Apparatus for cooling fuel cell stack

Abstract

The present invention relates to an apparatus for cooling a fuel cell stack, the apparatus comprising: a first refrigerant line through which a working fluid flows; a fuel cell stack disposed in the first refrigerant line; a condenser provided in the first refrigerant line and located on a downstream side of the fuel cell stack; a pressure control valve provided in the first refrigerant line and located on a downstream side of the condenser; and a fluid pump disposed in the first refrigerant line and located on a downstream side of the pressure control valve.

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority and benefit of Korean Patent Application No. 10 - 2023 - 0181124, filed with the Korean Intellectual Property Office on December 13, 2023, the entire contents of which are incorporated herein by reference. Technical field

[0003] The present invention relates to a device for cooling a fuel cell stack. Background art

[0004] As concerns about energy efficiency and environmental pollution issues are increasing, there is a need to develop eco - friendly vehicles that can substantially replace internal combustion engine vehicles. Generally, eco - friendly vehicles are classified into electric vehicles that use electricity generated by fuel cells as a power source for driving, and hybrid vehicles that use an engine and a fuel cell for driving.

[0005] Electric vehicles using fuel cells generate driving force by converting chemical reactions into electrical energy. Specifically, electric vehicles generate electricity using the chemical reaction between oxygen and hydrogen. During this process, since heat is generated due to the chemical reaction inside the fuel cell, effectively removing the heat generated by the fuel cell is crucial for ensuring the performance of the fuel cell.

[0006] As the target driving performance and traction performance of fuel cell electric vehicles increase, the number or capacity of fuel cell stacks increases. Therefore, the heat generated by the fuel cell stack increases, which increases the cooling load.

[0007] Therefore, there is a need to develop a new cooling system that can effectively cool the fuel cell stack.

[0008] The above information disclosed in the background art section is only for enhancing the understanding of the background of the present invention. Therefore, the background art section may contain information that does not constitute part of the prior art known to those skilled in the art. Summary of the invention

[0009] The present invention provides a device for cooling a fuel cell stack and a vehicle including the device, which can improve the cooling performance of the fuel cell stack.

[0010] A device for cooling a fuel cell stack according to an embodiment of the present invention may include: a first refrigerant pipeline through which a working fluid flows; a fuel cell stack disposed in the first refrigerant pipeline; a condenser disposed in the first refrigerant pipeline and located on the downstream side of the fuel cell stack; a pressure control valve disposed in the first refrigerant pipeline and located on the downstream side of the condenser; and a fluid pump disposed in the first refrigerant pipeline and located on the downstream side of the pressure control valve.

[0011] In several embodiments, the device further includes: a storage tank disposed in the first refrigerant pipeline and located between the pressure control valve and the fluid pump.

[0012] In several embodiments, the device further includes: a connecting pipeline configured to branch from the first refrigerant pipeline between the fluid pump and the fuel cell stack and merge into the first refrigerant pipeline between the fuel cell stack and the condenser. The device further includes: a first valve disposed at the position where the connecting pipeline branches from the first refrigerant pipeline; and a cathode oxygen depletion (COD) heater disposed in the connecting pipeline.

[0013] In several embodiments, the device further includes: a second refrigerant pipeline configured to branch from the first refrigerant pipeline between the first valve and the fuel cell stack and merge into the first refrigerant pipeline between the condenser and the pressure control valve. The device further includes: a second valve disposed at the intersection of the second refrigerant pipeline and the first refrigerant pipeline; and a heater core disposed in the second refrigerant pipeline.

[0014] In several embodiments, the device further includes: an ion filter disposed in the second refrigerant pipeline and on the downstream side of the heater core.

[0015] In several embodiments, the operating modes of the device include: a first operating mode for cooling the fuel cell stack; a second operating mode for raising the temperature of the fuel cell stack; and a third operating mode for cooling the fuel cell stack and heating the vehicle interior.

[0016] In several embodiments, in the first operating mode: the first valve operates to close the passage between the first refrigerant pipeline and the connecting pipeline; the second valve operates to close the passage between the first refrigerant pipeline and the second refrigerant pipeline; and the working fluid circulates sequentially through the pressure control valve, the fluid pump, the fuel cell stack, and the condenser.

[0017] In several embodiments, in the second operating mode: the first valve operates to connect the first refrigerant pipeline and the connecting pipeline; the second valve operates to close the passage between the first refrigerant pipeline and the second refrigerant pipeline; and the working fluid circulates sequentially through the pressure control valve, the fluid pump, the cathode oxygen depletion heater, and the condenser.

[0018] In several embodiments, in the third operating mode: the first valve operates to close the passage between the first refrigerant pipeline and the connecting pipeline; the second valve operates to connect the first refrigerant pipeline and the second refrigerant pipeline; a part of the working fluid circulates sequentially through the pressure control valve, the fluid pump, the fuel cell stack, and the condenser; and the remaining part of the working fluid circulates sequentially through the pressure control valve, the fluid pump, and the heater core.

[0019] In several embodiments, the apparatus further comprises: a first temperature sensor configured to measure the temperature of the fuel cell stack; a second temperature sensor configured to measure the external air temperature; and a controller configured to control the flow rate of the working fluid flowing along the first refrigerant pipeline such that the working fluid in the fuel cell stack evaporates only within a preset dryness range based on the temperature of the fuel cell stack and the external air temperature measured by the first temperature sensor and the second temperature sensor.

[0020] In several embodiments, in the first operation mode or the third operation mode, the controller uses a pressure control valve to control the pressure of the working fluid such that the phase change temperature of the working fluid is lower than the temperature of the fuel cell stack measured by the first temperature sensor and higher than the external air temperature measured by the second temperature sensor.

[0021] In several embodiments, in the first operation mode or the third operation mode, the controller uses a pressure control valve to control the pressure of the working fluid such that the heat absorbed in the fuel cell stack is equal to the heat dissipated from the condenser.

[0022] In several embodiments, in the second operation mode, the controller uses a fluid pump to control the flow rate of the working fluid flowing along the connection pipeline such that the working fluid in the cathode oxygen-consuming heater evaporates only within a preset dryness range.

[0023] A vehicle according to another embodiment includes an apparatus for cooling a fuel cell stack.

[0024] According to an embodiment, the pressure control valve may be provided downstream of the condenser. Thus, the working fluid passing through the fuel cell stack can dissipate heat from the condenser while maintaining a high-pressure state, thereby increasing the maximum cooling capacity of the fuel cell stack.

[0025] The effects obtainable or expected in embodiments of the present invention will be directly or implicitly disclosed in the detailed description of the embodiments of the present invention. In other words, various effects predicted according to the present invention are disclosed in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Since these drawings are for reference in describing embodiments of the present invention, the technical idea of the present invention should not be construed as being limited to the drawings, and wherein:

[0027] Figure 1 is a block diagram showing the structure of an apparatus for cooling a fuel cell stack according to an embodiment of the present invention;

[0028] Figure 2A and Figure 2B is a diagram showing the temperature distribution of a fuel cell stack according to an embodiment of the present invention;

[0029] Figure 3is a diagram showing the operating state of the device for cooling a fuel cell stack according to an embodiment of the present invention in a first operating mode;

[0030] Figure 4 is a diagram showing the operating state of the device for cooling a fuel cell stack according to an embodiment of the present invention in a second operating mode;

[0031] Figure 5 is a diagram showing the operating state of the device for cooling a fuel cell stack according to an embodiment of the present invention in a third operating mode.

[0032] It should be understood that the drawings are not necessarily drawn to scale, but rather present simplified representations of various features illustrating the basic principles of the present invention. For example, certain design features of the present invention, including specific dimensions, orientations, positions, and shapes, are determined in part by the particular intended application and use environment.

[0033] <Explanation of Reference Numerals>

[0034] 10: First refrigerant pipeline

[0035] 11: Fuel cell stack

[0036] 12: Condenser

[0037] 13: Pressure control valve

[0038] 14: Storage tank

[0039] 15: Fluid pump

[0040] 20: Second refrigerant pipeline

[0041] 21: Ion filter

[0042] 22: Heater core

[0043] 29: First valve

[0044] 30: Connecting pipeline

[0045] 31: COD heater

[0046] 39: Second valve

[0047] 40: Controller

[0048] 41: First temperature sensor

[0049] 42: Second temperature sensor

[0050] 43: Third temperature sensor. Detailed Description of the Invention

[0051] The terms used in this document are only for describing specific embodiments of the present invention and are not intended to limit the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. It should be understood that the terms "comprising" and / or "including" as used herein specify the presence of the stated features, wholes, steps, operations, components, and / or parts, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, components, parts, and / or combinations thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0052] The present invention will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the present invention. However, the present invention can be implemented in various different ways and is not limited to the embodiments described herein.

[0053] To clarify the present invention more clearly, parts not relevant to the description are omitted, and the same reference numerals are used throughout the specification to denote the same or equivalent components.

[0054] In addition, the dimensions and thicknesses of each component shown in the drawings are arbitrarily represented for convenience of description. Therefore, the present invention is not necessarily limited to the drawings, and the thicknesses are enlarged to clearly express each part and region.

[0055] For convenience of description, the suffixes "module", "unit", "part", and / or "section" of the components used in the following description may be used together or interchangeably, but the suffixes themselves do not have different meanings or functions.

[0056] Furthermore, when determining that a detailed description of the prior art related to the present invention may obscure the gist of the embodiments of the present invention during the description of the embodiments of the present invention, the detailed description thereof will be omitted.

[0057] In addition, it should be understood that the drawings are only for those skilled in the art to easily understand the embodiments disclosed in this specification. The technical spirit or inventive concept disclosed in this specification is not limited by the drawings and includes all changes, equivalents, or alternatives within the spirit and technical scope of the present invention.

[0058] Terms including ordinal numbers such as "first", "second", etc. may be used to describe various components, but the components are not limited to these terms.

[0059] Hereinafter, unless the context clearly indicates otherwise, the singular expression of "one" or "a single" can be interpreted as a singular or plural expression. The terms used are only for distinguishing one component from another.

[0060] When a component, device, element, etc. of the present invention is described as having a purpose or performing an operation, function, etc., the component, device, or element should be considered herein as "configured" to achieve the purpose or perform the operation or function.

[0061] Hereinafter, a device for cooling a fuel cell stack according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0062] Figure 1 is a block diagram showing the structure of a device for cooling a fuel cell stack according to an embodiment.

[0063] As Figure 1 shown, the device for cooling a fuel cell stack according to an embodiment may include: a first refrigerant line 10 through which a working fluid flows, a fuel cell stack 11, a condenser 12, a pressure control valve 13, and a fluid pump 15 provided in the first refrigerant line 10.

[0064] The working fluid flowing through the first refrigerant line 10 may be a two-phase fluid (or refrigerant) that changes phase according to changes in temperature and / or pressure. The two-phase fluid (or refrigerant) according to one embodiment may be Novec TM 649.

[0065] When using a two-phase fluid (or refrigerant) as an example of the working fluid, when the working fluid evaporates or condenses, the mixing effect generated by the density difference between the liquid phase and the gas phase can significantly increase the convective heat transfer coefficient.

[0066] In addition, when the two-phase fluid (or refrigerant) exchanges heat with a heat exchange object (e.g., the fuel cell stack 11) (e.g., when the two-phase fluid evaporates or condenses), since the two-phase fluid undergoes a phase change, the temperature change of the two-phase fluid is minimal. Therefore, when the two-phase fluid exchanges heat with the heat exchange object, a relatively large temperature difference between the two-phase fluid and the heat exchange object can be maintained. In contrast, a single-phase fluid such as a coolant undergoes a relatively large temperature change during heat exchange, resulting in a relatively small temperature difference between the single-phase fluid and the heat exchange object.

[0067] Figure 2A is a temperature distribution diagram in the fuel cell stack 11 when the working fluid is a two-phase fluid (e.g., refrigerant). Figure 2B is a temperature distribution diagram in the fuel cell stack 11 when the working fluid is a single-phase fluid (e.g., coolant).

[0068] Referring to Figure 2A , in the endothermic process where the working fluid absorbs heat from the fuel cell stack 11, the working fluid absorbs heat from the fuel cell stack 11 while changing phase from a liquid to a gas (e.g., a two-phase fluid), such that the temperature difference between the fuel cell stack 11 and the working fluid is relatively large.

[0069] Refer to Figure 2B During the endothermic process in which the working fluid absorbs heat from the fuel cell stack 11, the temperature of the working fluid increases as the working fluid absorbs heat from the fuel cell stack 11. Therefore, the temperature difference between the fuel cell stack 11 and the working fluid is relatively small.

[0070] Since the two-phase fluid exchanges heat with the heat exchange object (fuel cell stack 11) while maintaining a predetermined temperature, as described above, the temperature distribution in the fuel cell stack 11 can be kept uniform, and thus the power generation efficiency of the fuel cell stack 11 can be improved.

[0071] The fuel cell stack 11 disposed in the first refrigerant pipeline 10 can generate electric power for driving a vehicle by converting the chemical reaction energy of oxygen and hydrogen into electric energy.

[0072] The condenser 12 can be disposed in the first refrigerant pipeline 10 and on the downstream side of the fuel cell stack 11. The condenser 12 can condense the working fluid by using the heat exchange between the external air and the working fluid.

[0073] The pressure control valve 13 can be disposed in the first refrigerant pipeline 10 and on the downstream side of the condenser 12. The pressure control valve 13 can expand the working fluid flowing along the first refrigerant pipeline 10 and adjust the temperature and pressure of the working fluid. The pressure control valve 13 can be an electronic pressure control valve 13 configured to selectively expand the refrigerant.

[0074] In the device for cooling a fuel cell stack according to an embodiment, the pressure control valve 13 is disposed on the downstream side of the condenser 12 so that the working fluid that has passed through the fuel cell stack 11 and the condenser 12 can be kept in a high-pressure state. Therefore, the temperature difference between the working fluid in the condenser 12 and the external air increases, and the heat dissipation performance of the condenser 12 can be improved. In addition, since the heat dissipation performance of the condenser 12 is improved, the cooling performance of the fuel cell stack 11 can be improved. In addition, when only liquid refrigerant is supplied to the pressure control valve 13, the flow stability of the working fluid can be improved.

[0075] The fluid pump 15 can be disposed in the first refrigerant pipeline 10 and on the downstream side of the pressure control valve 13. The fluid pump 15 can pump the working fluid flowing along the first refrigerant pipeline 10 and circulate the working fluid through the first refrigerant pipeline 10.

[0076] If necessary, the storage tank 14 can be disposed in the first refrigerant pipeline 10 and between the pressure control valve 13 and the fluid pump 15. The storage tank 14 can temporarily store the working fluid and supply only liquid refrigerant to the fluid pump 15 stably and steadily.

[0077] The device for cooling a fuel cell stack according to an embodiment may further include: a connection pipeline 30 configured to branch from a first refrigerant pipeline 10 between a fluid pump 15 and the fuel cell stack 11 and connect to the first refrigerant pipeline 10 between the fuel cell stack 11 and a condenser 12. The device for cooling a fuel cell stack may further include: a first valve 29 provided at a position where the connection pipeline 30 branches from the first refrigerant pipeline 10; and a cathode oxygen depletion (COD) heater 31.

[0078] The first valve 29 may be installed between the fluid pump 15 and the fuel cell stack 11 and is provided at a position where the connection pipeline 30 branches from the first refrigerant pipeline 10. The first valve 29 may be implemented as a three-way valve. According to the operation of the first valve 29, the first refrigerant pipeline 10 and the connection pipeline 30 may be fluidly connected to each other, or the first refrigerant pipeline 10 and the connection pipeline 30 may be fluidly disconnected.

[0079] The COD heater 31 may generate heat by the electric energy generated by the fuel cell stack 11. For example, during cold start of the fuel cell stack 11, when the supply of the working fluid to the fuel cell stack 11 is cut off, when the fuel cell stack 11 automatically generates heat, the temperature of the fuel cell stack 11 rises, and the electric energy generated by the fuel cell stack 11 may be consumed by the COD heater 31. The heat generated by the COD heater 31 may be used to heat the interior of the vehicle, or to raise the temperature of the coolant in other cooling devices in the vehicle.

[0080] The device for cooling a fuel cell stack according to an embodiment may include: a second refrigerant pipeline 20 configured to branch from the first refrigerant pipeline 10 located between the first valve 29 and the fuel cell stack 11 and converge with the first refrigerant pipeline 10 between the condenser 12 and a pressure control valve 13. The device for cooling a fuel cell stack may further include: a second valve 39 provided at the convergence of the second refrigerant pipeline 20 and the first refrigerant pipeline 10; and a heater core 22 provided in the second refrigerant pipeline 20.

[0081] The second valve 39 may be installed between the condenser 12 and the fluid pump 15 and is provided at the convergence of the second refrigerant pipeline 20 and the first refrigerant pipeline 10. The second valve 39 may be implemented as a three-way valve. According to the operation of the second valve 39, the first refrigerant pipeline 10 and the second refrigerant pipeline 20 may be fluidly connected to each other, or the first refrigerant pipeline 10 and the second refrigerant pipeline 20 may be fluidly disconnected.

[0082] The heater core 22 may heat the interior of the vehicle through heat exchange between the working fluid and the air inside the vehicle.

[0083] If necessary, an ion filter 21 may be provided in the second refrigerant line 20. The ion filter 21 may be provided on the downstream side of the heater core 22. The ion filter 21 can reduce the conductivity of the working fluid by removing ions from the working fluid. As described above, the ion filter 21 can reduce the conductivity of the working fluid, which can prevent the insulation resistance of the fuel cell stack 11 from being broken down or deteriorated.

[0084] The apparatus for cooling a fuel cell stack according to an embodiment may further include: a first temperature sensor 41 configured to measure the temperature of the fuel cell stack 11; a second temperature sensor 42 configured to measure the outside air temperature; and a controller 40 configured to control the operations of the pressure control valve 13 and the fluid pump 15. The controller 40 may control the operations of the pressure control valve 13 and the fluid pump 15 based on the temperature of the fuel cell stack 11 measured by the first temperature sensor 41 and the outside air temperature measured by the second temperature sensor 42.

[0085] The sensor data or information indicating the temperature of the fuel cell stack 11 measured by the first temperature sensor 41 and the outside air temperature measured by the second temperature sensor 42 may be transmitted or sent to the controller 40.

[0086] The controller 40 may use the pressure control valve 13 to control the pressure (or temperature) of the working fluid and use the fluid pump 15 to control the flow rate of the working fluid based on the temperature of the fuel cell stack 11 and the outside air temperature.

[0087] To this end, the controller 40 may be implemented as one or more processors operated by a preset program and program instructions, and the preset program and program instructions are programmed to execute the steps of the method for cooling the fuel cell stack 11 according to the present invention through the one or more processors. The preset program and program instructions programmed to execute the steps of the method for cooling the fuel cell stack may be stored in the memory of the controller.

[0088] Hereinafter, the operation of the apparatus for cooling a fuel cell stack according to an embodiment will be described in detail with reference to the drawings.

[0089] The operation modes of the apparatus for cooling a fuel cell stack according to an embodiment may include a first operation mode, a second operation mode, and a third operation mode.

[0090] The first operation mode is an operation mode for cooling the fuel cell stack 11, the second operation mode is an operation mode for raising the temperature of the fuel cell stack 11 during cold start, and the third operation mode is an operation mode for cooling the fuel cell stack 11 and heating the interior of the vehicle.

[0091] Refer to Figure 3, in the first operation mode, the first valve 29 can operate to close the first refrigerant pipeline 10 and the connecting pipeline 30, and the second valve 39 can operate to close the connection or passage between the first refrigerant pipeline 10 and the second refrigerant pipeline 20. In the first operation mode, the working fluid can sequentially circulate through the pressure control valve 13, the fluid pump 15, the fuel cell stack 11, and the condenser 12. In the first operation mode, the working fluid only circulates along the first refrigerant pipeline 10.

[0092] Therefore, the working fluid heated in the fuel cell stack 11 can be condensed in the condenser 12 while dissipating heat, and the working fluid condensed in the condenser 12 expands when passing through the pressure control valve 13 to reduce the pressure. The working fluid depressurized in the pressure control valve 13 can be pumped by the fluid pump 15, circulate along the first refrigerant pipeline 10, and be supplied to the fuel cell stack 11. In addition, the working fluid flowing into the fuel cell stack 11 can absorb the heat generated in the fuel cell stack 11 while exchanging heat with the fuel cell stack 11. The fuel cell stack 11 can be cooled through the above process.

[0093] Since the condenser 12 is provided on the upstream side of the pressure control valve 13, in the first operation mode, the working fluid passing through the fuel cell stack 11 can dissipate heat while being maintained at a high pressure state in the condenser 12. Therefore, the maximum cooling capacity (or heat absorption capacity) of the fuel cell stack 11 can be improved.

[0094] In the first operation mode, during the heat absorption process in which the working fluid absorbs the heat generated by the fuel cell stack 11, the controller 40 controls the flow rate of the working fluid by controlling the fluid pump 15 based on the temperature of the fuel cell stack 11 and the external air temperature measured by the first temperature sensor 41 and the second temperature sensor 42. Therefore, the working fluid in the fuel cell stack 11 can evaporate within a preset dryness range (for example, 0.4 to 0.6). Therefore, overheating of the working fluid can be prevented.

[0095] In the first operation mode, during the pressure control process in which the working fluid expands through the pressure control valve 13, the controller 40 can control the pressure (or temperature) of the working fluid. Thus, the phase change temperature of the working fluid is controlled using the pressure control valve 13 such that the phase change temperature of the working fluid is lower than the temperature of the fuel cell stack 11 measured by the first temperature sensor 41 and higher than the temperature of the external air measured by the second temperature sensor 42. Optionally, during the pressure control process, the controller 40 can control the pressure of the working fluid by using the pressure control valve 13 such that the heat absorbed by the fuel cell stack 11 is equal to the heat dissipated by the condenser 12. As described above, based on the air temperature on the condenser 12 side which is the heat dissipation part, the pressure (or temperature) of the working fluid is controlled by the pressure control valve 13. Therefore, the liquid working fluid can be supplied to the pressure control valve 13, and the flow stability of the working fluid supplied to the pressure control valve 13 can be ensured.

[0096] Referring to Figure 4 , in the second operation mode, the first valve 29 can operate to connect the first refrigerant pipeline 10 and the connection pipeline 30, and the second valve 39 can operate to close the first refrigerant pipeline 10 and the second refrigerant pipeline 20. The working fluid can circulate successively through the pressure control valve 13, the fluid pump 15, the COD heater 31, and the condenser 12. In the second operation mode, the working fluid circulates along the first refrigerant pipeline 10 and the connection pipeline 30.

[0097] Therefore, the working fluid heated when passing through the COD heater 31 can be condensed in the condenser 12 while dissipating heat. The working fluid that has been condensed in the condenser 12 can be depressurized when passing through the pressure control valve 13. The working fluid that has been depressurized in the pressure control valve 13 can be pumped by the fluid pump 15, circulated through the first refrigerant pipeline 10 and the connection pipeline 30, and supplied to the COD heater 31. In addition, the working fluid introduced into the COD heater 31 can absorb the heat generated in the COD heater 31 while exchanging heat with the COD heater 31. Therefore, it is possible to prevent the working fluid from being supplied to the fuel cell stack 11 during cold start. Thus, the temperature of the fuel cell stack 11 rises when generating power and heat, and the electric energy generated by the fuel cell stack 11 is consumed by the COD heater 31. In other words, the COD heater 31 can generate heat by using the electric energy generated by the fuel cell stack 11.

[0098] In the second operation mode, the working fluid passing through the COD heater 31 can dissipate heat while being maintained in a high-pressure state in the condenser 12.

[0099] In the second operation mode, during the endothermic process in which the heat generated by the COD heater 31 is absorbed by the working fluid, the controller 40 can control the flow rate and pressure of the working fluid by controlling the fluid pump 15 and the pressure control valve 13 based on the temperature of the COD heater 31 measured by the third temperature sensor 43. Accordingly, the working fluid in the COD heater 31 can be evaporated only within a preset dryness range (e.g., 0.4 to 0.6). Accordingly, overheating of the working fluid can be prevented.

[0100] Referring Figure 5 , in the third operation mode, the first valve 29 can operate to close the connection or passage between the first refrigerant line and the connection line 30, and the second valve 39 can operate to connect the first refrigerant line and the second refrigerant line 20. In the third operation mode, the working fluid can circulate sequentially through the pressure control valve 13, the fluid pump 15, the fuel cell stack 11, and the condenser 12. In addition, the working fluid can circulate sequentially through the pressure control valve 13, the fluid pump 15, the heater core 22, and the ion filter 21. In other words, the working fluid depressurized in the pressure control valve 13 and pumped by the fluid pump 15 can flow to the fuel cell stack 11 and also flow to the heater core 22.

[0101] Accordingly, the working fluid heated in the fuel cell stack 11 can dissipate heat while being condensed in the condenser 12. The working fluid that has been condensed in the condenser 12 can expand and be depressurized when passing through the pressure control valve 13. The working fluid that has been depressurized in the pressure control valve 13 is pumped by the fluid pump 15 while expanding, circulates along the first refrigerant line 10, and is supplied to the fuel cell stack 11. In addition, the working fluid introduced into the fuel cell stack 11 can absorb the heat generated by the fuel cell stack 11 when exchanging heat with the fuel cell stack 11. The fuel cell stack 11 is cooled through the above process.

[0102] Meanwhile, the working fluid depressurized in the pressure control valve 13 and pumped by the fluid pump 15 can pass through the heater core 22 and the ion filter 21. The working fluid introduced into the heater core 22 can heat the interior of the vehicle when exchanging heat with the air in the vehicle. The working fluid that has passed through the heater core 22 can pass through the ion filter 21 and be supplied to the pressure control valve 13 through the second valve 39.

[0103] The above process can cool the fuel cell stack 11 and heat the interior of the vehicle.

[0104] Since the condenser 12 is provided upstream of the pressure control valve 13, in the third operation mode, the working fluid flowing through the fuel cell stack 11 can dissipate heat while maintaining a high pressure state in the condenser 12. Accordingly, the maximum cooling capacity (or endothermic capacity) of the fuel cell stack 11 can be increased.

[0105] In the third operation mode, according to the operating conditions, the working fluid cooled in the condenser 12 can be maintained in a liquid state at a high temperature (e.g., 45 to 70 degrees Celsius). Accordingly, a part of the working fluid can be supplied to the heater core 22, which can heat the interior of the vehicle.

[0106] In the third operation mode, during the endothermic process in which the working fluid absorbs the heat generated by the fuel cell stack 11, the heat from the fuel cell stack 11 can be absorbed through the phase change of the working fluid (from liquid to gas). Accordingly, the heat transfer coefficient of the working fluid can be significantly increased compared to a single-phase coolant. Additionally, since the phase change temperature of the working fluid can be maintained at a predetermined temperature during the endothermic process, the temperature difference between the working fluid and the fuel cell stack 11 can be kept large, thereby improving the temperature deviation of the fuel cell stack 11.

[0107] Although embodiments of the present invention have been described above, the present invention is not limited thereto. Accordingly, various modifications can be made and carried out within the scope of the claims, the specification, and the drawings of the present invention, and also fall within the scope of the present invention.

Claims

1. A device for cooling a fuel cell stack, the device comprising: a first refrigerant line through which a working fluid flows; a fuel cell stack disposed in the first refrigerant line; a condenser disposed in the first refrigerant line and located on a downstream side of the fuel cell stack; a pressure control valve disposed in the first refrigerant line and located on a downstream side of the condenser; as well as A fluid pump is provided in the first refrigerant line and is located on a downstream side of the pressure control valve.

2. The apparatus according to claim 1, further comprising: A storage tank is disposed in the first refrigerant pipeline and located between the pressure control valve and the fluid pump.

3. The apparatus according to claim 1, further comprising: a connecting line configured to branch from the first refrigerant line between the fluid pump and the fuel cell stack and merge into the first refrigerant line between the fuel cell stack and the condenser; a first valve disposed at a position where the connecting line branches from the first refrigerant line; and The cathode oxygen consumption heater is arranged in the connecting pipeline.

4. The apparatus according to claim 3, further comprising: a second refrigerant line configured to branch from the first refrigerant line between the first valve and the fuel cell stack and merge into the first refrigerant line between the condenser and the pressure control valve; a second valve, disposed at a junction of the second refrigerant pipeline and the first refrigerant pipeline; as well as A heater core is disposed in the second refrigerant line.

5. The apparatus according to claim 4, further comprising: An ion filter is provided in the second refrigerant line and located on a downstream side of the heater core.

6. The device according to claim 4, wherein: The operating modes of the device include: A first operating mode for cooling the fuel cell stack; a second operating mode for increasing the temperature of the fuel cell stack; and The third operating mode is used to cool the fuel cell stack and heat the vehicle interior.

7. The device according to claim 6, wherein: In the first operating mode: The first valve operates to close a passage between the first refrigerant pipeline and the connecting pipeline; the second valve operates to close a passage between the first refrigerant line and the second refrigerant line; and The working fluid circulates sequentially through the pressure control valve, the fluid pump, the fuel cell stack, and the condenser.

8. The device according to claim 6, wherein: In the second operating mode: The first valve operates to connect the first refrigerant line and the connecting line; the second valve operates to close a passage between the first refrigerant line and the second refrigerant line; and The working fluid circulates sequentially through the pressure control valve, the fluid pump, the cathode oxygen consumption heater, and the condenser.

9. The device according to claim 6, wherein: In the third operating mode: The first valve operates to close a passage between the first refrigerant pipeline and the connecting pipeline; the second valve operates to connect the first refrigerant line and the second refrigerant line; A portion of the working fluid circulates sequentially through the pressure control valve, the fluid pump, the fuel cell stack, and the condenser; and The remaining portion of the working fluid circulates sequentially through the pressure control valve, the fluid pump, and the heater core.

10. The apparatus according to claim 6, further comprising: a first temperature sensor configured to measure a temperature of the fuel cell stack; a second temperature sensor configured to measure an outside air temperature; as well as A controller is configured to control the flow rate of the working fluid flowing along the first refrigerant pipeline so that the working fluid in the fuel cell stack evaporates only within a preset dryness range based on the temperature of the fuel cell stack measured by the first temperature sensor and the second temperature sensor and the external air temperature.

11. The device according to claim 10, wherein: In the first operating mode or the third operating mode, the controller uses the pressure control valve to control the pressure of the working fluid so that the phase change temperature of the working fluid is lower than the temperature of the fuel cell stack measured by the first temperature sensor and higher than the external air temperature measured by the second temperature sensor.

12. The device according to claim 10, wherein: In the first operation mode or the third operation mode, the controller controls the pressure of the working fluid using the pressure control valve so that the amount of heat absorbed in the fuel cell stack is equal to the amount of heat dissipated from the condenser.

13. The device according to claim 10, wherein: In the second operation mode, the controller uses the fluid pump to control the flow rate of the working fluid flowing along the connecting pipeline so that the working fluid in the cathode oxygen consumption heater evaporates only within a preset dryness range.

14. A vehicle comprising the apparatus for cooling a fuel cell stack according to claim 1.

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