Gel polymer lithium ion battery

Abstract

The invention belongs to the technical field of lithium ion batteries, in particular relates to a gel polymer lithium ion battery which comprises a gel polymer electrolyte, a cathode, an anode and a diaphragm between the cathode and the anode, wherein the gel polymer electrolyte comprises a lithium salt, a non-aqueous solvent and a polymer monomer; the polymer monomer contains at least one epoxy monomer containing epoxy groups and double bonds and at least one acrylic ester monomer; an anode adhesive comprises a polymer of which the main chain or side chain contains amino groups or imino groups. Compared with the prior art, by introducing the epoxy compound as a monomer and adopting a polymer containing amino groups or imino groups as an anode adhesive (epoxy groups react with the amino groups or imino groups to form a cross-linked network), the gel polymer electrotype can be tightly connected with the anode, thus improving the mechanical strength and deformability resistance of the battery, greatly reducing interface impedance of the battery and enhancing the cycle performance and the dynamic performance of the battery.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, in particular to a gel polymer lithium ion battery. Background technique [0002] The electrolyte of currently commercially available lithium-ion batteries generally includes non-aqueous solvents, lithium salts, and additives. Since the non-aqueous solvents are liquid, when the battery is impacted by the outside or the battery itself expands internally, the liquid electrolyte is easily released from the battery. Leaking out of the battery, and the organic solvent itself has the characteristics of flammability, so lithium-ion batteries using liquid electrolytes have potential safety hazards such as explosions. [0003] On the contrary, the gel polymer electrolyte has a jelly-like appearance, and there is no free-flowing liquid inside, so the lithium-ion battery using it has no leakage problem and has relatively high safety. The liquid electrolyte of the gel polymer electrolyte is bo...

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Problems solved by technology

[0005] However, the above-mentioned patent applications all have the following problems: due to the low surface energy of graphite as the anode active material, and more than 90% of the components in the gel polymer electrolyte are organic solvents, resulting in the adhesion of the gel polymer electrolyte to the anode very little force

During the cycle, due to the continuous intercalation and extraction of lithium by the anode active material, such as graphite, both the anode and the gel polymer electrolyte expand, but the expansion coefficients of the two are different, which leads to the continuous deterioration of the electrolyte / graphite interface, resulting in battery failure. Increased impedance and poor cycle performance; in addition, the poor adhesion between the gel polymer electrolyte and the anode will also make large and thin batteries easily deformed, resulting in poor safety performance

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