Preparation method of lithium secondary battery

A lithium secondary battery and battery technology, which is applied in the direction of secondary battery, electrolyte battery manufacturing, non-aqueous electrolyte battery, etc., can solve the problems of loss of charge and discharge efficiency, impact on battery rate performance, battery energy density, etc., to achieve improved stability The effect of high reliability, low production cost and good cycle performance

Inactive Publication Date: 2020-07-03
朱虎
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the prior art, in order to improve the cycle performance of lithium-ion batteries, it is mostly necessary to add film-forming additives. However, the addition of film-forming additives will first affect the energy density of the battery, and will also affect the rate performance of the battery. Loss of charge-discharge efficiency due to loss of lithium ions in the electrolyte during the membrane process

Method used

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  • Preparation method of lithium secondary battery
  • Preparation method of lithium secondary battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] 1) Place the positive pole and the negative pole in the first electrolytic solution, the solvent in the first electrolytic solution is EC and DMC, the electrolyte lithium salt is 1mol / L lithium hexafluorophosphate, and the additive is saturated lithium carbonate and saturated sulfurous acid Lithium, wherein there are solid lithium carbonate and lithium sulfite at the bottom of the first electrolyte;

[0032] 2) Charge to 2.90V with a constant current of 0.01C;

[0033] 3) Charge to 3.45V with a constant current of 0.02C;

[0034] 4) Charge to 3.75V with a constant current of 0.05C; then charge at a constant voltage at this voltage until the charging current is lower than 0.01C;

[0035] 5) Take out the positive pole and the negative pole, assemble them with the diaphragm to form a cell and put it into the battery case;

[0036] 6) Inject the second electrolytic solution and seal the seal. The solvent in the second electrolytic solution is ethylene carbonate, diethyl c...

Embodiment 2

[0041] 1) Place the positive pole and the negative pole in the first electrolytic solution, the solvent in the first electrolytic solution is EC and DMC, the electrolyte lithium salt is 1mol / L lithium hexafluorophosphate, and the additive is saturated lithium carbonate and saturated sulfurous acid Lithium, wherein there are solid lithium carbonate and lithium sulfite at the bottom of the first electrolyte;

[0042] 2) Charge to 2.95V with a constant current of 0.02C;

[0043] 3) Charge to 3.50V with a constant current of 0.05C;

[0044] 4) Use a constant current of 0.1C to charge to 3.80V; then charge at a constant voltage at this voltage until the charging current is lower than 0.01C;

[0045] 5) Take out the positive pole and the negative pole, assemble them with the diaphragm to form a cell and put it into the battery case;

[0046] 6) Inject the second electrolytic solution and seal the seal. The solvent in the second electrolytic solution is ethylene carbonate, diethyl ...

Embodiment 3

[0051] 1) Place the positive pole and the negative pole in the first electrolytic solution, the solvent in the first electrolytic solution is EC and DMC, the electrolyte lithium salt is 1mol / L lithium hexafluorophosphate, and the additive is saturated lithium carbonate and saturated sulfurous acid Lithium, wherein there are solid lithium carbonate and lithium sulfite at the bottom of the first electrolyte;

[0052] 2) Charge to 2.95V with a constant current of 0.02C;

[0053] 3) Charge to 3.45V with a constant current of 0.05C;

[0054] 4) Use a constant current of 0.1C to charge to 3.80V; then charge at a constant voltage at this voltage until the charging current is lower than 0.01C;

[0055] 5) Take out the positive pole and the negative pole, assemble them with the diaphragm to form a cell and put it into the battery case;

[0056] 6) Inject the second electrolytic solution and seal the seal. The solvent in the second electrolytic solution is ethylene carbonate, diethyl ...

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Abstract

The invention provides a preparation method of a lithium secondary battery. The lithium secondary battery comprises a positive electrode and a negative electrode; an active substance of the positive electrode is LiNi < 0.15 > Co < 0.35 > Mn < 0.5 > O < 2 >; an active substance of the negative electrode is carbon-coated silicon particles, the preparation method comprises the following steps: placing the positive electrode and the negative electrode in a first electrolyte for pre-formation, wherein the first electrolyte contains saturated lithium carbonate and saturated lithium sulfite as additives; obtaining the battery. According to the invention, an SEI film is formed on the surface of an electrode through a pre-formation process; the electrolyte used in the pre-formation is not the electrolyte of the finished battery; therefore, the influence of the additive on the later performance of the battery does not need to be considered, the selection source of the additive is wider, and lithium ions are not obtained from the battery electrolyte when the SEI film is formed, so that the irreversible capacity is not reduced, the obtained battery has better cycle performance, and the production cost is lower.

Description

technical field [0001] The invention relates to a preparation method of a lithium secondary battery, in particular to a formation method of a lithium secondary battery. Background technique [0002] Lithium-ion batteries are widely used in portable electronic devices because of their high energy density, and they will be used in fields such as hybrid electric vehicles and non-intermittent energy supply in the future. The additives and formation process of lithium-ion batteries have an important impact on the performance of lithium-ion batteries. In the prior art, in order to improve the cycle performance of lithium-ion batteries, it is mostly necessary to add film-forming additives. However, the addition of film-forming additives will first affect the energy density of the battery, and will also affect the rate performance of the battery. The loss of charge-discharge efficiency due to the loss of lithium ions in the electrolyte during the membrane process. Contents of the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/058H01M10/0567H01M10/0525
CPCH01M10/0525H01M10/0567H01M10/058H01M2300/0025Y02E60/10Y02P70/50
Inventor 朱虎
Owner 朱虎
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