EV Batteries – The Critical Role of Mechanical Testing

Mechanical and multifunctional tests are not only tools for quality control, but also the key to innovation. They provide crucial insights that enhance materials and processes, thereby driving advancements in battery technology.

• Optimize production/reduce costs
  In the coming years, costs can be reduced primarily by increasing the energy density in the cells, reducing the amount of materials and raw materials and the resulting processing costs, and by increasing efficiency in the production of the cells. Materials testing enhances our understanding, enabling further development and optimal utilization. This can significantly reduce the high costs associated with rejects.
• Improving reach and service life
  In addition to the further optimization of lithium-ion batteries in terms of service life/reach, the industry is also focusing on another battery technology in the future. All major manufacturers are investing in research activities for solid-state battery technology. However, there are still some challenges here, from changing the volume of the anode to adapting production, as only 40 percent of the existing machines and processes can continue to be used. In addition, solid-state batteries require high-pressure conditions for the best possible contact. The mechanical characterization of cell behavior is therefore of great importance.
• Increasing safety
  To be able to predict the behavior of batteries in extreme situations, battery abuse tests and multiphysics tests are indispensable in battery development. These tests require extensive safety measures and are extremely complex and critical to carry out.
  

Battery systems are crucial to electric vehicles, significantly impacting performance and representing the largest portion of the total cost. Mechanical and multifunctional testing at various levels—from cell components to complete battery packs—is essential to ensure safety, performance and reliability.

• Testing of raw materials and cell components: The production of battery cells encompasses various stages, including coating metal foils and stacking and assembling the individual components. Tensile tests on films or evaluating the adhesive strength of electrode coatings are therefore crucial to ensure that each component meets quality standards.
• Testing of cells: Battery cells are subjected to mechanical, electrical and thermal tests—often simultaneously. For example, the cells are subjected to mechanical compression at controlled temperatures while they are being charged and discharged in order to obtain information about their behavior at different pressures and temperatures.
• The battery system: At the system level—for modules or packs—the focus is on structural assessments such as the strength of brackets, bonded joints and weld seams. Quasi-static tensile or shear tensile tests are carried out.
• Battery abuse testing : In view of the risk of fire and explosion, battery abuse tests are crucial for evaluating the behavior of a battery under extreme conditions. Tests such as nail penetration, crush tests and temperature cycles help to identify weak points and improve overall safety. Here, the demands on the accuracy of the testing systems are constantly increasing with further technological developments.

The mechanical tests are an indispensable part of battery development. From research to production and quality assurance, they play a key role in developing more powerful, safer and longer-lasting batteries for the next step towards a CO2-neutral future.