High-performance lithium battery and preparation method thereof

Abstract

The invention discloses a preparation method of a high-performance lithium battery, which comprises the following steps of placing a thermal adhesive diaphragm between a positive plate and a negativeplate, and preparing a battery cell, the thermal adhesive diaphragm being a diaphragm having an adhesion effect on an electrode material at a preset temperature or pressure; carrying out preheating and / or flat pressing treatment on the battery cell, wherein the temperature of the preheating treatment is greater than or equal to the softening temperature of the thermal adhesive material and is lessthan the melting temperature of the thermal adhesive material, the pressure intensity of the flat pressing treatment is greater than or equal to the yield limit of the hot viscous material; carryingout shaping treatment on the preheated and / or flattened battery cell; and carrying out post-treatment on the shaped battery cell to obtain the lithium ion battery. Correspondingly, the invention alsoprovides the lithium battery prepared by the method. By adopting the method, the energy consumption reduction, process condition simplification, equipment simplification and raw material simplification can be realized at the same time, and the battery is high in appearance size consistency and stability and high in performance consistency and stability.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a high-performance lithium battery and a preparation method thereof. Background technique [0002] At present, the manufacturing process of power lithium battery is as follows, beating-coating-sheet-making-winding (lamination)-shaping-encapsulation-liquid injection-aging-high temperature and high pressure formation-secondary packaging-division. Among them, formation is the key to the formation of SEI solid electrolyte membrane, which directly affects the electrical performance and safety performance of lithium batteries, and is the most critical process for battery performance. [0003] Existing chemical formation can be divided into hot-press chemical formation, high-temperature chemical formation and high-pressure chemical formation. At the same time of chemical formation, the interface impedance between the positive and negative electrodes and the separator is reduce...

AI Technical Summary

Problems solved by technology

[0004] 1. It needs long-term high-temperature heating and high energy consumption;

[0005] 2. The equipment is complex and expensive, and it needs to cooperate with setting fixtures. Manual operation is dangerous and has great safety hazards;

[0006] 3. High requirements on the electrolyte, need to add expensive high temperature resistant electrolyte;

[0007] 4. The performance of the battery varies greatly, because under high pressure, the heat is transferred from the fixture to the outer end of the battery cell and then to the inner layer. The gel layer of the outer diaphragm of the battery cell reaches the softening point earlier than the inner layer and deforms first.

This causes the outer diaphragm of the battery cell to be subjected to high temperature radiation for the longest time, and the deformation is the largest. The lithium ion passability is different due to the difference between the inner and outer layers, resulting in inconsistent electrical properties of the inner and outer layers of the battery cell, and the difference between the cells cannot be accurately controlled.

[0008] That is, the existing lithium battery manufacturing methods cannot simultaneously solve technical problems such as high energy consumption, complex and expensive equipment, particularly expensive electrolyte, and battery stability.

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