Battery manufacturing - production process of NiMH No.7 batteries

Battery manufacturing - how to handle batteries

The battery is the smallest battery in the battery system. This is the basic structure of automotive power lithium-ion batteries. The battery is like a container for storing electrical energy. How much capacity it can store depends on how much active material is contained in the positive and negative electrodes. The design of the positive and negative plates should be adjusted according to different models. The gram capacity of the positive and negative electrode materials, the proportion of active materials, the thickness of the electrodes, the compaction density, etc. also have an important impact on their capacity.

Pulping of active materials. Mixing process

Stirring is to stir the active material into pulp through a vacuum mixer. This is the first step in battery processing. The quality control of this process will directly affect the quality of the battery and the qualified rate of the finished product. The process is complicated, and the raw material ratio, mixing steps, mixing time, etc. have high requirements.

So what we are mixing here is the active material of the battery.

In addition, during the mixing process, dust must be strictly controlled to prevent dust from affecting the consistency of the battery. The dust control level of the Ningde Times processing workshop is equivalent to the medical level.

The mixed paste will be coated in the copper foil coating process

This process is the last process, and the stirred slurry is evenly sprinkled on the bottom of the 4000-meter copper foil at a speed of 80 meters per minute. The copper foil before coating is only 6 microns thick, which can be described as thin as a silkworm's wing.

Coating is essential to ensure that the thickness and the electrode of the component are consistent, otherwise it will affect the consistency of the battery. The coating must also ensure that no particles, debris, and dust are mixed into the rod. Otherwise, the battery will discharge too quickly and even cause safety hazards.

The negative film on the copper foil is pressed up and down before cutting cold pressing and pre-cutting

In the rolling workshop, the plates with positive and negative data are connected to the rollers for rolling, so that the coated data is more dense, the energy density is improved, and the thickness consistency is guaranteed. On the other hand, dust and humidity are further controlled.

According to the size of the battery to be processed, the cold-pressed electrode sheet is cut to fully control the appearance of burrs (the burrs here can only be seen clearly under a microscope). The purpose of this is to prevent burrs from penetrating the gap and causing serious safety hazards.

Cut off the positive and negative ears on the battery pole, die-cut and parting

The ear die-cutting process is to use the die-cutting mechanism to make the ear into a conductive battery. We know that the battery is divided into positive and negative electrodes. The ear is separated from the metal conductor by the battery. The positive and negative ears of the battery are generally the contact points when the battery is charged and discharged.

The next step is to cut the battery with a cutting knife.

Complete the winding process of the prototype battery

Here, the positive, negative and isolation membrane of the battery are combined in a winding manner to form a bare battery. Advanced CCD visual inspection equipment can complete active inspection and active correction to ensure the good position of the battery pole.

CATL Ningde Battery Processing Workshop is one of the most active battery processing workshops in the world with the help of CCD visual inspection equipment.

Remove moisture and inject electrolyte baking and injection

Water is the enemy of the battery system. The process of battery baking is to make the inside of the battery meet the water standard and ensure that the battery has good function throughout its life cycle.

Liquid injection is to inject electrolyte into the cell. The electrolyte is like blood flowing in cells, and the exchange of energy is the exchange of charged ions. These charged ions are transported from the electrolyte to the other electrode, where they are charged and discharged. The injection amount of electrolyte is the key among the keys. If the injection amount of electrolyte is too large, it will cause the battery to heat up or even fail directly. If the injection amount is too small, it will affect the battery's cyclability.

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