Power prediction for reconfigurable series-connected battery with mixed battery chemistry

Patent metadata

Field	Value
Publication number	US-11485239-B2
Application number	US-201916429814-A
Country	US
Kind code	B2
Filing date	Jun 3, 2019
Priority date	Jun 3, 2019
Publication date	Nov 1, 2022
Grant date	Nov 1, 2022

Abstract

Powerflow of a rechargeable energy storage system (RESS) is managed according to a method. The RESS has series-connected first and second battery elements with different characteristics. Each element, e.g., a pack, has a corresponding maximum or minimum voltage or current limit. Currents are predicted for each of the first and second battery elements via a controller using a corresponding voltage limit. A requested operating mode of the RESS is used to select a current for the elements. A voltage across the elements is predicted using the selected current and a corresponding battery state space model. The method predicts a total power capability of the RESS over a prediction horizon using the selected current to generate predicted power capability values. The requested operating mode is controlled over the horizon using the power capability values. A powertrain system includes the RESS, an inverter, an electric machine, and the controller.

First claim

What is claimed is:

1. A method for managing powerflow of a multi-pack rechargeable energy storage system (RESS) of a powertrain system having a power inverter module (PIM) and a rotary electric machine connected to the PIM, wherein the rotary electric machine includes an output member connected to a load, the RESS having series-connected (S-connected) first and second battery packs with different characteristics, wherein each of the first battery pack and the second battery pack have a corresponding maximum voltage or current limit, the method comprising:
predicting a corresponding first and second pack current for the first battery pack and the second battery pack, respectively, via a controller of the powertrain system using the corresponding maximum voltage limit;
receiving, via the controller, a requested operating mode of the RESS;
selecting the first or second pack current as a selected current based on the requested operating mode;
predicting a pack voltage across each of the first battery pack and the second battery pack using the selected current and corresponding battery state models;
predicting a total power capability of the RESS over a predetermined prediction horizon using the selected current to thereby generate a plurality of predicted power capability values; and
controlling the requested operating mode over the predetermined prediction horizon, via the controller, using the plurality of predicted power capability values.

2. The method of claim 1 , wherein selecting the first or second pack current includes selecting a minimum of the first or second pack current when the requested operating mode is a charging mode.

3. The method of claim 1 , wherein selecting the first or second pack current includes selecting a minimum of the first or second pack current when the requested operating mode is a discharging mode.

4. The method of claim 1 , further comprising:
receiving a fast-charging voltage and current from an offboard fast-charging station, via the RESS, during a fast-charging operation;
wherein the requested operating mode is the charging mode, and controlling the requested operating mode occurs during the charging mode by controlling the fast-charging operation via the controller.

5. The method of claim 1 , wherein the requested operating mode is the discharging mode, and wherein controlling the requested operating mode includes energizing a rotary electric machine via the RESS and the PIM.

6. The method of claim 1 , wherein the predetermined prediction horizon includes at least five future time points relative to a present time point (k=0), including k =0.1s, 1s, 2s, 10s, and 20s.

7. The method of claim 1 , wherein the controller includes hierarchically-arranged first and second controllers, predicting the second pack current is accomplished via the second controller using a second one of the battery state models and communicated to the first controller, predicting the first pack current is accomplished via the first controller using a first of the battery state models, and predicting the total power capability and controlling the requested operating mode is accomplished via the first controller.

8. The method of claim 7 , wherein the first and second controllers are first and second vehicle integration control modules (VICMs) of a motor vehicle.

9. The method of claim 7 , wherein each of the battery state space models include a plurality of battery parameters for the first and second battery packs, respectively, including a state of charge, an open-circuit voltage, and a battery impedance.

10. The method of claim 1 , wherein the RESS includes a third battery pack that is serially-connected to the first and second battery packs, and wherein the first, second, and third battery packs each have a corresponding controller and a corresponding battery state space model.

11. A powertrain system comprising:
a rechargeable energy storage system (RESS) having:
series-connected first and second battery elements each connected to a DC voltage bus, and each having corresponding maximum voltage limits; and
first and second sensors connected to the respective first and second battery elements, each of the first and second sensors being operable for measuring a corresponding current and voltage of the first battery element and the second battery element;

a power inverter module (PIM) connected to the RESS;
a rotary electric machine connected to the PIM and having an output member coupled to a load; and
a controller operable for managing powerflow of the RESS, wherein the controller is programmed with a corresponding maximum current limit of the first and second battery elements, and is configured to:
predict a corresponding first and second current of the first battery element and the second battery element, respectively, using the maximum voltage limits;
receive a requested operating mode of the RESS;
select the first or second current as a selected current based on the requested operating mode, including selecting a minimum of the first or second current;
predict a voltage across each of the first battery element and the second battery element using the selected current and corresponding battery state space models;
predict a total power capability of the RESS over a predetermined prediction horizon using the predicted voltage to thereby generate a plurality of predicted power capability values; and
control the requested operating mode over the predetermined prediction horizon using the plurality of predicted power capability values.

12. The powertrain system of claim 11 , wherein the RESS is configured to receive a fast-charging voltage and current from an offboard fast-charging station during a fast-charging operation, the requested operating mode is the charging mode, and the controller is configured to control the fast-charging operation during the charging mode.

13. The powertrain system of claim 11 , wherein the requested operating mode is the discharging mode, and wherein the controller is configured to control the requested operating mode by energizing the rotary electric machine via the RESS and the PIM.

14. The powertrain system of claim 11 , wherein the predetermined prediction horizon includes at least five future time points.

15. The powertrain system of claim 14 , wherein relative to a current time point (k)=0 seconds (s), the at least five future time points include k=0.1s, 1 s, 2s, 10s, and 20s.

16. The powertrain system of claim 11 , wherein the controller includes hierarchically-arranged first and second controllers, the second controller is configured to predict the second current using a second one of the battery state space models and communicate the second current to the first controller, and the first controller is configured to predict the first current using a first one of the battery state space models, predict the total power capability, and control the requested operating mode.

17. The powertrain system of claim 16 , wherein the first and second controllers are respective first and second vehicle integration control modules (VICMs) of a motor vehicle, and wherein the load is a set of road wheels of the motor vehicle.

18. The powertrain system of claim 11 , wherein each of the battery state models include a plurality of battery parameters for the first and second battery elements, respectively, including a state of charge, an open-circuit voltage, and a battery impedance.

19. The powertrain system of claim 11 , wherein the RESS includes a third battery element connected in series with t

Assignees

• Gm Global Tech Operations Llc

Inventors

• Wang Yue-Yun
• Seeman Garrett M
• Piasecki Jeffrey S

Classifications

• H02J7/96

  in response to battery voltage · CPC title

• H02J7/94

  in response to battery current · CPC title

• B60L58/18

  of two or more battery modules · CPC title

• B60L58/12

  responding to state of charge [SoC] · CPC title

• B60L2240/549

  Current · CPC title