An apparatus and method for acquiring zoned electrochemical impedance spectroscopy for a fuel cell
By applying overall excitation to the fuel cell and simultaneously measuring current and voltage, the process of obtaining the regional electrochemical impedance spectrum is simplified, solving the problems of complex steps and expensive equipment in the existing technology, and realizing efficient and convenient multi-region monitoring.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2023-09-25
- Publication Date
- 2026-05-29
AI Technical Summary
Existing techniques for obtaining regional electrochemical impedance spectroscopy involve complex steps, sophisticated equipment, and high costs, making it difficult to achieve efficient and convenient monitoring of various regions of a fuel cell.
By applying overall excitation to the fuel cell and simultaneously measuring the current and voltage of each zone, the electrochemical impedance spectroscopy is obtained using the PCB signal acquisition unit and data acquisition unit, simplifying the testing steps and reducing equipment complexity.
It enables efficient and convenient acquisition of electrochemical impedance spectra of various zones of fuel cells. The equipment is easy to manufacture, the testing process is simple, it supports simultaneous measurement of multiple zones, closely approximates the native operating environment, and provides a basis for control.
Smart Images
Figure CN117289160B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of measurement technology for proton exchange membrane fuel cells, and more particularly to a device and method for obtaining partitioned electrochemical impedance spectroscopy for fuel cells. Background Technology
[0002] Proton exchange membrane fuel cells (PEMFCs) have attracted widespread attention in recent years as an environmentally friendly, efficient, and low-noise energy conversion device. With the advancement of their commercialization, increasing the size of the membrane electrode assembly (MEA) has become a simple and effective way to reduce costs and improve power density. However, with the increase in size, the inconsistency of operating conditions in different parts of the MEA results in uneven performance output across different regions. This unevenness will have an adverse effect on the fuel cell, reducing its power density and shortening its lifespan. Therefore, effective monitoring of the operating status of different regions of the fuel cell has become crucial for ensuring power density and extending its lifespan.
[0003] Current zonal testing technologies are mainly divided into two categories. The first is physical characterization, such as X-ray imaging and neutron imaging. The advantage of this imaging method is that it can acquire the water distribution inside the fuel cell in real time, thereby inferring the current operating status of each region inside the fuel cell. However, this method also has significant drawbacks: it can generally only infer the state of each region through the distribution of water, and the equipment is large and expensive. The other category is electrochemical characterization, which includes short-circuit current distribution testing, hydrogen permeation distribution testing, and local electrochemical impedance spectroscopy testing. The first two require changing the working gas of the fuel cell and can only be used when the fuel cell is shut down. Zonal electrochemical impedance spectroscopy technology has the advantages of electrochemical impedance spectroscopy technology, while also allowing for online monitoring of the operating status of each zone of the fuel cell.
[0004] Existing patents for obtaining sectional electrochemical impedance spectroscopy (TIS) are few. CN109828216B employs a method of isolating the area to be measured and applying a perturbation independently to obtain the sectional TES. This method requires removing the test area from its original load while simultaneously applying an independent load with the same current as before removal. Then, a perturbation is applied to the area individually, and the response is obtained. Finally, the TES is obtained by analyzing the relationship between the perturbation and the response. This approach requires complex equipment, especially the structure required for the removal step, which significantly increases the number of components on the PCB. Furthermore, the measurement results after removing the original load differ somewhat from those obtained through in-situ testing. Summary of the Invention
[0005] To address the aforementioned technical problems with the complex and cumbersome implementation of existing techniques for obtaining partitioned electrochemical impedance spectroscopy (EIS), this invention provides a device and method for obtaining partitioned EIS spectra for fuel cells. This invention provides overall excitation to the fuel cell, followed by simultaneous measurement of the current and voltage in each partition, thereby obtaining the EIS spectrum of each partition. This reduces the difficulty of obtaining EIS spectra and makes the testing simpler and more efficient.
[0006] The technical means employed in this invention are as follows:
[0007] An apparatus for obtaining partitioned electrochemical impedance spectroscopy for fuel cells, comprising:
[0008] The fuel cell is provided with two end plates, two current collectors, a PCB signal acquisition unit, two gas distribution plates, and a fuel cell membrane electrode assembly arranged sequentially from the outside to the inside.
[0009] The PCB signal acquisition unit includes a first partition electrode plate and a current and voltage acquisition unit. The current and voltage acquisition unit includes a concentrated current plate, a current acquisition device, and a second partition electrode plate arranged sequentially from the outside to the inside and connected to each other. The first partition electrode plate is disposed inside one current collector plate, the concentrated current plate is disposed inside another current collector plate, and the second partition electrode plate is disposed outside the gas distribution plate. The current and voltage acquisition unit is used to measure current information, and the current and voltage acquisition unit and the first partition electrode plate are used to jointly acquire voltage information.
[0010] An excitation source is connected in parallel with the current collector of the fuel cell, and the excitation source is used to apply an excitation signal to the fuel cell;
[0011] The data acquisition unit is connected to the first partition electrode plate, the second partition electrode plate, and the two ends of the current acquisition device of the fuel cell, respectively. The data acquisition unit is used to acquire the current and voltage signals generated by the fuel cell after receiving excitation, and send the acquired current and voltage signals to the signal processing unit.
[0012] The signal processing unit is connected to the data acquisition unit and is used to calculate and obtain the electrochemical impedance spectrum of each section of the fuel cell based on the voltage and current signals of each section.
[0013] Furthermore, the fuel cell is a stack fuel cell or a single-cell fuel cell.
[0014] Furthermore, when the fuel cell is a stack fuel cell, the gas distribution plate is a bipolar plate; when the fuel cell is a single-cell fuel cell, the gas distribution plate is a flow field plate.
[0015] Furthermore, the current acquisition device is a current sampling resistor or a chip that uses the Hall effect to calculate the current. The current sampling resistor obtains the current magnitude of each zone by measuring the voltage drop across the current.
[0016] The present invention also provides a method for obtaining partitioned electrochemical impedance spectroscopy for fuel cells, implemented based on any of the above-mentioned devices for obtaining partitioned electrochemical impedance spectroscopy for fuel cells, comprising the following steps:
[0017] S1. The excitation source determines the excitation amount for the fuel cell according to the current operating conditions and applies an excitation signal to the fuel cell.
[0018] S2. The PCB signal acquisition units on both sides of the fuel cell under test measure the current and voltage signals of each zone of the fuel cell and send them to the data acquisition unit.
[0019] S3. The data acquisition unit converts the current and voltage signals into digital signals and sends them to the data processing unit. The data processing unit calculates and obtains the electrochemical impedance spectrum of each partition of the fuel cell based on the voltage and current signals of each partition.
[0020] Furthermore, in the fuel cell, the current signal acquisition path and voltage acquisition path in each zone are acquired synchronously, and the sampling rate is determined according to the highest frequency of the required electrochemical impedance spectroscopy. If the highest frequency to be measured is a Hz, then the sampling rate is greater than 2a Hz.
[0021] Furthermore, the excitation signal is a current signal or a voltage signal, the excitation amplitude of the current signal is in the range of 3%-12% of the current load current of the fuel cell; the excitation amplitude of the voltage signal is in the range of 3mV-10mV, and the type of the excitation signal is one of a single sine wave signal, a superimposed multiple sine wave signal, a pseudo-random binary signal, and a chirped signal.
[0022] Furthermore, in S3, the data processing unit obtains the impedance value of each partition by performing Fourier transform on the time-domain data of the current and voltage signals of each partition, thereby obtaining the impedance value of each frequency, and then obtaining the electrochemical impedance spectrum of each partition.
[0023] Furthermore, the range of the highest frequency is 0.1 Hz to 50 kHz.
[0024] Compared with the prior art, the present invention has the following advantages:
[0025] (1) This invention effectively solves the existing problems of high difficulty and complex acquisition steps in efficiently and conveniently acquiring the electrochemical impedance of fuel cells by designing a PCB acquisition device for acquiring the current and voltage distribution of fuel cells and combining it with a method of uniformly applying a disturbance and measuring the actual disturbance and response of each zone. Compared with the existing technology, the PCB equipment required by this solution is easy to process, the test process is easy to execute, the test equipment is easy to acquire, and it can realize the simultaneous measurement of impedance spectra of multiple zones, which has strong advantages over the existing technology.
[0026] (2) This invention achieves simultaneous measurement of electrochemical impedance of multiple zones in a proton exchange membrane fuel cell by adding a set of current and voltage measurement PCBs and applying a disturbance to the whole and measuring the actual disturbance in zones. Compared with the method of measuring the zones separately, this method has a simpler structure, is closer to the original operating environment of the fuel cell, and can realize simultaneous testing of multiple zones. It provides a probe for monitoring the operation process of the proton exchange membrane fuel cell and provides a basis for designing and adjusting its control system and control strategy. Attached Figure Description
[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention.
[0029] Figure 2 This is a schematic diagram of the fuel cell of the present invention.
[0030] Figure 3 for Figure 2 Enlarged view of point A.
[0031] Figure 4 This is a diagram showing the partitioning of the fuel cell in this invention.
[0032] Figure 5 The graph shows the results of the electrochemical impedance spectroscopy test in zonal regions of Examples 1-16 of the present invention.
[0033] Figure 6 The graph shows the results of the electrochemical impedance spectroscopy test in sections 17-32 of this invention.
[0034] In the diagram: 1. Fuel cell; 2. End plate; 3. Current collector; 4. PCB signal acquisition unit; 5. Gas distribution plate; 6. Fuel cell membrane electrode; 7. First partition electrode plate; 8. Concentrated current plate; 9. Current acquisition device; 10. Second partition electrode plate; 11. Excitation source; 12. Data acquisition unit; 13. Signal processing unit. Detailed Implementation
[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.
[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0038] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.
[0039] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.
[0040] like Figure 1-3 As shown, the present invention provides a device for obtaining partitioned electrochemical impedance spectroscopy for fuel cells, comprising:
[0041] Fuel cell 1, wherein the fuel cell 1 is provided with two end plates 2, two current collectors 3, a PCB signal acquisition unit 4, two gas distribution plates 5 and a fuel cell membrane electrode 6 arranged sequentially from the outside to the inside, and the end plates 2, current collectors 3, PCB signal acquisition units 4, gas distribution plates 5 and fuel cell membrane electrode 6 are connected in sequence.
[0042] The fuel cell 1 is either a stack fuel cell 1 or a single-cell fuel cell 1. When the fuel cell 1 is a stack fuel cell, the gas distribution plate 5 is a bipolar plate; when the fuel cell 1 is a single-cell fuel cell, the gas distribution plate 5 is a flow field plate.
[0043] The PCB signal acquisition unit 4 includes a first partition electrode plate 7 and a current and voltage acquisition unit. The current and voltage acquisition unit includes a concentrated current plate 8, a current acquisition device 9, and a second partition electrode plate 10 arranged and connected sequentially from the outside to the inside. The first partition electrode plate 7 is disposed inside one current collector 3, the concentrated current plate 8 is disposed inside another current collector 3, and the second partition electrode plate 10 is disposed outside the gas distribution plate 5. The current and voltage acquisition unit is used to measure current information, and the current and voltage acquisition unit and the first partition electrode plate 7 are used to jointly acquire voltage information. The first partition electrode plate 7, the second partition electrode plate 10, and the concentrated current plate 8 are all manufactured using printed circuit board technology.
[0044] The current acquisition device 9 is a current sampling resistor or a chip that uses the Hall effect to calculate the current. The current sampling resistor obtains the current magnitude of each zone by measuring the voltage drop across the current.
[0045] Excitation source 11 is connected in parallel with current collector 3 of fuel cell 1, and excitation source 11 is used to apply excitation signal to fuel cell 1;
[0046] The data acquisition unit 12 is connected to the two ends of the first partition electrode plate 7, the second partition electrode plate 10, and the current acquisition device 9 of the fuel cell 1, respectively. The data acquisition unit 12 is used to acquire the current and voltage signals generated by the fuel cell 1 after receiving excitation, and send the acquired current and voltage signals to the signal processing unit 13.
[0047] The signal processing unit 13 is connected to the data acquisition unit 12. The signal processing unit 13 is used to calculate and obtain the electrochemical impedance spectrum of each partition of the fuel cell 1 based on the voltage and current signals of each partition.
[0048] This invention also provides a method for obtaining partitioned electrochemical impedance spectroscopy for fuel cells, implemented using a device for obtaining partitioned electrochemical impedance spectroscopy for fuel cells, comprising the following steps:
[0049] S1. Excitation source 11 determines the excitation amount to fuel cell 1 according to the current operating conditions and applies an excitation signal to fuel cell 1.
[0050] S2. The PCB signal acquisition unit 4 on both sides of the single cell of the fuel cell 1 under test measures the current and voltage signals of each zone of the fuel cell 1 and sends them to the data acquisition unit 12.
[0051] S3. The data acquisition unit 12 converts the current and voltage signals into digital signals, records them, and sends them to the data processing unit. The data processing unit calculates and obtains the electrochemical impedance spectrum of each partition of the fuel cell 1 based on the voltage and current signals of each partition.
[0052] In S3, the data processing unit converts the time domain of the current and voltage signals of each partition into the frequency domain and then obtains the impedance value of each partition through Fourier transform, thereby obtaining the impedance value of each frequency and then obtaining the electrochemical impedance spectrum of each partition.
[0053] In the fuel cell 1, the current signal acquisition path and voltage acquisition path in each section are synchronously acquired. The sampling rate is determined according to the highest frequency of the required electrochemical impedance spectroscopy. The frequency information included in the excitation signal is a series of frequencies from 0.1 to 20 kHz, or a certain frequency within that range. The sampling rate of the data acquisition unit is determined according to the highest frequency to be measured. When the highest frequency to be measured is a Hz, the sampling rate of the data acquisition unit cannot be lower than 2a Hz.
[0054] The excitation signal is a current signal or a voltage signal. The excitation amplitude of the current signal is in the range of 3%-12% of the current load current of fuel cell 1. The excitation amplitude of the voltage signal is in the range of 3mV-10mV. The excitation signal is one of a single sine wave signal, a superimposed multiple sine wave signal, a pseudo-random binary signal, and a chirped signal.
[0055] Example
[0056] This example is for 50cm. 2 The invention is implemented in a single cell of a fuel cell to obtain the electrochemical impedance spectroscopy of each zone of the fuel cell during operation.
[0057] The specific equipment includes a fuel cell stack, an excitation source 11, a PCB signal acquisition unit 4, a data acquisition unit 12, and a data processing unit 13. The PCB signal acquisition unit 4 will test the electrochemical impedance spectroscopy of 32 zones of the fuel cell, and their distribution is as follows: Figure 4 As shown, there are 8 sections horizontally and 4 sections vertically.
[0058] The operating current of fuel cell 1 during measurement was 1200 mA cm. -2 The excitation source 11 uses current excitation. In this embodiment, the excitation is a superimposed excitation of multiple sine waves with an amplitude of 3A and a frequency range of 1-3kHz.
[0059] After the excitation source 11 applies excitation to the system under test, the data acquisition unit 12 will acquire the actual excitation current and response voltage of each partition at a sampling rate of 128kHz. In this embodiment, the actual excitation current of each partition will be acquired using a sampling resistor with a value of 20mΩ.
[0060] After collecting excitation and response signals for multiple full cycles, the data acquisition unit 12 uploads the data to the data processing unit 13. The data processing unit 13 performs Fourier transforms on the current and voltage signals respectively, converting the time-domain signals into frequency-domain signals. Then, by dividing the voltage and current in the frequency domain, the electrochemical impedance spectroscopy of each region can be obtained. The experimental results are as follows: Figure 5 and 6 As shown.
[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A device for acquiring partitioned electrochemical impedance spectroscopy for fuel cells, characterized in that, include: A fuel cell (1) is provided with two end plates (2), two current collectors (3), a PCB signal acquisition unit (4), two gas distribution plates (5), and a fuel cell membrane electrode (6) in sequence from the outside to the inside. The end plates (2), current collectors (3), PCB signal acquisition unit (4), gas distribution plates (5) and fuel cell membrane electrode (6) are connected in sequence. The PCB signal acquisition unit (4) includes a first partition electrode plate (7) and a current and voltage acquisition unit. The current and voltage acquisition unit includes a concentrated current plate (8), a current acquisition device (9), and a second partition electrode plate (10) arranged and connected sequentially from the outside to the inside. The first partition electrode plate (7) is disposed inside a current collector (3), the concentrated current plate (8) is disposed inside another current collector (3), and the second partition electrode plate (10) is disposed outside the gas distribution plate (5). The current and voltage acquisition unit is used to measure current information, and the current and voltage acquisition unit and the first partition electrode plate (7) are used to jointly acquire voltage information. An excitation source (11) is connected in parallel with the current collector (3) of the fuel cell (1), and the excitation source (11) is used to apply an excitation signal to the fuel cell (1). The data acquisition unit (12) is connected to the first partition electrode plate (7), the second partition electrode plate (10), and the current acquisition device (9) of the fuel cell (1) respectively. The data acquisition unit (12) is used to acquire the current and voltage signals generated by the fuel cell (1) after receiving excitation, and send the acquired current and voltage signals to the signal processing unit (13). The signal processing unit (13) is connected to the data acquisition unit (12). The signal processing unit (13) is used to calculate and obtain the electrochemical impedance spectrum of each partition of the fuel cell (1) based on the voltage and current signals of each partition.
2. The device for obtaining partitioned electrochemical impedance spectroscopy for fuel cells according to claim 1, characterized in that, The fuel cell (1) is either a stack fuel cell (1) or a single-cell fuel cell (1).
3. The device for obtaining partitioned electrochemical impedance spectroscopy for fuel cells according to claim 2, characterized in that, When the fuel cell (1) is a stack fuel cell, the gas distribution plate (5) is a bipolar plate; when the fuel cell (1) is a single cell fuel cell, the gas distribution plate (5) is a flow field plate.
4. The device for obtaining partitioned electrochemical impedance spectroscopy for fuel cells according to claim 1, characterized in that, The current acquisition device (9) is a current sampling resistor or a chip that uses the Hall effect to calculate the current. The current sampling resistor obtains the current magnitude of each zone by the voltage drop across the current.
5. A method for obtaining partitioned electrochemical impedance spectroscopy for fuel cells, implemented based on the partitioned electrochemical impedance spectroscopy acquisition device for fuel cells according to any one of claims 1-4, characterized in that, Includes the following steps: S1. The excitation source (11) determines the excitation amount to the fuel cell (1) according to the current operating conditions and applies an excitation signal to the fuel cell (1); S2. The PCB signal acquisition unit (4) on both sides of the single cell of the fuel cell (1) under test measures the current and voltage signals of each section of the fuel cell (1) and sends them to the data acquisition unit (12). S3, the data acquisition unit (12) converts the current and voltage signals into digital signals and sends them to the data processing unit. The data processing unit calculates and obtains the electrochemical impedance spectrum of each partition of the fuel cell (1) based on the voltage and current signals of each partition.
6. The method for obtaining partitioned electrochemical impedance spectroscopy for fuel cells according to claim 5, characterized in that, In the fuel cell (1), the current signal acquisition path and voltage acquisition path in each partition are synchronously acquired. The sampling rate is determined according to the highest frequency of the required electrochemical impedance spectrum. If the highest frequency to be measured is a Hz, the sampling rate is greater than 2a Hz.
7. The method for obtaining partitioned electrochemical impedance spectroscopy for fuel cells according to claim 5, characterized in that, The excitation signal is a current signal or a voltage signal. The excitation amplitude of the current signal is in the range of 3%-12% of the current load current of the fuel cell (1). The excitation amplitude of the voltage signal is in the range of 3mV-10mV. The type of the excitation signal is one of a single sine wave signal, a superimposed multiple sine wave signal, a pseudo-random binary signal, and a chirped signal.
8. The method for obtaining partitioned electrochemical impedance spectroscopy for fuel cells according to claim 5, characterized in that, In S3, the data processing unit obtains the impedance value of each partition by performing Fourier transform on the time-domain data of the current and voltage signals of each partition, thereby obtaining the impedance value of each frequency, and then obtaining the electrochemical impedance spectrum of each partition.
9. The method for obtaining partitioned electrochemical impedance spectroscopy for fuel cells according to claim 6, characterized in that, The highest frequency range is 0.1 Hz to 50 kHz.