Maxwell/Lishen alliance could offer ideal energy/power profile for hybrid vehicles
By Margery Conner, Technical Editor -- EDN, November 29, 2007
One of the challenges of designing with conventional lithium-ion batteries for HEVs (hybrid-electric vehicles) is that the energy-centric—rather than power-centric—batteries store a lot of energy but are slow to charge and discharge. The relatively-new lithium-iron-phosphate batteries are the reverse: They charge and discharge with gusto, but can store only a fraction of the energy of conventional lithium-ion batteries. However, lithium-iron-phosphate batteries are not the only devices with a rapid charge/discharge capability: Ultracapacitors, also called supercapacitors, can charge and discharge large bursts of power over an almost unlimited number of cycles. For this reason, ultracapacitors are popular in hybrid buses and commercial vehicles in which rapid charging and discharging allows the vehicles to use harvested energy from their braking system to charge and then discharge to power or to help provide power during acceleration.
With the goal of producing an efficient energy-storage/power-delivery system for HEVs, Maxwell Technologies, maker of vehicle-sized ultracapacitors, and Tianjin Lishen Battery, maker of lithium-ion cells, have formed an alliance to manufacture and market energy-storage products that combine their technologies. Designers need not know what’s inside these products. They could contain batteries, ultracapacitors, a battery/ultracapacitor combination, or hamsters on steroids—as long as the power-system “black box” fits the energy storage/power profile at the required cost and safety performance.
