DENSO Corporation has developed three components for hybrid vehicles that are smaller, lighter and deliver better performance: a dc-dc converter, a battery-monitoring unit and a system main relay.
The Lexus GS450h, with these components installed, was launched in Japan in March.
The components will be introduced worldwide on the Lexus GS450h, with the vehicle's launch in the USA in April and in Europe in May.
The dc-dc converter converts the high voltage (288V) supplied by the main battery to a lower voltage to charge a 12V auxiliary battery and supply electric power to various accessories such as headlamps, wipers and the horn.
For its new dc-dc converter, Denso developed a unique power conversion circuit that reduces energy loss by half compared to a conventional dc-dc converter, decreasing the amount of heat generated during power conversion and improving fuel consumption.
This enables the dc-dc converter to be cooled by air instead of the conventional method of cooling by water, allowing more flexibility in installation location.
The battery-monitoring unit monitors the voltage, current and temperature of the high-voltage battery.
Conventional battery-monitoring units place only low voltage elements on both sides of the circuit board.
Denso's new battery-monitoring unit places not only low voltage elements but also high voltage elements on both sides of the circuit board. This, along with reducing the number of elements, enables the new battery-monitoring unit to be approximately 65% smaller and approximately 50% lighter than conventional products.
System main relay
The system main relay connects and disconnects electric currents between the high-voltage battery and high-voltage system by controlling the contact of movable and fixed parts.
It also shuts off the high electrical voltage in a collision to secure the safety of vehicle occupants.
Denso's newly developed system main relay reduces operation noise by approximately 10dB by using a structure that lessens the impact when a movable part comes into contact with a fixed part, without slowing the speed in shutting off the high electrical voltage in a collision.
Denso also reduced the number of components used in the product, making assembly easier.
In addition to dc-dc converters, battery monitoring units and system main relays, Denso has developed several other hybrid components including boost converters for inverters, electric compressors and hybrid computers.