Battery management system and method for updating firmware of slave device of battery management system

Abstract

This application relates to a battery management system and a method for updating the firmware of slave devices in the battery management system. The method involves a master control device in the battery management system updating the firmware of each slave device, including: the master control device receiving a firmware image for updating and sending the firmware image to multiple slave devices; the slave device that receives the firmware image forwarding it to other slave devices until the last slave device in a predetermined sequence receives the firmware image and sends an acknowledgment message back to the master control device. The slave devices having the firmware image use the firmware image to update their own firmware.

Description

Technical Field

[0001] This application relates to a battery management system (BMS) for a wireless daisy-chain network topology, and more particularly to a battery management system for a wireless daisy-chain network topology and a method for updating the firmware of slave devices in the battery management system. Background Technology

[0002] In previous technologies, to improve the efficiency of battery energy storage systems, battery packs in industrial and automotive battery energy storage systems were mostly arranged in series. The DC voltage of the battery pack increases with the number of batteries connected in series. However, battery energy storage systems must use a battery management system (BMS) to monitor and collect information such as the voltage and temperature of each battery to maintain the system's operation and safety. To monitor the parameters of each battery, current battery management systems can have multiple monitoring devices, and each battery can be equipped with one monitoring device. In the case of these monitoring devices forming a wireless daisy-chain network topology, there may be dozens of monitoring devices simultaneously in the wireless daisy-chain network topology. Due to the bandwidth characteristics of the wireless daisy-chain network topology, for example, the maximum data transmission unit for each device is 128 bytes, it is impossible to transmit the complete firmware image (the data volume is greater than the maximum data transmission unit of each device) for updates. Directly using manual methods (e.g., through engineers) to connect the I / O of each monitoring device one by one using update jigs and update the firmware of the monitoring devices would consume a significant amount of time and manpower. Furthermore, the high-voltage environment of battery energy storage systems poses a significant threat to human safety. Therefore, there is a need for technology that can automatically update the firmware of various battery monitoring devices within a battery management system based on a wireless daisy-chain network topology. Summary of the Invention

[0003] To address the aforementioned technical problems, the purpose of this application is to provide a battery management system based on a wireless daisy-chain network topology and a method for updating the firmware of slave devices in the battery management system. This method utilizes radio frequency couplers or optical transceivers to enable communication between battery monitoring slave devices in a series structure, and leverages the characteristics of this communication to complete firmware updates for each slave device, thereby avoiding manual operation in high-voltage environments.

[0004] The purpose of this application and the technical problem it solves are achieved by the following technical solutions. From one perspective, this application proposes a battery management system and a method for updating the firmware of slave devices in the battery management system. This application is used to update the firmware of each of N serially connected slave devices by a master control device in the battery management system. The master control device and the N slave devices are wirelessly connected in series to form a wireless daisy chain network topology. The method includes step (1): the master control device receives a firmware image for updating and sends the firmware image to the nth slave device among the N slave devices. N is a positive integer and n is a positive integer between 1 and N. The method also includes step (2): the nth slave device saves and forwards the received firmware image to the (n+k)th slave device among the N slave devices according to a predetermined order. k is a positive integer between 1 and N-1. The method also includes step (3): continue to save and forward the firmware image in a predetermined order until the last slave device in the predetermined order receives the firmware image, sends back a confirmation message to the master control device, and uses the firmware image to update the firmware of the N slave devices that have the firmware image.

[0005] In another aspect of this application, a battery management system is provided, including a master control device and N slave devices wirelessly connected in series. The master control device and the N slave devices form a wireless daisy-chain network topology. Updating the firmware of the N slave devices can be achieved by (1) the master control device receiving a firmware image for updating and sending the firmware image to the nth slave device among the N slave devices, where N is a positive integer and n is a positive integer between 1 and N; (2) the nth slave device saving and forwarding the received firmware image to the (n+k)th slave device among the N slave devices in a predetermined order, where k is a positive integer between 1 and N-1; (3) continuing to save and forward the firmware image in a predetermined order until the last slave device in the predetermined order receives the firmware image and sends back an acknowledgment message to the master control device, and uses the firmware image to update the firmware of one or more slave devices among the N slave devices that have the firmware image.

[0006] To provide a better understanding of the above and other aspects of this application, specific embodiments are described below in conjunction with the accompanying drawings: Attached Figure Description

[0007] Figure 1 A schematic diagram of a battery system 1000 including a battery management system 200 according to various embodiments of this application is shown.

[0008] Figure 2The illustration shows a schematic diagram of firmware updates for a battery monitoring device using a downlink data link according to several embodiments of this application.

[0009] Figure 3 A flowchart illustrating an example procedure for updating firmware in a slave device of a battery management system according to various embodiments of this application is shown. Detailed Implementation

[0010] The foregoing descriptions and other technical contents, features, and effects of this application will be clearly presented in the following detailed description of preferred embodiments with reference to the accompanying drawings. The following descriptions of the embodiments are with reference to the accompanying drawings and are used to illustrate specific embodiments in which this application can be implemented. The foregoing descriptions and other technical contents, features, and effects of this application will be clearly presented in the following detailed description of preferred embodiments with reference to the accompanying drawings.

[0011] The accompanying drawings and descriptions are intended to be illustrative in nature, not restrictive. In the drawings, structurally similar units are denoted by the same reference numerals. Furthermore, for ease of understanding and description, the dimensions and thicknesses of each component shown in the drawings are arbitrary, but this application is not limited thereto.

[0012] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features and effects of a battery management system and a method for updating the firmware of a slave device in the battery management system according to this application.

[0013] Please refer to Figure 1 The diagram illustrates a battery system 1000 and its battery management system 200 according to an embodiment of this application. The battery system 1000 includes multiple battery cells 900j and a battery management system 200. These battery cells 900j are connected in series. During operation of the battery system 1000, these battery cells 900j need to be monitored to confirm whether battery parameters such as temperature and voltage are normal. Therefore, a battery monitoring device (battery monitoring device 200S1 (first level) to battery monitoring device 200S) needs to be provided for each battery cell 900j. N (The last level) One of the corresponding ones is used for monitoring.

[0014] like Figure 1 As shown, the battery management system 200 includes a master control device 200M (or a main control unit), and battery monitoring devices 200S1 to 200S2. N and multiple communication couplers 300j. Multiple battery monitoring devices (battery monitoring device 200S1 to battery monitoring device 200S) N(This can be referred to as a slave device relative to the master control device 200M). Each communication coupler 300j can be an optical communication coupler or an radio frequency coupler, and is installed between the master control device 200M and the battery monitoring device 200S1 (first stage), and between the battery monitoring device 200S1 (first stage) and the battery monitoring device 200S... N Between (the last level). Main control unit 200M, battery monitoring unit 200S1 to battery monitoring unit 200S N Both devices communicate wirelessly via whispers through a communication coupler 300j to the battery monitoring device 200S. N Data, messages, or information are transmitted sequentially (downlink data link) or from the battery monitoring device 200S. N Confirmation messages are sent back sequentially (uplink data link), enabling the main control device 200M, battery monitoring device 200S1 to battery monitoring device 200S2 to transmit confirmation messages in sequence. N (That is, each device forms a wireless daisy chain network topology (N is a positive integer).

[0015] In one embodiment, multiple battery monitoring devices (battery monitoring device 200S1 to battery monitoring device 200S) N Each has its own firmware required for operation. In order to update the battery monitoring devices (battery monitoring device 200S1 to battery monitoring device 200S) in the battery management system 200, N The firmware of the battery management system 200 ensures that it remains in optimal operating condition. The technology provided in this application for updating the firmware of each battery monitoring device allows for the sequential transmission of multiple firmware fragments obtained by the master control device 200M from the firmware image segmentation to the first-level battery monitoring device (e.g., the first slave device) via a downlink data link between the battery monitoring devices. The battery monitoring device then saves and forwards the received firmware fragments. After receiving all the firmware fragments, each battery monitoring device can restore the firmware image and perform a firmware update.

[0016] Please refer to Figure 2 The illustration depicts the use of a downlink data link for battery monitoring devices (battery monitoring device 200S1 to battery monitoring device 200S) according to various embodiments of this application. NThis diagram illustrates a firmware update process. In an established wireless daisy-chain network topology, on the downlink data link, the master control device 200M can appropriately (e.g., according to the maximum data transmission unit of each battery monitoring device) divide the firmware image 400 into M segments (segment 400-1 to segment 400-M) after the firmware image 400 is received (e.g., according to the maximum data transmission unit of each battery monitoring device). The master control device 200M then sends one of these M segments, such as segment 400-1, to the first-stage battery monitoring device 200S1. In some embodiments, the firmware image 400 can be transmitted directly without segmentation. After receiving segment 400-1, the first-stage battery monitoring device 200S1 saves segment 400-1 and forwards it to the second-stage battery monitoring device 200S2, and so on, continuing forwarding until the last-stage (tail slave) battery monitoring device 200S1. N Segment 400-1 was received, meaning the predetermined sequence of segments sent to each battery monitoring device is battery monitoring device 200S1, battery monitoring device 200S2, and so on, to battery monitoring device 200S... N Battery monitoring device 200S N After receiving segment 400-1, an acknowledgment message 500 is sent back via the uplink data link, for example, acknowledgment message 500-1 to the previous stage battery monitoring device 200S. (N-1) This process continues, forwarding the information to the main control device 200M. Upon receiving confirmation message 500-1, the main control device 200M can ascertain that all battery monitoring devices have received segment 400-1. It can then send another of the M segments, such as segment 400-1, to the first-stage battery monitoring device 200S1. This process is repeated until the main control device 200M sends the last of the M segments, such as segment 400-M, and the main control device 200M receives the information from the last-stage battery monitoring device 200S1. N The sent confirmation message, such as confirmation message 500-M, indicates that all battery monitoring devices have received all segments (segment 400-1 to segment 400-M).

[0017] In one embodiment, when not all battery monitoring devices in the wireless daisy-chain network topology need to be updated, the update can be specified for one or more specific battery monitoring devices in the wireless daisy-chain network topology. For example, when only battery monitoring devices 200S1, 200S3, and 200S7 need to be updated, the firmware image 400 or its segments can be forwarded and saved in a predetermined order (e.g., battery monitoring devices 200S1, 200S3, and 200S7) until the last battery monitoring device in the predetermined order (e.g., battery monitoring device 200S7) receives the firmware image.

[0018] In one embodiment, for each battery monitoring device (battery monitoring device 200S1 to battery monitoring device 200S) N After receiving all the fragments (fragment 400-1 to fragment 400-M), it can combine the fragments into a firmware image 400 and use the firmware image 400 to update the firmware of each battery monitoring device itself.

[0019] In one embodiment, each battery monitoring device has the function of reconstructing the firmware image 400. Therefore, segments 400-1 to 400-M of the firmware image 400 can be sent in any order, for example, segments 400-2, 400-5, and 400-3 can be sent sequentially until all M segments have been sent.

[0020] In one embodiment, when the main control device 200M transmits each segment, if it does not receive the last-level battery monitoring device 200S within a specific time after transmitting one of the segments, N If an acknowledgment message is sent, for example, after a timer is started following the transmission of segment 400-3, and no acknowledgment message 500-3 is received within a specific time (when the timer resets to zero), the main control device 200M will retransmit segment 400-3 until acknowledgment message 500-3 is received before sending the next segment. This ensures that all devices receive any segments sent by the main control device 200M.

[0021] The aforementioned battery monitoring devices can receive and forward each segment and confirmation message through the controller on each battery monitoring device in conjunction with the aforementioned... Figure 1The corresponding communication coupler 300j completes this (e.g., the forwarding unit in the controller), and the combination of fragments into a firmware image and the firmware update using the firmware image by each battery monitoring device can also be completed by the controller on each battery monitoring device (e.g., the combination unit and update unit in the controller). In some embodiments, the combination unit of the controller of each battery monitoring device can be used to check whether the received fragments can be completely combined into a firmware image. For example, when the combination unit of the controller of each battery monitoring device determines that the number of stored fragments is sufficient, it begins to combine the stored fragments into a firmware image.

[0022] In one embodiment, the segments can be sent by the main control device 200M within general messages. In this case, the main control device 200M sends an OTA (Over-the-air) activation message to the battery monitoring devices via the downlink data link. Upon receiving the OTA activation message, each battery monitoring device enters OTA mode. As described above, each battery monitoring device forwards the received OTA activation message to the next-level battery monitoring device until the main control device 200M receives an acknowledgment message from the last-level battery monitoring device 200SN. This indicates that all battery monitoring devices have received the OTA activation message and entered OTA mode, and the main control device 200M begins sending the segments of the firmware image. If no acknowledgment message is received from the last-level battery monitoring device 200SN, the main control device 200M will resend the OTA activation message until a corresponding acknowledgment message is received. This ensures that all devices receive the OTA activation message from the main control device 200M and enter OTA mode.

[0023] In one embodiment, when each battery monitoring device enters OTA mode, upon receiving fragments embedded in a general message, the filtering function of the controller on each battery monitoring device (e.g., a filtering unit in the controller) can be used to filter out data other than the fragments in the message, thus saving the received fragments. The received general message containing the fragments is then copied and forwarded to the next-level battery monitoring device. As discussed above, the main control device 200M may repeatedly send the same fragment if it does not receive an acknowledgment message. In such cases, each battery monitoring device that has received the same fragment can also use the filtering function of its controller (e.g., a filtering unit in the controller) to filter out the previously received identical fragments, ensuring that each battery monitoring device does not save duplicate fragments. Each battery monitoring device can reset and leave OTA mode after completing the firmware update, or if the update is not completed within a specific time or fails, it can reset and leave OTA mode.

[0024] In one embodiment, when not all battery monitoring devices in the wireless daisy-chain network topology need to be updated, specific one or more battery monitoring devices in the wireless daisy-chain network topology can be designated to enter OTA mode. For example, when only battery monitoring devices 200S1 and 200S3- need to be updated, they can be forwarded and enter OTA mode according to a predetermined order (the predetermined order is battery monitoring device 200S1, battery monitoring device 200S3-) until the last battery monitoring device in the predetermined order receives the OTA start message.

[0025] In one embodiment, the main control device 200M may also optionally have firmware update-related functions of the aforementioned battery monitoring devices, such as receiving segments, forwarding segments, filtering messages, combining segments, firmware updates, etc., to be used in different situations, such as the main control device 200M acting as a slave device of other main control devices.

[0026] Therefore, through the examples above, after each level of the battery monitoring device receives the fragments of the firmware image, they can be combined into a firmware image and the firmware of each level of the battery monitoring device can be updated. Start

[0027] Please refer to Figure 3 It illustrates a battery management system (e.g., according to one of several embodiments of this application) Figure 1 Slave devices in the battery management system 200, for example Figure 1 and Figure 2 Battery monitoring device 200S1 to battery monitoring device 200S N The flowchart shows an example procedure for performing a firmware update. In step S310, the main control device, for example... Figure 1 and Figure 2 The main control unit 200M receives the firmware image for firmware updates, for example... Figure 2 The firmware image is 400 and divided into multiple segments, for example... Figure 2 Segments 400-1 to 400-M. In step S320, the master control device sends one of the multiple segments to one of the slave devices (e.g., Figure 2 200Sn), for example through Figure 2 The downlink data link. In S330, the slave device that receives the segment determines whether it is the last-level slave device (e.g., whether it is the last-level slave device). Figure 2 Battery monitoring device 200S N If the received segment is not the last battery monitoring device in the predetermined sequence, proceed to step S340 to save the received segment and forward it to other slave devices (e.g., ...). Figure 2If the battery monitoring device 200Sn+1 or other battery monitoring device is used, proceed to step S350, save the received segment and send a confirmation message (e.g., ...). Figure 2 The confirmation message 500 is sent to the main control device, for example via... Figure 2 The uplink data link. Regardless of whether the battery monitoring device receiving the segment is the last stage, step S360 must be entered to determine whether the received segment is the last segment (e.g., whether it is the last segment). Figure 2 If the last segment sent (such as segment 400-M or other last sent segments) is not complete, then the process returns to step S320, where the main control device continues to send other segments, for example, via the same method. Figure 2 If the downlink data link is true, proceed to step S370, combine all the saved fragments into a firmware image, and use the firmware image to perform a firmware update on the slave device with the firmware image.

[0028] In one embodiment, in a specific setting, if the master control device does not receive an acknowledgment message from the last-level slave device within a specific time after sending a segment, the master control device resends the segment.

[0029] In one embodiment, in a specific configuration, the slave device filters repeatedly received segments by means of a filtering unit provided in the controller of the slave device, and saves only one identical segment.

[0030] In one embodiment, in a specific setup, before the master control device sends a segment to the slave device, the master control device sends an OTA start message to the slave device; the slave device enters OTA mode according to the received OTA start message, and forwards the OTA start message to other slave devices in a predetermined order, until the slave device at the last level of the predetermined order receives the OTA start message, enters OTA mode, and sends back an OTA confirmation message to the master control device.

[0031] In one embodiment, in a specific setting, when the main control device receives an OTA confirmation message, it appends the fragment to a general message and sends it.

[0032] In one embodiment, in a specific setting, when the slave device is in OTA mode, a filtering unit provided in the controller of the slave device filters out other data in the message except for fragments and saves the fragments, and a forwarding unit provided in the controller of the slave device copies and forwards general messages with fragments.

[0033] As described above, the technology provided in this application, within a battery management system of a wireless daisy-chain network topology, involves a master control device receiving firmware images for firmware updates of each slave device. The master control device then divides the firmware image into multiple segments and sequentially sends and forwards these segments to each slave device via a data link. This process continues until the last-level slave device sends back an acknowledgment message, ensuring that all slave devices receive all segments, assemble them into a firmware image, and update their own firmware. By using OTA (Over-The-Air) updates to send multiple segments of the divided firmware image, the maximum data transmission capacity of each device in the system is met, and firmware updates for each slave device can be completed without human intervention, thus maintaining the battery management system (BMS) at the latest performance level.

[0034] The foregoing disclosure provides various features for implementing some embodiments or examples of this application. Specific examples of components and configurations described above (e.g., mentioned values ​​or names) are used to simplify / illustrate some embodiments of this application. Of course, these components and configurations are merely examples and are not intended to be limiting. Furthermore, reference numerals and / or letters may be repeated in various instances of some embodiments of this application. This repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed. Terms such as "in one embodiment" are used repeatedly. This term does not usually refer to the same embodiment; however, it may refer to the same embodiment. Words such as "comprising," "having," and "including" are synonyms unless the context otherwise indicates otherwise.

[0035] The above description is merely a specific embodiment of this application, intended to facilitate understanding of the content of this application by those skilled in the art, and is not intended to limit this application in any way. Although this application has been disclosed above with specific embodiments, it is not intended to limit this application. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of this application. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A method for updating the firmware of slave devices in a battery management system, wherein the master control device in the battery management system updates the firmware of each of N serially connected slave devices, wherein the master control device and the N slave devices are wirelessly connected in series to form a wireless daisy-chain network topology, characterized in that, The method includes: (1) The master control device receives a firmware image for updating and sends the firmware image to the nth slave device among the N slave devices, where N is a positive integer and n is a positive integer between 1 and N; (2) The received firmware image is stored by the nth slave device and forwarded to the (n+k)th slave device among the N slave devices according to a predetermined order, where k is a positive integer between 1 and N-1; and (3) Continue to save and forward the firmware image according to the predetermined order until a slave device at the last level in the predetermined order receives the firmware image and sends back an acknowledgment message to the master control device, and uses the firmware image to perform a firmware update on one or more of the N slave devices that have the firmware image. Step (1) further includes the master control device dividing the firmware image into M segments and sending the m-th segment of the M segments to the n-th slave device among the N slave devices, where M is a positive integer and m is a positive integer between 1 and M. Step (2) further includes the nth slave device saving and forwarding the mth fragment to the (n+k)th slave device according to the predetermined order. Step (3) further includes continuing to save and forward the m-th segment according to the predetermined order until the slave device at the last level in the predetermined order receives the m-th segment and sends back the confirmation message to the master control device.

2. The method for updating the firmware of a slave device in a battery management system as described in claim 1, characterized in that, Including: (4) After receiving the confirmation message, the master control device sends the (m+i)th segment of the M segments to the nth slave device among the N slave devices, where i is a positive integer between 1 and M-1; and (5) Repeat steps (2) to (4) above to send each of the M segments in sequence until the Nth slave device receives all the M segments and sends back the confirmation message to the main control device. Each of the N slave devices, after receiving all of the M fragments, combines all of the M fragments into the firmware image.

3. The method for updating the firmware of a slave device in a battery management system as described in claim 2, characterized in that, After the master control device sends the m-th segment of the M segments, if it does not receive the confirmation message sent by the Nth slave device, the last level of the N slave devices, within a specific time, the master control device will resend the m-th segment of the M segments.

4. The method for updating the firmware of a slave device in a battery management system as described in claim 3, characterized in that, The N slave devices filter the repeatedly received m-th segment by a filtering unit provided in a controller of each of the N slave devices, and save only one m-th segment.

5. The method for updating the firmware of a slave device in a battery management system as described in claim 2, characterized in that, Before the master control device sends the m-th segment of the M segments to the n-th slave device of the N slave devices, the process includes: The master control device sends an over-the-air update start message to the nth slave device among the N slave devices; The nth slave device enters an over-the-air update mode according to the over-the-air update initiation message, and forwards the over-the-air update initiation message to the (n+k)th slave device in the nth slave device according to the predetermined order; and The over-the-air update initiation message continues to be forwarded until the slave device, which is at the last level in the predetermined sequence, receives the over-the-air update initiation message, enters the over-the-air update mode, and sends an over-the-air update confirmation message back to the master control device.

6. The method for updating the firmware of a slave device in a battery management system as described in claim 5, characterized in that, When the master control device receives the over-the-air update confirmation message, it appends the m-th fragment to a message and sends it; and when each of the N slave devices is in the over-the-air update mode, it filters out other data in the message except for the m-th fragment and saves the m-th fragment by a filtering unit of a controller of each of the N slave devices, and copies and forwards the message containing the m-th fragment by a forwarding unit of the controller of each of the N slave devices.

7. A battery management system, characterized in that, The battery management system includes: A main control device; and N slave devices connected in series wirelessly The master control device and the N slave devices form a wireless daisy-chain network topology. The firmware of the N slave devices is updated by: (1) The master control device receives a firmware image for updating and sends the firmware image to the nth slave device among the N slave devices, where N is a positive integer and n is a positive integer between 1 and N; (2) The nth slave device stores and forwards the received firmware image to the (n+k)th slave device among the N slave devices according to a predetermined order, where k is a positive integer between 1 and N-1; and (3) Save and forward the firmware image according to the predetermined order until a slave device at the last level in the predetermined order receives the firmware image and sends back an acknowledgment message to the master control device, and use the firmware image to perform a firmware update on one or more slave devices among the N slave devices that have the firmware image. The main control device further includes a segmentation unit for segmenting the firmware image into M segments, and the main control device sends the m-th segment of the M segments to the n-th slave device, where M is a positive integer and m is a positive integer between 1 and M. The nth slave device saving and forwarding the received firmware image includes saving and forwarding the mth fragment according to the predetermined order. Continuing to save and forward the firmware image according to the predetermined order includes continuing to save and forward the m-th segment until the slave device at the last level in the predetermined order receives the m-th segment and sends back the confirmation message to the master control device.

8. The battery management system as described in claim 7, characterized in that, The firmware of the N slave devices is updated by: (4) After receiving the confirmation message, the master control device sends the (m+i)th segment of the M segments to the nth slave device among the N slave devices, where i is a positive integer between 1 and M-1; as well as (5) Repeat steps (2) to (4) above to send each of the M segments in sequence until the Nth slave device receives all of the M segments and sends back the confirmation message to the main control device. Each of the N slave devices, after receiving all of the M fragments, combines all of the M fragments into the firmware image.

9. The battery management system as described in claim 8, characterized in that, The main control device further includes a timer, which, after the main control device sends the m-th segment of the M segments, if it does not receive the acknowledgment message sent by the Nth slave device, the last level of the N slave devices, within a specific time, then the main control device retransmits the m-th segment of the M segments; and each of the N slave devices includes a controller with a filtering unit, the filtering unit being used to filter the repeatedly received m-th segment and save only one m-th segment.

10. The battery management system as described in claim 7, characterized in that, Before the master control device sends the m-th segment of the M segments to the n-th slave device of the N slave devices, the following is included: The master control device sends an over-the-air update start message to the nth slave device among the N slave devices; The nth slave device enters an over-the-air update mode according to the over-the-air update initiation message, and forwards the over-the-air update initiation message to the (n+k)th slave device among the N slave devices according to the predetermined order; and The over-the-air update initiation message continues to be forwarded until the slave device, which is at the last level in the predetermined sequence, receives the over-the-air update initiation message, enters the over-the-air update mode, and sends an over-the-air update confirmation message back to the master control device.

11. The battery management system as described in claim 10, characterized in that, When the master control device receives the over-the-air update confirmation message, it appends the m-th segment to a message and sends it; and each of the N slave devices includes a controller, which includes a filtering unit and a forwarding unit. The filtering unit is used, during the over-the-air update mode, to filter out all data in the message except for the m-th fragment and to save the m-th fragment. The forwarding unit is used to copy and forward the message containing the m-th fragment.

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