The official safety data sheet notes that the NCR21700T has a thermal runaway threshold starting around 120°C–130°C (248°F–266°F).
If you exceed 35A (say, a dead short or a mod malfunction pushing 50A), the internal separator melts. This causes an internal short circuit. That heat, combined with the NCA chemistry, leads to "venting with flame." panasonic ncr21700t datasheet hot
Practical takeaway: If your device feels "too hot to hold" (approx. 55°C), the cell is already past its comfort zone. The datasheet "hot" rating is for engineering tolerance, not for human comfort. The official safety data sheet notes that the
The Panasonic NCR21700T represents a critical evolution in cylindrical lithium-ion battery technology, bridging the gap between high-capacity energy cells (like the NCR18650B) and ultra-high-drain power cells (like the Samsung 40T). While often overshadowed by its "G" variant (the Tesla-optimized 21700), the NCR21700T holds a distinct position for applications requiring a balanced current output with moderate thermal generation. This essay analyzes the datasheet characteristics that render the NCR21700T "hot"—not in the sense of thermal runaway, but as a high-performing, warm-running power source under sustained load. If your NCR21700T consistently runs hot, you are
Heat increases resistance, which increases voltage drop. Under a 30A load, the 4.2V cell drops to 3.2V instantly. The device thinks the battery is dead (low voltage cut-off triggers), so it shuts down. You pull the battery out, it measures 3.8V, but it is scorching hot. Solution: Lower your load or use a lower-resistance cell like the Molicel P45B.
The datasheet boasts 500 cycles to 70% capacity. That is a lie if you run it hot. Look at the fine print: Cycle life tested at 0.5C (roughly 2.2A) at 25°C.
If your NCR21700T consistently runs hot, you are effectively killing the cell after three months of daily use.