What is the development direction of lithium battery water-based adhesives?

The lithium battery was born in the 1950s and has undergone many changes. At any time, there is a battery binder in the lithium battery that accounts for less than 1-2%, which plays an important role, and often because of certain characteristics of the binder polymer, the battery performance is brought to the attention, unexpected influence.

With the increasing demand and expectation of lithium batteries at the application end, the future development direction of lithium battery water-based adhesives is urgently required for technical development prediction, and technical reserves are advanced in advance, and development also pays more attention to technological innovation to cope with future lithium batteries demand. In this regard, the JSR binder development and application team has conducted continuous research on the properties, structure and distribution of binder polymer polymers.

The ability to leverage elastomer/emulsion technology is key to achieving the demand for binders for lithium-ion batteries. From the perspective of the industry, there are generally some basic application requirements for the performance of the binder in lithium batteries.

- Excellent adhesion to active materials and metals

-Anti-electrolyte chemical stability

- Stability of the colloid in the slurry

-Good processing performance

After long-term research, it is found that the water-based binder can directly affect the performance of the lithium battery in addition to the basic application requirements of the above-mentioned lithium battery. The range of influence includes bond strength, migration inhibition (process speed), internal resistance, expansion inhibition, and cycle characteristics.

Long-term research on the above-mentioned influence range JSR has shown that the effect of the binder on the battery performance can be effectively controlled by the polymer properties and particle design. This will be discussed in detail below.

Effect on bond strength: By controlling the structure and molecular weight of the polymer, the ductility and strength of the binder inside the lithium battery can be controlled. The surface functional group modification of the binder particles can affect the distribution position of the binder in the active material (the effective aggregation of the binder and the contact site of the active material). Faced with different active substances can affect the distribution and increase the bond strength.

Impact on migration inhibition: The binder is an organic chemical that is suspended in water as a liquid emulsion. It is added to the slurry and coated on the pole piece. In order to improve the production efficiency, the drying temperature is generally increased (the conveying speed is fast) to meet the production. When the temperature is high, the evaporation rate of the water is faster, so the suspended binder is used, will quickly migrate to the surface of the pole piece, resulting in the lack of binder at the Cu interface, especially in the case of rolling, causing sticking or de-powdering, material loss and so on.

JSR polymerization technology starts from the TRD series of binder products, adapts to market demand, and contributes to the inhibition of migration from polymerization means.

Effect on internal resistance: After the binder particles are dried in the pole piece, the electrolyte will swell in the battery, and excessive swelling will affect the e-electron transfer, resulting in an increase in internal resistance. By controlling the affinity of the polymer and the electrolyte, the internal resistance can be prevented to a certain extent.

The effect on the expansion of the battery: the monomer component on the surface of the binder particles is controlled and surface modified to achieve excellent adhesion to the active material and the metal, chemical stability against the electrolyte, and stability of the colloid in the slurry sex. In addition to controlling the ductility and strength of the binder itself, the purpose of suppressing electrode expansion can be achieved.

Effect on cycle performance: The electrolyte resistance of the binder particles is improved, the strength and elasticity are reduced with time, and the adhesion can be secured for a long time. Especially in the case of long-term circulation, the test of the elasticity and durability of the adhesive can be more and more manifested.

Conclusion: The development of lithium-ion batteries is constantly applied to high energy density, high output, and adapt to a wider range of temperature requirements. The application of positive electrode continuously develops from NMC to high Ni system or NCA system, and the demand for negative electrode capability matching needs more and more urgent for Si application.

Many factors of the binder have a direct influence on the electrode. In addition, in the fast-paced moment, the demand for fast charging (large rate charging) is increasing. The above-mentioned strength, internal resistance, migration, etc. all have many factors affecting the lithium evolution of the active material. For the future development and application of battery cells, the JSR R&D team will continue to develop the future development at the forefront of development directional binder.

The page contains the contents of the machine translation.