JP2008243747A - Fuel cell device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell device capable of efficiently separating gas in liquid, and with power generation efficiency improved. <P>SOLUTION: The fuel cell device includes an electromotive part having an anode and a cathode and generating power by chemical reaction, a fuel tank, and a circulation system supplying fuel and air to the electromotive part. The circulation system includes a fuel flow channel 22 for circulating the fuel through the anode of the electromotive part, a gas flow channel 24 for supplying air through the cathode, and a gas-liquid separator 40 provided between an outflow edge of the electromotive part and a fuel tank in the fuel flow channel and separating the liquid and gas. The gas-liquid separator, formed of a porous material, includes a first surface in contact with gas-liquid two-phase flow exhausted from the anode and a second surface in contact with gas supplied from the gas flow channel, as well as a gas permeable film 46 permeating gas in the gas-liquid two-phase flow. The fuel cell device is provided with a temperature control part 62 for controlling a temperature difference between the gas-liquid two-phase flow flowing into the gas-liquid separator and the separator at a desired value or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell device that includes a gas-liquid separator and is used as a power source for electronic equipment and the like.

  Currently, secondary batteries such as lithium ion batteries are mainly used as power sources for portable notebook personal computers (hereinafter referred to as notebook PCs) and mobile devices. In recent years, a small fuel cell with high output and no need for charging has been expected as a new power source due to an increase in power consumption accompanying the enhancement of functions of these electronic devices and a request for longer use. There are various types of fuel cells. In particular, a direct methanol fuel cell (hereinafter referred to as DMFC) using a methanol solution as a fuel is easier to handle than a fuel cell using hydrogen as a fuel. Since the system is simple, it is attracting attention as a power source for electronic devices.

  Usually, the DMFC includes a fuel tank in which methanol is stored, a liquid feed pump that pumps methanol to the electromotive unit, an air pump that supplies air to the electromotive unit, and the like. The electromotive unit includes a cell stack in which a plurality of single cells each having an anode and a cathode are stacked, and generates electricity by a chemical reaction by supplying methanol to the anode side and air to the cathode side. As reaction products accompanying power generation, unreacted methanol and carbon dioxide gas are generated on the anode side of the electromotive section, and water is generated on the cathode side. The reaction product water is exhausted as steam.

  In the gas-liquid two-phase flow of unreacted fuel and carbon dioxide generated at the anode, carbon dioxide inhibits the power generation reaction. Therefore, when the unreacted fuel generated at the anode is circulated and reused, it is necessary to separate and remove the gas component in the gas-liquid two-layer flow. Therefore, a gas-liquid separator is provided in the flow path extending between the anode outlet of the electromotive unit and the fuel tank. Unreacted methanol and carbon dioxide generated on the anode side of the electromotive section are sent to a gas-liquid separator, and methanol and carbon dioxide are separated. After the separation, methanol is sent to the fuel tank through the recovery channel, and carbon dioxide gas is sent to the cathode channel through the exhaust channel (for example, Patent Document 1).

There are various types of gas-liquid separators, but gas-liquid separators that are resistant to tilting conditions and are suitable for downsizing are proposed to be composed of a tube made of a porous gas-permeable membrane. (For example, patent document 2). The tube is disposed across the flow of the liquid, and the inside is decompressed by an exhaust device. Thereby, the gas contained in the liquid is exhausted into the tube through the tube of the gas-liquid separation membrane and separated from the liquid.
JP-A-2005-108718 Japanese Patent Laid-Open No. 4-4002

  In the fuel cell device configured as described above, the fuel separated by the gas-liquid separator is returned to the fuel tank and is used again for power generation. Therefore, in order to efficiently use the fuel, the gas-liquid separator provided between the electromotive unit and the fuel tank needs to be able to efficiently and reliably separate the fuel and the carbon dioxide gas.

  However, gas-liquid separation using a gas-permeable membrane is generally a method that pushes gas out of the system through the membrane using the pressure difference between the membranes. If it adheres, the separation rate decreases. Examples of the adhering substance include water condensed by condensation of water vapor in the separation gas. The anode fuel circulation system of the fuel cell device has a relatively high temperature, and the gas separated by the gas-liquid separator contains a lot of water vapor immediately after the separation. Therefore, when the separated gas is cooled, water vapor is condensed and adheres to the surface of the gas permeable membrane constituting the gas-liquid separator. And this dew condensation fills the hole of the gas permeable membrane and closes the gas passage. As a result, the gas-liquid separation efficiency of the gas-liquid separator decreases.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a fuel cell device capable of efficiently separating gas in a liquid and having improved power generation efficiency.

  In order to achieve the above object, a fuel cell device according to an aspect of the present invention includes a cell having an anode and a cathode, an electromotive unit that generates electric power by a chemical reaction, a fuel tank that contains fuel, and the fuel tank. A circulation system having a fuel flow path for circulating the supplied fuel through the anode of the electromotive section; a gas flow path for supplying air through the cathode of the electromotive section; and the electromotive force within the fuel flow path. A gas-liquid separator, which is provided between an outflow end of an electric part and the fuel tank, and separates liquid and gas. The gas-liquid two-phase flow formed of a porous material and discharged from the anode A gas-liquid separator having a first surface in contact with the second surface in contact with air supplied from the gas flow path, and having a gas permeable membrane that transmits gas in a gas-liquid two-phase flow; The gas-liquid two-phase flow flowing into the liquid separator and the It includes a temperature control unit for controlling a temperature difference below a predetermined value of the liquid separator, a.

  According to the above configuration, it is possible to reduce the temperature difference between the gas-liquid two-phase flow flowing into the gas-liquid separator and the gas-liquid separator, prevent condensation of the permeate gas, and prevent a decrease in gas-liquid separation efficiency. it can. Thereby, the gas in a liquid can be isolate | separated efficiently and the fuel cell apparatus with improved electric power generation efficiency can be provided.

Hereinafter, a fuel cell device according to a first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 schematically shows a circulation system configuration of a fuel cell device. As shown in FIG. 1, the fuel cell device 10 is configured as a DMFC using methanol as a liquid fuel. The fuel cell device 10 includes a cell stack 12 that constitutes an electromotive unit, a fuel tank 14, a circulation system 20 that supplies fuel and air to the cell stack, and a battery control unit 51 that controls the operation of the entire fuel cell device. Yes.

  The fuel tank 14 has a sealed structure, and contains high-concentration methanol as a liquid fuel. The fuel tank 14 may be formed as a fuel cartridge that is detachable from the fuel cell device 10.

  The circulation system 20 includes an anode flow path (fuel flow path) 22 for circulating the fuel supplied from the fuel supply port 14 a of the fuel tank 14 through the cell stack 12, and a cathode flow path for circulating a gas containing air through the cell stack 12. (Air channel) 24, having a plurality of auxiliary devices provided in the anode channel and in the cathode channel. The anode channel 22 and the cathode channel 24 are each formed by piping or the like.

  FIG. 2 shows the laminated structure of the cell stack 12, and FIG. 3 schematically shows the power generation reaction of each cell. As shown in FIG. 2 and FIG. 3, the cell stack 12 includes a laminate formed by alternately laminating a plurality of, for example, four single cells 140 and five rectangular plate-like separators 142, and a laminate. It has a frame 145 that supports the body. Each single cell 140 includes a substantially rectangular plate-like cathode (air electrode) 36 and an anode (fuel electrode) 37 each composed of a catalyst layer and carbon paper, and a substantially rectangular high electrode sandwiched between the cathode and anode. A membrane / electrode assembly (MEA) integrated with the molecular electrolyte membrane 144 is provided. The polymer electrolyte membrane 144 is formed in a larger area than the anode 37 and the cathode 36.

  The three separators 142 are stacked between two adjacent single cells 140, and the other two separators are stacked at both ends in the stacking direction. The separator 142 and the frame 145 are formed with a fuel channel 146 that supplies fuel to the anode 37 of each unit cell 140 and an air channel 147 that supplies air to the cathode 36 of each unit cell.

  As shown in FIG. 3, the supplied fuel and air chemically react with the electrolyte membrane 144 provided between the anode 37 and the cathode 36, thereby generating electric power between the anode and the cathode. The electric power generated in the cell stack 12 is supplied to an external device or the like via the battery control unit 51.

  As shown in FIG. 1, the auxiliary device provided in the anode flow path 22 is connected to the fuel supply port 14a of the fuel tank 14 through the piping via the on-off valve 26, the fuel pump 28, and the output portion of the fuel pump. A connected mixing tank 30 is provided. Further, the auxiliary machine includes a liquid feed pump 34 connected via a liquid filter 32 to an output portion of a mixing tank 30 that constitutes a part of the fuel tank. The output part of the liquid feed pump 34 is connected to the fuel flow path 146 of the cell stack 12 via the anode flow path 22.

  The output part of the anode 37 of the cell stack 12 is connected to the input part of the mixing tank 30 through the anode flow path 22. A gas-liquid separator 40 is provided in the anode flow path 22 between the output part of the cell stack 12 and the mixing tank 30. Exhaust fluid discharged from the anode 37 of the cell stack 12, that is, a gas-liquid two-phase flow containing an unreacted aqueous methanol solution that has not been used for a chemical reaction and generated carbon dioxide, is sent to a gas-liquid separator 40, where The carbon dioxide is separated. The separated aqueous methanol solution is returned to the mixing tank 30 through the anode channel 22 and supplied to the anode 37 again. The carbon dioxide separated by the gas-liquid separator 40 is sent to the harmful substance removal filter 56 through the cathode channel 24 described later.

  On the other hand, the upstream end 24a and the downstream end 24b of the cathode channel 24 communicate with the atmosphere. The auxiliary machine provided in the cathode channel 24 is connected to the cathode channel between the air filter 50 provided in the vicinity of the upstream end 24a of the cathode channel 24 on the upstream side of the cell stack 12, and between the cell stack 12 and the air filter. The air supply pump 52, the open / close valve 53, the exhaust filter 54 provided in the vicinity of the downstream end 24b of the cathode flow path 24 on the downstream side of the cell stack 12, and the open / close valve 55 are included.

  The air filter 50 captures and removes dust in the air sucked into the cathode channel 24, impurities such as carbon dioxide, formic acid, fuel gas, methyl formate, and harmful substances. The exhaust filter 54 detoxifies the by-product in the gas exhausted from the cathode flow path 24 to the outside, and captures the fuel gas contained in the exhaust gas.

  The gas-liquid separator 40 is connected to the cathode channel 24 between the inflow side of the cell stack 12 and the on-off valve 53. Further, a harmful substance removal filter 56 is provided in the cathode flow path 24 between the gas-liquid separator 40 and the inflow side of the cell stack 12. The gas sent from the gas-liquid separator 40 to the cathode flow path 24 passes through the harmful substance removal filter 56, where impurities and harmful substances such as fuel gas are removed and then sent to the cell stack 12.

Next, the gas-liquid separator 40 will be described in detail. FIG. 4 shows the gas-liquid separator 40 in an enlarged manner.
As shown in FIG. 4, the gas-liquid separator 40 includes a separation tube 42 that defines a part of the anode flow path 22, and a hollow container 44 provided so as to cover the separation tube 42. Yes. The separation tube 42 is formed by forming a gas permeable membrane 46 made of a porous material, for example, a porous fluorine-based resin and having a thickness of 1 to 2 mm into a cylindrical shape. The flow path through which the gas-liquid two-phase flow flows is defined by the inner surface (first surface) of the gas permeable membrane 46, and the outer surface of the separation tube 42 is formed by the outer surface (second surface). The gas permeable membrane 46 permeates the gas in the gas-liquid two-phase flow that flows in the flow path.

  Both end portions of the separation tube 42 are connected to pipes 22 a forming the anode flow path 22, respectively. Thereby, the separation tube 42 constitutes a part of the anode flow path 22 through which the exhausted fluid discharged from the anode 37, that is, the gas-liquid two-phase fluid containing the unreacted methanol aqueous solution and the generated carbon dioxide flows.

  The container 44 is provided so as to cover the entire separation tube 42, and defines a sealed space 60 in contact with the outer surface of the separation tube 42. The container 44 is connected to the cathode flow path 24 between the harmful substance removal filter 56 and the on-off valve 53. A pipe 24 c defining the cathode flow path 24 is connected to the container 44, and a space 60 in the container 44 communicates with the cathode flow path 24. Thereby, the outside air (air) supplied from the air supply pump 52 is supplied to the space 60 in the container 44 and flows around the separation tube 42, and then is sent to the cathode 36 through the harmful substance removal filter 56.

  According to the gas-liquid separator 40 configured as described above, the discharged fluid discharged from the anode 37 flows through the separation tube 42, and the outer surface of the separation tube 42 is the outside air supplied to the space 60, that is, It is in contact with air. The discharged fluid is relatively hot and has a pressure higher by several K Pascals than the outside air. Therefore, a differential pressure is generated inside and outside the separation tube 42. As a result, the gas contained in the exhaust fluid, here carbon dioxide and gaseous methanol fuel component, is transmitted to the outer space 60 through the gas permeable membrane 46 due to the pressure difference. The liquid in the discharged fluid cannot pass through the gas permeable membrane 46 due to its surface tension, and flows through the flow path as it is. Thereby, gas-liquid separation is performed.

  The exhaust fluid separated by the gas-liquid separator 40 as described above is sent to the mixing tank 30 through the anode channel 22, and the separated gas is sent to the harmful substance removal filter 56 together with the outside air. Here, after impurities and the like are removed, they are sent to the cathode 36 of the cell stack 12.

  As shown in FIG. 1, the fuel cell device 10 includes a temperature control unit 62 that controls the temperature difference between the gas-liquid two-phase flow flowing into the gas-liquid separator 40 and the gas-liquid separator to a predetermined value or less. Yes. The temperature control unit 62 includes a first temperature sensor 64 that detects the temperature of the gas-liquid two-phase flow flowing into the gas-liquid separator 40, a second temperature sensor 66 that detects the temperature of the gas-liquid separator, and a first temperature. A cooling unit that cools the gas-liquid two-phase flow discharged from the anode 37 in accordance with the temperature detected by the sensor and the second temperature sensor. The cooling unit includes a cooling fan 68 that cools the anode side of the cell stack 12.

  The first and second temperature sensors 64 and 66 are each connected to the battery control unit 51 and input the detected temperature to the battery control unit. The operation of the cooling fan 68 is controlled by the battery control unit 51 according to the temperatures detected by the first temperature sensor and the second temperature sensor.

  FIG. 5 shows that the amount of water vapor discharged from the separation tube 42 at each anode circulating liquid temperature (35 to 55 ° C.) in the gas-liquid separator 40 and the flow rate of air passing through the gas-liquid separator are 1.2, 1.41 /. It is the graph which showed the amount of water content in the case of setting it as min. In FIG. 5, RH indicates relative humidity. In addition, the initial temperature of the incoming air is assumed to be 25 ° C.

  The amount of water vapor discharged increases as the temperature of the circulating anode fluid increases, and the amount of water that can be contained increases as the temperature of the gas-liquid separator 40 increases. Therefore, in order to suppress dew condensation on the outer surface of the separation tube 42, it is necessary to prevent a rapid increase in temperature of the circulating anode fluid and a decrease in the gas-liquid separator temperature so that the temperature difference does not increase.

  In the fuel cell device 10, the anode circulating fluid temperature rapidly rises from around the ambient temperature to around 50 to 70 ° C. (depending on the characteristics of the cell stack used) when the device starts up. The temperature of the liquid separator 40 gradually rises due to heat exchange between the circulating anode fluid passing through the separation tube 42 and air passing through the gas-liquid separator 40. For this reason, a difference occurs between the temperatures of the anode circulating liquid and the gas-liquid separator 40 and condensation occurs. Therefore, the occurrence of condensation can be prevented by setting the temperature difference between the anode circulating liquid and the gas-liquid separator 40 to a predetermined value or less, for example, 10 ° C. or less. As a method of making the temperature difference equal to or less than a predetermined value, for example, by cooling the anode circulating liquid to moderate the temperature increase of the anode circulating liquid, it is possible to suppress the occurrence of condensation. Therefore, it is possible to prevent the pores of the gas permeable membrane 46 from being clogged with condensed water, and to suppress a decrease in gas permeability of the gas permeable membrane, that is, gas-liquid separation efficiency.

  According to the present embodiment, the battery control unit 51 determines a predetermined value of the temperature difference necessary for preventing condensation based on the amount of water vapor passing through the separation tube 42 and the air flow rate passing through the gas-liquid separator 40. calculate. Then, the battery control unit 51 detects the circulating anode fluid detected by the first temperature sensor 64, that is, the temperature of the gas-liquid two-phase flow discharged from the cell stack 12, and the gas-liquid detected by the second temperature sensor 66. From the temperature of the separator 40, these temperature differences are compared with a predetermined value, for example, 10 ° C. When the detected temperature difference exceeds the predetermined value range, the battery control unit 51 operates the cooling fan 68 to cool the anode circulating liquid, and the temperature difference falls within the predetermined value range. Control to be.

  The temperature of the anode circulating liquid and the gas-liquid separator 40 is preferably measured by attaching a temperature sensor directly in the flow path through which the anode circulating liquid flows or inside the gas-liquid separator (gas phase part). However, in consideration of the durability problem of the temperature sensor and the like, a temperature sensor is provided on the surface of the pipe forming the flow path, and the temperature of the portion showing the temperature close to those temperatures is measured.

  Regarding the anode circulating fluid temperature, a temperature close to the anode circulating fluid temperature flowing into the gas-liquid separator 40 is measured by measuring the temperature on the section from when the anode circulating fluid is cooled until it flows into the gas-liquid separator. It can be measured. In the system for cooling the cell stack 12 as in the present embodiment, the cell stack temperature and the temperature on the flow path between the cell stack and the gas-liquid separator 40 correspond to each other. For example, the first temperature sensor 64 is provided in the anode flow path 22 between the cooling unit and the gas-liquid separator 40.

  Regarding the temperature of the gas-liquid separator 40, the temperature close to the temperature inside the gas-liquid separator is measured by measuring the temperature on the gas-liquid separator or the flow path of the air that has passed through the gas-liquid separator. Can do. However, when heat generating parts such as the cell stack 12 and the harmful substance removal filter 56 are installed in the rear stage of the gas-liquid separator 40, in order to avoid the influence of the parts on the flow path before the air flows into those parts. Measure the temperature. In this embodiment, the 2nd temperature sensor 66 is provided in the position which detects the temperature of at least one of the gas-liquid separator 40 and the air which passed the gas-liquid separator. For example, the second temperature sensor 66 is provided in the cathode flow path 24 between the outflow side of the gas-liquid separator 40 and the harmful substance removal filter 56.

  When the fuel cell device 10 configured as described above is used as a power source, the fuel pump 28, the liquid supply pump 34, and the air supply pump 52 are operated under the control of the battery control unit 51, and the on-off valves 26, 53, 55 is released. Methanol is supplied from the fuel tank 14 to the mixing tank 30 by the fuel pump 28 and mixed with water in the mixing tank to form a methanol aqueous solution having a desired concentration. Further, the aqueous methanol solution in the mixing tank is supplied to the anode 37 of the cell stack 12 through the anode flow path 22 by the liquid feed pump 34.

  On the other hand, outside air, that is, air is sucked into the cathode channel from the upstream end 24 a of the cathode channel 24 by the air supply pump 52. This air passes through the air filter 50, where dust and impurities in the air are removed. After passing through the air filter 50, the air is sent to the space 60 of the gas-liquid separator 40 through the cathode flow path 24, and further supplied to the cathode 36 of the cell stack 12 through the harmful substance removal filter 56.

  Methanol and air supplied to the cell stack 12 undergo an electrochemical reaction at the electrolyte membrane 144 provided between the anode 37 and the cathode 36, thereby generating electric power between the anode 37 and the cathode 36. The electric power generated in the cell stack 12 is supplied to an electronic device or the like via the battery control unit 51.

  Along with the electrochemical reaction, carbon dioxide is generated on the anode 37 side and water is generated on the cathode 36 side as reaction products in the cell stack 12. The carbon dioxide produced on the anode 37 side and the unreacted methanol aqueous solution that has not been subjected to the chemical reaction are sent to the gas-liquid separator 40 through the anode flow path 22 where they are separated into carbon dioxide and methanol aqueous solution. The separated methanol aqueous solution is recovered from the gas-liquid separator 40 to the mixing tank 30 through the anode flow path 22 and used again for power generation.

  Further, the battery control unit 51 detects the temperature difference between the temperature of the gas-liquid two-phase flow detected by the first temperature sensor 64 and the temperature of the gas-liquid separator 40 detected by the second temperature sensor 66. Then, the anode circulating liquid is cooled by operating the cooling fan 68 so that the temperature difference falls within a predetermined value range, for example, within a temperature difference range of 10 ° C.

  The separated carbon dioxide is sent from the space 60 of the gas-liquid separator 40 to the cathode flow path 24 and further sent to the harmful substance removal filter 56 together with air. After impurities and harmful substances in the air are removed by the harmful substance removal filter 56, air and carbon dioxide are supplied to the cell stack 12 and used for power generation. Impurities in the air can be prevented from being sent to the cell stack 12, and a decrease in power generation efficiency due to these impurities can be prevented.

  Most of the water generated on the cathode 36 side of the cell stack 12 becomes water vapor and is discharged to the cathode flow path 24 together with air. The discharged air and water vapor are sent to the exhaust filter 54, where after dust and impurities are removed, they are exhausted from the downstream end 24b of the cathode channel 24 to the outside.

  According to the fuel cell device 10 configured as described above, by setting the temperature difference between the gas-liquid two-phase flow flowing into the gas-liquid separator 40 and the gas-liquid separator to 10 ° C. or less, for example, It is possible to prevent the occurrence of condensation on the outer surface of the separation tube 42 in the separator. As a result, the pores of the gas permeable membrane 46 are prevented from being blocked by condensed water, and the gas permeability of the gas permeable membrane, that is, the reduction of the gas-liquid separation efficiency in the gas-liquid separator 40 is suppressed. Can do. Therefore, it is possible to efficiently separate the gas in the liquid and obtain a fuel cell device with improved power generation efficiency.

Next explained is a fuel cell apparatus according to the second embodiment of the invention.
As shown in FIG. 6, according to the second embodiment, the temperature control unit 62 of the fuel cell device is opposed to the heat exchanger 70 provided in the anode flow path 22 and the heat exchanger as a cooling unit. The cooling fan 72 is provided. The heat exchanger 70 is configured by fins or the like, and is provided in the anode flow path 22 between the anode outflow side of the cell stack 12 and the gas-liquid separator 40. In addition, the temperature control unit 62 includes a heater 74 that heats the gas-liquid separator 40, that is, heats the air in the space 60. For example, the heater 74 is provided adjacent to and opposed to the outer surface of the container 44 of the gas-liquid separator 40.

The temperature control unit 62 includes a first temperature sensor 64 that detects the temperature of the gas-liquid two-phase flow that flows into the gas-liquid separator 40, and a second temperature sensor 66 that detects the temperature of the gas-liquid separator. Yes. The first temperature sensor 64 is provided in the anode flow path 22 between the heat exchanger 70 and the gas-liquid separator 40. The second temperature sensor 66 is provided at a position for detecting the temperature of at least one of the gas-liquid separator 40 and the air that has passed through the gas-liquid separator. For example, the second temperature sensor 66 is provided in the cathode flow path 24 between the outflow side of the gas-liquid separator 40 and the harmful substance removal filter 56. The first and second temperature sensors 64 and 66 are each connected to the battery control unit 51 and input the detected temperature to the battery control unit. The operation of the cooling fan 72 and the heater 74 is controlled by the battery control unit 51 in accordance with the temperatures detected by the first temperature sensor and the second temperature sensor.
In the second embodiment, other configurations are the same as those of the first embodiment described above, and the same reference numerals are given to the same portions, and detailed descriptions thereof are omitted.

  According to the fuel cell apparatus having the above configuration, the battery control unit 51 detects the anode circulating liquid detected by the first temperature sensor 64, that is, the temperature of the gas-liquid two-phase flow discharged from the cell stack 12, and the second temperature. From the temperature of the gas-liquid separator 40 detected by the sensor 66, these temperature differences are compared with a predetermined value, for example, 10 ° C. When the detected temperature difference exceeds the predetermined value range, the battery control unit 51 operates the cooling fan 72 to cool the anode circulating liquid, or operates the heater 74 to operate the gas liquid. The air in the separator 40 is heated, and the temperature is controlled so that the temperature difference falls within a predetermined value range. The temperature control may be performed using only one of the cooling fan 72 and the heater 74, or both may be performed in combination.

  According to the fuel cell device 10 configured as described above, by setting the temperature difference between the gas-liquid two-phase flow flowing into the gas-liquid separator 40 and the gas-liquid separator to 10 ° C. or less, for example, It is possible to prevent the occurrence of condensation on the outer surface of the separation tube 42 in the separator. Thereby, it can prevent that the hole of the gas-permeable film 46 is block | closed with the dew condensation water, and can suppress the fall of the gas-liquid separation efficiency in the gas-liquid separator 40. FIG. Therefore, it is possible to efficiently separate the gas in the liquid and obtain a fuel cell device with improved power generation efficiency.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

  For example, in the gas-liquid separator, the shape of the gas permeable membrane is not limited to a cylindrical shape, but may be a sheet shape or any other shape. The cooling unit for cooling the anode circulating fluid discharged from the cell stack is not limited to the cooling fan and the heat exchanger, and a water-cooled cooler may be used. The form of the fuel cell is not limited to DMFC, but may be other forms such as PEFC (Polymer Electrolyte Fuel Cell).

FIG. 1 is a diagram showing a circulation system of a fuel cell device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a cell stack of the fuel cell device. FIG. 3 is a diagram schematically showing a single cell of the cell stack. FIG. 4 is a sectional view showing a gas-liquid separator in the fuel cell device. FIG. 5 is a diagram showing the relationship between the temperature of the gas-liquid separator, the amount of water vapor discharged, and the water content possible. FIG. 6 is a diagram showing a circulation system of a fuel cell device according to a second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell apparatus, 12 ... Cell stack, 14 ... Fuel tank, 20 ... Circulation system,
22 ... Anode channel, 24 ... Cathode channel, 30 ... Mixing tank,
36 ... Cathode (air electrode), 37 ... Anode (fuel electrode), 40 ... Gas-liquid separator,
42 ... separation tube, 44 ... container, 46 ... gas permeable membrane, 60 ... space,
62 ... Temperature controller, 64 ... First temperature sensor, 66 ... Second temperature sensor, 68 ... Cooling fan 70 ... Heat exchanger, 72 ... Cooling fan, 74 ... Heater

Claims (11)

An electromotive unit comprising a cell having an anode and a cathode, and generating electricity by a chemical reaction;
A fuel tank containing fuel;
A circulation system having a fuel flow path for circulating the fuel supplied from the fuel tank through the anode of the electromotive section, and a gas flow path for supplying air through the cathode of the electromotive section;
A gas-liquid separator that is provided between the outflow end of the electromotive unit and the fuel tank in the fuel flow path and separates liquid and gas. The gas-liquid separator is formed of a porous material and discharged from the anode. A gas permeable membrane having a first surface in contact with the gas-liquid two-phase flow and a second surface in contact with the air supplied from the gas flow path, and transmitting gas in the gas-liquid two-phase flow. A gas-liquid separator;
A temperature control unit for controlling a temperature difference between the gas-liquid two-phase flow flowing into the gas-liquid separator and the gas-liquid separator to a predetermined value or less;
A fuel cell device comprising:   The temperature control unit includes a first temperature detector that detects a temperature of a gas-liquid two-phase flow flowing into the gas-liquid separator, a second temperature detector that detects a temperature of the gas-liquid separator, and the first The fuel cell device according to claim 1, further comprising: a cooling unit that cools the gas-liquid two-phase flow discharged from the anode in accordance with the temperature detected by the first temperature detector and the second temperature detector. .   The fuel cell device according to claim 2, wherein the temperature control unit includes a heater that heats the gas-liquid separator.   The temperature control unit includes a first temperature detector that detects a temperature of a gas-liquid two-phase flow flowing into the gas-liquid separator, a second temperature detector that detects a temperature of the gas-liquid separator, and the first The fuel cell device according to claim 1, further comprising: a heater that heats the gas-liquid separator according to the temperature detected by the first temperature detector and the second temperature detector.   The said temperature control part is provided with the battery control part which calculates the said predetermined value with the amount of water vapor | steam which passes the said gas-permeable membrane, and the air flow rate which passes the said gas-liquid separator. The fuel cell device according to any one of claims.   The fuel cell device according to claim 2, wherein the cooling unit includes a cooling fan that cools an anode side of the cell.   The fuel cell device according to claim 2, wherein the cooling unit includes a heat exchanger that cools the fuel flow path between the cell and the gas-liquid separator.   The fuel cell device according to claim 2 or 4, wherein the first temperature detector is provided in the fuel flow path between the cooling unit and the gas-liquid separator.   5. The fuel cell device according to claim 2, wherein the second temperature detector is provided at a position that detects a temperature of at least one of the gas-liquid separator and the air that has passed through the gas-liquid separator. 6.   2. The gas permeable membrane is formed in a cylindrical shape, the first surface defines a part of a fuel flow path through which the gas-liquid two-phase flow flows, and the second surface forms an outer surface. 10. The fuel cell device according to any one of items 9 to 9.   The fuel cell device according to claim 10, wherein the gas-liquid separator includes an outer container that covers an outer surface of the gas permeable membrane and defines a space that forms a part of the gas flow path.

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