Abstract:
[Object] It is an object to provide an injection method for injecting an electrolyte and an electrolyte injection apparatus which allow the electrolyte to be injected and filled into an electrode assembly within an outer can with favorable permeation, thereby easily manufacturing an electrolyte secondary battery having favorable cycle characteristics at good yield. 
     [Solution] A solution injection nozzle  10  is inserted into a solution injection hole  101  of an outer can  100  in which an electrode assembly  110  is stored, and the solution injection hole  101  is hermetically sealed by a pressure reducing pad  11  provided so as to surround a periphery of the solution injection nozzle  10.  An inside of the outer can  100  is made into a negative pressure through the pressure reducing pad  11,  and an electrolyte L is supplied from the solution injection nozzle  10  into the outer can  100.  The outer can  100  is rotated with the solution injection nozzle  10  as a rotation center.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an injection method for injecting an electrolyte for a secondary battery, and an apparatus therefor. 
       BACKGROUND ART 
       [0002]    At present, improvements to secondary batteries such as lithium-ion secondary battery are being actively made, since it is possible to achieve a high voltage and a high energy density with a secondary battery. Main components of a secondary battery are an assembly of a power generating element body composed of a pair of electrodes, namely, a positive electrode and a negative electrode, and a separator which separates both electrodes to prevent a short circuit therebetween, an electrolyte filled in the power generating element body, and an outer can which stores these components therein. 
         [0003]    A lithium secondary battery that has been put to practical use is manufactured through the following procedure. Both positive and negative electrodes and a separator are inserted into an outer can body in a state of being wound in an overlap manner or being laminated on each other, and an opening of the outer can body is closed with a cap. Thereafter, an electrolyte is injected through an injection hole provided in the cap, and then the injection hole is sealed. 
         [0004]    When the electrolyte is filled into the outer can, the electrolyte has to infiltrate into the entirety of the electrode assembly obtained by assembling the positive and negative electrodes and the separator. However, each of the gaps between the positive and negative electrodes and the separator in the electrode assembly which is a wound body or laminated body of the positive and negative electrodes and the separator which are in the form of sheet is very narrow, and it takes time until air having entered the gaps is replaced with the electrolyte that has newly infiltrated into the gaps and the electrolyte completely permeates and infiltrates into the gaps. Thus, it is necessary to inject the electrolyte, to store the outer can that remains open in a wide clean room that is adjusted into an optimum environment by its humidity and temperature being managed, for causing the electrolyte to gradually infiltrate into the gaps in the electrode assembly, and to cause the outer can to stand still until the replacement is completed. This method has a problem that it takes an excessive amount of time to cause the electrolyte to permeate into the electrode assembly and the electrolyte cannot be efficiently filled therein. 
         [0005]    Thus, Patent Literature 1 has been proposed as improvement of the electrolyte filling method. A method described in Patent Literature 1 is a method in which the pressure in an outer can in which an electrode assembly is stored is reduced and an electrolyte is supplied under the reduced pressure, and the electrolyte is sucked by the pressure-reduced outer can as in a dropper, and injected and filled therein. In this method, the electrolyte is sucked into the outer can that is kept at a negative pressure, and thus the injection filling time is significantly shortened as compared to the conventional replacement method. However, micro air bubbles remaining in the gaps in the electrode assembly are increased in volume while the pressure is reduced, and a state is kept in which the air bubbles are stuck in the gaps. Thus, the electrolyte does not reach this portion, and a state is provided in which small bores are present. Accordingly, this method still is problematic for a demand for dense filling of the electrolyte. 
         [0006]    Furthermore, as a solution to the problem of this method, a method described in Patent Literature 2 has been proposed. In this method, after the inside of an outer can is made into a negative pressure by suction, the electrolyte is injected. In a state of the electrolyte being injected, pressure is applied to decrease the volumes of micro air bubbles remaining stuck in the gaps, such that it is made easy for the air bubbles to float up from the gaps, whereby the degree of filling is increased. The pressure reduction and the pressure application are repeated. By this method, the injection rate is further increased. However, the buoyancy of the micro air bubbles is merely used, and there are micro air bubbles that do not float up due to the surface tension thereof or the like. Thus, the demand for dense filling of the electrolyte cannot be fully met. Other than the above, a filling method with only pressure application (Patent Literature 3) and a method using a centrifugal force (Patent Literature 4) have also been proposed. 
       CITATION LIST 
     Patent Literature 
       [0007]    [PTL 1] Japanese Laid-Open Patent Publication No. 09-102443 
         [0008]    [PTL 2] Japanese Laid-Open Patent Publication No. 09-099901 
         [0009]    [PTL 3] Japanese Laid-Open Patent Publication No. 2002-274504 
         [0010]    [PTL 4] Japanese Laid-Open Patent Publication No. 2004-327167 
       DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
       [0011]    The above-described pressure reducing method or the above-described method using pressure reduction and pressure application in combination is unsatisfactory in terms of mass production since it is problematic in terms of stability or reliability as described above. In addition, for an electrolyte battery of such a type, densification of the electrode assembly (increasing the degree of filling of an active material or tightening winding/lamination) is promoted with compactification of the components or an increase in the capacity, and thus there is a tendency that it is hard for the electrolyte to permeate. Poor permeation of the electrolyte increases the time taken to inject and fill the electrolyte, resulting in deterioration of the productivity. Moreover, with insufficiency of the amount of the injected and filled electrolyte, a problem, such as causing a decrease in cycle characteristics of an electrolyte type battery, is concerned. 
         [0012]    In the method using a centrifugal force, after solution injection, a solution injection nozzle is detached, and then dense filling of the electrolyte is conducted by rotating the outer can. Thus, it is necessary to repeat the solution injection process and the dense filling process, and hence the manufacturing process is complicated and there is a problem that it takes time for the filling. In addition, the outer can is merely rotated in a state where the electrolyte has been dropped, and thus the electrolyte does not positively infiltrate into the micro gaps, and there is also a problem that air bubbles stuck in the micro gaps are unlikely to be removed and insufficiency of the amount of the injected and filled electrolyte still remains. 
         [0013]    The present invention has been made by coping with the above-described circumstances, and an object of the present invention is to provide an injection method for injecting an electrolyte and an electrolyte injection apparatus which allow the electrolyte to be injected and filled into an electrode assembly within an outer can with favorable permeation, thereby easily manufacturing an electrolyte secondary battery having favorable cycle characteristics at good yield. 
       Solution to the Problems 
       [0014]    An invention according to an injection method for injecting an electrolyte L of claim  1  is characterized in “inserting a solution injection nozzle  10  into a solution injection bole  101  of an outer can  100  in which an electrode assembly  110  is stored, and hermetically sealing the solution injection hole  101  by a pressure reducing pad  11  provided so as to surround a periphery of the solution injection nozzle  10 ; making an inside of the outer can  100  into a negative pressure through the pressure reducing pad  11 , and supplying the electrolyte L from the solution injection nozzle  10  into the outer can  100 ; and rotating the outer can  100  with the solution injection nozzle  10  as a rotation center”. 
         [0015]    Here, the outer can  100  is rotated simultaneously with or after start of suction of air within the outer cart  100 , and solution injection is conducted simultaneously with the suction or after start of the suction. The electrolyte L that has been injected and entered a gap in the electrode assembly  110  within the outer can  100  by the inside of the outer can  100  being made into the negative pressure by the suction is pushed to flow toward a lateral side of the outer can  100  by a centrifugal force generated by the rotation, thereby forcibly pushing out micro air bubbles having entered the same gap, toward the lateral side, and the electrolyte L spreads to push out the pushed-out micro air bubbles to above the electrode assembly  110 . Then, the pushed-out micro air bubbles are continuously sucked through the pressure reducing pad  11 . In addition, since gas occluded in the electrolyte L is also simultaneously and continuously sucked through the pressure reducing pad  11 , the electrolyte L smoothly infiltrates into micro gaps between positive and negative electrodes and a separator, dense filling is quickly conducted in the solution injection, and the solution injection operation ends substantially at the same time with completion of the solution injection. It should be noted that the outer can  100  rotates with the solution injection nozzle  10  as a rotation center, and thus the solution injection hole  101  does not impede the solution injection operation even when the solution injection hole  101  is located in any portion of the outer can  100 . 
         [0016]    A injection method according to claim  2  is characterized in that “the solution injection nozzle  10  is inserted into the solution injection hole  101  and solution injection is conducted after reduction of a pressure in the outer can  100  through the pressure reducing pad  11 ” in the injection method according to claim  1 . An injection inetwd according to claim  3  is characterized in that “pressure reduction is continuously conducted during solution injection from the solution injection nozzle  10 ” in injection method according to claim  1  or  2 . In the injection method according to claim  2 , since the solution injection nozzle  10  is not inserted into the solution injection hole  101  at the time of pressure reduction, the solution injection hole  101  is widely open at the time of pressure reduction, and hence it is possible to increase a pressure reducing rate. When the pressure reduction is continuously conducted also during the solution injection as in claim  3 , it is possible to continuously suck and remove air remaining in the outer can  100  and gas occluded in the electrolyte L, and thus it is possible to more quickly and densely fill the electrolyte L. 
         [0017]    Claim  4  is an apparatus for executing the electrolyte injection methods according to claims  1  to  3 , including: 
         [0018]    a rotating platform  1  configured to retain an outer can  100  in which an electrode assembly  110  is stored and to rotate with a solution injection hole  101  of the outer can  100  as a rotation center; 
         [0019]    a solution injection device  5  including a solution injection nozzle  10  which is provided so as to coincide with the rotation center of the rotating platform  1  and is configured to supply an electrolyte L into the outer can  100  when being inserted into the solution injection hole  101  of the outer can  100 , and a pressure reducing pad  11  which is provided so as to surround a periphery of the solution injection nozzle  10  and is configured to adhere to a portion surrounding the solution injection hole  101  by suction and to make an inside of the outer can  100  into a pressure-reduced state at a time of solution injection; 
         [0020]    a lifting/lowering device  20  configured to cause the rotating platform  1  and the solution injection device  5  to be relatively close to each other or separated from each other and to press the pressitre reducing pad  11  against the portion surrounding the solution injection hole  101  to hermetically seal the solution injection hole  101  when the rotating platform  1  and the solution injection device  5  are caused to be close to each other; and 
         [0021]    a rotary drive device  30  configured to rotate the outer can  100 , 
         [0022]    Claim  5  is characterized in the apparatus of claim  4  “further including a nozzle insertion/detachment mechanism  40  configured to bring the pressure reducing pad  11  into contact with the portion surrounding the solution injection hole  101  of the outer can  100 , to retain the solution injection nozzle  10  outside the solution injection hole  101  during a period front start of reduction of is pressure in the outer can  100  to a time of the pressure being reduced to a predetermined pressure, and to insert the solution injection nozzle  10  into the solution injection hole  101  after reaching the predetermined pressure”. 
       Advantageous Effects of the Invention 
       [0023]    According to the present invention, due to the synergistic effect of the reduction of the pressure in the outer can  100  by suction and the centrifugal force generated by the rotation with the solution injection nozzle  10  as a rotation center, the electrolyte L injected into the outer can  100  rapidly infiltrates into a very narrow gap in the electrode assembly  110 , and it is possible to complete the solution injection in a short time. In addition, the rotation with the solution injection nozzle  10  as a rotation center is possible even when the solution injection hole  101  is located in any portion of the outer can  100 , and the solution injection nozzle  10  can be used for all types of outer cans  100 . 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a schematic plan view of an apparatus according to the present invention. 
           [0025]      FIG. 2  is a partial cross-scctional view of a principal part of a first embodiment of the according to the present invention. 
           [0026]      FIG. 3  is an enlarged cross-sectional view of a solution injection device in  FIG. 1 . 
           [0027]      FIG. 4(A)  is a partial front view before insertion of an outer can,  FIG. 4  (B) is is partial front view immediately after the insertion of the outer can,  FIG. 4  (C) is a partial front view when a solution injection nozzle is inserted into the outer can, and  FIG. 4  (D) is a partial front view when an electrolyte is being injected from the solution injection nozzle. 
           [0028]      FIG. 5  is an enlarged cross-sectional view of a solution injection nozzle insertion/detachment mechanism of a second embodiment according to the present invention. 
           [0029]      FIG. 6  is an enlarged cross-sectional view before insertion of a solution injection nozzle of the second embodiment according to the present invention. 
           [0030]      FIG. 7  is an enlarged cross-sectional view after the insertion of the solution injection nozzle in  FIG. 6 . 
           [0031]      FIG. 8  is a partial cross-sectional view of a principal part of a third embodiment of the apparatus according to the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0032]    Hereinafter, a first embodiment of the present invention will be described with reference to  FIGS. 1 to 4 . An outer can  100  which is a workpiece applied to the present invention is a can which has an electrode assembly  110  stored therein and in which a solution injection hole  101  is provided in an upper surface thereof. The diameter of the solution injection hole  101  is generally determined, but the position thereof is varied depending on the type of a product. In addition, the shape and the size of the outer can  100  are varied depending on the type. The outer can  100  also serves as a negative electrode terminal, and is, for example, a can which is made of stainless copper and has a bottomed circular tube or square tube shape. The stored electrode assembly  110  is composed of positive and negative electrodes and a separator which separates these electrodes. These components have a sheet shape, and the electrode assembly  110  is a laminated body of the sheet-shaped positive electrode, the sheet-shaped separator, and the sheet-shaped negative electrode or a wound body obtained by spirally winding a laminated body of the sheet-shaped positive electrode, the sheet-shaped separator, and the sheet-shaped negative electrode. Very narrow gaps are present between these components, and an electrolyte L is to be filled within the gaps. 
         [0033]    This apparatus includes an apparatus main body A which intermittently rotates, a disk base  2  provided on the apparatus main body A, a plurality of arms  3  (four arms in the present embodiment) extending above the disk base  2  and radially from the apparatus main body A, solution injection devices  5  mounted on the arms  3 , rotary drive devices  30  provided at the solution injection device  5 , a lifting/lowering device  20  provided at the disk base  2  for each stage in corresponding relation to each arm  3 , rotating platforms  1  provided at the lifting/lowering devices  20 , and a controller and a piping system which are not shown. In the apparatus main body A, lifting/lowering device driving portions  26  are provided below the disk base  2  and at a first stage for introducing the outer can  100  and a final stage for ejecting the outer can  100 . 
         [0034]    The disk base  2  is fixedly provided on the apparatus main body A and is configured to intermittently rotate by a predetermined angle corresponding to the number of stages by an intermittent rotation drive mechanism such as a barrel cam mechanism. In the first embodiment, the disk base  2  is configured to rotate at intervals of 90° at four stages, but, off course, the disk base  2  is not limited thereto. A plurality of the arms  3  whose number corresponds to the number of stages extend above the disk base  2  and radially from the apparatus main body A. 
         [0035]    The solution injection devices  5  are mounted on the arms  3  and each are configured as follows. An insertion mounting portion  51   a  of a nozzle main body  51  is inserted into a mounting hole  3   a  provided in an end of the arm  3 , and a flange  51   b  of the nozzle main body  51  is bolted to the arm  3 . The nozzle main body  51  has an elongate circular tube shape and is provided with the above flange  51   b  at its upper portion. A mounting ring  51   c  for mounting an inner ring  31   a  of the rotary drive nevice  30  described later is provided directly below the flange  15   b,  a middle portion of the nozzle main body  51  is formed so as to be thin, and a pressure reducing member  52  is mounted on this portion. The portion that is formed so as to be thin is referred to as a small-diameter portion  51   e.  An end portion of the nozzle main body  51  is cut so as to be further thin to be formed as a solution injection nozzle  10 , and the nozzle main body  51  has a nozzle insertion hole  51   d  extending through the center thereof. One or a plurality of first suction holes  51   f  are formed in a lower end surface and a lateral surface of the small-diameter portion  51   c.  It should be noted that a solution inieetion pipe  56  is connected to an upper end portion of the solution injection nozzle  10 . 
         [0036]    The pressure reducing member  52  includes a fixed portion  53 , a rotating portion  55 , and a pressure reducing pad  11 . The fixed portion  53  has a through hole extending through the center thereof, and the aforementioned small-diameter portion  51   e  is inserted therethrough and fixed by a locking screw  54 . A third suction hole  53   a  is formed in an lower surface and a lateral surface of the fixed portion  53 , and a packing  54   a  for blocking a gap between the small-diameter portion  51   e  and the through hole is provided on an inner peripheral surface of the through hole. A pressure reducing pipe  58  is connected to a suction exit of the third suction hole  53   a.    
         [0037]    The rotating portion  55  is a circular tube-shaped member mounted directly below the fixed portion  53 , and is rotatably mounted on a pair of bearings  57  mounted on the small-diameter portion  51   e.  A packing  54   b  for blocking a gap between an upper surface of the rotating portion  55  and the lower surface of the fixed portion  53  is mounted on the upper surface of the rotating portion  55 . Between the upper and tower bearings  57 , there is a gap between an outer peripheral surface of the small-diameter portion  51   e  and an inner peripheral surface of the rotating portion  55 , and this portion serves as a second suction hole  55   a.  The first suction holes  51   f  of the small-diameter portion  51   c  communicate with the second suction hole  55   a.  As a result, the first suction holes  51   f,  the second suction hole  55   a  gaps between inner races and outer races of the bearings  57 , and the third suction hole  53   a  form a suction passage which leads to the pressure reducing pipe  58 . It should be noted that the suction passage is not limited to have suh a shape, and although not shown, the suction passage may extend through the small-diameter portion  51   e.  and communicate directly with the third suction hole  53   a  of the fixed portion  53  and further may extend through the small-diameter portion  51   e  and be open in a lateral surface of the nozzle main body  51  to lead to the pressure reducing pipe  58 . 
         [0038]    The pressure reducing pad  11  is a circular column-shaped member which is hermetically fitted to a lower end portion of the rotating portion  55 , and is formed from an elastomer such as soft rubber or a resin. A suction adhesion portion of the pressure reducing pad  11  has a tapered circular tube shape, and an inner diameter thereof is larger than that of the solution injection hole  101  such that the suction adhesion portion is sized so as to be able to assuredly cover the solution injection hole  101  at the time of adhesion by suction. The suction adhesion portion is not limited to have the shape shown in the drawing and may be a portion with a suction cup shape. Here, reduction of the pressure in the outer can  100  is generally conducted through connection with a vacuum evacuation device, and the degree of evacuation (the degree of vacuum) is preferably equal to or lower than about 10 torr, in order to efficiently conduct injection and filling of the electrolyte L in a suction manner. 
         [0039]    Each rotary drive device  30  includes a driven pulley  33 , a rotation mechanism portion  31 , and a suction adhesion rotator  35 . The rotation mechanism portion  31  includes the inner ring  31   a  which is bolted to the mounting ring  51   e  provided to the nozzle main body  51 ; and an outer ring  31   b  which is rotatably mounted on the inner ring  31   a  via a plurality of steel balls  31   c  arranged at equal intervals. The driven pulley  33  is mounted on the outer ring  31   b.  A rotary driving force is applied to the driven pulley  33  is a timing belt  34  by a drive pulley which is not shown, such that the outer ring  31   b  rotates at a predetermined speed relative to the fixed inner ring  31   a.    
         [0040]    The suction adhesion rotator  35  includes a rotator mounting portion  35   a  which is mounted on the outer ring  31   b;  a guide member  35   b  which includes a flange mounted on a lower surface of the rotator mounting portion  35   a  and has a through hole extending through the center thereof; a slide shaft  35   c  which is slidably inserted through the through hole; a stopper  35   e  which is mounted on an upper end of the slide shaft  35   c;  a suction cohesion block  35   f  which is mounted on a lower end of the slide shaft  35   c;  a spring  35   d  which is provided between the suction adhesion block  35   f  and the guide member  35   b  and presses and urges the suction adhesion block  35   f  downward; and a suction adhesion pad  36  which is mounted on a lower surface of the suction adhesion block  35   f.  The suction adhesion block  35   f  has a suction adhesion hole  35   g  communicating with the suction adhesion pad  36 , and the suction adhesion hole  35   g  is connected to the second suction hole  55   a  of the rotating portion  55  via a suction adhesion pipe  37 . 
         [0041]    Each lifting/lowering device  20  is mounted on the disk base  2  in corresponding relation to each arm  3  as follows. A pair of flange-equipped guide blocks  21  constituting a part of the lifting/lowering device  20  are bolted to a lower surface of the disk base  2 , and lifting/lowering shafts  22  are inserted therethrough so as to be able to freely lift/lower. 
         [0042]    An upper end bar  28  extends on and between upper ends of the lifting/lowering shafts  22 . A rotating shaft  29  is mounted via a bearing on a support portion  28   a  provided on an upper surface of tbe upper end bar  28 , and the rotating platform  1  is fixed to an upper end of the rotating shaft  29 . The rotation center of the rotating shaft  29  coincides with the centerline of the solution injection nozzle  10 . A compression coil spring  28   b  is wound around each lifting/lowering shaft  22  between the upper end bar  28  and the disk base  2  and constantly presses and urges the rotating platform  1  upward. 
         [0043]    The rotating platform  1  is used to place and fix the outer can  100  thereon, and as its fixing means, a clamp system which is not shown, a suction adhesion system in which a void portion  1   a  is provided in the rotating platform  1  and suction adhesion holes  1   b  communicating with the void  1   a  are open in an upper surface of the rotating platform  1  such that a bottom of the outer can  100  is caused to adhere thereto by suction, or another appropriate system is used. Here, the suction adhesion system is used. Placing and fixing the outer can  100  on the rotating platform  1  is conducted such that the position of the solution injection hole  101  of the outer can  100  coincides with the position of the solution injection nozzle  10 . 
         [0044]    A lower end bar  23  extends on and between lower ends of the lifting/lowering shafts  22 . A lifting/lowering drive projection  24  is mounted on a lower surface of the lower end bar  23 , and a lifting/lowering drive groove  25  is provided on a lateral surface of the lifting/lowering drive projection  24  and along the entire circumference thereof. 
         [0045]    The lifting/lowering device driving portions  26  such as cylinders which are not shown are provided below the disk base  2  and at the first stage to which an empty outer can  100  is supplied and the final stage from which an outer can  100  in which the electrolyte L has been filled is ejected, among the stages which are positions at which intermittent rotation of the disk base  2  stops. A lifting/lowering block  27  is mounted on a rod of each lifting/lowering device driving portion  26 , and a pair of lifting/lowering drive hooks  27   a  of the block  27  which have an inverted L shape and whose ends face inside are engageable with and disengageable from the aforementioned lifting/lowering drive groove  25  from left and right. In other words, when the lifting/lowering drive projection  24  moves to the inside of the lifting/lowering, drive hooks  27   a  of the lifting/lowering block  27  as a result of intermittent rotation, a large-diameter portion  24   a  of the lifting/lowering drive projection  24  at the lower side of the lifting/lowering drive groove  25  is fitted therein. Then, the large-diameter portion  24   a  is detached therefrom with intermittent rotation of the disk base  2 . 
         [0046]    Thus, as shown in  FIGS. 1 and 4(A) , the lifting/lowering drive hooks  27   a  of the lifting/lowering device driving portion  26  are engaged with the lifting/lowering drive projection  24  of the rotating platform  1  on the disk base  2  that has stopped at the first stage as a result of intermittent rotation, and the lifting/lowering device driving portion  26  operates to pull the lifting/lowering drive projection  24  downward against elastic forces of the compression coil springs  28   b  to pull the rotating platform  1  downward to a bottom dead point (lowest point). Then, as shown in  FIG. 4(B) , an empty outer can  100  is transferred onto the rotating platform  1  by a transferring means such as a robot hand which is not shown, and is positioned such that the position of the solution injection note  101  of the outer can  100  coincides with the position of the solution injection nozzle  10  as described above. Then, the empty outer can  100  is locked or fixed by suction adhesion on the rotating platform  1 . Subsequently, as shown in  FIG. 4(C) , the lifting/lowering device driving portion  26  operates in a reverse manner to press the lifting/lowering drive projection  24  upward to press the rotating platform  1  upward to a top dead point (highest point). Thus, the solution injection nozzle  10  that has waited directly above the solution infection hole  101  is inserted into the solution injection hole  101 . At the same time, the pressure reducing pad  11  is pressed against a portion surrounding the solution injection hole  101 , and the suction adhesion pad  36  is also pressed against an upper surface of the outer can  100  by the elastic forces of the compression coil springs  28   b.    
         [0047]    When a pressure reducing device which is not shown is activated in this state, air within the outer can  100  is sucked through the pressure reducing pad  11  and the pressure in the outer can  100  is gradually reduced as shown in  FIG. 4(D) . At the same time, air within the suction adhesion pad  36  is also sucked and the suction adhesion pad  36  is caused to adhere to the upper surface of the outer can  100  by suction. Simultaneously with or after this pressure reduction, a solution injection device which is not shown is activated to supply the electrolyte L into the outer can  100 . In addition, when the suction adhesion of the suction adhesion pad  36  is completed, a rotation device such as a motor which is not shown is activated to activate the timing belt  34 . 
         [0048]    By the activation of the timing belt  34 , the suction adhesion pad  36  revolves around the solution injection nozzle  10  at a predetermined speed to rotate the outer can  100  together with the rotating platform  1 . The injected electrolyte L rapidly enters the micro gaps in the electrode assembly  110  within the outer can  100  whose pressure has been reduced, but air bubbles remain within the micro gaps. In addition, gas is occluded in the electrolyte L, and this gas enters the outer can  100  together with the electrolyte L and impedes dense filling of the electrolyte L. Here, since the outer can  100  rotates as described above, the remaining air bubbles and the gas that has entered the outer can  100  together with the electrolyte L are pushed out toward an inner surface of the outer can  100  by the electrolyte L that has rapidly entered the micro gaps in the electrode assenably  110 . Subsequently, the gas and the air bubbles are pushed out to above the electrode assembly  110  along the inner surface by being pushed by the electrolyte L that has spread in the gaps. There is a slight gap between the electrode assembly  110  and a ceiling surface of the outer can  100 , and the pushed-out air and gas are sucked from this gap through the pressure reducing pad  11 . As a result, quick dense filling of the electrolyte L is achieved. 
         [0049]    When the transferring of the outer can  100  onto the rotating platform  1  ends, and the lifting/lowering device driving portion  26  lifts and the insertion of the solution injection nozzle  10  into the outer can  100  and the pressing of the pressure reducing pad  11  and the suction adhesion pad  36  are completed as described above, intermittent rotation of the disk base  2  is enabled, thereby shifting to the next stage. As a result of this movement, the lifting/lowering drive projection  24  is detached from the lifting/lowering drive hooks  27   a  of the lifting/lowering block  27 . The insertion of the solution injection nozzle  10  and the pressing of the outer can  100  against the pressure reducing pad  11  and the suction adhesion pad  36  are kept by the elastic forces of the compression coil springs  28   b.    
         [0050]    Solution injection is conducted simultaneously with or before or after start of the reduction of the pressure in the outer can  100  by the pressure reducing pad  11  (normally, after the start of the pressure reduction). When the pressure reduction is continuously conducted even during the solution injection, it is possible to continuously suck and remove air remaining in the outer can  100  and the gas occluded in the electrolyte L, and thus it is possible to more quickly and densely fill the electrolyte L. In addition, the outer can  100  is rotated after completion of the suction adhesion of the suction adhesion pad  36 . Normally, the outer can  100  is rotated simultaneously with or after the solution injection, but, off course, the outer can  100  may be rotated before the solution injection. 
         [0051]    The solution injection operation is continued until the rotating platform  1  reaches the final stage from the first stage. Since the lifting/lowering device driving portions  26  are provided only at the first stage and the final stage, when the outer can  100  in which the electrolyte L has been filled reaches the final stage, the lifting/lowering drive hooks  27   a  located at the top dead point are engaged with the liffing/lowering drive projection  24 , then the rotating platform  1  is pulled downward to the bottom dead point by the lifting/lowering drive hooks  27   a  through the reverse operation of the lifting/lowering device driving portion  26 , and the outer can  100  in which the electrolyte L has been filled is sent out from the rotating platform  1  as shown in  FIG. 1 . Meanwhile, similarly to the above description, an empty outer can  100  is transferred onto the empty rotating platform  1  that has reached the first stage. 
         [0052]      FIGS. 5 to 7  show a second embodiment of the nozzle main body  51 . The nozzle main body  51  is a double pipe composed of a sheath pipe  51   m  and a nozzle pipe  51   n,  and the nozzle pipe  51   n  is lifted/lowered in a slide hole of the sheath pipe  51  in by a rod of a nozzle insertion/detachment mechanism  40  such as a cylinder which is not shown, via a connection communication pipe  41 . An end portion of the nozzle pipe  51   n  is formed as a thin solution injection nozzle  10  and is extended/retracted from/into a lower end of the slide hole of the sheath pipe  51   m.  In addition, the sheath pipe  51   m  is bolted to the arm  3 , and the solution injection pipe  56  is connected to the connection communication pipe  41 . 
         [0053]    The lifting/lowering of the nozzle pipe  51   n  is conducted at timing in accordance with the pressure reduction operation. In other words, in reducing the pressure in an initial outer can  100  before solution injection, when the solution injection hole  101  of the outer can  100  is blocked by the pressure reducing pad  11  as shown in  FIG. 6 , the nozzle pipe  51   n  is stored within the pressure reducing pad  11 , and the solution injection nozzle  10  is in a state of not being inserted into the solution injection hole  101 . As a result, suction within the outer can  100  through the pressure reducing pad  11  is conducted over the entire area of the solution injection hole  101 , and the suction area is larger than that in a state where the solution injection nozzle  10  is inserted into the solution injection hole  101  as in the first embodiment, by the solution injection nozzle  10 . Thus, the suction rate is increased. When the degree of pressure reduction in the outer can  100  reaches a predetermined value (or when a predetermined time period has elapsed from the start of the pressure reduction), the nozzle pipe  10   b  is projected such that the solution injection nozzle  10  is inserted into the solution injection hole  101 , and then solution injection is started, as shown in  FIG. 7 . The pressure reduction is preferably continuously conducted also during the solution injection. When the solution injection ends, the nozzle pipe  51   n  is retracted toward the sheath pipe  51   m  in side again. 
         [0054]      FIG. 8  shows a third embodiment of the present invention. In this case, the rotating shaft  29  is rotated instead of the suction adhesion pad  36 , and further the solution injection device  5  is lifted/lowered. In this case, the rotating shaft  29  is extended to below the disk base  2 , and the driven pulley  33  is mounted on the extended portion thereof. Thus, when the timing belt  34  is activated, the rotating platform  1  mounted on the rotating shaft  29  also rotates at a predetermined speed. 
         [0055]    Meanwhile, since the solution iniection device  5  lifts/lowers, a main body portion of a nozzle guide  51   g  for guiding the nozzle main body  51  which lifts/lowers is mounted in the mounting hole  3   a  of the arm  3 , and a flange portion of the nozzle guide  51   g  is bolted to a lower surface of the arm  3 . The insertion mounting portion  51   a  which is an upper end portion of the nozzle main body  51  is slidable in a guide hole  51   h  provided in the nozzle guide  51   b.    
         [0056]    The lifting/lowering device  20  on the solution injection device  5  includes, for example, a lifting/lowering cylinder  26   a  which is mounted on the arm  3 , a guide plate  26   c  which is mounted on an outer flange  51   i  provided at a middle portion of the nozzle main body  51 , and a lifting/lowering guide  26   b  which is provided so as to be hanged from the arm  3  and is inserted into a guide hole provided in the guide plate  26   c.  A rod of the above lifting/lowering cylinder  26   a  is mounted on the guide plate  26   c.    
         [0057]    Also in the third embodiment, injection and filling of the electrolyte L is conducted through motion similar to that in the first embodiment, but its mechanism is different therebetween and thus the difference will be mainly described below. Similarly to the first embodiment, an empty outer can  100  is transferred onto the rotating platform  1  on the disk base  2  that has stopped at the first stage as a result of intermittent rotation, for example, by a robot arm. At that time, the lifting/lowering cylinder  26   a  keeps a state where the nozzle main body  51  is pulled upward. When the outer can  100  is fixed at a predetermined position on the rotating platform  1  by suction adhesion or locking, the lifting/lowering cylinder  26   a  operates to lower the nozzle main body  51 : to insert the solution injection nozzle  10  into the solution injection hole  101 ; and to press the pressure reducing pad  11  against the portion surrounding the solution injection hole  101  at the same time. 
         [0058]    After the pressing is completed, when a pressure reducing device which is not shown is activated, air within the outer can  100  is sucked through the pressure reducing pad  11  and the pressure in the outer can  100  is gradually reduced. Simultaneously with or after this pressure reduction, a solution injection device which is not shown is activated to supply the electrolyte L into the outer can  100 . Then, after suction adhesion of the suction adhesion pad  36  is completed, a rotation, device such as a motor which is not shown is activated to activate the timing belt  34 . Thus, since the pressure reducing pad  11  adheres to the outer can  100  by suction, the pressure reducing pad  11  and the rotating portion  55  rotate together with the outer can  100 . Thereafter, similarly to the first embodiment, dense filling of the electrolyte L is conducted by rotation of the outer can  100  about the solution injection nozzle  10 . Then, after or immediately before reaching the final stage, the solution injection is completed. Simultaneously with or after the completion of the solution injection, the reduced pressure is released, and the lifting/lowering cylinder  26   a  finally operates in a reverse manner to pull the nozzle main body  51  upward. Thereafter, the suction adhesion or locking of the rotating platform  1  is released, and the outer can  100  in which the electrolyte L has been filled is sent out from the rotating platform  1 . 
         [0059]    The present invention is not limited to the above-described embodiments, and various modification can be made without departing from the scope of the present invention. 
       DESCRIPTION OF THE REFERENCE CHARACTERS 
       [0000]    
       
           1  rotating platform 
           2  disk base 
           3  arm 
           3   a  mounting hole 
           5  solution injection device 
           10  solution injection nozzle 
           10   c  slide hole 
           11  pressure reducing pad 
           20  lifting/lowering device 
           21  guide block 
           22  lifting/lowering shaft 
           23  lower end bar 
           24  lifting/lowering drive projection 
           24   a  large-diameter portion 
           25  lifting/lowering drive groove 
           26  lifting/lowering device driving portion 
           26   a  lifting/lowering cylinder 
           26   b  lifting/lowering guide 
           26   c  guide plate 
           27  lifting/lowing guide 
           27   a  lifting/lowering drive hook 
           28  upper end bar 
           28   a  support portion 
           28   b  compression coil spring 
           29  rotating shaft 
           30  rotary drive device 
           31  rotation mechanism portion 
           31   a  inner ring 
           31   b  outer ring 
           31   c  steel ball 
           33  driven pulley 
           34  timing belt 
           35  suction adhesion rotator 
           35   a  rotator mounting portion 
           35   b  guide member 
           35   c  slide shaft 
           35   d  spring 
           35   e  stopper 
           35   f  suction adhesion block 
           35   g  suction adhesion hole 
           36  suction adhesion pad 
           37  suction adhesion pipe 
           40  nozzle insertionidetaclunent mechanism 
           41  connection communication pipe 
           51  nozzle main body 
           51   a  insertion mounting portion 
           51   b  flange 
           51   c  mounting ring 
           51   d  nozzle insertion hole 
           51   e  small-diameter portion 
           51   f  first suction hole 
           51   g  nozzle guide 
           51   h  guide hole 
           51   i  outer flange 
           51   m  sheath pipe 
           51   n  nozzle pipe 
           52  pressure reducing member 
           53  fixed portion 
           53   a  third suction hole 
           54  locking screw 
           54   a  packing 
           54   b  packing 
           55  rotating portion 
           55   a  second suction hole 
           56  solution injection pipe 
           57  bearing 
           100  outer can 
           101  electrolyte solution injection hole 
           110  electrode assembly 
         A appatatus main body electrolyte 
         L electrolyte