ELECTRIC VEHICLE BATTERY MONITORING SYSTEM

• US 20170254858A1
• Filed: 03/01/2016
• Published: 09/07/2017
• Est. Priority Date: 03/01/2016
• Status: Active Grant

• Current Assignee: Faraday & Future Inc.
• Original Assignee: Faraday & Future Inc.
• Inventors: Weicker, Phillip John, Heinen, Garrett David
• Granted Patent: US 10,436,845 B2
• Time in Patent Office: Days
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Systems and methods for monitoring and controlling a battery are disclosed. Systems can include a battery having an output voltage and an output current when delivering power, a load driven by power delivered from the battery, battery output voltage and current sensing circuits, and processing circuitry coupled to the battery output voltage and current sensing circuits. The processing circuitry may be configured to obtain sensed battery output voltage and current values, and to estimate values for at least three battery state parameters by concurrently fitting the voltage and current values to at least two different equations.

Claims

1. A battery powered apparatus comprising:

a battery comprising one or more electrochemical cells, the battery having an output voltage and an output current when delivering power;

a load driven by power delivered from the battery;

a battery output voltage sensing circuit;

a battery output current sensing circuit; and

processing circuitry coupled to the battery output voltage sensing circuit and the battery output current sensing circuit, the processing circuitry configured to obtain sensed battery output voltage values and sensed battery output current values at defined intervals and to estimate values for at least three battery state parameters at particular times when the battery is delivering power to the load, wherein each of the at least three battery state parameters varies over time as the battery is used to drive the load;

wherein estimating the at least three battery state parameters comprises concurrently fitting sensed battery output voltage values and sensed battery output current values and/or data derived using the sensed battery output voltage values and sensed battery output current values to at least two different equations, wherein each of the at least two different equations are defined at least in part by different subsets of the at least three battery state parameters.

2. The battery powered apparatus of claim 1, wherein one or more of the at least two different equations is a linear equation with a slope and an intercept defined at least in part by one or more of the at least three battery state parameters.

3. The battery powered apparatus of claim 1, wherein estimating comprises storing current estimated values for the at least three battery state parameters, obtaining additional sensed battery output voltage values and sensed battery output current values, and updating the current estimates of the at least three battery state parameters based at least in part on the additional sensed battery output voltage values and sensed battery output current values.

4. The battery powered apparatus of claim 1, wherein the estimation of at least one of the battery state parameters is dependent on the estimated value of at least one other battery state parameter.

5. The battery powered apparatus of claim 1, wherein there are at least six battery state parameters and at least three linear equations.

6. The battery powered apparatus of claim 5, wherein there are six battery state parameters and three linear equations, and the three linear equations comprise:

7. The battery powered apparatus of claim 1, wherein the at least three battery state parameters comprise an open circuit voltage of a battery equivalent circuit.

8. The battery powered apparatus of claim 7, wherein the processing circuitry is further configured to estimate a charge state of the battery based at least in part on the estimated open circuit voltage of the equivalent circuit.

9. A method of operating a battery powered apparatus, the method comprising:

driving a load of the apparatus with a battery;

sensing the output voltage and output current of the battery at defined intervals while driving the load;

using the sensed battery output voltage values and sensed battery output current values to estimate values for at least three battery state parameters at particular times when the battery is driving the load, wherein each of the at least three battery state parameters varies over time as the battery is used to drive the load, wherein the estimating the at least three battery state parameters comprises fitting sensed battery output voltage values and sensed battery output current values and/or data derived from the sensed battery output voltage values and sensed battery output current values to at least two different equations, wherein each of the at least two different equations are defined at least in part by different subsets of the at least three battery state parameters.

10. The method of claim 9, wherein one or more of the at least two different equations is a linear equation with a slope and an intercept defined at least in part by one or more of the at least three battery state parameters.

11. The method of claim 9, wherein estimating comprises storing current estimated values for the at least three battery state parameters, obtaining additional sensed battery output voltage values and sensed battery output current values, and updating the current estimates of the at least three battery state parameters based at least in part on the additional sensed battery output voltage values and sensed battery output current values.

12. The method of claim 9, wherein the estimation of at least one of the battery state parameters is dependent on the estimated value of at least one other battery state parameter.

13. The method of claim 10, wherein there are at least six battery state parameters and at least three linear equations.

14. The method of claim 13, wherein there are six battery state parameters and three linear equations, and the three linear equations comprise:

15. The method of claim 9, wherein the at least three battery state parameters comprise an open circuit voltage of a battery equivalent circuit.

16. The method of claim 15, further comprising estimating a charge state of the battery based on the estimated open circuit voltage of the equivalent circuit.

17. An electric vehicle with a battery monitoring system, the vehicle comprising:

a battery;

a powertrain comprising at least one electric motor driven by the battery;

a battery output voltage sensing circuit;

a battery output current sensing circuit; and

processing circuitry coupled to the battery output voltage sensing circuit and the battery output current sensing circuit, the processing circuitry configured to obtain sensed battery output voltage values and sensed battery output current values at defined intervals and to estimate values for at least three battery state parameters at particular times when the battery is delivering power to the powertrain, wherein each of the at least three battery state parameters varies over time as the battery is used to drive the powertrain, wherein estimating the at least three battery state parameters comprises concurrently fitting sensed battery output voltage values and sensed battery output current values and/or data derived from the sensed battery output voltage values and sensed battery output current values to at least two different equations, wherein each of the at least two different equations are defined at least in part by different subsets of the at least three battery state parameters.

18. The electric vehicle of claim 17, comprising powertrain control circuitry that is configured to receive the estimated battery state parameters and control the powertrain based at least in part on the estimated battery state parameters.

19. The electric vehicle of claim 17, wherein there are six battery state parameters and three linear equations, and the three linear equations comprise:

20. The electric vehicle of claim 17, wherein the battery performance parameters comprise an open circuit voltage of a battery equivalent circuit, and wherein the processing circuitry is further configured to estimate a charge state of the battery pack based at least in part on the estimated open circuit voltage of the equivalent circuit.

21. The electric vehicle of claim 20, wherein the processing circuitry is further configured to calculate a vehicle range estimate and deliver the vehicle range estimate to a user of the vehicle on a display located within the vehicle.

22. The electric vehicle of claim 20, wherein the battery performance parameters further comprise at least one resistance and at least one capacitance of the battery equivalent circuit.

23. The electric vehicle of claim 22, wherein the processing circuitry is further configured to estimate an instantaneous power limit of the battery pack in real time based on the estimated battery state parameters.

24. The electric vehicle of claim 23, further comprising updating a pedal map of the electric vehicle based on the estimated instantaneous power limit.

25. The electric vehicle of claim 17, wherein the battery performance parameters comprise a series resistance of a battery equivalent circuit.

26. The electric vehicle of claim 25, wherein the processing circuitry is further configured to compare the series resistance to a predetermined threshold and notify a user of the vehicle that battery maintenance is necessary when the series resistance exceeds the predetermined threshold.