8 battery metrics that really matter to performance1. 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. Energy density and specific energy. Battery power, rate capability, or C-rate.
As more countries rely on renewable energy sources, battery systems must meet rising efficiency and longevity demands to stay relevant. Knowing key performance indicators of batteries, like Round Trip Efficiency (RTE) and State of Health (SOH), are critical to optimizing their operation and increasing overall performance.
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.
Why is performance evaluation and comparison of battery technologies so difficult?
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.
Temperature Management: Lowering battery temperatures will help mitigate energy losses and boost RTE. Controlled Charging/Discharging Rates: Slowed charging/discharging rates can help ensure energy efficiency. Balanced Charging Techniques: These techniques can optimize battery usage and prevent rapid degradation.
A set of key performance indicators (KPIs) have been designed to quantify the future performance and the current state of any battery regardless of its chemistry. The values of these KPIs depend upon various factors such as current, internal temperature, and ambient temperature. The three KPIs considered in this document are the following:
What impact will a battery technology development have on benchmarking?
Whilst this development will not have an immediate impact on the benchmarking of battery technologies, it will set a best practice for the reporting of results. The impact of implementing such methodologies should become apparent within 3-4 years of its adoption in research projects and journal publications.