Saft

Universite Dé Lorraine

Saft Groupe Sa

Gerard Barrailh

Philippe Desprez

Sebastien Benjamin

Ali Zenati

Sebastien Laurent

Philippe Laflaquiere

Hubert Razik

Stephane Rael

The invention relates to a method for determining the value of one or more parameters relating to the state of health of at least one accumulator of a battery that is intended to provide electrical energy to an external application, an electronic battery management system implementing this method, and a battery provided with this system. The method comprises the steps consisting in particular in: making a series of measurements of N samples, where N&#x2265;3, of at least the voltage, the current and the cumulative capacitance, at the terminals of said accumulator, when charging or discharging said accumulator; &#x2014;creating a minimization loop by varying a current value of the first parameter of the accumulator from a determined initial value, comprising the following steps: (i) calculating N estimated values of a second parameter linked to the state of charge of the accumulator from the current value of the first parameter and said N samples, respectively (ii) calculating N theoretical values of the second parameter (iii) varying the current value of the first parameter, repeating the preceding calculation steps for each variation of said current value of the first parameter, and determining the value of the first parameter as being the current value of the first parameter that minimizes the difference between the estimated values and the theoretical values of the second parameter.

Method for determining the value of parameters relating to the state of an accumulator of a battery, battery and electronic battery management system

The invention relates to a method and a system for managing the charging of a rechargeable battery by a voltage control or by a current control comprising a plurality (n) of branches connected in series, each branch comprising a plurality (p) of electrochemical elements connected in parallel. Each electrochemical element exhibits a charging profile (PC) comprising at least one plateau zone directly followed by a sloping zone in which the variation of the voltage as a function of the state of charge in the plateau zone is on average at least ten times less fast than the variation of the voltage in the sloping zone.

Method and system for managing the charging of a rechargeable battery comprising several branches of electrochemical elements connected in parallel

A method and system are provided for estimating state of charge of a cell having a positive electrode, for example of a lithium phosphate type, the charge profile of which includes a range of state of charge between about 30 and about 90% in which variation of voltage is 10 times less rapid than for a state of charge higher than 90%. Determination of state of charge for a state of charge greater than 90% is based on either the use of a calibration relationship between cell voltage and state of charge when a current is passing through the cell that is less than a predetermined threshold value and its voltage has stabilized, or on the use of coulometry the result of which is corrected taking into account the accuracy of the current sensor.

Method and system for estimating state of charge of a lithium electrochemical cell having a lithium phosphate type positive electrode

A method for determining a parameter such as the resistance of at least one accumulator of a battery. The method includes the following steps: measuring a first voltage (U1) when the current is substantially equal to a predetermined value; conducting the plurality of voltage and current measurements (Un; In) during a current pulse; calculating a plurality of resistance values (Rn) from the first voltage and from the plurality of voltage and current measurements; determining a resistance value as the average of the calculated resistance values and an associated standard deviation; determining an absolute uncertainty on the value of the resistance as the product of the standard deviation and of a Student coefficient; if the relative uncertainty is less than or equal to a predetermined accuracy threshold, validating the resistance value (R).

Method for determining a parameter of at least one accumulator of a battery

The invention is a monitoring system for a battery having a plurality of accumulators. The system comprises apparatus for measuring the voltage on the terminals of each accumulator; measuring the temperature of the battery; measuring the current flowing through the battery, calculating a voltage difference between a maximum voltage measured on the terminals of one of the accumulators and a minimum voltage measured on the terminals of one of the accumulators; comparing the voltage difference with at least one threshold value depending on the measured temperature and current, and reporting an error if the voltage difference is greater than or equal to the at least one threshold value.

System for monitoring the state of a battery

A method to manage charge and/or discharge of a rechargeable battery comprising at least one electrochemical cell having predetermined maximum continuous charge current (IMR_C) and/or discharge current (IMD_C) allowed, the method comprising the steps of:

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Gradignan, France

Gerard Barrailh