A Case Study on Automotive Battery System Design - Title Page - MIT

Figure 6.1: Sealed-cabin-air coolingDeleted: , Toyota Prius, 2 nd genThe cabin air battery cooling architecture currently meets the requirements for most full hybridvehicles and is used across the industry in production vehicles. The general concept is thatcabin-air will be conditioned to an acceptable temperature by the vehicle occupants, which isalso suitable for the battery operations, described in Chapter 4.Although this is a viable solution for current applications, the future holds several uncertainties.First, many PHEVs or BEVs require additional power and energy, using more batteries than theFHEV. The physical size of the batteries limits the ability to package the battery inside thetrunk, as evidenced by the choices made by Nissan and GM in designing the Nissan Leaf BEVand Chevy Volt PHEV, both placing a very large battery pack beneath the vehicle. Second, asLi-ion batteries become well understood and technology advances, batteries may be operated athigher thermal loads with fewer cells in order to reduce cell cost and pack size. Similar trendshave been observed in the Lead-acid and Nickel-metal Hydride batteries. Third, PHEVs orBEVs may have increased thermal requirements due to the higher dependence on the electricpowertrain. Therefore, the cabin-air battery cooling architecture may not be sufficient for thesefuture thermal demands. To insure against the uncertainties in future battery temperature controlrequirements, alternative battery cooling architectures should be investigated during theadvanced battery system and vehicle architecture development phase.42