Battery management apparatus and method thereof

Patent metadata

Field	Value
Publication number	US-11073566-B2
Application number	US-201716308953-A
Country	US
Kind code	B2
Filing date	Oct 18, 2017
Priority date	Dec 5, 2016
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

Disclosed is a battery management apparatus and method. The battery management apparatus according to an embodiment of the present disclosure may be configured to, when the voltage of a battery being discharged is equal to or lower than a preset discharge threshold voltage, predict the time left for a lower limit of discharge voltage preset lower than the discharge threshold voltage from the current time, and maintain or adjust the output parameter of the battery based on the predicted remaining time.

First claim

What is claimed is:

1. A battery management apparatus, comprising:
a voltage measuring unit configured to measure a voltage of a battery;
a current measuring unit configured to measure a current of the battery; and
a control unit configured to determine a state of charge based on at least one of the measured voltage or the measured current during discharging of the battery,
wherein the control unit is configured to:
determine if the voltage of the battery reaches a preset discharge threshold voltage,
when the voltage of the battery is determined to have reached the discharge threshold voltage, record an arrival time at which the voltage of the battery reached the discharge threshold voltage, and determine a discharge profile based on the state of charge, wherein data defining the discharge profile is recorded through previous experimentation using a predetermined level of constant current,
obtain a maximum value of resistance change ratio preset for the discharge profile,
predict a remaining time until the voltage of the battery reaches a lower limit of discharge voltage from a current time that is equal to or later than the arrival time based at least in part on the following equation:

t
r

=

(

V
min

-

V
threshold

)

I
0

⁡

[

dR
dt

]

max

wherein t r is the remaining time, V threshold is the discharge threshold voltage, V min is the lower limit of discharge voltage that is preset lower than the discharge threshold voltage, I 0 is the current of the battery measured at the current time, and (dR/dt) max is the maximum value of resistance change ratio, and
output a message indicating the predicted remaining time.

2. The battery management apparatus according to claim 1 , wherein the control unit is configured to:
calculate an average value of absolute values of the current of the battery measured at least a predetermined number of times for a predetermined time in the past on the basis of the arrival time,
determine a weight for correcting the remaining time based on the average value and the constant current, and
predict the remaining time using the following equation:

t
r

=

K
⁡

(

V
min

-

V
threshold

)

I
0

⁡

[

dR
dt

]

max

wherein K is the weight.

3. The battery management apparatus according to claim 2 , wherein the control unit is configured to:
when the average value is larger than the constant current by a first reference value or more, allocate a value that is smaller than 1 and larger than 0 to the weight,
when the average value is smaller than the constant current by a second reference value or more, allocate a value that is larger than 1 to the weight, and
when the average value is smaller than a value obtained by adding the first reference value to the constant current and larger than a value obtained by subtracting the second reference value from the constant current, allocate 1 to the weight.

4. The battery management apparatus according to claim 1 , further comprising:
a temperature measuring unit configured to measure a temperature of the battery,
wherein the control unit is configured to determine the state of charge further based on the measured temperature during discharging of the battery.

5. The battery management apparatus according to claim 1 , wherein the control unit is configured to:
determine if the predicted remaining time is equal to or more than an output maintenance time, and
when the predicted remaining time is determined to be less than the output maintenance time, determine a target derating current value in derating mode, and
the output maintenance time is requested from a load device communicably connected to the battery management apparatus.

6. The battery management apparatus according to claim 5 , wherein the control unit is configured to:
determine the target derating current value using the following equation:

I
derate

=

V
min

-

V
threshold

+

I
0

×

R
0

R
0

+

[

dR
dt

]

max

⁢

t
m

wherein R 0 is a preset internal resistance of the battery, t m is the output maintenance time, and I derate is the target derating current value.

7. The battery management apparatus according to claim 1 , wherein the control unit is configured to:
periodically update the remaining time until the voltage of the battery is higher than the discharge threshold voltage reached at the arrival time.

8. The battery management apparatus according to claim 1 , wherein the control unit is configured to:
when the battery starts charging again before the voltage of the battery is higher than the discharge threshol

Assignees

• Lg Chemical Ltd

Inventors

• Cha Sun-Young
• Joe Won-Tae

Classifications

• H02J7/585

  Sequential battery discharge in systems with a plurality of batteries · CPC title

• H01M10/486

  for measuring temperature · CPC title

• G01R19/12

  Measuring rate of change · CPC title

• G01R31/367 Primary

  Software therefor, e.g. for battery testing using modelling or look-up tables · CPC title

• G01R19/16566

  Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533 · CPC title