Binder for lithium ion batteries, and electrode and separator using same

A method of producing a lithium ion battery comprising an electrode for at least one of a positive electrode and a negative electrode, the electrode comprising a composite nonaqueous binder of a cellulose nanofiber and a thermoplastic fluororesin, wherein the cellulose nanofiber is a cellulose having a fiber diameter (diameter) of 0.002 μm or more and 1 μm or less, a fiber length of 0.5 μm or more and 10 mm or less, and an aspect ratio (fiber length of the cellulose nanofiber/fiber diameter of the cellulose nanofiber) of 2 or more and 100,000 or less,

• the method comprising a step (F) of
• sealing a stacked or wound electrode group with a separator interposed between the positive electrode and the negative electrode in a battery case together with an electrolytic solution containing lithium hexafluorophosphate and aprotic carbonates,
• thereafter heating the battery case to raise the temperature thereof to 50° C. or higher and 120° C. or lower,
• applying a pressure from outside of the battery case perpendicularly to an extension direction of the electrode,
• thereby integrating the separator with the electrode.

A method of producing a lithium ion battery comprising a separator, the separator comprising a composite nonaqueous binder of a cellulose nanofiber and a thermoplastic fluororesin, wherein the cellulose nanofiber is a cellulose having a fiber diameter (diameter) of 0.002 μm or more and 1 μm or less, a fiber length of 0.5 μm or more and 10 mm or less, and an aspect ratio (fiber length of the cellulose nanofiber/fiber diameter of the cellulose nanofiber) of 2 or more and 100,000 or less,

• the method comprising a step (F) of
• sealing a stacked or wound electrode group with a separator interposed between a positive electrode and a negative electrode in a battery case together with an electrolytic solution containing lithium hexafluorophosphate and aprotic carbonates,
• thereafter heating the battery case to raise the temperature thereof to 50° C. or higher and 120° C. or lower,
• applying a pressure from outside of the battery case perpendicularly to an extension direction of the electrode,
• thereby integrating the separator with the electrodes.