Nonaqueous electrolyte secondary battery

Abstract

The invention provides a nonaqueous electrolyte secondary battery with a small increase in internal resistance and less gas generation during high-temperature charged storage, and with a high residual capacity, when using a non-aqueous electrolyte containing a nitrile group-containing compound. The nonaqueous electrolyte secondary battery includes a positive electrode plate containing positive electrode active material, a negative electrode plate containing negative electrode active material, a nonaqueous electrolyte containing a nitrile group-containing compound, and a separator provided between the positive electrode plate and the negative electrode plate, and is also provided with a layer of inorganic particles between the positive electrode plate and the separator or between the negative electrode plate and the separator. It is preferable that the layer of inorganic particles be formed on a surface of the positive electrode plate.

Description

technical field [0001] The present invention relates to a non-aqueous electrolyte secondary battery, in particular to a non-aqueous electrolyte secondary battery in which internal resistance increases during high-temperature charge storage when a non-aqueous electrolyte containing a compound containing a nitrile group is used And the amount of gas generated is small, and the capacity residual rate is large. Background technique [0002] It is widely used as a drive power source for portable electronic devices such as mobile phones, portable personal computers, and portable music players, and as a power source for hybrid electric vehicles (HEV) or electric vehicles (EV). Lithium-ion secondary batteries having high energy density and high capacity are representative non-aqueous electrolyte secondary batteries. [0003] As the positive electrode active material of these non-aqueous electrolyte secondary batteries, LiCoO, which can reversibly store and release lithium ions, can...

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Problems solved by technology

[0017] In addition, if the surface of the positive electrode active material particle is coated with Al 2 o 3 , ZrO 2 If the inorganic substance coating layer is covered, since these inorganic substance coating layers are insulators and do not participate in the electrode reaction, the capacity per unit volume of the battery will decrease, and the internal resistance will increase.

Moreover, in the above-mentioned Patent Document 5, there is no disclosure of the state of gas generation during high-temperature charge storage when a non-aqueous electrolyte to which a nitrile group-containing compound is added is used.

[0018] In addition, in the above-mentioned Patent Document 6, a separator capable of improving the high-temperature charging and storage characteristics of a nonaqueous electrolyte secondary battery is given, and the separator is composed of a laminated film of two or more layers containing polyethylene and polypropylene, and inorganic particles become In the state of being dispersed in a polyolefin microporous membrane containing polypropylene, the effect of capturing decomposition products by inorganic particles as described below cannot be sufficiently obtained

Moreover, in the above cited document 6, there is no disclosure about gas generation and increase in internal resistance during high-temperature charge storage when using a non-aqueous electrolyte to which a nitrile group-containing compound is added.

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