Batteries used to Power Implantable Biomedical Devices

Likely developments awaiting the science and technology of next-generation lithium batteries form the focus of this article. New anode materials based on nano-structured carbons and lithium-alloying metals, novel eco-friendly cathode materials, safe and non-flammable aprotic electrolytes, and polymer electrolytes are discussed. Possible scenarios for improvements in existing or presumed battery active materials are suggested. Advances in the science and technology of lithium batteries are previewed with a prognosis of challenges and opportunities in the development of marketable materials and products.

Materials for next-generation lithium batteries

The history of biomedical implantable devices is traced from its beginning in the late 1950s to its status today. The role of industry in making this development possible is highlighted. Special emphasis is placed on the early history of the implantable cardiac pacemaker, the first implantable, electronic biomedical device. Implantable drug delivery systems and the implantable defibrillator are also discussed. Implantable devices of the future are briefly described. >

History of implantable devices

A solid cathode liquid organic electrolyte lithium cell for delivering high current pulses comprising a casing, a cathode structure inthe casing comprising a plurality of plates in spaced apart relation, a lithium anond comprising a plurality of anode sections interposed between the cathode plates, a non-aqueous liquid organic electrolyte comprising the combination of a lithum dalt and an organic solvent in the casing operatively contacting the anode and the cathode an electrical connection provided to the anode and an electrical connection provided to the cathode. In accordance with one aspect of the invention the cathode includes as active material Ag x V 2 O y where x is in the range from about 0.5 to about 2.0 and y is in the range from about 4.5 to about 6.0 which advantageously has high volumetric capacity and high rate capability with the result that the cell of the present invention delivers high capacity, shows good current pulsing behavior at various levels of discharge, and has a sloping discharge cause enabling end of life to be predicted. In accordance with another aspect of the present invention, the anode comprises a continuous elongated lithium element enclosed within a separator and folded into a plurality of sections interposed between the cathode plates, each of which individually is enclosed within separator material thereby enhancing the reliability of the cell. The cell of the present invention finds advantageous use as a power source for an implantable cardiac defibrillator.

Non-agueous lithium battery

An organic electrolyte cell is disclosed which comprises an anode (1) mainly composed of Li and containing Al and a cathode (3) mainly composed of manganese dioxide, wherein the amounts for Li, Al and manganese dioxide are determined such that they are included within a region surrounded by : where x represents the ratio t2/t1 between the thickness t1 for Li and the thickness t2 for Al for expressing the ratio of the amounts between Li and Al constituting the anode; and y represents the weight ratio (Li/MnO 2 ) between Li and manganese dioxide whereby the increase in the internal resistance at the final stage of the discharge is suppressed, so that the cell capacity can be utilized effectively to the last

Organic electrolyte cell

An electrochemical cell incorporating cathode materials comprising at least one metal oxide, at least one metal, or mixture of metals or metal oxides incorporated in the matrix of a host metal oxide. The cathode materials of this invention are constructed by the chemical addition, reaction, or otherwise intimate contact of various metal oxides and/or metal elements during thermal treatment in mixed states. The materials thereby produced contain metals and oxides of the groups IB, IIB, IIIB, IVB, VB, VIB, VIIB, and VIII, which includes the noble metals and/or their oxide compounds. The incorporation of the metal oxides, metals or mixtures thereof substantially increases the discharge capacity and the overall performance of the cathode materials.

Charles C. Liang

Papers

Metal oxide composite cathode material for high energy density batteries