A series battery management system, management method, communication method, and medium

Abstract

This invention provides a series battery management system, management method, communication method, and medium. The system assigns a battery controller to each battery cell in the series battery pack. These battery controllers are connected in series via a communication link and communicate with an MCU controller. Both the MCU controller and the battery controllers operate in a low-voltage power domain and use a non-isolated interface for data transmission. The method includes acquiring the power information of each battery cell to determine its operating mode; adjusting the switching states in the battery controllers to achieve battery access switching and ensure power supply to the level converters and digital logic circuits; and simultaneously performing adaptive level conversion based on the potential difference between adjacent battery controllers using the level converters. In this invention, all chips operate in a low-voltage power domain, resulting in a fast system response speed. The system is not limited by the number of series battery packs and has good scalability, making it suitable for battery management in electric vehicles, energy storage, and other fields.

Description

Technical Field

[0001] This invention relates to the field of power management, and more specifically, to a series battery management system, management method, communication method, and medium. Background Technology

[0002] In electronic devices or battery storage devices, as the total battery capacity increases, series battery pack systems are often used without changing the system's rated current. However, due to the inconsistency of the series batteries, the effective total battery capacity decreases. Therefore, common-mode patents "A Battery Management System and Method" and "A Chip Management System for Multi-cell Series Structure" propose using a set of switches to bypass the battery. This not only solves the problem of reduced effective capacity of the series battery pack caused by the performance degradation of a single cell, but also avoids the failure of the entire battery pack due to the failure of a single cell. In addition, the switching method can achieve the effects of fast charging and deep discharging of the entire battery pack.

[0003] In multi-series battery pack system management, a high-voltage battery management simulation front-end chip is often used to measure the battery pack and transmit the measured values ​​to the system's control chip; for example... Figure 1 The current communication methods have the following main drawbacks:

[0004] 1. In this high-voltage architecture, the voltage withstand capability of the high-voltage battery management analog front-end chip is often limited. For example, for an analog front-end chip with a withstand voltage of 80V, assuming the highest voltage of the battery is 4.3V, a single voltage-resistant chip can only measure a maximum of 18 battery cells. When the number of battery cells in series exceeds 18, an additional chip is required for measurement.

[0005] 2. As the number of series-connected battery packs continues to increase, more high-voltage chips are required, the system connection becomes more complex, and routing a large number of high-voltage lines on the board becomes very difficult.

[0006] 3. A BMS typically includes an MCU to perform system monitoring and charge / discharge management. The MCU operates in a low-voltage domain and needs to be isolated for different voltage levels when communicating with each battery cell. Due to the inconsistency of battery characteristics, the voltage of each cell varies greatly, making reliable isolation of the communication system very complex.

[0007] 4. If the connection between the battery and AFE is faulty, measurements will be impossible, leading to battery management failure.

[0008] 5. Currently, BMS communication systems lack standard protocols, and products from different vendors are incompatible with each other, resulting in software that cannot be used across platforms and wasting a lot of human and material resources on repeated software development.

[0009] Therefore, how to avoid high-voltage environments, achieve effective management and reliable communication of large-scale series batteries, and ensure the safe and reliable operation of the entire system is an urgent problem to be solved. Summary of the Invention

[0010] The purpose of this invention is to address the problems of effective management and reliable communication of large-scale series-connected batteries by proposing a series-connected battery management system, management method, and communication method. In this invention, all chips operate in a low-voltage power domain, all interfaces are non-isolated, and the MCU (Microcontroller Unit) acts as the master controller, managing all battery pack controllers. Due to its all-low-voltage characteristics, the system has a fast response speed and is not limited by the number of series-connected battery packs, exhibiting good scalability. It can effectively manage large-scale series-connected battery packs and is suitable for battery management in fields such as electric vehicles and energy storage.

[0011] The technical solution of this invention is:

[0012] In a first aspect, the present invention provides a series battery management system, including an MCU controller and a battery controller configured for each battery in the series battery. Each battery controller is connected in series via a communication link and communicates with the MCU controller. The battery controller closest to the MCU controller is set as the first level, and the battery controller furthest from the MCU controller is set as the Nth level. The MCU controller and each battery controller operate in a low-voltage power domain and use a non-isolated interface for data transmission.

[0013] The battery controller includes switch A, switch B, switch C, switch D, digital logic circuitry, and level converter.

[0014] Switch A is connected in series with the battery to form a branch, and switch B is connected in parallel with the series branch formed by switch A and the battery. Switches A and B are used to control whether the battery is connected.

[0015] One end of switch C is connected to the connection point between switch A and the battery. The other end of switch C is connected to the power supply terminal of the digital logic circuit on one side and to the connection point between switch D and switch D in the adjacent lower-level battery controller on the other side. The switches D of the adjacent battery controllers are connected in series. The switches C and D are used to control the power supply mode and communication level setting of the digital logic circuit.

[0016] The digital logic circuit is connected to the level converter via a bidirectional communication link. The power supply terminal of the level converter is connected to both ends of switch D. The level converters of adjacent battery controllers are connected in series via a bidirectional communication link.

[0017] The MCU controller is used to collect the power information of each battery, determine the working mode of the corresponding battery based on the power information, adjust the switch state in the battery controller, realize battery access switching, and ensure the power supply of the level converter and digital logic circuit.

[0018] Furthermore, an adaptive communication level conversion based on the potential difference between adjacent battery controllers is achieved through a level converter. The two ends of the level converter are high and low levels, respectively. When the battery is normally connected, the high and low levels differ by one battery voltage. When the battery is bypassed, the voltages at both ends of the level converter are the same, thus realizing communication between different levels of battery controllers.

[0019] Secondly, the present invention provides a management method for a series battery management system, wherein each battery in the series battery is configured with a corresponding battery controller, and each battery controller is connected in series via a communication link and communicates with an MCU controller; both the MCU controller and the battery controller operate in the low-voltage power domain and use a non-isolated interface for data transmission; the management method includes:

[0020] The MCU controller obtains the power information of each cell in the series battery through the serial communication link, and determines the working mode of the corresponding cell based on the power information.

[0021] Adjust the switch state in the battery controller according to the battery's operating mode to achieve battery access switching and ensure power supply to the level converter and digital logic circuit.

[0022] Meanwhile, adaptive level conversion is performed by a level converter based on the potential difference between adjacent battery controllers. The two ends of the level converter are high and low levels, respectively. When the battery is normally connected, the high and low levels differ by one battery voltage. When the battery is bypassed, the voltages at both ends of the level converter are the same, realizing communication between different levels of battery controllers.

[0023] Furthermore, adjusting the switch state in the battery controller according to the battery's operating mode to achieve battery access switching and ensure power supply to the level converter and digital logic circuit includes:

[0024] Detect battery power information;

[0025] If in normal working mode, select switch A and switch C to connect the battery. The high level of this battery is connected to the digital logic circuit and the low level of the level converter through the switches A and C. The high level of the level converter is powered by the upstream battery, ensuring that the level converter and digital logic circuit work normally.

[0026] If in an abnormal operating mode, select switch B and switch D to bypass the battery. Then, connect the power supply of the upstream battery to the digital logic circuit and the high and low levels of the level converter through switches B and D to ensure that the level converter and digital logic circuit work normally.

[0027] Furthermore, adaptive level conversion based on the potential difference between adjacent battery controllers via a level converter includes:

[0028] Obtain the low level VB_n and high level VC_n of the nth battery, 1≤n≤N, and calculate the voltage V0 of a single battery cell.

[0029] When the battery is connected;

[0030] The supply voltage of the nth level digital logic circuit is equal to the low level of the nth level battery plus the voltage of a single battery cell, i.e., VDD_n = VC_n = VB_n + V0;

[0031] The low level of communication in the nth level digital logic circuit is equal to the low level of the nth level battery plus the single-cell battery voltage VL_n = VB_n + V0; the high level of communication is equal to the low level of the nth level battery plus twice the single-cell battery voltage VH_n = VB_n + 2*V0.

[0032] When the battery is bypassed;

[0033] The nth level digital circuit is powered by the (n+1)th level, i.e., VDD_(n) = VL_n+1 = VB_n+1 + V0 = VB_n + V0;

[0034] The communication low level and the communication high level are both equal to the low level of the nth battery plus the single cell voltage VL_n = VH_n = VB_n + V0;

[0035] Based on the potential difference of the communication level, a level converter is used to shift the signal level up, down, or horizontally to achieve normal communication with the adjacent battery controller.

[0036] Furthermore, the step of using a level converter to shift the signal level up, down, or horizontally based on the potential difference of the communication level includes:

[0037] When the battery is connected, the level converter shifts the digital signal level output by the nth stage up by one cell battery voltage to match the communication level of the (n+1)th stage; or the level converter shifts the digital signal level output by the (n+1)th stage down by one cell battery voltage to match the communication level of the nth stage.

[0038] When the battery is bypassed, the level converter shifts and converts the digital signal level output by the nth stage to maintain the same communication level as the (n+1)th stage.

[0039] Thirdly, the present invention provides a computer-readable storage medium on which a computer program is stored, and which, when executed by a processor, implements the management method described above.

[0040] Fourthly, the present invention provides a communication method for the series battery management system, wherein the communication link uses a bidirectional communication line for data transmission, the bidirectional communication lines serve as backups for each other, and full-duplex mode or half-duplex mode is selected for communication according to the status of the communication line.

[0041] Furthermore, the use of a bidirectional communication line for data transmission includes:

[0042] Detect the working status of the two communication lines in a two-way communication line;

[0043] If both communication lines are working properly, one of them will be configured as the transmitting line and the other as the receiving line, and communication will be carried out in full-duplex mode.

[0044] If one of the communication lines fails, the remaining communication lines will be switched to bidirectional half-duplex mode. In half-duplex mode, the MCU controller sends data packets to each level of the battery controller. Each level of the battery controller forwards the data packets and parses and executes them. After receiving the data packets, the last level of the battery controller returns a status data packet, which is then transmitted level by level to finally reach the MCU controller.

[0045] Furthermore, in half-duplex mode, the MCU controller first sends data packets to each level of battery controller, including:

[0046] The MCU controller sends data packets to the first-stage battery controller through the remaining communication lines;

[0047] The first-level battery controller receives and parses the data packet, performs the corresponding control operation, and then forwards the data packet to the second-level battery controller.

[0048] Each level of the battery controller receives, parses, executes, and forwards the data packets sequentially until the last level of the battery controller completes the processing;

[0049] After the final stage battery controller finishes processing, it begins to transmit the status data packet in reverse. Each stage battery controller adds its own status information to the status data packet in turn, and transmits it to the MCU controller level by level.

[0050] Furthermore, the frame format of the configured data packet is a long command frame, a long status frame, a short command frame, or a short status frame. Based on the transmission control mechanism of the corresponding frame, the return delay is set to adjust the communication response speed.

[0051] Long command frames are used by the MCU controller to send commands to all battery controllers.

[0052] Long status frames are used by all battery controllers to feed back status information to the MCU controller.

[0053] Short command frames are used by the MCU controller to send priority commands to a specific battery controller.

[0054] Short status frames are used by a specific battery controller to feed back status information to the MCU controller.

[0055] Fifthly, the present invention provides a computer-readable storage medium on which a computer program is stored, wherein the computer program, when executed by a processor, implements the communication method described above.

[0056] The beneficial effects of this invention are:

[0057] This invention discloses a series battery management system that requires only a low-voltage chip and a bidirectional series communication link with a non-isolated communication interface in terms of hardware. The low-voltage chip and non-isolated communication greatly simplify the complexity of chip design, and the bidirectional series communication link reduces the need for circuit board wiring resources, improves communication reliability, and provides redundancy backup.

[0058] This invention discloses a method for managing series-connected battery packs. A control unit is connected in series with multiple battery controllers to manage each battery cell. The battery controllers employ a non-isolated communication interface and include switches A, B, C, and D, digital logic circuitry, and level converters. This enables battery access bypass and power supply switching. The level converters switch based on the potential difference between adjacent stages, ensuring normal communication between controllers at different levels. The communication link uses a dual-line backup design, supporting full-duplex and half-duplex modes. This invention solves the problem of managing batteries at different levels in series-connected battery packs, achieving flexible battery access bypass control, reliable communication transmission, and power supply switching in case of failure, thus improving system reliability and communication efficiency.

[0059] This invention discloses a communication method for a series battery management system. Using a standard communication protocol, it supports the application of general BMS chips, allowing chips from different manufacturers to use a unified interface. This enables MCU software development to be mutually compatible, facilitating the industrialization and standardization of BMS products. This invention solves key problems in series battery packs, such as abnormal battery handling, cross-voltage domain communication, and real-time management, improving the efficiency and safety of the battery pack.

[0060] Other features and advantages of the present invention will be described in detail in the following detailed description section. The purpose of this invention is to address the problem of effective management and reliable communication of large-scale series-connected batteries by proposing a series-connected battery management system, management method, and communication method. In this invention, all chips operate in a low-voltage power domain, all interfaces are non-isolated interfaces, and the controller MCU acts as the master controller managing all battery pack controllers. Due to the all-low-voltage characteristics, the system has a fast response speed and is not limited by the number of series-connected battery packs, exhibiting good scalability. It can effectively manage large-scale series-connected battery packs and is suitable for battery management in fields such as electric vehicles and energy storage.

[0061] The technical solution of this invention is:

[0062] In a first aspect, the present invention provides a series battery management system, including an MCU controller and a battery controller configured for each battery in the series battery. Each battery controller is connected in series via a communication link and communicates with the MCU controller. The battery controller closest to the MCU controller is set as the first level, and the battery controller furthest from the MCU controller is set as the Nth level. The MCU controller and each battery controller operate in a low-voltage power domain and use a non-isolated interface for data transmission.

[0063] The battery controller includes switch A, switch B, switch C, switch D, digital logic circuitry, and level converter.

[0064] Switch A is connected in series with the battery to form a branch, and switch B is connected in parallel with the series branch formed by switch A and the battery. Switches A and B are used to control whether the battery is connected.

[0065] One end of switch C is connected to the connection point between switch A and the battery. The other end of switch C is connected to the power supply terminal of the digital logic circuit on one side and to the connection point between switch D and switch D in the adjacent lower-level battery controller on the other side. The switches D of the adjacent battery controllers are connected in series. The switches C and D are used to control the power supply mode and communication level setting of the digital logic circuit.

[0066] The digital logic circuit is connected to the level converter via a bidirectional communication link. The power supply terminal of the level converter is connected to both ends of switch D. The level converters of adjacent battery controllers are connected in series via a bidirectional communication link.

[0067] The MCU controller is used to collect the power information of each battery, determine the working mode of the corresponding battery based on the power information, adjust the switch state in the battery controller, realize battery access switching, and ensure the power supply of the level converter and digital logic circuit.

[0068] Furthermore, an adaptive communication level conversion based on the potential difference between adjacent battery controllers is achieved through a level converter. The two ends of the level converter are high and low levels, respectively. When the battery is normally connected, the high and low levels differ by one battery voltage. When the battery is bypassed, the voltages at both ends of the level converter are the same, thus realizing communication between different levels of battery controllers.

[0069] Secondly, the present invention provides a management method for a series battery management system, wherein each battery in the series battery is configured with a corresponding battery controller, and each battery controller is connected in series via a communication link and communicates with an MCU controller; both the MCU controller and the battery controller operate in the low-voltage power domain and use a non-isolated interface for data transmission; the management method includes:

[0070] The MCU controller obtains the power information of each cell in the series battery through the serial communication link, and determines the working mode of the corresponding cell based on the power information.

[0071] Adjust the switch state in the battery controller according to the battery's operating mode to achieve battery access switching and ensure power supply to the level converter and digital logic circuit.

[0072] Meanwhile, adaptive level conversion is performed by a level converter based on the potential difference between adjacent battery controllers. The two ends of the level converter are high and low levels, respectively. When the battery is normally connected, the high and low levels differ by one battery voltage. When the battery is bypassed, the voltages at both ends of the level converter are the same, realizing communication between different levels of battery controllers.

[0073] Furthermore, adjusting the switch state in the battery controller according to the battery's operating mode to achieve battery access switching and ensure power supply to the level converter and digital logic circuit includes:

[0074] Detect battery power information;

[0075] If in normal working mode, select switch A and switch C to connect the battery. The high level of this battery is connected to the digital logic circuit and the low level of the level converter through the switches A and C. The high level of the level converter is powered by the upstream battery, ensuring that the level converter and digital logic circuit work normally.

[0076] If in an abnormal operating mode, select switch B and switch D to bypass the battery. Then, connect the power supply of the upstream battery to the digital logic circuit and the high and low levels of the level converter through switches B and D to ensure that the level converter and digital logic circuit work normally.

[0077] Furthermore, adaptive level conversion based on the potential difference between adjacent battery controllers via a level converter includes:

[0078] Obtain the low level VB_n and high level VC_n of the nth battery, 1≤n≤N, and calculate the voltage V0 of a single battery cell.

[0079] When the battery is connected;

[0080] The supply voltage of the nth level digital logic circuit is equal to the low level of the nth level battery plus the voltage of a single battery cell, i.e., VDD_n = VC_n = VB_n + V0;

[0081] The low level of communication in the nth level digital logic circuit is equal to the low level of the nth level battery plus the single-cell battery voltage VL_n = VB_n + V0; the high level of communication is equal to the low level of the nth level battery plus twice the single-cell battery voltage VH_n = VB_n + 2*V0.

[0082] When the battery is bypassed;

[0083] The nth level digital circuit is powered by the (n+1)th level, i.e., VDD_(n) = VL_n+1 = VB_n+1 + V0 = VB_n + V0;

[0084] The communication low level and the communication high level are both equal to the low level of the nth battery plus the single cell voltage VL_n = VH_n = VB_n + V0;

[0085] Based on the potential difference of the communication level, a level converter is used to shift the signal level up, down, or horizontally to achieve normal communication with the adjacent battery controller.

[0086] Furthermore, the step of using a level converter to shift the signal level up, down, or horizontally based on the potential difference of the communication level includes:

[0087] When the battery is connected, the level converter shifts the digital signal level output by the nth stage up by one cell battery voltage to match the communication level of the (n+1)th stage; or the level converter shifts the digital signal level output by the (n+1)th stage down by one cell battery voltage to match the communication level of the nth stage.

[0088] When the battery is bypassed, the level converter shifts and converts the digital signal level output by the nth stage to maintain the same communication level as the (n+1)th stage.

[0089] Thirdly, the present invention provides a computer-readable storage medium on which a computer program is stored, and which, when executed by a processor, implements the management method described above.

[0090] Fourthly, the present invention provides a communication method for the series battery management system, wherein the communication link uses a bidirectional communication line for data transmission, the bidirectional communication lines serve as backups for each other, and full-duplex mode or half-duplex mode is selected for communication according to the status of the communication line.

[0091] Furthermore, the use of a bidirectional communication line for data transmission includes:

[0092] Detect the working status of the two communication lines in a two-way communication line;

[0093] If both communication lines are working properly, one of them will be configured as the transmitting line and the other as the receiving line, and communication will be carried out in full-duplex mode.

[0094] If one of the communication lines fails, the remaining communication lines will be switched to bidirectional half-duplex mode. In half-duplex mode, the MCU controller sends data packets to each level of the battery controller. Each level of the battery controller forwards the data packets and parses and executes them. After receiving the data packets, the last level of the battery controller returns a status data packet, which is then transmitted level by level to finally reach the MCU controller.

[0095] Furthermore, in half-duplex mode, the MCU controller first sends data packets to each level of battery controller, including:

[0096] The MCU controller sends data packets to the first-stage battery controller through the remaining communication lines;

[0097] The first-level battery controller receives and parses the data packet, performs the corresponding control operation, and then forwards the data packet to the second-level battery controller.

[0098] Each level of the battery controller receives, parses, executes, and forwards the data packets sequentially until the last level of the battery controller completes the processing;

[0099] After the final stage battery controller finishes processing, it begins to transmit the status data packet in reverse. Each stage battery controller adds its own status information to the status data packet in turn, and transmits it to the MCU controller level by level.

[0100] Furthermore, the frame format of the configured data packet is a long command frame, a long status frame, a short command frame, or a short status frame. Based on the transmission control mechanism of the corresponding frame, the return delay is set to adjust the communication response speed.

[0101] Long command frames are used by the MCU controller to send commands to all battery controllers.

[0102] Long status frames are used by all battery controllers to feed back status information to the MCU controller.

[0103] Short command frames are used by the MCU controller to send priority commands to a specific battery controller.

[0104] Short status frames are used by a specific battery controller to feed back status information to the MCU controller.

[0105] Fifthly, the present invention provides a computer-readable storage medium on which a computer program is stored, wherein the computer program, when executed by a processor, implements the communication method described above.

[0106] The beneficial effects of this invention are:

[0107] This invention discloses a series battery management system that requires only a low-voltage chip and a bidirectional series communication link with a non-isolated communication interface in terms of hardware. The low-voltage chip and non-isolated communication greatly simplify the complexity of chip design, and the bidirectional series communication link reduces the need for circuit board wiring resources, improves communication reliability, and provides redundancy backup.

[0108] This invention discloses a method for managing series-connected battery packs. A control unit is connected in series with multiple battery controllers to manage each battery cell. The battery controllers employ a non-isolated communication interface and include switches A, B, C, and D, digital logic circuitry, and level converters. This enables battery access bypass and power supply switching. The level converters switch based on the potential difference between adjacent stages, ensuring normal communication between controllers at different levels. The communication link uses a dual-line backup design, supporting full-duplex and half-duplex modes. This invention solves the problem of managing batteries at different levels in series-connected battery packs, achieving flexible battery access bypass control, reliable communication transmission, and power supply switching in case of failure, thus improving system reliability and communication efficiency.

[0109] This invention discloses a communication method for a series battery management system. Using a standard communication protocol, it supports the application of general BMS chips, allowing chips from different manufacturers to use a unified interface. This enables MCU software development to be mutually compatible, facilitating the industrialization and standardization of BMS products. This invention solves key problems in series battery packs, such as abnormal battery handling, cross-voltage domain communication, and real-time management, improving the efficiency and safety of the battery pack.

[0110] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0111] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0112] Figure 1 A comparative schematic diagram of the conventional all-series battery pack architecture and the new system battery pack bypass architecture is shown in the background art.

[0113] Figure 2 A schematic diagram of a series battery management system according to an embodiment of the present invention is shown.

[0114] Figure 3 A schematic diagram of battery access, level shifter, and power supply to digital logic circuitry is shown when the battery is in normal operating mode according to an embodiment of the present invention.

[0115] Figure 4 A schematic diagram is shown below, illustrating the level shift of a level converter when the battery is connected in normal operating mode according to an embodiment of the present invention, with the high and low levels of the level converter differing by one battery voltage.

[0116] Figure 5 A schematic diagram is shown below, illustrating the level shift of a level converter when the battery is connected in normal operating mode according to an embodiment of the present invention, with the high and low levels of the level converter differing by one battery voltage.

[0117] Figure 6 A schematic diagram of battery bypass, level converter, and digital logic circuitry power supply is shown when the battery is in an abnormal operating mode according to an embodiment of the present invention.

[0118] Figure 7 One of the schematic diagrams shown is illustrated when the battery is connected in an abnormal operating mode according to an embodiment of the present invention, and the high and low levels of the level converter are the same, and the level is shifted.

[0119] Figure 8 The second schematic diagram shows a level shifting operation performed when the battery is connected in an abnormal operating mode according to an embodiment of the present invention, with the high and low levels of the level converter being the same.

[0120] Figure 9 A schematic diagram is shown when both bidirectional communication links of a series battery management system according to an embodiment of the present invention are working normally.

[0121] Figure 10 The diagram illustrates a bidirectional communication link in a series battery management system according to an embodiment of the present invention, where one communication line fails and the remaining communication lines switch to bidirectional half-duplex mode. Detailed Implementation

[0122] Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0123] Example 1

[0124] Figure 2 A schematic diagram of a series battery management system according to an embodiment of the present invention is shown.

[0125] This invention provides a series battery management system, including an MCU controller and a battery controller configured for each battery in the series battery. Each battery controller is connected in series via a communication link and communicates with the MCU controller. The battery controller closest to the MCU controller is set as the first level, and the battery controller furthest from the MCU controller is set as the (n+1)th level. The MCU controller and each battery controller operate in a low-voltage power domain and use a non-isolated interface for data transmission.

[0126] The battery controller includes switch A, switch B, switch C, switch D, digital logic circuitry, and level converter.

[0127] Switch A is connected in series with the battery to form a branch, and switch B is connected in parallel with the series branch formed by switch A and the battery. Switches A and B are used to control whether the battery is connected.

[0128] One end of switch C is connected to the connection point between switch A and the battery. The other end of switch C is connected to the power supply terminal of the digital logic circuit on one side and to the connection point between switch D and switch D in the adjacent lower-level battery controller on the other side. The switches D of the adjacent battery controllers are connected in series. The switches C and D are used to control the power supply mode and communication level setting of the digital logic circuit.

[0129] The digital logic circuit is connected to the level converter via a bidirectional communication link. The power supply terminal of the level converter is connected to both ends of switch D. The level converters of adjacent battery controllers are connected in series via a bidirectional communication link.

[0130] The MCU controller is used to collect the power information of each battery, determine the working mode of the corresponding battery based on the power information, adjust the switch state in the battery controller, realize battery access switching, and ensure the power supply of the level converter and digital logic circuit.

[0131] Furthermore, an adaptive communication level conversion based on the potential difference between adjacent battery controllers is achieved through a level converter. The two ends of the level converter are high and low levels, respectively. When the battery is normally connected, the high and low levels differ by one battery voltage. When the battery is bypassed, the voltages at both ends of the level converter are the same, thus realizing communication between different levels of battery controllers.

[0132] In this embodiment, as Figure 2 As shown, each battery is defined as a level, starting with the MCU as the first level, followed by the second level, the third level, and so on.

[0133] VB_n represents the low voltage level of the nth battery level, and VC_n represents the high voltage level of the nth battery level. The difference between the high and low voltage levels is V0. Different types of batteries have different V0 values; a typical lithium-ion battery has V0 = 3.7V.

[0134] When the current battery is functioning correctly, VC_n supplies power to the current digital circuit; when the current battery is faulty, the upstream VC_n+1 supplies power to the current digital circuit. In both cases, the voltage difference between the positive and negative terminals of the digital circuit is V0.

[0135] VL_n represents the low level for communication at the nth stage, and VH_n represents the high level for communication at the nth stage. Both power the level converter, shifting the voltage difference signal at the output V0 of this stage up or down by one V0, enabling communication with adjacent stages.

[0136] The MCU operates in the low-voltage domain, with a positive and negative voltage difference of V0. The MCU communicates directly with the first stage and with other stages through communication links; the MCU and the battery controller follow a unified communication protocol.

[0137] Example 2

[0138] Figure 3 A schematic diagram of battery access, level shifter, and power supply to digital logic circuitry is shown when the battery is in normal operating mode according to an embodiment of the present invention.

[0139] Figure 6 A schematic diagram of battery bypass, level converter, and digital logic circuitry power supply is shown when the battery is in an abnormal operating mode according to an embodiment of the present invention.

[0140] This invention provides a management method for a series battery management system, wherein each battery in the series battery is configured with a corresponding battery controller, and the battery controllers are connected in series via a communication link and communicate with an MCU controller; both the MCU controller and the battery controller operate in a low-voltage power domain and use a non-isolated interface for data transmission; the management method includes:

[0141] The MCU controller obtains the power information of each cell in the series battery through the serial communication link, and determines the working mode of the corresponding cell based on the power information.

[0142] Adjust the switch state in the battery controller according to the battery's operating mode to achieve battery access switching and ensure power supply to the level converter and digital logic circuit.

[0143] Meanwhile, adaptive level conversion is performed by a level converter based on the potential difference between adjacent battery controllers. The two ends of the level converter are high and low levels, respectively. When the battery is normally connected, the high and low levels differ by one battery voltage. When the battery is bypassed, the voltages at both ends of the level converter are the same, realizing communication between different levels of battery controllers.

[0144] Specifically, adjusting the switch state in the battery controller according to the battery's operating mode to achieve battery access switching and ensure power supply to the level converter and digital logic circuit includes:

[0145] Detect battery power information;

[0146] If in normal working mode, select switch A and switch C to connect the battery. The high level of this battery is connected to the digital logic circuit and the low level of the level converter through the switches A and C. The high level of the level converter is powered by the upstream battery, ensuring that the level converter and digital logic circuit work normally.

[0147] If in an abnormal operating mode, select switch B and switch D to bypass the battery. Then, connect the power supply of the upstream battery to the digital logic circuit and the high and low levels of the level converter through switches B and D to ensure that the level converter and digital logic circuit work normally.

[0148] In this embodiment, switches A and C are activated when each battery is functioning normally. The power supply relationship between stage n and stage n+1 is as follows: Figure 3 Black highlight.

[0149] The power supply for the nth-level digital circuit is VDD_n = VC_n = VB_n + V0;

[0150] The high level of the nth level digital signal = VDD_n = VB_n + V0;

[0151] The low level of the nth level digital signal = VB_n;

[0152] The (n+1)th level digital circuit has the following structure: VDD_n+1 = VB_n+1 + V0 = VB_n + 2*V0;

[0153] The high level of the (n+1)th level digital signal = VDD_n+1 = VB_n + 2*V0;

[0154] The low level of the (n+1)th level digital signal = VB_n+1 = VB_n + V0;

[0155] It can be seen that the digital signal level of the (n+1)th level is V0 higher than that of the nth level. Therefore, the signal transmission from the nth level to the (n+1)th level needs to be shifted up by V0 through a level converter circuit.

[0156] The level shifter is powered by VH_n / VL_n:

[0157] VL_n = VB_n + V0;

[0158] VH_n = VB_n + 2 * V0;

[0159] The communication level relationship between level n and level n+1 is as follows: Figure 4 , 5 As shown, Figure 4 This diagram illustrates how, when the battery is in normal operating mode and connected, the high and low levels of the level converter are shifted upwards by the difference of one battery voltage. Figure 5 This diagram illustrates how, when the battery is in normal operating mode and connected, the high and low levels of the level converter are different by one battery voltage, resulting in a level shift.

[0160] In this embodiment, it is assumed that the nth battery is bypassed by switch B due to a fault, at which point switches B and D are activated. The power supply relationship between the nth and (n+1)th stages is as follows: Figure 6 Black highlight.

[0161] The power supply for the nth stage digital circuit is VDD_n = VB_n + V0 (at this time, the battery in this stage fails, and the power supply is transferred from the (n+1)th stage through the closing of switch D, so VDD_(n) = VL_n+1 = VB_n+1 + V0. At the same time, since switch B bypasses the nth battery, VB_(n) = VB_(n+1), so VDD(n) = VB(n) + V0).

[0162] The high level of the nth level digital signal = VDD_n = VB_n + V0;

[0163] The low level of the nth level digital signal = VB_n;

[0164] The (n+1)th level digital circuit is defined as follows: VDD_n+1 = VB_n+1 + V0 = VB_n + V0;

[0165] The high level of the (n+1)th level digital signal = VDD_n+1 = VB_n + V0;

[0166] The low level of the (n+1)th level digital signal = VB_n+1 = VB_n;

[0167] It can be seen that the digital signal level of level n+1 is the same as that of level n. At this point, the level shifter circuit will shift the level. The level shifter is powered by VH_n / VL_n.

[0168] VL_n = VH_n = VB_n + V0;

[0169] The communication level relationship between level n and level n+1 is as follows: Figure 7, 8 The diagrams shown are one and two, illustrating how the high and low levels of the level converter are the same when the battery is connected in an abnormal operating mode, and how the level is shifted.

[0170] Example 3

[0171] The present invention provides a computer-readable storage medium on which a computer program is stored, and the computer program, when executed by a processor, implements the management method described above.

[0172] Example 4

[0173] This invention provides a communication method for a series battery management system, wherein the communication link uses a bidirectional communication line for data transmission, the bidirectional communication lines serve as backups for each other, and the communication is performed in full-duplex or half-duplex mode depending on the status of the communication line.

[0174] Furthermore, the data transmission using a bidirectional communication line includes: detecting the operating status of the two communication lines in the bidirectional communication line; if both communication lines are working normally, one is configured as the transmitting line and the other as the receiving line, and communication is performed in full-duplex mode; if one of the communication lines fails, the remaining communication lines are switched to bidirectional half-duplex mode; in half-duplex mode, the MCU controller sends data packets to each level of the battery controller; each level of the battery controller forwards the data packets and parses and executes them; after receiving the data packets, the last level of the battery controller returns a status data packet, which is then transmitted level by level to finally reach the MCU controller.

[0175] Furthermore, in half-duplex mode, the MCU controller first sends data packets to each level of battery controller, including: the MCU controller sending data packets to the first-level battery controller through the remaining communication lines; the first-level battery controller receiving and parsing the data packets, executing corresponding control operations, and then forwarding the data packets to the second-level battery controller; each level of battery controller sequentially receiving, parsing, executing, and forwarding the data packets until the last level of battery controller completes processing; after the last level of battery controller completes processing, it begins to transmit status data packets in reverse, with each level of battery controller sequentially adding its own status information to the status data packets and transmitting them to the MCU controller level by level.

[0176] Furthermore, the frame format of the configuration data packet is configured as a long command frame, a long status frame, a short command frame, or a short status frame. According to the transmission control mechanism of the corresponding frame, the return delay is set to adjust the communication response speed. Specifically, the long command frame is used for the MCU controller to send commands to all battery controllers; the long status frame is used for all battery controllers to feed back status information to the MCU controller; the short command frame is used for the MCU controller to send priority commands to a specific battery controller; and the short status frame is used for a specific battery controller to feed back status information to the MCU controller.

[0177] In this embodiment, the serial communication system consists of two data lines, each supporting bidirectional communication. The two data lines serve as backups for each other.

[0178] When both data lines are functioning normally, the system is configured in TX / RX mode, where data transmission from the MCU to the battery controller is TX, and vice versa is RX. The TX and RX signal lines can operate independently, improving data transmission efficiency.

[0179] When one data line fails, the remaining data line will be configured in TRX mode, in which case data is transmitted in a bidirectional half-duplex mode. That is, the MCU first sends data packets to the battery controller, which then forwards, parses, and executes the data packets at each level. When the last level receives the data packet, it sends a status data packet back, and after this relay, the packet finally reaches the MCU, completing one full communication cycle.

[0180] TX / RX mode link topology as follows Figure 9 , 10 As shown, Figure 9 The bidirectional communication link of the series battery management system is working normally and is in TX / RX mode; Figure 10 When one of the communication lines in the bidirectional communication link of the series battery management system fails, the remaining communication lines switch to bidirectional half-duplex mode, which is in TRX mode.

[0181] The communication protocol is used for control and data interaction between the MCU and the battery controller. The entire communication protocol is divided into the physical layer, the data link layer and the application layer.

[0182] The communication physical layer adopts TX / RX dual-line communication, with each line supporting bidirectional transmission; the data link layer defines the frame format for communication; and the application layer defines specific battery management protocol data formats and acquisition methods according to different battery pack architectures and application scenarios.

[0183] Specifically, the physical layer uses two signal lines, TX and RX. By default, Tx is used to transmit data from the MCU to the battery string, and RX is used to receive data from the battery string to the MCU. When one of the signal lines fails, the remaining one can be configured for bidirectional half-duplex transmission.

[0184] Because the entire communication link is powered by the battery pack, and the supply voltages of different battery pack nodes differ by a level (V0), different stages of the circuit cannot communicate directly. A level shifter is needed to transmit logic signals between different voltage domains. In normal communication mode, the voltage difference between the (n-1)th and nth batteries is V0. Therefore, the TX signal of the (n-1)th battery needs to be shifted up by V0 to communicate with the nth battery. Conversely, the RX signal of the nth battery needs to be shifted down by V0 to communicate with the (n-1)th battery.

[0185] When the nth battery fails, the A / B switch is used to switch over. Figure 10 In the case where the nth battery is bypassed, VL_n remains equal to (n-1)*V0, and VH_n is powered by VH_n+1, with a voltage level of n*V0. For the (n+1)th battery, VL_n+1 = (n-1)*V0 (because one battery is bypassed, the entire battery pack voltage drops by V0), and the high voltage level VH_n+1 = n*V0. This means that the nth and (n+1)th batteries, being in the same power domain, can communicate directly (at this time, the level shifter circuit is still working, but since there is no voltage difference between the input and output voltage domains, the level shifter is equivalent to shifting the signal). In the event of multiple battery failures, the voltage of the entire battery pack will drop as the failed battery is switched out. However, the remaining batteries can still communicate. The communication level will adaptively shift with each battery switch.

[0186] Physical layer communication transmits data bit by bit according to the baud rate.

[0187] Physical layer address: Each battery in the resistor string needs a physical address, numbered 1 / 2 / ... / N according to its distance from the MCU. Address 0 is reserved as the broadcast address.

[0188] The physical layer supports both static and dynamic address resolution protocols.

[0189] When using static addresses, chip pins or fuse static addressing can be used.

[0190] If the controller does not have extra pins or fuses for static addressing, a dynamic addressing protocol can be used to automatically initialize each controller. The system completes the addressing of each controller chip by initializing the address bootstrap protocol.

[0191] Specifically, the data link layer defines the frame format. Each battery is allocated a 64-bit payload packet, and then the information for that battery is loaded into it. Information is loaded cell by cell. Chained communication is used, which is easy to expand.

[0192] Data frames can be divided into command frames and status frames. Each type of frame is further divided into long and short modes, resulting in a total of four frame formats, as shown in Table 1.

[0193] Table 1

[0194]

[0195] The specific frame format is shown in Table 2;

[0196] Table 2

[0197]

[0198] Header: Fixed at 0x7e; P1~PN: Payload for N batteries.

[0199] Long and short command frames are shown in Tables 3 and 4;

[0200] Table 3

[0201]

[0202] Table 4

[0203]

[0204] Transmission Control: To challenge and control the link response speed, a response time (delay) can be set in the command frame. This is the time the system needs to wait after the command is sent to the last node. For example, in a battery measurement command, due to the relatively fast communication transmission speed, when the last node receives the command, most battery measurements may not have finished. Therefore, it needs to wait for a period of time. Once all nodes have completed their measurements, the last node starts sending back status data packets via RX.

[0205] Transmission control is achieved through the return delay in the aforementioned control register.

[0206] Error control: This protocol defines a timeout mechanism. When the MCU does not receive a communication response from the battery within a specified time, it will trigger a retransmission mechanism or a system reset mechanism.

[0207] Specifically, the application layer includes the protocol layer, which defines the information (voltage, current, etc.) that needs to be collected for each battery cell. This information is packaged in the payload of the data link layer. The content can be specifically defined depending on the BMS system application. Each payload packet is 8 bytes in size, where the first byte is the local address, the next six bytes are the application layer data, and the last byte is the CRC8 checksum of the data. During TX transmission, P1~PN are command frames; during RX transmission, P1~PN are status frames.

[0208] The application layer can be defined by the user. For example, for a small BMS system for lithium batteries, 6 bytes of user information can be defined as follows:

[0209] Command frames configure the controller parameters and operating modes for each battery cell, trigger measurements, manage batteries, etc., as shown in Table 5; status frames, when the load pack is used as a status, are defined as shown in Table 6.

[0210] Table 5

[0211]

[0212] Table 6

[0213]

[0214] Example 5

[0215] The present invention provides a computer-readable storage medium on which a computer program is stored, and the computer program, when executed by a processor, implements the communication method described above.

[0216] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A series battery management system, characterized in that, The system includes an MCU controller and a battery controller configured for each battery cell in the series-connected battery. Each battery controller is connected in series via a communication link and communicates with the MCU controller. The battery controller closest to the MCU controller is designated as the first level, and the battery controller furthest from the MCU controller is designated as the Nth level. Both the MCU controller and each battery controller operate in the low-voltage power domain and use a non-isolated interface for data transmission. The battery controller includes switch A, switch B, switch C, switch D, digital logic circuitry, and level converter. Switch A is connected in series with the battery to form a branch, and switch B is connected in parallel with the series branch formed by switch A and the battery. Switches A and B are used to control whether the battery is connected. One end of switch C is connected to the connection point between switch A and the battery. The other end of switch C is connected to the power supply terminal of the digital logic circuit on one side and to the connection point between switch D and switch D in the adjacent lower-level battery controller on the other side. The switches D of the adjacent battery controllers are connected in series. The switches C and D are used to control the power supply mode and communication level setting of the digital logic circuit. The digital logic circuit is connected to the level converter via a bidirectional communication link. The power supply terminal of the level converter is connected to both ends of switch D. The level converters of adjacent battery controllers are connected in series via a bidirectional communication link. The MCU controller is used to collect the power information of each battery, determine the working mode of the corresponding battery based on the power information, adjust the switch state in the battery controller, realize battery access switching, and ensure the power supply of the level converter and digital logic circuit. Furthermore, an adaptive communication level conversion for the potential difference between adjacent battery controllers is achieved through a level converter; The level converter has a high level and a low level at its two ends. When the battery is connected normally, the high and low levels differ by one battery voltage. When the battery is bypassed, the voltages at both ends of the level converter are the same, enabling communication between different levels of battery controllers.

2. A management method employed in the series battery management system of claim 1, characterized in that... Each battery in the series-connected battery is configured with a corresponding battery controller. The battery controllers are connected in series via a communication link and communicate with the MCU controller. Both the MCU controller and the battery controller operate in the low-voltage power domain and use a non-isolated interface for data transmission. The management method includes: The MCU controller obtains the power information of each cell in the series battery through the serial communication link, and determines the working mode of the corresponding cell based on the power information. Adjust the switch state in the battery controller according to the battery's operating mode to achieve battery access switching and ensure power supply to the level converter and digital logic circuit. Meanwhile, adaptive level conversion is performed by a level converter based on the potential difference between adjacent battery controllers. The two ends of the level converter are high and low levels, respectively. When the battery is normally connected, the high and low levels differ by one battery voltage. When the battery is bypassed, the voltages at both ends of the level converter are the same, realizing communication between different levels of battery controllers.

3. The management method as described in claim 2, characterized in that, The step of adjusting the switch state in the battery controller according to the battery's operating mode to achieve battery access switching and ensure power supply to the level converter and digital logic circuit includes: Detect battery power information; If in normal working mode, select switch A and switch C to connect the battery. The high level of this battery is connected to the digital logic circuit and the low level of the level converter through the switches A and C. The high level of the level converter is powered by the upstream battery, ensuring that the level converter and digital logic circuit work normally. If in an abnormal operating mode, select switch B and switch D to bypass the battery. Then, connect the power supply of the upstream battery to the digital logic circuit and the high and low levels of the level converter through switches B and D to ensure that the level converter and digital logic circuit work normally.

4. The management method as described in claim 2, characterized in that... Adaptive level conversion based on the potential difference between adjacent battery controllers includes: Obtain the low level VB_n and high level VC_n of the nth battery, 1≤n≤N, and calculate the voltage V0 of a single battery cell. When the battery is connected; The supply voltage of the nth level digital logic circuit is equal to the low level of the nth level battery plus the voltage of a single battery cell, i.e., VDD_n = VC_n = VB_n + V0; The low level of communication in the nth level digital logic circuit is equal to the low level of the nth level battery plus the single-cell battery voltage VL_n = VB_n + V0; the high level of communication is equal to the low level of the nth level battery plus twice the single-cell battery voltage VH_n = VB_n + 2*V0. When the battery is bypassed; The nth level digital circuit is powered by the (n+1)th level, i.e., VDD_(n) = VL_n+1 = VB_n+1 + V0 = VB_n + V0; The communication low level and the communication high level are both equal to the low level of the nth battery plus the voltage of a single cell, VL_n = VH_n = VB_n + V0; Based on the potential difference of the communication level, a level converter is used to shift the signal level up, down, or horizontally to achieve normal communication with the adjacent battery controller.

5. The management method as described in claim 4, characterized in that... The step of using a level converter to shift the signal level up, down, or horizontally based on the potential difference of the communication level includes: When the battery is connected, the level converter shifts the digital signal level output by the nth stage up by one cell battery voltage to match the communication level of the (n+1)th stage; or the level converter shifts the digital signal level output by the (n+1)th stage down by one cell battery voltage to match the communication level of the nth stage. When the battery is bypassed, the level converter shifts and converts the digital signal level output by the nth stage to maintain the same communication level as the (n+1)th stage.

6. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, which, when executed by a processor, implements the management method as described in any one of claims 2 to 5.

7. A communication method used in the series battery management system of claim 1, characterized in that... The communication link uses a bidirectional communication line for data transmission, and the bidirectional communication lines serve as backups for each other. The communication is conducted in either full-duplex or half-duplex mode depending on the status of the communication line.

8. The communication method as described in claim 7, characterized in that... The use of bidirectional communication lines for data transmission includes: Detect the working status of the two communication lines in a two-way communication line; If both communication lines are working properly, one of them will be configured as the transmitting line and the other as the receiving line, and communication will be carried out in full-duplex mode. If one of the communication lines fails, the remaining communication lines will be switched to bidirectional half-duplex mode. In half-duplex mode, the MCU controller sends data packets to each level of the battery controller. Each level of the battery controller forwards the data packets and parses and executes them. After receiving the data packets, the last level of the battery controller returns a status data packet, which is then transmitted level by level to finally reach the MCU controller.

9. The communication method as described in claim 8, characterized in that... In half-duplex mode, the MCU controller first sends data packets to each level of the battery controller, including: The MCU controller sends data packets to the first-stage battery controller through the remaining communication lines; The first-level battery controller receives and parses the data packet, performs the corresponding control operation, and then forwards the data packet to the second-level battery controller. Each level of the battery controller receives, parses, executes, and forwards the data packets sequentially until the last level of the battery controller completes the processing; After the final stage battery controller finishes processing, it begins to transmit the status data packet in reverse. Each stage battery controller adds its own status information to the status data packet in turn, and transmits it to the MCU controller level by level.

10. The communication method as described in claim 8, characterized in that, Configure the data packet frame format as a long command frame, a long status frame, a short command frame, or a short status frame. Based on the transmission control mechanism of the corresponding frame, set the return delay to adjust the communication response speed. Long command frames are used by the MCU controller to send commands to all battery controllers. Long status frames are used by all battery controllers to feed back status information to the MCU controller. Short command frames are used by the MCU controller to send priority commands to a specific battery controller. Short status frames are used by a specific battery controller to feed back status information to the MCU controller.

11. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, which, when executed by a processor, implements the communication method as described in any one of claims 7 to 10.

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