Swiss battery manufacturer Leclanché has unveiled a new liquid electrolyte lithium battery that represents a “significant advance” in terms of safety compared to current batteries. The inclusion of a fire retardant additive to the electrolyte reduces the risk of a thermal runaway spreading by 80% inside the battery when it occurs a short circuit without compromising its performance.
The dendrites they are small rigid tree-like structures that grow inside a lithium battery like needle-like projections. These formations can perforate the separator that prevents the electrodes (cathode and anode) from touching, joining them and causing a short circuit that could set the battery on fire. An effect known as thermal runaway. This is a security issue key in hybrid and electric vehicles, since it can cause fires that threaten people, buildings and the environment.
The battery industry continues to devote considerable research and development resources to finding those materials that make solid electrolyte batteries possible in which dendrite generation, while possible, is much less important. However, as Leclanché CTO Pierre Blanc points out, “there is a critical need to improve the safety of current technology, that of high-density lithium-ion cells using liquid electrolyte. Most efforts, so far, negatively impact cell performance or longevity. Leclanché has been able to develop a high performance, high energy density lithium-ion cell that exhibits high safety characteristics without any negative impact on performance or longevity.”
by adding a special flame retardant additive to the composition of its electrolyte formula, Leclanché claims to have reduced the risk of a “thermal event” by almost 80%. This achievement has been validated by the German laboratory Intertek Germany, which works completely externally to the Swiss company. To verify the risk of thermal runaway, the laboratory carried out a series of nail penetration tests on a 60 Ah cell manufactured by Leclanché with this new additive. The test cells punctured causing an internal short circuit, but showed a much lower fire hazard than the same cells made without the flame retardant additives.
Leclanché cells are manufactured using a patented production technique. The electrodes are manufactured using a water-based process rather than using organic solvents such as NMP (a powerful solvent with low volatility used for a wide range of chemicals), which the company says significantly reduces the environmental footprint. . Leclanché says that his electrodes show high stability against the flame retardant additives contained in the new electrolyte so that cell performance is not compromised.
“Our breakthrough should encourage manufacturers hoping to move forward with their vehicle vehicle designs today, while the
next-generation solid-state batteries,” says Leclanché CEO Anil Srivastava. “Safe lithium-ion batteries have arrived and Leclanché has them.” The company’s new non-flammable cells will be available for production from the first quarter of 2023.
