Dry Electrode Process

Dry Electrode Process – Dielectric Layer Coatings for Lithium-ion Battery Manufacturing – Cheersonic

Lithium-ion batteries dominate new energy power and energy storage equipment with their advantages such as high energy density, high power and long cycle life. With the development of commercial lithium-ion batteries, the industry’s requirements for their manufacturing cost and performance are becoming increasingly stringent. The cost and performance of lithium-ion batteries depend to a large extent on the manufacturing process of electrodes. Innovative, reliable and low-cost electrode manufacturing technology is crucial to promote the large-scale application of lithium batteries. At present, advanced commercial lithium batteries mainly use pulp coating to manufacture electrodes. This is a schematic diagram of the electrode manufacturing process of pulp coating process; pulping is the process of uniformly dispersing the anode or cathode active powder, conductive agent, binder and additive in the solvent to form a stable suspension. Generally speaking, deionized water is used for the anode, and the organic solvent N-methylpyrrolidone (NMP) is used for the preparation of cathode slurry. Coating is to cast the prepared slurry on the substrate through a slot die coater and then dry it in an oven tens of meters long. Drying is carried out at high temperature to evaporate the solvent in a short time. The drying temperature is affected by factors such as materials, solvents (water or NMP), and coating speed. The drying temperature is usually over 100°C, and the process is accompanied by a large amount of energy consumption. At the same time, in cathode manufacturing, due to the potential environmental hazards of NMP, an expensive and complex NMP recovery system is required, which further increases the manufacturing cost.

In the face of the demand for high energy density, the manufacture of thick electrodes is also a key development direction, and the pulp coating process severely limits the manufacture of thick electrodes. The thickness of commercial electrodes is usually less than 100 μm. The drying process of thick electrodes manufactured using the pulp coating process is prone to uneven distribution of binders. When the binder floats to the top of the electrode, it directly leads to low binder content in the electrode, poor cohesion between electrode particles, and the adhesion between the electrode and the current collector interface will also be affected; low cohesion and adhesion will further reduce the mechanical integrity of the electrode, resulting in reduced yield and declining production capacity. Compared with the pulp coating process, dry electrode manufacturing without solvent can potentially avoid all limitations of thick electrode manufacturing. In the dry electrode process, the binder, active material and conductive additive are dried and homogenized together, which can avoid the manufacture of thick electrodes under uneven binder distribution. The use of electrodes with increased thickness can significantly increase energy density. At the same time, the dry electrode process is one of the most promising solutions to reduce manufacturing costs and improve electrode quality, and it has attracted more and more attention. In general, the dry process has the following advantages:

  • Cost reduction. No solvent and its related evaporation, recovery and drying equipment are required. The dry electrode process can significantly reduce production costs. For example, the production of 1 million lithium-ion batteries can save about 56% of the cost.
  • Avoid electrode stratification. The dry electrode process can achieve uniform distribution of the components of the electrode material without using solvents, avoiding electrode stratification caused by solvent evaporation.
  • It can effectively increase the loading of electrode active substances. The dry electrode process is suitable for the preparation of thick electrodes, which can better control the thickness and uniformity of the electrode and is suitable for the preparation of ultra-high loading electrodes.
  • Environmentally friendly. Solvent-free dry electrode technology can effectively reduce pollution to the environment.

The dry electrode process is a new hope for green energy. It has advantages in cost and battery performance, and has potential application prospects in other processes such as solid-state batteries and pre-lithiation. At present, there are still huge challenges in process manufacturing and industrialization. The bonding mechanism of dry electrode binders, category differences, long-cycle performance at the cell level, and process stability evaluation are the focus of industry researchers. In the film-forming stage of the dry electrode process, Yuanneng introduced a series of equipment such as PRCD, BER, and EIC to evaluate the performance of powder and electrode layers, and to help modify the process ratio optimization agent process plan. In addition, for the post-process stage of the film-forming process, Yuanneng Technology also has relevant evaluation equipment for electrochemical performance analysis, cell gas production, expansion performance testing, etc. to evaluate and characterize the corresponding indicators, which can provide new support and ideas for scientific research and industrial applications.

Dry Electrode Process - Coatings for Lithium-ion Battery

Ultrasonic coating systems are used to apply polyimide coatings to create separator layers in applications where a chemically inert protective coating is required. Polyimide coatings are an alternative to tape for complex geometries and small areas such as channels and holes, encapsulating hazardous materials and protecting lithium and other hazardous substances from harmful reactions or leaks. Polyimides are widely used as flexible encapsulation materials in batteries using radioactive or highly reactive elements, and they have good structural integrity.

Ultrasonic spraying technology for polyimide separator coating has the following advantages:

  • Ultra-thin films with excellent porosity can be produced.
  • The resulting coating is durable, mechanically stable, and stable in each layer.
  • The nozzle has no moving parts that are prone to wear and has a long service life.
  • It has ideal dielectric properties to meet a variety of electrical needs.
  • Deep expertise in polyimide coatings and mature and reliable technology.
  • Extensive experience and superb craftsmanship in microporous membrane coatings.
  • The prepared film has extremely high uniformity, good repeatability and stable quality.
  • The obtained high-temperature resistant coating can function normally in a temperature environment up to 400 degrees Celsius and has a wide range of applications.

About Cheersonic

Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.

Our coating solutions are environmentally-friendly, efficient and highly reliable, and enable dramatic reductions in overspray, savings in raw material, water and energy usage and provide improved process repeatability, transfer efficiency, high uniformity and reduced emissions.

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