Source:http://linkedlifedata.com/resource/umls/id/C0337088
UMD: Power supplies consisting of a set of electrochemical cells designed to store chemical energy and release it in the form of electrical power; the cells are usually connected in series. Single electrochemical cells used as electric power sources are also commonly called batteries. Every cell, regardless of its chemical composition, consists of a negative electrode, a positive electrode, an ionic conducting material (electrolyte), a separator to electrically isolate the electrodes, and a case; the electric current flows externally from the positive to the negative electrode . Batteries are usually described by some characteristic of their chemical composition (e.g., nickel-cadmium, zinc-carbon, lithium); they may be nonrechargeable (i.e., a primary battery) or rechargeable (i.e., a secondary battery). Batteries are mostly used in the field of medicine as power supplies for implantable medical devices (e.g., pacemakers, neural stimulators) and external medical instruments (e.g., defibrillators, pacemaker pr