Vehicle Energy Japan Inc.

Hitachi Automotive Systems, Ltd.

Yuki Takei

Shuichi Suzuki

Takeshi Miki

Hironori Sasaki

Yoshimasa Koishikawa

Ikuo Ozaki

Yoshihisa Okuda

Yusuke Tachikawa

Provided is a positive electrode for a lithium ion secondary battery that suppresses both a decrease in discharge capacity and an increase in internal resistance due to charging and discharging. The positive electrode for the lithium ion secondary battery includes a positive-electrode current collector and a layered structure provided on the positive-electrode current collector, in which the outermost layer of the layered structure contains a first positive-electrode active material represented by LiMOwherein X satisfies −0.15≤X≤0.15, Mrepresents an element group including Ni, Co, and Mn, and the innermost layer of the layered structure contains a second positive-electrode active material represented by LiMOwherein Y satisfies −0.15≤Y≤0.15, and Mrepresents an element group including Ni, Co, and at least one of Mn or Al.

Positive electrode for lithium ion secondary batteries, and lithium ion secondary battery

Provided is a positive electrode for lithium ion secondary cell that includes an electrolyte holding layer excellent in electron conductivity, and a lithium ion secondary cell using the same. The present invention relates to a positive electrode for lithium ion secondary cell that includes a positive electrode current collector foil and positive electrode mixture layers laminated on both surfaces of the positive electrode current collector foil. The positive electrode mixture layer includes a first positive electrode active material layer, an electrolyte holding layer, and a second positive electrode active material layer. The first positive electrode active material layer, the electrolyte holding layer, and the second positive electrode active material layer contain positive electrode active materials, binders, and conductive agents containing carbonaceous material. A conductive agent ratio of the electrolyte holding layer is higher than conductive agent ratios of the first positive electrode active material layer and the second positive electrode active material layer. A positive electrode active material ratio and a binder ratio of the electrolyte holding layer are lower than positive electrode active material ratios and binder ratios of the first positive electrode active material layer and the second positive electrode active material layer.

Positive electrode for lithium ion secondary cell, and lithium ion secondary cell using same

A positive electrode capable of achieving both of high volumetric energy density and high volumetric power density and a lithium ion secondary battery using the same are provided. A lithium ion secondary battery includes a positive electrode including a current collector with a positive active material mixture layer applied on both faces thereof, the positive active material mixture layer including active material particles, conductive additive particles and a binder. The active material particles used have a value D of an average particle diameter D50 of the active material particles in the range from 1 to 10 &#x3bc;m. The ratio b/a of the volume fraction b of the vacancy volume in the positive active material mixture layer to the volume fraction a of the active material particles in the positive active material mixture layer is in the range of &#x2212;0.01D+0.57&#x2266;b/a&#x2266;&#x2212;0.01D+0.97.

Lithium ion secondary battery

Growing community of inventors

Hitachinaka, Japan

Yuki Takei