JPS60130060A - Method of controlling gas pressure of fuel cell - Google Patents

Abstract

PURPOSE:To enable the pressures of a few gas systems to be simultaneously controlled with a well-maintained balance by controlling different reaction gases supplied to a fuel cell by means of pressure regulators in which a high pressure gas is used as a control fluid. CONSTITUTION:The pressures of a fuel gas, an oxidant and an inactive gas are controlled by means of pressure regulators 10a, 10b and 10c in which a high pressure gas is used as a control fluid. Each pressure regulator has an airtight control chamber 2a which is surrounded by a lower casing 2 and a diaphragm 3 and to which the pressure of an inactive gas such as a control fluid is applied. Therefore, by supplying a high pressure gas (used as a control fluid) the pressure of which is controlled by a single main pressure regulator 20 to the diaphragms 3 of the regulators 10a, 10b and 10c, it is possible to maintain a good balance between the pressures of a few gas systems including reaction gas systems of the fuel cell.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to fuel cells, and particularly to a gas pressure control method for a hydrogen-oxygen fuel cell.

[Prior art and its problems]

Conventionally, as a gas pressure control method for this type of fuel cell, there is a method in which a mechanical pressure controller is used and the gas pressure is adjusted by adjusting the screwing amount of a screw handle that contacts a diaphragm of the pressure controller.

FIG. 1 is a sectional view of a mechanical pressure regulator. 1st
In the figure, a diaphragm 3 is interposed between an upper casing 1 and a lower casing 2 to which an inlet pipe 1a and an outlet pipe 1b are attached, and a valve 5 having a spring 4 is connected to the diaphragm 3 in the upper casing l. A screw 8 for adjusting the force of the spring 7 is provided in the lower casing 2, and by screwing the screw 8, the force of the spring 7 and the spring 4 is adjusted to apply preload to the diaphragm 3, thereby preventing gas entering through the inlet pipe 1a. flows between the valve 5 and the seat 6, the pressure is reduced, the pressure is balanced with the pre-pressure, and the pressure is controlled, and the outlet pipe 1b is
It will be drained out.

However, in the gas pressure control method using a mechanical pressure regulator, the pressure is adjusted by screwing in a screw to control the fuel gas.

It is necessary to screw in the screws separately for each of the three types of gases: reactive gas such as oxidizing gas, and inert gas in the pressure vessel, and it is difficult to balance the pressures of these multiple gas systems at the same time. The disadvantage is that it is extremely difficult.

Particularly in recent years, the pressure of reactant gases has tended to increase in order to improve the characteristics of batteries, but in order to withstand such high pressures, mechanical pressure regulators must use stiff springs and thick diaphragms. The total dead zone and hysteresis of the pressure regulator due to the strength of the spring and diaphragm generally exists at 0.3% or more, and when using such a pressure regulator to control the pressure of two reaction gases, the differential pressure reaches as much as 0.5%. This is 500mm when the battery is operated at approximately 10klilf/cd.
This means that a pressure difference of Aq is generated.

Such a pressure difference causes gas blow-through in the matrix holding the electrolyte, which affects the characteristics of the battery.

This is undesirable not only from the viewpoint of safety, but also because it may lead to the formation of explosion gas.

[Purpose of the invention]

In view of the above, an object of the present invention is to provide a gas pressure control method for a fuel cell that can supply a pressure-balanced reaction gas.

[Summary of the Invention] According to the present invention, this object is achieved by collectively controlling different reaction gases supplied to a fuel cell by a pressure controller using a high-pressure gas as a control fluid.

[Embodiments of the invention]

The present invention will be described in detail below based on the drawings.

@2 Figure shows pressure regirator 1 that uses high pressure gas as the control fluid.
This shows a gas pressure control system for a fuel cell using 0a+1ob and 1Qc, and in this embodiment, the gas pressures of fuel gas, oxidizing gas, and inert gas are collectively controlled by a μ-cal regulator.

In the figure, reference numeral 11 is a fuel cell, which is housed in a pressure vessel 12. Although shown schematically in this figure, the fuel cell 11 includes a matrix lla, a fuel electrode 11b and an oxidizer electrode 11c arranged on both sides of the matrix lla, and a fuel manifold l for fuel gas supplied to and discharged from the fuel electrode 11b.
id and an oxidant manifold lie for supplying and discharging oxidizing gas to and from the oxidizing electrode 11c.

A fuel gas pipeline leading to the fuel electrode 11b includes an inlet pipe 13a connected to a supply valve 13b and a supply nozzle 13b.
A pressure regulator 10a provided downstream of the pressure regulator 10a.

and a conduit 1 located behind the pressure regirator 10a.
3c is connected to a fuel manifold 11d that supplies and discharges fuel gas, and a pipe line for the fuel gas to be discharged after being supplied to the fuel electrode is composed of a pipe line 13d, a throttle pulp 13e for flow rate adjustment, and an outlet pipe 13f. be done. The oxidant electrode 11c The pipe line for supplying the K oxidant gas is also composed of an inlet pipe 14a, a supply valve 14b, a pressure regulator 1ob, and a pipe line 14c, like the fuel gas, and is an oxidizer manifold lie for supplying and discharging the oxidant gas. The pipe connected to the oxidant electrode and discharged after being supplied to the oxidizer electrode is composed of a pipe 14d, a flow rate adjustment throttle valve 14e, and an outlet pipe 14f. The gas supply pipe for supplying inert gas into the pressure vessel is also composed of the inlet pipe 15 &, the supply valve 15b, the pressure regulator and the pipe 15c in the same way as the reaction gas supply pipe. A gas conduit connected to the pressure vessel 12 and discharged from the pressure vessel includes a conduit 15d, a flow rate adjustment throttle valve 15e, and an outlet pipe 15f.

On the other hand, the inert gas pipeline supplied to the control chambers of the pressure regulators 10a, 10b, 10c includes an inlet pipe 16a, a supply valve 16b, a main pressure regulator 20. The pipe line 9a and the pressure regirator 10 are divided into three sides at the end of the pipe line 9a.
It is composed of a pipe line 9 and a relief valve 9b leading to the respective control chambers of a+ 10b+ 10c. In addition, main pressure regulator 2
O can be a conventional mechanical pressure regirator.

Next, pressure control of fuel gas and oxidant gas as reaction gases supplied to the fuel cell and gas supplied into the pressure vessel will be described. Fuel gas is supplied through the supply valve 13b
When the fuel gas is opened, it enters from the inlet pipe 13a in the direction of the arrow, flows into the pressure regulator 0a, enters the fuel manifold lid that supplies and discharges fuel gas via the pipe 13c, and supplies fuel gas to the fuel electrode. After that, the fluid passes through the pipe line 13d, the flow rate is adjusted by applying fluid resistance in the squeeze pulp 13e, and is exhausted from the outlet pipe 13f in the direction of the arrow. On this occasion,
Supply valve 16b for inert gas line as control fluid
When opened, the cine active gas enters the inlet pipe 16a in the direction of the arrow, and the pressure of the control fluid is adjusted to a predetermined pressure while releasing a small amount of gas through the main pressure regulator 20 and the relief valve 9b. The pressure of the fuel gas is applied to the control chamber of the pressure regulator 10a via the lines 9a and 9, and the pressure of the fuel gas passing through the pressure regulator is controlled according to the adjusted value of this pressure, and the predetermined pressure for the operation of the fuel cell is set in the fuel manifold. Fuel gas is supplied.

In the same way, the oxidizing gas is supplied to the inlet pipe 14a and the pressure regulator 10 from the direction of the arrow by opening the supply pulp 14b.
b, the oxidizing gas enters the manifold via the pipe 14c, and after supplying the oxidizing gas to the oxidizing electrode, the pipe 14
d, fluid resistance is applied by the throttle pulp 14e to adjust the flow rate, and the oxidant gas is discharged in the direction of the arrow through the outlet pipe 14f, but the gas supplied to the oxidizer manifold is the same as the fuel gas. The pressure of the fuel gas is regulated by the main pressure regulator 20 to control the gas pressure for operating the fuel cell.

The gas in the pressure vessel is treated in the same way as the reaction gas described above.
When the supply pulp 15b is opened, inert gas flows from the direction of the arrow to the inlet pipe 15a and the pressure regulator 0C2 pipe 15c.
The gas enters the pressure vessel 12 via the pipe line 15d and the squeeze pulp 15e to adjust the flow rate, and is discharged via the outlet pipe 15f. Similarly, the same pressure of the control fluid from the main pressure regulator 20 is applied to the control chamber of the pressure regulator 10c, and the gas supplied into the pressure vessel is controlled to the pressure for fuel cell operation. Note that, since the internal fluid resistance of the fuel cell and the pressure vessel is small, the throttle valves of each gas system are sufficiently throttled to provide fluid resistance and obtain a predetermined pressure for operating the fuel cell.

In this way, according to the above embodiment, in order to maintain the pressure of each system of the fuel cell at a predetermined pressure, the high pressure gas whose pressure has been regulated by the single main pressure regulator is used as the control fluid for each of the pressure regulators. By adding it to the diaphragm,
This is effective if the pressures of multiple gas systems containing the reactant gases of the fuel cell are controlled simultaneously and in a mutually balanced manner.

Additionally, by using a high-pressure inert gas as the pressure regulator's control fluid, the springs of traditional mechanical pressure regulators are no longer needed and a thin diaphragm can be used, reducing the pressure regulator's dead band and hysteresis. However, the differential pressure of the gas can be reduced.

Furthermore, since an inert gas is used as the control fluid in this embodiment, there is no risk of explosion even if the diaphragm were to break and the reaction gas and control fluid were to mix.

Next, the structure of a pressure controller using gas as a control fluid used in the present invention will be explained based on the drawings.

Fig. 3 1' is an improved version of the conventional pressure regulator explained in Fig. 1. Items with the same structure as Fig. 1 are given the same reference numerals, but there are differences from Fig. 1. is a section surrounded by the lower casing 2 and the diaphragm 3,
An airtight control chamber 2a is provided to which pressure of, for example, inert gas is applied as a control fluid. The lower casing 2 is provided with a pipe line 9 that passes through it, and the screw 8 passes through the lower casing 2 and slides with the lower casing 2.
A ring packing 10 is inserted to maintain airtightness. This screw 8 can be used for fine adjustment of pressure.

Furthermore, in the present invention, since high-pressure gas is used as the control fluid supplied to the control chamber 2a, each chamber of the upper casing 1 and the lower casing 2 has approximately the same pressure, and therefore the diaphragm 3 needs to be thinner than before. I can do it.

@ Figures 4 and 5 show other embodiments of the pressure regulator, respectively. Figure 4 is what can be called a twin-barrel pressure regulator, and the pressure regulator shown in Figure 3 is By combining two units, the control chamber 21 and the control gas piping 22 are combined into one, thereby eliminating the pressure difference between the control gases.

Fig. 5 shows a measure to be taken when the diaphragm 72m 3 is damaged.The control gas is not brought into direct contact with the diaphragm 72m, but acts through an inert fluid 23. A fluid separator 24 having a bellows structure is provided as a means for separating and transmitting pressure between the fluid 23 and the control gas.

〔Effect of the invention〕

As is clear from the above theory Qjl, according to the present invention, different reaction gases supplied to the fuel cell are collectively controlled by a pressure controller using high-pressure gas as the control fluid, thereby controlling the pressure of multiple gas systems. can be controlled simultaneously and in balance with each other.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a pressure controller according to the prior art, FIG. 2 is a system diagram showing one embodiment of the present invention, and FIGS. 3 to 5 show different embodiments of the pressure controller used in the present invention. FIG. 10, 10a, 10b, 10c ・=pressure controller,
11-... Fuel cell, 20... Main pressure regulator. Figure 1 Figure 3 Figure 2 Figure 4 Figure 5

Claims (1)

[Claims] The different reactant gases supplied to the fuel cell are