The advent of time-of-use (TOU) household electricity prices provides an opportunity for large lithium ion batteries to become a component of residential electrical power equipment for either storage or cogeneration. This project investigates household power use and cogeneration scenarios combined with lithium ion battery technology via simulation. The simulation treats transient battery charge and discharge based on electrochemical fundamentals. The analysis of both storage and cogeneration systems containing a batteries serves to demonstrate economic advantages of these types of power storage, as well as to identify size, materials, and performance criteria suitable for designing a lithium ion battery unit meeting real application demands.