Russia also made one of these as a prototype and it was ~90 mm3 & 0.35 g for ~1 μW of electrical power ( https://newatlas.com/nickel-nuclear-battery-design/5488

Russia also made one of these as a prototype and it was ~90 mm3 & 0.35 g for ~1 μW of electrical power ( https://newatlas.com/nickel-nuclear-battery-design/54884 https://newatlas.com/nickel-nuclear-battery-design/54884 ) So to power a laptop you'd need a really, really, really big & heavy battery. Like, the size of a house big.