Patents by Inventor William D. Helgeson

William D. Helgeson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method for making an electrochemical cell
    Patent number: 5455123
    Abstract: A method for making a primary cell comprising a lithium anode and an iodine containing cathode. The cell is first subjected to a preliminary conditioning at a predetermined time/temperature to effect a reduction in the impedance of the cell followed by cell discharge of at least 2 mAh per cm.sup.2 of the lithium anode surface prior to use or extended storage of the cell. The resulting primary cell has reduced variation in cell voltage and resistance and slower and more consistent self-discharge characteristics.
    Type: Grant
    Filed: February 14, 1994
    Date of Patent: October 3, 1995
    Assignee: Medtronic, Inc.
    Inventors: William D. Helgeson, Craig L. Schmidt, Bernard F. Heller, Daniel D. Michels
  • Lithium-iodine electrochemical cells with improved end of life characteristics
    Patent number: 5209994
    Abstract: In lithium iodine electrochemical cells, control of polyvinylpyridine film thickness and/or polyvinylpyridine film surface area coverage and/or control of the quantity thereof on or with respect to the lithium anode operative surface directly affects cell voltage characteristics during discharge, allowing the tailoring of the voltage characteristics near cell end-of-life (EOL) in a useful way.
    Type: Grant
    Filed: December 13, 1990
    Date of Patent: May 11, 1993
    Assignee: Medtronic, Inc.
    Inventors: David L. Blattenberger, William D. Helgeson, John C. Strohkirch, Bernard Heller
  • Method for lithium anode and electrochemical cell fabrication
    Patent number: 4398346
    Abstract: Method of preparing lithium anodes contacted with organic materials prior to association of the anode with a cathode material wherein the contacted anode is first subjected to a heat treatment. Upon incorporation of the improved anode into an electrochemical battery or cell and association of the heat treated anode with a suitable cathode material, the cell may be discharged under controlled conditions for a short time prior to its usual "burn-in" discharge.
    Type: Grant
    Filed: October 23, 1981
    Date of Patent: August 16, 1983
    Assignee: Medtronic, Inc.
    Inventors: Lloyd J. Underhill, William D. Helgeson