U.S. patent application number 11/440888 was filed with the patent office on 2006-12-21 for method and apparatus for estimating maximum power of battery by using internal resistance of the battery.
Invention is credited to Il Cho, Do Yang Jung, Do Youn Kim.
Application Number | 20060284618 11/440888 |
Document ID | / |
Family ID | 37452208 |
Filed Date | 2006-12-21 |
United States Patent
Application |
20060284618 |
Kind Code |
A1 |
Cho; Il ; et al. |
December 21, 2006 |
Method and apparatus for estimating maximum power of battery by
using internal resistance of the battery
Abstract
Disclosed is a method for estimating the maximum power of a
battery, which can inexpensively perform an estimation of the
maximum power of a battery in a relatively simple manner of using
the internal resistance of the battery, which has a correlation
with and a largest effect on the maximum power of the battery. The
method includes the steps of: measuring an internal resistance and
a temperature of the battery and estimating a state of charge, if
an estimation of the maximum power of the battery is requested; and
reading a value of the maximum power of the battery, which
corresponds to the measured temperature, the estimated state of
charge, and the measured internal resistance, from a table in which
the internal resistances and the maximum powers of the battery are
mapped according to the temperatures and states of charge.
Inventors: |
Cho; Il; (Seo-gu, KR)
; Kim; Do Youn; (Seo-gu, KR) ; Jung; Do Yang;
(Hwaseong-si, KR) |
Correspondence
Address: |
CANTOR COLBURN, LLP
55 GRIFFIN ROAD SOUTH
BLOOMFIELD
CT
06002
US
|
Family ID: |
37452208 |
Appl. No.: |
11/440888 |
Filed: |
May 25, 2006 |
Current U.S.
Class: |
324/430 ;
324/429; 324/431 |
Current CPC
Class: |
Y02T 10/70 20130101;
Y02T 10/7044 20130101; B60L 58/12 20190201; Y02T 10/705 20130101;
G01R 31/382 20190101; Y02T 10/7005 20130101; G01R 31/389 20190101;
G01R 31/374 20190101 |
Class at
Publication: |
324/430 ;
324/431; 324/429 |
International
Class: |
G01N 27/416 20060101
G01N027/416 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 2005 |
KR |
10-2005-0044862 |
Claims
1. A method of estimating a maximum power of a battery, comprising
the steps of: measuring an internal resistance and a temperature of
the battery and estimating its state of charge, if an estimation of
the maximum power of the battery is requested; and reading a value
of the maximum power of the battery, which corresponds to the
measured temperature, the estimated state of charge, and the
measured internal resistance, from a table in which the values of
the internal resistance and the maximum power of the battery are
mapped according to temperatures and states of charge.
2. The method as claimed in claim 1, further comprising the steps
of: measuring the internal resistances and maximum powers of the
battery according to the temperatures and states of charge; and
storing in a memory the table in which the internal resistances and
maximum powers of the battery have been measured according to the
temperatures and states of charge.
3. The method as claimed in claim 2, wherein the measurements of
the internal resistance and maximum power of the battery taken in
order to form the table, are actually carried out in a range of an
operational temperature and an operational state of charge.
4. The method as claimed in claim 1, wherein the internal
resistance is calculated by measuring the electric current and
voltage of the battery.
5. The method as claimed in claim 1, wherein the internal
resistance is calculated by measuring voltage and electric current
of the battery for a preset time, while a certain device having the
battery is driven.
6. An apparatus for estimating a maximum power of a battery,
comprising: a memory for storing a table in which internal
resistances and maximum powers of the battery are mapped according
to temperatures and states of charge; a sensor for sensing
temperature; an estimation unit for estimating the state of charge
of the battery; a measurement unit for measuring voltage and
electric current of the battery; and a controller for measuring the
temperature through the temperature sensor, estimating a state of
charge through the estimation unit, measuring the voltage and
electric current of the battery through the measurement unit so as
to calculate the internal resistance of the battery, and reading
the value of the maximum power of the battery, which corresponds to
the measured temperature, the estimated state of charge, and the
calculated internal resistance, from the table, when an estimation
of the maximum power of the battery is requested.
7. The apparatus as claimed in claim 6, wherein the controller
measures the real-time voltage and electric current of the battery
for a preset time, and calculates the internal resistance using the
measured current and voltage.
Description
[0001] This application claims the benefit of the filing date of
Korean Patent Application No. 2005-44862, filed on May 27, 2005, in
the Korean Intellectual Property Office, the disclosure of which is
incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the invention
[0003] The present invention relates to a method for estimating the
maximum power of a battery for a Hybrid Electric Vehicle (HEV),
more particularly to an apparatus and a method for estimating the
current maximum power of the battery by using the internal
resistance of the battery, one of various environment parameters,
which has the greatest effect on the maximum power of the battery
mounted on a vehicle.
[0004] 2. Description of the Prior Art
[0005] Electric vehicles use electric energy stored in a battery as
an energy source. Lithium-ion polymer batteries are mainly used as
the batteries for the electric vehicles, and researches for the
lithium-ion polymer batteries have been progressed.
[0006] The power and the like of the battery mounted on the
electric vehicle are controlled according to various control
information stored in a Battery Management System (BMS). It is
known that the estimation and the notification of the maximum power
of the current battery, among the functions of the BMS, configure
the most important information in the hybrid electric vehicle.
[0007] However, as the maximum power of the battery is sensitively
changed according to temperature, the state of charge (SOC), and
the state of health (SOH), it cannot be measured directly. Since
the maximum power of the battery has too intensive a nonlinearity,
it is impossible to measure the maximum power of the battery
directly. Thus, only a method for estimating the maximum power of
the battery indirectly has been proposed.
[0008] Nevertheless, a conventional art just discloses the method
for estimating the maximum power of the battery only using the
above-mentioned parameters such as temperature, the state of
charge, and the state of health. It does not disclose a method for
estimating the maximum power of the battery using the internal
resistance of the battery, which directly relate to the maximum
power of the battery.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to provide a method
for estimating the maximum power of a battery, which can
inexpensively perform the estimation the maximum power of a battery
in the relatively simple manner of using the internal resistance of
the battery which has a correlation with and the largest effect on
the maximum power of the battery.
[0010] In order to accomplish the object of the present invention,
there is provided a method of estimating a maximum power of a
battery, which includes the steps of: measuring an internal
resistance and a temperature of the battery and estimating its
state of charge, if an estimation of the maximum power of the
battery is requested; and reading a value of the maximum power of
the battery, which corresponds to the measured temperature, the
estimated state of charge, and the measured internal resistance,
from a table in which the values of the internal resistance and the
maximum power of the battery are mapped so as to correspond to each
temperature and each state of charge.
[0011] The present invention can easily and accurately estimate the
maximum power of the battery using the internal resistance of the
battery as well as various parameters having an effect on the
maximum power of the battery.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a flowchart illustrating a method for configuring
a table of the maximum power of a battery according to the
preferred embodiment of the present invention.
[0013] FIG. 2 is a view showing a table of the maximum power of the
battery according to the preferred embodiment of the present
invention.
[0014] FIG. 3 is a block diagram showing the structure of an
apparatus for estimating the maximum power of the battery according
to the preferred embodiment of the present invention.
[0015] FIG. 4 is a flowchart illustrating a method for estimating
the maximum power of the battery according to the preferred
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] Hereinafter, the preferred embodiment of the present
invention will be described with reference to the accompanying
drawings.
[0017] First, a method for configuring a table of the maximum power
of a battery according to the present invention will be described
with reference to FIG. 1.
[0018] An experimenter measures internal resistance values
according to temperatures and states of charge (step 100). At this
time, the environments, i.e. temperature and state of charge, under
which the internal resistance value of the battery is measured, are
within a range of an actually operational temperature and an
actually operational state of charge of a certain battery.
Specifically, with relation to the measurement of the internal
resistance value, voltages and currents are preferably measured
according to temperatures and states of charge, instead of directly
measuring the internal resistance values, so that each of the
internal resistance values is calculated by using the measured
value of the voltage and the current.
[0019] Then, the experimenter experimentally measures the values of
the maximum power of the battery according to temperatures and
states of charge in the same manner of measuring the internal
resistance values (step 102).
[0020] Next, the values obtained through the measurement at steps
100 and 102 are correlated with one another, and thereby a table
for the maximum power of the battery which shows the correlation of
the internal resistance value with the maximum power of the battery
is constructed. Then, the table of the maximum power of the battery
is stored in a memory of the battery management system provided
with the corresponding battery (step 104). As shown in FIG. 2,
internal resistance values and maximum powers of the battery, which
correspond to respective temperatures and states of charge, are
mapped in the table for the maximum power of the battery.
[0021] Hereinafter, the structure of an apparatus for estimating
the value of the maximum power of the battery using the table for
the maximum power of the battery will be described with respect to
FIG. 3.
[0022] A controller 200 entirely controls units of FIG. 3, and
performs processes for estimating the maximum power of the battery
according to the preferred embodiment of the present invention.
Specifically, after performing the measurement of temperature,
estimation of the state of charge, and the calculation of the
internal resistance value, the controller 200 reads the value of
the maximum power, which corresponds to temperatures, the states of
charge, and the internal resistance values obtained, from the table
for the maximum power of the battery, so as to easily and rapidly
estimate the value of the maximum power of the corresponding
battery.
[0023] A memory 202 stores a variety of information as well as the
processing program of the controller 200. Specifically, the table
for the maximum power of the battery shown in FIG. 2 is stored in
the memory, according to the preferred embodiment of the present
invention.
[0024] A unit 204 for measuring the current and the voltage
measures the current and the voltage of the battery in order to
estimate the maximum power of the corresponding battery and
provides the result to the controller 200.
[0025] A temperature sensor 206 measures the temperature, and
provides the result to the controller 200.
[0026] A unit for estimating the state of charge 208 estimates the
state of charge of the corresponding battery, and provides the
result to the controller 200.
[0027] Hereinafter, a method for estimating the maximum power of
the battery according to the preferred embodiment of the present
invention, which is applicable to the apparatus for estimating the
maximum power of the battery, will be described with reference to
the flowchart of FIG. 4.
[0028] When the estimation of the maximum power of the battery is
requested, the controller 200 of the apparatus for estimating the
maximum power of the battery measures the temperature through the
temperature sensor 206, and estimates the state of charge of the
corresponding battery through the unit 208 for estimating the state
of charge (steps 300 and 302). Next, the controller 200 measures
the voltage and the current of the corresponding battery through
the unit 204 for measuring the current and the voltage, and
calculates the value of the internal resistance in the
corresponding battery based on the obtained voltage and current
(step 306). Preferably, the real-time voltage and current is
measured for one second while a vehicle provided with the battery
is driven, and thereby the internal resistance is calculated by
using the obtained current and voltage.
[0029] When the calculation of the internal resistance value is
completed, the controller 200 reads the maximum power of the
battery corresponding to the obtained temperature, estimated state
of charge, and the calculated internal resistance value, from the
table of the maximum power of the battery stored in a memory 202
(308). Thus, the estimation of the maximum power of the
corresponding battery is completed.
INDUSTRIAL APPLICABILITY
[0030] According to the present invention, the table, which shows
the correlation of the internal resistance values and the maximum
powers of the battery according to the temperatures and states of
charge through the experiment, is configured in advance. Then, the
real-time internal resistance, the temperature, and the state of
charge are measured, and the maximum power of the battery
corresponding to the measurement result is read from the table,
thereby easily and accurately estimating the maximum power of the
battery without additional expense, which has too intensive a
nonlinearity and which cannot be directly estimated.
[0031] Although a preferred embodiment of the present invention has
been described for illustrative purposes, those skilled in the art
will appreciate that various modifications, additions and
substitutions are possible, without departing from the scope and
spirit of the invention as disclosed in the accompanying
claims.
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