CN109860656B - Direct methanol fuel cell with uniform fuel supply and working method thereof - Google Patents

Abstract

A direct methanol fuel cell with uniform fuel supply and a working method thereof, comprising a methanol fuel cell body, a methanol buffer zone, a perforated plate, and a methanol evaporation zone arranged on the anode side of the methanol fuel cell body, and the methanol storage tank and the methanol supply pump are used to supply the methanol to the methanol fuel cell body. The methanol evaporation zone can stably transport liquid-phase methanol. The invention applies the tapered and gradually expanded structure to the methanol evaporation area, which makes the methanol evaporation process more energy-efficient and efficient; the output of methanol vapor is accurately and efficiently controlled by controlling the external heating circuit and the methanol supply pump, so that the methanol fuel cell can be accurately and stably controlled. output power. The present invention uses methanol vapor as fuel, which can greatly reduce methanol penetration, increase fuel energy density, further improve cell efficiency, accurately produce methanol vapor, and accurately control the output stable voltage of the fuel cell. To reduce energy consumption to a certain extent, the battery as a whole has the characteristics of precision, stability and high efficiency.

Description

A kind of fuel uniform supply direct methanol fuel cell and its working method

technical field

The invention relates to the field of fuel cells, in particular to a direct methanol fuel cell with uniform fuel supply and a working method thereof.

Background technique

Direct methanol fuel cell (DMFC) is considered to be one of the most promising mobile power sources for electronic products due to its simple structure, normal temperature operation, high system volume specific energy, and convenient fuel storage and transportation. It has a wide range of application prospects in the fields of transportation, national defense and so on, so it has become a research hotspot of many scholars at home and abroad.

The electrode and cell reactions of the direct methanol fuel cell are as follows:

The anode reaction is CH ₃ OH+H ₂ 0→6H ⁺ +6e ^- +CO ₂

The cathodic reaction is 3/2O ₂ +6H ⁺ +6e ^- →3H ₂ O

The overall reaction of the battery is CH ₃ OH+3/2O ₂ →2H ₂ O+CO ₂

At present, the research of direct methanol fuel cell mostly focuses on the field of using liquid methanol as fuel, but because the fuel supply of methanol fuel cell mostly needs to be mixed with water, which reduces the energy density of the fuel, and at the same time, there is serious methanol in the operation process. The penetration problem, while causing a lot of waste of raw materials, reduces the energy utilization rate and seriously weakens the performance of the battery, which brings great difficulties to the improvement of the performance of the methanol fuel cell.

Studies have shown that the participation of methanol in the fuel cell reaction in the form of vapor can reduce the penetration of methanol and further improve the utilization efficiency of methanol. During the process, the methanol flow cannot be accurately controlled, which further affects the stable operation of the fuel cell. Therefore, in view of the above-mentioned problems of low efficiency, difficult distribution, and easy leakage of methanol fuel cells, a methanol fuel cell with high working efficiency and strong control precision is urgently needed.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a direct methanol fuel cell with precise, high efficiency, stable operation and continuous output of fuel uniform supply and its working method.

In order to achieve the above purpose, the fuel uniformly supplied direct methanol fuel cell of the present invention comprises a methanol fuel cell body and a cathode flow field, a cathode diffusion layer, a cathode catalytic layer, a diaphragm, an anode catalytic layer, and an anode diffusion layer arranged in the methanol fuel cell body. and the anode flow field; wherein the diaphragm is connected with the cathode catalytic layer and the anode catalytic layer, the cathode diffusion layer is connected with the cathode flow field and the cathode catalytic layer, and the anode diffusion layer is connected with the anode catalytic layer and the anode flow field;

A methanol evaporation zone with an external circuit is installed on the anode side of the methanol fuel cell body, and an electric heating plate made of an electric heating material with several methanol flow channels in a tapered and gradually expanded structure is installed on the outlet side of the methanol evaporation zone. The outlet side of the evaporation zone is provided with a porous plate, the other side of the perforated plate is connected to the methanol buffer zone, and the other side of the methanol buffer zone is connected to the anode flow field; the inlet of the methanol evaporation zone is connected to the methanol storage tank through a methanol supply pump.

The cathode flow field is a conductive metal material or carbon material, wherein a flow channel is processed inside the cathode flow field, and the flow channel is a serpentine flow channel, a parallel flow channel, a discontinuous flow channel or a flow channel in an active methanol fuel cell. The interdigitated flow channel is a point flow channel, a serpentine flow channel, a parallel flow channel, a discontinuous flow channel or an interdigitated flow channel in the case of a passive methanol fuel cell.

The cathode diffusion layer is a conductive metal material or carbon material with a porous structure; the cathode catalytic layer is a catalyst with catalytic reduction performance.

The membrane is a proton exchange membrane with proton conduction capability.

The anode catalytic layer is a catalyst with catalytic oxidation performance.

The anode diffusion layer is a metal material or a carbon material with a porous structure.

The anode flow field is made of metal material or carbon material, and the inside of the anode flow field is processed into a serpentine flow channel, a parallel flow channel, a discontinuous flow channel or an interdigitated flow channel.

The porous plate is a porous structure plate of metal material, carbon material or organic material.

The methanol supply pump is a positive displacement pump, an impeller pump or a jet pump; the methanol storage tank is made of polyethylene or polyoxymethylene which is a methanol-resistant material.

The working method for evenly supplying fuel to a direct methanol fuel cell includes the following steps:

Step S100: Preparation and supply of methanol vapor: the methanol evaporation area is powered on to heat the electric heating plate made of the internal electric heating material, and the temperature of the internal structure wall surface of the methanol evaporation area is further controlled by controlling the current size; the methanol supply pump makes methanol flow into methanol In the evaporation area, the methanol flow is controlled by the methanol supply pump; after the methanol flows into the methanol evaporation area, it passes through the tapered structure of the methanol flow channel of the tapered and gradually expanded structure and the inner wall of the methanol flow channel of the electric heating plate in the methanol evaporation area undergoes compression and heat exchange. The gradual expansion structure makes the methanol vapor mix evenly; further, the methanol vapor flows into the methanol buffer zone from the methanol evaporation area through the porous plate to make the mixing more uniform;

Step S200: reaction and discharge of methanol vapor: methanol vapor is evenly distributed through the anode flow field, and further flows into the anode catalytic layer through the anode diffusion layer to undergo oxidation reaction with water from the cathode side to generate carbon dioxide, electrons and protons, and the carbon dioxide is respectively catalyzed by the anode layer, anode diffusion layer, anode flow field and methanol buffer are discharged to the atmosphere, electrons are introduced into the external circuit through the anode catalytic layer, anode diffusion layer and anode flow field respectively, and protons migrate through the diaphragm to the cathode catalytic layer under the action of the electric field; , the electrons enter the cathode catalytic layer through the cathode flow field and cathode diffusion layer respectively through the external circuit, oxygen is pumped by an air pump or oxygen bottle and enters the cathode catalytic layer through the cathode flow field and cathode diffusion layer, and the protons from the anode side are catalyzed at the cathode The layer undergoes a reduction reaction with oxygen and protons to generate water; the above process completes the discharge of the methanol fuel cell.

In the present invention, the methanol flow channel with the gradually narrowing and expanding structure is applied to the methanol evaporation area, which can improve the methanol gasification efficiency and mixing degree to a greater extent. A constant flow of methanol vapor participates in the cell reaction, thereby improving the working efficiency and stability of the methanol fuel cell.

Compared with the prior art, the present invention has the following advantages and effects:

(1) The present invention adopts the self-heating and self-circulation method to provide gas-phase fuel for the battery, effectively reduces the penetration of methanol, improves the output performance of the battery, and then improves the fuel utilization rate of the battery;

(2) Compared with the traditional permeation gasification technology to provide methanol vapor for the cell, the methanol heated gasification technology can achieve the effect of accurately controlling the methanol vapor flow by controlling the methanol supply pump and external power supply to ensure the stable output of the methanol fuel cell;

(3) In the present invention, the methanol evaporation zone adopts a tapered and gradually expanded structure, which can reduce the power consumption of the heating process to a greater extent and make the methanol vapor fully mix, so that the methanol vapor can be stably and uniformly provided for the battery, and the space and time can be realized. accurate and uniform feeding.

Description of drawings

FIG. 1 is a schematic diagram of the overall structure of the present invention.

In the figure, 1- cathode flow field, 2- cathode diffusion layer, 3- cathode catalytic layer, 4- diaphragm, 5- anode catalytic layer, 6- anode diffusion layer, 7- anode flow field, 8- methanol buffer, 9 - Multi-hole plate, 10- methanol evaporation area, 11- methanol supply pump, 12- methanol storage tank, 13- electric heating plate.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings.

1, the present invention includes a cathode flow field 1, a cathode diffusion layer 2, a cathode catalytic layer 3, a diaphragm 4, an anode catalytic layer 5, an anode diffusion layer 6 and an anode flow field 7 arranged on the methanol fuel cell body; wherein the diaphragm 4 is connected with the cathode catalytic layer 3 and the anode catalytic layer 5, the cathode diffusion layer 2 is connected with the cathode flow field 1 and the cathode catalytic layer 3, and the anode diffusion layer 6 is connected with the anode catalytic layer 5 and the anode flow field 7;

The cathode flow field 1 should be made of conductive materials such as metal materials and carbon materials, and a flow channel is processed inside the cathode flow field 1. The flow channel includes a serpentine flow channel, a parallel flow channel, and a discontinuous flow channel in an active methanol fuel cell. In the case of passive methanol fuel cells, it includes point-like flow channels, serpentine flow channels, parallel flow channels, discontinuous flow channels, interdigitated flow channels, etc.; the cathode diffusion layer 2 should be porous The cathode catalytic layer 3 includes a catalyst with catalytic reduction performance; the diaphragm 4 should be a proton exchange membrane with proton conduction capability; the anode catalytic layer 5 includes a catalyst with catalytic oxidation performance; the anode The diffusion layer 6 should be a conductive material such as a metal material with a porous structure or a carbon material; the anode flow field 7 should be a conductive material such as a metal material, carbon material, etc., and a flow channel is processed inside the anode flow field 7, and the flow channel includes a serpentine flow. channel, parallel flow channel, discontinuous flow channel, interdigitated flow channel, etc.

A methanol evaporation zone 10 with an external circuit is also installed on the anode side of the methanol fuel cell body, wherein a plurality of electric heaters made of electrothermal materials with methanol flow channels with a tapered and expanded structure are installed on the outlet side of the methanol evaporation zone 10 The plate 13 is provided with a porous plate 9 made of metal material, carbon material or organic material on the outlet side of the methanol evaporation zone 10. The other side of the porous plate 9 is connected to the methanol buffer 8, and the other side of the methanol buffer 8 is connected to the anode flow. Field 7 is connected; methanol supply pump 11 is also provided on the inlet side of methanol evaporation area 10 , and the inlet of methanol supply pump 11 is connected with methanol storage tank 12 .

The methanol buffer 8 is provided with a carbon dioxide discharge hole; the methanol supply pump 11 is a positive displacement pump, an impeller pump or a jet pump; the methanol storage tank 12 is made of methanol-resistant materials, wherein the methanol-resistant materials include polyethylene or polyoxymethylene, etc. .

The working method of the direct methanol fuel cell of the present invention comprises the following steps:

Step S100: Preparation and supply of methanol vapor: the methanol evaporation area 10 is powered on to heat the electric heating plate 13 made of the electric heating material inside, and the temperature of the internal structure wall surface of the methanol evaporation area 10 is further controlled by controlling the magnitude of the current; the methanol supply pump 11 Methanol flows into the methanol evaporation zone 10, and the methanol flow is controlled by the air methanol supply pump 11; after the methanol flows into the methanol evaporation zone 10, the process is carried out through the tapered structure of the methanol flow channel of the tapered and gradually expanded structure and the inner wall surface of the methanol flow channel of the electric heating plate in the methanol evaporation zone 10. Compression heat exchange is evaporated into methanol vapor, and the methanol vapor is further mixed evenly through the gradual expansion structure; further, the methanol vapor flows from the methanol evaporation zone 10 through the porous plate 9 into the methanol buffer zone 8 to make the mixing more uniform;

Step S200: reaction and discharge of methanol vapor: methanol vapor is evenly distributed through the anode flow field 7, and further flows into the anode catalytic layer 5 through the anode diffusion layer 6 to undergo an oxidation reaction with water from the cathode side to generate carbon dioxide, electrons and protons. It is discharged to the atmosphere through the anode catalytic layer 5, anode diffusion layer 6, anode flow field 7 and methanol buffer 8, and electrons are introduced into the external circuit through the anode catalytic layer 5, anode diffusion layer 6 and anode flow field 7 respectively, and the protons are under the action of the electric field. It migrates to the cathode catalytic layer 3 through the diaphragm 4; at the same time, the electrons enter the cathode catalytic layer 3 through the cathode flow field 1 and the cathode diffusion layer 2 respectively through the external circuit, and the oxygen is pumped by an air pump or an oxygen bottle and passes through the cathode flow field 1, The cathode diffusion layer 2 enters the cathode catalytic layer 3, and the protons from the anode side undergo a reduction reaction with oxygen and protons in the cathode catalytic layer 3 to generate water; the above process completes the discharge of the methanol fuel cell.

The invention adopts the methanol heated gasification technology (methanol evaporation zone) to provide gas-phase fuel for the battery, effectively reduces the penetration of methanol, improves the output performance of the battery, and further improves the fuel utilization rate of the battery; The battery provides methanol vapor, and the methanol heated gasification technology can accurately control the methanol vapor flow through the control of the methanol supply pump and external power supply to ensure the stable output of the methanol fuel cell. The power consumption of the heating process is greatly reduced and the methanol vapor is fully mixed, so that the methanol vapor can be supplied to the battery stably and uniformly, and the accurate and uniform feeding in space and time can be realized.

Claims (10)

1. A direct methanol fuel cell with uniform fuel supply, characterized in that it comprises a methanol fuel cell body and a cathode flow field (1), a cathode diffusion layer (2), and a cathode catalytic layer (3) arranged in the methanol fuel cell body. , diaphragm (4), anode catalytic layer (5), anode diffusion layer (6) and anode flow field (7); wherein diaphragm (4) is connected with cathode catalytic layer (3), anode catalytic layer (5), and cathode diffusion The layer (2) is connected with the cathode flow field (1) and the cathode catalytic layer (3), and the anode diffusion layer (6) is connected with the anode catalytic layer (5) and the anode flow field (7); A methanol evaporation zone (10) with an external circuit is installed on the anode side of the methanol fuel cell body, and the outlet side of the methanol evaporation zone (10) is installed with an electrothermal material with several tapered and gradually expanded methanol flow channels. The electric heating plate (13) is provided with a perforated plate (9) on the outlet side of the methanol evaporation zone (10), and the other side of the perforated plate (9) is connected with a methanol buffer zone (8) provided with a carbon dioxide discharge hole. The other side of (8) is connected to the anode flow field (7); the inlet of the methanol evaporation zone (10) is connected to the methanol storage tank (12) through a methanol supply pump (11). 2. The direct methanol fuel cell according to claim 1, characterized in that the cathode flow field (1) is a conductive metal material or carbon material, wherein the inside of the cathode flow field (1) is processed with a flow channel , in which the flow channel is a serpentine flow channel, a parallel flow channel, a discontinuous flow channel or an interdigitated flow channel in an active methanol fuel cell, and a point-shaped flow channel, a serpentine flow channel, Parallel runners, discontinuous runners or interdigitated runners. 3. The direct methanol fuel cell according to claim 1, wherein the cathode diffusion layer (2) is a conductive metal material or carbon material with a porous structure; the cathode catalytic layer (3) is a A catalyst with catalytic reduction properties. 4 . The direct methanol fuel cell according to claim 1 , wherein the membrane ( 4 ) is a proton exchange membrane with proton conduction capability. 5 . 5 . The direct methanol fuel cell according to claim 1 , wherein the anode catalytic layer ( 5 ) is a catalyst with catalytic oxidation performance. 6 . 6 . The direct methanol fuel cell according to claim 1 , wherein the anode diffusion layer ( 6 ) is a metal material or a carbon material with a porous structure. 7 . 7. The direct methanol fuel cell according to claim 1, wherein the anode flow field (7) is made of metal material or carbon material, and the inside of the anode flow field (7) is processed with a serpentine flow channel , parallel flow channels, discontinuous flow channels or interdigitated flow channels. 8 . The direct methanol fuel cell according to claim 1 , wherein the porous plate ( 9 ) is a porous structure plate of metal material, carbon material or organic material. 9 . 9. The fuel uniformly supplied direct methanol fuel cell according to claim 1, wherein the methanol supply pump (11) adopts a positive displacement pump, an impeller pump or a jet pump; the methanol storage tank (12) adopts a durable Methanol material made of polyethylene or polyoxymethylene. 10. A working method for uniformly supplying fuel to a direct methanol fuel cell as claimed in claim 1, characterized in that it comprises the following steps: Step S100: Preparation and supply of methanol vapor: the methanol evaporation area is powered on to heat the electric heating plate made of the internal electric heating material, and the temperature of the internal structure wall surface of the methanol evaporation area is further controlled by controlling the current size; the methanol supply pump makes methanol flow into methanol In the evaporation area, the methanol flow is controlled by the methanol supply pump; after the methanol flows into the methanol evaporation area, it passes through the tapered structure of the methanol flow channel of the tapered and gradually expanded structure and the inner wall of the methanol flow channel of the electric heating plate in the methanol evaporation area undergoes compression and heat exchange. The gradual expansion structure makes the methanol vapor mix evenly; further, the methanol vapor flows into the methanol buffer zone from the methanol evaporation area through the porous plate to make the mixing more uniform; Step S200: reaction and discharge of methanol vapor: methanol vapor is evenly distributed through the anode flow field, and further flows into the anode catalytic layer through the anode diffusion layer to undergo oxidation reaction with water from the cathode side to generate carbon dioxide, electrons and protons, and the carbon dioxide is respectively catalyzed by the anode Layer, anode diffusion layer, anode flow field and methanol buffer are discharged to the atmosphere from the carbon dioxide discharge hole, electrons are introduced into the external circuit through the anode catalytic layer, anode diffusion layer and anode flow field respectively, and protons migrate through the diaphragm to the cathode under the action of the electric field At the same time, electrons enter the cathode catalytic layer through the cathode flow field and cathode diffusion layer respectively through the external circuit, and oxygen is pumped by an air pump or oxygen bottle and enters the cathode catalytic layer through the cathode flow field and cathode diffusion layer. The protons undergo a reduction reaction with oxygen and protons in the cathode catalytic layer to generate water; the above process completes the discharge of the methanol fuel cell.

Images