Mystery mark on battery pack

[John_D]

On a rechargeable battery pack for my camera, I have the traditional + and - in circles identifying their terminals. But there is another mark, a T inside a circle. I've attached a very small photograph.

What does this mean? My google fu is failing me.

 

[Externet]

Probably temperature sensing terminal, to control charge/discharge rate.

 

[(*steve*)]

Yeah, you'll find it is a thermistor connected to the +ve or -ve side of the battery. You will find that the resistance changes as the battery heats up or cools down.

It is normally used when charging as the discharge rate is typically much lower than the charge rate.

 

[Dereklee]

I'm afraid that i dont fully understand.
so, it plays the role in protecting the battery?

 

[(*steve*)]

When charging, the temperature is monitored. If it gets too high (or in some cases too low) the charging is discontinued.

With some battery technologies the temperature (or changes in it) can be an indication of state of charge too.