GM Leads Peak Energy's $108 Million Round for Sodium-Ion Grid Storage

GM Ventures led a $108 million Series B for Peak Energy, a sodium-ion battery startup, Electrek reported on Oct. 23. General Motors is developing sodium-ion cells with the company, and they are for grid storage, not cars.

Electrek's headline says GM is betting on cells that do not use lithium. The body says something narrower: GM Vice President of Battery and Sustainability Kurt Kelty said "for grid-scale stationary storage, sodium-ion is the right solution", and the article states GM will not develop sodium-ion cells for EVs because their energy density is too low.

The round and what it pays for

Electrek says LG Technology Ventures also took part and that the round was oversubscribed. The money goes to US manufacturing, to filling more than $1 billion in existing customer orders, and to taking Peak's passively cooled systems into data centres.

Peak's plant is the physical constraint. EnergyTech, in an article dated July 10, 2026, describes a 183,000-square-foot facility at Metro Air Park in Sacramento with capacity for up to 4 GWh of battery systems a year, backed by $71 million of capital investment and a $10.5 million CalCompetes tax credit. Peak planned shipments by the first quarter of 2027. Customer commitments stand at 6 GWh, with Jupiter Power, Energy Vault and RWE Americas named.

The denominator matters. Sacramento's 4 GWh a year is smaller than the 6 GWh already committed, so the order book is more than one year of the plant's output even at full rate, and a plant that has not shipped yet is not running at full rate.

What GM actually agreed to in June

The partnership was announced on June 10, 2026. Per Electrek, GM develops the cells in its Michigan battery labs and keeps exclusive manufacturing rights, while Peak builds them into its storage systems. Latitude Media adds that GM planned to start prototyping stationary sodium-ion cells at its Wallace Battery Cell Innovation Center by the end of 2026 and to commercialise them by 2028.

So the $108 million funds Peak's current, first-generation product, while the GM cell is a 2028 target. Peak co-founder and chief commercial officer Cameron Dales said, in Latitude Media's account, that Peak is "kind of where LFP was 10 years ago" on its improvement curve. LFP is lithium iron phosphate, the chemistry that dominates stationary storage today.

Date	Event
Aug. 2024	Peak's $55 million Series A, led by Xora Innovation
Nov. 2025	Jupiter Power agreement, $500 million for 4.75 GWh
Feb. 2026	Energy Vault, 1.5 GWh for data centres
June 10, 2026	GM and Peak partnership announced
End of 2026	GM cell prototyping targeted
Q1 2027	Sacramento shipments planned
2028	GM commercialisation target

The claims nobody has tested

Peak says its passive cooling removes the active cooling equipment LFP systems need, cuts storage costs 20 percent against conventional systems and delivers more than 99 percent uptime. These are the company's figures, relayed by Electrek, and neither article names an independent test. Electrek gives no energy density, cycle life or efficiency number for the cells, and Latitude Media gives none either.

EnergyTech adds two cautions: sodium-ion is reportedly under 1 percent of global EV and storage battery production, and it costs more than lithium-ion for equivalent capacity. A passive-cooling saving of 20 percent has to clear that price gap first.

Peak is pitching data centres, the same power-hungry buyers behind the wafer-scale systems in The Terminal's piece on Cerebras, and power supply is a theme in its report on SpaceNukes and DARPA. What would change this read is a field result: a delivered system with a measured uptime and a measured cost per kilowatt-hour. Peak began field deployments in 2026, and its first Sacramento-built shipments in Q1 2027 are the earliest test.