Method and apparatus for charging and testing batteries
First Claim
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1. A method of charging and testing a rechargeable battery which comprises the steps of:
- (a) measuring the open circuit voltage of said battery and estimating the number of cells possible for the measured open circuit voltage;
(b) supplying a controllably varying charging current or voltage to the battery for a predetermined period of time while measuring the response voltage or current produced at or through the battery terminals and testing said battery for the evolution of gas;
(c) charging said battery automatically with a charge input at any charge rate until the battery charge voltage equals the estimated number of cells of the battery multiplied by a predetermined voltage which is characteristic of the battery;
(d) repeating steps (a), (b), and (c) until step (b) indicates the evolution of gas;
(e) determining the current ("Igas-up") and voltage ("Vgas-up") at which said battery evolves gas in the increasing current direction, and the current ("Igas-down") and voltage ("Vgas-down") at which the battery stops evolving gas in the decreasing current direction;
(f) determining the true number of cells in said battery from said Vgas-up and/or said Vgas-down;
(g) determining the state of charge using the true number of cells determined in step (f), the open circuit voltage measured in step (a) and the charge input to said battery by the apparatus;
(h) determining the capacity of said battery from said Igas-up when said Igas-down is lower than or equal to a predetermined value, or from the difference in said Igas-up and Igas-down when said Igas-down is greater than or equal to a predetermined value;
(i) determining defect conditions from said open circuit voltage; and
(j) determining defect conditions from the current voltage characteristics generated in step (b).
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Abstract
An apparatus for charging and testing a rechargeable battery is adapted to determine certain conditions, including defects and characteristics, of the battery. The apparatus detects defects caused by sulfated cells, short circuited cells, and mismatched cells, and determines battery voltage, capacity and charge acceptance capability.
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21 Claims
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1. A method of charging and testing a rechargeable battery which comprises the steps of:
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(a) measuring the open circuit voltage of said battery and estimating the number of cells possible for the measured open circuit voltage; (b) supplying a controllably varying charging current or voltage to the battery for a predetermined period of time while measuring the response voltage or current produced at or through the battery terminals and testing said battery for the evolution of gas; (c) charging said battery automatically with a charge input at any charge rate until the battery charge voltage equals the estimated number of cells of the battery multiplied by a predetermined voltage which is characteristic of the battery; (d) repeating steps (a), (b), and (c) until step (b) indicates the evolution of gas; (e) determining the current ("Igas-up") and voltage ("Vgas-up") at which said battery evolves gas in the increasing current direction, and the current ("Igas-down") and voltage ("Vgas-down") at which the battery stops evolving gas in the decreasing current direction; (f) determining the true number of cells in said battery from said Vgas-up and/or said Vgas-down; (g) determining the state of charge using the true number of cells determined in step (f), the open circuit voltage measured in step (a) and the charge input to said battery by the apparatus; (h) determining the capacity of said battery from said Igas-up when said Igas-down is lower than or equal to a predetermined value, or from the difference in said Igas-up and Igas-down when said Igas-down is greater than or equal to a predetermined value; (i) determining defect conditions from said open circuit voltage; and (j) determining defect conditions from the current voltage characteristics generated in step (b). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification