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Posted: Aug 30, 2011
Development of X-Ray Particle Inspection System for Lithium Ion Batteries
(Nanowerk News) Measurement and analysis instrument manufacturer SII NanoTechnology Inc. (SIINT) a 100% subsidiary of Seiko Instruments Inc. (SII), successfully developed the X-ray Inspection system which enables the detection of the metal particles about 20µm in diameter contained in the fuel cell electrode and the lithium ion rechargeable battery electrode in few minutes and the elemental analysis automatically. The prototype will be released at JAIMA EXPO 2011/ SIS 2011, the biggest trade show of analytical instrument in Japan, at Makuhari Messe on September 7th to 9th.
X-Ray Particle Inspection System (Prototype)
Contamination of the metal particles in the fuel cell and the lithium ion rechargeable batteries causes the decrease of the production yield and the battery lifetime. Especially the contamination in the lithium ion rechargeable batteries causes the heat and the fire in the worst case. Contamination of the metal particles has to be avoided due to the large volume of the batteries used in the electric vehicle, the hybrid car, and the residence. Therefore the most of the battery manufacturers perform the complex failure analysis.
Contamination is caused by the materials such as the active materials *2 and the separators *3, and through the manufacturing process of coating.
In the conventional method the failure analysis is performed to assume how the disassembled failure battery is contaminated by specifying the target elements using the Scanning Electron Microscope or the fluorescent X-ray analyzer after identifying the location of the metal particles in the disassembled failure battery using the X-ray CT system or the optical microscopes. However, its limited performance caused the difficulty in detecting the metal particles less than or equal to 20µm in diameter and the long detection time. Furthermore, there was a problem that the identified location was lost due to the elemental analysis of the detected particles was performed by other systems.
SII NanoTechnology Inc. developed the world's first *1 X-ray particle inspection system which enables the inspection and the analysis of the metal particles about 20µm in diameter using the technologies of metal particle detection by X-Ray Imaging and the fluorescent X-ray analysis.
This system automatically delivers the X-Ray Imaging, the detection of the metal particles, and the elemental analysis only by setting sample such as the electrode, the separators, and the active material in the pan, selecting the detection procedure, and starting measurement. As a result of the analysis the number of metal particles, each composition, size, and the images by optical microscope are provided. Due to the results can be obtained automatically without sample preparation, the failure analysis and the sampling inspection can be performed easily.
Key Features of the X-Ray Particle Inspection System
(1) Only Few Minutes to Detect the Particles About 20um in Diameter from the A4-Size Sample
For example, it took more than several hours to by conventional X-ray CT system to detect the metal particles about 20µm in diameter from the A4-size battery electrodes *1. SII NanoTechnology Inc. successfully increased the detection speed by more than 100 times compared with the conventional speed by greatly reduced imaging time using newly developed detector, new X-ray tube, and new image processing technology. This system enables to finish imaging in 3 to 6 minutes and to detect the particles about 20um in diameter automatically.
Elemental analysis is performed automatically using fluorescence X-ray method to the detected metal particles.
Equipped with the unique Focused X-ray Optics, the elemental identification speed for the metal particles about 20µm in diameter increased by around 10 times as fast as conventional systems.
(3) Higher Efficiency by All-in-one System
X-ray imaging unit, the fluorescent X-ray analyzer, and the optical microscope are integrated into this system and they are linked to provide the results fully automatically. Thus the operator can obtain the measurement results by setting the sample only which result in the significant higher working efficiency.
*1: According to our own research
*2: Active material: Material which captures and releases electrons by a chemical reaction
*3: Separator: Film with innumerable holes (Polyethylene: PE or polypropylene: PP) which insulates a positive and negative electrode electrically.