EP0714033A2
Expired / Lapsed
EP
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Method and apparatus for predicting the remaining capacity and reserve time of a battery on discharge
Assignee: AT&T Inc
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Filing: 1995-11-14
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Granted: —
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Expires: 2015-11-14
Abstract
Abstract A highly accurate apparatus and method of predicting remaining capacity Q and reserve time t of a discharging battery to a selected end voltage is determined by an arrangement considering the open circuit voltage, battery voltage, battery temperature and its internal resistance. The remaining battery capacity Q is determined from the difference between the battery full charge open circuit voltage Eoc and the voltage loss due to the internal resistance of the battery IRint and the battery voltage on discharge divided by the battery temperature T, which is the temperature-corrected battery overvoltage.
Inventors
- 👤 Trung V. Nguyen
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 15:30
CPC Classifications
G; G01; G01R; G01R31/00; G01R31/36; G01R31/378; G01R31/379; G01R31/367; G01R31/382; G01R31/3842; G01R31/389; G01R31/392; Y; Y10; Y10S; Y10S320/00; Y10S320/18; Y10S320/21
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
117 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge, comprising the steps of: determining an open circuit voltage of the battery; CHARACTERIZED BY: measuring a discharge current and discharge voltage of the battery in the process of discharge; measuring a temperature of the battery in the process of discharge; determining a remaining reserve capacity of the battery in a process of discharge by deriving a value for battery overvoltage based on determined and measured battery parameters including the open circuit voltage, the discharge current, the discharge voltage and the temperature of the battery; using the reserve capacity to determine the reserve time remaining to a final end voltage.
Claim 2
Dependent Claim
41 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge as claimed in claim 1: wherein the battery overvoltage definition is expressed as η= E oc -IR int - V battery T .
Claim 3
Dependent Claim
54 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge as claimed in claim 2 wherein the step of determining a remaining reserve capacity of the battery in a process of discharge includes expressing a ratio of remaining capacity to maximum capacity as an exponential function.
Claim 4
Dependent Claim
60 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge as claimed in claim 3 wherein the exponential expression is given the form Q Q max = e (a+bη c +dη e ) where Q max , a, b, c, d, and e are predetermined parameters determined by the battery embodiment;
Claim 5
Dependent Claim
61 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge as claimed in claim 1 wherein the step of using the reserve capacity to determine the reserve time remaining to a final end voltage includes a step of measuring a discharge current and a ratio of the reserve capacity to the discharge current.
Claim 6
Independent Claim
82 words
A method of predicting the reserve time of a discharging battery with a known maximum capacity, comprising the steps of: determining temperature dependence of a battery overvoltage of the discharging battery; reducing the temperature dependence of a battery overvoltage to a ratio of battery capacity of the discharging battery to its maximum capacity; and measuring the discharge current and combining it with the battery capacity of the discharging battery to determine a reserve time to discharge the battery to an end voltage.
Claim 7
Dependent Claim
64 words
A method of predicting the reserve time of a discharging battery with a known maximum capacity as claimed in claim 5, wherein the step of reducing the temperature dependence of a battery overvoltage to a ratio of battery capacity of the discharging battery to its maximum capacity includes evaluation of the equation, Q Q max = e (a+bη c +dη e ) .
Claim 8
Dependent Claim
44 words
A method of predicting the reserve time of a discharging battery with a known maximum capacity as claimed in claim 5, wherein the step of determining temperature dependence includes evaluation of the equation, η = E oc -IR int - V battery T .
Claim 9
Independent Claim
159 words
A method of predicting the remaining capacity and reserve time of a discharged battery, characterized by the steps of: measuring a discharge voltage of the battery, measuring the discharge current of the battery and measuring the temperature of the battery to determine a temperature corrected battery overvoltage η of the form: η = E oc - IR int - V battery T where E oc is the battery open circuit voltage, I is the discharge current of the battery, R int is the internal resistance of the battery, V battery is the battery voltage during discharge and T is the battery temperature; determining the value Q for the remaining capacity using a characteristic curve of the form: Q Q max = e (a+bη c +dη e ) and using predetermined values for the parameters Q max , a, b, c, d, and e; and determining the reserve time according to the relation: Reserve Time = Q I .
Claim 10
Independent Claim
154 words
A method of predicting the remaining capacity and reserve time of a discharging battery, characterized by the steps of: measuring discharge data of the battery at selected constant discharge currents to derive a battery capacity versus temperature corrected battery overvoltage characteristic curve according to the following relation: Q Q max = e (a+bη c +dη e ) where: η = E oc - IR int - V battery T Q max is maximum theoretical capacity of the battery, E oc is the battery open circuit voltage, I is the discharge current of the battery, R int is the internal resistance of the battery, V battery is the battery voltage during discharge, T is the battery temperature, and a, b, c, d, and e are curve fitting parameters related to the design of the battery; and solving for the remaining capacity value of reserve time t according to the relation; t = Q I
Claim 11
Dependent Claim
176 words
Apparatus for predicting a reserve capacity and remaining reserve time of a battery in discharge; comprising: CHARACTERIZED BY: voltage sensing circuitry connected to a terminal voltage of the battery; current sensing circuitry connected for sensing a load current of the battery; a temperature sensing device positioned for sensing a temperature of the battery; a battery monitoring circuit connected to receive input from the voltage sensing circuitry, the current sensing circuitry and the temperature sensing device; and including a reserve time prediction sub-unit having: a stored program controller for controlling and receiving input from the voltage sensing circuitry, the current sensing circuitry and the temperature sensing device and determining if the battery is discharging, memory associated with the stored program controller and including battery characteristic data including E oc ,R int ,Q max , and battery parameters; the stored program controller including instructions for determining a value of: Q Q max = e (a+bη c +dη e ) and calculating a predicted reserve time t using the equation by the relation: t = Q I .
Claim 12
Independent Claim
118 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge, comprising the steps of: determining an open circuit voltage of the battery; CHARACTERIZED BY: measuring a discharge current and discharge voltage of the battery in the process of discharge; using a temperature of the battery environment in the process of discharge; determining a remaining reserve capacity of the battery in a process of discharge by deriving a value for battery overvoltage based on determined and measured battery parameters including the open circuit voltage, the discharge current, the discharge voltage and the temperature of the battery; using the reserve capacity to determine the reserve time remaining to a final end voltage.
Claim 13
Dependent Claim
74 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge as claimed in claim 11: wherein the temperature related battery overvoltage definition is expressed as ηT = E oc - IR int - V battery where T is battery related temperature, E oc is the open circuit voltage of the battery, IR int is an internal battery voltage, and V battery is the discharge battery voltage.
Claim 14
Dependent Claim
73 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge as claimed in claim 12 wherein the step of determining a remaining reserve capacity of the battery in a process of discharge includes expressing a ratio of remaining capacity to maximum capacity as a function of η where Q Q max =f η where Q max , is a predetermined parameter of the battery embodiment.
Claim 15
Dependent Claim
41 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge as claimed in claim 13 wherein the expression is given the form Q Q max = e (a+bη c +dη e )
Claim 16
Independent Claim
99 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge, comprising the steps of: determining an open circuit voltage of the battery; CHARACTERIZED BY: measuring a discharge current and discharge voltage of the battery in the process of discharge; determining a remaining reserve capacity of the battery in a process of discharge by deriving a value for battery overvoltage based on determined and measured battery parameters including the open circuit voltage, the discharge current, and the discharge voltage of the battery; using the reserve capacity to determine the reserve time remaining
Claim 17
Dependent Claim
36 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge as claimed in claim 15: including further measuring a temperature of the battery in the process of discharge.
Claim 18
Dependent Claim
38 words
A method of predicting a remaining capacity and reserve time of a battery in a process of discharge as claimed in claim 15: including further considering that the battery is operating at ambient temperature and utilizing that temperature.
References Cited (Backward Citations)
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