Non-aqueous electrolyte secondary battery

Abstract

A non-aqueous electrolyte secondary battery has a positive electrode having a positive electrode collector, on which a positive electrode active material layer containing a positive electrode active material as a complex oxide of Li and transition metals are formed, and a negative electrode having a negative collector, on which a negative electrode active material layer is formed. The non-aqueous electrolyte secondary battery is a gel or solid non-aqueous electrolyte secondary battery having a battery device in which a positive electrode and a negative electrode are laminated with an electrolyte layer therebetween in a film-state packaging member constructed by metal foil laminated films, and containing a lithium salt, a non-aqueous solvent, and a polymer material. The concentration in mass ratio of a free acid in the electrolyte layer is 60 ppm and less. Average particle diameter of the positive electrode active material lies in a range from 10 to 22 μm, the minimum particle diameter is 5 μm or larger, the maximum particle diameter is 50 μm or smaller, and specific surface of the positive electrode active material is 0.25 m2 / g or smaller. Lithium carbonate (Li2CO3) contained in the positive electrode active material is 0.15 percent by weight and less. Moisture contained in the positive electrode active material is 300 ppm and less.

Description

RELATED APPLICATION DATA [0001] The present application claims priority to Japanese Applications Nos. P2000-102624 filed Apr. 4, 2000, P2000-108412 filed Apr. 10, 2000, and P2000-111044 filed Apr. 12, 2000, which applications are incorporated herein by reference to the extent permitted by law. BACKGROUND OF THE INVENTION [0002] The present invention relates to a battery in which a battery device having electrolyte as well as a positive electrode and a negative electrode is sealed in a film-state packaging member. [0003] In recent years, a secondary battery used as a power source of a portable electronic device has been actively studied and developed. Among the secondary batteries, attention is paid on a lithium secondary battery and a lithium ion secondary battery as secondary batteries capable of realizing high energy density. Conventionally, each of each secondary batteries is generally constructed by interposing a liquid electrolyte (hereinbelow, also called electrolyte solution)...

AI Technical Summary

Benefits of technology

[0011] The invention has been achieved in consideration of the problems and its object is to provide a battery capable of suppressing shape change and suppressing deterioration in battery characteristics.

[0012] Another object of the invention is to provide a positive electrode active material capable of suppressing expansion of a battery and a non-aqueous electrolyte secondary battery using the positive electrode active material.

Problems solved by technology

When a hard case cell made of a metal is used, a problem such that strong recent demands of a lighter, smaller, and thinner secondary battery are not sufficiently addressed occurs.

When a metal hard case cell is used, the demand regarding shape cannot be also sufficiently addressed.

As described above, when the non-aqueous solution is used, a problem such as leakage occurs.

In the case of using a film-state case such as a laminated film, a polymer film, or a metal film obtained by covering metal foil made of aluminum or the like with a resin as a packaging member, however, when lithium hexafluorophosphate (LiPF6), lithium tetrafluoroboric acid (LiBF4), or the like is used as a lithium salt, a problem such as a battery expansion occurs.

When the free acid component reacts with the lithium to form lithium fluoride (LiF) or the like and the lithium in the battery system is consumed, problems such that shelf stability or charge / discharge cycle characteristic deteriorates and a theoretical battery capacity cannot be obtained, occur.

A secondary battery using a non-aqueous gel electrolyte or solid electrolyte housed in a metal foil laminate case has a significant challenge to suppress expansion which is seen in a high temperature storage test or the like since a housing for accommodating the aluminum laminate pack may be broken due to the expansion.

A non-aqueous gel polymer secondary battery using a metal foil laminate pack obtained by covering metal foil such as aluminum foil with a resin has a significant challenge to suppress expansion, which is seen in a high temperature storage test or the like since there is the possibility that an aluminum laminate pack is not housed in a set case due to the expansion.

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