JP2008226690A - Cell unit of polymer electrolyte fuel cell, and stack structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cell unit of a polymer electrolyte fuel cell capable of simply and inexpensively achieving manufacturing, of equalizing a temperature distribution, of minimizing occurrence frequency of mechanical trouble such as distortion and cracks, of preventing deterioration of unit cells, and of improving the overall fuel utilization ratio; and a stack structure. <P>SOLUTION: This cell unit of a polymer electrolyte fuel cell is provided with: cell plates 2 holding unit cells 6, and each having a gas introduction hole 21 and gas exhaust holes 22 in the center part; separator plates 3 each having a gas introduction hole 31 and gas exhaust holes 32 in the center part, and having an edge part jointed to the edge part of the cell plate 2; and straightening plates 4 making a fuel gas supplied into a space S between the both plates 2 and 3 through the gas introduction holes 21 and 31 reach the gas exhaust holes 22 and 32 in the center part via the edge parts of the plates 2 and 3. Power generation efficiency on the side of the gas introduction holes 21 and 31 is set higher than that on the side of the gas exhaust holes 22 and 32 partitioned by the straightening plates 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to a solid oxide fuel cell unit holding a single cell and a stack structure formed by laminating the unit.

  In the solid oxide fuel cell unit as described above, power is generated by flowing the fuel gas to the fuel electrode side of the single cell and the air as the oxidizing gas to the air electrode side, but the gas flow upstream of the gas concentration is high. The temperature distribution varies due to the difference in the amount of heat generated between the gas flow downstream side and the gas flow downstream side where the gas concentration decreases.

Conventionally, in order to suppress this variation in temperature distribution, the thickness of the electrolyte in the single cell is gradually reduced along the gas flow, thereby reducing the difference in heat generation between the gas flow upstream side and the gas flow downstream side. Attempts have been made to eliminate it.
JP 11-086886 A

  However, in the solid oxide fuel cell unit proposed to suppress the variation in temperature distribution to a minimum, the thickness of the electrolyte is gradually reduced along the gas flow in the same single cell. Changing the thickness of the electrolyte step by step in a single cell is extremely difficult in manufacturing, and even if it can be manufactured, there is a problem that the manufacturing cost is high, and this problem is solved. This has been a conventional problem.

  The present invention has been made paying attention to the above-described conventional problems, and can achieve a uniform temperature distribution after realizing simple and low-cost manufacturing. As a result, distortion, cracks, peeling, etc. The solid oxide fuel cell unit and the stack can reduce the frequency of occurrence of mechanical problems and can prevent deterioration of a single cell, and can improve the overall fuel utilization rate. The object is to provide a structure.

  The solid oxide fuel cell unit of the present invention includes a cell plate that holds a single cell and has a gas introduction hole and a gas discharge hole in the center part, and has a gas introduction hole and a gas discharge hole in the center part, and a peripheral part. The separator plate is bonded to the peripheral portion of the cell plate, and one of the fuel gas and air supplied through the gas introduction hole in the space formed between the cell plate and the separator plate is supplied to the peripheral portion of the two plates. The power generation efficiency of the single cell on the gas discharge hole side partitioned by the rectification plate is set higher than the power generation efficiency of the single cell on the gas introduction hole side. It is characterized by having a certain configuration, and the configuration of the solid oxide fuel cell unit is used as a means for solving the above-described conventional problems.

  In the solid oxide fuel cell unit of the present invention, the heat generation efficiency is a heat generation amount per unit area based on a product of a gas concentration and a gas flow rate in a predetermined temperature range.

  In this solid oxide fuel cell unit, one of the fuel gas and air gas is introduced into the space between the two plates forming the bag structure through the gas introduction hole, and passes through the forward path formed by the rectifying plate. To the peripheral edge of both plates, and is discharged from the gas discharge hole in the central portion via the return path similarly formed by the rectifying plate, and the other gas flows between the layers of the stacked solid oxide fuel cell units. However, compared with the power generation efficiency on the gas introduction hole side where the reaction is likely to be promoted due to the high gas concentration, the power generation efficiency on the gas exhaust hole side where the reaction is difficult to be promoted due to the low gas concentration partitioned by the rectifying plate is set high. Therefore, the difference in the amount of heat generated between the gas introduction hole side and the gas discharge hole side becomes small, and the temperature distribution is made uniform.

  At this time, it is necessary to change the power generation efficiency on the gas introduction hole side and the gas discharge hole side by changing the activity of each single cell on the gas introduction hole side and the gas discharge hole side, the thickness of the electrolyte, and the ionic conductivity. In addition, while facilitating manufacture and cost reduction, the frequency of occurrence of mechanical problems such as distortion, cracks, and peeling can be suppressed, and deterioration of the single cell can be prevented.

  According to the present invention, since it is configured as described above, it is possible to make the temperature distribution uniform while realizing simple and low-cost manufacturing, and therefore, mechanical defects such as distortion, cracks, and peeling are eliminated. Generation | occurrence | production and deterioration of a single cell can be prevented, and also the outstanding effect that improvement of the whole fuel utilization rate is realizable is brought about.

  In the solid oxide fuel cell unit of the present invention, as an embodiment thereof, as shown in FIGS. 1 and 2, a circle that holds a single cell 6 and has a gas introduction hole 21 and a gas discharge hole 22 in the central portion. The configuration includes a cell plate 2 having a shape, and a circular separator plate 3 having a gas introduction hole 31 and a gas discharge hole 32 in the central portion and having an outer peripheral edge portion insulatively bonded to the outer peripheral edge portion of the cell plate 2. The stack structure 11 according to an embodiment of the present invention can be obtained by stacking a plurality of the solid oxide fuel cell units 1 via a current collector (not shown).

  At this time, the space S formed between the plates 2 and 3 is provided with the gas introduction ports 51 and 52 communicating with the gas introduction holes 21 and 31 and the gas discharge holes 22 and 32 of the plates 2 and 3. A central flow path component 5 that supplies and discharges one gas to the inside can be disposed between the central portions of the cell plate 2 and the separator plate 3.

  The rectifying plate 4 in the solid oxide fuel cell unit of the present invention is disposed toward the outer peripheral edge of the plates 2 and 3 with the gas introduction hole 21 (31) as the center, so that the forward path A in the space S is achieved. The return path B is formed, and compared with the power generation efficiency of the forward path A on the gas introduction hole 21 (31) side where the gas concentration is high, the return path B on the gas discharge hole 22 (32) side where the gas concentration is low. By setting the power generation efficiency high, the temperature distribution can be made uniform.

  Here, in the case of having one gas introduction hole 21 (31) and four gas discharge holes 22 (32) as in the case of the solid oxide fuel cell unit 1, the central flow path component 5 It is desirable that the eight rectifying plates 4 extend radially around the center, and the four forward paths A and the four return paths B are alternately arranged. In this way, the forward paths A and the return paths B are alternately arranged. If it arrange | positions to, a much more soaking effect will be acquired.

  In the solid oxide fuel cell unit 1 of the present invention, one gas is introduced into the space S between the cell plate 2 and the separator plate 3 from the gas introduction hole 21 (31) and flows through the outer peripheral edge portion. Therefore, it is desirable that the cell plate 2 (separator plate 3) is circular and the distance from the gas introduction hole 21 (31) to the outer peripheral edge portions of both plates is equal, but the cell plate 2 (separator plate 3) is polygonal. For example, as shown in FIG. 6, the cell plate 2 (separator plate 3) may have an octagonal shape.

  In the solid oxide fuel cell unit 1 shown in FIGS. 1 and 6, the cell plate 2 (separator plate 3) has one gas introduction hole 21 (31) and four gas discharge holes 22 (32). However, the number of the gas introduction holes 21 (31) and the number of the gas discharge holes 22 (32) are not limited to this. For example, as shown in FIG. Two gas discharge holes 22 (32) can be formed with respect to the hole 21 (31). In this case, the two rectifying plates 4 are in opposite directions around the gas introduction hole 21 (31). It is desirable to arrange for

  In the solid oxide fuel cell unit of the present invention, the power generation efficiency on the gas discharge hole side partitioned by the rectifying plate is set higher than the power generation efficiency on the gas introduction hole side. The structure which arrange | positions the single cell of higher electric power generation efficiency than a cell to the gas exhaust hole side is employable.

  Specifically, as shown in FIG. 5, the activity of the single cell 6 is increased from the forward path A on the gas introduction hole 21 (31) side to the return path B on the gas discharge hole 22 (32) side (different on the same substrate). Activity, for example, an electrode is formed along the gas flow direction), and as shown in FIG. 8, the active path A is active on the outward path A on the gas introduction hole 21 (31) side and the return path B on the gas discharge hole 22 (32) side. It is possible to employ a configuration in which different single cells 6 are arranged along the gas flow direction.

  In this way, by forming the film by changing the activity of the single cell 6 along the gas flow direction, the frequency of occurrence of mechanical troubles such as distortion, cracks, and peeling is reduced while facilitating manufacturing and reducing costs. In addition to reducing the number of single cells 6, the single cell 6 can be prevented from being deteriorated. In addition, a plurality of single cells 6 having different functions are dispersed in the solid oxide fuel cell unit 1 to mount a large single cell. Compared to the case, the occurrence of warpage and distortion in the manufacturing stage can be suppressed to a small extent, and cracks and separation between materials caused during operation and stoppage due to the difference in thermal expansion coefficient between different materials can be suppressed.

  Furthermore, in the solid oxide fuel cell unit of the present invention, the power generation efficiency on the gas discharge hole side partitioned by the rectifying plate is set higher than the power generation efficiency on the gas introduction hole side. Adopting a configuration in which a single cell of electrolyte thinner than the cell is arranged on the gas discharge hole side, specifically, a configuration in which each electrolyte of a plurality of single cells arranged along the gas flow direction becomes gradually thinner. Can do.

  In this way, a single cell with a thick electrolyte is arranged on the gas introduction hole side where the reaction is likely to be promoted because the gas concentration is high, and the cell resistance is intentionally increased to reduce the reaction amount, while the gas concentration is low. Because a single cell with a thin electrolyte is placed on the gas discharge hole side where the reaction is difficult to promote in order to lower the cell resistance and increase the reaction amount, the temperature distribution can be made uniform, resulting in easy manufacturing. In addition, the frequency of occurrence of mechanical problems such as distortion, cracks, and peeling can be suppressed and deterioration of the single cell can be prevented.

  Furthermore, in the solid oxide fuel cell unit of the present invention, the power generation efficiency on the gas discharge hole side partitioned by the rectifying plate is set higher on the gas introduction hole side than the power generation efficiency on the gas introduction hole side. A configuration in which a single cell having an electrolyte having higher ion conductivity than that of the single cell is arranged on the gas discharge hole side, specifically, each ion conductivity of a plurality of single cells arranged along the gas flow direction is gradually increased. The structure which makes it can be employ | adopted.

  In this way, a single cell having an electrolyte with low ionic conductivity is arranged on the gas introduction hole side where the reaction is likely to be promoted because the gas concentration is high, so that the reaction amount is intentionally reduced, while the gas concentration is low. The reaction volume is increased by placing a single cell with an electrolyte with high ionic conductivity on the side of the gas discharge hole where the reaction is difficult to promote, so that the temperature distribution can be made uniform, resulting in easy manufacturing. In addition, the frequency of occurrence of mechanical problems such as distortion, cracks, and peeling can be suppressed and deterioration of the single cell can be prevented.

  Furthermore, in the solid oxide fuel cell unit of the present invention, the power generation efficiency on the gas discharge hole side partitioned by the rectifying plate is set higher on the gas introduction hole side than the power generation efficiency on the gas introduction hole side. A configuration in which a single cell having a larger power generation area ratio than the single cell is disposed on the gas discharge hole side can be employed. Here, the power generation area ratio is a ratio of the area of the power generation element based on the area of the solid oxide fuel cell unit and the single cell substrate.

  Specifically, each power generation area ratio of the plurality of single cells arranged along the gas flow direction is gradually increased, that is, as shown in FIG. 3, the rectifying plate of the solid oxide fuel cell unit 1 A configuration in which the electrode area of the return path B partitioned by 4 is larger than the electrode area of the forward path A can be employed.

  In this way, the gas introduction hole side on which the reaction is likely to be promoted because the gas concentration is high reduces the power generation area ratio to intentionally reduce the reaction amount, while the gas concentration is low and the reaction is difficult to promote. Since the power generation area ratio is increased on the discharge hole side to increase the reaction amount, the temperature distribution can be made uniform. As a result, the manufacturing process is simplified and the cost is reduced. As a result, the frequency of occurrence of mechanical problems such as peeling and peeling can be reduced, and deterioration of the single cell can also be prevented.

  Furthermore, in the solid oxide fuel cell unit of the present invention, the power generation efficiency on the gas discharge hole side partitioned by the rectifying plate is set higher on the gas introduction hole side than the power generation efficiency on the gas introduction hole side. A configuration in which a single cell having an electrode having a higher conductivity than that of the single cell is arranged on the gas discharge hole side, specifically, the conductivity of each of the plurality of single cells arranged along the gas flow direction is gradually increased. It is possible to adopt a configuration to

  In this way, a single cell having an electrode with low conductivity is arranged on the gas introduction hole side where the reaction is likely to be promoted because the gas concentration is high, so that the reaction amount is intentionally reduced, while the gas concentration is low. Since a single cell having an electrode with high conductivity is arranged on the gas discharge hole side where the reaction is difficult to promote, the reaction amount is increased, so that the temperature distribution can be made uniform. In addition to cost reduction, the frequency of occurrence of mechanical problems such as distortion, cracks, and peeling can be suppressed, and deterioration of the single cell can be prevented.

  In general, if the porosity of the single cell electrode is lowered, the electrical conductivity can be increased, but it is difficult to supply gas to the electrode and it is easy to cause concentration overvoltage. On the other hand, if the porosity of the single cell electrode is lowered. Although the electrical conductivity is lowered, gas is easily supplied to the electrode, and it is difficult to cause concentration overvoltage.

  Therefore, in the solid oxide fuel cell unit of the present invention, the power generation efficiency on the gas discharge hole side partitioned by the rectifying plate is set higher than the power generation efficiency on the gas introduction hole side. A structure in which a single cell having an electrode having a higher porosity than that of the cell is arranged on the gas discharge hole side, for example, a pore-extinguishing agent put into each fuel electrode (NiO-YSZ) of a plurality of single cells arranged along the gas flow direction The porosity is gradually increased by using a fuel electrode substrate cell fired at 1400 ° C. on the upstream side of the gas flow and using a fuel electrode substrate cell fired at 1350 ° C. on the downstream side of the gas flow. It is desirable that the configuration be such that

  In the case of adopting this configuration, in the vicinity of the gas introduction hole, since the gas concentration is high, the concentration overvoltage hardly occurs and the gas consumption can be suppressed to a low level, and the overvoltage is reduced by the ohmic resistance. In the vicinity, although the gas concentration decreases, the porosity of the single-cell electrode is large, so that concentration overvoltage is unlikely to occur. Therefore, the performance during operation with a high reaction gas utilization rate can be further improved.

  Furthermore, the solid oxide fuel cell unit of the present invention comprises a current collector disposed in a space formed between the cell plate and the separator plate, and a single cell electrode and collector disposed on the gas introduction hole side. By lowering the resistance value of the electrode of the single cell and the current collector arranged on the gas discharge hole side than the resistance value of the electric body, the power generation efficiency on the gas introduction hole side is closer to the gas discharge hole side partitioned by the rectifying plate. A configuration in which the power generation efficiency is set high can be employed.

  Specifically, the resistance values of the electrodes and current collectors of the plurality of single cells arranged along the gas flow direction (the sum of the surface contact resistance value and the current collector resistance value) are gradually lowered. A configuration can be employed. For example, Pt is used for the current collector that contacts the electrode of the single cell located on the upstream side of the gas, and Ni is used for the current collector that contacts the electrode of the single cell located on the downstream side. The contact area between the electrode of the single cell located on the side and the current collector is 1-2%, and the contact area between the electrode of the single cell located on the downstream side and the current collector is 5-10%.

  In this way, the current collector function is divided to increase the resistance of the single cell electrode and the current collector on the gas introduction hole side where the reaction is likely to be promoted due to the high gas concentration, thereby reducing the reaction amount. On the other hand, since the reaction amount is increased by lowering the resistance value of the electrode and current collector of the single cell on the gas discharge hole side where the reaction is difficult to be promoted due to the low gas concentration, a single plate-shaped single cell is formed. The temperature distribution can be made uniform without dividing the function for each reaction field. As a result, the frequency of occurrence of mechanical problems such as distortion, cracks and delamination can be reduced while facilitating manufacturing and reducing costs. It can be suppressed to a small extent, and deterioration of the single cell can be prevented.

  On the other hand, in a stack structure formed by stacking solid oxide fuel cell units, the gas introduction hole portion where the reaction is likely to be promoted due to the high gas concentration has a large reaction amount, a large calorific value, and a low gas concentration. The reaction amount is small and the calorific value is small in the gas discharge hole portion where the reaction is difficult to be accelerated.

  Therefore, in the stack structure of the present invention in which a plurality of the solid oxide fuel cell units are stacked, as shown in FIG. 4, gas introduction with high power generation efficiency in one adjacent solid oxide fuel cell unit 1 is performed. It is desirable to adopt a configuration in which a hole portion (outward path) A and a gas discharge hole portion (return path) B having low power generation efficiency in the other solid oxide fuel cell unit 1 are overlapped with each other.

  By adopting this configuration, the temperature distribution in the stacking direction of the solid oxide fuel cell unit can be made uniform, and the overall frequency of occurrence of mechanical problems can be reduced. The fear of an electrical connection failure between the electrolyte fuel cell units is eliminated, and a gas flow path between the cell units is secured.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example.

[Example 1]
1 and 2 show an embodiment of the present invention. As shown in FIGS. 1 and 2, in this embodiment, the fuel electrode of the single cell 6 of the solid oxide fuel cell unit 1 is made of nickel. + Yttria stabilized zirconia cermet, 10 mol percent yttria stabilized zirconia electrolyte, air electrode lanthanum strontium manganite, fuel electrode, electrolyte and air electrode formed by sputtering, and fuel electrode support A single cell 6 of the type was obtained.

  The circular cell plate 2 holding the single cell 6 is made of a SUS material, and the support portion of the single cell 6 and the cell plate 2 are joined by brazing. The separator plate 3 was also made of SUS material.

  The cell plate 2 (separator plate 3) is provided with one gas introduction hole 21 (31) and four gas discharge holes 22 (32), and eight sheets centering on the gas introduction hole 21 (31). The rectifying plates 4 were extended radially, and four forward paths A and four return paths B were alternately arranged.

  In this case, in the single cell 6 arranged in the forward path A, that is, in the single cell 6 arranged on the gas introduction hole 21 (31) side where the reaction is easily promoted due to the high gas concentration, an ion having a thickness of 20 μm is formed in the electrolyte. Using 3YSZ with low conductivity and the volume ratio of NiO-YSZ as the fuel electrode to 30 vol%, on the other hand, in the single cell 6 arranged in the return path B, that is, gas discharge that is difficult to promote reaction due to low gas concentration In the single cell 6 arranged on the hole 22 (32) side, 8YSZ having a high ion conductivity of 10 μm in thickness was used for the electrolyte layer, and the volume ratio of NiO—YSZ as the fuel electrode was set to 40 vol%.

  Then, a plurality of solid oxide fuel cell units 1 formed by joining the outer peripheral edge portions of the cell plate 2 and the separator plate 3 were stacked to obtain a stack structure 11.

  As described above, in the solid oxide fuel cell unit 1, the gas discharge hole 22 (32) in which the gas concentration decreases while the reaction amount in the vicinity of the gas introduction hole 21 (31) in which the gas concentration is high is reduced. Since the reaction amount in the vicinity is increased, the uniformity of the temperature distribution is improved.

[Example 2]
FIG. 3 shows another embodiment of the present invention. As shown in FIG. 3, the fuel electrode, electrolyte, and air electrode of the single cell 6 of the solid oxide fuel cell unit 1 are used in this embodiment. The same material as that of the single cell 6 of Example 1 is used. After the fuel electrode is screen-printed on the porous metal body (SUS430) as the cell support portion, the electrolyte and the air electrode are formed by sputtering. A single cell 6 of this example was obtained.

  Also in this embodiment, a SUS-based material is used for the circular cell plate 2 holding the single cell 6, and the porous metal body as the cell support portion of the single cell 6 and the cell plate 2 are joined by brazing. did. The separator plate 3 was also made of SUS material.

  In this embodiment, the fan A-shaped forward path A formed by the eight rectifying plates 4 has an expansion angle of about 30 °, and in the single cell 6 arranged in the forward path A, the air electrode Lal-xSrxMnO3 is set to x = 0. Sputter film formation was performed, and the fan B-shaped return path B was spread at an angle of about 60 °. In the single cell 6 arranged in the return path B, the air electrode Lal-xSrxMnO3 was sputtered at x = 0.5.

  As described above, in the solid oxide fuel cell unit 1, the area ratio of the electrodes of the forward path A and the backward path B is 1: 2, so the outbound path close to the gas introduction hole 21 (31) where the concentration of the reaction gas is high. The reaction gas consumption at A is reduced, and conversely, the reaction in the return path B close to the gas discharge hole 22 (32) where the concentration of the reaction gas is low is promoted, so that the solid electrolyte The uniformity of the temperature distribution of the entire fuel cell unit 1 is improved.

[Example 3]
In this embodiment, the constituent material of the single cell 6 and the constituent material of the cell plate 2 (separator plate 3) are the same as those of the solid oxide fuel cell unit 1 of the first embodiment. Bonding was performed in the same manner as in Example 1. Then, four forward paths A and four return paths B were formed by the eight rectifying plates 4.

  In the solid oxide fuel cell unit 1 in this embodiment, in the single cell 6 arranged in the forward path A, that is, the single cell arranged on the gas introduction hole 21 (31) side where the reaction is easily promoted due to the high gas concentration. 6, the amount of the pore-increasing agent to be put into the fuel electrode is 5% of the total, while in the single cell 6 arranged in the return path B, that is, the gas discharge holes 22 ( In the single cell 6 arranged on the 32) side, the amount of the pore-increasing agent put into the fuel electrode was 20% of the whole.

  As described above, in the solid oxide fuel cell unit 1, the porosity of the fuel electrode gradually increases from the vicinity of the gas introduction hole 21 (31) to the vicinity of the gas discharge hole 22 (32). Therefore, in the vicinity of the gas introduction hole, the gas concentration is high, so that the concentration overvoltage hardly occurs and the consumption of gas can be reduced, and the overvoltage is reduced by the ohmic resistance. On the other hand, the gas concentration is near the gas discharge hole. Although it decreases, concentration overvoltage is less likely to occur as much as the porosity of the single cell electrode increases, and as a result, the performance during operation with a high reaction gas utilization rate is further improved.

[Example 4]
In this embodiment, the constituent material of the single cell 6 and the constituent material of the cell plate 2 (separator plate 3) are the same as those of the solid oxide fuel cell unit 1 of the first embodiment. Bonding was performed in the same manner as in Example 1.

  In the solid oxide fuel cell unit 1 in this embodiment, the single cell 6 arranged on the gas introduction hole 21 (31) side where the reaction is easily promoted due to the high gas concentration, that is, the single cell located on the gas upstream side. The contact area between the electrode 6 and the current collector is 1 to 2%, and the gas concentration is low, and the reaction is difficult to be promoted by the single cell 6 arranged on the gas discharge hole 22 (32) side, that is, on the gas downstream side. The contact area between the electrode of the single cell 6 positioned and the current collector was 5 to 10%.

  As described above, in the solid oxide fuel cell unit 1, the gas discharge hole 22 (32) in which the gas concentration decreases while the reaction amount in the vicinity of the gas introduction hole 21 (31) in which the gas concentration is high is reduced. Since the reaction amount in the vicinity is increased, the uniformity of the temperature distribution is improved. In addition, since the same specification can be used for a plurality of single cells, management and manufacture are easy.

[Example 5]
FIG. 4 shows another embodiment of the stack structure of the present invention in which a plurality of solid oxide fuel cell units 1 of Embodiment 1 are stacked. As shown in FIG. 4, in the stack structure 11 in this embodiment, a gas introduction hole portion (outward path) A with high power generation efficiency in one adjacent solid oxide fuel cell unit 1 and the other solid electrolyte fuel A gas discharge hole portion (return path) B having low power generation efficiency in the battery cell unit 1 is overlapped with each other.

  As described above, in the stack structure 11, the slight variation in temperature distribution generated in the solid oxide fuel cell unit 1 is alleviated by heat exchange in the vertical direction. Since the temperature distribution in the stacking direction of the units 1 is made uniform, the occurrence frequency of overall mechanical problems can be reduced, and as a result, between the solid oxide fuel cell units 1 and 1 The concern about the occurrence of poor electrical connection is eliminated, and the gas flow path between the cell units 1 and 1 is secured.

FIG. 3 is an explanatory plan view showing a solid oxide fuel cell unit according to an embodiment of the present invention with a separator plate omitted. (Example 1) FIG. 2 is a simplified cross-sectional explanatory view of a stack structure formed by stacking a plurality of solid oxide fuel cell units of FIG. 1. (Example 1) FIG. 6 is an explanatory plan view showing a solid oxide fuel cell unit according to another embodiment of the present invention with a separator plate omitted. (Example 2) FIG. 5 is a simplified cross-sectional explanatory view showing another embodiment of a stack structure formed by stacking a plurality of solid oxide fuel cell units of FIG. 1. (Example 5) It is a plane explanatory view showing a solid oxide fuel cell unit according to another configuration example of the present invention, omitting a separator plate. It is a plane explanatory view which omits a separator plate and shows a solid oxide fuel cell unit according to still another configuration example of the present invention. It is a plane explanatory view which omits a separator plate and shows a solid oxide fuel cell unit according to still another configuration example of the present invention. It is plane explanatory drawing (a)-(c) which abbreviate | omits a separator plate and shows the solid oxide fuel cell unit by the further another structural example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid oxide fuel cell unit 2 Cell plate 3 Separator plate 4 Rectification plate 6 Single cell 21, 31 Gas introduction hole 22, 32 Gas discharge hole 11 Stack structure S Space

Claims (9)

A cell plate having a plurality of single cells and having a gas introduction hole and a gas discharge hole in the central portion, and a separator having a gas introduction hole and a gas discharge hole in the central portion and having a peripheral portion joined to the peripheral portion of the cell plate One gas out of the fuel gas and air supplied through the gas introduction hole into the space formed between the plate and the cell plate and the separator plate passes through the peripheral portion of both plates to the gas discharge hole in the central portion. A solid oxide fuel cell comprising a rectifying plate to be reached, wherein power generation efficiency by a single cell on the gas discharge hole side partitioned by the rectification plate is set higher than power generation efficiency by a single cell on the gas introduction hole side Cell unit. By placing a single cell with higher power generation efficiency on the gas discharge hole side than the single cell placed on the gas introduction hole side, the power generation efficiency on the gas discharge hole side partitioned by the rectifying plate is higher than the power generation efficiency on the gas introduction hole side. The solid oxide fuel cell unit according to claim 1, which is set high. By disposing a single cell of electrolyte thinner than the single cell disposed on the gas introduction hole side on the gas discharge hole side, the power generation efficiency on the gas discharge hole side partitioned by the rectifying plate is higher than the power generation efficiency on the gas introduction hole side. The solid oxide fuel cell unit according to claim 1, which is set. The gas discharge hole side partitioned by a rectifying plate rather than the power generation efficiency on the gas introduction hole side by disposing a single cell having an electrolyte having higher ion conductivity on the gas discharge hole side than the single cell arranged on the gas introduction hole side The solid oxide fuel cell unit according to claim 1, wherein the power generation efficiency is set high. By arranging a single cell with a larger power generation area ratio on the gas discharge hole side than the single cell arranged on the gas introduction hole side, the power generation efficiency on the gas discharge hole side partitioned by the rectifying plate rather than the power generation efficiency on the gas introduction hole side The solid oxide fuel cell unit according to claim 1, wherein is set high. By disposing a single cell having an electrode with higher conductivity than the single cell disposed on the gas introduction hole side on the gas discharge hole side, the gas discharge hole side partitioned by the rectifying plate is separated from the power generation efficiency on the gas introduction hole side. 2. The solid oxide fuel cell unit according to claim 1, wherein power generation efficiency is set high. By disposing a single cell having an electrode having a higher porosity than that of the single cell disposed on the gas introduction hole side on the gas discharge hole side, the gas discharge hole side partitioned by the rectifying plate is separated from the power generation efficiency on the gas introduction hole side. 2. The solid oxide fuel cell unit according to claim 1, wherein power generation efficiency is set high. A current collector disposed in a space formed between the cell plate and the separator plate, and a single cell disposed on the gas discharge hole side than the resistance value of the electrode and current collector disposed on the gas introduction hole side; 2. The solid according to claim 1, wherein the power generation efficiency on the gas discharge hole side partitioned by the rectifying plate is set higher than the power generation efficiency on the gas introduction hole side by lowering the resistance value of the electrode of the cell and the current collector. Electrolytic fuel cell unit. A gas introduction hole portion having a high power generation efficiency in one of the adjacent solid electrolyte fuel cell units, the other solid electrolyte fuel cell unit being formed by laminating a plurality of the solid oxide fuel cell units according to any one of claims 1 to 8 A stack structure characterized in that gas discharge hole portions having low power generation efficiency in a fuel cell unit are overlapped with each other.

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