Battery slurry quality determine the Quality of the cells

Slurry 50% determine the quality cell

The quality of the battery is 70% related to the quality of the electrode sheets, and the quality of the electrode sheet is 70% related to the quality of the slurry.

Therefore, making the slurry well is equivalent to making 50% of the battery. This is the primary and core work of battery manufacturing.

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The purpose of mixing is to break various crystal particles and mix them evenly together while ensuring the preset viscosity and solid content.

1. Usually the mixing components include a stirring paddle and dispersion disk, as shown in the picture below

A good designed mixting part must make sure it will reach every where.

So, it will make the material particles smaller and evenly.

2. What is qualified cathode and anode slurry?

3. How to make qualified slurry?

First, prepare the (PVDF) glue solution. Use an ordinary mixing tank to first add a certain amount of solvent NMP, add the binder PVDF powder into it according to the designed solid content, and stir for 4 to 6 hours to obtain the PVDF glue. PVDF glue is a colorless and transparent liquid with a certain viscosity. The solid content can be controlled between 5% and 10% as needed. The prepared glue generally needs to be vacuumed and left to stand for more than 12 hours in order to eliminate bubbles generated during the stirring process. Then transfer a certain amount to the slurry preparation mixer through the sealed pipeline through the metering pump, add the conductive agent SP, and start the revolution (twist paddle) and rotation (dispersion plate) of the mixer at the same time, and the revolution speed is set to (25±5) r/min , the rotation speed is set to (500±50) r/min, and NMP spraying is assisted, so that the extremely light density SP can be fully mixed into the PVDF glue liquid, and the stirring time is 1 h.

Secondly, add the main positive material. In order to ensure that the main material and glue can be effectively and fully dispersed, it is generally added in steps, that is, first add 50% of the main material (such as NCM or LFP, etc.), set the revolution speed of (30±5) r/min and (300± 50) r/min rotation speed. After stirring for 5 minutes, add the remaining 50% of the main material, assist with appropriate NMP spraying, and maintain the above parameters for stirring for more than 1.5 hours. During the process, the stirring paddle is scraped as needed to prevent the powder adhering to the stirring paddle from being fully infiltrated due to the excessive wetting angle of the solid-liquid interface [2].

Finally, spray all the remaining NMP solvent into the mixer, increase the mixing speed, the rotation speed is (35±5) r/min, and the revolution speed is

(800±50) r/min, stir for 10 to 30 minutes, then increase the revolution speed to (1300±50) r/min and stir for 1.5 h to complete the slurry preparation. The prepared slurry needs to be transferred to a transfer tank for vacuum and defoaming treatment before use.

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