A thermoelectric battery, in particular for a heart pacemaker

摘要

1351630 Thermoelectric devices UNITED KINGDOM ATOMIC ENERGY AUTHORITY 13 Nov 1972 [20 Dec 1971] 59174/71 Heading HlK A thermoelectric battery has an assembly comprising a heat source, a heat sink and a thermoelectric unit mounted within a casing by means of a resilient arrangement which presses the heat sink against a thermally conductive mass attached to the casing, the adjacent surfaces of the heat sink and the mass being shaped to allow the thermoelectric assembly to rock relative to the casing under the action of acceleration forces. As shown, the assembly comprises a heat source 4 and a heat sink 5 between which extends a thermopile 6. The heat source 4 consists of a casing 17, 18 surrounding a can 16 containing Pu-238. One end of the thermopile 6 is secured to the heat source (via a piece 23 of insulating cloth) and its opposite end is similarly secured to the heat sink 5 which comprises an aluminium alloy disc the upper face of which is frusto-conical with a large vertical angle. The heat sink is pressed against the massive end 7 of the outer casing by means of a prestressed spring 8 via a sleeve 11. The other end of the spring bears against an annular Ta ring 33 which together with tube 34 and disc 25 also of Ta form a radiation shield surrounding the heat source. A rubber buffer ring 30 may surround the heat source or alternatively a ring 31 may be attached to the inside of the casing. The outer casing 2 of the device is of stainless steel and is filled with an inert gas, e.g. Xe. If the device is subjected to lateral acceleration forces sufficient to overcome the prestressing of the spring the heat sink 5 rolls on the end of the casing, motion being limited by the rubber buffer 30 (or 31). When the acceleration force decreases the spring returns the assembly to its initial position this being achieved without overshoot by virtue of the central flat portion of the heat sink top surface. If the acceleration force is in the longitudinal direction and is sufficient to overcome its prestressing the spring is compressed and the heat sink moves away from the end of the housing. The distance A between the end 18 of the heat source and the radiation shield is arranged to be less than the distance B between the edge of the sleeve 11 and a stop 9 on the casing so that longitudinal displacement of the assembly results in an impact which applies a compressive rather than a tensile stress to the thermopile.