Skip to main content

Lithium-ion Full Cell Manufacturing Process Training-- electrolyte Section(II)

 1.High energy density system battery

1.1.Energy Density↗ ,Required Capacity↗, Voltage Platform↗,Weight↘,Volume↘

1.2.Set goals: (1) capacity, (2) energy density

1.3.Mass Energy Density = Capacity * Voltage Platform / Weight (Wh/kg)
Volumetric Energy Density = Capacity * Voltage Platform /Volume (Wh/L)

1.4.Material

1.4.1.Cathode Materials

1.4.1.1.In general, lithium cobalt oxide materials have high gram capacity, the highest voltage platform, the highest compaction density, and therefore the highest energy density.

1.4.1.2.At present, lithium cobalt oxide is widely used in consumer battery products, and mobile phone batteries are basically made of lithi um cobalt oxide as cathode materials.


 

 

Note: This table is an early reference book for lithium-ion batteries, and there have been many improvements and upgrades in recent years, such as:

 (1) At present, the maximum charging voltage of lithium cobalt oxide has been increased to 4.48~4.5V, the gram capacity has also been increased to ~185mAh/g, and the voltage platform has also been increased;

(2) In terms of price, the price of LFP has dropped to less than 100,000 yuan, and lithium manganese oxide has dropped to less than 50,000 yuan

1.4.2.Anode Materials

 

The silicon anode has the highest theoretical capacity, and the current commercially mature materials are mainly graphite and lithium titanate anode;

Graphite has different capacities such as 330, 340, 350, 360, etc., and the graphite capacity of 360mAh/g is the highest;

Graphite also has 1.5, 1.55, 1.65, 1.75g/cm3 and other different compacted graphite, the larger the compaction, the higher the energy density.

1.4.1. Separator

1.4.1 .1 PP separator is cheaper and has a higher melting point than PE separator, but due to the limitation of the manufacturing process, the thinnest thickness is currently 12um;

 

      1.4.1.2 The PE separator has a more uniform pore distribution, and the thickness

of the separator can be thin, and there is currently a 5um separator commercialized;

 

The thinner the separator thickness, the smaller the volume, and the higher the energy density of the battery.

1.4.3.Conductive Agents

 

The conductive agent has developed from the traditional conductive agent to a new type of conductive agent with nanoscale, high aspect ratio, high BET and high conductivity.

The reduction of the addition amount can effectively increase the proportion of active materials and improve the energy density of the battery.

CNT is currently widely used, with the characteristics of low addition amount and high conductivity, and is suitable for high energy density applications.

1.4.4.Adhesives

1.4.4.1.The role of the adhesive: the connection between the particles and the current collectors;Adhesives cannot effectively provide energy, so under the condition of ensuring basic adhesion, the less the amount of adhesive added, the higher the energy density of the battery.

 

1.4.4.2.The use of adhesives with large molecular weight and good adhesion can reduce the amount of use and improve the energy density of the battery under the condition of ensuring adhesion.

 

1.4.5.Aluminium plastic film, foil and tabs

1.4.5.1.Aluminum-plastic film: 88, 113, 152um, etc

 

1.4.5.2.Copper foil: 5, 6, 8, 9, 12um, etc

 

1.4.5.3.Aluminum foil: 9, 10, 12, 14, 16um, etc

 

1.4.5.4.Tabs: 0.08, 0.1, 0.2mm

 

1.5.Design

The higher the compaction density, the smaller the volume occupied;

The larger the coating weight, the smaller the proportion of auxiliary materials such as current collectors and separators, the smaller the number of layers, and the smaller the volume;

Increasing compaction and coating weight can both effectively improve the energy density of the battery.

 

The smaller the N/P ratio, the less excess anode material is required, resulting in reduced anode volume.

As the battery model increases in size, the proportion of volume occupied by auxiliary materials decreases.

Reducing the N/P ratio and increasing the cell size can effectively improve the energy density of the battery.

 

1.6.Coating

1.6.1.Transfer coating:The equipment is cheap and easy to operate .The thickness is not easy to control, and the coating speed is small

 

1.6.2.Extrusion coating:Controlled the coating thickness of the equipment, and the coating speed is fast (70m/min).The equipment is expensive and the cleaning is complicated

 

Adopted extrusion coating, with good thickness uniformity and high weight consistency;

The coating weight fluctuates less, which can further reduce the amount of negative electrode and improve the energy density of the battery.

1.7.Rolling and Formation

1.7.1.The rolling and forming process has a great impact on the thickness and capacity consistency of the battery, and control of related processes can effectively improve the capacity and thickness consistency of the battery, which is convenient for improving the energy density of the battery.

   
 

1.8.Energy density calculation method

 

Remarks: 455090-2.3Ah pouch battery, positive NCM523, negative artificial graphite

 
 
Remarks: 455090-2.3Ah pouch battery, positive NCM523, negative artificial graphite
 

1.9.High energy density batteries

The influencing factors vary according to volume and mass, energy density

Positive and negative electrode materials, compaction density and size have the greatest impact

 

2.Fast-charging battery

The fast charging of the battery is mainly reflected in the constant current charging stage, and the fast charging effect is better at about 2C, and continuing to increase the fast charging rate can not effectively reduce the charging time

 

The system development of fast-charging batteries mainly lies in materials and

design

The application of fast charging anode materials and the optimization of N/P ratio

have the most significant impact on the fast charging effect of batteries

 

2.Canrd Brief Introduce

Canrd use high battery R&D technology(core members are from CATL) and strong Chinese supply chain to help many foreign companies with fast R&D.    We provide lab materials, electrodes, custom dry cells, material evaluation, perfomance and test, coin/pouch/cylindrical cell equipment line, and other R&D services.

 

Email: contact@canrd.com    Phone/Wechat/WhatsApp: +86 19867737979

Canrd Official Web     Canrd Company Vedio     Canrd Company profile

Website : www.canrud.com

 

Comments

Popular posts from this blog

Lithium-ion Full Battery Manufacturing Process Training

Lithium-ion Full Battery Manufacturing Process Training 1. Basic Knowlege Of Mixing Slurry mixing is the process of adding active materials, conductive carbon black, dispersants, binders, additives, and other components to a mixing equipment in a certain proportion and order. Under the mechanical actions such as turning, kneading, and shearing generated by the equipment, these components are mixed together to form a uniform, stable solid-liquid suspension system suitable for coating.The goal is to achieve uniformity and consistency on both the macro and micro levels.

Lithium-ion Full Battery Manufacturing Process Training--Coating

  1. Coating Basics Purpose: To uniformly coat a fluid slurry onto the surface of a metal foil, dry it, and produce a battery electrode Principle: The coating roller rotates to carry the slurry, and the amount of slurry transferred is adjusted by adjusting the gap between the doctor blade and the roller. The relative rotation of the back roller and the coating roller is used to transfer the slurry onto the substrate. Subsequently, the solvent in the slurry is evaporated through drying and heating, causing the solid matter to adhere to the substrate.

Lithium-ion Full Cell Manufacturing Process Training--Soft-Pack Battery Formation - Part 2

1.  Key Factors Influencing Formation: Mechanism Generation Process of SEI Membrane: l  Electrons are transferred from the current collector, through the conductive agent, to point A inside the graphite particles where the SEI membrane is to be formed. l  Solvated lithium ions, wrapped in the solvent, diffuse from the cathode to point B on the surface of the SEI membrane that is currently being formed. l  The electrons at point A diffuse to point B through the electron tunneling effect. l  The electrons that jump to point B react with lithium salt, solvated lithium ions, film-forming agents, etc., to continue generating the SEI membrane on the surface of the existing SEI membrane. This process results in the continuous increase of the SEI membrane thickness on the surface of the graphite particles, ultimately leading to the formation of a complete SEI membrane.