Main content:
The current collector is a key component in batteries, mainly used to collect and conduct the current generated by electrode active materials, ensuring efficient and stable operation of the battery. Beneficial for reducing the internal resistance of batteries, improving their coulombic efficiency, cycling stability, and rate performance.
In this article, lithium ion battery current collector will be discussed from the definition, working process and the importance inside lithium batteries.
What is a current collector in battery
Battery current collector is an important component of battery cells. Because the positive and negative electrode materials in batteries cannot quickly conduct current, a battery current collector is needed to collect and output the current generated by the active material during charging and discharging, or input the current to the active material, in order to achieve the conversion of chemical energy into electrical energy.
The commonly used current collector materials in lithium-ion batteries include metal conductor materials such as copper, aluminum, nickel, and stainless steel, as well as semiconductor materials such as carbon.
Specific types include:
Copper current collector: commonly used as a negative electrode current collector due to its high conductivity and abundant resources.
Aluminum current collector: commonly used as a positive electrode current collector due to its good chemical stability.
The ideal features of battery current collector
In principle, an ideal lithium-ion battery current collector should meet these conditions: High conductivity facilitates electronic transfer and improves the specific capacity and rate performance of lithium batteries.
- Good chemical and electrochemical stability, does not react with active substances, binders, and electrolytes.
- High mechanical strength, preventing damage to the battery caused by deformation under external forces such as collisions.
- Good compatibility and binding strength with electrode active materials, with strong adhesive strength.
- Cheap, easy to obtain, and lightweight.
However, in practical applications, different battery current collector materials still have various problems, so they cannot fully meet the various needs mentioned above.
The type of battery current collector
At present, materials that can be used as current collectors for lithium-ion batteries include metal conductor materials such as copper, aluminum, nickel, and stainless steel, semiconductor materials such as carbon, and composite materials.
Copper current collector
Copper is an excellent metal conductor with conductivity second only to silver, and has many advantages such as abundant resources, low cost and easy availability, and good ductility. However, considering that copper is prone to oxidation at higher potentials, it is suitable for use as a negative electrode current collector and is often used as a current collector for negative electrode active materials such as graphite, silicon, tin, and cobalt tin alloys. Common copper collectors include lithium battery copper foil, foam copper, copper mesh and three-dimensional nano copper array collector.
Aluminum current collector
Although the conductivity of aluminum metal is lower than that of copper, the quality of aluminum wire is only half that of copper wire when transporting the same amount of electricity. Undoubtedly, using aluminum current collectors can help improve the energy density of lithium-ion batteries.
In addition, compared to copper, aluminum is cheaper in price. During the charging/discharging process of lithium-ion batteries, a dense oxide film is formed on the surface of the battery aluminum foil current collector, which improves the corrosion resistance of the aluminum foil. However, corrosion problems are more severe when the negative electrode current collector is used, and it is often used as the positive electrode current collector in lithium-ion batteries.
Nickel current collector
Relatively speaking, nickel is a base metal with a relatively low price, good conductivity, and stability in acidic and alkaline solutions. Therefore, nickel can be used as both a positive electrode current collector and a negative electrode current collector. However, when nickel is used as a current collector, the active material is prone to detachment with increasing charge and discharge cycles, which affects battery performance.
There are both positive electrode active materials such as lithium iron phosphate and negative electrode active materials such as nickel oxide, sulfur, and carbon silicon composite materials that match it.
The shape of nickel collector usually includes foam nickel and nickel foil. Lithium iron phosphate is considered as an ideal positive active material for power lithium ion batteries because of its good safety and wide source of raw materials. Coating it on the surface of foam nickel collector can increase the contact area between LiFePO4 and foam nickel, reduce the current density of interface reaction, and thus improve the rate discharge performance of LiFePO4.
Stainless steel current collector
Stainless steel refers to alloy steel containing elements such as nickel, molybdenum, titanium, niobium, copper, and iron. It has good conductivity and stability, and can withstand chemical corrosion from weak corrosive media such as air, steam, and water, as well as strong corrosive media such as acid, alkali, and salt. Stainless steel surface is also prone to forming a passivation film, which can protect its surface from corrosion. At the same time, stainless steel can be processed thinner than copper, with advantages such as low cost, simple process, and large-scale production. Stainless steel can be used as a positive or negative current collector, and common types of stainless steel battery current collectors include stainless steel mesh and porous stainless steel.
Carbon collector fluid
When using carbon materials as positive or negative electrode current collectors, it can avoid the corrosion of electrolyte on metal current collectors, and it has the advantages of abundant resources, easy processing, low resistivity, no harm to the environment, and low price. Carbon fiber cloth can be used as a current collector for flexible lithium-ion batteries due to its excellent flexibility, conductivity, and electrochemical stability. Carbon nanotubes are another form of carbon current collector, which have obvious advantages over metal current collectors in terms of lightweight and can significantly improve the energy density of batteries.
Composite battery current collector
Composite current collector is a composite material formed by stacking double-layer copper/aluminum current seeking layers on both sides of the base film through processes such as vacuum coating, using polymer materials such as PET/PP as the intermediate layer base film, relative to two single current collectors. The advantages of different materials are maximized through the composite energy between them. In terms of structure, the composite battery current collector exhibits a "sandwich" structure of "metal PET/PP polymer material metal".
Tycorun batteries’ advantages in battery current collector
Material choose
Tycorun lithium batteries use high-purity copper foil and aluminum foil as current collector materials. With advanced processing technology, the battery current collector has extremely low resistance, making electronic flow smoother, ensuring fast current transmission, greatly improving charging and discharging efficiency, and maintaining stable and efficient output of the battery in power and energy storage applications.
High performance
Tycorun's battery current collector undergoes special anti-oxidation treatment, which can resist battery corrosion and avoid lithium deposition during long-term cycling, greatly extending the cycle life. Tycorun batteries can maintain excellent performance in complex environments such as high temperature and high humidity.
Advanced technology
By using precise coating technology, the battery current collector is tightly combined with the active material, reducing the phenomenon of active material detachment. High bonding strength, reduced internal resistance, reduced energy loss, and extended service life.
Conclusion
The current collector of lithium batteries is responsible for collecting and transmitting the current generated by the active materials, which plays a decisive role in the efficiency and lifespan of the battery.
The Tycorun battery current collector is selected from high-quality copper foil and aluminum foil, and advanced coating technology is used to ensure a tight bond between the current collector and the active material, reduce resistance and material detachment, ensure efficient conduction of the battery, and extend the battery cycle life.
With advanced technology, Tycorun batteries maintain excellent performance in complex environments such as high temperature and humidity, providing long-lasting and reliable power support for energy storage and power applications.
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