JP2010287439A - Fuel cell and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell which can effectively utilize a non-power generation area outside a position corresponding to a gas supplying opening or gas discharging opening having a slender shape, which is formed in a separator, and is excellent in low-temperature stability; and to provide a control method thereof. <P>SOLUTION: The fuel cell 100 is constituted by laminating a unit fuel cell 10 including gas permeable layers disposed on both sides of a membrane-electrode assembly 3 and a separator 7 disposed on either one side of the gas permeable layers. Catalyst layers 2 and 2' (first catalyst layers) are formed in a central area corresponding to the inside between the gas supplying opening 71a and the gas discharging opening provided in the separator 7, and heating means (second catalyst layers 2a and 2'a) are disposed on the peripheral area outside the central area. The fuel battery further includes a control means for operating the heating means when the temperature within the cell is a preset temperature or lower. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell excellent in cold startability and a control method thereof.

  A fuel cell of a polymer electrolyte fuel cell has a membrane electrode assembly (MEA) formed from an ion-permeable electrolyte membrane and an anode-side and cathode-side catalyst layer sandwiching the electrolyte membrane. An electrode body (MEGA: Membrane Electrode & Gas Diffusion Layer Assembly) is formed from the membrane electrode assembly and the anode-side and cathode-side gas diffusion layers (GDL) sandwiching the membrane-electrode assembly, and a fuel gas or an oxidant is formed on the electrode body. A gas flow path layer made of a porous metal body for collecting gas and collecting electricity generated by an electrochemical reaction and a separator are arranged on both sides of the electrode body. In addition, the fuel cell in which the gas flow channel groove is formed in the separator is also a conventional one, and in this case, the metal porous body that becomes the gas flow channel layer is unnecessary. An actual fuel cell stack is formed by stacking and stacking a number of fuel cell cells according to required power.

  In the fuel cell described above, hydrogen gas or the like is provided as a fuel gas to the anode electrode, oxygen or air is provided as the oxidant gas to the cathode electrode, and each electrode has a unique gas flow path layer (or formed in a separator). The gas flows in the in-plane direction in the gas channel groove), and then the gas diffused in the gas diffusion layer is guided to the electrode catalyst layer to cause an electrochemical reaction.

  In the fuel cell described above, the electrode body includes a gasket for sealing a cooling medium such as a fuel gas and an oxidant gas supplied to the membrane electrode assembly, and a cooling water for suppressing a temperature rise of the cell. And formed on the periphery of the porous metal body by injection molding or compression molding. For example, in a fuel cell having a metal porous body serving as a gas flow path, one metal porous body on the anode side or cathode side is accommodated in the cavity of the mold, and then the electrode body is accommodated, and then the anode side or Gasket molding is performed by injecting a resin into the gasket forming cavity at the periphery of the electrode body and the metal porous body in a posture in which the other metal porous body on the cathode side is accommodated. There is also a method in which either the anode side or the cathode side separator is first accommodated in the cavity, and then the above-described constituent members are accommodated for injection molding.

  The separator described above has a three-layer structure in which a plate (intermediate layer, intermediate plate) in which a flow path is formed between two plates (cathode side plate and anode side plate) made of, for example, titanium or stainless steel is interposed. And the intermediate layer is made of a resin frame material, and a plurality of dimples and ribs defining a flow path are projected from one of the two plates to form a cooling water flow path (such as A structure can also be included in the separator having the three-layer structure), and a fuel cell including the separator having the three-layer structure is disclosed in Patent Document 1. The separator having this structure is either the anode side or cathode side separator of the cell itself, and at the same time the other separator on the anode side or cathode side of the adjacent cell in the stacking posture. That is, the cell constituent member of the fuel cell having this three-layer structure separator is composed of one three-layer structure separator and a gas permeable layer on the anode side and the cathode side (from a porous metal body such as expanded metal or metal foam sintered body). Gas passage layer) and an electrode body (membrane electrode assembly and gas diffusion layer), and in a posture in which a plurality of fuel cells are stacked, an arbitrary fuel cell has an anode side at both ends and It has a cathode side separator.

Here, in order to facilitate understanding of the three-layer structure separator, FIG. 4 shows a vertical cross-sectional view of a fuel cell having the three-layer structure separator.
In FIG. 4, in the fuel cell, a membrane electrode assembly c is formed from an electrolyte membrane a and cathode and anode catalyst layers b1 and b2 sandwiching the electrolyte membrane a. The membrane electrode assembly c is formed into a cathode side and an anode. The gas diffusion layers d1 and d2 on the side are sandwiched to form an electrode body e. The electrode body e is sandwiched between the gas flow layer f1 and f2 on the cathode side and the anode, and below the gas flow path layer f2 on the anode side. In addition, a separator h having a three-layer structure is disposed, and a gasket g including a fluid circulation manifold M is formed on the side of the electrode body e by injection molding or the like to constitute the whole. The three-layer separator h is interposed between two stainless steel or titanium first plates h1 (anode side plates), a second plate h2 (cathode side plates), and the plates h1 and h2. And an intermediate layer h3 (intermediate plate) that defines a flow path for fluid such as gas and cooling water. The fuel cell stack is formed by stacking a plurality of illustrated fuel cells and stacking them, and stacks fuel cells not shown in the figure above and below the illustrated fuel cells. .

  In the intermediate layer h3, an oxidant gas is introduced to provide an oxidant gas to a cathode-side gas flow path layer of a fuel cell (not shown) (a fuel cell located below the fuel cell shown). A path h3a (oxidant gas flow: Z1), a fuel gas introduction path h3b (fuel gas flow: Z2) for providing fuel gas to the anode-side gas flow path layer f2 of the illustrated fuel cell, and Is formed with a cooling flow path h3c through which a cooling medium for suppressing the temperature rise of the electrode body e in the course of power generation flows. FIG. 4 is a longitudinal sectional view cut along a section passing through the manifold M through which the oxidizing gas flows.

  By the way, in a fuel cell, a region where the catalyst layer is formed is generally a power generation region, and the ratio of the power generation region to the total area of the separator is called a power generation area utilization rate. It is required to be as high as possible.

  However, as is clear from FIG. 4, in the three-layer structure separator, there are structural restrictions (such as providing gas introduction paths, or supplying gas to the gas flow path layers unique to each of the oxidant gas and the fuel gas). An opening for supply (gas supply opening h1a for fuel gas, gas supply opening h2a for oxidant gas) and an exhaust opening (not shown) for exhausting gas from the gas flow path layer and the like are on the same side. For example, the catalyst layer forming region of the electrode body e can be provided only in the plane range in which the cooling channel through which the cooling medium flows is formed. More specifically, the anode-side gas supply opening h1a and the gas exhaust opening (not shown) are formed inside the cathode side gas supply opening h2a and the gas exhaust opening (not shown) in a plan view. In this case, the catalyst layer forming region (the central region in the drawing) is limited to the inner range of the gas supply opening h1a and the gas exhaust opening on the anode side. These openings effectively provide gas to the entire range of the gas flow path layer, and have the same width as the catalyst layer in order to efficiently exhaust gas from the gas flow path layer and the like. There is a form formed in an elongated shape as an extension, and such an elongated gas opening may be referred to as a so-called common rail.

JP 2008-123883 A

  While the catalyst layer formation region is limited for the above reasons, when the power generation region is temporarily expanded and this catalyst layer formation region is expanded not only to the central region but also to the outer peripheral region (and therefore at least the above) A catalyst layer is formed in a planar position corresponding to the common rails h1a and h2a and a region further outside thereof, and a gas flow path layer corresponding to the peripheral region (a cooling channel is provided at the corresponding position). Not formed), abnormal overheating occurs when a high-density current is applied, etc., and a hole that can become a gas cross-leakage path is opened in the electrolyte membrane, or dry-up is promoted by abnormal overheating, and local fuel cell There is a concern that a general power failure (power generation performance decline, power generation impossible) may occur.

  Furthermore, since the peripheral region described above is also a region into which the gas-rich oxidant gas and fuel gas introduced from the manifold M flows, the temperature tends to be higher than the central region of the electrode body during the power generation process. There is further concern about the occurrence of this.

  Therefore, instead of providing a catalyst layer in the peripheral region of the fuel cell described above to increase the power generation utilization area, the gas permeation layer (gas channel layer, gas diffusion layer, etc.) in this peripheral region has other functions. Therefore, an attempt to effectively use the area and verification are currently in progress.

  By the way, the above-described common rail has a relatively large opening area for supplying fuel gas or oxidant gas to the gas permeable layer or discharging the gas from the gas permeable layer to the outside. There is a problem that the generated generated water and the like block the common rail, and this is one of the important problems to be solved in this field.

  For example, when the fuel cell has a freezing atmosphere and the power generation of the fuel cell is stopped in such a posture that moisture stays in the common rail, the remaining moisture freezes and the common rail and separator gas introduction path, gas There is a concern that the discharge path or the like is blocked and, for example, gas supply to the fuel cell is hindered during start-up below freezing, resulting in start-up failure. In this case, it is considered that the cooling medium is also frozen in the same manner, and therefore there is a concern that the temperature rise of the electrode body cannot be suppressed by the cooling medium.

  The present invention has been made in view of the above-described problems, and effectively utilizes an unused area that does not contribute to power generation in a fuel cell, and a liquid (cooling water that is a cooling medium) present in the cell. It is an object of the present invention to provide a fuel cell excellent in low temperature startability in a low temperature atmosphere that can be frozen and a control method thereof.

  In order to achieve the above object, a fuel cell according to the present invention comprises a membrane electrode assembly formed of an electrolyte membrane and a catalyst layer contacting both sides of the electrolyte membrane, and a gas permeable layer on both sides of the membrane electrode assembly. A separator that provides either the fuel gas or the oxidant gas to the gas permeable layer is disposed on either gas permeable layer side to form a fuel cell, and the fuel cell The fuel cell is a laminated fuel cell, wherein the separator has a gas supply opening for supplying a fuel gas or an oxidant gas to a gas permeable layer on the anode side or the cathode side, and a gas on the anode side or the cathode side. A gas exhaust opening for discharging fuel gas or oxidant gas from the permeation layer is opened, and a catalyst layer is provided in a central region corresponding to the inside between the gas supply opening and the gas exhaust opening. Heating means is disposed in a peripheral region outside the central region of the fuel cell, and when the temperature in the cell is equal to or lower than a preset temperature, the heating means is It further comprises control means for operating.

  Here, the structure of the fuel cell described above is either a mode in which a gas diffusion layer composed of a diffusion layer base material and a current collecting layer is provided on both the anode side and the cathode side of the membrane electrode assembly, either the anode side or the cathode side. One of them includes both of the forms including only the current collecting layer (the diffusion layer base material is eliminated). In the present specification, any of these forms is referred to as an electrode body. In addition to a configuration in which separators having gas flow channel grooves formed on both sides of the electrode body are directly arranged, a gas flow channel layer (a porous metal such as an expanded metal) is formed between a so-called flat type separator and the electrode body. Body) is included. Furthermore, the “gas permeable layer” is meant to include both a gas diffusion layer and a gas flow path layer. Therefore, in a cell configuration that does not include a gas flow path layer, a “gas permeable layer” means a “gas diffusion layer”, and in a cell configuration that includes both a gas diffusion layer and a gas flow path layer, The “permeation layer” means either or both of “gas diffusion layer” and “gas flow path layer”.

  The fuel cell constituting the fuel cell of the present invention has a separator having, for example, a three-layer structure, and is provided in this separator, for supplying gas for supplying fuel gas and oxidant gas to the gas permeable layer. For example, in the case where these openings are formed in an elongated shape, corresponding to the central region between these openings. A catalyst layer on the anode side and the cathode side is formed in the electrode body to be heated, and a heating means is formed in, for example, a gas permeable layer (a gas flow path layer, a gas diffusion layer, etc.) in the peripheral region outside the central region. . That is, the heating means is arranged in the peripheral area of the cell structure that does not inherently contribute to power generation, the temperature of the cooling medium, for example, in the cell is sensed, and the reference temperature is determined based on the temperature at which the cooling medium freezes. (Preset temperature) In the following cases, the heating means arranged in the peripheral region is operated to raise the temperature in the cell, effectively preventing the cooling medium or the like from being frozen, or cooling that has already been frozen By rapidly melting the medium or the like, a fuel cell excellent in low-temperature startability is obtained.

  The term “low temperature startability” as used herein refers to the expected value of each fuel cell constituting the fuel cell stack as quickly as possible in a low temperature atmosphere where the cooling medium or the like existing in the cell can freeze. It refers to the performance that enables power generation.

  Here, examples of the heating means include a heating element and a small heater. Then, the measurement result obtained by the detection means such as a temperature sensor is sent to, for example, a control means (device) provided outside the fuel cell stack. An operation signal is transmitted to the means, and the heating element and the small heater generate heat. It should be noted that the sensing of the temperature sensor or the like is continued even after the operation of the heating means, and control is performed so that the operation of the heating means is stopped when the temperature inside the cell is not excessively increased, that is, when the temperature reaches a predetermined temperature. Preferably it is performed.

  In addition, as the “preset temperature”, when cooling water is used as the cooling medium, this temperature is set to zero degrees Celsius, which is the freezing point of water that temporarily closes the cooling water and the opening. It is possible to set the temperature slightly higher than the freezing point as this “preset temperature”, so that the freezing of the cooling medium can be surely suppressed.

  During the low temperature operation of the fuel cell stack, freezing of the cooling medium in the cell is suppressed by the heating means described above, or the already frozen cooling medium is melted and the cooling medium etc. is melted as quickly as possible. Above freezing temperature. Then, when the temperature equal to or higher than the freezing temperature is confirmed, the power generation of the fuel cell stack is performed. Needless to say, when the temperature in the cell is higher than the set temperature described above, the heating means is not operated and only the inherent power generation of the fuel cell stack is performed.

  According to the fuel cell according to the present invention described above, an appropriate heating means is arranged in the gas flow path layer in the peripheral region which is a non-power generation region of the fuel cell, which has not been used in the conventional structure, and this heating means is desired. Because the temperature inside the cell is quickly raised by controlling the temperature so that the liquid such as the cooling medium can be adjusted so as not to freeze, or if it is frozen, it can be melted immediately. It is possible to obtain a fuel cell excellent in low-temperature startability while effectively utilizing the unused area of the cell.

  In another embodiment of the fuel cell according to the present invention, the catalyst layer in the central region is a first catalyst layer, and a second catalyst insulated from the first catalyst layer is provided in the peripheral region. A first circuit in which a first catalyst layer is interposed, a second circuit in which a second catalyst layer is interposed, which serves as the heating means, and at least the second circuit. The switch further includes a switch for ON-OFF control of the circuit and an in-cell temperature detecting means, and the in-cell temperature detecting means detects that the temperature in the cell is equal to or lower than the preset temperature. At this time, at least the switch of the second circuit is controlled to be ON by the control means.

  In the present embodiment, a catalyst layer (second catalyst layer) separate from the central region catalyst layer (first catalyst layer) is also provided in the peripheral region, and the second catalyst layer is heated. It is intended to be used as

  For example, when a three-layer structure separator is applied, the refrigerant flow path exists in the central area, and the refrigerant flow path does not exist in the peripheral area. Therefore, when power generation is performed through the second catalyst layer, the temperature rise by the cooling medium cannot be achieved, so that the peripheral region naturally heats up. In the present embodiment, the fact that the peripheral region is not cooled by the cooling medium is effectively used, and this is used as a heating means to improve the low temperature startability of each fuel cell.

  The first circuit may also have a switch for ON / OFF control of the circuit, and the cell temperature detecting means detects that the temperature in the cell is equal to or lower than the preset temperature. In addition to the switch of the second circuit, the switch of the first circuit is also ON-controlled, and the temperature inside the cell is higher than the preset temperature. At the confirmed stage, introduction of fuel gas and oxidant gas into the cell may be executed, and power generation may be started.

  As a specific configuration of the above-described embodiment, a circuit including a first catalyst layer is used as a first circuit, and power generation by the fuel cell stack is executed in this circuit. The circuit including the catalyst layer is the second circuit, and this circuit is used only when the temperature in the cell (for example, the cooling medium) is equal to or lower than a preset temperature. At least the second circuit is provided with a switch (relay switch, transistor, etc.) whose ON / OFF can be controlled. The ON / OFF control of this circuit switch is performed by means of a temperature detecting means (for example, a temperature sensor) in the cell. ) Is controlled as desired by a control signal from the control means. In order to completely insulate the first and second circuits, an appropriate insulating material is interposed at least between the first and second catalyst layers. The in-cell temperature detecting means may be provided in the vicinity of the cooling medium inlet or in the vicinity of the outlet of the cooling medium manifold, or a gas introduction opening formed in the separator of each fuel cell. It may be provided in a gas exhaust opening or the like.

Here, in order to enhance the heating action of the second catalyst layer, it is preferable to make the resistance contributing to the heat generation of the second catalyst layer relatively larger than that of the first catalyst layer.
For example, the amount of the supported catalyst for forming the second catalyst layer is relatively small compared to the first catalyst layer, or the contact resistance between the gas passage layer of the first catalyst layer is compared with the first catalyst layer. Measures such as relatively increasing the contact resistance between the gas permeable layer and the second catalyst layer (thus reducing the surface pressure) can be given.

  In addition, the fuel cell control method according to the present invention comprises a membrane electrode assembly formed of an electrolyte membrane and a catalyst layer contacting both sides of the electrolyte membrane, and a gas permeable layer is disposed on both sides of the membrane electrode assembly. A separator that provides either the fuel gas or the oxidant gas to the gas permeable layer is arranged on either gas permeable layer side to form a fuel cell, and the fuel cell is stacked. The separator includes a gas supply opening for supplying fuel gas or oxidant gas to the anode- or cathode-side gas-permeable layer, and the anode- or cathode-side gas-permeable layer. A gas exhaust opening for discharging fuel gas or oxidant gas from the gas outlet is opened, and a catalyst layer is formed in a central region corresponding to the inside between the gas supply opening and the gas exhaust opening. A method for controlling the internal temperature of the fuel cell, wherein any one of the following steps is selected and executed, and when the temperature in the cell is equal to or lower than a preset temperature, Heating the heating means disposed at least in the peripheral region outside the central region of the fuel cell, and when the temperature in the cell is higher than a preset temperature, the central region of the fuel cell This step comprises the steps of generating power from the fuel cell through the catalyst layer and taking out the power.

  Furthermore, in another embodiment of the method for controlling a fuel cell according to the present invention, a second catalyst layer insulated from the first catalyst layer is formed in the peripheral region, and the first catalyst layer is interposed. A first circuit that serves as the heating means, a second circuit that includes a second catalyst layer, a control means that operates the heating means, and at least the second circuit. A control method for a fuel cell having a switch for ON-OFF control and an in-cell temperature detecting means, wherein the temperature in the cell is equal to or lower than the preset temperature by the in-cell temperature detecting means. When detected, at least the switch of the second circuit is controlled to be ON by the control means, and the temperature in the cell is higher than the preset temperature by the in-cell temperature detection means. Detected high temperature The, by the control means, the switch of the second circuit is OFF control, switch of the first circuit is what is adapted to be ON controlled.

  In the control method described above, when the temperature in the cell is equal to or lower than a preset temperature, in addition to heating the heating means, the fuel gas and the oxidant gas are not introduced into the cell. The first circuit is also ON-controlled, and when the temperature in the cell becomes higher than the preset temperature, introduction of fuel gas and oxidant gas into the cell is executed, A control method for starting power generation of the fuel cell may be used.

  By the above-described control method of the present invention, a fuel cell excellent in low-temperature startability is formed by controlling the temperature in the cell in a low-temperature atmosphere in which the liquid present in each fuel cell can be frozen. Is possible.

  As can be understood from the above description, according to the fuel cell of the present invention and the control method thereof, an appropriate heating means is disposed in the peripheral region that is a non-power generation region of the fuel cell that has not been used in the conventional structure, This heating means is controlled as desired so that the temperature in the cell can be raised quickly, so that adjustment can be made so that the liquid such as the cooling medium does not freeze or the cooling medium is frozen. It can be melted as quickly as possible. Therefore, the low temperature startability can be remarkably improved while effectively utilizing the unused area of the fuel cell.

It is the schematic diagram which looked at the fuel cell of this invention from the side. It is the longitudinal cross-sectional view which expanded a part of fuel cell which comprises the fuel cell of FIG. It is the flowchart explaining the control method of the fuel cell of this invention. It is the longitudinal cross-sectional view which expanded a part of embodiment of the fuel cell which comprises the conventional fuel cell.

  Embodiments of the present invention will be described below with reference to the drawings. The illustrated fuel cell is an enlarged view of the left side region, more specifically, only the region including the gas supply opening into which the fuel gas is introduced. It goes without saying that the right side region of the structure has a region having a gas exhaust opening. In order to make the description clearer, the illustration of the opening for supplying the oxidant gas and the like is omitted in FIG.

  FIG. 1 is a side view of a fuel cell according to the present invention. In the illustrated fuel cell 100, a desired number of fuel cells 10,... Are stacked to form a fuel cell stack, and terminal plates 20 and 20, insulating plates 30 and 30, and a total minus side end plate 40A are disposed outside them. The total plus side end plate 40B is arranged, and the whole is stacked through a tension plate (not shown), whereby the fuel cell 100 is formed. In each fuel cell 10, it goes without saying that an anode side electrode is formed on the total minus side and a cathode side electrode is formed on the total plus side.

  In the illustrated example, the heat insulating member 50 is disposed outside the total minus side end plate 40A, so that the heat retention performance of the total minus side end plate 40A can be more reliably ensured.

The total minus side SM of the fuel cell 100 faces end openings of the cooling medium supply pipe 60A and the cooling medium discharge pipe 60B, and flows through the cooling medium supply pipe 60A (Win in the X1 direction). (Cooling water or the like) flows in the in-plane direction (X2 direction) through a flow path (not shown) provided in, for example, a separator of each fuel battery cell 10, and cools the electrode body that generates heat in the course of power generation as desired. It is like that.
The cooling water that has flowed through each fuel cell 10 is drained to the coolant discharge pipe 60B (Wout) and discharged to the outside of the fuel cell 100 via the coolant discharge pipe 60B.

Here, the structure of each fuel cell 10 will be outlined with reference to FIG. FIG. 2 is an enlarged longitudinal sectional view of a part of the fuel cell constituting the fuel cell of FIG.
In the fuel cell 10 shown in FIG. 2, a membrane electrode assembly 3 is formed from the electrolyte membrane 1 and the catalyst layers 2 and 2 ′ on the cathode side and the anode side, which are formed into gas diffusion layers on the cathode side and the anode side. 4, 4 '(gas permeable layer) is sandwiched to form an electrode body 5, which is sandwiched between cathode and anode gas flow path layers 6, 6' (gas permeable layer, metal porous body), A separator 7 having a three-layer structure is arranged on the gas flow path layer 6 ′ side on the anode side.

  The catalyst layers 2, 2 ′ have a smaller area than the electrolyte membrane 1, and therefore the catalyst layers 2, 2 ′ do not exist at the periphery of the catalyst layers 2, 2 ′ on both sides of the electrolyte membrane 1. An exposed region 1a is formed, and a protective film (not shown) on the cathode side and the anode side is disposed in the exposed region 1a, and the fluff protruding from the gas diffusion layers 4 and 4 ′ pierces the exposed region of the electrolyte membrane 1. Is protected.

  Here, the electrolyte membrane 1 constituting the membrane electrode assembly 3 includes, for example, a fluorine ion exchange membrane having a sulfonic acid group or a carbonyl group, a substituted phenylene oxide, a sulfonated polyaryletherketone, a sulfonated polyarylethersulfone, It is formed from a non-fluorine polymer such as sulfonated phenylene sulfide.

  In addition, the catalyst layers 2 and 2 ′ are prepared by mixing a conductive carrier (particulate carbon carrier or the like) carrying a catalyst, an electrolyte, and a dispersion solvent (organic solvent) to form a catalyst solution (catalyst ink). The catalyst layer is formed by stretching it in a layer shape with a coating blade, for example, on a base material such as the electrolyte membrane 1 or the gas diffusion layers 4 and 4 'and drying it in a hot air drying furnace or the like. It is formed. Here, the electrolyte forming the catalyst solution is a proton conductive polymer, an ion exchange resin having a skeleton of an organic fluorine-containing polymer, such as a perfluorocarbon sulfonic acid resin, a sulfonated polyether ketone, a sulfonated polyether. Sulfonated plastic electrolytes such as sulfone, sulfonated polyetherethersulfone, sulfonated polysulfone, sulfonated polysulfide, sulfonated polyphenylene, sulfoalkylated polyetheretherketone, sulfoalkylated polyethersulfone, sulfoalkylated polyetherethersulfone And sulfoalkylated plastic electrolytes such as sulfoalkylated polysulfone, sulfoalkylated polysulfide, and sulfoalkylated polyphenylene. Examples of commercially available materials include Nafion (registered trademark, manufactured by DuPont) and Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.). Examples of the dispersion solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, and diethylene glycol, acetone, methyl ethyl ketone, dimethylformamide, dimethylimidazolidinone, dimethyl sulfoxide, dimethylacetamide, and N-methylpyrrolidone. , Propylene carbonate, esters such as ethyl acetate and butyl acetate, and various aromatic or halogen solvents, and these can be used alone or as a mixed solution. Furthermore, regarding a conductive carrier carrying a catalyst, examples of the conductive carrier include carbon materials such as carbon black, carbon nanotubes, and carbon nanofibers, and carbon compounds typified by silicon carbide. As this catalyst (metal catalyst), for example, any one of platinum, platinum alloy, palladium, rhodium, gold, silver, osmium, iridium, etc. can be used, preferably platinum or platinum alloy is used. It is good to do. Furthermore, as this platinum alloy, for example, platinum, aluminum, chromium, manganese, iron, cobalt, nickel, gallium, zirconium, molybdenum, ruthenium, rhodium, palladium, vanadium, tungsten, rhenium, osmium, iridium, titanium and lead An alloy with at least one of them can be mentioned.

  The gas diffusion layers 4 and 4 ′ are each composed of a diffusion layer base material and a current collecting layer (MPL), and the diffusion layer base material is particularly limited as long as it has a low electrical resistance and can collect current. For example, those mainly composed of conductive inorganic substances can be mentioned. Examples of the conductive inorganic substances include fired bodies from polyacrylonitrile, fired bodies from pitch, graphite, expanded graphite, and the like. Carbon materials, nanocarbon materials thereof, stainless steel, molybdenum, titanium, and the like. Further, the form of the conductive inorganic substance of the diffusion layer base material is not particularly limited. For example, the conductive inorganic substance is used in the form of fibers or particles, but is an inorganic conductive fiber from the viewpoint of gas permeability, and particularly carbon fiber. Is preferred. As the diffusion layer substrate using inorganic conductive fibers, a woven fabric or non-woven fabric structure can be used, and examples thereof include carbon paper and carbon cloth. The woven fabric is not particularly limited, such as a plain weave or a plain weave, and examples of the nonwoven fabric include a papermaking method and a water jet punch method. Further, examples of the carbon fiber include phenol-based carbon fiber, pitch-based carbon fiber, polyacrylonitrile (PAN) -based carbon fiber, and rayon-based carbon fiber. Furthermore, the current collecting layer serves as an electrode for collecting electrons from the catalyst layers 2 and 2 ′ on the anode side and the cathode side, and has a water repellent action for draining generated water and the like, and is a conductive material. It can be formed from platinum, palladium, ruthenium, rhodium, iridium, gold, silver, copper and their compounds or alloys, conductive carbon materials, fluororesin (PTFE), and the like.

  Further, the porous metal bodies 6 and 6 'can be formed from expanded metal or a metal foam sintered body, for example, a gas flow path from a foam sintered body of a metal material having excellent corrosion resistance such as titanium, stainless steel, copper, nickel, etc. A layer is to be formed.

  Further, the separator 7 having a three-layer structure is integrated by brazing or the like with the first and second plates 71 and 72 made of stainless steel or titanium and the intermediate layer 73 (intermediate plate) interposed therebetween. It has been done.

  In the intermediate layer 73 constituting the separator 7 shown in the figure, a fuel gas introduction path 73b for supplying fuel gas to the metal porous body 6 ′ on the anode side of the fuel battery cell which is a constituent element, and a stack of cells. In the posture, an introduction path 73a for supplying oxidant gas (in the Z1 direction) to the metal porous body 6 on the cathode side of an adjacent fuel cell not shown is formed. Furthermore, a cooling flow path 73c through which a cooling medium such as cooling water flows is formed. Here, in the intermediate layer 73, a cooling flow path 73c is formed in a region inside thereof, and in the intermediate layer 73, an introduction path 73b for fuel gas is formed, and the first plate 71 communicates therewith. Is formed with a gas supply opening 71a (also referred to as a common rail) for a fuel gas that is elongated in plan view, and the fuel gas is provided to the gas flow path layer 6 'through the common rail. (Z2 direction). The fuel gas provided to the gas flow path layer 6 ′ flows in the gas flow path layer 6 ′ in the in-plane direction (Z3 direction) and is provided to the gas diffusion layer 4 ′ at various points ( Z4 direction).

  The intermediate layer 73 is further provided with an introduction path 73a for the oxidant gas, and a gas supply opening 72a for the elongated oxidant gas formed in the second plate 72 communicating therewith is formed. Yes. Note that a fuel gas and oxidant gas discharge passage and a gas exhaust opening (not shown) are also formed in the right region of the fuel battery cell (not shown).

  Although not shown, in the exposed region at the periphery of the catalyst layer where the electrolyte membrane is not in close contact with the catalyst layer, fluff protruding from the gas diffusion layer is prevented from sticking into the electrolyte membrane, Furthermore, the protective polymer film which has the effect which reinforces an electrolyte membrane with respect to the gasket by which injection molding is carried out is adhere | attached. This protective polymer film is made of polytetrafluoroethylene, PVDF (polyvinyl difluoride), polyethylene, polyethylene naphthalate (PEN), polycarbonate, polyphenylene ether (PPE), polypropylene, polyester, polyamide, copolyamide, polyamide elastomer, polyimide, It is formed from polyurethane, polyurethane elastomer, silicone, silicon rubber, silicon-based elastomer or the like.

  The gasket 8 has an endless rib 8a surrounding the manifold M on the periphery of the manifold M at the end thereof. The outline of the molding method is as follows. A metal porous body 6 ′ on the anode side, an electrode body 5, and a metal porous body 6 on the cathode side are accommodated in this order in a mold (not shown), and the mold is closed. This is performed by a method of injecting resin into the gasket cavity (injection molding). Here, as the material of the gasket, methanol-resistant epoxy resin, epoxy-modified silicone resin, silicone resin, fluorine resin, urethane RTV rubber, butyl rubber resin, silicone RTV rubber, EPDM resin, etc. are used. it can.

  In the illustrated fuel cell 10, a central region contributing to power generation and an insulating region 9 that insulates a peripheral region that does not contribute to power generation are provided, and separate catalyst layers 2 a and 2 ′ a are formed in the peripheral region. Has been. That is, the catalyst layers 2 and 2 ′ are the first catalyst layers, the catalyst layers 2a and 2′a are the second catalyst layers, and the second catalyst layers 2a and 2′a form the heat generating means. To do.

  The insulating region 9 of the fuel cell 10 is formed across each constituent member such as a catalyst layer and a separator, and in the process of forming each constituent member, an appropriate insulating resin is filled and cured. The insulating region 9 is formed by a method such as forming only with an insulating metal material.

  As described below, the insulating region 9 is provided in the fuel cell 10 and at least the first catalyst layer 2, 2 ′ and the second catalyst layer 2 a, 2 ′ a are completely unenergized. It is possible to form an electric circuit consisting only of the central region and an electric circuit consisting only of the peripheral region.

  The second catalyst layers 2a and 2'a serve as heat generating means, and are provided to improve the low temperature startability of the fuel cell 100, so that they are compared to the first catalyst layers 2 and 2 '. In order to enhance the heat generation performance, the amount of the supported catalyst for forming the second catalyst layer 2a, 2'a is relatively reduced, or the contact resistance between the gas permeation layer of the second catalyst layer 2a, 2'a It is preferable to take measures such as increasing the relative pressure (thus reducing the surface pressure).

  Returning to FIG. 1, the fuel cell 100 of the present invention is insulated from the circuit K2 (second circuit) formed through the peripheral region of each fuel cell 10 with the circuit K2 and the insulating region 9 interposed therebetween. Circuit K1 (first circuit) formed through the central region of each fuel cell 10, and switches SW1 and SW2 are provided for executing energization control of each circuit K1 and K2. ing. A load device F2 is interposed in the second circuit K2, and an electric power extraction device F1 for extracting electric power generated by the fuel cell stack is interposed in the first circuit K1.

A temperature sensor SE (in-cell temperature detection means) is arranged inside the cooling medium discharge pipe 60B so that at least the temperature of the cooling medium such as cooling water can be sensed.
Measurement data from the temperature sensor SE is transmitted to the control device SG (control means), and on the basis of the measurement data, the control means SG performs ON / OFF control of the switches SW1 and SW2 of the circuits K1 and K2. It is like that.

  Although the illustration of the internal structure of the control device SG is omitted, the internal structure stores a known CPU, RAM, ROM, interface circuit, temperature measurement data acquisition unit, and “preset temperature” serving as a threshold value. A storage unit, a comparison operation unit that compares the preset temperature and temperature measurement data, and transmits an ON-OFF control signal to the switches SE1 and SE2 according to the result, and a structure connected by a bus or the like It has become.

  Next, a control method of the fuel cell 100 shown in FIG. 1 will be described based on the flowchart shown in FIG. It should be noted that here, the winter in which the cooling medium (cooling water) can be frozen, which is a condition in which the vehicle (hybrid vehicle, electric vehicle (including fuel cell vehicle)) in which the fuel cell 100 of the present invention is mounted is effective. Or it must be placed in a cold area.

First, the vehicle is stopped, and therefore the ignition of the vehicle is turned on (step S2) from the state where the fuel cell is stopped (this state is referred to as step S1 for the time being).
When the ignition is turned on, temperature measurement data from the temperature sensor SE is transmitted to the control device SG, where it is compared whether or not the in-cell temperature is equal to or lower than a preset temperature (step S3). This “preset temperature” can be set to zero degrees Celsius, which is the freezing point of the cooling water when cooling water is used as the cooling medium, or a temperature slightly higher than the freezing point. By setting this, it is possible to reliably prevent the cooling medium from freezing.

  As a result of the comparison, when it is determined that the temperature measurement data is equal to or lower than a preset temperature, only the switch SW2 of the circuit K2 is ON-controlled, or the circuit K1 is in an attitude not to provide gas to the fuel cell. Since both the switches SW1 are also ON-controlled, at least the second catalyst layers 2a and 2′a, which are heat generating means, can generate heat (when the switch SW1 is also turned on, the first catalyst layers 2 and 2 are heated. 'Can also be a heating means).

  Sensing by the temperature sensor SE is continued, the measurement data is transmitted to the control device SG at any time, the comparison with the set temperature is performed at any time (step S6), and the in-cell temperature becomes higher than the preset temperature. At this stage, the switch SW2 is turned off (step S7), and the heat generation ends. By also performing control for terminating such heat generation, the peripheral region is prevented from being overheated.

On the other hand, if the temperature in the cell is higher than the preset temperature in step S3, since there is no need for heat generation by the heat generating means, only the switch SW1 is ON-controlled (step S5), and fuel gas and oxidation The agent gas is introduced into the cell (step S8), power generation by the fuel cell 100 is performed, and power extraction is performed by the power extraction device F1 (step S9).
In addition, after the operation of the heat generating means is stopped in step S7, the same control flow as that after step S5 is followed.

  According to the illustrated fuel cell 100 of the present invention and its control method, a low temperature at which a cooling medium or the like existing in the cell can be frozen while effectively using an unused peripheral region as a heating means in a fuel cell having a conventional structure. Under the atmosphere, it is possible to form a state in which normal power generation of the fuel cell can be performed as quickly as possible regardless of whether or not the cooling medium is frozen (good low temperature startability).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention. For example, the illustrated common rail may be an oxidant gas introduction path, and a fuel gas common rail may be disposed inside the common rail.

DESCRIPTION OF SYMBOLS 1 ... Electrolyte membrane, 1a ... Overhanging place, 2, 2 '... Catalyst layer (1st catalyst layer), 2a, 2'a ... Catalyst layer (2nd catalyst layer, heat-generating means), 3 ... Membrane electrode Joined body, 4 ... gas diffusion layer on the cathode side (gas permeable layer), 4 '... gas diffusion layer on the anode side (gas permeable layer), 5 ... electrode body, 6 ... metal porous body on the cathode side (gas permeable layer, Gas flow path layer), 6 '... anode side metal porous body (gas permeable layer, gas flow path layer), 7 ... separator, 71 ... first plate (anode side plate), 71a ... gas supply opening (common rail) 72 ... second plate (cathode side plate), 73 ... intermediate layer (intermediate plate), 73a ... oxidant gas introduction passage, 73b ... fuel gas introduction passage, 73c ... cooling passage, 8 ... gasket , 9 ... Insulating region, 10 ... Fuel cell, 100 ... Fuel cell

Claims (11)

A membrane electrode assembly is formed from the electrolyte membrane and a catalyst layer that contacts both sides of the electrolyte membrane, and a gas permeable layer is disposed on both sides of the membrane electrode assembly, and on either gas permeable layer side, A fuel cell in which a separator that provides either the fuel gas or the oxidant gas to the gas permeable layer is disposed to form a fuel cell, and the fuel cell is laminated,
The separator has a gas supply opening for supplying fuel gas or oxidant gas to the anode or cathode gas permeable layer, and fuel gas or oxidant gas from the anode or cathode gas permeable layer. There is an opening for gas exhaust to discharge,
A catalyst layer is formed in a central region corresponding to the inside between the gas supply opening and the gas exhaust opening;
Among the fuel cells, a heating means is arranged in a peripheral area outside the central area, and a control means for operating the heating means when the temperature in the cell is equal to or lower than a preset temperature. A fuel cell further provided. The catalyst layer in the central region is a first catalyst layer;
A second catalyst layer insulated from the first catalyst layer is formed in the peripheral region,
A first circuit with a first catalyst layer interposed;
A second circuit interposing a second catalyst layer serving as the heating means;
A switch provided at least in the second circuit for ON-OFF control of the circuit;
A temperature detecting means in the cell,
When the in-cell temperature detecting means detects that the temperature in the cell is equal to or lower than the preset temperature, at least the switch of the second circuit is ON-controlled by the control means. The fuel cell according to claim 1. The first circuit also has a switch for ON-OFF control of the circuit,
When the in-cell temperature detecting means detects that the temperature in the cell is equal to or lower than the preset temperature, the switch in the first circuit is also ON-controlled in addition to the switch in the second circuit. It is supposed to
The fuel cell according to claim 2, wherein introduction of fuel gas and oxidant gas into the cell is performed when the temperature in the cell becomes higher than the preset temperature.   The fuel cell according to claim 2 or 3, wherein the temperature of the cooling medium in the cell is detected by the in-cell temperature detection means.   The fuel cell according to any one of claims 2 to 4, wherein a resistance contributing to heat generation of the second catalyst layer is relatively larger than that of the first catalyst layer.   The separator has a three-layer structure in which a first plate, an intermediate layer, and a second plate are stacked, and the elongated opening is formed in either the first plate or the second plate. The fuel cell according to any one of claims 1 to 5, wherein a cooling medium circulates at a position corresponding to the central region in the intermediate layer. The gas permeable layer is in any form of a gas diffusion layer, a gas flow path layer made of a metal porous body, a combination of the gas diffusion layer and the gas flow path layer,
The fuel cell according to any one of claims 1 to 6, wherein the gas permeable layers on both the anode side and the cathode side are formed of either the same form among the plurality of forms or different forms. A membrane electrode assembly is formed from the electrolyte membrane and a catalyst layer that contacts both sides of the electrolyte membrane, and a gas permeable layer is disposed on both sides of the membrane electrode assembly, and on either gas permeable layer side, A fuel cell is formed by arranging a separator that provides either the fuel gas or the oxidant gas to the gas permeable layer, and the fuel cell is laminated. A gas supply opening for supplying fuel gas or oxidant gas to the anode or cathode gas permeable layer, and for discharging the fuel gas or oxidant gas from the anode or cathode gas permeable layer. A method for controlling the internal temperature of a fuel cell, wherein a gas exhaust opening is opened and a catalyst layer is formed in a central region corresponding to an inner side between the gas supply opening and the gas exhaust opening.
Any one of the following steps is selected and executed, and the steps include:
When the temperature in the cell is equal to or lower than a preset temperature, at least heating the heating means disposed in the peripheral region outside the central region of the fuel cell,
A method of controlling a fuel cell, comprising the steps of: generating electric power of the fuel cell through the catalyst layer in the central region of the fuel cell and taking out the electric power when the temperature in the cell is higher than a preset temperature; . In the peripheral region, a second catalyst layer that is insulated from the first catalyst layer is formed, a first circuit in which the first catalyst layer is interposed, and a second catalyst layer that serves as the heating means A second circuit intervening, a control means for operating the heating means, a switch provided in at least the second circuit for ON-OFF control of the circuit, and an in-cell temperature detection means. A fuel cell control method comprising:
When the in-cell temperature detecting means detects that the temperature in the cell is equal to or lower than the preset temperature, at least the switch of the second circuit is ON-controlled by the control means. And
When the in-cell temperature detecting means detects that the temperature in the cell is higher than the preset temperature, the control means turns off the switch of the second circuit, and The fuel cell control method according to claim 8, wherein the switch of the first circuit is ON-controlled. When the temperature in the cell is equal to or lower than a preset temperature, in addition to heating the heating means, the first circuit is also ON-controlled in a posture not to introduce fuel gas and oxidant gas into the cell. Is supposed to
The fuel cell according to claim 9, wherein introduction of fuel gas and oxidant gas into the cell is executed when the temperature in the cell becomes higher than the preset temperature. Control method.   The fuel cell control method according to claim 9 or 10, wherein the temperature of the cooling medium in the cell is detected by the in-cell temperature detection means.

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