Model predictive battery power limit estimation systems and methods

Patent metadata

Field	Value
Publication number	US-11208004-B2
Application number	US-201716346042-A
Country	US
Kind code	B2
Filing date	Oct 31, 2017
Priority date	Oct 31, 2016
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

Systems and methods for improving operation of an automotive battery system including an automotive electrical system comprising a battery system that uses operational parameters, predicted internal resistance of a battery expected over a prediction horizon, and real-time internal resistance of a battery to increase performance and reliability. The battery system includes a battery electrically coupled to electrical devices in the automotive system, sensors coupled to the battery that determine terminal voltage of battery, and a battery control system communicatively coupled to sensors. The battery control system determines a charging power limit used to control supply of electrical power to the battery when charging the battery, based on predicted internal resistance when measured terminal voltage of the battery is not greater than a lower voltage threshold and based on a real-time internal resistance of the battery when the measured terminal voltage of the battery is greater than the lower voltage threshold.

First claim

What is claimed is:

1. An automotive electrical system comprising a battery system, wherein the battery system comprises:
a battery comprising terminals configured to be electrically coupled to a one or more electrical devices in the automotive electrical system;
one or more sensors electrically coupled to the terminals of the battery, wherein the one or more sensors are configured to determine sensor data indicative of a measured terminal voltage of the battery; and
a battery control system communicatively coupled to the one or more sensors, wherein the battery control system is programmed to:
determine a predicted internal resistance of the battery, wherein the predicted internal resistance is determined based on operational conditions projected over a prediction horizon;
determine a charging power limit used to control supply of electrical power to the battery based at least in part on the predicted internal resistance when the measured terminal voltage of the battery is not greater than a lower voltage threshold; and

when the measured terminal voltage of the battery is greater than the lower voltage threshold:
determine a real-time internal resistance of the battery based at least in part the measured terminal voltage of the battery and a battery model that describes relationship between measured battery parameters and internal resistance of the battery; and
determine the charging power limit based at least in part on the real-time internal resistance to facilitate improving operational reliability of the battery.

2. The automotive electrical system of claim 1 , comprising:
an electrical power source electrically coupled to the terminals of the battery; and
a vehicle control system communicatively coupled to the battery control system and the electrical power source, wherein the vehicle control system is programmed to:
receive an indication of the charging power limit from the battery control system; and
instruct the electrical power source to supply electrical power to the battery in accordance with the charging power limit.

3. The automotive electrical system of claim 1 , wherein the battery control system is programmed to:
determine the real-time internal resistance corresponding with a instance in time during the prediction horizon;
control charging of the battery at the instance in time using the charging power limit determined based at least in part on the predicted internal resistance when the measured terminal voltage of the battery is not greater than a lower voltage threshold; and
control charging of the battery at the instances in time using the charging power limit determined based at least in part on the real-time internal resistance when the measured terminal voltage of the battery is greater than a lower voltage threshold.

4. The automotive electrical system of claim 1 , wherein:
the battery model comprises an RC circuit configured to describe the relationship of the internal resistance to the terminal voltage of the battery, current flow through the battery, and an open-circuit voltage of the battery; and
the internal resistance in the RC circuit comprises:
a first resistor electrically coupled in series between the open-circuit voltage and the terminal voltage of the battery; and
a second resistor and a capacitor electrically coupled in parallel between the open-circuit and the terminal voltage of the battery.

5. The automotive electrical system of claim 1 , wherein:
the one or more sensors are configured to determine sensor data indicative of a measured current flow through the battery; and
to determine the real-time internal resistance, the battery control system is programmed to:
determine open-circuit voltage of the battery; and
determine the real-time internal resistance of the battery based at least in part on difference between the measured terminal voltage of the battery and the open-circuit of the battery divided by the measured current flow through the battery.

6. The automotive electrical system of claim 5 , wherein, to determine the open-circuit voltage of the battery, the battery control system is programmed to:
determine an initial state-of-charge of the battery;
determine a current state-of-charge of the battery based at least in part on current flow through the battery between the initial state-of-charge and the current state-of-charge; and
determine the open-circuit voltage of the battery based at least in part on the current state-of charge of the battery.

7. The automotive electrical system of claim 5 , wherein, to determine the open-circuit voltage of the battery, the battery control system is programmed to:
instruct the battery system to electrically disconnect the battery from the one or more electrical devices; and
determine the open-circuit voltage of the battery based at least in part on the measured terminal voltage after the battery is maintained electrically disconnected from the one or more electrical devices a duration greater than a rest duration threshold.

8. The automotive electrical system of claim 1 , wherein:
the one or more sensors are configured to determine sensor data indicative of measured current flow through the battery; and
to determine the predicted internal resistance, the battery control system is programmed to:
determine a predicted driving pattern, wherein the predicted driving pattern comprises projected battery states over the prediction horizon;
determine a voltage change between the measured terminal voltage relative to a previous terminal voltage of the battery; and
determine the predicted internal resistance based at least in part on the voltage change multiplied by the measured current flow through the battery and divided by the predicted driving pattern.

9. The automotive electrical system of claim 1 , comprising a temperature sensor configured to determine sensor data indicative of temperature of the battery, wherein the battery control system is programmed to adjust model parameters of the battery model based at least in part on the temperature of the battery.

10. The automotive electrical system of claim 1 , wherein the battery control system is programmed to instruct the battery system to electrically disconnect the battery from the one or more electrical devices when the measured terminal voltage of the battery exceeds an upper voltage threshold greater than the lower voltage threshold to facilitate improving lifespan of the battery.

11. The automotive electrical system of claim 1 , wherein the battery comprises:
a lithium-ion battery cell electrically coupled between the terminals; or
a lithium-ion battery module comprising a plurality of battery cells electrically coupled between the terminals.

12. A method for controlling charging of a battery cell in an automotive vehicle, comprising:
determining, using a control system, measured terminal voltage of the battery cell based at least in part on sensor data received from a first sensor;
determining, using the control system, a predicted internal resistance of the battery cell, wherein the predicted internal resistance comprises based on projected operational conditions projected over a prediction horizon;
determining, using the control system, a charging power limit by:
determining the charging power limit based at least in part on the predicted internal resistance of the battery cell when the measured terminal voltage of the battery cell is not greater than a lower voltage threshold; and
determining the charging power limit based at least in part on a real-time internal resistance of the battery cell when the measured terminal voltage of the battery cell is greater than the lower volta

Assignees

• Cps Tech Holdings Llc
• Cps Tech Holdings

Inventors

• Jin Zhihong H

Classifications

• B60L58/15

  Preventing overcharging · CPC title

• B60L58/16

  responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH] · CPC title

• B60L2260/50

  by future state prediction · CPC title

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title

• B60L2240/545

  Temperature · CPC title