Abstract: A locking device which can be unlocked even in the dark by a simple operation such as inserting a card key, wherein a slit is provided in a casing for receiving the card key, a slider is provided movably inside the casing, a tumbler is inserted movably into the slider and protruding its point into the slit, and an engaging projection is provided on the tumbler. The engaging projection comes into engagement with a groove provided on the bottom of the casing so that the movement of the slider is prevented for completing a locking process. A card key provided with a plurality of holes of different diameters is inserted into the slit for moving the tumbler to an unlocking position, so that the engaging projection is disengaged from the groove to allow the slider to move in a predetermined direction for completing an unlocking process.

Abstract: A sodium-sulfur cell block having a plurality of sodium-sulfur cells is attached to, and held by, common terminals at both ends of the cells and in the long axes directions of the cells. In order to absorb thermal stress generated between the cells and the common terminals, at least one end is cantilevered at said common terminal.