Resistance increase factors of calendar-life tests were studied by electrochemical impedance spectroscopic (EIS) measurements of commercial lithium-ion cells composed of a LiNi1/3Co1/3Mn1/3O2 cathode and a graphite anode. The capacity faded rapidly at high temperature (50°C). In contrast, increased internal resistance was not affected by high temperature. The EIS measurements indicated that the cathode charge-transfer resistance increases at 25°C and the solution resistance increases at 50°C. These results revealed that the increase factors of internal resistance change with the temperature of calendar-life tests.

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This study seeks to establish methods to assess the contribution of hydrocarbon components in exhaust particles to the oxidative potential. Two treatments were tested: heat treatment and C18 cartridge column treatment. We confirmed that both treatments were useful, but in the heat treatment, it might be necessary to prevent denaturation of the sample by heating. Furthermore, we demonstrated that the hydrocarbon component of DEP in this study contributed significantly to the oxidative potential.

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[in Japanese]

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