Determination of Water Content Data of Lithium-ion Battery Raw Materials

Introduction

Lithium batteries play an indispensable role in our lives. Our daily handsets, laptops, household appliances, etc. The demand for lithium-ion batteries such as aircraft, hybrid vehicles, and electric vehicles as vehicles has also increased significantly. In the process of manufacturing lithium-ion batteries, there are many things that must be strictly controlled. One is dust, the other is metal particles, and the third is water.

Influence of Water on lithium battery and Current Market Situation

2.1 What are the adverse effects of water on lithium-ion batteries?

The main manifestations are the small battery capacity, the shorter discharge time, the increase in internal resistance, the attenuation of the cycle capacity, and the expansion of the battery. Therefore, in the process of making lithium-ion batteries, It is necessary to strictly control the humidity of the environment and the water content of the positive and negative electrode materials, diaphragm and electrolyte.

2.2 Current status of water control methods for lithium-ion batteries?

At present, the most commonly used technical methods for the determination of water content on the market are the heating weightlessness method and the Kalfeixiu method. Due to the extremely low water content of the samples measured by the lithium battery industry, the accuracy of the water measurement instrument for the heating and loss method is simply not reached. This method is directly excluded.

III. Analysis and methodology

3.1 Instruments

AKF-BT2015C Lithium battery Cartesian hydrometer

3.2 Technical parameters and characteristics

Features:

1. Kaiser top empty sample bottle heating technology, effectively avoid heating furnace and reaction cup pollution;

2. The original sample bottle connector, so that the carrier gas can enter the inside of the sample bottle without piercing the sample bottle cushion, is well sealed, and can be disassembled while reducing the cushion consumables;

3. Accurate flow control design, carrying gas consumption is only one-tenth of the same type of imported pipe heating furnace;

4. High-power heat sink design, quickly cooling sample bottles, improve working efficiency;

5.7 "High-resolution color touch screen interface, multi-parameter display, intuitive and concise; First key determination, the operation is extremely simple;

6. Non-dead volume design of anti-condensation insulation pipeline to ensure that there is no residue in the water partition pipe wall system after volatilization;

7. Heating temperature up to 300 °, 0-100ml gas flow freely adjusted, to meet the needs of most solid raw material moisture determination;

8. Automatic constant current polarization detection, no need to set the end point manually, high detection accuracy, water measurement resolution of 0.1 UG;

9. One key start, simple operation, stable and reliable, low failure, long service life;

3.3 Principles of analysis

The sample is loaded with a special sealed sample vial of the Cartesian furnace, sealed with an empty bottle connector, and then enters the heating tank. The moisture in the sample(and possibly other volatile solvents) is completely released in the form of vapor. By drying the carrier gas(such as dry air or nitrogen), it is transferred from the top empty bottle to the KF titration cup via a heating pipe, and then the Kalfeieu hydrometer is tested and the measurement data is displayed.

3.4 Detection methods

1. Inject the electrolyte into the cathode Chamber of the electrolytic cell and the electrolytic electrode, the liquid level to the lower scale line, add a small amount of water and electrolysis to balance.

2. Connect the gas source to the Cartesian furnace, load the dry sample bottle into the heating tank, set the temperature to 250 °C, adjust the flow rate to 50mL/min, and sweep the sample bottle and pipeline for possible moisture and wait for balance again.

3. Move the sample bottle to the cooling tank and take it out after cooling. Use the electronic balance to take about 0.5 ~ 3G samples and place them in the sample bottle. Then click on the hydrometer to start the measurement. At the same time, load the sample bottle into the heating tank.

4. Enter the weight of the sample and wait until the final measurement results are displayed.

Data and conclusions

Concluding remarks:

Through the experimental method, the moisture content of the raw material of the lithium ion battery can be accurately measured, and the accuracy and repeatability of the detection result reach the level of the imported similar products. The AKF Coulometric Karl Fischer Moisture Analyzer and the KH-1 Cartesian Furnace Headspace Sampler can be used to automatically deduct drift, and it is easy to operate. It can accurately and reliably measure the water content of lithium batteries and raw materials.

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