Hybrid Vehicle Battery Technology - The Transition From NiMH To Li-Ion

The transition from nickel metal-hydride (NiMH) battery technology to lithium ion (Li-Ion) battery technology in hybrid electric vehicle applications presents both new opportunities and new challenges for vehicle implementation. Full recognition and acceptance of these opportunities and challenges is necessary for the vehicle manufacturer to efficiently proceed towards production implementation of Li-Ion battery technology in hybrid electric vehicles, even for those vehicle manufacturers who are already fully experienced with the significant prerequisite of NiMH battery technology implementation in vehicle applications. In this paper, potential opportunities and advantages for the vehicle manufacturer in areas including reduced width of the system operating voltage window, control algorithm and SOC determination simplification, improved energy efficiency, reduced heat generation, increased long-term stand capability, cell venting considerations, and reduced system weight, etc, will be discussed and quantified. Correspondingly, potential challenges for the vehicle manufacturer will be examined in areas including incorporation of abuse tolerant functionality, design validation implications, and recycling, etc.