supply of electrical energy

Abstract

Device (101) for supplying electrical energy to a power-consuming portable device (102), wherein the portable device (102) is designed for use in potentially explosive atmospheres in which restrictions apply with regard to maximum permissible surface temperatures during normal operation and in fault conditions that cause a short circuit, comprising: - a housing which can be arranged in or attached to the portable device (102); - a rechargeable lithium-ion cell (402) which is housed in the housing; - a current-limiting control circuit which is housed in the housing; and - a heat-absorbing material which is arranged in the housing, wherein: - the rechargeable lithium-ion cell (402) is substantially cylindrical;- the heat-absorbing material is formed by a metal tube (501) designed to encase the lithium-ion cell (402); - the metal tube (501) is composed of longitudinal profiles (601, 701; 901, 901, 903; 1101; 1102, 1104); - the heat-absorbing material is pressed into close thermal contact with the lithium-ion cell (402) to facilitate heat transfer from the lithium-ion cell (402) to the heat-absorbing material; and - the heat-absorbing material is designed to absorb sufficient heat from the lithium-ion cell (402) to keep all accessible surfaces below a predetermined temperature.