The California Air Resources Board (CARB) has mandated sales requirements in future years for zero-emission vehicle transit buses and medium- and heavy-duty (HD) trucks. Meeting these requirements and beyond will require improvements in battery performance and reduced battery costs. The strict CARB rules are a challenge because battery electric vehicle (BEVs) applications need to meet the constraints of low competitive cost, larger driving range, faster charging times, longer battery
life and available charging stations. Transit vehicles due to their size, weight, and often longer operating range add additional constraints on the performance characteristics of their batteries but more importantly cost when compared to other technologies. The vehicle application factors will include the cost to buy and maintain the battery, cycle life, charging time, charging station accessibility and cost, electricity prices, etc. There are three principal problems with present Lithium-ion batteries, especially in terms of designing heavy-duty battery-electric vehicles: (1) relatively low energy density (200-300 Wh/kg), which can limit vehicle range to less than required in some operational uses; (2) long charging time to a full change (2-3 hours); and (3) relatively high cost ($100-150/kWh). This research project will study battery technologies that can significantly increase the energy density to at least 500 Wh/kg or higher and reduce charging time to fifteen minutes or lower and have a cell cost to the original equipment manufacturer of $70/kWh or lower in a large battery pack (>500 kWh).
