JP2002056866A - Fuel cell system considering freeze proofing of cooling system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new technology for separating the water from the antifreeze cooling material to be used for cooling a fuel cell to use the separated water for the fuel cell. SOLUTION: When starting a fuel cell system, a water supply unit 130 separates the water from the antifreeze cooling material CL by using a water separating unit 80, and supplies the separated water to a fuel gas supply unit 110. In normal operation, separation of the water from the antifreeze cooling material CL is stopped, and the water generated by the electrochemical reaction inside the fuel cell 50 is supplied to the fuel gas supply unit 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technology for preventing freezing of a cooling system of a fuel cell system.

[0002]

2. Description of the Related Art Fuel cells that generate electric power by utilizing an electrochemical reaction between hydrogen and oxygen are expected as next-generation energy sources. During operation of the fuel cell (at the time of power generation), considerable heat is generated due to the electrochemical reaction. Therefore, a normal fuel cell system includes a cooling device for cooling the fuel cell.

As a cooling device for a fuel cell system, for example, Japanese Patent Application Laid-Open No. 8-184877 disclosed by the present applicant has been disclosed.
Japanese Unexamined Patent Publication (Kokai) No. H10-264, pp. 157-334 is known. In this device, the fuel cell is cooled using an antifreeze coolant containing water and ethylene glycol. Further, this fuel cell system is characterized in that water is separated from an antifreeze coolant using a water separator, and the separated water is used for humidifying fuel gas.

[0004]

In the above-mentioned prior art, there is a problem that during operation of the fuel cell system, water must be always separated from the antifreeze in order to obtain water for humidification. Therefore, for example, when the separation in the water separator is incomplete and ethylene glycol is slightly mixed into the separated water, the concentration of the antifreeze (the concentration of ethylene glycol) gradually decreases. As a result, there is a problem that the effect of preventing the coolant from freezing is also reduced.

[0005] In this conventional technique, water used in the reformer is supplied from a water tank provided separately from the cooling system. For this reason, there is a problem that it is necessary to separately take measures to prevent freezing of the water tank.

The present invention has been made to solve the above-mentioned conventional problems, and is intended to separate water from an antifreeze coolant used for cooling a fuel cell and use the separated water as fuel cell water. The purpose is to provide a new technology.

[0007]

In order to achieve at least a part of the above object, a fuel cell system according to the present invention comprises a fuel cell and a reaction used for an electrochemical reaction in the fuel cell. A reaction gas supply unit for supplying a gas, a cooling unit for cooling the fuel cell using an antifreeze coolant containing water and an antifreezing agent, and water supply to the reaction gas supply unit And a water supply unit for performing the operation. The water supply unit has a water separation unit for separating water from the antifreeze coolant, and (i) in the first predetermined operation state, uses the water separation unit to perform the antifreeze operation. Separating the water from the non-freezing coolant, and supplying the separated water to the reaction gas supply unit, and (ii) stopping the separation of the water from the anti-freezing coolant in a predetermined second operation state. At the same time, water generated by the electrochemical reaction in the fuel cell is supplied to the reaction gas supply unit.

In this fuel cell system, water is separated from the antifreeze coolant in the first operation state and supplied to the reaction gas supply unit, but water is supplied from the antifreeze coolant in the second operation state. Since the separation is stopped and the water generated by the electrochemical reaction in the fuel cell is supplied to the reaction gas supply unit, there is an advantage that the water separation unit does not need to be constantly operated in the second operation state. .

[0009] The first operating state may include a time when the fuel cell system is started. At this time, in the first operation state including the start-up time, water is separated from the antifreeze coolant and supplied to the reaction gas supply unit using the separated water. If the water inside is low, it is possible to supply the required amount of water separately from the antifreeze coolant.

The first operating state includes a state in which a predetermined first temperature is lower than a first threshold, and
May include a state in which the first temperature exceeds the first threshold value. Set the first threshold to 0
If the temperature is set close to ° C., it is possible to change the water supply mode depending on whether or not the water is likely to freeze,
As a result, freezing of water can be more easily prevented.

In the first operation state, the water supply unit adjusts the pressure of the antifreeze coolant on at least one of an inlet side and an outlet side of the water separation unit, thereby controlling the water separation. It is preferable to have a water amount adjusting unit for adjusting the amount of water separated in the unit. In this mode, the amount of water generated by the water separation unit can be controlled, and the amount of water existing in the fuel cell system can be adjusted.

Further, the water supply section further collects the coolant tank for containing the antifreeze coolant and the antifreeze coolant discharged from the water separation section in the coolant tank. It is preferable to have a piping system for this. In this embodiment, the storage and recovery of the antifreeze coolant can be performed more easily.

[0013] The water supply unit further includes a water tank for storing the water separated by the water separation unit.
Preferably, water in the water tank is supplied to the reaction gas supply unit. If a water tank is provided, storage, supply, and recovery of water can be performed more easily.

It is preferable that the water supply unit recovers the water in the water tank into the antifreeze coolant in the cooling unit after the operation of the fuel cell is stopped. Further, it is preferable that, after the operation of the fuel cell is stopped, the water supply unit recovers water generated by an electrochemical reaction in the fuel cell into the antifreeze coolant in the cooling unit. . In such an embodiment, when the operation of the fuel cell system is stopped, water does not exist alone in the fuel cell system, so that the freezing prevention effect can be further enhanced.

[0015] The water supply unit may be configured to recover the water in the antifreeze coolant such that a predetermined second temperature becomes equal to or lower than a second threshold value after the operation of the fuel cell is stopped. May be executed at the time of execution. In this way, it is possible to recover water into the antifreeze coolant only when necessary to prevent water from freezing. Therefore, when the possibility of freezing is small, it is possible to reduce the need to separate water from the antifreeze coolant at the time of starting the fuel cell system.

Further, even when the fuel cell system is started, when a predetermined amount or more of water is present in the water supply unit, the water supply unit stops separating water from the antifreeze coolant. You may do so. By doing so, the time for separating water can be omitted, and thus the start-up period of the fuel cell system can be shortened.

The water supply section may further include a heating section for heating the water separation section to prevent freezing. In this mode, it is possible to more reliably prevent the freezing.

The fuel cell system further includes a concentration measuring unit for measuring a concentration index value substantially indicating a concentration of the antifreezing agent in the antifreezing coolant, And a warning unit for giving a warning indicating that it is necessary to supply either one of the antifreezing agent and water to the cooling unit according to the measured value of the concentration of the water. In this mode, it is possible to warn the user of the replenishment of the antifreeze and the water.

[0019] The warning unit is configured to keep the predetermined third temperature at the third level even when it is determined from the measured value of the concentration of the antifreezing agent that the antifreezing agent needs to be replenished. When the threshold value is exceeded, the generation of the warning may be stopped. In this embodiment, the warning is stopped when there is little possibility of freezing, so that it is possible to reduce the number of times of giving the user unnecessary worries.

The present invention can be realized in various modes, for example, a fuel cell system, a method of operating a fuel cell system, a method for generating a reaction gas for a fuel cell, and a method for producing a fuel cell. It can be realized in various modes such as a method of treating a coolant.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described based on examples in the following order. A. First embodiment: B. Second embodiment: C.I. Modification:

A. First Embodiment FIG. 1 is a block diagram showing a configuration of a fuel cell system 100 according to a first embodiment of the present invention. The fuel cell system 100 includes a fuel cell 50, a fuel gas supply unit 110 for supplying the fuel gas FG to the fuel cell 50, and a cooling unit for cooling the fuel cell 50 using the antifreeze coolant CL. 120, and a water supply unit 130 that extracts water from the antifreeze coolant CL and supplies water to the fuel gas supply unit 110. The operation of each of these units is controlled by a controller (not shown). Various operations described later are automatically executed under the control of the controller.

The fuel gas supply unit 110 includes a raw fuel tank 20 that stores a raw fuel OF for reforming, and a hydrogen-rich gas (also referred to as “reformed gas”) HR that reforms the raw fuel OF.
A reformer 30 for generating G and a humidifier 40 for humidifying the hydrogen-rich gas HRG are provided. Note that as the raw fuel OF, a hydrocarbon compound (compound containing hydrocarbon) such as methanol, gasoline, natural gas, or ether can be used.

The fuel gas FG humidified by the humidifier 40 is
The fuel gas is introduced into the fuel gas passage in the fuel cell 50 via the pipe 42. Air AR is supplied to an air passage in the fuel cell 50 by an air pump (not shown). In the fuel cell 50, the hydrogen in the fuel gas FG and the air AR
Electric power is generated by an electrochemical reaction with oxygen inside.

The cooling unit 120 includes a heat exchanger 60 for releasing the heat of the antifreeze coolant CL to the atmosphere, a coolant tank 70 containing the coolant CL, and a coolant along the circulation path 72. A pump 74 for circulating CL. As the antifreeze coolant CL, for example, an aqueous solution containing water and an antifreeze (freezing point depressant) such as ethylene glycol can be used.

The water supply unit 130 temporarily separates the water separation unit 80 for separating water from the antifreeze coolant CL used in the cooling unit 120 and the separated water SW separated by the water separation unit 80. And a water tank 90 for accommodating therein. As the water separation unit 80, for example, a device that extracts water from an aqueous solution using a filtration membrane such as a hollow fiber membrane can be used. The raw water side 80a of the water separation unit 80 has a coolant tank 7
The antifreeze coolant CL within 0 is supplied by a pump 84 via a pipe 82. The wastewater CLa after the water separation is collected in the coolant tank 70 via the return pipe 83. The return pipe 83 is provided with an electric adjustment valve 86 for adjusting the pressure and the flow rate.

The separated water SW that has infiltrated into the separated water side 80 b of the water separating section 80 is stored in a water tank 90 via a pipe 89. Further, water generated as a result of the electrochemical reaction of the fuel cell 50 (hereinafter referred to as “FC generated water”) FC
W is also stored in the water tank 90 via the pipe 92. The water WR stored in the water tank 90 is supplied to the reformer 30 via the pipe 34 by the pump 36, and is also supplied to the humidifier 40 via the pipe 44 by another pump 46. Water WR supplied to reformer 30
Is used for the steam reforming reaction in the reformer 30. The water WR supplied to the humidifier 40 is used for humidifying the hydrogen-rich gas HRG, and the humidified gas is supplied to the fuel cell 50 as a fuel gas FG.

At the bottom of the water tank 90, a return pipe 94 for collecting water in the water tank 90 into the coolant tank 70 is provided. The return pipe 94 is provided with an electric on-off valve 96. During the power generation of the fuel cell 50, the electric on-off valve 96 is kept closed. Therefore,
The water injected into the water tank 90 is stored in the water tank 90 and supplied to the fuel gas supply unit 110 by the pumps 36 and 46. On the other hand, when the fuel cell system 100 is completely stopped, the water WR in the water tank 90 is usually returned to the coolant tank 70 via the return pipe 94. Therefore, when the fuel cell system 100 is stopped, pure water does not exist in the fuel cell system 100. Note that the “pure water” in the present specification does not need to be completely pure water, but has a broad meaning including one containing some impurities. In other words, “pure water” means water that is not an aqueous solution. In this specification, “pure water” may be simply referred to as “water”.

Around the water separating section 80, a heater 88 for preventing freezing is wound. The heater 88 is connected to the separated water side 8.
0b may be arranged to heat the pipe 89. Further, the water tank 90 and other water pipes 34, 4
4, 92, a heater for preventing freezing may be provided.

FIG. 2 shows a fuel cell system 1 according to the first embodiment.
It is explanatory drawing which shows the supply state of water in the starting period of 00. Here, the “starting period” means a period of a certain length after starting. A piping system drawn with a thick line indicates a piping system used for supplying water, and a piping system drawn with a broken line indicates a piping system that is not currently used. As described above, pure water does not exist in the water tank 90 when the fuel cell system 100 is stopped. Therefore, when the fuel cell system 100 is started, water is separated from the antifreeze coolant CL using the water separation unit 80 and stored in the water tank 90.

The amount of pure water separated by the water separator 80 depends on the inlet pressure and the outlet pressure of the raw water 80a. Therefore, the amount of pure water separated can be controlled by adjusting at least one of the inlet pressure and the outlet pressure. For example, by controlling a pump 84 provided in the inlet pipe 82, the inlet pressure of the raw water side 80a can be adjusted. Further, by adjusting the opening of the adjustment valve 86 provided in the outlet pipe, the outlet pressure of the raw water side 80a can be adjusted.
The inlet pipe 82 may be provided with a device capable of adjusting the fluid resistance, such as an adjusting valve or a variable orifice. Also, a pump or a variable orifice can be used instead of the outlet-side regulating valve 96.

When a certain amount of water is accumulated in the water tank 90, the water WR is supplied to the reformer 30 and the humidifier 40 by the pumps 36 and 46, and the fuel gas supply unit 110 is operated to generate the fuel gas FG. Start. In order to determine this point, it is preferable to provide a water level gauge in the water tank 90. When the supply of the fuel gas FG starts, the fuel cell 50 starts. Thereafter, when the startup period of the fuel cell 50 ends, the fuel cell system 100 shifts to the normal operation described below.

FIG. 3 shows a fuel cell system 1 according to the first embodiment.
FIG. 7 is an explanatory diagram showing a state of water supply during normal operation of the water supply system of FIG. In the normal operation state, part of the water vapor in the fuel gas FG is released to the outside together with the exhaust gas and disappears. However, the FC generated water FCW is always generated by the electrochemical reaction in the fuel cell 50, and the FC generated water FCW
Typically exceeds the amount of water lost from the fuel cell system 100. Therefore, during normal operation, the water separation process by the water separation unit 80 is stopped, and the FC generated water FC
W is supplied to the reformer 30 and the humidifier 40.

By the way, the water separation by the water separation unit 80 is not complete, and there is a possibility that a freezing point depressant such as ethylene glycol may slightly leak to the separated water SW side. However, in the present embodiment, during normal operation, the antifreeze coolant CL
Since the water is not separated from the water, the concentration of the antifreeze in the antifreeze coolant CL may be excessively reduced by continuing the separation of the water, and the antifreeze of the coolant CL may be impaired. There is no. In addition, since the pump 84 for the water separation unit 80 is stopped during the normal operation, there is an advantage that the power for operating the pump 84 can be saved.

It should be noted that even during normal operation, the water separation unit 80
May be continued without stopping, and excess water may be returned from the water tank 90 to the coolant tank 70 via the pipe 94. Also at this time, since the separated water is returned into the coolant CL, it can be considered that the process of separating water from the coolant CL is substantially stopped.

Even when the operation of the water separation unit 80 is stopped during the normal operation, the operation of the water separation unit 80 is restarted as necessary to supply the water tank 90 with the separated water SW. You may. For example, a water level gauge may be provided in the water tank 90, and the water separating unit 80 may be operated when the water level in the water tank 90 becomes lower than a certain level. This has the advantage that there is no shortage of water to be supplied to the reformer 30 or the humidifier 40.

When the power generation by the fuel cell 50 is stopped, it becomes unnecessary to store the pure water in the system 100 in the water tank 90. Further, it is preferable that pure water does not exist in the system 100 to prevent freezing. Therefore,
After the operation of the fuel cell 50 is stopped, the electric on-off valve 96
Is opened, whereby the water in the water tank 90
And is collected in the coolant tank 70 via the Further, the water on the separated water side 80b of the water separation unit 80 is also collected in the coolant tank 70 via the water tank 90 and the pipe 94. In addition,
A pipe for returning water to the coolant tank 70 may also be provided at the bottom of the separated water side 80b of the water separation unit 80. As described above, if the water in the water tank 90 and the water separator 80 is collected in the coolant tank 70, the fuel cell system 1
Since the pure water no longer exists in 00, there is an advantage that the pure water does not freeze even if the temperature decreases.

Note that even after the operation of the fuel cell 50 is stopped, when the specific temperature (air temperature, water temperature, etc.) is higher than a predetermined threshold value close to 0 ° C., the water in the water tank 90 is stored as it is. Alternatively, water may be collected in the coolant tank 70 for the first time when the specific temperature falls below the threshold value. By doing so, the water is kept stored in the water tank 90 at a temperature (air temperature or water temperature) at which the water does not freeze, so that when the fuel cell system 100 is subsequently started, water separation is performed. There is an advantage that there is no need to separate water using the unit 80. As a result,
The startup time of the fuel cell system 100 can be reduced. The “temperature close to 0 ° C.” is preferably about 0 ° C.
A temperature in the range of from about 0C to about + 5C.

As described above, in the first embodiment, when the fuel cell system 100 is started, water is supplied to the reformer 30 and the humidifier 40 by using water separated from the antifreeze coolant CL. On the other hand, during normal operation, the separation of water from the antifreeze coolant CL is stopped, and the FC generated water FCW from the fuel cell 50 is stopped.
Is supplied to the reformer 30 and the humidifier 40.
Therefore, there is an advantage that it is not necessary to always operate the water separation unit 80 during normal operation. As a result, even if the freezing point depressant seeps into the separated water side 80b of the water separation unit 80, there is an advantage that the concentration of the antifreeze coolant CL does not excessively decrease.

In the first embodiment, after the fuel cell system 100 is stopped, the water in the system is replaced with the antifreeze coolant CL.
Since the water is collected inside, there is an advantage that the water in the system is less likely to freeze even when the temperature decreases.

B. Second Embodiment FIG. 4 is a block diagram showing a configuration of a fuel cell system 100a according to a second embodiment of the present invention. In this fuel cell system 100a,
Flow meters 85 and 87 are provided on the inlet-side pipe 82 and the outlet-side pipe 83 of the antifreeze coolant CL of the water separator 80, respectively. Further, F from the fuel cell 50 to the water tank 90
A flow meter 93 is also provided in the pipe 92 for the C generated water. Further, the coolant tank 70 contains the antifreeze coolant CL.
A concentration sensor 76 is provided for measuring the concentration of the antifreezing agent (freezing point depressant) therein. The cooling unit 120 includes a temperature sensor 77 for measuring the outside air temperature, a sensor 76,
Alarm panel 78 for displaying an alarm in response to a signal from 77
And Second Embodiment Fuel Cell System 100
Other configurations of a are the same as those of the fuel cell system 100 of the first embodiment shown in FIG.

In the fuel cell system 100a of the second embodiment, it is possible to accurately estimate the generation amount of the separated water SW from the difference between the flow rates of the flow meters 85 and 87. Therefore,
By using the pump 84, the regulating valve 86, and the like, the amount of generated separated water SW can be accurately controlled.

Further, using the flow meter 93, the FC produced water FC
Since the amount of W generated can be measured, it can be easily determined whether or not the amount of FC generated water FCW measured here has reached a predetermined value. Therefore, for example, FC generated water FC
When the measured value of the amount of W becomes equal to or more than a predetermined value, the operation of the water separation unit 80 can be stopped. It should be noted that even when the flow meter 93 is not provided, the amount of FC
It is possible to predict the amount of generated water FCW. Therefore, the generation amount of FC generated water FCW is predicted from the power generation amount of the fuel cell 50, and when the predicted amount is equal to or more than a predetermined value,
The operation of the water separation unit 80 may be stopped.

The concentration of the antifreezing agent in the antifreeze coolant CL has an appropriate range. That is, if the concentration of the antifreezing agent is too high, the circulation characteristics of the cooling unit 120 may deteriorate. On the other hand, if the concentration of the antifreezing agent is too low, the antifreezing property is reduced. Therefore, in the second embodiment, the concentration of the antifreezing agent is measured using the concentration sensor 76, and when the measured value is out of the predetermined appropriate range, a warning is displayed on the warning panel 78. For example, when the fuel cell system 100a is mounted on a vehicle, this warning is displayed on an instrument panel in a driver's seat.

This warning is for notifying the driver that it is necessary to supply an antifreezing agent (for example, ethylene glycol) or to supply water.
The warning indicating that the antifreezing agent needs to be supplied is issued when the outside air temperature measured by the temperature sensor 77 is equal to or higher than a predetermined threshold value close to 0 ° C. (for example, 5 ° C.). May be stopped. The reason is that in such a case, the coolant
Is less likely to freeze. Various conditions other than those described above can be set as conditions for stopping the generation of the warning. For example, the time when the outside air temperature is equal to or higher than a predetermined threshold value (for example, 5 ° C.) close to 0 ° C.
When it has continued for a predetermined period (for example, 24 hours),
The generation of the warning may be stopped.

It is also possible to use a sensor other than the concentration sensor 76 to measure a concentration index value (for example, conductivity) substantially indicating the concentration of the antifreezing agent in the antifreeze coolant CL. is there.

C. Modifications: The present invention is not limited to the above-described examples and embodiments, and can be carried out in various modes without departing from the gist thereof. For example, the following modifications are also possible. is there.

C1. Modification Example 1 Some of the components of the above embodiments can be omitted. For example, the water tank 90 may be omitted, and the separated water separated by the water separation unit 80 may be supplied to the reformer 30 or the humidifier 40 via a pipe as it is. However, if the water tank 90 is provided, there is an advantage that the collection and distribution of water becomes easy.

C2. Modification Example 2 As the fuel gas supply unit 110, not only a device that reforms the raw fuel gas using the reformer 30 but also any device that supplies hydrogen gas can be used. For example, instead of the raw fuel tank 20 and the reformer 30, a hydrogen storage unit that stores hydrogen such as a hydrogen gas tank or a hydrogen storage alloy can be used. In this case, since the water for reforming is unnecessary, the water separated from the antifreeze coolant CL is mainly used for humidification.

C3. Modified Example 3: In each of the above embodiments, the water separated by using the water separation unit 80 is supplied to the fuel gas supply unit 110 at the time of startup, and the water separation is stopped during normal operation to supply the FC generated water FCW with the fuel gas. To the unit 110. However, the switching of the water supply mode according to such an operation state can be performed using other conditions. For example, when the temperature of a specific portion (such as the outside air temperature or the temperature of the coolant CL) is lower than a predetermined threshold value close to 0 ° C., the water separated using the water separation unit 80 is also used during normal operation. You may make it supply to the fuel gas supply part 110. Further, when the temperature of the specific portion is higher than the threshold value, the separation of water is stopped during the normal operation, and the FC generated water FCW may be supplied to the fuel gas supply unit 110. According to such an embodiment, there is an advantage that it is possible to prevent the FC generated water from freezing when the outside air temperature is low, so that water cannot be supplied to the fuel gas supply unit 110.

When the fuel cell system 100 is started, the water supply unit 130 (ie, the water tank 90)
If a certain amount or more of water is stored, the water separation unit 80 may not perform water separation. This has the advantage that the starting period can be shortened.

As can be understood from the above description, the water supply unit 130 separates water from the antifreeze coolant in the predetermined first operation state, and supplies the separated water to the fuel gas supply unit. On the other hand, in the predetermined second operation state, the separation of the water from the antifreeze coolant may be stopped, and the FC generated water may be supplied to the fuel gas supply unit.

C4. Modification Example 4 In the above-described embodiment, the configuration example in which the hydrogen-rich gas HRG is humidified by the humidifier 40 has been described. In this case, the supply of the water WR from the water tank 90 is performed only by the reformer 30. The reason that the humidifier 40 can be omitted is that the hydrogen-rich gas HRG generated by the reformer 30 originally contains moisture. That is, it is possible to configure a fuel cell system that supplies the fuel gas to the fuel cell as a fuel gas without newly adding moisture to the hydrogen-rich gas HRG generated by the reformer 30.

On the other hand, the air AR supplied to the fuel cell
Humidification systems have also been proposed. In the above embodiment, the humidifier 40 is provided in the supply path of the hydrogen-rich gas HRG (that is, the supply path of the fuel gas FG). In addition, the humidifier is also provided in the supply path of the air AR for the fuel cell. You may do so. In this case, the water supply unit 130
Will also supply the water separated from the antifreeze coolant CL and the FC generated water to the supply unit (oxidizing gas supply unit) of the air AR. Note that a humidifier may be provided only in the supply path of the air AR without providing a humidifier in the supply path of the fuel gas FG. Further, the supply path of the fuel gas FG and the air A
The humidifier may not be provided in any of the R supply paths.

As can be understood from the above description, the water supply section of the present invention is provided with a reaction gas supply section for supplying a reaction gas to the fuel cell, and is provided with water separated from the antifreeze coolant CL and FC generation. What is necessary is just to be comprised so that water may be supplied. Here, the “reaction gas” means a gas used for an electrochemical reaction in the fuel cell, and includes a fuel gas containing hydrogen and an oxidizing gas containing oxygen. Further, the “reaction gas supply unit” includes a fuel gas supply unit that supplies a fuel gas containing hydrogen and an oxidizing gas supply unit that supplies an oxidizing gas containing oxygen.

[Brief description of the drawings]

FIG. 1 shows a fuel cell system 1 according to one embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of 00.

FIG. 2 is an explanatory diagram illustrating a water supply state during a start-up period of the fuel cell system 100 according to the first embodiment.

FIG. 3 is an explanatory diagram showing a water supply state during normal operation of the fuel cell system 100 according to the first embodiment.

FIG. 4 is a block diagram showing a configuration of a fuel cell system 100a as a second embodiment of the present invention.

[Explanation of symbols]

 20 ... raw fuel tank 30 ... reformer 34 ... pipe 36 ... pump 40 ... humidifier 44 ... pipe 46 ... pump 50 ... fuel cell 60 ... heat exchanger 70 ... coolant tank 72 ... circulation path 74 ... pump 76 ... concentration Sensor 77 Temperature sensor 78 Alarm panel 80 Water separation unit 80a Raw water side 80b Separated water side 82 Inlet piping 83 Outlet piping 84 Pump 85 Flow meter 86 Electric regulating valve 87 Flow meter 88 ... Heater 89 ... Pipe 90 ... Water tank 92 ... Pipe 93 ... Flow meter 94 ... Pipe 96 ... Electric open / close valve 100,100a ... Fuel cell system 110 ... Fuel gas supply unit 120 ... Cooling unit (cooling system) 130 ... Water supply unit AR: Air CL: Antifreeze coolant FCW: FC generated water FG: Fuel gas HRG: Hydrogen rich gas OF: Raw fuel SW: Separated water WR: Water

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiromichi Sato 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Toshihide Nakata 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F Terms (reference) 5H027 AA02 BA05 BA06 KK08 KK31 KK48 MM12

Claims (14)

[Claims] 1. A fuel cell system, comprising: a fuel cell; a reaction gas supply unit for supplying a reaction gas used for an electrochemical reaction in the fuel cell; and a water and an antifreezing agent. A cooling unit for cooling the fuel cell using a frost coolant, a water supply unit for supplying water to the reaction gas supply unit,
Wherein the water supply unit has a water separation unit for separating water from the antifreeze coolant, and the water supply unit (i) in a predetermined first operation state Is used to separate water from the antifreeze coolant using the water separation unit, and supply the separated water to the reaction gas supply unit;
(Ii) in the second predetermined operating state, stopping the separation of water from the antifreeze coolant and supplying water generated by an electrochemical reaction in the fuel cell to the reaction gas supply unit. A fuel cell system comprising: 2. The fuel cell system according to claim 1, wherein the first operating state includes a time when the fuel cell system is started. 3. The fuel cell system according to claim 1, wherein the first operating state includes a state in which a predetermined first temperature is lower than a first threshold value, and the second operating state includes a state in which the second temperature is lower than a first threshold value. The operating state includes a state in which the first temperature exceeds the first threshold value. 4. The fuel cell system according to claim 1, wherein the water supply unit is at least one of an inlet side and an outlet side of the water separation unit in the first operation state. A fuel cell system, comprising: a water amount adjusting unit that adjusts an amount of water separated in the water separating unit by adjusting a pressure of the antifreeze coolant in (1). 5. The fuel cell system according to claim 1, wherein the water supply unit further comprises: a coolant tank for containing the antifreeze coolant; and the water separation unit. A piping system for collecting the antifreeze coolant discharged from the section into the coolant tank. 6. The fuel cell system according to claim 1, wherein the water supply unit further includes a water tank for storing the water separated by the water separation unit. A fuel cell system for supplying water in the water tank to the reaction gas supply unit. 7. The fuel cell system according to claim 6, wherein the water supply unit stops operating the fuel cell.
A fuel cell system for collecting water in the water tank into the antifreeze coolant in the cooling unit. 8. The fuel cell system according to claim 1, wherein the water supply unit stops operating the fuel cell.
A fuel cell system, wherein water generated by an electrochemical reaction in the fuel cell is collected in the antifreeze coolant in the cooling unit. 9. The fuel cell system according to claim 8, wherein the water supply unit collects water into the antifreeze coolant,
A fuel cell system which is executed when a predetermined second temperature becomes equal to or lower than a second threshold after the operation of the fuel cell is stopped. 10. The fuel cell system according to claim 9, wherein the water supply unit is configured to stop the water supply unit when a predetermined amount or more of water is present in the water supply unit even when the fuel cell system is started. A fuel cell system that stops the separation of water from freezing coolant. 11. The fuel cell system according to claim 1, wherein the water supply unit further includes a heating unit that heats the water separation unit to prevent freezing. system. 12. The fuel cell system according to claim 1, further comprising: measuring a concentration index value substantially indicating a concentration of the antifreezing agent in the antifreeze coolant. A concentration measurement unit for performing, according to the measured value of the concentration of the antifreeze agent, a warning unit that warns that it is necessary to replenish the cooling unit with either the antifreeze agent or water And a fuel cell system comprising: 13. The fuel cell system according to claim 12, wherein the warning unit determines that it is necessary to replenish the antifreezing agent from a measured value of the concentration of the antifreezing agent. Also, when the predetermined third temperature is equal to or higher than a third threshold, the generation of the warning is stopped. 14. A fuel cell, a reactant gas supply unit for supplying a reactant gas used for an electrochemical reaction in the fuel cell, and an antifreeze coolant containing water and an antifreeze agent. A method of operating a fuel cell system comprising: a cooling unit for cooling the fuel cell, wherein (i) in a first predetermined operating state, separating water from the antifreeze coolant; (Ii) in a predetermined second operation state, stopping the separation of water from the antifreeze coolant and the electrochemical reaction in the fuel cell. Supplying the water generated in step (1) to the reaction gas supply unit.