I'm actually fairly convinced that no Dell laptops are immune to ridiculous overheating. I take a TON of them apart for scrap materials, and in the VAST majority of them, the dissimilar metals in the heatsink/heatpipe assemblies are actually fused together - and on the laptops with magnesium or aluminum frames instead of plastic, they're often FUSED TO THE DAMN FRAME (they are NOT supposed to be) - which makes my job a total pain in the ass.
Battery fires, on the other hand, are a rarity as far as I've seen.