A kind of preparation method of lithium ion battery

A lithium-ion battery and electrolyte technology, which is applied in the manufacture of electrolyte batteries, secondary batteries, non-aqueous electrolyte batteries, etc., can solve problems such as increasing initial discharge capacity, affecting battery rate performance, and battery volume expansion, so as to reduce volume Expansion rate, improvement of battery cycle performance, and effects of stabilizing battery potential

Active Publication Date: 2020-06-16
金明信(北京)科技有限公司
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Problems solved by technology

Ethylene sulfate is a commonly used additive for lithium-ion battery electrolytes. Its function is to inhibit the decline in the initial capacity of the battery, increase the initial discharge capacity, reduce the expansion of the battery after high temperature storage, and improve the charge and discharge performance and cycle times of the battery. However, sulfuric acid The addition of ethylene ester will lead to an increase in the internal resistance of the battery, thereby affecting the rate performance of the battery. Further, the inventors found that the formation in an atmosphere containing carbon dioxide can further reduce the internal resistance, but as the number of cycles increases, the battery The volume of the battery will still expand to a large extent, so it is necessary to provide a method to improve the charge and discharge performance and cycle times of the battery

Method used

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  • A kind of preparation method of lithium ion battery

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Effect test

Embodiment 1

[0028] In the electrolyte in this embodiment, ethylene sulfate accounts for 0.5% of the total volume of the electrolyte, and the concentration of sodium hexafluorophosphate in the electrolyte is 0.001mol / L;

[0029] 1), inject electrolyte;

[0030] 2), move the lithium-ion battery after liquid injection into the glove box and charge it to 3.6V with a constant current of 0.02C, wherein the atmosphere in the glove box is nitrogen containing 10% by volume of carbon dioxide;

[0031] 3) Charge with a constant voltage of 3.6V until the charging current drops below 0.01C;

[0032] 4), between 3.55-3.65V, use a current of 0.02C to perform constant current charge and discharge cycles for 3 times;

[0033] 5), adjust the atmosphere in the glove box, reduce the volume percentage of carbon dioxide in the nitrogen to 3%;

[0034] 6), between 3.55-3.65V, use a current of 0.02C to perform constant current charge and discharge cycles for 3 times;

[0035] 7) Charge with a constant current...

Embodiment 2

[0038] In the electrolyte in this embodiment, ethylene sulfate accounts for 3% of the total volume of the electrolyte, and the concentration of sodium hexafluorophosphate in the electrolyte is 0.02mol / L;

[0039] 1), inject electrolyte;

[0040] 2), move the lithium-ion battery after liquid injection into the glove box and charge it to 3.6V with a constant current of 0.02C, wherein the atmosphere in the glove box is nitrogen containing 15% by volume of carbon dioxide;

[0041] 3) Charge with a constant voltage of 3.6V until the charging current drops below 0.01C;

[0042] 4), between 3.55-3.65V, use a current of 0.02C to perform constant current charge and discharge cycles for 3 times;

[0043] 5), adjust the atmosphere in the glove box, reduce the volume percentage of carbon dioxide in the nitrogen to 2%;

[0044] 6), between 3.55-3.65V, use a current of 0.02C to perform constant current charge and discharge cycles for 3 times;

[0045] 7) Charge with a constant current of...

Embodiment 3

[0048] In the electrolyte in this embodiment, ethylene sulfate accounts for 1% of the total volume of the electrolyte, and the concentration of sodium hexafluorophosphate in the electrolyte is 0.01mol / L;

[0049] 1), inject electrolyte;

[0050] 2), move the lithium-ion battery after liquid injection into the glove box and charge it to 3.6V with a constant current of 0.02C, wherein the atmosphere in the glove box is nitrogen containing 10% by volume of carbon dioxide;

[0051] 3) Charge with a constant voltage of 3.6V until the charging current drops below 0.01C;

[0052] 4), between 3.58-3.62V, use a current of 0.02C to perform constant current charge and discharge cycles for 3 times;

[0053] 5), adjust the atmosphere in the glove box, the volume percentage of carbon dioxide in the nitrogen is reduced to 0;

[0054] 6), between 3.58-3.62V, use a current of 0.02C to perform constant current charge and discharge cycles for 3 times;

[0055] 7) Charge with a constant current...

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Abstract

The invention provides a preparation method of a lithium-ion battery. The electrolyte of the lithium-ion battery includes ethylene sulfate and sodium hexafluorophosphate as additives, wherein ethylene sulfate accounts for 0.5-3% of the total volume of the electrolyte. %, the concentration of sodium hexafluorophosphate in the electrolyte is 0.001-0.02mol / L, wherein the formation method includes the first step of formation under the atmosphere of high concentration carbon dioxide, and under the atmosphere of low concentration or zero concentration carbon dioxide In the second step of chemical formation, a stable SEI film is formed by the method of the present invention, which avoids an increase in internal resistance and reduces the volume expansion rate of the battery after cycling, especially in a high-temperature environment.

Description

technical field [0001] The invention relates to the technical field of flexible packaging lithium ion batteries, in particular to a preparation method of lithium ion batteries. Background technique [0002] The new policy of new energy vehicles has released a signal to promote battery performance and increase energy density. With the continuous improvement of the subsidy threshold, lithium-ion batteries, as a means of lightweight and high-energy batteries, occupy a relatively high proportion of the market. Lithium-ion batteries can help more battery companies improve energy density and product competitiveness. Ethylene sulfate is a commonly used additive for lithium-ion battery electrolytes. Its function is to inhibit the decline in the initial capacity of the battery, increase the initial discharge capacity, reduce the expansion of the battery after high temperature storage, and improve the charge and discharge performance and cycle times of the battery. However, sulfuric ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/0567H01M10/0525H01M10/058H01M10/44H01M10/42
CPCY02E60/10Y02P70/50
Inventor 李壮
Owner 金明信(北京)科技有限公司
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