from chemistry to pack
Prof James Marco WMG Energy Group Significant advances have been made in recent years in our understanding of the electrochemical performance of lithium-ion batteries (LIBs), their degradation, safety, manufacturability and recyclability – in part, through innovations in experimental methods and mathematical modelling. WMG is at the heart of this research through our involvement in projects … Read more
The Lucid Air battery design has single side 21700 busbars. This means the positive (+ve) and negative (-ve) connections to the cells are made on one end of the cell. Lucid Motors The busbars very neatly interlace, connecting the negatives on one group of parallel cells to the positives on the next parallel group of … Read more
Cell Gravimetric Energy Density with the units Wh/kg is a key cell metric. The optimum metric is a high Wh/kg. Hence: High nominal voltage High Ah capacity Low mass Perhaps the simplest of the battery metrics as the capacity of the cell is fairly easy to measure and the mass is just a set of … Read more
In the design of a normal lithium-ion cell the electrodes are composed of active materials on current collectors which are flat sheets of copper for the anode and aluminium for the cathode. These metal sheets are around 4-9 µm thick for copper and 15-25 µm thick for aluminium and have the active materials coated on … Read more
Although very rare, cell internal short circuits are a leading cause of battery thermal runaway. They are a major safety issue for any application of a battery pack. Hence there is a requirement to prevent them and to detect them. Common hazards of battery thermal runaway include toxic off-gassing, smoke, fire, and even an explosion. … Read more
Comparing power versus energy cells we see there are some fundamental differences. A high energy cell will have better volumetric and gravimetric energy density at the expense of the ability to deliver a high current. The power cell will have a low internal resistance and will be optimised to deliver current over energy density. Teardown … Read more
It is interesting to look at the cell energy density roadmaps and include the production energy density of the cylindrical cell. Why the cylindrical cell? Well, it’s the most complete cell in terms of function as it has a case that contains the working forces over the lifetime. It normally has a venting system and … Read more