Fuel cell cross-temperature-zone operation control system and method
By monitoring the output performance of the fuel cell stack and adjusting the oxygen-to-air mixing ratio and power consumption, the problem of performance instability of fuel cells during cross-temperature operation was solved, and stable output performance was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NORTH CHINA ELECTRIC POWER UNIV
- Filing Date
- 2024-08-08
- Publication Date
- 2026-07-14
AI Technical Summary
When fuel cells operate across temperature zones, temperature changes lead to oxygen concentration dilution and alterations in catalytic reaction kinetics, resulting in performance degradation and unstable output.
The output performance of the fuel cell stack is monitored by a performance monitoring component. The controller adjusts the oxygen-air mixing ratio according to the preset rated performance and uses the mixing component and auxiliary power consumption component for feedback regulation to ensure the performance stability of the fuel cell across temperature ranges.
It achieves stable performance output of fuel cells during operation across temperature ranges, avoiding fluctuations in performance that are too high or too low, and ensuring normal operation of the battery.
Smart Images
Figure CN119009032B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of fuel cells, and in particular to a control system and method for fuel cell operation across temperature zones. Background Technology
[0002] Proton exchange membrane fuel cells (PEMFCs) are devices that directly convert chemical energy into electrical energy, with water as the only byproduct. They feature low start-up temperature, fast response speed, simple stack structure, and high power density, and are not limited by the Carnot cycle problem. In recent years, with the expansion of fuel cell applications and the increasing power of systems, the exothermic reaction inside the cell has intensified. To ensure normal operation, the requirements for fuel cell thermal management have become more stringent, and the adaptability of fuel cells to temperature fluctuations has been significantly enhanced.
[0003] One problem caused by increased operating temperature in fuel cells is intensified water vaporization, leading to dilution of oxygen in the air and resulting in performance degradation. Specifically, when a fuel cell operates across temperature zones, temperature changes cause variations in the saturated vapor pressure inside the fuel cell or stack cavity. Increased temperature intensifies water vaporization during the battery reaction, diluting the oxygen concentration within the cell and thus exhibiting performance degradation at high temperatures. Furthermore, excessive cooling of the battery, resulting in excessively low temperatures, slows down the catalytic reaction kinetics, also causing a decrease in output performance. In summary, both excessively high and excessively low temperatures cause fluctuations in performance output, impacting practical applications. Summary of the Invention
[0004] The purpose of this application is to provide a control system and method for cross-temperature zone operation of fuel cells, which can ensure the stable output of fuel cell stacks.
[0005] To achieve the above objectives, this application provides the following solution:
[0006] In a first aspect, this application provides a fuel cell cross-temperature zone operation control system, including a controller, a mixing component, a performance monitoring component, and an auxiliary power consumption component;
[0007] The performance monitoring component is connected to the target fuel cell stack, and the performance monitoring component is used to monitor the output performance of the target fuel cell stack at any time during cross-temperature zone operation.
[0008] The controller is connected to the performance monitoring component, and the controller is used to: receive the output performance; determine an adjustment instruction based on the change between the preset rated operating performance and the output performance; the adjustment instruction is a first adjustment instruction or a second adjustment instruction; the first adjustment instruction is used to improve the output performance of the target fuel cell stack during cross-temperature zone operation; the second adjustment instruction is used to reduce the output performance of the target fuel cell stack during cross-temperature zone operation.
[0009] The gas mixing assembly is connected to the controller and is also connected to the target fuel cell stack. The gas mixing assembly is used to: change the mixing ratio of oxygen and air input to the target fuel cell stack according to the first adjustment command.
[0010] The auxiliary power consumption component is connected to the controller, and the auxiliary power consumption component is used to consume the electrical energy generated by the target fuel cell stack according to the second adjustment command.
[0011] Optionally, the controller determines an adjustment command based on the change between the preset rated operating performance and the output performance, specifically by executing the following steps:
[0012] When the change between the preset rated operating performance and the output performance represents a decrease in the performance of the target fuel cell stack, an adjustment command is determined as the first adjustment command. The first adjustment command improves the output performance of the target fuel cell stack during cross-temperature zone operation by increasing the mixing ratio of oxygen and air input to the target fuel cell stack.
[0013] When the change between the preset rated operating performance and the output performance represents an increase in the performance of the target fuel cell stack, the adjustment command is determined to be the second adjustment command.
[0014] Optionally, the output performance of the target fuel cell stack during operation across temperature zones is characterized by output voltage, output current, or output power.
[0015] Optionally, the gas mixing assembly includes an oxygen source, an air compressor, and mixing components;
[0016] The first input terminal of the mixing component is connected to the output terminal of the oxygen source, and the second input terminal of the mixing component is connected to the output terminal of the air compressor; the output terminal of the mixing component is connected to the first input terminal of the target fuel cell stack.
[0017] The mixing component is used to: receive the compressed air output from the air compressor and the pure oxygen output from the oxygen source, and change the mixing ratio of oxygen and air input to the target fuel cell stack according to the first adjustment command.
[0018] Optionally, the fuel cell cross-temperature zone operation control system further includes two gas humidifiers and a hydrogen source;
[0019] The output end of the hydrogen source is connected to the second input end of the target fuel cell stack;
[0020] The two gas humidifiers are respectively disposed between the mixing component and the target fuel cell stack, and between the hydrogen source and the target fuel cell stack;
[0021] The gas humidifier is used to humidify the oxygen-enriched air or hydrogen entering the target fuel cell stack.
[0022] Optionally, the target fuel cell stack has a cross-temperature operating temperature range of 60°C to 120°C.
[0023] Secondly, this application provides a fuel cell cross-temperature zone operation control method, applied to the aforementioned fuel cell cross-temperature zone operation control system, the method comprising:
[0024] The performance monitoring components are used to monitor the output performance of the target fuel cell stack at any point during operation across temperature zones.
[0025] The controller determines an adjustment command based on the change between the preset rated operating performance and the output performance; the adjustment command is either a first adjustment command or a second adjustment command; the first adjustment command is used to improve the output performance of the target fuel cell stack during cross-temperature zone operation; the second adjustment command is used to reduce the output performance of the target fuel cell stack during cross-temperature zone operation.
[0026] The mixing component changes the mixing ratio of oxygen and air input to the target fuel cell stack according to the first adjustment command;
[0027] An auxiliary power-consuming component is used to consume the electrical energy generated by the target fuel cell stack according to the second adjustment command.
[0028] Optionally, the controller determines the adjustment command based on the change between the preset rated operating performance and the output performance, specifically including:
[0029] Using the controller, when the change between the preset rated operating performance and the output performance represents a decrease in the performance of the target fuel cell stack, an adjustment command is determined as the first adjustment command; the first adjustment command improves the output performance of the target fuel cell stack during cross-temperature zone operation by increasing the mixing ratio of oxygen and air input to the target fuel cell stack.
[0030] Using the controller, when the change between the preset rated operating performance and the output performance represents an increase in the performance of the target fuel cell stack, the adjustment command is determined as the second adjustment command.
[0031] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a fuel cell cross-temperature zone operation control system and method. A performance monitoring component monitors the output performance of the target fuel cell stack at any moment during cross-temperature zone operation, and determines the current performance state based on a preset rated operating performance. If the current performance state is poor, it needs to be improved. In this case, a first adjustment command is used to change the mixing ratio of oxygen and air input to the target fuel cell stack through a mixing component to compensate for the performance reduction. If the current performance state has improved, it needs to be reduced accordingly. In this case, a second adjustment command is used to consume power through an auxiliary power-consuming component. Finally, by performing the above-mentioned monitoring and adjustment on the output performance at any moment, the stable output performance of the target fuel cell stack during cross-temperature zone operation can be guaranteed, ensuring that it is neither too high nor too low. Attached Figure Description
[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0033] Figure 1 This is a schematic diagram of the structure of a fuel cell cross-temperature zone operation control system provided in an embodiment of this application;
[0034] Figure 2 A schematic flowchart of a fuel cell cross-temperature zone operation control method provided in an embodiment of this application;
[0035] Figure 3(a) shows the IV curves of the fuel cell stack at different operating temperatures; Figure 3(b) shows the IV curves at 0.4 A / cm. 2 DRT plots at different temperatures under different current densities; Figure 3(c) shows the current density at 1.0 A / cm². 2 DRT plots at different temperatures under different current densities.
[0036] Figure label:
[0037] 1-Controller, 2-Performance monitoring component, 3-Auxiliary power consumption component, 4-Target fuel cell stack, 5-Oxygen source, 6-Air compressor, 7-Mixing component, 8-Hydrogen source, 9-Gas humidifier. Detailed Implementation
[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0039] To address the performance fluctuation issue caused by changes in fuel cell operating temperature, this application monitors and controls the mixing of pure oxygen and air in a certain proportion to obtain oxygen-enriched air based on performance change feedback. This stabilizes the output performance of the fuel cell stack by increasing the oxygen concentration at the stack cathode. Simultaneously, if the rated operating temperature is not the optimal temperature for maximum output performance, the performance increase caused by temperature changes is consumed by the auxiliary power consumption system, thus ensuring stable output performance.
[0040] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0041] In one exemplary embodiment, this application provides a fuel cell cross-temperature zone operation control system, including a controller 1, a mixing assembly, a performance monitoring assembly 2, and an auxiliary power consumption assembly 3; specifically as follows: Figure 1 As shown, controller 1 can be represented by a host computer.
[0042] The performance monitoring component 2 is connected to the target fuel cell stack 4. The performance monitoring component 2 is used to monitor the output performance of the target fuel cell stack 4 at any given time during cross-temperature zone operation. In specific applications, the cross-temperature zone operating temperature range of the target fuel cell stack 4 is 60℃-120℃. The output performance of the target fuel cell stack 4 during cross-temperature zone operation is characterized by output voltage, output current, or output power. The corresponding performance monitoring component 2 may include components such as ammeters and voltmeters, which are determined by relevant technical personnel according to the requirements of the fuel cell stack in a specific application environment.
[0043] The controller 1 is connected to the performance monitoring component 2. The controller 1 is used to: receive the output performance; determine an adjustment command based on the change between the preset rated operating performance and the output performance; the adjustment command is a first adjustment command or a second adjustment command; the first adjustment command is used to improve the output performance of the target fuel cell stack 4 during cross-temperature zone operation; the second adjustment command is used to reduce the output performance of the target fuel cell stack 4 during cross-temperature zone operation. In other words, the controller 1 processes the signals from the performance monitoring component 2.
[0044] In a practical application, controller 1 determines adjustment instructions based on the change between the preset rated operating performance and the output performance. Specifically, controller 1 executes the following steps:
[0045] (1) When the change between the preset rated operating performance and the output performance represents a decrease in the performance of the target fuel cell stack 4, the adjustment command is determined as the first adjustment command; the first adjustment command improves the output performance of the target fuel cell stack 4 during cross-temperature zone operation by increasing the mixing ratio of oxygen and air input to the target fuel cell stack 4.
[0046] (2) When the change between the preset rated operating performance and the output performance represents the increase in the performance of the target fuel cell stack 4, the adjustment command is determined to be the second adjustment command.
[0047] To reflect actual conditions, a threshold can be set. When the change between the preset rated operating performance and the output performance is within the threshold range, the performance is considered to be at the rated level. If the change is less than the lower limit of the threshold range, it indicates a performance decrease. If the change is greater than the upper limit of the threshold range, it indicates a performance increase.
[0048] The gas mixing assembly is connected to the controller and also to the target fuel cell stack 4. The gas mixing assembly is used to change the mixing ratio of oxygen and air input to the target fuel cell stack 4 according to the first adjustment command. Specifically, a rise or fall in the temperature of the target fuel cell stack 4 will cause its performance to deviate, such as being higher or lower than its rated output performance. Whether it is higher or lower than the rated output performance is determined in the controller 1 based on the difference between the preset rated operating performance and the output performance. When the performance of the target fuel cell stack 4 is lower than the rated output performance at the current moment, the controller 1 sends the finally determined feedback signal (i.e., the first adjustment command) to the gas mixing assembly to increase the proportion of oxygen mixed in, thereby restoring its rated output performance.
[0049] In one application example, the mixing assembly includes an oxygen source 5, an air compressor 6, and a mixing component 7; the first input terminal of the mixing component 7 is connected to the output terminal of the oxygen source 5, the second input terminal of the mixing component 7 is connected to the output terminal of the air compressor 6, and the output terminal of the mixing component 7 is connected to the first input terminal of the target fuel cell stack 4.
[0050] The mixing component 7 is used to: receive the air compressed by the air compressor 6 and the pure oxygen output by the oxygen source 5, and change the mixing ratio of oxygen and air input to the target fuel cell stack 4 according to the first adjustment command. The oxygen in the oxygen source 5 is pure oxygen produced by the "electro-hydrogen" conversion or pure oxygen obtained through other means.
[0051] Furthermore, when the mixing component 7 changes the oxygen-to-air mixing ratio input to the target fuel cell stack 4 according to the first adjustment command, it also needs to control the total amount of gas in the target fuel cell stack 4 to ensure it does not exceed a preset value. If, based on the first adjustment command, the oxygen-to-air mixing ratio is increased, and the output performance monitored at the next moment indicates that the performance of the target fuel cell stack 4 has reached its rated value, then the current oxygen-to-air mixing ratio is maintained. Conversely, if the output performance monitored at the next moment indicates that the performance of the target fuel cell stack 4 is still below its rated value, then the oxygen-to-air mixing ratio is further increased. This is a continuous feedback adjustment process until the rated value is reached.
[0052] In another application example, the fuel cell cross-temperature zone operation control system of this application further includes two gas humidifiers 9 and a hydrogen source 8; the output end of the hydrogen source 8 is connected to the second input end of the target fuel cell stack 4; the two gas humidifiers 9 are respectively disposed between the mixing component 7 and the target fuel cell stack 4, and between the hydrogen source 8 and the target fuel cell stack 4; the gas humidifiers 9 are used to humidify the oxygen-enriched air or hydrogen entering the target fuel cell stack 4.
[0053] The auxiliary power-consuming component 3 is connected to the controller 1. The auxiliary power-consuming component 3 is used to consume the electrical energy generated by the target fuel cell stack 4 according to the second adjustment command. Specifically, when the performance of the target fuel cell stack 4 at the current moment is higher than the rated output performance, the controller 1 sends the final determined feedback signal (i.e., the second adjustment command) to the auxiliary power-consuming component 3 to consume electrical energy and maintain the rated output performance. If, after consuming electrical energy based on the second adjustment command, the output performance monitored at the next moment indicates that the performance of the target fuel cell stack 4 has reached the rated level, then no further consumption is needed; conversely, if the output performance monitored at the next moment indicates that the performance of the target fuel cell stack 4 is still higher than the rated level, then it cannot be directly input to the power consumption end and needs to continue consuming electrical energy until the rated level is reached. This is also a continuous feedback adjustment process.
[0054] Based on the same inventive concept, this application also provides a fuel cell cross-temperature zone operation control method, which is applied to the above-mentioned fuel cell cross-temperature zone operation control system. The solution provided by this method is similar to the solution described in the above-mentioned system. Therefore, the specific limitations in the method embodiments provided below can be found in the system limitations above, and will not be repeated here.
[0055] In one exemplary embodiment, such as Figure 2As shown, this application also provides a method for controlling the operation of a fuel cell across temperature zones, including:
[0056] Step 100: Use a performance monitoring component to monitor the output performance of the target fuel cell stack at any time during operation across temperature zones.
[0057] Step 200: The controller determines an adjustment instruction based on the change between the preset rated operating performance and the output performance; the adjustment instruction is either a first adjustment instruction or a second adjustment instruction; the first adjustment instruction is used to improve the output performance of the target fuel cell stack during cross-temperature zone operation; the second adjustment instruction is used to reduce the output performance of the target fuel cell stack during cross-temperature zone operation.
[0058] Specifically, step 200 includes:
[0059] (1) Using the controller, when the change between the preset rated operating performance and the output performance represents the performance degradation of the target fuel cell stack, an adjustment instruction is determined as the first adjustment instruction; the first adjustment instruction improves the output performance of the target fuel cell stack during cross-temperature zone operation by increasing the mixing ratio of oxygen and air input to the target fuel cell stack.
[0060] (2) Using the controller, when the change between the preset rated operating performance and the output performance represents the increase in the performance of the target fuel cell stack, the adjustment command is determined as the second adjustment command.
[0061] Step 300: The mixing component changes the mixing ratio of oxygen and air input to the target fuel cell stack according to the first adjustment instruction.
[0062] Step 400: An auxiliary power-consuming component is used to consume the electrical energy generated by the target fuel cell stack according to the second adjustment instruction.
[0063] This application also provides an application embodiment to verify the practicality and feasibility of the fuel cell cross-temperature zone operation control system and method provided in this application. Figure 3(a) shows the IV curves of the fuel cell stack at different operating temperatures. As shown in Figure 3(a), the power density of the fuel cell stack first increases with increasing temperature, and then decreases after 80°C with further increasing temperature. The reason for the initial increase in performance (power) is that the increase in temperature increases the reaction kinetics, and the increased vaporization capacity reduces the content of some liquid water, weakens the blockage of pores by water, and optimizes oxygen mass transfer. The reason for the subsequent decrease in performance (power) is that with further increases in temperature, the saturated vapor pressure in the cell cavity increases, the degree of vaporization of generated water intensifies, and the oxygen partial pressure decreases under constant cell pressure, thus showing a serious performance degradation. Figures 3(b) and 3(c) show 0.4 A / cm 2 and 1.0A / cm 2 The DRT (relaxation time distribution) plots at two different current densities and temperatures, upon further analysis of the results in the above figure, reveal that the most significant change is observed in the P1 peak, whose intensity corresponds to the oxygen transport impedance. Specifically, as temperature increases, the oxygen mass transfer impedance first decreases and then increases. The decrease in oxygen mass transfer impedance with increasing temperature is due to the enhanced vaporization capacity reducing the liquid water content, thus mitigating water blockage of the pores and significantly optimizing oxygen mass transfer. The subsequent continuous increase in oxygen mass transfer impedance is caused by the increased dilution of oxygen concentration within the stack by the added gaseous water, which corresponds to the results of the IV analysis. Furthermore, the charge transport impedance corresponding to the P2 peak first decreases and then increases. The decrease is due to the increased catalytic reaction kinetics caused by the increased battery temperature, while the subsequent increase is due to the restricted ORR process caused by the limited gas mass transfer process, which also corresponds to the previous analysis.
[0064] Analysis of the three graphs in Figure 3 shows that the performance of the fuel cell stack is temperature-dependent. Both excessively high and low temperatures negatively impact performance, and this process is non-linear, requiring continuous adjustment to ensure stable output. Therefore, this application uses a host computer to compile the performance signals (power, voltage, or current) output by the fuel cell stack during cross-temperature range operation. These signals are then converted into electrical signals to control the flow rate of pure oxygen released by the mixing component. After mixing with air, the oxygen-enriched air is input into the fuel cell stack to compensate for performance degradation. Furthermore, if the rated operating temperature is not the optimal temperature for maximum output performance (the stack's output performance is the rated output voltage, rated output current, or rated output power at the rated temperature during normal operation), the performance increase caused by temperature changes is consumed by the auxiliary power consumption system, thus ensuring stable output performance.
[0065] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0066] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A fuel cell cross-temperature zone operation control system, characterized in that, The fuel cell cross-temperature zone operation control system includes a controller, a mixing assembly, a performance monitoring assembly, and an auxiliary power consumption assembly. The performance monitoring component is connected to the target fuel cell stack, and the performance monitoring component is used to monitor the output performance of the target fuel cell stack at any time during cross-temperature zone operation. The controller is connected to the performance monitoring component. The controller is configured to: receive the output performance; when the change between the preset rated operating performance and the output performance indicates a decrease in the performance of the target fuel cell stack, determine an adjustment instruction as a first adjustment instruction; the first adjustment instruction increases the oxygen-air mixing ratio input to the target fuel cell stack to improve the output performance of the target fuel cell stack during cross-temperature zone operation; when the change between the preset rated operating performance and the output performance indicates an increase in the performance of the target fuel cell stack, determine an adjustment instruction as a second adjustment instruction; the second adjustment instruction is used to reduce the output performance of the target fuel cell stack during cross-temperature zone operation. The gas mixing assembly is connected to the controller and is also connected to the target fuel cell stack. The gas mixing assembly includes an oxygen source, an air compressor, and a mixing component. The first input terminal of the mixing component is connected to the output terminal of the oxygen source, and the second input terminal of the mixing component is connected to the output terminal of the air compressor. The output terminal of the mixing component is connected to the first input terminal of the target fuel cell stack. The mixing component is used to: receive air compressed and output by the air compressor and pure oxygen output by the oxygen source, and change the mixing ratio of oxygen and air input to the target fuel cell stack according to the first adjustment command. The auxiliary power consumption component is connected to the controller, and the auxiliary power consumption component is used to consume the electrical energy generated by the target fuel cell stack according to the second adjustment command.
2. The fuel cell cross-temperature zone operation control system according to claim 1, characterized in that, The output performance of the target fuel cell stack during operation across temperature zones is characterized by output voltage, output current, or output power.
3. The fuel cell cross-temperature zone operation control system according to claim 1, characterized in that, The fuel cell cross-temperature zone operation control system also includes two gas humidifiers and a hydrogen source; The output end of the hydrogen source is connected to the second input end of the target fuel cell stack; The two gas humidifiers are respectively disposed between the mixing component and the target fuel cell stack, and between the hydrogen source and the target fuel cell stack; The gas humidifier is used to humidify the oxygen-enriched air or hydrogen entering the target fuel cell stack.
4. The fuel cell cross-temperature zone operation control system according to claim 1, characterized in that, The target fuel cell stack has a cross-temperature operating temperature range of 60℃-120℃.
5. A method for controlling cross-temperature zone operation of a fuel cell, applied to the cross-temperature zone operation control system of a fuel cell as described in any one of claims 1-4, characterized in that, The method for controlling cross-temperature zone operation of the fuel cell includes: The performance monitoring components are used to monitor the output performance of the target fuel cell stack at any point during operation across temperature zones. Using the controller, when the change between the preset rated operating performance and the output performance represents a decrease in the performance of the target fuel cell stack, an adjustment command is determined as the first adjustment command; the first adjustment command improves the output performance of the target fuel cell stack during cross-temperature zone operation by increasing the mixing ratio of oxygen and air input to the target fuel cell stack. Using the controller, when the change between the preset rated operating performance and the output performance represents an increase in the performance of the target fuel cell stack, an adjustment command is determined as a second adjustment command; the second adjustment command is used to reduce the output performance of the target fuel cell stack during cross-temperature zone operation. The mixing component changes the mixing ratio of oxygen and air input to the target fuel cell stack according to the first adjustment command; An auxiliary power-consuming component is used to consume the electrical energy generated by the target fuel cell stack according to the second adjustment command.