Abstract: A battery which has undergone initial charging and discharging is placed inside a sealed vessel, which is evacuated by a vacuum pump. After this evacuated state has been maintained for a while, the density of hydrogen gas within the sealed vessel is measured by a hydrogen density sensor, based on which the presence or absence of a gas escape from the battery is determined. The battery may be heated instead of subjecting it to charging and discharging.

Abstract: A coating composition is provided herein prepared by dispersing in water a film-forming component comprising about 60-99 wt. % of a powder containing as a main component one or more resins selected from polyethylene, polypropylene and their derivatives and about 1-40% by weight of a low molecular weight oxidized polyethylene and/or derivatives thereof. This coating can be used for coating various electrical parts, automobile parts, etc., and the coatings have an excellent appearance, good chemical resistance, high insulation properties and good water resistance.