Fuel cell

Abstract

To provide a technique capable of effectively suppressing or avoiding communication between circulation regions where different types of fluids circulate in a fuel cell, even if a defect of a seal that separates the regions occurs.SOLUTION: Provided is a fuel cell 1 including a cell 2 that includes a power generation section 4 including a fuel electrode, an air electrode, and an electrolyte, a frame 10 supporting the power generation section 4, and a pair of separators 20, 40 sandwiching the power generation section 4 and the frame 10 therebetween. The cell 2 includes: a fuel gas circulation region FR for the circulation of fuel gas; an oxidant gas circulation region OR for the circulation of oxidant gas; a coolant circulation region CR for the circulation of a coolant; two or more seal lines 50, 54a extending between two different circulation regions adjacent to each other among the circulation regions so that the two different circulation regions are isolated from each other; and one or more exhaust passages 60 isolated from the two different circulation regions by the two or more seal lines 50, 54a and communicating with the outside of the fuel cell 1.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a fuel cell. [Background technology]

[0002] Fuel cells are constructed as a stack of many cells. For example, a polymer fuel cell cell is constructed by sandwiching a membrane electrode assembly (MEA) as a power generating part supported by a frame or the like between separators. The separators are bonded to the frame or the like by adhesive or the like.

[0003] In the cell, the separators that sandwich the power generation section form a fuel gas flow region for flowing fuel gas to the fuel electrode, an oxidant gas flow region for flowing oxidant gas to the air electrode, and a coolant flow region for flowing coolant around the cell. Each of these fluid flow regions is composed of a manifold and a flow path formed in the separator and the frame.

[0004] For example, on the side of the separator facing the fuel electrode, in order to supply only fuel gas to the fuel electrode, the fuel gas flow area including the fuel gas manifold and the fuel gas flow path is sealed and isolated from the oxidizer gas manifold and the refrigerant manifold (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-129367 A Summary of the Invention [Problem to be solved by the invention]

[0006] Such seals are formed with adhesive or the like, but in the area where the fuel gas flow region and the refrigerant manifold are adjacent to each other, the seal may be partially deformed or peeled off due to a pressure difference between the fuel gas and the refrigerant. If a seal defect occurs due to such deformation, the fuel gas flow region and the refrigerant flow region may communicate through the defective area, and fuel gas may flow from the fuel gas flow region with a higher pressure to the refrigerant flow region with a lower pressure. It is necessary to prevent or suppress such a flow in advance.

[0007] The present specification provides a technique for effectively suppressing or avoiding communication between different types of fluid flow regions in a fuel cell even if a failure occurs in the seal that separates the different types of fluid flow regions. [Means for solving the problem]

[0008] The technology disclosed in this specification is embodied in a fuel cell. The fuel cell includes a cell including a power generation unit having a fuel electrode, an air electrode, and an electrolyte, a frame supporting the power generation unit, and a pair of separators sandwiching the power generation unit and the frame. The cell includes a fuel gas flow region for flowing a fuel gas, an oxidant gas flow region for flowing an oxidant gas, and a coolant flow region for flowing a coolant. The cell includes two or more seal lines extending between two different adjacent flow regions among these flow regions to separate the two different flow regions from each other. The cell also includes one or more exhaust paths separated from the two different flow regions by the two or more seal lines and communicating with the outside of the fuel cell.

[0009] According to the fuel cell disclosed in this specification, one or more exhaust channels are isolated from two different adjacent flow regions by a seal line and communicate with the outside. When a seal failure occurs in the seal line between the exhaust channel and one or both of the adjacent flow regions, a pressure difference occurs because the exhaust channel communicates with the outside of the fuel cell. Due to this pressure difference, the fluid in the flow region that communicates with the exhaust channel due to the seal failure flows into the exhaust channel and is directly discharged to the outside of the fuel cell. Therefore, even if a seal failure occurs, the two different flow regions are prevented or suppressed from communicating with each other, and the mixing of different fluids or the circulation to another adjacent flow region are prevented or suppressed.

[0010] Also, such fuel cells are useful where the fuel cells have seal lines formed from adhesive layers that are susceptible to adhesion failure or abnormalities during use. [Brief description of the drawings]

[0011] [Figure 1A] FIG. 2 is a plan view of the cell of the first embodiment as viewed from the separator on the fuel electrode side, showing the seal line and exhaust channel patterns on the side surface on the fuel electrode side in a see-through view. [Figure 1B] FIG. 1B is a cross-sectional view taken along line 1B-1B in FIG. 1A. [Diagram 2] FIG. 2A is a plan view of the cell from the separator on the air electrode side, showing the pattern of the seal lines and exhaust channels on the air electrode side, and FIG. 2B is a plan view of the cell from the separator on the fuel electrode side, showing the pattern of the seal lines and exhaust channels between the cells. [Diagram 3] FIG. 1A shows a state when a seal defect occurs in the seal line of a fuel gas flow region in a cell, and FIG. 1B shows a state when a seal defect occurs in the seal line of a coolant flow region in a cell. [Figure 4A] FIG. 11 is a plan view of a cell of a second embodiment as viewed from the separator on the fuel electrode side, showing the seal line and exhaust channel patterns on the side surface on the fuel electrode side in a see-through view. [Figure 4B] 4B is a cross-sectional view taken along line 4B-4B in FIG. 4A. [Diagram 5] 1A and 1B are diagrams showing a state in which a seal failure occurs in the seal line of a fuel gas flow region and the seal line of a coolant flow region in a cell. [Figure 6] 13(a) to 13(c) show other aspects of the exhaust channel etc. in the cell. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In one embodiment of the present disclosure, the two or more seal lines may be configured to seal and isolate the fuel gas flow region and the refrigerant flow region from each other, thereby preventing or suppressing the fuel gas from mixing with the refrigerant and flowing or accumulating together with the refrigerant.

[0013] In one embodiment of the present disclosure, the two or more seal lines may include three seal lines, and the one or more discharge paths may include two discharge paths that are isolated from two different flow regions by the three seal lines and are isolated from each other. In this way, two adjacent different flow regions can each have a discharge path, and the fluids flowing through the two different flow regions can each be discharged to the outside. Also, in this embodiment, the two discharge paths may be connected to an external unit of the fuel cell associated with the fluids flowing through the two different flow regions. In this way, the fluids discharged from the fuel cell can be treated by the associated external unit.

[0014] In one embodiment of the present disclosure, the two or more seal lines may have three seal lines isolating the fuel gas flow region and the coolant flow region from each other, and the one or more exhaust paths may have two exhaust paths that are isolated from the fuel gas flow region and the coolant flow region by the three seal lines and are isolated from each other, one of the exhaust paths isolated from the fuel gas flow region may be connected to a fuel gas circulation or exhaust system outside the fuel cell, and the other exhaust path isolated from the coolant flow region may be connected to a coolant circulation or exhaust system outside the fuel cell. In this way, the fuel gas is appropriately treated in the fuel gas circulation or exhaust system, and the coolant is appropriately treated, such as recovered and reused, in the coolant circulation or exhaust system.

[0015] In this specification, the fuel cell is not particularly limited, but may be, for example, a polymer electrolyte fuel cell (PEFC). In this specification, the fuel cell usually has at least the form of a laminate (stack) in which cells are stacked. The stack form is not particularly limited. The fuel cell is housed in a housing (stack case) as necessary. In addition to the fuel cell, the fuel cell system also includes a circulation and exhaust system for fuel gas, oxidant gas, coolant, etc. Such a circulation and exhaust system is configured by appropriately adopting various known configurations.

[0016] Hereinafter, an embodiment of a fuel cell according to the present disclosure will be described with reference to the accompanying drawings.

[0017] (First embodiment) 1 to 3 relate to a first embodiment. The first embodiment relates to a two seal line / one exhaust channel seal structure having two seal lines between two different fluid flow regions and one exhaust channel isolated by these seal lines. FIG. 1A shows a plan view of the cell as viewed from the fuel electrode side separator, and FIG. 1B shows a 1B-1B cross-sectional view in FIG. 1A. FIG. 2 shows other seal lines and exhaust channels of the cell, and FIG. 3 shows the action of the fuel gas flowing on the fuel electrode side of the cell.

[0018] 1A and 1B, a cell 2 of a fuel cell (PEFC) 1 includes a frame 10 that supports the outer periphery of a power generation section 4, a fuel electrode side separator 20, and an air electrode side separator 40. The separators 20, 40 are integrated by sandwiching the power generation section 4 and the frame 10 between them. For example, a fuel cell 1 is configured with a stack of these cells 2, and further includes a gas circulation and discharge system (not shown) that circulates and discharges a fuel gas and an oxidant gas, and a refrigerant circulation and discharge system (not shown) that circulates and discharges a refrigerant in the fuel cell 1 housed in a specified housing, and the like, and the like, are configured as a fuel cell system as a whole.

[0019] The power generation unit 4 uses an ion-conductive polymer membrane as an electrolyte and is formed as a membrane electrode assembly (MEA) that integrates a fuel electrode and an air electrode via the electrolyte. The power generation unit 4 generates electricity through an electrochemical reaction between hydrogen gas, which serves as a fuel gas supplied to the fuel electrode, and air, which serves as an oxidant gas supplied to the air electrode.

[0020] The frame 10 surrounds and supports the outer periphery of the power generation unit 4. The frame 10 is not particularly limited, but may be made of any suitable known material for this type of frame, such as a thermosetting resin, such as a phenolic resin or an epoxy resin, a thermoplastic resin, such as PVDF, or a rubber or thermoplastic elastomer, such as ethylene-propylene rubber.

[0021] The frame 10 has a power generation unit 4 in the center, and in edge regions E1, E2 on both sides in the longitudinal direction, manifolds H1, H2 for fuel gas, manifolds O1, O2 for oxidant gas, and manifolds C1, C2 for coolant are provided as through holes. Fuel gas is supplied to the manifolds H1, H2 from a fuel gas circulation and discharge system (not shown) and circulated therethrough. Oxidant gas is supplied to the manifolds O1, O2 from an oxidant gas circulation and discharge system (not shown) and circulated therethrough. Coolant is supplied to the manifolds C1, C2 from a coolant circulation and discharge system (not shown) and circulated therethrough.

[0022] Each of the separators 20, 40 has a rectangular shape having an outer shape substantially the same as that of the frame 10. Each of the separators 20, 40 includes manifolds H1, H2, manifolds O1, O2, and manifolds C1, C2.

[0023] Furthermore, on the side surfaces 20a, 40a of the separators 20, 40 facing the power generation section 4, gas flow paths 22, 42 are formed, which communicate with the manifolds H1, H2 and the manifolds O1, O2, respectively, for distributing the fuel gas and the oxidant gas to the fuel electrode and the air electrode, respectively. These gas flow paths 22, 42 are formed corresponding to the power generation section 4. Furthermore, on the side surfaces 20b, 40b of the separators 20, 40 corresponding to the other adjacent cells 2, refrigerant flow paths 44 are formed, which communicate with the manifolds C1, C2, respectively, for distributing the refrigerant between the cells 2. Although there is no particular limitation on such flow paths, they are formed, for example, by forming the separators 20, 40 into a wavy or corrugated shape.

[0024] The separators 20 and 40 are not particularly limited, and may be metal separators formed from a metal plate, or may be resin separators formed by mixing and forming a conductive material such as carbon with a resin. The metal separator is made of a material appropriately selected from known metal separator materials, such as a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, a titanium steel plate, or a titanium steel plate having a carbon film.

[0025] Next, the seal structure for circulating the fuel gas to the fuel electrode in the cell 2 will be described with reference to Fig. 1 etc. Note that Fig. 1A is a plan view, but clearly shows the seal line and exhaust channel pattern on the side surface 20a of the separator 20 facing the fuel electrode in a see-through manner.

[0026] 1A and 1B, a seal line 50 is formed between the side surface 20a of the separator 20 facing the power generation section 4 and the frame 10 and the power generation section 4 (hereinafter also referred to as the frame 10, etc.) to surround and seal the manifolds H1, H2 and the power generation section 4 to form a fuel gas flow region (hereinafter simply referred to as the fuel gas region) FR. Furthermore, between the same side surface 20a and the frame 10, etc., seal lines 52a, 52b are formed to surround the manifolds O1, O2 to form an oxidant gas flow region (hereinafter simply referred to as the oxidant gas region) OR, and seal lines 54a, 54b are formed to surround the manifolds C1, C2 to form a refrigerant flow region (hereinafter simply referred to as the refrigerant region) CR.

[0027] The seal lines 50, 52a, 52b, 54a, and 54b may be formed as seal parts between the separator 20 and the frame 10 to the extent that gas or refrigerant can be blocked between the power generation unit 4 and the side surfaces 20a and 20b of the separator 20 facing the power generation unit 4. Although not particularly limited, for example, as shown in FIG. 1B, the separator 20 is bent toward the frame 10 and the part is fixed to the frame 10 by an adhesive layer to form the seal line. Examples of such adhesives include epoxy resin, phenolic resin, and silicone resin. In addition, the adhesive layer may be formed by appropriately selecting from known seal materials such as various elastic seal materials such as EPDM, NBR, fluororubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, and acrylic rubber.

[0028] 1A, where the fuel gas flow FR and the refrigerant region CR are adjacent, two seal lines 50, 54a extend between these regions in roughly parallel fashion. Also, where the refrigerant region CR and the oxidant gas region OR are adjacent, two seal lines 54a, 52a extend between these regions in roughly parallel fashion. Similarly, where the fuel gas region FR and the oxidant gas region OR are adjacent, two seal lines 50, 52a extend between these regions in roughly parallel fashion.

[0029] 1A and 1B, the cell 2 is further provided with a discharge channel 60. The discharge channel 60 is formed between the seal lines 50, 54a extending in parallel (hereinafter also referred to as between the seal lines 50 / 54a) and between the seal lines 50 / 52a so as to communicate with the outside. The discharge channel 60 is isolated from the adjacent flow areas by the two seal lines 50, 54a and 50, 52a which are present on either side of the discharge channel 60.

[0030] As shown in Fig. 1A, the discharge passage 60 communicating with the outside is formed by communicating sub-discharge passages 60a, 60b, 60c, and 60d between the fuel gas region FR and the coolant region CR and the oxidant gas region OR. The sub-discharge passages 60a and 60b are formed between the fuel gas region FR and the coolant region CR and between the seal lines 50 / 54a. The sub-discharge passage 60c is formed between the coolant region CR and the oxidant gas region OR and between the seal lines 54a / 52a. The sub-discharge passage 60d is formed between the fuel gas region FR and the oxidant gas region OR and between the seal lines 50 / 52a.

[0031] The sub-discharge channels 60a, 60c, and 60d each have an end at an edge of the cell 2, and these ends each have openings 62a, 62c, and 62d that open toward the outside of the cell 2. The sub-discharge channels 60a to 60d are in communication with each other, so that the entire discharge channel 60 is in communication with the outside.

[0032] As shown in FIG. 1B, for example, the discharge path 60 is formed as a rising rib from the frame 10 together with the seal line 50 and the like by bending the separator 20 and forming it into an uneven shape.

[0033] The seal structure in the cell 2 has been described above with respect to the edge region E1, but also in the other edge region E2, the seal lines 50, 52b, 54b and the discharge path 60 are formed in a similar manner.

[0034] 2(a) shows the seal line pattern of the side surface 40a of the separator 40 on the air electrode side, and FIG. 2(b) shows the seal line pattern between the separators 20, 40. For example, as shown in FIG. 2(a), between the side surface 40a of the separator 40 and the frame 10, etc., there are formed a seal line 70 that surrounds and seals the manifolds O1, O2 and the power generation unit 4 to form an oxidant gas region OR, seal lines 72a, 72b that surround the manifolds H1, H2 to form a fuel gas region FR, and seal lines 74a, 74b that surround the manifolds C1, C2 to form a refrigerant region CR, in accordance with the side surface 20a on the fuel electrode side of the separator 20. Furthermore, a discharge path 80 is also formed.

[0035] Furthermore, as shown in FIG. 2(b), for example, between the separators 20, 40, there are formed a seal line 90 which surrounds and seals the manifolds C1, C2 and the refrigerant flow path 44 facing the power generation section 4 to form a refrigerant region CR, seal lines 92a, 92b which surround the manifolds H1, H2 to form a fuel gas region FR, and seal lines 94a, 94b which surround the manifolds O1, O2 to form an oxidant gas region OR, and further, a discharge path 100 is formed.

[0036] Next, the flow of fuel gas as an example of the flow of fluid in the cell 2 will be described with reference to Fig. 3. Fig. 3(a) and Fig. 3(b) correspond to the 1B-1B cross section of Fig. 1A shown in Fig. 1B. In the fuel cell 1, when a sealing failure occurs that causes a fluid to flow into the discharge path 60, a pressure difference is generated among the fuel gas region FR, the oxidant gas region OR, the coolant region CR, and the discharge path 60, as follows: fuel gas region FR>oxidant gas region OR>coolant region CR>discharge path 60.

[0037] When no sealing failure occurs at the seal lines 50, 54a between the side 20a of the separator 20 and the frame 10, the fuel gas region FR and the refrigerant region CR are isolated from each other, the flow areas of these different fluids are not connected, and no mixing of the different fluids occurs.

[0038] On the other hand, as shown in FIG. 3(a), for example, if a seal failure occurs only in the seal line 50 between the fuel gas region FR and the coolant region CR, causing communication between the fuel gas region FR and the sub-discharge path 60a, the fuel gas flows into the discharge path 60a due to the pressure difference between these mutually connected regions. The fuel gas is discharged to the outside of the fuel cell 1 through the openings 62a, 62c, and 62d. Therefore, communication between the fuel gas region FR and the coolant region CR does not occur. Note that even if a seal failure occurs only in the seal line 54a, causing communication between the coolant region CR and the discharge path 60a, the coolant only flows into the discharge path 60a and is discharged to the outside due to the pressure difference, and communication between the fuel gas region FR and the coolant region CR does not occur.

[0039] 3(b), when a seal failure occurs in both the seal lines 50, 54a between the fuel gas region FR and the refrigerant region CR, both the fuel gas and the refrigerant flow into the discharge passage 60a due to the pressure difference and are discharged to the outside through the openings 62a, 62c, 62d. Even if a seal failure occurs in the two seal lines 50, 54a, no communication is created between the fuel gas region FR and the refrigerant region CR.

[0040] Such a seal structure is particularly useful when the seal line is formed with an adhesive layer.

[0041] In the above description, the fuel gas region FR and the coolant region CR have been described, but the same effects are obtained for the seal line 52a / 54a and the exhaust path 60c between the oxidant gas region OR and the coolant region CR, and for the seal line 52a / 50 and the exhaust path 60d between the oxidant gas region OR and the fuel gas region FR. The same effects are obtained for the flow regions of these gases on the side surface 40a of the separator 40 facing the air electrode, and for the flow regions of these gases between the separators 20, 40.

[0042] As described above, by providing two seal lines 50, 54a, 52a, etc. that extend between two different regions of the regions FR, CR, and OR and isolate them from each other, and a discharge path 60 that is isolated from the two different flow regions by these seal lines 50, 54a, 52a, etc. and communicates with the outside of the fuel cell 1, even if a seal failure occurs, it is possible to avoid or suppress communication between adjacent flow regions. In addition, it is possible to effectively prevent the fuel gas from entering the coolant circulation discharge system and from circulating and accumulating in the coolant circulation discharge system.

[0043] In the first embodiment, the exhaust passage 60 is provided in all of the areas between two adjacent different flow areas among the fuel gas area FR, the coolant area CR, and the oxidant gas area OR, but this is not limited thereto. The area in which the exhaust passage is provided can be changed as necessary. For example, the exhaust passage may be provided only between the fuel gas area FR and the coolant area CR.

[0044] In the first embodiment, the sub-discharge paths 60a, 60c, and 60d constituting the discharge path 60 are provided with the openings 62a, 62c, and 62d that communicate with the outside, respectively, but this is not limited thereto. From the viewpoint of processing the fluid discharged from the openings 62a and the like, the discharge path 60 may be provided with one or two openings.

[0045] Second Embodiment 4 to 6 relate to the second embodiment. The second embodiment relates to a seal structure with three seal lines / two exhaust channels having three seal lines between two different fluid flow regions and two exhaust channels isolated from each other by these seal lines. FIG. 4A shows a plan view of the cell 2 seen from the fuel electrode side separator 20, FIG. 4B shows a cross section taken along line 4B-4B in FIG. 4A, and FIG. 5 shows the action of the cell 2 when the fuel gas flows on the fuel electrode side. Although FIG. 4A is a plan view, the seal lines and exhaust channel patterns on the fuel electrode side side 20a of the separator 20 are clearly shown in a see-through manner. In the following description, the structure common to the first embodiment will be omitted, and the members common to the first embodiment will be described using the same reference numerals. In the following description, only the portion of the cell 2 close to the edge region E1 will be described, and the edge region E2 will be omitted from the description as it is equivalent to the edge region E1.

[0046] 4A and 4B, the side surface 20a of the separator 20 is provided with a seal line 110 that surrounds and seals the manifolds H1, H2 and the power generation section 4 to form a fuel gas region FR. Furthermore, the side surface 20a is provided with a seal line 120 that surrounds the manifolds O1, O2 to form an oxidant gas region OR, and a seal line 130 that surrounds the manifolds C1, C2 to form a refrigerant region CR.

[0047] In this embodiment, the cell 2 includes an additional seal line 140. The seal line 140 extends along the seal line 110 between the fuel gas region FR and the coolant region CR and the oxidant gas region OR adjacent to the fuel gas region FR. For example, as shown in Fig. 4A and Fig. 4B, the seal line 140 specifically extends between the seal lines 110 and 130 and between the seal lines 110 and 120.

[0048] 4A, the three seal lines 110, 140, 130 extend generally parallel between the fuel gas region FR and the refrigerant region CR where these regions are adjacent to each other. Also, the three seal lines 110, 140, 120 extend generally parallel between the fuel gas region FR and the oxidant gas region OR where these regions are adjacent to each other.

[0049] As shown in Fig. 4A and Fig. 4B, the cell 2 has two exhaust channels 150, 160. The exhaust channel 150 is formed between the seal line 110 and the seal line 140 in the range where the additional seal line 140 is formed. The exhaust channel 160 is formed between the seal line 140 and the portions 130a, 120a of the seal lines 130, 120 adjacent to the fuel gas region FR, at least in the range where the additional seal line 140 is formed. The exhaust channel 150 is isolated from the adjacent fuel gas region FR by the seal line 110, and the exhaust channel 160 is isolated from the refrigerant region CR and the fuel gas region FR by the seal lines 130a, 120a. The exhaust channels 150, 160 are also isolated from each other by the seal line 140.

[0050] 4A, the discharge path 160 includes a branched and communicating sub-discharge path 162. The sub-discharge path 162 branches between the coolant region CR and the oxidant gas region OR and extends between a part of the seal line 130 adjacent to the oxidant gas region OR and a part of the seal line 120 adjacent to the coolant region CR. The sub-discharge path 162 is isolated from the coolant region CR and the oxidant gas region OR by parts of the seal lines 130, 120.

[0051] The seal lines 110, 120, 130, 140 and the discharge paths 150, 160 are formed as seal portions and ribs on the frame 10 by bending the separator 20 and forming it into an uneven shape, as shown in FIG. 4B, for example.

[0052] Here, as shown in FIG. 4A, the discharge channels 150, 160 each have a single opening 150a, 160a. As a result, the discharge channels 150, 160 each communicate with the outside of the cell 2. The opening 150a opens to the outside of the cell 2 at one end that reaches the long end edge of the cell 2. The other end of the discharge channel 150 that reaches the vicinity of the short end edge of the cell 2 is sealed. Also, the opening 160a opens only at one end that reaches the long end edge of the cell 2, and the other two ends that reach the vicinity of the short end edge of the cell 2 are sealed.

[0053] From the above, the discharge path 150 is isolated from the fuel gas region FR by the seal line 110 adjacent to this region, and functions as an outlet exclusively for fuel gas in the event of a seal failure. The discharge path 160 is isolated from the coolant region CR and the oxidant gas region OR by the seal lines 130, 120 adjacent to these regions CR, OR, and functions as a discharge path for the coolant and oxidant gas in the event of a seal failure.

[0054] An opening 150a of the discharge path 150 is connected to a ventilation device 200 that is part of a fuel gas circulation and discharge system installed outside the stack case that houses the stack, so that fuel gas leaking from the fuel gas region FR can be safely ventilated. Also, an opening 160a of the discharge path 160 is connected to a coolant tank 300 that is part of a coolant circulation and discharge system installed outside the stack case that houses the stack, so that the coolant and oxidant gas that flow into the discharge path 160 can be stored in the coolant tank 300.

[0055] As in the first embodiment, on the air electrode side of cell 2 and between cells 2, seal lines and exhaust paths are formed in accordance with the seal line pattern and exhaust path pattern of FIG. 4A, as shown in FIG. 2(a) and FIG. 2(b), which can suppress or avoid communication between the oxidant gas region OR and the refrigerant region CR, respectively.

[0056] Next, the flow of fuel gas in the seal structure of the cell 2 will be described with reference to Fig. 5. As shown in Fig. 5, when a seal defect occurs in one or both of the seal lines 110, 130, the fuel gas flows into the discharge path 150, and the refrigerant flows into the discharge path 160. The fuel gas is further supplied to the ventilation device 200 of the fuel gas circulation discharge system through the opening 150a, and the refrigerant is supplied to the refrigerant tank 300 of the refrigerant circulation discharge system through the opening 160a.

[0057] This makes it possible to avoid communication between the fuel gas region FR and the refrigerant region CR. Also, the fuel gas and refrigerant discharged from the cells 2 or stack are each appropriately treated outside the stack case. That is, the fuel gas and refrigerant leaking out and accumulating inside the stack case, which is outside the fuel cell 1, and the inconveniences caused by such accumulation (such as an increase in the fuel gas concentration inside the stack case, corrosion of other parts due to the refrigerant, and refrigerant leakage) are suppressed or avoided. Also, even if defects occur simultaneously in the seal line 110 of the fuel gas region FR and the seal line 130 of the refrigerant region CR, a mixture of the fuel gas and the refrigerant is not generated.

[0058] In addition, since the seal line 140 is not in contact with the fuel gas region FR, etc., the occurrence of a seal defect is avoided or suppressed even under a situation where a seal defect occurs in the seal lines 110, 130. Therefore, the generation of a mixture of the fuel gas and the refrigerant is sufficiently avoided or suppressed.

[0059] Furthermore, when a seal defect occurs in one or both of the seal lines 110, 120 at a location where the fuel gas region FR and the oxidant gas region OR are adjacent to each other, the oxidant gas flows from the oxidant gas region OR into the discharge path 160, and the fuel gas flows from the fuel gas region FR into the discharge path 150 and is discharged. This avoids or suppresses communication between the fuel gas region FR and the oxidant gas region OR and the generation of a mixture of these fluids.

[0060] Since there is only one opening 150a, 160a of the exhaust paths 150, 160 per edge region E1, the structure for connecting the fuel gas and coolant from the cell 2 or fuel cell 1 to the fuel gas circulation and exhaust system and the coolant circulation and exhaust system can be simplified.

[0061] In this embodiment, the exhaust passage 150 exhausts only fuel gas. Therefore, in addition to being connected to a ventilation unit of a fuel gas circulation system, it can also be connected to a fuel gas circulation unit. Furthermore, the opening 150a of the exhaust passage 150 can be provided with a hydrogen sensor to detect a seal failure of the seal line 110. Furthermore, the opening 150a can also be provided with a suction mechanism to suck in leaked fuel gas, either as part of the fuel gas circulation system outside the stack case or independently.

[0062] In this embodiment, the discharge path 160 discharges only the coolant and / or the oxidant gas. Even if the coolant and / or the oxidant gas from the discharge path 160 flows into the coolant circulation system outside the stack case, accumulation of the fuel gas in the closed coolant circulation system is prevented. In addition, the opening 160a can be provided with a sensor that detects the coolant so that a seal failure of the seal line 130 can be detected.

[0063] In the second embodiment described above, a seal structure with three seal lines and two exhaust paths is provided between the fuel gas region FR / coolant region CR and between the fuel gas region FR / oxidant gas region OR, and a seal structure with two seal lines and one exhaust path is provided between the oxidant gas region OR and the coolant region CR, but this is not limited to this. A seal structure with three seal lines and two exhaust paths may be provided as appropriate between two adjacent regions.

[0064] In the second embodiment, a similar seal structure is provided not only on the side surface 20a of the separator 20 but also on the side surface 40a of the separator 40 and between the cells 2, but this is not limited thereto. An appropriate seal structure is selected depending on the risk of a seal failure.

[0065] In the first and second embodiments described above, the discharge channel is formed by bending the separator 20 or the like to form a rib, but the present invention is not limited thereto. For example, as shown in FIG. 6(a) and FIG. 6(b), the discharge channel 420 may be formed by forming a through hole 10a in the frame 10 between the seal lines 400 / 410. Also, the discharge channels 430, 440 may be formed by forming recesses 10b on both sides of the frame 10. Also, when the discharge channel 600 is formed between the seal lines 500 / 510 between the cells 2, as shown in FIG. 6(c), the separators 20, 40 are welded while being molded into an uneven shape to form the seal lines 500, 510 and the discharge channel 600.

[0066] The above aspects have been described as a fuel cell and a fuel cell system, but according to the disclosure of this specification, the present invention can also be implemented as a method for suppressing leakage of one or more types selected from a fuel gas, an oxidant gas, and a refrigerant in a cell constituting a fuel cell, or a method for detecting such leakage.

[0067] Specific examples of the technology disclosed in this specification have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples exemplified above. The technical elements described in this specification or the drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technology exemplified in this specification or the drawings can achieve multiple objectives simultaneously, and achieving one of the objectives itself has technical utility. [Explanation of symbols]

[0068] 1: Fuel cell 2: Cell 4: Power generation section 10: Frame 20: Fuel electrode side separator 20a: Side of the fuel electrode separator facing the power generation section (fuel electrode) 40: Air electrode side separator 40a: Side of the air electrode separator facing the power generation section (air electrode) 50, 52a, 52b, 54a, 54b: Seal line 60: Exhaust channel 60a to 60d: Sub-exhaust passage 62a, 62c, 62d: opening 110, 120, 130, 140: Seal Line 150, 160: Discharge path 150a, 160a: opening 162: Sub-exhaust channel FR: Fuel gas flow area (fuel gas area) OR: Oxidant gas flow area (Oxidant gas area) CR: Refrigerant distribution area (refrigerant area)

Claims

1. 1. A fuel cell comprising: The fuel cell comprises a cell including a power generation unit having a fuel electrode, an air electrode, and an electrolyte, a frame supporting the power generation unit, and a pair of separators sandwiching the power generation unit and the frame; The cell is a fuel cell comprising: a fuel gas flow region for the flow of a fuel gas; an oxidant gas flow region for the flow of an oxidant gas; a coolant flow region for the flow of a coolant; two or more seal lines extending between two adjacent different flow regions among these flow regions to isolate the two different flow regions from each other; and one or more exhaust paths isolated from the two different flow regions by the two or more seal lines and communicating with the outside of the fuel cell.

2. 2. The fuel cell according to claim 1, wherein the two or more seal lines are configured to isolate the fuel gas flow region and the coolant flow region from each other.

3. 2. The fuel cell according to claim 1, wherein the two or more seal lines include three seal lines, and the one or more exhaust paths include two exhaust paths that are isolated from the two different flow areas by the three seal lines and are isolated from each other.

4. The fuel cell according to claim 3 , wherein the two exhaust passages are connected to units external to the fuel cell that are associated with fluids flowing through the two different flow regions, respectively.

5. the two or more seal lines include three seal lines that isolate the fuel gas flow region and the coolant flow region from each other, the one or more discharge paths include two discharge paths that are isolated from the fuel gas flow region and the coolant flow region by the three seal lines and are isolated from each other; 2. The fuel cell described in claim 1, wherein one of the exhaust paths isolated from the fuel gas flow area is connected to a fuel gas circulation and exhaust system outside the fuel cell, and the other of the exhaust paths isolated from the coolant flow area is connected to a coolant circulation and exhaust system outside the fuel cell.

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