrogen vehicle including a liquefied hydrogen tank and a method for recovering the same

[0001] The present disclosure relates to a system and method for recovering evaporative gas of a hydrogen vehicle including a liquid hydrogen tank, and more particularly, to a system and method capable of supplying hydrogen by storing evaporative gas of a hydrogen vehicle as a metal hydride and releasing hydrogen from the stored metal hydride using heat generated from a fuel cell.

[0002]

[0003] Hydrogen is a future clean energy source that can replace fossil fuels. Liquid hydrogen, in particular, offers high energy density and light weight, making it ideal for a wide range of applications, including space propulsion fuel, magnetic imaging medical equipment, cryopreservation of medical organs, and hydrogen commercial vehicles. Liquid hydrogen can be cryogenically stored at -253 degrees Celsius at atmospheric pressure, at a concentration of 70.8 grams per liter. This reduces the volume of hydrogen gas to 1 / 800th of that of conventional hydrogen gas.

[0004] In particular, when applying liquid hydrogen to hydrogen commercial vehicles, the vehicle is operated with electricity generated from the fuel cell, which has the advantages of low cost, high performance, and short charging time. At this time, although the liquid hydrogen must be maintained at a temperature of -253 degrees Celsius, 3 to 5% of boil-off gas (BOG) is generated per day due to the influence of the external temperature and the insulation performance of the liquid hydrogen storage tank after charging, and the BOG is released to the outside to maintain the pressure of the liquid hydrogen storage tank. Therefore, there is a need to develop a technology that can prevent hydrogen fuel loss by utilizing the BOG continuously generated after charging the liquid hydrogen. The present inventors have developed an evaporative gas recovery system for hydrogen vehicles that can improve the operation and energy efficiency of the system by recovering and storing the BOG and supplying the stored hydrogen to the fuel cell using the heat generated from the fuel cell.

[0005]

[0006] Review relevant patent literature.

[0007] Korean Patent No. 10-2522896 relates to an integrated cooling and vaporization system for a hydrogen fuel cell vehicle that mutually exchanges the coolant required for cooling the fuel cell and the heat transfer medium required for vaporizing liquid hydrogen. However, the problem of fuel loss due to continuously occurring BOG is not resolved.

[0008] Korean Patent Publication No. 10-2020-0012074 relates to a boil-off gas treatment system that recovers the cold energy of boil-off gas generated in a hydrogen carrier and stores it in a tank filled with a hydrogen-capturing metal. However, since the BOG is stored in a separate metal tank and not utilized, there is a limit to securing high energy efficiency.

[0009] (Patent Document 1) Korean Patent No. 10-2522896

[0010] (Patent Document 2) Korean Patent Publication No. 10-2020-0012074

[0011]

[0012] Accordingly, the present disclosure aims to provide a system and recovery method capable of recovering BOG by re-storing BOG generated in a liquefied hydrogen storage tank and utilizing the stored BOG as an auxiliary hydrogen supply source.

[0013] In addition, the present disclosure seeks to provide a method for efficiently securing thermal energy required for hydrogen release from a metal hydride tank, thereby improving the operation and energy efficiency of the system.

[0014] In addition, the present disclosure is intended to provide a system and recovery method that can improve the driving distance by recovering BOG generated during storage of liquefied hydrogen, by applying it to a hydrogen vehicle including a liquefied hydrogen tank.

[0015] The problems to be solved by the present disclosure are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0016]

[0017] According to one embodiment of the present disclosure, a liquid hydrogen storage tank (10) configured to receive liquid hydrogen, a metal hydride tank (20) configured to store BOG (Boil Off Gas) generated in the liquid hydrogen storage tank (10), a fuel cell (30) connected to the liquid hydrogen storage tank (10) through a first hydrogen supply line (100), a second hydrogen supply line (200) having one end connected to the metal hydride tank (20) and the other end connected to a point on the first hydrogen supply line (100), a first charging line (110) connecting the liquid hydrogen storage tank (10) and a first receptacle (11), a BOG transport line (120) having one end connected to a point (P1) on the first charging line (110) and the other end connected to a point (P2) on the second hydrogen supply line (200), and at least a part of the BOG transport line (120) A system for recovering evaporated gas is provided, which includes a heat circulation line (300) configured to exchange heat with a fuel cell (30) and at least a portion of which exchanges heat with the metal hydride tank (20).

[0018] In addition, it is preferable to further include a second charging line (111) connecting the liquid hydrogen storage tank (10) and the second receptacle (12), a charging connection line (112) connecting a point on the second charging line (111) and another point (P3) formed at the rear of the point (P1) on the first charging line (110), and a relief valve (V1) arranged on the charging connection line (112) and configured to control the opening and closing of the charging connection line (112).

[0019] In addition, on the first charging line (110), a pressure sensor (13) configured to sense the internal hydraulic pressure of the first charging line (110) is disposed at the rear of the other point (P3), a check valve (V2) configured to control the flow from the liquid hydrogen storage tank (10) to the first receptacle (11) is further disposed at the front of the one point (P1), and it is preferable that the relief valve (V1) is opened when the pressure of the fluid measured by the pressure sensor (13) is higher than a preset pressure.

[0020] In addition, on the second hydrogen supply line (200), a first valve (V3) is disposed in front of the point where the second hydrogen supply line (200) and the other end of the BOG transport line (120) meet, and a second valve (V4) is disposed in the rear of the point where the second hydrogen supply line (200) and the other end of the BOG transport line (120) meet, and it is preferable that a first regulator (14) is disposed on the BOG transport line (120).

[0021] In addition, it is preferable that a second regulator (21) be placed on the first hydrogen supply line (100) at the rear of the point where the first hydrogen supply line (100) and the second hydrogen supply line (200) are connected.

[0022] In addition, in the evaporation gas recovery method using the evaporation gas recovery system of the present disclosure, the method is provided, including: (a) a step of measuring the pressure of the fluid flowing in the first charging line (110) by the pressure sensor (13), (b) a step of comparing the pressure value measured by the pressure sensor (13) in step (a) with a preset pressure value by the ECU (40), (c-1) a step of repeating step (a) when the measured pressure value is determined to be less than the preset pressure value in step (b), and (c-2) a step of opening the relief valve (V1) when the measured pressure value is determined to be equal to or greater than the preset pressure value in step (b).

[0023] In addition, the recovery method according to the present disclosure preferably includes a step of (d) storing the fluid flowing through the BOG transport line (120) in the metal hydride tank (20) when the first valve (V3) is opened and the second valve (V4) is closed, a step of (e-1) providing heat energy generated in the fuel cell (30) to the metal hydride tank (20) through the heat circulation line (300), and a step of (e-2) supplying the fluid stored in the metal hydride tank (20) to the fuel cell (30) through the second hydrogen supply line (200) and the first hydrogen supply line (100) when the first valve (V3) and the second valve (V4) are opened.

[0024]

[0025] As described above, according to one embodiment of the present disclosure, BOG generated in a liquid hydrogen storage tank is stored as a metal hydride, and the metal hydride is heated to supply hydrogen to a user, thereby recovering BOG generated in the liquid hydrogen storage tank, thereby reducing fuel loss.

[0026] Additionally, the heat generated from the fuel cell is used as a thermal energy source to separate hydrogen from metal hydride through heat exchange with the fuel cell coolant, and the vaporized hydrogen can be supplied to the fuel cell.

[0027] In addition, by recovering and reusing BOG generated when storing liquid hydrogen in transportation vehicles that use hydrogen as an energy source (hydrogen commercial vehicles, hydrogen electric vehicles, etc.), trains, ships, and aircraft, the driving distance per charge can be improved.

[0028] Additionally, when supplying hydrogen to a fuel cell from a liquid hydrogen storage tank, BOG stored in a metal hydride tank can be supplied to the fuel cell as an auxiliary fuel. Therefore, if the liquid hydrogen fuel in the liquid hydrogen storage tank is insufficient, fuel can be supplemented from the metal hydride tank. Therefore, redundancy can be ensured.

[0029]

[0030] FIG. 1 is a conceptual diagram illustrating an evaporation gas recovery system of a hydrogen vehicle including a liquid hydrogen tank according to one embodiment of the present disclosure.

[0031] Fig. 2 is a schematic block diagram for explaining the features in which each component in the system of Fig. 1 is connected to and controlled by the ECU (40).

[0032] FIG. 3 is a flowchart of a recovery method using an evaporative gas recovery system of a hydrogen vehicle including a liquid hydrogen tank according to one embodiment of the present disclosure.

[0033]

[0034] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings. When designating components in each drawing, it should be noted that, where possible, identical components are given identical reference numerals, even if they appear in different drawings. Furthermore, in describing the present disclosure, detailed descriptions of related known structures or functions will be omitted if they are deemed to obscure the gist of the present disclosure.

[0035] In describing components of embodiments according to the present disclosure, symbols such as first, second, i), ii), a), b) may be used. These symbols are only for distinguishing the components from other components, and the nature, order, or sequence of the components are not limited by the symbols. When a part in the specification is said to "include" or "have" a component, this does not mean that other components are excluded, but rather that other components may be included, unless explicitly stated otherwise.

[0036] In the present disclosure, "upstream" means a point where the flow distance of hydrogen is relatively short in a certain flow path. For example, in FIG. 1, it may mean a point where the movement distance is relatively short when the fluid flows (moves) in the direction from the receptacle (11, 12) toward the tank (10) on each charging line (110, 111). In addition, it may mean a point where the movement distance is relatively short when the fluid flows in the direction from the first charging line (110) toward the second hydrogen supply line (200) on the BOG transport line (120). In addition, it may mean a point where the movement distance is relatively short when the fluid flows (moves) in the direction from the tank (10, 20) toward the fuel cell (30) on each hydrogen supply line (100, 200).

[0037] In addition, in the present disclosure, "downstream" means a point where the flow distance of hydrogen is relatively long in a certain flow path. For example, in FIG. 1, it may mean a point where the travel distance is relatively long when the fluid flows (moves) in the direction from the receptacle (11, 12) toward the tank (10) on each of the charging lines (110, 111). In addition, it may mean a point where the travel distance is relatively long when the fluid flows in the direction from the first charging line (110) toward the second hydrogen supply line (200) on the BOG transport line (120). In addition, it may mean a point where the travel distance is relatively long when the fluid flows (moves) in the direction from the tank (10, 20) toward the fuel cell (30) on each of the hydrogen supply lines (100, 200). Meanwhile, it should be noted that in the present disclosure, front and rear may not only mean adjacent areas, but may also refer to points where the travel distances are different even at separate points.

[0038]

[0039] 1. Description of the composition

[0040] FIG. 1 is a conceptual diagram illustrating an evaporative gas recovery system for a hydrogen vehicle including a liquid hydrogen tank according to one embodiment of the present disclosure. FIG. 2 is a schematic block diagram illustrating a feature in which each component of the system of FIG. 1 is connected to and controlled by an ECU (electric control unit, 40).

[0041]

[0042] Referring to FIGS. 1 and 2, an evaporation gas recovery system of a hydrogen vehicle including a liquid hydrogen tank according to one embodiment of the present disclosure includes a liquid hydrogen storage tank (10), a metal hydride tank (20), a fuel cell (30), an ECU (40), and a heater (50).

[0043]

[0044] The liquid hydrogen storage tank (10) is configured to accommodate liquid hydrogen and hydrogen boil-off gas (hereinafter referred to as 'BOG' (Boil Off Gas)) generated therefrom, and stores liquid hydrogen supplied from an external source at an ultra-low temperature. One or more liquid hydrogen storage tanks (10) may be provided in a means of transportation (vehicle, ship, etc.) for transportation efficiency, and may be insulated to be suitable for transporting liquid hydrogen at an ultra-low temperature that is prone to evaporation.

[0045] One end of the first hydrogen supply line (100) is connected to a liquid hydrogen storage tank (10), and the other end is connected to a fuel cell (30), so that the liquid hydrogen storage tank (10) and the fuel cell (30) are connected through the first hydrogen supply line (100), and the liquid hydrogen stored in the liquid hydrogen storage tank (10) flows and is supplied to the fuel cell (30).

[0046]

[0047] The first receptacle (11) and the second receptacle (12) are a type of connector for injecting liquid hydrogen into a vehicle, and the liquid hydrogen injected into the first receptacle (11) and the second receptacle (12) is stored in a liquid hydrogen storage tank (10). Meanwhile, the vehicle that is charged with liquid hydrogen through the receptacles (11, 12) may be a means of transportation that uses hydrogen as fuel, such as a hydrogen commercial vehicle, a hydrogen electric vehicle, a ship, an aircraft, or a hydrogen demand source that includes a fuel cell (30).

[0048]

[0049] The metal hydride tank (20) is configured to store BOG generated in the liquid hydrogen storage tank (10) by being filled with a hydrogen-absorbing metal therein. The hydrogen-absorbing metal stores BOG as a metal hydride, and can separate hydrogen from the metal hydride by heating and release it in a gaseous state. One or more metal hydride tanks (20) can be provided to store BOG, which can vary depending on the external environment or the insulation performance (10) of the liquid hydrogen storage tank, and hydrogen can be stored in the form of a metal hydride by an absorption process and stored at a high density under room temperature and low pressure conditions.

[0050] The second hydrogen supply line (200) has one end connected to the metal hydride tank (20) and the other end connected to a point on the first hydrogen supply line (100), so that the fluid stored in the metal hydride tank (20) flows to the other end of the first hydrogen supply line (100) and is supplied to the fuel cell (30).

[0051]

[0052] The second regulator (21) is placed on the first hydrogen supply line (100), behind the point where the first hydrogen supply line (100) and the second hydrogen supply line (200) are connected. The second regulator (21) controls the flow rate of hydrogen gas flowing into the fuel cell (30) from the first hydrogen supply line (100).

[0053] The first regulator (14) is placed on the BOG transport line (120) and controls the flow rate of hydrogen gas flowing from the first charging line (110) to the second hydrogen supply line (200).

[0054]

[0055] One end of the BOG transport line (120) is connected to a point (P1) on the first charging line (110), and the other end is connected to a point (P2) on the second hydrogen supply line (200). The BOG transport line (120) is formed so that the BOG generated from the liquid hydrogen storage tank (10) and flowing on the first charging line (110) flows toward the metal hydride tank (20) through the second hydrogen supply line (200). A device capable of maintaining a certain pressure is installed on the BOG transport line (120), thereby controlling the flow rate of the BOG, thereby increasing the absorption efficiency of the metal hydride tank (20). For example, an orifice may be provided on the BOG transport line (120).

[0056] Since the BOG transport line (120) is formed to branch off from a point of the first charging line (110) instead of directly connecting the liquid hydrogen storage tank (10) and the metal hydride tank (20), it has the advantage of allowing for flow design within a limited layout. This has the effect of providing a separate hydrogen storage system without changing the size of the evaporative gas recovery system of a vehicle or ship.

[0057]

[0058] The first charging line (110) is configured to connect the liquid hydrogen storage tank (10) and the first receptacle (11), thereby transferring the liquid hydrogen supplied to the vehicle through the first receptacle (11) to the liquid hydrogen storage tank (10). Meanwhile, all or part of the hydrogen gas generated in the liquid hydrogen storage tank (10) may be discharged to the outside of the liquid hydrogen storage tank (10) through the first charging line (110).

[0059] The second charging line (111) is configured to connect the liquid hydrogen storage tank (10) and the second receptacle (12), thereby transferring the liquid hydrogen supplied to the vehicle through the second receptacle (12) to the liquid hydrogen storage tank (10).

[0060] A check valve may be arranged on the first charging line (110) or the second charging line (111), respectively, to independently control the flow of hydrogen from the liquid hydrogen storage tank (10). As one embodiment of the present disclosure, a check valve (V2) is arranged on the first charging line (110), in front of a point (P1), and is configured to control the flow from the liquid hydrogen storage tank (10) to the first receptacle (11).

[0061]

[0062] The charging connection line (112) connects a point on the second charging line (111) and another point (P3) formed behind a point (P1) on the first charging line (110).

[0063] The pressure sensor (13) is a sensor that is placed at the rear of another point (P3) on the first charging line (110) and measures the internal hydraulic pressure of the first charging line (110).

[0064] A relief valve (V1) is positioned on the charging connection line (112) and controls the opening and closing of the charging connection line (112), thereby maintaining the hydraulic pressure inside the first charging line (110) at a constant pressure. The opening and closing of the relief valve (V1) is controlled according to the fluid pressure value of the first charging line (110) measured by the pressure sensor (13). A detailed description thereof will be provided later.

[0065] Meanwhile, in the present disclosure, the relief valve (V1) is preferably a normally closed type valve. This allows the relief valve (V1) to open when a separate electrical signal is present.

[0066]

[0067] The first valve (V3) is arranged in front of the point where the second hydrogen supply line (200) and the other end of the BOG transport line (120) meet and is configured to control the opening and closing of the BOG transport line (120). Due to the first valve (V3), the inflow of hydrogen from the BOG transport line (120) to the metal hydride tank (20) can be controlled.

[0068] The second valve (V4) is arranged at the rear of the point where the second hydrogen supply line (200) and the other end of the BOG transport line (120) meet and is configured to control the opening and closing of the BOG transport line (120). Due to the second valve (V4), the inflow of hydrogen into the first hydrogen supply line (100) can be controlled.

[0069]

[0070] The fuel cell (30) is connected to the liquid hydrogen storage tank (10) through the first hydrogen supply line (100), and is connected to the metal hydride tank (20) through the second hydrogen supply line (200). The fuel cell (30) is an electrochemical device that converts the chemical energy of hydrogen and oxygen into electrical energy, and can generate electricity by receiving hydrogen gas from the first hydrogen supply line (100) or the second hydrogen supply line (200). The heat generated in the fuel cell (30) can be collected by the heat circulation line (300) and transmitted and utilized to equipment requiring heating.

[0071] The heat circulation line (300) is formed so that at least a portion thereof exchanges heat with the fuel cell (30), and at least another portion thereof exchanges heat with the metal hydride tank (20). Heat generated in the fuel cell (30) is recovered from the cooling water circulating in the heat circulation line (300), and the recovered heat is transferred and supplied to the metal hydride tank (20) to heat the metal hydride tank (20).

[0072]

[0073] The ECU (40) is electrically connected to a pressure sensor (13), a level sensor (not shown), a relief valve (V1), a first valve (V3), a second valve (V4), and a heater (50), and is configured to receive sensing values ​​from each component or transmit a control signal to each component (see Fig. 2).

[0074]

[0075] The ECU (40) receives the pressure value of the fluid on the first charging line (110) measured from the pressure sensor (13), compares it with the preset pressure value, and outputs an opening / closing signal of the relief valve (V1). If the fluid pressure value of the first charging line (110) measured by the pressure sensor (13) is higher than the preset pressure value, the relief valve (V1) is opened, so that at least a portion of the fluid flowing in the first charging line (110) can flow to the second charging line (111). If the fluid pressure value of the first charging line (110) measured by the pressure sensor (13) is determined to be lower than the preset pressure value, the relief valve (V1) is closed, so that the hydrogen gas generated in the liquid hydrogen storage tank (10) can flow only to the first charging line (110).

[0076]

[0077] The ECU (40) can selectively control the flow path of hydrogen gas moving on the BOG transport line (120) by independently controlling the opening and closing of the first valve (V3) and the second valve (V4). By a control signal of the ECU (40), the hydrogen gas can flow along a path including at least one of a path passing through the second hydrogen supply line (200) to flow to the metal hydride tank (20) or a path passing through the second hydrogen supply line (200) to join the first hydrogen supply line (100) and be supplied to the fuel cell (30).

[0078] In addition, a level sensor (not shown) provided in the liquid hydrogen storage tank (10) measures the level of liquid hydrogen stored inside the liquid hydrogen storage tank (10) and transmits the level measurement value to the ECU (40). The ECU (40) compares the level measurement value measured from the level sensor (not shown) with a preset level value and controls the opening and closing of the first valve (V3) and the second valve (V4), thereby allowing hydrogen gas to be supplied to the fuel cell (30) auxiliary. For example, when the level measurement value measured from the level sensor (not shown) is lower than the preset level value, the ECU (40) can open the first valve (V3) and the second valve (V4) to supply hydrogen gas. That is, when the liquid hydrogen fuel stored in the liquid hydrogen storage tank (10) is insufficient, redundancy can be secured by supplying hydrogen gas to the fuel cell (30) from the metal hydride tank (20).

[0079]

[0080] When there is a fuel cell charging signal, the ECU (40) operates the heater (50) to heat the liquid hydrogen storage tank (10) and provide hydrogen gas to the fuel cell (30).

[0081]

[0082] A heater (50) is installed adjacent to a liquid hydrogen storage tank (10) and heats the liquid hydrogen storage tank (10). The liquid hydrogen is heated to generate vaporized hydrogen gas, and the vaporized hydrogen gas is supplied to the first hydrogen supply line (100). The heater (50) may use a heating method using induction heating or a PTC heater, etc.

[0083]

[0084] 2. Recovery method using an evaporation gas recovery system

[0085] FIG. 3 is a flowchart for explaining a recovery method using an evaporation gas recovery system of a hydrogen vehicle including a liquid hydrogen tank according to one embodiment of the present disclosure.

[0086]

[0087] Referring to Fig. 3, the method and process for recovering evaporated gas are described in detail.

[0088] After liquefied hydrogen is stored in the liquefied hydrogen storage tank (10), the pressure of hydrogen gas flowing through the first charging line (110) is measured by the pressure sensor (13) (S300).

[0089] Information about the pressure measured at step S300 is transmitted as an electrical signal to the ECU (40) and compared with a preset pressure by the ECU (40) (S310). At this time, the preset pressure is a value input by the manufacturer or user and can be appropriately designed and changed.

[0090] If the pressure value measured by the pressure sensor (13) is determined to be less than the preset pressure value, steps S300 to S310 are repeated.

[0091] If the pressure value measured by the pressure sensor (13) is determined to be higher than the preset pressure value, the relief valve (V1) is opened (S320).

[0092] Thereafter, the pressure of the fluid flowing through the first charging line (110) is measured by the pressure sensor (13). Thereafter, the newly measured pressure value is compared again with the preset pressure by the ECU (40).

[0093]

[0094] Hereinafter, with reference to FIG. 1, a method and process for recovering evaporated gas according to the opening and closing of the first valve (V3) and the second valve (V4) will be described.

[0095]

[0096] When the first valve (V3) is open and the second valve (V4) is closed, hydrogen gas flowing through the BOG transport line (120) can be stored in the metal hydride tank (20).

[0097]

[0098] When the first valve (V3) and the second valve (V4) are open, hydrogen stored in the metal hydride tank (20) can be supplied to the fuel cell (30).

[0099] The ECU (40) can provide thermal energy to the metal hydride tank (20) by controlling all or part of the devices provided in the thermal circulation line (300). Specifically, the ECU (40) can drive a pump or heat exchanger provided on the thermal circulation line (300) so that thermal energy generated in the fuel cell (30) is provided to the metal hydride tank (20) through the thermal circulation line (300). The metal hydride tank (20) can receive heat from the thermal circulation line (300) and release gaseous hydrogen from the metal hydride.

[0100] When the metal hydride tank (20) exchanges heat with the heat circulation line (300) and the first valve (V3) and the second valve (V4) are opened, the hydrogen stored in the metal hydride tank (20) flows in a gaseous state and passes through the second hydrogen supply line (200) and the first hydrogen supply line (100) to be supplied to the fuel cell (30).

[0101] As described above, the ECU (40) controls the opening and closing of the first valve (V3) and the second valve (V4), so that when the liquid hydrogen fuel stored in the liquid hydrogen storage tank (10) is insufficient, hydrogen gas from the metal hydride tank (20) can be supplied auxiliary to the fuel cell (30).

[0102]

[0103] Meanwhile, when there is insufficient space to store hydrogen in the metal hydride tank (20), the first valve (V3) and the second valve (V4) are closed and the relief valve (V1) is opened, so that hydrogen gas generated in the liquefied hydrogen storage tank (10) can be re-introduced into the liquefied hydrogen storage tank (10).

[0104]

[0105] The boiling point of hydrogen is approximately -253 degrees Celsius, and various devices and pipes connecting each component of the evaporation gas recovery system of a hydrogen vehicle including a liquefied hydrogen tank according to one embodiment of the present disclosure may be insulated.

[0106]

[0107] The above description is merely an example of the technical idea of ​​one embodiment according to the present disclosure, and those skilled in the art to which the present embodiment pertains may make various modifications and variations without departing from the essential characteristics of the present embodiment. Therefore, the present embodiments are not intended to limit the technical idea of ​​the present embodiment but to explain it, and the scope of the technical idea of ​​the present embodiment is not limited by these embodiments. The protection scope of the present embodiment should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of rights of the present embodiment.

[0108]

[0109] (Explanation of symbols)

[0110] 10: Liquid hydrogen storage tank

[0111] 11: First receptacle

[0112] 12: Second receptacle

[0113] 13: Pressure sensor

[0114] 14: First regulator

[0115] 20: Metal hydride tank

[0116] 21: Second Regulator

[0117] 30: Fuel cell

[0118] 40: ECU

[0119] 50: Heater

[0120] 100: First hydrogen supply line

[0121] 110: 1st charging line

[0122] 111: Second charging line

[0123] 112: Charging connection line

[0124] 120: BOG transport line

[0125] 200: Second hydrogen supply line

[0126] 300: Thermal circulation line

[0127] V1: Relief valve

[0128] V2: Check valve

[0129] V3: First valve

[0130] V4: Second valve

Claims

1. A liquid hydrogen storage tank (10) configured to accommodate liquid hydrogen; A metal hydride tank (20) configured to store BOG (Boil Off Gas) generated from the above liquefied hydrogen storage tank (10); A fuel cell (30) connected through the above liquid hydrogen storage tank (10) and the first hydrogen supply line (100); A second hydrogen supply line (200) having one end connected to the metal hydride tank (20) and the other end connected to a point on the first hydrogen supply line (100); A first charging line (110) connecting the above liquid hydrogen storage tank (10) and the first receptacle (11); A BOG transport line (120) having one end connected to a point (P1) on the first charging line (110) and the other end connected to a point (P2) on the second hydrogen supply line (200); and A heat circulation line (300) is formed such that at least a part thereof exchanges heat with the fuel cell (30) and at least another part thereof exchanges heat with the metal hydride tank (20). Evaporative gas recovery system.

2. In paragraph 1, A second charging line (111) connecting the above liquid hydrogen storage tank (10) and the second receptacle (12); A charging connection line (112) connecting a point on the second charging line (111) and another point (P3) formed behind the point (P1) on the first charging line (110); and Further comprising a relief valve (V1) arranged on the charging connection line (112) and configured to control the opening and closing of the charging connection line (112); Evaporative gas recovery system.

3. In paragraph 2, On the above first charging line (110), At the rear of the above other point (P3), a pressure sensor (13) configured to sense the internal hydraulic pressure of the first charging line (110) is placed, A check valve (V2) configured to block the flow from the above liquid hydrogen storage tank (10) to the first receptacle (11) is further arranged in front of the above point (P1). The above relief valve (V1) opens when the pressure of the fluid measured by the pressure sensor (13) is higher than the preset pressure. Evaporative gas recovery system.

4. In paragraph 3, On the above second hydrogen supply line (200), A first valve (V3) arranged in front of the point where the second hydrogen supply line (200) and the other end of the BOG transport line (120) meet; and A second valve (V4) is arranged at the rear of the point where the second hydrogen supply line (200) and the other end of the BOG transport line (120) meet; On the above BOG transport line (120), a first regulator (14) is placed. Evaporative gas recovery system.

5. In paragraph 1, On the first hydrogen supply line (100), a second regulator (21) is placed behind the point where the first hydrogen supply line (100) and the second hydrogen supply line (200) are connected. Evaporative gas recovery system.

6. In a method for recovering evaporated gas using an evaporated gas recovery system according to Article 3 or Article 4, (a) A step in which the pressure of the fluid flowing through the first charging line (110) is measured by the pressure sensor (13); (b) a step in which the pressure value measured by the pressure sensor (13) in step (a) is compared with a preset pressure value by the ECU (40); (c-1) In step (b), if it is determined that the measured pressure value is less than the preset pressure value, step (a) is repeated; and (c-2) In the step (b), if it is determined that the measured pressure value is higher than the preset pressure value, a step of opening the relief valve (V1) is included; How to recover.

7. In the method for recovering evaporated gas using the evaporated gas recovery system according to Article 4, (d) a step in which the fluid flowing through the BOG transport line (120) is stored in the metal hydride tank (20) when the first valve (V3) is opened and the second valve (V4) is closed; (e-1) a step in which the heat energy generated from the fuel cell (30) is provided to the metal hydride tank (20) through the heat circulation line (300); and (e-2) a step in which, when the first valve (V3) and the second valve (V4) are opened, the fluid stored in the metal hydride tank (20) is supplied to the fuel cell (30) through the second hydrogen supply line (200) and the first hydrogen supply line (100); How to recover.

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