Processing device of nonaqueous electrolyte secondary battery and manufacturing method thereof

Abstract

To melt and diffuse metallic foreign bodies immixed in electrodes of a nonaqueous electrolyte secondary battery before initial charging, electrodes ( 18 ) wound with a separator ( 24 ) between a cathode plate ( 20 ) and an anode plate ( 22 ) are placed in a battery case ( 16 ) and the battery case ( 16 ) is filled with an electrolyte. After the case has been filled, the electrolyte is allowed to permeate into the electrodes (S 14 ). Then, the electrolyte-filled battery ( 14 ) is placed in a processing device ( 10 ), and fixed by means of a surface pressure between at least 0.1 MPa and 5.0 MPa (S 16 ). Thereafter, the cathode potential is adjusted and held for a period of one hour and 35 hours (S 18 ) while the battery remains fixed, after which the pre-initial charging process is terminated (S 20 ).

1 . A processing device for a nonaqueous electrolyte secondary battery having electrodes accommodated together with a nonaqueous electrolyte in a battery case, the electrodes including a cathode plate and an anode plate arranged on opposite sides of a separator, for melting and diffusing metallic foreign bodies immixed in the electrodes, the processing device comprising:
 a space reducing unit for reducing a space in the uncharged electrodes, to thereby place the nonaqueous electrolyte secondary battery in a space-reduced state; and   a holding unit for holding a cathode potential at a melting potential of the metallic foreign bodies for a predetermined period of time in the space-reduced state, the melting potential of the metallic foreign bodies being lower than a charge-discharge cathode potential for use in charging and discharging the nonaqueous electrolyte secondary battery.   
     
     
         2 . The processing device for a nonaqueous electrolyte secondary battery according to  claim 1 , wherein the space reducing unit is a battery fixing unit for fixing the battery case on an outer surface thereof by applying a predetermined surface pressure sufficient to bring the cathode plate into contact with the metallic foreign bodies. 
     
     
         3 . The processing device for a nonaqueous electrolyte secondary battery according to  claim 2 , wherein the battery fixing unit employs a surface pressure between 0.1 MPa and 5.0 MPa as the predetermined surface pressure. 
     
     
         4 . The processing device for a nonaqueous electrolyte secondary battery according to  claim 2 , wherein the battery fixing unit further comprises a battery heating unit for heating the nonaqueous electrolyte secondary battery. 
     
     
         5 . The processing device for a nonaqueous electrolyte secondary battery according to  claim 1 , wherein the holding unit holds a cathode potential of the nonaqueous electrolyte secondary battery in an open-circuit state in a case that the metallic foreign bodies are assumed to be of iron. 
     
     
         6 . A method for manufacturing a nonaqueous electrolyte secondary for melting and diffusing metallic foreign bodies immixed in a nonaqueous electrolyte secondary battery having electrodes accommodated together with a nonaqueous electrolyte in a battery case, the electrodes including a cathode plate and an anode plate arranged on opposite sides of a separator, the method comprising:
 a space reducing step of reducing a space in the uncharged electrodes, to thereby place the nonaqueous electrolyte secondary battery in a space-reduced state; and   a holding step of holding a cathode potential at a melting potential of the metallic foreign bodies for a predetermined period of time in the space-reduced state, the melting potential of the metallic foreign bodies being lower than a charge-discharge cathode potential for use in charging and discharging the nonaqueous electrolyte secondary battery.   
     
     
         7 . The method for manufacturing a nonaqueous electrolyte secondary according to  claim 6 , wherein the space reducing step is a battery fixing step comprising fixing the battery case on an outer surface thereof by applying a predetermined surface pressure sufficient to bring the cathode plate into contact with the metallic foreign bodies. 
     
     
         8 . The manufacturing method for a nonaqueous electrolyte secondary battery according to  claim 6 , wherein the space reducing step is a battery depressurizing step comprising reducing pressure in the battery case. 
     
     
         9 . The method for manufacturing a nonaqueous electrolyte secondary battery according to  claim 6 , wherein the space reducing step is a battery heating step comprising heating the battery, based on a predetermined heating condition, after the battery fixing step, and thereafter releasing the battery from the fixed state. 
     
     
         10 . The manufacturing method for a nonaqueous electrolyte secondary battery according to  claim 6 , wherein, at the holding step, a cathode potential of the nonaqueous electrolyte secondary battery in an open-circuit state is maintaining, in a case that the metallic foreign bodies are assumed to be of iron.