Description
1. Significance of Volume Swelling Testing for Cylindrical Battery
During the charge and discharge processes of lithium ion batteries, as lithium ions intercalate and deintercalate into the positive and negative electrode materials, the cell undergoes reversible expansion and contraction. Concurrently, various side reactions occur, such as particle fracture, SEI membrane rupture, cell deformation, lithium plating, gas evolution, etc., resulting in irreversible deformation.
2. Limitations of Existing Methods
Curently, there are several methods available to characterize the expansion of cylindrical batteries, such as vernier calipers cordinate measuring machines, presure fims, strain gauges, and imaging analysis technigues (including CT scanning, neutron imaing, X-ray, ultrasound etc.) However, these methods suer from low accuracy, inability to conduct in-situ testing, and inability to acurately and comprehensively describe the expansion behavior of cylindrical batteries.
3. Application Scenarios
Material Evaluation
- Assessment of modification performance for silicon-based anodes, high-nickel ternary, lithium-rich manganese-based, and other active materials used in cylindrical cells.
Structural Evaluation
- Evaluation of cylindrical cell core structures across different dimensions, wound jelly-roll configurations, and casing rupture risk assessments.
Operational Condition Evaluation
- Characterization of multi-scenario operating conditions across varying temperatures, charge/discharge C-rates, and long-term storage behavior.
4. Working Principle
Optics-Based Battery Volumetric Imaging Technology
Based on optics-driven volumetric imaging technology, it enables real-time reconstruction of the battery surface 3D topography during charge-discharge cycling and precisely calculates deformation/volume changes.
- Opticallmaging+ 3D Reconstruction + Real-time Online Monitoring
- Non-contact, Non-destructive
- Single channel
- 25°C – 45°C temperature control
- Max supported current: 30A
5. Leading Technology
Applications
1. Application Case: Swelling Volum
1.1 Swelling Testing of cells with Different Silicon Contents
- 21700 Cell parameters: Sample 1-15%Sic ; Sample 2-10%Sic
- The formation volumetric swelling curves indicate that as the silicon content increases, the volume expansion during the formation process intensifies, and the peak corresponding to lithiation on the differential capacity ($dQ/dV$) curve becomes progressively higher.
1.2 Diameter Swelling Testing Under Different C-Rates
- Sample: 21700 NCM/Gr, 4.2 Ah
- Different C-Rates: 0.5C/1C/2C
- Conclusion: Different charging currents have a significant impact on thickness swelling.
1.3 Diameter Swelling testing of 4695 batteries
- Sample: 4695 NCM/Gr, 33Ah
- C-Rates: 0.1C
- Conclusion: During charge-discharge cycling, the maximum diameter expansion is approximately 50 μm, and the cylindrical cell exhibits non-uniform swelling behavior.
1.4 Diameter Swelling testing of 4680 batteries
- Sample: 4680 NCM/Gr, 30Ah
- C-Rates: 0.1C
- Conclusion: During charge-discharge cycling, the maximum diameter expansion is approximately 23 μm, and the cylindrical cell exhibits non-uniform swelling behavior.
2. Application Case: Swelling Force
- Test Scheme: After sealing the cylindrical cell into aluminum laminated film, in-situ swelling testing was conducted using the SWE series testing system.
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Mechanics Theory of Swelling: Based on the thick-walled cylinder shear stress theory, cell swelling is primarily driven by stresses in both the axial and circumferential (hoop) directions.
- In-Situ Characterization & Cell Optimization: By simulating the casing’s mechanical constraint on the cylindrical jelly-roll, this approach enables in-situ characterization of jelly-roll swelling force, facilitating the structural optimization and development of cylindrical cells.
Specifications
| CCS1100 | ||||
|---|---|---|---|---|
| Applicable Cells | Number of Channels | Optical Detection Resolution | Weight | Dimensions (W×D×H) |
| 18650, 21700, 4680 & 4695 Cylindrical Cells |
1 | 0.1 μm | 200 kg | 500 × 230 × 360 mm |
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IEST Cylindrical Battery In-Situ Volume Swelling Testing System
