LG Chem and STMicroelectronics Drive to Improve Battery Technologies for Hybrid Electric Vehicles
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Hybrid electric vehicles, which combine a conventional petrol-fueled Internal Combustion Engine with an electric-motor powered by a rechargeable battery, are becoming an increasingly important part of the automotive market because they can deliver greater fuel efficiency and reduce atmospheric pollution. Typically, today's HEVs use batteries based on Nickel Metal Hydride (NiMH) technology, which use simpler control circuits but are heavier and operate at lower voltages.
Li-ion batteries are widely used in portable consumer electronic equipment because they offer one of the best energy-to-weight ratios - more than twice that of NiMH batteries - 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 condition. For this reason, 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 by incorporating an advanced battery-management chip, manufactured by ST, which enables safe and long-term reliability of Li-ion battery technology at affordable cost, even in applications as demanding as automotive powertrain systems.
“Accurate and reliable control of the battery charging and discharging cycles makes Li-ion technology applications the established choice for low-power consumer applications as well as a leading contender for future high-power�??, said Ph.D. MH Kim, the vice president of the Battery Research Institute of LG Chem. “As the world's number one supplier of power-management devices and one of the top suppliers of silicon chips to the automotive industry, ST was the natural choice to develop the silicon side of the battery pack to complement LG Chem's advanced Li-ion battery technology.�??
ST's battery-management chip is manufactured with the Company's proprietary BCD (Bipolar-CMOS-DMOS) technology, which combines digital logic circuits, precise analog measurement circuits and power-handling transistors in 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 a system. With this communication capability, as many as 32 battery-management chips can be connected in cascade to manage batteries that deliver up to 1600V to the electric motors.
BCD, often called smart power, is a semiconductor technology that allows ST to manufacture three fundamental components of electronic circuits on a single low-cost chip – digital logic for high-speed computation, analog circuits for high-precision measurement and control, and power transistors that manage the flow of high electric currents. ST pioneered the technology and has led the market ever since, with its smart-power products used in high volume applications ranging from printers and fax machines to hard disk drives and the devices that manage the movement of windows and mirrors in cars.
“Reducing the consumption of fossil fuels and carbon-dioxide emissions is an integral part of ST's product development strategy,�?? said Marco Monti, General Manager, Power Train and Safety Division, Automotive Product Group, STMicroelectronics. “We are proud that we've been able to adapt our power management and analog expertise with LG Chem to create a new solution that will enable Li-ion batteries to address increasingly higher power applications, from e-bikes to the most demanding public transport vehicles.�??
The LG Chem/ST solution reduces the cost and weight and increases the reliability of the Li-ion battery pack, enabling Li-ion technology to address new applications from electric scooters and bicycles to heavy trucks
