ASSESSING THE QUANTITY OF ENERGY IN A MOTOR VEHICLE BATTERY

• US 20160377684A1
• Filed: 12/02/2014
• Published: 12/29/2016
• Est. Priority Date: 12/12/2013
• Status: Abandoned Application

• Current Assignee: Renault Sas (Renault)
• Original Assignee: Renault Sas (Renault)
• Inventors: LALLICH, Sylvain, LEIRENS, Sylvain
• Application Number:
  US15/102,382
• Publication Number:
  US 20160377684A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A method for evaluating a quantity of energy at constant power of a battery includes determining a value of a capacity parameter for the battery, constructing a table of values for a parameter of voltage across terminals of the battery as a function of a value of a current parameter, for N values of a state of charge parameter, determining a value of an internal resistance parameter for the battery, providing a table of values of an open-circuit voltage parameter, estimating a value of the state of charge parameter at an initial time, and estimating a quantity of energy parameter between a final and initial states of charge using a function whose variable is the state of charge parameter and whose parameters are said value of the capacity parameter for the battery, said value of the internal resistance parameter, and said value of the open-circuit voltage parameter.

Claims

1-10. -10. (canceled)

11. A method for evaluating a quantity of energy at constant power of a battery of an automobile vehicle, said quantity of energy corresponding to a extractible quantity of energy or to a quantity of energy to be accumulated, said method comprising:

(a) determining a value of a capacity parameter for the battery;

(b) constructing, during a charge phase of the battery, a table of values for a parameter of voltage across terminals of the battery as a function of a value of a current parameter for N values of a state of charge parameter;

(c) determining a value of an internal resistance parameter for the battery as a function of a state of charge parameter for said battery based on the table constructed at the step (b);

(d) providing a table of values of an open-circuit voltage parameter for the battery as a function of the state of charge parameter for the battery;

(e) estimating a value of the state of charge parameter for the battery at an initial time, corresponding to an initial state of charge of the battery; and

(f) estimating by calculation a value of a quantity of energy parameter between a final state of charge and said initial state of charge using a function whose variable is the state of charge parameter and whose parameters are said value of the capacity parameter for the battery, said value of the internal resistance parameter and said value of the open-circuit voltage parameter.

12. The method as claimed in claim 11, in which the function used in the step (f) for estimating the quantity of energy is written:

f(z)=Uoc(z)+√

{square root over (Δ

(z))} 

 

(2),

in which;

Δ

(z) is a term taking into account the energy losses, being a function of the value of the state of charge parameter,

Uoc(z) represents the open-circuit voltage parameter as a function of the value of the state of charge parameter,

and the value of the quantity of energy parameter is obtained by integration of said function between the value of the state of charge parameter in the initial state and the value of the state of charge parameter in the final state, said value of the final state of charge parameter being the solution of the equation;

13. The method as claimed in claim 12, in which the function is approximated by a polynomial of order n less than or equal to N-1 and said value of quantity of energy parameter is expressed by:

14. The method as claimed in claim 11, in which the steps (a) and (b) are iterated over a lifetime of the battery, independently of each other and of the steps (e) and (f) of said method.

17. The method as claimed in claim 11, further comprising, after the step (f), the following additional step:

(g) determining a new value of the initial state of charge parameter using the value of quantity of energy parameter estimated at the step (f).

18. The method as claimed in claim 17, in which the steps (e) to (g) may be implemented for a first value of power parameter, then the step (f) may be implemented for a second value of power parameter using the value of the initial state of charge parameter determined at the step (g).

15. The method as claimed in claim H, in which the step (e) for estimating the value of the initial state of charge parameter comprises, at the initial time:

(i) measuring the value of the parameter of voltage across the terminals of the battery and the value of the parameter of current flowing in the battery when said value of the current parameter is stable for a predetermined period of time during a discharge phase of the battery, and

(ii) deducing from the measuring the value of the initial state of charge parameter based on the table constructed at the step (b).

16. The method as claimed in claim 15, in which the step e comprises the following additional steps:

(iii) estimating a second value of the initial state of charge parameter by another prediction method,

(iv) comparing the first value of the initial state of charge parameter determined at the step (ii) with the second value of the initial state of charge parameter determined at the step (iii), and

(v) using the value of the initial state of charge parameter determined at the step (ii) if the difference from the comparing is less than a predetermined value, otherwise, using the second value of the initial state of charge parameter determined at the step (iii).

19. A device for evaluating a quantity of energy of a battery of an automobile vehicle at constant power, said quantity of energy corresponding to an extractible quantity of energy or to a quantity of energy to be accumulated, comprising:

receiving means to receive various values of parameters including a value of a parameter of voltage across terminals of the battery, a value of a current parameter, and potentially a value of a time parameter;

means for storing the values received by the receiving means and storing a table of values of a parameter of voltage across the terminals of the battery as a function of the value of a current parameter for N values of a state of charge parameter of said battery and a table of values of an open-circuit voltage parameter for the battery as a function of the state of charge parameter for the battery; and

processing means for;

determining a value of a capacity parameter for the battery,

constructing a table of values of a parameter of voltage across the terminals of the battery as a function of the value of a current parameter for N values of a state of charge parameter for said battery,

determining a value of an internal resistance parameter for the battery as a function of said state of charge parameter for said battery using the table constructed,

estimating a value of the state of charge parameter for the battery at an initial time, corresponding to an initial state of charge of the battery, as a function of the table stored in the storage means, and

estimating by calculation a value of quantity of energy parameter between a final state of charge and said initial state of charge using a function whose variable is the state of charge parameter and whose parameters are said value of the capacity parameter for the battery, said value of the internal resistance parameter and said value of the open-circuit voltage.

20. An automobile vehicle comprising:

a battery; and

the device as claimed in claim 19 for evaluating a quantity of energy for said battery at constant power.