Abstract:
Disclosed is an electrochemical capacitor that can be reflow soldered, and wherein film package is used on the capacitor body. The container ( 20 ) of the electrochemical capacitor (ECC) stores the film package ( 11 ) of the capacitor body ( 10 ) within a storage space (SR) such that sealing sections ( 11   a - 11   c ) do not contact the inner surface of the storage space (SR). Inner material ( 30 ), which cover the sealing sections ( 11   a - 11   c ) and rear edge of the film package  11  and are adhered to the inner surface of the storage space (SR), affixing the film package ( 11 ) within the storage space (SR), are provided in a rectangular framework to the regions in the storage space (SR) of the container ( 20 ) that correspond to said sealing sections ( 11   a - 11   c ) and rear edge.

Description:
BACKGROUND 
       [0001]    The present invention relates to an electrochemical capacitor, and more specifically relates to an electrochemical capacitor enclosing a rechargeable and dischargeable electric storage element in a film package. 
         [0002]    An electrochemical capacitor such as electric dual layer capacitor, lithium ion capacitor, and redox capacitor is preferably uses a film package rather than a metal package as a capacitor body for productivity and cost benefits. Such a film package is generally formed rectangular from a laminate film including a protective layer, barrier layer, and seal layer. A typical conventional film package is formed by folding a rectangular laminate film with a predetermined size such that each half of the folded seal layer faces with one another and then heating the outer rim of the folded laminate film to fusion bond the opposing seal layers. Such film packages may also be formed from two separate rectangular laminate films with a predetermined size by overlapping the seal layers of each of the laminate films with one another and heating the outer rim of the overlapped laminate films to fusion bond the seal layers. 
         [0003]    In order to provide a compact circuit, reflow-solderable electrochemical capacitors are desired. Reflow-solderable electrochemical capacitors may be mounted on a circuit board by reflow-soldering like other types of electronic components (e.g., chip capacitors or chip registers). Reflow-soldering leads to not only a much improved productivity of mounting process but also cost reduction. 
         [0004]    However, such a film package used for an electrochemical capacitor is generally susceptible reflow-soldering process. There are several disadvantages with conventional film packages to be subjected to reflow-soldering process. Such disadvantages include leakage of electrolyte or gas out of the film package through the sealing section due to an increased inner pressure within the film package or due to softening or melting of the sealing section. 
         [0005]    In order to overcome those disadvantages, it is proposed in Japanese Patent Application Publication 2000-223085 (the “&#39;085 Publication”) to house a film package in a container to improve heat resistance of the film package. Another example to improve heat resistance of a film package is disclosed in Japanese Patent Application Publication 2009-182314 (the “&#39;314 Publication”) where a film package is covered with a rigid material. 
         [0006]    The container described in the &#39;085 Publication can delay heat conduction to the film package. However, if a temperature profile for reflow-soldering has a prolonged heating period, the temperature of the film package in the container can rise near the peak temperature (e.g., 260-280° C.), which could result in leakage of electrolyte or gas out of the film package through the sealing section as with film packages without such a container. 
         [0007]    The rigid material described in the &#39;314 Publication also can delay heat conduction to the film package. However, if a temperature profile for reflow-soldering has a prolonged heating period, the temperature of the film package in the container can rise near the peak temperature (e.g., 260-280° C.), which could generate cracks in the rigid material and damage the film package due to increased inner pressure in the film package. 
       LIST OF RELEVANT PATENT LITERATURE 
       [0008]    Patent Literature 1: Japanese Patent Application Publication 2000-223085 
         [0009]    Patent Literature 2: Japanese Patent Application Publication 2009-182314 
       SUMMARY 
       [0010]    One object of the present invention is to provide a reflow-solderable electrochemical capacitor using a film package as a capacitor body. 
         [0011]    In order to achieve the foregoing objects, an electrochemical capacitor according to one embodiment of the present invention comprises a capacitor body wherein rechargeable and dischargeable electric storage element and electrolyte are enclosed in a rectangular film package having sealing sections at least on three sides of its outer rim and one or more terminals electrically connected to the electric storage element are led out through one of the sealing sections. In one aspect, the electrochemical capacitor may include a storage space capable of housing the film package of the capacitor body. The electrochemical capacitor may include a container housing the film package in the storage space such that each of the sealing sections of the film package does not come into direct contact with the inner surface of the storage space. The electrochemical capacitor may comprise an inner material that is provided at least to the regions in the storage space of the container that correspond to said sealing sections of the film package so as to cover each of the sealing sections and be in intimate contact with to the inner surface of the storage space. An electrochemical capacitor in accordance with another aspect may include a package, an electronic component housed in the package, a container enclosing the package, and a thermosetting inner material. The package may be formed by joining a pair of sheets via corresponding thermoplastic sealing sections formed on at least the edge of their surfaces. The inner material may be disposed between at least a portion of the inner wall of the container and the sealing sections of the package so as to support the package and cover sealing sections of the package. 
         [0012]    According to one embodiment of the present invention, since the film package of the capacitor body is housed in the storage space of the container, the container may delay heat conduction to the film package, thereby mitigating the increase in the inner pressure in the film package due to the increased vapor pressure of the electrolyte. The softening of the sealing sections may also be mitigated. 
         [0013]    Since an electrochemical capacitor according to one embodiment of the present invention is configured such that each of the sealing sections of the film package of the capacitor body is covered by the inner material to reinforce the sealing capability, the covered portion may mitigate the leakage of the electrolyte or gas out of the film package through the sealing sections softened due to the increased inner pressure of the film package, even if a reflow-soldering process is carried out in accordance with a temperature profile having a prolonged heating period. 
         [0014]    According to the present invention, a reflow-solderable electrochemical capacitor using a film package as a capacitor body may be provided. 
         [0015]    The above-mentioned and other purposes, configuration characteristic, and advantageous effects of the present invention will be further described below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1(A)  shows a top view of an electrochemical capacitor according to the first embodiment of the present invention;  FIG. 1(B)  shows a front view of the electric capacitor shown in  FIG. 1(A) , and  FIG. 1(C)  shows a right side view of the electric capacitor shown in  FIG. 1(A) . 
           [0017]      FIG. 2(A)  shows a top view of the capacitor body of the electrochemical capacitor shown in  FIG. 1 ; and  FIG. 2(B)  shows a front view of the capacitor body shown in  FIG. 2(A) . 
           [0018]      FIG. 3(A)  shows a top view of a container component of the electrochemical capacitor shown in  FIG. 1 ;  FIG. 3(B)  shows a right side view of the container component shown in  FIG. 3(A) . 
           [0019]      FIG. 4  shows an expanded sectional view along with S 1 -S 1  Line in  FIG. 1(A) . 
           [0020]      FIG. 5  shows an expanded sectional view along with S 2 -S 2  Line in  FIG. 1(A) . 
           [0021]      FIGS. 6(A) and 6(B)  show one embodiment of a preferred manufacturing process of the electrochemical capacitor shown in  FIG. 1 . 
           [0022]      FIG. 7(A)  shows a top view of an electrochemical capacitor according to the second embodiment of the present invention; and  FIG. 7(B)  shows an expanded sectional view along with S 3 -S 3  Line in  FIG. 7(A) . 
           [0023]      FIG. 8(A)  shows a right side view of one of a pair of container components; and  FIG. 8(B)  shows a right side view of the other of the pair of container components. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Various embodiments of the present invention will be described below with reference to the accompanying drawings. For ease of describing, the direction toward the viewer, away from the viewer, left, right, top and bottom in  FIG. 1(A)  will be referred to as “top,” “bottom,” “front,” “rear,” “left,” and “right” respectively, while the corresponding directions in other drawings are also referred to as “top,” “bottom,” “front,” “rear,” “left,” and “right,” respectively. 
       First Embodiment 
       [0025]      FIGS. 1-6  show the first embodiment of the present invention. Electrochemical capacitor ECC shown in  FIGS. 1-6  includes capacitor body  10 , container  20 , and inner material  30 . 
         [0026]    First, with reference to  FIGS. 2 ,  4  and  5 , the capacitor body  10  will be described in greater detail. The capacitor body  10  is provided with film package  11 , rechargeable and dischargeable electric storage element  12  encapsulated in the film package  11  together with an electrolyte (not shown), and a pair of terminals  13 . The rear edge of each of the terminals  13  is electrically connected to the electric storage element  12 , and the front edge of each of the terminals  13  is lead out of the film package  11 . 
         [0027]    The film package  11  is formed rectangular from a laminate film including a protective layer, barrier layer, and a seal layer. The film package  11  is formed by folding a rectangular laminate film in half such that each half of the folded seal layers faces with one another and then heating the three sides (i.e., left, right, and front sides) of the outer rim of the folded laminate film to fusion bond the opposing parts of the seal layer. That is, the left, right, and front edges of the rectangular laminate film are heated as the laminate film is folded in half. The heating process forms belt-like sealing sections  11   a - 11   c  on the left, right, and front sides of the outer rim of the film package  11  (i.e., left, right, and front edges of the film package  11 ), respectively. The sealing section  11   c  is formed continuously with the sealing section  11   a  and sealing section  11   b . The length L 11  of the film package  11  in the front-rear direction is slightly shorter than the length L 21   a  of recess  21   a  of container component  21  (described below). The width W 11  of the film package  11  in the left-right direction is slightly smaller than the width W 21   a  of the recess  21   a  in the left-right direction. The height T 11  of the film package  11  is slightly smaller than the twice of the depth D 21   a  of the recess  21   a.    
         [0028]    The laminate film for the film package  11  is a three-layered laminate film formed by laminating a protective layer, a barrier layer and a seal layer in that order. The protective layer may be formed of thermoplastic material such as nylon or polyethylene phthalate, the thickness of which may be within 10-50 μm. The barrier layer may be formed of metal or metallic oxide such as aluminum, the thickness of which may be within 10-50 μm. The seal layer may be formed of thermoplastic material such as polypropylene or modified polypropylene, the thickness of which may be within 30-50 μm. 
         [0029]    The electric storage element  12  may be formed by laminating one or more collecting electrode layers, one or more polarizable electrode layers, and one or more separate films in a predetermined order. More specifically, the electric storage element  12  may be formed by laminating collecting electrode layer  12   a , polarizable electrode layer  12   b , separate film  12   c , polarizable electrode layer  12   d , collecting electrode layer  12   e , polarizable electrode layer  12   f , separate film  12   g , polarizable electrode layer  12   h , and collecting electrode layer  12   i , from top to bottom in that order, such that adjacent layers each comes into intimate contact with one another. Disposed integrally on the right side of the front edge of the collecting electrode layer  12   e , which exists at the center in the laminating direction, is a rectangular terminal connection  12   e   1 . In addition, terminal connections (reference number not shown) are integrally provided on the left side of the front edge of each of the collecting electrode layer  12   a  and  12   i . The electric storage element  12  is enclosed in the film package  11  together with an electrolyte (not shown) such that each of the terminal connections faces forwardly. 
         [0030]    The collecting electrode layers  12   a ,  12   e  and  12   i  of the collecting electrode layer, polarizable electrode layer, and separate film for the electric storage element  12  may be formed of conductive material such as aluminum or platinum, the thickness of which may be within 5-50 μm. The polarizable electrode layers  12   b ,  12   d ,  12   f  and  12   h  may be formed of active material such as PAS (polyacenic organic semiconductor) or active carbon, the thickness of which may be within 10-50 μm. The separate films  12   c  and  12   g  may be formed of ion conductive film such as cellulosic film or plastic film, the thickness of which may be within 10-50 μm. 
         [0031]    A pair of terminals  13  may be formed in a strip shape. The length of each of the terminals  13  is larger than its width W 13  in the left-right direction. The rear edge of one of the terminals  13  is electrically connected to the terminal connection  12   e   1  of the collecting electrode layer  12   e  of the electric storage element  12  using, for example, spot welding. Similarly, the rear edge of the other of the terminals  13  is electrically connected to the terminal connection of the collecting electrode layers  12   a  and  12   i . The front edges of each of the terminals  13  are lead out of the film package  11  through the sealing section  11   c  formed on the front side of the film package  11  in parallel with one another. 
         [0032]    The terminals  13  may be formed of conductive material such as aluminum or platinum, the thickness of which may be within 50-100 μm. The tip ends of each of the terminals  13  is provided with metal film which may be plated with metal such as tin or gold. 
         [0033]    Now, a preferred manufacturing method of the capacitor body  10  shown in  FIG. 2  will be described. First, a rectangular laminate film with a predetermined size is placed such that its seal layer faces upwardly. Next, electric storage element  12  provided with a pair of terminals  13  are placed on the seal layer such that each of the terminals  13  projects from the front or rear end of the rectangular laminate film. Then, the rectangular laminate film is folded in half along the center in the front-rear direction thereof such that each half of the folded seal layer faces with one another. Subsequently, the left and right parts of the outer rim (i.e., the left and right edges of the rectangular laminate film) are heated using an appropriate heating device to fusion bond the each halve of the folded seal layer so as to form left sealing section  11   a  and right sealing section  11   b . That heating process produces a film package in pouched-shaped without having front sealing section  11   c . Then, an electrolyte is poured into the thus-prepared pouched-shape film package through the opening formed on the front side of the film package. Next, the front portion of the outer rim (i.e., the front edge of the rectangular laminate film) using a similar heating device as described above to fusion bond the each halve of the folded seal layer so as to form front sealing section  11   c . The electrolyte may be a liquid electrolyte prepared by mixing triethylmethylammonium fluoroborate with a propylene carbonate solvent or a gelatinous electrolyte prepared by mixing, for example, polyacrylonitrile with said liquid electrolyte. Thus, each of the terminals  13  is disposed between the upper and lower halves of the seal layer on the sealing section  11   c  and the front edges of each of the terminals  13  are lead out of the film package  11 . 
         [0034]    As shown in  FIG. 5 , the left sealing section  11   a  and right sealing section  11   b  is formed in U shape by first bending the planar portion, which is formed by fusion bonding the opposing halves of the seal layer as noted above, into U shape and then heating the bent portion. Thus prepared U shape structure may provide improved sealing performance. As shown in  FIG. 4 , the terminals  13  prevent the front sealing section  11   c  from being bent like the left sealing section  11   a  and right sealing section  11   b . In one embodiment, auxiliary seal layer (not shown) may be provided around the front sealing section  11   c  on the terminals  13 , thereby providing improved sealing performance of the front sealing section  11   c . Such an auxiliary seal layer may prevent the terminals  13  from coming into contact with the barrier layer due to melt flow of the seal layer. 
         [0035]    Next, with reference to FIGS.  1  and  3 - 5 , the container  20  will be further described. The container  20  may be formed by combining two container components  21  as shown in  FIG. 3 . 
         [0036]    The container component  21  includes rectangular bottom wall, front wall, rear wall, left wall and right wall, which are formed integrally with one another, as well as recess  21   a  formed rectangular in top view. As noted above, the length L 21   a  of the recess  21   a  in the front and rear direction is slightly longer than the corresponding length L 11  of the film package  11  of the capacitor body  10 , the width W 21   a  is slightly larger than the width W 11  of the film package  11 , and the depth D 21   a  is slightly larger than the half of the height T 11  of the film package  11 . Vent  21   b  passing through the bottom wall is formed approximately at the center of the bottom wall (bottom wall of the recess  21   a ) of the container component  21 . In addition, a pair of rectangular cutouts  21   c  is formed on the front wall upper surface of the container component  21  apart from each other by the distance corresponding to the distance between the pair of terminals  13 . Each of the cutouts  21   c  has width W 21   c  in the left-right direction slightly larger than the width  13  of the corresponding terminals  13  of the capacitor body  10 . 
         [0037]    The container component  21  may be formed of thermosetting plastics such as polyimide, epoxy resin or composite material thereof reinforced with glass fiber etc. (e.g., FRP), the thickness of the bottom wall, front wall, rear wall, left wall and right wall may be each within 100-300 μm. The container component  21  formed of polyimide or thermosetting plastics may provide improved heat resistance and higher stiffness than the film package  11  of the capacitor body  10 . In addition, the container component  21  may be manufactured at low cost by using plastics molding. The diameter of the vent  21   b  is preferably within 0.3-1.0 mm so as to prevent inflow of heat. 
         [0038]    The container  20  of  FIGS. 4 and 5  may be formed by combining a pair of container components  21  such that the corresponding apertures and corresponding rectangular cutouts  21   c  thereof are aligned with each other. Thus combined container components  21  are joined by inner material  30  (described below), and, as such, rectangular parallelepiped storage space SR is formed within the container  20 . The length of the storage space SR in the front-rear direction is represented by L 21   a  and the width thereof in the left-right direction is represented by W 21   a . The depth of the storage space SR is twice as D 21   a . The aligned rectangular cutouts  21   c  form a pair of lead-out holes (reference number not shown) for the corresponding terminals  13  on the front wall of the container  20 . 
         [0039]    As shown in  FIGS. 4 and 5 , the storage space SR of the container  20  houses the film package  11  of the capacitor body  10  and the butt ends of the terminals  13 , the tip ends of each of the terminals  13  is exposed to the outside of the container  20  through the corresponding lead-out holes defined by the rectangular cutouts  21   c.    
         [0040]    As noted above, the length L 21   a  of the storage space SR of the container  20  in the front-rear direction may be slightly larger than the length L 12  of the film package  11 , the width W 21   a  thereof in the left-right direction may be slightly larger than the width W 12  of the film package  11 , the depth D 21   a  thereof may be slightly larger than the height T 12  of the film package  11 . The thus formed container  20  with the aforementioned size and shape may easily house the film package  11  of the capacitor body  10  within the storage space SR. 
         [0041]    As shown in  FIGS. 4 and 5 , with the film package  11  fixed approximately at the center of the storage space SR using inner material  30  (described below), gap Ga is defined between the front edge of the film package  11  (front edge of the front sealing section  11   c ) and the front wall inner surface of the container  20 , gap Gb is defined between the rear edge of the film package  11  and the rear wall inner surface of the container  20 , gap Gc is defined between the left edge of the film package  11  (left edge of the left sealing section  11   a ) and the left wall inner surface of the container  20 , and gap Gd is defined between the right edge of the film package  11  (left edge of the right sealing section  11   b ) and the right wall inner surface of the container  20 . Thus, the film package  11  is housed in the storage space SR such that the sealing sections  11   a - 11   c  and rear edge of the film package  11  does not come into direct contact with the inner surface of the container  20 . 
         [0042]    In addition, clearance CLu is defined between the upper surface of the film package  11  and the top wall inner surface of the container  20 , and clearance CLd is defined between the bottom surface of the film package  11  and the bottom wall inner surface of the container  20 . Thus, the parts of the top and bottom surfaces of the film package  11  on which the inner material  30  is not provided does not come into contact with the inner surface of the container  20 . 
         [0043]    Moreover, the vent  21   b  formed on the top wall of the container  20  faces with the parts of the upper surface of the film package  11  on which the inner material  30  is not provided through the clearance CLu, the vent  21   b  formed on the bottom wall of the container  20  faces with the parts of the bottom surface of the film package  11  on which the inner material  30  is not provided through the clearance CLd. Thus, the clearances CLu and CLd formed in the storage space SR are each connected to the ambient air through the corresponding vent  21   b.    
         [0044]    Next, with reference to  FIGS. 1 ,  4  and  5 , the inner material  30  will be described in greater detail. The inner material  30  is provided to join the combined upper and lower container components  21  and fix the film package  11  of the capacitor body  10  within the storage space SR of the container  20 . 
         [0045]    The inner material  30  may be formed of thermosetting plastics such as polyimide, epoxy resin, or composite material thereof reinforced with glass fiber etc (e.g., FRP). The inner material  30  thus formed of polyimide or other types of thermosetting plastics may provide the film package  11  of the capacitor body  10  having improved heat resistance and higher stiffness. In addition, the inner material  30  enables the pair of container components  21  to be easily combined using a simple heating process to fix the film package  11 . 
         [0046]    As can be seen in  FIGS. 4 and 5 , the inner material  30  is formed in rectangular frame shape along the rear edge and sealing sections  11   a - 11   c  of the film package  11  in the storage space SR of the container  20 . 
         [0047]    In more detail, the part of the inner material  30  disposed on the front side of the film package  11  is in intimate contact with the bottom wall inner surface and front wall inner surface of the lower container component  21  as well as with the top wall inner surface and front wall inner surface of the upper container component  21  so as to cover the front sealing section  11   c  of the film package  11 , the part of front side of the film package  11  adjacent inside to the front sealing section  11   c , and the butt ends of each of the terminals  13 . The part of the inner material  30  disposed on the rear side of the film package  11  is in intimate contact with the bottom wall inner surface and rear wall inner surface of the lower container component  21  as well as the top wall inner surface and rear wall inner surface of the upper container component  21  so as to cover the rear side of the film package  11 . In addition, the part of the inner material  30  disposed on the left side of the film package  11  is in intimate contact with the bottom wall inner surface and left wall inner surface of the lower container component  21  as well as the top wall inner surface and left wall inner surface of the upper container component  21  so as to cover the left sealing section  11   a  of the film package  11  and parts the left side of the film package  11  adjacent inside to the left sealing section  11   a . Furthermore, the part of the inner material  30  disposed on the right side of the film package  11  is in intimate contact with the bottom wall inner surface and right wall inner surface of the lower container component  21  as well as with the top wall inner surface and right wall inner surface of the upper container component  21  so as to cover the right sealing section  11   b  of the film package  11  and the parts of the right side of the film package  11  adjacent inside to the right sealing section  11   b . Thus, the upper and lower container components  21  of the container  20  is joined by the inner material  30  and the film package  11  of the capacitor body  10  stored in the storage space SR of the container  20  is fixed by the inner material  30  within the storage space SR. 
         [0048]    Now, with reference to  FIG. 6 , a preferred manufacturing method of the electrochemical capacitor ECC shown in  FIG. 1  will be described. First, capacitor body  10  shown in  FIG. 2  and container component  21  shown in  FIG. 3  are prepared. 
         [0049]    Next, as shown in  FIG. 6(A) , a fluent inner material M 30  is applied to the recess  21   a  of the lower container component  21  using an suitable coating device. The thus applied fluent inner material M 30  is pushed downwardly by the film package  11  of the capacitor body  10  to spread toward the vent  21   b  (as shown in  FIG. 6(A)  by two-dot chain line). The amount of the fluent inner material M 30  to be applied may be adjusted taking account of such spread of the inner material M 30 . 
         [0050]    Subsequently, as shown in  FIG. 6(B) , the film package  11  of the capacitor body  10  is inserted in the recess  21   a  with the fluent inner material M 30 , each of the terminals  13  is inserted into the rectangular cutouts  21   c ,  21   c , respectively. The film package  11  of the capacitor body  10  is disposed around the center of the recess  21   a  such that the gaps Ga, Gb, Gc and Gd are formed as shown in  FIGS. 4 and 5 . 
         [0051]    Next, as with the lower container component  21  shown in  FIG. 6(A) , the fluent inner material M 30  is applied to the recess  21   a  of the upper container component  21  and the upper container component  21  is combined with the lower container component  21  such that the aperture of the recess  21   a  of the upper container component  21  is aligned with that of the recess  21   a  of the lower container component  21  and the rectangular cutouts  21   c  of the upper container component  21  is aligned with the corresponding rectangular cutouts  21   c  of the lower container component  21 . 
         [0052]    Next, the thus combined upper and lower container components  21  is left at room temperature for a predetermined period to cure the fluent inner material M 30 . In case that the fluent inner material M 30  is epoxy resin, the container components  21  is left at temperature of 100-150° C. 
         [0053]    In the event that the fluent inner material M 30  is leaked out of the container components  21  during the process of combining the lower container component  21  with the upper container component  21 , it is preferable that the leaked portion of the fluent inner material M 30  is eliminated before or after the curing of the fluent inner material M 30 . 
         [0054]    Next, the behavior of the electrochemical capacitor ECC shown in  FIG. 1  during mounting on a circuit board will be described, where the mounting process is carried out in reflow-soldering as with other electronic components such as chip capacitors or chip registers. 
         [0055]    As with reflow-soldering for other electronic components, solder cream may be applied as necessary to the folded electrochemical capacitor ECC. Each of the terminals  13  of the folded electrochemical capacitor ECC is placed on corresponding pads via solder cream, and then the circuit board provided with the electrochemical capacitor ECC is loaded in a reflow furnace. 
         [0056]    Since the film package  11  of the capacitor body  10  of the electrochemical capacitor ECC according to one embodiment of the present invention is housed within the storage space SR of the container  20 , heat conduction to the film package  11  may be delayed by the container  20 , thereby suppressing the increase of the inner pressure inside the film package  11  due to increased vapor pressure of the electrolyte and thereby preventing the seal portion of each of the sealing sections  11   a - 11   c  from softening using a temperature profile for reflow-soldering having a relatively shorter heating period. In one embodiment, the container  20  is formed of polyimide or thermosetting plastics having heat resistance, thereby achieving further suppressing the increase of the inner pressure of the film package  11  and further preventing the softening of the seal portions. 
         [0057]    If the reflow-soldering process is carried our in accordance with a temperature profile having a prolonged heating period, the temperature of the film package  11  may increase up to the peak or near peak temperature (e.g., 260-280° C.). The increase of the temperature of the electrolyte may cause the vapor pressure of the electrolyte to increase accordingly and thereby may cause the inner pressure of the film package  11  to increase and cause the seal portions of the sealing sections  11   a - 11   c  to soften. However, since the electrochemical capacitor ECC according to one embodiment of the present invention is configured such that each of the sealing sections  11   a - 11   c  of the film package  11  of the capacitor body  10  is covered by the inner material  30  to reinforce the sealing capability, the covered portion may mitigate the leakage of the electrolyte or gas out of the film package  11  through the sealing sections  11   a - 11   c  even if the inner pressure of the film package  11  increases or the seal portions of the sealing sections  11   a - 11   c  soften. In addition, since the inner material  30  is formed of polyimide or thermosetting plastics, the inner material  30  may provide further improvement in heat resistance performance and stiffness to further suppress the leakage of the electrolyte or gas. Furthermore, since the gap Ga is formed between the front edge of the film package  11  (front edge of the front sealing section  11   c ) and the front wall inner surface of the container  20 , the gap Gc is formed between the left edge of the film package  11  (left edge of the left sealing section  11   a ) and the left wall inner surface of the container  20 , and the gap Gd is formed between the right edge of the film package  11  (left edge of the right sealing section  11   b ) and the right wall inner surface of the container  20 , sufficient amount of inner material  30  may be disposed within those gaps Ga, Gc and Gd so as to robustly cover each of the sealing sections  11   a - 11   c , thereby mitigating the leakage of the electrolyte or gas. Furthermore, not only each of the sealing sections  11   a - 11   c  but also the parts of the film package  11  adjacent inwardly to each of the sealing sections  11   a - 11   c  may be covered by the inner material  30 , thereby further mitigating the leakage of the electrolyte or gas. 
         [0058]    If the outermost layer of the film package  11  of a conventional electrochemical capacitor is formed of water-retentive material such as nylon, water vapor generated from the outermost layer may increase the inner pressure of the storage space SR of the container  20  to generate a sufficient pressure to crush the film package  11  and electric storage element  12 . On the other hand, since the electrochemical capacitor ECC according to one embodiment of the present invention is configured such that the vent  21   b  of the top wall of the container  20  faces the parts of the upper surface of the film package  11  on which the inner material  30  is not provided through the clearance CLu and the vent  21   b  of the bottom wall of the container  20  faces with parts of the bottom surface of the film package  11  on which the inner material  30  is not provided through the clearance CLd, the water vapor generated from the outermost layer of the film package  11  may be easily released through the vents  21   b  to the ambient air, thereby mitigating the increase of the inner pressure in the storage space SR. Accordingly, it may be prevented that the increased inner pressure in the storage space SR generates a pressure to crash the film package  11  and electric storage element  12 . If the outermost layer of the film package  11  generates no or little water vapor, then the vents  21   b  may release the expanded air in the storage space SR of the container  20  to the ambient air, thereby preventing excessive increase in the inner pressure in the storage space SR. 
         [0059]    Thus, the electrochemical capacitor ECC in accordance with one embodiment of the present invention may be mounted on a circuit board by reflow soldering, as with other types of electronic components, without causing such problems as caused by the conventional electro chemical capacitors. Accordingly, an improved productivity and reduced production cost may be achieved in the mounting process of electrochemical capacitors. 
       Second Embodiment 
       [0060]      FIG. 7  shows the second embodiment of the present invention. The electrochemical capacitor ECC shown in  FIG. 7  differs from that of the first embodiment in that the inner material  30 ′ of the second embodiment is formed in C shape along with each of the sealing sections  11   a - 11   c  of the film package  11  in the storage space SR of the container  20 . 
         [0061]    The part of the inner material  30 ′ disposed on the front side of the film package  11  is in intimate contact with the bottom wall inner surface and front wall inner surface of the lower container component  21  as well as with the top wall inner surface and front wall inner surface of the upper container component  21  so as to cover the front sealing section  11   c  of the film package  11 , the part of front side of the film package  11  adjacent inside to the front sealing section  11   c , and the butt ends of each of the terminals  13 . The part of the inner material  30 ′ disposed on the left side of the film package  11  is in intimate contact with the bottom wall inner surface and left wall inner surface of the lower container component  21  as well as the top wall inner surface and left wall inner surface of the upper container component  21  so as to cover the left sealing section  11   a  of the film package  11  and the parts the left side of the film package  11  adjacent inside to the left sealing section  11   a . In addition, the part of the inner material  30 ′ disposed on the right side of the film package  11  is in intimate contact with the bottom wall inner surface and right wall inner surface of the lower container component  21  as well as with the top wall inner surface and right wall inner surface of the upper container component  21  so as to cover the right sealing section  11   b  of the film package  11  and the parts of the right side of the film package  11  adjacent inside to the right sealing section  11   b . Furthermore, clearance CLb is defined in rear of the film package  11  in such a manner as to connect to the clearances CLu and CLd since the inner material  30 ′ is not disposed in that area. 
         [0062]    As with the first embodiment, the inner material  30 ′ may join the combined upper and lower container components  21  and fix the film package  11  of the capacitor body  10  within the storage space SR of the container  20 . The electrochemical capacitor ECC shown in  FIG. 7(A)  may also achieve various advantageous effects in the process of mounting electronic component on a circuit board by reflow-soldering as with the first embodiment. 
       Other Embodiments 
       [0063]    The size of each of the gaps Ga, Gb, Gc and Gd may differ from each other. 
         [0064]    The size of each of the clearances CLu and CLd may also differ from each other. The size of each of the clearances CLu and CLd may be zero to the extent that the upper and bottom surfaces of film package  11  is not in intimate contact with the corresponding top wall inner surface and bottom wall inner surface of the container  20  and film package  11  so that water vapor may be smoothly released to the ambient air. 
         [0065]    Two or more vents  21   b  may be provided on each of the container components  21 . Since an increased number of vents  21   b  may result in inflow of heat, each of the diameters of the multiple vents  21   b  may be formed smaller than that of the single vent  21   b  as described in the first and second embodiments. 
         [0066]    Although the first and second embodiments each describes the two separate container components  21  shown in  FIG. 3  to be combined to form the container  20 , a pair of container components  22  and  23 , which have different shapes from each other as shown in  FIGS. 8(A) and 8(B) , may be used to form the container  20 . 
         [0067]    The container component  22  shown in  FIGS. 8(A) and 8(B)  is formed in box shape including rectangular bottom wall, front wall, rear wall, left wall, and right wall. The container component  22  is formed rectangular in top view and provided with recess  22   a  having an aperture on its top surface. The length of the recess  22   a  in the front-rear direction is same as L 21   a  shown in  FIG. 3 , the width of the recess  22   a  is same as W 21   a  shown in  FIG. 3 , and the depth D 22   a  is same as twice as D 21   a  shown in  FIG. 3 . The size of each of the rectangular cutouts  22   c  in the left-right direction is same as W 13  as shown in  FIG. 3 , and the depth D 22   c  of each of the rectangular cutouts  22   c  is same as the sum of D 21   c  and D 21   a  shown in  FIG. 3 . 
         [0068]    The container component  23  may be configured by eliminating the front, rear, left, and right walls from the container component  21  shown in  FIG. 3 . The container component  23  may be rectangular in top view. The container component  23  includes a pair of rectangular projections  23   a ,  23   a  formed integrally on the front edge bottom surface. The projections  23   a ,  23   a  are configured to be inserted into the corresponding rectangular cutouts  22   c ,  22   c . The height of each of the projections  23   a ,  23   a  is same as D 21   a  shown in  FIG. 3 . Vent  22   b  is formed approximately at the center of the bottom wall of the container component  22  (bottom wall of the recess  22   a ). Similarly, a vent  23   b  is formed approximately at the center of the container component  23 . As noted above, two or more vents  22   b  and/or  23   b  may be provided. 
         [0069]    A container having the same outer shape as the container  20  of the first and second embodiments may be obtained by combining the container component  22  and  23 . 
         [0070]    Although the film package  11  of the first and second embodiments may be obtained by folding in half a rectangular laminate film with a predetermined size such that each half of the folded seal layer faces one another and then heating three sides of the outer rim (i.e., left, right, and front sides) to fusion bond the opposing halves of the seal layer with each other, the film package  11  according to another embodiment of the present invention may be formed by overlapping two separate rectangular laminate films with a predetermined size such that the seal layers thereof face with each other and then heating the four sides of the outer rim (i.e., left, right, front, and rear sides) to fusion bond the seal layers. Thus prepared film package is provided with four belt-like seals continuously on each of the left, right, front and rear sides of the outer rim, and inner material  30  may be disposed on the film package as with the first embodiment in order to achieve similar advantageous effects to the electrochemical capacitor ECC of the first embodiment. 
       INDUSTRIAL APPLICABILITY 
       [0071]    The present invention has industrial applicability to provide various electrochemical capacitors such as electric dual layer capacitors, lithium ion capacitors, or redox capacitors. 
       LIST OF REFERENCE NUMBERS 
       [0000]    
       
         ECC . . . Electrochemical capacitor 
           10  . . . Capacitor body 
           11  . . . Film package 
           11   a ,  11   b ,  11   c  . . . Seal 
           12  . . . Electric storage element 
           13  . . . Terminal 
           20  . . . Container 
           21 ,  22 ,  23  . . . Container component 
           21   b ,  22   b ,  23   b  . . . Vent 
         SR . . . Storage space 
           30 ,  30 ′. . . Inner material 
         Ga, Gb, Gc, Gd . . . Gap 
         CLu, CLd, CLb . . . Clearance