Closed loop feedback control to mitigate lithium plating in electrified vehicle battery

Patent metadata

Field	Value
Publication number	US-2017203654-A1
Application number	US-201615001562-A
Country	US
Kind code	A1
Filing date	Jan 20, 2016
Priority date	Jan 20, 2016
Publication date	Jul 20, 2017
Grant date	—

Abstract

A vehicle having a traction battery with at least one cell includes a controller coupled to the traction battery and programmed to modify traction battery current in response to a difference between a lithium plating parameter target value and a lithium plating parameter actual value to reduce the difference. The lithium plating parameter or indicator may be based on a differential open circuit voltage of a battery cell, or a ratio of differential voltage of the at least one cell as a function of time to cell charging rate of the at least one cell.

First claim

What is claimed is:

1 . A vehicle comprising:
a traction battery having a plurality of cells; and a controller in communication with the traction battery and programmed to control the traction battery or the vehicle in response to a difference between a target value and a current value of a lithium plating indicator.

2 . The vehicle of claim 1 , the controller programmed to control the traction battery to reduce the difference toward zero.

3 . The vehicle of claim 1 , the lithium plating indicator being based on a difference between a measured open circuit voltage of the at least one cell and a previously stored open circuit voltage value.

4 . The vehicle of claim 3 , the measured open circuit voltage being based on a measured cell voltage, a measured cell current, and a previously stored cell internal resistance.

5 . The vehicle of claim 1 , the lithium plating indicator being based on a ratio of the differential cell voltage and cell current during charging of the traction battery.

6 . The vehicle of claim 1 , the controller further programmed to modify a previously stored lookup table of battery charging power vs. temperature in response to the difference exceeding a corresponding threshold.

7 . The vehicle of claim 1 , the controller further programmed to modify a previously stored accumulated lithium plating counter in response to the difference exceeding a corresponding threshold.

8 . The vehicle of claim 1 further comprising an internal combustion engine, the controller programmed to modify an operating point of the internal combustion engine to reduce the difference.

9 . The vehicle of claim 1 , the controller programmed to control regenerative braking current to reduce the difference.

10 . The vehicle of claim 1 , the controller programmed to operate at least one electrical accessory to increase traction battery current.

11 . The vehicle of claim 1 , the controller programmed to operate a traction battery heater to reduce the difference.

12 . A vehicle having a traction battery with at least one cell, comprising:
a controller coupled to the traction battery and programmed to modify traction battery current in response to a difference between a lithium plating parameter target value and a lithium plating parameter actual value to reduce the difference, the lithium plating parameter based on a ratio of differential voltage of the at least one cell as a function of time to cell charging rate of the at least one cell.

13 . The vehicle of claim 12 further comprising an internal combustion engine, the controller modifying an operating point of the internal combustion engine to reduce the difference.

14 . The vehicle of claim 13 , the controller modifying the operating point to reduce battery charging current.

15 . The vehicle of claim 12 , the controller reducing regenerative braking current to modify the battery current.

16 . The vehicle of claim 12 , the controller modifying a stored battery power limit associated with a current battery temperature in response to the difference exceeding a threshold.

17 . The vehicle of claim 12 , the controller tracking accumulated traction battery power during battery charging when the difference exceeds a corresponding threshold.

18 . The vehicle of claim 12 , the controller programmed to identify a lithium plated cell based on a relationship between open circuit voltage and traction battery state of charge (SOC) for SOC values below a threshold after discharging of the traction battery for a predetermined time to allow completion of lithium stripping.

19 . A method implemented by a vehicle controller in a vehicle having a traction battery, comprising:
controlling, by the controller, traction battery current in response to a difference between a lithium plating indicator target value and set point value to reduce the difference toward zero.

20 . The method of claim 19 wherein controlling the traction battery current comprises controlling a vehicle internal combustion engine.

Assignees

• Ford Global Tech Llc

Inventors

• He Chuan
• Wang Xu
• Chen Haiyan

Classifications

• B60L58/15

  Preventing overcharging · CPC title

• B60L58/27

  by heating · CPC title

• B60L58/14

  Preventing excessive discharging · CPC title

• Y10S903/907

  Electricity storage, e.g. battery, capacitor · CPC title

• H01M2010/4271

  Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing · CPC title