Conductive adhesive bonding for electrical connections in battery packs (CABEL)

Important results from the project

The objectives were well met. Electrically conductive adhesives provided exceptional mechanical strength, surpassing laser welded joints. Initial electrical resistance was also comparable to welding, only slightly higher. However, we discovered that silver-filled adhesives caused galvanic corrosion on aluminum over time. As an important side note, we therefore developed a new nickel-based adhesive that showed much more stable performance. Spot welding was also identified as a good repair method.

Expected long term effects

The project provides critical guidance to the industry: silver-filled ECAs do not work long-term on aluminum in these applications. This directs future materials research towards new filler materials, such as the promising nickel-based adhesive, to eliminate corrosion. At the same time, single-sided spot welding is expected to facilitate low-cost repairs. Taken together, these insights enable more robust batteries and significantly increase the circularity of the industry, including repair.

Approach and implementation

The consortium (RISE, Scania, Biesterfeld) divided the work into three packages. WP1 performed rigorous tests (4-point measurement, tensile test, aging) to compare ECA with laser welding. WP2 mapped new materials and developed the successful nickel-based adhesive formulation. WP3 handled project management. The approach combined battery design, technical research and materials knowledge very effectively to answer the project´s questions.