JP6349985B2 - Separator for fuel cell and fuel cell - Google Patents

Description

  The present invention relates to a fuel cell separator and a fuel cell.

  A fuel cell is generally used in the form of a stack in which a plurality of single cells are stacked and fastened. Each single cell has a membrane electrode assembly, a gas diffusion layer disposed on the surface of the membrane electrode assembly, and a separator disposed on the surface of the gas diffusion layer. When manufacturing the fuel cell stack, the members constituting the fuel cell stack are stacked, and then each member is fixed by a predetermined fixing member with a pressing force (fastening load) applied from the outside. . As a result, the fastening load is maintained in the fuel cell stack, and the contact resistance between the layers is kept low.

  In recent years, it has been proposed to use Ti (titanium) as a separator material mainly from the viewpoint of reducing the size and weight of fuel cells and reducing the cost. When Ti is used as the material for the separator, there is a problem that a passive film (TiO2) is formed on the Ti surface and the contact resistance may increase. In order to solve such a problem, a technique for suppressing the formation of a passive film on the surface of the Ti substrate by forming a TiOx layer on the surface of the Ti substrate is proposed ( For example, see Patent Document 1). Here, TiOx is an oxygen-deficient titanium oxide and includes TiO2.

International Publication No. 2010/038544 JP 2013-201000 A JP 2012-186176 A JP 2012-28045 A

  The inventor of the present application has found that the above conventional techniques have the following problems. Generally, the gas diffusion layer is formed of carbon cloth, carbon paper, or carbon felt, and its surface is not smooth. Therefore, each separator in the fuel cell stack receives a local load from the gas diffusion layer side. In the above conventional technique, when the separator receives a local load, a crack occurs in the TiOx layer on the separator surface, the Ti base material is exposed, a passive film is formed on the Ti base material surface, and contact resistance is reduced. There was a problem that it might increase. Furthermore, the load applied to each separator is repeated during stacking / fastening when manufacturing the fuel cell stack, temperature change during power generation, swelling / shrinkage of the electrolyte membrane, and the moving body (for example, fuel cell vehicle) mounted with the fuel cell. It may fluctuate due to vibration or shock accompanying movement. When the load applied to the separator fluctuates, the possibility of cracking in the TiOx layer on the separator surface is further increased. Thus, when using a separator having a TiOx layer formed on the surface of a Ti substrate, there is a problem that the contact resistance may increase due to cracking of the TiOx layer. In addition, conventional fuel cell separators are desired to be reduced in size, reduced in cost, resource-saving, easy to manufacture, and improved in usability.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.
According to one aspect of the present invention, a separator for a fuel cell is provided. The separator is a Ti (titanium) base material, a TiOx layer formed on the surface of the base material, and a layer containing carbon, and is disposed on at least a part of the surface of the TiOx layer. A protective layer that suppresses the occurrence of cracks in the layer and has conductivity, and when the separator is used in a fuel cell, the protective layer is at least a contact portion with the gas diffusion layer of the fuel cell. , And a portion in contact with a separator of another adjacent fuel cell.
According to this form of separator, since the generation of cracks in the TiOx layer can be suppressed by the protective layer that is a layer containing carbon, an increase in contact resistance caused by the cracks in the TiOx layer can be suppressed.
In addition, the present invention can be realized as the following forms.

(1) According to one aspect of the present invention, a separator for a fuel cell is provided. The separator is a Ti (titanium) base material, a TiOx layer formed on the surface of the base material, and a layer containing carbon, and is disposed on at least a part of the surface of the TiOx layer. And generation of cracks in the layer, and a layer having conductivity. According to the separator of this form, since the generation of cracks in the TiOx layer can be suppressed by the carbon-containing layer, an increase in contact resistance caused by the crack in the TiOx layer can be suppressed.

(2) In the separator of the above aspect, the carbon-containing layer may be disposed at least in a portion of the separator that should contact the gas diffusion layer of the fuel cell. According to the separator of this embodiment, since the generation of cracks in the TiOx layer can be suppressed at the contact portion where the cracks in the TiOx layer are likely to occur, the increase in contact resistance caused by the crack in the TiOx layer is effectively increased. Can be suppressed.

(3) In the separator of the above aspect, the carbon-containing layer may not be disposed in a specific region other than the region that should face the gas diffusion layer of the fuel cell in the separator, and the TiOx layer may be exposed. Good. According to the separator of this form, it is possible to suppress the occurrence of problems caused by disposing the carbon-containing layer in the specific region.

(4) In the separator according to the above aspect, the specific region may be a region in the separator that is to contact a seal member of the fuel cell. According to the separator of this form, the adhesion between the separator and the sealing member is ensured by suppressing the deterioration of the gas sealing performance by not disposing the carbon-containing layer in the region that should contact the sealing member in the separator. it can.

  A plurality of constituent elements of each aspect of the present invention described above are not indispensable, and some or all of the effects described in the present specification are to be solved to solve part or all of the above-described problems. In order to achieve the above, it is possible to appropriately change, delete, replace with another new component, and partially delete the limited contents of some of the plurality of components. In order to solve part or all of the above-described problems or to achieve part or all of the effects described in this specification, technical features included in one embodiment of the present invention described above. A part or all of the technical features included in the other aspects of the present invention described above may be combined to form an independent form of the present invention.

  The present invention can be realized in various forms other than the fuel cell separator. For example, the present invention can be realized in the form of a fuel cell including a separator, a fuel cell system including a fuel cell, a moving body including a fuel cell system, a manufacturing method thereof, and the like.

It is explanatory drawing which shows schematic structure of the fuel cell system 10 in embodiment of this invention. It is explanatory drawing which shows the detailed structure of the separators 40 and 50. FIG. It is explanatory drawing which shows an example of the experimental result which investigates the relationship between the fluctuation | variation of the load concerning the separators 40 and 50 in the single cell 140, and the contact resistance between the separators 40 and 50 and the gas diffusion layers 32 and 34. It is explanatory drawing which shows an example of the experimental result which investigates the relationship between the fluctuation | variation of the load concerning the separators 40 and 50 in the single cell 140, and the contact resistance between the separators 40 and 50 and the gas diffusion layers 32 and 34.

A. Embodiment:
FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system 10 according to an embodiment of the present invention. The fuel cell system 10 is mounted on a mobile body such as an automobile, for example, and outputs electric power used as a driving force for the mobile body in response to an output request from the mobile body.

  The fuel cell system 10 includes a polymer electrolyte fuel cell stack 100. In the fuel cell stack 100, an end plate 110, an insulating plate 120, a current collecting plate 130, a plurality of single cells 140, a current collecting plate 130, an insulating plate 120, and an end plate 110 are laminated in this order. Have a stack structure. When the fuel cell stack 100 is manufactured, the members constituting the fuel cell stack 100 are stacked, and then a tension plate (not shown) is applied with a predetermined pressing force (fastening load) applied from the outside. Both ends are fixed to each end plate 110 by bolts (not shown). Thereby, the fastening load is maintained in the fuel cell stack 100, and the state in which the contact resistance between the respective layers is low is maintained.

  Hydrogen as fuel gas is supplied to the fuel cell stack 100 from a hydrogen tank 150 that stores high-pressure hydrogen via a shut valve 151, a regulator 152, and a pipe 153. The fuel gas supplied to the fuel cell stack 100 is distributed to each single cell 140 via a fuel gas supply manifold (not shown) and used for power generation in each single cell 140. The fuel gas (anode off gas) that has not been used in each single cell 140 is collected via a fuel gas discharge manifold (not shown) and discharged to the outside of the fuel cell stack 100 via a discharge pipe 163. The fuel cell system 10 may have a recirculation mechanism that recirculates the anode off gas to the pipe 153 side.

  The fuel cell stack 100 is also supplied with air as an oxidant gas via the air pump 160 and the pipe 161. The oxidant gas supplied to the fuel cell stack 100 is distributed to each single cell 140 via an oxidant gas supply manifold (not shown) and used for power generation in each single cell 140. The oxidant gas (cathode off gas) that has not been used in each single cell 140 is collected via an oxidant gas discharge manifold (not shown) and discharged to the outside of the fuel cell stack 100 via a discharge pipe 154. The fuel gas and the oxidant gas are also called reaction gas.

  Further, the cooling medium cooled by the radiator 170 is supplied to the fuel cell stack 100 via the water pump 171 and the pipe 172. The cooling medium supplied to the fuel cell stack 100 is distributed to each single cell 140 via a cooling medium supply manifold (not shown) to cool each single cell 140. The cooling medium after cooling each single cell 140 is collected via a cooling medium discharge manifold (not shown) and circulates to the radiator 170 via a pipe 173. As the cooling medium, for example, water, antifreeze water such as ethylene glycol, air, or the like is used. In this example, water (also referred to as “cooling water”) is used as the cooling medium.

  Each unit cell 140 included in the fuel cell stack 100 has a cathode (cathode side catalyst layer) disposed on one surface of the electrolyte membrane and a surface on the other surface, as shown partially enlarged in the lower part of FIG. A membrane electrode assembly (hereinafter referred to as MEA) 30 in which an anode (anode side catalyst layer) is disposed, a cathode side gas diffusion layer 32 disposed on the cathode side surface of MEA 30, and an anode side surface of MEA 30 In addition, the laminate composed of the anode-side gas diffusion layer 34 is sandwiched between a pair of separators, that is, a cathode-side separator 40 and an anode-side separator 50.

  The electrolyte membrane included in the MEA 30 is a solid polymer membrane formed of a fluorine-based resin material, a hydrocarbon-based resin material, or the like, and has good proton conductivity in a wet state. Further, the cathode and anode included in the MEA 30 include, for example, platinum as a catalyst supported on carbon or an alloy made of platinum and other metals.

  The cathode side gas diffusion layer 32 and the anode side gas diffusion layer 34 (hereinafter also collectively referred to as gas diffusion layers 32, 34) are formed of, for example, carbon cloth, carbon paper, or carbon felt, while diffusing the reaction gas. While supplying to MEA30, the reaction gas discharged | emitted from MEA30 is moved toward a discharge manifold. In addition, since the gas diffusion layers 32 and 34 are formed with the material mentioned above, the surface is not smooth. In the present embodiment, the length of the anode side gas diffusion layer 34 (the length along the direction orthogonal to the stacking direction of the fuel cell stack 100, hereinafter the same) is longer than the length of the cathode side gas diffusion layer 32. That is, the MEA 30 is not supported by the cathode-side gas diffusion layer 32 but is supported only by the anode-side gas diffusion layer 34 at the periphery of each unit cell 140.

  The cathode side separator 40 and the anode side separator 50 (hereinafter, collectively referred to as separators 40 and 50) are formed of, for example, a press-molded metal material. The cathode side separator 40 has a corrugated section, and an oxidant gas flow channel groove 42 is formed between the cathode side separator 40 and the cathode side gas diffusion layer 32. The oxidant gas flow channel 42 is used for supplying the oxidant gas to the cathode side gas diffusion layer 32 and discharging the oxidant gas from the cathode side gas diffusion layer 32. Similarly, the anode-side separator 50 has a section having a corrugated cross section, and a fuel gas passage groove 52 is formed between the anode-side separator 50 and the anode-side gas diffusion layer 34. The fuel gas flow channel 52 is used for supplying fuel gas to the anode side gas diffusion layer 34 and discharging the fuel gas from the anode side gas diffusion layer 34. A cooling medium flow channel 54 for allowing a cooling medium to pass therethrough is formed between the cathode side separator 40 of one unit cell 140 and the anode side separator 50 of another adjacent unit cell 140. The configuration of the separators 40 and 50 will be described in detail later.

  A resin sealing member 38 is provided on the peripheral edge of the MEA 30. The seal member 38 is in close contact with the outer peripheral portion of the MEA 30 and is in close contact with the surfaces of the pair of separators 40 and 50 that are opposed to each other with the MEA 30 interposed therebetween. In the cell 140, leakage of reaction gas between the cathode side and the anode side (cross leak) is suppressed. Examples of the material of the sealing member 38 include adhesive PP (for example, Admer (registered trademark) manufactured by Mitsui Chemicals, Modic (registered trademark) manufactured by Mitsubishi Chemical), and thermoplastic resins such as adhesive olefin and adhesive ester. Further, a thermosetting resin or the like that secures adhesiveness based on hydrogen bonds is used.

  FIG. 2 is an explanatory diagram showing a detailed configuration of the separators 40 and 50. FIG. 2 shows a cross-sectional configuration of a portion of a region A1 facing the cathode side gas diffusion layer 32 in the cathode side separator 40, and a region A3 not facing the cathode side gas diffusion layer 32 and the anode side gas diffusion layer 34. The cross-sectional structure of this part is shown. The region A2 is a region that faces the anode side gas diffusion layer 34 but does not face the cathode side gas diffusion layer 32. FIG. 2 is a schematic diagram for clearly showing the configuration of each part, and does not accurately show the dimensions and configuration of each part.

  In the region A1, the cathode separator 40 includes a Ti (titanium) base layer 44, TiOx layers (oxygen-deficient titanium oxide layers) 46 formed on both surfaces of the base layer 44, and a TiOx layer. The protective layer 48 is disposed on the surface opposite to the side facing the base material layer 44 of 46. The TiOx layer 46 is formed, for example, by performing a predetermined acid treatment on the surface of the Ti base layer 44 as described in International Publication No. 2010/038544. Since the TiOx layer 46 is formed so as to cover the surface of the base material layer 44, a passive film (TiO 2) is formed on the surface of the base material layer 44 to increase the contact resistance of the cathode side separator 40. Suppress.

  The protective layer 48 is formed by applying a rubber-based resin containing C (carbon) to the surface of the TiOx layer 46 by spraying or the like. Examples of rubber-based resins containing C (carbon) for forming the protective layer 48 include EPDM (ethylene propylene diene rubber) and PIB (polyisobutylene rubber), graphite, amorphous carbon, and an adhesive such as epoxy. Can be employed in which organic solvents are mixed. Moreover, as a material which comprises the protective layer 48, metals, such as silver and copper, can also be employ | adopted. As C (carbon) to be contained in the protective layer 48, graphite carbon, resin-containing carbon, or the like may be employed.

  Since the protective layer 48 contains C, it has conductivity. Moreover, since the protective layer 48 contains C, it becomes a relatively hard layer. Since such a protective layer 48 is formed so as to cover the surface of the TiOx layer 46, a local load is applied to the cathode-side separator 40 from the cathode-side gas diffusion layer 32 whose surface is not smooth. Even if the load fluctuates, the load applied to the TiOx layer 46 and the load fluctuation can be received by the protective layer 48, and the generation of cracks in the TiOx layer 46 can be suppressed. An increase in resistance can be suppressed.

  In addition, since the load from the cathode side gas diffusion layer 32 side is applied to the contact part with the cathode side gas diffusion layer 32 in the cathode side separator 40, in area | region A1, the protective layer 48 is the cathode in the cathode side separator 40 at least. What is necessary is just to be formed in the contact part with the side gas diffusion layer 32. FIG. However, for ease of manufacturing, as shown in FIG. 2, a portion other than the contact portion with the cathode-side gas diffusion layer 32 on the surface of the cathode-side separator 40 facing the cathode-side gas diffusion layer 32 (oxidation) The protective layer 48 may also be formed on a portion that constitutes the surface of the agent gas flow channel 42.

  Similarly, for the anode side separator 50, the protective layer 48 is formed at least in a contact portion with the anode side gas diffusion layer 34 in the region A <b> 1. Further, for the sake of easy manufacturing, a portion other than the contact portion with the anode gas diffusion layer 34 on the surface of the anode separator 50 facing the anode gas diffusion layer 34 (the surface of the fuel gas channel groove 52) The protective layer 48 may also be formed on the portion constituting the layer.

  Similarly, at the contact portion between the cathode separator 40 of one unit cell 140 and the anode side separator 50 of another adjacent unit cell 140, the TiOx layer 46 may be cracked due to load fluctuation. There's a problem. For this reason, in the present embodiment, the protective layer 48 is also formed in the region A1 at the contact portion of the cathode side separator 40 with the anode side separator 50. In order to facilitate manufacturing, as shown in FIG. 2, a protective layer 48 may be formed on the entire surface of the cathode side separator 40 opposite to the side facing the cathode side gas diffusion layer 32. Further, the protective layer 48 may be formed not on the cathode side separator 40 but on the anode side separator 50. Alternatively, the protective layer 48 may be formed on both the cathode side separator 40 and the anode side separator 50.

  On the other hand, in the region A <b> 3, the cathode separator 40 is composed of a Ti base layer 44 and TiOx layers 46 formed on both surfaces of the base layer 44. That is, in the region A3, the protective layer 48 is not formed on the cathode side separator 40, and the TiOx layer 46 is exposed. Therefore, in the region A3, the TiOx layer 46 is cracked in response to the above-described local load or fluctuating load, and a passive film may be formed on the surface of the Ti base layer 44. . However, since the region A3 is a region that does not face the cathode-side gas diffusion layer 32 and the anode-side gas diffusion layer 34, and is a region that hardly contributes to power generation, a passive film is temporarily formed on the surface of the base material layer 44. Even if formed, the impact on power generation performance is very limited. In addition, the region A3 is a region that adheres to the sealing member 38 and ensures the gas sealing property of the single cell 140. However, if the protective layer 48 is provided in this region, the protective layer 48 is in a high potential state. By peeling off, the gas sealing performance by the sealing member 38 may be reduced. In the present embodiment, the protective layer 48 is not formed in the region A3, and the TiOx layer 46 having relatively high adhesiveness with the seal member 38 is exposed, so that good adhesion with the seal member 38 is ensured, A decrease in gas sealability can be suppressed. In particular, the sealing member 38 formed of the above-described material has better adhesion to the TiOx layer 46 than the layer containing C (protective layer 48). Therefore, in the region A3, it is possible to ensure good gas sealing performance by positively exposing the TiOx layer 46. The configuration of the anode separator 50 in the region A3 is the same as the configuration of the cathode separator 40. The region A3 corresponds to a specific region in the claims.

  Note that, since the region A1 is not a portion that adheres to the sealing member 38, even if the protective layer 48 is peeled off, the gas sealing performance is not deteriorated.

  Further, the region A2 that faces the anode-side gas diffusion layer 34 but does not face the cathode-side gas diffusion layer 32 is not a region that greatly contributes to power generation, nor is a region where it is essential to ensure gas sealing performance. Therefore, whether or not the protective layer 48 is formed can be arbitrarily determined in the region A2. For example, in the region A2, as in the region A1, the protective layer 48 may be formed on the cathode side separator 40 and the anode side separator 50. Similarly to the region A3, the cathode side separator 40 is also formed on the anode side separator 50. However, the protective layer 48 may not be formed. Alternatively, the cathode-side separator 40 may not be formed with the protective layer 48 as in the region A3, and the anode-side separator 50 may be formed with the protective layer 48 as in the region A1.

  The protective layer 48 is preferably formed by using a rubber-based resin (C + rubber-based adhesive) to absorb the change in thickness. The thickness of the protective layer 48 may be sufficient to protect the TiOx layer 46, and is preferably 50 μm or less, and more preferably 10 μm or less.

  3 and 4 are examples of experimental results for examining the relationship between the load variation applied to the separators 40 and 50 in the single cell 140 and the contact resistance between the separators 40 and 50 and the gas diffusion layers 32 and 34. FIG. It is explanatory drawing shown. In the experiment, the load applied in the stacking direction of the single cells 140 was gradually increased, and then the cycle of decreasing the load was repeated four times (n1 to n4), and the contact resistance at each stage was measured. FIG. 3 shows an experimental result in a comparative example in which the TiOx layer 46 of the separator is exposed without being covered with the protective layer 48, and FIG. 4 shows a configuration in which the TiOx layer 46 of the separator is covered with the protective layer 48. The experimental result in embodiment is shown.

  As shown in FIG. 3, in the comparative example without the protective layer 48, the contact resistance greatly increased with each load increase / decrease cycle. This is presumably because cracks occurred in the TiOx layer 46 on the separator surface due to load fluctuations, and a passive film was formed on the surface of the base material layer 44. On the other hand, in the embodiment in which the TiOx layer 46 is covered with the protective layer 48, the amount of increase in contact resistance is negligible even after a similar load increase / decrease cycle. From this experimental result, by providing the protective layer 48 as in the above-described embodiment, even when the load applied to the separator fluctuates, the crack of the TiOx layer 46 is suppressed, and the increase in contact resistance is suppressed. It became clear to play.

  As described above, the fuel cell separators 40 and 50 of the present embodiment are disposed on the surface of the Ti base layer 44, the TiOx layer 46 formed on the surface of the base material layer 44, and the surface of the TiOx layer 46. In addition, since the conductive protective layer 48 that suppresses the generation of cracks in the TiOx layer 46 is provided, the generation of cracks in the TiOx layer 46 caused by local loads and load fluctuations can be suppressed. , 50 can be prevented from increasing in contact resistance.

  Further, in the fuel cell separators 40 and 50 of the present embodiment, the protective layer 48 is disposed at least in a portion that should contact the gas diffusion layers 32 and 34 in the separators 40 and 50. It is possible to effectively suppress the generation of cracks in the TiOx layer 46 due to local loads and load fluctuations received from 34, and to effectively suppress increase in contact resistance of the separators 40 and 50.

  Further, in the fuel cell separators 40 and 50 of the present embodiment, the protective layer 48 is not disposed in a region (specific region) other than the region that should face the gas diffusion layers 32 and 34 in the separators 40 and 50, and the TiOx layer 46. Therefore, it is possible to suppress the occurrence of problems caused by disposing the protective layer 48 in the specific region. For example, in the present embodiment, the specific region is a region that should contact the seal member 38 in the separators 40 and 50. By not providing the protective layer 48 in the region of the separators 40 and 50 that should contact the seal member 38, the adhesiveness between the separators 40 and 50 and the seal member 38 is ensured, and the deterioration of the gas sealability can be suppressed. .

B. Variations:
The configuration of the fuel cell system 10 in the above embodiment is merely an example, and the configuration of the fuel cell system 10 can be variously changed. For example, in the above embodiment, the protective layer 48 is a layer containing C, but the protective layer 48 may be a layer containing Au (gold). The protective layer 48 containing Au is a relatively soft layer. When the surface of the TiOx layer 46 is covered with such a protective layer 48, even if a local load is applied to the separators 40 and 50 or such a load fluctuates, the protective layer 48 having a relatively soft structure is formed. It functions like a cushion, and the load applied to the TiOx layer 46 and the fluctuation of the load are alleviated. Therefore, even if the configuration of the protective layer 48 is changed to a configuration including Au, it is possible to suppress the generation of cracks in the TiOx layer 46 as in the above-described embodiment. An increase in contact resistance can be suppressed. Further, the configuration of the protective layer 48 may be other configurations as long as it has conductivity and functions to suppress the occurrence of cracks in the TiOx layer 46.

  Further, in the above embodiment, in the region A1, the protective layer 48 is formed at least in contact portions with the gas diffusion layers 32 and 34 in the separators 40 and 50. However, the protective layer 48 in the separators 40 and 50 is used. The formation position of can be arbitrarily set as long as it is on at least a part of the surface of the TiOx layer 46. For example, the protective layer 48 is not formed in the contact portions of the separators 40 and 50 with the gas diffusion layers 32 and 34, and the anode-side separator 50 (or the cathode-side separator 40) in the cathode-side separator 40 (or the anode-side separator 50). ) May be formed at the contact portion. Even if it does in this way, by forming the protective layer 48, it can suppress that a crack generate | occur | produces in the TiOx layer 46, and can suppress the increase in the contact resistance of the separators 40 and 50. FIG.

  Moreover, in the said embodiment, although the protective layer 48 is not formed in the part located in area | region A3 in the separators 40 and 50, the protective layer 48 may be formed also in the part located in area | region A3.

  Further, in the above embodiment, the length of the anode side gas diffusion layer 34 is longer than the length of the cathode side gas diffusion layer 32, but conversely, the length of the cathode side gas diffusion layer 32 is the anode side gas diffusion layer 34. It may be longer than. Alternatively, the length of the anode side gas diffusion layer 34 and the length of the cathode side gas diffusion layer 32 may be the same.

  In the above embodiment, the fuel cell stack 100 is of a solid polymer type, but the present invention is also applicable to fuel cell stacks 100 of a type other than the solid polymer type. In the above embodiment, hydrogen is used as the fuel gas and air is used as the oxidant gas. However, other gases may be used as the fuel gas and the oxidant gas. In the above embodiment, the fuel cell system 10 is used while being mounted on a moving body. However, the fuel cell system 10 is not necessarily mounted on a moving body, and is installed on a fixed object such as the ground or a building. May be. Moreover, the material and shape of each member demonstrated in the said embodiment are an example to the last, and can be variously changed.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

10 ... Fuel cell system 30 ... MEA
32 ... Cathode side gas diffusion layer 34 ... Anode side gas diffusion layer 38 ... Seal member 40 ... Cathode side separator 42 ... Oxidant gas flow channel 44 ... Base material layer 46 ... TiOx layer 48 ... Protective layer 50 ... Anode side separator 52 ... Fuel gas passage groove 54 ... Cooling medium passage groove 100 ... Fuel cell stack 110 ... End plate 120 ... Insulating plate 130 ... Current collecting plate 140 ... Single cell 150 ... Hydrogen tank 151 ... Shut valve 152 ... Regulator 153 ... Piping 154 ... Discharge piping 160 ... Air pump 161 ... Piping 163 ... Discharge piping 170 ... Radiator 171 ... Water pump 172 ... Piping 173 ... Piping

Claims (4)

A separator for a fuel cell,
A base material made of Ti (titanium);
A TiOx layer formed on the surface of the substrate;
A layer containing carbon, said disposed on at least a portion of the surface of the TiOx layer, and suppress the occurrence of cracking of the TiOx layer, Bei example a protective layer having conductivity, a,
When the separator is used in a fuel cell, the protective layer is disposed at least in a contact portion with a gas diffusion layer of the fuel cell and a contact portion with a separator of another adjacent fuel cell. , Separator. The separator according to claim 1 ,
The separator having a portion in which the carbon-containing layer is not disposed and the TiOx layer is exposed in a specific region other than a region that should face the gas diffusion layer of the fuel cell in the separator. The separator according to claim 2 ,
The said specific area | region is a separator which is an area | region which should contact the sealing member of the said fuel cell in the said separator. A fuel cell,
A membrane electrode assembly;
A gas diffusion layer disposed on the surface of the membrane electrode assembly;
A separator disposed on the surface of the gas diffusion layer,
The separator is
A base material made of Ti (titanium);
A TiOx layer formed on the surface of the substrate;
A layer containing carbon, is disposed on at least a portion of the surface of the TiOx layer, and suppress the occurrence of cracking of the TiOx layer, seen including a protective layer, a having conductivity,
The said protective layer is a fuel cell arrange | positioned at least in the contact part with the gas diffusion layer of the said fuel cell, and the contact part with the separator of another adjacent fuel cell.

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