JP2946783B2 - Fuel cell equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell system.

[0002]

2. Description of the Related Art In a facility using a fuel cell, unless the pressure in a container storing the fuel cell is maintained at a constant pressure, there is a possibility that the electrolyte of the fuel cell leaks into the container.
Therefore, in order to prevent leakage of the electrolyte, an inert gas such as N ₂ gas has been supplied into the container, and pressure control has been performed so as to keep the pressure in the container constant.

An example of a fuel cell system for performing such pressure control is shown in FIG. 6. In FIG. 6, a is a container in which a fuel cell b is stored, and c is connected near the top of the container a and is not shown. Inert gas G sent from the inert gas supply source
Gas is supplied to the container a, d is a shutoff valve installed in the middle of the inert gas supply tube c, and e is connected near the top of the container a and discharges the inert gas in the container a to the outside. An inert gas discharge pipe, f is a pressure control valve connected to a middle part of the inert gas discharge pipe e,
g is a pressure detector connected to the top of the container a for detecting the pressure in the container a, and h is a valve opening / closing command signal to the pressure control valve f based on the pressure signal i transmitted from the pressure detector g. It is a pressure control device that outputs j.

When the pressure of the container a is controlled in the above-described fuel cell system, the shut-off valve d is fully opened, and the inert gas G is supplied from the inert gas supply source (not shown) into the container a via the inert gas supply pipe c. I do.

Further, the container a detected by the pressure detector g
Is supplied to the pressure control device h as a pressure signal i, and is compared with a set pressure signal previously set in the pressure control device h.

When the pressure in the vessel a is lower than the predetermined pressure, the valve opening / closing command signal j from the pressure control device h
As a result, the pressure control valve f is closed, and the pressure in the container a rises to a predetermined pressure and is maintained at the predetermined pressure.

When the pressure in the container a is higher than a predetermined pressure, the pressure control valve f is opened in response to the valve opening / closing command signal j from the pressure control device h, and the inert gas in the container a is changed to the inert gas. By discharging to the outside through the discharge pipe e, the pressure in the container a decreases and is maintained at a predetermined pressure.

[0008]

However, in the above-described fuel cell system, since the on-off valve d provided in the inert gas supply pipe c is always fully opened, the pressure control valve f is opened and the inside of the container is opened. When the inert gas is discharged,
The inert gas G must be supplied from the inert gas supply pipe c to the container a.
Since it is introduced into the inside and flows out from the container a to the inert gas discharge pipe e, there is a problem that the consumption of the inert gas increases.

The present invention has been made in view of the above circumstances, and has as its object to provide a fuel cell system that consumes a small amount of inert gas.

[0010]

SUMMARY OF THE INVENTION The present invention provides a container in which a fuel cell is housed, an inert gas supply pipe connected to the container and provided with a shut-off valve in the middle, and a fuel cell connected to the container and provided in the middle. An inert gas discharge pipe equipped with a pressure control valve in the section, a pressure detector connected to the container and detecting the pressure in the container, and when the pressure detected by the pressure detector is equal to or lower than a predetermined lower limit set pressure. In the case of a predetermined pressure higher than the lower limit set pressure by fully opening the shutoff valve, a valve opening / closing command for fully closing the shutoff valve is given to the shutoff valve, and the pressure detected by the pressure detector is set to a predetermined upper limit. A pressure control device that opens the pressure control valve when the pressure is equal to or higher than the set pressure and provides a valve opening / closing command to the pressure control valve to throttle the pressure control valve when the predetermined pressure is lower than the upper limit set pressure. is there.

[0011]

When the pressure in the container detected by the pressure detector is lower than the lower limit set pressure, the shut-off valve is fully opened while the pressure control valve is fully closed, and inert gas is supplied from the inert gas supply source into the container. When the pressure in the container reaches a predetermined pressure higher than the lower limit set pressure, the shutoff valve is closed.

When the pressure in the container detected by the pressure detector is equal to or higher than the upper limit set pressure, the pressure control valve is opened with the shut-off valve fully closed, and the inert gas in the container passes through the inert gas discharge pipe to the outside. When the pressure is discharged and the pressure in the container reaches a predetermined pressure lower than the upper limit set pressure, the pressure control valve is throttled and fully closed.

As described above, the shut-off valve is opened only when the pressure in the container is equal to or lower than the lower limit set pressure. In other cases, the shut-off valve is fully closed. In addition, the inert gas on the upstream side of the shut-off valve does not flow out of the container to the inert gas discharge pipe, so that the consumption of the inert gas is reduced.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show an embodiment of a fuel cell system according to the present invention. In FIG. 1, reference numeral 1 denotes a container in which a fuel cell 2 is stored, and 3 denotes an inert gas (not shown) connected near the top of the container 1. An inert gas supply pipe for supplying the inert gas G supplied from the supply source to the container 1, a shut-off valve 4 provided in the middle of the inert gas supply pipe 3, and a container 1
, An inert gas discharge pipe for discharging the inert gas in the container 1 to the outside, a pressure control valve 6 connected to a middle part of the inert gas discharge pipe 5, a 7 connected to a top of the container 1, and A pressure detector 8 for detecting the pressure in the container 1 is provided with a valve opening / closing command signal (valve opening / closing signal) to the shutoff valve 4 and the pressure control valve 6 based on the pressure signal (pressure) A transmitted from the pressure detector 7. Command) It is a pressure control device that outputs V ₁ and V ₂ .

The pressure control device 8 shown in FIG. 1 is provided with devices as shown in FIG. 2, and 9 in FIG.
1,10-2,10-3 intermediate set pressure signal to the lower limit set pressure signal (limit set pressure) A ₁ in order to fully open the shutoff valve 4, the shutoff valve 4 fully closed (predetermined pressure)
A ₂ , a pressure signal setting device for setting an upper limit set pressure signal (upper limit set pressure) A ₃ for opening the pressure control valve 6 to the signal comparator 9, wherein the signal comparator 9 includes a pressure detector 7 and the pressure signal setting devices 10
-1,10-2,10-3 by comparing the set pressure signal A _1, A _2, A ₃ which is set in accordance with a result of comparison, also a valve closing command signal V ₁ to the shut-off valve 4 below switcher The switching command signal V ₃ can be given to each of the reference numerals 15.

Reference numeral 11 denotes a reference pressure signal setter for setting a reference set pressure signal _AO so as to open and close the pressure control valve 6. Reference numeral 12 denotes a pressure signal A detected by the pressure detector 7 and the reference pressure signal setter. A subtractor 13 for obtaining a deviation signal ΔA of the reference set pressure signal A _O set by the subtractor 11 is a subtractor 12.
Computing unit that performs a proportional-integral operation on a deviation signal ΔA from
Reference numeral 4 denotes a valve opening degree setting device for setting a 0% command signal V ₀ for setting the opening of the pressure control valve 6 to 0%, and 15 denotes a case where the switching command signal V ₃ from the signal comparator 9 is not given. The 0% command signal V ₀ from the valve opening degree setting device 14 is output as a valve opening / closing command signal V ₂ , and when the switching command signal V ₃ is given from the signal comparator 9, the PI Calculation signal V ₄
Which is a switching device to provide a valve closing command signal V ₂ to the pressure control valve 6.

As the reference pressure set pressure signal A _O , for example, a predetermined value larger than the lower limit set pressure signal A _{1 and} smaller than the intermediate set pressure signal A ₂ is selected.

Next, the operation of the present invention will be described with reference to FIGS.

When the pressure of the container 1 is controlled, the pressure in the container 1 detected by the pressure detector 7 is given as a pressure signal A to the signal comparator 9 and the subtractor 12 of the pressure control device 8, and the signal comparison is performed. In the unit 9, the pressure signal setting units 10-1, 1
The magnitudes of the detected lower limit pressure signal A ₁ , intermediate set pressure signal A ₂ , upper limit set pressure signal A ₃ and the detected pressure signal A are compared with each other according to 0-2 and 10-3.
Then, a deviation signal ΔA (= A _O −A) between the reference pressure signal A _O preset by the reference pressure signal setting device 11 and the detected pressure signal A is obtained.

When the detected pressure signal A is higher than the lower limit pressure signal A ₁ and lower than the intermediate set pressure signal A ₂ as before time t _{1 in} FIG. the pressure is maintained at a predetermined pressure, shut-off valve 4 by the valve command signal V ₁ of the from the signal comparator 9 has become fully closed as before time t ₁ in FIG. 4, and signal comparator Changer 1 from 9
5 is not supplied with the valve opening / closing command signal V ₃ , the switching device 15 outputs 0% set by the valve opening degree setting device 14.
The command signal V ₀ is the pressure control valve 6 as the valve opening / closing command signal V _2.
Given, the pressure control valve 6 is in the fully closed as before time t ₁ in FIG.

When the detected pressure signal A is lower than the lower limit set pressure signal A ₁ as shown in a portion after the time t _{1 in} FIG. 3, the pressure in the container 1 falls below a predetermined pressure. and for that, the shut-off valve 4 by a valve switching command signal V ₁ of the from the signal comparator 9 is opened at the time of past time t ₁ as shown in FIG. 4, is fully opened. Therefore, the inert gas G from the inert gas supply source not shown is supplied into the container 1 through the inert gas supply pipe 3, the pressure in the container 1 is recovered, the pressure signal A is than the lower limit set pressure signal A ₁ Will also be higher.

When the pressure in the container 1 rises and the pressure signal A reaches a predetermined intermediate set pressure signal A ₂ at time t ₂ , as shown in FIG. shut-off valve 4 by the valve command signal V ₁ of the 9 is closed as in the time t ₂ in FIG. 4, the fully closed.

Since the switching command signal V ₃ is not output from the signal comparator 9 from the time t ₁ to t ₂ , the 0% command signal from the switching device 15 is sent to the pressure control valve 6. V ₀ is output as the valve opening / closing command signal V ₂ , and the pressure control valve 6 is closed as shown from time t ₁ to t ₂ in FIG.

The pressure in the container 1 increases, and the time t _{3 in} FIG.
As shown in later, if the upper limit set pressure signal A ₃ to detected pressure signal A is predetermined, the switching signal V ₃ from the signal comparator 9 is given to the switching unit 15, switching unit 15 PI
Switching is performed so as to output a signal from the arithmetic unit 13. For this reason, the PI computing unit 13 performs a proportional-integral operation on the deviation signal ΔA between the pressure signal A obtained by the subtractor 12 and the reference pressure setting signal A _O , and outputs the obtained PI operation signal V ₄ to the switching unit 1.
5 is given to the pressure control valve 6 as through valve switching command signal V ₂ to the predetermined opening degree corresponding to the magnitude of the pressure control valve 6 is a valve closing command signal V _2, as shown in time t ₃ after the 5 Opened to. Therefore, the inert gas in the container 1 is discharged from the inert gas discharge pipe 5 to the outside, and the pressure in the container 1 decreases to a predetermined pressure.

When the pressure in the container 1 decreases, the PI operation signal V ₄ from the PI operation unit 13 and hence the valve opening / closing command signal V ₂ given to the pressure control valve 6 decrease, and the opening degree of the pressure control valve 6 decreases. Is gradually squeezed, and the detected pressure signal A is
And time descend to the reference set pressure signal A ₀ as in t _4, the pressure control valve 6 is fully closed as shown in the time t ₄ in FIG. As shown in FIG. 5, the operation of opening and closing the pressure control valve 6 based on the proportional-integral operation value without turning it on and off prevents sudden pressure fluctuations in the container 1 and quickly reduces the pressure in the container 1. This is for stabilization.

It should be noted, between t ₄ from the time t ₂ too, as shown in FIG. 4, shutoff valve 4 is fully closed. When the pressure control valve is fully closed, the signal comparator 9 outputs a switching command signal V _3.
The switch 15 is switched to the valve opening degree setting device 14 in order to prevent the output from being performed.

In this embodiment, the shut-off valve 4 connected to the inert gas supply pipe 3 is opened and the inert gas G is supplied to the container 1 only when the pressure in the container 1 falls below a predetermined pressure.
Otherwise, the shut-off valve 4 is fully closed otherwise, when the pressure control valve 6 is opened, the inert gas upstream of the shut-off valve 4 flows from the container 1 to the inert gas discharge pipe 5. There is no outflow and, therefore, no waste of inert gas and no consumption.

It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

[0030]

According to the fuel cell system of the present invention, the consumption of the inert gas can be reduced, and the excellent effect of being economical can be obtained.

[Brief description of the drawings]

FIG. 1 is a control system diagram of an embodiment of a fuel cell system according to the present invention.

FIG. 2 is a control system diagram of a pressure control device applied to the fuel cell equipment of the present invention.

FIG. 3 is a graph showing how a detected pressure signal changes.

FIG. 4 is a graph showing a state in which a shutoff valve opens and closes when a detected pressure signal changes as shown in FIG.

FIG. 5 is a graph showing a state where a pressure control valve opens and closes when a detected pressure signal changes as shown in FIG.

FIG. 6 is a control system diagram of an example of a conventional fuel cell facility.

[Explanation of symbols]

1 container 2 fuel cell 3 inert gas supply pipe 4 shutoff valve 5 inert gas discharge pipe 6 a pressure control valve 7 a pressure detector 8 the pressure control device V _1, V ₂ valve switching command signal (valve command) A pressure signal (pressure) A ₁ lower limit setting pressure signal (limit set pressure) a ₂ intermediate set pressure signal (predetermined pressure) a ₃ set upper limit pressure signal (the upper limit set pressure)

Claims (1)

(57) [Claims] 1. A container in which a fuel cell is stored, an inert gas supply pipe connected to the container and provided with a shut-off valve in the middle part, and a pressure control valve connected to the container and provided in the middle part. An inert gas discharge pipe, a pressure detector connected to the container for detecting the pressure in the container, and when the pressure detected by the pressure detector is equal to or lower than a predetermined lower limit set pressure, the shutoff valve is fully opened to set the lower limit. In the case of a predetermined pressure higher than the pressure, a valve opening and closing command to fully close the shutoff valve is given to the shutoff valve, and when the pressure detected by the pressure detector is equal to or higher than a predetermined upper limit set pressure, the A fuel cell system comprising: a pressure control device that opens a pressure control valve and, when the predetermined pressure is lower than an upper limit set pressure, gives a valve opening / closing command to throttle the pressure control valve to the pressure control valve.