Two Sided Tape Thermal Insulation for Sticking Batteries Together?

Yeah. The last time I required a special two sided tape I cut out the middle man and rang Scotch direct, explained what was required and and had it in a couple of days.

The only Scotch two side tape I know about is about 1/64 inch thick and would hardly be called a thermal insulator or a spacer.

If you know of a particular model number of Scotch product that matches to requirements I would be appreciative to know what it is.

As far as battery pack tape is concerned, insulation is not even in the design criteria. They use double sided relatively thick tape because the battery sides are not perfectly flat and smooth. I've used "picture hanging tape", and I've used RTV Silicone. Both work. The RTV is harder to separate down the road. Some packs I've worked on have butyl rubber, like an inner tube, with contact type cement on both sides.

How much space between batteries do you need, or can you tolerate?

There are thin foam pads with adhesive on both sides, maybe 1 or 2 mm thick. They should be available at most hardware stores.

If you are dealing with high temperatures (50°C or higher) you might want to contact a manufacturer's rep for something more suitable. The general purpose stuff might break down over time under such conditions.

Look, what I required was a two sided tape that was oil proof. Scotch was very helpful and provided the product I required. Give them a call, explain what you need and buy it. It's just not that hard.

I really doubt it's anything to do with batteries heating each other -- they both give off the same heat. The pads will just be to take up imperfections in the sides of the batteries and limit movement. They are far to small to generate a space for heat convection.

Batteries only last a few years in these applications anyway. They are handled roughly by the charging circuits (supposedly to ensure they are ready for another discharge cycle really quickly, but I've never understood why that requires continuous overcharging).