With the development of science and technology, lithium batteries have become an indispensable part of our daily life. From mobile phones and laptops to electric vehicles, lithium batteries are used everywhere. In order to produce high-quality lithium batteries, it needs to go through multiple processes such as the front, middle, and back sections, each of which is inseparable from the support of various equipment. This article will detail the main equipment of these three processes and their roles.
Lithium-ion battery is a complex system, including cathode, anode, separator, electrolyte, current collector and binder, conductive agent, etc., and the reactions involved include electrochemical reactions of positive and negative electrodes, lithium ion conduction and electron conduction, and heat diffusion. The production process of lithium battery is long, and there are many processes involved in the production process.
Lithium batteries can be divided into cylindrical batteries, prismatic batteries and pouch batteries according to their forms, and their production processes are different, but as a wholeThe lithium battery manufacturing process can be divided into the front-end process (pole piece manufacturing), the middle-end process (cell synthesis), and the back-end process (formation and packaging).。Due to the high safety performance requirements of lithium-ion batteries, there are extremely high requirements for the accuracy, stability and automation level of lithium-ion battery equipment in the battery manufacturing process.
Lithium battery equipment is the process equipment for manufacturing and production of positive and negative electrode materials, separator materials, electrolytes and other raw materials through an orderly process, and lithium battery equipment has a significant impact on the performance and cost of lithium batteries, which is one of the determining factors. According to different technological processes, lithium battery equipment can be divided into front-end equipment, middle-end equipment, and back-end equipmentIn the lithium battery production line, the value ratio of front, middle and back equipment is about 4:3:3.
The production goal of the pre-process is to complete the manufacture of (positive and negative) electrode pieces. The main processes of the front process are: mixing, coating, rolling, slitting, filming, die-cutting, and the equipment involved mainly includes: mixer, coating machine, roller press, slitting machine, tablet machine, die-cutting machine, etc.
Slurry mixing (equipment used: vacuum mixer)., equipment for mixing and homogeneously dispersing cathode and anode materials. It is to mix the positive and negative solid-state battery materials evenly and then add solvent and stir into a slurry. Slurry stirring is the starting point of the pre-process and the pre-sequence basis for completing the subsequent coating, rolling and other processes.
Coating (equipment used: coater)., a device used to apply positive and negative electrode materials to conductive agents. The stirred slurry is evenly coated on the metal foil and dried to make positive and negative electrode sheets. As the core link of the pre-process, the execution quality of the coating process profoundly affects the consistency, safety and life cycle of the finished battery, so the coating machine is the most valuable equipment in the pre-process.
Rolling (equipment used: roller press).Rolling refers to the process of compacting the lithium battery pole pieces that are coated and dried to a certain extent. After the pole piece is rolled, the energy density of the lithium battery can be increased, and the binder can be firmly attached to the electrode material on the current collector of the pole piece, so as to prevent the loss of lithium battery energy caused by the electrode material falling off from the electrode piece current collector during the cycle process. Rolling is one of the most critical processes in the manufacturing process of lithium battery pole pieces, and the accuracy of its rolling pressure greatly affects the performance of lithium batteries.
Slitting (equipment used: slitting machine).It is a narrow piece that continuously slits a wide whole roll of pole pieces into several required widths. The pole piece is fractured and failed by shearing during slitting, and the flatness of the edge after slitting (** thorn, no buckling) is the key to investigate the performance of the slitting machine. The equipment can quickly and accurately slitting lithium batteries of various specifications and shapes, making it an indispensable processing equipment on the lithium battery production line.
Production (equipment used: Tablet machine).It includes welding tabs to the slitted tabs, pasting protective tape, covering the tabs or using laser cutting to form the tabs, so as to be used in the subsequent winding process.
Die-cutting (equipment used: die-cutting machine).It is to punch and cut the electrode piece after coating for subsequent processing.
The production goal of the mid-stage process is to complete the manufacture of battery cellsThere are differences in the technical route and production line equipment of the middle process of different types of lithium batteries. The essence of the middle process is the assembly process, specifically the (positive and negative) electrode pieces made by the previous process, and the separator and electrolyte are assembled in an orderly manner. Due to the different energy storage structures of square (roll), cylindrical (roll) and pouch (layered) batteries, there are obvious differences in the technical routes and production line equipment of different types of lithium batteries in the middle process. Specifically, the main processes of the middle process of prismatic and cylindrical batteries are: winding, liquid injection, and packaging, and the equipment involved mainly includes: winding machine, liquid injection machine, packaging equipment (shell machine, groove rolling machine, sealing machine, welding machine), etc.;The main processes of the middle process of pouch batteries are: lamination, liquid injection, and packaging, and the equipment involved mainly includes: lamination machine, liquid injection machine, packaging equipment, etc.
Winding (equipment used: winder).The lithium battery winding machine is used to wind the lithium battery cell, which is a machine that assembles the positive electrode piece, negative electrode piece and separator of the battery into a core package in a continuous rotation manner. The winding machine has a positive and negative electrode feeding unit, and the part that winds the positive and negative diaphragms together is called a needle winding. According to the different shape types of winding core packs, winding equipment can be mainly divided into two categories: square winding and cylindrical winding. Square winding can be subdivided into two categories: square automatic winding machine and square film making and winding machine, and the cells that are coiled out of square are mainly used to make power energy storage square batteries, digital batteries, etc.
Winding (equipment used: winder).The lithium battery winding machine is used to wind the lithium battery cell, which is a machine that assembles the positive electrode piece, negative electrode piece and separator of the battery into a core package in a continuous rotation manner. The winding machine has a positive and negative electrode feeding unit, and the part that winds the positive and negative diaphragms together is called a needle winding. According to the different shape types of winding core packs, winding equipment can be mainly divided into two categories: square winding and cylindrical winding. Square winding can be subdivided into two categories: square automatic winding machine and square film making and winding machine, and the cells that are coiled out of square are mainly used to make power energy storage square batteries, digital batteries, etc.
Liquid injection machine (equipment used: liquid injection machine).It is used to inject the electrolyte into the battery electrode piece to complete the electrochemical reaction of the battery.
Cell packaging (equipment used: shelling machine, grooving machine, sealing machine, welding machineIt is to put the core into the cell housing.
The production goal of the back-end process is to complete the formation and packaging。As of the middle process, the functional structure of the lithium battery cell has been formed, and the significance of the later process is to activate it, and after testing, sorting and assembly, it will form a lithium battery product that is safe to use and has stable performance. The main processes of the back-end process are: formation, capacities, testing, sorting, etc., and the equipment involved mainly includes: charging and discharging motors, testing equipment, etc.
Formation (equipment used: charging and discharging motors)., which is used to charge and discharge the battery to evaluate the performance and safety of the battery, is to activate the battery cell through the first charge, and in this process, an effective passivation film (SEI film) is generated on the surface of the negative electrode to achieve the "initialization" of the lithium battery.
Capacity (equipment used: charging and discharging motors).In other words, the "analytical capacity" is to charge and discharge the formed battery cells according to the design standards to measure the capacitance of the cells. The charging and discharging of the battery cell runs through the formation and capacity separation process, so the charging and discharging motor is the most commonly used back-end core equipment. The minimum working unit of the charging and discharging motor is the "channel", and a "box" (box) is composed of several "channels", and a plurality of "units" are combined together to form a charging and discharging motor.
Testing (equipment used: testing equipment).It should be carried out before and after charging, discharging, and standingSorting is based on the test results to classify and select the formed and capacitated batteries according to certain standards. The significance of the detection and sorting process is not only to eliminate unqualified products, because in the practical application of lithium-ion batteries, the battery cells are often combined in parallel and series, so the selection of cells with close performance will help to optimize the overall performance of the battery.
The production of lithium batteries is inseparable from lithium battery production equipment, and its performance is determined by the manufacturing process and production equipment. China's lithium battery equipment companies have surpassed Japanese and South Korean equipment companies in terms of technology, efficiency, and stability, and have advantages such as cost performance and after-sales maintenance. A cluster of domestic lithium battery equipment enterprises has been formed, which has become the business card of China's high-end equipment and entered the international market. With the vertical alliance of lithium battery leaders and the expansion of overseas production, lithium battery equipment has ushered in a new period of opportunity for rapid growth.