Hitachi Metals, Ltd.

Hitachi, Ltd.

Xiaoliang Feng

Akira Gunji

Takashi Nakabayashi

Shuichi Takano

Hisato Tokoro

Shin Takahashi

Tatsuya Toyama

Sho Furutsuki

Osamu Kubota

Akihide Tanaka

Tatsuya Tooyama

A compound having a layered structure that is used for a positive electrode active material for a lithium ion secondary battery achieves both a high energy density and a high cyclability. The positive electrode active material for a lithium ion secondary battery contains a compound having a layered structure belonging to a space group R-3m, in which the compound having a layered structure is represented by a compositional formula: LiM1Owherein M1 represents a metal element or metal elements other than Li, and contains at least Ni, &#x2212;0.03&#x2264;a&#x2264;0.10, and &#x2212;0.1&#x3c;&#x3b1;&#x3c;0.1, a proportion of Ni in M1 is larger than 70 atom %, and a site occupancy of a transition metal or transition metals at a 3a site obtained by structural analysis by a Rietveld method is less than 2%, and a content of residual lithium hydroxide in the positive electrode active material is 1 mass % or less.

Positive electrode active material for lithium ion secondary battery, manufacturing method thereof, and lithium ion secondary battery

Provided are a cathode active material used for a lithium ion secondary battery having a high discharge capacity, and a small increase in internal resistance caused following charge/discharge cycles; a method for producing the same; and a lithium ion secondary battery. The cathode active material has a layered structure assigned to a space group of R-3m represented by the formula: LiM1O(where M1 represents metal elements other than Li containing at least Ni, &#x2212;0.05&#x2264;a&#x2264;0.15, &#x2212;0.1&#x2264;&#x3b1;&#x2264;0.1). A content of Ni is 70 atom % or more, and a generating amount of oxygen gas in the range from 200&#xb0; C. to 450&#xb0; C. is 30 mass ppm or less. The method comprises the steps of grinding and mixing a lithium raw material, and firing the resultant mixture in the range of 650&#xb0; C. or more and 900&#xb0; C. or less.

Cathode active material used for lithium ion secondary battery, method for producing same, and lithium ion secondary battery

A positive electrode active material includes a primary particle represented by Compositional Formula (1):NiCoMO&#x2003;&#x2003;(1),where x is a number satisfying a relation represented by an expression &#x2212;0.12&#x2264;x&#x2264;0.2; y is a number satisfying a relation represented by an expression 0.7&#x2264;y&#x2264;0.9; z is a number satisfying a relation represented by an expression 0.05&#x2264;z&#x2264;0.3; and M is at least one element selected from the group consisting of Mg, Al, Ti, Mn, Zr, Mo, and Nb; or a secondary particle into which the primary particle aggregates. The primary particle or the secondary particle includes a free lithium compound in a weight proportion of 0.1% or more and 2.0% or less, and the weight of lithium hydroxide in the free lithium compound is 60% or less of the weight of lithium carbonate in the free lithium compound.

Positive electrode active material for lithium ion secondary battery, and positive electrode for lithium ion secondary battery and lithium ion secondary battery comprising the same

Provided are a cathode material for lithium ion secondary battery having excellent rate characteristics and cycle characteristics while a cathode active substance has high density, and a lithium ion secondary battery cathode and a lithium ion secondary battery that use the above cathode material. The cathode material for lithium ion secondary battery (), represented by LiM1M2O[where &#x2212;0.1&#x2264;x&#x2264;0.3, 0&#x2264;y&#x2264;0.1; M1 is Ni, Co, Mn; and M2 is Mg, Al, Ti, Zr, Mo, Nb, Fe, B], is an agglomerate including secondary particles () both formed via aggregation of lithium metal composite oxide primary particles () having a layered structure. A mean porosity of the secondary particles having a particle size of more than 10 &#x3bc;m and equal to 50 &#x3bc;m or less is higher than that of the secondary particles having a particle size of 0.5 &#x3bc;m to 10 &#x3bc;m.

Lithium ion secondary battery cathode material, lithium ion secondary battery cathode and lithium ion secondary battery that use same, and method for manufacturing lithium ion secondary battery cathode material

In a charging control system for recording data regarding charging a secondary battery, a status recording unit refers the charging voltage value and the charging current value and records the referred charging voltage, the referred charging current and reference time when the charging current value is referred and time when the charging voltage value is referred, on the recording unit. A battery protecting unit stops the charging the secondary battery when the charging voltage exceeds the predetermined target voltage value. The status recording unit starts recording of the charging voltage value, the charging current value, and the reference time on the recording unit, when the charging voltage exceeds the target voltage value as a result of a fail in stopping the charging by the battery protecting unit because of occurrence of a trouble in the battery protecting unit.

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Tokyo, Japan

Xiaoliang Feng