US Patent 9960458 Battery systems having multiple independently controlled sets of battery cells

Provided are battery systems having multiple independently controlled sets of battery cells and method of using these systems to power, for example, drive trains of electric and hybrid vehicles. A battery system includes two or more sets of battery cells. Each set can be discharged and/or charged independently of another set based on different factors, such as a current power demand, power output capabilities of each set, and other like factors. One or multiple sets can be used to deliver power at any given time. In some embodiments, one set may be used to charge another set in the same power system. The same or different types of battery cells may be used in different sets. For example, one set may have battery cells having a higher power output capability, while another set may have battery cells with a higher energy density.