CN109828216A

CN109828216A - Improve the device and method of fuel cell subregion electrochemical impedance spectroscopy accuracy of measurement

Info

Publication number: CN109828216A
Application number: CN201910092241.6A
Authority: CN
Inventors: 林瑞; 刘登程; 韩立行
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2019-01-30
Filing date: 2019-01-30
Publication date: 2019-05-31
Anticipated expiration: 2039-01-30
Also published as: CN109828216B

Abstract

The present invention relates to a kind of device and methods for improving fuel cell subregion electrochemical impedance spectroscopy accuracy of measurement, including DC power supply, for measuring the electrochemical workstation of fuel cells impedance, circuit load and for by the PCB unit of anode flow field selective connection electrochemical workstation or circuit load, the anode of DC power supply is respectively with electrochemical workstation to electrode, the cathode flow field of fuel cell and the end the A connection of circuit load, the cathode of DC power supply is connect with the working electrode of electrochemical workstation and PCB unit respectively, one end of PCB unit and the anode flow field of fuel cell connect, other end selectivity is connect with the end B of the working electrode of electrochemical workstation or circuit load.Compared with prior art, the present invention passes through a DC power supply in parallel, so that fuel cell can guarantee that it has certain electric current being not switched on load, will not become open-circuit condition, guarantees that current distribution is still consistent in test process, keeps result more acurrate.

Description

Improve the device and method of fuel cell subregion electrochemical impedance spectroscopy accuracy of measurement

Technical field

The present invention relates to field of fuel cell technology, and in particular to a kind of raising fuel cell subregion electrochemical impedance spectroscopy survey Measure the device and method of accuracy.

Background technique

Electrochemical impedance spectroscopy is the effective ways for studying Proton Exchange Membrane Fuel Cells, by the way that fuel cell is seen as one Black smoker measures its frequency domain response and the electrochemistry meaning using equivalent-circuit component, can analyze the operating of entire battery State, such as kinetics of electrode process, electric double layer and diffusion and electrode material, solid electrolyte, conducting polymer, corrosion protection Mechanism etc..

However in fuel battery inside, the reaction of different zones is differentiated, and Local electrochemical impedance spectrum (Local EIS researcher) can then be helped to understand the reaction condition of inside battery partial region.This technology is by applying printed circuit Plate realizes, its influence to fuel cell operation operating condition is very little.

EIS experiment generally measures under battery operation operating condition.In the process of running, battery and load connect, inside battery The region to react can generate electric current.In traditional Local electrochemical impedance spectrum sensing equipment, some region is measured When EIS, which can disconnect with load, cause the electric current in the region to become 0, be equivalent to open circuit；If the subregion does not turn off Connection, may result in test result cannot represent the subregion actual conditions.The survey of requirement cannot be reached in measurement in this way Trial work condition will affect current density distribution and the reaction of each region hydrogen and oxygen of entire battery etc., the result of last test Also just inaccurate.

Summary of the invention

It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art and provide a kind of raising fuel cells The device and method of subregion electrochemical impedance spectroscopy accuracy of measurement.

The purpose of the present invention can be achieved through the following technical solutions: a kind of raising fuel cell subregion electrochemical impedance The device of spectrometry accuracy, the fuel cell to be measured include the cathode flow field, membrane electrode and anode flow field being sequentially overlapped, The device includes DC power supply, the electrochemical workstation for measuring fuel cells impedance, circuit load and is used for anode Flow field selective connection electrochemical workstation or the PCB unit of circuit load, the electrochemical workstation includes reference electrode, right Electrode and working electrode, the DC power supply anode respectively with the cathode stream to electrode, fuel cell of electrochemical workstation Field and the connection of the end A of circuit load, the cathode of the DC power supply are mono- with the working electrode of electrochemical workstation and PCB respectively The anode flow field of member connection, one end of the PCB unit and fuel cell connects, other end selectivity and electrochemical workstation Working electrode or circuit load the end B connection.The present invention passes through a DC power supply in parallel, even if so that fuel cell Being not switched on load also can guarantee that it has certain electric current, will not become open-circuit condition, guarantee that current distribution is still in test process It is so consistent, keep result more acurrate.

The anode flow field of the fuel cell is divided into multiple independent test subregions and multiple common subregions.

The PCB unit includes multiple single-pole double-throw switch (SPDT)s, multiple regular taps and multiple current sensors, the list The a terminals and test piecewise connection of double-pole double throw switch, the b terminals of single-pole double-throw switch (SPDT) and the work electricity of electrochemical workstation Pole connection, the c terminals of single-pole double-throw switch (SPDT) are connect with circuit load, and in the connecting line of the c terminals and circuit load One current sensor of upper setting, the common subregion are connect with circuit load, and in the connecting line of common subregion and circuit load One current sensor of upper setting, the common subregion are connected by the working electrode of regular tap and electrochemical workstation.

When the electrochemical impedance time spectrum for measuring a certain test subregion, by the corresponding single-pole double-throw switch (SPDT) of the test subregion to be measured Switch be allocated to b terminals and connect the working electrode of test subregion and electrochemical workstation to be measured, remaining test subregion is corresponding The switch of single-pole double-throw switch (SPDT) be allocated to c terminals, the regular tap disconnects；

When measurement fuel cell entirety electrochemical impedance time spectrum, all switches for testing the corresponding single-pole double-throw switch (SPDT) of subregion C terminals are allocated to, the regular tap is connected.

The reference electrode of the electrochemical workstation and test piecewise connection to be measured.

The end A of the circuit load and the cathode flow field of fuel cell connect.

A kind of raising fuel cell subregion electrochemical impedance spectroscopy accuracy of measurement carried out using device as described above Method, comprising the following steps:

(1) first DC power supply is not incorporated to circuit, so that all test subregions, common subregion is connected with circuit load, i.e., All single-pole double-throw switch (SPDT)s are at the end c.Subregion is tested using the connected direct read response of current sensor of each test subregion On subregion electric current, and record to be used to subsequent step；

(2) so that a certain test subregion is connected with DC power supply, that is, convey the B termination of the connected single-pole double-throw switch (SPDT) of the subregion It is logical.It maintains single-pole double-throw switch (SPDT) corresponding to other test subregions to be connected with the end c, maintains regular tap to be in an off state, select Use current value be step (1) measure and the current value of nominative testing subregion that records as DC power supply input current and connect Enter circuit and forms device；

(3) successively switch test subregion to be measured, and by switching corresponding single-pole double-throw switch (SPDT) to the end B, maintain Other single-pole double-throw switch (SPDT)s are in C-terminal, and regular tap is in open circuit and loads, and the output current value of DC power supply is set as first The current value of the test subregion that step is surveyed and recorded, and record using electrochemical workstation the impedance value of the subregion, then it can be complete At the subregion electrochemical alternate impedance spectrum of all test subregions.

Compared with prior art, the beneficial effects of the present invention are embodied in:

By a DC power supply in parallel, so that fuel cell can guarantee that it has centainly being not switched on load Electric current, will not become open-circuit condition, guarantee that current distribution is still consistent in test process, keeps result more acurrate.

Detailed description of the invention

Fig. 1 is the connection schematic diagram of test device of the present invention；

Fig. 2 is the separation schematic diagram in 1 Anodic flow field of embodiment；

Fig. 3 is each zone current density profile under initial operating condition；

Fig. 4 is each zone current density profile when test subregion to be measured is the region G4；

Fig. 5 be in comparative example when test subregion to be measured is the region G4 each zone current density profile.

Wherein, 1 is DC power supply, and 2 be electrochemical workstation, and 21 be reference electrode, and 22 is, to electrode, 23 are work electricity Pole, 3 be fuel cell, and 31 be cathode flow field, and 32 be membrane electrode, and 33 be anode flow field, and 331 be test subregion, and 332 be common point Area, 4 be circuit load, and 5 be PCB unit, and 51 be single-pole double-throw switch (SPDT), and 52 be regular tap, and 53 be current sensor.

Specific embodiment

It elaborates below to the embodiment of the present invention, the present embodiment carries out under the premise of the technical scheme of the present invention Implement, the detailed implementation method and specific operation process are given, but protection scope of the present invention is not limited to following implementation Example.

Embodiment 1

A kind of device improving fuel cell subregion electrochemical impedance spectroscopy accuracy of measurement, structure is as shown in Figure 1, to be measured Fuel cell 3 include the cathode flow field 31, membrane electrode 32 and the anode flow field 33 that are sequentially overlapped, the device include DC power supply 1, For measuring the electrochemical workstation 2 of 3 impedance of fuel cell, circuit load 4 and for by 33 selective connection of anode flow field Electrochemical workstation 2 or the PCB unit 5 of circuit load 4, electrochemical workstation 2 include reference electrode 21, to electrode 22 and work Electrode 23, the anode of DC power supply 1 respectively with electrochemical workstation 2 to the cathode flow field 31 of electrode 22, fuel cell 3 and The end A of circuit load 4 connects, and the cathode of DC power supply 1 connects with the working electrode 23 of electrochemical workstation 2 and PCB unit 5 respectively Connect, one end of PCB unit 5 is connect with the anode flow field 33 of fuel cell 3, other end selectivity with electrochemical workstation 2 The connection of the end B of working electrode 23 or circuit load 4.The reference electrode 21 of electrochemical workstation 2 and test subregion 331 to be measured connect It connects.The end A of circuit load 4 is connect with the cathode flow field 31 of fuel cell 3.

The anode flow field 33 of fuel cell 3 is divided into 49 independent subregions, including 6 test subregions 331 and 43 Common subregion 332, wherein test 331 corresponding A 1 of subregion, A4, A7, G1, G4, G7, as shown in Figure 2.

PCB unit 5 includes multiple single-pole double-throw switch (SPDT)s 51, multiple regular taps 52 and multiple current sensors 53, hilted broadsword The a terminals of commutator 51 are connect with test subregion 331, b terminals and the electrochemical workstation 2 of single-pole double-throw switch (SPDT) 51 Working electrode 23 connects, and the c terminals of single-pole double-throw switch (SPDT) 51 are connect with circuit load 4, and in c terminals and circuit load 4 Connecting line on a current sensor 53 is set, common subregion 332 is connect with circuit load 4, and in common subregion 332 and circuit One current sensor 53 is set on the connecting line of load 4, and common subregion 332 passes through regular tap 52 and electrochemical workstation 2 Working electrode 23 connects.

It is when the electrochemical impedance time spectrum for measuring a certain test subregion 331, the corresponding hilted broadsword of the test subregion 331 to be measured is double The switch of throw switch 51, which is allocated to b terminals, connect test subregion 331 to be measured with the working electrode 23 of electrochemical workstation 2, The switch of the remaining test corresponding single-pole double-throw switch (SPDT) 51 of subregion 331 is allocated to c terminals, and regular tap 52 disconnects.

When the whole electrochemical impedance time spectrum of measurement fuel cell 3, the corresponding single-pole double-throw switch (SPDT) 51 of all test subregions 331 Switch be allocated to c terminals, when regular tap 52 is connected, not can be carried out EIS experiment under this state.Current density distribution such as Fig. 3 Shown: maximum region B2 is 679mAcm^-2；Minimum Area is D1, is 679mAcm^-2。

The corresponding single-pole double-throw switch (SPDT) 51 in the region G4 is allocated to b terminals, disconnects regular tap 52, each area's current density point Cloth is as shown in figure 4, highest current density region is B2, for 677mAcm^-2；Minimum Area is D1, is 301mAcm^-2, and it is first Test (Fig. 3) difference that begins is little, it is seen that logical DC, which is reduced, surveys the influence that part EIS is generated, and effectively improves Local electrochemical resistance Anti- spectrum testing system.

Comparative example

Using the connection type similar with Fig. 1, the difference is that cancel DC power supply 1, using identical test condition, The corresponding single-pole double-throw switch (SPDT) 51 in the region G4 is allocated to b terminals, disconnects regular tap 52.Each area's current density distribution is as schemed Shown in 5, the region of highest current density is G3, is 743mAcm^-2；Minimum Area is G4, is worth for 0mAcm^-2.Current density Minimum and maximum region has changed, and numerical value change is larger, illustrates that operating condition changes greatly, if directly tested, knot Former operating condition of the fruit just with expectation test is not inconsistent.

This is because the region and current sensor disconnect, from schematic diagram it can be seen that EIS when G4 subregion carries out EIS test When test, which can disconnect with load, only connect with electrochemical workstation.Because that DC DC power supply is not added, it can be seen that No electric current at this, the subregion are equivalent to open circuit.

Claims

1. A device for improving the measurement accuracy of electrochemical impedance spectroscopy of a fuel cell subregion, the fuel cell (3) to be measured comprises a cathode flow field (31), a membrane electrode (31) and an anode flow field (33) stacked in sequence ), characterized in that the device comprises a DC power supply (1), an electrochemical workstation (2) for measuring the impedance of a fuel cell (3), a circuit load (4) and a selective connection for the anode flow field (33) an electrochemical workstation (2) or a PCB unit (5) of a circuit load (4), the electrochemical workstation (2) comprising a reference electrode (21), a counter electrode (22) and a working electrode (23), the direct current The positive electrode of the power source (1) is respectively connected to the counter electrode (22) of the electrochemical workstation (2), the cathode flow field (31) of the fuel cell (3) and the A terminal of the circuit load (4). ) of the negative electrode is respectively connected with the working electrode (23) of the electrochemical workstation (2) and the PCB unit (5), one end of the PCB unit (5) is connected with the anode flow field (33) of the fuel cell (3), and the other One end is selectively connected with the working electrode (23) of the electrochemical workstation (2) or the B end of the circuit load (4);

The anode flow field (33) of the fuel cell (3) is equally divided into a plurality of independent test zones (331) and a plurality of common zones (332).

2. A device for improving the measurement accuracy of fuel cell partition electrochemical impedance spectroscopy according to claim 1, wherein the PCB unit comprises a plurality of SPDT switches (51), a plurality of common switches ( 52) and a plurality of current sensors (53), the terminal a of the SPDT switch (51) is connected to the test partition (331), and the terminal b of the SPDT switch (51) is connected to the electrochemical workstation (2) The working electrode (23) of the single-pole double-throw switch (51) is connected to the circuit load (4), and a current sensor (53) is arranged on the connection line between the c-terminal and the circuit load (4). ), the common partition (332) is connected with the circuit load (4), and a current sensor (53) is set on the connection line between the common partition (332) and the circuit load (4), and the common partition (332) passes through The common switch (52) is connected with the working electrode (23) of the electrochemical workstation (2).

3. A device for improving the measurement accuracy of a fuel cell subregion electrochemical impedance spectroscopy according to claim 2, wherein when measuring the electrochemical impedance spectroscopy of a certain test subregion (331), the test to be tested The switch of the SPDT switch (51) corresponding to the subarea (331) is turned to the b terminal so that the test subarea (331) to be tested is connected with the working electrode of the electrochemical workstation (2). The switch of the throw switch (51) is turned to the c terminal, and the common switch (52) is disconnected;

When measuring the overall electrochemical impedance spectrum of the fuel cell, the switches of the SPDT switches (51) corresponding to all the test zones (331) are turned to the c terminal, and the common switch (52) is turned on.

4. a kind of device that improves the measurement accuracy of fuel cell subregion electrochemical impedance spectroscopy according to claim 3, is characterized in that, the reference electrode (21) of described electrochemical workstation (2) and the test subregion ( 331) Connect.

5. A device for improving the measurement accuracy of a fuel cell partitioned electrochemical impedance spectrum according to claim 1, wherein the A terminal of the circuit load (4) and the cathode flow field of the fuel cell (3) (3) 31) Connect.

6. A method for improving the measurement accuracy of the electrochemical impedance spectroscopy of a fuel cell partition by using the device according to any one of claims 1 to 5, characterized in that, comprising the following steps:

(1) First, without incorporating the DC power supply (1) into the circuit, connect all the test sub-zones (331) and common sub-zones (332) to the circuit load (4), and then test the sub-zone current on each test sub-zone (331) value, and record it for use in subsequent steps;

(2) Connect the DC power supply (1) to the circuit forming device, connect a certain test subsection (331) to the DC power supply (1), and then make other test subsections (331) and common subsections (332) selectively pass through the PCB unit The ground is connected to the B end of the circuit load (4), and the input current value of the DC power supply (1) is the subregional current value of the test subregion (331) measured in the step (1), through the electrochemical workstation (2). ) record the impedance value of the test partition (331);

(3) Repeat step (2), switch each test sub-region (331) to be connected to the DC power supply (1) in turn, and record the impedance values of all test sub-regions (331) through the electrochemical workstation (2), that is, obtain the sub-region electrochemical AC Impedance spectrum.