Non-aqueous electrolyte battery

Abstract

A non-aqueous electrolyte battery is provided that achieves an improvement in safety, particularly an improvement in tolerance of the battery to overcharging, and also prevents discharge capacity from degrading, without compromising conventional battery designs considerably. The non-aqueous electrolyte battery has a positive electrode including a positive electrode active material-layer stack and a positive electrode current collector, a negative electrode including a negative electrode active material layer, and a separator interposed between the electrodes. The positive electrode active material-layer stack has two layers respectively having different positive electrode active materials. Of the two layers, a first positive electrode active material layer ( 11 ) that is nearer the positive electrode current collector ( 16 ) contains an olivine-type lithium phosphate compound as its positive electrode active material and uses VGCF ( 18 ) as a conductivity enhancing agent.

Description

technical field [0001] The present invention relates to improvement of nonaqueous electrolyte batteries such as lithium ion batteries and polymer batteries, and particularly relates to nonaqueous electrolyte batteries excellent in safety during overcharge. Background technique [0002] In recent years, the miniaturization and weight reduction of mobile information terminals such as mobile phones, notebook personal computers, and PDAs has been rapidly progressing, and batteries serving as driving power sources have been required to have higher capacities. Nonaqueous electrolyte batteries, which are charged and discharged by moving lithium ions between the positive and negative electrodes along with charging and discharging, have high energy density and high capacity, and are therefore widely used as driving power sources for mobile information terminals as described above. In addition, the recent use of its characteristics is not limited to mobile office applications such as ...

AI Technical Summary

Problems solved by technology

Therefore, when the filling density of the active material as described above is increased, since the penetration of the electrolyte into the electrode is greatly reduced, a local reaction occurs, especially the problem of lithium precipitation on the surface of the negative electrode, or due to electrolysis. The convection of the liquid deteriorates and the inside of the electrode is filled with heat, which reduces the heat dissipation. There is a tendency that the function cannot be fully exerted, and the decrease in safety becomes a problem.

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