KR20130033823A - Fuel cell stack having improved the performance and structural stability - Google Patents

Abstract

PURPOSE: A fuel cell stack is provided to improve output performance by increasing cell distribution of a stack to improve output performance and to obtain structural stability. CONSTITUTION: A fuel cell stack comprises a cell module(10) consisting of multiple cells; end plates(14,15) arranged in both sides of the cell module; and an insert structure(30) which penetrates through the manifold flow channel(13) of the cell module and is fixed to the end plate. The insert structure consists of a plurality of flow guide(31) each of which penetrates the manifold flow channel of the cell module in a laminated direction; and a base member(34) coupled to one end of each flow guide. The flow guide has a guide flow channel for the flow fluid.

Description

Fuel cell stack having improved the performance and structural stability

The present invention relates to a fuel cell stack with improved output performance and structural stability, and more particularly, to improve cell distribution of fluid supplied in a stack and to reduce flow resistance, thereby improving output performance and structural stability through mechanical restraint. It relates to a fuel cell stack that can secure.

A fuel cell system mounted on a vehicle includes a fuel cell stack that generates electric energy largely, a fuel supply device for supplying fuel (hydrogen) to the fuel cell stack, and a supply of oxygen in the air, an oxidant required for an electrochemical reaction, to the fuel cell stack. It consists of an air supply system and a cooling system that removes the heat of reaction from the fuel cell stack to the outside of the system and controls the operating temperature of the fuel cell stack.

In such a fuel cell system, electricity is generated by an electrochemical reaction by hydrogen, which is a fuel, and oxygen in air, and heat and water are discharged as reaction byproducts.

Polymer Electrolyte Membrane Fuel Cell (PEMFC), which is currently being studied as the most important power source for driving a vehicle, is an electrochemical reaction on both sides of the membrane centered on an electrolyte membrane through which hydrogen ions move. Membrane Electrode Assembly (MEA) to which the catalytic electrode layer is attached, Gas Diffusion Layer (GDL), which reacts to evenly distribute the reactants, and transfer the generated electrical energy, reactants and cooling water Gasket and fastening mechanism for maintaining the airtightness and proper clamping pressure of the, and a separator to electrically connect the cells, and to move the reactor bodies and cooling water.

In the fuel cell, hydrogen as the fuel and oxygen (air) as the oxidant are respectively supplied to the anode and the cathode of the membrane electrode assembly through the flow path of the separator, and the hydrogen is the anode ('fuel electrode' or 'oxidation'). Oxygen (air) is supplied to the cathode ('air electrode' or 'oxygen electrode', also known as 'reduction electrode').

A fuel cell having such a configuration sequentially stacks unit cells (refer to reference numeral 2 of FIG. 2) composed of a membrane electrode assembly, a gas diffusion layer, and a separator plate to form a stack module, and further includes a pillar along the cell stacking direction. A manifold (see FIG. 2) forming a flow path having a column shape is formed long in the stacking direction of the stack while being integrally formed on the separator.

Fluids such as hydrogen, air, and coolant in the stack move through the flow path of the manifold, and are supplied from the first cell close to the stack inlet to the last cell far from the stack inlet. (See FIG. 1).

On the other hand, the fuel cell stack mounted on a vehicle satisfies the requirement by stacking hundreds of unit cells as a high output is required, and in the assembly of the fuel cell stack, the components of the unit cell constituting the stack ( The surface pressure acting between the membrane electrode assembly, the gas diffusion layer, and the separator plate has a great influence on the stack output.

Existing fuel cell stacks are assembled by arranging end plates 3 on both sides of the stacked cell modules 1 before and after as shown in FIG. 1 and compressing them with a press device. It is fastened and assembled to fix the front and rear end plates 3 using the band 4.

However, the fuel cell stack has a problem in that fluids such as hydrogen, oxygen (air), cooling water, etc. are not supplied in the same amount to each cell because they are introduced and supplied along the stacking direction of the cells at the side of the stack, which is a combination of multiple cells. .

In particular, referring to FIG. 3, a cell far from the stack inlet may have a shortage of supply fuel supplied through a flow path than a reference flow rate, thereby causing problems related to performance and durability of the fuel cell.

In order to prevent the shortage of the fuel supply of the existing stack, the excess fuel is supplied, but this also causes a problem that the vehicle fuel economy is deteriorated.

In addition, the conventional fuel cell stack has a problem in that structural stability is deteriorated when the gasket or the gas diffusion layer is deteriorated and elasticity is reduced by applying a structure for compressing and supporting end plates on both sides of the stack with a fastening band.

In addition, the conventional fuel cell stack has a problem that it is difficult to discharge the fuel distribution due to the unevenness of the separator plate when condensate is generated inside, and also the end due to the lack of space to install the fastening band near the manifold by design Plate bending occurs and this causes a problem of inferior surface pressure distribution and sealing property in the stack.

The present invention has been invented to solve the above problems, to improve the cell distribution of the stack to improve the output performance and to provide a fuel cell stack that can ensure structural stability through mechanical restraint / fixation There is this.

In order to achieve the above object, the present invention provides a cell module comprising a plurality of stacked cells; End plates disposed on both front and rear sides of the cell module; It provides a fuel cell stack with improved output performance and structural stability, characterized in that it comprises a; insert structure fixed to the end plate of the front and rear both sides through the manifold flow path of the cell module.

The insert structure includes a plurality of flow guides each passing through the manifold flow path of the cell module in the stacking direction of the cell and a base member having one end of each flow guide integrally formed, and the flow guide flows into the manifold. It is characterized in that it is formed to have a guide flow path for the flow of the fluid.

Preferably, the insert structure has one end portion of the flow guide inserted into the through hole of the front end plate, and one end portion inserted into the through hole and a pressure elastic member for pushing and fixing one end portion inserted into the through hole in the cell stacking direction. It is characterized in that the fixed assembly by the fixing means for fixing by pushing in a direction perpendicular to the stacking direction.

In addition, the insert structure is characterized in that the base member is locked in the rear end plate is fixed as the flow guide passes through the rear end plate.

Also preferably, the fixing means is a fixing ball that is placed in the position fixing hole of the flow guide through the front end plate, a spring member for pushing the fixing ball in a direction perpendicular to the cell stacking direction, and the front end It is characterized by consisting of a bolt member which is assembled to the plate to exert the elastic restoring force by compressing the spring member.

In addition, the pressing elastic member is inserted into the through hole of the front end plate, characterized in that the high elastic spring member is sandwiched between the flow guide and the front end cover.

In addition, the flow guide is characterized in that it has a tapered guide surface that can be directed to the cell module side by redirecting the flow of fluid introduced in the stacking direction of the cell.

In addition, the flow guide has a plurality of position fixing holes in a row in the cell stacking direction on the outer wall surface, the ball for fixing the fixing means is seated in any one of the position fixing holes formed in a row according to the compression degree of the cell module. It is characterized by.

In addition, the insert structure is characterized in that the surface is coated with a hydrophobic fluorine resin for electrical insulation and rapid discharge of condensate.

The fuel cell stack according to the present invention can obtain the following effects.

1. Since a plurality of cells are inserted into the flow guide of the insert structure to be laminated and assembled, it is composed of a mechanically constrained structure to ensure structural stability, and also easy to assemble, thereby reducing stack production time.

In addition, the fastening structure can be deleted by the existing fastening structure, it is possible to improve the surface pressure imbalance according to the position of the fastening band.

2. The tapered cross-section application of the flow guide controls the pressure and flow of fluids such as hydrogen, air, and coolant to improve cell distribution of the fluid in the stack and reduce the flow resistance to improve output performance.

3. In the conventional stack, condensate accumulates therebetween due to the unevenness of the separator, and flows into the flow path in the cell, thereby preventing the diffusion of the gas. You can prevent slumping.

4. As stack assembly is possible at the end manifold of the end plate, bending of the end plate can be prevented, thereby ensuring uniform surface pressure distribution and sealing property.

1 is a view showing a conventional fuel cell stack
2 is a diagram illustrating a stack structure of conventional fuel cell unit cells.
3 is a diagram illustrating a cell distribution analysis result of a fluid in a conventional fuel cell stack.
4 is an exploded perspective view illustrating a fuel cell stack according to an embodiment of the present invention.
5 is a perspective view illustrating a fuel cell stack of FIG. 4.
6 is a cross-sectional view taken from AA of FIG. 5.
FIG. 7 is an enlarged view of “B” of FIG. 6.
8 is a perspective view showing the insert structure of the present invention;
9 is a view showing the results of fluid flow analysis according to the flow cross-sectional area and shape change of the flow guide of the present invention

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a fuel cell stack with improved output performance and structural stability. The present invention relates to a fuel cell stack that eliminates an existing fastening band and instead forms an insert structure inserted into the stack to secure structural stability of the stack and to improve surface pressure imbalance in the stack. To help.

In addition, by applying a shape to improve the cell distribution of the fluid in the stack to the insert structure it is possible to increase the performance of the fuel cell.

Accordingly, the fuel cell stack according to the present invention includes an insert structure 30 installed in a form inserted into the cell module 10, as shown in FIGS.

Specifically, in the present invention, the fuel cell stack includes a cell module 10 composed of multiple cells 11 stacked, end plates 14 and 15 disposed on both front and rear sides of the cell module 10, and the cells. Comprising an insert structure 30 is fixed to the end plate (14, 15) of the front and rear both sides through the manifold flow path 13 of the module 10 in the stacking direction of the cell (11).

As shown in FIG. 4, the cell module 10 has a manifold 12 that forms a flow path 13 for inflow and outflow of fluid on both left and right sides thereof, and is formed to be long in the stacking direction of the cell. The insert structure 30 penetrates the flow passage 13 of the manifold 12.

Here, the fluid is one or more of hydrogen used as fuel in a fuel cell, air used as an oxidant, and cooling water used to control the operating temperature of the stack.

The insert structure 30 includes six flow guides 31 which respectively penetrate the manifold flow path 13 of the cell module 10 in the cell stacking direction and a base having one end of each flow guide 31 integrally formed therein. Member 34.

As shown in FIG. 6, the flow guide 31 is inserted and mounted in close contact with the manifold flow path 13 of the cell module 10, and the guide flow path (for the flow of fluid introduced into the manifold 12) is provided. It is formed to have S).

In this embodiment, the flow guide 31 is formed in a shape having a c-shaped cross section long in the cell stacking direction. Referring to FIGS. 6 and 8, the flow guide 31 has a guide flow path S tapered from the front to the rear of the stack. Is formed.

Specifically, the flow guide 31 is formed of a pair of parallel side members forming the outer wall of the guide flow path (S) and a guide surface 33 for integrally connecting the pair of side members along the cell stacking direction. The guide surface 33 may be formed to have a gradually thicker thickness in the cell stacking direction.

Accordingly, the cross section of the guide flow path S gradually decreases as the flow guide 31 moves forward from the rear of the stack, and as shown in FIG. 6, the guide flow path S narrows from the front of the stack toward the rear, resulting in cell stacking. By redirecting the flow of fluid introduced in the direction it can be directed to the cell module 10 side.

In other words, the flow guide 31 receives the flow of fluid introduced in the cell stacking direction along the flow path 13 of the manifold 12 through the stack inlet 25 by the tapered guide surface 33. It is formed to be able to redirect to (10).

Such a flow guide 31 guides the flow of fluid toward the cell module 10 while the guide flow path S gradually narrows from the front of the stack to the rear of the stack inlet from the cell close to the stack inlet 25. This allows a relatively uniform flow rate of fluid to be supplied to distant cells.

In addition, since the flow guide 31 is integrally formed with the base member 34, the flow guide 31 is appropriately disposed on the base member 34 according to the position of the flow path 13 of the manifold 12.

The insert structure 30 formed as described above has both ends of the flow guide 31 penetrating the flow passage 13 of the manifold 12 on the end plates 14 and 15 disposed on both front and rear sides of the cell module 10. It is assembled to be fixed.

4 and 6, the insert structure 30 is secured to the endplates 14, 15 such that the flow guide 31 passes through the endplate 14 behind the stack and then the plurality of cells ( 11 are inserted into the flow guide 31 to be laminated and assembled, and the flow guide 31 is mounted in a structure that penetrates the manifold flow path 13 of the cell module 10, wherein the base member 34 is The rear end plate 14 (or the rear end plate 14) is fixed to the rear end plate 14 so that one end of the flow guide 31 is fixed to the rear end plate 14.

And, in order to prevent the rear detachment of the base member 34 inserted into the rear end plate 14, the rear end cover 36 is integrally mounted to the rear end plate 14 at the rear end of the base member. .

In the insert structure 30 in which one end of the flow guide 31 is fixed to the rear end plate 14 as described above, the other end of the flow guide 31 has an end plate in front of the stack as shown in FIGS. 6 and 7. 15, or front endplate).

Accordingly, the other end of the flow guide 31 is inserted into the through hole 16 of the front end plate 15 to be tightly fixed. For this purpose, the fixing means 20 and the pressure elastic member 18 are mounted.

The fixing means 20 serves to fix and support the other end of the flow guide 31 inserted into the through hole 16 of the front end plate 15 in a direction perpendicular to the cell stacking direction. The elastic member 18 serves to fix and support the other end of the flow guide 31 inserted into the through hole 16 in the cell stacking direction.

6 and 7, the fixing means 20 is mounted through the front end plate 15 on both sides of the front end plate 15, respectively, and the end of the flow guide 31 is placed in the cell stacking direction. A fixing ball 21 which is pushed in a direction perpendicular to the through hole 16 and fixed to the through hole 16, a spring member 22 which can apply a pushing force to the fixing ball 21, and the spring Compression member 22 may be composed of a bolt member 23 that can exert an elastic restoring force.

The fixing ball 21 penetrates one side of the front end plate 15 and receives a force from the spring member 22 in a state where it is placed in the position fixing hole 32 of the flow guide 31. The end of the) is pushed and fixed in close contact with the through hole 16, the spring member 22 penetrates through the front end plate 15 and is positioned on the fixing ball 21 in the bolt member 23 Is assembled to one side of the front end plate 15 is compressed and exerts an elastic restoring force, the spring member 22 is to push the fixing ball 21 in a direction perpendicular to the cell stacking direction.

The pressurized elastic member 18 is inserted into the through hole 16 of the front end plate 15 and is positioned at the end of the flow guide 31. In this state, the front end cover 15 is inserted into the front end plate 15. 19 is fitted to the front end plate 15 to be compressed between the other end of the flow guide 31 and the front end cover 19, thereby compressing and supporting the flow guide 31 by pushing in the cell stacking direction. .

The pressure elastic member 18 may be composed of a high elastic spring member having a high elastic force, and absorbs the impact applied to the insert structure 30 and serves to adjust the distance between the front and rear end plates (14, 15). have.

In addition, as shown in FIGS. 5 to 7, the front end cover 19 has a hole formed at a position corresponding to the through hole 16, which is the through hole 16 of the front end plate 15. And stack inlet 25 and stack outlet 26, respectively.

In addition, the flow guide 31 is formed in the stacking direction of the cell on the outer wall surface (or outer surface of the fixing ball) of the fixing means 20, specifically, the guide surface 33 facing both sides of the stack. Position fixing holes 32 are formed in a line, the fixing ball 21 of the fixing means 20 is seated in the position fixing holes 32 to guide the flow guide 31 of the front end plate 15 It comes in close contact with the through hole 16.

Accordingly, when the surface pressure of the stack is reduced, the cell module 10 is compressed by using a press device, and the position fixing hole 32 of the flow guide 31 on which the fixing ball 21 is seated is appropriately changed to stack the stack. Can improve the surface pressure.

That is, the flow guide 31 is fixed to the ball 21 for fixing the fixing means 20 of any one of the position fixing holes 32 formed in a row in accordance with the degree of compression of the cell module 10 When the predetermined surface pressure drops, the fixing ball 21 is fixed to the appropriate position fixing hole 32 so that the cell module 10 can be fixed in a constant compressed state, thereby making the surface pressure adjustable.

In addition, the insert structure 30 is preferably surface-coated with a hydrophobic fluorine resin (for example, Teflon) in order to quickly discharge and remove condensate as well as electrical insulation.

On the other hand, Figure 9 is a view showing the results of the fluid flow analysis according to the flow cross-sectional area and the shape change of the flow guide of the present invention, depending on the degree of inclination of the tapered guide surface of the flow guide far away from the cell and the stack inlet near the stack inlet It can be seen that the flow rate difference of the cell is different, and accordingly, the cell distribution can be improved according to the inclination of the guide surface.

10: cell module
11: cell
12: manifold
13: (manifold) euro
14: rear end plate
15: front end plate
16: through hole
18: pressure elastic member
19: front end cover
20: Fixing means
21: fixing ball
22: spring member
23: bolt member
25: stack entrance
26: stack exit
30: insert structure
31: Flow guide
32: position fixing hole
33: guide surface
34: base member
36: rear end cover
S: guide euro

Claims (9)

A cell module consisting of stacked multiple cells;
End plates disposed on both front and rear sides of the cell module;
An insert structure that is assembled to and fixed to the end plates at both front and rear sides of the cell module through the manifold flow path;
Fuel cell stack with improved output performance and structural stability, characterized in that configured to include.
The method according to claim 1,
The insert structure includes a plurality of flow guides each passing through the manifold flow path of the cell module in the stacking direction of the cell and a base member having one end of each flow guide integrally formed, and the flow guide flows into the manifold. A fuel cell stack with improved output performance and structural stability, characterized in that it is formed to have a guide flow path for the flow of the fluid.
The method according to claim 1,
The insert structure has one end portion of the flow guide inserted into the through hole of the front end plate, and one end portion inserted into the through hole and one end portion inserted into the through hole in the cell stacking direction. The fuel cell stack with improved output performance and structural stability, characterized in that the assembly is fixed by the fixing means for pushing in a direction perpendicular to the fixed.
The method according to claim 1,
The insert structure is a fuel cell stack with improved output performance and structural stability, characterized in that the base member is fixed in the rear end plate is fixed as the flow guide penetrates the rear end plate.
The method according to claim 3,
The fixing means is assembled to the fixing ball that is placed in the position fixing hole of the flow guide through the front end plate, a spring member for pushing the fixing ball in a direction perpendicular to the cell stacking direction, and the front end plate The fuel cell stack with improved output performance and structural stability, characterized in that consisting of a bolt member that can exert the elastic restoring force by compressing the spring member.
The method according to claim 3,
The pressurized elastic member is inserted into the through hole of the front end plate, the fuel cell stack with improved output performance and structural stability, characterized in that the high elastic spring member sandwiched between the flow guide and the front end cover.
The method according to claim 2,
The flow guide is a fuel cell stack with improved output performance and structural stability, characterized in that having a tapered guide surface which can be directed to the cell module side by redirecting the flow of fluid introduced in the stacking direction of the cell.
The method according to claim 2,
The flow guide has a plurality of position fixing holes formed in a row in the cell stacking direction on the outer wall surface, the ball for fixing the fixing means is seated in any one of the position fixing holes formed in a line according to the compression degree of the cell module A fuel cell stack with improved output performance and structural stability.
The method according to claim 1,
The insert structure is a fuel cell stack with improved output performance and structural stability, characterized in that the surface is coated with a hydrophobic fluorine resin for electrical insulation and rapid discharge of condensate.

Images