Two-stage back pressure valve cathode air pressure regulation architecture for fuel cells

Abstract

This invention relates to a two-stage back pressure valve cathode air pressure regulation architecture for fuel cells, comprising an air filter, an air compressor, an intercooler, a humidifier, and a fuel cell stack connected in sequence. The key feature is that a primary back pressure valve is installed on the air pipeline between the fuel cell stack and the humidifier, and a secondary back pressure valve is installed on the air pipeline after the humidifier. By installing a primary back pressure valve between the fuel cell stack and the humidifier, and a secondary back pressure valve after the humidifier, this invention achieves coordinated regulation of air pressure and humidity, effectively solving the problems of decoupling humidity and pressure control and poor responsiveness in existing technologies, and improving the stability and dynamic response capability of the fuel cell system.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen storage systems for new energy fuel cells, and specifically relates to a two-stage back pressure valve cathode air pressure regulation architecture for fuel cells. Background Technology

[0002] In current fuel cell air circuits, a back pressure valve is typically placed after the humidifier on the humidified air side. Its function is to regulate the upstream air pressure by using throttling to achieve the optimal air pressure under the operating conditions. However, there are two problems in this process: First, since most systems use a membrane humidifier structure, it is impossible to control the humidity of the intake air when regulating the air pressure using the back pressure valve. Second, due to the long air exhaust pipe of the fuel cell stack, the air pressure control response is not high. Summary of the Invention

[0003] This invention provides a two-stage back pressure valve cathode air pressure regulation architecture for fuel cells, which solves the problems of decoupling humidity and pressure control and poor responsiveness in the prior art.

[0004] To address the above technical problems, this invention provides a two-stage back pressure valve cathode air pressure regulation architecture for fuel cells, comprising an air filter, an air compressor, an intercooler, a humidifier, and a fuel cell stack connected in sequence. The invention is characterized by a first-stage back pressure valve installed on the air pipeline between the fuel cell stack and the humidifier, and a second-stage back pressure valve installed on the air pipeline after the humidifier.

[0005] Furthermore, the opening degrees of the primary back pressure valve and the secondary back pressure valve are adjusted according to the voltage status of each individual cell in the fuel cell stack collected by the fuel cell voltage monitor.

[0006] Furthermore, when the intake air humidity is insufficient, the first-stage back pressure valve is fully opened, and the opening of the second-stage back pressure valve is adjusted to increase the upstream air pressure.

[0007] Furthermore, when the intake air humidity is excessive, the secondary back pressure valve is fully opened, and the opening of the primary back pressure valve is adjusted to reduce the upstream air pressure.

[0008] Furthermore, the humidifier is a membrane humidifier.

[0009] Furthermore, both the primary back pressure valve and the secondary back pressure valve are electrically controlled proportional valves.

[0010] Furthermore, it also includes a controller for receiving signals from the fuel cell voltage inspector and controlling the opening degree of the primary back pressure valve and the secondary back pressure valve according to a preset strategy.

[0011] Furthermore, the controller determines the air humidity status based on the uniformity of the fuel cell voltage and dynamically adjusts the back pressure valve opening combination.

[0012] Furthermore, the air compressor is a centrifugal or screw air compressor.

[0013] Furthermore, the outlet of the secondary back pressure valve is connected to the atmosphere.

[0014] Beneficial effects: By setting a primary back pressure valve between the fuel cell stack and the humidifier and a secondary back pressure valve after the humidifier, the present invention achieves coordinated regulation of air pressure and humidity, effectively solving the problems of decoupling of humidity and pressure control and poor responsiveness in the prior art, and improving the stability and dynamic response capability of the fuel cell system. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the two-stage back pressure valve cathode air pressure regulation architecture in an embodiment of the present invention. Detailed Implementation

[0016] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below.

[0017] like Figure 1 As shown, the present invention proposes a two-stage back pressure valve cathode air pressure regulation architecture for fuel cells, comprising an air filter, an air compressor, an intercooler, a humidifier, and a fuel cell stack connected in sequence. The feature is that a first-stage back pressure valve is arranged in the air pipeline between the fuel cell stack and the humidifier, and a second-stage back pressure valve is arranged in the air pipeline after the humidifier.

[0018] The air supply circuit is routed as follows: ① Air filter ② Air compressor ③ Intercooler ④ Humidifier ⑤ Fuel cell stack ⑥ Primary back pressure valve ⑦ Humidifier ⑧ Secondary back pressure valve ⑨ Exhaust to atmosphere.

[0019] The working mode of the entire two-stage back pressure valve cathode air pressure regulation architecture is as follows: based on the voltage status of each single cell in the fuel cell stack collected by the fuel cell voltage monitor (CVM) (which indirectly reflects the degree of air intake humidification), the opening degree of the two-stage back pressure valve is controlled.

[0020] The specific implementation method is as follows: When the intake air humidity is insufficient, the first-stage back pressure valve is fully opened (minimum throttling effect), the opening of the second-stage back pressure valve is reduced, and the throttling effect of the second-stage back pressure valve is changed to regulate the air pressure upstream of the second-stage back pressure valve (the cathode side of the fuel cell stack and all air chambers of the humidifier). Under the effect of increased air pressure, the humidification degree of the intake air is improved. Conversely, when the intake air humidity is excessive (such as when the fuel cell stack is flooded, i.e., the electrode voltage at the front and rear ends of the fuel cell stack suddenly drops), the pressure upstream (the cathode side of the fuel cell stack and the dry air chamber of the humidifier) ​​is mainly regulated by reducing the opening of the first-stage back pressure valve. At the same time, the second-stage back pressure valve is in the fully open state (minimum throttling effect), and the humidity in the intake air of the fuel cell stack is reduced through reverse water transfer of the membrane.

[0021] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A two-stage back pressure valve cathode air pressure regulation architecture for fuel cells, comprising an air filter, an air compressor, an intercooler, a humidifier, and a fuel cell stack connected in sequence, characterized in that, A primary back pressure valve is installed on the air line between the fuel cell stack and the humidifier, and a secondary back pressure valve is installed on the air line after the humidifier.

2. The architecture according to claim 1, characterized in that, The opening degrees of the primary back pressure valve and the secondary back pressure valve are adjusted according to the voltage status of each individual cell in the fuel cell stack collected by the fuel cell voltage monitor.

3. The architecture according to claim 2, characterized in that, When the intake air humidity is insufficient, the first-stage back pressure valve is fully opened, and the opening of the second-stage back pressure valve is adjusted to increase the upstream air pressure.

4. The architecture according to claim 2, characterized in that, When the intake air humidity is excessive, the secondary back pressure valve is fully opened, and the opening of the primary back pressure valve is adjusted to reduce the upstream air pressure.

5. The architecture according to claim 1, characterized in that, The humidifier is a membrane humidifier.

6. The architecture according to claim 1, characterized in that, Both the primary back pressure valve and the secondary back pressure valve are electrically controlled proportional valves.

7. The architecture according to claim 1, characterized in that, It also includes a controller for receiving signals from the fuel cell voltage inspector and controlling the opening of the primary and secondary back pressure valves according to a preset strategy.

8. The architecture according to claim 7, characterized in that, The controller determines the air humidity status based on the uniformity of the fuel cell voltage and dynamically adjusts the back pressure valve opening combination.

9. The architecture according to claim 1, characterized in that, The air compressor is a centrifugal or screw air compressor.

10. The architecture according to claim 1, characterized in that, The outlet of the secondary back pressure valve is connected to the atmosphere.

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