Natural gas fireplace,heater

I have a Kingsman stove in my house and since the fan motor runs bit noisy making it hard to sleep,,I use it without fan running,
which made me wonder if this type of heater could be used in RVs as one wouldn't need electric power to use it..or not very much anyhow,
.I noticed there's a tiny battery inside the thermostat,,I wonder does that gives it spark to start the fire or how does it work?