Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New technique to improve quality control of lithium-ion batteries

10.05.2013
Researchers have created a new tool to detect flaws in lithium-ion batteries as they are being manufactured, a step toward reducing defects and inconsistencies in the thickness of electrodes that affect battery life and reliability.
The electrodes, called anodes and cathodes, are the building blocks of powerful battery arrays like those used in electric and hybrid vehicles. They are copper on one side and coated with a black compound to store lithium on the other. Lithium ions travel from the anode to the cathode while the battery is being charged and in the reverse direction when discharging energy.

The material expands as lithium ions travel into it, and this expansion and contraction causes mechanical stresses that can eventually damage a battery and reduce its lifetime, said Douglas Adams, Kenninger Professor of Mechanical Engineering and director of the Purdue Center for Systems Integrity.

The coating is a complex mixture of carbon, particulates that store lithium, chemical binders and carbon black. The quality of the electrodes depends on this "battery paint" being applied with uniform composition and thickness.

"A key challenge is to be able to rapidly and accurately sense the quality of the battery paint," said James Caruthers, Reilly Professor of Chemical Engineering and co-inventor of the new sensing technology.

The Purdue researchers have developed a system that uses a flashbulb-like heat source and a thermal camera to read how heat travels through the electrodes. The "flash thermography measurement" takes less than a second and reveals differences in thickness and composition.

"This technique represents a practical quality-control method for lithium-ion batteries," Adams said. "The ultimate aim is to improve the reliability of these batteries."

Findings are detailed in a research paper being presented during the 2013 annual meeting of the Society for Experimental Mechanics, which is June 3-5 in Lombard, Ill. The paper was written by doctoral students Nathan Sharp, Peter O'Regan, Anand David and Mark Suchomel, and Adams and Caruthers.

The method uses a flashing xenon bulb to heat the copper side of the electrode, and an infrared camera reads the heat signature on the black side, producing a thermal image.

The researchers found that the viscous compound is sometimes spread unevenly, producing a wavelike pattern of streaks that could impact performance. Findings show the technology also is able to detect subtle differences in the ratio of carbon black to the polymer binder, which could be useful in quality control.

The technique also has revealed various flaws, such as scratches and air bubbles, as well as contaminants and differences in thickness, factors that could affect battery performance and reliability.

"We showed that we can sense these differences in thickness by looking at the differences in temperature," Adams said. "When there is a thickness difference of 4 percent, we saw a 4.8 percent rise in temperature from one part of the electrode to another. For 10 percent, the temperature was 9.2 percent higher, and for 17 percent it was 19.2 percent higher."

The thermal imaging process is ideal for a manufacturing line because it is fast and accurate and can detect flaws prior to the assembly of the anode and cathodes into a working battery.

"For example, if I see a difference in temperature of more than 1 degree, I can flag that electrode right on the manufacturing floor," Adams said. "The real benefit, we think, is not just finding flaws but also being able to fix them on the spot."

Purdue has applied for a patent on the technique.

Writer: Emil Venere, 765-494-4709, venere@purdue.edu

Sources: Douglas E. Adams, 765-449-4249, deadams@purdue.edu

James Caruthers, 756-494-6625, caruthers@purdue.edu

ABSTRACT
Lithium-ion Battery Electrode Inspection Using Flash Thermography

Nathan Sharp, Douglas Adams, James Caruthers, Peter O'Regan, Anand David, Mark Suchomel

Purdue University

Nonuniformity in lithium-ion battery electrode thickness or composition can lead to reduced performance and longevity. Currently battery manufacturers have no way to quickly and accurately assess electrode quality during the manufacturing process. A finite element heat transfer model based on heat conduction equations has been developed to provide theoretical justification and insight. The model shows that a heat pulse to the back of a current collector will conduct through the electrode in such a way that spatial changes in thickness or material properties will have different transient temperature responses and that the response difference will be maximum around 3-10 ms after the flash occurs. Experiments were run to test the effectiveness of the flash thermography method for detecting several different types of defects. Gross defects such as contaminants, scratches and bubbles were shown to be easily detectable. Thickness variation was also tested and shown to have a sensitivity of 1 percent change in temperature for 1 percent change in thickness. Thickness differences were shown to be detectable in at least as small as 4 percent thickness difference. Composition differences were also tested, looking at the difference in relative percentage of active material, carbon black, and PVDF. Not enough data was taken to quantify the sensitivities of composition changes, but testing was shown to be able to detect composition differences. Thermography testing also showed a wavelike thickness pattern occurring, which has not previously been reported on battery electrodes. Comparison with a commercially purchased electrode showed that this phenomenon exists on the commercial electrode as well. Further testing needs to be conducted to determine the cause of this phenomenon, but it is hypothesized that is due either to a vibration in the coater blade or a nonlinear fluid interaction of the electrode slurry. Results and analysis show that flash thermography is a viable method to detect variability and defects in battery electrodes during the manufacturing process.

Emil Venere | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Power and Electrical Engineering:

nachricht Researchers use light to remotely control curvature of plastics
23.03.2017 | North Carolina State University

nachricht TU Graz researchers show that enzyme function inhibits battery ageing
21.03.2017 | Technische Universität Graz

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>