Lithium battery manufacturing process. Lithium - Ion Battery Equipment

In today's energy field, lithium batteries occupy an important position with their excellent performance. From the 21700 lithium-ion batteries used in Tesla electric vehicles that we are familiar with to the power sources in various electronic devices, lithium batteries are everywhere. So, how are these high-performance lithium batteries actually manufactured? Let's explore the mysterious journey of lithium battery manufacturing together.（Lithium - Ion Battery Equipment）

Lithium batteries are mainly divided into two categories: lithium metal batteries and lithium-ion batteries. Among them, lithium-ion batteries are rechargeable and do not contain metallic lithium. Below, we will use pictures and texts to explain in detail the 21 production processes of lithium batteries.

1. Negative electrode slurry mixing
   Negative electrode slurry mixing is one of the key links in lithium battery manufacturing. In this process, negative electrode active materials, conductive agents, binders and other components are mixed together to form a uniform paste through kneading. The mixed slurry needs to be processed. For example, methods such as ultrasonic degassing and vacuum degassing are used to remove bubbles and impurities and improve the fullness, stability and processability of the slurry.

Advantages and highlights: Through accurate mixing ratio and kneading process, ensure the uniformity of negative electrode materials and lay the foundation for subsequent battery performance. Ultrasonic degassing and vacuum degassing can efficiently remove tiny bubbles in the slurry, making the negative electrode paste more compact and improving the charge and discharge efficiency and cycle life of the battery.

 

2. Positive electrode slurry mixing
   Positive electrode slurry mixing is also extremely important. It mixes positive electrode active materials, conductive agents, binders and other additives into a uniform slurry, laying the foundation for subsequent processes such as coating and pressing. The advantage of the positive electrode slurry mixing process is that it can ensure that the positive electrode material is fully mixed with each component and improve battery performance and stability. By precisely controlling the slurry ratio and process parameters, positive electrode materials with stable performance and reliable quality can be prepared.

Advantages and highlights: The carefully selected combination of positive electrode active materials and additives makes the positive electrode slurry have high energy density and good electrochemical performance. The strictly controlled slurry mixing process ensures the uniform distribution of materials, reduces local performance differences, and improves the overall consistency and reliability of the battery.

 

3. Coating
   Coating technology is a process of coating adhesives and other fluids on the substrate and forming a special functional film layer after drying or curing in an oven. It is widely used in many industries such as industry, people's livelihood, electronics and optoelectronics. Its advantages include high efficiency, which can realize high-speed and continuous coating operations; uniformity, ensuring uniform coating thickness through a precise control system; flexibility, suitable for a variety of substrates and coating materials; environmental protection, using low-pollution and low-energy-consumption equipment and processes.

Advantages and highlights: Advanced coating equipment can quickly and accurately coat the slurry on the substrate, greatly improving production efficiency. The high-precision control system ensures that the coating thickness error is within a very small range, ensuring the stability of battery performance. According to different battery types and requirements, suitable substrates and coating materials can be selected to meet diverse market needs. At the same time, the environmentally friendly coating process reduces the impact on the environment.

 

4. Rolling
   The roller press decomposes anode and cathode materials into smaller particles or firmly fixes multiple thin sheets together to form a tight positive and negative electrode structure. It is composed of a main shaft, grinding wheels, a feeding device, a transmission system and a control system. When working, the lithium battery material is sent into the feed port, the main shaft drives the grinding wheel to rotate, and the material is sandwiched between two grinding wheels and compressed into the required shape and size. Its technical characteristics are reflected in high efficiency, uniformity, flexibility and environmental protection.

Advantages and highlights: The efficient rolling process can quickly process a large amount of materials and improve production efficiency. The uniform pressure distribution makes the positive and negative electrode materials closer, increasing the energy density and cycle life of the battery. Flexibility enables the equipment to adapt to materials of different thicknesses and specifications to meet the requirements of different battery designs. In terms of environmental protection, a low-noise and low-energy-consumption design is adopted to reduce the burden on the environment.

 

5. Slitting
   Slitting plays an important role in battery manufacturing. It longitudinally slits the coated wide film into multiple pieces and winds them into upper and lower single rolls of a certain width specification to prepare for subsequent battery assembly.

Advantages and highlights: High-precision slitting equipment can ensure that the width of the pole pieces is uniform, reducing errors in the assembly process. The fast slitting speed improves production efficiency and meets the needs of large-scale production. The slitted pole pieces have neat edges, which is beneficial to improve the safety and performance stability of the battery.

 

6. Pole piece baking
   Pole piece baking aims to remove moisture and volatile organic compounds in the pole piece to improve the stability and reliability of the pole piece. The baking process includes the preparation stage, which involves checking and preheating the equipment and pretreating the pole piece; the baking stage, which is carried out according to the set time and temperature; and the cooling stage, which protects the pole piece from thermal damage and stabilizes its performance.

Advantages and highlights: Strictly controlled baking temperature and time can effectively remove moisture and impurities in the pole piece, improve the purity and conductivity of the pole piece. The fine treatment in the preheating and cooling stages ensures the stability of the pole piece during the baking process and reduces deformation and damage caused by temperature changes. The baked pole piece has better performance and prolongs the service life of the battery.

 

7. Winding
   Winding tightly winds the positive electrode, negative electrode, separator and other components together to form a battery cell. Precise winding control can ensure uniform distribution of materials inside the battery and improve efficiency and safety. Key parameters such as winding speed, tension and alignment have important influences on battery performance and quality.

Advantages and highlights: Advanced winding equipment can achieve high-precision winding control, ensure the tight fit between the positive and negative electrodes and the separator, reduce internal voids, and improve the energy density of the battery. Reasonably adjusting the winding speed and tension can not only ensure production efficiency but also avoid excessive stretching or loosening of materials and improve the performance stability of the battery. Good alignment makes the current distribution inside the battery more uniform and reduces the risk of local overheating and damage.

 

8. Casing insertion
   The casing insertion process is a key link in battery production. Putting the battery cell into the battery case can protect the battery cell and ensure safety and performance stability. The process includes battery cell assembly, battery case assembly, sealant application, battery cell placement, battery case closure and welding fixation.

Advantages and highlights: The carefully designed battery case can effectively protect the battery cell from the influence of the external environment and improve the safety of the battery. The application of sealant ensures the tightness of the battery and prevents moisture and impurities from entering, prolonging the service life of the battery. The precise assembly process and welding fixation ensure the firmness of the battery structure and improve the impact resistance and vibration resistance of the battery.

 

9. Spot welding
   The battery spot welding process welds the electrode material on the battery component to the conductive strip. Using the principle of resistance heating, instant high-temperature heating melts the welding material to form a solder joint connection. The process flow includes preparation work, setting welding parameters, installing battery components, performing welding, inspecting welding quality and performing rework or grinding. The spot welding process is continuously optimized and developed. For example, introducing robot welding technology to improve efficiency and optimizing parameters to improve quality and stability.

Advantages and highlights: The spot welding process can achieve fast and reliable connections and ensure good conductivity between the electrode and the conductive strip. Accurately set welding parameters can control the welding temperature and time to avoid excessive damage to battery materials. The application of robot welding technology improves the precision and efficiency of welding and reduces human errors. Strict welding quality inspection ensures the quality of each solder joint and improves the overall performance and reliability of the battery.

 

10. Baking
    The battery baking process removes moisture inside and outside the battery to improve stability and reliability. It also helps with welding circulation and simulates the battery aging process. The specific process includes temperature setting, heating and preheating, stable baking, cooling and shutdown, and inspection and verification.

Advantages and highlights: Reasonable temperature setting and baking time can thoroughly remove moisture in the battery, reduce the humidity inside the battery, and improve the insulation performance and stability of the battery. The baking process helps the welding points fully solidify and improves the welding quality. Simulating the battery aging process can detect potential problems in advance and ensure the reliability of the battery during use. The cooling and inspection verification steps ensure that the performance of the battery after baking meets the requirements.

 

11. Liquid injection
    In battery manufacturing, liquid injection controls the amount and injection time of liquid electrolyte and injects the electrolyte into the battery from the injection port. The purpose is to form an ion channel to ensure the reversible circulation of lithium ions between the positive and negative electrode sheets. The process flow includes pretreatment, liquid injection, placement and detection.

Advantages and highlights: Precise control of the injection amount and speed can ensure the uniform distribution of the electrolyte inside the battery and form a good ion channel. The pretreatment process removes impurities and residual electrolyte inside the battery and improves the quality of liquid injection. Reasonable control of the placement time allows the electrolyte to fully penetrate into the battery interior and improve the performance of the battery. Strict detection ensures that the liquid injection quality meets the requirements and guarantees the reliability of the battery.

 

12. Welding the cap
    The welding cap process fixes the battery cap on the battery to protect the interior of the battery from damage and ensure the safe isolation of the positive and negative electrodes. With the development of technology, welding equipment and technology are continuously optimized to reduce costs and improve performance.

Advantages and highlights: High-quality battery caps can effectively protect the internal structure of the battery and prevent external factors from causing damage to the battery. Advanced welding equipment and technology ensure a firm connection between the cap and the battery and improve the sealing and safety of the battery. The optimized process reduces production costs while improving the performance and reliability of the battery.

 

13. Cleaning
    Battery manufacturing cleaning removes dirt, impurities and residues on the battery surface to improve battery performance and lifespan. Cleaning methods include immersion method, spraying method and ultrasonic cleaning method.

Advantages and highlights: The immersion method can fully soak battery components and remove stubborn dirt on the surface. The spraying method can quickly wash off surface impurities and improve cleaning efficiency. The ultrasonic cleaning method uses the vibration of ultrasonic waves to penetrate into the fine pores of battery components and thoroughly remove dirt and residues. The combination of multiple cleaning methods ensures the cleanliness of the battery and improves the performance and reliability of the battery.

 

14. Dry storage
    Dry storage ensures a dry and moisture-free internal environment of the battery. Moisture will affect battery performance and lifespan and even cause safety accidents. Environmental requirements include temperature control at 20 - 30°C, humidity control at 30 - 50%, and the particle concentration of air quality should not be higher than 100,000 particles/cubic meter and be filtered. Two methods of vacuum drying and oven drying are adopted.

Advantages and highlights: Strictly controlled temperature and humidity conditions can effectively prevent the battery from getting damp and keep the battery's performance stable. A low particle concentration environment reduces pollution to the battery and improves the quality of the battery. The two methods of vacuum drying and oven drying can be selected according to different battery types and requirements to ensure the drying effect and improve production efficiency.

 

15. Detecting alignment
    Battery alignment refers to the accuracy of the relative positions and angles of internal components, which is related to the physical structure, electrochemical performance and safety of the battery. The detection process includes preparation stage, positioning the battery to be tested, taking images, image processing, edge detection, calculating alignment, determining alignment and recording results. Different types of batteries and application scenarios have different alignment requirements. For example, the double-sided alignment of lithium batteries is usually within 0.02mm.

Advantages and highlights: High-precision detection equipment and methods can accurately measure the alignment of battery internal components and ensure the stability of the battery's physical structure. Good alignment can improve the electrochemical performance of the battery and reduce the risk of internal short circuits. Strict alignment standards ensure the quality and safety of the battery and meet the needs of different application scenarios.

 

16. Case coding
    Case coding marks variable information such as product batch number, barcode and QR code on the battery case to ensure product traceability and identifiability. Coding requirements include accurate content, precise location, clear quality, suitable ink adhesion and drying time.

Advantages and highlights: Clear and accurate coding content facilitates product traceability and management and improves the controllability of the production process. The precise coding position ensures the aesthetics and readability of the coding information. High-quality coding effects ensure the recognition rate of barcodes and QR codes, facilitating the circulation and sales of products. Appropriate ink adhesion and drying time ensure the durability of the coding and are not easy to wear and fall off.

 

17. Formation
    Formation, also known as activation, is an important process in battery manufacturing. Through charging and discharging methods, the electrochemically active substances inside the battery are activated to form a stable solid electrolyte interface film (SEI film) to ensure high-performance and safe operation of the battery. It includes steps such as forming the SEI film during the first charge, charging with stepped current to improve efficiency, and discharging and recharging to test performance.

Advantages and highlights: The first charge in the formation process can effectively activate the active substances inside the battery and form a stable SEI film, improving the storage performance, cycle life, rate performance and safety of the battery. The stepped current charging method not only improves production efficiency but also ensures the uniformity and stability of the SEI film. The process of discharging and recharging can further test the performance of the battery and ensure that the quality of the battery meets the requirements.

 

18. OCV measurement
    OCV is the potential difference between the positive and negative electrodes of the battery in an open circuit state, reflecting the internal electrochemical state of the battery and being closely related to the state of charge, capacity and health status. The measurement principle is to disconnect the external load and wait for the internal chemical reaction of the battery to reach equilibrium and then measure the open circuit voltage. Methods include static test method, rapid test method and charge-discharge cycle test method.

Advantages and highlights: Accurate OCV measurement can provide an important basis for battery performance evaluation, life prediction and fault detection. The static test method is simple and easy to implement and can accurately reflect the real state of the battery. The rapid test method can shorten the test time and improve production efficiency. The charge-discharge cycle test method can more comprehensively evaluate the performance and stability of the battery and provide strong support for battery quality control.

 

19. Normal temperature storage
    Normal temperature storage is a link to ensure the stability of battery performance and quality. For short-term storage, the temperature is controlled at -20°C to 35°C and the humidity is 65±20% RH; for long-term storage, the temperature is 10°C to 25°C, the humidity is the same, and 50% - 70% of electricity needs to be charged and regular charge and discharge is required. The storage environment should be dry, free of corrosive gases, well ventilated, and away from water sources, fire sources and high temperatures.

Advantages and highlights: Reasonable temperature and humidity control can keep the battery's performance stable and prolong the service life of the battery. Charging an appropriate amount of electricity and regular charge and discharge can prevent irreversible capacity loss caused by excessive self-discharge of the battery. A good storage environment can avoid the battery being affected by external factors and ensure the safety and reliability of the battery.

 

20. Capacity grading
    Battery capacity grading is to sort and screen batteries by capacity and performance. Through charging and discharging to record data, data such as the capacity and internal resistance of each battery are obtained to determine the quality grade. The purposes include quality screening, capacity matching, voltage balancing, ensuring safety and improving efficiency.

Advantages and highlights: The capacity grading process can accurately screen out batteries with inconsistent quality and ensure that every battery that reaches consumers is a high-quality product that has been strictly tested. Capacity matching can improve the effect of multi-battery combination use and improve overall performance. Voltage balancing can guarantee the performance and lifespan of lithium battery packs. Through capacity grading, abnormalities in the production process can be found to avoid potential safety hazards and improve the charge and discharge efficiency of the battery.

 

21. Final process
    Appearance inspection, coding, scanning second inspection, packaging, and warehousing of finished products. The manufacturing process of lithium batteries is complex and meticulous. Every process is related to the performance and quality of the battery. From the mixing of raw materials to the final product inspection, every link embodies the power of technology and the spirit of craftsmen.

As a leader in the industry, Yixinfeng has always been committed to providing advanced equipment and solutions for lithium battery manufacturing. Our new equipment has demonstrated excellent performance and advantages in all aspects of lithium battery manufacturing. Whether it is high-efficiency and precise coating equipment, stable and reliable winding equipment, or intelligent detection equipment, it can bring higher efficiency, better quality and stronger competitiveness to your lithium battery production. Choosing Yixinfeng is choosing quality and innovation. Let's join hands to create a better future for lithium battery manufacturing.

Laser flexible die-cutting machine (special for blades and stacked batteries)
The laser flexible die-cutting machine is a device that uses laser technology for die-cutting processing. It generates high thermal energy through the focusing of the laser beam to cut materials. It has high quality, high precision, high efficiency, is easy to use, and has high safety. It can be changed with one key and has low cost.

Laser pole piece surface treatment equipment
Laser scribing technology can improve battery cycle retention rate and reduce battery internal resistance, increase energy per unit area of the battery, and improve energy density and rate.

Laser die-cutting winding and flattening integrated machine (large cylinder φ18650 - φ60140)
Yixinfeng independently develops a laser cutting system with absolute POS energy following algorithm. The stable production speed is 120m/min. The integrated machine can be adjusted by die-cutting and is compatible with AB battery cell winding. It has a wide compatibility range. This equipment can make all models of battery cells such as 18/21/32/46/50/60.

Ear Scrap Collection and Compaction Integrated Machine
This waste cabinet is a storage and extrusion integrated machine developed by our company specifically for the collection and compression of waste generated during the slitting or die-cutting process of positive and negative electrode materials for lithium batteries. It has the characteristics of simple operation, convenient waste discharge, small floor area, stable operation, and low noise. During the production process of lithium batteries, a certain amount of ear scrap will be generated. If it cannot be effectively collected and processed, it may affect the cleanliness of the production environment and may even cause safety hazards. By using the ear scrap collection and compaction integrated machine, waste on the production line can be cleaned up in time to keep the production environment clean and tidy, which is conducive to improving the safety and stability of production. Moreover, a relatively efficient waste collection method can reduce labor costs and time costs. From the perspective of resource recycling, compacted ear scrap is more convenient for subsequent processing and reuse, which is conducive to the recycling of resources and conforms to the concept of sustainable development.

Filter Element Automatic Cleaning Machine
The filter element automatic cleaning machine is a device used to clean filter elements. It usually uses a variety of technologies and functions to achieve efficient and thorough cleaning effects. The filter element automatic cleaning machine has the characteristics of simple operation and efficient cleaning, which can reduce costs and increase the service life of filter elements. It plays an important role in maintaining the good performance of lithium battery production equipment, ensuring product quality, controlling costs, and promoting the sustainable development of the industry.

Dust Removal Machine for Thousand-Grade Chip Manufacturing
This equipment adopts an online dust cleaning method. Through pulsed high-speed and high-pressure injection airflow to generate pressure bulging and micro-vibration to achieve the purpose of dust removal, and it repeats and circulates continuously. The dust removal machine for thousand-grade chip manufacturing provides a clean, safe, and stable environment for the production of lithium batteries by controlling dust, and plays an important supporting role in improving the quality, performance, and production efficiency of lithium batteries.