PressureBat

Lithium-ion batteries are a key technology for the energy transition today. They enable electric mobility and are also increasingly being used in stationary energy storage systems to provide electricity from wind and solar power when needed. In this way, they make a significant contribution to climate-friendly mobility and a secure energy supply.

At the same time, manufacturers face the challenge of producing battery cells in large quantities reliably, cost-effectively, and with efficient use of resources. Significant challenges remain in this area: battery cell production continues to be associated with high scrap rates, particularly during the ramp-up phase of new or modified production lines. This scrap increases the amount of materials and energy required per usable cell, reduces the economic efficiency of production, and ultimately affects the cost of battery systems.

One major reason is that, although key factors influencing cell quality are known, they have not yet been sufficiently captured and systematically utilized in production. This applies in particular to the mechanical stresses inside the cell, which arise during key process steps and have a substantial influence on cell performance, service life, and safety.

The PressureBat collaborative project addresses this issue with the aim of continuously monitoring internal cell pressure in battery cells and using the resulting data to derive concrete approaches for improving process control. To achieve this, the project consortium is developing and integrating area-based pressure sensors capable of measuring pressure inside the cell with spatial resolution. This makes it possible to identify whether and where localized excessive or insufficient mechanical loads occur. Such conditions often remain undetected at present and may only become apparent later through defects or accelerated aging.

The measurement data are systematically evaluated throughout the process chain in order to identify typical load profiles, correlate them with cell quality characteristics, and derive targeted optimization measures. This creates an integrated approach that provides reliable information for both battery cell production and subsequent cell operation.

The core innovation of PressureBat lies in establishing internal cell pressure as a new quality parameter that can be continuously monitored during battery cell production, thereby closing an existing gap in quality assurance and condition assessment. This strengthens quality assurance in manufacturing, improves operational safety, and can extend the service life of battery cells by enabling critical mechanical loads and emerging damage to be detected and assessed at an earlier stage.

The project follows a comprehensive development and validation approach for cell-integrated pressure sensors in prismatic lithium-ion battery cells. First, pressure loads throughout the entire cell production process are analyzed, and requirements for the sensors, measurement methods, and data acquisition are derived from this analysis.
Building on this, suitable pressure sensors will be selected, tested for material durability and functionality, and further developed for integration into battery cells. Subsequently, a scalable concept for integrating the sensors into prismatic cells and industrial production processes will be developed, prototyped, and implemented in a production-like environment.
The collected pressure data is used to identify critical stresses during cell manufacturing and formation, as well as to investigate correlations between pressure profiles, cell quality, and aging. From this, measures are derived to optimize production processes, quality assurance, and cell performance. Finally, a pressure-based methodology for evaluating battery health and predicting service life at the cell and module levels is validated and further developed.

The project lays the groundwork for utilizing internal cell pressure as an additional quality and condition parameter in battery cell production and operation. The sensor, analysis, and integration concepts developed can be used in the future to improve process control, reduce scrap, and increase the safety and service life of battery systems. The results thus offer potential for industrial application in cell manufacturing, quality assurance, and battery condition monitoring.