Lithium battery production process

Lithium-ion battery is a complex system, including positive electrode, negative electrode, diaphragm, electrolyte, collector, binder, conductive agent and so on. The reactions involved include electrochemical reactions of positive and negative electrodes, lithium ion conduction and electron conduction, heat diffusion, etc. The production process of lithium battery is long. Lithium battery production process is long, involving more than 50 processes.

Lithium batteries can be divided into cylindrical batteries, Lithium battery recyclingquare batteries and flexible packaging batteries according to their forms, and their production processes are somewhat different, but the whole process can be divided into the first part of the process (electrode manufacturing), the middle part of the process (battery synthesis), and the second half of the process (packaging). Due to the high safety requirements of lithium-ion batteries, the process of manufacturing lithium-ion batteries requires a high degree of precision, stability and automation.

Lithium battery equipment is a kind of process equipment for manufacturing raw materials such as positive and negative electrode materials, diaphragm materials, electrolyte and other raw materials through an orderly process. Lithium battery equipment has a significant impact on the performance and cost of lithium battery and is one of the decisive factors. According to different process flow,battery production line lithium battery equipment can be divided into front-end equipment, intermediate equipment and back-end equipment. In the lithium battery production line, the value ratio of front-end equipment, intermediate equipment and back-end equipment is about 4:3:3.

Lithium battery manufacturing enterprise process machine learning equipment

The process of the first stage of the production goal is to complete (positive and negative) plate manufacturing. The main processes in the first stage are: mixing, coating, rolling, cutting, film making, die cutting, and the equipment involved are: mixer, coater, roller press, slitter, film making machine, die cutting machine labeling machine.

Slurry mixing (equipment used: vacuum mixer) is to mix the positive and negative solid state battery materials, and then add solvent mixing into slurry. Slurry mixing is the starting point of the previous process, and is the basis for completing the subsequent coating and roller pressing processes.

Coating (for equipment: coating machine) is to mix the slurry evenly coated on the metal foil, and then dried into positive and negative sheet. As the core of the pre-process, the quality of the coating process has a profound impact on the consistency, safety and life cycle of the finished battery, making the coating machine the most valuable piece of equipment in the pre-process.

Rolling (equipment used: roller press) is used to further compact the coated pole piece, thus increasing the energy density of the battery. The flatness of the pole piece after rolling will directly affect the processing effect of the subsequent cutting process, and the uniformity of the active substance of the pole piece will indirectly affect the performance of the battery.

Roller press principle

Slitting (technical equipment used: slitting machine) is a continuous longitudinal cutting of a wide roll of poles into a number of narrow pieces of the required time width. The pole piece in the slitting encountered in the shear damage effect and fracture control failure, after slitting the edge of the flat open degree (no burr, no flexing) is the examination of the performance of the slitting machine to analyze the advantages and disadvantages of the key.

Slitter principle

Said filter comprises welding said filter sheet, applying protective tape, bonding said filter sheet or laser cutting and forming said filter sheet for use in a subsequent winding process. Die-cutting (for equipment: die-cutting machine) involves die-cutting the coating to form a column for subsequent processing.

Principle of the die cutting machine

The production goal of the intermediate stage process is to complete the manufacture of the battery. There are differences in the technical routes and production equipment for the intermediate stage process for different types of lithium batteries. The essence of the intermediate process is the assembly process, specifically the orderly assembly of the (positive and negative) pole pieces made in the previous process with the diaphragm and electrolyte. Due to the different energy storage structures of square (rolled), cylindrical (rolled) and flexible (laminated) batteries, there are obvious differences in the technical routes and production equipment of different types of lithium batteries in the intermediate process. Specifically, the main processes in the intermediate process of square and cylindrical batteries are winding, liquid injection and packaging, involving equipment mainly winding machines, liquid injection machines and packaging equipment (shelling machines, slot rolling machines, sealing machines and welding machines). The main processes in the intermediate stage of flexible batteries are lamination, liquid injection and packaging, and the equipment involved mainly includes laminating machines, liquid injection machines and packaging equipment.

Winding (for equipment: winding machine) is the process of manufacturing or winding die-cutting machine, made by winding into lithium-ion battery pole pieces, mainly used in the production of square, round lithium batteries. Winding machines can be subdivided into two categories: square winding machines and cylindrical winding machines, which are used for the production of square lithium batteries and cylindrical lithium batteries respectively. Compared with cylindrical winding, the square winding process requires higher tension control, so the square winding machine is more difficult.

Principle of winding machine

Lamination (equipment used: laminating machine) is to stack the monopoles made in the die-cutting process into lithium-ion battery cells, mainly used in the production of soft pack batteries. Compared with square and cylindrical batteries, flexible pack batteries have obvious advantages in energy density, safety and discharge performance. However, the single stacking task of the laminator involves the parallelism of multiple sub-processes and the cooperation of complex mechanisms, which need to deal with complex dynamic control problems to improve the efficiency of lamination; while the speed of the winder is directly related to the winding efficiency, and the means to improve efficiency are relatively simple. At present, the production efficiency and output of laminated batteries are different from that of wound batteries.

Liquid injection machine (the technical equipment used: liquid injection machine) is a quantitative study of the electrolyte of the battery is injected into the electric cell.

Liquid injection machine principle

Core packing (equipment used: shelling machine, slotting machine, sealing machine, welding machine) is to put the core into the core shell.

Welding machine principle

The production goal of the latter process is to complete the chemical formation and packaging. By the middle process, the functional structure of the core has been formed, and the significance of the later process is to activate it, after testing, finishing and assembling, to form a finished lithium battery with safe use and stable performance. The main processes in the later stage are: molding, volume separation, testing, sorting and so on. The main equipment involved: charging and discharging motor, testing equipment, etc..

Formation (device: charger/discharger) is activated by the first charge of the battery, the formation of an effective passivation film on the surface of the negative electrode (SEI film) in the process of realizing the "initialization" of the lithium battery. The secondary capacity (equipment used: charger/discharger) is the "analyzed capacity", which is converted into a battery according to the charging/discharging design criteria to measure the capacity of the battery. The charging and discharging process of the battery takes place throughout the formation and distribution of the battery's capacity, so the charger/discharger is the most commonly used back-end core device. The smallest unit of the charger/discharger is the "channel", a "unit" (BOX) by a number of "channel" combined, multiple "units A "unit" (BOX) consists of several "channels", and several "units" are combined to form a charger/discharger.

Testing (used equipment: test equipment) should be carried out before and after charging and discharging, static; sorting is based on the test results, in accordance with certain standards for the chemistry, after the division of the battery classification, selection. The significance of the testing and sorting process not only lies in the elimination of unqualified products, but also in the selection of similar performance of the cell to optimize the overall performance of lithium-ion batteries, because the actual application of the cell is often combined in parallel or series.

Lithium battery production and life can not be separated from the lithium battery production and management equipment, in addition to the materials used in the battery system itself, the manufacturing process and production and equipment is to determine the performance of the battery is an important factor affecting. In the early days, China's lithium equipment companies can mainly rely on imports, after a few years of rapid economic development, China's lithium equipment to achieve enterprises in technology, efficiency, stability and many different aspects have begun to gradually catch up with Japan and South Korea equipment for the enterprise, and has the cost-effective, after-sales maintenance of the community and other aspects of the advantages. At present our domestic lithium equipment requirements enterprise culture cluster has not formed, and become with China's high-end equipment business card into the university international financial market. With the lithium leading vertical alliance with the sea expansion, lithium equipment to benefit from downstream expansion ushered in a new period of opportunity for rapid and stable growth.

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