Production of 18650 cylindrical battery related equipment introduction
18650 is a type of lithium-ion battery, the common 18650 battery is also divided into lithium-ion batteries and lithium iron phosphate batteries, 18650 in 18 refers to the diameter of the lithium-ion battery is 18mm, 65 indicates the length value of 65mm, 0 indicates that it belongs to the cylindrical battery. Capacity is 31.5ah and voltage is 3.6v. It is a very cost-effective battery.
The production process of lithium battery is long, and there are more than 50 processes involved in the production process, and the failure of any link will affect the performance of lithium-ion battery cells or bring safety problems.
The manufacturing process of 18650 lithium-ion battery is shown as follows:
Required equipment
The main process of the first section of the process is: mixing, coating, rolling, scuttling, production, die cutting, the equipment involved mainly includes: mixer, coating machine, roll press, scuttling machine, production machine, die cutting machine, etc.
1）Mixing machine:
Vacuum mixer is a set of dispersion, mixing as one, suitable for polymer lithium-ion battery liquid and liquid lithium battery liquid, electronic battery slurry, adhesive, mold glue, solid and liquid materials mixing, reaction, dispersion, dissolution, homogenization, emulsification and other processes.
The main purpose of coating is to coat the slurry with good stability, good viscosity and good fluidity evenly on the surface of the positive and negative electrodes. Its important significance for lithium batteries is mainly reflected in three aspects: consistency, cycle life and safety.
During the coating process, if the thickness of the positive and negative slurry coating at the front, middle and back of the pole plate is inconsistent, or the parameters before and after the pole plate are inconsistent, it is easy to cause the battery capacity to be too low or too high, and lithium evolution may be formed during the battery cycle, affecting the battery life.
Coater is the core equipment of the previous process. The coater has undergone the evolution of three structural types, namely, scraper type, transfer type and slit extrusion type. The technological advanced degree of coating machine equipment is mainly investigated in four aspects: coating technology, tension technology, correction technology, drying technology.
Coating efficiency is an important standard for leading enterprises to further compete technical strength. Under the premise of ensuring the above technology, the current leading coater equipment mainly focuses on improving the coating efficiency, the main means include improving the running speed and coating width of the coater, the leading company's coating speed can reach 120m/min, and the coating width can reach 1400mm.
The production goal of the middle process is to complete the manufacturing of the battery cell, the main process is: winding, injection, packaging, the equipment involved mainly includes: winding machine, injection machine, packaging equipment (shell machine, rolling slot machine, sealing machine, welding machine).
Tension control is the core technology that affects the advanced degree of the winding machine. During the entire winding process, in order to ensure that the battery assembled from the cell has high consistency, special attention should be paid to the tension control of the winding.
For the winding of the square lithium battery, the line speed of the winding needs to be kept unchanged, and the angular speed needs to be automatically adjusted, so the tension control of the square lithium battery winding has higher technical requirements. At present, domestic leading enterprises can achieve cylindrical battery tension fluctuation control below 5%, square battery tension fluctuation control below 10%.
The automatic correction technology and winding speed of the winding machine are also more critical. The correction system can ensure that the electrode sheet diaphragm is neatly wound during the battery winding process, and the relative position between the positive/negative electrode/diaphragm is accurate. At present, the industry usually requires that the upper and lower deviation of the positive and negative electrode sheet or diaphragm after the winding is less than 0.5mm, and more than this value will affect the battery deformation.
At present, the cylindrical cell of the domestic leading enterprises can reach a high-speed winding speed of more than 18 meters/second, and the square cell needs to ensure the constant line speed, so the variable angular speed winding is slower, and the domestic leading enterprises can reach more than 0.8 meters/second.
The laser welding machine uses high-energy laser pulses to locally heat the material in a small area, and the energy of laser radiation diffuses to the interior of the material through thermal conduction, melting the material to form a specific melt pool.
It is a new type of welding, laser welding is mainly for thin-wall materials, precision parts welding, can achieve spot welding, butt welding, overlap welding, sealing welding, depth to width ratio, welding width is small, heat affected zone is small, small deformation, welding speed, smooth weld, beautiful.
No processing or simple processing after welding, high quality weld, no porosity, accurate control, small focus spot, high positioning accuracy, easy to achieve automation.
The main processes in the latter part of the process are: formation, volume separation, detection, sorting, etc. The equipment involved mainly includes: charging and discharging machine, testing equipment, etc.
The chemical composition and testing system is the most critical link in the latter process. The chemical component of the lithium battery cell is to achieve the initial initiation of the battery by charging and discharging, so that the active substance of the cell is activated, which is a process of energy conversion.
5）Charge and discharge machine
Charge and discharge machine is the key equipment in the chemical component capacity, and it is also the most used equipment in the latter part. The minimum working unit of the charge and discharge machine is the "channel". A channel can charge or discharge a cell. In the actual use of charge and discharge machines, a "unit" is composed of a certain number of channels (such as 24, 32, 64, etc.).
The "unit" contains a number of "channels", which is the smallest unit when the charge and discharge mechanism is built and installed, and the Japanese and Korean companies call this unit BOX. In principle, a charging and discharging machine can be composed of countless boxes, under the influence of more manual operation habits in China, the number of boxes of a charging and discharging machine is generally not large, and a production line often needs more than a dozen to hundreds of charging and discharging machines.
