The air-conditioning compressor on the hybrid a/c system is used to cool the HV battery. There are two (2) evaporators; located one front and one rear. The rear evaporator in the battery compartment helps to cool the HV battery.
BTW - there is a recall for the early model Escape hybrids:
RECALL Subject : Motor Electronics Coolant Pump Failure
Report Receipt Date: SEP 03, 2014
NHTSA Campaign Number: 14V526000
Component(s): HYBRID PROPULSION SYSTEM
Potential Number of Units Affected: 70,209
All Products Associated with this Recall
Vehicle Make Model Model Year(s)
FORD ESCAPE 2005-2008
MERCURY MARINER 2006-2008
Manufacturer: Ford Motor Company
Ford Motor Company (Ford) is recalling certain model year 2005-2008 Ford Escape hybrid electric vehicles manufactured October 13, 2003, to June 20, 2008, and 2006-2008 Mercury Mariner hybrid electric vehicles manufactured June 10, 2005, to June 20, 2008. The coolant pump for the hybrid system may fail resulting in the hybrid electronics overheating.
If the hybrid electronics system overheats, it may shut down the powertrain, resulting in a stall-like condition, increasing the risk of a crash.
Ford will notify owners, and dealers will inspect and replace the original Motor Electronics Coolant (MEC) Pump with an improved brushless pump, free of charge. The recall is expected to begin on October 27, 2014. Owners may contact Ford customer service at 1-866-436-7332. Ford's number for this recall is 14S19.
Owners may also contact the National Highway Traffic Safety Administration Vehicle Safety Hotline at 1-888-327-4236 (TTY 1-800-424-9153), or go to www.safercar.gov