Why the quality of the binder solution is so important?

Since the binder is mixed with an active material, a conductive material, etc. in the form of a binder solution dissolved in a predetermined solvent, the solution quality of the binder affects the quality of an electrode slurry or an electrode. For example, if the solution quality of a binder such as CMC or PVDF is not good, various problems such as increase in slurry viscosity, surface defect of electrode coating, drop in electrode adhesion, etc. may be caused. The solution quality of the binder depends on the degree of minimization of the insolubles in the binder solution.

How to check out the insoluble traditionally?

Heretofore, insoluble matter of a binder solution has been detected simply by observing the binder not completely dissolved in the solution, or after applying a binder solution to an OHP film with a blade of a certain thickness by counting the number of foreign matters ( insolubles) on the film with the naked eye. However, with this method, it is difficult to assess the overall quality of the solution due to the small amount of sample. In addition, the measuring accuracy is not high since foreign substances can be introduced which cannot be distinguished from the insoluble substances. In addition, there may be a significant error due to the appraisal with the naked eye depending on the appraiser. Finally, only the number of insolubles can be measured, while the content of insolubles cannot be evaluated quantitatively.

How is the information on the content of insoluble matter influencing the quality of electrode?

In the case where there is no information on the content of insoluble matter of the binder solution, particularly no information on the content depending on the size, quality characteristics such as the surface defect of the electrode of a secondary battery may vary depending on the properties, sizes, etc. of the insolubles vary even when using binder solutions obtained by dissolving the same binder content in a solvent. It is then not possible to ensure a constant quality of the electrode and it becomes difficult to improve the quality of the electrode.

-The properties, sizes etc. of the insoluble are different even when using this binder solution which is obtained by dissolving the same binder in the same solvent.

-The different properties, sizes etc. of the insoluble above can cause different quality characteristics such as the surface defect of the electrode.

-The size information of the insoluble is crucial.

-To ensure the constant quality and improve the quality of electrodes, the information of the content of insoluble matter is very important.

 

LGES’ solution for the information of the content of insoluble matter (Korean Patent Publication No. 10-2017-0111722)

Accordingly, there is a need for a technology for producing a binder solution for checking the content of insolubles in a binder solution for a secondary battery electrode and improving surface defects of a secondary battery electrode, and a technology for producing such an electrode slurry.

 

Source link:

https://patents.google.com/patent/DE202022100750U1/en?q=silicon+electrode+binder&assignee=LG+Energy+Solution%2c+Ltd.%2c&sort=new