Patent Publication Number: US-2007099044-A1

Title: Fuel cartridge monitoring device for fuel cells

Description:
FIELD OF THE INVENTION  
      The present invention relates to a fuel cartridge monitoring device for fuel cells, more particularly a device that integrates electrical circuit, sensor, and logic device to achieve the purpose of supplying fuel of specific concentrations to the fuel cell.  
     BACKGROUND OF THE INVENTION  
      Conventional fuel cell uses hydrogen-rich fuel and undergoes redox reactions to form a current loop for power supply. These types of fuel cell need liquid fuel, such as methanol for reaction. Thus fuel cells typically come with vessel for storing liquid fuel and device for controlling the concentration of fuel. In the age of consumer electronics, the demands for portable power supply escalate dramatically. The industry has been responding by introducing portable fuel cells. But the great majority of fuel cell technologies are inadequate in the area of fuel replenishment. In light of the drawback of conventional fuel cells, a fuel cartridge structure for fuel cells is therefore proposed.  
     SUMMARY OF THE INVENTION  
      The primary object of the present invention is to provide a fuel cartridge monitoring device for fuel cells that can store and supply fuel for fuel cells.  
      Another object of the present invention is to provide a fuel cartridge monitoring device for fuel cells that has a means for mixing fuel and pure water to control the concentration of fuel output.  
      A further object of the present invention is to provide a fuel cartridge monitoring device for fuel cells that has a fluid metering device to control the flow of fluid output.  
      Yet another object of the present invention is to provide a fuel cartridge monitoring device that has a monitoring device to monitor or control the electrical elements of the fuel device.  
      In accordance with the aforesaid objects, the present invention discloses a fuel cartridge monitoring device for fuel cells, comprising: a fuel monitoring device for fuel cells consisting of a fuel solution mixing means, a fluid metering means, and a fluid feeding means; a fuel cartridge for storing high concentration of liquid fuel; a pure water cartridge for storing pure water; a supply cartridge for storing solution mixture of fuel and pure water; opening the fluid feeding means to allow the fluid in fuel cartridge and pure water cartridge to respectively enter the supply cartridge until the solution mixture of fuel and pure water reaches a predetermined level, and then closing the fluid feeding means to stop fluid supply from fuel cartridge and pure water cartridge; a fluid metering means for monitoring the level of fuel solution in the supply cartridge; and when the fluid metering means determines that the fuel solution level falls below a predetermined level, selectively opening the fluid feeding means.  
      The objects, features and advantages of the invention are described in details below with embodiment and accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a diagram showing the structure of a fuel cartridge monitoring device for fuel cells according to one embodiment of the invention;  
       FIG. 2A  is a flow chart showing the control process of the fuel cartridge monitoring device for fuel cells according to one embodiment of the invention;  
       FIG. 2B  is a control flow chart continuing from  FIG. 2A ; and  
       FIG. 3  shows a partial exploded view of a fuel cartridge monitoring device for fuel cells according to another embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 1  is a diagram showing the structure of a fuel cartridge monitoring device for fuel cells according to one embodiment of the invention. The present invention discloses a fuel monitoring device for fuel cell  1  comprising a fuel solution mixing means, a fluid metering means, and a fluid feeding means, which is implemented through the devices as illustrated in  FIG. 1 , including a fuel cartridge  2 , a pure water cartridge  3 , a supply cartridge  4 , a monitoring unit  5 , a liquid level gauge  6 , and a concentration detector  7 .  
      The fuel cartridge  2  is a storage vessel and filled with high concentration of hydrogen rich liquid fuel, e.g. methanol. The fuel cartridge  2  is also equipped with a flow or volume control means for fluid output. Generally, such flow or volume control means can be achieved by a fluid control valve. The pure water cartridge  3  is a storage vessel and filled with pure water, which also comes with a flow or volume control means for fluid output. The supply cartridge  4  is a storage vessel connected to the fuel cartridge  2  and pure water cartridge  3  and selects the amount of fluid entering respectively from fuel cartridge  2  and pure water cartridge  3  through the corresponding flow or volume control means of fuel cartridge  2  and pure water cartridge  3 . The monitoring unit  5  provides a logic decision means and a control means; the logic decision means is for controlling the timing of executing the flow or volume control means of fuel cartridge  2  and pure water cartridge  3 , whereas the control means is for controlling the execution of flow or volume control means of fuel cartridge  2  and pure water cartridge  3 . The liquid level gauge  6  is a device for determining the liquid level in the fuel cartridge  2 , pure water cartridge  3 , and supply cartridge  4 .  
      The supply cartridge  4  is disposed with a concentration detector  7  having the concentration detection means to detect the concentration of fuel in the supply cartridge  4  and transmit such information to monitoring unit  5  for it to determine the fuel concentration in the supply cartridge  4 .  
       FIG. 2A  and  FIG. 2B  illustrate the control flow chart of the fuel cartridge monitoring device for fuel cells according to an embodiment of the invention. As shown in  FIG. 2 , the control flow process includes: step  101  where fuel cartridge  2  stores high concentration of liquid fuel, e.g. methanol; step  102  where pure water cartridge stores pure water; step  103  where the monitoring unit  5  opens respectively the fluid control valve of fuel cartridge  2  and pure water cartridge  3 , determines the amount of fluid entering supply cartridge  4  from fuel cartridge  2  and pure water cartridge  3  through its logic decision means, and closes respectively the fluid control valve of fuel cartridge  2  and pure water cartridge  3  through its control means when the amount of fluid in the supply cartridge  4  reaches a predetermined level to achieve the fuel solution mixing means; step  104  where the monitoring unit  5  continues to monitor the level of solution mixture of fuel and pure water in the supply cartridge  4  through liquid level gauge  6 ; step  105  where the monitoring unit  5  controls the output of fuel from supply cartridge  4  to fluid feeding means according to the demands of fuel cell  1 ; and step  106  where the monitoring unit  5  monitors the fuel solution level in supply cartridge  4  through a liquid level gauge  6  to achieve the fluid metering means, and when the fuel solution level falls below the predetermined liquid level, the monitoring unit  5  selectively enters step  103 .  
      In the aforesaid steps, the concentration of fuel solution is controlled by controlling the amount of fluid entering the supply cartridge  4  from fuel cartridge  2  and pure water cartridge  3  respectively, and the fluids from fuel cartridge  2  and pure water cartridge  3  could also enter a temporary storage area for full mixing before entering the supply cartridge  4 .  
      Furthermore, the aforesaid fluid control valve can be a simple fluid switch control valve for selecting the opening or closing of fluid output from fuel cartridge  2  and pure water cartridge  3 . However, the monitoring unit  5  could monitor the reduction of liquid level gauge  6  in fuel cartridge  2  and pure water cartridge  3  respectively to determine the output from fuel cartridge  2  and pure water cartridge  3  so as to determine whether the fluids entering supply cartridge  4  from fuel cartridge  2  and pure water cartridge  3  have reached the predetermined level.  
      A step  107  may be further added, where the monitoring unit  5  continues to monitor the concentration of fuel solution in supply cartridge  4  through a concentration detector  7 . When the monitoring unit  5  determines through concentration detector  7  that the concentration of fuel solution in supply cartridge  4  falls below a predetermined level, it determines the amount of fuel needed from the fuel cartridge  2  through its logic decision means and selectively opens the fluid control valve of fuel cartridge  2  until the fuel cartridge  2  has fed the supply cartridge  4  a predetermined amount of fuel, and upon which, closes the fluid control valve of fuel cartridge  2  through its control means, thereby regulating the concentration of fuel solution in supply cartridge  4  to the desired level.  
       FIG. 3  shows a partial exploded view of a fuel cartridge monitoring device for fuel cells according to another embodiment of the invention. The fuel cartridge  2 , pure water cartridge  3  and supply cartridge  4  (as shown in  FIG. 1 ) of the fuel cartridge monitoring device herein have respectively fluid storage space, fluid inlet, and fluid outlet. In the example of the supply cartridge  4  of a methanol fuel cell that supplies specific concentration of methanol as shown in  FIG. 3 , the supply cartridge  4  comes with a plurality of inlets  41  and an outlet  42 . The inlets  41  are respectively connected to the fuel cartridge  2  and pure water cartridge  3 , while the outlet  42  is connected to the fuel cell  1 , and the inlets  41  and outlet  42  have typical fluid circulation control structure, such as a valve that allows inlets  41  and outlet  42  to selectively circulate and seal the fluid. The monitoring unit  5  consists of a first local circuit  51  arranged on the exterior surface of supply cartridge  4  to control the inlets  41  and outlet  42  of supply cartridge  4  and monitor the liquid level gauge  6 . The control flow process of the invention may be effected according to the embodiment just cited.  
      The monitoring unit  5  may further contain a second local circuit  52  and a third local circuit  53 ; the second local circuit  52  is disposed on the exterior surface of fuel cartridge  2  to monitor or control the electrical elements configured therein, and the third local circuit  53  is disposed on the exterior surface of pure water cartridge  3  to monitor or control the electrical elements configured therein.  
      In addition, the embodiments cited above may achieve metering means through inlets and outlet having flow control means without the use of a liquid level gauge.  
      According to the aforesaid embodiments, the supply cartridge  4  may be arranged with a concentration detector  7  having concentration detection means to detect the concentration of fuel in the fuel cartridge  4 , and transmit such information to the monitoring unit  5  for it to determine the fuel concentration in the supply cartridge  4 .  
      According to the aforesaid embodiments, the supply cartridge  4  may be configured with a first transmission port  43  which integrates the first local circuit  51  of monitoring unit  5  to allow the monitoring unit  5  to export through it information relating to the supply cartridge  4 , including the height of fuel solution, the amount of fuel solution, or the concentration of fuel solution to an external system. For example, the first transmission port  43  can have a USB interface,  1394  interface, or any transmission interface used for data output by an electronic device, and the monitoring unit  5  can transfer the information on the concentration of fuel in supply cartridge  4  to a personal computer. Further, the fuel cartridge  2  and pure water cartridge  3  can have respectively a second transmission port  21  and a third transmission port  31 , which respectively integrates the second local circuit  52  and the third local circuit  53  of monitoring unit  5  to allow the monitoring unit  5  to export through the second local circuit  52  and third local circuit  53  respectively information relating to fuel cartridge  2  and pure water cartridge  3  to an external system.  
      In the aforesaid embodiments, the first local circuit  51 , second local circuit  52 , and third local circuit  53  of monitoring unit  5  may be operated independently. Thus the fuel cartridge  2 , pure water cartridge  3 , and supply cartridge  4  may be independent units, where the supply cartridge  4  connects to fuel cartridge  2  and pure water cartridge  3  respectively through the inlet  41 . Further, synergistic operation of the fuel cartridge  2 , pure water cartridge  3 , and supply cartridge  4  may be achieved by integrating the first local circuit  51 , second local circuit  52  and third local circuit  53  through the monitoring unit  5 .  
      In the aforesaid embodiments, the liquid level gauge  6  may have the means to display directly the liquid level to allow user to determine whether the fluid in fuel cartridge  2 , pure water cartridge  3 , or supply cartridge  4  is depleted.  
      A few embodiments of the invention have been disclosed, which however should not be construed as a limitation on the scope of claim. All modifications and alterations to the descriptions disclosed made by those familiar with the skill without departing from the spirits of the invention and appended claims shall remain within the protected scope and claims of the invention.