Battery pack Ragone plot is power density versus energy density. There are a number of key battery metrics and this one is great to see where a design sits on the Power vs Energy Density Curve.
Note that the power is the peak power of the pack available for 10s. You could also plot the power as continuous.
In simple terms:
- Moving to the right on the x-axis is increasing in energy density
- Moving up the y-axis is increasing the power density
There are a number of factors that make it difficult to engineer a pack with very high power and high energy density.
The main factors are:
- Power versus Energy density cells
- thinner anode and cathodes increases power and decreases available energy
- Cooling more demanding in high power packs and hence increased mass and volume to package (cooling options)
- Thicker busbars – current carrying capability is proportional to the cross-sectional area
- High power = High currents => larger fuses and contactors
This post has been built based on the support and sponsorship of: AVANT Future Mobility, Quarto Technical Services, TAE Power Solutions, h.e.l group and The Limiting Factor.
The work Tzermias et al [1] looks at a methodology for optimising a hybrid energy storage system. Focussing on mixing different types of Li-ion batteries with a range of power-dense and energy-dense battery chemistries.
The approach is based on a Ragone plot and does not require the use of a detailed electrochemical model and thus allows for an effective evaluation of different energy storage technologies at an early stage of the design process.
Ragone plot analysis method for evaluating the actual Pareto-front-based mass saving when using a hybrid energy storage system compared to a single energy storage system for different application PE ratios based on the currently available battery technology performances.
References
- Tzermias, G.; Akehurst, S.; Burke, R.; Brace, C.; George, S.; Bernards, J.; Smith, C. Methodology for the Optimisation of Battery Hybrid Energy Storage Systems for Mass and Volume Using a Power-To-Energy Ratio Analysis. Batteries 2021
Battery Pack Metrics
When designing a battery pack you will always be asked to benchmark it.
Cell Metrics
There are a number of key cell metrics that we expect to see on any cell specification sheet.
See also: Key Pack Metrics
Valuable information!