Electrolytes for Improved High Temperature Performance
Lithium ion batteries that are exposed to HT extremes usually show signs of cell deformation due to cell gassing and this can lead to catastrophic failure of the cell. HT conditions always lead to decreased performance and shorter cell life. A properly formulated electrolyte can have a profound effect on the cell performance in this area.
Novolyte has developed many HT electrolytes by optimizing the ratios of solvents, salts, and additives in the electrolytes. The table below shows the performance of Novolyte HT electrolytes in cells stored at 60°C for 7 days versus a control electrolyte. By adjusting additive levels, cell swelling and impedance rise can be reduced and retained and recovered capacity can be improved, which also improve HT cycle life.
Testing is performed in 550mAh Li spinel/synthetic graphite prismatic cells. Similar results can be obtained for cells containing NMC, LFP, and LCO cathode materials.
| ELY formulation |
increase in swelling |
increase in impedance |
retained voltage |
retained capacity |
recovered capacity |
| Control |
1.98% |
22.71% |
99.03% |
89.50% |
91.96% |
| w/H5 additive |
1.15% |
19.08% |
98.91% |
90.15% |
93.79% |
| w/H4 additive |
2.15% |
42.75% |
98.79% |
83.01% |
86.53% |