fuel cell system

Abstract

To provide a fuel cell system capable of suppressing anode gas supply shortage after aging.SOLUTION: A fuel cell system includes a cell stack 2 in which a plurality of battery cells 20 is stacked, an anode gas supply channel that supplies anode gas to an anode chamber 22 of the cell stack 2, and a cathode gas supply channel that supplies cathode gas to a cathode chamber 24 of the cell stack 2. A stack main body 30 is provided with an anode gas distribution channel 44 extending in the stacking direction, and the anode gas from the anode gas supply channel is distributed to a portion corresponding to the center side portion (center stage portion) of the plurality of battery cells 20 in the anode gas distribution channel 44, and is fed to the anode chamber 22 of the corresponding battery cell 20 after being distributed so as to flow through the anode gas distribution channel 44 to both ends in the axial direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a fuel cell system including a cell stack in which battery cells are stacked. [Background technology]

[0002] A known fuel cell system includes a cell stack in which flat battery cells are stacked, an anode gas supply passage that supplies anode gas (fuel gas) to the anode chamber of the cell stack, a cathode gas supply passage that supplies cathode gas (oxidant gas) to the cathode gas chamber of the cell stack, an anode gas supply means for supplying the anode gas, and a cathode gas supply means for supplying the cathode gas. In such a fuel cell system, the fuel utilization rate in the cell stack must be maintained within a certain range. If the system continues to operate with an excessively high fuel utilization rate (i.e., a state of anode gas shortage), the battery cells will be damaged, making it difficult to continue power generation operation.

[0003] In a cell stack made up of multiple flat battery cells stacked on top of each other, there is a temperature distribution in the stacking direction (i.e., thickness direction), and heat tends to build up in the central area in the stacking direction (the so-called central section), with the temperature of this central area tending to be higher than that of the areas on both ends (the so-called end sections).

[0004] Generally, fuel cell systems deteriorate over time, increasing the resistance of the cell stack, and the amount of heat generated tends to increase in areas where this resistance is high. In particular, the center of the cell stack, where temperatures are higher, deteriorates more quickly than the areas on either end, resulting in even higher temperatures.

[0005] In this cell stack, which is made up of stacked flat battery cells, the anode gas supplied through the anode gas supply flow path is set to be evenly distributed to the multiple battery cells in the initial state (when first installed). However, since the viscosity of anode gas increases as the temperature increases, resulting in greater pressure loss, if the temperature distribution changes due to deterioration of the cell stack over time, this temperature distribution will also cause a change in the pressure loss at the inlet of the anode chamber of each battery cell, and this fluctuation in pressure loss will change the amount of anode gas distributed to each battery cell.

[0006] For example, in the high temperature part of the cell stack (the central part), the pressure loss at the inlet of the anode chamber increases, which reduces the flow rate of anode gas distributed to this anode chamber, causing an insufficient supply of anode gas (so-called fuel starvation).If this insufficient supply of anode gas continues, the battery cells will be damaged.

[0007] For this reason, fuel cell systems have been proposed that solve the problem of insufficient anode gas supply in the cell stack. For example, systems have been proposed that measure the resistance value of each battery cell to determine the fuel utilization rate in each battery cell and prevent insufficient anode gas supply based on the determined fuel utilization rate (see, for example, Patent Document 1), systems that use data on the output current of the cell stack versus the fuel utilization rate to adjust the anode gas supply flow rate so that the fuel utilization rate is below a predetermined value (see, for example, Patent Document 2), and systems that detect insufficient anode gas supply (fuel starvation) using the cell stack voltage change rate and resistance change rate as indicators and adjust the anode gas supply flow rate or the power generation output of the cell stack to prevent damage to the cell stack (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-110666 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-59550 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-103198 Summary of the Invention [Problem to be solved by the invention]

[0009] However, these conventional fuel cell systems have the following problems: For example, in the fuel cell system of Patent Document 1, when a shortage of anode gas supply is detected, the flow rate of anode gas supplied to all of the battery cells in the cell stack is increased, but this type of anode gas supply control increases the flow rate of anode gas supplied even to battery cells that are not experiencing a shortage of anode gas supply, resulting in a problem of reduced power generation efficiency.

[0010] Furthermore, in the fuel cell system of Patent Document 2, the fuel utilization rate of the entire cell stack can be grasped, but the fuel utilization rate of some of the battery cells in the cell stack cannot be grasped, and therefore the partial anode gas supply shortage in the cell stack cannot be resolved.

[0011] Furthermore, in the fuel cell system of Patent Document 3, when a shortage of anode gas supply in the cell stack is detected, the supply flow rate of anode gas is increased for all of the battery cells in the cell stack. However, as described above, this type of anode gas supply control increases the supply flow rate of anode gas even for battery cells that are not experiencing a shortage of anode gas supply, resulting in a decrease in power generation efficiency.

[0012] An object of the present invention is to provide a fuel cell system that can prevent a shortage of anode gas supply after aging. [Means for solving the problem]

[0013] A fuel cell system according to claim 1 of the present invention is a fuel cell system comprising: a cell stack in which a plurality of battery cells are stacked, each battery cell having an ion-conducting electrolyte layer, an anode disposed on one side of the electrolyte layer, and a cathode disposed on the other side of the electrolyte layer; an anode gas supply flow path for supplying anode gas to an anode chamber of the cell stack; a cathode gas supply flow path for supplying cathode gas to a cathode chamber of the cell stack; an anode gas supply means for supplying the anode gas; and a cathode gas supply means for supplying the cathode gas, The cell stack includes a stack body for supporting the plurality of battery cells, are provided with an anode gas inlet flow path into which the anode gas flows from the anode gas supply flow path and an anode gas distribution flow path that distributes the anode gas, and are also provided with a cathode gas inlet flow path into which the cathode gas flows from the cathode gas supply flow path and a cathode gas distribution flow path that distributes the cathode gas, The anode gas inlet flow path and the anode gas distribution flow path In the stacking direction of the plurality of battery cells Extend, anode gas distribution flow path is provided with anode gas introduction flow paths that communicate with the anode chambers of the plurality of battery cells and are spaced apart in the stacking direction; the cathode gas inlet flow path and the cathode gas distribution flow path extend in a stacking direction of the plurality of battery cells, and the cathode gas distribution flow path is provided with cathode gas introduction flow paths that communicate with the cathode chambers of the plurality of battery cells and are spaced apart in the stacking direction; Furthermore, the cathode gas distribution flow path extends parallel to the anode gas distribution flow path in the stacking direction of the plurality of battery cells, and the cathode gas inlet flow path and the anode gas inlet flow path of the plurality of battery cells are arranged close to each other, the anode gas inlet channel The anode gas from the anode gas distribution flow channel is supplied to the anode gas distribution flow channel from a portion corresponding to a central portion in the stacking direction of the plurality of battery cells, flows through the anode gas distribution flow channel to be distributed to both ends, and then flows into the anode chambers of the plurality of battery cells through the corresponding anode gas introduction flow channel. The cathode gas from the cathode gas inlet flow path is supplied to the cathode gas distribution flow path from a portion of the cathode gas distribution flow path that corresponds to a central portion of the plurality of battery cells in the stacking direction, flows through the cathode gas distribution flow path to both ends, and is distributed, and then supplied to the cathode chambers of the plurality of battery cells through the corresponding cathode gas introduction flow path. It is characterized by:

[0014] In addition, in the fuel cell system according to claim 2 of the present invention, The anode gas inlet channel is in the lamination direction in parallel with the anode gas distribution flow path Extend, The anode gas inlet flow path and the anode gas distribution flow path are connected via an anode gas connection flow path, and the anode gas connection flow path is provided in a portion of the stack body corresponding to the central portion of the plurality of battery cells, and the anode gas from the anode gas supply flow path is supplied to the anode gas distribution flow path through the anode gas inlet flow path and the anode gas connection flow path.

[0016] Furthermore, the claims of the present invention 3 In the fuel cell system described in The cathode gas inlet channel is In the stacking direction, parallel to the cathode gas distribution flow path Extend, The cathode gas inlet flow path and the cathode gas distribution flow path are connected via a cathode gas connection flow path, and the cathode gas connection flow path is provided in a portion of the stack body corresponding to the central portion of the plurality of battery cells, and the cathode gas from the cathode gas supply flow path is supplied to the cathode gas distribution flow path through the cathode gas inlet flow path and the cathode gas connection flow path. [Effects of the Invention]

[0017] According to the fuel cell system of claim 1 of the present invention, the stack body for supporting the multiple battery cells is provided with an anode gas distribution flow path that communicates with each of the anode chambers of the multiple battery cells. The anode gas from the anode gas supply flow path is supplied to the anode gas distribution flow path from a portion corresponding to the central portion in the stacking direction of the multiple battery cells, flows through this anode gas distribution flow path to both end portions, is distributed, and then is supplied to the anode chambers of the multiple battery cells. As a result, anode gas at a low temperature is supplied to the portion corresponding to the central portion in the stacking direction of the multiple battery cells, and the anode gas that flows into the anode gas distribution flow path is heated as it flows to both end portions. By regulating the flow of anode gas in the cell stack in this way, the temperature of the anode gas introduction flow path in the central portion and both end portions of the cell stack is made uniform, and as a result, a shortage of anode gas supply (starvation of fuel) can be avoided. In addition, a cathode distribution flow path is provided in the stack body, and this cathode distribution flow path is provided with a cathode gas inlet flow path that communicates with the cathode chambers of the multiple battery cells. Cathode gas from the cathode gas supply flow path is supplied to the cathode gas distribution flow path from a portion corresponding to the central portion in the stacking direction of the multiple battery cells, flows through this cathode gas distribution flow path to both end sides and is distributed before being supplied to the cathode chambers of the multiple battery cells.As a result, cathode gas at a low temperature is supplied to the portion corresponding to the central portion in the stacking direction of the multiple battery cells, and the cathode gas that flows into the cathode gas distribution flow path is heated as it flows to both end sides.By regulating the flow of cathode gas in the cell stack in this way, it is possible to equalize the temperature of the cathode gas inlet flow path in the central portion and both end sides of the cell stack. Furthermore, the cathode gas distribution flow path extends parallel to the anode gas distribution flow path, and this cathode distribution flow path is provided with a cathode gas inlet flow path that communicates with the cathode chambers of the multiple battery cells. The cathode gas from the cathode gas supply flow path is delivered to the cathode gas distribution flow path from a portion corresponding to the central portion in the stacking direction of the multiple battery cells, flows inside this cathode gas distribution flow path to both end portions, is distributed, and then delivered to the cathode chambers of the multiple battery cells. Therefore, cathode gas at a low temperature is delivered to the portion corresponding to the central portion in the stacking direction of the multiple battery cells, and the cathode gas that flows into the cathode gas distribution flow path is heated as it flows to both end portions. By regulating the flow of cathode gas in the cell stack in this way, it is possible to equalize the temperature of the cathode gas inlet flow path in the central portion and both end portions of the cell stack. Furthermore, since the cathode inlet flow paths and anode gas inlet flow paths of multiple battery cells are arranged close to each other, the uniformity of the cathode gas temperature contributes to the anode gas inlet flow path, thereby enabling the temperature of the anode gas inlet flow path to be more uniform.

[0018] Furthermore, according to a fuel cell system according to a second aspect of the present invention, Anode gas inlet passage Parallel to the anode gas distribution channel Extend,The anode gas inlet flow path and the anode gas distribution flow path are connected via the anode gas connecting flow path at a location corresponding to the central portion of the plurality of battery cells. Therefore, the anode gas supplied through the anode gas inlet flow path is sent to the anode distribution flow path through the anode connecting flow path, and the anode gas that flows into the anode gas distribution flow path is heated as it flows to both end sides. By flowing the anode gas in this manner, the temperature of the anode gas introduction flow path in the central portion and both end side portions of the cell stack can be made uniform.

[0020] Furthermore, according to the fuel cell system of the present invention, The cathode gas inlet channel is In parallel with the cathode gas distribution channel Extend, This cathode gas inlet flow path and cathode gas distribution flow path are connected via the cathode gas connecting flow path at a location corresponding to the central portion of the multiple battery cells, so that the cathode gas supplied through the cathode gas inlet flow path is sent to the cathode gas distribution flow path through the cathode connecting flow path, and the cathode gas that flows into this cathode gas distribution flow path is heated as it flows to both end sides. By flowing the cathode gas in this manner, the temperature of the cathode gas introduction flow paths at the central portion and both end sides of the cell stack is made uniform, and this also contributes to the anode gas introduction flow path, making it possible to further uniform the temperature of the anode gas introduction flow path. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a simplified overall view showing a first embodiment of a fuel cell system according to the present invention; [Figure 2] FIG. 2 is a simplified perspective view showing a cell stack of the fuel cell system of FIG. 1. [Figure 3] FIG. 3 is a plan view showing a simplified view of the cell stack of FIG. 2. [Figure 4] FIG. 3 is a cross-sectional view showing a simplified view of the cell stack of FIG. 2. [Figure 5] FIG. 4 is a plan view showing a simplified view of a cell stack in a second embodiment of a fuel cell system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] Various embodiments of a fuel cell system according to the present invention will now be described with reference to the accompanying drawings. First, a first embodiment of a fuel cell system according to the present invention will be described with reference to Figs.

[0023] 1, the fuel cell system of the first embodiment includes a cell stack 2 that generates power through an electrochemical reaction between an anode gas (e.g., hydrogen as a fuel gas) and a cathode gas (e.g., air as an oxidant gas), and an anode gas supply flow path 4 that supplies the anode gas (fuel gas) and a cathode gas supply flow path 6 that supplies the cathode gas (oxidant gas) are provided on the inlet side of the cell stack 2. Also, an anode off-gas discharge flow path 8 that discharges the anode off-gas and a cathode off-gas discharge flow path 10 that discharges the cathode off-gas are provided on the outlet side of the cell stack 2.

[0024] The anode gas supply flow path 4 is provided with anode gas supply means 12 for supplying anode gas, and this anode gas supply means 12 is composed of, for example, a fuel pump, a fuel blower, etc. The upstream side of this anode gas supply flow path 4 is connected to, for example, an anode gas cylinder 18 as an anode gas supply source, and the anode gas from the anode gas cylinder 18 is supplied through the anode gas supply flow path 4. Furthermore, the cathode gas supply flow path 6 is provided with, for example, an air blower 16 as cathode gas supply means, and the cathode gas is supplied through the cathode gas supply flow path 4.

[0025] 2 and 4, the cell stack 2 includes a plurality of battery cells 20 stacked vertically in FIGS. 2 and 4, with each battery cell 20 consisting of a flat cell of substantially the same shape. Although not specifically shown, each battery cell 20 includes, for example, an ion-conducting solid oxide electrolyte layer, an anode (fuel electrode) disposed on one side of the electrolyte layer (the lower side in FIG. 4), and a cathode (air electrode) disposed on the other side of the electrolyte layer (the upper side in FIG. 4). Interconnectors 26 are disposed between each battery cell 20, and an anode chamber 22 is defined on the anode side of each battery cell 20, and a cathode chamber 24 is defined on the cathode side thereof. The plurality of battery cells 20 are electrically connected via the interconnectors 26, and the generated power of these battery cells 20 is collected by current collector plates 28 disposed at both ends of the cell stack 2 and extracted.

[0026] In this embodiment, the cell stack 2 includes a stack body 30 for supporting the plurality of battery cells 20. The stack body 30 is provided with an anode gas inlet flow path 32 that communicates with the anode gas supply flow path 4, and an anode off-gas outlet flow path 34 that communicates with the anode off-gas discharge flow path 8. In this embodiment, the anode gas inlet flow path 32 is formed by an anode gas inlet manifold 36 that extends in the stacking direction of the plurality of battery cells 20. The anode off-gas outlet flow path 34 is formed by an anode off-gas outlet manifold 38 that extends in the stacking direction of the plurality of battery cells 20. The anode off-gas outlet manifold 38 is provided with anode gas outlet flow paths 40 (see FIG. 4 ) that correspond to each of the anode chambers 22 of the plurality of battery cells 20 in the cell stack 2 and are spaced apart in the stacking direction.

[0027] In this embodiment, an anode gas distribution manifold 42 is provided that extends parallel to the anode gas inlet manifold 36, and this anode gas distribution manifold 42 defines anode gas distribution channels 44 that distribute the anode gas to the anode chambers 22 of each battery cell 20. This anode gas distribution manifold 42 extends in the stacking direction of the multiple battery cells 20, and is provided with anode gas introduction channels 46 that correspond to the anode chambers 22 of each battery cell 20 and are spaced apart in the stacking direction.

[0028] The anode gas inlet manifold 36 (anode gas inlet flow path 32) and the anode gas distribution manifold 42 (anode gas distribution flow path 44) are connected, for example, via an anode gas connection manifold 48 (defining an anode gas connection flow path 50). As shown in Fig. 2, this anode gas connection manifold 48 (anode gas connection flow path 50) is provided corresponding to the central portion (central stage portion) in the stacking direction of the cell stack 2 (plurality of battery cells 20), and this anode gas connection manifold 48 (anode gas connection flow path 50) is connected to a portion of the anode gas distribution manifold 42 (anode gas distribution flow path 44) that corresponds to the central portion (central stage portion) in the stacking direction of the plurality of battery cells 20.

[0029] The stack body 30 is further provided with a cathode gas inlet flow path 54 that communicates with the cathode gas supply flow path 6, and an anode offgas outlet flow path 56 that communicates with the anode offgas discharge flow path 10. In this embodiment, the cathode gas inlet flow path 54 is made up of a cathode gas inlet distribution manifold 58, which extends in the stacking direction of the multiple battery cells 20. The cathode offgas outlet flow path 56 is made up of a cathode offgas outlet manifold 60, which extends in the stacking direction of the multiple battery cells 20.

[0030] The cathode gas inlet distribution manifold 58 is provided with cathode gas inlet flow paths 62 (see Figure 4) at intervals in the stacking direction of the plurality of battery cells 20, corresponding to each of the cathode chambers 24 of the plurality of battery cells 20 in the cell stack 2, and the cathode off-gas outlet manifold 56 is provided with cathode gas outlet flow paths 64 (see Figure 4) at intervals in the stacking direction, corresponding to each of the cathode chambers 22 of the plurality of battery cells 20 in the cell stack 2.

[0031] In this cell stack 2, the anode gas supplied through the anode gas supply flow path 4 is delivered to the anode gas distribution manifold 42 (anode gas distribution flow path 44) through the anode gas inlet manifold 36 (anode gas inlet flow path 32) and the anode gas connection manifold 42 (anode gas connection flow path 44), as shown by the solid arrows in Figure 4, and is delivered from this anode gas distribution manifold 42 (anode gas distribution flow path 44) through the corresponding anode gas introduction flow path 46 to the anode chamber 22 of each battery cell 20.

[0032] At this time, the low-temperature anode gas is supplied to the anode gas distribution manifold 42 (anode gas distribution flow path 44) through the anode gas inlet manifold 34 (anode gas inlet flow path 32) and the anode gas connection manifold 42 (anode gas connection flow path 44). This allows the low-temperature anode gas to flow in the central portion of the cell stack 2 in the stacking direction (i.e., the central portion of the plurality of battery cells 20). This prevents the temperature from rising in the central portion of the cell stack 2 (the central portion of the plurality of battery cells 20), which is prone to temperature rise. Furthermore, the anode gas that has flowed into the anode gas distribution manifold 42 (anode gas distribution flow path 44) flows in the central portion of the cell stack 2 (i.e., the central portion of the plurality of battery cells 20), which is prone to temperature rise. As shown, the anode gas flows from a portion (portion connected to the anode gas connection manifold 48) of the anode gas distribution manifold 42 (anode gas distribution flow path 44) that corresponds to the central portion (central stage portion) in the stacking direction of the cell stack 2 to both end portions, and the anode gas heated during this flow is supplied to the anode 24 chamber of the corresponding battery cell 20 through the anode gas introduction flow path 46. By flowing the anode gas in this manner, the temperature of the anode gas introduction flow path 46 can be made uniform, and as a result, it is possible to avoid a shortage of anode gas supply (so-called fuel starvation) that occurs when the temperature in the central portion of the cell stack becomes high over time and the temperature distribution changes.

[0033] In addition, the cathode gas supplied through the cathode gas supply flow path 6 is sent to the cathode gas inlet distribution manifold 58 (cathode gas inlet flow path 54) as shown by the dashed arrows in Figure 4, and after being distributed in this cathode gas inlet distribution manifold 58 (cathode gas inlet flow path 54), it is sent to the cathode chamber 24 of each battery cell 20 through the corresponding cathode gas introduction flow path 62.

[0034] In each battery cell 20 of the cell stack 2, an electrochemical reaction occurs between the anode gas supplied to the anode chamber 22 through the anode gas supply passage 4, the anode gas inlet passage 32, and the anode gas distribution passage 44, and the cathode gas supplied to the cathode chamber 24 through the cathode gas supply passage 6, and electricity is generated by this electrochemical reaction.

[0035] 1, in this fuel cell system, the cell stack 2 and combustor 72 are housed in a high-temperature space 76 defined by a high-temperature module 74 whose outer surface is covered with a heat insulating material. Anode off-gas from the anode chamber 22 (see FIG. 4) of the battery cell 20 and cathode off-gas from the cathode chamber 24 (see FIG. 4) are sent to the combustor 72, where the anode off-gas is combusted. The heat of combustion maintains a high temperature inside the high-temperature module 74, and the combustion exhaust gas is discharged to the outside through a combustion exhaust gas discharge passage 78.

[0036] In conventional fuel cell systems, as the operating time increases, deterioration of the cell stack occurs over time, and the temperature of the cell stack 2, particularly the temperature of the battery cells 20 in the central portion (central section), tends to rise.When the temperature of these battery cells 20 rises, the viscosity of the anode gas flowing into the anode chamber 22 increases, and the inflow flow rate of the anode gas flowing into this anode chamber 22 decreases, which may result in an insufficient supply of anode gas (so-called fuel starvation).

[0037] In contrast, in the fuel cell system of this embodiment, as described above, the anode gas from the anode gas supply flow path 4 is delivered through the anode gas inlet flow path 32 and the anode gas connection flow path 44 to a portion of the anode gas distribution flow path 44 that corresponds to the central portion (central stage portion) in the stacking direction of the cell stack 2. This means that this low-temperature anode gas is delivered to the central portion (central stage portion) in the stacking direction of the cell stack 2, thereby suppressing the temperature rise in the central portion (central stage portion) of the cell stack 2, which is prone to temperature rise. Furthermore, the anode gas that flows into the anode gas distribution flow path 44 flows toward both ends, and the anode gas heated during this flow is delivered to the anode 24 chamber of the corresponding battery cell 20 through the anode gas introduction flow path 46. By flowing the anode gas in this manner, the temperature in the anode gas introduction flow path 46 can be made uniform, and a shortage of anode gas supply (so-called fuel starvation) can be avoided.

[0038] In the above-described embodiment, the anode gas inlet manifold 36 (anode gas inlet flow path 32) and the anode gas distribution manifold 42 (anode gas distribution flow path 44) are connected via the anode gas connection manifold 48 (anode gas connection flow path 50), but this anode gas connection manifold 48 (anode gas connection flow path 50) may be omitted, and the anode gas inlet manifold 36 (anode gas inlet flow path 32) may be directly connected to the anode gas distribution manifold 42 (anode gas distribution flow path 44).

[0039] Furthermore, in the above-described embodiment, the anode gas supplied to the anode chamber of the cell stack is used to equalize the temperature of the anode gas introduction flow path, but it is also possible to further equalize the temperature of the anode gas introduction flow path by using cathode gas supplied to the cathode chamber of the cell stack in addition to this anode gas.

[0040] 5 shows a cell stack in a second embodiment of a fuel cell system of the present invention. In this embodiment, a cell stack 2A includes a stack body 30A for supporting a plurality of battery cells 20. This stack body 30A is provided with an anode gas inlet flow path 32 that communicates with the anode gas supply flow path, and an anode off-gas outlet flow path 34 that communicates with the anode off-gas discharge flow path. The anode gas inlet flow path 32 is composed of an anode gas inlet manifold 36 that extends in the stacking direction of the plurality of battery cells 20, and anode gas introduction flow paths (not shown) are provided at intervals in this stacking direction corresponding to the anode chamber of each battery cell.

[0041] An anode gas distribution flow path 44 is provided in parallel to the anode gas inflow flow path 32, and this anode gas distribution flow path 44 is composed of an anode gas distribution manifold 42, and the anode gas distribution flow path 44 (anode gas distribution manifold 42) and the anode gas inflow flow path 32 (anode gas inflow manifold 36) are connected via an anode gas connection flow path 50 (anode gas connection manifold). The configuration on the anode gas inflow side may be the same as in the first embodiment described above.

[0042] As in the above-described embodiment, the anode off-gas outlet flow path 34 is configured from the anode off-gas outlet manifold 38, and this anode off-gas outlet manifold 38 is provided with anode gas extraction flow paths spaced apart in the stacking direction so as to correspond to the anode chambers of each battery cell.

[0043] The stack body 30A further includes a cathode gas inlet flow path 54A that communicates with the cathode gas supply flow path, a cathode gas distribution flow path 80 that distributes the cathode gas to multiple battery cells, and a cathode off-gas outlet flow path 56 that communicates with the cathode off-gas exhaust flow path.

[0044] In this second embodiment, the cathode gas inlet flow path 54A is composed of a cathode gas inlet manifold 58A, which extends in the stacking direction of the multiple battery cells. The cathode gas distribution flow path 80 is composed of a cathode gas distribution manifold 82 that extends in the stacking direction of the multiple battery cells. The cathode gas distribution manifold 82 is provided with cathode inlet flow paths spaced apart in the stacking direction to correspond to the cathode chambers of the multiple battery cells. The cathode offgas outlet flow path 56, as in the above-described embodiment, is composed of a cathode offgas outlet manifold 60, which is provided with cathode gas outlet flow paths spaced apart in the stacking direction to correspond to the cathode chambers of each battery cell.

[0045] In the second embodiment, the cathode gas inlet manifold 58A (cathode gas inlet flow path 54A) and the cathode gas distribution manifold 82 (cathode gas distribution flow path 80) are connected, for example, via a cathode gas connection manifold (cathode gas connection flow path 84). Similar to the anode gas connection manifold 48 (anode gas connection flow path 50) in the above-described embodiment, this cathode gas connection manifold (cathode gas connection flow path 84) is provided corresponding to the central portion (central stage portion) in the stacking direction of the cell stack 2 (plurality of battery cells), and this cathode gas connection manifold (cathode gas connection flow path 84) is connected to a portion of the cathode gas distribution manifold 82 (cathode gas distribution flow path 80) that corresponds to the central portion (central stage portion) in the stacking direction of the cell stack (plurality of battery cells).

[0046] 5, in the second embodiment, the anode gas distribution flow path 44 (anode gas distribution manifold 42) and the cathode gas distribution flow path 80 (cathode gas distribution manifold 82) extend parallel to the stacking direction of the multiple battery cells. A cathode gas introduction flow path (not shown) that communicates with the cathode chamber of the cell stack 2A is provided in this cathode gas distribution flow path 80 (cathode gas distribution manifold 82), and the cathode gas introduction flow path of each battery cell is provided adjacent to this anode gas introduction flow path.

[0047] In the second embodiment, the anode gas from the anode gas supply flow path is delivered through the anode gas inlet flow path 32 and the anode gas connection flow path 50 to a portion of the anode gas distribution flow path 44 that corresponds to the central portion (central stage portion) in the stacking direction of the cell stack. This low-temperature anode gas is delivered to the central portion (central stage portion) in the stacking direction of the cell stack, and then flows within the anode gas distribution flow path 44 from the central portion to both end portions. By flowing the anode gas in this manner, it is possible to equalize the temperature of the anode gas introduction flow paths (i.e., the inlets of the anode chambers) of the multiple battery cells.

[0048] In addition, in the second embodiment, the cathode gas from the cathode gas supply flow path is delivered through the cathode gas inlet flow path 54A and the cathode gas connection flow path 84 to a portion of the cathode gas distribution flow path 80 that corresponds to the central portion (central stage portion) in the stacking direction of the cell stack. This low-temperature cathode gas is delivered to the central portion (central stage portion) in the stacking direction of the cell stack and then flows from the central portion to both end portions within the cathode gas distribution flow path 80. This flow of cathode gas helps to equalize the temperature of the cathode gas inlet flow paths (i.e., the inlets of the cathode chambers) of the multiple battery cells. In this case, because the anode gas inlet flow path and cathode gas inlet flow path of each battery cell are located close to each other, the temperature equalization of the cathode gas inlet flow path also affects the temperature of the anode gas inlet flow path, resulting in even more uniform temperature in the anode gas inlet flow paths (inlets of the anode chambers) of the multiple battery cells.

[0049] In this embodiment, the cathode gas inlet manifold 58A (cathode gas inlet flow path 54A) and the cathode gas distribution manifold 82 (cathode gas distribution flow path 80) are connected via a cathode gas connection manifold (cathode gas connection flow path 84), but this cathode gas connection manifold (anode gas connection flow path 84) may be omitted and the cathode gas inlet manifold 58A (cathode gas inlet flow path 54A) may be directly connected to the cathode gas distribution manifold 82 (cathode gas distribution flow path 80).

[0050] Various embodiments of the solid oxide fuel cell system according to the present invention have been described above, but the present invention is not limited to these embodiments, and various changes and modifications are possible without departing from the scope of the present invention.

[0051] For example, in the above-described embodiment, the present invention has been described as being applied to a solid oxide fuel cell (SOFC) as a cell stack, but is not limited to this form and can be similarly applied to molten carbonate fuel cells (MCFC), phosphoric acid fuel cells (PAFC), and the like. [Explanation of symbols]

[0052] 2 Cell stack 4 Anode gas supply channel 6 Cathode gas supply channel 12 Fuel blower (anode gas supply means) 16 Air blower 20 battery cells 22 Anode chamber 24 Cathode chamber 32 anode gas inlet passage 34 Anode gas outflow channel 44 anode gas distribution channel 46 Anode gas inlet channel 54, 54A Cathode gas inlet passage 56 Cathode gas outflow channel 62 Cathode gas inlet channel 80 cathode gas distribution channel

Claims

1. A fuel cell system comprising: a cell stack in which a plurality of battery cells are stacked, each battery cell having an ion-conducting electrolyte layer, an anode disposed on one side of the electrolyte layer, and a cathode disposed on the other side of the electrolyte layer; an anode gas supply flow path for supplying anode gas to an anode chamber of the cell stack; a cathode gas supply flow path for supplying cathode gas to a cathode chamber of the cell stack; an anode gas supply means for supplying the anode gas; and a cathode gas supply means for supplying the cathode gas, the cell stack includes a stack body for supporting the plurality of battery cells, the stack body being provided with an anode gas inlet flow path into which anode gas flows from the anode gas supply flow path and an anode gas distribution flow path that distributes the anode gas, as well as a cathode gas inlet flow path into which cathode gas flows from the cathode gas supply flow path and a cathode gas distribution flow path that distributes the cathode gas; the anode gas inlet flow path and the anode gas distribution flow path extend in a stacking direction of the plurality of battery cells, and anode gas introduction flow paths communicating with anode chambers of the plurality of battery cells are provided in the anode gas distribution flow path at intervals in the stacking direction, the cathode gas inlet flow path and the cathode gas distribution flow path extend in a stacking direction of the plurality of battery cells, and the cathode gas distribution flow path is provided with cathode gas introduction flow paths that communicate with the cathode chambers of the plurality of battery cells and are spaced apart in the stacking direction; Furthermore, the cathode gas distribution flow path extends parallel to the anode gas distribution flow path in the stacking direction of the plurality of battery cells, and the cathode gas inlet flow path and the anode gas inlet flow path of the plurality of battery cells are arranged close to each other, anode gas from the anode gas inlet flow channel is supplied to the anode gas distribution channel from a portion corresponding to a central portion in the stacking direction of the plurality of battery cells, flows through the anode gas distribution channel to be distributed to both ends and then supplied to the anode chambers of the plurality of battery cells through the corresponding anode gas inlet flow channel; cathode gas from the cathode gas inlet flow channel is supplied to the cathode gas distribution channel from a portion corresponding to a central portion in the stacking direction of the plurality of battery cells, flows through the cathode gas distribution channel to be distributed to both ends and then supplied to the cathode chambers of the plurality of battery cells through the corresponding cathode gas inlet flow channel.

2. The fuel cell system described in claim 1, characterized in that the anode gas inlet flow path extends in the stacking direction parallel to the anode gas distribution flow path, the anode gas inlet flow path and the anode gas distribution flow path are connected via an anode gas connection flow path, the anode gas connection flow path is provided at a position corresponding to the central portion of the plurality of battery cells in the stack body, and the anode gas from the anode gas supply flow path is supplied to the anode gas distribution flow path through the anode gas inlet flow path and the anode gas connection flow path.

3. The fuel cell system described in claim 1, characterized in that the cathode gas inlet flow path extends in the stacking direction parallel to the cathode gas distribution flow path, the cathode gas inlet flow path and the cathode gas distribution flow path are connected via a cathode gas connection flow path, the cathode gas connection flow path is provided at a position corresponding to the central portion of the plurality of battery cells in the stack body, and the cathode gas from the cathode gas supply flow path is supplied to the cathode gas distribution flow path through the cathode gas inlet flow path and the cathode gas connection flow path.

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