But it surely affects LiIons and LiPolys which i think are banned for good reason from aircrafts (at least i think)..
If individual cells get unbalanced in voltage charge, one cell will be charging the other, until the other reaches more voltage and then the process reverses (not the polarity in this case), this causes the battery to get very very hot even when its not connected to anything on the aircraft.
I don't know of a case where this causes a critical temperature, but it surely is a factor for a batt temp light, and i don't know how much or how critical.
Another thing that might happen is your regulator goes bad and starts charging the battery to much, in this case turning off the batt switch will fix it, provided that the batt relay works and disconects from the charging bus, if this does not work... YOU HAVE to turn of your generator, and if the gen relay is not working.. Well.. It was not your day to fly
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From here on, i only write my opinion and what i think is the best to do.
Any how, in the b206, you have two lights, one yellow and one red (battery temp, battery hot). If you get a battery temp, you can turn off the batt switch, look for a nice good safe place to land and while you are going there wait to see if the light stinguishes, if it does not then continue to make your pattern and land to investigate (even though the manual does not require this, i think its smart, its like a midium point of land as soon as possible and land as soon as practicable, like looking for a good spot, safe and close to a place to call for help, although it might not be an airport). if i remember well the manual states, turn of bat switch and land as soon as practicable, and if the light stinguishes you are allowed to turn on the batt switch again (not 100% sure now).
If while you are flying along with the yellow light on, and suddenlty get a red light on, (battery hot), then i will look for the closest place to land safely (not the sweetest place but if it fits i am landing there), shut the generator switch off while landing or as soon as i get the light, and after touchdown. Shut the heli down and..... run forest run!!!.... After an hour of so of no explosion, THEN go back and remove the batt from the heli and try to investigate... I believe that the first thing is your life and carrying an object that might explode its like carring a bomb that might go BOOM at any minute.
Any way this is only my opinion