Enhanced Battery Backup Unit Battery Management System

Abstract

The present application discloses an embodiment of a battery management system (BMS). The BMS includes a pair of back-to-back transistors configured to selectively discharge battery cells of a battery pack, a high-side driver configured to control the operation of the pair of back-to-back transistors, an analog front-end (AFE) circuit configured to monitor the voltage of each battery in the battery pack, and a microcontroller unit (MCU) configured to control and monitor the AFE circuit and provide overvoltage protection for the pair of back-to-back transistors.

Description

Technical Field

[0001] The disclosed embodiments relate generally to battery energy storage, and particularly, but not exclusively, to an enhanced battery backup unit (BBU) battery management system (BMS) having a charge / discharge converter. Background Art

[0002] Battery energy storage is a very important energy storage method for many applications such as electric vehicles, consumer electronics, microgrids, solar and wind power, and data center backup units. Battery units provide the necessary energy to support applications as a primary power source or as a backup when the primary power source is unavailable. Therefore, the reliability of battery energy storage is very important to ensure power availability and functionality. Summary of the invention

[0003] In one aspect of the present application, a battery management system is provided. The system may include a pair of back-to-back transistors configured to selectively discharge a battery cell of a battery pack. The system may also include a high-end driver configured to control the operation of a pair of back-to-back transistors. The system may also include an analog front end (AFE) circuit configured to monitor the voltage of each battery in the battery pack. The system may also include a microcontroller unit (MCU) configured to control and monitor the AFE circuit and provide overvoltage protection for a pair of back-to-back transistors. In one embodiment, the system may also include a multi-phase converter connected to a pair of back-to-back transistors and configured to convert the voltage from the battery pack. In one embodiment, the system may also include an overvoltage protection circuit connected to the battery pack and configured to monitor the battery cells of the battery pack. In one embodiment, the system may also include a hot swap circuit connected to the multi-phase converter. In one embodiment, the system may also include two or more multi-phase converters connected in parallel. In one embodiment, the system may also include a first auxiliary power supply connected to the battery pack and a second auxiliary power supply connected to the multi-phase converter. In one embodiment, the first auxiliary power supply may power the system during the discharge of the battery pack, and the second auxiliary power supply may power the system during the standby mode. In one embodiment, the system may further include a fuel gauge connected to the battery pack and the sense resistor and configured to measure the current of the battery pack.

[0004] In another aspect of the present application, an electronic rack is provided. The rack may include a plurality of server chassis, each server chassis including one or more servers. The rack may also include a power supply connected to the server chassis to supply power to the server. The rack may also include a battery backup unit (BBU) having a plurality of battery packs, each battery pack including one or more battery cells, wherein the BBU is configured to supply power to the server when the power supply is unavailable. The rack may also include a battery management system (BMS) connected between the power supply and the server. The BMS includes a pair of back-to-back transistors configured to selectively discharge a plurality of battery cells of the BBU, a high-end driver configured to control the operation of a pair of back-to-back transistors, an analog front end (AFE) circuit configured to monitor the voltage of each battery in the BBU, and a microcontroller unit (MCU) configured to control and monitor the AFE circuit and provide overvoltage protection for a pair of back-to-back transistors.

[0005] In some embodiments, the BMS may further include a multiphase converter connected to a pair of back-to-back transistors and configured to convert a voltage from the BBU. In some embodiments, the BMS may further include an overvoltage protection circuit connected to the BBU and configured to monitor the battery cells of the BBU. In some embodiments, the BMS may further include a hot swap circuit connected to the multiphase converter. In some embodiments, the BMS may further include two or more multiphase converters connected in parallel. In some embodiments, the BMS may further include a first auxiliary power supply connected to the BBU and a second auxiliary power supply connected to the multiphase converter. In some embodiments, the first auxiliary power supply may supply power to the system during BBU discharge, and the second auxiliary power supply may supply power to the system during standby mode. In some embodiments, the BMS may further include a fuel gauge connected to the BBU and a sensing resistor and configured to measure the current of the BBU.

[0006] In another aspect of the present application, a method for managing a battery pack is provided. The method may include monitoring the voltage of each battery in the battery pack using an analog front end (AFE) circuit in a battery management system (BMS); controlling a pair of back-to-back transistors in the BMS to selectively discharge the batteries in the battery pack; and controlling and monitoring the AFE circuit using a microcontroller unit (MCU) in the BMS, wherein the MCU provides overvoltage protection for a pair of back-to-back transistors. In some embodiments, the method may also include using a first auxiliary power supply to power the BMS during discharge of the battery pack, and using a second auxiliary power supply to power the BMS in standby mode. In some embodiments, the method may also include converting the voltage from the battery pack using a multi-phase converter. In some embodiments, the method may also include measuring the battery current of the battery pack using a fuel gauge connected to the battery pack and the AFE circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0008] Figure 1 is a circuit diagram of a battery management system connected to a battery pack and a multi-phase converter according to one embodiment of the present disclosure.

[0009] Figure 2 is a circuit diagram of a simplified battery management system according to one embodiment of the present disclosure.

[0010] Figure 3 An embodiment of a power converter module for bidirectional charging and discharging of a plurality of parallel battery cells according to one embodiment of the present disclosure is shown.

[0011] Figure 4 A flowchart describing a method of controlling a battery management system according to one embodiment of the present disclosure is provided.

[0012] Figure 5 An electronics server rack including a battery backup unit according to another embodiment of the present disclosure has a power converter module having multiple DC buses and multiple battery packs, and bidirectional charging and discharging functions. DETAILED DESCRIPTION

[0013] The design of a battery management system (BMS) and implementation of a charge / discharge converter with recommended components are described. The BMS can be used to manage a lithium-ion battery system used as energy storage. In some embodiments, the BMS can be employed in a data center battery backup unit (BBU), an electric bicycle, or other electronic devices that can employ a lithium-ion battery system as energy storage.

[0014] Throughout the specification, references to "one embodiment" or "an embodiment" mean that the described features, structures, or characteristics may be included in at least one of the described embodiments, and thus, the appearances of "in one embodiment" or "in an embodiment" do not necessarily all refer to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics may be combined in any suitable manner.

[0015] The present disclosure provides a BMS design that can be applied to various lithium-ion battery packs. In some embodiments, the BMS covers monitoring, protection and control functions. For example, the BMS can monitor the voltage, current, battery and battery pack temperature, state of charge (SOC) and state of health (SOH) of the battery pack. In some embodiments, depending on the monitoring parameters, the BMS may include overvoltage protection, overcurrent protection, over-temperature protection, and undervoltage protection through battery balancing and charge / discharge control.

[0016] The proposed BMS can be used for various types of battery packs. Depending on the battery pack voltage range, different chips can be used. In some embodiments, the BMS may include a backup auxiliary power supply that can increase its resilience when external power is lost. In the event of a failure of the microcontroller unit (MCU), the BMS may include separate analog overvoltage protection in addition to digital control. In some embodiments, the BMS may also include hot-swap circuits for BBU applications. However, this is optional as the battery is not plugged in or unplugged during discharge. In some embodiments, multiple converters can be connected in parallel for high power applications. Figure 1 In the illustrated embodiment, only one converter is shown, although the converter itself may be optional and multiple converters may be used.For battery applications, the designs disclosed herein may be implemented at the unit level in a rack or in a battery or fuel cell rack.

[0017] In one embodiment, the battery packs are connected via back-to-back switches. They are then connected to a multi-phase four-switch buck-boost converter for voltage conversion. The converter is then connected to a hot-swap circuit to enable hot-swap functionality. The hot-swap circuit is then connected to a fuse and then to a bus connection. High current, low temperature coefficient resistors can be used as sense resistors. Two auxiliary power supplies are connected at the battery terminals and bus terminals, respectively, for redundancy.

[0018] Figure 1 1 is a circuit diagram of a battery management system connected to a battery pack 101 and a multi-phase converter 117 according to one embodiment of the present disclosure. In this embodiment, the battery pack 101 is connected to multiple circuits, including an analog front end (AFE) 109, an overvoltage protection circuit 107, and a pair of back-to-back transistors 103 connected to a high-side driver 105. In some embodiments, a second pair of back-to-back transistors is connected to a second high-side driver, and a first auxiliary power supply AuxP1 113 is located between the back-to-back transistor groups.

[0019] In some embodiments, if there is only one pair of auxiliary power supplies, and the auxiliary power supplies are short-circuited, two sets of back-to-back transistors on both sides of the first auxiliary power supply Aux P1 113 help prevent short circuits. In this embodiment, the first auxiliary power supply Aux P1 113 is located between the first pair of back-to-back transistors 103 and the second pair of back-to-back transistors, and when the second auxiliary power supply Aux P2 119 is turned off (the power from the bus is turned off), both the first pair of back-to-back transistors 103 and the second pair of back-to-back transistors are in a conductive state while the first auxiliary power supply Aux P1 113 provides auxiliary power to the controller and other lines. If the battery power is cut off and no power is provided from the bus, the first pair of back-to-back transistors 103 and the second pair of back-to-back transistors can be used alternately to power the first auxiliary power supply Aux P1 113, so that the controller and other auxiliary functions can still be powered for monitoring and communication purposes.

[0020] exist Figure 1 In an embodiment, AFE 109 is a circuit that includes a main monitoring circuit with an ADC and (optionally) a battery balancing circuit. For example, if TI BQ76940 is selected in one design, it can support 9 to 15 batteries connected in series, suitable for BBU design in a data center. AFE 109 may include a separate ADC for voltage monitoring of each battery. It may also have a battery balancing circuit for each battery in series. In this embodiment, AFE 109 is connected to a paired MCU 115 via I2C communication and I / O.

[0021] exist Figure 1 In the embodiment shown, a fuel gauge 111 is connected to a sense resistor 112 to measure the battery current. The reading from the fuel gauge 111 is then sent to the MCU 115 via I2C communication. The AFE 109 can be equipped with a fuel gauge 111 for monitoring. A direct read separate connection to the MCU 115 can be used for fast response for control and protection purposes. In some embodiments, the fuel gauge 111 is optional because the MCU 115 can have its own algorithms and I / O for sensing.

[0022] In some embodiments, an optional overvoltage protection circuit 107 may be implemented. The overvoltage protection circuit 107 may be used to monitor each group of battery cells (e.g., 2 to 5 battery cells in series) to send an analog signal to the corresponding switch to open the circuit when an overvoltage condition is reached. If enabled, the TI BQ7718 may be selected. A self-controlled protector (SCP) may also be added as additional protection, such as the SFM-50120.

[0023] In this embodiment, the high-side driver 105 is connected to a pair of transistors 103 to drive back-to-back MOSFETs. In an example embodiment, a BQ 76200 driver can be used, and other similar drivers such as LTC1154 or others can also be used. The switching signal is controlled by the MCU 115 through the I / O.

[0024] In this embodiment, the MCU 115 is paired with the AFE 109 to handle the control, protection and monitoring processes. The MCU 115 also handles all communications within the system. A separate MCU can be used to control the multi-phase converter 117, which is omitted here because it can be a group for the converter 117 itself. In one embodiment, the battery pack 101 is connected to a multi-phase converter 117 (such as a multi-phase four-switch buck-boost converter) through back-to-back transistors 103 to convert voltage. The converter 117 can be connected to a hot swap circuit 121, which is in turn connected to a fuse 123 and then to a bus connection. In one embodiment, the hot swap circuit 121 is optionally configured to handle hot swapping of battery cells (e.g., insertion and removal during operation), that is, inrush current or overvoltage caused by hot insertion or removal.

[0025] Two auxiliary power supplies Aux P1 113 and AUX P2 119 can be connected to the battery terminals and the bus terminals, respectively, to provide redundancy. The auxiliary power can be provided from the battery at Aux P1 113 or the bus at Aux P2 119 by corresponding circuits. Converter 117 can be used to convert the battery or bus voltage to the required auxiliary voltage, such as 5V or 3.3V. Insulation is recommended. For example, the LM5164 with TLV70433 can be deployed for 3.3V applications, while the TLV70450 with an isolation converter can be used for 5V lines for communication applications. In this exemplary embodiment, Aux P1 113 can power the system during discharge of the battery pack 101, while Aux P2119 can power the system in standby or sleep mode.

[0026] In some embodiments, Figure 1 The BMS disclosed in the can be integrated into battery energy storage in various situations, including but not limited to, data center rack level with single or multiple DC buses, data center UPS battery room, electric vehicles (including hybrid), consumer electronics, and medical devices. The BMS can also be integrated into a server or edge computing device. In some embodiments, additional switches can be added in series with the fuse 123 to provide additional protection and can be controlled by the MCU 115 or the overvoltage protection circuit 107. In some embodiments, the multi-phase four-switch converter 117 can be replaced by an insulated or non-insulated charge and discharge converter.

[0027] Figure 2 2 is a simplified circuit diagram of a BMS 200 according to one embodiment of the present disclosure. In this embodiment, the BMS 200 includes an AFE 209 connected to an MCU 215, and a high-side driver 205 and a pair of back-to-back transistors 203 connected to the MCU 215. The BMS 200 includes connectors so that the transistors 203 can be connected to the battery pack and the converter, such as Figure 1 As shown, AFE 209 may also be connected to the battery pack. As described above, in this embodiment, AFE 209 may include an ADC and (optionally) a battery balancing circuit. In this embodiment, AFE 209 is connected to MCU 215 via I2C communication and I / O. In this embodiment, high-side driver 205 is connected to a pair of back-to-back transistors 203 to provide control of the MOSFET. The switching signal can be controlled by MCU 215 via I / O.

[0028] Figure 3 An embodiment of a power converter module 300 for bidirectional charging and discharging of multiple parallel battery cells is shown. In some embodiments, Figure 1 The converter 117 shown in FIG. Figure 3 . The power converter module 300 shown in FIG. The power converter module 300 may include a DC bus selection circuit 310, a battery pack selection circuit 320, and one or more converter circuits 330 connected between the DC bus selection circuit 310 and the battery pack selection circuit 320. The DC bus selection circuit 310 may include a set of one or more bidirectional switches or switch circuits 312A, 312B, multiple bidirectional switches or switch circuits are connected in parallel and each is connected to a separate DC bus or other external connection, for example, an external load or an external power source. The bidirectional switches 312A, 312B can be used to select one or more DC buses or external connections to charge or discharge the battery packs 352A, 352B. That is, each switch 312A, 312B can be switched separately between an external load (e.g., a server of an electronic rack) and / or a power source.

[0029] In addition, the DC bus selection circuit 310 may include one or more bidirectional switches 314 connected in parallel with the bidirectional switches 312A, 312B. The bidirectional switches 314 may be connected to an internal load 315, such as a resistor or other electronic component / circuit. The bidirectional switches 314 may be used to select a low power self-test mode in which various aspects of the power converter module 300 are monitored while discharging one or more battery cells through the internal load 315. Within the size of the power converter module 300, multiple bidirectional switches may be included in parallel with 312A, 312B to provide any number of external connections.

[0030] The battery pack selection circuit 320 may include a main bidirectional switch 322, which is connected in series with one or more bidirectional switches or switch circuits 324A, 324B arranged in parallel. The main bidirectional switch 322 can be used to switch between a battery pack balancing mode and other modes. Bidirectional switches 324A, 324B can each be connected to a separate battery pack (e.g., battery packs 352A, 352B as shown). Bidirectional switches 324A, 324B can be used to select one or more battery packs 352A, 352B for charging, discharging or balancing. It should be noted that within the size of the power converter module 300, any number of bidirectional switches can be included in parallel with 324A, 324B to provide any number of battery pack connections. The converter circuit 330 can be any type of converter, such as a four-switch buck-boost converter or other DC-DC converter. In one embodiment, the converter circuit 330 may include multiple converters connected in parallel to accommodate DC bus power requirements.

[0031] The power converter module 300 may also include a control circuit 340 having a control logic 345 for controlling each bidirectional switch to set the operating mode in which the power converter module 300 is located. When the operating mode should be selected, the operating mode is selected by the control logic 345 based on a predetermined heuristic (such as a conditional definition). For example, if the charge of the battery pack drops below a certain level when a DC power source is available, a charging mode may be selected. Similar rules may be defined for each operating mode. An administrator may also manually select an operating mode. Although the control circuit 340 is described as being external to the power converter module 300, the control circuit 340 may also be included in the power converter module 300.

[0032] Figure 4 4 is a flow chart of a method for controlling a battery management system according to one embodiment of the present disclosure. Process 400 may be performed by hardware, software, or a combination thereof. Process 400 may be performed by processing logic of the MCU 115, AFE 109, or some other combination of circuits described in the present disclosure. In operation 401, the AFE circuit monitors the voltage of each battery in the battery pack. As described above, the AFE may include an ADC and (optionally) a battery balancing circuit. The AFE may include a separate ADC for monitoring the voltage of each battery. For each battery connected in series, it may also have a battery balancing circuit.

[0033] In operation 403, a pair of back-to-back transistors in the BMS are controlled to selectively discharge the batteries in the battery pack. In some embodiments, the back-to-back transistors may include a pair of MOSFETs, and a high-side driver is connected to the transistors to control their operation. In some embodiments, a first auxiliary voltage circuit at the battery terminals supplies power to the BMS during battery pack discharge, and a second auxiliary voltage circuit at the bus terminals supplies power to the BMS during standby mode.

[0034] In operation 405, the MCU in the BMS controls and monitors the AFE circuit and provides overvoltage protection for the back-to-back transistors. In some embodiments, the AFE circuit includes an ADC and a cell balancing circuit.

[0035] In operation 407, a multiphase converter may be used to convert the voltage from the battery pack. The converter may be used to convert the battery or bus voltage to a desired auxiliary voltage, such as 5V or 3.3V. In some embodiments, multiple converters may be connected in parallel for high power applications. The converter circuit may be any type of converter, such as a four-switch buck-boost converter or other DC-DC converter. In one embodiment, the converter circuit may include multiple converters connected in parallel to accommodate DC bus power requirements.

[0036] In operation 409, the battery current of the battery pack is measured using a fuel gauge connected to the battery pack and the AFE circuit. In some embodiments, the fuel gauge can be connected to a sense resistor to measure the battery current. In some embodiments, a separate fuel gauge is optional because the MCU can have its own algorithm and I / O for sensing.

[0037] Figure 55 is a block diagram showing an example of an electronic rack 500 with a BBU rack 555 according to one embodiment. The BBU rack 555 may include a power converter module 117 as described above. The electronic rack 500 may include one or more server slots to accommodate one or more servers, respectively. Each server includes one or more information technology (IT) components (e.g., processors, memories, storage devices, network interfaces). According to one embodiment, the electronic rack 500 includes, but is not limited to, a CDU 501, a rack management unit (RMU) 502 (optional), a power supply unit (PSU) 550, a BBU rack 555, and one or more IT devices (or IT devices) 503A to 503D, which may be any type of IT device, such as a blade server. The IT device 503 may be inserted into the server slot array from the front end 504 or the rear end 505 of the electronic rack 500, respectively. The PSU 550 and / or the BBU rack 555 may be inserted into any server slot within the electronic rack 500. In one embodiment, the BBU rack 555 can be inserted into any server slot within the electronics rack 500. In another embodiment, the BBU rack 555 can be inserted into several slots (e.g., occupying two or more slots within the rack). As shown, the BBU rack 555 can be inserted at the bottom of the rack (below the PSU 550). In one embodiment, along with or in lieu of the BBU rack, the rack can house one or more BBUs.

[0038] In one embodiment, the BBU rack 555 may include a power converter module 117. The power converter module 117 may be modularly connected to or disconnected from the BBU rack 555. For example, the BBU rack 555 may include a DC bus connection for the power converter module 117 to be connected. Then, the battery packs may be inserted into the power converter modules 117 in the BBU rack 555, respectively.

[0039] It should be noted that although only three IT devices 503A to 503C are shown here, more or fewer IT devices can be maintained in the electronics rack 500. It should also be noted that the specific locations of the CDU 501, RMU 502, PSU 550, BBU rack 555, and IT devices 503 are shown for illustration purposes only. Other arrangements or configurations of these components can also be implemented. It should be noted that the electronics rack 500 can be open to the environment or partially contained in a rack container as long as the cooling fans can generate airflow from the front to the rear (or generate airflow from the rear to the front).

[0040] In addition, fan modules may be associated with each of the IT equipment 503 and the BBU rack 555. In the present embodiment, the fan modules 531A to 531E are collectively referred to as fan modules 531 and are associated with the IT equipment 503A to 503D and the BBU rack 555, respectively. Each fan module 531 includes one or more cooling fans. The fan module 531 may be mounted on the rear end of the IT equipment 503 and / or the BBU rack 555 to generate an airflow that flows from the front end 504, through the rack 500, and is present at the rear end 505 of the electronic rack 500. In another embodiment, one or more fan modules may be placed on the front end 504 of the rack 500. Such front end fans may be configured to push air into the IT equipment 503 and / or the BBU rack 555.

[0041] In one embodiment, the CDU 501 mainly includes a heat exchanger 511, a liquid pump 512 and a pump controller (not shown) and some other components (such as a liquid reservoir, a power supply, a monitoring sensor, etc.). The heat exchanger 511 can be a liquid-liquid heat exchanger. The heat exchanger 511 includes a first loop having an inlet and an outlet, and the inlet and outlet have a first pair of liquid connectors, which are connected to external liquid supply / return lines 532 to 533 to form a main loop. The connectors connected to the external liquid supply / return lines 532 to 533 can be set or installed on the rear end 505 of the electronic rack 500. The liquid supply / return lines 532 to 533 are connected to a set of room manifolds, which are connected to an external heat removal system or an external cooling loop. In addition, the heat exchanger 511 also includes a second loop having two ports with a second pair of liquid connectors, which are connected to the liquid manifold 525 to form a second loop, which may include a supply manifold for supplying cooling liquid to the IT equipment 503 and a return manifold for returning warmer liquid to the CDU 501. It should be noted that the CDU 501 can be any kind of CDU that can be commercially available or customized. Therefore, the details of the CDU 501 will not be described herein.

[0042] Each IT device 503 may include one or more IT components (e.g., a central processing unit or CPU, a graphics processing unit (GPU), memory, and / or storage device). Each IT component may perform data processing tasks, wherein the IT component may include software installed in a storage device, loaded into memory, and executed by one or more processors to perform data processing tasks. At least some of these IT components may be connected to the bottom of any cooling device. The IT device 503 may include a host server (referred to as a host node) connected to one or more computing servers (also referred to as computing nodes, such as CPU servers and GPU servers). The host server (with one or more CPUs) typically interfaces with a client over a network (e.g., the Internet) to receive requests for specific services such as storage services (e.g., cloud-based storage services such as backup and / or restore), and execute applications to perform certain operations (e.g., image processing, deep data learning algorithms or modeling, etc. as part of a software as a service or SaaS platform). In response to the request, the host server assigns the task to one or more performance computing nodes or computing servers (with one or more GPUs) managed by the host server. The performance computing server performs the actual task, which may generate heat during operation.

[0043] In one embodiment, the BBU rack 555 is configured to provide backup power (e.g., drawing battery power from one or more BBUs included therein) to the rack (e.g., one or more IT devices 503) when the rack is unable to draw power from a primary power source (e.g., during a power outage). In one embodiment, operations performed by the controller of the BBU rack 555 (e.g., selecting an operating mode and monitoring sensor data) may be performed by any component within the rack 500 (e.g., IT device 503A).

[0044] The electronic rack 500 also includes an optional RMU 502 configured to provide and manage power provided to the servers 503, the fan modules 531, and the CDU 501. In some applications, the optimization module 521 and the RMC 522 can communicate with the controller. The RMU 502 can be connected to the PSU 550 to manage the power consumption of the PSU 550. The PSU 550 can include necessary circuits (e.g., alternating current (AC) to direct current (DC) or DC to DC power converters, backup batteries, transformers or regulators, etc.) to power the remaining components of the electronic rack 500.

[0045] Note that some or all of the components shown and described above may be implemented in software, hardware, or a combination thereof. For example, such a component may be implemented as software installed and stored in a permanent storage device, which may be loaded and executed by a processor (not shown) in a memory to perform the processes or operations described throughout the application. Alternatively, such a component may be implemented as executable code programmed or embedded in dedicated hardware, such as an integrated circuit (e.g., an application-specific integrated circuit or ASIC), a digital signal processor (DSP), or a field programmable gate array (FPGA), which may be accessed from an application program via a corresponding driver and / or operating system. In addition, such a component may be implemented as dedicated hardware logic in a processor or processor core as part of an instruction set accessible by a software component via one or more dedicated instructions.

[0046] Some portions of the foregoing detailed description have been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of operations leading to a desired result. These operations are those requiring physical manipulations of physical quantities.

[0047] It should be remembered, however, that all of these terms and similar terms will be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. It should be understood that, unless otherwise clearly indicated from the above discussion, throughout the specification, discussions utilizing terms such as those set forth in the following claims refer to actions and processes of a computer system or similar electronic computing device that manipulates and transforms data represented as physical (electronic) quantities in the computer system's registers and memories into other data similarly represented as physical quantities within the computer system's memories or registers or other such information storage, transmission or display devices.

[0048] Embodiments of the present disclosure also relate to devices for performing the operations described herein. Such a computer program is stored in a non-transitory computer-readable medium. A machine-readable medium includes any mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a machine-readable (e.g., computer-readable) medium includes a machine (e.g., computer) readable storage medium (e.g., a read-only memory ("ROM"), a random access memory ("RAM"), a magnetic disk storage medium, an optical storage medium, a flash memory device).

[0049] The processes or methods described in the foregoing figures may be performed by processing logic, wherein the processing logic includes hardware (e.g., circuits, dedicated logic, etc.), software (e.g., embodied on a non-transitory computer-readable medium), or a combination of both. Although the processes or methods are described above in terms of some sequential operations, it should be understood that some of the operations described may be performed in a different order. In addition, some operations may be performed in parallel rather than sequentially.

[0050] The embodiments of the present disclosure are not described with reference to any particular programming language. It will be appreciated that a variety of programming languages ​​may be used to implement the teachings of the embodiments of the present disclosure as described herein.

[0051] In the foregoing description, embodiments of the present disclosure have been described with reference to specific exemplary embodiments of the present disclosure. It will be apparent that various modifications may be made thereto without departing from the broader spirit and scope of the present disclosure as set forth in the appended claims. Therefore, the description and drawings are illustrative rather than restrictive.

Claims

1. Battery management system, including: a first pair of back-to-back transistors configured to selectively discharge battery cells of a battery pack; a first high-side driver configured to control operation of the first pair of back-to-back transistors; a second pair of back-to-back transistors; a second high-side driver connected to the second pair of back-to-back transistors; an analog front end circuit configured to monitor the voltage of each of the battery cells in the battery pack; a microcontroller unit configured to control and monitor the analog front end circuit and provide overvoltage protection for the first pair of back-to-back transistors and the second pair of back-to-back transistors; a first auxiliary power supply, located between the first pair of back-to-back transistors and the second pair of back-to-back transistors, configured to supply power to the battery management system during discharge of the battery pack; as well as a second auxiliary power source configured to supply power to the battery management system during a standby mode of the battery pack; Wherein, when the second auxiliary power supply is turned off, the first pair of back-to-back transistors and the second pair of back-to-back transistors are both in a conducting state while the first auxiliary power supply provides auxiliary power to the microcontroller unit and other circuits. 2 . The system of claim 1 , further comprising a multi-phase converter connected to the first pair of back-to-back transistors or the second pair of back-to-back transistors and configured to convert a voltage from the battery pack. 3 . The system according to claim 2 , further comprising an overvoltage protection circuit connected to the battery pack and configured to monitor the voltage of the battery cells of the battery pack.

4. The system of claim 2, further comprising a hot swap circuit connected to the multi-phase converter.

5. The system of claim 2, further comprising two or more of the multi-phase converters connected in parallel.

6. The system according to claim 2, wherein: The first auxiliary power source is connected to the battery pack, and the second auxiliary power source is connected to the multi-phase converter. 7 . The system of claim 1 , further comprising a fuel gauge connected to the battery pack and a sense resistor and configured to measure a current of the battery pack.

8. Electronic rack, including: A plurality of server chassis, each of the server chassis comprising one or more servers; a power supply connected to the server chassis to supply power to the plurality of servers; a battery backup unit having a plurality of battery packs, each of the battery packs including one or more battery cells, wherein the battery backup unit is configured to provide power to the plurality of servers when the power source is unavailable; and A battery management system is connected between the power source and the plurality of servers, and the battery management system includes: a first pair of back-to-back transistors configured to selectively discharge the plurality of battery cells of the battery backup unit; a first high-side driver configured to control operation of the first pair of back-to-back transistors; a second pair of back-to-back transistors; a second high-side driver connected to the second pair of back-to-back transistors; an analog front end circuit configured to monitor the voltage of each of said battery cells within said battery backup unit; a microcontroller unit configured to control and monitor the analog front end circuit and provide overvoltage protection for the first pair of back-to-back transistors and the second pair of back-to-back transistors; a first auxiliary power supply disposed between the first pair of back-to-back transistors and the second pair of back-to-back transistors, configured to supply power to the battery management system during discharge of the battery backup unit; and a second auxiliary power source configured to provide power to the battery management system during a standby mode of the battery backup unit; Wherein, when the second auxiliary power supply is turned off, the first pair of back-to-back transistors and the second pair of back-to-back transistors are both in a conducting state while the first auxiliary power supply provides auxiliary power to the microcontroller unit and other circuits.

9. The electronic rack according to claim 8, wherein: The battery management system further includes a multi-phase converter connected to the first pair of back-to-back transistors or the second pair of back-to-back transistors and configured to convert a voltage from the battery backup unit.

10. The electronic rack according to claim 9, wherein: The battery management system further includes an overvoltage protection circuit connected to the battery backup unit and configured to monitor the battery cells of the battery backup unit.

11. The electronic rack according to claim 9, wherein: The battery management system also includes a hot swap circuit connected to the multi-phase converter.

12. The electronic rack according to claim 9, wherein: The battery management system further includes two or more of the multi-phase converters connected in parallel.

13. The electronic rack according to claim 9, wherein: The first auxiliary power source is connected to the battery backup unit, and the second auxiliary power source is connected to the multi-phase converter.

14. The electronic rack according to claim 8, wherein: The battery management system also includes a fuel gauge connected to the battery backup unit and a sense resistor and configured to measure a current of the battery backup unit.

15. A method for managing a battery pack, the method comprising: Using an analog front-end circuit in a battery management system to monitor the voltage of each battery cell in the battery pack; controlling a first pair of back-to-back transistors within the battery management system to selectively discharge the battery cells within the battery pack; Controlling and monitoring the analog front end circuit using a microcontroller unit within the battery management system, wherein the microcontroller unit provides overvoltage protection for the first pair of back-to-back transistors and the second pair of back-to-back transistors; During discharge of the battery pack, powering the battery management system using a first auxiliary power source, the first auxiliary power source being located between the first pair of back-to-back transistors and the second pair of back-to-back transistors; and During the battery pack standby mode, a second auxiliary power supply is used to power the battery management system, wherein, when the second auxiliary power supply is turned off, the first pair of back-to-back transistors and the second pair of back-to-back transistors are in an on state while the first auxiliary power supply provides auxiliary power to the microcontroller unit and other circuits.

16. The method according to claim 15, further comprising: The voltage from the battery pack is converted using a multi-phase converter.

17. The method according to claim 15, further comprising: A battery current of the battery pack is measured using a fuel gauge connected to the battery pack and the analog front end circuit.

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