JPS6110293Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention consists of a fuel cell that uses hydrazine, methanol, etc. as an oxidizing agent and oxygen, air, etc. as a reducing agent, and a voltage controller that controls and stabilizes the output voltage of this fuel cell. The present invention relates to a fuel cell power supply device that is configured in a hybrid manner by a secondary battery such as a lead storage battery or a nickel-cadmium storage battery, which is arranged in parallel with the fuel cell via the control unit.

More specifically, if the temperature of the fuel cell main body, electrolyte, or voltage control part of the fuel cell power supply device rises abnormally above the normal operating temperature, this abnormal temperature is detected and the fuel cell power supply device is quickly and reliably This invention relates to a fuel cell power supply device equipped with a protection function to prevent or reduce damage to the power supply device and the load side.

In general, a fuel cell power supply device generates more heat due to the power generation reaction of the fuel cell, but the temperature is controlled within an appropriate temperature range by a control device. However, if thermal runaway occurs for some reason, there is a risk that not only the performance of the fuel cell will deteriorate, but also an explosion or fire. In addition, abnormal heat generation in the voltage control section may lead to deterioration or destruction of the control element, causing the control section to fail. There was a risk that the system would go out of control and damage the load-side equipment.

Therefore, it is necessary to prevent abnormal temperature rises, and if the temperature rises abnormally, the fuel cell power supply device should be stopped promptly and reliably.
It was important to prevent a major accident from occurring.

Conventionally, this type of power supply device, as shown in Figure 1,
It is configured in a hybrid manner by a fuel cell 1, a voltage control section 2, and a secondary battery 3 installed in parallel with the fuel cell 1 via the control section 2, and further connected to the output side of the control section 2. A control device 5 connected to control the fuel cell 1 via a load 4 and a device start switch 8, a stopping means 6 for switching on and off a large DC current having output contacts 6A and 6B for stopping the power supply device, and The temperature detection switch 7 operates the means 6.

In such a configuration, now the output contact 6
If for some reason, for example, the electrolyte temperature rises abnormally while the fuel cell power supply device is operating with A and 6B closed and the device start switch 8 turned on, the temperature detection switch 7 is activated and the The stop means 6 having a return function is turned on. Therefore, the output contacts 6A and 6B of this stopping means 6 were changed from closed to open, cutting off the output of the fuel cell 1 and the secondary battery 3, turning off the control device 5, and stopping the fuel cell power supply device.

However, in such a configuration, the temperature detection switch 7 operates and the output contact 6 of the stop means 6
At the moment when A and 6B change from closed to open, the stop means 6 cannot obtain its driving power, so it tends to operate incompletely, and the output contacts 6A and 6B return to the closed state again, causing a chattering phenomenon. However, it was difficult to stop the fuel cell power supply device reliably and quickly.

Generally, when the stop means 6 is constructed using a non-resetting type relay, the operating time is from several tens of milliseconds to several hundred milliseconds, and in some cases, several seconds are required when the relay is used for switching high DC power. , Therefore, if sufficient driving power cannot be obtained for longer than this operating time, the relay will operate incompletely, and the output contacts 6A and 6B may not completely reverse from closed to open, or may fail after being reversed. It was found that the device returned to its original state immediately or after a certain period of time, or that a chattering phenomenon occurred in which the device repeatedly opened and closed.

Therefore, there has been a strong demand for a fuel cell power supply device in which the stopping means 6 operates reliably. In particular, fuel cell power supplies often switch on and off large DC currents, and the relays that can switch on and off large DC currents require a long operating time and require a large amount of driving power, so they are not commonly used. However, in the method of driving and holding the relay using a capacitor installed in parallel with the relay, there were problems in that the capacitor had to be very large and large in capacity, making it expensive.

The present invention solves these problems and provides a fuel cell power supply device in which a stop means is operated reliably and promptly when the temperature abnormally increases. Specifically, it is provided with means for supplying power to the stopping means for an appropriate period after the stopping means is activated.

The configuration of one embodiment of the present invention will be described below with reference to FIG. 2 and its operating waveforms shown in FIG. 3 and 3, respectively. Series circuit A of the fuel cell 1 and the output contact 6A of the stop means 6 connected to its positive terminal
is connected to the voltage control section 2. Further, at the output end of this voltage control section 2, there is an output contact 6B and a secondary battery 3.
A series circuit C is connected to the load 4.
is also connected. Further, a control device 5 that controls the operating state of the fuel cell 1 is connected to the output terminal of the voltage control section 2 via a device start switch 8.
The output terminal of this control section 2 also includes the switch 8,
A series circuit B is connected with a diode 9 connected in the forward direction, a temperature detection switch 7, and a switching means 11 having a short operating time.

Furthermore, a capacitor 10 is connected in parallel with the series circuit of the temperature detection switch 7 and the switching means 11.

Further, the stopping means 6 for switching large DC current that drives the output contacts 6A and 6B that stops the fuel cell power supply device is connected to the output contact 11 of the switching means 11.
Connect to the positive terminal of the secondary battery 3 via A.

In this embodiment, the power supply device has a hybrid configuration consisting of a hydrazine fuel cell 1 with an output of 24 V and 500 W, and a lead acid battery 3 connected to this via a voltage control section 2. A bimetal switch that turns on (closes) when the temperature rises and reaches a certain value is used, and a non-returnable electromagnetic relay (hereinafter electromagnetic relay is simply referred to as a relay) that opens and closes a large DC current is used as the stop means 6.
Furthermore, the switching means 11 is constructed using a small capacity reset type relay with a short operating time.

In the fuel cell power supply device configured as described above, when the non-resettable relay (self-holding relay) 6 constituting the stop means is in the reset state and the output contacts 6A and 6B of this relay 6 are in the closed state,
When the device start switch 8 is turned on at time _t1 , as shown by the operating waveform in FIG. 3b, the fuel cell 1 starts generating electricity, and the fuel cell 1
After the temperature of the main body, the voltage control unit 2 such as a constant voltage stabilizing circuit, or the electrolyte shown in FIG. The temperature is controlled within an appropriate temperature range by the control device 5. At this time, the capacitor 10 is charged to the output voltage V _puT of the voltage controller 2 through the diode 9 as shown in FIG. The output of the control section 2 is supplied to the load 4 as shown in FIG. 3e.

Next, a thermal runaway state occurs for some reason, and the temperature rises abnormally. For example, as shown in FIG. 3a, the electrolyte temperature Ta reaches the operating temperature of the temperature detection switch 7 at time _t2 . Then, the switch 7, which is a temperature-sensitive switch such as a bimetal switch, is reversed from off to on, and supplies driving power to the switching means 11, which is the reset type relay. When this switching means 11 is supplied with driving power, it reverses its output contact 11A from open to closed, as shown in FIG. 3d, and turns on the stop means 6. By turning on the non-resettable relay 6, which is the stopping means, the output contacts 6A and 6B of this relay 6 are set (open), and the outputs of the fuel cell 1 and lead acid battery 3 are turned off, and the output of the fuel cell power supply device is turned off. is stopped as shown in FIG. 3e, and the power supply to the load 4 is stopped. At this time, that is, when the output contacts 6A and 6B are reversed from closed to open, the drive power of the small and small capacity reset type relay, which is the switching means 11, has a short operating time, so that the output contacts 6A and 6B are opened. Although no longer supplied from either the fuel cell 1 or the lead-acid battery 3, the relay of the switching means 11 is switched to the third relay by the energy stored in the capacitor 10 arranged in parallel to the relay via the temperature detection switch 7. As shown in FIG. d, the drive is maintained for an appropriate period. The charge accumulated in the capacitor 10 is transferred to the control device 5 by the diode 9.
Alternatively, it is not supplied to the load 4 via the device start switch 8, but is supplied only to the relay 11, so that the operating time of the relay of the switching means 11 can be maintained sufficiently, and the charge in the capacitor 10 is discharged. Off-voltage (also called open-circuit voltage) of the relay
Below that, the relay is turned off.

The output contact 11A of the reset type relay constituting the switching means 11 is reversed from open to closed when the relay is turned on, and turns on the non-reset type relay for DC large current switching that constitutes the stopping means 6 ( After the output contacts 6A and 6B are reversed from closed to open, they are turned on for an appropriate period by the capacitor 10 as described above, and then turned off again.

Therefore, the non-resettable relay, which is the stopping means 6, is also driven by directly obtaining driving power sufficient to be turned on for an appropriate period determined by the capacitor 10 from the lead-acid battery 3, and then is turned on by opening the contact 11A. Then, the supply of driving power is stopped. However, since the contacts 6A and 6B of the relay are configured to be non-returnable, they remain open even after the drive power to the relay 6 is stopped, and the fuel cell power supply device remains in the stopped state.

Generally, electromagnetic devices such as relays and solenoids are
It turns on at 85% or more of the rated voltage, but conversely, it has the characteristic of maintaining the on state even if the off voltage (open circuit voltage) drops to nearly 30 to 40% of the rated voltage. As shown in Figure c, the energy of the capacitor 10 is supplied to the small and small capacity relay 11 with a short operating time, and the capacitor voltage gradually increases.
Even if Vc decreases, the relay 11 is maintained in the on state, and sufficient operating time can be obtained, and the capacitor 10 may also be small and small in capacity.

Although not shown, the non-resettable relay that is the stopping means 6 can be reset by electrical or mechanical means, and when it is in the reset state, its contacts 6A and 6B are in the reset state (closed). state).

Therefore, by using the present invention having such a configuration, it is possible to provide a fuel cell power supply device that can quickly and reliably stop the device in the event of an abnormal temperature rise.

Furthermore, according to the present invention, there is no possibility of chattering or malfunction caused by the uncertain operation of the stop means 6, and it is possible to prevent or significantly reduce the risk of fire or damage to the load or the fuel cell power supply itself due to an abnormal rise in temperature. can.

Therefore, the present invention can solve the problems of conventional devices and provide a fuel cell power supply device having a rapid, reliable and reliable overtemperature protection function.

In the embodiment of the present invention, the fuel cell 1 includes a hydrazine fuel cell with an output of 24 V and 500 W;
The control unit 2 is a transistor type constant voltage circuit, the secondary battery 3 is a lead-acid battery, 5 is a control device including an electrolyte supply pump, a temperature control device, a hydrazine fuel concentration control device, etc., and 7 is a control device in which the temperature rises and remains constant. Each uses a bimetal switch that forms a closed circuit when the value of
A 24V, operating time of 250msec is used, a small reset type relay with a short operating time is used as the switching means 11, and a capacitor 10 has a withstand voltage of 50V and a capacity of 100μ.
A fuel cell power supply device was constructed using F. Although this power supply has been in operation for three years now, it shuts down quickly and is highly reliable when the temperature rises abnormally, and there have been no incidents of fire or explosion.
Furthermore, continuous operation is possible.

In addition, the present invention includes a switching means using a reset type relay for switching small currents with a short operating time, a diode that keeps the switching means driven for an appropriate period, and a small capacitor with a small capacity. and,
The reliability of the overtemperature protection function is improved by using a stop means consisting of a non-resettable relay that opens and closes a large DC current for a relatively long operation time, and the device can be made smaller, lighter, and less expensive. The benefits are huge.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional power supply device, FIG. 2 is an explanatory diagram of a power supply device according to an embodiment of the present invention, and FIG. 3 shows its operating waveforms. DESCRIPTION OF SYMBOLS 1... Fuel cell, 2... Control unit, 3... Secondary battery, 4... Load, 5... Control equipment, 6... Stopping means, 6A, B... Output contact of stopping means 6, 7... …
Temperature detection switch means, 8... device start switch, 9... diode, 10... capacitor, 1
1...Switching means, 11A... Output contact of switching means 11.

Claims (1)

[Scope of utility model registration request] A series circuit A between the fuel cell 1 and the first contact 6A of the stop means 6 consisting of a non-resettable relay, the device start switch 8, the diode 9, and the temperature detection switch 7.
and a series circuit B with the switching means 11 consisting of a reset type relay, and a series circuit C with the second contact 6B of the stopping means 6 and the secondary battery 3, and this circuit B,
A parallel circuit of C is connected in parallel to the series circuit A via the voltage control unit 2, and a series circuit of the contact 11A of the switching means 11 and the stop means 6 is connected in parallel with the secondary battery 3, The self-holding capacitor 10 of the contact 11A is connected in parallel with the series circuit of the temperature detection switch and the switching means of the circuit B, and when the temperature of the device reaches a predetermined value or more, the temperature detection switch 7 is turned off. The fuel cell power supply device is configured such that the contact 11A of the switching means 11 is closed when turned on, and the contacts 6A and 6B are opened when the stop means 6 is turned on.