Ammonia-based power pack integrated thermal management system

Abstract

The present invention relates to an ammonia-based power pack integrated thermal management system, and disclosed herein is a liquid ammonia-based power pack integrated thermal management system capable of efficiently managing heat generated in a fuel cell, by vaporizing liquid ammonia using waste heat of fuel cell cooling water to decompose the liquid ammonia into nitrogen and hydrogen, which are then supplied to the fuel cell, and simultaneously, removing (cooling) residual heat of the fuel cell cooling water using cold energy released during the vaporization of the liquid ammonia.

Description

Ammonia-based power pack integrated thermal management system

[0001] The present invention relates to an ammonia-based power pack integrated thermal management system, and more particularly, to a liquid ammonia-based power pack integrated thermal management system capable of efficiently managing the heat generated by a fuel cell by using waste heat of a fuel cell coolant to vaporize liquid ammonia, decompose it into nitrogen and hydrogen, and supply the resulting liquid ammonia to a fuel cell, and at the same time, removing (cooling) the residual heat of the fuel cell coolant using the cold heat released when the liquid ammonia vaporizes.

[0002] Today, hydrogen fuel cells are gaining attention as an energy source with high energy efficiency and environmental friendliness 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] Recently, hydrogen fuel cell vehicles have been applying a power pack system that integrates a fuel cell stack, where the chemical reaction between hydrogen and oxygen occurs, a cooling device, a high-voltage battery, and a hydrogen tank.

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

[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, ammonia can be reformed by hydrogenation to contain nitrogen and hydrogen, and when applied to fuel cells, it does not generate any pollutants such as COx. It exists in a liquid state at -33.4℃@1 bara, making it easier to store than hydrogen. Its energy density per unit volume is about 1.7 times higher than that of liquid hydrogen, allowing for large-scale storage, giving it an advantage in terms of economic feasibility.

[0012] Typically, the process for producing high-purity hydrogen from ammonia involves three steps. Ammonia is decomposed into nitrogen and hydrogen at high temperatures via a catalyst. Residual (unreacted) ammonia is removed at room temperature. Then, hydrogen is separated through a room-temperature PSA (pressure swing adsorption) process, producing high-purity hydrogen with a purity of 99.97% or higher.

[0013] Here, the reaction of decomposing ammonia into nitrogen and hydrogen proceeds by absorbing heat from the surroundings during the reaction process through an endothermic reaction such as catalytic decomposition, so a high supply of reaction heat is required, and a catalyst is used to increase the efficiency of the decomposition reaction.

[0014] That is, the hydrogen extraction catalytic reaction based on thermochemical decomposition of ammonia is 2NH3→ N2+ 3H2, ΔH = 46.22 kJ / mol of NH3, and the equilibrium conversion rate increases as the reaction temperature increases, and has an equilibrium conversion rate of more than 99% at 400℃ or higher under atmospheric pressure conditions.

[0015] Meanwhile, in the case of hydrogen fuel cell vehicles, the efficiency of the entire system can be improved by applying an integrated thermal management system that includes heat removal and cooling methods for the fuel cell stack.

[0016] 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.

[0017] The background technology or prior art described herein is information that the inventor possesses or acquired in the process of deriving and completing the present invention, and is only stated to be helpful in understanding the technical significance of the present invention and useful in prior art research and examination, and does not mean technology that is generally known and widely used in the technical field to which the present invention belongs prior to the application for the present invention.

[0018] [Prior Art Literature]

[0019] [Patent Document]

[0020] (Patent Document 1) KR 10-2522896 B1 2023. 04. 13.

[0021] (Patent Document 2) KR 10-2567867 B1 2023. 08. 11.

[0022] Accordingly, the inventor of the present invention has comprehensively considered all the above-mentioned matters and, at the same time, has made great efforts to develop a novel ammonia-based power pack integrated thermal management system that utilizes the heat load absorbed by the coolant from the fuel cell stack as energy required to vaporize liquid ammonia in order to maintain the fuel cell at a normal operating temperature range, and simultaneously utilizes the cold heat released when the liquid ammonia vaporizes as energy required to cool the coolant, thereby efficiently managing the heat generated by the fuel cell and maximizing energy efficiency. In addition, by recovering unreacted hydrogen and nitrogen discharged from the fuel cell to the reactor and using them as fuel for the reactor that decomposes ammonia, the efficiency of ammonia decomposition can be increased, and in addition, by simplifying the configuration of the power pack system, the stability of operation can be improved. As a result of this, the inventor of the present invention has made continuous research and has devoting great efforts to developing a novel ammonia-based power pack integrated thermal management system.

[0023] Therefore, the technical problem and purpose to be solved by the present invention is to provide an integrated thermal management system for an ammonia-based power pack that can maximize energy efficiency by utilizing the heat load of fuel cell coolant and the cold heat of liquid ammonia as energy required for vaporization and cooling.

[0024] Another technical problem and object of the present invention is to provide an integrated thermal management system for an ammonia-based power pack that can improve the thermal decomposition efficiency of ammonia by recovering and combusting unreacted gas (a mixture of hydrogen and nitrogen) of a fuel cell.

[0025] 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.

[0026] In order to effectively achieve a specific technical objective 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 for producing electrical energy by receiving oxygen together with at least one gas among hydrogen or a mixture of hydrogen and nitrogen and reacting them, a fuel tank for storing and supplying liquid ammonia, a heat exchanger for supplying cooling water to the fuel cell through a first refrigerant line to reduce the heat load generated during the operation of the fuel cell and maintain the temperature within a normal operating range, receiving the cooling water that has reached a high temperature in the fuel cell through a second refrigerant line, heating and vaporizing the liquid ammonia supplied from the fuel tank through the first fuel line, and discharging it through a second fuel line, a combustion device for receiving gaseous ammonia discharged from the heat exchanger through the second fuel line, and combusting at least one of unreacted hydrogen or a mixture of hydrogen and nitrogen supplied from the fuel cell through a gas recovery line in a combustion chamber, wherein The present invention proposes an integrated thermal management system for an ammonia-based power pack, characterized by employing a reactor that transfers heat generated by combustion to the thermal decomposition chamber, decomposes it into nitrogen and hydrogen through an endothermic reaction, and discharges it together with unreacted ammonia gas, a gas purification unit that separates and removes at least one of nitrogen and ammonia gas from the reaction product discharged from the reactor and supplies it to the fuel cell through a third fuel line, and a control module that controls the overall operation, pressure, and temperature of the system.

[0027] Accordingly, the present invention can utilize the high-temperature coolant from the fuel cell as a heating source to circulate the coolant inside the shell through the second coolant line and heat and vaporize liquid ammonia passing through the heat transfer tube. In other words, by utilizing the waste heat of the fuel cell coolant as the energy required to vaporize liquid ammonia, the heat generated by the fuel cell can be efficiently managed to maximize energy efficiency, and in addition, the configuration of the power pack system can be simplified to reduce the overall size (volume) and weight as well as the stability of operation, and to save on overall costs.

[0028] In addition, by utilizing the cold heat of liquid ammonia, the heat load of the fuel cell is reduced, thereby reducing the energy consumption and heat transfer area for cooling the coolant, and preventing condensation and freezing that may occur in the air-cooled heat exchange method for phase changing liquid hydrogen, as well as minimizing thermal management control variables, thereby increasing the operational stability of the system.

[0029] In particular, the reactor uses the heat generated by combustion of unreacted hydrogen supplied from a fuel cell or a mixture of hydrogen and nitrogen gas and a catalyst charged in the thermal decomposition chamber to catalytically decompose gaseous ammonia supplied from a heat exchanger in the thermal decomposition chamber, thereby discharging a mixture of nitrogen, hydrogen, and residual (unreacted) ammonia gas, thereby improving ammonia decomposition efficiency.

[0030] In addition, as a preferred embodiment of the present invention, the reactor further comprises an electric heater for increasing the initial heating temperature of the combustion chamber, so that when the temperature of the combustion chamber is not sufficient to combust hydrogen, the electric heater can rapidly increase the temperature of the combustion chamber to create an atmosphere and temperature at which hydrogen can be quickly combusted.

[0031] In addition, a preferred embodiment (aspect) of the present invention comprises: a refrigerant pump installed in the middle of the first refrigerant line and circulating the cooling water inside the shell to the fuel cell, a first sensor that detects and measures a change in temperature of the cooling water passing through the second refrigerant line and converts it into a signal and transmits it to the control module, a third refrigerant line connecting between the first refrigerant line and the second refrigerant line, a bypass valve installed in the middle of the third refrigerant line and controls the flow rate of the cooling water circulating inside the shell through the second refrigerant line according to the change in output and reaction heat of the fuel cell, a second sensor that detects and measures a change in temperature and pressure inside the fuel tank and converts it into a signal and transmits it to the control module, a fuel pump installed in the middle of the first fuel line and circulating the liquid ammonia inside the fuel tank to the heat exchanger, and a fuel pump installed in the middle of the third fuel line and compresses at least one of nitrogen and hydrogen gas passing through the gas purification unit and transmits it to the fuel cell. It may further comprise a compressor for transmitting air and a blower for supplying air to the fuel cell and the reactor.

[0032] In addition, a preferred embodiment of the present invention may further include a fourth fuel line connecting the fuel tank and the middle of the first fuel line, a regulator installed in the middle of the fourth fuel line and controlling gaseous ammonia in the fuel tank to be supplied to the heat exchanger through the first fuel line when the pressure in the fuel tank is above a certain range, a first on-off valve installed in the middle of the first fuel line and controlling the flow rate and the flow of liquid ammonia supplied from the fuel tank to the heat exchanger, and a first check valve installed in the middle of the first fuel line and automatically restricting the flow of liquid ammonia to prevent backflow.

[0033] In addition, a preferred embodiment (aspect) of the present invention may further include a fifth fuel line connecting the fuel tank and the middle of the second fuel line, and a pressure regulating valve installed in the middle of the fifth fuel line and controlling gaseous ammonia flowing through the fifth fuel line to be sent into the interior of the fuel tank in order to increase the supply pressure of liquid ammonia and the internal pressure of the fuel tank.

[0034] In addition, a preferred embodiment (aspect) of the present invention may further include a fourth refrigerant line connected to the second refrigerant line and allowing the cooling water flowing in the second refrigerant line to flow in a bypass manner, a radiator installed in the middle of the fourth refrigerant line and dissipating the heat of the cooling water into the atmosphere, and a second opening / closing valve installed in the middle of the fourth refrigerant line and controlling the flow rate and amount of cooling water supplied from the fuel cell to the radiator.

[0035] In addition, a preferred embodiment (aspect) of the present invention further comprises a preheater installed on the first fuel line and recovering heat from a reaction product discharged from the fuel cell and exchanging heat with liquid ammonia entering the heat exchanger, thereby enabling the high-temperature gas decomposed through the catalytic reaction to be heat-exchanged and reused to preheat liquid ammonia, thereby improving the decomposition efficiency.

[0036] In addition, a preferred embodiment (aspect) of the present invention further comprises a first three-way valve installed in the middle of the third fuel line and changing and controlling the flow direction of gas, a second three-way valve installed in the middle of the gas recovery line and changing and controlling the flow direction of gas, and a direction change pipe connecting the first three-way valve and the second three-way valve, so that by controlling the first three-way valve and the second three-way valve, at least one gas among hydrogen or a mixed gas of hydrogen and nitrogen that has passed through the gas purification unit is directly supplied to the reactor through the direction change pipe without passing through the fuel cell, thereby controlling the reaction temperature within the reactor without consuming fuel in the fuel cell.

[0037] 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 ammonia supplied to the fuel cell is heated and vaporized by using high-temperature coolant in the fuel cell, decomposed into nitrogen and hydrogen, and then supplied to the fuel cell, and at the same time, by removing (cooling) the residual heat of the fuel cell coolant using the cold heat released when the liquid ammonia vaporizes, it is possible to change the phase of liquid ammonia into a gaseous state without an external heat source, and also reduce the heat load of the fuel cell.

[0038] That is, by using the waste heat (residual heat) of the fuel cell coolant as the energy required to vaporize liquid ammonia and the cold heat released when liquid ammonia vaporizes as the energy required to cool the coolant, the heat generated by the fuel cell can be efficiently managed to maximize energy efficiency.

[0039] In addition, by recovering unreacted hydrogen or a mixture of hydrogen and nitrogen emitted from the fuel cell among the generated gases obtained by endothermic reaction of ammonia and burning them to use as a heat source, the efficiency of ammonia decomposition can be increased as well as stability in case of sudden electrical loads.

[0040] In addition, by utilizing the latent and sensible heat of liquid ammonia, 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.

[0041] In addition, since there is no need for separate equipment such as indirect thermal management systems, the configuration of the power pack system can be simplified, which not only improves operational stability but also reduces the overall size (volume) and weight, and reduces overall costs.

[0042] 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.

[0043] FIG. 1 is a schematic diagram of an ammonia-based power pack integrated thermal management system according to an embodiment of the present invention.

[0044] FIG. 2 is a schematic diagram of an ammonia-based power pack integrated thermal management system according to another embodiment of the present invention.

[0045] FIG. 3 is a schematic diagram of an ammonia-based power pack integrated thermal management system according to another embodiment of the present invention.

[0046] FIG. 4 is a schematic diagram of an ammonia-based power pack integrated thermal management system according to another embodiment of the present invention.

[0047] Hereinafter, embodiments according to the present invention will be described in more detail with reference to the attached drawings.

[0048] 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 consistent with the technical idea of ​​the present invention and meanings commonly used or commonly recognized in the relevant technical field.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] <Specific embodiment 1>

[0057] Referring to FIG. 1, an ammonia-based power pack integrated thermal management system according to an embodiment of the present invention largely includes a fuel cell (10), a fuel tank (20), a heat exchanger (30), a reactor (40), a gas purification unit (50), and a control module (60).

[0058] A fuel cell (10) produces electrical energy by simultaneously supplying and reacting at least one gas, either hydrogen (H2) or a mixture of hydrogen and nitrogen (N2), with oxygen (Air).

[0059] Here, the fuel cell (10) may be, for example, 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).

[0060] Meanwhile, unreacted hydrogen or hydrogen and nitrogen mixed gas discharged from the fuel cell (10) is supplied to the reactor (40) through the gas recovery line (GL).

[0061] The fuel tank (20) stores low-temperature liquid ammonia (LNH3) supplied from outside.

[0062] And, a second sensor (54) is installed in the fuel tank (20) to detect and measure changes in temperature and pressure inside the tank, convert them into signals, and transmit them to the control module (60).

[0063] Additionally, the fuel tank (20) is connected to the heat exchanger (30) and the first fuel line (AL1).

[0064] And, in the middle of the first fuel line (AL1), a fuel pump (55) is installed to transfer liquid ammonia in the fuel tank (20) to the heat exchanger (30).

[0065] Additionally, a vent pipe (61) is installed in the fuel tank (20) to open to the atmosphere.

[0066] And in the middle of the ventilation pipe (61), a safety valve (Pressure Safety Valve) is installed to control whether or not the gaseous ammonia (GNH3) in the fuel tank (20) is released into the atmosphere.

[0067] That is, the safety valve prevents damage to the fuel tank (20) due to pressure by releasing the gaseous ammonia vaporized in the fuel tank (20) into the atmosphere through the vent pipe (61) when the pressure is abnormally high.

[0068] Here, the safety valve may be configured to, for example, have a structure in which, when the maximum charging pressure of the fuel tank (20) is 2000 kPa and the pressure inside the fuel tank (20) exceeds 2000 kPa, the switch operates to open the valve, thereby releasing gaseous ammonia into the atmosphere.

[0069] And, an injection pipe (71) for injecting liquid ammonia into the fuel tank (20) is installed.

[0070] Additionally, a second check valve (72) is installed in the middle of the injection pipe (71) to automatically limit the flow of liquid ammonia and prevent backflow.

[0071] Meanwhile, the fuel tanks (20) can be connected in a single or multiple manner in parallel or series, and the storage pressure range of the liquid ammonia can be below the critical point.

[0072] Here, the fuel tank (20) is configured with a vacuum multilayer insulation system of a double metal container, for example, to insulate the liquefied ammonia, 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, 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.

[0073] The heat exchanger (30) heats and vaporizes liquid ammonia supplied from the fuel tank (20) through the first fuel line (AL1) and supplies it to the fuel cell (10) through the second fuel line (AL2).

[0074] And the heat exchanger (30) supplies cooling water (CW) to the fuel cell (10) 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.

[0075] Here, the heat exchanger (30) is structured to have a spiral heat transfer tube (32) built in, through which liquid ammonia flows for heat exchange with cooling water flowing inside a cylindrical container-shaped shell (31).

[0076] And the shell (31) is connected to the fuel cell (10) and the second refrigerant line (CL2), and both ends of the heat transfer tube (32) are connected to the first and second fuel lines (AL1) (AL2).

[0077] That is, the second fuel line (AL2) connects between the fuel cell (10) and the heat transfer tube (32) of the heat exchanger (30).

[0078] Accordingly, the coolant that has reached a high temperature in the fuel cell (10) can be circulated into the interior of the shell (31) through the second coolant line (CL2) to be used as a heating source to heat and vaporize liquid ammonia passing through the heat transfer tube (32).

[0079] A refrigerant pump (51) is installed in the middle of the first refrigerant line (CL1) to circulate the coolant inside the shell (31) through the fuel cell (10) to the shell (31).

[0080] The refrigerant pump (51) is electrically connected to the control module (60) such that its driving motor, which is its power source, is operated and stopped by a control signal from the control module (60), and can stably perform a pumping action at a predetermined pressure, head, and flow rate to pump the cooling water.

[0081] Here, the refrigerant pump (51) is driven by the driving force of a power source such as a drive motor, and the power source can be equipped to be started and stopped by remote control.

[0082] In addition, a first sensor (52) is installed on the second refrigerant line (CL2) to detect and measure the temperature change of the coolant passing through the second refrigerant line (CL2), convert it into a signal, and transmit it to the control module (60).

[0083] The first refrigerant line (CL1) and the second refrigerant line (CL2) are connected by a third refrigerant line (CL3).

[0084] In the middle of the third refrigerant line (CL3), a bypass valve (53) is installed to control the flow rate of coolant circulating into the interior of the shell (31) through the second refrigerant line (CL2) according to the output and reaction heat fluctuations of the fuel cell (10).

[0085] That is, the bypass valve (53) is installed in the middle of the third refrigerant line (CL3) connecting the first refrigerant line (CL1) and the second refrigerant line (CL2) to bypass the coolant according to the output and reaction heat fluctuation of the fuel cell (11).

[0086] Here, the bypass valve (53) may employ a solenoid valve that switches its opening and closing operation by electromagnetic force that converts electric energy into magnetic energy according to a control signal from the control module (60).

[0087] A T-shaped pipe is installed in the middle of the first fuel line (AL1) to connect to the fourth fuel line (AL4), and a first check valve (66) is installed in the middle of the first fuel line (AL1) between the pipe and the fuel tank (20) to automatically limit the flow of liquid ammonia and prevent reverse flow.

[0088] And, in the middle of the first fuel line (AL1), a first opening / closing valve (65) is installed to control the flow and amount of liquid ammonia supplied from the fuel tank (20) to the heat exchanger (30).

[0089] Here, the first opening / closing valve (65) 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).

[0090] The fourth fuel line (AL4) connects the fuel tank (20) and the middle of the first fuel line (AL1).

[0091] And, in the middle of the fourth fuel line (AL4), a regulator (64) is installed to automatically adjust the supply of gaseous ammonia in the form of evaporated gas to the heat exchanger (30) through the first fuel line (AL1) when the pressure inside the fuel tank (20) is above a certain range.

[0092] That is, since the third fuel line (AL3) between the fuel tank (20) and the regulator (64) is always under pressure, when the first pressure is reached, the regulator (64) opens, and when the pressure rises rapidly and reaches the second pressure, which is higher than the first pressure, the safety valve opens.

[0093] And on the second refrigerant line (CL2), T-shaped pipes are installed at regular intervals to branch the flow direction of the coolant.

[0094] The fourth refrigerant line (CL4) is connected to the second refrigerant line (CL2) so that the cooling water flowing in the second refrigerant line (CL2) flows in a bypass manner.

[0095] And, a radiator (83) that dissipates the heat of the coolant into the atmosphere is installed in the middle of the fourth refrigerant line (CL4).

[0096] Here, the radiator (83) may be formed in a fin tube manner to increase the heat transfer area for heat exchange, surface area and efficiency, or may include cooling fins or cooling plates.

[0097] Additionally, a second opening / closing valve (84) is installed in the middle of the fourth refrigerant line (CL4) to control the flow and amount of coolant supplied from the fuel cell (10) to the radiator (83).

[0098] Here, the second opening / closing valve (84) 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).

[0099] Meanwhile, the heat exchanger (30) vaporizes liquefied hydrogen into vaporized hydrogen when the fuel cell (10) is in rated operation, and its operation can be omitted when in the initial operation state before rated operation.

[0100] Here, the rated operating state means a state in which the fuel cell (10) reaches a preset power generation temperature and generates electric energy.

[0101] Meanwhile, the heat exchanger (30) is exemplified and described as a shell and tube type heat exchanger having a structure in which cooling water (CW) flows within a shell (31) and high-pressure liquid ammonia flows within a heat transfer tube (32) to exchange heat, but it is not limited thereto, and it is of course possible to employ various types of heat exchangers such as a plate heat exchanger.

[0102] In addition, the cooling water (CW) circulated inside the heat exchanger (30) may be made of at least one of, for example, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), hydrofluoroolefins (HFOs), hydrocarbons, carbon dioxide, ammonia, an aqueous solution of ethylene glycol (EG), and water.

[0103] The reactor (40) decomposes gaseous ammonia (GNH3) discharged from the heat exchanger (30) through the second fuel line (AL2) through an endothermic reaction and discharges a mixed gas of nitrogen (N2), hydrogen (H2), and residual (unreacted) ammonia.

[0104] And the reactor (40) includes a thermal decomposition chamber (41) that is charged with a catalyst and supplies gaseous ammonia discharged from a heat exchanger (30) through a second fuel line (AL2), and a combustion device (42) that supplies unreacted hydrogen or a mixture of hydrogen and nitrogen gas from a fuel cell (10) through a gas recovery line (GL), supplies air through a blower (57), and combusts it in a combustion chamber (43).

[0105] That is, the reactor (40) uses the high temperature heat emitted by the combustion of unreacted hydrogen or a mixture of hydrogen and nitrogen supplied from the fuel cell (10) through the gas recovery line (GL) and air supplied through the blower (57) to catalytically decompose gaseous ammonia supplied from the heat exchanger (30) in a thermal decomposition chamber (41) to discharge a mixture of nitrogen, hydrogen, and residual (unreacted) ammonia gas.

[0106] At this time, the exhaust gas generated in the combustion chamber (43) transfers high-temperature heat during the exhaust process, thereby promoting the catalytic reaction in the thermal decomposition chamber (41).

[0107] Here, the type or structural form of the combustion device (42) is not particularly limited, but preferably, a combination of a burner and a ventilator can be employed to generate combustion gas by injecting heat in the form of a flame through combustion.

[0108] In addition, the combustion device (42) can have its injection port positioned vertically downward or horizontally so that combustion gas can easily flow into the combustion chamber (43).

[0109] In addition, the combustion device (42) may employ a combination of devices necessary for combustion, such as a burner, a fuel supply pipe, a fuel shut-off valve, a ventilation device, a ventilation control device, an air resister, an injection pump, a heating device, and a safety device.

[0110] And the reactor (40) can be connected to a T-shaped pipe installed in the middle of the second fuel line (AL2) to branch the supply and flow direction of gaseous ammonia (GNH3).

[0111] Here, the reactor (40) can adopt a structure that decomposes ammonia into nitrogen and hydrogen through an endothermic reaction using a thermochemical decomposition-based hydrogen extraction catalyst.

[0112] For example, a single bed system can be applied that exhibits an ammonia conversion rate of 99.5% or more at a furnace temperature in the range of 400 to 600°C using a ruthenium-based precious metal catalyst.

[0113] In addition, the reactor (40) may be structured so that ammonia supplied between the catalysts coated on the outside of the tubes or filled in the shell in a shell-and-tube type thermal decomposition chamber (41) is decomposed into hydrogen and nitrogen as it passes through the catalyst layer, and the decomposed products are discharged to the outside of the thermal decomposition chamber (41).

[0114] In addition, as an ammonia decomposition catalyst that converts ammonia into nitrogen and hydrogen, a structure in which a catalytically active ingredient such as ruthenium (Ru) is supported on a composite oxide solid solution support composed of lanthanum oxide and cerium oxide or a sponge-shaped support made of a metal material with good heat transfer effect can be adopted.

[0115] And, an electric heater (44) is installed inside the reactor (40) to increase the initial heating temperature.

[0116] That is, the electric heater (44) is built into the reactor (40) to automatically rapidly increase the temperature by receiving power from the battery (45) when the internal temperature of the reactor (40) does not reach the preset combustible temperature of hydrogen.

[0117] Here, the battery (45) can be charged using some of the power of the fuel cell (10) to prevent discharge in normal operation mode.

[0118] Meanwhile, a blower (57) is provided to stably supply air to the fuel cell (10) and reactor (40).

[0119] Here, a Sirocco fan or ring blower can be adopted and applied as a blower (57).

[0120] The gas purification unit (50) is connected to the reactor (40) and the fuel cell (10) via a third fuel line (AL3) to separate and remove at least one of nitrogen and ammonia from the reaction product discharged from the reactor (40).

[0121] And, in the middle of the third fuel line (AL3), a compressor (56) may be installed to increase the pressure of at least one of the hydrogen or the mixed gas of hydrogen and nitrogen that has passed through the gas purification unit (50) to the inlet pressure of the fuel cell (10) and send it to the fuel cell (10).

[0122] Here, the gas purification unit (50) can perform adsorption, depressurization, and desorption in a cross-sectional manner or charge an adsorbent to adsorb and remove nitrogen and ammonia among the reaction products.

[0123] In addition, as an adsorbent, one or more aluminosilicates selected from among A type, X type, Y type, ZSM-5, and L type that selectively adsorb nitrogen under constant pressure conditions, and on which one or more metal ions selected from among hydrogen ions, calcium ions, sodium ions, and potassium ions are supported can be used.

[0124] Meanwhile, the gas purification unit (50) can be formed by combining a pressure swing adsorption vessel (PSA) or membrane filter that filters out impurities of hydrogen decomposed in the reactor (40), and an adsorber that separates, purifies, and removes ammonia using the adsorption phenomenon.

[0125] The control module (60) controls the overall operation, pressure and temperature of the system.

[0126] That is, the control module (60) controls the overall operation of various pumps and the opening and closing operation of valves.

[0127] For example, when the output of the fuel cell (10) suddenly increases or decreases, the first opening / closing valve (65) can be controlled to change the supply and flow of liquid ammonia sent to the heat exchanger (30).

[0128] And, by controlling the bypass valve (53) installed in the middle of the third refrigerant line (CL3) according to the output and reaction heat fluctuation of the fuel cell (10) and the amount of liquid ammonia supplied, the flow rate of the cooling water flowing into the inside of the shell (31) through the second refrigerant line (CL2) can be adjusted, thereby increasing or decreasing the amount of energy supplied required for vaporizing the liquid ammonia.

[0129] In addition, the control module (60) can operate the combustion device (42) and electric heater (44) installed inside the reactor (40) using power from the battery (43).

[0130] <Interaction and Operation Principle>

[0131] The main functions and operating principles of the ammonia-based power pack integrated thermal management system according to the embodiment of the present invention configured as described above are described as follows.

[0132] First, the cooling water cooled in the heat exchanger (30) is circulated by the pressure of the refrigerant pump (51).

[0133] And the heat energy generated during the operation of the fuel cell (10) is recovered through heat exchange with the cooling water circulated by the pressure of the refrigerant pump (51), and in this process, the cooling water heated inside the fuel cell (10) retains the residual heat inside the fuel cell (10) and returns to the heat exchanger (30) and is cooled through heat exchange with the liquid ammonia flowing inside the heat transfer tube (32).

[0134] At this time, the liquid ammonia supplied from the fuel tank (20) to the fuel cell (10) is supplied to the reactor (40) in a vaporized state through heat exchange with the cooling water while passing through the heat exchanger (30), and the gaseous ammonia introduced into the reactor (40) is thermally decomposed into nitrogen and hydrogen through an endothermic reaction by the combustion heat and the catalyst and is discharged together with unreacted ammonia gas.

[0135] That is, the reactor (40) uses the heat generated by combustion of unreacted hydrogen or nitrogen supplied from the fuel cell (10) through the gas recovery line (GL) and the catalyst charged in the thermal decomposition chamber (41) to catalytically decompose gaseous ammonia supplied from the heat exchanger (30) within the thermal decomposition chamber (41) to discharge a mixed gas of nitrogen, hydrogen, and unreacted ammonia as products.

[0136] In addition, nitrogen and ammonia gas among the reaction products discharged from the reactor (40) are removed by adsorption while passing through the gas purification unit (50), and high-purity hydrogen is supplied to the fuel cell (10).

[0137] That is, the heat energy generated during the operation of the fuel cell (10) is recovered through heat exchange with the cooling water, and the cooling water, in a state in which the heat energy has been absorbed, is transferred to the shell (31) through the second refrigerant line (CL2) by the pressure of the refrigerant pump (51), and after heat exchange with the liquid ammonia in the heat transfer tube (32), the temperature is lowered and continuously circulated back to the fuel cell (10) through the first refrigerant line (CL1).

[0138] And the control module (60) can control the flow rate of coolant circulating into the interior of the shell (31) through the second coolant line (CL2) according to the output (operating mode) and reaction heat fluctuation of the fuel cell (10).

[0139] That is, the control module (60) can control the bypass valve (53) to control the flow rate and amount of cooling water flowing into the fuel cell (10) when temperature control of the fuel cell (10) is required.

[0140] At this time, the control module (60) can increase the cooling efficiency by adjusting the temperature of the coolant heated in the fuel cell (10) to be lowered further as it passes through the fourth coolant line (CL4) to the radiator (83).

[0141] That is, the control module (60) can control the second opening / closing valve (84) to control the flow rate and flow of the cooling water supplied from the fuel cell (10) to the heat exchanger (30) when rapid temperature control of the cooling water is required.

[0142] And when the pressure inside the fuel tank (20) is above a certain range, the regulator (64) can automatically adjust so that the gaseous ammonia discharged through the vent pipe (61) is preferentially supplied to the fuel cell (10) through the heat exchanger (30).

[0143] At this time, the control module (60) can control the supply amount of ammonia supplied from the fuel tank (20) to the heat exchanger (30) by controlling the first opening / closing valve (65) installed in the middle of the first fuel line (HL1).

[0144] Meanwhile, when the internal pressure of the fuel tank (20) is higher than the set value of the regulator (64), the regulator (64) is opened and high-pressure gas is supplied to the heat exchanger (30) through the fourth fuel line (AL4), and at the same time, the control module (60) automatically stops the operation of the fuel pump (55).

[0145] <Specific embodiment 2>

[0146] Referring to FIG. 2, an ammonia-based power pack integrated thermal management system according to another embodiment of the present invention includes a fuel cell (10), a fuel tank (20), a heat exchanger (30), a reactor (40), a gas purification unit (50), and a control module (60).

[0147] And, in the middle of the second fuel line (AL2) connecting the fuel cell (10) and the heat transfer tube (32) of the heat exchanger (30), a T-shaped tube is installed to branch the supply and flow direction of gaseous ammonia.

[0148] Additionally, the fuel tank (20) and the middle (T-shaped tube) of the second fuel line (AL2) are connected to the fifth fuel line (AL5).

[0149] And, in the middle of the fifth fuel line (AL5), a pressure regulating valve (74) is installed to increase the supply pressure of liquid ammonia and the internal pressure of the fuel tank (20).

[0150] That is, the pressure regulating valve (74) controls the gaseous ammonia flowing through the fifth fuel line (AL5) to be sent into the interior of the fuel tank (20).

[0151] Accordingly, when the pressure inside the fuel tank (20) is below a certain level, the control module (60) controls the pressure regulating valve (74) installed in the middle of the fifth fuel line (HL5) to return some of the gaseous ammonia coming out of the heat exchanger (30) through the second fuel line (HL2) to the inside of the fuel tank (20), and in this way, the pressure inside the fuel tank (20) rises above a certain level, which can be used for pressure feed to send liquid ammonia to the heat exchanger (30) through the first fuel line (HL1).

[0152] Among the components related to the ammonia-based power pack integrated thermal management system 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.

[0153] <Specific embodiment 3>

[0154] Referring to FIG. 3, an ammonia-based power pack integrated thermal management system according to another embodiment of the present invention largely includes a fuel cell (10), a fuel tank (20), a heat exchanger (30), a reactor (40), a gas purification unit (50), a control module (60), and a preheater (90).

[0155] In particular, a preheater (90) is installed on the first fuel line (HL1) to recover heat from the reaction product discharged from the reactor (40) and to heat-exchange liquid ammonia to be introduced into the heat exchanger (30).

[0156] That is, the preheater (90) is directly connected to the first fuel line (HL1) and is connected to the air duct between the reactor (40) and the gas purification unit (50).

[0157] Accordingly, liquid ammonia that comes out of the fuel tank (10) and enters the heat exchanger (30) can improve vaporization efficiency by preheating it through heat exchange with the high-temperature gas decomposed through a catalytic reaction while passing through the preheater (90).

[0158] Among the components related to the ammonia-based power pack integrated thermal management system 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.

[0159] <Specific embodiment 4>

[0160] Referring to FIG. 4, an ammonia-based power pack integrated thermal management system according to another embodiment of the present invention largely includes a fuel cell (10), a fuel tank (20), a heat exchanger (30), a reactor (40), a gas purification unit (50), a control module (60), and a preheater (90).

[0161] And, in the middle of the third fuel line (AL3) connecting the fuel cell (10) and the gas purification unit (50), a first three-way valve (86) is installed to change and control the flow direction of gas.

[0162] Additionally, a second three-way valve (87) is installed in the middle of the gas recovery line (GL) connecting the fuel cell (10) and the reactor (40) to change and control the flow direction of the gas.

[0163] In addition, a direction change pipe (88) is connected between the first three-way valve (86) and the second three-way valve (87).

[0164] Here, the first three-way valve (86) and the second three-way valve (87) each have an inlet in one direction and an outlet in two and three directions, so that in normal times, they are opened in the direction communicating with the fuel cell (10) and closed in the direction communicating with the gas recovery line (GL), allowing gas to flow selectively.

[0165] Therefore, by controlling the first three-way valve (86) and the second three-way valve (87), at least one of hydrogen or a mixture of hydrogen and nitrogen that has passed through the gas purification unit (50) is directly supplied to the reactor (40) through the diverter pipe (88), thereby rapidly increasing the reaction temperature within the reactor (40).

[0166]

[0167] *Here, among the components related to the ammonia-based power pack integrated thermal management system 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.

[0168] 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.

[0169] 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 supplying oxygen and reacting at least one of hydrogen or a mixture of hydrogen and nitrogen; Fuel tank (20) for storing and supplying liquid ammonia; A heat exchanger (30) that supplies cooling water to the fuel cell (10) through the first cooling water line (CL1) to reduce the heat load generated during the operation of the fuel cell (10) and maintain the temperature within the normal operating range, and receives cooling water that has reached a high temperature in the fuel cell (10) through the second cooling water line (CL2), heats and vaporizes liquid ammonia supplied from the fuel tank (20) through the first fuel line (AL1), and discharges it through the second fuel line (AL2); A combustion device (42) that receives gaseous ammonia discharged from the heat exchanger (30) through the second fuel line (AL2) and combusts at least one of unreacted hydrogen or a hydrogen and nitrogen mixed gas supplied from the fuel cell (10) through the gas recovery line (GL) and a thermal decomposition chamber (41) charged with a catalyst within a combustion chamber (43), wherein the reactor (40) transfers the heat generated by the combustion to the thermal decomposition chamber (41) and decomposes it into nitrogen and hydrogen through an endothermic reaction; A gas purification unit (50) that separates and removes at least one of nitrogen and residual (unreacted) ammonia from the reaction product discharged from the reactor (40) and supplies the separated product to the fuel cell (10) through the third fuel line (AL3); and A control module (60) that controls the overall operation of the system and the pressure and temperature; Including, The above reactor (40) is characterized in that it uses the heat generated by combustion of unreacted hydrogen or a mixture of hydrogen and nitrogen supplied from the fuel cell (10) through the gas recovery line (GL) and the catalyst charged in the thermal decomposition chamber (41) to catalytically decompose gaseous ammonia supplied from the heat exchanger (30) within the thermal decomposition chamber (41) to discharge a mixture of nitrogen, hydrogen, and residual (unreacted) ammonia.

2. In paragraph 1, An ammonia-based power pack integrated thermal management system, characterized in that the above reactor (40) further includes an electric heater (44) that increases the temperature of the thermal decomposition chamber (41).

3. In paragraph 1, The heat exchanger (30) is characterized in that a shell (31) storing coolant is connected to the fuel cell (10) through a second coolant line (CL2), a spiral heat transfer tube (32) is built into the shell (31) whose both ends are connected to the first and second fuel lines (AL1) (AL2), and the coolant that has reached a high temperature in the fuel cell (10) is circulated into the interior of the shell (31) through the second coolant line (CL2) to heat and vaporize liquid ammonia passing through the heat transfer tube (32) and is used as a heating source.

4. In paragraph 1, A refrigerant pump (51) installed in the middle of the first refrigerant line (CL1) and circulating the cooling water within the shell (31) to the fuel cell (10); A first sensor (52) that detects and measures the temperature change of the cooling water passing through the second refrigerant line (CL2), converts it into a signal, and transmits it to the control module (60); A third refrigerant line (CL3) connecting the first refrigerant line (CL1) and the second refrigerant line (CL2); A bypass valve (53) installed in the middle of the third refrigerant line (CL3) and controlling the amount of coolant circulated into the interior of the shell (31) through the second refrigerant line (CL2) according to the output and reaction heat fluctuation of the fuel cell (10); A second sensor (54) that detects and measures changes in temperature and pressure within the fuel tank (20), converts them into signals, and transmits them to the control module (60); A fuel pump (55) installed in the middle of the first fuel line (AL1) and sending liquid ammonia in the fuel tank (20) to the heat exchanger (30); A compressor (56) installed in the middle of the third fuel line (AL3) and pressurizing at least one of hydrogen or a mixture of hydrogen and nitrogen that has passed through the gas purification unit (50) and sending it to the fuel cell (10); and A blower (57) that supplies air (oxygen) to the fuel cell (10) and the reactor (40); An ammonia-based power pack integrated thermal management system, characterized by further comprising:

5. In any one of paragraphs 1 to 3, A fourth fuel line (AL4) connecting the middle of the above fuel tank (20) and the first fuel line (AL1); A regulator (64) installed in the middle of the fourth fuel line (AL4) and configured to supply gaseous ammonia in the fuel tank (20) to the heat exchanger (30) through the first fuel line (AL1) when the pressure in the fuel tank (20) is above a certain range; A first opening / closing valve (65) installed in the middle of the first fuel line (AL1) and controlling the flow rate and flow of liquid ammonia supplied from the fuel tank (20) to the heat exchanger (30); and A first check valve (66) installed in the middle of the first fuel line (AL1) and automatically restricting the flow of liquid ammonia to prevent backflow; An ammonia-based power pack integrated thermal management system, characterized by further comprising:

6. In any one of paragraphs 1 to 3, A fifth fuel line (AL5) connecting the middle of the above fuel tank (20) and the second fuel line (AL2); and A pressure regulating valve (74) installed in the middle of the fifth fuel line (AL5) and controlling gaseous ammonia flowing through the fifth fuel line (AL5) to be sent into the interior of the fuel tank (20) in order to increase the supply pressure of liquid ammonia and the internal pressure of the fuel tank (20); An ammonia-based power pack integrated thermal management system, characterized by further comprising:

7. In any one of paragraphs 1 to 3, A fourth refrigerant line (CL4) connected to the second refrigerant line (CL2) and allowing the cooling water flowing in the second refrigerant line (CL2) to flow in a bypass; A radiator (83) installed in the middle of the fourth refrigerant line (CL4) and dissipating the heat of the cooling water flowing in the fourth refrigerant line (CL4) into the atmosphere; and A second opening / closing valve (84) installed in the middle of the fourth refrigerant line (CL4) and controlling the flow rate and amount of coolant supplied from the fuel cell (10) to the radiator (83); An ammonia-based power pack integrated thermal management system, characterized by further comprising:

8. In any one of paragraphs 1 to 3, A preheater (90) installed on the first fuel line (AL1) and recovering heat from the reaction product discharged from the reactor (40) and exchanging heat with liquid ammonia entering the heat exchanger (30); An ammonia-based power pack integrated thermal management system, characterized by further comprising:

9. In any one of paragraphs 1 to 3, A first three-way valve (86) installed in the middle of the third fuel line (AL3) and changing and controlling the flow direction of gas; A second three-way valve (87) installed in the middle of the above gas recovery line (GL) and changing and controlling the flow direction of gas; and A direction changing pipe (88) connecting the first three-way valve (86) and the second three-way valve (87); Including more, An ammonia-based power pack integrated heat management system characterized in that at least one of hydrogen or a mixture of hydrogen and nitrogen that has passed through the gas purification unit (50) is supplied directly to the reactor (40) through the diversion pipe (88) without passing through the fuel cell (10) by controlling the first three-way valve (86) and the second three-way valve (87).

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