ProLogium and Rimac Reveal Cell-to-Pack Battery Concept, Road Trials Set for 2028

At the Paris Motor Show, battery developer ProLogium and Rimac Technology pulled the wraps off a concept mockup of a pouch cell-to-pack battery, offering the clearest look yet at how the two companies intend to fuse advanced cell chemistry with pack-level engineering. The design is still a demonstrator, but it signals a shift in how the partners view the solid-state race: integration, not just chemistry, is becoming the deciding factor for when these batteries actually reach cars.

The timeline laid out by the pair is methodical. A functional battery segment is expected at CES 2027, with a full-scale working pack following later that same year. On-road and in-vehicle trials are then pencilled in for the second half of 2028. Each milestone is designed to answer a specific question — whether thermal management and cell integration concepts can survive real automotive demands before the programme scales up.

The collaboration was formalised through a memorandum of understanding signed at IAA in September 2025, pairing ProLogium’s cells with pack engineering from Rimac Technology. According to Principal Product Architect Daniel Kišić, Rimac is evaluating several integration approaches in parallel on functional segments, covering heat, swelling and overall system design. Some of these prioritise energy density and lower weight, while others lean toward performance.

One of the most practical hurdles is swelling management, a known challenge for solid-state pouch cells. With road testing still more than two years away, any production application sits even further out. Still, Kišić noted that a validated pack would cut weight, giving automakers a choice: more energy at the same mass, a smaller pack delivering the same range, or a blend of both.

ProLogium founder and Chief Executive Vincent Yang described the Paris display as the baseline of the collaboration, adding that functional segments are already in development. The mockup may be static for now, but it marks a concrete step in a partnership that aims to prove solid-state integration is viable long before it reaches showroom floors.