WEBINAR | From Infrastructure to Impact: EM & Micro-CT in Materials Core Facilities

CT-Based Inspection of Cylindrical Battery Cells Using Tescan UniTOM XL

X-ray microtomography provides a non-destructive view into internal cell architecture — supporting performance validation, design optimization, and safety-critical QA.

hero
hero
Unlocked content

Why Internal Construction Matters in Cylindrical Cell Performance and Safety 

High-capacity cylindrical lithium-ion batteries — such as 26650 formats — are widely used in electric vehicles, energy storage systems, and consumer electronics. Their reliability hinges on precise internal structure: electrode alignment, tab placement, cap integrity, and mechanical symmetry.

This study, conducted with Dragonfly Energy Corp., demonstrates how Tescan UniTOM XL micro-CT enables full-volume, non-destructive imaging of assembled cylindrical cells. The resulting data provides actionable insight into features that affect performance, thermal behavior, and safety — without disassembling the battery.

Why Study 26650 Cells

with Tescan Micro-CT

01
Root of the Problem

What Makes Internal Geometry Critical in 26650 Cells

In cylindrical cells, structural precision directly influences thermal behavior, charge transport, and long-term durability. Electrode tabs must be correctly placed to minimize resistance and avoid current hotspots. The anode overhang — an intentional extension beyond the cathode edge — must be within strict tolerances to avoid lithium plating or incomplete charge distribution.

Cap components such as the current interrupt device (CID) and positive temperature coefficient (PTC) are the last line of defense in runaway scenarios. If any of these features are poorly manufactured or misaligned, they can compromise the entire cell. However, once a battery is sealed, these details are hidden — unless inspected by a non-destructive method like micro-CT.

02
Materials and Methods

Full-Cell Micro-CT with Structural Segmentation

A commercial 26650 cylindrical lithium-ion cell was scanned at high spatial resolution using the Tescan UniTOM XL system. Initial 2D slices captured the cell cap and sidewall for external evaluation. Full 3D reconstructions were carried out, with segmentation of key internal structures — including the jellyroll electrodes, tab connections, casing, and safety components in the cap.

Anode overhang was measured directly from the image data, and tab geometry was evaluated for symmetry, alignment, and position within the jellyroll. Additional segmentations highlighted the CID and PTC elements for safety device analysis.

03
Results and Discussion

Detecting Cap Damage, Tab Misalignment, and Electrode Offset

The 3D reconstructions exposed several structural features of interest:

01
Cap Inspection: A corroded cap was easily identified through subtle grayscale differences. Component identification within the cap showed the presence and placement of internal safety elements.
02
Tab Configuration: The tab layout inside the jellyroll was clearly resolved. Improperly folded or asymmetrically placed tabs were detected — features that can alter charge distribution or lead to overheating.
03
Anode Overhang: Overhang length was quantified along the jellyroll edge. Misalignment of electrode layers — a factor known to promote lithium plating — was observed in one sample.
04
Segmentation Output: Components were digitally labeled, making the data ready for comparison with design specifications or for import into modeling software.

These findings support the use of micro-CT in both development and quality assurance — allowing battery makers to spot construction issues early, optimize design tolerances, and verify safety-critical geometry without destructive testing.

GET IN Touch

Contact us

Get the most out of Tescan

This is more than information; it's an advantage. We've compiled our technical whitepapers, detailed product flyers, and on-demand webinars to provide you with the knowledge that makes a real difference. Sign up now to access the insights you need to make an impact.

Tescan Instruments & Technology

Used in This Workflow

Tescan UniTOM XL

Tescan UniTOM XL combines speed, resolution, and large sample volume capacity, enabling complete, non-invasive imaging of cylindrical, prismatic, and pouch cells. 

  • Supports high-resolution scans of full battery cells and modules

  • Fast reconstruction of internal components with no sectioning required

  • Suitable for inspection of tab structure, cap assembly, and layer alignment

  • Seamless workflow with segmentation and analysis in VGSTUDIO MAX 
MICRO_UniTOM_XL_1-2

GET IN Touch

Contact us

map

Where can you find us:

Tescan Brno
Libušina třída 21
623 00 Brno
Czech Republic

info@Tescan.com 

130405923 us US 37.09024 -95.712891 25.3575 29.349345 20.67957527 42.082797 39.91384763 -33.693421 13.93320106 3.039986586 31.997988 38.050985 47.579533 48.1485965 58.375799 54.663142 19.195447 56.975106 50.493053 45.868592 10.79556993 44.35660598 43.2371604 55.536415 14.557577179752773 32.100937 -6.116829 -6.212299277967318 23.7104 -33.471062 31.998740087 -23.69149395 43.462349 51.529848 49.1893523 49.197486 25.072375 31.075811 1.299027 40.676979 52.30150662 51.013813 35.684121 37.479653 52.246622 40.581349 39.911632 -26.1811371 41.818215 33.429928

No distributors found.