A small hybrid system was developed for the 2009 model hybrid vehicle. The Intelligent Power Unit (IPU), which consists of a high-voltage battery and a Power Control Unit (PCU), occupies 19% less volume and is 28% lighter than the previous model(1).
In order to reduce the size and weight of the IPU, the number of nickel-metal hydride battery modules was reduced, enabling the battery box to be made smaller and lighter. In order to provide the necessary output with fewer battery modules, the length of the battery electrodes was increased, thus raising the output from each battery module. The volume and weight of the PCU were reduced by integrating the inverter, DC-DC converter, and ECU into a single package.
The size reduction of the IPU enabled the IPU to be installed at the bottom of the luggage compartment. As a result, the available space in the luggage compartment is the same as that of a conventional vehicle.