Typically, battery researchers use three parameters to define electrochemical performance: capacity, open-circuit voltage, and resistance. Capacity is a measure of the total charge stored in a battery. The open-circuit voltage is the voltage available from a battery with no current flow. It represents the battery's maximum voltage.
The document provides the basis for the development of homogenized performance metrics and a transparent reporting methodology at cell level, necessary for the reliable benchmarking of battery chemistries.
Here’s a quick glossary of the key lithium-ion (li-ion) performance metrics and why they matter. 1. Watt-hours Watt-hours measure how much energy (watts) a battery will deliver in an hour, and it’s the standard of measurement for a battery.
These determining factors include temperature, State of Charge (SOC), rest time, power rate, depth of discharge, and heat , , . Each of these factors contributes to the overall performance and its degradation process, whether the battery is operational or static.
In this rapidly evolving field, while key performance indicators can be readily accessed, the performance evaluation and comparison of battery technologies remain a challenging task, due to the huge variation in the quality and quantity of data reported and the lack of a common methodology.
The three KPIs considered in this document are the following: End-of-Discharge (EOD): The time condition at which a battery is fully discharged. EOD is reached when the voltage drops to a predefined end-of-discharge voltage. The time until this occurs is denoted here as tEOD.