A coin cell is a small, typically single-cell battery in the shape of a quarter dollar or the like, hence the name coin cell. Coin cells have two metal halves crimped together with a seal; one half is the positive terminal and the other the negative terminal, and inside are the electrodes and electrolyte. Their compact size and relatively stable output make them ideal for devices where space is limited and current requirements are low. As a commercial product, coin cells are often used to power small, low-drain devices like watches, calculators, remote controls, and IoT sensors. They are usually primary batteries (single-use), such as those made of lithium-metal chemistries (e.g., CR2032 is a standard 3V lithium coin cell). In R&D, coin cells are used to study materials at a small or fundamental scale. Often, coin cells are made and tested in a “half cells” configuration with an active material of interest as one elecrode, and lithium metal as the counter electrode, allowing fundamental properties of the active material to be studied. NOVONIX utilizes coin cells extensively for research and development of new battery materials. By fabricating half-cells with experimental anodes vs metallic lithium or experimental cathodes vs metallic lithium in coin cell format, NOVONIX can rapidly determine the charge efficiency (CE). CE is used to compare to similar materials and for designing full cell electrodes to ensure the proper N/P ratio is used. Electrochemical stability of novel materials can also be screened in half-cells using UHPC measurements to probe failure mechanisms such as constant voltage holds to measure the rate of electrochemical reactions at the material surface.
