FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
“BATTERY MANAGEMENT SYSTEM AND CONTROL
METHOD THEREOF”
LG ENERGY SOLUTION, LTD., of Tower 1, 108, Yeoui-daero, 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
BATTERY MANAGEMENT SYSTEM AND CONTROLLING METHOD
THEREOF
TECHNICAL FIELD
Cross-reference to Related Applications
[0001] This application claims the benefit of Korean Patent Application No. 10-2019-
0148979, filed on November 19, 2019, in the Korean Intellectual Property Office, the
disclosure of which is incorporated herein in its entirety by reference.
Technical Field
[0002] Embodiments of the present invention relate to a battery management system
and a controlling method thereof.
BACKGROUND ART
[0003] With the generalization of portable electronic devices such as smart phones and
tablets, research and development on chargeable/dischargeable secondary batteries are
being actively conducted with the spread of electric vehicles and energy storage devices.
A lithium ion battery in particular among secondary batteries has an advantage in that the
energy density thereof is much higher than that of typical Ni/Cd batteries, Ni/MH batteries,
and the like. Also, a lithium ion battery can be manufactured small and lightweight, and
thus, is used as a power source of mobile devices. In addition, a lithium ion battery has
attracted attention as a next generation energy storage medium since the range of use
thereof has been expanded to being a power source of electric vehicles.
[0004] A secondary battery such as a lithium-ion battery is used in the form of a
battery module including a cell module in which a plurality of battery cells are connected
in series and/or in parallel and a battery management system (BMS) for controlling the
charge/discharge of the cell module. In addition, a secondary battery may be used in the
form of a battery pack in which a plurality of battery modules are coupled according to an
output specification required by an object on which the battery is mounted. In addition, a
battery management system for managing the entire battery pack may be additionally
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provided as a master battery management system.
[0005] A battery system composed of a plurality of battery modules may include a
master battery management system and a plurality of slave battery management systems.
The master battery management system is capable of controlling and managing the
operation of the plurality of slave battery management systems and communicating with a
higher-level system. The master battery management system and the plurality of slave
battery management systems transmit and receive signals wirelessly. Therefore, there is a
need for a lot of research to perform wireless communication efficiently and stably among
battery management systems.
DISCLOSURE OF THE INVENTION
TECHNICAL PROBLEM
[0006] An aspect of the present invention provides a method in which each battery
management system may efficiently use limited resources in a battery system in which a
plurality of battery management systems communicate wirelessly.
TECHNICAL SOLUTION
[0007] According to an aspect of preset invention, a battery management system in a
system in which each of a plurality of battery management systems performs a task
individually set and transmits results of the performed tasks to a master battery
management system via wireless communication includes a task information storage unit
including a list of tasks performed by each of the plurality of battery management systems,
the performance time, performance cycle, and work priority of each task included in the
list of tasks, and the communication priority among the plurality of battery management
systems, a schedule determination unit for determining a work schedule on the basis of
data stored in the task information storage unit, and a priority changing unit for adjusting
the work priority of a task on the basis of the work schedule determined by the schedule
determination unit, wherein the schedule determination unit adjust the work schedule
according to the adjusted work priority.
[0008] According to another aspect of preset invention, a control method of a battery
management system includes storing a list of tasks performed by each of a plurality of
battery management systems, the performance time, performance cycle, and work priority
of each task included in the list of tasks, and the communication priority among the
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plurality of battery management systems, determining a work schedule on the basis of the
stored data, adjusting the work priority of a task on the basis of the determined work
schedule, and adjusting the work schedule according to the adjusted work priority.
ADVANTAGEOUS EFFECTS
[0009] According to the above battery management system and control method thereof,
it is possible to use limited resources efficiently. In addition, without changing hardware
such as mycom, it is possible to perform tasks which have not been performed before.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The following drawings attached to the specification illustrate preferred
examples of the present invention by example, and serve to enable technical concepts of
the present invention to be further understood together with detailed description of the
invention given below, and therefore the present invention should not be interpreted only
with matters in such drawings.
[0011] FIG. 1 is a configuration diagram schematically showing a battery system
according to an embodiment of the present invention;
[0012] FIG. 2 is a configuration diagram of a battery pack including a battery
management system according to an embodiment of the present invention;
[0013] FIG. 3 is a functional block diagram showing the configuration of a battery
management system according to an embodiment of the present invention;
[0014] FIG. 4 is a functional block diagram showing a work scheduler in a battery
management system according to an embodiment of the present invention;
[0015] FIG. 5 is a flow chart showing the operation of a battery management system
according to an embodiment of the present invention;
[0016] FIG. 6 is a diagram showing a task timetable according to an embodiment of
the present invention;
[0017] FIG. 7 is a diagram showing a communication priority table according to an
embodiment of the present invention;
[0018] FIG. 8 is a flow chart showing a work scheduling operation of a battery
management system according to an embodiment of the present invention;
[0019] FIG. 9 is a timing diagram showing the order of operation of a task according
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to FIG. 6 and FIG. 7;
[0020] FIG. 10 is a timing diagram showing the order of operation of a task whose
work priority has been changed by a battery management system according to an
embodiment of the present invention;
[0021] FIG. 11 is a diagram showing a task timetable according to another
embodiment of the present invention;
[0022] FIG. 12 is a diagram showing a communication priority table according to
another embodiment of the present invention;
[0023] FIG. 13 is a timing diagram showing the order of operation of a task according
to FIG. 11 and FIG. 12;
[0024] FIG. 14 is a flow chart showing a method for changing work priority according
to an embodiment of the present invention;
[0025] FIG. 15 is a flow chart showing an example of a method for changing work
priority according to an embodiment of the present invention;
[0026] FIG. 16 is a timing diagram showing the order of operation of a task whose
work priority has been changed by the method for changing work priority according to FIG.
15;
[0027] FIG. 17 is a flow chart showing another example of a method for changing
work priority according to an embodiment of the present invention;
[0028] FIG. 18 is a timing diagram showing the order of operation of a task whose
work priority has been changed by the method for changing work priority according to FIG.
17;
[0029] FIG. 19 is a diagram showing a task timetable according to another
embodiment of the present invention;
[0030] FIG. 20 is a timing diagram showing the order of operation of a task according
to FIG. 19 and FIG. 12;
[0031] FIG. 21 is a flow chart showing a method for changing work priority according
to another embodiment of the present invention;
[0032] FIG. 22 is a flow chart showing an example of the method for changing work
priority according to FIG. 21;
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[0033] FIG. 23 is a timing diagram showing the order of operation of a task whose
work priority has been changed by the method for changing work priority according to FIG.
22; and
[0034] FIG. 24 is a hardware configuration diagram of a battery management system
according to an embodiment of the present invention.
MODE FOR CARRYING OUT THE INVENTION
[0035] Hereinafter, various embodiments of the present invention will be described in
detail with reference to the accompanying drawings. In the present document, like
reference numerals are used for like elements throughout the drawings, and redundant
descriptors of the like elements are omitted.
[0036] For the various embodiments of the present invention disclosed in the present
document, specific structural to functional descriptions are merely illustrative of the
present invention. The various embodiments of the present invention may be embodied
in various forms and should not be construed as limited to the embodiments set forth
herein.
[0037] Terms such as “a first,” “a second,” “first,” and “second” used in various
embodiments may modify various components regardless of the order and/or importance
thereof, and do not limited the corresponding components. For example, a first
component may be referred to as a second component without departing from the scope of
the present invention, and similarly, a second component may also be referred to as a first
component.
[0038] The terms used in this document are only used to describe specific
embodiments, and may not be intended to limit the scope of other embodiments. Singular
expressions may include plural expressions unless the context clearly indicates otherwise.
[0039] FIG. 1 is a configuration diagram schematically showing a battery system
according to an embodiment of the present invention.
[0040] Referring to FIG. 1, a battery system according to the present invention may
include a battery module 10 including a cell module 12 having a plurality of battery cells, a
battery management system (hereinafter, referred to as ‘BMS’) 14, and a switching unit 16,
and a master BMS 20 for controlling and managing the battery module 10.
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[0041] The cell module 12 includes one or more chargeable/dischargeable battery cells.
The battery cell may be a lithium-ion (Li-ion) battery, a lithium-ion (Li-on) polymer
battery, a nickel-cadmium (Ni-Cd) battery, a nickel-hydrogen (Ni-MH) battery, and the like,
but is not limited thereto.
[0042] The BMS 14 may control the operation of the switching unit 16 to control the
charge/discharge of the cell module 12. In addition, the BMS 14 may monitor the cell
module 12 and/or the voltage, current, temperature, and the like of each battery cell
included in the cell module 12. In addition, for the monitoring by the BMS 14, a sensor
or various measurement modules not illustrated may be additionally installed at the cell
module 12, a charge/discharge path, or at any position of the cell module 12 and the like.
The BMS 14 may calculate a parameter indicating the state of the cell module 12, for
example, SOC, SOH, or the like, on the basis of measurement values of the monitored
voltage, current, temperature, and the like.
[0043] The BMS 14 controls and manages the overall operation of the battery module
10. To this end, the BMS 14 may include various components such as a mycom which is
a controller for executing programs and controlling the overall operation of the BMS 14,
input/output devices such as sensors and measurement means, and other peripheral circuits.
[0044] BMS 14 is capable of communicating with the master BMS 20 wirelessly, and
may transmit various measurement values of the monitored voltage, current, temperature,
and the like, or calculation values of SOC, SOH, or the like to the master BMS 20.
Particularly, the BMS 14 according to the present invention determines a work schedule
which is the order of performance of tasks to be performed in consideration of various
conditions. At this time, the various conditions may include work priority and
performance time of tasks, communication time required to transmit data to the master
BMS 20 or other BMSs, communication priority between the tasks and other BMSs, and
the like. The determination of the work schedule and change thereof will be described in
detail below.
[0045] The switching unit 16 is a semiconductor switching element for controlling
current flow for the charge/discharge of the cell module 12, and for example, at least one
MOSFET may be used.
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[0046] The battery module 10 may be provided in the form of the battery pack 1
including a plurality of the battery modules 10 according to the specifications of a device
on which the battery module 10 is to be mounted. In addition, the battery pack 1 may
include the master BMS 20 which controls and manages the battery module 10. The
master BMS 20 may receive various data from the BMS 14 included in each battery
module 10. The master BMS 20 may send to the BMS 14 included in each battery
module 10 a signal for controlling the same.
[0047] In addition, the master BMS 20 may have no battery module 10 to separately
manage. Alternatively, the master BMS 20 may be that any one BMS 14 included in each
of the plurality of battery modules 10 plays a role as a master communication device.
[0048] Meanwhile, the master BMS 20 may be communicatively connected to an
external higher-level controller 2. That is, the master BMS 20 of the battery pack 1 may
send various data on the battery pack 1 to the higher-level controller 2 and may receive a
control signal for the operation of the battery pack 1 from the higher-level controller 2.
When the battery pack 1 is mounted on an electric vehicle, the higher-level controller 2
may be a vehicle controller for controlling the driving of the vehicle.
[0049] FIG. 2 is a configuration diagram of a battery pack including a battery
management system according to an embodiment of the present invention.
[0050] Referring to FIG. 2, the battery pack 1 includes a plurality of battery modules
10-1 to 10-N (wherein N is an integer of 1 or greater) and the master BMS 20 which
controls and manages the same. The plurality of battery modules 10-1 to 10-N
respectively include corresponding BMSs 14-1 to 14-N.
[0051] The master BMS 20 and each of the BMSs 14-1 to 14-N communicate with
each other wirelessly.
[0052] The master BMS 20 is a control circuit of a battery module (battery module
controller) and may be responsible for communication with the higher-level controller 2.
However, when it is a small system without a higher-level controller, the master BMS 20
may be operated in an independent form without a higher-level controller.
[0053] The master BMS 20 uses various information obtainable from a sensor, such as
the current voltage, temperature, and humidity of the battery pack 1 or the battery module
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10 to perform various tasks to be performed by a BMS. The various tasks may include an
operation of obtaining the various information from the sensor.
[0054] The BMSs 14-1 to 14-N, which are cell module controllers, perform voltage
measurement, module voltage measurement, temperature measurement, humidity
measurement, resistance measurement, and the like for the cell module 12, and convert
information provided from the sensor through various measurements to fit the battery
system to transmit the converted information to the master BMS 20, which is the upper
control circuit.
[0055] In addition, the BMSs 14-1 to 14-N may perform corresponding operations
according to commands for performing various operations such as cell balancing
transmitted from the master BMS 20 or the higher-level controller 2.
[0056] As described above, the BMSs 14-1 to 14-N and the master BMS 20 which are
communication nodes connected wirelessly in the system share a task table, and may
perform some tasks by synchronizing time. However, when tasks are synchronized and
performed as described above, IDLE time occurs in individual nodes due to reasons such
as waiting for communication. As a result, the BMSs 14-1 to 14-N and the master BMS
20, which are nodes, cannot efficiently utilize their own resources, so that there is a
possibility in that work efficiency is lowered than when the performance time of tasks is
not synchronized. In addition, tasks which may be all processed if the performance time
of the tasks is not synchronized may not be processed within a predetermined period of
time.
[0057] Hereinafter, in order to solve the above problems, embodiments of the present
invention capable of reconsidering work efficiency by adding a work scheduler to the
BMSs 14-1 to 14-N and the master BMS 20 will be described. Specifically, the
configuration and operation of the BMSs 14-1 to 14-N and the master BMS 20 in a system
in which each of the plurality of BMSs 14-1 to 14-N and the master BMS 20 performs a
task individually set and results of the performed tasks are transmitted to the master BMS
20 via wireless communication will be described.
[0058] When designing a wireless network protocol, tasks of a system using the
corresponding protocol are already determined. In addition, due to the nature of an
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embedded system, all tasks which are determined should be performed within a
predetermined time, and should not exceed a predetermined maximum time.
[0059] In addition, the operation method of a micro-processor MUC and the like is a
sequential operation method according to work priority among tasks. The order is
determined at the time of design, and is not modified during Runtime. In addition, there
is idle time in a work schedule finally determined. When tasks are sequentially
performed without the synchronization of the tasks due to the performance of a
microprocessor, all the tasks may be performed within a predetermined time. However,
when tasks are synchronized and performed, there are cases in which all the tasks may not
be performed within a predetermined time.
[0060] The embodiments of the present invention have been made in view of the
above situation.
[0061] FIG. 3 is a functional block diagram showing the configuration of a battery
management system according to an embodiment of the present invention.
[0062] Referring to FIG. 3, a BMS 100 according to the present invention may include
a communication unit 110, a storage unit 120, a schedule determination unit 130, a priority
changing unit 140, a work performance unit 150, a synchronization unit 160, and an error
calculation unit 170. Here, the BMS 100 may be the BMS 14 which is a slave node or the
master BMS 20 which is a master node. Hereinafter, the BMS 14 which is a slave and the
master BMS 20 will all be referred to as the BMS 100.
[0063] The communication unit 110 transmits and receives data and various signals
with another BMS 100. That is, the communication unit 110 performs a function for the
communication with another slave BMS 14 and the master BMS 20. The communication
unit 110 may use various protocols such as wireless CAN communication, WIFI, Bluetooth,
and Zigbee with another slave BMS 14 and master BMS 20.
[0064] The communication unit 110 may transmit a list of tasks performed by the
same and the performance time, performance cycle, and work priority of each task
included in the list of tasks to another BMS 14 and the master BMS 20 to share a task
timetable with each other. In addition, the communication unit 110 may share a
communication priority table showing the communication priority between another slave
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BMS 14 and master BMS 20. That is, the communication unit 110 may transmit data on
the task timetable and the communication priority table to another BMS 100. In the same
manner, the communication unit 110 may receive data on the task timetable and the
communication priority table from another BMS 100.
[0065] In addition, the communication unit 110 may transmit results of a task
performed by the same to the master BMS 20 and the like. At this time, when the priority
of a work and accordingly the work schedule thereof have been changed by the priority
changing unit 140 while performing a task, the communication unit 110 may transmit the
corresponding changes to another BMS 100 to share the changes. In the same manner,
the communication unit 110 may receive changes to the priority of a task and the work
schedule thereof from another BMS 100.
[0066] The communication unit 110 may transmit signals and data in a multi-cast or
broadcast manner. For example, the communication unit 110 may transmit a work
schedule adjusted by the schedule determination unit 130 to another BMS 100 in a multicast or broadcast manner.
[0067] When meeting a predetermined condition, the communication unit 110 may
perform communication for sharing a task timetable and a communication priority table.
For example, when the system of a device on which the battery pack 1 is mounted wakes
up, the communication unit 110 may perform the communication for sharing a task
timetable and a communication priority table. When the device on which the battery pack
1 is mounted is an electric vehicle, the above condition may be starting the vehicle.
Alternatively, the communication unit 110 may periodically perform the communication
for sharing a task timetable and a communication priority table.
[0068] Furthermore, the communication unit 110 may receive the performance start
signal, performance completion signal, and the like of a task for synchronization with other
BMSs 100 at the time of performing the task.
[0069] The storage unit 120 stores various programs required for the operation of the
BMS 100 and various data generating when the BMS 100 is operated. The storage unit
120 may store a task timetable including a list of tasks performed by each of a plurality of
BMSs 100 in the battery pack 1 and the performance time, performance cycle, and work
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priority of each task included in the list of tasks. The storage unit 120 may store a
communication priority table showing the communication priority among the plurality of
BMSs 100 in the battery pack 1. Furthermore, the storage unit 120 may have tasks which
are set to be performed in synchronization with another BMS 100 in the task list. In
addition, when received the adjusted work schedule from another BMS 100 through the
communication unit 110, the storage unit 120 may update stored contents of the task
timetable, the communication priority table, and the like with the adjusted work schedule.
That is, the storage unit 120 serves a function as a task information storage unit.
[0070] The schedule determination unit 130 determines a work schedule on the basis
of stored data. Specifically, the schedule determination unit 130 determines the work
schedule on the basis of contents of the task timetable and the communication priority table,
which are data stored in the task information storage unit. The schedule determination
unit 130 also determines the work schedule in consideration of setting information on tasks
to be performed in synchronization with another BMS 100.
[0071] The work schedule refers to the order in which each task is performed and
when to start and end each task to be performed.
[0072] When there is a change to the work priority of some tasks by the priority
changing unit 140, the schedule determination unit 130 adjust the work schedule according
to the adjusted work priority.
[0073] The priority changing unit 140 adjusts the work priority of a task on the basis
of the work schedule determined by the schedule determination unit 130.
[0074] As an example, when there is a subordinated task which may be performed
during a waiting time in the work schedule determined by the schedule determination unit
130, the priority changing unit 140 adjusts the work priority of the corresponding
subordinated task to be after the work priority of a task to be performed just before the
waiting time. The waiting time may refer to a period of time from when a specific task is
performed before when results of the task are transmitted to another BMS 100. The
waiting time may refer to a period of time during which the processor utilization rate of the
corresponding BMS 100 is equal to or less than a reference value.
[0075] The priority changing unit 140 compares the length of the waiting time of the
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work schedule determined by the schedule determination unit 130 with the length of the
performance time of each task to be performed after the waiting time. The priority
changing unit 140 may perform the comparison of the waiting time and the performance
time on tasks stored in a task queue 125 to be described later. Alternatively, the priority
changing unit 140 may perform the comparison of the waiting time and the performance
time on tasks included in the entire determined work schedule.
[0076] In addition, the priority changing unit 140 adjusts the work priority such that a
task having a performance time shorter than the length of the waiting time is performed
during the waiting time. At this time, as an example, when there are a plurality of tasks
having a performance time shorter than the length of the waiting time, the priority
changing unit 140 may adjust the work priority of a task having the highest work priority
among the corresponding tasks. Alternatively, as another example, when there are a
plurality of tasks having a performance time shorter than the length of the waiting time, the
priority changing unit 140 may adjust the work priority of a task having the longest
performance time among the tasks.
[0077] When the priority of a work and accordingly the work schedule thereof have
been adjusted by the priority changing unit 140 as described above, the communication
unit 110 may transmit the corresponding changes to another BMS 100 to share the changes.
[0078] The work performance unit 150 performs tasks to be performed by the same
according to the work schedule determined by the schedule determination unit 130.
When there is a task to be performed in synchronization with another BMS 100, the work
performance unit 150 performs the task in synchronization. For example, for the
synchronization, with respect to the performance start time of each task, the work
performance unit 150 performs each task according to the start time thereof calculated by
the synchronization unit 160. Therefore, it is possible to synchronize the work
performance time with another BMS 100 which performs the same task.
[0079] The synchronization unit 160 uses the performance start signal and
performance completion signal of a specific task and the task timetable received from the
communication unit 110 to calculate the performance start time of the specific task. In
addition, the synchronization unit 160 synchronizes the performance time of the
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corresponding task of each BMS 100 through the calculated performance start time.
[0080] The error calculation unit 170 uses time at which the performance start signal
and performance completion signal of a specific task are received and the task timetable
received from the communication unit 110 to calculate an error. For example, the error
calculation unit 170 uses the difference in time at which the performance start signal of the
specific task is received and time at which the performance completion signal thereof is
received and the difference in performance time of the specific task on the task timetable to
calculate an error and provides the error to the synchronization unit 160. When
calculating the performance time of a first task, the synchronization unit 160 may reflect
the calculated error.
[0081] By determining a work schedule as described above and performing an
operation of changing the work priority of a task in the determined task schedule, the BMS
100 may efficiently utilize its own resources.
[0082] Hereinafter, a function of determining a work schedule and adjusting work
priority will be described in more detail.
[0083] FIG. 4 is a functional block diagram showing a work scheduler 200 in a battery
management system according to an embodiment of the present invention.
[0084] The work scheduler 200 has a function to determine a work schedule and
adjust work priority. The work scheduler 200 may include a task timetable 121, a
communication priority table 123, the task queue 125, and the priority changing unit 140.
[0085] In the task timetable 121, as described above, a list of tasks to be performed by
each BMS 100, which is a communication node, the order of the tasks, and the
performance time, (if necessary) communication time, and performance cycle of each task
are stored.
[0086] In the communication priority table 123, with respect to a task requiring
communication, the communication priority among the BMSs 100 which perform the
corresponding task is stored. The communication priority may be information allocated
by the master BMS 20 when each node first joins a wireless communication network.
[0087] On the basis of the task time table 121 and the communication priority table
123, the work scheduler 200 knows in advance the list of tasks to be performed by each
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BMS 100, which is a communication node, the order of the tasks, and the performance
timing of the tasks. At this time, the priority and order of performance of a task to be
performed are determined, and the performance time thereof is almost constant. In
addition, tasks typically have a structure to be performed repeatedly at a specific time
(cycle).
[0088] The task queue 125 uses information which the work scheduler 200 has to
identify a task to be performed on the basis of the work schedule determined by the
schedule determination unit 130. In addition, tasks to be performed are sequentially
called to be stored in the task queue 125.
[0089] As descried above, the priority changing unit 140 may adjust the work priority
of a task according to predetermined criteria. The priority changing unit 140 may adjust
the work priority recorded in the task timetable. Alternatively, the priority changing unit
140 may adjust the work priority of tasks included in the task queue 125 on the basis of the
determined task schedule to change the order in the task queue 125. That is, among tasks
excluding a task (a task currently being performed) having the highest work priority among
tasks included in the task queue 125, the priority changing unit 140 may change the work
priority of a task having a performance time shorter than a waiting time. When the task in
which the work priority has been changed is completed, the priority changing unit 140 may
change the work priority of the corresponding task back to the original work priority
thereof.
[0090] FIG. 5 is a flow chart showing the operation of a battery management system
according to an embodiment of the present invention.
[0091] Referring to FIG. 5, first, the BMS 100 shares a task timetable and a
communication priority table with another BMS S10. That is, through the communication
unit 110, data required for making a task timetable and a communication priority table is
transmitted to and received from another BMS 100.
[0092] The BMS 100 updates the task timetable and the communication priority table
by including the task timetable and the communication priority table received from another
BMS S11. That is, the BMS 100 generates a final task timetable 121 and a final
communication priority table 123 in consideration of both data of its own and data of
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another BMS. That is, in the storage unit 120 of the BMS 100, the list of tasks performed
by each of the plurality of BMSs 100 and the performance time, performance cycle, and
work priority of each task included in the list of tasks, and the communication priority
among the plurality of BMSs 100 may be stored in the form of the task timetable 121 and
the communication priority table 123.
[0093] In addition, a work schedule is determined on the basis of the updated tables
S12. That is, the work schedule is determined on the basis of data stored in the storage
unit 120.
[0094] FIG. 6 and FIG. 7 show the task timetable 121 and the communication priority
table 123 according to an embodiment of the present invention, which are stored in the
storage unit 120 on the basis of the method described with reference to FIG. 5.
[0095] In the present example, the master BMS 20, which is a master node, and the
BMSs 14-1 to 14-3, which are slave nodes, are included as communication nodes in a
wireless communication network. In addition, the task timetable 121 may include a task
list of each node, the priority among tasks included in the task list, the performance time
and communication time of each task, and the like. In addition, the total performance
time, which is the sum of work performance time and total communication time therefor,
and the cycle of each task may be additionally included. The communication priority
table 123 may include, with respect to a task requiring communication, the communication
priority among the BMSs 100 which perform the corresponding task for each task.
[0096] According to FIG. 6, the master BMS 20 performs Tasks A, B, and C, and a
BMS#1 14-1 performs Tasks A, B, and E. A BMS#2 14-2 performs Tasks A, B, and D,
and a BMS#3 14-3 performs Tasks A, E, and F.
[0097] In addition, according to FIG. 7, for Task A, communication priority is given in
the order of BMS#1 -> BMS#2 -> BMS#3 -> the master BMS. For Task B,
communication priority is given in the order of BMS#1 -> BMS#2 -> the master BMS.
[0098] FIG. 8 is a flow chart showing a work scheduling operation of a battery
management system according to an embodiment of the present invention.
[0099] Referring to FIG. 8, as described with reference to FIG. 5, when the task
timetable 121 and the communication priority table 123 are generated and stored, a work
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schedule is determined by the schedule determination unit 130. In addition, on the basis
of the determined work schedule, tasks to be performed are sequentially stored in the task
queue 125 S20.
[00100] Thereafter, whether it is possible to process all the tasks stored in the task
queue 125 within a predetermined period of time, that is a cycle, is determined S21. If it
is possible to process all the tasks within the predetermined period of time, (Yes in S21),
the tasks are processed in the order of the task queue S23. That is, the tasks are
processed according to the determined work schedule without the change in work priority.
[00101] On the other hand, if it is not possible to process all the tasks within the
predetermined period of time, (No in S21), the work priority thereof is changed S22.
Thereafter, the order of the task queue is changed on the basis of the changed work priority,
and the tasks are processed in the order of the changed task queue S23.
[00102] That is, on the basis of the determined work schedule, when the tasks meet
predetermined conditions, the work priority of the tasks is adjusted, and according to the
adjusted work priority, the work schedule is adjusted.
[00103] FIG. 9 is a timing diagram showing the order of operation of a task on the basis
of the task timetable 121 and the communication priority table 123 according to FIG. 6 and
FIG. 7. FIG. 9 may illustrate the state of a task queue while including communication
time and a waiting period of time between tasks.
[00104] Referring to FIG. 9, A to F show a period of time during which each task is
performed. 1 to 3 indicate a communication period of time during which each node
transmits data to the master BMS 20, and the Chinese character ‘上’ indicates a
communication period of time during which the master BMS 20 transmits data to the
higher-level controller 2. The hatching mark indicates the waiting time.
[00105] The master BMS 20 performs Task A in synchronization with another node for
0 to 30 ms. Thereafter, for 30 to 45 ms, the master BMS 20 sequentially receives data
such as result information on Task A from the BMS#1 14-1 to the BMS#3 14-3. In
addition, finally, the master BMS 20 transmits data on Task A to the higher-level controller
for 45 to 50 ms. In the same manner, the master BMS 20 sequentially performs
performance and communication for Task B, and becomes in a standby state for 80 to 100
18
ms after performing Task C.
[00106] The BMS#1 14-1 performs Task A in synchronization with another node for 0
to 30 ms. Thereafter, for 30 to 35 ms, the BMS#1 14-1 transmits data such as result
information on Task A to the master BMS 20. The BMS#1 14-1 becomes in a standby
state for 35 to 50 ms, and then performs Task B in synchronization for 50 to 60 ms. After
performing Task B, the BMS#1 14-1 transmits data such as result information on Task C to
the master BMS 20 for 60 to 65 ms. Finally, the BMS#1 14-1 performs Task E for 65 to
85 ms, and becomes in a standby state for the remaining period of time.
[00107] The BMS#2 14-2 performs Task A in synchronization with another node for 0
to 30 ms. Thereafter, the BMS#2 14-2 becomes in a standby state for 30 to 35 ms, and
for 35 to 40 ms, the BMS#2 14-2 transmits data such as result information on Task A to the
master BMS 20. The BMS#2 14-2 becomes in a standby state again for 40 to 50 ms, and
performs Task B in synchronization for 50 to 60 ms. After performing Task B, the
BMS#2 14-2 becomes in a standby state for 60 to 65 ms, and transmits data such as result
information on Task C to the master BMS 20 for 65 to 70 ms. Finally, the BMS#2 14-2
performs Task D for 70 to 75 ms, and becomes in a standby state for the remaining period
of time.
[00108] Lastly, the BMS#3 14-3 also performs Task A in synchronization with another
node for 0 to 30 ms. Thereafter, the BMS#3 14-3 becomes in a standby state for 30 to 40
ms, and for 40 to 45 ms, the BMS#3 14-3 transmits data such as result information on Task
A to the master BMS 20. Since the BMS#3 14-3 does not include Task B, the BMS#3 14-
3 performs Task E for 45 to 65 ms, and then performs Task F for 65 to 80 ms. Finally, the
BMS#3 14-3 becomes in a standby state for 80 to 100 ms, which is the remaining period of
time.
[00109] As can be seen in FIG. 9, in the case of the work schedule on the basis of the
task timetable 121 and the communication priority table 123 according to FIG. 6 and FIG.
7, there is no problem in performing everything on the schedule within a cycle of 100 ms,
which is a predetermined period of time.
[00110] However, if necessary, it may be desirable to change the work priority of tasks
for the efficient operation of a microprocessor and the like. FIG. 10 is a timing diagram
19
showing the order of operation of a task whose work priority has been changed by a battery
management system according to an embodiment of the present invention.
[00111] As can be seen in the task timetable 121 and the communication priority table
123 of FIG. 6 and FIG. 7, Task D of the BMS#2 14-2 does not need to be performed in
synchronization with another node. In addition, as can be seen in FIG. 9, the BMS#2 14-
2 has a waiting time of 30 to 35 ms. Therefore, as can be seen in the timing diagram of
the BMS#2 14-2 of FIG. 10, the work priority of Task D may be adjusted to be prior to the
work priority of Task B such that Task D may be performed during the waiting time of 30
to 35 ms. To this end, in the task queue, the work priority of Task D may be temporarily
adjusted to be prior to the work priority of Task B, and after the completion of performing
the tasks, the work priority of the tasks may be adjusted back to the original work priority
thereof. Alternatively, in order to allow the work priority of Task D to be prior to the
work priority of Task B in the task timetable 121, the table itself may be updated.
[00112] FIG. 11 and FIG. 12 are diagrams showing the task timetable 121 and the
communication priority table 123 according to another embodiment of the present
invention. In the present embodiment, all nodes include both Task A and Task B, and are
set to perform the same in synchronization.
[00113] According to FIG. 11, the master BMS 20 performs Tasks A, B, and C, and the
BMS#1 14-1 performs Tasks A, B, F, G, and H. The BMS#2 14-2 and the BMS#3 14-3
each perform Tasks A, B, D, and E.
[00114] In addition, according to FIG. 12, for both Tasks A and B, communication
priority is given in the order of BMS#1 -> BMS#2 -> BMS#3 -> the master BMS.
[00115] Hereinafter, a method for adjusting work priority and a work schedule on the
basis of the tables of FIG. 11 and FIG. 12 will be described.
[00116] FIG. 13 is a timing diagram showing the order of operation of a task according
to FIG. 11 and FIG. 12.
[00117] Referring to FIG. 13, it can be seen that the BMS#1 14-1 and the BMS#3 14-3
do not complete all the tasks within a predetermined period of time (for example, a cycle
of 100 ms). That is, Task H and Task E are terminated over 100 ms. This is a situation
in which an error has occurred in the battery system, and typically, some tasks have to be
20
removed in order to solve the problem. Alternatively, in order to solve the problem, the
task timetable 121 and the communication priority table 123 had to be directly modified in
its entirety.
[00118] However, in the embodiments of the present invention, the above problem may
be solved in the following manner.
[00119] FIG. 14 is a flow chart showing a method for changing work priority according
to an embodiment of the present invention. This operation corresponds to the detailed
operation of changing the work priority described with reference to S22 of FIG. 8.
[00120] Referring to FIG. 14, firstly, a waiting time on the determined work schedule is
calculated S100. This may be a portion indicated by hatching in FIG. 13. In addition,
the waiting time and the performance time of tasks in the task queue are compared S101.
[00121] For example, as can be seen in FIG. 13, in the case of the BMS#1 14-1, a
period of time of 15 ms during the waiting time of 35 to 50 ms and the performance time
of Tasks F, G and H which do not need to be performed in synchronization among tasks
after the waiting time are compared. In the case of the BMS#3 14-3, 10 ms between 40 to
50 ms, which is the waiting time, 5 ms between 55 to 60 ms, and 10 ms between 70 to 80
ms and the performance time of Tasks D and E which do not need to be performed in
synchronization among tasks after the waiting time are compared.
[00122] Whether there is a task whose performance time is equal to or less than the
waiting time among the tasks whose performance time has been compared is determined
S102, and if it is determined that there is a task whose performance time is equal to or less
than the waiting time, the work priority of the corresponding task is changed S103.
[00123] That is, when there is a subordinated task which may be performed during the
waiting time of the determined work schedule, the work priority of the corresponding
subordinated task may be adjusted to be after the work priority of a task to be performed
just before the waiting time.
[00124] On the other hand, if it is determined that there is no task whose performance
time is equal to or less than the waiting time, it is determined that it is impossible to correct
an error, and thus, the error is notified to the higher-level controller 2 and the like S104.
[00125] FIG. 15 is a flow chart showing an example of a method for changing work
21
priority according to an embodiment of the present invention. This operation corresponds
to the detailed operation of changing the work priority described with reference to S103 of
FIG. 15. FIG. 16 is a timing diagram showing the order of operation of a task whose
work priority has been changed by the method for changing work priority according to FIG.
15.
[00126] Referring to FIG. 15, firstly, whether there are a plurality of tasks having a
performance time shorter than the length of a waiting time is determined S200. When
there are a plurality of tasks having a performance time shorter than the length of a waiting
time (Yes in S200), the work priority of a task having the highest work priority among the
corresponding tasks is adjusted.
[00127] As can be seen in FIG. 16, Tasks F, G and H of BMS#1 14-1 have a
performance time shorter than a waiting time of 15 ms long in 45 to 60 ms. In addition,
Task F has the highest work priority. Therefore, the work priority is adjusted such that
Task F is first performed during the waiting time of 45 to 50 ms. Even thereafter, a
waiting time of 10 ms long in 50 to 60 ms remains, and since Task H has a performance
time of 10 ms, the work priority is adjusted such that Task H is performed during the
corresponding waiting time. In addition, with the adjustment of the work priority, Task G
may perform tasks for a duration between 75 and 90 ms with a schedule which is 5 ms
ahead of the previous one.
[00128] Also, in the case of BMS#3 14-3, the work priority is first adjusted such that
Task D having the highest work priority is performed during a waiting time of 40 to 50 ms,
and the work priority is adjusted such that Task E is performed during a waiting time of 70
to 80 ms.
[00129] In addition, although the BMS#2 14-2 is capable of processing all the tasks
within the predetermined period of time, the work priority of Task D may be adjusted for
the efficient operation of a microprocessor. However, in the case of Task E, only the
work schedule is adjusted. That is, in the case of Task E, the work priority thereof is not
adjusted. Only the start and end timing thereof are adjusted.
[00130] Meanwhile, when there is one task having a performance time shorter than the
length of a waiting time (No in S200), the work priority of the corresponding task is
22
adjusted.
[00131] FIG. 17 is a flow chart showing another example of a method for changing
work priority according to an embodiment of the present invention. This operation
corresponds to another detailed operation of changing the work priority described with
reference to S103 of FIG. 15. FIG. 18 is a timing diagram showing the order of operation
of a task whose work priority has been changed by the method for changing work priority
according to FIG. 17.
[00132] Referring to FIG. 17, S300 and S302 are the same as S200 and S202 of FIG. 15.
[00133] On the other hand, when there are a plurality of tasks having a performance
time shorter than the length of the waiting time, in the present embodiment, the work
priority of a task having the longest performance time among the corresponding tasks is
adjusted S201.
[00134] As can be seen in FIG. 18, Tasks F, G and H of BMS#1 14-1 have a
performance time shorter than a waiting time of 15 ms long in 45 to 60 ms. In addition,
Task G has the longest performance time. Therefore, the work priority is adjusted such
that Task G is first performed during the waiting time of 45 to 50 ms. Thereafter, a
waiting time of 80 to 95 ms, which is time during which Task G performs a task, remains,
and the work priority is adjusted such that Task H is performed for 80 to 90 ms. However,
in the case of Task G, the work priority thereof is not adjusted. Only the start and end
timing thereof are adjusted.
[00135] In the cases of the BMS#2 14-2 and the BMS#3 14-3, Task D and Task E have
the same performance time after the waiting time, so that the work priority and the work
schedule are adjusted as in the example of FIG. 15 and FIG. 16.
[00136] As described above, by allowing the priority to be arbitrarily adjusted among
tasks performed after the waiting time, it is possible to process tasks which typically have
not been all processed within a predetermined period of time, so that it is possible to
efficiently operate hardware.
[00137] FIG. 19 is a diagram showing a task timetable according to another
embodiment of the present invention.
[00138] According to FIG. 19, the master BMS 20 performs Tasks A, B, and C, and the
23
BMS#1 14-1 performs Tasks A, B, F, and G. The BMS#2 14-2 and the BMS#3 14-3 each
perform Tasks A, B, D, and E. In the present embodiment, communication priority is as
shown in FIG. 12.
[00139] FIG. 20 is a timing diagram showing the order of operation of a task according
to FIG. 19 and FIG. 12.
[00140] Referring to FIG. 20, it can be seen that the BMS#1 14-1 and the BMS#3 14-3
do not complete all the tasks within a predetermined period of time (for example, a cycle
of 100 ms). That is, Task G and Task E are terminated over 100 ms. This is a situation
in which an error has occurred in the battery system, and typically, some tasks have to be
removed in order to solve the problem. Alternatively, in order to solve the problem, the
task timetable 121 and the communication priority table 123 had to be directly modified in
its entirety.
[00141] However, in the embodiments of the present invention, the above problem may
be solved in the following manner which is different to the above-described manner.
[00142] FIG. 21 is a flow chart showing a method for changing work priority according
to another embodiment of the present invention. This operation corresponds to another
detailed operation of changing the work priority described with reference to S22 of FIG. 8.
[00143] Referring to FIG. 21, the operations of S400 to S403 are the same as the
operations of S100 to S103 of FIG. 14. That is, if it is possible to process all the tasks
within a cycle, the tasks are performed according to the determined work schedule. In
addition, if it is not possible to process all the tasks within a cycle and there is a task
having a performance time shorter than a waiting time, the work priority of the
corresponding task is adjusted to allow all the tasks to be processed within the cycle.
[00144] On the other hand, when there is no task having a performance time shorter
than a waiting time (No in S402), whether it is possible to divide the task is determined
S404.
[00145] FIG. 22 is a flow chart showing an example of the method for changing work
priority according to FIG. 21.
[00146] Referring to FIG. 22, since a task having a performance time shorter than a
waiting time is not included in a task queue, it is necessary to devise another method to
24
process tasks within a cycle. To this end, whether there is a task which may be divided
and performed among tasks included in the task queue is determined S500.
[00147] When there is a task which may be divided and performed (Yes in S500), the
corresponding task is divided into a plurality of sub-tasks. At this time, the performance
time of at least one sub-task is set to be equal to or less than a waiting time S501.
[00148] Thereafter, the work priority of the sub-task divided to have a performance
time equal to or less than the waiting time is changed S502. Therefore, by allowing the
sub-task to be performed during the waiting time, it is possible to process all the tasks
within a predetermined period of time.
[00149] Meanwhile, when there is no task which may be divided and performed among
tasks included in the task queue, it is not possible to process all the tasks within the
predetermined period of time, so that an error is notified to the higher-level controller 2
and the like S503.
[00150] FIG. 23 is a timing diagram showing the order of operation of a task whose
work priority has been changed by the method for changing work priority according to FIG.
22.
[00151] As can be seen in FIG. 23, the BMS#1 14-1 is performed after a waiting time,
and it is possible to divide Task F between Tasks F and G which do not need to be
performed in synchronization. Task F may be divided into two tasks of Sub-tasks f1 and
f2. In the present embodiment, both f1 and f2 have a performance time equal to or less
than the waiting time. However, it is also possible that only at least one sub-task has a
performance time equal to or less than the waiting time. At this time, the at least one subtask may be divided to have a performance time of the same length as the waiting time.
That is, Sub-task f1 is divided to have a performance time of 15 ms so as to be performed
for 45 to 60 ms, which is the waiting time of the BMS#1 14-1. In addition, Sub-task f2 is
generated having a performance time of 5 ms for the remainder. The work priority of
Sub-task f1 is adjusted to be performed before Task B, and thus, a task is performed for 45
to 60 ms, which is the waiting time. As a result, a task of a length exceeding the
predetermined period of time may be performed during the waiting time, so that it is
possible to perform all the tasks within the predetermined period of time.
25
[00152] FIG. 24 is a hardware configuration diagram of a battery management system
according to an embodiment of the present invention.
[00153] Referring to FIG. 24, a BMS 400 may include a controller (MCU) 410, a
memory 420, an input/output interface 430, and a communication interface 440.
[00154] The MCU 410 controls various operations, calculation processing, and each
component in the BMS 400.
[00155] The memory 420 stores an operating system program and a program for
performing the function of the BMS 400. The memory 420 may include a volatile
memory and/or a non-volatile memory. For example, as the memory 420, at least one of
various storage media such as a semiconductor memory such as a RAM, a ROM, and a
flash memory, a magnetic disk, and an optical disk may be used.
[00156] The input/output interface 430 performs the input and output of various input
signals and output signals. For example, the MCU 410 may output a control signal for
the switching operation of a switching element through the input/output interface 430.
[00157] The communication interface 440 is a component capable of communicating
with the outside in a wired and/or wireless manner.
[00158] The MCU 410 may execute the program stored in the memory 420 to
implement a module for performing the functions of the schedule determination unit 130,
the priority changing unit 140, the work performance unit 150, the synchronization unit
160, and the error calculation unit 170.
[00159] In addition, the MCU 410 may perform the function of the communication unit
110 in cooperation with the communication interface 440.
[00160] In the above, all the components constituting the embodiments of the present
invention have been described as being combined into one or combined to operate as one,
but the present invention is not necessarily limited to these embodiments. That is, if
within the scope of the present invention, all the components maybe selectively combined
into one or more to operate.
[00161] In addition, the terms “include,” “consist,” or “have” as described above mean
that a corresponding component may be intrinsic, unless specifically stated otherwise, and
it should interpreted as including other components rather than excluding other
26
components. All terms including technical or scientific terms may be interpreted as
having the same meanings as those commonly understood by those skilled in the art to
which the present invention pertains, unless defined otherwise. Terms commonly used as
those defined in a commonly used dictionary should be construed as being consistent with
the context of the relevant art, and are not to be construed in an idealized or overly formal
sense unless expressly defined in the present invention.
[00162] The above description is merely illustrative of the technical idea of the present
invention, and those skilled in the art to which the present invention pertains may make
various modifications and variations without departing from the essential characteristics of
the present invention. Therefore, the embodiments disclosed in the present invention are
not intended to limit the technical spirit of the present invention, but to explain, and the
scope of the technical spirit of the present invention is not limited by these embodiments.
The scope of protection of the present invention should be construed by the following
claims, and all technical concepts within the scope of the present invention should be
construed as being included within the scope of the rights of present invention.
27
CLAIMS
1. A battery management system in which each of a plurality of battery
management systems performs a task individually set and transmits results of the
performed tasks to a master battery management system via wireless communication, the
battery management system comprising:
a task information storage unit including a list of tasks performed by each of the
plurality of battery management systems, the performance time, performance cycle, and
work priority of each task included in the list of tasks, and the communication priority
among the plurality of battery management systems;
a schedule determination unit configured to determine a work schedule on the
basis of data stored in the task information storage unit; and
a priority changing unit configured to determine the work priority of a task based
on the basis of the work schedule determined by the schedule determination unit,
wherein the schedule determination unit is further configured to adjust the work
schedule according to the adjusted work priority.
2. The battery management system of claim 1, wherein, when there is a
subordinated task which is able to be performed during a waiting time in the work schedule
determined by the schedule determination unit, the priority changing unit is further
configured to adjust the work priority of the subordinated task to be after the work priority
of a task to be performed just before the waiting time.
3. The battery management system of claim 2, wherein the priority changing
unit is further configured to compare the length of the waiting time of the work schedule
determined by the schedule determination unit with the length of the performance time of
each task to be performed after the waiting time.
4. The battery management system of claim 3, wherein the priority changing
unit is further configured to adjust, after the comparison, the work priority such that a task
28
having a performance time shorter than the length of the waiting time is performed during
the waiting time.
5. The battery management system of claim 4, wherein when there is a
plurality of tasks having a performance time shorter than the length of the waiting time, the
priority changing unit is further configured to adjust the work priority of a task having the
highest work priority among the corresponding tasks.
6. The battery management system of claim 4, wherein when there is a
plurality of tasks having a performance time shorter than the length of the waiting time, the
priority changing unit is further configured to adjust the work priority of a task having the
longest performance time among the tasks.
7. The battery management system of claim 1, wherein the task information
storage unit has tasks which are set to be performed in synchronization with another
battery management system in the task list.
8. The battery management system of claim 7, wherein the schedule
determination unit is further configured to determine the work schedule in consideration of
the tasks to be performed in synchronization.
9. The battery management system of claim 7, wherein in the task list, a task
commonly performed by the plurality of battery management systems is performed in
synchronization.
10. The battery management system of claim 2, wherein the waiting time is a
period of time from when a specific task is performed before when results of the task are
transmitted to another battery management system.
11. The battery management system of claim 1, further comprising a
29
communication unit configured to communicate with the master battery management
system or another battery management system.
12. The battery management system of claim 11, wherein when the work
priority of a task has been adjusted by the priority changing unit, the communication unit is
further configured to transmit the work schedule adjusted by the schedule determination
unit to another battery management system.
13. The battery management system of claim 11, wherein when the adjusted
work schedule is received from the master battery management system or another battery
management system through the communication unit, stored contents of the task
information storage unit are updated with the adjusted work schedule.
14. The battery management system of claim 11, wherein the communication
unit is further configured to transmit the work schedule adjusted by the schedule
determination unit to another battery management system in a multi-cast or broadcast
manner.
15. The battery management system of claim 1, further comprising a task
queue configured to store tasks called based on the work schedule determined by the
schedule determination unit,
wherein the priority changing unit is further configured to change the work priority
of a task having a performance time shorter than a waiting time among tasks excluding a
task having the highest work priority among tasks included in the task queue.
16. The battery management system of claim 15, wherein when the task in
which the work priority has been changed is completed, the priority changing unit is
further configured to change the work priority of the corresponding task back to the
original work priority thereof.
30
17. A control method of a battery management system, the method
comprising:
storing a list of tasks performed by each of a plurality of battery management
systems, the performance time, performance cycle, and work priority of each task included
in the list of tasks, and the communication priority among the plurality of battery
management systems;
determining a work schedule based on the stored data;
adjusting the work priority of a task based on the determined work schedule; and
adjusting the work schedule according to the adjusted work priority.
18. The method of claim 17, wherein the adjusting the work priority of a task
is performed by adjusting, when there is a subordinated task which is able to be performed
during a waiting time in the determined work schedule, the work priority of the
subordinated task being after the work priority of a task to be performed just before the
waiting time.
19. The method of claim 18, wherein when there is a plurality of tasks having
a performance time shorter than the length of the waiting time, the work priority of a task
having the highest work priority among the corresponding tasks is adjusted.
20. The method of claim 18, wherein when there is a plurality of tasks having
a performance time shorter than the length of the waiting time, the work priority of a task
having the longest performance time among the tasks is adjusted.