Lithium ion secondary battery and electrolyte solution thereof

Abstract

The invention discloses a lithium ion secondary battery and an electrolyte solution thereof. The electrolyte solution is composed of lithium salt, a non-aqueous organic solvent and an additive, wherein the additive comprises one of or two of N-olefin imide and N-alkynes imide. Compared with the prior art, the additive in the electrolyte of the lithium ion secondary battery can effectively improve a positive / electrolyte interface to restrain the oxygenolysis of the electrolyte on the positive surface, so that the storage performance of the lithium ion secondary battery at a high temperature is remarkably improved.

Description

technical field

[0001] The invention relates to a lithium-ion secondary battery, in particular to a lithium-ion secondary battery electrolyte capable of improving the high-temperature storage performance of the battery. Background technique

[0002] Lithium-ion secondary batteries have the advantages of high operating voltage, long life, and fast charging speed. However, with the continuous development of technology, people require lithium-ion secondary batteries to have higher energy density. Studies have found that increasing the working voltage of lithium-ion secondary batteries is one of the effective ways to increase their energy density. However, with the high voltage of lithium-ion secondary batteries, the oxidation and decomposition of the electrolyte at the positive electrode intensify, and the batteries are stored at high temperatures. Sometimes there will be flatulence problems due to the oxidative decomposition of the electrolyte.

[0003] Generally, in a charge...

Examples

Embodiment 1

[0022] Preparation of lithium-ion secondary battery cathode sheet: Lithium cobalt oxide, conductive agent SuperP, and binder PVDF are mixed uniformly at a mass ratio of 96:2.0:2.0 to make a lithium-ion secondary battery cathode slurry with a certain viscosity, and coated On the current collector aluminum foil, the coating amount is 0.0194g / cm 2 , after drying at 85°C, cold pressing; then trimming, cutting, and slitting, drying at 85°C for 4 hours under vacuum conditions, welding the tabs, and making a lithium-ion secondary battery positive electrode that meets the requirements piece.

[0023] Preparation of lithium-ion secondary battery negative electrode sheet: graphite, conductive agent SuperP, thickener CMC, and adhesive SBR are prepared into a slurry at a mass ratio of 96.5:1.0:1.0:1.5, coated on the current collector copper foil and Dried at 85°C, the coating weight is 0.0089g / cm 2 ; After trimming, cutting, and slitting, dry at 110° C. for 4 hours under vacuum conditio...

Embodiment 2

[0027] The lithium ion secondary battery was prepared with reference to the method of Example 1, except that when preparing the lithium ion secondary battery electrolyte, the additives were: 1,3-propane sultone (PS) with a mass percentage content of 3% and mass The percentage content is 1% N-allyl succinimide.

Embodiment 3

[0029] The lithium ion secondary battery was prepared with reference to the method of Example 1, except that when preparing the electrolyte solution for the lithium ion secondary battery, the additive was: N-allyl succinimide with a mass percent content of 1%.

technical field

[0001] The invention relates to a lithium-ion secondary battery, in particular to a lithium-ion secondary battery electrolyte capable of improving the high-temperature storage performance of the battery. Background technique

[0002] Lithium-ion secondary batteries have the advantages of high operating voltage, long life, and fast charging speed. However, with the continuous development of technology, people require lithium-ion secondary batteries to have higher energy density. Studies have found that increasing the working voltage of lithium-ion secondary batteries is one of the effective ways to increase their energy density. However, with the high voltage of lithium-ion secondary batteries, the oxidation and decomposition of the electrolyte at the positive electrode intensify, and the batteries are stored at high temperatures. Sometimes there will be flatulence problems due to the oxidative decomposition of the electrolyte.

[0003] Generally, in a charge...

Examples

Embodiment 1

[0022] Preparation of lithium-ion secondary battery cathode sheet: Lithium cobalt oxide, conductive agent SuperP, and binder PVDF are mixed uniformly at a mass ratio of 96:2.0:2.0 to make a lithium-ion secondary battery cathode slurry with a certain viscosity, and coated On the current collector aluminum foil, the coating amount is 0.0194g / cm 2 , after drying at 85°C, cold pressing; then trimming, cutting, and slitting, drying at 85°C for 4 hours under vacuum conditions, welding the tabs, and making a lithium-ion secondary battery positive electrode that meets the requirements piece.

[0023] Preparation of lithium-ion secondary battery negative electrode sheet: graphite, conductive agent SuperP, thickener CMC, and adhesive SBR are prepared into a slurry at a mass ratio of 96.5:1.0:1.0:1.5, coated on the current collector copper foil and Dried at 85°C, the coating weight is 0.0089g / cm 2 ; After trimming, cutting, and slitting, dry at 110° C. for 4 hours under vacuum conditio...

Embodiment 2

[0027] The lithium ion secondary battery was prepared with reference to the method of Example 1, except that when preparing the lithium ion secondary battery electrolyte, the additives were: 1,3-propane sultone (PS) with a mass percentage content of 3% and mass The percentage content is 1% N-allyl succinimide.

Embodiment 3

[0029] The lithium ion secondary battery was prepared with reference to the method of Example 1, except that when preparing the electrolyte solution for the lithium ion secondary battery, the additive was: N-allyl succinimide with a mass percent content of 1%.

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