Due to its high energy density and discharge capability, it is frequently used in: Electric Vehicles (EVs):
The NCR21700T has a CID (Current Interrupt Device) and a PTC (Positive Temperature Coefficient) thermistor. When the internal temperature hits ~85°C, the PTC increases resistance to stop the current. If you bypass safety circuits, the cell will vent electrolyte. That hot smell is gas escaping. If you hear hissing, throw the device outside immediately. panasonic ncr21700t datasheet hot
It is critical to ensure the cell surface does not exceed 70∘C70 raised to the composed with power C 80∘C80 raised to the composed with power C Due to its high energy density and discharge
While powerful, users should note that these are usually "flat-top" cells and may require specific adapters or spacers for use in standard consumer flashlights. That hot smell is gas escaping