The contributions of a number of scientists and innovators created our understanding of the forces of electricity, but Alessandro Volta is credited with the invention of the first battery in 1800. On its most basic level, a battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. Each cell contains a positive terminal, or cathode, and a negative terminal, or anode. Electrolytes allow ions to move between the electrodes and terminals, which allows current to flow out of the battery to perform work.

Advances in technology and materials have greatly increased the reliability, output, and density of modern battery systems, and economies of scale have dramatically reduced the associated cost. Continued innovation has created new technologies like electrochemical capacitors that can be charged and discharged simultaneously and instantly and provide an almost unlimited operational lifespan. The following pages offer greater insight into these technologies and the many applications that they are utilized for in creating a more robust and adaptable energy grid.
Lithium Ion (Li-Ion) Batteries

After Exxon chemist Stanley Whittingham developed the concept of lithium-ion batteries in the 1970s, Sony and Asahi Kasei created the first commercial product in 1991.
Redox Flow Batteries

Redox flow batteries (RFB) represent one class of electrochemical energy storage devices. The name “redox” refers to chemical reduction and oxidation reactions employed in the RFB to store energy in liquid electrolyte solutions which flow through a battery of electrochemical cells during charge and discharge. //

The separation of power and energy is a key distinction of RFBs, compared to other electrochemical storage systems. As described above, the system energy is stored in the volume of electrolyte, which can easily and economically be in the range of kilowatt-hours to tens of megawatt-hours, depending on the size of the storage tanks. The power capability of the system is determined by the size of the stack of electrochemical cells. The amount of electrolyte flowing in the electrochemical stack at any moment is rarely more than a few percent of the total amount of electrolyte present (for energy ratings corresponding to discharge at rated power for two to eight hours). Flow can easily be stopped during a fault condition. As a result, system vulnerability to uncontrolled energy release in the case of RFBs is limited by system architecture to a few percent of the total energy stored. This feature is in contrast with packaged, integrated cell storage architectures (lead-acid, NAS, Li Ion), where the full energy of the system is connected at all times and available for discharge.