Patent Publication Number: US-8124269-B2

Title: Secondary battery

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 11/499,728, filed Aug. 7, 2006, now U.S. Pat. No. 7,771,869, which claims priority under 35 U.S.C. 119 to Japanese Patent Application No. 2005-234941 filed Aug. 12, 2005, the entire contents of both of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a secondary battery having an electrode body as a generating element which is accommodated in a pack, from which electric power as generated by the electrode body is taken out through a pair of positive and negative electrode terminals, such as lithium ion secondary batteries and lithium polymer secondary batteries. 
     2. Description of the Related Art 
     In recent years, the demand for portable electronic appliances including information appliances such as notebook personal computers, mobile communication instruments such as mobile telephones, and video cameras is increasing rapidly. Sealed small-sized secondary batteries such as nickel-cadmium batteries, nickel hydrogen batteries, and lithium ion batteries are frequently used as a power source of such an electronic appliance. Above all, lithium ion secondary batteries are employed in various fields while making the most of characteristics such as high voltage, high energy density and lightweight. 
     In particular, as a countermeasure to the liquid leakage which is problematic in the case of using a liquid based electrolytic solution, for example, there is proposed a so-called polymer lithium ion secondary battery using, as an electrolyte, a gel-like polymer film having a polymer impregnated with a non-aqueous electrolytic solution or by using an electrolyte in a fully solid state. 
     Such a polymer lithium ion secondary battery is being further developed for the purpose of meeting the demands for respective electronic appliances in recent years, such as downsizing, lightweight and slimming, while making the most of a characteristic that a degree of freedom of the battery shape is high in addition to the characteristics of a battery such as high energy density and lightweight.
     Patent Document 1: JP-A-2002-8606   

     SUMMARY OF THE INVENTION 
     According to an embodiment of the invention, there is provided a secondary battery which makes the most of advantages of a secondary battery represented by polymer lithium ion secondary batteries and which is able to appropriately meet the demands for electronic appliances in recent years such as downsizing, lightweight and slimming. 
     In order to solve the foregoing problems, according to an embodiment of the invention, there is provided a secondary battery for electronic appliance to be accommodated in an electronic appliance, thereby feeding an electric power to the electronic appliance, the secondary battery being provided with a battery cell in which a positive electrode, a negative electrode and an electrolyte are accommodated in a pack, and a positive electrode terminal and a negative electrode terminal from the positive electrode and the negative electrode, respectively are lead out from the same side face of the pack; a metallic battery can in which one opening from which the battery cell is inserted is formed and which accommodates the battery cell therein such that one side face from which the positive electrode terminal and the negative electrode terminal are lead out is faced towards the opening side; and a lid made of a synthetic resin in which a positive electrode terminal part and a negative electrode terminal part to be connected to the electrodes of the electronic appliance upon being connected to the positive electrode terminal and the negative electrode terminal and being faced outwardly are provided and which plugs the opening of the battery can, the battery cell being accommodated in the battery can while the positive electrode terminal and the negative electrode terminal being curved between the positive electrode terminal and the negative electrode terminal and the lid. 
     In accordance with the secondary battery according to an embodiment of the invention, by configuring the battery main body by using a metallic battery can, it is possible to devise to achieve slimming and to ensure mechanical strengths. Also, since a joining part to the lid on which the positive electrode terminal and the negative electrode terminal and the positive electrode terminal part and the negative electrode terminal part are formed is accommodated in the battery can while being curved, even in the case where an impact is applied between the battery cell and the lid due to falling or vibration of the secondary battery or the like, a load of the impact is absorbed by the curved and accommodated joining part so that it is possible to prevent separation among the positive electrode terminal and the negative electrode terminal and the positive electrode terminal part and the negative electrode terminal part from occurring. 
    
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
         FIG. 1  is an oblique view to show an example of an electronic appliance using a secondary battery to which the invention is applied. 
         FIG. 2  is an oblique view to show a secondary battery to which the invention is applied. 
         FIG. 3  is a detailed oblique view to show a secondary battery to which the invention is applied. 
         FIG. 4  is an oblique view to show a state that a secondary battery to which the invention is applied is installed in a battery accommodating part of an electronic appliance. 
         FIG. 5  is an oblique view to show other example of a secondary battery to which the invention is applied. 
         FIG. 6  is a side view to show a state that a secondary battery to which the invention is applied is installed in a battery installing part which is provided outside an electronic appliance or the like. 
         FIG. 7  is an oblique view of a battery can into which a battery cell is inserted. 
         FIG. 8  is a side view to show a state that an electrode part is provided in an engagement member of a battery installing part which is provided outside an electronic instrument or the like. 
         FIG. 9  is a view to show a secondary battery to which an external label is stuck, in which  FIG. 9A  is a back view,  FIG. 9B  is a plan view, and  FIG. 9C  is a front view. 
         FIG. 10  is a cross-sectional view of a second battery to show a state that a battery lid is assembled. 
         FIG. 11  is a detailed oblique view to show a battery cell. 
         FIG. 12  is a cross-sectional view to show the structure of a pack of a battery cell. 
         FIG. 13  is a side view to show joining between a positive or negative electrode terminal of a battery cell and a positive or negative electrode tab. 
         FIG. 14  is a side view to show a joining part between a positive or negative electrode terminal and a positive or negative tab. 
         FIG. 15  is an oblique view to show a secondary battery in which the arrangement of positive and negative electrode terminal parts is made different depending upon the function. 
         FIG. 16  is an oblique view to show other secondary battery in which the arrangement of positive and negative electrode terminal parts is made different depending upon the function. 
         FIG. 17  is an oblique view to show other example of a secondary battery to which the invention is applied. 
         FIG. 18  is a process chart to show a manufacturing process of a secondary battery to which the invention is applied. 
         FIG. 19  is a side view to show a battery cell, a holder and a substrate as placed in a jig. 
         FIG. 20  is an oblique view to show a battery cell which is inserted into a battery can. 
         FIG. 21  is a cross-sectional view to show a state of a battery cell within a battery can. 
         FIG. 22  is a cross-sectional view to show a state that a battery cell is adhered within a battery can using an adhesive. 
         FIG. 23  is a cross-sectional view to show a state of a battery cell which is adhered within a battery can as adhered by an adhesive. 
         FIG. 24  is an oblique view to show other example of a secondary battery to which the invention is applied. 
         FIG. 25  is an oblique view to show a cell stack. 
         FIG. 26  is an oblique view to show a cell aggregate. 
         FIG. 27  is an oblique view to show a secondary battery to which the invention is applied. 
         FIG. 28  is an oblique view to show a cell aggregate in which an overlap width is folded. 
         FIG. 29  is a front view to show a substrate in which positive and negative electrode terminals as lead out from a cell stack are welded. 
         FIG. 30  is an oblique view to show a battery charger for a secondary battery to which the invention is applied. 
         FIG. 31  is a front view to show a secondary battery which is installed in the foregoing battery charger. 
         FIG. 32  is an oblique view to show other example of a battery charger for a secondary battery to which the invention is applied. 
         FIG. 33  is a cross-sectional view to show the foregoing battery charger in which a secondary battery is installed. 
         FIG. 34  is an oblique view to show the foregoing battery charger in which a holding arm is accommodated. 
         FIG. 35  is an oblique view to show other example of a battery charger for a secondary battery to which the invention is applied. 
         FIG. 36  is an oblique view to show the foregoing battery charger in which a secondary battery is installed. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The secondary battery to which the invention is applied will be hereunder described in detail with reference to the accompanying drawings. A secondary battery  1  to which the invention is applied is, for example, a polymer lithium ion secondary battery and as illustrated in  FIGS. 1A and 1B , is used for various electronic appliances, for example, electronic appliances such as a digital still camera  10 . Concretely, when accommodated in a battery accommodating part  12  as provided inside a grip part  11  of a digital still camera  10  as illustrated in  FIG. 1A , the secondary battery  1  supplies a drive power to this digital still camera  10 . The battery accommodating part  12  is made of a substantially flat concave in response to the shape of the secondary battery  1  and when a battery lid  14  as provided rotatably in a bottom face part  13  of the digital still camera  10  is opened, is faced outwardly. Furthermore, in the battery accommodating part  12 , accommodating part electrodes which are brought into contact with electrode terminal parts  37 ,  38  which are provided in the secondary battery  1  as described later are formed in the bottom part. Further, when the secondary battery  1  is accommodated in the battery accommodating part  12  such that an end face on which the electrode terminal parts  37 ,  38  are provided is an insertion end, the secondary battery  1  is connected to the accommodating part electrodes, thereby supplying a power to the digital still camera  10 . Incidentally, the battery accommodating part  12  is provided with an energizing member (not illustrated) for discharging the secondary battery  1  from the battery accommodating part  12  and an engagement member  19  for engaging the secondary battery  1  within the battery accommodating part  12  in opposition to the energizing member. This engagement member  19  will be described later. 
     The secondary battery  1  will be hereunder described. As illustrated in  FIG. 2  and  FIG. 3 , a battery cell  3  having electrode terminals packed therein is inserted from an opening of a metallic battery can  2  which is formed in a substantially flat form, and the opening of the metallic battery can  2  is plugged by a battery lid  4  provided with terminal parts to which a positive electrode terminal and a negative electrode terminal as lead out from the battery cell  3  are connected, thereby forming this secondary battery  1 . 
     The battery can  2  is made of a metallic casing in which one face of a substantially flat cube is opened and is formed in a substantially trapezoidal shape with respect to the cross section thereof such that an edge in each side of the short sides is formed in a circular arc shape as illustrated in  FIG. 3 . This battery can  2  is formed in a substantially flat cube in which an opening  5  for inserting the battery cell  3  is formed only on one face by molding a metallic material such as iron by deep drawing. By regulating a wall thickness at approximately 0.3 mm, this battery can  2  is formed in a slim shape such that when an accommodating region of the battery cell  3  is eliminated, its own thickness is controlled to the utmost; and at the same time, by using the metallic material, the battery can  2  can be provided with various impact resistances against falling, vibration, and so on, or with mechanical strengths against a sharp knife or the like, thereby preventing deformation, perforation or the like from occurring. The opening  5  is an insertion end from which the battery cell  3  is inserted and after insertion of the battery cell  3 , is plugged by the battery lid  4 . For that reason, plural engagement holes  6  with which engagement convexes  47  as projected on the battery lid  4  are perforated in the periphery of the opening  5 . In the engagement holes  6 , when the battery lid  4  is inserted into the opening  5 , the engagement convexes  47  as projected on the battery lid  4  invade into the opening  5  while being warped and are then engaged with the engagement holes  6 . In this way, the battery lid  4  is assembled in the battery can  2 . 
     When the shape of the battery accommodating part  12  into which the secondary battery  1  is inserted together with the battery can  2  is formed in a substantially trapezoidal shape with respect to the cross section thereof such that an edge in each side of the short sides is formed in a circular arc shape as illustrated in  FIG. 4A , an insertion face of the secondary battery  1  into the battery accommodating part  12  of the digital still camera  10  is defined so that erroneous insertion can be prevented. That is, as illustrated in  FIG. 4A , in the case where the insertion face of the secondary battery  1  is right, the sides of the short sides of the battery accommodating part  12  are coincident with the shape of the principal face of the sides of the short sides of the secondary battery  1  so that the secondary battery  1  can be smoothly inserted. On the other hand, as illustrated in  FIG. 4B , in the case where the insertion face of the secondary battery  1  is reversed, square-shaped edges in the side of the long sides of the secondary battery  1  are interfered by the edges formed in a circular arc shape in the sides of the short sides of the battery accommodating part  12  so that the insertion of the secondary battery  1  can be inhibited. In this way, in the case where the insertion face is reversed in the back and front, not only the insertion of the secondary battery  1  into the battery accommodating part  12  can be prevented, but also a user can easily confirm correctness of the insertion face of the secondary battery  1 . 
     Incidentally, in the case where the secondary battery  1  is externally attached in a battery installing part as formed in the casing of an electronic appliance separately from the battery accommodating part  12  in the bottom face part  7  opposing to the opening  5  or is installed in a battery installing part of a battery charger  80  as illustrated in  FIGS. 5A and 5B , an engagement hole  8  to be engaged with an engagement member  9  as projected in the battery installing part of the electronic appliance or battery charger may be formed in the battery can  2  as illustrated in  FIG. 6 . As illustrate in  FIG. 7 , since a concave  29  is generated on an insertion end face  3   b  of the battery cell  3  as described later, when this engagement hole  8  is formed corresponding to the concave  29 , it is formed without interfering with a battery element  20  which is configured to have a positive electrode, a negative electrode and an electrolyte as accommodated within the battery cell  3 . 
     Incidentally,  FIG. 5A  is a view to show an example in which an engagement hole  8  is formed over the full length in a longitudinal direction of the bottom face part  7 ; and in this case, in the battery can  2 , a first winding part  17  is not provided in an external label  15  as described later, and the bottom face part  7  is exposed externally over the full length. Furthermore,  FIG. 5B  is a view to show an example in which one pair of engagement holes  8 ,  8  are formed in both end parts in a longitudinal direction of the bottom face part  7 ; and in this case, a first winding part  17  for sticking a region exclusive of the both end parts in which the engagement holes  8 ,  8  are formed is provided in the external label  15 . 
     Further, as illustrated in  FIG. 6 , when the secondary battery  1  is engaged with the engagement member  9  which is rotatably energized in an engagement direction of the battery can  2 , the secondary battery  1  can be externally attached in the outside of a casing of an electronic appliance or the like. In this way, in addition to the secondary battery  1  which is accommodated in the battery accommodating part, the separate secondary battery  1  can be easily externally attached in the electronic appliance, whereby the use time of the electronic appliance can be extended. 
     The engagement hole  8  is not limited to the examples as illustrated in  FIGS. 5A and 5B  but can be properly formed in an arbitrary shape. Furthermore, an engagement concave may be provided in the battery installing part, thereby forming an engagement convex provided with a shape corresponding to the engagement concave in the bottom face part  7  of the battery can  2 . 
     Incidentally, with respect to the secondary battery  1  to which the invention is applied, in addition to an embodiment in which a positive electrode terminal part  37  and a negative electrode terminal part  38  are formed and faced outwardly from a terminal hole  48  as formed on a front face  1   c  as described later, there may be employed an embodiment in which not only a positive electrode terminal part  37  is formed in a substrate  35 , but also the engagement hole  8  as formed in the bottom face part of the metallic battery can  2  is used as a negative electrode or an earth electrode. In this case, as illustrated in  FIG. 8A , a can bottom electrode  57  which becomes a negative electrode or an earth electrode is provided in a place for forming the engagement hole  8  in the bottom face part  7  of the battery can  2  and faced outwardly via the engagement hole  8 . In this can bottom electrode  57 , a negative electrode line or an earth line as connected to the substrate  35  is drawn around and connected. Furthermore, in the engagement member  9  which is engaged with this engagement hole  8 , an electrode part  9   a  as connected to an electrode or an earth part in the electronic appliance side is formed and connected to the can bottom electrode  57  at the time of engaging the engagement hole  8  of the secondary battery  1 . 
     Furthermore, in the battery can  2 , after the battery lid  4  is connected, the battery cell  3  is inserted, and the opening  5  is plugged by the battery lid  4 , the insulating external label  15  is stuck. The external label  15  becomes a decorative label of the secondary battery  1  and also devises to achieve insulation of the metallic battery can  2 . As illustrated in  FIG. 3 , the external label  15  is provided with a principal face part  16  for winding the outer periphery of the battery can  2  over the opening  5  and the bottom face part  7 , a first winding part  17  for winding a region exclusive of the both end parts in a longitudinal direction of the bottom face part  7 , and a second winding part  18  for winding a region exclusive of a terminal hole  48  as formed in a top cover  36  of the battery lid  4 . 
     In the external label  15 , since the battery can  2  is formed in a flat shape, a sticking work is easy, and the external label  15  is hardly separated as compared with the case of sticking it directly on the surface of the battery cell  3  as configured to pack the battery element  20 . The first winding part  17  which is wound in the bottom face part  7  of the battery can  2  is formed in a length shorter than that of the bottom face part  7  and stuck to the bottom face part  7  so that both end parts  7   a ,  7   b  in a longitudinal direction of the bottom face part  7  are exposed outwardly. In the battery can  2 , an end part of the bottom face part  7  is formed as an engagement part which is engaged with the engagement member  19  as provided in the battery accommodating part  12  of the digital still camera  10 . That is, as illustrated in  FIGS. 9A and 9B , the secondary battery  1  is formed as an engagement region with which the engagement member  19  in a hook shape for holding the battery can  2  in the battery accommodating part  12  of the digital still camera  10  is engaged. Accordingly, in installing the secondary battery  1 , the engagement member  19  is engaged. In this way, the secondary battery  1  which is always energized towards the outside of the battery accommodating part by an energizing member is engaged with the battery accommodating part  12  in opposition to the energizing force. Furthermore, when the engagement member  19  comes off from the bottom face part  7  of the engagement member  19 , the secondary battery  1  is discharged from the battery accommodating part  12 . 
     Here, where the first winding part  17  of the external label  15  is entirely stuck on the bottom face part  7 , the engagement member  19  rubs the first winding part  17  every time when the secondary battery  1  is inserted into and detached from the battery accommodating part  12 , whereby the external label  15  is gradually rubbed and separated. At this issue, since the external label  15  is wound in a region exclusive of the engagement part which is engaged with the engagement member  19 , the secondary battery  1  is free from rubbing by the engagement member  19  even in the case where it is repeatedly inserted into and detached from the battery accommodating part  12 . 
     Furthermore, in the secondary battery  1 , a region of the bottom face part  7  where the first winding part  17  is stuck is corresponding to a region for forming the electrode terminal parts  37 ,  38  of the battery lid  4 . Accordingly, even in the case where the secondary battery  1  is installed in the battery accommodating part  12  or battery charger  80  while reversing the insertion direction, the insulating external label  15  as stuck to the bottom face part  7  of the battery can  2  comes into contact with the electrode terminal of the accommodating part electrode or the battery charger  80  as provided in the bottom face part of the battery accommodating part  12  corresponding to the electrode terminal parts  37 ,  38 , whereby a danger of short circuit as caused due to the direct contact with the metallic battery can  2  can be prevented. 
     Furthermore, as illustrated in  FIG. 9C , the second winding part  18  of the external label  15  is to enhance an assembling strength between the battery lid  4  and the battery can  2  upon being wound in a region exclusive of the terminal hole  48  as formed on the top cover  36  of the battery lid  4 . When the assembling strength between the battery lid  4  and the battery can  2  is enhanced by the second winding part  18 , as illustrated in  FIG. 10 , by making an engagement depth between the engagement convex  47  as provided on the top cover  36  of the battery lid  4  and the engagement hole  6  which is engaged with the engagement convex  47  as provided in the periphery of the opening  5  of the battery can  2  as described later large and protecting the engagement convex  47  on the upper face of the battery can  2  from the engagement hole  6 , it becomes unnecessary to enhance the assembling strength between the battery can  2  and the battery lid  4 . Accordingly, it is possible to obtain a desired assembling strength without hindering the flatness or appearance of the secondary battery  1 . 
     Incidentally, an information label  49  on which a variety of information of the secondary battery  1  is described is stuck in the principal face part of the side of the long sides of the battery can  2 . 
     Next, the battery cell  3  which is accommodated in the battery can  2  will be described below. As illustrated in  FIGS. 3 and 11 , in the battery cell  3 , a strip positive electrode and a strip negative electrode are stacked via a polymer electrolyte layer and/or a separator; the battery element  20  as wound in a longitudinal direction is packed in a pack  23 ; and a positive electrode terminal  21  and a negative electrode terminal  22  are lead out outwardly from the positive electrode and the negative electrode, respectively. 
     In the positive electrode, a positive electrode active substance layer is formed on a strip positive electrode collector, and a polymer electrolyte layer is further formed on the positive electrode active substance layer. Furthermore, in the negative electrode, a negative electrode active substance layer is formed on a strip negative electrode collector, and a polymer electrolyte layer is further formed on the negative electrode active substance layer. The positive electrode terminal  21  and the negative electrode terminal  22  are welded to the positive electrode collector and the negative electrode collector, respectively. Furthermore, the positive electrode terminal  21  is made of aluminum (Al), and the negative electrode terminal  22  is formed by using nickel (Ni). These positive electrode terminal  21  and negative electrode terminal  22  are connected to a positive electrode tab  31  and a negative electrode tab  32  as held in the battery lid  4  as described later, respectively and coupled with a positive electrode terminal board  33  and a negative electrode terminal board  34  as similarly provided in the battery lid  4  via these positive electrode tab  31  and negative electrode tab  32 , respectively. 
     The positive electrode can be configured by using, as a positive electrode substance, a metal oxide, a metal sulfide or a specific polymer depending upon the kind of the targeted battery. For example, in the case of configuring a lithium ion battery, it is possible to use a lithium composite oxide containing, as the major component, Li x MO 2  (wherein M represents one or more kinds of a transition metal; and x varies depending upon the charge/discharge state of the battery and is usually from 0.05 to 1.10) as the positive electrode active substance. As the transition metal M which configures the lithium composite oxide, Co, Ni, Mn, and so on are preferable. Specific examples of such a lithium composite oxide include LiCoO 2 , LiNiO 2 , LiNi y Co 1-y O 2  (wherein 0&lt;y&lt;1), and LiMn 2 O 4 . Such a lithium composite oxide is able to generate a high voltage and become a positive electrode active substance which is excellent in energy density. Furthermore, lithium-free metal sulfides or oxides such as TiS 2 , MoS 2 , NbSe 2 , and V 2 O 5  can also be used as the positive electrode active substance. A combination of plural kinds of these positive electrode active substances may be used. Furthermore, in forming a positive electrode by using such a positive electrode substance, known conductive agents or binders or the like can be added. 
     A material capable of doping or dedoping lithium can be used as the negative electrode material. For example, sparingly graphitized carbon based materials or carbon materials of a graphite based material can be used. More specifically, there can be used carbon materials such as heat decomposable carbons, cokes (for example, pitch coke, needle coke, and petroleum coke), graphites, vitreous carbons, organic polymer compound calcined bodies (materials resulting from carbonization by calcining a phenol resin, a furan resin, etc. at an appropriate temperature), carbon fibers, and active carbons. Besides, polymers such as polyacetylene and polypyrrole and oxides such as SnO 2  can be used as the material capable of doping or dedoping lithium. In forming a negative electrode from such a material, known binders or the like can be added. 
     The polymer electrolyte is one as prepared by mixing a polymer material, an electrolytic solution and an electrolyte salt and incorporating the gelled electrolyte into the polymer. The polymer material has properties such that it is compatible with the electrolyte solution. Examples thereof include silicon gels, acrylic gels, acrylonitrile gels, poly-phosphazene-modified polymers, polyethylene oxide, and poly-propylene oxide, and composite polymers, crosslinked polymers or modified polymers thereof; and fluorine based polymers such as poly(vinylidene fluoride), poly(vinylidene fluo-ride-co-tetrafluoropropylene), and poly(vinyldiene fluo-ride-co-trifluoroethylene) and mixtures thereof. 
     The electrolytic solution component includes an aprotic solvent which is able to disperse the foregoing polymer material therein, for example, ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC). As the electrolyte salt, one which is compatible with the solvent is used, and a combination of a cation and an anion is used. Examples of the cation which can be used include alkali metals and alkaline earth metals. Examples of the anion which can be used include Cl − , Br − , I − , SCN − , ClO 4   − , BF 4   − , PF 6   − , and CF 3 SO 3   − . Concretely, lithium hexafluorophosphate or lithium tetra-fluorophosphate is used as the electrolytic salt in a concentration such that it can be dissolved in the electrolytic solution. 
     As illustrated in  FIG. 11 , the pack  23  which accommodates the battery element  20  therein is formed by cutting a cell aggregate  27  having a substantially rectangular accommodating sheet  24  in which plural accommodating concaves  25  for accommodating the battery element  20  therein are arranged in advance and a sealing sheet  26  as welded on the accommodating sheet  24  in which the battery element  20  is accommodated and capable of sealing each of the accommodating concaves  25  for every battery element  20 . 
     The accommodating sheet  24  is formed in a longitudinal shape such that the plural accommodating concaves  25  are arranged via an overlap width  28  with a prescribed width. The accommodating concaves  25  are formed in a substantially rectangular shape depending upon the shape of the battery element  20 . Furthermore, the arrangement direction of the accommodating concaves  25  is not limited to the direction of the short side as illustrated in  FIG. 11 , but the accommodating concaves  25  may be arranged in a direction of the long side or may be arranged lengthwise and crosswise. The overlap width  28  spacing the respective accommodating concaves  25  is a joining face of the sealing sheet  26  for sealing the accommodating concaves  25 . Further, when the battery element  20  is accommodated in each of the accommodating concaves  25  as illustrated by an arrow A in  FIG. 11 , the sealing sheet  26  is heat welded on the overlap width  28 , thereby forming the cell aggregate  27  (refer to  FIG. 26 ) having the battery elements  20  integrated therein. 
     Incidentally, at this time, the positive electrode terminal and the negative electrode terminal as extended from the positive electrode and the negative electrode are lead out in the same direction from the joining part with sealing sheet  26 . Furthermore, at this time, evacuation is carried out simultaneously with the welding by using a vacuum pump (not illustrated). Due to this suction force, the battery element  20  is sealed in the accommodating concave  25  covered by the accommodating sheet  24  and the sealing sheet  26 . Moreover, by sucking the inside of the accommodating concave  25 , the pack  23  for accommodating the battery element  20  therein is drawn and squeezed and is formed in a substantially trapezoidal shape with respect to the cross section thereof such that an edge in each side of the short sides is formed in a circular arc shape, in which a second face side which is the bottom face side of the accommodating concave  25  is small, whereas a first face side which is the opening side is large, depending upon the shape of the battery element  20 . 
     Furthermore, in the battery cell  3 , a clearance is provided between the battery element  20  and the accommodating sheet  24  in such a manner that the battery element  20  is not pressed against the side face of the accommodating concave  25 . Further, when the accommodating sheet  24  and the sealing sheet  26  are sealed while being drawn ad squeezed, the concave  29  is formed on the face in the side opposite to the battery cell  3  from which the positive electrode terminal  21  and the negative electrode  22  are lead out (see  FIG. 7 ). Moreover, after sealing the accommodating sheet  24  and the sealing sheet  26 , in each of the battery cells  3 , the principal face in the side of the sealing sheet  26  is formed in a flat shape by pressing. Thereafter, the cell aggregate  27  is cut along the overlap width  28  and separated every pack  23  having the battery element  20  sealed therein, thereby forming the battery cells  3 . 
     Incidentally, in addition to the formation of the battery cell  3  by forming the cell aggregate  27  and cutting it along the overlap width  28 , the battery cell  3  may be formed by accommodating the battery element  20  in a previously cut accommodating sheet for every individual battery cell and joining with a sealing sheet which is similarly cut for every individual battery cell. 
     Each of the accommodating sheet  24  and the sealing sheet  26  which configure the pack  23  has a stack structure in which a polypropylene (PP) layer  52 , an aluminum (Al) layer  53 , and a nylon layer  54  are stacked in this order from the inside as illustrated in  FIG. 12 . Here, the aluminum layer  53  is used for the purpose of preventing the invasion of moisture into the pack  23  and preventing the expansion of the battery element  20 . Furthermore, the polypropylene layer  52  not only prevents the denaturation of the polymer electrolyte but also becomes a joining face between the accommodating sheet  24  and the sealing sheet  26 . That is, joining of the accommodating sheet  24  and the sealing sheet  26  is carried out by opposing the polypropylene layers  52  to each other and heat melting them at about 170° C. 
     Incidentally, the configuration of the pack  23  is not limited thereto, but laminate films having various materials and stack structures and the like can be employed. Furthermore, the joining method is not limited to the heat melting. Examples of the configuring material of the pack  23  include aluminum, polyethylene terephthalate (PET), non-axially stretched polypropylene (CPP), acid-modified polypropylene, ionomers, and ON. 
     The battery lid  4  having a terminal part to be connected to the positive electrode terminal  21  and the negative electrode terminal  22  which are lead out from the same side face of the battery cell  3  and plugging the opening  5  of the battery can  2  is configured to have a holder  30  for inserting and holding the positive electrode tab  31  and the negative electrode tab  32  which are connected to the positive electrode terminal  21  and the negative electrode terminal  22 , respectively, the substrate  35  provided with the positive electrode terminal board  33  and the negative electrode terminal board  34  which are connected to the positive electrode tab  31  and the negative electrode tab  32 , respectively, and the top cover  36  which sandwiches the holder  30  together with the substrate  35  and which is engaged with the opening  5  of the battery can  2  and is manufactured by integrally assembling the folder  30 , the substrate  35  and the top cover  36  as illustrated in  FIG. 3 . 
     The holder  30  is a component as formed in a substantially trapezoidal flat plate shape such that an edge in each side of the short sides is formed in a circular arc shape, which is prepared by mold forming a synthetic resin in substantially the same shape as the opening  5  of the battery can  2 . In this holder  30 , one pair of insertion holes  41 ,  42  through which the positive electrode tab  31  and the negative electrode tab  32  are inserted, respectively are formed in the vicinity of the side faces of the sides of the short sides, and by inserting and holding the positive electrode tab  31  and the negative electrode tab  32  in the insertion holes  41 ,  42 , respectively, it is devised to position the positive electrode tab  31  and the negative electrode tab  32  and also to prevent falling of the secondary battery  1  or position deviation as caused following the vibration or the like. Accordingly, the positive tab  31  and the negative electrode tab  32  are able to prevent a situation that welding between the positive electrode terminal  21  and the negative electrode terminal  22  comes out due to falling or position deviation as caused following the vibration or the like. 
     The positive electrode tab  31  and the negative electrode tab  32  are provided for the purpose of connecting the positive electrode terminal  21  and the negative electrode terminal  22  which are lead out from the battery cell  3  to the positive electrode terminal board  33  and the negative electrode terminal board  34  as provided in the substrate  35  which becomes an electrode terminal of the secondary battery  1 , and when inserted and supported in the holder  30 , one ends  31   a ,  32   a  are extended to the side of the battery cell  3 , whereas the other ends  31   b ,  32   b  are extended and held in the side of the substrate  35 . In these positive electrode tab  31  and negative electrode tab  32 , by using nickel (Ni), the one ends  31   a ,  32   a  are disposed on the positive electrode terminal  21  and the negative electrode terminal  22 , respectively, the other ends  31   b ,  32   b  are disposed on the positive electrode terminal board  33  and the negative electrode terminal board  34  as provided on the substrate  35 , respectively, and four points are then welded collectively by spot welding. This is because since the positive electrode terminal  21  is formed by using aluminum (Al), if the positive electrode terminal  21  is welded directly to the positive electrode terminal board  33 , the aluminum is molten so that the connection cannot be achieved. Accordingly, by mediating the positive electrode tab  31  and the negative electrode tab  32  and carrying out welding from the upper side, the positive electrode terminal  21  is connected to the positive electrode terminal board  33 , and the negative electrode terminal  22  is connected to the negative electrode terminal board  34 . 
     Furthermore, as illustrate in  FIGS. 13A and 13B , in the respective one ends  31   a ,  32   a  of the positive electrode tab  31  and the negative electrode tab  32 , folding parts  39 ,  40  in which tip edges thereof are folded towards the face in the opposite side to the contact face coming into contact with the positive electrode terminal  21  and the negative electrode terminal  22  are formed. In the folding parts  39 ,  40 , as illustrated in  FIG. 14 , the positive electrode tab  31  and the negative electrode tab  32  each has a thickness of 0.1 mm, whereas the tip thereof is folded in a height of about 0.3 mm. In this way, by folding the tip side, the positive electrode tab  31  and the negative electrode tab  32  are each made to stand up in a circular arc shape having gaps G and joined with the positive electrode terminal  21  and the negative electrode terminal  22 , respectively as described later. Thereafter, when a joining part  50  is folded, even in the case where the tip comes into contact with the positive electrode terminal  21  or the negative electrode terminal  22 , it is possible to prevent the generation of a situation that the positive electrode terminal  21  or the negative electrode terminal  22  is damaged or cut. 
     Incidentally, a ground  43  for discharging an electric charge as charged on the battery can  2  is connected to the negative electrode tab  32 . When the ground  43  is supported by the holder  30 , one end thereof can be connected to the negative electrode tab  32 , whereas the other end can be brought into contact with the inner surface of the battery can  2 . In this way, even in the case where an electric charge is charged on the metallic battery can  2 , the electric charge can be discharged into the negative electrode tab  32  through the ground  43  so that there is no possibility for causing an erroneous operation of a microcomputer within the secondary battery  1  or an electronic appliance having the secondary battery  1  installed therein due to the electric charge as charged on the battery can  2 . Incidentally, the earth may be connected to the substrate  35 , thereby discharging an electric charge into the negative electrode tab  32  through the substrate  35 . 
     Furthermore, on upper and lower faces  30   a ,  30   b  of the holder  30 , plural coupling projections  44  which are inserted and engaged in coupling holes  46  as provided on the top cover  36  are intermittently formed over the longitudinal direction. When the coupling projections  44  are engaged in the coupling holes  46 , the holder  30  is coupling with the top cover  36 , thereby sandwiching the substrate  35 . 
     The substrate  35  is a rigid substrate on which a circuit pattern for supplying an electric current flowing from the battery cell  3  into an electronic appliance via the terminal boards  33 ,  34  is formed and mounted with the positive electrode terminal board  33  and the negative electrode terminal board  34  which are welded to the other ends  31   b ,  32   b  of the positive electrode tab  31  and the negative electrode tab  32 , respectively. The positive electrode terminal board  33  and the negative electrode terminal board  34  are connected to the positive electrode terminal part  37  and the negative electrode terminal part  38 , respectively as formed on the face in the opposite side to the mounting face. Further, in the substrate  35 , the positive electrode terminal part  37  and the negative electrode terminal part  38  are faced outwardly via the terminal holes  48  as provided on the top cover  36  and brought into contact with the electrode terminals as provided in the side of the digital still camera  10  or the battery charger  80  (refer to  FIG. 30 ). 
     The positive electrode terminal part  37  and the negative electrode terminal part  38  are formed in a different arrangement from each other depending upon the function of the secondary battery  1 . The reasons for this are as follows. In the secondary battery  1  which is used in various electronic appliances, there is some case where nevertheless the external shape is identical with respect to the battery can  2  or the battery lid  4 , by making the battery capacity different depending upon an electronic appliance to be used, or by making a compatible electronic appliance different, plural types of the secondary batteries  1  which are incompatible with each other are provided. Furthermore, there is some case where there are provided a plural number of the secondary batteries  1  having a different function from each other such as a combination of a type provided with a residual battery life display part such as an LED display part or a liquid crystal display part and a residual battery life display button, thereby bringing a residual battery life display function and a type not having such a residual battery life display function; and a combination of a type which is able to achieve quick recharge and a type which is not able to achieve quick recharge. 
     However, since the external shape of the secondary battery  1  is identical in all types having any function, there is some possibility that the secondary battery  1  is installed in an incompatible electronic appliance. Then, by making the arrangement of the positive electrode terminal part  37  and the negative electrode terminal part  38  different for every function and similarly making the arrangement of electrode terminals of a compatible electronic appliance different, it becomes possible to prevent any trouble as caused due to erroneous installation of the secondary battery. 
     Concretely, the positive electrode terminal part  37  and the negative electrode terminal part  38  are arranged in a position of substantial point symmetry for every function. For example, in a secondary battery  1 A having a battery capacity of 760 mAh as illustrated in  FIG. 15A  and a secondary battery  1 B having a high battery capacity of 830 mAh as illustrated in  FIG. 15B , the positive electrode terminal part  37  and the negative electrode terminal part  38  are arranged in a position of substantial point symmetry as rotated through 180 degrees. Incidentally, the positive electrode terminal part  37  and the negative electrode terminal part  38  may be arranged in a position of bilateral symmetry for every function as illustrated in  FIGS. 16A and 16B . Furthermore, the arrangement shape of substantial point symmetry can be properly selected. 
     In this way, by making the arrangement of the positive electrode terminal part  37  and the negative electrode terminal part  38  different depending upon the function of the secondary battery  1  and making the arrangement of electrode terminals of an electronic appliance corresponding to the function different, even in the case where the secondary battery  1  is installed in an incompatible electronic appliance, since the electrode terminals in the electronic appliance side do not come into contact with the electrode terminals in the side of the secondary battery  1 , it is possible to prevent any trouble as caused due to erroneous installation of the incompatible secondary battery  1 . 
     In the substrate  35 , a circuit pattern and a land are formed by etching with a copper foil as stuck on an insulating substrate or the like, and the positive electrode terminal board  33  and the negative electrode terminal board  34  are mounted on the land by reflow soldering. As described previously, the positive electrode terminal board  33  and the negative electrode terminal board  34  are soldered on the positive tab  31  and the negative tab  32  together with the positive electrode terminal  21  and the negative electrode terminal  22 , respectively. Furthermore, the positive electrode terminal part  37  and the negative electrode terminal part  38  are formed on the land as formed in a prescribed place by gilding or the like. 
     Incidentally, if desired, the substrate  35  may be provided with a heat-sensitive element such as PTC (positive temperature coefficient) for detecting the temperature of the secondary battery  1  to achieve charge control or safety control. By providing a heat-sensitive element, when the temperature is elevated, the secondary battery  1  is able to shut and control an input/output circuit. 
     The top cover  36  which sandwiches the substrate  35  together with the holder  30  is a component in a substantially trapezoidal flat plate shape such that an edge in each side of the short sides is formed in a circular arc shape, which is prepared by mold forming a synthetic resin in substantially the same shape as the opening  5  of the battery can  2  and can be engaged with the opening  5  closely. In the top cover  36 , on an upper face  36   a  in the side of the short side and a lower face (not shown) in the side of the long side, plural coupling holes  46  in which plural coupling projections  44  as projected on the holder  30  are inserted and engaged are intermittently formed corresponding to the coupling projections  44 . Furthermore, in the top cover  36 , the plural engagement convexes  47  which are engaged with the engagement holes  6  as formed in the periphery of the opening  5  of the battery can  2  are formed on the upper face  36   a  and the lower face (not shown). Further, when the top cover  36  is inserted into the battery can  2  from the opening  5  in such a manner that the upper face  36   a  and the lower face  36   b  are slightly warped, the engagement convexes  47  are engaged with the engagement holes  6  and assembled in the battery can  2 . 
     Furthermore, in the top cover  36 , the terminal holes  48  from which the positive electrode terminal part  37  and the negative electrode terminal part  38  as formed in the substrate  35  are faced outwardly are perforated on the front face  36   c , and the positive electrode terminal part  37  and the negative electrode terminal part  38  are brought into contact with the electrode terminals in the side of an electronic appliance such as the digital still camera  10  or the battery charger  80  via the terminal holes  48 . Incidentally, the terminal hole  48  is, for example, provided in three places depending upon the terminal part as formed in the substrate  35  and can be made to work for a positive electrode terminal, a negative electrode terminal and for a terminal for information such as residual battery life, respectively. Incidentally, the number of the terminal holes  48  can be properly increased or decreased depending upon the terminal part as provided in the substrate  35 . 
     When the positive electrode terminal  21  and the negative electrode terminal  22  of the battery cell  3  are connected to the positive electrode terminal board  33  and the negative electrode terminal board  34  of the substrate  35  via the positive electrode tab  31  and the negative electrode tab  32  as held in the holder  30 , respectively and the coupling projections  44  of the holder  30  are then inserted into the coupling holes  46 , the top cover  36  is coupled with the holder  30  while sandwiching the substrate  35  therebetween, thereby forming the battery lid  4 . Thereafter, when the engagement convexes  47  of the top cover  36  are engaged with the engagement holes  6  as formed in the periphery of the opening  5  of the battery can  2 , the battery lid  4  is assembled in the battery can  2 , thereby forming the secondary battery  1 . 
     Incidentally, in the top cover  36 , as illustrated in FIGS.  17 A,  17 B and  17 C, in the case where it is externally attached in a battery installing part as formed in the casing of an electronic appliance separately from the battery accommodating part  12  on the front face  36   c  or in the case where it is installed in a battery installing part of the battery charger  80 , engagement parts  79  which are engaged with engagement projections  78  as projected in the battery installing part of the electronic appliance or the battery charger may be formed. In the secondary battery  1 , as illustrated in  FIG. 6 , the battery can  2  is installed while engaging the engagement parts  79  with the engagement projections  78 . The engagement parts  79  can be easily formed in mold forming the top cover  36 . Incidentally,  FIG. 17A  shows an example in which the engagement parts  79  are formed in a concave form in the both ends of the front face  36   c  of the top cover  36 ;  FIG. 17B  shows an example in which the both ends of the engagement parts  79  in a concave form are notched; and  FIG. 17C  shows an example in which engagement concaves are provided in the battery installing part, and convex engagement parts  79  provided with a shape corresponding to the engagement convexes are formed in the top cover  36  of the secondary battery  1 . 
     Incidentally, in this specification, with respect to the secondary battery, the principal face in the side of the short side of the battery can  2  is referred to as the upper face  1   a  of the secondary battery  1 ; the principal face on the side of the long side of the battery can  2  is referred to as the lower face  1   b  of the secondary battery  1 ; the front face  36   c  of the top cover  36  is referred to as the front face  1   c  of the secondary battery  1 ; and the bottom face part  7  of the battery can  2  is referred to as the back face  1   d  of the secondary battery  1 . 
     Next, the manufacturing process of the secondary battery  1  will be described below with reference to  FIGS. 18A to 18L . First of all, as illustrated in  FIG. 18A , the battery cell  3  and the substrate  35  are arranged in a jig, the details of which are omitted. Incidentally, at this time, the battery cell  3  is cut along the overlap width  28  of the cell aggregate  27  and folded along the side face of the battery cell  3  into a substantially trapezoidal shape with respect to the cross section thereof, thereby making it easy for handling; and as described later, in accommodating in the battery can  2 , when the folded overlap width  28  is arranged between the side face of the battery can  2  and the battery cell  3 , it functions as a buffer member. Furthermore, in the substrate  35 , a prescribed circuit pattern and the positive electrode terminal part  37  and the negative electrode terminal part  38  are formed, and the positive electrode terminal board  33  and the negative electrode terminal board  34  are reflow soldered. 
     Incidentally, with respect to the formation of the battery cell  3 , in addition to the case of forming the cell aggregate  27  and cutting it along the overlap width  28 , a sealing sheet may be joined with an accommodating sheet having the battery element  20  accommodated therein for every individual battery cell. 
     The battery cell  3  is arranged in such a manner that the joining face between the accommodating sheet  24  from which the positive electrode terminal  21  and the negative electrode terminal  22  are lead out and that the sealing sheet  26  are faced upwardly and that the bottom part of the accommodating concave  25  is faced downwardly. That is, the battery cell  3  in a substantially trapezoidal form with respect to the cross section thereof is arranged in such a manner that the side of the short side is faced downwardly and that the side of the long side from which the positive electrode terminal  21  and the negative electrode terminal  22  are lead out is faced upwardly. Furthermore, the battery cell  3  is arranged in such a manner that the lead-out face  3   a  from which the positive electrode terminal  21  and the negative electrode terminal  22  are lead out is faced towards the side of the substrate  35 . The substrate  35  is arranged in such a manner that the mounting face on which the positive electrode terminal board  33  and the negative electrode terminal board  34  are mounted is faced upwardly and that the side of the short side in a substantially trapezoidal shape is faced towards the side of the lead-out face  3   a  of the battery cell  3 . 
     Next, as illustrated in  FIG. 18B , in the holder  30 , the positive electrode tab  31  and the negative electrode tab  32  are inserted in and held by the insertion holes  41 ,  42 . Furthermore, at this time, the ground  43  is also installed in the holder  30 . Next, as illustrated in  FIG. 18C , by installing this holder  30  in a jig, the holder  30  is arranged between the battery cell  3  and the substrate  35 . In the holder  30 , the side of the short side in a substantially trapezoidal shape in which the positive electrode tab  31  and the negative electrode tab  32  are held is faced downwardly and positioned with the short side of the substrate  35 . Furthermore, in the holder  30 , the one end  31   a  of the positive electrode tab  31  is superposed on the positive electrode terminal  21  of the battery cell  3 , and the one end  32   a  of the negative electrode tab  32  is superposed on the negative electrode terminal  22 . Moreover, the other end  31   b  of the positive electrode tab  31  is superposed on the positive electrode terminal board  33  of the substrate  35 , and the other end  32   b  of the negative electrode tab  32  is superposed on the negative electrode terminal board  34 . In this way, the positive electrode terminal  21  and the negative electrode terminal  22  of the battery cell  3 , the positive electrode tab  31  and the negative electrode tab  32  of the holder  30 , and the positive electrode terminal board  33  and the negative electrode terminal board  34  of the substrate  35  are placed on substantially the same plane (see  FIG. 19 ). 
     Next, four places of the one end  31   a  and the other end  31   b  of the positive electrode tab  31  and the one end  32   a  and the other end  32   b  of the negative electrode tab  32  are welded from the upper side, respectively, thereby joining the positive electrode terminal  21  of the battery cell  3  to the one end  31   a  of the positive electrode tab  31 , the negative electrode terminal  22  to the one end  32   a  of the negative tab  32 , the positive electrode terminal board  33  of the substrate  35  to the other end  31   b  of the positive electrode tab  31 , and the negative electrode terminal board  34  to the other end  32   b  of the negative electrode tab  32 , respectively. Here, though aluminum (Al) is used for the positive electrode terminal  21 , since the positive electrode terminal  21  is welded from the upper side of the positive electrode tab  31  made of nickel, the both can be surely joined to each other without the generation of dissolution by heat. 
     Next, as illustrated in  FIG. 18D , the substrate  35  is made to stand up, thereby superposing the holder  30  thereon. At this time, in the respective other ends  31   b ,  32   b  of the positive electrode tab  31  and the negative electrode tab  32  which are held by the holder  30 , the base end parts which are projected from the insertion holes  41 ,  42  in the side of the substrate  35  are folded along the standing-up direction of the substrate  35 . 
     Next, as illustrated in  FIG. 18E , insulating paper  51  is stuck so as to cover the joining part  50  among the positive electrode terminal  21  and the negative electrode terminal  22  and the one end  31   a  of the positive electrode tab  31  and the one end  32   a  of the negative electrode tab  32 . The insulating paper  51  not only reinforces the joining part  50  among the positive and negative electrode terminals  21 ,  22  and the positive and negative electrode tabs  31 ,  32  but also prevents the generation of a short circuit due to the contact between the metallic battery can  2  and the joining part  50  and the generation of a short circuit between the positive electrode and the negative electrode due to deformation of the positive electrode tab  31  and the negative electrode tab  32 . In the insulating paper  51 , an adhesive layer is formed in the side of one face, and by folding the insulating paper  51  while sandwiching the joining part  50  as illustrated in  FIG. 18F , the adhesive layers are stuck to each other, thereby achieving sticking. 
     Next, as illustrated in  FIG. 18G , the holder  30  is coupled with the top cover  36 , thereby forming the battery lid  4 . Thereafter, as illustrated in  FIG. 18H  and  FIGS. 13A and 13B , the joining part  50  among the positive electrode terminal  21  and the negative electrode terminal  22  and the one end  31   a  of the positive electrode tab  31  and the one end  32   a  of the negative electrode tab  32  is folded in a substantially S-shaped form such that the lead-out face  3   a  of the battery cell  3  and the battery lid  4  are faced at each other. In this way, by accommodating the joining part  50  in a curved state in the battery can  2 , even in the case where an impact is applied between the battery cell  3  and the battery lid  4  by falling, vibration, or the like, a load of the impact is absorbed by the joining part  50  as folded in a substantially S-shaped from and accommodated so that it is possible to prevent separation or breakage of the positive electrode terminal  21  and the negative electrode terminal  22  and the positive electrode tab  31  and the negative electrode tab  32  from occurring (see  FIGS. 13A and 13B ). 
     Next, as illustrated in  FIG. 18I , in the battery cell  3 , an elastic member  55  having a slight thickness and having an adhesive layer formed on the both sides thereof is stuck on the insertion end face  3   b  into the battery can  2 . This elastic member  55  not only makes the battery cell  3  fix inside the battery can  2 , thereby preventing unsteadiness but also absorbs an impact which is applied to the battery cell  3 . Examples of the elastic member  55  include a pressure sensitive adhesive double coated tape using a polyurethane foam as a base material. The insertion end face  3   b  of the battery cell  3  is not formed in a flat shape and is a face in which the shape thereof is liable to be scattered. However, the scattering is absorbed by the elastic member  55  so that the battery cell  3  can be surely adhered to the inside of the battery can  2 . Furthermore, the elastic member  55  can absorb an impact which is applied to the battery cell  3  due to falling, vibration, or the like or can reduce a load to the joining part  50  due to heat expansion of the battery cell  3 . Thus, the elastic member  55  is able to prevent separation of the positive electrode terminal  21  and the negative electrode terminal  22  and the positive electrode tab  31  and the negative electrode tab  32  from occurring together with the foregoing insulating paper  51 . 
     When the elastic member  55  is formed in a substantially rectangular shape depending upon the shape of the insertion end face  3   b  of the battery cell  3  and arranged in the both end parts in a longitudinal direction along the side face of the battery cell  3 , an insulating film  56  for insulating the overlap width  28  of the battery cell  3  from the battery can  2  is stuck. That is, the accommodating sheet  24  and the sealing sheet  26  which configure the pack  23  of the battery cell  3  are each a sheet in which the polypropylene (PP) layer  52 , the aluminum (Al) layer  53 , and the nylon layer  54  are stacked in this order from the inside as described previously. When cut along the overlap width  28 , the respective layers which configure the sheet are exposed outwardly on the cut face. Among them, when the aluminum layer  53  comes into direct contact with the metallic battery can  2 , in the case where the battery can  2  is charged, the aluminum layer  53  becomes a genitive electrode. When the polypropylene layer  52  further has a hole due to some cause, the aluminum layer  53  has a hole by electrolytic corrosion. Further, there is some possibility that when moisture invades from the hole of the pack  23 , the battery cell  3  is expanded. Then, by arranging the insulating film  56  along the cut face of the battery cell  3 , it is devised to achieve insulation between the battery can  2  and the cut face of the pack  23 , thereby preventing the expansion of the battery cell  3  due to moisture absorption of the battery element  20 . 
     The insulating film  56  is a longitudinal film as formed depending upon the side face of the battery cell  3 , one end of which is stuck to each of the end parts of the elastic member  55 . As illustrated in  FIG. 20 , when the battery cell  3  is inserted into the battery can  2  from the insertion end face  3   b , the insulating film  56  is folded along the side face of the battery cell  3  by a side edge part of the opening  5  of the battery can  2  and arranged between the cut face of the overlap width  28  as folded on the side face of the battery cell  3  and the side face of the battery can  2 . In this way, it is possible to prevent the contact between the aluminum layer  53  as exposed on the cut face of the overlap width  28  and the battery can  2 . 
     Next, as illustrated in  FIG. 18J , the battery cell  3  is inserted into the battery can  2 , and the opening  5  of the battery can  2  is plugged by the battery lid  4 . At this time, the battery cell  3  is inserted in such a manner that the side of the short side and the side of the long side of the substantially trapezoidal shape with respect to the cross section thereof are made adaptive with the side of the short side and the side of the long side of the battery can  2  as formed similarly substantially trapezoidal shape with respect to the cross section thereof. In this way, a space within the battery can  2  can be effectively utilized so that a prescribed clearance is provided between the battery can  2  and the battery cell  3 . As illustrated in  FIGS. 21A to 21C , this clearance becomes a margin in the case where the battery cell  3  is expanded by heat or the like so that an excessive load to the joining part  50  or deformation of the battery can  2  as caused due to the expansion of the battery cell  3  can be avoided. Incidentally,  FIG. 21A  shows the case where the both principal faces of the battery cell  3  are equally expanded; and each of  FIGS. 21B and 21C  schematically shows the case where the both principal faces of the battery cell  3  are unequally expanded. 
     Furthermore, in the case where the direction of the battery cell  3  is reversed, since the edge of each side of the long sides of the battery cell  3  interferes with the edge in a circular arc shape as formed in each side of the short sides of the battery can  2 , thereby preventing the invasion, it is possible to prevent erroneous insertion from occurring. 
     As illustrated in  FIG. 20 , when the battery cell  3  is inserted, the insulating film  56  is arranged along the side face of the battery cell  3  by the side edge of the opening  5  of the battery can  2 . Furthermore, the battery cell  3  is adhered to the bottom face part of the battery can  2  by the elastic member  55  as stuck on the insertion end face  3   b . Subsequent to the insertion of the battery cell  3 , the engagement convexes  47  as projected on the top cover  36  invade into the opening  5  while being warped and are then engaged with the engagement holes  6 . In this way, the battery lid  4  is assembled in the opening  5  of the battery can  2 . 
     Furthermore, when the battery lid  4  is assembled in the battery can  2 , the joining part  50  among the positive electrode terminal  21  and the negative electrode terminal  22  and the positive electrode tab  31  and the negative electrode tab  32  is arranged in a curved state in a substantially S-shaped form between the battery cell  3  and the holder  30 . 
     Next, as illustrated in  FIG. 18K , the external label  15  is stuck to the periphery of the battery can  2 . The external label  15  is stuck such that the principal face part  16  winds the outer periphery of the battery can  2 ; that the first winding part  17  winds a region exclusive of the both end parts in the longitudinal direction of the bottom face part  7 ; and that the second winding part  18  winds a region exclusive of the terminal hole  48  as formed in the top cover  36  of the battery lid  4 . Finally, as illustrated in  FIG. 18L , the information label  49  on which a variety of information of the secondary battery  1  is described is stuck in the principal face part of the side of the long sides of the battery can  2  to which the external label  15  has been stuck, thereby completing the second battery  1 . 
     According to the secondary battery  1  having the foregoing configuration, by mutually assembling the metallic battery can  2  and the mold formed battery lid  4 , assembling can be easily achieved. Furthermore, by forming the battery can  2  by deep drawing using a metallic material, slimming and insurance of strength can be achieved at the same time so that it is possible to provide a secondary battery which is able to meet the demands for an electronic appliance such as downsizing, slimming and lightweight. In addition, the external shape of the engagement hole  8  or the engagement part  79  which becomes the installing end in installing the secondary battery in a battery installing part of an electronic appliance can be easily formed by processing the metallic battery can  2  or mold forming the battery lid  4  made of a synthetic resin. 
     Furthermore, in the secondary battery  1 , when the battery can  2  and the battery lid  4  are formed in a substantial trapezoidal shape with respect to the cross section thereof in which the edge of each side of the short sides is formed in a circular arc shape and the battery accommodating part  12  in the side of the digital still camera  10  is formed in the same shape, in the case where the insertion face is reversed in the back and front, the edges of the battery accommodating part  12  and the edges of the secondary battery  1  interfere with each other, thereby inhibiting the insertion. Thus, it is possible to surely prevent erroneous insertion. 
     Furthermore, in the battery can  2 , it is possible to provide the can bottom electrode  57  in the bottom face part  7  to which the external label  15  is not stuck, thereby using it as a negative electrode or an earth electrode. Moreover, when the both ends of the bottom face part  7  to which the external label  15  is not stuck are an engagement part with which the engagement member  19  as provided in the side of an electronic appliance is engaged, even when rubbed repeatedly by the engagement member  19 , a situation such as breakage or separation of the external label  15  can be prevented from occurring. Moreover, by forming a sticking region of the external label  15  which is stuck in the bottom face part  7  of the battery can  2  into a region corresponding to a position of each of the positive electrode terminal part  37  and the negative electrode terminal part  38  of the secondary battery  1 , even when the secondary battery  1  is installed in an erroneous direction of an electronic appliance such as the digital still camera  10  or the battery charger  80 , since the insulating external label as stuck in the bottom face part  7  of the secondary battery  1  comes into contact with the side of the digital still camera  10  or the battery charger  80  as provided corresponding to the position of each of the positive electrode terminal part  37  and the negative electrode terminal part  38 , it is possible to prevent a short circuit due to direct contact of the bottom face part  7  from occurring. In addition, by winding the external label  15  in a region exclusive of a forming region of each of the positive electrode terminal part  37  and the negative electrode terminal part  38  of the battery lid  4 , it is possible to enhance the assembling strength between the battery can  2  and the battery lid  4 . Accordingly, since it is not required to protrude the engagement convexes  47  as formed on the battery lid  4  which is engaged with the battery can  2  in the upper face side of the battery can  2  from the engagement hole  6 , the assembling strength can be ensured without hindering the flatness or appearance of the second battery  1 . 
     In addition, in the secondary battery  1 , by making the position of each of the positive electrode terminal part  37  and the negative electrode terminal part  38  which are formed on the battery lid  4  different depending upon a difference in the function such as battery capacity while making the battery can  2  and the battery lid  4  have the same shape, even in the case where the secondary battery  1  of an incompatible type is installed in the incompatible digital still camera  10 , conductance does not occur between the electrode terminals so that a trouble can be prevented from occurring. 
     In addition, in the secondary battery  1 , when the battery can  2  and the battery cell  3  are formed in a substantial trapezoidal shape with respect to the cross section thereof in which the edge line of each side of the short sides is formed in a circular arc shape, it is possible to prevent erroneous insertion of the battery cell  3  into the battery can  2  and to effectively utilize a space within the battery can  2 . In this way, it is possible to provide a clearance which when the battery cell  3  is heat expanded, becomes a margin between the battery cell  3  and an inner wall of the battery can  2 . Accordingly, even in the case where the battery cell  3  is heat expanded, the battery can  2  does not cause distortion, or an excessive load is not applied to the joining part  50  among the positive electrode terminal  21  and the negative electrode terminal  22  and the positive electrode tab  31  and the negative electrode tab  32 . 
     In addition, in the secondary battery  1 , the battery lid  4  is configured to have the holder  30  for devising to position and fix the positive electrode tab  31  and the negative electrode tab  32 , the substrate  35  provided with the positive electrode terminal part  37  and the negative electrode terminal part  38 , and the top cover  36  for sandwiching the substrate  35  together with the holder  30 . In this way, in the holder  30 , by devising to position the positive electrode tab  31  and the negative electrode tab  32  and holding them, it is positive to easily achieve welding with the positive electrode terminal  21  and the negative electrode terminal  22  or with the positive electrode terminal board  33  and the negative electrode germinal board  34 . Also, even in the case where an impact is applied by falling or vibration of the secondary battery  1 , or the like, it is possible to prevent a situation that the welded portion between the positive electrode tab  31  and the negative electrode tab  32  comes out. 
     In addition, in the secondary battery  1 , since the battery can  2  is installed on the insertion end face  3   b  of the battery cell  3  via the elastic member  55 , not only unsteadiness of the battery cell  3  within the battery can  2  can be prevented, but also an impact due to falling or vibration of the battery can  2 , or the like can be absorbed, thereby preventing the impact to apply to the joining part  50 . Furthermore, by folding the overlap width  28  along the side face and then inserting the battery cell  3  into the battery can  2 , it is possible to make the folded overlap width function as a buffer member between the battery cell  3  and the battery can  2 . 
     In addition, in the secondary battery  1 , by sticking the insulating film  56  on the elastic member  55 , when the battery cell  3  is inserted into the battery can  2 , the insulating film  56  is arranged along the side face of the battery cell  3  while being guided on the side face of the opening  5  of the battery can  2  to cover the aluminum layer  53  of the pack  23  which is exposed on the cut face of the overlap width  28 , thereby enabling it to devise to insulate from the inner wall of the battery can  2 . Accordingly, even in the case where the metallic battery can  2  is charged, it is possible to prevent a phenomenon in which the battery can  2  is directly contact with the aluminum layer  53  of the pack  23  to become the negative electrode, and the polypropylene layer  52  has a hole due to some cause, thereby causing electrolytic corrosion, the pack  23  has a hole, and moisture invades from this hole, thereby causing expansion of the battery cell  3 . 
     In addition, in the secondary battery  1 , since the insulating paper  51  is stuck to the joining part  50  among the positive electrode terminal  21  and the negative electrode terminal  22  and the positive electrode tab  31  and the negative electrode tab  32 , not only it is possible to reinforce the joining part  50 , but also it is possible to prevent the generation of a short circuit as caused due to the contact with the metallic battery can  2 . Furthermore, by accommodating this joining part  50  into the battery can  2  while being curved in a substantially S-shaped form, even in the case where an impact is applied between the battery cell  3  and the battery lid  4  due to falling or vibration of the secondary battery  1  or the like, the joining part  50  which has been folded in a substantially S-shaped form and accommodated is warped so that a load of the impact is absorbed, thereby preventing the separation of the positive electrode terminal  21  and the negative electrode terminal  22  and the positive electrode tab  31  and the negative electrode tab  32  from occurring. 
     Incidentally, as described previously, in the secondary battery  1  to which the invention is applied, the battery cell  3  is adhered to the inside of the battery can  2  via the elastic member  55 . However, as illustrated in  FIGS. 22A to 22C , there may be employed a configuration in which prior to the insertion of the battery cell  3 , an adhesive  58  is coated on one principal face within the battery can  2 , and the adhesive  58  is spread on the one principal face within the battery can  2  by the battery cell  3  to be inserted into the battery can  2 , thereby adhering the battery cell  3  to the battery can  2 . By employing such a configuration, the battery cell  3  can be fixed in the battery can  2 , thereby preventing unsteadiness of the battery cell  3  within the battery can  2  as caused by falling or vibration of the secondary battery  1  or the like. Accordingly, an excessive load is not applied to the joining part  50  among the positive electrode terminal  21  and the negative electrode terminal  22  and the positive electrode tab  31  and the negative electrode tab  32  so that it is possible to prevent the separation of the positive electrode terminal  21  and the negative electrode terminal  22  and the positive electrode tab  31  and the negative electrode tab  32 . 
     Furthermore, by fixing the battery cell  3  inside the battery can  2  by using the adhesive  58 , it is possible to effectively utilize a space within the battery can  2 , and it is possible to form a prescribed clearance between the principal face of the battery cell  3  in the opposite side to the adhesive face and an inner wall of the battery can  2  opposing to the foregoing principal face. Accordingly, as illustrated in  FIG. 23 , even in the case where the battery cell  3  is heat expanded, since a margin against the volume exposition of the battery cell  3  is ensured by the clearance, it is possible to prevent a situation that distortion is generated in the battery can  2  or that an excessive load is applied to the joining part  50 . 
     Furthermore, in the secondary battery to which the invention is applied, there may be employed not only a configuration in which the single battery cell  3  is inserted into the battery can  2  but also a configuration as illustrated in  FIG. 24 , in which a cell stack  61  having plural battery cells  3  stacked therein is formed and inserted into a single battery can  62 . A secondary battery  60  which is configured to accommodate the cell stack  61  therein will be described below. Incidentally, with respect to the same members as in the foregoing secondary battery  1 , the same symbols are given, and details thereof are omitted. 
     In the cell stack  61 , plural battery cells  3  are stacked in such a manner that lead-out faces  3   a  from which a positive electrode terminal  21  and a negative electrode terminal  22  are lead out are faced towards the same direction, and if desired, the respective battery cells  3  may be adhered to each other. In the cell stack  61 , the positive electrode terminal  21  and the negative electrode terminal  22  as lead out from each of the battery cells  3  are welded with a positive electrode terminal board  66  and a negative electrode terminal board  67  of a substrate  65  which configures a battery lid  64 , respectively. 
     In the cell stack  61 , by folding the foregoing cell aggregate  27  along an overlap width  28 , the battery cells  3  are stacked. The battery cell  3  may be stacked in two stages as illustrated in  FIG. 24  or may be stacked in three stages as illustrate in  FIG. 25 . In the case where the battery cell  3  is stacked in three stages, as illustrate in  FIG. 26 , the cell aggregate  27  is formed such that widths W 1  and W 2  of the overlap widths  28  to be provided between the respective battery cells  3  are made different. In the secondary battery  60 , the battery capacity and the voltage can be freely set up by the stacking number of the battery cell  3  and the wiring among the respective battery cells  3 . 
     Incidentally, the cell stack  61  may be formed by individually cutting out the battery cell  3  from the cell aggregate  27  and stacking the battery cells such that the lead-out faces  3   a  are faced towards the same direction. 
     In the substrate  65 , a positive electrode terminal board  66  and a negative electrode terminal board  67  with which a positive electrode terminal  21  and a negative electrode terminal  22  as lead out from each of the battery cells  3  are welded, and a positive electrode terminal part  71  and a negative electrode terminal part  72  which are connected to the positive electrode terminal board  66  and the negative electrode terminal board  67 , respectively by a circuit pattern and which are faced outwardly via a terminal hole  70  as formed on a top cover  69  are formed. 
     In the secondary battery  60 , the stacked battery cells  3  can be set up by a circuit pattern of the substrate  65  such that they are connected in series or in parallel. Such a circuit pattern is formed by an etching process with a copper foil, a printing process with a conductive paste, or the like. Furthermore, the positive electrode terminal board  66  and the negative electrode terminal board  67  are mounted on the land by reflow soldering. The positive electrode terminal part  71  and the negative electrode terminal part  72  are formed on the land as formed in a prescribed place by gilding or the like. Incidentally, likewise the foregoing secondary battery  1 , the positive electrode terminal part  71  and the negative electrode terminal part  72  may be arranged in a different position depending upon a difference in every function such as battery capacity of the secondary battery  60 . The substrate  65  is sandwiched by a holder  68  and the top cover  69  and configures a battery lid  64  together with the holder  68  and the top cover  69 . 
     The holder  68  is coupled with the top cover  69  via the substrate  65 , thereby sandwiching the substrate  65  together with the top cover  69 . In this way, the holder  68  receives a pressing pressure which is applied to the positive electrode terminal part  71  and the negative electrode terminal part  72  together with the top cover  69 , thereby preventing a situation that an excessive load is applied to the positive electrode terminal part  71  and the negative electrode terminal part  72 . This holder  68  is prepared by mold forming a synthetic resin in substantially the same shape as an opening  63  of the battery can  62 . Furthermore, in the holder  68 , on an upper face  68   a  and a lower face (not shown), plural coupling projections  73  which are engaged in coupling holes  74  as formed on the top cover  69  are intermittently formed. 
     The top cover  69  which holds the substrate  65  together with the holder  68  is a component which is prepared by mold forming a synthetic resin in substantially the same shape as the opening  63  of the battery can  62  and can be engaged with the opening  63  closely. In the top cover  69 , on an upper face  69   a  and a lower face (not shown), plural coupling holes  74  in which the plural coupling projections  73  as projected on the holder  68  are inserted and engaged are intermittently formed corresponding to the coupling projections  73 . Furthermore, in the top cover  69 , on the upper face  69   a  and lower face (not shown) plural engagement convexes  77  with which engagement holes  76  as formed in the periphery of the opening  63  of the battery can  62  are engaged are formed. Further, when the top cover  69  is inserted into the battery can  62  from the opening  63  while the upper face  69   a  and lower face (not shown) are slightly warped, the engagement convexes  77  are engaged with the engagement holes  76  and assembled in the battery can  62 . 
     Furthermore, in the top cover  69 , terminal holes  70  are projected on a front face  69   c  such that the positive electrode terminal part  71  and the negative electrode terminal part  72  as formed on the substrate  65  are faced outwardly, and the positive electrode terminal part  71  and the negative electrode terminal part  72  are brought into contact with an electrode terminal in the side of an electronic appliance such as the digital still camera  10  or the battery charge  80  through the terminal holes  70 . 
     In the top cover  69 , after connecting the positive electrode terminal  21  and the negative electrode terminal  22  of the battery cell  3  to the positive electrode terminal board  66  and the negative electrode terminal board  67  of the substrate  65 , respectively, by inserting the coupling projections  73  of the holder  68  into the coupling holes  74 , the tope cover  69  is coupled with the holder  68  while sandwiching the substrate  65 , thereby forming the battery lid  64 . Thereafter, when the engagement convexes  77  of the top cover  69  are engaged with the engagement holes  76  as formed in the periphery of the opening  63  of the battery can  62 , the battery lid  64  is assembled in the battery can  62 , thereby forming the secondary battery  60 . 
     The battery can  62  into which the cell stack  61  is inserted is made of a metallic casing in which one face of a substantially flat cube is opened and is formed in a substantially rectangular shape with respect to the cross section thereof depending upon the shape of the cell stack  61 . In the battery scan  62 , the opening  63  for inserting the cell stack  61  is formed only on one face by molding a metallic material such as iron by deep drawing. By regulating a wall thickness at approximately 0.3 mm, this battery can  62  is formed in a slim shape such that when an accommodating region of the battery cell  3  is eliminated, its own thickness is controlled to the utmost; and at the same time, by using the metallic material, the battery can  62  can be provided with mechanical strengths against various impacts such as falling, and vibration. The opening  63  is an insertion end from which the cell stack  61  is inserted and after insertion of the cell stack  61 , is plugged by the battery lid  64 . For that reason, plural engagement holes  76  with which engagement convexes  77  as projected on the battery lid  64  are perforated in the periphery of the opening  63 . In the engagement holes  76 , when the battery lid  64  is inserted into the opening  63 , the engagement convexes  77  as projected on the battery lid  64  invade into the opening  63  while being warped and are then engaged with the engagement holes  76 . In this way, the battery lid  64  is assembled in the battery can  62 . 
     Incidentally, likewise the foregoing secondary battery  1 , in the battery can  62 , in the case where it is externally attached in a battery installing part of an electronic appliance in the bottom face part opposing to the opening  63  or in the case where it is installed in the battery installing part of the battery charger  80 , engagement holes which are engaged with engagement convexes as projected in the battery installing part may be formed. Furthermore, engagement concaves may be provided in the battery installing part, and engagement convexes may be formed in the bottom face part of the battery can  62 . Similarly, likewise the foregoing secondary battery  1 , in the top cover  69 , in the case where it is externally attached in a battery installing part of an electronic appliance in a prescribed place of a front face  69   c  or in the case where it is installed in the battery installing part of the battery charger  80 , concave engagement parts which are engaged with engagement convexes as protected in the battery installing part may be formed. Furthermore, engagement concaves may be provided in the battery installing part, and convex engagement parts may be formed in the front face  69   c  of the top cover  69 . 
     Incidentally, in the battery can  62 , likewise the foregoing secondary battery  1 , after connecting it to the battery lid  64 , inserting the cell stack  61  and plugging the opening  63  by the battery lid  64 , an insulating external label  15  and an information label  49  in which a variety of information of the secondary battery  60  is described are stuck. The configuration and effect of the external label  15  are the same as in the case where it is stuck to the foregoing secondary battery  1 . 
     Furthermore, the battery can  62  may be formed in a substantially trapezoidal shape with respect to the cross section thereof in which the edge line in the direction of short sides is formed in a circular arc shape as illustrate in  FIG. 27 , in addition to the case where the battery can  62  is formed in a substantially rectangular shape with respect to the cross section thereof. By taking such a shape, the secondary battery  60  can be prevented from erroneous insertion into the battery installing part of an electronic appliance such as the digital still camera  10  or the battery charger  80 . 
     The foregoing secondary battery  60  is manufactured as follows. First of all, as illustrated in  FIG. 28 , the cell aggregate  27  is cut in such a manner that two or more of battery cells  3  are continued depending upon the stacking number of the battery cell  3  and folded along the overlap width  28  so as to stack the battery cells  3 , thereby forming the cell stack  61 . 
     Next, as illustrated in  FIG. 29 , the positive electrode terminal  21  and the negative electrode terminal  22  which are lead out from each of the battery cells  3  of the cell stack  61  are welded with the positive electrode terminal board  66  and the negative electrode terminal board  67  as mounted on the substrate  65 . Incidentally, in the substrate  65 , the circuit pattern for connecting the respective battery cells  3  in series or in parallel and the positive electrode terminal part  71  and the negative electrode terminal part  72  are formed in advance in a separate process, and the positive electrode terminal beard  71  and the negative electrode terminal board  72  are mounted; and the substrate  65  is supported by the holder  68 . 
     Next, the holder  68  and the top cover  69  are coupled with each other to form the battery lid  64 , and the cell stack  61  is subsequently inserted into the opening  63  of the battery can  62 . At this time, in the cell stack  61 , by sticking the elastic member  55  having the insulating film provided therein to the insertion end face  3   b  of each of the battery cells  3 , the pack  23  may devise to achieve insulation from the inner wall of the battery can  62  by the insulating film  56  at the same time of inserting the battery can  62  or may be fixed to the battery can  62  by the elastic member  55 . 
     Subsequent to the insertion of the cell stack  61 , the battery lid  64  is assembled in the opening  63  of the battery can  62 . Thereafter, the external label  15  is stuck to the battery can  62 . As described previously, the external label  15  becomes a decorative label of the secondary battery  60  and also devises to achieve insulation of the metallic battery can  62 . Furthermore, the external label  15  is provided with the principal face part  16  for winding the outer periphery of the battery can  62 , the first winding part  17  for winding a region exclusive of the both end parts in a longitudinal direction of the bottom face part of the battery can  62 , and the second winding part  18  for winding a region exclusive of the terminal hole  70  as formed in the top cover  69  of the battery lid  64 . 
     In this way, in the secondary battery  60 , the both ends in the bottom face part of the battery can  62  become an engagement part with which the engagement member as provided in the battery accommodating part of an electronic appliance. Also, when the external label  15  is stuck so as to wind even the battery lid  64 , it is possible to ensure an assembling strength between the battery lid  64  and the battery can  62  without hindering the flatness and appearance. 
     According to the thus configured secondary battery  60 , by using the cell stack  61  having plural battery cells  3  stacked therein as the need arises, it is possible to easily obtain a secondary battery with high battery capacity or a secondary battery with long life. Furthermore, in the secondary battery  60 , since the respective battery cells  3  can be connected in series or in parallel depending upon the circuit pattern as formed on the substrate, it is possible to devise to achieve high capacity or long life with ease. 
     Next, the battery charger  80  for charging the foregoing secondary battery will be described below. The battery charger  80  is used as a battery charger which is common in plural kinds of secondary batteries  1  which are equal in the outer shape but are different in a point that the positive electrode terminal part  37  and the negative electrode terminal part  38  which are faced from the front face  1   c  are arranged in a position of substantial point symmetry depending upon a difference in a battery capacity or a compatible electronic appliance, the presence or absence of a residual battery life display function, or a difference between a type which is able to achieve quick recharge and a type which is not able to achieve quick recharge. 
     As illustrated in  FIG. 30 , the battery charger  80  has a battery charge main body  81 , a battery accommodating part in which the secondary battery  1  is accommodated, an electrode terminal  83  which is arranged within the battery accommodating part  82  and which is brought into contact with the positive electrode terminal part  37  and the negative electrode terminal part  38  of the secondary battery  1 , and a transparent part  84  in which the electrode terminal  83  can be viewed from the outside of the battery charger main body  81 . 
     As illustrated in  FIG. 30 , the battery charger main body  81  is, for example, made of a cube larger than the secondary battery  1 , and the battery accommodating part  82  is formed in a principal face part  81   a . The battery accommodating part  82  is a concave having substantially the same size as the secondary battery  1 ; and the electrode terminal  83  is formed in one side wall part  82   a  corresponding to the position of the positive electrode terminal part  37  and the negative electrode terminal part  38  which are faced outwardly from the terminal holes  48  as provided in the front face  1   c  of the secondary battery  1 . Furthermore, in the battery charger main body  81 , the transparent part  84  capable of enhancing the visibility of the electrode terminal  83  is formed from a side wall part  82   a  in which the electrode terminal  83  is formed to the principal face part  81   a . By providing the transparent part  84 , a user of the battery charger  80  can easily view the position of the electrode terminal  83  from the upper side. Furthermore, in installing the secondary battery  1  in the battery accommodating part  82 , it is possible to easily confirm that the positive electrode terminal part  37  and the negative electrode terminal part  38  in the side of the secondary battery  1  are connected to the electrode terminal  83  in the side of the battery charger main body  81  without making a mistake on the insertion direction. Besides, the battery charger main body  81  is provided with a cord for taking in an external power source, a display part for displaying the charging state by an LED element or a liquid crystal, and so on, details of which are, however, omitted. 
     Here, as described previously, the secondary battery  1  which is installed in the battery charger  80  is formed in such a manner that the arrangement of the positive electrode terminal part  37  and the negative electrode terminal part  38  is made different depending upon the function, for example, whether or not it is of a high battery capacity type, whether or not a residual battery life display function by LED, a liquid crystal, or the like is provided, a difference of a compatible electronic appliance, or whether or not quick recharge is possible. That is, while the outer shape of the battery can  2  and the battery lid  4  which configure the secondary battery  1  is the same regardless of a difference of the function, the positive electrode terminal part  37  and the negative electrode terminal part  38  which are formed in the substrate  35 , which configure the battery lid  4 , are arranged in a position of substantial point symmetry depending upon the foregoing every function. Similarly, the electrode terminal which is provided in the side of an electronic appliance takes an arrangement corresponding to the arrangement of the positive electrode terminal part  37  and the negative electrode terminal  38  of the corresponding secondary battery. In this way, even in the case where the secondary battery  1  is installed in an incompatible electronic appliance, since the positive electrode terminal part  37  and the negative electrode terminal part  38  in the side of the secondary battery  1  do not come into contact with the electrode terminal as provided in the side of the electronic appliance, it is possible to prevent a trouble as caused due to erroneous installation. Incidentally, at this time, since the electrode terminal in the side of the electronic appliance comes into contact with the front face  36   c  of the top cover  36  made of a synthetic resin, it is prevented from the occurrence of direct contact with the metallic battery can  2 . 
     On the other hand, what plural battery chargers are prepared for every function even at the time of charging the secondary battery  1  requires a user to use a battery charger for each purpose and is complicated. Furthermore, this also requires a product supplier to manufacture and manage plural kinds of battery chargers so that it is complicated. 
     Then, in the present battery charger  80 , with respect to plural secondary batteries  1  having a different position of the positive electrode terminal part  37  and the negative electrode terminal part  38  for every function, change of the installation direction makes it possible to achieve common use. Concretely, in the secondary battery  1 , since the positive electrode terminal part  37  and the negative electrode terminal part  38  are arranged in a position of substantial point symmetry for every function, as illustrate in  FIG. 31 , when a secondary battery  1 B in which the positive electrode terminal part  37  and the negative electrode terminal part  38  are arranged in a position of substantial point symmetry is rotated through 180 degrees against a secondary battery  1 A, the positive electrode terminal part  37  and the negative electrode terminal part  38  of the both become the same positions. Accordingly, in the case where the secondary battery  1 A is installed in the battery charge  80 , an upper face  1   a  in the side of the short side is positioned upwardly; and in the case where the secondary battery  1 B is installed in the battery charger  80 , it is rotated through 180 degrees such that a lower face  1   b  is positioned downwardly. In this way, in all of the secondary batteries  1 A,  1 B, charging can be carried out by bringing the positive electrode terminal part  37  and the negative electrode terminal part  38  into contact with the electrode terminal  83  as formed in the side of the battery charger  80 . 
     Incidentally, it is possible to easily confirm whether or not each of the positive electrode terminal part  37  and the negative electrode terminal part  38  comes into contact with the electrode terminal  83  of the battery charger main body  81  through the transparent part  84  regardless of the installation direction regarding the secondary batteries  1 A,  1 B. Also, the correctness of the installation direction regarding the secondary batteries  1 A,  1 B can be confirmed by a display part for displaying the charging state or the like. 
     Here, in the case where the secondary battery  1 A is installed in such a manner that the lower face  1   b  is faced upwardly and the secondary battery  1 B is installed in such a manner that the upper face  1   a  is faced upwardly, since each of the positive electrode terminal part  37  and the negative electrode terminal part  38  does not come into contact with the electrode terminal  83 , charging is not achieved. At this time, since the electrode terminal  83  comes into contact with the front face  36   c  of the top cover  36  made of a synthetic resin, it is prevented from the occurrence of direct contact with the metallic battery can  2 . Furthermore, even in the case where the secondary batteries  1 A,  1 B are installed in such a manner that the front face  1   a  and the back face  1   d  are reversed, since the electrode terminal  83  comes into contact with the back face  1   d  of the secondary battery  1 , charging is not achieved. At this time, since the electrode terminal  83  is brought into contact with the first winding part  17  of the external label  15  as stuck on the bottom face of the battery can  2 , it is prevented from the occurrence of direct contact with the metallic battery can  2 . 
     Furthermore, such a compatible battery charger may be configured as follows. As illustrated in  FIG. 32 , a battery charger  90  is provided with a battery charger main body  91  in a substantially rectangular shape, a holding arm  92  which is slidably supported by side faces  91   a ,  91   b  of the battery charger main body  91  opposing to each other and which supports the secondary battery  1 , and an electrode terminal  93  as provided on a front face  91   c  of the battery charger main body  91 . In this battery charger  90 , the secondary battery  1 A or  1 B in which the positive electrode terminal part  37  and the negative electrode terminal part  38  are arranged in a position of substantial point symmetry is installed from one direction or the other direction of the holding arm  92  which holds the secondary battery  1 . 
     The holding arm  92  is provided with one pair of arm parts  95 ,  95  which are slidably supported by the both side faces  91   a ,  91   b  of the battery charger main body  91  and a holding part  96  which is provided over one pair of the arm parts  95 ,  95  in tip parts of the arm parts  95 ,  95  and which holds the secondary battery  1 A or  1 B. 
     The arm parts  95 ,  95  are a longitudinal member and when slidably supported by the both side faces  91   a ,  91   b  of the battery charger main body  91  at an interval substantially equal to the width of the secondary battery  1 , is drawn out into the side of the front face  91   c  of the battery charger main body  91 . The holding part  96  which is formed in the tip parts of the arm parts  95 ,  95  is a member in a substantially T-shaped form which supports the battery can  2  of the secondary battery  1  and has a supporting wall  97  which configures a front face of the battery charger main body  91  and which supports the bottom face part of the battery can  2  and a placing face part  98  which projects from substantially the center in the height direction of the supporting wall  97  towards the side of the front face  91   c  of the battery charger main body  91  over the arm parts  95 ,  95  and in which the both faces thereof are placing faces  98   a ,  98   b  on which a rear end part of the battery can  2  is placed. 
     When the arm parts  95 ,  95  are slid in the side of the back face  91   d  of the battery charger main body  91 , the supporting wall  97  becomes a front face of the battery charger main body  91 . Furthermore, when the arm parts  95 ,  95  are slid in the side of the front face  91   c  of the battery charger main body  91  and the secondary battery  1  is installed in the supporting arm  92 , the supporting wall  97  supports the bottom face part  7  of the battery can  2 . 
     In the placing face part  98 , in the direction from the supporting wall  97  to the side of the front face  91   c  of the battery charger main body  91 , the placing faces  98   a ,  98   b  are each an inclination face as inclined towards the center in the thickness direction of the front face  91   c . Further, in installing the secondary battery  1  in the holding arm  92 , the rear end part of the battery can  2  is placed, and the placing face part  98  is inclined in such a manner that the front face  36   c  of the top cover  36  from which the positive electrode terminal part  37  and the negative electrode terminal part  38  are faced is able to come into contact with the electrode terminal  93  as formed on the front face  91   c  of the battery charger main body  91 . That is, when the rear end part of the battery can  2  is placed on the both placing faces  98   a ,  98   b  of the placing face part  98 , the positive electrode terminal part  37  and the negative electrode terminal part  38  are brought into contact with the electrode terminal  93  of the battery charger main body  91 . 
     The holding arm  92  holds the secondary battery  1  by one pair of the arm parts  95 ,  95 , the placing face  98   a  or placing face  98   b , and the supporting wall  97 . At this time, as illustrated in  FIGS. 33A and 33B , the holding arm  92  holds the secondary battery  1 A in which the positive electrode terminal part  37  and the negative electrode terminal part  38  are arranged in a position of substantial point symmetry each on the placing face  98   a  and the secondary battery  1 B on the placing face  98   b , respectively depending upon the function. At this time, each of the secondary batteries  1 A,  1 B is installed in the holding arm  92  in such a manner that each lower face  1   b  is an insertion face. Furthermore, the secondary battery  1 A which is held on the placing face  98   a  and the secondary battery  1 B which is held on the placing face  98   b  are installed while being rotated through 180 degrees each other. In this way, in all of the secondary batteries  1 A,  1 B, since the positive electrode terminal part  37  and the negative electrode terminal part  38  are turned to the same position, they come into contact with the electrode terminal  93  as formed in the side of the front face  91   c  of the battery charger main body  91 , whereby charging can be achieved. 
     Incidentally, in the case where the secondary batteries  1 A,  1 B are installed from the side of the upper face  1   a  while reversing the insertion face, in the case where the secondary battery  1 A is installed in the side of the placing face  98   b , or in the case where the secondary battery  1 B is installed in the side of the placing face  98   a , since the positive electrode terminal part  37  and the negative electrode terminal part  38  do not come into contact with the electrode terminal  93  as formed on the front face  91   c  of the battery charge main body  91 , charging is not achieved. At this time, since the electrode terminal  93  comes into contact with the front  36   c  of the top cover  36  made of a synthetic resin, it is prevented from the occurrence of direct contact with the metallic battery can  2 . Also, in the case where the secondary batteries  1 A,  1 B are installed while reversing the upper faces  1   a  and the back faces  1   d , they are not charged because the electrode terminal  93  comes in contact with the back faces  1   d  of the secondary batteries  1 A and  1 B. In this case, the electrode terminal  93  is prevented from coming in direct contact with the battery can  2  made of a metal because the electrode terminal  93  comes in contact with the first winding part  17  of the external label  15  stuck on the bottom face of the battery can  2 . 
     Furthermore, as illustrated in  FIG. 34 , since at the time of non-use, the arm parts  95 ,  95  can be slid in the side of the back face  91   d  of the battery charger main body  91 , the battery charger  90  is excellent in portable properties and is able to prevent the breakage of the arm parts  95 ,  95  or the like. 
     Furthermore, such a compatible battery charger may be configured as follows. As illustrated in  FIG. 35 , a battery charger  100  is provided with a battery charger main body  101  in a substantially rectangular shape, a battery installing part  102  as provided on an upper face  101   a  of the battery charger main body  101 , an electrode terminal  103  which is formed within the battery installing part  102  and which comes into contact with the positive electrode terminal part  37  and the negative electrode terminal part  38 , and one pair of battery holders  104 A,  104 B which are rotatably provided on the upper face  101   a  of the battery charger main body  101  and which hold the secondary batteries  1 A,  1 B. In this battery charger  100 , by installing in the battery holder  104 A or  104 B by altering the direction of the secondary battery  1  depending upon the arrangement of the positive electrode terminal part  37  and the negative electrode terminal part  38 , thereby enabling the electrode terminal  103  of the battery installing part  102  to come into contact with the positive electrode terminal part  37  and the negative electrode terminal part  38 , not only compatibility of plural kinds of secondary batteries  1 A,  1 B is ensured, but also in the case where the direction is improper, insertion in the battery holder  104 A or  104 B is inhibited. Thus, erroneous installation of the secondary batteries  1 A,  1 B is prevented. 
     The battery charge main body  101  is formed in a substantially rectangular box-like shape, and the battery installing part  102  in which the secondary battery  1  is installed from the side of the front face  1   c  is formed in substantially the center of the upper face  101   a . Furthermore, in the battery charger main body  101 , one pair of the battery holders  104 A,  104 B are provided rotatably towards the upper direction on the upper face  101   a.    
     The battery installing part  102  is a concave in which the secondary battery  1  is installed from the side of the front face and is opened in a substantially rectangular shape depending upon the shape of the secondary battery  1 . In the bottom face part of the battery installing part  102 , the electrode terminal  103  which comes into contact with the positive electrode terminal part  37  and the negative electrode terminal part  38  which are faced from the front face  1   c  of the secondary battery  1  is formed. 
     The battery holders  104 A,  104 B hold the secondary batteries  1 A,  1 B which are installed in the battery installing part  102 , and the battery holder  104 A holds the secondary battery  1 A as illustrated in  FIG. 36A , and the battery holder  104 B holds the secondary battery  1 B as illustrated in  FIG. 36B , respectively. The battery holders  104 A,  104 B have battery accommodating parts  105 A,  105 B for accommodating the secondary battery  1  therein and one pair of arm parts  106 A,  106 B which are continuously projected and formed from one pair of side faces of each of the battery accommodating parts  105 A,  105 B and which are rotatably supported by the battery charger main body  101 , respectively. Further, the battery holder  104 A is formed in such that the battery accommodating part  105 A is rotable towards the upper direction from the side of the front face of the upper face  101   a  of the battery charger main body  101  while using the base end parts of one pair of the arm parts  106 A as a rotation fulcrum; and the battery holder  104 B is formed such that it is rotatable towards the upper direction from the side of the back face of the upper face  101   a  of the battery charger main body  101  while using the base end parts of one pair of the arm parts  106 B as a rotation fulcrum. 
     The battery accommodating parts  105 A,  105 B are formed in a substantially rectangular box-like shape depending upon the shape of the secondary battery  1 , and one principal face thereof from which the secondary battery  1  is inserted into and detached and a lower face thereof in the side of the battery installing part  102  are opened. Furthermore, the battery accommodating parts  105 A,  105 B can be installed by inserting the secondary battery  1  from the side of the lower face  1   b.    
     The battery holders  104 A,  104 B are installed in such a manner that when the battery accommodating part  105 A and the battery accommodating part  105 B are rotated upwards the battery charger main body  101 , the opening sides of the respective principal faces are faced opposite to each other. That is, in the battery accommodating parts  105 A,  105 B, when installed on the upper face  101   a  of the battery charger main body  101 , each of the back face walls thereof is faced upwardly as illustrated in  FIG. 35 ; and when rotated upwardly, in the battery holder  104 A, the back face wall of the battery accommodating part  105 A is faced in the side of the back face of the battery charger main body  101  as illustrated in  FIG. 36A , whereas in the battery holder  104 B, the back face wall of the battery accommodating part  105 B is faced in the side of the front face of the battery charger main body  101  as illustrated in  FIG. 36B . In this way, the secondary battery  1 A which is installed in the battery holder  104 A and the secondary battery  1 B which is installed in the battery holder  104 B are installed in an opposite direction to each other with respect to the battery installing part  102  as provided on the upper face  101   a  of the battery charger main body  101 . 
     One pair of the arm parts  106 A,  106 B are rotatably supported while sandwiching the battery installing part  102  of the battery charger main body  101  therebetween; and when rotated in the side of the front face or in the side of back face of the battery charger main body  101 , they hold the battery holders  104 ,  104 B substantially flush with the upper face  101   a , whereas when rotated upwards the battery charger main body  101 , they raise up the battery holders  104 A,  104 B, thereby enabling the secondary battery  1  to be installed therein. 
     In one pair of the arm parts  106 A,  106 B, the respective base end parts are supported while sandwiching both end parts in the longitudinal direction of the battery installing part  102  as provided on the upper face  101   a  of the battery charger main body  101 . Furthermore, since the battery holder  104 A is formed so as to have a width narrower than the battery holder  104 B, the base end part of the arm part  106 A is supported in the battery charger main body  101  more inwardly than the base end part of the arm part  106 B. In this way, in the battery holder  104 A and the battery holder  104 B, when either one of them is rotated upwardly, the rotation of the other is inhibited. Thus, only one of the secondary battery  1 A or the secondary battery  1 B always comes into contact with the electrode terminal  103 . 
     In charging the secondary batteries  1 A,  1 B in which the positive electrode terminal part  37  and the negative electrode terminal part  38  are arranged in a position of substantial point symmetry for every function by using the foregoing battery charger  100 , either one of the battery holder  104 A or  104 B is rotated upwardly depending upon the position of the terminal of the secondary battery  1 . In the case where the battery holder  104 A is rotated upwardly (see  FIG. 36A ), the secondary battery  1 A is inserted into the battery accommodating part  105 A in such a manner that the lower face  1   b  is the insertion end face. In this way, in the secondary battery  1 A, the side of the front face  1   c  is installed in the battery installing part  102 , and the positive electrode terminal part  37  and the negative electrode terminal part  38  come into contact with the electrode terminal  103 , thereby achieving charging. 
     Incidentally, in the case where it is intended to insert the secondary battery  1 A from the side of the upper face  1   a , the insertion into the battery accommodating part  105 A is inhibited. Furthermore, in the case where the secondary battery  1 B is inserted into the battery holder  104 A, since the position of the positive electrode terminal part  37  and the negative electrode terminal part  38  is formed opposite such that it is rotated through 180 degrees, the positive electrode terminal part  37  and the negative electrode terminal part  38  do not come into contact with the electrode terminal  103  of the battery installing part  102 , whereby charging is not achieved. At this time, since the electrode terminal  103  comes into contact with the front face  36   c  of the top cover  36  made of a synthetic resin, it is prevented from the occurrence of direct contact with the metallic battery can  2 . Furthermore, in the case where the secondary battery  1 A is inserted inverted, since the electrode terminal  103  comes into contact with the back side  1   d  of the secondary battery  1 , charging is not achieved. At this time, since the electrode terminal  103  comes into contact with the first winding part  17  of the external label  15  as stuck in the bottom face part  7  of the battery can  2 , it is prevented from the occurrence of direct contact with the metallic battery can  2 . 
     Furthermore, in the case where the battery holder  104 B is rotated upwardly (see  FIG. 36B ), the secondary battery  1 B is inserted into the battery accommodating part  105 B in such a manner that the lower face  1   b  is the insertion end face. In this way, in the secondary battery  1 B, the side of the front face  1   c  is installed in the battery installing part  102 . Here, since the positive electrode terminal part  37  and the negative electrode terminal part  38  are formed in a position of substantial point symmetry against the secondary battery  1 A, when the secondary battery  1 B is inserted into the battery accommodating part  105 B in a reverse direction to the secondary battery  1 A as inserted into the battery accommodating part  105 A, the positive electrode terminal part  37  and the negative electrode terminal part  38  turn to the same positions as in the secondary battery  1 A with respect to the electrode terminal  103  of the battery installing part  102 . Accordingly, in the secondary battery  1 B, the positive electrode terminal part  37  and the negative electrode terminal part  38  come into contact with the electrode terminal  103 , thereby achieving charging. 
     Incidentally, in the case where it is intended to insert the secondary battery  1 B from the side of the upper face  1   a , the insertion into the battery accommodating part  105 B is inhibited. Furthermore, in the case where the secondary battery  1 A is inserted into the battery holder  104 B, since the position of the positive electrode terminal part  37  and the negative electrode terminal part  38  is formed opposite such that it is rotated through 180 degrees, the positive electrode terminal part  37  and the negative electrode terminal part  38  do not come into contact with the electrode terminal  103  of the battery installing part  102 , whereby charging is not achieved. At this time, since the electrode terminal  103  comes into contact with the front face  36   c  of the top cover  36  made of a synthetic resin, it is prevented from the occurrence of direct contact with the metallic battery can  2 . Furthermore, in the case where the secondary battery  1 B is inserted inverted, since the electrode terminal  103  comes into contact with the back side  1   d  of the secondary battery  1 , charging is not achieved. At this time, since the electrode terminal  103  comes into contact with the first winding part  17  of the external label  15  as stuck in the bottom face part  7  of the battery can  2 , it is prevented from the occurrence of direct contact with the metallic battery can  2 . 
     In the light of the above, in all of the secondary batteries  1 A,  1 B, since the positive electrode terminal part  37  and the negative electrode terminal part  38  turn to the same positions, the positive electrode terminal part  37  and the negative electrode terminal part  38  come into contact with the electrode terminal  103  as formed in the battery installing part  102 , thereby achieving charging. Thus, it is possible to commonly use the battery charger  100 . 
     Furthermore, in the battery charger  90 , since at the time of non-use, the battery holder  104  can be rotated in the side of the upper side  101   a  of the battery charger main body  101 , the battery charger  90  is excellent in portable properties and is able to prevent the breakage of the battery holder  104 . 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alternations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.