Hannah Sieber knows just how transformative batteries can be. At her previous startup, EcoFlow, she used them to replace generators, whether for powering homes after a bad storm or RVs at a campsite. The experience made her wonder what else batteries could do, especially smaller ones. “What are the other industries that could dramatically change?” she recalled thinking at the time. After leaving EcoFlow, and while studying at Stanford, it hit her. She had been researching how power shutoffs in C...