Fuel cell control system, fuel cell control method, and electrochemical detection apparatus

Abstract

A fuel cell control system, which includes an electrochemical detection apparatus, a control apparatus and a power converter, and is used for coupling a fuel cell to supply power to a load. The electrochemical detection apparatus includes a sensing apparatus and a processor. The sensing apparatus is used for sensing a cell current and a cell voltage. The processor is used for executing electrochemical analysis on the basis of the cell voltage and the cell current, and determining a water content state of the fuel cell. The control apparatus is used for adjusting a fuel state of the fuel cell when the water content state is a dry film state or a water-saturated state. The power converter is used for determining a load condition of the fuel cell, and generating output power on the basis of the cell voltage and the cell current when the water content state is in a normal state, wherein the cell voltage and the cell current are related to the load condition. The present disclosure further relates to a fuel cell control method and an electrochemical detection apparatus.

Description

Fuel cell control system, fuel cell control method and electrochemical detection device Technical Field

[0001] This disclosure relates to parameter control technology for fuel cell systems, and in particular to a fuel cell control system, fuel cell control method, and electrochemical detection device that can sense the water content state of the fuel cell and adjust related parameters. Background Technology

[0002] In current fuel cell technology, fuel cells generate electricity using fuel (i.e., reactant gases). Therefore, most commercially available fuel cell systems control the current by adjusting the amount of fuel. The performance of a fuel cell is related to its water content; when the water content is unbalanced, it will lead to a decrease in the fuel cell's output power and a shortened lifespan. To ensure proper operation, the fuel cell controls the fuel supply to maintain the water content of the membrane electrode assembly (membrane material) at a normal level.

[0003] Currently, commercially available fuel cells typically use voltage detectors to monitor the voltage of each fuel cell, thereby determining whether the water content of the fuel cell is unbalanced. However, this method cannot accurately determine the water content state of the fuel cell, thus affecting the efficiency of fuel adjustment. Therefore, how to efficiently adjust the fuel based on the water content state of the fuel cell in real time is one of the challenges in this field. Summary of the Invention

[0004] This disclosure provides a fuel cell control system. The fuel cell control system includes an electrochemical detection device, a control device, and a power converter for coupling to the fuel cell to supply power to a load. The electrochemical detection device, coupled to the fuel cell, includes a sensing device and a processor. The sensing device senses the cell current and cell voltage of the fuel cell. The processor, coupled to the sensing device, performs electrochemical analysis based on the cell voltage and cell current, and determines the water state of the fuel cell based on the electrochemical analysis. The control device, coupled to the fuel cell and the electrochemical detection device, adjusts the fuel state of the fuel cell when the water state is in a dry film state or a flooded state. The power converter determines the load conditions of the fuel cell and generates an output power supply based on the cell voltage and cell current when the water state of the fuel cell is in a normal state, wherein the cell voltage and cell current are related to the load conditions.

[0005] This disclosure provides a fuel cell control method applicable to fuel cell control systems. The fuel cell control method includes the following steps: determining the load conditions of the fuel cell via a power converter; generating battery voltage and battery current via the fuel cell based on the load conditions and the fuel state of the fuel cell; sensing the battery voltage and battery current via a sensing device; performing electrochemical analysis via a processor based on the battery voltage and battery current to determine the water content state of the fuel cell; adjusting the fuel state of the fuel cell via a control device in response to the fuel cell's water content state being in a dry membrane state or a flooded state; and generating output power via the power converter based on the battery voltage and battery current in response to the fuel cell's water content state being in a normal state.

[0006] This disclosure provides an electrochemical detection device coupled to a fuel cell. The electrochemical detection device includes a sensing device and a processor. The sensing device senses the cell current and cell voltage generated by the fuel cell according to the fuel state. The processor, coupled to the sensing device, performs electrochemical analysis based on the cell voltage and cell current, and determines, based on the electrochemical analysis, whether the water content state of the fuel cell is in a normal state, a dry film state, or a flooded state.

[0007] The fuel cell control system, fuel cell control method, and electrochemical detection device disclosed herein can determine whether the water content of the fuel cell is normal by using electrochemical analysis, and adjust the fuel state of the fuel cell based on the analysis results, thereby effectively avoiding an imbalance in the water content of the fuel cell. Attached Figure Description

[0008] To make the above and other objects, features, advantages and embodiments of this disclosure more apparent and understandable, the accompanying drawings are described below:

[0009] Figure 1 is a schematic diagram illustrating the change of cell voltage over time in a fuel cell, based on some examples.

[0010] Figure 2 is a functional block diagram of a fuel cell control system according to some embodiments of this disclosure;

[0011] Figure 3 is a functional block diagram of the fuel cell according to the embodiment shown in Figure 2;

[0012] Figure 4 shows the electrochemical impedance spectroscopy of a fuel cell according to some embodiments of this disclosure;

[0013] Figure 5 shows a high-frequency resistance spectrum of a fuel cell according to some embodiments of this disclosure;

[0014] Figure 6A is a flowchart illustrating a fuel cell control method according to some embodiments of this disclosure;

[0015] Figure 6B is a flowchart of some steps of a fuel cell control method according to some embodiments of this disclosure;

[0016] Figure 6C is a flowchart illustrating some steps of a fuel cell control method according to some embodiments of this disclosure; and

[0017] Figure 6D is a flowchart of some steps of a fuel cell control method according to some embodiments of this disclosure.

[0018] Figure reference numerals: 100: Fuel cell control system; 110: Fuel cell; 110_EIS: Electrochemical impedance spectroscopy; 110_HFR: High-frequency resistance spectrum; 111: Fuel cell stack; 112: Temperature control subsystem; 113: Air conditioning subsystem; 114: Hydrogen conditioning subsystem; 120: Electrochemical detection device; 121: Sensing device; 122: Processor; 130: Control device; 140: Power converter; 150: System load; 600: Fuel cell control method; S610, S620, S630, S640: Steps; S650, S660, S670, S680: Steps; S690: Steps; S690A, S690D, S690F: Steps; S690D1~S690D8: Steps; S690F1~S690F8: Steps; AD: Adjustment command; ANA: Analysis result. FC Battery current V FC Battery voltage Z': Real part of impedance Z”: Imaginary part of impedance Detailed Implementation

[0019] The embodiments of this disclosure will be described below with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or similar elements or method flows.

[0020] Unless otherwise specified in the text, “a” and “the” may refer to one or more. It will be further understood that the words “comprising,” “including,” “having,” and similar terms as used herein refer to the features, regions, integers, steps, operations, elements, and / or components described herein, but do not exclude one or more other features, regions, integers, steps, operations, elements, components, and / or groups thereof described or additionally described herein.

[0021] Figure 1 shows the cell voltage V of a fuel cell based on some examples. FC A schematic diagram illustrating the change over time. As shown in the upper part of Figure 1, the fuel cell voltage V changes as the fuel cell's usage time increases. FC and battery current I FCThe relationship between them will change. Specifically, as shown in the lower half of Figure 1, under the same battery current I... FC (For example, the battery current I corresponding to the vertical line in the upper half of Figure 1) FC Under the condition of ), the cell voltage V of the fuel cell FC The ability of a fuel cell to generate electricity will decrease over time.

[0022] While this undesirable degradation occurs in fuel cells over time, the rate of degradation can be slowed down through proper management of the state of water content (also known as "water management"). To effectively manage the state of water content in a fuel cell, this disclosure provides a fuel cell control system.

[0023] Figure 2 is a functional block diagram of a fuel cell control system 100 according to some embodiments of this disclosure. In some embodiments, the fuel cell control system 100 includes an electrochemical detection device 120, a control device 130, and a power converter 140 for supplying power to a system load 150 based on the fuel cell 110.

[0024] The fuel cell 110 is coupled to the electrochemical detection device 120, the control device 130, and the power converter 140 to generate a battery voltage V based on the load conditions set by the power converter 140 and the fuel state of the fuel cell 110. FC and battery current I FC In some embodiments, the fuel state of the fuel cell 110 includes the temperature state, air supply state, and hydrogen supply state of the fuel cell 110. Depending on the temperature state, air supply state, and hydrogen supply state, the fuel cell 110 will have different water contents, and thus be in different water content states.

[0025] Specifically, when the water content of the membrane electrode assembly in fuel cell 110 is below an ideal value, the water content state of fuel cell 110 is referred to as being in a "dry" state; when the water content of the membrane electrode assembly in fuel cell 110 is above this ideal value, the water content state of fuel cell 110 is referred to as being in a "flooding" state; and when the water content of the membrane electrode assembly in fuel cell 110 is equal to this ideal value, the water content state of fuel cell 110 is referred to as being in a "normal" state. The method for determining the water content of fuel cell 110 will be explained in detail in subsequent paragraphs.

[0026] In some embodiments, the fuel cell 110 includes a subsystem for controlling the aforementioned fuel state. Referring to FIG3, FIG3 is a functional block diagram of the fuel cell 110 according to the embodiment of FIG2. In some embodiments, the fuel cell 110 includes a fuel cell stack 111, a temperature control subsystem 112, an air conditioning subsystem 113, and a hydrogen regulation subsystem 114. The temperature control subsystem 112, the air conditioning subsystem 113, and the hydrogen regulation subsystem 114 are coupled to the fuel cell stack 111 to adjust the temperature state, air supply state, and hydrogen supply state of the fuel cell 110 respectively upon receiving a regulation command AD from the control device 130, so that the fuel cell 110 generates a corresponding battery voltage V. FC and battery current I FC .

[0027] Please refer to Figure 2 again. The electrochemical detection device 120 is coupled to the fuel cell 110, the control device 130, and the power converter 140 to perform electrochemical analysis on the fuel cell 110. In some embodiments, the electrochemical detection device 120 includes a sensing device 121 and a processor 122.

[0028] The sensing device 121 is coupled to the fuel cell 110 to sense the battery voltage V of the fuel cell 110. FC and battery current I FC It should be noted that although the sensing device 121 in FIG2 is shown as a single block, the sensing device 121 is not limited to being implemented using a single device. In some embodiments, the sensing device 121 can be implemented by a combination of two or more electronic devices with sensing functions (e.g., voltage detectors and current meters).

[0029] In some embodiments, the sensing device 121 may sense the battery voltage V of the fuel cell 110 once every preset inspection cycle (e.g., ten minutes). FC and battery current I FC This enables automated (also known as active) adjustment. In other embodiments, sensing device 121 may also sense the battery voltage V of fuel cell 110 upon receiving an adjustment command (e.g., from processor 122). FC and battery current I FC .

[0030] Processor 122 is coupled to sensing device 121 for processing based on the battery voltage V sensed by sensing device 121. FC and battery current I FC Perform electrochemical analysis and determine the water content state of fuel cell 110 based on the results of the electrochemical analysis.

[0031] In some embodiments, the electrochemical analysis performed by the processor 122 is performed by generating and analyzing an electrochemical impedance spectroscopy (EIS). Referring to Figure 4, Figure 4 shows an EIS of the electrochemical impedance spectroscopy 110 of a fuel cell 110 according to some embodiments of this disclosure, where the horizontal axis represents the real part Z' of the impedance of the fuel cell 110, and the vertical axis represents the imaginary part Z of the impedance of the fuel cell 110.

[0032] First, the processor 122 calculates the ideal electrochemical impedance spectroscopy (e.g., the curve labeled "normal state" in Figure 4) based on the load conditions set by the power converter 140, and then calculates the battery voltage V sensed by the sensing device 121. FC and battery current I FC The electrochemical impedance spectroscopy (EIS) spectrum was calculated. It should be noted that those skilled in the art will understand the methods for generating the "electrochemical impedance spectroscopy" mentioned in this disclosure, and for the sake of brevity, they will not be repeated here.

[0033] In some embodiments, the processor 122 can determine the current water content state of the fuel cell 110 by comparing an ideal electrochemical impedance spectroscopy (EIS) and measuring the surface area of ​​the EIS graph. When the surface area of ​​the EIS graph corresponding to the current water content state is greater than the surface area corresponding to the normal state, the processor 122 determines that the water content state of the fuel cell 110 is in a dry film state; when the surface area of ​​the EIS graph corresponding to the current water content state is less than the surface area corresponding to the normal state, the processor 122 determines that the water content state of the fuel cell 110 is in a flooded state.

[0034] In other embodiments, the processor 122 can determine the current water content state of the fuel cell 110 by comparing the ideal electrochemical impedance spectroscopy (EIS) with the peak value of the measured EIS. When the peak value in the EIS corresponding to the current water content state is greater than the peak value corresponding to the normal state, the processor 122 determines that the water content state of the fuel cell 110 is in the dry membrane state; when the peak value in the EIS corresponding to the current water content state is less than the peak value corresponding to the normal state, the processor 122 determines that the water content state of the fuel cell 110 is in the flooded state.

[0035] In some other embodiments, the processor 122 can determine the current water content state of the fuel cell 110 based on the trend of the graphical curve of the electrochemical impedance spectroscopy (EIS). When the graphical curve corresponding to the current water content state in the EIS of the EIS is a divergent curve, the processor 122 determines that the water content state of the fuel cell 110 is in a dry film state; when the graphical curve corresponding to the current water content state in the EIS of the EIS is a convergent curve, the processor 122 determines that the water content state of the fuel cell 110 is in a flooded state.

[0036] Furthermore, the processor 122 can also combine the aforementioned various judgment methods to determine the current water content status of the fuel cell 110. For example, the processor 122 can determine the water content status of the fuel cell 110 based on both the surface area and peak value of the electrochemical impedance spectroscopy.

[0037] It should be noted that the electrochemical analysis mentioned in this disclosure is not limited to generating electrochemical impedance spectroscopy. In some embodiments, the electrochemical analysis performed by processor 122 is performed by generating and analyzing high-frequency resistance (HFR) spectra. Please refer to Figure 5, which is a high-frequency resistance spectrum 110_HFR of fuel cell 110 according to some embodiments of this disclosure, where the vertical axis represents the resistance value of fuel cell 110.

[0038] First, the processor 122 calculates the ideal high-frequency resistance spectrum (e.g., the curve labeled "normal state" in Figure 5) based on the load conditions set by the power converter 140, and then calculates the battery voltage V sensed by the sensing device 121. FC and battery current I FC The high-frequency resistance spectrum is calculated. It should be noted that those skilled in the art should be able to understand the method for generating the "high-frequency resistance spectrum" mentioned in this disclosure, and for the sake of brevity, it will not be repeated here.

[0039] Next, the processor 122 can determine the current water content state of the fuel cell 110 by comparing the ideal high-frequency resistance spectrum with the measured high-frequency resistance spectrum. Under the same time conditions, when the resistance value of the curve corresponding to the current water content state in the high-frequency resistance spectrum 110_HFR is greater than the resistance value of the curve corresponding to the normal state, the processor 122 will determine that the water content state of the fuel cell 110 is in the dry membrane state; when the resistance value of the curve corresponding to the current water content state in the high-frequency resistance spectrum 110_HFR is less than the resistance value of the curve corresponding to the normal state, the processor 122 will determine that the water content state of the fuel cell 110 is in the flooded state.

[0040] Furthermore, in some embodiments, the processor 122 is further used to determine whether the system load of the fuel cell control system 100 is stable. When the system load of the fuel cell control system 100 is not yet stable, the processor 122 will wait for a specified time and then reconfirm whether the system load of the fuel cell control system 100 is stable; when the system load of the fuel cell control system 100 is stable, the processor 122 will perform the aforementioned electrochemical analysis.

[0041] Please refer to Figure 2 again. After the processor 122 completes the determination of the water content state of the fuel cell 110, it will transmit the analysis result ANA to the control device 130. The control device 130 is coupled to the fuel cell 110 and the electrochemical detection device 120, and is used to transmit the adjustment command AD to the fuel cell 110 to adjust the fuel state of the fuel cell 110 when the water content state of the fuel cell 110 is in the dry membrane state or the water flooding state.

[0042] Specifically, when the water content of the fuel cell 110 is in a dry membrane state, the control device 130 selects at least one of the following operations to perform: (by instructing the hydrogen regulation subsystem 114) increasing the hydrogen supply state of the fuel cell 110; (by instructing the hydrogen regulation subsystem 113) increasing the air supply state of the fuel cell 110; and (by instructing the temperature control subsystem 112) decreasing the temperature state of the fuel cell 110. In some embodiments, the operations of increasing the air supply state and decreasing the temperature state of the fuel cell 110 are given higher priority than the operation of increasing the hydrogen supply state of the fuel cell 110, in order to save the cost of regulation.

[0043] On the other hand, when the water content of the fuel cell 110 is in a flooded state, the control device 130 selects at least one of the following operations to perform: (by instructing the hydrogen regulation subsystem 114) reducing the hydrogen supply state of the fuel cell 110; (by instructing the hydrogen regulation subsystem 113) reducing the air supply state of the fuel cell 110; and (by instructing the temperature control subsystem 112) increasing the temperature state of the fuel cell 110. In some embodiments, the operations of reducing the air supply state of the fuel cell 110 and increasing the temperature state of the fuel cell 110 are given higher priority than the operation of reducing the hydrogen supply state of the fuel cell 110, in order to save the cost of regulation.

[0044] After the control device 130 adjusts the fuel state of the fuel cell 110, the electrochemical detection device 120 will again sense the battery voltage V of the fuel cell 110. FC and battery current I FCThe adjustment process is repeated until the water content of the fuel cell 110 returns to normal. Through this control method, the fuel cell control system 100 of this disclosure can achieve the "closed-loop" characteristic of the system.

[0045] The power converter 140 is coupled to the fuel cell 110 and the system load 150 to determine the load conditions of the fuel cell 110 and apply these load conditions to the system load 150. When the water content of the fuel cell 110 returns to normal, the power converter 140 adjusts the power according to the current battery voltage V. FC and battery current I FC This generates a corresponding output power. In some embodiments, the fuel cell 110 generates a battery voltage V. FC and battery current I FC Relevant to the current load conditions.

[0046] In some embodiments, the power converter 140 may be implemented by a DC-DC converter, a DC-AC converter, other devices with conversion functions, or any combination thereof.

[0047] In some embodiments, the electrochemical detection device 120 and the power converter 140 may be respectively disposed on different substrates in the fuel cell control system 100 and connected to each other via a specific transmission method (e.g., via a universal asynchronous receiver / transmitter, UART) to transmit signals to each other. In some embodiments not shown, the electrochemical detection device 120 and the power converter 140 may also be integrated into a single electronic device, with the electrochemical detection device 120 disposed at the front end of this electronic device.

[0048] Figure 6A is a flowchart illustrating a fuel cell control method 600 according to some embodiments of this disclosure. The fuel cell control method 600 is applicable to a fuel cell control system (e.g., the fuel cell control system of Figure 2). In some embodiments, the fuel cell control method 600 includes steps S610, S620, S630, S640, S650, S660, S670, S680, and S690.

[0049] In step S610, the load conditions of the fuel cell (e.g., fuel cell 110) are determined by a power converter (e.g., power converter 140). Then, step S620 is executed.

[0050] In step S620, the fuel cell generates battery voltage and battery current based on load conditions and the fuel state of the fuel cell. Next, step S630 is executed.

[0051] In step S630, the battery voltage and battery current generated by the fuel cell are sensed by a sensing device (e.g., sensing device 121). Then, step S640 is executed.

[0052] In step S640, the processor (e.g., processor 122) determines whether the system load of the fuel cell control system has stabilized. If the system load of the fuel cell control system has not yet stabilized, step S650 is executed; if the system load of the fuel cell control system has stabilized, step S660 is executed.

[0053] In step S650, the processor is in standby mode for a specified time, and after the standby is completed, step S640 is executed again to reconfirm whether the system load of the fuel cell control system has stabilized.

[0054] In step S660, since the processor determines that the system load of the fuel cell control system has stabilized, it performs electrochemical analysis based on the battery voltage and current to determine the water content state of the fuel cell. Next, step S670 is executed.

[0055] In step S670, the processor determines whether the water content of the fuel cell is in a normal state. If the water content is in a normal state, step S680 is executed; if the water content is not in a normal state (i.e., in a dry membrane state or a flooded state), step S690 is executed.

[0056] In step S680, the power converter generates output power based on the battery voltage and battery current.

[0057] In step S690, the fuel state of the fuel cell is adjusted by a control device (e.g., control device 130), and after the adjustment is completed, step S660 is executed again to determine the water content state of the fuel cell after adjustment.

[0058] As mentioned above, the control circuit adjusts the fuel state of the fuel cell in different ways depending on whether the water content is in a dry membrane state or a flooded state. Therefore, in some embodiments, step S690 further includes more steps. Please refer to Figure 6B, which is a flowchart of step S690 of a fuel cell control method 600 according to some embodiments of this disclosure. In some embodiments, step S690 includes steps S690A, S690D, and S690F.

[0059] Step S690A follows step S670. In step S690A, the processor determines whether the water content state of the fuel cell is in a dry membrane state or a flooded state. If the water content state of the fuel cell is in a dry membrane state, step S690D is executed; if the water content state of the fuel cell is in a flooded state, step S690F is executed.

[0060] For a detailed flowchart of step S690D, please refer to Figure 6C. Figure 6C is a flowchart of step S690D of a fuel cell control method 600 according to some embodiments of this disclosure. In step S690D, the fuel state of the fuel cell is adjusted for the dry membrane state by a control device, and in some embodiments, step S690D includes steps S690D1 to S690D8.

[0061] In step S690D1, the temperature state of the fuel cell is reduced by the control device, and then step S690D2 is executed. In step S690D2, it is determined whether the dry membrane state has been released. If the dry membrane state has been released, step S690D3 is executed; if the dry membrane state has not been released, step S690D4 is executed.

[0062] In step S690D3, since the dry membrane state has been released, the control device has completed the adjustment of the fuel state of the fuel cell and maintained the fuel cell at the current fuel state (i.e., temperature state, air supply state, hydrogen supply state).

[0063] In step S690D4, since adjusting the temperature still fails to resolve the dry membrane state, the control device then increases the air supply to the fuel cell and proceeds to step S690D5. In step S690D5, it is determined whether the dry membrane state has been resolved. If the dry membrane state has been resolved, step S690D3 is then executed; if the dry membrane state has not been resolved, step S690D6 is then executed.

[0064] In step S690D6, since adjusting the air supply status still fails to resolve the dry membrane state, the control device then increases the hydrogen supply status of the fuel cell and proceeds to step S690D7. In step S690D7, it is determined whether the dry membrane state has been resolved. If the dry membrane state has been resolved, step S690D3 is then executed; if the dry membrane state has not been resolved, step S690D8 is then executed.

[0065] In step S690D8, since adjusting the temperature state, air supply state, and hydrogen supply state with the current adjustment range cannot relieve the dry membrane state, the control device will increase the adjustment range and execute step S690D1 again to adjust the fuel state of the fuel cell using the new adjustment range.

[0066] On the other hand, for a detailed flowchart of step S690F, please refer further to Figure 6D. Figure 6D is a flowchart of step S690F of a fuel cell control method 600 according to some embodiments of this disclosure. In step S690F, the fuel state of the fuel cell is adjusted by a control device for a flooded state, and in some embodiments, step S690F includes steps S690F1 to S690F8.

[0067] Steps S690F1 to S690F8 in Figure 6D are similar to steps S690D1 to S690D8 in Figure 6C. For the sake of brevity, the following paragraphs will only focus on describing the differences between steps S690F1 to S690F8 and steps S690D1 to S690D8, while their similarities will not be repeated here.

[0068] Specifically, since steps S690F1 to S690F8 are for adjusting the fuel state of the fuel cell in the case of water flooding, the adjustment directions of steps S690F1, S690F4, and S690F6 will be opposite to those of steps S690D1, S690D4, and S690D6 (i.e., increasing the temperature state, decreasing the air supply state, and decreasing the hydrogen supply state), while steps S690F2, S690F5, and S690F7 are for determining whether the water flooding state has been eliminated.

[0069] It should be noted that the number and order of steps in the flowcharts of Figures 6C and 6D are merely examples and are not intended to limit this disclosure. The number and order of other steps are within the scope of this disclosure. In some embodiments, steps S690D1 and S690D4 can be interchanged, and steps S690F1 and S690F4 can be interchanged. In some embodiments, an additional step may be included between steps S690D1 and S690D2 (steps S690F1 and S690F2), between steps S690D4 and S690D5 (steps S690F4 and S690F5), and between steps S690D6 and S690D7 (steps S690F6 and S690F7). In this additional step, the fuel state of the fuel cell is restored to its initial value (i.e., the unadjusted value) by a control device. Therefore, in steps S690D and S690F, only one of the temperature state, air supply state, and hydrogen supply state is adjusted each time.

[0070] The fuel cell control system 100, electrochemical detection device 120, and fuel cell control method 600 of this disclosure can adjust the water content state of the fuel cell in real time to improve the power and lifespan of the fuel cell. Furthermore, since the fuel cell control system 100 of this disclosure uses electrochemical analysis to analyze the water content state of the fuel cell, rather than using a voltage detector to detect voltage and then infer the water content state, the accuracy of the analysis of the water content state of the fuel cell can be further improved.

[0071] The above are merely preferred embodiments of this disclosure. Various modifications and equivalent changes can be made to the structure of this disclosure without departing from its scope or concept. In summary, all modifications and equivalent changes made to this disclosure within the scope of the claims are within the scope of this disclosure.

Claims

1. A fuel cell control system for coupling a fuel cell to power a load, comprising: An electrochemical detection device, coupled to the fuel cell, includes: A sensing device for sensing a cell current and a cell voltage of the fuel cell; and A processor, coupled to the sensing device, is used to perform an electrochemical analysis based on the battery voltage and the battery current, and to determine the water content state of the fuel cell based on the electrochemical analysis. A control device, coupled to the fuel cell and the electrochemical detection device, is used to adjust the fuel state of the fuel cell when the water content state of the fuel cell is in a dry membrane state or a flooded state; and A power converter is used to determine a load condition of the fuel cell and generate an output power based on the battery voltage and the battery current when the water content of the fuel cell is in a normal state, wherein the battery voltage and the battery current are related to the load condition.

2. The fuel cell control system of claim 1, wherein the fuel state of the fuel cell includes a hydrogen supply state, an air supply state, and a temperature state. When the water content of the fuel cell is in the dry membrane state, the control device performs at least one of the following operations: Improve the hydrogen supply status; Improve the air supply status; and Lower this temperature state; and When the water content of the fuel cell is in a flooded state, the control device performs at least one of the following operations: Reduce the hydrogen supply status; Reduce the air supply status; and Increase the temperature setting.

3. The fuel cell control system of claim 2, wherein the control device prioritizes operations of increasing the air supply state and decreasing the temperature state over operations of increasing the hydrogen supply state, and The control device prioritizes operations that reduce the air supply and increase the temperature over operations that reduce the hydrogen supply.

4. The fuel cell control system of claim 1, wherein the processor is configured to use the electrochemical analysis to generate a measured electrochemical impedance spectroscopy of the fuel cell and an ideal electrochemical impedance spectroscopy corresponding to the normal state. The water content state is considered to be in the dry film state when at least one of the following conditions is met by the ideal electrochemical impedance spectroscopy and the measured electrochemical impedance spectroscopy: The surface area of ​​the measured electrochemical impedance spectroscopy is larger than the surface area of ​​the ideal electrochemical impedance spectroscopy. The peak value of the measured electrochemical impedance spectroscopy is greater than the peak value of the ideal electrochemical impedance spectroscopy; and The measured electrochemical impedance spectroscopy is a divergent curve; and The water content state is considered to be in a flood state when at least one of the following conditions is met by the ideal electrochemical impedance spectroscopy and the measured electrochemical impedance spectroscopy: The surface area of ​​the measured electrochemical impedance spectroscopy is smaller than the surface area of ​​the ideal electrochemical impedance spectroscopy. The peak value of the measured electrochemical impedance spectroscopy is smaller than the peak value of the ideal electrochemical impedance spectroscopy; and The measured electrochemical impedance spectroscopy is a convergent curve.

5. The fuel cell control system of claim 1, wherein the processor is configured to use the electrochemical analysis to generate a measured high-frequency resistivity spectrum of the fuel cell and an ideal high-frequency resistivity spectrum corresponding to the normal state. Under the same time conditions, when a resistance value in the measured high-frequency resistance spectrum is greater than a resistance value in the ideal high-frequency resistance spectrum, the water content state is in the dry film state; and Under the same time conditions, when the resistance value in the measured high-frequency resistance spectrum is less than the resistance value in the ideal high-frequency resistance spectrum, the water content is in the state of water flooding.

6. The fuel cell control system of claim 1, wherein the processor of the electrochemical detection device is further configured to determine whether a system load of the fuel cell control system is stable, and to perform the electrochemical analysis after the system load is stable.

7. The fuel cell control system of claim 1, wherein the sensing device is used to sense the cell current and the cell voltage of the fuel cell at each inspection cycle; or The sensing device is used to sense the battery current and battery voltage of the fuel cell when an adjustment command is received.

8. A fuel cell control method, applicable to a fuel cell control system, the fuel cell control method comprising the following steps: A load condition for a fuel cell is determined by a power converter; The fuel cell generates a cell voltage and a cell current based on the load conditions and a fuel state of the fuel cell. The battery voltage and battery current are sensed by a sensing device; An electrochemical analysis is performed by a processor based on the battery voltage and the battery current to determine the water content state of the fuel cell. In response to the water content state of the fuel cell being in a dry membrane state or a flooded state, the fuel state of the fuel cell is adjusted by a control device; and In response to the water content of the fuel cell being in a normal state, the power converter generates an output power based on the battery voltage and the battery current.

9. The fuel cell control method of claim 8, wherein the fuel state of the fuel cell includes a hydrogen supply state, an air supply state, and a temperature state. The step of adjusting the fuel state of the fuel cell by the control device in response to the water content state of the fuel cell being in the dry membrane state includes at least one of the following steps: The hydrogen supply status is improved by using this control device; The air supply status is improved through the control device; and The temperature is reduced by the control device; and In response to the water content state of the fuel cell being in a flooded state, the step of adjusting the fuel state of the fuel cell by the control device includes at least one of the following steps: The hydrogen supply is reduced by this control device; The air supply is reduced by the control device; and The temperature is improved by this control device.

10. The fuel cell control method of claim 9, wherein the steps of increasing the air supply state and decreasing the temperature state via the control device have a higher priority than the step of increasing the hydrogen supply state via the control device. The steps of reducing the air supply state and increasing the temperature state by means of the control device have a higher priority than the steps of reducing the hydrogen supply state by means of the control device.

11. The fuel cell control method of claim 8, wherein the step of performing the electrochemical analysis by the processor based on the cell voltage and the cell current to determine the water content state of the fuel cell includes the following steps: The processor generates a measured electrochemical impedance spectroscopy of the fuel cell and an ideal electrochemical impedance spectroscopy corresponding to the normal state based on the battery voltage and the battery current. The processor determines that the water content is in the dry film state when at least one of the following conditions is met by the ideal electrochemical impedance spectroscopy and the measured electrochemical impedance spectroscopy: The surface area of ​​the measured electrochemical impedance spectroscopy is larger than the surface area of ​​the ideal electrochemical impedance spectroscopy. The peak value of the measured electrochemical impedance spectroscopy is greater than the peak value of the ideal electrochemical impedance spectroscopy. as well as The measured electrochemical impedance spectroscopy is a divergent curve; as well as When the ideal electrochemical impedance spectroscopy and the measured electrochemical impedance spectroscopy satisfy at least one of the following conditions, the processor determines that the water content state is in the flood state: The surface area of ​​the measured electrochemical impedance spectroscopy is smaller than the surface area of ​​the ideal electrochemical impedance spectroscopy. The peak value of the measured electrochemical impedance spectroscopy is smaller than the peak value of the ideal electrochemical impedance spectroscopy; and The measured electrochemical impedance spectroscopy is a convergent curve.

12. The fuel cell control method of claim 8, wherein the step of performing the electrochemical analysis by the processor based on the cell voltage and the cell current to determine the water content state of the fuel cell includes the following steps: The processor generates a measured high-frequency resistance spectrum of the fuel cell and an ideal high-frequency resistance spectrum corresponding to the normal state based on the battery voltage and the battery current. In response to a resistance value in the measured high-frequency resistivity spectrum being greater than a resistance value in the ideal high-frequency resistivity spectrum under the same time conditions, the processor determines that the water content state is in the dry film state; and In response to the fact that the resistance value in the measured high-frequency resistance spectrum is less than the resistance value in the ideal high-frequency resistance spectrum under the same time conditions, the processor determines that the water content state is in the state of water flooding.

13. The fuel cell control method of claim 8, wherein the step of performing the electrochemical analysis by the processor based on the cell voltage and the cell current further comprises the following steps: The processor determines whether a system load of the fuel cell control system is stable. In response to the processor determining that the system load is not yet stable, it will remain idle for a specified period of time; and In response to the processor determining that the system load has stabilized, the electrochemical analysis is performed.

14. The fuel cell control method of claim 8, wherein the step of sensing the battery voltage and the battery current by the sensing device is performed in response to each check cycle, or in response to the sensing device receiving an adjustment command.

15. An electrochemical detection device coupled to a fuel cell, the electrochemical detection device comprising: A sensing device for sensing a cell current and a cell voltage generated by the fuel cell according to a fuel state; and A processor, coupled to the sensing device, is used to perform an electrochemical analysis based on the battery voltage and the battery current, and to determine, based on the electrochemical analysis, whether the water content state of the fuel cell is in a normal state, a dry membrane state, or a water flooding state.

16. The electrochemical detection device of claim 15, wherein the fuel state of the fuel cell includes a hydrogen supply state, an air supply state, and a temperature state. When the water content of the fuel cell is in the dry membrane state, the processor performs at least one of the following operations: Instruct a control device to increase the hydrogen supply status; The control device is instructed to increase the air supply status; and The control device is instructed to lower the temperature; and When the water content of the fuel cell is in a flooded state, the processor performs at least one of the following operations: The control device is instructed to reduce the hydrogen supply. The control device is instructed to reduce the air supply status; and The control device is instructed to increase the temperature.

17. The electrochemical detection device of claim 16, wherein the processor instructs the control device to increase the air supply state and decrease the temperature state with a higher priority than instructing the control device to increase the hydrogen supply state, and The processor prioritizes instructing the control device to reduce the air supply and increase the temperature over instructing it to reduce the hydrogen supply.

18. The electrochemical detection apparatus of claim 15, wherein the processor is configured to use the electrochemical analysis to generate a measured electrochemical impedance spectroscopy of the fuel cell and an ideal electrochemical impedance spectroscopy corresponding to the normal state. The processor determines that the water content state is in the dry film state when at least one of the following conditions is met by the ideal electrochemical impedance spectroscopy and the measured electrochemical impedance spectroscopy: The surface area of ​​the measured electrochemical impedance spectroscopy is larger than the surface area of ​​the ideal electrochemical impedance spectroscopy. The peak value of the measured electrochemical impedance spectroscopy is greater than the peak value of the ideal electrochemical impedance spectroscopy; and The measured electrochemical impedance spectroscopy is a divergent curve; and The water content state is considered to be in a flood state when at least one of the following conditions is met by the ideal electrochemical impedance spectroscopy and the measured electrochemical impedance spectroscopy: The surface area of ​​the measured electrochemical impedance spectroscopy is smaller than the surface area of ​​the ideal electrochemical impedance spectroscopy. The peak value of the measured electrochemical impedance spectroscopy is smaller than the peak value of the ideal electrochemical impedance spectroscopy; and The measured electrochemical impedance spectroscopy is a convergent curve.

19. The electrochemical detection apparatus of claim 15, wherein the processor is configured to use the electrochemical analysis to generate a measured high-frequency resistivity spectrum of the fuel cell and an ideal high-frequency resistivity spectrum corresponding to the normal state. Under the same time conditions, when a resistance value in the measured high-frequency resistance spectrum is greater than a resistance value in the ideal high-frequency resistance spectrum, the processor determines that the water content state is in the dry film state; and Under the same time conditions, when the resistance value in the measured high-frequency resistance spectrum is less than the resistance value in the ideal high-frequency resistance spectrum, the processor determines that the water content is in the state of water flooding.

20. The electrochemical detection device of claim 15, wherein the processor is further configured to determine whether a system load of a fuel cell control system in which the fuel cell is located is stable, and to perform the electrochemical analysis after the system load is stable.

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