Lithium-Ion Batteries

Technology, Principles, and Future Applications

What exactly is a Lithium-Ion Battery?

Batteries are defined as two or more electrochemical cells, electrically interconnected, each of which contains two electrodes and an electrolyte. The redox (oxidation-reduction) reactions that occur at these electrodes convert electrochemical energy into electrical energy. In everyday usage, 'battery' is also used to refer to a single cell.
Overview

Types of Batteries

Primary Batteries

In primary batteries, electrochemical reaction is not reversible. During discharging, the chemical compounds are permanently changed and electrical energy is released until original compounds are completely exhausted. Thus, cells can be used only once.

Secondary Batteries

In secondary batteries, electrochemical reaction is reversible. The original chemical compounds can be reconstituted by application of an electrical potential between electrodes, injecting energy into cell. Such cells can be discharged and recharged many times.

Principle, Construction & Working

Li-ion cell has a four-layer structure. The electrolytes are selected to ensure effective transport of Li-ion to the cathode during discharge. The type of conductivity is ionic in nature rather than electronic.

1.) Cathode:
Positive electrode (Lithium Cobalt Oxide) with thin aluminum foil collector.
2.) Anode:
Negative electrode (Specialty Carbon) with thin copper foil collector.
3.) Separator:
A fine porous polymer film.
4.) Electrolyte:
Lithium salt in an organic solvent.
Battery Construction Diagram
"It is definitely true that the fundamental enabling technology for electric cars is lithium-ion as a cell chemistry technology. In the absence of that, I don't think it's possible to make an electric car that is competitive with a gasoline car."
- Elon Musk
CEO, Tesla Motors and SpaceX