The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 14, 1976
Filed:
Oct. 20, 1975
John J Winter, Atlantic Highlands, NJ (US);
James T Breslin, Asbury Park, NJ (US);
Raymond L Ross, Ocean, NJ (US);
Frederick Rothwarf, Toms River, NJ (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
A method for determining the state-of-charge for zinc mercuric oxide type primary cells. I-V curves of the cells are plotted and the nearly constant slopes of these I-V curves above 75mA are measured graphically. These slopes are used to define effective differential DC resistance values (.DELTA.V/.DELTA.I).sub.75mA which have a linear relationship to charge expended, Q(A-h), which is graphically produced by plotting (.DELTA.V/.DELTA.I).sub.75mA versus Q(A-h). This relationship is used as a basis for a state-of-charge indicator to determine the remaining charge to about 12%. One can also subtract the internal resistance of the cell (measured with an a-c bridge technique) from (.DELTA.V/.DELTA.I).sub.75mA and obtain a new parameter, R.sub.p, which is related to the polarization resistance of the cell. The maximum uncertainty can be reduced to less than 10% if the linear curve is produced by plotting polarization resistance R.sub.p of the cell versus the charge expended Q(A-h). More significantly, the polarization based state-of-charge graph is linear out to 100% of discharge and is applicable to cells discharged at abnormally high current.