BMW and Rimac Redefine Electric Luxury: A Deep Dive into the Next-Generation i7 Battery Architecture

The automotive landscape is witnessing a seismic shift in electrification strategy as the BMW Group, in a landmark collaboration with Rimac Technology, prepares to unveil a transformative update to its flagship electric sedan, the i7. This partnership represents more than a simple product enhancement; it is a strategic fusion of BMW’s mass-production expertise and Rimac’s pioneering high-performance battery engineering. By integrating a cutting-edge Hochvoltbatterie (high-voltage battery) system based on the 4695-cylindrical cell format, BMW is effectively bridging the gap between its current Gen5 technology and the highly anticipated "Neue Klasse" platform.

The Genesis of Innovation: Why the 4695 Cell Matters

At the heart of this technical evolution lies the introduction of 4695-format cylindrical lithium-ion cells. With a diameter of 46 mm and a height of 95 mm, these cells form the cornerstone of BMW’s sixth-generation (Gen6) eDrive technology. For years, the industry has relied on prismatic cells, which were easier to package within specific floor structures but lacked the volumetric efficiency now demanded by the next generation of long-range electric vehicles (EVs).

The shift to 4695 cylindrical cells offers a roughly 20% increase in volumetric energy density compared to the Gen5 prismatic counterparts. This density improvement is not merely a numbers game; it is the enabler for the extended range and accelerated charging profiles that define the luxury EV segment. Cylindrical cells provide superior thermal management, allow for more efficient packaging, and benefit from a design that is inherently more scalable—a critical factor for automakers looking to standardize battery production across multiple model lines.

Chronology of a Strategic Partnership

The collaboration between BMW and Rimac did not happen overnight. It is the culmination of a multi-year effort to push the boundaries of energy storage.

• Initial Conceptualization (2023–2024): BMW identifies the need to accelerate the deployment of its Gen6 technology to maintain its competitive edge in the luxury segment. Rimac, having already established its reputation as a powerhouse in hyper-EV battery systems, is identified as the ideal development partner.
• The Investment Phase (2025): Rimac invests approximately €130 million into a dedicated, high-tech manufacturing facility on its campus near Zagreb, Croatia. This 15,000-square-meter site is purpose-built to handle the precision requirements of the new 4695 cells.
• System Integration (Late 2025 – Early 2026): Engineers from both companies work in tandem to merge the Gen6 cell chemistry with a modified version of the Gen5 modular architecture.
• The Global Unveiling (April 22, 2026): The automotive world is set to witness the official debut of the refreshed BMW i7 at the Auto China 2026 exhibition, showcasing the culmination of this high-stakes engineering endeavor.

Technical Architecture: The Hybrid Synergy

Perhaps the most impressive feat of engineering in this update is the integration strategy. Rather than waiting for an entirely new platform, BMW has opted to combine the new Gen6-style cells with a proven Gen5 modular chassis. This "hybrid" approach allows BMW to utilize its existing, highly efficient manufacturing infrastructure while reaping the benefits of the advanced cell chemistry.

Thomas Engelhardt, Senior Vice President of High-Voltage Storage Development at BMW, noted that the team sought a "bespoke solution" designed specifically for the weight and performance demands of a luxury limousine. The engineering challenge was not just about the cells themselves, but how they interact with the vehicle’s existing thermal management systems and power electronics.

Mate Rimac, CEO of Rimac Technology, emphasized that the synergy lies in the "systemic approach." By optimizing the interplay between the cell chemistry and the battery management software, the partners have created a system that maximizes the performance envelope of the 4695 format without requiring a complete overhaul of the vehicle’s electrical architecture.

Supporting Data: Translating Tech into Range and Speed

The current BMW i7 offers a usable battery capacity of approximately 101.7 kWh, providing a WLTP-certified range of up to 624 km. With the 20% increase in volumetric energy density provided by the new Gen6 technology, market analysts and industry insiders expect a significant leap in real-world performance.

Conservative estimates suggest a range extension of over 100 km, potentially pushing the flagship sedan into the 700 km to 750 km territory. Beyond pure distance, the focus is on the "C-rate"—the measure of the rate at which a battery is discharged or charged relative to its maximum capacity. The new system’s lower internal resistance allows for sustained high-power charging, meaning the i7 can recover significant range in the time it takes for a driver to enjoy a coffee at a high-speed charging hub.

However, the efficacy of this charging remains dependent on external variables:

1. Ambient Temperature: Maintaining optimal thermal equilibrium for the cells.
2. Infrastructure Capability: The vehicle must be supported by 350 kW+ charging stations to reach its theoretical potential.
3. State of Charge (SoC) Curves: The ability of the battery management system to handle high currents as the battery reaches higher charge levels.

Industrial Implications: The Shift to Tier-1 Specialization

The production logistics for the new i7 battery represent a blueprint for the future of the automotive supply chain. With a capacity of roughly 300,000 modules per year (enough for 50,000 complete battery packs), the Rimac facility in Zagreb serves as the primary engine for this innovation.

Once manufactured, these sophisticated packs are transported to the BMW factory in Dingolfing, Germany, for final vehicle assembly. This workflow highlights a growing trend: OEMs are increasingly treating the battery as a modular "black box" developed by high-end specialists, allowing the main assembly lines to focus on the vehicle’s holistic integration. For Rimac, this marks a transition from a niche hypercar manufacturer to a key Tier-1 automotive supplier, effectively validating their business model in the mass-market premium sector.

Future Outlook: A Stepping Stone to the "Neue Klasse"

Why implement this technology in the current i7 if the "Neue Klasse" platform is just around the corner? The answer lies in the iterative nature of modern engineering. The i7 serves as the perfect laboratory for high-volume deployment of the 4695 technology.

By stress-testing these cells in a flagship vehicle that demands the highest levels of refinement and reliability, BMW is building a data library that will inform the final production parameters of the "Neue Klasse" vehicles. This is a risk-mitigation strategy that ensures the next generation of platforms is not just innovative, but battle-tested.

The partnership also underscores a broader European push to secure the EV supply chain. By fostering collaboration between a German automotive giant and a Croatian technology leader, the industry is creating a robust, localized ecosystem that reduces dependence on external markets and accelerates the pace of European innovation.

Conclusion

The updated BMW i7, with its Rimac-developed battery system, stands as a testament to the fact that the evolution of the electric car is far from over. As we approach the official premiere in April 2026, it is clear that the focus has shifted from mere "electrification" to "optimization."

For the end user, this translates to less time tethered to a charging station and more freedom on the open road. For the engineer, it is a masterclass in hybrid architecture and cross-company collaboration. As the 4695 cell becomes the new gold standard for BMW, the i7 will be remembered not just as a luxury sedan, but as the vehicle that ushered in the next era of high-density, high-performance electric mobility. The stage is now set for a new benchmark in the luxury automotive sector, where the marriage of software, chemistry, and mechanical engineering creates a driving experience that was, until recently, strictly theoretical.