High-temperature-resistant integrated electrode for lithium ion battery and preparation method of high-temperature-resistant integrated electrode

Abstract

The invention discloses a high-temperature-resistant integrated electrode for a lithium ion battery and a preparation method of the high-temperature-resistant integrated electrode. The preparation method comprises the following steps of preparing a battery active material into a battery pole piece by using a PI adhesive, and covering the surface of the battery pole piece with a nanofiber membrane or a polymer / inorganic material nanofiber composite membrane through adopting an electrostatic spinning method to obtain the high-temperature-resistant integrated electrode. In the high-temperature-resistant integrated electrode, the PI adhesive has relatively good structural stability under a high-temperature condition, so that the battery pole piece is kept stable in structure under the high-temperature condition and plays a role in supporting thermal shrinkage of the nanofiber membrane, a nanofiber layer provides insulativity, high-temperature dimensional stability and high liquid retention, short circuit in the battery is prevented, and thermal runaway of the assembled battery caused by internal short circuit due to shrinkage of the high-temperature diaphragm is prevented, so that the thermal safety characteristic of the battery is improved. The technical process is simple and easy to implement, the safety of the battery assembled by using the pole piece is obviously improved, and the integrated pole piece has a good application prospect.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery electrode pole pieces and preparation methods thereof, in particular to a high-temperature-resistant integrated electrode for lithium-ion batteries and a preparation method thereof. Background technique [0002] Lithium-ion batteries have been widely used in small electronic devices such as PCs, mobile phones, and AV equipment due to their environmental friendliness and long cycle life. With its application in electric vehicles, lithium-ion batteries have begun to develop in the direction of large capacity and high specific energy, and the safety issues that follow have become increasingly prominent. Therefore, designing lithium-ion batteries with high energy density and high safety become a top priority. [0003] Lithium-ion batteries are composed of positive electrodes, diaphragms, electrolytes, and negative electrodes. The positive and negative electrodes are composed of powdery ac...

AI Technical Summary

Problems solved by technology

[0004] However, the existing adhesives have poor temperature resistance, which makes the connection between positive and negative active materials, conductive agents and electrode current collectors weak under high temperature conditions. Poor structural stability, resulting in attenuation of battery capacity

In addition, the existing adhesives are prone to degradation at high temperatures, which can easily lead to safety issues such as battery failure and even loss of control

[0005] Under the condition of high temperature, the conventional polyolefin diaphragm will also cause local internal short circuit of the battery due to thermal shrinkage at high temperature, which will lead to battery runaway. In order to solve these problems, the patent CN 104681764 A directly spins a layer of nanofiber membrane on the surface of the ceramic diaphragm to prepare A composite lithium-ion battery diaphragm, in which the nanofiber layer can reinforce and bind ceramic particles to prevent falling off, and can also be used as a soft buffer layer to improve the contact between the diaphragm and the electrode surface. However, in this method, the fiber film is directly sprayed on the surface of the ceramic layer. Only by physical adsorption, the adhesion is poor, and it is still difficult to change the shortcoming of the temperature difference of the polyolefin base film

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