In high-C rate discharge applications such as UAVs, heavy-duty RC models, and jump starters, lithium polymer batteries demand stringent internal resistance (IR) and thermal management. During the cell assembly phase, two primary electrode arrangement methods are utilized: Winding and Stacking. These distinct structural approaches directly dictate the final electrochemical performance and long-term cyclic stability under high-current loads.

Winding Technology: High Efficiency and Internal Resistance Challenges

The winding process utilizes automated winding machines to continuously wind the cathode, anode, and separator into an elliptical or flattened cylindrical shape. Its key technical attributes include:

Manufacturing Advantages: It offers a highly automated production line with throughputs typically exceeding 30 ppm (pieces per minute). The highly mature process relies on advanced tension control systems to ensure cell-to-cell consistency.

High-Rate Disadvantages: The wound structure induces stress concentration at the corner bends. During continuous discharge at rates exceeding 30C, the limited number of current collector tabs extends the electron transport path, resulting in higher internal resistance (IR). Furthermore, uneven temperature gradients at the bends elevate the risk of localized thermal runaway under high-load conditions.

Stacking Technology: The Physical Foundation for High-Rate Performance

The stacking process involves die-cutting the cathode and anode into separate individual plates, which are then alternately stacked with a continuous Z-fold separator.

Structural Benefits: Stacking enables a multi-tab parallel connection, significantly shortening the electron transport distance. Consequently, heat generation at the tabs is substantially reduced during 50C to 100C pulse discharge cycles.

Electrochemical Performance: The electrode plates remain completely flat throughout their lifespan. During phase transitions induced by charging and discharging, lithium-ion insertion and extraction remain uniform across the layered structure. This suppresses lithium plating caused by uneven mechanical stress, thereby enhancing the cycle life of high-rate cells.

Process Limitations: Stacking equipment requires strict management of cutter wear and alignment tolerances (typically ≤±0.1mm). Due to the complexity of the process, production efficiency remains relatively low, and yield rates are highly sensitive to edge burr control.

Conclusion and Industry Segmentation:

Industrial applications indicate that for conventional energy storage or consumer electronics batteries discharging between 1C and 10C, winding technology dominates due to its high throughput and cost efficiency. However, in the realm of industrial-grade high-C rate lithium polymer batteries exceeding 25C, stacking technology is becoming the technical benchmark for ensuring system safety and power consistency, driven by its inherently low internal resistance and thermal impedance.