A kind of double-layer composite diaphragm battery and its lithium replenishment method

Abstract

The invention provides a double-layer composite diaphragm battery, which includes a casing, a positive electrode, a negative electrode and an electrolyte located inside the casing, and is characterized in that a double-layer composite diaphragm is arranged between the positive electrode and the negative electrode. The composite diaphragm insulates and isolates the positive electrode and the negative electrode; the double-layer composite diaphragm includes a first diaphragm, a second diaphragm and an active lithium layer, and the active lithium layer is interposed between the first diaphragm and the second diaphragm; It includes a positive pole tab, a negative pole tab, and a lithium-supplementing tab, and the other ends of the positive pole tab, the negative pole tab, and the lithium-filling tab all extend out of the housing or the other end of the positive pole tab and the negative pole tab One end extends out of the housing. The reaction speed of the double-layer composite diaphragm battery provided by the present invention is controllable during lithium supplementation, and the lithium intercalation speed is uniform, which can realize uniform lithium supplementation, improve the first charge and discharge efficiency and energy density of the battery; the operation of lithium supplementation is simple and convenient, and cumbersome supplementation can be avoided. The lithium process saves time and effort; and has no effect on the entire battery preparation process, and the cost is low.

Description

technical field [0001] The invention relates to the technical field of new energy, in particular to a double-layer composite diaphragm battery and a method for replenishing lithium therefor. Background technique [0002] Compared with other secondary batteries, lithium-ion batteries have the advantages of high voltage, high energy density, long cycle life and good safety performance, and become the most widely used rechargeable batteries, such as portable electronic products, electric vehicles and other large mobile devices. Power Battery. At present, the mature battery negative electrode materials are mainly graphite materials. After years of development, its energy density has been developed to a level close to the theoretical value (theoretical specific capacity is 372mAh / g), which limits the further improvement of the battery energy density and cannot meet the needs of the future. Batteries require high energy density. [0003] Nano-silicon (theoretical capacity 4200mA...

AI Technical Summary

Problems solved by technology

However, since lithium is a very active metal, after adding lithium metal to the electrolyte by this method, the reaction speed is very fast, and the speed of lithium intercalation is uncontrollable, which leads to the instability of the formed SEI film, which easily causes the rupture of the negative electrode material, and the effect of lithium supplementation is poor. Difference

In addition, some lithium metal particles remaining on the electrode surface will pierce the separator and cause battery safety hazards.

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