Battery state of charge estimator

Patent metadata

Field	Value
Publication number	US-2017285107-A1
Application number	US-201515511948-A
Country	US
Kind code	A1
Filing date	Sep 15, 2015
Priority date	Sep 16, 2014
Publication date	Oct 5, 2017
Grant date	—

Abstract

A battery monitoring device includes a first coil positioned within a cell of a battery, a second coil positioned to be magnetically coupled to the first coil through active material that is contained within the cell, and a controller that is configured to apply an electrical current to one of the first and second coils, detect induced electrical current in the other of the first and second coils, and determine a state-of-charge (SOC) of the battery based on the induced electrical current.

First claim

1 . A battery monitoring device, comprising:
a first coil positioned within a cell of a battery; a second coil positioned to be magnetically coupled to the first coil through active material that is contained within the cell; and a controller configured to:
apply an electrical current to one of the first and second coils;
detect induced electrical current in the other of the first and second coils; and
determine a state-of-charge (SOC) of the battery based on the induced electrical current.

2 . The battery monitoring device of claim 1 , wherein the controller is configured to:
determine an amount of Fe(II) and Fe(III) in the active material based on the induced electrical current; and determine the SOC of the battery based on the amount of Fe(II) and Fe(III).

3 . The battery monitoring device of claim 2 , wherein the controller is configured to determine the SOC based on linear proportions of the amounts of Fe(II) and Fe(III).

4 . The battery monitoring device of claim 1 , wherein the second coil is positioned within the cell of the battery.

5 . The battery monitoring device of claim 1 , wherein the second coil is positioned external to the cell of the battery.

6 . The battery monitoring device of claim 5 , wherein the controller is further configured to apply a current to the second coil to inductively charge the battery via the first coil.

7 . The battery monitoring device of claim 1 , wherein the battery is a lithium-ion battery.

8 . The battery monitoring device of claim 1 , wherein the first coil is positioned on a current collector within the cell of the battery.

9 . The battery monitoring device of claim 1 , wherein the applied electrical current is an AC current.

10 . The battery monitoring device of claim 1 , wherein the controller is configured to monitor the SOC of the battery during usage of the battery.

11 . A method of determining a state-of-charge (SOC) of a battery, comprising:
passing a first current through a first coil; measuring a second current in a second coil that is induced by the first current in the first coil after having passed as a magnetization through a magnetic medium that includes at least a portion of the battery; determining a SOC of the battery based on the measured second current.

12 . The method of claim 11 , further comprising:
determining an amount of Fe(II) and Fe(III) in the magnetic medium in the battery based on the measured second current; and determining a state-of-charge (SOC) of the battery based on the amount of Fe(II) and Fe(III).

13 . The method of claim 12 , further comprising determining the SOC based on linear proportions of the amounts of Fe(II) and Fe(III).

14 . The method of claim 11 , wherein the second coil is positioned within the portion of the battery.

15 . The method of claim 11 , wherein the second coil is positioned external to the cell of the battery.

16 . The method of claim 15 , further comprising applying a current to the second coil to inductively charge the battery via the first coil.

17 . The method of claim 11 , wherein the battery is a lithium-ion battery.

18 . The method of claim 11 , wherein the first coil is positioned on a current collector within the cell of the battery.

19 . The method of claim 11 , wherein the applied electrical current is an AC current.

20 . The method of claim 1 , further comprising monitoring the SOC of the battery during usage of the battery.

Assignees

• Univ Wayne State

Inventors

• Gholam-Abbas Nazri

Classifications

• H02J7/84

  Control of state of health [SOH] · CPC title

• H02J7/80

  including monitoring or indicating arrangements · CPC title

• H02J7/82

  Control of state of charge [SOC] · CPC title

• H02J7/50

  acting upon multiple batteries simultaneously or sequentially · CPC title

• H02J7/00

  Circuit arrangements for charging or discharging batteries or for supplying loads from batteries · CPC title