JPS59149667A - Fuel battery - Google Patents

Abstract

PURPOSE:To attain stabilized battery performance and long life by adjusting the amount of steam to be supplied to a fuel battery body and by controlling an internal resistance value. CONSTITUTION:During operation of fuel battery body 1, a controller 14b having received a measuring value signal of an electromotive force measuring apparatus 11 controls the fuel gas and oxidizing agent gas supply regulator valves 4, 5 and regulates the flow of supply in accordance with the specified operation program. The controller 14b having received measured value signals from the internal pressure measuring apparatus 9, internal temperature measuring apparatus 10 and internal resistance measuring apparatus 12 compares the volume of said gas with given volume of phosphoric acid and controls the internal resistance in the specified range by controlling independently the steam supply valves 15, 16. Fluctuation of the volume of phosphoric acid can be controlled with in the specified range and the battery performance and reliability can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fuel cell, and particularly to a fuel cell with improved life characteristics.

[Technical background of the invention and important points]

A fuel cell is a device that converts the chemical energy of fuel into electrical energy. A fuel cell normally has a pair of porous electrodes sandwiching a sulfuric acid layer, and a gaseous fuel such as hydrogen is brought into contact with the back surface of one electrode, and 111! is placed on the back surface of the other electrode. Contact with an oxidizing agent such as
The electrical energy generated by the chemical reaction of the gas that occurs at this time is extracted from the pair of electrodes.

Examples of the electrolyte include molten carbonate, alkaline solution, and acidic bath solution, but the principle of a typical fuel cell using phosphoric acid as the electrolyte will be explained.

In FIG. 1, the electrolytic layer 1 matrix is formed by soaking a fibrous sheet or ore modified powder with phosphoric acid. 2 is an anode, and 3 is a cathode, which is a carbonaceous porous electrode, and a 11:1 platinum catalyst is coated on the surface in contact with the electrolyte 1-1. 4 is a space through which a gas containing hydrogen flows, and 5 is a space through which an oxidizing agent gas, preferably air, flows. Hydrogen flowing into the space 4 diffuses into the pores of the porous electrode 2 and reaches the catalyst. In this case, hydrogen scum is converted into hydrogen ions and electrons by the action of a catalyst.
do. Reaction formula ld, If2-→21-1 + 2e
It is.

Hydrogen ions immediately enter the solute layer 1 and migrate toward the cathode due to the interlayer action. On the other hand, hydrogen ions are separated by separation of the hydrogen gas.
Saito puts vit into Anno 1 and 2. At the cathode,
Hydrogen ions migrated from the oxidizing agent (/C, picked up) 11, acid adsorbent diffused through the pores of the cathode 3, and an external load was removed from the anode 2. , the turtle is working L'+5: Returning to the quasi cathode 3, the three parties with the electrons cause a deficiency reaction on the catalyst surface.

Thus, a reaction occurs in which hydrogen is oxidized to water, and a reaction in which the chemical energy of hydrogen provides electrical energy under external load.

At this time, part of the electrical energy is inside the electrolyte layer 1,
It is consumed by the internal resistance of the battery. Therefore, in order to increase battery efficiency, the electrolyte layer is designed to be extremely thin to shorten the migration distance of hydrogen ions and reduce resistance.

Furthermore, hydrogen gas supplied as fuel and air as oxidant gas are usually pressurized to several atmospheres. This is because, like in general chemical reactions, increasing the concentration of substances involved in the reaction is an effective means of increasing the reaction rate.

When actually supplying each gas to the main body of the hidden pond, direct contact or mixing of hydrogen and oxygen must be prevented.

As shown in FIG. 1, only the electrolyte layer 1 substantially separates the fuel gas and the oxidant gas. Electrolyte JWi
As mentioned above, 1 is a fibrous sheet or mineral powder impregnated with phosphoric acid, and its thickness is extremely thin, about 0.1 mm, and the interfacial tension of the phosphoric acid prevents the two gases from mixing. There is.

Therefore, to operate the fuel cell safely, both gases must be supplied at very equal pressures. That is, even when the supply gas flow fluctuates due to load fluctuations and when starting and stopping, the differential pressure between the two gases must be controlled to an extremely small difference of several tens of millimeters or less in the water column.

On the other hand, in order to operate a combustion engine battery safely and with stable performance, it is important to maintain a constant capacity of the electrolyte, i.e., phosphoric acid, in the thin electrolyte layer. ,ru.

In other words, when phosphoric acid 4 g-l decreases during operation,
Thin ma) IJ lux vacancies are generated due to a number of occurrences, and the contact interface between the catalyst, which is the reaction site, and the reaction gas decreases.Consequently, the contact resistance (internal resistance) increases. Even if the differential pressure between the fuel gas and the oxidant gas is small, mixing of the two gases will occur, resulting in ineffective consumption of gas (reduction in generation efficiency).Furthermore, abnormal heat generation will cause damage to the fuel cell itself. Problems such as damage and explosion may occur.

On the other hand, when the phosphoric acid capacity increases and the electrode's reservoir function (the electrode absorbs excess phosphoric acid without impairing its function) and the electrolyte decreases, the phosphoric acid stored in A function that can replenish the electrolyte layer.
Conventionally, the ratio is about 15 mm), the catalyst on the electrode is soaked in the phosphoric acid, and the reaction gas is prevented from directly diffusing.

This causes an extreme drop in battery performance and a sharp increase in the amount of atomized residue emitted into exhaust gas. It has been experimentally confirmed that when the electrolyte volume change due to this discharge exceeds a certain level, it does not return to normal. Therefore, it is necessary to control the electrolyte volume change within a certain amount from the beginning.

The phenomenon in which the capacity of phosphoric acid, which is an electrolyte, changes is greatly influenced by the operating temperature, operating pressure, and load of the fuel cell main body. However, it is possible to understand the fluctuation in phosphoric acid capacity by measuring the internal resistance based on the above-mentioned relationship.

Hereinafter, the phenomenon in which the container of phosphoric acid, which is an electrolyte, changes will be further explained.

That is, it is a reaction product of water and phosphorus pentoxide as shown in the following reaction formula of phosphoric acid V, which is an electrolyte, and has strong hygroscopicity. For this reason, under warm and dry conditions, 3 bows 0 + 1/2P,
O□. In 2H3PO4, the reaction d proceeds to the left, and under conditions of low temperature and high humidity, the reaction proceeds to the right.

On the other hand, when a load is applied, water is produced as an electrical reaction product. Furthermore, since the humidity which causes fluctuations in the phosphoric acid capacity is determined by the ratio of water vapor partial pressure to total pressure, it is affected by the operating pressure.

In this way, the '81 price change of Rin n cheap! tlijl the auxiliary phenomenon
1 ill requires consideration of many conditions, and conventional fuel cells do not have a function to reliably control the phenomenon of phosphoric acid capacity change in consideration of these conditions.

[Purpose of the invention]

The present invention was made in consideration of the above circumstances, and aims to stabilize battery performance by controlling the internal resistance value.

The purpose of the present invention is to provide a fuel cell that has a long service life.

[Summary of the invention]

In order to achieve the object of the present invention, the present invention provides: a fuel cell main body to which a fuel gas and oxidant gas supply/discharge system is connected; An operating temperature measuring device, a load device/electromotive force measuring device and an internal resistance measuring device connected to the main body of the fuel cell 11i2, a device for supplying water vapor to the fuel cell main body, and a device that adjusts the supply amount of the water vapor and controls the fuel cell 11i2. , 1' is characterized in that it is equipped with a lifting device having a function of controlling the internal resistance of the passage body.

['-(male side) of the invention]

An embodiment of the present invention will be described with reference to FIG.

The fuel gas and oxidant gas supply and discharge systems are provided in the fuel L4L pond body 1 via the distribution system (2). This supply/discharge system includes a supply section including respective supply flow rate measuring instruments 2, 3 and supply regulating valves 4, 5, and respective discharging sections linked with a differential pressure measuring instrument 6 for measuring the pressure of fuel gas and oxidant gas. It consists of a discharge section equipped with regulating valves 7 and 8. Furthermore, this fuel t, internal pressure 6 + IJ constant device 9, internal ζ, l! power measuring device [0, electromotive force (1'! 11. The control device 14 has the following ear configuration.
Internal temperature measuring device 11 9, internal temperature measuring device 101
and the internal resistance Ii'llll determination device (2) to manually input the measured value signal from (2) the steam supply device (not shown) and the steam supply connected to the piping of the above-mentioned supply section *15, ]L
5 is controlled by IIJ, fljiJ control is 1.42, and the electromotive force is 1.
Input the τ, 11 fixed value signal from the river control device 11 and control the supply regulating valves 4 and 5 by 1 iUU? 41 units] and 31].

According to 47I\Relative (described in 47I\Relative), when the fuel '1 is in operation of the pond body, the (11) fixed value signal of 1IIll constant device 11 (11iJ marked ('SudakikiernejTai 141)) is outputted at the specified level. According to the calculation program fj, each IJ (hk'i adjustment valve 4°5 is set to 1
tifl fli(] L, supply $1: Dir, adjust k. 7i? and valley seven law setting device 9, 10, 12
In response to the short measurement message from @ 7゛辷１ト１] Controller 14 a calculates the ratio with the existing phosphoric acid capacity, and calculates the water vapor supply volume I ↓ 5
, 16 independently 1llll L, internal resistance (cross θ
1) Control the IL resistance (IL resistance) within a predetermined range. Power,
This allows Rinkyoyosha's ':4' to be placed on the side of the cylindrical blade in a predetermined manner, thereby maintaining battery performance and reliability.

FIG. 3 shows a performance comparison diagram of a fuel cell according to a conventional example and an embodiment of the present invention.

In addition, the experimental example uses 103% phosphoric acid as the electrolyte,
Operating at 205°Cr 3.5 Ky/αd, the air utilization rate and fuel utilization rate are each 60% relative to the rated current value,
The results are compared when gas is supplied at 80%, water vapor is injected at 3% on the air side (equilibrium partial pressure is 2H), and 10% on the fuel side.

It can be clearly seen that the internal resistance value of the present invention example is maintained at a predetermined value, whereas the internal resistance value of the present invention example gradually increases. This is nothing but an effect of the present invention, which reliably controls the fluctuation phenomenon of phosphoric acid capacity.

Note that the water vapor can also be supplied from the temperature control device of the fuel cell.

〔Effect of the invention〕

As explained above, according to the present invention, the internal resistance and state values of the pond are monitored, water vapor is injected, and the system is started.

It is possible to control the internal resistance even when the engine is stopped, thereby controlling the fluctuation in the capacity of the electrolyte phosphoric acid,
It is possible to provide a fuel cell with stable performance and good life characteristics.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the operating principle of a fuel cell, FIG. 2 is a configuration diagram of a fuel cell according to an embodiment of the invention, and FIG. 31 is a performance comparison diagram of the conventional example and the example of the invention. l... Fuel cell main body 2, 3... Supply flow rate measuring device 4.5... Supply adjustment valve 6... Differential pressure 1llll
J regulator 7.8...Discharge regulating valve 9...Internal pressure measuring device 10...Internal temperature 41 regulating device 11...
Electromotive force measuring device 12...Internal resistance n+++ constant device [
3... Load device 14... Control device 14a
, 14b...controller 1.5. J6...Steam supply P Agent Patent attorney Kensuke Norichika (and 1 other person) Figure 1/72102 Figure 2 Figure 3 J Chioma 1-h) Procedural amendment (voluntary) 1. Indication of the case Japanese Patent Application No. 58-21569 2 Name of the invention Fuel cell 3 Person making the amendment Relationship to the case Patent applicant (307) Toureshibaura Electric Co., Ltd. 4 Agent 1 Uchisaiwai-cho, Chiyoda-ku, Toureto 100 -1-6 Corrected.

Claims (1)

[Scope of Claims] 1. A fuel cell main body to which a fuel gas and oxidant gas supply/exhaust system is connected, an operating pressure measuring device and an operating temperature measuring device connected to the fuel cell main body, and a fuel cell main body connected to the fuel cell main body. A connected load device/electromotive force 1111] constant device and internal resistance measuring device, a device for supplying water vapor to the fuel cell body, and controlling the internal resistance of the fuel cell body by adjusting the supply and back of the water vapor. A fuel cell comprising a 4G controller and a control device having seven functions. 2. The supply and discharge system includes a supply section equipped with a supply flow rate measuring device and a supply regulating valve, and a discharge section equipped with a discharge regulating valve that works with a differential pressure measuring device that determines the pressure difference between the fuel gas and oxidizer scum by 4i. A fuel cell according to claim 1, comprising: 3. The control device includes a first controller that controls the supply regulating valve mlJ based on the measured value signal of the electromotive force measuring device, and a water vapor control device that controls the supply regulating valve mlJ based on the measured value signal of the electromotive force measuring device, and the water vapor from the measured value signals of the operating pressure measuring device, the operating temperature measuring device, and the internal resistance measuring device. 3. The fuel cell according to claim 2, further comprising a second controller for controlling the supply amount of.