JP5332199B2 - Piping structure for fuel cell stack - Google Patents

Description

  The present invention relates to fuel cell stack piping, and more particularly to piping for supplying fluid such as fuel gas, oxidant gas, and cooling medium to the fuel cell stack.

  In recent years, hybrid vehicles that use both an engine and a motor as driving sources are becoming popular as environmentally friendly vehicles, and electric vehicles and fuel cell vehicles that use only motors as driving sources are also being studied for practical use. Development is underway. Among them, a fuel cell vehicle drives a motor with electric power taken out by an electrochemical reaction between a fuel gas in the fuel cell, for example, hydrogen and an oxidant gas, for example, oxygen. It is attracting attention as the ultimate eco car because only water is produced.

  The fuel cell is usually configured by stacking a plurality of fuel cell single cells each having a low generated voltage and connecting them in series with end plates sandwiched from both sides in the stacking direction. And the fuel cell heated by the heat generated by the above-mentioned electrochemical reaction through the pipe connected to the supply port formed in the end plate and the hydrogen as the fuel gas, the oxygen containing oxygen as the oxidant gas A cooling medium for cooling the cell, for example, LLC (Long Life Coolant) is supplied to the stack.

  Within the stack, each supply manifold for supplying fuel gas, oxidant gas and cooling medium to each fuel cell, and fuel gas, oxidant gas and cooling medium discharged from each fuel cell are placed outside the stack. Each discharge manifold for discharging to the center is provided penetrating in the cell stacking direction.

  Each fuel cell is supplied with hydrogen from a fuel gas supply manifold, and is supplied with oxygen-containing air from an oxidant gas supply manifold, and these hydrogen and oxygen are electrochemically passed through a solid polymer electrolyte membrane. By reacting, power is generated and water is generated. The electric power generated in each fuel cell is taken out through current collecting plates provided at both ends of the stack in the stacking direction.

  Waste hydrogen gas discharged from each fuel cell and waste air containing reaction product water are discharged out of the stack through the fuel gas discharge manifold and the oxidant gas discharge manifold. In addition, the cooling medium supplied from the cooling medium supply manifold to each fuel cell cools the cell heated by the heat generated by the reaction when passing through the fuel cell, and then the outside of the stack via the cooling medium discharge manifold. To be discharged.

  In the fuel cell stack as described above, a plurality of stacks having the same configuration may be arranged side by side so that the cell stacking directions are parallel to each other. For example, in Patent Document 1, four stacks are arranged at a matrix position, and fuel gas, oxidant gas, and cooling medium are supplied to each stack via a fuel supply / discharge member provided between the two stacks. As a result, the number of branch points and the distance from the branch point of the supply path and the discharge path fluid of the fuel gas and the like for each stack are completely the same, and the uniform distribution of the respective fluids is ensured. It is described that the performance of can be improved.

JP 2000-164236 A

  However, in a fuel cell stack in which a plurality of stacks having the same configuration are arranged side by side, when a fluid is distributed and supplied to each stack via a branch pipe branched from a fluid main pipe at a branch portion, the fuel cell stack is mounted. The above-mentioned branching part may not be arranged at the same distance from the fluid supply port of each stack due to the mounting position in the vehicle and the relationship with other vehicle components, etc. There is a problem of non-uniformity.

  Therefore, an object of the present invention is for a fuel cell stack that enables a uniform supply of fluid to each stack even when the branch portions where the branch pipe branches from the fluid main pipe cannot be arranged at an equal distance from each stack. To provide piping.

Piping for a fuel cell stack according to the present invention, each of the fuel cell stack comprising each configured first laminate is sandwiched between a stack of a plurality of fuel cells in the clamping member and the second stack side by side A pipe for supplying a fluid, which is a gas or a liquid, from the same side end in the cell stacking direction to the stacked body, and is branched from the main pipe through the branch portion, and the fluid of the first stacked body A first pipe connected to the supply port and a second pipe connected to the fluid supply port of the second stacked body, and the first pipe has a shorter channel length than the second pipe, and the first pipe. Is provided with a pressure loss part that causes a pressure loss for the fluid flowing inside ,
The first pipe includes a part to be cut, and the part to be cut is connected via a cylindrical member made of a material having a rigidity lower than that of the pipe material, and the pressure loss portion is a pipe end facing the part to be cut. The portion is constituted by a throttle part having a smaller cross-sectional area than the other part of the first pipe, or by a convex part protruding radially inward from the inner peripheral surface of the cylindrical member at the dividing location. than other portions of the first pipe is composed of smaller the throttle section the cross-sectional area, characterized in Rukoto.

In the fuel cell stack pipe according to the present invention, the fluid supplied to the second stacked body by the second pipe is a cooling medium, and branches from the second pipe to divert the cooling medium to the exhaust drain valve. You may include the 1st bypass piping to flow and the 2nd bypass piping which joins the cooling medium discharged from the exhaust drain valve to the 2nd piping .

In the fuel cell stack pipe according to the present invention, the first bypass pipe is fitted in a clamp portion fixed to a gas-liquid separator that separates reaction product water from waste fuel gas discharged from the fuel cell stack. May be supported .

  According to the fuel cell stack pipe according to the present invention, for the first and second pipes that branch from the main pipe via the branch portion, the first pipe has a shorter channel length than the second pipe and flows inside. By providing a pressure loss part that causes a pressure loss in the fluid, even if the branch part is not arranged at an equal distance from the fluid supply port of each stack, pressure is applied to the fluid flowing through the first pipe by the pressure loss part. By causing a loss, the pressure (ie, the flow rate) when reaching the fluid supply port of each stack can be made uniform, and as a result, the fluid can be equally distributed to each stack. Power generation operation with the same performance can be guaranteed.

  Further, if the first pipe is provided with a dividing portion and the dividing portion is connected via a cylindrical member made of a material having a rigidity lower than that of the piping material, the stack connecting portion at the end portion of the first piping and the first pipe are connected. The manufacturing dimensional error of the distance between the stack connecting portions at the ends of the two pipes can be absorbed or allowed by the connecting part by the tubular member, and the manufacturing of the fuel cell stack pipes becomes easy.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. In this description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating the understanding of the present invention, and can be appropriately changed according to the application, purpose, specification, and the like.

  FIG. 1 is a plan view of a fuel cell stack 1 to which fuel cell stack pipes 10, 12, and 14 according to an embodiment of the present invention are connected. At the end of the fuel cell stack 1, an air supply pipe 10 for supplying air containing oxygen as an oxidant gas, a hydrogen supply pipe 12 for supplying hydrogen as a fuel gas, and a cooling medium such as LLC A cooling medium supply pipe 14 is connected to supply.

  The fuel cell stack 1 includes a first stack 16 and a second stack 18. The first stack 16 is configured by stacking a plurality of fuel cells 20 in the thickness direction. The fuel battery cell 20 includes a solid polymer electrolyte membrane sandwiched between a fuel electrode layer and an oxidation electrode layer that are electrically conductive and air permeable, and a separator having a coolant channel through which a cooling medium flows. Arranged at least on one side. The second stack 18 also has the same configuration as the first stack 16.

  Inside the first stack 16, along the cell stacking direction indicated by arrow A, a hydrogen supply manifold 22a, a hydrogen discharge manifold 22b, an air supply manifold 24a, an air discharge manifold 24b, a refrigerant supply manifold 26a, and a refrigerant discharge manifold 26b is formed through each. In FIG. 1, the hydrogen supply manifold 22a and the air discharge manifold 24b, the air supply manifold 24a and the hydrogen discharge manifold 22b, and the refrigerant supply manifold 26a and the refrigerant discharge manifold 26b are shifted in the horizontal direction (left and right direction in FIG. 1), respectively. Although drawn, this is for ease of illustration and understanding, and since they are provided apart in the depth direction of FIG. 1 paper, they can be formed at positions that completely overlap in the plan view.

Similarly, the second stack 18, a hydrogen supply manifold 22a, a hydrogen discharge manifold 22b, an air supply manifold 24a, an air discharge manifold 24b, the coolant supply manifold 26a, and, although the coolant discharge manifold 26 b is formed, supply and The discharge is laterally opposite to the first stack 16 in the horizontal direction.

  The first stack 16 and the second stack 18 are arranged side by side in parallel along the cell stacking direction at a predetermined interval, and both ends of each of the stacks 16 and 18 are respectively a pair of current collectors (clamping members) 28a. 28b, insulating plates (clamping members) 30a, 30b, and end plates (clamping members) 32a, 32b. The end plates 32a and 32b are connected by a tension plate made of a belt-like member (not shown), and thereby a holding force for sandwiching the stacks 16 and 18 is applied.

  The first stack 16 and the pair of current collector plates 28a and 28b, the insulating plates 30a and 30b, and the end plates 32a and 32b sandwiching the first stack 16 in the present embodiment constitute the first laminate in the invention of the present application. The second stack 18 and the pair of current collecting plates 28a and 28b, the insulating plates 30a and 30b, and the end plates 32a and 32b sandwiching the second stack 18 in the embodiment constitute a second laminate in the present invention. In the present embodiment, the insulating plates 30a and 30b and the end plates 32a and 32b are configured as an integral member common to the first stack 16 and the second stack 18. However, the present invention is not limited to this, and the insulating plate and the end plate are not limited thereto. The plate may be configured to be separated from the first stack 16 and the second stack 18.

  Each one of the current collecting plate 28a, the insulating plate 30a, and the end plate 32a has through holes that constitute a part of the manifolds 22a, 22b, 24a, 24b, 26a, 26b of the first and second stacks 16, 18. The end portions of the manifolds 22a, 22b, 24a, 24b, 26a, and 26b are formed in the outer end surface of the end plate 32a.

  2 is a side view of the air supply pipe 10, and FIG. 3 is a partial cross-sectional view of the vicinity of the branch pipe of the air supply pipe 10 in FIG. The air supply pipe 10 includes a main pipe 40 to which air is supplied from an air supply machine (not shown), a substantially T-shaped branch pipe (branch portion) 42 connected to the main pipe 40 and bifurcated, and a branch pipe 42. Includes a first pipe 44 and a second pipe 46, one end of which is connected to each other. The main pipe 40, the first pipe 44, and the second pipe 46 are all formed of metal pipes, and are fixed by welding or the like in a state of being inserted into the branch pipe 42 as shown in FIG.

  A flange 50 having two mounting holes 48 is fixed to each other end of the first pipe 44 and the second pipe 46, and the flange 50 is fastened to the end plate 32a with bolts inserted into the mounting holes 48. By fixing, the air supply pipe 10 is attached to the fuel cell stack 1. As a result, the other end of the first pipe 44 is connected to the end of the air supply manifold 24 a of the first stack 16, and the other end of the second pipe 46 is connected to the end of the air supply manifold 24 a of the second stack 18. The

  As shown in FIG. 2, the first pipe 44 is set such that the flow path length L1 viewed in the horizontal direction from the center of the branch pipe 42 is shorter than the flow path length L2 of the second pipe 46. That is, the branch pipe 42 is located at an unequal distance with respect to the opening end of the air supply manifold 24 a of the first stack 16 and the opening end of the air supply manifold 24 a of the second stack 18. The second pipe 46 that is longer than the first pipe 44 is supported by a support member 52 that is fixed to the end plate 32a.

  The branch pipe 42 is formed by joining two halved parts manufactured by press-molding a metal plate by welding or the like in a state of being assembled. By configuring the branch pipe 42 with a press-molded product in this way, the number of manufacturing steps can be reduced and the cost can be reduced even when the metal tube is manufactured by cutting. Further, by being formed by press molding, the branch branches 43a and 43b divided into two branches can be formed so as to become an inner surface 43c that curves smoothly and branches. Thus, the pressure loss about the airflow distributed with the branch pipe 42 can be reduced by setting it as the smooth curved branch flow path which was not manufacturable by cutting.

  As shown in FIG. 3, the first pipe 44 includes a divided portion 54, and the divided portion 54 is connected to a tubular member made of a material having a lower rigidity than a metal material that is a pipe material, such as a rubber hose 56. It is connected. The rubber hose 56 is fixed to the first pipe 44 on both sides of the dividing portion 54 by hose clamps 58, 58 provided on the outer periphery of the hose. In this way, by providing the first pipe 44 with the dividing portion 54 and connecting the divided portion 54 with the rubber hose 56, the mounting hole 48 of the flange 50 at the end portion of the first pipe 44 and the end portion of the second pipe are provided. A manufacturing dimensional error of the distance L3 between the mounting hole 48 of a certain flange 50 can be absorbed or allowed by the connecting portion by the rubber hose 56, and the manufacturing of the fuel cell stack pipe 10 is facilitated.

  Each pipe end 44 a, 44 b facing the dividing portion 54 of the first pipe 44 is formed as a throttle part having a smaller cross-sectional area than other parts of the first pipe 44. The throttle portion functions as a pressure loss portion that causes a pressure loss in the air flowing in the pipe toward the first stack 16.

  Note that the hydrogen supply pipe 12 and the cooling medium supply pipe 14 also have the same configuration as the air supply pipe 10, and the hydrogen supply pipe 12 is connected to the fuel cell stack 1 in a state of being reversed left and right with respect to the air supply pipe 10. It is attached to.

  As described above, according to the fuel cell stack pipes 10, 12, and 14 of the present embodiment, the first pipe 44 is shorter than the second pipe 46 and causes a pressure loss in the air flowing inside. Since the pressure loss part is provided, the first pipe is formed by the pressure loss part even if the branch part 42 is not arranged at an equal distance from the supply inlet of each supply manifold 22a, 24a, 26a of each stack 16, 18. The pressure (ie, the flow rate) when reaching the fluid supply inlet of each of the stacks 16 and 18 can be made uniform by causing a pressure loss in the fluid such as air, hydrogen, and cooling medium flowing through The fluid can be equally distributed to the stacks 16 and 18, and the power generation operation with the same performance of the stacks 16 and 18 can be ensured.

  In the above embodiment, the pressure loss part of the first pipe 44 is configured as the throttle part of the pipe end. However, the pressure loss part of the present invention is not limited to this and may be of other forms. For example, as shown in FIG. 4, the throttle portion may be configured by a convex portion protruding in the hose central axis direction from the inner peripheral surface of the rubber hose 56 at the dividing portion 54 of the first pipe 44. Alternatively, although not shown, the throttle portion may be formed by deforming a part of the first pipe 44 so as to be slightly crushed, or the first pipe 44 may be formed in a curved shape in the flow path direction, and the second pipe 46 may be formed. Also, a large pressure loss may be generated.

  Next, a cooling medium supply pipe fixing structure will be described with reference to FIGS. FIG. 5 is a partial side view of the fuel cell system 2 including the fuel cell stack 1. As described above, air is supplied to the fuel cell stack 1 via the second pipe 46 of the air supply pipe 10 to the second stack 18, and the cooling medium is supplied via the second pipe 46 of the cooling medium supply pipe 14. The second stack 18 is supplied.

In this embodiment, a first bypass pipe 62 branched from the second cooling medium pipe 46 is provided. The first bypass pipe 62 is connected to the exhaust / drain valve 64. Cooling medium from the second pipe 46 for cooling medium has been diverted to the first bypass pipe 62, by flowing through the water discharge valve 64, to cool the exhaust drainage valve 64. The cooling medium discharged from the exhaust / drain valve 64 is joined to the cooling medium flowing in the second cooling medium pipe 46 via the second bypass pipe 66.

  The fuel cell system 2 includes a gas-liquid separator 68 that separates hydrogen contained in the waste hydrogen discharged from the hydrogen discharge manifold 22b of the fuel cell stack 1 and reaction product water. The water separated by the gas-liquid separator 68 is discharged out of the system through the exhaust / drain valve. On the other hand, the hydrogen separated by the gas-liquid separator 68 is sent to the hydrogen supply pipe 12 through the exhaust / drain valve 64 in order to reuse the hydrogen that is still in a high concentration.

The outer surface of the gas-liquid separator 68 is made of a plate-like member, and includes a relatively narrow inlet opening 72 and a circular opening 74 connected to the inlet opening 72 and extended from the inlet opening 72. The part 70 is fixed or integrally formed. The first bypass pipe 62 is supported by the clamp unit 70 by being fitted into the circular opening 74 via the inlet opening 72. Thereby, it can prevent that the 1st bypass piping 62 vibrates by the pulsation of the cooling medium which flows through the inside. Incidentally, the clamp unit 70 may be fixed to other vehicle components in the gas-liquid separator 68 except.

  Since the first bypass pipe 62 is often a relatively hard rubber hose, the hose is difficult to deform when pushed into the clamp portion 70, and the hose outer surface may be damaged. Further, since the vibration of the gas-liquid separator 68 propagates to the clamp part 70, the edge part of the circular opening 74 of the clamp part 70 and the outer peripheral surface of the first bypass pipe 62 are rubbed by the vibration, and also the hose outer surface May be damaged.

  Therefore, as shown in FIGS. 6 and 7, a cylindrical elastic member 76 made of, for example, sponge rubber or the like is provided on the outer peripheral portion of the first bypass pipe 62 corresponding to the position where the clamp portion 70 is fitted. The outer periphery of the member 76 is covered with a friction resistant member 78. The friction-resistant member 78 is formed of a net protector or a flex guard formed by knitting chemical fibers such as nylon, and has excellent friction resistance.

  By covering and protecting the first bypass pipe 62 with the elastic member 76 and the friction-resistant member 78 as described above, when the first bypass pipe 62 is pushed into the clamp part 70, the elastic member 76 passes through the inlet opening 72. By being crushed and deformed, the fitting into the circular opening 74 in the clamp part 70 is facilitated, and the first bypass pipe is rubbed by the friction-resistant member 78 due to rubbing with the inlet opening 72 during clamp insertion and vibration of the clamp part 70. It is possible to prevent the outer peripheral portion of 62 from being damaged.

  In the above-described embodiment, the example in which the fluid supply and discharge are performed from the same side end in the cell stacking direction has been described. However, the fuel cell stack pipe according to the present invention performs the fluid supply and discharge in the cell stacking. It is also applicable to fuel cell stacks of the type that are performed at different ends in the direction.

It is a top view of a fuel cell stack which shows supply and discharge of fluid roughly. It is a side view of fluid supply piping. It is a fragmentary sectional view near branch piping of fluid supply piping. It is a partial expanded sectional view which shows the modification of the division location of the 1st piping of FIG. It is a partial side view of a fuel cell system. It is a side view of the 1st bypass piping. It is the BB sectional drawing of FIG. 6 which shows the cross section of the elastic member which covers and protects 1st bypass piping, and a friction-resistant member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Fuel cell stack, 2 Fuel cell system, 10 Air supply piping, 12 Hydrogen supply piping, 14 Cooling medium supply piping, 16 1st stack, 18 2nd stack, 20 Fuel cell, 22a Hydrogen supply manifold, 22b Hydrogen discharge manifold 24a Air supply manifold, 24b Air discharge manifold, 26a Refrigerant supply manifold, 26b Refrigerant discharge manifold, 28a, 28b Current collecting plate, 30a, 30b Insulating plate, 32a, 32b End plate, 40 Main piping, 42 Branch pipe, 43a, 43b Branch branch, 43c Inner surface, 44 1st piping, 44a, 44b Piping end at the cutting location of the 1st piping, 46 2nd piping, 48 Mounting hole, 50 Flange, 52 Support member, 54 Cutting location, 56 Rubber hose, 58 Hose clamp, 62 1 bypass pipe, 64 water discharge valve, 66 second bypass piping, 68 gas-liquid separator, 70 clamp portion 72 inlet opening 74 circular openings, 76 elastic member, 78 rub member. L1, L2 Channel length, L3 distance.

Claims (3)

To each stack of the fuel cell stack comprising a plurality of first stacked body each constructed by sandwiching a laminated stack of fuel cells in the clamping member and the second stack side by side, the same side of the cell lamination direction A pipe for supplying a fluid that is a gas or a liquid from an end, the main pipe, a first pipe branched from the main pipe via a branch portion, and connected to the fluid supply port of the first laminate; A second pipe connected to the fluid supply port of the two-layered body, the first pipe has a flow path length shorter than that of the second pipe, and causes a pressure loss with respect to the fluid flowing inside the first pipe. There is a pressure loss part ,
The first pipe includes a part to be cut, and the part to be cut is connected via a cylindrical member made of a material having a rigidity lower than that of the pipe material, and the pressure loss portion is a pipe end facing the part to be cut. The portion is constituted by a throttle part having a smaller cross-sectional area than the other part of the first pipe, or by a convex part protruding radially inward from the inner peripheral surface of the cylindrical member at the dividing location. pipe for a fuel cell stack, characterized in Rukoto consists of narrowed portion of reduced cross-sectional area than other portions of the first pipe. The fuel cell stack pipe according to claim 1,
A fluid supplied to the second laminate by the second pipe is a cooling medium, a first bypass pipe which branches from the second pipe and divides the cooling medium and flows to the exhaust drain valve, and the exhaust drain valve And a second bypass pipe for joining the cooling medium discharged from the second pipe to the second pipe. The fuel cell stack pipe according to claim 2 ,
The first bypass pipe is fitted and supported by a clamp portion fixed to a gas-liquid separator that separates reaction product water from waste fuel gas discharged from the fuel cell stack. Piping for stack.

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