Cylindrical lithium ion battery capable of automatically pre-lithiating and preparation method thereof

Abstract

The invention discloses a cylindrical lithium ion battery capable of automatically pre-lithiating and a preparation method thereof. The battery comprises a battery shell, a battery cap, a battery celland electrolyte, the battery cell and the electrolyte are arranged in the battery shell, the battery cell is formed by winding a positive plate, a negative plate and a diaphragm arranged between thepositive plate and the negative plate at intervals, the negative plate is connected with a negative lug, and the negative lug is connected to the bottom of the battery shell; a central hole is formedin the center of the battery cell, and metal lithium or lithium-containing alloy is added to the bottom of the battery shell through the central hole; and the metal lithium or the lithium-containing alloy is electrically communicated with the negative lug. The invention provides an external lithium source. An SEI film (a solid electrolyte interface film) can be formed on the surface of the negative electrode after liquid injection of the battery, the problem of too low initial efficiency of the negative electrode is solved, the battery capacity is improved, the negative electrode can be further embedded into the negative electrode, the negative electrode active lithium reserve is increased, and the capacity loss caused by too fast negative electrode active lithium consumption in the long-term storage or circulation process of the battery is prevented.

Description

technical field [0001] The invention relates to the technical field of lithium batteries, in particular to a cylindrical lithium ion battery capable of automatic pre-lithiation and a preparation method thereof. Background technique [0002] With the development of lithium-ion battery technology, more and more devices use lithium-ion batteries as power sources, freed from the shackles of power cords. However, whether it is electric vehicles, household appliances or outdoor portable devices, power supplies with high energy density, long battery life and long service life are required, and negative electrode pre-lithiation is the key technology to solve these problems. However, most of the current pre-lithiation methods are complicated in process and difficult to implement, which not only greatly increases the cost, but also has low production efficiency, which affects the use. [0003] In Chinese patent application 201780017008.0, compositions, systems, and methods for making...

AI Technical Summary

Problems solved by technology

This method uses chemical or electrochemical pre-lithiation to pre-lithiate the negative electrode, and adds an additional step of pre-lithiation post-treatment process. This method is too complicated and greatly increases the cost of the battery.

[0004] In the Chinese patent application 201610808809.6, a pre-lithiated negative electrode, a secondary battery including it, and their manufacturing method are disclosed. The method first coats an active material layer on the negative electrode current collector, and then coats the negative electrode active material with a layer buffer layer, and finally coat a lithium metal layer on the outside of the buffer layer to achieve pre-lithiation of the negative electrode. This method is also too complicated, too expensive, and difficult to implement.

This method can place multiple batteries in the electrolyte at the same time for pre-lithiation, but due to the need for external circuit charging, the efficiency is low, and a large amount of electrolyte will be wasted at the same time, making it difficult to perform in large quantities.

In addition, due to the large amount of electrolyte remaining in the battery cell, post-treatment is required after pre-lithiation to carry out processes such as welding into the shell, which greatly increases the cost

[0006] Chinese patent application 201510970781.1 discloses a new type of lithium-ion battery and its preparation method. The method forms a third electrode by riveting or coating, bonding, and drying a film on the inner surface of the metal shell of the battery. The third electrode is Composite electrodes composed of metal lithium or lithium intercalation compounds, adhesives, conductive agents, and auxiliary functional components can supplement lithium by forming a charge-discharge circuit between the third electrode and the negative electrode at different stages of the battery. This method can be flexibly controlled The amount of lithium replenishment at each stage, but because the third electrode needs to be attached to the inside of the battery case, it will occupy the available space of the battery cell, resulting in a decrease in battery capacity. At the same time, the preparation process of the third electrode is difficult and difficult to implement

Images