A high-pressure gas supply and heat exchange system for a high-temperature PEM fuel cell stack

Abstract

This invention discloses a high-pressure gas supply and heat exchange system for a high-temperature PEM fuel cell stack, designed to address the unique and complex gas supply and heat exchange requirements of high-temperature PEM fuel cell stacks, providing effective gas supply and heat exchange while improving the energy utilization efficiency and system stability of the fuel cell stack. The system includes a high-temperature PEM fuel cell stack, a temperature and pressure controlled heat exchanger, a condenser preheating heat exchanger, an air booster, a waste gas pressure recovery device, temperature and pressure sensors, etc., achieving an integrated design for gas supply and heat exchange. The waste gas pressure recovery device recovers the waste gas pressure generated by the fuel cell stack, thereby reducing energy consumption and improving system efficiency. Furthermore, by recovering waste heat to preheat hydrogen and fresh air, the system's energy efficiency is further improved. The system can automatically adjust the intake air flow, temperature, and pressure according to load changes and external environmental conditions, achieving dynamic optimization of energy management. Through intelligent control and an integrated high-efficiency design for heat exchange and pressurization, this invention achieves efficient, safe, and sustainable high-pressure gas supply and heat exchange for high-temperature PEM fuel cell stacks.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and more particularly to a high-pressure gas supply and heat exchange system for a high-temperature proton exchange membrane (PEM) fuel cell stack. This system aims to provide a reliable and efficient integrated gas supply and heat exchange system to address the complex and unique gas supply and heat exchange requirements of high-temperature PEM fuel cell stacks, optimize the gas supply and thermal management of high-temperature PEM fuel cell stacks, and effectively improve the stability of the reactant gas supply and system energy efficiency. Background Technology

[0002] Fuel cells can directly and efficiently convert the chemical energy of fuel into electrical energy, exhibiting high energy conversion efficiency and extremely low noise. Among them, high-temperature PEM fuel cells have attracted much attention due to their numerous outstanding advantages. Firstly, due to their higher operating temperature (typically 120℃-200℃), heat dissipation is relatively easier compared to low-temperature PEM fuel cell stacks, which simplifies the design of the cooling system. Secondly, their requirement for the purity of the hydrogen is much lower than that of commonly used low-temperature PEM fuel cell stacks, thus reducing hydrogen purification costs. Furthermore, they do not require humidification like low-temperature PEM fuel cells, eliminating the need for a humidification system. Therefore, high-temperature PEM fuel cells have broad application prospects. However, despite these advantages, the application of high-temperature PEM fuel cells still faces the following challenges:

[0003] 1. Heating Requirements: Water vapor is generated during the reaction process, and low temperatures can lead to condensation. High-temperature PEM fuel cells typically use phosphoric acid-doped membrane electrode assemblies (MEAs). Water vapor condensation can carry away the phosphoric acid from the MEA, affecting its performance. Therefore, preheating of the intake air is necessary. Furthermore, improper heat exchange design can result in high heating energy consumption.

[0004] 2. Gas Supply Requirements: Unlike low-temperature PEM fuel cells, high-temperature PEM fuel cell stacks typically require a more abundant supply of reactant gases. If the gas supply is insufficient, water vapor supersaturation and condensation can easily occur at the end of the reactant gas, affecting the cell's performance. In this case, it is necessary to pressurize the air supply to several times the atmospheric pressure to achieve an excessive supply of reactant air. However, pressurizing the reactant gas will significantly increase the system complexity and energy consumption.

[0005] 3. Exhaust gas recovery: To reduce the energy consumption of pressurized air supply, exhaust gas recovery and utilization is an important approach. However, during the recovery process, especially when the recovered exhaust gas is mixed with fresh air, the moisture in the exhaust gas is prone to condensation, which can affect the intake air quality or the operation of the turbocharger.

[0006] Existing technologies have not formed a systematic and comprehensive solution for the gas supply and heat exchange design of high-temperature PEM fuel cell stacks. There is an urgent need for an innovative design that can meet the gas supply and heat exchange requirements while improving system performance and energy efficiency.

[0007] In view of the above deficiencies, this invention designs a high-pressure gas supply and heat exchange system for a high-temperature PEM fuel cell stack. This system integrates gas supply and heat exchange, using the high-temperature exhaust gas from the stack to preheat the reaction inlet gas. It employs pressurized gas supply and recovers the exhaust gas with residual pressure to reduce air compressor energy consumption. Furthermore, it designs a water condensation treatment scheme for the exhaust gas and a temperature and pressure control scheme for the inlet gas. This design facilitates a reliable reaction gas supply to the high-temperature PEM fuel cell stack and maximizes the system's energy utilization efficiency. Summary of the Invention

[0008] This invention proposes an integrated high-pressure gas supply and heat exchange system for a high-temperature PEM fuel cell stack. This system ensures stable operation of the high-temperature PEM fuel cell stack and improves the system's energy efficiency by recovering and utilizing waste heat and pressure from the exhaust gas, combined with precise control of the supply gas temperature and pressure. The system includes: a high-temperature PEM fuel cell stack, a temperature and pressure controlled heat exchanger, a condenser preheating heat exchanger, an air booster, temperature and pressure sensors, a heater, a flow regulating valve, and gas flow piping.

[0009] The high-temperature PEM fuel cell stack mentioned above refers to a PEM fuel cell stack with a high operating temperature, typically referring to a phosphoric acid-doped perfluorosulfonic acid membrane fuel cell, with an operating temperature usually in the range of 120-200℃. Its main function is to convert the chemical energy in hydrogen and air into electrical energy, accompanied by water and heat as byproducts.

[0010] The aforementioned temperature and pressure controlled heat exchanger is used for temperature and pressure control of the reaction gas, employing exhaust gas generated by the fuel cell stack and an internal heater to heat the inlet gas. Furthermore, the heat exchanger must be able to regulate the reactor inlet gas to maintain the required temperature and pressure. Specific temperature and pressure control can be achieved through comprehensive adjustment of the internal heater switch, inlet air pressure and temperature, and inlet air volume.

[0011] The aforementioned condenser preheating heat exchanger is used to condense water vapor in the exhaust gas and recover heat from the exhaust gas for preheating hydrogen and fresh air, thereby improving system energy efficiency. Condensate is discharged through a drain valve, reducing moisture interference during the exhaust gas recovery process.

[0012] The air booster is used to boost and recover exhaust gas, or to boost fresh air to the required pressure and supply it to the temperature and pressure controlled heat exchanger, and finally send it into the battery stack.

[0013] The temperature and pressure sensors are installed inside the temperature and pressure control heat exchanger to monitor the temperature and pressure of the intake air in real time, providing data support for system regulation.

[0014] The heater is placed in the gas path of the temperature and pressure controlled heat exchanger. When the exhaust gas is insufficient, the heater is automatically activated to ensure that the gas temperature entering the battery stack is stable.

[0015] The flow control valve is used to adjust the amount of exhaust gas recovery and the amount of fresh air mixing, so as to achieve precise airflow control and ensure that the system can flexibly adjust the airflow, temperature and pressure when the load changes.

[0016] The aforementioned gas flow pipeline is a pipeline through which hydrogen, air supply, and air exhaust flow pass, and is used for the circulation and heat exchange of various gases.

[0017] This invention integrates gas supply and heat exchange to recover and utilize waste heat and pressure from exhaust gas. It designs a high-pressure gas supply and heat exchange system for high-temperature PEM fuel cell stacks, which facilitates a reliable supply of reactant gas to the high-temperature PEM fuel cell stacks and maximizes the system's energy utilization efficiency. Attached Figure Description

[0018] Figure 1 Example of a combined supercharging system solution.

[0019] Figure 2 Example of a combined pressurization device scheme.

[0020] Figure 3 Example of a split-flow booster system solution.

[0021] Figure 4 Example of a flow diversion and booster device scheme.

[0022] In the diagram: 1-High-temperature PEM fuel cell stack, 2-Temperature and pressure controlled heat exchanger, 3-Condensing preheating heat exchanger, 4-Air booster, 5-Air booster, 6-Air booster, 7-Three-way flow control valve, 8-Two-way flow control valve, 9-Drain valve, 10-Heater, 11-Temperature sensor, 12-Pressure sensor, 13-Air pipe, 14-Hydrogen inlet, 15-Hydrogen pipe, 16-Air exhaust outlet, 17-Fresh air inlet, 18-Fresh air manifold, 19-Air exhaust branch outlet, A-Air exhaust passage, B-Air supply passage, C-Hydrogen passage. Detailed Implementation

[0023] Preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. This description is merely illustrative of the technical content of the present invention and does not constitute a limitation on its scope of protection.

[0024] The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system of the present invention mainly includes the following key components: high-temperature PEM fuel cell stack gas supply chamber (1), temperature and pressure controlled heat exchanger (2), condenser preheating heat exchanger (3), air booster (4-6), temperature sensor (11), pressure sensor (12), heater (10), flow regulating valve (7, 8), and airflow duct (13, 15). The airflow duct (13, 15) and inlet / outlet ports (14, 16, 17, 18, 19) within the system connect and run through each component. According to the design concept of the present invention, the system can adopt either combined pressurization or split pressurization as needed. Specific implementation schemes are as follows:

[0025] 1. Combined supercharging scheme (see appendix) Figure 1 and 2 )

[0026] Combined pressurization refers to the pressurization of exhaust gas recovery and fresh air supply to the required supply pressure after merging. In combined pressurization mode, exhaust gas with high temperature waste heat and waste pressure is discharged from the high temperature PEM fuel cell stack (1) and flows into the temperature and pressure controlled heat exchanger (2). In this heat exchanger, the exhaust gas exchanges heat with the air and hydrogen that are about to enter the stack, heating the reaction gases. After heat exchange, the exhaust gas continues to flow into the condenser preheating heat exchanger (3), where the exhaust gas exchanges heat with low temperature hydrogen and fresh air, achieving preheating of hydrogen and fresh air.

[0027] Inside the condenser preheating heat exchanger (3), water vapor in the air condenses, and the condensate is discharged through the drain valve (9). The preheated fresh air, along with some exhaust gas, enters the air booster (4), and after being pressurized, it is sent to the temperature and pressure controlled heat exchanger (2). Inside the temperature and pressure controlled heat exchanger, the pressurized air works together with the heat provided by the fuel cell exhaust gas or the heater (10) to ensure that the intake air reaches the required temperature and pressure.

[0028] In the system, as the load changes, the required gas supply and exhaust gas emissions of the battery stack will also change accordingly. These changes will affect the temperature and pressure inside the temperature and pressure controlled heat exchanger (2). At this time, through the feedback of the temperature sensor (11) and the pressure sensor (12), the system can automatically adjust the temperature and pressure through the heater and flow control valve to ensure a stable airflow supply.

[0029] In the temperature and pressure controlled heat exchanger (2), the filling gas in the chamber is pressurized air, and the exhaust gas and supplied hydrogen gas pass through the temperature and pressure controlled heat exchanger (2) in the air and hydrogen gas pipes to achieve heat exchange with the pressurized air. The specific number and shape of the pipes can be adjusted according to the requirements.

[0030] The condenser preheating heat exchanger (3) is mainly divided into three areas: a hydrogen preheating zone, a fresh air preheating zone, and a vapor-water separation zone. The hydrogen preheating zone is filled with hydrogen gas for preheating the hydrogen; the fresh air preheating zone is filled with fresh air for preheating the intake air; and the vapor-water separation zone is mainly used to separate and discharge condensate. The exhaust gas passes through the hydrogen preheating zone and the fresh air preheating zone via pipes, transferring heat to the hydrogen and fresh air during the heat exchange process, and finally discharging the condensate into the vapor-water separation zone.

[0031] The flow control valve is located at the fresh air inlet (18) and the exhaust gas outlet (16). The amount of fresh air mixed in and the amount of exhaust gas recovered can be flexibly adjusted according to needs.

[0032] The pressure control can be achieved by adjusting the power of the air booster, the amount of fresh air intake, and the amount of air exhaust gas recovery. When the gas supply demand increases, the gas pressure in the temperature and pressure controlled heat exchanger (2) will decrease due to the large amount of gas supplied. At this time, the amount of exhaust gas recovery and the amount of fresh air intake can be increased to achieve a larger gas supply. Conversely, when the gas supply demand decreases, the gas pressure in the temperature and pressure controlled heat exchanger (2) will increase, which can reduce the amount of air exhaust gas recovery and the supply of fresh air.

[0033] The temperature control is achieved by adjusting the fresh air ratio, the exhaust gas recovery amount, and the start / stop of the heater. When the temperature is too low, the heater (10) is started and the fresh air ratio is appropriately reduced; when the temperature is too high, the heater (10) is stopped and the fresh air ratio is increased.

[0034] 2. Flow split boosting scheme (see appendix) Figure 3 and 4 )

[0035] Split-flow pressurization refers to the separate pressurization of recovered exhaust gas and fresh air supply. In split-flow pressurization mode, part of the exhaust gas is directly pressurized by the air compressor (5) and enters the temperature and pressure controlled heat exchanger (2), while the other part flows through the temperature and pressure controlled heat exchanger (2) and the condenser preheating heat exchanger (3) through pipelines, exchanges heat with low-temperature hydrogen and fresh air, and is then discharged into the atmosphere. In this process, the recovered exhaust gas and fresh air are pressurized separately and sent to the temperature and pressure controlled heat exchanger (2), and then heated by the heater or fuel cell stack exhaust gas to ensure that the intake air reaches the set temperature and pressure. By adjusting the return ratio of the exhaust gas and the intake volume of fresh air, the system temperature and pressure can be flexibly controlled.

[0036] In the temperature and pressure controlled heat exchanger (2), the filling gas in the chamber is a mixture of pressurized recovered air tail gas and pressurized preheated fresh air. The unrecovered air tail gas and the supplied hydrogen gas pass through the temperature and pressure controlled heat exchanger (2) in the air and hydrogen gas pipes to achieve heat exchange. The specific number and shape of the pipes can be adjusted according to the requirements.

[0037] The condenser preheating heat exchanger (3) is mainly divided into two areas: a hydrogen and fresh air preheating area and a steam-water separation area. The hydrogen and fresh air preheating area is filled with hydrogen gas, and the pipes contain exhaust gas and pressurized fresh air, respectively. The steam-water separation area is for exhaust gas from the exhaust gas.

[0038] The temperature sensor (11) and pressure sensor (12) are located inside the temperature and pressure controlled heat exchanger (2) and are used to monitor the temperature and pressure near the gas supply port.

[0039] The flow control valve is located at the fresh air inlet (17) and the exhaust gas diversion port (19). The amount of fresh air mixed in and the amount of exhaust gas recovered can be flexibly adjusted according to needs.

[0040] The pressure control can be achieved by adjusting the power of the air booster, the amount of fresh air intake, and the amount of air exhaust recovery. When the demand for gas increases, the supply of a large amount of gas will reduce the gas pressure in the temperature and pressure controlled heat exchanger (2), at which point the fresh air intake can be increased to achieve a greater gas supply. Conversely, when the demand for gas decreases, the gas pressure in the temperature and pressure controlled heat exchanger (2) will increase, which can reduce the amount of air exhaust recovery and the supply of fresh air.

[0041] The temperature control can be achieved by adjusting the amount of fresh air entering the system, the amount of air exhaust recovered, and the start / stop of the heater (10) inside the temperature and pressure control heat exchanger (2). When the temperature is too low, the heater (10) can be started, and the proportion of fresh air in the supply can be appropriately reduced. When the temperature is too high, the heater (10) stops working, and the proportion of fresh air in the supply increases.

[0042] Summarize

[0043] This invention presents a highly efficient and reliable high-pressure gas supply and heat exchange system for high-temperature PEM fuel cell stacks, integrating heat exchange and gas supply with the recovery and utilization of waste heat and pressure from exhaust gas. Through precise temperature, pressure, and flow control, this system ensures stable operation of the high-temperature PEM fuel cell stack, improves system energy efficiency, and meets the demands under different loads and gas supply conditions.

Claims

1. A high-pressure gas supply and heat exchange system for a high-temperature PEM fuel cell stack, characterized in that, The system includes: a high-temperature PEM fuel cell stack (1), a temperature and pressure controlled heat exchanger (2), a condenser preheating heat exchanger (3), an air booster (4-6), a temperature sensor (11) and a pressure sensor (12), a heater (10), flow control valves (7, 8) and airflow ducts (13, 15).

2. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to claim 1, characterized in that, The temperature and pressure controlled heat exchanger (2) has functions such as heat exchange, inlet temperature monitoring and control, and inlet pressure monitoring and control.

3. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to claims 1 and 2, characterized in that, The temperature and pressure controlled heat exchanger (2) recovers part of the heat from the air exhaust through the heat exchange process between the exhaust air and the newly introduced air and hydrogen.

4. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to claim 1, characterized in that, The condenser preheating heat exchanger (3) includes hydrogen preheating, fresh air preheating and steam-water separation functions. The heat for preheating comes from the exhaust gas, and the heat of the exhaust gas can be further recovered and utilized.

5. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to claim 1, characterized in that, The flow control valves (7, 8) are used to regulate the intake volume of fresh air and the recovery volume of exhaust air.

6. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to claim 1, characterized in that, The temperature sensor (11) and pressure sensor (12) are located inside the temperature and pressure control heat exchanger (2) and are used to monitor the temperature and pressure of the intake air in real time.

7. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to claim 1, characterized in that, The temperature and pressure controlled heat exchanger (2) works in conjunction with the air booster (4-6), flow control valve (7, 8), and heater (10) to adjust the intake flow, temperature, and pressure based on the real-time temperature and pressure sensor data (11, 12).

8. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to any one of claims 1 to 7, characterized in that, The system can adjust the intake air flow, temperature and pressure in real time through an intelligent control unit, and dynamically optimize the system operation according to changes in load and environmental conditions, thereby achieving automatic optimization of energy management.

9. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to any one of claims 1 to 8, characterized in that, The system includes an exhaust gas residual pressure recovery system, which recovers and reuses a portion of the exhaust gas through a booster compressor to reduce energy consumption and improve system efficiency. The recovery system includes a booster compressor, a dynamic adjustment function, and a pressure sensor for automatically adjusting the recovery ratio, flow rate, and pressure.

10. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to claims 1 and 9, characterized in that, The system employs either a combined pressurization or a separate pressurization mode. Combined pressurization refers to condensing the exhaust air and mixing it with fresh air before pressurization, while separate pressurization refers to pressurizing the exhaust air and fresh air separately before mixing them.

11. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to any one of claims 1 to 10, characterized in that, The system incorporates a heat recovery system to preheat the intake air and hydrogen by using the waste heat generated by the fuel cell stack. It also improves heat exchange efficiency through a multi-stage heat exchange design, thereby achieving efficient heat recovery and reducing system energy consumption.

12. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to any one of claims 1 to 11, characterized in that, The system supports flexible configuration and can adjust the component configuration according to the capacity requirements of the fuel cell stack, supporting a variety of application scenarios from small to large fuel cell stacks.

13. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to any one of claims 1 to 12, characterized in that, The exhaust gas residual pressure recovery device can effectively remove the water produced by the reaction by introducing a condensate separation system.

14. The high-temperature PEM fuel cell stack high-pressure gas supply and heat exchange system according to any one of claims 1 to 13, characterized in that, The system organically integrates heat exchange and exhaust gas pressure recovery. The pressurization and heat exchange systems share most of the flow channels, simplifying the system complexity; the heat exchange process also helps to avoid water condensation during the mixing of new and old air. By adjusting the amount of recovered air and the amount of fresh air, temperature and pressure can be jointly controlled.

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