Kabushiki Kaisha Toyota Chuo Kenkyusho

Takao Inoue

Chikaaki Okuda

Nobuhiro Ogihara

Naoki Baba

An electrode active material of the present invention is made of a layered composition including organic backbone layers containing an aromatic compound that is a dicarboxylic acid anion having a naphthalene backbone; and alkali metal element layers containing an alkali metal element coordinated to oxygen contained in the carboxylic acid anion to form a backbone. The layered composition has an interplanar spacing between (002) planes of 0.42400 to 0.42800 nm, an interplanar spacing between (102) planes of 0.37000 to 0.37600 nm, an interplanar spacing between (211) planes of 0.32250 to 0.32650 nm, and an interplanar spacing between (112) planes of 0.30400 to 0.30700 nm, as measured by X-ray diffraction. Preferably, the layered composition has an interplanar spacing between (200) planes of 0.50500 to 0.50950 nm as measured by X-ray diffraction.

Electrode active material, nonaqueous secondary battery electrode, and nonaqueous secondary battery

An electric power storage systemof the present invention includes a lithium secondary battery; a detection device to detect the temperature of the lithium secondary battery; and a control device to decrease a remaining capacity of the lithium secondary battery based on an increase of the detected temperature and a temperature Tbx of the lithium secondary battery. When a self-heating rate of the lithium secondary battery at a temperature T (K) and a remaining capacity x (%) is represented by Hs(x, T) (K/min), and a heat dissipation rate at a temperature T (K) of the lithium secondary battery is represented by Hd(T) (K/min), the temperature Tbx is a temperature at which Hs(x,Tbx)&#x3e;Hd(Tbx) holds. That is, this temperature Tbx is a temperature at which the heat generating rate is higher than the heat dissipation rate and at which the battery temperature T starts to increase.

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Nagakute, Japan

Takao Inoue