Method for calculating the parameters of the power battery of an electric motor vehicle

• US 6,788,069 B2
• Filed: 08/05/2002
• Issued: 09/07/2004
• Est. Priority Date: 08/10/2001
• Status: Expired due to Fees

• Current Assignee: Peugeot Citroen Automobiles SA (Stellantis NV)
• Original Assignee: Peugeot Citroen Automobiles SA (Stellantis NV)
• Inventors: Vacher, Cécile
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): Nguyen, Vincent Q.
• Application Number:
  US10/212,997
• Publication Number:
  US 20030034780A1
• Time in Patent Office: 764 Days
• Field of Search: 180/65.8, 180/65.3, 180/302, 320/162, 320/134, 324/426, 324/427, 324/430, 324/431, 324/433, 324/435, 324/444, 702/63-65, 702/183, 702/184, 702/FOR.103, 702/FOR.105, 340/636.1, 340/636.11, 340/636.13, 340/455, 340/438, 340/636.12, 123/2
• US Class Current: 324/430
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• 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

The invention relates to a method for determining at least one operating parameter of the power battery of a vehicle having an electric traction motor. The battery parameter includes at least one of the following parameters: charging capacity, discharge power, state of overcharge or state of total discharge. The power battery'"'"'s internal resistance and the intensity of the current supplied or received are determined in order to calculate the parameter(s). This internal resistance is calculated, for example, using a low voltage auxiliary battery.

Claims

1. A method for monitoring a power battery of a vehicle having an electric traction motor, comprising the steps of:

measuring an internal resistance of the power battery;

measuring a current supplied by or received from the power battery; and

determining at least one operating parameter of the power battery selected from a group consisting of charging capacity and discharge power state, responsive to the measured internal resistance and current;

wherein the step of determining the at least one parameter uses the following equation;

$P=U<br><br>\frac{E\pm <br><br>U}{R}$

wherein U is a voltage provided by the power battery, E is an electromotive force or back electromotive force, R is an internal resistance, the + sign indicates battery charge and the −

sign indicates battery discharge.

5. A method according to claim 1, 2, 3 or 4, further including the step of measuring a state of charge (SOC) of the battery to identify a preset value to use as an electromotive force or back electromotive force of the battery.

6. A method according to claim 5, further including the step of measuring a temperature of the battery to identify a preset value to use as the electromotive force or back electromotive force of the battery.

10. A method according to claim 1, further including the step of determining a state of aging of the battery responsive to the internal resistance of the battery.

11. A method according to claim 1 or claim 4, wherein the vehicle includes an ignition circuit and the step of measuring the internal resistance is carried out when the ignition circult is switched off.

12. A method according to claim 11, wherein the step of measuring the internal resistance is carried out automatically at intervals.

13. A method according to claim 1, 2, 3, or 4, wherein at least one of the steps of measuring the internal resistance of the power battery and measuring the current supplied by or received from the battery is triggered by a signal outside the vehicle and the step of determining the at least one operating parameter is performed outside the vehicle.

14. A method according to claim 1, 2, 3 or 4 wherein the power battery is for a hybrid type vehicle comprising, an internal combustion type engine for propulsion and an alternator, coupled to the internal combustion engine, further including the step of charging the battery from a current generated by the alternator.

2. A method for monitoring a power battery of a vehicle having an electric traction motor, comprising the steps of:

measuring an internal resistance of the power battery;

measuring a current supplied by or received from the power battery; and

determining a state of overcharge of the power battery, which has a first state if the battery provides a voltage greater than a battery terminal high voltage threshold U_max and has a second state otherwise, wherein the terminal high voltage threhsold U_max is determined from the following formula;

3. A method for monitoring a power battery of a vehicle having an electric traction motor, comprising the steps of:

measuring an internal resistance of the power battery;

measuring a current supplied by or received from the power battery;

determining at least one operating parameter of the power battery selected from a group consisting of charging capacity, discharge power, state of overcharge and state of total discharge responsive to the measured internal resistance and current; and

applying a corrective expression, which depends on a state of polarization of the battery, to correct each measured value of the battery'"'"'s internal resistance.

7. A method according to claim 3, further including the steps of:

measuring a temperature of the battery; and

calculating the corrective expression responsive to the temperature.

8. A method according to claim 3, further including the step of calculating the corrective expression responsive to the at least one parameter to be calculated.

9. A method according to claim 8, further including the step of calculating the corrective expression responsive to a time at which the at least one parameter must be calculated.

4. A method for monitoring a power battery of a vehicle havin an electric traction motor, comprising the steps of:

measuring an internal resistance of the power battery including the step of connecting an auxiliary low voltage battery to the power battery via a two-way DC/DC type converter;

measuring a current supplied by or received from the power battery; and

determining at least one operating parameter of the power battery, selected from a group consisting of charging capacity and discharge power state responsive to the measured internal resistance and current.