Lithium ion battery formation process and lithium ion battery obtained by same

Abstract

The invention relates to a lithium ion battery formation process and a lithium ion battery obtained by the lithium ion battery formation process. The lithium ion battery formation process adopts a mode of combining segmented negative pressure and segmented current, and the formation process comprises three stages: in the first stage, the negative pressure is 20-60Kpa, and the lithium ion battery is charged to 5-15% SOC at a constant current of 0.05-1 C; in the second stage, the negative pressure is 80-90 Kpa, and the lithium ion battery is charged to 20%-30% SOC at a constant current of 0.1-0.3 C; in the third stage, the negative pressure is 20-40 Kpa, and the lithium ion battery is charged to a cut-off voltage at a constant current of 0.3-0.5 C. The formation process is beneficial to exhausting in the formation process, reducing the liquid loss, avoiding swelling of the battery cell and improving the formation interface; the process is simple and convenient to operate, short in formation time and convenient to produce, and meanwhile, the formation process adopts one-time full charge, so the interface side reaction of the electrode and the electrolyte is fully carried out, and thecapacity consistency and the self-discharge screening consistency are improved.

Description

technical field [0001] The invention belongs to the field of lithium ion batteries, and relates to a formation process of lithium ion batteries and the obtained lithium ion batteries. Background technique [0002] Benefiting from the rapid development of new energy vehicles, the power battery industry is ushering in a period of rapid growth. Lithium-ion batteries are ideal high-energy power sources in the future due to their superior characteristics such as high energy density, no memory effect, no pollution, and long cycle life. [0003] In the lithium-ion battery production process, the formation process is an extremely important step. This step is mainly to charge the battery cell for the first time to activate the lithium-ion battery; The negative electrode of the ion battery forms a layer of solid electrolyte interface (SEI) film, thereby preventing the further occurrence of side reactions and reducing the loss of lithium content in the lithium-ion battery, which is im...

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Problems solved by technology

[0004] At present, the lithium-ion battery formation process has problems such as long production cycle, high production cost, large amount of liquid loss, serious pollution of the liquid injection port, poor exhaust during the formation process, and poor interface between positive and negative electrodes, which seriously affect the production efficiency and power of lithium-ion batteries. performance

[0005] CN107706461A discloses a negative pressure formation method for a power lithium-ion battery. The negative pressure formation method is used to replace the open normal pressure formation method. Although it can facilitate the discharge of lithium-ion battery formation and gas production, the lithium-ion battery is in the peak period of formation and gas production. Using a high vacuum state will easily cause a large amount of electrolyte loss and affect the formation interface

[0006] CN108574115A discloses a nickel-cobalt lithium manganate lithium ion battery formation process, the method is formed under high temperature and high pressure with a small current and then a large current, which is beneficial to improve the uniformity of current density and the bulge of the formed cell during formation, but there is a formation Disadvantages such as poor exhaust, poor formation interface, high cost and complicated operation of high-pressure fixtures

[0007] CN108172919A discloses a ternary ion battery formation process and a ternary lithium ion battery and its preparation method. The method completes the formation of the lithium ion battery in a four-stage stepwise charging manner, but the formation time is long and the process is cumbersome. Disadvantages such as poor exhaust and poor formation interface

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