Lithium ion secondary battery

Electrode assemblies easily impregnated with an electrolyte are provided. A sealing tape attached to the outer circumference of the electrode assembly comprises a material having an affinity for the electrolyte. Alternatively, the entire sealing tape or a portion of the tape is coated with the material. In another alternative, the surface of the sealing tape is rough, thereby improving wetting of the tape by the electrolyte and diffusion of the electrolyte into the tape. In another embodiment, first and second insulating plates comprise a material having an affinity for the electrolyte. In another alternative, the insulating plates comprise a mixture of a material having an affinity for the electrolyte and polypropylene or polyethylene. Alternatively, the surfaces of the insulating plates are coated with the material or with a surfactant that reduces the surface tension of the electrolyte.