The technical hurdle of 5μm ultra-thin wet -Lithium - Ion Battery Equipment

The "technical hurdle" of 5μm ultra-thin wet diaphragm -Lithium - Ion Battery Equipment

With the continuous improvement of battery capacity and performance requirements in the lithium battery market, more and more functional separator coatings have emerged, and the ultra-thin trend of lithium battery separators has become more and more obvious. In the effective space inside the battery, the ultra-thin separator can give more space for the active material of the pole piece, and can carry more functional coatings at the same time.

The market demand of 5μm ultra-thin wet diaphragm in the high-end 3C digital field has also emerged as the times require.

As one of the highest technical barriers in lithium battery materials, the technical difficulties of separators lie in the engineering technology of pore making, matrix materials, and manufacturing equipment. Ultra-thin diaphragms are significantly different from thick films in terms of processing equipment, processing technology and material selection.

High-tech lithium battery technology and applications understand that it is the most important technical difficulty for ultra-thin films to ensure superior permeability without losing the mechanical strength characteristics of the product in practical aspects, and to ensure the safety, isolation performance and consistency of the product.

Therefore, how to ensure the puncture resistance, mechanical strength and isolation properties of the separator has also become a major technical challenge for 5 μm ultra-thin films. Regarding the wet manufacturing process, the extrusion mixing process of resin materials and additives and the stretching process test the understanding and innovation of the diaphragm company's technical process. At the same time, the stable film formation of the ultra-thin film process, the flatness of the ultra-thin film product, and the control of swaying and waves are also a major difficulty in process control.(Lithium - Ion Battery Equipment)

At present, more than half of the domestic market of 5μm ultra-thin film products is still monopolized by import companies, and representative companies include Asahi Kasei, South Korea's SK, etc. The important reason is that the development of domestic ultra-thin films is later than that of foreign countries, the habit of using products, doubts about domestic products, and the designation of downstream manufacturers. It is understood that the puncture strength of the imported diaphragm is about 250GF, and the bidirectional tensile strength is about 2000kgf/cm2.

As a very fine pore-forming material, each step of the process requires repeated and a lot of time verification. To achieve large-scale mass production, a large amount of data verification and accumulation is required. The most important thing is that it needs to be verified by a wide range of applications in the downstream market.

High-tech lithium battery technology and applications learned that the performance indicators that the downstream market is most concerned about with 5μm ultra-thin films are the consistency of pores. At present, high-end manufacturers require diaphragm manufacturers to describe the uniform distribution of pores during processing; second, the entire The consistency of macroscopic physical indicators, such as the fluctuation of physical indicators in the vertical and horizontal directions, etc.; the third is the processability of the diaphragm, the smoothness of the diaphragm, the consistency of thickness, and the degree of curling after the coating is applied.

It is gratifying that some domestic diaphragm companies have already broken the technical bottleneck of ultra-thin films. The puncture strength of ultra-thin film products has reached 320GF, the longitudinal tensile strength has reached 3400kgf/cm2, and the transverse direction has reached 2000kgf/cm2. And achieve a stable market batch supply.

At present, due to the high cost of diaphragms for 3C digital batteries and the technological breakthroughs of domestic diaphragm manufacturers in 5μm ultra-thin films, the domestic market demand for localized replacement of 5μm ultra-thin films has become increasingly urgent.

Industry analysts believe that, judging from the demand for domestically produced 5μm ultra-thin films in the fourth quarter of 2018, the replacement of domestically produced ultra-thin films in 2019 will gradually become popular and common. 2019 is also expected to be the first year of large-scale localization of 5μm ultra-thin films.



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