JP2006216350A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a fuel cell to be efficiently operated in restarting it by rapidly completely discharging a cooling medium in the fuel cell by a method according to a condition of the fuel cell. <P>SOLUTION: Cooling medium-replacing manifolds 4a-4d independent of one another are installed in cooling medium passages 5a and 5b; cooling medium discharging cutoff valves mounted to the cooling medium-replacing manifolds 41-4d are opened in stopping the operation of the fuel cell to discharge the cooling medium; intake air introduction cutoff valves mounted to the manifolds 4a-4d are similarly opened to introduce compressed air; and the cooling medium is rapidly and completely discharged from the cooling medium passages 5a, 5b and 5c. In operation, the cooling medium discharging cutoff valves are closed so as not to discharge the cooling medium from the cooling medium-replacing manifolds 41-4d, and the intake air introduction cutoff valves are also closed so as not to introduce the compressed gas from the outside. A changeover three-way valve is installed between each manifold and each cutoff valve. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell system that quickly discharges a refrigerant in a fuel cell when the operation is stopped and starts up efficiently after the operation is resumed.

  In the start-up operation when the fuel cell is assumed to be used in an automobile, it is very important to reduce the heat capacity of each component of the fuel cell, particularly in starting the fuel cell from below freezing point. There is a concern that power generation cannot be generated due to a decrease in power generation performance due to a decrease in reaction speed at low temperatures or due to freezing of water necessary for cooling the fuel cell.

Therefore, for example, in addition to the cooling water (refrigerant) passage in the fuel cell, a cooling water circulation passage through which the cooling water circulated inside the fuel cell flows is configured outside the fuel cell, and the cooling water in the cooling water passage A fuel cell system with gas pressure extraction is disclosed.
JP-A-6-223855

  However, in the above invention, there is a possibility that the refrigerant may remain in the fuel cell stack depending on the posture of the vehicle at the time of stop, and that the start-up time delay and the start-up operation become impossible because the remaining refrigerant increases the heat capacity from the design estimate. There was a problem.

  Therefore, in order to solve such a problem, the present invention provides a fuel cell that can be efficiently operated at the time of restart by taking out the refrigerant in the refrigerant flow path completely and quickly by a method according to the situation of the fuel cell. For the purpose of provision.

In a fuel cell that generates power by stacking a plurality of unit cells through separators and supplying fuel gas and oxidant gas to each unit cell, a refrigerant flow path provided in each separator, and the refrigerant A refrigerant inlet manifold and a refrigerant outlet manifold capable of circulating and blocking refrigerant in the flow path, at least a pair of refrigerant replacement manifolds connected to the refrigerant flow path, and an external pressure gas supply section for each of the refrigerant replacement manifolds (Any pressure gas can be introduced), and a flow path switching mechanism that can be selectively connected to the refrigerant reservoir, and the pressure introduced from one refrigerant replacement manifold when the fuel cell is stopped. The gas in the refrigerant flow path is sent to the other refrigerant replacement manifold by gas, and the refrigerant in the fuel cell is replaced with gas.

  According to the present invention, the pressure gas is introduced into the refrigerant flow path from one refrigerant replacement manifold, and the refrigerant is discharged by the pressure gas so as to be pushed out from the other refrigerant replacement manifold. It can be discharged from the fuel cell.

  In addition, by forming the refrigerant replacement manifold independently from the refrigerant inlet manifold and the refrigerant outlet manifold, the refrigerant inlet manifold and the refrigerant outlet manifold are designed with priority given to performance during normal operation without taking into account residual refrigerant during refrigerant discharge. can do.

  A fuel cell system according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a sectional view of a unit cell 6 of a fuel cell 14 used in the fuel cell system of the present invention. The unit cell 6 includes a power generation film 6a having both an electrode catalyst and a gas diffusion function, a separator having a fuel gas channel 6b, and a separator having an oxidant gas channel 6c.

A separator having a fuel gas flow path 6b is provided on one side of the power generation membrane 6a, and a separator having an oxidant gas flow path 6c is provided on the other side. A recess (a portion between the oxidant gas flow path 6c and the fuel gas flow path 6b) on the outside (opposite side of the power generation film 6a) of each separator forms the refrigerant flow path 5 when the separators are stacked. .
Fuel gas is supplied to the fuel gas channel 6b from the outside, and air that has flowed through the intake hose 25 is also supplied to the oxidant gas channel 6c from the outside. The coolant channel 5 is circulated through the coolant channel 5 as described later.

  A refrigerant flow path 5, a refrigerant inlet manifold 1, a refrigerant outlet manifold 2, and refrigerant replacement manifolds 4a to 4d are formed on the outer surface of the separator shown in FIG.

  A flow path inlet side 5 a and a flow path outlet side 5 b are provided at both ends in the refrigerant flow path 5, the flow path inlet side 5 a is connected to the refrigerant inlet manifold 1, and the flow path outlet side 5 b is connected to the refrigerant outlet manifold 2. ing. As shown in FIG. 2, the cooling flow area 5c of the refrigerant flow path 5 has a larger cooling area than the flow path inlet side 5a and the flow path outlet side 5b, respectively.

  The cooling region 5c other than the flow channel inlet side 5a and the flow channel outlet side 5b is formed by arranging a plurality of elongated flow channels in parallel at a constant interval. The oxidant gas flow path 6c or the fuel gas flow path 6b enters the cooling region 5c at a constant interval. With this structure, it can be seen that the refrigerant flow path 5 is in contact with the oxidant gas flow path 6c of the unit cell 6 and the fuel gas flow path 6b of the unit cell 6 adjacent to the unit cell 6 as shown in FIG.

  The refrigerant inlet manifold 1 and the refrigerant outlet manifold 2 pass through the respective separators in the fuel cell 14 in the stacking direction, the refrigerant inlet manifold 1 communicates with an external refrigerant hose 24a, and the refrigerant outlet manifold 2 is an external refrigerant hose. It communicates with 24b.

  Refrigerant replacement manifolds 4a and 4b are provided in the vicinity of the flow path inlet side 5a and the flow path outlet side 5b of the refrigerant flow path 5, respectively, and similarly, refrigerant replacement manifolds 4c and 4d are provided at the lower end portion. The refrigerant replacement manifolds 4a to 4d communicate with the refrigerant flow path 5, respectively.

  FIG. 3 is a side view of the fuel cell 14 of the present invention. The fuel cell 14 includes a plurality of stacked unit cells 6, a current extraction plate 7, and end plates 8a and 8b.

  The outer side of the stacked unit cell 6 is sandwiched between a pair of current extraction plates 7 from both sides, and end plates 8 a and 8 b are stacked on the outer sides of the respective current extraction plates 7. Replacement ports 27a to 27d are connected to the outside of one end plate 8a, and replacement ports 27e to 27h are connected to the outside of the other end plate 8b. The replacement ports 27 a to 27 h are connected to the refrigerant replacement manifolds 4 a to 4 d that penetrate the fuel cell 14. Further, the replacement ports 27 a to 27 h are connected to the external pipe 9. That is, the refrigerant replacement manifolds 4a to 4d are connected to the external pipe 9 via the replacement ports 27a to 27h.

  FIG. 4 is a perspective view of the fuel cell 14 of the present invention.

  A replacement port 27a that communicates with the refrigerant replacement manifold 4a is provided on the outer surface of one end plate 8a, and a replacement port 27b that communicates with the refrigerant replacement manifold 4b, a replacement port 27c that communicates with the refrigerant replacement manifold 4c, A replacement port 27d communicating with the refrigerant replacement manifold 4d is provided.

  Similarly, on the outer surface of the other end plate 8b, a replacement port 27e that communicates with the refrigerant replacement manifold 4a, a replacement port 27f that communicates with the refrigerant replacement manifold 4b, and a replacement port 27g that communicates with the refrigerant replacement manifold 4c. And a replacement port 27h communicating with the refrigerant replacement manifold 4d.

  FIG. 5 is a schematic view of the configuration of the cooling system for the fuel cell 14 of the present invention. A refrigerant hose 24 a communicating with the refrigerant inlet manifold 1 and a refrigerant hose 24 b communicating with the refrigerant outlet manifold 2 are provided outside the fuel cell 14.

  The refrigerant hoses 24a and 24b are connected to the refrigerant cooling radiator 10, respectively. The refrigerant hose 24 a is connected to one side of the refrigerant cooling radiator 10 and the refrigerant inlet manifold 1 of the fuel cell 14, and the refrigerant hose 24 b is connected to the other side of the refrigerant cooling radiator 10 and the refrigerant outlet manifold 2 of the fuel cell 14. Connected. A refrigerant pump 12 is provided in the middle of the refrigerant hose 24a.

  A refrigerant cutoff valve 13a is provided between the refrigerant pump 12 provided in the refrigerant hose 24a and the fuel cell 14, and a refrigerant hose 24b between the refrigerant cooling radiator 10 and the fuel cell 14 is provided with the refrigerant cutoff valve 13b. It has been. Here, the refrigerant shut-off valves 13a and 13b are provided near the connection between the refrigerant hoses 24a and 24b and the fuel cell 14, respectively.

  The replacement ports 27a to 27d provided in the end plates 8a and 8b in the fuel cell 14 are connected to the intake / refrigerant switching three-way valves 23a to 23d via the pipe 9, respectively. Similarly, the replacement ports 27e to 27h are connected to the intake / refrigerant switching three-way valves 23e to 23h via the pipe 9, respectively. Here, a to h of the intake / refrigerant switching three-way valves 23a to 23h correspond to a to h of the replacement ports 27a to 27h.

  The intake / refrigerant switching three-way valves 23a to 23d switch and connect the replacement ports 27a to 27d to the refrigerant reservoir 11 side or the pressure accumulation tank 18 side. Similarly, the intake / refrigerant switching three-way valves 23e to 23h switch and connect the replacement ports 27e to 27h to the refrigerant reservoir 11 side or the accumulator tank 18 side.

  Between the intake / refrigerant switching three-way valves 23a-23d and the refrigerant reservoir 11, refrigerant discharge cutoff valves 22a-22d are provided, and between the intake / refrigerant switching three-way valves 23a-23d and the pressure accumulating tank 18 as a pressure gas supply unit. Are provided with intake intake shut-off valves 21a to 21d. Similarly, refrigerant discharge shut-off valves 22e to 22h are provided between the intake / refrigerant switching three-way valves 23e to 23h and the refrigerant reservoir 11, and an intake air intake shut-off is provided between the intake / refrigerant switching three-way valves 23e to 23h and the pressure accumulation tank 18. 21e to 21h are provided.

  The intake air introduction cutoff valves 21a to 21h and the refrigerant discharge cutoff valves 22a to 22h correspond to a to h of the replacement ports 27a to 27h, respectively.

  A pressure accumulation tank 18 that also serves as a supply source of the oxidant gas is provided with a pressure sensor 19, and is connected to an air compressor 17 provided with an intake filter 16.

  The air that has passed through the intake filter 16 is compressed by the air compressor 17 and sent to the pressure accumulation tank 18. The pressure sensor 19 can detect the pressure of the air in the pressure accumulation tank 18.

  An intake hose 25 is connected to the lower part of the accumulator tank, and the accumulator tank 18 is connected to a manifold for introducing an oxidant gas (not shown) communicating with the oxidant gas flow path 6c of the fuel cell 14 via the intake hose 25. is doing. Air is supplied as an oxidant gas from the pressure accumulation tank 18 during normal operation of the fuel cell 14.

  The outlet of the manifold for discharging the oxidant gas that communicates with the oxidant gas flow path 6 c of the fuel cell 14 is connected to the external off-gas exhaust pipe 26.

  The intake hose 25 and the off-gas exhaust pipe 26 are provided with oxidant gas valves 20a and 20b in the vicinity of the fuel cell 14, respectively.

  Below the refrigerant reservoir 11 and the refrigerant cooling radiator 10 are connected by a radiator flow path 10a. When the refrigerant is reduced among the refrigerant cooling radiator 10, the fuel cell 14, and the refrigerant hoses 24a and 24b, the refrigerant is automatically replenished from the refrigerant reservoir 11, and the refrigerant is expanded when the refrigerant expands due to the temperature rise of the fuel cell 14. The structure is such that it can be discharged to the refrigerant reservoir 11. That is, the refrigerant reservoir 11 has a role of a reservoir tank.

  The fuel cell 14 is provided with an inclination angle sensor 15 in order to detect the inclination angle of the fuel cell 14. The inclination angle sensor 15 can detect the inclination of the fuel cell 14 with respect to the front-rear direction and the inclination with respect to the left-right direction.

  FIG. 6 shows the heights of the replacement ports 27a to 27h with respect to the water level 28 when the fuel cell 14 is tilted back and forth when the fuel cell 14 of the present invention is mounted on a vehicle. FIG. 7 shows the heights of the replacement ports 27a to 27h with respect to the water level 28 when the fuel cell 14 is tilted back and forth from the state of FIG.

  FIG. 8 shows the heights of the replacement ports 27a to 27h with respect to the water level 28 when the fuel cell 14 is tilted left and right when the fuel cell 14 of the present invention is mounted on a vehicle. FIG. 9 shows the heights of the replacement ports 27a to 27h with respect to the water level 28 when the fuel cell 14 is tilted to the left and right with respect to the state of FIG.

  Next, the operation of the first embodiment of the present invention will be described.

  The operation during normal operation will be described with reference to FIGS. First, the air that has passed through the intake filter 16 and is sent to the air compressor 17 is sent to the pressure accumulating tank 18 after being compressed. The air in the pressure accumulating tank 18 flows through the intake hose 25 and is sent to the oxidant gas flow path 6c from the manifold through which the oxidant gas of the fuel cell 14 flows. Fuel gas is supplied from the outside to the manifold through which the fuel gas flows and is sent to the fuel gas flow path 6b. The electrons generated between the fuel gas flow path 6b and the power generation film 1 in each unit cell 6 due to the electrochemical reaction between the fuel gas and the oxidant gas are taken out from the current extraction plate 7, whereby the fuel cell 14 Power generation is performed.

  In order to suppress an increase in temperature in each unit cell 6 during normal operation of the fuel cell 14, cooling water as a refrigerant is circulated through the refrigerant flow path 5 of the separator.

  The refrigerant flows through the refrigerant hose 24 a by the action of the refrigerant pump 12, circulates through the fuel cell 14, circulates through the refrigerant hose 24 b, and circulates to the refrigerant cooling radiator 10. The refrigerant shut-off valves 13a and 13b are opened.

  The refrigerant supplied to the fuel cell 14 enters the refrigerant inlet manifold 1 of the separator, flows through the flow path inlet side 5a, the refrigerant flow path 5 and the flow path outlet side 5b, and is discharged from the refrigerant outlet manifold 2 to the outside. .

  The refrigerant cools the power generation film 6a, the fuel gas flow path 6b, and the oxidant gas flow path 6c that are in contact with the refrigerant flow path 5.

  At this time, the refrigerant discharge shut-off valves 22a to 22h are closed so that the refrigerant is not discharged from the refrigerant replacement manifolds 4a to 4d connected to the refrigerant flow path 5, and gas is externally supplied to the refrigerant replacement manifolds 4a to 4d. The intake intake shutoff valves 21a to 21h are closed so as not to enter.

  When the lower end of the refrigerant reservoir 11 and the upper end of the refrigerant cooling radiator 10 are connected by the radiator flow path 10a, and the refrigerant decreases in the cooling system between the refrigerant cooling radiator 10 and the fuel cell 14, the refrigerant is automatically The refrigerant is replenished to the refrigerant cooling radiator 10 from the storage unit 11, and the refrigerant is discharged to the refrigerant storage unit 11 when the refrigerant expands due to a temperature rise.

  Next, a system for extracting the refrigerant from the fuel cell 14 when the operation of the fuel cell 14 is stopped will be described.

  First, the vehicle stops at a flat place, and there is no load or the like, and the attitude of the fuel cell 14 does not tilt within a certain threshold as judged from the output of the inclination angle sensor 15 provided in the fuel cell 14. The cooling system will be described.

  First, the cooling pump 12 is stopped and the refrigerant cutoff valves 13a and 13b outside the fuel cell 14 are closed. As a result, the refrigerant can be divided into the amount remaining in the fuel cell 14 and the amount remaining in the other cooling system. When the operation of the fuel cell 14 is stopped, the supply of fuel gas and oxidant gas to each unit cell 6 is stopped.

  Here, the air compressor 17 is driven, and the air sent from the intake filter 16 is made high pressure and sent to the pressure accumulating tank. When the pressure sensor 19 detects that the pressure in the pressure accumulating tank 18 has become a predetermined value or more, the operation of the air compressor 17 is stopped.

  Replacement ports 27a, 27b, 27e, 27f corresponding to the refrigerant replacement manifolds 4a, 4b provided at the upper end of the refrigerant flow path 5, and a refrigerant replacement manifold 4c provided at the lower end of the refrigerant flow path 5, Replacement ports 27c, 27d, 27g, and 27h corresponding to 4d are separately used for gas introduction and refrigerant discharge.

  First, in order to send air from the upper end of the refrigerant flow path 5, the intake / refrigerant switching three-way valves 23a, 23b, 23e, and 23f corresponding to the replacement ports 27a, 27b, 27e, and 27f are switched and connected to the pressure accumulation tank 18 side. The intake intake shut-off valves 21a, 21b, 21e, and 21f are opened.

  As a result, the refrigerant replacement manifolds 4 a and 4 b inside the fuel cell 14 are connected to the pressure accumulation tank 18 via the replacement ports 27 a, 27 b, 27 e and 27 f and the pipe 9.

  On the other hand, the intake / refrigerant switching three-way valves 23c, 23d, 23g, and 23h corresponding to the replacement ports 27c, 27d, 27g, and 27h are switched and connected to the refrigerant reservoir 11, and the refrigerant discharge cutoff valves 22c, 22d, 22g, and 22h are opened. To do.

  By this action, the refrigerant replacement manifolds 4c, 4d inside the fuel cell 14 are connected to the refrigerant storage unit 11 via the replacement ports 27c, 27d, 27g, 27h.

  At this time, the refrigerant discharge cutoff valves 22a, 22b, 22e, and 22f are closed, and the intake intake cutoff valves 21c, 21d, 21g, and 21h are closed.

  Moreover, the supply of air from the outside and the discharge of air to the outside are stopped by closing the oxidant gas valves 20a and 20b.

  Air is sent from the pressure accumulating tank 18 to the replacement ports 27a, 27b, 27e, and 27f, and air is supplied from both sides of the refrigerant replacement manifolds 4a and 4b provided at the upper end of the refrigerant flow path 5. With this supplied air, the refrigerant is pushed out from the refrigerant replacement manifolds 4c, 4d at the lower end of the refrigerant flow path 5, and discharged from the replacement ports 27c, 27d, 27g, 27h to the refrigerant storage unit 11. As the amount of refrigerant in the refrigerant flow path 5 decreases, the air pressure in the pressure accumulating portion 18 also decreases. The residual amount of the refrigerant in the refrigerant flow path 5 can be known by the decrease in the air pressure inside the pressure accumulating tank 18.

  Here, when the pressure detected by the pressure sensor 19 provided in the pressure accumulating tank 18 is reduced to a predetermined value, it can be determined that the refrigerant has been completely discharged from the refrigerant flow path 5. The introduction shutoff valves 21a to 21h and the refrigerant discharge shutoff valves 22a to 22h are closed to finish the refrigerant discharge operation of the fuel cell 14.

  Next, when the refrigerant is reintroduced when the operation of the fuel cell 14 is resumed, the intake introduction cutoff valves 21a to 21h are all closed, and the refrigerant discharge cutoff valves 22a to 22h are fully opened. Further, the refrigerant cutoff valve 13a is opened and the refrigerant cutoff valve 13b is closed. In this state, air substituted for the refrigerant flows through the refrigerant flow path 5 of the fuel cell 14.

  When the refrigerant pump 12 is driven, the refrigerant is introduced from the refrigerant inlet manifold 1 into the refrigerant flow path 5, and the air accumulated in the refrigerant flow path 5 is pushed out from the refrigerant replacement manifolds 4a to 4d.

  The air is sent from the refrigerant replacement manifolds 4a to 4d to the refrigerant storage unit 11 via the replacement ports 27a to 27h. This exhausting operation is continued until all the air in the refrigerant flow path 5 is exhausted to the outside via the refrigerant reservoir 11. However, even when the refrigerant flow path 5 completely replaces the refrigerant, that is, when the refrigerant is reintroduced, bubbles remain in the refrigerant.

  In order to remove bubbles present in the refrigerant, the refrigerant pump 12 continuously circulates the refrigerant for a while. Bubbles in the refrigerant are separated by the refrigerant reservoir 11, and the bubbles in the refrigerant circulated from the radiator flow path 10a below the refrigerant cooling radiator 10 can be completely removed.

  Next, the operation of the refrigerant discharge system of the present invention when the fuel cell 14 is tilted back and forth or right and left when the vehicle is stopped will be described with reference to FIGS. 2 and 5 to 9.

  The fuel cell 14 will be described separately when it is tilted back and forth as shown in FIGS. 6 and 7 or tilted left and right as shown in FIGS. Here, the water level 28 is exemplarily shown in FIGS.

  When the operation of the fuel cell 14 is stopped, first, the inclination angle sensor 15 provided in the fuel cell 14 determines whether the inclination angle of the fuel cell 14 is the front-rear or left-right inclination.

  The inclination of the fuel cell 14 is detected by the output of the inclination angle sensor 15, and here, the case where the fuel cell 14 is inclined forward and backward as shown in FIG. 6 will be described.

  When the fuel cell 14 is tilted back and forth as shown in FIG. 6, the relationship between the replacement ports 27a to 27h and the water level changes as the refrigerant is discharged.

  First, the replacement ports 27a to 27h are the replacement ports 27e and 27f in the descending order of positions, then 27a and 27b, 27g and 27h, and 27c and 27d. The relationship between the angle detected by the inclination angle sensor 15 and the height of the replacement ports 27a to 27h at that time is detected in advance.

  Next, immediately after the operation of the fuel cell 14 is stopped, the replacement ports 27e and 27f are higher than the water level based on the inclination angle sensor 15, and the other replacement ports 27a, 27b, 27c, 27d, 27g, and 27h are the water level. Make sure it ’s lower.

  The intake / refrigerant switching three-way valves 23e and 23f corresponding to the replacement ports 27e and 27f at the highest position among the replacement ports 27a to 27h are switched and connected to the pressure accumulation tank 18 side. The other intake / refrigerant switching three-way valves 23a, 23b, 23c, 23d, 23g, and 23h are switched and connected to the refrigerant reservoir 11 side.

  The intake intake cutoff valves 21e and 21f are opened, and the other intake introduction cutoff valves 21a, 21b, 21c, 21d, 21g and 21h are closed.

  At the same time, the refrigerant discharge cutoff valves 22a, 22b, 22c, 22d, 22g and 22h are opened, and 22e and 22f are closed.

  Next, the oxidant gas valves 20a and 20b are closed. By this action, air flows from the pressure accumulation tank 18 to the replacement ports 27e and 27f, and air is supplied to the refrigerant flow path 5 from the upper side of the inclination of the refrigerant replacement manifolds 4a and 4b. Due to the pressure of the air sent to the refrigerant flow path 5, the refrigerant flows from the lower side of the refrigerant replacement manifolds 4a and 4b at the lower end of the refrigerant flow path 5 and from both sides of the refrigerant replacement manifolds 4c and 4d. Pushed out. Then, the refrigerant is discharged from the replacement ports 27 a, 27 b, 27 c, 27 d, 27 g, and 27 h and circulated to the refrigerant storage unit 11.

  After the above action, the air pressure in the pressure accumulating tank 18 is measured by the pressure sensor 19, and it is detected that the water level of the refrigerant in the refrigerant flow path 5 is lowered due to the decrease in the air pressure.

  Based on the detection value of the pressure sensor 19, the water level in the fuel cell 14 is lowered, the water level is lower than the replacement ports 27a and 27b, and the refrigerant replacement manifold 4a corresponding to the replacement ports 27a and 27b, It is determined that the refrigerant is completely discharged from 4b. This determination can be accurately derived from the relationship between the water level, the inclination angle of the inclination angle sensor 15, the arrangement of the replacement ports 27 a to 27 h, and the output of the pressure sensor 19, from the experimental results obtained in advance.

  At this time, the intake / refrigerant switching three-way valves 23a and 23b are switched and connected from the refrigerant reservoir 11 side to the pressure accumulation tank 18 side. The refrigerant discharge cutoff valves 22a and 22b are closed, and the intake introduction cutoff valves 21a and 21b are opened. By this action, the replacement ports 27a and 27b are connected to the pressure accumulating tank 18, and air is supplied to the fuel cell 14 also from the replacement ports 27a and 27b.

  After flowing through the replacement ports 27a, 27b, 27e, 27f, air flows from both sides of the refrigerant replacement manifolds 4a, 4b to the refrigerant flow path 5, and from both sides of the refrigerant replacement manifolds 4c, 4d, that is, the replacement ports 27c, The refrigerant is circulated from 27d, 27g, and 27h to the refrigerant reservoir 11.

  Further, when the pressure sensor 19 detects that the water level in the refrigerant flow path 5 falls below the replacement ports 27g and 27h, the intake / refrigerant switching three-way valves 23g and 23h are switched and connected from the refrigerant reservoir 11 to the pressure accumulation tank 18. At the same time, the refrigerant discharge cutoff valves 22g and 22h are closed, and the intake intake cutoff valves 21g and 21h are opened.

  By this action, the replacement ports 27g and 27h are connected to the pressure accumulating tank 18, and air is supplied to the fuel cell 14 also from the replacement ports 27g and 27h.

  Air from the replacement ports 27a, 27b, 27e, 27f, 27g, and 27h is sent to the refrigerant flow path 5 from both sides of the refrigerant replacement manifolds 4a and 4b and from above the inclined sides of the refrigerant replacement manifolds 4c and 4d. The refrigerant is discharged to the refrigerant storage part 11 from the inclined lower side of the replacement manifolds 4c, 4d.

  When the detection value of the pressure sensor 19 reaches a predetermined value, the above operation is terminated.

  By the way, even when the fuel cell 14 is tilted back and forth as shown in FIG. 7, it operates in the same procedure as when it is tilted back and forth as shown in FIG.

  At this time, the replacement ports 27e and 27f are at the highest positions at the heights of the replacement ports 27a to 27h, and the replacement ports 27g and 27h, 27a and 27b, and 27c and 27d are in the lower positions in this order. This is derived from the relationship between the arrangement of the sensor 15 and the replacement ports 27a to 27h.

  Hereinafter, the refrigerant is discharged in the same procedure as when the fuel cell 14 is tilted back and forth as shown in FIG.

  Next, a description will be given of the case where the vehicle is tilted left and right as shown in FIGS. 8 and 9, that is, the fuel cell 14 is tilted left and right. First, the case where the fuel cell 14 is tilted left and right as shown in FIG. 8 will be described.

  Based on the detection of the inclination angle of the fuel cell 14 from the inclination angle sensor 15, the order of the heights of the replacement ports 27a to 27h from the uppermost end (or the lowermost end) is previously grasped in the same manner as the previous time. Among the replacement ports 27a to 27h, the replacement ports 27b and 27f are at the highest position, and the replacement ports 27a and 27e, 27d and 27h, and 27c and 27g are at the lower positions in this order.

  Among the replacement ports 27a to 27h, the intake / refrigerant switching three-way valves 23b and 23f corresponding to the replacement ports 27b and 27f at the highest position are switched and connected to the pressure accumulation tank 18 side.

  The other intake / refrigerant switching three-way valves 23a, 23c, 23d, 23e, 23g, and 23h are switched and connected to the refrigerant storage unit 11.

  At the same time, the intake intake cutoff valves 21b and 21f are opened, and the other intake introduction cutoff valves 21a, 21c, 21d, 21e, 21g and 21h are closed.

  At the same time, the refrigerant discharge cutoff valves 22b and 22f are closed, and the other refrigerant discharge cutoff valves 22a, 22c, 22d, 22e, 22g and 22h are opened.

  The refrigerant in the refrigerant flow path 5 is pushed out from both sides of the refrigerant replacement manifolds 4a, 4c, and 4d by the pressure of the supplied air. The extruded refrigerant is circulated from the replacement ports 27a, 27e, 27c, 27d, 27g, and 27h to the storage unit 11 through the pipe 9.

  From the output of the pressure sensor 19, the water level in the fuel cell 14 is lowered, the water level is lower than the replacement ports 27a and 27e, and the refrigerant is completely discharged from the refrigerant replacement manifold 4a corresponding to the replacement ports 27a and 27e. When it is determined that the state has been reached, the intake / refrigerant switching three-way valves 23a and 23e corresponding to the replacement ports 27a and 27e are switched and connected to the pressure accumulation tank 18 side. At the same time, the intake intake cutoff valves 21a and 21e are opened, and the refrigerant discharge cutoff valves 22a and 22e are closed. Thus, air is also supplied from the replacement ports 27a and 27e to the refrigerant flow path 5 from both sides of the refrigerant replacement manifolds 4a and 4b.

  When the water level is further lowered and lower than the replacement ports 27d and 27h and higher than the replacement ports 27c and 27g by the pressure of the air sent in, the intake / refrigerant switching three-way valves 23d and 23h are moved from the refrigerant reservoir 11 to the pressure accumulation tank 18. Switch to the side. At the same time, the refrigerant discharge cutoff valves 22d and 22h are closed, and the intake introduction cutoff valves 21d and 21h are opened.

  By this action, air is also sent into the refrigerant flow path 5 from the replacement ports 27d and 27h. With the air sent in, the refrigerant remaining in the refrigerant flow path 5 can be discharged to the refrigerant reservoir 11.

  Even when the fuel cell 14 is tilted left and right as shown in FIG. 9, the refrigerant is discharged from the refrigerant flow path 5 by performing the above-described action in the same manner.

  In the case where the refrigerant is reintroduced after the refrigerant in the fuel cell 14 is extracted, the refrigerant is introduced by the same action as when the fuel cell 14 is not inclined, and bubbles in the refrigerant are removed.

  In addition, the control of the above-described refrigerant discharge and reinjection is performed by a controller (not shown) that controls the intake / refrigerant switching three-way valves 23a to 23h, the intake introduction cutoff valves 21a to 21h, the refrigerant discharge cutoff valves 22a to 22h, and the refrigerant cutoff valves 13a and 13b. This is automatically performed based on the tilt angle sensor 15.

  Note that the refrigerant can also be removed from the refrigerant flow path 5 of the fuel cell 14 in the same manner as described above while continuously sending air from the air compressor 17 to the pressure accumulation tank 18 at a constant pressure.

  Here, taking out the refrigerant from the refrigerant flow path 5 when the fuel cell 14 is tilted back and forth as shown in FIG. 6 will be described as an example.

  When air is continuously sent from the pressure accumulation tank 18 to the replacement ports 27e and 27f of the fuel cell 14, air is supplied to the refrigerant flow path 5 from one side above the refrigerant replacement manifolds 4a and 4b. The refrigerant is discharged from one side below the refrigerant replacement manifolds 4a and 4b and from both sides of the refrigerant replacement manifolds 4c and 4d by the air that is sent in and the opening of the replacement ports 27a, 27b, 27c, 27d, 27g, and 27h. The

  When the coolant level in the fuel cell 14 is lowered from the replacement ports 27a and 27b and the refrigerant is completely removed from the refrigerant replacement manifolds 4a and 4b, air is sent to the pipe 9 through the replacement ports 27a and 26b. . The moment the air is sent to the replacement ports 27a and 27b, the pressure in the refrigerant flow path 5 slightly decreases.

  By determining the slightly reduced pressure, the intake / refrigerant switching three-way valves 23a and 23b corresponding to the replacement ports 27a and 27b are switched and connected to the pressure accumulation tank 18. Air is also sent from the accumulator tank 18 to the replacement ports 27a and 27b. Therefore, when the refrigerant is completely discharged from the refrigerant flow path 5, the pressure in the refrigerant flow path 5 at that time becomes a constant pressure and does not change.

  Even by the determination of the water level by the pressure accumulating tank 18, the pressure sensor 19, and the air compressor 17, the refrigerant replacement manifolds 4a to 4h can be accurately used for refrigerant discharge or air introduction depending on the situation. The refrigerant can be completely discharged from the flow path 5.

  Next, the effect | action of the bubble removal of the refrigerant | coolant from the refrigerant | coolant flow path 5 at the time of normal operation is demonstrated.

  In general, since air bubbles accumulate in a high place, the replacement ports 27a to 27h at the highest position detected from the inclination sensor 15 during the air bubble removal operation are determined to eliminate air bubbles in the refrigerant. For example, when the replacement port 27a is at the highest position, the intake / refrigerant switching three-way valve 23a is switched to the refrigerant reservoir 11 side, the refrigerant discharge shut-off valve 22a is opened, and refrigerant other than the normal refrigerant flow path 5 The air bubbles in the refrigerant can be removed together with the refrigerant flowing through the replacement port 27a.

  Carry out this operation at a certain time, and switch to normal operation after completion. By this action, bubbles that could not be completely removed when the refrigerant is reintroduced as described below can be completely removed from the refrigerant.

  The effect of 1st Embodiment of this invention is demonstrated.

  In the fuel cell 14 of the present invention, the refrigerant flow path 5 is provided with a refrigerant inlet manifold and a refrigerant outlet manifold capable of circulating and blocking the refrigerant, and at least a pair of refrigerant replacement manifolds 4a to 4d connected to the refrigerant flow path 5, respectively. The refrigerant replacement manifolds 4a to 4d were connected to the external pressure gas storage pressure tank 18 and the intake / refrigerant switching three-way valves 23a to 23h, which can be selectively connected to the refrigerant reservoir 11, respectively. With this configuration, the refrigerant replacement manifolds 4a to 4d can be switched and used for refrigerant discharge or gas introduction during refrigerant discharge.

  When the operation of the fuel cell 14 is stopped, the refrigerant in the refrigerant flow path 5 is sent to the other refrigerant replacement manifolds 4a to 4d by the air introduced from one of the refrigerant replacement manifolds 4a to 4d. Therefore, the refrigerant in the refrigerant flow path 5 can be completely and quickly removed.

  Since one of the refrigerant replacement manifolds 4a to 4d is connected to the upper part of the refrigerant flow path 5, and the other refrigerant replacement manifold 4a to 4d is connected to the lower part of the refrigerant flow path 5, the refrigerant flow path. Since air is fed from above 5 and the refrigerant is discharged from below the refrigerant flow path 5, the refrigerant in the refrigerant flow path 5 is replaced with gas, and the refrigerant is completely discharged.

  Further, in the configuration of the fuel cell 14 of the present invention, the refrigerant replacement manifolds 4a to 4d are made independent of the manifold through which the fuel gas flows and the manifold through which the oxidant gas flows, the refrigerant inlet manifold 1 and the refrigerant outlet manifold 2. Since it is connected to the flow path 5, the arrangement of the refrigerant flow path 5 and the refrigerant inlet manifold 1 and the refrigerant outlet manifold 2 that affect the performance during operation of the fuel cell 14 is not considered in consideration of the remaining amount when the refrigerant is discharged. The cooling performance can be prioritized.

  When the refrigerant flow path 5 is refilled with the refrigerant, the refrigerant is introduced from the refrigerant inlet manifold 1, the discharge of the refrigerant from the refrigerant outlet manifold 2 is blocked, and the refrigerant replacement manifolds 4 a to 4 are inserted into the refrigerant flow path 5. Since the accumulated gas is discharged, it is possible to completely remove bubbles remaining in the refrigerant flow path 5 having a complicated shape, and there is no local heat spot in the fuel cell 14 due to bubble clogging. The factors that adversely affect the life of the fuel cell 14 can be removed.

  During operation of the fuel cell 14, the refrigerant is introduced into the refrigerant flow path 5 from the refrigerant inlet manifold 1 and discharged from the refrigerant outlet manifold 2, while the refrigerant replacement manifolds 4 a to 4 d at the upper part of the refrigerant flow path 5 are placed in the refrigerant reservoir. By connecting with No. 11, the bubbles contained in the refrigerant were excluded. Since the refrigerant replacement manifolds 4a to 4d used at this time correspond to the replacement ports 27a to 27h at the highest position determined from the inclination angle sensor 16, the replacement ports 27a to 27h are operated during the operation of the fuel cell 14. Even if the height of the refrigerant changes, the refrigerant is discharged from one side above the refrigerant replacement manifolds 4a to 4d corresponding to the replacement ports 27a to 27h which are always at the highest position, and the bubbles contained in the refrigerant are surely removed. It becomes possible to do.

  At least two refrigerant replacement manifolds 4 a to 4 d are provided at different positions in the upper part of the refrigerant flow path 5, and at least two refrigerant replacement manifolds 4 a to 4 d are similarly provided at different positions in the lower part of the refrigerant flow path 5. Even if the fuel cell 14 is tilted when the refrigerant is discharged from the fuel cell 14 by including the tilt angle sensor 15 that detects the tilt of the fuel cell 14 before and after, left and right, or a combined tilt of the front and rear and left and right, the tilt angle Judging from the detection value of the sensor 15, air can be introduced from the replacement ports 27a to 27h at the highest position, and the refrigerant can be discharged from the other replacement ports 27a to 27h. Alternatively, the refrigerant in the refrigerant flow path 5 can be quickly and reliably discharged even when it is tilted back and forth and left and right.

  When the fuel cell 14 is tilted as described above by detecting in advance the relationship between the tilt angle sensor 15, the coolant level, the pressure accumulation tank 18, and the height positions of the replacement ports 27a to 27h, It is possible to accurately determine the relationship between the replacement ports 27a to 27h that change with time from the detection value of the inclination angle sensor 15 and the water level. As a result, the intake / refrigerant switching three-way valves 23a to 23h are connected to the replacement ports 27a to 27h that are higher than the coolant level in the refrigerant flow path 5, and the replacement ports 27a to 27a that are always higher than the water level are connected. Air can be introduced from 27h, and the refrigerant can be discharged from the replacement ports 27a to 27h at a position lower than the water level. Therefore, even when the fuel cell 14 is tilted back and forth or left and right or front and rear left and right, the refrigerant flow path 5 Since the refrigerant remaining in the refrigerant is discharged to the outside so as to push downward from above, the refrigerant remaining in the refrigerant flow path 5 can be completely removed quickly.

  Since the refrigerant pump 12 is provided in the refrigerant hose 24a, the refrigerant can be circulated from the refrigerant reservoir 11 to the refrigerant inlet manifold 1, the refrigerant flow path 5, and the refrigerant outlet manifold 2. The refrigerant can be optionally circulated in the fuel cell 14 by the configuration and action of the refrigerant pump 12.

  Since the refrigerant reservoir 11 is a reservoir tank, it is possible to discharge the refrigerant to the refrigerant reservoir 11 when the refrigerant expands during normal operation, and to introduce the refrigerant when the fuel cell 14 runs out of refrigerant.

  It goes without saying that the present invention is not limited to the above-described embodiments, and includes various modifications and improvements that can be made within the scope of the technical idea.

  It can be used for a fuel cell vehicle that runs on a fuel cell.

It is the schematic in the unit cell of the fuel cell of 1st Embodiment of this invention. It is the schematic of the separator of the fuel cell of 1st Embodiment of this invention. It is the schematic of the side surface of the fuel cell of 1st Embodiment of this invention. It is the schematic of the perspective view of the fuel cell of 1st Embodiment of this invention. Some separators and cooling manifolds are shown. It is the schematic of the cooling system of the fuel cell of 1st Embodiment of this invention. It is the schematic of the side surface of the fuel cell of 1st Embodiment of this invention. It is the schematic of the side surface of the fuel cell of 1st Embodiment of this invention. It is the schematic of the front of the fuel cell of 1st Embodiment of this invention. It is the schematic of the front of the fuel cell of 1st Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigerant inlet manifold 2 Refrigerant outlet manifold 4a-4d Manifold for refrigerant replacement 5 Refrigerant flow path 5a Flow path inlet side 5 Flow path outlet side 5c Cooling flow path 6a Power generation film 6b Fuel gas flow path 6c Oxidant gas flow path 7 Current extraction Plate 8a End plate 8b End plate 9 Piping 10 Refrigerant cooling radiator 10a Radiator flow path 11 Refrigerant reservoir 12 Refrigerant pump 13a Refrigerant shutoff valve 13b Refrigerant shutoff valve 14 Fuel cell 15 Inclination angle sensor 16 Intake filter 17 Air compressor 18 Accumulation tank 19 Pressure sensor 20a Oxidant gas valve 20b Oxidant gas valve 21a-21h Intake introduction shutoff valve 22a-22h Refrigerant discharge shutoff valve 23a-23h Intake / refrigerant switching three-way valve 24a Refrigerant hose 24b Refrigerant hose 25 Intake hose 26 Off gas exhaust pipe 27a ~ 27h Replacement port 2 Water level

Claims (12)

In a fuel cell in which a plurality of unit cells are stacked via separators, and power is generated by supplying fuel gas and oxidant gas to each unit cell.
A refrigerant flow path provided in each separator;
A refrigerant inlet manifold and a refrigerant outlet manifold capable of circulating and blocking the refrigerant in the refrigerant flow path;
At least a pair of refrigerant replacement manifolds connected to the refrigerant flow path;
A flow path switching mechanism capable of selectively connecting each of the refrigerant replacement manifolds to an external pressure gas supply unit and a refrigerant storage unit,
A fuel cell in which the refrigerant in the refrigerant channel is sent to the other refrigerant replacement manifold by the pressure gas introduced from one refrigerant replacement manifold when the fuel cell is stopped, and the refrigerant in the fuel cell is replaced with the gas. system. 2. The fuel cell system according to claim 1, wherein the one refrigerant replacement manifold is connected to an upper part of the refrigerant flow path, and the other refrigerant replacement manifold is connected to a lower part thereof.   3. The fuel cell system according to claim 2, wherein when the refrigerant is discharged from the refrigerant flow path, a pressure gas is introduced from the upper refrigerant replacement manifold and the refrigerant is discharged from the lower refrigerant replacement manifold.   When the refrigerant is refilled into the refrigerant flow path, the refrigerant is introduced from the refrigerant inlet manifold, the refrigerant discharge from the refrigerant outlet manifold is shut off, and the gas accumulated in the refrigerant flow path from the refrigerant replacement manifold is removed. The fuel cell system according to claim 2, wherein the fuel cell system is discharged.   During operation of the fuel cell, the refrigerant is introduced into the refrigerant flow path from the refrigerant inlet manifold and discharged from the refrigerant outlet manifold, while the upper refrigerant replacement manifold is communicated with the refrigerant reservoir so that The fuel cell system according to claim 2 or 3, wherein bubbles contained in the fuel cell are excluded. As the one refrigerant replacement manifold, at least two refrigerant replacement manifolds are connected at different positions in the upper part of the refrigerant flow path, and also as the other refrigerant replacement manifold, in different positions at the lower part of the refrigerant flow path. At least two refrigerant replacement manifolds are connected,
Means for detecting the inclination of the fuel cell;
When the refrigerant is discharged from the refrigerant flow path, the pressure gas is introduced from the uppermost refrigerant replacement manifold and the refrigerant is discharged from the lowermost refrigerant replacement manifold according to the inclination angle detected by the inclination detecting means. The fuel cell system according to claim 1, wherein   When the refrigerant is discharged from the refrigerant flow path, the pressure gas is introduced from the refrigerant replacement manifold located at the uppermost position by the inclination angle detected by the inclination detecting means. 6. The fuel cell system according to claim 5, wherein the pressurized gas is also introduced from a low refrigerant replacement manifold. The refrigerant replacement manifold is provided through the fuel cell in the stacking direction,
The refrigerant replacement manifold is configured to be selectively connectable to the external pressure gas supply unit and the refrigerant storage unit via the flow path switching mechanism at both ends thereof, respectively. 8. The fuel cell system according to any one of 7 above.   The fuel cell system according to any one of claims 1 to 8, wherein the pressure gas supply unit is a livestock pressure tank that stores compressed air as an oxidant gas supplied to the fuel cell. Means for detecting the gas pressure in the animal pressure tank;
The fuel cell system according to claim 9, wherein a discharge state of the refrigerant is estimated based on the detected pressure when the refrigerant is discharged from the refrigerant flow path.   The refrigerant inlet manifold and the refrigerant outlet manifold are connected to a radiator that cools the refrigerant through a circulation passage, and the circulation passage includes a pump that pumps the refrigerant to the refrigerant inlet manifold. The fuel cell system described in 1. The fuel cell system according to claim 11, wherein the refrigerant storage unit is a reservoir tank for refrigerant to be circulated in the circulation passage.