Abstract:
Provided is an end cell heater for a fuel cell capable of preventing water existing in reaction cells of a fuel cell stack from being frozen to improve initial start ability and initial driving performance of the fuel cell at the time of cold-starting the fuel cell during winter by disposing heaters on end cells disposed at both ends of the fuel cell stack and capable of securing air-tightness and pressure resistance properties of air passages and fuel passages formed in the end cell.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under 35 U.S.C. §119 to Korean Patent Application No. 10-2016-0089794, filed on Jul. 15, 2016, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. 
       TECHNICAL FIELD 
       [0002]    The following disclosure relates to an end cell heater for a fuel cell. More particularly, the following disclosure relates to an end cell heater for a fuel cell capable of preventing water existing in reaction cells of a fuel cell stack from being frozen to improve initial start ability and initial driving performance of the fuel cell at the time of cold-starting the fuel cell during winter by disposing heaters on end cells disposed at both ends of the fuel cell stack. 
       BACKGROUND 
       [0003]    Generally, a fuel cell, which is a power generation device converting chemical energy by oxidation and reduction of hydrogen into electric energy, discharges only water (H 2 O) as a byproduct, does not substantially generate NOx, SOx, and dust, generates a low amount of CO 2 , and does not substantially generate noise unlike existing other chemical energy. Therefore, the fuel cell has been prominent as the next-generation alternative energy. 
         [0004]    The fuel cell includes unit cells basically including an electrolyte plate containing an electrolyte, an anode, a cathode, and a separator separating the electrolyte plate containing the electrolyte, the anode, and the cathode from one another. However, since the unit cell generally generates a low voltage of 0.6 to 0.8V, a fuel cell stack  1  in which several tens or several hundreds of unit cells  30  are stacked is configured to obtain a desired electric output, as illustrated in  FIG. 1 . In addition, a membrane-electrode assembly (MEA) is configured by forming the electrolyte plate containing the electrolyte, the anode, and the cathode integrally with one another, and patterns are formed in the separator separating the electrolyte plate containing the electrolyte, the anode, and the cathode from one another to allow a fuel and air to flow. 
         [0005]    In addition, various fuels such as natural gas, petroleum, coal gas, methanol, and the like, may be used in the fuel cell, and are converted into hydrogen through a fuel reforming device and are used. 
         [0006]    However, in the fuel cell configured in a form of the fuel cell stack as described above, water generated by bond between oxygen and hydrogen in unit cells (end cells) positioned at the outermost portions in a stack direction of the unit cells remains, and is frozen in the end cells due to a cold external temperature during winter. Therefore, electricity is not generated in the end cells, such that initial start ability and oscillation ability of the fuel cell are deteriorated. 
       RELATED ART DOCUMENT 
     Patent Document 
       [0007]    KR 10-1466507 B1 (Nov. 21, 2014) 
       SUMMARY 
       [0008]    An embodiment of the present invention is directed to providing an end cell heater for a fuel cell capable of preventing water existing in reaction cells of a fuel cell stack from being frozen by disposing heaters on end cells disposed at both ends of the fuel cell stack. 
         [0009]    An embodiment of the present invention is also directed to providing an end cell heater capable of securing air-tightness and a pressure resistance property of an air passage and a fuel passage formed in an end cell. 
         [0010]    In one general aspect, an end cell heater  1000  for a fuel cell includes: an end cell  100  including a body  110  and an upper cover  120  stacked on and in contact with an upper surface of the body  110 , and having air channels  111  formed between the body  110  and the upper cover  120 ; a heating element  200  stacked on and coupled to the end cell  100 ; and an electricity collecting plate  300  stacked on and in contact with the heating element  200 . 
         [0011]    Fusing protrusions may be formed to protrude on any one or more of the upper surface of the body  110  and a lower surface of the upper cover  120 , fusing grooves may be concavely formed at both sides of the fusing protrusions so as to be in contact with the fusing protrusions, and the fusing protrusions may be melted, such that the body  110  and the upper cover  120  are bonded to each other. 
         [0012]    The fusing protrusions and the fusing grooves may be formed at both sides of the air channels  111  so as to be spaced apart from the air channels  111 . 
         [0013]    In the end cell  100 , fusing protrusions may be melted by vibration fusion or laser fusion, such that the body  110  and the upper cover  120  are bonded to and formed integrally with each other. 
         [0014]    A seating groove may be concavely formed in a lower surface of the body  110 , and the electricity collecting plate  300  may be stacked on a lower surface of the heating element  200  so as to be in contact with the lower surface of the heating element  200 , such that the heating element  200  and the electricity collecting plate  300  are inserted into and seated in the seating groove. 
         [0015]    In another general aspect, an end cell heater  1000  for a fuel cell includes: an end cell  100  including a body  110 , an upper cover  120  stacked on and in contact with an upper surface of the body  110 , and a lower cover  130  stacked on and in contact with a lower surface of the body  110 , having air channels  111  formed between the body  110  and the upper cover  120 , and having fuel channels  112  formed between the body  110  and the lower cover  130 ; a heating element  200  stacked on and coupled to the end cell  100 ; and an electricity collecting plate  300  stacked on and in contact with the heating element  200 . 
         [0016]    Fusing protrusions may be formed to protrude on any one or more of the upper surface of the body  110  and a lower surface of the upper cover  120 , fusing grooves may be concavely formed at both sides of the fusing protrusions so as to be in contact with the fusing protrusions, and the fusing protrusions may be melted, such that the body  110  and the upper cover  120  are bonded to each other, and fusing protrusions may be formed to protrude on any one or more of the lower surface of the body  110  and an upper surface of the lower cover  130 , fusing grooves may be concavely formed at both sides of the fusing protrusions so as to be in contact with the fusing protrusions, and the fusing protrusions may be melted, such that the body  110  and the lower cover  130  are bonded to each other. 
         [0017]    The fusing protrusions and the fusing grooves may be formed at both sides of each of the air channels  111  and the fuel channels  112  so as to be spaced apart from the air channels  111  and the fuel channels  112 . 
         [0018]    In the end cell  100 , fusing protrusions may be melted by vibration fusion or laser fusion, such that the body  110  and the upper cover  120  are bonded to each other and the body  110  and the lower cover  130  are bonded to each other, and the body  110 , the upper cover  120 , and the lower cover  130  are thus formed integrally with one another. 
         [0019]    A seating groove may be concavely formed in a lower surface of the lower cover  130 , and the electricity collecting plate  300  may be stacked on a lower surface of the heating element  200  so as to be in contact with the lower surface of the heating element  200 , such that the heating element  200  and the electricity collecting plate  300  are inserted into and seated in the seating groove. 
         [0020]    A cross-sectional area of a portion in which a fusing protrusion is melted may be smaller than that of a pair of fusing grooves formed at both sides of each fusing protrusion. 
         [0021]    Protruding parts  115  may be formed to protrude on the upper surface of the body  110 , fusing protrusions  113  may be formed to protrude on upper surfaces of the protruding parts  115 , and insertion grooves  121  may be concavely formed at positions corresponding to those of the protruding parts  115  in the upper cover  120 , such that the protruding parts  115  and the fusing protrusions  113  are inserted into the insertion grooves  121  and the fusing protrusions  113  are melted to be fused to the insertion grooves  121 . 
         [0022]    A height of the insertion groove  121  may be higher than that of the protruding part  115 , and a cross-sectional area of a space between the protruding part  115  and the insertion groove  121  may be greater than that of a portion in which the fusing protrusion  113  is melted. 
         [0023]    A lead terminal  140  in which terminals  141  and injection-molded members  142  are formed integrally with each other by insert-injection-molding the terminals  141  may be again insert-injection-molded, such that the body  110  and the lead terminal  140  are formed integrally with each other. 
         [0024]    The end cell heater for a fuel cell may further include: an end plate  600  stacked on the upper cover  120 ; and a gasket  500  interposed between and closely adhering to the upper cover  120  and the end plate  600 . 
         [0025]    The gasket  500  may include sealing members  530  formed to protrude on both surfaces of a plate  510  and a plurality of communication holes  520  formed in the plate  510  so as to penetrate through upper and lower surfaces of the plate  510 , and the sealing members  530  formed on the upper and lower surfaces of the plate  510  may be connected to each other through the communication holes  520 . 
         [0026]    In the gasket  500 , the plate  510  and the sealing members  530  may be formed integrally with each other by insert-injection-molding. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]      FIG. 1  is a perspective view illustrating a fuel cell according to the related art. 
           [0028]      FIG. 2  is a cross-sectional view illustrating an end cell heater for a fuel cell according to a first exemplary embodiment of the present invention. 
           [0029]      FIGS. 3 to 5  are partial cross-sectional views illustrating a fusing process of manufacturing an end cell heater according to the present invention. 
           [0030]      FIG. 6  is a cross-sectional view illustrating an end cell heater for a fuel cell according to a second exemplary embodiment of the present invention. 
           [0031]      FIGS. 7 to 10  are a cross-sectional view and partial cross-sectional views illustrating various examples of an end cell heater for a fuel cell according to the present invention. 
           [0032]      FIG. 11  is a cross-sectional view illustrating a relationship between a cross-sectional area of a portion in which a fusing protrusion is melted at the time of fusion and a cross-sectional area of a space in which a flash formed by melting the fusing protrusion may be filled. 
           [0033]      FIG. 12  is a perspective view illustrating a lead terminal according to the present invention. 
           [0034]      FIGS. 13 and 14  are, respectively, an exploded perspective view and an assembled perspective view illustrating the end cell heater for a fuel cell according to a second exemplary embodiment of the present invention. 
           [0035]      FIG. 15  is a cross-sectional view illustrating an example of a gasket and an end plate according to the present invention. 
           [0036]      FIG. 16  is a perspective view illustrating the gasket of  FIG. 15 . 
           [0037]      FIG. 17  is an exploded perspective view illustrating another example of a gasket according to the present invention. 
           [0038]      FIGS. 18 and 19  are, respectively, an assembled perspective view and an exploded perspective view illustrating a fuel cell including the end cell heater for a fuel cell according to the present invention. 
           [0000]    
         
           
                 
               
                 
                 
               
                 
                 
                 
               
                 
                 
               
                 
                 
                 
               
                 
                 
               
                 
                 
                 
               
                 
                 
               
                 
                 
                 
               
                 
                 
               
                 
                 
                 
               
             
                 
                     
                 
                 
                   [Detailed Description of Main Elements] 
                 
                 
                     
                 
               
               
                 
                     
                 
               
            
             
                 
                     
                   1000: end cell heater for fuel cell 
                 
                 
                     
                    100: end cell 
                 
                 
                     
                    110: body 
                 
               
            
             
                 
                     
                    111: air channel 
                    112: fuel channel 
                 
                 
                     
                    113: fusing protrusion 
                    114: fusing groove 
                 
               
            
             
                 
                     
                    115: protruding part 
                 
               
            
             
                 
                     
                    120: upper cover 
                    121: insertion groove 
                 
               
            
             
                 
                     
                    130: lower cover 
                 
                 
                     
                    140: lead terminal 
                 
                 
                     
                    141: terminal 
                 
                 
                     
                    142: injection-molded member 
                 
               
            
             
                 
                     
                    151: air passage 
                    152: fuel passage 
                 
               
            
             
                 
                     
                    200: heating element 
                 
                 
                     
                    300: electricity collecting plate 
                 
                 
                     
                    310: electricity collecting terminal 
                 
                 
                     
                    400: heat insulating sheet 
                 
                 
                     
                    500: gasket 
                 
               
            
             
                 
                     
                    510: plate 
                    520: communication hole 
                 
                 
                     
                    530: sealing member 
                    531: sealing member 
                 
               
            
             
                 
                     
                    540: passage hole 
                 
                 
                     
                    550: electricity collecting terminal hole 
                 
                 
                     
                    600: end plate 
                 
                 
                     
                   2000: fuel cell 
                 
               
            
             
                 
                     
                   1100: fuel cell stack 
                   1100a: reaction cell 
                 
                 
                     
                   1110: air passage 
                    1120: fuel passage 
                 
                 
                     
                   1400: cover 
                    1410: air passage 
                 
                 
                     
                   1420: fuel passage 
                    1500: fastening member 
                 
                 
                     
                     
                 
               
            
           
         
       
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0039]    Hereinafter, an end cell heater for a fuel cell according to the present invention having the configuration as described above will be described in detail with reference to the accompanying drawings. 
       First Exemplary Embodiment 
       [0040]      FIG. 2  is a cross-sectional view illustrating an end cell heater for a fuel cell according to a first exemplary embodiment of the present invention. 
         [0041]    As illustrated, the end cell heater  1000  for a fuel cell according to a first exemplary embodiment of the present invention may be configured to include an end cell  100  including a body  110  and an upper cover  120  stacked on and in contact with an upper surface of the body  110 , and having air channels  111  formed between the body  110  and the upper cover  120 ; a heating element  200  stacked on and coupled to the end cell  100 ; and an electricity collecting plate  300  stacked on and in contact with the heating element  200 . 
         [0042]    First, the end cell  100  may mainly consist of the body  110  and the upper cover  120 , and both of the body  110  and the upper cover  120  may be formed of, for example, a plastic plate. In addition, the upper cover  120  is stacked on the upper surface of the body  110 , such that the body  110  and the upper cover  120  may be coupled or bonded to each other so that surfaces thereof facing each other are in contact with each other. In addition, the air channels  111  are formed between the body  110  and the upper cover  120 , such that air may flow along the air channels  111 . In this case, the air channels  111  may be concavely formed in the upper surface of the body  110  or a lower surface of the upper cover  120 . As an example, as illustrated, the air channels  111  may be concavely formed in the upper surface of the body  110 , and opened upper sides of the air channels  111  may be closed by the upper cover  120  coupled or bonded to the upper surface of the body  110 . In addition, the end cell  100  may be formed in various shapes such as a quadrangular shape having a length greater than a width, and the like, and may have air passages formed at both sides thereof in a length direction so as to penetrate through upper and lower surfaces thereof, and the air passages may be connected to the air channels. In addition, the end cell  100  may have a through-hole formed at a central side thereof so as to penetrate through the upper and lower surfaces thereof, and an electricity collecting terminal  310  formed on an electricity collecting plate  300  to be described below may be inserted into the through-hole so as to penetrate through the through-hole. 
         [0043]    The heating element  200 , which is a means capable of receiving electricity and generating heat, may be, for example, a film heater formed in a film shape, may be stacked on and coupled to the end cell  100 , be inserted into and seated in a seating groove concavely formed in a lower surface of the body  110  of the end cell  100  as an example, and be coupled and fixed to the end cell  100 . In addition, the heating element  200  may also have a through-hole formed therein so as to penetrate through upper and lower surfaces thereof so that the electricity collecting terminal  310  of the electricity collecting plate  300  may penetrate therethrough and be inserted thereinto. In addition, a heat insulating sheet  400  may be interposed between the end cell  100  and the heating element  200 , may prevent heat generated from the heating element  200  from being transferred to the end cell  100  formed of a plastic material, and may be formed of an electrical insulating material to perform an electrical insulating function. 
         [0044]    The electricity collecting plate  300 , which is a part capable of collecting and transferring electricity generated in a fuel cell stack  1100 , may be a metal plate formed of an electrically conductive material to be thus electrically conducted to the fuel cell stack. In addition, the electricity collecting plate  300  may be inserted into and seated in the seating groove formed in the body  110  of the end cell  100 , and may be stacked to closely adhere to and be in contact with the lower surface of the heating element  200  to be thus coupled to the end cell  100 . In addition, the electricity collecting terminal  310  may be formed to protrude on an upper surface of the electricity collecting plate  300 , and may be inserted and coupled into the through-holes of the end cell  100  and the heating element  200  so as to pass through the through-holes. 
         [0045]    Therefore, the end cell heater for a fuel cell according to the present invention as described above is stacked on and is coupled to an outer side of the outermost reaction cell of the fuel cell stack so as to closely adhere to the outer side of the outermost reaction cell to thus prevent water in the reaction cell from being frozen, thereby making it possible to improve initial start ability and initial driving performance of the fuel cell. 
         [0046]    In addition, fusing protrusions are formed to protrude on any one or more of the upper surface of the body  110  and the lower surface of the upper cover  120 , fusing grooves are concavely formed at both sides of the fusing protrusions so as to be in contact with the fusing protrusions, and the fusing protrusions are melted, such that the body  110  and the upper cover  120  may be bonded to each other. 
         [0047]    That is, as an example, as illustrated in  FIGS. 3 to 5 , the fusing protrusions  113  may be formed to protrude on the upper surface of the body  110 , and the fusing grooves  114  may be concavely formed at both sides of the fusing protrusions  113  so as to be in contact with the fusing protrusions  113 . A description will be provided on the basis of the fusing protrusions  113  and the fusing grooves  114  formed at an upper side of the body  110 . The fusing protrusions  113  may be formed to protrude to be upwardly convex from the upper surface of the body  110 , and the fusing grooves  114  may be formed adjacently to the fusing protrusions  113  at both sides of the fusing protrusions  113  so as to be downwardly concave from the upper surface of the body  110 . In addition, the lower surface of the upper cover  120  may be a flat surface. Therefore, end portions of the fusing protrusions  113  are melted by fusion, such that the body  110  and the upper cover  120  may be bonded and coupled to each other, and a flash formed by melting and pressing the fusing protrusions  113  may be filled in the fusing grooves  114 . 
         [0048]    In addition, the fusing protrusions and the fusing grooves may be formed at both sides of the air channels  111  so as to be spaced apart from the air channels  111 . 
         [0049]    That is, the number of air channels  111  may be one or plural, the fusing protrusions  113  and the fusing grooves  114  may be formed along a path in which the air channels  111  are formed, and the fusing protrusions  113  and the fusing grooves  114  may be formed at both sides of the air channels  111  so as to be spaced apart from the air channels  111 . Therefore, as illustrated, a pair of fusing protrusions  113  may be formed per air channel  111 , one fusing protrusion  113  may be formed at each of both sides of one air channel  111 , a pair of fusing grooves  114  may be formed per one fusing protrusion  113 , and one fusing groove  114  may be formed at each of both sides of one fusing protrusion  113 . In other words, protrusions and grooves of which one set is formed by the fusing grooves  114  formed at both sides of one fusing protrusion  113  may be formed at both sides of the channels, and one set of protrusions and grooves may be formed at both sides of each of the channels. Therefore, the fusing protrusions are melted along the channels, such that contact surfaces are bonded to each other, thereby making it possible to secure air-tightness of each of the channels and secure pressure resistance properties of fluids flowing along the channels. 
         [0050]    In addition, in the end cell  100 , the fusing protrusions are melted by vibration fusion or laser fusion, such that the body  110  and the upper cover  120  may be bonded to and formed integrally with each other. 
         [0051]    That is, in a state in which the body  110  and the upper cover  120  are pressed in a vertical direction so as to closely adhere to each other after the upper cover  120  is disposed on the body  110  in a state in which the end portions of the fusing protrusions  113  are not melted, vibrations such as ultrasonic vibrations, or the like, are applied, such that heat is generated on a surface on which the fusing protrusions  113  and the upper cover  120  are in contact with each other to melt the fusing protrusions  113 , thereby making it possible to bond the body  110  and the upper cover  120  to each other. In this case, the melted flash formed by melting the fusing protrusions  113  may be pushed into the fusing grooves  114 . Therefore, the upper surface of the body  110  and the lower surface of the upper cover  120  may closely adhere and be bonded to each other, and the melted flash may not be introduced between the upper surface of the body  110  and the lower surface of the upper cover  120 . 
         [0052]    Alternatively, the body  110  is formed as an absorption layer capable of absorbing a laser beam, and the upper cover  120  is formed as a transmission layer through which the laser beam may transmit, such that the fusing protrusions  113  are melted and fused by the laser fusion, and the body  110  and the upper cover  120  may thus be formed integrally with each other. 
         [0053]    That is, in the state in which the body  110  and the upper cover  120  are pressed in the vertical direction so as to closely adhere to each other after the upper cover  120  is disposed on the body  110  in the state in which the end portions of the fusing protrusions  113  are not melted, the laser beam is irradiated to portions of the fusing protrusions  113 , thereby making it possible to bond portions at which the fusing protrusions  113  and the upper cover  120  are in contact with each other to each other while melting the fusing protrusions  113 . Here, the body  110  on which the fusing protrusions  113  are formed is formed to have a black color so that the laser beam may be absorbed therein, such that the body  110  may be formed as a laser absorption layer, and the upper cover  120  is transparently formed so that the laser beam may pass therethrough, such that the upper cover  120  may be formed of a laser transmission layer. Therefore, the laser beam is irradiated from above the upper cover  120 , and may pass through the upper cover  120  to allow the fusing protrusions  113  to be melted and fused. Also in this case, the melted flash formed by melting the fusing protrusions  113  may be pushed into the fusing grooves  114 , and the upper surface of the body  110  and the lower surface of the upper cover  120  may thus closely adhere and be bonded to each other. 
         [0054]    In addition, the seating groove is concavely formed in the lower surface of the body  110 , and the electricity collecting plate  300  is stacked on the lower surface of the heating element  200  so as to be in contact with the lower surface of the heating element  200 , such that the heating element  200  and the electricity collecting plate  300  may be inserted into and seated in the seating groove. 
         [0055]    That is, as described above, the heating element  200  and the electricity collecting plate  300  may be inserted into and seated in the seating groove concavely formed in the lower surface of the body  110 , and the electricity collecting plate  300  is disposed beneath the heating element  200  so as to be in contact with the heating element  200 . In this case, the heat insulating sheet  400  may be interposed between a lower surface of the seating groove and the heating element  200 , such that the heat insulating sheet  400  may be disposed on the heating element  200 . In addition, a lower surface of the electricity collecting plate  300  may be formed to further protrude as compared with the lower surface of the body  110  of the end cell  100  or coincide with the lower surface of the body  110  of the end cell  100 . Therefore, when the electricity collecting plate of the end cell heater for a fuel cell according to the present invention is coupled to the reaction cell of the fuel cell stack so as to closely adhere to the reaction cell, electrical insulation and air-tightness of the heating element  200  and the electricity collecting plate  300  may be easily maintained. 
       Second Exemplary Embodiment 
       [0056]      FIG. 6  is a cross-sectional view illustrating an end cell heater for a fuel cell according to a second exemplary embodiment of the present invention. 
         [0057]    As illustrated, the end cell heater  1000  for a fuel cell according to a second exemplary embodiment of the present invention may be configured to include an end cell  100  including a body  110 , an upper cover  120  stacked on and in contact with an upper surface of the body  110 , and a lower cover  130  stacked on and in contact with a lower surface of the body  110 , having air channels  111  formed between the body  110  and the upper cover  120 , and having fuel channels  112  formed between the body  110  and the lower cover  130 ; a heating element  200  stacked on and coupled to the end cell  100 ; and an electricity collecting plate  300  stacked on and in contact with the heating element  200 . 
         [0058]    First, the end cell  100  may mainly consist of the body  110 , the upper cover  120 , and lower cover  130 , and all of the body  110 , the upper cover  120 , and the lower cover  130  may be formed of, for example, a plastic plate. In addition, the upper cover  120  is stacked on the upper surface of the body  110 , such that the body  110  and the upper cover  120  may be coupled or bonded to each other so that surfaces thereof facing each other are in contact with each other, and the lower cover  130  is stacked on the lower surface of the body  110 , such that the body  110  and the lower cover  130  may be coupled or bonded to each other so that surfaces thereof facing each other are in contact with each other. In addition, the air channels  111  are formed between the body  110  and the upper cover  120 , such that air may flow along the air channels  111 , and the fuel channels  112  are formed between the body  110  and the lower cover  130 , such that a fuel such as hydrogen, or the like, may flow along the fuel channels  112 . In this case, the air channels  111  may be concavely formed in the upper surface of the body  110  or a lower surface of the upper cover  120 . As an example, as illustrated, the air channels  111  may be concavely formed in the upper surface of the body  110 , and opened upper sides of the air channels  111  may be closed by the upper cover  120  coupled or bonded to the upper surface of the body  110 . In addition, the fuel channels  112  may be concavely formed in the lower surface of the body  110  or an upper surface of the lower cover  130 . As an example, as illustrated, the fuel channels  112  may be concavely formed in the lower surface of the body  110 , and opened lower sides of the fuel channels  112  may be closed by the lower cover  130  coupled or bonded to the lower surface of the body  110 . In addition, the end cell  100  may be formed in various shapes such as a quadrangular shape having a length greater than a width, and the like, and may have air passages and fuel passages formed at both sides thereof in a length direction so as to penetrate through upper and lower surfaces thereof, the air passages may be connected to the air channels, and the fuel passages may be connected to the fuel channels. In addition, the end cell  100  may have a through-hole formed at a central side thereof so as to penetrate through the upper and lower surfaces thereof, and an electricity collecting terminal  310  formed on the electricity collecting plate  300  may be inserted into the through-hole so as to penetrate through the through-hole. 
         [0059]    The heating element  200 , which is a means capable of receiving electricity and generating heat, may be, for example, a film heater formed in a film shape, may be stacked on and coupled to the end cell  100 , and be inserted into and seated in a seating groove concavely formed in a lower surface of the lower cover  130  of the end cell  100  as an example to be thus coupled and fixed to the end cell  100 . In addition, the heating element  200  may also have a through-hole formed therein so as to penetrate through upper and lower surfaces thereof so that the electricity collecting terminal  310  of the electricity collecting plate  300  may penetrate therethrough and be inserted thereinto. In addition, a heat insulating sheet  400  may be interposed between the end cell  100  and the heating element  200 , may prevent heat generated from the heating element  200  from being transferred to the end cell  100  formed of a plastic material, and may be formed of an electrical insulating material to perform an electrical insulating function. 
         [0060]    The electricity collecting plate  300 , which is a part capable of collecting and transferring electricity generated in a fuel cell stack, may be a metal plate formed of an electrically conductive material to be thus electrically conducted to the fuel cell stack. In addition, the electricity collecting plate  300  may be inserted into and seated in the seating groove formed in the lower cover  130  of the end cell  100 , and may be stacked to closely adhere to and be in contact with the lower surface of the heating element  200  to be thus coupled to the end cell  100 . In addition, the electricity collecting terminal  310  may be formed to protrude on an upper surface of the electricity collecting plate  300 , and may be inserted and coupled into the through-holes of the end cell  100  and the heating element  200  so as to pass through the through-holes. 
         [0061]    Therefore, the end cell heater for a fuel cell according to the present invention as described above is stacked on and is coupled to an outer side of the outermost reaction cell of the fuel cell stack so as to closely adhere to the outer side of the outermost reaction cell to thus prevent water in the reaction cell from being frozen, thereby making it possible to improve initial start ability and initial driving performance of the fuel cell. 
         [0062]    In addition, fusing protrusions are formed to protrude on any one or more of the upper surface of the body  110  and the lower surface of the upper cover  120 , fusing grooves are concavely formed at both sides of the fusing protrusions so as to be in contact with the fusing protrusions, and the fusing protrusions are melted, such that the body  110  and the upper cover  120  may be bonded to each other, and fusing protrusions are formed to protrude on any one or more of the lower surface of the body  110  and the upper surface of the lower cover  130 , fusing grooves are concavely formed at both sides of the fusing protrusions so as to be in contact with the fusing protrusions, and the fusing protrusions are melted, such that the body  110  and the lower cover  130  may be bonded to each other. 
         [0063]    That is, as an example, the fusing protrusions  113  may be formed to protrude on the upper surface and the lower surface of the body  110 , the fusing grooves  114  may be concavely formed at both sides of the fusing protrusions  113  so as to be in contact with the fusing protrusions  113 , and the lower surface of the upper cover  120  and the upper surface of the lower cover  130  may be flat surfaces. Here, a description will be provided on the basis of the fusing protrusions  113  and the fusing grooves  114  formed at an upper side of the body  110 . The fusing protrusions  113  may be formed to protrude to be upwardly convex from the upper surface of the body  110 , and the fusing grooves  114  may be formed adjacently to the fusing protrusions  113  at both sides of the fusing protrusions  113  so as to be downwardly concave from the upper surface of the body  110 . Therefore, end portions of the fusing protrusions  113  are melted by fusion, such that the body  110  and the upper cover  120  may be bonded and coupled to each other, and a flash formed by melting and pressing the fusing protrusions  113  may be filled in the fusing grooves  114 . Likewise, the body  110  and the lower cover  130  may be bonded and coupled to each other by fusion. 
         [0064]    In addition, the fusing protrusions and the fusing grooves may be formed at both sides of each of the air channels  111  and the fuel channels  112  so as to be spaced apart from the air channels  111  and the fuel channels  112 . 
         [0065]    That is, the number of air channels  111  may be one or plural, the fusing protrusions  113  and the fusing grooves  114  may be formed along a path in which the air channels  111  are formed, and the fusing protrusions  113  and the fusing grooves  114  may be formed at both sides of the air channels  111  so as to be spaced apart from the air channels  111 . Therefore, as illustrated, a pair of fusing protrusions  113  may be formed per air channel  111 , one fusing protrusion  113  may be formed at each of both sides of one air channel  111 , a pair of fusing grooves  114  may be formed per one fusing protrusion  113 , and one fusing groove  114  may be formed at each of both sides of one fusing protrusion  113 . In other words, protrusions and grooves of which one set is formed by the fusing grooves  114  formed at both sides of one fusing protrusion  113  may be formed at both sides of the channels, and one set of protrusions and grooves may be formed at both side of each of the channels. Therefore, the fusing protrusions are melted along the channels, such that contact surfaces are bonded to each other, thereby making it possible to secure air-tightness of each of the channels and secure pressure resistance properties of fluids flowing along the channels. Likewise, the number of fuel channels  112  may also be one or plural, the fusing protrusions  113  and the fusing grooves  114  may be formed along a path in which the fuel channels  112  are formed, and the fusing protrusions  113  and the fusing grooves  114  may be formed at both sides of the fuel channels  112  so as to be spaced apart from the fuel channels  112 . 
         [0066]    In addition, in the end cell  100 , the fusing protrusions are melted by vibration fusion or laser fusion, such that the body  110  and the upper cover  120  may be bonded to each other and the body  110  and the lower cover  130  may be bonded to each other. As a result, the body  110 , the upper cover  120 , and the lower cover  130  may be formed integrally with one another. 
         [0067]    That is, in a state in which the upper cover  120 , the body  110 , and the lower cover  130  are sequentially stacked and are pressed in a vertical direction so as to closely adhere to one another after the upper cover  120  is disposed on the body  110  and the lower cover  130  is disposed beneath the body  110  in a state in which the end portions of the fusing protrusions  113  are not melted, vibrations such as ultrasonic vibrations, or the like, are applied, such that heat is generated on a surface on which the fusing protrusions  113  formed at the upper side of the body  110  and the upper cover  120  are in contact with each other to melt the fusing protrusions  113 , thereby making it possible to bond the body  110  and the upper cover  120  to each other. In addition, heat is generated on a surface on which the fusing protrusions  113  formed at a lower side of the body  110  and the lower cover  130  are in contact with each other to melt the fusing protrusions  113 , thereby making it possible to bond the body  110  and the lower cover  130  to each other. In this case, the melted flash formed by melting the fusing protrusions  113  may be pushed into the fusing grooves  114 . Therefore, the upper surface of the body  110  and the lower surface of the upper cover  120  may closely adhere and be bonded to each other, and the lower surface of the body  110  and the upper surface of the lower cover  130  may closely adhere and be bonded to each other. In this case, the melted flash may not be introduced between the upper surface of the body  110  and the lower surface of the upper cover  120  by the fusing grooves  114 . 
         [0068]    Alternatively, the body  110  is formed as an absorption layer capable of absorbing a laser beam, and the upper cover  120  and the lower cover  130  are formed as transmission layers through which the laser beam may transmit, such that the fusing protrusions  113  are melted and fused by the laser fusion, and the upper cover  120 , the body  110 , and the lower cover  130  may thus be formed integrally with one another. 
         [0069]    That is, in a state in which the upper cover  120 , the body  110 , and the lower cover  130  are sequentially stacked and are pressed in a vertical direction so as to closely adhere to one another after the upper cover  120  is disposed on the body  110  and the lower cover  130  is disposed beneath the body  110  in the state in which the end portions of the fusing protrusions  113  are not melted, the laser beam is irradiated from above the upper cover  120  and below the lower cover  130  toward the fusing protrusions  113 , thereby making it possible to bond portions at which the fusing protrusions  113  and the upper cover  120  are in contact with each other to each other and bond portions at which the fusing protrusions  113  and the lower cover  130  are in contact with each other to each other while melting the fusing protrusions  113 . Here, the body  110  on which the fusing protrusions  113  are formed is formed to have a black color so that the laser beam may be absorbed therein, such that the body  110  may be formed as a laser absorption layer, and the upper cover  120  and the lower cover  130  are transparently formed so that the laser beam may pass therethrough, such that the upper cover  120  and the lower cover  130  may be formed of laser transmission layers. Therefore, the laser beam is irradiated from above the upper cover  120 , and may pass through the upper cover  120  to allow the fusing protrusions  113  to be melted and fused and may pass through the lower cover  130  to allow the fusing protrusions  113  to be melted and fused. Also in this case, the melted flash formed by melting the fusing protrusions  113  may be pushed into the fusing grooves  114 . Therefore, the upper surface of the body  110  and the lower surface of the upper cover  120  may closely adhere and be bonded to each other, and the lower surface of the body  110  and the upper surface of the lower cover  130  may closely adhere and be bonded to each other. 
         [0070]    In addition, the seating groove is concavely formed in the lower surface of the lower cover  130 , and the electricity collecting plate  300  is stacked on the lower surface of the heating element  200  so as to be in contact with the lower surface of the heating element  200 , such that the heating element  200  and the electricity collecting plate  300  may be inserted into and seated in the seating groove. 
         [0071]    That is, as described above, the heating element  200  and the electricity collecting plate  300  may be inserted into and seated in the seating groove concavely formed in the lower surface of the lower cover  130 . In this case, the electricity collecting plate  300  is disposed beneath the heating element  200  so as to be in contact with the heating element  200 , and the heat insulating sheet  400  may be interposed between a lower surface of the seating groove and the heating element  200 , such that the heat insulating sheet  400  may be disposed on the heating element  200 . In addition, a lower surface of the electricity collecting plate  300  may be formed to further protrude as compared with the lower surface of the lower cover  130  or coincide with the lower surface of the lower cover  130 . Therefore, when the electricity collecting plate of the end cell heater for a fuel cell according to the present invention is coupled to the reaction cell of the fuel cell stack so as to closely adhere to the reaction cell, electrical insulation and air-tightness of the heating element  200  and the electricity collecting plate  300  may be easily maintained. 
         [0072]    Contents to be described below may be applied to both of the first exemplary embodiment and the second exemplary embodiment of the present invention described above. 
         [0073]    First, a cross-sectional area of a portion in which the fusing protrusion  113  is melted may be smaller than that of a pair of fusing grooves  114  formed at both sides of each fusing protrusion  113 . 
         [0074]    That is, as described above, the melted flash formed by melting the fusing protrusion  113  at the time of the fusion is pushed into the fusing grooves  114  formed at both sides of the fusing protrusion  113 , and spaces of the pair of fusing grooves  114  are wider than an amount of flash, such that the flash is not pushed into a space between the upper surface of the body  110  and the lower surface of the upper cover  120  and is not pushed into a space between the lower surface of the body  110  and the upper surface of the lower cover  130 . Therefore, the upper surface of the body  110  and the lower surface of the upper cover  120  may closely adhere to each other, and the lower surface of the body  110  and the upper surface of the lower cover  130  may closely adhere to each other. 
         [0075]    In addition, protruding parts  115  are formed to protrude on the upper surface of the body  110 , fusing protrusions  113  are formed to protrude on upper surfaces of the protruding parts  115 , and insertion grooves  121  are concavely formed at positions corresponding to those of the protruding parts  115  in the upper cover  120 , such that the protruding parts  115  and the fusing protrusions  113  may be inserted into the insertion grooves  121  and the fusing protrusions  113  may be melted to be fused to the insertion grooves  121 . 
         [0076]    That is, as illustrated in  FIGS. 7 to 10 , the protruding part  115  formed to protrude upwardly from the upper surface of the body  110  may be inserted and coupled into the insertion groove  121  concavely formed upwardly in the lower surface of the upper cover  120 , such that the body  110  and the upper cover  120  may be bonded to each other in a state in which positions of the body  110  and the upper cover  120  in a horizontal direction are accurately fixed. In this case, the fusing protrusion  113  may be formed to protrude upwardly from the upper surface of the protruding part  115 , have a width narrower than that of the protruding part  115 , and be melted to be bonded to the insertion groove  121 . In addition, the protruding part  115  and the insertion groove  121  may be formed at the outermost portion of the end cell  100  in the horizontal direction, and the protruding part  115  may be formed so that the fusing protrusion  113  and the fusing groove  114  of the body  110  are disposed at an inner side in the horizontal direction. In addition, protruding parts  115  and fusing protrusions  113 , and insertion grooves  121  may also be formed in the body  110  and the lower cover  130 , respectively, as in the coupled and bonded structure between the body  110  and the upper cover  120  described above. 
         [0077]    In addition, a height of the insertion groove  121  is higher than that of the protruding part  115 , and a cross-sectional area of a space between the protruding part  115  and the insertion groove  121  may be greater than that of a portion in which the fusing protrusion  113  is melted. 
         [0078]    That is, describing the body  110  and the upper cover  120  by way of example, in the case in which the fusing protrusion  113  is formed upwardly from the upper surface of the protruding part  115  of the body  110  as illustrated in  FIGS. 7 to 10 , the height of the insertion groove  121  is higher than that of the protruding part  115 , such that the fusing protrusion is in a state in which it is maximally pressed when the upper surface of the body  110  and the lower surface of the upper cover  120  closely adhere to each other while the fusing protrusion is melted. In this case, the flash formed by melting the fusing protrusion is pushed into a space portion formed between the protruding part  115  and the insertion groove  121 . For this reason, the space portion is formed to have a volume greater than an amount of fusing protrusion  113  that may be maximally melted. Here, the volume may be calculated by a cross-sectional area, and in the case in which the protruding part  115  and the insertion groove  121  are formed at the same width, a minimum cross-sectional area of the space portion, which is a value obtained by multiplying a difference between the width of the protruding part  115  and the width of the fusing protrusion  113  by a difference between the height of the insertion groove  121  and the height of the protruding part  115  may be designed to be greater than that of a portion in which the fusing protrusion may be maximally melted and pressed, which is a value obtained by multiplying a value obtained by subtracting the height of the insertion groove from the sum of the height of the protruding part and the height of the insertion groove by the width of the fusing protrusion. That is, as illustrated in  FIG. 11 , a cross-sectional area of part A may be smaller than the sum of cross-sectional areas of part B, which is both sides of the fusing protrusion  113 . In addition, although not illustrated, insertion grooves may also be formed in the lower cover  130 , and the protruding parts  115  may be inserted and coupled to the insertion groove. 
         [0079]    In addition, a lead terminal  140  in which terminals  141  and injection-molded members  142  are formed integrally with each other by insert-injection-molding the terminals  141  is again insert-injection-molded, such that the body  110  and the lead terminal  140  may be formed integrally with each other. 
         [0080]    This is to allow the terminals  141  to be formed integrally with the body  110  when the body  110  is manufactured by injection-molding. Referring to  FIGS. 12 and 14 , after two terminals are disposed in parallel with each other so as to be spaced apart from each other and are fixed to an injection mold, primary injection-molding is performed, such that the terminals  141  are insert-injection-molded to be formed integrally with the injection-molded members  142 , thereby making it possible to form an integral lead terminal  140 . After the lead terminal  140  as described above is again fixed to the injection mold, secondary injection-molding is again performed, such that the lead terminal  140  may be insert-injection-molded to be formed integrally with the body  110 . 
         [0081]    In addition, the end cell heater  1000  for a fuel cell may be configured to further include an end plate  600  stacked on the upper cover  120  and a gasket  500  interposed between and closely adhering to the upper cover  120  and the end plate  600 . 
         [0082]    That is, referring to  FIGS. 15 and 16 , since the end cell  100  is formed of a plastic material, the end plate  600  formed of a metal may be coupled to one surface of the end cell  100  in order to increase mechanical rigidity. In this case, the gasket  500  may be interposed between and closely adhere to the end cell  100  and the end plate  600  in order to maintain air-tightness on a contact surface between the end cell  100  and the end plate  600 . 
         [0083]    Here, the gasket  500  includes sealing members  530  formed to protrude on both surfaces of a plate  510  and a plurality of communication holes  520  formed in the plate  510  so as to penetrate through upper and lower surfaces of the plate  510 , and the sealing members  530  formed on the upper and lower surfaces of the plate  510  may be connected to each other through the communication holes  520 . 
         [0084]    That is, the gasket  500  may include the plate  510  and the sealing members  530  having a plate shape, and the sealing members  530  may be formed to protrude on both surfaces of the plate  510 . In addition, the communication holes  520  penetrating through both surfaces of the plate  510  may be formed in the plate  510 , and the sealing members  530  formed on both surfaces of the plate  510  may be connected to each other through the communication holes  520 . Therefore, the sealing members  530  that are generally formed of a rubber or silicone material to have a difficulty in maintaining shapes are coupled and fixed to the plate  510 , thereby making it possible to easily maintain shapes of the sealing member  530  and prevent moisture, foreign materials, and the like, from being introduced between the end plate  600  and the end cell  100 . 
         [0085]    In this case, seating grooves may be concavely formed along portions of both surfaces of the plate  510  on which the sealing members are formed so that portions of the sealing members may be inserted, and separation of the sealing members may thus be prevented. In addition, the end plate  600  may have a through-hole formed therein so that the electricity collecting terminal  310  may pass therethrough, and may have passages formed therein so as to be connected to the passages connected to the channels of the end cell  100 . In addition, the gasket  500  may also have electricity collecting terminal holes  550  therein so that the electricity collecting terminal passes therethrough, and have passage holes  540  formed therein so as to be connected to the passages. In addition, a space between an outer peripheral surface of the electricity collecting terminal  310  penetrating through the end plate  600  and the through-hole of the end plate  600  is sealed by a sealant, or the like, thereby making it possible to prevent moisture, foreign materials, and the like, from being introduced toward the electricity collecting plate  300 . 
         [0086]    In addition, in the gasket  500 , the plate  510  and the sealing members  530  may be formed integrally with each other by insert-injection-molding. 
         [0087]    That is, after the plate  510  is formed of a metal, insert-injection-molding is performed, such that the gasket  500  may be easily formed in a form in which the sealing members  530  formed on both surfaces of the plate  510  are connected to each other through the communication holes  520  formed in the plate  510 . 
         [0088]    In addition, as illustrated in  FIG. 17 , the gasket  500  may include only sealing members  530  formed of a rubber or silicone material without including the plate  510 , and sealing members  531  may be disposed at both sides in the length direction to allow air-tightness of the air passages and the fuel passages formed in the end cell  110  to be maintained. 
         [0089]    In addition, a thermal pad may be interposed between and closely adhere to the heating element  200  and the electricity collecting plate  300 . That is, although not illustrated, the thermal pad is interposed between and closely adheres to the heating element  200  and the electricity collecting plate  300  so as to improve a thermal conduction function, thereby making it possible to allow the heat generated from the heating element  200  to be well transferred to a reaction cell  1100   a  of the fuel cell stack  1100  through the electricity collecting plate  300 . In this case, the thermal pad may also have a through-hole formed therein so that the electricity collecting terminal  310  may penetrate therethrough. 
         [0090]    In addition, a fuel cell  2000  including an end cell heater for a fuel cell according to the present invention may be configured to include a fuel cell stack  1100  formed by stacking unit cells and having air passages  1110  and fuel passages  1120  each formed at both sides thereof so as to penetrate through both surfaces thereof in a stack direction; and the end cell heaters  1000  coupled to the fuel cell stack  1100  and stacked on outer sides of unit cells stacked at the outermost portions among the unit cells, such that passages are connected to each other. 
         [0091]    That is, the fuel cell  2000  may be formed by stacking the end cell heaters  1000  on the fuel cell stack  1100  formed by stacking the reaction cells  1100   a , as illustrated in  FIGS. 1.8 and 19 , and the end cell heaters  1000  may be stacked on and closely adhere to the reaction cells  1100   a  stacked at the outermost portions of the fuel cell stack  1100 , in the same direction as the stack direction. In this case, the air passages  1100  and the fuel passages  1120  formed in the fuel cell stack  1100  may be connected to air passages  151  and fuel passages  152  of the end cell heaters  1000  so as to correspond to the air passages  151  and the fuel passages  152  of the end cell heaters  1000 . In this case, cooling passages are formed between the air passages  1110  and the fuel passages  1120  in the fuel cell stack  1100 , such that a heat exchange medium (a refrigerant) may pass through the unit cells to cool the unit cells. 
         [0092]    Therefore, the end cell heaters may be installed on the fuel cell stack only by stacking the end cell heaters on outer sides of the outermost reaction cells, like stacking the unit cells constituting the fuel cell stack, and coupling the end cell heaters to the outermost reaction cells so as to closely adhere to the outermost reaction cells, and a structure for connecting the passages to each other is simple, such that the end cell heaters may be very easily installed. In addition, it is possible to prevent water in the end cells of the fuel cell stack from being frozen using the end cell heaters as described above, such that initial start ability and initial driving performance of the fuel cell may be improved. 
         [0093]    In addition, the end cell heaters  1000  according to the present invention may be disposed on both sides of the outermost portions of the fuel cell stack  1100 . Here, the end cell heaters  1000  according to the second exemplary embodiment of the present invention in which both of the air channels and the fuel channels are formed may be disposed on both sides of the fuel cell stack  1100 . Alternatively, the end cell heater  1000  according to the first exemplary embodiment of the present invention in which only the air channels are formed may be disposed on one side of the fuel cell stack  1100 , and the end cell heater  1000  according to the second exemplary embodiment of the present invention in which both of the air channels and the fuel channels are formed may be disposed on the other side of the fuel cell stack  1100 . 
         [0094]    In addition, the fuel cell  2000  may be configured to further include covers  1400  stacked on outer sides of the end cell heaters  1000 , having air passages  1410  and fuel passages  1420  formed at both sides thereof, respectively, so as to be connected to the air passages  151  and the fuel passages  152  of the end cell heaters  1000 , respectively, formed to expose the electricity collecting terminals  131  of the end cell heaters  1000  to the outside thereof, and formed of an electrical insulating material; and fastening members  1500  having both ends coupled to the covers  1400  so that the fuel cell stack  1100 , the end cell heaters  1000 , and the covers  1400  closely adhere to one another in the stack direction. 
         [0095]    That is, the covers  1400  formed of the electrical insulating material may be disposed on outer sides, in a thickness direction, of two end cell heaters  1000  disposed to be stacked, respectively, on both surfaces of the fuel cell stack  1100  in the thickness direction, and the two covers  1400 , the two end cell heaters  1000 , and the fuel cell stack  1100  may be coupled and fixed to one another so as to closely adhere to one another in the stack direction using the fastening members  1500 . In this case, the covers  1400  may have through-holes formed therein so that the electricity collecting terminals  310  may be inserted thereinto and be exposed to the outside thereof. In addition, one of the two covers  1400  may have communication holes formed therein so as to be connected to the fuel passages and the air passages, and the other of the two covers  1400  may have communication holes formed therein so as to be connected to the cooling passages. In addition, the fastening members  1500  may be formed in a plate shape elongated in the thickness direction, and both ends of the fastening members  1500  may be bent in a width direction and be coupled and fixed to the covers  1400  by fastening means such as bolts. 
         [0096]    The end cell heater for a fuel cell according to the present invention may prevent water in the reaction cell of the fuel cell stack from being frozen to improve the initial start ability and the initial driving performance of the fuel cell. 
         [0097]    In addition, the air-tightness and the pressure resistance properties of the air passages and the fuel passages formed in the end cell may be secured by the vibration fusion and the laser fusion. 
         [0098]    The present invention is not limited to the abovementioned exemplary embodiments, but may be variously applied. In addition, the present invention may be variously modified by those skilled in the art to which the present invention pertains without departing from the gist of the present invention claimed in the claims.