KAIS

02.Plasma Surface Cleaning

Here at Kais, we take into account every minuscule detail that most battery makers overlook, but has a significant impact on the battery performance; one such example is plasma cleaning.

Plasma surface cleaning is a process that uses ionized gas to interact with a substrate to remove contamination and/or modify its surface. Plasma cleaning is a surface modification process and an etching process. Plasma cleansing applications are methods to promote adhesion between two items by decontamination of their interfacing surfaces, generating a modified surface condition, converting to higher surface energy, removing metal oxides by physical and/or chemical interaction.

This is especially important when manufacturing battery packs. A battery pack consists of two or more individual battery cells. The electrical connection between battery cells is typically achieved by a metal tab attached to each cell. Every connection is critical to the overall performance of the finished battery. Organic contaminants such as dirt and fingerprints or the presence of corrosion inhibiting agents like thin film coatings can contribute to low tensile strength joints in welding processes leading to poor adhesion, cracks, and porosity between the materials.

We perform plasma surface cleaning to every cell we process, cleaning the joint interface before welding to help ensure defect-free joints, which result in stronger welds, higher bonding yield, and improved battery performance.

Image of negative can surface with fingerprint (left) and after plasma cleaning (right).

 

Image of negative can surface with a significant amount of debris (left) and brighter, cleaner surface (right) to achieve stronger performance in pull test.

 

04.Atlas Copco Tightening Technologies

A loose joint in a battery pack may lead to fatal consequences. Both the integrity of the pack structure and the smooth conductivity of current flow are compromised by a loose joint, which causes the contact surface to decrease and electrical resistance to increase, leading to temperature rise and even ignition.

Kais makes sure that all screw threads are fit tight without deformation by using Atlas Copco tightening technique. This is done through two simultaneous loops: each screw joint is installed with precise torque and insertion angle, the toque seating is monitored in real-time and inputted into the seating control model, the model is then adjusted into the seating control strategy, which is applied to install and monitor the subsequent screw joints. Floating screws and striped joints are rejected and logged into our MES for future references.

ILLUSTRATION OF ATLAS COPCO TIGHTENING

06.Parylene Coating

Parylene Coating is the latest revolutionary technology in the field of ingress protection. It allows batteries to achieve IPX8 at the battery module level, meaning that the batteries can achieve full waterproof without the outer casing.

Parylene is a superior barrier layer that provides protection from moisture, corrosion, salt spray, solvents, and airborne contaminants. It is chemically inert, ultra-thin, pinhole-free, and conforms to components evenly and consistently. Combined with its unique molecular-level deposition, this high level of protection is achieved with 10% of the mass than spray or dip coatings.

This technology has seen few uses outside of the medical and aerospace industry due to its intimidating cost. With recent breakthroughs in parylene commercialization, this technology has become much more affordable, and it is quickly gaining popularity in various electronic industries. Today, Kais introduces the Parylene Coating technology to the battery pack industry.

Image of Parylene coating production line with a single batch capacity of 1,800 battery cells.