Fuel-Cell Comprising Capillaries

Abstract

A fuel cell comprising a reaction chamber; a plurality of capillary tubes configured to permit a fuel component to flow there through, the capillary tubes being arranged in bundles in adjacent segments within the reaction chamber; a plurality of electrodes, at least one of the plurality of electrodes passing through each of the plurality of capillary tubes, being against each of the plurality of capillary tubes, or passing through and being against each of the plurality of capillary tubes; and a plurality of counter-electrodes, Each electrode extends beyond ends of its respective capillary tube, and electrodes associated with capillary tubes of a segment are electrically connected to one another at each end at substantially the same electrical potential. Each segment has a wall section to which is attached at least one of the counter-electrodes or wherein the wall section at least partially forms at least one of the counter-electrodes.

Description

FIG. 1 shows a cylindrical housing 1, in which six similarly adjacent segments 2-7 are provided with a plurality of capillary tubes 8, through and/or against which a fuel component flows and which are arranged in bundles (see FIG. 3).

In the present case, the capillary tubes 8 have a radially inner cloverleaf profile 9, which is surrounded by a lattice-like structure as the electrode 10, which in turn is provided with a radially external catalyst 11. A radially external membrane 12 surrounds the structure of the capillary tube 8. Since the profile 9 consists of an electrically conductive material that supports the capillary tube 8, and this material is especially a metal, preferably titanium, the electric potential on the lattice-like structure and on the profile 9 itself can be tapped as an electrode 10 led out at both ends.

The electrodes 10 and in this case the profiles 9 of each segment 2-7 as well are electrically connected in parallel and are also at essentially the same electric potential, as shown in FIG. 3 with the examples of segments 3, 5, and 7.

In the first embodiment, each segment 2 to 7 has its own walls 13 to 18, which in the view according to FIG. 3 run annularly around the capillary tubes 8 of each segment 2-7, so that two spaced separating walls, for example, 19, 20, are formed between, for example, the segments 5 and 6 (see also FIG. 6).

The electrically conductive walls 13 to 18 themselves constitute the counterelectrodes, and the segments 3, 5, 7 in FIG. 3 display the connection of the parallel-connected electrodes 10 of the capillary tubes 8 of the segments 3, 5, 7 counter to the connecting strips of the walls 13, 15, 17 of the respective adjacent segments 2, 4, 6, which walls 13, 15, 17 are designed as counterelectrodes.

The housing 1 is sealed at both axial ends by cover plates 21, 22, which are penetrated by the capillary tubes 8, which terminate open and freely accessible. The cover plates 21, 22, which have the same design, grip the arrangement of separating walls 19, 20 between adjacent segments 5, 6 and are also provided with spoke-like separating webs 23, 24. Enclosed between the separating webs 23, 24 and an outer ring of the cover plate 21, the wall 16 passes through the cover plate 21 with an exact fit. A reaction chamber located below is axially sealed by a panel 25 that encloses and holds the capillary tubes 8.

The walls 13-18 of the segments 2-7 are held apart from the inner wall 96 of the housing 1 by the cover plates 21, 22. In addition, the two separating walls 26, 27 and the other separating walls formed between the individual segments 2 to 7 (see FIG. 5) are provided with openings 28, 29, which preferably lie opposite each other, so that a flow exchange of an electrolyte inside the housing and the segments 2-7 is largely possible.

A preferred embodiment, which is designed here, by way of example, as a direct methanol fuel cell, is further explained with reference to FIGS. 7 to 13.

The fuel cell 30 according to FIG. 7 is essentially cylindrical in shape. The reaction takes place inside a cylindrical housing 31 (see also FIG. 13), which is provided with flanges 32, 33 for additional attachments.

In the fuel cell 30, a plurality of capillaries 34 is again bundled in six segments 35 to 40 (see FIG. 11). The capillary tubes 34, which have the same design, have a coiled core as an electrode 41. However, a tubular electrode is preferred, whose surface has a lattice-like design, is covered with a catalyst, and consists of a titanium expanded metal mesh or titanium wire cloth. Finally, the electrode is annularly surrounded by a membrane 42. In the present specific embodiment of a direct methanol fuel cell, this electrode is a cathode.

In this embodiment, the cores of the capillary tubes 34, as electrodes 41, are electrically connected in parallel at both ends at essentially the same potential.

Alternatively, it can be provided that the electrodes 41 of a segment 35-40 are connected in parallel at both ends and in each case counter to the same counterelectrodes (the anodes in the method of operation described here) of adjacent segments.

In this regard, it has been found to be advantageous to provide a switch for the connection, especially an electric/electronic switch, with which the voltage or the power output can be freely varied by series connection or parallel connection.

The segments 35 to 40 are separated from each other in spoke-like fashion by common separating walls 43, 44 (see FIG. 9), and sealing measures are not necessary here.

The separating wall 45 illustrated in FIG. 12 is provided on both sides with identically designed counterelectrodes 46, 47 on an electrically nonconductive core 58. The counterelectrode 46 has a lattice-like mount 49 for a catalyst on a support sheet 48. This mount 49 consists especially of a titanium expanded metal mesh or titanium wire cloth.

As a result, each bundle of capillary tubes 34 of a segment 35-40 is enclosed by two obliquely opposite counterelectrodes.

For electrical connection of the counterelectrodes 46, 47, the separating walls 45 have opposite connectors 52, 53, which project axially and are provided at both ends with an extension 50, 51 of the support sheet 48. The separating walls 45, together with the capillary tubes 34, are held in cover plates 54, 55 and pass through them. Furthermore, the cover plates 54, 55 are provided with grooves 56, 57, which are arranged in spoke-like fashion, for holding the separating walls 45. The connectors 53 of the electrodes 46, 47 are led out through rectangular openings 59 (see FIG. 11).

The sections according to FIGS. 9 and 10 show that the capillary tubes 34 also pass through the cover plates 54, 55 and project from them and are open at their ends. The electrodes 41 and/or the connectors of the counterelectrodes are connected by means of head pieces 93, 94 designed as plates (see the connectors 86-89 of the separating walls 43, 44 according to the sectional drawing shown in FIG. 9).

A gas, in this case air, can flow through the capillary tubes 34, which are open at the ends. To guarantee that the gas can flow through reliably, a pressure chamber 60 is formed at the upper end of the capillary tubes. In the present embodiment, a ventilator 61 under an opening 80 in the pressure chamber housing 81 ensures that a positive pressure relative to ambient pressure (though only a slight positive pressure) prevails in the pressure chamber 60. However, this slight positive is sufficient to enable air to flow through the capillary tubes 34. After flowing through the capillary tubes 34, the air enters a chamber 62 and escapes to the outside through openings 63 in a housing 64. The pressure chamber housing 81 is shaped like a hat and secured against the upper flange 32 of the housing 31. Standard sealing measures in the form of an 0 ring 95 can also be provided.

The chamber 62 can also serve as a collecting chamber for a liquid phase 65 emerging from the capillary tubes 34, for example, condensation water in the present case, or for a possible combustion product in a fuel cell with a different configuration. If necessary, an additional collecting chamber can also be provided for this purpose beneath the chamber 62. The condensation water can be disposed of, or, alternatively, possibly after a treatment, fed back into the combustion circulation as a fuel component.

A fuel mixture consisting of water and methanol is used in the fuel cell 30. This fuel mixture is fed to the reaction chambers 68, 69 of the segments through a common, closed-end feed line 66, for which purpose the feed line 66 is provided with openings 67 and forms part of the tip of each segment. The reaction chambers 68, 69 are filled with acidic methanol 70, 71 as the electrolyte. To ensure that the fuel mixture reliably enters the reaction chambers 68, 69, one pump 72, 73 for each fuel component is provided in a pump chamber 75. Whereas methanol enters the system from the outside through a pipe connection 74, the liquid phase 65, if water (but especially water from a separately constructed tank, e.g., in a chamber 76), can be fed to the combustion process from an internal source.

The pump chamber 75 is arranged at the opposite end from the pressure chamber 60, so that these two chambers 75, 60 enclose the housing 31 with its reaction chambers between them.

A control system (not shown) is provided in another chamber 77 and can adjust the ratios of the individual components of the fuel mixture, water and methanol in this case, in an optimum way by automatically controlling the pumps 72, 73.

The chambers 62, 75, 76, and 77 are placed one within the other in the manner of nested boxes and are tightened against the lower flange 33 of the housing 31 by means of an end plate 78 and, in the present case, four screws 79. The construction principle allows the addition of additional chambers or ventilators for cooling the electronics of the control system. If necessary, it is also possible to attach another fuel cell, but in this case it is necessary to provide sufficient spacing, so that air can enter the pressure chamber 60 through the opening 79 in the pressure chamber housing 81.

The fuel cell 30 is designed for operation with exclusively vertically rising capillary tubes and a pressure chamber 60 at the top. Since the acidic methanol 70, 71 does not fill the reaction chambers 68, 69 as far as the cover plate 54, a free space 82, 83 is left above the acid methanol 70, 71. Gaseous reaction products, in the form of CO₂ in the present case, collect in these free spaces 82, 83 and are discharged to the outside through an exhaust gas line 84 with openings 85.

As the sectional drawings according to FIGS. 9 and 10 also show, the exhaust gas line 84 continues the feed line 66 centrally between the adjacent tips of the segments, and the walls of the feed line 66 and of the exhaust gas line 84 constitute one of the boundaries of the reaction chambers 67, 68. However, no special sealing measures are necessary between the common separating walls 43, 44 and the feed line 66 and exhaust gas line 84.

In addition, level sensors 90 to 93, which monitor the filling level of the methanol 70, 71 in the reaction chambers 68, 69, are provided to ensure reliable operation of the fuel cell 30. Since the separating walls 43, 44 are installed without a tight seal, it is sufficient to monitor the filling level of a single reaction chamber 68. It is thus guaranteed that free spaces 83, 84 are present above the acidic methanol 70, 71 and that the filling level is sufficiently high. If one limit or the other is exceeded, the combustion process of the fuel cell is stopped.

FIG. 14 shows a horizontal section of another embodiment of a fuel cell of the invention, which again has six sectors 100-105, each with bundles of capillary tubes 106. In contrast to the previously described embodiment, the sectors 100-105 are separated from each other by two separating walls, for example, the sectors 100 and 101 are separated from each other by the two parallel separating walls 107, 108. A free space 109, which is filled with an electrolyte, is left between the pairs of separating walls 107, 108. This free space 109 is accessible through opposing openings 110, 111 in the separating walls 107, 108, so that the reaction chambers 112, 113 of the two sectors 100, 101 also communicate with each other.

Each separating wall 107, 108 is provided with a counterelectrode of the type explained at the beginning. The free ends of capillary tubes 206 and connectors 114 of the separating walls 107, 108 penetrate and are held by cover plates 115. This is illustrated in FIG. 15, which shows a sectional drawing through a pressure chamber housing 116.

Claims

1.-36. (canceled)

37. A fuel cell comprising: a reaction chamber;a plurality of capillary tubes configured to permit a fuel component to flow there through, the capillary tubes being arranged in bundles in adjacent segments within the reaction chamber;a plurality of electrodes, at least one of the plurality of electrodes passing through each of the plurality of capillary tubes, being against each of the plurality of capillary tubes, or passing through and being against each of the plurality of capillary tubes; anda plurality of counter-electrodes,wherein each electrode extends beyond ends of its respective capillary tube,wherein electrodes associated with capillary tubes of a segment are electrically connected to one another at each end at substantially the same electrical potential, andwherein each segment has a wall section to which is attached at least one of the counter- electrodes or wherein the wall section at least partially forms at least one of the counter- electrodes.

38. The fuel cell of claim 37, wherein the segments are circular segments.

39. The fuel cell of claim 37, wherein the electrodes of a capillary tube of each segment are electrically connected to the counterelectrode of the adjacent segment.

40. The fuel cell of claim 37, wherein the electrodes are electrically connected to one another at their adjacent ends.

41. The fuel cell of claim 37, further comprising a switch and electrical connections are capable of being preset by the switch.

42. The fuel cell of claim 37, wherein each segment has its own wall.

43. The fuel cell of claim 42, wherein two adjacent segments have wall sections which face each other and form two spaced separating walls.

44. The fuel cell of claim 37, wherein two adjacent segments share a common separating wall.

45. The fuel cell of claim 43, wherein the separating walls are constructed without a seal.

46. The fuel cell of claim 43, wherein each of the separating walls has a separately constructed counterelectrode which constitutes the counterelectrode of the respective segment.

47. The fuel cell of claim 44, wherein the common separating wall has a counterelectrode on each side.

48. The fuel cell of claim 47, wherein each of the counterelectrodes comprises a support sheet, and a lattice-shaped mount for a catalyst, the lattice-shaped mount covering the support sheet.

49. The fuel cell of claim 37, wherein each of the capillary tubes comprises a lattice-shaped core comprised of titanium, a catalyst surrounding the lattice-shaped core, and a membrane surrounding the catalyst.

50. The fuel cell of claim 48, wherein at least one of the support sheet and the lattice-shaped mount is comprised of titanium.

51. The fuel cell of claim 37, wherein ends of the capillary tubes are open so that a gas can flow through each of the capillary tubes.

52. The fuel cell of claim 51, further comprising a pressure chamber formed at one of the open ends of each of the capillary tubes, and a ventilator for admitting atmospheric air into the pressure chamber.

53. The fuel cell of claim 52, further comprising a common, closed-end feed line for the fuel component, the feed line extending between the segments and having openings through which the fuel component can flow into the reaction chamber.

54. The fuel cell of claim 37, further comprising an exhaust gas line extending from outside of the fuel cell and having openings through which a gaseous reaction product in the reaction chamber can flow into the exhaust gas line and out of the fuel cell.

55. The fuel cell of claim 53, further comprising an exhaust gas line extending from outside of the fuel cell and having openings through which a gaseous reaction product in the reaction chamber can flow into the exhaust gas line and out of the fuel cell.

56. The fuel cell of claim 55, wherein the exhaust gas line is a continuation of the feed line.

57. The fuel cell of claim 53, further comprising: a pump chamber formed at the other of the open ends of each of the capillary tubes; anda pump installed in the pump chamber and connected to the feed line.

58. The fuel cell of claim 57, further comprising: pumps for pumping the respective individual components of the fuel component into the feed line; anda control system for automatically controlling operation of the pumps to optimally adjust proportions of the respective individual fuel components.

59. The fuel cell of claim 58, wherein the individual fuel components comprise water and methanol.

60. The fuel cell of claim 52, wherein the fuel cell is oriented that the capillary tubes are disposed vertically and the pressure chamber is disposed above the reaction chamber.

61. The fuel cell of claim 60, further comprising a collecting chamber for collecting a liquid phase emerging from the plural capillary tubes.

62. The fuel cell of claim 61, wherein the liquid phase is water, and further comprising a means for returning the water to the reaction chamber.

63. The fuel cell of claim 37, wherein the reaction chamber is filled with acidic methanol.

64. The fuel cell of claim 37, further comprising at least one level sensor for monitoring a filling level of the fuel component in the reaction chamber.

65. The fuel cell of claim 63, wherein a free space remains above the acidic methanol.

66. The fuel cell of claim 64, wherein if the filling level is outside a range of levels, a reaction process occurring in the fuel cell is stopped.

67. The fuel cell of claim 37, further comprising: a cylindrical housing having opposite first and second axial ends;a first cover plate covering the first axial end; anda second cover plate covering the second axial end, wherein the segments are disposed inside the cylindrical housing with the ends of each of the capillary tubes extending through the first and second cover plates.

68. The fuel cell of claim 67, wherein each of the first and second cover plates are configured to grip the segments and hold the segments in place, each of the first and second cover plates further comprising panels in which ends of the capillary tubes are mounted.

69. The fuel cell of claim 68, further comprising connectors electrically connected to the counter-electrodes, and wherein the connectors extend through the first and second cover plates.

70. The fuel cell of claim 67, wherein the first and second cover plates have grooves on a side surface thereof, holding the segments in place.