By Jim Taylor, Editor MACS ACtion Magazine
We recently spent some time talking about the Chevrolet Volt’s thermal management systems for the battery packs. Not to be outdone, the Blue Oval folks have released some information on how the upcoming Ford Focus Electric will handle the problem. Here’s some consumer-level info, spliced and lightly pruned, from recent Ford press releases.
The all-new Ford Focus Electric, which debuts in late 2011 in the U.S. and 2012 in Europe, will be powered by a lithium-ion battery system that utilizes cooled and heated liquid to regulate battery temperature, extend battery life and maximize driving range.
Thermal management of lithium-ion battery systems is critical to the success of all-electric vehicles because extreme temperatures can affect performance, reliability, safety and durability. Ford has chosen an advanced active liquid-cooling and heating system to regulate the temperature of its lithium-ion battery packs, which are designed to operate under a range of ambient conditions.
Sherif Marakby, Ford director, Electrification Program and Engineering said, “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.
“A liquid-heated battery can accept a charge faster from the regenerative braking that recaptures kinetic energy and sends it back to the battery, essentially providing longer range for the customer in real world cold weather conditions. Additionally, since acceleration in an electric vehicle comes from the power available in the battery, the customer will have more power available if the battery is warmer.”
The active liquid cooling and heating system also enables the Focus Electric to automatically precondition the battery pack temperature during daily recharging. When the vehicle is plugged in to the power grid, the vehicle system will be able to warm up the battery on cold days and cool it down on hot days.
An active liquid system 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 efficiently accept charge energy and provide enough discharge power for expected vehicle performance.
The liquid cooling system also plays a role in charging the vehicle. When 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.
When having your mobile A/C system professionally serviced, insist on proper repair procedures and quality replacement parts. Insist on recovery and recycling so that refrigerant can be reused and not released into the atmosphere.
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