In the process of mixing, the small particles in the active material of the powder are easy to form dust pollution and dirty the working environment. At the end of feeding, a small amount of powdered active material remains in the packaging bag, which is also easy to stain the working environment.

　　In order to promote the progress of electrochemical reactions and reduce the resistance of electrode reactions, most lithium battery active materials use powder materials, including lithium battery cathode materials, anode materials, binder materials, and conductive materials. The active material of the lithium battery must be mixed with the corresponding solvent (such as NMP or water), stirred and dispersed (or dissolved) uniformly to form a slurry before it can be used in the manufacture of lithium batteries.

　　In the process of mixing pulp, the small particles in the active material of the powder are easy to form dust pollution and dirty the working environment. At the end of feeding, a small amount of powdered active material remains in the packaging bag, which is also easy to stain the working environment. As represented by lithium iron phosphate cathode materials and carbon nanotube conductive agents, dust pollution is particularly serious.

　　To this end, the author developed a completely dust-free and clean slurry technology for lithium battery powder active materials, and carried out the corresponding intellectual property protection layout. Through the process of mixing lithium battery powder active materials, the corresponding soluble packaging bags are used to package the powdered lithium battery active materials (the outer bag of the packaging bag is still a traditional aluminum-plastic film packaging bag, and the inner bag is soluble Packing bag), put the dissolvable packing bag and the lithium battery powder active material into the solvent used in the pulping process, so as to realize the clean pulping process and completely avoid dust pollution.

　　It is illustrated by a packaging bag made of PVDF. The size of the bag is 350mmx460mm, the thickness is 40 microns, the weight is 21.76g, and the volume is 8 liters. Such a bag will dissolve in NMP under stirring at room temperature for 5 minutes. If it is used to hold lithium iron phosphate material, it can hold about 6 kg, so the weight ratio of the bag to the lithium iron phosphate is 21.76/6000=0.36%. The common PVDF addition amount in the lithium iron phosphate positive electrode formulation is 2.5% relative to the positive electrode, which means that the amount of PVDF bag relative to the entire PVDF binder is only 14.4%, which has no significant change or influence on the entire bonding effect, and it will not Bring impurities, because PVDF packaging bags and adhesives are both PVDF materials. Even if the amount of PVDF adhesive is reduced to 1.5% relative to the lithium iron phosphate cathode in the formula, the amount of PVDF bag relative to the entire PVDF adhesive is only 24%. This soluble packaging bag actually only provides a simple film to prevent powder leakage. In production practice, the main packaging strength is provided by the aluminum-plastic film packaging outer bag, with a thin layer of soluble PVDF packaging bag inside.

　　For ternary NCA and NCM materials, a PVDF bag with a size of 350mmx460mm and a thickness of 80 microns is required. The weight is 43.52g and the volume is 8 liters. It can hold about 17 kilograms of NCA and NCM cathode materials. Such a bag will dissolve in NMP under stirring at room temperature for 5 minutes. Compared with the positive PVDF, the weight ratio of the bag is 43.52/17000=0.26%. The common PVDF addition in the ternary material positive electrode formula is 1.5% relative to the positive electrode, which means that the amount of PVDF bag relative to the entire PVDF adhesive is only 17.3%, which has no significant effect on the entire bonding effect, and it will not bring Impurities, because the PVDF bag is made of PVDF. Even if the amount of PVDF binder relative to the positive electrode is reduced to 1.0% in the formula, the amount of PVDF bag relative to the entire PVDF binder is only 26%.

　　What can bring immediate changes at present is the use of soluble PVDF packaging bag technology to process conductive agents-conductive carbon black (SP of TMICO), conductive graphite (KS-6 of TMICO), carbon nanotubes and PVDF The adhesive itself. With these materials, the impact of PVDF bags is completely negligible. For the feeding of conductive agent SP, the dust is very serious, and the technology of soluble packaging bag is urgently needed to improve the operating environment of feeding. This effect is immediate and there are no side effects. Conductive carbon black SP sold thousands of tons in China last year. This technology is also applicable to the negative electrode material, and the material of the packaging bag should be made of water-soluble polymer material.

　　The advantages of doing this are:

　　1, completely avoid dust pollution in the process of using lithium battery powder active materials;

　　2, can feed quickly;

　　3, easy to realize automation;

　　4. There is no need for complex ton bag feeding and air conveying technology, which saves the investment and cost of feeding equipment, and does not need to maintain the feeding equipment in the future;

　　5. There is no need for two times of weighing and metering, and the material can be accurately weighed;

　　6. Avoid sensitive battery materials (such as NCA) from contacting water and dust in the air, avoid air pollution in the feeding process, pollution caused by conveying machinery, and pollution caused by abrasion of conveying equipment;

　　7. Protect the health of workers and completely eliminate dust hazards;

　　8. The production of high-quality batteries requires a highly clean environment, and absolute dust-free pollution is a must for advanced battery companies.

　　In 2016, the domestic output of lithium battery cathode materials in China was 161,600 tons, an increase of 43% year-on-year, and the output value exceeded 20 billion yuan. In 2016, the domestic output of anode materials was 122,500 tons, a year-on-year increase of 68.27%. In 2016, the output value of anode materials was 6.639 billion yuan, a year-on-year increase of 64%. Based on a common 25 kg packaging bag, China’s cathode material industry needs 6.46 million such packaging bags each year; the anode material industry needs 4.9 million such packaging bags each year; and the adhesive and conductive agent industries also need the same. Dust-free pulping process for soluble packaging bags. It is feasible to provide such a solution to large-scale lithium battery factories through dissolvable packaging bags to achieve a clean pulping process. Additional technical fees are charged.

　　The entire battery industry related materials will grow several times in the future, and the scope of demand for such dust-free pulping process solutions will also increase several times. All lithium battery factories apply this kind of technology, and there is no exclusivity. Corresponding arrangements for intellectual property protection have been carried out, and there is no vicious competition. The author hopes that such a dust-free pulping process solution can contribute a small amount of power to the large-scale, automated, and humanized production of lithium batteries in China.