The EU Battery Regulation (EU) mandates a digital battery passport for traction, light‑mobility, and industrial batteries above 2 kWh from February 2027 onward, regardless of cell chemistry. As a result, lead‑acid batteries—widely deployed in industrial vehicles, backup systems, and motive‑power applications—must fulfill the same transparency and lifecycle documentation requirements as lithium-based batteries. Given their strong cost sensitivity, thin margins, and highly optimized production processes, compliance must be achieved with minimal impact on manufacturing economics.

From an industry perspective, lead‑acid batteries face a particular challenge: even small increases in production overhead—such as additional traceability features, data‑capture hardware, secure information technology (IT) integration like data transfer, or conformity assessments—can disproportionately affect unit costs compared to higher‑value chemistries. At the same time, the structured data ecosystem enabled by the battery passport offers potential economic benefits. Lead‑acid technology already relies on efficient, established recycling loops; enhanced material and emissions traceability supports more robust reporting, improves second‑life assessments, and strengthens circular‑economy performance. Additional long‑term advantages include improved failure analysis, reduced warranty expenditure, and more accurate residual‑value determination.

To leverage these benefits, a lightweight Battery Management System (BMS) was developed within the projects LoCEL-H2 (101096033) and Railway‑X (13IPC029E) to enable dynamic data acquisition, including state‑of‑health (SoH), charge and discharge profiles, temperature history, cycle counts, and service records. Although lead‑acid batteries are intrinsically robust, they are susceptible to characteristic degradation mechanisms such as sulfation, deep‑discharge stress, and operational misuse. Standardized data infrastructures—such as those promoted by the Battery Pass Consortium and the Global Battery Alliance—facilitate more accurate diagnostics, predictive maintenance, and a reduction in premature failures, thereby compensating part of the additional regulatory burden.

An example for BMS advantages is the implementation of regular equalization charges into the algorithm. It can be shown via a pSoC (partial state of charge) test procedure with equalization charge frequency and duration variability that the adequate deployment of equalization charges was beneficial for the battery life and capacity retention of the lead acid battery.

This poster provides an overview of the design challenges associated with developing a BMS for lead‑acid batteries. It further presents the resulting functional requirements and offers a detailed assessment of implementation effort versus anticipated operational and economic benefits.