Author: Dr. Hitoshi Nakamura
Lithium-ion battery degradation usually starts at the anode. Sanyo was the first to use Carboxymethyl Cellulose (CMC) in anode slurry. At first, the life of the battery was short, and this was due to lumps. When there are lumps, the area is electrically insulated, so it is easy for SEI to develop abnormally, which is the starting point for triggering degradation. In addition, dendrites can develop and cause fires.
I think this is one of the reasons why batteries from not so good manufacturers cause fires.
The CMC I use is dedicated for lithium-ion batteries and has few gel balls, but an electron microscope shows lumps of about 10-30 microns. This level is fine, but the risk increases when it exceeds 100 microns.
Some filters are industrially effective, so it doesn’t seem to be much of a problem now.
I am a Japanese battery engineer with about 30 years of experience in the field of energy storage.
My work has covered a wide range of areas, including cathode and anode material development, cell design, cell manufacturing processes, pack and module engineering for EVs, safety evaluation, life estimation, and simulation technologies. I have also worked on safety test standards and contributed to discussions in international standardization.
Book: Li-ion Batteries, RSC Foundations