The Ghost in the Battery: How Voltfang Uses AI and IoT to Give EV Batteries a Second Life
photos: Voltfang
Europe's electric vehicle fleet continues to expand, while electricity networks are being asked to absorb larger volumes of renewable energy from solar and wind generation. The result is a growing need for Battery Energy Storage Systems (BESS) capable of balancing intermittent power supply, reducing grid pressure and shifting energy consumption away from expensive demand peaks.
At the same time, lithium-ion batteries contain substantial embedded value. Manufacturing them is energy intensive, resource intensive and dependent on supply chains Europe is still working to strengthen.
Immediately dismantling batteries that still retain most of their storage capability raises an obvious question: should Europe treat them as waste, raw material or infrastructure?
Aachen-based Voltfang has built its business around the third answer.
Founded at RWTH Aachen University in 2020, the company develops Battery Energy Storage Systems (BESS) using second-life electric vehicle batteries. Voltfang positions itself as a central partner for BESS projects, combining battery technology, project implementation and economic structuring in an effort to standardise deployments, improve bankability and create investor-friendly projects with clearly defined risk profiles.
That makes Voltfang part battery manufacturer, part software company and part circular economy infrastructure developer - an integrated unit with the aim of turning used, unevenly aged battery modules into predictable, financeable energy assets.
No two retired EV batteries are alike
Building a new battery system from fresh cells is relatively predictable.
The cells originate from controlled production environments. Their performance characteristics are known. Their operating limits can be modelled with reasonable confidence.
Second-life batteries are different as every battery module arrives with its own history. Some may have spent years operating in cold climates. Others may have experienced frequent rapid charging sessions. Some have gone through thousands of shallow cycles, some may have been subjected to more demanding usage patterns. Even batteries produced by the same manufacturer can age differently.
For second-life energy storage, this variability is the central engineering challenge. How much usable capacity remains? How quickly will degradation continue? Can battery modules from different vehicles operate reliably within the same stationary storage installation? Answering these questions determines whether second-life batteries become a scalable infrastructure category or remain a niche sustainability exercise.
Voltfang's approach to this relies on testing, classification and software-based monitoring. Incoming battery modules are assessed for their State of Health (SoH) before they can be safely integrated into Battery Energy Storage Systems. In practical terms, the company must transform uncertain battery assets into known industrial components. That is where data becomes essential. A reused battery is not merely a physical object. It is also a record of remaining capacity, voltage behaviour, thermal performance and degradation risk. The more accurately those characteristics are understood, the easier it becomes to deploy second-life batteries in commercial, industrial and utility-scale energy storage projects.
The deeptech layer: telemetry, IoT and connected battery storage
Battery Energy Storage Systems increasingly resemble connected industrial devices. From the outside, a battery cabinet appears static. Internally, however, it continuously generates operational information, including temperature, voltage, charging behaviour, discharge profiles and overall system status.For second-life batteries, this visibility is particularly important.
Voltfang has publicly discussed cloud-connected architectures and the use of Amazon Web Services technologies within its energy infrastructure ecosystem. The strategic rationale is straightforward: distributed battery assets need to be monitored, maintained and optimised as fleets rather than isolated installations. Connectivity enables operators to compare performance across sites, identify anomalies before they become failures and improve operational transparency. It also supports remote maintenance and software updates.
Traditional energy infrastructure was often installed and left largely unchanged for years. Modern battery storage increasingly follows a software-centric model. Firmware can be updated remotely, security improvements can be deployed without site visits, and operating strategies can evolve as more performance data becomes available.
For Voltfang, this digital layer is not a secondary feature. It is essential to making second-life battery storage reliable, scalable, and investable.
Venma: the AI-driven energy management system
Voltfang's proprietary Energy Management System, known as Venma, is designed to optimise how battery storage systems interact with buildings, renewable energy generation, electricity markets and grid infrastructure.
This makes sense as commercial and industrial customers do not purchase batteries simply to own storage capacity: they deploy Battery Energy Storage Systems to lower electricity costs, increase self-consumption of renewable energy, reduce peak demand charges and participate in energy flexibility markets.
Peak shaving is among the most significant applications. Many commercial electricity tariffs include charges based on maximum power consumption levels. A short-lived spike in demand can increase annual energy costs considerably. Battery storage systems can reduce those peaks by supplying stored energy when consumption rises rapidly. The result is reduced grid dependency and improved energy economics.
Voltfang presents Venma as an intelligent software platform capable of optimising self-consumption, integrating dynamic electricity tariffs and supporting participation in energy markets.
Investors are funding a new infrastructure category
In 2025, Voltfang secured €15 million in Series B funding in a round led by Dutch deeptech investor FORWARD.one. Other investors included Interzero, Helen Ventures, PT1, Daphni, Aurum Impact, Fiege Ventures and Newberry Investments.
The investor mix reflects a convergence of interests. Circular economy investors see an opportunity to extend material lifecycles, energy investors see growing demand for flexible storage capacity, and infrastructure investors increasingly recognise battery assets as long-term investment opportunities.
Voltfang also secured a €3 million commercial line from Commerzbank. Although less visible than venture capital financing, access to debt facilities is particularly important in energy infrastructure. Battery storage companies need to procure equipment, finance projects, manage inventories and deliver systems that may operate for decades. Balance sheet flexibility becomes an enabling technology in itself.
What will have boosted confidence in Voltfang is that it has organisations including ALDI Nord, Stuttgart Airport, Goldbeck, Phoenix Contact and Schaltbau among its customers. Its work has also attracted recognition from Germany's cleantech ecosystem. Voltfang has received the German Sustainability Award, the German Innovation Award in the Business-to-Business Energy Solutions category and the EES Award. Together, these distinctions indicate growing industry interest in technologies that can extend battery lifecycles while strengthening electricity networks.
Scaling towards gigawatt-hour capacity
Voltfang is scaling up in an industrialisation process that will be interesting to follow: second-life batteries have historically been viewed primarily as an environmental concept rather than an industrial manufacturing category.
The company last year stated that its Series B funding would support production expansion and the deployment of an additional 250 MWh of storage capacity across Europe. Also in 2025, it opened its Future Fab production facility in Aachen.The site is intended to manufacture BESS for commercial, industrial and utility-scale applications using second-life electric vehicle batteries. Current plans envisage production capacity reaching 250 MWh annually in the near term, with scalability towards 1 GWh before the end of the decade.
Voltfang's partnership with infrastructure investor Palladio Partners pushes the narrative further into the realm of institutional infrastructure investment. Announced in 2025, the collaboration aims to mobilise approximately €250 million for battery storage projects in Germany by 2029. The partnership covers project development, financing, implementation and operation. Voltfang contributes technology and operational expertise while Palladio provides infrastructure investment experience and long-term capital.
Hardware bound by software
Europe's battery story is usually told as a race to build more gigafactories, secure more raw materials and manufacture more cells.
Voltfang points to another chapter that is only beginning to emerge.
Over the coming decade, millions of batteries will leave Europe's roads carrying far more energy than the automotive industry still requires from them. Whether they become waste, raw material or infrastructure will depend less on chemistry than on software, data and economics.
For companies like Voltfang, the most interesting battery may not be the one rolling off a production line today, but the one that has already completed its first journey and is waiting to begin a second.
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