Abstract:
A system for adsorbing a thin film sheet includes a main frame and first and second auxiliary frames connected to respective ends of the main frame. At least one of the first and second auxiliary frames is movably connected to the main frame to increase or decrease a distance between the first and second auxiliary frames. Adsorbing parts are disposed under the first and second auxiliary frames, respectively, to draw or inject air and to adsorb both sides of the thin film sheet. A tension adjusting part adjusts a location of the at least one of the first and second auxiliary frames to adjust a tension applied to the thin film sheet.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of priority to Korean Patent Application No. 10-201 5-0071079 filed in the Korean Intellectual Property Office on May 21, 2015, the entire content of which is incorporated herein by reference. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates to a system for adsorbing a thin film sheet in a fuel cell system, which capable of adsorbing both sides of the thin film sheet, in which a membrane-electrode assembly (MEA) is combined with a gas diffusion layer (GDL) to prevent a center portion of the thin film sheet from drooping. 
       BACKGROUND 
       [0003]    In general, a fuel cell system is a power generating system which electrochemically converts chemical energy of fuel into electrical energy within a fuel cell stack without changing the chemical energy into heat by combustion. 
         [0004]    The fuel cell system generally includes the fuel cell stack generating the electrical energy and a fuel supply system supplying a fuel (hydrogen) to the fuel cell stack. An air supply system supplies oxygen in air, which is an oxidizing agent necessary for an electrochemical reaction, to the fuel cell stack. A heat/water management system removes heat of the fuel cell stack to outside and controls an operation temperature of the fuel cell stack. 
         [0005]    Through the aforementioned configuration, the fuel cell system generates electricity by the electrochemical reaction between hydrogen that is the fuel and oxygen in the air, and discharges the heat and water as reaction by-products. 
         [0006]    A fuel cell system for a vehicle, which is an energy converting apparatus formed of a membrane-electrode assembly (hereinafter referred to as an “MEA”), comprises an electrode/catalyst layer attached to both sides of an electrolyte membrane for generating an electrochemical reaction. As hydrogen ions move, a gas diffusion layer (hereinafter referred to as a “GDL”) evenly distributes reaction gas and transmits generated electricity and a gasket and a fastening mechanism maintains a sealing property and an appropriate fastening pressure of the reaction gas and a coolant. A separator, in which the reaction gas and the coolant move, generates a current by a cell reaction when hydrogen and oxygen (air) are injected. 
         [0007]    In a polymer solid electrolyte fuel cell, hydrogen is supplied to a positive electrode (also referred to as a “fuel electrode”), and oxygen (air) is supplied to a negative electrode (also referred to as an “air electrode” or an “oxygen electrode”). 
         [0008]    The hydrogen supplied to the positive electrode is dissolved into hydrogen ions (protons, H+) and electrons (e−) by a catalyst of the electrode layer formed on both sides of the electrolyte membrane, and among them, only the hydrogen ions (protons, H+) selectively pass through the electrolyte membrane that is a positive ion exchange membrane and are transmitted to the negative electrode, and simultaneously, the electrons (e−) are transmitted to the negative electrode through the GDL that is a conductor and the separator. 
         [0009]    A reaction occurs in the negative electrode in which the hydrogen ions supplied through the electrolyte membrane and the electrons transmitted through the separator react with the oxygen supplied to the negative electrode to generate water. 
         [0010]    A current is generated by the electrons flowing through an external conductive wire as the hydrogen ions move, and heat is also generated in the water generation reaction. 
         [0011]    In order to manufacture a fuel cell, a loading/unloading system for adsorbing a thin film sheet of a combination of the MEA and the GDL and moving the adsorbed thin film sheet has been applied. 
         [0012]    An adsorption part adsorbs both upper sides of the thin film sheet for the fuel cell. A center portion of the thin film sheet, which is not adsorbed during a loading/unloading process, may droop to a lower side by gravity. Due to the drooping phenomenon, the entire thin film sheet may be separated or fall from the adsorption part to degrade quality of the fuel cell and production efficiency. 
         [0013]    The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
       SUMMARY 
       [0014]    The present disclosure has been made in an effort to provide a system for adsorbing a thin film sheet (a membrane-electrode assembly (MEA)+a gas diffusion layer (GDL)) from drooping, which adsorbs the thin film sheet and prevents the thin film sheet from drooping, thereby improving quality of a fuel cell. 
         [0015]    According to an exemplary embodiment of the present inventive concept, a system for adsorbing a thin film sheet includes a main frame and first and second auxiliary frames connected to respective sides of the main frame. At least one of the first and second auxiliary frames is movably connected to the main frame to increase or decrease a distance between the first and second auxiliary frames. Adsorbing parts are disposed under the first and second auxiliary frames, respectively, to draw or inject air and to adsorb both sides of the thin film sheet. A tension adjusting part adjusts a location of the at least one of the first and second auxiliary frames in the main frame to adjust a tension applied to the thin film sheet. 
         [0016]    The tension adjusting part may include a tension applying cylinder pushing or pulling the at least one of the first and second auxiliary frames toward or from the main frame. 
         [0017]    The tension adjusting part may further include a fixing brake limiting movement of the at least one of the first and second auxiliary frames by the tension applying cylinder. 
         [0018]    The thin film sheet may include a membrane-electrode assembly (MEA), and a gas diffusion layer (GDL) attached to a center portion of one surface of the MEA. 
         [0019]    The adsorbing parts may include MEA adsorbing parts disposed under the first and second auxiliary frames and adsorbing the MEA. GDL adsorbing parts are disposed at one side of the MEA adsorbing parts under the first and second auxiliary frame and adsorbing the GDL. 
         [0020]    The system may further include a vertically moving part vertically moving the MEA adsorbing parts and the GDL adsorbing parts. 
         [0021]    One of the first and second auxiliary frames may be fixed to the main frame, and the other may be movably connected to the main frame in a longitudinal direction. The system may further include a proximity sensor mounted on the main frame to detect an approach of the thin film sheet adsorbed by the adsorbing parts. 
         [0022]    The system may further include an ultrasonic sensor mounted on the main frame to detect a thickness of the thin film sheet or the number of thin film sheets adsorbed by the adsorbing parts. 
         [0023]    The GDL adsorbing part may include a suctioning gripper sucking air and adsorbing the thin film sheet. 
         [0024]    The MEA adsorbing parts may include a porous pad which is in contact with one surface of the thin film sheet. 
         [0025]    The at least one of the first and second auxiliary frames may move on a rail which is attached to the main frame. 
         [0026]    According to another exemplary embodiment of the present inventive concept, a method of adsorbing a thin film sheet includes moving a main frame toward the thin film sheet. Both sides of the thin film sheet are adsorbed through adsorbing parts attached to first and second auxiliary frames, which movably connected to both sides of the main frame, respectively. A tension applied to the thin film sheet is adjusted by adjusting a distance between the first and second auxiliary frames through a tension adjusting part. The method may further include applying the tension to the thin film sheet such that the tension is maintained by limiting movement of at least one of the first and second auxiliary frames using a fixing brake. 
         [0027]    The method may further include detecting an approach of the thin film sheet, which is to be adsorbed to the adsorbing part, through a proximity sensor. 
         [0028]    The method may further include detecting a thickness of the thin film sheet or the number of thin film sheets adsorbed to the adsorbing part through an ultrasonic sensor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]      FIG. 1  is a perspective view of a system for adsorbing a thin film sheet from according to an exemplary embodiment of the present inventive concept. 
           [0030]      FIG. 2  is a schematic configuration diagram of the system for adsorbing a thin film sheet according to the exemplary embodiment of the present inventive concept. 
           [0031]      FIG. 3  is a flowchart illustrating a method of adsorbing a thin film sheet using the system for adsorbing a thin film sheet according to an exemplary embodiment of the present inventive concept. 
           [0032]      FIG. 4  is a front view of the system for adsorbing a thin film sheet according to the exemplary embodiment of the present inventive concept. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0033]    An exemplary embodiment of the present inventive concept will hereinafter be described in detail with reference to the accompanying drawings. 
         [0034]      FIG. 1  is a perspective view of a system for adsorbing a thin film sheet according to an exemplary embodiment of the present inventive concept. 
         [0035]    Referring to  FIG. 1 , a thin film sheet adsorbing system includes a tension applying cylinder  100 , a fixing brake  110 , a main frame  120 , an ultrasonic sensor  130 , a vertically moving part  180 , a porous pad  190 , a membrane-electrode assembly (MEA) adsorbing part  135 , a first auxiliary frame  140 , an MEA  145 , a gas diffusion layer (GDL)  150 , a GDL adsorbing part  155 , a proximity sensor  160 , and a second auxiliary frame  165 . 
         [0036]    The first and second auxiliary frames  140  and  165  are disposed at both sides of the main frame  120  in a longitudinal direction of the main frame  120 , respectively. At least one of the first and second auxiliary frames  140  and  165  is connected so as to reciprocate in the longitudinal direction of the main frame  120  based on the main frame  120 . 
         [0037]    Further, the tension applying cylinder  100  is provided on an upper surface of the main frame  120 . The tension applying cylinder  100  pushes or pulls at least one of the first and second auxiliary frames  140  and  165 . 
         [0038]    The MEA adsorbing part  135  and the GDL adsorbing part  155  are spaced apart from each other and located at lower sides of the first and second auxiliary frames  140  and  165 , respectively. The MEA adsorbing part  135  includes a suctioning gripper  170  suctioning air and adsorbing one surface of the MEA  145 . The GDL adsorbing part  155  may include both a Bernoulli gripper injecting air and floating the GDL  150  to the air, and the suctioning griper  170  suctioning air and adsorbing the GDL  150 . 
         [0039]    The MEA adsorbing part  135  and the GDL adsorbing part  155  are located below the first and second auxiliary frames  140  and  165 , respectively, and vertically move based on the first and second auxiliary frames  140  and  165 . The vertically moving part  180  may vertically move the MEA adsorbing part  135  and the GDL adsorbing part  15  using hydraulic pressure (pneumatic pressure). 
         [0040]    Under the main frame  120 , the second auxiliary frame  165  slides along a guide rail  400  (see  FIG. 4 ). The second auxiliary frame  165  moves based on the main frame  120  by the tension applying cylinder  100 . 
         [0041]    Then, the fixing brake  110  may apply a frictional force to the second auxiliary frame  165  to limit the movement of the second auxiliary frame  165 . 
         [0042]    The ultrasonic sensor  130  and the proximity sensor  160  are mounted to an upper side or a lower side of the main frame  120 . The proximity sensor  160  detects an approach of the GDL  150  or the MEA  145  when the main frame  120  moves. 
         [0043]    Further, the ultrasonic sensor  130  irradiates ultrasonic waves to the GDL  150  or the MEA  145  facing the main frame  120  to detect a thickness of the GDL  150  or the MEA  145  and detect the number of sheets according to the thickness. 
         [0044]      FIG. 2  is a schematic configuration diagram of the system for adsorbing a thin film sheet according to the exemplary embodiment of the present inventive concept. 
         [0045]    Referring to  FIG. 2 , the ultrasonic sensor  130 , the proximity sensor  160 , the tension applying cylinder  100 , and the fixing brake  110  are disposed in the main frame  120 , and a signal detected by the ultrasonic sensor  130  and the proximity sensor  160  is transmitted to a controller  200 . Further, the controller  200  may control the tension applying cylinder  100  and the fixing brake  110 . 
         [0046]    That is, the controller  200  may control the hydraulic pressure (pneumatic pressure) applied to the tension applying cylinder  100  to operate the tension applying cylinder  100 , and forms a frictional force through the fixing brake  110  to limit the movement of the second auxiliary frame  165 . 
         [0047]    The MEA adsorbing part  135  and the GDL adsorbing part  155  vertically movably connected to lower sides of the first and second auxiliary frames  140  and  165 . The vertically moving part  180  vertically moves the MEA adsorbing part  135  and the GDL adsorbing part  155  using the supplied hydraulic pressure (pneumatic pressure). 
         [0048]    The controller  200  may control the MEA adsorbing part  135 , the GDL adsorbing part  155 , and the vertically moving part  180 . 
         [0049]    That is, the controller  200  may allow the MEA adsorbing part  135  and the GDL adsorbing part  155  draw or inject air by operating a vacuum pump (not illustrated) or a blower (not illustrated) to adsorb the MEA  145  and the GDL  150 . Further, the controller  200  may control heights of the MEA adsorbing part  135  and the GDL adsorbing part  155  by operating the vertically moving part  180  by controlling the hydraulic pressure (pneumatic pressure). 
         [0050]    The controller  200  may be implemented by one or more micro-processors operated by a predetermined program, and the predetermined program may include a series of commands for performing a method according to the present disclosure to be described below. 
         [0051]      FIG. 3  is a flowchart illustrating a method of adsorbing a thin film sheet using the system for adsorbing a thin film sheet according to an exemplary embodiment of the present inventive concept. 
         [0052]    Referring to  FIG. 3 , a robot arm  300  moves the main frame  120  to a predetermined location in S 300 . The main frame  120  approaches a thin film sheet  152 , in which the GDL is bonded to the MEA  145 , in S 310 . The approach of the main frame  120  to the thin film sheet  152  may be detected by the proximity sensor  160 . 
         [0053]    In S 320 , the MEA adsorbing part  135  and the GDL adsorbing part  155  suck or inject air to form vacuum, thereby adsorbing the MEA  145  and the GDL  150 , respectively. 
         [0054]    In the present disclosure, the MEA adsorbing part  135  may include an suctioning gripper  170  which extracts air and adsorbs the MEA  145 . The porous pad  190 , which is in contact with the MEA  145 , may be disposed in the MEA adsorbing part  135 . 
         [0055]    Further, the GDL adsorbing part  155  may include a Bernoulli gripper which injects air and floats the GDL  150 , and the suctioning griper which inhales the air and adsorbs the floated GDL  150 . 
         [0056]    In S 330 , a thickness of the adsorbed thin film sheet (the MEA+the GDL) or the number of thin film sheets is detected through the ultrasonic sensor  130 . In S 340 , the second auxiliary frame  165  moves to an external side based on the main frame  120  by controlling hydraulic pressure (pneumatic pressure) supplied to the tension applying cylinder  100 , so that the MEA adsorbing part  135  and the GDL adsorbing part  155  pull both sides of the thin film sheet  152 . 
         [0057]    In S 350 , the fixing brake  110  operates to limit a movement of the second auxiliary frame  165 . Then, in S 360 , the robot arm  300  moves the main frame  120  to move the thin film sheet  152  to a predetermined location, stops the operation of the adsorbing part, and unloads the thin film sheet  152  to a predetermined location. 
         [0058]    Accordingly, in the present disclosure, tension is applied to the thin film sheet  152 , so that it is possible to effectively prevent a center portion, which is not adsorbed, from drooping to a lower side, and prevent the thin film sheet from being separated from the adsorbing part due to the drooping. 
         [0059]      FIG. 4  is a front view of the system for adsorbing a thin film sheet according to the exemplary embodiment of the present inventive concept, and descriptions of similar or identical parts to those of  FIG. 1  will be omitted, and differences will be mainly described. 
         [0060]    Referring to  FIG. 4 , the first and second auxiliary frames  140  and  165  are disposed at lower surfaces of both ends of the main frame  120 , and the main frame  120  and the first and second auxiliary frames  140  and  165  are parallel to each other. 
         [0061]    An upper surface of one end of the first auxiliary frame  140  may be fixed to the main frame  120  through a bracket  405 , and the second auxiliary frame  165  may be movably connected to the main frame  120  through the rail  400 . 
         [0062]    Accordingly, in the system for adsorbing a thin film sheet according to the exemplary embodiment of the present inventive concept, the tension applying cylinder  100  controls tension applied to the thin film sheet  152  by moving the GDS adsorbing part  155  and the MEA adsorbing part  135  in a state where the GDL adsorbing part  155  and the MEA adsorbing part  135  adsorb both sides of the thin film sheet  152 , respectively, so that it is possible to easily prevent the center portion of the thin film sheet  152  from drooping to the lower side. 
         [0063]    While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.