リチウム二次電池

Abstract

PROBLEM TO BE SOLVED: To provide a lithium secondary battery combining storage characteristics and overcharge safety in which the electrolyte contains a gas generation additive, and sufficient gas emission can be ensured during over charge even when positive electrode active material containing tungsten is used.SOLUTION: The lithium secondary battery includes a positive electrode containing a positive electrode active material and a conductive material, a negative electrode containing a negative electrode active material, and a nonaqueous electrolyte containing a gas generation additive. The positive electrode active material is a granular lithium transition metal composite oxide having a layer structure containing tungsten (W), and the conductive material has a form of aggregate where primary particles gathers. Since the average particle size of the aggregate is controlled within the range of less than 9 μm, emission of gas due to decomposition of the gas generation additive under existence of the aggregate is controlled.
【課題】電解質にガス発生添加剤を含み、かつ、タングステンを含む正極活物質を用いた場合でも過充電時に十分なガス発生量を確保することのできる、保存特性と過充電安全性とを兼ね備えたリチウム二次電池を提供する。 【解決手段】 正極活物質および導電材を含む正極と、負極活物質を含む負極と、炭化水素化合物からなるガス発生添加剤を含む非水電解質とを備えるリチウム二次電池であって、正極活物質は、タングステン(W)を含み層状構造を有する粒状のリチウム遷移金属複合酸化物であって、導電材は、一次粒子が集まった凝集体の形態を有しており、凝集体の平均粒径が9μm未満の範囲で制御されることで、凝集体の存在下で前記ガス発生添加剤の分解に起因して発生されるガスの発生量が制御されているリチウム二次電池とする。 【選択図】図7

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Cited By (2)

    Publication numberPublication dateAssigneeTitle
    WO-2015037111-A1March 19, 2015株式会社日立製作所Positive-electrode active material for use in lithium-ion secondary batteries and lithium-ion secondary battery using said positive-electrode active material
    WO-2016067522-A1May 06, 2016三洋電機株式会社Nonaqueous electrolyte secondary battery