When it comes to batteries, many people know its basic structure, such as positive and negative tabs, positive and negative electrodes, diaphragm, electrolyte, etc., but they know very little about how the battery is made. Below we will introduce step by step according to the basic manufacturing process of producing mobile phone batteries.

1.Materials 

The main components of the positive electrode material of the battery are lithium, a binder, and a conductive agent; while the main components of the negative electrode material are carbon and a binder. This process is to stir the materials of the positive and negative electrodes at high speed into a slurry, which is applied to the aluminum foil and copper foil in the subsequent process.

2.Coating

The function of coating is to apply the positive and negative electrode slurry to the aluminum foil and copper foil, wherein the positive electrode uses aluminum foil, and the negative electrode uses copper foil.

3.Pressing

Why pressing? One is that the electrode slurry after being coated on the foil is relatively loose, which is prone to material drop; the other is that in order to increase the energy density of lithium-ion batteries, the volume of the battery is strictly controlled, and controlling the volume of the battery is naturally important for the control of the thickness of the battery.At present, the thickness control of the electrode sheet of the mobile phone battery is generally between 0.08 and 0.15 mm.

4.Cutting

The next step is to cut the large roll of positive and negative electrodes into small rolls of positive and negative electrodes, which are cut according to the width of the positive and negative electrodes designed for the battery model, and the width of the negative electrode is wider than that of the positive electrode. . The reason why the negative electrode is wider than the positive electrode is that if the diaphragm on the edge of the negative electrode is damaged, it will not cause a short circuit due to the contact between the positive and negative electrodes.

5.(Film production) Winding/Lamination

Here, let’s first talk about the design process of the battery tabs. The battery tabs are divided into single-pole tabs and multi-pole tabs.Single-pole tab means that the positive and negative poles have one tab each, while multi-pole tab means that the number of positive and negative poles is more than one.

The production process of the battery with multiple tabs is separate. First, the tabs are welded to the positive and negative plates, and then transferred to the subsequent process. The follow-up process is winding and lamination. Winding and lamination are just two different processes of winding and stacking the positive electrode foil, negative electrode foil, and flim separator into a battery cell.

6.Encapsulation/Assembly

Encapsulation and assembly are two different battery processes. Encapsulation is used for soft packaging batteries, and assembly is used for hard shell batteries. soft packaging batteries use aluminum-plastic film, and hard shell batteries use aluminum shells. Today's smart phones are generally designed with non-removable batteries, so there will be more batteries in soft packaging.

Encapsulation is to put the battery pole core material into the aluminum-plastic film, and then use high temperature to press the side and top of the aluminum-plastic film. In order to ensure the sealing effect, only one hole is reserved for injecting electrolyte. For assembly, after the battery is put into the aluminum case, the positive and negative tabs are welded to the aluminum cover plate, and then the cover plate and the aluminum case are welded together by laser welding. There is a liquid injection hole on the cover plate for electrolytes injection.

7.Baking

In fact, baking can also be classified as a liquid injection process, and the function of baking is to remove moisture. The unfinished battery will absorb the moisture in the air after long-term contact with the air, because the moisture remaining inside the battery cell is prone to chemical reactions and causing the battery to bulge.

8.Liquid Injection

After baking, the electrolyte can be injected. In the process of liquid injection, soft-pack batteries and hard-shell batteries are different. The hard-shell battery will be injected with a little electrolyte first, and then charged for the first time for a short time. After charging, the second injection will be performed, and the injection hole will be sealed with steel balls after the second injection. The soft-pack battery is different. The soft-pack battery is injected once, and then the side of the airbag is also sealed with high temperature.

9.Charge and discharge

The purpose of charging and discharging the battery is to form a passivation layer covering the surface of the negative electrode material. This passivation film is called: solid electrolyte interface film, the role of this film is to become a conductor of lithium ions.

10.Testing and packaging

The battery will be transferred to the testing process, the appearance and weight of the battery will be inspected, and then various testing processes will be carried out.After these processes are completed, a complete mobile phone battery is produced.

About Oriwhiz

Oriwhiz company is a professional mobile phone lcd screen manufacturer,our company is located in Shenzhen China.We have clients all over the world and we promise to do our best to better service our valued customer..We are one of the best seller of mobile phone parts,phone LCD parts,phone LCD wholesale.We can supply most of cell phone spare parts such as Back battery cover,iPhone charging flex,iPhone battery,iPhone front camera back camera,Speaker,Power flex,lcd touch screen, etc.We can also supply cell phone accessories and other mobile phone electronic products.In addition to iPhone related products,we have mobile phone parts for Samsung, Xiaomi, Huawei, Infinix, Oppo, Vivo, Meizu, etc.If you have any question and for cooperation,please don’t hesitate to contact us.

Article reference:Li-ion cell manufacturing: A look at processes and equipment