Managing the charging of a battery

Abstract

The invention concerns a method for managing the charging of an Li-ion battery on the basis of at least one parameter chosen from the group consisting of the deterioration of the battery and cell imbalance, comprising the following steps of receiving a signal determining the end-of-charge voltage value of said battery, of generating a control signal controlling the charging of said battery, and of transmitting the control signal to a charger, the control signal being generated such that the battery is charged on the basis of the end-of-charge voltage value determined in step a), said end-of-charge voltage value being increased on the basis of the state of deterioration of said Li-ion battery until a limit value is reached, in order to ensure a constant minimal level of required energy in said Li-ion battery, for a predetermined reference temperature.

1 . A method for managing the charging of a Li-ion battery as a function of at least one parameter chosen from the group comprising the ageing of the battery and the cell unbalance representing the difference between the state of charge of the cell exhibiting the highest charge and the state of charge of the cell exhibiting the lowest charge, comprising the following steps of:
 a) determining an end-of-charge voltage value of said battery,   b) generating a control signal controlling the charging of said battery and of transmitting the control signal to a charger, the control signal being generated such that the battery is charged as a function of the end of charge voltage value determined in step a), said end-of-charge voltage value being increased as a function of the state of ageing of said Li-ion battery until a limit value is reached in order to ensure a constant minimum required energy level in said Li-ion battery, for a predetermined reference temperature.   
     
     
         2 . The method as claimed in  claim 1 , comprising, prior to step a), a step of generating and processing a signal of evaluation of the state of ageing of the battery. 
     
     
         3 . The method as claimed in  claim 1 , comprising, after step b), a step of generating and processing an end-of-charge signal when the maximum cell voltage value is greater than or equal to the end-of-charge voltage value and when the authorized charging power in the battery is less than or equal to the maximum authorized end-of-charge power. 
     
     
         4 . The method as claimed in  claim 1 , comprising, in step b), a step c) of generating and processing a modulation signal of said end-of-charge voltage increased as a function of the cell unbalance. 
     
     
         5 . The method as claimed in  claim 4 , characterized in that step a) of determining the end-of-charge voltage value consists of determining the cut-off voltage for the end-of-charge on the maximum cell voltage and the cut-off voltage for the end-of-charge on the minimum cell voltage as a function of the state of ageing of the battery. 
     
     
         6 . The method as claimed in  claim 4 , characterized in that it comprises, after step c), a step of receiving and processing an end-of-charge signal when the authorized charging power in the battery is less than or equal to the maximum authorized end-of-charge power and when the maximum cell voltage value is greater than or equal to the end-of-charge cut-off voltage on the maximum cell voltage or when the value of the minimum cell voltage is greater than or equal to the end-of-charge cut-off voltage on the minimum cell voltage. 
     
     
         7 . A device for managing the charging of a Li-ion battery as a function of at least one parameter chosen from the group consisting of the ageing of the battery and the cell unbalance representing the difference between the state of charge of the cell exhibiting the highest charge and the state of charge of the cell exhibiting the lowest charge, comprising,
 1) means of determining an end-of-charge voltage value of said battery,   2) processing means arranged to generate a control signal for controlling the charging of said battery,   3) means of transmitting the control signal to a charger,   characterized in that the processing means are arranged so that the control signal is generated in such a way that the charging of the battery is carried out as a function of the determined end-of-charge voltage value, said end-of-charge voltage value being increased as a function of the increasing state of ageing of said Li-ion battery up to a limit value in order to provide a constant minimum required energy level in said Li-ion battery, for a predetermined reference temperature.   
     
     
         8 . The device as claimed in  claim 7 , characterized in that it furthermore comprises means of generating and processing a signal of evaluation of the state of ageing of the battery and the means of determining the end of charge voltage value are arranged to determine the cut-off voltage for the end-of-charge on the maximum cell voltage and the cut-off voltage for the end-of-charge on the minimum cell voltage as a function of the state of ageing of the battery. 
     
     
         9 . A lithium-ion battery assembly comprising a lithium-ion battery and a device for managing charging as claimed in  claim 7 . 
     
     
         10 . A motor vehicle incorporating a lithium-ion battery assembly as claimed in  claim 9 .