Abstract:
A fuel cell includes a substrate layer, a first electrode, a second electrode, a first chamber layer and a second chamber layer, and all of which are integrally formed by co-firing. The substrate layer includes a first surface and a second surface opposite to the second surface, and the first electrode, the second electrode are formed on the first and second surfaces, respectively. The first chamber layer, disposed on the first electrode, includes a first flow passage and a first fuel chamber connected thereto, and a first gas passes the first flow passage, enters the first fuel chamber and contacts the first electrode. The second chamber, disposed on the second electrode, includes a second flow passage and a second fuel chamber connected thereto, and a second gas passes the second flow passage, enters the second fuel chamber and contacts the second electrode.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a fuel cell, and in particular relates to an easily fabricated fuel cell. 
     2. Description of the Related Art 
       FIG. 1  shows a conventional fuel cell  1 , comprising a substrate  10 , a first electrode  21 , a second electrode  22 , a first cover layer  31  and a second cover layer  32 . The substrate  10  comprises a first surface and a second surface. The first electrode  21  is formed on the first surface, and the second electrode  22  is formed on the second surface. The first cover layer  31  is adhered to the first surface by an adhesive (glass cement)  40 , and the second cover layer  32  is adhered to the second surface by an adhesive  40 . The first cover layer  31  and the second cover layer  32  are stainless steel. Conventionally, adhesion of the adhesive  40  deteriorates with time and temperature, and the first cover layer  31  and the second cover layer  32  are thus separated from the substrate  10 . Additionally, the conventional fabrication process for combining the first cover layer  31  and the second cover layer  32  to the substrate  10  by adhesive  40  is complex. 
     BRIEF SUMMARY OF THE INVENTION 
     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
     A fuel cell is provided. The fuel cell comprises a substrate layer, a first electrode, a second electrode, a first chamber layer and a second chamber layer. The substrate layer comprises a first surface and a second surface, and the first surface is opposite to the second surface. The first electrode is formed on the first surface. The second electrode is formed on the second surface. The first chamber layer is disposed on the first electrode, wherein the first chamber layer comprises a first flow passage and a first fuel chamber, the first flow passage is connected to the first fuel chamber, and a first gas passes the first flow passage, enters the first fuel chamber and contacts the first electrode. The second chamber layer is disposed on the second electrode, wherein the second chamber layer comprises a second flow passage and a second fuel chamber, the second flow passage is connected to the second fuel chamber, and a second gas passes the second flow passage, enters the second fuel chamber and contacts the second electrode, wherein the substrate layer, the first electrode, the second electrode, the first chamber layer and the second chamber layer are integrally formed by co-firing. 
     In the embodiment of the invention, materials of the substrate layer, the first chamber layer and the second chamber layer are selected to be matched. Additionally, the substrate layer, the first chamber layer and the second chamber layer are co-fired to be integrally formed. The structure strength and reliability of the fuel cell is improved. As well, the fuel cell is easier assembled, and a sealing problem is prevented. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  shows a conventional fuel cell; 
         FIG. 2  is an exploded view of a fuel cell of a first embodiment of the invention; 
         FIG. 3   a  is a sectional view of the fuel cell along I-I direction of  FIG. 2 ; 
         FIG. 3   b  is an assembly view of the first embodiment of the invention; 
         FIG. 3   c  is a sectional view of the fuel cell along II-II direction of  FIG. 2 ; 
         FIG. 4   a  shows a plurality of fuel cells stringed up as a cell stack; 
         FIG. 4   b  shows the fuel cells of  FIG. 4   a, which are parallelly connected;    
         FIG. 4   c  shows a modified embodiment of the invention, wherein the fuel cells are serially connected; 
         FIG. 5  shows a fuel cell of a second embodiment of the invention; 
         FIG. 6  shows a fuel cell of a modified embodiment of the second embodiment of the invention; and 
         FIG. 7  shows another embodiment of the invention, wherein a plurality of cell stacks are integrated in a cell unit. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims. 
       FIG. 2  is an exploded view of a fuel cell  100  of a first embodiment of the invention.  FIG. 3   a  is a sectional view of the fuel cell along I-I direction of  FIG. 2 .  FIG. 3   b  is an assembly view of the first embodiment of the invention. With reference to  FIGS. 2 ,  3   a  and  3   b,  the fuel cell  100  of the first embodiment of the invention comprises a substrate layer  110 , a first electrode  111 , a second electrode  112 , a first chamber layer  120  and a second chamber layer  130 . The substrate layer  110  comprises a first surface  113  and a second surface  114 . The first surface  113  is opposite to the second surface  114 . The first electrode  111  is formed on the first surface  113 . The second electrode  112  is formed on the second surface  114 . 
     The first chamber layer  120  is disposed on the first electrode  111 . The first chamber layer  120  comprises a first flow passage  121  and a first fuel chamber  122 . The first flow passage  121  is connected to the first fuel chamber  122 . A first gas (oxygen)  101  passes the first flow passage  121  entering the first fuel chamber  122  to contact the first electrode  111 . The second chamber layer  130  is disposed on the second electrode  112 . The second chamber layer  130  comprises a second flow passage  131  and a second fuel chamber  132 . The second flow passage  131  is connected to the second fuel chamber  132 . A second gas (hydrogen)  102  passes the second flow passage  131  entering the second fuel chamber  132  to contact the second electrode  121 . The substrate layer  110 , the first electrode  111 , the second electrode  112 , the first chamber layer  120  and the second chamber layer  130  are combined by co-firing. 
     In the first embodiment, the first fuel chamber  122  and the second fuel chamber  132  are through holes. 
     The first gas (oxygen)  101  is ionized into oxygen ions. The oxygen ions enter the substrate layer  110 , moving to the second electrode  112 , and react with the second gas (hydrogen)  102  to generate water, heat and electricity. 
     In the fuel cell  100  of the first embodiment, the first chamber layer  120  is disposed on the first surface  113 , and the second chamber layer  130  is disposed on the second surface  114 . The first chamber layer  120  further comprises a third flow passage  123 . The second chamber  130  further comprises a fourth flow passage  133 . The substrate  110  further comprises a fifth flow passage  115  and a sixth flow passage  116 . The fifth flow passage  115  is connected to the first flow passage  121  and the fourth flow passage  133 . The sixth flow passage  116  is connected to the second flow passage  131  and the third flow passage  123 . 
       FIG. 3   c  is a sectional view along II-II direction of  FIG. 2 . With reference to  FIG. 2  and  FIG. 3   c,  the substrate layer  110  comprises wire holes  117 , the first chamber layer comprises wire holes  124 , and the second chamber layer  130  comprises wire holes  134 . The wire holes  117 ,  124  and  134  contain wires  1171 ,  1241  and  1341  to conduct the electricity generated by the fuel cell. 
     With reference to  FIG. 3   a,  the first electrode  111  comprises a first collecting film  1111 , the first collecting film  1111  is formed on a surface of the first electrode  111 , the second electrode  112  comprises a second collecting film  1121 , and the second collecting film  1121  is formed on a surface of the second electrode  112 . 
     The substrate layers comprises: (a) cerium oxide or zirconium oxide single-/co-doped with positive ion with +2 or +3 charges; (b) LaMo 2 O 9 ; or (c) Perovskite. 
     The first and second electrodes comprise: (a) Pt, Au, Pd, Rh, Ir, Ru, Os, Ni, Co and Fe; (b) LaSrMnO 3  or LaSrCoFeO 3 ; or (c) a compound of cerium oxide and LaSrMnO 3 , or a compound of cerium oxide and LaSrCoFeO 3 . In a modified embodiment, the first and second electrodes further comprise a second phase material for resisting carbonization, poisoning or vulcanization, such as copper or cerium oxide. 
     The first and second chamber layer comprise: (a) cerium oxide or zirconium oxide mixed with positive ion with +2 or +3 charges; (b) LaMo 2 O 9 ; (c) Perovskite; (d) magnesium aluminate spinel; (e) lanthanum aluminum oxide; or (f) aluminum oxide 
     The substrate layer, the first electrode, the second electrode, the first chamber layer and the second chamber layer are co-fired by electric furnace, atmosphere furnace, microwave sintering furnace, laser annealing or heat press. The co-firing temperature is between 600° C. and 800° C. (thin film process) or between 1300° C. and 1600° C. (thick film process). 
     The first and second electrodes are formed by screen print, inject print, spread or lift-off process. The thickness of the first and second electrodes is about 0.01 mm (thick film process) or between 10 μm and 20 nm (thin film process). 
     In the embodiment of the invention, materials of the substrate layer, the first chamber layer and the second chamber layer are selected to be matched. Additionally, the substrate layer, the first chamber layer and the second chamber layer are co-fired to be integrally formed. The structure strength and reliability of the fuel cell is improved. As well, the fuel cell is easier assembled, and a sealing problem is prevented. 
     With reference to  FIG. 4   a,  a plurality of fuel cells can be stringed up as a cell stack  100 ′. In the cell stack  100 ′, the first gas (oxygen)  101  travels in the fifth flow passage, the first flow passage and the fourth flow passage. The second gas (hydrogen)  102  travels in the sixth flow passage, the second flow passage and the third flow passage. A cover layer  141  is disposed on the top of the cell stack  100 ′, and a cover layer  142  is disposed on the bottom of the cell stack  100 ′. The cover layer  141  and the cover layer  142  limit flow paths of the first gas (oxygen)  101  and the second gas (hydrogen)  102 . The cell stack  100 ′ of the embodiment provides more electricity with a simplified structure and reduced dimension. 
     As shown in  FIG. 4   b,  the fuel cells of  FIG. 4   a  are parallelly connected to provide increased voltage.  FIG. 4   c  shows a modified embodiment of the invention, wherein the fuel cells are serially connected to provide increased voltage. 
       FIG. 5  shows a fuel cell  200  of a second embodiment of the invention comprising a substrate layer  210 , a first electrode  211 , a second electrode  212 , a first chamber layer  220 , a second chamber layer  230 , a first cover layer  251  and a second cover layer  252 . The substrate layer  210  comprises a first surface  213  and a second surface  214 . The first surface  213  is opposite to the second surface  214 . The first electrode  211  is formed on the first surface  213 . The second electrode  212  is formed on the second surface  214 . 
     The first chamber layer  220  is disposed on the first electrode  211 . The first chamber layer  220  comprises a first flow passage  221  and a first fuel chamber  222 . The first flow passage  221  is connected to the first fuel chamber  222 . A first gas (oxygen)  101  passes the first flow passage  221  entering the first fuel chamber  222  to contact the first electrode  211 . The second chamber layer  230  is disposed on the second electrode  212 . The second chamber layer  230  comprises a second flow passage  231  and a second fuel chamber  232 . The second flow passage  231  is connected to the second fuel chamber  232 . A second gas (hydrogen)  102  passes the second flow passage  231  entering the second fuel chamber  232  to contact the second electrode  221 . The substrate layer  210 , the first electrode  211 , the second electrode  212 , the first chamber layer  220  and the second chamber layer  230  are combined by co-firing. 
     The first electrode  211  comprises a first collecting film  2111 , the first collecting film  2111  is formed on a surface of the first electrode  211 , the second electrode  212  comprises a second collecting film  2121 , and the second collecting film  2121  is formed on a surface of the second electrode  212 . 
     In the fuel cell  200  of the second embodiment, the material of the elements and co-firing process are similar to the first embodiment. 
       FIG. 6  shows a fuel cell  200 ′ of a modified embodiment of the second embodiment of the invention, wherein the fuel cell  200 ′ comprise a first wire hole  241  and a second wire hole  242 . The first wire hole  241  is connected to the first fuel chamber  222  via a connection passage  223  allowing the first gas  101  to travel from the first fuel chamber  222  to the first wire hole  241 . The second wire hole  242  is connected to the second fuel chamber  232  via a connection passage  233  allowing the second gas  102  to travel from the second fuel chamber  232  to the second wire hole  242 . 
       FIG. 7  shows another embodiment of the invention, wherein a plurality of cell stacks  100 ′ are integrated in a cell unit  300 . The cell unit  300  comprises a first unit chamber  310  and a second unit chamber  320 . The cell stacks  100 ′ are parallelly arranged between the first unit chamber  310  and the second unit chamber  320 . Each cell stacks  100 ′ comprises a first connection hole  103 ′ and a second connection hole  104 ′. The first gas (oxygen)  101  travels in the first unit chamber  310 . The second gas (hydrogen)  102  travels in the second unit chamber  320 . The first gas (oxygen)  101  and the second gas (hydrogen)  102  enter each cell stacks  100 ′ via the first connection hole  103 ′ and second connection hole  104 ′. In the embodiment of  FIG. 7 , the cell unit  300  can be serially connected or parallelly connected to provide increased electricity. 
     While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.