CN110010928B - Fuel cell anode pressure protection device and control method thereof - Google Patents

Abstract

The invention relates to a fuel cell anode pressure protection device and a control method thereof, comprising a stack hydrogen inlet pipeline, the stack hydrogen inlet pipeline is connected to the fuel cell anode, and a pressure regulating valve and a pressure regulating valve are arranged on the stack hydrogen inlet pipeline. pressure sensor, the stack hydrogen inlet pipeline is provided with a bypass pressure relief pipeline, the bypass pressure relief pipeline is provided with a normally open solenoid valve and a mechanical pressure relief valve, and the stack outlet of the fuel cell anode The pipeline is connected to the pipeline of the mixing tank, the end of the bypass pressure relief pipeline is connected to the pipeline of the mixing tank, and a solenoid valve for discharging hydrogen is arranged between the outlet pipeline of the stack and the pipeline of the mixing tank. The device has low cost, high control precision, strong stability, and can realize automatic fuel cell anode pressure protection.

Description

A fuel cell anode pressure protection device and control method thereof

technical field

The invention relates to the technical field of fuel cells, in particular to a fuel cell anode pressure protection device and a control method thereof.

Background technique

A fuel cell is a power generation device that directly converts the chemical energy of fuel into direct current electrical energy. Its working principle is to convert the chemical energy of substances into electrical energy through electrochemical reaction, and the substances required for the chemical reaction of the fuel cell are constantly replenished from the outside. Simply put, a fuel cell is an energy conversion device.

Proton Exchange Membrane Fuel Cell (PEMFC) is an electrochemical power generation device that uses hydrogen as fuel and oxygen as oxidant. Due to the advantages of environmental friendliness and high energy conversion efficiency, it is considered to be the cleanest and most efficient new energy power generation device and is widely used in automobiles.

In order to guarantee the safety and durability of the fuel cell, the pressure difference between the anode and the cathode must be strictly limited. Especially for high pressure fuel cells, it is necessary to carefully control the pressure difference to avoid excessive stress on the proton exchange membrane. If the pressure difference between the cathode and anode cannot be effectively controlled, the life of the PEMFC will be reduced, and in severe cases, it will cause safety hazards. This is a limiting factor that hinders the commercialization of fuel cell-based electric vehicles.

The pressure at the anode increases faster than the pressure at the cathode because hydrogen is supplied to the anode through a high pressure tank, while the cathode is supplied with ambient air through a compressor with a larger manifold volume, requiring more time to increase the pressure. Therefore, in terms of response time, the anode pressure is typically set to track the cathode pressure to maintain the pressure difference between the cathode and anode within a certain range. Therefore, the control accuracy of anode pressure is crucial to ensure the safety and durability of fuel cells.

At present, there have been some studies on controlling anode pressure. For example, Karnik et al. designed a static output feedback controller that received the measured anode pressure and humidity signals and controlled an anode recirculation system-based injector to regulate anode pressure and humidity. [Karnik AY, Sun J, Stefanopoulou AG, Buckland JH. Humidity and pressure regulation in a PEM fuel cell using a gainscheduled static feedback controller. IEEE Trans Control Syst Technol 2009;17:283-97] However, the requirement for cathode water activity measurement makes The controller is difficult to implement. Pukrushpan et al. used a proportional controller based on pressure difference, so that the pressure in the anode can quickly track the pressure in the cathode [Pukrushpan JT, Stefanopoulou AG, Peng H. Control of fuel cell power systems: principles, modeling, analysis and feedback design. Springer Science & Business Media; 2004]. In reality, however, the proportional valve envisaged by Pukrushpan has steady-state errors and the problem of disturbing the suppression capability during purging remains unresolved. To sum up, so far, there is no fuel cell anode pressure protection device with low cost, high control precision, strong stability and automation.

Patent CN203839461U discloses a hydrogen fuel cell engine anode pressure control device, including a high-pressure hydrogen storage tank, a pressure reducing valve, a one-way valve, a common rail system, an electric stack, a hydrogen exhaust valve, an anode inlet pressure sensor, a cathode inlet pressure sensor and The pressure controller, the common rail system is mainly composed of N high-frequency solenoid valves; the pressure controller receives the command of the upper control (engine ECU) through CAN communication, and drives the common rail system sub-pipe solenoid according to the feedback information of the pressure sensor. The valve switch and hydrogen discharge valve can realize the pressure adjustment or hydrogen discharge action, but the main technical problem solved by this device is to stably and controllably transport the hydrogen supplied by the high-pressure hydrogen tank to the anode end of the battery, not for the abnormal operation of the system. Pressure control during states such as power outages.

SUMMARY OF THE INVENTION

The invention aims to solve the problem of precisely controlling the anode pressure when the fuel cell stack stops working abnormally (such as power failure), so as to ensure that the pressure difference between the anode and the cathode is controlled within a certain range, so as to protect the proton exchange membrane of the fuel cell. Provided are a fuel cell anode pressure protection device and a control method thereof, which have the advantages of low cost, high control precision, strong stability, and can realize automatic fuel cell anode pressure protection.

The object of the present invention is achieved through the following technical solutions:

A fuel cell anode pressure protection device, comprising a stack hydrogen inlet pipeline, the stack hydrogen inlet pipeline is connected to the fuel cell anode, a pressure regulating valve and a pressure sensor are arranged on the stack hydrogen inlet pipeline, and the stack hydrogen inlet pipeline is provided with a pressure regulating valve and a pressure sensor. The hydrogen inlet pipeline is provided with a bypass pressure relief pipeline, the bypass pressure relief pipeline is provided with a normally open solenoid valve and a mechanical pressure relief valve, and the stack outlet pipeline of the fuel cell anode is connected to the mixing tank pipeline, so The end of the bypass pressure relief pipeline is connected to the mixing tank pipeline, and a hydrogen discharge solenoid valve is arranged between the stack outlet pipeline and the mixing tank pipeline.

Further, the inlet end of the stack hydrogen inlet pipe is connected to the hydrogen supply unit.

Further, the outlet end of the mixing tank pipeline is connected to the hydrogen recovery tank.

Further, the normally open solenoid valve is installed on the side close to the hydrogen inlet pipeline of the stack, and the mechanical pressure relief valve is installed on the side close to the mixing tank pipeline.

A control method of a fuel cell anode pressure protection device, the device is used for fuel cell anode pressure protection, and the specific control method is:

During normal operation, the pressure sensor monitors the fuel cell anode pressure in real time. When the pressure difference between the fuel cell anode and the fuel cell cathode is higher than the set value, the hydrogen discharge solenoid valve is opened until the pressure difference falls to the set value;

When the fuel cell system is suddenly powered off or the hydrogen discharge solenoid valve fails, the normally open solenoid valve is opened, and the hydrogen is released through the bypass pressure relief pipeline. The mechanical pressure relief valve with a preset pressure value controls the fuel cell anode at the set within a certain pressure. Further, the pressure difference between the anode of the fuel cell and the cathode of the fuel cell is controlled within 0.5 bar.

The mechanical pressure relief valve needs to set a pressure relief threshold. At the same time, after the pressure relief valve in the system is opened, it does not need to be replaced due to the change of anode pressure control requirements. The effect of anode pressure. The pressure relief pressure can be easily modified in the system controller, which overcomes the disadvantage that the traditional anode pressure relief threshold must exceed the maximum anode pressure. The pressure sensor installed at the anode inlet of the stack is used to monitor the hydrogen pressure at the anode inlet of the stack and convert the pressure value. It is sent to the system controller and compared with the set value, thereby controlling the opening of the solenoid valve. Since the set value can be easily modified in the controller according to actual requirements, there is no need to replace the device, it is applicable to fuel cell systems of different power levels, and the system adaptability is strong.

In order to solve the technical problem that when the pressure difference between the cathode and anode of the fuel cell exceeds a certain range, the stress on the proton exchange membrane will increase significantly, thereby reducing the life of the PEMFC, and in severe cases, it will cause potential safety hazards, the present invention provides a fuel cell. The anode pressure protection device ensures that the difference between anode pressure and cathode pressure is strictly kept within a limited value, especially in the case of rapid fluctuation of cathode pressure, sudden power failure of the system, and failure of the pressure control device in the system. Therefore, a novel fuel cell anode pressure control system is obtained, which overcomes the disadvantage that the traditional anode pressure relief threshold must exceed the maximum anode pressure.

The technical solution adopted can control the anode pressure in the following three situations:

The first situation is that during normal operation, the rate of change of cathode pressure is too large. For the process of rapid increase of cathode pressure, the establishment speed of anode pressure is large enough to keep up with the increase of cathode pressure. For the process of the rapid decrease of the cathode pressure, the anode pressure cannot automatically decrease rapidly. At this time, the hydrogen discharge solenoid valve is opened to discharge the hydrogen gas to accelerate the decrease of the anode pressure, so as to ensure that the pressure difference between the anode and the cathode is within the allowable range. .

The second situation is the process of sudden power failure of the system. After the power failure, the normally open solenoid valve is opened, and the hydrogen flows into the mixing tank through the device. The pressure relief valve with a preset pressure value controls the anode pressure within the set pressure. Thus, the anode pressure is prevented from being too high, and the proton exchange membrane of the fuel cell is guaranteed not to be broken.

The third situation is the situation where the anode pressure is too high, for which two control strategies can be used to control the anode pressure:

1) The control strategy is suitable for the normal operation of the hydrogen discharge solenoid valve. When the anode pressure is too high due to the failure of a certain part of the system (such as the failure of the anode pressure regulating valve), the hydrogen discharge solenoid valve is opened, the anode pressure is reduced, and the pressure between the cathode and anode is reduced. The pressure difference is kept within a limited range, preventing breakage of the proton exchange membrane.

2) The control strategy is suitable for the situation that the hydrogen discharge solenoid valve cannot work normally. At this time, the anode hydrogen is difficult to discharge for a short time, resulting in excessive anode pressure. The control strategy in this situation is as follows: the normally open solenoid valve is powered off, the hydrogen flow is discharged through the pressure relief valve by opening the solenoid valve frequently, the anode pressure is reduced, and can be controlled within the limit value, so that the pressure difference between the cathode and anode It can be stored within a limited range, such as 0.5 bar, thus preventing breakage of the proton exchange membrane.

Description of drawings

Fig. 1 is the schematic diagram of the anode pressure protection device of the fuel cell of the present invention;

In the figure: 1-pressure sensor; 2-fuel cell cathode; 3-proton exchange membrane; 4-hydrogen discharge solenoid valve; 5-mixing tank pipeline; 6-fuel cell anode; 7-mechanical pressure relief valve; 8-normal Open solenoid valve; 9- pressure regulating valve; 10- stack hydrogen inlet pipeline; 11- bypass pressure relief pipeline; 12- stack outlet pipeline.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Referring to FIG. 1, a fuel cell anode pressure protection device is used for the pressure control of the fuel cell anode 6 to avoid the destruction of the proton exchange membrane 3 between the fuel cell cathode 2 and the fuel cell anode 6, and the device includes a stack hydrogen inlet pipeline 10 , the stack hydrogen inlet pipeline 10 is connected to the fuel cell anode 6, the stack hydrogen inlet pipeline 10 is provided with a pressure regulating valve 9 and a pressure sensor 1, and the stack hydrogen inlet pipeline 10 is provided with a bypass pressure relief pipeline 11. A normally open solenoid valve 8 and a mechanical pressure relief valve 7 are arranged on the bypass pressure relief pipeline 11. The stack outlet pipeline 12 of the fuel cell anode 6 is connected to the mixing tank pipeline 5, and the end of the bypass pressure relief pipeline 11 is connected to the mixing tank. A hydrogen discharge solenoid valve 4 is arranged between the pipeline 5 , the stack outlet pipeline 12 and the mixing tank pipeline 5 . The inlet end of the stack hydrogen inlet pipe 10 is connected to the hydrogen supply unit. The outlet end of the mixing tank pipeline 5 is connected to the hydrogen recovery tank. The normally open solenoid valve 8 is installed on the side close to the hydrogen inlet pipe 10 of the stack, and the mechanical pressure relief valve 7 is installed on the side close to the mixing tank pipe 5 .

The mechanical pressure relief valve 7 in the device does not need to precisely adjust the pressure setting value, and at the same time, the pressure relief valve 7 in the system does not need to be replaced due to changes in anode pressure control requirements after it is opened. The anode pressure control strategy involves a hydrogen discharge solenoid valve. One end of the hydrogen discharge solenoid valve 4 is installed on the stack outlet pipe, and the other end is installed on the mixing tank inlet pipe. By controlling the opening and closing of the hydrogen discharge solenoid valve, the hydrogen can be discharged reasonably and the anode pressure can be controlled.

The device can easily modify the relief pressure in the system controller, eliminating the need to replace the device during use. Through the pressure sensor 1 installed on the anode inlet pipe of the stack, the anode pressure is monitored in real time. When the difference between the anode pressure and the cathode pressure is higher than the set value, the hydrogen discharge solenoid valve 4 is opened, and the difference between the anode pressure and the cathode pressure falls back. When it is within the set value, close the hydrogen discharge solenoid valve 4. The set value can be set and changed according to the needs of use.

Example 1

This example provides an anode pressure control technique under normal operating conditions of the system. During the normal operation of the system, the pressure sensor 1 installed at the anode inlet of the stack is used to monitor the hydrogen pressure at the anode inlet of the stack, and the pressure value is sent to the system controller for comparison with the set value, thereby controlling the normally closed solenoid valve 4 's on. If the rate of change of the cathode pressure is too large, for the process of the rapid rise of the cathode pressure, the build-up speed of the anode pressure is large enough to keep up with the rise of the cathode pressure. For the process of the rapid decrease of the cathode pressure, the anode pressure cannot be automatically reduced rapidly. At this time, the normally closed solenoid valve 4 is opened to discharge hydrogen gas to accelerate the decrease of the anode pressure, thereby ensuring that the pressure difference between the anode and the cathode is within the allowable range.

Example 2

This example provides an anode pressure control technique in the event of a sudden system outage. After the system is powered off, the normally open solenoid valve 8 in the pressure relief protection device is opened, and the hydrogen flows into the inlet channel 5 of the mixing tank through the device. The pressure relief valve 7 with a preset pressure value controls the anode pressure within the set pressure. Thus, the anode pressure is prevented from being too high, and the proton exchange membrane of the fuel cell is guaranteed not to be broken.

Example 3

This example provides the anode pressure control technology corresponding to the situation that the anode pressure is too high and the hydrogen discharge solenoid valve 4 is working normally. When the anode pressure is too high due to the failure of the anode pressure regulating valve 9 of the system, the hydrogen discharge solenoid valve 4 is opened, the anode pressure is reduced, and the pressure difference between the cathode and anode can be kept within a limited range, thereby preventing the damage of the proton exchange membrane.

Example 4

This example provides an anode pressure control technology corresponding to the situation that the anode pressure is too high and the hydrogen discharge solenoid valve 4 cannot work normally. When the anode pressure regulating valve 9 fails and the anode pressure is too high, and the hydrogen discharge solenoid valve 4 cannot work normally at this time, in order to reduce the anode pressure in time, the normally open solenoid valve 8 in the device is powered off, and the hydrogen flow often opens the solenoid valve 8 is discharged through the pressure relief valve 7, and the anode pressure is reduced and can be controlled within a limited value, so that the pressure difference between the cathode and anode can be kept within a limited range, such as 0.5 bar, thereby preventing the damage of the proton exchange membrane.

The foregoing description of the embodiments is provided to facilitate understanding and use of the invention by those of ordinary skill in the art. It will be apparent to those skilled in the art that various modifications to these embodiments can be readily made, and the generic principles described herein can be applied to other embodiments without inventive step. Therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should all fall within the protection scope of the present invention.

Claims (5)

1. A fuel cell anode pressure protection device comprises a galvanic pile hydrogen inlet pipeline (10), the galvanic pile hydrogen inlet pipeline (10) is connected to a fuel cell anode (6), a pressure regulating valve (9) and a pressure sensor (1) are arranged on the galvanic pile hydrogen inlet pipeline (10), and the device is characterized in that,

a bypass pressure relief pipeline (11) is arranged on the pile hydrogen inlet pipeline (10), a normally open electromagnetic valve (8) and a mechanical pressure relief valve (7) are arranged on the bypass pressure relief pipeline (11), a pile outlet pipeline (12) of the fuel cell anode (6) is connected with a mixing tank pipeline (5), the tail end of the bypass pressure relief pipeline (11) is connected to the mixing tank pipeline (5), and a hydrogen discharge electromagnetic valve (4) is arranged between the pile outlet pipeline (12) and the mixing tank pipeline (5);

normally open solenoid valve (8) and install and be close to pile hydrogen inlet pipeline (10) one side, mechanical type relief valve (7) are installed and are being close to blending tank pipeline (5) one side, mechanical type relief valve (7) are mechanical type relief valve (7) of preset pressure value.

2. The fuel cell anode pressure protection device according to claim 1, wherein the inlet end of the stack hydrogen inlet pipe (10) is connected to a hydrogen supply unit.

3. A fuel cell anode pressure protection device according to claim 1, characterized in that the outlet end of the mixing tank pipe (5) is connected to a hydrogen recovery tank.

4. A control method of a fuel cell anode pressure protection device according to any one of claims 1 to 3, wherein the device is used for fuel cell anode pressure protection, and the specific control method is as follows:

the pressure sensor (1) monitors the pressure of the anode (6) of the fuel cell in real time during normal operation, and when the pressure difference between the anode (6) of the fuel cell and the cathode (2) of the fuel cell is higher than a set value, the hydrogen discharge electromagnetic valve (4) is opened until the pressure difference falls to the set value;

when the fuel cell system is suddenly powered off or the hydrogen discharge electromagnetic valve (4) breaks down, the normally open electromagnetic valve (8) is opened, hydrogen is discharged through the bypass pressure discharge pipeline (11), and the fuel cell anode (6) is controlled within the set pressure by the mechanical pressure release valve (7) with the preset pressure value.

5. The control method of the fuel cell anode pressure protection device according to claim 4, characterized in that the pressure difference between the fuel cell anode (6) and the fuel cell cathode (2) is controlled within 0.5 bar.

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