Battery and method for manufacturing the same

Abstract

A battery having a collecting structure that can reduce internal resistance of the battery and a structure that allows easy manufacturing of the battery by the following processes is provided. An enlarged portion is formed near an opening end of a battery case and a supporting ledge is provided on the inner surface of the lower end of the enlarged portion. A collector of one polarity is bonded to an electrode plate group. A connection lead is bonded to the collector at one end and is bonded to a lower surface of a sealing member at the other end. An insulation gasket is mounted to a peripheral edge portion of the sealing member from a side opposite to the collector. The peripheral edge portion of the sealing member is supported by the supporting ledge with the insulation gasket interposed therebetween. Then, the peripheral edge portion of the sealing member is horizontally fastened and securely held via the insulation gasket by caulking the opening end of the battery case and performing a process for reducing the diameter of the enlarged portion.

1 . A method for manufacturing a battery comprising the steps of:
 accommodating a spiral electrode plate group in a cylindrical battery case having a bottom, the battery case having an enlarged portion formed close to an opening end thereof and an annular supporting ledge on an inner surface of a lower end of the enlarged portion, a collector of one polarity being bonded to an upper end of the spiral electrode plate group while a collector of another polarity is bonded to a lower end thereof;   bonding one end of a connection lead to the collector of the one polarity in an arrangement in which a notch formed at the one end of the connection lead is in agreement with a part of a hole edge of an electrolyte-injection hole at a center of the collector of the one polarity, and then bending the connection lead at a portion near a portion bonded to the collector of the one polarity in such a manner that the connection lead stands vertically;   bonding another end of the standing connection lead to a portion of a sealing member arranged parallel to the standing connection lead, the portion of the sealing member being below a vent opening positioned at a center of the sealing member;   injecting electrolyte into the battery case through the electrolyte-injection hole of the collector of the one polarity;   rotating the sealing member while the connection lead is bent to form a folded portion between the one end and the other end thereof, inserting the sealing member thus arranged into the opening of the battery case, and latching a peripheral edge portion of the sealing member on the supporting ledge of the battery case with an insulation gasket interposed therebetween; and   fastening the peripheral edge portion of the sealing member in a horizontal direction with the insulation gasket interposed therebetween by performing caulking of an opening end of the battery case inward and reducing a diameter of the enlarged portion.   
     
     
         2 . A battery comprising a cylindrical metal battery case having a bottom and an electrode plate group accommodated in the battery case, the electrode plate group comprising a strip-shaped positive electrode plate and a strip-shaped negative electrode plate spirally wound with a separator interposed therebetween, wherein
 an opening at an upper end of the battery case is sealed with a sealing member with an insulation gasket interposed therebetween,   an enlarged portion is formed above an upper end of the electrode plate group on the side close to an opening end of the battery case, and an annular supporting ledge is formed on an inner surface of a lower end of the enlarged portion,   a collector having one polarity is bonded to an end of the electrode plate having the one polarity that projects upward from the electrode plate group,   one end of a connection lead is bonded to the collector of the one polarity, and the other end of the connection lead is bonded to a lower face of the sealing member,   the insulation gasket is mounted to a peripheral edge portion of the sealing member from a side opposite to the collector of the one polarity,   the peripheral edge portion of the sealing member is supported by the supporting ledge with the insulation gasket interposed therebetween, and   the peripheral edge portion of the sealing member is fastened in a horizontal direction with the insulation gasket interposed therebetween by performing caulking of the opening end of the battery case inward and reducing a diameter of the enlarged portion.   
     
     
         3 . The battery according to  claim 2 , wherein
 the insulation gasket comprises a holding inner wall face with which a peripheral end face of the sealing member is to fit; a supporting bottom portion, extending below the holding inner wall face, operable to support the peripheral edge portion of the sealing member from beneath; and a guide tapered face serving as an introduction port for mounting of the sealing member, the guide tapered face having a shape that broadens downward from the supporting bottom portion, wherein the holding inner wall face, the supporting bottom portion, and the guide tapered face are formed integrally.   
     
     
         4 . The battery according to  claim 3 , wherein
 a length of the supporting bottom portion projecting inward from the holding inner wall face is set in a range from 0.2 mm to 0.4 mm.   
     
     
         5 . The battery according to  claim 3 , wherein
 the insulation gasket comprises a covering portion formed integrally therewith, the covering portion extending inward from an upper end of the holding inner wall face at an angle.   
     
     
         6 . The battery according to  claim 3 , wherein
 the insulation gasket comprises a covering portion formed integrally therewith, the covering portion extending inward from an upper end of the holding inner wall face parallel to a lower surface of the insulation gasket.   
     
     
         7 . The battery according to  claim 2 , wherein
 the insulation gasket has a cross-sectional shape that broadens toward a position at which the collector is to be arranged when the insulation gasket is mounted on the sealing member, before the insulation gasket is mounted to the peripheral edge portion of the sealing member.   
     
     
         8 . The battery according to  claim 2 , wherein
 the connection lead is formed by a rectangular plate of electrically conductive material, and comprises: a connection base portion bonded to a substantially central portion of the collector of one polarity being extending outward; a standing portion be extending upward from the connection base portion; and a connected portion, extending parallel to the connection base portion from an upper end of the standing portion toward a periphery of the sealing member, being bonded to a lower surface of the sealing member.   
     
     
         9 . The battery according to  claim 2 , wherein
 the connection lead is formed by a rectangular plate of electrically conductive material, and comprises: a connection base portion bonded to a substantially central portion of the collector of one polarity and being extending outward; a pair of standing portions be extending upward from both ends of the connection base portion, respectively; and a pair of connected portions, extending parallel to the connection base portion from upper ends of the pair of standing portions toward a periphery of the sealing member, respectively, being bonded to a lower surface of the sealing member, respectively.   
     
     
         10 . A method for manufacturing a battery comprising the steps of:
 bonding a collector of one polarity and a collector of another polarity to upper and lower ends of an electrode plate group, respectively;   bonding a connection base portion of a connection lead to the collector of the one polarity before or after the bonding of the collector of the one polarity to the electrode plate group;   bonding a connected portion of the connection lead to a lower surface of a peripheral edge portion of a filter portion of a sealing member by resistance welding, the connected portion being formed continuously from the connection base portion with a standing portion interposed therebetween;   mounting an insulation gasket to the peripheral edge portion of the filter portion from a side opposite to the collector;   accommodating the electrode plate group in a cylindrical battery case having a bottom, and an enlarged portion close to an opening end thereof and an annular supporting ledge formed on an inner surface of a lower end of the enlarged portion, and placing the peripheral edge portion of the filter portion on the supporting ledge with the insulation gasket interposed therebetween;   caulking the opening end of the battery case inward and reducing a diameter of the enlarged portion to horizontally fasten and secure the peripheral edge portion of the sealing member with the insulation gasket interposed therebetween;   injecting electrolyte into the battery case through an electrolyte-injection hole of the collector of the one polarity; and   assembling the sealing member by bonding a cap terminal to the filter portion with a safety vent body interposed therebetween.   
     
     
         11 . The method for manufacturing a battery according to  claim 10 , wherein
 in welding of the connected portion of the connection lead to the peripheral edge portion of the filter portion of the sealing member by resistance welding, a current is applied across welding electrodes while one of the welding electrodes, which has an arc-like shape corresponding to the peripheral edge portion of the filter portion, is brought into contact with a lower surface of the connected portion and the other of the welding electrodes, which has a ring-like shape, is brought into contact with an upper surface of the peripheral edge portion of the filter portion.   
     
     
         12 . The method for manufacturing a battery according to  claim 10 , wherein
 the insulation gasket having such a cross-sectional shape that broadens toward a position at which the collector is to be arranged when the insulation gasket is mounted on the sealing member, before being mounted to the peripheral edge portion of the sealing member is used,   the insulation gasket is laid over a bonded portion of the filter portion that has been bonded to the electrode plate group via the collector and the connection lead in advance, from a side opposite to the collector, and   the insulation gasket and the electrode plate group are inserted together into the battery case while the insulation gasket is deformed in such a manner that a portion thereof projecting outward is pursed inward.