What are power cell and energy cells?
An energy cell will have better volumetric and gravimetric energy density; a power cell is to deliver higher power over energy density
How to make a power cell?
To make a power cell, the following strategies can be taken:
- Reduce electrode or ion diffusion length by
- (1) reducing active materials’ particle size;
- (2) reducing electrode coating weight;
- (3) increase electrode porosity to increase electrolyte/active materials interfaces;
- (4) adding more conductive materials to increase conductivity.
- Reduce resistance by
- (1) coating charge collectors;
- (2) use thicker and wider tags connected with charge collectors;
- (3) thinner separators;
- (4) electrolyte with higher ion conductivity;
- (5) stacked cells (multiple sheets stack together) has lower resistance than cylindrical or wound prismatic cells since they have less electrical tags per unit length/area of electrode and hence higher resistance
Trade-off between power and energy density cells
References
- M. J. Lain, J. Brandon, E. Kendrick, “Design Strategies for High Power vs. High Energy Lithium Ion Cells“, Batteries 2019, 5(4), 64
- Rui Zhao, Jie Liu, Junjie Gu, “The effects of electrode thickness on the electrochemical and thermal characteristics of lithium ion battery“, Applied Energy, Volume 139, 2015, Pages 220-229
- https://www.batterydesign.net/power-versus-energy-cells/