CN1808749A

CN1808749A - Fuel cell humidifier

Info

Publication number: CN1808749A
Application number: CNA2006100383038A
Authority: CN
Inventors: 乔永进; 沈建跃; 曲平; 康新
Original assignee: NANJING BONENG FUEL BATTERY CO Ltd
Current assignee: NANJING BONENG FUEL BATTERY CO Ltd
Priority date: 2006-02-15
Filing date: 2006-02-15
Publication date: 2006-07-26

Abstract

This invention discloses one fuel battery wet device, which comprises the following parts: isolation board, end board and wet unit, wherein, the isolation board two sides are located with one wet unit tightened by the outside end board; The total wet device is isolated into two wet areas through isolation board and the board has only the hole for second wet hot air flow and not for the reaction gas flow; two reaction gas are wetted in each area and the wet hot air passes isolation board from one side to other side to wet two reaction gas.

Description

Fuel cell humidifier

One, the technical field

The invention relates to a fuel cell, in particular toa fuel cell humidifier.

Second, background Art

A fuel cell stack is a device that generates electrical energy by an electrochemical reaction of hydrogen fuel and an oxidant. The core component of the device is a Membrane Electrode (MEA), which is composed of two porous gas diffusion layers and a proton exchange Membrane sandwiched therebetween. An electrochemical catalyst is attached to the interface of the proton exchange membrane and a gas diffusion layer (e.g., carbon paper).

Another important component of a fuel cell stack is the bipolar plate. The surface of the bipolar plate at least contains a gas guiding groove, the gas guiding groove provides a passage for gas participating in electrode reaction to reach the membrane electrode, and reaction products (such as water) generated in the reaction are discharged out of the electric pile through the gas guiding groove. The bipolar plate contains at least one cooling channel, through which a cooling medium (such as air or water) flows to carry away the heat generated in the reaction out of the stack. The bipolar plates are stamped, stamped or mechanically engraved from an electrically conductive material to provide channels for the flow of electrons. The bipolar plate has certain strength and provides support for the membrane electrode. The bipolar plate has certain air tightness, and the bipolar plate, the membrane electrode and the sealing material between the bipolar plate and the membrane electrode separate the fuel and the oxidant which take part in the reaction.

When hydrogen enters the hydrogen guiding grooves of the bipolar plate from the hydrogen inlet of the fuel cell stack, the hydrogen penetrates through the porous gas diffusion layer (such as carbon paper) to reach the surface of the catalyst. Under the action of the catalyst, hydrogen gas is electrochemically reacted, and hydrogen atoms lose electrons to become positive ions (protons). The electrons reach the electric appliance through the porous gas diffusion layer (such as carbon paper) and the bipolar plate, and then reach the catalyst surface on the other side of the membrane electrode through the bipolar plate and the porous gas diffusion layer (such as carbon paper). Under the action of the catalyst, the electrons electrochemically react with an oxidant (e.g., oxygen) that reaches the catalyst surface through a porous gas diffusion layer (e.g., carbon paper) and protons that reach the catalyst surface through a proton exchange membrane to generate a reaction product (e.g., water). The electrochemical reaction that occurs in a hydrogen fuel cell can be represented by the following reaction equation:

and (3) anode reaction:

and (3) cathode reaction:

the currently common proton exchange membrane is a perfluorosulfonic acid membrane containing C-F chainsAt the end of a C-F chain branch isA sulfonic acid group. Perfluorosulfonic acid membranes are selectively permeable membranes, through which only positive ions (e.g., protons) can pass, but not electrons and gases. In the fuel cell stack, after hydrogen is dissociated into protons and electrons at the anode by the catalyst, the protons are combined with water to form hydrated protons H⁺(nH₂O) from a sulfonic acid group (-SO) in a proton exchange membrane₃H) Transfer to another sulfonic acid group (-SO)₃H) And finally to the cathode side. If there is no water on the hydrogen side, hydrated protons cannot be formed, and the reaction cannot proceed. If the proton exchange membrane is in a dry state, hydrated protons are not in sulfonic acid groups (-SO)₃H) The reaction cannot proceed either. If the hydrogen is not humidified before entering the fuel cell stack, although water is generated during the reaction process, the humidity of the proton exchange membrane and the hydrogen in the gas inlet area of the membrane electrode is low, which may affect the performance and stability of the fuel cell stack. The lower humidity air can further degrade the proton transfer performance of the proton exchange membrane if the air is not humidified prior to entering the fuel cell stack. Humidification of air and hydrogen is necessary to ensure the power generation performance of the fuel cell stack.

At present, the proton exchange membrane fuel cell humidifier mainly adopts the following methods:

1. pure water bubbling method: the reaction gas is humidified while passing through purified water.

2. A water spraying method: the reactant gas is sprayed into misty water droplets before entering the stack.

3. And (3) a penetration method: on both sides of the membrane, through which water molecules can freely pass but gas cannot pass, purified water flows on one side, and reaction gas flows on the other side, and the reaction gas is humidified by water penetrating through the membrane.

Humidifiers using these several methods have common drawbacks:

1. requiring frequent addition of purified water to the humidifier increases the difficulty of maintaining the fuel cell system.

2. A heat source needs to be provided to the humidifier to secure the temperature and humidity of the reaction gas, which reduces the efficiency of the fuel cell and increases the cost of the fuel cell system.

The humidifier related to the Chinese patent application with the patent application number of CN02111824.8 and the name of 'a high-efficiency humidifying device for a fuel cell' is composed of a columnar inner container and a rotating motor, wherein the inner container is internally provided with a filler, and a diaphragm is arranged in the middle of the inner container. The moist hot air from the fuel cell passes through one side of the inner container, leaving entrained moisture in the filler. After the electrode is rotated 180 ℃, dry air passes through the side to carry away the water in the filler. The advantage of such a humidifier is that the water in the humidifier comes from the water generated in the fuel cell reaction and therefore does not need to be added additionally to the humidifier. However, such humidifiers have the following drawbacks:

1. the structure is complex, and the maintenance difficulty of the fuel cell system is increased.

2. The motor rotation consumes a portion of the energy, reducing the overall efficiency of the fuel cell.

3. The hydrogen cannot be humidified.

The humidifier of chinese patent application No. CN03115482.4, entitled "a high-efficiency humidifier suitable for low-voltage operation of fuel cell" uses hot and humid air exhausted from the fuel cell as a humidification source, and separates the hot and humid air from the reaction gas by a diaphragm. The membrane allows water molecules to pass freely but prevents gas from passing through. The moisture in the hot and humid air reaches one side of the reaction gas after penetrating through the membrane, and the reaction gas is humidified. The advantage of such a humidifier is that the water in the humidifier comes from the water generated in the fuel cell reaction and therefore does not need to be added additionally to the humidifier. However, the drawbacks of this humidifier are: it is not possible to humidify two reaction gases (e.g. hydrogen and air) simultaneously.

Third, the invention

1. The purpose of the invention is as follows: the object of the present invention is to overcome the above technical problems by providing a highly efficient and compact fuel cell humidifier which can humidify two reaction gases simultaneously.

2. The technical scheme is as follows: the invention relates to a fuel cell humidifier, which is characterized in that: the humidifying device comprises a partition board, end plates and humidifying units, wherein at least one humidifying unit is arranged on each side of the partition board and is clamped and fixed by the end plates on the outer sides, each humidifying unit comprises a guide plate and a humidifying membrane, wet and hot air guide grooves and a reaction gas guide groove are respectively arranged on two sides of each guide plate, a first wet and hot air through hole communicated with the wet and hot air guide grooves and a reaction gas through hole communicated with the reaction gas guide grooves are also arranged on each guide plate, and the humidifying membrane is clamped between one surface of one guide plate, which is provided with the wet and hot air guide grooves, and one surface of the other adjacent guide plate, which is provided with the reaction gas guide grooves, so that one humidifying unit is formed; the baffle plate is provided with a second damp and hot air through hole communicated with the first damp and hot air through hole, the end plates on the two sides are respectively provided with a damp and hot air inlet and a damp and hot air outlet communicated with the first damp and hot air through hole, the end plate on one side is also provided with a first reaction gas inlet and a first reaction gas outlet communicated with the reaction gas through hole, and the end plate on the other side is provided with a second reaction gas inlet and a second reaction gas outlet.

Divide into two humidifying districts with whole humidifier by the baffle, a humidifying district is arranged in the fuel (like hydrogen) of humidifying reaction gas, another humidifying district is arranged in the oxidant (like air) of humidifying reaction gas, only be used for the humid hot air through-hole of the second of humid hot air circulation on the baffle, and the air guide through-hole of no reaction gas circulation, so the reaction gas on its both sides only flows mutual noninterference in its respective humidifying district, and humid hot air then can flow into the humidifying district of opposite side from the humidifying district of one side through the humid hot air through-hole of second of baffle, can be with two kinds of reaction gas of humidifying simultaneously, not only make efficiency improve, the structure that also makes the humidifier simultaneously is compacter. The humidifier can utilize damp and hot air exhausted from a fuel cell as a humidifying source, the damp and hot air flows through the damp and hot air guide grooves on the guide plates through the inlet, reaction gas flows in the reaction gas guide grooves of the guide plates in respective humidifying areas, the humidifying films between the guide plates can allow water molecules to pass freely, but can prevent the gas from passing through, so that moisture in the damp and hot air penetrates through the humidifying films and then reaches one side of the reaction gas, and the reaction gas is humidified.

The two sides of the partition board are respectively provided with a damp and hot air diversion trench and a reaction gas diversion trench, wherein the damp and hot air diversion trench on one side is communicated with the second damp and hot air through hole, a groove is arranged on the side with the reaction gas diversion trench corresponding to the reaction gas through hole on the adjacent guide board, the groove is communicated with the reaction gas diversion trench on the partition board, and two sides of the partition board are respectively provided with a humidifying film to form two additional humidifying units corresponding to the adjacent guide board. The purpose of arranging the grooves is to enable reaction gas to smoothly flow in and flow out from the reaction gas through holes of the adjacent guide plates through the grooves, and meanwhile, the grooves are not communicated, so that the reaction gas only flows in the own humidification area and cannot pass through the partition plate to enter the other humidification area. The structure enables the baffle plate to also play the role of a guide plate, and further improves the efficacy of the humidifier.

The humidifying membrane can be a perfluorosulfonic acid membrane or other thin membranes which can pass water but can not pass gas.

3. Has the advantages that: the invention has the following advantages: (1) the whole humidifier is divided into two humidification areas by the partition board, two reaction gases are humidified in the respective humidification areas, and the damp hot air can flow into the humidification area on the other side from the humidification area on one side through the partition board, so that the two reaction gases can be humidified simultaneously; (2) the two sides of the clapboard can also be respectively provided with a damp and hot air diversion trench and a reaction gas diversion trench, and the two damp units are formed corresponding to the damp films and the diversion plates on the two sides. The baffle also acts as a deflector, further improving the efficacy of the humidifier.

Description of the drawings

FIG. 1 is an overall assembly view of the present invention;

FIG. 2 is a side of the baffle having hot humid air guide slots;

FIG. 3 is a side of the baffle having reactant gas flow channels;

FIG. 4 shows the side of the partition having hot and humid air guide grooves;

FIG. 5 is a view showing a side of a separator having a reaction gas guide groove;

FIG. 6 is a schematic structural view of embodiment 1 of the present invention;

FIG. 7 is a schematic flow diagram of two reaction gases in example 1;

FIG. 8 is a schematic structural view of embodiment 2 of the present invention;

FIG. 9 is a schematic flow diagram of two reaction gases in example 2;

fig. 10 is a schematic flow diagram of hot and humid air in two embodiments.

Fifth, detailed description of the invention

The invention is further illustrated by the following figures and examples:

as shown in figure 1, the invention discloses a fuel cell humidifier, which comprises a partition plate 1, an end plate 2 and humidification units, wherein at least one humidification unit is respectively arranged on two sides of the partition plate 1, and is clamped and fixed by an end plate 2 at the outer side, the humidifying unit comprises a guide plate 3 and a humidifying membrane 4, as shown in fig. 2 and 3, the guide plate 3 is provided with a humid hot air guide groove 5 and a reaction gas guide groove 6 on both sides, the guide plate 3 is further provided with a first humid hot air through hole 7 communicated with the humid hot air guide groove 5, the reaction gas through hole 8 is communicated with the reaction gas diversion trench 6, one surface of one diversionplate 3 provided with the hot and humid air diversion trench 5 and one surface of the other adjacent diversion plate 3 provided with the reaction gas diversion trench 6 are clamped with the humidifying film 4 to form a humidifying unit, and the two adjacent diversion plates 3 and the humidifying film 4 are kept sealed by the sealing ring 16 so that the reaction gas and the hot and humid air do not leak; the partition board 1 is provided with a second moist hot air through hole 9 communicated with the first moist hot air through hole 7, as shown in fig. 4 and 5, both sides of the partition board 1 are also respectively provided with a moist hot air guiding groove 5 and a reaction gas guiding groove 6, and the moist hot air guiding groove 5 is communicated with the second moist hot air through hole 9, a groove 17 communicated with the reaction gas guiding groove 6 is arranged at a position corresponding to the reaction gas through hole 8 on the adjacent partition board on the side provided with the reaction gas guiding groove 6, both sides of the partition board 1 are also kept sealed by a sealing ring 16, and both sides of the partition board 1 are respectively provided with a humidifying membrane 4 to form two additional humidifying units corresponding to the adjacent partition board 3. The end plates 2 on both sides are respectively provided with a hot and humid air inlet 10 and a hot and humid air outlet 11 which are communicated with the first hot and humid air through hole 7, wherein the end plate 2 on one side is also provided with a first reaction gas inlet 12 and a first reaction gas outlet 13 which are communicated with the reaction gas through hole 8, and the end plate on the other side is provided with a second reaction gas inlet 14 and a second reaction gas outlet 15. The humidifying membrane 4 is a perfluorosulfonic acid membrane, but may be a membrane through which water passes but gas does not pass.

In example 1 shown in FIG. 6, the first reactive gas inlet 12 is higher than the first reactive gas outlet 13, the second reactive gas inlet 14 is higher than the first reactive gas outlet 15, and FIG. 7 is a flow diagram of the reactive gas in the humidifier in example 1.

In example 2 shown in fig. 8, the first reactive gas inlet 12 is lower than the first reactive gas outlet 13, the second reactive gas inlet 14 is lower than the first reactive gas outlet 15, and fig. 9 is a flow diagram of the reactive gases in the humidifier in example 2.

Fig. 10 is a flow diagram of the hot and humid air in the humidifier in the above two embodiments.

Claims

1. A fuel cell humidifier, characterized by: the humidifying device comprises a partition board (1), an end board (2) and a humidifying unit, wherein at least one humidifying unit is arranged on each of two sides of the partition board (1) and is clamped and fixed by the end board (2) on the outer side, and the humidifying unit comprises a guide plate (3) and a humidifying membrane (4). The two surfaces of each guide plate (3) are respectively provided with a damp and hot air guide groove (5) and a reaction gas guide groove (6), the guide plates (3) are also provided with a first damp and hot air through hole (7) communicated with the damp and hot air guide grooves (5) and a reaction gas through hole (8) communicated with the reaction gas guide grooves (6), one surface of one guide plate (3) provided with the damp and hot air guide grooves (5) and one surface of the other adjacent guide plate (3) provided with the reaction gas guide grooves (6) are clamped with a humidifying film (4) in the middle to form a humidifying unit; the baffle plate (1) is provided with a second damp and hot air through hole (9) communicated with the first damp and hot air through hole (7), the end plates (2) at two sides are respectively provided with adamp and hot air inlet (10) and a damp and hot air outlet (11) communicated with the first damp and hot air through hole (7), the end plate (2) at one side is also provided with a first reaction gas inlet (12) and a first reaction gas outlet (13) communicated with the reaction gas through hole (8), and the end plate at the other side is provided with a second reaction gas inlet (14) and a second reaction gas outlet (15).

2. A fuel cell humidifier according to claim 1, wherein: the two sides of the partition board (1) are respectively provided with a moist hot air diversion trench (5) and a reaction gas diversion trench (6), wherein the moist hot air diversion trench (5) on one side is communicated with a second moist hot air through hole (9), a groove (17) communicated with the reaction gas diversion trench (6) is arranged on the other side corresponding to the reaction gas through hole (8) on the adjacent guide board, and two sides of the partition board (1) are respectively provided with a humidifying membrane (4) to form two additional humidifying units corresponding to the adjacent guide board (3).

3. A fuel cell humidifier according to claim 1, wherein: the humidifying membrane (4) is a perfluorosulfonic acid membrane.