KR100556814B1 - Stack of fuel cell - Google Patents

Abstract

The present invention relates to a stack of fuel cells, the present invention comprising: an electrolyte membrane; A fuel electrode and an air electrode stacked on both sides of the electrolyte membrane; A fuel flow path through which the fuel circulates and an air flow path through which the air circulates are formed, and a fuel side manifold communicating with the fuel flow path and an air side manifold communicating with the air flow path are formed, and an insulating layer is formed between both manifolds and the flow path. A bipolar plate disposed to be in contact with each of the fuel electrodes and the air electrodes; A current collector plate disposed on an outer surface of both outermost bipolar plates to collect electricity; A fuel port communicating with the fuel side manifold of the bipolar plate and an air passage communicating with the air side manifold to support the bipolar plate with the current collector plate therebetween; The battery can be further miniaturized. In addition, by forming the end plate of a plastic material, but by forming a reinforcement portion with a rib, it is possible to increase the reliability of the fuel cell by stably supporting the stack while reducing the weight of the stack. In addition, the sealing between the manifold and the flow path of the bipolar plate is interlocked with a ring sealing member to prevent leakage of fuel and air, thereby increasing the efficiency of the stack, and fixing the electrolyte membrane between the two ring sealing members to increase stack reliability and efficiency. It can increase.

Description

Stack of Fuel Cells {STACK OF FUEL CELL}

1 is a schematic diagram showing a conventional fuel cell;

2 is a perspective view showing a stack of a conventional fuel cell;

3 is a cross-sectional view showing a stack of a conventional fuel cell,

4 is an exploded perspective view showing a stack of the fuel cell of the present invention;

Figure 5 is a plan view shown to explain a processing method of the communication hole connecting the manifold and the flow path in the bipolar plate of the present invention stack,

6 and 7 are a plan view showing a ring-shaped sealing member for sealing the manifold and the flow path in the bipolar plate of the present invention stack,

8 is a cross-sectional view showing a state of supporting the electrolyte membrane using a ring-shaped sealing member in the bipolar plate of the present invention stack,

9 and 10 are an exploded perspective view of the end plate and the collector plate of the present invention stack,

11 is a cross-sectional view showing a coupling state of the end plate and the collector plate of the present invention stack;

Figure 12 is a perspective view of the stack shown to explain the fuel and air supply to the stack of the present invention.

** Description of symbols for the main parts of the drawing **

110: unit cell 111: electrolyte membrane

112: fuel electrode 113: air electrode

114: bipolar plate 114a: fuel flow path

114b: air passage 114c: fuel side manifold

114d: air side manifold 114e: communication hole

114f: Volumetric sealing member 114g: Ring type sealing member

115: collector plate 115a: collector

115b: fastening portion 115c: fastening hole

116: end plate 116a: frame portion

116b: reinforcement 116c: hollow

116d: reinforcement 116e: fuel port

116f: Air vent 116g: Current collector seating surface

116h: Bolt hole 116i: Tightening groove

117c: Tightening bolt 117b: Tightening nut

118: fuel supply pipe 119: air supply pipe

The present invention relates to a stack of fuel cells, and more particularly to a stack of fuel cells provided with a fuel side manifold and an air side manifold therein to simplify the structure.

Until now, most of the energy used by humans is derived from fossil fuels, but fossil fuels have serious adverse effects on the environment such as air pollution, acid rain, and global warming, and due to their low energy efficiency, interest in alternative or renewable energy is gradually increasing. It is rising.

The fuel cell is proposed as an alternative to such fossil fuels. Unlike conventional cells (secondary cells), the fuel cell is supplied with fuel (hydrogen gas or hydrocarbon) to the anode and oxygen to the cathode from the outside to electrolyze water. It is a battery system that generates electricity and heat by undergoing an electrochemical reaction in a reverse reaction.

If the fuel cell is classified according to the type of electrolyte, the phosphoric acid fuel cell operating at around 200 ° C, the alkaline electrolyte fuel cell operating at 60 to 110 ° C, the polymer electrolyte fuel cell operating at room temperature to 80 ° C, about 500 ~ Molten carbonate electrolyte fuel cells operating at a high temperature of 700 ℃, and solid oxide fuel cells operating at a high temperature of 1000 ℃ or more.

As shown in FIG. 1, a fuel cell typically includes a stack 10 including a fuel electrode and an air electrode to generate electrical energy by an electrochemical reaction between hydrogen and oxygen, and a fuel supplying fuel in an aqueous solution state including hydrogen to the fuel electrode. And a supply unit 20, an air supply unit 30 for supplying air containing oxygen to the cathode, and an electric energy output unit 40 for supplying electrical energy generated by the stack 10 to the load.

The stack 10 stacks a plurality of single cells 11 as shown in FIGS. 2 and 3, and fixes both upper and lower sides by external manifolds 12 and 13, respectively.

The unit cell 11 includes an electrolyte membrane 11a and a fuel electrode 11b and an air electrode 11c stacked on both sides with the electrolyte membrane 11a interposed therebetween, and the outside of the fuel electrode 11b and the air electrode 11c. It is composed of a plurality of bipolar plates (separator or bipolar plate) (11d) (11e) to be laminated to the fuel and air to circulate while contacting the anode (11b) and the cathode (11c), respectively.

The electrolyte membrane 11a uses a polymer membrane that transfers H ⁺ , such as a polymer ion exchange membrane that exhibits electrical conductivity in a wet state.

The anode 11b and the cathode 11c are composed of a support (not shown) and a catalyst layer (not shown) stacked on both sides of the support, wherein the support is formed of metallic nickel foam, and the catalyst layer is hydrogenated and reduced oxygen. It is formed of a hydrogen storage alloy suitable for the reaction.

The bipolar plates 11d and 11e use a metal material such as graphite having good electrical conductivity and high corrosion resistance, and fuel passes through each inner surface of the bipolar plates 11b and the air electrode 11c. A fuel channel Cf and an air channel Co through which air passes are formed.

In addition, the bipolar plates 11d and 11e provided between the unit cells 11 form a fuel flow path Cf on one side and an air flow path Co on the other side, and are installed at both ends of the stack 10. The bipolar plates 11d and 11e which form the fuel flow path Cf or the air flow path Co only on the inner side surface.

The manifolds 12 and 13 communicate with the fuel supply pipe 22 of the fuel supply unit 20 on the inner side of the unit cell 11 in contact with each other, and collectively with the fuel flow path Cf of each unit cell 11. Air passages 12b and 13b which communicate with the air passages Co of the unit cells 11 in communication with the fuel passages 12a and 13a communicating with the air supply pipe 31 of the air supply unit 30. ).

In addition, an insulating plate 14 and 15 is interposed between the manifolds 12 and 13 and the unit cell 11 for insulation between the unit cells 11 and the manifolds 12 and 13. Doing. The insulating plates 14 and 15 include the fuel passages 12a and 13a and the air passages 12b and 13b of the manifolds 12 and 13 described above with the fuel passage Cf of the unit cell 11. Fuel through holes 14a and 15a and air through holes 14b and 15b communicating with the air passage Co are formed.

In the figure, 21 is a fuel tank, 23 is a fuel pump, 32 is an air pump.

The conventional fuel cell as described above operates as follows.

That is, the fuel and air supplied to the fuel flow path Cf and the air flow path Co of the bipolar plates 15 and 16 are in contact with the fuel electrode 13 and the air electrode 14, respectively. Generates energy and heat energy.

Accordingly, electromotive force is generated between the fuel electrode 13 and the air electrode 14, and the electromotive force is collected through current collector plates 17 and 18 provided at both ends of the stack 10 in which the plurality of unit cells 11 are stacked. The current output from the current collector plates 17 and 18 was supplied to the load.

However, in the stack of the conventional fuel cell as described above, as described above, the upper and lower sides of the unit cell 11 are coupled to the external manifolds 12 and 13 to supply fuel and air. As the volume of 10) increased, it was inconvenient to store or transport, especially in the case of small-capacity portable.

In view of this, in the case of the internal manifold including the fuel passages 12a and 13a and the air passages 13a and 13b inside the bipolar plates 11d and 11e, the bipolar plates 11d and 11e described above. Since it is to be closely in contact with the insulating plates 14, 15 therebetween, there is a problem that the assembly property is lowered.

The present invention has been made in view of the problems of the conventional fuel cell stack as described above, and it is an object of the present invention to provide a stack of fuel cells that can increase the assemblability while reducing the volume of the stack.

In order to achieve the object of the present invention, the electrolyte membrane; A fuel electrode and an air electrode stacked on both sides of the electrolyte membrane; A fuel flow path through which the fuel circulates and an air flow path through which the air circulates are formed, and a fuel side manifold communicating with the fuel flow path and an air side manifold communicating with the air flow path are formed, and an insulating layer is formed between both manifolds and the flow path. A bipolar plate disposed to be in contact with each of the fuel electrodes and the air electrodes; A current collector plate disposed on an outer surface of both outermost bipolar plates to collect electricity generated when ions move between both electrodes; It provides a stack of fuel cells including a fuel port communicating with the fuel side manifold of the bipolar plate and an air port communicating with the air side manifold to support the bipolar plate with the current collector plate therebetween.

Hereinafter, a stack heat dissipation device of a fuel cell according to the present invention will be described in detail with reference to an embodiment shown in the accompanying drawings.

4 is a perspective view illustrating an exploded view of the stack of the fuel cell of the present invention, FIG. 5 is a plan view illustrating a processing method of a communication hole connecting a manifold and a flow path in a bipolar plate, and FIGS. 6 and 7 are bipolar plates. Figure 8 is a plan view showing a ring-shaped sealing member for sealing the manifold and the flow path, Figure 8 is a cross-sectional view showing a state supporting the electrolyte membrane using a ring-shaped sealing member in the bipolar plate, Figures 9 and 10 are end plates and collector plates 11 is a disassembled perspective view, and FIG. 11 is a cross-sectional view illustrating a coupling state of an end plate and a current collector plate, and FIG. 12 is a perspective view of a stack shown to explain a fuel and air supply method.

As shown in the drawing, a stack of a fuel cell according to the present invention is formed by stacking a plurality of unit cells 110, and each unit cell 110 is an electrolyte membrane made of a polymer ion exchange membrane so as to have electrical conductivity in a wet state. 111, an anode 112 and an anode 113 stacked on both sides with the electrolyte membrane 111 interposed therebetween, and a fuel passage 114a and an air passage 114b formed therebetween, and the fuel passage 114a and air. A fuel side manifold 114c and an air side manifold 114d are provided to communicate with the flow path 114b, and an insulating layer (not shown) is formed between the two flow paths 114a and 114b and the manifolds 114c and 114d. A bipolar plate 114 and 114 stacked on the outer side of the fuel electrode 112 and the air electrode 113 and both bipolar plates 114 and 114 to form a current collecting electrode. On the fuel side manifolds 114c of the current collector plates 115 and 115 made of copper plates and the bipolar plates 114 and 114. The air passages 116f and 116f communicating with the fuel passages 116e and 116e communicating with each other and the air side manifold 114d are formed so that the current collector plates 115 and 115 are interposed therebetween. End plates 116 and 116 for supporting 114.

As described above, the fuel electrode 13 and the air electrode 14 are composed of a support layer and a catalyst layer laminated on both sides of the support, and the support layer is formed of porous carbon paper or carbon cross, and the catalyst layer is used for oxidation of hydrogen and reduction of oxygen. Preference is given to using suitable platinum. The catalyst layer is formed in the form of coating fine platinum particles on the surface of the fine carbon particles in order to increase the effective surface area of the catalyst.

The bipolar plates 114 and 114 use a metal material such as graphite having good electrical conductivity and strong corrosion resistance, and fuel passages 114a through which fuel passes through the inner surfaces of the anode 112 and the cathode 113. And an air passage 114b through which air passes. Here, the bipolar plates 114 and 114 installed between the unit cells 110 form a fuel passage 114a on one side and an air passage 114b on the other side, while bipolar plates are installed on both ends of the stack 10. The plates 114 and 114 form the fuel flow passage 114a or the air flow passage 114b only on the inner side surface.

In addition, on both the upper and lower sides of the bipolar plate 114, fuel side manifolds 114c and air side manifolds 114d respectively communicating with the fuel passage 114a and the air passage 114b are formed on both the left and right sides, respectively. .

The insulating layer made of Teflon is formed between the fuel side manifold 114c and the fuel passage 114a or the air side manifold 114c and the air passage 114b.

In addition, the bipolar plate 114 passes through the fuel side manifold 114c and the air side manifold 114d at its outer side as shown in FIG. 5 so as to communicate with the fuel passage 114a and the air passage 114b, respectively. Communication holes 114e and 114e are formed, but the volume sealing members 114f and 114f extend from the rim surface to the main surface of each manifold 114c and 114d so as to prevent fuel and air from leaking out of the stack. It is preferable to seal by pinching.

In addition, on both sides of the bipolar plate 114, as shown in Figs. 6 and 7, ring-shaped sealing members formed individually or integrally around the manifolds 114c and 114d and around the respective passages 114a and 114b. It is preferable to seal each manifold 114c (114d) and each flow path 114a (114b) of the adjacent bipolar plate 114 by fitting 114g.

Here, it is preferable that the ring-shaped sealing member 114g is engaged with the ring-shaped sealing member 114g of the neighboring bipolar plate 114 as shown in FIG. It is preferable to sandwich the electrolyte membrane 111 so that the electrolyte membrane 111 can be firmly fixed.

9 and 10, the current collector plate 115 extends and bends one side of the current collector 115a to be inserted into and fixed to the edge-side current collector plate seating surface 116g of the end plate 116 to be described later. 115b is formed, and a fastening hole 115c is formed in the fastening portion 115a to bolt the fastening groove 116i provided on the side surface of the edge of the end plate 116 to be described later.

End plate 116 is formed of a light plastic material, but as shown in Figure 9 to form a frame portion 116a in the shape of a band and the inner circumferential surface of the frame portion 116a to form a reinforcement portion 116b with ribs that cross each other, As shown in 10, the inside of the hollow plate may be formed, but the hollow portion 116c may include a plurality of rib reinforcement portions 116d.

In addition, a plurality of fuel passages 116e are formed in the lower half of the end plate 116 in the transverse direction, whereas a plurality of air passages 116f are formed in the transverse direction in the upper half, and each fuel passage 116e and the air passages ( 116f) is preferably made available for use by the outer bipolar plate 114, depending on the type of installation of the system.

In addition, as shown in Figure 11 to form a current collector plate seating surface (116g) for mounting the current collector plate 115 from the inner side surface of the end plate 116 to the edge side, the current collector seating surface (116g) It is preferable to form the step to be shallower or equal to the thickness of the front plate 115 to increase the current collecting efficiency.

In addition, both end plates 116 are fastened by tightening the fastening bolts 117a and the fastening nuts 117b in a state in which the plurality of unit cells 111 are stacked therebetween. A plurality of bolt holes 116h are formed between the upper and lower edges of the upper and lower edges thereof.

On the other hand, as shown in FIG. 12, the fuel supply pipe 118 communicating with the fuel side manifold 114c of the bipolar plate 114 has the above-described end such that fuel is supplied upward from the fuel passage 114a of the bipolar plate 114. The air supply pipe 118, which is connected to the fuel port 116e of the plate 116 and communicates with the air side manifold 114d, allows the air to be supplied downward from the air flow path 114b of the bipolar plate 114. Connecting to the air port 116f of the end plate 116 is preferable because fuel and air can be evenly distributed between each fuel flow path and air flow path.

In the drawings, the same reference numerals are given to the same parts as in the prior art.

In the figure, reference numeral 114h is a through hole.

The stack of the fuel cell of the present invention as described above has the following effects.

That is, fuel is supplied from the fuel tank (shown in FIG. 1) 21 to the fuel side manifold 114c of the stack 110 via the fuel supply pipe 118, and the fuel is supplied to the fuel side manifold 114c. Through the fuel-side communication hole 114e for each unit cell 110 communicated with each other, it is evenly distributed to the fuel passage 114a to perform an electrochemical oxidation reaction while passing through each fuel passage 114a.

On the other hand, air is supplied to the air side manifold 114d through the air supply pipe 119 in the atmosphere, and the air is provided in the air side communication hole for each unit cell 110 communicated with the air side manifold 114d. It is distributed to the air passage 114b through 114e) and performs an electrical reduction reaction while passing through each air passage 114b at a time.

In this process, electromotive force is generated between the anode 112 and the cathode 123, and the electromotive force is output through the current collector plate 115 provided at both ends of the stack in which the plurality of unit cells 110 are stacked. After supplying to the load.

Here, by forming the fuel side manifold 14c and the air side manifold 114d inside the bipolar plate 114, respectively, the overall structure of the stack can be simplified, thereby reducing the volume of the stack, particularly small or portable. In this case, it can be easily transported and stored.

In addition, the fuel side manifold 114c and the air side manifold 114d need to interpose a separate insulating plate by coating an insulating layer made of Teflon material between the fuel passage 114a and the air passage 114b, respectively. This makes the stack smaller.

Further, the fuel side manifold 114c and the fuel passage 114a or the air side manifold 114d and the air passage 114b are directly communicated with each other at the edge of the bipolar plate 114, and then each manifold 114c ( By sealing the outside of 114d with the volume sealing member 114f to seal the manifolds 114c and 114d described above, the respective manifolds 114c and 114d and the flow paths 114a and 114b are easily communicated. Can increase productivity.

In addition, the fuel flow path 114a is sealed by sealing the fuel flow passage 114a and the air flow passage 114b of the bipolar plate 114 with a ring-shaped sealing member 114g formed individually or integrally with the manifolds 114c and 114d. ) And the efficiency of the stack can be improved by effectively preventing the leakage of fuel or air circulating in the air passage 114b.

In addition, the sealing effect can be enhanced by disposing the ring-shaped sealing members 114g to be engaged with each other, and the electrolyte membrane is interposed between the two ring-shaped sealing members 114g and 114g facing each other. By allowing the 111 to be held by the ring-shaped sealing member 114g, the electrolyte membrane 114g can be more firmly fixed.

In addition, the end plates 116 and 116 supporting the left and right sides of the stack are formed of a light plastic material, and ribs are formed at the center thereof with ribs to reinforce the portions 116b and 116d, thereby greatly reducing the overall weight of the stack and providing rigidity. To increase the stability of the stack.

In addition, the volume of the stack can be further reduced by manufacturing the current collector plates 115 and 115 of the stack in a thin plate and fixing them to the end plates 116 and 116 described above.

The stack of the fuel cell according to the present invention is formed by forming an internal manifold on a bipolar plate, coating the inner manifold and each flow path with an insulating layer, and fabricating a current collector plate in a thin plate and fixing it to an end plate. The volume can be greatly reduced, making the fuel cell even smaller.

In addition, by forming an end plate for supporting the left and right sides of the stack with a plastic material but forming a reinforcement part with ribs, the stack can be more stably supported to increase the reliability of the fuel cell.

In addition, the sealing between the manifold and the flow path of the bipolar plate is interlocked with a ring sealing member to prevent leakage of fuel and air, thereby increasing the efficiency of the stack. To increase the reliability and efficiency of the stack.

Claims (14)

An electrolyte membrane; A fuel electrode and an air electrode stacked on both sides of the electrolyte membrane; A fuel flow path through which the fuel circulates and an air flow path through which the air circulates are formed, and a fuel side manifold communicating with the fuel flow path and an air side manifold communicating with the air flow path are formed, and an insulating layer is formed between both manifolds and the flow path. A bipolar plate disposed to be in contact with each of the fuel electrodes and the air electrodes; A current collector plate disposed on an outer surface of both outermost bipolar plates to collect electricity generated when ions move between both electrodes;  And an end plate forming a fuel port communicating with the fuel side manifold of the bipolar plate and an air port communicating with the air side manifold to support the bipolar plate with the current collector plate therebetween. The method of claim 1, A stack of fuel cells, wherein the insulating layer of the bipolar plate is made of Teflon material. The method of claim 1, The current collector plate extends and bends one side thereof to form a fastening part, and the fastening part forms a fastening hole for fastening bolts on an edge side of the end plate. The method of claim 3, The end plate is a stack of fuel cells, characterized in that for forming the current collector plate seating surface for mounting the current collector plate from the inner side to the edge side so as to be less than or equal to the thickness of the current collector plate. The method according to claim 1 or 4, The end plate has a strip-shaped frame portion, and the inner circumferential surface of the frame portion is formed by forming a reinforcement portion with ribs intersecting with each other. The method according to claim 1 or 4, An end plate is a stack of fuel cells, characterized in that the inside is formed of a hollow hollow plate, the reinforcement portion of several ribs formed in the hollow. The method of claim 1, Both end plates have a plurality of unit cells therebetween and a plurality of bolt holes to form a plurality of bolt holes to fasten by tightening the edge and the edge between the edge of the stack of fuel cells. The method of claim 1, The bipolar plate has a stack of fuel cells in which a communication hole is formed so that the fuel side manifold and the air side manifold communicate with the fuel passage and the air passage, respectively. The method of claim 8, The communication hole is formed through the manifold through the manifold from the rim surface of the bipolar plate to penetrate each flow path, but the fuel cell stack, characterized in that the sealing sealing the volume type sealing member from the rim surface to the main surface of each manifold. The method of claim 1, A stack of fuel cells characterized by sealing each manifold and each flow path of a neighboring bipolar plate by inserting ring-shaped sealing members formed around the manifold and around each flow path on both sides of the bipolar plate. The method of claim 1, A stack of fuel cells, characterized by sealing each manifold and each flow path of adjacent bipolar plates by inserting ring-shaped sealing members integrally formed around the manifold and around the flow paths on both sides of the bipolar plate. The method according to claim 10 or 11, wherein The ring-shaped sealing member is engaged with the ring-shaped sealing member of the neighboring bipolar plate to seal alternately. The method of claim 12, The ring-shaped sealing member is a stack of fuel cells, characterized in that to engage the electrolyte membrane between the ring-shaped sealing member of the neighboring bipolar plate. The method of claim 1, The fuel supply tube is connected to the fuel passage of the end plate so that fuel is supplied upward from the fuel passage of the bipolar plate while the air supply tube is connected to the air passage of the end plate so that the air is supplied downward from the air passage of the bipolar plate. A stack of fuel cells, characterized in that.

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