tailieunhanh - Lightweight Electric Hybrid Vehicle Design Episode 8

Tham khảo tài liệu 'lightweight electric hybrid vehicle design episode 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Battery fuel-cell EV design packages 113 LITHIUM-ION A high energy battery receiving considerable attention is the lithium-ion cell unit the development of which has been described by Nissan and Sony engineers1 who point out that because of the high cell voltage relatively few cells are required and better battery management is thus obtained. Accurate detection of battery state-of-charge is possible based on voltage measurement. In the battery system developed Fig. cell controllers and a battery controller work together to calculate battery power and remaining capacity and convey the results to the vehicle control unit. Charging current bypass circuits are also controlled on a cell-to-cell basis. Maximizing lifetime performance of an EV battery is seen by the authors to be as important as energy density level. Each module of the battery system has a thermistor to detect temperature and signal the controllers to activate cooling fans as necessary. Nissan are reported to be launching the Ultra EV in 1999 with lithium-ion batteries the car is said to return a 120 mile range per charge. Even further into the future lithium-polymer batteries are reported to be capable of giving 300 mile ranges. . 7 SUPERCAPA CITORS According to researchers at NEC the supercapacitor Fig. will be an important contributor to the energy efficient hybrid vehicle the absence of chemical reaction allowing a durable means of obtaining high energy charge discharge cycles. Tests have shown for multi-stop vehicle operations a 25-30 fuel saving was obtained in a compact hybrid vehicle fitted with regenerative braking. While energy density of existing non-automotive supercapacitors is only about 10 of that of lead-acid batteries the authors explain it is still possible to compensate for some of the weak points of conventional batteries. For effective power assist in hybrids supercapacitors need a working voltage of over 100 V alongside low equivalent series resistance and .