Method and apparatus for detecting failed batteries
First Claim
1. A method of identifying a failed battery, wherein the battery includes two portions connected in series, each portion including a plurality of serially connected cells, the method comprising the steps of:
- receiving a first signal representing a voltage measured across the first portion while the battery receives a float voltage while connected to an electric charging circuit;
receiving a second signal representing a voltage measured across the second portion while the battery receives the float voltage while connected to the electric charging circuit;
receiving a third signal representing a voltage measured across a combination of the two portions while the battery receives the float voltage while connected to the electric charging circuit;
determining whether the battery has failed based upon a ratio comparative analysis which is a function of the voltage measured across the first portion, the voltage measured across the second portion, and the voltage measured across a combination of the two portions.
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Accused Products
Abstract
A technique for detecting failed batteries while the battery is attached to one or more electronic devices and is receiving a float charge is disclosed. The float voltage minimizes the normal voltage differences between battery cells. The technique employs a ratio comparative analysis of cell voltages of a battery provided across the terminals of the battery. Application of the ratio comparative analysis in assessing the condition of a battery assumes an equal voltage drop across each battery cell such that the cells are modeled as a series of resisters with respect to the float voltage. Such equal voltage drop enables a comparative ratio analysis of the voltage across each of the two portions of the battery'"'"'s cell stack to the voltage across the entire battery. The comparative ratio analysis determines a voltage threshold that identifies whether a battery has a shorted or open cell.
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Citations
28 Claims
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1. A method of identifying a failed battery, wherein the battery includes two portions connected in series, each portion including a plurality of serially connected cells, the method comprising the steps of:
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receiving a first signal representing a voltage measured across the first portion while the battery receives a float voltage while connected to an electric charging circuit; receiving a second signal representing a voltage measured across the second portion while the battery receives the float voltage while connected to the electric charging circuit; receiving a third signal representing a voltage measured across a combination of the two portions while the battery receives the float voltage while connected to the electric charging circuit; determining whether the battery has failed based upon a ratio comparative analysis which is a function of the voltage measured across the first portion, the voltage measured across the second portion, and the voltage measured across a combination of the two portions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A battery testing system for identifying a failed battery having at least two portions connected in series, the system comprising:
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a battery charger which is removeably coupled to the battery for providing a float voltage across the battery; a voltage measuring device for measuring voltages across the battery and providing a first signal, a second signal and a third signal, wherein the first signal represents a voltage measured across the first portion, the second signal represents a voltage measured across the second portion, and the third signal represents a voltage measured across a combination of the two portions; and a battery tester determiner coupled to the voltage measuring device for receiving the first signal, the second signal and the third signal; and
determining whether the battery has failed based upon a ratio comparative analysis which is a function of the first signal, the second signal and the third signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method for calculating a threshold value which is used to determine whether a battery having two serially connected portions is defective, the method comprising the steps of:
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determining a voltage ratio for a first battery having two serially connected portions with a shorted cell in either portion; determining a voltage ratio for a second battery having two serially connected portions with an open cell in either portion; determining a lesser value between the voltage ratio for the first battery and the voltage ratio for the second battery; and setting the threshold value to a value proximally less than the lesser value. - View Dependent Claims (22, 23)
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24. A computer program product which is readable by a machine, the product tangibly embodying a set of executable programming instructions which perform steps for detecting whether a battery having at least two portions is defective, the steps comprising:
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receiving a first signal which represents a voltage measured across a first portion of the battery; receiving a second signal which represents a voltage measured across a second portion of the battery; receiving a third signal which represents a voltage measured across a combination of the first and second portions; and determining whether the battery is defective based upon a ratio comparative analysis which is a function of the voltage measured across the first portion, the voltage measured across the second portion, and the voltage measured across the combination of the first and second portions. - View Dependent Claims (25, 26, 27, 28)
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Specification