JP4634728B2 - Fuel container for fuel cell - Google Patents

Description

  The present invention relates to a fuel container for a fuel cell that contains a liquid fuel such as an aqueous methanol solution supplied to a fuel cell such as a direct methanol fuel cell (DMFC) and supplies the fuel to the fuel cell, and in particular, a fuel storage chamber. The structure of the piston-shaped partition member which partitions the liquid fuel accommodated in and the compressed gas for ejection enclosed in the air chamber.

  Conventional containers for storing liquids include, for example, aerosol containers and cosmetic containers. Glass, metal, and plastic are used for the container body. By pressurizing the inside of these containers, when the nozzle is opened, the solution inside flows out in a spray state and is used.

  In these containers, the undiluted solution used as a medicine and the propellant for pressurizing the inside of the container are contained in a mixed state. Etc., a double-structured container is used (see, for example, Patent Document 1).

In the double structure container using the piston, it is necessary to seal the compressed gas in order to obtain the piston driving force, and as a technique for easily sealing the compressed gas in the manufacturing process, a protrusion is provided on a part of the bottom surface of the piston head, There has been proposed a structure in which when the piston is moved to the bottom surface, the first chamber in which the stock solution is accommodated and the second chamber in which the compressed gas is accommodated communicate with each other by tilting the piston (for example, see Patent Document 2).
Japanese Patent Publication No. 5-20148 JP-A-11-179250

  By the way, the use of a fuel cell as a small power source for a portable personal computer (notebook personal computer, PDA, etc.) and other devices has been studied, but a fuel container (for example, a fuel cartridge) for supplying fuel to the fuel cell is necessary. As the fuel, for example, a mixed solution of methanol and pure water or a mixed solution of ethanol and pure water has been studied for a direct methanol fuel cell (DMFC).

  In order to eject and supply liquid fuel from the fuel container described above, it is necessary to obtain a reliable operation of a piston-shaped partition member that pressurizes the liquid fuel by receiving the pressure of the enclosed compressed gas. In particular, when the discharge pressure is set to a low value of not more than 0.3 MPa and the fuel supply pump and pressure adjustment mechanism are not installed on the equipment side, the partition member can be reliably moved at this low pressure. Need to be configured so that

  For example, FIG. 6 shows a conventional structure example. The fuel container 100 includes a double-structured container main body including an outer container 101 and an inner container 102, and the inner container 102 has a fuel storage chamber 103 that stores liquid fuel between the outer container 101 and the inner container 102. Is formed in an air chamber 104 for containing compressed gas, and a piston-like partition member 105 is slidably disposed in the inner container 102, so that the fuel storage chamber 103 and the air chamber 104 are partitioned so that the volume can be varied. Being done.

  If the partition member 105 is less slidable when stored for a long time in a non-use state, and the partition member 105 is partially resistant to the wall of the inner container 102, as shown in the figure. Even if the upper seal 151 and the lower seal 152 are provided on the outer periphery without falling parallel, a uniform seal cannot be obtained, and the fuel storage chamber 103 and the air chamber 104 partially communicate with each other. There is a risk of bubbles (compressed gas) entering the liquid fuel from 104.

  That is, in order to supply the liquid fuel in the fuel storage chamber 103, when the liquid fuel is ejected by opening a valve (not shown), if the partition member 105 moves normally following this, the fuel storage chamber 103 and Although the pressure in the air chamber 104 is balanced, the internal pressure of the fuel storage chamber 103 is lower than the pressure in the air chamber 104 if the partition member 105 does not move following. Then, when the partition member 105 is tilted as described above, if compressed gas bubbles flow into the fuel storage chamber 103 from the air chamber 104 through the outer peripheral portion and mix, the pressure in the air chamber 104 decreases. As a result, the internal pressure of the fuel storage chamber 103 further decreases, and thereafter, even if liquid fuel remains in the fuel storage chamber 103, there is a problem that the liquid fuel cannot be supplied because the pressure is low.

  Even if the partition member 105 is not tilted, the compressed gas flows into the fuel storage chamber 103 side from the communication path near the valve due to the internal / external pressure difference accompanying the decrease in the internal pressure of the fuel storage chamber 103. There is also a possibility of causing a poor supply of liquid fuel.

  The present invention has been made in view of such points, and provides a fuel container for a fuel cell capable of preventing a collapse of a piston-shaped partition wall member to ensure reliable sliding and ejecting only liquid fuel by itself. It is intended.

  A fuel container for a fuel cell according to the present invention includes a container main body having a connection part for opening and supplying liquid fuel to an outer surface, and a fuel storage chamber formed inside the container main body for containing liquid fuel supplied to the fuel cell. And an air chamber that is formed inside the container body and communicates with the fuel storage chamber at the end and encloses compressed gas that generates stress for pushing out the fuel, and is movably disposed in the fuel storage chamber. Provided with a piston-like partition member that partitions the liquid fuel and the compressed gas, and a valve that cuts off communication between the fuel storage chamber and the connecting portion, and the fuel storage is provided on the bottom outer periphery of the partition member. A fall-preventing member that protrudes in the sliding direction along the wall surface of the chamber is provided.

  It is preferable that three or more fall prevention members are provided at substantially equal intervals in the circumferential direction. In addition, the partition member is provided with one seal portion that slidably contacts the wall surface of the fuel storage chamber on the peripheral surface, thereby ensuring sealing performance.

  It is preferable that a seal member that blocks a communication path between the fuel storage chamber and the air chamber is provided at a portion opposite to an end portion where the fuel storage chamber and the air chamber communicate with each other.

  In addition, it is preferable that the inner wall surface of the end portion of the fuel storage chamber is provided with a recess that allows the upper and lower portions of the partition member to communicate with each other when the partition member moves to the extreme end. Furthermore, it is preferable to provide an elastic body that biases the partition member toward the fuel storage chamber when the partition member is moved to the endmost portion of the fuel storage chamber.

  According to the fuel container for a fuel cell of the present invention as described above, a container body having a connection portion, a fuel storage chamber for storing liquid fuel, an air chamber for communicating with the fuel storage chamber and for containing compressed gas, and a fuel The partition member, which is movably disposed in the storage chamber, and a valve that cuts off the communication are provided. The partition member is provided with a fall-preventing member, so that the partition member can be stably slid and there is a sliding failure. However, the liquid fuel can be jetted and supplied by itself until the end without falling down and ensuring a good sealing state without causing a decrease in internal pressure.

  In addition, a seal can be secured by one line by the fall prevention member, and the vertical dimension is shortened compared with increasing the vertical dimension of the partition wall member to prevent the fall, leading to an increase in the fuel capacity.

  Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 is a front view of a central section of a fuel cell fuel container according to one embodiment, FIG. 2 is a sectional view (a) and a bottom view (b) of the partition member of FIG. 1, and FIG. FIG. 4 is an enlarged cross-sectional view of the valve portion, and is a cross-sectional view of the main part during operation. Moreover, FIG. 5 is sectional drawing of the partition member of other embodiment.

  A fuel container 1 for a fuel cell according to the embodiment shown in FIG. 1 contains a liquid fuel F for a fuel cell using a predetermined concentration of methanol and pure water or a mixed solution of ethanol and pure water, and is a direct methanol fuel cell (DMFC). And is attached to a fuel cell main body (not shown).

  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, and a 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. And 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 the fuel storage chamber 3 and the connecting portion 24 are disconnected from each other. It consists of a valve 7 and an elastic body 8 installed at the bottom of the container body 2 and capable of contacting 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 said cover body 22, and the valve | bulb 7 is installed.

  The inner container 23 has a cylindrical shape, and a 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 part of 3 and the bottom part of the air chamber 4 can communicate with each other at the end part. A recess 11 is formed on the inner wall surface of the lower end portion of the inner container 23 so as to extend in the vertical direction. The sealing of the compressed gas G into the air chamber 4 by the action of the recess 11 will be described later with reference to FIG.

  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 connecting portion 24 via the valve 7, and the liquid fuel F responds to the communication cutoff operation of the valve 7. Can be discharged. Details of the valve 7 will be described later with reference to FIG.

  A cylindrical wall 23b (see FIG. 4) 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. 23 is held.

  The piston-like partition member 5 slidably fitted into the inner container 23 is composed of an elastic seal member 51 and a support member 52, as shown in a sectional view and a bottom view in FIG. One seal portion 51a on the outer periphery of 51, particularly on the upper peripheral surface, comes into airtight contact with the inner wall of the cylindrical inner container 23, and the liquid fuel F is sealed in the fuel storage chamber 3 in the upper space. The seal member 51 is held by the support member 52 so that the fuel storage chamber 3 moves in a stable posture.

  Further, on the outer periphery of the bottom of the support member 52, four fall prevention members 53 that protrude in the sliding direction along the wall surface of the fuel storage chamber 3 are provided at substantially equal intervals in the circumferential direction. When the partition wall member 5 is in a horizontal state, the fall prevention member 53 is not in contact with the inner surface of the inner container 23 (may slide in contact), and when the partition wall member 5 is tilted so as to collapse. A part of the fall prevention members 53 is prevented from coming into contact and falling further, and the sealing state by one seal portion 51a is maintained and secured. Note that three or five or more fall prevention members 53 may be formed.

  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 stored in the air chamber 4, and the front liquid fuel F is changed by the pressure of the compressed gas acting on the back surface. When the pressure is increased and the valve 7 communicates, the liquid fuel F acts to be pushed out from the connecting portion 24.

  Note that the position of the partition member 5 changes according to the storage volume of the remaining liquid fuel F, and the pressure changes as the volume of the compressed gas G changes accordingly. The pressure which moves the partition member 5 is ensured so that it can do.

  In addition, the PTFE (polytetrafluoroethylene) coating or DLC (diamond-like carbon) that is non-eluting with respect to the liquid fuel F is applied to the sealing surface of the partition member 5 or the inner wall surface of the inner container 23, and further to both. It is preferable to apply a low friction coefficient coating by coating or the like to reduce the movement resistance of the partition member 5 and to ensure a reliable and good operation even when the pressure of the compressed gas G is low.

  A mechanism example of the valve 7 will be described. As shown in an enlarged view in FIG. 4, 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 a 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 via a sealing O-ring 76 attached to the outer periphery of the lower portion of the housing 71 with respect to the connection portion 24 of the container body 2. 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, blocking the communication path through which the compressed gas in the air chamber 4 flows into the fuel storage chamber 3. Yes.

  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). Thus, even if the valve element 74 (elastic material) in contact with the liquid fuel F expands due to swelling or the like, the volume change is regulated in the direction perpendicular to the valve opening / closing movement direction. Change is suppressed.

  The compressed gas to be sealed in the air chamber 4 is a gas that does not contain oxygen such as nitrogen, carbon dioxide, deoxygenated air, etc., and oxygen that adversely affects the reaction in the fuel cell is mixed into the liquid fuel F. Or it is preferable at the point which prevents that the liquid fuel F oxidizes.

  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.

  The partition member 5 descends as the compressed gas G is injected into the fuel storage chamber 3 through the valve 7, and the elastic body 8 contacts the bottom surface of the support member 52 at the position shown in FIG. The seal portion 51 a of the partition wall member 5 is located above the upper end of the concave portion 11 of the inner container 23. Further, when the compressed gas is further injected into the fuel storage chamber 3, the partition member 5 further moves to the bottom of the fuel storage chamber 3 by pressing and deforming the elastic body 8 as shown in FIG. 3. In this lowest state, the upper end portion of the recess 11 is located above the seal portion 51a of the partition member 5, and the lower end portion of the recess 11 opens below the partition member 5, and the recess 11 allows the upper and lower portions of the partition member 5 to be connected to each other. , And the compressed gas can be injected from the fuel storage chamber 3 into the air chamber 4.

  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 is raised to the position of FIG. 1 by the repulsive force of the elastic body 8 to close the communication of the recess 11 and return to the sealed state of the fuel storage chamber 3, and further gas discharge causes the partition member to 5 is moved up to the upper end of the inner container 23 with the pressure of the compressed gas in the air chamber 4 acting on the back thereof, and all the gas in the fuel storage chamber 3 is discharged, whereby the compressed gas G is discharged into the air chamber 4. Is enclosed. Thereafter, the fuel injection means is connected, and the liquid fuel F is injected into the fuel storage chamber 3 through the valve 7 while lowering the partition member 5, so that the liquid fuel F can be ejected and the fuel container 1 for the fuel cell. Can be configured.

  In FIG. 1, the elastic body 8 is constituted by a spring, but may be constituted by a cushion material having an elastic repulsive force.

  In the fuel container 1 of the present embodiment, when the liquid fuel F is stored in the fuel storage chamber 3 for a long period of time, the slidability of the partition wall member 5 is reduced. Even if there is a partial resistance to the wall of the vessel 23, the partition member 5 does not fall by the fall prevention member 53, and a uniform seal can be obtained by the single seal portion 51 a, and the fuel storage chamber 3 and the air chamber 4. And air bubbles (air) from the air chamber 4 can be reliably prevented from entering the liquid fuel F.

  In addition, when the internal pressure of the fuel storage chamber 3 decreases, the compressed gas easily flows into the fuel storage chamber 3 from the air chamber 4 through the joint between the inner container 23 in the vicinity of the valve 7 and the housing 71. By interposing the sealing material 75, the flow of the compressed gas into the fuel storage chamber 3 is prevented in the same manner as described above.

  Thereby, when the liquid fuel F in the fuel storage chamber 3 is supplied to the fuel cell, even if the following movement of the partition wall member 5 is insufficient and the internal pressure of the fuel storage chamber 3 is lower than the pressure in the air chamber 4, the air chamber 4, the pressure of the air chamber 4 can be maintained without flowing into the fuel storage chamber 3, and when the follow-up movement of the partition wall member 5 is recovered thereafter, the liquid fuel F stored in the fuel storage chamber 3 is removed. Can be supplied to the end.

  Next, FIG. 5 is sectional drawing which shows the partition member 6 of other embodiment. The partition member 6 is composed of a resin main body 61 and one O-ring 62. The O-ring 62 is mounted and held in a circumferential groove installed on the outer periphery of the main body 61 and is sealed at one place. In addition, on the outer periphery of the bottom of the main body 61, a fall prevention member 63 that protrudes in the sliding direction along the wall surface of the inner container 23 is provided as described above. When the partition wall member 6 is tilted so as to fall down, the fall-preventing member 63 prevents the wall member 6 from further falling due to contact with the wall surface of the inner container 23, thereby preventing a seal state by one O-ring 62 (seal part). Maintain and secure. Others are configured similarly and have similar functions.

  The fuel cell fuel container 1 is attached to a fuel cell and supplies fuel directly to the fuel cell. However, the fuel cell fuel container 1 is liquid to the fuel cell fuel container that can be reinjected by increasing the internal pressure. It can also be used as an injection fuel container for injecting the fuel F.

The center section front view of the fuel container for fuel cells in one embodiment of the present invention Sectional view and bottom view of the partition member of FIG. FIG. 1 is a cross-sectional view of the main part during the compressed gas sealing operation of FIG. Enlarged sectional view of the valve part Sectional drawing of the partition member of other embodiment The figure which shows the fall state of the partition member of the fuel container in the conventional structural example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel container for fuel cells 2 Container body 3 Fuel storage chamber 4 Air chamber 5,6 Partition member 7 Valve 8 Elastic body
11 Recess
21 Outer container
22 Lid
23 Inner container
24 connections
25 passage
51 Seal member
51a Seal part
53,63 Fall prevention member
52 Support member
61 Main unit
62 O-ring
71 housing
72 stem
73 Spring
74 Disc
75 Sealant F Liquid fuel G Compressed gas

Claims (6)

A container body having a connection for opening the outer surface and supplying liquid fuel;
A fuel storage chamber formed inside the container body and containing liquid fuel to be supplied to the fuel cell;
An air chamber that is formed inside the container body, communicates with the fuel storage chamber at the end, and encloses a compressed gas that generates stress for pushing out the fuel;
A piston-like partition member that is movably disposed in the fuel storage chamber and divides the liquid fuel and compressed gas;
A valve that cuts off communication between the fuel storage chamber and the connecting portion ;
The bottom outer periphery of the partition wall member, and the prevention member fallen projects in the sliding direction along the wall surface of the fuel storage chamber,
A concave portion communicating with the upper and lower portions of the partition member when the partition member is moved to the end portion on the inner wall surface of the end portion of the fuel storage chamber;
A fuel container for a fuel cell, comprising: an elastic body that urges the partition member toward the fuel storage chamber when the partition member is moved to the end of the fuel storage chamber. The fuel container for a fuel cell according to claim 1, wherein three or more of the fall prevention members are provided at equal intervals in the circumferential direction .   3. The fuel container for a fuel cell according to claim 1, wherein the partition wall member includes one seal portion that is in sliding contact with a wall surface of the fuel storage chamber on a peripheral surface thereof. In the site opposite to the end where the fuel storage chamber and the air chamber communicate with each other,
The fuel container for a fuel cell according to claim 1, further comprising a sealing material that blocks a communication path between the fuel storage chamber and the air chamber.   The fuel container for a fuel cell according to any one of claims 1 to 4, wherein a bottom portion of the fuel storage chamber and a bottom portion of the air chamber can communicate with each other at an end portion.   The fuel container for a fuel cell according to any one of claims 1 to 5, wherein the partition member includes an elastic seal member and a support member.

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