General Motors is backing a battery startup run by Tesla alumni to sell grid storage, the business where Tesla's Megapack is the giant. GM Ventures led a $108 million Series B round in Peak Energy, a Burlingame, Calif., developer of passively cooled sodium-ion storage systems, Peak announced on Wednesday, Oct. 21, 2026. Maverick Silicon, Infinite Capital, Eclipse, Xora Innovation and LG Technology Ventures also invested.

The key numbers

  • Orders: Peak says it has "over $1 billion" in existing customer orders; Bloomberg put it at about $1.1 billion, mostly a 4.75 GWh deal with Jupiter Power and a 1.5 GWh deal with Energy Vault.
  • Factory: a 4 GWh-a-year plant in Sacramento, Calif., due to start production in the first quarter of 2027, per Peak.
  • Funding: at least $173 million disclosed so far, EV calculated. Neither company disclosed Peak's valuation or GM's share of the round.
  • New market: Peak says the money will help it launch its product for data centers, where it says access to power "has become the primary constraint on growth."

Why sodium-ion, and the GM link

Peak says removing active cooling and scheduled maintenance can cut the cost of energy by up to 20% compared with conventional lithium iron phosphate (LFP) storage. Sodium-ion cells store less energy for their weight, which is why they're aimed at stationary storage rather than cars. GM and Peak announced a partnership in June: GM develops sodium-ion cells in its Michigan labs and keeps manufacturing rights, and Peak integrates them into its systems, according to EV. Peak buys cells from Chinese suppliers for now; "It's already catalyzed in China," CEO Landon Mossburg told Bloomberg.

What it means for Tesla

Peak's founders include Mossburg, who held leadership roles at Tesla, and COO Liam O'Connor, formerly Tesla's VP of global supply management, per EV, and its first sales VP previously led U.S. grid-scale storage sales at Tesla. They're chasing the same data-center buyers Tesla Energy is: Tesla said its storage backlog is at a record, driven partly by data centers, and xAI bought another $269 million of Megapacks this year. Tesla is ramping its own LFP cells and a 50 GWh Megafactory in Texas, a far larger scale than Peak's first plant.