JPH09266007A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight and small fuel cell in which a surface contact force is kept appropriately to reduce electric and thermal surface resistance so as to prevent mixing of fuel with an oxidizer and leaking of the fuel and the oxidizer out of a single cell and in which end plates are made thinner and smaller. SOLUTION: A clamping rod 6 has a cooling water passage pipe 7, an oxidizer passage pipe 8, and a fuel passage pipe 9, through which cooling water, an oxidizer, and fuel, respectively, flow to the circulating part of the clamping rod 6, with the inlet and outlet of each pipe arranged in symmetry with respect to the center O of a clamping plate 4 on a Y-Z plane. The cooling water passage pipe 7 is connected to a cooling plate to supply and collect the cooling water. Similarly, the oxidizer passage pipe 8 supplies and collects the oxidizer to and from an oxidizer electrode, and the fuel passage pipe 9 is connected to a fuel electrode to supply and collect the fuel. A stacked body 1 is supported by such a clamping rod 6, with a spring 10 provided at one end of the clamping rod 6 so that the stacked body 1 is elastically supported on the clamping plate 4. Thus the clamping rod 6 serves also as the pipe through which a coolant and the like circulates and the pipe elastically supporting the stacked body 1, so that the fuel cell can be made smaller and lighter.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel cell.

[0002]

2. Description of the Related Art A fuel cell is a cell that directly converts chemical energy into electric energy. Specifically, gas of light oil or industrial fuel and oxygen cause a chemical reaction in an electrolyte, and as a part of it, electric power is generated. Is generated.

Among fuel cells, a polymer electrolyte (polymer electrolyte) having hydrogen ion conductivity is used as an electrolyte.
polymer electrolyte fuel cell PEFC (Poly
Electrolyte Fuel Cell) is gaining attention as a power source for space and vehicles, because it is compact, has high output (high current density), and can be operated with a simple system.

Known polymer electrolyte membranes include polystyrene-based cation exchange membranes having sulfonic acid groups, mixed substances of fluorocarbon sulfonic acid and polyvinylidene fluoride, and grafted trifluoroethylene on a fluorocarbon matrix. ing. Recently, a perfluorocarbon sulfonic acid membrane (trade name; Nafion: manufactured by DuPont) is used.

The structure of a conventional fuel cell will be described below with reference to the drawings. FIG. 4 is an exploded perspective view of the stack, and FIG. 5 is a perspective view of the fuel cell. For example, the fuel electrode 101 made of platinum and the oxidant electrode 102 made of platinum sandwich the polymer electrolyte membrane 103, and the electromotive portion 1 of the fuel cell is formed.
Make up 04. The fuel distribution plate 105 is provided on the fuel electrode 101.
However, the oxidant distribution plate 106 is bonded to the oxidant electrode 102. On the surface of the fuel distribution plate 105 in contact with the fuel electrode 101, a groove 107 serving as a fuel flow path is provided with an oxidizer distribution plate 106.
A groove 108 that serves as an oxidant flow path is provided on the surface that contacts the oxidant electrode 102. The fuel distribution plate 105 and the oxidant distribution plate 106 are current collectors. In addition, the polymer electrolyte membrane 10
The sheet packing 10 in which a hole cut out in the shape of the oxidizer electrode 102 is formed between the oxidizer distributor 3 and the oxidizer distribution plate 106.
9 is narrowed down. The fuel distribution plate 105 includes a cooling plate 110.
Are adhered. The cooling plate 110 is configured by laminating a humidification water transmission plate 111 and a cooling water distribution plate 112. A groove 113 through which cooling water can flow is provided on the surface of the cooling water distribution plate 112 on the humidification water transmission plate 111 side.

Further, the single cell 114 is composed of the oxidant distributor plate 10.
6, a sheet packing 109, an oxidizer electrode 102, a polymer electrolyte membrane 103, a fuel electrode 101, and a fuel distribution plate 105 are laminated in this order.

The cooling plate 110 is inserted between the single cell 114 and the adjacent single cell 114, and these are laminated to form a laminated body 115. Oxidizer distribution plate 106, sheet packing 109, polymer electrolyte membrane 103, and fuel distribution plate 1
05, the humidification water permeation plate 111, and the cooling water distribution plate 112 are provided with a plurality of holes 116 that pass through in common. Fuel, an oxidizer, and cooling water are circulated through the holes 116.
The fuel distribution plate 105, the oxidizer distribution plate 106, the humidification water permeation plate 111, and the cooling water distribution plate 112 are provided with communication grooves 117 serving as inlets and outlets of fuel, oxidizer, and cooling water.

The sheet packing 109 is a single cell 114.
It is possible to prevent the fuel and the oxidizer from being mixed when they are stacked, and also to prevent the fuel from leaking to the outside of the stacked body 115. It also prevents the fuel distribution plate 105 and the oxidant distribution plate 106 from being electrically short-circuited.

The cooling plate 110 cools the heat generated by the electromotive reaction by circulating water. Laminate 115
The stacked stack 126 is sandwiched by the end plates 118 from both sides thereof. The end plate 118 is provided with a terminal 119 for taking out the generated electric power to the outside of the fuel cell. End plate 1
18 is sandwiched by a tightening plate 120 made of SUS via a sheet of an insulating material (resin such as Teflon), and is fixed integrally by tightening a plurality of tightening rods 121 and springs 122.

End plate 118 and tightening plate 120
And a hole 116 that commonly penetrates through, similarly to the laminated body 115.
Is provided. A pipe 123 through which fuel is supplied to the fuel electrode 101 and through which fuel discharged from the fuel electrode 101 passes through the hole 116.
However, a pipe 124 for supplying and recovering the oxidant to the oxidant electrode 102 is inserted, and a pipe 125 for circulating cooling water is inserted in the cooling plate 110. The arrow in the figure is an example of the flow direction of the medium.

The fuel cell thus constructed is housed in a pressure vessel (not shown) in which an inert gas is sealed. Then, the laminated body 1 including the cooling plate 110 and the single cell 114
The fastening rod 15 and the spring 122 are pressed against each other with a desired contact force so as to reduce the electric resistance and the thermal surface resistance. Then, fuel such as pure hydrogen, natural gas, reformed gas such as methanol, sodium, hydrocarbon, carbon monoxide, etc., oxidant such as pure oxygen, air, etc., and cooling water are supplied to respective parts of the apparatus. The pressures of the fuel, oxidant and coolant at the time of supply are set high, and the operating pressure of the fuel cell is raised to generate electricity.

Further, the fuel cell is arranged in a pressure vessel (not shown) filled with an inert gas. Here, the operating pressure of the fuel cell is the same as the pressure of the inert gas in the pressure vessel in order to prevent the fuel and the oxidant from leaking out from the single cell 114. It is also possible to use hydrogen obtained from caustic soda as a fuel.

[0013]

However, in the fuel cell having the above-mentioned structure, it is necessary to increase the operating pressure of the cell in order to improve the cell performance. It is necessary to increase the thickness of the plate and the tightening plate to increase the rigidity, and also to use a large number of tightening rods and springs, resulting in an increase in size of the device and an increase in weight.

Further, in order to improve the battery performance, it is possible to increase the area of the electromotive portion of the single cell, but there is a problem that the device becomes large and the weight also increases.
Further, it is not easy to make the surface contact force of each constituent element such as the oxidizer electrode constituting the single cell uniform to a desired force,
There were also problems with electrical and thermal properties, and with the mixture of fuel and oxidizer, there were problems such as leakage to the outside of the single cell.

Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, in which the surface contact force is kept good, the electrical / thermal surface resistance is reduced, and the fuel and the oxidizer are mixed. Another object of the present invention is to provide a small and lightweight fuel cell by preventing fuel and oxidant from leaking out of the unit cell and by making the end plate thin and small.

[0016]

In order to achieve the above-mentioned object, a fuel cell of the present invention comprises an oxidant electrode to which an oxidant is supplied, a fuel electrode to which hydrogen gas is supplied, and the oxidant electrode. And a laminated body in which a single cell sandwiched between the fuel electrode and an electrolyte membrane that generates electricity by a chemical reaction between hydrogen gas and an oxidant is alternately laminated with a cooling unit that cools the single cell. A support having a circulation portion that is inserted into a perforated portion provided in the laminated body, supports the laminated body in the laminating direction of the laminated body, and supplies or recovers a fuel or an oxidant to the laminated body. And means.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a fuel cell, and FIG. 2 is a schematic cross-sectional view around a fastening rod of the fuel cell. The arrows in FIGS. 1 and 2 show an example of the flow direction of the cooling water, the oxidant, or the fuel.

The basic structure of the unit cell for generating electricity by the chemical reaction between the fuel necessary for power generation and the oxidant is almost the same as the structure shown in FIG.
The sheet packing, the oxidizer electrode, the polymer electrolyte membrane (electrolyte membrane), the fuel electrode, and the fuel distribution plate are laminated in this order. Further, in the single cell, a portion where the fuel electrode, the polymer electrolyte membrane and the oxidizer electrode are laminated and integrated with each other becomes an electromotive portion.

A stack 1 is constructed by stacking such single cells and inserting a cooling plate (cooling section) consisting of a humidifying water permeation plate and a cooling water distribution plate between adjacent single cells. To do.
The laminated body 1 is sandwiched by the end plates 2 in the laminating direction of the laminated body 1, and a part of the end plate 2 is provided with a terminal 3 for taking out electric power generated by a chemical reaction. On the outside of the end plate 2, a tightening plate 4 (holding part) made of an insulating material is provided.

The end plate 2, the tightening plate 4, and the oxidant distribution plate, sheet packing, polymer electrolyte membrane, fuel distribution plate, humidifying water permeation plate, and cooling water distribution plate that constitute the laminate 1 are common to each other. A plurality of through holes 5 (piercing portions) are evenly formed around the electromotive portion (the through holes 5 in FIG.
mouth).

A cylindrical tightening rod 6 (supporting means) made of SUS is inserted into the through hole 5. The tightening rod 6 includes a cooling water flow path pipe 7 through which cooling water flows, a oxidant flow path pipe 8 through which an oxidant flows, in a medium circulating portion of the tightening rod 6.
There is a fuel flow tube 9 through which the fuel flows. Supply pipe 11 for each pipe
The (supply side) and the recovery pipe 13 (recovery side) are arranged symmetrically with respect to the central portion O (center) on the YZ plane of the fastening plate 4. The cooling water flow path pipe 7 is connected to a cooling plate to supply and collect cooling water. Similarly, the oxidant flow pipe 8 supplies and collects the oxidant to the oxidant electrode, and the fuel flow pipe 9 is connected to the fuel electrode and supplies and collects the fuel.

A spring 10 is provided at one end of the tightening rod 6 to elastically support the laminated body 1 with respect to the tightening plate 4. Next, a detailed configuration of the tightening rod 6 will be described (see FIG. 2).

A supply port 11 for cooling water (or fuel or oxidant) is provided at one end of the tightening rod 6.
A spring 10 spirally wound around the tightening rod 6 is provided at the other end, and elastically supports the laminated body 1 with respect to the tightening plate 4. Further, the medium circulating portion of the tightening rod 6 is
It is a communication part 12 (flow part) through which cooling water (or fuel or oxidant) flows, and is connected to a cooling plate (or fuel electrode or oxidizer electrode) not shown. The cooling water that has circulated through the cooling plate (or the fuel electrode or the oxidizer electrode) is attached to another tightening rod 6 facing the tightening rod 6.
Is connected to the communication part 13 and is connected to the cooling water recovery port 13. A seal member 14 is provided at a portion where the tightening rod 6 contacts the tightening plate 4.

The operation of the fuel cell thus configured will be described. Fuel such as pure hydrogen is supplied to the fuel electrode from the supply pipe 11 of the fuel flow pipe 9 that also serves as the tightening rod 6.
Further, an oxidant such as air is supplied to the oxidant electrode from the supply pipe 11 of the oxidant flow passage pipe 8 which also serves as the tightening rod 6. The supplied air and pure hydrogen cause a chemical reaction in the polymer electrolyte membrane to generate water. Direct current electricity generated by the chemical reaction is sent to an orthogonal converter (not shown) that converts direct current electricity into alternating current. After the chemical reaction, the fuel and oxidant are
The fuel flow pipe 9 or the recovery pipe 13 of the oxidant flow pipe 8 discharges the laminate 1 to the outside.

At this time, the temperature of the single cell due to the chemical reaction is 1
Raise the temperature to about 00 ° C. In order to cool the temperature of the raised single cell, the cooling water flows from the supply pipe 11 of the cooling water flow passage pipe 7 which also serves as the tightening rod 6 to the cooling plate, takes heat from the single cell and cools it, and the recovery pipe 13 And is discharged to the outside of the laminated body 1.

As described above, according to the first embodiment, the oxidant distribution plate, the sheet packing, the polymer electrolyte membrane, the fuel distribution plate, the humidification water permeation plate, and the cooling water distribution plate have through-holes that commonly penetrate therethrough. 5 is provided with a tightening rod 6 having an inlet and an outlet for fuel, oxidant, and cooling water, and the spring 10 is used to tighten the whole body from both sides, so that the laminated body 1 is securely and uniformly tightened with a desired contact force. Therefore, the sealing performance is significantly improved and, for example, the fuel performance and the oxidizer are not mixed so that the battery performance is not deteriorated.

Further, since the periphery of the electromotive portion of the unit cell is evenly tightened, the fuel and the oxidizer are surely prevented from leaking out of the stack, and good surface contact between the stacked cell parts is maintained, The electrical and thermal surface resistance can be reduced and the performance of the fuel cell can be improved.

Further, since the inlet and outlet of the medium flowing through the tightening rod 6 are arranged symmetrically with respect to the central portion O, for example, the fuel supplied to the fuel electrode can permeate the entire fuel electrode. Therefore, a chemical reaction occurs in the entire fuel electrode, resulting in high efficiency and high output of the fuel cell.

Further, since the tightening structure such as the tightening rod 6 and the spring 10 also serves as each flow path tube, the tightening plate 4
The size (area of the YZ plane) can be made small, and the tightening plate 4 can be made thin. This makes it possible to reduce the size and weight.

Further, by providing each passage pipe of the fuel, the oxidizer or the cooling water in the tightening rod 6, the fuel cell can be made compact and lightweight and the cost can be reduced.
Further, the area of the unit cell can be increased to increase the amount of power generation.

Next, the configuration of the second embodiment of the present invention will be described with reference to the drawings. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted.

FIG. 3 is a sectional view of a second embodiment of the fuel cell. The feature of the second embodiment is that a supply unit 18 that supplies cooling water (or fuel or oxidizer) to the stack 1 and a recovery unit 19 that recovers cooling water (or fuel or oxidizer) from the stack 1. Since they are provided in the same tightening rod 6, the number of tightening rods 6 can be reduced, and the size and weight can be reduced.

A groove 16 through which cooling water circulates is provided in the cooling section 15 of the laminate 1, and a cooling section frame 17 is provided on the outer periphery of the cooling section 15. The cooling part frame 17 is provided with a cooling water passage pipe 7 that has both a supply part 18 that supplies cooling water to the groove 16 and a recovery part 19 that recovers the cooling water.

The operation of the fuel cell having such a structure will be described. Due to the chemical reaction between the fuel and the oxidant that occurs in the unit cell, the temperature of the unit cell is about 100 ° C. The groove 1 of the cooling unit 15 for cooling the heat generated from the single cell
Cooling water is circulated in 6 for cooling. The circulation of cooling water is
The cooling water circulates in the order of the supply part 18, the groove 16 and the recovery part 19 in the cooling water flow path pipe 7 which also serves as the tightening rod 6, and the groove 16
The heat of the single cell is absorbed from the cooling unit 15 when passing through the.

As described above, according to the second embodiment, the oxidant distribution plate, the sheet packing, the polymer electrolyte membrane, the fuel distribution plate, the humidification water permeation plate, and the cooling water distribution plate are commonly penetrated. 5 is provided with a tightening rod 6 having an inlet and an outlet for fuel, oxidant, and cooling water, and the spring 10 is used to tighten the whole body from both sides, so that the laminated body 1 is securely and uniformly tightened with a desired contact force. Therefore, the sealing performance is significantly improved, and, for example, the fuel and the oxidant are not mixed with each other and the cell performance is not deteriorated.

Further, since the periphery of the electromotive portion of the single cell is evenly tightened, it is possible to reliably prevent the fuel and the oxidizer from leaking out of the stack, and to keep the surface contact between the stacked cell parts in good condition. The electrical and thermal surface resistance can be reduced and the performance of the fuel cell can be improved.

Further, since the tightening structure such as the tightening rod 6 and the spring 10 also serves as each flow path tube, the tightening plate 4
The size (area of the YZ plane) can be reduced, and the tightening plate 4 can be thinned. This makes it possible to reduce the size and weight.

Further, when the cooling water or the fuel flows through the laminated body 1, two pipes for supplying the cooling water or the fuel into the laminated body 1 and a pipe for collecting the cooling water form one set to form each flow passage pipe. Since it is not necessary to configure and supply and recovery can be performed by one pipe, the area occupied by the flow path pipe in the laminated body 1 can be reduced and the size and weight can be reduced. Further, if the area of the electromotive portion is increased by the decreasing area of the flow passage tube, the battery capacity is improved.

Further, by circulating the cooling water through the groove 16 in the cooling section 15, the heat of the laminate 1 can be efficiently cooled. Needless to say, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, as for the number and shape of each flow tube, at least the medium flowing through each flow tube should circulate. Further, the shape of the groove may be at least that the medium flowing through the groove circulates.

[0040]

As described above, according to the present invention, the surface contact force of each component constituting the manifold is kept good, the electrical / thermal surface resistance is reduced, and the fuel and the oxidant are mixed. It is possible to reduce the size and weight of the fuel cell and the oxidizer by preventing them from mixing with each other and leaking the fuel and the oxidizer to the outside of the single cell and by making the end plate thin and small.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of a fuel cell of the present invention.

FIG. 2 is a schematic cross-sectional view around a tightening rod of the first embodiment of the fuel cell of the present invention.

FIG. 3 is a sectional view of a second embodiment of the fuel cell of the present invention.

FIG. 4 is an exploded perspective view of a conventional laminated body.

FIG. 5 is a perspective view of a conventional fuel cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminated body 2 End plate 3 Terminal 4 Tightening plate (clamping part) 5 Through hole (piercing part) 6 Tightening rod (supporting means) 7 Cooling water flow pipe 8 Oxidizer flow pipe 9 Fuel flow pipe 10 Spring 11 Supply Port (supply side) 12 Communication part (circulation part) 13 Recovery port (recovery side) 14 Seal member 15 Cooling part 16 Groove 17 Cooling part frame 18 Supply part 19 Recovery part

Claims (2)

[Claims] 1. An oxidant electrode supplied with an oxidant, a fuel electrode supplied with hydrogen gas, and an oxidant electrode sandwiched between the oxidant electrode and the fuel electrode, and the hydrogen gas and the oxidant chemically react to generate electricity. A laminated body in which a single cell composed of an electrolyte membrane that generates a layer is alternately laminated with a cooling unit that cools the unit cell, and a perforated portion provided in the laminated body, and the laminated body is laminated. 1. A fuel cell, comprising: a supporting unit that supports the laminate in a direction, and has a circulation unit that supplies or recovers a fuel or an oxidant to the laminate. 2. The supporting means comprises a supply side for supplying fuel, oxidant or cooling water to the laminate, and a recovery side for recovering the supplied fuel, oxidant or cooling water from the laminate. 2. The fuel cell according to claim 1, wherein the supply side and the recovery side are symmetrically arranged with respect to the center of a sandwiching part that sandwiches the laminated body.