Murata Manufacturing Co., Ltd.

Takamasa Ono

Sho Takahashi

Yukio Miyaki

Masaki Kuratsuka

Shoichi Nishiyama

Takashige Fujikawa

Ryuji Soeda

Atsushi Ouki

Masumi Fukuda

Yosuke Kono

Takahisa Ishimatsu

Atsushi Nemoto

Yoshihito Akiyama

Shinji Hayazaki

Takeo Asanuma

Takahiro Shirai

A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material. The electrolytic solution includes a multi-nitrile compound. The positive electrode active material includes a lithium-nickel composite oxide and a boron compound. The lithium-nickel composite oxide has a layered rock-salt crystal structure. The positive electrode active material has a crystallite size of a (104) plane that is greater than or equal to 40.0 nm and less than or equal to 74.5 nm. The crystallite size is calculated by X-ray diffractometry and Scherrer equation. The positive electrode active material has an element concentration ratio that is greater than or equal to 0.15 and less than or equal to 0.90. The element concentration ratio is calculated on the basis of a B1s spectrum, a Ni2pspectrum, a Co2spectrum, a Mn2spectrum, and an Al2spectrum of the positive electrode active material detected by X-ray photoelectron spectroscopy.

Secondary battery

A secondary battery includes outer package members each having flexibility and a battery device. The outer package members each include a thermal-fusion-bonding layer. The battery device is contained in an inside of the outer package members, and includes a positive electrode, a negative electrode, and an electrolytic solution. The outer package members are sealed at a thermal-fusion-bonding part. The thermal-fusion-bonding part is formed by the thermal-fusion-bonding layers being thermal-fusion-bonded to each other. The thermal-fusion-bonding layer includes polypropylene. The electrolytic solution includes a solvent and an electrolyte salt. The solvent includes a chain carboxylic acid ester. The thermal-fusion-bonding layer has a thickness of greater than or equal to 25 μm and less than or equal to 60 μm. The thermal-fusion-bonding part has a length of greater than or equal to 160 mm and less than or equal to 650 mm. The thermal-fusion-bonding part has a width of greater than or equal to 3 mm and less than or equal to 6 mm.

A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material layer. The positive electrode active material layer includes a lithium-nickel composite oxide of a layered rock-salt type.

Positive electrode for secondary battery, and secondary battery

A charging device is provided. The charging device switches to a (n+1)-th charging rate from a n-th charging rate when constant current charging is performed on a secondary battery at the n-th charging rate, at an SOC smaller than an SOC at which a voltage local minimum value appears when an experimental battery is charged at the n-th charging rate. The (n+1)-th charging rate is lower than the n-th charging rate, and n is a natural number.

Charging device, charging method, secondary battery, battery pack, electric vehicle, power storage device, electronic device, and power storage system using SOC

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Kyoto, Japan

Takamasa Ono