In Line Phased Array Inspection of Encapsulated Battery Structural Adhesives
Inline phased array testing maps structural adhesive wet-out and void formation through metal pack enclosures in real time at production line speeds.
Kiss Bond Detection
Meaning
Inspection challenge involves finding areas in an adhesive joint where the surfaces are in contact but have no structural strength. Using kiss bond detection prevents the use of battery packs that could fail under vibration or thermal expansion. It identifies a defect that often looks perfect during a visual check.
Acoustic Response
Transmission of sound through the interface changes when the bond is only mechanical rather than chemical. During kiss bond detection, ultrasonic waves are analyzed for subtle shifts in phase or frequency content. This technique requires sensitive equipment because the air gap in a kiss bond is effectively zero.
Failure Mechanism
Lack of adhesion at the molecular level means the joint cannot transfer loads between the two parts. If kiss bond detection is not performed, the weakened area may slowly unzip during the service life of the battery. This type of flaw is usually caused by surface contamination, such as oil or moisture, before the glue is applied.
Detecting it early in the manufacturing process saves the cost of a full recall and ensures the safety of the end user.
Inspection Limit
Capability of standard ultrasonic testing to find these flaws remains a topic of ongoing research in the aerospace and automotive sectors. Specialized kiss bond detection often involves non-linear acoustics or thermal imaging. The result is a pass or fail decision for the assembly.