Guaranteeing the reliability of electric vehicle batteries in severe environments


Electric vehicles such as hybrid and EV vehicles are now widely used all over the world. Unsurprisingly, the percentage of hybrid vehicles is particularly high in Japan. Until just 20 years ago, vehicles powered by electricity were just a dream.
Automobiles are used in all regions and climates and must be able to function without failure in very harsh environments. Since batteries are essential to electric vehicles, they must be temperature monitored at all times to detect abnormalities. But in the beginning, there were no thermistor manufacturers able to realize such performance requirements as to temperature accuracy, responsiveness, and guaranteed reliability in harsh environments.

Efforts to address challenges

Since the dawn of electric vehicle development, SEMITEC has worked with customers in the study of specifications, trial production, assessment, etc. of thermistors for monitoring the condition of large batteries used in these vehicles. Through these efforts, SEMITEC succeeded in providing thermistors that meet the required quality, performance, and safety standards. Thermistors
were originally electronic components offering little resistance to external stresses, heat, moisture, etc. But post-processing such as insert molding and encasement made them strong and weather resistant. Through innovations such as the incorporation of metal heat collection plates and high heat conductive resins in the assembly structure, we increased temperature accuracy and responsiveness as well.
In addition, we responded flexibly to changes in the shape and structure of batteries, such as the shift from nickel-metal hydride to lithium-ion. As a result, our thermistors have been used in over 15 million electric vehicles and for more than 20 years.