Overview of battery equipment processing

The production process of lithium battery cells is divided into three stages: front, middle and back. The purpose of the front stage is to process the raw materials into pole pieces, and the core process is coating; the middle stage is to process the pole pieces into non-activated cells; The back process is detection and packaging, and the core process is formation and volume separation.
According to the battery production and manufacturing process, lithium battery equipment is divided into front-end equipment, middle-stage equipment, and back-end equipment.
The value of the front-end equipment accounts for about 40%, of which the value of the coating machine accounts for 75%, and the value of the roller press is greater than that of the slitting machine. Ternary materials have higher performance requirements for front-end equipment, and the value of front-end equipment will gradually increase.
The value of the middle-stage equipment accounts for about 30%, of which the value of the winding machine accounts for 70%. At present, the market concentration of winding machine is relatively high, with CR3 reaching 60%-70%.
The value of the back-end equipment accounts for about 30%, of which the chemical composition system accounts for 70% and the assembly accounts for 30%.
After the production of the battery cell is completed, the pack process is carried out to form the finished product, which is what we call the battery. The main processes of the Pack process include welding, labeling, performance testing, size testing, liquid leakage detecting, etc. The value of pack equipment is smaller than that of cell equipment, accounting for about 5%~10% of cell equipment

Mixing process

Using a lithium battery vacuum mixer, with the action of a special solvent and a binder, the powdered positive and negative active materials are mixed, and after high-speed stirring, a slurry of positive and negative electrodes without bubbles is made.

Coating process

The coating machine is the core equipment of the previous process. The main purpose of coating is to uniformly coat the slurry with good stability, good viscosity and good fluidity on the surface of the positive and negative electrodes. The coating process must strictly ensure that no particles, sundries, dust, etc. are mixed into the pole piece. If the sundries are mixed in, it will cause a micro short circuit inside the battery, which will cause the battery to catch fire and explode in severe cases.

Calendering process

The function of Calendering is to compact the pole pieces and improve the energy density of the battery. After the pole piece is coated and dried in the previous process, the active material and the foil are easily peeled off. Therefore, it is necessary to roll the active material to enhance the bonding strength of the active material and the foil, The compaction density can increase the discharge capacity of the battery, reduce the internal resistance, reduce the polarization loss, prolong the cycle life of the battery, and improve the utilization rate of the lithium-ion battery. The calendering process has a great influence on the performance of the cell.

Slitting Process

The function of the slitting machine is to slit the rolled pole pieces to the required width, which is the key process before winding process. Low-end slitting machines have low mechanical precision and simple tension control, which cannot be adapted to the slitting of ultra-thin film materials. With the improvement of users’ requirements for slitting efficiency and slitting quality, high-end slitting machines gradually have the function of wavy edge slitting, and have better tension control technology to optimize slitting speed and slitting quality. At present, the cutting speed of high-end slitting machines has reached 70 m/s.

Winding Process

Tension control is the core technology that affects the advanced level of the winding machine. During the whole winding process, in order to ensure the high consistency of the battery assembled from the cells, special attention should be paid to the tension control of the winding. The difference in tightness caused by tension fluctuations will cause uneven tensile deformation of the wound cells, resulting in layering of the cell material or S-shaped wrinkles, which will seriously affect the consistency of the product, and the surface of the diaphragm and pole piece will be uneven. The wrinkles will increase the internal resistance of the battery.

Stacking Process

The stacking machine is used for the production of soft-packed cells, which can achieve higher performance and safety than cylindrical and square cells. The stacking machine is to stack the positive electrode sheet, the separator, and the negative electrode sheet into small battery cells in sequence, and then stack the small battery cells in parallel to form a large battery cell. The advantages of the cells produced by the stacking process are: the internal resistance is low and the discharge platform is high; the force area between the cell pole pieces and the diaphragm is the same, and there is no obvious stress concentration point; the internal space the utilization is more sufficient; it is easier to complete large current discharge in a short time, and has good rate performance.

Electrolyte Filling

The role of the lithium battery electrolyte is to conduct ions between the positive and negative electrodes, acting as a medium for charging and discharging, just like the blood of the human body. How to fully and evenly infiltrate the electrolyte into the lithium battery has become an important issue. Therefore, the liquid injection process is a very important process, which directly affects the performance of the battery. Lithium battery injection can be divided into two steps: 1) Liquid injection: Inject the electrolyte into the battery; 2) Immersion Absorb the injected electrolyte into the cell, which is very time-consuming, which greatly increases the production cost of lithium-ion batteries.

Formation

The formation and aging process are the most critical links in the back-end process. The chemical composition of the lithium battery cell is to realize the initialization of the battery by charging and discharging, so that the active material of the cell is activated, which is a process of energy conversion. The principle of chemical composition and capacity of lithium batteries is relatively complicated, but it is also an important process that affects battery performance, because when Li+ is charged for the first time, Li+ is inserted into graphite for the first time, and an electrochemical reaction will occur in the battery.

Leak Detection

The electrolyte is generally prepared from high-purity organic solvents, electrolyte lithium salts, necessary additives and other raw materials under certain conditions and in a certain proportion, mainly including: EC,PC,DEC,DMC,EMC,LiPF6,PF5… If the closed test chamber is evacuated, if the electrolyte of the leaking battery will flow out with the gas, and then use a detector sensitive to the electrolyte to detect, then it can be judged whether the battery is leaking.

Packing

In the pack industry, the battery that is not assembled that can be used directly called cell, and the finished product that is connected to the PCM board and has the function of charge and discharge control is called the battery. The cell is the most important part of the pack. The main processes of Pack include welding, labeling, performance testing, size testing, leakage detecting, etc. Cylindrical cells, square case cells, and soft pack cells have the same packing process principle, but the production lines are quite different. Take a mobilephone battery pack as an example, the whole process is as:  

Overview of battery equipment processing

Lithium Battery Assembly, Lithium Ion Battery Assembly, Battery Cell Assembly, Battery Cell Assembly Process, Lithium-Ion Battery (LIB) Manufacturing Industry

The production process of lithium battery cells is divided into three stages: front, middle and back. The purpose of the front stage is to process the raw materials into pole pieces, and the core process is coating; the middle stage is to process the pole pieces into non-activated cells; The back process is detection and packaging, and the core process is formation and volume separation. According to the battery production and manufacturing process, lithium battery equipment is divided into front-end equipment, middle-stage equipment, and back-end equipment. The value of the front-end equipment accounts for about 40%, of which the value of the coating machine accounts for 75%, and the value of the roller press is greater than that of the slitting machine. Ternary materials have higher performance requirements for front-end equipment, and the value of front-end equipment will gradually increase. The value of the middle-stage equipment accounts for about 30%, of which the value of the winding machine accounts for 70%. At present, the market concentration of winding machine is relatively high, with CR3 reaching 60%-70%. The value of the back-end equipment accounts for about 30%, of which the chemical composition system accounts for 70% and the assembly accounts for 30%. After the production of the battery cell is completed, the pack process is carried out to form the finished product, which is what we call the battery. The main processes of the Pack process include welding, labeling, performance testing, size testing, liquid leakage detecting, etc. The value of pack equipment is smaller than that of cell equipment, accounting for about 5%~10% of cell equipment

Mixing process

Using a lithium battery vacuum mixer, with the action of a special solvent and a binder, the powdered positive and negative active materials are mixed, and after high-speed stirring, a slurry of positive and negative electrodes without bubbles is made.

Coating process

The coating machine is the core equipment of the previous process. The main purpose of coating is to uniformly coat the slurry with good stability, good viscosity and good fluidity on the surface of the positive and negative electrodes. The coating process must strictly ensure that no particles, sundries, dust, etc. are mixed into the pole piece. If the sundries are mixed in, it will cause a micro short circuit inside the battery, which will cause the battery to catch fire and explode in severe cases.

Calendering process

The function of Calendering is to compact the pole pieces and improve the energy density of the battery. After the pole piece is coated and dried in the previous process, the active material and the foil are easily peeled off. Therefore, it is necessary to roll the active material to enhance the bonding strength of the active material and the foil, The compaction density can increase the discharge capacity of the battery, reduce the internal resistance, reduce the polarization loss, prolong the cycle life of the battery, and improve the utilization rate of the lithium-ion battery. The calendering process has a great influence on the performance of the cell.

Slitting Process

The function of the slitting machine is to slit the rolled pole pieces to the required width, which is the key process before winding process. Low-end slitting machines have low mechanical precision and simple tension control, which cannot be adapted to the slitting of ultra-thin film materials. With the improvement of users’ requirements for slitting efficiency and slitting quality, high-end slitting machines gradually have the function of wavy edge slitting, and have better tension control technology to optimize slitting speed and slitting quality. At present, the cutting speed of high-end slitting machines has reached 70 m/s.

Winding Process

Tension control is the core technology that affects the advanced level of the winding machine. During the whole winding process, in order to ensure the high consistency of the battery assembled from the cells, special attention should be paid to the tension control of the winding. The difference in tightness caused by tension fluctuations will cause uneven tensile deformation of the wound cells, resulting in layering of the cell material or S-shaped wrinkles, which will seriously affect the consistency of the product, and the surface of the diaphragm and pole piece will be uneven. The wrinkles will increase the internal resistance of the battery.

Stacking Process

The stacking machine is used for the production of soft-packed cells, which can achieve higher performance and safety than cylindrical and square cells. The stacking machine is to stack the positive electrode sheet, the separator, and the negative electrode sheet into small battery cells in sequence, and then stack the small battery cells in parallel to form a large battery cell. The advantages of the cells produced by the stacking process are: the internal resistance is low and the discharge platform is high; the force area between the cell pole pieces and the diaphragm is the same, and there is no obvious stress concentration point; the internal space the utilization is more sufficient; it is easier to complete large current discharge in a short time, and has good rate performance.

Electrolyte Filling

The role of the lithium battery electrolyte is to conduct ions between the positive and negative electrodes, acting as a medium for charging and discharging, just like the blood of the human body. How to fully and evenly infiltrate the electrolyte into the lithium battery has become an important issue. Therefore, the liquid injection process is a very important process, which directly affects the performance of the battery. Lithium battery injection can be divided into two steps: 1) Liquid injection: Inject the electrolyte into the battery; 2) Immersion Absorb the injected electrolyte into the cell, which is very time-consuming, which greatly increases the production cost of lithium-ion batteries.

Formation

The formation and aging process are the most critical links in the back-end process. The chemical composition of the lithium battery cell is to realize the initialization of the battery by charging and discharging, so that the active material of the cell is activated, which is a process of energy conversion. The principle of chemical composition and capacity of lithium batteries is relatively complicated, but it is also an important process that affects battery performance, because when Li+ is charged for the first time, Li+ is inserted into graphite for the first time, and an electrochemical reaction will occur in the battery.

Leak Detection

The electrolyte is generally prepared from high-purity organic solvents, electrolyte lithium salts, necessary additives and other raw materials under certain conditions and in a certain proportion, mainly including: EC,PC,DEC,DMC,EMC,LiPF6,PF5… If the closed test chamber is evacuated, if the electrolyte of the leaking battery will flow out with the gas, and then use a detector sensitive to the electrolyte to detect, then it can be judged whether the battery is leaking.

Packing

In the pack industry, the battery that is not assembled that can be used directly called cell, and the finished product that is connected to the PCM board and has the function of charge and discharge control is called the battery. The cell is the most important part of the pack. The main processes of Pack include welding, labeling, performance testing, size testing, leakage detecting, etc. Cylindrical cells, square case cells, and soft pack cells have the same packing process principle, but the production lines are quite different. Take a mobilephone battery pack as an example, the whole process is as:  

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