Ultra thin temp sensor

[retepsnikrep]

Any reccomendations for an ultra thin temp sensor compatible with the picaxe via I2C or simple ADC thermistor which needs to squeeze between some flat battery cells in a sandwich. I only need a range of about -10 to 100C max.

Ultra small might do if ultra thin is not an option.

Thanks Peter

Think I might have answered my own questions a couple of these should do the trick.

http://www.rapidonline.com/netalogue/specs/61-0430e.pdf

 

[premelec]

wire...

Copper wire has a positive temperature coefficient as does nickel [harder to get] - assuming you want to be clever and cheap just run some skinny magnet wire along side the cells and measure the voltage drop at constant current... an op amp can help to keep the test current low and output voltage high... if you make the wire a tight parallel loop then you get twice the resistance, and good noise cancellation and the average temperature of the wire...

 

[manuka]

"Ultrathin" really relates to the scale- how large are the batteries?! Thermistors are widely available that are about the size of a pinhead if your pack uses AA sized cells.

But (as it's assumed you are monitoring overall pack temperature),why "between the cells" ? If just a modest size pack, then normal thermal conductivity will mean any external sensor will be promptly at much the same temperature. Many cordless drills have long used this approach of course, with a thermal sensor in the docking charger arranged so it touches a exposed part of the inserted NiCd battery pack. Stan

 

[retepsnikrep]

My pack is 50 x 20ah Lifepo4 A123cells in a stack. 3.3kwh capacity. A couple of the ultra thin sensors I found earlier will give me the core temperature so i'm happy enough. Thanks for the other ideas