Keyword search: battery plant , lithium battery factory , power bank works , lifepo4 battery mill , lithium forklift battery manufacturer

The production process of lithium batteries can be divided into three stages: the manufacturing of the front electrode, the packaging of the middle electrode, and the activation of the rear battery. The purpose of the battery activation stage is to fully activate the active substances and electrolyte in the battery to achieve stable electrochemical performance. The activation stage includes stages such as pre charging, formation, aging, and constant volume. The purpose of pre charging and formation is to activate the positive and negative electrode materials through the initial few charges and discharges, so that the materials are in the optimal state of use.

The main purposes of aging are: firstly, to make the electrolyte more well wetted, which is conducive to the stability of battery performance; Secondly, after aging, the active substances in the positive and negative electrode materials can accelerate some side effects, such as gas production and electrolyte decomposition, allowing the electrochemical performance of lithium batteries to quickly reach stability; The third is to conduct consistency screening of lithium batteries after aging for a period of time. After formation, the voltage of the battery cell is unstable, and its measured value may deviate from the actual value. After aging, the voltage and internal resistance of the battery cell are more stable, making it easier to screen batteries with high consistency.

The aging system has two main factors that affect the performance of lithium batteries, namely aging temperature and aging time. In addition, it is also important whether the battery is in a sealed or open state during aging.

For the opening process, if the factory can control the humidity well, it can be sealed after aging. If high-temperature aging is used, aging after sealing is better. For different battery systems, such as ternary positive electrode/graphite negative electrode lithium batteries, lithium iron phosphate positive electrode/graphite negative electrode lithium batteries, or lithium titanate negative electrode batteries, targeted tests need to be conducted based on material and lithium battery characteristics. In experimental design, the optimal aging schedule can be determined by the capacity difference, internal resistance difference, and voltage drop characteristics of lithium batteries.

1、 Ternary or lithium iron phosphate positive electrode/graphite negative electrode lithium battery

For lithium-ion batteries with ternary as the positive electrode material and graphite as the negative electrode material, a solid electrolyte film (SEI) is formed on the surface of the graphite negative electrode during the pre charging stage of lithium-ion batteries. The formation potential of this film is about 0.8V, and SEI allows ions to penetrate but not electrons to pass through. Therefore, after forming a certain thickness, it will inhibit further decomposition of the electrolyte, It can prevent battery performance degradation caused by electrolyte decomposition. However, the SEI membrane formed after formation has a compact structure and small pores. Further aging of the battery will help to restructure the SEI structure and form a loose and porous membrane, thereby improving the performance of lithium batteries.

The aging of ternary/graphite lithium batteries usually takes 7-28 days at room temperature, but some factories also adopt a high-temperature aging system, with an aging time of 1-3 days. The so-called high temperature is generally between 38 ℃ and 50 ℃. High temperature aging is just to shorten the entire production cycle, and its purpose is the same as room temperature aging, which is to fully balance the positive and negative electrodes, separators, electrolytes, and other chemical reactions to achieve a more stable state of lithium batteries.

2、 Lithium titanate negative electrode lithium battery

The commonly known lithium titanate battery is a battery with a negative electrode made of lithium titanate, while the positive electrode material is mainly composed of ternary, lithium cobalt, and other materials. The difference between lithium titanate batteries and graphite negative electrode batteries is that the lithium intercalation potential of lithium titanate is 1.55V (relative to lithium metal), which is higher than the 0.8V formed by SEI. Therefore, during the charging and discharging process, no solid electrolyte film (SEI) or dendritic lithium will be formed, which has higher safety.

This means that during the charging process of lithium titanate, there are continuous reactions between electrons and the electrolyte, generating by-products and gases such as hydrogen, CO, CH4, C2H4, which can cause the battery to bulge. The bulging problem of lithium titanate mainly relies on changes in material properties to alleviate, such as surface coating, changing particle size distribution, and finding a suitable electrolyte.

In addition, optimizing the system of pre charging, formation, and aging can also appropriately reduce the phenomenon of lithium titanate bulging. The aging system of lithium titanate batteries is generally the preferred high-temperature aging system, with an aging temperature of 40 ℃ -55 ℃ and an aging time of 1-3 days. After aging, negative pressure exhaust is required. Performing multiple high-temperature aging tests to fully react with the internal moisture of the battery can effectively suppress the bloating problem of lithium titanate batteries and improve their cycling life.

Regardless of the battery system, aging is an essential process. Although the aging of lithium batteries can be understood as a loss and damage to them, it is actually an effective way to screen batteries with high consistency and eliminate defective products. Only through aging can lithium batteries suitable for packaging be selected to improve the service life of electric tools.

Lithium ForkLift Batteries ,Ensure Quality

Our lithium battery production line has a complete and scientific quality management system

Ensure the product quality of lithium batteries

Years of experience in producing lithium forklift batteries

Focus on the production of lithium batteries

WE PROMISE TO MAKE EVERY LITHIUM BATTERY WELL

We have a comprehensive explanation of lithium batteries

QUALIFICATION CERTIFICATE

THE QUALITY OF COMPLIANCE PROVIDES GUARANTEE FOR CUSTOMERS

MULTIPLE QUALIFICATION CERTIFICATES TO ENSURE STABLE PRODUCT QUALITY

Providing customers with professional and assured products is the guarantee of our continuous progress.

Applicable brands of our products