A method, system, and storage medium for automatically transmitting lithium battery EOL test data.

Abstract

This invention provides a method, system, and storage medium for automatically transmitting EOL test data from lithium batteries. The method includes: S101: completing data preprocessing and verification; S102: configuring a dedicated uplink channel for EOL test data and a downlink channel for normal business data; S103: constructing an independent EOL test operation mode, and initiating the automatic transmission process of EOL test data without interfering with the core safety functions of the battery management system; S104: performing fixed-length packetization and cyclic framing on the collected cell voltage and temperature data; S105: adopting a multi-type message staggered peak period scheduling mechanism to send different types of data frames in a time-division orderly manner; S106: implementing a multi-fault tolerance mechanism based on data retransmission, anomaly filling, and status identification; S107: automatically transmitting the EOL test data to the charge / discharge test cabinet. This invention improves the communication stability, data reliability, and production efficiency of end-of-line testing in lithium battery production lines.

Description

Technical Field

[0001] This invention relates to the field of lithium battery manufacturing and battery management system technology, and in particular to a method, system and storage medium for automatically transmitting lithium battery EOL test data. Background Technology

[0002] In the mass production of lithium battery packs, the end-of-line (EOL) charge-discharge test is a crucial step in verifying the safety, consistency, and reliability of the battery pack. This test requires real-time acquisition of key data such as cell-level voltage and temperature during the charge-discharge process to determine the cell status, identify anomalies, prevent overcharging and over-discharging, and complete data traceability.

[0003] However, existing traditional technologies generally suffer from the following technical defects: First, traditional charge and discharge test cabinets can only collect the total voltage and total current signals of the battery pack, and cannot directly obtain high-precision data such as the voltage and temperature of individual cells collected inside the BMS. This results in incomplete test data, inaccurate protection logic, and failure to identify cell abnormalities in a timely manner.

[0004] Second, conventional battery management systems do not have an independent EOL test communication mode. During the test, it is necessary to switch programs, modify configurations, or restart the system, which can easily interfere with core safety functions such as normal data acquisition, fault protection, and insurance control, thus affecting system stability.

[0005] Third, when the number of battery pack strings is large and the number of battery cells is large, the amount of voltage and temperature data increases significantly. The traditional CAN bus transmission method does not adopt a reasonable packet division and scheduling mechanism, which is prone to problems such as bus congestion, message frame loss, data disorder, and timing disorder, seriously affecting the reliability of the test.

[0006] Fourth, most existing solutions use a single CAN channel to receive and send data, which causes business data and test data to compete for resources and interfere with communication, resulting in unstable data transmission and increased response delay.

[0007] Fifth, traditional EOL testing relies on manual configuration, manual triggering, wiring and debugging, which has low automation, complex operation and low production efficiency, and cannot meet the testing needs of high-speed automated production lines.

[0008] Therefore, the industry urgently needs an EOL test data outsourcing solution that can operate independently, without interfering with the system, with stable communication, and a high degree of automation. Summary of the Invention

[0009] The purpose of this invention is to address the shortcomings of existing technologies by proposing an automatic external transmission method, system, and storage medium for lithium battery EOL test data. The system achieves automatic acquisition, protocol encoding, cyclic framing, peak scheduling, and external transmission of cell voltage and temperature data through a battery management system, and works in conjunction with a charge / discharge test cabinet to complete the automatic control of factory performance testing.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for automatically transmitting lithium battery EOL test data, comprising the following steps: S101: The main control unit acquires the cell voltage and temperature measurement signals of the lithium battery pack under test, and completes data preprocessing and verification. S102: Based on the dual CAN independent channel architecture, a dedicated EOL test data uplink channel and a normal business data downlink channel are configured to achieve physical isolation and independent operation of the two communication channels. The dual CAN independent channel architecture includes two physically independent CAN controller channels. S103: Build an independent EOL test operation mode and start the automatic external transmission process of EOL test data without interfering with the core safety functions of the battery management system; S104: Performs fixed-length packetization and cyclic framing on the collected cell voltage and temperature data to generate standard data frames that conform to the CAN bus protocol; S105: Employs a multi-type message staggered periodic scheduling mechanism to send different types of data frames in a time-division and orderly manner, avoiding bus conflicts and congestion; S106: Based on multiple fault-tolerance mechanisms such as data resending, anomaly filling, and status identification, the integrity and accuracy of EOL test data transmission are guaranteed; S107: Automatically transmits EOL test data to the charge / discharge test cabinet, collaboratively completing the entire process of lithium battery factory performance testing.

[0011] Furthermore, the dual CAN independent channel architecture includes: configuring two on-chip CAN controllers, wherein the first CAN channel is dedicated to the uplink transmission of EOL test data, and the second CAN channel is used for downlink reception of normal service messages from the battery pack. The physical links of the two channels are independent of each other, isolating the data transmission and reception streams at the hardware level to avoid resource contention and communication interference between service data and test data.

[0012] Furthermore, the process of dividing the collected cell voltage and temperature data into fixed-length packets and cyclically framing them to generate standard data frames conforming to the CAN bus protocol includes: a single voltage message containing fixed valid data of 3 cells, with empty bytes filled with a first preset identifier value; a single temperature message containing fixed valid data of 6 cells, with empty bytes filled with a second preset identifier value; and cyclically numbering and framing all data according to the cell serial number order to ensure that the length of each data frame is fixed, the format is uniform, and it conforms to the CAN bus transmission standard.

[0013] Furthermore, the multi-type message staggered period scheduling mechanism is adopted to send different types of data frames in a time-division and orderly manner, including: setting the basic acquisition period to 50ms; setting the voltage message sending period to 90-110ms; setting the temperature message sending period to 190-210ms; and setting the extreme value state frame sending period to 480-520ms. Through the task hierarchical scheduling of the real-time operating system, the sending time of different types of messages is staggered to avoid bus conflicts caused by the simultaneous sending of multiple frames of data at the same time.

[0014] Furthermore, the multi-fault tolerance mechanism based on data retransmission, anomaly filling, and status identification ensures the integrity and accuracy of EOL test data transmission. This includes: automatically triggering a retransmission mechanism when a single CAN transmission fails, with the number of retransmissions set to 2 to 4; performing fixed-value anomaly filling on abnormal data frames that fail to be retransmitted, and adding an anomaly status identification to the data frame; and adding a CRC checksum to all data frames, with the receiving end identifying whether the data transmission is incorrect through the checksum.

[0015] Furthermore, the data preprocessing and verification includes: filtering and range verification of the collected raw data to remove out-of-range abnormal values; and calculating the maximum voltage, minimum voltage, average voltage, maximum temperature, minimum temperature, average temperature, and cell number corresponding to the extreme values ​​for the entire package of cells.

[0016] Furthermore, the independent EOL test operation mode can be enabled or disabled independently via external serial port commands or CAN commands, and the start / stop actions do not change the conventional acquisition logic and fault judgment logic of the battery management system.

[0017] Secondly, the present invention provides an automatic external transmission system for lithium battery EOL test data based on dual independent CAN channels, comprising: The data acquisition module is used to acquire the cell voltage and temperature measurement signals of the lithium battery pack under test through the main control unit, and to complete the data preprocessing and verification. The channel configuration module is used to configure a dedicated EOL test data uplink channel and a normal business data downlink channel based on the dual CAN independent channel architecture, so as to achieve physical isolation and independent operation of the two communication channels; The mode control module is used to build an independent EOL test operation mode and start the automatic external transmission process of EOL test data without interfering with the core safety functions of the battery management system. The data framing module is used to perform fixed-length packetization and cyclic framing of the collected cell voltage and temperature data to generate standard data frames that conform to the CAN bus protocol. The scheduling and sending module is used to employ a multi-type message staggered periodic scheduling mechanism to send different types of data frames in a time-division and orderly manner, thereby avoiding bus conflicts and congestion. The fault tolerance verification module is used to ensure the integrity and accuracy of EOL test data transmission based on multiple fault tolerance mechanisms such as data resending, anomaly filling, and status identification. The collaborative testing module is used to automatically send EOL test data to the charge and discharge test cabinet, collaboratively completing the entire process of lithium battery factory performance testing.

[0018] Furthermore, two CAN controllers are configured inside the main control unit. The first CAN channel is dedicated to the uplink transmission of EOL test data, and the second CAN channel is used for downlink reception of normal service messages from the battery pack. The physical links of the two channels are independent of each other. The data framing module includes: a voltage framing unit, used to packetize the cell voltage data into frames of 3 voltage values, with empty bytes filled with 0xFFFF; a temperature framing unit, used to packetize the cell temperature data into frames of 6 temperature values, with empty bytes filled with 0xFF; and a cyclic numbering unit, used to cyclically number and frame all data according to the cell serial number order. The scheduling and sending module includes: a period configuration unit, used to configure the basic acquisition period as 50ms, the voltage message sending period as 90-110ms, the temperature message sending period as 190-210ms, and the extreme value state frame sending period as 480-520ms; and a task scheduling unit, used to stagger the sending times of different types of messages through task hierarchical scheduling of the real-time operating system. The fault tolerance verification module includes: a retransmission unit, which automatically triggers a retransmission mechanism when a single CAN transmission fails, and the number of retransmissions is 2 to 4; an anomaly filling unit, which fills the anomaly data frame with a fixed value; a status identification unit, which adds an anomaly status identification to the anomaly data frame; and a verification unit, which adds a CRC check code to all data frames.

[0019] Thirdly, the present invention provides a computer-readable storage medium on which a computer program is stored, wherein the computer program, when executed by a processor, implements the method as described in any one of the above.

[0020] Compared with existing technologies, this invention relies on the AT32F403A main control chip and the FreeRTOS real-time operating system to build a hardware and software platform. Through dual CAN hardware channel partitioning, hierarchical task scheduling, fixed-length data packetization, time-sharing peak transmission, and multiple fault tolerance checks, it solves the technical problems of existing EOL test communication interference, message congestion, low automation, and data loss. It realizes fully automatic, highly reliable, and interference-free transmission of EOL test data, significantly improving the efficiency, stability, and data integrity of end-of-line testing of lithium battery production lines.

[0021] The advantages and positive effects of this invention are as follows: Communication isolation: Physical isolation between test data uplink and business data downlink is achieved through dual independent CAN channels, fundamentally avoiding mutual interference between data streams and ensuring communication stability.

[0022] System safety: An independent EOL test operation mode is constructed, and the start and stop are controlled separately through external commands without interfering with the core safety functions of the BMS (overvoltage protection, overtemperature protection, fault detection, etc.), ensuring the safe operation of the battery management system during the test.

[0023] Bus efficiency: Through fixed-length packetization, cyclic framing and off-peak periodic scheduling mechanisms, CAN bus conflicts and congestion are effectively avoided. Even in a large data scenario with 96 battery cells, the bus load can still be controlled within 30%.

[0024] Data reliability: Through multiple fault-tolerance measures such as resending mechanism, anomaly filling, and CRC check, the integrity and accuracy of EOL test data are guaranteed, with a packet loss rate of <0.05%.

[0025] Automation level: It realizes the fully automatic collection, processing and transmission of EOL test data, and works in conjunction with the charge and discharge test cabinet to complete the factory performance test without manual intervention, which greatly improves production efficiency. Attached Figure Description

[0026] Figure 1 This is a block diagram of the overall architecture of the system of the present invention; Figure 2 This is a flowchart illustrating the overall workflow of the EOL test data automatic external transmission method of the present invention. Figure 3 This is a schematic diagram of the packetization and framing of voltage and temperature data in this invention. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0028] Please see Figures 1-3 In a first aspect, the present invention provides a method for automatically transmitting lithium battery EOL test data, comprising the following steps: S101: The main control unit acquires the cell voltage and temperature measurement signals of the lithium battery pack under test, and completes data preprocessing and verification. S102: Based on the dual CAN independent channel architecture, a dedicated EOL test data uplink channel and a normal business data downlink channel are configured to achieve physical isolation and independent operation of the two communication channels. The dual CAN independent channel architecture includes two physically independent CAN controller channels. S103: Build an independent EOL test operation mode and start the automatic external transmission process of EOL test data without interfering with the core safety functions of the battery management system; S104: Performs fixed-length packetization and cyclic framing on the collected cell voltage and temperature data to generate standard data frames that conform to the CAN bus protocol; S105: Employs a multi-type message staggered periodic scheduling mechanism to send different types of data frames in a time-division and orderly manner, avoiding bus conflicts and congestion; S106: Based on multiple fault-tolerance mechanisms such as data resending, anomaly filling, and status identification, the integrity and accuracy of EOL test data transmission are guaranteed; S107: Automatically transmits EOL test data to the charge / discharge test cabinet, collaboratively completing the entire process of lithium battery factory performance testing.

[0029] Furthermore, the dual CAN independent channel architecture includes: configuring two on-chip CAN controllers, wherein the first CAN channel is dedicated to the uplink transmission of EOL test data, and the second CAN channel is used for downlink reception of normal service messages from the battery pack. The physical links of the two channels are independent of each other, isolating the data transmission and reception streams at the hardware level to avoid resource contention and communication interference between service data and test data.

[0030] Furthermore, the process of dividing the collected cell voltage and temperature data into fixed-length packets and cyclically framing them to generate standard data frames conforming to the CAN bus protocol includes: a single voltage message containing fixed valid data of 3 cells, with empty bytes filled with a first preset identifier value; a single temperature message containing fixed valid data of 6 cells, with empty bytes filled with a second preset identifier value; and cyclically numbering and framing all data according to the cell serial number order to ensure that the length of each data frame is fixed, the format is uniform, and it conforms to the CAN bus transmission standard.

[0031] Furthermore, the multi-type message staggered period scheduling mechanism is adopted to send different types of data frames in a time-division and orderly manner, including: setting the basic acquisition period to 50ms; setting the voltage message sending period to 90-110ms; setting the temperature message sending period to 190-210ms; and setting the extreme value state frame sending period to 480-520ms. Through the task hierarchical scheduling of the real-time operating system, the sending time of different types of messages is staggered to avoid bus conflicts caused by the simultaneous sending of multiple frames of data at the same time.

[0032] Furthermore, the multi-fault tolerance mechanism based on data retransmission, anomaly filling, and status identification ensures the integrity and accuracy of EOL test data transmission. This includes: automatically triggering a retransmission mechanism when a single CAN transmission fails, with the number of retransmissions set to 2 to 4; performing fixed-value anomaly filling on abnormal data frames that fail to be retransmitted, and adding an anomaly status identification to the data frame; and adding a CRC checksum to all data frames, with the receiving end identifying whether the data transmission is incorrect through the checksum.

[0033] Furthermore, the data preprocessing and verification includes: filtering and range verification of the collected raw data to remove out-of-range abnormal values; and calculating the maximum voltage, minimum voltage, average voltage, maximum temperature, minimum temperature, average temperature, and cell number corresponding to the extreme values ​​for the entire package of cells.

[0034] Furthermore, the independent EOL test operation mode can be enabled or disabled independently via external serial port commands or CAN commands, and the start / stop actions do not change the conventional acquisition logic and fault judgment logic of the battery management system.

[0035] Secondly, the present invention provides an automatic external transmission system for lithium battery EOL test data based on dual independent CAN channels, comprising: The data acquisition module is used to acquire the cell voltage and temperature measurement signals of the lithium battery pack under test through the main control unit, and to complete the data preprocessing and verification. The channel configuration module is used to configure a dedicated EOL test data uplink channel and a normal business data downlink channel based on the dual CAN independent channel architecture, so as to achieve physical isolation and independent operation of the two communication channels; The mode control module is used to build an independent EOL test operation mode and start the automatic external transmission process of EOL test data without interfering with the core safety functions of the battery management system. The data framing module is used to perform fixed-length packetization and cyclic framing of the collected cell voltage and temperature data to generate standard data frames that conform to the CAN bus protocol. The scheduling and sending module is used to employ a multi-type message staggered periodic scheduling mechanism to send different types of data frames in a time-division and orderly manner, thereby avoiding bus conflicts and congestion. The fault tolerance verification module is used to ensure the integrity and accuracy of EOL test data transmission based on multiple fault tolerance mechanisms such as data resending, anomaly filling, and status identification. The collaborative testing module is used to automatically send EOL test data to the charge and discharge test cabinet, collaboratively completing the entire process of lithium battery factory performance testing.

[0036] Furthermore, two CAN controllers are configured inside the main control unit. The first CAN channel is dedicated to the uplink transmission of EOL test data, and the second CAN channel is used for downlink reception of normal service messages from the battery pack. The physical links of the two channels are independent of each other. The data framing module includes: a voltage framing unit, used to packetize the cell voltage data into frames of 3 voltage values, with empty bytes filled with 0xFFFF; a temperature framing unit, used to packetize the cell temperature data into frames of 6 temperature values, with empty bytes filled with 0xFF; and a cyclic numbering unit, used to cyclically number and frame all data according to the cell serial number order. The scheduling and sending module includes: a period configuration unit, used to configure the basic acquisition period as 50ms, the voltage message sending period as 90-110ms, the temperature message sending period as 190-210ms, and the extreme value state frame sending period as 480-520ms; and a task scheduling unit, used to stagger the sending times of different types of messages through task hierarchical scheduling of the real-time operating system. The fault tolerance verification module includes: a retransmission unit, which automatically triggers a retransmission mechanism when a single CAN transmission fails, and the number of retransmissions is 2 to 4; an anomaly filling unit, which fills the anomaly data frame with a fixed value; a status identification unit, which adds an anomaly status identification to the anomaly data frame; and a verification unit, which adds a CRC check code to all data frames.

[0037] Thirdly, the present invention provides a computer-readable storage medium on which a computer program is stored, wherein the computer program, when executed by a processor, implements the method as described in any one of the above.

[0038] Specifically, the overall system architecture of this invention is as follows: Figure 1 As shown, the system's hardware includes the following components: 1. Main control unit The system employs the Arterium AT32F403A (Cortex-M4 core) microcontroller as its core for computation and task scheduling. This chip boasts high real-time performance and stability, making it suitable for the environmental requirements of industrial-grade lithium battery production and testing scenarios. In other embodiments, other ARM Cortex-M series microcontrollers with equivalent or higher performance can also be used.

[0039] 2. Dual CAN communication peripherals The chip is equipped with two on-chip CAN controllers. The first CAN channel (e.g., CAN1) is dedicated to the uplink output of EOL test data, while the second CAN channel (e.g., CAN2) is used for downlink reception of normal service messages from the battery pack (such as smart cover pressure and temperature messages). The physical links of the two channels are independent, completely isolating the data transmission and reception streams at the hardware level to avoid resource contention and communication interference between service data and test data. CAN communication uniformly adopts a fixed baud rate of 500Kbps, CAN2.0 extended frames, and an 8-byte format per frame.

[0040] 3. SPI peripheral Configure an SPI daisy-chain bus to connect multiple external cell acquisition slave chips, enabling batch synchronous acquisition of voltage and temperature data of the entire series of cells, ensuring the real-time performance and consistency of data acquisition.

[0041] 4. Supporting peripherals Configure system timers and serial port peripherals for system timing and host computer command interaction, enabling fully automatic triggering and monitoring of the EOL test process.

[0042] II. Key Technical Parameters The key technical parameters involved in this invention are as follows: 1. Periodic parameters The basic acquisition period is fixed at 50ms (preferred value); the voltage message transmission period ranges from 90 to 110ms, preferably 100ms; the temperature message transmission period ranges from 190 to 210ms, preferably 200ms; and the extreme value state frame transmission period ranges from 480 to 520ms, preferably 500ms.

[0043] 2. Subcontracting rule parameters The valid data for a single-frame voltage message is fixed at 3 cells, with empty bytes filled with 0xFFFF; the valid data for a single-frame temperature message is fixed at 6 cells, with empty bytes filled with 0xFF. In each frame, the sequence number occupies 2 bytes, each voltage value occupies 2 bytes, and each temperature value occupies 1 byte, ensuring that the data length of each frame is fixed, the format is uniform, and it conforms to the CAN bus transmission standard.

[0044] 3. Resend parameters When a single CAN transmission fails, a retransmission mechanism is automatically triggered. The number of retransmissions ranges from 2 to 4, with a maximum of 3 retransmissions being preferred, balancing transmission efficiency and data reliability.

[0045] 4. Task Priority The FreeRTOS real-time operating system is used to configure task priorities, with the EOL test data sending task having a higher priority than the regular business data processing task. This ensures the real-time performance of the test data while also ensuring that core safety functions (such as overvoltage protection, overtemperature protection, and fuse disconnection) are not interfered with.

[0046] III. Specific Implementation Steps of the Method The following is combined with Figure 2 The overall workflow diagram of the EOL task shown below provides a detailed explanation of the specific implementation steps of this invention.

[0047] Step 1: System Initialization After the system powers on, it completes the initialization and configuration of hardware peripherals such as CAN1 / CAN2, SPI, and timers. Independent EOL test tasks, fault detection tasks, and serial port interaction tasks are created in the FreeRTOS real-time operating system, and the priorities of each task are assigned. After the EOL task initialization is complete, it enters the ready state.

[0048] Step 2: EOL Task Startup Control After an external EOL test start command is sent via serial port or CAN command, the EOL task switches from the ready state to the running state and begins the automatic EOL test data transmission process. External commands can also separately disable the EOL data transmission function. The start / stop actions do not alter the BMS's conventional data acquisition and fault diagnosis logic, ensuring that core safety functions remain unaffected throughout the process.

[0049] Step 3: Periodic Data Collection After the EOL task is started, it uses a 50ms baseline period to traverse all acquisition chips through the SPI daisy chain to batch collect the individual cell voltage data and raw temperature data of the entire series of cells.

[0050] Step 4: Data Preprocessing and Validation The collected raw voltage and temperature data are filtered to remove noise interference; range verification is performed to eliminate abnormal values ​​that exceed the range. At the same time, based on the preprocessed data, the maximum voltage, minimum voltage, average voltage, maximum temperature, minimum temperature, average temperature, and the cell number corresponding to each extreme value are calculated for the entire package of cells, generating cell extreme value state data.

[0051] Step 5: Fixed-length data packetization and cyclic framing The preprocessed data is framed according to the preset packetization rules: Voltage data subpackaging process (e.g.) Figure 3 (as shown) The voltage data of all cells in a string is split according to the rule of "3 voltage values / frame". In a single voltage frame, the sequence number occupies 2 bytes, and each voltage value occupies 2 bytes, with a single frame carrying a total of 3 valid voltage data. When the last frame has less than 3 valid data, the empty spaces are padded with 0xFFFF. All voltage frames are cyclically numbered according to the order of the cell string number, with the frame header starting from 0 and incrementing sequentially. When the maximum limit is exceeded, the frame header is reset to 0, thus achieving cyclic numbering and framing.

[0052] Temperature data subpackaging process (e.g.) Figure 3 (as shown) The temperature data of all cells in a string is split according to the rule of "6 temperature values / frame". In a single temperature frame, the sequence number occupies 2 bytes, and each temperature value occupies 1 byte, with a single frame carrying a total of 6 valid temperature data. When the last frame has less than 6 valid data, the empty spaces are padded with 0xFF. All temperature frames are cyclically numbered according to the cell string number, with the frame header starting from 0 and incrementing sequentially. When the maximum limit is exceeded, the frame header is reset to 0, thus achieving cyclic numbering and framing.

[0053] Before sending, a frame header consistency check is performed to determine whether the current frame header is consistent with the previous frame, thus avoiding duplicate transmissions, and the current frame header status is recorded.

[0054] Step 6: Time-sharing and peak-shifting scheduling for transmission Time-sharing and staggered transmission of multiple message types can be achieved through timer interrupts. For example... Figure 2 As shown, the voltage frame is sent every 100ms (preferred value, adjustable within the range of 90-110ms), the temperature frame is sent every 200ms (preferred value, adjustable within the range of 190-210ms), and the extreme value state frame is sent every 500ms (preferred value, adjustable within the range of 480-520ms).

[0055] The FreeRTOS real-time operating system utilizes a task hierarchical scheduling mechanism to stagger the transmission times of different types of messages. While a certain type of message is being transmitted, other types of messages enter a waiting queue, avoiding bus conflicts and congestion caused by the simultaneous transmission of multiple frames of data.

[0056] Step 7: Send Status Monitoring and Fault Tolerance Handling After each frame of data is sent, the sending status is monitored in real time: If a single CAN transmission is successful, then proceed to prepare for the transmission of the next frame of data; If a single CAN transmission fails, the retransmission mechanism is automatically triggered, with a maximum of 3 retransmissions (preferred value, adjustable within the range of 2 to 4 times). For abnormal data frames that fail to be retransmitted, fixed-value abnormal padding is performed, and an abnormal status identifier is added to the data frame so that the receiving end can identify it. A CRC checksum is added to all data frames before they are sent. The receiving end uses the checksum to identify whether the data has been transmitted incorrectly, thus further ensuring the accuracy and integrity of the data.

[0057] Step 8: Collaborate testing with the charge / discharge test cabinet EOL test data is automatically transmitted to the charge / discharge test cabinet via a dedicated CAN1 channel. After receiving voltage, temperature, and extreme state frames, the charge / discharge test cabinet, combined with its own charge / discharge control logic, completes the entire process of lithium battery factory performance testing. The entire process requires no manual intervention, achieving fully automated EOL testing.

[0058] IV. Specific Implementation Methods This invention selects three actual engineering conditions of lithium battery packs—low string, standard string, and high string—as implementation cases. Typical parameters are selected for the upper and lower limits of the cycle, the boundary of the number of cells, and the range of recharge times, respectively, to verify the adaptability and stability of the solution under different product specifications and different field electromagnetic environments.

[0059] Example 1 (Intermediate Standard Operating Condition): 12 battery cells in series, with each parameter taken as the optimal intermediate value. The data acquisition baseline period is 50ms, the voltage frame transmission period is 100ms, the temperature frame transmission period is 200ms, the extreme state frame transmission period is 500ms, and the maximum number of message retransmissions is 3.

[0060] SPI completes full data acquisition of 12 battery cells every 50ms, and performs maximum / minimum value calculation after removing out-of-range abnormal data. Voltage data is split into 12 ÷ 3 = 4 frames. The first three frames are filled with 3 valid data points each, and the fourth frame is filled with no empty data points (all 3 valid data points are filled). Temperature data is split into 2 frames for 12 measurement points, with 6 valid data points in each frame. Both frames are fully loaded.

[0061] Voltage frames, temperature frames, and status frames are sent via CAN1 channel in a staggered timing sequence. After the EOL (End-of-Life) command is issued, only the running status of the EOL task is changed; high-priority logic such as overvoltage and overtemperature fault detection and fuse tripping remains unaffected throughout the process. After 72 hours of continuous production line testing, the packet loss rate is <0.05%, making it compatible with standard PACK factory EOL testing.

[0062] Example 2 (lower limit parameter condition): 8 cells in series, each parameter is taken as the lower limit of the range. The acquisition period is 49ms (50ms standard lower limit), the voltage period is 90ms, the temperature period is 190ms, the status frame period is 480ms, and the number of retransmissions is set to 2.

[0063] The voltage of the 8 battery cells is divided into 3 frames: the first two frames each have 3 valid data, the third frame has 2 remaining valid data, and the remaining 1 position is filled with 0xFFFF; the 8 temperature channels only occupy the first 6 points in the 2 frames and the first 2 points in the second frame, and the remaining bytes are filled with 0xFF.

[0064] It simulates a mild electromagnetic interference environment in a workshop, relies on a maximum of two retransmission mechanisms to replenish occasionally lost messages, keeps the bus load below 10%, and has no congestion or jamming. It is suitable for sampling and testing of small-capacity short-string battery samples.

[0065] Example 3 (Parameter Upper Limit Condition): 96 battery cells in series, with each parameter taken at the upper limit of the range. The acquisition period is 51ms, the voltage frame transmission period is 110ms, the temperature frame transmission period is 210ms, the status frame transmission period is 520ms, and the number of retransmissions is set to 4.

[0066] The voltage data of 96 battery cells is divided into 32 frames, with 3 valid data points per frame and no redundancy padding; the temperature data of 96 channels is divided into 16 frames, with 6 valid data points per frame and no redundancy padding. Large batches of messages are distributed in a staggered, time-sharing manner, keeping the peak load on the bus below 30%.

[0067] Simulating strong electromagnetic interference conditions in a workshop, a four-times re-transmission mechanism ensures data integrity under extreme interference. Five consecutive days of uninterrupted aging tests, dozens of EOL start-stop switching cycles, and no abnormal triggering of the system's fault protection logic, making it suitable for mass production lines of high-capacity multi-string power batteries.

[0068] Compared with existing technologies, this invention relies on the AT32F403A main control chip and the FreeRTOS real-time operating system to build a hardware and software platform. Through dual CAN hardware channel partitioning, hierarchical task scheduling, fixed-length data packetization, time-sharing peak transmission, and multiple fault tolerance checks, it solves the technical problems of existing EOL test communication interference, message congestion, low automation, and data loss. It realizes fully automatic, highly reliable, and interference-free transmission of EOL test data, significantly improving the efficiency, stability, and data integrity of end-of-line testing of lithium battery production lines.

[0069] The advantages and positive effects of this invention are as follows: Communication isolation: Physical isolation between test data uplink and business data downlink is achieved through dual independent CAN channels, fundamentally avoiding mutual interference between data streams and ensuring communication stability.

[0070] System safety: An independent EOL test operation mode is constructed, and the start and stop are controlled separately through external commands without interfering with the core safety functions of the BMS (overvoltage protection, overtemperature protection, fault detection, etc.), ensuring the safe operation of the battery management system during the test.

[0071] Bus efficiency: Through fixed-length packetization, cyclic framing and off-peak periodic scheduling mechanisms, CAN bus conflicts and congestion are effectively avoided. Even in a large data scenario with 96 battery cells, the bus load can still be controlled within 30%.

[0072] Data reliability: Through multiple fault-tolerance measures such as resending mechanism, anomaly filling, and CRC check, the integrity and accuracy of EOL test data are guaranteed, with a packet loss rate of <0.05%.

[0073] Automation level: It realizes the fully automatic collection, processing and transmission of EOL test data, and works in conjunction with the charge and discharge test cabinet to complete the factory performance test without manual intervention, which greatly improves production efficiency.

[0074] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or equivalent variations to the disclosed technical content and apply them to other fields. However, any simple modifications, equivalent variations, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood through specific circumstances.

Claims

1. A method for automatically transmitting EOL test data of lithium batteries, characterized in that: Includes the following steps: S101: The main control unit acquires the cell voltage and temperature measurement signals of the lithium battery pack under test, and completes data preprocessing and verification. S102: Based on the dual CAN independent channel architecture, a dedicated EOL test data uplink channel and a normal business data downlink channel are configured to achieve physical isolation and independent operation of the two communication channels. The dual CAN independent channel architecture includes two physically independent CAN controller channels. S103: Build an independent EOL test operation mode and start the automatic external transmission process of EOL test data without interfering with the core safety functions of the battery management system; S104: Performs fixed-length packetization and cyclic framing on the collected cell voltage and temperature data to generate standard data frames that conform to the CAN bus protocol; S105: Employs a multi-type message staggered periodic scheduling mechanism to send different types of data frames in a time-division and orderly manner, avoiding bus conflicts and congestion; S106: Based on multiple fault-tolerance mechanisms such as data resending, anomaly filling, and status identification, the integrity and accuracy of EOL test data transmission are guaranteed; S107: Automatically transmits EOL test data to the charge / discharge test cabinet, collaboratively completing the entire process of lithium battery factory performance testing.

2. The method for automatically transmitting lithium battery EOL test data according to claim 1, characterized in that: The dual CAN independent channel architecture includes: configuring two on-chip CAN controllers, wherein the first CAN channel is dedicated to the uplink transmission of EOL test data, and the second CAN channel is used for downlink reception of normal service messages from the battery pack. The physical links of the two channels are independent of each other, isolating the data streams at the hardware level to avoid resource contention and communication interference between service data and test data.

3. The method for automatically transmitting lithium battery EOL test data according to claim 1, characterized in that: The process involves dividing the collected cell voltage and temperature data into fixed-length packets and cyclically framing them to generate standard data frames conforming to the CAN bus protocol. This includes: a single voltage message containing valid data for 3 cells, with empty bytes filled with a first preset identifier value; a single temperature message containing valid data for 6 cells, with empty bytes filled with a second preset identifier value; and cyclically numbering and framing all data according to the cell serial number order to ensure that each frame has a fixed length, uniform format, and complies with the CAN bus transmission standard.

4. The method for automatically transmitting lithium battery EOL test data according to claim 1, characterized in that: The multi-type message staggered period scheduling mechanism is adopted to send different types of data frames in a time-division and orderly manner, including: setting the basic acquisition period to 50ms; setting the voltage message sending period to 90-110ms; setting the temperature message sending period to 190-210ms; and setting the extreme value state frame sending period to 480-520ms. Through the task hierarchical scheduling of the real-time operating system, the sending time of different types of messages is staggered to avoid bus conflicts caused by the simultaneous sending of multiple frames of data at the same time.

5. The method for automatically transmitting lithium battery EOL test data according to claim 1, characterized in that: The multi-fault tolerance mechanism based on data retransmission, anomaly filling, and status identification ensures the integrity and accuracy of EOL test data transmission. This includes: automatically triggering a retransmission mechanism when a single CAN transmission fails, with the number of retransmissions set to 2 to 4; performing fixed-value anomaly filling on abnormal data frames that fail to be retransmitted, and adding an anomaly status identification to the data frame; and adding a CRC checksum to all data frames, with the receiving end identifying whether the data transmission is incorrect through the checksum.

6. The method for automatically transmitting lithium battery EOL test data according to claim 1, characterized in that: The data preprocessing and verification include: filtering and range verification of the collected raw data, removing abnormal values ​​that exceed the range; and calculating the maximum voltage, minimum voltage, average voltage, maximum temperature, minimum temperature, average temperature, and cell number corresponding to the extreme values ​​for the entire package of cells.

7. The method for automatically transmitting lithium battery EOL test data according to claim 1, characterized in that: The independent EOL test operation mode enables or disables the EOL data transmission function independently via external serial port commands or CAN commands. The start / stop actions do not alter the conventional data acquisition logic and fault judgment logic of the battery management system.

8. An automatic external transmission system for lithium battery EOL test data based on dual CAN independent channels, characterized in that, include: The data acquisition module is used to acquire the cell voltage and temperature measurement signals of the lithium battery pack under test through the main control unit, and to complete the data preprocessing and verification. The channel configuration module is used to configure a dedicated EOL test data uplink channel and a normal business data downlink channel based on the dual CAN independent channel architecture, so as to achieve physical isolation and independent operation of the two communication channels; The mode control module is used to build an independent EOL test operation mode and start the automatic external transmission process of EOL test data without interfering with the core safety functions of the battery management system. The data framing module is used to perform fixed-length packetization and cyclic framing of the collected cell voltage and temperature data to generate standard data frames that conform to the CAN bus protocol. The scheduling and sending module is used to employ a multi-type message staggered periodic scheduling mechanism to send different types of data frames in a time-division and orderly manner, thereby avoiding bus conflicts and congestion. The fault tolerance verification module is used to ensure the integrity and accuracy of EOL test data transmission based on multiple fault tolerance mechanisms such as data resending, anomaly filling, and status identification. The collaborative testing module is used to automatically send EOL test data to the charge and discharge test cabinet, collaboratively completing the entire process of lithium battery factory performance testing.

9. The system according to claim 8, characterized in that, The dual CAN independent channel architecture includes: two CAN controllers configured inside the main control unit, wherein the first CAN channel is dedicated to the uplink transmission of EOL test data, and the second CAN channel is used for downlink reception of normal service messages from the battery pack. The physical links of the two channels are independent of each other. The data framing module includes: a voltage framing unit, used to packetize the cell voltage data into frames of 3 voltage values, with empty bytes filled with 0xFFFF; a temperature framing unit, used to packetize the cell temperature data into frames of 6 temperature values, with empty bytes filled with 0xFF; and a cyclic numbering unit, used to cyclically number and frame all data according to the cell serial number order. The scheduling and sending module includes: a period configuration unit, used to configure the basic acquisition period as 50ms, the voltage message sending period as 90-110ms, the temperature message sending period as 190-210ms, and the extreme value state frame sending period as 480-520ms; and a task scheduling unit, used to stagger the sending times of different types of messages through task hierarchical scheduling of the real-time operating system. The fault tolerance verification module includes: a retransmission unit, which automatically triggers a retransmission mechanism when a single CAN transmission fails, and the number of retransmissions is 2 to 4; an anomaly filling unit, which fills the anomaly data frame with a fixed value; a status identification unit, which adds an anomaly status identification to the anomaly data frame; and a verification unit, which adds a CRC check code to all data frames.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method as described in any one of claims 1 to 7.

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