FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
“BATTERY MANAGEMENT SYSTEM, BATTERY PACK, ELECTRIC
VEHICLE AND BATTERY CHARGING TIME PREDICTION
METHOD”
LG ENERGY SOLUTION, LTD., Tower1, 108, Yeouidaero, Yeongdeungpo-gu, Seoul 07335, Republic of Korea
The following specification particularly describes the invention and the manner in which it is
to be performed.
1
DESCRIPTION
TITLE OF INVENTION
BATTERY MANAGEMENT SYSTEM, BATTERY PACK, ELECTRIC
5 VEHICLE AND BATTERY CHARGING TIME PREDICTION METHOD
TECHNICAL FIELD
The present disclosure relates to a technology for estimating a remaining charging
time of a battery.
10 The present application claims priority to Korean Patent Application No. 10-2022-
0116578 filed on September 15, 2022 in the Republic of Korea and Korean Patent
Application No. 10-2023-0057146 filed on May 2, 2023 in the Republic of Korea, the
disclosures of which are incorporated herein by reference.
15 BACKGROUND ART
Recently, the demand for portable electronic products such as notebook computers,
video cameras and portable telephones has increased sharply, and electric vehicles, energy
storage batteries, robots, satellites and the like have been developed in earnest.
Accordingly, high-performance batteries allowing repeated charging and discharging are
20 being actively studied.
Batteries commercially available at present include nickel-cadmium batteries,
nickel hydrogen batteries, nickel-zinc batteries, lithium batteries and the like. Among
them, the lithium batteries are in the limelight since they have almost no memory effect
2
compared to nickel-based batteries and also have very low self-charging rate and high
energy density.
When charging a battery with constant current, if the charge rate (may also be
referred to as ‘C-rate’) of the charging current is low, a very long time is required to fully
5 charge the battery. On the other hand, if the charge rate is too high, it causes the side
effect that the battery deteriorates quickly. Therefore, during constant-current charging, it
is necessary to gradually adjust the charging current according to the state of the battery.
For reference, the charge rate (C-rate) is the value obtained by dividing the charging
current by the maximum capacity of the battery, and ‘C’ is used as the unit.
10 A ‘multi-stage constant-current charging protocol’ may be mainly used to change
various charge rates predetermined for constant-current charging in stages. A charging
map can be created for each of a plurality of temperature sections, and each charging map
is a table or function in which the relationship between the plurality of reference current
values (charge rates) and the plurality of transition conditions associated with the specific
15 temperature section is recorded. If the state of the battery satisfies a specific transition
condition (e.g., SOC reaches 60%) while charging using any one of the plurality of
reference current values recorded in the specific charging map, the charging current of the
next charge rate may be supplied to the battery.
Relatedly, during battery charging, it is necessary to notify the user of how much
20 time remains until the SOC of the battery reaches a target SOC (e.g., fully charged state).
Conventionally, the remaining charging time to the target SOC was predicted by
assuming that the output power from the charger was large enough to allow the charging
current of the charge rate according to the multi-stage constant-current charging protocol to
3
flow through the battery.
However, the maximum output power of the charger may sometimes be less than
the charging power required for constant-current charging of the battery, and in such cases,
the battery is charged using the constant-power charging mode instead of the constant5 current charging mode. There is a big difference in battery charging speed depending on
whether the constant-current charging mode or the constant-power charging mode is
implemented. Therefore, in charging conditions where the output power of the charger is
insufficient, there is a problem that there is a large deviation between the predicted value of
the remaining charging time and the charging time actually consumed.
10
DISCLOSURE
Technical Problem
The present disclosure is designed to solve the problems of the related art, and
therefore the present disclosure is directed to providing a battery management system that
15 can improve the prediction accuracy of the total remaining time until the SOC of the
battery reaches the target SOC by repeating the process of predicting the time required for
charging at each stage (SOC range) based on the comparison result of the charging power
required for the corresponding stage and the maximum output power of a charger while
charging the battery according to a multi-stage constant-current charging protocol; a
20 battery pack including the battery management system; an electric vehicle including the
battery pack; and a battery charging time prediction method that can be implemented in the
battery management system.
These and other objects and advantages of the present disclosure may be
4
understood from the following detailed description and will become more fully apparent
from the exemplary embodiments of the present disclosure. Also, it will be easily
understood that the objects and advantages of the present disclosure may be realized by the
means shown in the appended claims and combinations thereof.
5
Technical Solution
A battery management system according to an aspect of the present disclosure
comprises a memory configured to store a plurality of reference charging maps associated
with a plurality of temperature sections; a sensing unit configured to detect voltage, current,
10 and temperature of a battery; and a control unit configured to determine an estimated SOC
value of the battery based on the voltage detection value and the current detection value of
the battery. Each of the plurality of reference charging maps includes first to Mth
reference current values and first to Mth reference power curves associated with first to Mth
SOC sections. M is a natural number greater than or equal to 2. The control unit may be
configured to obtain a mth reference power curve and a mth 15 reference current value
associated with a mth SOC section to which the estimated SOC value belongs, from the
reference charging map associated with the temperature section to which the temperature
detection value of the battery belongs. m is a natural number less than or equal to M. The
control unit may be configured to determine a mth predicted charging time value, which
represents a time required for an SOC of the battery to reach an end point of the mth 20 SOC
section, according to the result of comparing a maximum output power of a charger that
supplies charging power to the battery and the mth reference power curve, based on the
difference between the end point of the mth SOC section and the estimated SOC value, and
5
at least one of the mth reference current value, the maximum output power and the mth
reference power curve.
The control unit may be configured to determine an expected time required when
performing a constant-current charging mode using the mth reference current value until the
SOC of the battery reaches the end point of the mth 5 SOC section from the estimated SOC
value as the mth predicted charging time value, in response to that the maximum output
power of the charger is greater than or equal to a maximum power value of the mth
reference power curve.
The control unit may be configured to determine an expected time required when
10 performing a constant-power charging mode using the maximum output power until the
SOC of the battery reaches the end point of the mth SOC section from the estimated SOC
value as the mth predicted charging time value, in response to that the maximum output
power of the charger is less than or equal to a minimum power value of the mth reference
power curve.
15 The control unit may be configured to, in response to that the maximum output
power of the charger is between a minimum power value and a maximum power value of
the mth reference power curve, determine an intersection SOC, which represents SOC at an
intersection point of the mth reference power curve and the maximum output power, and
determine the mth predicted charging time value based on the estimated SOC value, the
intersection SOC, the end point of the mth SOC section, the mth 20 reference current value, the
maximum output power, and the mth reference power curve.
The control unit may be configured to determine a mth predicted constant-current
charging time value, which represents an expected time required when performing a
6
constant-current charging mode using the mth reference current value until the SOC of the
battery reaches the intersection SOC from the estimated SOC value, determine a mth
predicted constant-power charging time value, which represents an expected time required
when performing a constant-power charging mode using the maximum output power until
the SOC of the battery reaches the end point of the mth 5 SOC section from the intersection
SOC, and determine the mth predicted charging time value to be equal to the sum of the mth
predicted constant-current charging time value and the mth predicted constant-power
charging time value.
The control unit may be configured to further determine a predicted temperature
value at a start point of a (m+1)th 10 SOC section, when at least one SOC section subsequent
to the mth SOC section exists among the first to Mth SOC sections.
The control unit may be configured to determine a predicted temperature change
amount until the SOC of the battery reaches the start point of the (m+1)
th SOC section
from the estimated SOC value, based on the mth reference current value and the mth
15 predicted charging time value, and determine the predicted temperature value at the start
point of the (m+1)
th SOC section by adding the predicted temperature change amount from
the estimated SOC value to the end point of the mth SOC section to the temperature
detection value.
The control unit may be configured to, for k being a natural number greater than or
20 equal to (m+1) and less than or equal to M, in response to completing the determination of
the predicted temperature value at a start point of a k
th SOC section, obtain a kth reference
power curve and a kth reference current value associated with the kth SOC section from the
reference charging map associated with the temperature section to which the predicted
7
temperature value at the start point of the kth SOC section belongs, and determine a kth
predicted charging time value, which represents the time required for the SOC of the
battery to reach the end point from the start point of the kth SOC section, according to the
result of comparing the maximum output power of the charger and the kth reference power
curve, based on a size of the kth SOC section, and at least one of the kth 5 reference current
value, the maximum output power, and the kth reference power curve.
The control unit may be configured to, in response to completing the
determination of the predicted charging time value in the Mth SOC section, determine the
total remaining time until the SOC of the battery reaches the end point of the Mth SOC
section from the estimated SOC value by adding the mth to Mth 10 predicted charging time
values determined for the mth to Mth SOC sections.
A battery pack according to another aspect of the present disclosure may comprise
the battery management system.
An electric vehicle according to still another aspect of the present disclosure may
15 comprise the battery pack.
A battery charging time prediction method according to still another aspect of the
present disclosure comprises determining an estimated SOC value of a battery based on a
voltage detection value and a current detection value of the battery; obtaining a mth
reference power curve and a mth reference current value associated with a mth SOC section
20 (m is a natural number less than or equal to M) to which the estimated SOC value belongs,
from a reference charging map associated with a temperature section to which a
temperature detection value of the battery belongs, among a plurality of reference charging
maps associated with a plurality of temperature sections - each reference charging map
8
including first to Mth reference current values and first to Mth reference power curves
associated with first to Mth SOC sections (M is a natural number greater than or equal to 2)
-; and determining a mth predicted charging time value, which represents a time required
for an SOC of the battery to reach an end point of the mth SOC section, according to the
5 result of comparing a maximum output power of a charger that supplies charging power to
the battery and the mth reference power curve, based on the difference between the end
point of the mth SOC section and the estimated SOC value, and at least one of the mth
reference current value, the maximum output power and the mth reference power curve.
The step of determining the mth predicted charging time value may be determining
10 an expected time required when performing a constant-current charging mode using the
mth reference current value until the SOC of the battery reaches the end point of the mth
SOC section from the estimated SOC value as the mth predicted charging time value, in
response to that the maximum output power of the charger is greater than or equal to a
maximum power value of the mth reference power curve.
The step of determining the mth 15 predicted charging time value may be determining
an expected time required when performing a constant-power charging mode using the
maximum output power until the SOC of the battery reaches the end point of the mth SOC
section from the estimated SOC value as the mth predicted charging time value, in response
to that the maximum output power of the charger is less than or equal to a minimum power
value of the mth 20 reference power curve.
The step of determining the mth predicted charging time value may include, in
response to that the maximum output power of the charger is between a minimum power
value and a maximum power value of the mth reference power curve, determining an
9
intersection SOC associated with the same power value as the maximum output power
from the mth reference power curve; determining a mth predicted constant-current charging
time value, which represents an expected time required when performing a constantcurrent charging mode using the mth reference current value until the SOC of the battery
reaches the intersection SOC from the estimated SOC value; determining a mth 5 predicted
constant-power charging time value, which represents an expected time required when
performing a constant-power charging mode using the maximum output power until the
SOC of the battery reaches the end point of the mth SOC section from the intersection
SOC; and determining the mth predicted charging time value to be equal to the sum of the
mth predicted constant-current charging time value and the mth 10 predicted constant-power
charging time value.
Advantageous Effects
According to at least one of the embodiments of the present disclosure, during
15 battery charging according to the multi-stage constant-current charging protocol, the
prediction accuracy of the total remaining time until the SOC of the battery reaches the
target SOC can be improved by repeating the process of predicting the time required for
charging at the corresponding stage, based on the result of comparing the charging power
required at each stage (SOC range) and the maximum output power of the charger.
20 In addition, according to at least one of the embodiments of the present disclosure,
the prediction accuracy of charging time for each stage can be improved by predicting the
battery temperature change amount at each stage, and selecting a charging map used to
predict the charging time at the subsequent stage using the predicted battery temperature
10
change amount.
In addition, according to at least one of the embodiments of the present disclosure,
by adjusting the end point of each stage according to the difference between the predicted
temperature change amount value and the actual temperature change amount for the
5 corresponding stage, the safety of the charging procedure that will be resumed in the future
can be improved, and also battery life may be prolonged.
The effects of the present disclosure are not limited to the effects mentioned above,
and other effects not mentioned will be clearly understood by those skilled in the art from
the description of the claims.
10
DESCRIPTION OF DRAWINGS
The accompanying drawings illustrate a preferred embodiment of the present
disclosure and together with the foregoing disclosure, serve to provide further
understanding of the technical features of the present disclosure, and thus, the present
15 disclosure is not construed as being limited to the drawing.
FIG. 1 is a drawing illustrating the configuration of an electric vehicle according to
the present disclosure.
FIGS. 2 to 4 are diagrams referenced to explain an exemplary reference charging
map used in a charging procedure using a multi-stage constant-current charging protocol.
20 FIG. 5 is a diagram referenced to explain the effect of the maximum output power
of the charger on the charging procedure using the multi-stage constant-current charging
protocol.
FIG. 6 is a flowchart exemplarily illustrating a battery charging time prediction
11
method according to the first embodiment of the present disclosure.
FIG. 7 is a flowchart illustrating the subroutines of step S630 shown in FIG. 6.
FIG. 8 is a flowchart illustrating the subroutines of step S750 shown in FIG. 7.
FIG. 9 is a schematic diagram referenced to explain the first and second thermal
5 models used to predict the temperature change amount for each SOC section according to
the multi-stage constant-current charging protocol.
FIG. 10 is a flowchart exemplarily illustrating a battery charging time prediction
method according to the second embodiment of the present disclosure.
FIG. 11 is a flowchart exemplarily illustrating a battery charging time prediction
10 method according to the third embodiment of the present disclosure.
BEST MODE
Hereinafter, preferred embodiments of the present disclosure will be described in
detail with reference to the accompanying drawings. Prior to the description, it should be
15 understood that the terms used in the specification and the appended claims should not be
construed as limited to general and dictionary meanings, but interpreted based on the
meanings and concepts corresponding to technical aspects of the present disclosure on the
basis of the principle that the inventor is allowed to define terms appropriately for the best
explanation.
20 Therefore, the description proposed herein is just a preferable example for the
purpose of illustrations only, not intended to limit the scope of the disclosure, so it should
be understood that other equivalents and modifications could be made thereto without
departing from the scope of the disclosure.
12
The terms including the ordinal number such as “first”, “second” and the like, may
be used to distinguish one element from another among various elements, but not intended
to limit the elements by the terms.
Throughout the specification, when a portion is referred to as “comprising” or
5 “including” any element, it means that the portion may include other elements further,
without excluding other elements, unless specifically stated otherwise. Additionally,
terms such as “… unit” described in the specification refer to a unit that processes at least
one function or operation, and may be implemented as hardware, software, or a
combination of hardware and software.
10 In addition, throughout the specification, when a portion is referred to as being
“connected” to another portion, it is not limited to the case that they are “directly
connected”, but it also includes the case where they are “indirectly connected” with
another element being interposed between them.
FIG. 1 is a drawing illustrating the configuration of an electric vehicle according to
15 the present disclosure.
Referring to FIG. 1, the electric vehicle 1 includes a vehicle controller 2, a battery
pack 10, a relay 20, an inverter 30, and an electric motor 40. The charging and
discharging terminals P+, P- of the battery pack 10 can be electrically connected to the
charger 3 through a charging cable, etc. The charger 3 may be included in the electric
20 vehicle 1 or may be provided at the charging station.
The vehicle controller 2 (e.g., ECU: Electronic Control Unit) is configured to
transmit a key-on signal to the battery management system 100 in response to the start
button (not shown) provided in the electric vehicle 1 being switched to the ON position by
13
the user. The vehicle controller 2 is configured to transmit a key-off signal to the battery
management system 100 in response to the start button being switched to the OFF position
by the user. The charger 3 can communicate with the vehicle controller 2 and supply
constant-current or constant-voltage charging power through the charging and discharging
5 terminals P+, P- of the battery pack 10.
The battery pack 10 includes a battery 11 and a battery management system 100.
The battery 11 includes a cell group 12 and a case 13. The case 13 defines the
overall appearance of the battery 11 and provides an inner space where the cell group 12
can be placed. The case 13 is fixed to the battery room provided in the electric vehicle 1
10 using bolts, etc.
The cell group 12 is disposed (stored) in the inner space provided from the case 13
and includes at least one battery cell BC. The type of battery cell BC is not particularly
limited as long as it can be repeatedly charged and discharged, for example, a lithium-ion
cell.
15 When the cell group 12 includes a plurality of battery cells, these plurality of
battery cells may be connected in series, in parallel, or in a mixture of series and parallel.
The relay 20 is electrically connected in series to the battery 11 through a power
path that connects the battery 11 and the inverter 30. In FIG. 1, the relay 20 is illustrated
as connected between the positive terminal of the battery 11 and the charging and
20 discharging terminals P+. The relay 20 is controlled to turn on and off in response to a
switching signal from the battery management system 100. The relay 20 may be a
mechanical contactor turned on and off by the magnetic force of the coil, or a
semiconductor switch such as a MOSFET (Metal Oxide Semiconductor Field Effect
14
transistor).
The inverter 30 is provided to convert DC current from the cell group 12 into AC
current in response to commands from the battery management system 100 or the vehicle
controller 2.
5 The electric motor 40 is driven using AC power from the inverter 30. As the
electric motor 40, for example, a 3-phase AC motor 40 can be used.
The battery management system 100 includes a voltage sensor 111, a current
sensor 113, a battery temperature sensor 115, and a control unit 130. The battery
management system 100 may further include an outdoor air temperature sensor 117. The
10 battery management system 100 may further include a communication circuit 150.
The voltage sensor 111 is connected in parallel to the battery 11, and is configured
to detect the battery voltage, which is the voltage across both ends of the battery 11, and
generate a voltage signal representing the detected battery voltage.
The current sensor 113 is connected in series to the battery 11 through the current
15 path between the battery 11 and the inverter 30. The current sensor 113 is configured to
detect battery current, which is the current flowing through the battery 11, and generate a
current signal representing the detected battery current. The current sensor 113 may be
implemented with one of known current detection elements such as a shunt resistor and a
Hall effect element, or a combination of two or more of them.
20 The battery temperature sensor 115 is configured to detect battery temperature and
generate a temperature signal representing the detected battery temperature. The battery
temperature sensor 115 may be placed in the case 13 to detect a temperature close to the
actual temperature of the battery 11. For example, the battery temperature sensor 115
15
may be attached to the surface of at least one battery cell BC included in the cell group 12,
and may detect the surface temperature of the battery cell BC as the battery temperature.
The voltage sensor 111, the current sensor 113, and the battery temperature sensor
115 may be referred to as a ‘sensing unit’.
5 The outdoor air temperature sensor 117 is configured to detect outdoor air
temperature (atmosphere temperature), which is the temperature at a predetermined
location spaced apart from the battery 11, and generate a temperature signal representing
the detected outdoor air temperature. The outdoor air temperature sensor 117 may be
placed at a predetermined location outside the case 13 where heat exchange occurs
10 between the battery 11 and the outdoor air.
Each of the battery temperature sensor 115 and the outdoor air temperature sensor
117 may be implemented with one of known temperature detection elements such as
thermocouples, thermistors, and bimetals, or a combination of two or more of them.
The communication circuit 150 is configured to support wired or wireless
15 communication between the control unit 130 and the vehicle controller 2. Wired
communication may be, for example, CAN (Controller Area Network) communication,
and wireless communication may be, for example, ZigBee or Bluetooth communication.
Of course, the type of communication protocol is not particularly limited as long as it
supports wired and wireless communication between the control unit 130 and the vehicle
20 controller 2. The communication circuit 150 may include an output device (e.g., display,
speaker) that provides information received from the control unit 130 and/or the vehicle
controller 2 in a form recognizable to the user.
The control unit 130 is operably coupled to the relay 20, the voltage sensor 111,
16
the current sensor 113, the battery temperature sensor 115, the outdoor air temperature
sensor 117, and the communication circuit 150. The operational combination of two
components means that the two components are connected directly or indirectly to enable
transmission and reception of signals in one direction or both directions.
5 The control unit 130 may collect a voltage signal from the voltage sensor 111, a
current signal from the current sensor 113, a temperature signal from the battery
temperature sensor 115 (can be referred to as a ‘battery temperature signal’), and/or a
temperature signal from the outdoor air temperature sensor 117 (can be referred to as an
‘outdoor air temperature signal’). The control unit 130 may convert and record each
10 analog signal collected from the sensors 111, 113, 115, 117 into digital values using an
ADC (Analog to Digital Converter) provided therein.
The control unit 130 may be referred to as a ‘control circuit’ or a ‘battery
controller’, and in terms of hardware, it may be implemented using at least one of ASICs
(application specific integrated circuits), DSPs (digital signal processors), DSPDs (digital
15 signal processing devices), PLDs (programmable logic devices), FPGAs (field
programmable gate arrays), microprocessors, and other electrical units to perform
functions.
The memory 140 may include at least one type of storage medium selected from,
for example, flash memory type, hard disk type, SSD (Solid State Disk) type, SDD (Silicon
20 Disk Drive) type, multimedia card micro type, RAM (random access memory), SRAM
(static random access memory), ROM (read-only memory), EEPROM (electrically
erasable programmable read-only memory), or PROM (programmable read-only memory).
The memory 140 can store data and programs required for calculation operations by the
17
control unit 130. The memory 140 can store data representing the result of an operation
performed by the control unit 130. In FIG. 1, the memory 140 is shown as being
physically independent from the control unit 130, but it may also be built in the control
unit 130.
5 The memory 140 may store at least one reference charging map associated with
the multi-stage constant-current charging protocol for the battery 11. Each reference
charging map will be described in more detail below.
The control unit 130 may turn on the relay 20 in response to the key-on signal.
The control unit 130 may turn off the relay 20 in response to the key-off signal. The key10 off signal indicates a transition from a use state to an idle state. Alternatively, the vehicle
controller 2 may be responsible for on-off control of the relay 20 instead of the control unit
130.
While the relay 20 is turned on, the battery 11 is in use. Conversely, while the
relay 20 is turned off, the battery 11 is in an idle state. The use state is a state in which
15 the battery 11 is being charged and discharged, and can also be referred to as a ‘cycle state’.
The idle state is a state in which charging and discharging of the battery 11 is stopped, and
can also be called a ‘calendar state’.
While the battery 11 is in use, the control unit 130 may determine a voltage
detection value, a current detection value, a battery temperature detection value, and an
20 outdoor air temperature detection value based on the voltage signal, the current signal, the
battery temperature signal, and the outdoor air temperature signal, and then determine
(estimate) the state of charge (SOC) of the battery 11 based on the voltage detection value,
the current detection value, and/or the battery temperature detection value. SOC is the
18
ratio of the remaining capacity to the fully charged capacity (maximum capacity) of the
battery 11, and is usually processed in the range of 0 to 1 or 0% to 100%. To determine
SOC, known methods such as ampere counting, OCV (Open Circuit Voltage)-SOC curve,
and/or Kalman filter can be used. For reference, in this specification, simple description
5 ‘temperature detection value’ may refer to a battery temperature detection value.
The maximum capacity of the battery 11 can be estimated using any one of various
known methods or a combination two or more of them. As an example, the control unit
130 may calculate the current maximum capacity of the battery 11 by dividing the
accumulated current amount over the period from when the SOC of the battery 11 is at the
10 first value to when the SOC of the battery 11 reaches the second value by the change
amount of SOC (i.e., the difference between the first value and the second value).
Alternatively, the control unit 130 may determine the maximum capacity of the battery 11
by multiplying the SOH (State Of Health) calculated through any one of various known
methods or a combination of two or more of them by a predetermined design capacity
15 (maximum capacity of a new battery).
FIGS. 2 to 4 are diagrams referenced to explain an exemplary reference charging
map used in a charging procedure using a multi-stage constant-current charging protocol.
A plurality of reference charging maps (CM1 to CMN) may be stored in the
memory 140. The plurality of reference charging maps can be one-to-one related to the
20 plurality of temperature sections (CM1 to CMN, N is a natural number greater than or equal
to 2).
FIGS. 2 to 4 show a reference charging map (CMn, where n is a natural number
less than or equal to N) among the plurality of reference charging maps (CM1 to CMN)
19
associated with any one (e.g., 10℃ or more and less than 25°C) among a plurality of
temperature sections (e.g., less than 0℃, 0℃ or more and less than 10℃, 10℃ or more
and less than 25℃, 25℃ or more and less than 40℃, 40℃ or more).
Specifically, the graph shown in FIG. 2 illustrates the reference current profile 200,
5 which represents the change in charging current for SOC over the entire SOC range. In
the present disclosure, the entire SOC range is partitioned into first to Mth SOC sections
(Z[1] to Z[M], where M is a natural number greater than or equal to 2). For convenience
of explanation, M = 4 is illustrated in FIGS. 2 to 4.
In the first to Mth SOC sections (Z[1] to Z[M]), the start point of the first SOC
10 section (Z[1]) is the same as the start point of the entire SOC range (e.g., SOC 0%), and the
end point of the Mth SOC section (Z[M]) is the same as the end point of the entire SOC
range (e.g., SOC 100%). The end point of the entire SOC range can be set in advance as
the target SOC.
Among two adjacent sections of the first to Mth SOC sections (Z[1] to Z[M]), the
15 end point of the preceding section may match the start point of the following section. For
example, the end point (e.g., 50%) of the first SOC section (Z[1]) matches the start point
(e.g., 50%) of the second SOC section (Z[2]).
In FIG. 2, the first to Mth SOC sections (Z[1] to Z[M]) are one-to-one related to
the first to Mth reference current values (I#1 to I#M), and each reference current value
20 represents the charging current for constant-current charging in the SOC section associated
therewith. According to the reference current profile 200, the reference current value for
a specific SOC section is single, which indicates that the reference current value is for
constant-current charging in the SOC section associated therewith. In other words, if the
20
charger 3 can supply sufficiently large output power, the battery 11 can be constant-current
charged by the charging current according to the reference current profile 200.
In the multi-stage constant-current charging protocol, the charging current may
need to be reduced as SOC increases to protect the battery. Referring to FIG. 2, the first
5 to fourth reference current values (I#1 to I#4) can be predetermined to decrease step by
step, for example, to 8 [A], 6 [A], 4 [A], and 2 [A], as SOC increases.
The graph shown in FIG. 3 illustrates the reference voltage profile 300, which
represents the change in battery voltage for SOC over the entire SOC range. The
reference voltage profile 300 may be obtained in advance from the result of repeatedly
10 performing a charging test that periodically measures the voltage of each sample battery
while charging at least one sample battery with the same specifications as the battery 11
according to the reference current profile 200. The reference voltage profile 300 can be
recorded in the memory 140 as a time series or multi-order function of the battery voltage
for the SOC.
15 The graph shown in FIG. 4 illustrates the reference power profile 400, which
represents the change in charging power for SOC over the entire SOC range. The
reference power profile 400 may be obtained in advance from the result of repeatedly
performing a charging test that periodically measures the charging power supplied to each
sample battery while charging at least one sample battery with the same specifications as
20 the battery 11 according to the reference current profile 200. The reference power profile
400 may be recorded in the memory 140 as a time series or multi-order function of the
charging power for the SOC.
The reference power profile 400 is practically equal to the product of the reference
21
current profile 200 and the reference voltage profile 300 in the entire SOC range. That is,
the charging power on the reference power profile 400 in a specific SOC is equal to the
product of the voltage value on the reference voltage profile 300 and the current value on
the reference current profile 200 in that specific SOC. Note that in each SOC section, the
5 voltage of the battery 11 increases while the reference current value is constant, so the
charging power gradually increases. A portion of the reference power profile 400, which
represents the power change in a specific SOC section, will hereinafter be referred to as the
‘reference power curve’. That is, the reference power profile 400 includes the successive
first to fourth reference power curves (P#1 to P#4). For reference, in the reference
10 current profile 200 shown in FIG. 2, the transition of the reference current value occurs at
the boundary of two SOC sections, so among the first to fourth reference power curves
(P#1 to P#4) shown in FIG. 4, it is shown that there is a deviation in charging power at
each boundary of two adjacent reference power curves (e.g., P#2 and P#3).
Meanwhile, the reference charging map (CMn) associated with a specific
15 temperature section may include the reference current profile 200, the reference voltage
profile 300, and the reference power profile 400, which are obtained in advance through
testing in the same temperature section.
Relatedly, to record the reference current profile 200, the reference voltage profile
300, and the reference power profile 400 all in the memory 140, a fairly large storage space
20 is required. Additionally, it is possible to calculate (generate) the reference voltage
profile (300, see FIG. 3) through the process of dividing the reference power profile (400,
see FIG. 4) by the reference current profile (200, see FIG. 2). Therefore, at least one of
the plurality of reference charging maps (CM1 to CMN) can be designed to include only the
22
reference current profile 200 and the reference power profile 400.
To summarize the above, at least one reference charging map among the plurality
of reference charging maps (CM1 to CMN) includes the first to Mth reference power curves
(P#1 to P#M) and the first to Mth reference current values (I#1 to I#M) that are one-to-one
associated with the first to Mth 5 SOC sections (Z[1] to Z[M]).
In the same SOC section, the reference power curve of a reference charging map
associated with one temperature section (e.g., 0°C or more and less than 10°C) may be
different from a reference power curve of another reference charging map associated with
another temperature section (e.g., 10°C or more and less than 25°C).
10 Likewise, in the same SOC section, the reference current value recorded in the
reference charging map associated with one temperature section (e.g., 0°C or more and less
than 10°C) may be different from the reference current value recorded in another reference
charging map associated with another temperature section (e.g., 10°C or more and less than
25°C).
15 The relationship between charging current, battery voltage, and charging power
with respect to the SOC and temperature of the battery 11 depends on the size, weight,
active material, and appearance of the battery 11. Therefore, FIGS. 2 to 4 should be
understood as a simple example in explaining the present disclosure.
For reference, the upper limit of the entire SOC range (i.e. target SOC) may be set
20 to a value less than 100% (e.g. 98%). In this case, from the time the SOC of the battery
11 reaches the target SOC until it is fully charged, the battery 11 can be charged using the
constant-voltage charging mode instead of the constant-current charging mode or constantpower charging mode.
23
Assume that m is a natural number less than or equal to M. In this specification,
m is used as the section index of the SOC section to which the current SOC of the battery
11 belongs. Then, the symbol P#m used in this specification may represent the reference
power curve associated with the SOC section (Z[m]) among the first to Mth reference
5 power curves (P#1 to P#M) recorded in the reference charging map (CMn) associated with
the temperature section to which the battery temperature (detection value or predicted
value) belongs. Additionally, the symbol I#m may represent the reference current value
associated with the SOC section (Z[m]). Each reference current value (e.g., I#1) may be
a predetermined value that represents the maximum charging current allowed for charging
10 the battery 11 without irreversible damage from the start point (e.g., 0 %) to the end point
(e.g., 50 %) of the SOC section (e.g., Z[1]) associated therewith.
When x is a natural number of M or less, the size (width) of the SOC section
(Z[x]) is the difference between the start point and the end point of the SOC section (Z[x]),
and the sign ΔZ[x] used. In FIGS. 2 to 4, the sizes of the first to fourth SOC sections
15 (Z[1] to Z[4]) are illustrated as 50%, 20%, 15%, and 15% in that order. Of course, it
should be understood that the first to Mth SOC sections (Z[1] to Z[M]) may have the same
size or be determined differently from FIG. 2.
FIG. 5 is a diagram referenced to explain the effect of the maximum output power
of the charger on the charging procedure using the multi-stage constant-current charging
20 protocol.
FIG. 5 shows three horizontal lines 510, 520, 530 along with the reference power
profile 400 of FIG. 4. Any one of these three horizontal lines 510, 520, 530 represents
the maximum output power (PMAX) that can be supplied from the charger 3 to the battery
24
11. The control unit 130 may identify the maximum output power (PMAX) of the charger
3 from the vehicle controller 2 and/or the charger 3 through the communication circuit 150.
In any of the constant-current charging mode, the constant-power charging mode,
and the constant-voltage charging mode, the voltage of the battery 11 gradually increases
5 during charging by the corresponding charging mode in each SOC section.
The horizontal line 510 illustrates that the maximum output power (PMAX) that can
be supplied from the charger 3 to the battery 11 is greater than or equal to the maximum
charging power required for the entire SOC section. In FIG. 5, it is shown that the
maximum charging power is required at the end point of the SOC section (Z[1]). In this
10 case, only the constant-current charging mode in which different charging currents (I#1 to
I#M) are sequentially switched according to the multi-stage constant-current charging
protocol will be implemented. In other words, in the SOC section (Z[x]), the battery 11 is
charged constant-currently with the charging current of the reference current value (I[x]),
so the temporal change in the charging power supplied to the battery 11 can be treated as
15 matching the reference power profile 400.
The horizontal line 520 illustrates that the maximum output power (PMAX) of the
charger 3 is less than or equal to the minimum charging power required for the entire SOC
section. In FIG. 5, it is shown that the minimum charging power is required at the start
point of the SOC section (Z[1]). In this case, the charging power supplied to the battery
20 11 over the entire SOC section is limited to the maximum output power (PMAX) of the
charger 3. In other words, instead of sequentially switching different charging currents
according to the multi-stage constant-current charging protocol, only the constant-power
charging mode based on the maximum output power (PMAX) will be implemented until
25
reaching the end point from the start point of the entire SOC section.
The horizontal line 530 illustrates a situation where the maximum output power
(PMAX) of the charger 3 is greater than the minimum charging power required for the entire
SOC section and less than the maximum charging power.
5 Looking at the horizontal line 530, the maximum output power (PMAX) is located
on the upper side of the reference power curve (P#1) at the beginning of the SOC section
(Z[1]), and then is located below the reference power curve (P#1) from a specific SOC
(ZX). In other words, there is an intersection point (X) between the horizontal line 530
and the reference power curve (P#1) within the SOC section (Z[1]). This intersection
10 point (X) is a transition point from the constant-current charging mode by the reference
current value (I#1) to the constant-power charging mode by the maximum output power
(PMAX).
Additionally, in the SOC section (Z[2]), the maximum output power (PMAX) is
below the reference power curve (P#1), while in the SOC section (Z[3]) and the SOC
15 section (Z[4]), the maximum output power (PMAX) is above the reference power curve
(P#3) and the reference power curve (P#4). Therefore, in the SOC section (Z[2]), the
battery 11 is charged in the constant-power charging mode by the maximum output power
(PMAX), and in the SOC section (Z[3]) and the SOC section (Z[4]), the battery 11 is
charged in the constant-current charging mode according to the reference current value
20 (I#3) and the reference current value (I#4).
Conventionally, there was no way to reflect the fact that the charging power
supplied to the battery 11 during charging is limited to the maximum output power (PMAX)
of the charger 3 to the process of predicting the remaining charging time. For example,
26
even if the maximum output power (PMAX) of the charger 3 is equal to the horizontal line
530 shown in FIG. 5, in predicting the remaining charging time in each of the two SOC
sections (Z[1], Z[2]), assuming that the charging power is supplied according to the
reference power curves (P#1, P#2), the prediction error of the remaining charging time is
5 accumulated by the power difference between the charging power according to the
reference power curves (P#1, P#2) in the latter half (ZX to 50%) of the SOC section (Z[1])
and the entire SOC section (Z[2]) and the maximum output power (PMAX) of the charger 3.
As a result, situations where the predicted value of the remaining charging time for the two
SOC sections (Z[1], Z[2]) as well as the total remaining charging time until reaching the
10 target SOC is significantly different from the actual value frequently occur.
Therefore, in order to reduce the prediction error of the remaining charging time
for each SOC section, by comparing the charging power according to the reference power
profile 400 with the maximum output power (PMAX) of the charger 3 for each SOC section,
it is necessary to determine whether to implement any one of the constant-current charging
15 mode and the constant-power charging mode or to implement both of them, and then
calculate (predict) the remaining charging time for each SOC section using the
characteristics of the determined charging mode.
FIG. 6 is a flowchart exemplarily illustrating a battery charging time prediction
method according to the first embodiment of the present disclosure, FIG. 7 is a flowchart
20 illustrating the subroutines of step S630 shown in FIG. 6, and FIG. 8 is a flowchart
illustrating the subroutines of step S750 shown in FIG. 7. The method of FIG. 6 may be
executed by the battery management system 100 at every set time while charging the
battery 11 using the multi-stage constant-current charging protocol.
27
Referring to FIGS. 1 to 6, in step S610, the control unit 130 determines the
estimated SOC value of the battery 11 based on the voltage detection value and the current
detection value of the battery 11. The battery temperature detection value can be
additionally used to determine the estimated SOC value. The voltage detection value, the
5 current detection value, the temperature detection value, and the estimated SOC value in
step S610 may represent current voltage, current, temperature, and SOC of the battery 11,
respectively. The control unit 130 records the voltage detection value, the current
detection value, the temperature detection value, and the estimated SOC value determined
at each setting time in the memory 140. In step S610, the outdoor air temperature
10 detection value (TATM, see FIG. 9) indicating the current outdoor air temperature may be
additionally determined.
In step S620, the control unit 130 obtains the mth reference current value (I#m) and
the mth reference power curve (P#m) associated with the SOC section (Z[m], where m is a
natural number less than or equal to M) to which the estimated SOC value determined in
15 step S610 belongs from the reference charging map (CMn) associated with the temperature
section to which the temperature detection value belongs among the plurality of reference
charging maps (CM1 to CMN). In this specification, the mth SOC section (Z[m]) may
refer to the SOC section to which the current SOC of the battery 11 belongs.
In step S630, the control unit 130 determines the mth predicted charging time value,
20 which represents the time required for the SOC of the battery 11 to reach the end point of
the mth SOC section (Z[m]) from the estimated SOC value determined in step S610, based
on the estimated SOC value and the end point of the mth SOC section (Z[m]), and further
based on at least one of the mth reference current value (I#m), the maximum output power
28
(PMAX), and the mth reference power curve (P#m), according to the comparison result of the
maximum output power (PMAX) and the mth reference power curve (P#m). For example,
if the estimated SOC value determined in step S610 is 2%, the mth SOC section (Z[m]) =
Z[1], and the mth predicted charging time value (first predicted charging time value) may
5 be the time required for the SOC of the battery 11 to reach 50% from 2%. Step S630
includes step S710 to step S750 as its subroutines.
Referring to FIG. 7, in step S710, the control unit 130 determines whether the
maximum output power (PMAX) of the charger 3 is greater than or equal to the maximum
power value of the mth reference power curve (P#m). For example, if the horizontal line
10 510 in FIG. 5 indicates the maximum output power (PMAX), the value of step S710 is
“Yes.” On the other hand, if the horizontal line 520 or the horizontal line 530 in FIG. 5
indicates the maximum output power (PMAX), the value of step S710 is “No”. If the value
of step S710 is “Yes,” the process proceeds to step S720. If the value of step S710 is
“No”, the process proceeds to step S730.
In step S720, the control unit 130 determines the mth 15 predicted charging time value
based on the estimated SOC value, the end point of the mth SOC section (Z[m]), and the
mth reference current value (I#m). The SOC difference (ΔZ[m]) is a value obtained by
subtracting the estimated SOC value from the end point of the mth SOC section (Z[m]).
The mth predicted charging time value determined through step S720 may represent the
20 charging time by the constant-current charging mode. The control unit 130 may
determine the mth predicted charging time value by calculating the required charging
capacity corresponding to the SOC difference (ΔZ[m]) and then dividing the calculated
required charging capacity by the mth reference current value (I#m).
29
Equation 1 below is an example of a function that can be used to determine
charging time by the constant-current charging mode.

5 In Equation 1, z = SOC, zf = SOC to be reached through charging, zi = SOC at a
specific point before reaching zf, ICHG = charging current, QMAX = maximum capacity of
the battery 11, ΔQ = capacity required for charging = Δz = capacity corresponding to (zf -
zi), and ΔtCC = charging time. For reference, Equation 1 is expressed using three equal
signs to aid understanding, but it can be stored in the memory 140 to include only the
10 rightmost term among the three terms on the right.
As an example, assume QMAX = 10000 mAh, zf - zi = end point of the mth SOC
section (Z[m]) - estimated SOC value = 50% - 2% = ΔZ[m] = 48%, and I#m = 10 A.
Then, since ΔQ = 4800 mAh, Δt#m = 4800 mAh/10 A = 0.48 hours.
In step S730, the control unit 130 determines whether the maximum output power
(PMAX) of the charger 3 is less than or equal to the minimum power value of the mth 15
reference power curve (P#m). For example, if the horizontal line 520 in FIG. 5 indicates
the maximum output power (PMAX), the value of step S730 is “Yes.” On the other hand,
if the horizontal line 530 in FIG. 5 indicates the maximum output power (PMAX), the value
of step S730 is “No”. If the value of step S730 is “Yes,” the process proceeds to step
20 S740. The value of step S730 being “No” means that the maximum output power (PMAX)
of the charger 3 is between the minimum power value and the maximum power value of
the mth reference power curve (P#m). If the value of step S730 is “No”, the process
proceeds to step S750.
30
In step S740, the control unit 130 determines the mth predicted charging time value
based on the estimated SOC value, the end point of the mth SOC section (Z[m]), the
maximum output power (PMAX), and the mth reference power curve (P#m). The mth
predicted charging time value determined through step S740 may be the charging time by
5 the constant-power charging mode. Equation 2 below is an example of a function that
can be used to determine the charging time by the constant-power charging mode.

In Equation 2, z = SOC, zf = SOC to be reached through charging, zi = SOC at a
10 specific point before reaching zf, ICHG = charging current, V(z) = voltage estimate value of
the battery 11 at z during constant-current charging with ICHG, VAV = average of V(z) in the
range of zi to zf. PCHG(z) = charging power at z during constant-current charging with ICHG,
PCP = charging power actually supplied (constant power), ΔWhCP = required charging
energy, ΔQ = required charging capacity, and ΔtCP = charging time. For reference, the
15 unit of ΔWhCP may be Wh (Watt-hour). For reference, Equation 2 is expressed using four
equal signs to aid understanding, but it can be stored in the memory 140 to include only the
rightmost term among the four terms on the right.
Assume that the maximum capacity of the battery 11 = 10000 mAh, the estimated
SOC value is 2%, and the maximum output power (PMAX) matches the horizontal line 520
20 in FIG. 5. Then, in Equation 2, zi = 2%, zf = 50%, zf - zi = ΔZ[1] = 48%, Q = 4800 mAh,
31
ICHG = I#1 = 10 A, and PCHG (z) = P#1. If VAV = 3.3 V and PCP = PMAX = 20 W (Watt),
ΔtCP = {4800 mAh × 3.3 V} /20 W = 0.792 hour = Δt#1.
In step S750, the control unit 130 determines the mth predicted charging time value
(Δt#m) based on the estimated SOC value, the end point of the mth SOC section (Z[m]), the
mth reference current value (I#m), the maximum output power (PMAX), and the mth 5
reference power curve (P#m).
Step S750 includes step S810 to step S850 as its subroutines.
Referring to FIG. 8, in step S810, the control unit 130 determines the intersection
SOC, which represents the SOC at the intersection point of the mth reference power curve
10 (P#m) and the maximum output power (PMAX). Referring to FIG. 5, when the maximum
output power (PMAX) matches the horizontal line 530, X represents the intersection point
and ZX represents the intersection SOC.
In step S820, the control unit 130 determines whether the intersection SOC (ZX) is
greater than the estimated SOC value (current SOC). If the value of step S820 is “Yes,”
15 the process proceeds to step S830 and step S840. The value of step S820 being “No”
means that only the constant-power charging mode, in which the charging power is limited
to maximum output power (PMAX), will be implemented from now until the end point of
the mth SOC section (Z[m]). If the value of step S820 is “No”, the process may proceed
to step S740 of FIG. 7.
In step S830, the control unit 130 determines the mth 20 predicted constant-current
charging time value, which represents the time required for the SOC of the battery 11 to
reach the intersection SOC (ZX) from the estimated SOC value, based on the estimated
SOC value, the intersection SOC (ZX), and the mth reference current value (I#m).
32
Equation 1 described above can be used to determine the mth predicted constant-current
charging time value. In other words, assuming that the current SOC is 2%, ΔtCC when the
intersection SOC (ZX) is entered instead of 50% of the end point of the first SOC section
(Z[1]) as zf in Equation 1 is determined as the mth predicted constant-current charging time
5 value.
In step S840, the control unit 130 determines the mth predicted constant-power
charging time value, which represents the time required for the SOC of the battery 11 to
reach the end point of the mth SOC section (Z[m]) from the intersection SOC (ZX), based
on the intersection SOC (ZX), the end point of the mth SOC section (Z[m]), the maximum
output power (PMAX), and the mth 10 reference power curve (P#m).
Equation 2 described above can be used to determine the mth predicted constantpower charging time value. In other words, when ZX > 2% = current SOC, ΔtCP when the
intersection SOC (ZX) is input instead of the estimated SOC value as zi in Equation 2 is
determined as the mth predicted constant-power charging time value.
In step S850, the control unit 130 determines the mth 15 predicted charging time value
to be equal to the sum of the mth predicted constant-current charging time value determined
in step S830 and the mth predicted constant-power charging time value determined in step
S840.
Step S640 described from now on can be executed on the condition that m is less
20 than M. The fact that m, which is the section index of the SOC section to which the
current SOC belongs, is less than M means that there is at least one SOC section following
the mth SOC section (Z[m]) in which the charging procedure is currently in progress. For
example, when m = 1 < 4 = M, since charging is scheduled in three SOC sections (Z[2] to
33
Z[4]), step S640 may be performed.
In step S640, the control unit 130 determines the predicted temperature value at
the start point of the (m+1)
th SOC section (Z[m+1]), based on the battery temperature
detection value and the mth predicted charging time value (Δt#m), and further based on at
least one of the mth 5 reference current value (I#m) and the maximum output power (PMAX).
The predicted temperature value at the start point of the (m+1)
th SOC section (Z[m+1])
represents the temperature of the battery 11 at the end point of the mth SOC section (Z[m]).
If the outdoor air temperature detection value (TATM) is additionally obtained in step S610,
in step S640, further based on the outdoor air temperature detection value (TATM), the
predicted temperature value at the start point of the (m+1)
th 10 SOC section (Z[m+1]) can be
determined.
Step S640 may include step S642 and step S644.
In step S642, the control unit 130 determines the predicted temperature change
amount during the period from the estimated SOC value representing the current SOC of
the battery 11 until reaching the start point of the (m+1)
th 15 SOC section (Z[m+1]). At least
one of the first thermal model and the second thermal model described later may be used to
determine the predicted temperature change amount.
In step S644, the control unit 130 determines the predicted temperature value at
the start point of the (m+1)
th SOC section (Z[m+1]) to be the same as the sum of the
20 predicted temperature change amount (e.g., ΔTCC, ΔTCP, or ΔTCC+ΔTCP in FIG. 9)
determined in step S642 and the temperature detection value obtained in step S610.
FIG. 9 is a schematic diagram referenced to explain the first and second thermal
models used to predict the temperature change amount for each SOC section according to
34
the multi-stage constant-current charging protocol.
In FIG. 9, TBAT is the battery temperature (detection value or predicted value), Δt
is the charging time, ICC is the constant current, PCP is the maximum output power (PMAX)
of the charger 3, and TATM is the outdoor air temperature detection value.
5 The control unit 130 may calculate the predicted temperature change amount
indicating the temperature change amount until the SOC of the battery 11 within a specific
SOC section reaches the end point of the corresponding SOC section, using at least one of
the first thermal model and the second thermal model.
The first thermal model may use Equation 3 illustrated below as the first thermal
10 model as a predetermined function to output the temperature change amount (ΔTCC) by the
constant-current charging mode in response to the values of the input variables (TBAT, Δt,
ICC, TATM) assigned by the control unit 130.

15 In Equation 3, α represents the adjustment coefficient (predetermined), β
represents the heat exchange coefficient (predetermined), and CH represents the heat
capacity of the battery 11 (predetermined). For the first thermal model, TATM may be a
predetermined value (e.g., 25°C) instead of the outdoor air temperature detection value.
Equation 3 is just an example of the first thermal model, and the first thermal
20 model is not limited to Equation 3 above. In other words, if a positive correlation is given
between each of the input variables ICC, Δt, and the difference between TATM and TBAT, and
the output variable ΔTCC, in accordance with the heat generation characteristics of the
35
battery 11 in the constant-current charging mode, a function or algorithm other than
Equation 3 can be used as the first thermal model.
The second thermal model may use Equation 4 illustrated below as the second
thermal model as a predetermined function to output the temperature change amount
5 (ΔTCP) by the constant-power charging mode in response to the values of the input
variables (TBAT, Δt, PCP, TATM) assigned by the control unit 130.

In Equation 4, γ is the adjustment coefficient (predetermined), and the remaining
10 variables and coefficients are the same as in Equation 3.
Equation 4 is only an example of the second thermal model, and the second
thermal model is not limited to Equation 4 above. In other words, if a positive correlation
is given between each of the input variables PCP, Δt, and the difference between TATM and
TBAT, and the output variable ΔTCP, in accordance with the heat generation characteristics
15 of the battery 11 in the constant-power charging mode, a function or algorithm other than
Equation 4 can be used as the second thermal model.
Referring to FIGS. 5 and 9 together, when the estimated SOC value (Zest) is less
than intersection SOC (ZX), the sum of ΔTCC output when inputting the mth predicted
constant-current charging time value into Δt in Equation 3 and ΔTCP output when inputting
the mth 20 predicted constant-power charging time value into Δt in Equation 4 can be
determined as the predicted temperature change amount in the SOC section (Z[1]). If the
estimated SOC value (Zest) is greater than or equal to the intersection SOC (ZX), ΔTCP in
36
Equation 4 can be determined as the predicted temperature change amount in the SOC
section (Z[1]). Additionally, the predicted temperature change amount in the SOC
section (Z[2]) can be determined by Equation 4. The predicted temperature change
amount in each of the remaining two SOC sections (Z[3], Z[4]) can be determined by
5 Equation 3.
Referring back to FIG. 7, step S720, step S740, and step S750 are performed
alternatively.
When step S720 is executed, the control unit 130 may determine the predicted
temperature value at the start point of the (m+1)
th SOC section (Z[m+1]) by assigning the
battery temperature detection value, the mth predicted charging time value, and the mth 10
reference current value (I#m) to the input variables (TBAT, Δt, ICC) of the first thermal
model, respectively, and adding the temperature detection value to the temperature change
amount (ΔTCC) output from the first thermal model.
When step S740 is executed, the control unit 130 may determine the predicted
temperature value at the start point of the (m+1)
th 15 SOC section (Z[m+1]) by assigning the
battery temperature detection value, the mth predicted charging time value, and the
maximum output power (PMAX) to the input variables (TBAT, Δt, PCP) of the second thermal
model, respectively, and adding the temperature detection value to the temperature change
amount (ΔTCP) output from the second thermal model.
20 When step S750 is executed, the control unit 130 may determine the predicted
temperature value in the intersection SOC (ZX) by assigning the battery temperature
detection value, the mth predicted constant-current charging time value (ΔtCC in Equation
1), and the mth reference current value (I#m) to the input variables (TBAT, Δt, ICC) of the
37
first thermal model, respectively, and adding the battery temperature detection value to the
temperature change amount (ΔTCC) output from the first thermal model. Subsequently,
the control unit 130 may determine the predicted temperature value at the start point of the
(m+1)
th SOC section (Z[m+1]) by assigning the battery temperature detection value, the
mth predicted constant-power charging time value (ΔtCP of Equation 2) and the mth 5
reference current value (I#m) in the intersection SOC (ZX) to the input variables (TBAT, Δt,
PCP) of the second thermal model, respectively, and adding the predicted temperature value
in the intersection SOC (ZX) to the temperature change amount (ΔTCP) output from the
second thermal model.
10 The operation of calculating the predicted temperature change amount for the SOC
section (Z[k], where k is a natural number greater than m and less than M) that follows the
current SOC section (Z[m]) is common to the operation of calculating the predicted
temperature change amount in the SOC section (Z[m]) described above, except that the
predicted battery temperature value at the start point of the following SOC section (Z[k]) is
15 assigned as TBAT in FIG. 9, and the reference current value (I#k) associated with the
following SOC section (Z[k]) is assigned as ICC in FIG. 9.
The predicted temperature value at the start point of the SOC section (Z[k]) is used
to specify one reference charging map (CMu, u is a natural number less than or equal to N)
among the plurality of reference charging maps (CM1 to CMN), and obtain the k
th reference
power curve (P#k) and the k
th 20 reference current value (I#k) from the specified reference
charging map (CMu).
The control unit 130 may perform the above-described process for each SOC
section until the predicted charging time value for the last SOC section (e.g., Z[M]) to
38
which the target SOC belongs is determined. Accordingly, the predicted charging time
value for each of the current SOC section (Z[m]) to the last SOC section (Z[M]) can be
sequentially determined. Therefore, by adding all the predicted charging time values
determined for the current SOC section (Z[m]) to the last SOC section (Z[M]), the total
5 remaining time required to reach the target SOC from the current SOC can be determined.
FIG. 10 is a flowchart exemplarily illustrating a battery charging time prediction
method according to the second embodiment of the present disclosure. The method of
FIG. 10 may be executed subsequent to the method of FIG. 5, on the condition that m is
less than M. If m is less than M, it means that among the first to Mth SOC sections (Z[1]
to Z[M]), there is at least one SOC section following the mth 10 SOC section (Z[m]) to which
the current SOC belongs.
Referring to FIGS. 1 to 10, in step S1010, the control unit 130 sets the section
index k equal to (m+1).
In step S1020, the control unit 130 determines whether the determination of the
predicted temperature value at the start point of the k
th 15 SOC section (Z[k]) has been
completed. If the value of step S1020 is “Yes,” the process proceeds to step S1030. If
the value of step S1020 is “No,” the process may wait until the value of step S1020
becomes “Yes.”
In step S1030, the control unit 130 determines the k
th reference power curve (P#k)
and the k
th reference current value (I#k) associated with the k
th 20 SOC section (Z[k]) from
any one reference charging map (CMu) among the plurality of reference charging maps
(CM1 to CMN) associated with one temperature section to which the predicted temperature
value at the start point of the k
th SOC section (Z[k]) belongs among the plurality of
39
temperature sections.
In step S1040, the control unit 130 determines the k
th predicted charging time
value representing the time required for the SOC of the battery 11 to reach the end point of
the k
th SOC section (Z[k]) from the start point of the k
th SOC section (Z[k]), based on the
size (ΔZ) of the k
th SOC section (Z[k]), and further based on at least one of the k
th 5
reference current value (I#k), the maximum output power (PMAX), and the k
th reference
power curve (P#k).
The operation of determining the k
th predicted charging time value is common
with the operation described above with reference to FIGS. 7 and 8, except that the section
10 index m is replaced by k, and the estimated SOC value is replaced by the start point of the
k
th SOC section (Z[k]).
In step S1050, the control unit 130 determines whether the section index k is equal
to M. M can be said to be the identification number of the last SOC section (Z[M]) to
which the target SOC belongs. The fact that the section index k is equal to M means that
15 the determination of the predicted charging time value for the last SOC section (Z[M]) has
been completed. If the value of step S1050 is “No”, the process proceeds to step S1060.
If the value of step S1050 is “Yes,” the process proceeds to step S1080.
In step S1060, the control unit 130 may determine the predicted temperature value
at the start point of the (k+1)
th SOC section (Z[k+1]), based on the predicted temperature
value and the k
th predicted charging time value at the start point of the k
th 20 SOC section
(Z[k]), and further based on at least one of the k
th reference current value (I#k) and the
maximum output power (PMAX).
Step S1060 may include step S1062 and step S1064.
40
In step S1062, the control unit 130 determines the predicted temperature change
amount for the period until the SOC of the battery 11 reaches the start point of the (k+1)
th
SOC section (Z[k+1]) from the start point of the k
th SOC section (Z[k]). At least one of
the above-described first thermal model and second thermal model may be used to
5 determine the predicted temperature change amount in the SOC section (Z[k]).
In step S1064, the control unit 130 determines the predicted temperature value at
the start point of the (k+1)
th SOC section (Z[k+1]) to be equal to the sum of the predicted
temperature change amount determined in step S1062 and the predicted temperature value
at the start point of the k
th SOC section (Z[k]).
10 In step S1070, the control unit 130 increases the section index k by 1 and then
returns to step S1030. That is, steps S1030 to S1070 can be repeated until k reaches M.
In step S1080, the control unit 130 determines the total remaining charging time
until the charging procedure using the multi-stage constant-current charging protocol is
terminated (i.e., until the SOC of the battery reaches the target SOC) by adding the mth to
Mth predicted charging time values. The mth to Mth 15 predicted charging time values
correspond one-to-one to the mth to Mth SOC sections (Z[m] to Z[M]).
FIG. 11 is a flowchart exemplarily illustrating a battery charging time prediction
method according to the third embodiment of the present disclosure. The method of FIG.
11 can be executed to adjust the corresponding SOC section, provided that constant-current
20 charging for at least one SOC section for which the predicted charging time value has been
determined by any one of the first and second embodiments described above with
reference to FIGS. 6 to 10 is actually completed. In explaining FIG. 11, it will be
assumed that j is a natural number greater than or equal to m and less than or equal to M.
41
Referring to FIGS. 1 to 11, in step S1110, the control unit 130 determines the
actual temperature change amount in the jth SOC section (Z[j]). If the j
th SOC section
(Z[j]) is the SOC section (e.g., Z[m]) at the charging start point using the multi-stage
constant-current charging protocol, the difference between the battery temperature
5 detection value at the charging start point and the battery temperature detection value at the
end point of the SOC section (Z[m]) may be determined as the actual temperature change
amount in the SOC section (Z[m]). Or, if the jth SOC section (Z[j]) is a SOC section (e.g.,
Z[M]) different from the SOC section (e.g., Z[m]) at the charging start point, the difference
between two battery temperature detection values at the start point and the end point of the
10 SOC section (Z[M]) may be determined as the actual temperature change amount in the
SOC section (Z[M]).
In step S1120, the control unit 130 determines whether the actual temperature
change amount in the j
th SOC section (Z[j]) is greater than the predicted temperature
change amount in the j
th SOC section (Z[j]).
15 Alternatively, the control unit 130 may correct the predicted temperature change
amount in the j
th SOC section (Z[j]) based on the two outdoor air temperature detection
values at the start point and the end point of the j
th SOC section (Z[j]), and then compare
the corrected predicted temperature change amount with the actual temperature change
amount in the j
th SOC section (Z[j]). Specifically, when determining the predicted
temperature change amount in the j
th 20 SOC section (Z[j]), TATM in Equation 3 may represent
the outdoor air temperature at the start point of the j
th SOC section (Z[j]). Since the
outdoor air temperature may change in the j
th SOC section (Z[j]), the predicted temperature
change amount in the j
th SOC section (Z[j]) can be corrected by calculating the temperature
42
correction value using Equation 5 below and then adding the temperature correction value
to the predicted temperature change amount in the j
th SOC section (Z[j]).

5 In Equation 5, TATM_1 may be the outdoor air temperature detection value at the
start point of the j
th SOC section (Z[j]), and TATM_2 may be the outdoor air temperature
detection value at the end point of the j
th SOC section (Z[j]). The values of other
parameters are common to Equation 4. According to Equation 5, if TATM_2 > TATM_1,
ΔTcorrect is positive, and the predicted temperature change amount in the j
th SOC section
10 (Z[j]) increases through correction. Conversely, if TATM_2 < TATM_1, ΔTcorrect is negative,
and the predicted temperature change amount in the j
th SOC section (Z[j]) decreases
through correction.
If the value of step S1120 is “Yes,” the process proceeds to step S1130.
In step S1130, the control unit 130 adjusts the j
th SOC section (Z[j]) according to
15 the difference between the actual temperature change amount and the predicted
temperature change amount in the j
th SOC section (Z[j]).
As an example, the control unit 130 may decrease the end point of the j
th SOC
section (Z[j]) by an adjustment value that has a predetermined positive correlation with
respect to the difference. Accordingly, the size of the j
th SOC section (Z[j]) is reduced by
the adjustment value. In addition, the fact that the end point of the j
th 20 SOC section (Z[j])
is advanced by the adjustment value means that the start point of the (j+1)
th SOC section
(Z[j+1]) is also advanced by the adjustment value. Therefore, the size of the (j+1)
th SOC
43
section (Z[j+1]) is increased by the adjustment value.
According to the third embodiment described above with reference to FIG. 11,
when the multi-stage constant-current charging protocol is carried out in the future, the
charging procedure for the SOC section with a history of temperature rise exceeding
5 expectations is terminated early, and the charging procedure for the SOC section following
the corresponding SOC section is started early. As can be seen from the reference current
profile 200 described above with reference to FIG. 2, if it is designed so that a relatively
small reference current value tends to be associated with a relatively high SOC section, the
reference current value that causes an excessive temperature rise is early switched to
10 another lower reference current value, so that the charging procedure using the multi-stage
constant-current charging protocol can be safely continued.
Additionally, the control unit 130 may also correct the reference charging map to
correspond to the correction (adjusting the size of a specific SOC section) of any one of the
plurality of reference charging maps (CM1 to CMN). For example, when a specific SOC
15 section of the reference charging map is adjusted, the specific SOC section of the reference
charging map may also be adjusted in the same way.
The embodiments of the present disclosure described above may not be
implemented only through an apparatus and a method, but may be implemented through a
program that realizes a function corresponding to the configuration of the embodiments of
20 the present disclosure or a recording medium on which the program is recorded. The
program or recording medium may be easily implemented by those skilled in the art from
the above description of the embodiments.
The present disclosure has been described in detail. However, it should be
44
understood that the detailed description and specific examples, while indicating preferred
embodiments of the disclosure, are given by way of illustration only, since various changes
and modifications within the scope of the disclosure will become apparent to those skilled
in the art from this detailed description.
5 Additionally, many substitutions, modifications and changes may be made to the
present disclosure described hereinabove by those skilled in the art without departing from
the technical aspects of the present disclosure, and the present disclosure is not limited to
the above-described embodiments and the accompanying drawings, and each embodiment
may be selectively combined in part or in whole to allow various modifications.

WHAT IS CLAIMED IS:
1. A battery management system, comprising:
a memory configured to store a plurality of reference charging maps associated
5 with a plurality of temperature sections, wherein each reference charging map including
first to Mth reference current values and first to Mth reference power curves associated with
first to Mth SOC sections, and M is a natural number greater than or equal to 2;
a sensing unit configured to detect voltage, current, and temperature of a battery;
and
10 a control unit configured to determine an estimated SOC value of the battery based
on the voltage detection value and the current detection value of the battery,
wherein the control unit is configured to:
obtain a mth reference power curve and a mth reference current value associated
with a mth SOC section to which the estimated SOC value belongs, from the reference
15 charging map associated with the temperature section to which the temperature detection
value of the battery belongs, wherein m is a natural number less than or equal to M, and
determine a mth predicted charging time value, which represents a time required
for an SOC of the battery to reach an end point of the mth SOC section, according to the
result of comparing a maximum output power of a charger that supplies charging power to
the battery and the mth 20 reference power curve, based on the difference between the end
point of the mth SOC section and the estimated SOC value, and at least one of the mth
reference current value, the maximum output power and the mth reference power curve.
46
2. The battery management system according to claim 1, wherein the control
unit is configured to determine an expected time required when performing a constantcurrent charging mode using the mth reference current value until the SOC of the battery
reaches the end point of the mth SOC section from the estimated SOC value as the mth
5 predicted charging time value, in response to that the maximum output power of the
charger is greater than or equal to a maximum power value of the mth reference power
curve.
3. The battery management system according to claim 1, wherein the control
10 unit is configured to determine an expected time required when performing a constantpower charging mode using the maximum output power until the SOC of the battery
reaches the end point of the mth SOC section from the estimated SOC value as the mth
predicted charging time value, in response to that the maximum output power of the
charger is less than or equal to a minimum power value of the mth reference power curve.
15
4. The battery management system according to claim 1, wherein the control
unit is configured to, in response to that the maximum output power of the charger is
between a minimum power value and a maximum power value of the mth reference power
curve:
20 determine an intersection SOC, which represents SOC at an intersection point of
the mth reference power curve and the maximum output power, and
determine the mth predicted charging time value based on the estimated SOC value,
the intersection SOC, the end point of the mth SOC section, the mth reference current value,
47
the maximum output power, and the mth reference power curve.
5. The battery management system according to claim 4, wherein the control
unit is configured to:
determine a mth 5 predicted constant-current charging time value, which represents
an expected time required when performing a constant-current charging mode using the
mth reference current value until the SOC of the battery reaches the intersection SOC from
the estimated SOC value,
determine a mth predicted constant-power charging time value, which represents an
10 expected time required when performing a constant-power charging mode using the
maximum output power until the SOC of the battery reaches the end point of the mth SOC
section from the intersection SOC, and
determine the mth predicted charging time value to be equal to the sum of the mth
predicted constant-current charging time value and the mth predicted constant-power
15 charging time value.
6. The battery management system according to claim 1, wherein the control
unit is configured to further determine a predicted temperature value at a start point of a
(m+1)th SOC section, when at least one SOC section subsequent to the mth SOC section
exists among the first to Mth 20 SOC sections.
7. The battery management system according to claim 6, wherein the control
unit is configured to:
48
determine a predicted temperature change amount until the SOC of the battery
reaches the start point of the (m+1)
th SOC section from the estimated SOC value, based on
the mth reference current value and the mth predicted charging time value, and
determine the predicted temperature value at the start point of the (m+1)
th SOC
5 section by adding the predicted temperature change amount from the estimated SOC value
to the end point of the mth SOC section to the temperature detection value.
8. The battery management system according to claim 6, wherein the control
unit is configured to, for k being a natural number greater than or equal to (m+1) and less
10 than or equal to M, in response to completing the determination of the predicted
temperature value at a start point of a k
th SOC section:
obtain a kth reference power curve and a kth reference current value associated with
the kth SOC section from the reference charging map associated with the temperature
section to which the predicted temperature value at the start point of the kth SOC section
15 belongs, and
determine a kth predicted charging time value, which represents a time required for
an SOC of the battery to reach the end point from the start point of the kth SOC section,
according to the result of comparing the maximum output power of the charger and the kth
reference power curve, based on a size of the kth SOC section, and at least one of the kth
reference current value, the maximum output power, and the kth 20 reference power curve.
9. The battery management system according to claim 8, wherein the control
unit is configured to, in response to completing the determination of the predicted charging
49
time value in the Mth SOC section, determine a total remaining time until the SOC of the
battery reaches the end point of the Mth SOC section from the estimated SOC value by
adding the mth to Mth predicted charging time values determined for the mth to Mth SOC
sections.
5
10. A battery pack, comprising the battery management system according to
any one of claims 1 to 9.
11. An electric vehicle, comprising the battery pack according to claim 10.
10
12. A battery charging time prediction method, comprising
determining an estimated SOC value of a battery based on a voltage detection
value and a current detection value of the battery;
obtaining a mth reference power curve and a mth reference current value associated
with a mth 15 SOC section to which the estimated SOC value belongs, from a reference
charging map associated with a temperature section to which a temperature detection value
of the battery belongs, among a plurality of reference charging maps associated with a
plurality of temperature sections, wherein each reference charging map including first to
Mth reference current values and first to Mth reference power curves associated with first to
Mth 20 SOC sections, M is a natural number greater than or equal to 2, and m is a natural
number less than or equal to M; and
determining a mth predicted charging time value, which represents a time required
for an SOC of the battery to reach an end point of the mth SOC section, according to the
50
result of comparing a maximum output power of a charger that supplies charging power to
the battery and the mth reference power curve, based on the difference between the end
point of the mth SOC section and the estimated SOC value, and at least one of the mth
reference current value, the maximum output power and the mth reference power curve.
5
13. The battery charging time prediction method according to claim 12,
wherein the step of determining the mth predicted charging time value is determining an
expected time required when performing a constant-current charging mode using the mth
reference current value until the SOC of the battery reaches the end point of the mth SOC
section from the estimated SOC value as the mth 10 predicted charging time value, in response
to that the maximum output power of the charger is greater than or equal to a maximum
power value of the mth reference power curve.
14. The battery charging time prediction method according to claim 12,
wherein the step of determining the mth 15 predicted charging time value is determining an
expected time required when performing a constant-power charging mode using the
maximum output power until the SOC of the battery reaches the end point of the mth SOC
section from the estimated SOC value as the mth predicted charging time value, in response
to that the maximum output power of the charger is less than or equal to a minimum power
value of the mth 20 reference power curve.
15. The battery charging time prediction method according to claim 12,
wherein the step of determining the mth predicted charging time value includes, in response
51
to that the maximum output power of the charger is between a minimum power value and a
maximum power value of the mth reference power curve:
determining an intersection SOC associated with the same power value as the
maximum output power from the mth reference power curve;
determining a mth 5 predicted constant-current charging time value, which represents
an expected time required when performing a constant-current charging mode using the
mth reference current value until the SOC of the battery reaches the intersection SOC from
the estimated SOC value;
determining a mth predicted constant-power charging time value, which represents
10 an expected time required when performing a constant-power charging mode using the
maximum output power until the SOC of the battery reaches the end point of the mth SOC
section from the intersection SOC; and
determining the mth predicted charging time value to be equal to the sum of the mth
predicted constant-current charging time value and the mth predicted constant-power
15 charging time value.