Lithium secondary cell

Abstract

The present invention provides a lithium rechargeable battery including a negative electrode comprising a copper core material, to which is fixed an active material made by mixing artificial graphite particles A obtained by kneading and granulating a base material of pulverized bulk mesophase pitch with pitch in a softened state and / or thermosetting resin, carbonizing the resulting granules at 700 to 1,500 DEG C. and graphitizing the carbonized granules at 2,500 to 3,000 DEG C. with spherical graphite particles B having a high mean circularity, with a view to inhibiting the deterioration in battery capacity through the repeated charge / discharge cycles, which occurs remarkably in a high energy density lithium rechargeable battery, and providing excellent discharge characteristic and safety.

Description

technical field [0001] The present invention relates to lithium secondary batteries. Background technique [0002] As electronic devices become more portable and cordless, it is desired to use small, light weight lithium secondary batteries with high energy density as their driving power sources. For example, the so-called rocking chair type lithium-ion secondary battery has been put into practical use and is rapidly spreading. This lithium-ion secondary battery consists of a negative electrode that can reversibly absorb and release lithium ions as an active material, and a lithium-containing The transition metal composite oxide is used as the positive electrode of the active material, the separator and the non-aqueous electrolyte. [0003] Here, as for the negative electrode, graphite particles with high crystallinity have recently become the mainstream among various carbon materials. The reason is that graphite particles (1) have high electron conductivity and excellent d...

AI Technical Summary

Problems solved by technology

Therefore, there is a disadvantage that when the electrode is rolled to achieve a high density, the mixture layer is prone to fall off.

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