CN110021766A - A kind of fuel cell pack water management control system - Google Patents

Abstract

The invention discloses a fuel cell stack water management control system, which includes a cathode end, an anode end, gas flow paths on both sides, fuel gas, and oxidant gas. The anode end is provided with a solenoid valve combination, and the solenoid valve combination is controlled by controlling the solenoid valve combination. The fuel gas is made to pass through the anode-end gas flow path alternately with the upper-end intake and the lower-end outlet and the lower-end intake and the upper-end outlet alternately, so that the moisture inside the fuel cell stack is evenly distributed. The beneficial effects of the present invention are that the system power consumption is low; Low, only need to replace the solenoid valve; simple control strategy; reduce volume, save space, and improve the power density of the fuel cell stack system; bidirectional circulation of water in the anode flow channel inside the stack makes the water distribution more uniform, and solves the problem of fuel cell proximity The electrode at the entrance is easy to lose water and dry, and the electrode near the exit is easy to be flooded. This solution is not only suitable for open-cathode stacks, but also for closed-cathode stacks.

Description

A fuel cell stack water management control system

technical field

The invention relates to the technical field of fuel cells, in particular to a fuel cell stack water management control system.

Background technique

A fuel cell stack is a power generation device that directly converts the chemical energy of fuel into electrical energy. It has the advantages of high power density, no pollution, and low noise, and has broad application prospects. Fuel cells can be divided into proton exchange membrane fuel cells, direct methanol fuel cells, alkaline fuel cells, solid oxide fuel cells, molten salt fuel cells, microbial fuel cells, and the like.

When the fuel cell stack works, electrochemical reactions take place inside it. Take the proton exchange membrane fuel cell PEMFC as an example. With hydrogen as fuel, the electrode reaction of PEMFC is as follows:

Anode: H ₂ → 2H ⁺ +2e ^-

Cathode: ½O ₂ +2H ⁺ +2e ^- →H ₂ O

It can be seen from the electrode reaction that in PEMFC, the anode reactant gas hydrogen is passed into the anode flow channel. After the reaction gas is introduced into the battery, it is dissociated into protons and electrons under the action of the catalyst. The protons reach the cathode of the battery through the proton exchange membrane, and the electrons are collected by the current collector plate to perform work on the external circuit; the oxygen passes through the gas diffusion layer to reach the catalytic side of the cathode. On the surface, under the action of the catalyst, the oxygen combines with the protons passing through the proton exchange membrane and the electrons in the external circuit to form water, which releases a lot of heat.

In this process, in order to maintain the performance, reliability and life of the battery stack, the inside of the stack, especially the membrane electrodes, needs to have a certain water content to ensure good proton conductivity of the membrane, otherwise the membrane is easy to dehydrate and shrink seriously, affecting the protons Conduction; at the same time, the water should not be too much. If the water content of the membrane is too much, the water will flood the electrode, causing the electrode to flood. At the same time, the non-uniformity of water distribution in the internal environment of the fuel cell during operation leads to the fact that the electrode near the inlet part of the fuel cell is easy to lose water and dry, resulting in an increase in local internal resistance, and the electrode near the outlet part is easily flooded, making the fuel cell stack. Performance, reliability, longevity are all affected.

In order to solve such problems, the method of adding a hydrogen circulation pump is adopted in the system structure, which has the disadvantages of large volume and weight, high power consumption and high cost, and can only circulate in one direction, which does not fundamentally solve the fuel cell stack. The problem of uneven distribution of internal water has a great impact on stability and reliability. In the prior art, a water management control system for a self-humidifying fuel cell stack described in patent 201720491876.X is used in this solution. One additional port and one exhaust port are added, and there are no cathode air inlets and exhaust ports, so it is only suitable for open-cathode stacks, not for closed-cathode stacks.

SUMMARY OF THE INVENTION

In order to solve the above problems, the present invention provides a fuel cell stack water management and control system, in which the top-in, bottom-out and bottom-in, top-out modes of hydrogen can be converted to each other, so that the distribution of water in the anode flow channel of the fuel cell tends to be balanced, thereby increasing the fuel consumption. The reliability and life of the battery, this solution is not only suitable for open cathode stacks, but also for closed cathode stacks.

The technical solution solved by the present invention is to provide a fuel cell stack water management control system, including a cathode end, an anode end, gas flow paths on both sides, a fuel gas, and an oxidant gas, characterized in that the anode end is provided with a solenoid valve combination The upper part of the anode end is provided with a first air port, and the lower part of the anode end is provided with a second air port. The second vent port takes in air and the first vent port exits the gas, and the cathode end is provided with an air outlet and an air inlet for oxidant gas only.

Preferably, the solenoid valve combination includes one of a first solenoid valve combination, a second solenoid valve combination, and a third solenoid valve combination.

Preferably, the first solenoid valve combination includes a first one-way solenoid valve, a second one-way solenoid valve, a third one-way solenoid valve 313, a fourth one-way solenoid valve, a first three-way solenoid valve, a second three-way solenoid valve, The first one-way solenoid valve is the first intake valve port, the second one-way solenoid valve is the second intake valve port, the third one-way solenoid valve is the purge valve port, and the fourth one is the intake valve port. The valve port is the exhaust valve port, the first one-way solenoid valve and the second one-way solenoid valve are connected to the fuel gas supply equipment, one end of the first three-way solenoid valve and one end of the second three-way solenoid valve are connected in parallel to the upper end of the anode, the first One end of the three-way solenoid valve and the other end of the second three-way solenoid valve are connected in parallel with the lower end of the anode. Open one end of the first three-way solenoid valve and one end of the second three-way solenoid valve, and the fuel gas enters through the upper end of the anode and exits the lower end of the anode; open one end of the first three-way solenoid valve and the other end of the second three-way solenoid valve, the fuel gas passes through The lower end of the anode enters the air and the upper end of the anode exits.

Preferably, the second solenoid valve combination includes a first three-in, two-out solenoid valve, a fifth one-way solenoid valve, and a sixth one-way solenoid valve, and the first three-in, two-out solenoid valve is provided with a first air intake a valve port, a second intake valve port, and a third purge valve port, one end of the first intake valve port is connected to the fuel gas supply equipment, and the fifth one-way solenoid valve is connected in parallel with the other end of the first intake valve port At the upper end of the anode, one end of the second intake valve port is connected to the fuel gas supply equipment, the sixth one-way solenoid valve is connected to the lower end of the anode in parallel with the other end of the second intake valve port, and the first intake valve port is opened to close the second intake valve. At the gas valve port, the fuel gas enters the upper end of the anode and exits the lower end of the anode; the second intake valve port is opened to close the first intake valve port, and the fuel gas enters the lower end of the anode and exits the upper end of the anode.

Preferably, the third solenoid valve combination includes a seventh one-way solenoid valve, an eighth one-way solenoid valve, a first three-position five-way solenoid valve, a second three-position five-way solenoid valve, and the seventh single-way solenoid valve is a blower solenoid valve. Sweep valve, the right end and lower end of the first three-position five-way solenoid valve are respectively connected to the upper and lower ends of the anode, and the intake direction is controlled by the first three-position, five-way valve. The right end and the upper end of the second three-position five-way solenoid valve are respectively connected to the upper end and the lower end of the anode, and the exhaust direction is controlled by the second three-position five-way valve. Open the right end of the 1/3 5-way solenoid valve and the right end of the second 3/3 5-way solenoid valve, and the fuel gas will be discharged through the upper end of the anode and the lower end of the anode; open the upper end of the 1/3 5-way solenoid valve and the second 5/3-way solenoid valve At the lower end, the fuel gas enters the lower end of the anode and exits the upper end of the anode.

The beneficial effects of the invention are that the power consumption of the system is low; the cost is low, only the solenoid valve needs to be replaced; the control strategy is simple; the volume is reduced, the space is saved, and the power density of the fuel cell stack system is improved; , make the water distribution more uniform, solve the problem that the electrode near the inlet part of the fuel cell is easy to lose water and dry, and the electrode near the outlet part is easy to be flooded. This solution is not only suitable for open cathode stacks, but also for closed cathode stacks .

attached drawing

Fig. 1 is the internal moisture distribution diagram of the prior art fuel cell stack;

2 is a schematic diagram of the intake air of the fuel cell stack in Example 2;

3 is a schematic diagram of the intake air of the fuel cell stack in Example 3;

4 is a schematic diagram of the intake air of the fuel cell stack in Example 4;

In the figure: 1. Cathode end; 2. Anode end; 3. Solenoid valve combination; 4. First vent; 5. Second vent; 6, Air outlet; 7, Air inlet; 311, First one-way Solenoid valve; 312, second one-way solenoid valve; 313, third one-way solenoid valve; 314, fourth one-way solenoid valve; 315, first three-way solenoid valve; 316, second three-way solenoid valve; 321, The first three-in-two-out solenoid valve; 322, the fifth one-way solenoid valve; 323, the sixth one-way solenoid valve; 331, the seventh one-way solenoid valve; 332, the first three-position five-way solenoid valve; 333, the first one-way solenoid valve 2/3 5-way solenoid valve.

Detailed ways

In order to make the content of the present invention easier to understand, the technical solutions of the present invention will be further described below with reference to specific embodiments, but the present invention is not limited thereto.

Example 1

As shown in Figure 1, it is a diagram of the internal moisture distribution of the fuel cell stack in the prior art, specifically a closed cathode stack. The hydrogen content in the flow channel is continuously increasing on the path from the hydrogen inlet to the hydrogen outlet. At the same time, due to The anode is not humidified, so the hydrogen inlet humidity gradually decreases with the continuous entry of hydrogen, while the hydrogen outlet humidity increases with the increase of the water content in the flow channel, so the dry area and wet area shown in the figure appear. The non-uniformity of the water distribution in the internal environment of the fuel cell during operation leads to the fact that the electrode near the inlet part of the fuel cell is easy to lose water and dry, resulting in an increase in local internal resistance, and the electrode near the outlet part is easily flooded, which makes the performance of the fuel cell stack. Reliability and longevity are affected.

Example 2

As shown in FIG. 2, a fuel cell stack water management and control system, 1. A fuel cell stack water management and control system, comprising a cathode end 1, an anode end 2, gas flow paths on both sides, fuel gas, and oxidant gas, which It is characterized in that the anode end 1 is provided with a solenoid valve assembly 3, the upper portion of the anode end 1 is provided with a first vent 4, and the lower portion of the anode end 1 is provided with a second vent 5, by controlling the solenoid valve assembly 3 to make the fuel gas Intake from the first vent 4 and exit from the second vent 5, or allow fuel gas to enter from the second vent 5 and exit from the first vent 4, the cathode end 2 is provided with an outlet for oxidant gas only 6 and the air inlet 7, by controlling the solenoid valve combination 3, the fuel gas is hereinafter referred to as the upper inlet and the lower outlet, and the lower inlet and the upper outlet are hereinafter referred to as the lower inlet and the upper outlet alternately pass through the anode end 2. gas flow path, so that the moisture inside the fuel cell stack is evenly distributed, the fuel gas is hydrogen, and the oxidant gas is air. In this solution, when the first vent 4 is the air inlet 6, the second vent 5 is the air outlet 7, and vice versa.

The solenoid valve combination 3 includes one of a first solenoid valve combination 3, a second solenoid valve combination 3, and a third solenoid valve combination 3. In this embodiment, the first solenoid valve combination 3 is preferred. The specific structure and operation are as follows:

The first solenoid valve combination 3 includes a first one-way solenoid valve 311, a second one-way solenoid valve 312, a third one-way solenoid valve 313, a fourth one-way solenoid valve 314, a first three-way solenoid valve 315, and a third one-way solenoid valve 315. The two-way solenoid valve 316, the first one-way solenoid valve 311 is the first intake valve port, the second one-way solenoid valve 312 is the second intake valve port, and the third one-way solenoid valve 313 is the purge valve The valve port, the fourth one-way solenoid valve 314 is the exhaust valve port, the first one-way solenoid valve 311 and the second one-way solenoid valve 312 are connected to the fuel gas supply equipment, and one end of the first three-way solenoid valve 315 is connected to the second three-way solenoid valve 315. One end of the solenoid valve 316 is connected in parallel with the upper end of the anode, and one end of the first three-way solenoid valve 315 and the other end of the second three-way solenoid valve 316 are connected in parallel with the lower end of the anode. Open one end of the first three-way solenoid valve 315 and one end of the second three-way solenoid valve 316, and the fuel gas enters the lower end of the anode through the upper end of the anode and exits the anode; open one end of the first three-way solenoid valve 315 and the other end of the second three-way solenoid valve 316 , the fuel gas enters the lower end of the anode and exits the upper end of the anode.

The method adopted in this scheme uses the solenoid valve to control the intake of hydrogen from the upper end of the anode or the lower end of the anode to realize the transition of hydrogen in and out and down in and out, and only one air inlet 7 and one exhaust port are needed on the anode side, and no The addition of an air inlet 7 and an air outlet leaves space for the cathode air inlet 7 and the air outlet. The cathode end 1 is only used for the inlet and outlet of oxidant gas, which is not only suitable for open cathode stacks, The same applies to closed cathode stacks.

Embodiment 2 also includes a timing switch unit to change the flow direction of the fuel gas. This unit is a well-known product, and is used to regularly adjust the direction of the hydrogen in and out and the direction of the bottom in and out to avoid water accumulation.

Example 3

As shown in FIG. 3, a fuel cell stack water management control system includes a cathode end 1, an anode end 2, gas flow paths on both sides, fuel gas, and oxidant gas. The anode end 2 is provided with a solenoid valve assembly 3, and the The solenoid valve combination 3 is controlled so that the fuel gas passes through the gas flow path at the anode end 2 in an alternating manner of lower inlet and upper outlet, hereinafter referred to as upper inlet and lower outlet, and lower inlet and upper outlet. The moisture inside is evenly distributed, the fuel gas is hydrogen, and the oxidant gas is air.

The solenoid valve combination 3 includes one of a first solenoid valve combination 3, a second solenoid valve combination 3, and a third solenoid valve combination 3. In this embodiment, the second solenoid valve combination 3 is preferred. The specific structure and operation are as follows:

The second solenoid valve combination 3 includes a first three-in, two-out solenoid valve 321, a fifth one-way solenoid valve 322, and a sixth one-way solenoid valve 323. The first three-in, two-out solenoid valve 321 is provided with a first three-in, two-out solenoid valve 321. The intake valve port, the second intake valve port, and the third purge valve port, one end of the first intake valve port is connected to the fuel gas supply equipment, and the fifth one-way solenoid valve 322 is connected to the first intake valve port. The other end is connected in parallel to the upper end of the anode, one end of the second intake valve port is connected to the fuel gas supply equipment, the sixth one-way solenoid valve 323 and the other end of the second intake valve port are connected in parallel to the lower end of the anode, and pass through the The three purge valve ports are used to purge the anode of the stack. After purging is completed, close the third purge valve port, and the air end of the fuel cell operates normally. During 0- _t1 , open the first intake valve port, close the second intake valve port, and close the fifth one-way solenoid valve 322 After that, hydrogen enters from the gas supply equipment through the first intake valve port, enters the fuel cell stack through the upper end of the anode and is discharged from the lower end of the anode. After the gas valve port closes the first intake valve port and closes the sixth one-way valve, hydrogen enters from the gas supply equipment through the second intake valve port, enters the fuel cell stack through the lower end of the anode and is discharged from the upper end of the anode. The lower end is connected with the second intake valve port, so as to realize the conversion of the upper in and the lower out and the lower in and the upper out.

The method adopted in this scheme realizes the transition of hydrogen in and out and down in and out through the control of the solenoid valve. Only one air inlet 7 and one exhaust port are needed on the anode side, and additional air inlets 7 and exhaust ports are not required. This leaves space for the cathode inlet 7 and the exhaust port, and the cathode end 1 is only used for the inlet and outlet of the oxidant gas.

Embodiment 3 also includes a timing switching unit to change the flow direction of the fuel gas. This unit is a well-known product, and is used to regularly adjust the direction of hydrogen in and out and down in and out to avoid water accumulation.

Example 4

As shown in FIG. 4 , a fuel cell stack water management control system includes a cathode end 1, an anode end 2, gas flow paths on both sides, fuel gas, and oxidant gas. The anode end 2 is provided with a solenoid valve assembly 3, and the The solenoid valve combination 3 is controlled so that the fuel gas passes through the gas flow path at the anode end 2 in an alternating manner of lower inlet and upper outlet, hereinafter referred to as upper inlet and lower outlet, and lower inlet and upper outlet. The moisture inside is evenly distributed, the fuel gas is hydrogen, and the oxidant gas is air.

The solenoid valve combination 3 includes one of a first solenoid valve combination 3, a second solenoid valve combination 3, and a third solenoid valve combination 3. In this embodiment, the second solenoid valve combination 3 is preferred. The specific structure and operation are as follows:

The third solenoid valve combination 3 includes a seventh one-way solenoid valve 331, a first three-position, five-way solenoid valve 332, and a second three-position, five-way solenoid valve 333. The seventh one-way solenoid valve is a purge valve, and the first three-way solenoid valve is a purge valve. The right end and the lower end of the 5-way solenoid valve 332 are respectively connected to the upper end and the lower end of the anode, and the intake direction is controlled by the first 3-position 5-way valve. The right end and the upper end of the second three-position, five-way solenoid valve 333 are respectively connected to the upper end and the lower end of the anode, and the exhaust direction is controlled by the second three-position, five-way valve. Open the right end of one three-position five-way solenoid valve and the right end of the second three-position five-way solenoid valve 333, and the fuel gas enters the anode through the upper end of the anode and exits the lower end of the anode; open the upper end of one three-position five-way solenoid valve and the second three-position five-way solenoid valve. At the lower end of 333, the fuel gas enters the lower end of the anode and exits the upper end of the anode.

The method adopted in this scheme realizes the transition of hydrogen in and out and down in and out through the control of the solenoid valve. Only one air inlet 7 and one exhaust port are needed on the anode side, and additional air inlets 7 and exhaust ports are not required. This leaves space for the cathode inlet 7 and the exhaust port, and the cathode end 1 is only used for the inlet and outlet of the oxidant gas.

Embodiment 4 also includes a timing switching unit to change the flow direction of the fuel gas. This unit is a well-known product, and is used to regularly adjust the direction of the hydrogen in and out and the direction of the bottom in and out, so as to avoid water accumulation.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (5)

1. A fuel cell stack water management control system, comprising a cathode end (1), an anode end (2), gas flow paths on both sides, fuel gas, and oxidant gas, characterized in that the anode end (2) is provided with The solenoid valve assembly (3) is provided with a first ventilation port (4) at the upper part of the anode end (2) and a second ventilation port (5) at the lower part of the anode end (2). The fuel gas is taken in from the first vent port (4) and discharged from the second vent port (5), or the fuel gas is taken in from the second vent port (5) and discharged from the first vent port (4). (1) There is an outlet (6) and an inlet (7) for oxidant gas only. 2. A fuel cell stack water management control system according to claim 1, wherein the solenoid valve combination (3) comprises a first solenoid valve combination (31), a second solenoid valve combination (32), One of the third solenoid valve combinations (33). 3. A fuel cell stack water management control system according to claim 2, wherein the first solenoid valve combination (31) comprises a first one-way solenoid valve (311) and a second one-way solenoid valve (312), third one-way solenoid valve (313), fourth one-way solenoid valve (314), first three-way solenoid valve (315), second three-way solenoid valve (316), first one-way solenoid valve (311) and the second one-way solenoid valve (312) are connected to the fuel gas supply equipment. One end of the first three-way solenoid valve (315) and one end of the second three-way solenoid valve (316) are connected in parallel to the upper part of the anode end. One end of the solenoid valve (315) and the other end of the second three-way solenoid valve (316) are connected in parallel to the lower part of the anode end (2), and one end of the first three-way solenoid valve (315) and the second three-way solenoid valve (316) are opened. At one end, the fuel gas exits through the anode end (2), the first vent port (4), and the second vent port (5); At the other end, the fuel gas enters the first vent (4) and exits through the second vent (5). 4. The fuel cell stack water management control system according to claim 2, wherein the second solenoid valve combination (32) comprises a first three-in-two-out solenoid valve (321), a fifth one-way valve A solenoid valve (322) and a sixth one-way solenoid valve (323), the first three-in-two-out solenoid valve (321) is provided with a first intake valve port (34) and a second intake valve port (35) , a third purge valve port (36), one end of the first intake valve port (34) is connected to the fuel gas supply equipment, and the fifth one-way solenoid valve (322) is connected to the first intake valve port (34) The other end is connected in parallel to the upper part of the anode end (2), one end of the second intake valve port (35) is connected to the fuel gas supply equipment, and the sixth one-way solenoid valve (323) is connected to the other end of the second intake valve port (35) Connected in parallel to the lower part of the anode end (2), the first intake valve port (34) is opened and the second intake valve port (35) is closed, and the fuel gas enters the second ventilation through the anode end (2) first air port (4) The second air inlet valve port (35) is opened and the first air inlet valve port (34) is closed, and the fuel gas enters the first air inlet port (4) through the anode end second air port (5) and exits. 5. The fuel cell stack water management control system according to claim 2, wherein the third solenoid valve (33) combination comprises a seventh one-way solenoid valve (331), a first three-position five-way The solenoid valve (332), the second three-position five-way solenoid valve (333), the seventh one-way solenoid valve is a purge valve (334), and the valve ports of the first three-position five-way solenoid valve (332) are respectively connected to the first one-way solenoid valve (332). The air port (4) and the second air port (5), the gas gas is controlled by the first three-position five-way solenoid valve (332) to control the intake of the first air port (4) or the second air port (5). The right end and the upper part of the 2/3 5-way solenoid valve (333) are respectively connected to the upper and lower parts of the anode end (2). The right end of the valve (332) and the right end of the second three-position five-way solenoid valve (333), the fuel gas enters the second air port (5) through the first air port (4) and exits; open the first three-position five-way solenoid valve ( 332) the upper part and the lower part of the second three-position five-way solenoid valve (333), the fuel gas enters the first air port (4) and exits through the second air port (5).