Series battery management system, management method, communication method and medium

Abstract

The invention provides a series battery management system, a management method, a communication method and a medium, the system correspondingly configures a battery controller for each battery in series batteries, and the battery controllers are connected in series through communication links and communicate with an MCU controller; the MCU controller and the battery controller both work in a low-voltage power supply domain, a non-isolated interface is adopted for data transmission, and the method comprises the following steps: acquiring electric quantity information of each battery, and determining a working mode of the corresponding battery; the switch state in the battery controller is adjusted to realize battery access switching, and power supply of the level converter and the digital logic circuit is ensured; meanwhile, self-adaptive level conversion is carried out through a level converter according to the potential difference between the adjacent levels of battery controllers. All chips in the system work in a low-voltage power supply domain, the response speed of the system is high, the system is not limited by the number of series battery packs, and the system has good expansibility and is suitable for battery management in the fields of electric automobiles, energy storage and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power management, and more particularly, to a series battery management system, a management method, a communication method and a medium. BACKGROUND

[0002] In electronic devices or battery energy storage devices, as the total capacity of the battery increases, a series battery pack system is often used without changing the system rated current, but due to the inconsistency of the series battery, the effective total capacity of the battery will decrease, so the common mode patent "a battery management system and method" and "a chip management system for a series structure of multiple batteries" proposes to use a group of switches to realize the function of bypassing the battery, which not only solves the problem of the decrease of the effective capacity of the series battery pack caused by the performance decrease of the single battery, but also avoids the failure of the entire series battery pack caused by the failure of the single battery, in addition, the switch switching mode can achieve the effect of fast charging and deep discharging of the entire series battery pack In the management of multiple series battery packs, a high-voltage battery management analog front-end chip is often used to measure the battery pack and transmit the measurement value of the battery to the control chip of the system. Figure 1 The current communication method has the following disadvantages: 1. In this high-voltage architecture, it is often limited by the voltage resistance of the high-voltage battery management analog front-end chip. For example, for an analog front-end chip with a voltage resistance of 80V, if the maximum voltage of the battery is 4.3V, then a voltage-resistant chip can measure at most 18 battery packs. When the number of series battery packs exceeds 18, additional chips are needed for measurement. 2. When the number of series battery packs continues to increase, more high-voltage chips are needed, and the system connection becomes more complex. It is very difficult to lay a large number of high-voltage lines on the board. 3. The BMS generally includes an MCU to complete system monitoring and charge / discharge management. The MCU is in a low-voltage domain and needs to be isolated for different voltage levels when communicating with each battery. Due to the inconsistency of battery characteristics, the voltage range of each battery varies greatly, and the reliable isolation of the communication system is very complex.

[0003] 4. If the connection between the battery and the AFE fails, the battery management will fail.

[0004] 5. The current BMS communication system does not have a standard protocol, and products from different manufacturers are not compatible, which makes the software cannot be used across platforms, wasting a lot of manpower and resources to develop software repeatedly.

[0005] Therefore, how to avoid high-voltage environment, realize effective management and reliable communication of large-scale series batteries, and ensure the safe and reliable operation of the entire system is a problem to be solved. SUMMARY

[0006] The purpose of the present application is to propose a series battery management system, a management method and a communication method for the effective management and reliable communication of large-scale series batteries. All chips in the present application work in a low-voltage power domain, all interfaces are non-isolated interfaces, and the controller MCU serves as the master controller to manage all battery pack controllers. Due to the all-low-voltage characteristics, the system has fast response speed and is not limited by the number of series battery packs, has good scalability, can effectively manage large-scale series battery packs, and is suitable for battery management in the fields of electric vehicles and energy storage.

[0007] The technical solution of the present application is: In a first aspect, the present application provides a series battery management system, which comprises an MCU controller and a battery controller corresponding to each battery in a series battery, each battery controller is connected in series through 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 farthest from the MCU controller is set as the Nth level, the MCU controller and each battery controller work in a low-voltage power domain, and a non-isolated interface is used for data transmission, wherein; The battery controller comprises a switch A, a switch B, a switch C, a switch D, a digital logic circuit and a level converter; The switch A is connected in series with the battery to form a branch, the switch B is connected in parallel with the series branch formed by the switch A and the battery, and the switches A and B are used to control whether the battery is connected; One end of the switch C is connected to the connection point of the switch A and the battery, and the other end of the switch C is connected to the power supply end of the digital logic circuit on one hand and connected to the connection point of the switch D and the adjacent lower-level battery controller on the other hand, the switches D of the adjacent battery controllers are connected in series, and the switches C and D are used to control the power supply mode of the digital logic circuit and the communication level setting; The digital logic circuit is connected to the level converter through a bidirectional communication link, the power supply end of the level converter is connected to both ends of the switch D, and the level converters of the adjacent battery controllers are connected in series through 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 according to the power information of the battery, adjust the switch state in the battery controller, realize the battery connection switching, and ensure the power supply of the level converter and the digital logic circuit; And the level converter completes the adaptive communication level conversion between the adjacent level battery controllers; the two ends of the level converter are respectively high level and low level, when the battery is normally connected, the high level and the low level differ by one battery voltage; when the battery is bypassed, the voltages at both ends of the level converter are the same, realizing the communication between battery controllers of different levels.

[0008] In a second aspect, the application provides a management method for a series battery management system, each battery controller corresponding to each battery in the series battery is configured, each battery controller is connected in series through a communication link and communicates with an MCU controller; the MCU controller and the battery controller both work in a low-voltage power supply domain, data transmission is performed through a non-isolated interface, and the management method comprises the following steps. The MCU controller acquires the power information of each battery in the series battery through the series communication link, and determines the working mode of the corresponding battery according to the power information of the battery; According to the working mode of the battery, the switch state in the battery controller is adjusted to realize battery access switching and ensure the power supply of the level converter and the digital logic circuit; Meanwhile, adaptive level conversion is performed through the level converter according to the potential difference between adjacent battery controllers; the level converter has a high level and a low level at two ends, when the battery is normally accessed, the high level and the low level differ by one battery voltage; when the battery is bypassed, the voltages at the two ends of the level converter are the same, realizing communication between battery controllers of different levels.

[0009] Further, the step of adjusting the switch state in the battery controller according to the working mode of the battery to realize battery access switching and ensure the power supply of the level converter and the digital logic circuit comprises the following steps. The power information of the battery is detected; If the battery is in a normal working mode, switches A and C are enabled, the battery is accessed, the high level of the battery at this level 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 supplied by the battery at the upper level, and the level converter and the digital logic circuit are ensured to work normally; If the battery is in an abnormal working mode, switches B and D are enabled, the battery is bypassed, the power supply of the battery at the upper level is connected to the digital logic circuit and the high and low levels of the level converter through the switches B and D, and the level converter and the digital logic circuit are ensured to work normally.

[0010] Further, the adaptive level conversion through the level converter according to the potential difference between adjacent battery controllers comprises the following steps. The low level VB_n and the high level VC_n of the nth battery are acquired, 1≤n≤N, and the voltage V0 of a single battery is calculated; When the battery is accessed; The power supply voltage of the nth digital logic circuit is equal to the low level of the nth battery plus the voltage of a single battery, that is, VDD_n=VC_n=VB_n+V0; The communication low level of the nth digital logic circuit is equal to the nth battery low level plus a single battery voltage VL_n=VB_n+V0, and the communication high level is equal to the nth battery low level plus twice the single battery voltage VH_n=VB_n+2*V0; When the battery is bypassed; The nth digital circuit is powered by the (n+1)th, i.e., VDD_(n)=VL_n+1=VB_n+1+V0=VB_n+V0; The communication low level and the communication high level are equal to the nth battery low level plus a single battery voltage VL_n=VH_n=VB_n+V0; According to the potential difference of the communication level, a level shifter is used to upshift, downshift or shift the signal level, so as to realize normal communication with the adjacent battery controller.

[0011] Further, the level shifter includes: When the battery is connected, the level shifter upshifts the digital signal level output by the nth by a single battery voltage, so as to match the communication level of the (n+1)th; or the level shifter downshifts the digital signal level output by the (n+1)th by a single battery voltage, so as to match the communication level of the nth; When the battery is bypassed, the level shifter performs shift conversion on the digital signal level output by the nth, so as to keep the same communication level as the (n+1)th.

[0012] In a third aspect, the present application provides a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and the computer program is executed by a processor to implement the management method.

[0013] In a fourth aspect, the present application provides a communication method used by a series battery management system, wherein a bidirectional communication line is used for data transmission, the bidirectional communication line is mutual backup, and a full-duplex mode or a half-duplex mode is selected according to the communication line state for communication.

[0014] Further, the bidirectional communication line includes: Detecting the working state of the two communication lines in the bidirectional communication line; If both the two communication lines are normally working, one of them is configured as a sending line, and the other is configured as a receiving line, and a full-duplex mode is used for communication; If one of the communication lines fails, the remaining communication lines are switched to a bidirectional half-duplex mode; in the half-duplex mode, the MCU controller sends data packets to the battery controllers at each level; the battery controllers at each level forward the data packets step by step and analyze and execute; and the last battery controller returns a status data packet in reverse after receiving the completion, and finally reaches the MCU controller through step-by-step transmission.

[0015] Further, in the half-duplex mode, the MCU controller first sends data packets to the battery controllers at each level, including: The MCU controller sends data packets to the first-level battery controller through the remaining communication lines; The first-level battery controller receives and analyzes the data packets, performs corresponding control operations, and then forwards the data packets to the second-level battery controller; The battery controllers at each level receive, analyze, execute and forward the data packets in turn until the last battery controller completes the processing; After the last battery controller completes the processing, it starts to transmit a status data packet in reverse, and each battery controller at each level adds the status information of the current level to the status data packet and transmits it to the MCU controller step by step.

[0016] Further, the frame format of the configuration data packet is 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, wherein: 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; The short status frame is used for a specific battery controller to feed back status information to the MCU controller.

[0017] In a fifth aspect, the present application provides a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and the computer program is executed by a processor to implement the communication method.

[0018] The present application has the following advantages: The present application discloses a series battery management system, which only needs a low-voltage chip and a bidirectional series communication link of a non-isolated communication interface on the hardware; the low-voltage chip and the non-isolated communication greatly simplify the complexity of chip design, the bidirectional series communication link reduces the demand for wiring resources of a circuit board, improves the communication reliability, and provides redundancy backup at the same time.

[0019] The application discloses a series battery pack management method, and realizes management on each battery through a control unit and a plurality of battery controllers connected in series.

[0020] The application discloses a communication method used in a series battery management system, which can support the application of general BMS chips by using a standard communication protocol, and can make the MCU software development compatible with each other by using a unified interface of chips of different manufacturers, thereby being beneficial to the industrialization and standardization of BMS products.

[0021] The application aims at the effective management and reliable communication of large-scale series batteries, and provides a series battery management system, a management method and a communication method.

[0022] The technical scheme of the application is as follows: In a first aspect, the application provides a series battery management system, which comprises an MCU controller and a battery controller corresponding to each battery in a series battery, the battery controllers are connected in series through a communication link and communicate with the MCU controller, the battery controller closest to the MCU controller is set as a first level, and the battery controller farthest from the MCU controller is set as an Nth level, the MCU controller and the battery controllers all work in a low-voltage power domain, and a non-isolated interface is used for data transmission, wherein The battery controller comprises a switch A, a switch B, a switch C, a switch D, a digital logic circuit and a level converter. The switch A is connected in series with the battery to form a branch, the switch B is connected in parallel with the series branch formed by the switch A and the battery, and the switches A and B are used for controlling whether the battery is connected. One end of switch C is connected to the connection point of switch A and the battery, and the other end of switch C is connected to the power supply end of the digital logic circuit on one side and the connection point of switch D in the adjacent lower level battery controller on the other side, and the switches D of the adjacent battery controllers are connected in series, and the switches C and D are used for controlling the power supply mode and the communication level setting of the digital logic circuit; The digital logic circuit is connected to the level converter through a bidirectional communication link, and the power supply end of the level converter is connected to the two ends of switch D, and the level converters of the adjacent battery controllers are connected in series through a bidirectional communication link; The MCU controller is used for collecting the power information of each battery, determining the working mode of the corresponding battery according to the power information of the battery, adjusting the switch state in the battery controller, realizing the battery access switching, and ensuring the power supply of the level converter and the digital logic circuit; And the adaptive communication level conversion of the potential difference between the adjacent level battery controllers is completed through the level converter, and the two ends of the level converter are high and low respectively, when the battery is normally accessed, the high and low levels differ by one battery voltage; when the battery is bypassed, the voltages at the two ends of the level converter are the same, realizing the communication between the battery controllers of different levels.

[0023] In the second aspect, the application provides a management method for a series battery management system, each battery in the series battery is correspondingly configured with a battery controller, the battery controllers are connected in series through a communication link, and communicate with an MCU controller; the MCU controller and the battery controller both work in a low-voltage power supply domain, and adopt a non-isolated interface for data transmission, and the management method comprises the following steps of: The MCU controller acquires the power information of each battery in the series battery through the series communication link, and determines the working mode of the corresponding battery according to the power information of the battery; According to the working mode of the battery, the switch state in the battery controller is adjusted, the battery access switching is realized, and the power supply of the level converter and the digital logic circuit is ensured; Meanwhile, adaptive level conversion is performed between the adjacent level battery controllers through the level converter; the two ends of the level converter are high and low respectively, when the battery is normally accessed, the high and low levels differ by one battery voltage; when the battery is bypassed, the voltages at the two ends of the level converter are the same, realizing the communication between the battery controllers of different levels.

[0024] Further, the adjustment of the switch state in the battery controller according to the working mode of the battery, the realization of the battery access switching, and the ensuring of the power supply of the level converter and the digital logic circuit comprise the following steps of: detecting the power information of the battery; If in normal working mode, the gating switch A and switch C are selected, the battery is connected, the high level of the battery in this stage is connected to the digital logic circuit and the low level of the level converter through the switch A and C, the high level of the level converter is powered by the battery in the upper stage, and the level converter and the digital logic circuit are ensured to work normally. If in abnormal working mode, the gating switch B and switch D are selected, the battery is bypassed, the power supply of the battery in the upper stage is connected to the high and low levels of the digital logic circuit and the level converter through the switch B and D, and the level converter and the digital logic circuit are ensured to work normally.

[0025] Further, the adaptive level conversion through the level converter according to the potential difference between the adjacent stage battery controllers comprises: the low level VB_n and the high level VC_n of the nth stage battery are obtained, and the single battery voltage V0 is calculated; when the battery is connected; the power supply voltage of the nth stage digital logic circuit is equal to the low level of the nth stage battery plus the single battery voltage, that is, VDD_n=VC_n=VB_n+V0; the communication low level of the nth stage digital logic circuit is equal to the low level of the nth stage battery plus the single battery voltage, that is, VL_n=VB_n+V0, and the communication high level is equal to the low level of the nth stage battery plus twice the single battery voltage, that is, VH_n=VB_n+2*V0; when the battery is bypassed; the nth stage digital circuit is powered by the nth+1 stage, that is, VDD_(n)=VL_n+1=VB_n+1+V0=VB_n+V0; the communication low level and the communication high level are equal to the low level of the nth stage battery plus the single battery voltage, that is, VL_n=VH_n=VB_n+V0; according to the potential difference of the communication level, the signal level is shifted up, down or horizontally converted by the level converter, and the normal communication with the adjacent stage battery controller is realized.

[0026] Further, the level conversion of the signal level up, down or horizontally conversion according to the potential difference of the communication level comprises: when the battery is connected, the level converter shifts the digital signal level output by the nth stage by one single battery voltage, so as to match the communication level of the nth+1 stage; or the level converter shifts the digital signal level output by the nth+1 stage by one single battery voltage, so as to match the communication level of the nth stage; when the battery is bypassed, the level converter horizontally converts the digital signal level output by the nth stage, and keeps the same communication level as the nth+1 stage.

[0027] In a third aspect, the present application provides a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and the computer program is executed by a processor to implement the management method.

[0028] In a fourth aspect, the present application provides a communication method for a series battery management system, wherein a communication link is used for data transmission, the communication link adopts a bidirectional communication line, the bidirectional communication line is a backup of each other, and a full-duplex mode or a half-duplex mode is selected according to a communication line state for communication.

[0029] Further, the data transmission by using the bidirectional communication line comprises: detecting working states of two communication lines in the bidirectional communication line; if both of the two communication lines are normally working, one of the two communication lines is configured as a sending line, the other is configured as a receiving line, and the full-duplex mode is used for communication; if one of the two communication lines is faulty, the remaining communication line is switched to a bidirectional half-duplex mode, in the half-duplex mode, the MCU controller sends a data packet to each level of battery controller, each level of battery controller forwards the data packet step by step and analyzes and executes, and the last level of battery controller returns a state data packet reversely after receiving the completion, and the state data packet is finally transmitted to the MCU controller step by step.

[0030] Further, in the half-duplex mode, the MCU controller sends the data packet to each level of battery controller, comprising: the MCU controller sends the data packet to the first level of battery controller through the remaining communication line; the first level of battery controller receives and analyzes the data packet, executes a corresponding control operation, and forwards the data packet to the second level of battery controller; each level of battery controller receives, analyzes, executes and forwards the data packet in turn until the last level of battery controller completes the processing; after the last level of battery controller completes the processing, the state data packet is reversely transmitted, each level of battery controller adds the state information of the level to the state data packet and transmits the state data packet to the MCU controller step by step.

[0031] Further, a frame format of the data packet is a long command frame, a long state frame, a short command frame or a short state frame, according to a transmission control mechanism of the corresponding frame, a return delay is set to adjust a communication response speed, wherein: the long command frame is used for the MCU controller to send a command to all battery controllers; the long state frame is used for all battery controllers to feed back state information to the MCU controller; the short command frame is used for the MCU controller to send a priority command to a specific battery controller; Short status frame for a specific battery controller to feedback state information to MCU controller.

[0032] In a fifth aspect, the present application provides a computer readable storage medium, wherein a computer program is stored on the computer readable storage medium, and the computer program is executed by a processor to implement the communication method.

[0033] The present application has the following advantages: The application discloses a series battery management system, which only needs a low-voltage chip and a bidirectional series communication link of a non-isolated communication interface on hardware.

[0034] The application discloses a series battery pack management method, which realizes management of each battery through a control unit and a plurality of battery controllers connected in series. The battery controller adopts a non-isolated communication interface and comprises a switch A, a switch B, a switch C, a switch D, a digital logic circuit and a level converter, so that the battery can be connected in bypass and power supply switching is realized. The level converter is converted according to a potential difference of adjacent levels, so that normal communication of different levels of controllers is ensured. The communication link adopts a double-line backup design and supports full-duplex and half-duplex modes. The application solves the problem of management of each battery in a series battery pack, realizes flexible bypass control of the battery, reliable communication transmission and power supply switching in case of failure, and improves the reliability and communication efficiency of the system.

[0035] The application discloses a communication method for a series battery management system. The application solves the key problems of abnormal battery processing, cross-voltage domain communication and real-time management in a series battery pack, and improves the use efficiency and safety of the battery pack.

[0036] Other features and advantages of the present application will be illustrated in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0037] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the different views of the drawings.

[0038] Figure 1 A comparison diagram of a traditional battery pack full series architecture and a new system battery pack bypass architecture in the background art is shown.

[0039] Figure 2 A schematic diagram of a series battery management system circuit is shown in accordance with one embodiment of the present application.

[0040] Figure 3 A schematic diagram of battery access, level shifter and digital logic circuit power supply when the battery is in normal operating mode is shown in accordance with one embodiment of the present application.

[0041] Figure 4 A schematic diagram of battery access, level shifter with high and low levels differing by one battery voltage for level up when the battery is in normal operating mode is shown in accordance with one embodiment of the present application.

[0042] Figure 5 A schematic diagram of battery access, level shifter with high and low levels differing by one battery voltage for level down when the battery is in normal operating mode is shown in accordance with one embodiment of the present application.

[0043] Figure 6 A schematic diagram of battery bypass, level shifter and digital logic circuit power supply when the battery is in abnormal operating mode is shown in accordance with one embodiment of the present application.

[0044] Figure 7 A schematic diagram of battery access, level shifter with high and low levels being the same for level pass through when the battery is in abnormal operating mode is shown in accordance with one embodiment of the present application.

[0045] Figure 8 A schematic diagram of battery access, level shifter with high and low levels being the same for level pass through when the battery is in abnormal operating mode is shown in accordance with one embodiment of the present application.

[0046] Figure 9 A schematic diagram of series battery management system bidirectional communication link when both links are operating normally is shown in accordance with one embodiment of the present application.

[0047] Figure 10 A schematic diagram of series battery management system bidirectional communication link when one of the links is inoperative and the remaining link switches to bidirectional half duplex mode is shown in accordance with one embodiment of the present application. DETAILED DESCRIPTION

[0048] Reference will now be made to the preferred embodiments of the present application in detail. While the application will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the application to these embodiments alone. On the contrary, the application includes all alternatives, modifications and equivalents falling within the spirit and scope of the appended claims.

[0049] Example 1

[0050] Figure 2A series battery management system circuit diagram according to one embodiment of the present application is shown.

[0051] The present application provides a series battery management system, including an MCU controller and a battery controller configured for each battery in a series battery, each battery controller is connected in series through 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 farthest from the MCU controller is set as the n+1 level, the MCU controller and each battery controller work in a low-voltage power domain, and a non-isolated interface is used for data transmission, wherein; The battery controller includes a switch A, a switch B, a switch C, a switch D, a digital logic circuit and a level converter. The switch A is connected in series with the battery to form a branch, the switch B is connected in parallel with the series branch formed by the switch A and the battery, and the switches A and B are used to control whether the battery is connected. One end of the switch C is connected to the connection point of the switch A and the battery, and the other end of the switch C is connected to the power supply end of the digital logic circuit on one hand and the connection point of the switch D and the switch D in the adjacent lower-level battery controller on the other hand, the switches D in the adjacent battery controllers are connected in series, and the switches C and D are used to control the power supply mode of the digital logic circuit and the communication level setting. The digital logic circuit is connected to the level converter through a bidirectional communication link, the power supply end of the level converter is connected to both ends of the switch D, and the level converters in the adjacent battery controllers are connected in series through 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 according to the power information of the battery, adjust the switch state in the battery controller, realize the battery connection switching, and ensure the power supply of the level converter and the digital logic circuit. And the level converter completes the adaptive communication level conversion of the potential difference between the adjacent level battery controllers, the two ends of the level converter are respectively high level and low level, when the battery is normally connected, the high level and the low level differ by one battery voltage, when the battery is bypassed, the voltages at both ends of the level converter are the same, and the communication between battery controllers of different levels is realized.

[0052] In the present embodiment, as shown in Figure 2 Each battery is defined as a level, starting from the MCU as the first level, followed by the second level, the third level, and so on.

[0053] VB_n is the low level of the n-level battery, VC_n is the high level of the n-level battery, and the difference between the high level and the low level is V0. Different types of batteries have different V0, and a typical lithium ion battery has V0=3.7V.

[0054] When the battery in this section is normal, VC_n supplies power to the digital circuit in this section; when the battery in this section is abnormal, the upper VC_n+1 supplies power to the digital circuit in this section. In the above two cases, the positive and negative level difference of the digital circuit is V0.

[0055] VL_n is the communication low level of the nth stage, and VH_n is the communication high level of the nth stage. Both of them supply power to the level converter to move the signal output V0 voltage difference of this stage up or down by one V0, and communicate with the adjacent stage.

[0056] The MCU works in the low voltage domain, and the positive and negative voltage difference is V0. The MCU directly communicates with the first stage and communicates with other stages through the communication link; the MCU and the battery controller follow a unified communication protocol.

[0057] Embodiment 2

[0058] Figure 3 A schematic diagram of the power supply of the battery access, the level converter and the digital logic circuit when the battery is in the normal working mode according to an embodiment of the application is shown.

[0059] Figure 6 A schematic diagram of the power supply of the battery bypass, the level converter and the digital logic circuit when the battery is in the abnormal working mode according to an embodiment of the application is shown.

[0060] The application provides a management method for a series battery management system, a battery controller is configured for each battery in the series battery, the battery controllers are connected in series through a communication link and communicate with an MCU controller; the MCU controller and the battery controller both work in a low voltage power supply domain, use a non-isolated interface for data transmission, and the management method comprises the following steps: The MCU controller obtains the power information of each battery in the series battery through the series communication link, and determines the working mode of the corresponding battery according to the power information of the battery; According to the working mode of the battery, the switch state in the battery controller is adjusted to realize battery access switching and ensure the power supply of the level converter and the digital logic circuit; At the same time, the potential difference between the adjacent battery controllers is adaptively converted by the level converter; the high level and the low level are respectively at both ends of the level converter, when the battery is normally accessed, the high level and the low level differ by one battery voltage; when the battery is bypassed, the voltages at both ends of the level converter are the same, realizing the communication between the battery controllers of different levels.

[0061] Specifically, the step of adjusting the switch state in the battery controller according to the working mode of the battery to realize battery access switching and ensure the power supply of the level converter and the digital logic circuit comprises the following steps: detecting the power information of the battery; If in normal working mode, the on-off switch A and switch C are selected, the battery is connected, the high level of the battery in this stage is connected to the digital logic circuit and the low level of the level converter through the switch A and C, the high level of the level converter is powered by the upper battery, and the level converter and the digital logic circuit are ensured to work normally. If in abnormal working mode, the on-off switch B and switch D are selected, the battery is bypassed, the power supply of the upper battery is connected to the high and low levels of the digital logic circuit and the level converter through the switch B and D, and the level converter and the digital logic circuit are ensured to work normally.

[0062] In the embodiment, when each battery works normally, the switch A and switch C are selected. The power supply relationship of the nth stage and the n+1th stage is as follows Figure 3 Black highlight.

[0063] The power supply VDD_n of the nth stage digital circuit = VB_n + V0; The high level of the nth stage digital signal = VDD_n = VB_n + V0; The low level of the nth stage digital signal = VB_n; The power supply VDD_n+1 of the n+1th stage digital circuit = VB_n+1 + V0 = VB_n + 2*V0; The high level of the n+1th stage digital signal = VDD_n+1 = VB_n + 2*V0; The low level of the n+1th stage digital signal = VB_n+1 = VB_n + V0; It can be seen that the digital signal level of the n+1th stage is higher than that of the nth stage by V0, and therefore, the signal transmission from the nth stage to the n+1th stage needs to be level-shifted by V0 through the level converter circuit.

[0064] The level converter is powered by VH_n / VL_n: VL_n = VB_n + V0; VH_n = VB_n + 2*V0; The communication level relationship of the nth stage and the n+1th stage is as follows Figure 4 、 5 as shown, Figure 4 A schematic diagram showing that the battery is connected in the normal working mode of the battery, and the high and low levels of the level converter are different by one battery voltage for level shifting. Figure 5 A schematic diagram showing that the battery is connected in the normal working mode of the battery, and the high and low levels of the level converter are different by one battery voltage for level shifting.

[0065] In the embodiment, it is assumed that the nth battery is bypassed by the switch B due to failure, at which time the switch B and the switch D are selected. The power supply relationship of the nth stage and the n+1th stage is as follows Figure 6Black highlight.

[0066] The nth stage digital circuit power supply VDD_n = VB_n + V0 (at this time, the battery of the current stage fails, the power supply is transmitted from the nth+1 stage through the closing of switch D, VDD_(n) = VL_n+1 = VB_n+1 + V0. At the same time, since switch B bypasses the nth stage battery, VB_(n) = VB_(n+1), so VDD(n) = VB(n) + V0); The nth stage digital signal high level = VDD_n = VB_n + V0; The nth stage digital signal low level = VB_n; The nth+1 stage digital circuit VDD_n+1 = VB_n+1 + V0 = VB_n + V0; The nth+1 stage digital signal high level = VDD_n+1 = VB_n + V0; The nth+1 stage digital signal low level = VB_n+1 = VB_n; It can be seen that the nth+1 stage digital signal level is the same as the nth stage. At this time, the level shifter circuit shifts the level. The level shifter is powered by VH_n / VL_n: VL_n = VH_n = VB_n + V0; The communication level relationship between the nth stage and the nth+1 stage is as shown in Figure 7 、 8 , which are one of the schematic diagrams of the level shifter when the battery is connected in the abnormal working mode, the high and low levels of the level shifter are the same, and the level is shifted.

[0067] Embodiment 3

[0068] The application provides a computer readable storage medium, a computer program is stored on the computer readable storage medium, and the computer program is executed by a processor to realize the management method.

[0069] Embodiment 4

[0070] The application provides a communication method used in a series battery management system, a bidirectional communication line is used for data transmission, the bidirectional communication lines are backup for each other, and full-duplex mode or half-duplex mode is selected according to the communication line state to perform communication.

[0071] Further, the data transmission by the bidirectional communication line comprises: detecting working states of the two communication lines in the bidirectional communication line; if both of the two communication lines are normally working, one of the two communication lines is configured as a sending line and the other is configured as a receiving line, and full-duplex mode is used for communication; if one of the two communication lines is faulty, the remaining communication line is switched to a bidirectional half-duplex mode; in the half-duplex mode, the MCU controller sends data packets to the battery controllers at all levels; the battery controllers at all levels forward the data packets step by step and analyze and execute; and the last-level battery controller returns a state data packet reversely after receiving the completion, and the state data packet is finally transmitted to the MCU controller step by step.

[0072] Further, in the half-duplex mode, the MCU controller sends data packets to the battery controllers at all levels, comprising: the MCU controller sends data packets to the first-level battery controller through the remaining communication line; the first-level battery controller receives and analyzes the data packets, performs corresponding control operations, and forwards the data packets to the second-level battery controller; the battery controllers at all levels receive, analyze, execute and forward the data packets in turn until the last-level battery controller completes processing; after the last-level battery controller completes processing, the last-level battery controller starts to reversely transmit a state data packet, and each battery controller at all levels adds state information of the level to the state data packet and transmits the state data packet to the MCU controller step by step.

[0073] Further, the frame format of the configuration data packet is a long command frame, a long state frame, a short command frame or a short state frame, according to a transmission control mechanism of the corresponding frame, a return delay is set to adjust a communication response speed, wherein: the long command frame is used for the MCU controller to send a command to all battery controllers; the long state frame is used for all battery controllers to feed back state information to the MCU controller; the short command frame is used for the MCU controller to send a priority command to a specific battery controller; and the short state frame is used for the specific battery controller to feed back state information to the MCU controller.

[0074] In the embodiment, the serial communication system is composed of two data lines, and each line supports bidirectional communication. The two data lines are backup for each other.

[0075] When both of the two data lines are normally working, the system is configured in a TX / RX mode, in which the MCU transmits data to the battery controllers as TX, and vice versa as RX. The TX / RX two signal lines can work respectively, which improves the data transmission efficiency.

[0076] When one of the data lines fails, the remaining data line will be configured as TRX mode, at which time the data is transmitted in a bidirectional half-duplex mode. That is, the MCU first transmits a data packet to the battery controller, and the battery controller forwards the data packet step by step and analyzes and executes. When the last stage receives the data packet, it returns a status data packet in the reverse direction, which is transmitted step by step and finally reaches the MCU. A complete communication cycle is completed.

[0077] The TX / RX mode link topology is shown in Figure 9 、 10 , Figure 9 For a series battery management system bidirectional communication link to work normally, it is in TX / RX mode. Figure 10 For a series battery management system bidirectional communication link to work normally, it is in TX / RX mode.

[0078] The communication protocol is used for the MCU and the battery controller to control and exchange data. The entire communication protocol is divided into a physical layer, a data link layer, and an application layer.

[0079] Among them, the communication physical layer adopts TX / RX dual-line communication, each line supports bidirectional transmission; the data link layer defines the frame format of the communication; and the application layer defines the specific battery management protocol data format and acquisition method according to different battery pack architectures and application scenarios.

[0080] Specifically, the physical layer adopts two signal lines of TX / 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 as a bidirectional half-duplex mode transmission.

[0081] Since the entire communication link is powered by the battery pack, the power supply voltages of different levels of battery pack nodes are different, with a difference of a V0 level. Therefore, different levels of circuits cannot directly communicate, and a level converter needs to be inserted to transmit logic signals between different voltage domains. In the normal communication mode, the voltage difference between the n-1 section battery and the n section battery is V0, so the n-1 section TX signal needs to be shifted by V0 level to communicate with the n section. Conversely, the n section RX signal needs to be shifted down by V0 to communicate with the n-1 section.

[0082] When the n section battery fails, it is switched through the A / B switch, at which time Figure 10The nth battery is bypassed. VL_n is still equal to (n-1)*V0, and VH_n is powered by VH_n+1, with a level of n*V0. The nth+1 battery VL_n+1=(n-1)*V0 (since one battery is bypassed, the entire battery pack voltage drops V0), and the high level VH_n+1=n*V0. That is, the nth battery and the nth+1 battery can directly communicate since they are in the same power domain (at this time, the level shifter circuit is still working, but since there is no voltage difference between the input voltage domain and the output voltage domain, the level shifter is equivalent to shifting the signal). In the case of a multi-battery failure, as the faulty battery is cut out, the entire battery pack voltage will drop. However, the remaining battery pack can still communicate. The communication level will adaptively move with the battery switching.

[0083] The physical layer communicates bit by bit according to the baud rate.

[0084] Physical layer address: Each battery on the resistance string needs a physical address, according to the distance from the MCU as 1 / 2 / … / N. Address 0 is reserved as a broadcast address.

[0085] The physical layer supports static address and dynamic address resolution protocols.

[0086] When using static addresses, chip pins or fuses can be used for static addressing.

[0087] If the controller does not have extra pins or fuses for static addressing, dynamic address protocol can also be used to automatically initialize each controller. The system completes the addressing of each controller chip through the initialization address bootstrap protocol.

[0088] Specifically, the data link layer defines a frame format. Each battery is allocated a 64-bit payload, and then the information of the current battery is loaded. The information is loaded by each battery. Chain communication is used, which is easy to expand.

[0089] The data frame can be divided into command frames and status frames, and each type of frame can be divided into long and short modes, so there are four frame formats, as shown in Table 1.

[0090] Table 1

[0091] The specific frame format is shown in Table 2. Table 2

[0092] Header: fixed as 0x7e; P1~PN: Payload for N batteries.

[0093] Long and short command frames are shown in Tables 3 and 4. Table 3

[0094] Table 4

[0095] Transmission control: In order to challenge and control the response speed of the link, the reply corresponding time (delay) can be set in the command frame, that is, the time that the system needs to wait after the command is sent to the last node. For example, in the battery measurement command, because the communication transmission speed is relatively fast, when the last node receives the command, most of the battery measurement has not been completed, so a period of time needs to be waited for, and when all the nodes complete the measurement, the last node starts to send back the status data packet through RX.

[0096] Transmission control is realized by the return delay in the above-mentioned control register.

[0097] Error control: The protocol defines a timeout mechanism, when the MCU does not receive the communication return of the battery within the specified time, the retransmission mechanism or the system reset mechanism is triggered.

[0098] Specifically, the application layer includes a protocol layer, which defines the information (voltage, current, etc.) that needs to be collected by each battery. The package is in the load of the data link layer. According to different BMS system applications, the content can be specifically defined. Each load package size is 8 bytes, of which the first byte is the address of the current level, the following six bytes are the application layer data, and the last byte is the CRC8 check result of the data of the current level. When TX transmission, P1~PN is the command frame, and when RX transmission, P1~PN is the status frame The application layer can be defined by the user. For example, for a small BMS system of lithium batteries, the 6-byte user information can be defined as follows: The command frame configures the controller parameters and working mode of each battery, triggers measurement, manages the battery, etc., as shown in Table 5; and the status frame load package is defined as shown in Table 6 when it is in the state. Table 5

[0099] Table 6

[0100] Embodiment 5

[0101] The application provides a computer readable storage medium, the computer readable storage medium stores a computer program, and the computer program is executed by a processor to realize the communication method.

[0102] Having described various embodiments of the application, it is to be understood that the above description is meant to be illustrative only, and that many modifications and variations of the embodiments are possible without departing from the scope and spirit of the described embodiments. Many modifications and variations of the described embodiments are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the described embodiments can be practiced otherwise than as specifically described.

Claims

1. A series battery management system, characterized in that: It includes an MCU controller and a battery controller corresponding to 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 farthest from the MCU controller is set as the Nth level. The MCU controller and each battery controller all operate in a low-voltage power domain and use a non-isolated interface for data transmission, wherein; The battery controller includes switch A, switch B, switch C, switch D, a digital logic circuit and a 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 hand, and to the connection point between switch D and the switch D in the adjacent lower-level battery controller on the other hand. 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 end of the level converter is connected to both ends of the switch D, and the level converters of adjacent battery controllers are connected in series via the bidirectional communication link; The MCU controller is used to collect power information of each battery, determine the working mode of the corresponding battery according to the battery 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; And the adaptive communication level conversion of the potential difference between adjacent battery controllers is completed through the level converter; The two ends of the level converter are high and low respectively. When the battery is connected normally, the difference between the high and low levels is one battery voltage; when the battery is bypassed, the voltages at both ends of the level converter are the same, enabling communication between battery controllers of different levels.

2. A management method adopted by the series battery management system according to claim 1, characterized in that A battery controller is configured for each battery in the series battery, and each battery controller is connected in series via a communication link and communicates with the MCU controller; the MCU controller and the battery controller both operate in a 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 battery in the series battery through the series communication link and determines the working mode of the corresponding battery according to the battery power information; According to the battery's operating mode, the switch state in the battery controller is adjusted to implement battery access switching and ensure power supply to the level converter and digital logic circuits; At the same time, adaptive level conversion is performed through a level converter based on the potential difference between adjacent levels of battery controllers; the two ends of the level converter are high level and low level respectively. 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, realizing communication between battery controllers of different levels.

3. The management method according to claim 2, characterized in that: The method of adjusting the switch state in the battery controller according to the operating mode of the battery to implement battery access switching and ensure power supply to the level converter and the digital logic circuit includes: Detect battery power information; If in normal working mode, switch A and switch C are turned on to connect the battery. The high level of the battery at this level is connected to the digital logic circuit and the low level of the level converter through switches A and C. The high level of the level converter is powered by the upper battery to ensure the normal operation of the level converter and the digital logic circuit. If it is in abnormal working mode, switch B and switch D are turned on to bypass the battery, and the power supply of the upper battery is connected to the high and low levels of the digital logic circuit and the level converter through the switches B and D to ensure the normal operation of the level converter and the digital logic circuit.

4. The management method according to claim 2, characterized in that Adaptive level conversion by level converter based on the potential difference between adjacent battery controllers includes: Get the low level VB_n and high level VC_n of the n-th level battery, 1≤n≤N, and calculate the single-cell battery voltage V0; When the battery is connected; The supply voltage of the n-th level digital logic circuit is equal to the low level of the n-th level battery plus the voltage of a single battery cell, that is, VDD_n=VC_n=VB_n+V0; The communication low level of the n-th level digital logic circuit is equal to the low level of the n-th level battery plus the voltage of a single battery cell VL_n= VB_n+ V0, and the communication high level is equal to the low level of the n-th level battery plus twice the voltage of a single battery cell VH_n=VB_n + 2*V0; When the battery is bypassed; The nth level digital circuit is powered by the n+1th level, that is, VDD_(n)=VL_n+1=VB_n+1+V0= VB_n+V0; The communication low level and communication high level are equal to the low level of the n-th battery plus the voltage of a single battery VL_n=VH_n=VB_n+V0; According to 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 level battery controller.

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

6. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the management method according to any one of claims 2 to 5 is implemented.

7. A communication method used by the series battery management system according to claim 1, characterized in that The communication link uses a bidirectional communication line for data transmission, the bidirectional communication lines serve as backup for each other, and selects full-duplex mode or half-duplex mode for communication according to the status of the communication line.

8. The communication method according to claim 7, wherein The use of a bidirectional communication line for data transmission includes: Detecting the working status of two communication lines in a bidirectional communication line; If both communication lines are working properly, configure one of them as a sending line and the other as a receiving line, and use full-duplex mode for communication; 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 battery controllers at all levels. Battery controllers at all levels forward the data packets step by step and parse and execute them. After the last-level battery controller receives the data packets, it returns the status data packets in reverse, which are then transmitted step by step and finally reach the MCU controller.

9. The communication method according to claim 8, wherein In the half-duplex mode, the MCU controller first sends a data packet to the battery controllers at each level, including: The MCU controller sends data packets to the first-level battery controller through the remaining communication lines; The first-level battery controller receives and parses the data packet, performs corresponding control operations, and forwards the data packet to the second-level battery controller; Each level of battery controller receives, parses, executes and forwards the data packet in sequence until the last level of battery controller completes the processing; After the last level of battery controller completes the processing, it starts to transmit the status data packet in reverse. The battery controllers at each level add the status information of this level to the status data packet in turn and transmit it to the MCU controller step by step.

10. The communication method according to claim 8, wherein: The frame format of the data packet is configured as a long command frame, a long status frame, a short command frame, or a short status frame, and a return delay is set according to the transmission control mechanism of the corresponding frame to adjust the communication response speed, wherein; Long command frame, used by the MCU controller to send commands to all battery controllers; Long status frame, used by all battery controllers to feedback status information to the MCU controller; Short command frame, used by the MCU controller to send priority commands to a specific battery controller; Short status frame, used by a specific battery controller to feedback status information to the MCU controller.

11. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the communication method according to any one of claims 7 to 10 is implemented.

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