U.S. patent application number 13/661504 was filed with the patent office on 2013-05-02 for modular battery control system architecture.
This patent application is currently assigned to EETREX, INC.. The applicant listed for this patent is Eetrex, Inc.. Invention is credited to Andrew Gaylo, Dennis L. Potts.
Application Number | 20130108898 13/661504 |
Document ID | / |
Family ID | 48171718 |
Filed Date | 2013-05-02 |
United States Patent
Application |
20130108898 |
Kind Code |
A1 |
Potts; Dennis L. ; et
al. |
May 2, 2013 |
MODULAR BATTERY CONTROL SYSTEM ARCHITECTURE
Abstract
Implementations of the present disclosure involve a battery
management architecture for a battery system involving a plurality
of connected power units. In general, the BMS comprises one or more
management sub-controllers connected serially to a master
controller associated with the powered device. Each of the one or
more management sub-controllers may be associated with a power unit
of the battery, with each power unit included one or more battery
modules or battery cells. Each of the one or more management
sub-controllers in the BMS share a communication link to provide
and receive information and instructions associated with the
battery system. In general, the BMS of the present disclosure
provides flexibility and modularity to the architecture of battery
systems for customization of the battery system for a variety of
uses and environments.
Inventors: |
Potts; Dennis L.; (Boulder,
CO) ; Gaylo; Andrew; (Westminster, CO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Eetrex, Inc.; |
Boulder |
CO |
US |
|
|
Assignee: |
EETREX, INC.
Boulder
CO
|
Family ID: |
48171718 |
Appl. No.: |
13/661504 |
Filed: |
October 26, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61551770 |
Oct 26, 2011 |
|
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Current U.S.
Class: |
429/50 ; 429/61;
429/90 |
Current CPC
Class: |
H01M 2010/4271 20130101;
Y02E 60/10 20130101; H01M 10/4207 20130101; Y02T 10/70 20130101;
H02J 7/0016 20130101; H02J 7/0013 20130101 |
Class at
Publication: |
429/50 ; 429/61;
429/90 |
International
Class: |
H01M 2/00 20060101
H01M002/00; H01M 10/48 20060101 H01M010/48 |
Claims
1. A battery management system comprising: a controller comprising:
a processing device configured to transmit and receive one or more
control signals for configuring a battery system; a downstream
communication link; and an upstream communication link; a first
sub-controller connected to the downstream communication link and
the upstream communication link of the controller, wherein the
first sub-controller is configured to receive one or more first
power unit control signals from a controller on the downstream
communication link and, in response to the one or more first power
unit control signals received from the controller, configure a
first plurality of battery cells in response; and a second
sub-controller connected to the first sub-controller and configured
to receive one or more second power unit control signals from the
first sub-controller and, in response to the one or more second
power unit control signals received from the first sub-controller,
configure a second plurality of battery cells.
2. The battery management system of claim 1 wherein the first
sub-controller further comprises: a first sub-controller processing
device configured to receive operational information from the first
plurality of battery cells; and a first sub-controller
computer-readable storage device configured to store operational
information of the first plurality of battery cells.
3. The battery management system of claim 2 wherein, in response to
the one or more first power unit control signals received from the
controller, the first sub-controller processing device operates to
transmit the stored operational information to the controller on
the upstream link.
4. The battery management system of claim 2 wherein the first
sub-controller computer-readable storage device is further
configured to store the one or more second power unit control
signals received from the controller and the first sub-controller
processing device operates to transmit the second power unit
control signals to the second power unit.
5. The battery management system of claim 2 wherein the first
sub-controller further comprises a power supply configured to
receive a power enable signal and provide power to the first
sub-controller processing device in response to receiving the power
enable signal.
6. The battery management system of claim 1 wherein a first portion
of the first plurality of battery cells are connected into a first
battery module and a second portion of the first plurality of
battery cells are connected into a second battery module, and
wherein further the first battery module and the second battery
module are serially connected to the first sub-controller.
7. The battery management system of claim 6 wherein configuring the
first plurality of battery cells in response the first control
signal comprises performing a balancing of the voltages of the
first battery module and the second battery module.
8. The battery management system of claim 1 wherein the first
plurality of battery cells comprises at least one battery cell of a
first chemical composition and at least one battery cell of a
second chemical composition.
9. The battery management system of claim 1 wherein the second
power unit is electrically isolated from the first power unit.
10. The battery management system of claim 1 further comprising: a
plurality of additional sub-controllers associated with the second
sub-controller and comprising: a plurality sub-controller
processing device configured to receive a plurality of power unit
control signals from the second power unit and, in response to the
plurality of power unit control signals received from the second
sub-controller, configure a plurality of battery cells; and a
plurality of sub-controller computer-readable storage devices
configured to store operational information of the first plurality
of battery cells.
11. A method for control of a battery system comprising a plurality
of power units, the method comprising: receiving a first control
signal from a controller on a first downstream communication link
at a first management control sub-controller associated with a
first power unit of the battery system, the first management
control sub-controller connected to the controller by the first
downstream communication link; configuring at least one setting of
the first power unit in response to the received first control
signal; receiving at least one performance indicator from the first
power unit; storing the at least one performance indicator of the
first power unit in a computer-readable storage device associated
with the first management control sub-controller; and transmitting
a second control signal on a second downstream communication link
to a second management control sub-controller associated with a
second power unit of the battery, wherein the second control signal
is substantially similar to the first control signal.
12. The method of claim 11 further comprising: receiving a second
power unit performance measurement on an upstream communication
link configured between the first power unit and the second power
unit; and storing the second power unit performance measurement in
the computer-readable medium.
13. The method of claim 12 further comprising: receiving a third
control signal from the controller on the first downstream
communication link at the first management control sub-controller
associated with the first power unit of the battery, the third
control signal comprising a request for the second power unit
performance measurement; and transmitting the second power unit
performance measurement on a first upstream communication link
configured between the first power unit and the controller.
14. The method of claim 11 wherein the first control signal
comprises an instruction to the first management control
sub-controller associated with the first power unit to perform a
balancing of a plurality of battery modules associated with the
first power unit.
15. The method of claim 11 wherein the first control signal
comprises a power enable signal to provide power to the first
management control sub-controller of the first power unit.
16. The method of claim 11 wherein the first control signal
comprises an initialization command and a first address value and
wherein the configuring operation comprises: retrieving the first
address value from the first control signal; and storing the first
address value in an address register associated with the first
power unit.
17. The method of claim 16 wherein the second control signal
comprises the initialization command and a second address value,
the second address value an increment of one from the first address
value.
18. A management sub-controller of a power unit of a battery system
comprising: a processor; a downstream communication receiver
configured to receive one or more control signals from a downstream
communication link; an upstream communication transmitter
configured to transmit one or more control signals on an upstream
communication link, wherein the downstream communication receiver
and upstream communication transmitter are electrically isolated
from the corresponding downstream link and upstream link; and a
computer-readable device with instructions stored thereon that,
when executed, cause the processor to perform the operations of:
obtaining at least one performance indicator of the power unit of
the battery system; storing the at least one performance indicator
in the computer-readable device; and transmitting the at least one
performance indicator to the upstream communication transmitter for
transmission on the upstream communication link.
19. The management sub-controller of claim 18 wherein the
downstream communication receiver is a wired electrically isolated
receiver and the transmitter is a wired electrically isolated
transmitter.
20. The management sub-controller of claim 18 wherein the
downstream communication receiver is an optical receiver and the
transmitter is an optical transmitter.
Description
RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application 61/551,770 filed on Oct. 26, 2011, the entirety of
which is incorporated herein by reference.
TECHNICAL FIELD
[0002] Aspects of the present disclosure generally relate to a
battery management system for a complex battery system. More
particularly, aspects of the present disclosure relate to a modular
battery system architecture and method for control of the same.
BACKGROUND
[0003] Larger and evermore complex battery systems are being
developed to provide larger voltages, more power, and larger
capacity for modern uses, such as in electric vehicles, hybrid
vehicles, home power supplies, and power storage for alternative
energy generation platforms such as wind and solar. Such systems
sometimes include several battery units interconnected in some
manner to provide the large voltage and power. For example, complex
battery systems may include several lower voltage battery packs
that, when combined in series, provide a higher voltage.
[0004] It is with these issues in mind, among others, that aspects
of the present disclosure were conceived and developed.
SUMMARY
[0005] Aspects of the present disclosure involve a battery
management system. The system includes a controller involving a
processing device configured to transmit and receive one or more
control signals for configuring a battery system, a downstream
communication link, and an upstream communication link. The system
further includes a first sub-controller connected to the downstream
communication link and the upstream communication link of the
controller. The first sub-controller is configured to receive one
or more first power unit control signals from a controller on the
downstream communication link and, in response to the one or more
first power unit control signals received from the controller,
configure a first plurality of battery cells in response. The
system further includes a second sub-controller connected to the
first sub-controller and configured to receive one or more second
power unit control signals from the first sub-controller and, in
response to the one or more second power unit control signals
received from the first sub-controller, configure a second
plurality of battery cells.
[0006] Aspects of the present disclosure further involve a method
for controlling a battery system comprising a plurality of power
units. The method includes the operation of receiving a first
control signal from a controller on a first downstream
communication link at a first management control sub-controller
associated with a first power unit of the battery system where the
first management control sub-controller is connected to the
controller by the first downstream communication link. The method
further includes the operation of configuring at least one setting
of the first power unit in response to the received first control
signal and receiving at least one performance indicator from the
first power unit. Additionally, the method includes the operation
of storing the at least one performance indicator of the first
power unit in a computer-readable storage device associated with
the first management control sub-controller. Finally, the method
involves the operation of transmitting a second control signal on a
second downstream communication link to a second management control
sub-controller associated with a second power unit of the battery
where the second control signal is substantially similar to the
first control signal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a block diagram illustrating a complex battery
system architecture, including a battery management system
providing modularity to the battery system.
[0008] FIG. 2 is a block diagram illustrating the communication and
power links between the components of the battery management system
of FIG. 1.
[0009] FIG. 3 is diagram illustrating an exemplary communication
flow between the components of the battery management system of
FIG. 1.
[0010] FIG. 4 is a block diagram illustrating a controller of a
battery management system for the complex battery system of FIG.
1.
[0011] FIG. 5 is a block diagram illustrating a battery management
system sub-controller for a complex battery system of FIG. 1
including electrical isolation on inputs to the sub-controller.
DETAILED DESCRIPTION
[0012] Aspects of the present disclosure involve a battery
management architecture for a battery system involving a plurality
of connected power units, with each power unit associated with one
or more battery cells. The battery management system (BMS) provides
modularity within the battery system for ease of expansion and cell
replacement, among other advantages. Further, the BMS also provides
the battery system independence from cell or pack voltages, charge
and discharge currents, system capacity or battery chemistry. In
general, the BMS comprises one or more management sub-controllers
connected to a master controller. Each of the one or more
management sub-controllers may be associated with a power unit of
the overall battery, with each power unit including one or more
battery modules or battery cells. Each of the one or more
management sub-controllers in the BMS share a communication link to
provide and receive information and instructions associated with
the complex battery system. In one embodiment, the shared
information and instructions may facilitate charging, charge
balancing, load balancing, discharge, cell replacement, module
replacement, pack replacement and other functions to ensure proper
battery function and longevity. In general, the BMS of the present
disclosure provides flexibility and modularity for customization of
the complex battery system for a variety of uses and
environments.
[0013] FIG. 1 is a block diagram illustrating one embodiment of a
battery system architecture 100, including a battery management
system providing modularity to the battery system. The battery
system 100 shown may be used in any environment or device where a
large voltage, stored electricity or power is needed. For example,
the battery system shown may be utilized in a hybrid vehicle, or an
electric vehicle, or as a power supply for a residence. In another
example, the battery system may be used to provide back-up power
for one or more devices in data center.
[0014] The battery system 100 of FIG. 1 includes a controller 102
electrically connected to one of the one or more power units
104-108. In one embodiment, the controller 102 may be included as
part of the battery system 100 for interfacing with the device or
devices to be powered by the battery system or to otherwise receive
or deliver electrical energy from the battery. In another
embodiment, the controller 102 is integrated into the powered
device or some other external component. For example, the
controller 102 may be a main controller of a hybrid car such that
the power units 102-108 may be connected to the existing controller
102 upon installation of the battery in the hybrid car, and the
battery provides motive energy to the electric motor on demand and
receives energy during regenerative braking and charging. The
battery may also receive or deliver energy in vehicle-to-grid
applications or other similar applications.
[0015] Regardless of whether the controller 102 is included as part
of the battery or connected to the controller upon installation in
the powered device, the controller may provide the general
instructions and control signals for managing the various modules
and components of the battery system. Further, the controller 102
may also receive signals from the components of the battery system
for utilization during operation of the battery system, such as
information about the performance of the modules or components of
the battery system. For example, the controller 102 may provide
signals to the one or more power units 104-108 to power-down or
power-up in response to a need with the powered device. The
controller 102 may also receive information about the power units
104-108, such as state of charge, voltage and/or current of each
unit, the temperature of each unit and verification of proper
operation of the modules and cells associated with the power units.
In another example, the controller 102 may provide request signals
to the power units 104-108 for balancing of the power units, as
explained in more detail below. The controller 102 or other
components of the BMS 100 may also store historical battery
information. A more detailed description of the components of the
controller 102 and the communication between the controller and the
power units 104-108 is provided below.
[0016] As mentioned, the controller 102 may be in electrical
communication with one of the one or more power units 104-108. As
shown in FIG. 1, the controller 102 is connected to a first power
unit of a plurality of serially connected power units, designated
in FIG. 1 as power unit 1 (104). More particularly, the controller
102 is electrically connected to a battery management system (BMS)
sub-controller 110 of the first power unit 104. As explained in
more detail below with reference to FIG. 2, the controller 102 may
be connected to the BMS sub-controller 110 of the first power unit
104 through any known means for wired communications, such as over
metal wires or optical fibers. In general, the connection between
the controller 102 and the power units 104-108 of the battery
system need only be sufficient to transmit control signals to and
from the control unit. Further, in some embodiments, the controller
may connect to BMS sub-controller 1 (110) to provide power signals
to power unit 1 (104). In one specific implementation,
communication and power occurs over a wiring harness of four wires
between units. The components of the BMS sub-controller are
discussed in more detail below with reference to FIG. 5.
[0017] As also shown in FIG. 1, the power unit 104 may include a
BMS sub-controller 110 electrically connected to one or more
battery modules 112-116. In one embodiment, the battery modules
112-116 are connected in series to the BMS sub-controller 110.
Thus, in power unit 1 (104), battery module 1 (112) is connected to
the BMS sub-controller 1 110, battery module 2 (114) is connected
to battery module 1 (112) and so on to battery module X (116),
designated as such to illustrate that any number of battery modules
may be connected in the serial connection. In this manner, each
power unit 104-108 may include any number of battery modules as
needed to provide the desired voltage and power for the particular
power unit. Further still, each battery module within each power
unit 104-108 may include any number of cells. For example, battery
modules 1 (112)-X (116) of power unit 1 (104) may each include six
battery cells (not shown), although other cell numbers are
possible. Thus, although shown in FIG. 1 as a single module, each
module of the battery system may include any number of batteries or
cells.
[0018] In addition, the cells of any battery module of the battery
system may be of varying chemistry makeup such that the battery
system 100 may include a variety of different types of batteries.
For example, module 1 (112) of power unit 1 (104) may include a
first chemical type of battery while module 1 (114) of power unit 2
(106) may include a second chemical type of battery. For example,
the cells may include any combination of lithium ion, sodium
sulfur, lithium-sulfur, nickel-cadmium, nickel metal hydride, lead
acid and any other conventional or to be developed cell type. Thus,
through this modular nature of the power units, each power unit
104-108 of the battery system 100 may include any type of battery
chemistry that provides the desired amount of voltage and power for
that particular power unit.
[0019] In other embodiments of the power unit 104, the battery
modules 112-116 may be connected in other configurations beside
serially. For example, the modules 112-116 may be connected in a
parallel connection. In another example, several battery modules
may be connected in serial, which are then connected in parallel
with other serially connected modules. In general, the battery
modules 112-116 of any power unit 104-108 may be connected in any
manner to provide the power unit with the desired voltage, power,
current charge or discharge capacity and/or storage capacity, or
other characteristics.
[0020] As mentioned above, the battery system 100 may include a
plurality of power units 104-106 connected serially to the
controller 102. As shown in FIG. 1, a second power unit, power unit
2 (106), is connected to the first power unit 104 in a similar
manner to the connection between the controller 102 and the first
power unit 104. More particularly, the BMS sub-controller 118 of
power unit 2 (106) is in electrical communication with the BMS
sub-controller 110 of power unit 1 (104). Similar to that of power
unit 1 (104), the BMS sub-controller 118 of power unit 2 (106)
connects to power unit 1 in such a manner as to receive control
signals and other communications from power unit 1 and to provide
status and other information about power unit 2 to power unit 1.
This communication may occur through any known means for
communicating electrically, including wired or optical fibers. A
power connection may also be present between power unit 1 (104) and
power unit 2 (106). In general, the connection between power unit 1
(104) and power unit 2 (106) of the battery system need only be
sufficient to transmit some control signals between the power
units. In one particular arrangement, the controller 102 and BMS
sub-controllers 110, 118, 126 are connected in a serial daisy
chain.
[0021] In this manner, any number of power units 104-108 may be
connected in the battery system 100. This is illustrated in FIG. 1
as the connection of power unit X (108) in the serial chain of the
connected power units. Power unit X (108) represents the last power
unit in the serial chain of power units of the any number of
connected units. Thus, the battery system 100 shown in FIG. 1 is
expandable or customizable to include any number of such units as
needed for the system. Also, although depicted as similar in
construction to power unit 1 (104), the power units 106-108 of the
battery system 100 may be constructed in different configurations
as the other power units. For example, power unit 2 (106) may
include fewer or more battery modules 120-124 than power unit 1
(104). Also, the battery modules 120-124 of power unit 2 (106) may
include a different number and type of cells. Further still, the
battery modules 120-124 of power unit 2 (106) may be connected in a
different manner than those of the other power units 104, 108 of
the battery system 100, such as in a parallel manner. Thus, through
the use of the battery management system discussed herein, the
battery system 100 is customizable in the number of power units
104-108 included in the system, as well as the number of battery
modules, battery types included in each battery module and the
configuration of battery modules for each power unit.
[0022] In one aspect, the BMS provides for the removal,
replacement, addition and/or exchange of power units with minimal
disruption to the system overall. For example, if power unit 2
(106) of the battery system 100 fails or falls below some
performance criteria, the power unit may be removed and replaced
with a replacement unit that operates properly and within
specifications without the need to customize or reprogram the
controller 102. Further, as explained in more detail below, it is
not required that the added or replacement units 104-108 have the
same structure or characteristics of the other power units. Rather,
the power units 104-108 may be added or exchanged in near real time
once the new units are connected in the communication chain of the
battery system 100. The integration of the power units 104-108 in
the communication chain of the system 100 is described in more
detail below. The capability to insert or replace power units
104-108 within the battery system 100 is markedly different from
previous battery systems.
[0023] FIG. 2 is a block diagram illustrating a portion of the
communication and power links between the BMS sub-controllers and
controller of the battery management system of FIG. 1. Thus, the
controller 202 and BMS sub-controllers 210-226 of FIG. 2 are
similar to the related components shown in FIG. 1 as discussed
above. It should be noted that similar components are numbered
similarly between the Figures. For example, the controller has a
notation of 102 in FIGS. 1 and 202 in FIG. 2 to indicate that these
components are similar. In addition, although not shown in FIG. 2,
the BMS sub-controllers 210-226 of FIG. 2 may be connected to and
transmit and receive information from one or more battery modules
connected to the sub-controllers, as shown in FIG. 1.
[0024] As shown in FIG. 2, the controller 202 may transmit control
or other signals to the BMS sub-controllers 210-226 to control the
BMS sub-controllers and the associated battery modules. Although
the term "control signal" is used herein, the term should be
construed to include any type of signal that includes information
between the components of the battery system, such as instructions
to be executed or information about the operation of the various
components of the system. In general, the control signals from the
controller 202 propagate through the serial connection of the BMS
sub-controllers 210-226 on a communication link referred to herein
as the "downstream link". More particularly, the controller 202 may
provide the control signal on the downstream link 240 between the
controller 202 and BMS 1 (210), or the first BMS sub-controller in
the serial connection. The BMS sub-controller 1 210, upon receipt
of the control signal from the controller 202, may respond to the
control signal by transmitting a response to the controller on an
upstream link 250 between the controller and BMS 1. In addition to
the response or in the alternative, BMS 1 (210) may transmit the
control signal on the downstream link 242 between BMS 1 and BMS
sub-controller 2 218. In some embodiments, however, BMS 1 (210) may
interpret the control signal as being associated with BMS 1 only
and will not transmit the control signal to BMS 2 (218). For
example, the control signal may include a header or other portion
that includes an address for a particular BMS of the system such
that, when received by the particular BMS, is recognized as being
associated with the particular BMS only. In other embodiments, BMS
1 (210) may generate a new control signal in response to the
control signal received by the controller 202 and transmit the
newly generated control signal on downstream link 242 to BMS 2
(218). The general formatting of the control signals transmitted on
the upstream and downstream links is discussed in more detail below
with reference to FIG. 3.
[0025] In response to receiving the control signal from BMS 1
(210), BMS 2 (218) may respond in a similar manner by transmitting
a response signal on upstream link 248 to BMS 1, which in turn may
respond to the response signal provided by BMS 2 and/or transmit
the signal to the controller 202 on upstream link 250. In another
example, BMS 1 (210) may, in response to the signal received by BMS
2 (218), generate a control signal to transmit to BMS 2 on
downstream link 242 or to the controller 202 on upstream link 250.
In general and as discussed in more detail below with reference to
FIG. 3, the BMS sub-controllers 210-226 may respond to any received
control signal, whether received upstream or downstream, by
transmitting the control signal on any available communication
link, configuring the BMS in some manner in response to the control
signal, by generating a subsequent control signal and/or
transmitting the subsequent control signal on any available
communication link. In addition, the BMS sub-controllers 210-226
may also generate and transmit a control signal at any time in
response to states internal to the BMS sub-controller or associated
battery modules.
[0026] This process of receiving and transmitting the control
signals to/from the controller 202 and BMS sub-controllers 210-218
may continue along the serial connection of BMS sub-controllers to
BMS sub-controller X (226), which represents the last BMS
sub-controller in the serial chain of any number of BMS
sub-controllers. BMS sub-controller X (226) communicates with the
rest of the BMS sub-controller chain on downstream link 244 and
upstream link 246 in a similar manner as described above.
[0027] The communication links between the controller and the BMS
sub-controllers, as well as between the BMS sub-controllers may be
any type of electrical communication known or hereafter developed
to communicate signals through a physical medium between electrical
devices. Thus, the communication between the components may occur
over wires or optical cabling. In addition, the communication may
occur based on a common clock signal to the components or may occur
asynchronously.
[0028] In addition to the communication links, the controller 202
may also provide a power enable signal and/or electrical power to
the BMS chain on power link 252. As described in more detail below,
the power enable signal provided by the controller 202 aids the
battery system in saving power and operating needs. Further, in a
manner similar to the control signals being propagated along the
serial chain of BMS sub-controllers 210-226, the power enable
signal may also be propagated from sub-controller to sub-controller
along power links between the sub-controllers, illustrated in FIG.
2 as power link 254 between BMS 1 (210) and BMS 2 (218) and power
link 256 between BMS 2 and BMS X (226).
[0029] As mentioned above, each of the one or more BMS
sub-controllers may provide and receive information and/or
instructions associated with the battery system. For example, the
BMS sub-controller for any one power unit may acquire the voltages
and/or temperature of the battery modules associated with the BMS
sub-controller. This information may then be provided to the
controller or other BMS sub-controllers. In another example, the
controller may provide an instruction to the BMS sub-controllers of
the battery system to perform load balancing among the battery
modules.
[0030] FIG. 3 is diagram illustrating an exemplary communication
flow between the components of the battery management system of
FIG. 1. The communication flow illustrated is but one example of
the process by which the controller and BMS sub-controllers may
communicate and is provide here to further illustrate the
communication possibilities of the battery management system
disclosed. However, the battery management system may employ any
known or hereafter developed communication protocol to share
information and instructions between the controller and the one or
more BMS sub-controllers. Additionally, the communication example
of FIG. 3 is described below in relation to the battery management
configuration similar to those shown in FIG. 1 and FIG. 2. In
particular, the communication protocol example is shown for a
battery system including a controller and three BMS sub-controllers
connected in a serial chain. It should be appreciated, however,
that other configurations, such as configurations with more than
three BMS sub-controllers or sub-controllers connected in a
non-serial manner, may result in a different communication protocol
than that provided in example of FIG. 3.
[0031] In the example communication provided in FIG. 3, a message
is generated by the controller 202 that requests information from
each of the three BMS sub-controllers associated with the
controller. This is designated in the graph as box "MSG 1" in the
lower left corner of the graph. More particularly, as the MSG 1 box
is included above the controller notation 301 indicating that the
controller generates or receives MSG 1. Additionally, the x-axis of
the graph indicates that MSG 1 begins this particular communication
at time 0. It should be appreciated that the time values provided
in FIG. 3 are merely place holders to indicate a later time and do
not correlate to actual time values, which may depend on any number
of factors, including processing time of the controller and BMS
sub-controllers, transmission speeds of the upstream and downstream
links and the presence or absence of a system control clock.
Further, although in this example MSG 1 is a command or instruction
generated by the controller 202 that requests information from the
BMS sub-controllers 210-226, the message may be any communication
or instruction to the BMS sub-controllers. For example, MSG 1 may
be an initialization command to initialize the BMS sub-controllers
with the controller. This initialization command is explained in
more detail below. In another example, MSG 1 may instruct the BMS
sub-controllers 210-226 to begin a load balancing routine to
balance the battery system. In addition, the message may originate
from some other component within the system or separate from the
system besides the controller.
[0032] At time 1, the controller 202 transmits MSG 1 to BMS 1 (210)
over downstream link 240. This is indicated in FIG. 3 as
transmission 302 as MSG 1 appears in BMS 1 column 303. As indicated
above, MSG 1 may instruct BMS 1 to return information, such as
voltage or temperature readings of the battery modules associated
with the BMS sub-controller, back to the controller 202. This
information may be gathered and stored by BMS 1 (210) during normal
operation of the sub-controller and related power unit. Thus, in
response to MSG 1, BMS 1 (210) transmits the stored information,
shown as box RSP 1 at time 2, to the controller 202 on upstream
link 250 (shown in graph as transmission 304). Also, BMS 1 (210)
may also retransmit MSG 1 to the next BMS sub-controller in the
serial chain. For example, BMS 1 (210) transmits MSG 1 to BMS 2
(218) over downstream link 242 (shown in graph as transmission
306).
[0033] In response to receiving the requested information (RSP 1)
from BMS 1 (210), the controller 202 may then generate a "NEXT"
command at time 3 and transmit 308 the NEXT command to BMS 1 (210)
over downstream link 240 to propagate the NEXT command along the
serial chain. In general, the "NEXT" command instructs the BMS
sub-controller that receives the command to transmit upstream any
information being held by the sub-controller. For example, BMS 2
(218), in response to receiving MSG 1 transmits at time 3 the
requested information, shown as box RSP 2, along upstream link 248
to BMS 1 (transmission 310). Upon receipt of this information, BMS
1 (210) may store RSP 2 until a command from the controller 202 is
received on how to process the information. This command is the
NEXT command transmitted 308 at time 3 by the controller 202 and
received at time 4. Thus, upon receipt of the NEXT command, BMS 1
(210) transmits, at time 5, RSP 2 to controller 202 on upstream
link 250, as shown in transmission 312. In this manner, the BMS
sub-controllers may store any response or information received on
the upstream link until a command (such as the NEXT command) is
provided by the controller to continue propagating the response
upstream to the next BMS sub-controller in the serial chain.
[0034] As illustrated, the NEXT command allows for the upstream
propagation of information through the daisy chain configuration of
the battery system to the controller. However, in some embodiments
of the battery system, the controller 202 may be connected directly
to each BMS sub-controller 210-226 such that the information
provided by the sub-controllers may be transmitted directly to the
controller. In this configuration, the NEXT command may be omitted
as the information is sent directly to the controller. However,
connecting the sub-controllers 210-226 to the controller 202
serially greatly reduces the physical wiring needed for
communication between the controller and the power units.
[0035] Returning to time 2, BMS 2 (218) may, in addition to
providing RSP 2 to BMS 1, transmit MSG 1 on the downstream link 244
to BMS 3 (transmission 314). In this manner, MSG 1 is propagated to
each BMS sub-controller in the serial chain. In response to MSG 1,
BMS 3 306 transmits the sub-controller information (RSP 3) on the
upstream link 246 to BMS 2 (218) at time 4 (transmission 316). Also
at time 4, BMS 1 (210) transmits the NEXT command to BMS 2 (218)
over the downstream link 242 (transmission 318). As BMS 2 (218) is
storing RSP 3 when the NEXT command is received, BMS 2 transmits
RSP 3 over upstream link 248 to BMS 1 (transmission 320). BMS 2
(218) may also transmit the NEXT command to BMS 3 306 (transmission
322). However, because BMS 3 is the final BMS in the serial chain,
BMS 3 is not storing any information from a down chain BMS and
ignores the NEXT command.
[0036] Also at time 6, the controller 202 generates a second NEXT
command in response to receiving RSP 2, or the information from BMS
2. The second NEXT command is then transmitted (324) to BMS 1 (210)
in a similar manner as described above. Further, because BMS 1
(210) is storing RSP 3 (received at time 6), BMS 1 responds to the
received NEXT command by transmitting (326) RSP 3 upstream to the
controller. Also, the second NEXT command may be propagated through
the serial chain through transmissions 328 and 330. However,
because BMS 2 and BMS 3 do not store any additional information
from downstream BMS sub-controllers, the NEXT command may be
ignored by BMS 2 and BMS 3. As shown by the communication protocol
outlined above and in FIG. 3, the controller 202 generates a
message to retrieve information from the BMS sub-controllers of the
battery system and receives response 1 through 3 that contain the
information. In response to receiving the requested information,
the controller 202 may then generate a second message, such as MSG
2 shown at time 9, which is then communicated to the BMS
sub-controllers in a similar manner as described.
[0037] It should be noted that the transmission protocols described
herein do not need to occur at regular timed intervals, but may
also be asynchronous. Thus, the time indications included in FIG. 3
may indicate occurrences at a later time triggered by a received
command or instruction. In other embodiments, the transmission of
the signals may be governed by a clock signal common to the
components of the battery system.
[0038] Another example of an instruction transmitted by the
controller 202 in the manner described above is an initialization
command (INIT) that may be used to address the BMS sub-controllers
of the battery system. In general, the INIT command provides each
BMS sub-controller in the battery system an address or ID number
that corresponds to the sub-controller's relative placement in the
serial chain of power units. Similar to the communication described
above, the INIT command may be provided by a controller and an
acknowledgment message may be provide back to the controller from
the BMS sub-controllers.
[0039] In particular, the controller 202 of the battery system may
transmit the INIT command downstream to BMS 1 (210). The INIT
command includes an indication of the ID number of the first BMS
that receives the INIT command, typically a value of "1". Upon
receipt, BMS 1 (210) will set an internal address register to the
value contained in the INIT command and transmit an acknowledgement
(ACK) message back to the controller 202 on the upstream link. In
addition, BMS 1 (210) generates an INIT command that includes an ID
number one greater than the stored ID number, in this case a value
of "2". Once generated, the newly generated INIT command is
transmitted to BMS 2 (218) on the downstream link.
[0040] BMS 2 (218) processes the INIT command in a similar manner
as BMS 1 (210) described above. Thus, BMS 2 (218) sets an internal
address register to the value contained in the INIT command ("2")
and transmits an acknowledgement (ACK) message on the upstream link
to BMS 1 202. In addition, BMS 2 (218) generates a INIT command
that includes an ID number one greater than the stored ID number,
in this case a value of "3", and transmits the newly generated INIT
command on the downstream link to the next BMS sub-controller in
the serial chain. This action continues until each BMS
sub-controller has received an INIT command and has an associated
address or ID number.
[0041] In some cases, the INIT command may not be properly executed
by the BMS sub-controller. For example, the INIT command may be
corrupted during transmission such that the BMS sub-controller
cannot recognize or verify an address or ID number. In another
example, the BMS sub-controller may be the final sub-controller in
the serial chain and, thus, cannot transmit a generated INIT
command to the next BMS. In these cases, the BMS sub-controller may
transmit a non-acknowledgment (NACK) signal on the upstream link to
indicate that a failure has occurred in the addressing or
initialization command.
[0042] Utilizing the NEXT commands as described above, the
controller 202 can propagate each ACK or NACK responses upstream
through the serial chain back to the controller. In general, the
controller 202 continues to generate NEXT commands until a NACK
message is received, indicating that each BMS sub-controller has
been properly addressed within the serial chain. Thus, through the
INIT command, the controller 202 can address each power unit
connected in the battery system, regardless of the configuration of
the power units within the system. By addressing the
sub-controllers, the controller 202 may transmit messages directly
to one or more sub-controllers of the system by including the
address for the particular sub-controller in a header or other
portion the message.
[0043] The functionality of the battery management system to
initialize or address the connected power units associated with the
controller provides flexibility in designing and configuring a
battery system. For example, the battery management system
described herein may be incorporated or utilized for different
configurations and types of battery systems. Thus, a computing
device using a 300 volt battery pack may utilize the battery
management system in a similar manner as a computing device using a
240 volt battery pack, without the need to design a customized
control system for the different computing devices. Rather, the
proper power units for the computing device may be connected to the
controller and, through the initialization and addressing operation
described above, the controller may begin communicating with the
power units, without the need for designing a customized controller
and/or sub-controllers. In this manner, the battery management
system described herein may be incorporated into varying battery
pack configurations as needed by the powered computing device
without minimal customizing to the components, providing a modular
solution for battery pack management.
[0044] In addition, the battery management system described herein
allows for any number of power units and battery management
sub-controllers to be associated with the controller without the
need for programming or configuring the controller as to the number
of units connected. Rather, any number of power units may be
connected serially in the battery system and the controller,
through the initialization process described above, provides an
address or ID number to the units without any prior knowledge of
the number of units connected. Further, the initialization process
informs the controller to the number of power units connected to
the controller for future use by the controller in providing
commands and information requests.
[0045] In addition, the battery system allows for the battery pack
configuration to be altered with minimal configuring of the system.
For example, a user of the battery system may remove power units or
add power units to the battery system that may be recognized
automatically by the system. For example, once the controller
detects that a power unit has been removed or added (generally
through receiving a command from an un-addressed unit or receiving
a NACK response), the controller may begin the initialization
process to remap the power units connected in the battery system.
Depending on the transmission and processing speed of the system,
this initialization process may be conducted in less than a second,
allowing for the alteration to the configuration of the battery
system quickly. In response, the controller may adjust the
configuration of the entire battery system to account for the added
or removed power unit (such as requesting more voltage from the
remaining power units or distributing the requested power between
the communicating power units) to provide the expected voltage from
the battery system to the computing device.
[0046] In one embodiment, the battery management system may perform
this initialization sequence at set intervals to ensure that the
current battery system configuration is detected. In yet another
example, the initialization process allows for the replacement of
one or more power units without the need to address the units
within the battery system as the controller, through the
initialization process, provides the address to the unit or units
regardless of where in the serial chain the replaced units are
placed. In this manner, the initialization sequence of the battery
systems described herein provides flexibility in the alteration and
configuration of the battery system.
[0047] Once initialized, the controller may request information
from the power units of the battery system for operation, charge,
discharge and maintenance of the system. For example, each BMS
sub-controller may store information concerning the battery modules
associated with the sub-controller, such as the number of battery
modules supported, voltage limits, estimated state of charge,
module state of health, etc. This information may be requested from
each BMS sub-controller by the controller for use in operation of
the battery system. Further, as explained above, each power unit
may include any number and kind of battery modules such that the
power units may be of different configurations. Information for
each power unit may be stored by the controller and used during
operation of the battery system, such as for determining error
conditions and/or operating parameters of the battery system.
[0048] In addition, the connection of the BMS sub-controllers to
the controller to control the various power units of the battery
system may be independent of the battery connection configuration.
For example, some battery systems connect the power units in
parallel rather than a serial connection for various performance
considerations. However, it is not required that the BMS
sub-controllers as described herein also be connected in a parallel
manner. Rather, the controller and BMS sub-controllers may be
connected serially and operate as described above, regardless of
the configuration of the connection between the battery modules of
the system. While the controller may be programmed to account for
the parallel nature of the battery system, the communication links
between the controller and the BMS sub-controllers, as well as
between the BMS sub-controller themselves, may be done in a serial
configuration such that the performance and communication of the
controller and the BMS sub-controllers operates as described above.
Thus, the battery management system may be independent of the
battery pack structure.
[0049] Another advantage offered by the battery management system
described herein is the capability to actively control the power
supplied to each BMS sub-controller controller, to disable power to
the BMS sub-controllers when the system is in an idle state or a
fault state in response to a detected problem within the battery
system. Further, by electrically isolating each BMS sub-controller,
the sub-controllers are capable of communicating across large
potential differences of the power units of the battery system.
FIG. 4 and FIG. 5 show a simplified version of the components of
the controller and BMS sub-controllers to illustrate this control
of the power to the sub-controllers by the controller.
[0050] FIG. 4 is a block diagram illustrating a controller of a
battery management system for the battery systems described herein.
The controller 400 is similar to the controller shown in FIGS. 1
and 2 for communication with and control of a battery system. More
particularly, the controller 400 communicates with one or more BMS
sub-controllers of a battery system to control the battery modules
associated with the BMS sub-controllers, including receiving
information concerning the battery modules and for performing load
balancing of the battery modules.
[0051] The controller 400 of the battery system includes a
processor 402 or processing device connected to a storage device
404. The storage device 402, referred to as main memory 816, or a
random access memory (RAM) or other computer-readable devices
coupled to the processor 402 for storing information and
instructions to be executed by the processor. Common forms of
machine-readable medium may include, but is not limited to,
magnetic storage medium (e.g., floppy diskette); optical storage
medium (e.g., CD-ROM); magneto-optical storage medium; read only
memory (ROM); random access memory (RAM); erasable programmable
memory (e.g., EPROM and EEPROM); flash memory; or other types of
medium suitable for storing electronic instructions.
[0052] The storage device 402 also may be used for storing
temporary variables or other intermediate information during
execution of instructions by the processor 402. The controller may
also include a read only memory (ROM) (not shown) and/or other
static storage device coupled to the processor 402 for storing
static information and instructions for the processor. The
controller set forth in FIG. 4 is but one possible example of a
controller that may employ or be configured in accordance with
aspects of the present disclosure.
[0053] According to one embodiment, the processor 402 may execute
one or more sequences of one or more instructions contained in the
storage device 404. These instructions may be read into the storage
device 404 from another machine-readable medium. Execution of the
sequences of instructions contained in storage device 404 may cause
processor 402 to perform one or more of the process steps described
herein. In alternative embodiments, circuitry may be used in place
of or in combination with the software instructions. Thus,
embodiments of the present disclosure may include both hardware and
software components.
[0054] As shown in both FIG. 4 and FIG. 2, the controller 400 may
include a downstream link 440 for transmitting signals to other
components of the battery system. Similarly, the controller 400 may
include an upstream link 450 for receiving signals and other
information from the battery system. The downstream link 440 and
upstream link 450 may each be connected to a buffer 416 connected
between the links and the processor 402 of the controller. These
links provide the transmission media on which the control signals
described above may be sent to the BMS sub-controllers of the
battery system. As described, in some embodiments, the links may be
wires or optical cabling communication links.
[0055] In addition, the controller may include a power supply 406
for providing power to the BMS sub-controllers of the battery
system. More particularly, the power supply 406 may provide a power
connection 452 and a common or ground connection to the BMS
sub-controller connected to the controller. In one embodiment, the
power for each BMS sub-controller connected to the controller 400
may be provided by the controller power supply 406. However, in
other embodiments and explained in more detail below, the power for
each BMS sub-controller is provided by the one or more battery
modules associated with the sub-controller. In these embodiments,
the power signal 452 provided by the controller 406 is a "power
enable" signal that signals the BMS sub-controller to power the
sub-controller from the associated battery modules. Thus, a high
signal on the power line 452 enables power to the sub-controller,
while a low signal on the power line removes power from the BMS
sub-controller.
[0056] To control the power line 452, an enable switch 408 may be
connected to the processor 402 of the controller 400. The enable
switch 408 may be a physical switch, an electrical circuit
equivalent or an instruction provided by the processor for enabling
the power line 452. In general, the enable switch 408 is configured
to receive a signal from the processor 402 that allows the signal
on the power line 452 or disconnects the power line from the power
supply 406.
[0057] FIG. 5 is a block diagram illustrating a BMS sub-controller
for a battery system described herein, including electrical
isolation on inputs to the sub-controller. In general, the BMS
sub-controller 500 is similar to the BMS sub-controllers shown in
FIGS. 1 and 2. Further, the BMS sub-controller 500 includes a
processor 502 and storage device 504 in a similar configuration of
the controller described above. Also similar to the controller
described above, the BMS sub-controller 500 may include a
downstream output link 542 for transmitting signals to other BMS
sub-controllers of the battery system and an upstream input link
548 for receiving signals and other information from the other BMS
sub-controllers. The downstream output link 542 and upstream input
link 548 may each be connected to a buffer 516 connected between
the links and the processor 502 of the controller. These links
provide the transmission media on which the control signals
described above may be transmitted to the BMS sub-controllers of
the battery system. As described, in some embodiments, the links
may be wires or optical cabling communication links.
[0058] As also shown, the BMS sub-controller 500 may receive a
downstream input link 540 from either the controller or another BMS
sub-controller for receiving control signals. In one embodiment,
the downstream input link 540 may be connected to an electrical
isolator 520, such as an opto-isolator designed to transfer
electrical signals by utilizing light waves. In general, the
electrical isolator 520 may be any known or hereafter developed
isolating device for electrically isolating the power units.
Similarly, the BMS sub-controller 500 may also include an upstream
output link 550 from either the controller or another BMS
sub-controller for transmitting control signals. In one embodiment,
the upstream output link 550 may be connected to an electrical
isolator 522 for isolating the upstream link from a connected BMS
sub-controller or controller. These upstream and downstream links
may be utilized by the BMS sub-controller to transmit and receive
control signals as described above.
[0059] In addition, the BMS sub-controller 500 may include a power
supply enable device 506 for enabling power to the BMS
sub-controller. More particularly, the power supply enable device
506 may receive an enable signal on a power enable input 552. For
example, the power enable input 552 may be connected to a
controller of the battery system. The controller, similar to that
described above with reference to FIG. 4, may provide a signal on
the power enable input 552 line to enable power to the BMS
sub-controller 500. When the enable signal is received, the power
supply enable device 506 may begin supplying power to the BMS
sub-controller 500, such as from the battery modules associated
with the BMS sub-controller 500. In addition, the power enable
input 552 may be connected to a electrical isolating device 524 to
electrically isolate the BMS sub-controller 500 from the device
supplying the power enable signal.
[0060] Further, the power supply enable device 506 of the BMS
sub-controller 500 may also provide or retransmit the received
power enable signal. More particularly, a power enable signal
output 554 and common output 556 may be connected to the power
supply enable device 506. The power supply enable device 506 may be
configured to transmit a power enable signal on the enable signal
output 554 under certain conditions. For example, the power supply
enable device 506 may provide the enable signal on the power output
554 when the enable signal is received at the power enable input
552. In another example, the processor may control the power supply
enable device 506 to provide the enable signal when a command from
the controller is received or when certain conditions of the power
unit are achieved.
[0061] As shown in FIG. 2, the BMS sub-controllers may be connected
in a serial connection. Thus, turning to FIG. 5, the downstream
output link 542 of the BMS sub-controller shown may be connected to
a downstream input link of a similar BMS sub-controller and the
input upstream link 548 may be connected to an upstream output link
of the similar BMS. In this manner, the BMS sub-controllers may
propagate signals or otherwise communicate on the upstream and
downstream links. Further, the power output 554 may be connected to
the power input of the similar BMS sub-controller for control of
the power to the similar BMS sub-controller. Also, by utilizing the
isolation devices 52-524, the BMS sub-controllers may be
electrically isolated from each other to prevent damage to any one
sub-controller should a failure occur at a connected
sub-controller.
[0062] Utilizing the above described configurations and techniques
for the battery system, the controller may also transmit one or
more commands to the BMS sub-controllers to balance the cells
and/or modules of the battery to protect the battery system and
achieve greater performance. For example, battery systems composed
of one or many cells may only supply enough current as the weakest
module. In addition, battery systems may be damaged or become
dangerous when the battery cells are over-discharged or
over-charged passed the specifications of the battery cells.
Further, a full charge and discharge of the battery cells provide a
longer battery cell life cycle. To address this, the battery
management systems described herein may balance the battery modules
so they remain as close to equal as possible to provide the best
performance.
[0063] To perform the cell balancing, the battery system may
utilize the structures and methods described above. For example,
returning to FIG. 1, the controller 102 may begin a cell balancing
routine to balance the cells/modules of the battery system. The
controller 102 may provide an instruction to the power units
104-108 connected to the controller instructing the power units to
perform the balancing routine. More particularly, the controller
102 may transmit the instruction to BMS 1 110 of the first power
unit in a similar manner as described above with reference to FIG.
3. In turn, BMS 1 110 may transmit or propagate the balancing
instruction to BMS 2 118, and so forth down the serial connection
of power units. An acknowledgement message may be transmitted from
each BMS sub-controller back to the controller 102 to acknowledge
receipt of the balancing command. In addition, the balancing
command may include the target state of charge for each module or
cell within the battery system. Upon receipt of the balancing
command, the BMS sub-controllers may perform the balancing routine
as described above for the modules and cells associated with that
sub-controller by activating energy dissipating devices for those
cells above the target state of charge. For example, the BMS
sub-controller may provide a signal to close a switch to connect a
resistor across the cell for a particular amount of time to remove
energy from the cell.
[0064] In another embodiment, the controller 102 may request
performance information from each BMS sub-controller connected to
the controller. This information may contain performance statistics
for the modules or cells associated with the BMS sub-controllers.
Based on this information, the controller 102 may then issue
balancing instructions specifically targeted toward a BMS
sub-controller or even a module or cell associated with a BMS
sub-controller of the battery system. The BMS sub-controller may
perform the requested balancing by activating an energy dissipating
device for the cell or module in question. In this manner, the
controller 102 may control the balancing operation to balance the
output of the connected batteries.
[0065] Although the present disclosure has been described with
respect to particular apparatuses, configurations, components,
systems and methods of operation, it will be appreciated by those
of ordinary skill in the art upon reading this disclosure that
certain changes or modifications to the embodiments and/or their
operations, as described herein, may be made without departing from
the spirit or scope of the disclosure. Accordingly, the proper
scope of the disclosure is defined by the appended claims. The
various embodiments, operations, components and configurations
disclosed herein are generally exemplary rather than limiting in
scope.
* * * * *