JPS5822865B2 - fuel cell power supply - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel cell power supply device equipped with an operation control device that improves the fuel utilization rate of a fuel cell.

In particular, the fuel cell power supply device according to the present invention includes a switching circuit for switching between no-load and load states, a fuel cell delay circuit for controlling the startup of the fuel cell when switching from no-load to load, and a fuel cell delay circuit for controlling the start-up of the fuel cell when switching from no-load to load. Equipped with an operation control device consisting of an intermittent drive circuit that operates the electrolyte supply device at appropriate cycles within a range that does not deteriorate the performance of the fuel cell and supplies an appropriate fuel mixed electrolyte, and a constant voltage circuit and a fuel concentration control circuit. This device is configured with a fuel supply device, a secondary battery, an electrolyte supply device, etc.

FIG. 1 shows a circuit configuration of a conventional fuel cell power supply device, particularly a liquid fuel cell power supply device that generates power by circulating an electrolyte mixed with fuel at a constant ratio to a fuel cell.

The fuel cell 10 plus a is connected to the input terminal of the constant voltage circuit 2, and the positive output/terminal C of this circuit 2 is connected to the fuel concentration control circuit 6.
The positive terminals of the fuel supply device 7, the electrolyte supply device 5, the secondary battery, for example, the storage battery 4, and the opening/closing contact e of the switching circuit 8.

It is connected to the positive terminal of the load device 3 via.

The output of the fuel concentration control circuit 6 is connected to a refueling device 7 to control the operation of this device.

The negative terminals of the 2, 3.4° and 5.6 cells are commonly connected to the negative terminal of the fuel cell 1.

The conventional fuel cell power supply device configured as described above continuously circulates and supplies an electrolytic solution mixed with a fuel concentration control circuit 6 at a constant fuel ratio to the fuel cell 1 using an electrolytic solution supplying device 5. The fuel cell 1 is caused to continuously generate electricity.

The generated fuel cell power is stabilized at a constant voltage by a constant voltage circuit 2 and supplied to a load device 3, as well as a fuel concentration control circuit 6.
, the fuel supply device 7 and the electrolyte supply device 5 are driven, and the storage battery 4 is floatingly charged.

The storage battery 4 is used as a starting power source or a peak load compensation power source.

The switching circuit 8 is driven by the storage battery 4 or other power source, and is activated by a switching signal depending on the application or usage conditions, and has an opening/closing contact e.

The load device 3 is turned on and off by the switch, and the load equipment 3 is switched on and off to switch between load and no-load states.

However, since such a conventional fuel cell power supply device uses a continuous power generation system, even if there is no load due to the operation of the switching circuit 8, the fuel cell 1 is operated by the constant voltage circuit 2 and the fuel concentration control circuit 6.
．． The drive current for the electrolyte supply device 5 and the floating charging current for the storage battery 4 are supplied to continue operation.

As shown in FIG. 4, the fuel utilization rate of the fuel cell 1 varies greatly depending on the fuel cell current density.

In other words, as the output current of the fuel cell 1 becomes smaller, the ratio of wasted fuel to the theoretically required amount of fuel increases, as shown in FIG. 5 (the part indicated by dots).

This is a fuel cell plate. This is due to catalytic decomposition of fuel at a fuel cell current density of 30 mA/d, 5 mA/Cr?
Compared to L, even though the current density is reduced to 1/6, the actual fuel requirement is reduced by only 1/2.

This increases the power generation cost and the power supply equipment is large.

This was a major cause of this.

(See Figure 2) One way to improve this is to stop the fuel cell power supply when there is no load and stop the supply of electrolyte mixed with fuel to the fuel cell 1. If the electrolyte supply stops, the battery performance will deteriorate significantly and the fuel utilization rate will drop significantly, and the fuel cell 1 will not be able to supply the specified power at the same time as the load equipment 3 starts operating. Problems such as the need for precise maintenance made it difficult to put it into practical use as an independent power source for other uses, a power source for lighthouses, a backup power source for communication equipment, etc. that require long-term maintenance-free operation.

As shown in Figure 3, no-load preliminary operation for Tb hours is required for the fuel/cell, and the capacity of the auxiliary battery increases.
This leads to drawbacks such as complicating the operation of the power supply device.

As explained above, there are problems with the conventional device.

The present invention solves the problems of the conventional devices, and provides a fuel cell power supply device that consumes less fuel and is easy to start up when starting the fuel cell operation.

Hereinafter, a circuit configuration of a fuel cell power supply device according to an embodiment of the present invention will be explained using FIG. 6.

Fuel cell 1, constant voltage circuit 2, load device 3, storage battery 4, fuel concentration control circuit 6, electrolyte supply device 5, fuel supply device 7
, the switching circuit 8 and its opening/closing contacts e.

,el. 12, e4 se5, e6 s, and the intermittent drive circuit 9 and its contact e3 constitute the fuel cell power supply device of the present invention.

The positive a of the fuel cell 1 is connected to the input terminal of the constant voltage circuit 2 via the switching contact e5, and the positive output C of this circuit 2 is connected to the fuel supply device 7, the power supply terminal of the switching circuit 8, and the storage battery 4 via the switching contact e6. is connected to the plus d of the

fuel concentration control circuit 6, electrolyte supply device 5, load equipment 3,
The power terminals of the intermittent drive circuit 9 and the intermittent drive circuit 9 each have a switching contact 11 .

14, go, and 12 are connected to the plus d of the storage battery 4.

The output of the fuel concentration control circuit 6 is connected to a fuel supply device 7 to drive and control this device.

The output contact e3 of the intermittent drive circuit 9 is the switching contact e4.
is provided in parallel with.

The negative terminals of the terminals 2, 3, 4, 5°6.8, and 9 are commonly connected to the negative b of the fuel cell 1.

The switching circuit 8 is operated by a switching signal depending on the application or usage conditions, and the output of this circuit 8 is an opening/closing contact e.

. 11 s 62 s e4 t g5 , e
6) Control.

The operation of the fuel cell power supply device configured as described above will be explained based on FIG. 7.

First, at time tl in FIG. 7E, the switching signal (FIG. 7A)
When the switching circuit 1 circuit 8 is switched from on to off, the opening/closing contact e becomes the output of this circuit 8.

"I!1'g4145 and e6 are switched from on to off as shown in FIG. The outputs of the voltage circuits 2 are turned off.

Conversely, the opening/closing contact e2 is switched from OFF to ON as shown in FIG. 7C, thereby activating the intermittent drive circuit 9.

At this time, the output of the intermittent drive circuit 9 changes from on to off as shown in Figure 7, and the contact e3 of this circuit 9 turns off.

In this state, the above 1.2, 3, 6, 7, 5. stops, and the switching circuit 8 and the intermittent drive circuit 9 are switched on by the storage battery 4.
Only one is in working condition.

Next, at time T2 in FIG. 7E, the output of the drive circuit 9 is intermittently turned on as shown in FIG.

The period T1 from tl to T2 in FIG. 7E is an appropriate cycle that can maintain the performance of the fuel cell 1.

The output of the intermittent 1 drive circuit 9 remains on until time T3 in FIG. 7E, and then turns off, stopping the electrolyte supply device 5.

Therefore, the electrolyte supply device 5 supplies an appropriate amount of fuel mixed electrolyte to the fuel cell 1 during the operation time T2.

Furthermore, after time t3 in FIG. 7, the output of the drive circuit 9 repeats the ON operation for T2 time every period T1, as shown in FIG. 7, to drive the electrolyte supply device 5 intermittently.

Next, at time 14 in FIG. 7E, a switching signal is given to the switching circuit 8, and when the switching circuit is switched from OFF to ON, the opening/closing contact 4° becomes the output of this circuit 8.

11.14.15. e6 is from off to on, opening/closing contact e
2 switches from on to off, switching the fuel cell power supply device to continuous operation, and supplying power from the fuel cell 1 to the load device 3.

As described above, in the fuel cell power supply device according to the present invention, the output of the fuel cell 1 is turned off when there is no load, and the intermittent 1 drive circuit 9 supplies appropriate fuel at appropriate intervals T1 to maintain the performance of the fuel cell 1. The mixed electrolyte is supplied for T2 hours, which can significantly reduce the catalytic decomposition of the fuel at no-load conditions at the fuel cell electrodes, and the voltage drop when starting the fuel cell is slight and no preliminary operation is required. has.

The voltage generated by the fuel cell 10 is shown in FIG. 7E.

The voltage v1 of the fuel cell 1 at the rated load increases to the no-load voltage at the same time as the load device 3 is turned off at time tl.

Since the supply of the fuel mixed electrolyte to the fuel cell 1 is stopped for a period of T□, the fuel cell voltage changes in a mountain shape according to the change in the fuel concentration in the fuel cell 1, and from the line <o-T2 T3
During this period, the electrolyte supply device operates and the fuel mixed electrolyte is replenished, so a leakage current circuit is formed through the electrolyte, and as the leakage current increases, the fuel cell voltage slightly decreases.

From then on, this operation is repeated during no-load conditions, and the fuel cell 1
is protected to prevent performance deterioration.

When load device 3 is turned on at time T3, fuel cell 1 is turned on at the same time.
The fuel cell power supply device with the circuit configuration of the present invention allows for intermittent drive. By doing so, the amount of fuel consumed could be significantly reduced as shown in FIG.

As can be seen from Fig. 8, the period T1, which is an appropriate off-time period of the electrolyte solution supply device, is more than 3 hours, but the effect is significant, but according to the research conducted by the present inventors, T□ is 8 hours. When the temperature exceeds this value, there is a tendency for the fuel utilization rate of the fuel cell 1 to decrease, the battery life to deteriorate, the start-up characteristics to deteriorate, etc., and it has been found that T□ is good for 3 to 8 hours.

In the embodiment shown in FIG. 7 according to the present invention, a case is shown in which an electrolytic solution mixed with fuel at a constant ratio is supplied by the electrolytic solution supply device 5, but the fuel and the electrolytic solution are each supplied separately to the fuel cell 1. It was found that the same effect could be obtained even if the configuration was configured to do so.

The operating time T2 of the electrolyte supply device 5 varies depending on the performance of the supply device, particularly the flow rate, but the operating time T2 is 1000 e
In the fuel cell 1 which requires an electrolyte flow rate of /min, the inventors' research has revealed that the electrolyte flow rate is 5 to 30 minutes, preferably 5 to 15 minutes.

When the circuit configuration according to the present invention is used in a hydrazine fuel cell power supply device with an output of 24y100W, T1-3
In an example of operation where the time is T2-15 minutes, as shown in Fig. 8, when the fuel consumption in conventional continuous operation is 100, the device according to the present invention consumes only 14% of the fuel, which is 86%. I was able to save money.

The characteristics of the fuel cell power supply device using the circuit configuration according to the present invention are listed as follows.

(1) Fuel consumption can be reduced, fuel tanks can be made more compact, and power supplies can be made more compact.

(2) There is less voltage drop when restarting the fuel cell, immediate output is obtained, the capacity of the secondary battery can be reduced, and preliminary operation of the fuel cell is not required, making maintenance easier.

(3) Improved fuel utilization rate as a fuel cell power supply device,
We were able to reduce power supply costs.

(4) Intermittent drive extends the life of moving parts.

(5) Improvement in fuel cell life can be expected.

FIG. 9 shows the main circuit configuration in another embodiment of the present invention.

The power supply terminal of the fuel concentration control circuit 6 is connected to the plus d of the storage battery 4 via the switching contact e1.
In this circuit configuration, the output contact e3' of the intermittent 1 drive circuit 9 is connected in parallel with the output contact e3' of the intermittent 1 drive circuit 9.

To explain the operation, when the load device 3 is on, the opening/closing contacts e4. e1 is on, the electrolyte supply device 5,
The fuel concentration control circuit 6 operates continuously.

Next, when the load device 3 is turned off, the e4*.

is turned on, the electrolyte supply device 5 and fuel concentration control circuit 6 are turned off, and the intermittent drive circuit 9 is turned on by the opening/closing contact 12.

As shown in the seventh diagram, the intermittent 1 drive circuit 9 turns on e3 and 43' at appropriate intervals T1, and operates the electrolyte supply device 5 and the fuel concentration control circuit 6 for only 12 hours.

The embodiment of the invention according to FIG. 9 shows that the amount of fuel catalytically cracked by the fuel cell plate during time T2 when the electrolyte supply device 5 is in operation at no load, and the amount of fuel catalytically cracked by the fuel cell 1 during time T1. In order to prevent the amount of fuel in the remaining electrolyte from being consumed by catalytic cracking from accumulating and increasing, the fuel concentration control circuit 6 is operated for T2 hours every cycle T1, and the fuel replenishment device 7 is activated. Fuel is supplied and the fuel concentration in the electrolyte is controlled at a constant level.

This circuit configuration is used in a fuel cell power supply device used as an emergency power source or a backup power source for communication equipment, etc., in which the off period of the load device 3 is very long. % or more, and the response of the fuel cell 1 during operation is also good.

FIG. 10 is a block diagram showing another embodiment of the intermittent drive circuit 9 according to the present invention.
A fuel concentration detection circuit 9 that generates a trigger signal in response to a signal from
a2, and a monostable multivibrator circuit that is activated by the trigger signal of the detection circuit 9a2 and operates the electrolyte supply device 5 for a time T2.

In the embodiment of the present invention shown in FIG. 10, focusing on the fact that the cell performance deteriorates when the fuel concentration in the fuel cell 1 falls below a certain value, the fuel concentration in the fuel cell is determined when the fuel cell 1 is off. It is characterized by being controlled above a certain value.

The operation will be explained. When the output of the unloaded fuel cell 1 is off and the fuel concentration in the electrolyte remaining in the fuel cell 1 becomes below a certain value due to catalytic decomposition, the fuel concentration detection section 9a1 issues a signal. , the fuel concentration detection circuit 9a2 responds to this signal and triggers the monostable multivibrator circuit 9a3.

The triggered vibrator circuit 9a3 operates the electrolyte supply device 5 connected to its output for a time T2 to replenish an appropriate fuel mixed electrolyte.

In this way, the fuel concentration within the fuel cell 1 is controlled to a certain value or higher, thereby preventing deterioration of the cell performance.

In the embodiment described above, the fuel temperature in the fuel cell 1 is maintained at a certain value or higher by replenishing the mixed fuel electrolyte, but the same effect can be achieved by replenishing the fuel cell 1 with only fuel.

According to this embodiment, the electrolyte temperature, ambient temperature, fuel cell 1
To provide a fuel cell power supply device capable of replenishing a mixed fuel electrolyte at an appropriate period even if the amount of catalytic decomposition of a fuel cell electrode plate changes due to the number of years of operation of the fuel cell, with little deterioration of cell performance, and with low fuel consumption. The value of its use is that of a dog.

When this example is used in a hydrazine fuel cell power supply device,
Good operational results were obtained by controlling the hydrazine fuel concentration in the fuel cell to 0.1% or more, preferably 0.3% or more.

Compared to conventional devices, fuel consumption was reduced by 30%, and no deterioration in battery performance or battery life was observed.

In the above embodiment, 9al is a fuel cell voltage detection section, 9
A fuel cell power supply device can be proposed in which a2 is a fuel cell voltage detection circuit and 9a3 is a monostable multivibrator circuit, and when the fuel cell voltage decreases under no load and reaches a certain value, the fuel mixed electrolyte is replenished. .

This embodiment focuses on the fact that the fuel cell voltage changes depending on the fuel concentration in the electrolyte in the fuel cell, and the device is constructed.It has the same effect as the above invention and operates well for a long period of time. It was possible to do so.

11, 12, and 13 show specific embodiments of the intermittent drive circuit 9 of the fuel cell power supply device according to the present invention.

The intermittent drive circuit 9b in FIG. 11 includes resistors R1 to R6, a capacitor C7, a C2 transistor Q1. It has an astable multivibrator circuit 9bt made up of C2, and a switch control part made up of a transistor Q3 operated by the output of this circuit 9b1, a resistor R7, a relay RL1 and its contact e3, and is connected to the input side. The operation is controlled by the opening/closing contact e2.

At present, under load, the switching contact e2 is off.

C4 is turned on and the electrolyte supply device 5 is continuously operating.

Next, when the switch is made during no-load, the open/close contact e2 is turned on and C
4 is turned off, the intermittent drive circuit 9b is turned on, and the electrolyte supply device 5 is turned off.

When the intermittent drive circuit 9b is turned on, an astable multi-byte break occurs and 9b1 oscillates, causing the transistor Q0 to become T1=0.
．． 7°C25-R is turned on for 4 hours, transistor Q2 is set to T2=0.7. Turn on C1 and R for 6 hours.

Therefore, transistor Q3 is turned on for 12 hours, relay RL1 is operated for T2 hours, and contact e3 conducts electrolysis for T2 hours.

The liquid supply device 5 is activated.

The astable multivibrator circuit consisting of the transistors Qi, j, and Q2 can be constructed using an integrated circuit, a field effect transistor, etc., and the switch control section may include a transistor, a gate turn-off thyristor, etc.

This was possible by constructing a control circuit.

FIG. 12 shows an oscillator 9C1, a counter circuit 9c2, a monostable multivibrator circuit 9c3, and a switch control section R.
An intermittent drive circuit 9C is constructed from L1 and operates in the same manner as in FIG.

FIG. 13 shows an integrated circuit timer Tb, capacitors cA, c
An intermittent drive circuit 9d comprising at least an astable multivibrator consisting of resistors R) and sRB and a switch control section RL1 performs the same operation as in FIG.

When there is no load, the switching contact e2 is turned on, and the timer T
The reset terminal 4 of b is forcibly connected to the positive power supply to cause oscillation.

T1. T2 is expressed by the following formula.

TI -0,693(f3p, +%) CA(s
ec ) T2=0.693・RB-CA (s
ec) When under load, open/close contact e is used to stop oscillation.
2 is turned off, the reset terminal 4 of the timer Tb is grounded to the negative side via the resistor R13, and the timer Tb is brought into a reset state.

FIG. 14 shows an embodiment of a fuel cell power supply device configured to further reduce performance deterioration of the fuel cell at the time of restarting a load, improve startup characteristics as a power supply device, and perform more stably.

In this embodiment, a constant voltage circuit 2 connected to the fuel cell 1 via a switching contact e5 and a contact 06/
A fuel replenishment device 7, a switching circuit 8, and a secondary battery 4 such as a storage battery are connected through a fuel supply device 7, a switching circuit 8, and a secondary battery 4 such as a storage battery. An opening/closing circuit connected to the control circuit 6, the electrolyte supply device 5, the intermittent drive circuit 9, the terminal e to the load device 3, and the fuel cell delay circuit 10, and between the electrolyte supply device 5 and the secondary battery 4 1274 A contact e3 is arranged in parallel with the contact e4 and is operated by the intermittent 1 drive circuit 9.
This is a fuel cell power supply device characterized by comprising:

FIG. 15 shows operating waveforms of the circuit according to this example.

The operation according to this embodiment will be explained.

Operations under load, when switching from load to no-load, and during no-load are the same as those shown in FIGS. 6 and 7.

Next, the switching signal causes the switching circuit 8 to switch from OFF to ON as shown in FIG. 14A.
, 11. (14,l=, -67 also turns on from off as shown in FIG. 14A, and conversely, the opening/closing contact e2
From on to off as shown in Figure B.

Therefore, the load equipment 3, the fuel concentration control circuit 6, the electrolyte supply device 5, the output of the fuel cell 1, and the fuel cell delay circuit 10 are each turned on and operate continuously, but the output of the constant voltage circuit 2 is Accordingly, the off state is maintained by the contact 16' for an appropriate period T3.

During the period T2, the fuel cell 1 only supplies a small amount of self-consumption current of the constant voltage circuit 2, and is mostly operated in a preliminary operation in a no-load state.

The 14th diagram shows the operation of contact e7.

When the output of the delay circuit 10 is turned off after 13 hours, the contact 46' of the first heater 10 is turned on, and power from the fuel cell 1 is supplied to the load equipment 3.

(FIG. 14E) During time T2, power is supplied from the storage battery 4 to the load device 3.

In this embodiment with such an operation, the preliminary operation of the fuel cell 1 at the time of restarting the load reduces the deterioration of the fuel cell performance, improves the start-up characteristics, and extends the battery life. It has the feature of reducing fuel consumption due to intermittent drive under load, and its utility value is significant.

The fuel cell delay circuit 10 has a constant value of 1 after the switching circuit 8 is turned on.
There are methods such as turning on the contact e6 after a two-hour delay, or activating the output when the voltage of the fuel cell 1 reaches a certain value, or a combination of the above methods.

switching circuit 8, fuel concentration control circuit 6, electrolyte supply device 5,
Even in a fuel cell power supply device in which the intermittent drive circuit 9, fuel cell delay circuit 10, etc. are driven by an external power source other than the secondary battery 4, for example, an AC power source or a rectified DC power source, the same effect as that of the present invention can be obtained. I was able to get results.

The switching signal of the switching circuit 8 is the current of the load equipment, the load equipment control signal, the signal due to an AC power outage in the case of backup power supply or emergency power supply,
Power for lighthouses can be obtained from sources such as sunlight.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional liquid fuel cell power supply device, FIGS. 2 to 5 are characteristic diagrams for explaining the conventional example, and FIG. 6 is a diagram of a fuel cell power supply device according to an embodiment of the present invention. A circuit diagram, FIG. 7 is a waveform diagram for explaining the circuit of FIG. 6, FIG. 8 is a characteristic diagram showing fuel consumption according to the present invention, and FIG. 9 is a circuit showing another embodiment of the present invention. 10 is a diagram showing another embodiment of the intermittent drive circuit 1, FIGS. 11 to 13 are circuit diagrams showing a specific embodiment of the intermittent drive circuit of the fuel cell power supply device according to the present invention, and FIG. The figure is a circuit diagram showing an embodiment of the fuel cell power supply device, and FIG. 15 is a waveform diagram for explaining the circuit of FIG. 14. 1...fuel cell, 2...constant voltage circuit,
3...Load equipment, 4...Secondary battery, 5
. . . Electrolyte supply device, 6 . . . Fuel concentration control circuit, 7 . . . Fuel supply device, 8 .
・Switching circuit, 9...Intermittent 1 drive circuit, 10...
...Fuel cell delay circuit, a 2 b g Cs d
*e...Terminal, 1o, el, e2. l
+, Ls, (16-117... open/close contact, e3 s 63't e6'... contact,
VFC...Fuel cell voltage, t...Time.

Claims (1)

[Claims] 1. A constant voltage circuit connected to a fuel cell via a switching contact, a switching circuit connected from an output end of the constant voltage circuit via a switching contact, a secondary battery, and an electrolyte. A refueling device to replenish, a load device connected to the output of the secondary battery via switching contacts, a fuel concentration control circuit that controls the refueling device, and an electrolytic solution containing fuel at a predetermined concentration to the fuel cell. an intermittent drive circuit that intermittently drives the electrolyte supply device and the electrolyte supply device; and a contact operated by the intermittent drive circuit that is installed in parallel with the opening/closing contact between the electrolyte supply device and the secondary battery. A fuel cell power supply device characterized in that the opening/closing contacts are operated by a switching circuit operated by a switching signal, and the intermittent drive circuit is driven during no-load conditions. 2. The intermittent drive circuit includes a timer circuit, a monostable multivibrator circuit triggered by the output of the timer circuit, and a switch control section driven by the output of the multivibrator circuit, and the monostable multivibrator circuit. 2. The fuel cell power supply device according to claim 1, wherein the output 1 drives the switch control section, and the output 2 resets the timer circuit. 3. The intermittent 1 drive circuit includes a detection circuit that detects changes in the fuel cell voltage, fuel concentration in the cell, etc., a monostable multivibrator circuit that is triggered by the output signal of the detection circuit, and a monostable multivibrator circuit that is triggered by the output signal of the multivibrator circuit. The fuel cell power supply device according to claim 1, comprising a switch control section that is driven. 4. A fuel cell in which a fuel cell delay circuit is provided between a constant voltage circuit, a fuel replenishment device, a switching circuit, and a secondary battery, the switching circuit is activated by a switching signal, and the opening/closing contacts are operated, and the switching circuit is activated by a signal from the fuel cell. 2. The fuel cell power supply device according to claim 1, wherein the delay circuit operates a contact connected to the output of the constant voltage circuit.