JP2024024238A - fuel cell device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell device that can appropriately perform antifreeze operation when the operation is stopped due to abnormality occurrence.

SOLUTION: A fuel cell device 100 comprises a first temperature sensor TH7 that detects the outside temperature or a temperature correlated with the outside temperature, second temperature sensors TH5 and TH6 that detect the temperature of water in a water path, and a control device 30 that determines whether the detection results of the first temperature sensor TH7 or the second temperature sensors TH5 and TH6 satisfy antifreeze operation conditions and controls the antifreeze operation. In the case in which the fuel cell power generation is stopped due to an abnormality being detected, when the abnormality is not an abnormality that makes it impossible to perform the antifreeze operation, and the antifreeze operation conditions are satisfied within a predetermined period before the abnormality occurs, the control device 30 executes the antifreeze operation.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a fuel cell device.

2. Description of the Related Art Fuel cell devices are known that generate power using hydrogen-containing fuel gas and oxygen-containing gas (air) and supply the electricity to the outside, and heat is discharged from the fuel cell as the power is generated. Therefore, a fuel cell device is equipped with a heat exchanger that exchanges heat between the waste heat from the fuel cell and a heat medium, a circulation flow path through which the heat medium circulates, and a heat storage tank that stores the heat medium. The waste heat generated by the system is recovered into a heat medium and stored in a heat storage tank, and this heat medium is used for hot water supply, space heating, etc. Additionally, water is generally used as the heat medium.

If the heat medium (water) circulating within the fuel cell device freezes, it may damage the circulation flow path or cause malfunction. Therefore, when it is predicted that there is a risk that the water may freeze, an antifreeze operation is performed to prevent freezing.

For example, Patent Document 1 includes a temperature detector that detects the temperature of water, a water circulator and a water heater provided in a circulation path, and the temperature detector detects water temperature below a threshold value. Discloses a method of performing a water circulation operation in which a water circulator is driven to circulate water in a circulation path and a heating operation in which a heater is operated to heat water when it is determined that antifreeze operation is necessary. has been done. In addition, even when power generation operation is stopped due to some abnormality in the fuel cell device, freezing is prevented while operation is stopped by determining whether or not antifreeze operation is necessary based on the temperature detected by the temperature detector. be done.

Patent No. 5179652

However, in the fuel cell device having the above configuration, if an abnormality also occurs in the temperature sensor during a shutdown due to an abnormality, there is a possibility that the antifreeze operation cannot be performed appropriately.

The present invention is intended to solve the above problems, and provides a fuel cell device that can appropriately perform antifreeze operation even when the operation is stopped due to the occurrence of an abnormality and an abnormality has also occurred in the temperature sensor. The purpose is to provide.

The present invention provides a fuel cell module equipped with a fuel cell that generates power using fuel gas and oxygen-containing gas;
A water route through which water flows,
a first temperature sensor that detects outside temperature or a temperature correlated with outside temperature;
a second temperature sensor that detects the temperature of water in the water path;
A control device that determines whether the detection result of the first temperature sensor or the second temperature sensor satisfies antifreeze operation conditions and controls an antifreeze operation that prevents freezing in the water path,
When the control device stops power generation of the fuel cell due to the detection of an abnormality, the control device determines that the abnormality is not an abnormality that makes it impossible to perform the antifreeze operation, and that the antifreeze operation is performed within a predetermined period before the occurrence of the abnormality. If the antifreeze operation conditions are met, the fuel cell device executes the antifreeze operation.

By configuring as described above, the necessity of anti-freeze operation is predicted from the state within a predetermined period before an abnormal stop, so even if an abnormality occurs in the temperature sensor during an abnormal stop, anti-freeze operation can be performed. It becomes possible to do so.

FIG. 1 is a system configuration diagram of a fuel cell device of this embodiment. FIG. 3 is a diagram showing an example of anti-freezing operation conditions and anti-freezing release conditions. 12 is a flowchart for determining whether or not anti-freezing operation is necessary at the time of abnormal stop. FIG. 4 is a diagram comparing the operation of the anti-freezing operation between normal times and abnormal stoppages.

Embodiments of the present invention that are considered suitable will be briefly described by showing the effects of the present invention.

The fuel cell device of the present invention includes a first temperature sensor that detects an outside temperature or a temperature that has a correlation with the outside temperature, a second temperature sensor that detects the temperature of water in a water path, and a first temperature sensor or a second temperature sensor that detects the temperature of water in a water path. a control device that determines whether the detection result of the temperature sensor satisfies antifreeze operation conditions and controls an antifreeze operation that prevents freezing in the water path; When stopping battery power generation, if the abnormality is not an abnormality that makes it impossible to perform antifreeze operation, and the antifreeze operation conditions are met within a predetermined period before the abnormality occurs, antifreeze operation is performed. . In other words, the necessity of antifreeze operation is predicted and determined from the state within a predetermined period before the abnormal stop. As a result, even if an abnormality occurs in the temperature sensor during an operational stop and the correct temperature cannot be detected, it is possible to confirm that anti-freeze operation was necessary within the specified period before the abnormal stop. If this is detected, antifreeze operation can be performed.

Further, the predetermined period is a period that includes, as a determination target, the time period when the outside temperature is the lowest on the day or the day before the abnormality occurs. By including at least the time period when the outside temperature is the lowest on the current day or the previous day as a determination target, it is possible to predict with high probability whether or not anti-freezing operation is necessary.

In addition, it is equipped with a heater installed in the water path and a third temperature sensor that detects the temperature of the water heated by the heater, and when the heater is turned on as an antifreeze operation during an abnormal stop, the control device executes the antifreeze operation. During the operation, only the amount of electricity is changed while the heater remains on, depending on the value detected by the third temperature sensor. One of the causes of fuel cell equipment stopping abnormally is fuel gas leakage, but even if operation is stopped due to fuel gas leakage, heating by the heater can be prevented by not turning the heater ON/OFF. Prevent from causing ignition. Therefore, even during an abnormal stop, water can be heated by the heater, and freezing prevention can be effectively implemented.

It also includes a heat exchanger that exchanges heat between the waste heat of the fuel cell module and water, and a heat storage tank that stores the water heated by the heat exchanger, and the heater heats the water in the heat storage tank. possible. By placing the heater underwater, the possibility of igniting the fuel gas can be reduced as much as possible, so antifreeze operation can be carried out safely.

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

FIG. 1 is a system configuration diagram of the fuel cell device of this embodiment. The fuel cell device 100 includes a fuel cell module 1, and includes a first heat exchanger 2, a heat storage tank 3, a condensed water tank 4, a radiator 5, an air supply device 14, and a fuel supply for operating the fuel cell module 1. A plurality of auxiliary machines such as the device 15 and the reformed water supply device 16 are housed in the housing 50. It is not necessary that all of the above-described devices be housed within the housing 50; for example, the first heat exchanger 2 and the heat storage tank 3 may be provided outside the housing 50. Furthermore, a fuel cell device in which some of the above-described devices are omitted is also possible.

The fuel cell module 1 includes, inside a box-shaped storage container 10, a fuel cell 11 that generates electricity using fuel gas and oxygen-containing gas, and a reformer 12 that generates fuel gas to be supplied to the fuel cell 11. Contains and consists of.

Although the structure of the fuel cell 11 is not particularly limited, it may have, for example, a cell stack structure in which a plurality of fuel cells are arranged. The fuel cell 11 having a cell stack structure is constructed by, for example, fixing the lower end of each fuel cell to a manifold using an insulating bonding material such as a glass sealing material.

The reformer 12 steam-reforms raw fuel gas such as natural gas or LP gas to generate fuel gas to be supplied to the fuel cell 11 . A fuel supply device 15 that supplies raw fuel gas and a reformed water supply device 16 that supplies reformed water are connected to the reformer 12, and the raw fuel gas and reformed water are heated and reformed. A reforming reaction occurs in the reactor 12, and fuel gas containing hydrogen is generated.

The fuel cell 11 is supplied with fuel gas generated by a reformer 12 and air (oxygen-containing gas) introduced by an air supply device 14 . When the fuel gas passes through the fuel cell, it reacts with the oxygen-containing gas to generate electricity. The space between the fuel cell 11 and the reformer 12 is a combustion section 13, and the fuel gas and oxygen-containing gas not used for power generation are combined in the combustion section 13 and combusted. Combustion of this fuel gas produces high-temperature exhaust gas, and the reformer 12 is heated by this heat. The exhaust gas thus generated within the fuel cell module 1 is supplied to the first heat exchanger 2.

A heat storage tank 3, a heat medium pump P1, and a radiator 5 are connected to the first heat exchanger 2 via piping, and a first heat medium circulation line HC1 is formed. A heat medium is introduced into the first heat medium circulation line HC1, and in the first heat exchanger 2, heat is exchanged between the heat medium and the above-mentioned exhaust gas to heat the heat medium. Water or the like can be used as the heat medium, and the heat storage tank 3 stores the heat medium whose temperature has increased through heat exchange. The heat medium stored in the heat storage tank 3 is sent to the heat radiator 5 and cooled, and after exchanging heat with the exhaust gas again in the first heat exchanger 2, it flows back to the heat storage tank 3. As a result, a high-temperature heat medium is stored in the heat storage tank 3 from the upper part, and temperature stratification is formed.

A replenishment channel 25 for replenishing water is connected to the heat storage tank 3. The replenishment flow path 25 is provided branching off from a supply flow path 26 connected to an external water supply source, and includes a water supply valve 25a that opens and closes the flow path. When the fuel cell device 100 is installed or when the water level in the heat storage tank 3 falls below a predetermined level during operation, tap water is supplied to the heat storage tank 3 through the supply channel 25 by opening the water supply valve 25a.

Further, the heat storage tank 3 is provided with a water level detection means 7 for monitoring the amount of water in the heat storage tank 3, and a heater 8 for heating the heat medium. As the water level detection means, a known water level sensor such as a float sensor or a capacitance sensor can be used, and the presence of water is detected when the amount of water in the heat storage tank 3 is above a predetermined amount, and when it is less than the predetermined amount. Detects when there is no water. In this embodiment, an example is shown in which the water level detection means 7 is provided at one location, but a plurality of water level detection means 7 may be provided in the vertical direction to detect water levels at multiple locations.

The heater 8 is disposed within the heat storage tank 3 and heats the water within the heat storage tank 3. For example, when the outside temperature is low and there is a risk that water may freeze inside the fuel cell device 100, it is possible to increase the water temperature and prevent freezing by energizing the heater 8. Furthermore, when the amount of power generated by the fuel cell 11 exceeds the amount of power consumed by the consumer, the heater 8 may be energized to consume the remaining power (surplus power).

Further, a condensed water tank 4 is connected to the first heat exchanger 2 via a condensed water recovery path 20. When the exhaust gas generated in the fuel cell module 1 is cooled by heat exchange, the water vapor contained in the exhaust gas is separated into water and gas, and the separated water passes through the condensed water recovery channel 20 to the condensed water tank 4. will be collected. In the condensed water tank 4, impurities are removed from the collected water through an ion exchanger (not shown), etc., to purify the water. The purified water is supplied to the reformer 12 by the water supply device 16 and used as reformed water. On the other hand, the gas from which moisture has been removed passes through the exhaust flow path 21 and is then exhausted to the outside of the casing 50.

A fuel supply device 15 that supplies raw fuel to the reformer 12 includes a first electromagnetic valve 150, a pressure sensor 151, a desulfurizer 152, a gas flow meter 153, and a fuel flow path 22 connected to a fuel supply source. Auxiliary machines such as a pump 154 and a second solenoid valve 155 are provided. A reformed water supply device 16 that supplies reformed water to the reformer 12 is provided with auxiliary equipment such as a reformed water pump 160 on a reformed water flow path 23 connected from the condensed water tank 4. The air supply device 14 that supplies oxygen-containing gas to the fuel cell module 1 is provided with auxiliary equipment such as an air filter 140, an air flow meter 141, and a blower 142 on the oxygen-containing gas flow path 24. Note that the auxiliary machines listed here are merely examples, and a configuration including other auxiliary machines may also be used.

The fuel cell device 100 also includes a second heat exchanger 6, a heating pump P2 that circulates the heat medium from the heat storage tank 3, and a second heat medium circulation line HC2 that includes piping that connects these. In the second heat medium circulation line HC2, tap water supplied from the outside via the supply channel 26 is heated by the second heat exchanger 6 using the high temperature heat medium stored in the heat storage tank 3. The heated water can be delivered via the delivery channel 26 to an external reheating device such as a water heater.

Further, the fuel cell device 100 includes a plurality of temperature detection means such as temperature sensors and thermistors for measuring the temperature of each part inside and outside the casing 50.

The channels through which the heat medium flows, such as the first heat medium circulation line HC1 and the second heat medium circulation line HC2, are provided with temperature detection means TH1 to TH6 for measuring the temperature of the heat medium.

For example, as means for detecting the temperature of the heat medium in the heat storage tank 3, a tank low thermistor TH1 and a tank high thermistor TH2 are provided. The tank low thermistor TH1 detects the temperature of the relatively low temperature heat medium in the heat storage tank 3, and is provided at the lower part of the heat storage tank 3. The tank height thermistor TH2 detects the temperature of the relatively high temperature heat medium in the heat storage tank 3, and is provided on the second heat medium circulation line HC2 near the heat storage tank 3. Further, as means for detecting the temperature of the heat medium flowing through the first heat medium circulation line HC1, a low heat medium thermistor TH3 and a high heat medium thermistor TH4 are provided. The heat medium low thermistor TH3 is provided between the heat medium pump P1 and the first heat exchanger 2, and detects the temperature of the heat medium that is cooled by the radiator 5 and flows into the first heat exchanger 2. The heat medium high thermistor TH4 is provided between the first heat exchanger 2 and the heat storage tank 3, and detects the temperature of the heat medium after passing through the first heat exchanger 2. Further, the supply flow path 26 includes an inlet thermistor TH5 that detects the temperature of water supplied from the outside, and the supply flow path 27 includes an outlet thermistor TH6 that detects the temperature of the water heated by the second heat exchanger 6. is provided.

Inside the fuel cell module 1, there is a center temperature sensor TC1 that detects the temperature of the center of the fuel cell 11, and a combustion sensor TC1 that detects the temperature of the combustion section 13 where fuel gas and oxygen-containing gas that are not used for power generation are combusted. A temperature sensor TC2 is provided.

Further, in order to detect the temperature around the fuel cell device 100, an outside temperature thermistor TH7 is provided. The outside temperature thermistor TH7 may directly measure the outside temperature, or may measure the temperature of a portion within the housing 50 that has a correlation with the outside temperature.

Note that the above-mentioned thermistor is an example of a temperature detection means, and the temperature to be detected and the location thereof are not limited to those in this embodiment. Further, temperature sensing means other than this may be provided.

Furthermore, the fuel cell device 100 is provided with a control device 30 that controls the operation of various devices, and also converts the DC power generated by the fuel cell module 1 into AC power, and uses the converted electricity externally. A power supply adjustment unit (power conditioner) 40 is provided to adjust the amount of power supplied to the load.

The control device 30 is connected to auxiliary equipment and various sensors that constitute the fuel cell device 100, and controls the operation of the fuel cell device 100 based on values detected by the various sensors and instructions from a remote controller (not shown).

The control device 30 causes the fuel cell device 100 to perform antifreeze operation when it is predicted that there is a risk that water may freeze in the fuel cell device 100. Specifically, the control device 30 executes the antifreeze operation when determining that the antifreeze operation conditions are satisfied. Furthermore, if it is determined that the anti-freezing release condition is met during the anti-freezing operation, the anti-freezing operation is stopped.

The antifreeze operation conditions and the antifreeze release conditions include the detected value of the outside temperature thermistor TH7 that detects the outside temperature or a temperature correlated with the outside temperature, and the water path (first heat medium circulation line HC1, second heat medium circulation line HC1, second heat medium circulation line The detection values of the temperature detection means TH1 to TH6 that measure the temperature of water flowing in the circulation line HC2, the supply flow path 26, and the feed flow path 27) can be included. The control device 30 compares the temperature detected by each temperature detection means with a threshold value and determines whether or not antifreeze operation is necessary.

FIG. 2 is a diagram showing an example of antifreeze operating conditions and antifreeze release conditions. In this embodiment, the anti-freeze operating conditions and the anti-freeze release conditions are configured based on the temperatures detected by the outside temperature thermistor TH7, the water inlet thermistor TH5, and the outlet thermistor TH6.

The antifreeze operation conditions are whether the outside temperature thermistor TH7 satisfies one of the following: X1°C (for example, 6°C) or lower, water inlet thermistor TH5 satisfies Y1°C (for example, 4°C) or lower, and hot water outlet thermistor TH6 satisfies Y1°C or lower. . When the antifreeze operation conditions are satisfied, the control device 30 determines that antifreeze operation is necessary, and executes the antifreeze operation. In other words, when the outside temperature is below X1° C., the antifreeze operation is executed because the outside temperature is low and there is a high possibility of freezing. In addition, if the temperature of the water flowing in from the outside or the temperature of the water flowing out to the outside is low, freezing may occur even if the outside temperature is not so low (X1℃ or higher), so antifreeze operation is required. is executed.

On the other hand, the anti-freezing release condition is that the outside temperature thermistor TH7 satisfies the following conditions: X2°C (for example, 10°C) or more, the water inlet thermistor TH5 satisfies Y2°C (for example, 10°C) or more, and the hot water outlet thermistor TH6 satisfies Y2°C or more, and the freezing is prevented. Whether the operation has been continued for 5 minutes or more (X2>X1, Y2>Y1). When the anti-freezing release condition is satisfied, the control device 30 determines that the anti-freezing operation is no longer necessary, and stops the anti-freezing operation.

In the above example, the water temperature is determined by the detected values of the inlet thermistor TH5 and the outlet thermistor TH6, but the determination condition may be the temperature detected by another temperature detection means, or the temperature condition You may add more. Further, the threshold value for determination is not limited to the above-mentioned example, and can be appropriately set in consideration of the arrangement position of the temperature detection means, etc.

In the antifreeze operation, the control device 30 increases the temperature of the water in the heat storage tank 3 by energizing the heater 8, and also drives the heat medium pump P1 and the heating pump P2 to increase the temperature of the water in the circulation line. to flow. The heater 8 may be turned ON/OFF depending on the temperature of the water; for example, it is energized when the temperature detected by the heat medium low thermistor TH3 is 30°C or less, and is turned off when it exceeds 40°C. Can be stopped. Further, in addition to the heater 8, a heater may be provided in the path through which water flows.

The above is the operation of the antifreeze operation in normal times. However, the antifreeze operation can also be performed when the power generation operation is stopped due to an abnormality occurring in the fuel cell device 100 (hereinafter, this state is referred to as abnormal stop or abnormal stop). By performing the antifreeze operation during an abnormal stop, it is possible to prevent water from freezing and damaging the water path until the abnormal stop state is canceled. However, depending on the cause of the abnormal stop, it may not be possible to perform antifreeze operation, and the temperature detection means may not operate properly, so it is necessary to determine whether or not antifreeze operation is necessary. There are different ways to do it.

At the time of abnormal stop, the control device 30 makes a determination according to the following procedure. First, the cause of the abnormal stop is not an abnormality that makes antifreeze operation impossible. If the antifreeze operation cannot be performed in the first place, the antifreeze operation is not performed. Second, the anti-freezing operation conditions must be met within a predetermined period before the abnormality occurs. When these two conditions are satisfied, antifreeze operation is executed.

Since the fuel cell device 100 stores data related to power generation operations over a certain period in the past as an operation history, based on this stored data, it is possible to check whether the anti-freezing operation conditions were met within a specified period before an abnormality occurred. can be judged. In other words, if the antifreeze operation conditions are satisfied within a predetermined period, it is determined that there is a high possibility that the antifreeze operation conditions will be satisfied even during an abnormal stop, and the antifreeze operation is executed. As a result, even if the temperature detection means is not operating normally during the abnormal stop, antifreeze operation can be performed, and damage to the device due to freezing can be avoided.

FIG. 3 is a flowchart for determining whether or not antifreeze operation is necessary at the time of abnormal stop. The flowchart starts when an abnormality occurs in the fuel cell device 100 and power generation operation is stopped.

First, it is determined whether the cause of the abnormal stop is an abnormality that makes it impossible to perform antifreeze operation (step 1). If NO in step 1, that is, if the antifreeze operation cannot be performed, the antifreeze operation is not performed and the determination flow ends. If YES in step 1, that is, execution of the antifreeze operation is possible, proceed to the next step.

Next, it is determined whether or not the temperature detected by the outside temperature thermistor TH7 has been continuously below X1° C. for 15 seconds within a predetermined period T (for example, 24 hours) before the occurrence of the abnormality (step 2). If YES in step 2, the process proceeds to step 5 to execute anti-freeze operation in order to satisfy the anti-freeze operation conditions. On the other hand, in the case of NO in step 2, it is then determined whether the temperature detected by the water entry thermistor TH5 has been detected to be below Y1° C. for 15 consecutive seconds within the predetermined period T (step 3). If YES in step 3, the process advances to step 5 and antifreeze operation is executed. On the other hand, in the case of NO in step 3, it is next determined whether the temperature detected by the hot water tap thermistor TH6 has been detected to be below Y1° C. for 15 consecutive seconds within the predetermined period T (step 4). If YES in step 4, the process proceeds to step 5 and antifreeze operation is executed. On the other hand, in the case of NO in step 4, it is determined that anti-freezing operation is unnecessary, so the determination flow ends without performing anti-freezing operation (step 6).

In this way, the control device 30 determines whether the anti-freezing operation conditions are satisfied based on the temperature detected within the predetermined period T before the occurrence of an abnormality, thereby making it possible for anti-freezing operation to be required during an abnormal stop. Determine gender. Thereby, even if the temperature detection means is not operating normally, antifreeze operation can be performed. Further, the predetermined period T is not particularly limited in time or number of days, and can be set as appropriate.

However, if the lowest temperature detected in the area around the abnormal stop was below the threshold, it can be predicted that there is a high possibility of freezing during the abnormal stop, so it is appropriate to perform antifreeze operation. be. Therefore, it is preferable that the predetermined period T includes at least a time period before the abnormal stop and when the outside temperature is the lowest. In other words, the predetermined period T is preferably a period that includes, as a determination target, the time period when the outside temperature is the lowest on the day or day before the abnormality occurs.

Further, the predetermined period T may be specified in hours (or days), or may be specified in time. If it is a time, it can be specified as "○○ hours before the abnormal stop", or if it is a time, it can be specified as "between ○:00 a.m. and ○:00 a.m.". Furthermore, the predetermined period T does not need to be constant; for example, the length of the predetermined period T can be changed depending on the outside temperature.

By the way, when the power generation operation is stopped due to the detection of an abnormality, the control device 30 determines whether or not antifreeze operation is necessary only once. Furthermore, since there is a possibility that the temperature detection means is not operating normally, the necessity of antifreeze operation is not determined based on the temperature detected after the abnormal stop. Therefore, even if the anti-freeze release condition is met during the anti-freeze operation, the anti-freeze operation will not be stopped. However, if the abnormal stop state is canceled or a new abnormality that disables the anti-freeze operation occurs while the anti-freeze operation is being performed, the anti-freeze operation is stopped. When the abnormal stop state is released, the control device 30 determines whether or not antifreeze operation is necessary using the normal determination procedure.

In this embodiment, regarding the anti-freezing operation conditions, an example is shown in which the temperature conditions during normal operation and the temperature conditions during abnormal stop are the same. However, the temperature conditions may be different between normal times and abnormal stoppages.

FIG. 4 is a diagram comparing the operation of the anti-freezing operation between a normal state and an abnormal stop state. The operation of the heat medium pump P1 and the heat supply pump P2 is the same during normal operation and during abnormal stop. Note that although the figure shows a case where the duty of the heat medium pump P1 is controlled and the rotation speed of the heating pump P2 is controlled, the method of driving the pumps is not limited to this.

The heater 8 is normally ON/OFF controlled based on the temperature detected by the heat medium low thermistor TH3. On the other hand, during an abnormal stop, the amount of current is increased or decreased based on the temperature detected by the heat medium low thermistor TH3, but it is not turned off, and the operation is different between normal times and abnormal stop.

One of the reasons why the fuel cell device 100 stops abnormally is fuel gas leakage, but if fuel gas leakage is suspected, the fuel gas may ignite when the heater is turned ON/OFF. There is sex. Therefore, by not turning the heater 8 ON/OFF during an abnormal stop, even if the operation is stopped due to a fuel gas leak, the heating by the heater 8 can be prevented from causing a fire. do. Therefore, even during an abnormal stop, the water can be heated by the heater 8, and freezing can be effectively prevented.

In addition, the fuel cell device 100 has a configuration in which the heater 8 is disposed underwater (inside the heat storage tank 3), so that the heat generating part of the heater 8 does not come into contact with the fuel gas, thereby reducing the possibility of the fuel gas catching fire. can be further reduced. Therefore, anti-freezing operation during abnormal stoppage can be performed more safely.

1 Fuel cell module 2 First heat exchanger (heat exchanger)
3 Heat storage tank 8 Heater 11 Fuel cell 30 Control device TH7 Outside temperature thermistor (first temperature sensor)
TH5 Water entry thermistor (second temperature sensor)
TH6 hot water thermistor (second temperature sensor)
TH3 Heat medium low thermistor (third temperature sensor)

Claims (4)

a fuel cell module equipped with a fuel cell that generates electricity using fuel gas and oxygen-containing gas;
A water route through which water flows,
a first temperature sensor that detects outside temperature or a temperature correlated with outside temperature;
a second temperature sensor that detects the temperature of water in the water path;
A control device that determines whether the detection result of the first temperature sensor or the second temperature sensor satisfies antifreeze operation conditions and controls an antifreeze operation that prevents freezing in the water path,
When the control device stops power generation of the fuel cell due to the detection of an abnormality, the control device determines that the abnormality is not an abnormality that makes it impossible to perform the antifreeze operation, and that the antifreeze operation is performed within a predetermined period before the occurrence of the abnormality. A fuel cell device that performs the antifreeze operation when the antifreeze operation conditions are met. 2. The fuel cell device according to claim 1, wherein the predetermined period is a period including, as a determination target, a time period when the outside temperature is the lowest on the day or the day before the abnormality occurs. a heater provided in the water flow path;
comprising a third temperature sensor that detects the temperature of the water heated by the heater,
When the heater is turned on as the antifreeze operation at the time of an abnormal stop, the control device is configured to keep the heater ON and only control the amount of current, depending on the value detected by the third temperature sensor during the antifreeze operation. 3. The fuel cell device according to claim 1 or 2, wherein: a heat exchanger that exchanges heat between the exhaust heat of the fuel cell module and water;
A heat storage tank that stores water heated by the heat exchanger,
4. The fuel cell device according to claim 3, wherein the heater is provided to be able to heat water in the heat storage tank.

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