NOVELTY - The device has a promethium powder device (1) perpendicularly placed to a bottom part of an inner layer jacket (5). A middle layer optical-electrical conversion material (3) is overlapped on a lower layer optical-electrical conversion material (12). An upper layer lower optical-electrical conversion material (10) is overlapped on the middle layer optical-electrical conversion material. An anode material is provided with a carbon rod (7) and a copper cap (8), where the carbon rod and the copper cap are vertically inserted above the middle layer optical-electrical conversion material.    USE - Promethium powder battery device.    ADVANTAGE - The device has high efficiency, long service life, high specific energy, security, economy, and wide usage. The device utilizes the promethium powder with less self attenuation, so that the device radiates with the sheet promethium powder, to enable the prolonged action fluorescent substance to emit light, thus improving effective utilization of promethium powder beta ray. The device fully absorbs the energy by the photoelectric effect of multi-stage high conversion, to enable the photoelectric effect to generate electrical energy as much as possible, and hence improving total efficiency of the device.    DETAILED DESCRIPTION - The upper layer lower optical-electrical conversion material is a layer of selenium, sodium, and copper oxide alloy sheet whose one face faces to the promethium powder is coated with rubidium powder, and the middle layer optical-electrical conversion material is formed by multilayer selenium, sodium, and copper oxide alloy in crystalline form stack.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of a promethium powder battery device.    Promethium powder (1)    Middle layer optical-electrical conversion material (3)    Inner layer jacket (5)    Carbon rod (7)    Copper cap (8)    Upper layer lower optical-electrical conversion material (10)    Lower layer optical-electrical conversion material (12)