Battery pack and method of managing the battery pack

Patent metadata

Field	Value
Publication number	US-2016344068-A1
Application number	US-201615145885-A
Country	US
Kind code	A1
Filing date	May 4, 2016
Priority date	May 19, 2015
Publication date	Nov 24, 2016
Grant date	—

Abstract

A battery pack including: a lithium air battery configured to receive air and discharge a discharge gas, the lithium air battery including a cell module configured to generate electricity based on oxidation of a lithium metal and reduction of oxygen; and a battery management unit configured to control charging and discharging of the lithium air battery, wherein the battery management unit includes a measurement unit configured to measure a composition ratio of the discharge gas, measure a current, and to generate discharge gas data and current data; a capacity estimation unit configured to estimate a present capacity of the lithium air battery based on the discharge gas data and the current data and to generate a present capacity data; and a state of health estimation unit configured to estimate a state of health of the lithium air battery based on the present capacity data.

First claim

What is claimed is:

1 . A battery pack comprising:
a lithium air battery configured to receive air and discharge a discharge gas, the lithium air battery comprising
a cell module configured to generate electricity based on oxidation of a lithium metal and reduction of oxygen; and
a battery management unit configured to control charging and discharging of the lithium air battery,
wherein the battery management unit comprises
a measurement unit configured to measure a composition ratio of the discharge gas, measure a current, and to generate discharge gas data and current data;
a capacity estimation unit configured to estimate a present capacity of the lithium air battery based on the discharge gas data and the current data and to generate a present capacity data; and
a state of health estimation unit configured to estimate a state of health of the lithium air battery based on the present capacity data.

2 . The battery pack of claim 1 , wherein the capacity estimation unit is further configured to generate the present capacity data by integrating a charging current when a carbon composition ratio acquired by detecting carbon oxide or carbon dioxide included in the discharge gas is less than a predetermined threshold carbon composition ratio.

3 . The battery pack of claim 1 , further comprising a memory unit configured to store initial capacity data and deterioration capacity data.

4 . The battery pack of claim 3 , wherein the state of health estimation unit is further configured to acquire
a threshold charging capacity of a present cycle, a threshold charging capacity of a first cycle, and a threshold charging capacity of a deterioration cycle based on the present capacity data, the initial capacity data, and the deterioration capacity data, and to estimate a first state of health of the lithium air battery by dividing a difference between the threshold charging capacity of the present cycle and the threshold charging capacity of the deterioration cycle by a difference between the threshold charging capacity of the first cycle and the threshold charging capacity of the deterioration cycle.

5 . The battery pack of claim 1 , wherein the cell module comprises a positive electrode layer, a negative electrode layer, and an electrolyte layer between the positive electrode layer and the negative electrode layer, and wherein the electrolyte layer comprises a non-aqueous electrolyte.

6 . The battery pack of claim 5 , wherein the non-aqueous electrolyte comprises at least one of a carbonate solvent, an ester solvent, an ether solvent, a ketone solvent, an organosulfur solvent, an organophosphorous solvent, and an aprotic solvent.

7 . The battery pack of claim 1 , further comprising an internal resistance estimation unit configured to
estimate a present internal resistance of the lithium air battery based on voltage data generated by the measurement unit by measuring a voltage of the lithium air battery and the present current data, and generate present internal resistance data, wherein the state of health estimation unit is further configured to estimate a second state of health of the lithium air battery based on the present internal resistance data.

8 . The battery pack of claim 7 , further comprising a memory unit configured to store present internal resistance data and deterioration internal resistance data.

9 . The battery pack of claim 8 , wherein the state of health estimation unit is further configured to acquire a present internal resistance in a present charging cycle, an initial internal resistance in a first charging cycle, and a deterioration internal resistance in a deterioration charging cycle based on the present internal resistance data, the initial internal resistance data, and the deterioration internal resistance data, and
to estimate the second state of health of the lithium air battery by dividing a difference between the present internal resistance of the deterioration charging cycle and the present internal resistance of the present charging cycle by a difference between the present internal resistance of the deterioration charging cycle and the internal resistance of the first charging cycle.

10 . The battery pack of claim 9 , wherein the state of health estimation unit is configured such that the present internal resistance of the present charging cycle, the internal resistance of the first charging cycle, and the internal resistance of the deterioration charging cycle are each independently acquired at a same temperature and under the same state of health conditions.

11 . The battery pack of claim 9 , wherein the state of health estimation unit is further configured to estimate a state of health of the lithium air battery based on the first state of health and the second state of health.

12 . The battery pack of claim 11 , wherein the state of health is an average of the first state of health and the second state of health.

13 . A method of managing a battery pack, the battery pack comprising
a lithium air battery configured to receive air and discharge a discharge gas and comprising a cell module configured to generate electricity based on oxidation of a lithium metal and reduction of oxygen, and a battery management unit configured to control charging and discharging of the lithium air battery, the method comprising: measuring a composition ratio of the discharge gas and a current and generating discharge gas data and current data; estimating a present capacity of the lithium air battery based on the discharge gas data and the current data and generating present capacity data; and estimating a first state of health of the lithium air battery based on the present capacity data, an initial capacity data, and a deterioration capacity data.

14 . The method of claim 13 , further comprising:
calculating a carbon composition ratio of the discharge gas based on the discharge gas data; comparing the carbon composition ratio with a predetermined threshold carbon composition ratio; and integrating a charging current when the carbon composition ratio is less than the predetermined threshold carbon composition ratio.

15 . The method of claim 13 , wherein the estimating of the first state of health of the lithium air battery comprises
acquiring a threshold charging capacity of a present cycle, a threshold charging capacity of a first charging cycle, and a threshold charging capacity of a deterioration cycle based on the present capacity data, the initial capacity data, and the deterioration capacity data,
wherein the first state of health of the lithium air battery is estimated by dividing a difference between the threshold charging capacity of the present cycle and the threshold charging capacity of the deterioration cycle by a difference between the threshold charging capacity of the first cycle and the threshold charging capacity of the deterioration cycle.

16 . The method of claim 13 , further comprising:
measuring a voltage of the lithium air battery; estimating a present internal resistance of the lithium air battery based on the voltage data and the current data and generating present internal resistance data; and estimating a second state of health of the lithium air battery based on the present internal resistance data, an initial internal resistance data, and a deterioration internal resistance data.

17 . The method of claim 16 , wherein the present internal resistance of the current charging cycle, the initial internal resistance of the first charging cycle, and the present internal resistance

Assignees

• Samsung Electronics Co Ltd

Inventors

• Kim Taeyoung
• Lee Dongjoon
• Im Dongmin

Classifications

• H02J7/84

  Control of state of health [SOH] · CPC title

• H02J7/82

  Control of state of charge [SOC] · CPC title

• H01M10/4257 Primary

  Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries · CPC title

• G01R31/382

  Arrangements for monitoring battery or accumulator variables, e.g. SoC · CPC title

• H01M12/08

  composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type · CPC title