Thermal management system for high temperature fuel cell system

Abstract

The invention is applied to the technical field of thermal management of high-temperature fuel cell systems, and discloses a thermal management system of a high-temperature fuel cell system. The thermal management system comprises a cooling medium leading-in pipeline, a hollow cavity and a cooling medium leading-out pipeline. And the hollow cavity is formed by a radiating surface. And the hollow cavity is arranged between the inner wall of the hot box and the electric pile and is not in direct contact with the electric pile. And the hollow cavity is respectively connected with a cooling medium leading-in pipeline and a cooling medium leading-out pipeline. A cooling medium flows into the hollow cavity through the cooling medium guide-in guide pipe and then flows out of the hollow cavity through the cooling medium guide-out pipeline. And the cooling medium absorbs the heat of the electric pile in the hollow cavity. Compared with the mode that the radiating surface is not arranged, the cooling medium can absorb more heat through the radiating surface, and the cooling efficiency is improved. Moreover, the cooling medium does not need to be in direct contact with the galvanic pile, so that the range of selectable types of the cooling medium is expanded, and the thermal management efficiency is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of thermal management of high-temperature fuel cell systems, and in particular to a thermal management system of high-temperature fuel cell systems. Background Art

[0002] A fuel cell is an electrochemical device that converts the chemical energy of a fuel into electrical energy. High-temperature fuel cells, such as solid oxide fuel cells (SOFCs) and molten carbonate fuel cells (MCFCs), operate at high temperatures. The electrochemical reactions within the fuel cell are exothermic, requiring efficient cooling to ensure healthy and stable operation. Furthermore, high-temperature fuel cell systems often incorporate sub-processes such as burners, heat exchangers, and fuel reforming, adding complexity and flexibility to the system's thermal management.

[0003] Current cooling methods for high-temperature fuel cell systems are inefficient. Taking SOFCs as an example, air cooling is currently the primary cooling method. SOFC cells and stacks are primarily constructed of ceramic-based materials. Due to the brittleness and thermal stress of ceramics, water cooling, a common method used in low-temperature fuel cell systems, is difficult to implement. Therefore, high air flow rates are typically used to provide the oxygen required for the electrochemical reaction and also serve as a coolant to cool the stack. Due to air's low specific heat capacity and the thermal safety concerns of the ceramics, air must be preheated to a temperature close to that of the stack. This results in a small temperature difference between the air and the stack, resulting in low cooling efficiency. Consequently, high air flow rates are required, consuming significant fan power. Furthermore, to reduce heat loss in the stack and improve system energy efficiency, the stack is typically placed in a hot box for insulation. The conflict between heat dissipation (air cooling) and thermal insulation necessitates a more efficient cooling method specifically for high-temperature fuel cell systems. Summary of the Invention

[0004] In view of this, the present application provides a thermal management system for a high-temperature fuel cell system, which can improve the cooling efficiency of the high-temperature fuel cell.

[0005] The technical solutions provided in this application are as follows:

[0006] In a first aspect, the present application provides a thermal management system for a high-temperature fuel cell system, the thermal management system comprising a cooling medium inlet pipe, a hollow cavity and a cooling medium outlet pipe, the hollow cavity being composed of a radiation surface, the high-temperature fuel cell system comprising a fuel cell stack, the hollow cavity being arranged in a heat box where the fuel cell stack is placed, the hollow cavity being located between the inner wall of the heat box and the fuel cell stack, the distance, relative area and viewing angle between the hollow cavity and the fuel cell stack corresponding to the radiation heat requirement of the fuel cell stack; the two ends of the hollow cavity being respectively connected to one end of the cooling medium inlet pipe and one end of the cooling medium outlet pipe; the cooling medium inlet pipe is used to transmit cooling medium so that the cooling medium enters the hollow cavity; the hollow cavity is used to absorb the heat generated by the fuel cell stack based on the radiation surface, and to store and transport the cooling medium so that the cooling medium absorbs the heat generated by the fuel cell stack after heat exchange with the hollow cavity; the cooling medium outlet pipe is used to transmit cooling medium so that the cooling medium is output from the hollow cavity.

[0007] In a possible implementation, the other end of the cooling medium outlet pipe is connected to a first waste heat utilization system, and the first waste heat utilization system is used to utilize the cooling medium to perform a production task or a processing task.

[0008] In a possible implementation, the first waste heat utilization system is a waste heat power generation system or a waste heat heating system.

[0009] In one possible implementation, the thermal management system also includes a first heat exchange subsystem, the other end of the cooling medium outlet pipe is connected to the first heat exchange subsystem, and the first heat exchange subsystem is also connected to the outlet of the fuel cell stack through a first transmission pipe. The first transmission pipe is used to transmit the gas heated by the electrochemical reaction of the high-temperature fuel cell system, and the first heat exchange subsystem is used to perform heat exchange between the gas and the cooling medium. The first heat exchange subsystem is also connected to the second waste heat utilization system through a second transmission pipe, and the second transmission pipe is used to transmit the cooling medium. The second waste heat utilization system is used to use the cooling medium to perform production tasks or processing tasks.

[0010] In a possible implementation, the first heat exchange subsystem is further connected to the second waste heat utilization system via a third transmission pipeline, the third transmission pipeline is used to transmit the gas, and the second waste heat utilization system is further used to utilize the heat of the gas to provide energy.

[0011] In a possible implementation, the first heat exchange subsystem is further connected to the third waste heat utilization system via a fourth transmission pipeline. The fourth transmission pipeline is used to transmit the gas, and the third waste heat utilization system is used to utilize the heat of the gas to provide energy.

[0012] In a possible implementation, the type of the cooling medium corresponds to a temperature reduction requirement, or the type of the cooling medium corresponds to a waste heat utilization requirement.

[0013] In a possible implementation, the phase change temperature of the cooling medium is determined based on the pressure and material composition of the cooling medium, and the outlet temperature of the cooling medium output from the cooling medium outlet pipe is determined based on the flow rate of the cooling medium.

[0014] In one possible implementation, the first transmission pipeline is connected to the first heat exchange subsystem through a burner, and the burner is used to burn the fuel and air discharged from the outlet of the fuel cell stack that do not participate in the electrochemical reaction, or directly burn the supplementary fuel and air to generate flue gas.

[0015] In a possible implementation, the first transmission pipeline is connected to the first heat exchange subsystem via a second heat exchange subsystem, and the second heat exchange subsystem is used to perform heat exchange on the air or fuel input into the fuel cell stack.

[0016] In a possible implementation, the hollow cavity includes a plurality of sub-cavities, each of which is used to transmit a different type of cooling medium.

[0017] It can be seen that this application has the following beneficial effects:

[0018] The present application provides a thermal management system for a high-temperature fuel cell system, comprising a cooling medium inlet pipe, a hollow cavity, and a cooling medium outlet pipe. The hollow cavity is constructed using a radiating surface. The radiating surface can absorb the heat generated by the fuel cell stack. The hollow cavity is located between the inner wall of the heat box and the fuel cell stack and is not in direct contact with the stack. The distance, relative area, and viewing angle between the hollow cavity and the fuel cell stack correspond to the requirements for utilizing the radiant heat of the fuel cell stack, so that the hollow cavity can fully absorb the radiant heat of the fuel cell stack. The hollow cavity is connected to a cooling medium inlet pipe and a cooling medium outlet pipe, respectively. The cooling medium flows into the hollow cavity through the cooling medium inlet pipe and then flows out of the hollow cavity through the cooling medium outlet pipe. The cooling medium absorbs the heat of the fuel cell stack in the hollow cavity. Compared to a case where no radiating surface is provided, the cooling medium can absorb more heat through the radiating surface, thereby improving cooling efficiency. In addition, by transmitting the cooling medium through the hollow cavity, the cooling medium does not need to directly contact the fuel cell stack, which expands the range of optional cooling medium types. The cooling medium can be other types of cooling medium besides heated air, which can further improve the efficiency of absorbing heat compared to heated air. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic structural diagram of a SOFC system provided in an embodiment of the present application;

[0020] Figure 2 A schematic diagram of the structure of a thermal management system provided in an embodiment of the present application;

[0021] Figure 3 A schematic diagram of the structure of another thermal management system provided in an embodiment of the present application;

[0022] Figure 4 A schematic diagram of the structure of another thermal management system provided in an embodiment of the present application;

[0023] Figure 5 A schematic structural diagram of another first transmission pipeline provided in an embodiment of the present application;

[0024] Figure 6 A schematic structural diagram of another first transmission pipeline provided in an embodiment of the present application;

[0025] Figure 7 A schematic diagram of the structure of another thermal management system provided in an embodiment of the present application;

[0026] Figure 8 A schematic diagram of the structure of another thermal management system provided in an embodiment of the present application;

[0027] Figure 9 A schematic diagram of the structure of another thermal management system provided in an embodiment of the present application;

[0028] Figure 10 A schematic structural diagram of another thermal management system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to facilitate understanding and explanation of the technical solutions provided by the embodiments of the present application, the background technology of the present application will be described below.

[0030] See also Figure 1 As shown, Figure 1 A structural diagram of a SOFC system provided in an embodiment of the present application. The SOFC system includes two heat exchangers (HTX), SOFC, a burner, and pipes connecting the various devices. The two heat exchangers are, for example, HTX1 and HTX2. HTX1 is used to heat the air input to the SOFC. HTX2 is used to heat the fuel input to the SOFC. Heating the air and fuel is, on the one hand, a requirement for energy balance, and on the other hand, to reduce the temperature difference between the air and fuel and the SOFC to avoid thermal shock to the SOFC. The SOFC stack is the core component. The stack consists of a number of single cells, which are assembled together in series, parallel or mixed to increase the overall power output. The single cell mainly includes an electrolyte, an anode (fuel electrode), a cathode (air electrode) and a connector (or bipolar plate). The air heated by HTX1 is input to the cathode, and the fuel heated by HTX2 is input to the anode. The fuel and air input into the SOFC undergo an electrochemical reaction to generate electricity. The unreacted fuel and air flow into the burner and can be burned with the air and fuel used for supplementary combustion to generate high-temperature flue gas. The flue gas can be used to heat the air in HTX1 and heat the fuel in HTX2.

[0031] The main body of an SOFC consists of a large amount of ceramic-based material. Ceramics are brittle and subject to thermal stress. Direct water cooling can cause the ceramic to fracture. Currently, heated air is commonly used to cool SOFCs. Specifically, the air heated by the HTX1 serves as both the cathode reactant gas and the cooling gas. The temperature difference between the HTX1-heated air and the SOFC temperature is typically controlled between 30 and 50 degrees Celsius (°C), or even below 30°C. This small temperature difference requires a large amount of air for cooling. Furthermore, to reduce heat loss and enhance thermal protection, the stack and high-temperature auxiliary components are often integrated into a hot box. High-temperature auxiliary components include heat exchangers and burners. The thermal insulation of the hot box further increases the cooling load, requiring more air for cooling. Cooling with heated air is inefficient, and the large air flow consumes significant fan power, increasing cooling costs. In scenarios where high-temperature fuel cells are used for power generation, using heated air for cooling reduces the overall power generation efficiency of the power generation system.

[0032] Based on this, an embodiment of the present application provides a thermal management system for a high-temperature fuel cell system, comprising a cooling medium inlet conduit, a hollow cavity, and a cooling medium outlet conduit. The hollow cavity is constructed using a radiating surface. The radiating surface can absorb heat generated by the fuel cell stack. The hollow cavity is located between the inner wall of the heat box and the fuel cell stack and does not directly contact the stack. The distance, relative area, and viewing angle between the hollow cavity and the fuel cell stack correspond to the requirements for utilizing the radiant heat of the fuel cell stack, allowing the hollow cavity to fully absorb the radiant heat from the fuel cell stack. The hollow cavity is connected to a cooling medium inlet conduit and a cooling medium outlet conduit, respectively. The cooling medium flows into the hollow cavity through the cooling medium inlet conduit and then flows out of the hollow cavity through the cooling medium outlet conduit. Within the hollow cavity, the cooling medium absorbs heat from the fuel cell stack. Compared to a system without a radiating surface, the cooling medium can absorb more heat through the radiating surface, thereby improving cooling efficiency. Furthermore, by transmitting the cooling medium through the hollow cavity, the cooling medium does not need to directly contact the fuel cell stack, expanding the range of optional cooling medium types. The cooling medium can be other types of cooling medium besides heated air, which can further improve the efficiency of absorbing heat compared to heated air.

[0033] An embodiment of the present application provides a thermal management system for a high-temperature fuel cell system, which utilizes the high-temperature radiation energy of the battery or the stack itself, and the cooling medium absorbs the radiated heat of the stack. In addition to the convection heat transfer cooling method of the cooling air, a radiation cooling method is provided to reduce the amount of cooling air and the power consumption of the fan, thereby improving the cooling efficiency of the high-temperature fuel cell. Due to the non-contact cooling, the cooling medium can be a phase change or non-phase change medium, and its inlet temperature is not limited by the rapid cooling and thermal stress risks of the ceramic body. The phase change temperature of the cooling medium can be regulated by regulating the pressure, material composition, etc. of the cooling medium. The cooling medium outlet temperature and the thermal management load of the system are regulated by regulating the cooling medium flow rate, inlet temperature, etc. The heated cooling medium (such as a low-boiling-point working fluid) can be directly used for waste heat utilization (such as waste heat power generation of the Organic Rankine Cycle (ORC)). Furthermore, the cooling medium can also be coupled with heat sources of different temperatures in the high-temperature fuel cell system (for example: high-temperature gas at the outlet of the fuel cell stack, flue gas at the outlet of the burner) and heat demands (for example: gas heat recovery at the inlet of the fuel cell stack, heat required for the fuel reforming reactor, heat required for the water vapor vaporization reaction, and system waste heat recovery), so as to optimize the thermal management and comprehensive energy utilization of the high-temperature fuel cell system.

[0034] To facilitate understanding of the technical solution provided in the embodiment of the present application, a thermal management system of a high-temperature fuel cell system provided in the embodiment of the present application is described below with reference to the accompanying drawings.

[0035] See also Figure 2 , which is a schematic diagram of the structure of a thermal management system provided in an embodiment of the present application. The thermal management system includes a cooling medium inlet pipe 201, a hollow cavity 202, and a cooling medium outlet pipe 203. The ends of the hollow cavity 202 are connected to one end of the cooling medium inlet pipe 201 and one end of the cooling medium outlet pipe 203, respectively.

[0036] The cooling medium inlet pipe 201, the hollow cavity 202 and the cooling medium outlet pipe 203 are respectively described in detail below.

[0037] Hollow cavity 202 is constructed with a radiating surface. This surface receives high-temperature radiant heat from the fuel cell stack, allowing the cooling medium transported within hollow cavity 202 to fully absorb the heat and improve cooling efficiency. The present embodiment does not limit the material of the radiating surface; a radiating surface with a certain degree of blackness or absorptivity can be configured to meet the cooling needs of the fuel cell.

[0038] A hollow cavity 202 with a radiating surface is arranged around the device requiring cooling. Specifically, hollow cavity 202 is disposed around the fuel cell stack included in the high-temperature fuel cell system. Hollow cavity 202 is disposed within a hot box housing the fuel cell stack. Hollow cavity 202 is located between the inner wall of the hot box and the fuel cell stack. It should be noted that the fuel cell stack may be referred to simply as a stack.

[0039] The positional relationship between the hollow cavity 202 and the fuel cell stack can be determined based on the need to utilize the radiant heat from the fuel cell stack. The positional relationship between the hollow cavity 202 and the fuel cell stack is based on the distance, relative area, and view factor between the hollow cavity 202 and the fuel cell stack. The view factor reflects the visible spatial angle between the hollow cavity 202 and the fuel cell stack. The view factor represents the percentage of radiant heat emitted by the fuel cell stack that is absorbed by the hollow cavity 202.

[0040] The need to utilize radiant heat from the fuel cell stack can be determined based on the radiant heat generated by the electrochemical reaction of the fuel cell stack, the temperature of the cooling medium after heat exchange between the hollow cavity 202 and the fuel cell stack, and the geometric requirements of the space within the heat box in which the hollow cavity 202 can be arranged. In one possible implementation, the correspondence between different needs for utilizing radiant heat from the fuel cell stack and the positional relationship between the hollow cavity 202 and the fuel cell stack can be determined in advance during the testing phase, so that the corresponding positional relationship between the hollow cavity 202 and the fuel cell stack can be determined subsequently based on the need for utilizing radiant heat from the fuel cell stack.

[0041] In addition, the distance between the hollow cavity 202 and the fuel cell stack must be greater than zero. In other words, the hollow cavity 202 cannot directly contact the fuel cell stack to prevent direct contact between the hollow cavity 202, which transmits the cooling medium and has a lower surface temperature, and the fuel cell stack, which could cause thermal stress in the ceramics of the fuel cell stack. The distance between the hollow cavity 202 and the fuel cell stack can be set according to cooling needs.

[0042] One end of the hollow cavity 202 is connected to one end of the cooling medium inlet pipe 201, and the other end of the hollow cavity 202 is connected to the other end of the cooling medium outlet pipe 203. The cooling medium inlet pipe 201 and the cooling medium outlet pipe 203 are used to transport the cooling medium. The cooling medium enters the hollow cavity 202 through the cooling medium inlet pipe 201 and exits the hollow cavity 202 through the cooling medium outlet pipe 203. As the cooling medium flows through the hollow cavity 202, it absorbs heat generated by the fuel cell stack absorbed by the radiating surface of the hollow cavity 202, thereby cooling the fuel cell stack.

[0043] In one possible implementation, the hollow cavity 202 is a cavity. In another possible implementation, the hollow cavity 202 includes two or more sub-cavities. In the case where the hollow cavity 202 includes multiple sub-cavities, the cooling medium inlet pipe 201 and the cooling medium outlet pipe 203 also include multiple sub-pipes respectively. The number of sub-pipes included in the cooling medium inlet pipe 201 and the number of sub-pipes included in the cooling medium outlet pipe 203 are the same as the number of sub-cavities included in the hollow cavity 202. Each sub-pipe is connected to a sub-cavity. Different sub-cavities in the hollow cavity 202 and the sub-pipes connected to the cavity can be used to transmit different types of cooling media to improve the cooling efficiency and meet different cooling needs.

[0044] The embodiments of the present application do not limit the specific type of cooling medium. The type of cooling medium corresponds to the cooling demand, or the type of cooling medium corresponds to the waste heat utilization demand. As an example, the cooling medium is a low-boiling-point working fluid. A low-boiling-point working fluid is a medium substance with a relatively low boiling point at normal temperature and pressure. Here, the working fluid refers to a medium substance for the mutual conversion of thermal energy and mechanical energy. A low-boiling-point working fluid can absorb heat at a lower temperature and improve the cooling efficiency. Examples of low-boiling-point working fluids include tetrafluoropropylene, propane, and difluoromethane. As another example, the cooling medium is water. As another example, the cooling medium is cooled air.

[0045] In addition, the pressure and flow rate of the cooling medium can be set according to the cooling needs. The temperature of the cooling medium in the hollow cavity 202 is determined based on the pressure, flow rate and type of the cooling medium. The cooling medium is introduced from the cooling medium inlet pipe 201 at a certain pressure. The phase change temperature of the cooling medium is determined based on the pressure at the time of introduction and the material composition of the cooling medium (that is, the type of cooling medium). An introduction device can be set at the inlet of the cooling medium inlet pipe 201. The introduction device is used to introduce the cooling medium into the cooling medium inlet pipe 201. The introduction device is also used to control the flow rate of the cooling medium. The flow rate of the cooling medium affects the outlet temperature of the cooling medium in the cooling medium outlet pipe 203. As an example, the cooling medium is air and the introduction device is a fan.

[0046] based on Figure 2As can be seen from the structure of the thermal management system shown, a hollow cavity 202 consisting of a radiation surface is arranged around the fuel cell stack, and the radiation surface can more fully absorb the heat generated by the fuel cell stack. The cooling medium transmitted in the hollow cavity 202 can absorb the heat of the radiation surface. Compared with no radiation surface, the cooling medium can absorb more heat and improve the cooling efficiency. In addition, the cooling medium is transmitted through the hollow cavity 202, and the cooling medium does not need to directly contact the fuel cell stack, which expands the range of optional cooling medium types. The cooling medium can be other types of cooling media other than heated air, such as water, low-boiling-point working fluid, etc., which can further improve the efficiency of heat absorption compared to heated air.

[0047] In another possible implementation, the cooling medium behind the hollow cavity 202 absorbs a certain amount of heat, and the heat of the cooling medium can be further utilized to realize waste heat utilization of the cooling medium.

[0048] As an example, see Figure 3 As shown, this figure is a schematic structural diagram of another thermal management system provided in an embodiment of the present application. The other end of the cooling medium outlet pipe 203 is connected to the first waste heat utilization system 210. The first waste heat utilization system 210 is used to use the cooling medium to perform production tasks or processing tasks. The embodiment of the present application does not limit the specific type of the first waste heat utilization system 210. For example, the first waste heat utilization system 210 is a waste heat power generation system. The waste heat power generation system can generate electricity using the heat of the cooling medium. For example, the first waste heat utilization system 210 is an organic Rankine cycle (ORC) system. For another example, the first waste heat utilization system 210 directly uses the cooling medium after absorbing heat to perform production tasks or processing tasks. For example, the cooling medium is water. The first waste heat utilization system 210 can use the hot water or water vapor generated after absorbing heat through the hollow cavity to perform other production tasks or processing tasks. For another example, the first waste heat utilization system 210 is a waste heat heating system. The waste heat heating system can use the heat absorbed by the cooling medium to provide heat to the outside.

[0049] In a fuel cell stack, an electrochemical reaction between input fuel and air generates electricity. Fuel and air that have not participated in the electrochemical reaction typically remain in the stack. This unreacted fuel and air also carry a certain amount of heat. In some possible implementations, this heat is further utilized to avoid energy waste.

[0050] The embodiments of the present application do not limit the thermal management method or waste heat utilization method for unreacted fuel and unreacted air. In one possible implementation, the unreacted fuel and unreacted air can adopt a thermal management method and waste heat utilization method that are independent of the cooling medium. Figure 4 As shown, this figure is a structural schematic diagram of another thermal management system provided by an embodiment of the present application. The stack is connected to the second heat exchange subsystem 205 (including HTX1 and HTX2) by a pipe for transmitting unreacted fuel and unreacted air. In HTX2, the unreacted fuel is heat exchanged with the fuel input to the stack to fully utilize the heat. The stack is also connected to the second heat exchange subsystem 205 by another pipe for transmitting unreacted air. In HTX1, the unreacted air is heat exchanged with the air input to the stack to fully utilize the heat.

[0051] In some possible implementations, after heat exchange at HTX2, unreacted fuel is mixed with the fuel at the inlet and reintroduced into the stack, achieving fuel recovery. Fuel recovery can reduce fuel costs. After heat exchange at HTX1, unreacted gas can be discharged or mixed with the gas at the inlet and reintroduced into the stack, achieving gas recovery.

[0052] Figure 4 The thermal management method for unreacted fuel and unreacted air shown is only an example. In another possible implementation, a burner is provided between the outlet of the fuel cell stack and the second heat exchange subsystem (HTX1 and HTX2). The unreacted fuel and unreacted air derived from the outlet of the fuel cell stack are burned in the burner. In the burner, the unreacted fuel and unreacted air burn to generate high-temperature flue gas. The flue gas is input into the second heat exchange subsystem (HTX1 and HTX2) through a pipe, and heat exchange is performed on the fuel and air input into the fuel cell stack inlet, thereby increasing the temperature of the fuel and air entering the fuel cell stack and fully utilizing the heat of the unreacted fuel and unreacted air. In addition, fuel and air can be added to the burner to adjust the air-fuel ratio of the burner and improve the flexibility of the thermal management system.

[0053] The specific structure of the burner can be found in Figures 5-10 The burner-related structure shown.

[0054] The cooling medium can also be coupled with other thermal management methods to optimize the overall thermal management and waste heat utilization of the thermal management system after radiative heating, see below Figures 5-10 Description.

[0055] As another example, the thermal management system also includes a first heat exchange subsystem. The other end of the cooling medium outlet pipe is connected to the first heat exchange subsystem. The first heat exchange subsystem is also connected to the outlet of the fuel cell stack through a first transmission pipe. The first heat exchange subsystem is also connected to the second waste heat utilization system through a second transmission pipe. Among them, the first transmission pipe is used to transmit the gas heated by the electrochemical reaction of the fuel cell stack. For example, the gas heated by the electrochemical reaction of the high-temperature fuel cell system may be the unreacted gas in the fuel cell stack. For another example, the gas heated by the electrochemical reaction of the high-temperature fuel cell system may also be the flue gas generated by further burning the unreacted fuel and unreacted air output by the fuel cell stack using a burner. The gas has a certain temperature and can be used to heat the cooling medium. In addition, the first transmission pipe can also be used to transmit the unreacted fuel in the fuel cell stack.

[0056] The first heat exchange subsystem receives gas from the first transmission pipeline and coolant from the coolant outlet pipeline. The first heat exchange subsystem is used to exchange heat between the gas and the coolant. This allows the coolant to be further heated by the gas at a certain temperature, facilitating the full utilization of the heated coolant for subsequent waste heat recovery.

[0057] In one possible implementation, see Figure 5 As shown in FIG. 1 , this figure is a structural diagram of another thermal management system provided by an embodiment of the present application. The thermal management system further includes a first heat exchange subsystem 204. The first heat exchange subsystem 204 is Figure 5 HTX3 in. The other end of the cooling medium outlet pipe 203 is connected to the first heat exchange subsystem 204. The first heat exchange subsystem 204 is also connected to the fuel cell stack via a first transmission pipe 220. The first heat exchange subsystem 204 is also connected to the second waste heat utilization system 240 via a second transmission pipe 250. The first transmission pipe 220 is connected to the first heat exchange subsystem 204 via the burner 230. The first transmission pipe 220 includes a first sub-pipe 2201 and a second sub-pipe 2202. The first sub-pipe 2201 is used to connect the fuel cell stack and the burner 230. The first sub-pipe 2201 is used to transfer unreacted fuel and unreacted air. The second sub-pipe 2202 is used to connect the burner 230 and the first heat exchange subsystem 204. The second sub-pipe 2202 is used to transfer the flue gas output by the burner 230.

[0058] Burner 230 is used to burn unreacted fuel and air output from the fuel cell stack to generate flue gas. Burner 230 can fully burn the fuel, improving its efficient use, and increase the temperature of the flue gas, which is beneficial for further heating the cooling medium.

[0059] After the first heat exchange subsystem 204 performs heat exchange on the flue gas and the cooling medium, the temperature of the flue gas may still be relatively high, for example, above 200 degrees Celsius, and the waste heat of the flue gas can be further utilized. The flue gas is sequentially introduced into HTX2 for heat exchange with the fuel input to the fuel cell stack, and then introduced into HTX1 for heat exchange with the air input to the fuel cell stack. In this way, the flue gas is used to first heat the cooling medium, and then heat the fuel and air input to the fuel cell stack, making full use of the heat of the flue gas. In addition, the heating priority of the cooling medium is higher, which facilitates the full utilization of the heat of the cooling medium.

[0060] In another possible implementation, the flue gas generated by the burner 230 can be transported to different heat exchange subsystems through multiple pipes to achieve heat exchange. Figure 6 As shown, first transmission pipeline 220 is connected to first heat exchange subsystem 204 via burner 230. First transmission pipeline 220 includes a first sub-pipeline 2201 and a second sub-pipeline 2202. First sub-pipeline 2201 is used to connect the fuel cell stack and burner 230. First sub-pipeline 2201 is used to transfer unreacted fuel and unreacted air. Second sub-pipeline 2202 is used to connect burner 230 and first heat exchanger 204. Second sub-pipeline 2202 is used to transfer a portion of the flue gas output by burner 230.

[0061] Burner 230 is used to burn unreacted fuel and air output from the fuel cell stack to generate flue gas. Burner 230 can fully burn the fuel, improving its efficient use, and increase the temperature of the flue gas, which is beneficial for further heating the cooling medium.

[0062] The first heat exchange subsystem 204 receives high-temperature flue gas transmitted from the second sub-pipe 2202 of the first transmission pipeline 220, and receives cooling medium transmitted from the cooling medium outlet pipeline 203. The first heat exchange subsystem 204 is used to perform heat exchange between the flue gas and the cooling medium. This allows the flue gas to further heat the cooling medium, facilitating the full utilization of the heated cooling medium for subsequent waste heat recovery.

[0063] Figure 6 The second sub-pipe 2202 shown directly connects the burner 230 and the first heat exchange system 204. Furthermore, the burner 230 and the second heat exchange system 205 can also be connected via a pipe to transfer a portion of the flue gas generated by the burner 230. The second heat exchange system 260 uses the captured flue gas to perform heat exchange between the fuel and air input to the fuel cell stack.

[0064] In another possible implementation, the flue gas generated by the burner 230 can first heat the fuel and air input to the fuel cell stack, and then heat the cooling medium. Figure 7 As shown, the thermal management system also includes a second heat exchange subsystem 205. The second heat exchange subsystem 205 includes, for example, HTX1 and HTX2. HTX1 is used for heat exchange to heat the air input to the fuel cell stack. HTX2 is used for heat exchange to heat the fuel input to the fuel cell stack. The second sub-pipeline 2202 passes through the second heat exchange system 205 and is connected to the first heat exchange system 204. The second heat exchange subsystem 205 is used to perform heat exchange between the flue gas generated by the burner 230 and the air or fuel input to the stack. In this way, the flue gas can be used to first heat the air input to the stack or the fuel input to the stack, and then heat the cooling medium, thereby fully utilizing the heat of the flue gas.

[0065] Figure 5-Figure 7 The use of the burner 230 to process the unreacted fuel and the unreacted air is only a possible implementation method, and the present application is not limited thereto. Other devices may also be used to process the unreacted fuel and the unreacted air.

[0066] The above is an introduction to the manner in which the first heat exchange subsystem 204 obtains the cooling medium and gas.

[0067] The first heat exchange subsystem 204 transmits the cooling medium heated by the gas to the second waste heat utilization system 240 through the second transmission pipeline 250. The second waste heat utilization system 240 is used to perform production tasks or processing tasks using the cooling medium. The second waste heat utilization system 240 is, for example, a waste heat power generation system. The waste heat power generation system can generate electricity using the heat absorbed by the cooling medium. The second waste heat utilization system 240 can also directly use the cooling medium after absorbing heat. For example, the cooling medium is water. The second waste heat utilization system 240 can use the hot water or water vapor generated after absorbing heat through the hollow cavity and performing heat exchange in the first heat exchange system 204 to perform other production tasks or processing tasks.

[0068] Figure 5-Figure 7 In the thermal management system shown, the first heat exchange subsystem 204 is connected to the second waste heat utilization system 240 via a second transmission pipeline 250 , and the cooling medium is transmitted via the second transmission pipeline 250 .

[0069] In addition, as an example, the second transmission pipeline is used to transmit the cooling medium and the flue gas. Figure 7 For example, see Figure 8 As shown in FIG, this figure is a structural diagram of another thermal management system provided by an embodiment of the present application. The second transmission pipeline 250 is used to transmit the cooling medium and the flue gas. As another example, the first heat exchange subsystem is also connected to the second waste heat utilization system through a third transmission pipeline. Taking the second sub-pipeline passing through the second heat exchange subsystem (HTX1 and HTX2) as an example, see Figure 9As shown, this figure is a schematic diagram of the structure of another thermal management system provided by an embodiment of the present application. Third transmission pipeline 260 is used to transmit the flue gas after use by first heat exchange subsystem 204. The flue gas after use by first heat exchange subsystem 204 still contains heat. Second waste heat utilization system 240 can also use the heat of the flue gas to provide energy. Second waste heat utilization system 240 can utilize the waste heat of the flue gas used to heat the cooling medium to achieve coupled energy supply between the flue gas and the cooling medium, achieving full energy utilization.

[0070] Figure 9 The scenario shown is that the flue gas and the cooling medium are coupled to provide energy for the same waste heat utilization system. In addition, the flue gas and the cooling medium output by the first heat exchange subsystem can also provide energy independently. Figure 10 , which is a schematic diagram of the structure of another thermal management system provided in an embodiment of the present application. The first heat exchange subsystem 204 is also connected to a third waste heat utilization system 290 via a fourth transmission pipeline 270. The third waste heat utilization system 290 is a separate waste heat utilization system from the second waste heat utilization system 240. The fourth transmission pipeline 270 is used to transmit the flue gas output from the first heat exchange subsystem 204 after use. The third waste heat utilization system 290 is used to utilize the heat of the flue gas transmitted by the fourth transmission pipeline 270 for energy generation. Figure 10 The thermal management system shown can realize independent waste heat utilization of flue gas and cooling medium, meeting the waste heat utilization needs of different scenarios.

[0071] It should be noted that Figure 9 and Figure 10 The thermal management system shown in the figure has the same structure except that the connection method of the waste heat utilization system is different. Figure 9 and Figure 10 The first transmission pipe 220 in the embodiment can be replaced by other connection methods, for example, see Figure 5 or Figure 7 The connection method of the first transmission pipeline 220 shown in the embodiment of the present application will not be repeated.

[0072] The effects of the thermal management system are described below with reference to examples.

[0073] As an example, Figure 9 Taking the structure of the thermal management system shown in the figure as an example, the high-temperature fuel cell system is a SOFC system. The power of the SOFC system is 20 kilowatts (kW). The average performance of the SOFC single cell is: 0.805 volts (V) and 0.35 amperes per square centimeter (A / cm2) at 750°C. 2 ), the stack power is 21.47kW, the anode inlet fuel temperature and the cathode inlet air temperature are constant at 700℃ (maintaining a temperature difference of 50℃ with the SOFC operating temperature), and the fuel utilization rate is 75%.

[0074] The nodes tested are as follows: Node 1 is the node before fuel enters HTX2. Node 2 is the node between HTX2 and the SOFC anode. Node 3 is the node between the SOFC anode and the burner. Node 4 is the node between the fan and HTX1. Node 5 is the node between HTX1 and the SOFC cathode. Node 6 is the node between the SOFC cathode and the burner. Node 7 is the node between the burner and the HTX2 anode. Node 8 is the node between HTX2 and HTX1. Node 9 is the node between HTX1 and HTX3. Node 10 is the node before air enters HTX3.

[0075] Table 1 shows the thermal status of each node in the SOFC system when the thermal management system is not running.

[0076] Table 1

[0077]

[0078] Table 1

[0079] 7 215.658 1.013 794.26 0 0.024 0.195 0.780 8 215.658 1.013 780.14 0 0.024 0.195 0.780 9 215.658 1.013 128.98 0 0.024 0.195 0.780 10 0 1.013 25.00 0 0 0.21 0.79

[0080] Table 2 shows the thermal status of each node in the SOFC system when the thermal management system is running. The radiant heat is 4kW.

[0081] Table 2

[0082]

[0083] Comparing Tables 1 and 2, the following results are obtained: Based on the flow rate detection results at nodes 4-10, it can be seen that after the thermal management system is operational, the required air flow rate entering the SOFC cathode is reduced. The air entering the burner increases (the flow rate at node 10 increases), and the flow rate of flue gas generated by SOFC combustion and the flue gas generated by the burner's complete fuel combustion is relatively reduced. Based on the temperature detection results at nodes 7-9, it can be seen that after the thermal management system is operational, the burner burns more completely, and the temperature of the output flue gas increases. Based on the concentrations of the various gases at nodes 7-9, it can be seen that the burner burns more completely, effectively utilizing the heat generated by combustion.

[0084] As another example, Figure 9 Taking the structure of the thermal management system shown in FIG2 as an example, the present embodiment provides a radiation surface with different radiant heat Q, and the corresponding relationship between the radiant heat Q and the stack power (Pstack) ratio (Q / Pstack), the air stoichiometric ratio, the outlet flue gas temperature, and the radiant area of ​​the radiation surface, as shown in Table 3. The air stoichiometric ratio represents the ratio of the air supply to the air required for the electrochemical reaction of the stack. The comprehensive blackness of the radiation surface is taken as 0.5.

[0085] Table 3

[0086]

[0087] Based on the data in Table 3, it can be seen that when no hollow cavity (radiating surface) is provided, that is, when Q = 0, the air stoichiometric ratio is large, requiring a large air flow rate to cool the stack, resulting in higher fan power consumption. As the amount of radiated heat increases, the cooling medium flowing through the hollow cavity absorbs the heat to achieve cooling, and the air stoichiometric ratio decreases, eliminating the need for a large air flow rate for cooling. Furthermore, due to the SOFC's strong high-temperature radiation capability, the required hollow cavity radiation area is small, making it relatively easy to achieve.

[0088] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the systems or devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0089] It should be understood that in this application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0090] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0091] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0092] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A thermal management system for a high-temperature fuel cell system, characterized in that: The high-temperature fuel cell system includes a fuel cell stack, and the thermal management system includes a cooling medium inlet pipe, a hollow cavity, and a cooling medium outlet pipe; The hollow cavity is formed by a radiation surface, and the hollow cavity is arranged in a heat box in which the fuel cell stack is placed. The hollow cavity is located between the inner wall of the heat box and the fuel cell stack, and the distance, relative area, and view factor between the hollow cavity and the fuel cell stack correspond to the radiation heat requirement of the fuel cell stack; The two ends of the hollow cavity are respectively connected to one end of the cooling medium inlet pipe and one end of the cooling medium outlet pipe; The cooling medium introduction pipe is used to transmit the cooling medium so that the cooling medium enters the hollow cavity; The hollow cavity is used to absorb heat generated by the fuel cell stack based on the radiation surface, and to store and transport the cooling medium, so that the cooling medium absorbs the heat generated by the fuel cell stack after heat exchange with the hollow cavity; The cooling medium outlet pipe is used to transport the cooling medium so that the cooling medium is output from the hollow cavity.

2. The thermal management system of a high-temperature fuel cell system according to claim 1, characterized in that: The other end of the cooling medium outlet pipe is connected to a first waste heat utilization system, which is used to utilize the cooling medium to perform production tasks or processing tasks.

3. The thermal management system of a high-temperature fuel cell system according to claim 2, characterized in that: The first waste heat utilization system is a waste heat power generation system or a waste heat heating system.

4. The thermal management system of a high-temperature fuel cell system according to claim 1, characterized in that: The thermal management system also includes a first heat exchange subsystem. The other end of the cooling medium outlet pipe is connected to the first heat exchange subsystem. The first heat exchange subsystem is also connected to the outlet of the fuel cell stack through a first transmission pipe. The first transmission pipe is used to transmit the gas heated by the electrochemical reaction of the high-temperature fuel cell system. The first heat exchange subsystem is used to perform heat exchange between the gas and the cooling medium. The first heat exchange subsystem is also connected to the second waste heat utilization system through a second transmission pipe. The second transmission pipe is used to transmit the cooling medium. The second waste heat utilization system is used to use the cooling medium to perform production tasks or processing tasks.

5. The thermal management system of a high-temperature fuel cell system according to claim 4, characterized in that: The first heat exchange subsystem is also connected to the second waste heat utilization system through a third transmission pipeline. The third transmission pipeline is used to transmit the gas. The second waste heat utilization system is also used to utilize the heat of the gas to provide energy.

6. The thermal management system of a high-temperature fuel cell system according to claim 4, characterized in that: The first heat exchange subsystem is also connected to the third waste heat utilization system through a fourth transmission pipeline. The fourth transmission pipeline is used to transmit the gas, and the third waste heat utilization system is used to utilize the heat of the gas to provide energy.

7. The thermal management system of a high-temperature fuel cell system according to any one of claims 1 to 6, characterized in that: The type of the cooling medium corresponds to the temperature reduction requirement, or the type of the cooling medium corresponds to the waste heat utilization requirement.

8. The thermal management system of a high-temperature fuel cell system according to any one of claims 1 to 6, characterized in that: The phase change temperature of the cooling medium is determined based on the pressure and material composition of the cooling medium, and the outlet temperature of the cooling medium output from the cooling medium outlet pipe is determined based on the flow rate of the cooling medium.

9. The thermal management system of a high-temperature fuel cell system according to any one of claims 4 to 6, characterized in that: The first transmission pipeline is connected to the first heat exchange subsystem through a burner, and the burner is used to burn the fuel and air discharged from the outlet of the fuel cell stack that do not participate in the electrochemical reaction, or directly burn the supplementary fuel and air to generate flue gas.

10. The thermal management system of a high-temperature fuel cell system according to any one of claims 4 to 6, characterized in that: The first transmission pipeline is connected to the first heat exchange subsystem through a second heat exchange subsystem, and the second heat exchange subsystem is used to perform heat exchange on the air or fuel input into the fuel cell stack.

11. The thermal management system of a high-temperature fuel cell system according to any one of claims 1 to 6, characterized in that: The hollow cavity includes a plurality of sub-cavities, and each sub-cavity is used to transmit a different type of cooling medium.

Images