Mechanical battery testing: complex and cost-intensive – but essential for safety, service life, and performance. In an exclusive interview with Battery-News, Dr. Simon Vitzthum, Head of Global Industry Management, explains how international testing systems and services provider ZwickRoell is responding to the rapidly changing requirements.
Battery-News: The battery industry is growing worldwide. Why is mechanical testing so important in this sector in particular?
Dr. Simon Vitzthum: The automotive industry – as one of our most important markets – is undergoing a profound transformation process towards electric mobility. The focus here is on the battery, both in terms of its performance and its safety. Mechanical testing methods make a decisive contribution to this because they make it possible to examine the structural integrity and behavior of battery cells under real conditions. This is essential to ensure both the cells’ safety and service life. Another aspect is reproducibility. Many failure mechanisms in battery cells – such as shocks or pressure loads – can only be reproducibly investigated and compared using standardized mechanical test methods. This is an enormous advantage, especially in the development of new cell formats and materials.
Battery-News: What exactly sensitized you to the topic of battery testing?
Vitzthum: It was clearly our close collaboration with customers. We keep a very close eye on how markets are developing and respond to specific inquiries. It often starts with a need to test an electrode, followed by questions about the cell or module. This results in new fields of application. In addition to industry, universities and research institutes are also important sources of inspiration. This combination of customer projects and scientific collaboration is a key driver of our further development.
“Of course, mechanical testing is complex and cost-intensive – but it is also essential for safety, service life, and performance.”
Battery-News: How do you ensure that your testing methods can keep up with the dynamics of battery production – for example in gigafactories?
Vitzthum: Of course, mechanical testing is complex and cost-intensive – but it is also essential for safety, service life, and performance. Our aim is to develop highly efficient, targeted and, where possible, automated testing approaches that deliver reproducible data – regardless of the operator. It is important to plan for mechanical tests as early as the research and development stage. To this end, we have set up our own battery laboratories in Ulm and in Shanghai, among other places, where we work hand in hand with customers on individual solutions.
Battery-News: You say that battery testing is much more than end-of-line testing. What is your strategic approach?
Vitzthum: Exactly, end-of-line testing alone is too late. Our approach is to accompany testing along the entire value chain. We differentiate between three levels: the cell components – for example aluminum and copper foils or separators –, then the battery cell itself, and finally the battery system, which means the entire high-voltage storage system. Each level has its own requirements – from testing the thinnest materials to structural tests in the system network. The key is to start testing as early as possible and to pursue a consistent strategy.
“New technologies such as solid-state batteries bring along specific challenges like a volume increase during the charging process.”
Battery-News: Battery cells vary greatly in terms of design and material. How flexibly can your test methods react to this?
Vitzthum: The variety is indeed enormous, from pouch to prismatic to round cells – and there are new technologies such as solid-state batteries, which bring with them specific challenges, such as swelling – which means the increase in volume during charging that changes the pressure conditions in battery packs. New manufacturing processes, such as dry coating, also require adapted test methods, for example for adhesion assessment. At the same time, there are hardly any standards in this field. This makes our experience of more than 160 years of testing technology and our ability to adapt methods from other areas all the more important. In our specialized battery laboratory in Ulm, we work specifically on test methods.
Battery-News: Do you think there will soon be standards for battery testing?
Vitzthum: That is difficult to predict. The range of cell types, cell chemistry, and cell designs is currently too wide and the speed of development too high. Standards would hardly be able to keep pace with this. I see more opportunities for standards at material level, for example for ultra-thin films. We recently carried out a tensile test on a 4.5-micrometer film – which is a completely different challenge compared to a conventional steel tensile specimen.
“We have developed a testing system that simultaneously measures mechanical forces, regulates the temperature, and determines the electrical conductivity of an electrode.”
Battery-News: How do you develop your testing devices to meet all these requirements?
Vitzthum: Our drive is not just to supply machines, but to create real customer benefits. We rely both on customized solutions and on standardized testing solutions that can serve as orientation – precisely because there are hardly any standards to date. A concrete example: We have developed a testing system that simultaneously measures mechanical forces, regulates the temperature, and determines the electrical conductivity of an electrode. Such interdisciplinary requirements are typical in the battery sector, and this is what we are focusing on.
Battery-News: You mentioned the importance of universities. What is the value of interdisciplinary collaboration?
Vitzthum: It is extremely important. We work closely with universities in Germany and abroad – both in research projects and pragmatically in the form of providing equipment and a joint exchange. The battery industry is more interdisciplinary than almost any other field. Chemists, electrical engineers, mechanical engineers, physicists: Everyone is involved. We have already conducted tests in liquid media or at high temperatures. Such requirements show how broad the spectrum is – and also how important collaboration across disciplines is.
