At first glance, combining lipo batteries of the same capacity but different shapes into a single pack might seem possible. However, in practice, this is unsafe and unreliable due to the unique characteristics of LiPo cells and how they behave when connected.

⚠️ Inconsistency in Internal Characteristics

Even if two batteries share the same rated capacity (e.g., 2000mAh), their shape, thickness, and internal structure affect resistance, thermal behavior, and discharge profiles. When assembled in a pack, mismatched shapes lead to uneven current distribution, causing one cell to work harder than the other. Over time, this results in imbalanced charging, reduced performance, and shorter lifespan.

🔋 Safety Risks

Lithium polymer batteries are sensitive to overcharging, deep discharging, and thermal stress. When combining different shapes, the cells can heat up at different rates, and their protection circuits may not respond uniformly. This imbalance increases the risks of swelling, leakage, or even thermal runaway, which can be dangerous for both the device and the user.

⚙️ Best Practice – Use Identical Cells

LiPo battery packs should always be built from identical cells in shape, size, capacity, and chemistry to ensure reliability, safety, and long service life. This guarantees consistent electrical behavior, balanced charging cycles, and optimal pack performance.

At LiPol Battery Co., Ltd., we specialize in custom lithium polymer battery pack design. Instead of mixing different shapes, we provide tailored solutions with the exact cell size and configuration your device needs—whether that means increasing capacity or voltage or modifying connectors and protection circuits.

Choosing identical cells ensures safety, efficiency, and long-lasting performance, so assembling different shapes in the same pack is never recommended.