Thermal management system and method for cold start of cryogenic fuel supply device for fuel cell

Abstract

The present invention relates to a thermal management system of a device for supplying hydrogen to a fuel cell, and disclosed are a thermal management system and method for the cold start of a cryogenic fuel supply device for a fuel cell, in which liquid hydrogen is vaporized into gaseous hydrogen by using waste heat of a fuel cell coolant, and the gaseous hydrogen is supplied to a fuel cell, and at the same time, residual heat of the coolant may be removed (cooled) by using cold energy emitted when the liquid hydrogen is vaporized, and thus generated heat of the fuel cell may be efficiently managed.

Description

Thermal management system and method for cold starting of a cryogenic fuel supply device for a fuel cell

[0001] The present invention relates to a thermal management system for a device for supplying hydrogen to a fuel cell, and more particularly, to a thermal management system and method for cold starting of a cryogenic fuel supply device for a fuel cell, which can efficiently manage the heat generated by the fuel cell by vaporizing liquid hydrogen into gaseous hydrogen using waste heat of a fuel cell coolant and supplying it to the fuel cell, and at the same time removing (cooling) residual heat of the coolant using cold heat released when the liquid hydrogen vaporizes.

[0002] Today, hydrogen fuel cells are gaining attention as a highly energy-efficient and environmentally friendly energy source compared to conventional internal combustion engines because they generate power through the electrochemical reaction of hydrogen and oxygen, and the only product is water.

[0003] In particular, in the automobile industry, due to increasing emission regulations, hydrogen fuel cell vehicles, which operate by using electricity generated by reacting hydrogen and oxygen in the air instead of gasoline internal combustion engines, are attracting attention as next-generation eco-friendly vehicles, and active research is being conducted by various automobile manufacturers.

[0004] These hydrogen fuel cell vehicles, drones, micro-mobility, and other various means of transportation that use hydrogen as fuel and oxygen as an oxidizer use a fuel cell stack as a power source that generates electrical energy by chemically reacting hydrogen fuel in a gaseous or liquid state supplied from a hydrogen tank with oxygen in the air. Therefore, there is no emission of pollutants such as exhaust fumes, so there is no environmental pollution. In addition, they are more energy efficient than other fuels, so they can travel long distances with less fuel.

[0005] Currently, in the automotive industry, efforts are being made to apply hydrogen fuel storage and supply systems to large trucks that emit large amounts of greenhouse gases as hydrogen fuel cell technology advances. Liquid hydrogen-based fuel storage and supply systems, which can overcome the limitations of electric vehicles and increase the efficiency of long-distance, eco-friendly transportation, are emerging as strategically important core technologies.

[0006] Meanwhile, the fuel cell system of a hydrogen fuel cell vehicle is composed of a fuel cell stack that generates electrical energy from an electrochemical reaction of hydrogen and oxygen, a hydrogen supply device that supplies hydrogen as fuel to the fuel cell stack, an oxygen supply device that supplies oxygen (air) as an oxidizer necessary for the electrochemical reaction to the fuel cell stack, a thermal management system that optimally controls the operating temperature of the fuel cell stack by releasing heat, a byproduct of the electrochemical reaction of the fuel cell stack, to the outside, and a controller that controls the overall operation of the fuel cell system.

[0007] Here, the process of releasing high-density liquefied hydrogen from the hydrogen tank of the hydrogen supply device and changing its phase is an endothermic reaction, so in order to smoothly supply high-purity hydrogen to the fuel cell stack, it is necessary to supply heat of vaporization from the outside.

[0008] That is, liquid hydrogen is transformed into a gaseous state using an external heat source and then supplied to the fuel cell.

[0009] Typically, to convert liquefied hydrogen stored in a liquid hydrogen fuel storage tank into a state suitable for the fuel inlet conditions of a fuel cell system, processes such as flow rate control, phase change, and pressure control are required. At this time, air-cooling and water-cooling heat exchange processes are required as phase change methods to convert liquefied hydrogen into gaseous hydrogen.

[0010] Air-cooled vaporizers suffer from the disadvantages of moisture in the atmosphere, which can cause freezing in pipes and other areas during heat exchange. Furthermore, the use of air requires a large heat transfer surface area, and controlling air flow increases power consumption. Water-cooled vaporizers require continuous refrigerant circulation, requiring a space-consuming refrigerant circulation system. This, in turn, increases operating and installation costs.

[0011] Meanwhile, hydrogen fuel cell vehicles can improve the efficiency of the entire system by applying an integrated thermal management system that includes heat removal and cooling methods for the fuel cell stack.

[0012] For example, fuel cells continuously remove heat generated above a certain level by circulating coolant that lowers the temperature of the fuel cell using a cooling device to maintain the temperature within the normal operating range during operation.

[0013] [Prior Art Literature]

[0014] [Patent Document]

[0015] (Patent Document 1) KR 10-2522896 B1 2023. 04. 13.

[0016] (Patent Document 2) KR 10-2567867 B1 2023. 08. 11.

[0017] Accordingly, the inventor of the present invention comprehensively considered all the above-mentioned matters and, at the same time, sought to solve the technical limitations and problems of the thermal management system of the existing fuel cell hydrogen supply device, and made great efforts to develop a thermal management system for cold starting of a new structure of a cryogenic fuel supply device for a fuel cell, which can efficiently manage the heat generated by the fuel cell and maximize energy efficiency by utilizing the heat load removed or supplied to maintain the fuel cell at the normal operating temperature and the waste heat (residual heat) of the fuel cell coolant as energy required to vaporize liquid hydrogen, and at the same time utilizing the cold heat released when the liquid hydrogen vaporizes as energy required to cool the coolant. As a result, the inventor of the present invention was created.

[0018] Therefore, the technical problem and purpose to be solved by the present invention is to provide a thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell, which can maximize energy efficiency by utilizing the heat load of the fuel cell coolant and the cold heat of liquid hydrogen as energy required for vaporization and cooling.

[0019] The technical problems and objectives to be solved by the present invention are not limited to the technical problems and objectives mentioned above, and other technical problems and objectives not mentioned will be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0020] In order to effectively achieve a specific technical purpose while embodying a new idea for solving the technical problem of the present invention as described above, a specific means according to an embodiment of the present invention is a fuel cell that produces electric energy by supplying gaseous hydrogen and oxygen and reacting them, a hydrogen fuel tank that stores and supplies liquid hydrogen, a double-pipe type first heat exchanger in which liquid hydrogen is supplied from the hydrogen fuel tank to the inner tube through a first hydrogen line, and coolant is supplied to the outer tube through a first refrigerant line to reduce the heat load generated during the operation of the fuel cell and maintain it at a normal operating temperature range, a second heat exchanger in which a tube is built in a shell connected to the outer tube of the first heat exchanger and in which coolant flows, one end of which is connected to the inner tube of the first heat exchanger and in which liquid hydrogen flows, gaseous hydrogen flowing in the inner tube connected to the other end of the tube is supplied to the fuel cell through a second hydrogen line, and coolant flowing in the outer tube connected to the shell of the second heat exchanger is supplied to the fuel cell through a second refrigerant line. A thermal management system for cold start of a cryogenic fuel supply device for a fuel cell is proposed, characterized by including a third heat exchanger and a control module for overall control of the operation and pressure and temperature of the system.

[0021] Accordingly, the present invention can be used as a heating source that circulates high-temperature cooling water from a fuel cell through the first and second refrigerant lines to the exterior and shell of the first heat exchanger and the interior of the exterior of the third heat exchanger, thereby heating and vaporizing the inner tube of the first heat exchanger and liquid hydrogen passing through the tube.

[0022] In other words, by utilizing the waste heat of the fuel cell coolant as the energy required to vaporize liquid hydrogen, the heat generated by the fuel cell can be efficiently managed to maximize energy efficiency, and by simplifying the system configuration, the overall size (volume) and weight can be reduced and overall costs can be reduced while improving operational stability.

[0023] In addition, by utilizing the cold heat of liquid hydrogen, the heat load of the fuel cell is reduced, which reduces the energy consumption and heat transfer area for cooling the coolant, and prevents condensation and freezing that may occur in the air-cooled heat exchange method for phase-changing liquid hydrogen, and minimizes thermal management control variables, thereby increasing the operational stability of the system.

[0024] In addition, a preferred embodiment (aspect) of the present invention further comprises a heating coil that is built into the interior of the first heat exchanger and receives power from a battery to heat liquid hydrogen flowing inside the inner tube of the first heat exchanger and cooling water flowing inside the outer tube of the first heat exchanger, thereby enabling the liquid hydrogen and cooling water to be quickly heated when the temperature is low during a cold start, thereby improving vaporization.

[0025] In addition, a preferred embodiment (aspect) of the present invention further includes a preheater installed on the first hydrogen line and the second hydrogen line and configured to exchange heat between gaseous hydrogen discharged from the inner tube of the third heat exchanger and liquid hydrogen entering the inner tube of the first heat exchanger, thereby further improving thermal efficiency.

[0026] In addition, a preferred embodiment (aspect) of the present invention further includes a hydrogen supply pump installed in the middle of the first hydrogen line and forcing liquid hydrogen in the hydrogen fuel tank to the inner tube of the first heat exchanger, and a refrigerant pump installed in the middle of the second refrigerant line and for sending cooling water in the outer tube of the third heat exchanger and circulating it to the fuel cell, thereby enabling smoother and more efficient operation.

[0027] According to an embodiment that implements the technical idea on which the unique solution is based in order to solve the technical problem of the present invention, liquid hydrogen supplied to the fuel cell is heated and vaporized by using coolant that has reached a high temperature in the fuel cell and supplied to the fuel cell, and at the same time, by removing (cooling) the residual heat of the coolant using the cold heat released when the liquid hydrogen vaporizes, it is possible to change the phase of liquid hydrogen into a gaseous state without an external heat source, and also reduce the heat load of the fuel cell.

[0028] That is, by using the waste heat (residual heat) of the fuel cell coolant as the energy required to vaporize liquid hydrogen and using the cold heat released when the liquid hydrogen vaporizes as the energy required to cool the coolant, the heat generated by the fuel cell can be efficiently managed to maximize energy efficiency.

[0029] And when the temperature is low during cold start and there is not enough heating source to change the phase of liquid hydrogen, the liquid hydrogen flowing inside the inner tube of the first heat exchanger and the cooling water flowing inside the outer tube of the first heat exchanger can be quickly heated by a heating coil supplied with power from the battery, so that the liquid hydrogen can be quickly changed into phase even when the cold start temperature is low.

[0030] In addition, by utilizing the latent and sensible heat of liquid hydrogen, it is possible to directly and quickly respond to the fluctuating heat load generated in the fuel cell stack, thereby reducing the energy consumption and heat transfer area required for system operation compared to existing air-cooled or water-cooled structures, and minimizing thermal management control variables, thereby increasing the operational stability of the system.

[0031] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by a person having ordinary skill in the art to which the present invention pertains from the description of the claims.

[0032] FIG. 1 is a schematic diagram of a thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell according to an embodiment of the present invention.

[0033] FIG. 2 is a schematic diagram of a thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell according to another embodiment of the present invention.

[0034] FIG. 3 is a schematic diagram of a thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell according to another embodiment of the present invention.

[0035] FIG. 4 is a flowchart schematically illustrating a thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell according to an embodiment of the present invention.

[0036] Hereinafter, embodiments according to the present invention will be described in more detail with reference to the attached drawings.

[0037] Prior to this, it should be noted that the terms described below have been defined in consideration of their functions in the present invention, and should be interpreted as concepts that conform to the technical idea of ​​the present invention and meanings commonly used or commonly recognized in the relevant technical field.

[0038] In addition, if it is determined that a detailed description of a known function or configuration related to the present invention may obscure the gist of the present invention, the detailed description is omitted.

[0039] The drawings attached hereto may be exaggerated or simplified in some parts for the purpose of explaining the composition of the technology, the operation and working principles of the technology, convenience of understanding, and clarity of the technology, and it is disclosed that each component in the drawings does not exactly match the actual size and shape.

[0040] In addition, the term and / or in this specification means a combination of a plurality of related described items or including any item among a plurality of related described items, and when it is said that a part includes a certain component, this does not mean that other components are excluded, but rather that other components may be further included, unless specifically stated otherwise.

[0041] That is, the terms “include”, “have”, etc. used in this specification mean that a feature, number, step, process, operation, component, part, or combination thereof exists, but should be understood to not exclude the possibility of the existence or addition of one or more other features, numbers, steps, processes, operations, components, parts, or combinations thereof.

[0042] Furthermore, each process and step may occur in a different order than stated, unless the context clearly dictates otherwise. That is, each process and step may occur in the same order as stated, may be performed substantially simultaneously, or may be performed in the opposite order.

[0043] Meanwhile, the meaning of "part" and "unit" used in the present invention means a module type that performs a unit or role that processes at least one function or certain operation intended for a device or system, and this can be implemented by means such as hardware or software or a combination of hardware and software, or a device or assembly that can perform an independent operation.

[0044] And the meaning of "module" used in the present invention can mean a unit including one or a combination of two or more of hardware, software, or firmware, and can be used interchangeably with terms such as unit, logic, logical block, component, circuit, etc., and can be the minimum unit or part of an integrally configured part, can be the minimum unit or part of a part that performs one or more functions, and can be implemented mechanically or electronically.

[0045] In addition, terms such as top, bottom, upper surface, lower surface, or upper, lower, upper side, lower side, front / back, left / right, etc. used in the present invention are used for convenience to distinguish the relative positions of each component. For example, the upper side in a drawing may be named or referred to as the upper side and the lower side as the lower side, and the length direction may be named or referred to as the front / back direction, and the width direction may be named or referred to as the left / right direction.

[0046] Additionally, the terms first, second, etc. used in the present invention can be used to describe various components. That is, the terms first, second, etc. can be used only for the purpose of distinguishing one component from another.

[0047] <Specific embodiment 1>

[0048] Referring to FIGS. 1 and 2, a thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell according to an embodiment of the present invention largely includes a fuel cell (10), a hydrogen fuel tank (20), first to third heat exchangers (30), (40), (50), a control module (60), and a heating coil (70).

[0049] A fuel cell (10) receives gaseous hydrogen (GH2) and oxygen (Air) and reacts them to produce electrical energy.

[0050] Here, the fuel cell (10) may be any one of an alkaline fuel cell (AFC), a molten carbonate fuel cell (MCFC), a phosphoric acid fuel cell (PAFC), a solid oxide fuel cell (SOFC), a polymer electrolyte fuel cell (PEMFC, PEFC), and a direct methanol fuel cell (DMFC).

[0051] Meanwhile, unreacted gas discharged from the fuel cell (10) can be returned to the second hydrogen line (HL2).

[0052] The hydrogen fuel tank (20) stores liquid hydrogen (LH2) in an extremely low temperature state supplied from outside.

[0053] In addition, a sensor (not shown) that detects and measures changes in temperature and pressure inside the hydrogen fuel tank (20), converts them into signals, and transmits them to the control module (60) may be installed.

[0054] In addition, a vent pipe (not shown) may be installed in the hydrogen fuel tank (20) to facilitate air exchange by opening to the atmosphere, to facilitate the flow of liquid hydrogen, and to prevent damage due to pressure generated inside the hydrogen fuel tank (20).

[0055] And, at the end of the ventilation pipe, a safety valve (Pressure Safety Valve) can be installed to control whether to release or not to release the vaporized hydrogen gas into the atmosphere when the pressure inside the hydrogen fuel tank (20) is abnormally high.

[0056] Meanwhile, the hydrogen fuel tank (20) can be connected in a single or multiple manner in parallel or series, and the storage pressure range of the liquid hydrogen can be below the critical point.

[0057] For example, the hydrogen fuel tank (20) is configured with a vacuum multilayer insulation system of a double metal container to insulate the liquefied hydrogen, and may be a Type 1 pressure vessel made of stainless steel, high manganese steel, or aluminum steel, a Type 3 pressure vessel made by winding carbon fiber or glass fiber impregnated with resin in the circumferential and longitudinal directions on a thin metal liner such as this, or a Type 4 pressure vessel made by winding carbon fiber or glass fiber impregnated with resin in the circumferential and longitudinal directions on a liner made of a non-metallic material.

[0058] The first heat exchanger (30) is configured as a double-pipe heat exchanger to heat liquid hydrogen supplied from the hydrogen fuel tank (20) through the first hydrogen line (HL1) with the high-temperature cooling water waste heat discharged from the fuel cell (10) and supply it to the second heat exchanger (40).

[0059] That is, the first heat exchanger (30) has a double tube structure and exchanges heat in a countercurrent or countercurrent manner by means of a fluid flowing through the inner tube (31) and a fluid flowing along the annular space between the inner tube (31) and the outer tube (32).

[0060] And the inner tube (31) of the first heat exchanger (30) is connected to the tube (42) of the second heat exchanger (40) to supply liquid hydrogen (LH2) to the second heat exchanger (40), and the outer tube (32) is connected to the shell (41) of the second heat exchanger (40) to supply cooling water (CW) to the second heat exchanger (40).

[0061] That is, liquid hydrogen is supplied from a hydrogen fuel tank (20) through a first hydrogen line (HL1) inside the inner tube (31) of the first heat exchanger (30), and cooling water is supplied through a first refrigerant line (CL1) inside the outer tube (32) to reduce the heat load generated during operation of the fuel cell (10) and maintain the temperature within the normal operating range, so that heat exchange occurs through interaction.

[0062] Meanwhile, as shown in Fig. 1, an opening / closing valve (V1) may be installed along the first hydrogen line (HL1) to control the flow and amount of liquid hydrogen supplied from the hydrogen fuel tank (20) to the first heat exchanger (30).

[0063] Here, the opening / closing valve (V1) may employ a solenoid valve that switches its opening / closing operation by electromagnetic force that converts electric energy into magnetic energy according to a control signal from the control module (60).

[0064] Meanwhile, as shown in Fig. 2, a hydrogen supply pump (21) may be installed along the first hydrogen line (HL1) to supply liquid hydrogen in the hydrogen fuel tank (20) to the inner tube (31) of the first heat exchanger (30).

[0065] Accordingly, when the pressure inside the hydrogen fuel tank (20) is above a certain level, liquid hydrogen can be sent to the first heat exchanger (30) by pressure feed, and when the pressure inside the hydrogen fuel tank (20) drops below a certain level, liquid hydrogen can be supplied by the operation of the hydrogen supply pump (21).

[0066] The second heat exchanger (40) heats and vaporizes liquid hydrogen supplied from the first heat exchanger (30) using the high-temperature cooling water waste heat discharged from the fuel cell (10) and supplies it to the fuel cell (10) through the third heat exchanger (50).

[0067] And the second heat exchanger (40) supplies cooling water (CW) to the fuel cell (10) through the third heat exchanger (50) to reduce the heat load generated during operation of the fuel cell (10) and maintain the temperature within the normal operating range.

[0068] Here, the second heat exchanger (40) may be configured to have a structure in which a spiral tube (42) through which liquid hydrogen flows for heat exchange with cooling water (CW) flowing inside a cylindrical container-shaped shell (41) is built inside the shell (41).

[0069] That is, the shell (41) of the second heat exchanger (40) is connected to the outer surface (32) of the first heat exchanger (30) and the outer surface (52) of the third heat exchanger (50) by a connecting tube or the like so that cooling water (CW) can flow, and the tube (42) mounted inside the shell (41) to transfer heat is connected at both ends to the inner tube (31) of the first heat exchanger (30) and the inner tube (51) of the third heat exchanger (50) so that liquid hydrogen can flow.

[0070] Meanwhile, the second heat exchanger (40) is exemplified and described as a shell and tube type heat exchanger having a structure in which cooling water (CW) flows within a shell (41) and high-pressure liquid hydrogen (LH2) flows within a tube (42) to exchange heat, but it is not limited thereto, and it goes without saying that various types of heat exchangers, such as a plate heat exchanger, can be employed.

[0071] The third heat exchanger (50) is configured as a double-pipe heat exchanger to heat gaseous hydrogen (GH2) supplied from the second heat exchanger (40) with the high-temperature cooling water waste heat discharged from the fuel cell (10) and supply it to the fuel cell (10).

[0072] That is, the third heat exchanger (50) has a double tube structure and exchanges heat in a countercurrent or countercurrent manner by means of a fluid flowing through the inner tube (51) and a fluid flowing along the annular space between the inner tube (51) and the outer tube (52).

[0073] And the inner tube (51) of the third heat exchanger (50) is connected to the other end of the tube (42) of the second heat exchanger (40) to supply gaseous hydrogen (GH2) to the fuel cell (10), and the outer tube (52) is connected to the shell (41) of the second heat exchanger (40) to supply cooling water (CW) to the fuel cell (10).

[0074] That is, gaseous hydrogen (GH2) is supplied from the second heat exchanger (40) to the inside of the inner tube (51) of the third heat exchanger (50), and cooling water (CW) is supplied from the second heat exchanger (40) to the inside of the outer tube (52), so that heat exchange occurs through interaction.

[0075] In addition, the inner tube (51) of the third heat exchanger (50) is connected to the fuel cell (10) through a second hydrogen line (HL2) so that gaseous hydrogen (GH2) is supplied to the fuel cell (10), and the outer tube (52) is connected to the fuel cell (10) through a second refrigerant line (CL2) so that cooling water (CW) is supplied to the fuel cell (10).

[0076] That is, the second hydrogen line (HL2) connects between the fuel cell (10) and the inner tube (51) of the third heat exchanger (50).

[0077] Accordingly, the coolant (CW) discharged at a high temperature from the fuel cell (10) can be used as a heating source to heat and vaporize liquid hydrogen (LH2) passing through the inner tube (31) (51) and tube (42) by circulating through the outer shell (32) and shell (41) of the first heat exchanger (30) and the outer shell (52) of the third heat exchanger (50) through the first and second refrigerant lines (CL1) (CL2).

[0078] And, in the middle of the second hydrogen line (HL2), a T-shaped pipe is installed to branch the supply and flow direction of gaseous hydrogen (GH2), and the pipe and the hydrogen fuel tank (20) are connected to a third hydrogen line (HL3).

[0079] Additionally, a pressure control valve (V2) is installed in the middle of the third hydrogen line (HL3) to increase the supply pressure of liquid hydrogen (LH2) and the internal pressure of the hydrogen fuel tank (20).

[0080] That is, the pressure regulating valve (V2) controls the gaseous hydrogen flowing through the third hydrogen line (HL3) to be sent into the interior of the hydrogen fuel tank (20).

[0081] Here, the pressure regulating valve (V2) may employ a solenoid valve that switches its opening and closing operation by electromagnetic force that converts electric energy into magnetic energy according to the control signal of the control module (60).

[0082] Meanwhile, a refrigerant pump (53) is installed in the middle of the second refrigerant line (CL2) to circulate cooling water (CW) to the fuel cell (10).

[0083] Here, the refrigerant pump (53) is electrically connected to the control module (60) such that its power source, such as a drive motor, is operated and stopped by a control signal from the control module (60), and stably performs a pumping action at a predetermined pressure, head, and flow rate to pump the cooling water.

[0084] That is, the refrigerant pump (53) is operated by the driving force of a power source such as a driving motor, and the power source can be equipped to be started and stopped by remote control.

[0085] And, on the first and second refrigerant lines (CL1) (CL2), T-shaped tubes are installed at regular intervals to branch the flow direction of the coolant, and the tubes are connected to the third refrigerant line (CL3).

[0086] Additionally, a bypass valve (V3) is installed in the middle of the third refrigerant line (CL3) to divert a portion of the cooling water supplied to the first heat exchanger (30) to the second refrigerant line (CL2) depending on load fluctuations.

[0087]

[0088] *Here, the bypass valve (V3) may employ a solenoid valve that switches its opening and closing operation by electromagnetic force that converts electric energy into magnetic energy according to the control signal of the control module (60).

[0089] Additionally, a sensor (not shown) may be installed on the first refrigerant line (CL1) to detect and measure temperature changes in the coolant passing through it, convert it into a signal, and transmit it to the control module (60).

[0090] Meanwhile, the first to third heat exchangers (30), (40), and (50) vaporize liquefied hydrogen into vaporized hydrogen when the fuel cell (10) is in rated operation, and operation may be omitted when in the initial operation state before rated operation.

[0091] Here, the rated operating state means a state in which the fuel cell (10) reaches a preset power generation temperature and generates electric energy.

[0092] And the cooling water (CW) circulated inside the first to third heat exchangers (30)(40)(50) may be composed of at least one of chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), hydrofluorocarbon (HFC), hydrofluoroolefin (HFO), hydrocarbon, carbon dioxide, ammonia, ethylene glycol (EG) aqueous solution, and water.

[0093] The control module (60) controls the overall operation, pressure and temperature of the system.

[0094] That is, the control module (60) controls the overall operation of the heating coil (70), the driving of the refrigerant pump (53), and the opening and closing operation of the valve.

[0095] For example, when the pressure inside the hydrogen fuel tank (20) is a low pressure below a certain level, the pressure can be increased by controlling the valve to control the supply and flow of liquid hydrogen sent to the first heat exchanger (30), and when it is high pressure, the pressure and flow rate of liquid hydrogen supplied from the hydrogen fuel tank (20) to the first heat exchanger (30) can be controlled by controlling the valve.

[0096] In addition, the flow rate of cooling water flowing into the interior of the first to third heat exchangers (30)(40)(50) can be adjusted by controlling the valve according to the output and reaction heat fluctuation of the fuel cell (10) and the amount of liquid hydrogen supplied.

[0097] The heating coil (70) is supplied with power from the battery (71) and is built into the interior of the first heat exchanger (30) to heat the liquid hydrogen flowing inside the inner tube (31) of the first heat exchanger (30) and the cooling water flowing inside the outer tube (32) of the first heat exchanger (30).

[0098] Here, the battery (71) can be charged using some of the power of the fuel cell (10) to prevent discharge in normal operation mode.

[0099] <Interaction and Operation Principle>

[0100] The main functions and operating principles of the thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell according to an embodiment of the present invention configured as described above are described as follows.

[0101] First, the cooling water (CW) cooled in the first to third heat exchangers (30), (40), and (50) is circulated by the pressure of the refrigerant pump (53).

[0102] And the heat energy generated during the operation of the fuel cell (10) is recovered through heat exchange with the cooling water (CW) circulated by the pressure of the refrigerant pump (53), and in this process, the cooling water heated by the fuel cell (10) retains the residual heat inside the fuel cell (10) and returns to the first to third heat exchangers (30) (40) (50) and is cooled through heat exchange with the liquid hydrogen (LH2) flowing inside the inner tube (31) (51) and the tube (42).

[0103] At this time, liquid hydrogen (LH2) supplied from the hydrogen fuel tank (20) to the fuel cell (10) passes through the first to third heat exchangers (30), (40), and (50) and is supplied to the fuel cell (10) in a state in which the temperature is gradually increased and vaporized through heat exchange with the cooling water (CW).

[0104] That is, the heat energy generated during the operation of the fuel cell (10) is recovered through heat exchange with the cooling water (CW), and the cooling water (CW) is transported to the exterior (32) (52) and the interior of the shell (41) by the pressure of the refrigerant pump (53) in a state of absorbing the heat energy, and after heat exchange with liquid hydrogen (LH2), the temperature is lowered and continuously circulated back to the fuel cell (10) through the first and second refrigerant lines (CL1) (CL2).

[0105] And the control module (60) can control the flow rate of cooling water circulating inside the exterior (32) (52) and shell (41) according to the output (operating mode) and reaction heat fluctuation of the fuel cell (10).

[0106] That is, the control module (60) can also control the flow rate and flow of cooling water flowing into the fuel cell (10) by controlling a valve (not shown) when temperature control of the fuel cell (10) is required.

[0107] Meanwhile, the temperature of the coolant (CW) heated in the fuel cell (10) is gradually lowered as it passes through the first to third heat exchangers (30), (40), and (50), so that the cooling efficiency can be increased.

[0108] And the control module (60) controls the heating coil (70) during cold start to quickly heat the liquid hydrogen and coolant, thereby vaporizing them more quickly and better.

[0109] That is, when the system is not operated for a long time and the temperature of the coolant is low or close to room temperature, and there is insufficient heating source to change the phase of liquid hydrogen, the heating coil (70) receives power from the battery (71) and heats the liquid hydrogen flowing inside the inner tube (31) of the first heat exchanger (30) and the coolant flowing inside the outer tube (32) of the first heat exchanger (30), thereby rapidly changing the phase.

[0110] And when gaseous hydrogen (GH2) is normally supplied to the fuel cell (10) and the system operation is stabilized, the target power is produced and the temperature within the fuel cell (10) also rises. At this time, the control module (60) can stop the operation of the heating coil (70) when the coolant temperature within the second heat exchanger (40) reaches the set reference temperature.

[0111] At this time, the control module (60) can control the bypass valve (V4) installed in the middle of the third refrigerant line (CL3) according to the load change to bypass a portion of the cooling water supplied from the fuel cell (10) to the first heat exchanger (30) to the second refrigerant line (CL2).

[0112] Meanwhile, the control module (60) can control the pressure regulating valve (V2) installed in the middle of the third hydrogen line (HL3) to return some of the gaseous hydrogen coming out of the third heat exchanger (50) through the second hydrogen line (HL2) to the inside of the hydrogen fuel tank (20), and in this way, the pressure inside the hydrogen fuel tank (20) increases (Pressure Build-up), which can be used for pressure transfer (pressure feed) to send liquid hydrogen to the first heat exchanger (30) through the first hydrogen line (HL1).

[0113] <Specific embodiment 2>

[0114] Referring to FIG. 3, a thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell according to another embodiment of the present invention largely includes a fuel cell (10), a hydrogen fuel tank (20), first to third heat exchangers (30), (40), (50), a control module (60), a heating coil (70), and a preheater (80).

[0115] In particular, the preheater (80) heat-exchanges gaseous hydrogen discharged from the inner tube (51) of the third heat exchanger (50) and flowing into the second hydrogen line (HL2) with liquid hydrogen flowing into the first hydrogen line (HL1) to enter the inner tube (31) of the first heat exchanger (30) by arranging a portion of the first hydrogen line (HL1) and the second hydrogen line (HL2) adjacent to and parallel to each other.

[0116] That is, liquid hydrogen coming from the hydrogen fuel tank (20) and entering the first heat exchanger (30) can be preheated by exchanging heat with gaseous hydrogen coming from the third heat exchanger (50) while passing through the preheater (80).

[0117] In addition, a hydrogen supply pump (21) is installed in the middle of the first hydrogen line (HL1) to transfer liquid hydrogen in the hydrogen fuel tank (20) to the inner tube (31) of the first heat exchanger (30).

[0118] Accordingly, when the pressure inside the hydrogen fuel tank (20) is above a certain level, liquid hydrogen can be sent to the first heat exchanger (30) by pressure feed, and when the pressure inside the hydrogen fuel tank (20) drops below a certain level, liquid hydrogen can be supplied by the operation of the hydrogen supply pump (21).

[0119] As an example, an embodiment of a thermal management method for cold start in a thermal management system for cold start of a cryogenic fuel supply device for a fuel cell according to the present invention is as follows.

[0120] First, when the system's power switch is turned ON, a temperature check step is performed to sense the cooling water temperature inside the first heat exchanger and check the temperature value. Then, a set temperature judgment step is performed to determine whether the cooling water temperature matches the set temperature value in the temperature check step and output the signal value. At this time, if the set temperature judgment step matches the set temperature value, a signal value is output and a start mode start step is performed to execute the start mode operation.

[0121] When the startup mode is started by the above-mentioned startup mode start step, the startup mode performs a heating coil power-on step of supplying power to the heating coil, a refrigerant pump power-on step of supplying power to the refrigerant pump, and a fuel cell power supply step of supplying power to the fuel cell.

[0122] Next, a fuel cell coolant temperature check step is performed to check the coolant temperature inside the fuel cell, and a coolant set temperature determination step is performed to determine whether the coolant temperature is at the set temperature.

[0123] At this time, if the temperature value set in the cooling water set temperature determination step matches, an off step for turning off the heating coil according to the corresponding signal value and a step for turning off the start mode operation are performed so that the normal operation mode step is operated.

[0124] Here, among the components related to the thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell according to another embodiment of the present invention, components having the same or similar operational effects as the above-described embodiment use the same reference numerals, and repetitive and specific descriptions thereof are omitted.

[0125] Meanwhile, the present invention is not limited to the above-described embodiment and the attached drawings, and can be variously modified and applied in various ways not illustrated within the scope that does not depart from the technical spirit of the present invention, and it is obvious to a person having ordinary skill in the art to which the present invention pertains that it can be widely applied by replacing each component and changing it to an equivalent other embodiment.

[0126] Therefore, the contents related to modifying and applying the technical features of the present invention should be interpreted as being included within the technical idea and scope of the present invention.

Claims

1. A fuel cell (10) that produces electrical energy by reacting gaseous hydrogen and oxygen; Hydrogen fuel tank (20) for storing and supplying liquid hydrogen; A double-pipe type first heat exchanger (30) in which liquid hydrogen from the hydrogen fuel tank (20) is supplied to the inside of the inner tube (31) through the first hydrogen line (HL1), and cooling water is supplied to the inside of the outer tube (32) through the first refrigerant line (CL1) to reduce the heat load generated during operation of the fuel cell (10) and maintain the temperature within the normal operating range; A second heat exchanger (40) having a tube (42) connected at one end to the inner tube (31) of the first heat exchanger (30) and through which liquid hydrogen flows, built into a shell (41) connected to the outer surface (32) of the first heat exchanger (30) and through which cooling water flows; A double-pipe type third heat exchanger (50) in which gaseous hydrogen flowing inside an inner tube (51) connected to the other end of the tube (42) is supplied to the fuel cell (10) through a second hydrogen line (HL2), and cooling water flowing inside an outer tube (52) connected to the shell (41) of the second heat exchanger (40) is supplied to the fuel cell (10) through a second refrigerant line (CL2); and A control module (60) that controls the overall operation of the system and the pressure and temperature; A thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell, characterized by including:

2. In paragraph 1, A thermal management system for cold start of an ultra-low temperature fuel supply device for a fuel cell, characterized in that the cooling water that has reached a high temperature in the fuel cell (10) is circulated through the first refrigerant line (CL1) to the outer surface (32) of the first heat exchanger (30) and the interior of the shell (41) to heat and vaporize liquid hydrogen passing through the inner tube (31) of the first heat exchanger (30) and the tube (42).

3. In paragraph 1, A heating coil (70) built into the first heat exchanger (30) and supplied with power from a battery (71) to heat liquid hydrogen flowing inside the inner tube (31) of the first heat exchanger (30) and cooling water flowing inside the outer tube (32) of the first heat exchanger (30); A thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell, characterized in that it further includes:

4. In paragraph 1, A preheater (80) that heat-exchanges gaseous hydrogen discharged from the inner tube (51) of the third heat exchanger (50) and liquid hydrogen entering the inner tube (31) of the first heat exchanger (30) so that a portion of the first hydrogen line (HL1) and the second hydrogen line (HL2) are arranged adjacent to each other and parallel to each other; A thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell, characterized in that it further includes:

5. In any one of paragraphs 1 to 4, A hydrogen supply pump (21) installed in the middle of the first hydrogen line (HL1) and sending liquid hydrogen in the hydrogen fuel tank (20) to the inner pipe (31) of the first heat exchanger (30); and A refrigerant pump (53) installed in the middle of the second refrigerant line (CL2) and circulating the cooling water inside the outer body (52) of the third heat exchanger (50) to the fuel cell (10); A thermal management system for cold starting of a cryogenic fuel supply device for a fuel cell, characterized in that it further includes:

6. Step of turning the power switch of the system ON; Temperature check step to check the cooling water temperature inside the first heat exchanger; A set temperature judgment step that determines whether the coolant temperature is the set temperature; A start mode start step for executing a start mode operation according to the signal value output in the above set temperature judgment step; A heating coil power-on step for applying power to a heating coil by the above-mentioned startup mode starting step, a refrigerant pump power-on step for applying power to a refrigerant pump, and a fuel cell power supply step for applying power to a fuel cell; Fuel cell coolant temperature check step to check the coolant temperature inside the fuel cell; A coolant set temperature judgment step that determines whether the coolant temperature is the set temperature; An off step for turning off the heating coil according to the signal value output in the above-mentioned coolant setting temperature determination step; a step for turning off the start mode operation; is performed. To ensure that the normal operating mode steps are performed, A thermal management method for cold starting of a cryogenic fuel supply device for a fuel cell.

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