JP2002319423A - Fuel cell temperature control device, and fuel cell starting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time used for raising the temperature of the whole part of electricity generating surface of a fuel cell up to the operation temperature. SOLUTION: An external heating operation, heating a coolant by a heating device 14, is kept in a state of off, until the temperature of the coolant, exhausted after flowing through a coolant flow path 21 of a fuel cell 11, reaches a prescribed first temperature T1 (for example, 0 deg.C). The temperature at a coolant supply inlet Tin and the temperature at a coolant exhaust outlet Tout are made to gradually increase by making the relative temperature of Tin to Tout alternately invert, and flow direction of coolant is switched by controlling the opening and shutting of forward direction electromagnetic valves 25, 26 and inverse direction electromagnetic valves 27, 28. Electric power generation of the fuel cell 11 is started when the temperature at a coolant supply inlet Tin and the temperature at a coolant exhaust outlet Tout reach a second temperature T2 (for example, 0 deg.C) or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell temperature controller and a fuel cell starting method, and more particularly to a technique for heating a fuel cell by supplying a heated heat exchange medium to the fuel cell. .

[0002]

2. Description of the Related Art Conventionally, a solid polymer membrane fuel cell has a stack (stacked) in which a plurality of cells are stacked on a cell formed by sandwiching a solid polymer electrolyte membrane between an anode and a cathode from both sides. (Hereinafter referred to as a fuel cell), hydrogen is supplied to the anode as fuel, air is supplied to the cathode as an oxidant, and hydrogen ions generated by a catalytic reaction at the anode pass through the solid polymer electrolyte membrane. Then, it moves to the cathode and causes an electrochemical reaction with oxygen at the cathode to generate power. Here, in order to maintain the ionic conductivity of the solid molecular electrolyte membrane, excess water is mixed with hydrogen supplied to the fuel cell by a humidifier or the like. Water is produced. If such water condenses in the flow path of the reaction gas, the dew condensation water may accumulate in the gas flow path of the reaction gas and block the gas flow path. Further, when the operation of the fuel cell is stopped in a state where the flow path of the reaction gas is blocked by the condensed water as described above, if the temperature of the fuel cell decreases to below freezing, the gas flow path of the reaction gas is blocked. There is a problem that the fuel cell freezes and it becomes difficult to start the fuel cell.

In order to solve such a problem, conventionally, for example, as in a polymer electrolyte fuel cell power generation system disclosed in Japanese Patent Application Laid-Open No. 2000-164233, a fuel gas is burned together with an oxidizing gas when the system is started. There is known a system for preheating the inside of a fuel cell by heating an antifreeze serving as a cooling medium of the fuel cell with the reaction heat and supplying the high temperature antifreeze into the fuel cell.

[0004]

In the polymer electrolyte fuel cell power generation system according to one example of the prior art, the flow direction of the cooling medium in the flow path of the cooling medium provided inside the fuel cell is a predetermined direction. Fixed.
Therefore, when the high-temperature antifreeze liquid is caused to flow through the flow path of the cooling medium, a temperature distribution is generated such that the temperature gradually decreases from the vicinity of the inlet to the vicinity of the outlet of the flow medium, and only the vicinity of the inlet is generated May be heated. In this case, the temperature rise is delayed in the vicinity of the outlet of the flow path, and the processing required when the entire power generation surface of the fuel cell is raised to a predetermined operating temperature, for example, a temperature for eliminating freezing inside the fuel cell. The time becomes longer, and there is a possibility that the start of the fuel cell is delayed. The present invention has been made in view of the above circumstances, and has a fuel cell temperature control device and a fuel cell starting method capable of reducing the time required for raising the entire power generation surface of a fuel cell to a predetermined operating temperature. The purpose is to provide.

[0005]

In order to solve the above-mentioned problems and to achieve the object, a temperature control device for a fuel cell according to the present invention according to the first aspect of the present invention includes a heat exchange medium (for example, In this embodiment, a medium supply means (for example, a refrigerant tank 12 and a circulation pump 13 in an embodiment described later) for supplying a cooling medium and the heat exchange medium supplied from the medium supply means are heated. A heating unit (for example, a heating device 14 in an embodiment described later) and a supply destination of the heat exchange medium heated by the heating unit are connected to a medium flow path (for example, described later) provided in the fuel cell. In the embodiment, the supply port (for example, the supply port 2 in the embodiment described later) of the medium flow path 21).
2) and a discharge port (for example, a discharge port 23 in an embodiment described later) to switch the medium supply path in which the flow direction of the heat exchange medium in the medium flow path can be reversed. (E.g., a refrigerant supply channel switching unit 15 in the embodiment described later).

According to the temperature control device for a fuel cell having the above-described structure, when the heat exchange medium heated by the heating means is caused to flow through the medium flow path provided in the fuel cell, the heat exchange medium in the medium flow path is provided. With the provision of the medium supply path switching means capable of reversing the flow direction of the fuel cell, the time required for raising the entire power generation surface of the fuel cell to a predetermined temperature can be reduced. For example, when the heat exchange medium flows in the direction from the supply port of the medium flow path to the discharge port, that is, in the forward direction, the temperature becomes higher near the supply port of the medium flow path, and the temperature gradually decreases toward the discharge port. A temperature distribution occurs. That is, the heated heat exchange medium consumes more heat energy by heat exchange near the supply port of the medium flow path,
The closer to the outlet, the smaller the amount of heat energy held for heat exchange.

Here, the flow direction of the heat exchange medium is reversed by the medium supply path switching means, and the heat exchange medium flows in the direction from the outlet of the medium flow path to the supply port, that is, in the reverse direction. Then, the heated heat exchange medium consumes more heat energy by heat exchange in the vicinity of the outlet where the temperature is relatively low, and the temperature rise rate in the vicinity of the outlet increases. By continuing this state for a predetermined time, the temperature in the vicinity of the outlet becomes higher than the temperature in the vicinity of the supply port, and the temperature distribution in the medium flow path reverses, and gradually from the vicinity of the discharge port to the vicinity of the supply port. A temperature distribution occurs in which the temperature decreases. In this case, the flow direction of the heat exchange medium in the medium flow path is returned to the forward direction again, and the above operation is repeated, whereby the entire power generation surface of the fuel cell can be quickly raised to the predetermined temperature.

According to a second aspect of the invention, there is provided a method for starting a fuel cell according to the first step of heating a heat exchange medium supplied to the fuel cell when starting the fuel cell.
In an embodiment to be described later, step S12) and the supply destination of the heat exchange medium heated in the first step are performed by using any one of a supply port and a discharge port of a medium flow path provided in the fuel cell. By switching to one, the second direction in which the flow direction of the heat exchange medium in the medium flow path is reversed.
(For example, steps S19, S21, and S23 in an embodiment described later).

According to the fuel cell starting method described above, first, the heat exchange medium supplied to the fuel cell is heated in the first step. And the heated heat exchange medium,
For example, the fuel is circulated in a direction from a supply port to a discharge port of a medium flow path provided in the fuel cell, that is, in a forward direction. Next, for example, in a state where a temperature distribution in which the temperature becomes higher near the supply port of the medium flow path and gradually decreases toward the vicinity of the discharge port occurs,
In the second step, the flow direction of the heat exchange medium in the medium flow path is reversed, and the heat exchange medium flows in the direction from the discharge port to the supply port of the medium flow path, that is, in the reverse direction.

As a result, the heated heat exchange medium consumes more heat energy by heat exchange in the vicinity of the outlet where the temperature is relatively low, and the temperature rise rate in the vicinity of the outlet increases. Then, the temperature in the vicinity of the outlet becomes higher than the temperature in the vicinity of the supply port, the temperature distribution in the medium flow path is reversed, and a temperature distribution in which the temperature gradually decreases from the vicinity of the discharge port to the vicinity of the supply port occurs. Then, the flow direction of the heat exchange medium in the medium flow path is returned to the forward direction again. By repeating the above processing, the time required to warm up the entire power generation surface of the fuel cell to a predetermined operating temperature can be reduced.

Further, according to a third aspect of the present invention, in the method for starting a fuel cell, the first step and the second step may be performed by changing a temperature of the fuel cell (for example, a refrigerant in an embodiment described later). The process is performed when the supply port temperature Tin and the refrigerant discharge port temperature Tout are equal to or lower than a predetermined first temperature (for example, a first temperature T1 in an embodiment described later). According to the above-described method for starting the fuel cell, for example, when the temperature of the fuel cell in a stopped state is reduced to below freezing and residual water in the reaction gas flow path of the fuel cell is frozen, Is set to about 0 ° C. at which the frozen state is eliminated. Until the temperature of the fuel cell reaches the first temperature, a first step of heating the heat exchange medium and a second step of switching the flow direction of the heat exchange medium in the medium flow path of the fuel cell And execute Thus, the time required to warm up the entire power generation surface of the fuel cell to the predetermined first temperature can be reduced.

Further, in the method for starting a fuel cell according to the present invention, the temperature of the fuel cell (for example, a coolant supply port temperature Tin and a coolant discharge port temperature Tout in an embodiment described later) is predetermined. A third step (for example, starting the power generation of the fuel cell when the temperature is equal to or higher than a second temperature (for example, a second temperature T2 in an embodiment described later)
The embodiment described later is characterized by including step S15). According to the above-described fuel cell starting method, for example, execution of the first step of heating the heat exchange medium and the second step of switching the flow direction of the heat exchange medium in the medium flow path of the fuel cell Time,
Alternatively, after completion of the first and second steps, power generation is started when the temperature of the fuel cell becomes equal to or higher than a predetermined second temperature.

For example, when the temperature of the fuel cell in the stopped state drops below the freezing point and the residual water in the reaction gas flow path of the fuel cell is frozen, the predetermined second temperature is released from the frozen state. Set to about 0 ° C. Thereby, a desired power generation efficiency for the fuel cell can be ensured, and after the start of power generation, the fuel cell can be heated by self-heating of the fuel cell. The energy efficiency can be improved by suppressing the consumption of heat energy as in the step (1). When the third step of starting the power generation of the fuel cell is performed, the heat exchange medium is caused to flow in a direction from the supply port to the discharge port of the medium flow path, that is, in the forward direction.
Desired power generation efficiency of the fuel cell can be secured.

Further, in the method for starting a fuel cell according to the present invention, the second step may include a step of detecting a temperature in the vicinity of the supply port and the vicinity of the discharge port (for example, a refrigerant in an embodiment described later). The flow direction of the heat exchange medium in the medium flow path is reversed based on the supply port temperature Tin and the refrigerant discharge port temperature Tout). According to the above-described method of starting the fuel cell, for example, when the temperature difference between the temperature near the supply port and the temperature near the discharge port of the medium flow path is equal to or higher than a predetermined temperature, the temperature difference is reduced. To set the flow direction of the heat exchange medium.
That is, when the temperature near the supply port is higher than the temperature near the discharge port by a predetermined temperature or more, the heat exchange medium flows in the direction from the discharge port of the medium flow path to the supply port, that is, in the reverse direction,
When the temperature in the vicinity of the outlet is higher than the temperature in the vicinity of the supply port by a predetermined temperature or more, the heat exchange medium flows in the direction from the supply port to the discharge port of the medium flow path, that is, in the forward direction. That is, since the flow path is switched according to the temperature difference between the entrance and exit of the heat exchange medium (for example, cooling water) with respect to the fuel cell, the temperature of the entire power generation surface of the fuel cell can be made uniform, and the entire power generation surface of the fuel cell can be cooled. The time required for warming up to a predetermined temperature can be reduced.

Further, in the method for starting a fuel cell according to the present invention, the second step may include reducing a heat amount supplied by the heat exchange medium supplied to one of the supply port and the discharge port. The flow direction of the heat exchange medium in the medium flow path is reversed based on the flow direction. According to the above-described method for starting the fuel cell, for example, when the amount of heat supplied (that is, the amount of heating) near the supply port of the medium flow path is equal to or more than a predetermined amount of heat, or the amount of heat that is supplied near the outlet (that is, the amount of heating heat) Is more than a predetermined amount of heat, the flow direction of the heat exchange medium is reversed. In this case, the supply heat amount is calculated based on the temperature near the supply port and the flow rate of the heat exchange medium, for example, when the flow direction of the heat exchange medium is the forward direction. In the case of the reverse direction, it may be calculated based on the temperature near the outlet and the flow rate of the heat exchange medium. That is, it is possible to prevent the amount of heating heat from being concentrated on the inlet side or the outlet side of the heat exchange medium with respect to the fuel cell, to make the temperature of the entire power generation surface of the fuel cell uniform, and to maintain the entire power generation surface of the fuel cell at a predetermined level. The time required for warming up to the temperature can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fuel cell temperature controller according to an embodiment of the present invention will be described with reference to the accompanying drawings. 1 and 2 are configuration diagrams of a temperature control device 10 for a fuel cell according to an embodiment of the present invention.
FIG. 1 is a diagram showing a circulation route when the cooling medium is circulated in the forward direction, and FIG. 2 is a diagram showing a circulation route when the cooling medium is circulated in the reverse direction. The fuel cell temperature control device 10 according to the present embodiment is mounted on a vehicle such as an electric vehicle, for example, and includes, for example, a fuel cell 11, a refrigerant tank 12, a circulation pump 13, a heating device 14, a refrigerant supply The flow path switching unit 15, the supply port temperature detector 16, the discharge port temperature detector 17, the supply port flow rate detector 18, and the discharge port flow rate detector 19 are provided.

The fuel cell 11 is different from a cell formed by sandwiching a solid polymer electrolyte membrane composed of, for example, a solid polymer ion exchange membrane between an anode and a cathode from both sides.
It is composed of a stack formed by stacking a plurality of cells, and includes a fuel electrode to which, for example, hydrogen is supplied as a fuel, and an air electrode to which air containing, for example, oxygen is supplied as an oxidant. In FIGS. 1 and 2, hydrogen and air supplied to the fuel cell 11 are described as reaction gas for convenience, and the flow path of the reaction gas in the fuel cell 11 is simplified.

Further, inside the fuel cell 11, there is provided a medium flow path 21 through which a cooling medium supplied from the outside circulates. One end of this medium flow path 21 serves as a cooling medium supply port 22, The other end is a cooling medium outlet 23.

The coolant tank 12 stores a cooling medium flowing through the medium flow path 21 of the fuel cell 11, and the cooling medium supplied to the fuel cell 11 via the circulation pump 13 flows through the medium flow path 21. During the heat exchange process, the heat is exchanged and then discharged and returned to the refrigerant tank 12 again. The heating device 14 heats the cooling medium supplied to the fuel cell 11 in a predetermined operation state described later. Here, the heating device 14 may heat the cooling medium by, for example, an electric heater or the like, and may branch a part of the reaction gas supplied to the fuel cell 11 or a part of the reaction gas discharged from the fuel cell 11. And the cooling medium may be heated by combustion heat generated by burning hydrogen with air.

The refrigerant supply flow switching unit 15 includes a heating device 14
And switches the supply destination of the high-temperature cooling medium heated by the two-way solenoid valves 25 and 26, for example.
And two reverse solenoid valves 27 and 28. Here, the forward solenoid valve 25 is provided in a flow path 29 a connecting the heating device 14 and the supply port 22 of the medium flow path 21, and the forward solenoid valve 26 is provided in the discharge port 2 of the medium flow path 21.
It is provided in a flow path 29b that connects the refrigerant tank 3 and the refrigerant tank 12. The reverse electromagnetic valve 27 is provided in a flow path 29c that branches off from a flow path 29a between the heating device 14 and the forward electromagnetic valve 25 and connects to the discharge port 23.
It is provided in a flow path 29 d branched from a flow path 29 a between the supply port 22 and the forward solenoid valve 25 and connected to the refrigerant tank 12.

That is, as shown in FIG. 1, when a heated high-temperature cooling medium is supplied to the supply port 22 of the medium flow path 21 and discharged from the discharge port 23, that is, in the case of performing a forward circulation, The two forward solenoid valves 25 and 26 are both opened, and the two reverse solenoid valves 27 and 28 are both closed. On the other hand, as shown in FIG. 2, the heated high-temperature cooling medium is supplied to the outlet 23 of the medium flow path 21 and supplied to the supply port 22.
In the case of performing the circulation in the reverse direction, that is, the two forward solenoid valves 25 and 26 are both closed,
The two opposite solenoid valves 27 and 28 are both opened.

A supply port temperature detector 16 for detecting the temperature of the cooling medium and a supply port flow detector 18 for detecting the flow rate are provided in a flow path 29a near the supply port 22 of the medium flow path 21. An outlet temperature detector 17 for detecting the temperature of the cooling medium and an outlet flow detector 19 for detecting the flow rate are provided in the flow passage 29b near the outlet 23.

The temperature control device 10 for a fuel cell according to the present embodiment has the above-described configuration. Next, the operation of the temperature control device 10 for a fuel cell, in particular, a method for starting the fuel cell will be described with reference to the accompanying drawings. I will explain while. FIG. 3 is a flowchart showing the operation of the temperature control device 10 for the fuel cell, in particular, the operation when the fuel cell 11 is started.
FIG. 5 is a flowchart showing the operation in the low-temperature start mode shown in FIG. 3, FIG. 5 is a graph showing a change in the temperature of the cooling medium, and FIG. FIG. 7 is a graph showing a change in a flag, FIG. 7 is a graph showing a change in ON / OFF of an external heating operation for heating the cooling medium by the heating device 14, and FIG. 8 is an ON in a power generation operation of the fuel cell 11. It is a graph which shows the change of / OFF.

First, in step S01 shown in FIG. 3, the ignition of the vehicle is turned on. Next, in step S02, it is determined whether the coolant supply port temperature Tin detected by the supply port temperature detector 16 near the supply port 22 of the medium flow path 21 is equal to or lower than a predetermined temperature # T0 (for example, 0 ° C.). I do. If the result of this determination is "YES", the operation proceeds to step S03, where a transition is made to a low-temperature start-up mode to be described later, and a series of processes is ended. On the other hand, if the determination result is “NO”, the process proceeds to step S04, determines that the fuel cell 11 is not in a low temperature state, and shifts to a normal startup mode in which the temperature is increased by self-heating accompanying power generation. A series of processing ends.

The low-temperature start mode in step S03 will be described below. First, in step S11 shown in FIG. 4, the refrigerant circulation pump 13 is turned on to start circulation in the forward direction, that is, the forward direction in which the cooling medium is introduced from the supply port 22 and discharged from the discharge port 23. Next, in step S12, the heating device 14
Is turned on, the temperature of the cooling medium circulating in the fuel cell 11 is increased.

Next, in step S13, the refrigerant outlet temperature Tout detected by the outlet temperature detector 17 in the vicinity of the outlet 23 becomes a predetermined temperature # T0 (for example,
0 ° C.) or less. The result of this determination is “YE
In the case of "S", the process proceeds to step S18 described later. On the other hand, if the result of this determination is “NO”, then step S1
Proceed to 4 to supply the reaction gas to the fuel cell 11. Then, in step S15, the power generation of the fuel cell 11 is started to bring the fuel cell 11 into an idling operation state. Next, step S1
In 6, the heating device 14 is turned off. Then, in step S17, it is determined that the vehicle is in a runnable state, and the series of processing ends.

On the other hand, in step S18, the temperature difference (Tin-Tout) between the refrigerant supply port temperature Tin and the refrigerant discharge port temperature Tout is equal to the predetermined temperature #T (for example, 5 ° C.).
It is determined whether or not this is the case. If this determination is "NO", the flow returns to step S13. On the other hand, if the result of this determination is “YES”, the flow proceeds to step S19, where the flow direction of the cooling medium in the medium flow path 21 is set to the reverse direction.
That is, the forward solenoid valves 25 and 26 are closed, and the reverse solenoid valves 27 and 28 are open, so that the outlet 2
The circulation in the reverse direction, in which the cooling medium is introduced from 3 and discharged from the supply port 22, is started.

Next, in step S20, the coolant supply port temperature Tin near the supply port 22 becomes equal to the predetermined temperature #T.
It is determined whether it is 0 (for example, 0 ° C.) or less. If this determination is "YES", the flow proceeds to step S22 described later. On the other hand, if the result of this determination is "NO", the flow proceeds to step S21, where the flow direction of the cooling medium in the medium flow path 21 is set to the normal rotation direction. That is, the forward solenoid valve 2
By opening the reverse solenoid valves 27 and 28 with the 5, 5 open state, and closing the reverse electromagnetic valves 27, 28, the circulation in the forward direction, in which the cooling medium is introduced from the supply port 22 and discharged from the discharge port 23, is started.
Then, the process proceeds to step S14.

In step S22, the temperature difference (Tout) between the refrigerant outlet port temperature Tout and the refrigerant supply port temperature Tin is determined.
It is determined whether or not (t-Tin) is equal to or higher than a predetermined temperature #T (for example, 5 ° C.). If this determination is "NO", the flow returns to step S20. On the other hand, if the determination result is “YES”
In the case of, the flow proceeds to step S23, and the flow direction of the cooling medium in the medium flow path 21 is set to the normal rotation direction.

Next, in step S24, the refrigerant outlet temperature Tout near the outlet 23 is reduced to a predetermined temperature #.
It is determined whether the temperature is equal to or lower than T0 (for example, 0 ° C.). If this determination is "YES", the flow proceeds to step S25.
On the other hand, if the result of this determination is “NO”, then step S
Proceed to 14. In step S25, the temperature difference (Tin) between the refrigerant supply port temperature Tin and the refrigerant discharge port temperature Tout
−Tout) is equal to or higher than a predetermined temperature #T (for example, 5 ° C.). If this determination is "NO", the flow returns to step S24. On the other hand, if the determination result is “YES”
In the case of, the process returns to step S19.

That is, for example, in a low-temperature start mode in which the fuel cell 11 is started from a temperature below freezing,
As shown in FIG. 7, the temperature of the cooling medium discharged after flowing through the medium flow path 21 of the fuel cell 11 becomes equal to a predetermined first temperature T.
Until the temperature reaches 1 (for example, T1 = # T0 = 0 ° C.) (for example, until time t5 shown in FIG. 7), the external heating operation of heating the cooling medium by the heating device 14 is turned on. Then, for example, as shown in FIG.
As shown in FIG. 6, the flow direction of the cooling medium in the medium flow path 21 is switched so that the relative temperatures of the refrigerant outlet temperature Tout and the refrigerant outlet temperature Tout alternately reverse while the two temperatures Tin and Tout gradually increase. . This switching operation is continued until the refrigerant supply port temperature Tin and the refrigerant discharge port temperature Tout reach a predetermined temperature # T0 (for example, 0 ° C.). Then, as shown in FIG. 8, the temperature of the cooling medium discharged after flowing through the medium flow path 21 of the fuel cell 11, that is, the coolant supply port temperature Tin and the coolant discharge port temperature Tout are equal to a predetermined second temperature T2 (for example, , T2 = # T0 = 0 ° C.) or more (for example, at time t5 shown in FIG. 8), the power generation by the fuel cell 11 is started.

As described above, according to the fuel cell temperature control device 10 of the present embodiment, the cooling medium heated by the heating device 14 is supplied to the medium flow channel 2 provided in the fuel cell 11.
1 when the coolant is supplied to the fuel cell 1, the coolant supply channel switching unit 15 that switches the direction of flow of the cooling medium in the medium channel 21 between a forward direction and a reverse direction is provided.
The time required to raise the entire power generation surface 1 to a predetermined temperature # T0 (for example, 0 ° C.) can be reduced. Further, according to the method for starting the fuel cell according to the present embodiment,
While alternately reversing the relative temperature between the refrigerant supply port temperature Tin and the refrigerant discharge port temperature Tout, the two temperatures Tin, Tout
Is gradually increased to a predetermined temperature # T0 (for example, 0 ° C.), and the flow direction of the cooling medium in the medium flow path 21 is repeatedly switched, so that the entire power generation surface of the fuel cell 11 is quickly cooled to the predetermined temperature # T0. (For example, 0 ° C.).

In the above-described embodiment,
The upper limit temperature at which the external heating operation of heating the cooling medium by the heating device 14 is turned ON, and the operation of switching the flow direction of the cooling medium in the medium flow path 21 by the refrigerant supply flow path switching unit 15 is repeated, that is, the predetermined first temperature. The temperature T1 and the lower limit temperature at which the fuel cell 11 starts power generation, that is, a predetermined second
Although the temperature T2 is set to the same temperature, for example, 0 ° C., which is a temperature at which the frozen state of the fuel cell 11 is eliminated, the temperature is not limited to this and may be set to different temperatures. For example, FIG. 9 is a graph showing a temperature change of a cooling medium according to a modification of the fuel cell starting method of the present embodiment, and FIG. 10 is a graph showing a medium flow according to a modification of the fuel cell starting method of the present embodiment. Road 2
FIG. 11 is a graph showing a change of a reversal flag for instructing a reversal of the flow direction of the cooling medium in FIG. 1. FIG. 11 heats the cooling medium by a heating device 14 according to a modification of the fuel cell starting method of the present embodiment. FIG. 12 is a graph showing a change in ON / OFF of the external heating operation. FIG.
It is a graph which shows the change of N / OFF.

That is, as shown in FIG. 11, the predetermined first temperature T1 (for example, 5 ° C.) may be set to be higher than the predetermined second temperature T2, or as shown in FIG.
The predetermined second temperature T2 (for example, −5 ° C.) may be set to a temperature lower than the predetermined first temperature T1. In this case, the temperature raising operation of the fuel cell 11 can be performed based on the heat exchange by the heated high-temperature cooling medium and the self-heating accompanying the power generation of the fuel cell 11. 11 can be raised to a predetermined temperature. Further, the upper limit temperature at which the operation of switching the flow direction of the cooling medium in the medium flow path 21 by the refrigerant supply flow path switching unit 15 may be set to a temperature different from the predetermined first temperature T1. In this case, the fuel cell 1
At the start of the power generation of No. 1, it is preferable that the cooling medium is circulated in the direction from the supply port 22 of the medium flow path 21 to the discharge port 23, that is, in the forward direction, and the desired power generation efficiency of the fuel cell 11 is ensured. be able to.

In the above-described embodiment,
The timing for switching the flow direction of the cooling medium in the medium flow path 21 by the refrigerant supply flow path switching unit 15 is set based on the temperature difference between the refrigerant supply port temperature Tin and the refrigerant discharge port temperature Tout, but is not limited thereto. Instead, the timing may be set at an appropriate timing based on, for example, the amount of heat supplied by the cooling medium, or the switching may be performed, for example, every predetermined time (for example, one minute). Here, for example, when the switching timing is set based on the amount of heat supplied by the cooling medium, when the cooling medium discharged from the medium flow path 21 detected by the supply port temperature detector 16 and the discharge port temperature detector 17 is used. The amount of heat supplied by the cooling medium, which can be estimated based on the temperature and the flow rate of the cooling medium detected by the supply port flow detector 18 and the discharge port flow detector 19, is set, for example, so as to decrease as the supply heat increases. A map with the predetermined switching timing (period) may be set in advance, and the switching timing may be set according to a map search of this map.

In the above-described embodiment,
Based on the refrigerant supply port temperature Tin and the refrigerant discharge port temperature Tout, the timings of the operation and stop of the heating device 14, the switching operation in the refrigerant supply channel switching unit 15, the power generation operation of the fuel cell 11, and the like are set. However, the present invention is not limited to this. Based on the temperature of the fuel cell 11, for example, the temperature of the power generation surface estimated from the coolant supply port temperature Tin and the coolant discharge port temperature Tout, or the temperature at a predetermined position inside the fuel cell 11, for example. It may be determined.

[0037]

As described above, according to the fuel cell temperature control apparatus of the present invention, the heat exchange medium heated by the heating means is supplied to the medium flow path provided in the fuel cell. By providing a medium supply path switching unit that allows reversal of the flow direction of the heat exchange medium in the medium flow path during distribution, the time required to raise the entire power generation surface of the fuel cell to a predetermined temperature is provided. Can be shortened.

According to the fuel cell starting method of the present invention, the process of reversing the flow direction of the heat exchange medium in the medium flow path of the fuel cell is repeated.
The time required to warm up the entire power generation surface of the fuel cell to a predetermined operating temperature can be reduced. Further, according to the method for starting a fuel cell of the present invention, the first step of heating the heat exchange medium until the temperature of the fuel cell reaches the first temperature; By executing the second step of switching the flow direction of the heat exchange medium in the flow path, the time required to warm up the entire power generation surface of the fuel cell to the predetermined first temperature can be reduced. it can. Further, according to the fuel cell starting method of the present invention, the first step of heating the heat exchange medium and the switching of the flow direction of the heat exchange medium in the medium flow path of the fuel cell are performed. The power generation is started when the temperature of the fuel cell becomes equal to or higher than the predetermined second temperature at the time of executing the step 2 or after the end of the first and second steps. Efficiency can be secured early.

Further, according to the fuel cell starting method of the present invention, the flow direction of the heat exchange medium is set based on the temperature near the supply port and near the discharge port of the medium flow path, Since the flow path is switched according to the temperature difference between the entrance and exit of the heat exchange medium with respect to the fuel cell, the temperature of the entire power generation surface of the fuel cell can be made uniform, and when the entire power generation surface of the fuel cell is warmed up to a predetermined temperature. Can be shortened. Further, according to the fuel cell starting method of the present invention described in claim 6, the amount of heat supplied (that is, the amount of heating) near the supply port of the medium flow path or the amount of heat supplied (that is, the amount of heating heat) near the outlet of the medium flow path. By setting the flow direction of the heat exchange medium on the basis of the heat exchange medium, it is possible to prevent the amount of heating heat from being concentrated on the inlet side or the outlet side of the heat exchange medium with respect to the fuel cell, and to make the temperature of the entire power generation surface of the fuel cell uniform. The time required to warm up the entire power generation surface of the fuel cell to a predetermined temperature can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a temperature control device for a fuel cell according to one embodiment of the present invention, and is a diagram particularly illustrating a circulation path when a cooling medium is circulated in a forward direction.

FIG. 2 is a configuration diagram of a temperature control device for a fuel cell according to an embodiment of the present invention, and is a diagram particularly illustrating a circulation path when a cooling medium is circulated in a reverse direction.

FIG. 3 is a flowchart showing an operation of the temperature control device of the fuel cell, particularly an operation at the time of starting the fuel cell.

FIG. 4 is a flowchart showing an operation in a low-temperature start mode shown in FIG. 3;

FIG. 5 is a graph showing a change in temperature of a cooling medium.

FIG. 6 is a graph showing a change of a reversal flag for instructing reversal of a flowing direction of a cooling medium in a medium flow path.

FIG. 7 is a graph showing ON / OFF changes of an external heating operation for heating a cooling medium by a heating device.

FIG. 8 is a graph showing a change in ON / OFF of a power generation operation of the fuel cell.

FIG. 9 is a graph showing a temperature change of a cooling medium according to a modified example of the fuel cell starting method of the embodiment.

FIG. 10 is a graph showing a change of a reversal flag instructing a reversal of a flowing direction of a cooling medium in a medium flow path according to a modification of the fuel cell starting method of the embodiment.

FIG. 11 is a graph showing ON / OFF changes of an external heating operation for heating a cooling medium by a heating device according to a modification of the fuel cell starting method of the embodiment.

FIG. 12 is a graph showing a change in ON / OFF of a power generation operation of the fuel cell according to a modified example of the fuel cell starting method of the embodiment.

[Explanation of symbols]

 10, 20 Fuel cell system 10a, 20a Control unit (gas pressure control device) 12 Refrigerant tank (medium supply unit) 13 Circulation pump (medium supply unit) 14 Heating device (heating unit) 15 Refrigerant supply channel switching unit (medium supply) Path switching means) 21 medium flow path 22 supply port 23 discharge port

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Takashi Koyama 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 5H026 AA06 5H027 AA06 CC01 KK46 MM16

Claims (6)

[Claims] 1. A medium supply unit for supplying a heat exchange medium to a fuel cell, a heating unit for heating the heat exchange medium supplied from the medium supply unit, and the heat exchange medium heated by the heating unit By switching the supply destination of the heat exchange medium to one of the supply port and the discharge port of the medium flow path provided in the fuel cell, so that the flow direction of the heat exchange medium in the medium flow path can be reversed. A temperature control device for a fuel cell, comprising: a path switching unit. 2. A first step of heating a heat exchange medium to be supplied to the fuel cell at the time of starting the fuel cell; and supplying the heat exchange medium heated in the first step to the fuel exchange medium. A second step of switching the flow direction of the heat exchange medium in the medium flow path by switching to one of the supply port and the discharge port of the medium flow path provided in the battery. To start a fuel cell. 3. The fuel cell according to claim 2, wherein the first step and the second step are performed when the temperature of the fuel cell is equal to or lower than a predetermined first temperature. Method. 4. The method according to claim 2, further comprising a third step of starting power generation of the fuel cell when the temperature of the fuel cell is equal to or higher than a predetermined second temperature. The method for starting the fuel cell according to the above. 5. The method according to claim 2, wherein in the second step, a flow direction of the heat exchange medium in the medium flow path is reversed based on a temperature near the supply port and a temperature near the discharge port. 3. The method for starting a fuel cell according to item 2. 6. The flow direction of the heat exchange medium in the medium flow path based on the amount of heat supplied by the heat exchange medium supplied to one of the supply port and the discharge port. 3. The method for starting a fuel cell according to claim 2, wherein