Modified polyimide secondary battery adhesive and preparation method thereof

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a modified polyimide secondary battery adhesive and a preparation method thereof. The secondary battery adhesive is prepared from the following raw materials: polyimide powder, a lipid compound and a positive electrode material, the polyimide powder is prepared from the following raw materials: an organic amine compound, an additive, a heteroaromatic compound, acid anhydride, an aprotic polar solvent, an ultra-dry solvent, a nitrogen-containing organic compound and an acetylation reagent. Polyimide is modified by adding a compound containing an epoxy group, so that the prepared adhesive contains a large number of polyimide structures, the dimensional stability and heat resistance of the adhesive in an electrolyte are ensured, and meanwhile, the adhesive force of the adhesive on a copper foil can be effectively improved by a molecular chain segment containing the epoxy structure. The prepared modified polyimide secondary battery adhesive is applied to a lithium ion battery, and the electrochemical performance and safety of the battery can be effectively improved.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to the field of IPC H01M4, and more particularly, to a modified polyimide secondary battery adhesive and a preparation method thereof. Background technique [0002] Lithium-ion secondary batteries are widely used due to their high energy density and no memory effect. Binders are an important component in the manufacturing process of lithium batteries and have received more and more attention. At present, the commonly used binder is polyvinylidene fluoride (PVDF). PVDF has good electrochemical stability, but its mechanical properties are poor and cannot adapt to the volume expansion of these materials. The active material often falls off, causing the battery The sudden reduction in capacity will also cause battery safety problems. [0003] Polyimide is used as a binder in lithium-ion batteries, which can effectively improve the electrochemical performance and safety o...

AI Technical Summary

Problems solved by technology

At present, the commonly used binder is polyvinylidene fluoride (PVDF). Polyvinylidene fluoride has good electrochemical stability, but its mechanical properties are poor and cannot adapt to the volume expansion of these materials. Active materials often fall off and lead to battery failure. Sudden reduction in capacity will also cause battery safety issues

[0003] Polyimide is used as a binder in lithium-ion batteries, which can effectively improve the electrochemical performance and safety of batteries, but there are also obvious shortcomings in the use process that need to be solved

For example: the temperature required in the preparation process is too high, and the positive electrode material cannot withstand such a high temperature, which affects the electrochemical performance of the battery; soluble polyimide will swell in the electrolyte, resulting in poor electrochemical performance; Poor adhesion of polyimide

[0004] In the prior art, the patent application document with the application publication number CN 113121823A discloses a conductive adhesive for lithium-ion batteries and a preparation method thereof. By introducing long chains of aliphatic groups, the polymer adhesive is improved in water environment. Causes the phenomenon of gelation, improves the electrochemical performance of lithium-ion batteries, but does not improve its adhesive performance much

[0005] The patent application document with the application publication number CN 112563470A discloses a lithium battery positive electrode sheet and its preparation method and application. Two polyimides with different molecular weights are mixed to improve the safety of the lithium ion battery positive electrode sheet. However, there is no improvement in its electrochemical stability and adhesion performance

Images