What is the packaging process of the soft pack battery?

In the aluminum-plastic film forming process of the soft-pack battery packaging process, the soft-pack batteries can be designed into different sizes according to the needs of customers. When the external dimensions are designed, the corresponding mold must be opened to form the aluminum-plastic film. The forming process is also called punching. As the name suggests, it uses a forming mold to punch a pit that can hold a core in the aluminum-plastic film under heating. After the aluminum-plastic film is punched and cut into shape, it is generally called a Pocket bag. Generally, when the battery core is thin, choose to punch a single pit, when the battery core is thick, choose to punch a double pit, because too much deformation on one side will break through the deformation limit of the aluminum-plastic film and cause rupture. Sometimes, according to the design requirements, a small hole is punched in the position of the air bag to expand the volume of the air bag. Top-side sealing process, top-side sealing process is the first packaging process of soft-packed lithium-ion batteries. The top side seal actually includes two processes, the top seal and the side seal. First put the wound core into the punched pit, and then fold the packaging film in half along the dotted line, as shown in the figure below. The following picture shows several positions to be packaged after the aluminum-plastic film is loaded into the core, including the top sealing area, side sealing area, one sealing area and the second sealing area. The analysis is performed separately below. After the core is placed in the pit, the entire aluminum plastic film can be placed in the fixture, and the top and side sealing are performed in the top side sealing machine. The top-side sealing machine is like this: this type of top-side sealing machine has four clamps, the left station is for top sealing, and the right station is for side sealing. The two pieces of yellow metal are the upper head, and there is a lower head underneath. The two heads have a certain temperature (usually around 180°C) when they are packaged, and they are pressed on the aluminum plastic film when they are closed. The PP layer of the film is melted and then bonded together, and the package is OK. It is still important to say that the top seal is to seal the tabs. The tabs are made of metal (aluminum anode and nickel cathode). How to package it with PP? This is done by a small part of the lug on the lug. I am not very clear about the specific structure of the tabular glue. I hope someone who knows how to do it will add it. I only know that it also has the cost of PP, which means it can melt and bond when heated. The package at the tab position is shown in the circled part in the figure below. During packaging, the PP in the tab glue and the PP layer of the aluminum-plastic film are melted and bonded to form an effective packaging structure. In the process of liquid injection and pre-sealing, after the soft-packed cell is sealed on the top side, X-ray is required to check the parallelism of the core, and then go into the drying room to remove moisture. After a certain period of time in the drying room, it enters the liquid injection and pre-sealing process. Through the above analysis, we know that after the cell is sealed on the top side, there is only one opening on the air bag side, and this opening is used for liquid injection. After the liquid injection is completed, the pre-sealing of the side of the air bag should be performed immediately, which is also called one. After a package is completed, the core is theoretically completely isolated from the external environment. The packaging principle of a letter is the same as that of the top side seal, so I won't go into details here. In the process of standing, forming, and jig shaping, after the liquid injection and one seal are completed, the battery cell must first be allowed to stand. Depending on the process, it will be divided into high temperature standing and normal temperature standing. The purpose of standing is to make the injection Electrolyte fully soaks the pole piece. Then the batteries can be used to make them. It is a forming cabinet with soft-packed batteries, which is actually a charging and discharging device. I haven't found a picture of the charged core for a long time. Think about the picture of the battery sandwiched on it and it's OK. The chemical achievement is the first charging of the battery, but it will not be charged to the highest voltage used, and the charging current is also very small. The purpose of chemical conversion is to form a stable SEI film on the electrode surface, which is equivalent to a process of activating the cell. In this process, a certain amount of gas will appear, which is why the aluminum plastic film needs to reserve an air bag. In some factories, the process will use fixture formation, that is, the cell is clamped in the fixture (sometimes it is simple to use a glass plate, and then a steel clamp is used), and then the gas will be fully squeezed to the side of the cabinet. The electrode interface after chemical formation is also better when it is removed in the bag. After formation, some cells, especially thick cells, may undergo certain deformation due to large internal stress. Therefore, some factories will set up a fixture shaping process after the formation, which is also called fixture baking. In the second sealing process, I just said that gas will appear during the formation process, so we have to extract the gas and then perform the second encapsulation. Some companies here have two processes: exhaust and second sealing, and the latter process of cutting the air bag. Here I will call them the second sealing in general. In the second seal, the air bag is first pierced by a guillotine and a vacuum is drawn at the same time, so that the gas and a small part of the electrolyte in the air bag will be drawn out. Then immediately the second sealing head is encapsulated in the second sealing area to ensure the air tightness of the cell. Finally, cut off the air bag of the encapsulated cell, and a soft-packed cell is basically formed. The second seal is the last packaging process of the lithium battery, and its principle is still the same as the previous thermal packaging, so I won't repeat it. Disclaimer: The articles published on this website are all from the Internet. If there is any infringement, please contact to delete it. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Analysis of the correct charging method for lithium batteries