Reduced order battery thermal dynamics modeling for controls

Patent metadata

Field	Value
Publication number	US-9692093-B2
Application number	US-201414320722-A
Country	US
Kind code	B2
Filing date	Jul 1, 2014
Priority date	Jul 1, 2014
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A vehicle includes a traction battery that is comprised of a number of cells. A controller operates the traction battery according to a temperature for each of the cells. The temperature is based on a number of coefficients representing a contribution of at least one cell boundary thermal condition and a heat generated in the cell to a steady-state temperature at a predetermined location within the cell. The contributions may be filtered to predict a dynamic response of the temperature to changes in the boundary thermal conditions and the heat generated in the cell. The coefficients may be derived from a full-order model. The resulting reduced-order model requires less execution time while achieving accuracy similar to the full-order model. In addition, a range of characteristic temperatures may be obtained for each cell.

First claim

What is claimed is:

1. A vehicle comprising:
a traction battery including a plurality of cells; and
at least one controller programmed to operate the traction battery according to a temperature for each of the cells that is based on a plurality of coefficients representing a contribution of at least one cell boundary thermal condition and a heat generated in the cell to a steady-state temperature at a predetermined location within the cell, and filter the contribution of the at least one cell boundary thermal condition and the heat generated to predict a dynamic response to changes in the at least one cell boundary thermal condition and the heat generated.

2. The vehicle of claim 1 wherein the at least one controller is further programmed to filter the contribution of the at least one cell boundary thermal condition with a first time constant to predict a dynamic response to changes in the at least one cell boundary thermal condition and filter the contribution of the heat generated in the cell with a second time constant to predict a dynamic response to changes in the heat generated in the cell.

3. The vehicle of claim 1 wherein the coefficient associated with the contribution of the heat generated in the cell is derived from a model in which the cells are represented as a plurality of elements, and wherein the coefficient corresponding to each of the elements is derived from a system matrix defining interactions between the elements and an input matrix defining influence of the heat generated in the cell.

4. The vehicle of claim 3 wherein the predetermined location corresponds to the element in which the coefficient associated with the contribution caused by the heat generated in the cell is a maximum.

5. The vehicle of claim 3 wherein the predetermined location corresponds to the element in which the coefficient associated with the contribution caused by the heat generated in the cell is a minimum.

6. The vehicle of claim 1 wherein the at least one cell boundary condition includes a measured temperature.

7. The vehicle of claim 1 wherein the coefficients associated with the contribution of the at least one cell boundary thermal condition is derived from a model in which the cells are represented as a plurality of elements, and wherein the coefficients corresponding to each of the elements is derived from a system matrix defining interaction between the elements and an input matrix defining influence of the at least one cell boundary thermal condition.

8. The vehicle of claim 7 wherein the coefficients associated with the contribution of the at least one cell boundary thermal condition are set to a value of one.

9. A battery management system comprising:
at least one controller programmed to operate a battery cell according to a cell temperature that is based on a plurality of coefficients representing a contribution of at least one cell boundary condition and a heat generated in the battery cell to a steady-state temperature at a predetermined location within the battery cell and filter the contribution of the at least one cell boundary condition and the heat generated.

10. The battery management system of claim 9 wherein the at least one controller is further programmed to filter the contribution of the at least one cell boundary condition with a first time constant and filter the contribution of the heat generated in the cell with a second time constant.

11. The battery management system of claim 9 wherein the coefficients are derived from a system matrix that defines temperature interactions between a plurality of elements that represent the battery cell, a first input matrix defining influence of the at least one cell boundary condition, and a second input matrix defining influence of the heat generated in the battery cell.

12. The battery management system of claim 9 wherein a coefficient associated with the contribution of heat generated in the battery cell is a maximum value.

13. The battery management system of claim 9 wherein a coefficient associated with the contribution of heat generated in the battery cell is a minimum value.

14. A method of operating a traction battery including a plurality of cells, the method comprising:
outputting, by a controller, a temperature for each of the cells that is based on a plurality of coefficients, derived from a cell model as represented by a plurality of elements, representing a contribution of at least one cell boundary condition and a heat generated in the cell to a steady-state temperature of a predetermined location, corresponding to a selected one or more of the elements, within the cell; and
operating the traction battery according to the temperature of the cells.

15. The method of claim 14 further comprising filtering, by the controller, the contribution of the at least one cell boundary condition using a filter with a first time constant and the heat generated in the cell using a filter with a second time constant to filter changes in the steady-state temperature.

16. The method of claim 14 wherein the predetermined location corresponds to the element in which the coefficient associated with the contribution caused by the heat generated in the cell is a maximum.

17. The method of claim 14 wherein the predetermined location corresponds to the element in which the coefficient associated with the contribution caused by the heat generated in the cell is a minimum.

Assignees

• Ford Global Tech Llc

Inventors

• Lee Tae-Kyung
• Lin Xinfan

Classifications

• H01M10/625

  Vehicles · CPC title

• G05B15/02

  electric · CPC title

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• B60L58/24

  for controlling the temperature of batteries · CPC title

• H01M10/635 Primary

  based on ambient temperature · CPC title