PROBLEM TO BE SOLVED: To provide a battery capable of preventing or recovering deterioration, and bringing out charge and discharge performance to the maximum or maintaining the charge and discharge performance for a long time.SOLUTION: Attention is paid to a reaction product (also called as fur) generated on an electrode surface as factors of generation of various abnormalities and deterioration of an electrochemical cell such as a lithium ion secondary battery. An electrochemical device is provided with means for applying an electrical stimulus to the reaction product, in concrete terms, for applying a voltage of a reverse pulse so as to remove the reaction product.
