As one of the core processes of lithium battery electrode manufacturing process, battery stacking machine is extremely important in the whole battery cell production process. The battery stacking process requires a high degree of stacking precision, which has a great impact on the quality of the stacked battery cells.

Figure 1. Automatic battery cell electrode stacking machine

At present, the common problems of battery stacking machines in the market include poor electrode alignment, battery separator folding, electrode flipping, electrode dropping, short circuit of stacked electrodes, etc.

Problem 1: Poor alignment of battery electrodes

Before the battery electrode sheet is put into the stacking station, it is easy to cause poor alignment of the electrode sheet due to poor secondary positioning.

To ensure the alignment of the stacked electrodes, a secondary positioning station is essential, and in this configuration an alignment of ±0.3 mm can be achieved.

To further improve the alignment accuracy of the stacked electrodes, a high-precision and highly responsive self-correcting device is required. The CCD vision monitoring system acquires the alignment data between electrode sheet and electrode sheet, electrode sheet and battery separator, and battery separator and battery separator to achieve closed-loop control of the pole position accuracy and achieve a pole alignment of ±0.2mm or even higher accuracy.

Problem 2: Battery separator folds

As the battery separator in the conveying process, the parallelism of the over-rollers exceeds the standard, which will lead to uneven friction of the battery separator on the rollers and run off causing wrinkles.

In addition, the battery separator tension, the real-time response speed of the battery separator cache in the stacking process can also cause battery separator folds.

The over-rollers are machined as a whole to ensure their consistency, thus achieving precise control of over-rollers parallelism.

In addition, the tension control of the battery separator should be done to minimize the tension fluctuation, so as to effectively control the battery separator folds.

Problem 3: Battery tabs fold

During the conveying process of the electrode sheets, the battery tabs are subject to its own gravity and the influence of the electrode sheet wrap angle, which easily leads to the battery tabs folding.

Adding battery tabs guiding mechanism and battery tabs folding detection mechanism during the conveying process of the electrode sheets ensures that the lug is in the required condition when entering the stacking station.

Problem 4: Dropping of electrode sheets

The electrode sheet vacuum suction plate is prone to breakage during the electrode pickup and conveying process, resulting in unstable electrode suction.

By optimizing the internal structure of the vacuum suction plate, the suction force of the suction plate can be enhanced, and the starting time of the suction plate can be shortened to achieve a high-speed and stable suction effect.

Problem 5: Short-circuiting of stacked electrode sheets

The main factors affecting the short circuit of stacked electrode sheets are: dust, debris, poor alignment of electrode sheets, burrs of electrode sheets, etc.

By optimizing the dust control at the battery tabs forming process, electrode sheets cutting process, and the electrode sheets conveying process.

The process dust of the electrode stacking process is controlled by optimizing the design of the dust suction piping and the air volume at the suction port.

In summary, the battery stacking machine needs to do a good job in every detail of the process, in addition to good alignment accuracy, but also to ensure that the electrode sheet and the battery separator no damage and no folding, good process dust control, etc.

WinAck Group can provide complete battery electrode manufacturing process solutions. Come by, contact us for a solution that can help you succeed. For better batteries, Win & Ack!