Introduction The idea of combining electrical engines and internal combustion IC engines has a long history.. It was not until the end of the twentieth century that HEVs became a serious
Trang 1Hybrid Electric Vehicles: Batteries
U Ko¨ hler, Johnson Controls, Hannover, Germany
& 2009 Elsevier B.V All rights reserved.
Introduction
The idea of combining electrical engines and internal
combustion (IC) engines has a long history In 1901
J Lohner and F Porsche had already presented a first
hybrid electric vehicle (HEV) But this revolutionary
concept did not reach full maturity because the electrical
components were not developed The main concern was
the battery, a high-performing battery system with
ac-ceptable long-term endurance was not available at the
time The battery of the vehicle shown inFigure 1had a
weight of not less than 1800 kg
It was not until the end of the twentieth century that
HEVs became a serious alternative to vehicles propelled
by an internal combustion engine The Toyota Prius
appeared on the market in 1997 and was the first HEV
series vehicle in history A second version with improved
performance came out in the year 2003 (Figure 2)
Mainly its fuel-saving and extremely environmentally
friendly technology were the drivers for the considerable
market success since that time Triggered by the
tech-nical opportunities for drastically reducing fuel
con-sumption, other car manufacturers such as Honda and
Ford developed their own products Almost all car
pro-ducers in the world are now working on HEVs with the
clear goal of meeting the demand for fuel-saving and
environmentally compatible vehicles
There are several different vehicle concepts covered
under the term hybrid vehicle The following description
is to explain the differences in the technologies that have
consequences for the battery system used for them
Full Hybrid Electric Vehicles The most popular representative of a full hybrid electric vehicle (FHEV) (also called strong HEV) is the Toyota Prius (Figure 2) This type of vehicle uses the electrical storage system alone for relatively short periods in which the combustion engine would run with a lower energy efficiency Regenerative braking, in which reclaimed en-ergy is stored in batteries, is an important feature Pure electric driving is possible for short distances, but playing only a minor role It is regarded as an interesting feature for some special situations such as silent cruising in re-mote areas For energy efficiency reasons, the electrical drive system operates at voltage levels above 200 V The efficient combination of both, the combustion engine and the electrical drive system, enables a reduction of fuel consumption up to 40% in comparison to normal com-bustion engine-propelled vehicles
Mild Hybrid Electric Vehicles Mild hybrid electric vehicles (MHEVs) are a technical alternative to the FHEVs In comparison to the FHEV, the MHEV needs a lower degree of electrical power performance Electrical operation is mainly concerned with vehicle start and acceleration phases Regenerative charging under deceleration and braking contributes to a reduction of fuel consumption Pure electrical driving is not provided The electrical drive system of MHEVs operates typically at voltages between 100 and 200 V Earlier tendencies to realize MHEVs with 42 V systems
Figure 1 Porsche–Lohner hybrid electric vehicle (HEV) 1901.
Source: Wikipedia.
Figure 2 Toyota Prius hybrid electric vehicle (HEV) 2003 Source: Toyota website.
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