An alcohol fuel cell stack and a concentration detection method thereof

Abstract

The present invention provides an alcohol fuel cell stack, including a power generation module and a concentration sensing module, and also including a front end plate and a rear end plate, the front end plate is provided with a fuel inlet and a reactant outlet; the power generation module is formed by stacking power generation monomers composed of a plate and a membrane electrode, and the front and rear ends of the power generation module are provided with conductive collectors; the concentration sensing module is sequentially stacked by a first insulating plate, a concentration sensing anode plate, a concentration sensing membrane electrode, a concentration sensing cathode plate and a second insulating plate, and a concentration sensing temperature sensing hole is provided on the first or second insulating plate near the plate. The present invention also provides a method for detecting the concentration of alcohol fuel passing through the stack, the calibration of the concentration sensing module and the determination of the concentration of the fuel at the inlet or outlet of the stack by measuring the temperature. The present invention has improved reliability, improved integration, easy processing and improved precision.

Description

Technical Field

[0001] The invention relates to a fuel cell, and in particular to an alcohol fuel cell stack and a concentration detection method thereof. Background Art

[0002] At present, most sensors suitable for alcohol monitoring adopt the fuel cell type. This sensor is similar to a fuel cell unit. Because its structure is very similar to DAFC, it has considerable advantages in industrialization. Among them, the driving mode sensor working at a constant voltage has the advantages of strong response signal, wide concentration range, and long life. Its working principle is: a constant potential that can cause methanol to undergo electrochemical oxidation is applied to the anode of the membrane electrode assembly (MEA). The methanol solution can directly reach the anode catalyst layer from the anode feed, or it can be fed from the cathode and reach the anode through the proton exchange membrane. In either case, it must pass through an appropriate barrier layer to reach the electrode surface carrying precious metal catalysts such as Pt for electrochemical oxidation. Due to the effect of the barrier layer, a limiting diffusion current is generated, and the methanol concentration can be determined by measuring the limiting diffusion current.

[0003] Existing alcohol fuel cells usually use a concentration sensor in the flow path to measure concentration. Most sensors are fuel cell type. Such concentration sensors are easily affected by dry and wet states, adsorbed ions, etc., resulting in low stability and reliability. In addition, such concentration sensors are affected by the size of the proton exchange membrane, and the response current is too small. If the signal is amplified, the accuracy will be affected. In addition, the sensor structure set in the flow path is prone to leakage. Existing alcohol fuel cells have poor reliability, poor accuracy, and are prone to liquid leakage.

[0004] Therefore, it is necessary to improve the existing technology. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an efficient alcohol fuel cell stack and a concentration detection method thereof.

[0006] In order to solve the above technical problems, the present invention provides an alcohol fuel cell stack, including a power generation module and a concentration sensing module, and also including a front end plate and a rear end plate, wherein the front end plate is provided with a fuel inlet and a reactant outlet; the power generation module is formed by stacking power generation units consisting of pole plates and membrane electrodes, and conductive collectors are provided at the front and rear ends of the power generation module; the concentration sensing module is formed by stacking a first insulating plate, a concentration sensing anode plate, a concentration sensing membrane electrode, a concentration sensing cathode plate and a second insulating plate in sequence, wherein a concentration sensing temperature sensing hole is provided on the first or second insulating plate near the pole plate, and concentration sensing conductive interfaces are respectively provided on the first and second insulating plates near the pole plate sides.

[0007] As an improvement to an alcohol fuel cell stack of the present invention: the concentration sensing anode plate and the concentration sensing cathode plate are provided with sealing line grooves.

[0008] As an improvement to an alcohol fuel cell stack of the present invention: the concentration response of the concentration sensing module obtains an accurate value through temperature compensation.

[0009] As an improvement to an alcohol fuel cell stack of the present invention, the concentration sensing conductive interface is kept constant within a voltage range of 0.6-0.9V.

[0010] As an improvement to an alcohol fuel cell stack of the present invention: the concentration sensor module is arranged near the front end plate, or near the rear end plate.

[0011] The present invention also provides a method for detecting the concentration of alcohol fuel passing through the stack, comprising the following steps: calibration of the concentration sensor module and determining the concentration of the fuel at the inlet or outlet of the stack by measuring the temperature. The specific steps are as follows:

[0012] S1: applying a preset voltage to the concentration sensing module, the concentration sensing conductive interface close to the concentration sensing anode plate is the anode interface, and close to the concentration sensing cathode plate is the cathode interface, the voltage between the anode interface and the cathode interface is constant at a value within the range of 0.6-0.9V, the anode interface is at a high potential relative to the cathode interface, and an alcohol fuel solution of a set concentration is introduced into the battery stack, the solution is heated, the current at both ends of the concentration sensing module and the temperature of the concentration sensing module are measured, and a relationship between current and temperature is generated, and the relationship between the current, concentration and temperature is fitted as I=f(C,T), wherein I-output current (A), C-set solution concentration (mol / L), and T-sensing module temperature (℃);

[0013] S2: Apply a preset voltage to the concentration sensor module, which is a constant voltage of 0.6 to 0.9 V. Pass the alcohol fuel solution to be tested into a normally functioning fuel cell stack, measure the current at both ends of the concentration sensor module and the temperature of the concentration sensor module, and then the corresponding solution concentration can be determined by the relationship I=f(C,T) obtained in S1.

[0014] As an improvement to the method for detecting the concentration of alcohol fuel passing through a fuel cell stack of the present invention: the set concentration of the alcohol fuel passing through the fuel cell stack in step S1 is 0.3-1.2 mol / L.

[0015] As an improvement to the method for detecting the concentration of alcohol fuel passing through a fuel cell stack of the present invention, the method includes the following steps: calibration of the concentration sensing module and determining the concentration of the fuel at the inlet or outlet of the fuel cell stack by measuring the temperature. The specific steps are as follows:

[0016] A1: A preset voltage is applied to the concentration sensing module. The concentration sensing conductive interface close to the concentration sensing anode plate is the anode interface, and the interface close to the concentration sensing cathode plate is the cathode interface. The voltage between the anode interface and the cathode interface is constant at a value within the range of 0.6-0.9V, and the cathode interface is at a high potential relative to the anode interface. An alcohol fuel solution of a set concentration is introduced into the battery stack, and the solution is heated to increase the temperature. The current at both ends of the concentration sensing module and the temperature of the concentration sensing module are measured, and the relationship between the current and the temperature is generated. The relationship between the current, the concentration and the temperature is fitted as I=g(C,T), where I-output current (A), C-set solution concentration (mol / L), and T-sensing module temperature (℃);

[0017] A2: Apply a preset voltage to the concentration sensor module, which is a constant voltage of 0.6 to 0.9 V. Pass the alcohol fuel solution to be tested into a normally functioning fuel cell stack, measure the current at both ends of the concentration sensor module and the temperature of the concentration sensor module, and then the corresponding solution concentration can be determined by the relationship I=g(C,T) obtained in A1.

[0018] The technical advantages of the alcohol fuel cell stack and the concentration detection method thereof of the present invention are:

[0019] The present invention provides an alcohol fuel cell stack, which integrates the function of concentration sensing, improves the reliability and measurement accuracy of concentration sensing, and simplifies the system structure.

[0020] The alcohol fuel cell stack and the concentration detection method thereof of the present invention are not affected by dry or wet states, adsorbed ions, etc., and have improved reliability, improved integration, easy processing, and improved precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0022] Figure 1 It is a structural schematic diagram of an alcohol fuel cell stack of the present invention;

[0023] Figure 2 yes Figure 1 A schematic diagram of the structure of the first insulating plate 201 and the front end plate 3;

[0024] Figure 3 yes Figure 1 A schematic structural diagram of the second insulating plate 205;

[0025] Figure 4 is the temperature-current curve when the methanol solution obtained in Example 1 is 0.5 mol / L;

[0026] Figure 5 is the solution temperature-current curve obtained in Example 1 when the anode flow rate is 4 ml / min;

[0027] Figure 6 This is the solution temperature-current curve obtained in Example 2 when the anode flow rate is 4 ml / min. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0029] Embodiment 1: An alcohol fuel cell stack, such as Figure 1-4 As shown, it includes a power generation module 1 and a concentration sensor module 2, and also includes a front end plate 3 and a rear end plate 4, and the front end plate 3 is provided with a fuel inlet 301 and a reactant outlet 302;

[0030] The fuel inlet 301 is used to introduce an alcohol fuel solution, and the concentration of the alcohol fuel solution is 0.3-1.2 mol / L.

[0031] The power generation module 1 is formed by stacking power generation units consisting of polar plates and power generation module membrane electrodes 102. The polar plates are bipolar plates 103. The bipolar plates 103 include power generation module anode plates 104 and power generation module cathode plates 101. Several power generation module anode plates 104 and power generation module cathode plates 101 are stacked alternately in sequence, and power generation module membrane electrodes 102 are arranged between adjacent power generation module anode plates 104 and power generation module cathode plates 101.

[0032] The front and rear ends of the power generation module 1 are provided with conductive collecting ears 110; the conductive collecting ears 110 include a positive collecting ear 111 of the power generation module and a negative collecting ear 112 of the power generation module;

[0033] The concentration sensing module 2 is stacked in sequence by a first insulating plate 201, a concentration sensing anode plate 202, a concentration sensing membrane electrode 203, a concentration sensing cathode plate 204 and a second insulating plate 205. The concentration sensing plates (concentration sensing anode plate 202 and concentration sensing cathode plate 204) on the first insulating plate 201 or the second insulating plate 205 are provided with concentration sensing temperature sensing holes 206. The first insulating plate 201 and the second insulating plate 205 are provided with concentration sensing conductive interfaces 207 on one side close to the concentration sensing plates (concentration sensing anode plate 202 and concentration sensing cathode plate 204). The first insulating plate 201 and the second insulating plate 205 are both provided with solution through holes 208 and fixing holes 209.

[0034] The concentration sensing conductive interface 207 includes a concentration sensing positive electrode interface and a concentration sensing negative electrode interface, and the concentration sensing positive electrode interface and the concentration sensing negative electrode interface are respectively arranged on the first insulating plate 201 and the second insulating plate 205 .

[0035] The concentration sensing anode plate 202 and the concentration sensing cathode plate 204 are provided with sealing line grooves;

[0036] The effective area of ​​the concentration sensing membrane electrode is 25-50cm 2 ;

[0037] The concentration response of the concentration sensing module 2 obtains an accurate value through temperature compensation.

[0038] The voltage between the two concentration sensing conductive interfaces 207 is kept constant within a range of 0.6-0.9V.

[0039] The concentration sensor module 2 is arranged near the front end plate 3 , or near the rear end plate 4 .

[0040] The method for detecting the concentration of alcohol fuel passing through the stack includes the following steps: calibration of the concentration sensor module 2 and determining the concentration of the fuel at the inlet or outlet of the stack by measuring the temperature. The specific steps are as follows:

[0041] S1: applying a preset voltage to the concentration sensing module, the concentration sensing conductive interface 207 close to the concentration sensing anode plate 202 is the anode interface, and close to the concentration sensing cathode plate 204 is the cathode interface, applying a preset voltage (the preset voltage is a value within the constant voltage range of 0.6 to 0.9V) through the concentration sensing conductive interface 207, the anode flow rate is a constant value (for example, 2ml / min, 4ml / min, 6ml / min), and the anode flow rate is measured by a liquid pump; the anode interface is at a high potential relative to the cathode interface;

[0042] An alcohol fuel solution of a set concentration is introduced into the fuel stack through the fuel inlet 301 on the front end plate 3 to heat the alcohol fuel solution;

[0043] The current at both ends of the concentration sensing module is measured through the concentration sensing conductive interface 207; the temperature of the concentration sensing module is measured through the concentration sensing temperature sensing hole 206; and the relationship between the current and the temperature is generated. The relationship between the current, the concentration and the temperature is fitted as I = f (C, T) = C * (K 1 *TK 2 );

[0044] Wherein, I is the output current (A) measured by the concentration sensing conductive interface 207, C is the set solution concentration (mol / L), T is the temperature of the sensing module (°C), K is 1 is the plate coefficient of one, K 2 is the plate coefficient of two,

[0045] like Figure 5 As shown, the experimental concentration sensing plate used in this embodiment 1 is used to fit the relationship between current, concentration and temperature to obtain K 1 is 0.15, K 2 is 0.092;

[0046] I=f(C,T)=C*(0.15*T-0.092);

[0047] The flow direction of the fuel is: the fuel enters from the fuel inlet 301, passes through the front end plate 3, the first insulating plate 201, the concentration sensor module 2, the second insulating plate 205, the power generation module 1 and the rear end plate 4 in sequence through the solution through hole 208, and then directly flows out of the reactant outlet 302 in the opposite direction through the solution through hole 208.

[0048] S2: Apply a preset voltage (consistent with the preset voltage in step S1) through the concentration sensing conductive interface 207, the preset voltage is a value within the constant voltage range of 0.6 to 0.9 V, pass the alcohol fuel solution to be tested into a normally functioning fuel cell, measure the current at both ends of the concentration sensing module 2 and the temperature of the concentration sensing module, and then the corresponding solution concentration can be determined by the relationship obtained in S1.

[0049] Example 2: An alcohol fuel cell stack, the structure of which is the same as that of Example 1, wherein the potentials of the cathode interface and the anode interface in the method for detecting the concentration of alcohol fuel passing through the stack are modified to "the cathode interface is at a high potential relative to the anode interface", and the rest is the same as that of Example 1.

[0050] Due to the reverse application of potential, the penetration rate is different, and the current response is different;

[0051] The relationship obtained in Example 2 is I=g(C,T)=C*(-0.273*T+6.56);

[0052] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. An alcohol fuel cell stack, comprising a power generation module and a concentration sensing module, and also comprising a front end plate and a rear end plate, wherein the front end plate is provided with a fuel inlet and a reactant outlet; the power generation module is formed by stacking power generation units consisting of polar plates and membrane electrodes, and the front and rear ends of the power generation module are provided with conductive collectors; the concentration sensing module is formed by stacking a first insulating plate, a concentration sensing anode plate, a concentration sensing membrane electrode, a concentration sensing cathode plate and a second insulating plate in sequence, wherein a concentration sensing temperature sensing hole is provided on the first insulating plate or the second insulating plate near the concentration sensing anode plate or the concentration sensing cathode plate, and a concentration sensing conductive interface is provided on one side of the first insulating plate and the second insulating plate near the concentration sensing anode plate and the concentration sensing cathode plate respectively; The concentration sensing anode plate and the concentration sensing cathode plate are both provided with sealing line grooves; The concentration sensor module is arranged near the front end plate; A method for detecting the concentration of alcohol fuel in an alcohol fuel cell stack, characterized in that: The method includes the following steps: calibration of the concentration sensor module and determination of the concentration of the fuel at the inlet of the fuel stack by measuring the temperature. The specific steps are as follows: S1: applying a preset voltage to the concentration sensing module, the concentration sensing conductive interface close to the concentration sensing anode plate is the anode interface, and close to the concentration sensing cathode plate is the cathode interface, the voltage between the anode interface and the cathode interface is a constant value in the range of 0.6-0.9V, the anode interface is at a high potential relative to the cathode interface, an alcohol fuel solution of a set concentration is introduced into the battery stack, the solution is heated, the current at both ends of the concentration sensing module is measured through the concentration sensing conductive interface, and the temperature of the concentration sensing module is measured through the concentration sensing temperature sensing hole, and a relationship between current and temperature is generated, and the relationship between the fitted current, concentration and temperature is I=f(C,T)=C*(0.15*T-0.092), wherein I is the output current measured by the concentration sensing conductive interface, in A, C is the set solution concentration, in mol / L, and T is the temperature of the sensor module, in °C; The flow direction of the fuel is: the fuel enters from the fuel inlet, passes through the front end plate, the concentration sensor module, the power generation module and the rear end plate in sequence through the solution through hole, and then directly flows out of the reactant outlet in the reverse direction through the solution through hole; S2: Apply a preset voltage to the concentration sensing module, which is a constant voltage of 0.6 to 0.9 V. Pass the alcohol fuel solution to be tested into a normally functioning fuel cell stack. Measure the current at both ends of the concentration sensing module through the concentration sensing conductive interface and measure the temperature of the concentration sensing module through the concentration sensing temperature sensing hole. The corresponding solution concentration can be determined by the relationship I=f(C,T)=C*(0.15*T-0.092) obtained in S1.

2. The alcohol fuel cell stack according to claim 1, characterized in that: The set concentration of the alcohol fuel solution in step S1 is 0.3-1.2 mol / L.

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