Envision Aesc Japan Ltd.

Automotive Energy Supply Corporation

Aesc Japan Ltd.

Toshihiro Horiuchi

Kenji Ohara

Masanori Aoyagi

Sohei Suga

Junko Nishiyama

Koichi Shinohara

Aika Kimura

Yosuke Kita

In a lithium ion secondary battery element, a positive electrode and a negative electrode are overlapped on each other so that a positive electrode active material layer with a generally rectangular shape in the positive electrode and a negative electrode active material layer with a generally rectangular shape in the negative electrode are overlapped on each other substantially perfectly and a positive electrode active material non-applied part of the positive electrode and a negative electrode active material non-applied part of the negative electrode are positioned on opposing sides of the rectangle. A border part between the negative electrode active material applied part and the negative electrode active material non-applied part is positioned closer to a peripheral side of a negative electrode current collector than a peripheral part of a positive electrode current collector. A border part between a negative electrode active material layer flat part and a negative electrode active material layer thin part is positioned closer to a central side of the negative electrode current collector than the peripheral part of the positive electrode current collector. The negative electrode active material layer thin part has a density that is equal to or smaller than that of the negative electrode active material layer flat part.

Lithium ion secondary battery element including negative electrode with negative electrode active material layer tapered part having smaller density than negative electrode active material layer flat part

A lithium ion secondary battery includes: a negative electrode having a carbon-based negative electrode material containing graphite particles and amorphous carbon particles; and a positive electrode including a lithium composite oxide. The lithium composite oxide is represented by a general formula: LiNiMnCoO, where x is a numeral of 1 or more and 1.2 or less, and y and z are positive numerals satisfying the relation of y+z&#x3c;1. The lithium composite oxide has a layer crystal structure and has a median particle diameter (D50) of 4.0 &#x3bc;m or more and less than 6.0 &#x3bc;m.

Lithium ion secondary battery

Provided is a lithium ion secondary battery including a power generating element that includes at least one positive electrode plate, at least one negative electrode plate, and at least one separator. A ratio B/A (m&#x3a9;cm) of volume resistivity B (m&#x3a9;cm) of the power generating element to an area A (cm) per one positive electrode plate is 0.4 or more and less than 0.9.

A negative electrode material for a lithium ion battery according to an embodiment of the present disclosure includes graphite particles and amorphous carbon particles. The graphite particles have a median diameter (D50) A of 8.0 &#x3bc;m or more and 11.0 &#x3bc;m or less. A ratio A/B of the median diameter A (&#x3bc;m) to a median diameter (D50) B (&#x3bc;m) of the amorphous carbon particles satisfies a relation of 1.1&#x3c;(A/B)&#x2264;2.75.

Negative electrode material for lithium ion battery

Provided is a lithium ion secondary battery including a power generation element, the power generation element including a positive electrode, a negative electrode, a separator, and an electrolyte solution, the positive electrode including a positive electrode current collector, and a positive electrode active material layer provided for the positive electrode current collector, the positive electrode active material layer including a positive electrode active material and binder, the negative electrode including a negative electrode current collector and a negative electrode active material layer provided for the negative electrode current collector, the negative electrode active material layer including a negative electrode active material and binder. The positive electrode has a volume resistivity in a range of 100 &#x3a9;cm or more and 700 &#x3a9;cm or less after at least one charging and discharging cycle.

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Zama, Japan

Toshihiro Horiuchi