Search Results

We developed a high performance automotive lithium-ion battery and applied it to our new Toyota Intelligent Idling Stop System. This hybrid power management system has been introduced in the “intelligent package” of Toyota Vitz vehicles sold in Japan. The lithium-ion battery is installed under the seat on the passenger-side. The battery supplies electric power to the auxiliary electrical systems during the “idling stop” mode, and when restarting the engine. The main requirements of this battery are to supply high electric power output even at low temperatures and at the same time, maintain continuous power during charge and discharge cycling, and have long storage life. This performance has been accomplished successfully through a series of improvements in battery materials and structures.

In order to reduce traffic accident casualties, sophisticated safety systems have been developed and are continuously being upgraded in today's passenger vehicles. One system showing growth in the global automotive industry is a feature currently available on high-end passenger cars, Vehicle Stability Control (VSC). VSC can control side slipping, an unstable phenomenon which can lead to critical accidents. VSC systems are multi-functional systems that include an acceleration sensor to detect forces applied to the vehicle. Acceleration sensors sometimes referred to as G sensors are indispensable and are one of the key sensors for vehicle safety systems. New safety systems require acceleration sensors with high sensitivity and accuracy. We have achieved these increased requirements by adopting a unique stacked IC structure.

We have developed Li-ion battery heating system which is direct resistance heating for hybrid electric vehicles (HEV), plug-in hybrid vehicles (PHEV) and electric vehicles (EV) by use of an inverter and a motor. One relay is added between a positive terminal of Li-ion battery and one-phase (e.g. U-phase) of a three-phase motor. When additional relay is turned on, the motor coils, IGBTs (Insulated-gate bipolar transistor) and diodes in the inverter and a smoothing capacitor for the inverter constitute buck-boost DC to DC converter. IGBTs are controlled to repeat charging and discharging between the battery and the smoothing capacitor. We made a system prototype and examined battery heating capability. And also we optimized charging and discharging frequency from impedance and current to improve heat generation. This method can increase battery temperature from −20 degrees C to 0 degrees C in 5 minutes and can extend EV driving range.