Nickel Metal Hydride No. 5 battery

　　What are the advantages of the new dust-free slurry process for Nickel Metal Hydride No. 5 battery?

　　In order to promote the electrochemical reaction and reduce the resistance of the electrode reaction, most lithium battery active materials use powder materials, including lithium battery positive electrode materials, negative electrode materials, adhesive materials, and conductive agent materials. The active materials of lithium batteries must be batched, mixed with corresponding solvents (such as NMP or water), stirred and dispersed (or dissolved) evenly, and made into a slurry before they can be used in the manufacture of lithium batteries.

　　During the slurry mixing process, small particles in the active material of the powder can easily cause dust pollution and dirty the working environment. A small amount of powdered active material remaining in the packaging bag after feeding is also easy to pollute the working environment. 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 clean slurry technology for lithium battery powder active materials, and made a corresponding intellectual property protection layout. During the slurry process of lithium battery powder active materials, corresponding dissolvable 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 dissolvable Packaging bag), put the dissolvable packaging bag and lithium battery powder active material into the solvent used in the pulping process, thereby achieving a clean pulping process and completely avoiding dust pollution.

　　Let's take a PVDF material packaging bag as an example. 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 in 5 minutes with stirring at room temperature. If used to hold lithium iron phosphate materials, it can hold about 6 kilograms, so the weight ratio of the bag to lithium iron phosphate is 21.76/6000=0.36%. The common addition amount of PVDF in the lithium iron phosphate cathode formula is 2.5% relative to the cathode, which means that the amount of PVDF bag relative to the entire PVDF adhesive is only 14.4%, which has no significant change or impact on the entire bonding effect and will not Bringing impurities, because PVDF packaging bags and adhesives are both made of PVDF. Even if the amount of PVDF binder in the formula is reduced to 1.5% relative to the lithium iron phosphate cathode, the amount of PVDF binder in the PVDF bag relative to the entire PVDF binder is only 24%. This soluble packaging bag actually just provides a simple film to prevent powder leakage. In actual production, the main packaging strength is provided by the aluminum-plastic film packaging outer bag, with a thin layer of soluble PVDF packaging bag inside.

　　To hold ternary NCA and NCM materials, a PVDF bag with a size of 350mmx460mm and a thickness of 80 microns needs to be used. 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 in 5 minutes with stirring at room temperature. Relative to the positive PVDF, the weight ratio of the bag is 43.52/17000=0.26%. The common PVDF addition amount in the ternary material cathode formula is 1.5% relative to the cathode, which means that the amount of PVDF bag relative to the entire PVDF adhesive is only 17.3%, which has no significant impact on the entire bonding effect and will not cause Impurities, because PVDF bags are made of PVDF. Even if the amount of PVDF adhesive in the formula is reduced to 1.0% relative to the positive electrode, the amount of PVDF adhesive in the PVDF bag relative to the entire PVDF adhesive is only 26%.

　　What can bring immediate change at present is the use of soluble PVDF packaging bag technology to treat conductive agents—conductive carbon black (SP from Temiko), conductive graphite (KS-6 from Temiko), carbon nanotubes and PVDF The adhesive itself. For 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 bags is urgently needed to improve the feeding operating environment. The effect is immediate and has no side effects. Thousands of tons of conductive carbon black SP were sold domestically last year. This technology is also applicable to negative electrode materials. The packaging bag can be made of water-soluble polymer material.

　　The benefits of doing this are:

　　1. Completely avoid dust pollution during the use of lithium battery powder active materials;

　　2. Feeding can be done quickly;

　　3. Easy to realize automation;

　　4. There is no need for complicated ton bag feeding and air conveying processes, saving investment and costs in feeding equipment, and no need for later maintenance of feeding equipment;

　　5. No secondary weighing is required, and materials can be accurately weighed;

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

　　7. Protect workers’ health and completely eliminate dust hazards;

　　8. Making high-quality batteries requires a highly clean environment, and absolute freedom from dust pollution is a must for advanced battery companies.

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