Rolling Process of Lithium Battery Electrode Piece

The general process flow of lithium-ion battery electrode piece manufacturing is as follows: the active material, binder and conductive agent are mixed to prepare a slurry, which is then coated on both sides of the copper or aluminum collector. After drying, the solvent is removed to form the electrode piece. The electrode piece particle coating is compacted and densified, and then cut or divided. Rolling is the most commonly used compaction process for lithium battery electrodes. Compared with other processes, rolling not only changes the hole structure of the electrodes, but also affects the distribution of the conductive agent, thus affecting the electrochemical performance of the battery. In order to obtain the optimal hole structure, it is very important to fully understand the rolling compaction process.

Basic process of rolling and pressing

In industrial production, lithium battery pole pieces are usually rolled and compacted continuously with a rolling press machine, by a pair of rollers , as shown in Figure 1. In this process, the pole pieces coated with particle coating on both sides are sent into the gap between the two rollers, and the coating is compacted under the linear load of the rollers. After coming out of the gap, the pole pieces will rebound elastically, resulting in an increase in thickness. Therefore, the roll gap size and rolling load are two important parameters. Generally, the roll gap should be less than the required final thickness of the pole piece, or the load can make the coating compacted. In addition, the rolling speed directly determines the holding time of the load acting on the electrode, also affects the springback of the electrode, and finally affects the coating density and porosity of the electrode.

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