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Lithium-ion cells are being used in an increasing number of electric and hybrid vehicles. Both of these vehicle types contain many cells. Despite various safety measures, however, there are still reports of accidents involving abnormal heat, smoke, and fire caused by thermal runaway in the cells. If thermal runaway in one cell triggers that of another and thus causes thermal runaway propagation, this can lead to rupture of the battery pack, car fire, or other serious accidents. This study is aimed to ensure the safety of vehicles with lithium-ion cells by clarifying such accident risks, and so we investigated the process of thermal runaway propagation. In the experiment, we created a battery module made of seven laminate-type cells tightly stacked one on another. Then, we induced thermal runaway in one of the cells, measured the surface temperatures of the cells, and collected video data as the process developed. As a result, all of the seven cells underwent thermal runaway.

Recently, vehicles with high capacity traction batteries for driving such as Ni-MH, lithium-ion have come to be produced in the world. However, the damage has not been clarified in the case of these vehicles fire by a traffic accident or arson. In particular, lithium-ion cells in high temperature environment may cause a thermal runaway which emits smoke or flare. Therefore, it is necessary to examine what kinds of phenomena occur when a vehicle with a lithium-ion battery catches fire. In this paper, the authors studied the situation and temperature characteristics of a hybrid electric vehicle fire to investigate the temperature input to a lithium-ion battery on a vehicle. We assumed an accident that gasoline leaking from other vehicle would be spread under a vehicle and ignited. In a vehicle fire test, gasoline was spread under a hybrid electric vehicle without the traction battery instead of a vehicle with lithium-ion battery, and ignited.

Recently, study of electromagnetic compatibility (EMC) for vehicles has become more and more important. In this paper, the authors examine the potential effectiveness of the finite difference time domain (FDTD) method, one method for simulating an electromagnetic field, as a tool to analyze automotive EMC. The authors have calculated the electromagnetic field for a strip line, and examined the effectiveness of the calculation method by comparing the calculations with measurements. Consequently, the calculated trends of the spacial distribution of the electrical field surrounding the strip line are approximately equal to the measured trends. The calculations of the S-parameter are very close to the measurements in the 20 to 200 MHz frequency range.

This paper analyzes the subjective evaluation of the lighting of the auxiliary lamps of a motorcycle on the basis of the data collected in field experiments. Two types of experiments were conducted: 1) To investigate the effect of various positions of the auxiliary lamps on a motorcycle, and 2) To determine the influence of various luminous intensities of the lamps. For example, the subjects were instructed to judge how they felt about the appropriateness of the auxiliary lamps according to the 5-interval integer rating scale. After the tests, the authors made non-linear interpolations of the data by means of three-layered neural networks. This analysis presents considerable information about the appropriateness of the auxiliary lamps in regards to their positions on the motorcycle and their luminous intensities in daytime and nighttime conditions respectively.

The intent of this paper is to present the actual electromagnetic environment on public roads in Japan. Field strengths in the frequency range from 10kHz to 1000MHz were measured using the measurement equipment composed of a field strength meter and a spectrum analyzer for three years from 1988 to 1990. About 170 transmission stations and about 20 facilities were measured, and traveling distance over which the field strengths were measured was about 5,000km. After a great many investigations, the electromagnetic environment on public roads was able to be understood quantitatively.