What is Lithium Cell Production Line and Why Do We Use Them?

When discussing lithium batteries, it is impossible to avoid focusing on their essential component, namely, the cells of which they are composed and which enable them to deliver power. The three most widely used lithium ion cell types, each employed for a distinct kind of application, are as follows:

Check now

Cylindrical lithium cells

As can easily be inferred, cylindrical cells are cylinder-shaped, are the most commonly used and were among the first to be mass-produced. They can have different diameters, the most common being the , where the number 18 indicates the diameter (18 mm) and the number 65 indicates the length (65 mm). There are, however, other formats, such as the or, again, the one most recently adopted by Tesla, the pioneer of lithium batteries for electric cars, with its used to power the Tesla Model Y. Apart from a few car manufacturers who have made this choice, cylindrical cells are routinely used in medium-small battery packs, e.g. in micro-mobility (bikes, scooters and motor scooters), portable tools, medical devices, and so on.

Lithium pouch cells

These types of lithium cell are so called because of their bag-like shape. They have a lightweight design and, as they have no inherent robustness, special protections, such as the addition of aluminium frames, must be inserted during production of the module to give them structural robustness. They come in various sizes which can be modified according to the manufacturer's requirements. These cells are mainly used in smartphones, drones, laptops and the automobile industry.

Prismatic lithium cells

Prismatic lithium cells have a solid rectangular casing made of aluminium or of a very strong plastic material. The internal components are layered. They come in different sizes, with a variety of formats depending on the field of application. Their individual components can reach a high capacity. Due to their structure, prismatic cells are best suited for the production of lithium batteries for the machinery and industrial vehicles industry, or the energy storage sector, all of which normally require medium-high capacities.

The benefits and drawbacks of the various cell types have already been discussed, but few people ever enquire about the lithium-ion battery cell production process and how it works.

Although the many cell types that make up a lithium battery appear very different from one another when viewed from the outside, it is astonishing to learn how similar their interiors actually are. The different types of battery cell production and assembly will now be explored in more detail.

The process begins with combining the raw materials of which the lithium cells are composed

As has already been illustrated, the assembly methods may be different, but the battery cell composition remains the same. In the images of the various assembly processes can be seen how the anode has a basic brown colour, as the coating is deposited on a thin layer of copper. Then comes the plastic or ceramic separator, and finally, the cathode, which is grey in colour, since it is deposited on a layer of aluminium.

What are the pros and cons of the different cell assembly methods?

At the time of writing, no one technology prevails over the others in lithium ion cell production. Each manufacturer has a favoured methodology and each will argue the merits of its choice according to the end use of the lithium battery taken as a whole.

What can be said, however, is that the stacking method makes good use of the space on a rectangular cell (pouch or prismatic). This is because, positioned in this way, the sheets manage to fill all spaces perfectly, thus increasing the active area. Nevertheless, the stacking method carries two types of risk:

1. if the sheets are slightly out of alignment, the separator in particular may be unable to avoid contact at the edges of the two electrodes, leading to short circuits;
2.  even if a laser is used, sheet cutting might still result in imperfections or could damage the edges, all of which leads to yet another difficult-to-control factor in cell quality.

In contrast, rolling or folding systems give a better guarantee of separation between components, since there are no gaps in the separator. The disadvantage, in this case, lies at the bending or curving point, which is subjected to greater mechanical stress and thus runs a greater risk of rupture, causing the two electrodes to short-circuit.

Furthermore, in the rolling method, the end result is a more or less oval-shaped roll, meaning that the corners of the rectangular cell contain no material and hence that less use will be made of the inner volume. For this very reason, even large cells are often made by placing several smaller rolls parallel to each other inside the cell.

What does the structure of a lithium cell look like after assembly?

[Fig. 1]*

The above image gives a clear example of the internal lithium battery cell composition, before it is placed into its containment case and used in modules to create the complete lithium battery pack. In this specific case, one is dealing with a prismatic cell, where two 'small packs' are held in place by a central ribbon (yellow).

In the centre can be seen the separator (white), while to the right and left are the cathode (copper) and anode (aluminium), which will then be connected to the external terminals of the cell by means of ultrasonic welding.

The animation shows the various stages of cell filling, an operation that at first glance seems simple, but which in fact is a particularly delicate and costly process requiring numerous steps. A liquid containing lithium salts is inserted into the central hole. The stack gradually absorbs it by means of capillary action. Where liquid is actually needed is in the middle of the cell, between the two electrodes and the separator.

Filling is an extremely slow process, since, in order to allow the liquid to be absorbed without leaking, the cell needs to be filled at various times. Suffice to say that the final filling is done after an aging period of several days. Prior to the final sealing, a filling level control phase is carried out by weighing the cell. This step is essential and absolutely necessary, as once the cell is completely sealed the hole will be closed and no longer accessible.

Lithium cell assembly is only one piece of the puzzle

Correct assembly of the cells that make up a lithium battery, whether such cells are prismatic, cylindrical or of the pouch type, is therefore an extremely complex operation, requiring long machinery set-ups as well as the utmost precision at every stage, an essential element to ensure safety, quality and reliability over time. Because of the regular and stringent inspections for contaminants and the need for uninterrupted operations in cleanrooms, this process requires huge investments as well as expansive facilities.

After the choice of the most suitable lithium chemistry, correct cell assembly is without doubt the first step (of a long series) required to achieve complete efficiency of a lithium battery. It is a complex chain of actions that ranges from the creation of the module to the implementation of state-of-the-art control electronics with advanced BMS, and culminating in the development of battery packs with increasingly advanced architectures.

Each electrical application has its own unique specifications, and in order to ensure proper operation it is crucial to strike the right balance between all of these components which, like pieces of a jigsaw puzzle, must be expertly positioned to create the product's identity, something that can only be ensured by a skilled and consolidated manufacturer.

Welcome to our informative article on the manufacturing process of lithium batteries. In this post, we will take you through the various stages involved in producing lithium-ion battery cells, providing you with a comprehensive understanding of this dynamic industry.

Lithium battery manufacturing encompasses a wide range of processes that result in the production of efficient and reliable energy storage solutions. The demand for lithium batteries has surged in recent years due to their increasing application in electric vehicles, renewable energy storage systems, and portable electronic devices.

The production of lithium-ion battery cells primarily involves three main stages: electrode manufacturing, cell assembly, and cell finishing. Each stage comprises specific sub-processes to ensure the quality and functionality of the final product.

The first stage, electrode manufacturing, is crucial in determining the performance of the battery. It includes various processes such as mixing the electrode materials with a conductive binder, coating the slurry onto current collectors, and calendaring to adjust the physical properties of the electrodes.

In the second stage, cell assembly, the electrode assemblies are layered with a separator, connected to terminals or cell tabs, and inserted into a cell housing. This stage is predominantly carried out on highly automated equipment and plays a vital role in ensuring the structural integrity of the battery.

The final stage, cell finishing, involves the formation process, aging, and end-of-line testing to guarantee optimal battery performance. Once the cells pass the stringent quality standards, they can be assembled into battery packs based on specific requirements.

The lithium battery manufacturing industry is dominated by countries like China, Japan, and South Korea, which are major manufacturers and suppliers of equipment for lithium-ion cell production. These countries continually invest in research and development to drive innovation in battery technology, resulting in improved performance, cost reduction, and better quality products.

Innovation plays a pivotal role in advancing lithium battery manufacturing processes. From improved mixing technologies to efficient coating processes, these innovations contribute to the growth of lithium battery technology and further strengthen the battery manufacturing industry.

Stay tuned for our upcoming sections where we delve deeper into the electrode manufacturing, cell assembly, and cell finishing stages of the lithium battery manufacturing process. We will explore the equipment used, key techniques, and the significance of each stage in detail.

Qingtao Product Page

Electrode Manufacturing in the Lithium Battery Manufacturing Process

In the lithium battery manufacturing process, electrode manufacturing is the crucial initial step. This stage involves a series of intricate processes that transform raw materials into functional electrodes for lithium-ion batteries. Let's explore the intricate details of this crucial stage in the production line.

Mixing the Electrode Materials

The first step in electrode manufacturing is the precise mixing of electrode materials. This process blends crucial components, such as lithium compounds and conductive additives, to form a homogeneous mixture. Achieving the perfect blend ensures the electrode's performance and overall battery efficiency.

Formation of Slurry

Once the materials are mixed, a conductive binder is introduced to create a slurry. This slurry-like substance facilitates the coating process during the next stage. It plays a crucial role in maintaining the structural integrity and conductivity of the electrode.

Coating onto Current Collectors

The slurry is then evenly coated onto current collectors, typically made of copper or aluminum foil. A controlled application ensures uniformity, thickness, and optimal adhesion of the electrode material. This coating process forms the foundation of the electrode's structure.

Drying and Calendaring

After coating, the foils are subjected to a drying process to remove solvents and moisture. This step ensures the integrity of the electrode structure and prevents potential defects. Subsequently, calendaring machines apply pressure to adjust the physical properties of the electrodes, enhancing their mechanical stability.

Cleaning and Cutting

Once the electrodes are finished, they undergo a cleaning process to remove any residual impurities or contaminants. Then, they are meticulously cut into narrow strips, preparing them for the subsequent stages of the battery production line.

Vacuum Oven Treatment

Finally, the cut electrodes are sent to a vacuum oven for thorough drying. The controlled environment within the vacuum oven removes any remaining moisture, ensuring the electrodes' optimal performance and quality.

The electrode manufacturing stage heavily relies on advanced and precise equipment to achieve high-quality electrodes efficiently. Mixers, coating and drying machines, calendaring machines, and electrode cutting machines are some of the essential lithium battery manufacturing equipment employed during this process.

Cell Assembly in the Lithium Battery Manufacturing Process

During the cell assembly stage of the lithium battery manufacturing process, we carefully layer the separator between the anode and cathode. This can be done through stacking or winding techniques, depending on the battery design. To ensure a secure connection, we employ processes like ultrasonic or laser welding to attach terminals or cell tabs to the assembled cell structure.

Once the sub-assembly is complete, it is inserted into the cell housing. We seal the housing using laser welding or heating methods to prevent any leakage or external interference. In preparation for the next step, we fill the housed cell with electrolyte in a controlled, dry room environment. The electrolyte port is then closed to maintain the integrity of the cell.

Cell assembly is a highly automated process that relies on advanced equipment. Battery manufacturing companies play a crucial role in this stage by providing the necessary machinery and technology. Their expertise ensures smooth and efficient assembly, resulting in high-quality lithium batteries.

By paying attention to every detail of the cell assembly process, we can maintain the integrity and performance of the lithium battery. The precision and automation involved in this stage contribute to the overall reliability and durability of the final product.

Cell Finishing in the Lithium Battery Manufacturing Process

Cell finishing is a crucial stage in the lithium battery manufacturing process. It involves several key processes that ensure the quality and performance of the battery cells before they are assembled into battery packs.

The first step in cell finishing is the formation process, where the battery cells undergo their initial charging and discharging cycles. This process is essential as it helps establish a protective layer between the electrolyte and the electrodes, optimizing the battery's overall performance and lifespan.

Once the formation process is complete, the cells undergo aging to further evaluate their characteristics and performance. This step is critical in ensuring that the cells meet the required quality standards, as any deviations or inconsistencies can impact the battery's functionality and safety.

After the aging process, end-of-line (EOL) testing is conducted to comprehensively assess the cells' performance and ensure they meet the specified industry standards. These tests include a series of evaluations, such as capacity testing, impedance analysis, and temperature cycling, to verify the cells' reliability and performance under various conditions.

Upon successful completion of the EOL testing, the cells are ready to be assembled into battery packs. This final stage of the lithium battery manufacturing process involves arranging the cells according to specific requirements, such as series or parallel connections, to achieve the desired voltage and capacity.

To carry out these processes efficiently and effectively, battery manufacturing companies provide specialized equipment. Some of the commonly used equipment in this stage includes battery formation testers, aging cabinets, and battery testing machines. These advanced tools and machinery contribute to the seamless production of high-quality lithium batteries.

Innovation in Cell Finishing

The field of cell finishing is constantly evolving with technological advancements and innovation. Battery manufacturing companies are continuously exploring new methods and technologies to improve the efficiency and performance of this crucial stage. Some notable innovations in cell finishing include:

Improved formation techniques: Advanced battery formation techniques enhance the formation process, leading to improved battery performance and reliability.

Automated aging systems: Automation in aging cabinets streamlines the aging process, reducing manual labor and ensuring consistent and accurate results.

Enhanced EOL testing methods: Innovative testing methods, such as non-destructive testing and predictive analysis, enable faster and more accurate evaluation of cell performance.

These innovations not only optimize the cell finishing stage but also contribute to the advancement of the overall lithium battery manufacturing industry. The continuous drive for innovation fosters the production of more efficient, reliable, and environmentally friendly lithium batteries, catering to the increasing demands of various industries and applications.

Innovation in Lithium Battery Manufacturing Processes

In the fast-paced world of lithium battery manufacturing, innovation is the key to success. As technology and materials continue to advance, we are witnessing significant improvements in cost reduction, performance enhancement, and overall product quality. These innovations not only benefit the lithium battery technology itself but also have a profound impact on the growth and development of the battery manufacturing industry.

One area of innovation lies in the various mixing technologies and tools used in the manufacturing process. These advancements enable manufacturers to achieve a more uniform distribution of active materials, resulting in batteries with improved efficiency and energy storage capabilities. Additionally, simultaneous coating processes have been introduced to enhance production efficiency, enabling multiple layers to be applied in a single pass, reducing cycle times while maintaining consistent quality.

Furthermore, dry coating applications without solvents have emerged as a greener alternative. By eliminating the need for solvents, manufacturers can reduce environmental impact and streamline the production process. Infrared heating technology is another innovative solution that enhances conventional drying methods by increasing efficiency and reducing energy consumption.

Last but not least, lamination techniques have revolutionized the production line speed. By adopting advanced lamination processes, manufacturers can achieve faster assembly times without compromising the integrity of the batteries. This ensures timely delivery of high-quality lithium batteries to meet the growing demands of various industries.

Are you interested in learning more about Lithium Cell Production Line? Contact us today to secure an expert consultation!