To provide a new manufacturing method for a lithium ion secondary battery, a positive electrode mixture in particular, by solving such problem in a conventional method that if the mixing time is short, the distribution of a conductive agent is not uniformed although lowering of conductivity is suppressed, and if the mixing time is long, lowering of conductivity of AB is increased, when manufacturing the positive electrode mixture.
This positive electrode mixture consists of a positive electrode active material and two kinds of carbon black, AS and KB of a conductive agent, and the positive electrode active material, KB and a binding agent (NMP solution containing PVDF) are mixed for 60-120 minutes, preferably for 80-100 minutes in the primary mixing. In addition, AB, the binding agent and NMP are thrown in and are mixed for 20-60 minutes, preferably for 30-40 minutes in the secondary mixing. The distribution of the conductive agent in the positive electrode mixture is uniformed, conductivity and liquid retaining capability of an electrode is enhanced, and deterioration of a cycle caused by electrolyte is suppressed, by this manufacturing method. Thereby, the lithium ion secondary battery having a long cycle life can be obtained.
MORITA TERUYOSHI
HATANAKA TAKESHI
FURUYUI YASUTAKA
| JPH10312811A | 1998-11-24 | |||
| JPH09213309A | 1997-08-15 | |||
| JPS6130383B2 | 1986-07-12 |
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