ELEMENT MOUNTING SUBSTRATE, BATTERY, AND BATTERY MODULE

PROBLEM TO BE SOLVED: To provide a technology which achieves dielectric voltage performance and heat radiation performance of a component which generates heat by an electric current flowing therethrough during use.SOLUTION: An element mounting substrate 40 includes: a heat radiation substrate 10 which is formed by a material including at least one metal selected from a group composed of Al, Mg, and Ti; an insulation resin layer 42 laminated on the heat radiation substrate; and a wiring layer 44 which is laminated on the insulation resin layer and on which a power module is mounted. The heat radiation substrate 10 includes a random porous layer 14 which is provided so as to face the insulation resin layer 42 and in which long and thin cavities are formed in random directions.