JP2006024541A - Liquid fuel charge method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable to fill a liquid fuel into a fuel container for a fuel cell without mixing air. <P>SOLUTION: Before filling a methanol water solution to be originally filled into a fuel reserve chamber 3 of a fuel cell fuel container 1, pipes 33, 34 are closed and the pipe 32 and the liquid-fuel fuel container 1 are opened, and a methanol water solution F' with higher concentration than the filling methanol water solution is filled temporarily into the fuel reserve chamber 3 by operating a pump P1 and by lowering a barrier rib member 5. Then, the pipes 32, 34 are closed and the pipe 33 and the liquid-fuel fuel container 1 are opened, and the high concentration liquid F' temporarily filled into the fuel reserve chamber 3 is discharged to a tank 30 together with air by the pressure of a compression gas G in the liquid-fuel fuel container 1. Next, the pipes 32, 33 are closed and the pipe 34 and the liquid-fuel fuel container 1 are made open, then the liquid fuel F is injected into the fuel reserve chamber 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of filling a fuel cell such as a direct methanol fuel cell (DMFC) with a liquid fuel such as an aqueous methanol solution.

  A fuel cell is an energy conversion device that generates electricity by reacting hydrogen and oxygen. Its operating temperature is low and it can be expected to reduce the size of the device, so it is currently used in various applications, such as notebook computers and mobile phones. Development is underway in fields such as power supplies for mobile devices that can extend the continuous operation time.

  Fuel cell fuels include natural gas, city gas, coal gas, and other liquids such as methanol and ethanol. The former is exclusively used for household generators that are always supplied with fuel while fixed in the home. Since the latter does not use a large cylinder and can be easily refilled with fuel by an individual, it is used for the above-mentioned power source for mobile devices.

In order to replenish fuel in a fuel cell used for the latter power source for mobile devices, a fuel container (for example, a fuel cartridge) for supplying liquid fuel is required. This fuel cell fuel container is small and light, and it is desirable to omit the auxiliary equipment of the equipment body that uses the fuel cell, particularly the suction pump. Therefore, the fuel container itself that contains the fuel discharges the fuel by itself. A mechanism for supplying is being studied (see, for example, Patent Document 1).
JP 2003-176899 A

  By the way, when filling liquid fuel into a fuel cell fuel container, fuel injection means is connected to the fuel cell fuel container and the fuel cell fuel container valve is opened to inject liquid fuel. There is a problem that a slight amount of air near the valve is mixed into the fuel container for the fuel cell.

  The mixed air adheres to the inner wall surface of the fuel container for the fuel cell and the piston-like partition wall member that partitions the liquid fuel and the compressed gas, and eventually the air dissolves in the liquid fuel, and the oxygen contained in the air becomes methanol. Oxidize liquid fuel such as formaldehyde and formic acid to alter the liquid fuel, or propagate germs on the liquid fuel to make long-term storage of the liquid fuel difficult.

  In the past, the vacuum filling method was used to suppress the mixing of air, but the degree of vacuum at this time is strictly about 0.5 atm, and the mixing of air cannot be completely prevented. It is not sufficient to suppress the deterioration of liquid fuel and the propagation of germs.

  Air bubbles adhere to the inner wall surface of the fuel cell fuel container and the piston-shaped partition member because these materials are coated with polypropylene (PP), polytetrafluoroethylene (PTFE), or PTFE, This is due to the fact that the surface energy with respect to is large, that is, the wettability is poor. In order to improve such wettability, surface treatment by applying chemicals is generally considered. However, this method is not preferable because impurities are mixed into the liquid fuel and the cells of the fuel cell are deteriorated. In addition, it is possible to improve the wettability by forming radicals on the piston-shaped partition wall member or the inner wall surface of the fuel container by oxygen plasma irradiation. However, it is physically possible to perform oxygen plasma irradiation on the inner wall surface of the fuel container. Impossible.

  The present invention has been made in view of these points, and an object of the present invention is to provide a method of filling liquid fuel that does not mix air when filling a fuel cell fuel container with liquid fuel. It is.

  The liquid fuel filling method of the present invention is a method of filling a fuel cell fuel container containing liquid fuel for a fuel cell with the liquid fuel before filling the fuel cell fuel container with the liquid fuel. Supplying a liquid having a higher concentration than the liquid fuel of the same type as the liquid fuel to the fuel container for the fuel cell; then, discarding the supplied high-concentration liquid; It is characterized by filling with liquid fuel.

  For example, if the liquid fuel to be filled is methanol or a methanol aqueous solution, the liquid having a higher concentration than the liquid fuel of the same type as the liquid fuel to be filled is a methanol aqueous solution having a higher concentration than the methanol aqueous solution to be filled. If the liquid fuel to be filled is ethanol or an ethanol aqueous solution, it means an ethanol aqueous solution having a higher concentration than that of the ethanol aqueous solution to be filled, and the type is the same liquid only with a high concentration.

  After supplying a liquid having a higher concentration than the liquid fuel of the same type as the liquid fuel to be filled to the fuel cell fuel container, the high concentration liquid is caused to flow in the fuel cell fuel container, and thereafter It is more preferable to discard the supplied high-concentration liquid.

  When the liquid fuel is methanol or a methanol aqueous solution, the high-concentration liquid is a methanol aqueous solution of 50% by weight or more, and further a methanol aqueous solution of 70% by weight or more, depending on the concentration of the liquid fuel to be filled. It is preferable. Further, when the liquid fuel is ethanol or an ethanol aqueous solution, the high concentration liquid fuel is 50% by weight or more ethanol solution, and further 70% by weight or more ethanol, depending on the concentration of the liquid fuel to be filled. An aqueous solution is preferred. When the liquid fuel is 100% methanol or ethanol, the high concentration liquid is 100% methanol or ethanol.

  In the liquid fuel filling method of the present invention, before the liquid fuel is filled into the fuel cell fuel container, a liquid having a higher concentration than the liquid fuel of the same type as the liquid fuel to be filled is supplied to the fuel cell fuel container. Then, the supplied high-concentration liquid is discarded, and then the liquid fuel is filled in the fuel cell fuel container. Therefore, when the liquid fuel is filled in the fuel cell fuel container, the fuel cell fuel container near the valve Liquid fuel can be filled without mixing air.

  That is, by supplying a liquid having a higher concentration than the liquid fuel of the same type as that of the liquid fuel to be filled to the fuel cell fuel container, the wettability of the inner wall surface of the fuel cell fuel container and the piston-shaped partition wall member is improved. In order to improve, air bubbles are prevented from sticking to the inner wall surface of the fuel cell fuel container or the piston-like partition wall, and the air in the vicinity of the valve is replaced with high-concentration liquid and discarded together with high-concentration liquid. Therefore, liquid fuel can be filled without mixing air into the fuel cell fuel container.

  As a result, the deterioration of the liquid fuel can be suppressed, and the liquid fuel can be stored for a long time without breeding germs.

  A method for filling a fuel container for a fuel cell containing the liquid fuel for the fuel cell of the present invention with the liquid fuel will be described below with reference to the drawings. FIG. 1 is a front sectional view of the center of the fuel cell fuel container, and FIG. 2 is an enlarged sectional view of the closed valve portion of FIG.

  The fuel cell fuel container 1 of the embodiment of FIG. 1 is for containing a liquid fuel F for a fuel cell such as a methanol aqueous solution or an ethanol aqueous solution having a predetermined concentration, and for supplying the liquid fuel F to the fuel cell. It is attached to a fuel cell body (not shown).

  Here, methanol aqueous solution or ethanol aqueous solution means a mixture of methanol and pure water, ethanol and pure water, and pure water is water that can be regarded as almost the same as pure water excluding impurities as much as possible, It is meant to include purified water as well as pure water as a chemical species. For the sake of simplification, hereinafter, the term “aqueous methanol solution” means that 100% methanol is included, and the term “ethanol aqueous solution” means that it contains 100% ethanol.

  The fuel container 1 includes a container body 2 having an opening on the outer surface and a connection portion 24 for supplying liquid fuel F, and liquid fuel F formed inside the container body 2 and supplied to a fuel cell (not shown). A fuel storage chamber 3 to be accommodated and an air chamber 4 which is formed inside the container body 2 and which communicates with the fuel storage chamber 3 at the end and encloses a compressed gas G that generates stress for pushing out the liquid fuel F. A piston-like partition member 5 that is movably disposed in the fuel storage chamber 3 and partitions the liquid fuel F and the compressed gas G, and a valve 7 that cuts off communication between the fuel storage chamber 3 and the connecting portion 24. The elastic body 8 is disposed at the bottom of the container body 2 and is fixed to the support member 52 incorporated in the partition member 5 that has moved downward.

  The container body 2 is formed by resin molding, and is disposed in a double structure inside the outer container 21, an outer container 21 that forms an outer shape, a lid 22 that seals the upper opening of the outer container 21, and the outer container 21. It is comprised with the inner container 23, the connection part 24 is formed in the center of the cover body 22, and the valve | bulb 7 is installed.

  The inner container 23 is cylindrical, and the lower end portion is not joined to the bottom surface of the outer container 21, and a communication passage 25 is formed to communicate the inside of the inner container 23 with the inside of the outer container 21. The bottom of the air chamber 4 and the bottom of the air chamber 4 can communicate with each other at the end.

  In addition, a through hole 23 a is opened at the center of the upper end of the inner container 23, the fuel storage chamber 3 communicates with the connection portion 24 via the valve 7, and the liquid fuel F flows according to the communication cutoff operation of the valve 7. Emission supply can be performed. Details of the valve 7 will be described later with reference to FIG.

  A cylindrical wall 23b (see FIG. 2) extending upward is provided on the upper surface of the upper end portion of the inner container 23, and a lower end mounting cylindrical portion 71a of the housing 71 of the valve 7 is fitted and mounted in the cylindrical wall 23b. Is held.

  The lower end portion of the inner container 23 is opened without being joined to the bottom surface of the outer container 21, and the piston-like partition member 5 slidably fitted into the inner container 23 is separated by upper and lower seal portions 5 a and 5 b on the outer periphery. The cylinder-shaped inner container 23 is in airtight contact with the inner wall of the cylinder-like inner container 23, moves up and down in a stable posture, and the liquid fuel F is sealed in the fuel storage chamber 3 in the upper space. The partition member 5 functions as a moving partition partitioning the liquid fuel F stored in the fuel storage chamber 3 and the compressed gas G stored in the air chamber 4, and is caused by the pressure of the compressed gas G acting on the back surface of the partition member 5. When the liquid fuel F on the front surface is pressurized and the valve 7 communicates, the liquid fuel F is pushed out from the connecting portion 24.

  The position of the partition member 5 changes according to the storage volume of the liquid fuel F remaining in the fuel storage chamber 3, and the volume of the compressed gas G changes and the pressure changes accordingly. A pressure for moving the partition member 5 is secured so that the partition member 5 can be pushed out until the amount disappears.

  Further, the surface of the seal portions 5a and 5b of the partition wall member 5 or the inner wall surface of the inner container 23, and both, PTFE (polytetrafluoroethylene) coating that is non-eluting with respect to the liquid fuel F, or DLC A low friction coefficient coating such as a (diamond-like carbon) coating is applied to reduce the movement resistance of the partition member 5 and ensure a reliable and good operation even when the pressure of the compressed gas G is low.

  Here, an example of the mechanism of the valve 7 will be described. As shown in an enlarged view in FIG. 2, the valve 7 includes a housing 71 as a fixing member to the lid body 22, a stem 72 that moves according to the connection with the fuel cell, a spring 73 that biases the stem 72 in the closing direction, A valve body 74 (O-ring) for opening and closing the supply of fuel is formed, and these are preferably formed of a non-metallic material.

  The housing 71 is formed in a cylindrical shape, and includes a mounting cylinder portion 71a extended to the lower end portion and an annular protrusion 71b protruding inside. The stem 72 is formed in a rod shape, and includes a head portion 72a spreading outward at the upper end and a shaft portion 72b below the head portion 72a. A stem 72 is inserted into the housing 71 so as to be movable in the axial direction, and a spring 73 is interposed between the lower surface of the head 72a and the upper surface of the annular projection 71b, and the stem 72 is biased upward. Yes. The distal end of the stem 72b of the stem 72 protrudes through the inner hole of the annular protrusion 71b, and the valve body 74 by an O-ring attached to the outer periphery of the distal end of the axle 72b presses against the lower end of the annular protrusion 71b. The inner hole is closed to open and close the fuel supply.

  The housing 71 is assembled to the boss portion 24a with respect to the connecting portion 24 of the container body 2 via a sealing O-ring 76 attached to the outer periphery of the lower portion thereof. The mounting cylinder portion 71a of the housing 71 protrudes from the boss portion 24a into the outer container 21, and the upper cylinder wall 23b of the inner container 23 is fitted into the mounting cylinder portion 71a as described above to hold the inner container 23. Therefore, the sealing material 75 (O-ring) mounted on the outer periphery of the mounting cylinder 71a is sealed between the two, and the communication path through which the compressed gas in the air chamber 4 flows into the fuel storage chamber 3 is blocked. .

  Further, when the head 72a of the stem 72 is pushed against the spring 73 from the outside, the valve body 74 at the tip of the stem 72 is separated from the annular protrusion 71b and the inner hole is opened, and the shaft portion 72b and the annular protrusion 71b are opened. The liquid fuel F in the fuel storage chamber 3 is jetted and supplied through the gap between the head 72 a and the housing 71.

  Further, the valve 7 is configured such that the valve body 74 is made of an elastic material using an O-ring, and the elastic material is regulated by a circumferential groove of the shaft portion 72b so as not to swell and deform in the valve opening / closing direction (axial direction). Even if the valve body 74 (elastic material) in contact with the liquid fuel F expands due to swelling or the like, the volume change is regulated in a direction perpendicular to the valve opening / closing movement direction. Is suppressed.

  From the viewpoint of preventing oxygen that adversely affects the reaction in the fuel cell from being mixed into the liquid fuel F, and further from preventing the liquid fuel F from being oxidized, A gas that does not contain oxygen, such as nitrogen, carbon dioxide, or deoxygenated air, is selected.

  Next, the sealing of the compressed gas G into the air chamber 4 will be described with reference to FIG. The compressed gas G is sealed before the liquid fuel F is injected into the fuel storage chamber 3 and before the high-concentration liquid F ′ described later is supplied.

  As the compressed gas G is injected into the fuel storage chamber 3 through the valve 7, the partition member 5 descends, and the elastic body 8 comes into contact with the bottom surface of the support member 52 at the position shown in FIG. As the compressed gas G is injected into the fuel storage chamber 3 through 7, the partition wall member 5 descends, and the upper and lower sides of the partition wall member 5 are brought into a communication state by the communication passage 25, and the compressed gas is transferred from the fuel storage chamber 3 to the air chamber 4 Inject. And when the inside of the air chamber 4 reaches a predetermined pressure, the injection of the compressed gas is stopped, and then the valve 7 which is closed is opened to discharge the compressed gas in the fuel storage chamber 3.

  In response to this, the partition member 5 rises due to the repulsive force of the elastic body 8 and returns to the sealed state of the fuel storage chamber 3, and further gas discharge causes the partition member 5 to have the pressure of the compressed gas in the air chamber 4 on its back. The gas chamber 4 is enclosed in the air chamber 4 by moving up to the upper end of the inner container 23 in an acted state and discharging all the gas in the fuel storage chamber 3.

  Next, a method of filling the fuel storage chamber 3 with the liquid fuel F will be described with reference to FIG. FIG. 3 is a schematic view showing one embodiment of filling a fuel container for a fuel cell with fuel. In the liquid fuel filling method of the present invention, before the fuel storage chamber 3 is filled with the liquid fuel F, the fuel storage chamber 3 is supplied with a liquid F ′ having a higher concentration than the liquid fuel of the same type as the liquid fuel F to be filled. Then, the supplied high-concentration liquid F ′ is discarded, and then the liquid fuel F originally filled in the fuel storage chamber 3 is filled.

  The liquid fuel F is a methanol aqueous solution or an ethanol aqueous solution, and the high concentration liquid F ′ is a methanol aqueous solution having a concentration higher than that of the methanol aqueous solution if the liquid fuel F to be originally filled is a methanol aqueous solution. If the liquid fuel F is an ethanol aqueous solution, the ethanol aqueous solution has a higher concentration than the ethanol aqueous solution.

  As shown in FIG. 3A, a cock Q is connected to the connecting portion 24 of the fuel container 1 for liquid fuel, and two pipes 32 and 33 further connected to the tank 30 are connected to the cock Q. A pipe 34 connected to 31 is connected, and the cock Q is configured to be able to change the direction of liquid flow with respect to the pipes 32, 33, 34 and the liquid fuel fuel container 1. The pipe 32 and the pipe 34 are respectively provided with a pump P1 and a pump P2 that suck up the liquid fuel F or F ′. The tank 30 stores a liquid F ′ having a concentration higher than that of the liquid fuel F originally filled in the fuel storage chamber 3, while the tank 31 stores the liquid fuel originally filled in the fuel storage chamber 3. F is accommodated.

  First, the cock Q is moved so that the pipe 33 and the pipe 34 are closed, the pipe 32 and the liquid fuel fuel container 1 are opened, and then the pump P1 is operated. The liquid F ′ flows in the direction of the arrow in FIG. 3A, and the high-concentration liquid F ′ that has entered the fuel storage chamber 3 in the fuel container 1 for liquid fuel lowers the partition member 5 and moves to the fuel storage chamber. 3 is temporarily filled.

  Subsequently, when the cock Q is moved to close the pipe 32 and the pipe 34 and the pipe 33 and the liquid fuel fuel container 1 are opened, the pressure of the compressed gas G in the liquid fuel fuel container 1 is increased. The high-concentration liquid F ′ temporarily filled in the fuel storage chamber 3 flows in the direction of the arrow shown in FIG. 3B and is discharged to the tank 30 together with air. As a result, air is not present in the slight gap of the inner container 23 and is filled with the high-concentration liquid F ′. By repeating this operation several times, the air (bubbles) adhering to the inner wall surface of the inner container 23 and the partition wall member 5 due to the slight air existing in the vicinity of the valve 7 becomes the high-concentration liquid F ′. The air bubbles can be discharged into the tank 30 by being separated by the flow of.

  Next, after the cock Q is moved so that the pipe 32 and the pipe 33 are closed and the pipe 34 and the liquid fuel fuel container 1 are opened, the liquid fuel F in the tank 31 is operated when the pump P2 is operated. Flows in the direction of the arrow in FIG. 3 (c), and the liquid fuel F is injected into the fuel storage chamber 3 while lowering the partition member 5. In this way, the fuel cell fuel container 1 containing the liquid fuel F so as to be ejected is completed.

  Here, the case where the liquid fuel F in the tank 31 is injected into the fuel storage chamber 3 after the high concentration liquid F ′ is discharged into the tank 30 has been described. However, the high concentration liquid F ′ is caused to flow. After the bubbles are discharged together with the high-concentration liquid F ′ to the tank 30, the high-concentration liquid F ′ in the tank 30 may be refilled in the fuel storage chamber 3 to complete the fuel container 1 for the fuel cell. .

FIG. 4 is a schematic view showing another embodiment in which fuel is filled in a fuel container for a fuel cell. In this embodiment, the high-concentration liquid F ′ temporarily filled in the fuel storage chamber 3 is discharged. The tank 35 is provided separately from the tank 31 containing the high-concentration liquid F ′ (others have the same structure as in FIG. 3, and the same components as in FIG. 3 are assigned the same reference numerals in FIG. In the following, the description is omitted). The high-concentration liquid F ′ temporarily filled in the fuel storage chamber 3 may be mixed with foreign substances in addition to bubbles. In this way, the high-concentration liquid F ′ temporarily filled is provided separately. By discharging to the tank 35, it is possible to prevent the foreign matter from being temporarily filled in the fuel storage chamber 3 again.
Next, an embodiment of the liquid fuel filling method of the present invention will be shown.

Example 1
A tank 30 shown in FIG. 3 contains a 100 wt% methanol aqueous solution (hereinafter, the methanol aqueous solution supplied before filling the fuel container with liquid fuel is referred to as a temporarily filled methanol aqueous solution). 5 ml of a 10 wt% aqueous methanol solution containing 10 wt% and distilled water 90 wt% was accommodated.

  The cock Q is moved so that the pipe 33 and the pipe 34 are closed, and the pipe 32 and the liquid fuel fuel container 1 are opened. Then, the pump P1 is operated, and the fuel storage chamber 3 is filled with the high-concentration liquid F. ′ Was temporarily filled. Subsequently, the cock Q is moved so that the pipe 32 and the pipe 34 are closed, the pipe 33 and the liquid fuel fuel container 1 are opened, and the high concentration liquid temporarily filled in the fuel storage chamber 3 is obtained. F ′ was discharged. Next, the cock Q is moved so that the pipe 32 and the pipe 33 are closed, and the pipe 34 and the liquid fuel fuel container 1 are opened, and then the pump P2 is operated to bring the fuel storage chamber 3 to 10 weight. % Methanol aqueous solution was injected. After the injection, the height h from the floor surface on which the fuel cell fuel container 1 was placed to the bottom surface of the support member 52 was measured with a height gauge. The operation so far was performed once, and the average value of the height h was repeated 30 times.

  Subsequently, the height h was determined in the same manner as above except that the temporarily filled methanol aqueous solution was changed to an 80 wt% methanol aqueous solution, a 60 wt% methanol aqueous solution, a 40 wt% methanol aqueous solution, and a 20 wt% methanol aqueous solution. The results are shown in FIG.

  FIG. 5 is a graph showing the relationship between the concentration of the temporarily filled methanol aqueous solution and the bubbles in the fuel cell fuel container after the 10 wt% methanol aqueous solution is filled when the fuel cell fuel container is filled with the 10 wt% methanol aqueous solution. It is. According to this, when the fuel container for a fuel cell is filled with a 10 wt% aqueous methanol solution, the height h remains about 17.6 mm until the concentration of the temporarily filled aqueous methanol solution is about 70 wt%, Until this time, no bubbles were observed in the fuel storage chamber 3. As the concentration of the temporarily filled methanol aqueous solution decreases, the height h gradually decreases. That is, as the concentration of the temporarily filled methanol aqueous solution decreases, the number of bubbles in the fuel storage chamber 3 increases, so that the partition member 5 approaches the floor surface. The height h has become smaller.

  As is clear from the graph shown in FIG. 5, when the 10% by weight aqueous methanol solution is filled, if the aqueous methanol solution having a concentration higher than 50% by weight is temporarily filled, bubbles are not formed at all. When a 70% by weight or more methanol aqueous solution was temporarily filled, a 10% by weight methanol aqueous solution could be filled without mixing air.

(Example 2)
In the tank 30 shown in FIG. 3, a 100 wt% methanol aqueous solution was accommodated as a temporarily filled methanol aqueous solution, and in the tank 31, 5 ml of a 20 wt% methanol aqueous solution of 20 wt% methanol and 80 wt% distilled water was accommodated. A 20 wt% aqueous methanol solution was injected into the fuel storage chamber 3 in the same procedure as in Example 1. After the injection, the bubbles adhering in the fuel storage chamber 3 were collected near the valve 3, the bubbles were collected in a beaker which was opened and inverted in a prepared water tank, and the volume was measured by sucking the bubbles with a syringe. . Subsequently, the temporarily filled methanol aqueous solution was changed to an 80 wt% methanol aqueous solution, a 60 wt% methanol aqueous solution, a 40 wt% methanol aqueous solution, and a 20 wt% methanol aqueous solution, and the bubble volume in each case was measured. The results are shown in FIG.

  FIG. 6 is a graph showing the relationship between the concentration of the temporarily filled methanol aqueous solution and the bubbles in the fuel cell fuel container after filling the 20 wt% methanol aqueous solution when the fuel cell fuel container is filled with the 10 wt% methanol aqueous solution. It is. According to this, when the fuel container for fuel cell is filled with 20% by weight methanol aqueous solution, the bubble volume is zero until the concentration of the temporarily filled methanol aqueous solution is about 70% by weight. No bubbles were found in the storage chamber 3. The bubble volume gradually increased as the concentration of the temporarily filled methanol aqueous solution decreased.

  As is clear from the graph shown in FIG. 6, when 20% by weight aqueous methanol solution is filled, if the 50% by weight methanol aqueous solution is temporarily filled, bubbles are reduced compared to the case where no temporary filling is performed. When a methanol aqueous solution of 70% by weight or more was temporarily filled, a 20% by weight methanol aqueous solution could be filled without mixing air.

Example 3
In Example 2, the experiment was performed in the same manner as in Example 2 except that the methanol aqueous solution housed in the tank 31 was changed to 30% by weight methanol and 70% by weight distilled water. The results are shown in FIG.

  FIG. 7 is a graph showing the relationship between the concentration of the temporarily filled methanol aqueous solution and the bubbles in the fuel cell fuel container after filling the 30 wt% methanol aqueous solution when the fuel cell fuel container is filled with the 30 wt% methanol aqueous solution. It is. According to this, when the fuel container for fuel cell is filled with 30% by weight methanol aqueous solution, the bubble volume is zero until the concentration of the temporarily filled methanol aqueous solution is about 70% by weight. No bubbles were found in the storage chamber 3. The bubble volume gradually increased as the concentration of the temporarily filled methanol aqueous solution decreased. Since the concentration of the temporarily filled methanol aqueous solution is higher than the concentration of the methanol aqueous solution to be filled, an experiment was not performed with a concentration of the temporarily filled methanol aqueous solution lower than 30% by weight. Assuming that the bubbles in the fuel storage chamber 3 increase as the concentration of the temporarily filled ethanol aqueous solution decreases.

  As is clear from the graph shown in FIG. 7, when 30% by weight methanol aqueous solution is filled, if 50% by weight or more methanol aqueous solution is temporarily filled, bubbles are reduced compared to the case where no temporary filling is performed. If a 70% by weight or more methanol aqueous solution was temporarily filled, it was possible to fill the 30% by weight methanol aqueous solution without mixing air.

Example 4
In Example 2, an experiment was performed in the same manner as in Example 2 except that the methanol aqueous solution housed in the tank 31 was changed to a 50 wt% methanol aqueous solution of 50 wt% methanol and 50 wt% distilled water. The results are shown in FIG.

  FIG. 8 is a graph showing the relationship between the concentration of the temporarily filled methanol aqueous solution and the bubbles in the fuel cell fuel container after filling the 50 wt% aqueous methanol solution when the fuel cell fuel container is filled with the 50 wt% methanol aqueous solution. It is. According to this, when the fuel container for a fuel cell is filled with 50% by weight methanol aqueous solution, the bubble volume is zero until the concentration of the temporarily filled methanol aqueous solution is about 70% by weight. No bubbles were found in the storage chamber 3. The bubble volume gradually increased as the concentration of the temporarily filled methanol aqueous solution decreased. Since the concentration of the temporarily filled methanol aqueous solution is higher than the concentration of the methanol aqueous solution to be filled, the experiment was not performed with the concentration of the temporarily filled methanol aqueous solution lower than 50% by weight. Assuming that the bubbles in the fuel storage chamber 3 increase as the concentration of the temporarily filled methanol aqueous solution decreases.

  As is apparent from the graph shown in FIG. 8, when 50% by weight methanol aqueous solution is filled, if the methanol aqueous solution having a concentration higher than 50% by weight is temporarily filled, bubbles are not formed at all. It was possible to reduce the amount of methanol aqueous solution by 70% by weight or more, and 50% by weight methanol aqueous solution could be filled without air mixing.

(Example 5)
In Example 2, a 100 wt% ethanol aqueous solution (hereinafter referred to as an ethanol aqueous solution supplied before filling the fuel container with liquid fuel) is accommodated in the tank 30, and the ethanol is stored in the tank 31. A 10 wt% ethanol aqueous solution containing 10 wt% and distilled water 90 wt% was contained, and the bubble volume was measured in the same manner as in Example 2. Subsequently, the temporarily filled methanol aqueous solution was changed to an 80 wt% ethanol aqueous solution, a 60 wt% ethanol aqueous solution, a 40 wt% ethanol aqueous solution, and a 20 wt% ethanol aqueous solution, and the bubble volume in each case was measured. The results are shown in FIG.

  FIG. 9 is a graph showing the relationship between the concentration of the temporarily filled ethanol aqueous solution and the bubbles in the fuel cell fuel container after the 10 wt% ethanol aqueous solution is filled when the fuel cell fuel container is filled with the 10 wt% ethanol aqueous solution. It is. According to this, when a 10 wt% ethanol aqueous solution is filled in a fuel cell fuel container, the bubble volume is zero until the concentration of the temporarily filled ethanol aqueous solution is about 70 wt%. No bubbles were found in the storage chamber 3. As the concentration of the temporarily filled ethanol aqueous solution decreases, the bubble volume gradually increases. When the concentration of the temporarily filled ethanol aqueous solution is lower than 40% by weight, the bubble volume in the fuel storage chamber 3 becomes substantially constant.

  As is apparent from the graph shown in FIG. 9, when 10% by weight ethanol aqueous solution is filled, if 50% by weight or more ethanol aqueous solution is temporarily filled, bubbles are reduced compared to the case where no temporary filling is performed. If a 70% by weight or more ethanol aqueous solution was temporarily filled, a 10% by weight ethanol aqueous solution could be filled without air mixing.

(Example 6)
In Example 5, an experiment was conducted in the same manner as in Example 5 except that a 30 wt% aqueous ethanol solution containing 30 wt% ethanol and 70 wt% distilled water was contained in the tank 31. The results are shown in FIG.

  FIG. 10 is a graph showing the relationship between the concentration of the temporarily filled ethanol aqueous solution and the bubbles in the fuel cell fuel container after filling the 30 wt% aqueous ethanol solution when the fuel cell fuel vessel is filled with the 30 wt% aqueous ethanol solution. It is. According to this, when a 30 wt% ethanol aqueous solution is filled in a fuel cell fuel container, the bubble volume is zero until the concentration of the temporarily filled ethanol aqueous solution is about 70 wt%. No bubbles were found in the storage chamber 3. The bubble volume gradually increased as the concentration of the temporarily filled ethanol aqueous solution decreased. Since the concentration of the temporarily filled ethanol aqueous solution is higher than the concentration of the ethanol aqueous solution to be filled, no experiment was conducted at a concentration of the temporarily filled ethanol aqueous solution lower than 30% by weight. Assuming that the bubble volume in the fuel storage chamber 3 is constant when the concentration of the temporarily filled ethanol aqueous solution is lower than 30% by weight.

  As is apparent from the graph shown in FIG. 10, when 30% by weight ethanol aqueous solution is filled, if the 55% by weight ethanol aqueous solution is temporarily filled, bubbles are reduced compared to the case where no temporary filling is performed. If a 70% by weight or more ethanol aqueous solution was temporarily filled, a 10% by weight ethanol aqueous solution could be filled without air mixing.

(Example 7)
In Example 5, an experiment was performed in the same manner as in Example 5 except that a 50 wt% aqueous ethanol solution containing 50 wt% ethanol and 50 wt% distilled water was contained in the tank 31. The results are shown in FIG.

  FIG. 11 is a graph showing the relationship between the concentration of the temporarily filled ethanol aqueous solution and the bubbles in the fuel cell fuel container after filling the 50 wt% ethanol aqueous solution when the fuel cell fuel container is filled with the 50 wt% ethanol aqueous solution. It is. According to this, when a 50 wt% aqueous ethanol solution is filled in a fuel cell fuel container, the bubble volume is zero until the concentration of the temporarily filled ethanol aqueous solution is about 70 wt%. No bubbles were seen in chamber 3. The bubble volume gradually increased as the concentration of the temporarily filled ethanol aqueous solution decreased. Since the concentration of the temporarily filled ethanol aqueous solution is higher than the concentration of the ethanol aqueous solution to be filled, no experiment was conducted at a concentration of the temporarily filled methanol aqueous solution lower than 50% by weight. Assuming that the bubble volume in the fuel storage chamber 3 is constant when the concentration of the temporarily filled ethanol aqueous solution is lower than 50% by weight.

  As is clear from the graph shown in FIG. 11, when 50% by weight ethanol aqueous solution is filled, if the 55% by weight or more ethanol aqueous solution is temporarily filled, bubbles are reduced compared to the case where no temporary filling is performed. If a 70% by weight or more ethanol aqueous solution was temporarily filled, a 50% by weight ethanol aqueous solution could be filled without mixing air.

  In the embodiment, the fuel cell fuel container as shown in FIG. 1 is used for explanation. However, the liquid fuel filling method of the present invention fills the liquid fuel in any fuel cell fuel container for replenishing the fuel cell with the liquid fuel. It is also possible to use it.

  Further, in the embodiment shown here, after temporarily filling methanol or ethanol is discharged, separately prepared main filling methanol or ethanol is injected. However, the concentration of temporary filling methanol or ethanol is about 50% or higher. In this case, even if the methanol or ethanol used for the temporary filling is used as the main filling methanol or ethanol, the effect of filling without mixing air of the present invention can be obtained.

  As described above, in the liquid fuel filling method of the present invention, before filling the fuel container for the fuel cell with the liquid fuel, a liquid having a higher concentration than the liquid fuel of the same type as the liquid fuel to be filled is used for the fuel cell. Since the fuel is supplied to the fuel container, the wettability of the inner wall surface of the fuel container for the fuel cell and the piston-shaped partition wall member is improved, and bubbles are prevented from sticking to the inner wall surface of the fuel container and the piston-shaped partition wall member. The liquid fuel can be filled without mixing air into the liquid fuel to be filled thereafter.

Center cross-sectional front view of fuel cell fuel container 1 is an enlarged cross-sectional view of the valve portion in the closed state in FIG. Schematic diagram showing one embodiment of filling a fuel cell fuel container with fuel Schematic diagram showing another embodiment of filling a fuel container for a fuel cell with fuel The graph which shows the relationship between the density | concentration of the temporarily filling methanol aqueous solution in 10 weight% of this filling methanol aqueous solution, and the bubble in a fuel container. The graph which shows the relationship between the density | concentration of the temporarily filling methanol aqueous solution in 20 weight% of this filling methanol aqueous solution, and the bubble in a fuel container. The graph which shows the relationship between the density | concentration of the temporarily filling methanol aqueous solution in 30 weight% of this filling methanol aqueous solution, and the bubble in a fuel container. The graph which shows the relationship between the density | concentration of the temporarily filling methanol aqueous solution in 50 weight% of this filling methanol aqueous solution, and the bubble in a fuel container. The graph which shows the relationship between the density | concentration of the temporarily filling methanol aqueous solution in 10 weight% of this filling ethanol aqueous solution, and the bubble in a fuel container. The graph which shows the relationship between the density | concentration of the temporary filling methanol aqueous solution in 30 weight% of this filling ethanol aqueous solution, and the bubble in a fuel container. The graph which shows the relationship between the density | concentration of the temporarily filling methanol aqueous solution in 50 weight% of this filling ethanol aqueous solution, and the bubble in a fuel container.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel container for fuel cells 2 Container body 3 Fuel storage chamber 4 Air chamber 5 Bulkhead member
5a, 5b Seal part 7 Valve 8 Elastic body
21 Outer container
22 Lid
23 Inner container
24 connections
25 passage
30,31,35 tanks
32,33,34 tubes
40 sleeves
52 Support member
71 housing
72 stem
73 Spring
74 Disc
75 Sealant F Liquid fuel F 'High concentration liquid G Compressed gas
P1, P2 Tank Q Cock

Claims (7)

  In a method of filling a liquid fuel for a fuel cell containing liquid fuel for a fuel cell with the liquid fuel, the liquid fuel of the same type as the liquid fuel to be filled before filling the liquid fuel in the fuel cell fuel container A liquid having a concentration higher than that of the fuel cell is supplied to the fuel container for the fuel cell, and then the supplied high-concentration liquid is discarded, and then the liquid fuel is filled in the fuel container for the fuel cell. Liquid fuel filling method.   2. The liquid fuel filling method according to claim 1, wherein the liquid fuel is methanol or a methanol aqueous solution.   3. The liquid fuel filling method according to claim 2, wherein the high-concentration liquid is an aqueous methanol solution of 50% by weight or more.   4. The liquid fuel filling method according to claim 3, wherein the high-concentration liquid is an aqueous methanol solution of 70% by weight or more.   The liquid fuel filling method according to claim 1, wherein the liquid fuel is ethanol or an aqueous ethanol solution.   6. The liquid fuel filling method according to claim 5, wherein the high-concentration liquid fuel is an ethanol aqueous solution of 50% by weight or more.   The liquid fuel filling method according to claim 6, wherein the high-concentration liquid fuel is an ethanol aqueous solution of 70% by weight or more.

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