Abstract:
Provided is a fuel cell system including: a cartridge in which fuel is stored; a power unit producing power by using the fuel supplied from the cartridge; and a port to which an electronic device is connected, wherein the port comprises: a first channel which is a channel for receiving start-up power from the electronic device and supplying produced power to the electronic device; a second channel via which a signal indicating attachment of the fuel cell system to the electronic device is transmitted to the electronic device when the fuel cell system is attached to the electronic device; and a third channel for grounding.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
     This application claims the benefit of Korean Patent Application No. 10-2008-0001425, filed on Jan. 4, 2008 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a fuel cell system and a method of operating the same. 
     2. Description of the Related Art 
     Secondary electric cells, that is, batteries, are widely used as power supply sources for laptop computers, personal digital assistants (PDAs), portable display devices, mobile phones, etc. 
     As the variety of portable electronic devices increases, various batteries for each kind of electronic device are being introduced. 
     However, the batteries currently used for portable electronic devices do not provide power for as long as the user desires. In particular, when the portable electronic devices are operated continuously, the time the batteries can be used may further decrease. Also, in the case of currently used batteries, it takes a lot of time to completely charge the batteries, and the performance of the batteries may be degraded as the batteries are charged and discharged frequently. 
     Accordingly, new power sources have been developed, and one of these is a fuel cell system. 
     A fuel cell system can be formed of a cartridge, in which fuel such as methanol is stored, and a power unit produces power by using the fuel supplied from the cartridge. 
     The fuel cell system can produce power continuously as long as fuel is supplied. Thus power can be produced as long as the user wants. Also, if the fuel runs out, power can be produced again by replacing the cartridge or supplying fuel to the cartridge. Accordingly, in the fuel cell system, the time required for producing power again is significantly shorter than a charging time of a battery. 
     SUMMARY OF THE INVENTION 
     The present invention provides a fuel cell system capable of supplying start-up power from the outside. 
     The present invention also provides a method of operating the fuel cell system. 
     According to an aspect of the present invention, there is provided a fuel cell system comprising: a cartridge in which fuel is stored; a power unit producing power by using the fuel supplied from the cartridge; and a port to which an electronic device is connected, wherein the port comprises: a first channel which is a channel for receiving start-up power from the electronic device and supplying produced power to the electronic device; a second channel via which a signal indicating attachment of the fuel cell system to the electronic device is transmitted to the electronic device when the fuel cell system is attached to the electronic device; and a third channel for grounding. 
     The power unit may comprise a system control unit, a balance of plant (BOP) and a driver, a fuel cell, and a direct current-direct current (DC-DC) converter. The fuel cell system may further comprise a short prevention unit between the DC-DC converter and the first channel. The port may be protruded from or is recessed into a surface of a case of the fuel cell system. A coupling unit for coupling the fuel cell system to the electronic device may be formed around the port. 
     According to another aspect of the present invention, there is provided a method of operating the fuel cell system comprising: a cartridge in which fuel is stored; a power unit producing power by using the fuel supplied from the cartridge; and a port to which an electronic device is connected, wherein the port comprises: a first channel which is a channel for receiving start-up power from the electronic device and supplying produced power to the electronic device; a second channel via which a signal indicating attachment of the fuel cell system to the electronic device is transmitted to the electronic device when the fuel cell system is attached to the electronic device; and a third channel for grounding, the method comprising: informing the electronic device through the second channel that the fuel cell system is connected to the electronic device; receiving start-up power from the electronic device through the first channel; and driving the fuel cell system using the supplied start-up power. 
     The driving of the fuel cell system using the supplied start-up power may comprise applying a driving signal to the BOP and the driver using the supplied start-up power. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: 
         FIG. 1  is a schematic plan view of a fuel cell system according to an embodiment of the present invention; 
         FIG. 2  is a detailed plan view of the fuel cell system of  FIG. 1 ; and 
         FIG. 3  is a flowchart showing a method of operating the fuel cell system of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Detailed example embodiments are disclosed herein. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. Example embodiments may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein. 
     Accordingly, while example embodiments are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but to the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of example embodiments. Like numbers refer to like elements throughout the description of the figures. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it may be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.). 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising,” “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. 
     Example embodiments will now be described more fully with reference to the accompanying drawings. In the drawings, the thicknesses of layers and regions may be exaggerated for clarity. 
     A fuel cell system according to at least one embodiment of the present invention will be described with reference to  FIG. 1 . 
       FIG. 1  illustrates a fuel cell system  40  according to an embodiment of the present invention. 
     Referring to  FIG. 1 , the fuel cell system  40  includes a cartridge  42 , a power unit  44 , and a port  48  providing a power interface. Fuel to be supplied to the power unit  44  is stored in the cartridge  42 . The fuel is used to supply oxygen to an anode of a fuel cell included in the power unit  44 . For example, the fuel may be methanol. When the fuel is methanol, the density of the methanol may be adjusted. The cartridge  42  may be a pressurization type or a non-pressurization type. Also, in order to be coupled to each other, the cartridge  42  and the power unit  44  include a coupling unit for coupling, respectively. 
     According to another embodiment of the present invention, the cartridge  42  may be permanently connected to the power unit  44 , and a fuel inlet hole may be formed in another portion of the cartridge  42 . Fuel can be filled into the cartridge  42  through the fuel inlet hole. 
     The power unit  44  includes the fuel cell that produces power by using fuel supplied from the cartridge  42 . The power unit  44  may include a fuel transferring line transferring fuel to the fuel cell from the cartridge  42 , for example, a balance of plant (BOP) and a driver. Also, the power unit  44  may generate a control signal controlling the amount of fuel supplied to the fuel cell according to the state of the fuel cell. Also, when the fuel cell system  40  is connected to a load, a fuel cell managing unit, that is, a system control unit, generating a signal (hereinafter, a first signal), may be formed in the power unit  44  in order to inform the power unit  44  that the fuel cell system  40  is connected to the load. Also, the power unit  44  may include a power matching unit that matches the level of the power output from the fuel cell to a power level appropriate for the load. An example of the power matching unit may be a direct current-direct current (DC-DC) converter. The load may be one of various portable electronic devices such as a laptop computer, a personal digital assistant (PDA), a portable display device, etc. The port  48  may include first through third channels c 1  to c 3 . Power generated by the power unit  44  is supplied to the load through the first channel c 1 . Also, power for starting up the fuel cell system is supplied from the load to the power unit  44  through the first channel c 1 . The first signal is transmitted to the load through the second channel c 2 . The third channel c 3  is a power grounding channel. When the fuel cell system  40  is connected to the load, the third channel c 3  can be connected to a grounding terminal at the load. The arrangement of the first through third channels c 1  to c 3  in the port  48  may vary. For example, the channels may be arranged in the order of the first, third, and second channels c 1 , c 3 , and c 2 . 
       FIG. 2  illustrates the fuel cell system  40  having the structure of  FIG. 1 , according to an embodiment of the present invention. 
     Referring to  FIG. 2 , the power unit  44  includes a system control unit  44   a , a balance of plant (BOP) and a driver  44   b , a fuel cell  44   c , and a DC-DC converter  44   d . The fuel cell  44   c  may be a stack type or a planar type. 
     Hereinafter, the operation of the fuel cell system  40  of  FIG. 2  will be described. 
     When the fuel cell system  40  is connected to a load  80 , a first signal s 1  is transmitted from the system control unit  44   a  to the load  80  through the second channel c 2 . The load  80  can recognize through the first signal s 1  that the fuel cell system  40  is connected to the load  80 . The first signal s 1  may be an electric signal, for example, a pulse signal, which is generated as the second channel c 2  is connected to a corresponding portion of the load  80  or as the second channel c 2  is physically or mechanically attached to the load  80 . When the load  80  has recognized that the fuel cell system  40  is connected thereto, the load  80  applies start-up power to the system control unit  44   a  through the first channel c 1  for a predetermined period of time. The time for applying start-up power may vary according to the state of power source included in the load  80 . For example, when the power source of the load  80  is sufficient to supply the start-up power, the load  80  can supply start-up power to the fuel cell system  40  until power needed for driving the load  80  is produced in the fuel cell system  40 . 
     When the start-up power is applied to the system control unit  44   a , the system control unit  44   a  applies a second signal s 2  to the BOP and the driver  44   b  using the start-up power. The second signal s 2  is a driving control signal. The BOP and the driver  44   b  are driven by the second signal s 2  and thus fuel and air are supplied to the fuel cell  44   c . Thus, power is produced due to a chemical reaction in the fuel cell  44   c , and the produced power (V FC ) is transferred to the DC-DC converter  44   d . The DC-DC converter supplies the transferred power (V FC ) to the load  80  through the first channel c 1 . 
     Meanwhile, a third signal s 3  which has information on the amount of fuel contained in the cartridge  42  may be transmitted to the system control unit  44   a  continuously in real time or periodically. The system control unit  44   a  applies the second signal s 2  to the BOP and the driver  44   b  based on the information obtained through the third signal s 3 , thereby controlling the amount of fuel supplied from the BOP and the driver  44   b  to the fuel cell  44   c.    
     As described above, the operation of the fuel cell system starts from the start-up power supplied from the load  80 , and thus the fuel cell system does not have to include an additional power source for the starting up operation, for example, a conventional lithium ion battery. Accordingly, the volume and weight of the fuel cell system according to at least one embodiment of the present invention can be reduced. 
     The operation of the above-described fuel cell system of  FIG. 2  may be included in the operation method of the fuel cell system as illustrated in  FIG. 3 . 
     Referring to  FIG. 3 , the method of operating the fuel cell system  40  according to at least one embodiment of the present invention includes receiving start-up power from the outside (operation  100 ), driving the fuel cell system by using the supplied start-up power (operation  200 ), and supplying power to the outside (operation  300 ). 
     In operation  100 , start-up power is supplied from the load  80 , to which the fuel cell system  40  is connected, to the system control unit  44   a . The time for supplying start-up power may vary according to the state of the basic battery connected to the load  80 , as described above. A signal informing that the fuel cell system  40  is connected may be applied to the load  80  before operation  100 . The start-up power may be applied thereafter. 
     In operation  200 , the BOP and the driver  44   b  are driven using the start-up power, thereby supplying fuel and air to the fuel cell  44   c  including a plurality of unit cells. 
     In operation  300 , power is produced in the fuel cell  44   c , and the produced power is supplied to the load  80  through the DC-DC converter  44   d  and the first channel c 1 . 
     During the operation of the fuel cell system  40 , the system control unit  44   a  checks the amount of remaining fuel contained in the cartridge  42  and checks the condition of the fuel cell  44   c , for example, the temperature of the fuel cell  44   c , the output power of the fuel cell  44   c , etc., and thus can control the operation of the fuel cell system  40  according to the result of checking the condition. 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, the exemplary embodiments should be considered in a descriptive sense only and not for purposes of limitation. For example, it will be understood by those of ordinary skill in the art that the shape or the coupling form of the port  48  may be changed from that described in relation to  FIG. 2 , while maintaining the structure of the port  48 . For example, the port  48  may be formed to simply contact the load  80 , and an additional coupling unit may be formed around the port  48 . Also, a short circuit prevention unit may be formed between the first channel c 1  and the DC-DC converter  44   d . In addition, the port  48  may be protruded from or recessed into a surface of a case of the fuel cell system. Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims.