High Precision in Situ Structural Deflection Mapping in Commercial Battery Testing Tooling
In situ deflection mapping decouples test tooling flexure from cell swelling to restore true electrochemical capacity and volumetric degradation profiles.
Fiber Bragg Grating Strain Grid
Meaning
An array of optical fiber sensors embedded with periodic microstructures that reflect specific wavelengths of light provides high-resolution measurement of local deformation across a battery cell surface. This measuring system, called a fiber Bragg grating strain grid, tracks the mechanical expansion and localized swelling of battery cells in real time. It governs the collection of spatial strain data during rapid charging and discharging cycles.
The system’s application is limited to surfaces or interfaces where the optical fibers can be securely bonded or embedded without damaging the cell.
Sensor Implementation
Optical fibers are bonded to the cell surface or embedded within the module compression pads to capture strain profiles. During operation, the light reflected by the fiber Bragg grating strain grid shifts in wavelength as the cell expands or contracts, allowing precise calculation of local strain. Sourcing teams specify this technology for advanced development programs to validate finite element models of cell swelling.
This sensor setup provides highly accurate, electromagnetic-interference-free measurements in high-voltage environments.
Spatial Resolution
The density of the measurement points along the optical fiber determines the detail of the strain map. By using a multi-point fiber Bragg grating strain grid, engineers can detect highly localized swelling that would be missed by single-point displacement sensors. This detailed profiling is essential for identifying the onset of localized lithium plating or separator compression.
The resulting strain maps allow the development of more effective cell thermal and mechanical management systems.
Commercial Application
Automotive manufacturers leverage high-resolution strain data to select cell suppliers and validate module structural designs. Sourcing decisions are guided by the precise mechanical behavior recorded by these optical systems during environmental testing. By utilizing a fiber Bragg grating strain grid, laboratories can reduce the time required to qualify new cell designs.
This rapid validation accelerates the time-to-market for new electric vehicle platforms and ensures that the selected cells meet the highest standards of safety and mechanical reliability, protecting the manufacturer’s investment in new technology.