Thermal Protection for Battery Pack

[rfranzk]

Hi Ante!!!
  I have welded a few battery packs with my capacitive discharge welder and am looking for a source for the pepi thermal fuses, or information on how to configure pptc device to battery pack. The pptc resistance changes with temperature and I am unsure how temperature rises during the charge cycle will affect overall operation.  I have looked hi and lo for sources and have had no luck on the pepi. 

Thanks in Advance.

rfranzk

[ante]

Hi rfranzk,

I think you are referring to a PolySwitch like these: http://www.elfa.se/pdf/60/06027007.pdf
I buy mine at ELFA http://www.elfa.se/en/
They look like this:

[rfranzk]

Hi Ante!!
  Yes it is a polymer positive temperature coefficient switch!! I am curious about using them to protect the batteries of a cordless tool during the charge process. Most battery packs use a thermal circuit breaker that measures battery temperature and cuts off charge current.        http://www.pepiusa.com/  The pptc will change resistance at temperature.
  I am unsure as to whether these can be surface mounted to battery to sense battery temperature or whether they change temperature and resistance based on current flow or resistance to flow?  Also what do I consider when choosing the proper device? 

Thanks for the quick reply

rfranzk

[ante]

Hi rfranzk,

I might have misunderstood you, this is PPTC as you mentioned. These are not supposed to regulate or interrupt the charging process but protect the battery pack from burning up in case of a short circuit or overload condition.
This might be what you are looking for: http://www.elfa.se/elfa-bin/setpage.pl?http://www.elfa.se/elfa-bin/dyndok.pl?lang=en&dok=2009881.htm