Visionary Battery Systems

Interview on process-safe manufacturing – without a C-TYPE standard

Short-circuits, high voltage hazards, thermal runaway – the production of battery systems from charged battery cells is a highly critical process. No C-type standard exists for the manufacturing facilities for battery systems, for example those used in electromobility. What then should machine builders and operators use as a guide when building or retrofitting process-safe machines and plants for battery systems?

In this interview, Ulrich Hochrein, Head of Safety Engineering Services at EDAG Production Solutions GmbH & Co. KG in Fulda, and Andreas Centner, Sales Manager Automotive & Electronics, and Meik Kettinger, Key Account Manager Automotive & Electronics, at SICK Vertriebs-GmbH in Düsseldorf, examine the process and safety engineering aspects specific to the assembly of battery systems and recycling of battery systems.

What are the biggest challenges and hazards when manufacturing battery systems?

Ulrich Hochrein: In principle, the same requirements on machine safety need to be placed on automated battery production facilities as for other machines. Due to the product being manufactured - battery systems - additional requirements apply. Since the battery systems are assembled using partially charged battery cells, errors in the production technology can be far more critical because the battery cells or battery elements pose additional fire and explosion hazards. The risk varies depending on the cell chemistry used for the battery cells. A simple error by a mechanical robot that physically damages a battery cell could, for example, trigger a so-called thermal runaway. The same also applies to short circuits between the battery cells. Besides the fire and explosion hazards, which are difficult to control, highly critical substances that are explosive or carcinogenic or could cause gene mutations might be released that could pose a risk to employees and the plant technology and contaminate the production hall.

How can these hazards be successfully managed and contained?

Andreas Centner: As in other areas and sectors of factory automation, advanced sensors, automation solutions and safety technologies play a central role in this. The aim is to continuously monitor the production processes and avoid potential hazards or detect them early. This creates a fundamentally safer and more efficient production environment. 

Ulrich Hochrein: It is important to correctly assess the risk and to plan the system as a whole based on the findings from the risk assessment. In doing so, it is crucial to already obtain the pertinent information at the system planning stage. This applies not only to the battery systems themselves, for example their dimensions and the chemistry of the cells they contain, but also the question of to what extent the transport packaging has already been designed to ensure a reproducible positioning of the battery system at an automatic picking robot while considering relevant safety aspects. Even though the production technology is comparable to other machines, a battery assembly system will be more costly than comparable machines. This begins with higher space and time overheads in logistics if, for example, the battery cells need to be transported by manned forklift trucks. State-of-the-art industrial trucks should also be used. The automation technology should be designed so that any errors due to the production technology do not damage the battery cells and semi-assembled battery systems. This can be complex in several respects and result not only in higher component costs but also additional costs for setting up, documenting and validating the systems. Abnormal conditions need to be detected without delay using additional sensor technology. Reject facilities and the provision of emergency containers as well as other special functionality need to be implemented in response to the risk assessment. The company organization should also be structured differently. High voltage representatives and emergency response coordinators must be prepared at all times to avoid emergency events as best as possible and, when they do arise, ensure the consequences are as minor as possible. 

What particular hazards do emergency events in manufacturing pose? 

Ulrich Hochrein: When we speak of emergency events, we usually mean battery elements in the thermal runaway state. This is a self-perpetuating, exothermic chemical reaction of the battery elements where very high temperatures are quickly reached and the scenario quickly spreads to further battery elements. The chemical substances in the battery cell, some of which are reactive, toxic and inflammable and also have a very high energy density, pose a high risk. Such situations are not localized events any more, they affect the entire fire compartment or production hall. The number of at-risk employees quickly rises, the economic damage also. Furthermore, after the incident it is generally not possible to simply resume production because production areas may in some cases first need to be decontaminated with considerable effort.

What role does sensor technology play in production reliability, for example in relation to real time processing monitoring? 

Meik Kettinger: For battery manufacturers, it is particularly important to ensure safety in all phases of production as the materials and processes are often associated with high risks. They therefore need to avoid emergency events or detect them at the earliest possible stage. Real-time capable sensors play an important role in this. At SICK, we rely amongst other things on camera sensors for detecting foreign objects and thermography sensors for detecting hotspots, both of which can be seamlessly integrated into production systems. These sensors continuously monitor the battery systems and their environments, report potential hazards within milliseconds, and enable immediate measures to be taken to prevent emergency events and their consequences. By accurately assessing the hazards, we can install tailored monitoring solutions that not only increase safety but also improve the efficiency of the production processes.

Recycling is an important issue: What particular aspects, problems or even challenges do you see here? 

Ulrich Hochrein: Let me begin with a few figures that illustrate the relevance of recycling. Up to 70 percent of the costs of a battery system are material costs. The proportion of materials that need to be purchased abroad is significantly higher again. This means that the re-use and recycling of battery systems is not only important ecologically and economically but also in terms of geopolitical economics. It is advantageous for the recycling market that the recycling tonnage they can expect in the foreseeable future can be well estimated. Nevertheless, only a few recycling businesses are able to cover their costs at present. 

 Companies are also currently facing several challenges. Whether it be the recycling facilities or the manufacturing plants for battery systems, the same applies: no C-type standard exists yet. The supervisory authorities are also having problems evaluating the technology, which can lead to discussions and retrofitting when the plant is already in operation. 

 Added to this, the current generation of battery systems have been designed and optimized for their use in vehicles but not for ease of recycling. Anyone recycling batteries today is faced, for example, with seemingly simple questions: How do I open the battery? What cell chemistry does it contain? What is its electrical state? What has the battery 'gone through'? The collection, transport, discharging, disassembly and material separation of battery systems as a whole pose particular challenges. Policy guidelines can help in some areas. In any case, the technology continues to advance. While current recycling processes can only recycle approx. 50 percent of the materials compared to the theoretically possible 96 percent, new methods are already achieving a recycling ratio of over 90 percent. 

Andreas Centner: In the EU, this issue has been recognized and the EU Battery Regulation (EU) 2023/1542, which came into force on February 18, 2024, promotes among other things the collection, re-use and recycling of batteries. The regulation sets clear recycling efficiency goals and fosters the use of recycled materials in batteries to promote sustainability. In addition, from February 2027 certain battery types need to be equipped with a digital battery pass that comes with a QR code and provides comprehensive information about the battery. This should, in future, resolve the issues and challenges in current recycling practice that Ulrich Hochrein referred to in such a way that the recycling processes will become more technically appropriate and safe.

How do you think battery manufacturing will develop in the next few years? Do you foresee any particular challenges, and what does the European battery industry need to do to survive against the market leaders, including globally? 

Ulrich Hochrein: While the trend towards E-mobility may have currently weakened, it will pick up sharply in the long-term especially since battery storage technologies are cheaper than ever. Consider the area of large energy storage systems: while one kilowatt-hour of battery storage still cost 1,200 euros in 2010, it is currently 130 to 120 euros and tending towards 90 euros in about five years time. This means that more manufacturing and recycling facilities for battery systems will be built to cover the future demand. It is also to be expected that new battery concepts and new cell chemistries will emerge. This will have a big impact on the performance and safety of plants and systems. Statutory regulations, perhaps also C-type standards, are certain to be created and will standardize many aspects. Overall, Germany and Europe will need to produce better, more sustainably and more intelligently in order to achieve greater relevance in the global battery competition.

Andreas Centner: The German and the European battery industry is competing with the global market leaders, in particular from China, South Korea and the USA. To remain competitive long-term and ensure technological and economic sovereignty, it needs to act in a targeted manner in several key areas. SICK already offers solutions for several of these. This includes products and systems relating to automation and safety technology, as required, for example, for the establishment and expansion of further production and recycling capacities. With intelligent sensors and controllers, SICK enables efficient manufacturing using Industry 4.0 technologies, while our identification technologies can also be used for the traceability of battery systems. If, through strategic partnerships, the battery industry succeeds in building up reliable supply chains, intensifying its research and development efforts and thereby scaling pilot and demonstration projects more quickly, and leveraging regulation and sustainability as strengths, the prospects for Germany and Europe in the global battery competition are very good. The sector has no direct influence on the required reduction in energy prices and securing of infrastructure. These are external factors that require political decisions.

How and why are EDAG and SICK collaborating so successfully as business partners? 

Ulrich Hochrein: I've been with EDAG for 35 years now and for the first ten years I was commissioning systems in the field. During all those years, my colleagues and I at EDAG have experienced good support, fast assistance with technical difficulties, direct service, and honest communication from SICK. The products, in particular, are properly documented, which is an enormous help when planning complex systems. 

Meik Kettinger: Our collaboration has been a partnership of equals for many years now. Each benefits from the specialist knowledge of the other. Our joint customers are also aware of this, of course, when we implement projects with them. EDAG and SICK deliver a solution like from a single source. This is the key requirement for also jointly receiving the order.