Non-aqueous electrolyte secondary cell

Abstract

A non-aqueous electrolyte secondary battery has a pressure-sensitive elastic element reliably operating at a desired operating pressure. The battery includes an outer can having an opening; an electrode assembly which is housed in the outer can and comprises a positive electrode having a positive electrode current collector and a negative electrode having a negative electrode current collector; a sealing plate sealing the opening; an external electrode terminal whose one end is engaged with the throughhole of the sealing plate and whose other end projects outside the sealing plate; and a pressure-sensitive elastic element which is disposed inside the sealing plate in the battery and deforms in accordance with an increase in the gas pressure in the battery, the external electrode terminal. The external electrode terminal includes therein a hole connecting the outside of the battery and the space in contact with the outer side of pressure-sensitive elastic element.

1 . A non-aqueous electrolyte secondary battery comprising: 
 an outer can having an opening;    an electrode assembly housed in the outer can, the electrode assembly comprising a positive electrode having a positive electrode current collector and a negative electrode having a negative electrode current collector;    a sealing plate sealing the opening; and    an external electrode terminal projecting outside the sealing plate, wherein    the external electrode terminal and the electrode assembly are electrically connected to each other via an electric conduction path, the electric conduction path having a pressure-sensitive elastic element halfway therein, the pressure-sensitive elastic element deforming in accordance with an increase in a gas pressure in the battery; and    the external electrode terminal includes therein a continuous hole connecting an outside of the battery and a space in contact with an outer side of the pressure-sensitive elastic element.    
     
     
         2 . The non-aqueous electrolyte secondary battery of  claim 1 , wherein 
 the pressure-sensitive elastic element deforms in accordance with the increase in the gas pressure in the battery so as to interrupt electrical connection between the external electrode terminal and the electrode assembly.    
     
     
         3 . The non-aqueous electrolyte secondary battery of  claim 2 , wherein 
 the sealing plate includes a gas relief valve, the gas relief valve being opened when the sealing plate is applied with a gas pressure higher than an operating gas pressure of the pressure-sensitive elastic element interrupting the electrical connection between the external electrode terminal and the electrode assembly.    
     
     
         4 . The non-aqueous electrolyte secondary battery of  claim 3 , wherein 
 the continuous hole is sealed by a membrane plug disposed halfway in the continuous hole, the membrane plug being made of a resin film.    
     
     
         5 . The non-aqueous electrolyte secondary battery of  claim 4 , wherein 
 the continuous hole is formed in the external electrode terminal and consists of a vertical hole and a horizontal hole, the vertical hole extending in an axial direction from an inner end of the battery, and the horizontal hole having an opening open to the outside of the battery and being communicated with the vertical hole.    
     
     
         6 . The non-aqueous electrolyte secondary battery of  claim 5 , wherein 
 the vertical hole is provided with an enlarged diameter portion whose inner diameter is enlarged in a shape of a ring; and    the membrane plug is formed in the enlarged diameter portion.    
     
     
         7 . The non-aqueous electrolyte secondary battery of  claim 1 , wherein 
 the sealing plate includes a gas relief valve, the gas relief valve being opened when the sealing plate is applied with a gas pressure higher than an operating gas pressure of the pressure-sensitive elastic element interrupting the electrical connection between the external electrode terminal and the electrode assembly.    
     
     
         8 . The non-aqueous electrolyte secondary battery of  claim 7 , wherein 
 the continuous hole is sealed by a membrane plug disposed halfway in the continuous hole, the membrane plug being made of a resin film.    
     
     
         9 . The non-aqueous electrolyte secondary battery of  claim 8 , wherein 
 the continuous hole is formed in the external electrode terminal and consists of a vertical hole and a horizontal hole, the vertical hole extending in an axial direction from an inner end of the battery, and the horizontal hole having an opening open to the outside of the battery and being communicated with the vertical hole.    
     
     
         10 . The non-aqueous electrolyte secondary battery of  claim 9 , wherein 
 the vertical hole is provided with an enlarged diameter portion whose inner diameter is enlarged in a shape of a ring; and    the membrane plug is formed in the enlarged diameter portion.    
     
     
         11 . The non-aqueous electrolyte secondary battery of  claim 1 , wherein 
 the continuous hole is sealed by a membrane plug disposed halfway in the continuous hole, the membrane plug being made of a resin film.    
     
     
         12 . The non-aqueous electrolyte secondary battery of  claim 11 , wherein 
 the continuous hole is formed in the external electrode terminal and consists of a vertical hole and a horizontal hole, the vertical hole extending in an axial direction from an inner end of the battery, and the horizontal hole having an opening open to the outside of the battery and being communicated with the vertical hole.    
     
     
         13 . The non-aqueous electrolyte secondary battery of  claim 12 , wherein 
 the vertical hole is provided with an enlarged diameter portion whose inner diameter is enlarged in a shape of a ring; and    the membrane plug is formed in the enlarged diameter portion.    
     
     
         14 . A method for producing a non-aqueous electrolyte secondary battery including an outer can having an opening; an electrode assembly housed in the outer can, the electrode assembly comprising a positive electrode having a positive electrode current collector and a negative electrode having a negative electrode current collector; a sealing plate sealing the opening; an external electrode terminal whose one end is engaged with a throughhole of the sealing plate and whose other end projects outside the sealing plate; and a pressure-sensitive elastic element deforming in accordance with an increase in a gas pressure in the battery, the external electrode terminal having therein a hole connecting an outside of the battery and a space in contact with an outer side of the pressure-sensitive elastic element, the method comprising: 
 a step of forming a membrane plug by injecting a resin solution into the vertical hole through an opening of the horizontal hole of the external electrode terminal, the resin solution containing a solvent and a resin dissolved or dispersed in the solvent, and then by volatilizing the solvent in the resin solution so as to form a resin film as the membrane plug.    
     
     
         15 . The method for producing a non-aqueous electrolyte secondary battery of  claim 14 , wherein 
 the step of forming the membrane plug is performed after the battery is assembled.    
     
     
         16 . The method for producing a non-aqueous electrolyte secondary battery of  claim 14 , wherein 
 the non-aqueous electrolyte secondary battery further includes a gasket having a throughhole disposed on an outer side of the sealing plate and an insulating plate having a throughhole disposed on an inner side of the sealing plate, the external electrode terminal having a flange parallel to an axial direction ; and    the method further comprises a step of swaging in which the gasket and the insulating plate are disposed on an outer surface and an inner surface, respectively, of the sealing plate in such a manner that the throughholes of the gasket and the insulating plate overlap with the throughhole of the sealing plate; then the external electrode terminal is fitted in the throughholes thus overlapped; and then the gasket, the sealing plate, and the insulating plate are vertically swaged both from a top end surface of the external electrode terminal and from the flange so as to be tightly fixed together and also to form an enlarged diameter portion in the hole of the external electrode terminal, the enlarged diameter portion being enlarged in a shape of a ring.    
     
     
         17 . The method for producing a non-aqueous electrolyte secondary battery of  claim 14 , wherein 
 the resin is a fluorine resin, and the solvent is xylene.    
     
     
         18 . The method for producing a non-aqueous electrolyte secondary battery of  claim 15 , wherein 
 the resin is a fluorine resin, and the solvent is xylene.    
     
     
         19 . The method for producing a non-aqueous electrolyte secondary battery of  claim 16 , wherein 
 the resin is a fluorine resin, and the solvent is xylene.