IR Leds to be Driven by Coin cell
The internal resistance of a 2450 coin cell is about 10 Ω when fresh (see https://data.energizer.com/pdfs/cr2450.pdf). If you consumed 300 mA, the voltage would drop by 3 V -- and you wouldn't be able to drive the LEDs.
These cells are not suitable for high continuous currents; they are intended for very low continuous drain (at les than 1 mA), or brief high current pulses.
Although these are rated at over 500 mA.h, this does not mean you can consume at a load of 500 mA for 1 hour -- but you can consume at 1 mA for 500 hours.