BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing aspects, as well as many of the attendant advantages and features of this invention will become more apparent by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
FIG. 1 is an elevation view of a fuel cell having a fuel flow board in accordance with the first embodiment of the invention;
FIG. 2 shows the cross-section view of FIG. 1;
FIG. 3 shows the plan view of the fuel flow board in FIG. 1).;
FIG. 4 shows the cross-section view of a fuel flow board for a fuel cell according to the second embodiment of the invention;
FIG. 5 shows the cross-section view of a fuel flow board for a fuel cell according to the third embodiment of the invention;
FIG. 6 shows the exploded cross-section view of a fuel flow board for a fuel cell according to the forth embodiment of the invention;
FIG. 7 shows the cross-section view of FIG. 6;
FIG. 8 shows the exploded cross-section view of a fuel flow board for a fuel cell according to the fifth embodiment of the invention; and
FIG. 9 shows the cross-section view of FIG. 8.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an elevation view of a fuel cell having a fuel flow board according to the first embodiment of the invention, FIG. 2 shows the cross-section view of FIG. 1, and FIG. 3 shows the plan view of the fuel flow board in FIG. 1. Referring to FIG. 1, FIG. 2 and FIG. 3, a fuel flow board 10 for a fuel cell includes a first surface 101 and a second surface 102 to be contacted with an upper fuel cell board 20 and a lower fuel cell board 20, respectively. The fuel cell board 20 may be a power generator made from the manufacture process of printed circuit boards (PCBs). For example, the fuel cell board 20 is a direct methanol fuel cell (DMFC), of which substrate may include multi-layers of FR4 substrates, FR5 substrates, epoxy resin substrates, glass fiber substrates, ceramic substrates, polymeric plastic substrates, or composite substrates. Pluralities of cores with MEAs 201 are sandwiched in the sandwiched layers of substrates, in which the MEAs 201 are provided to perform electrochemical reactions and output power. The substrate of the fuel flow board 10 may be composed of FR4 substrates, FR5 substrates, epoxy resin substrates, glass fiber substrates, ceramic substrates, polymeric plastic substrates, or composite substrates. The first surface 101 or the second surface 102 of the fuel flow board 10 individually includes fuel flowing channels 103. The channels 103 are embedded in the surfaces 101, 102 of the fuel flow board 10, so as to form a flow-guiding structure, and include a plurality of inlets 103a, a plurality of leading portions 103b and a plurality of contact portions 103c.
Each inlet 103a of the channel 103 penetrates through the side of the fuel flow board 10 to connect with an external fuel supplier (not shown). The leading portion 103b is a concave structure on the surface of the fuel flow board 10, and connects to the inlet 103a and a corresponding contact portion 103c. The contact portion 103c includes parallel trenches 103d that are rectangular concave structures on the surface of the fuel flow board 10. The trenches 103d on the first surface 101 of the fuel flow board 10 and the trenches 103d on the second surface 102 of the fuel flow board 10 are spaced apart and interlaced each other. The trench 103d has a width W and a depth H. The fuel flow board 10 can be designed to have a thickness approximate to the depth H such that the thickness of the fuel flow board 10 can be substantially minimized as the depth H of the trench 103d is maintained.
FIG. 4 shows the cross-section view of a fuel flow board for a fuel cell according to the second embodiment of the invention. Each contact portion 103c comprises a plurality of trenches 103d defined in parallel. The trenches 103d are trapezoid concave structures on the surface of the fuel flow board 10.
FIG. 5 shows the cross-section view of a fuel flow board for a fuel cell according to the third embodiment of the invention. Each contact portion 103c comprises a plurality of trenches 103d defined in parallel, and the trenches 103d are half-hexagonal concave structures on the surface of the fuel flow board 10.
Though several embodiments are described above, the invention is not limited to the geometry of the trench 103d as illustrated in FIG. 2, FIG. 4 and FIG. 5. Other structures or geometries are also claimed within the scope of the invention, as long as the trenches 103d on the first surface ).101 of the fuel flow board 10 and the trenches 103d on the second surface 102 of the fuel flow board 10 are spaced apart and interlaced each other, and the width W and depth H of the trenches 103d as well as the ratio of width W to depth H are designed to decrease their surface tension, preventing bubbles from accumulating and blocking channels. Moreover, the trenches 103d of the contact portion 103c are preferably deployed corresponding to the position of each MEA 201 in the fuel cell board 20.
FIG. 6 shows the exploded cross-section view of a fuel flow board for a fuel cell according to the forth embodiment of the invention. FIG. 7 shows the cross-section view of FIG. 6. A fuel flow board 40 is in the form of a channel-separating structure, which is composed of a first substrate 401 and two second substrates 402, and two sides of the first substrate 401 are individually connected to second substrates 402. A contact portion 401a is formed on the surface of the first substrate 401, and a first leading portion 402a is formed on the surface of the second substrate 402. Second leading portions 401b corresponding to the first leading portion 402a are respectively formed on two sides of each contact portion 401a, so the contact portions 401a, the second leading portions 401b and the first leading portions 402a of the first substrate 401 and the second substrate 402 constitute a fuel flowing channel after being combined. The first substrate 401 and the second substrate 402 separately include a first combination 401c and a second combination 402b that are opposite to each other. The first combination 401c and the second combination 402b are provided to integrate the first substrate 401 and the second substrate 402. The first leading portion 402a is concave inwardly for directing flow. One end, thereof, laterally passes through the fuel flow board 40 to form an inlet in communication with an external fuel supplier (not shown), and the other end thereof corresponds to and connects with the second leading portion 401b of the contact portion 401a. Each contact portion 401a includes a plurality of parallel trenches 103d that are concave structures on the surface of the fuel flow board 40. The second leading portion 401b is concave inwardly for connecting the contact portion 401a with the first leading portion 402a to guild fluid thereby.
FIG. 8 shows the exploded cross-section view of a fuel flow board for a fuel cell according to the fifth embodiment of the invention. FIG. 9 shows the cross-section view of FIG. 8. A first substrate 501 and two second substrates 502 separately include first combinations 503 and second combinations 504. The first combinations 503 and the second combinations 504 constitute a coupling structure for combining the first substrate 501 and the second substrate 502. For example, the first combination 503 may be an inserting hole punching along the planar direction, and the second combination 504 may be a protruding bar extending in the planar direction. The inserting hole and the protruding bar form the coupling structure. After the protruding bar is inset into the inserting hole, the inserting hole and the protruding bar are fastened mutually, and hence the first substrate 501 and the second substrates 502 are integrated with each other.
Furthermore, the first leading portion 505 and the second leading portion 506 are formed on the surface of the second substrate 502, and the contact portion 507 is formed on the surface of the first substrate 501. The first leading portion 505 may shape a uniform diverged structure or a uniform converged structure by which the flow out of the first leading portion 505 is distributed to each second leading portion 506 averagely, or the flow from each second leading portion 506 is collected into the first leading portion 505 averagely.
While the invention has been particularly shown and described with reference to the preferred embodiments thereof, these are, of course, merely examples to help clarify the invention and are not intended to limit the invention. It will be understood by those skilled in the art that various changes, modifications, and alterations in form and details may be made therein without departing from the spirit and scope of the invention, as set forth in the following claims.
Patent Application
20070292740
