Lithium-ion Full Battery Manufacturing Process Training--Rolling

1.Rolling Principle

Roll pressing is a process that utilizes a roll press machine (as shown in Figure 1,the roll press machine used in the industry consists of three core components: a pair of rollers, an unwinding device, and a rewinding device) to compress the thickness of the electrode (as shown in Figure 1). This compression increases the compaction density of the electrode coating, reduces the thickness of the electrode, and ultimately enhances the energy density of the battery.

 

2.Rolling Equipment

Loading Sequence: Loading Device - Correction Device - Edge Trimming Device - Tension Device - Preheater - Rolling Mills - Tension Device - Correction Device - Winding Device

 

3.Rolling Effect

1）Improving Electronic Conductivity：

When the compaction density of a porous electrode is low, there is poor contact between the

particles, resulting in a necessarily high contact resistance. As the compaction density increases,

the contact between the particles becomes tighter, leading to a decrease in contact resistance.

However, once the compaction density reaches a certain range where the contact between

particles has achieved an optimal value, further increasing the compaction density will not affect

the contact resistance.

From the graph, it can be observed that when the compaction density is less than3.8g/cm3, the

sheet resistance gradually decreases as the compaction density increases. Once the compaction

density exceeds 3.8g/cm3, further increasing the compaction density does not significantly affect

the sheet resistance, which remains relatively constant.

 

Note: The following figure illustrates the relationship between the compaction density and resistivity of an electrode made with the formula of LiCoO2: Super P:PVDF = 97.5%: 1.4%: 1.1% (materials sourced from Canrd: www.canrd.com).

2）Improving Electronic Conductivity