Battery system identification through impulse injection

• US 10,451,678 B2
• Filed: 07/17/2014
• Issued: 10/22/2019
• Est. Priority Date: 07/17/2014
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Lee, Tae-Kyung
• Primary Examiner(s): Le, John H
• Application Number:
  US14/334,364
• Publication Number:
  US 20160018471A1
• Time in Patent Office: 1,923 Days
• Field of Search: 702 63, 320106, 320109, 320132, 320145, 324428, 324430
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/385 Arrangements for measuring battery or accumulator variables for monitoring G01R31/382

Abstract

Vehicle systems and methods can include a traction battery and a controller to operate the traction battery according to current limits of a battery model identified from a battery response to a pulse of current injected into the battery while the battery is not being discharged to propel the vehicle or being charged. The pulse can have a sampling time and magnitude. The response is battery terminal voltages measurements at every sampling time during a set duration. The controller can implement a state estimator configured to output battery state uses a battery impulse response. The pulse input into the battery can be a current signal and the measured battery response can be a voltage. The controller can select a time period for the pulse input and battery measurement response to be when the controller is not charging the battery or drawing current from the battery to propel the vehicle.

Claims

1. A vehicle comprising:

a traction battery including terminals and battery cells; and

at least one controller to;

inject a current impulse at the terminals while the traction battery is not being discharged or charged,

sense an output from the terminals after injecting the impulse, and

operate the traction battery according to power limits defined by a battery model that is updated with the sensed output from the terminals.

2. The vehicle of claim 1 wherein the at least one controller is configured to produce a discrete space model of the traction battery and to convert the discrete space model to a continuous state space model.

3. The vehicle of claim 2 wherein the operational limits are based on the continuous state space model.

4. The vehicle of claim 3 wherein the at least one controller is configured to use Eigendecomposition to transform the continuous state space model to derive mathematical expressions to estimate the power limits.

5. The vehicle of claim 1 wherein the at least one controller injects the current impulse during a current pulse injection period that is free from battery transients.

6. The vehicle of claim 5 wherein the sensing occurs during the current pulse injection period.

7. The vehicle of claim 6 wherein the current impulse has an amplitude of 1 ampere and a duration of 0.1 second.

8. The vehicle of claim 1, wherein the battery model includes a state space model.