Why Do High-Rate Batteries Mostly Choose Stacking Technology?

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. Therefore, they have higher requirements for manufacturing processes. Currently, the application of stacking technology in high-rate batteries is becoming more and more widespread and is gradually replacing the traditional winding process. So, why are high-rate batteries more inclined to choose stacking technology?

1 Shorter Current Path and Lower Internal Resistance

During high-rate charging and discharging, batteries need to handle higher currents, and the length of the current path directly affects internal resistance and heat generation.

• Winding Process: The current has to travel along the length of the electrode sheet, resulting in a longer path, higher internal resistance, and more significant energy loss and heat generation under high current.

• Stacking Process: The positive and negative electrode sheets are stacked in parallel, and the current only needs to pass vertically through the thickness of the electrode sheets. This results in a shorter path, lower internal resistance, and is more suitable for high-rate charging and discharging.

2 Higher Energy Density and Better Space Utilization

The energy density of a battery directly affects its range and performance, and the stacking process has a greater advantage in space utilization.

• Winding Process: A cavity is formed in the center of the cell, leading to space waste and limited energy density.

• Stacking Process: The electrode sheets are neatly stacked without a central cavity, resulting in higher space utilization and an energy density increase of 5%-10%.

3 Better Mechanical and Thermal Stability

High-rate batteries generate significant expansion and heat during charging and discharging, and the stacking process can better address these issues.

• Uniform Stress Distribution: The stacked structure allows for even stress distribution on the electrode sheets, reducing deformation or separator creasing caused by uneven expansion.

• Better Heat Dissipation: Heat is distributed more evenly, preventing localized overheating and enhancing safety.

4 Longer Cycle Life

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

• Reduced Interface Degradation: The stacked structure minimizes the shedding of active materials caused by electrode sheet bending, resulting in a 10%-20% increase in cycle life compared to the winding process.

5 Adaptability to Large-Size and Customized Battery Designs

As batteries move towards larger sizes and customization, the stacking process offers greater flexibility.

• Winding Process: Large-size cells are prone to deformation, affecting performance.

• Stacking Process: It can be adapted to blade batteries, customized batteries, and other designs to meet the needs of different application scenarios.

6 Challenges of Stacking Technology

Despite its obvious advantages, the stacking process also presents some challenges:

• Lower Production Efficiency: Stacking requires precise alignment, resulting in slower production speeds compared to winding.

• Higher Equipment Costs: Stacking machines are more complex than winding equipment, leading to higher initial investment.

However, with the development of technologies such as laser cutting and high-speed stackers, the production efficiency of the stacking process is improving, and its application in high-rate batteries will expand further in the future.

Summary

The core reasons for high-rate batteries to choose stacking technology are lower resistance, higher energy density, better stability, and longer cycle life. Although production efficiency remains a challenge at present, with technological progress, the stacking process is expected to become the mainstream choice for high-rate batteries, especially in the fields of electric vehicles and high-end energy storage.