PURPOSE: To prevent occurrence of combustion even when hydrogen and oxygen gases are leaked in the inner space of equipment from a battery and the mixture arrives at combustible concentration in the inner space of the equipment while it is being charged, by separating the inner space of the equipment into the battery housing section and the housing section of electric components that generate an arc acting as an ignition source using a partition wall.

CONSTITUTION: The housing section of a battery 7 and the housing of a motor 6 in the mainframe housing 1 are separated from each other by means of one end of a base 2 on which the battery 7 is mounted and a partition plate 35 that is retained by a pin provided at this one end. The partition plate 35 is made of a material that can absorb a soft shock. A pair of current supply springs 95 and 96 that are fixed to the base 2 using heat seal are inserted between the partition plate 35 and base 2 and a catalyst 61 is mounted on the surface of the partition plate 35 on the motor 7 side. For example, this catalyst 61 is formed by applying palladium on the surface of alumina so as to generate water by making hydrogen and oxygen to react with each other. Besides, for the housing section of the battery 7 out of both housing sections partitioned by the partition plate 35, an exhaust hole 62 is provided so as to connect it to the air.