JPH0646571B2 - Fuel cell - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fuel cell used in an energy sector for directly converting chemical energy of a fuel into electric energy, and more particularly, to an oxygen electrode and a fuel on both sides of an electrolyte plate. The present invention relates to an internal manifold type fuel cell having a gas inlet / outlet portion that allows an oxidizing gas to flow between an electrode and an oxygen electrode and a fuel gas to flow toward a fuel electrode.

[Prior Art] In a fuel cell, an electrolyte plate is sandwiched by an oxygen electrode and a fuel electrode from both sides, and by supplying an oxidizing gas and a fuel gas to each electrode, a potential difference is generated between the oxygen electrode and the fuel electrode. The unit configured to generate power is laminated in a plurality of layers via a separator.

Conventionally, such a fuel cell is divided into a cross-flow type, a counter-flow type, and a parallel-flow type fuel cell depending on the flow types of an oxidizing gas that is supplied to the oxygen electrode side across the electrolyte plate and a fuel gas that is supplied to the fuel electrode side. It was being done.

As shown in FIG. 4, the parallel flow type fuel cell has a structure in which a unit in which an electrolyte plate 1 is sandwiched by an oxygen electrode 2 and a fuel electrode 3 from both upper and lower surfaces is laminated with a separator 4 interposed therebetween. Gas OG supplied to the oxygen electrode 2 side of
The gas passages 5 and 6 of the separator 4 are oriented so that the fuel gas FG supplied to the side of the fuel electrode 3 and the fuel gas FG supplied to the side of the fuel electrode 3 flow in parallel in the same direction across the electrolyte plate 1, and the oxidation that flows through the separator 4 is also determined. The gas OG and the fuel gas FG also flow in the same direction as above.

Therefore, in the conventional parallel flow type fuel cell, the electrolyte plate 1 and the separator 4,
The electrodes 2 and 3 are prevented from being excessively pressed against the electrolyte plate 1 by the separator 4, and the oxidizing gas OG and the fuel gas FG are also prevented.
On both sides of each of the oxygen electrode side spacer 7 and the fuel electrode side spacer 8 for allowing the gas to flow along both sides of the separator 4, the supply passage hole 9 for the oxidizing gas OG and the supply passage hole for the fuel gas FG. Only 10 are provided alternately at appropriate intervals, and on the other side of the peripheral portion, only the exhaust gas passage holes 11 for oxidizing gas OG and the exhaust gas passage holes 12 for fuel gas FG are alternately provided at appropriate intervals. . Furthermore, in order to supply and discharge the oxidizing gas OG and the fuel gas FG to both surfaces of each separator 4 in each layer, all the oxidizing gas supply flow path holes 9 and 9 provided in the oxygen electrode side spacer 7 of each layer and A notch is provided in each oxidizing gas discharge passage hole 11
13, 14 are provided so that at the oxygen electrode side spacer 7, only the oxidizing gas OG on the supply side is entirely introduced into the gas passage 5 of the separator 4 and then discharged to the discharge flow path hole 11. Similarly, notches 15 and 16 are provided in all the fuel gas supply passage holes 10 and each fuel discharge passage hole 12 provided in the fuel electrode side spacer 8 of each layer, and the fuel gas is provided in the fuel electrode side spacer 7 at the location. Only FG is made to flow from all the supply flow passage holes 10 to all the discharge flow passage holes 12.

[Problems to be Solved by the Invention] However, in the parallel flow type fuel cell, while the oxidizing gas OG and the fuel gas FG sandwich the separator 4 and the electrolyte plate 1 and flow in parallel from the supply side to the discharge side, the separator 4 There is almost no temperature difference between the oxidizing gas and the fuel gas through the heat exchange through the electrolyte gas, and the heat generated from the electrolyte plate 1 as it progresses in the flow direction causes the electrolyte plate (the electrodes to have almost the same temperature), the oxidizing gas, the fuel gas, and Each temperature of the separator increases uniformly,
On the entire flat surface of the electrolyte plate 1, a high temperature portion is generated on the discharge side of both gases, the temperature is low on the inlet side of both gases, and the temperature is high on the discharge side. Along with this, the generated current density distribution cannot be made uniform over the entire surface of the electrolyte plate, resulting in a decrease in efficiency.
When a large temperature gradient occurs on the inlet side and the discharge side of the electrolyte plate as described above, the thermal stress of the electrolyte plate is large and the life is shortened.

Therefore, in order to solve such a problem, the present invention aims to make the temperature distribution uniform in all the planes of the electrolyte plate and to make the temperature distribution uniform, and to make the current density distribution uniform in all the planes of the electrolyte plate. It seeks to obtain performance.

[Means for Solving Problems] In the present invention, both surfaces of the electrolyte plate (1) are provided with an oxygen electrode (2) and a fuel electrode (3).
A single cell configured to sandwich the separator, a gas passage (5) is formed in the central portion of one surface and a separator (4) in which the gas passage (6) is formed in the central portion of the other surface, Electrolyte plate
The peripheral part of (1) and the peripheral part of the separator (4) are laminated so that they are in airtight contact with each other, the electrolyte plate (1), on one side of the peripheral part of the separator (4),
Unreacted oxidizing gas supply channel hole (9) and fuel gas supply channel hole (10) respectively supplied from the outside, oxidizing gas discharge channel hole (11) and fuel gas discharge channel hole (12) and with the electrolyte plate (1), the peripheral portion other side opposite to the peripheral portion one side of the separator (4), the supply flow path hole of the unreacted oxidizing gas supplied from the outside, respectively ( 9) and a fuel gas supply flow path hole (10), an oxidizing gas discharge flow path hole (11) and a fuel gas discharge flow path hole (12) are provided, and the oxidizing gas provided on one side of the peripheral portion is provided. Gas supply channel hole (9)
And the oxidizing gas discharge passage hole (1
1) and the fuel gas supply passage hole (10) provided on one side of the peripheral portion and the fuel gas provided on the other side of the peripheral portion for communicating with the gas passage (5) through the communication passages. A discharge channel hole (12) of the separator (4), which is communicated with the gas channel (6) through a communication channel, respectively, and an oxidizing gas supply channel hole (9) provided on the other side of the peripheral portion. And the oxidizing gas discharge flow passage hole (11) provided on the one side of the peripheral portion are respectively connected to the gas passage (5) through the communication passages and the supply of the fuel gas provided on the other side of the peripheral portion. The separator (4) in which the flow passage hole (10) and the fuel gas discharge flow passage hole (12) provided on one side of the peripheral portion are connected to the gas passageway (6) through the communication passages, respectively. It is characterized in that the cells are sandwiched and arranged alternately.

[Operation] Oxidizing gas and fuel gas that flow across the electrolyte plate (1) go from the supply flow passage holes (9) and (10) at opposite positions along the gas passages (5) and (6) of the separator (4). Is discharged and becomes a counter current. As a result, the reaction between the oxidizing gas and the fuel gas can be kept uniform on all the flat surfaces of the electrolyte plate (1), and the entire surface of the electrolyte plate (1) can be utilized with its maximum performance to obtain a high current density. Further, since the oxidizing gas and the fuel gas that flow through the gas passages (5) and (6) sandwiching the separator (4) are in parallel flow, the entire surface of the electrolyte plate (1) can be made uniform at an optimum temperature.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. Similar to FIG. 5 and FIG. 6, the oxidizing electrode spacer 7 and the fuel electrode side spacer 8 which are space portions by cutting out the central portion corresponding to the electrode are used as the electrolyte. In a fuel cell which is used by interposing between the plate 1 and the separator 4 so that the unevenness of the central portion of the separator 4 does not strongly press the electrodes 2 and 3, the electrolyte plate 1 of each layer, the separator 4, On one side of each peripheral portion of the oxygen electrode side spacers 7a, 7b and the fuel electrode side spacers 8a, 8b,
The oxidizing gas supply flow path hole 9 and the exhaust flow path hole 11, the fuel gas supply flow path hole 10 and the exhaust flow path hole 12 are provided at appropriate intervals, respectively, and the above-mentioned each is also provided on the other side of the peripheral portion facing each other. The flow path holes 9, 11, 10, 12 are provided at appropriate intervals.

Oxidizing gas OG-1, OG-2 flowing through the separator 4 and fuel gas FG-1, FG-2 in parallel flow, and oxidizing gas OG-1, OG-2 flowing through the electrolyte plate 1 And fuel gas FG-1,
It is provided on one side of the peripheral portion of the oxygen electrode side spacer 7a located immediately above the electrolyte plate 1 in order to allow the gases to flow so as to form counter flows that flow in opposite directions to FG-2. And a notch 13 for opening only the oxidizing gas discharge flow path hole 11 in the central space, and an oxidizing gas supply provided on the other side of the peripheral portion facing the one side of the oxygen electrode side spacer 7a. A notch 14 is provided for opening only the flow path hole 9 in the central space, and a fuel gas discharge provided on one side of the peripheral portion of the fuel electrode side spacer 8a located above the oxygen electrode side spacer 7a. A notch 15 is provided for opening only the flow path hole 12 in the central space, and a notch for opening only the fuel gas supply flow path hole 10 provided on the other side of the opposing peripheral part to the central space. 16 is provided. On the other hand, electrolyte plate 1
In the fuel electrode side spacer 8b located immediately below, a notch 16 for opening only the fuel gas supply flow path hole 10 provided on one side of the periphery to the space of the central portion is provided, and on the other side of the opposing peripheral portion. A notch 15 is provided to open only the fuel gas discharge flow path hole 12 provided in the central space, and in the oxygen electrode side spacer 7b located below the fuel electrode side spacer 8b, it is provided on one side of the peripheral portion. Oxidizing gas supply channel hole 9 provided
A notch (14) is provided for opening only the central portion into the central space, and a notch (13) is provided for opening only the oxidizing gas discharge flow path hole (11) provided on the other side of the opposing peripheral portion into the central portion space.

Pipes arranged outside the fuel cell are connected to the oxidizing gas supply passage hole 9 and the exhaust passage hole 11, the fuel gas supply passage hole 10 and the exhaust passage hole 12, respectively.

An unreacted oxidizing gas is introduced from the outside into each oxidizing gas supply passage hole 9 provided at each of the peripheral portions of the electrolyte plate 1, the separator 4, and the spacers 7a, 7b, 8a, 8b facing each other. ,
When an unreacted fuel gas is introduced from the outside into each fuel gas supply passage hole 10, the oxidizing gas OG-1 and the fuel gas FG-2 or the oxidizing gas OG-2 and the fuel flowing through the separator 4 at a certain stage are flown. The gas FG-1 is a parallel flow that flows in the same direction as shown by the arrow, but the oxidizing gas OG-1 and the fuel gas FG-1, which flow through the electrolyte plate 1, or the oxidizing gas OG-2 and the fuel gas FG-2. Are countercurrents flowing in opposite directions. That is, the flow directions of the both gases are as shown in FIG. 2 showing only the gas flows. As a result, the oxidizing gas and the fuel gas flow in opposite directions on both sides of the electrolyte plate 1, so that the fuel gas has a high concentration on the inlet side and a low concentration on the outlet side, while the oxidizing gas enters the same. The concentration is high on the side (that is, the outlet side of the fuel gas) and decreases toward the outlet side (that is, the inlet side of the fuel gas), and it becomes a form in which they complement each other's concentration decrease, The reaction of the oxidizing gas can be made uniform on the entire plane of the electrolyte plate 1, and the separator 4 is sandwiched between the oxidizing gas OG-1.
Alternatively, since the OG-2 and the fuel gas FG-2 or FG-1 flow in parallel, the entire surface of the electrolyte plate 1 can be made uniform at an optimum temperature. As described above, according to the present invention, the features of the counter flow and the features of the parallel flow can be obtained at the same time to obtain the temperature distribution and the current density distribution as shown in FIG. That is, the oxidizing gas OG-1 and the fuel gas FG-2 flowing through one separator 4 are uniformly heated from the inlet a as shown by the curve I. On the other hand, the oxidizing gas OG-2 and the fuel gas FG that flow through the other adjacent separator 4
The temperature of -1 uniformly decreases from the discharge side toward the inlet portion b, as indicated by the curve II, along the flow direction distance X. The temperature of the electrolyte plate 1 is the oxidizing gas that flows across the electrolyte plate 1.
Since the temperatures of OG-1 and fuel gas FG-1 flow opposite to each other, the temperature becomes close to the average temperature of both gases, and a substantially flat temperature distribution can be obtained.

As shown by the curve III, the current density is almost the same as the electrolyte plate temperature because the temperature of the electrolyte plate 1 is uniform and the reaction of the oxidizing gas and the fuel gas is carried out substantially uniformly over the entire plane of the electrolyte plate 1. It becomes a distributed distribution.

In the above, oxidizing gas OG-1, OG-2, fuel gas FG-1, FG
By appropriately selecting the inlet temperature of -2, the entire surface of the electrolyte plate 1 is maintained at its optimum operating temperature, so that the amount of power generation on the entire surface can be maintained at a high value. Further, the electrolyte plate 1, the oxygen electrode 2, the fuel electrode 3 and the separator 4 have substantially uniform temperatures over the entire surface as shown in FIG. 3, and a durable battery is obtained in which thermal stress is unlikely to occur.

The present invention is not limited to the above embodiment. For example, the spacers 7a, 7b, 8a, 8b are used, and the notches 13, 14, 15, 16 are provided in the spacers 7a, 7b, 8a, 8b so that the gas is connected to the gas passages of the separator 4 and the supply flow passage holes and the discharge flow passage holes of each gas. Although the case where it is made to communicate is illustrated, the notch groove may be provided in the separator 4 itself so that each gas flow path hole and the gas passage of the separator may be made to communicate, and the notches 13, 14, 15, 16
Each shape and number of may be other than those shown.

[Effects of the Invention] As described above, according to the fuel cell of the present invention, the separator
In order to regulate the flow directions of the oxidizing gas and the fuel gas flowing along the gas passages (5) and (6) of (4) so that they are different at each stage, the supply flow passage holes (9) (10) for each gas are provided. ) And drainage channel holes (11) (12)
Each gas passage (5) (6) with the separator (4) in between.
The oxidizing gas and fuel gas flowing in the
Since the oxidizing gas and the fuel gas that flow through the gas passages (5) and (6) of the separator (4) across the (1) are in counterflow, the following excellent effects are obtained and obtained.

(i) Since the electrolyte plate (1) is homogenized to the optimum temperature over its entire surface and the reaction between the fuel gas and the oxidizing gas can be homogenized, the entire surface of the electrolyte plate (1) can be used with its maximum performance. ,
High current density can be obtained, and high performance of the fuel cell can be achieved.

(ii) Since the flow rates of the fuel gas and the oxidizing gas can be suppressed to the minimum flow rate required for the reaction for removing the reaction heat generated from the electrolyte plate (1), the power can be reduced and the efficiency can be improved.

(iii) Since the current density is uniform, the wear of the electrolyte plate (1) does not locally increase, and the life of the battery can be extended.

(iv) Electrolyte plate (1), electrodes, separators (4) that make up the battery
Since the temperature distribution of is small, thermal stress is less likely to occur,
Since hot spots are less likely to occur on the electrolyte plate (1), damage to the electrolyte plate (1) is less likely to occur, the performance of the battery can be stabilized, and reliability can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory perspective view showing an embodiment of the present invention, FIG. 2 is a perspective view showing a gas flow obtained by the present invention, and FIG.
FIG. 4 is a diagram showing the distribution of temperature and current density in the case of the gas flow type as shown in FIG. 2, FIG. 4 is a perspective view showing the gas flow of a parallel flow type fuel cell, and FIG. 5 is as shown in FIG. FIG. 6 is a perspective view showing an example of a conventional gas inlet / outlet portion that realizes gas flow, and FIG. 6 is a sectional view of a conventional parallel flow fuel cell. 1 is an electrolyte plate, 2 is an oxygen electrode, 3 is a fuel electrode, 4 is a separator, 7,7a and 7b are oxygen electrode side spacers, 8,8a and 8b are fuel electrode side spacers, 9 is an oxidizing gas supply flow path hole, Reference numeral 10 is a fuel gas supply flow path hole, 11 is an oxidizing gas discharge flow path hole, and 12 is a fuel gas discharge flow path hole.

Claims (1)

[Claims] 1. An oxygen electrode (2) and a fuel electrode on both sides of the electrolyte plate (1).
A single cell configured to intervene in (3), a separator (4) having a gas passage (5) formed in the center of one surface and a gas passage (6) formed in the center of the other surface. The, the peripheral portion of the electrolyte plate (1) and the peripheral portion of the separator (4) are laminated so as to be in airtight contact with each other, the electrolyte plate (1), on one side of the peripheral portion of the separator (4),
Unreacted oxidizing gas supply channel hole (9) and fuel gas supply channel hole (10) respectively supplied from the outside, oxidizing gas discharge channel hole (11) and fuel gas discharge channel hole (12) and with the electrolyte plate (1), the peripheral portion other side opposite to the peripheral portion one side of the separator (4), the supply flow path hole of the unreacted oxidizing gas supplied from the outside, respectively ( 9) and a fuel gas supply flow path hole (10), an oxidizing gas discharge flow path hole (11) and a fuel gas discharge flow path hole (12) are provided, and the oxidizing gas provided on one side of the peripheral portion is provided. Gas supply channel hole (9)
And the oxidizing gas discharge passage hole (1
1) and the fuel gas supply passage hole (10) provided on one side of the peripheral portion and the fuel gas provided on the other side of the peripheral portion for communicating with the gas passage (5) through the communication passages. A discharge channel hole (12) of the separator (4), which is communicated with the gas channel (6) through a communication channel, respectively, and an oxidizing gas supply channel hole (9) provided on the other side of the peripheral portion. And the oxidizing gas discharge flow passage hole (11) provided on the one side of the peripheral portion are respectively connected to the gas passage (5) through the communication passages and the supply of the fuel gas provided on the other side of the peripheral portion. The separator (4) in which the flow passage hole (10) and the fuel gas discharge flow passage hole (12) provided on one side of the peripheral portion are connected to the gas passageway (6) through the communication passages, respectively. A fuel cell characterized in that the cells are arranged alternately with the cells sandwiched therebetween.