<p>A battery case for effectively dissipating the heat from 36V car batteries is disclosed. The battery case comprises an electrolytic bath having a plurality of compartments, and a lid covering the top of the electrolytic bath. The compartments are defined by a central partition and a plurality of cell partitions arranged perpendicular to the central partition. The electrolytic bath is provided with a plurality of vertical through-holes and a transversal through-hole for dissipating the heat. The vertical and transversal through-holes pass through the electrolytic bath in a vertical and transversal direction respectively, and are inter-connected. The lid is provided with a plurality of upper openings, the positions of which correspond to those of the vertical through-holes. The battery case is placed on a tray and mounted in the engine room of vehicles. A plurality of lower openings is formed on the tray, the positions of which correspond to those of the vertical through-holes.</p>
