Nonlinear Acoustic Shear Wave Detection of Zero Gap Kissing Bonds in Encapsulated Packs
Nonlinear acoustic shear wave harmonic detection resolves zero gap kissing bonds in encapsulated battery packs by measuring contact acoustic nonlinearity.
Elastomeric Couplant
Meaning
A dry, flexible synthetic material used to transmit acoustic energy between an ultrasonic transducer and a test object eliminates the need for liquid or gel interfaces during battery inspection. An elastomeric couplant is placed under pressure between the sensor head and the battery cell surface to expel air. This dry coupling method avoids contaminating the cell terminals or casing with water, oil, or glycol.
Acoustic Transmission
High-frequency sound waves cannot travel through air gaps due to the extreme difference in density between the transducer and the solid cell casing. The dry polymer sheet deforms under low clamping pressure to fill the microscopic surface roughness of both the sensor and the cell. This physical deformation creates a continuous path for the ultrasonic energy to pass into the cell with minimal signal loss.
Consistent acoustic transmission is achieved without leaving any residue.
Inspection Advantage
Using a dry polymer interface speeds up the testing process on high-speed automated assembly lines. Liquid couplants require a subsequent cleaning step to prevent corrosion of the aluminum and copper electrical contacts. In contrast, the flexible elastomer can be reused for thousands of cycles and leaves the cell surface completely clean.
This allows the testing station to be integrated directly into the inline quality control flow.
Sourcing Consideration
Procurement teams choose these materials based on their durability and chemical resistance to electrolyte vapors. Purchasing high-quality polymer pads reduces the downtime of automated inspection lines. These cost considerations are weighed against the expense of liquid cleaning systems.