IEC 62660-2 for cells and ISO 12405-1 and ISO/DIS 12405-2 for battery packs and systems are international standards for safety evaluation tests of lithium-ion batteries, which are beginning to be installed in vehicles. We conducted high-temperature endurance tests to verify the relevance of these test methods. The IEC test ends after the cell is held for 30 minutes at 130 oC. However, the test results indicated that the test should be extended until the battery cools to room temperature because one cell ignited while cooling after the test.

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We conducted fire tests on vehicles with lithium-ion batteries to collect data for examining measures to ensure safety during a vehicle fire. The maximum heat flux 1m from the vehicle and at a height of 1.2m was 12kW/m2 when accompanied by battery combustion, which is not significantly greater than that of gasoline-powered vehicles.

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The effect of different charge-discharge test profiles on lithium-ion battery life was investigated to verify the simple cycle-life-test (CLT) profile-generalization method developed by JARI. To verify the validity of our method, we measured the change of battery-cell performance (capacity and internal resistance) in an endurance cycle test by using a CLT profile and a reference profile (simulated charge-discharge cycle of a plug-in hybrid electric vehicle). The result did not indicate any clear differences in cell performance among test profiles, although there was very little performance degradation.

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[in Japanese]

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