Why do most high-rate batteries choose the stacking process?

     High-rate batteries (such as power batteries, fast-charging batteries, etc.) need to maintain high efficiency, stability and safety during high-current charging and discharging, so they have higher requirements for manufacturing processes. At present, the stacking process is more and more widely used in high-rate batteries, gradually replacing the traditional winding process. So why do high-rate batteries prefer the stacking process?

1. Shorter current path and lower internal resistance

During high-rate charging and discharging, the battery needs to withstand a larger current, and the length of the current path directly affects the internal resistance and heat generation. 

Winding process: The current needs to bypass along the length of the pole piece, and the path is longer, resulting in higher internal resistance, 

and energy loss and heat generation are more obvious under high current.

Stacking process: The positive and negative pole pieces are stacked in parallel, and the current only needs to pass through the thickness of the pole piece vertically. 

The path is shorter, the internal resistance is lower, 

and it is more suitable for high-rate charging and discharging.

2. Higher energy density and better space utilization

The energy density of the battery directly affects the endurance and performance, and the stacking process has more advantages in space utilization. 

Winding process: A cavity will be formed in the center of the battery cell, resulting in space waste and limited energy density.

Lamination process: The pole pieces are neatly stacked, without a central cavity, with higher space utilization and energy density can be increased by 5%-10%.

3. Better mechanical and thermal stability

High-rate batteries will generate large expansion and heat during charging and discharging, and the lamination process can better deal with these problems.

Uniform stress distribution: The lamination structure makes the pole piece evenly stressed, reducing deformation or diaphragm wrinkling caused by uneven expansion.

Better heat dissipation: More uniform heat distribution, avoiding local overheating and improving safety.

4 Longer cycle life

High-rate batteries are prone to accelerated aging during frequent high-current charging and discharging, and the lamination process helps to extend life.

Reducing interface degradation: The lamination structure reduces the shedding of active materials caused by the bending of the pole piece, 

and the cycle life is increased by 10%-20% compared with the winding process.

5. Adapt to large-size and special-shaped battery design

As batteries develop towards large size and customization, the lamination process is more flexible.

Winding process: Large-size batteries are prone to deformation, affecting performance. 

Lamination process: It can be adapted to blade batteries, special-shaped batteries and other designs to meet the needs of different application scenarios.

6. Challenges of lamination process

Although the lamination process has obvious advantages, there are also some challenges: 

Low production efficiency: Lamination requires precise alignment, and the production speed is slower than winding.

High equipment cost: Lamination machines are more complex than winding equipment, and the initial investment is larger.

However, with the development of technologies such as laser cutting and high-speed lamination machines,

 the production efficiency of the lamination process is improving, and its application in high-rate batteries will be further expanded in the future.

Summary: The core reason for high-rate batteries to choose the lamination process is: lower resistance, higher energy density, better stability and longer cycle life. 

Although production efficiency is still a challenge at present, with technological advances, the lamination process will become the mainstream choice for high-rate batteries,

 especially in electric vehicles, high-end energy storage and other fields.