A Stockholm startup that transforms discarded electric-vehicle batteries into grid-scale storage systems announced Monday that it has closed a $4.6 million seed round, betting that commercial property owners will pay for second-life power solutions even as the price of new lithium cells continues its downward march.
Rebaba said Sistafund led the oversubscribed financing, with backing from EIT Urban Mobility, Rockstart and The Blue Minds Company, according to Tech.eu. The round lifts total funding to approximately $5 million since a SEK 5.5 million (roughly $500,000) pre-seed in late 2024.
The company's pitch is straightforward: retired EV batteries still hold enough capacity to smooth out grid fluctuations and provide backup power, but at a fraction of the carbon cost of manufacturing new cells. A 400-kilowatt-hour installation Rebaba deployed at a Logistea warehouse in Borås avoided more than 40 tons of CO₂ emissions compared to an equivalent new-battery system, the real-estate firm reported in its 2025 sustainability disclosures.
Whether that environmental argument can sustain a business remains an open question. Rebaba competes in a crowded European second-life battery sector alongside Germany's Voltfang, UK-based Connected Energy, Spain's BeePlanet and fellow Swedish outfit Batteryloop. Global battery storage deployments grew roughly 40 percent year-over-year in 2025 to between 108 and 112 gigawatts, the International Energy Agency reported, though the agency cautioned that falling prices for new batteries and rising demand for recycled materials are squeezing the economics of reuse.
Rebaba co-founders Paula Runsten and Felix Kruse, both 28, cut their teeth at Northvolt in Sweden and Tesla in Norway before launching the company in April 2023, according to Swedish company filings. Runsten runs the business as CEO; Kruse handles technology as CTO. Their approach centers on manufacturing battery systems in-house at a facility in Lidingö, then pairing the hardware with a cloud-based monitoring platform that tracks battery health and optimizes participation in ancillary grid services.
"By keeping the complexity within our core technology, we can assemble the rest from standard, locally available components," Kruse told Tech.eu.
The seed capital will go toward scaling production at the Lidingö site to 40 megawatt-hours annually and establishing additional manufacturing hubs outside Sweden. Rebaba has signed distribution and deployment agreements across six European markets, though the company has not disclosed total contracted capacity.
Scandinavian fuel retailer OKQ8 announced a partnership in January to deploy Rebaba's systems at its own sites and resell them to business customers, emphasizing battery-level traceability and modular design. Swedish electrical wholesaler KP Energy began distributing the systems in March. In June, German charging-infrastructure provider Nanuq said it would use Rebaba's storage to overcome grid-connection bottlenecks at electric-truck depots in Germany, Austria and Switzerland. The company also collaborates with Smartports on solar-carport projects in France.
Rebaba participates in a SEK 12.4 million Vinnova-funded research project alongside Stena Recycling, OKQ8, Smartports and RISE that targets 1.2 megawatt-hours of deployed capacity and full lifecycle traceability through eventual recycling.
The financials remain early-stage. Swedish filings show Rebaba generated SEK 1.8 million in revenue and posted a SEK 1.3 million net loss in the fiscal year ending March, with four employees at that time. LinkedIn profiles suggest the team has since grown to 17.
Sistafund, a €70 million pan-European fund backing female founders and gender-balanced teams, led the round. Partner Marie Geneste, who joined Rebaba's board, told Swedish outlet Impact Loop that the firm invested for "circularity without compromise" and a team capable of building a European leader in the space.
Rebaba won Techarenan's Startup Company of the Year award in 2024 and was named a Brilliant Innovator by Brilliant Minds earlier this year. Law firm Mannheimer Swartling advised on the financing.
