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I'm building a compact portable console that is going to use a 500ma charger board from Adafruit and possibly a 5v 1a boost as well. Past experience has taught me the chips on those little circuit boards can get quite toasty.

There is not a lot of clearance in my current design between the top of the breakout boards and the flat underside of the polymer battery.

What would you recommend for clearance between the two?

Alternatively, is there a way I could implement some sort of nonconductive barrier to prevent them from touching and exchanging heat?

Thank you in advance, I've done mods before but this is my first time playing with case design.

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    \$\begingroup\$ I think this question is misguided. Unlike electrical insulation, a thermally insulative barrier would just result in the heat accumulating and eventually making it past the barrier anyways unless you have it somewhere else to go. \$\endgroup\$ – DKNguyen Jul 26 '20 at 3:56
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    \$\begingroup\$ Polymer batteries can expand over their lifetime. Probably if you have one mm you will be OK. I think it would be OK to put a small foam pad between the hot IC and the battery, but my assumption there is that the hot IC is going to be dissipating its heat mostly through the PCB. Not my intention to disagree with @DKNguyen. The heat does have to go somewhere. But a small insulation barrier might still be feasible to protect the battery from the high peak temperatures of the hot IC cases. \$\endgroup\$ – mkeith Jul 26 '20 at 4:37
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You have 2 problems. Mount a heat-sink on the charger IC using thermal double-sided tape.

Then insert a GP04 red fiberglass insulator between the charger and battery. It can be as thin as 1/16th inch. In surge devices it is also used as a "blast" shield to stop debris from exploding MOV's. Hopefully this will never be an issue for you.

So as in comments you have heat to dissipate instead of trapping it close to the battery. Then the GP04 insulation helps block heat transfer to the battery, and protects the battery from mild impacts. GP04 can tolerate the heat from a damaged Li-Po battery, but the fumes from a burning Li-Po battery are corrosive.

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  • \$\begingroup\$ Any idea where I could source that material? \$\endgroup\$ – Nareik Seivad Jul 26 '20 at 19:25
  • \$\begingroup\$ Also, someone suggested the PBC might be dissipating some of the heat, do you think it might be effective to mount a thermal pad and heatsink beneath the PCB with the thermal barrier you suggested over the top? \$\endgroup\$ – Nareik Seivad Jul 26 '20 at 19:39
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    \$\begingroup\$ McMaster-Carr is one source. It can be sawed or cut with heavy shears. \$\endgroup\$ – user105652 Jul 26 '20 at 20:04
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    \$\begingroup\$ The heatsinks works best if mounted to the part that gets hot. It can be bottom mounted if that part of the board is a heat conductor. \$\endgroup\$ – user105652 Jul 26 '20 at 20:08
  • \$\begingroup\$ Thank you so much, this really helps. \$\endgroup\$ – Nareik Seivad Jul 27 '20 at 5:44

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