JP2000315514A - Fuel cell system thawing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly perform the start after the operation is stopped in a low-temp. environment. SOLUTION: In a fuel cell system thawing device, the passage is change over by an air passage changeover means 52 so that air heated through passing in an air heater 26 flows to a battery heating flow passage 100 when the temp. sensed by a temp. sensing means 51 is lower than the predetermined reference temp. at the time of starting fuel cell system 2, and if the temp. sensed by the sensing means 51 is over the reference level, or is going to exceed, the passage is changed over by the means 52 so that heated air flows to a piping heating passage 200. In case the fuel cell system 2 is to be started in such a low-temp. environment wherein freezing of the water in a water piping system 300 is predictable, the batter itself is first heated with less power consumption, and when the temp. exceeds the reference level, heated air is fed to the piping heating passages to thereby thaw frozen apparatuses and pipings other than battery.

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 thawing apparatus.

[0002]

2. Description of the Related Art Conventionally, a fuel cell system decompression device provided for improving the startability of a fuel cell system for a mobile body is disclosed in Japanese Patent Application Laid-Open No. 8-273689. ing. This conventional fuel cell system thawing device provides an exhaust gas introduction route along the water piping system, and if water is frozen or may freeze during the operation stop period, the reformer By heating the water piping system by introducing the exhaust gas generated by the combustion of methanol in the heater, the water is thawed to improve the water circulation.

[0003]

However, such a conventional fuel cell system thawing apparatus has the following problems. That is, in the conventional apparatus, only the water piping system is thawed, and the apparatus is not thawed by flowing heated air through the gas-liquid flow path inside the apparatus. There is a possibility that gas flow cannot be circulated due to blockage of the liquid flow path, and power generation of the fuel cell system is not performed. In addition, pumps,
Recovery of the battery capacity is necessary to continuously operate the compressor, etc., but no consideration is given to defrosting the battery. There is a risk that a device such as a compressor, which consumes particularly large power, will stop halfway and cannot be decompressed.

[0004] The present invention has been made in view of such conventional problems. When a fuel cell system is started in a low temperature environment, the battery is first warmed by heated air from a reformer immediately after the start. By recovering the capacity of the battery with the minimum power consumption, after the battery capacity is recovered, the decompression drive devices such as the air compressor and pump are operated to decompress the devices other than the battery and the piping,
An object of the present invention is to provide a fuel cell system thawing apparatus that can start a fuel cell system reliably and smoothly under a low temperature environment.

[0005]

According to a first aspect of the present invention, there is provided a fuel cell system thawing apparatus for supplying a hydrogen-rich reformed gas generated by a reformer to an anode side of a fuel cell, and supplying air sent from an air compressor to a fuel cell. In a fuel cell system that supplies power to a cathode side of a battery and generates power by a battery reaction, an air heater that heats air sent from the air compressor by combustion exhaust gas of the reformer,
As a flow path of air heated by passing through the air heater, a battery heating flow path that heats a battery and returns to the reformer, and heats equipment and piping other than the battery to the reformer. Return pipe heating flow path, temperature detecting means for detecting a representative temperature of the fuel cell system, and when the representative temperature detected by the temperature detecting means is lower than a predetermined reference temperature, the battery heating flow path Air flow switching means for switching the flow path such that the heated air flows through the air heater in the pipe heating flow path when the representative temperature is higher than the reference temperature. is there.

In the fuel cell system thawing apparatus according to the first aspect of the present invention, when starting the fuel cell system, when the representative temperature detected by the temperature detecting means is lower than a predetermined reference temperature, the air flow switching means is used. The flow path is switched so that the air heated by passing through the air heater flows into the battery heating flow path, and if the representative temperature exceeds the reference temperature, or if the representative temperature exceeds the reference temperature, the heated air is switched by the air flow switching means. Is switched to flow into the pipe heating flow path.

Accordingly, when the fuel cell system is started in a low temperature environment in which it is possible to predict that the water in the water piping system is frozen, the capacity of the battery is first increased by first heating the battery itself with low power consumption. To recover,
When the representative temperature exceeds the reference temperature, the heating air flows through the piping heating flow path for equipment other than the battery and the piping, so that the thawing procedure for thawing the equipment other than the battery and the piping can be performed. The fuel cell system below can be started reliably and smoothly.

In a fuel cell system thawing apparatus according to a second aspect of the present invention, the temperature detecting means detects the temperature of the battery as the representative temperature. By selecting a thawing procedure that accurately reflects the presence or absence of freezing of the battery, the fuel cell system can be started more reliably and smoothly in a low-temperature environment.

The fuel cell system thawing apparatus according to a third aspect of the present invention is the fuel cell system thawing apparatus according to the first aspect, further comprising a water flow path pipe, a water temperature detecting means for detecting a water temperature of the water flow path pipe, and a stop of the fuel cell system. Draining means for draining water in the water flow pipe and in equipment located in the water flow pipe when the water temperature detected by the water temperature detection means becomes lower than a predetermined reference water temperature. It is provided.

In the fuel cell system thawing apparatus according to the third aspect of the present invention, when freezing is expected while the operation of the fuel cell system is stopped, cooling water is caused to flow through the water in the water flow pipe or the inside by the water draining means. By draining the water in the equipment, it is possible to prevent water remaining in these pipes from freezing and blocking the pipes, and to start the fuel cell system more reliably and smoothly in a low-temperature environment. Be able to do it.

[0011]

According to the first aspect of the present invention, when starting the fuel cell system in a low temperature environment in which it is possible to predict that the water in the water piping system is frozen, first, a small amount of power is consumed. Thawing procedure to recover the capacity by warming the battery itself, and to thaw equipment other than the battery and piping by passing heated air through the piping heating flow path to equipment and piping other than the battery when the representative temperature exceeds the reference temperature. As a result, the fuel cell system can be reliably and smoothly started in a low temperature environment.

According to the second aspect of the present invention, since the temperature detecting means detects the battery temperature as the representative temperature of the fuel cell system, the presence or absence of freezing of the battery, which is the only energy source when the fuel cell system is started, is determined. Can be selected, and the fuel cell system can be started more reliably and smoothly in a low-temperature environment.

According to the invention of claim 3, claims 1 and 2
In addition to the effect of the above, if freezing is expected during shutdown of the fuel cell system, the water in the water flow pipe or the water in the equipment that allows the cooling water to flow through the water is drained by the water draining means. The water remaining in these pipes is prevented from freezing and blocking the pipes, so that the fuel cell system can be started more reliably and smoothly in a low-temperature environment.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a configuration of a fuel cell system and a fuel cell system decompression device attached thereto.

First, the configuration of the fuel cell system will be described.
The air compressor 1 and the cathode (K) side inlet of the fuel cell 2 are connected by a pipe 4 having an electromagnetic valve 3. The cathode outlet of the fuel cell 2 and the condenser 5 are connected by a pipe 6, and the air outlet of the condenser 5 and the air inlet of the reformer 7 are connected by a pipe 8.

The reformed gas outlet of the reformer 7 and the anode (A) side inlet of the fuel cell 2 are connected by a pipe 9. The anode-side outlet of the fuel cell 2 and the condenser 10 are connected by a pipe 11, and the reformed gas outlet of the condenser 10 and the reformed gas inlet of the reformer 7 are connected by a pipe 12.

As the cooling water passage 300, the cooling water tank 1
3 and a water inlet of the condenser 10 are connected by a pipe 15 having a pump 14. Water outlet of condenser 10 and condenser 5
The water outlet of the condenser 5 and the water inlet of the fuel cell 2 are connected by a pipe 17, and the water outlet of the fuel cell 2 and the water inlet of the cooling water tank 13 Valve 1
8 are connected by a pipe 19.

A combustion exhaust gas outlet of the reformer 7 and an exhaust line 2
0 is connected by a pipe 22 having an electromagnetic valve 21.

The configuration of the fuel cell system thawing apparatus is as follows. As a battery heating air flow path 100 for heating the battery 27, a pipe 25 having an electromagnetic valve 24 is connected to a duct 28 that covers the battery 27.
And an air inlet of the reformer 7 are connected by a pipe 29.
The exhaust outlet of the reformer 7 is connected to the pipe 22-the solenoid valve 30-the pipe 3
1—the heater 26—the solenoid valve 32—the pipe 33 is connected to the exhaust line 20.

On the other hand, the pipe heating air flow path 200 enters the inside of the condenser 10 from the heater 26 via the pipe 25, the solenoid valve 34 and the pipe 35, and further passes through the pipe 16 to the condenser 5
, And reaches the pipe 17 from here. The pipe 17 is connected to a water flow path of the fuel cell 2. Further fuel cell 2
Is connected to a pipe 29 by a pipe 45 having an electromagnetic valve 44. The flow path from the pipe 29 to the outlet of the heater 26 is common to the battery heating air flow path 100. The outlet of the heater 26 is connected to the exhaust line 20 via a solenoid valve 37-a cooling water tank 13, and further via a duct 36-a pipe 38 covering a water circulation channel.

The battery 27 is provided with a temperature sensor 51 for detecting the temperature thereof. A controller 52 controls the compressor 1 and the pump 14 in accordance with the operation mode. By controlling the degree, the fuel cell system and the thawing device are controlled.

Next, the operation of the fuel cell system and the fuel cell system thawing apparatus having the above-described configurations will be described.

<Normal Operation State> FIG. 2 shows the flow of the air system, reformed gas system, and cooling water system during normal operation.
When the controller 52 confirms that the system is warm based on the temperature detected by the temperature sensor 51, the controller 52 enters the normal operation mode.

In the normal operation mode, the air compressor 1
From the fuel cell 2 via the solenoid valve 3 and the pipe 4
Is supplied to the cathode side inlet. Further, air exiting from the cathode side outlet of the fuel cell 2 is supplied to the reformer 7 from the air inlet via the pipe 6-the condenser 5-the pipe 8. Then, the combustion gas exiting from the exhaust outlet of the reformer 7 is exhausted to an exhaust line 20 via a pipe 22.

On the other hand, the hydrogen-rich reformed gas generated in the reformer 7 is supplied from the reformed gas outlet of the reformer 7 to the fuel cell 2 through the pipe 9 from the anode (A) side inlet. Then, the reformed gas flowing out from the anode side outlet of the fuel cell 2 is:
The gas is returned to the reformed gas inlet of the reformer 7 via the pipe 11 -the condenser 10 -the pipe 12.

The fuel cell 2 receives the reformed gas from the reformer 7 on the anode side and the air from the air compressor 1 on the cathode side, and emits electrons by the movement of hydrogen ions from the anode side to the cathode side. Electric power is generated by the battery reaction.

In this fuel cell power generation, the pump 14 is activated, and the cooling water stored in the cooling water tank 13 flows through the water circulation channel 300 to cool the fuel cell 2 to an appropriate temperature.

<During start-up operation> FIG.
A heated air flow path 100 for heating the battery 27 is shown. The controller 52 checks the temperature detected by the temperature sensor 51, and determines that the operation has been stopped in a low-temperature environment, the cooling water has been frozen, and that a start command has been issued in a state where there is a possibility of freezing, First, the heating operation of the battery 27 is preferentially performed.

In the heating operation of the battery 27, the reformer 7 is operated to burn the air and the raw material gas supplied thereto, and the exhaust combustion gas is supplied to the pipe 22-electromagnetic valve 30-pipe 31-heater. Vessel 26-solenoid valve 32-piping 33
Through the exhaust line 20; On the other hand, the air from the compressor 1 flows through the air flow path 100 to the air inlet of the reformer 7 via the solenoid valve 23, the heater 26, the pipe 25, the solenoid valve 24, the battery duct 28, and the pipe 29.

As a result, in the heater 26, the air from the compressor 1 is heated by the heat of the exhaust combustion gas from the reformer 7, and the heated air passes through the battery duct 28 through the air flow path 100. The battery 27 is heated to recover its capacity.

In this start-up operation, only the power of the compressor 1 and the control power of the solenoid valve are required, so that the battery 27 whose capacity is reduced due to low temperature can supply the required power.

The heating operation of the battery 27 ends when the temperature detected by the temperature sensor 51 rises to a temperature at which the capacity of the battery 27 can be recovered, and then the operation shifts to a thawing operation.

<Thawing Operation> When the heating operation of the battery 27 is completed, the controller 52 forms the piping heating flow path 200 shown in FIG.
The operation shifts to the thawing operation for thawing the water inside.

In this thawing operation, the air and the raw material gas supplied thereto are burned by operating the reformer 7, and the exhaust combustion gas is supplied to the pipe 22-the solenoid valve 30-the pipe 3
1-heater 26-cooling water tank 1 via solenoid valve 37
3 to defrost the cooling water in the cooling water tank 13.
Further, the exhaust combustion gas is transferred from the cooling water tank 13 to the water circulation passage 3.
The gas is passed through the exhaust line 20 via the duct 36 and the pipe 38 which cover 00. On the other hand, the heater 2
6. Air heated by exhaust combustion gas in 6, pipe 2
5 and 35, through the internal flow paths of the condensers 10 and 5, pipe 17
Through. Further, the heated air passes from the pipe 17 through the water flow path of the fuel cell 2, passes through the pipe 45 and the solenoid valve 44, passes through the pipe 29, and reaches the air inlet of the reformer 7.

Thus, the cooling water in the cooling water tank 13 and the water
00, and further, the moisture in the equipment located in the water circulation channel 300 can be thawed.

After the thawing operation has been continued for a certain period of time, the controller 52 shifts to the normal operation mode and starts the normal operation.

As described above, in the fuel cell system thawing apparatus according to the first embodiment, the air from the air compressor 1 is heated by the heater 26 utilizing the combustion exhaust gas of the reformer 7, and the heating is performed. The battery 27 is heated by the generated air,
Released to the exhaust line 20 via the reformer 7 and the heater 26,
A flow path 100 dedicated to battery heating, in which power consumption of the compressor 1 at the start of startup can be reduced by minimizing pressure loss, and a device other than the battery 27 and a water flow path 30
Since the system is provided with a flow path 200 for defrosting 0, immediately after the system is started, only the battery 27 is heated to recover the capacity that has been reduced at a low temperature. The water channel can be thawed, and the fuel cell system can be started reliably even in a low temperature environment.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the water circulation channel 3
A drain valve 40 is provided at a position lower than the position 00 (in the middle of the pipe 17), and a shutoff valve 41 for shutting off the flow of water to the pipe 17 and flowing water to the drain valve 40 side is provided. In addition, a water tank 42 for storing water falling from the drain valve 40 is provided.
It is characterized in that a water temperature sensor 43 for detecting the temperature of the water flowing through zero is provided. Other configurations are the same as those of the first embodiment shown in FIG.

The fuel cell system according to the second embodiment operates similarly to the first embodiment. The fuel cell system thawing device operates in the same manner as in the first embodiment at the time of starting the fuel cell system and at the time of cooling water thawing operation.

The fuel cell system thawing apparatus according to the second embodiment is characterized in that it operates as follows particularly when the water temperature during the operation stop period decreases. While the operation is stopped, the water temperature sensor 43 detects the water temperature in the water circulation channel 300 with the water temperature sensor 43 and outputs the detected water temperature to the controller 52. When the detected water temperature has dropped to a temperature at which the cooling water may freeze, the controller 52 closes the shut-off valve 41, opens the drain valve 40, activates the pump 14, and discharges the cooling water in the cooling water tank 13 into water. Collected in tank 42.

Accordingly, the water in the water circulation path 300 is kept in the water circulation path 300 until the water drops to a temperature close to the freezing temperature, so that the pipes and the flow path inside the apparatus can be kept warm with water having a high specific heat. It is possible to shorten the time required for the piping and equipment to be exposed to a temperature below the freezing point, to suppress the progress of freezing, and to collect water in the water circulation channel 300 when the water temperature decreases to a certain extent, thereby freezing the water. The resulting destruction of equipment and piping can be prevented, and the thawing operation time at the time of subsequent startup can be shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a normal operation state of the fuel cell system according to the embodiment.

FIG. 3 is a block diagram showing a battery heating operation state of the fuel cell system thawing apparatus in the embodiment.

FIG. 4 is a block diagram showing a thawing operation state of the fuel cell system thawing apparatus in the embodiment.

FIG. 5 is a block diagram showing a configuration according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Fuel cell 5 Condenser 7 Reformer 10 Condenser 13 Cooling water tank 14 Pump 26 Heater 27 Battery 28 Duct 40 Drain valve 42 Water tank 43 Water temperature sensor 50 Temperature sensor 51 Controller 100 Battery heating flow path 200 Pipe heating Channel 300 Water circulation channel

Claims (3)

[Claims] 1. A fuel cell, wherein a hydrogen-rich reformed gas generated by a reformer is supplied to an anode side of a fuel cell and air sent from an air compressor is supplied to a cathode side of the fuel cell to generate electric power by a cell reaction. In the system, an air heater that heats air sent from the air compressor by a combustion exhaust gas of the reformer, and a battery as a flow path of air that has been heated by passing through the air heater, heating a battery, A battery heating flow path returning to the reformer and a piping heating flow path for heating equipment and piping other than the battery and returning to the reformer; a temperature detecting means for detecting a representative temperature of the fuel cell system; When the representative temperature detected by the detecting means is lower than a predetermined reference temperature, the representative temperature is higher than the reference temperature in the battery heating flow path. In such a case, the fuel cell system decompression device includes an air flow path switching means for switching the flow path so that the heated air passing through the air heater flows through the pipe heating flow path. 2. The fuel cell system thawing device according to claim 1, wherein the temperature detecting means detects the temperature of the battery as the representative temperature. 3. A water flow path pipe, a water temperature detection means for detecting a water temperature of the water flow path pipe, and a water temperature detected by the water temperature detection means while the fuel cell system is stopped is lower than a predetermined reference water temperature. 3. The fuel cell system according to claim 1, further comprising: a water draining unit configured to drain water in the water flow path pipe and in a device located in the water flow path pipe when the temperature of the fuel cell pipe becomes low. 4. Thawing device.