Parallel and / or series hybrid pack modes in battery management system

Abstract

Embodiments included herein are directed towards a method and a system for a battery management system (BMS). Embodiments of the present disclosure may include connecting multiple BMSs running on a software in at least one of pack mode configurations using a primary isolated controller area network (CAN) interface and a secondary isolated CAN interface of at least one BMS. The pack mode configurations may include one or more of : a parallel pack mode, a series pack mode, and a parallel / series hybrid pack mode. Embodiments may further include automatically identifying and configuring each BMS of the multiple BMSs either as a follower BMS or a leader BMS. Embodiments may also include aggregating battery measurement data associated with either the follower BMS or the leader BMS to calculate unified data to be exchanged with an external controller.

Description

Parallel and / or Series Hybrid Pack Modes in Batery Management SystemCross-Reference to Related Applications

[0001] The present application claims the benefit of U.S. Provisional Patent Application No. 63 / 626,610, entitled “Parallel and / or Series Hybrid Pack Modes in Battery Management System,” filed on 30 January 2024. The entire disclosure of which is incorporated herein by reference.Technical Field

[0002] The present disclosure generally applies to battery management systems, more specifically a system and method for a battery management system in battery power applications.Background

[0003] A battery management system (BMS) is an essential component in battery power applications, for example, electric vehicles powered by high voltage battery systems which may include multiple cells. It may protect batteries from an unsafe operation and calculate the battery status. Generally, one BMS is required in a single application, such as a battery pack may be required in an electric vehicle, or a compact energy storage system. Many applications may use a battery system with voltage limited to 60 V as higher voltage limit may require more regulation and safety measurements. Customers may use currently developed BMS products to build a modular battery pack which may fit into many battery powered applications. However, due to an increasing demand on higher power output and larger capacity, it is desirable to connect multiple battery modules in parallel to increase capacity or in series to increase voltage level.

[0004] Conventional BMS may be designed as a standalone system which may exchange information with other controllers in a battery powered applications (e.g.,electric vehicles or energy storage system). As the voltage level varies between applications, it may be difficult to develop one BMS to fit all requirements due to the cost and complexity. Customers may prefer some flexibility to connect multiple battery packs to achieve either higher voltage or higher capacity. Once a battery system is designed and built, it is not easy to expend it to achieve higher power rating or large capacity.

[0005] The existing BMS product may support limited capability in parallelization but may not support series connection. One alternative is to use a high voltage BMS product to monitor the increased number of battery cells, but the resulting cost may be much higher. Additionally, the high voltage BMS may require more space to install which may be difficult for a compact battery system.Summary of the Disclosure

[0006] As will be discussed in greater detail below, embodiments included herein are directed towards a battery management system (BMS).

[0007] In one or more embodiments of the present disclosure, a method for the BMS is included. The method may include connecting multiple BMSs running on a software in at least one of pack mode configurations using a primary communication interface and a secondary communication interface of at least one BMS. The pack mode configurations may include one or more of: a parallel pack mode, a series pack mode, and a parallel / series hybrid pack mode. The method may also include automatically identifying and configuring each BMS of the multiple BMSs either as a follower BMS or a leader BMS. The method may also include aggregating battery measurement data associated with either the follower BMS or the leader BMS to calculate unified data to be exchanged with an external controller.

[0008] One or more of the following features may be included. In some embodiments, if primary communication interfaces of the multiple BMSs are connected together, the software of the multiple BMSs may switch to the parallel pack mode. If the primary communication interface of the at least one BMS is connected to asecondary communication interface of another BMS, the software of the multiple BMSs may switch to the series pack mode. If a first series pack mode, a second series pack mode, and a third series pack mode are connected in the parallel pack mode by connecting the primary communication interfaces of each top BMS of the multiple BMSs, the software of the multiple BMSs switches to the parallel / series hybrid pack mode. One or more features of the software such as a contactor control and a current measurement may be disabled while the software of the multiple BMSs switches to the series pack mode. In either the parallel pack mode or the series pack mode, each BMS may share battery measurement data with other BMS and the leader BMS may be automatically assigned to calculate the unified data to be exchanged with the external controller. In the series pack mode, the leader BMS may be assigned to a top BMS of the multiple BMSs and data from each follower BMS may be aggregated to calculate the unified data. An operation of the multiple BMSs in the parallel / series hybrid pack mode is same as a single BMS.

[0009] In one or more embodiments of the present disclosure, a BMS is provided. The BMS may include a primary communication interface. The BMS may further include a secondary communication interface. The BMS is used with a battery pack comprising a plurality of battery modules and each of the plurality of battery modules comprising a plurality of cells. The BMS may further include a cell monitoring unit configured to measure battery characteristic data of the battery modules. The cell monitoring unit is connected with at least one of the plurality of battery modules. The cell monitoring unit is configured to encode the battery characteristic data and transmit the battery characteristic data to an external controller.

[0010] One or more of the following features may be included. In some embodiments, each BMS of the multiple BMSs may automatically identify and configure either as a follower BMS or a leader BMS. The multiple BMSs running on a software may be connected in at least one of pack mode configurations using the primary communication interface and the secondary communication interface of at leastone BMS. The pack mode configurations may include one or more of: a parallel pack mode, a series pack mode, and a parallel / series hybrid pack mode. If primary communication interfaces of multiple BMSs may be connected together, a software of the multiple BMSs may switch to the parallel pack mode. If the primary communication interface of at least one BMS may be connected to a secondary communication interface of another BMS, the software of the multiple BMSs may switch to the series pack mode. If a first series pack mode, a second series pack mode, and a third series pack mode are connected in the parallel pack mode by connecting the primary communication interfaces of each top BMS of the multiple BMSs, the software of the multiple BMSs switches to the parallel / series hybrid pack mode. One or more features of the software such as a contactor control and a current measurement may be disabled while the software of the multiple BMSs switches to the series pack mode. In either the parallel pack mode or the series pack mode, each BMS shares battery measurement data with other BMS and the leader BMS may be automatically assigned to calculate unified data to be exchanged with the external controller. In the series pack mode, the leader BMS may be assigned to a top BMS of the multiple BMSs and data from each follower BMS may be aggregated to calculate the unified data. An operation of the multiple BMSs in the parallel / series hybrid pack mode is same as a single BMS.

[0011] The details of one or more example implementations are set forth in the accompanying drawings and the description below. Other possible example features and / or possible example advantages will become apparent from the description, the drawings, and the claims. Some implementations may not have those possible example features and / or possible example advantages, and such possible example features and / or possible example advantages may not necessarily be required of some implementations.

[0012] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended toidentify essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.Brief Description of the Drawings

[0013] The accompanying drawings, which are included to provide a further understanding of embodiments of the present disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and together with the description serve to explain the principles of embodiments of the present disclosure.

[0014] FIG. 1A sets forth a block diagram of a low voltage battery management system in accordance with embodiments of the present disclosure;

[0015] FIG. IB sets forth a block diagram of a high voltage battery management system in accordance with embodiments of the present disclosure;

[0016] FIG. 2 illustrates a schematic illustrating a single battery management system in accordance with embodiments of the present disclosure;

[0017] FIG. 3 illustrates a schematic illustrating a parallel pack mode in accordance with embodiments of the present disclosure;

[0018] FIG. 4 illustrates a schematic illustrating a series pack mode in accordance with embodiments of the present disclosure;

[0019] FIG. 5 illustrates a schematic illustrating a parallel / series hybrid pack mode in accordance with embodiments of the present disclosure;

[0020] FIG. 6 illustrates a flowchart in accordance with embodiments of the present disclosure;

[0021] Like reference symbols in the various drawings may indicate like elements.Detailed Description

[0022] The discussion below is directed to certain implementations. It is to be understood that the discussion below is only for the purpose of enabling a person withordinary skill in the art to make and use any subject matter defined now or later by the patent “claims” found in any issued patent herein.

[0023] It is specifically intended that the claimed combinations of features not be limited to the implementations and illustrations contained herein, but include modified forms of those implementations including portions of the implementations and combinations of elements of different implementations as come within the scope of the following claims. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementationspecific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. Nothing in this application is considered critical or essential to the claimed invention unless explicitly indicated as being "critical" or "essential."

[0024] It will also be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first object or step could be termed a second object or step, and, similarly, a second object or step could be termed a first object or step, without departing from the scope of the invention. The first object or step, and the second object or step, are both objects or steps, respectively, but they are not to be considered a same object or step.

[0025] Most battery monitoring system (“BMS”) may be designed to be operated as a standalone system. It is not possible to connect multiple BMSs in series and / or in parallel without software and hardware customization. In accordance with various embodiments of the present invention directed to a method and a system associated with the BMS, this problem may be resolved through a software implementation and asmall hardware upgrade, multiple compact BMSs may be connected in parallel, series, or parallel / series hybrid configuration by adding a secondary communication interface to the BMS as described in detail below. Each BMS of the multiple BMSs may run the same software.

[0026] In some embodiments, each BMS has two communication interfaces: a primary communication interface and a secondary communication interface of the BMS. In some embodiments, if primary communication interfaces of the multiple BMSs are connected together, the software may switch to a parallel pack mode. In some other embodiments, if the primary communication interface of at least one BMS is connected to the secondary communication interface of another BMS, then the software may switch to a series pack mode with certain features disabled, such as a contactor control and a current measurement. When BMS is connected to a lead BMS in series connection, and becomes a slave device, it simply becomes a sensing device, and may report cell voltage and temperature measurement data to upper BMS and then cascaded until the data reached the lead BMS. All other BMS functions, such as contactor control, current measurement, state of charge (SoC) / state of health (SoH) estimation, may be disabled. In either the parallel pack mode or the series pack mode, each BMS shares battery measurements with the other BMS, and a leader BMS is automatically assigned to calculate unified data to be exchanged with external controllers. In the series pack mode, a top BMS may be assigned with string leader role, and may aggregate data from all follower BMS to calculate the unified data. In some embodiments, one of the advantages of the parallel and / or series hybrid pack modes is that the operation of the parallel and / or series hybrid pack modes is same as a single BMS. It will also be understood that, one or more embodiments of the present invention is not only for low voltage (LV) BMS, but also for high voltage (HV) BMS where parallelization is more desirable.

[0027] FIG. 1A sets forth a block diagram of a low voltage battery management system diagram of a system 100 in accordance with embodiments of the presentdisclosure. The system includes a low voltage (LV) battery 102 for use in an electric vehicle. LV Battery 102 includes a cell 104, such as Lithium-ion (Li-ion) cells. System 100 may also include a battery management system (BMS) 110. BMS 110 monitors various attributes of cell 104 and provides battery sensor data indicating these attributes to a vehicle control system (VCS) 112 using a wired or wireless communications channel. VCS 112 may include a central “computer” of a vehicle. VCS 112 may be a central control unit or may refer collectively to one or more vehicle subsystems. In an embodiment, VCS 112 includes a battery management system controller (BMSC). MCU 114 may communicate with VCS 112, for example, over a controller area network (CAN) bus or a serial peripheral interface (SPI) bus. MCU 114 may include a universal asynchronous receiver / transmitter (UART) for communicating with VCS 112. The CAN bus is a message-based protocol designed to allow Electronic Control Units (ECUs) found in today's automobiles, as well as other devices, to communicate with each other in a reliable, priority-driven fashion. For bidirectional wireless communication with a wireless network controller, the CMU may include a transceiver coupled to a controller. In some embodiments, LV battery 102 may cover resting voltage up to 120 V.

[0028] FIG. IB sets forth a block diagram of a low voltage battery management system diagram of a system 100 in accordance with embodiments of the present disclosure. The system includes a high voltage (HV) battery 103 for use in the electric vehicle. HV Battery 103 includes a plurality of cell 104 may be grouped into modules 106a-n such that each module 106a-n comprises a corresponding subset of cells 104a- n. System 100 may include a plurality of cell monitoring units (CMU) 108a-n. Cells 104a-n may be physically grouped into modules 106a-n using a casing, chassis, or other enclosure. Cells 104a-n may also be logically grouped into modules 106a-n by virtue of distinct groupings of cells 104a-n being monitored by a distinct CMU 108a-n, as will be described below. Each CMU 108a-n may be configured to monitor a corresponding module 106a-n of cells 104a-n. For example, each module 106a-n may have CMU108a-n attached to a chassis, base, tray, or other mechanism holding cells 104a-n of module 106a-n. Each CMU 108a-n may include sensors to measure various attributes of cells 104a-n of its corresponding module 106a-n. Such attributes may include voltage, current, temperature, and potentially other attributes. The attributes may be indicated in battery sensor data generated by CMU 108a-n. Each CMU 108a-n may be configured to operate at a particular Automotive Safety Integrity Level (ASIL), such as ASIL-D. As an example, each CMU 108a-n may be configured to meet, at minimum, ASIL-QM standards, allowing for reduced cost and complexity.

[0029] Each CMU 108a-n may encode its battery sensor data for transmission and transmits its battery sensor data using a communication channel to a master controller unit (MCU) 114. MCU 114 may include or implement a microcontroller, an Application Specific Integrated Circuit (ASIC), a digital signal processor (DSP), a programmable logic array (PLA) such as a field programmable gate array (FPGA), or other data computation unit in accordance with the present disclosure. MCU 114 then may send the battery sensor data received from CMUs 108a-n to VCS 112 may be a central control unit or may refer collectively to one or more vehicle subsystems. In some other embodiments, MCU 114 may be implemented using a wireless transceiver integrated circuit for reduced cost and complexity. According to some embodiments, the communication channel may have no intervening components between CMU 108a- n and MCU 114, preventing faults from being introduced into the battery sensor data from an intermediary communications component. In some embodiments, HV battery 103 may cover resting voltage above 120 V.

[0030] Referring now to FIG. 2, a schematic 200 illustrating a single BMS in accordance with embodiments of the present disclosure is provided. For example, in one or more embodiments, the BMS (BMS 110 as shown in FIG. 1A) may have two communication interfaces. For example, the communication interfaces may include isolated controller area network (CAN) interfaces: a primary isolated CAN interface 202 and a secondary isolated CAN interface 204 of the BMS. The isolation may beachieved through a combination of capacitive, transformer, and optocoupler. For example, a specific integrated circuit IC ISO6762FQDWRQ1 may also be used to achieve isolation. The BMS may include a battery pack 206 comprising a plurality of battery modules with a transistor switch 208 (a high power contactor) and a ground connection 210. Each of the plurality of battery modules may include a plurality of cells (e.g., a plurality of cells 104a-n, such as Lithium-ion (Li-ion) cells shown in FIG. IB). The BMS may further include one or more cell monitoring unit (e.g., CMU (108a-n) of FIG. IB) such that each of the one or more cell monitoring unit is connected with at least one of the plurality of battery modules for measuring battery characteristic data of the battery modules. In some other embodiments, a wireless BMS may further include one or more module monitoring systems each including at least a sensor for measuring battery characteristic data of the battery modules (at least three cells for cell voltage measurement), a memory unit communicatively coupled to a controller, and a wireless transceiver (not shown). The one or more cell monitoring units may be each configured to encode the battery characteristic data and transmit the battery characteristic data to an external controller.

[0031] Conventional BMS may usually be designed as a standalone system which exchanges information with other controllers in battery powered applications. As the voltage level varies between applications, it may be difficult to develop one BMS to fit all requirements due to the cost and complexity. For example, the low voltage BMS may cover application up to 60V and high voltage BMS may cover application up to 1500V. However, once a battery system is designed and built, it is not easy to expend it to achieve higher power rating or large capacity. Customer may connect multiple battery packs in parallel but that requires an additional controller to aggregate data and coordinate the operation of each BMS. A series connection is generally more difficult due to isolations and lack of software support. Some BMS on the market have limited support of parallel pack connection, but none support series connection nor parallel / series hybrid configuration. One alternative is to use high voltage BMS product(n2 or n3 BMS) to monitor the increased number of battery cells, but the resulting cost is much higher. Additionally, the high voltage BMS may require more space to install which may be difficult for a compact battery system. The description of the isolated CAN interfaces in the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations of the communication interfaces will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure.

[0032] In accordance with various embodiments of the present invention, the low voltage BMS range is a low cost BMS developed for a wide range of applications, ranging from two or three wheelers to material handling and compact energy storage system. One or more embodiments may be applicable to both low voltage and high voltage BMSs. One or more embodiments may require adding a secondary isolated CAN interface as well as some software upgrade. This solution provides the flexibility for customers to connect several battery packs together either in parallel or series without any change to the software installed in the BMS. Each BMS is identical and runs the same software and all BMSs communicate with each other to consolidate the battery measurement data and calculate the unified values. Each BMS may automatically identify and configure itself either as a follower or leader. When BMS is connected to a lead BMS in series connection, and becomes a slave device, it simply becomes a sensing device, and may report cell voltage and temperature measurement data to upper BMS and then cascaded until the data reached the lead BMS. All other BMS functions, such as contactor control, current measurement, state of charge (SoC) / state of health (SoH) estimation, may be disabled. In some embodiments, one automatically assigned leader BMS may aggregate data from each follower BMS to calculate the unified values so that a user may operate the multi-pack system the same way as a single pack system. So for the user, it is the same way to operate either the single pack or the multi-pack system of the BMS.

[0033] Referring now to FIG. 3, a schematic 300 illustrating a parallel pack mode in accordance with embodiments of the present disclosure is shown. In some embodiments, due to an increasing demand on higher power output and larger capacity, it is desirable to connect multiple battery modules in parallel to increase capacity. For example, in one or more embodiments, each BMS 302, 304 and 306 has primary communication interfaces (isolated CAN interfaces as shown in FIG. 2) 303 A, 305 A and 307 A and secondary communication interfaces 303 B, 305 B and 307 B, respectively. In some embodiments, if the primary isolated CAN interfaces 303 A, 305 A and 307 A of each BMS 302, 304 and 306, respectively, of the multiple BMSs are connected together through a CAN bus 308, the software (all BMSs 302, 304 and 306 are running the same software) may switch to a parallel pack mode as shown in FIG. 3.

[0034] Referring now to FIG. 4, a schematic 400 illustrating a series pack mode in accordance with embodiments of the present disclosure is shown. In some embodiments, due to an increasing demand on higher power output, it is desirable to connect multiple battery modules in series to increase voltage level. For example, in one or more embodiments, each BMS 402, 404 and 406 has primary communication interfaces (isolated CAN interfaces as shown in FIG. 2) 403 A, 405 A and 407 A and secondary communication interfaces 403 B, 405 B and 407 B, respectively. In some embodiments, if the primary isolated CAN interface (e.g., 403 A, 405 A) of one BMS (e.g., 402, 404) is connected to the secondary isolated CAN interface (e.g., 405 B, 407 B) of another BMS (e.g., 404, 406) through a CAN bus (e.g., 408A, 408B), then the software (all BMSs 402, 404 and 406 are running the same software) may switch to a series pack mode as shown in FIG. 4. However, in some embodiments, in the series pack mode, certain features such as a contactor control and a current measurement may be disabled. In the series pack mode, a top BMS (e.g., BMS 406) may be assigned with a string leader role, and aggregates data from all follower BMSs (e.g., BMS 402, 404) to calculate the unified data. In some embodiments, in either the parallel pack mode or in the series pack mode, each BMS shares its measurements with other BMSs, and aleader BMS is automatically assigned to calculate unified data to be exchanged with the external controllers.

[0035] The existing BMS product may not be easy to expend to achieve higher power rating or large capacity after a battery system is designed and built. Customer may connect multiple battery packs in parallel but that requires an additional controller to aggregate data and coordinate the operation of each BMS. A series connection is generally more difficult due to isolations and lack of software support. Some BMS on the market have limited support of parallel pack connection, but none support series connection nor parallel / series hybrid pack mode configuration.

[0036] Referring now to FIG. 5, a schematic 500 illustrating a parallel / series hybrid pack mode in accordance with embodiments of the present disclosure is provided. For example, in one or more embodiments, a first series pack mode with BMSs 502, 504 and 506, a second series pack mode with BMSs 512, 514 and 516 and a third series pack mode with BMSs 522, 524 and 526 may be connected in a parallel pack mode through a CAN bus 550 connecting primary isolated CAN interfaces 507 A, 517 A and 527 A of each top BMS 506, 516 and 526, respectively. In some embodiments, a first series pack mode with BMSs 502, 512 and 522, a second series pack mode with BMSs 504, 514 and 524 and a third series and parallel pack mode with BMSs 506, 516 and 526 may be connected in a series pack mode through the primary isolated CAN interface (e.g., 503 A, 505 A, 513 A, 515 A, 523 A, 525 A) of one BMS (e.g., 502, 504, 512, 514, 522, 524) connected to the secondary isolated CAN interface (e.g., 505 B, 507 B, 517 B, 525 B, 526 B) of another BMS (e.g., 504, 506, 514, 516, 524, 526). In some embodiments, the parallel / series hybrid pack mode may have an advantage of providing an operation being same as the single BMS (as shown in FIG. 2).

[0037] In some embodiments, in either parallel or single pack mode, each BMS shares its measurements with other BMS and a leader BMS may be automatically assigned to calculate unified data to be exchanged with the external controllers. In the series pack mode, the top BMS (e.g., 506, 516, 526) may be assigned with string leaderrole, and may aggregate data from all follower BMSs (e.g., 502, 504, 512, 514, 522, 524) to calculate the unified data. One or more embodiments may not only be applicable for low voltage BMS, but also for high voltage system where parallelization is more desirable. The flexibility offered by the parallel / series hybrid pack mode may significantly widen a target market of low voltage BMS products and increase its competitiveness.

[0038] In some embodiments, the solution provided through schematic 500 shown in FIG. 5, may give the flexibility for customers to connect up to any number of battery packs together either in parallel or series without any change to the software. The software runs on each BMS are identical, and all BMSs communicate with each other to consolidate the battery measurement data and calculate the unified values for the BMS in parallel / series hybrid pack mode.

[0039] Referring now to FIG. 6, a flowchart illustrating a method 600 associated with BMS 100 in accordance with embodiments of the present disclosure is shown. In some embodiments, method 600 may include connecting (602) multiple BMSs running on a software in at least one of pack mode configurations using a primary communication interface and a secondary communication interface of at least one BMS. The pack mode configurations include one or more of: a parallel pack mode, a series pack mode, and a parallel / series hybrid pack mode. For example, due to an increasing demand on higher power output and larger capacity, it is desirable to connect multiple battery modules in parallel to increase capacity and in series to increase voltage level. In some embodiments, through a software implementation and a small hardware upgrade, method 600 may include connecting the multiple battery modules in the parallel pack mode, the series pack mode, or the parallel / series hybrid pack mode as shown in FIGs. 3-5. All BMS are running the same software.

[0040] In some embodiments, for example, if primary communication interfaces of the multiple BMSs are connected together, the software of the multiple BMSs switches to the parallel pack mode. For example, in one or more embodiments, if the primaryisolated CAN interfaces 303 A, 305 A and 307 A of each BMS 302, 304 and 306, respectively of the multiple BMSs are connected together through a CAN bus 308, the software (all BMSs 302, 304 and 306 are running the same software) may switch to the parallel pack mode as shown in FIG. 3.

[0041] In some embodiments, for example, if the primary communication interface of the at least one BMS is connected to a secondary communication interface of another BMS, the software of the multiple BMSs switches to the series pack mode. For example, if the primary isolated CAN interface (e.g., 403 A, 405 A) of one BMS (e.g., 402, 404) is connected to the secondary isolated CAN interface (e.g., 405 B, 407 B) of another BMS (e.g., 404, 406) through a CAN bus (e.g., 408A, 408B), then the software (all BMSs 402, 404 and 406 are running the same software) may switch to a series pack mode as shown in FIG. 4.

[0042] In one or more embodiments, for example, if a first series pack mode, a second series pack mode, and a third series pack mode are connected in the parallel pack mode by connecting the primary communication interfaces of each top BMS of the multiple BMSs, the software of the multiple BMSs switches to the parallel / series hybrid pack mode. For example as shown in FIG. 5 for a parallel / series hybrid pack mode, a first series pack mode with BMSs 502, 504 and 506, a second series pack mode with BMSs 512, 514 and 516 and a third series pack mode with BMSs 522, 524 and 526 may be connected in a parallel pack mode through a CAN bus 550 connecting the primary isolated CAN interfaces 507 A, 517 A and 527 A of each top BMS 506, 516 and 526, respectively. In some embodiments, a first series pack mode with BMSs 502, 512 and 522, a second series pack mode with BMSs 504, 514 and 524 and a third series pack mode with BMSs 506, 516 and 526 may be connected in a series pack mode through the primary isolated CAN interface (e.g., 503 A, 505 A, 513 A, 515 A, 523 A, 525 A) of one BMS (e.g., 502, 504, 512, 514, 522, 524) connected to the secondary isolated CAN interface (e.g., 505 B, 507 B, 517 B, 525 B, 526 B) of another BMS (e.g., 504, 506, 514, 516, 524, 526). In some embodiments, the parallel / series hybrid packmode may have an advantage of providing an operation being same as the single BMS (as shown in FIG. 2).

[0043] In some embodiments, the method 600 may also include automatically identifying (604) and configuring each BMS of the multiple BMSs either as a follower BMS or a leader BMS. When BMS is connected to a lead BMS in series connection, and becomes a slave device, it simply becomes a sensing device, and may report cell voltage and temperature measurement data to upper BMS and then cascaded until the data reached the lead BMS. All other BMS functions, such as contactor control, current measurement, state of charge (SoC) / state of health (SoH) estimation, may be disabled.

[0044] In some embodiments, the method 600 may also include aggregating (606) battery measurement data associated with either the follower BMS or the leader BMS to calculate unified data to be exchanged with an external controller. For example, in either the parallel pack mode or in the series pack mode, each BMS shares its measurements with other BMSs, and a leader BMS is automatically assigned to calculate unified data to be exchanged with the external controllers. For example, upon power up, each BMS send out its BMS logic address (start from 0, then 1, 2, 3,...) together with a 7 bytes unique ID (like MAC address). Each BMS then has a table of all the unique IDs from each BMS. Thus, each BMS knows other BMS in a CAN network. The unique ID is then ranked and the BMS with the smallest ID automatically be assigned with lead BMS role. This method may also be used to resolve ID conflicts. If BMS detects two BMS with the same logic ID, it may re-assign logic ID to each BMS according to the ranking order of 7 bytes unique ID. Each BMS uses a few CAN messages to report its measurements data (cell voltage and temperature measurement, pack voltage and current) and its status ( contactor status, SoC / SoH / standard operating procedure (SoP) / standard operating environment (SoE), error / alarm status, BMS mode, etc.). Then, the lead BMS may receive all values from each BMS, it then may calculate the unified values, for example, the current of whole parallel pack is the sumof current reported by each BMS, the SoH is the average SoH, and SoC is the weighted average SoC from each BMS.

[0045] The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0046] The corresponding structures, materials, acts, and equivalents of means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.

[0047] Although a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from the scope of the present disclosure, described herein. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but alsoequivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph (f) for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ or 'step for' together with an associated function.

[0048] Having thus described the disclosure of the present application in detail and by reference to embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the disclosure defined in the appended claims.

Claims

What Is Claimed Is:

1. A method for a battery management system (BMS), the method comprising: connecting multiple BMSs running on a software in at least one of pack mode configurations using a primary communication interface and a secondary communication interface of at least one BMS, wherein the pack mode configurations include one or more of : a parallel pack mode, a series pack mode, and a parallel / series hybrid pack mode; automatically identifying and configuring each BMS of the multiple BMSs either as a follower BMS or a leader BMS; and aggregating battery measurement data associated with either the follower BMS or the leader BMS to calculate unified data to be exchanged with an external controller.

2. The method of claim 1, wherein: if primary communication interfaces of the multiple BMSs are connected together, the software of the multiple BMSs switches to the parallel pack mode, if the primary communication interface of the at least one BMS is connected to a secondary communication interface of another BMS, the software of the multiple BMSs switches to the series pack mode, and if a first series pack mode, a second series pack mode, and a third series pack mode are connected in the parallel pack mode by connecting the primary communication interfaces of each top BMS of the multiple BMSs, the software of the multiple BMSs switches to the parallel / series hybrid pack mode.

3. The method of claim 1, wherein one or more features of the software such as a contactor control and a current measurement are disabled while the software of the multiple BMSs switches to the series pack mode.

4. The method of claim 1, wherein in either the parallel pack mode or the series pack mode, each BMS shares battery measurement data with the other BMS and the leader BMS is automatically assigned to calculate the unified data to be exchanged with the external controller.

5. The method of claim 3, wherein in the series pack mode, the lead BMS is assigned to a top BMS of the multiple BMSs and data from each follower BMS is aggregated to calculate the unified data.

6. The method of claim 2, wherein an operation of the multiple BMSs in the parallel / series hybrid pack mode is same as a single BMS.

7. A battery management system (BMS) comprising: a primary communication interface; a secondary communication interface, wherein the BMS is used with a battery pack comprising a plurality of battery modules and each of the plurality of battery modules comprising a plurality of cells; and a cell monitoring unit configured to measure battery characteristic data of the battery modules, wherein the cell monitoring unit is connected with at least one of the plurality of battery modules, andwherein the cell monitoring unit is configured to encode the battery characteristic data and transmit the battery characteristic data to an external controller.

8. The system of claim 7, wherein: each BMS of the multiple BMSs automatically identifies and configures either as a follower BMS or a leader BMS, and the multiple BMSs running on a software are connected in at least one of pack mode configurations using the primary communication interface and the secondary communication interface of at least one BMS, wherein the pack mode configurations include one or more of: a parallel pack mode, a series pack mode, and a parallel / series hybrid pack mode.

9. The system of claim 8, wherein if primary communication interfaces of the multipleBMSs are connected together, the software of the multiple BMSs switches to the parallel pack mode.

10. The system of claim 9, wherein if the primary communication interface of at least one BMS is connected to a secondary communication interface of another BMS, the software of the multiple BMSs switches to the series pack mode.

11. The system of claim 9, wherein if a first series pack mode, a second series pack mode, and a third series pack mode are connected in the parallel pack mode by connecting the primary communication interfaces of each top BMS of the multiple BMSs, the software of the multiple BMSs switches to the parallel / series hybrid pack mode.

12. The system of claim 10, wherein one or more features of the software such as a contactor control and a current measurement are disabled while the software of the multiple BMSs switches to the series pack mode.

13. The system of claim 10, wherein in either the parallel pack mode or the series pack mode, each BMS shares battery measurement data with other BMS and the leader BMS is automatically assigned to calculate unified data to be exchanged with the external controller.

14. The system of claim 13, wherein in the series pack mode, the leader BMS is assigned to a top BMS of the multiple BMSs and data from each follower BMS is aggregated to calculate the unified data.

15. The system of claim 11, wherein an operation of the multiple BMSs in the parallel / series hybrid pack mode is same as a single BMS.

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