Battery production is at the heart of global industrial and climate policy. With the growing global demand for energy storage systems for electromobility and stationary applications, the importance of efficient, sustainable and regionally independent production is also increasing.
© Pulsar Photonics GmbH
The framework conditions for battery production in particular present companies with immense challenges: The dependence on raw materials such as lithium, cobalt and nickel is causing geopolitical tensions. At the same time, supply chains are becoming increasingly fragile due to global crises and rising transportation costs.
Europe is therefore faced with the task of establishing a resilient value chain that includes both raw material extraction and further processing as well as recycling – after all, used batteries are the most productive German lithium resource. In addition, production processes must be able to be flexibly adapted to new battery concepts such as solid-state or sodium-ion batteries for reasons of investment security.
In view of these challenges, it is clear that the future of battery production in Europe can only be secured by using state-of-the-art technologies. Laser technology in particular offers solutions to meet the key requirements of efficiency, precision and sustainability. Whether in material processing, electrode production or recycling: without innovative laser processes, competitive and sustainable battery production in Europe is hardly conceivable.
Raw material processing and material refinement: the basis for sustainable battery production
Fraunhofer ILT, Aachen
Materials such as lithium and nickel are still components of current battery cells. Their chemical and physical properties enable high energy densities and long lifetimes, but their extraction and processing pose complex problems. However, battery technologies are developing rapidly with the aim of minimizing the use of rare and expensive raw materials.
CATL already presented a sodium-ion battery in 2021 that completely dispenses with lithium and cobalt. In April 2024, the Chinese battery manufacturer introduced a cobalt-free lithium iron phosphate (LFP) battery with a range of over 1,000 kilometers. It can charge enough energy for 600 kilometers in just ten minutes, which corresponds to a charging speed of one kilometer per second.
Toyota plans to use solid-state batteries in hybrid vehicles from 2025. Nissan has put a prototype production plant for laminated solid-state batteries into operation in Japan. Panasonic has presented a solid-state battery for drones.
VW and Mercedes, Ford and BMW are about to introduce solid-state batteries or have entered into strategic partnerships. A key starting point for new accumulator technologies is material refinement at nano level, in which raw materials are specifically processed and functionalized in order to maximize their performance in accumulators. The Surface Technology and Shape Ablation department at the Fraunhofer Institute for Laser Technology is researching this. Modern laser technologies enable precise interventions in the material structure while minimizing the consumption of resources.
© Fraunhofer ILT, Aachen
Another example of the successful use of laser technologies can be found in the collaboration between the Fraunhofer ILT, the Chair of Laser Technology LLT at RWTH Aachen University, Trumpf and the Deutsches Elektronen-Synchrotron Desy. By using X-rays from a particle accelerator, it was possible to gain deeper insights into laser welding processes. This showed that the use of lasers with a green wavelength improves material utilization and reduces waste. These findings not only offer technological advantages, but also contribute to more sustainable production.
“These projects show that innovative laser technology can not only overcome the challenges of raw material processing, but also enable sustainable and competitive battery production in Europe,” explains Dr. Alexander Olowinsky, Head of Joining and Cutting at Fraunhofer ILT.
Fraunhofer ILT, Aachen
Electrode production: Innovations for sustainable production
The coating of the current conductor foils (copper or aluminum) with the electrode materials for the anode and cathode and their subsequent drying are crucial steps that influence both the energy density and the cycle life of the batteries. Conventional drying processes based on convection ovens, however, consume a considerable amount of energy and require a large amount of space, which limits the sustainability and efficiency of battery production.
The IDEEL project (Implementation of Laser Drying Processes for Economical & Ecological Lithium Ion Battery Production), funded by the German Federal Ministry of Education and Research, shows how laser drying solves these challenges: In the project, the drying of anodes and cathodes in a roll-to-roll process using a high-power diode laser was realized for the first time. This method significantly reduces energy consumption, doubles the drying speed and halves the space required.
“Laser drying not only enables more efficient process control, but also helps to significantly improve the carbon footprint of battery production,” explains Dr. Samuel Moritz Fink, Group Leader Thin Film Processes at Fraunhofer ILT. Together with the project partners, Fink and his team developed a laser drying module with adapted optics and process monitoring to ensure uniform drying. This approach also offers flexibility: existing convection ovens can be retrofitted with the laser technology, making it easier to implement in existing production lines.
Fraunhofer ILT, Aachen
In another research project, the Fraunhofer ILT is using specially developed multi-beam optics. This splits the laser beam into several partial beams that simultaneously process a 250 millimeter wide band of a lithium-ion anode. This high-precision structuring increases the energy density and fast-charging capability. Electrode production also benefits from the integration of artificial intelligence into the manufacturing process.
Researchers at the Fraunhofer ILT are currently investigating how AI-supported systems can be used to optimize process parameters. Such systems could not only further increase quality and productivity, but also lay the foundation for autonomous production.
Cell assembly: precision and efficiency through innovative technologies
In addition to drying the electrodes, the precise joining of the electrode materials also plays a central role in the performance and reliability of rechargeable batteries. Laser microwelding has established itself as a key technology here. It enables contactless, high-precision joining of materials such as copper and aluminum, which are essential for battery electrodes. Due to the low thermal load, the sensitive cell chemistry remains intact, while the electrical conductivity is optimized through reduced contact resistance. Laser microwelding offers a combination of flexibility and efficiency that traditional welding processes cannot match.
Fraunhofer ILT, Aachen
The requirements for laser microwelding vary depending on the cell format, as each cell type presents specific challenges when it comes to contacting. Cylindrical cells require a precise welding depth to ensure electrical conductivity on the one hand and to prevent damage due to overheating on the other. Contacting the negative pole is particularly challenging, as excessive heat could damage the sensitive polymer seal, which can lead to electrolyte leakage. In the case of pouch cells, which are characterized by their flexible design and high energy density, welding through the sensitive film coating must be avoided.
One promising development in cell assembly is the XProLas project, which Trumpf is implementing in collaboration with the Fraunhofer ILT and other partners. The aim is to develop compact, laser-driven X-ray sources that enable on-site quality inspection directly at the manufacturer’s premises instead of using large particle accelerators as was previously the case. This technology makes it possible to analyze battery cells in real time, allowing both the charging and discharging processes and the material quality to be monitored precisely.
This method opens up new possibilities, particularly when it comes to examining the cathode material, which plays a key role in determining the performance and durability of a battery. “By using brilliant X-ray sources, we can detect impurities and material defects at an early stage and thus significantly shorten development times,” explains Dipl.-Ing. Hans-Dieter Hoffmann, Head of the Lasers and Optical Systems department at Fraunhofer ILT.
The integration of artificial intelligence also opens up additional potential here: AI can monitor and adjust process parameters in real time. This allows deviations to be detected and corrected at an early stage, creating the basis for autonomous production. The vision of “first-time-right” production, in which all components are assembled flawlessly in the first run, is therefore within reach.
Fraunhofer ILT, Aachen
Module and pack production: efficiency and precision thanks to laser technologies
The individual cells are then connected to form modules and packs. Precision plays a decisive role at module level in particular, as the integration of several weld seams is necessary without increasing the thermal load on the sensitive cells. Laser processes such as microwelding enable customized adaptation to these requirements.
One of Fraunhofer ILT’s key innovations is the development of processes that enable the safe and precise joining of aluminum and copper – two materials with very different physical properties. Thanks to state-of-the-art laser beam guidance, the welding depth can be controlled so as not to damage sensitive cells.
“This technology is essential for the production of modules and packs that have to function reliably under extreme conditions, such as high currents and thermal loads,” explains Olowinsky. One example of this is the laser welding of large cylindrical cells, which has been further developed at the Aachen-based institute together with partners such as EAS Batteries GmbH. Here, attention is paid to the stable and durable interconnection of the cells in order to ensure a long service life and low failure rates.
In addition to laser welding, laser soldering has become established, particularly for joining heat-sensitive components. This process works at lower temperatures than traditional welding methods and thus protects sensitive electronics within the modules. This not only increases the reliability of the battery packs, but also contributes to the energy efficiency of production.
Battery management and sensor integration: intelligence for future-proof battery systems
Battery management is one of the central challenges of modern energy storage systems. The safety, longevity and performance of batteries depend largely on it – and not least the acceptance of electromobility. Advances in sensor integration and the use of AI offer transformative opportunities to meet these requirements.
Traditionally, batteries are monitored on a macroscopic level, but this only offers limited insight into the complex processes within the cells. This is where the integration of sensor technology during production offers new possibilities. Researchers at Fraunhofer ILT are printing sensors directly onto components or even integrating the smart measuring devices. These sensors enable real-time monitoring, such as the measurement of temperatures, forces or even chemical changes within the batteries.
“With additively manufactured sensors, we can continuously monitor the condition of the battery modules and react to potential faults at an early stage,” explains Samuel Fink. These sensors are only a few micrometers thick, precise and at the same time resistant to mechanical and thermal stress, which makes them ideal for use in batteries and battery modules. Their ability to provide continuous data enables predictive maintenance, which detects potential defects before they occur.
However, the integration of sensor technology alone is not enough to implement predictive maintenance. Sensors can detect changes in cell chemistry, while AI algorithms analyze this data and make predictions about the service life of the cells. Researchers in the “Data Science and Metrology” department at Fraunhofer ILT are developing such AI-supported algorithms that analyze large amounts of data from sensors in real time. These systems also make it possible to dynamically adapt processes, for example by optimizing temperature profiles during cell assembly or adjusting laser welding parameters.
Recycling and reuse: the path to a circular economy in battery technology
With the boom in battery technology, the need for sustainable strategies to recover valuable raw materials is also growing. An effective circular economy is essential to reduce dependence on primary raw materials while minimizing the environmental impact of battery production.
In the EU project ADIR, the Fraunhofer ILT is working with eight project partners from three countries to develop a sustainable recycling concept for electronic devices. The Acrobat project aims to develop a concept for recycling lithium iron phosphate batteries before they penetrate the market on a large scale. The aim of the project is to recover more than 90 percent of the critical materials. Together with partners such as Accurec Recycling, the Fraunhofer ILT is working on innovative separation and processing methods that are both ecologically and economically sustainable. The laser experts in Aachen are developing an inline characterization method to precisely evaluate the quality of the active material.
Laser spectroscopic analysis (LIBS) enables the precise identification and separation of complex material compositions. The researchers want to adapt this technology for the recycling of used batteries in order to further improve the recovery of metals such as cobalt and tantalum. Here, too, the integration of AI can analyse the large amounts of data from laser measurements in real time and derive process optimizations from this. This AI-supported monitoring enables dynamic adjustment of the recycling parameters, which reduces waste and increases the quality of the recycled raw materials.
Laser processes pave the way
Battery production is at the center of the electromobility transition and thus the focus of innovations that combine efficiency, sustainability and technological excellence. The technologies and developments presented along the production chain show how state-of-the-art laser processes can pave the way for a sustainable and competitive battery industry – from raw material preparation and electrode production to cell assembly and recycling. At the same time, AI-supported analysis and control systems create a new dimension of process control that improves production quality and sustainability and further reduces production costs.
In the future, AI-supported control loops could enable autonomous production in which processes adapt to changing conditions in real time. In addition, laser-driven X-ray sources and inline characterization technologies open up new possibilities for quality assurance and material analysis.
