The all-electric Ford Focus will use liquid cooling/heating
for its lithium-ion battery system
One of the downsides of the lithium-ion battery systems used
in
electric vehicles is that their performance, reliability,
safety and durability can be negatively affected by extreme
temperatures. When the all-new Ford Focus Electric debuts later
this year in the U.S. it will be powered by a lithium-ion
battery – no news there. What is interesting, however, is that
the battery system will use cooled and heated liquid to regulate
battery temperature, which should extend battery life and
maximize driving range.
While air-cooling methods work well for many of today’s
smaller car battery systems, Ford said it needed a more
aggressive thermal management system for the larger, more
complex lithium-ion battery technology that will be powering the
company’s all-electric vehicles. Ford chose an active liquid
system that heats or chills a coolant before pumping it through
the battery cooling system. This loop regulates temperature
throughout the system against external conditions.
On hot days, chilled water absorbs heat from the batteries,
dispersing it through a radiator before pumping it through the
chiller again. On cold days, heated water warms the batteries,
gradually bringing the system’s temperature to a level that
allows it to provide enough discharge power for expected vehicle
performance.
Additionally, the system also plays a major role in charging
the vehicle. When the Focus is plugged in to recharge, the
vehicle control system will automatically precondition the
battery, if needed, to the optimal temperature before accepting
charge. If the battery is already at the optimal temperature,
the system will automatically accept charge and maintain an
optimal temperature.
“All-electric vehicles do not have a conventional engine on
board, so it is critical we maximize the performance of the
battery under various operating temperatures,” said Sherif
Marakby, Ford director, Electrification Program and Engineering.
“Active liquid systems are more effective than air systems at
regulating lithium-ion battery temperature. As a result, the
active liquid system on Focus Electric will play a key role in
providing our customers with the best performance possible.”
The Focus Electric, which will be released in the U.S. late
this year and in 2012 in Europe, is one of five electrified
vehicles Ford
will release over the next three years. The
Ford Transit Connect Electric small commercial van arrives
in late 2010, followed by two next-generation hybrid electric
vehicles, as well as a plug-in hybrid electric vehicle in North
America in 2012 and Europe in 2013.
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