News

  The current collector is one of the indispensable components of lithium-ion batteries, which can not only carry the active material, but also converge and output the current generated by the electrode active material, which is conducive to lowering the internal resistance of lithium-ion batteries, and improving the battery's Coulombic efficiency, cycling stability, and multiplier performance.   Lithium-ion battery current collector   In principle, the ideal lithium-ion battery fluid collector should meet the following conditions: (1) high conductivity; (2) good chemical and electrochemical stability; (3) high mechanical strength; (4) good compatibility and bonding with the electrode active substance; (5) cheap and easy to obtain; (6) light weight.   Currently, the materials that can be used as lithium-ion battery collectors include metal conductor materials such as copper, aluminum, nickel and stainless steel, semiconductor materials such as carbon, and composite materials.   2.1 Copper collector Copper is an excellent metal conductor with electrical conductivity second only to silver, and has many advantages such as abundant resources, cheap and easy to obtain, and good ductility. However, considering that copper is easy to be oxidized at higher potentials, it is often used as a collector for negatively active substances such as graphite, silicon, tin and cobalt-tin alloys. Common copper collectors include copper foils, copper foam and copper mesh, and three-dimensional copper nano-array collectors.   2.2 Aluminum Collector Although the conductivity of the metal aluminum is lower than that of copper, the mass of the aluminum wire is only half that of the copper wire when delivering the same amount of power, and there is no doubt that the use of an aluminum collector contributes to an increase in the energy density of lithium-ion batteries. In addition, compared with copper, aluminum is more affordable. During the charging/discharging process of lithium-ion batteries, a dense oxide film is formed on the surface of the aluminum foil collector, which improves the corrosion resistance of the aluminum foil, and it is often used as the collector for the positive electrode in lithium-ion batteries.   2.3 Nickel collector Comparatively speaking, nickel is a base metal, relatively inexpensive, has good electrical conductivity, and is more stable in acid and alkaline solutions, so nickel can be used as both positive and negative electrode collectors. It is matched with both positive active substances such as lithium iron phosphate and negative active substances such as nickel oxide, sulfur and carbon and silicon composites. The shape of nickel collector is usually of two types: nickel foam and nickel foil.   2.4 Stainless steel collector Stainless steel is an alloy steel containing elements such as nickel, molybdenum, titanium, niobium, copper, iron, etc. It has good electrical conductivity and stability, and it c...

To Our Valued Business Associates, Clients and Friends, Mid-Autumn Festival and National Day holiday is coming, Please accept our best wishes: May the Mid-Autumn Festival bring you and your family abundant blessings and prosperity, filled with happy moments and cherished memories. We will have Mid-Autumn Festival and National Day holiday from September 29th to October 6th 2023. Emergency Contact: Tel : +86-18120715609 Email : tob.amy@tobmachine.com

TOB-DZF-6050 Vacuum Oven TOB-XFZH02 Planetary Vacuum Mixer TOB-XJB-500 Planetary Vacuum Mixer 500ml TOB-SY-300J Transfer Coating Machine TOB-CP-500 Big Electrode Butter TOB-HRP300 Hydraulic Rolling Press TOB-MQ300 Semi Auto Electrode Die Cutter TOB-BDP200-C Semi Auto Stacking Machine TOB-USW-800W Ultrasonic Welding System with Stage TOB-SCK-300 Auto Aluminum Poach Forming TOB-SFZ-200 Top Side Sealing TOB-YF200-JZ Electrode Diffusion Chamber TOB-BFZ-200 Secondary Sealing Machine  Email :tob.amy@tobmachine.com  Skype :amywangbest86  Whatsapp/Phone number :+86 181 2071 5609

TOB-NDJ-5S Viscometer For Battery Slurry TOB-LB-FT02 De-Ironing Filtration System 53*41cm Cutter Die TOB-DR-H150-200 Roller Press Machine TOB-MQ300 Battery Electrode Cutter TOB-M-DP200 Battery Stacking Machine TOB-SCK200  Pouch Cell Forming Machine TOB-USW-2600W Spot Welding Machine TOB-SFZ-200  Battery Heat Sealing Machine TOB-ADT- 001 Aluminum Laminated Film Short Circuit Tester  TOB-YF200- JZ Vacuum Diffusion Chamber With Pre-Sealing All-In-One Machine TOB-BFZ-200 Battery Secondary Vacuum Heat Sealing Machine  Email :tob.amy@tobmachine.com  Skype :amywangbest86  Whatsapp/Phone number :+86 181 2071 5609

Battery charging and discharging once is called a cycle, cycle life is an important indicator of the battery life performance. Factors affecting the cycle life of lithium-ion batteries inherent in the root cause, is to participate in the energy transfer of lithium ions in the number of decreasing. The total amount of lithium in the battery does not decrease, but the "activated" lithium ions are less, they are confined in certain places or the transmission channel is blocked, and can not freely participate in the charging and discharging process. Specifically: (1) Precipitation of lithium metal (2) Decomposition of cathode material (3) SEI film on the electrode surface: carbon anode material, during the initial cycle, the electrolyte will form a solid electrolyte (SEI) film on the electrode surface, and the formation process of SEI film will consume lithium ions. (4) Loss of electrolyte (5) Diaphragm blockage or damage (6) Dislodging of cathode and anode electrode materials  Email : tob.amy@tobmachine.com  Skype : amywangbest86  Whatsapp/Phone number : +86 181 2071 5609

Common Problems and Solutions for Binder  (PVDF, SBR, CMC, PAA, etc.) What about slurry settlement? Reason: l  The selected CMC type is not applicable, and the degree of substitution and molecular weight of CMC will affect the stability of the slurry to a certain extent, such as poor hydrophilicity of CMC with low substitution, good wettability to graphite, but poor suspension capacity of slurry; l  The amount of CMC is small, and the slurry cannot be effectively suspended; l  Too much CMC is involved in the kneading process, resulting in insufficient CMC free between particles and in suspension, which often leads to poor slurry stability; l  High mechanical forces and fluctuations in the acidity or alkalinity of the slurry can lead to breakage of the SBR, which can cause the slurry to settle; Solutions: l  Change or match CMC with high substitution degree and high molecular weight, for example, match WSC with CMC2200 in mass production formula, WSC itself has low molecular weight and low substitution degree, good wetting of graphite and weak suspending ability, after matching with CMC2200, the stability of the slurry has been greatly improved; l  Increasing the amount of CMC is one of the most effective means of improving paste stability, but it is important to find a balance between process capability and the low temperature performance of the cell; l  Reducing the amount of CMC used in kneading and increasing the amount of free CMC can improve the stability of the paste to a certain extent; l  After SBR is added to the slurry system, the stirring speed of the rotation should be reduced; What should I do if the hole is blocked during filtration and cannot be filtered? Reason: l  poor wetting of the active substance, no dispersion; l  Failure to filter due to SBR emulsion breakage; Solution: l  Using kneading process; l  After SBR is added to the slurry system, the stirring speed of the rotation should be reduced to prevent the occurrence of demulsification; What should I do if there is gel in the slurry? Reason: Gel production is mainly divided into two types, one is a physical gel and the other is a chemical gel. l  Physical gel: Cathode active materials, SP, solvent NMP have absorbed water, or the water content in the environment exceeds the standard, which is easy to form physical gels.This is because the polymer chain of PVDF is wrapped around the particles, and when the content of the slurry exceeds the standard, the polymer chain movement is blocked, and the polymer chains are entangled with each other, which reduces the fluidity of the slurry and the gel phenomenon occurs. l  Chemical gels: Chemical gels are prone to occur in the process of preparing high nickel or highly basic active materials or in stationary processes.This is because PVDF in the high pH environment of the base (as shown in the figure below), the polymer backbone is easy to de-HF to form double ...

TOB-ZKJB-500 Vacuum Mixing Machine TOB-GL-500 Slurry Filtration TOB-NDJ-5S Viscometer for Slurry TOB-JS100L Roll to Roll Coating Machine TOB-DZF-6050 Vacuum Oven TOB-DHG-9053A Oven TOB-X1200-30S Furnace TOB-MQ100-H Electrode Die Cutter For Pouch Cell TOB-M-DP-200 Battery Stacking Machine For Pouch Cell TOB-YF200-JZ Pouch Battery Electrolyte Vacuum Diffusion Chamber With Pre-Sealing All-In-One Machine TOB-BFZ200 Battery Secondary Vacuum Heat Sealing Machine TOB-SCK-200 Lab Polymer Battery Pouch Forming Machine TOB-SFZ-200 Battery Heat Sealing Machine For Top-Side Sealing TOB-XT-180 Laboratory Glass Coating Plate TOB-S100 Battery Electrode Sample Collector Email : tob.amy@tobmachine.com Skype :amywangbest86 Whatsapp/Phone number :+86 181 2071 5609

In lithium-ion batteries, the binder is one of the important factors affecting the stability of the electrode structure. According to the nature of the dispersing medium, lithium-ion battery binder can be divided into oil-based binder with organic solvent as dispersant and water-based binder with water as dispersant. Liu Xin et al [3] reviewed the research progress of binder for high-capacity negative electrode. Thinking about the application of polyvinylidene fluoride (PVDF)-modified binders and water-based binders, Can improve the performance of high-capacity negative electrode electrochemistry. However, there is no discussion or comparison for binders for silicon-based negative electrodes. In this paper, the authors provide an overview of the research progress on binders for silicon-based anode materials and compare the advantages and disadvantages of different types of binders. 1.     Oil-based binder Among the oil-based binders, homopolymers and copolymers of PVDF are the most widely used. 1.1  PVDF Homopolymer Binder In the large-scale production of lithium-ion batteries, PVDF is commonly used as a binder, and organic solvents such as N-methyl pyrrolidone (NMP) are used as dispersants. PVDF has good viscosity and electrochemical stability, but poor electronic and ionic conductivity, Organic solvents are volatile, flammable, explosive and highly toxic; Moreover, PVDF is only bonded to the Si-based anode material by weak van der Waals forces and cannot accommodate the dramatic volume change of Si. Conventional type PVDF is not suitable for silicon-based anode materials [3 -5]. 1.2  PVDF modified binder In order to get the improved electrochemical performance of PVDF applied to silicon-based anode materials, Some scholars have proposed modification methods such as copolymerisation and heat treatment [4-5]. Z. H. Chen and other scholars [4] found that: The terpolymer polyvinylidene fluoride-tetrafluoroethylene-ethylene copolymer [P(VDF- TFE-P)] enhances the mechanical properties and viscoelasticity of PVDF. J. Li and other scholars [5] found that. Heat treatment at 300°C and under argon protection improves the dispersion and viscoelasticity of PVDF. The modified PVDF/Si electrode was cycled 50 times at 150 mA/g at 0.17 ~ 0_ 90 V with a specific capacity of 600 mAh/g. By modifying and treating the PVDF/Si electrode, the cycling performance was improved, but the cycling stability was still unsatisfactory. 2.     Water-based binder Compared to oil-based binders, water-based binders are environmentally friendly, inexpensive and safer to use, and are gradually gaining popularity. Currently, the more researched silicon-based anode material binders are water-based binders such as sodium carboxymethyl cellulose (CMC) and polyacrylic acid (PAA). 2.1 Styrene-Butadiene Rubber (SBR)/Sodium Carboxymethyl Cellulose Abatement (CMC) Binder SBR/CMC has good viscoelasticity and dispersibility, and has been widely...