CN116632286A - A proton exchange membrane fuel cell water balance system and control method - Google Patents

Abstract

The invention discloses a proton exchange membrane fuel cell water balance system and a control method, wherein the system includes a fuel cell body, an anode air intake unit and a cathode air intake unit; the anode air intake unit is provided with a first humidifier; the cathode The air intake unit is provided with a second humidifier; the fuel cell body is provided with a first humidity sensor and a second humidity sensor, the first humidity sensor is used to detect the humidity of hydrogen entering the fuel cell body; the second humidity sensor is used to detect The humidity of the air entering the fuel cell body; it also includes a state early warning unit and a water balance control unit; the water balance control unit is electrically connected to the first humidifier, the second humidifier, the first humidity sensor, the second humidity sensor and the state early warning unit . The invention can maintain the water balance in the proton exchange membrane fuel cell, so that the water content of the fuel cell is at a better level.

Description

A proton exchange membrane fuel cell water balance system and control method

technical field

The invention relates to the technical field of fuel cell vehicles, in particular to a proton exchange membrane fuel cell water balance system and a control method.

Background technique

Proton exchange membrane fuel cells can convert hydrogen energy into electrical energy, which is an ideal energy source that can be used in fuel cell vehicles.

The proton exchange membrane fuel cell needs a certain water content during the working process. If the water content is too high or too low, the working efficiency of the proton exchange membrane will be affected. Therefore, in order to ensure the working efficiency of the proton exchange membrane, it is necessary to control the water content in the proton exchange membrane fuel cell. Furthermore, due to the different sources of water in the cathode and anode, and under the effects of electromigration, pressure difference, etc., the water in the anode will permeate to the cathode. In this case, it is easy to cause failures such as anode film dryness and cathode water flooding.

Therefore, how to maintain the water balance in the proton exchange membrane fuel cell is one of the important problems to be solved urgently by those skilled in the art.

Contents of the invention

The purpose of the present invention is to provide a kind of proton exchange membrane fuel cell water balance system and control method, to solve the deficiencies in the prior art, it can keep the water balance in the proton exchange membrane fuel cell, so that the water content of the fuel cell is at a relatively high level good level.

The invention provides a proton exchange membrane fuel cell water balance system, a fuel cell body, an anode air intake unit and a cathode air intake unit; the anode air intake unit is connected to the anode of the fuel cell body to supply the fuel Hydrogen gas of the battery body; the cathode air intake unit is connected to the cathode of the fuel cell body to supply air to the cathode of the fuel cell body;

Wherein, the anode air intake unit is provided with a first humidifier, and the first humidifier is used to humidify the hydrogen in the anode air intake unit;

The cathode air intake unit is provided with a second humidifier, and the second humidifier is used to humidify the air in the cathode air intake unit;

The fuel cell body is provided with a first humidity sensor and a second humidity sensor, the first humidity sensor is used to detect the humidity of the hydrogen entering the fuel cell body; the second humidity sensor is used to detect the hydrogen gas entering the fuel cell body Humidity of the air in the fuel cell body;

It also includes a state warning unit and a water balance control unit;

The water balance control unit is electrically connected to the first humidifier, the second humidifier, the first humidity sensor, the second humidity sensor, and a status warning unit;

The state early warning unit is used for early warning of the water balance state in the fuel cell body; the water balance control unit controls the first humidifier and the second humidifier according to the early warning result output by the early warning unit of humidification.

As for the proton exchange membrane fuel cell water balance system as described above, optionally, a third humidity sensor, a first pressure sensor, a second pressure sensor, a first flow meter, a second pressure sensor, and a third humidity sensor are also arranged in the fuel cell body. Second flow meter, third flow meter and current sensor;

The third humidity sensor is used to detect the humidity at the air outlet of the fuel cell body;

The first pressure sensor is used to detect the hydrogen pressure in the anode of the fuel cell body;

The second pressure sensor is used to detect the air pressure in the cathode of the fuel cell body;

The first flowmeter is used to detect the flow rate of hydrogen gas entering the hydrogen gas inlet of the fuel cell body;

The second flowmeter is used to detect the air flow rate entering the air inlet of the fuel cell body;

The third flowmeter is used to detect the air flow rate discharged from the air outlet of the fuel cell body;

The current sensor is used to detect the current of the fuel cell body;

The state warning unit is electrically connected to the first pressure sensor, the second pressure sensor, the first flow meter, the second flow meter and the current sensor;

The state warning unit is based on the first pressure sensor, the second pressure sensor, the first flow meter, the second flow meter, the first humidity sensor, the second humidity sensor and the The third humidity sensor is used to warn the water balance state of the fuel cell body, and output the warning result to the water balance control unit.

The proton exchange membrane fuel cell water balance system as described above, wherein, optionally, the state warning unit is used to calculate the water volume and water volume change rate in the fuel cell body, the water volume ratio of the anode and the cathode, and the water volume ratio Rate of change: pre-warning the water balance state according to the water volume in the fuel cell body, the rate of change of the water volume, the proportion of the water volume and the rate of change of the proportion of the water volume.

The proton exchange membrane fuel cell water balance system as described above, wherein, optionally, the state warning unit is based on the integral of the amount of water entering the fuel cell body during the working time and the integral of the amount of water discharged from the fuel cell during the working time. 1. Calculate the water volume in the fuel cell by integrating the speed of water produced by the fuel cell in the working hours.

The proton exchange membrane fuel cell water balance system as described above, wherein, optionally, the amount of water in the fuel cell body is calculated by the following formula,

Wherein, W _t is the amount of water in the fuel cell, _ρ1 is the detection result of the first humidity sensor, _Q1 is the detection result of the first flowmeter, _ρ2 is the detection result of the second humidity sensor, and _Q2 is the second flowmeter Detection results, _ρ3 is the detection result of the third humidity sensor, _Q3 is the detection result of the third flowmeter; c is a constant coefficient, and I is the detection result of the current sensor.

The proton exchange membrane fuel cell water balance system as described above, wherein, optionally, the water volume ratio in the fuel cell body is calculated by the following formula,

Among them, ω is the water volume ratio of the anode and the cathode, _ρ1 is the detection result of the first humidity sensor, _Q1 is the detection result of the first flowmeter, _ρ2 is the detection result of the second humidity sensor, and _Q2 is the second flowmeter Detection result, _ρ3 is the detection result of the third humidity sensor, _Q3 is the detection result of the third flowmeter; c is a constant coefficient, I is the detection result of the current sensor, S is the one-sided area of the proton exchange mode, and K is The permeability coefficient of the proton exchange module per unit area under unit pressure difference, P ₁ is the detection result of the first pressure sensor, and P ₂ is the detection result of the second pressure sensor.

In the proton exchange membrane fuel cell water balance system described above, optionally, the warning results of the state warning unit include: a first warning result, a second warning result, a third warning result, a fourth warning result and The fifth warning result;

When the water balance control unit obtains the first warning result, keep the humidification volumes of the first humidifier and the second humidifier unchanged;

When the water balance control unit obtains the second early warning result, increase the humidification capacity of the first humidifier and the humidification capacity of the second humidifier proportionally;

When the water balance control unit obtains the third warning result, reduce the humidification capacity of the first humidifier and the humidification capacity of the second humidifier in proportion, and increase the discharge capacity of the cathode;

When the water balance control unit obtains the four warning results, increase the cathode gas pressure of the fuel cell body to reduce the pressure difference between the anode gas and the cathode gas;

When the water balance control unit obtains the fifth warning result, it reduces the cathode gas pressure of the fuel cell body to increase the pressure difference between the anode gas and the cathode gas.

The proton exchange membrane fuel cell water balance system as described above, wherein, optionally, the state early warning unit is also used for,

When the water volume in the fuel cell body is within a first set range and the water volume ratio is within a second set range, a first warning result is output;

outputting a second warning result when the amount of water in the fuel cell body is less than the minimum value of the first setting range;

outputting the third warning result when the amount of water in the fuel cell body is greater than the maximum value of the first setting range;

outputting the fourth warning result when the proportion of water in the fuel cell body is smaller than the minimum value of the second setting range;

When the proportion of water in the fuel cell body is greater than the maximum value of the second setting range, the fifth warning result is output.

The present invention also proposes a water balance control method for a proton exchange membrane fuel cell, which includes the following steps,

The hydrogen pressure in the anode of the fuel cell body, the air pressure in the cathode of the fuel cell body, the hydrogen flow rate of the hydrogen inlet of the fuel cell body, the air flow rate of the air inlet of the fuel cell body, the air flow rate discharged from the air outlet of the fuel cell body and The current of the fuel cell body;

Calculate the water volume and water volume ratio in the fuel cell by integrating over the length of time;

Estimate the water balance state of the fuel cell according to the change of water volume and water volume ratio, and output the corresponding early warning results;

According to the early warning result, the humidification amount, pressure and cathode drainage of the fuel cell body are adjusted.

Compared with the prior art, the present invention detects the humidity of the hydrogen entering the fuel cell body, the humidity of the air entering the fuel cell body, the humidity at the air outlet of the fuel cell body, and the anode of the fuel cell body. The hydrogen pressure of the fuel cell body, the air pressure in the cathode of the fuel cell body, the hydrogen flow rate of the hydrogen inlet of the fuel cell body, the air flow rate of the air inlet of the fuel cell body, the air flow rate discharged from the air outlet of the fuel cell body, and the current of the fuel cell body, The water volume of the fuel cell body and the water volume ratio of the anode and the cathode are calculated by integrating the working hours. And according to the water volume and water volume ratio of the fuel cell body, the water balance state of the fuel cell is given an early warning, and the first humidifier, the second humidifier, and the air pressure at the inlet of the fuel cell body are controlled according to the early warning results, so that the proton The membrane fuel cell can be in a better water balance state, which is beneficial to ensure the high working efficiency of the proton membrane fuel cell.

Description of drawings

Fig. 1 is the structural representation of embodiment 1 of the present invention;

Fig. 2 is another kind of structural representation of embodiment 1 of the present invention;

Fig. 3 is a flowchart of the steps of Embodiment 2 of the present invention.

Explanation of reference signs:

1-Fuel cell body, 2-Anode intake unit, 3-Cathode intake unit, 4-Status warning unit, 5-Water balance control unit;

11-first humidity sensor, 12-second humidity sensor, 13-third humidity sensor, 14-first pressure sensor, 15-second pressure sensor, 16-first flow meter, 17-second flow meter, 18 - third flow meter, 19 - current sensor;

21 - first humidifier;

31 - Second humidifier.

Detailed ways

The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In a proton exchange membrane fuel cell, the decrease in the working efficiency of the proton exchange membrane due to water factors is mainly reflected in two aspects: one is the water content of the fuel cell, that is, the amount of water in the fuel cell; the other is the water content in the fuel cell. The water ratio between the anode and the cathode, due to factors such as electromigration, the pressure difference between the anode and the cathode, causes the moisture in the anode to migrate to the cathode, which leads to membrane dry failure or water flooding failure.

In order to avoid membrane dry failure and water flooding failure, and control the water volume in the fuel cell within a better range, the present invention proposes the following solutions.

Example 1

Please refer to Fig. 1 and Fig. 2, present embodiment proposes a kind of proton exchange membrane fuel cell water balance system, fuel cell body 1, anode air intake unit 2 and cathode air intake unit 3; The anode air intake unit 2 is connected to The anode of the fuel cell body 1 is used to supply hydrogen to the fuel cell body 1 ; the cathode air intake unit 3 is connected to the cathode of the fuel cell body 1 to supply air to the cathode of the fuel cell body 1 . Specifically, the anode air intake unit 2 and the cathode air intake unit 3 can be improved on the existing structure. For the convenience of explaining the implementation, only the improvements and some of the same parts will be described below.

Specifically, the anode air intake unit 2 is provided with a first humidifier 21 , and the first humidifier 21 is used to humidify the hydrogen in the anode air intake unit 2 . During specific implementation, that is, the first humidifier 21 is set as a humidifier with an adjustable humidification amount. The hydrogen gas entering the fuel cell body 1 is humidified by the first humidifier 21 , and then the anode of the fuel cell body 1 is humidified.

The cathode air intake unit 3 is provided with a second humidifier 31 for humidifying the air in the cathode air intake unit 3 . During specific implementation, that is, the second humidifier 31 is configured as a humidifier with an adjustable humidification amount. The air entering the fuel cell body 1 is humidified by the second humidifier 31 , and then the cathode of the fuel cell body 1 is humidified.

Furthermore, the fuel cell body 1 is provided with a first humidity sensor 11 and a second humidity sensor 12, the first humidity sensor 11 is used to detect the humidity of the hydrogen entering the fuel cell body 1; The second humidity sensor 12 is used to detect the humidity of the air entering the fuel cell body 1 . In practice, the first humidity sensor 11 and the second humidity sensor 12 are used to detect the humidity of the gas entering the fuel cell, so as to calculate the amount of water entering the fuel cell body 1 in the form of water molecules.

In order to warn and control the water balance state in the fuel cell body 1 , this embodiment further includes a state warning unit 4 and a water balance control unit 5 . The state warning unit 4 is used for warning the water balance state of the fuel cell and outputting the warning result to the water balance control unit 5 . The water balance control unit 5 is used to adjust the first humidifier 21 and the second humidifier 31 according to the warning result to control the water volume in the fuel cell.

Specifically, the water balance control unit 5 is electrically connected to the first humidifier 21 , the second humidifier 31 , the first humidity sensor 11 , the second humidity sensor 12 and the status warning unit 4 . The state warning unit 4 is used for warning the water balance state in the fuel cell body 1; the water balance control unit 5 uses the warning result output by the warning unit to control the first humidifier 21 and Humidification amount of the second humidifier 31.

During specific implementation, the state early warning unit 4 acquires the detection results of the first humidifier 21, the second humidifier 31, the first humidity sensor 11, and the second humidity sensor 12 in real time, and performs early warning according to the detection results, and Output the warning result. The water balance control unit 5 is used to adjust the state of the fuel cell body 1 in real time according to the warning result, so that the fuel cell body 1 is in a better water balance range.

In actual implementation, in order to accurately calculate the water quantity and water balance state in the fuel cell, this embodiment also monitors the discharged water, and at the same time, calculates electromigration and water penetration under pressure. For this reason, further improvements have been made in this embodiment. Specifically, a third humidity sensor 13, a first pressure sensor 14, a second pressure sensor 15, a first flow meter 16, A second flow meter 17 , a third flow meter 18 and a current sensor 19 .

Specifically, the third humidity sensor 13 is used to detect the humidity at the air outlet of the fuel cell body. The third humidity sensor 13 is installed at the air outlet of the fuel cell body 1 .

The first pressure sensor 14 is used to detect the hydrogen pressure in the anode of the fuel cell body 1; the first pressure sensor 14 is installed at the anode of the fuel cell body 1, and in specific implementation, the first pressure sensor 14 can be multiple, and the average value of the detection results of multiple first pressure sensors 14 can be used as the hydrogen pressure in the anode of the fuel cell body 1 .

The second pressure sensor 15 is used to detect the air pressure in the cathode of the fuel cell body 1; the second pressure sensor 15 is installed at the cathode of the fuel cell body 1, and in specific implementation, the second pressure sensor 15 can be multiple, and the average value of the detection results of multiple second pressure sensors 15 can be used as the hydrogen pressure in the cathode of the fuel cell body.

The first flow meter 16 is used to detect the hydrogen flow rate entering the hydrogen gas inlet of the fuel cell body 1 . The first flow meter 16 is used to calculate the amount of water entering the fuel cell body 1 along with the hydrogen gas in accordance with the detection result of the first humidity sensor 11 .

The second flowmeter 17 is used to detect the air flow rate entering the air inlet of the fuel cell body 1; of water.

The third flowmeter 18 is used to detect the air flow discharged from the air outlet of the fuel cell body 1 ; the third flowmeter 18 is used to calculate the amount of water discharged from the air outlet according to the detection result of the third humidity sensor 13 .

The current sensor 19 is used to detect the current of the fuel cell body 1; the battery sensor is used to calculate the amount of water moving from the anode to the cathode due to electromigration based on the detected battery.

The state warning unit 4 is electrically connected to the first pressure sensor 14 , the second pressure sensor 15 , the first flow meter 16 , the second flow meter 17 and the current sensor 19 respectively. During specific implementation, the state warning unit 4 can be directly connected with the first pressure sensor 14, the second pressure sensor 15, the first flow meter 16, the second flow meter 17 and the current The sensor 19 is electrically connected, or through the water balance control unit 5, to the first pressure sensor 14, the second pressure sensor 15, the first flow meter 16, and the second flow meter 17 respectively. It is electrically connected with the current sensor 19.

Specifically, the state warning unit 4 is based on the first pressure sensor 14, the second pressure sensor 15, the first flow meter 16, the second flow meter 17, the first humidity sensor 11, The second humidity sensor 12 and the third humidity sensor 13 give an early warning to the water balance state of the fuel cell body 1 and output the early warning result to the water balance control unit 5 .

Specifically, the state warning unit 4 is used to calculate the water volume and water volume change rate in the fuel cell body 1, the water volume ratio of the anode and the cathode, and the water volume ratio change rate; The rate of change, the proportion of water volume and the rate of change of water volume proportion give an early warning of the water balance state. In specific implementation, the early warning can be given only by the water volume in the fuel cell body 1 and the water volume ratio of the cathode, or by the water volume in the fuel cell body 1 and the rate of change of the water volume, the water volume ratio of the anode and the cathode, and The rate of change of water volume ratio is used for early warning. Compared with the early warning only based on the water volume in the fuel cell body 1 and the water volume ratio of the cathode, the early warning is obtained through the water volume in the fuel cell body 1 and the water volume change rate, the water volume ratio of the anode and the cathode, and the water volume ratio change rate. The result is more advanced and accurate.

Taking the early warning as an example only by the ratio of the water volume in the fuel cell body 1 to the water volume of the cathode, in specific implementation, the state early warning unit 4 discharges the fuel cell according to the integral of the water volume entering the fuel cell body 1 in the working hours. The integral of the amount of water in the working hours, the integral of the speed of water produced by the fuel cell in the working hours, is used to calculate the amount of water in the fuel cell. Specifically, the amount of water in the fuel cell body 1 is calculated by the following formula,

Wherein, W _t is the amount of water in the fuel cell, ρ ₁ is the detection result of the first humidity sensor 11, Q ₁ is the detection result of the first flowmeter 16, ρ ₂ is the detection result of the second humidity sensor 12, and Q ₂ is the detection result of the second humidity sensor 12. Two flowmeters 17 detection results, ρ ₃ is the detection result of the third humidity sensor 13, Q ₃ is the detection result of the third flowmeter 18; c is a constant coefficient, and I is the detection result of the current sensor 19. Among them, the constant coefficient c is related to the relationship between the passing current and the amount of charge and the number of water molecules carried by each charge when passing through the proton membrane.

Furthermore, the proportion of water in the fuel cell body 1 is calculated by the following formula,

Wherein, ω is the water volume ratio of the anode and the cathode, ρ ₁ is the detection result of the first humidity sensor 11, Q ₁ is the detection result of the first flowmeter 16, ρ ₂ is the detection result of the second humidity sensor 12, and Q ₂ is the detection result of the first humidity sensor 12. Two flowmeter 17 detection results, ρ ₃ is the detection result of the 3rd humidity sensor 13, Q ₃ is the detection result of the 3rd flow meter 18; c is a constant coefficient, I is the detection result of current sensor 19, S is the proton exchange mode K is the permeability coefficient of the proton exchange module per unit area under unit pressure difference, P ₁ is the detection result of the first pressure sensor 14, and P ₂ is the detection result of the second pressure sensor 15. In practice, the pressure of the anode should be higher than the pressure of the cathode, so as to prevent the air from the cathode from flowing into the anode.

More specifically, the warning results of the status warning unit 4 include: a first warning result, a second warning result, a third warning result, a fourth warning result and a fifth warning result. The first warning result, the second warning result, the third warning result, the fourth warning result and the fifth warning result are respectively used to characterize different fuel cell water balance states.

Specifically, the state early warning unit 4 is also used for:

When the water volume in the fuel cell body 1 is within the first set range and the water volume ratio is within the second set range, a first warning result is output; that is, the first warning result is used to represent the water volume And the water ratio is in the state of a better range.

When the amount of water in the fuel cell body 1 is less than the minimum value of the first setting range, a second warning result is output; that is, the second warning result is used to indicate that the water amount in the fuel cell body 1 is too low.

When the amount of water in the fuel cell body 1 is greater than the maximum value of the first setting range, the third warning result is output; that is, the third warning result is used to indicate that the amount of water in the fuel cell body 1 is too much .

When the proportion of water in the fuel cell body 1 is less than the minimum value of the second setting range, the fourth warning result is output; the fourth warning result is used to indicate that the water proportion is too low, that is, the anode Too much water or too little cathode water.

When the proportion of water in the fuel cell body 1 is greater than the maximum value of the second setting range, the fifth warning result is output. The fifth early warning result is used to represent the situation that the proportion of water is too large, that is, the situation of too much water at the anode or too little water at the cathode.

In specific implementation, the second early warning result and the third early warning result are determined by the water volume in the fuel cell, and the fourth early warning result and the fifth early warning result are determined by the ratio of the water volume. The second early warning result is superimposed with the fourth early warning result, the second early warning result is superimposed with the fifth early warning result, the third early warning result is superimposed with the fourth early warning result, and the third early warning result is superimposed with the fifth early warning result. When the superposition occurs, the superposition implements the corresponding control.

Specifically, when the water balance control unit 5 obtains the first warning result, the humidification amounts of the first humidifier 21 and the second humidifier 31 are kept unchanged. At this point, it is at the optimum moisture content and does not need to be changed by control.

When the water balance control unit 5 obtains the second warning result, the humidification capacity of the first humidifier 21 and the humidification capacity of the second humidifier 31 are increased proportionally. In practice, the ratio referred to here can be an allowable fixed value, or a variable value. When it is a variable value, the value can be determined according to the water volume ratio, so as to quickly adjust the water volume and the water volume ratio to the optimum.

When the water balance control unit 5 obtains the third warning result, it will reduce the humidification capacity of the first humidifier 21 and the humidification capacity of the second humidifier 31 in proportion, and increase the drainage of the cathode; during implementation, here The ratio referred to can be an allowed fixed value or a variable value. When it is a variable value, the value can be determined according to the water volume ratio, so as to quickly adjust the water volume and the water volume ratio to the optimum.

When the water balance control unit 5 obtains the four warning results, it increases the cathode gas pressure of the fuel cell body 1 to reduce the pressure difference between the anode gas and the cathode gas; when the water balance control unit 5 obtains the first When the pre-warning results, reduce the cathode gas pressure of the fuel cell body 1 to increase the pressure difference between the anode gas and the cathode gas. In practice, the pressure of the anode gas can be determined according to the demand for power generation. The control of the pressure of the cathode gas must meet the above control requirements on the one hand, and at the same time satisfy the pressure of the anode gas greater than the pressure of the cathode gas.

In specific implementation, when the water volume change rate and the water volume proportional change rate are used to participate in early warning, the first buffer area can be set at both ends of the first set range, and in the first buffer area, it is judged whether the water volume change rate is too large Or too small, when the water volume change rate is too large or too small, that is, when it is in the first buffer area, judge whether there is a trend that is about to exceed the first set range by the water volume change rate, so as to realize early judgment and early warning .

At the same time, a second buffer area is set at both ends of the second setting range, and in the second buffer area, it is judged whether the rate of change of the water volume ratio is too large or too small, when the rate of change of the water volume is too large or too small, that is, When it is in the second buffer area, it is judged by the change rate of the water volume ratio whether there is a trend of going beyond the second set range, so as to realize early judgment and early warning.

Example 2

Please refer to Fig. 3, the present embodiment proposes a kind of proton exchange membrane fuel cell water balance control method, comprises the following steps,

S1, collect the hydrogen pressure in the anode of the fuel cell body 1, the air pressure in the cathode of the fuel cell body 1, the hydrogen flow rate of the hydrogen gas inlet of the fuel cell body 1, the air flow rate of the air inlet of the fuel cell body 1, and the air flow rate of the fuel cell body 1. The air flow discharged from the air outlet and the current of the fuel cell body 1;

S2, calculating the water volume and water volume ratio in the fuel cell by integrating over the length of time;

S3, according to the change of water volume and water volume ratio, estimate the water balance state of the fuel cell, and output the corresponding early warning result;

S4, adjusting the humidification amount, pressure and cathode drainage of the fuel cell body 1 according to the warning result.

During specific implementation, this step is realized on the basis of Embodiment 1. Therefore, for the parts not mentioned in this embodiment, the implementation manner of Embodiment 1 may also be referred to.

The structure, features and effects of the present invention have been described in detail above based on the embodiments shown in the drawings. The above descriptions are only preferred embodiments of the present invention, but the present invention does not limit the scope of implementation as shown in the drawings. Changes made to the idea of the present invention, or modifications to equivalent embodiments that are equivalent changes, and still within the spirit covered by the description and illustrations, shall be within the protection scope of the present invention.

Claims (9)

1. A proton exchange membrane fuel cell water balance system comprises a fuel cell body, an anode air inlet unit and a cathode air inlet unit; the anode air inlet unit is connected with the anode of the fuel cell body so as to supply hydrogen to the fuel cell body; the cathode air inlet unit is connected to the cathode of the fuel cell body to supply air to the cathode of the fuel cell body;

the method is characterized in that: the anode air inlet unit is provided with a first humidifier, and the first humidifier is used for humidifying the hydrogen in the anode air inlet unit;

the cathode air inlet unit is provided with a second humidifier, and the second humidifier is used for humidifying the air in the cathode air inlet unit;

a first humidity sensor and a second humidity sensor are arranged in the fuel cell body, and the first humidity sensor is used for detecting the humidity of hydrogen entering the fuel cell body; the second humidity sensor is used for detecting the humidity of air entering the fuel cell body;

the system also comprises a state early warning unit and a water balance control unit;

the water balance control unit is electrically connected with the first humidifier, the second humidifier, the first humidity sensor, the second humidity sensor and the state early warning unit;

the state early warning unit is used for early warning the water balance state in the fuel cell body; and the water balance control unit is used for controlling the humidification amount of the first humidifier and the second humidifier according to the early warning result output by the early warning unit.

2. The proton exchange membrane fuel cell water balance system as claimed in claim 1, wherein: the fuel cell body is also internally provided with a third humidity sensor, a first pressure sensor, a second pressure sensor, a first flowmeter, a second flowmeter, a third flowmeter and a current sensor;

the third humidity sensor is used for detecting the humidity at the air outlet of the fuel cell body;

the first pressure sensor is used for detecting the pressure of hydrogen in the anode of the fuel cell body;

the second pressure sensor is used for detecting the air pressure in the cathode of the fuel cell body;

the first flowmeter is used for detecting the hydrogen flow entering the hydrogen inlet of the fuel cell body;

the second flowmeter is used for detecting air flow into an air inlet of the fuel cell body;

the third flowmeter is used for detecting the air flow discharged from the air outlet of the fuel cell body;

the current sensor is used for detecting the current of the fuel cell body;

the state early warning unit is respectively and electrically connected with the first pressure sensor, the second pressure sensor, the first flowmeter, the second flowmeter and the current sensor;

the state early warning unit early warns the water balance state of the fuel cell body according to the first pressure sensor, the second pressure sensor, the first flowmeter, the second flowmeter, the first humidity sensor, the second humidity sensor and the third humidity sensor, and outputs an early warning result to the water balance control unit.

3. The proton exchange membrane fuel cell water balance system as claimed in claim 2, wherein: the state early warning unit is used for calculating the water quantity and the water quantity change rate in the fuel cell body, the water quantity ratio of the anode and the cathode and the water quantity ratio change rate; and early warning the water balance state according to the water quantity, the water quantity change rate, the water quantity proportion and the water quantity proportion change rate in the fuel cell body.

4. A proton exchange membrane fuel cell water balance system as claimed in claim 3, wherein: the state early warning unit calculates the water quantity in the fuel cell according to the integral of the water quantity entering the fuel cell body on the working time, the integral of the water quantity discharged from the fuel cell on the working time and the integral of the speed of the water produced by the fuel cell on the working time.

5. The water balance system of a proton exchange membrane fuel cell as recited in claim 4, wherein: the amount of water in the fuel cell body is calculated by the following formula,

wherein W is _t ρ is the amount of water in the fuel cell ₁ Q is the detection result of the first humidity sensor ₁ For the first flowmeter detection result ρ ₂ Q is the detection result of the second humidity sensor ₂ For the second flowmeter measurement result ρ ₃ Q is the detection result of the third humidity sensor ₃ The detection result is the detection result of the third flowmeter; c is a constant coefficient, and I is a detection result of the current sensor.

6. The water balance system of a proton exchange membrane fuel cell as recited in claim 5, wherein: the water amount ratio in the fuel cell body is calculated by the following formula,

wherein ω is the water ratio of anode to cathode, ρ ₁ Q is the detection result of the first humidity sensor ₁ For the first streamMeter detection result ρ ₂ Q is the detection result of the second humidity sensor ₂ For the second flowmeter measurement result ρ ₃ Q is the detection result of the third humidity sensor ₃ The detection result is the detection result of the third flowmeter; c is a constant coefficient, I is a detection result of a current sensor, S is a single-side area of a proton exchange membrane, K is a permeability coefficient of the proton exchange membrane of a unit area under a unit pressure difference, and P ₁ P is the detection result of the first pressure sensor ₂ Is the detection result of the second pressure sensor.

7. The proton exchange membrane fuel cell water balance system as claimed in claim 6, wherein: the early warning result of the state early warning unit comprises: the first early warning result, the second early warning result, the third early warning result, the fourth early warning result and the fifth early warning result;

when the water balance control unit obtains a first early warning result, keeping the humidification amount of the first humidifier and the second humidifier unchanged;

when the water balance control unit obtains a second early warning result, the humidification amount of the first humidifier and the humidification amount of the second humidifier are increased proportionally;

when the water balance control unit obtains a third early warning result, the humidification amount of the first humidifier and the humidification amount of the second humidifier are proportionally reduced, and the drainage amount of the cathode is increased;

when the water balance control unit obtains four pre-warning results, increasing the cathode gas pressure of the fuel cell body so as to reduce the pressure difference between anode gas and cathode gas;

and when the water balance control unit obtains a fifth early warning result, reducing the cathode gas pressure of the fuel cell body so as to increase the pressure difference between the anode gas and the cathode gas.

8. The proton exchange membrane fuel cell water balance system as claimed in claim 7, wherein: the status pre-warning unit is also used for,

outputting a first early warning result when the water quantity in the fuel cell body is within a first set range and the water quantity proportion is within a second set range;

outputting a second early warning result when the water quantity in the fuel cell body is smaller than the minimum value of the first set range;

outputting the third early warning result when the water quantity in the fuel cell body is larger than the maximum value of the first set range;

outputting the fourth early warning result when the water quantity ratio in the fuel cell body is smaller than the minimum value of the second set range;

and outputting the fifth early warning result when the water quantity proportion in the fuel cell body is larger than the maximum value of the second set range.

9. A water balance control method of a proton exchange membrane fuel cell is characterized in that: comprises the steps of,

collecting the hydrogen pressure in the anode of the fuel cell body, the air pressure in the cathode of the fuel cell body, the hydrogen flow of the hydrogen inlet of the fuel cell body, the air flow of the air inlet of the fuel cell body, the air flow discharged by the air outlet of the fuel cell body and the current of the fuel cell body;

calculating the water quantity and the water quantity proportion in the fuel cell by integrating the water quantity and the water quantity proportion over the time length;

estimating the water balance state of the fuel cell according to the water quantity and the water quantity proportion, and outputting a corresponding early warning result;

and adjusting the humidification amount, the pressure and the cathode drainage amount of the fuel cell body according to the early warning result.