The square battery winding machine is one of the core equipment in the production process of lithium batteries. Its function is to precisely stack the positive and negative electrode pieces with the separator and wind them into a battery cell. The stable operation of this device is directly related to the performance and safety of the battery. The following are the key details to pay attention to when using:
1、 Preparation before startup
1. Environmental and material inspection
-Ensure that the work area is dry and dust-free, with temperature controlled at 25 ± 5 ℃ and humidity<60%, to avoid the risk of short circuit caused by moisture absorption of the pole pieces.
-Verify that the specifications (thickness, width) of the polarizer and diaphragm are consistent with the process sheet, and that the cut polarizer ears are flat and free of burrs.
-Confirm that the tension arm of the retractable reel is in its initial position, and conduct a 1-minute no-load trial run to observe if the mechanical action is smooth.
2. Mold installation and alignment
-Select a matching hard alloy mold according to the battery model, and calibrate the mold inner diameter tolerance with a micrometer during installation to be ≤ 0.02mm.
-Adjust the position of the correction sensor to ensure that the deviation between the edge of the polarizer and the centerline of the mold does not exceed 0.1mm, in order to prevent winding deviation.
2、 Core operation parameter settings
1. Tension control system
-The initial tension is set to 3-5N · m (adjusted according to the thickness of the substrate), using a taper decreasing mode to avoid subsequent deformation caused by the initial layer being too tight.
-Real time monitoring of tension fluctuations, triggering an alarm immediately and automatically reducing speed compensation if it exceeds ± 0.5N.
2. Speed and number of turns control
-According to the design capacity, calculate the theoretical number of winding turns (for example, a 7-layer structure requires accurate counting of 49 turns), and set the deceleration interval to start the slow stop program 3 turns in advance.
-It is recommended to control the spindle speed between 80-120rpm. If it is too high, static electricity may adsorb dust, while if it is too low, it will affect production efficiency.
3. Hot pressing composite parameters
-The preheating roller temperature is set to 80-100 ℃ (suitable for water-based adhesives), and the composite pressure is maintained at 0.2-0.3MPa to ensure that the diaphragm and electrode are tightly adhered without bubbles.
3、 Key operational procedures
1. Wearing straps and positioning
-Thread the materials into each layer in the order of "diaphragm at the bottom, negative electrode in the middle, and positive electrode at the top", with the electrode ears facing outward for subsequent welding.
-Manually rotate the needle to complete the first round of pre tightening, confirm that the pole piece is wrinkle free, and then start the automatic cycle.
2. Dynamic monitoring and intervention
-Continuously observe the tightness of the winding during operation, and the ideal state should present a regular pagoda shaped hierarchy.
-Immediately press the emergency stop button when wrinkles are found on the polarizer, go back to the problem point and reorganize before continuing.
3. Closing and Unloading
-Leave a 5-8cm redundant length at the end for attaching termination tape, and control the temperature of the hot melt glue gun at 160-180 ℃ to prevent scalding of the polarizer.
-Handle the finished battery cells gently and place them vertically in an anti-static tray to avoid deformation caused by compression.
4、 Exception handling and maintenance
1. Typical fault response
-Broken belt shutdown: Check for particle scratches on the surface of the raw material, replace the guide wheel ceramic ring, and clean the debris.
-Concentricity out of tolerance: recalibrate the servo motor encoder and replace worn rubber rollers if necessary.
-Hi Pot test failure: Focus on checking for micro holes in the ear welding area and adjusting the energy output of the ultrasonic welding head.
2. Daily maintenance standards
-Clean the residual adhesive particles on the vacuum adsorption table daily, and add food grade lubricating oil to the guide rail every week.
-Verify the accuracy of the tension sensor monthly and replace vulnerable parts (such as graphite guide blocks) quarterly.
5、 Safety and Quality Control
-Operators must wear anti-static clothing and insulated gloves, and it is strictly prohibited to wear metal jewelry in contact with equipment.
-Each batch needs to undergo X-ray testing, with a focus on checking the internal layer gaps (standard ≤ 0.05mm).
-Establish SPC control chart, track the CV value of winding density (target<3%), and trace process parameters in a timely manner for abnormal fluctuations.
By strictly implementing the above details, the yield rate of square battery winding can be effectively improved to over 99.5%, laying the foundation for subsequent liquid injection and packaging processes. Equipment management personnel should develop standardized operation manuals and achieve full process quality traceability through video surveillance systems.