The Importance of Mechanical Testing in the Evolving Battery Industry: Insights from ZwickRoell’s Dr. Simon Vitzthum

“When There Are Hardly Any Standards, Experience Decides”

Mechanical battery testing is intricate and costly, yet it is crucial for ensuring safety, service life, and performance. In an exclusive interview with Battery-News, Dr. Simon Vitzthum, Head of Global Industry Management at ZwickRoell, an international provider of testing systems and services, discusses how the company is adapting to the rapidly evolving requirements of the battery industry.

**Battery-News:** The battery industry is expanding globally. Why is mechanical testing particularly vital in this sector?

**Dr. Simon Vitzthum:** The automotive industry, one of our key markets, is undergoing a significant transformation towards electric mobility. The battery is at the center of this shift, especially concerning its performance and safety. Mechanical testing methods play a crucial role in assessing the structural integrity and behavior of battery cells under real-world conditions. This is essential for ensuring the safety and longevity of the cells. Additionally, reproducibility is vital; many failure mechanisms in battery cells, such as shocks or pressure loads, can only be reliably investigated and compared using standardized mechanical testing methods. This is especially beneficial when developing new cell formats and materials.

**Battery-News:** What sparked your interest in battery testing?

**Vitzthum:** Our close collaboration with customers has been pivotal. We closely monitor market developments and respond to specific inquiries. Often, it begins with a need to test an electrode, which leads to further questions about the cell or module, opening up new application areas. Universities and research institutes also inspire us. This combination of customer projects and scientific collaboration drives our innovation.

**Battery-News:** How do you ensure your testing methods keep pace with the dynamics of battery production, particularly in gigafactories?

**Vitzthum:** Mechanical testing is undoubtedly complex and costly, but it is crucial for ensuring safety, service life, and performance. Our goal is to develop highly efficient, targeted, and, where feasible, automated testing approaches that yield reproducible data, regardless of the operator. It is essential to plan mechanical tests early in the research and development phase. To facilitate this, we have established our own battery laboratories in Ulm and Shanghai, where we collaborate closely with customers on tailored solutions.

**Battery-News:** You mentioned that battery testing involves much more than just end-of-line testing. What is your strategic approach?

**Vitzthum:** Absolutely, end-of-line testing is insufficient on its own. Our approach involves supporting testing throughout the entire value chain. We categorize this into three levels: the cell components—such as aluminum and copper foils or separators—the battery cell itself, and finally, the battery system, which encompasses the entire high-voltage storage system. Each level has its unique requirements, from testing the thinnest materials to conducting structural tests in the system network. The key is to initiate testing as early as possible and maintain a consistent strategy.

**Battery-News:** Given the wide variation in battery cell designs and materials, how adaptable are your testing methods?

**Vitzthum:** The variety is indeed vast, ranging from pouch to prismatic to cylindrical cells. New technologies, such as solid-state batteries, present specific challenges, including volume expansion during charging, which alters pressure conditions in battery packs. Furthermore, new manufacturing processes, like dry coating, require adapted testing methods, particularly for assessing adhesion. The lack of standards in this domain underscores the importance of our extensive 160 years of experience in testing technology and our ability to adapt methodologies from other areas. Our specialized battery laboratory in Ulm focuses on developing innovative test methods.

**Battery-News:** Do you foresee the establishment of standards for battery testing in the near future?

**Vitzthum:** It’s difficult to predict. The diversity of cell types, chemistries, and designs is currently too vast, and the pace of development is too rapid for standards to keep up. However, I see potential for standards at the material level, particularly for ultra-thin films. For instance, we recently conducted a tensile test on a 4.5-micrometer film, which poses entirely different challenges compared to conventional steel tensile specimens.

**Battery-News:** How do you develop your testing devices to meet these diverse requirements?

**Vitzthum:** Our aim goes beyond simply supplying machines; we strive to provide genuine customer benefits. We focus on both customized solutions and standardized testing methods that can serve as guidelines, especially given the current lack of standards. A concrete example is our testing system that simultaneously measures mechanical forces, regulates temperature, and assesses the electrical conductivity of an electrode. Such interdisciplinary requirements are typical in the battery sector, and this is where we concentrate our efforts.

**Battery-News:** You highlighted the significance of collaboration with universities. What is the value of interdisciplinary cooperation?

**Vitzthum:** Interdisciplinary collaboration is crucial. We work closely with universities both in Germany and internationally, engaging in research projects and pragmatically providing equipment and sharing knowledge. The battery industry encompasses a broad range of disciplines, including chemistry, electrical engineering, mechanical engineering, and physics. We have conducted tests in various environments, such as liquid media or at elevated temperatures. These requirements illustrate the broad scope of the industry and the importance of cross-disciplinary collaboration.