FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
“BATTERY MANAGEMENT SYSTEM AND BATTERY
PACK”
LG ENERGY SOLUTION, LTD., of Tower 1, 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.
2
[DESCRIPTION]
[TITLE OF INVENTION]
BATTERY MANAGEMENT SYSTEM AND BATTERY PACK
[TECHNICAL FIELD]
5 Cross-reference to Related Applications
This application claims the benefit of Korean Patent
Application No. 10-2019-0097000 filed on August 08, 2019, in
the Korean Intellectual Property Office, the disclosure of
which is incorporated herein in its entirety by reference.
10 Technical Field
The present invention relates to a battery management
system and a battery pack.
[BACKGROUND ART]
In order to accurately estimate the remaining capacity,
15 life, and available power of a battery, in addition to
accurately measuring the voltage and current of the battery
cell unit, module unit, and pack unit, the measurement timing
point of the corresponding voltage and current must be
consistent.
20 However, for example, in the wireless communicationbased system structure in which a plurality of battery
management systems such as a lower-level battery management
system (hereinafter referred to as 'BMS') (for example, a
module BMS) and an upper-level battery management system (for
25 example, a pack BMS) are provided, as an example, since the
synchronization signal for voltage or current measurement
cannot be collectively received from the higher-level
controller (for example, a master BMS) outside the battery
pack, when each BMS individually measures the cell voltage,
30 pack voltage, and the like, the measurement timing point is
3
not consistent, so that there was a problem in that it was
not possible to accurately estimate the remaining capacity,
life, and usable output of the battery.
[DISCLOSURE OF THE INVENTION]
5 [TECHNICAL PROBLEM]
The present invention has been made to solve the above
problems, and provides a battery management system and a
battery pack capable of matching measurement timing point of
voltage and current within a battery without a control signal
10 from a host controller outside the battery.
[TECHNICAL SOLUTION]
A battery management system according to an embodiment
of the present invention includes: a pack voltage sampling
unit configured to periodically sample a pack voltage of a
15 battery pack; a pack current sampling unit configured to
sample a pack current of the battery pack; and a control unit
configured to, after starting to sample the pack voltage of
the battery pack, when the pack voltage sampling of the
battery pack is completed, record a time from a sampling
20 start time of the pack voltage to a sampling completion time
of the pack voltage as a first time, and transmit a voltage
sampling synchronization signal for measuring a cell voltage
of a battery cell to a plurality of lower-level battery
management systems. At this time, the control unit performs
25 sampling synchronization on the sampled measurement signal
between each lower-level battery management system based on a
second time, which is a sampling time at which a cell voltage
measurement received from each lower-level battery management
system is performed, and the first time.
30 The battery management system according to an
embodiment of the present invention may further include a
4
communication unit including a transmission unit for
wirelessly broadcasting the voltage sampling synchronization
signal to the plurality of lower-level battery management
systems and a reception unit for wirelessly receiving the
5 second time from each lower-level battery management system
and cell voltage sampling information for the second time.
For example, after the transmission unit transmits a
measurement synchronization signal to the plurality of lowerlevel battery management systems after the pack voltage
10 sampling is completed, the pack current sampling unit may
perform the pack current sampling.
The second time may be a difference between a time when
the lower-level battery management system starts measuring a
cell voltage in the lower-level battery management system
15 after receiving the measurement synchronization signal and a
time when the cell voltage measurement ends.
In addition, the control unit may delay a sampling
start time point of the pack voltage by 1/2 of the second
time, and locate a generation time point of the voltage
20 sampling synchronization signal to be in the middle of the
second time, so that the control unit performs the sampling
synchronization by synchronizing the cell voltage sampling
information received from the plurality of lower-level
battery management systems and the measurement time of the
25 sampling information of the pack voltage sampling unit.
For example, the control unit may transmit the cell
voltage sampling information for performing the sampling
synchronization to an upper-level controller.
In addition, a battery management system according to
30 another embodiment of the present invention includes: a
5
reception unit configured to receive a voltage sampling
synchronization signal for measuring a cell voltage of a
battery cell from a higher-level battery management system; a
cell voltage sampling unit configured to sample a cell
5 voltage of a battery cell when receiving the voltage sampling
synchronization signal; a control unit configured to
calculate a second time, which is a time from a time point at
which the cell voltage sampling is started to a time point at
which the cell voltage sampling is completed; and a
10 transmission unit configured to transmit the calculated
second time and cell voltage sampling information during the
second time to the higher-level battery management system.
Moreover, a battery pack according to another
embodiment of the present invention includes a plurality of
15 lower-level battery management systems and at least one
higher-level battery management system, wherein the higherlevel battery management system includes: a pack voltage
sampling unit configured to periodically sample a pack
voltage of a battery pack; a pack current sampling unit
20 configured to sample a pack current of the battery pack; and
a first control unit configured to, after starting to sample
the pack voltage of the battery pack, when the pack voltage
sampling of the battery pack is completed, record a time from
a sampling start time of the pack voltage to a sampling
25 completion time of the pack voltage as a first time, and
transmit a voltage sampling synchronization signal for
measuring a cell voltage of a battery cell to the plurality
of lower-level battery management systems, wherein each
lower-level battery management system includes: a cell
30 voltage sampling unit configured to sample a cell voltage of
6
a battery cell when receiving a voltage sampling
synchronization signal for measuring a cell voltage of a
battery cell from the higher-level battery management system;
and a second control unit configured to calculate a second
5 time, which is a time from a time point at which the cell
voltage sampling is started to a time point at which the cell
voltage sampling is completed, and transmits the calculated
second time and cell voltage sampling information during the
second time to the higher-level battery management system,
10 wherein the first control unit performs sampling
synchronization on the sampled measurement signal between
each lower-level battery management system based on the
second time received from each lower-level battery management
system and the first time.
15 For example, wireless communication is performed
between the higher-level battery management system and each
lower-level battery management system.
The control unit may delay a sampling start time point
of the pack voltage by 1/2 of the second time, and locate a
20 generation time point of the voltage sampling synchronization
signal to be in the middle of the second time, so that the
control unit performs the sampling synchronization by
synchronizing the cell voltage sampling information received
from the plurality of lower-level battery management systems
25 and the measurement time of the sampling information of the
pack voltage sampling unit.
The pack current sampling unit may perform the pack
current sampling after the pack voltage sampling is completed
and a measurement synchronization signal is transmitted to
30 the plurality of lower-level battery management systems.
7
In addition, the first control unit may transmit the
cell voltage sampling information for performing the sampling
synchronization to an upper-level controller.
[EFFECTS OF THE INVENTION]
5 According to the present invention, it is possible to
match the measurement timing point such as voltage and
current in the battery without a control signal from a host
controller outside the battery, so that the remaining
capacity, life, and available output of the battery can be
10 more accurately estimated.
Other effects according to the present invention will
be described further according to the following examples.
[BRIEF DESCRIPTION OF THE DRAWINGS]
FIG. 1 is a block diagram schematically showing the
15 configuration of a general battery pack.
FIG. 2 is a block diagram schematically showing the
configuration of a battery pack based on wireless
communication according to an embodiment of the present
invention.
20 FIG. 3 is a block diagram schematically showing the
configuration of the pack BMS of FIG. 2.
FIG. 4 is a block diagram schematically showing the
configuration of the module BMS of FIG. 2.
FIG. 5 is a timing chart for explaining a process of
25 performing synchronization on a measurement signal, and FIG.
5A is a timing chart before synchronization, and FIG. 5B is a
timing chart after synchronization.
FIG. 6 is a flowchart illustrating a measurement
synchronization method of a battery management system.
30 FIG. 7 is a block diagram showing a hardware
8
configuration of a battery management system (BMS) according
to an embodiment of the present invention.
[MODE FOR CARRYING OUT THE INVENTION]
Hereinafter, various embodiments of the present
5 invention will be described with reference to the
accompanying drawings. However, this is not intended to limit
the present invention to a specific embodiment, it should be
understood to include various modifications, equivalents,
and/or alternatives of the embodiments of the present
10 invention. In relation to the description of the drawings,
like reference numerals may be used for like elements.
Terms used in this document are only used to describe a
specific embodiment, and may not be intended to limit the
scope of other embodiments. The terms of a singular form may
15 include plural forms unless otherwise specified. All terms
used herein, including technical or scientific terms, may
have the same meaning as commonly understood by a person of
ordinary skill in the art. Terms defined in a commonly used
dictionary may be interpreted as having the same or similar
20 meaning as the meaning in the context of the related
technology, and are not interpreted as ideal or excessively
formal meanings unless explicitly defined in this document.
In some cases, even terms defined in this document cannot be
interpreted to exclude embodiments of the present invention.
25 In addition, in describing the constituent elements of
the embodiment of the present invention, terms such as first,
second, A, B, (a), and (b) may be used. These terms are only
for distinguishing the component from other components, and
the nature, order, or sequence of the component is not
30 limited by the terms. If a component is described as being
9
"connected", "coupled" or "jointed" to another component, the
component may be directly connected or accessed to the other
component, but it will be understood that another component
may be "connected", "coupled" or "jointed" between each
5 component.
Referring to FIG. 1, a basic configuration of a battery
pack will be described. FIG. 1 is a block diagram
schematically showing the configuration of a general battery
pack.
10 As shown in FIG. 1, the battery pack B includes at
least one battery module 1 consisting of one or more battery
cells and capable of charging and discharging, a switching
unit 2 connected in series to the + terminal side or theterminal side of the battery module 1 to control the
15 charge/discharge current flow of the battery module 1, and a
battery management system 3 for controlling and managing the
voltage, current, temperature, and the like of the battery
pack B to prevent overcharging and overdischarging.
Here, the switching unit 2 is a mechanical switching
20 element or semiconductor switching element for controlling
the current flow for charging or discharging of the battery
module 1, and for example, at least one mechanical relay or
MOSFET may be used.
In addition, in order to monitor the voltage, current,
25 temperature, and the like of the battery pack B, the BMS 3 is
connected to the battery module 1 and can receive data on
voltage, current, temperature, and the like. Further, for
example, when the switching unit 2 is a semiconductor
switching element, it is possible to measure or calculate the
30 voltage and current of the gate, source and drain of a
10
semiconductor switching device, and in addition, current,
voltage, temperature, and the like of the battery module 1
can also be measured using various sensors 4 provided
adjacent to the semiconductor switching element. The data
5 such as current, voltage, and temperature obtained as
described above can be used to estimate the remaining
capacity, life, and available output of the battery. The BMS
3 is an interface for receiving values obtained by measuring
the above-described various parameters, and may include a
10 plurality of terminals and a circuit connected to these
terminals to process input values.
In addition, the BMS 3 may control ON/OFF of the
switching unit 2 and may be connected to the battery module 1
to monitor the state of the battery module 1.
15 The battery pack B of FIG. 1 is provided as a unit of
one battery module depending on the application, and the like,
and a plurality of battery packs B may be connected in series
or in parallel to form one battery pack (or battery rack). In
this case, although not shown in the drawing, for example,
20 the battery pack includes a plurality of lower-level battery
management systems (e.g., module BMS) provided in each
battery module unit, and at least one upper-level battery
management system (e.g., pack BMS) for managing the plurality
of lower-end battery management systems.
25 Here, the lower-level battery management system
provided in each battery module unit may control charging and
discharging of the corresponding battery module by measuring
a cell voltage or a module voltage in the corresponding
battery module, and in addition, may transmit the measured
30 cell voltage or module voltage to the higher-level battery
11
management system, and may also receive control commands
necessary for charging and discharging from the higher-level
battery management system.
Similarly, a higher-level battery management system for
5 managing a plurality of lower-level battery management
systems may measure the total pack voltage or pack current,
and the like, in which a plurality of battery modules are
connected in series and parallel, and in addition, may
receives cell voltage or module voltage from each lower-level
10 battery management system, and may control charging and
discharging of the battery pack, and may transmit a control
command required for charging and discharging to each lowerlevel battery management system.
In this case, data can be transmitted and received
15 between the battery management systems through wireless
communication. In this case, it is required to synchronize
the measurement signal from the lower-level battery
management system and the measurement signal from the higherlevel battery management system.
20 Next, a method of synchronizing measurement signals
between battery management systems according to an embodiment
of the present invention will be described with reference to
FIGS. 2 to 4. FIG. 2 is a block diagram schematically showing
the configuration of a wireless communication-based battery
25 pack according to an embodiment of the present invention, FIG.
3 is a block diagram schematically showing the configuration
of the pack BMS of FIG. 2, and FIG. 4 is a block diagram
schematically showing the configuration of the module BMS of
FIG. 2.
30 As shown in FIG. 2, the battery pack 100 according to
12
an embodiment of the present invention includes at least one
pack BMS 10 and a plurality of module BMSs 20.
First, the pack BMS 10, as a higher-level battery
management system, may include a pack voltage sampling unit
5 11, a pack current sampling unit 13, and a first control unit
15 as shown in FIG. 3.
The pack voltage sampling unit 11 periodically samples
the pack voltage of the battery pack. For example, a pack
voltage signal measured from a terminal for measuring the
10 pack voltage is periodically sampled.
The pack current sampling unit 13 samples the pack
current of the battery pack. For example, a pack current
signal measured from a sensor for measuring the pack current
is sampled. For example, the pack current sampling unit 13
15 may perform pack current sampling after the pack voltage
sampling is completed and the measurement synchronization
signal is transmitted to the plurality of modules BMSs 20.
After starting to sample the pack voltage of the
battery pack, when sampling the pack voltage of the battery
20 pack is completed, the first control unit 15 records the time
from the sampling start time of the pack voltage to the
sampling completion time of the pack voltage as a first time,
and controls to transmit a voltage sampling synchronization
signal for measuring the cell voltage of the battery cell to
25 the plurality of modules BMSs 20.
In addition, the pack BMS 10 may further include a
first communication unit 17 to communicate with the plurality
of module BMSs 20.
The first communication unit 17 may include, for
30 example, a transmission unit 17A for wirelessly broadcasting
13
a voltage sampling synchronization signal or the like to the
plurality of modules BMSs 20, and a reception unit 17B for
wirelessly receiving a data signal or the like from each
module BMS 20. For example, the reception unit 17B may
5 receive a second time, which is a sampling time at which cell
voltage measurement is performed and measurement signal data,
which is the cell voltage sampling information during the
second time, from each module BMS 20. For example, the second
time may be a difference between a time when the module BMS
10 20 starts measuring the cell voltage in the module BMS 20
after receiving the measurement synchronization signal and a
time when the cell voltage measurement is completed.
In addition, the pack BMS 10 may further include a
memory (not shown) for recording the first time, the second
15 time, and the measurement signal data.
Meanwhile, each module BMS 20 is a lower-level battery
management system, and may include a cell voltage sampling
unit 21 and a second control unit 25 as shown in FIG. 4.
The cell voltage sampling unit 21 samples the cell
20 voltage of the battery cell when receiving a voltage sampling
synchronization signal for measuring the cell voltage of the
battery cell from the pack BMS 10. In addition, when
receiving a voltage sampling synchronization signal for
measuring the cell voltage of the battery cell from the pack
25 BMS 10, the cell voltage sampling unit 21 may further sample
a module voltage of a battery module in which the
corresponding battery cells are connected in series and/or in
parallel.
The second control unit 25 calculates a second time,
30 which is a time from when sampling is started to when
14
sampling is completed, for a measurement signal such as a
cell voltage, and controls to transmit the calculated second
time and measurement sampling information for the second time
to the pack BMS 10.
5 In addition, each module BMS 20 may further include a
second communication unit 27 to communicate with the pack BMS
10.
The second communication unit 27, for example, may
include a reception unit 27B for wirelessly receiving a
10 voltage sampling synchronization signal for measuring the
cell voltage of the battery cell from the pack BMS 10, and a
transmission unit 27A for wirelessly transmitting measurement
signal data for sampling information, such as a cell voltage
for the second time and the second time, to the pack BMS 10.
15 Accordingly, signals can be transmitted and received through
wireless communication between the pack BMS 10 and the module
BMS 20 or between different module BMSs 20.
Additionally, the module BMS 20 may further include a
memory (not shown) for recording the second time and
20 measurement signal data.
Here, the first control unit 15 of the pack BMS 10
synchronizes a measurement signal such as a pack voltage
measured by the pack BMS 10 and a measurement signal such as
a cell voltage measured by the module BMS 20. Specifically,
25 based on a second time that is a sampling time at which the
cell voltage measurement received from each module BMS 20 is
performed, and a first time related to the pack voltage
sampling, sampling synchronization is performed on the
measured signal sampled between each module BMS 20. For
30 example, as the sampling start time point of the pack voltage
15
is delayed by 1/2 of the second time, and the generation time
point of the voltage sampling synchronization signal is
located in the middle of the second time, the first control
unit 15 may synchronize the cell voltage sampling information
5 received from the plurality of modules BMSs 20 and the
measurement time of the sampling information of the pack
voltage sampling unit 11 to perform sampling synchronization.
A process of performing synchronization on a
measurement signal will be described in detail with reference
10 to FIG. 5. FIG. 5 is a timing chart for explaining a process
of performing synchronization on a measurement signal, and
FIG. 5A is a timing chart before synchronization, and FIG. 5B
is a timing chart after synchronization.
As shown in Fig. 5A, before synchronization is
15 performed, the pack voltage sampling unit 11 of the pack BMS
10 first periodically samples the pack voltage VPACK during
Δp (i.e., the pack voltage measurement time, the first time).
Immediately after the sampling of the pack voltage is
completed, the first control unit 15 generates a sampling
20 synchronization signal MSR Trig. and transmits the sampling
synchronization signal MSR Trig. to the module BMS 20, and in
addition, the pack current sampling unit 13 samples the pack
current IPACK during Δc (i.e., the pack current measurement
time). On the other hand, based on the received sampling
25 synchronization signal MSR Trig., the cell voltage sampling
unit 21 of the module BMS 20 sequentially samples the cell
voltage VCELL for each of cells 1 to 96 during △s. However,
in FIG. 5A, it is illustrated that the cells are sequentially
sampled for Δ s in units of 6, but is not limited thereto.
30 Additionally, based on the received sampling synchronization
16
signal MSR Trig., the cell voltage sampling unit 21 may
further sample the module voltage VMODULE for a predetermined
time (e.g., Δs/2). Here, the pack voltage VPACK and the pack
current IPACK are data measured from the pack BMS 10, and the
5 cell voltage VCELL and the module voltage VMODULE are data
measured from the module BMS 20. In addition, the pack BMS 10
may measure and record Δp and Δc based on, for example, an
internal clock signal by a clock generator (not shown)
provided therein, and likewise, the module BMS 20 may measure
10 and record Δs based on, for example, an internal clock signal
generated by a clock generator (not shown) provided therein.
Here, Δh denotes a cycle time for transmitting the cell
voltage measurement signal from the module BMS 20 to the pack
BMS 10.
15 Meanwhile, the first control unit 15 may perform
sampling synchronization on the sampled measurement signals
of the pack voltage VPACK, the pack current IPACK, the cell
voltage VCELL, and the module voltage VMODULE. For example,
as shown in FIG. 5B, as the sampling start time point of the
20 pack voltage is delayed by 1/2 of the second time (i.e., by
Δs/2) and the generation time point of the voltage sampling
synchronization signal MSR Trig. is located in the middle of
the second time, sampling synchronization can be performed by
synchronizing the measurement time of the sampling
25 information VCELL and VMODULE received from each module BMS
20 and the sampling information VPACK and IPACK measured by
the pack BMS 10 itself.
In such a way, according to the present invention, it
is possible to match the measurement timing point such as
30 voltage and current in the battery without a control signal
17
from a host controller outside the battery, so that the
remaining capacity, life, and available output of the battery
can be more accurately estimated.
Additionally, the first control unit 10 of the pack BMS
5 10 may transmit sampling result information obtained by
performing sampling synchronization to the upper-level
controller 200. For example, cell voltage sampling
information may be transmitted to the upper-level controller
200. In addition, the first control unit 10 of the pack BMS
10 10 may transmit information on the state and control of the
battery to the upper-level controller 200, or control the
operation of the battery pack 100 based on a control signal
applied from the upper-level controller 200. The first
control unit 10 of the pack BMS 10 may exchange various
15 signals and data with the upper-level controller 200 by wire
and/or wirelessly. Here, the battery pack 100 may be, for
example, a battery pack of an energy storage system (ESS),
and the upper-level controller 200 may be, for example, a
master BMS that integrates and manages the plurality of
20 battery packs 100. However, the present invention is not
limited thereto, and the battery pack 100 may be an
automobile battery pack, and the upper-level controller 200
may be a microcontroller (MCU) of an automobile system.
Meanwhile, the present invention may be implemented as
25 a higher-level battery management system such as the pack BMS
10, which is applied in the battery pack 100, and may be
implemented as a lower-level battery management system such
as the module BMS 20. However, since the higher-level battery
management system and the lower-level battery management
30 system are the same as described above, detailed descriptions
18
will be omitted.
Next, a measurement synchronization method of the pack
BMS 10 will be described with reference to FIG. 6. FIG. 6 is
a flowchart illustrating a measurement synchronization method
5 of a battery management system.
First, when the pack BMS 10 starts measuring, the pack
voltage sampling unit 11 starts sampling the pack voltage
(S10). Next, it is determined whether the sampling of the
pack voltage has been completed under a predetermined
10 condition (S11). For example, the predetermined condition may
be a predetermined time or a predetermined number of sampling
times. If it is determined that the sampling of the pack
voltage has not been completed (N), the internal clock CLK1++
is added to △p (i.e., the pack voltage measurement time, the
15 first time) (S13), and the process returns to operation S11.
If, in operation S11, when it is determined that the sampling
of the pack voltage is complete (Y), the first control unit
15 extracts Δp, generates a measurement synchronization
signal MSR Trig. with this, and transmits the signal to the
20 module BMS 20 (S20). First, when the pack BMS 13 starts
measuring, the pack voltage sampling unit 11 starts sampling
the pack voltage (S10). Next, it is determined whether the
sampling of the pack current has been completed under a
predetermined condition (S31). For example, the predetermined
25 condition may be a predetermined time or a predetermined
number of sampling times. If it is determined that sampling
of the pack current has not been completed (N), the internal
clock CLK1++ is added to △c (i.e., the pack current
measurement time) (S33), and the process returns to operation
30 S31. If, in operation S31, when it is determined that
19
sampling of the pack current is completed (Y), the first
control unit 15 extracts △c (S35).
On the other hand, after step S20, the cell voltage
sampling unit 21 of the module BMS 20 starts sampling the
5 cell voltage and/or the module voltage when the measurement
synchronization signal MSR Trig. is received (S40). For
example, the module voltage sampling time may be 1/2 of the
cell voltage sampling time. Next, it is determined whether
the cell voltage sampling has been completed under a
10 predetermined condition (S41). For example, the predetermined
condition may be a predetermined time or a predetermined
number of sampling times. If it is determined that the cell
voltage sampling has not been completed (N), an internal
clock CLK2++ is added to Δs (i.e., the cell voltage
15 measurement time in the module BMS 20, the second time) (S43),
and the process returns to operation S41. If, in operation
S41, when it is determined that the sampling of the cell
voltage is completed (Y), △s is extracted (S45).
Subsequently, the module BMS 20 transmits the Δ s/2 value to
20 the pack BMS 10 (S50). Subsequently, the first control unit
15 of the pack BMS 10 delays the measurement time of the pack
voltage and the pack current by Δs/2 based on the received
Δs/2 value, and performs sampling synchronization between the
sampling signal measured in the pack BMS 10 and the sampling
25 signal measured in the module BMS 20, and returns to
operation S10 again, so that the measurement synchronization
process may be periodically repeated. Here, the module BMS 20
transmits the Δs/2 value to the pack BMS 10, but the module
BMS 20 may transmit the Δs value, and the pack BMS 10 may
30 delay the Δs/2 value.
20
Meanwhile, the lower-level or higher-level battery
management system of the battery pack 100 of the present
invention may be expressed in hardware as shown in FIG. 7.
FIG. 7 is a block diagram showing the hardware configuration
5 of the battery management system 300 according to an
embodiment of the present invention.
As shown in FIG. 7, the battery management system 300
may include a microcontroller (MCU) 310 that controls various
processes and configurations, a memory 320 in which an
10 operating system program and various programs (e.g., a
sampling synchronization program, a battery pack abnormality
diagnosis program, or a battery pack temperature estimation
program) are recorded, an input/output interface 330 that
provides an input interface and an output interface between a
15 battery module and/or a switching unit (e.g., a semiconductor
switching device), and a communication interface 340 capable
of communicating with an external (for example, upper-level
controller) through a wired or wireless communication network.
In this way, the computer program according to the present
20 invention may be recorded in the memory 320 and processed by
the microcontroller 310, and for example, may be implemented
as a module that performs each functional block shown in FIGS.
2 to 4.
In such a way, according to the present invention, it
25 is possible to match the measurement timing point such as
voltage and current in the battery without a control signal
from a host controller outside the battery, so that the
remaining capacity, life, and available output of the battery
can be more accurately estimated.
30 In the above, although the present invention has been
21
described by the limited embodiments and drawings, the
present invention is not limited thereto, and it is apparent
that various implementations are possible within the
equivalent range of the technical idea of the present
5 invention and the claims to be described below by those of
ordinary skill in the technical field to which the present
invention belongs.
22
[WE CLAIMS]
1. A battery management system comprising:
a pack voltage sampling unit configured to periodically
5 sample a pack voltage of a battery pack;
a pack current sampling unit configured to sample a
pack current of the battery pack; and
a control unit configured to, after starting to sample
the pack voltage of the battery pack, when the pack voltage
10 sampling of the battery pack is completed, record a time from
a sampling start time of the pack voltage to a sampling
completion time of the pack voltage as a first time, and
transmit a voltage sampling synchronization signal for
measuring a cell voltage of a battery cell to a plurality of
15 lower-level battery management systems,
wherein the control unit performs sampling
synchronization on sampled measurement signals between each
lower-level battery management system based on a second time,
which is a sampling time at which a cell voltage measurement
20 received from each lower-level battery management system is
performed, and the first time.
2. The battery management system of claim 1, further
comprising a communication unit including a transmission unit
25 for wirelessly broadcasting the voltage sampling
synchronization signal to the plurality of lower-level
battery management systems and a reception unit for
wirelessly receiving the second time from each lower-level
battery management system and cell voltage sampling
30 information for the second time.
23
3. The battery management system of claim 2, wherein
after the transmission unit transmits the measurement
synchronization signal to the plurality of lower-level
5 battery management systems and after the pack voltage
sampling is completed, the pack current sampling unit
performs the pack current sampling.
4. The battery management system of claim 1, wherein
10 the second time is a difference between a time when the
lower-level battery management system starts measuring a cell
voltage in the lower-level battery management system after
receiving the measurement synchronization signal and a time
when the cell voltage measurement ends.
15
5. The battery management system of claim 4, wherein
the control unit delays a sampling start time point of the
pack voltage by 1/2 of the second time, and locates a
generation time point of the voltage sampling synchronization
20 signal to be in the middle of the second time, so that the
control unit performs the sampling synchronization by
synchronizing the cell voltage sampling information received
from the plurality of lower-level battery management systems
and the measurement time of the sampling information of the
25 pack voltage sampling unit.
6. The battery management system of claim 5, wherein
the control unit transmits the cell voltage sampling
information for performing the sampling synchronization to an
30 upper-level controller.
24
7. A battery management system comprising:
a reception unit configured to receive a voltage
sampling synchronization signal for measuring a cell voltage
5 of a battery cell from a higher-level battery management
system;
a cell voltage sampling unit configured to sample a
cell voltage of the battery cell when receiving the voltage
sampling synchronization signal;
10 a control unit configured to calculate a second time,
which is a time from a time point at which the cell voltage
sampling is started to a time point at which the cell voltage
sampling is completed; and
a transmission unit configured to transmit the
15 calculated second time and cell voltage sampling information
during the second time to the higher-level battery management
system.
8. A battery pack comprising a plurality of lower20 level battery management systems and at least one higherlevel battery management system,
wherein the higher-level battery management system
comprises:
a pack voltage sampling unit configured to periodically
25 sample a pack voltage of the battery pack;
a pack current sampling unit configured to sample a
pack current of the battery pack; and
a first control unit configured to, after starting to
sample the pack voltage of the battery pack, when the pack
30 voltage sampling of the battery pack is completed, record a
25
time from a sampling start time of the pack voltage to a
sampling completion time of the pack voltage as a first time,
and transmit a voltage sampling synchronization signal for
measuring a cell voltage of a battery cell to the plurality
5 of lower-level battery management systems,
wherein each lower-level battery management system
comprises:
a cell voltage sampling unit configured to sample a
cell voltage of a battery cell when receiving a voltage
10 sampling synchronization signal for measuring a cell voltage
of the battery cell from the higher-level battery management
system; and
a second control unit configured to calculate a second
time, which is a time from a time point at which the cell
15 voltage sampling is started to a time point at which the cell
voltage sampling is completed, and transmits the calculated
second time and cell voltage sampling information during the
second time to the higher-level battery management system,
wherein the first control unit performs sampling
20 synchronization on the sampled measurement signal between
each lower-level battery management system based on the
second time received from each lower-level battery management
system and the first time.
25 9. The battery pack of claim 8, wherein wireless
communication is performed between the higher-level battery
management system and each lower-level battery management
system.
30 10. The battery pack of claim 8, wherein the control
26
unit delays a sampling start time point of the pack voltage
by 1/2 of the second time, and locates a generation time
point of the voltage sampling synchronization signal to be in
the middle of the second time, so that the control unit
5 performs the sampling synchronization by synchronizing the
cell voltage sampling information received from the plurality
of lower-level battery management systems and the measurement
time of the sampling information of the pack voltage sampling
unit.
10
11. The battery pack of claim 8, wherein the pack
current sampling unit performs the pack current sampling
after the pack voltage sampling is completed and a
measurement synchronization signal is transmitted to the
15 plurality of lower-level battery management systems.
12. The battery pack of claim 8, wherein the first
control unit transmits the cell voltage sampling information
for performing the sampling synchronization to an upper-level
20 controller.