Background: Pouch cells are a popular choice for lithium-ion battery applications due to their flexibility, lightweight design, and high energy density. The performance and reliability of pouch cells depend not only on the active materials but also on the materials used for all cell components.
Avocet Research Centre (ARC) was approached by a battery manufacturer seeking to optimise the tab materials to improve performance and reliability in conjunction with a specific pouch film.
The challenge was to identify and optimise the material and surface treatment combinations used for tab connections to ensure compatibility with the given pouch film while maximising performance and reliability.
Solution: the ARC team conducted comprehensive research and testing to identify the optimal polymer material, metal surface treatments, and sealing conditions for tab connections in conjunction with the specified pouch film. The solution involved a systematic approach, including:
- Material Screening: A wide range of polymer materials with varying compositions and properties were screened to identify candidates with the potential for high performance in tab connections.
- Compatibility Testing: Selected polymer candidates were evaluated for compatibility with the specified pouch film, considering factors such as adhesion, thermal stability, and chemical resistance.
- Adhesion Promotion: Surface treatments and adhesion promoters were applied to the metal surface (Al and Ni-plated Cu) to enhance bonding strength, adhesion and corrosion resistance.
- Mechanical Characterisation: The mechanical properties of the polymer materials, including tensile strength, flexibility, and fatigue resistance, were characterised to ensure suitability for tab connections in pouch cells.
- Performance Testing: Prototype tab connections using optimised polymer materials were subjected to performance testing under simulated operating conditions, including temperature cycling, electrolyte exposure, and mechanical stress.
Results: The selection of tab materials for optimised performance with the given pouch film led to several key results:
- Enhanced Adhesion: The selected polymer material exhibited excellent adhesion to both the tab metal and the pouch film, ensuring robust and reliable tab connections.
- Improved Mechanical Strength: The optimised polymer material demonstrated high mechanical strength and durability, withstanding mechanical stress and deformation during cell assembly and operation.
- Enhanced Thermal Stability: The polymer material exhibited good thermal stability, maintaining its integrity and adhesion properties over a wide temperature range.
- Compatibility and Reliability: dummy cells assembled with pouch film and tab connections using the optimised polymer material demonstrated improved compatibility and reliability, leading to enhanced performance and longevity.
Conclusion: The successful optimisation of material and surface treatment selection for tab performance with the given pouch film represents significant learning in battery technology and manufacturing. ARC’s expertise in polymer science and materials engineering has enabled the battery manufacturer to achieve higher performance, reliability, and compatibility in their pouch cell products.
By continuously innovating and optimising materials selection and manufacturing processes, ARC remains at the forefront of the energy storage industry, driving progress and enabling the widespread adoption of advanced battery technologies.