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...

Examples

Embodiment 1

[0048] In this embodiment, the lithium-ion battery adopts a small soft-pack battery of high-nickel ternary material; the change curve of its gas production with SOC is as follows figure 1 shown; the test method of the gas production curve is: drainage method; by figure 1 It can be seen that the formation and gas production can be divided into the following three stages:

[0049] Among them, the first stage: when the battery is below 5% SOC, the gas formation rate is faster;

[0050] In the second stage, when the battery is at 5%-15% SOC, the gas formation rate slows down;

[0051] In the third stage, when the battery reaches more than 20% SOC, the formation and gas production gradually stop, and the SEI film is basically formed.

[0052] In this embodiment, the chemical conversion process includes:

[0053] Stand still: After the liquid injection, the high-nickel ternary material small pouch battery is allowed to stand at 45°C and normal pressure for 24 hours; and

[0054]...

Embodiment 2

[0061] The difference between this embodiment and Embodiment 1 is that in the first stage, the negative pressure is -60KPa, and the battery is charged at a constant current of 0.1C to 15% SOC; and

[0062] In the second stage, the negative pressure is -80KPa, and it is charged to 20% SOC at a constant current of 0.12C; and

[0063] In the third stage, the negative pressure is -40KPa, and it is charged at a constant current of 0.32C to a cut-off voltage of 4.2V;

[0064] Other parameters and conditions are exactly the same as in Example 1.

Embodiment 3

[0066] The difference between this embodiment and Embodiment 1 is that in the first stage, the negative pressure is -20KPa, and the battery is charged to 5% SOC at a constant current of 0.05C; and

[0067] In the second stage, the negative pressure is -90KPa, and it is charged to 30% SOC at a constant current of 0.3C; and

[0068] In the third stage, the negative pressure is -20KPa, and it is charged at a constant current of 0.5C to a cut-off voltage of 4.2V;

[0069] Other parameters and conditions are exactly the same as in Example 1.

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...

Examples

Embodiment 1

[0048] In this embodiment, the lithium-ion battery adopts a small soft-pack battery of high-nickel ternary material; the change curve of its gas production with SOC is as follows figure 1 shown; the test method of the gas production curve is: drainage method; by figure 1 It can be seen that the formation and gas production can be divided into the following three stages:

[0049] Among them, the first stage: when the battery is below 5% SOC, the gas formation rate is faster;

[0050] In the second stage, when the battery is at 5%-15% SOC, the gas formation rate slows down;

[0051] In the third stage, when the battery reaches more than 20% SOC, the formation and gas production gradually stop, and the SEI film is basically formed.

[0052] In this embodiment, the chemical conversion process includes:

[0053] Stand still: After the liquid injection, the high-nickel ternary material small pouch battery is allowed to stand at 45°C and normal pressure for 24 hours; and

[0054]...

Embodiment 2

[0061] The difference between this embodiment and Embodiment 1 is that in the first stage, the negative pressure is -60KPa, and the battery is charged at a constant current of 0.1C to 15% SOC; and

[0062] In the second stage, the negative pressure is -80KPa, and it is charged to 20% SOC at a constant current of 0.12C; and

[0063] In the third stage, the negative pressure is -40KPa, and it is charged at a constant current of 0.32C to a cut-off voltage of 4.2V;

[0064] Other parameters and conditions are exactly the same as in Example 1.

Embodiment 3

[0066] The difference between this embodiment and Embodiment 1 is that in the first stage, the negative pressure is -20KPa, and the battery is charged to 5% SOC at a constant current of 0.05C; and

[0067] In the second stage, the negative pressure is -90KPa, and it is charged to 30% SOC at a constant current of 0.3C; and

[0068] In the third stage, the negative pressure is -20KPa, and it is charged at a constant current of 0.5C to a cut-off voltage of 4.2V;

[0069] Other parameters and conditions are exactly the same as in Example 1.

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