Lithium battery thermal pressure short circuit parameter acquisition method and system

Abstract

The application provides a lithium battery hot-pressing short-circuit parameter acquisition method, and belongs to the field of lithium battery manufacturing. When a cylinder is in place, a PLC controller detects a cylinder in-place signal and sends a start instruction signal. When the start instruction signal is detected, an upper computer sends a trigger signal to a code scanning gun. The code scanning gun scans the bar code of the battery cell and sends the bar code to the upper computer for storage. After the battery cell is scanned, the battery cell enters a hot-pressing test area. The PLC controller sends a hot-pressing start signal to the upper computer and a hot presser. The hot presser works, and a short-circuit tester starts testing short-circuit parameters. The upper computer sends a data reading signal to the short-circuit tester at a set time interval. The short-circuit tester sends the short-circuit parameters to the upper computer until the hot pressing is completed. The upper computer binds the short-circuit parameters with the bar code of the corresponding battery cell to obtain bound time series data. The upper computer stores the bound time series data after compression. The application also provides an acquisition system and improves the short-circuit parameter acquisition accuracy.

Description

Technical Field

[0001] This invention relates to the field of lithium battery manufacturing technology, and in particular to a method and system for acquiring thermal short-circuit parameters of lithium batteries. Background Technology

[0002] Hot pressing is a critical process in lithium battery manufacturing. It involves bonding positive and negative electrodes, separators, and other materials under high temperature and pressure to ensure a tight cell structure and stable performance. Abnormal situations may occur during hot pressing, necessitating the collection of hot pressing short-circuit parameters. However, older production lines still primarily rely on manual collection of these parameters, resulting in low efficiency and high error rates. Some production lines collect short-circuit parameters in real-time using sensors at the end of hot pressing, but this method has significant limitations.

[0003] (1) The short-circuit parameters are only obtained after hot pressing is completed, which cannot reflect the dynamic changes and instantaneous anomalies generated during hot pressing, resulting in the anomalies not being detected and dealt with in a timely manner; (2) The data acquisition is concentrated at the hot pressing end node. The control equipment is prone to communication interruption or buffer overflow under high load or abnormal working conditions, which poses a risk of data loss. (3) Existing solutions mostly adopt synchronous acquisition mode, which occupies PLC communication resources, easily causes communication blockage, and has poor system stability. In actual production, the downtime rate can reach 8%, and the system stability is poor. (4) The original data volume of the short circuit parameters of a single cell is about 2KB. Under high frequency acquisition and transmission conditions, it occupies about 90% of the network bandwidth, resulting in high transmission pressure and complexity, which further restricts the real-time performance and reliability of the data acquisition system.

[0004] In the prior art, the Chinese invention patent application CN113477813A, entitled "A Hot and Cold Pressing Wire for Soft-Pack Lithium-ion Battery Cell Pack", integrates a short-circuit test NG mechanism to collect hot-pressing short-circuit parameters. However, this method collects short-circuit parameters at the end of hot pressing and cannot monitor short-circuit parameters in real time during the hot pressing process, resulting in insufficient collection accuracy. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to solve the problem of insufficient accuracy in the existing methods for acquiring lithium battery thermal short-circuit parameters.

[0006] This invention solves the above-mentioned technical problems through the following technical solution: a method for collecting short-circuit parameters of lithium battery hot-pressing, comprising: the battery cell enters the cylinder detection area upon entering the line; when the PLC controller detects the cylinder positioning signal, it sends a start command signal; when the host computer detects the start command signal, it sends a trigger signal to the barcode scanner; the barcode scanner scans the barcode of the battery cell and sends the barcode data to the host computer for storage; after the battery cell completes the barcode scanning, it enters the hot-pressing test area; the PLC controller sends a hot-pressing start signal to the host computer and the hot-pressing machine respectively; the hot-pressing machine starts working; simultaneously, the short-circuit tester starts testing the short-circuit parameters of the battery cell; the host computer sends a data reading signal to the short-circuit tester at set intervals; the short-circuit tester sends the short-circuit parameters to the host computer until the battery cell completes the hot-pressing; the host computer binds the short-circuit parameters with the corresponding battery cell barcode to obtain bound time-series data; the host computer compresses and stores the bound time-series data.

[0007] This invention uses a host computer to monitor the PLC's start command signal and hot-press start and end signals in real time. When the host computer detects the PLC's start command signal, it indicates that the battery cell has entered the cylinder detection area and is about to enter the hot-press test area. When the battery cell enters the cylinder detection area, the host computer sends a trigger signal to the barcode scanner. The barcode scanner then scans the battery cell's barcode. After scanning, the barcode is sent to the host computer, and the battery cell continues to the hot-press test area. The hot-press machine in the hot-press test area performs hot-press processing on the battery cell. After hot-pressing is completed, the data is sent to the PLC controller. When the host computer detects an abnormal hot-press start signal, it sends a trigger command signal to the short-circuit tester at set intervals after the hot-pressing end signal is sent. The short-circuit tester measures the short-circuit parameters of the battery cell and sends them to the host computer until it receives the PLC end signal. At this point, the host computer binds, compresses, and stores the barcode and short-circuit parameters of the same battery cell, realizing full automation of the process from barcode collection and short-circuit parameter acquisition to data binding. The automated binding process eliminates data omissions or association errors that may occur during manual operation, thereby improving the accuracy of hot-pressing short-circuit parameter acquisition.

[0008] Preferably, the host computer periodically reads the start command signal from the PLC controller. When it detects that the start command signal has changed from FALSE to TRUE, the host computer immediately sends a trigger signal "1" to the barcode scanner to initiate the barcode acquisition operation. After the host computer detects the TRUE signal for the first time, it automatically blocks subsequent continuous TRUE signals and only resends the trigger signal to the barcode scanner when the next non-continuous TRUE signal is detected. This avoids repeated signal triggering that could lead to barcode scanner malfunction.

[0009] Preferably, when sending barcode data to the host computer for storage, the host computer stores the barcode data in a List collection, and the short-circuit test information is stored in a Dictionary as key-value pairs. After the short-circuit parameters are bound to the corresponding cell's barcode, the host computer clears the List collection. Clearing the List collection promptly after the short-circuit test data binding is completed prevents data binding misalignment and ensures the accuracy and consistency of the data collection process.

[0010] Preferably, the host computer periodically reads the abnormal hot-pressing end signal from the PLC controller. When the hot-pressing start signal changes from FALSE to TRUE, the host computer sends a trigger signal to the short-circuit tester at set intervals, storing the read data in the dictionary until the PLC end signal is detected. After the host computer detects the TRUE signal for the first time, it automatically blocks subsequent continuous TRUE signals. Only when the next non-continuous TRUE signal is detected will the host computer resend the trigger signal to the short-circuit tester to perform the next round of short-circuit testing. This avoids repeated signal triggering that could cause the short-circuit tester to malfunction.

[0011] Preferably, the process of compressing the bound time-series data by the host computer includes: By using the transition of the process status word of the PLC controller to the natural boundary, the bound time series data is divided into different data segments, and each data segment is smoothed and filtered to obtain the filtered data segment. Calculate the difference between the data of the next time step and the data of the previous time step in the filtered data segment. If the absolute value of the difference exceeds the difference threshold, the next time step is determined as a process jump point. A jump flag is inserted into the data of the next time step, and the data of the next time step is recorded as the original value after the jump. If the absolute value of the difference is less than or equal to the difference threshold, the difference is mapped to an 8-bit integer range. Based on the process status word of the current data segment, a pre-trained static Huffman code table is selected to compress the current data segment. The compressed data packet includes a header and a payload. The header contains the process status word, the code table ID used, and the lossless original values ​​of key feature values ​​in the data segment. The payload includes the differential sequence encoded using the selected code table, the inserted transition flag, and the original value corresponding to the transition flag.

[0012] This invention first performs differential encoding (calculates Δ value) on the bound time series data, and then applies Huffman coding for compression. The single cell parameters are compressed from 2KB to less than or equal to 1.2KB (compression rate ≥40%), and the network bandwidth usage is reduced to 54% of that of traditional systems. This solves the bottleneck problem of massive data transmission and storage, and significantly reduces data transmission load and storage costs.

[0013] Preferably, the smoothing filtering method for each data segment is to use a Savitzky-Golay smoothing filter with a window length of 5 to smooth each data segment.

[0014] The Savitzky-Golay smoothing filter effectively suppresses high-frequency noise (>100Hz) while preserving the true transition edges of parameters to the maximum extent, providing a clean data source for subsequent differential coding.

[0015] Preferably, the process status words of the PLC controller include: loading status 0x01, hot pressing status 0x02, test trigger status 0x04, and process end status 0x08. This invention uses the transitions of the PLC controller's process status words as natural boundaries to segment the continuous data stream into different logical data segments, ensuring that data within the same segment has similar statistical characteristics.

[0016] Preferably, the short-circuit parameters of the battery cell include the short-circuit state, the first voltage parameter VD1 collected during hot pressing, the second voltage parameter VD2 collected during hot pressing, the low temperature parameter TL collected during hot pressing, the high temperature parameter TH collected during hot pressing, the pressure parameter VP collected during hot pressing, and the hot plate or process temperature parameter TP collected during hot pressing.

[0017] Preferably, the host computer and the barcode scanner communicate via TCP / IP protocol, and the host computer and the short-circuit tester communicate via RS232. The TCP / IP-based communication protocol offers good scalability and adaptability. This invention also provides a lithium battery hot-press short-circuit parameter acquisition system, employing a lithium battery hot-press short-circuit parameter acquisition method. The system further includes a hot press and a first position sensor, a second position sensor, and a third position sensor, each electrically connected to a PLC controller. The first, second, and third position sensors are located at the entrance and exit of the cylinder detection area and the hot-press test area, respectively. The host computer is communicatively connected to the PLC controller, a barcode scanner, and a short-circuit tester. After the battery cell completes the winding process, it sequentially passes through the cylinder detection area, the hot-press test area, and the welding area. The barcode scanner is located in the cylinder detection area, the hot press is located in the hot-press test area, and the short-circuit tester is connected to the battery cell in the hot-press test area.

[0018] The lithium battery thermal short-circuit parameter acquisition system of the present invention adopts a distributed system architecture (host computer - PLC controller - short-circuit tester). The distributed design decouples the acquisition, control and compression tasks, avoiding the occurrence of single point of failure. Attached Figure Description

[0019] Figure 1 A flowchart of the method for collecting lithium battery hot-press short-circuit parameters provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of data transmission in the lithium battery hot-pressure short-circuit parameter acquisition method provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the barcode scanner triggering operation in the lithium battery hot-press short-circuit parameter acquisition method provided in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram illustrating the triggering operation of the short-circuit tester in the lithium battery hot-press short-circuit parameter acquisition method provided in Embodiment 1 of the present invention. Figure 5 This is a flowchart illustrating the compression of bound time-series data by the host computer in the lithium battery thermal short-circuit parameter acquisition method provided in Embodiment 1 of the present invention. Figure 6 This is a schematic diagram of the transmission route of the battery cell in the lithium battery thermal short-circuit parameter acquisition system provided in Embodiment 2 of the present invention; Figure 7 This is a schematic diagram of the working interface of the lithium battery thermal short-circuit parameter acquisition system provided in Embodiment 2 of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] Example 1 like Figure 1 and Figure 2 As shown, this embodiment provides a method for acquiring lithium battery hot-press short-circuit parameters. This method is used to acquire hot-press short-circuit parameters of the battery cells on the hot-press process transmission line. Along the direction of the battery cell transported on the hot-press process transmission line, the battery cell sequentially passes through a cylinder detection area and a hot-press test area. A first position sensor is installed in the cylinder detection area, and a second position sensor and a third position sensor are respectively installed at the entrance and exit of the hot-press test area. The first, second, and third position sensors are electrically connected to a PLC controller. The acquisition method includes the following steps: Step 1: When the battery cell enters the cylinder detection area, the first position sensor sends a cylinder position signal to the PLC controller. When the PLC controller detects the cylinder position signal, it issues a start command signal. When the host computer detects the start command signal, it sends a trigger signal to the barcode scanner. The barcode scanner scans the barcode of the battery cell and sends the barcode data to the host computer for storage.

[0022] Step 2: After the battery cell completes the barcode scanning, it enters the hot-pressing test area. When the second position sensor detects that the battery has reached the hot-pressing area, it sends a hot-pressing completion signal to the PLC controller. When the PLC controller detects the hot-pressing completion signal, it sends a hot-pressing start signal. When the hot-pressing machine receives the hot-pressing start signal, it starts working. At the same time, the short-circuit tester starts testing the short-circuit parameters of the battery cell. After receiving the hot-pressing start signal, the host computer sends a data read signal to the short-circuit tester at set intervals. In this embodiment, the set interval is 20ms. After receiving the data read signal, the short-circuit tester sends the detected short-circuit parameters to the host computer. After the battery cell completes the hot-pressing, it leaves the hot-pressing test area. When the third position sensor detects that the battery has left the hot-pressing area, it sends a hot-pressing completion signal to the PLC controller. When the PLC controller detects the hot-pressing completion signal, it sends a hot-pressing end signal. When the hot-pressing machine receives the hot-pressing end signal, it stops working. At the same time, the short-circuit tester stops testing the short-circuit parameters of the battery cell. When the host computer receives the hot-pressing end signal, it stops sending data read signals to the short-circuit tester.

[0023] Step 3: The host computer binds the short-circuit parameters with the corresponding cell barcodes to obtain the bound time-series data, which is then compressed and stored. The host computer has a built-in database; the collected barcodes are bound to the corresponding short-circuit parameters, and after binding, the data is uploaded to the designated database via an interface for storage and display by the front end.

[0024] This invention employs a distributed system architecture (host computer - PLC controller - short-circuit tester) and a TCP / IP-based communication protocol, exhibiting excellent scalability and adaptability. The distributed design decouples data acquisition, control, and compression tasks, avoiding single points of failure. Simultaneously, the system can operate stably in complex industrial environments with high concurrency and multiple tasks, achieving zero failures during 72 hours of continuous operation testing. The host computer, barcode scanner, short-circuit tester, and PLC controller all utilize existing components. The host computer monitors the PLC controller's status in real time using asynchronous programming technology. The host computer, a type of computer system used for industrial process monitoring and control, can collect real-time data on the operating status and parameters of industrial equipment and remotely operate the equipment by sending control commands. The host computer can be a personal computer (PC) or a host computer. The PLC controller, or programmable logic controller, is a digital control system applied to industrial automation. It effectively controls and manages the operating status of industrial equipment through pre-written programs and logic rules. The barcode scanner is a device used to quickly read barcode or QR code information and is widely used in industrial automated production for data acquisition and traceability. A short-circuit tester is a device used to detect whether there is a short circuit in a circuit. It is commonly used to ensure the safety and reliability of electrical equipment and lines.

[0025] The host computer and the barcode scanner communicate via TCP / IP protocol. When barcode data is sent to the host computer for storage, the host computer stores the barcode data in a List set. After the short-circuit parameter is bound to the corresponding cell's barcode, the host computer clears the List set. The host computer periodically reads the PLC controller's start command signal. (See [link to relevant documentation]). Figure 3 In this invention, the cycle is set to 20ms. When the start command signal is detected to switch from FALSE to TRUE, the host computer immediately sends a trigger signal "1" to the barcode scanner to start the barcode acquisition operation. After the host computer detects the TRUE signal for the first time, it will automatically block the subsequent continuous TRUE signals. Only when the next non-continuous TRUE signal is detected will the trigger signal be resent to the barcode scanner.

[0026] The host computer and the short-circuit tester are connected via RS232 communication. The host computer periodically reads the abnormal thermal pressure start and end signals from the PLC controller at a set interval. See [link / reference needed]. Figure 4 In this invention, the cycle is set to 20ms. When the abnormal hot-pressing end signal is detected to switch from FALSE to TRUE, the host computer sends a trigger command signal to the short-circuit tester. After the host computer detects the TRUE signal for the first time, it will automatically block the subsequent continuous TRUE signals. Only when the next non-continuous TRUE signal is detected will the trigger signal be resent to the short-circuit tester.

[0027] Upon receiving the barcode data, the host computer sends a predefined hexadecimal command signal (such as "0x7B, 0x00, 0x08, 0x02, 0xF0, 0x11, 0x0B, 0x7D") to the short-circuit tester to request short-circuit test data. The test result data returned by the short-circuit tester includes the short-circuit state, the first voltage parameter VD1 collected during hot pressing, the second voltage parameter VD2 collected during hot pressing, the low-temperature parameter TL collected during hot pressing, the high-temperature parameter TH collected during hot pressing, the pressure parameter VP collected during hot pressing, and the hot plate or process temperature parameter TP collected during hot pressing. The host computer binds the received test data with the corresponding cell barcode, using commas as delimiters. After binding, the data is stored in a queue, compressed using the SWAB time-series compression algorithm, and then uploaded to the database for further analysis and processing.

[0028] The process of compressing the bound time-series data by the host computer is an optimization of the standard sliding window compression algorithm, used to resolve the contradiction between the large dynamic range of battery parameters, industrial noise interference, and real-time requirements. See also... Figure 5 The specific compression process includes: Step 3.1: Process-Aware Sequence Segmentation and Noise Filtering Dynamic segmentation: The compressor receives process status words from the PLC (e.g., 0x01 - loading, 0x02 - hot pressing, 0x04 - test triggered, 0x08 - end). The algorithm uses the transitions of the process status words as natural boundaries to segment the continuous data stream into different logical data segments. This ensures that data within the same segment has similar statistical characteristics.

[0029] Adaptive filtering: Before compression, a Savitzky-Golay smoothing filter with a window length of 5 is applied to each data segment. This filter effectively suppresses high-frequency noise (>100Hz) while preserving the true transition edges of parameters to the maximum extent, providing a clean data source for subsequent differential coding.

[0030] Step 3.2: Differential and quantization encoding for short-circuit parameter characteristics First-order difference calculation: For the filtered data segment, calculate the difference Δ between the next time step and the previous time step.

[0031] in, Indicates that within the same logical data segment, the first The value of a short-circuit parameter collected in each sampling period; Indicates and The values ​​of the same short-circuit parameter that are adjacent in time and collected in the previous sampling period; This refers to the sampling sequence number within the data segment. The sampling period is fixedly configured by the PLC or the acquisition system.

[0032] Dynamic range control and quantization: Preset the differential threshold Δ for each parameter (such as VD1, VD2, etc.). max (For example, set to 5% of the range). When |Δ|>Δ max When a process jump occurs, it is identified as a process jump point (e.g., a short circuit occurs). For process jump points, instead of sending their large Δ value to the compression core, a specific "jump flag" is inserted, and the original value after the jump is recorded. The transition flag is a reserved control symbol outside the range of differential encoding values. For example, when using 8-bit differential encoding, it will... Reserved code values ​​or independent control fields outside of 128 to 127 are used as transition markers. Subsequently, the difference sequence from... Then restart.

[0033] For |Δ| ≤ Δ max The normal fluctuation data is mapped to an 8-bit integer range (-128 to 127). This design converts the floating-point Δ sequence with a huge dynamic range into an integer sequence with a concentrated value range that is easy to compress.

[0034] Step 3.3: Hybrid Encoding and Encapsulation Based on Historical Statistics Dual code table design: The system incorporates two pre-trained static Huffman code tables. Code table A (high probability zero value): suitable for the steady phase. Its probability model is trained based on a large amount of data from the "holding pressure" phase. It has extremely short codewords for consecutive "0" or small Δ values ​​close to 0.

[0035] The method for generating code table A (stable phase) includes: collecting historical short-circuit parameter data from multiple batches of hot-pressing processes during the "hot-pressing / holding pressure phase"; performing filtering, differential, and quantization processing on the data; and statistically analyzing the frequency of occurrence of differential values; generating a corresponding static code table using a Huffman coding algorithm based on the statistically obtained probability distribution; and storing the generated code table A in a compressor.

[0036] Code table B (uniform distribution): suitable for the fluctuating phase. Its model is trained based on data from the "test-triggered" phase and has a more uniform distribution of small integers.

[0037] The method for generating code table B (fluctuation phase) includes: collecting historical short-circuit parameter data from multiple batches of hot pressing processes during the "test trigger phase"; performing the same differential and quantization processing on the data; generating another set of static Huffman code tables based on the relatively uniform distribution of differential values ​​in this phase; and storing code table B in a compressor.

[0038] Code table selection: The compressor automatically selects the code table based on the process status word of the current data segment (e.g., code table A is used for "hot pressing" and code table B is used for "test trigger").

[0039] Data Encapsulation: The final compressed data packet consists of a header and a payload. The header contains the process status word, the code table ID used, and the lossless original values ​​of key feature values ​​(such as VP and TP) within the data segment. The payload includes the differential sequence encoded using the selected code table, the inserted "jump flags," and the original values ​​corresponding to the "jump flags."

[0040] This invention first performs differential encoding (calculates Δ value) on the bound time series data, and then applies Huffman coding for compression. The single cell parameters are compressed from 2KB to less than or equal to 1.2KB (compression rate ≥40%), and the network bandwidth usage is reduced to 54% of that of traditional systems. This solves the bottleneck problem of massive data transmission and storage, and significantly reduces data transmission load and storage costs.

[0041] This invention uses a host computer to monitor the PLC's start command signal and hot-press start / end signal in real time. When the host computer detects the PLC's start command signal, it indicates that the battery cell has entered the cylinder detection area and is about to enter the hot-press test area. When the battery cell enters the cylinder detection area, the host computer sends a trigger signal to the barcode scanner, which then scans the battery cell's barcode. The barcode scanner used in this invention is existing technology and has a built-in vision algorithm that can automatically identify the battery cell's barcode with an accuracy of ≥99.9%. After scanning, the barcode scanner sends the battery cell's barcode to the host computer, and the battery cell continues to flow to the hot-press test area. When hot-pressing begins, the hot-press machine sends a hot-press start signal to the PLC controller. When the host computer detects the hot-press start signal, it sends a trigger command signal to the short-circuit tester at set intervals until it detects the PLC's end signal. The short-circuit tester stores the battery cell's short-circuit parameters in a dictionary and sends the short-circuit parameters to the host computer. At this time, the host computer binds and stores the barcode and short-circuit parameters of the same battery cell. It achieves full automation of the entire process from barcode collection and short-circuit parameter acquisition to data binding. By using barcode scanners to replace manual visual identification and using protocol command interaction to replace manual operation, it completely eliminates errors introduced by human intervention, ensures the accuracy of barcode collection, and reduces the collection time per battery cell from 5 minutes required manually to 37.5 seconds, significantly improving the level of automation.

[0042] This invention employs an asynchronous non-blocking architecture to monitor PLC controller signals at a high frequency (20ms cycle). Its mechanism lies in releasing thread resources during I / O wait times through an event loop mechanism (such as async / await), enabling the thread pool to efficiently handle concurrent tasks. This solves the resource blocking problem in synchronous data acquisition, reducing system CPU load by over 42%. Even in high-concurrency scenarios, it maintains millisecond-level response times, significantly improving the overall efficiency of data acquisition and processing.

[0043] Example 2 See Figure 6 This embodiment provides a lithium battery hot-press short-circuit parameter acquisition system, which adopts the lithium battery hot-press short-circuit parameter acquisition method in Embodiment 1. The system also includes a hot press and a first position sensor, a second position sensor, and a third position sensor that are electrically connected to the PLC controller. The first position sensor, the second position sensor, and the third position sensor are located at the entrance and exit of the cylinder detection area and the hot-press test area, respectively. The host computer is communicatively connected to the PLC controller, the barcode scanner, and the short-circuit tester. After the battery cell completes the winding process, it passes through the cylinder detection area, the hot-press test area, and the welding area in sequence. The barcode scanner is located in the cylinder detection area, the hot press is located in the hot-press test area, and the short-circuit tester is connected to the battery cell in the hot-press test area. Figure 6Two detection channels are set up. Each channel is equipped with a hot press and three position sensors electrically connected to the PLC controller. When the cylinder detects a battery cell, it initiates a position adjustment operation and simultaneously sends a signal to trigger a barcode scanner to scan the battery cell's barcode. After scanning, the battery cell is transported to a waiting area to await hot pressing testing. Once two battery cells have completed the barcode scanning operation, the controller controls a robotic arm to grab the battery cells and place them into the hot press, initiating the hot pressing process. The hot press simultaneously performs hot pressing operations on both battery cells. Throughout the hot pressing process, a short-circuit tester polls and reads the short-circuit parameters of the two battery cells every 50-200ms. The host computer simultaneously receives the short-circuit test results from the short-circuit tester. After the hot pressing process is completed, the host computer sends a command signal to the short-circuit tester to read the short-circuit test parameters, and binds cell 1, cell 2, cell 3, and cell 4 to the corresponding short-circuit test parameters. The collected data is compressed by the SWAB time series compression algorithm and uploaded to the database. After the hot pressing is completed, the robot grabs the cells to the production line and enters the next stage of the butterfly welding process.

[0044] When the PLC controller detects the cylinder's position signal, it sends a start command signal. Upon detecting this signal, the host computer sends a trigger signal to the barcode scanner. The scanner scans the barcode on the battery cell and sends the barcode data to the host computer. The host computer receives the barcode data via a socket. After receiving four battery cell barcodes, the battery cell enters the hot press. A short-circuit tester tests the battery cell. Upon successful testing, the host computer binds the battery cell's short-circuit parameters to the barcode, compresses the binding data using a compression algorithm, and stores the result in the database. The host computer's interface caches the battery cell barcode information and the binding data (short-circuit parameters) for each cell in real time. Simultaneously, the host computer writes the short-circuit test process and the binding data for each cell to a background log file for later testing and troubleshooting.

[0045] The host computer software is designed based on asynchronous programming technology. Asynchronous programming relies on tasks or event-loop-based mechanisms (such as async / await). Its advantage lies in the fact that it eliminates the need to explicitly create new threads. Asynchronous operations release threads while waiting for I / O completion, allowing the thread pool to handle other tasks and improving resource utilization efficiency. Especially in I / O-intensive operations such as file reading and writing, network requests, and database queries, asynchronous programming exhibits significant performance advantages. Given the current high frequency of data requests, this invention develops host computer software based on asynchronous programming technology to implement efficient hot-press data acquisition functionality.

[0046] After the program starts, the PLC, barcode scanner, and short-circuit tester are connected sequentially, and the connection status of each device is verified to ensure successful connection before proceeding to the next operation. The host computer monitors the cylinder positioning signal in real time via an asynchronous task. When the cylinder positioning signal is detected, a trigger signal "1" is sent to the barcode scanner. After receiving the signal, the barcode scanner starts barcode acquisition, and the acquired barcode information is stored in a List collection. After the short-circuit test data binding is completed, the List collection is cleared in a timely manner to prevent data binding misalignment and ensure the accuracy and consistency of the acquisition process.

[0047] The system monitors the hot-press reception signal in real time via asynchronous tasks. Upon detecting a hot-press start signal, it immediately sends a command to the short-circuit tester until a short-circuit end signal is received, reading short-circuit test parameters, including short-circuit status, VD1, VD2, TL, TH, VP, and TP data. These parameters are respectively bound to the barcodes of cell 1, cell 2, cell 3, and cell 4 and stored in a queue. When three consecutive short-circuit anomaly data are read, or the amount of short-circuit data collected within a short period exceeds a preset threshold, the system sends an alarm signal to the PLC controller to remind operators to handle the situation promptly and prevent the backlog of short-circuit data from affecting the production process.

[0048] The system initiates asynchronous tasks to monitor the data queue status in real time. When there is data to be processed in the queue, the system will automatically perform a dequeue operation and unbind the dequeueed data. The unbound data will be matched with corresponding barcodes, short-circuit status, VD1, VD2, TL, TH, VP, TP, and other parameters, compressed using the SWAB time series compression algorithm, and then uploaded to the designated database to complete the standardized storage and subsequent processing support of the data. The system is designed with scheduled tasks to monitor the connection status of barcode scanners, PLCs, and short-circuit testers in real time to prevent the data acquisition program from being interrupted due to device disconnection. If a device disconnection is detected, the system will immediately attempt to reconnect to ensure the continuity and stability of the automatic data acquisition program, while avoiding data acquisition failure or production process interruption due to connection interruption. Fast and accurate parameter detection facilitates real-time anomaly detection. For example, setting 3 anomalies to trigger an alarm, and accumulating 10 anomalies to start a production line shutdown; the alarm frequency is reduced by 70%, avoiding unnecessary production stoppages caused by false alarms, and enabling timely detection and handling of product quality issues. While improving production efficiency, the product yield rate is also significantly guaranteed.

[0049] Figure 7 This is an interface diagram of the on-site deployment system. It monitors the detection of two channels separately, records the parameters of the acquisition process, and uploads them to MES after the acquisition is completed by a compression algorithm.

[0050] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for collecting thermal short-circuit parameters of a lithium battery, characterized in that: include: When a battery cell enters the cylinder detection area, the PLC controller sends a start command signal when it detects the cylinder's position signal. Upon detecting the start command signal, the host computer sends a trigger signal to the barcode scanner. The scanner scans the battery cell's barcode and sends the barcode data to the host computer for storage. After scanning, the battery cell enters the hot-pressing test area. The PLC controller sends hot-pressing start signals to both the host computer and the hot-pressing machine, initiating the hot-pressing operation. Simultaneously, the short-circuit tester begins testing the battery cell's short-circuit parameters. The host computer sends a data read signal to the short-circuit tester at set intervals, and the tester sends the short-circuit parameters back to the host computer until the battery cell completes hot-pressing. The host computer then binds the short-circuit parameters to the corresponding battery cell's barcode, obtaining bound time-series data. This bound time-series data is then compressed and stored by the host computer.

2. The method for collecting lithium battery thermal short-circuit parameters according to claim 1, characterized in that: The host computer reads the start command signal of the PLC controller at set intervals. When the start command signal is detected to switch from FALSE to TRUE, the host computer immediately sends a trigger signal "1" to the barcode scanner to start the barcode acquisition operation. After the host computer detects the TRUE signal for the first time, it will automatically block subsequent continuous TRUE signals. It will only resend the trigger signal to the barcode scanner when the next non-continuous TRUE signal is detected.

3. The method for collecting lithium battery thermal short-circuit parameters according to claim 1, characterized in that: When barcode data is sent to the host computer for storage, the host computer stores the barcode data in a List collection. After the short-circuit parameters are bound to the barcodes of the corresponding battery cells, the host computer clears the List collection.

4. The method for collecting lithium battery thermal short-circuit parameters according to claim 1, characterized in that: The host computer reads the abnormal thermal pressure start and end signals of the PLC controller at set intervals. When the thermal pressure start signal is detected to switch from FALSE to TRUE, the host computer sends a trigger command signal to the short circuit tester at set intervals and stores the returned data in the Dictionary until the PLC end signal is received. After the host computer detects the TRUE signal for the first time, it will automatically block the subsequent continuous TRUE signals. It will only resend the trigger signal to the short circuit tester when the next non-continuous TRUE signal is detected.

5. The method for collecting lithium battery thermal short-circuit parameters according to claim 1, characterized in that: The process of compression of the bound time series data by the host computer includes: By using the transition of the process status word of the PLC controller to the natural boundary, the bound time series data is divided into different data segments, and each data segment is smoothed and filtered to obtain the filtered data segment. Calculate the difference between the data of the next time step and the data of the previous time step in the filtered data segment. If the absolute value of the difference exceeds the difference threshold, the next time step is determined as a process jump point. A jump flag is inserted into the data of the next time step, and the data of the next time step is recorded as the original value after the jump. If the absolute value of the difference is less than or equal to the difference threshold, the difference is mapped to an 8-bit integer range. Based on the process status word of the current data segment, a pre-trained static Huffman code table is selected to compress the current data segment. The compressed data packet includes a header and a payload. The header contains the process status word, the code table ID used, and the lossless original values ​​of key feature values ​​in the data segment. The payload includes the differential sequence encoded using the selected code table, the inserted transition flag, and the original value corresponding to the transition flag.

6. The method for collecting lithium battery thermal short-circuit parameters according to claim 5, characterized in that: The smoothing filtering for each data segment is performed using a Savitzky-Golay smoothing filter with a window length of 5.

7. The method for collecting lithium battery thermal short-circuit parameters according to claim 5, characterized in that: The process status words of the PLC controller include: feeding status 0x01, hot pressing status 0x02, test trigger status 0x04, and process end status 0x08.

8. The method for collecting lithium battery thermal short-circuit parameters according to claim 1, characterized in that: The short-circuit parameters of the battery cell include the short-circuit state, the first voltage parameter VD1 collected during hot pressing, the second voltage parameter VD2 collected during hot pressing, the low temperature parameter TL collected during hot pressing, the high temperature parameter TH collected during hot pressing, the pressure parameter VP collected during hot pressing, and the hot plate or process temperature parameter TP collected during hot pressing.

9. The method for collecting lithium battery thermal short-circuit parameters according to claim 1, characterized in that: The host computer and the barcode scanner communicate via TCP / IP protocol, and the host computer and the short circuit tester communicate via RS232.

10. A system for acquiring lithium battery thermal short-circuit parameters, employing the method for acquiring lithium battery thermal short-circuit parameters as described in any one of claims 1-9, characterized in that: The system also includes a hot press and a first position sensor, a second position sensor, and a third position sensor, which are electrically connected to the PLC controller. The first position sensor, the second position sensor, and the third position sensor are located at the entrance and exit of the cylinder detection area and the hot press test area, respectively. The host computer is connected to the PLC controller, the barcode scanner, and the short circuit tester. After the battery cell completes the winding process, it passes through the cylinder detection area, the hot press test area, and the welding area in sequence. The barcode scanner is located in the cylinder detection area, the hot press is located in the hot press test area, and the short circuit tester is connected to the battery cell in the hot press test area.

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