JPH06333582A - Solid polyelectrolyte fuel cell - Google Patents

Abstract

(57) [Abstract] [Objective] While maintaining the high efficiency of the solid polymer electrolyte fuel cell, the concentrated stress applied to the electrolyte membrane is reduced, and the electrolyte membrane is formed by the pressure difference between the fuel gas and the oxidant gas. Provided is a solid polymer electrolyte fuel cell capable of reducing the occurrence of breakage. [Structure] A unit cell 1 of a solid polymer electrolyte fuel cell has a fuel electrode 7A and an oxidant electrode 7B as compared with a conventional unit cell.
The spacers 2A and 2B as the space holding means are provided outside the respective outer peripheries.
Spacers 2A, 2B, respectively than the thickness of the fuel electrode 7A or oxidant electrode 7B 0,05 mm and thin thickness (T _3), has a (T _4), a separator 6A,
6B, side surfaces 6Aa, 6B on the side facing the fuel cell 7
It is interposed between a portion of a, which does not face the fuel electrode 7A or the oxidizer electrode 7B, and each main surface of the electrolyte membrane 7C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved structure of a solid polymer electrolyte fuel cell in which concentrated stress applied to a solid polymer electrolyte membrane is reduced.

[0002]

2. Description of the Related Art As fuel cells, various types of fuel cells such as solid polymer electrolyte type, phosphoric acid type, molten carbonate type, and solid oxide type are known, depending on the type of electrolyte used therein. Among them, the solid polymer electrolyte fuel cell shows a low resistivity when it is saturated with a polymer resin membrane having a proton (hydrogen ion) exchange group in the molecule, and functions as a proton conductive electrolyte. It is the fuel cell used.

FIG. 4 is a side sectional view schematically showing a unit cell of a conventional solid polymer electrolyte fuel cell in a developed state. In FIG. 4, reference numeral 7 is a fuel battery cell including an electrolyte layer 7C, a fuel electrode (also serving as an anode electrode) 7A, and an oxidant electrode (also serving as a cathode electrode) 7B. The electrolyte layer 7C is a thin solid polymer electrolyte membrane (hereinafter, may be abbreviated as PE membrane) in a rectangular shape.
It consists of The fuel electrode 7A is an electrode that is stacked in close contact with one main surface of the PE film 7C and receives supply of a fuel gas (for example, hydrogen or a gas containing hydrogen at a high concentration). The oxidizer electrode 7B is a PE film 7C.
Is an electrode that is intimately stacked on the other main surface of the electrode and is supplied with an oxidizing gas (for example, air). The outer surface side of the fuel electrode 7A is one side surface 7a of the fuel cell unit 7.
The outer surface side of the oxidizer electrode 7B is the fuel cell 7
It is the other side surface 7b. The fuel electrode 7A and the oxidant electrode 7B both have respective catalyst layers containing a catalyst active material,
A porous electrode substrate that supports this catalyst layer, supplies and discharges a reaction gas (hereinafter, fuel gas and oxidant gas are collectively referred to as such), and has a function as a current collector. And the catalyst layer is placed on both main surfaces of the PE film 7C by hot pressing. The fuel electrode 7A and the oxidant electrode 7B
As shown in FIG. 4, the outer dimension of the PE film 7C is smaller than the outer dimension of the PE film 7C. Therefore, the end portions of the fuel electrode 7A and the oxidant electrode 7B and the PE film 7C end. An exposed surface of the PE film 7C having a dimension W as shown in FIG. In the case shown in FIG. 4, both the fuel electrode 7A and the oxidizer electrode 7B have the same outer dimensions in the same plane direction.

Further, 6A is made of a gas impermeable material and is disposed on one side surface 7a of the fuel cell 7 to allow a fuel gas (not shown) to flow to one side thereof and to consume unconsumed gas. A plurality of concave grooves (gas distribution grooves) 61A provided at the same intervals for discharging the hydrogen-containing fuel gas, and a convex partition wall 62A interposed between the gas distribution grooves 61A, The separators are alternately formed. 6B is disposed on the other side surface 7b side of the fuel cell unit 7 and has the same interval for discharging an oxidant gas not shown in the drawing while allowing an oxidant gas not shown to flow therethrough. A plurality of concave grooves (gas distribution grooves) 61B, and the gas distribution grooves 61B.
The convex partition walls 62B interposed between B are formed alternately with each other, and like the separator 6A, are separators made of a gas impermeable material.

The tops of the convex partitions 62A and 62B are formed so as to be flush with the side surfaces 6Aa and 6Ba of the separators 6A and 6B facing the fuel cells, respectively. The side surface 6Aa of the separator 6A is brought into close contact with the side surface 7a of the fuel cell 7, and the separator 6B has the side surface 6Ba of the side surface 7a of the fuel cell 7.
The fuel cells 7 are arranged so as to be in close contact with the fuel cell 7b.

Further, 71 is a separator 6A, 6B.
Of the reaction gas flowing through the gas flow grooves 61A, 61B of
A gas seal body having a function of preventing leakage to the outside of the flow path, and between the exposed surface portion of the dimension (W) which is the peripheral edge portion of each separator 6A, 6B and the peripheral edge portion of the fuel cell unit 7. It will be placed in a vacant space. Furthermore, as shown in FIG. 4, the separators 6A and 6B have outer dimensions in the plane direction larger than those of the fuel electrode 7A and the oxidizer electrode 7B. In the case described above, the separators 6A and 6B are the PE film 7C.
It has the same external dimension in the surface direction as the external dimension in the surface direction.

In many cases, the thickness of the fuel cell 7 is 1 [mm] or less, and the larger the area, the lower the manufacturing cost. Therefore, the largest area possible, for example, 1 [mm] m ² ]. Further, in that case, the thickness dimension of the fuel electrode 7A constituting the fuel cell 7; T ₁ , the thickness dimension of the oxidizer electrode 7B; T ₂ , and the thickness dimension of the PE film 7C; T ₀ are The thickness dimension (T ₁ ) and the thickness dimension (T ₂ ) are 0.3 mm to 0.
It is about 4 [mm], and the thickness dimension (T ₀ ) is about 0.1 [mm] to 0.2 [mm]. further,
The thickness dimension of the unit cell 5 including the fuel cell 7 and the separators 6A and 6B arranged so as to sandwich the fuel cell 7 is as follows.
Usually, it is about 10 mm.

The voltage generated by one fuel battery cell 7 is
Since the value is as low as about 1 [V] or less, a large number of the unit cells 5 having the above-mentioned configuration are connected in series with each other through each fuel cell 7 and the separators 6A and 6B inserted therein. It is generally configured as a fuel cell integrated body (hereinafter, may be abbreviated as a stack), and is generally put to practical use by increasing the voltage.

FIG. 5 is a schematic diagram showing a stack of a solid polymer electrolyte fuel cell. In FIG.
Reference numeral 8 is a stack of a plurality of unit cells 5, and current collector plates 81a and 81b for collecting direct current electricity generated in the fuel cells 7 of the plurality of unit cells 5 at both ends thereof, the unit cells 5 and a collector plate. Both sides of the laminated body in which the electric insulating plates 82a and 82b for electrically insulating the electric plates 81a and 81b from the structure, the unit cells 5, the current collecting plates 81a and 81b, and the electric insulating plates 82a and 82b are laminated. Tightening plate 83a arranged at the end,
83b and a tightening bolt 84 for applying an appropriate pressing force to the tightening plates 83a and 83b, and in addition to these, a cooling body 85 that is inserted every time a plurality of unit cells 5 are stacked. It is a polymer electrolyte fuel cell stack. In the stack 8 configured in this way, the separators 6A and 6B are arranged such that the flow direction of the reaction gas flowing through the gas flow grooves 61A and 61B is the gravity direction on the supply side as indicated by the arrow in FIG. On the upper side, the discharge side is arranged on the lower side with respect to the gravity direction.

In the fuel cell 7, when generating direct current electricity, which will be described later, a loss equivalent to the amount of electric power generated is generated. The role of the cooling body 85 is to remove the heat due to this loss. A coolant such as water or air (not shown) for removing heat is passed through the cooling body 85 to keep the fuel cell unit 7 at an appropriate temperature described later. Therefore,
In the stack 8 having the configuration shown in FIG. 5, the separators 6A and 6B prevent the permeation of the reaction gas, and the flow passages of the reaction gas to be supplied to the fuel cell 7 are formed by the gas circulation grooves 61A and 61B. The heat generated by the direct current electricity generated in the fuel cell unit 7 and the loss generated in the fuel cell unit 7 is transmitted to the current collector plates 81a, 81b and the cooling body 85 through the convex partition walls 62A, 62B while being secured. The role to do is also fulfilled. In order to surely achieve these roles, the materials used for the separators 6A and 6B are
It is necessary to have the following properties. That is, the electric resistance value is small. Small thermal resistance value. The contact electric resistance value and the contact thermal resistance value are small at the contact portion with the fuel electrode 7A or the oxidizer electrode 7B. High corrosion resistance. Is.

Materials satisfying these various conditions are:
Although carbon or a special metal such as titanium or niobium can be used as a candidate, carbon is often used as the material for the separators 6A and 6B from the viewpoints of workability and material cost. The material of the separators 6A and 6B using carbon is that fine carbon particles are sintered to obtain a plate-like body first, and the pores formed between the carbon particles of the porous plate-like body thus obtained are formed. A resin impregnated with a filling agent such as phenol resin is generally used. This treatment of the filling agent is performed to fill the pores formed between the carbon particles of the porous flat plate-like body and prevent the reaction gas from leaking out through the separators 6A and 6B. It is something that will be done. The carbon porous flat plate body thus treated with the packing material is processed to form the gas distribution grooves 61A and 61B, and the separator 6 is formed.
It serves as A and 6B.

Further, in the stack 8, the fuel cell 7
Since the electrical resistance and thermal resistance between the battery and the current collectors 81a and 81b and the cooling body 85 are suppressed to be small, the characteristics of the fuel cell are improved. In order to reduce the pressure, the tightening bolt 84 applies pressure so that a constant pressure is always applied. Generally, this pressure is about several kg / cm ² .

In the stack 8 having the above structure, the fuel electrode 7A and the oxidant electrode 7B respectively provided in the plurality of fuel cells 7 are supplied with fuel gas and the oxidant electrode 7B with fuel gas. By supplying the oxidant gas, a three-phase interface (the catalyst in the catalyst layer, the PE film, and either reaction gas) is formed at the interface between the catalyst layer of each of the electrodes 7A and 7B and the electrolyte layer 7C made of the PE film. Means an interface contacting each other), and direct current electricity is generated by causing an electrochemical reaction. The catalyst layer is
It is formed from a fine particulate platinum catalyst and a fluororesin with water repellency, and by forming a large number of pores, while maintaining efficient diffusion of the reaction gas to the three-layer interface, The three-layer interface having a sufficiently large area is formed.

By the way, P forming the electrolyte layer 7C
As described above, the E membrane is a polymer membrane having a proton (hydrogen ion) exchange group in the molecule, and shows a resistivity of 20 [Ω · cm] or less at room temperature when it is saturated with water and exhibits a proton conductive electrolyte. It is a film that functions as. The saturated water content of this PE membrane reversibly changes with temperature. In addition,
As the PE film, at present, a perfluorosulfonic acid resin film (for example, Nafion film manufactured by DuPont, USA) is known. The electrochemical reaction that occurs at the three-phase interface formed by the electrolyte layer 7C using such a PE film, the catalyst layer, and the reaction gas is as follows.

At the anode electrode 7A, the reaction of the formula (1) occurs.

[0016]

[Equation 1]

At the cathode electrode 7B, the reaction of the formula (2) occurs.

[0018]

[Equation 2]

That is, at the anode electrode 7A, hydrogen supplied from the outside produces protons and electrons. The generated protons pass through the PE film 7C into the cathode electrode 7
The electrons move toward B and move to the cathode electrode 7B through an external electric circuit (not shown). On the other hand, in the cathode electrode 7B, oxygen supplied from the outside reacts with the protons moving from the anode electrode 7A in the PE film 7C and the electrons moving from the external electric circuit to generate water. Thus, the fuel cell 7 obtains hydrogen and oxygen to generate direct current electricity. In such a solid polymer electrolyte fuel cell, in order to reduce the resistivity of the PE film 7C and obtain high power generation efficiency, a temperature condition of about 50 [° C.] to 100 [° C.] is usually used. Be driven in. Since the PE film 7C is also a film that does not allow the reaction gas such as the fuel gas and the oxidant gas to pass through, it also plays the role of preventing so-called cross leak in which the reaction gases are mixed with each other.

Further, as the separator, in addition to the separators 6A and 6B in which the groove 61A or the groove 61B is arranged on only one side surface, the grooves of the separators adjacent to each other in the stack structure are also integrally formed. By doing so, in order to rationalize the stack configuration, the gas flow groove 6
There is also known a separator in which 1A and 61B are arranged on both side surfaces thereof.

[0021]

In the solid polymer electrolyte fuel cell using the separator according to the above-mentioned conventional technique, the function of direct current power generation is sufficiently exhibited.
There are the following problems. That is, the PE film 7C, which is the electrolyte of the solid polymer electrolyte fuel cell, has the property that creep occurs when pressure is continuously applied and the film thickness thereof decreases. In particular, when the operating temperature is high, when the film contains sufficient water, when high pressure is applied to a small area, the creep progresses rapidly. As described above, the solid polymer electrolyte fuel cell is operated in a state where the operating temperature is raised and the PE film 7C sufficiently contains water, so that the PE film 7C is placed in a state where creep easily occurs. Will be.

Furthermore, in the conventional solid polymer electrolyte fuel cell, the convex partition walls 62A and 62B of the separator 6A and the separator 6B constituting the unit cell 5 are as shown in FIG.
As shown in the figure, the fuel cells 7 are arranged so as to face each other. As a result, the PE film 7C located at the position sandwiched by the tops of the convex partition walls 62A and 62B is pressed from both sides of the film at the tops via the fuel electrode 7A and the oxidizer electrode 7B to apply a concentrated load. Upon receiving it, creep occurs, which may reduce the film thickness. PE film 7
When the film thickness decreases in C, the tensile strength of the PE film 7C decreases at that portion, and when the fuel cell is operated for a long time, PE becomes due to the pressure difference between the fuel gas and the oxidant gas at this portion.
In some cases, the membrane 7C was damaged, making it impossible to continue the operation of the fuel cell as illustrated in FIG.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to reduce the concentrated stress applied to the PE membrane while maintaining the high efficiency of the solid polymer electrolyte fuel cell. Another object of the present invention is to provide a solid polymer electrolyte fuel cell that can reduce the occurrence of damage to the PE membrane due to the pressure difference between the fuel gas and the oxidant gas.

[0024]

SUMMARY OF THE INVENTION In the present invention, the above-mentioned objects are as follows: 1) A fuel battery cell for receiving a supply of a fuel gas and an oxidant gas to generate DC power, and arranged on both sides of the fuel battery cell. A fuel cell having a separator having a plurality of gas flow grooves for supplying a fuel gas or an oxidant gas to the fuel cell, the fuel cell having an electrolyte layer made of a PE film and two main surfaces of the PE film. And an electrode having an outer dimension in the plane direction smaller than the outer dimension in the plane direction of the PE film, and the separator is on a side surface facing the fuel cell, A plurality of concave grooves for gas flow and a convex partition wall interposed between the concave grooves adjacent to each other are formed, and the external dimension in the surface direction larger than the external dimension in the surface direction of the electrode. Is to have, In the solid polymer electrolyte fuel cell,
The side surface of the separator facing the fuel cell, PE
The structure is provided with a space holding means for holding the space dimension between the main surface of the membrane and 2) In the means described in the above item 1, the space holding means is opposed to the fuel cell of the separator. The side surface of the side of the PE film, which is not facing the electrode, is a spacer interposed between the main surface of the PE film, and 3) in the means described in 1 above. The means can be achieved by a configuration in which the separator is a protrusion formed on a side surface of the separator on the side facing the fuel cell, the side surface not facing the electrode.

[0025]

According to the present invention, in the solid polymer electrolyte fuel cell, for example, between the portion of the side surface of the separator facing the fuel cell and not facing the electrode, and the main surface of the PE membrane. A spacer holding means for holding a gap between the main surface of the PE membrane and the side surface of the separator, such as a spacer, which is in contact with the electrode of the fuel cell, and the main surface of the PE membrane. As a result, the distance between the side surfaces of the two separators on the side in contact with the electrodes of the fuel cells is held at the sum of the thickness of the distance holding means and the thickness of the PE film. As a result, the PE membrane is prevented from being excessively pressed from both sides thereof via the fuel electrode and the oxidizer electrode by the top portions of the convex partition walls of both separators. The excessive creep that was caused by is eliminated.
In addition, when the space holding means is a protrusion formed on a side surface of the separator facing the fuel cell, the side surface not facing the electrode, a spacer is used to achieve the action according to the paragraph. There is no need to prepare separately.

[0026]

Embodiments of the present invention will be described in detail below with reference to the drawings. Embodiment 1; FIG. 1 is a side sectional view schematically showing an unfolded unit cell of a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 1 and 2. The same parts as those of the unit cell of the conventional solid polymer electrolyte fuel cell shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted. Figure 1
In the figure, 1 is a portion outside the outer periphery of the fuel electrode 7A and the oxidizer electrode 7B (or the dimension (W) with respect to the unit cell 5 of the conventional solid polymer electrolyte fuel cell shown in FIG. It can also be said that it is a portion facing the exposed surface portion of the PE film 7C having a spacer. 2A and a spacer 2B as a space maintaining means is provided as a unit cell of the solid polymer electrolyte fuel cell.

The spacer 2A has a thickness dimension; T ₃ ,
Side surface 6 of separator 6A on the side facing fuel cell 7
A portion of Aa facing the exposed surface portion of the PE film 7C,
It is interposed between the PE film 7C and one main surface of the PE film 7C. Further, the spacer 2B has a thickness dimension; T _4, and has a side surface 6Ba on the side of the separator 6B facing the fuel cell unit 7,
A portion of the PE film 7C facing the exposed surface portion, and the PE film 7C.
It is inserted between the other main surface of C.

Here, the thickness dimension (T ₃ ) of the spacer 2A
Is 0.05 than the thickness dimension (T ₁ ) of the fuel electrode 7A.
[Mm] It is thinner, and the thickness dimension (T ₄ ) of the spacer 2B is 0.05 [m] than the thickness dimension (T ₂ ) of the oxidizer electrode 7B.
m] It is set thin. Also, these spacers 2
The materials used for A and 2B are separators 6A and 6B.
It is necessary to have the following properties that are partly common to the properties to be possessed by. That is, the corrosion resistance at the maximum operating temperature condition of the unit cell 1 of the solid polymer electrolyte fuel cell. Heat-resistant. Moderate rigidity. Is equipped with.

By having this condition, the spacer 2
Materials that can be used for A and 2B include carbon, special metals such as titanium, thermosetting synthetic resins, and some thermoplastic synthetic resins having heat resistance (for example, polycarbonate, polyamide, polyether ether, polyether). Sulfone, polyphenylene sulfide, polysulfone, etc.).

A unit cell 1 having the above-described structure is shown in FIG.
In the stack 8 of the solid polymer electrolyte fuel cell illustrated in
By replacing the unit cell 5 of the conventional example in
A polymer electrolyte fuel cell stack is constructed. this
Since the invention has the above-described configuration, the side surface of the separator 6A
The distance between 6Aa and the side surface 6Ba of the separator 6B is
Thickness of pacer 2A (T₃) And the thickness of the spacer 2B
Dimension (T_Four) And the thickness of the PE film 7C (T₀) With
Maintained in Japanese dimensions. By the way, with the conventional stack 8
Similarly, when constructing the stack according to this embodiment,
From fuel cell 7 to current collectors 81a, 81b and cooling body
To keep electrical resistance and heat resistance to 85 low
For example, number (kg / cm²] Tightening
The pressure is applied by the belt 84. However, the above
Of the side surface 6Aa of the separator 6A and the separator 6B.
The distance from the side surface 6Ba is the thickness dimension of the spacer 2A.
(T₃) And the thickness of the spacer 2B (T_Four) And PE
Thickness of the film 7C (T₀) And the total dimensions
In order to ensure that the fuel cell 7
7A thickness (T₁) And the thickness dimension of the oxidizer electrode 7B
(T₂) And the thickness of the PE film 7C (T₀) Total size
Have the law ] Is the thickness of the spacer 2A at that time
Dimension (T₃) And the thickness dimension of the fuel electrode 7A (T ₁) Difference
And the thickness of the spacer 2B (T_Four) And oxidizer electrode
7B thickness (T₂) Is the sum of the difference and
It is only compressed by 0.1 mm.

As described above, the fuel electrode 7A and the oxidizer electrode 7B are both a fine particle platinum catalyst and a catalyst layer having a large number of pores formed from a fluororesin having water repellency, and this catalyst. Since it is composed of a porous electrode base material that supports the layer, it is a member that is relatively easily compressed. Therefore, the compression of 0.1 [mm] generated in the fuel cell 7 during the assembly of the stack is almost absorbed by the compression of the fuel electrode 7A and the oxidant electrode 7B. For this reason, in the case of the stack according to this embodiment, the PE film 7C
Is prevented from being excessively pressed from both sides of the convex partition walls 62A and 62B of the separators 6A and 6B via the fuel electrode 7A and the oxidizer electrode 7B, so that the pressure is applied to both the top parts. It is possible to eliminate the occurrence of excessive creep that has occurred in the PE film 7C due to this.

Embodiment 2; FIG. 2 is a side sectional view schematically showing a unit cell of a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 1 and 3 in a developed state. . The same parts as those of the unit cell of the conventional solid polymer electrolyte fuel cell shown in FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 2, 3 is a solid polymer electrolyte fuel in which the separators 4A and 4B are used instead of the separators 6A and 6B in the unit cell 5 of the conventional solid polymer electrolyte fuel cell shown in FIG. It is a battery cell.

The separator 4A has a portion (or size (W)) on the side surface 6Aa of the separator 6A on the side facing the fuel cell 7 which is not facing the fuel electrode 7A, as compared with the separator 6A shown in FIG. Can also be said to be a portion facing the exposed surface portion of the PE film 7C having a).
A protrusion 41A serving as a space holding means is additionally formed. The protrusion side surface 4Aa of the protrusion 41A
The height dimension of the protrusion from the side surface 6Aa is T ₅ . Further, the separator 4B is different from the separator 6B shown in FIG. 4 in that the side surface 6Ba of the separator 6A on the side facing the fuel cell 7 has a portion (or a dimension (W)) not facing the fuel electrode 7A. It can also be said that it is a portion facing the exposed surface portion of the PE film 7C that it has).
The protrusion 41B as an interval maintaining means is additionally formed so as to protrude from the fuel cell 7 toward the fuel cell 7. The projecting height dimension of the projecting side surface 4Ba of the projecting portion 41B from the side surface 6Ba is T ₆ . The above-described structure of the separators 4A and 4B is
Since 6B uses the material described above, it can be easily realized.

Here, the protrusion height dimension (T
_Five) Is the thickness dimension of the fuel electrode 7A (T₁) Than 0.0
5 [mm] less, and the height of protrusion of protrusion 41B
(T ₆) Is the thickness dimension (T₂)than
It is set to be less by 0.05 [mm]. According to the above
The unit cell 3 having the configuration is shown in FIG.
Conventional unit cell 5 in stack 8 of degradable fuel cell
It can be used as a solid polymer electrolyte fuel cell
Is constructed.

Since the present invention has the above-mentioned structure, the side surface 6Aa of the separator 4A and the side surface 6B of the separator 4B are included.
The distance from a is determined by the protrusion height dimension (T ₅ ) of the protrusion 41A of the separator 4A, the protrusion height dimension (T ₆ ) of the protrusion 41B of the separator 4B, and the thickness dimension (T ₀ ) of the PE film 7C. )
And the total dimensions are maintained. Therefore, as in the case of the first embodiment, when the stack according to the present embodiment is configured, the distance between the side surface 6Aa of the separator 4A and the side surface 6Ba of the separator 4B is determined by the protrusion height dimension of the protrusion 41A. (T ₅ ) and the protrusion height dimension (T ₆ ) of the protrusion 41B,
Since the PE film 7C is held at the total size with the thickness (T ₀ ) of the PE film 7C, the fuel cell 7 has the protrusion 4 at that time.
The difference between the projected height dimension (T ₅ ) of 1A and the thickness dimension (T ₁ ) of the fuel electrode 7A, the projected height dimension (T ₆ ) of the protruding portion 41B and the thickness dimension of the oxidizer electrode 7B ( It is only compressed by 0.1 mm, which is the sum of the difference from T ₂ ). When assembling this stack, fuel cell 7
Most of the compression of 0.1 [mm] generated in the above is absorbed by the compression of the fuel electrode 7A and the oxidant electrode 7B.

Therefore, in the case of the stack according to this embodiment, the PE film 7C is formed on the convex partition walls 62A and 62B of both separators 4A and 4B via the fuel electrode 7A and the oxidant electrode 7B. Since the top portion does not excessively press from both sides thereof, it is possible to eliminate the occurrence of excessive creep that has occurred in the PE film 7C due to the pressure at both the top portions. .
Further, in order to achieve this, unlike the first embodiment, it is not necessary to separately prepare the spacer.

In the above description of the first and second embodiments,
The thickness of the spacer 2A (T _3), the thickness (T ₄₎ and the projection height of the protrusions 41A of the spacer 2B (T _5), the projecting height of the projecting portion 41B (T _6), respectively both the thickness of the fuel electrode 7A (T ₁₎ and the thickness dimension of the oxidant electrode 7B (T ₂₎ to 0.05 [m
m] Although it is assumed to be small, the present invention is not limited to this. For example, the total dimension of the thickness dimension (T ₃ ), the thickness dimension (T ₄ ), and the thickness dimension (T ₀ ) of the PE film 7C, or , The total height of the protruding height dimension (T ₅ ), the protruding height dimension (T ₆ ), and the thickness dimension (T ₀ ) is 0.1 [mm] smaller than the thickness dimension of the fuel cell unit 7. If so, the thickness dimension (T ₃ ) and the thickness dimension (T ₄ ) or the protrusion height dimension (T ₅ ) and the protrusion height dimension (T ₆ ) do not have to be the same difference dimension. .

Further, in the description so far in Example 1.2, the thickness dimension (T ₃ ), the thickness dimension (T ₄ ), and the PE
The total dimension of the thickness dimension (T ₀ ) of the membrane 7C, or the total dimension of the protruding height dimension (T ₅ ), the protruding height dimension (T ₆ ), and the thickness dimension (T ₀ ) is the fuel cell 7 The thickness is smaller than the thickness of 0.1 mm by 0.1 mm, but the thickness is not limited to this.
The thickness to be made smaller than the thickness dimension may be a dimension corresponding to the amount by which the fuel electrode 7A and the oxidant electrode 7B are compressed by the pressure applied by the tightening bolts 84 at the time of assembling the stack. , The fuel electrode 7A. In the case of 7B, the size to be reduced may be zero. Corresponding to this case, the thickness dimension (T ₃ ), the thickness dimension (T ₄ ), and the PE film 7C The maximum value of the sum of thickness dimensions (T ₀ ), or the protrusion height dimension (T ₅ ), the protrusion height dimension (T ₆ ), and the thickness dimension (T
Maximum value of the sum size of _0), the thickness (T _1), is equal to the sum size of the thickness (T ₂₎ and thickness (T _0).

[0039]

According to the present invention, with the above-mentioned constitution, the PE film is prevented from being excessively pressed from both sides by the top portions of the convex partition walls of both separators. It becomes possible to eliminate the excessive creep that has occurred in the PE film due to the pressing. As a result, the film thickness of the PE film does not decrease at the position of the top of the convex partition wall of the separator, and the tensile strength of the PE film does not decrease at that position. As a result, the solid polymer electrolyte fuel cell can be stably operated for a long period of time without causing damage to the PE membrane at that portion. FIG. 3 shows an example of continuous operation data of a single cell of the solid polymer electrolyte fuel cell using the separator according to the present invention. Unlike the case of the solid polymer electrolyte fuel cell using the separator of the conventional example shown in FIG. 6, it has been confirmed that stable operation is performed for a long period of time, and the effect of the present invention is recognized.

[Brief description of drawings]

FIG. 1 is a side sectional view schematically showing a unit cell of a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 1 and 2 in a developed state.

FIG. 2 is a side sectional view schematically showing a unit cell of a solid polymer electrolyte fuel cell according to an embodiment of the present invention corresponding to claims 1 and 3 in a developed state.

FIG. 3 is a graph showing an example of continuous operation data of a single cell of a polymer electrolyte fuel cell using a separator according to the present invention.

FIG. 4 is a side sectional view schematically showing an unfolded unit cell of a solid polymer electrolyte fuel cell of a conventional example.

FIG. 5 is a schematic configuration diagram of a solid polymer electrolyte fuel cell stack.

FIG. 6 is a graph showing an example of continuous operation data of a single cell of a polymer electrolyte fuel cell using a conventional separator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 unit cell 2A spacing holding means (spacer) 2B spacing holding means (spacer) 3 unit cell 4A separator 4B separator 41A spacing holding means (projection part) 41B spacing holding means (projection part) 6A separator 6Aa side surface 6B separator 6Ba side surface 62A convex -Shaped partition wall 62B Convex partition wall 7 Fuel cell 7A Fuel electrode 7B Oxidizer electrode 7C Electrolyte layer (PE film)

Claims (3)

[Claims] 1. A fuel cell that receives supply of a fuel gas and an oxidant gas to generate DC power, and fuel cells that are arranged on both sides of the fuel cell and that supply the fuel gas or the oxidant gas to the fuel cell. The fuel cell comprises a solid polymer electrolyte membrane, an electrolyte layer, and two main surfaces of the electrolyte layer, which are in close contact with each other. An electrode having an outer dimension in the plane direction smaller than the outer dimension in the plane direction of the layer, wherein the separator has a plurality of concave grooves for gas flow on the side surface facing the fuel cell unit. , A solid polymer electrolyte type, in which a convex partition wall interposed between adjacent concave grooves is formed and has an outer dimension in the plane direction larger than the outer dimension in the plane direction of the electrode. For fuel cells There are, the side of the side facing the fuel cell separator, a solid polymer electrolyte fuel cell characterized by comprising a space holding means for holding the distance dimension between the major surface of the electrolyte layer. 2. The solid polymer electrolyte fuel cell according to claim 1, wherein the space holding means comprises a separator, a side surface of the separator facing the fuel cell, a portion not facing the electrode, and an electrolyte layer. A solid polymer electrolyte fuel cell, which is a spacer inserted between the main surface and the main surface. 3. The solid polyelectrolyte fuel cell according to claim 1, wherein the space holding means is a protrusion formed on a portion of a side surface of the separator facing the fuel cell, the side surface not facing the electrode. The solid polymer electrolyte fuel cell is characterized by: