A long-life lithium-ion power battery and preparation method thereof

Abstract

The invention provides a long-life lithium-ion power battery. The lithium-ion power battery includes a positive electrode sheet and a negative electrode sheet; the positive electrode sheet includes a positive electrode current collector and a positive electrode slurry arranged on the surface of the positive electrode current collector. By weight percentage, the positive electrode The slurry includes the following components: 92-98.5% nickel-cobalt lithium aluminate, 0.5-2% conductive carbon black, 0.5-2% niobium phosphide and 0.5-4% polyvinylidene fluoride; The negative electrode slurry on the surface of the negative electrode collector, by weight percentage, the negative electrode slurry includes the following components: negative electrode material 92-98%, sodium carboxymethyl cellulose 0.5-2%, styrene-butadiene rubber 0.5-2% , conductive carbon black 0.5‑2% and niobium phosphide 0.5‑2%. The long-life lithium-ion power battery of the present invention raises the safety, rate and cycle of the battery cell to a new level, and its comprehensive performance fully meets the requirements of national standards.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a long-life lithium ion power battery and a preparation method thereof. Background technique [0002] Lithium-ion power battery is a new type of high-energy battery successfully developed in the 20th century. Because of its advantages such as high energy, high battery voltage, wide operating temperature range, and long storage life, it has been widely used in military and civilian small electrical appliances. [0003] For lithium-ion power batteries, the positive electrode material can be a ternary composite material. The ternary composite positive electrode material is made of nickel salt, cobalt salt, aluminum salt, and manganese salt. The ratio of nickel, cobalt, and manganese can be adjusted according to actual needs. The battery with ternary material as positive electrode is safer than lithium cobalt oxide battery. [0004] However, the processing performance of the exi...

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Problems solved by technology

[0004] However, the processing performance of the existing lithium-ion power batteries is unstable, because the ternary materials have high requirements on the humidity of the production environment, and the slurry is prone to thickening after absorbing water, resulting in unstable coating surface density and poor product qualification rate. At the same time, there is a local heat island in the electrode, which leads to a serious performance decline; at the same time, the safety performance and high-rate charge-discharge cycle performance of existing products are poor. The specific performance is: in the battery acupuncture test, the pass rate is low; the battery The thermal stability of the battery is poor, and thermal diffusion is prone to occur after an internal short circuit, resulting in explosion and fire; the cycle performance of the battery is poor, 1C charge 5C discharge is less than 1000 cycles, the power performance is low, the battery discharge platform is as low as 3.6V, and the weight ratio is low. to 506Wh / Kg