ELECTRIC VEHICLE BATTERY CHARGE AND DISCHARGE MANAGEMENT

• US 20170120772A1
• Filed: 10/28/2016
• Published: 05/04/2017
• Est. Priority Date: 10/30/2015
• Status: Active Grant

• Current Assignee: Faraday & Future Inc.
• Original Assignee: Faraday & Future Inc.
• Inventors: Paryani, Anil, Alser, John, Chidester, Douglas D., Weicker, Phillip John
• Granted Patent: US 10,259,337 B2
• Time in Patent Office: Days
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 53/67 Controlling two or more charging stations
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations

Abstract

An adaptive multi-string battery for an electric vehicle is disclosed herein. The battery strings can adaptively be connected to the power bus bars based on the output voltage to be discharged with load. During operation of the vehicle, the voltage, current, and estimate charge can be constantly monitored to change the connected status of the battery strings to the power buses to allow connecting or disconnecting of the battery strings adaptively.

Claims

1. An electric vehicle comprising:

a motor coupled to one or more wheels of the electric vehicle;

an inverter coupled to the motor;

at least a first power bus coupled to the inverter; and

a first battery string having an output that is coupled to the first power bus through a first switch,

at least a second battery string different from the first battery string having an output that is coupled to the first power bus through a second switch different from the first switch;

control circuitry coupled to at least the first switch and the second switch, the control circuitry configured to selectively and independently control the open or closed state of the first switch and the second switch, thereby selectively and independently connecting the output of the first battery string and the output of the second battery string to the first power bus.

2. The electric vehicle of claim 1, comprising a first current sensor in series with the first switch, and a second current sensor in series with the second switch.

3. The electric vehicle of claim 1, wherein the first battery string and the second battery string have outputs coupled to a second power bus through respective third and fourth switches.

4. The electric vehicle of claim 3, wherein the control circuitry is configured to control the open or closed state of the third and fourth switches.

5. The electric vehicle of claim 1, wherein the first battery string and the second battery string each comprise a plurality of modules of cells connected in parallel and wherein each of the plurality of modules of cells comprise a plurality of cells connected in series.

6. The electric vehicle of claim 1, wherein the control circuitry is configured to measure the voltage across the first battery string when the first switch is open, and to measure the voltage across the second battery string when the second switch is open.

7. The electric vehicle of claim 6, wherein the control circuitry is configured to measure the voltage on the first power bus when at least one of the first and second switches are closed.

8. The electric vehicle of claim 6, wherein the control circuitry is configured to measure the output current of the first battery string when the first switch is closed and the output current of the second battery string when the second switch is closed.

9. A method of powering an electric vehicle, the electric vehicle comprising at least one electric motor driven with at least one power bus, the method comprising:

determining a plurality of separate output voltages for a corresponding plurality of separate battery strings of the electric vehicle; and

connecting or disconnecting different ones of the plurality of battery string to the power bus based at least in part on the determined plurality of separate output voltages.

10. The method of claim 9, further comprising:

identifying the battery string having the highest voltage;

connecting the identified highest voltage battery string to the power bus; and

connecting another one of the plurality of battery strings if the voltage of the another battery string is within a threshold voltage difference below the highest battery string voltage.

11. The method of claim 10, comprising connecting all of the plurality of battery strings to the power bus that are within the threshold voltage difference below the highest battery string voltage.

12. The method of claim 11, comprising not connecting any of the plurality of battery strings that are not within the threshold voltage difference below the highest battery string voltage.

13. The method of claim 12, further comprising:

subsequent to connecting all of the plurality of battery strings to the power bus that are within the threshold voltage difference below the highest battery string voltage, delivering power to an electric motor of the electric vehicle from the battery strings connected to the power bus.

14. A method of powering an electric vehicle comprising:

initially connecting some but not all of a plurality of battery strings of the electric vehicle to a power bus;

loading the power bus with an electric motor of the electric vehicle;

while the power bus is loaded with the electric motor, measuring the voltage of the power bus; and

connecting an unconnected one of the plurality of battery strings to the power bus if the voltage of the unconnected one of the plurality of battery strings is within a threshold voltage below the measured voltage of the power bus.

15. The method of claim 14, further comprising measuring at least one discharge current for at least one connected one of the plurality of battery strings.

16. The method of claim 15, further comprising:

disconnecting a connected one of the plurality of battery strings if the discharge current of the connected one of the plurality of battery strings is below a threshold.

17. The method of claim 15, further comprising:

storing a measured initial voltage of at least one of the plurality of battery strings;

estimating a state of charge of at least one of the plurality of battery strings based in at least part on the stored initial voltage and the measured discharge current of the at least one of the plurality of battery strings; and

disconnecting the at least one of the plurality of battery strings if the estimated state of charge of the at least one of the plurality of battery strings is below a threshold.

18. A method of charging an electric vehicle, the electric vehicle comprising at least one electric motor driven with at least one power bus, the method comprising:

determining a plurality of separate output voltages for a corresponding plurality of separate battery strings of the electric vehicle;

identifying the battery string having the lowest voltage;

connecting the identified lowest voltage battery string to the power bus;

connecting another one of the plurality of battery strings if the voltage of the another battery string is within a threshold voltage difference above the lowest battery string voltage; and

connecting a charging power source to the power bus.

19. The method of claim 18, comprising connecting all of the plurality of battery strings to the power bus that are within the threshold voltage difference above the lowest battery string voltage.