Battery startup Our Next Energy secured $300M in funding through its Series B round.  The firm intends to use the incoming funds to accelerate the construction of its lithium-iron-phosphate battery gigafactory, which is estimated to cost $1.6B to build.  Our Next Energy was valued at $1.2B post money at the funding round.  The gigafactory will have an initial production capacity of two gigawatt-hours, which will be scaled up to 20 gigawatt-hours over the next three years.  Fifth Wall and Franklin Templeton led the Series B round, with participation from Temasek, Coatue, Riverstone Holdings, Breakthrough Energy Ventures, BMW i Ventures, and others.  The current round is 12 times bigger than the firm's $12M Series A round and almost 4.5 times larger than the $65M Series A1 round.   Our Next Energy received $220M in grants from the state of Michigan, where the factory will be located.