Guest Editorial: Keys to Successful Implementation of Lithium-Ion Batteries

Abstract

_ Energy is the number one cost of producing oil. Batteries offer new capabilities for reducing those costs and are one of the rare cases where we can improve both efficiency and capability. But what is critical for ensuring those benefits is the correct implementation and utilization of the technology. Batteries provide the greatest ROI when they are used directly alongside a primary power source—whether that is a diesel generator, gas engine, solar panel, utility-scale power plant, etc. Clearly a battery requires some method of charging, but the notion that a ‘hybrid’ approach likely makes the most sense is increasingly commonplace. However, it is easy to build a bad hybrid. Simply adding a battery onto an existing power system can result in a large capital expense with near zero benefit. Or the implementation of a battery could increase capability, reliability, and efficiency. Ensuring the latter of those two outcomes requires understanding three critical elements: the battery itself, the overall objectives, and the operational profile. What To Understand About the Battery Unsurprisingly, it is beneficial to increase one’s familiarity with the battery itself. The important thing to understand is that, from the standpoint of system level performance, batteries are fraught with tradeoffs. Of all the performance qualities of a battery—power, energy, weight, volume, cost, cycle life, safety—there is rarely any benefit to be gained in one aspect without sacrifice in at least one other. This is why it is important to match the needs of the application to a battery with the corresponding capabilities. On top of that, factors such as quality, thermal management, and the Battery Management System (BMS) will determine the ability of the system to deliver the performance that is promised on the spec sheet in the real world. Some of the most fundamental factors that must be considered in initial battery technology selection are power, energy, cycle life, and cost. Power and energy are intertwined and drive some of the most basic capabilities. They are also in direct tradeoff with each other—an increase in energy density almost always comes with a decrease in power density and vice versa. Assessing battery lifetime is complex, and battery technologies are available today that can easily perform tens of thousands of cycles, while many are rated for less than 1,000 cycles. Ultimately, lifetime will be determined by how the battery is operated in the field. The fact that cost is another critical factor certainly comes as no surprise. However, what is critical is not to be overly focused on cost, particularly in terms of $/kWh. Cost should be evaluated in terms of total cost of ownership over the lifetime.