I opened a bad old cordless NiCad drill battery last week. The battery has three terminals. The tow terminals on the sides are labeled + and - and as expected are connected onto the ends of the series cells of the batteries, but there is another smaller connection which doesn't state anything. Its not used by the drill but by the charger and when opening the battery, a small,thin, rectangular object reading ""Klixon 7-S 4MM45B2-21V Z3J" was on it. I haven't been able to find any datasheets for it.
Could someone tell me what that rectangular thing is and what it is used for? I found a similar one i another NiCad drill battery.
Thanx in advance... Have a great day