Lithium secondary battery

Abstract

A lithium secondary battery includes a battery case, and an internal electrode body contained in the battery case and including a positive electrode and a negative electrode wound through a separator film made of porous polymer, and uses a nonaqueous organic electrolyte. Opposing pressure release mechanisms are disposed at both ends of the battery case in the winding direction of the positive electrode and the negative electrode. The lithium secondary battery is simple in fabrication, has small internal resistance, and is superior in safety.

What is claimed is:  
     
         1 . A lithium secondary battery, comprising: 
 a battery case;    an internal electrode body contained in the battery case and including a positive electrode, a negative electrode, and a separator made of porous polymer, the positive electrode and the negative electrode being wound through the separator so that the positive electrode and the negative electrode are not brought into direct contact with each other;    an organic electrolyte contained in the battery case; and    a pressure release mechanism disposed at each of both end portions of the battery case in a winding direction of the positive electrode and the negative electrode.    
     
     
         2 . A lithium secondary battery according to  claim 1 , wherein the battery case is cylinder-shaped.  
     
     
         3 . A lithium secondary battery according to  claim 1 , wherein at least one of said pressure release mechanism is disposed at each of both end portions of the battery case.  
     
     
         4 . A lithium secondary battery, comprising: 
 a battery case;    an internal electrode body contained in the battery case and including a positive electrode, a negative electrode, and a separator made of porous polymer, the positive electrode and the negative electrode being laminated through the separator so that the positive electrode and the negative electrode are not brought into direct contact with each other;    an organic electrolyte contained in the battery case; and    at least one pressure release mechanism disposed on a side surface, perpendicular to flat surfaces of said positive electrode and said negative electrode, of the battery case.    
     
     
         5 . A lithium secondary battery according to  claim 4 , wherein said pressure release mechanism is disposed on each of at least one pair of facing side surfaces of the battery case.  
     
     
         6 . A lithium secondary battery according to  claim 1 , wherein when battery capacity is C (Ah) and the total area of opening portions where the pressure release mechanisms operate is S (cm 2 ), the relation of 0.05≦S/C≦2 is established.  
     
     
         7 . A lithium secondary battery according to  claim 4 , wherein when battery capacity is C (Ah) and the total area of opening portions where the pressure release mechanisms operate is S (cm 2 ), the relation of 0.05≦S/C≦2 is established.  
     
     
         8 . A lithium secondary battery according to  claim 1 , wherein an operational pressure of the pressure release mechanism is 2 to 10 kg/cm 2 .  
     
     
         9 . A lithium secondary battery according to  claim 4 , wherein an operational pressure of the pressure release mechanism is 2 to 10 kg/cm 2 .  
     
     
         10 . A lithium secondary battery according to  claim 1 , wherein a difference in operational pressures of the installed pressure release mechanisms is 8 kg/cm 2  or less.  
     
     
         11 . A lithium secondary battery according to  claim 4 , wherein a difference in operational pressures of the installed pressure release mechanisms is 8 kg/cm 2  or less.  
     
     
         12 . A lithium secondary battery, comprising: 
 a battery case;    an internal electrode body contained in the battery case and including a positive electrode, a negative electrode, and a separator made of porous polymer, the positive electrode and the negative electrode being wound through the separator so that the positive electrode and the negative electrode are not brought into direct contact with each other;    an organic electrolyte contained in the battery case; and    at least one pressure release mechanism disposed in one end portion of the battery case in a winding direction of said internal electrode body, 
 wherein when the total area of an opening portion where the pressure release mechanism operates is S (cm 2 ) and capacity of the lithium battery is C (Ah), the relation of 0.5≦S/C≦2 is established.  
   
     
     
         13 . A lithium secondary battery, comprising: 
 a battery case;    an internal electrode body contained in the battery case and including a positive electrode, a negative electrode, and a separator made of porous polymer, the positive electrode and the negative electrode being laminated through the separator so that the positive electrode and the negative electrode are not brought into direct contact with each other;    an organic electrolyte contained in the battery case; and    at least one pressure release mechanism disposed on a side surface perpendicular to flat surfaces of said positive electrode and said negative electrode or on each of at least two of not facing side surfaces, of the battery case, 
 wherein when the total area of an opening portion where the pressure release mechanism operates is S (cm 2 ) and capacity of the lithium battery is C (Ah), the relation of 0.5≦S/C≦2 is established.  
   
     
     
         14 . A lithium secondary battery according to  claim 1 , wherein the pressure release mechanism includes a metal foil which bursts to release an internal pressure of the battery to an outside pressure.  
     
     
         15 . A lithium secondary battery according to  claim 4 , wherein the pressure release mechanism includes a metal foil which bursts to release an internal pressure of the battery to an outside pressure.  
     
     
         16 . A lithium secondary battery according to  claim 12 , wherein the pressure release mechanism includes a metal foil which bursts to release an internal pressure of the battery to an outside pressure.  
     
     
         17 . A lithium secondary battery according to  claim 13 , wherein the pressure release mechanism includes a metal foil which bursts to release an internal pressure of the battery to an outside pressure.  
     
     
         18 . A lithium secondary battery according to  claim 1 , wherein the pressure release mechanism includes a groove portion disposed in a metal plate, the groove portion being burst so that an internal pressure of the battery is released to an outside pressure.  
     
     
         19 . A lithium secondary battery according to  claim 4 , wherein the pressure release mechanism includes a groove portion disposed in a metal plate, the groove portion being burst so that an internal pressure of the battery is released to an outside pressure.  
     
     
         20 . A lithium secondary battery according to  claim 12 , wherein the pressure release mechanism includes a groove portion disposed in a metal plate, the groove portion being burst so that an internal pressure of the battery is released to an outside pressure.  
     
     
         21 . A lithium secondary battery according to  claim 13 , wherein the pressure release mechanism includes a groove portion disposed in a metal plate, the groove portion being burst so that an internal pressure of the battery is released to an outside pressure.  
     
     
         22 . A lithium secondary battery according to  claim 14 , wherein the metal foil disposed at a positive side is made of aluminum, and the metal foil disposed at a negative side is made of copper or nickel.  
     
     
         23 . A lithium secondary battery according to  claim 15 , wherein the metal plate disposed at a positive side is made of aluminum, and the metal plate disposed at a negative side is made of copper or nickel.  
     
     
         24 . A lithium secondary battery according to  claim 16 , wherein the metal foil disposed at a positive side is made of aluminum, and the metal foil disposed at a negative side is made of copper or nickel.  
     
     
         25 . A lithium secondary battery according to  claim 17 , wherein the metal plate disposed at a positive side is made of aluminum, and the metal plate disposed at a negative side is made of copper or nickel.  
     
     
         26 . A lithium secondary battery according to  claim 18 , wherein the metal plate disposed at a positive side is made of aluminum, and the metal plate disposed at a negative side is made of copper or nickel.  
     
     
         27 . A lithium secondary battery according to  claim 19 , wherein the metal plate disposed at a positive side is made of aluminum, and the metal plate disposed at a negative side is made of copper or nickel.  
     
     
         28 . A lithium secondary battery according to  claim 20 , wherein the metal plate disposed at a positive side is made of aluminum, and the metal plate disposed at a negative side is made of copper or nickel.  
     
     
         29 . A lithium secondary battery according to  claim 21 , wherein the metal plate disposed at a positive side is made of aluminum, and the metal plate disposed at a negative side is made of copper or nickel.  
     
     
         30 . A lithium secondary battery according to  claim 12 , wherein an area of an opening of the pressure release mechanism is not less than 0.1 cm 2 .  
     
     
         31 . A lithium secondary battery according to  claim 13 , wherein an area of an opening of the pressure release mechanism is not less than 0.1 cm 2 .  
     
     
         32 . A lithium secondary battery according to  claim 1 , wherein battery capacitance is not less than 5 Ah.  
     
     
         33 . A lithium secondary battery according to  claim 4 , wherein battery capacitance is not less than 5 Ah.  
     
     
         34 . A lithium secondary battery according to  claim 12 , wherein battery capacitance is not less than 5 Ah.  
     
     
         35 . A lithium secondary battery according to  claim 13 , wherein battery capacitance is not less than 5 Ah.  
     
     
         36 . A lithium secondary battery according to  claim 1 , wherein the battery is used for an electric vehicle or a hybrid electric vehicle.  
     
     
         37 . A lithium secondary battery according to  claim 4 , wherein the battery is used for an electric vehicle or a hybrid electric vehicle.  
     
     
         38 . A lithium secondary battery according to  claim 12 , wherein the battery is used for an electric vehicle or a hybrid electric vehicle.  
     
     
         39 . A lithium secondary battery according to  claim 13 , wherein the battery is used for an electric vehicle or a hybrid electric vehicle.