WO2021258704A1

WO2021258704A1 - Current-based method for controlling opening frequency of hydrogen discharging valve and water drain valve

Info

Publication number: WO2021258704A1
Application number: PCT/CN2020/141496
Authority: WO
Inventors: 马秋玉; 赵洪辉; 鲍金成; 都京; 丁天威; 黄兴; 曲禄成; 王宇鹏; 秦晓津; 芦岩
Original assignee: 中国第一汽车股份有限公司
Priority date: 2020-06-24
Filing date: 2020-12-30
Publication date: 2021-12-30
Also published as: CN111799488A; CN111799488B

Abstract

Disclosed is a current-based method for controlling the opening frequency of a hydrogen discharging valve and a water drain valve. According to different current ranges, opening periods and opening time of a water drain valve and a hydrogen discharging valve are respectively controlled, thereby improving the utilization rate of hydrogen. For the opening period of the hydrogen discharging valve, the opening period is different in different current ranges, and for the opening time of the hydrogen discharging valve, the opening time is different in the different current ranges. For the opening period of the water drain valve, the opening period is the same in the different current ranges, and for the opening time of the water drain valve, the opening time is different in the different current ranges.

Description

Method for controlling opening frequency of hydrogen discharge valve and drain valve based on electric current

Technical field

The invention relates to a method for controlling the opening frequency of a hydrogen exhaust valve and a drain valve, in particular to a method for controlling the opening frequency of a hydrogen exhaust valve and a drain valve based on electric current.

Background technique

The fuel cell system may have excessive humidity under certain circumstances and is extremely prone to flooding. Therefore, a drain solenoid valve must be integrated in the general stack or system.

Since a large amount of nitrogen exists at the cathode for a long time and there is a certain concentration difference between the cathode and the anode, the nitrogen will diffuse from the cathode to the anode for a certain period of time, causing the anode hydrogen concentration to decrease. Therefore, hydrogen must be discharged regularly to ensure the anode hydrogen concentration to ensure voltage stability.

It is difficult to drain and discharge hydrogen from the anode at the same time. Therefore, before draining and discharging hydrogen, a water separator is integrated to separate hydrogen and water in advance, and then the water and hydrogen are discharged from the system through different channels.

Regarding the hydrogen discharge frequency, the existing schemes mostly use a fixed hydrogen discharge frequency, and it is impossible to flexibly adjust the hydrogen discharge frequency according to different efficiencies.

Patent Document 1 discloses a fuel cell anode intermittent hydrogen discharge system and a control method thereof. The control method includes: real-time monitoring of the voltage of the fuel cell stack and the nitrogen concentration at the anode outlet of the fuel cell stack; When the voltage drop of the fuel cell stack during the period when the anode hydrogen discharge is off is greater than the preset pressure drop threshold, the hydrogen at the anode outlet of the fuel cell stack is controlled to start to discharge; when it is determined that the fuel cell stack anode outlet When the nitrogen concentration of is less than the preset nitrogen concentration threshold, the hydrogen discharge from the anode outlet of the fuel cell stack is controlled to stop. The hydrogen exhaust system and the control method thereof can improve the hydrogen utilization efficiency of the fuel cell system on the basis of maintaining the stability of the fuel cell stack voltage.

Patent Document 2 discloses a hydrogen exhaust system for a proton exchange membrane fuel cell that can be quickly opened at low temperatures, including: a hydrogen exhaust pipe, a hydrogen exhaust valve, a coolant branch, and a liquid injection valve. The hydrogen exhaust pipe includes an inlet pipe. The two are connected by a hydrogen exhaust valve, and the air inlet of the inlet pipe is connected with the fuel cell stack; the inlet pipe of the hydrogen exhaust pipe and the coolant branch are connected by a liquid injection valve, and the coolant Coolant can be injected into the other end of the branch. The invention takes advantage of the low freezing point of the fuel cell system coolant, covers and protects the hydrogen discharge pipeline and the hydrogen discharge valve, avoids pipeline blockage and valve body freezing caused by low-temperature solidification of gas and liquid water, and significantly improves hydrogen discharge The opening speed of the system also shortens the cold start-up time of the fuel cell system at low temperatures, improves the efficiency of the fuel cell system, and the overall design is simple and easy to implement.

Summary of the invention

In order to solve the problems existing in the prior art, the present invention provides a current-based method for controlling the opening frequency of a hydrogen discharge valve and a discharge valve. The hydrogen discharge frequency is adjusted according to different efficiencies. The discharge frequency is high in the high-efficiency zone and low in the low-efficiency zone. . The efficiency of a fuel cell is determined by the current. The greater the current, the lower the efficiency. Therefore, when supplying hydrogen, the amount of hydrogen supplied can be controlled according to the efficiency of the battery under different currents, as well as the control of the hydrogen circulation loop.

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

An electric current-based method for controlling the opening frequency of a drain valve and a drain valve controls the opening period and opening time of the drain valve and the drain valve according to different current intervals, thereby improving the utilization rate of hydrogen. Among them, the opening period of the hydrogen exhaust valve is different at different intervals of the current; the opening time of the hydrogen exhaust valve is different at different intervals of the current; the opening period of the drain valve is the same at different current intervals; the opening time of the drain valve is different at different currents The interval, the opening time is different.

Further, the opening period of the hydrogen exhaust valve is different in different current intervals; when the opening period is 0～1/4I, the opening period is T1, when the opening period is between 1/4I and 1/2I, the opening period is T2, which is at 1/ At 2I to 3/4I, the turn-on period is T3, and at 3/4I to I, the turn-on period is T4;

Among them, T1>T2>T3>T4.

Furthermore, the opening time of the hydrogen exhaust valve is different in the interval of the current. At 0～1/4I, the opening time is t1, at 1/4I～1/2I, the opening time is t2, and at 1/2I～3/4I, the opening time is t3, at 3 When /4I amount ~ I amount, the opening time is t4;

Among them, T1>T2>T3>T4>t1>t2>t3>t4.

Further, the opening period of the drain valve is the same in different sections of the current, and both are T0.

Furthermore, the opening time of the drain valve is different in the interval of the current. At 0～1/4I, the opening time is t5, at 1/4I～1/2I, the opening time is t6, and at 1/2I～3/4I, the opening time is t7, at 3 When /4I amount ~ I amount, the opening time is t8;

Among them, T0>t8>t7>t6>t5.

The present invention provides a current-based method for controlling the opening frequency of a hydrogen discharge valve and a discharge valve, which adjusts the hydrogen discharge frequency according to different efficiencies, and has a high hydrogen discharge frequency in a high-efficiency interval and a low hydrogen discharge frequency in a low-efficiency interval.

Description of the drawings

In order to explain the technical solutions in the embodiments of the present invention more clearly, the following will briefly introduce the drawings used in the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative work, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings.

Figure 1 is a schematic diagram of the relationship between fuel cell efficiency and current;

Figure 2 is a schematic diagram of a fuel cell anode drainage hydrogen exhaust system;

Figure 3 shows the change curve of fuel cell hydrogen discharge cycle and open time with current;

Figure 4 is a curve of the opening frequency and opening time of the fuel cell drain valve as a function of current;

Figure 5 shows an example of how the opening frequency and opening time of the fuel cell hydrogen exhaust valve vary with current;

Figure 6 shows an example of how the opening frequency and opening time of the fuel cell drain valve vary with current.

detailed description

The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for ease of description, the drawings only show a part but not all of the structure related to the present invention.

An electric current-based method for controlling the opening frequency of a drain valve and a drain valve controls the opening period and opening time of the drain valve and the drain valve according to different current intervals, thereby improving the utilization rate of hydrogen. Among them, the opening period of the hydrogen exhaust valve is different at different intervals of the current; the opening time of the hydrogen exhaust valve is different at different intervals of the current; the opening period of the drain valve is the same at different intervals of the current; the opening time of the drain valve is different at different currents The interval, the opening time is different.

Further, the opening time of the hydrogen exhaust valve is different in the interval of the current. At 0～1/4I, the opening time is t1, at 1/4I～1/2I, the opening time is t2, and at 1/2I～3/4I, the opening time is t3, at 3 When /4I amount ~ I amount, the opening time is t4;

Among them: T1>T2>T3>T4>t1>t2>t3>t4.

Further, the opening period of the drain valve is the same in different sections of the current, and both are T0;

Further, the opening time of the drain valve is different in the interval of the current. At 0～1/4I, the opening time is t5, at 1/4I～1/2I, the opening time is t6, and at 1/2I～3/4I, the opening time is t7, at 3 When /4I amount ~ I amount, the opening time is t8;

Among them, T0>t8>t7>t6>t5.

Example

The opening period of the hydrogen exhaust valve is different in different areas of the current; when it is 0～1/4I, the opening period is 20s, when it is 1/4I～1/2I, the opening period is 17.5s, and it is at 1/2I. At ~3/4I rating, the turn-on period is 15s, and at 3/4I ~ I rating, the turn-on period is 12.5s;

In different ranges of current, the turn-on time is different. At 0～1/4I, the opening time is 4s, at 1/4I～1/2I, the opening time is 3s, at 1/2I～3/4I, the opening time is 2s, at 3 When /4I amount ~ I amount, the opening time is 1s;

The opening period of the drain valve is the same in different areas of current, both are 20s;

The opening time of the drain valve is different in the interval of the current. At 0～1/4I, the opening time is 1s, at 1/4I～1/2I, the opening time is 2s, at 1/2I～3/4I, the opening time is 3s, at 3 When /4I~I, the opening time is 4s.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. And variations, the scope of the present invention is defined by the appended claims and their equivalents.

Claims

A current-based method for controlling the opening frequency of a drain valve and a drain valve is characterized in that the opening period and opening time of the drain valve and the drain valve are respectively controlled according to different current intervals:

The opening period of the hydrogen exhaust valve is different in different areas of the current;

The opening time of the hydrogen exhaust valve is different in the range of current;

The opening period of the drain valve is the same in different sections of current;

The opening time of the drain valve is different in the interval of the current.
A current-based method for controlling the opening frequency of a hydrogen discharge valve and a discharge valve according to claim 1, wherein the opening period of the hydrogen discharge valve is different in different current intervals, and specifically:

At 0～1/4I rating, the opening period is T1; at 1/4I rating to 1/2I rating, the opening period is T2; at 1/2I rating to 3/4I rating, the opening period is T3; at 3 At /4I to I, the turn-on period is T4; among them, T1>T2>T3>T4.
The method for controlling the opening frequency of a hydrogen discharge valve and a discharge valve based on current according to claim 2, wherein the opening time of the hydrogen discharge valve is different in different current intervals, and specifically:

At 0～1/4I, the opening time is t1; at 1/4I～1/2I, the opening time is t2; at 1/2I～3/4I, the opening time is t3; at 3 /4I~I, the opening time is t4; among them, T1>T2>T3>T4>t1>t2>t3>t4.
The method for controlling the opening frequency of a hydrogen discharge valve and a drain valve based on current according to claim 1, wherein the opening period of the drain valve is the same in different current intervals, and both are T0.
A current-based method for controlling the opening frequency of a hydrogen discharge valve and a drain valve according to claim 4, wherein the opening time of the drain valve is different in different current intervals, specifically:

At 0～1/4I, the opening time is t5; at 1/4I～1/2I, the opening time is t6; at 1/2I～3/4I, the opening time is t7; at 3 /4I~I, the opening time is t8; among them, T0>t8>t7>t6>t5.