VITRONIC is testing a new inline inspection method that can detect particle contamination in the assembly of battery modules. Such contaminants can impair battery performance; they are also suspected of causing fires. With the inspection method, OEMs and suppliers ensure the Technical Cleanliness (TecSa) of the assemblies and increase product quality and safety. The inspection system could be used in the planned European Gigafactorys.

Technical Cleanliness as a requirement for electronic assemblies

As a result of recent political and business initiatives, European production of electric vehicles and batteries is increasing rapidly; dozens of manufacturing plants are planned or already under construction. In this context, Europeans follow their usual high quality and safety standards. Although Chinese manufacturers, for example, are often still pioneers in terms of technology, they apply much lower standards when it comes to quality assurance. Therefore, solutions for this cannot be adopted, but must be newly developed.

An important standard in battery cell assembly is the so-called Technical Cleanliness, abbreviated TecSa. The guideline of the ZVEI (German association of the electrical and digital industry) defines Technical Cleanliness as follows: no particles - metallic, non-metallic, fibers, etc. - may be present on components that could impair or prevent the function of the components or assemblies or the further manufacturing process.

The industry association TecSa has published two sets of rules for this purpose: VDA 19.1 (Testing of Technical Cleanliness - Particle contamination of functionally relevant automotive parts) and VDA 19.2 (Technical Cleanliness in assembly). The ISO 16232:2018 standard (Road vehicles - Cleanliness of components and systems) is the international equivalent.

Particle detection necessary before and after battery cell assembly

Since battery modules are not produced in a defined cleanroom environment, they can be contaminated with particles. These arise directly in the manufacturing process, for example through abrasion. They can also originate from the environment or from previous steps in the supply chain.

Dirt particles on battery modules can, among other things, penetrate the separator foil between two mounted battery cells. Current then flows between the cell housings, creating a short circuit. The current flow heats the cell. The heat can reduce the performance of the individual cells, destroy the cells or, in the worst case, ignite them.

Even if it is difficult to prove: Manufacturers assume that some fires of e-vehicles are due to particle contamination. The more batteries and vehicles are produced, the greater the likelihood of such incidents - and the pressure to develop solutions to minimize the risk.

Since, as mentioned, impurities cannot be prevented, reliable inspection methods are needed to detect them retrospectively. Ideally, testing is carried out at two process steps: during the manufacture of the battery cells (usually at the supplier) and during module assembly (usually at the vehicle manufacturer).

New inline system detects smallest particles

VITRONIC has developed a new inspection system for precisely this purpose: it allows battery cells and modules to be inspected for particle contamination directly in the assembly line. A first system is already in use and is being tested. 

The camera sensors used can detect smallest particles to ensure process reliability. The definition of the permissible particle size always considers required parameters such as accuracy, speed, and cost. The components are inspected directly in the line at two stations: first the sides of the individual battery cells and later the bottom of the entire assembled module. This reliably detects residual particles and ensures Technical Cleanliness in accordance with the industry standard.

With this inspection system, VITRONIC is expanding its portfolio of quality assurance solutions for e-vehicle production. The specialist for industrial image processing already offers further inspection systems for battery housings and cells.

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VITRONIC is a world leader in industrial machine vision. The owner-managed group of companies develops innovative products and customized solutions in the growth industries of automation, healthcare, photovoltaics, logistics automation, body scanning solutions, and traffic technology.

With over 35 years of experience, VITRONIC offers a unique portfolio of systems and software for image and sensor-based quality inspection, identification, traffic monitoring, and toll collection. Customers include renowned companies such as B.Braun, BMW, Daimler, DHL, UPS, Toll Collect, Fresenius, and Sanofi, as well as government agencies and public authorities.

VITRONIC systems play a major role in ensuring the highest levels of quality and efficiency in the production processes of the automobile, photovoltaic, and pharmaceutical industries.

In logistics centers and cargo airports worldwide, VITRONIC's Auto-ID solutions efficiently capture and integrate shipment data and ensure the transparent flow of packages.

In the traffic technology sector, VITRONIC offers high-performance technologies to increase road safety, improve traffic flow and secure tolling revenue.

Since its founding in 1984, VITRONIC has grown continuously, and currently has over 1,000 employees.  It is represented in four continents and in over 80 countries. VITRONIC supports its international customers through its subsidiaries in North America, Europe, Asia and Australia, as well as through a global network of sales and service partners.

VITRONIC systems are developed and manufactured at the company's headquarters in Wiesbaden, Germany. In 2020, the Group’s total revenue was 152,5 million Euros.

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