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STMicroelectronics and LG Chem of Korea have unveiled an advanced automotive battery pack for electric and hybrid electric vehicles (HEVs). The device combines LG Chem's lithium ion (Li-ion) battery technology and with a battery management chip manufactured by ST.
Today's HEVs typically use batteries based on nickel metal hydride (NiMH) technology, which uses simpler control circuits but are heavier and operate at lower voltages. Li-ion batteries are widely used in portable consumer electronics because they offer a high energy-to-weight ratio (more than twice that of NiMH) with a very low self-discharge while not in use. However, their use in higher power applications has so far been limited because the charge/discharge cycle of Li-ion batteries must be carefully managed to protect the batteries from abuse. Thus, Li-ion batteries must be combined with sophisticated and highly reliable electronic battery-management circuits in high-power applications.
The new Li-ion battery pack from LG Chem manages the charge/discharge cycle with an advanced, economical, ST battery-management chip.
ST's battery-management chip is manufactured with the company's proprietary BCD (Bipolar-CMOS-DMOS) "smart-power" technology, which combines digital logic circuits, precise analog measurement and control circuits, and power-handling transistors on one silicon chip. A Battery Management System with these chips accurately controls the charging and discharging cycles of the battery to ensure safe operation and long battery life. Each chip can handle up to ten Li-ion cells and also includes an interface for communicating with other ST battery-management chips in the system—with as many as 32 battery-management chips connected in cascade to manage batteries that deliver up to 1,600V to vehicle electric motors.
ST was a pioneer in smart-power technology, having provided them for high-volume applications ranging from printers and fax machines to hard disk drives and the drivers that manage power windows and mirrors in cars.
The LG Chem/ST battery pack reduces cost and weight while increasing reliability, enabling Li-ion technology to address new applications from electric scooters and bicycles to heavy trucks.
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