Patent Publication Number: US-2007099047-A1

Title: Regulated fuel cell device

Description:
FIELD OF THE INVENTION  
      This invention relates to a fuel cell device, particularly to a regulated fuel cell device being able to output steady DC voltage.  
     BACKGROUND OF THE INVENTION  
      Conventional fuel cells use hydrogen containing fuel, such as methanol, to form a current circuitry after an oxido-reduction reaction, so as to generate electrical power. It is observed from the voltage vs. current curve of such fuel cells that, when the loading current increases, the voltage reduces dramatically. Therefore, there is a need of a highly effective regulating circuit so as to supply a steady output voltage.  
       FIG. 1A  and  FIG. 1B  are schematic diagrams of a conventional DC regulating module  100 , wherein the DC regulating module  100  includes a circuit board  110 , at least one DC regulating control unit  120  and some passive units ( 130 ,  131 ), so as to transform an input voltage power into DC voltage power of various Volt levels. The DC regulating module  100  includes plural terminal  150  for supplying the steady DC voltage power to other circuit boards (not shown).  
      However, the fuel cell may also produce excessive moisture and a small amount of acidic substance after the generation of power by the chemical reaction. If an exposed regulating module  100  is used with the fuel cell, a permanent damage caused by short circuit from moisture or erosion of electronic components caused by acidic substances may arise. Thus, the DC regulating module  100  further includes a packaging device  140  for covering the DC regulating control unit  120  and passive units ( 130 ,  131 ) so as to protect the DC regulating control unit  120  and passive unit ( 130 ,  131 ). However, in the conventional regulating module  100 , the plural terminals  150  are still easily eroded by moisture or acidic substance. Thus, an improvement is needed for the regulating circuit used in the conventional fuel cell.  
     SUMMARY OF THE INVENTION  
      It is thus a primary object of this invention to provide a regulated fuel cell device being able to output a steady DC voltage.  
      It is another object of this invention to provide a regulated fuel cell device with reduced manufacturing cost by providing a regulating circuit on a substrate of the fuel cell.  
      It is a further object of this invention to provide a regulated fuel cell device, wherein the combination of the regulating circuit and a packaging device is able to insulate from erosion of moisture and acidic substances.  
      It is a further object of this invention to provide a regulated fuel cell device, where the combination of the regulating circuit and a packaging device increases the dissipation of heat generated by the DC regulating circuit.  
      According to one aspect of this invention, a regulated fuel cell device is provided, comprising a substrate, a DC regulating circuit and a packaging device. The substrate is made of a printed circuit board material and provided with more than one membrane electrode assembly. The DC regulating circuit is disposed on the substrate for receiving input voltage generated by the membrane electrode assembly and generating an output voltage through the DC regulating circuit. The packaging device is disposed on the substrate for covering the regulating circuit and excluding erosion caused by moisture and acidic substances. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and other modifications and advantages will become even more apparent from the following detained description of a preferred embodiment of the invention and from the drawings in which:  
       FIG. 1A  is a top plan view of a conventional DC regulating module;  
       FIG. 1B  is a side view of a conventional DC regulating module;  
       FIG. 2  is a side view of a regulated fuel cell device of this invention; and  
       FIG. 3  is a side view of another embodiment of the regulated fuel cell device of this invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 2  is a side view of a regulated fuel cell device  200  of this invention. The fuel cell device  200  includes a substrate  210 , a DC regulating circuit  220 , a packaging device  230 , a seal  250  and a heat sink  240 . In the regulated fuel cell device  200  of this invention, the DC regulating circuit  220  is directly set on the substrate  210  for receiving a low level DC power generated by the fuel cell device  200  and discharging a steady output voltage, so as to regulate the fuel cell device  200 .  
      The substrate  210  is made of a printed circuit board material and provided with more than one membrane electrode assembly ( 211 ,  212 ). The membrane electrode assembly ( 211 ,  212 ) serves to perform electrochemical reaction for converting chemical energy into a low level DC power.  
      The DC regulating circuit  220  is disposed on the substrate  210  for receiving an input voltage generated by the membrane electrode assemblies ( 211 ,  212 ) and generating an output voltage through the DC regulating circuit  220 . The DC regulating circuit  220  includes a DC regulating integrated circuit  221  and passive units ( 222 ,  223 ) for converting an input voltage power into DC voltage power of various Volt levels. The output voltage may be at a level of +1.8 Volts, +3.3 Volts, +5 Volts and +12 Volts depending on the desired applications.  
      The packaging device  230  is disposed on the substrate  210  and serves to cover the regulating circuit  220  for preventing membrane electrode assemblies ( 211 ,  212 ) from erosion caused by moisture and acidic substances produced by the electro-chemical reaction.  
      To enhance the heat dissipating effect, a seal  250  is injected between the packaging device  230  and the regulating circuit  220 . The seal  250  may be an adhesive with good hear-conductivity containing aluminum oxide injected into the packaging device  230  for encapsulating the DC regulating circuit  220 . By the injection of the seal  250  with good heat-conductivity between the packaging device  230  and the regulating circuit  220 , heat generated by the regulating circuit  220  can be effectively conducted to the packaging device  230 .  
      In this embodiment, the packaging device  230  is made of a metal material, such as aluminum alloy. In other embodiments, the packaging device  230  may be made of a metal or alloy of silver, copper or steel.  
      The heat sink  240  is set on the packaging device  230  for dissipating heat generated by the DC regulating circuit  220 . The heat sink  240  can be fastened onto the packaging device  230  or bonded onto the packaging device  230  by means of an adhesive agent with good heat-conductivity.  
       FIG. 3  is a side view of another embodiment of the regulated fuel cell device  200  of this invention. The feature that differs from that in  FIG. 2  is, instead of the heat sink  240 , a fan  260  is used to improve the heat dissipating capability.  
      It is known from the above description that, as methanol fuel cell not only produces power after chemical reaction, but also generates excessive moisture and a small amount of acidic substance. Accordingly, if an exposed regulating circuit is used in a methanol fuel cell, a permanent damage caused by short circuit from moisture, or erosion of electronic components caused by acidic substances may arise. In view of such properties of the methanol fuel cell, this invention uses an adhesive to package all components of the regulating circuit, so as to insulate from erosion by moisture and acidic substances. At the same time, the fuel cell device is able to output steady DC voltage. Furthermore, through the combination of the DC regulating circuit  220  and the substrate  210  of the fuel cell device  200 , manufacturing cost is reduced. And through the combination of the packaging device  230  and heat sink  240 , heat generated by the DC regulating circuit  220  is dissipated effectively.  
      This invention is related to a novel creation that makes a breakthrough in the art. Aforementioned explanations, however, are directed to the description of preferred embodiments according to this invention. Since this invention is not limited to the specific details described in connection with the preferred embodiments, changes and implementations to certain features of the preferred embodiments without altering the overall basic function of the invention are contemplated within the scope of the appended claims.