What are the manufacturing processes for 18650 lithium-ion batteries?
Lithium ion battery manufacturing process: three processes in the front, middle, and back, accounting for nearly 35%/30%/35%
The production process of lithium-ion batteries is relatively complex. The primary production process includes the stirring and coating stage (front stage) of electrode manufacturing, the winding and liquid injection stage (middle stage) of battery cell composition, and the packaging and testing stage (rear stage) of chemical packaging. The value (purchase amount) accounts for about (35-40%): (30-35)%: (30-35)%. The differences mainly come from different equipment suppliers, differences in import/domestic ratios, etc. The process flow is common, and the proportion of value and quantity may have errors, but overall it conforms to this proportion.
The lithium battery equipment corresponding to the front-end process of lithium battery production mainly includes vacuum mixers, coating machines, roller presses, etc; The intermediate process mainly includes die-cutting machine, winding machine, laminating machine, liquid injection machine, etc; The later stages of the process include chemical conversion machines, volume separation testing equipment, process warehousing and logistics automation, etc. In addition, the production of battery packs also requires Pack automation equipment.
Lithium battery front-end production process: electrode manufacturing Contact battery center Function
The result of the front-end process of lithium-ion batteries is the completion of the preparation of the positive and negative electrode sheets. The first step is stirring, which involves mixing the solid battery materials of the positive and negative electrodes evenly and adding solvents. The mixture is then stirred into a slurry using a vacuum mixer. The mixing of ingredients is the foundation of the subsequent process of lithium batteries, and high-quality mixing is the basis for the high-quality completion of subsequent coating and rolling processes.
After the coating and rolling process, it is cut, that is, the coating is subjected to a cutting process. If burrs occur during the slitting process, safety hazards may arise in subsequent equipment, electrolyte injection procedures, and even battery usage processes. Therefore, the front-end equipment in the lithium battery production process, such as mixers, coating machines, roller presses, slitting machines, etc., are the central machines in battery manufacturing, which are related to the quality of the entire production line. Therefore, the value (amount) of front-end equipment accounts for the highest proportion of the entire lithium battery automation production line, about 35%.
Lithium battery intermediate process flow: power first, winding before stacking
In the manufacturing process of lithium-ion batteries, the primary intermediate process is to complete the formation of the battery. The primary process includes sheet making, pole piece winding, die-cutting, cell winding and forming, and laminated forming. It is currently a fiercely competitive field among domestic equipment manufacturers, accounting for about 30% of the value of lithium-ion battery production lines.
At present, the manufacturing process of power
lithium-ion batteries mainly includes winding and stacking, and the corresponding battery structure methods are mainly cylindrical and square, and soft pack. Cylindrical and square batteries are mainly produced by winding process, while soft pack batteries are mainly produced by stacking process. Cylinders are mainly represented by 18650 and 26650 (Tesla has independently developed 21700 batteries and is currently implementing them). The difference between square and soft packaging is that the outer shell is made of hard aluminum shell and aluminum-plastic film, respectively. Among them, the soft packaging is mainly made of laminated technology, while the aluminum shell is mainly made of winding technology.
The soft pack structure method is primarily aimed at mid to high end digital shopping malls, with higher profit margins per unit product. Under equal production conditions, the relative profit is higher than that of aluminum shell batteries. Due to the planning effect of aluminum shell batteries, the product qualification rate and cost are easy to control, and both have considerable profits in their respective market fields. In the foreseeable future, it is difficult for both to be completely replaced.
Due to the fact that the winding process can achieve high-speed production of battery cells through rotational speed, while the speed at which the laminating technology can advance is limited, the winding process is currently the primary choice for domestic power lithium-ion batteries. Therefore, the shipment volume of winding machines is now greater than that of laminating machines.
The corresponding preceding processes for winding and laminating production are the production of polarizer sheets and die cutting. Production includes welding the segmented pole pieces/pole ears, removing dust from the pole pieces, applying protective tape, wrapping the pole ears with glue, and winding or cutting to a fixed length. The winding pole pieces are used for subsequent fully automatic winding, while the cutting pole pieces are used for subsequent semi-automatic winding; Punching and cutting pole pieces are formed by winding and punching the segmented pole pieces, which are used for subsequent laminating processes.
In terms of lithium battery packaging and welding, mainstream laser technology integrated application manufacturers such as Lianying, Dazu, and Guangda are all involved, which can meet the demand without the need for imports.
The process flow of lithium battery in the later stage: capacitive conversion is the central link
The production process of lithium batteries in the later stage mainly consists of four processes: capacity separation, chemical conversion, testing, and packaging, accounting for about 35% of the value of the production line. Chemical conversion and capacity separation are the most important steps in the later stage of the process, which activate and detect the formed battery. Due to the long charging and discharging test cycle of the battery, the value of the equipment is the highest. The primary purpose of the chemical conversion process is to charge and activate the encapsulated battery cells, while the capacity separation process tests the battery capacity and other electrical parameters after activation and classifies them. The conversion and capacity separation are usually completed by an automated capacity separation system, with the conversion machine and capacity separation machine respectively.
Lithium Battery Pack Process: Seemingly Simple but Combined with Systematic Planning Requirements
The power lithium battery pack system is a battery pack that connects many individual cells in series or parallel, summarizing battery hardware systems such as power and thermal management. Pack is the key to the production, planning, and application of power lithium battery systems. It is the central link connecting upstream battery cell production and downstream vehicle application. Generally, the planning requirements are proposed by battery manufacturers or car manufacturers, and are usually completed by battery manufacturers, car manufacturers, or third-party pack factories.
The lithium-ion battery pack production line is relatively simple, with central processes including feeding, bracket bonding, welding, and testing. The central equipment includes laser welding machines and various bonding and testing devices. Currently, major lithium battery equipment manufacturers have limited automation integration layouts in this field, while laser equipment manufacturers such as Dazu Laser and Lianying Laser have a higher market share in the Pack equipment field due to their absolute advantage in the laser field.
