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 percent smaller and approximately 50 percent lighter than conventional products.

The battery ECU also detects:

• main battery abnormalities
• degree of the main battery deterioration
• accidental electrical connection between the high-voltage part and the body

DENSO provides battery ECUs for nickel metal hydride batteries as well as lithium ion batteries.

Benefits and Features

• Quick and precise voltage detection
  • In 2003, DENSO developed a new voltage detection circuit that more quickly and precisely detects voltages than a conventional circuit, while maintaining the insulating property between the high-voltage and low-voltage sides in the battery ECU. Compared to a conventional circuit, DENSO achieved an approximately 50 percent reduction in voltage detection time and voltage detection error.
• Small size and light weight
  • The newly developed voltage detection circuit has a simple structure composed only of switching elements and condensers, significantly reducing the size and weight of the battery ECU.

Specifications for Nickel Metal Hydride Battery

Operating temperature	-30 to 80 degrees
Voltage detection time	4 milliseconds per one channel
Voltage detection accuracy	0.6 percent
Size	170 X 140 X 39 millimeters
Weight	400 grams