Surface roughness and chemistry of battery foil, key to better battery

During battery manufacturing, thin metallic foils are coated with a slurry that contain binders, conductive material and the active material. The role of the foil is to both mechanically act as a substrate for the slurry and as a conductor of the electricity to the outside of the battery. The foil does not add to the capacity of the battery which is why it is made as thin as possible, about 12 - 18 micrometre is common. This put fairly high demands on the mechanical properties of the foil and the interactions between slurry and foil.

By increasing the surface roughness the foil can increase the surface area without increasing the size of the foil. This has potential to both increase the adhesion of the slurry to the foil and to reduce the contact resistance in the interface. This could be achieved in an enivormentally friendly manner by laser techniques or during rolling by utilizing patterned rollers.

The adhesion of the slurry to the foil is a challenge for many batteries, especially newer more environmentally and worker friendly chemistries. Atmospheric plasma is a well tested technique the improve wettability and adhesion, in for example adhesive bonding. It also has promising potential to improve the wettability and adhesion of the slurry to surface activated battery foils.