During the past decade, lithium-ion batteries improved significantly in terms of volumetric energy density, which describes the amount of energy that can be contained within a given volume.
The higher the volumetric energy density is, the smaller the battery pack can be (assuming the same energy content).
It's not the only metric, as there is also the gravimetric energy density, which tells how much energy can be stored per weight unit. The higher it is, the lighter the battery pack can be.
In the new weekly presentation, the Department of Energy’s (DOE) Vehicle Technologies Office highlights how the volumetric energy density of lithium-ion batteries (industry average for battery packs) changed between 2008 and 2020.
The progress is tremendous, as in 2008 the number was only 55 Wh/Liter, while in 2020 it was 450 Wh/l, according to the study. That's an 8-fold increase in 12 years.
Progress (on the pack level):
- 2008: 55 Wh/l
- 2010: 90 Wh/l
- 2013: 140 Wh/l
- 2017: 250 Wh/l
- 2020: 450 Wh/l
We strongly believe that those industry average numbers have improved since then and in 2022 are even higher.
Energy Density of Lithium-ion Battery Packs, 2008-2020
"Source: Nitin Muralidharan, Ethan C. Self, Marm Dixit, Zhijia Du, Rachid Essehli, Ruhul Amin, Jagjit Nanda, Ilias Belharouak, Advanced Energy Materials, Next-Generation Cobalt-Free Cathodes – A Prospective Solution to the Battery Industry's Cobalt Problem, January 2022."
A lot depends on lithium-ion battery chemistry, as there is a very wide difference between particular solutions - up to an order of magnitude.
We often focus on the gravimetric energy density to make electric vehicles lighter and thus improve efficiency and range. However, the volumetric energy density is also very important for EVs, to make the battery smaller and fit inside the vehicle, increasing space for other elements and the passenger/cargo compartment.
CATL, the world's largest EV battery manufacturer, announced recently that its latest cell-to-pack (CTP) 3.0 battery systems will have a volumetric energy density of over 290 Wh/l in the case of LFP chemistry and over 450 Wh/l in the case of NCM chemistry.