A method and device for synchronously detecting parameters of a fuel cell multi-partition membrane electrode

Abstract

The present application relates to fuel cell parameter detection technical field, disclose a kind of fuel cell multi-partition membrane electrode parameter synchronous detection method and device, comprising: constructing double working condition test procedure, set membrane electrode parameter and alternating current impedance detection working condition sequentially or independently executed and share same partition acquisition device and spatial coordinate mapping;Fuel cell embedded in partition acquisition device is connected to test system;Under different gas input conditions, respectively apply ac and dc excitation signal, synchronously obtain partition excitation and its response signal and extract each partition membrane electrode parameter and alternating current impedance spectrum data;Fusion each partition data generates electrochemical parameter spatial distribution result.The present application realizes the decoupling extraction of multidimensional electrochemical parameters in time domain by double working condition test and spatial array operation, can determine fuel cell membrane electrode parameter distribution difference, performance distribution difference, aging degree distribution difference and damage location, provide method for distribution difference analysis and performance optimization.

Description

Technical Field

[0001] This invention relates to the field of fuel cell parameter detection technology, specifically to a method and apparatus for synchronous detection of multi-zone membrane electrode parameters in fuel cells. Background Technology

[0002] The internal reaction of a fuel cell involves electrochemical and gas-liquid mass transfer processes. Affected by the flow field structure and gas concentration gradient, the operating state of different regions of the membrane electrode varies significantly. The spatial distribution characteristics of the acquired parameters play an important role in the diagnosis of the battery's health status. Conventional tests are mostly based on external endplates to obtain overall voltage and current. This lumped parameter measurement method masks the internal local performance differences and cannot characterize the true degradation of local materials. Therefore, it is necessary to introduce a zoned detection technology.

[0003] Existing multi-zone detection technology requires changing the acquisition equipment according to different operating conditions when acquiring electrochemical parameters in different dimensions. This not only increases the test time, but also introduces environmental interference variables due to frequent switching of hardware and gas path states, making it difficult to achieve consistent coordinate mapping of data acquired under different test conditions on physical space nodes.

[0004] Furthermore, when extracting fundamental parameters such as double-layer capacitance and hydrogen desorption charge, existing methods often involve electrochemical testing of the entire system, which makes it difficult to reflect the characteristics of local electrochemical parameters and to achieve accurate decoupling and extraction of multi-dimensional parameters in the time domain. The cumbersome testing process and the limitations of parameter calculation methods make it difficult for existing technologies to establish accurate spatial distribution mapping models and accurately locate differences in the distribution of membrane electrode parameters, performance, aging degree, and damage location in fuel cells. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and apparatus for synchronous detection of multi-zone membrane electrode parameters in fuel cells. This solves the problem that existing testing technologies are unable to synchronously acquire and establish spatial distribution mapping relationships of multiple physical fields and electrochemical parameters under fuel cell operating conditions, leading to inaccurate local fault location due to differences in membrane electrode parameter distribution, performance distribution, aging degree distribution, and damage location.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of this invention provides a method for synchronous detection of multi-zone membrane electrode parameters in a fuel cell, comprising: A dual-condition test process was constructed, and the membrane electrode parameter detection condition and the AC impedance detection condition were set to be executed sequentially and share the same partition acquisition device and the same spatial coordinate mapping relationship. Establish system hardware connections and connect the fuel cell with its internally embedded partition acquisition device to the test system; The membrane electrode parameter detection operation is performed by introducing pure nitrogen gas into the test electrode side of the fuel cell and pure hydrogen gas into the reference electrode side, applying a DC excitation signal, and simultaneously acquiring the DC excitation and response signals of each zone in the zone acquisition device and calculating the membrane electrode parameters of each zone. The AC impedance detection condition is executed by switching the fuel cell test electrode side to air and keeping pure hydrogen flowing through the reference electrode side, applying a perturbation AC excitation signal, and simultaneously acquiring the AC excitation and response signals of each zone and extracting local AC impedance spectrum data. The system generates spatial distribution detection results, integrates membrane electrode parameters and local AC impedance spectroscopy data from each region, and outputs electrochemical parameter distribution data covering all spatial regions.

[0007] Furthermore, the steps for performing membrane electrode parameter detection include: At least four constant DC current excitation signals of different amplitudes are continuously applied to the fuel cell, and the electrochemical response curves of each partition corresponding to the spatial coordinates are acquired simultaneously. Extract the excitation current and response voltage data and the corresponding response time data within the preset feature range to form a feature data subset; Based on the physical mechanism that the excitation charge is equal to the sum of the electric double layer capacitance charging charge, hydrogen permeation charge, short-circuit charge, and hydrogen desorption charge, a multivariable charge conservation equation is established. The feature data subset is processed, and the response time corresponding to each response is used as the integration interval. Time integration is performed on the local excitation current data and the local response voltage data respectively, and the obtained integral values ​​are divided by the corresponding response time to obtain the local excitation current time average and the local response voltage time average. Perform the reciprocal operation on each response time to obtain the reciprocal data of the response time; extract the response voltage jump value at the initial stage of each excitation, and perform ohmic voltage drop correction on the local response voltage based on the response voltage jump value to obtain the potential difference at the test electrode interface and its initial value. The average rate of change of the test electrode interface potential difference is obtained by dividing the difference between the test electrode interface potential difference and its initial value by the corresponding response time. The average local excitation current over time, the average local response voltage over time, the reciprocal of the response time, and the average rate of change of the potential difference at the test electrode interface are used to construct an input excitation column vector and a characteristic coefficient matrix in a preset order. These are then substituted into a set of matrix equations, and least squares operations are performed to obtain the characteristic values ​​of basic electrochemical parameters covering double-layer capacitance, short-circuit resistance, hydrogen permeation current density, and hydrogen desorption charge.

[0008] By establishing a multivariate algebraic model based on the charge conservation mechanism, the nonlinear electrochemical process is transformed into a system of linear matrix equations, thereby achieving the decoupled extraction of multidimensional electrochemical parameters in the time domain.

[0009] Furthermore, the steps for calculating the membrane electrode parameters for each partition include: The local hydrogen desorption charge was extracted and the electrochemical active area of ​​the corresponding partition was calculated by combining it with the platinum loading of the target partition. The basic electrochemical eigenvalues ​​of all partitions are arranged into a spatial arrangement matrix based on physical topological coordinates; An array operation based on element-wise division is performed on the hydrogen desorption charge matrix covering the global spatial dimension and the platinum loading matrix in the corresponding coordinates, outputting an electrochemical active area matrix covering all spatial dimensions and completing the synchronous calculation process of parameters for each partition.

[0010] Furthermore, the steps for performing AC impedance detection include: controlling the electronic load to maintain the steady-state DC discharge operating point of the fuel cell, and superimposing a micro-perturbation AC excitation signal within a set frequency band range onto the main circuit of the fuel cell; Synchronously acquire the time-domain voltage timing signal and time-domain current timing signal collected from each partition; The frequency domain transformation operation is performed on the time domain signal array of each partition using fast Fourier transform, sine fitting or phase-locked demodulation to generate frequency domain voltage data and frequency domain current data in the complex domain; Perform frequency node-based sequence integration operations to extract local AC impedance spectrum data covering the entire measurement frequency band from high frequency to low frequency.

[0011] Furthermore, the steps for generating spatial distribution detection results include: calling the corresponding physical topological coordinate information based on the preset matrix row and column numbers, and performing array alignment operation based on spatial coordinate nodes for the extracted membrane electrode parameters and local AC impedance spectrum data; A multidimensional spatial fusion dataset covering internal reaction characteristics, hardware insulation characteristics, and AC frequency domain impedance characteristics is constructed, and the numerical values ​​of each dimension matrix are mapped to a spatial distribution state topology that matches the actual flow field geometry of the fuel cell. Extract the electrochemical characteristic parameters corresponding to each physical coordinate node, calculate the deviation difference between the data and the benchmark characteristic data, and perform a comparison operation based on a preset deviation threshold. The preset deviation threshold is determined by the benchmark characteristic data measured under the same operating conditions under the calibrated healthy state, combined with the set fault tolerance floating ratio. Output an engineering diagnostic coordinate report indicating the local catalyst performance degradation area, abnormal hydrothermal distribution area, and proton exchange membrane mechanical damage risk location inside the fuel cell.

[0012] Furthermore, the steps for constructing the dual-condition test process include: mapping the physical installation area corresponding to each hardware acquisition channel in the partition acquisition device to the corresponding spatial coordinate identifier, and pre-establishing a one-to-one correspondence between the acquisition channel number and the spatial coordinate identifier; Sending control command frames containing timing tags to external devices schedules the action of gas circuit valves and the switching of circuit relays, and controls the sequential or individual operation of membrane electrode parameter detection and AC impedance detection.

[0013] A second aspect of the present invention provides a device for synchronously detecting the parameters of a multi-zone membrane electrode assembly (MEA) in a fuel cell, for implementing the aforementioned method for synchronously detecting the parameters of a multi-zone MEA in a fuel cell. The device includes: The gas supply system is located at the gas input end of the fuel cell and switches between supplying different types of test gases to the test electrode side and the reference electrode side of the fuel cell according to the test command. The excitation signal source is electrically connected to the fuel cell and is used to output DC excitation signals and AC perturbation excitation signals; An electronic load, connected to the fuel cell main circuit, is used to maintain the steady-state discharge boundary of the fuel cell. The partitioned acquisition device is installed inside the fuel cell at a projection position corresponding to the flow field reaction region. It has multiple partitioned structures that are insulated from each other, and is used to synchronously acquire the excitation and response signals of different spatial regions. The data acquisition unit is connected to the signal output terminal of the partition acquisition device for synchronously receiving voltage and current change signals. The data processing unit is connected to the data acquisition unit and is used to parse the synchronization signal and perform matrix equation calculations and array operations through the underlying algebra operation library, outputting the global distribution characteristic state values ​​of multidimensional parameters.

[0014] Furthermore, the partitioned acquisition device includes a test electrode sampling plate and a reference electrode sampling plate. The conductive surface of the test electrode sampling plate is attached to the non-fluid surface of the bipolar plate on the test electrode side, and the conductive surface of the reference electrode sampling plate is attached to the non-fluid surface of the bipolar plate on the reference electrode side. The sampling areas of the test electrode sampling board and the reference electrode sampling board are divided into matrix-style insulating partitions with m rows and n columns. Each insulating partition is electrically isolated from the others by an insulating dielectric layer, where m and n are both positive integers greater than or equal to 2.

[0015] Furthermore, each insulating partition of the test electrode sampling plate serves as a local excitation current acquisition partition, and is connected to the current acquisition channel of the data acquisition device through a corresponding independent signal terminal, for acquiring the local excitation current signal within the corresponding spatial partition of the fuel cell. Each insulation zone of the reference electrode sampling board and each insulation zone corresponding to the spatial coordinates in the test electrode sampling board form a local differential voltage sampling pair. Each local differential voltage sampling pair is connected to the differential voltage acquisition channel of the data acquisition device to obtain the local response voltage signal between the reference electrode sampling board and the test electrode sampling board in the corresponding spatial zone. The data acquisition unit is used to synchronously acquire the local excitation current signal and local response voltage signal of each spatial partition, and transmit the local excitation current signal and local response voltage signal to the data processing unit according to the corresponding matrix row and column coordinates.

[0016] Furthermore, the data processing unit has a built-in algebraic operation library at the bottom layer. This library is used to perform element-wise division of spatially arranged matrices and least squares operations on system of equations matrices through concurrent processing of matrix arrays.

[0017] This invention provides a method and apparatus for synchronous detection of multi-zone membrane electrode parameters in fuel cells. It has the following advantages: 1. This invention constructs a dual-condition test process, which allows membrane electrode parameter detection and AC impedance detection to be performed sequentially and share the same partition acquisition device and spatial coordinate mapping relationship. This avoids the differences in environmental variables introduced by frequent hardware disassembly and assembly in multiple tests, and ensures the consistency of DC response data and AC impedance data at physical spatial nodes.

[0018] 2. This invention establishes relational equations based on the charge conservation mechanism and processes feature data using the least squares operation of the matrix equation system. This enables the decoupling and extraction of multi-dimensional electrochemical parameters such as double-layer capacitance, short-circuit resistance, and hydrogen desorption charge in the time domain, thereby reducing calculation bias caused by the coupling of multiple parameters.

[0019] 3. This invention constructs a multi-dimensional spatial fusion dataset by integrating membrane electrode parameters from each region with local AC impedance spectral data, and directly maps the values ​​to the spatial state topology that matches the actual flow field of the fuel cell. Combined with the comparison calculation of benchmark feature data, it can directly output the physical coordinates of abnormal distribution of fuel cell membrane electrode parameters, abnormal distribution of performance, abnormal distribution of aging degree, and damage location. This solves the technical problem of difficult accurate location of local faults inside the fuel cell and provides a method for distribution difference analysis and performance optimization. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the synchronous detection device for multi-zone membrane electrode parameters of fuel cells according to the present invention; Figure 2 This is a flowchart illustrating the synchronous detection method for multi-zone membrane electrode parameters in fuel cells according to the present invention. Figure 3This is a schematic diagram of the test control process and hardware partitioning assembly of the present invention; Figure 4 This is a schematic diagram of the process for executing membrane electrode parameter detection and synchronous parameter calculation according to the present invention. Figure 5 This is a schematic diagram of the process for executing AC impedance detection under operating conditions and generating spatial distribution diagnostic results according to the present invention. Figure 6 This is a three-dimensional bar chart showing the spatial distribution of hydrogen permeation current density in 16 zones according to the present invention. Figure 7 This is a three-dimensional bar chart showing the spatial distribution of the 16-zone electrochemical active area of ​​the present invention.

[0021] Among them, 10 is the gas supply system; 20 is the excitation signal source; 30 is the electronic load; 40 is the fuel cell test bench; 50 is the zone acquisition device; 51 is the test electrode sampling plate; 52 is the reference electrode sampling plate; 60 is the data acquisition unit; and 70 is the data processing unit. Detailed Implementation

[0022] The technical solutions in 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. 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.

[0023] For ease of description, in this embodiment, the test electrode side refers to the side in which nitrogen is introduced under the membrane electrode parameter detection condition and air is introduced under the AC impedance detection condition; the reference electrode side or reference electrode side refers to the side in which hydrogen is introduced under both conditions; synchronous detection in this article refers to the synchronous acquisition and calculation of the excitation and response signals of multiple spatial partitions within the same detection condition, and does not mean that the membrane electrode parameter detection condition and the AC impedance detection condition are performed simultaneously; the two conditions are executed independently, and parameter correlation is achieved through a shared partition acquisition device and a unified spatial coordinate mapping.

[0024] See attached document Figure 1 This invention provides a device for synchronously detecting the parameters of multi-zone membrane electrode assemblies in fuel cells, comprising: The gas supply system 10 is configured at the gas input end of the fuel cell. It switches the gas type according to different operating conditions set by the detection method. The gas supply system 10 supplies nitrogen or air to the test electrode side of the fuel cell and hydrogen to the reference electrode side of the fuel cell. Excitation signal source 20 is electrically connected to the fuel cell and provides the excitation signal required for testing. Under the condition of membrane electrode parameter detection, excitation signal source 20 outputs DC current excitation or DC voltage excitation to the fuel cell. Under the condition of AC impedance detection, excitation signal source 20 outputs AC voltage excitation or AC current excitation to the fuel cell. The electronic load 30 is connected to the fuel cell via a cable. Under AC impedance detection conditions, it consumes the electrical energy generated by the fuel cell and helps to adjust the working state of the fuel cell. The fuel cell test bench 40 is used to install and fix fuel cells for testing, and provides physical interfaces for external pipelines and the test environment. The partition acquisition device 50 is installed inside the fuel cell at the projection position corresponding to the flow field reaction area, and is located between the current collector and the bipolar plate. The partition acquisition device 50 includes a test electrode sampling plate 51 and a reference electrode sampling plate 52. Both the test electrode sampling plate 51 and the reference electrode sampling plate 52 have multiple partition structures that are insulated from each other, and synchronously acquire the excitation and response signals of different spatial regions of the fuel cell under corresponding operating conditions. The data acquisition unit 60 is communicatively connected to the signal output terminal of the partition acquisition device 50, and synchronously receives signals from the test electrode sampling board 51 and the reference electrode sampling board 52. The data processing unit 70 is communicatively connected to the data acquisition unit 60. It parses the synchronization signal acquired by the data acquisition unit 60 and generates physical performance indicators for each partition through calculation.

[0025] See attached document Figure 2 This invention provides a method for synchronous detection of multi-zone membrane electrode parameters in a fuel cell, comprising the following steps: S100, construct a dual-condition test process, set up membrane electrode parameter detection condition and AC impedance detection condition, configure the membrane electrode parameter detection condition and AC impedance detection condition to be independent of each other in time, configure the membrane electrode parameter detection condition and AC impedance detection condition to share the same partition acquisition device 50, the same set of partition channel numbers and the same spatial coordinate mapping relationship, configure the partition parameters obtained under the membrane electrode parameter detection condition and AC impedance detection condition to be correlated and analyzed at the same physical location; S200, establish system hardware connection relationship, and fix the fuel cell with the test electrode sampling plate 51 and the reference electrode sampling plate 52 embedded in it to the fuel cell test bench 40. S300, execute the membrane electrode parameter detection mode, control the gas supply system 10 to introduce pure hydrogen to the anode side of the fuel cell, and simultaneously introduce pure nitrogen to the test electrode side of the fuel cell, control the excitation signal source 20 to apply a DC current excitation or DC voltage excitation of a set amplitude to the fuel cell, use the data acquisition unit 60 to synchronously acquire the DC excitation and its response signal output from each partition unit in the test electrode sampling plate 51 and the reference electrode sampling plate 52, extract the response data of each partition, and calculate the membrane electrode parameters of each partition through the data processing unit 70. The extracted membrane electrode parameters include the double layer capacitance, hydrogen permeation current density, short circuit resistance and electrochemical active area of ​​each partition. S400, execute AC impedance detection mode, connect the fuel cell equipped with the partition acquisition device 50 to the electronic load 30, adjust the working mode of the gas supply system 10 and keep hydrogen gas flowing through the anode side of the fuel cell, switch the gas path on the test electrode side of the fuel cell and introduce air, control the excitation signal source 20 to apply AC voltage excitation or AC current excitation within a set frequency range to the fuel cell, and use the data acquisition device 60 to synchronously acquire the AC excitation and its response signal output by each partition unit in the partition acquisition device 50. S500 generates spatial distribution detection results. The data processing unit 70 performs numerical calculations on the signals acquired under the membrane electrode parameter detection condition and the AC impedance detection condition to obtain the electrochemical active area, double layer capacitance, hydrogen permeation current density, short-circuit resistance and AC impedance value of each independent partition, and outputs electrochemical parameter distribution data covering all spatial partitions.

[0026] See attached document Figure 3 In a specific implementation, step S100 provided by the present invention includes the following steps: S101, during the test preparation phase, the partition acquisition device 50 is assembled between the current collector and bipolar plate inside the fuel cell and a mechanical fastening force is applied to the fuel cell body, so that the partition acquisition device 50 and the internal components of the fuel cell are in physical contact and the corresponding assembly stress is maintained.

[0027] S102, the test control sequence is set by the data processing unit 70, and the overall detection process is divided into two independent execution cycles in the time dimension according to the set time nodes. The two execution cycles are assigned to the membrane electrode parameter detection condition and the AC impedance detection condition respectively, and the membrane electrode parameter detection condition and the AC impedance detection condition are controlled to run sequentially or independently.

[0028] S103, configure corresponding equipment coordination logic for the two divided execution cycles. In the execution cycle corresponding to the membrane electrode parameter detection condition, control the gas supply system 10 to output nitrogen and hydrogen to the fuel cell test electrode side and reference electrode side respectively, and disconnect the external circuit where the electronic load 30 is located. Configure the main circuit to retain only the excitation signal source 20 and the sampling circuit, and output a DC excitation signal from the excitation signal source 20. In the execution cycle corresponding to the AC impedance detection condition, control the gas supply system 10 to switch to output air to the fuel cell test electrode side and keep outputting hydrogen to the reference electrode side. Turn on the external circuit where the electronic load 30 is located to maintain the steady-state discharge boundary of the fuel cell, and superimpose an AC perturbation excitation signal onto the main circuit from the excitation signal source 20 or the electronic load 30 with impedance testing function.

[0029] S104, the physical installation area corresponding to each hardware acquisition channel in the partition acquisition device 50 is mapped to the corresponding spatial coordinate identifier. A one-to-one correspondence between the acquisition channel number and the spatial coordinate identifier is established in advance. During the execution of the membrane electrode parameter detection mode and the AC impedance detection mode, the data acquisition unit 60 acquires the excitation and response signals respectively, and the data processing unit 70 binds the excitation and response signals with the corresponding spatial coordinate identifier to generate the underlying mapping data with physical position attributes.

[0030] During the execution of the above steps, the data processing unit 70 schedules the gas path valve action and circuit relay switching by sending control command frames containing timing tags to external devices. The membrane electrode parameter detection condition is in a non-reactive environment and receives a DC excitation signal, while the AC impedance detection condition is in a power generation reaction environment and receives an AC excitation signal. The two types of detection processes are distributed in independent time axis intervals and cooperate with the same set of hardware acquisition channels. The electrochemical response process inside the fuel cell is configured to be independently analyzed in the form of time-division multiplexing. The voltage and current signals acquired by the data acquisition unit 60 have a unified spatial reference system.

[0031] S201, when assembling the fuel cell for testing, the end plate, insulating plate, current collector plate, partition acquisition device 50, bipolar plate and membrane electrode are assembled sequentially from the outside to the inside. The test electrode sampling plate 51 and the reference electrode sampling plate 52 in the partition acquisition device 50 are symmetrically embedded between the corresponding current collector plates and bipolar plates on both sides of the membrane electrode. The conductive surface of the test electrode sampling plate 51 is configured to be in contact with the non-flow field of the bipolar plate on the test electrode side, and the conductive surface of the reference electrode sampling plate 52 is in contact with the non-flow field of the bipolar plate on the reference electrode side, and the internal sampling hardware and the gas phase flow field distribution area of ​​the fuel cell are kept in an overlapping state in physical space projection.

[0032] S202, based on the geometric dimensions of the internal reaction region of the fuel cell, the sampling areas of the test electrode sampling plate 51 and the reference electrode sampling plate 52 are divided into matrix-type insulating partitions with m rows and n columns. Each insulating partition is electrically isolated from the others by an insulating dielectric layer. m and n are both positive integers greater than or equal to 2. Each independently led-out insulating partition together forms a multi-node spatial acquisition network corresponding to the reaction area of ​​the entire flow field.

[0033] See attached document Figure 4 In a specific implementation, step S300 provided by the present invention includes the following steps: S301, under the condition of membrane electrode parameter detection, the gas supply system 10 is controlled to introduce pure nitrogen into the test electrode side of the fuel cell and pure hydrogen into the reference electrode side, and the excitation signal source 20 is controlled to continuously apply at least four constant DC current excitation signals of different amplitudes to the fuel cell. When DC voltage excitation is used, the data acquisition unit 60 synchronously acquires the response current of the corresponding partition and converts it into equivalent excitation data. The data acquisition unit 60 synchronously acquires the electrochemical response curves output by each insulating partition corresponding to the spatial coordinates of the test electrode sampling plate 51 and the reference electrode sampling plate 52. Based on the electrochemical physical characteristics dominated by the double-layer charging and discharging and hydrogen permeation behavior under the test conditions, the data processing unit 70 performs data truncation operations on each response curve, extracts the response voltage data and the corresponding response time data within the preset feature interval to form a feature data subset. In this embodiment, the value range of the preset feature interval is 0.4V to 0.6V.

[0034] S302, the entire insulation zone establishes a multivariable charge conservation equation based on the physical mechanism that the input excitation charge equals the sum of the double-layer charging charge and the hydrogen permeation charge, as well as the sum of the short-circuit charge and the hydrogen desorption charge: ; ; ; ; In the formula, i The current excitation spatial distribution matrix (the remaining matrices are as follows) i (Expanded as shown) Q H This is the spatial distribution matrix of hydrogen desorption charge; C dl This is the spatial distribution matrix of the double-layer capacitance; S e This is the spatial distribution matrix of short-circuit conductance; V To test the spatial distribution matrix of the potential difference at the electrode interface; V 0 represents the spatial distribution matrix of the initial interface potential difference of the test electrode;U 0 represents the initial response voltage spatial distribution matrix; U The response voltage spatial distribution matrix; R ohm The spatial distribution matrix of ohmic impedance; ΔU is the spatial distribution matrix of the initial excitation voltage jump value; ⊙ is the Hadamard product, representing the element-wise multiplication of the matrix; Hadamard division represents element-wise division of a matrix.

[0035] For any single insulation zone, the data processing unit 70 processes data from the first to the second... The feature data subset corresponding to the constant DC current excitation is processed; using the response time corresponding to each response as the integration interval, time integration is performed on the local excitation current data and local response voltage data respectively, and the obtained integral values ​​are divided by the corresponding response time to obtain the local excitation current time average and local response voltage time average; the reciprocal operation is performed on each response time to obtain the response time reciprocal data; the response voltage jump value in the initial stage of each excitation is extracted, and the local response voltage is corrected by ohmic voltage drop according to the response voltage jump value to obtain the test electrode interface potential difference and its initial value; the difference between the test electrode interface potential difference and its initial value is divided by the corresponding response time to obtain the average change rate of the test electrode interface potential difference; the local excitation current time average, local response voltage time average, response time reciprocal data, and test electrode interface potential difference average change rate are constructed into an input excitation column vector and feature coefficient matrix according to a preset order, and substituted into the set matrix equations: ; ; ; ; In the formula, For the reason of multiple times ( k A column vector of average input excitation time values ​​composed of constant DC current excitation signals of different amplitudes (times); It is a matrix of characteristic coefficients composed of the reciprocal of the response time for each response, the average rate of change of the potential difference at the test electrode interface, the constant term, and the average value of the response voltage time. The vector of parameters to be solved consists of local double-layer capacitance, short-circuit conductance, hydrogen permeation current density, and hydrogen desorption charge.

[0036] Data processing unit 70 pairs of matrices Perform least squares operation and output the basic electrochemical characteristic values ​​covering the four core parameters, and obtain the short-circuit resistance of the corresponding partition by taking the reciprocal of the short-circuit conductance.

[0037] S303, extracting local hydrogen desorption charge And combine the target partition physical platinum load parameters stored in the data processing unit 70 to construct a parameter transformation operator, and execute the expression: ; In the formula, For the electrochemically active area parameters of the corresponding insulation zone; The local hydrogen desorption charge is obtained by solving the matrix equation for the corresponding insulation zone; This represents the preset theoretical saturated adsorption charge constant of a monolayer platinum surface. In this embodiment, the value of the theoretical saturated adsorption charge constant of a monolayer platinum surface is 210. ; The amount of platinum load pre-stored for the target insulation zone.

[0038] The data processing unit 70 converts the microscopic charge value extracted from the response data into a physical active area parameter characterizing the actual participation of the catalyst in the electrochemical reaction based on numerical calculation logic, and stores it in the corresponding hardware acquisition channel data buffer area.

[0039] S304, the characteristic parameters of all insulating zones within the sensing area of ​​the test electrode sampling plate 51 are arranged into a spatial arrangement matrix according to physical topological coordinates. An array operation based on element-wise division is performed on the hydrogen desorption charge matrix covering the global spatial dimension and the platinum loading matrix in the corresponding coordinates. The underlying algebraic operation library is called to execute the expression: ; In the formula, This is the spatial distribution matrix of the electrochemical active area; This is the spatial distribution matrix of hydrogen desorption charge in each partition; The Hadamard division operator for performing element-wise division of a matrix; This is the preset theoretical saturated adsorption charge constant for a single-layer platinum surface; This is the spatial distribution matrix of platinum loading.

[0040] The underlying algebraic operation library outputs multidimensional parameter global distribution characteristic state values ​​covering all spatial dimensions through concurrent processing operations of matrix arrays, and completes the synchronous solution process of parameters in each partition.

[0041] See attached document Figure 5 In specific implementation, steps S400 and S500 provided by the present invention include the following steps: S401, after completing the synchronous calculation of multi-zone membrane electrode parameters, performs a test condition conversion operation, controls the gas supply system 10 to adjust the fluid distribution valve to switch the nitrogen gas introduced to the fuel cell test electrode side to air and maintain the continuous supply of pure hydrogen gas to the reference electrode side, controls the main circuit electrical connection of the fuel cell test bench 40 to perform hardware reconstruction and switches to the working mode of the electronic load 30, establishes the continuous discharge test boundary environment of the fuel cell and configures the fuel cell to switch from the physical condition of internal parameter detection to the normal power generation output operation state.

[0042] S402, based on the power generation output operating state, the electronic load 30 maintains the steady-state DC discharge operating point of the fuel cell. A perturbation AC excitation signal within a set frequency band is superimposed onto the fuel cell main circuit by the excitation signal source 20 or the electronic load 30 with impedance testing function. The perturbation amplitude of the perturbation AC excitation signal is configured according to the linear system assumption of impedance measurement, and the measurement frequency band is set. In this embodiment, the perturbation amplitude ranges from 5% to 10% of the steady-state DC discharge current. The configured measurement frequency band covers the high-frequency band for obtaining the high-frequency real intercept and the frequency band characterizing the mid-to-low frequency response. The data acquisition unit 60 synchronously acquires the time-domain voltage and current timing signals returned from each insulation zone in the test electrode sampling board 51 and the reference electrode sampling board 52. The data processing unit 70 uses fast Fourier transform, sine fitting, or phase-locked demodulation to perform frequency domain conversion operations on the time-domain signal array of each zone to generate complex-domain frequency-domain voltage and current data, and executes the expression: ; In the formula, The frequency domain complex impedance generated analytically for the corresponding insulation zone at a specific excitation frequency; The frequency domain complex voltage generated by the fast Fourier transform of the corresponding insulation zone; The frequency domain complex current generated by the fast Fourier transform for the corresponding insulation zone; The angular frequency is the perturbation AC excitation signal superimposed on the main circuit of the fuel cell.

[0043] The data processing unit 70 performs a frequency node-based sequence integration operation to extract local AC impedance spectrum data covering the entire measurement frequency band from high frequency to low frequency.

[0044] S501, extract the spatial distribution matrix of electrochemical active area, spatial distribution matrix of short-circuit resistance, spatial distribution matrix of hydrogen permeation current density, spatial distribution matrix of double layer capacitance, and AC impedance spectrum data corresponding to each insulation partition generated by the data processing unit 70. Based on the preset matrix row and column numbers on the test electrode sampling plate 51 and the reference electrode sampling plate 52, call the corresponding physical topology coordinate information. Perform array alignment operation based on spatial coordinate nodes on the extracted multidimensional electrochemical feature parameters to construct a multidimensional spatial fusion dataset covering internal reaction features, hardware insulation features, and AC frequency domain impedance characteristics. Map the matrix values ​​of each dimension to the spatial distribution state topology that matches the actual flow field geometry of the fuel cell.

[0045] S502, based on the generated multi-dimensional spatial fusion dataset, extract the electrochemical feature parameters corresponding to each physical coordinate node, and in the data processing unit 70, calculate the deviation difference between the feature parameters under different spatial topological regions and the benchmark feature data and perform a comparison operation based on a preset deviation threshold. The preset deviation threshold is determined by the benchmark feature data measured under the same working condition under the calibrated health state combined with the set fault tolerance floating ratio. In this embodiment, the tolerance floating ratio is set to a range of 8% to 10%. The deviation state of the hydrogen permeation current density exceeding the preset deviation threshold is used as the physical criterion for mechanical damage to the proton exchange membrane. The decay of the electrochemical active area is used as the physical criterion for the decline in catalyst performance. An engineering diagnostic coordinate report is output, indicating the local catalyst performance decay area and the location of mechanical damage risk of the proton exchange membrane inside the fuel cell.

[0046] To aid in understanding the technical solution of this invention, the following provides an application example and test example of a method and apparatus for synchronous detection of multi-zone membrane electrode parameters in fuel cells.

[0047] Application Examples: The test subject was a proton exchange membrane fuel cell with an internal partitioned acquisition device 50, divided into 2 rows and 2 columns, containing 4 independent partitions, and an active area of ​​25 cm². 2 The preset platinum loading is 0.4 mg / cm³. 2 The system presets the theoretical saturated adsorption charge constant of a single-layer platinum surface to be 210. .

[0048] During the membrane electrode parameter detection operation, the gas supply system 10 introduces pure nitrogen gas to the test electrode side and pure hydrogen gas to the reference electrode side, while the excitation signal source 20 sequentially applies 4 mA / cm² to the fuel cell. 2 6mA / cm 2 8mA / cm 2 and 10mA / cm 2A total of four constant DC current excitations were performed. The data acquisition unit 60 simultaneously acquired the response curves of the four zones. The data processing unit 70 extracted the voltage data and response time data of each zone from 0.4V to 0.6V. The data processing unit 70 performed time integration and reciprocal calculation on the data extracted from zone 1, and extracted the jump value of the initial response voltage to calculate the potential difference at the test electrode interface. The data processing unit 70 constructed a multivariable charge conservation equation system with the four input current values ​​as the input excitation column vector and the voltage-time integral, the potential difference at the test electrode interface, and the reciprocal of the response time as the characteristic coefficient matrix. The data processing unit 70 performed least squares operation on the characteristic coefficient matrix to solve for the unknown vector.

[0049] The local hydrogen desorption charge in region 1 was calculated to be 8.85 mC / cm² based on the matrix solution. 2 The data processing unit 70 will process 8.85 mC / cm 2 Divide by 210 and 0.4 mg / cm 2 The electrochemical active area of ​​region 1 was found to be 10.54 m². 2 / g, the data processing unit 70 simultaneously calculates the basic parameters of zones 2, 3 and 4.

[0050] The system switches the AC impedance detection mode to introduce air into the test electrode side. The electronic load 30 intervenes to maintain the fuel cell in a steady-state DC discharge state of 10A. The excitation signal source 20 adds an AC perturbation signal with a peak value of 0.5A to the main circuit for frequency domain sweep. The data processing unit 70 performs fast Fourier transform on the time domain fluctuation signals of the four partitions to extract the frequency domain complex impedance. The data processing unit 70 analyzes the ohmic impedance, charge transfer impedance and mass transfer impedance of the first partition as 65mΩ·cm², 96mΩ·cm² and 70mΩ·cm², respectively.

[0051] The system is set to a baseline of 20m² for the electrochemically active area under calibrated healthy conditions. 2 / g and with a fault tolerance float ratio of 10%, the system will be 10.54m 2 After performing a comparison operation between / g and the benchmark and the tolerance range, an engineering diagnostic coordinate report is output. The engineering diagnostic coordinate report indicates that there is local catalyst performance degradation in zone 1.

[0052] Test example: The experimental subject was a single-cell proton exchange membrane fuel cell with 16 independently partitioned data acquisition devices (4 rows and 4 columns) internally implanted. Before testing, the fuel cell was first calibrated under healthy conditions without any artificial defects to obtain healthy reference data on the electrochemical active area and hydrogen permeation current density of each partition. The corresponding deviation thresholds were then determined by combining the normal spatial dispersion under healthy conditions, repeatability measurement errors, and preset safety margins. Subsequently, mechanical needle-puncture damage defects were applied to the proton exchange membrane location corresponding to partition 6, and catalyst layer stripping was performed on the membrane electrode area corresponding to partition 11 to create defect verification objects.

[0053] The defect verification object was tested using both the multi-zone detection method of this invention and the traditional whole cell detection method. The experimental steps were as follows: establishing the system hardware connection relationship and spatial mapping relationship; the excitation signal source 20 executed the membrane electrode parameter detection mode and the data acquisition unit 60 acquired the response voltage curves of 16 zones; the system switched to the AC impedance detection mode and the data acquisition unit 60 acquired the time-domain AC signals of 16 zones; the data processing unit 70 calculated and output the electrochemical active area, short-circuit resistance, double-layer capacitance, hydrogen permeation current density, ohmic impedance, charge transfer impedance, and mass transfer impedance of all zones; the control group used external testing equipment to perform global cyclic voltammetry, global linear voltammetry, and global electrochemical impedance spectroscopy to obtain the overall average data; the calculation results are shown in the table below: Calculation data table of multidimensional electrochemical characteristic spatial distribution of fuel cells in 16 zones From the table above and appendix Figure 6 and attached Figure 7 It can be seen that the electrochemically active area of ​​the healthy zone is between 18.14 and 20.95 m². 2 The hydrogen permeation current density ranges from 7.62 to 8.36 mA / cm² within the range of / g. The mean electrochemical active area and hydrogen permeation current density measured under healthy conditions are 19.80 m². 2 / g and 8.30mA / cm², using the mean of health state parameters as the standard for deviation threshold calculation, with a tolerance fluctuation ratio of 10%, the lower limit of the health threshold for electrochemical active area and the upper limit of the health threshold for hydrogen permeation current density are 17.82m. 2 / g and 9.13mA / cm². The calculated hydrogen permeation current density for zone 6 is 15.72mA / cm², which is higher than the preset deviation threshold. The calculated electrochemical active area for zone 11 is 5.67m². 2 / g and below the preset deviation threshold, the average global electrochemical active area of ​​the control group was 18.30m.2 Both the / g and the global average hydrogen permeation current density of 8.95 mA / cm² are within the non-alarm range and no defect coordinates are output. In contrast, the multi-zone detection results of this invention identify an abnormal increase in the hydrogen permeation current density of zone 6 and an abnormal decrease in the electrochemical active area of ​​zone 11, and output spatial coordinates consistent with the preset artificial defect locations. This shows that traditional whole cell parameters are affected by the spatial averaging effect, which may mask local anomalies, while this invention can achieve parameter identification and spatial location of internal local defects.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for synchronous detection of multi-zone membrane electrode parameters in a fuel cell, characterized in that, include: A dual-condition test process was constructed, and the membrane electrode parameter detection condition and the AC impedance detection condition were set to be executed sequentially or separately, while sharing the same partition acquisition device and the same spatial coordinate mapping relationship. Establish system hardware connection relationships and connect the fuel cell with the embedded partition acquisition device to the test system; The membrane electrode parameter detection condition is executed by introducing pure nitrogen gas into the test electrode side of the fuel cell and pure hydrogen gas into the reference electrode side, applying a DC excitation signal, and simultaneously acquiring the DC excitation and response signals of each partition in the partition acquisition device and calculating the membrane electrode parameters of each partition. When performing the AC impedance detection operation, the test electrode side of the fuel cell is switched to be vented with air and the reference electrode side is kept vented with pure hydrogen. A perturbation AC excitation signal is applied, and the AC excitation and response signals of each partition are acquired simultaneously and the local AC impedance spectrum data is extracted. The spatial distribution detection results are generated, and the membrane electrode parameters of each partition are fused with the local AC impedance spectroscopy data to output electrochemical parameter distribution data covering the entire spatial partition.

2. The method for synchronous detection of multi-zone membrane electrode parameters in a fuel cell according to claim 1, characterized in that, The steps for performing the membrane electrode parameter detection operation include: At least four constant DC current excitation signals of different amplitudes are continuously applied to the fuel cell, and the electrochemical response curves of each partition corresponding to the spatial coordinates are acquired simultaneously. Extract the excitation current and response voltage data and the corresponding response time data within the preset feature range to form a feature data subset; Based on the physical mechanism that the excitation charge is equal to the sum of the electric double layer capacitance charging charge, hydrogen permeation charge, short-circuit charge, and hydrogen desorption charge, a multivariable charge conservation equation is established. The feature data subset is processed, and the response time corresponding to each response is used as the integration interval. Time integration is performed on the local excitation current data and the local response voltage data respectively, and the obtained integral values ​​are divided by the corresponding response time to obtain the local excitation current time average and the local response voltage time average. Perform the reciprocal operation on each response time to obtain the reciprocal data of the response time; extract the response voltage jump value at the initial stage of each excitation, and perform ohmic voltage drop correction on the local response voltage based on the response voltage jump value to obtain the potential difference at the test electrode interface and its initial value. The average rate of change of the test electrode interface potential difference is obtained by dividing the difference between the test electrode interface potential difference and its initial value by the corresponding response time. The average local excitation current over time, the average local response voltage over time, the reciprocal of the response time, and the average rate of change of the potential difference at the test electrode interface are used to construct an input excitation column vector and a characteristic coefficient matrix in a preset order. These are then substituted into a set of matrix equations, and least squares operations are performed to obtain the characteristic values ​​of basic electrochemical parameters covering double-layer capacitance, short-circuit resistance, hydrogen permeation current density, and hydrogen desorption charge.

3. The method for synchronous detection of multi-zone membrane electrode parameters in a fuel cell according to claim 2, characterized in that, The steps for calculating the membrane electrode parameters for each partition include: The local hydrogen desorption charge is extracted and the electrochemical active area of ​​the corresponding partition is calculated by combining it with the platinum loading of the target partition. The fundamental electrochemical eigenvalues ​​of all partitions are arranged into a spatial arrangement matrix based on physical topological coordinates; An array operation based on element-wise division is performed on the hydrogen desorption charge matrix covering the global spatial dimension and the platinum loading matrix in the corresponding coordinates to output a global electrochemical active area matrix covering all spatial dimensions and complete the synchronous calculation process of parameters for each partition.

4. The method for synchronous detection of multi-zone membrane electrode parameters in a fuel cell according to claim 1, characterized in that, The steps for performing the AC impedance detection operation include: The electronic load is controlled to maintain the steady-state DC discharge operating point of the fuel cell, and a micro-perturbation AC excitation signal within a set frequency band is superimposed onto the main circuit of the fuel cell. Synchronously acquire the time-domain voltage timing signal and time-domain current timing signal collected from each partition; The frequency domain transformation operation is performed on the time domain signal array of each partition using fast Fourier transform, sine fitting or phase-locked demodulation to generate frequency domain voltage data and frequency domain current data in the complex domain; Perform frequency node-based sequence integration operations to extract local AC impedance spectrum data covering the entire measurement frequency band from high frequency to low frequency.

5. The method for synchronous detection of multi-zone membrane electrode parameters in a fuel cell according to claim 1, characterized in that, The steps for generating spatial distribution detection results include: Based on the preset matrix row and column numbers, the corresponding physical topology coordinate information is called, and an array alignment operation based on spatial coordinate nodes is performed on the extracted membrane electrode parameters and the local AC impedance spectrum data. A multidimensional spatial fusion dataset covering internal reaction characteristics, hardware insulation characteristics, and AC frequency domain impedance characteristics is constructed, and the numerical values ​​of each dimension matrix are mapped to a spatial distribution state topology that matches the actual flow field geometry of the fuel cell. The electrochemical characteristic parameters corresponding to each physical coordinate node are extracted, the deviation difference between them and the benchmark characteristic data is calculated, and a comparison operation based on a preset deviation threshold is performed. The preset deviation threshold is determined by the benchmark characteristic data measured under the same working conditions under the calibrated healthy state and the set fault tolerance floating ratio. An engineering diagnostic coordinate report is output, indicating the location of local catalyst performance decay area, abnormal water and heat distribution area and mechanical damage risk of proton exchange membrane inside the fuel cell.

6. The method for synchronous detection of multi-zone membrane electrode parameters in a fuel cell according to claim 1, characterized in that, The steps for constructing the dual-condition test procedure include: The physical installation area corresponding to each hardware acquisition channel in the partition acquisition device is mapped to the corresponding spatial coordinate identifier, and a one-to-one correspondence between the acquisition channel number and the spatial coordinate identifier is established in advance. Sending control command frames containing timing tags to external devices schedules the operation of gas path valves and the switching of circuit relays, controlling the membrane electrode parameter detection mode and the AC impedance detection mode to operate sequentially or individually.

7. A device for synchronously detecting multi-zone membrane electrode parameters of a fuel cell, characterized in that, The apparatus for synchronously detecting the parameters of a multi-zone membrane electrode assembly in a fuel cell according to any one of claims 1 to 6 includes: The gas supply system is located at the gas input end of the fuel cell and switches between supplying different types of test gases to the test electrode side and the reference electrode side of the fuel cell according to the test command. The excitation signal source is electrically connected to the fuel cell and is used to output DC excitation signals and AC perturbation excitation signals; An electronic load, connected to the main circuit of the fuel cell, is used to maintain the steady-state discharge boundary of the fuel cell; A partitioned acquisition device, installed inside the fuel cell at a projection position corresponding to the flow field reaction region, has multiple mutually insulated partitioned structures for synchronously acquiring excitation and response signals from different spatial regions; a data acquisition unit, communicatively connected to the signal output terminal of the partitioned acquisition device, is used to synchronously receive voltage and current change signals. The data processing unit is connected to the data acquisition unit and is used to parse the synchronization signal and perform matrix equation calculations and array operations through the underlying algebra operation library, outputting the global distribution characteristic state values ​​of multidimensional parameters.

8. The synchronous detection device for multi-zone membrane electrode parameters of a fuel cell according to claim 7, characterized in that, The partitioned acquisition device includes a test electrode sampling plate and a reference electrode sampling plate. The conductive surface of the test electrode sampling plate is attached to the non-flow field of the bipolar plate on the test electrode side, and the conductive surface of the reference electrode sampling plate is attached to the non-flow field of the bipolar plate on the reference electrode side. The sampling areas of the test electrode sampling plate and the reference electrode sampling plate are divided into matrix-type insulating partitions with m rows and n columns. Each insulating partition is electrically isolated from the others by an insulating dielectric layer, where m and n are both positive integers greater than or equal to 2.

9. The synchronous detection device for multi-zone membrane electrode parameters of a fuel cell according to claim 7, characterized in that, Each insulating partition of the test electrode sampling plate serves as a local excitation current acquisition partition, and is connected to the current acquisition channel of the data acquisition device through a corresponding independent signal terminal, for acquiring the local excitation current signal within the corresponding spatial partition of the fuel cell. Each insulating partition of the reference electrode sampling board and each insulating partition corresponding to the spatial coordinates in the test electrode sampling board form a local differential voltage sampling pair. Each local differential voltage sampling pair is connected to the differential voltage acquisition channel of the data acquisition device to acquire the local response voltage signal between the reference electrode sampling board and the test electrode sampling board in the corresponding spatial partition. The data acquisition unit is used to synchronously acquire the local excitation current signal and the local response voltage signal of each spatial partition, and transmit the local excitation current signal and the local response voltage signal to the data processing unit according to the corresponding matrix row and column coordinates.

10. The synchronous detection device for multi-zone membrane electrode parameters of a fuel cell according to claim 7, characterized in that, The data processing unit has an algebraic operation library built into its underlying layer. This library is used to perform element-wise division of spatially arranged matrices and least squares operations on system of equations matrices through concurrent processing of matrix arrays.

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